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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
50 #include <linux/dma-mapping.h>
51 #include <linux/init.h>
52 #include <linux/module.h>
54 #include <linux/device.h>
55 #include <linux/dmaengine.h>
56 #include <linux/hardirq.h>
57 #include <linux/spinlock.h>
58 #include <linux/percpu.h>
59 #include <linux/rcupdate.h>
60 #include <linux/mutex.h>
61 #include <linux/jiffies.h>
62 #include <linux/rculist.h>
63 #include <linux/idr.h>
64 #include <linux/slab.h>
65 #include <linux/acpi.h>
66 #include <linux/acpi_dma.h>
67 #include <linux/of_dma.h>
69 static DEFINE_MUTEX(dma_list_mutex);
70 static DEFINE_IDR(dma_idr);
71 static LIST_HEAD(dma_device_list);
72 static long dmaengine_ref_count;
74 /* --- sysfs implementation --- */
77 * dev_to_dma_chan - convert a device pointer to the its sysfs container object
80 * Must be called under dma_list_mutex
82 static struct dma_chan *dev_to_dma_chan(struct device *dev)
84 struct dma_chan_dev *chan_dev;
86 chan_dev = container_of(dev, typeof(*chan_dev), device);
87 return chan_dev->chan;
90 static ssize_t memcpy_count_show(struct device *dev,
91 struct device_attribute *attr, char *buf)
93 struct dma_chan *chan;
94 unsigned long count = 0;
98 mutex_lock(&dma_list_mutex);
99 chan = dev_to_dma_chan(dev);
101 for_each_possible_cpu(i)
102 count += per_cpu_ptr(chan->local, i)->memcpy_count;
103 err = sprintf(buf, "%lu\n", count);
106 mutex_unlock(&dma_list_mutex);
110 static DEVICE_ATTR_RO(memcpy_count);
112 static ssize_t bytes_transferred_show(struct device *dev,
113 struct device_attribute *attr, char *buf)
115 struct dma_chan *chan;
116 unsigned long count = 0;
120 mutex_lock(&dma_list_mutex);
121 chan = dev_to_dma_chan(dev);
123 for_each_possible_cpu(i)
124 count += per_cpu_ptr(chan->local, i)->bytes_transferred;
125 err = sprintf(buf, "%lu\n", count);
128 mutex_unlock(&dma_list_mutex);
132 static DEVICE_ATTR_RO(bytes_transferred);
134 static ssize_t in_use_show(struct device *dev, struct device_attribute *attr,
137 struct dma_chan *chan;
140 mutex_lock(&dma_list_mutex);
141 chan = dev_to_dma_chan(dev);
143 err = sprintf(buf, "%d\n", chan->client_count);
146 mutex_unlock(&dma_list_mutex);
150 static DEVICE_ATTR_RO(in_use);
152 static struct attribute *dma_dev_attrs[] = {
153 &dev_attr_memcpy_count.attr,
154 &dev_attr_bytes_transferred.attr,
155 &dev_attr_in_use.attr,
158 ATTRIBUTE_GROUPS(dma_dev);
160 static void chan_dev_release(struct device *dev)
162 struct dma_chan_dev *chan_dev;
164 chan_dev = container_of(dev, typeof(*chan_dev), device);
165 if (atomic_dec_and_test(chan_dev->idr_ref)) {
166 mutex_lock(&dma_list_mutex);
167 idr_remove(&dma_idr, chan_dev->dev_id);
168 mutex_unlock(&dma_list_mutex);
169 kfree(chan_dev->idr_ref);
174 static struct class dma_devclass = {
176 .dev_groups = dma_dev_groups,
177 .dev_release = chan_dev_release,
180 /* --- client and device registration --- */
182 #define dma_device_satisfies_mask(device, mask) \
183 __dma_device_satisfies_mask((device), &(mask))
185 __dma_device_satisfies_mask(struct dma_device *device,
186 const dma_cap_mask_t *want)
190 bitmap_and(has.bits, want->bits, device->cap_mask.bits,
192 return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END);
195 static struct module *dma_chan_to_owner(struct dma_chan *chan)
197 return chan->device->dev->driver->owner;
201 * balance_ref_count - catch up the channel reference count
202 * @chan - channel to balance ->client_count versus dmaengine_ref_count
204 * balance_ref_count must be called under dma_list_mutex
206 static void balance_ref_count(struct dma_chan *chan)
208 struct module *owner = dma_chan_to_owner(chan);
210 while (chan->client_count < dmaengine_ref_count) {
212 chan->client_count++;
217 * dma_chan_get - try to grab a dma channel's parent driver module
218 * @chan - channel to grab
220 * Must be called under dma_list_mutex
222 static int dma_chan_get(struct dma_chan *chan)
225 struct module *owner = dma_chan_to_owner(chan);
227 if (chan->client_count) {
230 } else if (try_module_get(owner))
234 chan->client_count++;
236 /* allocate upon first client reference */
237 if (chan->client_count == 1 && err == 0) {
238 int desc_cnt = chan->device->device_alloc_chan_resources(chan);
242 chan->client_count = 0;
244 } else if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
245 balance_ref_count(chan);
252 * dma_chan_put - drop a reference to a dma channel's parent driver module
253 * @chan - channel to release
255 * Must be called under dma_list_mutex
257 static void dma_chan_put(struct dma_chan *chan)
259 if (!chan->client_count)
260 return; /* this channel failed alloc_chan_resources */
261 chan->client_count--;
262 module_put(dma_chan_to_owner(chan));
263 if (chan->client_count == 0)
264 chan->device->device_free_chan_resources(chan);
267 enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
269 enum dma_status status;
270 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
272 dma_async_issue_pending(chan);
274 status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
275 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
276 pr_err("%s: timeout!\n", __func__);
279 if (status != DMA_IN_PROGRESS)
286 EXPORT_SYMBOL(dma_sync_wait);
289 * dma_cap_mask_all - enable iteration over all operation types
291 static dma_cap_mask_t dma_cap_mask_all;
294 * dma_chan_tbl_ent - tracks channel allocations per core/operation
295 * @chan - associated channel for this entry
297 struct dma_chan_tbl_ent {
298 struct dma_chan *chan;
302 * channel_table - percpu lookup table for memory-to-memory offload providers
304 static struct dma_chan_tbl_ent __percpu *channel_table[DMA_TX_TYPE_END];
306 static int __init dma_channel_table_init(void)
308 enum dma_transaction_type cap;
311 bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END);
313 /* 'interrupt', 'private', and 'slave' are channel capabilities,
314 * but are not associated with an operation so they do not need
315 * an entry in the channel_table
317 clear_bit(DMA_INTERRUPT, dma_cap_mask_all.bits);
318 clear_bit(DMA_PRIVATE, dma_cap_mask_all.bits);
319 clear_bit(DMA_SLAVE, dma_cap_mask_all.bits);
321 for_each_dma_cap_mask(cap, dma_cap_mask_all) {
322 channel_table[cap] = alloc_percpu(struct dma_chan_tbl_ent);
323 if (!channel_table[cap]) {
330 pr_err("initialization failure\n");
331 for_each_dma_cap_mask(cap, dma_cap_mask_all)
332 if (channel_table[cap])
333 free_percpu(channel_table[cap]);
338 arch_initcall(dma_channel_table_init);
341 * dma_find_channel - find a channel to carry out the operation
342 * @tx_type: transaction type
344 struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
346 return this_cpu_read(channel_table[tx_type]->chan);
348 EXPORT_SYMBOL(dma_find_channel);
351 * net_dma_find_channel - find a channel for net_dma
352 * net_dma has alignment requirements
354 struct dma_chan *net_dma_find_channel(void)
356 struct dma_chan *chan = dma_find_channel(DMA_MEMCPY);
357 if (chan && !is_dma_copy_aligned(chan->device, 1, 1, 1))
362 EXPORT_SYMBOL(net_dma_find_channel);
365 * dma_issue_pending_all - flush all pending operations across all channels
367 void dma_issue_pending_all(void)
369 struct dma_device *device;
370 struct dma_chan *chan;
373 list_for_each_entry_rcu(device, &dma_device_list, global_node) {
374 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
376 list_for_each_entry(chan, &device->channels, device_node)
377 if (chan->client_count)
378 device->device_issue_pending(chan);
382 EXPORT_SYMBOL(dma_issue_pending_all);
385 * dma_chan_is_local - returns true if the channel is in the same numa-node as the cpu
387 static bool dma_chan_is_local(struct dma_chan *chan, int cpu)
389 int node = dev_to_node(chan->device->dev);
390 return node == -1 || cpumask_test_cpu(cpu, cpumask_of_node(node));
394 * min_chan - returns the channel with min count and in the same numa-node as the cpu
395 * @cap: capability to match
396 * @cpu: cpu index which the channel should be close to
398 * If some channels are close to the given cpu, the one with the lowest
399 * reference count is returned. Otherwise, cpu is ignored and only the
400 * reference count is taken into account.
401 * Must be called under dma_list_mutex.
403 static struct dma_chan *min_chan(enum dma_transaction_type cap, int cpu)
405 struct dma_device *device;
406 struct dma_chan *chan;
407 struct dma_chan *min = NULL;
408 struct dma_chan *localmin = NULL;
410 list_for_each_entry(device, &dma_device_list, global_node) {
411 if (!dma_has_cap(cap, device->cap_mask) ||
412 dma_has_cap(DMA_PRIVATE, device->cap_mask))
414 list_for_each_entry(chan, &device->channels, device_node) {
415 if (!chan->client_count)
417 if (!min || chan->table_count < min->table_count)
420 if (dma_chan_is_local(chan, cpu))
422 chan->table_count < localmin->table_count)
427 chan = localmin ? localmin : min;
436 * dma_channel_rebalance - redistribute the available channels
438 * Optimize for cpu isolation (each cpu gets a dedicated channel for an
439 * operation type) in the SMP case, and operation isolation (avoid
440 * multi-tasking channels) in the non-SMP case. Must be called under
443 static void dma_channel_rebalance(void)
445 struct dma_chan *chan;
446 struct dma_device *device;
450 /* undo the last distribution */
451 for_each_dma_cap_mask(cap, dma_cap_mask_all)
452 for_each_possible_cpu(cpu)
453 per_cpu_ptr(channel_table[cap], cpu)->chan = NULL;
455 list_for_each_entry(device, &dma_device_list, global_node) {
456 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
458 list_for_each_entry(chan, &device->channels, device_node)
459 chan->table_count = 0;
462 /* don't populate the channel_table if no clients are available */
463 if (!dmaengine_ref_count)
466 /* redistribute available channels */
467 for_each_dma_cap_mask(cap, dma_cap_mask_all)
468 for_each_online_cpu(cpu) {
469 chan = min_chan(cap, cpu);
470 per_cpu_ptr(channel_table[cap], cpu)->chan = chan;
474 static struct dma_chan *private_candidate(const dma_cap_mask_t *mask,
475 struct dma_device *dev,
476 dma_filter_fn fn, void *fn_param)
478 struct dma_chan *chan;
480 if (!__dma_device_satisfies_mask(dev, mask)) {
481 pr_debug("%s: wrong capabilities\n", __func__);
484 /* devices with multiple channels need special handling as we need to
485 * ensure that all channels are either private or public.
487 if (dev->chancnt > 1 && !dma_has_cap(DMA_PRIVATE, dev->cap_mask))
488 list_for_each_entry(chan, &dev->channels, device_node) {
489 /* some channels are already publicly allocated */
490 if (chan->client_count)
494 list_for_each_entry(chan, &dev->channels, device_node) {
495 if (chan->client_count) {
496 pr_debug("%s: %s busy\n",
497 __func__, dma_chan_name(chan));
500 if (fn && !fn(chan, fn_param)) {
501 pr_debug("%s: %s filter said false\n",
502 __func__, dma_chan_name(chan));
512 * dma_request_channel - try to allocate an exclusive channel
513 * @mask: capabilities that the channel must satisfy
514 * @fn: optional callback to disposition available channels
515 * @fn_param: opaque parameter to pass to dma_filter_fn
517 struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
518 dma_filter_fn fn, void *fn_param)
520 struct dma_device *device, *_d;
521 struct dma_chan *chan = NULL;
525 mutex_lock(&dma_list_mutex);
526 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
527 chan = private_candidate(mask, device, fn, fn_param);
529 /* Found a suitable channel, try to grab, prep, and
530 * return it. We first set DMA_PRIVATE to disable
531 * balance_ref_count as this channel will not be
532 * published in the general-purpose allocator
534 dma_cap_set(DMA_PRIVATE, device->cap_mask);
535 device->privatecnt++;
536 err = dma_chan_get(chan);
538 if (err == -ENODEV) {
539 pr_debug("%s: %s module removed\n",
540 __func__, dma_chan_name(chan));
541 list_del_rcu(&device->global_node);
543 pr_debug("%s: failed to get %s: (%d)\n",
544 __func__, dma_chan_name(chan), err);
547 if (--device->privatecnt == 0)
548 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
552 mutex_unlock(&dma_list_mutex);
554 pr_debug("%s: %s (%s)\n",
556 chan ? "success" : "fail",
557 chan ? dma_chan_name(chan) : NULL);
561 EXPORT_SYMBOL_GPL(__dma_request_channel);
564 * dma_request_slave_channel - try to allocate an exclusive slave channel
565 * @dev: pointer to client device structure
566 * @name: slave channel name
568 struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name)
570 /* If device-tree is present get slave info from here */
572 return of_dma_request_slave_channel(dev->of_node, name);
574 /* If device was enumerated by ACPI get slave info from here */
575 if (ACPI_HANDLE(dev))
576 return acpi_dma_request_slave_chan_by_name(dev, name);
580 EXPORT_SYMBOL_GPL(dma_request_slave_channel);
582 void dma_release_channel(struct dma_chan *chan)
584 mutex_lock(&dma_list_mutex);
585 WARN_ONCE(chan->client_count != 1,
586 "chan reference count %d != 1\n", chan->client_count);
588 /* drop PRIVATE cap enabled by __dma_request_channel() */
589 if (--chan->device->privatecnt == 0)
590 dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
591 mutex_unlock(&dma_list_mutex);
593 EXPORT_SYMBOL_GPL(dma_release_channel);
596 * dmaengine_get - register interest in dma_channels
598 void dmaengine_get(void)
600 struct dma_device *device, *_d;
601 struct dma_chan *chan;
604 mutex_lock(&dma_list_mutex);
605 dmaengine_ref_count++;
607 /* try to grab channels */
608 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
609 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
611 list_for_each_entry(chan, &device->channels, device_node) {
612 err = dma_chan_get(chan);
613 if (err == -ENODEV) {
614 /* module removed before we could use it */
615 list_del_rcu(&device->global_node);
618 pr_debug("%s: failed to get %s: (%d)\n",
619 __func__, dma_chan_name(chan), err);
623 /* if this is the first reference and there were channels
624 * waiting we need to rebalance to get those channels
625 * incorporated into the channel table
627 if (dmaengine_ref_count == 1)
628 dma_channel_rebalance();
629 mutex_unlock(&dma_list_mutex);
631 EXPORT_SYMBOL(dmaengine_get);
634 * dmaengine_put - let dma drivers be removed when ref_count == 0
636 void dmaengine_put(void)
638 struct dma_device *device;
639 struct dma_chan *chan;
641 mutex_lock(&dma_list_mutex);
642 dmaengine_ref_count--;
643 BUG_ON(dmaengine_ref_count < 0);
644 /* drop channel references */
645 list_for_each_entry(device, &dma_device_list, global_node) {
646 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
648 list_for_each_entry(chan, &device->channels, device_node)
651 mutex_unlock(&dma_list_mutex);
653 EXPORT_SYMBOL(dmaengine_put);
655 static bool device_has_all_tx_types(struct dma_device *device)
657 /* A device that satisfies this test has channels that will never cause
658 * an async_tx channel switch event as all possible operation types can
661 #ifdef CONFIG_ASYNC_TX_DMA
662 if (!dma_has_cap(DMA_INTERRUPT, device->cap_mask))
666 #if defined(CONFIG_ASYNC_MEMCPY) || defined(CONFIG_ASYNC_MEMCPY_MODULE)
667 if (!dma_has_cap(DMA_MEMCPY, device->cap_mask))
671 #if defined(CONFIG_ASYNC_XOR) || defined(CONFIG_ASYNC_XOR_MODULE)
672 if (!dma_has_cap(DMA_XOR, device->cap_mask))
675 #ifndef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
676 if (!dma_has_cap(DMA_XOR_VAL, device->cap_mask))
681 #if defined(CONFIG_ASYNC_PQ) || defined(CONFIG_ASYNC_PQ_MODULE)
682 if (!dma_has_cap(DMA_PQ, device->cap_mask))
685 #ifndef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
686 if (!dma_has_cap(DMA_PQ_VAL, device->cap_mask))
694 static int get_dma_id(struct dma_device *device)
698 mutex_lock(&dma_list_mutex);
700 rc = idr_alloc(&dma_idr, NULL, 0, 0, GFP_KERNEL);
704 mutex_unlock(&dma_list_mutex);
705 return rc < 0 ? rc : 0;
709 * dma_async_device_register - registers DMA devices found
710 * @device: &dma_device
712 int dma_async_device_register(struct dma_device *device)
715 struct dma_chan* chan;
721 /* validate device routines */
722 BUG_ON(dma_has_cap(DMA_MEMCPY, device->cap_mask) &&
723 !device->device_prep_dma_memcpy);
724 BUG_ON(dma_has_cap(DMA_XOR, device->cap_mask) &&
725 !device->device_prep_dma_xor);
726 BUG_ON(dma_has_cap(DMA_XOR_VAL, device->cap_mask) &&
727 !device->device_prep_dma_xor_val);
728 BUG_ON(dma_has_cap(DMA_PQ, device->cap_mask) &&
729 !device->device_prep_dma_pq);
730 BUG_ON(dma_has_cap(DMA_PQ_VAL, device->cap_mask) &&
731 !device->device_prep_dma_pq_val);
732 BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) &&
733 !device->device_prep_dma_interrupt);
734 BUG_ON(dma_has_cap(DMA_SG, device->cap_mask) &&
735 !device->device_prep_dma_sg);
736 BUG_ON(dma_has_cap(DMA_CYCLIC, device->cap_mask) &&
737 !device->device_prep_dma_cyclic);
738 BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
739 !device->device_control);
740 BUG_ON(dma_has_cap(DMA_INTERLEAVE, device->cap_mask) &&
741 !device->device_prep_interleaved_dma);
743 BUG_ON(!device->device_alloc_chan_resources);
744 BUG_ON(!device->device_free_chan_resources);
745 BUG_ON(!device->device_tx_status);
746 BUG_ON(!device->device_issue_pending);
747 BUG_ON(!device->dev);
749 /* note: this only matters in the
750 * CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH=n case
752 if (device_has_all_tx_types(device))
753 dma_cap_set(DMA_ASYNC_TX, device->cap_mask);
755 idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL);
758 rc = get_dma_id(device);
764 atomic_set(idr_ref, 0);
766 /* represent channels in sysfs. Probably want devs too */
767 list_for_each_entry(chan, &device->channels, device_node) {
769 chan->local = alloc_percpu(typeof(*chan->local));
770 if (chan->local == NULL)
772 chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
773 if (chan->dev == NULL) {
774 free_percpu(chan->local);
779 chan->chan_id = chancnt++;
780 chan->dev->device.class = &dma_devclass;
781 chan->dev->device.parent = device->dev;
782 chan->dev->chan = chan;
783 chan->dev->idr_ref = idr_ref;
784 chan->dev->dev_id = device->dev_id;
786 dev_set_name(&chan->dev->device, "dma%dchan%d",
787 device->dev_id, chan->chan_id);
789 rc = device_register(&chan->dev->device);
791 free_percpu(chan->local);
797 chan->client_count = 0;
799 device->chancnt = chancnt;
801 mutex_lock(&dma_list_mutex);
802 /* take references on public channels */
803 if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
804 list_for_each_entry(chan, &device->channels, device_node) {
805 /* if clients are already waiting for channels we need
806 * to take references on their behalf
808 if (dma_chan_get(chan) == -ENODEV) {
809 /* note we can only get here for the first
810 * channel as the remaining channels are
811 * guaranteed to get a reference
814 mutex_unlock(&dma_list_mutex);
818 list_add_tail_rcu(&device->global_node, &dma_device_list);
819 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
820 device->privatecnt++; /* Always private */
821 dma_channel_rebalance();
822 mutex_unlock(&dma_list_mutex);
827 /* if we never registered a channel just release the idr */
828 if (atomic_read(idr_ref) == 0) {
829 mutex_lock(&dma_list_mutex);
830 idr_remove(&dma_idr, device->dev_id);
831 mutex_unlock(&dma_list_mutex);
836 list_for_each_entry(chan, &device->channels, device_node) {
837 if (chan->local == NULL)
839 mutex_lock(&dma_list_mutex);
840 chan->dev->chan = NULL;
841 mutex_unlock(&dma_list_mutex);
842 device_unregister(&chan->dev->device);
843 free_percpu(chan->local);
847 EXPORT_SYMBOL(dma_async_device_register);
850 * dma_async_device_unregister - unregister a DMA device
851 * @device: &dma_device
853 * This routine is called by dma driver exit routines, dmaengine holds module
854 * references to prevent it being called while channels are in use.
856 void dma_async_device_unregister(struct dma_device *device)
858 struct dma_chan *chan;
860 mutex_lock(&dma_list_mutex);
861 list_del_rcu(&device->global_node);
862 dma_channel_rebalance();
863 mutex_unlock(&dma_list_mutex);
865 list_for_each_entry(chan, &device->channels, device_node) {
866 WARN_ONCE(chan->client_count,
867 "%s called while %d clients hold a reference\n",
868 __func__, chan->client_count);
869 mutex_lock(&dma_list_mutex);
870 chan->dev->chan = NULL;
871 mutex_unlock(&dma_list_mutex);
872 device_unregister(&chan->dev->device);
873 free_percpu(chan->local);
876 EXPORT_SYMBOL(dma_async_device_unregister);
879 * dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
880 * @chan: DMA channel to offload copy to
881 * @dest: destination address (virtual)
882 * @src: source address (virtual)
885 * Both @dest and @src must be mappable to a bus address according to the
886 * DMA mapping API rules for streaming mappings.
887 * Both @dest and @src must stay memory resident (kernel memory or locked
891 dma_async_memcpy_buf_to_buf(struct dma_chan *chan, void *dest,
892 void *src, size_t len)
894 struct dma_device *dev = chan->device;
895 struct dma_async_tx_descriptor *tx;
896 dma_addr_t dma_dest, dma_src;
900 dma_src = dma_map_single(dev->dev, src, len, DMA_TO_DEVICE);
901 dma_dest = dma_map_single(dev->dev, dest, len, DMA_FROM_DEVICE);
902 flags = DMA_CTRL_ACK |
903 DMA_COMPL_SRC_UNMAP_SINGLE |
904 DMA_COMPL_DEST_UNMAP_SINGLE;
905 tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, flags);
908 dma_unmap_single(dev->dev, dma_src, len, DMA_TO_DEVICE);
909 dma_unmap_single(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
914 cookie = tx->tx_submit(tx);
917 __this_cpu_add(chan->local->bytes_transferred, len);
918 __this_cpu_inc(chan->local->memcpy_count);
923 EXPORT_SYMBOL(dma_async_memcpy_buf_to_buf);
926 * dma_async_memcpy_buf_to_pg - offloaded copy from address to page
927 * @chan: DMA channel to offload copy to
928 * @page: destination page
929 * @offset: offset in page to copy to
930 * @kdata: source address (virtual)
933 * Both @page/@offset and @kdata must be mappable to a bus address according
934 * to the DMA mapping API rules for streaming mappings.
935 * Both @page/@offset and @kdata must stay memory resident (kernel memory or
936 * locked user space pages)
939 dma_async_memcpy_buf_to_pg(struct dma_chan *chan, struct page *page,
940 unsigned int offset, void *kdata, size_t len)
942 struct dma_device *dev = chan->device;
943 struct dma_async_tx_descriptor *tx;
944 dma_addr_t dma_dest, dma_src;
948 dma_src = dma_map_single(dev->dev, kdata, len, DMA_TO_DEVICE);
949 dma_dest = dma_map_page(dev->dev, page, offset, len, DMA_FROM_DEVICE);
950 flags = DMA_CTRL_ACK | DMA_COMPL_SRC_UNMAP_SINGLE;
951 tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, flags);
954 dma_unmap_single(dev->dev, dma_src, len, DMA_TO_DEVICE);
955 dma_unmap_page(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
960 cookie = tx->tx_submit(tx);
963 __this_cpu_add(chan->local->bytes_transferred, len);
964 __this_cpu_inc(chan->local->memcpy_count);
969 EXPORT_SYMBOL(dma_async_memcpy_buf_to_pg);
972 * dma_async_memcpy_pg_to_pg - offloaded copy from page to page
973 * @chan: DMA channel to offload copy to
974 * @dest_pg: destination page
975 * @dest_off: offset in page to copy to
976 * @src_pg: source page
977 * @src_off: offset in page to copy from
980 * Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
981 * address according to the DMA mapping API rules for streaming mappings.
982 * Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
983 * (kernel memory or locked user space pages).
986 dma_async_memcpy_pg_to_pg(struct dma_chan *chan, struct page *dest_pg,
987 unsigned int dest_off, struct page *src_pg, unsigned int src_off,
990 struct dma_device *dev = chan->device;
991 struct dma_async_tx_descriptor *tx;
992 dma_addr_t dma_dest, dma_src;
996 dma_src = dma_map_page(dev->dev, src_pg, src_off, len, DMA_TO_DEVICE);
997 dma_dest = dma_map_page(dev->dev, dest_pg, dest_off, len,
999 flags = DMA_CTRL_ACK;
1000 tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, flags);
1003 dma_unmap_page(dev->dev, dma_src, len, DMA_TO_DEVICE);
1004 dma_unmap_page(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
1008 tx->callback = NULL;
1009 cookie = tx->tx_submit(tx);
1012 __this_cpu_add(chan->local->bytes_transferred, len);
1013 __this_cpu_inc(chan->local->memcpy_count);
1018 EXPORT_SYMBOL(dma_async_memcpy_pg_to_pg);
1020 void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
1021 struct dma_chan *chan)
1024 #ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
1025 spin_lock_init(&tx->lock);
1028 EXPORT_SYMBOL(dma_async_tx_descriptor_init);
1030 /* dma_wait_for_async_tx - spin wait for a transaction to complete
1031 * @tx: in-flight transaction to wait on
1034 dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
1036 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
1041 while (tx->cookie == -EBUSY) {
1042 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
1043 pr_err("%s timeout waiting for descriptor submission\n",
1049 return dma_sync_wait(tx->chan, tx->cookie);
1051 EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
1053 /* dma_run_dependencies - helper routine for dma drivers to process
1054 * (start) dependent operations on their target channel
1055 * @tx: transaction with dependencies
1057 void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
1059 struct dma_async_tx_descriptor *dep = txd_next(tx);
1060 struct dma_async_tx_descriptor *dep_next;
1061 struct dma_chan *chan;
1066 /* we'll submit tx->next now, so clear the link */
1070 /* keep submitting up until a channel switch is detected
1071 * in that case we will be called again as a result of
1072 * processing the interrupt from async_tx_channel_switch
1074 for (; dep; dep = dep_next) {
1076 txd_clear_parent(dep);
1077 dep_next = txd_next(dep);
1078 if (dep_next && dep_next->chan == chan)
1079 txd_clear_next(dep); /* ->next will be submitted */
1081 dep_next = NULL; /* submit current dep and terminate */
1084 dep->tx_submit(dep);
1087 chan->device->device_issue_pending(chan);
1089 EXPORT_SYMBOL_GPL(dma_run_dependencies);
1091 static int __init dma_bus_init(void)
1093 return class_register(&dma_devclass);
1095 arch_initcall(dma_bus_init);