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 * The full GNU General Public License is included in this distribution in the
15 * file called COPYING.
19 * This code implements the DMA subsystem. It provides a HW-neutral interface
20 * for other kernel code to use asynchronous memory copy capabilities,
21 * if present, and allows different HW DMA drivers to register as providing
24 * Due to the fact we are accelerating what is already a relatively fast
25 * operation, the code goes to great lengths to avoid additional overhead,
30 * The subsystem keeps a global list of dma_device structs it is protected by a
31 * mutex, dma_list_mutex.
33 * A subsystem can get access to a channel by calling dmaengine_get() followed
34 * by dma_find_channel(), or if it has need for an exclusive channel it can call
35 * dma_request_channel(). Once a channel is allocated a reference is taken
36 * against its corresponding driver to disable removal.
38 * Each device has a channels list, which runs unlocked but is never modified
39 * once the device is registered, it's just setup by the driver.
41 * See Documentation/dmaengine.txt for more details
44 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
46 #include <linux/dma-mapping.h>
47 #include <linux/init.h>
48 #include <linux/module.h>
50 #include <linux/device.h>
51 #include <linux/dmaengine.h>
52 #include <linux/hardirq.h>
53 #include <linux/spinlock.h>
54 #include <linux/percpu.h>
55 #include <linux/rcupdate.h>
56 #include <linux/mutex.h>
57 #include <linux/jiffies.h>
58 #include <linux/rculist.h>
59 #include <linux/idr.h>
60 #include <linux/slab.h>
61 #include <linux/acpi.h>
62 #include <linux/acpi_dma.h>
63 #include <linux/of_dma.h>
64 #include <linux/mempool.h>
66 static DEFINE_MUTEX(dma_list_mutex);
67 static DEFINE_IDR(dma_idr);
68 static LIST_HEAD(dma_device_list);
69 static long dmaengine_ref_count;
71 /* --- sysfs implementation --- */
74 * dev_to_dma_chan - convert a device pointer to the its sysfs container object
77 * Must be called under dma_list_mutex
79 static struct dma_chan *dev_to_dma_chan(struct device *dev)
81 struct dma_chan_dev *chan_dev;
83 chan_dev = container_of(dev, typeof(*chan_dev), device);
84 return chan_dev->chan;
87 static ssize_t memcpy_count_show(struct device *dev,
88 struct device_attribute *attr, char *buf)
90 struct dma_chan *chan;
91 unsigned long count = 0;
95 mutex_lock(&dma_list_mutex);
96 chan = dev_to_dma_chan(dev);
98 for_each_possible_cpu(i)
99 count += per_cpu_ptr(chan->local, i)->memcpy_count;
100 err = sprintf(buf, "%lu\n", count);
103 mutex_unlock(&dma_list_mutex);
107 static DEVICE_ATTR_RO(memcpy_count);
109 static ssize_t bytes_transferred_show(struct device *dev,
110 struct device_attribute *attr, char *buf)
112 struct dma_chan *chan;
113 unsigned long count = 0;
117 mutex_lock(&dma_list_mutex);
118 chan = dev_to_dma_chan(dev);
120 for_each_possible_cpu(i)
121 count += per_cpu_ptr(chan->local, i)->bytes_transferred;
122 err = sprintf(buf, "%lu\n", count);
125 mutex_unlock(&dma_list_mutex);
129 static DEVICE_ATTR_RO(bytes_transferred);
131 static ssize_t in_use_show(struct device *dev, struct device_attribute *attr,
134 struct dma_chan *chan;
137 mutex_lock(&dma_list_mutex);
138 chan = dev_to_dma_chan(dev);
140 err = sprintf(buf, "%d\n", chan->client_count);
143 mutex_unlock(&dma_list_mutex);
147 static DEVICE_ATTR_RO(in_use);
149 static struct attribute *dma_dev_attrs[] = {
150 &dev_attr_memcpy_count.attr,
151 &dev_attr_bytes_transferred.attr,
152 &dev_attr_in_use.attr,
155 ATTRIBUTE_GROUPS(dma_dev);
157 static void chan_dev_release(struct device *dev)
159 struct dma_chan_dev *chan_dev;
161 chan_dev = container_of(dev, typeof(*chan_dev), device);
162 if (atomic_dec_and_test(chan_dev->idr_ref)) {
163 mutex_lock(&dma_list_mutex);
164 idr_remove(&dma_idr, chan_dev->dev_id);
165 mutex_unlock(&dma_list_mutex);
166 kfree(chan_dev->idr_ref);
171 static struct class dma_devclass = {
173 .dev_groups = dma_dev_groups,
174 .dev_release = chan_dev_release,
177 /* --- client and device registration --- */
179 #define dma_device_satisfies_mask(device, mask) \
180 __dma_device_satisfies_mask((device), &(mask))
182 __dma_device_satisfies_mask(struct dma_device *device,
183 const dma_cap_mask_t *want)
187 bitmap_and(has.bits, want->bits, device->cap_mask.bits,
189 return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END);
192 static struct module *dma_chan_to_owner(struct dma_chan *chan)
194 return chan->device->dev->driver->owner;
198 * balance_ref_count - catch up the channel reference count
199 * @chan - channel to balance ->client_count versus dmaengine_ref_count
201 * balance_ref_count must be called under dma_list_mutex
203 static void balance_ref_count(struct dma_chan *chan)
205 struct module *owner = dma_chan_to_owner(chan);
207 while (chan->client_count < dmaengine_ref_count) {
209 chan->client_count++;
214 * dma_chan_get - try to grab a dma channel's parent driver module
215 * @chan - channel to grab
217 * Must be called under dma_list_mutex
219 static int dma_chan_get(struct dma_chan *chan)
221 struct module *owner = dma_chan_to_owner(chan);
224 /* The channel is already in use, update client count */
225 if (chan->client_count) {
230 if (!try_module_get(owner))
233 /* allocate upon first client reference */
234 if (chan->device->device_alloc_chan_resources) {
235 ret = chan->device->device_alloc_chan_resources(chan);
240 if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
241 balance_ref_count(chan);
244 chan->client_count++;
253 * dma_chan_put - drop a reference to a dma channel's parent driver module
254 * @chan - channel to release
256 * Must be called under dma_list_mutex
258 static void dma_chan_put(struct dma_chan *chan)
260 /* This channel is not in use, bail out */
261 if (!chan->client_count)
264 chan->client_count--;
265 module_put(dma_chan_to_owner(chan));
267 /* This channel is not in use anymore, free it */
268 if (!chan->client_count && chan->device->device_free_chan_resources) {
269 /* Make sure all operations have completed */
270 dmaengine_synchronize(chan);
271 chan->device->device_free_chan_resources(chan);
274 /* If the channel is used via a DMA request router, free the mapping */
275 if (chan->router && chan->router->route_free) {
276 chan->router->route_free(chan->router->dev, chan->route_data);
278 chan->route_data = NULL;
282 enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
284 enum dma_status status;
285 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
287 dma_async_issue_pending(chan);
289 status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
290 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
291 pr_err("%s: timeout!\n", __func__);
294 if (status != DMA_IN_PROGRESS)
301 EXPORT_SYMBOL(dma_sync_wait);
304 * dma_cap_mask_all - enable iteration over all operation types
306 static dma_cap_mask_t dma_cap_mask_all;
309 * dma_chan_tbl_ent - tracks channel allocations per core/operation
310 * @chan - associated channel for this entry
312 struct dma_chan_tbl_ent {
313 struct dma_chan *chan;
317 * channel_table - percpu lookup table for memory-to-memory offload providers
319 static struct dma_chan_tbl_ent __percpu *channel_table[DMA_TX_TYPE_END];
321 static int __init dma_channel_table_init(void)
323 enum dma_transaction_type cap;
326 bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END);
328 /* 'interrupt', 'private', and 'slave' are channel capabilities,
329 * but are not associated with an operation so they do not need
330 * an entry in the channel_table
332 clear_bit(DMA_INTERRUPT, dma_cap_mask_all.bits);
333 clear_bit(DMA_PRIVATE, dma_cap_mask_all.bits);
334 clear_bit(DMA_SLAVE, dma_cap_mask_all.bits);
336 for_each_dma_cap_mask(cap, dma_cap_mask_all) {
337 channel_table[cap] = alloc_percpu(struct dma_chan_tbl_ent);
338 if (!channel_table[cap]) {
345 pr_err("initialization failure\n");
346 for_each_dma_cap_mask(cap, dma_cap_mask_all)
347 free_percpu(channel_table[cap]);
352 arch_initcall(dma_channel_table_init);
355 * dma_find_channel - find a channel to carry out the operation
356 * @tx_type: transaction type
358 struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
360 return this_cpu_read(channel_table[tx_type]->chan);
362 EXPORT_SYMBOL(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 int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps)
476 struct dma_device *device;
481 device = chan->device;
483 /* check if the channel supports slave transactions */
484 if (!test_bit(DMA_SLAVE, device->cap_mask.bits))
488 * Check whether it reports it uses the generic slave
489 * capabilities, if not, that means it doesn't support any
490 * kind of slave capabilities reporting.
492 if (!device->directions)
495 caps->src_addr_widths = device->src_addr_widths;
496 caps->dst_addr_widths = device->dst_addr_widths;
497 caps->directions = device->directions;
498 caps->max_burst = device->max_burst;
499 caps->residue_granularity = device->residue_granularity;
502 * Some devices implement only pause (e.g. to get residuum) but no
503 * resume. However cmd_pause is advertised as pause AND resume.
505 caps->cmd_pause = !!(device->device_pause && device->device_resume);
506 caps->cmd_terminate = !!device->device_terminate_all;
510 EXPORT_SYMBOL_GPL(dma_get_slave_caps);
512 static struct dma_chan *private_candidate(const dma_cap_mask_t *mask,
513 struct dma_device *dev,
514 dma_filter_fn fn, void *fn_param)
516 struct dma_chan *chan;
518 if (mask && !__dma_device_satisfies_mask(dev, mask)) {
519 pr_debug("%s: wrong capabilities\n", __func__);
522 /* devices with multiple channels need special handling as we need to
523 * ensure that all channels are either private or public.
525 if (dev->chancnt > 1 && !dma_has_cap(DMA_PRIVATE, dev->cap_mask))
526 list_for_each_entry(chan, &dev->channels, device_node) {
527 /* some channels are already publicly allocated */
528 if (chan->client_count)
532 list_for_each_entry(chan, &dev->channels, device_node) {
533 if (chan->client_count) {
534 pr_debug("%s: %s busy\n",
535 __func__, dma_chan_name(chan));
538 if (fn && !fn(chan, fn_param)) {
539 pr_debug("%s: %s filter said false\n",
540 __func__, dma_chan_name(chan));
550 * dma_get_slave_channel - try to get specific channel exclusively
551 * @chan: target channel
553 struct dma_chan *dma_get_slave_channel(struct dma_chan *chan)
557 /* lock against __dma_request_channel */
558 mutex_lock(&dma_list_mutex);
560 if (chan->client_count == 0) {
561 struct dma_device *device = chan->device;
563 dma_cap_set(DMA_PRIVATE, device->cap_mask);
564 device->privatecnt++;
565 err = dma_chan_get(chan);
567 pr_debug("%s: failed to get %s: (%d)\n",
568 __func__, dma_chan_name(chan), err);
570 if (--device->privatecnt == 0)
571 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
576 mutex_unlock(&dma_list_mutex);
581 EXPORT_SYMBOL_GPL(dma_get_slave_channel);
583 struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)
586 struct dma_chan *chan;
590 dma_cap_set(DMA_SLAVE, mask);
592 /* lock against __dma_request_channel */
593 mutex_lock(&dma_list_mutex);
595 chan = private_candidate(&mask, device, NULL, NULL);
597 dma_cap_set(DMA_PRIVATE, device->cap_mask);
598 device->privatecnt++;
599 err = dma_chan_get(chan);
601 pr_debug("%s: failed to get %s: (%d)\n",
602 __func__, dma_chan_name(chan), err);
604 if (--device->privatecnt == 0)
605 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
609 mutex_unlock(&dma_list_mutex);
613 EXPORT_SYMBOL_GPL(dma_get_any_slave_channel);
616 * __dma_request_channel - try to allocate an exclusive channel
617 * @mask: capabilities that the channel must satisfy
618 * @fn: optional callback to disposition available channels
619 * @fn_param: opaque parameter to pass to dma_filter_fn
621 * Returns pointer to appropriate DMA channel on success or NULL.
623 struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
624 dma_filter_fn fn, void *fn_param)
626 struct dma_device *device, *_d;
627 struct dma_chan *chan = NULL;
631 mutex_lock(&dma_list_mutex);
632 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
633 chan = private_candidate(mask, device, fn, fn_param);
635 /* Found a suitable channel, try to grab, prep, and
636 * return it. We first set DMA_PRIVATE to disable
637 * balance_ref_count as this channel will not be
638 * published in the general-purpose allocator
640 dma_cap_set(DMA_PRIVATE, device->cap_mask);
641 device->privatecnt++;
642 err = dma_chan_get(chan);
644 if (err == -ENODEV) {
645 pr_debug("%s: %s module removed\n",
646 __func__, dma_chan_name(chan));
647 list_del_rcu(&device->global_node);
649 pr_debug("%s: failed to get %s: (%d)\n",
650 __func__, dma_chan_name(chan), err);
653 if (--device->privatecnt == 0)
654 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
658 mutex_unlock(&dma_list_mutex);
660 pr_debug("%s: %s (%s)\n",
662 chan ? "success" : "fail",
663 chan ? dma_chan_name(chan) : NULL);
667 EXPORT_SYMBOL_GPL(__dma_request_channel);
670 * dma_request_slave_channel_reason - try to allocate an exclusive slave channel
671 * @dev: pointer to client device structure
672 * @name: slave channel name
674 * Returns pointer to appropriate DMA channel on success or an error pointer.
676 struct dma_chan *dma_request_slave_channel_reason(struct device *dev,
679 /* If device-tree is present get slave info from here */
681 return of_dma_request_slave_channel(dev->of_node, name);
683 /* If device was enumerated by ACPI get slave info from here */
684 if (ACPI_HANDLE(dev))
685 return acpi_dma_request_slave_chan_by_name(dev, name);
687 return ERR_PTR(-ENODEV);
689 EXPORT_SYMBOL_GPL(dma_request_slave_channel_reason);
692 * dma_request_slave_channel - try to allocate an exclusive slave channel
693 * @dev: pointer to client device structure
694 * @name: slave channel name
696 * Returns pointer to appropriate DMA channel on success or NULL.
698 struct dma_chan *dma_request_slave_channel(struct device *dev,
701 struct dma_chan *ch = dma_request_slave_channel_reason(dev, name);
705 dma_cap_set(DMA_PRIVATE, ch->device->cap_mask);
706 ch->device->privatecnt++;
710 EXPORT_SYMBOL_GPL(dma_request_slave_channel);
712 void dma_release_channel(struct dma_chan *chan)
714 mutex_lock(&dma_list_mutex);
715 WARN_ONCE(chan->client_count != 1,
716 "chan reference count %d != 1\n", chan->client_count);
718 /* drop PRIVATE cap enabled by __dma_request_channel() */
719 if (--chan->device->privatecnt == 0)
720 dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
721 mutex_unlock(&dma_list_mutex);
723 EXPORT_SYMBOL_GPL(dma_release_channel);
726 * dmaengine_get - register interest in dma_channels
728 void dmaengine_get(void)
730 struct dma_device *device, *_d;
731 struct dma_chan *chan;
734 mutex_lock(&dma_list_mutex);
735 dmaengine_ref_count++;
737 /* try to grab channels */
738 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
739 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
741 list_for_each_entry(chan, &device->channels, device_node) {
742 err = dma_chan_get(chan);
743 if (err == -ENODEV) {
744 /* module removed before we could use it */
745 list_del_rcu(&device->global_node);
748 pr_debug("%s: failed to get %s: (%d)\n",
749 __func__, dma_chan_name(chan), err);
753 /* if this is the first reference and there were channels
754 * waiting we need to rebalance to get those channels
755 * incorporated into the channel table
757 if (dmaengine_ref_count == 1)
758 dma_channel_rebalance();
759 mutex_unlock(&dma_list_mutex);
761 EXPORT_SYMBOL(dmaengine_get);
764 * dmaengine_put - let dma drivers be removed when ref_count == 0
766 void dmaengine_put(void)
768 struct dma_device *device;
769 struct dma_chan *chan;
771 mutex_lock(&dma_list_mutex);
772 dmaengine_ref_count--;
773 BUG_ON(dmaengine_ref_count < 0);
774 /* drop channel references */
775 list_for_each_entry(device, &dma_device_list, global_node) {
776 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
778 list_for_each_entry(chan, &device->channels, device_node)
781 mutex_unlock(&dma_list_mutex);
783 EXPORT_SYMBOL(dmaengine_put);
785 static bool device_has_all_tx_types(struct dma_device *device)
787 /* A device that satisfies this test has channels that will never cause
788 * an async_tx channel switch event as all possible operation types can
791 #ifdef CONFIG_ASYNC_TX_DMA
792 if (!dma_has_cap(DMA_INTERRUPT, device->cap_mask))
796 #if defined(CONFIG_ASYNC_MEMCPY) || defined(CONFIG_ASYNC_MEMCPY_MODULE)
797 if (!dma_has_cap(DMA_MEMCPY, device->cap_mask))
801 #if defined(CONFIG_ASYNC_XOR) || defined(CONFIG_ASYNC_XOR_MODULE)
802 if (!dma_has_cap(DMA_XOR, device->cap_mask))
805 #ifndef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
806 if (!dma_has_cap(DMA_XOR_VAL, device->cap_mask))
811 #if defined(CONFIG_ASYNC_PQ) || defined(CONFIG_ASYNC_PQ_MODULE)
812 if (!dma_has_cap(DMA_PQ, device->cap_mask))
815 #ifndef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
816 if (!dma_has_cap(DMA_PQ_VAL, device->cap_mask))
824 static int get_dma_id(struct dma_device *device)
828 mutex_lock(&dma_list_mutex);
830 rc = idr_alloc(&dma_idr, NULL, 0, 0, GFP_KERNEL);
834 mutex_unlock(&dma_list_mutex);
835 return rc < 0 ? rc : 0;
839 * dma_async_device_register - registers DMA devices found
840 * @device: &dma_device
842 int dma_async_device_register(struct dma_device *device)
845 struct dma_chan* chan;
851 /* validate device routines */
852 BUG_ON(dma_has_cap(DMA_MEMCPY, device->cap_mask) &&
853 !device->device_prep_dma_memcpy);
854 BUG_ON(dma_has_cap(DMA_XOR, device->cap_mask) &&
855 !device->device_prep_dma_xor);
856 BUG_ON(dma_has_cap(DMA_XOR_VAL, device->cap_mask) &&
857 !device->device_prep_dma_xor_val);
858 BUG_ON(dma_has_cap(DMA_PQ, device->cap_mask) &&
859 !device->device_prep_dma_pq);
860 BUG_ON(dma_has_cap(DMA_PQ_VAL, device->cap_mask) &&
861 !device->device_prep_dma_pq_val);
862 BUG_ON(dma_has_cap(DMA_MEMSET, device->cap_mask) &&
863 !device->device_prep_dma_memset);
864 BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) &&
865 !device->device_prep_dma_interrupt);
866 BUG_ON(dma_has_cap(DMA_SG, device->cap_mask) &&
867 !device->device_prep_dma_sg);
868 BUG_ON(dma_has_cap(DMA_CYCLIC, device->cap_mask) &&
869 !device->device_prep_dma_cyclic);
870 BUG_ON(dma_has_cap(DMA_INTERLEAVE, device->cap_mask) &&
871 !device->device_prep_interleaved_dma);
873 BUG_ON(!device->device_tx_status);
874 BUG_ON(!device->device_issue_pending);
875 BUG_ON(!device->dev);
877 /* note: this only matters in the
878 * CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH=n case
880 if (device_has_all_tx_types(device))
881 dma_cap_set(DMA_ASYNC_TX, device->cap_mask);
883 idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL);
886 rc = get_dma_id(device);
892 atomic_set(idr_ref, 0);
894 /* represent channels in sysfs. Probably want devs too */
895 list_for_each_entry(chan, &device->channels, device_node) {
897 chan->local = alloc_percpu(typeof(*chan->local));
898 if (chan->local == NULL)
900 chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
901 if (chan->dev == NULL) {
902 free_percpu(chan->local);
907 chan->chan_id = chancnt++;
908 chan->dev->device.class = &dma_devclass;
909 chan->dev->device.parent = device->dev;
910 chan->dev->chan = chan;
911 chan->dev->idr_ref = idr_ref;
912 chan->dev->dev_id = device->dev_id;
914 dev_set_name(&chan->dev->device, "dma%dchan%d",
915 device->dev_id, chan->chan_id);
917 rc = device_register(&chan->dev->device);
919 free_percpu(chan->local);
925 chan->client_count = 0;
927 device->chancnt = chancnt;
929 mutex_lock(&dma_list_mutex);
930 /* take references on public channels */
931 if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
932 list_for_each_entry(chan, &device->channels, device_node) {
933 /* if clients are already waiting for channels we need
934 * to take references on their behalf
936 if (dma_chan_get(chan) == -ENODEV) {
937 /* note we can only get here for the first
938 * channel as the remaining channels are
939 * guaranteed to get a reference
942 mutex_unlock(&dma_list_mutex);
946 list_add_tail_rcu(&device->global_node, &dma_device_list);
947 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
948 device->privatecnt++; /* Always private */
949 dma_channel_rebalance();
950 mutex_unlock(&dma_list_mutex);
955 /* if we never registered a channel just release the idr */
956 if (atomic_read(idr_ref) == 0) {
957 mutex_lock(&dma_list_mutex);
958 idr_remove(&dma_idr, device->dev_id);
959 mutex_unlock(&dma_list_mutex);
964 list_for_each_entry(chan, &device->channels, device_node) {
965 if (chan->local == NULL)
967 mutex_lock(&dma_list_mutex);
968 chan->dev->chan = NULL;
969 mutex_unlock(&dma_list_mutex);
970 device_unregister(&chan->dev->device);
971 free_percpu(chan->local);
975 EXPORT_SYMBOL(dma_async_device_register);
978 * dma_async_device_unregister - unregister a DMA device
979 * @device: &dma_device
981 * This routine is called by dma driver exit routines, dmaengine holds module
982 * references to prevent it being called while channels are in use.
984 void dma_async_device_unregister(struct dma_device *device)
986 struct dma_chan *chan;
988 mutex_lock(&dma_list_mutex);
989 list_del_rcu(&device->global_node);
990 dma_channel_rebalance();
991 mutex_unlock(&dma_list_mutex);
993 list_for_each_entry(chan, &device->channels, device_node) {
994 WARN_ONCE(chan->client_count,
995 "%s called while %d clients hold a reference\n",
996 __func__, chan->client_count);
997 mutex_lock(&dma_list_mutex);
998 chan->dev->chan = NULL;
999 mutex_unlock(&dma_list_mutex);
1000 device_unregister(&chan->dev->device);
1001 free_percpu(chan->local);
1004 EXPORT_SYMBOL(dma_async_device_unregister);
1006 struct dmaengine_unmap_pool {
1007 struct kmem_cache *cache;
1013 #define __UNMAP_POOL(x) { .size = x, .name = "dmaengine-unmap-" __stringify(x) }
1014 static struct dmaengine_unmap_pool unmap_pool[] = {
1016 #if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
1023 static struct dmaengine_unmap_pool *__get_unmap_pool(int nr)
1025 int order = get_count_order(nr);
1029 return &unmap_pool[0];
1031 return &unmap_pool[1];
1033 return &unmap_pool[2];
1035 return &unmap_pool[3];
1042 static void dmaengine_unmap(struct kref *kref)
1044 struct dmaengine_unmap_data *unmap = container_of(kref, typeof(*unmap), kref);
1045 struct device *dev = unmap->dev;
1048 cnt = unmap->to_cnt;
1049 for (i = 0; i < cnt; i++)
1050 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1052 cnt += unmap->from_cnt;
1053 for (; i < cnt; i++)
1054 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1056 cnt += unmap->bidi_cnt;
1057 for (; i < cnt; i++) {
1058 if (unmap->addr[i] == 0)
1060 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1063 cnt = unmap->map_cnt;
1064 mempool_free(unmap, __get_unmap_pool(cnt)->pool);
1067 void dmaengine_unmap_put(struct dmaengine_unmap_data *unmap)
1070 kref_put(&unmap->kref, dmaengine_unmap);
1072 EXPORT_SYMBOL_GPL(dmaengine_unmap_put);
1074 static void dmaengine_destroy_unmap_pool(void)
1078 for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
1079 struct dmaengine_unmap_pool *p = &unmap_pool[i];
1081 mempool_destroy(p->pool);
1083 kmem_cache_destroy(p->cache);
1088 static int __init dmaengine_init_unmap_pool(void)
1092 for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
1093 struct dmaengine_unmap_pool *p = &unmap_pool[i];
1096 size = sizeof(struct dmaengine_unmap_data) +
1097 sizeof(dma_addr_t) * p->size;
1099 p->cache = kmem_cache_create(p->name, size, 0,
1100 SLAB_HWCACHE_ALIGN, NULL);
1103 p->pool = mempool_create_slab_pool(1, p->cache);
1108 if (i == ARRAY_SIZE(unmap_pool))
1111 dmaengine_destroy_unmap_pool();
1115 struct dmaengine_unmap_data *
1116 dmaengine_get_unmap_data(struct device *dev, int nr, gfp_t flags)
1118 struct dmaengine_unmap_data *unmap;
1120 unmap = mempool_alloc(__get_unmap_pool(nr)->pool, flags);
1124 memset(unmap, 0, sizeof(*unmap));
1125 kref_init(&unmap->kref);
1127 unmap->map_cnt = nr;
1131 EXPORT_SYMBOL(dmaengine_get_unmap_data);
1133 void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
1134 struct dma_chan *chan)
1137 #ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
1138 spin_lock_init(&tx->lock);
1141 EXPORT_SYMBOL(dma_async_tx_descriptor_init);
1143 /* dma_wait_for_async_tx - spin wait for a transaction to complete
1144 * @tx: in-flight transaction to wait on
1147 dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
1149 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
1152 return DMA_COMPLETE;
1154 while (tx->cookie == -EBUSY) {
1155 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
1156 pr_err("%s timeout waiting for descriptor submission\n",
1162 return dma_sync_wait(tx->chan, tx->cookie);
1164 EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
1166 /* dma_run_dependencies - helper routine for dma drivers to process
1167 * (start) dependent operations on their target channel
1168 * @tx: transaction with dependencies
1170 void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
1172 struct dma_async_tx_descriptor *dep = txd_next(tx);
1173 struct dma_async_tx_descriptor *dep_next;
1174 struct dma_chan *chan;
1179 /* we'll submit tx->next now, so clear the link */
1183 /* keep submitting up until a channel switch is detected
1184 * in that case we will be called again as a result of
1185 * processing the interrupt from async_tx_channel_switch
1187 for (; dep; dep = dep_next) {
1189 txd_clear_parent(dep);
1190 dep_next = txd_next(dep);
1191 if (dep_next && dep_next->chan == chan)
1192 txd_clear_next(dep); /* ->next will be submitted */
1194 dep_next = NULL; /* submit current dep and terminate */
1197 dep->tx_submit(dep);
1200 chan->device->device_issue_pending(chan);
1202 EXPORT_SYMBOL_GPL(dma_run_dependencies);
1204 static int __init dma_bus_init(void)
1206 int err = dmaengine_init_unmap_pool();
1210 return class_register(&dma_devclass);
1212 arch_initcall(dma_bus_init);