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 #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>
62 static DEFINE_MUTEX(dma_list_mutex
);
63 static LIST_HEAD(dma_device_list
);
64 static long dmaengine_ref_count
;
65 static struct idr dma_idr
;
67 /* --- sysfs implementation --- */
70 * dev_to_dma_chan - convert a device pointer to the its sysfs container object
73 * Must be called under dma_list_mutex
75 static struct dma_chan
*dev_to_dma_chan(struct device
*dev
)
77 struct dma_chan_dev
*chan_dev
;
79 chan_dev
= container_of(dev
, typeof(*chan_dev
), device
);
80 return chan_dev
->chan
;
83 static ssize_t
show_memcpy_count(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
85 struct dma_chan
*chan
;
86 unsigned long count
= 0;
90 mutex_lock(&dma_list_mutex
);
91 chan
= dev_to_dma_chan(dev
);
93 for_each_possible_cpu(i
)
94 count
+= per_cpu_ptr(chan
->local
, i
)->memcpy_count
;
95 err
= sprintf(buf
, "%lu\n", count
);
98 mutex_unlock(&dma_list_mutex
);
103 static ssize_t
show_bytes_transferred(struct device
*dev
, struct device_attribute
*attr
,
106 struct dma_chan
*chan
;
107 unsigned long count
= 0;
111 mutex_lock(&dma_list_mutex
);
112 chan
= dev_to_dma_chan(dev
);
114 for_each_possible_cpu(i
)
115 count
+= per_cpu_ptr(chan
->local
, i
)->bytes_transferred
;
116 err
= sprintf(buf
, "%lu\n", count
);
119 mutex_unlock(&dma_list_mutex
);
124 static ssize_t
show_in_use(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
126 struct dma_chan
*chan
;
129 mutex_lock(&dma_list_mutex
);
130 chan
= dev_to_dma_chan(dev
);
132 err
= sprintf(buf
, "%d\n", chan
->client_count
);
135 mutex_unlock(&dma_list_mutex
);
140 static struct device_attribute dma_attrs
[] = {
141 __ATTR(memcpy_count
, S_IRUGO
, show_memcpy_count
, NULL
),
142 __ATTR(bytes_transferred
, S_IRUGO
, show_bytes_transferred
, NULL
),
143 __ATTR(in_use
, S_IRUGO
, show_in_use
, NULL
),
147 static void chan_dev_release(struct device
*dev
)
149 struct dma_chan_dev
*chan_dev
;
151 chan_dev
= container_of(dev
, typeof(*chan_dev
), device
);
152 if (atomic_dec_and_test(chan_dev
->idr_ref
)) {
153 mutex_lock(&dma_list_mutex
);
154 idr_remove(&dma_idr
, chan_dev
->dev_id
);
155 mutex_unlock(&dma_list_mutex
);
156 kfree(chan_dev
->idr_ref
);
161 static struct class dma_devclass
= {
163 .dev_attrs
= dma_attrs
,
164 .dev_release
= chan_dev_release
,
167 /* --- client and device registration --- */
169 #define dma_device_satisfies_mask(device, mask) \
170 __dma_device_satisfies_mask((device), &(mask))
172 __dma_device_satisfies_mask(struct dma_device
*device
, dma_cap_mask_t
*want
)
176 bitmap_and(has
.bits
, want
->bits
, device
->cap_mask
.bits
,
178 return bitmap_equal(want
->bits
, has
.bits
, DMA_TX_TYPE_END
);
181 static struct module
*dma_chan_to_owner(struct dma_chan
*chan
)
183 return chan
->device
->dev
->driver
->owner
;
187 * balance_ref_count - catch up the channel reference count
188 * @chan - channel to balance ->client_count versus dmaengine_ref_count
190 * balance_ref_count must be called under dma_list_mutex
192 static void balance_ref_count(struct dma_chan
*chan
)
194 struct module
*owner
= dma_chan_to_owner(chan
);
196 while (chan
->client_count
< dmaengine_ref_count
) {
198 chan
->client_count
++;
203 * dma_chan_get - try to grab a dma channel's parent driver module
204 * @chan - channel to grab
206 * Must be called under dma_list_mutex
208 static int dma_chan_get(struct dma_chan
*chan
)
211 struct module
*owner
= dma_chan_to_owner(chan
);
213 if (chan
->client_count
) {
216 } else if (try_module_get(owner
))
220 chan
->client_count
++;
222 /* allocate upon first client reference */
223 if (chan
->client_count
== 1 && err
== 0) {
224 int desc_cnt
= chan
->device
->device_alloc_chan_resources(chan
);
228 chan
->client_count
= 0;
230 } else if (!dma_has_cap(DMA_PRIVATE
, chan
->device
->cap_mask
))
231 balance_ref_count(chan
);
238 * dma_chan_put - drop a reference to a dma channel's parent driver module
239 * @chan - channel to release
241 * Must be called under dma_list_mutex
243 static void dma_chan_put(struct dma_chan
*chan
)
245 if (!chan
->client_count
)
246 return; /* this channel failed alloc_chan_resources */
247 chan
->client_count
--;
248 module_put(dma_chan_to_owner(chan
));
249 if (chan
->client_count
== 0)
250 chan
->device
->device_free_chan_resources(chan
);
253 enum dma_status
dma_sync_wait(struct dma_chan
*chan
, dma_cookie_t cookie
)
255 enum dma_status status
;
256 unsigned long dma_sync_wait_timeout
= jiffies
+ msecs_to_jiffies(5000);
258 dma_async_issue_pending(chan
);
260 status
= dma_async_is_tx_complete(chan
, cookie
, NULL
, NULL
);
261 if (time_after_eq(jiffies
, dma_sync_wait_timeout
)) {
262 printk(KERN_ERR
"dma_sync_wait_timeout!\n");
265 } while (status
== DMA_IN_PROGRESS
);
269 EXPORT_SYMBOL(dma_sync_wait
);
272 * dma_cap_mask_all - enable iteration over all operation types
274 static dma_cap_mask_t dma_cap_mask_all
;
277 * dma_chan_tbl_ent - tracks channel allocations per core/operation
278 * @chan - associated channel for this entry
280 struct dma_chan_tbl_ent
{
281 struct dma_chan
*chan
;
285 * channel_table - percpu lookup table for memory-to-memory offload providers
287 static struct dma_chan_tbl_ent
*channel_table
[DMA_TX_TYPE_END
];
289 static int __init
dma_channel_table_init(void)
291 enum dma_transaction_type cap
;
294 bitmap_fill(dma_cap_mask_all
.bits
, DMA_TX_TYPE_END
);
296 /* 'interrupt', 'private', and 'slave' are channel capabilities,
297 * but are not associated with an operation so they do not need
298 * an entry in the channel_table
300 clear_bit(DMA_INTERRUPT
, dma_cap_mask_all
.bits
);
301 clear_bit(DMA_PRIVATE
, dma_cap_mask_all
.bits
);
302 clear_bit(DMA_SLAVE
, dma_cap_mask_all
.bits
);
304 for_each_dma_cap_mask(cap
, dma_cap_mask_all
) {
305 channel_table
[cap
] = alloc_percpu(struct dma_chan_tbl_ent
);
306 if (!channel_table
[cap
]) {
313 pr_err("dmaengine: initialization failure\n");
314 for_each_dma_cap_mask(cap
, dma_cap_mask_all
)
315 if (channel_table
[cap
])
316 free_percpu(channel_table
[cap
]);
321 arch_initcall(dma_channel_table_init
);
324 * dma_find_channel - find a channel to carry out the operation
325 * @tx_type: transaction type
327 struct dma_chan
*dma_find_channel(enum dma_transaction_type tx_type
)
329 struct dma_chan
*chan
;
332 WARN_ONCE(dmaengine_ref_count
== 0,
333 "client called %s without a reference", __func__
);
336 chan
= per_cpu_ptr(channel_table
[tx_type
], cpu
)->chan
;
341 EXPORT_SYMBOL(dma_find_channel
);
344 * dma_issue_pending_all - flush all pending operations across all channels
346 void dma_issue_pending_all(void)
348 struct dma_device
*device
;
349 struct dma_chan
*chan
;
351 WARN_ONCE(dmaengine_ref_count
== 0,
352 "client called %s without a reference", __func__
);
355 list_for_each_entry_rcu(device
, &dma_device_list
, global_node
) {
356 if (dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
358 list_for_each_entry(chan
, &device
->channels
, device_node
)
359 if (chan
->client_count
)
360 device
->device_issue_pending(chan
);
364 EXPORT_SYMBOL(dma_issue_pending_all
);
367 * nth_chan - returns the nth channel of the given capability
368 * @cap: capability to match
369 * @n: nth channel desired
371 * Defaults to returning the channel with the desired capability and the
372 * lowest reference count when 'n' cannot be satisfied. Must be called
373 * under dma_list_mutex.
375 static struct dma_chan
*nth_chan(enum dma_transaction_type cap
, int n
)
377 struct dma_device
*device
;
378 struct dma_chan
*chan
;
379 struct dma_chan
*ret
= NULL
;
380 struct dma_chan
*min
= NULL
;
382 list_for_each_entry(device
, &dma_device_list
, global_node
) {
383 if (!dma_has_cap(cap
, device
->cap_mask
) ||
384 dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
386 list_for_each_entry(chan
, &device
->channels
, device_node
) {
387 if (!chan
->client_count
)
391 else if (chan
->table_count
< min
->table_count
)
413 * dma_channel_rebalance - redistribute the available channels
415 * Optimize for cpu isolation (each cpu gets a dedicated channel for an
416 * operation type) in the SMP case, and operation isolation (avoid
417 * multi-tasking channels) in the non-SMP case. Must be called under
420 static void dma_channel_rebalance(void)
422 struct dma_chan
*chan
;
423 struct dma_device
*device
;
428 /* undo the last distribution */
429 for_each_dma_cap_mask(cap
, dma_cap_mask_all
)
430 for_each_possible_cpu(cpu
)
431 per_cpu_ptr(channel_table
[cap
], cpu
)->chan
= NULL
;
433 list_for_each_entry(device
, &dma_device_list
, global_node
) {
434 if (dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
436 list_for_each_entry(chan
, &device
->channels
, device_node
)
437 chan
->table_count
= 0;
440 /* don't populate the channel_table if no clients are available */
441 if (!dmaengine_ref_count
)
444 /* redistribute available channels */
446 for_each_dma_cap_mask(cap
, dma_cap_mask_all
)
447 for_each_online_cpu(cpu
) {
448 if (num_possible_cpus() > 1)
449 chan
= nth_chan(cap
, n
++);
451 chan
= nth_chan(cap
, -1);
453 per_cpu_ptr(channel_table
[cap
], cpu
)->chan
= chan
;
457 static struct dma_chan
*private_candidate(dma_cap_mask_t
*mask
, struct dma_device
*dev
,
458 dma_filter_fn fn
, void *fn_param
)
460 struct dma_chan
*chan
;
462 if (!__dma_device_satisfies_mask(dev
, mask
)) {
463 pr_debug("%s: wrong capabilities\n", __func__
);
466 /* devices with multiple channels need special handling as we need to
467 * ensure that all channels are either private or public.
469 if (dev
->chancnt
> 1 && !dma_has_cap(DMA_PRIVATE
, dev
->cap_mask
))
470 list_for_each_entry(chan
, &dev
->channels
, device_node
) {
471 /* some channels are already publicly allocated */
472 if (chan
->client_count
)
476 list_for_each_entry(chan
, &dev
->channels
, device_node
) {
477 if (chan
->client_count
) {
478 pr_debug("%s: %s busy\n",
479 __func__
, dma_chan_name(chan
));
482 if (fn
&& !fn(chan
, fn_param
)) {
483 pr_debug("%s: %s filter said false\n",
484 __func__
, dma_chan_name(chan
));
494 * dma_request_channel - try to allocate an exclusive channel
495 * @mask: capabilities that the channel must satisfy
496 * @fn: optional callback to disposition available channels
497 * @fn_param: opaque parameter to pass to dma_filter_fn
499 struct dma_chan
*__dma_request_channel(dma_cap_mask_t
*mask
, dma_filter_fn fn
, void *fn_param
)
501 struct dma_device
*device
, *_d
;
502 struct dma_chan
*chan
= NULL
;
506 mutex_lock(&dma_list_mutex
);
507 list_for_each_entry_safe(device
, _d
, &dma_device_list
, global_node
) {
508 chan
= private_candidate(mask
, device
, fn
, fn_param
);
510 /* Found a suitable channel, try to grab, prep, and
511 * return it. We first set DMA_PRIVATE to disable
512 * balance_ref_count as this channel will not be
513 * published in the general-purpose allocator
515 dma_cap_set(DMA_PRIVATE
, device
->cap_mask
);
516 err
= dma_chan_get(chan
);
518 if (err
== -ENODEV
) {
519 pr_debug("%s: %s module removed\n", __func__
,
520 dma_chan_name(chan
));
521 list_del_rcu(&device
->global_node
);
523 pr_err("dmaengine: failed to get %s: (%d)\n",
524 dma_chan_name(chan
), err
);
530 mutex_unlock(&dma_list_mutex
);
532 pr_debug("%s: %s (%s)\n", __func__
, chan
? "success" : "fail",
533 chan
? dma_chan_name(chan
) : NULL
);
537 EXPORT_SYMBOL_GPL(__dma_request_channel
);
539 void dma_release_channel(struct dma_chan
*chan
)
541 mutex_lock(&dma_list_mutex
);
542 WARN_ONCE(chan
->client_count
!= 1,
543 "chan reference count %d != 1\n", chan
->client_count
);
545 mutex_unlock(&dma_list_mutex
);
547 EXPORT_SYMBOL_GPL(dma_release_channel
);
550 * dmaengine_get - register interest in dma_channels
552 void dmaengine_get(void)
554 struct dma_device
*device
, *_d
;
555 struct dma_chan
*chan
;
558 mutex_lock(&dma_list_mutex
);
559 dmaengine_ref_count
++;
561 /* try to grab channels */
562 list_for_each_entry_safe(device
, _d
, &dma_device_list
, global_node
) {
563 if (dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
565 list_for_each_entry(chan
, &device
->channels
, device_node
) {
566 err
= dma_chan_get(chan
);
567 if (err
== -ENODEV
) {
568 /* module removed before we could use it */
569 list_del_rcu(&device
->global_node
);
572 pr_err("dmaengine: failed to get %s: (%d)\n",
573 dma_chan_name(chan
), err
);
577 /* if this is the first reference and there were channels
578 * waiting we need to rebalance to get those channels
579 * incorporated into the channel table
581 if (dmaengine_ref_count
== 1)
582 dma_channel_rebalance();
583 mutex_unlock(&dma_list_mutex
);
585 EXPORT_SYMBOL(dmaengine_get
);
588 * dmaengine_put - let dma drivers be removed when ref_count == 0
590 void dmaengine_put(void)
592 struct dma_device
*device
;
593 struct dma_chan
*chan
;
595 mutex_lock(&dma_list_mutex
);
596 dmaengine_ref_count
--;
597 BUG_ON(dmaengine_ref_count
< 0);
598 /* drop channel references */
599 list_for_each_entry(device
, &dma_device_list
, global_node
) {
600 if (dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
602 list_for_each_entry(chan
, &device
->channels
, device_node
)
605 mutex_unlock(&dma_list_mutex
);
607 EXPORT_SYMBOL(dmaengine_put
);
610 * dma_async_device_register - registers DMA devices found
611 * @device: &dma_device
613 int dma_async_device_register(struct dma_device
*device
)
616 struct dma_chan
* chan
;
622 /* validate device routines */
623 BUG_ON(dma_has_cap(DMA_MEMCPY
, device
->cap_mask
) &&
624 !device
->device_prep_dma_memcpy
);
625 BUG_ON(dma_has_cap(DMA_XOR
, device
->cap_mask
) &&
626 !device
->device_prep_dma_xor
);
627 BUG_ON(dma_has_cap(DMA_ZERO_SUM
, device
->cap_mask
) &&
628 !device
->device_prep_dma_zero_sum
);
629 BUG_ON(dma_has_cap(DMA_MEMSET
, device
->cap_mask
) &&
630 !device
->device_prep_dma_memset
);
631 BUG_ON(dma_has_cap(DMA_INTERRUPT
, device
->cap_mask
) &&
632 !device
->device_prep_dma_interrupt
);
633 BUG_ON(dma_has_cap(DMA_SLAVE
, device
->cap_mask
) &&
634 !device
->device_prep_slave_sg
);
635 BUG_ON(dma_has_cap(DMA_SLAVE
, device
->cap_mask
) &&
636 !device
->device_terminate_all
);
638 BUG_ON(!device
->device_alloc_chan_resources
);
639 BUG_ON(!device
->device_free_chan_resources
);
640 BUG_ON(!device
->device_is_tx_complete
);
641 BUG_ON(!device
->device_issue_pending
);
642 BUG_ON(!device
->dev
);
644 idr_ref
= kmalloc(sizeof(*idr_ref
), GFP_KERNEL
);
647 atomic_set(idr_ref
, 0);
649 if (!idr_pre_get(&dma_idr
, GFP_KERNEL
))
651 mutex_lock(&dma_list_mutex
);
652 rc
= idr_get_new(&dma_idr
, NULL
, &device
->dev_id
);
653 mutex_unlock(&dma_list_mutex
);
659 /* represent channels in sysfs. Probably want devs too */
660 list_for_each_entry(chan
, &device
->channels
, device_node
) {
661 chan
->local
= alloc_percpu(typeof(*chan
->local
));
662 if (chan
->local
== NULL
)
664 chan
->dev
= kzalloc(sizeof(*chan
->dev
), GFP_KERNEL
);
665 if (chan
->dev
== NULL
) {
666 free_percpu(chan
->local
);
670 chan
->chan_id
= chancnt
++;
671 chan
->dev
->device
.class = &dma_devclass
;
672 chan
->dev
->device
.parent
= device
->dev
;
673 chan
->dev
->chan
= chan
;
674 chan
->dev
->idr_ref
= idr_ref
;
675 chan
->dev
->dev_id
= device
->dev_id
;
677 dev_set_name(&chan
->dev
->device
, "dma%dchan%d",
678 device
->dev_id
, chan
->chan_id
);
680 rc
= device_register(&chan
->dev
->device
);
682 free_percpu(chan
->local
);
686 chan
->client_count
= 0;
688 device
->chancnt
= chancnt
;
690 mutex_lock(&dma_list_mutex
);
691 /* take references on public channels */
692 if (dmaengine_ref_count
&& !dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
693 list_for_each_entry(chan
, &device
->channels
, device_node
) {
694 /* if clients are already waiting for channels we need
695 * to take references on their behalf
697 if (dma_chan_get(chan
) == -ENODEV
) {
698 /* note we can only get here for the first
699 * channel as the remaining channels are
700 * guaranteed to get a reference
703 mutex_unlock(&dma_list_mutex
);
707 list_add_tail_rcu(&device
->global_node
, &dma_device_list
);
708 dma_channel_rebalance();
709 mutex_unlock(&dma_list_mutex
);
714 list_for_each_entry(chan
, &device
->channels
, device_node
) {
715 if (chan
->local
== NULL
)
717 mutex_lock(&dma_list_mutex
);
718 chan
->dev
->chan
= NULL
;
719 mutex_unlock(&dma_list_mutex
);
720 device_unregister(&chan
->dev
->device
);
721 free_percpu(chan
->local
);
725 EXPORT_SYMBOL(dma_async_device_register
);
728 * dma_async_device_unregister - unregister a DMA device
729 * @device: &dma_device
731 * This routine is called by dma driver exit routines, dmaengine holds module
732 * references to prevent it being called while channels are in use.
734 void dma_async_device_unregister(struct dma_device
*device
)
736 struct dma_chan
*chan
;
738 mutex_lock(&dma_list_mutex
);
739 list_del_rcu(&device
->global_node
);
740 dma_channel_rebalance();
741 mutex_unlock(&dma_list_mutex
);
743 list_for_each_entry(chan
, &device
->channels
, device_node
) {
744 WARN_ONCE(chan
->client_count
,
745 "%s called while %d clients hold a reference\n",
746 __func__
, chan
->client_count
);
747 mutex_lock(&dma_list_mutex
);
748 chan
->dev
->chan
= NULL
;
749 mutex_unlock(&dma_list_mutex
);
750 device_unregister(&chan
->dev
->device
);
753 EXPORT_SYMBOL(dma_async_device_unregister
);
756 * dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
757 * @chan: DMA channel to offload copy to
758 * @dest: destination address (virtual)
759 * @src: source address (virtual)
762 * Both @dest and @src must be mappable to a bus address according to the
763 * DMA mapping API rules for streaming mappings.
764 * Both @dest and @src must stay memory resident (kernel memory or locked
768 dma_async_memcpy_buf_to_buf(struct dma_chan
*chan
, void *dest
,
769 void *src
, size_t len
)
771 struct dma_device
*dev
= chan
->device
;
772 struct dma_async_tx_descriptor
*tx
;
773 dma_addr_t dma_dest
, dma_src
;
777 dma_src
= dma_map_single(dev
->dev
, src
, len
, DMA_TO_DEVICE
);
778 dma_dest
= dma_map_single(dev
->dev
, dest
, len
, DMA_FROM_DEVICE
);
779 tx
= dev
->device_prep_dma_memcpy(chan
, dma_dest
, dma_src
, len
,
783 dma_unmap_single(dev
->dev
, dma_src
, len
, DMA_TO_DEVICE
);
784 dma_unmap_single(dev
->dev
, dma_dest
, len
, DMA_FROM_DEVICE
);
789 cookie
= tx
->tx_submit(tx
);
792 per_cpu_ptr(chan
->local
, cpu
)->bytes_transferred
+= len
;
793 per_cpu_ptr(chan
->local
, cpu
)->memcpy_count
++;
798 EXPORT_SYMBOL(dma_async_memcpy_buf_to_buf
);
801 * dma_async_memcpy_buf_to_pg - offloaded copy from address to page
802 * @chan: DMA channel to offload copy to
803 * @page: destination page
804 * @offset: offset in page to copy to
805 * @kdata: source address (virtual)
808 * Both @page/@offset and @kdata must be mappable to a bus address according
809 * to the DMA mapping API rules for streaming mappings.
810 * Both @page/@offset and @kdata must stay memory resident (kernel memory or
811 * locked user space pages)
814 dma_async_memcpy_buf_to_pg(struct dma_chan
*chan
, struct page
*page
,
815 unsigned int offset
, void *kdata
, size_t len
)
817 struct dma_device
*dev
= chan
->device
;
818 struct dma_async_tx_descriptor
*tx
;
819 dma_addr_t dma_dest
, dma_src
;
823 dma_src
= dma_map_single(dev
->dev
, kdata
, len
, DMA_TO_DEVICE
);
824 dma_dest
= dma_map_page(dev
->dev
, page
, offset
, len
, DMA_FROM_DEVICE
);
825 tx
= dev
->device_prep_dma_memcpy(chan
, dma_dest
, dma_src
, len
,
829 dma_unmap_single(dev
->dev
, dma_src
, len
, DMA_TO_DEVICE
);
830 dma_unmap_page(dev
->dev
, dma_dest
, len
, DMA_FROM_DEVICE
);
835 cookie
= tx
->tx_submit(tx
);
838 per_cpu_ptr(chan
->local
, cpu
)->bytes_transferred
+= len
;
839 per_cpu_ptr(chan
->local
, cpu
)->memcpy_count
++;
844 EXPORT_SYMBOL(dma_async_memcpy_buf_to_pg
);
847 * dma_async_memcpy_pg_to_pg - offloaded copy from page to page
848 * @chan: DMA channel to offload copy to
849 * @dest_pg: destination page
850 * @dest_off: offset in page to copy to
851 * @src_pg: source page
852 * @src_off: offset in page to copy from
855 * Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
856 * address according to the DMA mapping API rules for streaming mappings.
857 * Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
858 * (kernel memory or locked user space pages).
861 dma_async_memcpy_pg_to_pg(struct dma_chan
*chan
, struct page
*dest_pg
,
862 unsigned int dest_off
, struct page
*src_pg
, unsigned int src_off
,
865 struct dma_device
*dev
= chan
->device
;
866 struct dma_async_tx_descriptor
*tx
;
867 dma_addr_t dma_dest
, dma_src
;
871 dma_src
= dma_map_page(dev
->dev
, src_pg
, src_off
, len
, DMA_TO_DEVICE
);
872 dma_dest
= dma_map_page(dev
->dev
, dest_pg
, dest_off
, len
,
874 tx
= dev
->device_prep_dma_memcpy(chan
, dma_dest
, dma_src
, len
,
878 dma_unmap_page(dev
->dev
, dma_src
, len
, DMA_TO_DEVICE
);
879 dma_unmap_page(dev
->dev
, dma_dest
, len
, DMA_FROM_DEVICE
);
884 cookie
= tx
->tx_submit(tx
);
887 per_cpu_ptr(chan
->local
, cpu
)->bytes_transferred
+= len
;
888 per_cpu_ptr(chan
->local
, cpu
)->memcpy_count
++;
893 EXPORT_SYMBOL(dma_async_memcpy_pg_to_pg
);
895 void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor
*tx
,
896 struct dma_chan
*chan
)
899 spin_lock_init(&tx
->lock
);
901 EXPORT_SYMBOL(dma_async_tx_descriptor_init
);
903 /* dma_wait_for_async_tx - spin wait for a transaction to complete
904 * @tx: in-flight transaction to wait on
906 * This routine assumes that tx was obtained from a call to async_memcpy,
907 * async_xor, async_memset, etc which ensures that tx is "in-flight" (prepped
908 * and submitted). Walking the parent chain is only meant to cover for DMA
909 * drivers that do not implement the DMA_INTERRUPT capability and may race with
910 * the driver's descriptor cleanup routine.
913 dma_wait_for_async_tx(struct dma_async_tx_descriptor
*tx
)
915 enum dma_status status
;
916 struct dma_async_tx_descriptor
*iter
;
917 struct dma_async_tx_descriptor
*parent
;
922 WARN_ONCE(tx
->parent
, "%s: speculatively walking dependency chain for"
923 " %s\n", __func__
, dma_chan_name(tx
->chan
));
925 /* poll through the dependency chain, return when tx is complete */
929 /* find the root of the unsubmitted dependency chain */
931 parent
= iter
->parent
;
938 /* there is a small window for ->parent == NULL and
941 while (iter
->cookie
== -EBUSY
)
944 status
= dma_sync_wait(iter
->chan
, iter
->cookie
);
945 } while (status
== DMA_IN_PROGRESS
|| (iter
!= tx
));
949 EXPORT_SYMBOL_GPL(dma_wait_for_async_tx
);
951 /* dma_run_dependencies - helper routine for dma drivers to process
952 * (start) dependent operations on their target channel
953 * @tx: transaction with dependencies
955 void dma_run_dependencies(struct dma_async_tx_descriptor
*tx
)
957 struct dma_async_tx_descriptor
*dep
= tx
->next
;
958 struct dma_async_tx_descriptor
*dep_next
;
959 struct dma_chan
*chan
;
966 /* keep submitting up until a channel switch is detected
967 * in that case we will be called again as a result of
968 * processing the interrupt from async_tx_channel_switch
970 for (; dep
; dep
= dep_next
) {
971 spin_lock_bh(&dep
->lock
);
973 dep_next
= dep
->next
;
974 if (dep_next
&& dep_next
->chan
== chan
)
975 dep
->next
= NULL
; /* ->next will be submitted */
977 dep_next
= NULL
; /* submit current dep and terminate */
978 spin_unlock_bh(&dep
->lock
);
983 chan
->device
->device_issue_pending(chan
);
985 EXPORT_SYMBOL_GPL(dma_run_dependencies
);
987 static int __init
dma_bus_init(void)
990 mutex_init(&dma_list_mutex
);
991 return class_register(&dma_devclass
);
993 arch_initcall(dma_bus_init
);