2 * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License as published by the Free
6 * Software Foundation; either version 2 of the License, or (at your option)
9 * This program is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14 * You should have received a copy of the GNU General Public License along with
15 * this program; if not, write to the Free Software Foundation, Inc., 59
16 * Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 * The full GNU General Public License is included in this distribution in the
19 * file called COPYING.
23 * This code implements the DMA subsystem. It provides a HW-neutral interface
24 * for other kernel code to use asynchronous memory copy capabilities,
25 * if present, and allows different HW DMA drivers to register as providing
28 * Due to the fact we are accelerating what is already a relatively fast
29 * operation, the code goes to great lengths to avoid additional overhead,
34 * The subsystem keeps a global list of dma_device structs it is protected by a
35 * mutex, dma_list_mutex.
37 * A subsystem can get access to a channel by calling dmaengine_get() followed
38 * by dma_find_channel(), or if it has need for an exclusive channel it can call
39 * dma_request_channel(). Once a channel is allocated a reference is taken
40 * against its corresponding driver to disable removal.
42 * Each device has a channels list, which runs unlocked but is never modified
43 * once the device is registered, it's just setup by the driver.
45 * See Documentation/dmaengine.txt for more details
48 #include <linux/init.h>
49 #include <linux/module.h>
51 #include <linux/device.h>
52 #include <linux/dmaengine.h>
53 #include <linux/hardirq.h>
54 #include <linux/spinlock.h>
55 #include <linux/percpu.h>
56 #include <linux/rcupdate.h>
57 #include <linux/mutex.h>
58 #include <linux/jiffies.h>
59 #include <linux/rculist.h>
60 #include <linux/idr.h>
62 static DEFINE_MUTEX(dma_list_mutex);
63 static LIST_HEAD(dma_device_list);
64 static long dmaengine_ref_count;
65 static struct idr dma_idr;
67 /* --- sysfs implementation --- */
70 * dev_to_dma_chan - convert a device pointer to the its sysfs container object
73 * Must be called under dma_list_mutex
75 static struct dma_chan *dev_to_dma_chan(struct device *dev)
77 struct dma_chan_dev *chan_dev;
79 chan_dev = container_of(dev, typeof(*chan_dev), device);
80 return chan_dev->chan;
83 static ssize_t show_memcpy_count(struct device *dev, struct device_attribute *attr, char *buf)
85 struct dma_chan *chan;
86 unsigned long count = 0;
90 mutex_lock(&dma_list_mutex);
91 chan = dev_to_dma_chan(dev);
93 for_each_possible_cpu(i)
94 count += per_cpu_ptr(chan->local, i)->memcpy_count;
95 err = sprintf(buf, "%lu\n", count);
98 mutex_unlock(&dma_list_mutex);
103 static ssize_t show_bytes_transferred(struct device *dev, struct device_attribute *attr,
106 struct dma_chan *chan;
107 unsigned long count = 0;
111 mutex_lock(&dma_list_mutex);
112 chan = dev_to_dma_chan(dev);
114 for_each_possible_cpu(i)
115 count += per_cpu_ptr(chan->local, i)->bytes_transferred;
116 err = sprintf(buf, "%lu\n", count);
119 mutex_unlock(&dma_list_mutex);
124 static ssize_t show_in_use(struct device *dev, struct device_attribute *attr, char *buf)
126 struct dma_chan *chan;
129 mutex_lock(&dma_list_mutex);
130 chan = dev_to_dma_chan(dev);
132 err = sprintf(buf, "%d\n", chan->client_count);
135 mutex_unlock(&dma_list_mutex);
140 static struct device_attribute dma_attrs[] = {
141 __ATTR(memcpy_count, S_IRUGO, show_memcpy_count, NULL),
142 __ATTR(bytes_transferred, S_IRUGO, show_bytes_transferred, NULL),
143 __ATTR(in_use, S_IRUGO, show_in_use, NULL),
147 static void chan_dev_release(struct device *dev)
149 struct dma_chan_dev *chan_dev;
151 chan_dev = container_of(dev, typeof(*chan_dev), device);
152 if (atomic_dec_and_test(chan_dev->idr_ref)) {
153 mutex_lock(&dma_list_mutex);
154 idr_remove(&dma_idr, chan_dev->dev_id);
155 mutex_unlock(&dma_list_mutex);
156 kfree(chan_dev->idr_ref);
161 static struct class dma_devclass = {
163 .dev_attrs = dma_attrs,
164 .dev_release = chan_dev_release,
167 /* --- client and device registration --- */
169 #define dma_device_satisfies_mask(device, mask) \
170 __dma_device_satisfies_mask((device), &(mask))
172 __dma_device_satisfies_mask(struct dma_device *device, dma_cap_mask_t *want)
176 bitmap_and(has.bits, want->bits, device->cap_mask.bits,
178 return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END);
181 static struct module *dma_chan_to_owner(struct dma_chan *chan)
183 return chan->device->dev->driver->owner;
187 * balance_ref_count - catch up the channel reference count
188 * @chan - channel to balance ->client_count versus dmaengine_ref_count
190 * balance_ref_count must be called under dma_list_mutex
192 static void balance_ref_count(struct dma_chan *chan)
194 struct module *owner = dma_chan_to_owner(chan);
196 while (chan->client_count < dmaengine_ref_count) {
198 chan->client_count++;
203 * dma_chan_get - try to grab a dma channel's parent driver module
204 * @chan - channel to grab
206 * Must be called under dma_list_mutex
208 static int dma_chan_get(struct dma_chan *chan)
211 struct module *owner = dma_chan_to_owner(chan);
213 if (chan->client_count) {
216 } else if (try_module_get(owner))
220 chan->client_count++;
222 /* allocate upon first client reference */
223 if (chan->client_count == 1 && err == 0) {
224 int desc_cnt = chan->device->device_alloc_chan_resources(chan);
228 chan->client_count = 0;
230 } else if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
231 balance_ref_count(chan);
238 * dma_chan_put - drop a reference to a dma channel's parent driver module
239 * @chan - channel to release
241 * Must be called under dma_list_mutex
243 static void dma_chan_put(struct dma_chan *chan)
245 if (!chan->client_count)
246 return; /* this channel failed alloc_chan_resources */
247 chan->client_count--;
248 module_put(dma_chan_to_owner(chan));
249 if (chan->client_count == 0)
250 chan->device->device_free_chan_resources(chan);
253 enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
255 enum dma_status status;
256 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
258 dma_async_issue_pending(chan);
260 status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
261 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
262 printk(KERN_ERR "dma_sync_wait_timeout!\n");
265 } while (status == DMA_IN_PROGRESS);
269 EXPORT_SYMBOL(dma_sync_wait);
272 * dma_cap_mask_all - enable iteration over all operation types
274 static dma_cap_mask_t dma_cap_mask_all;
277 * dma_chan_tbl_ent - tracks channel allocations per core/operation
278 * @chan - associated channel for this entry
280 struct dma_chan_tbl_ent {
281 struct dma_chan *chan;
285 * channel_table - percpu lookup table for memory-to-memory offload providers
287 static struct dma_chan_tbl_ent *channel_table[DMA_TX_TYPE_END];
289 static int __init dma_channel_table_init(void)
291 enum dma_transaction_type cap;
294 bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END);
296 /* 'interrupt', 'private', and 'slave' are channel capabilities,
297 * but are not associated with an operation so they do not need
298 * an entry in the channel_table
300 clear_bit(DMA_INTERRUPT, dma_cap_mask_all.bits);
301 clear_bit(DMA_PRIVATE, dma_cap_mask_all.bits);
302 clear_bit(DMA_SLAVE, dma_cap_mask_all.bits);
304 for_each_dma_cap_mask(cap, dma_cap_mask_all) {
305 channel_table[cap] = alloc_percpu(struct dma_chan_tbl_ent);
306 if (!channel_table[cap]) {
313 pr_err("dmaengine: initialization failure\n");
314 for_each_dma_cap_mask(cap, dma_cap_mask_all)
315 if (channel_table[cap])
316 free_percpu(channel_table[cap]);
321 arch_initcall(dma_channel_table_init);
324 * dma_find_channel - find a channel to carry out the operation
325 * @tx_type: transaction type
327 struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
329 struct dma_chan *chan;
333 chan = per_cpu_ptr(channel_table[tx_type], cpu)->chan;
338 EXPORT_SYMBOL(dma_find_channel);
341 * dma_issue_pending_all - flush all pending operations across all channels
343 void dma_issue_pending_all(void)
345 struct dma_device *device;
346 struct dma_chan *chan;
349 list_for_each_entry_rcu(device, &dma_device_list, global_node) {
350 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
352 list_for_each_entry(chan, &device->channels, device_node)
353 if (chan->client_count)
354 device->device_issue_pending(chan);
358 EXPORT_SYMBOL(dma_issue_pending_all);
361 * nth_chan - returns the nth channel of the given capability
362 * @cap: capability to match
363 * @n: nth channel desired
365 * Defaults to returning the channel with the desired capability and the
366 * lowest reference count when 'n' cannot be satisfied. Must be called
367 * under dma_list_mutex.
369 static struct dma_chan *nth_chan(enum dma_transaction_type cap, int n)
371 struct dma_device *device;
372 struct dma_chan *chan;
373 struct dma_chan *ret = NULL;
374 struct dma_chan *min = NULL;
376 list_for_each_entry(device, &dma_device_list, global_node) {
377 if (!dma_has_cap(cap, device->cap_mask) ||
378 dma_has_cap(DMA_PRIVATE, device->cap_mask))
380 list_for_each_entry(chan, &device->channels, device_node) {
381 if (!chan->client_count)
385 else if (chan->table_count < min->table_count)
407 * dma_channel_rebalance - redistribute the available channels
409 * Optimize for cpu isolation (each cpu gets a dedicated channel for an
410 * operation type) in the SMP case, and operation isolation (avoid
411 * multi-tasking channels) in the non-SMP case. Must be called under
414 static void dma_channel_rebalance(void)
416 struct dma_chan *chan;
417 struct dma_device *device;
422 /* undo the last distribution */
423 for_each_dma_cap_mask(cap, dma_cap_mask_all)
424 for_each_possible_cpu(cpu)
425 per_cpu_ptr(channel_table[cap], cpu)->chan = NULL;
427 list_for_each_entry(device, &dma_device_list, global_node) {
428 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
430 list_for_each_entry(chan, &device->channels, device_node)
431 chan->table_count = 0;
434 /* don't populate the channel_table if no clients are available */
435 if (!dmaengine_ref_count)
438 /* redistribute available channels */
440 for_each_dma_cap_mask(cap, dma_cap_mask_all)
441 for_each_online_cpu(cpu) {
442 if (num_possible_cpus() > 1)
443 chan = nth_chan(cap, n++);
445 chan = nth_chan(cap, -1);
447 per_cpu_ptr(channel_table[cap], cpu)->chan = chan;
451 static struct dma_chan *private_candidate(dma_cap_mask_t *mask, struct dma_device *dev,
452 dma_filter_fn fn, void *fn_param)
454 struct dma_chan *chan;
456 if (!__dma_device_satisfies_mask(dev, mask)) {
457 pr_debug("%s: wrong capabilities\n", __func__);
460 /* devices with multiple channels need special handling as we need to
461 * ensure that all channels are either private or public.
463 if (dev->chancnt > 1 && !dma_has_cap(DMA_PRIVATE, dev->cap_mask))
464 list_for_each_entry(chan, &dev->channels, device_node) {
465 /* some channels are already publicly allocated */
466 if (chan->client_count)
470 list_for_each_entry(chan, &dev->channels, device_node) {
471 if (chan->client_count) {
472 pr_debug("%s: %s busy\n",
473 __func__, dma_chan_name(chan));
476 if (fn && !fn(chan, fn_param)) {
477 pr_debug("%s: %s filter said false\n",
478 __func__, dma_chan_name(chan));
488 * dma_request_channel - try to allocate an exclusive channel
489 * @mask: capabilities that the channel must satisfy
490 * @fn: optional callback to disposition available channels
491 * @fn_param: opaque parameter to pass to dma_filter_fn
493 struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, void *fn_param)
495 struct dma_device *device, *_d;
496 struct dma_chan *chan = NULL;
500 mutex_lock(&dma_list_mutex);
501 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
502 chan = private_candidate(mask, device, fn, fn_param);
504 /* Found a suitable channel, try to grab, prep, and
505 * return it. We first set DMA_PRIVATE to disable
506 * balance_ref_count as this channel will not be
507 * published in the general-purpose allocator
509 dma_cap_set(DMA_PRIVATE, device->cap_mask);
510 err = dma_chan_get(chan);
512 if (err == -ENODEV) {
513 pr_debug("%s: %s module removed\n", __func__,
514 dma_chan_name(chan));
515 list_del_rcu(&device->global_node);
517 pr_err("dmaengine: failed to get %s: (%d)\n",
518 dma_chan_name(chan), err);
521 chan->private = NULL;
525 mutex_unlock(&dma_list_mutex);
527 pr_debug("%s: %s (%s)\n", __func__, chan ? "success" : "fail",
528 chan ? dma_chan_name(chan) : NULL);
532 EXPORT_SYMBOL_GPL(__dma_request_channel);
534 void dma_release_channel(struct dma_chan *chan)
536 mutex_lock(&dma_list_mutex);
537 WARN_ONCE(chan->client_count != 1,
538 "chan reference count %d != 1\n", chan->client_count);
540 chan->private = NULL;
541 mutex_unlock(&dma_list_mutex);
543 EXPORT_SYMBOL_GPL(dma_release_channel);
546 * dmaengine_get - register interest in dma_channels
548 void dmaengine_get(void)
550 struct dma_device *device, *_d;
551 struct dma_chan *chan;
554 mutex_lock(&dma_list_mutex);
555 dmaengine_ref_count++;
557 /* try to grab channels */
558 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
559 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
561 list_for_each_entry(chan, &device->channels, device_node) {
562 err = dma_chan_get(chan);
563 if (err == -ENODEV) {
564 /* module removed before we could use it */
565 list_del_rcu(&device->global_node);
568 pr_err("dmaengine: failed to get %s: (%d)\n",
569 dma_chan_name(chan), err);
573 /* if this is the first reference and there were channels
574 * waiting we need to rebalance to get those channels
575 * incorporated into the channel table
577 if (dmaengine_ref_count == 1)
578 dma_channel_rebalance();
579 mutex_unlock(&dma_list_mutex);
581 EXPORT_SYMBOL(dmaengine_get);
584 * dmaengine_put - let dma drivers be removed when ref_count == 0
586 void dmaengine_put(void)
588 struct dma_device *device;
589 struct dma_chan *chan;
591 mutex_lock(&dma_list_mutex);
592 dmaengine_ref_count--;
593 BUG_ON(dmaengine_ref_count < 0);
594 /* drop channel references */
595 list_for_each_entry(device, &dma_device_list, global_node) {
596 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
598 list_for_each_entry(chan, &device->channels, device_node)
601 mutex_unlock(&dma_list_mutex);
603 EXPORT_SYMBOL(dmaengine_put);
605 static int get_dma_id(struct dma_device *device)
610 if (!idr_pre_get(&dma_idr, GFP_KERNEL))
612 mutex_lock(&dma_list_mutex);
613 rc = idr_get_new(&dma_idr, NULL, &device->dev_id);
614 mutex_unlock(&dma_list_mutex);
624 * dma_async_device_register - registers DMA devices found
625 * @device: &dma_device
627 int dma_async_device_register(struct dma_device *device)
630 struct dma_chan* chan;
636 /* validate device routines */
637 BUG_ON(dma_has_cap(DMA_MEMCPY, device->cap_mask) &&
638 !device->device_prep_dma_memcpy);
639 BUG_ON(dma_has_cap(DMA_XOR, device->cap_mask) &&
640 !device->device_prep_dma_xor);
641 BUG_ON(dma_has_cap(DMA_ZERO_SUM, device->cap_mask) &&
642 !device->device_prep_dma_zero_sum);
643 BUG_ON(dma_has_cap(DMA_MEMSET, device->cap_mask) &&
644 !device->device_prep_dma_memset);
645 BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) &&
646 !device->device_prep_dma_interrupt);
647 BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
648 !device->device_prep_slave_sg);
649 BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
650 !device->device_terminate_all);
652 BUG_ON(!device->device_alloc_chan_resources);
653 BUG_ON(!device->device_free_chan_resources);
654 BUG_ON(!device->device_is_tx_complete);
655 BUG_ON(!device->device_issue_pending);
656 BUG_ON(!device->dev);
658 idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL);
661 rc = get_dma_id(device);
667 atomic_set(idr_ref, 0);
669 /* represent channels in sysfs. Probably want devs too */
670 list_for_each_entry(chan, &device->channels, device_node) {
672 chan->local = alloc_percpu(typeof(*chan->local));
673 if (chan->local == NULL)
675 chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
676 if (chan->dev == NULL) {
677 free_percpu(chan->local);
682 chan->chan_id = chancnt++;
683 chan->dev->device.class = &dma_devclass;
684 chan->dev->device.parent = device->dev;
685 chan->dev->chan = chan;
686 chan->dev->idr_ref = idr_ref;
687 chan->dev->dev_id = device->dev_id;
689 dev_set_name(&chan->dev->device, "dma%dchan%d",
690 device->dev_id, chan->chan_id);
692 rc = device_register(&chan->dev->device);
694 free_percpu(chan->local);
700 chan->client_count = 0;
702 device->chancnt = chancnt;
704 mutex_lock(&dma_list_mutex);
705 /* take references on public channels */
706 if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
707 list_for_each_entry(chan, &device->channels, device_node) {
708 /* if clients are already waiting for channels we need
709 * to take references on their behalf
711 if (dma_chan_get(chan) == -ENODEV) {
712 /* note we can only get here for the first
713 * channel as the remaining channels are
714 * guaranteed to get a reference
717 mutex_unlock(&dma_list_mutex);
721 list_add_tail_rcu(&device->global_node, &dma_device_list);
722 dma_channel_rebalance();
723 mutex_unlock(&dma_list_mutex);
728 /* if we never registered a channel just release the idr */
729 if (atomic_read(idr_ref) == 0) {
730 mutex_lock(&dma_list_mutex);
731 idr_remove(&dma_idr, device->dev_id);
732 mutex_unlock(&dma_list_mutex);
737 list_for_each_entry(chan, &device->channels, device_node) {
738 if (chan->local == NULL)
740 mutex_lock(&dma_list_mutex);
741 chan->dev->chan = NULL;
742 mutex_unlock(&dma_list_mutex);
743 device_unregister(&chan->dev->device);
744 free_percpu(chan->local);
748 EXPORT_SYMBOL(dma_async_device_register);
751 * dma_async_device_unregister - unregister a DMA device
752 * @device: &dma_device
754 * This routine is called by dma driver exit routines, dmaengine holds module
755 * references to prevent it being called while channels are in use.
757 void dma_async_device_unregister(struct dma_device *device)
759 struct dma_chan *chan;
761 mutex_lock(&dma_list_mutex);
762 list_del_rcu(&device->global_node);
763 dma_channel_rebalance();
764 mutex_unlock(&dma_list_mutex);
766 list_for_each_entry(chan, &device->channels, device_node) {
767 WARN_ONCE(chan->client_count,
768 "%s called while %d clients hold a reference\n",
769 __func__, chan->client_count);
770 mutex_lock(&dma_list_mutex);
771 chan->dev->chan = NULL;
772 mutex_unlock(&dma_list_mutex);
773 device_unregister(&chan->dev->device);
776 EXPORT_SYMBOL(dma_async_device_unregister);
779 * dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
780 * @chan: DMA channel to offload copy to
781 * @dest: destination address (virtual)
782 * @src: source address (virtual)
785 * Both @dest and @src must be mappable to a bus address according to the
786 * DMA mapping API rules for streaming mappings.
787 * Both @dest and @src must stay memory resident (kernel memory or locked
791 dma_async_memcpy_buf_to_buf(struct dma_chan *chan, void *dest,
792 void *src, size_t len)
794 struct dma_device *dev = chan->device;
795 struct dma_async_tx_descriptor *tx;
796 dma_addr_t dma_dest, dma_src;
800 dma_src = dma_map_single(dev->dev, src, len, DMA_TO_DEVICE);
801 dma_dest = dma_map_single(dev->dev, dest, len, DMA_FROM_DEVICE);
802 tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len,
806 dma_unmap_single(dev->dev, dma_src, len, DMA_TO_DEVICE);
807 dma_unmap_single(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
812 cookie = tx->tx_submit(tx);
815 per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
816 per_cpu_ptr(chan->local, cpu)->memcpy_count++;
821 EXPORT_SYMBOL(dma_async_memcpy_buf_to_buf);
824 * dma_async_memcpy_buf_to_pg - offloaded copy from address to page
825 * @chan: DMA channel to offload copy to
826 * @page: destination page
827 * @offset: offset in page to copy to
828 * @kdata: source address (virtual)
831 * Both @page/@offset and @kdata must be mappable to a bus address according
832 * to the DMA mapping API rules for streaming mappings.
833 * Both @page/@offset and @kdata must stay memory resident (kernel memory or
834 * locked user space pages)
837 dma_async_memcpy_buf_to_pg(struct dma_chan *chan, struct page *page,
838 unsigned int offset, void *kdata, size_t len)
840 struct dma_device *dev = chan->device;
841 struct dma_async_tx_descriptor *tx;
842 dma_addr_t dma_dest, dma_src;
846 dma_src = dma_map_single(dev->dev, kdata, len, DMA_TO_DEVICE);
847 dma_dest = dma_map_page(dev->dev, page, offset, len, DMA_FROM_DEVICE);
848 tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len,
852 dma_unmap_single(dev->dev, dma_src, len, DMA_TO_DEVICE);
853 dma_unmap_page(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
858 cookie = tx->tx_submit(tx);
861 per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
862 per_cpu_ptr(chan->local, cpu)->memcpy_count++;
867 EXPORT_SYMBOL(dma_async_memcpy_buf_to_pg);
870 * dma_async_memcpy_pg_to_pg - offloaded copy from page to page
871 * @chan: DMA channel to offload copy to
872 * @dest_pg: destination page
873 * @dest_off: offset in page to copy to
874 * @src_pg: source page
875 * @src_off: offset in page to copy from
878 * Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
879 * address according to the DMA mapping API rules for streaming mappings.
880 * Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
881 * (kernel memory or locked user space pages).
884 dma_async_memcpy_pg_to_pg(struct dma_chan *chan, struct page *dest_pg,
885 unsigned int dest_off, struct page *src_pg, unsigned int src_off,
888 struct dma_device *dev = chan->device;
889 struct dma_async_tx_descriptor *tx;
890 dma_addr_t dma_dest, dma_src;
894 dma_src = dma_map_page(dev->dev, src_pg, src_off, len, DMA_TO_DEVICE);
895 dma_dest = dma_map_page(dev->dev, dest_pg, dest_off, len,
897 tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len,
901 dma_unmap_page(dev->dev, dma_src, len, DMA_TO_DEVICE);
902 dma_unmap_page(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
907 cookie = tx->tx_submit(tx);
910 per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
911 per_cpu_ptr(chan->local, cpu)->memcpy_count++;
916 EXPORT_SYMBOL(dma_async_memcpy_pg_to_pg);
918 void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
919 struct dma_chan *chan)
922 spin_lock_init(&tx->lock);
923 INIT_LIST_HEAD(&tx->tx_list);
925 EXPORT_SYMBOL(dma_async_tx_descriptor_init);
927 /* dma_wait_for_async_tx - spin wait for a transaction to complete
928 * @tx: in-flight transaction to wait on
930 * This routine assumes that tx was obtained from a call to async_memcpy,
931 * async_xor, async_memset, etc which ensures that tx is "in-flight" (prepped
932 * and submitted). Walking the parent chain is only meant to cover for DMA
933 * drivers that do not implement the DMA_INTERRUPT capability and may race with
934 * the driver's descriptor cleanup routine.
937 dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
939 enum dma_status status;
940 struct dma_async_tx_descriptor *iter;
941 struct dma_async_tx_descriptor *parent;
946 WARN_ONCE(tx->parent, "%s: speculatively walking dependency chain for"
947 " %s\n", __func__, dma_chan_name(tx->chan));
949 /* poll through the dependency chain, return when tx is complete */
953 /* find the root of the unsubmitted dependency chain */
955 parent = iter->parent;
962 /* there is a small window for ->parent == NULL and
965 while (iter->cookie == -EBUSY)
968 status = dma_sync_wait(iter->chan, iter->cookie);
969 } while (status == DMA_IN_PROGRESS || (iter != tx));
973 EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
975 /* dma_run_dependencies - helper routine for dma drivers to process
976 * (start) dependent operations on their target channel
977 * @tx: transaction with dependencies
979 void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
981 struct dma_async_tx_descriptor *dep = tx->next;
982 struct dma_async_tx_descriptor *dep_next;
983 struct dma_chan *chan;
988 /* we'll submit tx->next now, so clear the link */
992 /* keep submitting up until a channel switch is detected
993 * in that case we will be called again as a result of
994 * processing the interrupt from async_tx_channel_switch
996 for (; dep; dep = dep_next) {
997 spin_lock_bh(&dep->lock);
999 dep_next = dep->next;
1000 if (dep_next && dep_next->chan == chan)
1001 dep->next = NULL; /* ->next will be submitted */
1003 dep_next = NULL; /* submit current dep and terminate */
1004 spin_unlock_bh(&dep->lock);
1006 dep->tx_submit(dep);
1009 chan->device->device_issue_pending(chan);
1011 EXPORT_SYMBOL_GPL(dma_run_dependencies);
1013 static int __init dma_bus_init(void)
1016 mutex_init(&dma_list_mutex);
1017 return class_register(&dma_devclass);
1019 arch_initcall(dma_bus_init);