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/driver-api/dmaengine for more details
44 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
46 #include <linux/platform_device.h>
47 #include <linux/dma-mapping.h>
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>
61 #include <linux/slab.h>
62 #include <linux/acpi.h>
63 #include <linux/acpi_dma.h>
64 #include <linux/of_dma.h>
65 #include <linux/mempool.h>
67 static DEFINE_MUTEX(dma_list_mutex);
68 static DEFINE_IDA(dma_ida);
69 static LIST_HEAD(dma_device_list);
70 static long dmaengine_ref_count;
72 /* --- sysfs implementation --- */
75 * dev_to_dma_chan - convert a device pointer to the its sysfs container object
78 * Must be called under dma_list_mutex
80 static struct dma_chan *dev_to_dma_chan(struct device *dev)
82 struct dma_chan_dev *chan_dev;
84 chan_dev = container_of(dev, typeof(*chan_dev), device);
85 return chan_dev->chan;
88 static ssize_t memcpy_count_show(struct device *dev,
89 struct device_attribute *attr, char *buf)
91 struct dma_chan *chan;
92 unsigned long count = 0;
96 mutex_lock(&dma_list_mutex);
97 chan = dev_to_dma_chan(dev);
99 for_each_possible_cpu(i)
100 count += per_cpu_ptr(chan->local, i)->memcpy_count;
101 err = sprintf(buf, "%lu\n", count);
104 mutex_unlock(&dma_list_mutex);
108 static DEVICE_ATTR_RO(memcpy_count);
110 static ssize_t bytes_transferred_show(struct device *dev,
111 struct device_attribute *attr, char *buf)
113 struct dma_chan *chan;
114 unsigned long count = 0;
118 mutex_lock(&dma_list_mutex);
119 chan = dev_to_dma_chan(dev);
121 for_each_possible_cpu(i)
122 count += per_cpu_ptr(chan->local, i)->bytes_transferred;
123 err = sprintf(buf, "%lu\n", count);
126 mutex_unlock(&dma_list_mutex);
130 static DEVICE_ATTR_RO(bytes_transferred);
132 static ssize_t in_use_show(struct device *dev, struct device_attribute *attr,
135 struct dma_chan *chan;
138 mutex_lock(&dma_list_mutex);
139 chan = dev_to_dma_chan(dev);
141 err = sprintf(buf, "%d\n", chan->client_count);
144 mutex_unlock(&dma_list_mutex);
148 static DEVICE_ATTR_RO(in_use);
150 static struct attribute *dma_dev_attrs[] = {
151 &dev_attr_memcpy_count.attr,
152 &dev_attr_bytes_transferred.attr,
153 &dev_attr_in_use.attr,
156 ATTRIBUTE_GROUPS(dma_dev);
158 static void chan_dev_release(struct device *dev)
160 struct dma_chan_dev *chan_dev;
162 chan_dev = container_of(dev, typeof(*chan_dev), device);
163 if (atomic_dec_and_test(chan_dev->idr_ref)) {
164 ida_free(&dma_ida, chan_dev->dev_id);
165 kfree(chan_dev->idr_ref);
170 static struct class dma_devclass = {
172 .dev_groups = dma_dev_groups,
173 .dev_release = chan_dev_release,
176 /* --- client and device registration --- */
178 #define dma_device_satisfies_mask(device, mask) \
179 __dma_device_satisfies_mask((device), &(mask))
181 __dma_device_satisfies_mask(struct dma_device *device,
182 const dma_cap_mask_t *want)
186 bitmap_and(has.bits, want->bits, device->cap_mask.bits,
188 return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END);
191 static struct module *dma_chan_to_owner(struct dma_chan *chan)
193 return chan->device->dev->driver->owner;
197 * balance_ref_count - catch up the channel reference count
198 * @chan - channel to balance ->client_count versus dmaengine_ref_count
200 * balance_ref_count must be called under dma_list_mutex
202 static void balance_ref_count(struct dma_chan *chan)
204 struct module *owner = dma_chan_to_owner(chan);
206 while (chan->client_count < dmaengine_ref_count) {
208 chan->client_count++;
213 * dma_chan_get - try to grab a dma channel's parent driver module
214 * @chan - channel to grab
216 * Must be called under dma_list_mutex
218 static int dma_chan_get(struct dma_chan *chan)
220 struct module *owner = dma_chan_to_owner(chan);
223 /* The channel is already in use, update client count */
224 if (chan->client_count) {
229 if (!try_module_get(owner))
232 /* allocate upon first client reference */
233 if (chan->device->device_alloc_chan_resources) {
234 ret = chan->device->device_alloc_chan_resources(chan);
239 if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
240 balance_ref_count(chan);
243 chan->client_count++;
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 /* This channel is not in use, bail out */
260 if (!chan->client_count)
263 chan->client_count--;
264 module_put(dma_chan_to_owner(chan));
266 /* This channel is not in use anymore, free it */
267 if (!chan->client_count && chan->device->device_free_chan_resources) {
268 /* Make sure all operations have completed */
269 dmaengine_synchronize(chan);
270 chan->device->device_free_chan_resources(chan);
273 /* If the channel is used via a DMA request router, free the mapping */
274 if (chan->router && chan->router->route_free) {
275 chan->router->route_free(chan->router->dev, chan->route_data);
277 chan->route_data = NULL;
281 enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
283 enum dma_status status;
284 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
286 dma_async_issue_pending(chan);
288 status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
289 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
290 dev_err(chan->device->dev, "%s: timeout!\n", __func__);
293 if (status != DMA_IN_PROGRESS)
300 EXPORT_SYMBOL(dma_sync_wait);
303 * dma_cap_mask_all - enable iteration over all operation types
305 static dma_cap_mask_t dma_cap_mask_all;
308 * dma_chan_tbl_ent - tracks channel allocations per core/operation
309 * @chan - associated channel for this entry
311 struct dma_chan_tbl_ent {
312 struct dma_chan *chan;
316 * channel_table - percpu lookup table for memory-to-memory offload providers
318 static struct dma_chan_tbl_ent __percpu *channel_table[DMA_TX_TYPE_END];
320 static int __init dma_channel_table_init(void)
322 enum dma_transaction_type cap;
325 bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END);
327 /* 'interrupt', 'private', and 'slave' are channel capabilities,
328 * but are not associated with an operation so they do not need
329 * an entry in the channel_table
331 clear_bit(DMA_INTERRUPT, dma_cap_mask_all.bits);
332 clear_bit(DMA_PRIVATE, dma_cap_mask_all.bits);
333 clear_bit(DMA_SLAVE, dma_cap_mask_all.bits);
335 for_each_dma_cap_mask(cap, dma_cap_mask_all) {
336 channel_table[cap] = alloc_percpu(struct dma_chan_tbl_ent);
337 if (!channel_table[cap]) {
344 pr_err("initialization failure\n");
345 for_each_dma_cap_mask(cap, dma_cap_mask_all)
346 free_percpu(channel_table[cap]);
351 arch_initcall(dma_channel_table_init);
354 * dma_find_channel - find a channel to carry out the operation
355 * @tx_type: transaction type
357 struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
359 return this_cpu_read(channel_table[tx_type]->chan);
361 EXPORT_SYMBOL(dma_find_channel);
364 * dma_issue_pending_all - flush all pending operations across all channels
366 void dma_issue_pending_all(void)
368 struct dma_device *device;
369 struct dma_chan *chan;
372 list_for_each_entry_rcu(device, &dma_device_list, global_node) {
373 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
375 list_for_each_entry(chan, &device->channels, device_node)
376 if (chan->client_count)
377 device->device_issue_pending(chan);
381 EXPORT_SYMBOL(dma_issue_pending_all);
384 * dma_chan_is_local - returns true if the channel is in the same numa-node as the cpu
386 static bool dma_chan_is_local(struct dma_chan *chan, int cpu)
388 int node = dev_to_node(chan->device->dev);
389 return node == -1 || cpumask_test_cpu(cpu, cpumask_of_node(node));
393 * min_chan - returns the channel with min count and in the same numa-node as the cpu
394 * @cap: capability to match
395 * @cpu: cpu index which the channel should be close to
397 * If some channels are close to the given cpu, the one with the lowest
398 * reference count is returned. Otherwise, cpu is ignored and only the
399 * reference count is taken into account.
400 * Must be called under dma_list_mutex.
402 static struct dma_chan *min_chan(enum dma_transaction_type cap, int cpu)
404 struct dma_device *device;
405 struct dma_chan *chan;
406 struct dma_chan *min = NULL;
407 struct dma_chan *localmin = NULL;
409 list_for_each_entry(device, &dma_device_list, global_node) {
410 if (!dma_has_cap(cap, device->cap_mask) ||
411 dma_has_cap(DMA_PRIVATE, device->cap_mask))
413 list_for_each_entry(chan, &device->channels, device_node) {
414 if (!chan->client_count)
416 if (!min || chan->table_count < min->table_count)
419 if (dma_chan_is_local(chan, cpu))
421 chan->table_count < localmin->table_count)
426 chan = localmin ? localmin : min;
435 * dma_channel_rebalance - redistribute the available channels
437 * Optimize for cpu isolation (each cpu gets a dedicated channel for an
438 * operation type) in the SMP case, and operation isolation (avoid
439 * multi-tasking channels) in the non-SMP case. Must be called under
442 static void dma_channel_rebalance(void)
444 struct dma_chan *chan;
445 struct dma_device *device;
449 /* undo the last distribution */
450 for_each_dma_cap_mask(cap, dma_cap_mask_all)
451 for_each_possible_cpu(cpu)
452 per_cpu_ptr(channel_table[cap], cpu)->chan = NULL;
454 list_for_each_entry(device, &dma_device_list, global_node) {
455 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
457 list_for_each_entry(chan, &device->channels, device_node)
458 chan->table_count = 0;
461 /* don't populate the channel_table if no clients are available */
462 if (!dmaengine_ref_count)
465 /* redistribute available channels */
466 for_each_dma_cap_mask(cap, dma_cap_mask_all)
467 for_each_online_cpu(cpu) {
468 chan = min_chan(cap, cpu);
469 per_cpu_ptr(channel_table[cap], cpu)->chan = chan;
473 int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps)
475 struct dma_device *device;
480 device = chan->device;
482 /* check if the channel supports slave transactions */
483 if (!(test_bit(DMA_SLAVE, device->cap_mask.bits) ||
484 test_bit(DMA_CYCLIC, 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;
500 caps->descriptor_reuse = device->descriptor_reuse;
503 * Some devices implement only pause (e.g. to get residuum) but no
504 * resume. However cmd_pause is advertised as pause AND resume.
506 caps->cmd_pause = !!(device->device_pause && device->device_resume);
507 caps->cmd_terminate = !!device->device_terminate_all;
511 EXPORT_SYMBOL_GPL(dma_get_slave_caps);
513 static struct dma_chan *private_candidate(const dma_cap_mask_t *mask,
514 struct dma_device *dev,
515 dma_filter_fn fn, void *fn_param)
517 struct dma_chan *chan;
519 if (mask && !__dma_device_satisfies_mask(dev, mask)) {
520 dev_dbg(dev->dev, "%s: wrong capabilities\n", __func__);
523 /* devices with multiple channels need special handling as we need to
524 * ensure that all channels are either private or public.
526 if (dev->chancnt > 1 && !dma_has_cap(DMA_PRIVATE, dev->cap_mask))
527 list_for_each_entry(chan, &dev->channels, device_node) {
528 /* some channels are already publicly allocated */
529 if (chan->client_count)
533 list_for_each_entry(chan, &dev->channels, device_node) {
534 if (chan->client_count) {
535 dev_dbg(dev->dev, "%s: %s busy\n",
536 __func__, dma_chan_name(chan));
539 if (fn && !fn(chan, fn_param)) {
540 dev_dbg(dev->dev, "%s: %s filter said false\n",
541 __func__, dma_chan_name(chan));
550 static struct dma_chan *find_candidate(struct dma_device *device,
551 const dma_cap_mask_t *mask,
552 dma_filter_fn fn, void *fn_param)
554 struct dma_chan *chan = private_candidate(mask, device, fn, fn_param);
558 /* Found a suitable channel, try to grab, prep, and return it.
559 * We first set DMA_PRIVATE to disable balance_ref_count as this
560 * channel will not be published in the general-purpose
563 dma_cap_set(DMA_PRIVATE, device->cap_mask);
564 device->privatecnt++;
565 err = dma_chan_get(chan);
568 if (err == -ENODEV) {
569 dev_dbg(device->dev, "%s: %s module removed\n",
570 __func__, dma_chan_name(chan));
571 list_del_rcu(&device->global_node);
574 "%s: failed to get %s: (%d)\n",
575 __func__, dma_chan_name(chan), err);
577 if (--device->privatecnt == 0)
578 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
584 return chan ? chan : ERR_PTR(-EPROBE_DEFER);
588 * dma_get_slave_channel - try to get specific channel exclusively
589 * @chan: target channel
591 struct dma_chan *dma_get_slave_channel(struct dma_chan *chan)
595 /* lock against __dma_request_channel */
596 mutex_lock(&dma_list_mutex);
598 if (chan->client_count == 0) {
599 struct dma_device *device = chan->device;
601 dma_cap_set(DMA_PRIVATE, device->cap_mask);
602 device->privatecnt++;
603 err = dma_chan_get(chan);
605 dev_dbg(chan->device->dev,
606 "%s: failed to get %s: (%d)\n",
607 __func__, dma_chan_name(chan), err);
609 if (--device->privatecnt == 0)
610 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
615 mutex_unlock(&dma_list_mutex);
620 EXPORT_SYMBOL_GPL(dma_get_slave_channel);
622 struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)
625 struct dma_chan *chan;
628 dma_cap_set(DMA_SLAVE, mask);
630 /* lock against __dma_request_channel */
631 mutex_lock(&dma_list_mutex);
633 chan = find_candidate(device, &mask, NULL, NULL);
635 mutex_unlock(&dma_list_mutex);
637 return IS_ERR(chan) ? NULL : chan;
639 EXPORT_SYMBOL_GPL(dma_get_any_slave_channel);
642 * __dma_request_channel - try to allocate an exclusive channel
643 * @mask: capabilities that the channel must satisfy
644 * @fn: optional callback to disposition available channels
645 * @fn_param: opaque parameter to pass to dma_filter_fn
647 * Returns pointer to appropriate DMA channel on success or NULL.
649 struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
650 dma_filter_fn fn, void *fn_param)
652 struct dma_device *device, *_d;
653 struct dma_chan *chan = NULL;
656 mutex_lock(&dma_list_mutex);
657 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
658 chan = find_candidate(device, mask, fn, fn_param);
664 mutex_unlock(&dma_list_mutex);
666 pr_debug("%s: %s (%s)\n",
668 chan ? "success" : "fail",
669 chan ? dma_chan_name(chan) : NULL);
673 EXPORT_SYMBOL_GPL(__dma_request_channel);
675 static const struct dma_slave_map *dma_filter_match(struct dma_device *device,
681 if (!device->filter.mapcnt)
684 for (i = 0; i < device->filter.mapcnt; i++) {
685 const struct dma_slave_map *map = &device->filter.map[i];
687 if (!strcmp(map->devname, dev_name(dev)) &&
688 !strcmp(map->slave, name))
696 * dma_request_chan - try to allocate an exclusive slave channel
697 * @dev: pointer to client device structure
698 * @name: slave channel name
700 * Returns pointer to appropriate DMA channel on success or an error pointer.
702 struct dma_chan *dma_request_chan(struct device *dev, const char *name)
704 struct dma_device *d, *_d;
705 struct dma_chan *chan = NULL;
707 /* If device-tree is present get slave info from here */
709 chan = of_dma_request_slave_channel(dev->of_node, name);
711 /* If device was enumerated by ACPI get slave info from here */
712 if (has_acpi_companion(dev) && !chan)
713 chan = acpi_dma_request_slave_chan_by_name(dev, name);
716 /* Valid channel found or requester need to be deferred */
717 if (!IS_ERR(chan) || PTR_ERR(chan) == -EPROBE_DEFER)
721 /* Try to find the channel via the DMA filter map(s) */
722 mutex_lock(&dma_list_mutex);
723 list_for_each_entry_safe(d, _d, &dma_device_list, global_node) {
725 const struct dma_slave_map *map = dma_filter_match(d, name, dev);
731 dma_cap_set(DMA_SLAVE, mask);
733 chan = find_candidate(d, &mask, d->filter.fn, map->param);
737 mutex_unlock(&dma_list_mutex);
739 return chan ? chan : ERR_PTR(-EPROBE_DEFER);
741 EXPORT_SYMBOL_GPL(dma_request_chan);
744 * dma_request_slave_channel - try to allocate an exclusive slave channel
745 * @dev: pointer to client device structure
746 * @name: slave channel name
748 * Returns pointer to appropriate DMA channel on success or NULL.
750 struct dma_chan *dma_request_slave_channel(struct device *dev,
753 struct dma_chan *ch = dma_request_chan(dev, name);
759 EXPORT_SYMBOL_GPL(dma_request_slave_channel);
762 * dma_request_chan_by_mask - allocate a channel satisfying certain capabilities
763 * @mask: capabilities that the channel must satisfy
765 * Returns pointer to appropriate DMA channel on success or an error pointer.
767 struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask)
769 struct dma_chan *chan;
772 return ERR_PTR(-ENODEV);
774 chan = __dma_request_channel(mask, NULL, NULL);
776 chan = ERR_PTR(-ENODEV);
780 EXPORT_SYMBOL_GPL(dma_request_chan_by_mask);
782 void dma_release_channel(struct dma_chan *chan)
784 mutex_lock(&dma_list_mutex);
785 WARN_ONCE(chan->client_count != 1,
786 "chan reference count %d != 1\n", chan->client_count);
788 /* drop PRIVATE cap enabled by __dma_request_channel() */
789 if (--chan->device->privatecnt == 0)
790 dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
791 mutex_unlock(&dma_list_mutex);
793 EXPORT_SYMBOL_GPL(dma_release_channel);
796 * dmaengine_get - register interest in dma_channels
798 void dmaengine_get(void)
800 struct dma_device *device, *_d;
801 struct dma_chan *chan;
804 mutex_lock(&dma_list_mutex);
805 dmaengine_ref_count++;
807 /* try to grab channels */
808 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
809 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
811 list_for_each_entry(chan, &device->channels, device_node) {
812 err = dma_chan_get(chan);
813 if (err == -ENODEV) {
814 /* module removed before we could use it */
815 list_del_rcu(&device->global_node);
818 dev_dbg(chan->device->dev,
819 "%s: failed to get %s: (%d)\n",
820 __func__, dma_chan_name(chan), err);
824 /* if this is the first reference and there were channels
825 * waiting we need to rebalance to get those channels
826 * incorporated into the channel table
828 if (dmaengine_ref_count == 1)
829 dma_channel_rebalance();
830 mutex_unlock(&dma_list_mutex);
832 EXPORT_SYMBOL(dmaengine_get);
835 * dmaengine_put - let dma drivers be removed when ref_count == 0
837 void dmaengine_put(void)
839 struct dma_device *device;
840 struct dma_chan *chan;
842 mutex_lock(&dma_list_mutex);
843 dmaengine_ref_count--;
844 BUG_ON(dmaengine_ref_count < 0);
845 /* drop channel references */
846 list_for_each_entry(device, &dma_device_list, global_node) {
847 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
849 list_for_each_entry(chan, &device->channels, device_node)
852 mutex_unlock(&dma_list_mutex);
854 EXPORT_SYMBOL(dmaengine_put);
856 static bool device_has_all_tx_types(struct dma_device *device)
858 /* A device that satisfies this test has channels that will never cause
859 * an async_tx channel switch event as all possible operation types can
862 #ifdef CONFIG_ASYNC_TX_DMA
863 if (!dma_has_cap(DMA_INTERRUPT, device->cap_mask))
867 #if IS_ENABLED(CONFIG_ASYNC_MEMCPY)
868 if (!dma_has_cap(DMA_MEMCPY, device->cap_mask))
872 #if IS_ENABLED(CONFIG_ASYNC_XOR)
873 if (!dma_has_cap(DMA_XOR, device->cap_mask))
876 #ifndef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
877 if (!dma_has_cap(DMA_XOR_VAL, device->cap_mask))
882 #if IS_ENABLED(CONFIG_ASYNC_PQ)
883 if (!dma_has_cap(DMA_PQ, device->cap_mask))
886 #ifndef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
887 if (!dma_has_cap(DMA_PQ_VAL, device->cap_mask))
895 static int get_dma_id(struct dma_device *device)
897 int rc = ida_alloc(&dma_ida, GFP_KERNEL);
906 * dma_async_device_register - registers DMA devices found
907 * @device: &dma_device
909 int dma_async_device_register(struct dma_device *device)
912 struct dma_chan* chan;
918 /* validate device routines */
920 pr_err("DMAdevice must have dev\n");
924 if (dma_has_cap(DMA_MEMCPY, device->cap_mask) && !device->device_prep_dma_memcpy) {
926 "Device claims capability %s, but op is not defined\n",
931 if (dma_has_cap(DMA_XOR, device->cap_mask) && !device->device_prep_dma_xor) {
933 "Device claims capability %s, but op is not defined\n",
938 if (dma_has_cap(DMA_XOR_VAL, device->cap_mask) && !device->device_prep_dma_xor_val) {
940 "Device claims capability %s, but op is not defined\n",
945 if (dma_has_cap(DMA_PQ, device->cap_mask) && !device->device_prep_dma_pq) {
947 "Device claims capability %s, but op is not defined\n",
952 if (dma_has_cap(DMA_PQ_VAL, device->cap_mask) && !device->device_prep_dma_pq_val) {
954 "Device claims capability %s, but op is not defined\n",
959 if (dma_has_cap(DMA_MEMSET, device->cap_mask) && !device->device_prep_dma_memset) {
961 "Device claims capability %s, but op is not defined\n",
966 if (dma_has_cap(DMA_INTERRUPT, device->cap_mask) && !device->device_prep_dma_interrupt) {
968 "Device claims capability %s, but op is not defined\n",
973 if (dma_has_cap(DMA_CYCLIC, device->cap_mask) && !device->device_prep_dma_cyclic) {
975 "Device claims capability %s, but op is not defined\n",
980 if (dma_has_cap(DMA_INTERLEAVE, device->cap_mask) && !device->device_prep_interleaved_dma) {
982 "Device claims capability %s, but op is not defined\n",
988 if (!device->device_tx_status) {
989 dev_err(device->dev, "Device tx_status is not defined\n");
994 if (!device->device_issue_pending) {
995 dev_err(device->dev, "Device issue_pending is not defined\n");
999 /* note: this only matters in the
1000 * CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH=n case
1002 if (device_has_all_tx_types(device))
1003 dma_cap_set(DMA_ASYNC_TX, device->cap_mask);
1005 idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL);
1008 rc = get_dma_id(device);
1014 atomic_set(idr_ref, 0);
1016 /* represent channels in sysfs. Probably want devs too */
1017 list_for_each_entry(chan, &device->channels, device_node) {
1019 chan->local = alloc_percpu(typeof(*chan->local));
1020 if (chan->local == NULL)
1022 chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
1023 if (chan->dev == NULL) {
1024 free_percpu(chan->local);
1029 chan->chan_id = chancnt++;
1030 chan->dev->device.class = &dma_devclass;
1031 chan->dev->device.parent = device->dev;
1032 chan->dev->chan = chan;
1033 chan->dev->idr_ref = idr_ref;
1034 chan->dev->dev_id = device->dev_id;
1035 atomic_inc(idr_ref);
1036 dev_set_name(&chan->dev->device, "dma%dchan%d",
1037 device->dev_id, chan->chan_id);
1039 rc = device_register(&chan->dev->device);
1041 free_percpu(chan->local);
1044 atomic_dec(idr_ref);
1047 chan->client_count = 0;
1051 dev_err(device->dev, "%s: device has no channels!\n", __func__);
1056 device->chancnt = chancnt;
1058 mutex_lock(&dma_list_mutex);
1059 /* take references on public channels */
1060 if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
1061 list_for_each_entry(chan, &device->channels, device_node) {
1062 /* if clients are already waiting for channels we need
1063 * to take references on their behalf
1065 if (dma_chan_get(chan) == -ENODEV) {
1066 /* note we can only get here for the first
1067 * channel as the remaining channels are
1068 * guaranteed to get a reference
1071 mutex_unlock(&dma_list_mutex);
1075 list_add_tail_rcu(&device->global_node, &dma_device_list);
1076 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
1077 device->privatecnt++; /* Always private */
1078 dma_channel_rebalance();
1079 mutex_unlock(&dma_list_mutex);
1084 /* if we never registered a channel just release the idr */
1085 if (atomic_read(idr_ref) == 0) {
1086 ida_free(&dma_ida, device->dev_id);
1091 list_for_each_entry(chan, &device->channels, device_node) {
1092 if (chan->local == NULL)
1094 mutex_lock(&dma_list_mutex);
1095 chan->dev->chan = NULL;
1096 mutex_unlock(&dma_list_mutex);
1097 device_unregister(&chan->dev->device);
1098 free_percpu(chan->local);
1102 EXPORT_SYMBOL(dma_async_device_register);
1105 * dma_async_device_unregister - unregister a DMA device
1106 * @device: &dma_device
1108 * This routine is called by dma driver exit routines, dmaengine holds module
1109 * references to prevent it being called while channels are in use.
1111 void dma_async_device_unregister(struct dma_device *device)
1113 struct dma_chan *chan;
1115 mutex_lock(&dma_list_mutex);
1116 list_del_rcu(&device->global_node);
1117 dma_channel_rebalance();
1118 mutex_unlock(&dma_list_mutex);
1120 list_for_each_entry(chan, &device->channels, device_node) {
1121 WARN_ONCE(chan->client_count,
1122 "%s called while %d clients hold a reference\n",
1123 __func__, chan->client_count);
1124 mutex_lock(&dma_list_mutex);
1125 chan->dev->chan = NULL;
1126 mutex_unlock(&dma_list_mutex);
1127 device_unregister(&chan->dev->device);
1128 free_percpu(chan->local);
1131 EXPORT_SYMBOL(dma_async_device_unregister);
1133 struct dmaengine_unmap_pool {
1134 struct kmem_cache *cache;
1140 #define __UNMAP_POOL(x) { .size = x, .name = "dmaengine-unmap-" __stringify(x) }
1141 static struct dmaengine_unmap_pool unmap_pool[] = {
1143 #if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
1150 static struct dmaengine_unmap_pool *__get_unmap_pool(int nr)
1152 int order = get_count_order(nr);
1156 return &unmap_pool[0];
1157 #if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
1159 return &unmap_pool[1];
1161 return &unmap_pool[2];
1163 return &unmap_pool[3];
1171 static void dmaengine_unmap(struct kref *kref)
1173 struct dmaengine_unmap_data *unmap = container_of(kref, typeof(*unmap), kref);
1174 struct device *dev = unmap->dev;
1177 cnt = unmap->to_cnt;
1178 for (i = 0; i < cnt; i++)
1179 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1181 cnt += unmap->from_cnt;
1182 for (; i < cnt; i++)
1183 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1185 cnt += unmap->bidi_cnt;
1186 for (; i < cnt; i++) {
1187 if (unmap->addr[i] == 0)
1189 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1192 cnt = unmap->map_cnt;
1193 mempool_free(unmap, __get_unmap_pool(cnt)->pool);
1196 void dmaengine_unmap_put(struct dmaengine_unmap_data *unmap)
1199 kref_put(&unmap->kref, dmaengine_unmap);
1201 EXPORT_SYMBOL_GPL(dmaengine_unmap_put);
1203 static void dmaengine_destroy_unmap_pool(void)
1207 for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
1208 struct dmaengine_unmap_pool *p = &unmap_pool[i];
1210 mempool_destroy(p->pool);
1212 kmem_cache_destroy(p->cache);
1217 static int __init dmaengine_init_unmap_pool(void)
1221 for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
1222 struct dmaengine_unmap_pool *p = &unmap_pool[i];
1225 size = sizeof(struct dmaengine_unmap_data) +
1226 sizeof(dma_addr_t) * p->size;
1228 p->cache = kmem_cache_create(p->name, size, 0,
1229 SLAB_HWCACHE_ALIGN, NULL);
1232 p->pool = mempool_create_slab_pool(1, p->cache);
1237 if (i == ARRAY_SIZE(unmap_pool))
1240 dmaengine_destroy_unmap_pool();
1244 struct dmaengine_unmap_data *
1245 dmaengine_get_unmap_data(struct device *dev, int nr, gfp_t flags)
1247 struct dmaengine_unmap_data *unmap;
1249 unmap = mempool_alloc(__get_unmap_pool(nr)->pool, flags);
1253 memset(unmap, 0, sizeof(*unmap));
1254 kref_init(&unmap->kref);
1256 unmap->map_cnt = nr;
1260 EXPORT_SYMBOL(dmaengine_get_unmap_data);
1262 void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
1263 struct dma_chan *chan)
1266 #ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
1267 spin_lock_init(&tx->lock);
1270 EXPORT_SYMBOL(dma_async_tx_descriptor_init);
1272 /* dma_wait_for_async_tx - spin wait for a transaction to complete
1273 * @tx: in-flight transaction to wait on
1276 dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
1278 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
1281 return DMA_COMPLETE;
1283 while (tx->cookie == -EBUSY) {
1284 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
1285 dev_err(tx->chan->device->dev,
1286 "%s timeout waiting for descriptor submission\n",
1292 return dma_sync_wait(tx->chan, tx->cookie);
1294 EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
1296 /* dma_run_dependencies - helper routine for dma drivers to process
1297 * (start) dependent operations on their target channel
1298 * @tx: transaction with dependencies
1300 void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
1302 struct dma_async_tx_descriptor *dep = txd_next(tx);
1303 struct dma_async_tx_descriptor *dep_next;
1304 struct dma_chan *chan;
1309 /* we'll submit tx->next now, so clear the link */
1313 /* keep submitting up until a channel switch is detected
1314 * in that case we will be called again as a result of
1315 * processing the interrupt from async_tx_channel_switch
1317 for (; dep; dep = dep_next) {
1319 txd_clear_parent(dep);
1320 dep_next = txd_next(dep);
1321 if (dep_next && dep_next->chan == chan)
1322 txd_clear_next(dep); /* ->next will be submitted */
1324 dep_next = NULL; /* submit current dep and terminate */
1327 dep->tx_submit(dep);
1330 chan->device->device_issue_pending(chan);
1332 EXPORT_SYMBOL_GPL(dma_run_dependencies);
1334 static int __init dma_bus_init(void)
1336 int err = dmaengine_init_unmap_pool();
1340 return class_register(&dma_devclass);
1342 arch_initcall(dma_bus_init);