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b0b42b16ff
There is a possibility to have two devices registered with the same id. Cc: <stable@kernel.org> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
636 lines
18 KiB
C
636 lines
18 KiB
C
/*
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* Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 59
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* Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* The full GNU General Public License is included in this distribution in the
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* file called COPYING.
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*/
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/*
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* This code implements the DMA subsystem. It provides a HW-neutral interface
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* for other kernel code to use asynchronous memory copy capabilities,
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* if present, and allows different HW DMA drivers to register as providing
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* this capability.
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*
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* Due to the fact we are accelerating what is already a relatively fast
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* operation, the code goes to great lengths to avoid additional overhead,
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* such as locking.
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*
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* LOCKING:
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*
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* The subsystem keeps two global lists, dma_device_list and dma_client_list.
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* Both of these are protected by a mutex, dma_list_mutex.
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*
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* Each device has a channels list, which runs unlocked but is never modified
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* once the device is registered, it's just setup by the driver.
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*
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* Each client is responsible for keeping track of the channels it uses. See
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* the definition of dma_event_callback in dmaengine.h.
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*
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* Each device has a kref, which is initialized to 1 when the device is
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* registered. A kref_get is done for each device registered. When the
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* device is released, the corresponding kref_put is done in the release
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* method. Every time one of the device's channels is allocated to a client,
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* a kref_get occurs. When the channel is freed, the corresponding kref_put
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* happens. The device's release function does a completion, so
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* unregister_device does a remove event, device_unregister, a kref_put
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* for the first reference, then waits on the completion for all other
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* references to finish.
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*
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* Each channel has an open-coded implementation of Rusty Russell's "bigref,"
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* with a kref and a per_cpu local_t. A dma_chan_get is called when a client
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* signals that it wants to use a channel, and dma_chan_put is called when
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* a channel is removed or a client using it is unregistered. A client can
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* take extra references per outstanding transaction, as is the case with
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* the NET DMA client. The release function does a kref_put on the device.
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* -ChrisL, DanW
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/device.h>
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#include <linux/dmaengine.h>
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#include <linux/hardirq.h>
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#include <linux/spinlock.h>
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#include <linux/percpu.h>
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#include <linux/rcupdate.h>
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#include <linux/mutex.h>
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#include <linux/jiffies.h>
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static DEFINE_MUTEX(dma_list_mutex);
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static LIST_HEAD(dma_device_list);
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static LIST_HEAD(dma_client_list);
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/* --- sysfs implementation --- */
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static ssize_t show_memcpy_count(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct dma_chan *chan = to_dma_chan(dev);
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unsigned long count = 0;
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int i;
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for_each_possible_cpu(i)
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count += per_cpu_ptr(chan->local, i)->memcpy_count;
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return sprintf(buf, "%lu\n", count);
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}
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static ssize_t show_bytes_transferred(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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struct dma_chan *chan = to_dma_chan(dev);
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unsigned long count = 0;
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int i;
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for_each_possible_cpu(i)
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count += per_cpu_ptr(chan->local, i)->bytes_transferred;
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return sprintf(buf, "%lu\n", count);
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}
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static ssize_t show_in_use(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct dma_chan *chan = to_dma_chan(dev);
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int in_use = 0;
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if (unlikely(chan->slow_ref) &&
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atomic_read(&chan->refcount.refcount) > 1)
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in_use = 1;
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else {
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if (local_read(&(per_cpu_ptr(chan->local,
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get_cpu())->refcount)) > 0)
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in_use = 1;
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put_cpu();
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}
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return sprintf(buf, "%d\n", in_use);
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}
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static struct device_attribute dma_attrs[] = {
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__ATTR(memcpy_count, S_IRUGO, show_memcpy_count, NULL),
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__ATTR(bytes_transferred, S_IRUGO, show_bytes_transferred, NULL),
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__ATTR(in_use, S_IRUGO, show_in_use, NULL),
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__ATTR_NULL
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};
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static void dma_async_device_cleanup(struct kref *kref);
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static void dma_dev_release(struct device *dev)
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{
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struct dma_chan *chan = to_dma_chan(dev);
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kref_put(&chan->device->refcount, dma_async_device_cleanup);
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}
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static struct class dma_devclass = {
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.name = "dma",
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.dev_attrs = dma_attrs,
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.dev_release = dma_dev_release,
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};
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/* --- client and device registration --- */
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#define dma_chan_satisfies_mask(chan, mask) \
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__dma_chan_satisfies_mask((chan), &(mask))
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static int
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__dma_chan_satisfies_mask(struct dma_chan *chan, dma_cap_mask_t *want)
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{
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dma_cap_mask_t has;
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bitmap_and(has.bits, want->bits, chan->device->cap_mask.bits,
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DMA_TX_TYPE_END);
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return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END);
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}
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/**
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* dma_client_chan_alloc - try to allocate channels to a client
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* @client: &dma_client
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*
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* Called with dma_list_mutex held.
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*/
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static void dma_client_chan_alloc(struct dma_client *client)
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{
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struct dma_device *device;
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struct dma_chan *chan;
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int desc; /* allocated descriptor count */
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enum dma_state_client ack;
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/* Find a channel */
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list_for_each_entry(device, &dma_device_list, global_node) {
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/* Does the client require a specific DMA controller? */
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if (client->slave && client->slave->dma_dev
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&& client->slave->dma_dev != device->dev)
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continue;
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list_for_each_entry(chan, &device->channels, device_node) {
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if (!dma_chan_satisfies_mask(chan, client->cap_mask))
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continue;
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desc = chan->device->device_alloc_chan_resources(
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chan, client);
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if (desc >= 0) {
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ack = client->event_callback(client,
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chan,
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DMA_RESOURCE_AVAILABLE);
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/* we are done once this client rejects
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* an available resource
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*/
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if (ack == DMA_ACK) {
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dma_chan_get(chan);
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chan->client_count++;
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} else if (ack == DMA_NAK)
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return;
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}
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}
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}
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}
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enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
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{
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enum dma_status status;
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unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
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dma_async_issue_pending(chan);
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do {
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status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
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if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
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printk(KERN_ERR "dma_sync_wait_timeout!\n");
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return DMA_ERROR;
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}
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} while (status == DMA_IN_PROGRESS);
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return status;
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}
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EXPORT_SYMBOL(dma_sync_wait);
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/**
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* dma_chan_cleanup - release a DMA channel's resources
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* @kref: kernel reference structure that contains the DMA channel device
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*/
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void dma_chan_cleanup(struct kref *kref)
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{
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struct dma_chan *chan = container_of(kref, struct dma_chan, refcount);
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chan->device->device_free_chan_resources(chan);
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kref_put(&chan->device->refcount, dma_async_device_cleanup);
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}
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EXPORT_SYMBOL(dma_chan_cleanup);
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static void dma_chan_free_rcu(struct rcu_head *rcu)
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{
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struct dma_chan *chan = container_of(rcu, struct dma_chan, rcu);
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int bias = 0x7FFFFFFF;
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int i;
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for_each_possible_cpu(i)
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bias -= local_read(&per_cpu_ptr(chan->local, i)->refcount);
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atomic_sub(bias, &chan->refcount.refcount);
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kref_put(&chan->refcount, dma_chan_cleanup);
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}
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static void dma_chan_release(struct dma_chan *chan)
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{
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atomic_add(0x7FFFFFFF, &chan->refcount.refcount);
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chan->slow_ref = 1;
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call_rcu(&chan->rcu, dma_chan_free_rcu);
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}
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/**
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* dma_chans_notify_available - broadcast available channels to the clients
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*/
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static void dma_clients_notify_available(void)
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{
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struct dma_client *client;
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mutex_lock(&dma_list_mutex);
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list_for_each_entry(client, &dma_client_list, global_node)
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dma_client_chan_alloc(client);
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mutex_unlock(&dma_list_mutex);
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}
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/**
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* dma_chans_notify_available - tell the clients that a channel is going away
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* @chan: channel on its way out
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*/
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static void dma_clients_notify_removed(struct dma_chan *chan)
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{
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struct dma_client *client;
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enum dma_state_client ack;
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mutex_lock(&dma_list_mutex);
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list_for_each_entry(client, &dma_client_list, global_node) {
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ack = client->event_callback(client, chan,
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DMA_RESOURCE_REMOVED);
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/* client was holding resources for this channel so
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* free it
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*/
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if (ack == DMA_ACK) {
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dma_chan_put(chan);
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chan->client_count--;
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}
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}
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mutex_unlock(&dma_list_mutex);
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}
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/**
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* dma_async_client_register - register a &dma_client
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* @client: ptr to a client structure with valid 'event_callback' and 'cap_mask'
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*/
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void dma_async_client_register(struct dma_client *client)
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{
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/* validate client data */
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BUG_ON(dma_has_cap(DMA_SLAVE, client->cap_mask) &&
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!client->slave);
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mutex_lock(&dma_list_mutex);
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list_add_tail(&client->global_node, &dma_client_list);
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mutex_unlock(&dma_list_mutex);
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}
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EXPORT_SYMBOL(dma_async_client_register);
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/**
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* dma_async_client_unregister - unregister a client and free the &dma_client
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* @client: &dma_client to free
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*
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* Force frees any allocated DMA channels, frees the &dma_client memory
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*/
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void dma_async_client_unregister(struct dma_client *client)
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{
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struct dma_device *device;
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struct dma_chan *chan;
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enum dma_state_client ack;
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if (!client)
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return;
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mutex_lock(&dma_list_mutex);
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/* free all channels the client is holding */
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list_for_each_entry(device, &dma_device_list, global_node)
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list_for_each_entry(chan, &device->channels, device_node) {
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ack = client->event_callback(client, chan,
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DMA_RESOURCE_REMOVED);
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if (ack == DMA_ACK) {
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dma_chan_put(chan);
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chan->client_count--;
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}
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}
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list_del(&client->global_node);
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mutex_unlock(&dma_list_mutex);
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}
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EXPORT_SYMBOL(dma_async_client_unregister);
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/**
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* dma_async_client_chan_request - send all available channels to the
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* client that satisfy the capability mask
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* @client - requester
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*/
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void dma_async_client_chan_request(struct dma_client *client)
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{
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mutex_lock(&dma_list_mutex);
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dma_client_chan_alloc(client);
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mutex_unlock(&dma_list_mutex);
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}
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EXPORT_SYMBOL(dma_async_client_chan_request);
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/**
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* dma_async_device_register - registers DMA devices found
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* @device: &dma_device
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*/
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int dma_async_device_register(struct dma_device *device)
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{
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static int id;
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int chancnt = 0, rc;
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struct dma_chan* chan;
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if (!device)
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return -ENODEV;
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/* validate device routines */
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BUG_ON(dma_has_cap(DMA_MEMCPY, device->cap_mask) &&
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!device->device_prep_dma_memcpy);
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BUG_ON(dma_has_cap(DMA_XOR, device->cap_mask) &&
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!device->device_prep_dma_xor);
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BUG_ON(dma_has_cap(DMA_ZERO_SUM, device->cap_mask) &&
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!device->device_prep_dma_zero_sum);
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BUG_ON(dma_has_cap(DMA_MEMSET, device->cap_mask) &&
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!device->device_prep_dma_memset);
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BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) &&
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!device->device_prep_dma_interrupt);
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BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
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!device->device_prep_slave_sg);
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BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
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!device->device_terminate_all);
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BUG_ON(!device->device_alloc_chan_resources);
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BUG_ON(!device->device_free_chan_resources);
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BUG_ON(!device->device_is_tx_complete);
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BUG_ON(!device->device_issue_pending);
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BUG_ON(!device->dev);
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init_completion(&device->done);
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kref_init(&device->refcount);
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mutex_lock(&dma_list_mutex);
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device->dev_id = id++;
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mutex_unlock(&dma_list_mutex);
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/* represent channels in sysfs. Probably want devs too */
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list_for_each_entry(chan, &device->channels, device_node) {
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chan->local = alloc_percpu(typeof(*chan->local));
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if (chan->local == NULL)
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continue;
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chan->chan_id = chancnt++;
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chan->dev.class = &dma_devclass;
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chan->dev.parent = device->dev;
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dev_set_name(&chan->dev, "dma%dchan%d",
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device->dev_id, chan->chan_id);
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rc = device_register(&chan->dev);
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if (rc) {
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chancnt--;
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free_percpu(chan->local);
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chan->local = NULL;
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goto err_out;
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}
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/* One for the channel, one of the class device */
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kref_get(&device->refcount);
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kref_get(&device->refcount);
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kref_init(&chan->refcount);
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chan->client_count = 0;
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chan->slow_ref = 0;
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INIT_RCU_HEAD(&chan->rcu);
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}
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mutex_lock(&dma_list_mutex);
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list_add_tail(&device->global_node, &dma_device_list);
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mutex_unlock(&dma_list_mutex);
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dma_clients_notify_available();
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return 0;
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err_out:
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list_for_each_entry(chan, &device->channels, device_node) {
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if (chan->local == NULL)
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continue;
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kref_put(&device->refcount, dma_async_device_cleanup);
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device_unregister(&chan->dev);
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chancnt--;
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free_percpu(chan->local);
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}
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return rc;
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}
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EXPORT_SYMBOL(dma_async_device_register);
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/**
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* dma_async_device_cleanup - function called when all references are released
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* @kref: kernel reference object
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*/
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static void dma_async_device_cleanup(struct kref *kref)
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{
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struct dma_device *device;
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device = container_of(kref, struct dma_device, refcount);
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complete(&device->done);
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}
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/**
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* dma_async_device_unregister - unregisters DMA devices
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* @device: &dma_device
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*/
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void dma_async_device_unregister(struct dma_device *device)
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{
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struct dma_chan *chan;
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mutex_lock(&dma_list_mutex);
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list_del(&device->global_node);
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mutex_unlock(&dma_list_mutex);
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list_for_each_entry(chan, &device->channels, device_node) {
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dma_clients_notify_removed(chan);
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device_unregister(&chan->dev);
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dma_chan_release(chan);
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}
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kref_put(&device->refcount, dma_async_device_cleanup);
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wait_for_completion(&device->done);
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}
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EXPORT_SYMBOL(dma_async_device_unregister);
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/**
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* dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
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* @chan: DMA channel to offload copy to
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* @dest: destination address (virtual)
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* @src: source address (virtual)
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* @len: length
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*
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* Both @dest and @src must be mappable to a bus address according to the
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* DMA mapping API rules for streaming mappings.
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* Both @dest and @src must stay memory resident (kernel memory or locked
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* user space pages).
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*/
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dma_cookie_t
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dma_async_memcpy_buf_to_buf(struct dma_chan *chan, void *dest,
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void *src, size_t len)
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{
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struct dma_device *dev = chan->device;
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|
struct dma_async_tx_descriptor *tx;
|
|
dma_addr_t dma_dest, dma_src;
|
|
dma_cookie_t cookie;
|
|
int cpu;
|
|
|
|
dma_src = dma_map_single(dev->dev, src, len, DMA_TO_DEVICE);
|
|
dma_dest = dma_map_single(dev->dev, dest, len, DMA_FROM_DEVICE);
|
|
tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len,
|
|
DMA_CTRL_ACK);
|
|
|
|
if (!tx) {
|
|
dma_unmap_single(dev->dev, dma_src, len, DMA_TO_DEVICE);
|
|
dma_unmap_single(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
tx->callback = NULL;
|
|
cookie = tx->tx_submit(tx);
|
|
|
|
cpu = get_cpu();
|
|
per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
|
|
per_cpu_ptr(chan->local, cpu)->memcpy_count++;
|
|
put_cpu();
|
|
|
|
return cookie;
|
|
}
|
|
EXPORT_SYMBOL(dma_async_memcpy_buf_to_buf);
|
|
|
|
/**
|
|
* dma_async_memcpy_buf_to_pg - offloaded copy from address to page
|
|
* @chan: DMA channel to offload copy to
|
|
* @page: destination page
|
|
* @offset: offset in page to copy to
|
|
* @kdata: source address (virtual)
|
|
* @len: length
|
|
*
|
|
* Both @page/@offset and @kdata must be mappable to a bus address according
|
|
* to the DMA mapping API rules for streaming mappings.
|
|
* Both @page/@offset and @kdata must stay memory resident (kernel memory or
|
|
* locked user space pages)
|
|
*/
|
|
dma_cookie_t
|
|
dma_async_memcpy_buf_to_pg(struct dma_chan *chan, struct page *page,
|
|
unsigned int offset, void *kdata, size_t len)
|
|
{
|
|
struct dma_device *dev = chan->device;
|
|
struct dma_async_tx_descriptor *tx;
|
|
dma_addr_t dma_dest, dma_src;
|
|
dma_cookie_t cookie;
|
|
int cpu;
|
|
|
|
dma_src = dma_map_single(dev->dev, kdata, len, DMA_TO_DEVICE);
|
|
dma_dest = dma_map_page(dev->dev, page, offset, len, DMA_FROM_DEVICE);
|
|
tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len,
|
|
DMA_CTRL_ACK);
|
|
|
|
if (!tx) {
|
|
dma_unmap_single(dev->dev, dma_src, len, DMA_TO_DEVICE);
|
|
dma_unmap_page(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
tx->callback = NULL;
|
|
cookie = tx->tx_submit(tx);
|
|
|
|
cpu = get_cpu();
|
|
per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
|
|
per_cpu_ptr(chan->local, cpu)->memcpy_count++;
|
|
put_cpu();
|
|
|
|
return cookie;
|
|
}
|
|
EXPORT_SYMBOL(dma_async_memcpy_buf_to_pg);
|
|
|
|
/**
|
|
* dma_async_memcpy_pg_to_pg - offloaded copy from page to page
|
|
* @chan: DMA channel to offload copy to
|
|
* @dest_pg: destination page
|
|
* @dest_off: offset in page to copy to
|
|
* @src_pg: source page
|
|
* @src_off: offset in page to copy from
|
|
* @len: length
|
|
*
|
|
* Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
|
|
* address according to the DMA mapping API rules for streaming mappings.
|
|
* Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
|
|
* (kernel memory or locked user space pages).
|
|
*/
|
|
dma_cookie_t
|
|
dma_async_memcpy_pg_to_pg(struct dma_chan *chan, struct page *dest_pg,
|
|
unsigned int dest_off, struct page *src_pg, unsigned int src_off,
|
|
size_t len)
|
|
{
|
|
struct dma_device *dev = chan->device;
|
|
struct dma_async_tx_descriptor *tx;
|
|
dma_addr_t dma_dest, dma_src;
|
|
dma_cookie_t cookie;
|
|
int cpu;
|
|
|
|
dma_src = dma_map_page(dev->dev, src_pg, src_off, len, DMA_TO_DEVICE);
|
|
dma_dest = dma_map_page(dev->dev, dest_pg, dest_off, len,
|
|
DMA_FROM_DEVICE);
|
|
tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len,
|
|
DMA_CTRL_ACK);
|
|
|
|
if (!tx) {
|
|
dma_unmap_page(dev->dev, dma_src, len, DMA_TO_DEVICE);
|
|
dma_unmap_page(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
tx->callback = NULL;
|
|
cookie = tx->tx_submit(tx);
|
|
|
|
cpu = get_cpu();
|
|
per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
|
|
per_cpu_ptr(chan->local, cpu)->memcpy_count++;
|
|
put_cpu();
|
|
|
|
return cookie;
|
|
}
|
|
EXPORT_SYMBOL(dma_async_memcpy_pg_to_pg);
|
|
|
|
void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
|
|
struct dma_chan *chan)
|
|
{
|
|
tx->chan = chan;
|
|
spin_lock_init(&tx->lock);
|
|
}
|
|
EXPORT_SYMBOL(dma_async_tx_descriptor_init);
|
|
|
|
static int __init dma_bus_init(void)
|
|
{
|
|
mutex_init(&dma_list_mutex);
|
|
return class_register(&dma_devclass);
|
|
}
|
|
subsys_initcall(dma_bus_init);
|
|
|