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 chan->device->device_free_chan_resources(chan);
271 /* If the channel is used via a DMA request router, free the mapping */
272 if (chan->router && chan->router->route_free) {
273 chan->router->route_free(chan->router->dev, chan->route_data);
275 chan->route_data = NULL;
279 enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
281 enum dma_status status;
282 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
284 dma_async_issue_pending(chan);
286 status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
287 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
288 pr_err("%s: timeout!\n", __func__);
291 if (status != DMA_IN_PROGRESS)
298 EXPORT_SYMBOL(dma_sync_wait);
301 * dma_cap_mask_all - enable iteration over all operation types
303 static dma_cap_mask_t dma_cap_mask_all;
306 * dma_chan_tbl_ent - tracks channel allocations per core/operation
307 * @chan - associated channel for this entry
309 struct dma_chan_tbl_ent {
310 struct dma_chan *chan;
314 * channel_table - percpu lookup table for memory-to-memory offload providers
316 static struct dma_chan_tbl_ent __percpu *channel_table[DMA_TX_TYPE_END];
318 static int __init dma_channel_table_init(void)
320 enum dma_transaction_type cap;
323 bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END);
325 /* 'interrupt', 'private', and 'slave' are channel capabilities,
326 * but are not associated with an operation so they do not need
327 * an entry in the channel_table
329 clear_bit(DMA_INTERRUPT, dma_cap_mask_all.bits);
330 clear_bit(DMA_PRIVATE, dma_cap_mask_all.bits);
331 clear_bit(DMA_SLAVE, dma_cap_mask_all.bits);
333 for_each_dma_cap_mask(cap, dma_cap_mask_all) {
334 channel_table[cap] = alloc_percpu(struct dma_chan_tbl_ent);
335 if (!channel_table[cap]) {
342 pr_err("initialization failure\n");
343 for_each_dma_cap_mask(cap, dma_cap_mask_all)
344 free_percpu(channel_table[cap]);
349 arch_initcall(dma_channel_table_init);
352 * dma_find_channel - find a channel to carry out the operation
353 * @tx_type: transaction type
355 struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
357 return this_cpu_read(channel_table[tx_type]->chan);
359 EXPORT_SYMBOL(dma_find_channel);
362 * dma_issue_pending_all - flush all pending operations across all channels
364 void dma_issue_pending_all(void)
366 struct dma_device *device;
367 struct dma_chan *chan;
370 list_for_each_entry_rcu(device, &dma_device_list, global_node) {
371 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
373 list_for_each_entry(chan, &device->channels, device_node)
374 if (chan->client_count)
375 device->device_issue_pending(chan);
379 EXPORT_SYMBOL(dma_issue_pending_all);
382 * dma_chan_is_local - returns true if the channel is in the same numa-node as the cpu
384 static bool dma_chan_is_local(struct dma_chan *chan, int cpu)
386 int node = dev_to_node(chan->device->dev);
387 return node == -1 || cpumask_test_cpu(cpu, cpumask_of_node(node));
391 * min_chan - returns the channel with min count and in the same numa-node as the cpu
392 * @cap: capability to match
393 * @cpu: cpu index which the channel should be close to
395 * If some channels are close to the given cpu, the one with the lowest
396 * reference count is returned. Otherwise, cpu is ignored and only the
397 * reference count is taken into account.
398 * Must be called under dma_list_mutex.
400 static struct dma_chan *min_chan(enum dma_transaction_type cap, int cpu)
402 struct dma_device *device;
403 struct dma_chan *chan;
404 struct dma_chan *min = NULL;
405 struct dma_chan *localmin = NULL;
407 list_for_each_entry(device, &dma_device_list, global_node) {
408 if (!dma_has_cap(cap, device->cap_mask) ||
409 dma_has_cap(DMA_PRIVATE, device->cap_mask))
411 list_for_each_entry(chan, &device->channels, device_node) {
412 if (!chan->client_count)
414 if (!min || chan->table_count < min->table_count)
417 if (dma_chan_is_local(chan, cpu))
419 chan->table_count < localmin->table_count)
424 chan = localmin ? localmin : min;
433 * dma_channel_rebalance - redistribute the available channels
435 * Optimize for cpu isolation (each cpu gets a dedicated channel for an
436 * operation type) in the SMP case, and operation isolation (avoid
437 * multi-tasking channels) in the non-SMP case. Must be called under
440 static void dma_channel_rebalance(void)
442 struct dma_chan *chan;
443 struct dma_device *device;
447 /* undo the last distribution */
448 for_each_dma_cap_mask(cap, dma_cap_mask_all)
449 for_each_possible_cpu(cpu)
450 per_cpu_ptr(channel_table[cap], cpu)->chan = NULL;
452 list_for_each_entry(device, &dma_device_list, global_node) {
453 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
455 list_for_each_entry(chan, &device->channels, device_node)
456 chan->table_count = 0;
459 /* don't populate the channel_table if no clients are available */
460 if (!dmaengine_ref_count)
463 /* redistribute available channels */
464 for_each_dma_cap_mask(cap, dma_cap_mask_all)
465 for_each_online_cpu(cpu) {
466 chan = min_chan(cap, cpu);
467 per_cpu_ptr(channel_table[cap], cpu)->chan = chan;
471 int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps)
473 struct dma_device *device;
478 device = chan->device;
480 /* check if the channel supports slave transactions */
481 if (!test_bit(DMA_SLAVE, device->cap_mask.bits))
485 * Check whether it reports it uses the generic slave
486 * capabilities, if not, that means it doesn't support any
487 * kind of slave capabilities reporting.
489 if (!device->directions)
492 caps->src_addr_widths = device->src_addr_widths;
493 caps->dst_addr_widths = device->dst_addr_widths;
494 caps->directions = device->directions;
495 caps->max_burst = device->max_burst;
496 caps->residue_granularity = device->residue_granularity;
499 * Some devices implement only pause (e.g. to get residuum) but no
500 * resume. However cmd_pause is advertised as pause AND resume.
502 caps->cmd_pause = !!(device->device_pause && device->device_resume);
503 caps->cmd_terminate = !!device->device_terminate_all;
507 EXPORT_SYMBOL_GPL(dma_get_slave_caps);
509 static struct dma_chan *private_candidate(const dma_cap_mask_t *mask,
510 struct dma_device *dev,
511 dma_filter_fn fn, void *fn_param)
513 struct dma_chan *chan;
515 if (!__dma_device_satisfies_mask(dev, mask)) {
516 pr_debug("%s: wrong capabilities\n", __func__);
519 /* devices with multiple channels need special handling as we need to
520 * ensure that all channels are either private or public.
522 if (dev->chancnt > 1 && !dma_has_cap(DMA_PRIVATE, dev->cap_mask))
523 list_for_each_entry(chan, &dev->channels, device_node) {
524 /* some channels are already publicly allocated */
525 if (chan->client_count)
529 list_for_each_entry(chan, &dev->channels, device_node) {
530 if (chan->client_count) {
531 pr_debug("%s: %s busy\n",
532 __func__, dma_chan_name(chan));
535 if (fn && !fn(chan, fn_param)) {
536 pr_debug("%s: %s filter said false\n",
537 __func__, dma_chan_name(chan));
547 * dma_get_slave_channel - try to get specific channel exclusively
548 * @chan: target channel
550 struct dma_chan *dma_get_slave_channel(struct dma_chan *chan)
554 /* lock against __dma_request_channel */
555 mutex_lock(&dma_list_mutex);
557 if (chan->client_count == 0) {
558 struct dma_device *device = chan->device;
560 dma_cap_set(DMA_PRIVATE, device->cap_mask);
561 device->privatecnt++;
562 err = dma_chan_get(chan);
564 pr_debug("%s: failed to get %s: (%d)\n",
565 __func__, dma_chan_name(chan), err);
567 if (--device->privatecnt == 0)
568 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
573 mutex_unlock(&dma_list_mutex);
578 EXPORT_SYMBOL_GPL(dma_get_slave_channel);
580 struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)
583 struct dma_chan *chan;
587 dma_cap_set(DMA_SLAVE, mask);
589 /* lock against __dma_request_channel */
590 mutex_lock(&dma_list_mutex);
592 chan = private_candidate(&mask, device, NULL, NULL);
594 dma_cap_set(DMA_PRIVATE, device->cap_mask);
595 device->privatecnt++;
596 err = dma_chan_get(chan);
598 pr_debug("%s: failed to get %s: (%d)\n",
599 __func__, dma_chan_name(chan), err);
601 if (--device->privatecnt == 0)
602 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
606 mutex_unlock(&dma_list_mutex);
610 EXPORT_SYMBOL_GPL(dma_get_any_slave_channel);
613 * __dma_request_channel - try to allocate an exclusive channel
614 * @mask: capabilities that the channel must satisfy
615 * @fn: optional callback to disposition available channels
616 * @fn_param: opaque parameter to pass to dma_filter_fn
618 * Returns pointer to appropriate DMA channel on success or NULL.
620 struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
621 dma_filter_fn fn, void *fn_param)
623 struct dma_device *device, *_d;
624 struct dma_chan *chan = NULL;
628 mutex_lock(&dma_list_mutex);
629 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
630 chan = private_candidate(mask, device, fn, fn_param);
632 /* Found a suitable channel, try to grab, prep, and
633 * return it. We first set DMA_PRIVATE to disable
634 * balance_ref_count as this channel will not be
635 * published in the general-purpose allocator
637 dma_cap_set(DMA_PRIVATE, device->cap_mask);
638 device->privatecnt++;
639 err = dma_chan_get(chan);
641 if (err == -ENODEV) {
642 pr_debug("%s: %s module removed\n",
643 __func__, dma_chan_name(chan));
644 list_del_rcu(&device->global_node);
646 pr_debug("%s: failed to get %s: (%d)\n",
647 __func__, dma_chan_name(chan), err);
650 if (--device->privatecnt == 0)
651 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
655 mutex_unlock(&dma_list_mutex);
657 pr_debug("%s: %s (%s)\n",
659 chan ? "success" : "fail",
660 chan ? dma_chan_name(chan) : NULL);
664 EXPORT_SYMBOL_GPL(__dma_request_channel);
667 * dma_request_slave_channel_reason - try to allocate an exclusive slave channel
668 * @dev: pointer to client device structure
669 * @name: slave channel name
671 * Returns pointer to appropriate DMA channel on success or an error pointer.
673 struct dma_chan *dma_request_slave_channel_reason(struct device *dev,
676 /* If device-tree is present get slave info from here */
678 return of_dma_request_slave_channel(dev->of_node, name);
680 /* If device was enumerated by ACPI get slave info from here */
681 if (ACPI_HANDLE(dev))
682 return acpi_dma_request_slave_chan_by_name(dev, name);
684 return ERR_PTR(-ENODEV);
686 EXPORT_SYMBOL_GPL(dma_request_slave_channel_reason);
689 * dma_request_slave_channel - try to allocate an exclusive slave channel
690 * @dev: pointer to client device structure
691 * @name: slave channel name
693 * Returns pointer to appropriate DMA channel on success or NULL.
695 struct dma_chan *dma_request_slave_channel(struct device *dev,
698 struct dma_chan *ch = dma_request_slave_channel_reason(dev, name);
702 dma_cap_set(DMA_PRIVATE, ch->device->cap_mask);
703 ch->device->privatecnt++;
707 EXPORT_SYMBOL_GPL(dma_request_slave_channel);
709 void dma_release_channel(struct dma_chan *chan)
711 mutex_lock(&dma_list_mutex);
712 WARN_ONCE(chan->client_count != 1,
713 "chan reference count %d != 1\n", chan->client_count);
715 /* drop PRIVATE cap enabled by __dma_request_channel() */
716 if (--chan->device->privatecnt == 0)
717 dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
718 mutex_unlock(&dma_list_mutex);
720 EXPORT_SYMBOL_GPL(dma_release_channel);
723 * dmaengine_get - register interest in dma_channels
725 void dmaengine_get(void)
727 struct dma_device *device, *_d;
728 struct dma_chan *chan;
731 mutex_lock(&dma_list_mutex);
732 dmaengine_ref_count++;
734 /* try to grab channels */
735 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
736 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
738 list_for_each_entry(chan, &device->channels, device_node) {
739 err = dma_chan_get(chan);
740 if (err == -ENODEV) {
741 /* module removed before we could use it */
742 list_del_rcu(&device->global_node);
745 pr_debug("%s: failed to get %s: (%d)\n",
746 __func__, dma_chan_name(chan), err);
750 /* if this is the first reference and there were channels
751 * waiting we need to rebalance to get those channels
752 * incorporated into the channel table
754 if (dmaengine_ref_count == 1)
755 dma_channel_rebalance();
756 mutex_unlock(&dma_list_mutex);
758 EXPORT_SYMBOL(dmaengine_get);
761 * dmaengine_put - let dma drivers be removed when ref_count == 0
763 void dmaengine_put(void)
765 struct dma_device *device;
766 struct dma_chan *chan;
768 mutex_lock(&dma_list_mutex);
769 dmaengine_ref_count--;
770 BUG_ON(dmaengine_ref_count < 0);
771 /* drop channel references */
772 list_for_each_entry(device, &dma_device_list, global_node) {
773 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
775 list_for_each_entry(chan, &device->channels, device_node)
778 mutex_unlock(&dma_list_mutex);
780 EXPORT_SYMBOL(dmaengine_put);
782 static bool device_has_all_tx_types(struct dma_device *device)
784 /* A device that satisfies this test has channels that will never cause
785 * an async_tx channel switch event as all possible operation types can
788 #ifdef CONFIG_ASYNC_TX_DMA
789 if (!dma_has_cap(DMA_INTERRUPT, device->cap_mask))
793 #if defined(CONFIG_ASYNC_MEMCPY) || defined(CONFIG_ASYNC_MEMCPY_MODULE)
794 if (!dma_has_cap(DMA_MEMCPY, device->cap_mask))
798 #if defined(CONFIG_ASYNC_XOR) || defined(CONFIG_ASYNC_XOR_MODULE)
799 if (!dma_has_cap(DMA_XOR, device->cap_mask))
802 #ifndef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
803 if (!dma_has_cap(DMA_XOR_VAL, device->cap_mask))
808 #if defined(CONFIG_ASYNC_PQ) || defined(CONFIG_ASYNC_PQ_MODULE)
809 if (!dma_has_cap(DMA_PQ, device->cap_mask))
812 #ifndef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
813 if (!dma_has_cap(DMA_PQ_VAL, device->cap_mask))
821 static int get_dma_id(struct dma_device *device)
825 mutex_lock(&dma_list_mutex);
827 rc = idr_alloc(&dma_idr, NULL, 0, 0, GFP_KERNEL);
831 mutex_unlock(&dma_list_mutex);
832 return rc < 0 ? rc : 0;
836 * dma_async_device_register - registers DMA devices found
837 * @device: &dma_device
839 int dma_async_device_register(struct dma_device *device)
842 struct dma_chan* chan;
848 /* validate device routines */
849 BUG_ON(dma_has_cap(DMA_MEMCPY, device->cap_mask) &&
850 !device->device_prep_dma_memcpy);
851 BUG_ON(dma_has_cap(DMA_XOR, device->cap_mask) &&
852 !device->device_prep_dma_xor);
853 BUG_ON(dma_has_cap(DMA_XOR_VAL, device->cap_mask) &&
854 !device->device_prep_dma_xor_val);
855 BUG_ON(dma_has_cap(DMA_PQ, device->cap_mask) &&
856 !device->device_prep_dma_pq);
857 BUG_ON(dma_has_cap(DMA_PQ_VAL, device->cap_mask) &&
858 !device->device_prep_dma_pq_val);
859 BUG_ON(dma_has_cap(DMA_MEMSET, device->cap_mask) &&
860 !device->device_prep_dma_memset);
861 BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) &&
862 !device->device_prep_dma_interrupt);
863 BUG_ON(dma_has_cap(DMA_SG, device->cap_mask) &&
864 !device->device_prep_dma_sg);
865 BUG_ON(dma_has_cap(DMA_CYCLIC, device->cap_mask) &&
866 !device->device_prep_dma_cyclic);
867 BUG_ON(dma_has_cap(DMA_INTERLEAVE, device->cap_mask) &&
868 !device->device_prep_interleaved_dma);
870 BUG_ON(!device->device_tx_status);
871 BUG_ON(!device->device_issue_pending);
872 BUG_ON(!device->dev);
874 /* note: this only matters in the
875 * CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH=n case
877 if (device_has_all_tx_types(device))
878 dma_cap_set(DMA_ASYNC_TX, device->cap_mask);
880 idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL);
883 rc = get_dma_id(device);
889 atomic_set(idr_ref, 0);
891 /* represent channels in sysfs. Probably want devs too */
892 list_for_each_entry(chan, &device->channels, device_node) {
894 chan->local = alloc_percpu(typeof(*chan->local));
895 if (chan->local == NULL)
897 chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
898 if (chan->dev == NULL) {
899 free_percpu(chan->local);
904 chan->chan_id = chancnt++;
905 chan->dev->device.class = &dma_devclass;
906 chan->dev->device.parent = device->dev;
907 chan->dev->chan = chan;
908 chan->dev->idr_ref = idr_ref;
909 chan->dev->dev_id = device->dev_id;
911 dev_set_name(&chan->dev->device, "dma%dchan%d",
912 device->dev_id, chan->chan_id);
914 rc = device_register(&chan->dev->device);
916 free_percpu(chan->local);
922 chan->client_count = 0;
924 device->chancnt = chancnt;
926 mutex_lock(&dma_list_mutex);
927 /* take references on public channels */
928 if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
929 list_for_each_entry(chan, &device->channels, device_node) {
930 /* if clients are already waiting for channels we need
931 * to take references on their behalf
933 if (dma_chan_get(chan) == -ENODEV) {
934 /* note we can only get here for the first
935 * channel as the remaining channels are
936 * guaranteed to get a reference
939 mutex_unlock(&dma_list_mutex);
943 list_add_tail_rcu(&device->global_node, &dma_device_list);
944 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
945 device->privatecnt++; /* Always private */
946 dma_channel_rebalance();
947 mutex_unlock(&dma_list_mutex);
952 /* if we never registered a channel just release the idr */
953 if (atomic_read(idr_ref) == 0) {
954 mutex_lock(&dma_list_mutex);
955 idr_remove(&dma_idr, device->dev_id);
956 mutex_unlock(&dma_list_mutex);
961 list_for_each_entry(chan, &device->channels, device_node) {
962 if (chan->local == NULL)
964 mutex_lock(&dma_list_mutex);
965 chan->dev->chan = NULL;
966 mutex_unlock(&dma_list_mutex);
967 device_unregister(&chan->dev->device);
968 free_percpu(chan->local);
972 EXPORT_SYMBOL(dma_async_device_register);
975 * dma_async_device_unregister - unregister a DMA device
976 * @device: &dma_device
978 * This routine is called by dma driver exit routines, dmaengine holds module
979 * references to prevent it being called while channels are in use.
981 void dma_async_device_unregister(struct dma_device *device)
983 struct dma_chan *chan;
985 mutex_lock(&dma_list_mutex);
986 list_del_rcu(&device->global_node);
987 dma_channel_rebalance();
988 mutex_unlock(&dma_list_mutex);
990 list_for_each_entry(chan, &device->channels, device_node) {
991 WARN_ONCE(chan->client_count,
992 "%s called while %d clients hold a reference\n",
993 __func__, chan->client_count);
994 mutex_lock(&dma_list_mutex);
995 chan->dev->chan = NULL;
996 mutex_unlock(&dma_list_mutex);
997 device_unregister(&chan->dev->device);
998 free_percpu(chan->local);
1001 EXPORT_SYMBOL(dma_async_device_unregister);
1003 struct dmaengine_unmap_pool {
1004 struct kmem_cache *cache;
1010 #define __UNMAP_POOL(x) { .size = x, .name = "dmaengine-unmap-" __stringify(x) }
1011 static struct dmaengine_unmap_pool unmap_pool[] = {
1013 #if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
1020 static struct dmaengine_unmap_pool *__get_unmap_pool(int nr)
1022 int order = get_count_order(nr);
1026 return &unmap_pool[0];
1028 return &unmap_pool[1];
1030 return &unmap_pool[2];
1032 return &unmap_pool[3];
1039 static void dmaengine_unmap(struct kref *kref)
1041 struct dmaengine_unmap_data *unmap = container_of(kref, typeof(*unmap), kref);
1042 struct device *dev = unmap->dev;
1045 cnt = unmap->to_cnt;
1046 for (i = 0; i < cnt; i++)
1047 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1049 cnt += unmap->from_cnt;
1050 for (; i < cnt; i++)
1051 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1053 cnt += unmap->bidi_cnt;
1054 for (; i < cnt; i++) {
1055 if (unmap->addr[i] == 0)
1057 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1060 cnt = unmap->map_cnt;
1061 mempool_free(unmap, __get_unmap_pool(cnt)->pool);
1064 void dmaengine_unmap_put(struct dmaengine_unmap_data *unmap)
1067 kref_put(&unmap->kref, dmaengine_unmap);
1069 EXPORT_SYMBOL_GPL(dmaengine_unmap_put);
1071 static void dmaengine_destroy_unmap_pool(void)
1075 for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
1076 struct dmaengine_unmap_pool *p = &unmap_pool[i];
1078 mempool_destroy(p->pool);
1080 kmem_cache_destroy(p->cache);
1085 static int __init dmaengine_init_unmap_pool(void)
1089 for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
1090 struct dmaengine_unmap_pool *p = &unmap_pool[i];
1093 size = sizeof(struct dmaengine_unmap_data) +
1094 sizeof(dma_addr_t) * p->size;
1096 p->cache = kmem_cache_create(p->name, size, 0,
1097 SLAB_HWCACHE_ALIGN, NULL);
1100 p->pool = mempool_create_slab_pool(1, p->cache);
1105 if (i == ARRAY_SIZE(unmap_pool))
1108 dmaengine_destroy_unmap_pool();
1112 struct dmaengine_unmap_data *
1113 dmaengine_get_unmap_data(struct device *dev, int nr, gfp_t flags)
1115 struct dmaengine_unmap_data *unmap;
1117 unmap = mempool_alloc(__get_unmap_pool(nr)->pool, flags);
1121 memset(unmap, 0, sizeof(*unmap));
1122 kref_init(&unmap->kref);
1124 unmap->map_cnt = nr;
1128 EXPORT_SYMBOL(dmaengine_get_unmap_data);
1130 void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
1131 struct dma_chan *chan)
1134 #ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
1135 spin_lock_init(&tx->lock);
1138 EXPORT_SYMBOL(dma_async_tx_descriptor_init);
1140 /* dma_wait_for_async_tx - spin wait for a transaction to complete
1141 * @tx: in-flight transaction to wait on
1144 dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
1146 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
1149 return DMA_COMPLETE;
1151 while (tx->cookie == -EBUSY) {
1152 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
1153 pr_err("%s timeout waiting for descriptor submission\n",
1159 return dma_sync_wait(tx->chan, tx->cookie);
1161 EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
1163 /* dma_run_dependencies - helper routine for dma drivers to process
1164 * (start) dependent operations on their target channel
1165 * @tx: transaction with dependencies
1167 void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
1169 struct dma_async_tx_descriptor *dep = txd_next(tx);
1170 struct dma_async_tx_descriptor *dep_next;
1171 struct dma_chan *chan;
1176 /* we'll submit tx->next now, so clear the link */
1180 /* keep submitting up until a channel switch is detected
1181 * in that case we will be called again as a result of
1182 * processing the interrupt from async_tx_channel_switch
1184 for (; dep; dep = dep_next) {
1186 txd_clear_parent(dep);
1187 dep_next = txd_next(dep);
1188 if (dep_next && dep_next->chan == chan)
1189 txd_clear_next(dep); /* ->next will be submitted */
1191 dep_next = NULL; /* submit current dep and terminate */
1194 dep->tx_submit(dep);
1197 chan->device->device_issue_pending(chan);
1199 EXPORT_SYMBOL_GPL(dma_run_dependencies);
1201 static int __init dma_bus_init(void)
1203 int err = dmaengine_init_unmap_pool();
1207 return class_register(&dma_devclass);
1209 arch_initcall(dma_bus_init);