linux_dsm_epyc7002/drivers/pci/hotplug/acpiphp.h
Lukas Wunner a7da21613c PCI: hotplug: Drop hotplug_slot_info
Ever since the PCI hotplug core was introduced in 2002, drivers had to
allocate and register a struct hotplug_slot_info for every slot:
https://git.kernel.org/tglx/history/c/a8a2069f432c

Apparently the idea was that drivers furnish the hotplug core with an
up-to-date card presence status, power status, latch status and
attention indicator status as well as notify the hotplug core of changes
thereof.  However only 4 out of 12 hotplug drivers bother to notify the
hotplug core with pci_hp_change_slot_info() and the hotplug core never
made any use of the information:  There is just a single macro in
pci_hotplug_core.c, GET_STATUS(), which uses the hotplug_slot_info if
the driver lacks the corresponding callback in hotplug_slot_ops.  The
macro is called when the user reads the attribute via sysfs.

Now, if the callback isn't defined, the attribute isn't exposed in sysfs
in the first place (see e.g. has_power_file()).  There are only two
situations when the hotplug_slot_info would actually be accessed:

* If the driver defines ->enable_slot or ->disable_slot but not
  ->get_power_status.

* If the driver defines ->set_attention_status but not
  ->get_attention_status.

There is no driver doing the former and just a single driver doing the
latter, namely pnv_php.c.  Amend it with a ->get_attention_status
callback.  With that, the hotplug_slot_info becomes completely unused by
the PCI hotplug core.  But a few drivers use it internally as a cache:

cpcihp uses it to cache the latch_status and adapter_status.
cpqhp uses it to cache the adapter_status.
pnv_php and rpaphp use it to cache the attention_status.
shpchp uses it to cache all four values.

Amend these drivers to cache the information in their private slot
struct.  shpchp's slot struct already contains members to cache the
power_status and adapter_status, so additional members are only needed
for the other two values.  In the case of cpqphp, the cached value is
only accessed in a single place, so instead of caching it, read the
current value from the hardware.

Caution:  acpiphp, cpci, cpqhp, shpchp, asus-wmi and eeepc-laptop
populate the hotplug_slot_info with initial values on probe.  That code
is herewith removed.  There is a theoretical chance that the code has
side effects without which the driver fails to function, e.g. if the
ACPI method to read the adapter status needs to be executed at least
once on probe.  That seems unlikely to me, still maintainers should
review the changes carefully for this possibility.

Rafael adds: "I'm not aware of any case in which it will break anything,
[...] but if that happens, it may be necessary to add the execution of
the control methods in question directly to the initialization part."

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>  # drivers/pci/hotplug/rpa*
Acked-by: Sebastian Ott <sebott@linux.ibm.com>        # drivers/pci/hotplug/s390*
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # drivers/platform/x86
Cc: Len Brown <lenb@kernel.org>
Cc: Scott Murray <scott@spiteful.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Oliver OHalloran <oliveroh@au1.ibm.com>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Corentin Chary <corentin.chary@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>
2018-09-18 17:52:15 -05:00

188 lines
4.6 KiB
C

/* SPDX-License-Identifier: GPL-2.0+ */
/*
* ACPI PCI Hot Plug Controller Driver
*
* Copyright (C) 1995,2001 Compaq Computer Corporation
* Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
* Copyright (C) 2001 IBM Corp.
* Copyright (C) 2002 Hiroshi Aono (h-aono@ap.jp.nec.com)
* Copyright (C) 2002,2003 Takayoshi Kochi (t-kochi@bq.jp.nec.com)
* Copyright (C) 2002,2003 NEC Corporation
* Copyright (C) 2003-2005 Matthew Wilcox (matthew.wilcox@hp.com)
* Copyright (C) 2003-2005 Hewlett Packard
*
* All rights reserved.
*
* Send feedback to <gregkh@us.ibm.com>,
* <t-kochi@bq.jp.nec.com>
*
*/
#ifndef _ACPIPHP_H
#define _ACPIPHP_H
#include <linux/acpi.h>
#include <linux/mutex.h>
#include <linux/pci_hotplug.h>
struct acpiphp_context;
struct acpiphp_bridge;
struct acpiphp_slot;
/*
* struct slot - slot information for each *physical* slot
*/
struct slot {
struct hotplug_slot *hotplug_slot;
struct acpiphp_slot *acpi_slot;
unsigned int sun; /* ACPI _SUN (Slot User Number) value */
};
static inline const char *slot_name(struct slot *slot)
{
return hotplug_slot_name(slot->hotplug_slot);
}
/*
* struct acpiphp_bridge - PCI bridge information
*
* for each bridge device in ACPI namespace
*/
struct acpiphp_bridge {
struct list_head list;
struct list_head slots;
struct kref ref;
struct acpiphp_context *context;
int nr_slots;
/* This bus (host bridge) or Secondary bus (PCI-to-PCI bridge) */
struct pci_bus *pci_bus;
/* PCI-to-PCI bridge device */
struct pci_dev *pci_dev;
bool is_going_away;
};
/*
* struct acpiphp_slot - PCI slot information
*
* PCI slot information for each *physical* PCI slot
*/
struct acpiphp_slot {
struct list_head node;
struct pci_bus *bus;
struct list_head funcs; /* one slot may have different
objects (i.e. for each function) */
struct slot *slot;
u8 device; /* pci device# */
u32 flags; /* see below */
};
/*
* struct acpiphp_func - PCI function information
*
* PCI function information for each object in ACPI namespace
* typically 8 objects per slot (i.e. for each PCI function)
*/
struct acpiphp_func {
struct acpiphp_bridge *parent;
struct acpiphp_slot *slot;
struct list_head sibling;
u8 function; /* pci function# */
u32 flags; /* see below */
};
struct acpiphp_context {
struct acpi_hotplug_context hp;
struct acpiphp_func func;
struct acpiphp_bridge *bridge;
unsigned int refcount;
};
static inline struct acpiphp_context *to_acpiphp_context(struct acpi_hotplug_context *hp)
{
return container_of(hp, struct acpiphp_context, hp);
}
static inline struct acpiphp_context *func_to_context(struct acpiphp_func *func)
{
return container_of(func, struct acpiphp_context, func);
}
static inline struct acpi_device *func_to_acpi_device(struct acpiphp_func *func)
{
return func_to_context(func)->hp.self;
}
static inline acpi_handle func_to_handle(struct acpiphp_func *func)
{
return func_to_acpi_device(func)->handle;
}
struct acpiphp_root_context {
struct acpi_hotplug_context hp;
struct acpiphp_bridge *root_bridge;
};
static inline struct acpiphp_root_context *to_acpiphp_root_context(struct acpi_hotplug_context *hp)
{
return container_of(hp, struct acpiphp_root_context, hp);
}
/*
* struct acpiphp_attention_info - device specific attention registration
*
* ACPI has no generic method of setting/getting attention status
* this allows for device specific driver registration
*/
struct acpiphp_attention_info
{
int (*set_attn)(struct hotplug_slot *slot, u8 status);
int (*get_attn)(struct hotplug_slot *slot, u8 *status);
struct module *owner;
};
/* ACPI _STA method value (ignore bit 4; battery present) */
#define ACPI_STA_ALL (0x0000000f)
/* slot flags */
#define SLOT_ENABLED (0x00000001)
#define SLOT_IS_GOING_AWAY (0x00000002)
/* function flags */
#define FUNC_HAS_STA (0x00000001)
#define FUNC_HAS_EJ0 (0x00000002)
/* function prototypes */
/* acpiphp_core.c */
int acpiphp_register_attention(struct acpiphp_attention_info *info);
int acpiphp_unregister_attention(struct acpiphp_attention_info *info);
int acpiphp_register_hotplug_slot(struct acpiphp_slot *slot, unsigned int sun);
void acpiphp_unregister_hotplug_slot(struct acpiphp_slot *slot);
/* acpiphp_glue.c */
typedef int (*acpiphp_callback)(struct acpiphp_slot *slot, void *data);
int acpiphp_enable_slot(struct acpiphp_slot *slot);
int acpiphp_disable_slot(struct acpiphp_slot *slot);
u8 acpiphp_get_power_status(struct acpiphp_slot *slot);
u8 acpiphp_get_attention_status(struct acpiphp_slot *slot);
u8 acpiphp_get_latch_status(struct acpiphp_slot *slot);
u8 acpiphp_get_adapter_status(struct acpiphp_slot *slot);
/* variables */
extern bool acpiphp_disabled;
#endif /* _ACPIPHP_H */