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1/*
2 * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
3 *
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)
7 * any later version.
8 *
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
12 * more details.
13 *
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.
17 *
18 * The full GNU General Public License is included in this distribution in the
19 * file called COPYING.
20 */
21
22/*
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
26 * this capability.
27 *
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,
30 * such as locking.
31 *
32 * LOCKING:
33 *
34 * The subsystem keeps a global list of dma_device structs it is protected by a
35 * mutex, dma_list_mutex.
36 *
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.
41 *
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.
44 *
45 * See Documentation/dmaengine.txt for more details
46 */
47
48#include <linux/dma-mapping.h>
49#include <linux/init.h>
50#include <linux/module.h>
51#include <linux/mm.h>
52#include <linux/device.h>
53#include <linux/dmaengine.h>
54#include <linux/hardirq.h>
55#include <linux/spinlock.h>
56#include <linux/percpu.h>
57#include <linux/rcupdate.h>
58#include <linux/mutex.h>
59#include <linux/jiffies.h>
60#include <linux/rculist.h>
61#include <linux/idr.h>
62#include <linux/slab.h>
63
64static DEFINE_MUTEX(dma_list_mutex);
65static DEFINE_IDR(dma_idr);
66static LIST_HEAD(dma_device_list);
67static long dmaengine_ref_count;
68
69/* --- sysfs implementation --- */
70
71/**
72 * dev_to_dma_chan - convert a device pointer to the its sysfs container object
73 * @dev - device node
74 *
75 * Must be called under dma_list_mutex
76 */
77static struct dma_chan *dev_to_dma_chan(struct device *dev)
78{
79 struct dma_chan_dev *chan_dev;
80
81 chan_dev = container_of(dev, typeof(*chan_dev), device);
82 return chan_dev->chan;
83}
84
85static ssize_t show_memcpy_count(struct device *dev, struct device_attribute *attr, char *buf)
86{
87 struct dma_chan *chan;
88 unsigned long count = 0;
89 int i;
90 int err;
91
92 mutex_lock(&dma_list_mutex);
93 chan = dev_to_dma_chan(dev);
94 if (chan) {
95 for_each_possible_cpu(i)
96 count += per_cpu_ptr(chan->local, i)->memcpy_count;
97 err = sprintf(buf, "%lu\n", count);
98 } else
99 err = -ENODEV;
100 mutex_unlock(&dma_list_mutex);
101
102 return err;
103}
104
105static ssize_t show_bytes_transferred(struct device *dev, struct device_attribute *attr,
106 char *buf)
107{
108 struct dma_chan *chan;
109 unsigned long count = 0;
110 int i;
111 int err;
112
113 mutex_lock(&dma_list_mutex);
114 chan = dev_to_dma_chan(dev);
115 if (chan) {
116 for_each_possible_cpu(i)
117 count += per_cpu_ptr(chan->local, i)->bytes_transferred;
118 err = sprintf(buf, "%lu\n", count);
119 } else
120 err = -ENODEV;
121 mutex_unlock(&dma_list_mutex);
122
123 return err;
124}
125
126static ssize_t show_in_use(struct device *dev, struct device_attribute *attr, char *buf)
127{
128 struct dma_chan *chan;
129 int err;
130
131 mutex_lock(&dma_list_mutex);
132 chan = dev_to_dma_chan(dev);
133 if (chan)
134 err = sprintf(buf, "%d\n", chan->client_count);
135 else
136 err = -ENODEV;
137 mutex_unlock(&dma_list_mutex);
138
139 return err;
140}
141
142static struct device_attribute dma_attrs[] = {
143 __ATTR(memcpy_count, S_IRUGO, show_memcpy_count, NULL),
144 __ATTR(bytes_transferred, S_IRUGO, show_bytes_transferred, NULL),
145 __ATTR(in_use, S_IRUGO, show_in_use, NULL),
146 __ATTR_NULL
147};
148
149static void chan_dev_release(struct device *dev)
150{
151 struct dma_chan_dev *chan_dev;
152
153 chan_dev = container_of(dev, typeof(*chan_dev), device);
154 if (atomic_dec_and_test(chan_dev->idr_ref)) {
155 mutex_lock(&dma_list_mutex);
156 idr_remove(&dma_idr, chan_dev->dev_id);
157 mutex_unlock(&dma_list_mutex);
158 kfree(chan_dev->idr_ref);
159 }
160 kfree(chan_dev);
161}
162
163static struct class dma_devclass = {
164 .name = "dma",
165 .dev_attrs = dma_attrs,
166 .dev_release = chan_dev_release,
167};
168
169/* --- client and device registration --- */
170
171#define dma_device_satisfies_mask(device, mask) \
172 __dma_device_satisfies_mask((device), &(mask))
173static int
174__dma_device_satisfies_mask(struct dma_device *device, dma_cap_mask_t *want)
175{
176 dma_cap_mask_t has;
177
178 bitmap_and(has.bits, want->bits, device->cap_mask.bits,
179 DMA_TX_TYPE_END);
180 return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END);
181}
182
183static struct module *dma_chan_to_owner(struct dma_chan *chan)
184{
185 return chan->device->dev->driver->owner;
186}
187
188/**
189 * balance_ref_count - catch up the channel reference count
190 * @chan - channel to balance ->client_count versus dmaengine_ref_count
191 *
192 * balance_ref_count must be called under dma_list_mutex
193 */
194static void balance_ref_count(struct dma_chan *chan)
195{
196 struct module *owner = dma_chan_to_owner(chan);
197
198 while (chan->client_count < dmaengine_ref_count) {
199 __module_get(owner);
200 chan->client_count++;
201 }
202}
203
204/**
205 * dma_chan_get - try to grab a dma channel's parent driver module
206 * @chan - channel to grab
207 *
208 * Must be called under dma_list_mutex
209 */
210static int dma_chan_get(struct dma_chan *chan)
211{
212 int err = -ENODEV;
213 struct module *owner = dma_chan_to_owner(chan);
214
215 if (chan->client_count) {
216 __module_get(owner);
217 err = 0;
218 } else if (try_module_get(owner))
219 err = 0;
220
221 if (err == 0)
222 chan->client_count++;
223
224 /* allocate upon first client reference */
225 if (chan->client_count == 1 && err == 0) {
226 int desc_cnt = chan->device->device_alloc_chan_resources(chan);
227
228 if (desc_cnt < 0) {
229 err = desc_cnt;
230 chan->client_count = 0;
231 module_put(owner);
232 } else if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
233 balance_ref_count(chan);
234 }
235
236 return err;
237}
238
239/**
240 * dma_chan_put - drop a reference to a dma channel's parent driver module
241 * @chan - channel to release
242 *
243 * Must be called under dma_list_mutex
244 */
245static void dma_chan_put(struct dma_chan *chan)
246{
247 if (!chan->client_count)
248 return; /* this channel failed alloc_chan_resources */
249 chan->client_count--;
250 module_put(dma_chan_to_owner(chan));
251 if (chan->client_count == 0)
252 chan->device->device_free_chan_resources(chan);
253}
254
255enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
256{
257 enum dma_status status;
258 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
259
260 dma_async_issue_pending(chan);
261 do {
262 status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
263 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
264 printk(KERN_ERR "dma_sync_wait_timeout!\n");
265 return DMA_ERROR;
266 }
267 } while (status == DMA_IN_PROGRESS);
268
269 return status;
270}
271EXPORT_SYMBOL(dma_sync_wait);
272
273/**
274 * dma_cap_mask_all - enable iteration over all operation types
275 */
276static dma_cap_mask_t dma_cap_mask_all;
277
278/**
279 * dma_chan_tbl_ent - tracks channel allocations per core/operation
280 * @chan - associated channel for this entry
281 */
282struct dma_chan_tbl_ent {
283 struct dma_chan *chan;
284};
285
286/**
287 * channel_table - percpu lookup table for memory-to-memory offload providers
288 */
289static struct dma_chan_tbl_ent __percpu *channel_table[DMA_TX_TYPE_END];
290
291static int __init dma_channel_table_init(void)
292{
293 enum dma_transaction_type cap;
294 int err = 0;
295
296 bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END);
297
298 /* 'interrupt', 'private', and 'slave' are channel capabilities,
299 * but are not associated with an operation so they do not need
300 * an entry in the channel_table
301 */
302 clear_bit(DMA_INTERRUPT, dma_cap_mask_all.bits);
303 clear_bit(DMA_PRIVATE, dma_cap_mask_all.bits);
304 clear_bit(DMA_SLAVE, dma_cap_mask_all.bits);
305
306 for_each_dma_cap_mask(cap, dma_cap_mask_all) {
307 channel_table[cap] = alloc_percpu(struct dma_chan_tbl_ent);
308 if (!channel_table[cap]) {
309 err = -ENOMEM;
310 break;
311 }
312 }
313
314 if (err) {
315 pr_err("dmaengine: initialization failure\n");
316 for_each_dma_cap_mask(cap, dma_cap_mask_all)
317 if (channel_table[cap])
318 free_percpu(channel_table[cap]);
319 }
320
321 return err;
322}
323arch_initcall(dma_channel_table_init);
324
325/**
326 * dma_find_channel - find a channel to carry out the operation
327 * @tx_type: transaction type
328 */
329struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
330{
331 return this_cpu_read(channel_table[tx_type]->chan);
332}
333EXPORT_SYMBOL(dma_find_channel);
334
335/**
336 * dma_issue_pending_all - flush all pending operations across all channels
337 */
338void dma_issue_pending_all(void)
339{
340 struct dma_device *device;
341 struct dma_chan *chan;
342
343 rcu_read_lock();
344 list_for_each_entry_rcu(device, &dma_device_list, global_node) {
345 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
346 continue;
347 list_for_each_entry(chan, &device->channels, device_node)
348 if (chan->client_count)
349 device->device_issue_pending(chan);
350 }
351 rcu_read_unlock();
352}
353EXPORT_SYMBOL(dma_issue_pending_all);
354
355/**
356 * nth_chan - returns the nth channel of the given capability
357 * @cap: capability to match
358 * @n: nth channel desired
359 *
360 * Defaults to returning the channel with the desired capability and the
361 * lowest reference count when 'n' cannot be satisfied. Must be called
362 * under dma_list_mutex.
363 */
364static struct dma_chan *nth_chan(enum dma_transaction_type cap, int n)
365{
366 struct dma_device *device;
367 struct dma_chan *chan;
368 struct dma_chan *ret = NULL;
369 struct dma_chan *min = NULL;
370
371 list_for_each_entry(device, &dma_device_list, global_node) {
372 if (!dma_has_cap(cap, device->cap_mask) ||
373 dma_has_cap(DMA_PRIVATE, device->cap_mask))
374 continue;
375 list_for_each_entry(chan, &device->channels, device_node) {
376 if (!chan->client_count)
377 continue;
378 if (!min)
379 min = chan;
380 else if (chan->table_count < min->table_count)
381 min = chan;
382
383 if (n-- == 0) {
384 ret = chan;
385 break; /* done */
386 }
387 }
388 if (ret)
389 break; /* done */
390 }
391
392 if (!ret)
393 ret = min;
394
395 if (ret)
396 ret->table_count++;
397
398 return ret;
399}
400
401/**
402 * dma_channel_rebalance - redistribute the available channels
403 *
404 * Optimize for cpu isolation (each cpu gets a dedicated channel for an
405 * operation type) in the SMP case, and operation isolation (avoid
406 * multi-tasking channels) in the non-SMP case. Must be called under
407 * dma_list_mutex.
408 */
409static void dma_channel_rebalance(void)
410{
411 struct dma_chan *chan;
412 struct dma_device *device;
413 int cpu;
414 int cap;
415 int n;
416
417 /* undo the last distribution */
418 for_each_dma_cap_mask(cap, dma_cap_mask_all)
419 for_each_possible_cpu(cpu)
420 per_cpu_ptr(channel_table[cap], cpu)->chan = NULL;
421
422 list_for_each_entry(device, &dma_device_list, global_node) {
423 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
424 continue;
425 list_for_each_entry(chan, &device->channels, device_node)
426 chan->table_count = 0;
427 }
428
429 /* don't populate the channel_table if no clients are available */
430 if (!dmaengine_ref_count)
431 return;
432
433 /* redistribute available channels */
434 n = 0;
435 for_each_dma_cap_mask(cap, dma_cap_mask_all)
436 for_each_online_cpu(cpu) {
437 if (num_possible_cpus() > 1)
438 chan = nth_chan(cap, n++);
439 else
440 chan = nth_chan(cap, -1);
441
442 per_cpu_ptr(channel_table[cap], cpu)->chan = chan;
443 }
444}
445
446static struct dma_chan *private_candidate(dma_cap_mask_t *mask, struct dma_device *dev,
447 dma_filter_fn fn, void *fn_param)
448{
449 struct dma_chan *chan;
450
451 if (!__dma_device_satisfies_mask(dev, mask)) {
452 pr_debug("%s: wrong capabilities\n", __func__);
453 return NULL;
454 }
455 /* devices with multiple channels need special handling as we need to
456 * ensure that all channels are either private or public.
457 */
458 if (dev->chancnt > 1 && !dma_has_cap(DMA_PRIVATE, dev->cap_mask))
459 list_for_each_entry(chan, &dev->channels, device_node) {
460 /* some channels are already publicly allocated */
461 if (chan->client_count)
462 return NULL;
463 }
464
465 list_for_each_entry(chan, &dev->channels, device_node) {
466 if (chan->client_count) {
467 pr_debug("%s: %s busy\n",
468 __func__, dma_chan_name(chan));
469 continue;
470 }
471 if (fn && !fn(chan, fn_param)) {
472 pr_debug("%s: %s filter said false\n",
473 __func__, dma_chan_name(chan));
474 continue;
475 }
476 return chan;
477 }
478
479 return NULL;
480}
481
482/**
483 * dma_request_channel - try to allocate an exclusive channel
484 * @mask: capabilities that the channel must satisfy
485 * @fn: optional callback to disposition available channels
486 * @fn_param: opaque parameter to pass to dma_filter_fn
487 */
488struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, void *fn_param)
489{
490 struct dma_device *device, *_d;
491 struct dma_chan *chan = NULL;
492 int err;
493
494 /* Find a channel */
495 mutex_lock(&dma_list_mutex);
496 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
497 chan = private_candidate(mask, device, fn, fn_param);
498 if (chan) {
499 /* Found a suitable channel, try to grab, prep, and
500 * return it. We first set DMA_PRIVATE to disable
501 * balance_ref_count as this channel will not be
502 * published in the general-purpose allocator
503 */
504 dma_cap_set(DMA_PRIVATE, device->cap_mask);
505 device->privatecnt++;
506 err = dma_chan_get(chan);
507
508 if (err == -ENODEV) {
509 pr_debug("%s: %s module removed\n", __func__,
510 dma_chan_name(chan));
511 list_del_rcu(&device->global_node);
512 } else if (err)
513 pr_debug("dmaengine: failed to get %s: (%d)\n",
514 dma_chan_name(chan), err);
515 else
516 break;
517 if (--device->privatecnt == 0)
518 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
519 chan = NULL;
520 }
521 }
522 mutex_unlock(&dma_list_mutex);
523
524 pr_debug("%s: %s (%s)\n", __func__, chan ? "success" : "fail",
525 chan ? dma_chan_name(chan) : NULL);
526
527 return chan;
528}
529EXPORT_SYMBOL_GPL(__dma_request_channel);
530
531void dma_release_channel(struct dma_chan *chan)
532{
533 mutex_lock(&dma_list_mutex);
534 WARN_ONCE(chan->client_count != 1,
535 "chan reference count %d != 1\n", chan->client_count);
536 dma_chan_put(chan);
537 /* drop PRIVATE cap enabled by __dma_request_channel() */
538 if (--chan->device->privatecnt == 0)
539 dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
540 mutex_unlock(&dma_list_mutex);
541}
542EXPORT_SYMBOL_GPL(dma_release_channel);
543
544/**
545 * dmaengine_get - register interest in dma_channels
546 */
547void dmaengine_get(void)
548{
549 struct dma_device *device, *_d;
550 struct dma_chan *chan;
551 int err;
552
553 mutex_lock(&dma_list_mutex);
554 dmaengine_ref_count++;
555
556 /* try to grab channels */
557 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
558 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
559 continue;
560 list_for_each_entry(chan, &device->channels, device_node) {
561 err = dma_chan_get(chan);
562 if (err == -ENODEV) {
563 /* module removed before we could use it */
564 list_del_rcu(&device->global_node);
565 break;
566 } else if (err)
567 pr_err("dmaengine: failed to get %s: (%d)\n",
568 dma_chan_name(chan), err);
569 }
570 }
571
572 /* if this is the first reference and there were channels
573 * waiting we need to rebalance to get those channels
574 * incorporated into the channel table
575 */
576 if (dmaengine_ref_count == 1)
577 dma_channel_rebalance();
578 mutex_unlock(&dma_list_mutex);
579}
580EXPORT_SYMBOL(dmaengine_get);
581
582/**
583 * dmaengine_put - let dma drivers be removed when ref_count == 0
584 */
585void dmaengine_put(void)
586{
587 struct dma_device *device;
588 struct dma_chan *chan;
589
590 mutex_lock(&dma_list_mutex);
591 dmaengine_ref_count--;
592 BUG_ON(dmaengine_ref_count < 0);
593 /* drop channel references */
594 list_for_each_entry(device, &dma_device_list, global_node) {
595 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
596 continue;
597 list_for_each_entry(chan, &device->channels, device_node)
598 dma_chan_put(chan);
599 }
600 mutex_unlock(&dma_list_mutex);
601}
602EXPORT_SYMBOL(dmaengine_put);
603
604static bool device_has_all_tx_types(struct dma_device *device)
605{
606 /* A device that satisfies this test has channels that will never cause
607 * an async_tx channel switch event as all possible operation types can
608 * be handled.
609 */
610 #ifdef CONFIG_ASYNC_TX_DMA
611 if (!dma_has_cap(DMA_INTERRUPT, device->cap_mask))
612 return false;
613 #endif
614
615 #if defined(CONFIG_ASYNC_MEMCPY) || defined(CONFIG_ASYNC_MEMCPY_MODULE)
616 if (!dma_has_cap(DMA_MEMCPY, device->cap_mask))
617 return false;
618 #endif
619
620 #if defined(CONFIG_ASYNC_MEMSET) || defined(CONFIG_ASYNC_MEMSET_MODULE)
621 if (!dma_has_cap(DMA_MEMSET, device->cap_mask))
622 return false;
623 #endif
624
625 #if defined(CONFIG_ASYNC_XOR) || defined(CONFIG_ASYNC_XOR_MODULE)
626 if (!dma_has_cap(DMA_XOR, device->cap_mask))
627 return false;
628
629 #ifndef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
630 if (!dma_has_cap(DMA_XOR_VAL, device->cap_mask))
631 return false;
632 #endif
633 #endif
634
635 #if defined(CONFIG_ASYNC_PQ) || defined(CONFIG_ASYNC_PQ_MODULE)
636 if (!dma_has_cap(DMA_PQ, device->cap_mask))
637 return false;
638
639 #ifndef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
640 if (!dma_has_cap(DMA_PQ_VAL, device->cap_mask))
641 return false;
642 #endif
643 #endif
644
645 return true;
646}
647
648static int get_dma_id(struct dma_device *device)
649{
650 int rc;
651
652 idr_retry:
653 if (!idr_pre_get(&dma_idr, GFP_KERNEL))
654 return -ENOMEM;
655 mutex_lock(&dma_list_mutex);
656 rc = idr_get_new(&dma_idr, NULL, &device->dev_id);
657 mutex_unlock(&dma_list_mutex);
658 if (rc == -EAGAIN)
659 goto idr_retry;
660 else if (rc != 0)
661 return rc;
662
663 return 0;
664}
665
666/**
667 * dma_async_device_register - registers DMA devices found
668 * @device: &dma_device
669 */
670int dma_async_device_register(struct dma_device *device)
671{
672 int chancnt = 0, rc;
673 struct dma_chan* chan;
674 atomic_t *idr_ref;
675
676 if (!device)
677 return -ENODEV;
678
679 /* validate device routines */
680 BUG_ON(dma_has_cap(DMA_MEMCPY, device->cap_mask) &&
681 !device->device_prep_dma_memcpy);
682 BUG_ON(dma_has_cap(DMA_XOR, device->cap_mask) &&
683 !device->device_prep_dma_xor);
684 BUG_ON(dma_has_cap(DMA_XOR_VAL, device->cap_mask) &&
685 !device->device_prep_dma_xor_val);
686 BUG_ON(dma_has_cap(DMA_PQ, device->cap_mask) &&
687 !device->device_prep_dma_pq);
688 BUG_ON(dma_has_cap(DMA_PQ_VAL, device->cap_mask) &&
689 !device->device_prep_dma_pq_val);
690 BUG_ON(dma_has_cap(DMA_MEMSET, device->cap_mask) &&
691 !device->device_prep_dma_memset);
692 BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) &&
693 !device->device_prep_dma_interrupt);
694 BUG_ON(dma_has_cap(DMA_SG, device->cap_mask) &&
695 !device->device_prep_dma_sg);
696 BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
697 !device->device_prep_slave_sg);
698 BUG_ON(dma_has_cap(DMA_CYCLIC, device->cap_mask) &&
699 !device->device_prep_dma_cyclic);
700 BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
701 !device->device_control);
702
703 BUG_ON(!device->device_alloc_chan_resources);
704 BUG_ON(!device->device_free_chan_resources);
705 BUG_ON(!device->device_tx_status);
706 BUG_ON(!device->device_issue_pending);
707 BUG_ON(!device->dev);
708
709 /* note: this only matters in the
710 * CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH=n case
711 */
712 if (device_has_all_tx_types(device))
713 dma_cap_set(DMA_ASYNC_TX, device->cap_mask);
714
715 idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL);
716 if (!idr_ref)
717 return -ENOMEM;
718 rc = get_dma_id(device);
719 if (rc != 0) {
720 kfree(idr_ref);
721 return rc;
722 }
723
724 atomic_set(idr_ref, 0);
725
726 /* represent channels in sysfs. Probably want devs too */
727 list_for_each_entry(chan, &device->channels, device_node) {
728 rc = -ENOMEM;
729 chan->local = alloc_percpu(typeof(*chan->local));
730 if (chan->local == NULL)
731 goto err_out;
732 chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
733 if (chan->dev == NULL) {
734 free_percpu(chan->local);
735 chan->local = NULL;
736 goto err_out;
737 }
738
739 chan->chan_id = chancnt++;
740 chan->dev->device.class = &dma_devclass;
741 chan->dev->device.parent = device->dev;
742 chan->dev->chan = chan;
743 chan->dev->idr_ref = idr_ref;
744 chan->dev->dev_id = device->dev_id;
745 atomic_inc(idr_ref);
746 dev_set_name(&chan->dev->device, "dma%dchan%d",
747 device->dev_id, chan->chan_id);
748
749 rc = device_register(&chan->dev->device);
750 if (rc) {
751 free_percpu(chan->local);
752 chan->local = NULL;
753 kfree(chan->dev);
754 atomic_dec(idr_ref);
755 goto err_out;
756 }
757 chan->client_count = 0;
758 }
759 device->chancnt = chancnt;
760
761 mutex_lock(&dma_list_mutex);
762 /* take references on public channels */
763 if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
764 list_for_each_entry(chan, &device->channels, device_node) {
765 /* if clients are already waiting for channels we need
766 * to take references on their behalf
767 */
768 if (dma_chan_get(chan) == -ENODEV) {
769 /* note we can only get here for the first
770 * channel as the remaining channels are
771 * guaranteed to get a reference
772 */
773 rc = -ENODEV;
774 mutex_unlock(&dma_list_mutex);
775 goto err_out;
776 }
777 }
778 list_add_tail_rcu(&device->global_node, &dma_device_list);
779 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
780 device->privatecnt++; /* Always private */
781 dma_channel_rebalance();
782 mutex_unlock(&dma_list_mutex);
783
784 return 0;
785
786err_out:
787 /* if we never registered a channel just release the idr */
788 if (atomic_read(idr_ref) == 0) {
789 mutex_lock(&dma_list_mutex);
790 idr_remove(&dma_idr, device->dev_id);
791 mutex_unlock(&dma_list_mutex);
792 kfree(idr_ref);
793 return rc;
794 }
795
796 list_for_each_entry(chan, &device->channels, device_node) {
797 if (chan->local == NULL)
798 continue;
799 mutex_lock(&dma_list_mutex);
800 chan->dev->chan = NULL;
801 mutex_unlock(&dma_list_mutex);
802 device_unregister(&chan->dev->device);
803 free_percpu(chan->local);
804 }
805 return rc;
806}
807EXPORT_SYMBOL(dma_async_device_register);
808
809/**
810 * dma_async_device_unregister - unregister a DMA device
811 * @device: &dma_device
812 *
813 * This routine is called by dma driver exit routines, dmaengine holds module
814 * references to prevent it being called while channels are in use.
815 */
816void dma_async_device_unregister(struct dma_device *device)
817{
818 struct dma_chan *chan;
819
820 mutex_lock(&dma_list_mutex);
821 list_del_rcu(&device->global_node);
822 dma_channel_rebalance();
823 mutex_unlock(&dma_list_mutex);
824
825 list_for_each_entry(chan, &device->channels, device_node) {
826 WARN_ONCE(chan->client_count,
827 "%s called while %d clients hold a reference\n",
828 __func__, chan->client_count);
829 mutex_lock(&dma_list_mutex);
830 chan->dev->chan = NULL;
831 mutex_unlock(&dma_list_mutex);
832 device_unregister(&chan->dev->device);
833 free_percpu(chan->local);
834 }
835}
836EXPORT_SYMBOL(dma_async_device_unregister);
837
838/**
839 * dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
840 * @chan: DMA channel to offload copy to
841 * @dest: destination address (virtual)
842 * @src: source address (virtual)
843 * @len: length
844 *
845 * Both @dest and @src must be mappable to a bus address according to the
846 * DMA mapping API rules for streaming mappings.
847 * Both @dest and @src must stay memory resident (kernel memory or locked
848 * user space pages).
849 */
850dma_cookie_t
851dma_async_memcpy_buf_to_buf(struct dma_chan *chan, void *dest,
852 void *src, size_t len)
853{
854 struct dma_device *dev = chan->device;
855 struct dma_async_tx_descriptor *tx;
856 dma_addr_t dma_dest, dma_src;
857 dma_cookie_t cookie;
858 unsigned long flags;
859
860 dma_src = dma_map_single(dev->dev, src, len, DMA_TO_DEVICE);
861 dma_dest = dma_map_single(dev->dev, dest, len, DMA_FROM_DEVICE);
862 flags = DMA_CTRL_ACK |
863 DMA_COMPL_SRC_UNMAP_SINGLE |
864 DMA_COMPL_DEST_UNMAP_SINGLE;
865 tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, flags);
866
867 if (!tx) {
868 dma_unmap_single(dev->dev, dma_src, len, DMA_TO_DEVICE);
869 dma_unmap_single(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
870 return -ENOMEM;
871 }
872
873 tx->callback = NULL;
874 cookie = tx->tx_submit(tx);
875
876 preempt_disable();
877 __this_cpu_add(chan->local->bytes_transferred, len);
878 __this_cpu_inc(chan->local->memcpy_count);
879 preempt_enable();
880
881 return cookie;
882}
883EXPORT_SYMBOL(dma_async_memcpy_buf_to_buf);
884
885/**
886 * dma_async_memcpy_buf_to_pg - offloaded copy from address to page
887 * @chan: DMA channel to offload copy to
888 * @page: destination page
889 * @offset: offset in page to copy to
890 * @kdata: source address (virtual)
891 * @len: length
892 *
893 * Both @page/@offset and @kdata must be mappable to a bus address according
894 * to the DMA mapping API rules for streaming mappings.
895 * Both @page/@offset and @kdata must stay memory resident (kernel memory or
896 * locked user space pages)
897 */
898dma_cookie_t
899dma_async_memcpy_buf_to_pg(struct dma_chan *chan, struct page *page,
900 unsigned int offset, void *kdata, size_t len)
901{
902 struct dma_device *dev = chan->device;
903 struct dma_async_tx_descriptor *tx;
904 dma_addr_t dma_dest, dma_src;
905 dma_cookie_t cookie;
906 unsigned long flags;
907
908 dma_src = dma_map_single(dev->dev, kdata, len, DMA_TO_DEVICE);
909 dma_dest = dma_map_page(dev->dev, page, offset, len, DMA_FROM_DEVICE);
910 flags = DMA_CTRL_ACK | DMA_COMPL_SRC_UNMAP_SINGLE;
911 tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, flags);
912
913 if (!tx) {
914 dma_unmap_single(dev->dev, dma_src, len, DMA_TO_DEVICE);
915 dma_unmap_page(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
916 return -ENOMEM;
917 }
918
919 tx->callback = NULL;
920 cookie = tx->tx_submit(tx);
921
922 preempt_disable();
923 __this_cpu_add(chan->local->bytes_transferred, len);
924 __this_cpu_inc(chan->local->memcpy_count);
925 preempt_enable();
926
927 return cookie;
928}
929EXPORT_SYMBOL(dma_async_memcpy_buf_to_pg);
930
931/**
932 * dma_async_memcpy_pg_to_pg - offloaded copy from page to page
933 * @chan: DMA channel to offload copy to
934 * @dest_pg: destination page
935 * @dest_off: offset in page to copy to
936 * @src_pg: source page
937 * @src_off: offset in page to copy from
938 * @len: length
939 *
940 * Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
941 * address according to the DMA mapping API rules for streaming mappings.
942 * Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
943 * (kernel memory or locked user space pages).
944 */
945dma_cookie_t
946dma_async_memcpy_pg_to_pg(struct dma_chan *chan, struct page *dest_pg,
947 unsigned int dest_off, struct page *src_pg, unsigned int src_off,
948 size_t len)
949{
950 struct dma_device *dev = chan->device;
951 struct dma_async_tx_descriptor *tx;
952 dma_addr_t dma_dest, dma_src;
953 dma_cookie_t cookie;
954 unsigned long flags;
955
956 dma_src = dma_map_page(dev->dev, src_pg, src_off, len, DMA_TO_DEVICE);
957 dma_dest = dma_map_page(dev->dev, dest_pg, dest_off, len,
958 DMA_FROM_DEVICE);
959 flags = DMA_CTRL_ACK;
960 tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, flags);
961
962 if (!tx) {
963 dma_unmap_page(dev->dev, dma_src, len, DMA_TO_DEVICE);
964 dma_unmap_page(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
965 return -ENOMEM;
966 }
967
968 tx->callback = NULL;
969 cookie = tx->tx_submit(tx);
970
971 preempt_disable();
972 __this_cpu_add(chan->local->bytes_transferred, len);
973 __this_cpu_inc(chan->local->memcpy_count);
974 preempt_enable();
975
976 return cookie;
977}
978EXPORT_SYMBOL(dma_async_memcpy_pg_to_pg);
979
980void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
981 struct dma_chan *chan)
982{
983 tx->chan = chan;
984 #ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
985 spin_lock_init(&tx->lock);
986 #endif
987}
988EXPORT_SYMBOL(dma_async_tx_descriptor_init);
989
990/* dma_wait_for_async_tx - spin wait for a transaction to complete
991 * @tx: in-flight transaction to wait on
992 */
993enum dma_status
994dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
995{
996 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
997
998 if (!tx)
999 return DMA_SUCCESS;
1000
1001 while (tx->cookie == -EBUSY) {
1002 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
1003 pr_err("%s timeout waiting for descriptor submission\n",
1004 __func__);
1005 return DMA_ERROR;
1006 }
1007 cpu_relax();
1008 }
1009 return dma_sync_wait(tx->chan, tx->cookie);
1010}
1011EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
1012
1013/* dma_run_dependencies - helper routine for dma drivers to process
1014 * (start) dependent operations on their target channel
1015 * @tx: transaction with dependencies
1016 */
1017void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
1018{
1019 struct dma_async_tx_descriptor *dep = txd_next(tx);
1020 struct dma_async_tx_descriptor *dep_next;
1021 struct dma_chan *chan;
1022
1023 if (!dep)
1024 return;
1025
1026 /* we'll submit tx->next now, so clear the link */
1027 txd_clear_next(tx);
1028 chan = dep->chan;
1029
1030 /* keep submitting up until a channel switch is detected
1031 * in that case we will be called again as a result of
1032 * processing the interrupt from async_tx_channel_switch
1033 */
1034 for (; dep; dep = dep_next) {
1035 txd_lock(dep);
1036 txd_clear_parent(dep);
1037 dep_next = txd_next(dep);
1038 if (dep_next && dep_next->chan == chan)
1039 txd_clear_next(dep); /* ->next will be submitted */
1040 else
1041 dep_next = NULL; /* submit current dep and terminate */
1042 txd_unlock(dep);
1043
1044 dep->tx_submit(dep);
1045 }
1046
1047 chan->device->device_issue_pending(chan);
1048}
1049EXPORT_SYMBOL_GPL(dma_run_dependencies);
1050
1051static int __init dma_bus_init(void)
1052{
1053 return class_register(&dma_devclass);
1054}
1055arch_initcall(dma_bus_init);
1056
1057
1/*
2 * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
3 *
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)
7 * any later version.
8 *
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
12 * more details.
13 *
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.
17 *
18 * The full GNU General Public License is included in this distribution in the
19 * file called COPYING.
20 */
21
22/*
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
26 * this capability.
27 *
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,
30 * such as locking.
31 *
32 * LOCKING:
33 *
34 * The subsystem keeps a global list of dma_device structs it is protected by a
35 * mutex, dma_list_mutex.
36 *
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.
41 *
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.
44 *
45 * See Documentation/dmaengine.txt for more details
46 */
47
48#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
49
50#include <linux/dma-mapping.h>
51#include <linux/init.h>
52#include <linux/module.h>
53#include <linux/mm.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>
69
70static DEFINE_MUTEX(dma_list_mutex);
71static DEFINE_IDR(dma_idr);
72static LIST_HEAD(dma_device_list);
73static long dmaengine_ref_count;
74
75/* --- sysfs implementation --- */
76
77/**
78 * dev_to_dma_chan - convert a device pointer to the its sysfs container object
79 * @dev - device node
80 *
81 * Must be called under dma_list_mutex
82 */
83static struct dma_chan *dev_to_dma_chan(struct device *dev)
84{
85 struct dma_chan_dev *chan_dev;
86
87 chan_dev = container_of(dev, typeof(*chan_dev), device);
88 return chan_dev->chan;
89}
90
91static ssize_t memcpy_count_show(struct device *dev,
92 struct device_attribute *attr, char *buf)
93{
94 struct dma_chan *chan;
95 unsigned long count = 0;
96 int i;
97 int err;
98
99 mutex_lock(&dma_list_mutex);
100 chan = dev_to_dma_chan(dev);
101 if (chan) {
102 for_each_possible_cpu(i)
103 count += per_cpu_ptr(chan->local, i)->memcpy_count;
104 err = sprintf(buf, "%lu\n", count);
105 } else
106 err = -ENODEV;
107 mutex_unlock(&dma_list_mutex);
108
109 return err;
110}
111static DEVICE_ATTR_RO(memcpy_count);
112
113static ssize_t bytes_transferred_show(struct device *dev,
114 struct device_attribute *attr, char *buf)
115{
116 struct dma_chan *chan;
117 unsigned long count = 0;
118 int i;
119 int err;
120
121 mutex_lock(&dma_list_mutex);
122 chan = dev_to_dma_chan(dev);
123 if (chan) {
124 for_each_possible_cpu(i)
125 count += per_cpu_ptr(chan->local, i)->bytes_transferred;
126 err = sprintf(buf, "%lu\n", count);
127 } else
128 err = -ENODEV;
129 mutex_unlock(&dma_list_mutex);
130
131 return err;
132}
133static DEVICE_ATTR_RO(bytes_transferred);
134
135static ssize_t in_use_show(struct device *dev, struct device_attribute *attr,
136 char *buf)
137{
138 struct dma_chan *chan;
139 int err;
140
141 mutex_lock(&dma_list_mutex);
142 chan = dev_to_dma_chan(dev);
143 if (chan)
144 err = sprintf(buf, "%d\n", chan->client_count);
145 else
146 err = -ENODEV;
147 mutex_unlock(&dma_list_mutex);
148
149 return err;
150}
151static DEVICE_ATTR_RO(in_use);
152
153static struct attribute *dma_dev_attrs[] = {
154 &dev_attr_memcpy_count.attr,
155 &dev_attr_bytes_transferred.attr,
156 &dev_attr_in_use.attr,
157 NULL,
158};
159ATTRIBUTE_GROUPS(dma_dev);
160
161static void chan_dev_release(struct device *dev)
162{
163 struct dma_chan_dev *chan_dev;
164
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);
171 }
172 kfree(chan_dev);
173}
174
175static struct class dma_devclass = {
176 .name = "dma",
177 .dev_groups = dma_dev_groups,
178 .dev_release = chan_dev_release,
179};
180
181/* --- client and device registration --- */
182
183#define dma_device_satisfies_mask(device, mask) \
184 __dma_device_satisfies_mask((device), &(mask))
185static int
186__dma_device_satisfies_mask(struct dma_device *device,
187 const dma_cap_mask_t *want)
188{
189 dma_cap_mask_t has;
190
191 bitmap_and(has.bits, want->bits, device->cap_mask.bits,
192 DMA_TX_TYPE_END);
193 return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END);
194}
195
196static struct module *dma_chan_to_owner(struct dma_chan *chan)
197{
198 return chan->device->dev->driver->owner;
199}
200
201/**
202 * balance_ref_count - catch up the channel reference count
203 * @chan - channel to balance ->client_count versus dmaengine_ref_count
204 *
205 * balance_ref_count must be called under dma_list_mutex
206 */
207static void balance_ref_count(struct dma_chan *chan)
208{
209 struct module *owner = dma_chan_to_owner(chan);
210
211 while (chan->client_count < dmaengine_ref_count) {
212 __module_get(owner);
213 chan->client_count++;
214 }
215}
216
217/**
218 * dma_chan_get - try to grab a dma channel's parent driver module
219 * @chan - channel to grab
220 *
221 * Must be called under dma_list_mutex
222 */
223static int dma_chan_get(struct dma_chan *chan)
224{
225 int err = -ENODEV;
226 struct module *owner = dma_chan_to_owner(chan);
227
228 if (chan->client_count) {
229 __module_get(owner);
230 err = 0;
231 } else if (try_module_get(owner))
232 err = 0;
233
234 if (err == 0)
235 chan->client_count++;
236
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);
240
241 if (desc_cnt < 0) {
242 err = desc_cnt;
243 chan->client_count = 0;
244 module_put(owner);
245 } else if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
246 balance_ref_count(chan);
247 }
248
249 return err;
250}
251
252/**
253 * dma_chan_put - drop a reference to a dma channel's parent driver module
254 * @chan - channel to release
255 *
256 * Must be called under dma_list_mutex
257 */
258static void dma_chan_put(struct dma_chan *chan)
259{
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);
266}
267
268enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
269{
270 enum dma_status status;
271 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
272
273 dma_async_issue_pending(chan);
274 do {
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__);
278 return DMA_ERROR;
279 }
280 if (status != DMA_IN_PROGRESS)
281 break;
282 cpu_relax();
283 } while (1);
284
285 return status;
286}
287EXPORT_SYMBOL(dma_sync_wait);
288
289/**
290 * dma_cap_mask_all - enable iteration over all operation types
291 */
292static dma_cap_mask_t dma_cap_mask_all;
293
294/**
295 * dma_chan_tbl_ent - tracks channel allocations per core/operation
296 * @chan - associated channel for this entry
297 */
298struct dma_chan_tbl_ent {
299 struct dma_chan *chan;
300};
301
302/**
303 * channel_table - percpu lookup table for memory-to-memory offload providers
304 */
305static struct dma_chan_tbl_ent __percpu *channel_table[DMA_TX_TYPE_END];
306
307static int __init dma_channel_table_init(void)
308{
309 enum dma_transaction_type cap;
310 int err = 0;
311
312 bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END);
313
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
317 */
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);
321
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]) {
325 err = -ENOMEM;
326 break;
327 }
328 }
329
330 if (err) {
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]);
335 }
336
337 return err;
338}
339arch_initcall(dma_channel_table_init);
340
341/**
342 * dma_find_channel - find a channel to carry out the operation
343 * @tx_type: transaction type
344 */
345struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
346{
347 return this_cpu_read(channel_table[tx_type]->chan);
348}
349EXPORT_SYMBOL(dma_find_channel);
350
351/*
352 * net_dma_find_channel - find a channel for net_dma
353 * net_dma has alignment requirements
354 */
355struct dma_chan *net_dma_find_channel(void)
356{
357 struct dma_chan *chan = dma_find_channel(DMA_MEMCPY);
358 if (chan && !is_dma_copy_aligned(chan->device, 1, 1, 1))
359 return NULL;
360
361 return chan;
362}
363EXPORT_SYMBOL(net_dma_find_channel);
364
365/**
366 * dma_issue_pending_all - flush all pending operations across all channels
367 */
368void dma_issue_pending_all(void)
369{
370 struct dma_device *device;
371 struct dma_chan *chan;
372
373 rcu_read_lock();
374 list_for_each_entry_rcu(device, &dma_device_list, global_node) {
375 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
376 continue;
377 list_for_each_entry(chan, &device->channels, device_node)
378 if (chan->client_count)
379 device->device_issue_pending(chan);
380 }
381 rcu_read_unlock();
382}
383EXPORT_SYMBOL(dma_issue_pending_all);
384
385/**
386 * dma_chan_is_local - returns true if the channel is in the same numa-node as the cpu
387 */
388static bool dma_chan_is_local(struct dma_chan *chan, int cpu)
389{
390 int node = dev_to_node(chan->device->dev);
391 return node == -1 || cpumask_test_cpu(cpu, cpumask_of_node(node));
392}
393
394/**
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
398 *
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.
403 */
404static struct dma_chan *min_chan(enum dma_transaction_type cap, int cpu)
405{
406 struct dma_device *device;
407 struct dma_chan *chan;
408 struct dma_chan *min = NULL;
409 struct dma_chan *localmin = NULL;
410
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))
414 continue;
415 list_for_each_entry(chan, &device->channels, device_node) {
416 if (!chan->client_count)
417 continue;
418 if (!min || chan->table_count < min->table_count)
419 min = chan;
420
421 if (dma_chan_is_local(chan, cpu))
422 if (!localmin ||
423 chan->table_count < localmin->table_count)
424 localmin = chan;
425 }
426 }
427
428 chan = localmin ? localmin : min;
429
430 if (chan)
431 chan->table_count++;
432
433 return chan;
434}
435
436/**
437 * dma_channel_rebalance - redistribute the available channels
438 *
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
442 * dma_list_mutex.
443 */
444static void dma_channel_rebalance(void)
445{
446 struct dma_chan *chan;
447 struct dma_device *device;
448 int cpu;
449 int cap;
450
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;
455
456 list_for_each_entry(device, &dma_device_list, global_node) {
457 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
458 continue;
459 list_for_each_entry(chan, &device->channels, device_node)
460 chan->table_count = 0;
461 }
462
463 /* don't populate the channel_table if no clients are available */
464 if (!dmaengine_ref_count)
465 return;
466
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;
472 }
473}
474
475static struct dma_chan *private_candidate(const dma_cap_mask_t *mask,
476 struct dma_device *dev,
477 dma_filter_fn fn, void *fn_param)
478{
479 struct dma_chan *chan;
480
481 if (!__dma_device_satisfies_mask(dev, mask)) {
482 pr_debug("%s: wrong capabilities\n", __func__);
483 return NULL;
484 }
485 /* devices with multiple channels need special handling as we need to
486 * ensure that all channels are either private or public.
487 */
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)
492 return NULL;
493 }
494
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));
499 continue;
500 }
501 if (fn && !fn(chan, fn_param)) {
502 pr_debug("%s: %s filter said false\n",
503 __func__, dma_chan_name(chan));
504 continue;
505 }
506 return chan;
507 }
508
509 return NULL;
510}
511
512/**
513 * dma_request_slave_channel - try to get specific channel exclusively
514 * @chan: target channel
515 */
516struct dma_chan *dma_get_slave_channel(struct dma_chan *chan)
517{
518 int err = -EBUSY;
519
520 /* lock against __dma_request_channel */
521 mutex_lock(&dma_list_mutex);
522
523 if (chan->client_count == 0) {
524 err = dma_chan_get(chan);
525 if (err)
526 pr_debug("%s: failed to get %s: (%d)\n",
527 __func__, dma_chan_name(chan), err);
528 } else
529 chan = NULL;
530
531 mutex_unlock(&dma_list_mutex);
532
533
534 return chan;
535}
536EXPORT_SYMBOL_GPL(dma_get_slave_channel);
537
538struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)
539{
540 dma_cap_mask_t mask;
541 struct dma_chan *chan;
542 int err;
543
544 dma_cap_zero(mask);
545 dma_cap_set(DMA_SLAVE, mask);
546
547 /* lock against __dma_request_channel */
548 mutex_lock(&dma_list_mutex);
549
550 chan = private_candidate(&mask, device, NULL, NULL);
551 if (chan) {
552 err = dma_chan_get(chan);
553 if (err) {
554 pr_debug("%s: failed to get %s: (%d)\n",
555 __func__, dma_chan_name(chan), err);
556 chan = NULL;
557 }
558 }
559
560 mutex_unlock(&dma_list_mutex);
561
562 return chan;
563}
564EXPORT_SYMBOL_GPL(dma_get_any_slave_channel);
565
566/**
567 * __dma_request_channel - try to allocate an exclusive channel
568 * @mask: capabilities that the channel must satisfy
569 * @fn: optional callback to disposition available channels
570 * @fn_param: opaque parameter to pass to dma_filter_fn
571 *
572 * Returns pointer to appropriate DMA channel on success or NULL.
573 */
574struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
575 dma_filter_fn fn, void *fn_param)
576{
577 struct dma_device *device, *_d;
578 struct dma_chan *chan = NULL;
579 int err;
580
581 /* Find a channel */
582 mutex_lock(&dma_list_mutex);
583 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
584 chan = private_candidate(mask, device, fn, fn_param);
585 if (chan) {
586 /* Found a suitable channel, try to grab, prep, and
587 * return it. We first set DMA_PRIVATE to disable
588 * balance_ref_count as this channel will not be
589 * published in the general-purpose allocator
590 */
591 dma_cap_set(DMA_PRIVATE, device->cap_mask);
592 device->privatecnt++;
593 err = dma_chan_get(chan);
594
595 if (err == -ENODEV) {
596 pr_debug("%s: %s module removed\n",
597 __func__, dma_chan_name(chan));
598 list_del_rcu(&device->global_node);
599 } else if (err)
600 pr_debug("%s: failed to get %s: (%d)\n",
601 __func__, dma_chan_name(chan), err);
602 else
603 break;
604 if (--device->privatecnt == 0)
605 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
606 chan = NULL;
607 }
608 }
609 mutex_unlock(&dma_list_mutex);
610
611 pr_debug("%s: %s (%s)\n",
612 __func__,
613 chan ? "success" : "fail",
614 chan ? dma_chan_name(chan) : NULL);
615
616 return chan;
617}
618EXPORT_SYMBOL_GPL(__dma_request_channel);
619
620/**
621 * dma_request_slave_channel - try to allocate an exclusive slave channel
622 * @dev: pointer to client device structure
623 * @name: slave channel name
624 *
625 * Returns pointer to appropriate DMA channel on success or an error pointer.
626 */
627struct dma_chan *dma_request_slave_channel_reason(struct device *dev,
628 const char *name)
629{
630 /* If device-tree is present get slave info from here */
631 if (dev->of_node)
632 return of_dma_request_slave_channel(dev->of_node, name);
633
634 /* If device was enumerated by ACPI get slave info from here */
635 if (ACPI_HANDLE(dev))
636 return acpi_dma_request_slave_chan_by_name(dev, name);
637
638 return ERR_PTR(-ENODEV);
639}
640EXPORT_SYMBOL_GPL(dma_request_slave_channel_reason);
641
642/**
643 * dma_request_slave_channel - try to allocate an exclusive slave channel
644 * @dev: pointer to client device structure
645 * @name: slave channel name
646 *
647 * Returns pointer to appropriate DMA channel on success or NULL.
648 */
649struct dma_chan *dma_request_slave_channel(struct device *dev,
650 const char *name)
651{
652 struct dma_chan *ch = dma_request_slave_channel_reason(dev, name);
653 if (IS_ERR(ch))
654 return NULL;
655 return ch;
656}
657EXPORT_SYMBOL_GPL(dma_request_slave_channel);
658
659void dma_release_channel(struct dma_chan *chan)
660{
661 mutex_lock(&dma_list_mutex);
662 WARN_ONCE(chan->client_count != 1,
663 "chan reference count %d != 1\n", chan->client_count);
664 dma_chan_put(chan);
665 /* drop PRIVATE cap enabled by __dma_request_channel() */
666 if (--chan->device->privatecnt == 0)
667 dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
668 mutex_unlock(&dma_list_mutex);
669}
670EXPORT_SYMBOL_GPL(dma_release_channel);
671
672/**
673 * dmaengine_get - register interest in dma_channels
674 */
675void dmaengine_get(void)
676{
677 struct dma_device *device, *_d;
678 struct dma_chan *chan;
679 int err;
680
681 mutex_lock(&dma_list_mutex);
682 dmaengine_ref_count++;
683
684 /* try to grab channels */
685 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
686 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
687 continue;
688 list_for_each_entry(chan, &device->channels, device_node) {
689 err = dma_chan_get(chan);
690 if (err == -ENODEV) {
691 /* module removed before we could use it */
692 list_del_rcu(&device->global_node);
693 break;
694 } else if (err)
695 pr_debug("%s: failed to get %s: (%d)\n",
696 __func__, dma_chan_name(chan), err);
697 }
698 }
699
700 /* if this is the first reference and there were channels
701 * waiting we need to rebalance to get those channels
702 * incorporated into the channel table
703 */
704 if (dmaengine_ref_count == 1)
705 dma_channel_rebalance();
706 mutex_unlock(&dma_list_mutex);
707}
708EXPORT_SYMBOL(dmaengine_get);
709
710/**
711 * dmaengine_put - let dma drivers be removed when ref_count == 0
712 */
713void dmaengine_put(void)
714{
715 struct dma_device *device;
716 struct dma_chan *chan;
717
718 mutex_lock(&dma_list_mutex);
719 dmaengine_ref_count--;
720 BUG_ON(dmaengine_ref_count < 0);
721 /* drop channel references */
722 list_for_each_entry(device, &dma_device_list, global_node) {
723 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
724 continue;
725 list_for_each_entry(chan, &device->channels, device_node)
726 dma_chan_put(chan);
727 }
728 mutex_unlock(&dma_list_mutex);
729}
730EXPORT_SYMBOL(dmaengine_put);
731
732static bool device_has_all_tx_types(struct dma_device *device)
733{
734 /* A device that satisfies this test has channels that will never cause
735 * an async_tx channel switch event as all possible operation types can
736 * be handled.
737 */
738 #ifdef CONFIG_ASYNC_TX_DMA
739 if (!dma_has_cap(DMA_INTERRUPT, device->cap_mask))
740 return false;
741 #endif
742
743 #if defined(CONFIG_ASYNC_MEMCPY) || defined(CONFIG_ASYNC_MEMCPY_MODULE)
744 if (!dma_has_cap(DMA_MEMCPY, device->cap_mask))
745 return false;
746 #endif
747
748 #if defined(CONFIG_ASYNC_XOR) || defined(CONFIG_ASYNC_XOR_MODULE)
749 if (!dma_has_cap(DMA_XOR, device->cap_mask))
750 return false;
751
752 #ifndef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
753 if (!dma_has_cap(DMA_XOR_VAL, device->cap_mask))
754 return false;
755 #endif
756 #endif
757
758 #if defined(CONFIG_ASYNC_PQ) || defined(CONFIG_ASYNC_PQ_MODULE)
759 if (!dma_has_cap(DMA_PQ, device->cap_mask))
760 return false;
761
762 #ifndef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
763 if (!dma_has_cap(DMA_PQ_VAL, device->cap_mask))
764 return false;
765 #endif
766 #endif
767
768 return true;
769}
770
771static int get_dma_id(struct dma_device *device)
772{
773 int rc;
774
775 mutex_lock(&dma_list_mutex);
776
777 rc = idr_alloc(&dma_idr, NULL, 0, 0, GFP_KERNEL);
778 if (rc >= 0)
779 device->dev_id = rc;
780
781 mutex_unlock(&dma_list_mutex);
782 return rc < 0 ? rc : 0;
783}
784
785/**
786 * dma_async_device_register - registers DMA devices found
787 * @device: &dma_device
788 */
789int dma_async_device_register(struct dma_device *device)
790{
791 int chancnt = 0, rc;
792 struct dma_chan* chan;
793 atomic_t *idr_ref;
794
795 if (!device)
796 return -ENODEV;
797
798 /* validate device routines */
799 BUG_ON(dma_has_cap(DMA_MEMCPY, device->cap_mask) &&
800 !device->device_prep_dma_memcpy);
801 BUG_ON(dma_has_cap(DMA_XOR, device->cap_mask) &&
802 !device->device_prep_dma_xor);
803 BUG_ON(dma_has_cap(DMA_XOR_VAL, device->cap_mask) &&
804 !device->device_prep_dma_xor_val);
805 BUG_ON(dma_has_cap(DMA_PQ, device->cap_mask) &&
806 !device->device_prep_dma_pq);
807 BUG_ON(dma_has_cap(DMA_PQ_VAL, device->cap_mask) &&
808 !device->device_prep_dma_pq_val);
809 BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) &&
810 !device->device_prep_dma_interrupt);
811 BUG_ON(dma_has_cap(DMA_SG, device->cap_mask) &&
812 !device->device_prep_dma_sg);
813 BUG_ON(dma_has_cap(DMA_CYCLIC, device->cap_mask) &&
814 !device->device_prep_dma_cyclic);
815 BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
816 !device->device_control);
817 BUG_ON(dma_has_cap(DMA_INTERLEAVE, device->cap_mask) &&
818 !device->device_prep_interleaved_dma);
819
820 BUG_ON(!device->device_alloc_chan_resources);
821 BUG_ON(!device->device_free_chan_resources);
822 BUG_ON(!device->device_tx_status);
823 BUG_ON(!device->device_issue_pending);
824 BUG_ON(!device->dev);
825
826 /* note: this only matters in the
827 * CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH=n case
828 */
829 if (device_has_all_tx_types(device))
830 dma_cap_set(DMA_ASYNC_TX, device->cap_mask);
831
832 idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL);
833 if (!idr_ref)
834 return -ENOMEM;
835 rc = get_dma_id(device);
836 if (rc != 0) {
837 kfree(idr_ref);
838 return rc;
839 }
840
841 atomic_set(idr_ref, 0);
842
843 /* represent channels in sysfs. Probably want devs too */
844 list_for_each_entry(chan, &device->channels, device_node) {
845 rc = -ENOMEM;
846 chan->local = alloc_percpu(typeof(*chan->local));
847 if (chan->local == NULL)
848 goto err_out;
849 chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
850 if (chan->dev == NULL) {
851 free_percpu(chan->local);
852 chan->local = NULL;
853 goto err_out;
854 }
855
856 chan->chan_id = chancnt++;
857 chan->dev->device.class = &dma_devclass;
858 chan->dev->device.parent = device->dev;
859 chan->dev->chan = chan;
860 chan->dev->idr_ref = idr_ref;
861 chan->dev->dev_id = device->dev_id;
862 atomic_inc(idr_ref);
863 dev_set_name(&chan->dev->device, "dma%dchan%d",
864 device->dev_id, chan->chan_id);
865
866 rc = device_register(&chan->dev->device);
867 if (rc) {
868 free_percpu(chan->local);
869 chan->local = NULL;
870 kfree(chan->dev);
871 atomic_dec(idr_ref);
872 goto err_out;
873 }
874 chan->client_count = 0;
875 }
876 device->chancnt = chancnt;
877
878 mutex_lock(&dma_list_mutex);
879 /* take references on public channels */
880 if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
881 list_for_each_entry(chan, &device->channels, device_node) {
882 /* if clients are already waiting for channels we need
883 * to take references on their behalf
884 */
885 if (dma_chan_get(chan) == -ENODEV) {
886 /* note we can only get here for the first
887 * channel as the remaining channels are
888 * guaranteed to get a reference
889 */
890 rc = -ENODEV;
891 mutex_unlock(&dma_list_mutex);
892 goto err_out;
893 }
894 }
895 list_add_tail_rcu(&device->global_node, &dma_device_list);
896 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
897 device->privatecnt++; /* Always private */
898 dma_channel_rebalance();
899 mutex_unlock(&dma_list_mutex);
900
901 return 0;
902
903err_out:
904 /* if we never registered a channel just release the idr */
905 if (atomic_read(idr_ref) == 0) {
906 mutex_lock(&dma_list_mutex);
907 idr_remove(&dma_idr, device->dev_id);
908 mutex_unlock(&dma_list_mutex);
909 kfree(idr_ref);
910 return rc;
911 }
912
913 list_for_each_entry(chan, &device->channels, device_node) {
914 if (chan->local == NULL)
915 continue;
916 mutex_lock(&dma_list_mutex);
917 chan->dev->chan = NULL;
918 mutex_unlock(&dma_list_mutex);
919 device_unregister(&chan->dev->device);
920 free_percpu(chan->local);
921 }
922 return rc;
923}
924EXPORT_SYMBOL(dma_async_device_register);
925
926/**
927 * dma_async_device_unregister - unregister a DMA device
928 * @device: &dma_device
929 *
930 * This routine is called by dma driver exit routines, dmaengine holds module
931 * references to prevent it being called while channels are in use.
932 */
933void dma_async_device_unregister(struct dma_device *device)
934{
935 struct dma_chan *chan;
936
937 mutex_lock(&dma_list_mutex);
938 list_del_rcu(&device->global_node);
939 dma_channel_rebalance();
940 mutex_unlock(&dma_list_mutex);
941
942 list_for_each_entry(chan, &device->channels, device_node) {
943 WARN_ONCE(chan->client_count,
944 "%s called while %d clients hold a reference\n",
945 __func__, chan->client_count);
946 mutex_lock(&dma_list_mutex);
947 chan->dev->chan = NULL;
948 mutex_unlock(&dma_list_mutex);
949 device_unregister(&chan->dev->device);
950 free_percpu(chan->local);
951 }
952}
953EXPORT_SYMBOL(dma_async_device_unregister);
954
955struct dmaengine_unmap_pool {
956 struct kmem_cache *cache;
957 const char *name;
958 mempool_t *pool;
959 size_t size;
960};
961
962#define __UNMAP_POOL(x) { .size = x, .name = "dmaengine-unmap-" __stringify(x) }
963static struct dmaengine_unmap_pool unmap_pool[] = {
964 __UNMAP_POOL(2),
965 #if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
966 __UNMAP_POOL(16),
967 __UNMAP_POOL(128),
968 __UNMAP_POOL(256),
969 #endif
970};
971
972static struct dmaengine_unmap_pool *__get_unmap_pool(int nr)
973{
974 int order = get_count_order(nr);
975
976 switch (order) {
977 case 0 ... 1:
978 return &unmap_pool[0];
979 case 2 ... 4:
980 return &unmap_pool[1];
981 case 5 ... 7:
982 return &unmap_pool[2];
983 case 8:
984 return &unmap_pool[3];
985 default:
986 BUG();
987 return NULL;
988 }
989}
990
991static void dmaengine_unmap(struct kref *kref)
992{
993 struct dmaengine_unmap_data *unmap = container_of(kref, typeof(*unmap), kref);
994 struct device *dev = unmap->dev;
995 int cnt, i;
996
997 cnt = unmap->to_cnt;
998 for (i = 0; i < cnt; i++)
999 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1000 DMA_TO_DEVICE);
1001 cnt += unmap->from_cnt;
1002 for (; i < cnt; i++)
1003 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1004 DMA_FROM_DEVICE);
1005 cnt += unmap->bidi_cnt;
1006 for (; i < cnt; i++) {
1007 if (unmap->addr[i] == 0)
1008 continue;
1009 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1010 DMA_BIDIRECTIONAL);
1011 }
1012 cnt = unmap->map_cnt;
1013 mempool_free(unmap, __get_unmap_pool(cnt)->pool);
1014}
1015
1016void dmaengine_unmap_put(struct dmaengine_unmap_data *unmap)
1017{
1018 if (unmap)
1019 kref_put(&unmap->kref, dmaengine_unmap);
1020}
1021EXPORT_SYMBOL_GPL(dmaengine_unmap_put);
1022
1023static void dmaengine_destroy_unmap_pool(void)
1024{
1025 int i;
1026
1027 for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
1028 struct dmaengine_unmap_pool *p = &unmap_pool[i];
1029
1030 if (p->pool)
1031 mempool_destroy(p->pool);
1032 p->pool = NULL;
1033 if (p->cache)
1034 kmem_cache_destroy(p->cache);
1035 p->cache = NULL;
1036 }
1037}
1038
1039static int __init dmaengine_init_unmap_pool(void)
1040{
1041 int i;
1042
1043 for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
1044 struct dmaengine_unmap_pool *p = &unmap_pool[i];
1045 size_t size;
1046
1047 size = sizeof(struct dmaengine_unmap_data) +
1048 sizeof(dma_addr_t) * p->size;
1049
1050 p->cache = kmem_cache_create(p->name, size, 0,
1051 SLAB_HWCACHE_ALIGN, NULL);
1052 if (!p->cache)
1053 break;
1054 p->pool = mempool_create_slab_pool(1, p->cache);
1055 if (!p->pool)
1056 break;
1057 }
1058
1059 if (i == ARRAY_SIZE(unmap_pool))
1060 return 0;
1061
1062 dmaengine_destroy_unmap_pool();
1063 return -ENOMEM;
1064}
1065
1066struct dmaengine_unmap_data *
1067dmaengine_get_unmap_data(struct device *dev, int nr, gfp_t flags)
1068{
1069 struct dmaengine_unmap_data *unmap;
1070
1071 unmap = mempool_alloc(__get_unmap_pool(nr)->pool, flags);
1072 if (!unmap)
1073 return NULL;
1074
1075 memset(unmap, 0, sizeof(*unmap));
1076 kref_init(&unmap->kref);
1077 unmap->dev = dev;
1078 unmap->map_cnt = nr;
1079
1080 return unmap;
1081}
1082EXPORT_SYMBOL(dmaengine_get_unmap_data);
1083
1084/**
1085 * dma_async_memcpy_pg_to_pg - offloaded copy from page to page
1086 * @chan: DMA channel to offload copy to
1087 * @dest_pg: destination page
1088 * @dest_off: offset in page to copy to
1089 * @src_pg: source page
1090 * @src_off: offset in page to copy from
1091 * @len: length
1092 *
1093 * Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
1094 * address according to the DMA mapping API rules for streaming mappings.
1095 * Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
1096 * (kernel memory or locked user space pages).
1097 */
1098dma_cookie_t
1099dma_async_memcpy_pg_to_pg(struct dma_chan *chan, struct page *dest_pg,
1100 unsigned int dest_off, struct page *src_pg, unsigned int src_off,
1101 size_t len)
1102{
1103 struct dma_device *dev = chan->device;
1104 struct dma_async_tx_descriptor *tx;
1105 struct dmaengine_unmap_data *unmap;
1106 dma_cookie_t cookie;
1107 unsigned long flags;
1108
1109 unmap = dmaengine_get_unmap_data(dev->dev, 2, GFP_NOWAIT);
1110 if (!unmap)
1111 return -ENOMEM;
1112
1113 unmap->to_cnt = 1;
1114 unmap->from_cnt = 1;
1115 unmap->addr[0] = dma_map_page(dev->dev, src_pg, src_off, len,
1116 DMA_TO_DEVICE);
1117 unmap->addr[1] = dma_map_page(dev->dev, dest_pg, dest_off, len,
1118 DMA_FROM_DEVICE);
1119 unmap->len = len;
1120 flags = DMA_CTRL_ACK;
1121 tx = dev->device_prep_dma_memcpy(chan, unmap->addr[1], unmap->addr[0],
1122 len, flags);
1123
1124 if (!tx) {
1125 dmaengine_unmap_put(unmap);
1126 return -ENOMEM;
1127 }
1128
1129 dma_set_unmap(tx, unmap);
1130 cookie = tx->tx_submit(tx);
1131 dmaengine_unmap_put(unmap);
1132
1133 preempt_disable();
1134 __this_cpu_add(chan->local->bytes_transferred, len);
1135 __this_cpu_inc(chan->local->memcpy_count);
1136 preempt_enable();
1137
1138 return cookie;
1139}
1140EXPORT_SYMBOL(dma_async_memcpy_pg_to_pg);
1141
1142/**
1143 * dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
1144 * @chan: DMA channel to offload copy to
1145 * @dest: destination address (virtual)
1146 * @src: source address (virtual)
1147 * @len: length
1148 *
1149 * Both @dest and @src must be mappable to a bus address according to the
1150 * DMA mapping API rules for streaming mappings.
1151 * Both @dest and @src must stay memory resident (kernel memory or locked
1152 * user space pages).
1153 */
1154dma_cookie_t
1155dma_async_memcpy_buf_to_buf(struct dma_chan *chan, void *dest,
1156 void *src, size_t len)
1157{
1158 return dma_async_memcpy_pg_to_pg(chan, virt_to_page(dest),
1159 (unsigned long) dest & ~PAGE_MASK,
1160 virt_to_page(src),
1161 (unsigned long) src & ~PAGE_MASK, len);
1162}
1163EXPORT_SYMBOL(dma_async_memcpy_buf_to_buf);
1164
1165/**
1166 * dma_async_memcpy_buf_to_pg - offloaded copy from address to page
1167 * @chan: DMA channel to offload copy to
1168 * @page: destination page
1169 * @offset: offset in page to copy to
1170 * @kdata: source address (virtual)
1171 * @len: length
1172 *
1173 * Both @page/@offset and @kdata must be mappable to a bus address according
1174 * to the DMA mapping API rules for streaming mappings.
1175 * Both @page/@offset and @kdata must stay memory resident (kernel memory or
1176 * locked user space pages)
1177 */
1178dma_cookie_t
1179dma_async_memcpy_buf_to_pg(struct dma_chan *chan, struct page *page,
1180 unsigned int offset, void *kdata, size_t len)
1181{
1182 return dma_async_memcpy_pg_to_pg(chan, page, offset,
1183 virt_to_page(kdata),
1184 (unsigned long) kdata & ~PAGE_MASK, len);
1185}
1186EXPORT_SYMBOL(dma_async_memcpy_buf_to_pg);
1187
1188void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
1189 struct dma_chan *chan)
1190{
1191 tx->chan = chan;
1192 #ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
1193 spin_lock_init(&tx->lock);
1194 #endif
1195}
1196EXPORT_SYMBOL(dma_async_tx_descriptor_init);
1197
1198/* dma_wait_for_async_tx - spin wait for a transaction to complete
1199 * @tx: in-flight transaction to wait on
1200 */
1201enum dma_status
1202dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
1203{
1204 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
1205
1206 if (!tx)
1207 return DMA_COMPLETE;
1208
1209 while (tx->cookie == -EBUSY) {
1210 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
1211 pr_err("%s timeout waiting for descriptor submission\n",
1212 __func__);
1213 return DMA_ERROR;
1214 }
1215 cpu_relax();
1216 }
1217 return dma_sync_wait(tx->chan, tx->cookie);
1218}
1219EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
1220
1221/* dma_run_dependencies - helper routine for dma drivers to process
1222 * (start) dependent operations on their target channel
1223 * @tx: transaction with dependencies
1224 */
1225void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
1226{
1227 struct dma_async_tx_descriptor *dep = txd_next(tx);
1228 struct dma_async_tx_descriptor *dep_next;
1229 struct dma_chan *chan;
1230
1231 if (!dep)
1232 return;
1233
1234 /* we'll submit tx->next now, so clear the link */
1235 txd_clear_next(tx);
1236 chan = dep->chan;
1237
1238 /* keep submitting up until a channel switch is detected
1239 * in that case we will be called again as a result of
1240 * processing the interrupt from async_tx_channel_switch
1241 */
1242 for (; dep; dep = dep_next) {
1243 txd_lock(dep);
1244 txd_clear_parent(dep);
1245 dep_next = txd_next(dep);
1246 if (dep_next && dep_next->chan == chan)
1247 txd_clear_next(dep); /* ->next will be submitted */
1248 else
1249 dep_next = NULL; /* submit current dep and terminate */
1250 txd_unlock(dep);
1251
1252 dep->tx_submit(dep);
1253 }
1254
1255 chan->device->device_issue_pending(chan);
1256}
1257EXPORT_SYMBOL_GPL(dma_run_dependencies);
1258
1259static int __init dma_bus_init(void)
1260{
1261 int err = dmaengine_init_unmap_pool();
1262
1263 if (err)
1264 return err;
1265 return class_register(&dma_devclass);
1266}
1267arch_initcall(dma_bus_init);
1268
1269