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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 * The full GNU General Public License is included in this distribution in the
15 * file called COPYING.
16 */
17
18/*
19 * This code implements the DMA subsystem. It provides a HW-neutral interface
20 * for other kernel code to use asynchronous memory copy capabilities,
21 * if present, and allows different HW DMA drivers to register as providing
22 * this capability.
23 *
24 * Due to the fact we are accelerating what is already a relatively fast
25 * operation, the code goes to great lengths to avoid additional overhead,
26 * such as locking.
27 *
28 * LOCKING:
29 *
30 * The subsystem keeps a global list of dma_device structs it is protected by a
31 * mutex, dma_list_mutex.
32 *
33 * A subsystem can get access to a channel by calling dmaengine_get() followed
34 * by dma_find_channel(), or if it has need for an exclusive channel it can call
35 * dma_request_channel(). Once a channel is allocated a reference is taken
36 * against its corresponding driver to disable removal.
37 *
38 * Each device has a channels list, which runs unlocked but is never modified
39 * once the device is registered, it's just setup by the driver.
40 *
41 * See Documentation/dmaengine.txt for more details
42 */
43
44#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
45
46#include <linux/platform_device.h>
47#include <linux/dma-mapping.h>
48#include <linux/init.h>
49#include <linux/module.h>
50#include <linux/mm.h>
51#include <linux/device.h>
52#include <linux/dmaengine.h>
53#include <linux/hardirq.h>
54#include <linux/spinlock.h>
55#include <linux/percpu.h>
56#include <linux/rcupdate.h>
57#include <linux/mutex.h>
58#include <linux/jiffies.h>
59#include <linux/rculist.h>
60#include <linux/idr.h>
61#include <linux/slab.h>
62#include <linux/acpi.h>
63#include <linux/acpi_dma.h>
64#include <linux/of_dma.h>
65#include <linux/mempool.h>
66
67static DEFINE_MUTEX(dma_list_mutex);
68static DEFINE_IDA(dma_ida);
69static LIST_HEAD(dma_device_list);
70static long dmaengine_ref_count;
71
72/* --- sysfs implementation --- */
73
74/**
75 * dev_to_dma_chan - convert a device pointer to the its sysfs container object
76 * @dev - device node
77 *
78 * Must be called under dma_list_mutex
79 */
80static struct dma_chan *dev_to_dma_chan(struct device *dev)
81{
82 struct dma_chan_dev *chan_dev;
83
84 chan_dev = container_of(dev, typeof(*chan_dev), device);
85 return chan_dev->chan;
86}
87
88static ssize_t memcpy_count_show(struct device *dev,
89 struct device_attribute *attr, char *buf)
90{
91 struct dma_chan *chan;
92 unsigned long count = 0;
93 int i;
94 int err;
95
96 mutex_lock(&dma_list_mutex);
97 chan = dev_to_dma_chan(dev);
98 if (chan) {
99 for_each_possible_cpu(i)
100 count += per_cpu_ptr(chan->local, i)->memcpy_count;
101 err = sprintf(buf, "%lu\n", count);
102 } else
103 err = -ENODEV;
104 mutex_unlock(&dma_list_mutex);
105
106 return err;
107}
108static DEVICE_ATTR_RO(memcpy_count);
109
110static ssize_t bytes_transferred_show(struct device *dev,
111 struct device_attribute *attr, char *buf)
112{
113 struct dma_chan *chan;
114 unsigned long count = 0;
115 int i;
116 int err;
117
118 mutex_lock(&dma_list_mutex);
119 chan = dev_to_dma_chan(dev);
120 if (chan) {
121 for_each_possible_cpu(i)
122 count += per_cpu_ptr(chan->local, i)->bytes_transferred;
123 err = sprintf(buf, "%lu\n", count);
124 } else
125 err = -ENODEV;
126 mutex_unlock(&dma_list_mutex);
127
128 return err;
129}
130static DEVICE_ATTR_RO(bytes_transferred);
131
132static ssize_t in_use_show(struct device *dev, struct device_attribute *attr,
133 char *buf)
134{
135 struct dma_chan *chan;
136 int err;
137
138 mutex_lock(&dma_list_mutex);
139 chan = dev_to_dma_chan(dev);
140 if (chan)
141 err = sprintf(buf, "%d\n", chan->client_count);
142 else
143 err = -ENODEV;
144 mutex_unlock(&dma_list_mutex);
145
146 return err;
147}
148static DEVICE_ATTR_RO(in_use);
149
150static struct attribute *dma_dev_attrs[] = {
151 &dev_attr_memcpy_count.attr,
152 &dev_attr_bytes_transferred.attr,
153 &dev_attr_in_use.attr,
154 NULL,
155};
156ATTRIBUTE_GROUPS(dma_dev);
157
158static void chan_dev_release(struct device *dev)
159{
160 struct dma_chan_dev *chan_dev;
161
162 chan_dev = container_of(dev, typeof(*chan_dev), device);
163 if (atomic_dec_and_test(chan_dev->idr_ref)) {
164 mutex_lock(&dma_list_mutex);
165 ida_remove(&dma_ida, chan_dev->dev_id);
166 mutex_unlock(&dma_list_mutex);
167 kfree(chan_dev->idr_ref);
168 }
169 kfree(chan_dev);
170}
171
172static struct class dma_devclass = {
173 .name = "dma",
174 .dev_groups = dma_dev_groups,
175 .dev_release = chan_dev_release,
176};
177
178/* --- client and device registration --- */
179
180#define dma_device_satisfies_mask(device, mask) \
181 __dma_device_satisfies_mask((device), &(mask))
182static int
183__dma_device_satisfies_mask(struct dma_device *device,
184 const dma_cap_mask_t *want)
185{
186 dma_cap_mask_t has;
187
188 bitmap_and(has.bits, want->bits, device->cap_mask.bits,
189 DMA_TX_TYPE_END);
190 return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END);
191}
192
193static struct module *dma_chan_to_owner(struct dma_chan *chan)
194{
195 return chan->device->dev->driver->owner;
196}
197
198/**
199 * balance_ref_count - catch up the channel reference count
200 * @chan - channel to balance ->client_count versus dmaengine_ref_count
201 *
202 * balance_ref_count must be called under dma_list_mutex
203 */
204static void balance_ref_count(struct dma_chan *chan)
205{
206 struct module *owner = dma_chan_to_owner(chan);
207
208 while (chan->client_count < dmaengine_ref_count) {
209 __module_get(owner);
210 chan->client_count++;
211 }
212}
213
214/**
215 * dma_chan_get - try to grab a dma channel's parent driver module
216 * @chan - channel to grab
217 *
218 * Must be called under dma_list_mutex
219 */
220static int dma_chan_get(struct dma_chan *chan)
221{
222 struct module *owner = dma_chan_to_owner(chan);
223 int ret;
224
225 /* The channel is already in use, update client count */
226 if (chan->client_count) {
227 __module_get(owner);
228 goto out;
229 }
230
231 if (!try_module_get(owner))
232 return -ENODEV;
233
234 /* allocate upon first client reference */
235 if (chan->device->device_alloc_chan_resources) {
236 ret = chan->device->device_alloc_chan_resources(chan);
237 if (ret < 0)
238 goto err_out;
239 }
240
241 if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
242 balance_ref_count(chan);
243
244out:
245 chan->client_count++;
246 return 0;
247
248err_out:
249 module_put(owner);
250 return ret;
251}
252
253/**
254 * dma_chan_put - drop a reference to a dma channel's parent driver module
255 * @chan - channel to release
256 *
257 * Must be called under dma_list_mutex
258 */
259static void dma_chan_put(struct dma_chan *chan)
260{
261 /* This channel is not in use, bail out */
262 if (!chan->client_count)
263 return;
264
265 chan->client_count--;
266 module_put(dma_chan_to_owner(chan));
267
268 /* This channel is not in use anymore, free it */
269 if (!chan->client_count && chan->device->device_free_chan_resources) {
270 /* Make sure all operations have completed */
271 dmaengine_synchronize(chan);
272 chan->device->device_free_chan_resources(chan);
273 }
274
275 /* If the channel is used via a DMA request router, free the mapping */
276 if (chan->router && chan->router->route_free) {
277 chan->router->route_free(chan->router->dev, chan->route_data);
278 chan->router = NULL;
279 chan->route_data = NULL;
280 }
281}
282
283enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
284{
285 enum dma_status status;
286 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
287
288 dma_async_issue_pending(chan);
289 do {
290 status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
291 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
292 dev_err(chan->device->dev, "%s: timeout!\n", __func__);
293 return DMA_ERROR;
294 }
295 if (status != DMA_IN_PROGRESS)
296 break;
297 cpu_relax();
298 } while (1);
299
300 return status;
301}
302EXPORT_SYMBOL(dma_sync_wait);
303
304/**
305 * dma_cap_mask_all - enable iteration over all operation types
306 */
307static dma_cap_mask_t dma_cap_mask_all;
308
309/**
310 * dma_chan_tbl_ent - tracks channel allocations per core/operation
311 * @chan - associated channel for this entry
312 */
313struct dma_chan_tbl_ent {
314 struct dma_chan *chan;
315};
316
317/**
318 * channel_table - percpu lookup table for memory-to-memory offload providers
319 */
320static struct dma_chan_tbl_ent __percpu *channel_table[DMA_TX_TYPE_END];
321
322static int __init dma_channel_table_init(void)
323{
324 enum dma_transaction_type cap;
325 int err = 0;
326
327 bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END);
328
329 /* 'interrupt', 'private', and 'slave' are channel capabilities,
330 * but are not associated with an operation so they do not need
331 * an entry in the channel_table
332 */
333 clear_bit(DMA_INTERRUPT, dma_cap_mask_all.bits);
334 clear_bit(DMA_PRIVATE, dma_cap_mask_all.bits);
335 clear_bit(DMA_SLAVE, dma_cap_mask_all.bits);
336
337 for_each_dma_cap_mask(cap, dma_cap_mask_all) {
338 channel_table[cap] = alloc_percpu(struct dma_chan_tbl_ent);
339 if (!channel_table[cap]) {
340 err = -ENOMEM;
341 break;
342 }
343 }
344
345 if (err) {
346 pr_err("initialization failure\n");
347 for_each_dma_cap_mask(cap, dma_cap_mask_all)
348 free_percpu(channel_table[cap]);
349 }
350
351 return err;
352}
353arch_initcall(dma_channel_table_init);
354
355/**
356 * dma_find_channel - find a channel to carry out the operation
357 * @tx_type: transaction type
358 */
359struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
360{
361 return this_cpu_read(channel_table[tx_type]->chan);
362}
363EXPORT_SYMBOL(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
475int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps)
476{
477 struct dma_device *device;
478
479 if (!chan || !caps)
480 return -EINVAL;
481
482 device = chan->device;
483
484 /* check if the channel supports slave transactions */
485 if (!(test_bit(DMA_SLAVE, device->cap_mask.bits) ||
486 test_bit(DMA_CYCLIC, device->cap_mask.bits)))
487 return -ENXIO;
488
489 /*
490 * Check whether it reports it uses the generic slave
491 * capabilities, if not, that means it doesn't support any
492 * kind of slave capabilities reporting.
493 */
494 if (!device->directions)
495 return -ENXIO;
496
497 caps->src_addr_widths = device->src_addr_widths;
498 caps->dst_addr_widths = device->dst_addr_widths;
499 caps->directions = device->directions;
500 caps->max_burst = device->max_burst;
501 caps->residue_granularity = device->residue_granularity;
502 caps->descriptor_reuse = device->descriptor_reuse;
503
504 /*
505 * Some devices implement only pause (e.g. to get residuum) but no
506 * resume. However cmd_pause is advertised as pause AND resume.
507 */
508 caps->cmd_pause = !!(device->device_pause && device->device_resume);
509 caps->cmd_terminate = !!device->device_terminate_all;
510
511 return 0;
512}
513EXPORT_SYMBOL_GPL(dma_get_slave_caps);
514
515static struct dma_chan *private_candidate(const dma_cap_mask_t *mask,
516 struct dma_device *dev,
517 dma_filter_fn fn, void *fn_param)
518{
519 struct dma_chan *chan;
520
521 if (mask && !__dma_device_satisfies_mask(dev, mask)) {
522 dev_dbg(dev->dev, "%s: wrong capabilities\n", __func__);
523 return NULL;
524 }
525 /* devices with multiple channels need special handling as we need to
526 * ensure that all channels are either private or public.
527 */
528 if (dev->chancnt > 1 && !dma_has_cap(DMA_PRIVATE, dev->cap_mask))
529 list_for_each_entry(chan, &dev->channels, device_node) {
530 /* some channels are already publicly allocated */
531 if (chan->client_count)
532 return NULL;
533 }
534
535 list_for_each_entry(chan, &dev->channels, device_node) {
536 if (chan->client_count) {
537 dev_dbg(dev->dev, "%s: %s busy\n",
538 __func__, dma_chan_name(chan));
539 continue;
540 }
541 if (fn && !fn(chan, fn_param)) {
542 dev_dbg(dev->dev, "%s: %s filter said false\n",
543 __func__, dma_chan_name(chan));
544 continue;
545 }
546 return chan;
547 }
548
549 return NULL;
550}
551
552static struct dma_chan *find_candidate(struct dma_device *device,
553 const dma_cap_mask_t *mask,
554 dma_filter_fn fn, void *fn_param)
555{
556 struct dma_chan *chan = private_candidate(mask, device, fn, fn_param);
557 int err;
558
559 if (chan) {
560 /* Found a suitable channel, try to grab, prep, and return it.
561 * We first set DMA_PRIVATE to disable balance_ref_count as this
562 * channel will not be published in the general-purpose
563 * allocator
564 */
565 dma_cap_set(DMA_PRIVATE, device->cap_mask);
566 device->privatecnt++;
567 err = dma_chan_get(chan);
568
569 if (err) {
570 if (err == -ENODEV) {
571 dev_dbg(device->dev, "%s: %s module removed\n",
572 __func__, dma_chan_name(chan));
573 list_del_rcu(&device->global_node);
574 } else
575 dev_dbg(device->dev,
576 "%s: failed to get %s: (%d)\n",
577 __func__, dma_chan_name(chan), err);
578
579 if (--device->privatecnt == 0)
580 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
581
582 chan = ERR_PTR(err);
583 }
584 }
585
586 return chan ? chan : ERR_PTR(-EPROBE_DEFER);
587}
588
589/**
590 * dma_get_slave_channel - try to get specific channel exclusively
591 * @chan: target channel
592 */
593struct dma_chan *dma_get_slave_channel(struct dma_chan *chan)
594{
595 int err = -EBUSY;
596
597 /* lock against __dma_request_channel */
598 mutex_lock(&dma_list_mutex);
599
600 if (chan->client_count == 0) {
601 struct dma_device *device = chan->device;
602
603 dma_cap_set(DMA_PRIVATE, device->cap_mask);
604 device->privatecnt++;
605 err = dma_chan_get(chan);
606 if (err) {
607 dev_dbg(chan->device->dev,
608 "%s: failed to get %s: (%d)\n",
609 __func__, dma_chan_name(chan), err);
610 chan = NULL;
611 if (--device->privatecnt == 0)
612 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
613 }
614 } else
615 chan = NULL;
616
617 mutex_unlock(&dma_list_mutex);
618
619
620 return chan;
621}
622EXPORT_SYMBOL_GPL(dma_get_slave_channel);
623
624struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)
625{
626 dma_cap_mask_t mask;
627 struct dma_chan *chan;
628
629 dma_cap_zero(mask);
630 dma_cap_set(DMA_SLAVE, mask);
631
632 /* lock against __dma_request_channel */
633 mutex_lock(&dma_list_mutex);
634
635 chan = find_candidate(device, &mask, NULL, NULL);
636
637 mutex_unlock(&dma_list_mutex);
638
639 return IS_ERR(chan) ? NULL : chan;
640}
641EXPORT_SYMBOL_GPL(dma_get_any_slave_channel);
642
643/**
644 * __dma_request_channel - try to allocate an exclusive channel
645 * @mask: capabilities that the channel must satisfy
646 * @fn: optional callback to disposition available channels
647 * @fn_param: opaque parameter to pass to dma_filter_fn
648 *
649 * Returns pointer to appropriate DMA channel on success or NULL.
650 */
651struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
652 dma_filter_fn fn, void *fn_param)
653{
654 struct dma_device *device, *_d;
655 struct dma_chan *chan = NULL;
656
657 /* Find a channel */
658 mutex_lock(&dma_list_mutex);
659 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
660 chan = find_candidate(device, mask, fn, fn_param);
661 if (!IS_ERR(chan))
662 break;
663
664 chan = NULL;
665 }
666 mutex_unlock(&dma_list_mutex);
667
668 pr_debug("%s: %s (%s)\n",
669 __func__,
670 chan ? "success" : "fail",
671 chan ? dma_chan_name(chan) : NULL);
672
673 return chan;
674}
675EXPORT_SYMBOL_GPL(__dma_request_channel);
676
677static const struct dma_slave_map *dma_filter_match(struct dma_device *device,
678 const char *name,
679 struct device *dev)
680{
681 int i;
682
683 if (!device->filter.mapcnt)
684 return NULL;
685
686 for (i = 0; i < device->filter.mapcnt; i++) {
687 const struct dma_slave_map *map = &device->filter.map[i];
688
689 if (!strcmp(map->devname, dev_name(dev)) &&
690 !strcmp(map->slave, name))
691 return map;
692 }
693
694 return NULL;
695}
696
697/**
698 * dma_request_chan - try to allocate an exclusive slave channel
699 * @dev: pointer to client device structure
700 * @name: slave channel name
701 *
702 * Returns pointer to appropriate DMA channel on success or an error pointer.
703 */
704struct dma_chan *dma_request_chan(struct device *dev, const char *name)
705{
706 struct dma_device *d, *_d;
707 struct dma_chan *chan = NULL;
708
709 /* If device-tree is present get slave info from here */
710 if (dev->of_node)
711 chan = of_dma_request_slave_channel(dev->of_node, name);
712
713 /* If device was enumerated by ACPI get slave info from here */
714 if (has_acpi_companion(dev) && !chan)
715 chan = acpi_dma_request_slave_chan_by_name(dev, name);
716
717 if (chan) {
718 /* Valid channel found or requester need to be deferred */
719 if (!IS_ERR(chan) || PTR_ERR(chan) == -EPROBE_DEFER)
720 return chan;
721 }
722
723 /* Try to find the channel via the DMA filter map(s) */
724 mutex_lock(&dma_list_mutex);
725 list_for_each_entry_safe(d, _d, &dma_device_list, global_node) {
726 dma_cap_mask_t mask;
727 const struct dma_slave_map *map = dma_filter_match(d, name, dev);
728
729 if (!map)
730 continue;
731
732 dma_cap_zero(mask);
733 dma_cap_set(DMA_SLAVE, mask);
734
735 chan = find_candidate(d, &mask, d->filter.fn, map->param);
736 if (!IS_ERR(chan))
737 break;
738 }
739 mutex_unlock(&dma_list_mutex);
740
741 return chan ? chan : ERR_PTR(-EPROBE_DEFER);
742}
743EXPORT_SYMBOL_GPL(dma_request_chan);
744
745/**
746 * dma_request_slave_channel - try to allocate an exclusive slave channel
747 * @dev: pointer to client device structure
748 * @name: slave channel name
749 *
750 * Returns pointer to appropriate DMA channel on success or NULL.
751 */
752struct dma_chan *dma_request_slave_channel(struct device *dev,
753 const char *name)
754{
755 struct dma_chan *ch = dma_request_chan(dev, name);
756 if (IS_ERR(ch))
757 return NULL;
758
759 return ch;
760}
761EXPORT_SYMBOL_GPL(dma_request_slave_channel);
762
763/**
764 * dma_request_chan_by_mask - allocate a channel satisfying certain capabilities
765 * @mask: capabilities that the channel must satisfy
766 *
767 * Returns pointer to appropriate DMA channel on success or an error pointer.
768 */
769struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask)
770{
771 struct dma_chan *chan;
772
773 if (!mask)
774 return ERR_PTR(-ENODEV);
775
776 chan = __dma_request_channel(mask, NULL, NULL);
777 if (!chan)
778 chan = ERR_PTR(-ENODEV);
779
780 return chan;
781}
782EXPORT_SYMBOL_GPL(dma_request_chan_by_mask);
783
784void dma_release_channel(struct dma_chan *chan)
785{
786 mutex_lock(&dma_list_mutex);
787 WARN_ONCE(chan->client_count != 1,
788 "chan reference count %d != 1\n", chan->client_count);
789 dma_chan_put(chan);
790 /* drop PRIVATE cap enabled by __dma_request_channel() */
791 if (--chan->device->privatecnt == 0)
792 dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
793 mutex_unlock(&dma_list_mutex);
794}
795EXPORT_SYMBOL_GPL(dma_release_channel);
796
797/**
798 * dmaengine_get - register interest in dma_channels
799 */
800void dmaengine_get(void)
801{
802 struct dma_device *device, *_d;
803 struct dma_chan *chan;
804 int err;
805
806 mutex_lock(&dma_list_mutex);
807 dmaengine_ref_count++;
808
809 /* try to grab channels */
810 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
811 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
812 continue;
813 list_for_each_entry(chan, &device->channels, device_node) {
814 err = dma_chan_get(chan);
815 if (err == -ENODEV) {
816 /* module removed before we could use it */
817 list_del_rcu(&device->global_node);
818 break;
819 } else if (err)
820 dev_dbg(chan->device->dev,
821 "%s: failed to get %s: (%d)\n",
822 __func__, dma_chan_name(chan), err);
823 }
824 }
825
826 /* if this is the first reference and there were channels
827 * waiting we need to rebalance to get those channels
828 * incorporated into the channel table
829 */
830 if (dmaengine_ref_count == 1)
831 dma_channel_rebalance();
832 mutex_unlock(&dma_list_mutex);
833}
834EXPORT_SYMBOL(dmaengine_get);
835
836/**
837 * dmaengine_put - let dma drivers be removed when ref_count == 0
838 */
839void dmaengine_put(void)
840{
841 struct dma_device *device;
842 struct dma_chan *chan;
843
844 mutex_lock(&dma_list_mutex);
845 dmaengine_ref_count--;
846 BUG_ON(dmaengine_ref_count < 0);
847 /* drop channel references */
848 list_for_each_entry(device, &dma_device_list, global_node) {
849 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
850 continue;
851 list_for_each_entry(chan, &device->channels, device_node)
852 dma_chan_put(chan);
853 }
854 mutex_unlock(&dma_list_mutex);
855}
856EXPORT_SYMBOL(dmaengine_put);
857
858static bool device_has_all_tx_types(struct dma_device *device)
859{
860 /* A device that satisfies this test has channels that will never cause
861 * an async_tx channel switch event as all possible operation types can
862 * be handled.
863 */
864 #ifdef CONFIG_ASYNC_TX_DMA
865 if (!dma_has_cap(DMA_INTERRUPT, device->cap_mask))
866 return false;
867 #endif
868
869 #if IS_ENABLED(CONFIG_ASYNC_MEMCPY)
870 if (!dma_has_cap(DMA_MEMCPY, device->cap_mask))
871 return false;
872 #endif
873
874 #if IS_ENABLED(CONFIG_ASYNC_XOR)
875 if (!dma_has_cap(DMA_XOR, device->cap_mask))
876 return false;
877
878 #ifndef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
879 if (!dma_has_cap(DMA_XOR_VAL, device->cap_mask))
880 return false;
881 #endif
882 #endif
883
884 #if IS_ENABLED(CONFIG_ASYNC_PQ)
885 if (!dma_has_cap(DMA_PQ, device->cap_mask))
886 return false;
887
888 #ifndef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
889 if (!dma_has_cap(DMA_PQ_VAL, device->cap_mask))
890 return false;
891 #endif
892 #endif
893
894 return true;
895}
896
897static int get_dma_id(struct dma_device *device)
898{
899 int rc;
900
901 do {
902 if (!ida_pre_get(&dma_ida, GFP_KERNEL))
903 return -ENOMEM;
904 mutex_lock(&dma_list_mutex);
905 rc = ida_get_new(&dma_ida, &device->dev_id);
906 mutex_unlock(&dma_list_mutex);
907 } while (rc == -EAGAIN);
908
909 return rc;
910}
911
912/**
913 * dma_async_device_register - registers DMA devices found
914 * @device: &dma_device
915 */
916int dma_async_device_register(struct dma_device *device)
917{
918 int chancnt = 0, rc;
919 struct dma_chan* chan;
920 atomic_t *idr_ref;
921
922 if (!device)
923 return -ENODEV;
924
925 /* validate device routines */
926 if (!device->dev) {
927 pr_err("DMAdevice must have dev\n");
928 return -EIO;
929 }
930
931 if (dma_has_cap(DMA_MEMCPY, device->cap_mask) && !device->device_prep_dma_memcpy) {
932 dev_err(device->dev,
933 "Device claims capability %s, but op is not defined\n",
934 "DMA_MEMCPY");
935 return -EIO;
936 }
937
938 if (dma_has_cap(DMA_XOR, device->cap_mask) && !device->device_prep_dma_xor) {
939 dev_err(device->dev,
940 "Device claims capability %s, but op is not defined\n",
941 "DMA_XOR");
942 return -EIO;
943 }
944
945 if (dma_has_cap(DMA_XOR_VAL, device->cap_mask) && !device->device_prep_dma_xor_val) {
946 dev_err(device->dev,
947 "Device claims capability %s, but op is not defined\n",
948 "DMA_XOR_VAL");
949 return -EIO;
950 }
951
952 if (dma_has_cap(DMA_PQ, device->cap_mask) && !device->device_prep_dma_pq) {
953 dev_err(device->dev,
954 "Device claims capability %s, but op is not defined\n",
955 "DMA_PQ");
956 return -EIO;
957 }
958
959 if (dma_has_cap(DMA_PQ_VAL, device->cap_mask) && !device->device_prep_dma_pq_val) {
960 dev_err(device->dev,
961 "Device claims capability %s, but op is not defined\n",
962 "DMA_PQ_VAL");
963 return -EIO;
964 }
965
966 if (dma_has_cap(DMA_MEMSET, device->cap_mask) && !device->device_prep_dma_memset) {
967 dev_err(device->dev,
968 "Device claims capability %s, but op is not defined\n",
969 "DMA_MEMSET");
970 return -EIO;
971 }
972
973 if (dma_has_cap(DMA_INTERRUPT, device->cap_mask) && !device->device_prep_dma_interrupt) {
974 dev_err(device->dev,
975 "Device claims capability %s, but op is not defined\n",
976 "DMA_INTERRUPT");
977 return -EIO;
978 }
979
980 if (dma_has_cap(DMA_CYCLIC, device->cap_mask) && !device->device_prep_dma_cyclic) {
981 dev_err(device->dev,
982 "Device claims capability %s, but op is not defined\n",
983 "DMA_CYCLIC");
984 return -EIO;
985 }
986
987 if (dma_has_cap(DMA_INTERLEAVE, device->cap_mask) && !device->device_prep_interleaved_dma) {
988 dev_err(device->dev,
989 "Device claims capability %s, but op is not defined\n",
990 "DMA_INTERLEAVE");
991 return -EIO;
992 }
993
994
995 if (!device->device_tx_status) {
996 dev_err(device->dev, "Device tx_status is not defined\n");
997 return -EIO;
998 }
999
1000
1001 if (!device->device_issue_pending) {
1002 dev_err(device->dev, "Device issue_pending is not defined\n");
1003 return -EIO;
1004 }
1005
1006 /* note: this only matters in the
1007 * CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH=n case
1008 */
1009 if (device_has_all_tx_types(device))
1010 dma_cap_set(DMA_ASYNC_TX, device->cap_mask);
1011
1012 idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL);
1013 if (!idr_ref)
1014 return -ENOMEM;
1015 rc = get_dma_id(device);
1016 if (rc != 0) {
1017 kfree(idr_ref);
1018 return rc;
1019 }
1020
1021 atomic_set(idr_ref, 0);
1022
1023 /* represent channels in sysfs. Probably want devs too */
1024 list_for_each_entry(chan, &device->channels, device_node) {
1025 rc = -ENOMEM;
1026 chan->local = alloc_percpu(typeof(*chan->local));
1027 if (chan->local == NULL)
1028 goto err_out;
1029 chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
1030 if (chan->dev == NULL) {
1031 free_percpu(chan->local);
1032 chan->local = NULL;
1033 goto err_out;
1034 }
1035
1036 chan->chan_id = chancnt++;
1037 chan->dev->device.class = &dma_devclass;
1038 chan->dev->device.parent = device->dev;
1039 chan->dev->chan = chan;
1040 chan->dev->idr_ref = idr_ref;
1041 chan->dev->dev_id = device->dev_id;
1042 atomic_inc(idr_ref);
1043 dev_set_name(&chan->dev->device, "dma%dchan%d",
1044 device->dev_id, chan->chan_id);
1045
1046 rc = device_register(&chan->dev->device);
1047 if (rc) {
1048 free_percpu(chan->local);
1049 chan->local = NULL;
1050 kfree(chan->dev);
1051 atomic_dec(idr_ref);
1052 goto err_out;
1053 }
1054 chan->client_count = 0;
1055 }
1056
1057 if (!chancnt) {
1058 dev_err(device->dev, "%s: device has no channels!\n", __func__);
1059 rc = -ENODEV;
1060 goto err_out;
1061 }
1062
1063 device->chancnt = chancnt;
1064
1065 mutex_lock(&dma_list_mutex);
1066 /* take references on public channels */
1067 if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
1068 list_for_each_entry(chan, &device->channels, device_node) {
1069 /* if clients are already waiting for channels we need
1070 * to take references on their behalf
1071 */
1072 if (dma_chan_get(chan) == -ENODEV) {
1073 /* note we can only get here for the first
1074 * channel as the remaining channels are
1075 * guaranteed to get a reference
1076 */
1077 rc = -ENODEV;
1078 mutex_unlock(&dma_list_mutex);
1079 goto err_out;
1080 }
1081 }
1082 list_add_tail_rcu(&device->global_node, &dma_device_list);
1083 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
1084 device->privatecnt++; /* Always private */
1085 dma_channel_rebalance();
1086 mutex_unlock(&dma_list_mutex);
1087
1088 return 0;
1089
1090err_out:
1091 /* if we never registered a channel just release the idr */
1092 if (atomic_read(idr_ref) == 0) {
1093 mutex_lock(&dma_list_mutex);
1094 ida_remove(&dma_ida, device->dev_id);
1095 mutex_unlock(&dma_list_mutex);
1096 kfree(idr_ref);
1097 return rc;
1098 }
1099
1100 list_for_each_entry(chan, &device->channels, device_node) {
1101 if (chan->local == NULL)
1102 continue;
1103 mutex_lock(&dma_list_mutex);
1104 chan->dev->chan = NULL;
1105 mutex_unlock(&dma_list_mutex);
1106 device_unregister(&chan->dev->device);
1107 free_percpu(chan->local);
1108 }
1109 return rc;
1110}
1111EXPORT_SYMBOL(dma_async_device_register);
1112
1113/**
1114 * dma_async_device_unregister - unregister a DMA device
1115 * @device: &dma_device
1116 *
1117 * This routine is called by dma driver exit routines, dmaengine holds module
1118 * references to prevent it being called while channels are in use.
1119 */
1120void dma_async_device_unregister(struct dma_device *device)
1121{
1122 struct dma_chan *chan;
1123
1124 mutex_lock(&dma_list_mutex);
1125 list_del_rcu(&device->global_node);
1126 dma_channel_rebalance();
1127 mutex_unlock(&dma_list_mutex);
1128
1129 list_for_each_entry(chan, &device->channels, device_node) {
1130 WARN_ONCE(chan->client_count,
1131 "%s called while %d clients hold a reference\n",
1132 __func__, chan->client_count);
1133 mutex_lock(&dma_list_mutex);
1134 chan->dev->chan = NULL;
1135 mutex_unlock(&dma_list_mutex);
1136 device_unregister(&chan->dev->device);
1137 free_percpu(chan->local);
1138 }
1139}
1140EXPORT_SYMBOL(dma_async_device_unregister);
1141
1142struct dmaengine_unmap_pool {
1143 struct kmem_cache *cache;
1144 const char *name;
1145 mempool_t *pool;
1146 size_t size;
1147};
1148
1149#define __UNMAP_POOL(x) { .size = x, .name = "dmaengine-unmap-" __stringify(x) }
1150static struct dmaengine_unmap_pool unmap_pool[] = {
1151 __UNMAP_POOL(2),
1152 #if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
1153 __UNMAP_POOL(16),
1154 __UNMAP_POOL(128),
1155 __UNMAP_POOL(256),
1156 #endif
1157};
1158
1159static struct dmaengine_unmap_pool *__get_unmap_pool(int nr)
1160{
1161 int order = get_count_order(nr);
1162
1163 switch (order) {
1164 case 0 ... 1:
1165 return &unmap_pool[0];
1166#if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
1167 case 2 ... 4:
1168 return &unmap_pool[1];
1169 case 5 ... 7:
1170 return &unmap_pool[2];
1171 case 8:
1172 return &unmap_pool[3];
1173#endif
1174 default:
1175 BUG();
1176 return NULL;
1177 }
1178}
1179
1180static void dmaengine_unmap(struct kref *kref)
1181{
1182 struct dmaengine_unmap_data *unmap = container_of(kref, typeof(*unmap), kref);
1183 struct device *dev = unmap->dev;
1184 int cnt, i;
1185
1186 cnt = unmap->to_cnt;
1187 for (i = 0; i < cnt; i++)
1188 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1189 DMA_TO_DEVICE);
1190 cnt += unmap->from_cnt;
1191 for (; i < cnt; i++)
1192 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1193 DMA_FROM_DEVICE);
1194 cnt += unmap->bidi_cnt;
1195 for (; i < cnt; i++) {
1196 if (unmap->addr[i] == 0)
1197 continue;
1198 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1199 DMA_BIDIRECTIONAL);
1200 }
1201 cnt = unmap->map_cnt;
1202 mempool_free(unmap, __get_unmap_pool(cnt)->pool);
1203}
1204
1205void dmaengine_unmap_put(struct dmaengine_unmap_data *unmap)
1206{
1207 if (unmap)
1208 kref_put(&unmap->kref, dmaengine_unmap);
1209}
1210EXPORT_SYMBOL_GPL(dmaengine_unmap_put);
1211
1212static void dmaengine_destroy_unmap_pool(void)
1213{
1214 int i;
1215
1216 for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
1217 struct dmaengine_unmap_pool *p = &unmap_pool[i];
1218
1219 mempool_destroy(p->pool);
1220 p->pool = NULL;
1221 kmem_cache_destroy(p->cache);
1222 p->cache = NULL;
1223 }
1224}
1225
1226static int __init dmaengine_init_unmap_pool(void)
1227{
1228 int i;
1229
1230 for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
1231 struct dmaengine_unmap_pool *p = &unmap_pool[i];
1232 size_t size;
1233
1234 size = sizeof(struct dmaengine_unmap_data) +
1235 sizeof(dma_addr_t) * p->size;
1236
1237 p->cache = kmem_cache_create(p->name, size, 0,
1238 SLAB_HWCACHE_ALIGN, NULL);
1239 if (!p->cache)
1240 break;
1241 p->pool = mempool_create_slab_pool(1, p->cache);
1242 if (!p->pool)
1243 break;
1244 }
1245
1246 if (i == ARRAY_SIZE(unmap_pool))
1247 return 0;
1248
1249 dmaengine_destroy_unmap_pool();
1250 return -ENOMEM;
1251}
1252
1253struct dmaengine_unmap_data *
1254dmaengine_get_unmap_data(struct device *dev, int nr, gfp_t flags)
1255{
1256 struct dmaengine_unmap_data *unmap;
1257
1258 unmap = mempool_alloc(__get_unmap_pool(nr)->pool, flags);
1259 if (!unmap)
1260 return NULL;
1261
1262 memset(unmap, 0, sizeof(*unmap));
1263 kref_init(&unmap->kref);
1264 unmap->dev = dev;
1265 unmap->map_cnt = nr;
1266
1267 return unmap;
1268}
1269EXPORT_SYMBOL(dmaengine_get_unmap_data);
1270
1271void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
1272 struct dma_chan *chan)
1273{
1274 tx->chan = chan;
1275 #ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
1276 spin_lock_init(&tx->lock);
1277 #endif
1278}
1279EXPORT_SYMBOL(dma_async_tx_descriptor_init);
1280
1281/* dma_wait_for_async_tx - spin wait for a transaction to complete
1282 * @tx: in-flight transaction to wait on
1283 */
1284enum dma_status
1285dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
1286{
1287 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
1288
1289 if (!tx)
1290 return DMA_COMPLETE;
1291
1292 while (tx->cookie == -EBUSY) {
1293 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
1294 dev_err(tx->chan->device->dev,
1295 "%s timeout waiting for descriptor submission\n",
1296 __func__);
1297 return DMA_ERROR;
1298 }
1299 cpu_relax();
1300 }
1301 return dma_sync_wait(tx->chan, tx->cookie);
1302}
1303EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
1304
1305/* dma_run_dependencies - helper routine for dma drivers to process
1306 * (start) dependent operations on their target channel
1307 * @tx: transaction with dependencies
1308 */
1309void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
1310{
1311 struct dma_async_tx_descriptor *dep = txd_next(tx);
1312 struct dma_async_tx_descriptor *dep_next;
1313 struct dma_chan *chan;
1314
1315 if (!dep)
1316 return;
1317
1318 /* we'll submit tx->next now, so clear the link */
1319 txd_clear_next(tx);
1320 chan = dep->chan;
1321
1322 /* keep submitting up until a channel switch is detected
1323 * in that case we will be called again as a result of
1324 * processing the interrupt from async_tx_channel_switch
1325 */
1326 for (; dep; dep = dep_next) {
1327 txd_lock(dep);
1328 txd_clear_parent(dep);
1329 dep_next = txd_next(dep);
1330 if (dep_next && dep_next->chan == chan)
1331 txd_clear_next(dep); /* ->next will be submitted */
1332 else
1333 dep_next = NULL; /* submit current dep and terminate */
1334 txd_unlock(dep);
1335
1336 dep->tx_submit(dep);
1337 }
1338
1339 chan->device->device_issue_pending(chan);
1340}
1341EXPORT_SYMBOL_GPL(dma_run_dependencies);
1342
1343static int __init dma_bus_init(void)
1344{
1345 int err = dmaengine_init_unmap_pool();
1346
1347 if (err)
1348 return err;
1349 return class_register(&dma_devclass);
1350}
1351arch_initcall(dma_bus_init);
1352
1353