linux_dsm_epyc7002/include/linux/device.h

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// SPDX-License-Identifier: GPL-2.0
/*
* device.h - generic, centralized driver model
*
* Copyright (c) 2001-2003 Patrick Mochel <mochel@osdl.org>
* Copyright (c) 2004-2009 Greg Kroah-Hartman <gregkh@suse.de>
* Copyright (c) 2008-2009 Novell Inc.
*
* See Documentation/driver-api/driver-model/ for more information.
*/
#ifndef _DEVICE_H_
#define _DEVICE_H_
#include <linux/dev_printk.h>
#include <linux/ioport.h>
#include <linux/kobject.h>
#include <linux/klist.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/compiler.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/pm.h>
#include <linux/atomic.h>
#include <linux/uidgid.h>
#include <linux/gfp.h>
#include <linux/overflow.h>
#include <linux/device/bus.h>
#include <linux/device/class.h>
#include <linux/device/driver.h>
#include <asm/device.h>
struct device;
struct device_private;
struct device_driver;
struct driver_private;
struct module;
struct class;
struct subsys_private;
struct device_node;
struct fwnode_handle;
struct iommu_ops;
struct iommu_group;
pinctrl: remove include file from <linux/device.h> When pulling the recent pinctrl merge, I was surprised by how a pinctrl-only pull request ended up rebuilding basically the whole kernel. The reason for that ended up being that <linux/device.h> included <linux/pinctrl/devinfo.h>, so any change to that file ended up causing pretty much every driver out there to be rebuilt. The reason for that was because 'struct device' has this in it: #ifdef CONFIG_PINCTRL struct dev_pin_info *pins; #endif but we already avoid header includes for these kinds of things in that header file, preferring to just use a forward-declaration of the structure instead. Exactly to avoid this kind of header dependency. Since some drivers seem to expect that <linux/pinctrl/devinfo.h> header to come in automatically, move the include to <linux/pinctrl/pinctrl.h> instead. It might be better to just make the includes more targeted, but I'm not going to review every driver. It would definitely be good to have a tool for finding and minimizing header dependencies automatically - or at least help with them. Right now we almost certainly end up having way too many of these things, and it's hard to test every single configuration. FWIW, you can get a sense of the "hotness" of a header file with something like this after doing a full build: find . -name '.*.o.cmd' -print0 | xargs -0 tail --lines=+2 | grep -v 'wildcard ' | tr ' \\' '\n' | sort | uniq -c | sort -n | less -S which isn't exact (there are other things in those '*.o.cmd' than just the dependencies, and the "--lines=+2" only removes the header), but might a useful approximation. With this patch, <linux/pinctrl/devinfo.h> drops to "only" having 833 users in the current x86-64 allmodconfig. In contrast, <linux/device.h> has 14857 build files including it directly or indirectly. Of course, the headers that absolutely _everybody_ includes (things like <linux/types.h> etc) get a score of 23000+. Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-03 07:44:14 +07:00
struct dev_pin_info;
struct dev_iommu;
Driver core: udev triggered device-<>driver binding We get two per-bus sysfs files: ls-l /sys/subsystem/usb drwxr-xr-x 2 root root 0 2007-02-16 16:42 devices drwxr-xr-x 7 root root 0 2007-02-16 14:55 drivers -rw-r--r-- 1 root root 4096 2007-02-16 16:42 drivers_autoprobe --w------- 1 root root 4096 2007-02-16 16:42 drivers_probe The flag "drivers_autoprobe" controls the behavior of the bus to bind devices by default, or just initialize the device and leave it alone. The command "drivers_probe" accepts a bus_id and the bus tries to bind a driver to this device. Systems who want to control the driver binding with udev, switch off the bus initiated probing: echo 0 > /sys/subsystem/usb/drivers_autoprobe echo 0 > /sys/subsystem/pcmcia/drivers_autoprobe ... and initiate the probing with udev rules like: ACTION=="add", SUBSYSTEM=="usb", ATTR{subsystem/drivers_probe}="$kernel" ACTION=="add", SUBSYSTEM=="pcmcia", ATTR{subsystem/drivers_probe}="$kernel" ... Custom driver binding can happen in earlier rules by something like: ACTION=="add", SUBSYSTEM=="usb", \ ATTRS{idVendor}=="1234", ATTRS{idProduct}=="5678" \ ATTR{subsystem/drivers/<custom-driver>/bind}="$kernel" This is intended to solve the modprobe.conf mess with "install-rules", custom bind/unbind-scripts and all the weird things people invented over the years. It should also provide the functionality "libusual" was supposed to do. With udev, one can just write a udev rule to drive all USB-disks at the third port of USB-hub by the "ub" driver, and everything else by usb-storage. One can also instruct udev to bind different wireless drivers to identical cards - just selected by the pcmcia slot-number, and whatever ... To use the mentioned rules, it needs udev version 106, to be able to write ATTR{}="$kernel" to sysfs files. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-02-16 23:33:36 +07:00
/**
* struct subsys_interface - interfaces to device functions
* @name: name of the device function
* @subsys: subsytem of the devices to attach to
* @node: the list of functions registered at the subsystem
* @add_dev: device hookup to device function handler
* @remove_dev: device hookup to device function handler
*
* Simple interfaces attached to a subsystem. Multiple interfaces can
* attach to a subsystem and its devices. Unlike drivers, they do not
* exclusively claim or control devices. Interfaces usually represent
* a specific functionality of a subsystem/class of devices.
*/
struct subsys_interface {
const char *name;
struct bus_type *subsys;
struct list_head node;
int (*add_dev)(struct device *dev, struct subsys_interface *sif);
void (*remove_dev)(struct device *dev, struct subsys_interface *sif);
};
int subsys_interface_register(struct subsys_interface *sif);
void subsys_interface_unregister(struct subsys_interface *sif);
int subsys_system_register(struct bus_type *subsys,
const struct attribute_group **groups);
int subsys_virtual_register(struct bus_type *subsys,
const struct attribute_group **groups);
/*
* The type of device, "struct device" is embedded in. A class
* or bus can contain devices of different types
* like "partitions" and "disks", "mouse" and "event".
* This identifies the device type and carries type-specific
* information, equivalent to the kobj_type of a kobject.
* If "name" is specified, the uevent will contain it in
* the DEVTYPE variable.
*/
struct device_type {
const char *name;
const struct attribute_group **groups;
int (*uevent)(struct device *dev, struct kobj_uevent_env *env);
char *(*devnode)(struct device *dev, umode_t *mode,
kuid_t *uid, kgid_t *gid);
void (*release)(struct device *dev);
Introduce new top level suspend and hibernation callbacks Introduce 'struct pm_ops' and 'struct pm_ext_ops' ('ext' meaning 'extended') representing suspend and hibernation operations for bus types, device classes, device types and device drivers. Modify the PM core to use 'struct pm_ops' and 'struct pm_ext_ops' objects, if defined, instead of the ->suspend(), ->resume(), ->suspend_late(), and ->resume_early() callbacks (the old callbacks will be considered as legacy and gradually phased out). The main purpose of doing this is to separate suspend (aka S2RAM and standby) callbacks from hibernation callbacks in such a way that the new callbacks won't take arguments and the semantics of each of them will be clearly specified. This has been requested for multiple times by many people, including Linus himself, and the reason is that within the current scheme if ->resume() is called, for example, it's difficult to say why it's been called (ie. is it a resume from RAM or from hibernation or a suspend/hibernation failure etc.?). The second purpose is to make the suspend/hibernation callbacks more flexible so that device drivers can handle more than they can within the current scheme. For example, some drivers may need to prevent new children of the device from being registered before their ->suspend() callbacks are executed or they may want to carry out some operations requiring the availability of some other devices, not directly bound via the parent-child relationship, in order to prepare for the execution of ->suspend(), etc. Ultimately, we'd like to stop using the freezing of tasks for suspend and therefore the drivers' suspend/hibernation code will have to take care of the handling of the user space during suspend/hibernation. That, in turn, would be difficult within the current scheme, without the new ->prepare() and ->complete() callbacks. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-05-21 04:00:01 +07:00
const struct dev_pm_ops *pm;
};
/* interface for exporting device attributes */
struct device_attribute {
struct attribute attr;
ssize_t (*show)(struct device *dev, struct device_attribute *attr,
char *buf);
ssize_t (*store)(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count);
};
struct dev_ext_attribute {
struct device_attribute attr;
void *var;
};
ssize_t device_show_ulong(struct device *dev, struct device_attribute *attr,
char *buf);
ssize_t device_store_ulong(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count);
ssize_t device_show_int(struct device *dev, struct device_attribute *attr,
char *buf);
ssize_t device_store_int(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count);
ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
char *buf);
ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count);
#define DEVICE_ATTR(_name, _mode, _show, _store) \
struct device_attribute dev_attr_##_name = __ATTR(_name, _mode, _show, _store)
#define DEVICE_ATTR_PREALLOC(_name, _mode, _show, _store) \
struct device_attribute dev_attr_##_name = \
__ATTR_PREALLOC(_name, _mode, _show, _store)
#define DEVICE_ATTR_RW(_name) \
struct device_attribute dev_attr_##_name = __ATTR_RW(_name)
#define DEVICE_ATTR_RO(_name) \
struct device_attribute dev_attr_##_name = __ATTR_RO(_name)
#define DEVICE_ATTR_WO(_name) \
struct device_attribute dev_attr_##_name = __ATTR_WO(_name)
#define DEVICE_ULONG_ATTR(_name, _mode, _var) \
struct dev_ext_attribute dev_attr_##_name = \
{ __ATTR(_name, _mode, device_show_ulong, device_store_ulong), &(_var) }
#define DEVICE_INT_ATTR(_name, _mode, _var) \
struct dev_ext_attribute dev_attr_##_name = \
{ __ATTR(_name, _mode, device_show_int, device_store_int), &(_var) }
#define DEVICE_BOOL_ATTR(_name, _mode, _var) \
struct dev_ext_attribute dev_attr_##_name = \
{ __ATTR(_name, _mode, device_show_bool, device_store_bool), &(_var) }
2012-05-15 00:30:03 +07:00
#define DEVICE_ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) \
struct device_attribute dev_attr_##_name = \
__ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store)
extern int device_create_file(struct device *device,
const struct device_attribute *entry);
extern void device_remove_file(struct device *dev,
const struct device_attribute *attr);
kernfs, sysfs, driver-core: implement kernfs_remove_self() and its wrappers Sometimes it's necessary to implement a node which wants to delete nodes including itself. This isn't straightforward because of kernfs active reference. While a file operation is in progress, an active reference is held and kernfs_remove() waits for all such references to drain before completing. For a self-deleting node, this is a deadlock as kernfs_remove() ends up waiting for an active reference that itself is sitting on top of. This currently is worked around in the sysfs layer using sysfs_schedule_callback() which makes such removals asynchronous. While it works, it's rather cumbersome and inherently breaks synchronicity of the operation - the file operation which triggered the operation may complete before the removal is finished (or even started) and the removal may fail asynchronously. If a removal operation is immmediately followed by another operation which expects the specific name to be available (e.g. removal followed by rename onto the same name), there's no way to make the latter operation reliable. The thing is there's no inherent reason for this to be asynchrnous. All that's necessary to do this synchronous is a dedicated operation which drops its own active ref and deactivates self. This patch implements kernfs_remove_self() and its wrappers in sysfs and driver core. kernfs_remove_self() is to be called from one of the file operations, drops the active ref the task is holding, removes the self node, and restores active ref to the dead node so that the ref is balanced afterwards. __kernfs_remove() is updated so that it takes an early exit if the target node is already fully removed so that the active ref restored by kernfs_remove_self() after removal doesn't confuse the deactivation path. This makes implementing self-deleting nodes very easy. The normal removal path doesn't even need to be changed to use kernfs_remove_self() for the self-deleting node. The method can invoke kernfs_remove_self() on itself before proceeding the normal removal path. kernfs_remove() invoked on the node by the normal deletion path will simply be ignored. This will replace sysfs_schedule_callback(). A subtle feature of sysfs_schedule_callback() is that it collapses multiple invocations - even if multiple removals are triggered, the removal callback is run only once. An equivalent effect can be achieved by testing the return value of kernfs_remove_self() - only the one which gets %true return value should proceed with actual deletion. All other instances of kernfs_remove_self() will wait till the enclosing kernfs operation which invoked the winning instance of kernfs_remove_self() finishes and then return %false. This trivially makes all users of kernfs_remove_self() automatically show correct synchronous behavior even when there are multiple concurrent operations - all "echo 1 > delete" instances will finish only after the whole operation is completed by one of the instances. Note that manipulation of active ref is implemented in separate public functions - kernfs_[un]break_active_protection(). kernfs_remove_self() is the only user at the moment but this will be used to cater to more complex cases. v2: For !CONFIG_SYSFS, dummy version kernfs_remove_self() was missing and sysfs_remove_file_self() had incorrect return type. Fix it. Reported by kbuild test bot. v3: kernfs_[un]break_active_protection() separated out from kernfs_remove_self() and exposed as public API. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-02-04 02:03:01 +07:00
extern bool device_remove_file_self(struct device *dev,
const struct device_attribute *attr);
extern int __must_check device_create_bin_file(struct device *dev,
const struct bin_attribute *attr);
extern void device_remove_bin_file(struct device *dev,
const struct bin_attribute *attr);
/* device resource management */
typedef void (*dr_release_t)(struct device *dev, void *res);
typedef int (*dr_match_t)(struct device *dev, void *res, void *match_data);
#ifdef CONFIG_DEBUG_DEVRES
extern void *__devres_alloc_node(dr_release_t release, size_t size, gfp_t gfp,
int nid, const char *name) __malloc;
#define devres_alloc(release, size, gfp) \
__devres_alloc_node(release, size, gfp, NUMA_NO_NODE, #release)
#define devres_alloc_node(release, size, gfp, nid) \
__devres_alloc_node(release, size, gfp, nid, #release)
#else
extern void *devres_alloc_node(dr_release_t release, size_t size, gfp_t gfp,
int nid) __malloc;
static inline void *devres_alloc(dr_release_t release, size_t size, gfp_t gfp)
{
return devres_alloc_node(release, size, gfp, NUMA_NO_NODE);
}
#endif
extern void devres_for_each_res(struct device *dev, dr_release_t release,
dr_match_t match, void *match_data,
void (*fn)(struct device *, void *, void *),
void *data);
extern void devres_free(void *res);
extern void devres_add(struct device *dev, void *res);
extern void *devres_find(struct device *dev, dr_release_t release,
dr_match_t match, void *match_data);
extern void *devres_get(struct device *dev, void *new_res,
dr_match_t match, void *match_data);
extern void *devres_remove(struct device *dev, dr_release_t release,
dr_match_t match, void *match_data);
extern int devres_destroy(struct device *dev, dr_release_t release,
dr_match_t match, void *match_data);
extern int devres_release(struct device *dev, dr_release_t release,
dr_match_t match, void *match_data);
/* devres group */
extern void * __must_check devres_open_group(struct device *dev, void *id,
gfp_t gfp);
extern void devres_close_group(struct device *dev, void *id);
extern void devres_remove_group(struct device *dev, void *id);
extern int devres_release_group(struct device *dev, void *id);
/* managed devm_k.alloc/kfree for device drivers */
extern void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp) __malloc;
extern __printf(3, 0)
char *devm_kvasprintf(struct device *dev, gfp_t gfp, const char *fmt,
va_list ap) __malloc;
extern __printf(3, 4)
char *devm_kasprintf(struct device *dev, gfp_t gfp, const char *fmt, ...) __malloc;
static inline void *devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)
{
return devm_kmalloc(dev, size, gfp | __GFP_ZERO);
}
static inline void *devm_kmalloc_array(struct device *dev,
size_t n, size_t size, gfp_t flags)
{
size_t bytes;
if (unlikely(check_mul_overflow(n, size, &bytes)))
return NULL;
return devm_kmalloc(dev, bytes, flags);
}
static inline void *devm_kcalloc(struct device *dev,
size_t n, size_t size, gfp_t flags)
{
return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
}
extern void devm_kfree(struct device *dev, const void *p);
extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp) __malloc;
extern const char *devm_kstrdup_const(struct device *dev,
const char *s, gfp_t gfp);
extern void *devm_kmemdup(struct device *dev, const void *src, size_t len,
gfp_t gfp);
extern unsigned long devm_get_free_pages(struct device *dev,
gfp_t gfp_mask, unsigned int order);
extern void devm_free_pages(struct device *dev, unsigned long addr);
void __iomem *devm_ioremap_resource(struct device *dev,
const struct resource *res);
void __iomem *devm_ioremap_resource_wc(struct device *dev,
const struct resource *res);
void __iomem *devm_of_iomap(struct device *dev,
struct device_node *node, int index,
resource_size_t *size);
/* allows to add/remove a custom action to devres stack */
int devm_add_action(struct device *dev, void (*action)(void *), void *data);
void devm_remove_action(struct device *dev, void (*action)(void *), void *data);
drivers/base/devres: introduce devm_release_action() Patch series "mm/devm_memremap_pages: Fix page release race", v2. Logan audited the devm_memremap_pages() shutdown path and noticed that it was possible to proceed to arch_remove_memory() before all potential page references have been reaped. Introduce a new ->cleanup() callback to do the work of waiting for any straggling page references and then perform the percpu_ref_exit() in devm_memremap_pages_release() context. For p2pdma this involves some deeper reworks to reference count resources on a per-instance basis rather than a per pci-device basis. A modified genalloc api is introduced to convey a driver-private pointer through gen_pool_{alloc,free}() interfaces. Also, a devm_memunmap_pages() api is introduced since p2pdma does not auto-release resources on a setup failure. The dax and pmem changes pass the nvdimm unit tests, and the p2pdma changes should now pass testing with the pci_p2pdma_release() fix. Jrme, how does this look for HMM? This patch (of 6): The devm_add_action() facility allows a resource allocation routine to add custom devm semantics. One such user is devm_memremap_pages(). There is now a need to manually trigger devm_memremap_pages_release(). Introduce devm_release_action() so the release action can be triggered via a new devm_memunmap_pages() api in a follow-on change. Link: http://lkml.kernel.org/r/155727336530.292046.2926860263201336366.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Logan Gunthorpe <logang@deltatee.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: "Jérôme Glisse" <jglisse@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-06-14 05:56:18 +07:00
void devm_release_action(struct device *dev, void (*action)(void *), void *data);
static inline int devm_add_action_or_reset(struct device *dev,
void (*action)(void *), void *data)
{
int ret;
ret = devm_add_action(dev, action, data);
if (ret)
action(data);
return ret;
}
/**
* devm_alloc_percpu - Resource-managed alloc_percpu
* @dev: Device to allocate per-cpu memory for
* @type: Type to allocate per-cpu memory for
*
* Managed alloc_percpu. Per-cpu memory allocated with this function is
* automatically freed on driver detach.
*
* RETURNS:
* Pointer to allocated memory on success, NULL on failure.
*/
#define devm_alloc_percpu(dev, type) \
((typeof(type) __percpu *)__devm_alloc_percpu((dev), sizeof(type), \
__alignof__(type)))
void __percpu *__devm_alloc_percpu(struct device *dev, size_t size,
size_t align);
void devm_free_percpu(struct device *dev, void __percpu *pdata);
iommu sg merging: add device_dma_parameters structure IOMMUs merges scatter/gather segments without considering a low level driver's restrictions. The problem is that IOMMUs can't access to the limitations because they are in request_queue. This patchset introduces a new structure, device_dma_parameters, including dma information. A pointer to device_dma_parameters is added to struct device. The bus specific structures (like pci_dev) includes device_dma_parameters. Low level drivers can use dma_set_max_seg_size to tell IOMMUs about the restrictions. We can move more dma stuff in struct device (like dma_mask) to struct device_dma_parameters later (needs some cleanups before that). This includes patches for all the IOMMUs that could merge sg (x86_64, ppc, IA64, alpha, sparc64, and parisc) though only the ppc patch was tested. The patches for other IOMMUs are only compile tested. This patch: Add a new structure, device_dma_parameters, including dma information. A pointer to device_dma_parameters is added to struct device. - there are only max_segment_size and segment_boundary_mask there but we'll move more dma stuff in struct device (like dma_mask) to struct device_dma_parameters later. segment_boundary_mask is not supported yet. - new accessors for the dma parameters are added. So we can easily change where to place struct device_dma_parameters in the future. - dma_get_max_seg_size returns 64K if dma_parms in struct device isn't set up properly. 64K is the default max_segment_size in the block layer. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Acked-by: Jeff Garzik <jeff@garzik.org> Cc: James Bottomley <James.Bottomley@steeleye.com> Acked-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 13:27:55 +07:00
struct device_dma_parameters {
/*
* a low level driver may set these to teach IOMMU code about
* sg limitations.
*/
unsigned int max_segment_size;
unsigned long segment_boundary_mask;
};
/**
* struct device_connection - Device Connection Descriptor
* @fwnode: The device node of the connected device
* @endpoint: The names of the two devices connected together
* @id: Unique identifier for the connection
* @list: List head, private, for internal use only
*
* NOTE: @fwnode is not used together with @endpoint. @fwnode is used when
* platform firmware defines the connection. When the connection is registered
* with device_connection_add() @endpoint is used instead.
*/
struct device_connection {
struct fwnode_handle *fwnode;
const char *endpoint[2];
const char *id;
struct list_head list;
};
typedef void *(*devcon_match_fn_t)(struct device_connection *con, int ep,
void *data);
void *fwnode_connection_find_match(struct fwnode_handle *fwnode,
const char *con_id, void *data,
devcon_match_fn_t match);
void *device_connection_find_match(struct device *dev, const char *con_id,
void *data, devcon_match_fn_t match);
struct device *device_connection_find(struct device *dev, const char *con_id);
void device_connection_add(struct device_connection *con);
void device_connection_remove(struct device_connection *con);
/**
* device_connections_add - Add multiple device connections at once
* @cons: Zero terminated array of device connection descriptors
*/
static inline void device_connections_add(struct device_connection *cons)
{
struct device_connection *c;
for (c = cons; c->endpoint[0]; c++)
device_connection_add(c);
}
/**
* device_connections_remove - Remove multiple device connections at once
* @cons: Zero terminated array of device connection descriptors
*/
static inline void device_connections_remove(struct device_connection *cons)
{
struct device_connection *c;
for (c = cons; c->endpoint[0]; c++)
device_connection_remove(c);
}
driver core: Functional dependencies tracking support Currently, there is a problem with taking functional dependencies between devices into account. What I mean by a "functional dependency" is when the driver of device B needs device A to be functional and (generally) its driver to be present in order to work properly. This has certain consequences for power management (suspend/resume and runtime PM ordering) and shutdown ordering of these devices. In general, it also implies that the driver of A needs to be working for B to be probed successfully and it cannot be unbound from the device before the B's driver. Support for representing those functional dependencies between devices is added here to allow the driver core to track them and act on them in certain cases where applicable. The argument for doing that in the driver core is that there are quite a few distinct use cases involving device dependencies, they are relatively hard to get right in a driver (if one wants to address all of them properly) and it only gets worse if multiplied by the number of drivers potentially needing to do it. Morever, at least one case (asynchronous system suspend/resume) cannot be handled in a single driver at all, because it requires the driver of A to wait for B to suspend (during system suspend) and the driver of B to wait for A to resume (during system resume). For this reason, represent dependencies between devices as "links", with the help of struct device_link objects each containing pointers to the "linked" devices, a list node for each of them, status information, flags, and an RCU head for synchronization. Also add two new list heads, representing the lists of links to the devices that depend on the given one (consumers) and to the devices depended on by it (suppliers), and a "driver presence status" field (needed for figuring out initial states of device links) to struct device. The entire data structure consisting of all of the lists of link objects for all devices is protected by a mutex (for link object addition/removal and for list walks during device driver probing and removal) and by SRCU (for list walking in other case that will be introduced by subsequent change sets). If CONFIG_SRCU is not selected, however, an rwsem is used for protecting the entire data structure. In addition, each link object has an internal status field whose value reflects whether or not drivers are bound to the devices pointed to by the link or probing/removal of their drivers is in progress etc. That field is only modified under the device links mutex, but it may be read outside of it in some cases (introduced by subsequent change sets), so modifications of it are annotated with WRITE_ONCE(). New links are added by calling device_link_add() which takes three arguments: pointers to the devices in question and flags. In particular, if DL_FLAG_STATELESS is set in the flags, the link status is not to be taken into account for this link and the driver core will not manage it. In turn, if DL_FLAG_AUTOREMOVE is set in the flags, the driver core will remove the link automatically when the consumer device driver unbinds from it. One of the actions carried out by device_link_add() is to reorder the lists used for device shutdown and system suspend/resume to put the consumer device along with all of its children and all of its consumers (and so on, recursively) to the ends of those lists in order to ensure the right ordering between all of the supplier and consumer devices. For this reason, it is not possible to create a link between two devices if the would-be supplier device already depends on the would-be consumer device as either a direct descendant of it or a consumer of one of its direct descendants or one of its consumers and so on. There are two types of link objects, persistent and non-persistent. The persistent ones stay around until one of the target devices is deleted, while the non-persistent ones are removed automatically when the consumer driver unbinds from its device (ie. they are assumed to be valid only as long as the consumer device has a driver bound to it). Persistent links are created by default and non-persistent links are created when the DL_FLAG_AUTOREMOVE flag is passed to device_link_add(). Both persistent and non-persistent device links can be deleted with an explicit call to device_link_del(). Links created without the DL_FLAG_STATELESS flag set are managed by the driver core using a simple state machine. There are 5 states each link can be in: DORMANT (unused), AVAILABLE (the supplier driver is present and functional), CONSUMER_PROBE (the consumer driver is probing), ACTIVE (both supplier and consumer drivers are present and functional), and SUPPLIER_UNBIND (the supplier driver is unbinding). The driver core updates the link state automatically depending on what happens to the linked devices and for each link state specific actions are taken in addition to that. For example, if the supplier driver unbinds from its device, the driver core will also unbind the drivers of all of its consumers automatically under the assumption that they cannot function properly without the supplier. Analogously, the driver core will only allow the consumer driver to bind to its device if the supplier driver is present and functional (ie. the link is in the AVAILABLE state). If that's not the case, it will rely on the existing deferred probing mechanism to wait for the supplier driver to become available. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-30 23:32:16 +07:00
/**
* enum device_link_state - Device link states.
* @DL_STATE_NONE: The presence of the drivers is not being tracked.
* @DL_STATE_DORMANT: None of the supplier/consumer drivers is present.
* @DL_STATE_AVAILABLE: The supplier driver is present, but the consumer is not.
* @DL_STATE_CONSUMER_PROBE: The consumer is probing (supplier driver present).
* @DL_STATE_ACTIVE: Both the supplier and consumer drivers are present.
* @DL_STATE_SUPPLIER_UNBIND: The supplier driver is unbinding.
*/
enum device_link_state {
DL_STATE_NONE = -1,
DL_STATE_DORMANT = 0,
DL_STATE_AVAILABLE,
DL_STATE_CONSUMER_PROBE,
DL_STATE_ACTIVE,
DL_STATE_SUPPLIER_UNBIND,
};
/*
* Device link flags.
*
driver core: Remove device link creation limitation If device_link_add() is called for a consumer/supplier pair with an existing device link between them and the existing link's type is not in agreement with the flags passed to that function by its caller, NULL will be returned. That is seriously inconvenient, because it forces the callers of device_link_add() to worry about what others may or may not do even if that is not relevant to them for any other reasons. It turns out, however, that this limitation can be made go away relatively easily. The underlying observation is that if DL_FLAG_STATELESS has been passed to device_link_add() in flags for the given consumer/supplier pair at least once, calling either device_link_del() or device_link_remove() to release the link returned by it should work, but there are no other requirements associated with that flag. In turn, if at least one of the callers of device_link_add() for the given consumer/supplier pair has not passed DL_FLAG_STATELESS to it in flags, the driver core should track the status of the link and act on it as appropriate (ie. the link should be treated as "managed"). This means that DL_FLAG_STATELESS needs to be set for managed device links and it should be valid to call device_link_del() or device_link_remove() to drop references to them in certain sutiations. To allow that to happen, introduce a new (internal) device link flag called DL_FLAG_MANAGED and make device_link_add() set it automatically whenever DL_FLAG_STATELESS is not passed to it. Also make it take additional references to existing device links that were previously stateless (that is, with DL_FLAG_STATELESS set and DL_FLAG_MANAGED unset) and will need to be managed going forward and initialize their status (which has been DL_STATE_NONE so far). Accordingly, when a managed device link is dropped automatically by the driver core, make it clear DL_FLAG_MANAGED, reset the link's status back to DL_STATE_NONE and drop the reference to it associated with DL_FLAG_MANAGED instead of just deleting it right away (to allow it to stay around in case it still needs to be released explicitly by someone). With that, since setting DL_FLAG_STATELESS doesn't mean that the device link in question is not managed any more, replace all of the status-tracking checks against DL_FLAG_STATELESS with analogous checks against DL_FLAG_MANAGED and update the documentation to reflect these changes. While at it, make device_link_add() reject flags that it does not recognize, including DL_FLAG_MANAGED. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Saravana Kannan <saravanak@google.com> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Review-by: Saravana Kannan <saravanak@google.com> Link: https://lore.kernel.org/r/2305283.AStDPdUUnE@kreacher Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-16 22:21:06 +07:00
* STATELESS: The core will not remove this link automatically.
* AUTOREMOVE_CONSUMER: Remove the link automatically on consumer driver unbind.
* PM_RUNTIME: If set, the runtime PM framework will use this link.
* RPM_ACTIVE: Run pm_runtime_get_sync() on the supplier during link creation.
* AUTOREMOVE_SUPPLIER: Remove the link automatically on supplier driver unbind.
* AUTOPROBE_CONSUMER: Probe consumer driver automatically after supplier binds.
driver core: Remove device link creation limitation If device_link_add() is called for a consumer/supplier pair with an existing device link between them and the existing link's type is not in agreement with the flags passed to that function by its caller, NULL will be returned. That is seriously inconvenient, because it forces the callers of device_link_add() to worry about what others may or may not do even if that is not relevant to them for any other reasons. It turns out, however, that this limitation can be made go away relatively easily. The underlying observation is that if DL_FLAG_STATELESS has been passed to device_link_add() in flags for the given consumer/supplier pair at least once, calling either device_link_del() or device_link_remove() to release the link returned by it should work, but there are no other requirements associated with that flag. In turn, if at least one of the callers of device_link_add() for the given consumer/supplier pair has not passed DL_FLAG_STATELESS to it in flags, the driver core should track the status of the link and act on it as appropriate (ie. the link should be treated as "managed"). This means that DL_FLAG_STATELESS needs to be set for managed device links and it should be valid to call device_link_del() or device_link_remove() to drop references to them in certain sutiations. To allow that to happen, introduce a new (internal) device link flag called DL_FLAG_MANAGED and make device_link_add() set it automatically whenever DL_FLAG_STATELESS is not passed to it. Also make it take additional references to existing device links that were previously stateless (that is, with DL_FLAG_STATELESS set and DL_FLAG_MANAGED unset) and will need to be managed going forward and initialize their status (which has been DL_STATE_NONE so far). Accordingly, when a managed device link is dropped automatically by the driver core, make it clear DL_FLAG_MANAGED, reset the link's status back to DL_STATE_NONE and drop the reference to it associated with DL_FLAG_MANAGED instead of just deleting it right away (to allow it to stay around in case it still needs to be released explicitly by someone). With that, since setting DL_FLAG_STATELESS doesn't mean that the device link in question is not managed any more, replace all of the status-tracking checks against DL_FLAG_STATELESS with analogous checks against DL_FLAG_MANAGED and update the documentation to reflect these changes. While at it, make device_link_add() reject flags that it does not recognize, including DL_FLAG_MANAGED. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Saravana Kannan <saravanak@google.com> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Review-by: Saravana Kannan <saravanak@google.com> Link: https://lore.kernel.org/r/2305283.AStDPdUUnE@kreacher Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-16 22:21:06 +07:00
* MANAGED: The core tracks presence of supplier/consumer drivers (internal).
* SYNC_STATE_ONLY: Link only affects sync_state() behavior.
driver core: Functional dependencies tracking support Currently, there is a problem with taking functional dependencies between devices into account. What I mean by a "functional dependency" is when the driver of device B needs device A to be functional and (generally) its driver to be present in order to work properly. This has certain consequences for power management (suspend/resume and runtime PM ordering) and shutdown ordering of these devices. In general, it also implies that the driver of A needs to be working for B to be probed successfully and it cannot be unbound from the device before the B's driver. Support for representing those functional dependencies between devices is added here to allow the driver core to track them and act on them in certain cases where applicable. The argument for doing that in the driver core is that there are quite a few distinct use cases involving device dependencies, they are relatively hard to get right in a driver (if one wants to address all of them properly) and it only gets worse if multiplied by the number of drivers potentially needing to do it. Morever, at least one case (asynchronous system suspend/resume) cannot be handled in a single driver at all, because it requires the driver of A to wait for B to suspend (during system suspend) and the driver of B to wait for A to resume (during system resume). For this reason, represent dependencies between devices as "links", with the help of struct device_link objects each containing pointers to the "linked" devices, a list node for each of them, status information, flags, and an RCU head for synchronization. Also add two new list heads, representing the lists of links to the devices that depend on the given one (consumers) and to the devices depended on by it (suppliers), and a "driver presence status" field (needed for figuring out initial states of device links) to struct device. The entire data structure consisting of all of the lists of link objects for all devices is protected by a mutex (for link object addition/removal and for list walks during device driver probing and removal) and by SRCU (for list walking in other case that will be introduced by subsequent change sets). If CONFIG_SRCU is not selected, however, an rwsem is used for protecting the entire data structure. In addition, each link object has an internal status field whose value reflects whether or not drivers are bound to the devices pointed to by the link or probing/removal of their drivers is in progress etc. That field is only modified under the device links mutex, but it may be read outside of it in some cases (introduced by subsequent change sets), so modifications of it are annotated with WRITE_ONCE(). New links are added by calling device_link_add() which takes three arguments: pointers to the devices in question and flags. In particular, if DL_FLAG_STATELESS is set in the flags, the link status is not to be taken into account for this link and the driver core will not manage it. In turn, if DL_FLAG_AUTOREMOVE is set in the flags, the driver core will remove the link automatically when the consumer device driver unbinds from it. One of the actions carried out by device_link_add() is to reorder the lists used for device shutdown and system suspend/resume to put the consumer device along with all of its children and all of its consumers (and so on, recursively) to the ends of those lists in order to ensure the right ordering between all of the supplier and consumer devices. For this reason, it is not possible to create a link between two devices if the would-be supplier device already depends on the would-be consumer device as either a direct descendant of it or a consumer of one of its direct descendants or one of its consumers and so on. There are two types of link objects, persistent and non-persistent. The persistent ones stay around until one of the target devices is deleted, while the non-persistent ones are removed automatically when the consumer driver unbinds from its device (ie. they are assumed to be valid only as long as the consumer device has a driver bound to it). Persistent links are created by default and non-persistent links are created when the DL_FLAG_AUTOREMOVE flag is passed to device_link_add(). Both persistent and non-persistent device links can be deleted with an explicit call to device_link_del(). Links created without the DL_FLAG_STATELESS flag set are managed by the driver core using a simple state machine. There are 5 states each link can be in: DORMANT (unused), AVAILABLE (the supplier driver is present and functional), CONSUMER_PROBE (the consumer driver is probing), ACTIVE (both supplier and consumer drivers are present and functional), and SUPPLIER_UNBIND (the supplier driver is unbinding). The driver core updates the link state automatically depending on what happens to the linked devices and for each link state specific actions are taken in addition to that. For example, if the supplier driver unbinds from its device, the driver core will also unbind the drivers of all of its consumers automatically under the assumption that they cannot function properly without the supplier. Analogously, the driver core will only allow the consumer driver to bind to its device if the supplier driver is present and functional (ie. the link is in the AVAILABLE state). If that's not the case, it will rely on the existing deferred probing mechanism to wait for the supplier driver to become available. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-30 23:32:16 +07:00
*/
#define DL_FLAG_STATELESS BIT(0)
#define DL_FLAG_AUTOREMOVE_CONSUMER BIT(1)
#define DL_FLAG_PM_RUNTIME BIT(2)
#define DL_FLAG_RPM_ACTIVE BIT(3)
#define DL_FLAG_AUTOREMOVE_SUPPLIER BIT(4)
#define DL_FLAG_AUTOPROBE_CONSUMER BIT(5)
driver core: Remove device link creation limitation If device_link_add() is called for a consumer/supplier pair with an existing device link between them and the existing link's type is not in agreement with the flags passed to that function by its caller, NULL will be returned. That is seriously inconvenient, because it forces the callers of device_link_add() to worry about what others may or may not do even if that is not relevant to them for any other reasons. It turns out, however, that this limitation can be made go away relatively easily. The underlying observation is that if DL_FLAG_STATELESS has been passed to device_link_add() in flags for the given consumer/supplier pair at least once, calling either device_link_del() or device_link_remove() to release the link returned by it should work, but there are no other requirements associated with that flag. In turn, if at least one of the callers of device_link_add() for the given consumer/supplier pair has not passed DL_FLAG_STATELESS to it in flags, the driver core should track the status of the link and act on it as appropriate (ie. the link should be treated as "managed"). This means that DL_FLAG_STATELESS needs to be set for managed device links and it should be valid to call device_link_del() or device_link_remove() to drop references to them in certain sutiations. To allow that to happen, introduce a new (internal) device link flag called DL_FLAG_MANAGED and make device_link_add() set it automatically whenever DL_FLAG_STATELESS is not passed to it. Also make it take additional references to existing device links that were previously stateless (that is, with DL_FLAG_STATELESS set and DL_FLAG_MANAGED unset) and will need to be managed going forward and initialize their status (which has been DL_STATE_NONE so far). Accordingly, when a managed device link is dropped automatically by the driver core, make it clear DL_FLAG_MANAGED, reset the link's status back to DL_STATE_NONE and drop the reference to it associated with DL_FLAG_MANAGED instead of just deleting it right away (to allow it to stay around in case it still needs to be released explicitly by someone). With that, since setting DL_FLAG_STATELESS doesn't mean that the device link in question is not managed any more, replace all of the status-tracking checks against DL_FLAG_STATELESS with analogous checks against DL_FLAG_MANAGED and update the documentation to reflect these changes. While at it, make device_link_add() reject flags that it does not recognize, including DL_FLAG_MANAGED. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Saravana Kannan <saravanak@google.com> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Review-by: Saravana Kannan <saravanak@google.com> Link: https://lore.kernel.org/r/2305283.AStDPdUUnE@kreacher Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-16 22:21:06 +07:00
#define DL_FLAG_MANAGED BIT(6)
#define DL_FLAG_SYNC_STATE_ONLY BIT(7)
driver core: Functional dependencies tracking support Currently, there is a problem with taking functional dependencies between devices into account. What I mean by a "functional dependency" is when the driver of device B needs device A to be functional and (generally) its driver to be present in order to work properly. This has certain consequences for power management (suspend/resume and runtime PM ordering) and shutdown ordering of these devices. In general, it also implies that the driver of A needs to be working for B to be probed successfully and it cannot be unbound from the device before the B's driver. Support for representing those functional dependencies between devices is added here to allow the driver core to track them and act on them in certain cases where applicable. The argument for doing that in the driver core is that there are quite a few distinct use cases involving device dependencies, they are relatively hard to get right in a driver (if one wants to address all of them properly) and it only gets worse if multiplied by the number of drivers potentially needing to do it. Morever, at least one case (asynchronous system suspend/resume) cannot be handled in a single driver at all, because it requires the driver of A to wait for B to suspend (during system suspend) and the driver of B to wait for A to resume (during system resume). For this reason, represent dependencies between devices as "links", with the help of struct device_link objects each containing pointers to the "linked" devices, a list node for each of them, status information, flags, and an RCU head for synchronization. Also add two new list heads, representing the lists of links to the devices that depend on the given one (consumers) and to the devices depended on by it (suppliers), and a "driver presence status" field (needed for figuring out initial states of device links) to struct device. The entire data structure consisting of all of the lists of link objects for all devices is protected by a mutex (for link object addition/removal and for list walks during device driver probing and removal) and by SRCU (for list walking in other case that will be introduced by subsequent change sets). If CONFIG_SRCU is not selected, however, an rwsem is used for protecting the entire data structure. In addition, each link object has an internal status field whose value reflects whether or not drivers are bound to the devices pointed to by the link or probing/removal of their drivers is in progress etc. That field is only modified under the device links mutex, but it may be read outside of it in some cases (introduced by subsequent change sets), so modifications of it are annotated with WRITE_ONCE(). New links are added by calling device_link_add() which takes three arguments: pointers to the devices in question and flags. In particular, if DL_FLAG_STATELESS is set in the flags, the link status is not to be taken into account for this link and the driver core will not manage it. In turn, if DL_FLAG_AUTOREMOVE is set in the flags, the driver core will remove the link automatically when the consumer device driver unbinds from it. One of the actions carried out by device_link_add() is to reorder the lists used for device shutdown and system suspend/resume to put the consumer device along with all of its children and all of its consumers (and so on, recursively) to the ends of those lists in order to ensure the right ordering between all of the supplier and consumer devices. For this reason, it is not possible to create a link between two devices if the would-be supplier device already depends on the would-be consumer device as either a direct descendant of it or a consumer of one of its direct descendants or one of its consumers and so on. There are two types of link objects, persistent and non-persistent. The persistent ones stay around until one of the target devices is deleted, while the non-persistent ones are removed automatically when the consumer driver unbinds from its device (ie. they are assumed to be valid only as long as the consumer device has a driver bound to it). Persistent links are created by default and non-persistent links are created when the DL_FLAG_AUTOREMOVE flag is passed to device_link_add(). Both persistent and non-persistent device links can be deleted with an explicit call to device_link_del(). Links created without the DL_FLAG_STATELESS flag set are managed by the driver core using a simple state machine. There are 5 states each link can be in: DORMANT (unused), AVAILABLE (the supplier driver is present and functional), CONSUMER_PROBE (the consumer driver is probing), ACTIVE (both supplier and consumer drivers are present and functional), and SUPPLIER_UNBIND (the supplier driver is unbinding). The driver core updates the link state automatically depending on what happens to the linked devices and for each link state specific actions are taken in addition to that. For example, if the supplier driver unbinds from its device, the driver core will also unbind the drivers of all of its consumers automatically under the assumption that they cannot function properly without the supplier. Analogously, the driver core will only allow the consumer driver to bind to its device if the supplier driver is present and functional (ie. the link is in the AVAILABLE state). If that's not the case, it will rely on the existing deferred probing mechanism to wait for the supplier driver to become available. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-30 23:32:16 +07:00
/**
* struct device_link - Device link representation.
* @supplier: The device on the supplier end of the link.
* @s_node: Hook to the supplier device's list of links to consumers.
* @consumer: The device on the consumer end of the link.
* @c_node: Hook to the consumer device's list of links to suppliers.
* @status: The state of the link (with respect to the presence of drivers).
* @flags: Link flags.
* @rpm_active: Whether or not the consumer device is runtime-PM-active.
* @kref: Count repeated addition of the same link.
driver core: Functional dependencies tracking support Currently, there is a problem with taking functional dependencies between devices into account. What I mean by a "functional dependency" is when the driver of device B needs device A to be functional and (generally) its driver to be present in order to work properly. This has certain consequences for power management (suspend/resume and runtime PM ordering) and shutdown ordering of these devices. In general, it also implies that the driver of A needs to be working for B to be probed successfully and it cannot be unbound from the device before the B's driver. Support for representing those functional dependencies between devices is added here to allow the driver core to track them and act on them in certain cases where applicable. The argument for doing that in the driver core is that there are quite a few distinct use cases involving device dependencies, they are relatively hard to get right in a driver (if one wants to address all of them properly) and it only gets worse if multiplied by the number of drivers potentially needing to do it. Morever, at least one case (asynchronous system suspend/resume) cannot be handled in a single driver at all, because it requires the driver of A to wait for B to suspend (during system suspend) and the driver of B to wait for A to resume (during system resume). For this reason, represent dependencies between devices as "links", with the help of struct device_link objects each containing pointers to the "linked" devices, a list node for each of them, status information, flags, and an RCU head for synchronization. Also add two new list heads, representing the lists of links to the devices that depend on the given one (consumers) and to the devices depended on by it (suppliers), and a "driver presence status" field (needed for figuring out initial states of device links) to struct device. The entire data structure consisting of all of the lists of link objects for all devices is protected by a mutex (for link object addition/removal and for list walks during device driver probing and removal) and by SRCU (for list walking in other case that will be introduced by subsequent change sets). If CONFIG_SRCU is not selected, however, an rwsem is used for protecting the entire data structure. In addition, each link object has an internal status field whose value reflects whether or not drivers are bound to the devices pointed to by the link or probing/removal of their drivers is in progress etc. That field is only modified under the device links mutex, but it may be read outside of it in some cases (introduced by subsequent change sets), so modifications of it are annotated with WRITE_ONCE(). New links are added by calling device_link_add() which takes three arguments: pointers to the devices in question and flags. In particular, if DL_FLAG_STATELESS is set in the flags, the link status is not to be taken into account for this link and the driver core will not manage it. In turn, if DL_FLAG_AUTOREMOVE is set in the flags, the driver core will remove the link automatically when the consumer device driver unbinds from it. One of the actions carried out by device_link_add() is to reorder the lists used for device shutdown and system suspend/resume to put the consumer device along with all of its children and all of its consumers (and so on, recursively) to the ends of those lists in order to ensure the right ordering between all of the supplier and consumer devices. For this reason, it is not possible to create a link between two devices if the would-be supplier device already depends on the would-be consumer device as either a direct descendant of it or a consumer of one of its direct descendants or one of its consumers and so on. There are two types of link objects, persistent and non-persistent. The persistent ones stay around until one of the target devices is deleted, while the non-persistent ones are removed automatically when the consumer driver unbinds from its device (ie. they are assumed to be valid only as long as the consumer device has a driver bound to it). Persistent links are created by default and non-persistent links are created when the DL_FLAG_AUTOREMOVE flag is passed to device_link_add(). Both persistent and non-persistent device links can be deleted with an explicit call to device_link_del(). Links created without the DL_FLAG_STATELESS flag set are managed by the driver core using a simple state machine. There are 5 states each link can be in: DORMANT (unused), AVAILABLE (the supplier driver is present and functional), CONSUMER_PROBE (the consumer driver is probing), ACTIVE (both supplier and consumer drivers are present and functional), and SUPPLIER_UNBIND (the supplier driver is unbinding). The driver core updates the link state automatically depending on what happens to the linked devices and for each link state specific actions are taken in addition to that. For example, if the supplier driver unbinds from its device, the driver core will also unbind the drivers of all of its consumers automatically under the assumption that they cannot function properly without the supplier. Analogously, the driver core will only allow the consumer driver to bind to its device if the supplier driver is present and functional (ie. the link is in the AVAILABLE state). If that's not the case, it will rely on the existing deferred probing mechanism to wait for the supplier driver to become available. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-30 23:32:16 +07:00
* @rcu_head: An RCU head to use for deferred execution of SRCU callbacks.
* @supplier_preactivated: Supplier has been made active before consumer probe.
driver core: Functional dependencies tracking support Currently, there is a problem with taking functional dependencies between devices into account. What I mean by a "functional dependency" is when the driver of device B needs device A to be functional and (generally) its driver to be present in order to work properly. This has certain consequences for power management (suspend/resume and runtime PM ordering) and shutdown ordering of these devices. In general, it also implies that the driver of A needs to be working for B to be probed successfully and it cannot be unbound from the device before the B's driver. Support for representing those functional dependencies between devices is added here to allow the driver core to track them and act on them in certain cases where applicable. The argument for doing that in the driver core is that there are quite a few distinct use cases involving device dependencies, they are relatively hard to get right in a driver (if one wants to address all of them properly) and it only gets worse if multiplied by the number of drivers potentially needing to do it. Morever, at least one case (asynchronous system suspend/resume) cannot be handled in a single driver at all, because it requires the driver of A to wait for B to suspend (during system suspend) and the driver of B to wait for A to resume (during system resume). For this reason, represent dependencies between devices as "links", with the help of struct device_link objects each containing pointers to the "linked" devices, a list node for each of them, status information, flags, and an RCU head for synchronization. Also add two new list heads, representing the lists of links to the devices that depend on the given one (consumers) and to the devices depended on by it (suppliers), and a "driver presence status" field (needed for figuring out initial states of device links) to struct device. The entire data structure consisting of all of the lists of link objects for all devices is protected by a mutex (for link object addition/removal and for list walks during device driver probing and removal) and by SRCU (for list walking in other case that will be introduced by subsequent change sets). If CONFIG_SRCU is not selected, however, an rwsem is used for protecting the entire data structure. In addition, each link object has an internal status field whose value reflects whether or not drivers are bound to the devices pointed to by the link or probing/removal of their drivers is in progress etc. That field is only modified under the device links mutex, but it may be read outside of it in some cases (introduced by subsequent change sets), so modifications of it are annotated with WRITE_ONCE(). New links are added by calling device_link_add() which takes three arguments: pointers to the devices in question and flags. In particular, if DL_FLAG_STATELESS is set in the flags, the link status is not to be taken into account for this link and the driver core will not manage it. In turn, if DL_FLAG_AUTOREMOVE is set in the flags, the driver core will remove the link automatically when the consumer device driver unbinds from it. One of the actions carried out by device_link_add() is to reorder the lists used for device shutdown and system suspend/resume to put the consumer device along with all of its children and all of its consumers (and so on, recursively) to the ends of those lists in order to ensure the right ordering between all of the supplier and consumer devices. For this reason, it is not possible to create a link between two devices if the would-be supplier device already depends on the would-be consumer device as either a direct descendant of it or a consumer of one of its direct descendants or one of its consumers and so on. There are two types of link objects, persistent and non-persistent. The persistent ones stay around until one of the target devices is deleted, while the non-persistent ones are removed automatically when the consumer driver unbinds from its device (ie. they are assumed to be valid only as long as the consumer device has a driver bound to it). Persistent links are created by default and non-persistent links are created when the DL_FLAG_AUTOREMOVE flag is passed to device_link_add(). Both persistent and non-persistent device links can be deleted with an explicit call to device_link_del(). Links created without the DL_FLAG_STATELESS flag set are managed by the driver core using a simple state machine. There are 5 states each link can be in: DORMANT (unused), AVAILABLE (the supplier driver is present and functional), CONSUMER_PROBE (the consumer driver is probing), ACTIVE (both supplier and consumer drivers are present and functional), and SUPPLIER_UNBIND (the supplier driver is unbinding). The driver core updates the link state automatically depending on what happens to the linked devices and for each link state specific actions are taken in addition to that. For example, if the supplier driver unbinds from its device, the driver core will also unbind the drivers of all of its consumers automatically under the assumption that they cannot function properly without the supplier. Analogously, the driver core will only allow the consumer driver to bind to its device if the supplier driver is present and functional (ie. the link is in the AVAILABLE state). If that's not the case, it will rely on the existing deferred probing mechanism to wait for the supplier driver to become available. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-30 23:32:16 +07:00
*/
struct device_link {
struct device *supplier;
struct list_head s_node;
struct device *consumer;
struct list_head c_node;
enum device_link_state status;
u32 flags;
driver core: Fix handling of runtime PM flags in device_link_add() After commit ead18c23c263 ("driver core: Introduce device links reference counting"), if there is a link between the given supplier and the given consumer already, device_link_add() will refcount it and return it unconditionally without updating its flags. It is possible, however, that the second (or any subsequent) caller of device_link_add() for the same consumer-supplier pair will pass DL_FLAG_PM_RUNTIME, possibly along with DL_FLAG_RPM_ACTIVE, in flags to it and the existing link may not behave as expected then. First, if DL_FLAG_PM_RUNTIME is not set in the existing link's flags at all, it needs to be set like during the original initialization of the link. Second, if DL_FLAG_RPM_ACTIVE is passed to device_link_add() in flags (in addition to DL_FLAG_PM_RUNTIME), the existing link should to be updated to reflect the "active" runtime PM configuration of the consumer-supplier pair and extra care must be taken here to avoid possible destructive races with runtime PM of the consumer. To that end, redefine the rpm_active field in struct device_link as a refcount, initialize it to 1 and make rpm_resume() (for the consumer) and device_link_add() increment it whenever they acquire a runtime PM reference on the supplier device. Accordingly, make rpm_suspend() (for the consumer) and pm_runtime_clean_up_links() decrement it and drop runtime PM references to the supplier device in a loop until rpm_active becones 1 again. Fixes: ead18c23c263 ("driver core: Introduce device links reference counting") Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-01 07:49:14 +07:00
refcount_t rpm_active;
struct kref kref;
driver core: Functional dependencies tracking support Currently, there is a problem with taking functional dependencies between devices into account. What I mean by a "functional dependency" is when the driver of device B needs device A to be functional and (generally) its driver to be present in order to work properly. This has certain consequences for power management (suspend/resume and runtime PM ordering) and shutdown ordering of these devices. In general, it also implies that the driver of A needs to be working for B to be probed successfully and it cannot be unbound from the device before the B's driver. Support for representing those functional dependencies between devices is added here to allow the driver core to track them and act on them in certain cases where applicable. The argument for doing that in the driver core is that there are quite a few distinct use cases involving device dependencies, they are relatively hard to get right in a driver (if one wants to address all of them properly) and it only gets worse if multiplied by the number of drivers potentially needing to do it. Morever, at least one case (asynchronous system suspend/resume) cannot be handled in a single driver at all, because it requires the driver of A to wait for B to suspend (during system suspend) and the driver of B to wait for A to resume (during system resume). For this reason, represent dependencies between devices as "links", with the help of struct device_link objects each containing pointers to the "linked" devices, a list node for each of them, status information, flags, and an RCU head for synchronization. Also add two new list heads, representing the lists of links to the devices that depend on the given one (consumers) and to the devices depended on by it (suppliers), and a "driver presence status" field (needed for figuring out initial states of device links) to struct device. The entire data structure consisting of all of the lists of link objects for all devices is protected by a mutex (for link object addition/removal and for list walks during device driver probing and removal) and by SRCU (for list walking in other case that will be introduced by subsequent change sets). If CONFIG_SRCU is not selected, however, an rwsem is used for protecting the entire data structure. In addition, each link object has an internal status field whose value reflects whether or not drivers are bound to the devices pointed to by the link or probing/removal of their drivers is in progress etc. That field is only modified under the device links mutex, but it may be read outside of it in some cases (introduced by subsequent change sets), so modifications of it are annotated with WRITE_ONCE(). New links are added by calling device_link_add() which takes three arguments: pointers to the devices in question and flags. In particular, if DL_FLAG_STATELESS is set in the flags, the link status is not to be taken into account for this link and the driver core will not manage it. In turn, if DL_FLAG_AUTOREMOVE is set in the flags, the driver core will remove the link automatically when the consumer device driver unbinds from it. One of the actions carried out by device_link_add() is to reorder the lists used for device shutdown and system suspend/resume to put the consumer device along with all of its children and all of its consumers (and so on, recursively) to the ends of those lists in order to ensure the right ordering between all of the supplier and consumer devices. For this reason, it is not possible to create a link between two devices if the would-be supplier device already depends on the would-be consumer device as either a direct descendant of it or a consumer of one of its direct descendants or one of its consumers and so on. There are two types of link objects, persistent and non-persistent. The persistent ones stay around until one of the target devices is deleted, while the non-persistent ones are removed automatically when the consumer driver unbinds from its device (ie. they are assumed to be valid only as long as the consumer device has a driver bound to it). Persistent links are created by default and non-persistent links are created when the DL_FLAG_AUTOREMOVE flag is passed to device_link_add(). Both persistent and non-persistent device links can be deleted with an explicit call to device_link_del(). Links created without the DL_FLAG_STATELESS flag set are managed by the driver core using a simple state machine. There are 5 states each link can be in: DORMANT (unused), AVAILABLE (the supplier driver is present and functional), CONSUMER_PROBE (the consumer driver is probing), ACTIVE (both supplier and consumer drivers are present and functional), and SUPPLIER_UNBIND (the supplier driver is unbinding). The driver core updates the link state automatically depending on what happens to the linked devices and for each link state specific actions are taken in addition to that. For example, if the supplier driver unbinds from its device, the driver core will also unbind the drivers of all of its consumers automatically under the assumption that they cannot function properly without the supplier. Analogously, the driver core will only allow the consumer driver to bind to its device if the supplier driver is present and functional (ie. the link is in the AVAILABLE state). If that's not the case, it will rely on the existing deferred probing mechanism to wait for the supplier driver to become available. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-30 23:32:16 +07:00
#ifdef CONFIG_SRCU
struct rcu_head rcu_head;
#endif
driver core: Fix PM-runtime for links added during consumer probe Commit 4c06c4e6cf63 ("driver core: Fix possible supplier PM-usage counter imbalance") introduced a regression that causes suppliers to be suspended prematurely for device links added during consumer driver probe if the initial PM-runtime status of the consumer is "suspended" and the consumer is resumed after adding the link and before pm_runtime_put_suppliers() is called. In that case, pm_runtime_put_suppliers() will drop the rpm_active refcount for the link by one and (since rpm_active is equal to two after the preceding consumer resume) the supplier's PM-runtime usage counter will be decremented, which may cause the supplier to suspend even though the consumer's PM-runtime status is "active". For this reason, partially revert commit 4c06c4e6cf63 as the problem it tried to fix needs to be addressed somewhat differently, and change pm_runtime_get_suppliers() and pm_runtime_put_suppliers() so that the latter only drops rpm_active references acquired by the former. [This requires adding a new field to struct device_link, but I coulnd't find a cleaner way to address the issue that would work in all cases.] This causes pm_runtime_put_suppliers() to effectively ignore device links added during consumer probe, so device_link_add() doesn't need to worry about ensuring that suppliers will remain active after pm_runtime_put_suppliers() for links created with DL_FLAG_RPM_ACTIVE set and it only needs to bump up rpm_active by one for those links, so pm_runtime_active_link() is not necessary any more. Fixes: 4c06c4e6cf63 ("driver core: Fix possible supplier PM-usage counter imbalance") Reported-by: Jon Hunter <jonathanh@nvidia.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Tested-by: Ulf Hansson <ulf.hansson@linaro.org> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-19 23:53:26 +07:00
bool supplier_preactivated; /* Owned by consumer probe. */
driver core: Functional dependencies tracking support Currently, there is a problem with taking functional dependencies between devices into account. What I mean by a "functional dependency" is when the driver of device B needs device A to be functional and (generally) its driver to be present in order to work properly. This has certain consequences for power management (suspend/resume and runtime PM ordering) and shutdown ordering of these devices. In general, it also implies that the driver of A needs to be working for B to be probed successfully and it cannot be unbound from the device before the B's driver. Support for representing those functional dependencies between devices is added here to allow the driver core to track them and act on them in certain cases where applicable. The argument for doing that in the driver core is that there are quite a few distinct use cases involving device dependencies, they are relatively hard to get right in a driver (if one wants to address all of them properly) and it only gets worse if multiplied by the number of drivers potentially needing to do it. Morever, at least one case (asynchronous system suspend/resume) cannot be handled in a single driver at all, because it requires the driver of A to wait for B to suspend (during system suspend) and the driver of B to wait for A to resume (during system resume). For this reason, represent dependencies between devices as "links", with the help of struct device_link objects each containing pointers to the "linked" devices, a list node for each of them, status information, flags, and an RCU head for synchronization. Also add two new list heads, representing the lists of links to the devices that depend on the given one (consumers) and to the devices depended on by it (suppliers), and a "driver presence status" field (needed for figuring out initial states of device links) to struct device. The entire data structure consisting of all of the lists of link objects for all devices is protected by a mutex (for link object addition/removal and for list walks during device driver probing and removal) and by SRCU (for list walking in other case that will be introduced by subsequent change sets). If CONFIG_SRCU is not selected, however, an rwsem is used for protecting the entire data structure. In addition, each link object has an internal status field whose value reflects whether or not drivers are bound to the devices pointed to by the link or probing/removal of their drivers is in progress etc. That field is only modified under the device links mutex, but it may be read outside of it in some cases (introduced by subsequent change sets), so modifications of it are annotated with WRITE_ONCE(). New links are added by calling device_link_add() which takes three arguments: pointers to the devices in question and flags. In particular, if DL_FLAG_STATELESS is set in the flags, the link status is not to be taken into account for this link and the driver core will not manage it. In turn, if DL_FLAG_AUTOREMOVE is set in the flags, the driver core will remove the link automatically when the consumer device driver unbinds from it. One of the actions carried out by device_link_add() is to reorder the lists used for device shutdown and system suspend/resume to put the consumer device along with all of its children and all of its consumers (and so on, recursively) to the ends of those lists in order to ensure the right ordering between all of the supplier and consumer devices. For this reason, it is not possible to create a link between two devices if the would-be supplier device already depends on the would-be consumer device as either a direct descendant of it or a consumer of one of its direct descendants or one of its consumers and so on. There are two types of link objects, persistent and non-persistent. The persistent ones stay around until one of the target devices is deleted, while the non-persistent ones are removed automatically when the consumer driver unbinds from its device (ie. they are assumed to be valid only as long as the consumer device has a driver bound to it). Persistent links are created by default and non-persistent links are created when the DL_FLAG_AUTOREMOVE flag is passed to device_link_add(). Both persistent and non-persistent device links can be deleted with an explicit call to device_link_del(). Links created without the DL_FLAG_STATELESS flag set are managed by the driver core using a simple state machine. There are 5 states each link can be in: DORMANT (unused), AVAILABLE (the supplier driver is present and functional), CONSUMER_PROBE (the consumer driver is probing), ACTIVE (both supplier and consumer drivers are present and functional), and SUPPLIER_UNBIND (the supplier driver is unbinding). The driver core updates the link state automatically depending on what happens to the linked devices and for each link state specific actions are taken in addition to that. For example, if the supplier driver unbinds from its device, the driver core will also unbind the drivers of all of its consumers automatically under the assumption that they cannot function properly without the supplier. Analogously, the driver core will only allow the consumer driver to bind to its device if the supplier driver is present and functional (ie. the link is in the AVAILABLE state). If that's not the case, it will rely on the existing deferred probing mechanism to wait for the supplier driver to become available. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-30 23:32:16 +07:00
};
/**
* enum dl_dev_state - Device driver presence tracking information.
* @DL_DEV_NO_DRIVER: There is no driver attached to the device.
* @DL_DEV_PROBING: A driver is probing.
* @DL_DEV_DRIVER_BOUND: The driver has been bound to the device.
* @DL_DEV_UNBINDING: The driver is unbinding from the device.
*/
enum dl_dev_state {
DL_DEV_NO_DRIVER = 0,
DL_DEV_PROBING,
DL_DEV_DRIVER_BOUND,
DL_DEV_UNBINDING,
};
/**
* struct dev_links_info - Device data related to device links.
* @suppliers: List of links to supplier devices.
* @consumers: List of links to consumer devices.
* @needs_suppliers: Hook to global list of devices waiting for suppliers.
driver core: Add sync_state driver/bus callback This sync_state driver/bus callback is called once all the consumers of a supplier have probed successfully. This allows the supplier device's driver/bus to sync the supplier device's state to the software state with the guarantee that all the consumers are actively managing the resources provided by the supplier device. To maintain backwards compatibility and ease transition from existing frameworks and resource cleanup schemes, late_initcall_sync is the earliest when the sync_state callback might be called. There is no upper bound on the time by which the sync_state callback has to be called. This is because if a consumer device never probes, the supplier has to maintain its resources in the state left by the bootloader. For example, if the bootloader leaves the display backlight at a fixed voltage and the backlight driver is never probed, you don't want the backlight to ever be turned off after boot up. Also, when multiple devices are added after kernel init, some suppliers could be added before their consumer devices get added. In these instances, the supplier devices could get their sync_state callback called right after they probe because the consumers devices haven't had a chance to create device links to the suppliers. To handle this correctly, this change also provides APIs to pause/resume sync state callbacks so that when multiple devices are added, their sync_state callback evaluation can be postponed to happen after all of them are added. kbuild test robot reported missing documentation for device.state_synced Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Saravana Kannan <saravanak@google.com> Link: https://lore.kernel.org/r/20190904211126.47518-5-saravanak@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-05 04:11:23 +07:00
* @defer_sync: Hook to global list of devices that have deferred sync_state.
* @need_for_probe: If needs_suppliers is on a list, this indicates if the
* suppliers are needed for probe or not.
driver core: Functional dependencies tracking support Currently, there is a problem with taking functional dependencies between devices into account. What I mean by a "functional dependency" is when the driver of device B needs device A to be functional and (generally) its driver to be present in order to work properly. This has certain consequences for power management (suspend/resume and runtime PM ordering) and shutdown ordering of these devices. In general, it also implies that the driver of A needs to be working for B to be probed successfully and it cannot be unbound from the device before the B's driver. Support for representing those functional dependencies between devices is added here to allow the driver core to track them and act on them in certain cases where applicable. The argument for doing that in the driver core is that there are quite a few distinct use cases involving device dependencies, they are relatively hard to get right in a driver (if one wants to address all of them properly) and it only gets worse if multiplied by the number of drivers potentially needing to do it. Morever, at least one case (asynchronous system suspend/resume) cannot be handled in a single driver at all, because it requires the driver of A to wait for B to suspend (during system suspend) and the driver of B to wait for A to resume (during system resume). For this reason, represent dependencies between devices as "links", with the help of struct device_link objects each containing pointers to the "linked" devices, a list node for each of them, status information, flags, and an RCU head for synchronization. Also add two new list heads, representing the lists of links to the devices that depend on the given one (consumers) and to the devices depended on by it (suppliers), and a "driver presence status" field (needed for figuring out initial states of device links) to struct device. The entire data structure consisting of all of the lists of link objects for all devices is protected by a mutex (for link object addition/removal and for list walks during device driver probing and removal) and by SRCU (for list walking in other case that will be introduced by subsequent change sets). If CONFIG_SRCU is not selected, however, an rwsem is used for protecting the entire data structure. In addition, each link object has an internal status field whose value reflects whether or not drivers are bound to the devices pointed to by the link or probing/removal of their drivers is in progress etc. That field is only modified under the device links mutex, but it may be read outside of it in some cases (introduced by subsequent change sets), so modifications of it are annotated with WRITE_ONCE(). New links are added by calling device_link_add() which takes three arguments: pointers to the devices in question and flags. In particular, if DL_FLAG_STATELESS is set in the flags, the link status is not to be taken into account for this link and the driver core will not manage it. In turn, if DL_FLAG_AUTOREMOVE is set in the flags, the driver core will remove the link automatically when the consumer device driver unbinds from it. One of the actions carried out by device_link_add() is to reorder the lists used for device shutdown and system suspend/resume to put the consumer device along with all of its children and all of its consumers (and so on, recursively) to the ends of those lists in order to ensure the right ordering between all of the supplier and consumer devices. For this reason, it is not possible to create a link between two devices if the would-be supplier device already depends on the would-be consumer device as either a direct descendant of it or a consumer of one of its direct descendants or one of its consumers and so on. There are two types of link objects, persistent and non-persistent. The persistent ones stay around until one of the target devices is deleted, while the non-persistent ones are removed automatically when the consumer driver unbinds from its device (ie. they are assumed to be valid only as long as the consumer device has a driver bound to it). Persistent links are created by default and non-persistent links are created when the DL_FLAG_AUTOREMOVE flag is passed to device_link_add(). Both persistent and non-persistent device links can be deleted with an explicit call to device_link_del(). Links created without the DL_FLAG_STATELESS flag set are managed by the driver core using a simple state machine. There are 5 states each link can be in: DORMANT (unused), AVAILABLE (the supplier driver is present and functional), CONSUMER_PROBE (the consumer driver is probing), ACTIVE (both supplier and consumer drivers are present and functional), and SUPPLIER_UNBIND (the supplier driver is unbinding). The driver core updates the link state automatically depending on what happens to the linked devices and for each link state specific actions are taken in addition to that. For example, if the supplier driver unbinds from its device, the driver core will also unbind the drivers of all of its consumers automatically under the assumption that they cannot function properly without the supplier. Analogously, the driver core will only allow the consumer driver to bind to its device if the supplier driver is present and functional (ie. the link is in the AVAILABLE state). If that's not the case, it will rely on the existing deferred probing mechanism to wait for the supplier driver to become available. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-30 23:32:16 +07:00
* @status: Driver status information.
*/
struct dev_links_info {
struct list_head suppliers;
struct list_head consumers;
struct list_head needs_suppliers;
driver core: Add sync_state driver/bus callback This sync_state driver/bus callback is called once all the consumers of a supplier have probed successfully. This allows the supplier device's driver/bus to sync the supplier device's state to the software state with the guarantee that all the consumers are actively managing the resources provided by the supplier device. To maintain backwards compatibility and ease transition from existing frameworks and resource cleanup schemes, late_initcall_sync is the earliest when the sync_state callback might be called. There is no upper bound on the time by which the sync_state callback has to be called. This is because if a consumer device never probes, the supplier has to maintain its resources in the state left by the bootloader. For example, if the bootloader leaves the display backlight at a fixed voltage and the backlight driver is never probed, you don't want the backlight to ever be turned off after boot up. Also, when multiple devices are added after kernel init, some suppliers could be added before their consumer devices get added. In these instances, the supplier devices could get their sync_state callback called right after they probe because the consumers devices haven't had a chance to create device links to the suppliers. To handle this correctly, this change also provides APIs to pause/resume sync state callbacks so that when multiple devices are added, their sync_state callback evaluation can be postponed to happen after all of them are added. kbuild test robot reported missing documentation for device.state_synced Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Saravana Kannan <saravanak@google.com> Link: https://lore.kernel.org/r/20190904211126.47518-5-saravanak@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-05 04:11:23 +07:00
struct list_head defer_sync;
bool need_for_probe;
driver core: Functional dependencies tracking support Currently, there is a problem with taking functional dependencies between devices into account. What I mean by a "functional dependency" is when the driver of device B needs device A to be functional and (generally) its driver to be present in order to work properly. This has certain consequences for power management (suspend/resume and runtime PM ordering) and shutdown ordering of these devices. In general, it also implies that the driver of A needs to be working for B to be probed successfully and it cannot be unbound from the device before the B's driver. Support for representing those functional dependencies between devices is added here to allow the driver core to track them and act on them in certain cases where applicable. The argument for doing that in the driver core is that there are quite a few distinct use cases involving device dependencies, they are relatively hard to get right in a driver (if one wants to address all of them properly) and it only gets worse if multiplied by the number of drivers potentially needing to do it. Morever, at least one case (asynchronous system suspend/resume) cannot be handled in a single driver at all, because it requires the driver of A to wait for B to suspend (during system suspend) and the driver of B to wait for A to resume (during system resume). For this reason, represent dependencies between devices as "links", with the help of struct device_link objects each containing pointers to the "linked" devices, a list node for each of them, status information, flags, and an RCU head for synchronization. Also add two new list heads, representing the lists of links to the devices that depend on the given one (consumers) and to the devices depended on by it (suppliers), and a "driver presence status" field (needed for figuring out initial states of device links) to struct device. The entire data structure consisting of all of the lists of link objects for all devices is protected by a mutex (for link object addition/removal and for list walks during device driver probing and removal) and by SRCU (for list walking in other case that will be introduced by subsequent change sets). If CONFIG_SRCU is not selected, however, an rwsem is used for protecting the entire data structure. In addition, each link object has an internal status field whose value reflects whether or not drivers are bound to the devices pointed to by the link or probing/removal of their drivers is in progress etc. That field is only modified under the device links mutex, but it may be read outside of it in some cases (introduced by subsequent change sets), so modifications of it are annotated with WRITE_ONCE(). New links are added by calling device_link_add() which takes three arguments: pointers to the devices in question and flags. In particular, if DL_FLAG_STATELESS is set in the flags, the link status is not to be taken into account for this link and the driver core will not manage it. In turn, if DL_FLAG_AUTOREMOVE is set in the flags, the driver core will remove the link automatically when the consumer device driver unbinds from it. One of the actions carried out by device_link_add() is to reorder the lists used for device shutdown and system suspend/resume to put the consumer device along with all of its children and all of its consumers (and so on, recursively) to the ends of those lists in order to ensure the right ordering between all of the supplier and consumer devices. For this reason, it is not possible to create a link between two devices if the would-be supplier device already depends on the would-be consumer device as either a direct descendant of it or a consumer of one of its direct descendants or one of its consumers and so on. There are two types of link objects, persistent and non-persistent. The persistent ones stay around until one of the target devices is deleted, while the non-persistent ones are removed automatically when the consumer driver unbinds from its device (ie. they are assumed to be valid only as long as the consumer device has a driver bound to it). Persistent links are created by default and non-persistent links are created when the DL_FLAG_AUTOREMOVE flag is passed to device_link_add(). Both persistent and non-persistent device links can be deleted with an explicit call to device_link_del(). Links created without the DL_FLAG_STATELESS flag set are managed by the driver core using a simple state machine. There are 5 states each link can be in: DORMANT (unused), AVAILABLE (the supplier driver is present and functional), CONSUMER_PROBE (the consumer driver is probing), ACTIVE (both supplier and consumer drivers are present and functional), and SUPPLIER_UNBIND (the supplier driver is unbinding). The driver core updates the link state automatically depending on what happens to the linked devices and for each link state specific actions are taken in addition to that. For example, if the supplier driver unbinds from its device, the driver core will also unbind the drivers of all of its consumers automatically under the assumption that they cannot function properly without the supplier. Analogously, the driver core will only allow the consumer driver to bind to its device if the supplier driver is present and functional (ie. the link is in the AVAILABLE state). If that's not the case, it will rely on the existing deferred probing mechanism to wait for the supplier driver to become available. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-30 23:32:16 +07:00
enum dl_dev_state status;
};
/**
* struct device - The basic device structure
* @parent: The device's "parent" device, the device to which it is attached.
* In most cases, a parent device is some sort of bus or host
* controller. If parent is NULL, the device, is a top-level device,
* which is not usually what you want.
* @p: Holds the private data of the driver core portions of the device.
* See the comment of the struct device_private for detail.
* @kobj: A top-level, abstract class from which other classes are derived.
* @init_name: Initial name of the device.
* @type: The type of device.
* This identifies the device type and carries type-specific
* information.
* @mutex: Mutex to synchronize calls to its driver.
driver-core, libnvdimm: Let device subsystems add local lockdep coverage For good reason, the standard device_lock() is marked lockdep_set_novalidate_class() because there is simply no sane way to describe the myriad ways the device_lock() ordered with other locks. However, that leaves subsystems that know their own local device_lock() ordering rules to find lock ordering mistakes manually. Instead, introduce an optional / additional lockdep-enabled lock that a subsystem can acquire in all the same paths that the device_lock() is acquired. A conversion of the NFIT driver and NVDIMM subsystem to a lockdep-validate device_lock() scheme is included. The debug_nvdimm_lock() implementation implements the correct lock-class and stacking order for the libnvdimm device topology hierarchy. Yes, this is a hack, but hopefully it is a useful hack for other subsystems device_lock() debug sessions. Quoting Greg: "Yeah, it feels a bit hacky but it's really up to a subsystem to mess up using it as much as anything else, so user beware :) I don't object to it if it makes things easier for you to debug." Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Link: https://lore.kernel.org/r/156341210661.292348.7014034644265455704.stgit@dwillia2-desk3.amr.corp.intel.com
2019-07-18 08:08:26 +07:00
* @lockdep_mutex: An optional debug lock that a subsystem can use as a
* peer lock to gain localized lockdep coverage of the device_lock.
* @bus: Type of bus device is on.
* @driver: Which driver has allocated this
* @platform_data: Platform data specific to the device.
* Example: For devices on custom boards, as typical of embedded
* and SOC based hardware, Linux often uses platform_data to point
* to board-specific structures describing devices and how they
* are wired. That can include what ports are available, chip
* variants, which GPIO pins act in what additional roles, and so
* on. This shrinks the "Board Support Packages" (BSPs) and
* minimizes board-specific #ifdefs in drivers.
* @driver_data: Private pointer for driver specific info.
* @links: Links to suppliers and consumers of this device.
* @power: For device power management.
* See Documentation/driver-api/pm/devices.rst for details.
* @pm_domain: Provide callbacks that are executed during system suspend,
* hibernation, system resume and during runtime PM transitions
* along with subsystem-level and driver-level callbacks.
drivers/pinctrl: grab default handles from device core This makes the device core auto-grab the pinctrl handle and set the "default" (PINCTRL_STATE_DEFAULT) state for every device that is present in the device model right before probe. This will account for the lion's share of embedded silicon devcies. A modification of the semantics for pinctrl_get() is also done: previously if the pinctrl handle for a certain device was already taken, the pinctrl core would return an error. Now, since the core may have already default-grabbed the handle and set its state to "default", if the handle was already taken, this will be disregarded and the located, previously instanitated handle will be returned to the caller. This way all code in drivers explicitly requesting their pinctrl handlers will still be functional, and drivers that want to explicitly retrieve and switch their handles can still do that. But if the desired functionality is just boilerplate of this type in the probe() function: struct pinctrl *p; p = devm_pinctrl_get_select_default(&dev); if (IS_ERR(p)) { if (PTR_ERR(p) == -EPROBE_DEFER) return -EPROBE_DEFER; dev_warn(&dev, "no pinctrl handle\n"); } The discussion began with the addition of such boilerplate to the omap4 keypad driver: http://marc.info/?l=linux-input&m=135091157719300&w=2 A previous approach using notifiers was discussed: http://marc.info/?l=linux-kernel&m=135263661110528&w=2 This failed because it could not handle deferred probes. This patch alone does not solve the entire dilemma faced: whether code should be distributed into the drivers or if it should be centralized to e.g. a PM domain. But it solves the immediate issue of the addition of boilerplate to a lot of drivers that just want to grab the default state. As mentioned, they can later explicitly retrieve the handle and set different states, and this could as well be done by e.g. PM domains as it is only related to a certain struct device * pointer. ChangeLog v4->v5 (Stephen): - Simplified the devicecore grab code. - Deleted a piece of documentation recommending that pins be mapped to a device rather than hogged. ChangeLog v3->v4 (Linus): - Drop overzealous NULL checks. - Move kref initialization to pinctrl_create(). - Seeking Tested-by from Stephen Warren so we do not disturb the Tegra platform. - Seeking ACK on this from Greg (and others who like it) so I can merge it through the pinctrl subsystem. ChangeLog v2->v3 (Linus): - Abstain from using IS_ERR_OR_NULL() in the driver core, Russell recently sent a patch to remove it. Handle the NULL case explicitly even though it's a bogus case. - Make sure we handle probe deferral correctly in the device core file. devm_kfree() the container on error so we don't waste memory for devices without pinctrl handles. - Introduce reference counting into the pinctrl core using <linux/kref.h> so that we don't release pinctrl handles that have been obtained for two or more places. ChangeLog v1->v2 (Linus): - Only store a pointer in the device struct, and only allocate this if it's really used by the device. Cc: Felipe Balbi <balbi@ti.com> Cc: Benoit Cousson <b-cousson@ti.com> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Cc: Mitch Bradley <wmb@firmworks.com> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Cc: Rickard Andersson <rickard.andersson@stericsson.com> Cc: Russell King <linux@arm.linux.org.uk> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> [swarren: fixed and simplified error-handling in pinctrl_bind_pins(), to correctly handle deferred probe. Removed admonition from docs not to use pinctrl hogs for devices] Signed-off-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2013-01-23 00:56:14 +07:00
* @pins: For device pin management.
* See Documentation/driver-api/pinctl.rst for details.
* @msi_list: Hosts MSI descriptors
* @msi_domain: The generic MSI domain this device is using.
* @numa_node: NUMA node this device is close to.
* @dma_ops: DMA mapping operations for this device.
* @dma_mask: Dma mask (if dma'ble device).
* @coherent_dma_mask: Like dma_mask, but for alloc_coherent mapping as not all
* hardware supports 64-bit addresses for consistent allocations
* such descriptors.
* @bus_dma_limit: Limit of an upstream bridge or bus which imposes a smaller
* DMA limit than the device itself supports.
* @dma_pfn_offset: offset of DMA memory range relatively of RAM
* @dma_parms: A low level driver may set these to teach IOMMU code about
* segment limitations.
* @dma_pools: Dma pools (if dma'ble device).
* @dma_mem: Internal for coherent mem override.
* @cma_area: Contiguous memory area for dma allocations
* @archdata: For arch-specific additions.
* @of_node: Associated device tree node.
* @fwnode: Associated device node supplied by platform firmware.
* @devt: For creating the sysfs "dev".
* @id: device instance
* @devres_lock: Spinlock to protect the resource of the device.
* @devres_head: The resources list of the device.
* @knode_class: The node used to add the device to the class list.
* @class: The class of the device.
* @groups: Optional attribute groups.
* @release: Callback to free the device after all references have
* gone away. This should be set by the allocator of the
* device (i.e. the bus driver that discovered the device).
* @iommu_group: IOMMU group the device belongs to.
* @iommu: Per device generic IOMMU runtime data
*
Driver core: Add offline/online device operations In some cases, graceful hot-removal of devices is not possible, although in principle the devices in question support hotplug. For example, that may happen for the last CPU in the system or for memory modules holding kernel memory. In those cases it is nice to be able to check if the given device can be gracefully hot-removed before triggering a removal procedure that cannot be aborted or reversed. Unfortunately, however, the kernel currently doesn't provide any support for that. To address that deficiency, introduce support for offline and online operations that can be performed on devices, respectively, before a hot-removal and in case when it is necessary (or convenient) to put a device back online after a successful offline (that has not been followed by removal). The idea is that the offline will fail whenever the given device cannot be gracefully removed from the system and it will not be allowed to use the device after a successful offline (until a subsequent online) in analogy with the existing CPU offline/online mechanism. For now, the offline and online operations are introduced at the bus type level, as that should be sufficient for the most urgent use cases (CPUs and memory modules). In the future, however, the approach may be extended to cover some more complicated device offline/online scenarios involving device drivers etc. The lock_device_hotplug() and unlock_device_hotplug() functions are introduced because subsequent patches need to put larger pieces of code under device_hotplug_lock to prevent race conditions between device offline and removal from happening. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Toshi Kani <toshi.kani@hp.com>
2013-05-03 03:15:29 +07:00
* @offline_disabled: If set, the device is permanently online.
* @offline: Set after successful invocation of bus type's .offline().
driver core: add helper to reuse a device-tree node Add a helper function to be used when reusing the device-tree node of another device. It is fairly common for drivers to reuse the device-tree node of a parent (or other ancestor) device when creating class or bus devices (e.g. gpio chips, i2c adapters, iio chips, spi masters, serdev, phys, usb root hubs). But reusing a device-tree node may cause problems if the new device is later probed as for example driver core would currently attempt to reinitialise an already active associated pinmux configuration. Other potential issues include the platform-bus code unconditionally dropping the device-tree node reference in its device destructor, reinitialisation of other bus-managed resources such as clocks, and the recently added DMA-setup in driver core. Note that for most examples above this is currently not an issue as the devices are never probed, but this is a problem for the USB bus which has recently gained device-tree support. This was discovered and worked-around in a rather ad-hoc fashion by commit dc5878abf49c ("usb: core: move root hub's device node assignment after it is added to bus") by not setting the of_node pointer until after the root-hub device has been registered. Instead we can allow devices to reuse a device-tree node by setting a flag in their struct device that can be used by core, bus and driver code to avoid resources from being over-allocated. Note that the helper also grabs an extra reference to the device node, which specifically balances the unconditional put in the platform-device destructor. Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-06 22:59:00 +07:00
* @of_node_reused: Set if the device-tree node is shared with an ancestor
* device.
driver core: Add sync_state driver/bus callback This sync_state driver/bus callback is called once all the consumers of a supplier have probed successfully. This allows the supplier device's driver/bus to sync the supplier device's state to the software state with the guarantee that all the consumers are actively managing the resources provided by the supplier device. To maintain backwards compatibility and ease transition from existing frameworks and resource cleanup schemes, late_initcall_sync is the earliest when the sync_state callback might be called. There is no upper bound on the time by which the sync_state callback has to be called. This is because if a consumer device never probes, the supplier has to maintain its resources in the state left by the bootloader. For example, if the bootloader leaves the display backlight at a fixed voltage and the backlight driver is never probed, you don't want the backlight to ever be turned off after boot up. Also, when multiple devices are added after kernel init, some suppliers could be added before their consumer devices get added. In these instances, the supplier devices could get their sync_state callback called right after they probe because the consumers devices haven't had a chance to create device links to the suppliers. To handle this correctly, this change also provides APIs to pause/resume sync state callbacks so that when multiple devices are added, their sync_state callback evaluation can be postponed to happen after all of them are added. kbuild test robot reported missing documentation for device.state_synced Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Saravana Kannan <saravanak@google.com> Link: https://lore.kernel.org/r/20190904211126.47518-5-saravanak@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-05 04:11:23 +07:00
* @state_synced: The hardware state of this device has been synced to match
* the software state of this device by calling the driver/bus
* sync_state() callback.
* @dma_coherent: this particular device is dma coherent, even if the
* architecture supports non-coherent devices.
*
* At the lowest level, every device in a Linux system is represented by an
* instance of struct device. The device structure contains the information
* that the device model core needs to model the system. Most subsystems,
* however, track additional information about the devices they host. As a
* result, it is rare for devices to be represented by bare device structures;
* instead, that structure, like kobject structures, is usually embedded within
* a higher-level representation of the device.
*/
struct device {
struct kobject kobj;
fix hotplug for legacy platform drivers We've had various reports of some legacy "probe the hardware" style platform drivers having nasty problems with hotplug support. The core issue is that those legacy drivers don't fully conform to the driver model. They assume a role that should be the responsibility of infrastructure code: creating device nodes. The "modprobe" step in hotplugging relies on drivers to have split those roles into different modules. The lack of this split causes the problems. When a driver creates nodes for devices that don't exist (sending a hotplug event), then exits (aborting one modprobe) before the "modprobe $MODALIAS" step completes (by failing, since it's in the middle of a modprobe), the result can be an endless loop of modprobe invocations ... badness. This fix uses the newish per-device flag controlling issuance of "add" events. (A previous version of this patch used a per-device "driver can hotplug" flag, which only scrubbed $MODALIAS from the environment rather than suppressing the entire hotplug event.) It also shrinks that flag to one bit, saving a word in "struct device". So the net of this patch is removing some nasty failures with legacy drivers, while retaining hotplug capability for the majority of platform drivers. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Cc: Greg KH <gregkh@suse.de> Cc: Andres Salomon <dilinger@debian.org> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 14:29:39 +07:00
struct device *parent;
struct device_private *p;
const char *init_name; /* initial name of the device */
const struct device_type *type;
struct bus_type *bus; /* type of bus device is on */
struct device_driver *driver; /* which driver has allocated this
device */
void *platform_data; /* Platform specific data, device
core doesn't touch it */
void *driver_data; /* Driver data, set and get with
dev_set_drvdata/dev_get_drvdata */
driver-core, libnvdimm: Let device subsystems add local lockdep coverage For good reason, the standard device_lock() is marked lockdep_set_novalidate_class() because there is simply no sane way to describe the myriad ways the device_lock() ordered with other locks. However, that leaves subsystems that know their own local device_lock() ordering rules to find lock ordering mistakes manually. Instead, introduce an optional / additional lockdep-enabled lock that a subsystem can acquire in all the same paths that the device_lock() is acquired. A conversion of the NFIT driver and NVDIMM subsystem to a lockdep-validate device_lock() scheme is included. The debug_nvdimm_lock() implementation implements the correct lock-class and stacking order for the libnvdimm device topology hierarchy. Yes, this is a hack, but hopefully it is a useful hack for other subsystems device_lock() debug sessions. Quoting Greg: "Yeah, it feels a bit hacky but it's really up to a subsystem to mess up using it as much as anything else, so user beware :) I don't object to it if it makes things easier for you to debug." Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Link: https://lore.kernel.org/r/156341210661.292348.7014034644265455704.stgit@dwillia2-desk3.amr.corp.intel.com
2019-07-18 08:08:26 +07:00
#ifdef CONFIG_PROVE_LOCKING
struct mutex lockdep_mutex;
#endif
struct mutex mutex; /* mutex to synchronize calls to
* its driver.
*/
driver core: Functional dependencies tracking support Currently, there is a problem with taking functional dependencies between devices into account. What I mean by a "functional dependency" is when the driver of device B needs device A to be functional and (generally) its driver to be present in order to work properly. This has certain consequences for power management (suspend/resume and runtime PM ordering) and shutdown ordering of these devices. In general, it also implies that the driver of A needs to be working for B to be probed successfully and it cannot be unbound from the device before the B's driver. Support for representing those functional dependencies between devices is added here to allow the driver core to track them and act on them in certain cases where applicable. The argument for doing that in the driver core is that there are quite a few distinct use cases involving device dependencies, they are relatively hard to get right in a driver (if one wants to address all of them properly) and it only gets worse if multiplied by the number of drivers potentially needing to do it. Morever, at least one case (asynchronous system suspend/resume) cannot be handled in a single driver at all, because it requires the driver of A to wait for B to suspend (during system suspend) and the driver of B to wait for A to resume (during system resume). For this reason, represent dependencies between devices as "links", with the help of struct device_link objects each containing pointers to the "linked" devices, a list node for each of them, status information, flags, and an RCU head for synchronization. Also add two new list heads, representing the lists of links to the devices that depend on the given one (consumers) and to the devices depended on by it (suppliers), and a "driver presence status" field (needed for figuring out initial states of device links) to struct device. The entire data structure consisting of all of the lists of link objects for all devices is protected by a mutex (for link object addition/removal and for list walks during device driver probing and removal) and by SRCU (for list walking in other case that will be introduced by subsequent change sets). If CONFIG_SRCU is not selected, however, an rwsem is used for protecting the entire data structure. In addition, each link object has an internal status field whose value reflects whether or not drivers are bound to the devices pointed to by the link or probing/removal of their drivers is in progress etc. That field is only modified under the device links mutex, but it may be read outside of it in some cases (introduced by subsequent change sets), so modifications of it are annotated with WRITE_ONCE(). New links are added by calling device_link_add() which takes three arguments: pointers to the devices in question and flags. In particular, if DL_FLAG_STATELESS is set in the flags, the link status is not to be taken into account for this link and the driver core will not manage it. In turn, if DL_FLAG_AUTOREMOVE is set in the flags, the driver core will remove the link automatically when the consumer device driver unbinds from it. One of the actions carried out by device_link_add() is to reorder the lists used for device shutdown and system suspend/resume to put the consumer device along with all of its children and all of its consumers (and so on, recursively) to the ends of those lists in order to ensure the right ordering between all of the supplier and consumer devices. For this reason, it is not possible to create a link between two devices if the would-be supplier device already depends on the would-be consumer device as either a direct descendant of it or a consumer of one of its direct descendants or one of its consumers and so on. There are two types of link objects, persistent and non-persistent. The persistent ones stay around until one of the target devices is deleted, while the non-persistent ones are removed automatically when the consumer driver unbinds from its device (ie. they are assumed to be valid only as long as the consumer device has a driver bound to it). Persistent links are created by default and non-persistent links are created when the DL_FLAG_AUTOREMOVE flag is passed to device_link_add(). Both persistent and non-persistent device links can be deleted with an explicit call to device_link_del(). Links created without the DL_FLAG_STATELESS flag set are managed by the driver core using a simple state machine. There are 5 states each link can be in: DORMANT (unused), AVAILABLE (the supplier driver is present and functional), CONSUMER_PROBE (the consumer driver is probing), ACTIVE (both supplier and consumer drivers are present and functional), and SUPPLIER_UNBIND (the supplier driver is unbinding). The driver core updates the link state automatically depending on what happens to the linked devices and for each link state specific actions are taken in addition to that. For example, if the supplier driver unbinds from its device, the driver core will also unbind the drivers of all of its consumers automatically under the assumption that they cannot function properly without the supplier. Analogously, the driver core will only allow the consumer driver to bind to its device if the supplier driver is present and functional (ie. the link is in the AVAILABLE state). If that's not the case, it will rely on the existing deferred probing mechanism to wait for the supplier driver to become available. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-30 23:32:16 +07:00
struct dev_links_info links;
struct dev_pm_info power;
struct dev_pm_domain *pm_domain;
#ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
struct irq_domain *msi_domain;
#endif
drivers/pinctrl: grab default handles from device core This makes the device core auto-grab the pinctrl handle and set the "default" (PINCTRL_STATE_DEFAULT) state for every device that is present in the device model right before probe. This will account for the lion's share of embedded silicon devcies. A modification of the semantics for pinctrl_get() is also done: previously if the pinctrl handle for a certain device was already taken, the pinctrl core would return an error. Now, since the core may have already default-grabbed the handle and set its state to "default", if the handle was already taken, this will be disregarded and the located, previously instanitated handle will be returned to the caller. This way all code in drivers explicitly requesting their pinctrl handlers will still be functional, and drivers that want to explicitly retrieve and switch their handles can still do that. But if the desired functionality is just boilerplate of this type in the probe() function: struct pinctrl *p; p = devm_pinctrl_get_select_default(&dev); if (IS_ERR(p)) { if (PTR_ERR(p) == -EPROBE_DEFER) return -EPROBE_DEFER; dev_warn(&dev, "no pinctrl handle\n"); } The discussion began with the addition of such boilerplate to the omap4 keypad driver: http://marc.info/?l=linux-input&m=135091157719300&w=2 A previous approach using notifiers was discussed: http://marc.info/?l=linux-kernel&m=135263661110528&w=2 This failed because it could not handle deferred probes. This patch alone does not solve the entire dilemma faced: whether code should be distributed into the drivers or if it should be centralized to e.g. a PM domain. But it solves the immediate issue of the addition of boilerplate to a lot of drivers that just want to grab the default state. As mentioned, they can later explicitly retrieve the handle and set different states, and this could as well be done by e.g. PM domains as it is only related to a certain struct device * pointer. ChangeLog v4->v5 (Stephen): - Simplified the devicecore grab code. - Deleted a piece of documentation recommending that pins be mapped to a device rather than hogged. ChangeLog v3->v4 (Linus): - Drop overzealous NULL checks. - Move kref initialization to pinctrl_create(). - Seeking Tested-by from Stephen Warren so we do not disturb the Tegra platform. - Seeking ACK on this from Greg (and others who like it) so I can merge it through the pinctrl subsystem. ChangeLog v2->v3 (Linus): - Abstain from using IS_ERR_OR_NULL() in the driver core, Russell recently sent a patch to remove it. Handle the NULL case explicitly even though it's a bogus case. - Make sure we handle probe deferral correctly in the device core file. devm_kfree() the container on error so we don't waste memory for devices without pinctrl handles. - Introduce reference counting into the pinctrl core using <linux/kref.h> so that we don't release pinctrl handles that have been obtained for two or more places. ChangeLog v1->v2 (Linus): - Only store a pointer in the device struct, and only allocate this if it's really used by the device. Cc: Felipe Balbi <balbi@ti.com> Cc: Benoit Cousson <b-cousson@ti.com> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Cc: Mitch Bradley <wmb@firmworks.com> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Cc: Rickard Andersson <rickard.andersson@stericsson.com> Cc: Russell King <linux@arm.linux.org.uk> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> [swarren: fixed and simplified error-handling in pinctrl_bind_pins(), to correctly handle deferred probe. Removed admonition from docs not to use pinctrl hogs for devices] Signed-off-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2013-01-23 00:56:14 +07:00
#ifdef CONFIG_PINCTRL
struct dev_pin_info *pins;
#endif
#ifdef CONFIG_GENERIC_MSI_IRQ
struct list_head msi_list;
#endif
drivers/pinctrl: grab default handles from device core This makes the device core auto-grab the pinctrl handle and set the "default" (PINCTRL_STATE_DEFAULT) state for every device that is present in the device model right before probe. This will account for the lion's share of embedded silicon devcies. A modification of the semantics for pinctrl_get() is also done: previously if the pinctrl handle for a certain device was already taken, the pinctrl core would return an error. Now, since the core may have already default-grabbed the handle and set its state to "default", if the handle was already taken, this will be disregarded and the located, previously instanitated handle will be returned to the caller. This way all code in drivers explicitly requesting their pinctrl handlers will still be functional, and drivers that want to explicitly retrieve and switch their handles can still do that. But if the desired functionality is just boilerplate of this type in the probe() function: struct pinctrl *p; p = devm_pinctrl_get_select_default(&dev); if (IS_ERR(p)) { if (PTR_ERR(p) == -EPROBE_DEFER) return -EPROBE_DEFER; dev_warn(&dev, "no pinctrl handle\n"); } The discussion began with the addition of such boilerplate to the omap4 keypad driver: http://marc.info/?l=linux-input&m=135091157719300&w=2 A previous approach using notifiers was discussed: http://marc.info/?l=linux-kernel&m=135263661110528&w=2 This failed because it could not handle deferred probes. This patch alone does not solve the entire dilemma faced: whether code should be distributed into the drivers or if it should be centralized to e.g. a PM domain. But it solves the immediate issue of the addition of boilerplate to a lot of drivers that just want to grab the default state. As mentioned, they can later explicitly retrieve the handle and set different states, and this could as well be done by e.g. PM domains as it is only related to a certain struct device * pointer. ChangeLog v4->v5 (Stephen): - Simplified the devicecore grab code. - Deleted a piece of documentation recommending that pins be mapped to a device rather than hogged. ChangeLog v3->v4 (Linus): - Drop overzealous NULL checks. - Move kref initialization to pinctrl_create(). - Seeking Tested-by from Stephen Warren so we do not disturb the Tegra platform. - Seeking ACK on this from Greg (and others who like it) so I can merge it through the pinctrl subsystem. ChangeLog v2->v3 (Linus): - Abstain from using IS_ERR_OR_NULL() in the driver core, Russell recently sent a patch to remove it. Handle the NULL case explicitly even though it's a bogus case. - Make sure we handle probe deferral correctly in the device core file. devm_kfree() the container on error so we don't waste memory for devices without pinctrl handles. - Introduce reference counting into the pinctrl core using <linux/kref.h> so that we don't release pinctrl handles that have been obtained for two or more places. ChangeLog v1->v2 (Linus): - Only store a pointer in the device struct, and only allocate this if it's really used by the device. Cc: Felipe Balbi <balbi@ti.com> Cc: Benoit Cousson <b-cousson@ti.com> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Cc: Mitch Bradley <wmb@firmworks.com> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Cc: Rickard Andersson <rickard.andersson@stericsson.com> Cc: Russell King <linux@arm.linux.org.uk> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> [swarren: fixed and simplified error-handling in pinctrl_bind_pins(), to correctly handle deferred probe. Removed admonition from docs not to use pinctrl hogs for devices] Signed-off-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2013-01-23 00:56:14 +07:00
const struct dma_map_ops *dma_ops;
u64 *dma_mask; /* dma mask (if dma'able device) */
u64 coherent_dma_mask;/* Like dma_mask, but for
alloc_coherent mappings as
not all hardware supports
64 bit addresses for consistent
allocations such descriptors. */
u64 bus_dma_limit; /* upstream dma constraint */
unsigned long dma_pfn_offset;
iommu sg merging: add device_dma_parameters structure IOMMUs merges scatter/gather segments without considering a low level driver's restrictions. The problem is that IOMMUs can't access to the limitations because they are in request_queue. This patchset introduces a new structure, device_dma_parameters, including dma information. A pointer to device_dma_parameters is added to struct device. The bus specific structures (like pci_dev) includes device_dma_parameters. Low level drivers can use dma_set_max_seg_size to tell IOMMUs about the restrictions. We can move more dma stuff in struct device (like dma_mask) to struct device_dma_parameters later (needs some cleanups before that). This includes patches for all the IOMMUs that could merge sg (x86_64, ppc, IA64, alpha, sparc64, and parisc) though only the ppc patch was tested. The patches for other IOMMUs are only compile tested. This patch: Add a new structure, device_dma_parameters, including dma information. A pointer to device_dma_parameters is added to struct device. - there are only max_segment_size and segment_boundary_mask there but we'll move more dma stuff in struct device (like dma_mask) to struct device_dma_parameters later. segment_boundary_mask is not supported yet. - new accessors for the dma parameters are added. So we can easily change where to place struct device_dma_parameters in the future. - dma_get_max_seg_size returns 64K if dma_parms in struct device isn't set up properly. 64K is the default max_segment_size in the block layer. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Acked-by: Jeff Garzik <jeff@garzik.org> Cc: James Bottomley <James.Bottomley@steeleye.com> Acked-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 13:27:55 +07:00
struct device_dma_parameters *dma_parms;
struct list_head dma_pools; /* dma pools (if dma'ble) */
#ifdef CONFIG_DMA_DECLARE_COHERENT
struct dma_coherent_mem *dma_mem; /* internal for coherent mem
override */
#endif
#ifdef CONFIG_DMA_CMA
struct cma *cma_area; /* contiguous memory area for dma
allocations */
#endif
/* arch specific additions */
struct dev_archdata archdata;
struct device_node *of_node; /* associated device tree node */
struct fwnode_handle *fwnode; /* firmware device node */
#ifdef CONFIG_NUMA
int numa_node; /* NUMA node this device is close to */
#endif
dev_t devt; /* dev_t, creates the sysfs "dev" */
u32 id; /* device instance */
spinlock_t devres_lock;
struct list_head devres_head;
struct class *class;
const struct attribute_group **groups; /* optional groups */
void (*release)(struct device *dev);
struct iommu_group *iommu_group;
struct dev_iommu *iommu;
Driver core: Add offline/online device operations In some cases, graceful hot-removal of devices is not possible, although in principle the devices in question support hotplug. For example, that may happen for the last CPU in the system or for memory modules holding kernel memory. In those cases it is nice to be able to check if the given device can be gracefully hot-removed before triggering a removal procedure that cannot be aborted or reversed. Unfortunately, however, the kernel currently doesn't provide any support for that. To address that deficiency, introduce support for offline and online operations that can be performed on devices, respectively, before a hot-removal and in case when it is necessary (or convenient) to put a device back online after a successful offline (that has not been followed by removal). The idea is that the offline will fail whenever the given device cannot be gracefully removed from the system and it will not be allowed to use the device after a successful offline (until a subsequent online) in analogy with the existing CPU offline/online mechanism. For now, the offline and online operations are introduced at the bus type level, as that should be sufficient for the most urgent use cases (CPUs and memory modules). In the future, however, the approach may be extended to cover some more complicated device offline/online scenarios involving device drivers etc. The lock_device_hotplug() and unlock_device_hotplug() functions are introduced because subsequent patches need to put larger pieces of code under device_hotplug_lock to prevent race conditions between device offline and removal from happening. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Toshi Kani <toshi.kani@hp.com>
2013-05-03 03:15:29 +07:00
bool offline_disabled:1;
bool offline:1;
driver core: add helper to reuse a device-tree node Add a helper function to be used when reusing the device-tree node of another device. It is fairly common for drivers to reuse the device-tree node of a parent (or other ancestor) device when creating class or bus devices (e.g. gpio chips, i2c adapters, iio chips, spi masters, serdev, phys, usb root hubs). But reusing a device-tree node may cause problems if the new device is later probed as for example driver core would currently attempt to reinitialise an already active associated pinmux configuration. Other potential issues include the platform-bus code unconditionally dropping the device-tree node reference in its device destructor, reinitialisation of other bus-managed resources such as clocks, and the recently added DMA-setup in driver core. Note that for most examples above this is currently not an issue as the devices are never probed, but this is a problem for the USB bus which has recently gained device-tree support. This was discovered and worked-around in a rather ad-hoc fashion by commit dc5878abf49c ("usb: core: move root hub's device node assignment after it is added to bus") by not setting the of_node pointer until after the root-hub device has been registered. Instead we can allow devices to reuse a device-tree node by setting a flag in their struct device that can be used by core, bus and driver code to avoid resources from being over-allocated. Note that the helper also grabs an extra reference to the device node, which specifically balances the unconditional put in the platform-device destructor. Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-06 22:59:00 +07:00
bool of_node_reused:1;
driver core: Add sync_state driver/bus callback This sync_state driver/bus callback is called once all the consumers of a supplier have probed successfully. This allows the supplier device's driver/bus to sync the supplier device's state to the software state with the guarantee that all the consumers are actively managing the resources provided by the supplier device. To maintain backwards compatibility and ease transition from existing frameworks and resource cleanup schemes, late_initcall_sync is the earliest when the sync_state callback might be called. There is no upper bound on the time by which the sync_state callback has to be called. This is because if a consumer device never probes, the supplier has to maintain its resources in the state left by the bootloader. For example, if the bootloader leaves the display backlight at a fixed voltage and the backlight driver is never probed, you don't want the backlight to ever be turned off after boot up. Also, when multiple devices are added after kernel init, some suppliers could be added before their consumer devices get added. In these instances, the supplier devices could get their sync_state callback called right after they probe because the consumers devices haven't had a chance to create device links to the suppliers. To handle this correctly, this change also provides APIs to pause/resume sync state callbacks so that when multiple devices are added, their sync_state callback evaluation can be postponed to happen after all of them are added. kbuild test robot reported missing documentation for device.state_synced Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Saravana Kannan <saravanak@google.com> Link: https://lore.kernel.org/r/20190904211126.47518-5-saravanak@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-05 04:11:23 +07:00
bool state_synced:1;
#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
bool dma_coherent:1;
#endif
};
static inline struct device *kobj_to_dev(struct kobject *kobj)
{
return container_of(kobj, struct device, kobj);
}
/**
* device_iommu_mapped - Returns true when the device DMA is translated
* by an IOMMU
* @dev: Device to perform the check on
*/
static inline bool device_iommu_mapped(struct device *dev)
{
return (dev->iommu_group != NULL);
}
/* Get the wakeup routines, which depend on struct device */
#include <linux/pm_wakeup.h>
static inline const char *dev_name(const struct device *dev)
{
/* Use the init name until the kobject becomes available */
if (dev->init_name)
return dev->init_name;
return kobject_name(&dev->kobj);
}
extern __printf(2, 3)
int dev_set_name(struct device *dev, const char *name, ...);
#ifdef CONFIG_NUMA
static inline int dev_to_node(struct device *dev)
{
return dev->numa_node;
}
static inline void set_dev_node(struct device *dev, int node)
{
dev->numa_node = node;
}
#else
static inline int dev_to_node(struct device *dev)
{
mm: replace all open encodings for NUMA_NO_NODE Patch series "Replace all open encodings for NUMA_NO_NODE", v3. All these places for replacement were found by running the following grep patterns on the entire kernel code. Please let me know if this might have missed some instances. This might also have replaced some false positives. I will appreciate suggestions, inputs and review. 1. git grep "nid == -1" 2. git grep "node == -1" 3. git grep "nid = -1" 4. git grep "node = -1" This patch (of 2): At present there are multiple places where invalid node number is encoded as -1. Even though implicitly understood it is always better to have macros in there. Replace these open encodings for an invalid node number with the global macro NUMA_NO_NODE. This helps remove NUMA related assumptions like 'invalid node' from various places redirecting them to a common definition. Link: http://lkml.kernel.org/r/1545127933-10711-2-git-send-email-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> [ixgbe] Acked-by: Jens Axboe <axboe@kernel.dk> [mtip32xx] Acked-by: Vinod Koul <vkoul@kernel.org> [dmaengine.c] Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Acked-by: Doug Ledford <dledford@redhat.com> [drivers/infiniband] Cc: Joseph Qi <jiangqi903@gmail.com> Cc: Hans Verkuil <hverkuil@xs4all.nl> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-06 06:42:58 +07:00
return NUMA_NO_NODE;
}
static inline void set_dev_node(struct device *dev, int node)
{
}
#endif
static inline struct irq_domain *dev_get_msi_domain(const struct device *dev)
{
#ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
return dev->msi_domain;
#else
return NULL;
#endif
}
static inline void dev_set_msi_domain(struct device *dev, struct irq_domain *d)
{
#ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
dev->msi_domain = d;
#endif
}
static inline void *dev_get_drvdata(const struct device *dev)
{
return dev->driver_data;
}
static inline void dev_set_drvdata(struct device *dev, void *data)
{
dev->driver_data = data;
}
static inline struct pm_subsys_data *dev_to_psd(struct device *dev)
{
return dev ? dev->power.subsys_data : NULL;
}
static inline unsigned int dev_get_uevent_suppress(const struct device *dev)
{
return dev->kobj.uevent_suppress;
}
static inline void dev_set_uevent_suppress(struct device *dev, int val)
{
dev->kobj.uevent_suppress = val;
}
static inline int device_is_registered(struct device *dev)
{
return dev->kobj.state_in_sysfs;
}
PM: Asynchronous suspend and resume of devices Theoretically, the total time of system sleep transitions (suspend to RAM, hibernation) can be reduced by running suspend and resume callbacks of device drivers in parallel with each other. However, there are dependencies between devices such that we're not allowed to suspend the parent of a device before suspending the device itself. Analogously, we're not allowed to resume a device before resuming its parent. The most straightforward way to take these dependencies into accout is to start the async threads used for suspending and resuming devices at the core level, so that async_schedule() is called for each suspend and resume callback supposed to be executed asynchronously. For this purpose, introduce a new device flag, power.async_suspend, used to mark the devices whose suspend and resume callbacks are to be executed asynchronously (ie. in parallel with the main suspend/resume thread and possibly in parallel with each other) and helper function device_enable_async_suspend() allowing one to set power.async_suspend for given device (power.async_suspend is unset by default for all devices). For each device with the power.async_suspend flag set the PM core will use async_schedule() to execute its suspend and resume callbacks. The async threads started for different devices as a result of calling async_schedule() are synchronized with each other and with the main suspend/resume thread with the help of completions, in the following way: (1) There is a completion, power.completion, for each device object. (2) Each device's completion is reset before calling async_schedule() for the device or, in the case of devices with the power.async_suspend flags unset, before executing the device's suspend and resume callbacks. (3) During suspend, right before running the bus type, device type and device class suspend callbacks for the device, the PM core waits for the completions of all the device's children to be completed. (4) During resume, right before running the bus type, device type and device class resume callbacks for the device, the PM core waits for the completion of the device's parent to be completed. (5) The PM core completes power.completion for each device right after the bus type, device type and device class suspend (or resume) callbacks executed for the device have returned. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-01-24 04:23:32 +07:00
static inline void device_enable_async_suspend(struct device *dev)
{
if (!dev->power.is_prepared)
PM: Asynchronous suspend and resume of devices Theoretically, the total time of system sleep transitions (suspend to RAM, hibernation) can be reduced by running suspend and resume callbacks of device drivers in parallel with each other. However, there are dependencies between devices such that we're not allowed to suspend the parent of a device before suspending the device itself. Analogously, we're not allowed to resume a device before resuming its parent. The most straightforward way to take these dependencies into accout is to start the async threads used for suspending and resuming devices at the core level, so that async_schedule() is called for each suspend and resume callback supposed to be executed asynchronously. For this purpose, introduce a new device flag, power.async_suspend, used to mark the devices whose suspend and resume callbacks are to be executed asynchronously (ie. in parallel with the main suspend/resume thread and possibly in parallel with each other) and helper function device_enable_async_suspend() allowing one to set power.async_suspend for given device (power.async_suspend is unset by default for all devices). For each device with the power.async_suspend flag set the PM core will use async_schedule() to execute its suspend and resume callbacks. The async threads started for different devices as a result of calling async_schedule() are synchronized with each other and with the main suspend/resume thread with the help of completions, in the following way: (1) There is a completion, power.completion, for each device object. (2) Each device's completion is reset before calling async_schedule() for the device or, in the case of devices with the power.async_suspend flags unset, before executing the device's suspend and resume callbacks. (3) During suspend, right before running the bus type, device type and device class suspend callbacks for the device, the PM core waits for the completions of all the device's children to be completed. (4) During resume, right before running the bus type, device type and device class resume callbacks for the device, the PM core waits for the completion of the device's parent to be completed. (5) The PM core completes power.completion for each device right after the bus type, device type and device class suspend (or resume) callbacks executed for the device have returned. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-01-24 04:23:32 +07:00
dev->power.async_suspend = true;
}
static inline void device_disable_async_suspend(struct device *dev)
{
if (!dev->power.is_prepared)
dev->power.async_suspend = false;
}
static inline bool device_async_suspend_enabled(struct device *dev)
{
return !!dev->power.async_suspend;
}
PM / core: Add support to skip power management in device/driver model All device objects in the driver model contain fields that control the handling of various power management activities. However, it's not always useful. There are few instances where pseudo devices are added to the model just to take advantage of many other features like kobjects, udev events, and so on. One such example is cpu devices and their caches. The sysfs for the cpu caches are managed by adding devices with cpu as the parent in cpu_device_create() when secondary cpu is brought online. Generally when the secondary CPUs are hotplugged back in as part of resume from suspend-to-ram, we call cpu_device_create() from the cpu hotplug state machine while the cpu device associated with that CPU is not yet ready to be resumed as the device_resume() call happens bit later. It's not really needed to set the flag is_prepared for cpu devices as they are mostly pseudo device and hotplug framework deals with state machine and not managed through the cpu device. This often results in annoying warning when resuming: Enabling non-boot CPUs ... CPU1: Booted secondary processor cache: parent cpu1 should not be sleeping CPU1 is up CPU2: Booted secondary processor cache: parent cpu2 should not be sleeping CPU2 is up .... and so on. So in order to fix these kind of errors, we could just completely avoid doing any power management related initialisations and operations if they are not used by these devices. Add no_pm flags to indicate that the device doesn't require any sort of PM activities and all of them can be completely skipped. We can use the same flag to also avoid adding not used *power* sysfs entries for these devices. For now, lets use this for cpu cache devices. Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Tested-by: Eugeniu Rosca <erosca@de.adit-jv.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-02-15 01:29:10 +07:00
static inline bool device_pm_not_required(struct device *dev)
{
return dev->power.no_pm;
}
static inline void device_set_pm_not_required(struct device *dev)
{
dev->power.no_pm = true;
}
static inline void dev_pm_syscore_device(struct device *dev, bool val)
{
#ifdef CONFIG_PM_SLEEP
dev->power.syscore = val;
#endif
}
PM / core: Add NEVER_SKIP and SMART_PREPARE driver flags The motivation for this change is to provide a way to work around a problem with the direct-complete mechanism used for avoiding system suspend/resume handling for devices in runtime suspend. The problem is that some middle layer code (the PCI bus type and the ACPI PM domain in particular) returns positive values from its system suspend ->prepare callbacks regardless of whether the driver's ->prepare returns a positive value or 0, which effectively prevents drivers from being able to control the direct-complete feature. Some drivers need that control, however, and the PCI bus type has grown its own flag to deal with this issue, but since it is not limited to PCI, it is better to address it by adding driver flags at the core level. To that end, add a driver_flags field to struct dev_pm_info for flags that can be set by device drivers at the probe time to inform the PM core and/or bus types, PM domains and so on on the capabilities and/or preferences of device drivers. Also add two static inline helpers for setting that field and testing it against a given set of flags and make the driver core clear it automatically on driver remove and probe failures. Define and document two PM driver flags related to the direct- complete feature: NEVER_SKIP and SMART_PREPARE that can be used, respectively, to indicate to the PM core that the direct-complete mechanism should never be used for the device and to inform the middle layer code (bus types, PM domains etc) that it can only request the PM core to use the direct-complete mechanism for the device (by returning a positive value from its ->prepare callback) if it also has been requested by the driver. While at it, make the core check pm_runtime_suspended() when setting power.direct_complete so that it doesn't need to be checked by ->prepare callbacks. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
2017-10-25 19:12:29 +07:00
static inline void dev_pm_set_driver_flags(struct device *dev, u32 flags)
{
dev->power.driver_flags = flags;
}
static inline bool dev_pm_test_driver_flags(struct device *dev, u32 flags)
{
return !!(dev->power.driver_flags & flags);
}
Driver core: create lock/unlock functions for struct device In the future, we are going to be changing the lock type for struct device (once we get the lockdep infrastructure properly worked out) To make that changeover easier, and to possibly burry the lock in a different part of struct device, let's create some functions to lock and unlock a device so that no out-of-core code needs to be changed in the future. This patch creates the device_lock/unlock/trylock() functions, and converts all in-tree users to them. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jean Delvare <khali@linux-fr.org> Cc: Dave Young <hidave.darkstar@gmail.com> Cc: Ming Lei <tom.leiming@gmail.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Phil Carmody <ext-phil.2.carmody@nokia.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Cc: Len Brown <len.brown@intel.com> Cc: Magnus Damm <damm@igel.co.jp> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Stefan Richter <stefanr@s5r6.in-berlin.de> Cc: David Brownell <dbrownell@users.sourceforge.net> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Cc: Alex Chiang <achiang@hp.com> Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrew Patterson <andrew.patterson@hp.com> Cc: Yu Zhao <yu.zhao@intel.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Samuel Ortiz <sameo@linux.intel.com> Cc: Wolfram Sang <w.sang@pengutronix.de> Cc: CHENG Renquan <rqcheng@smu.edu.sg> Cc: Oliver Neukum <oliver@neukum.org> Cc: Frans Pop <elendil@planet.nl> Cc: David Vrabel <david.vrabel@csr.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-02-18 01:57:05 +07:00
static inline void device_lock(struct device *dev)
{
mutex_lock(&dev->mutex);
Driver core: create lock/unlock functions for struct device In the future, we are going to be changing the lock type for struct device (once we get the lockdep infrastructure properly worked out) To make that changeover easier, and to possibly burry the lock in a different part of struct device, let's create some functions to lock and unlock a device so that no out-of-core code needs to be changed in the future. This patch creates the device_lock/unlock/trylock() functions, and converts all in-tree users to them. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jean Delvare <khali@linux-fr.org> Cc: Dave Young <hidave.darkstar@gmail.com> Cc: Ming Lei <tom.leiming@gmail.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Phil Carmody <ext-phil.2.carmody@nokia.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Cc: Len Brown <len.brown@intel.com> Cc: Magnus Damm <damm@igel.co.jp> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Stefan Richter <stefanr@s5r6.in-berlin.de> Cc: David Brownell <dbrownell@users.sourceforge.net> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Cc: Alex Chiang <achiang@hp.com> Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrew Patterson <andrew.patterson@hp.com> Cc: Yu Zhao <yu.zhao@intel.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Samuel Ortiz <sameo@linux.intel.com> Cc: Wolfram Sang <w.sang@pengutronix.de> Cc: CHENG Renquan <rqcheng@smu.edu.sg> Cc: Oliver Neukum <oliver@neukum.org> Cc: Frans Pop <elendil@planet.nl> Cc: David Vrabel <david.vrabel@csr.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-02-18 01:57:05 +07:00
}
static inline int device_lock_interruptible(struct device *dev)
{
return mutex_lock_interruptible(&dev->mutex);
}
Driver core: create lock/unlock functions for struct device In the future, we are going to be changing the lock type for struct device (once we get the lockdep infrastructure properly worked out) To make that changeover easier, and to possibly burry the lock in a different part of struct device, let's create some functions to lock and unlock a device so that no out-of-core code needs to be changed in the future. This patch creates the device_lock/unlock/trylock() functions, and converts all in-tree users to them. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jean Delvare <khali@linux-fr.org> Cc: Dave Young <hidave.darkstar@gmail.com> Cc: Ming Lei <tom.leiming@gmail.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Phil Carmody <ext-phil.2.carmody@nokia.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Cc: Len Brown <len.brown@intel.com> Cc: Magnus Damm <damm@igel.co.jp> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Stefan Richter <stefanr@s5r6.in-berlin.de> Cc: David Brownell <dbrownell@users.sourceforge.net> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Cc: Alex Chiang <achiang@hp.com> Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrew Patterson <andrew.patterson@hp.com> Cc: Yu Zhao <yu.zhao@intel.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Samuel Ortiz <sameo@linux.intel.com> Cc: Wolfram Sang <w.sang@pengutronix.de> Cc: CHENG Renquan <rqcheng@smu.edu.sg> Cc: Oliver Neukum <oliver@neukum.org> Cc: Frans Pop <elendil@planet.nl> Cc: David Vrabel <david.vrabel@csr.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-02-18 01:57:05 +07:00
static inline int device_trylock(struct device *dev)
{
return mutex_trylock(&dev->mutex);
Driver core: create lock/unlock functions for struct device In the future, we are going to be changing the lock type for struct device (once we get the lockdep infrastructure properly worked out) To make that changeover easier, and to possibly burry the lock in a different part of struct device, let's create some functions to lock and unlock a device so that no out-of-core code needs to be changed in the future. This patch creates the device_lock/unlock/trylock() functions, and converts all in-tree users to them. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jean Delvare <khali@linux-fr.org> Cc: Dave Young <hidave.darkstar@gmail.com> Cc: Ming Lei <tom.leiming@gmail.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Phil Carmody <ext-phil.2.carmody@nokia.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Cc: Len Brown <len.brown@intel.com> Cc: Magnus Damm <damm@igel.co.jp> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Stefan Richter <stefanr@s5r6.in-berlin.de> Cc: David Brownell <dbrownell@users.sourceforge.net> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Cc: Alex Chiang <achiang@hp.com> Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrew Patterson <andrew.patterson@hp.com> Cc: Yu Zhao <yu.zhao@intel.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Samuel Ortiz <sameo@linux.intel.com> Cc: Wolfram Sang <w.sang@pengutronix.de> Cc: CHENG Renquan <rqcheng@smu.edu.sg> Cc: Oliver Neukum <oliver@neukum.org> Cc: Frans Pop <elendil@planet.nl> Cc: David Vrabel <david.vrabel@csr.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-02-18 01:57:05 +07:00
}
static inline void device_unlock(struct device *dev)
{
mutex_unlock(&dev->mutex);
Driver core: create lock/unlock functions for struct device In the future, we are going to be changing the lock type for struct device (once we get the lockdep infrastructure properly worked out) To make that changeover easier, and to possibly burry the lock in a different part of struct device, let's create some functions to lock and unlock a device so that no out-of-core code needs to be changed in the future. This patch creates the device_lock/unlock/trylock() functions, and converts all in-tree users to them. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jean Delvare <khali@linux-fr.org> Cc: Dave Young <hidave.darkstar@gmail.com> Cc: Ming Lei <tom.leiming@gmail.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Phil Carmody <ext-phil.2.carmody@nokia.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Cc: Len Brown <len.brown@intel.com> Cc: Magnus Damm <damm@igel.co.jp> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Stefan Richter <stefanr@s5r6.in-berlin.de> Cc: David Brownell <dbrownell@users.sourceforge.net> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Cc: Alex Chiang <achiang@hp.com> Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrew Patterson <andrew.patterson@hp.com> Cc: Yu Zhao <yu.zhao@intel.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Samuel Ortiz <sameo@linux.intel.com> Cc: Wolfram Sang <w.sang@pengutronix.de> Cc: CHENG Renquan <rqcheng@smu.edu.sg> Cc: Oliver Neukum <oliver@neukum.org> Cc: Frans Pop <elendil@planet.nl> Cc: David Vrabel <david.vrabel@csr.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-02-18 01:57:05 +07:00
}
static inline void device_lock_assert(struct device *dev)
{
lockdep_assert_held(&dev->mutex);
}
static inline struct device_node *dev_of_node(struct device *dev)
{
if (!IS_ENABLED(CONFIG_OF) || !dev)
return NULL;
return dev->of_node;
}
static inline bool dev_has_sync_state(struct device *dev)
{
if (!dev)
return false;
if (dev->driver && dev->driver->sync_state)
return true;
if (dev->bus && dev->bus->sync_state)
return true;
return false;
}
/*
* High level routines for use by the bus drivers
*/
extern int __must_check device_register(struct device *dev);
extern void device_unregister(struct device *dev);
extern void device_initialize(struct device *dev);
extern int __must_check device_add(struct device *dev);
extern void device_del(struct device *dev);
extern int device_for_each_child(struct device *dev, void *data,
int (*fn)(struct device *dev, void *data));
extern int device_for_each_child_reverse(struct device *dev, void *data,
int (*fn)(struct device *dev, void *data));
extern struct device *device_find_child(struct device *dev, void *data,
int (*match)(struct device *dev, void *data));
extern struct device *device_find_child_by_name(struct device *parent,
const char *name);
extern int device_rename(struct device *dev, const char *new_name);
extern int device_move(struct device *dev, struct device *new_parent,
enum dpm_order dpm_order);
extern int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid);
extern const char *device_get_devnode(struct device *dev,
umode_t *mode, kuid_t *uid, kgid_t *gid,
const char **tmp);
Driver core: Add offline/online device operations In some cases, graceful hot-removal of devices is not possible, although in principle the devices in question support hotplug. For example, that may happen for the last CPU in the system or for memory modules holding kernel memory. In those cases it is nice to be able to check if the given device can be gracefully hot-removed before triggering a removal procedure that cannot be aborted or reversed. Unfortunately, however, the kernel currently doesn't provide any support for that. To address that deficiency, introduce support for offline and online operations that can be performed on devices, respectively, before a hot-removal and in case when it is necessary (or convenient) to put a device back online after a successful offline (that has not been followed by removal). The idea is that the offline will fail whenever the given device cannot be gracefully removed from the system and it will not be allowed to use the device after a successful offline (until a subsequent online) in analogy with the existing CPU offline/online mechanism. For now, the offline and online operations are introduced at the bus type level, as that should be sufficient for the most urgent use cases (CPUs and memory modules). In the future, however, the approach may be extended to cover some more complicated device offline/online scenarios involving device drivers etc. The lock_device_hotplug() and unlock_device_hotplug() functions are introduced because subsequent patches need to put larger pieces of code under device_hotplug_lock to prevent race conditions between device offline and removal from happening. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Toshi Kani <toshi.kani@hp.com>
2013-05-03 03:15:29 +07:00
static inline bool device_supports_offline(struct device *dev)
{
return dev->bus && dev->bus->offline && dev->bus->online;
}
extern void lock_device_hotplug(void);
extern void unlock_device_hotplug(void);
driver core / ACPI: Avoid device hot remove locking issues device_hotplug_lock is held around the acpi_bus_trim() call in acpi_scan_hot_remove() which generally removes devices (it removes ACPI device objects at least, but it may also remove "physical" device objects through .detach() callbacks of ACPI scan handlers). Thus, potentially, device sysfs attributes are removed under that lock and to remove those attributes it is necessary to hold the s_active references of their directory entries for writing. On the other hand, the execution of a .show() or .store() callback from a sysfs attribute is carried out with that attribute's s_active reference held for reading. Consequently, if any device sysfs attribute that may be removed from within acpi_scan_hot_remove() through acpi_bus_trim() has a .store() or .show() callback which acquires device_hotplug_lock, the execution of that callback may deadlock with the removal of the attribute. [Unfortunately, the "online" device attribute of CPUs and memory blocks is one of them.] To avoid such deadlocks, make all of the sysfs attribute callbacks that need to lock device hotplug, for example store_online(), use a special function, lock_device_hotplug_sysfs(), to lock device hotplug and return the result of that function immediately if it is not zero. This will cause the s_active reference of the directory entry in question to be released and the syscall to be restarted if device_hotplug_lock cannot be acquired. [show_online() actually doesn't need to lock device hotplug, but it is useful to serialize it with respect to device_offline() and device_online() for the same device (in case user space attempts to run them concurrently) which can be done with the help of device_lock().] Reported-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Reported-and-tested-by: Gu Zheng <guz.fnst@cn.fujitsu.com> Suggested-by: Tejun Heo <tj@kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Toshi Kani <toshi.kani@hp.com>
2013-08-29 02:41:01 +07:00
extern int lock_device_hotplug_sysfs(void);
Driver core: Add offline/online device operations In some cases, graceful hot-removal of devices is not possible, although in principle the devices in question support hotplug. For example, that may happen for the last CPU in the system or for memory modules holding kernel memory. In those cases it is nice to be able to check if the given device can be gracefully hot-removed before triggering a removal procedure that cannot be aborted or reversed. Unfortunately, however, the kernel currently doesn't provide any support for that. To address that deficiency, introduce support for offline and online operations that can be performed on devices, respectively, before a hot-removal and in case when it is necessary (or convenient) to put a device back online after a successful offline (that has not been followed by removal). The idea is that the offline will fail whenever the given device cannot be gracefully removed from the system and it will not be allowed to use the device after a successful offline (until a subsequent online) in analogy with the existing CPU offline/online mechanism. For now, the offline and online operations are introduced at the bus type level, as that should be sufficient for the most urgent use cases (CPUs and memory modules). In the future, however, the approach may be extended to cover some more complicated device offline/online scenarios involving device drivers etc. The lock_device_hotplug() and unlock_device_hotplug() functions are introduced because subsequent patches need to put larger pieces of code under device_hotplug_lock to prevent race conditions between device offline and removal from happening. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Toshi Kani <toshi.kani@hp.com>
2013-05-03 03:15:29 +07:00
extern int device_offline(struct device *dev);
extern int device_online(struct device *dev);
2015-04-04 04:23:37 +07:00
extern void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode);
extern void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode);
driver core: add helper to reuse a device-tree node Add a helper function to be used when reusing the device-tree node of another device. It is fairly common for drivers to reuse the device-tree node of a parent (or other ancestor) device when creating class or bus devices (e.g. gpio chips, i2c adapters, iio chips, spi masters, serdev, phys, usb root hubs). But reusing a device-tree node may cause problems if the new device is later probed as for example driver core would currently attempt to reinitialise an already active associated pinmux configuration. Other potential issues include the platform-bus code unconditionally dropping the device-tree node reference in its device destructor, reinitialisation of other bus-managed resources such as clocks, and the recently added DMA-setup in driver core. Note that for most examples above this is currently not an issue as the devices are never probed, but this is a problem for the USB bus which has recently gained device-tree support. This was discovered and worked-around in a rather ad-hoc fashion by commit dc5878abf49c ("usb: core: move root hub's device node assignment after it is added to bus") by not setting the of_node pointer until after the root-hub device has been registered. Instead we can allow devices to reuse a device-tree node by setting a flag in their struct device that can be used by core, bus and driver code to avoid resources from being over-allocated. Note that the helper also grabs an extra reference to the device node, which specifically balances the unconditional put in the platform-device destructor. Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-06 22:59:00 +07:00
void device_set_of_node_from_dev(struct device *dev, const struct device *dev2);
2015-04-04 04:23:37 +07:00
static inline int dev_num_vf(struct device *dev)
{
if (dev->bus && dev->bus->num_vf)
return dev->bus->num_vf(dev);
return 0;
}
/*
* Root device objects for grouping under /sys/devices
*/
extern struct device *__root_device_register(const char *name,
struct module *owner);
/* This is a macro to avoid include problems with THIS_MODULE */
#define root_device_register(name) \
__root_device_register(name, THIS_MODULE)
extern void root_device_unregister(struct device *root);
static inline void *dev_get_platdata(const struct device *dev)
{
return dev->platform_data;
}
/*
* Manual binding of a device to driver. See drivers/base/bus.c
* for information on use.
*/
extern int __must_check device_bind_driver(struct device *dev);
extern void device_release_driver(struct device *dev);
extern int __must_check device_attach(struct device *dev);
extern int __must_check driver_attach(struct device_driver *drv);
extern void device_initial_probe(struct device *dev);
extern int __must_check device_reprobe(struct device *dev);
extern bool device_is_bound(struct device *dev);
/*
* Easy functions for dynamically creating devices on the fly
*/
extern __printf(5, 0)
struct device *device_create_vargs(struct class *cls, struct device *parent,
dev_t devt, void *drvdata,
const char *fmt, va_list vargs);
extern __printf(5, 6)
struct device *device_create(struct class *cls, struct device *parent,
dev_t devt, void *drvdata,
const char *fmt, ...);
extern __printf(6, 7)
struct device *device_create_with_groups(struct class *cls,
struct device *parent, dev_t devt, void *drvdata,
const struct attribute_group **groups,
const char *fmt, ...);
extern void device_destroy(struct class *cls, dev_t devt);
extern int __must_check device_add_groups(struct device *dev,
const struct attribute_group **groups);
extern void device_remove_groups(struct device *dev,
const struct attribute_group **groups);
static inline int __must_check device_add_group(struct device *dev,
const struct attribute_group *grp)
{
const struct attribute_group *groups[] = { grp, NULL };
return device_add_groups(dev, groups);
}
static inline void device_remove_group(struct device *dev,
const struct attribute_group *grp)
{
const struct attribute_group *groups[] = { grp, NULL };
return device_remove_groups(dev, groups);
}
extern int __must_check devm_device_add_groups(struct device *dev,
const struct attribute_group **groups);
extern void devm_device_remove_groups(struct device *dev,
const struct attribute_group **groups);
extern int __must_check devm_device_add_group(struct device *dev,
const struct attribute_group *grp);
extern void devm_device_remove_group(struct device *dev,
const struct attribute_group *grp);
/*
* Platform "fixup" functions - allow the platform to have their say
* about devices and actions that the general device layer doesn't
* know about.
*/
/* Notify platform of device discovery */
extern int (*platform_notify)(struct device *dev);
extern int (*platform_notify_remove)(struct device *dev);
/*
* get_device - atomically increment the reference count for the device.
*
*/
extern struct device *get_device(struct device *dev);
extern void put_device(struct device *dev);
drivers/base: Introduce kill_device() The libnvdimm subsystem arranges for devices to be destroyed as a result of a sysfs operation. Since device_unregister() cannot be called from an actively running sysfs attribute of the same device libnvdimm arranges for device_unregister() to be performed in an out-of-line async context. The driver core maintains a 'dead' state for coordinating its own racing async registration / de-registration requests. Rather than add local 'dead' state tracking infrastructure to libnvdimm device objects, export the existing state tracking via a new kill_device() helper. The kill_device() helper simply marks the device as dead, i.e. that it is on its way to device_del(), or returns that the device was already dead. This can be used in advance of calling device_unregister() for subsystems like libnvdimm that might need to handle multiple user threads racing to delete a device. This refactoring does not change any behavior, but it is a pre-requisite for follow-on fixes and therefore marked for -stable. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Fixes: 4d88a97aa9e8 ("libnvdimm, nvdimm: dimm driver and base libnvdimm device-driver...") Cc: <stable@vger.kernel.org> Tested-by: Jane Chu <jane.chu@oracle.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/156341207332.292348.14959761496009347574.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2019-07-18 08:07:53 +07:00
extern bool kill_device(struct device *dev);
Driver Core: devtmpfs - kernel-maintained tmpfs-based /dev Devtmpfs lets the kernel create a tmpfs instance called devtmpfs very early at kernel initialization, before any driver-core device is registered. Every device with a major/minor will provide a device node in devtmpfs. Devtmpfs can be changed and altered by userspace at any time, and in any way needed - just like today's udev-mounted tmpfs. Unmodified udev versions will run just fine on top of it, and will recognize an already existing kernel-created device node and use it. The default node permissions are root:root 0600. Proper permissions and user/group ownership, meaningful symlinks, all other policy still needs to be applied by userspace. If a node is created by devtmps, devtmpfs will remove the device node when the device goes away. If the device node was created by userspace, or the devtmpfs created node was replaced by userspace, it will no longer be removed by devtmpfs. If it is requested to auto-mount it, it makes init=/bin/sh work without any further userspace support. /dev will be fully populated and dynamic, and always reflect the current device state of the kernel. With the commonly used dynamic device numbers, it solves the problem where static devices nodes may point to the wrong devices. It is intended to make the initial bootup logic simpler and more robust, by de-coupling the creation of the inital environment, to reliably run userspace processes, from a complex userspace bootstrap logic to provide a working /dev. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Jan Blunck <jblunck@suse.de> Tested-By: Harald Hoyer <harald@redhat.com> Tested-By: Scott James Remnant <scott@ubuntu.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-04-30 20:23:42 +07:00
#ifdef CONFIG_DEVTMPFS
extern int devtmpfs_mount(void);
Driver Core: devtmpfs - kernel-maintained tmpfs-based /dev Devtmpfs lets the kernel create a tmpfs instance called devtmpfs very early at kernel initialization, before any driver-core device is registered. Every device with a major/minor will provide a device node in devtmpfs. Devtmpfs can be changed and altered by userspace at any time, and in any way needed - just like today's udev-mounted tmpfs. Unmodified udev versions will run just fine on top of it, and will recognize an already existing kernel-created device node and use it. The default node permissions are root:root 0600. Proper permissions and user/group ownership, meaningful symlinks, all other policy still needs to be applied by userspace. If a node is created by devtmps, devtmpfs will remove the device node when the device goes away. If the device node was created by userspace, or the devtmpfs created node was replaced by userspace, it will no longer be removed by devtmpfs. If it is requested to auto-mount it, it makes init=/bin/sh work without any further userspace support. /dev will be fully populated and dynamic, and always reflect the current device state of the kernel. With the commonly used dynamic device numbers, it solves the problem where static devices nodes may point to the wrong devices. It is intended to make the initial bootup logic simpler and more robust, by de-coupling the creation of the inital environment, to reliably run userspace processes, from a complex userspace bootstrap logic to provide a working /dev. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Jan Blunck <jblunck@suse.de> Tested-By: Harald Hoyer <harald@redhat.com> Tested-By: Scott James Remnant <scott@ubuntu.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-04-30 20:23:42 +07:00
#else
static inline int devtmpfs_mount(void) { return 0; }
Driver Core: devtmpfs - kernel-maintained tmpfs-based /dev Devtmpfs lets the kernel create a tmpfs instance called devtmpfs very early at kernel initialization, before any driver-core device is registered. Every device with a major/minor will provide a device node in devtmpfs. Devtmpfs can be changed and altered by userspace at any time, and in any way needed - just like today's udev-mounted tmpfs. Unmodified udev versions will run just fine on top of it, and will recognize an already existing kernel-created device node and use it. The default node permissions are root:root 0600. Proper permissions and user/group ownership, meaningful symlinks, all other policy still needs to be applied by userspace. If a node is created by devtmps, devtmpfs will remove the device node when the device goes away. If the device node was created by userspace, or the devtmpfs created node was replaced by userspace, it will no longer be removed by devtmpfs. If it is requested to auto-mount it, it makes init=/bin/sh work without any further userspace support. /dev will be fully populated and dynamic, and always reflect the current device state of the kernel. With the commonly used dynamic device numbers, it solves the problem where static devices nodes may point to the wrong devices. It is intended to make the initial bootup logic simpler and more robust, by de-coupling the creation of the inital environment, to reliably run userspace processes, from a complex userspace bootstrap logic to provide a working /dev. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Jan Blunck <jblunck@suse.de> Tested-By: Harald Hoyer <harald@redhat.com> Tested-By: Scott James Remnant <scott@ubuntu.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-04-30 20:23:42 +07:00
#endif
/* drivers/base/power/shutdown.c */
extern void device_shutdown(void);
/* debugging and troubleshooting/diagnostic helpers. */
extern const char *dev_driver_string(const struct device *dev);
driver core: Functional dependencies tracking support Currently, there is a problem with taking functional dependencies between devices into account. What I mean by a "functional dependency" is when the driver of device B needs device A to be functional and (generally) its driver to be present in order to work properly. This has certain consequences for power management (suspend/resume and runtime PM ordering) and shutdown ordering of these devices. In general, it also implies that the driver of A needs to be working for B to be probed successfully and it cannot be unbound from the device before the B's driver. Support for representing those functional dependencies between devices is added here to allow the driver core to track them and act on them in certain cases where applicable. The argument for doing that in the driver core is that there are quite a few distinct use cases involving device dependencies, they are relatively hard to get right in a driver (if one wants to address all of them properly) and it only gets worse if multiplied by the number of drivers potentially needing to do it. Morever, at least one case (asynchronous system suspend/resume) cannot be handled in a single driver at all, because it requires the driver of A to wait for B to suspend (during system suspend) and the driver of B to wait for A to resume (during system resume). For this reason, represent dependencies between devices as "links", with the help of struct device_link objects each containing pointers to the "linked" devices, a list node for each of them, status information, flags, and an RCU head for synchronization. Also add two new list heads, representing the lists of links to the devices that depend on the given one (consumers) and to the devices depended on by it (suppliers), and a "driver presence status" field (needed for figuring out initial states of device links) to struct device. The entire data structure consisting of all of the lists of link objects for all devices is protected by a mutex (for link object addition/removal and for list walks during device driver probing and removal) and by SRCU (for list walking in other case that will be introduced by subsequent change sets). If CONFIG_SRCU is not selected, however, an rwsem is used for protecting the entire data structure. In addition, each link object has an internal status field whose value reflects whether or not drivers are bound to the devices pointed to by the link or probing/removal of their drivers is in progress etc. That field is only modified under the device links mutex, but it may be read outside of it in some cases (introduced by subsequent change sets), so modifications of it are annotated with WRITE_ONCE(). New links are added by calling device_link_add() which takes three arguments: pointers to the devices in question and flags. In particular, if DL_FLAG_STATELESS is set in the flags, the link status is not to be taken into account for this link and the driver core will not manage it. In turn, if DL_FLAG_AUTOREMOVE is set in the flags, the driver core will remove the link automatically when the consumer device driver unbinds from it. One of the actions carried out by device_link_add() is to reorder the lists used for device shutdown and system suspend/resume to put the consumer device along with all of its children and all of its consumers (and so on, recursively) to the ends of those lists in order to ensure the right ordering between all of the supplier and consumer devices. For this reason, it is not possible to create a link between two devices if the would-be supplier device already depends on the would-be consumer device as either a direct descendant of it or a consumer of one of its direct descendants or one of its consumers and so on. There are two types of link objects, persistent and non-persistent. The persistent ones stay around until one of the target devices is deleted, while the non-persistent ones are removed automatically when the consumer driver unbinds from its device (ie. they are assumed to be valid only as long as the consumer device has a driver bound to it). Persistent links are created by default and non-persistent links are created when the DL_FLAG_AUTOREMOVE flag is passed to device_link_add(). Both persistent and non-persistent device links can be deleted with an explicit call to device_link_del(). Links created without the DL_FLAG_STATELESS flag set are managed by the driver core using a simple state machine. There are 5 states each link can be in: DORMANT (unused), AVAILABLE (the supplier driver is present and functional), CONSUMER_PROBE (the consumer driver is probing), ACTIVE (both supplier and consumer drivers are present and functional), and SUPPLIER_UNBIND (the supplier driver is unbinding). The driver core updates the link state automatically depending on what happens to the linked devices and for each link state specific actions are taken in addition to that. For example, if the supplier driver unbinds from its device, the driver core will also unbind the drivers of all of its consumers automatically under the assumption that they cannot function properly without the supplier. Analogously, the driver core will only allow the consumer driver to bind to its device if the supplier driver is present and functional (ie. the link is in the AVAILABLE state). If that's not the case, it will rely on the existing deferred probing mechanism to wait for the supplier driver to become available. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-30 23:32:16 +07:00
/* Device links interface. */
struct device_link *device_link_add(struct device *consumer,
struct device *supplier, u32 flags);
void device_link_del(struct device_link *link);
void device_link_remove(void *consumer, struct device *supplier);
driver core: Add sync_state driver/bus callback This sync_state driver/bus callback is called once all the consumers of a supplier have probed successfully. This allows the supplier device's driver/bus to sync the supplier device's state to the software state with the guarantee that all the consumers are actively managing the resources provided by the supplier device. To maintain backwards compatibility and ease transition from existing frameworks and resource cleanup schemes, late_initcall_sync is the earliest when the sync_state callback might be called. There is no upper bound on the time by which the sync_state callback has to be called. This is because if a consumer device never probes, the supplier has to maintain its resources in the state left by the bootloader. For example, if the bootloader leaves the display backlight at a fixed voltage and the backlight driver is never probed, you don't want the backlight to ever be turned off after boot up. Also, when multiple devices are added after kernel init, some suppliers could be added before their consumer devices get added. In these instances, the supplier devices could get their sync_state callback called right after they probe because the consumers devices haven't had a chance to create device links to the suppliers. To handle this correctly, this change also provides APIs to pause/resume sync state callbacks so that when multiple devices are added, their sync_state callback evaluation can be postponed to happen after all of them are added. kbuild test robot reported missing documentation for device.state_synced Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Saravana Kannan <saravanak@google.com> Link: https://lore.kernel.org/r/20190904211126.47518-5-saravanak@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-05 04:11:23 +07:00
void device_links_supplier_sync_state_pause(void);
void device_links_supplier_sync_state_resume(void);
/* Create alias, so I can be autoloaded. */
#define MODULE_ALIAS_CHARDEV(major,minor) \
MODULE_ALIAS("char-major-" __stringify(major) "-" __stringify(minor))
#define MODULE_ALIAS_CHARDEV_MAJOR(major) \
MODULE_ALIAS("char-major-" __stringify(major) "-*")
#ifdef CONFIG_SYSFS_DEPRECATED
extern long sysfs_deprecated;
#else
#define sysfs_deprecated 0
#endif
#endif /* _DEVICE_H_ */