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/of_dma.h>
67 static DEFINE_MUTEX(dma_list_mutex
);
68 static DEFINE_IDR(dma_idr
);
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
show_memcpy_count(struct device
*dev
, 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
);
108 static ssize_t
show_bytes_transferred(struct device
*dev
, struct device_attribute
*attr
,
111 struct dma_chan
*chan
;
112 unsigned long count
= 0;
116 mutex_lock(&dma_list_mutex
);
117 chan
= dev_to_dma_chan(dev
);
119 for_each_possible_cpu(i
)
120 count
+= per_cpu_ptr(chan
->local
, i
)->bytes_transferred
;
121 err
= sprintf(buf
, "%lu\n", count
);
124 mutex_unlock(&dma_list_mutex
);
129 static ssize_t
show_in_use(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
131 struct dma_chan
*chan
;
134 mutex_lock(&dma_list_mutex
);
135 chan
= dev_to_dma_chan(dev
);
137 err
= sprintf(buf
, "%d\n", chan
->client_count
);
140 mutex_unlock(&dma_list_mutex
);
145 static struct device_attribute dma_attrs
[] = {
146 __ATTR(memcpy_count
, S_IRUGO
, show_memcpy_count
, NULL
),
147 __ATTR(bytes_transferred
, S_IRUGO
, show_bytes_transferred
, NULL
),
148 __ATTR(in_use
, S_IRUGO
, show_in_use
, NULL
),
152 static void chan_dev_release(struct device
*dev
)
154 struct dma_chan_dev
*chan_dev
;
156 chan_dev
= container_of(dev
, typeof(*chan_dev
), device
);
157 if (atomic_dec_and_test(chan_dev
->idr_ref
)) {
158 mutex_lock(&dma_list_mutex
);
159 idr_remove(&dma_idr
, chan_dev
->dev_id
);
160 mutex_unlock(&dma_list_mutex
);
161 kfree(chan_dev
->idr_ref
);
166 static struct class dma_devclass
= {
168 .dev_attrs
= dma_attrs
,
169 .dev_release
= chan_dev_release
,
172 /* --- client and device registration --- */
174 #define dma_device_satisfies_mask(device, mask) \
175 __dma_device_satisfies_mask((device), &(mask))
177 __dma_device_satisfies_mask(struct dma_device
*device
, dma_cap_mask_t
*want
)
181 bitmap_and(has
.bits
, want
->bits
, device
->cap_mask
.bits
,
183 return bitmap_equal(want
->bits
, has
.bits
, DMA_TX_TYPE_END
);
186 static struct module
*dma_chan_to_owner(struct dma_chan
*chan
)
188 return chan
->device
->dev
->driver
->owner
;
192 * balance_ref_count - catch up the channel reference count
193 * @chan - channel to balance ->client_count versus dmaengine_ref_count
195 * balance_ref_count must be called under dma_list_mutex
197 static void balance_ref_count(struct dma_chan
*chan
)
199 struct module
*owner
= dma_chan_to_owner(chan
);
201 while (chan
->client_count
< dmaengine_ref_count
) {
203 chan
->client_count
++;
208 * dma_chan_get - try to grab a dma channel's parent driver module
209 * @chan - channel to grab
211 * Must be called under dma_list_mutex
213 static int dma_chan_get(struct dma_chan
*chan
)
216 struct module
*owner
= dma_chan_to_owner(chan
);
218 if (chan
->client_count
) {
221 } else if (try_module_get(owner
))
225 chan
->client_count
++;
227 /* allocate upon first client reference */
228 if (chan
->client_count
== 1 && err
== 0) {
229 int desc_cnt
= chan
->device
->device_alloc_chan_resources(chan
);
233 chan
->client_count
= 0;
235 } else if (!dma_has_cap(DMA_PRIVATE
, chan
->device
->cap_mask
))
236 balance_ref_count(chan
);
243 * dma_chan_put - drop a reference to a dma channel's parent driver module
244 * @chan - channel to release
246 * Must be called under dma_list_mutex
248 static void dma_chan_put(struct dma_chan
*chan
)
250 if (!chan
->client_count
)
251 return; /* this channel failed alloc_chan_resources */
252 chan
->client_count
--;
253 module_put(dma_chan_to_owner(chan
));
254 if (chan
->client_count
== 0)
255 chan
->device
->device_free_chan_resources(chan
);
258 enum dma_status
dma_sync_wait(struct dma_chan
*chan
, dma_cookie_t cookie
)
260 enum dma_status status
;
261 unsigned long dma_sync_wait_timeout
= jiffies
+ msecs_to_jiffies(5000);
263 dma_async_issue_pending(chan
);
265 status
= dma_async_is_tx_complete(chan
, cookie
, NULL
, NULL
);
266 if (time_after_eq(jiffies
, dma_sync_wait_timeout
)) {
267 pr_err("%s: timeout!\n", __func__
);
270 if (status
!= DMA_IN_PROGRESS
)
277 EXPORT_SYMBOL(dma_sync_wait
);
280 * dma_cap_mask_all - enable iteration over all operation types
282 static dma_cap_mask_t dma_cap_mask_all
;
285 * dma_chan_tbl_ent - tracks channel allocations per core/operation
286 * @chan - associated channel for this entry
288 struct dma_chan_tbl_ent
{
289 struct dma_chan
*chan
;
293 * channel_table - percpu lookup table for memory-to-memory offload providers
295 static struct dma_chan_tbl_ent __percpu
*channel_table
[DMA_TX_TYPE_END
];
297 static int __init
dma_channel_table_init(void)
299 enum dma_transaction_type cap
;
302 bitmap_fill(dma_cap_mask_all
.bits
, DMA_TX_TYPE_END
);
304 /* 'interrupt', 'private', and 'slave' are channel capabilities,
305 * but are not associated with an operation so they do not need
306 * an entry in the channel_table
308 clear_bit(DMA_INTERRUPT
, dma_cap_mask_all
.bits
);
309 clear_bit(DMA_PRIVATE
, dma_cap_mask_all
.bits
);
310 clear_bit(DMA_SLAVE
, dma_cap_mask_all
.bits
);
312 for_each_dma_cap_mask(cap
, dma_cap_mask_all
) {
313 channel_table
[cap
] = alloc_percpu(struct dma_chan_tbl_ent
);
314 if (!channel_table
[cap
]) {
321 pr_err("initialization failure\n");
322 for_each_dma_cap_mask(cap
, dma_cap_mask_all
)
323 if (channel_table
[cap
])
324 free_percpu(channel_table
[cap
]);
329 arch_initcall(dma_channel_table_init
);
332 * dma_find_channel - find a channel to carry out the operation
333 * @tx_type: transaction type
335 struct dma_chan
*dma_find_channel(enum dma_transaction_type tx_type
)
337 return this_cpu_read(channel_table
[tx_type
]->chan
);
339 EXPORT_SYMBOL(dma_find_channel
);
342 * net_dma_find_channel - find a channel for net_dma
343 * net_dma has alignment requirements
345 struct dma_chan
*net_dma_find_channel(void)
347 struct dma_chan
*chan
= dma_find_channel(DMA_MEMCPY
);
348 if (chan
&& !is_dma_copy_aligned(chan
->device
, 1, 1, 1))
353 EXPORT_SYMBOL(net_dma_find_channel
);
356 * dma_issue_pending_all - flush all pending operations across all channels
358 void dma_issue_pending_all(void)
360 struct dma_device
*device
;
361 struct dma_chan
*chan
;
364 list_for_each_entry_rcu(device
, &dma_device_list
, global_node
) {
365 if (dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
367 list_for_each_entry(chan
, &device
->channels
, device_node
)
368 if (chan
->client_count
)
369 device
->device_issue_pending(chan
);
373 EXPORT_SYMBOL(dma_issue_pending_all
);
376 * nth_chan - returns the nth channel of the given capability
377 * @cap: capability to match
378 * @n: nth channel desired
380 * Defaults to returning the channel with the desired capability and the
381 * lowest reference count when 'n' cannot be satisfied. Must be called
382 * under dma_list_mutex.
384 static struct dma_chan
*nth_chan(enum dma_transaction_type cap
, int n
)
386 struct dma_device
*device
;
387 struct dma_chan
*chan
;
388 struct dma_chan
*ret
= NULL
;
389 struct dma_chan
*min
= NULL
;
391 list_for_each_entry(device
, &dma_device_list
, global_node
) {
392 if (!dma_has_cap(cap
, device
->cap_mask
) ||
393 dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
395 list_for_each_entry(chan
, &device
->channels
, device_node
) {
396 if (!chan
->client_count
)
400 else if (chan
->table_count
< min
->table_count
)
422 * dma_channel_rebalance - redistribute the available channels
424 * Optimize for cpu isolation (each cpu gets a dedicated channel for an
425 * operation type) in the SMP case, and operation isolation (avoid
426 * multi-tasking channels) in the non-SMP case. Must be called under
429 static void dma_channel_rebalance(void)
431 struct dma_chan
*chan
;
432 struct dma_device
*device
;
437 /* undo the last distribution */
438 for_each_dma_cap_mask(cap
, dma_cap_mask_all
)
439 for_each_possible_cpu(cpu
)
440 per_cpu_ptr(channel_table
[cap
], cpu
)->chan
= NULL
;
442 list_for_each_entry(device
, &dma_device_list
, global_node
) {
443 if (dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
445 list_for_each_entry(chan
, &device
->channels
, device_node
)
446 chan
->table_count
= 0;
449 /* don't populate the channel_table if no clients are available */
450 if (!dmaengine_ref_count
)
453 /* redistribute available channels */
455 for_each_dma_cap_mask(cap
, dma_cap_mask_all
)
456 for_each_online_cpu(cpu
) {
457 if (num_possible_cpus() > 1)
458 chan
= nth_chan(cap
, n
++);
460 chan
= nth_chan(cap
, -1);
462 per_cpu_ptr(channel_table
[cap
], cpu
)->chan
= chan
;
466 static struct dma_chan
*private_candidate(dma_cap_mask_t
*mask
, struct dma_device
*dev
,
467 dma_filter_fn fn
, void *fn_param
)
469 struct dma_chan
*chan
;
471 if (!__dma_device_satisfies_mask(dev
, mask
)) {
472 pr_debug("%s: wrong capabilities\n", __func__
);
475 /* devices with multiple channels need special handling as we need to
476 * ensure that all channels are either private or public.
478 if (dev
->chancnt
> 1 && !dma_has_cap(DMA_PRIVATE
, dev
->cap_mask
))
479 list_for_each_entry(chan
, &dev
->channels
, device_node
) {
480 /* some channels are already publicly allocated */
481 if (chan
->client_count
)
485 list_for_each_entry(chan
, &dev
->channels
, device_node
) {
486 if (chan
->client_count
) {
487 pr_debug("%s: %s busy\n",
488 __func__
, dma_chan_name(chan
));
491 if (fn
&& !fn(chan
, fn_param
)) {
492 pr_debug("%s: %s filter said false\n",
493 __func__
, dma_chan_name(chan
));
503 * dma_request_channel - try to allocate an exclusive channel
504 * @mask: capabilities that the channel must satisfy
505 * @fn: optional callback to disposition available channels
506 * @fn_param: opaque parameter to pass to dma_filter_fn
508 struct dma_chan
*__dma_request_channel(dma_cap_mask_t
*mask
, dma_filter_fn fn
, void *fn_param
)
510 struct dma_device
*device
, *_d
;
511 struct dma_chan
*chan
= NULL
;
515 mutex_lock(&dma_list_mutex
);
516 list_for_each_entry_safe(device
, _d
, &dma_device_list
, global_node
) {
517 chan
= private_candidate(mask
, device
, fn
, fn_param
);
519 /* Found a suitable channel, try to grab, prep, and
520 * return it. We first set DMA_PRIVATE to disable
521 * balance_ref_count as this channel will not be
522 * published in the general-purpose allocator
524 dma_cap_set(DMA_PRIVATE
, device
->cap_mask
);
525 device
->privatecnt
++;
526 err
= dma_chan_get(chan
);
528 if (err
== -ENODEV
) {
529 pr_debug("%s: %s module removed\n",
530 __func__
, dma_chan_name(chan
));
531 list_del_rcu(&device
->global_node
);
533 pr_debug("%s: failed to get %s: (%d)\n",
534 __func__
, dma_chan_name(chan
), err
);
537 if (--device
->privatecnt
== 0)
538 dma_cap_clear(DMA_PRIVATE
, device
->cap_mask
);
542 mutex_unlock(&dma_list_mutex
);
544 pr_debug("%s: %s (%s)\n",
546 chan
? "success" : "fail",
547 chan
? dma_chan_name(chan
) : NULL
);
551 EXPORT_SYMBOL_GPL(__dma_request_channel
);
554 * dma_request_slave_channel - try to allocate an exclusive slave channel
555 * @dev: pointer to client device structure
556 * @name: slave channel name
558 struct dma_chan
*dma_request_slave_channel(struct device
*dev
, char *name
)
560 /* If device-tree is present get slave info from here */
562 return of_dma_request_slave_channel(dev
->of_node
, name
);
566 EXPORT_SYMBOL_GPL(dma_request_slave_channel
);
568 void dma_release_channel(struct dma_chan
*chan
)
570 mutex_lock(&dma_list_mutex
);
571 WARN_ONCE(chan
->client_count
!= 1,
572 "chan reference count %d != 1\n", chan
->client_count
);
574 /* drop PRIVATE cap enabled by __dma_request_channel() */
575 if (--chan
->device
->privatecnt
== 0)
576 dma_cap_clear(DMA_PRIVATE
, chan
->device
->cap_mask
);
577 mutex_unlock(&dma_list_mutex
);
579 EXPORT_SYMBOL_GPL(dma_release_channel
);
582 * dmaengine_get - register interest in dma_channels
584 void dmaengine_get(void)
586 struct dma_device
*device
, *_d
;
587 struct dma_chan
*chan
;
590 mutex_lock(&dma_list_mutex
);
591 dmaengine_ref_count
++;
593 /* try to grab channels */
594 list_for_each_entry_safe(device
, _d
, &dma_device_list
, global_node
) {
595 if (dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
597 list_for_each_entry(chan
, &device
->channels
, device_node
) {
598 err
= dma_chan_get(chan
);
599 if (err
== -ENODEV
) {
600 /* module removed before we could use it */
601 list_del_rcu(&device
->global_node
);
604 pr_debug("%s: failed to get %s: (%d)\n",
605 __func__
, dma_chan_name(chan
), err
);
609 /* if this is the first reference and there were channels
610 * waiting we need to rebalance to get those channels
611 * incorporated into the channel table
613 if (dmaengine_ref_count
== 1)
614 dma_channel_rebalance();
615 mutex_unlock(&dma_list_mutex
);
617 EXPORT_SYMBOL(dmaengine_get
);
620 * dmaengine_put - let dma drivers be removed when ref_count == 0
622 void dmaengine_put(void)
624 struct dma_device
*device
;
625 struct dma_chan
*chan
;
627 mutex_lock(&dma_list_mutex
);
628 dmaengine_ref_count
--;
629 BUG_ON(dmaengine_ref_count
< 0);
630 /* drop channel references */
631 list_for_each_entry(device
, &dma_device_list
, global_node
) {
632 if (dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
634 list_for_each_entry(chan
, &device
->channels
, device_node
)
637 mutex_unlock(&dma_list_mutex
);
639 EXPORT_SYMBOL(dmaengine_put
);
641 static bool device_has_all_tx_types(struct dma_device
*device
)
643 /* A device that satisfies this test has channels that will never cause
644 * an async_tx channel switch event as all possible operation types can
647 #ifdef CONFIG_ASYNC_TX_DMA
648 if (!dma_has_cap(DMA_INTERRUPT
, device
->cap_mask
))
652 #if defined(CONFIG_ASYNC_MEMCPY) || defined(CONFIG_ASYNC_MEMCPY_MODULE)
653 if (!dma_has_cap(DMA_MEMCPY
, device
->cap_mask
))
657 #if defined(CONFIG_ASYNC_MEMSET) || defined(CONFIG_ASYNC_MEMSET_MODULE)
658 if (!dma_has_cap(DMA_MEMSET
, device
->cap_mask
))
662 #if defined(CONFIG_ASYNC_XOR) || defined(CONFIG_ASYNC_XOR_MODULE)
663 if (!dma_has_cap(DMA_XOR
, device
->cap_mask
))
666 #ifndef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
667 if (!dma_has_cap(DMA_XOR_VAL
, device
->cap_mask
))
672 #if defined(CONFIG_ASYNC_PQ) || defined(CONFIG_ASYNC_PQ_MODULE)
673 if (!dma_has_cap(DMA_PQ
, device
->cap_mask
))
676 #ifndef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
677 if (!dma_has_cap(DMA_PQ_VAL
, device
->cap_mask
))
685 static int get_dma_id(struct dma_device
*device
)
689 mutex_lock(&dma_list_mutex
);
691 rc
= idr_alloc(&dma_idr
, NULL
, 0, 0, GFP_KERNEL
);
695 mutex_unlock(&dma_list_mutex
);
696 return rc
< 0 ? rc
: 0;
700 * dma_async_device_register - registers DMA devices found
701 * @device: &dma_device
703 int dma_async_device_register(struct dma_device
*device
)
706 struct dma_chan
* chan
;
712 /* validate device routines */
713 BUG_ON(dma_has_cap(DMA_MEMCPY
, device
->cap_mask
) &&
714 !device
->device_prep_dma_memcpy
);
715 BUG_ON(dma_has_cap(DMA_XOR
, device
->cap_mask
) &&
716 !device
->device_prep_dma_xor
);
717 BUG_ON(dma_has_cap(DMA_XOR_VAL
, device
->cap_mask
) &&
718 !device
->device_prep_dma_xor_val
);
719 BUG_ON(dma_has_cap(DMA_PQ
, device
->cap_mask
) &&
720 !device
->device_prep_dma_pq
);
721 BUG_ON(dma_has_cap(DMA_PQ_VAL
, device
->cap_mask
) &&
722 !device
->device_prep_dma_pq_val
);
723 BUG_ON(dma_has_cap(DMA_MEMSET
, device
->cap_mask
) &&
724 !device
->device_prep_dma_memset
);
725 BUG_ON(dma_has_cap(DMA_INTERRUPT
, device
->cap_mask
) &&
726 !device
->device_prep_dma_interrupt
);
727 BUG_ON(dma_has_cap(DMA_SG
, device
->cap_mask
) &&
728 !device
->device_prep_dma_sg
);
729 BUG_ON(dma_has_cap(DMA_CYCLIC
, device
->cap_mask
) &&
730 !device
->device_prep_dma_cyclic
);
731 BUG_ON(dma_has_cap(DMA_SLAVE
, device
->cap_mask
) &&
732 !device
->device_control
);
733 BUG_ON(dma_has_cap(DMA_INTERLEAVE
, device
->cap_mask
) &&
734 !device
->device_prep_interleaved_dma
);
736 BUG_ON(!device
->device_alloc_chan_resources
);
737 BUG_ON(!device
->device_free_chan_resources
);
738 BUG_ON(!device
->device_tx_status
);
739 BUG_ON(!device
->device_issue_pending
);
740 BUG_ON(!device
->dev
);
742 /* note: this only matters in the
743 * CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH=n case
745 if (device_has_all_tx_types(device
))
746 dma_cap_set(DMA_ASYNC_TX
, device
->cap_mask
);
748 idr_ref
= kmalloc(sizeof(*idr_ref
), GFP_KERNEL
);
751 rc
= get_dma_id(device
);
757 atomic_set(idr_ref
, 0);
759 /* represent channels in sysfs. Probably want devs too */
760 list_for_each_entry(chan
, &device
->channels
, device_node
) {
762 chan
->local
= alloc_percpu(typeof(*chan
->local
));
763 if (chan
->local
== NULL
)
765 chan
->dev
= kzalloc(sizeof(*chan
->dev
), GFP_KERNEL
);
766 if (chan
->dev
== NULL
) {
767 free_percpu(chan
->local
);
772 chan
->chan_id
= chancnt
++;
773 chan
->dev
->device
.class = &dma_devclass
;
774 chan
->dev
->device
.parent
= device
->dev
;
775 chan
->dev
->chan
= chan
;
776 chan
->dev
->idr_ref
= idr_ref
;
777 chan
->dev
->dev_id
= device
->dev_id
;
779 dev_set_name(&chan
->dev
->device
, "dma%dchan%d",
780 device
->dev_id
, chan
->chan_id
);
782 rc
= device_register(&chan
->dev
->device
);
784 free_percpu(chan
->local
);
790 chan
->client_count
= 0;
792 device
->chancnt
= chancnt
;
794 mutex_lock(&dma_list_mutex
);
795 /* take references on public channels */
796 if (dmaengine_ref_count
&& !dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
797 list_for_each_entry(chan
, &device
->channels
, device_node
) {
798 /* if clients are already waiting for channels we need
799 * to take references on their behalf
801 if (dma_chan_get(chan
) == -ENODEV
) {
802 /* note we can only get here for the first
803 * channel as the remaining channels are
804 * guaranteed to get a reference
807 mutex_unlock(&dma_list_mutex
);
811 list_add_tail_rcu(&device
->global_node
, &dma_device_list
);
812 if (dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
813 device
->privatecnt
++; /* Always private */
814 dma_channel_rebalance();
815 mutex_unlock(&dma_list_mutex
);
820 /* if we never registered a channel just release the idr */
821 if (atomic_read(idr_ref
) == 0) {
822 mutex_lock(&dma_list_mutex
);
823 idr_remove(&dma_idr
, device
->dev_id
);
824 mutex_unlock(&dma_list_mutex
);
829 list_for_each_entry(chan
, &device
->channels
, device_node
) {
830 if (chan
->local
== NULL
)
832 mutex_lock(&dma_list_mutex
);
833 chan
->dev
->chan
= NULL
;
834 mutex_unlock(&dma_list_mutex
);
835 device_unregister(&chan
->dev
->device
);
836 free_percpu(chan
->local
);
840 EXPORT_SYMBOL(dma_async_device_register
);
843 * dma_async_device_unregister - unregister a DMA device
844 * @device: &dma_device
846 * This routine is called by dma driver exit routines, dmaengine holds module
847 * references to prevent it being called while channels are in use.
849 void dma_async_device_unregister(struct dma_device
*device
)
851 struct dma_chan
*chan
;
853 mutex_lock(&dma_list_mutex
);
854 list_del_rcu(&device
->global_node
);
855 dma_channel_rebalance();
856 mutex_unlock(&dma_list_mutex
);
858 list_for_each_entry(chan
, &device
->channels
, device_node
) {
859 WARN_ONCE(chan
->client_count
,
860 "%s called while %d clients hold a reference\n",
861 __func__
, chan
->client_count
);
862 mutex_lock(&dma_list_mutex
);
863 chan
->dev
->chan
= NULL
;
864 mutex_unlock(&dma_list_mutex
);
865 device_unregister(&chan
->dev
->device
);
866 free_percpu(chan
->local
);
869 EXPORT_SYMBOL(dma_async_device_unregister
);
872 * dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
873 * @chan: DMA channel to offload copy to
874 * @dest: destination address (virtual)
875 * @src: source address (virtual)
878 * Both @dest and @src must be mappable to a bus address according to the
879 * DMA mapping API rules for streaming mappings.
880 * Both @dest and @src must stay memory resident (kernel memory or locked
884 dma_async_memcpy_buf_to_buf(struct dma_chan
*chan
, void *dest
,
885 void *src
, size_t len
)
887 struct dma_device
*dev
= chan
->device
;
888 struct dma_async_tx_descriptor
*tx
;
889 dma_addr_t dma_dest
, dma_src
;
893 dma_src
= dma_map_single(dev
->dev
, src
, len
, DMA_TO_DEVICE
);
894 dma_dest
= dma_map_single(dev
->dev
, dest
, len
, DMA_FROM_DEVICE
);
895 flags
= DMA_CTRL_ACK
|
896 DMA_COMPL_SRC_UNMAP_SINGLE
|
897 DMA_COMPL_DEST_UNMAP_SINGLE
;
898 tx
= dev
->device_prep_dma_memcpy(chan
, dma_dest
, dma_src
, len
, flags
);
901 dma_unmap_single(dev
->dev
, dma_src
, len
, DMA_TO_DEVICE
);
902 dma_unmap_single(dev
->dev
, dma_dest
, len
, DMA_FROM_DEVICE
);
907 cookie
= tx
->tx_submit(tx
);
910 __this_cpu_add(chan
->local
->bytes_transferred
, len
);
911 __this_cpu_inc(chan
->local
->memcpy_count
);
916 EXPORT_SYMBOL(dma_async_memcpy_buf_to_buf
);
919 * dma_async_memcpy_buf_to_pg - offloaded copy from address to page
920 * @chan: DMA channel to offload copy to
921 * @page: destination page
922 * @offset: offset in page to copy to
923 * @kdata: source address (virtual)
926 * Both @page/@offset and @kdata must be mappable to a bus address according
927 * to the DMA mapping API rules for streaming mappings.
928 * Both @page/@offset and @kdata must stay memory resident (kernel memory or
929 * locked user space pages)
932 dma_async_memcpy_buf_to_pg(struct dma_chan
*chan
, struct page
*page
,
933 unsigned int offset
, void *kdata
, size_t len
)
935 struct dma_device
*dev
= chan
->device
;
936 struct dma_async_tx_descriptor
*tx
;
937 dma_addr_t dma_dest
, dma_src
;
941 dma_src
= dma_map_single(dev
->dev
, kdata
, len
, DMA_TO_DEVICE
);
942 dma_dest
= dma_map_page(dev
->dev
, page
, offset
, len
, DMA_FROM_DEVICE
);
943 flags
= DMA_CTRL_ACK
| DMA_COMPL_SRC_UNMAP_SINGLE
;
944 tx
= dev
->device_prep_dma_memcpy(chan
, dma_dest
, dma_src
, len
, flags
);
947 dma_unmap_single(dev
->dev
, dma_src
, len
, DMA_TO_DEVICE
);
948 dma_unmap_page(dev
->dev
, dma_dest
, len
, DMA_FROM_DEVICE
);
953 cookie
= tx
->tx_submit(tx
);
956 __this_cpu_add(chan
->local
->bytes_transferred
, len
);
957 __this_cpu_inc(chan
->local
->memcpy_count
);
962 EXPORT_SYMBOL(dma_async_memcpy_buf_to_pg
);
965 * dma_async_memcpy_pg_to_pg - offloaded copy from page to page
966 * @chan: DMA channel to offload copy to
967 * @dest_pg: destination page
968 * @dest_off: offset in page to copy to
969 * @src_pg: source page
970 * @src_off: offset in page to copy from
973 * Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
974 * address according to the DMA mapping API rules for streaming mappings.
975 * Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
976 * (kernel memory or locked user space pages).
979 dma_async_memcpy_pg_to_pg(struct dma_chan
*chan
, struct page
*dest_pg
,
980 unsigned int dest_off
, struct page
*src_pg
, unsigned int src_off
,
983 struct dma_device
*dev
= chan
->device
;
984 struct dma_async_tx_descriptor
*tx
;
985 dma_addr_t dma_dest
, dma_src
;
989 dma_src
= dma_map_page(dev
->dev
, src_pg
, src_off
, len
, DMA_TO_DEVICE
);
990 dma_dest
= dma_map_page(dev
->dev
, dest_pg
, dest_off
, len
,
992 flags
= DMA_CTRL_ACK
;
993 tx
= dev
->device_prep_dma_memcpy(chan
, dma_dest
, dma_src
, len
, flags
);
996 dma_unmap_page(dev
->dev
, dma_src
, len
, DMA_TO_DEVICE
);
997 dma_unmap_page(dev
->dev
, dma_dest
, len
, DMA_FROM_DEVICE
);
1001 tx
->callback
= NULL
;
1002 cookie
= tx
->tx_submit(tx
);
1005 __this_cpu_add(chan
->local
->bytes_transferred
, len
);
1006 __this_cpu_inc(chan
->local
->memcpy_count
);
1011 EXPORT_SYMBOL(dma_async_memcpy_pg_to_pg
);
1013 void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor
*tx
,
1014 struct dma_chan
*chan
)
1017 #ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
1018 spin_lock_init(&tx
->lock
);
1021 EXPORT_SYMBOL(dma_async_tx_descriptor_init
);
1023 /* dma_wait_for_async_tx - spin wait for a transaction to complete
1024 * @tx: in-flight transaction to wait on
1027 dma_wait_for_async_tx(struct dma_async_tx_descriptor
*tx
)
1029 unsigned long dma_sync_wait_timeout
= jiffies
+ msecs_to_jiffies(5000);
1034 while (tx
->cookie
== -EBUSY
) {
1035 if (time_after_eq(jiffies
, dma_sync_wait_timeout
)) {
1036 pr_err("%s timeout waiting for descriptor submission\n",
1042 return dma_sync_wait(tx
->chan
, tx
->cookie
);
1044 EXPORT_SYMBOL_GPL(dma_wait_for_async_tx
);
1046 /* dma_run_dependencies - helper routine for dma drivers to process
1047 * (start) dependent operations on their target channel
1048 * @tx: transaction with dependencies
1050 void dma_run_dependencies(struct dma_async_tx_descriptor
*tx
)
1052 struct dma_async_tx_descriptor
*dep
= txd_next(tx
);
1053 struct dma_async_tx_descriptor
*dep_next
;
1054 struct dma_chan
*chan
;
1059 /* we'll submit tx->next now, so clear the link */
1063 /* keep submitting up until a channel switch is detected
1064 * in that case we will be called again as a result of
1065 * processing the interrupt from async_tx_channel_switch
1067 for (; dep
; dep
= dep_next
) {
1069 txd_clear_parent(dep
);
1070 dep_next
= txd_next(dep
);
1071 if (dep_next
&& dep_next
->chan
== chan
)
1072 txd_clear_next(dep
); /* ->next will be submitted */
1074 dep_next
= NULL
; /* submit current dep and terminate */
1077 dep
->tx_submit(dep
);
1080 chan
->device
->device_issue_pending(chan
);
1082 EXPORT_SYMBOL_GPL(dma_run_dependencies
);
1084 static int __init
dma_bus_init(void)
1086 return class_register(&dma_devclass
);
1088 arch_initcall(dma_bus_init
);