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/acpi.h>
66 #include <linux/acpi_dma.h>
67 #include <linux/of_dma.h>
68 #include <linux/mempool.h>
70 static DEFINE_MUTEX(dma_list_mutex
);
71 static DEFINE_IDR(dma_idr
);
72 static LIST_HEAD(dma_device_list
);
73 static long dmaengine_ref_count
;
75 /* --- sysfs implementation --- */
78 * dev_to_dma_chan - convert a device pointer to the its sysfs container object
81 * Must be called under dma_list_mutex
83 static struct dma_chan
*dev_to_dma_chan(struct device
*dev
)
85 struct dma_chan_dev
*chan_dev
;
87 chan_dev
= container_of(dev
, typeof(*chan_dev
), device
);
88 return chan_dev
->chan
;
91 static ssize_t
memcpy_count_show(struct device
*dev
,
92 struct device_attribute
*attr
, char *buf
)
94 struct dma_chan
*chan
;
95 unsigned long count
= 0;
99 mutex_lock(&dma_list_mutex
);
100 chan
= dev_to_dma_chan(dev
);
102 for_each_possible_cpu(i
)
103 count
+= per_cpu_ptr(chan
->local
, i
)->memcpy_count
;
104 err
= sprintf(buf
, "%lu\n", count
);
107 mutex_unlock(&dma_list_mutex
);
111 static DEVICE_ATTR_RO(memcpy_count
);
113 static ssize_t
bytes_transferred_show(struct device
*dev
,
114 struct device_attribute
*attr
, char *buf
)
116 struct dma_chan
*chan
;
117 unsigned long count
= 0;
121 mutex_lock(&dma_list_mutex
);
122 chan
= dev_to_dma_chan(dev
);
124 for_each_possible_cpu(i
)
125 count
+= per_cpu_ptr(chan
->local
, i
)->bytes_transferred
;
126 err
= sprintf(buf
, "%lu\n", count
);
129 mutex_unlock(&dma_list_mutex
);
133 static DEVICE_ATTR_RO(bytes_transferred
);
135 static ssize_t
in_use_show(struct device
*dev
, struct device_attribute
*attr
,
138 struct dma_chan
*chan
;
141 mutex_lock(&dma_list_mutex
);
142 chan
= dev_to_dma_chan(dev
);
144 err
= sprintf(buf
, "%d\n", chan
->client_count
);
147 mutex_unlock(&dma_list_mutex
);
151 static DEVICE_ATTR_RO(in_use
);
153 static struct attribute
*dma_dev_attrs
[] = {
154 &dev_attr_memcpy_count
.attr
,
155 &dev_attr_bytes_transferred
.attr
,
156 &dev_attr_in_use
.attr
,
159 ATTRIBUTE_GROUPS(dma_dev
);
161 static void chan_dev_release(struct device
*dev
)
163 struct dma_chan_dev
*chan_dev
;
165 chan_dev
= container_of(dev
, typeof(*chan_dev
), device
);
166 if (atomic_dec_and_test(chan_dev
->idr_ref
)) {
167 mutex_lock(&dma_list_mutex
);
168 idr_remove(&dma_idr
, chan_dev
->dev_id
);
169 mutex_unlock(&dma_list_mutex
);
170 kfree(chan_dev
->idr_ref
);
175 static struct class dma_devclass
= {
177 .dev_groups
= dma_dev_groups
,
178 .dev_release
= chan_dev_release
,
181 /* --- client and device registration --- */
183 #define dma_device_satisfies_mask(device, mask) \
184 __dma_device_satisfies_mask((device), &(mask))
186 __dma_device_satisfies_mask(struct dma_device
*device
,
187 const dma_cap_mask_t
*want
)
191 bitmap_and(has
.bits
, want
->bits
, device
->cap_mask
.bits
,
193 return bitmap_equal(want
->bits
, has
.bits
, DMA_TX_TYPE_END
);
196 static struct module
*dma_chan_to_owner(struct dma_chan
*chan
)
198 return chan
->device
->dev
->driver
->owner
;
202 * balance_ref_count - catch up the channel reference count
203 * @chan - channel to balance ->client_count versus dmaengine_ref_count
205 * balance_ref_count must be called under dma_list_mutex
207 static void balance_ref_count(struct dma_chan
*chan
)
209 struct module
*owner
= dma_chan_to_owner(chan
);
211 while (chan
->client_count
< dmaengine_ref_count
) {
213 chan
->client_count
++;
218 * dma_chan_get - try to grab a dma channel's parent driver module
219 * @chan - channel to grab
221 * Must be called under dma_list_mutex
223 static int dma_chan_get(struct dma_chan
*chan
)
226 struct module
*owner
= dma_chan_to_owner(chan
);
228 if (chan
->client_count
) {
231 } else if (try_module_get(owner
))
235 chan
->client_count
++;
237 /* allocate upon first client reference */
238 if (chan
->client_count
== 1 && err
== 0) {
239 int desc_cnt
= chan
->device
->device_alloc_chan_resources(chan
);
243 chan
->client_count
= 0;
245 } else if (!dma_has_cap(DMA_PRIVATE
, chan
->device
->cap_mask
))
246 balance_ref_count(chan
);
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 if (!chan
->client_count
)
261 return; /* this channel failed alloc_chan_resources */
262 chan
->client_count
--;
263 module_put(dma_chan_to_owner(chan
));
264 if (chan
->client_count
== 0)
265 chan
->device
->device_free_chan_resources(chan
);
268 enum dma_status
dma_sync_wait(struct dma_chan
*chan
, dma_cookie_t cookie
)
270 enum dma_status status
;
271 unsigned long dma_sync_wait_timeout
= jiffies
+ msecs_to_jiffies(5000);
273 dma_async_issue_pending(chan
);
275 status
= dma_async_is_tx_complete(chan
, cookie
, NULL
, NULL
);
276 if (time_after_eq(jiffies
, dma_sync_wait_timeout
)) {
277 pr_err("%s: timeout!\n", __func__
);
280 if (status
!= DMA_IN_PROGRESS
)
287 EXPORT_SYMBOL(dma_sync_wait
);
290 * dma_cap_mask_all - enable iteration over all operation types
292 static dma_cap_mask_t dma_cap_mask_all
;
295 * dma_chan_tbl_ent - tracks channel allocations per core/operation
296 * @chan - associated channel for this entry
298 struct dma_chan_tbl_ent
{
299 struct dma_chan
*chan
;
303 * channel_table - percpu lookup table for memory-to-memory offload providers
305 static struct dma_chan_tbl_ent __percpu
*channel_table
[DMA_TX_TYPE_END
];
307 static int __init
dma_channel_table_init(void)
309 enum dma_transaction_type cap
;
312 bitmap_fill(dma_cap_mask_all
.bits
, DMA_TX_TYPE_END
);
314 /* 'interrupt', 'private', and 'slave' are channel capabilities,
315 * but are not associated with an operation so they do not need
316 * an entry in the channel_table
318 clear_bit(DMA_INTERRUPT
, dma_cap_mask_all
.bits
);
319 clear_bit(DMA_PRIVATE
, dma_cap_mask_all
.bits
);
320 clear_bit(DMA_SLAVE
, dma_cap_mask_all
.bits
);
322 for_each_dma_cap_mask(cap
, dma_cap_mask_all
) {
323 channel_table
[cap
] = alloc_percpu(struct dma_chan_tbl_ent
);
324 if (!channel_table
[cap
]) {
331 pr_err("initialization failure\n");
332 for_each_dma_cap_mask(cap
, dma_cap_mask_all
)
333 if (channel_table
[cap
])
334 free_percpu(channel_table
[cap
]);
339 arch_initcall(dma_channel_table_init
);
342 * dma_find_channel - find a channel to carry out the operation
343 * @tx_type: transaction type
345 struct dma_chan
*dma_find_channel(enum dma_transaction_type tx_type
)
347 return this_cpu_read(channel_table
[tx_type
]->chan
);
349 EXPORT_SYMBOL(dma_find_channel
);
352 * net_dma_find_channel - find a channel for net_dma
353 * net_dma has alignment requirements
355 struct dma_chan
*net_dma_find_channel(void)
357 struct dma_chan
*chan
= dma_find_channel(DMA_MEMCPY
);
358 if (chan
&& !is_dma_copy_aligned(chan
->device
, 1, 1, 1))
363 EXPORT_SYMBOL(net_dma_find_channel
);
366 * dma_issue_pending_all - flush all pending operations across all channels
368 void dma_issue_pending_all(void)
370 struct dma_device
*device
;
371 struct dma_chan
*chan
;
374 list_for_each_entry_rcu(device
, &dma_device_list
, global_node
) {
375 if (dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
377 list_for_each_entry(chan
, &device
->channels
, device_node
)
378 if (chan
->client_count
)
379 device
->device_issue_pending(chan
);
383 EXPORT_SYMBOL(dma_issue_pending_all
);
386 * dma_chan_is_local - returns true if the channel is in the same numa-node as the cpu
388 static bool dma_chan_is_local(struct dma_chan
*chan
, int cpu
)
390 int node
= dev_to_node(chan
->device
->dev
);
391 return node
== -1 || cpumask_test_cpu(cpu
, cpumask_of_node(node
));
395 * min_chan - returns the channel with min count and in the same numa-node as the cpu
396 * @cap: capability to match
397 * @cpu: cpu index which the channel should be close to
399 * If some channels are close to the given cpu, the one with the lowest
400 * reference count is returned. Otherwise, cpu is ignored and only the
401 * reference count is taken into account.
402 * Must be called under dma_list_mutex.
404 static struct dma_chan
*min_chan(enum dma_transaction_type cap
, int cpu
)
406 struct dma_device
*device
;
407 struct dma_chan
*chan
;
408 struct dma_chan
*min
= NULL
;
409 struct dma_chan
*localmin
= NULL
;
411 list_for_each_entry(device
, &dma_device_list
, global_node
) {
412 if (!dma_has_cap(cap
, device
->cap_mask
) ||
413 dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
415 list_for_each_entry(chan
, &device
->channels
, device_node
) {
416 if (!chan
->client_count
)
418 if (!min
|| chan
->table_count
< min
->table_count
)
421 if (dma_chan_is_local(chan
, cpu
))
423 chan
->table_count
< localmin
->table_count
)
428 chan
= localmin
? localmin
: min
;
437 * dma_channel_rebalance - redistribute the available channels
439 * Optimize for cpu isolation (each cpu gets a dedicated channel for an
440 * operation type) in the SMP case, and operation isolation (avoid
441 * multi-tasking channels) in the non-SMP case. Must be called under
444 static void dma_channel_rebalance(void)
446 struct dma_chan
*chan
;
447 struct dma_device
*device
;
451 /* undo the last distribution */
452 for_each_dma_cap_mask(cap
, dma_cap_mask_all
)
453 for_each_possible_cpu(cpu
)
454 per_cpu_ptr(channel_table
[cap
], cpu
)->chan
= NULL
;
456 list_for_each_entry(device
, &dma_device_list
, global_node
) {
457 if (dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
459 list_for_each_entry(chan
, &device
->channels
, device_node
)
460 chan
->table_count
= 0;
463 /* don't populate the channel_table if no clients are available */
464 if (!dmaengine_ref_count
)
467 /* redistribute available channels */
468 for_each_dma_cap_mask(cap
, dma_cap_mask_all
)
469 for_each_online_cpu(cpu
) {
470 chan
= min_chan(cap
, cpu
);
471 per_cpu_ptr(channel_table
[cap
], cpu
)->chan
= chan
;
475 static struct dma_chan
*private_candidate(const dma_cap_mask_t
*mask
,
476 struct dma_device
*dev
,
477 dma_filter_fn fn
, void *fn_param
)
479 struct dma_chan
*chan
;
481 if (!__dma_device_satisfies_mask(dev
, mask
)) {
482 pr_debug("%s: wrong capabilities\n", __func__
);
485 /* devices with multiple channels need special handling as we need to
486 * ensure that all channels are either private or public.
488 if (dev
->chancnt
> 1 && !dma_has_cap(DMA_PRIVATE
, dev
->cap_mask
))
489 list_for_each_entry(chan
, &dev
->channels
, device_node
) {
490 /* some channels are already publicly allocated */
491 if (chan
->client_count
)
495 list_for_each_entry(chan
, &dev
->channels
, device_node
) {
496 if (chan
->client_count
) {
497 pr_debug("%s: %s busy\n",
498 __func__
, dma_chan_name(chan
));
501 if (fn
&& !fn(chan
, fn_param
)) {
502 pr_debug("%s: %s filter said false\n",
503 __func__
, dma_chan_name(chan
));
513 * dma_request_slave_channel - try to get specific channel exclusively
514 * @chan: target channel
516 struct dma_chan
*dma_get_slave_channel(struct dma_chan
*chan
)
520 /* lock against __dma_request_channel */
521 mutex_lock(&dma_list_mutex
);
523 if (chan
->client_count
== 0) {
524 err
= dma_chan_get(chan
);
526 pr_debug("%s: failed to get %s: (%d)\n",
527 __func__
, dma_chan_name(chan
), err
);
531 mutex_unlock(&dma_list_mutex
);
536 EXPORT_SYMBOL_GPL(dma_get_slave_channel
);
539 * __dma_request_channel - try to allocate an exclusive channel
540 * @mask: capabilities that the channel must satisfy
541 * @fn: optional callback to disposition available channels
542 * @fn_param: opaque parameter to pass to dma_filter_fn
544 * Returns pointer to appropriate DMA channel on success or NULL.
546 struct dma_chan
*__dma_request_channel(const dma_cap_mask_t
*mask
,
547 dma_filter_fn fn
, void *fn_param
)
549 struct dma_device
*device
, *_d
;
550 struct dma_chan
*chan
= NULL
;
554 mutex_lock(&dma_list_mutex
);
555 list_for_each_entry_safe(device
, _d
, &dma_device_list
, global_node
) {
556 chan
= private_candidate(mask
, device
, fn
, fn_param
);
558 /* Found a suitable channel, try to grab, prep, and
559 * return it. We first set DMA_PRIVATE to disable
560 * balance_ref_count as this channel will not be
561 * published in the general-purpose allocator
563 dma_cap_set(DMA_PRIVATE
, device
->cap_mask
);
564 device
->privatecnt
++;
565 err
= dma_chan_get(chan
);
567 if (err
== -ENODEV
) {
568 pr_debug("%s: %s module removed\n",
569 __func__
, dma_chan_name(chan
));
570 list_del_rcu(&device
->global_node
);
572 pr_debug("%s: failed to get %s: (%d)\n",
573 __func__
, dma_chan_name(chan
), err
);
576 if (--device
->privatecnt
== 0)
577 dma_cap_clear(DMA_PRIVATE
, device
->cap_mask
);
581 mutex_unlock(&dma_list_mutex
);
583 pr_debug("%s: %s (%s)\n",
585 chan
? "success" : "fail",
586 chan
? dma_chan_name(chan
) : NULL
);
590 EXPORT_SYMBOL_GPL(__dma_request_channel
);
593 * dma_request_slave_channel - try to allocate an exclusive slave channel
594 * @dev: pointer to client device structure
595 * @name: slave channel name
597 * Returns pointer to appropriate DMA channel on success or an error pointer.
599 struct dma_chan
*dma_request_slave_channel_reason(struct device
*dev
,
602 struct dma_chan
*chan
;
604 /* If device-tree is present get slave info from here */
606 return of_dma_request_slave_channel(dev
->of_node
, name
);
608 /* If device was enumerated by ACPI get slave info from here */
609 if (ACPI_HANDLE(dev
)) {
610 chan
= acpi_dma_request_slave_chan_by_name(dev
, name
);
615 return ERR_PTR(-ENODEV
);
617 EXPORT_SYMBOL_GPL(dma_request_slave_channel_reason
);
620 * dma_request_slave_channel - try to allocate an exclusive slave channel
621 * @dev: pointer to client device structure
622 * @name: slave channel name
624 * Returns pointer to appropriate DMA channel on success or NULL.
626 struct dma_chan
*dma_request_slave_channel(struct device
*dev
,
629 struct dma_chan
*ch
= dma_request_slave_channel_reason(dev
, name
);
634 EXPORT_SYMBOL_GPL(dma_request_slave_channel
);
636 void dma_release_channel(struct dma_chan
*chan
)
638 mutex_lock(&dma_list_mutex
);
639 WARN_ONCE(chan
->client_count
!= 1,
640 "chan reference count %d != 1\n", chan
->client_count
);
642 /* drop PRIVATE cap enabled by __dma_request_channel() */
643 if (--chan
->device
->privatecnt
== 0)
644 dma_cap_clear(DMA_PRIVATE
, chan
->device
->cap_mask
);
645 mutex_unlock(&dma_list_mutex
);
647 EXPORT_SYMBOL_GPL(dma_release_channel
);
650 * dmaengine_get - register interest in dma_channels
652 void dmaengine_get(void)
654 struct dma_device
*device
, *_d
;
655 struct dma_chan
*chan
;
658 mutex_lock(&dma_list_mutex
);
659 dmaengine_ref_count
++;
661 /* try to grab channels */
662 list_for_each_entry_safe(device
, _d
, &dma_device_list
, global_node
) {
663 if (dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
665 list_for_each_entry(chan
, &device
->channels
, device_node
) {
666 err
= dma_chan_get(chan
);
667 if (err
== -ENODEV
) {
668 /* module removed before we could use it */
669 list_del_rcu(&device
->global_node
);
672 pr_debug("%s: failed to get %s: (%d)\n",
673 __func__
, dma_chan_name(chan
), err
);
677 /* if this is the first reference and there were channels
678 * waiting we need to rebalance to get those channels
679 * incorporated into the channel table
681 if (dmaengine_ref_count
== 1)
682 dma_channel_rebalance();
683 mutex_unlock(&dma_list_mutex
);
685 EXPORT_SYMBOL(dmaengine_get
);
688 * dmaengine_put - let dma drivers be removed when ref_count == 0
690 void dmaengine_put(void)
692 struct dma_device
*device
;
693 struct dma_chan
*chan
;
695 mutex_lock(&dma_list_mutex
);
696 dmaengine_ref_count
--;
697 BUG_ON(dmaengine_ref_count
< 0);
698 /* drop channel references */
699 list_for_each_entry(device
, &dma_device_list
, global_node
) {
700 if (dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
702 list_for_each_entry(chan
, &device
->channels
, device_node
)
705 mutex_unlock(&dma_list_mutex
);
707 EXPORT_SYMBOL(dmaengine_put
);
709 static bool device_has_all_tx_types(struct dma_device
*device
)
711 /* A device that satisfies this test has channels that will never cause
712 * an async_tx channel switch event as all possible operation types can
715 #ifdef CONFIG_ASYNC_TX_DMA
716 if (!dma_has_cap(DMA_INTERRUPT
, device
->cap_mask
))
720 #if defined(CONFIG_ASYNC_MEMCPY) || defined(CONFIG_ASYNC_MEMCPY_MODULE)
721 if (!dma_has_cap(DMA_MEMCPY
, device
->cap_mask
))
725 #if defined(CONFIG_ASYNC_XOR) || defined(CONFIG_ASYNC_XOR_MODULE)
726 if (!dma_has_cap(DMA_XOR
, device
->cap_mask
))
729 #ifndef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
730 if (!dma_has_cap(DMA_XOR_VAL
, device
->cap_mask
))
735 #if defined(CONFIG_ASYNC_PQ) || defined(CONFIG_ASYNC_PQ_MODULE)
736 if (!dma_has_cap(DMA_PQ
, device
->cap_mask
))
739 #ifndef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
740 if (!dma_has_cap(DMA_PQ_VAL
, device
->cap_mask
))
748 static int get_dma_id(struct dma_device
*device
)
752 mutex_lock(&dma_list_mutex
);
754 rc
= idr_alloc(&dma_idr
, NULL
, 0, 0, GFP_KERNEL
);
758 mutex_unlock(&dma_list_mutex
);
759 return rc
< 0 ? rc
: 0;
763 * dma_async_device_register - registers DMA devices found
764 * @device: &dma_device
766 int dma_async_device_register(struct dma_device
*device
)
769 struct dma_chan
* chan
;
775 /* validate device routines */
776 BUG_ON(dma_has_cap(DMA_MEMCPY
, device
->cap_mask
) &&
777 !device
->device_prep_dma_memcpy
);
778 BUG_ON(dma_has_cap(DMA_XOR
, device
->cap_mask
) &&
779 !device
->device_prep_dma_xor
);
780 BUG_ON(dma_has_cap(DMA_XOR_VAL
, device
->cap_mask
) &&
781 !device
->device_prep_dma_xor_val
);
782 BUG_ON(dma_has_cap(DMA_PQ
, device
->cap_mask
) &&
783 !device
->device_prep_dma_pq
);
784 BUG_ON(dma_has_cap(DMA_PQ_VAL
, device
->cap_mask
) &&
785 !device
->device_prep_dma_pq_val
);
786 BUG_ON(dma_has_cap(DMA_INTERRUPT
, device
->cap_mask
) &&
787 !device
->device_prep_dma_interrupt
);
788 BUG_ON(dma_has_cap(DMA_SG
, device
->cap_mask
) &&
789 !device
->device_prep_dma_sg
);
790 BUG_ON(dma_has_cap(DMA_CYCLIC
, device
->cap_mask
) &&
791 !device
->device_prep_dma_cyclic
);
792 BUG_ON(dma_has_cap(DMA_SLAVE
, device
->cap_mask
) &&
793 !device
->device_control
);
794 BUG_ON(dma_has_cap(DMA_INTERLEAVE
, device
->cap_mask
) &&
795 !device
->device_prep_interleaved_dma
);
797 BUG_ON(!device
->device_alloc_chan_resources
);
798 BUG_ON(!device
->device_free_chan_resources
);
799 BUG_ON(!device
->device_tx_status
);
800 BUG_ON(!device
->device_issue_pending
);
801 BUG_ON(!device
->dev
);
803 /* note: this only matters in the
804 * CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH=n case
806 if (device_has_all_tx_types(device
))
807 dma_cap_set(DMA_ASYNC_TX
, device
->cap_mask
);
809 idr_ref
= kmalloc(sizeof(*idr_ref
), GFP_KERNEL
);
812 rc
= get_dma_id(device
);
818 atomic_set(idr_ref
, 0);
820 /* represent channels in sysfs. Probably want devs too */
821 list_for_each_entry(chan
, &device
->channels
, device_node
) {
823 chan
->local
= alloc_percpu(typeof(*chan
->local
));
824 if (chan
->local
== NULL
)
826 chan
->dev
= kzalloc(sizeof(*chan
->dev
), GFP_KERNEL
);
827 if (chan
->dev
== NULL
) {
828 free_percpu(chan
->local
);
833 chan
->chan_id
= chancnt
++;
834 chan
->dev
->device
.class = &dma_devclass
;
835 chan
->dev
->device
.parent
= device
->dev
;
836 chan
->dev
->chan
= chan
;
837 chan
->dev
->idr_ref
= idr_ref
;
838 chan
->dev
->dev_id
= device
->dev_id
;
840 dev_set_name(&chan
->dev
->device
, "dma%dchan%d",
841 device
->dev_id
, chan
->chan_id
);
843 rc
= device_register(&chan
->dev
->device
);
845 free_percpu(chan
->local
);
851 chan
->client_count
= 0;
853 device
->chancnt
= chancnt
;
855 mutex_lock(&dma_list_mutex
);
856 /* take references on public channels */
857 if (dmaengine_ref_count
&& !dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
858 list_for_each_entry(chan
, &device
->channels
, device_node
) {
859 /* if clients are already waiting for channels we need
860 * to take references on their behalf
862 if (dma_chan_get(chan
) == -ENODEV
) {
863 /* note we can only get here for the first
864 * channel as the remaining channels are
865 * guaranteed to get a reference
868 mutex_unlock(&dma_list_mutex
);
872 list_add_tail_rcu(&device
->global_node
, &dma_device_list
);
873 if (dma_has_cap(DMA_PRIVATE
, device
->cap_mask
))
874 device
->privatecnt
++; /* Always private */
875 dma_channel_rebalance();
876 mutex_unlock(&dma_list_mutex
);
881 /* if we never registered a channel just release the idr */
882 if (atomic_read(idr_ref
) == 0) {
883 mutex_lock(&dma_list_mutex
);
884 idr_remove(&dma_idr
, device
->dev_id
);
885 mutex_unlock(&dma_list_mutex
);
890 list_for_each_entry(chan
, &device
->channels
, device_node
) {
891 if (chan
->local
== NULL
)
893 mutex_lock(&dma_list_mutex
);
894 chan
->dev
->chan
= NULL
;
895 mutex_unlock(&dma_list_mutex
);
896 device_unregister(&chan
->dev
->device
);
897 free_percpu(chan
->local
);
901 EXPORT_SYMBOL(dma_async_device_register
);
904 * dma_async_device_unregister - unregister a DMA device
905 * @device: &dma_device
907 * This routine is called by dma driver exit routines, dmaengine holds module
908 * references to prevent it being called while channels are in use.
910 void dma_async_device_unregister(struct dma_device
*device
)
912 struct dma_chan
*chan
;
914 mutex_lock(&dma_list_mutex
);
915 list_del_rcu(&device
->global_node
);
916 dma_channel_rebalance();
917 mutex_unlock(&dma_list_mutex
);
919 list_for_each_entry(chan
, &device
->channels
, device_node
) {
920 WARN_ONCE(chan
->client_count
,
921 "%s called while %d clients hold a reference\n",
922 __func__
, chan
->client_count
);
923 mutex_lock(&dma_list_mutex
);
924 chan
->dev
->chan
= NULL
;
925 mutex_unlock(&dma_list_mutex
);
926 device_unregister(&chan
->dev
->device
);
927 free_percpu(chan
->local
);
930 EXPORT_SYMBOL(dma_async_device_unregister
);
932 struct dmaengine_unmap_pool
{
933 struct kmem_cache
*cache
;
939 #define __UNMAP_POOL(x) { .size = x, .name = "dmaengine-unmap-" __stringify(x) }
940 static struct dmaengine_unmap_pool unmap_pool
[] = {
942 #if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
949 static struct dmaengine_unmap_pool
*__get_unmap_pool(int nr
)
951 int order
= get_count_order(nr
);
955 return &unmap_pool
[0];
957 return &unmap_pool
[1];
959 return &unmap_pool
[2];
961 return &unmap_pool
[3];
968 static void dmaengine_unmap(struct kref
*kref
)
970 struct dmaengine_unmap_data
*unmap
= container_of(kref
, typeof(*unmap
), kref
);
971 struct device
*dev
= unmap
->dev
;
975 for (i
= 0; i
< cnt
; i
++)
976 dma_unmap_page(dev
, unmap
->addr
[i
], unmap
->len
,
978 cnt
+= unmap
->from_cnt
;
980 dma_unmap_page(dev
, unmap
->addr
[i
], unmap
->len
,
982 cnt
+= unmap
->bidi_cnt
;
983 for (; i
< cnt
; i
++) {
984 if (unmap
->addr
[i
] == 0)
986 dma_unmap_page(dev
, unmap
->addr
[i
], unmap
->len
,
989 mempool_free(unmap
, __get_unmap_pool(cnt
)->pool
);
992 void dmaengine_unmap_put(struct dmaengine_unmap_data
*unmap
)
995 kref_put(&unmap
->kref
, dmaengine_unmap
);
997 EXPORT_SYMBOL_GPL(dmaengine_unmap_put
);
999 static void dmaengine_destroy_unmap_pool(void)
1003 for (i
= 0; i
< ARRAY_SIZE(unmap_pool
); i
++) {
1004 struct dmaengine_unmap_pool
*p
= &unmap_pool
[i
];
1007 mempool_destroy(p
->pool
);
1010 kmem_cache_destroy(p
->cache
);
1015 static int __init
dmaengine_init_unmap_pool(void)
1019 for (i
= 0; i
< ARRAY_SIZE(unmap_pool
); i
++) {
1020 struct dmaengine_unmap_pool
*p
= &unmap_pool
[i
];
1023 size
= sizeof(struct dmaengine_unmap_data
) +
1024 sizeof(dma_addr_t
) * p
->size
;
1026 p
->cache
= kmem_cache_create(p
->name
, size
, 0,
1027 SLAB_HWCACHE_ALIGN
, NULL
);
1030 p
->pool
= mempool_create_slab_pool(1, p
->cache
);
1035 if (i
== ARRAY_SIZE(unmap_pool
))
1038 dmaengine_destroy_unmap_pool();
1042 struct dmaengine_unmap_data
*
1043 dmaengine_get_unmap_data(struct device
*dev
, int nr
, gfp_t flags
)
1045 struct dmaengine_unmap_data
*unmap
;
1047 unmap
= mempool_alloc(__get_unmap_pool(nr
)->pool
, flags
);
1051 memset(unmap
, 0, sizeof(*unmap
));
1052 kref_init(&unmap
->kref
);
1057 EXPORT_SYMBOL(dmaengine_get_unmap_data
);
1060 * dma_async_memcpy_pg_to_pg - offloaded copy from page to page
1061 * @chan: DMA channel to offload copy to
1062 * @dest_pg: destination page
1063 * @dest_off: offset in page to copy to
1064 * @src_pg: source page
1065 * @src_off: offset in page to copy from
1068 * Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
1069 * address according to the DMA mapping API rules for streaming mappings.
1070 * Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
1071 * (kernel memory or locked user space pages).
1074 dma_async_memcpy_pg_to_pg(struct dma_chan
*chan
, struct page
*dest_pg
,
1075 unsigned int dest_off
, struct page
*src_pg
, unsigned int src_off
,
1078 struct dma_device
*dev
= chan
->device
;
1079 struct dma_async_tx_descriptor
*tx
;
1080 struct dmaengine_unmap_data
*unmap
;
1081 dma_cookie_t cookie
;
1082 unsigned long flags
;
1084 unmap
= dmaengine_get_unmap_data(dev
->dev
, 2, GFP_NOWAIT
);
1089 unmap
->from_cnt
= 1;
1090 unmap
->addr
[0] = dma_map_page(dev
->dev
, src_pg
, src_off
, len
,
1092 unmap
->addr
[1] = dma_map_page(dev
->dev
, dest_pg
, dest_off
, len
,
1095 flags
= DMA_CTRL_ACK
;
1096 tx
= dev
->device_prep_dma_memcpy(chan
, unmap
->addr
[1], unmap
->addr
[0],
1100 dmaengine_unmap_put(unmap
);
1104 dma_set_unmap(tx
, unmap
);
1105 cookie
= tx
->tx_submit(tx
);
1106 dmaengine_unmap_put(unmap
);
1109 __this_cpu_add(chan
->local
->bytes_transferred
, len
);
1110 __this_cpu_inc(chan
->local
->memcpy_count
);
1115 EXPORT_SYMBOL(dma_async_memcpy_pg_to_pg
);
1118 * dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
1119 * @chan: DMA channel to offload copy to
1120 * @dest: destination address (virtual)
1121 * @src: source address (virtual)
1124 * Both @dest and @src must be mappable to a bus address according to the
1125 * DMA mapping API rules for streaming mappings.
1126 * Both @dest and @src must stay memory resident (kernel memory or locked
1127 * user space pages).
1130 dma_async_memcpy_buf_to_buf(struct dma_chan
*chan
, void *dest
,
1131 void *src
, size_t len
)
1133 return dma_async_memcpy_pg_to_pg(chan
, virt_to_page(dest
),
1134 (unsigned long) dest
& ~PAGE_MASK
,
1136 (unsigned long) src
& ~PAGE_MASK
, len
);
1138 EXPORT_SYMBOL(dma_async_memcpy_buf_to_buf
);
1141 * dma_async_memcpy_buf_to_pg - offloaded copy from address to page
1142 * @chan: DMA channel to offload copy to
1143 * @page: destination page
1144 * @offset: offset in page to copy to
1145 * @kdata: source address (virtual)
1148 * Both @page/@offset and @kdata must be mappable to a bus address according
1149 * to the DMA mapping API rules for streaming mappings.
1150 * Both @page/@offset and @kdata must stay memory resident (kernel memory or
1151 * locked user space pages)
1154 dma_async_memcpy_buf_to_pg(struct dma_chan
*chan
, struct page
*page
,
1155 unsigned int offset
, void *kdata
, size_t len
)
1157 return dma_async_memcpy_pg_to_pg(chan
, page
, offset
,
1158 virt_to_page(kdata
),
1159 (unsigned long) kdata
& ~PAGE_MASK
, len
);
1161 EXPORT_SYMBOL(dma_async_memcpy_buf_to_pg
);
1163 void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor
*tx
,
1164 struct dma_chan
*chan
)
1167 #ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
1168 spin_lock_init(&tx
->lock
);
1171 EXPORT_SYMBOL(dma_async_tx_descriptor_init
);
1173 /* dma_wait_for_async_tx - spin wait for a transaction to complete
1174 * @tx: in-flight transaction to wait on
1177 dma_wait_for_async_tx(struct dma_async_tx_descriptor
*tx
)
1179 unsigned long dma_sync_wait_timeout
= jiffies
+ msecs_to_jiffies(5000);
1182 return DMA_COMPLETE
;
1184 while (tx
->cookie
== -EBUSY
) {
1185 if (time_after_eq(jiffies
, dma_sync_wait_timeout
)) {
1186 pr_err("%s timeout waiting for descriptor submission\n",
1192 return dma_sync_wait(tx
->chan
, tx
->cookie
);
1194 EXPORT_SYMBOL_GPL(dma_wait_for_async_tx
);
1196 /* dma_run_dependencies - helper routine for dma drivers to process
1197 * (start) dependent operations on their target channel
1198 * @tx: transaction with dependencies
1200 void dma_run_dependencies(struct dma_async_tx_descriptor
*tx
)
1202 struct dma_async_tx_descriptor
*dep
= txd_next(tx
);
1203 struct dma_async_tx_descriptor
*dep_next
;
1204 struct dma_chan
*chan
;
1209 /* we'll submit tx->next now, so clear the link */
1213 /* keep submitting up until a channel switch is detected
1214 * in that case we will be called again as a result of
1215 * processing the interrupt from async_tx_channel_switch
1217 for (; dep
; dep
= dep_next
) {
1219 txd_clear_parent(dep
);
1220 dep_next
= txd_next(dep
);
1221 if (dep_next
&& dep_next
->chan
== chan
)
1222 txd_clear_next(dep
); /* ->next will be submitted */
1224 dep_next
= NULL
; /* submit current dep and terminate */
1227 dep
->tx_submit(dep
);
1230 chan
->device
->device_issue_pending(chan
);
1232 EXPORT_SYMBOL_GPL(dma_run_dependencies
);
1234 static int __init
dma_bus_init(void)
1236 int err
= dmaengine_init_unmap_pool();
1240 return class_register(&dma_devclass
);
1242 arch_initcall(dma_bus_init
);