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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
4 */
5
6/*
7 * This code implements the DMA subsystem. It provides a HW-neutral interface
8 * for other kernel code to use asynchronous memory copy capabilities,
9 * if present, and allows different HW DMA drivers to register as providing
10 * this capability.
11 *
12 * Due to the fact we are accelerating what is already a relatively fast
13 * operation, the code goes to great lengths to avoid additional overhead,
14 * such as locking.
15 *
16 * LOCKING:
17 *
18 * The subsystem keeps a global list of dma_device structs it is protected by a
19 * mutex, dma_list_mutex.
20 *
21 * A subsystem can get access to a channel by calling dmaengine_get() followed
22 * by dma_find_channel(), or if it has need for an exclusive channel it can call
23 * dma_request_channel(). Once a channel is allocated a reference is taken
24 * against its corresponding driver to disable removal.
25 *
26 * Each device has a channels list, which runs unlocked but is never modified
27 * once the device is registered, it's just setup by the driver.
28 *
29 * See Documentation/driver-api/dmaengine for more details
30 */
31
32#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33
34#include <linux/platform_device.h>
35#include <linux/dma-mapping.h>
36#include <linux/init.h>
37#include <linux/module.h>
38#include <linux/mm.h>
39#include <linux/device.h>
40#include <linux/dmaengine.h>
41#include <linux/hardirq.h>
42#include <linux/spinlock.h>
43#include <linux/percpu.h>
44#include <linux/rcupdate.h>
45#include <linux/mutex.h>
46#include <linux/jiffies.h>
47#include <linux/rculist.h>
48#include <linux/idr.h>
49#include <linux/slab.h>
50#include <linux/acpi.h>
51#include <linux/acpi_dma.h>
52#include <linux/of_dma.h>
53#include <linux/mempool.h>
54#include <linux/numa.h>
55
56#include "dmaengine.h"
57
58static DEFINE_MUTEX(dma_list_mutex);
59static DEFINE_IDA(dma_ida);
60static LIST_HEAD(dma_device_list);
61static long dmaengine_ref_count;
62
63/* --- debugfs implementation --- */
64#ifdef CONFIG_DEBUG_FS
65#include <linux/debugfs.h>
66
67static struct dentry *rootdir;
68
69static void dmaengine_debug_register(struct dma_device *dma_dev)
70{
71 dma_dev->dbg_dev_root = debugfs_create_dir(dev_name(dma_dev->dev),
72 rootdir);
73 if (IS_ERR(dma_dev->dbg_dev_root))
74 dma_dev->dbg_dev_root = NULL;
75}
76
77static void dmaengine_debug_unregister(struct dma_device *dma_dev)
78{
79 debugfs_remove_recursive(dma_dev->dbg_dev_root);
80 dma_dev->dbg_dev_root = NULL;
81}
82
83static void dmaengine_dbg_summary_show(struct seq_file *s,
84 struct dma_device *dma_dev)
85{
86 struct dma_chan *chan;
87
88 list_for_each_entry(chan, &dma_dev->channels, device_node) {
89 if (chan->client_count) {
90 seq_printf(s, " %-13s| %s", dma_chan_name(chan),
91 chan->dbg_client_name ?: "in-use");
92
93 if (chan->router)
94 seq_printf(s, " (via router: %s)\n",
95 dev_name(chan->router->dev));
96 else
97 seq_puts(s, "\n");
98 }
99 }
100}
101
102static int dmaengine_summary_show(struct seq_file *s, void *data)
103{
104 struct dma_device *dma_dev = NULL;
105
106 mutex_lock(&dma_list_mutex);
107 list_for_each_entry(dma_dev, &dma_device_list, global_node) {
108 seq_printf(s, "dma%d (%s): number of channels: %u\n",
109 dma_dev->dev_id, dev_name(dma_dev->dev),
110 dma_dev->chancnt);
111
112 if (dma_dev->dbg_summary_show)
113 dma_dev->dbg_summary_show(s, dma_dev);
114 else
115 dmaengine_dbg_summary_show(s, dma_dev);
116
117 if (!list_is_last(&dma_dev->global_node, &dma_device_list))
118 seq_puts(s, "\n");
119 }
120 mutex_unlock(&dma_list_mutex);
121
122 return 0;
123}
124DEFINE_SHOW_ATTRIBUTE(dmaengine_summary);
125
126static void __init dmaengine_debugfs_init(void)
127{
128 rootdir = debugfs_create_dir("dmaengine", NULL);
129
130 /* /sys/kernel/debug/dmaengine/summary */
131 debugfs_create_file("summary", 0444, rootdir, NULL,
132 &dmaengine_summary_fops);
133}
134#else
135static inline void dmaengine_debugfs_init(void) { }
136static inline int dmaengine_debug_register(struct dma_device *dma_dev)
137{
138 return 0;
139}
140
141static inline void dmaengine_debug_unregister(struct dma_device *dma_dev) { }
142#endif /* DEBUG_FS */
143
144/* --- sysfs implementation --- */
145
146#define DMA_SLAVE_NAME "slave"
147
148/**
149 * dev_to_dma_chan - convert a device pointer to its sysfs container object
150 * @dev: device node
151 *
152 * Must be called under dma_list_mutex.
153 */
154static struct dma_chan *dev_to_dma_chan(struct device *dev)
155{
156 struct dma_chan_dev *chan_dev;
157
158 chan_dev = container_of(dev, typeof(*chan_dev), device);
159 return chan_dev->chan;
160}
161
162static ssize_t memcpy_count_show(struct device *dev,
163 struct device_attribute *attr, char *buf)
164{
165 struct dma_chan *chan;
166 unsigned long count = 0;
167 int i;
168 int err;
169
170 mutex_lock(&dma_list_mutex);
171 chan = dev_to_dma_chan(dev);
172 if (chan) {
173 for_each_possible_cpu(i)
174 count += per_cpu_ptr(chan->local, i)->memcpy_count;
175 err = sysfs_emit(buf, "%lu\n", count);
176 } else
177 err = -ENODEV;
178 mutex_unlock(&dma_list_mutex);
179
180 return err;
181}
182static DEVICE_ATTR_RO(memcpy_count);
183
184static ssize_t bytes_transferred_show(struct device *dev,
185 struct device_attribute *attr, char *buf)
186{
187 struct dma_chan *chan;
188 unsigned long count = 0;
189 int i;
190 int err;
191
192 mutex_lock(&dma_list_mutex);
193 chan = dev_to_dma_chan(dev);
194 if (chan) {
195 for_each_possible_cpu(i)
196 count += per_cpu_ptr(chan->local, i)->bytes_transferred;
197 err = sysfs_emit(buf, "%lu\n", count);
198 } else
199 err = -ENODEV;
200 mutex_unlock(&dma_list_mutex);
201
202 return err;
203}
204static DEVICE_ATTR_RO(bytes_transferred);
205
206static ssize_t in_use_show(struct device *dev, struct device_attribute *attr,
207 char *buf)
208{
209 struct dma_chan *chan;
210 int err;
211
212 mutex_lock(&dma_list_mutex);
213 chan = dev_to_dma_chan(dev);
214 if (chan)
215 err = sysfs_emit(buf, "%d\n", chan->client_count);
216 else
217 err = -ENODEV;
218 mutex_unlock(&dma_list_mutex);
219
220 return err;
221}
222static DEVICE_ATTR_RO(in_use);
223
224static struct attribute *dma_dev_attrs[] = {
225 &dev_attr_memcpy_count.attr,
226 &dev_attr_bytes_transferred.attr,
227 &dev_attr_in_use.attr,
228 NULL,
229};
230ATTRIBUTE_GROUPS(dma_dev);
231
232static void chan_dev_release(struct device *dev)
233{
234 struct dma_chan_dev *chan_dev;
235
236 chan_dev = container_of(dev, typeof(*chan_dev), device);
237 kfree(chan_dev);
238}
239
240static struct class dma_devclass = {
241 .name = "dma",
242 .dev_groups = dma_dev_groups,
243 .dev_release = chan_dev_release,
244};
245
246/* --- client and device registration --- */
247
248/* enable iteration over all operation types */
249static dma_cap_mask_t dma_cap_mask_all;
250
251/**
252 * struct dma_chan_tbl_ent - tracks channel allocations per core/operation
253 * @chan: associated channel for this entry
254 */
255struct dma_chan_tbl_ent {
256 struct dma_chan *chan;
257};
258
259/* percpu lookup table for memory-to-memory offload providers */
260static struct dma_chan_tbl_ent __percpu *channel_table[DMA_TX_TYPE_END];
261
262static int __init dma_channel_table_init(void)
263{
264 enum dma_transaction_type cap;
265 int err = 0;
266
267 bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END);
268
269 /* 'interrupt', 'private', and 'slave' are channel capabilities,
270 * but are not associated with an operation so they do not need
271 * an entry in the channel_table
272 */
273 clear_bit(DMA_INTERRUPT, dma_cap_mask_all.bits);
274 clear_bit(DMA_PRIVATE, dma_cap_mask_all.bits);
275 clear_bit(DMA_SLAVE, dma_cap_mask_all.bits);
276
277 for_each_dma_cap_mask(cap, dma_cap_mask_all) {
278 channel_table[cap] = alloc_percpu(struct dma_chan_tbl_ent);
279 if (!channel_table[cap]) {
280 err = -ENOMEM;
281 break;
282 }
283 }
284
285 if (err) {
286 pr_err("dmaengine dma_channel_table_init failure: %d\n", err);
287 for_each_dma_cap_mask(cap, dma_cap_mask_all)
288 free_percpu(channel_table[cap]);
289 }
290
291 return err;
292}
293arch_initcall(dma_channel_table_init);
294
295/**
296 * dma_chan_is_local - checks if the channel is in the same NUMA-node as the CPU
297 * @chan: DMA channel to test
298 * @cpu: CPU index which the channel should be close to
299 *
300 * Returns true if the channel is in the same NUMA-node as the CPU.
301 */
302static bool dma_chan_is_local(struct dma_chan *chan, int cpu)
303{
304 int node = dev_to_node(chan->device->dev);
305 return node == NUMA_NO_NODE ||
306 cpumask_test_cpu(cpu, cpumask_of_node(node));
307}
308
309/**
310 * min_chan - finds the channel with min count and in the same NUMA-node as the CPU
311 * @cap: capability to match
312 * @cpu: CPU index which the channel should be close to
313 *
314 * If some channels are close to the given CPU, the one with the lowest
315 * reference count is returned. Otherwise, CPU is ignored and only the
316 * reference count is taken into account.
317 *
318 * Must be called under dma_list_mutex.
319 */
320static struct dma_chan *min_chan(enum dma_transaction_type cap, int cpu)
321{
322 struct dma_device *device;
323 struct dma_chan *chan;
324 struct dma_chan *min = NULL;
325 struct dma_chan *localmin = NULL;
326
327 list_for_each_entry(device, &dma_device_list, global_node) {
328 if (!dma_has_cap(cap, device->cap_mask) ||
329 dma_has_cap(DMA_PRIVATE, device->cap_mask))
330 continue;
331 list_for_each_entry(chan, &device->channels, device_node) {
332 if (!chan->client_count)
333 continue;
334 if (!min || chan->table_count < min->table_count)
335 min = chan;
336
337 if (dma_chan_is_local(chan, cpu))
338 if (!localmin ||
339 chan->table_count < localmin->table_count)
340 localmin = chan;
341 }
342 }
343
344 chan = localmin ? localmin : min;
345
346 if (chan)
347 chan->table_count++;
348
349 return chan;
350}
351
352/**
353 * dma_channel_rebalance - redistribute the available channels
354 *
355 * Optimize for CPU isolation (each CPU gets a dedicated channel for an
356 * operation type) in the SMP case, and operation isolation (avoid
357 * multi-tasking channels) in the non-SMP case.
358 *
359 * Must be called under dma_list_mutex.
360 */
361static void dma_channel_rebalance(void)
362{
363 struct dma_chan *chan;
364 struct dma_device *device;
365 int cpu;
366 int cap;
367
368 /* undo the last distribution */
369 for_each_dma_cap_mask(cap, dma_cap_mask_all)
370 for_each_possible_cpu(cpu)
371 per_cpu_ptr(channel_table[cap], cpu)->chan = NULL;
372
373 list_for_each_entry(device, &dma_device_list, global_node) {
374 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
375 continue;
376 list_for_each_entry(chan, &device->channels, device_node)
377 chan->table_count = 0;
378 }
379
380 /* don't populate the channel_table if no clients are available */
381 if (!dmaengine_ref_count)
382 return;
383
384 /* redistribute available channels */
385 for_each_dma_cap_mask(cap, dma_cap_mask_all)
386 for_each_online_cpu(cpu) {
387 chan = min_chan(cap, cpu);
388 per_cpu_ptr(channel_table[cap], cpu)->chan = chan;
389 }
390}
391
392static int dma_device_satisfies_mask(struct dma_device *device,
393 const dma_cap_mask_t *want)
394{
395 dma_cap_mask_t has;
396
397 bitmap_and(has.bits, want->bits, device->cap_mask.bits,
398 DMA_TX_TYPE_END);
399 return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END);
400}
401
402static struct module *dma_chan_to_owner(struct dma_chan *chan)
403{
404 return chan->device->owner;
405}
406
407/**
408 * balance_ref_count - catch up the channel reference count
409 * @chan: channel to balance ->client_count versus dmaengine_ref_count
410 *
411 * Must be called under dma_list_mutex.
412 */
413static void balance_ref_count(struct dma_chan *chan)
414{
415 struct module *owner = dma_chan_to_owner(chan);
416
417 while (chan->client_count < dmaengine_ref_count) {
418 __module_get(owner);
419 chan->client_count++;
420 }
421}
422
423static void dma_device_release(struct kref *ref)
424{
425 struct dma_device *device = container_of(ref, struct dma_device, ref);
426
427 list_del_rcu(&device->global_node);
428 dma_channel_rebalance();
429
430 if (device->device_release)
431 device->device_release(device);
432}
433
434static void dma_device_put(struct dma_device *device)
435{
436 lockdep_assert_held(&dma_list_mutex);
437 kref_put(&device->ref, dma_device_release);
438}
439
440/**
441 * dma_chan_get - try to grab a DMA channel's parent driver module
442 * @chan: channel to grab
443 *
444 * Must be called under dma_list_mutex.
445 */
446static int dma_chan_get(struct dma_chan *chan)
447{
448 struct module *owner = dma_chan_to_owner(chan);
449 int ret;
450
451 /* The channel is already in use, update client count */
452 if (chan->client_count) {
453 __module_get(owner);
454 chan->client_count++;
455 return 0;
456 }
457
458 if (!try_module_get(owner))
459 return -ENODEV;
460
461 ret = kref_get_unless_zero(&chan->device->ref);
462 if (!ret) {
463 ret = -ENODEV;
464 goto module_put_out;
465 }
466
467 /* allocate upon first client reference */
468 if (chan->device->device_alloc_chan_resources) {
469 ret = chan->device->device_alloc_chan_resources(chan);
470 if (ret < 0)
471 goto err_out;
472 }
473
474 chan->client_count++;
475
476 if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
477 balance_ref_count(chan);
478
479 return 0;
480
481err_out:
482 dma_device_put(chan->device);
483module_put_out:
484 module_put(owner);
485 return ret;
486}
487
488/**
489 * dma_chan_put - drop a reference to a DMA channel's parent driver module
490 * @chan: channel to release
491 *
492 * Must be called under dma_list_mutex.
493 */
494static void dma_chan_put(struct dma_chan *chan)
495{
496 /* This channel is not in use, bail out */
497 if (!chan->client_count)
498 return;
499
500 chan->client_count--;
501
502 /* This channel is not in use anymore, free it */
503 if (!chan->client_count && chan->device->device_free_chan_resources) {
504 /* Make sure all operations have completed */
505 dmaengine_synchronize(chan);
506 chan->device->device_free_chan_resources(chan);
507 }
508
509 /* If the channel is used via a DMA request router, free the mapping */
510 if (chan->router && chan->router->route_free) {
511 chan->router->route_free(chan->router->dev, chan->route_data);
512 chan->router = NULL;
513 chan->route_data = NULL;
514 }
515
516 dma_device_put(chan->device);
517 module_put(dma_chan_to_owner(chan));
518}
519
520enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
521{
522 enum dma_status status;
523 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
524
525 dma_async_issue_pending(chan);
526 do {
527 status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
528 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
529 dev_err(chan->device->dev, "%s: timeout!\n", __func__);
530 return DMA_ERROR;
531 }
532 if (status != DMA_IN_PROGRESS)
533 break;
534 cpu_relax();
535 } while (1);
536
537 return status;
538}
539EXPORT_SYMBOL(dma_sync_wait);
540
541/**
542 * dma_find_channel - find a channel to carry out the operation
543 * @tx_type: transaction type
544 */
545struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
546{
547 return this_cpu_read(channel_table[tx_type]->chan);
548}
549EXPORT_SYMBOL(dma_find_channel);
550
551/**
552 * dma_issue_pending_all - flush all pending operations across all channels
553 */
554void dma_issue_pending_all(void)
555{
556 struct dma_device *device;
557 struct dma_chan *chan;
558
559 rcu_read_lock();
560 list_for_each_entry_rcu(device, &dma_device_list, global_node) {
561 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
562 continue;
563 list_for_each_entry(chan, &device->channels, device_node)
564 if (chan->client_count)
565 device->device_issue_pending(chan);
566 }
567 rcu_read_unlock();
568}
569EXPORT_SYMBOL(dma_issue_pending_all);
570
571int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps)
572{
573 struct dma_device *device;
574
575 if (!chan || !caps)
576 return -EINVAL;
577
578 device = chan->device;
579
580 /* check if the channel supports slave transactions */
581 if (!(test_bit(DMA_SLAVE, device->cap_mask.bits) ||
582 test_bit(DMA_CYCLIC, device->cap_mask.bits)))
583 return -ENXIO;
584
585 /*
586 * Check whether it reports it uses the generic slave
587 * capabilities, if not, that means it doesn't support any
588 * kind of slave capabilities reporting.
589 */
590 if (!device->directions)
591 return -ENXIO;
592
593 caps->src_addr_widths = device->src_addr_widths;
594 caps->dst_addr_widths = device->dst_addr_widths;
595 caps->directions = device->directions;
596 caps->min_burst = device->min_burst;
597 caps->max_burst = device->max_burst;
598 caps->max_sg_burst = device->max_sg_burst;
599 caps->residue_granularity = device->residue_granularity;
600 caps->descriptor_reuse = device->descriptor_reuse;
601 caps->cmd_pause = !!device->device_pause;
602 caps->cmd_resume = !!device->device_resume;
603 caps->cmd_terminate = !!device->device_terminate_all;
604
605 /*
606 * DMA engine device might be configured with non-uniformly
607 * distributed slave capabilities per device channels. In this
608 * case the corresponding driver may provide the device_caps
609 * callback to override the generic capabilities with
610 * channel-specific ones.
611 */
612 if (device->device_caps)
613 device->device_caps(chan, caps);
614
615 return 0;
616}
617EXPORT_SYMBOL_GPL(dma_get_slave_caps);
618
619static struct dma_chan *private_candidate(const dma_cap_mask_t *mask,
620 struct dma_device *dev,
621 dma_filter_fn fn, void *fn_param)
622{
623 struct dma_chan *chan;
624
625 if (mask && !dma_device_satisfies_mask(dev, mask)) {
626 dev_dbg(dev->dev, "%s: wrong capabilities\n", __func__);
627 return NULL;
628 }
629 /* devices with multiple channels need special handling as we need to
630 * ensure that all channels are either private or public.
631 */
632 if (dev->chancnt > 1 && !dma_has_cap(DMA_PRIVATE, dev->cap_mask))
633 list_for_each_entry(chan, &dev->channels, device_node) {
634 /* some channels are already publicly allocated */
635 if (chan->client_count)
636 return NULL;
637 }
638
639 list_for_each_entry(chan, &dev->channels, device_node) {
640 if (chan->client_count) {
641 dev_dbg(dev->dev, "%s: %s busy\n",
642 __func__, dma_chan_name(chan));
643 continue;
644 }
645 if (fn && !fn(chan, fn_param)) {
646 dev_dbg(dev->dev, "%s: %s filter said false\n",
647 __func__, dma_chan_name(chan));
648 continue;
649 }
650 return chan;
651 }
652
653 return NULL;
654}
655
656static struct dma_chan *find_candidate(struct dma_device *device,
657 const dma_cap_mask_t *mask,
658 dma_filter_fn fn, void *fn_param)
659{
660 struct dma_chan *chan = private_candidate(mask, device, fn, fn_param);
661 int err;
662
663 if (chan) {
664 /* Found a suitable channel, try to grab, prep, and return it.
665 * We first set DMA_PRIVATE to disable balance_ref_count as this
666 * channel will not be published in the general-purpose
667 * allocator
668 */
669 dma_cap_set(DMA_PRIVATE, device->cap_mask);
670 device->privatecnt++;
671 err = dma_chan_get(chan);
672
673 if (err) {
674 if (err == -ENODEV) {
675 dev_dbg(device->dev, "%s: %s module removed\n",
676 __func__, dma_chan_name(chan));
677 list_del_rcu(&device->global_node);
678 } else
679 dev_dbg(device->dev,
680 "%s: failed to get %s: (%d)\n",
681 __func__, dma_chan_name(chan), err);
682
683 if (--device->privatecnt == 0)
684 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
685
686 chan = ERR_PTR(err);
687 }
688 }
689
690 return chan ? chan : ERR_PTR(-EPROBE_DEFER);
691}
692
693/**
694 * dma_get_slave_channel - try to get specific channel exclusively
695 * @chan: target channel
696 */
697struct dma_chan *dma_get_slave_channel(struct dma_chan *chan)
698{
699 /* lock against __dma_request_channel */
700 mutex_lock(&dma_list_mutex);
701
702 if (chan->client_count == 0) {
703 struct dma_device *device = chan->device;
704 int err;
705
706 dma_cap_set(DMA_PRIVATE, device->cap_mask);
707 device->privatecnt++;
708 err = dma_chan_get(chan);
709 if (err) {
710 dev_dbg(chan->device->dev,
711 "%s: failed to get %s: (%d)\n",
712 __func__, dma_chan_name(chan), err);
713 chan = NULL;
714 if (--device->privatecnt == 0)
715 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
716 }
717 } else
718 chan = NULL;
719
720 mutex_unlock(&dma_list_mutex);
721
722
723 return chan;
724}
725EXPORT_SYMBOL_GPL(dma_get_slave_channel);
726
727struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)
728{
729 dma_cap_mask_t mask;
730 struct dma_chan *chan;
731
732 dma_cap_zero(mask);
733 dma_cap_set(DMA_SLAVE, mask);
734
735 /* lock against __dma_request_channel */
736 mutex_lock(&dma_list_mutex);
737
738 chan = find_candidate(device, &mask, NULL, NULL);
739
740 mutex_unlock(&dma_list_mutex);
741
742 return IS_ERR(chan) ? NULL : chan;
743}
744EXPORT_SYMBOL_GPL(dma_get_any_slave_channel);
745
746/**
747 * __dma_request_channel - try to allocate an exclusive channel
748 * @mask: capabilities that the channel must satisfy
749 * @fn: optional callback to disposition available channels
750 * @fn_param: opaque parameter to pass to dma_filter_fn()
751 * @np: device node to look for DMA channels
752 *
753 * Returns pointer to appropriate DMA channel on success or NULL.
754 */
755struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
756 dma_filter_fn fn, void *fn_param,
757 struct device_node *np)
758{
759 struct dma_device *device, *_d;
760 struct dma_chan *chan = NULL;
761
762 /* Find a channel */
763 mutex_lock(&dma_list_mutex);
764 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
765 /* Finds a DMA controller with matching device node */
766 if (np && device->dev->of_node && np != device->dev->of_node)
767 continue;
768
769 chan = find_candidate(device, mask, fn, fn_param);
770 if (!IS_ERR(chan))
771 break;
772
773 chan = NULL;
774 }
775 mutex_unlock(&dma_list_mutex);
776
777 pr_debug("%s: %s (%s)\n",
778 __func__,
779 chan ? "success" : "fail",
780 chan ? dma_chan_name(chan) : NULL);
781
782 return chan;
783}
784EXPORT_SYMBOL_GPL(__dma_request_channel);
785
786static const struct dma_slave_map *dma_filter_match(struct dma_device *device,
787 const char *name,
788 struct device *dev)
789{
790 int i;
791
792 if (!device->filter.mapcnt)
793 return NULL;
794
795 for (i = 0; i < device->filter.mapcnt; i++) {
796 const struct dma_slave_map *map = &device->filter.map[i];
797
798 if (!strcmp(map->devname, dev_name(dev)) &&
799 !strcmp(map->slave, name))
800 return map;
801 }
802
803 return NULL;
804}
805
806/**
807 * dma_request_chan - try to allocate an exclusive slave channel
808 * @dev: pointer to client device structure
809 * @name: slave channel name
810 *
811 * Returns pointer to appropriate DMA channel on success or an error pointer.
812 */
813struct dma_chan *dma_request_chan(struct device *dev, const char *name)
814{
815 struct dma_device *d, *_d;
816 struct dma_chan *chan = NULL;
817
818 /* If device-tree is present get slave info from here */
819 if (dev->of_node)
820 chan = of_dma_request_slave_channel(dev->of_node, name);
821
822 /* If device was enumerated by ACPI get slave info from here */
823 if (has_acpi_companion(dev) && !chan)
824 chan = acpi_dma_request_slave_chan_by_name(dev, name);
825
826 if (PTR_ERR(chan) == -EPROBE_DEFER)
827 return chan;
828
829 if (!IS_ERR_OR_NULL(chan))
830 goto found;
831
832 /* Try to find the channel via the DMA filter map(s) */
833 mutex_lock(&dma_list_mutex);
834 list_for_each_entry_safe(d, _d, &dma_device_list, global_node) {
835 dma_cap_mask_t mask;
836 const struct dma_slave_map *map = dma_filter_match(d, name, dev);
837
838 if (!map)
839 continue;
840
841 dma_cap_zero(mask);
842 dma_cap_set(DMA_SLAVE, mask);
843
844 chan = find_candidate(d, &mask, d->filter.fn, map->param);
845 if (!IS_ERR(chan))
846 break;
847 }
848 mutex_unlock(&dma_list_mutex);
849
850 if (IS_ERR(chan))
851 return chan;
852 if (!chan)
853 return ERR_PTR(-EPROBE_DEFER);
854
855found:
856#ifdef CONFIG_DEBUG_FS
857 chan->dbg_client_name = kasprintf(GFP_KERNEL, "%s:%s", dev_name(dev),
858 name);
859#endif
860
861 chan->name = kasprintf(GFP_KERNEL, "dma:%s", name);
862 if (!chan->name)
863 return chan;
864 chan->slave = dev;
865
866 if (sysfs_create_link(&chan->dev->device.kobj, &dev->kobj,
867 DMA_SLAVE_NAME))
868 dev_warn(dev, "Cannot create DMA %s symlink\n", DMA_SLAVE_NAME);
869 if (sysfs_create_link(&dev->kobj, &chan->dev->device.kobj, chan->name))
870 dev_warn(dev, "Cannot create DMA %s symlink\n", chan->name);
871
872 return chan;
873}
874EXPORT_SYMBOL_GPL(dma_request_chan);
875
876/**
877 * dma_request_chan_by_mask - allocate a channel satisfying certain capabilities
878 * @mask: capabilities that the channel must satisfy
879 *
880 * Returns pointer to appropriate DMA channel on success or an error pointer.
881 */
882struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask)
883{
884 struct dma_chan *chan;
885
886 if (!mask)
887 return ERR_PTR(-ENODEV);
888
889 chan = __dma_request_channel(mask, NULL, NULL, NULL);
890 if (!chan) {
891 mutex_lock(&dma_list_mutex);
892 if (list_empty(&dma_device_list))
893 chan = ERR_PTR(-EPROBE_DEFER);
894 else
895 chan = ERR_PTR(-ENODEV);
896 mutex_unlock(&dma_list_mutex);
897 }
898
899 return chan;
900}
901EXPORT_SYMBOL_GPL(dma_request_chan_by_mask);
902
903void dma_release_channel(struct dma_chan *chan)
904{
905 mutex_lock(&dma_list_mutex);
906 WARN_ONCE(chan->client_count != 1,
907 "chan reference count %d != 1\n", chan->client_count);
908 dma_chan_put(chan);
909 /* drop PRIVATE cap enabled by __dma_request_channel() */
910 if (--chan->device->privatecnt == 0)
911 dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
912
913 if (chan->slave) {
914 sysfs_remove_link(&chan->dev->device.kobj, DMA_SLAVE_NAME);
915 sysfs_remove_link(&chan->slave->kobj, chan->name);
916 kfree(chan->name);
917 chan->name = NULL;
918 chan->slave = NULL;
919 }
920
921#ifdef CONFIG_DEBUG_FS
922 kfree(chan->dbg_client_name);
923 chan->dbg_client_name = NULL;
924#endif
925 mutex_unlock(&dma_list_mutex);
926}
927EXPORT_SYMBOL_GPL(dma_release_channel);
928
929/**
930 * dmaengine_get - register interest in dma_channels
931 */
932void dmaengine_get(void)
933{
934 struct dma_device *device, *_d;
935 struct dma_chan *chan;
936 int err;
937
938 mutex_lock(&dma_list_mutex);
939 dmaengine_ref_count++;
940
941 /* try to grab channels */
942 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
943 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
944 continue;
945 list_for_each_entry(chan, &device->channels, device_node) {
946 err = dma_chan_get(chan);
947 if (err == -ENODEV) {
948 /* module removed before we could use it */
949 list_del_rcu(&device->global_node);
950 break;
951 } else if (err)
952 dev_dbg(chan->device->dev,
953 "%s: failed to get %s: (%d)\n",
954 __func__, dma_chan_name(chan), err);
955 }
956 }
957
958 /* if this is the first reference and there were channels
959 * waiting we need to rebalance to get those channels
960 * incorporated into the channel table
961 */
962 if (dmaengine_ref_count == 1)
963 dma_channel_rebalance();
964 mutex_unlock(&dma_list_mutex);
965}
966EXPORT_SYMBOL(dmaengine_get);
967
968/**
969 * dmaengine_put - let DMA drivers be removed when ref_count == 0
970 */
971void dmaengine_put(void)
972{
973 struct dma_device *device, *_d;
974 struct dma_chan *chan;
975
976 mutex_lock(&dma_list_mutex);
977 dmaengine_ref_count--;
978 BUG_ON(dmaengine_ref_count < 0);
979 /* drop channel references */
980 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
981 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
982 continue;
983 list_for_each_entry(chan, &device->channels, device_node)
984 dma_chan_put(chan);
985 }
986 mutex_unlock(&dma_list_mutex);
987}
988EXPORT_SYMBOL(dmaengine_put);
989
990static bool device_has_all_tx_types(struct dma_device *device)
991{
992 /* A device that satisfies this test has channels that will never cause
993 * an async_tx channel switch event as all possible operation types can
994 * be handled.
995 */
996 #ifdef CONFIG_ASYNC_TX_DMA
997 if (!dma_has_cap(DMA_INTERRUPT, device->cap_mask))
998 return false;
999 #endif
1000
1001 #if IS_ENABLED(CONFIG_ASYNC_MEMCPY)
1002 if (!dma_has_cap(DMA_MEMCPY, device->cap_mask))
1003 return false;
1004 #endif
1005
1006 #if IS_ENABLED(CONFIG_ASYNC_XOR)
1007 if (!dma_has_cap(DMA_XOR, device->cap_mask))
1008 return false;
1009
1010 #ifndef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
1011 if (!dma_has_cap(DMA_XOR_VAL, device->cap_mask))
1012 return false;
1013 #endif
1014 #endif
1015
1016 #if IS_ENABLED(CONFIG_ASYNC_PQ)
1017 if (!dma_has_cap(DMA_PQ, device->cap_mask))
1018 return false;
1019
1020 #ifndef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
1021 if (!dma_has_cap(DMA_PQ_VAL, device->cap_mask))
1022 return false;
1023 #endif
1024 #endif
1025
1026 return true;
1027}
1028
1029static int get_dma_id(struct dma_device *device)
1030{
1031 int rc = ida_alloc(&dma_ida, GFP_KERNEL);
1032
1033 if (rc < 0)
1034 return rc;
1035 device->dev_id = rc;
1036 return 0;
1037}
1038
1039static int __dma_async_device_channel_register(struct dma_device *device,
1040 struct dma_chan *chan)
1041{
1042 int rc;
1043
1044 chan->local = alloc_percpu(typeof(*chan->local));
1045 if (!chan->local)
1046 return -ENOMEM;
1047 chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
1048 if (!chan->dev) {
1049 rc = -ENOMEM;
1050 goto err_free_local;
1051 }
1052
1053 /*
1054 * When the chan_id is a negative value, we are dynamically adding
1055 * the channel. Otherwise we are static enumerating.
1056 */
1057 chan->chan_id = ida_alloc(&device->chan_ida, GFP_KERNEL);
1058 if (chan->chan_id < 0) {
1059 pr_err("%s: unable to alloc ida for chan: %d\n",
1060 __func__, chan->chan_id);
1061 rc = chan->chan_id;
1062 goto err_free_dev;
1063 }
1064
1065 chan->dev->device.class = &dma_devclass;
1066 chan->dev->device.parent = device->dev;
1067 chan->dev->chan = chan;
1068 chan->dev->dev_id = device->dev_id;
1069 dev_set_name(&chan->dev->device, "dma%dchan%d",
1070 device->dev_id, chan->chan_id);
1071 rc = device_register(&chan->dev->device);
1072 if (rc)
1073 goto err_out_ida;
1074 chan->client_count = 0;
1075 device->chancnt++;
1076
1077 return 0;
1078
1079 err_out_ida:
1080 ida_free(&device->chan_ida, chan->chan_id);
1081 err_free_dev:
1082 kfree(chan->dev);
1083 err_free_local:
1084 free_percpu(chan->local);
1085 chan->local = NULL;
1086 return rc;
1087}
1088
1089int dma_async_device_channel_register(struct dma_device *device,
1090 struct dma_chan *chan)
1091{
1092 int rc;
1093
1094 rc = __dma_async_device_channel_register(device, chan);
1095 if (rc < 0)
1096 return rc;
1097
1098 dma_channel_rebalance();
1099 return 0;
1100}
1101EXPORT_SYMBOL_GPL(dma_async_device_channel_register);
1102
1103static void __dma_async_device_channel_unregister(struct dma_device *device,
1104 struct dma_chan *chan)
1105{
1106 if (chan->local == NULL)
1107 return;
1108
1109 WARN_ONCE(!device->device_release && chan->client_count,
1110 "%s called while %d clients hold a reference\n",
1111 __func__, chan->client_count);
1112 mutex_lock(&dma_list_mutex);
1113 device->chancnt--;
1114 chan->dev->chan = NULL;
1115 mutex_unlock(&dma_list_mutex);
1116 ida_free(&device->chan_ida, chan->chan_id);
1117 device_unregister(&chan->dev->device);
1118 free_percpu(chan->local);
1119}
1120
1121void dma_async_device_channel_unregister(struct dma_device *device,
1122 struct dma_chan *chan)
1123{
1124 __dma_async_device_channel_unregister(device, chan);
1125 dma_channel_rebalance();
1126}
1127EXPORT_SYMBOL_GPL(dma_async_device_channel_unregister);
1128
1129/**
1130 * dma_async_device_register - registers DMA devices found
1131 * @device: pointer to &struct dma_device
1132 *
1133 * After calling this routine the structure should not be freed except in the
1134 * device_release() callback which will be called after
1135 * dma_async_device_unregister() is called and no further references are taken.
1136 */
1137int dma_async_device_register(struct dma_device *device)
1138{
1139 int rc;
1140 struct dma_chan* chan;
1141
1142 if (!device)
1143 return -ENODEV;
1144
1145 /* validate device routines */
1146 if (!device->dev) {
1147 pr_err("DMAdevice must have dev\n");
1148 return -EIO;
1149 }
1150
1151 device->owner = device->dev->driver->owner;
1152
1153#define CHECK_CAP(_name, _type) \
1154{ \
1155 if (dma_has_cap(_type, device->cap_mask) && !device->device_prep_##_name) { \
1156 dev_err(device->dev, \
1157 "Device claims capability %s, but op is not defined\n", \
1158 __stringify(_type)); \
1159 return -EIO; \
1160 } \
1161}
1162
1163 CHECK_CAP(dma_memcpy, DMA_MEMCPY);
1164 CHECK_CAP(dma_xor, DMA_XOR);
1165 CHECK_CAP(dma_xor_val, DMA_XOR_VAL);
1166 CHECK_CAP(dma_pq, DMA_PQ);
1167 CHECK_CAP(dma_pq_val, DMA_PQ_VAL);
1168 CHECK_CAP(dma_memset, DMA_MEMSET);
1169 CHECK_CAP(dma_interrupt, DMA_INTERRUPT);
1170 CHECK_CAP(dma_cyclic, DMA_CYCLIC);
1171 CHECK_CAP(interleaved_dma, DMA_INTERLEAVE);
1172
1173#undef CHECK_CAP
1174
1175 if (!device->device_tx_status) {
1176 dev_err(device->dev, "Device tx_status is not defined\n");
1177 return -EIO;
1178 }
1179
1180
1181 if (!device->device_issue_pending) {
1182 dev_err(device->dev, "Device issue_pending is not defined\n");
1183 return -EIO;
1184 }
1185
1186 if (!device->device_release)
1187 dev_dbg(device->dev,
1188 "WARN: Device release is not defined so it is not safe to unbind this driver while in use\n");
1189
1190 kref_init(&device->ref);
1191
1192 /* note: this only matters in the
1193 * CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH=n case
1194 */
1195 if (device_has_all_tx_types(device))
1196 dma_cap_set(DMA_ASYNC_TX, device->cap_mask);
1197
1198 rc = get_dma_id(device);
1199 if (rc != 0)
1200 return rc;
1201
1202 ida_init(&device->chan_ida);
1203
1204 /* represent channels in sysfs. Probably want devs too */
1205 list_for_each_entry(chan, &device->channels, device_node) {
1206 rc = __dma_async_device_channel_register(device, chan);
1207 if (rc < 0)
1208 goto err_out;
1209 }
1210
1211 mutex_lock(&dma_list_mutex);
1212 /* take references on public channels */
1213 if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
1214 list_for_each_entry(chan, &device->channels, device_node) {
1215 /* if clients are already waiting for channels we need
1216 * to take references on their behalf
1217 */
1218 if (dma_chan_get(chan) == -ENODEV) {
1219 /* note we can only get here for the first
1220 * channel as the remaining channels are
1221 * guaranteed to get a reference
1222 */
1223 rc = -ENODEV;
1224 mutex_unlock(&dma_list_mutex);
1225 goto err_out;
1226 }
1227 }
1228 list_add_tail_rcu(&device->global_node, &dma_device_list);
1229 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
1230 device->privatecnt++; /* Always private */
1231 dma_channel_rebalance();
1232 mutex_unlock(&dma_list_mutex);
1233
1234 dmaengine_debug_register(device);
1235
1236 return 0;
1237
1238err_out:
1239 /* if we never registered a channel just release the idr */
1240 if (!device->chancnt) {
1241 ida_free(&dma_ida, device->dev_id);
1242 return rc;
1243 }
1244
1245 list_for_each_entry(chan, &device->channels, device_node) {
1246 if (chan->local == NULL)
1247 continue;
1248 mutex_lock(&dma_list_mutex);
1249 chan->dev->chan = NULL;
1250 mutex_unlock(&dma_list_mutex);
1251 device_unregister(&chan->dev->device);
1252 free_percpu(chan->local);
1253 }
1254 return rc;
1255}
1256EXPORT_SYMBOL(dma_async_device_register);
1257
1258/**
1259 * dma_async_device_unregister - unregister a DMA device
1260 * @device: pointer to &struct dma_device
1261 *
1262 * This routine is called by dma driver exit routines, dmaengine holds module
1263 * references to prevent it being called while channels are in use.
1264 */
1265void dma_async_device_unregister(struct dma_device *device)
1266{
1267 struct dma_chan *chan, *n;
1268
1269 dmaengine_debug_unregister(device);
1270
1271 list_for_each_entry_safe(chan, n, &device->channels, device_node)
1272 __dma_async_device_channel_unregister(device, chan);
1273
1274 mutex_lock(&dma_list_mutex);
1275 /*
1276 * setting DMA_PRIVATE ensures the device being torn down will not
1277 * be used in the channel_table
1278 */
1279 dma_cap_set(DMA_PRIVATE, device->cap_mask);
1280 dma_channel_rebalance();
1281 ida_free(&dma_ida, device->dev_id);
1282 dma_device_put(device);
1283 mutex_unlock(&dma_list_mutex);
1284}
1285EXPORT_SYMBOL(dma_async_device_unregister);
1286
1287static void dmaenginem_async_device_unregister(void *device)
1288{
1289 dma_async_device_unregister(device);
1290}
1291
1292/**
1293 * dmaenginem_async_device_register - registers DMA devices found
1294 * @device: pointer to &struct dma_device
1295 *
1296 * The operation is managed and will be undone on driver detach.
1297 */
1298int dmaenginem_async_device_register(struct dma_device *device)
1299{
1300 int ret;
1301
1302 ret = dma_async_device_register(device);
1303 if (ret)
1304 return ret;
1305
1306 return devm_add_action_or_reset(device->dev, dmaenginem_async_device_unregister, device);
1307}
1308EXPORT_SYMBOL(dmaenginem_async_device_register);
1309
1310struct dmaengine_unmap_pool {
1311 struct kmem_cache *cache;
1312 const char *name;
1313 mempool_t *pool;
1314 size_t size;
1315};
1316
1317#define __UNMAP_POOL(x) { .size = x, .name = "dmaengine-unmap-" __stringify(x) }
1318static struct dmaengine_unmap_pool unmap_pool[] = {
1319 __UNMAP_POOL(2),
1320 #if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
1321 __UNMAP_POOL(16),
1322 __UNMAP_POOL(128),
1323 __UNMAP_POOL(256),
1324 #endif
1325};
1326
1327static struct dmaengine_unmap_pool *__get_unmap_pool(int nr)
1328{
1329 int order = get_count_order(nr);
1330
1331 switch (order) {
1332 case 0 ... 1:
1333 return &unmap_pool[0];
1334#if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
1335 case 2 ... 4:
1336 return &unmap_pool[1];
1337 case 5 ... 7:
1338 return &unmap_pool[2];
1339 case 8:
1340 return &unmap_pool[3];
1341#endif
1342 default:
1343 BUG();
1344 return NULL;
1345 }
1346}
1347
1348static void dmaengine_unmap(struct kref *kref)
1349{
1350 struct dmaengine_unmap_data *unmap = container_of(kref, typeof(*unmap), kref);
1351 struct device *dev = unmap->dev;
1352 int cnt, i;
1353
1354 cnt = unmap->to_cnt;
1355 for (i = 0; i < cnt; i++)
1356 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1357 DMA_TO_DEVICE);
1358 cnt += unmap->from_cnt;
1359 for (; i < cnt; i++)
1360 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1361 DMA_FROM_DEVICE);
1362 cnt += unmap->bidi_cnt;
1363 for (; i < cnt; i++) {
1364 if (unmap->addr[i] == 0)
1365 continue;
1366 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1367 DMA_BIDIRECTIONAL);
1368 }
1369 cnt = unmap->map_cnt;
1370 mempool_free(unmap, __get_unmap_pool(cnt)->pool);
1371}
1372
1373void dmaengine_unmap_put(struct dmaengine_unmap_data *unmap)
1374{
1375 if (unmap)
1376 kref_put(&unmap->kref, dmaengine_unmap);
1377}
1378EXPORT_SYMBOL_GPL(dmaengine_unmap_put);
1379
1380static void dmaengine_destroy_unmap_pool(void)
1381{
1382 int i;
1383
1384 for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
1385 struct dmaengine_unmap_pool *p = &unmap_pool[i];
1386
1387 mempool_destroy(p->pool);
1388 p->pool = NULL;
1389 kmem_cache_destroy(p->cache);
1390 p->cache = NULL;
1391 }
1392}
1393
1394static int __init dmaengine_init_unmap_pool(void)
1395{
1396 int i;
1397
1398 for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
1399 struct dmaengine_unmap_pool *p = &unmap_pool[i];
1400 size_t size;
1401
1402 size = sizeof(struct dmaengine_unmap_data) +
1403 sizeof(dma_addr_t) * p->size;
1404
1405 p->cache = kmem_cache_create(p->name, size, 0,
1406 SLAB_HWCACHE_ALIGN, NULL);
1407 if (!p->cache)
1408 break;
1409 p->pool = mempool_create_slab_pool(1, p->cache);
1410 if (!p->pool)
1411 break;
1412 }
1413
1414 if (i == ARRAY_SIZE(unmap_pool))
1415 return 0;
1416
1417 dmaengine_destroy_unmap_pool();
1418 return -ENOMEM;
1419}
1420
1421struct dmaengine_unmap_data *
1422dmaengine_get_unmap_data(struct device *dev, int nr, gfp_t flags)
1423{
1424 struct dmaengine_unmap_data *unmap;
1425
1426 unmap = mempool_alloc(__get_unmap_pool(nr)->pool, flags);
1427 if (!unmap)
1428 return NULL;
1429
1430 memset(unmap, 0, sizeof(*unmap));
1431 kref_init(&unmap->kref);
1432 unmap->dev = dev;
1433 unmap->map_cnt = nr;
1434
1435 return unmap;
1436}
1437EXPORT_SYMBOL(dmaengine_get_unmap_data);
1438
1439void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
1440 struct dma_chan *chan)
1441{
1442 tx->chan = chan;
1443 #ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
1444 spin_lock_init(&tx->lock);
1445 #endif
1446}
1447EXPORT_SYMBOL(dma_async_tx_descriptor_init);
1448
1449static inline int desc_check_and_set_metadata_mode(
1450 struct dma_async_tx_descriptor *desc, enum dma_desc_metadata_mode mode)
1451{
1452 /* Make sure that the metadata mode is not mixed */
1453 if (!desc->desc_metadata_mode) {
1454 if (dmaengine_is_metadata_mode_supported(desc->chan, mode))
1455 desc->desc_metadata_mode = mode;
1456 else
1457 return -ENOTSUPP;
1458 } else if (desc->desc_metadata_mode != mode) {
1459 return -EINVAL;
1460 }
1461
1462 return 0;
1463}
1464
1465int dmaengine_desc_attach_metadata(struct dma_async_tx_descriptor *desc,
1466 void *data, size_t len)
1467{
1468 int ret;
1469
1470 if (!desc)
1471 return -EINVAL;
1472
1473 ret = desc_check_and_set_metadata_mode(desc, DESC_METADATA_CLIENT);
1474 if (ret)
1475 return ret;
1476
1477 if (!desc->metadata_ops || !desc->metadata_ops->attach)
1478 return -ENOTSUPP;
1479
1480 return desc->metadata_ops->attach(desc, data, len);
1481}
1482EXPORT_SYMBOL_GPL(dmaengine_desc_attach_metadata);
1483
1484void *dmaengine_desc_get_metadata_ptr(struct dma_async_tx_descriptor *desc,
1485 size_t *payload_len, size_t *max_len)
1486{
1487 int ret;
1488
1489 if (!desc)
1490 return ERR_PTR(-EINVAL);
1491
1492 ret = desc_check_and_set_metadata_mode(desc, DESC_METADATA_ENGINE);
1493 if (ret)
1494 return ERR_PTR(ret);
1495
1496 if (!desc->metadata_ops || !desc->metadata_ops->get_ptr)
1497 return ERR_PTR(-ENOTSUPP);
1498
1499 return desc->metadata_ops->get_ptr(desc, payload_len, max_len);
1500}
1501EXPORT_SYMBOL_GPL(dmaengine_desc_get_metadata_ptr);
1502
1503int dmaengine_desc_set_metadata_len(struct dma_async_tx_descriptor *desc,
1504 size_t payload_len)
1505{
1506 int ret;
1507
1508 if (!desc)
1509 return -EINVAL;
1510
1511 ret = desc_check_and_set_metadata_mode(desc, DESC_METADATA_ENGINE);
1512 if (ret)
1513 return ret;
1514
1515 if (!desc->metadata_ops || !desc->metadata_ops->set_len)
1516 return -ENOTSUPP;
1517
1518 return desc->metadata_ops->set_len(desc, payload_len);
1519}
1520EXPORT_SYMBOL_GPL(dmaengine_desc_set_metadata_len);
1521
1522/**
1523 * dma_wait_for_async_tx - spin wait for a transaction to complete
1524 * @tx: in-flight transaction to wait on
1525 */
1526enum dma_status
1527dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
1528{
1529 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
1530
1531 if (!tx)
1532 return DMA_COMPLETE;
1533
1534 while (tx->cookie == -EBUSY) {
1535 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
1536 dev_err(tx->chan->device->dev,
1537 "%s timeout waiting for descriptor submission\n",
1538 __func__);
1539 return DMA_ERROR;
1540 }
1541 cpu_relax();
1542 }
1543 return dma_sync_wait(tx->chan, tx->cookie);
1544}
1545EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
1546
1547/**
1548 * dma_run_dependencies - process dependent operations on the target channel
1549 * @tx: transaction with dependencies
1550 *
1551 * Helper routine for DMA drivers to process (start) dependent operations
1552 * on their target channel.
1553 */
1554void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
1555{
1556 struct dma_async_tx_descriptor *dep = txd_next(tx);
1557 struct dma_async_tx_descriptor *dep_next;
1558 struct dma_chan *chan;
1559
1560 if (!dep)
1561 return;
1562
1563 /* we'll submit tx->next now, so clear the link */
1564 txd_clear_next(tx);
1565 chan = dep->chan;
1566
1567 /* keep submitting up until a channel switch is detected
1568 * in that case we will be called again as a result of
1569 * processing the interrupt from async_tx_channel_switch
1570 */
1571 for (; dep; dep = dep_next) {
1572 txd_lock(dep);
1573 txd_clear_parent(dep);
1574 dep_next = txd_next(dep);
1575 if (dep_next && dep_next->chan == chan)
1576 txd_clear_next(dep); /* ->next will be submitted */
1577 else
1578 dep_next = NULL; /* submit current dep and terminate */
1579 txd_unlock(dep);
1580
1581 dep->tx_submit(dep);
1582 }
1583
1584 chan->device->device_issue_pending(chan);
1585}
1586EXPORT_SYMBOL_GPL(dma_run_dependencies);
1587
1588static int __init dma_bus_init(void)
1589{
1590 int err = dmaengine_init_unmap_pool();
1591
1592 if (err)
1593 return err;
1594
1595 err = class_register(&dma_devclass);
1596 if (!err)
1597 dmaengine_debugfs_init();
1598
1599 return err;
1600}
1601arch_initcall(dma_bus_init);
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_IDR(dma_idr);
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 idr_remove(&dma_idr, 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 pr_err("%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 return -ENXIO;
487
488 /*
489 * Check whether it reports it uses the generic slave
490 * capabilities, if not, that means it doesn't support any
491 * kind of slave capabilities reporting.
492 */
493 if (!device->directions)
494 return -ENXIO;
495
496 caps->src_addr_widths = device->src_addr_widths;
497 caps->dst_addr_widths = device->dst_addr_widths;
498 caps->directions = device->directions;
499 caps->max_burst = device->max_burst;
500 caps->residue_granularity = device->residue_granularity;
501 caps->descriptor_reuse = device->descriptor_reuse;
502
503 /*
504 * Some devices implement only pause (e.g. to get residuum) but no
505 * resume. However cmd_pause is advertised as pause AND resume.
506 */
507 caps->cmd_pause = !!(device->device_pause && device->device_resume);
508 caps->cmd_terminate = !!device->device_terminate_all;
509
510 return 0;
511}
512EXPORT_SYMBOL_GPL(dma_get_slave_caps);
513
514static struct dma_chan *private_candidate(const dma_cap_mask_t *mask,
515 struct dma_device *dev,
516 dma_filter_fn fn, void *fn_param)
517{
518 struct dma_chan *chan;
519
520 if (mask && !__dma_device_satisfies_mask(dev, mask)) {
521 pr_debug("%s: wrong capabilities\n", __func__);
522 return NULL;
523 }
524 /* devices with multiple channels need special handling as we need to
525 * ensure that all channels are either private or public.
526 */
527 if (dev->chancnt > 1 && !dma_has_cap(DMA_PRIVATE, dev->cap_mask))
528 list_for_each_entry(chan, &dev->channels, device_node) {
529 /* some channels are already publicly allocated */
530 if (chan->client_count)
531 return NULL;
532 }
533
534 list_for_each_entry(chan, &dev->channels, device_node) {
535 if (chan->client_count) {
536 pr_debug("%s: %s busy\n",
537 __func__, dma_chan_name(chan));
538 continue;
539 }
540 if (fn && !fn(chan, fn_param)) {
541 pr_debug("%s: %s filter said false\n",
542 __func__, dma_chan_name(chan));
543 continue;
544 }
545 return chan;
546 }
547
548 return NULL;
549}
550
551static struct dma_chan *find_candidate(struct dma_device *device,
552 const dma_cap_mask_t *mask,
553 dma_filter_fn fn, void *fn_param)
554{
555 struct dma_chan *chan = private_candidate(mask, device, fn, fn_param);
556 int err;
557
558 if (chan) {
559 /* Found a suitable channel, try to grab, prep, and return it.
560 * We first set DMA_PRIVATE to disable balance_ref_count as this
561 * channel will not be published in the general-purpose
562 * allocator
563 */
564 dma_cap_set(DMA_PRIVATE, device->cap_mask);
565 device->privatecnt++;
566 err = dma_chan_get(chan);
567
568 if (err) {
569 if (err == -ENODEV) {
570 pr_debug("%s: %s module removed\n", __func__,
571 dma_chan_name(chan));
572 list_del_rcu(&device->global_node);
573 } else
574 pr_debug("%s: failed to get %s: (%d)\n",
575 __func__, dma_chan_name(chan), err);
576
577 if (--device->privatecnt == 0)
578 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
579
580 chan = ERR_PTR(err);
581 }
582 }
583
584 return chan ? chan : ERR_PTR(-EPROBE_DEFER);
585}
586
587/**
588 * dma_get_slave_channel - try to get specific channel exclusively
589 * @chan: target channel
590 */
591struct dma_chan *dma_get_slave_channel(struct dma_chan *chan)
592{
593 int err = -EBUSY;
594
595 /* lock against __dma_request_channel */
596 mutex_lock(&dma_list_mutex);
597
598 if (chan->client_count == 0) {
599 struct dma_device *device = chan->device;
600
601 dma_cap_set(DMA_PRIVATE, device->cap_mask);
602 device->privatecnt++;
603 err = dma_chan_get(chan);
604 if (err) {
605 pr_debug("%s: failed to get %s: (%d)\n",
606 __func__, dma_chan_name(chan), err);
607 chan = NULL;
608 if (--device->privatecnt == 0)
609 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
610 }
611 } else
612 chan = NULL;
613
614 mutex_unlock(&dma_list_mutex);
615
616
617 return chan;
618}
619EXPORT_SYMBOL_GPL(dma_get_slave_channel);
620
621struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)
622{
623 dma_cap_mask_t mask;
624 struct dma_chan *chan;
625
626 dma_cap_zero(mask);
627 dma_cap_set(DMA_SLAVE, mask);
628
629 /* lock against __dma_request_channel */
630 mutex_lock(&dma_list_mutex);
631
632 chan = find_candidate(device, &mask, NULL, NULL);
633
634 mutex_unlock(&dma_list_mutex);
635
636 return IS_ERR(chan) ? NULL : chan;
637}
638EXPORT_SYMBOL_GPL(dma_get_any_slave_channel);
639
640/**
641 * __dma_request_channel - try to allocate an exclusive channel
642 * @mask: capabilities that the channel must satisfy
643 * @fn: optional callback to disposition available channels
644 * @fn_param: opaque parameter to pass to dma_filter_fn
645 *
646 * Returns pointer to appropriate DMA channel on success or NULL.
647 */
648struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
649 dma_filter_fn fn, void *fn_param)
650{
651 struct dma_device *device, *_d;
652 struct dma_chan *chan = NULL;
653
654 /* Find a channel */
655 mutex_lock(&dma_list_mutex);
656 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
657 chan = find_candidate(device, mask, fn, fn_param);
658 if (!IS_ERR(chan))
659 break;
660
661 chan = NULL;
662 }
663 mutex_unlock(&dma_list_mutex);
664
665 pr_debug("%s: %s (%s)\n",
666 __func__,
667 chan ? "success" : "fail",
668 chan ? dma_chan_name(chan) : NULL);
669
670 return chan;
671}
672EXPORT_SYMBOL_GPL(__dma_request_channel);
673
674static const struct dma_slave_map *dma_filter_match(struct dma_device *device,
675 const char *name,
676 struct device *dev)
677{
678 int i;
679
680 if (!device->filter.mapcnt)
681 return NULL;
682
683 for (i = 0; i < device->filter.mapcnt; i++) {
684 const struct dma_slave_map *map = &device->filter.map[i];
685
686 if (!strcmp(map->devname, dev_name(dev)) &&
687 !strcmp(map->slave, name))
688 return map;
689 }
690
691 return NULL;
692}
693
694/**
695 * dma_request_chan - try to allocate an exclusive slave channel
696 * @dev: pointer to client device structure
697 * @name: slave channel name
698 *
699 * Returns pointer to appropriate DMA channel on success or an error pointer.
700 */
701struct dma_chan *dma_request_chan(struct device *dev, const char *name)
702{
703 struct dma_device *d, *_d;
704 struct dma_chan *chan = NULL;
705
706 /* If device-tree is present get slave info from here */
707 if (dev->of_node)
708 chan = of_dma_request_slave_channel(dev->of_node, name);
709
710 /* If device was enumerated by ACPI get slave info from here */
711 if (has_acpi_companion(dev) && !chan)
712 chan = acpi_dma_request_slave_chan_by_name(dev, name);
713
714 if (chan) {
715 /* Valid channel found or requester need to be deferred */
716 if (!IS_ERR(chan) || PTR_ERR(chan) == -EPROBE_DEFER)
717 return chan;
718 }
719
720 /* Try to find the channel via the DMA filter map(s) */
721 mutex_lock(&dma_list_mutex);
722 list_for_each_entry_safe(d, _d, &dma_device_list, global_node) {
723 dma_cap_mask_t mask;
724 const struct dma_slave_map *map = dma_filter_match(d, name, dev);
725
726 if (!map)
727 continue;
728
729 dma_cap_zero(mask);
730 dma_cap_set(DMA_SLAVE, mask);
731
732 chan = find_candidate(d, &mask, d->filter.fn, map->param);
733 if (!IS_ERR(chan))
734 break;
735 }
736 mutex_unlock(&dma_list_mutex);
737
738 return chan ? chan : ERR_PTR(-EPROBE_DEFER);
739}
740EXPORT_SYMBOL_GPL(dma_request_chan);
741
742/**
743 * dma_request_slave_channel - try to allocate an exclusive slave channel
744 * @dev: pointer to client device structure
745 * @name: slave channel name
746 *
747 * Returns pointer to appropriate DMA channel on success or NULL.
748 */
749struct dma_chan *dma_request_slave_channel(struct device *dev,
750 const char *name)
751{
752 struct dma_chan *ch = dma_request_chan(dev, name);
753 if (IS_ERR(ch))
754 return NULL;
755
756 return ch;
757}
758EXPORT_SYMBOL_GPL(dma_request_slave_channel);
759
760/**
761 * dma_request_chan_by_mask - allocate a channel satisfying certain capabilities
762 * @mask: capabilities that the channel must satisfy
763 *
764 * Returns pointer to appropriate DMA channel on success or an error pointer.
765 */
766struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask)
767{
768 struct dma_chan *chan;
769
770 if (!mask)
771 return ERR_PTR(-ENODEV);
772
773 chan = __dma_request_channel(mask, NULL, NULL);
774 if (!chan)
775 chan = ERR_PTR(-ENODEV);
776
777 return chan;
778}
779EXPORT_SYMBOL_GPL(dma_request_chan_by_mask);
780
781void dma_release_channel(struct dma_chan *chan)
782{
783 mutex_lock(&dma_list_mutex);
784 WARN_ONCE(chan->client_count != 1,
785 "chan reference count %d != 1\n", chan->client_count);
786 dma_chan_put(chan);
787 /* drop PRIVATE cap enabled by __dma_request_channel() */
788 if (--chan->device->privatecnt == 0)
789 dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
790 mutex_unlock(&dma_list_mutex);
791}
792EXPORT_SYMBOL_GPL(dma_release_channel);
793
794/**
795 * dmaengine_get - register interest in dma_channels
796 */
797void dmaengine_get(void)
798{
799 struct dma_device *device, *_d;
800 struct dma_chan *chan;
801 int err;
802
803 mutex_lock(&dma_list_mutex);
804 dmaengine_ref_count++;
805
806 /* try to grab channels */
807 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
808 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
809 continue;
810 list_for_each_entry(chan, &device->channels, device_node) {
811 err = dma_chan_get(chan);
812 if (err == -ENODEV) {
813 /* module removed before we could use it */
814 list_del_rcu(&device->global_node);
815 break;
816 } else if (err)
817 pr_debug("%s: failed to get %s: (%d)\n",
818 __func__, dma_chan_name(chan), err);
819 }
820 }
821
822 /* if this is the first reference and there were channels
823 * waiting we need to rebalance to get those channels
824 * incorporated into the channel table
825 */
826 if (dmaengine_ref_count == 1)
827 dma_channel_rebalance();
828 mutex_unlock(&dma_list_mutex);
829}
830EXPORT_SYMBOL(dmaengine_get);
831
832/**
833 * dmaengine_put - let dma drivers be removed when ref_count == 0
834 */
835void dmaengine_put(void)
836{
837 struct dma_device *device;
838 struct dma_chan *chan;
839
840 mutex_lock(&dma_list_mutex);
841 dmaengine_ref_count--;
842 BUG_ON(dmaengine_ref_count < 0);
843 /* drop channel references */
844 list_for_each_entry(device, &dma_device_list, global_node) {
845 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
846 continue;
847 list_for_each_entry(chan, &device->channels, device_node)
848 dma_chan_put(chan);
849 }
850 mutex_unlock(&dma_list_mutex);
851}
852EXPORT_SYMBOL(dmaengine_put);
853
854static bool device_has_all_tx_types(struct dma_device *device)
855{
856 /* A device that satisfies this test has channels that will never cause
857 * an async_tx channel switch event as all possible operation types can
858 * be handled.
859 */
860 #ifdef CONFIG_ASYNC_TX_DMA
861 if (!dma_has_cap(DMA_INTERRUPT, device->cap_mask))
862 return false;
863 #endif
864
865 #if defined(CONFIG_ASYNC_MEMCPY) || defined(CONFIG_ASYNC_MEMCPY_MODULE)
866 if (!dma_has_cap(DMA_MEMCPY, device->cap_mask))
867 return false;
868 #endif
869
870 #if defined(CONFIG_ASYNC_XOR) || defined(CONFIG_ASYNC_XOR_MODULE)
871 if (!dma_has_cap(DMA_XOR, device->cap_mask))
872 return false;
873
874 #ifndef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
875 if (!dma_has_cap(DMA_XOR_VAL, device->cap_mask))
876 return false;
877 #endif
878 #endif
879
880 #if defined(CONFIG_ASYNC_PQ) || defined(CONFIG_ASYNC_PQ_MODULE)
881 if (!dma_has_cap(DMA_PQ, device->cap_mask))
882 return false;
883
884 #ifndef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
885 if (!dma_has_cap(DMA_PQ_VAL, device->cap_mask))
886 return false;
887 #endif
888 #endif
889
890 return true;
891}
892
893static int get_dma_id(struct dma_device *device)
894{
895 int rc;
896
897 mutex_lock(&dma_list_mutex);
898
899 rc = idr_alloc(&dma_idr, NULL, 0, 0, GFP_KERNEL);
900 if (rc >= 0)
901 device->dev_id = rc;
902
903 mutex_unlock(&dma_list_mutex);
904 return rc < 0 ? rc : 0;
905}
906
907/**
908 * dma_async_device_register - registers DMA devices found
909 * @device: &dma_device
910 */
911int dma_async_device_register(struct dma_device *device)
912{
913 int chancnt = 0, rc;
914 struct dma_chan* chan;
915 atomic_t *idr_ref;
916
917 if (!device)
918 return -ENODEV;
919
920 /* validate device routines */
921 BUG_ON(dma_has_cap(DMA_MEMCPY, device->cap_mask) &&
922 !device->device_prep_dma_memcpy);
923 BUG_ON(dma_has_cap(DMA_XOR, device->cap_mask) &&
924 !device->device_prep_dma_xor);
925 BUG_ON(dma_has_cap(DMA_XOR_VAL, device->cap_mask) &&
926 !device->device_prep_dma_xor_val);
927 BUG_ON(dma_has_cap(DMA_PQ, device->cap_mask) &&
928 !device->device_prep_dma_pq);
929 BUG_ON(dma_has_cap(DMA_PQ_VAL, device->cap_mask) &&
930 !device->device_prep_dma_pq_val);
931 BUG_ON(dma_has_cap(DMA_MEMSET, device->cap_mask) &&
932 !device->device_prep_dma_memset);
933 BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) &&
934 !device->device_prep_dma_interrupt);
935 BUG_ON(dma_has_cap(DMA_SG, device->cap_mask) &&
936 !device->device_prep_dma_sg);
937 BUG_ON(dma_has_cap(DMA_CYCLIC, device->cap_mask) &&
938 !device->device_prep_dma_cyclic);
939 BUG_ON(dma_has_cap(DMA_INTERLEAVE, device->cap_mask) &&
940 !device->device_prep_interleaved_dma);
941
942 BUG_ON(!device->device_tx_status);
943 BUG_ON(!device->device_issue_pending);
944 BUG_ON(!device->dev);
945
946 /* note: this only matters in the
947 * CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH=n case
948 */
949 if (device_has_all_tx_types(device))
950 dma_cap_set(DMA_ASYNC_TX, device->cap_mask);
951
952 idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL);
953 if (!idr_ref)
954 return -ENOMEM;
955 rc = get_dma_id(device);
956 if (rc != 0) {
957 kfree(idr_ref);
958 return rc;
959 }
960
961 atomic_set(idr_ref, 0);
962
963 /* represent channels in sysfs. Probably want devs too */
964 list_for_each_entry(chan, &device->channels, device_node) {
965 rc = -ENOMEM;
966 chan->local = alloc_percpu(typeof(*chan->local));
967 if (chan->local == NULL)
968 goto err_out;
969 chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
970 if (chan->dev == NULL) {
971 free_percpu(chan->local);
972 chan->local = NULL;
973 goto err_out;
974 }
975
976 chan->chan_id = chancnt++;
977 chan->dev->device.class = &dma_devclass;
978 chan->dev->device.parent = device->dev;
979 chan->dev->chan = chan;
980 chan->dev->idr_ref = idr_ref;
981 chan->dev->dev_id = device->dev_id;
982 atomic_inc(idr_ref);
983 dev_set_name(&chan->dev->device, "dma%dchan%d",
984 device->dev_id, chan->chan_id);
985
986 rc = device_register(&chan->dev->device);
987 if (rc) {
988 free_percpu(chan->local);
989 chan->local = NULL;
990 kfree(chan->dev);
991 atomic_dec(idr_ref);
992 goto err_out;
993 }
994 chan->client_count = 0;
995 }
996 device->chancnt = chancnt;
997
998 mutex_lock(&dma_list_mutex);
999 /* take references on public channels */
1000 if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
1001 list_for_each_entry(chan, &device->channels, device_node) {
1002 /* if clients are already waiting for channels we need
1003 * to take references on their behalf
1004 */
1005 if (dma_chan_get(chan) == -ENODEV) {
1006 /* note we can only get here for the first
1007 * channel as the remaining channels are
1008 * guaranteed to get a reference
1009 */
1010 rc = -ENODEV;
1011 mutex_unlock(&dma_list_mutex);
1012 goto err_out;
1013 }
1014 }
1015 list_add_tail_rcu(&device->global_node, &dma_device_list);
1016 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
1017 device->privatecnt++; /* Always private */
1018 dma_channel_rebalance();
1019 mutex_unlock(&dma_list_mutex);
1020
1021 return 0;
1022
1023err_out:
1024 /* if we never registered a channel just release the idr */
1025 if (atomic_read(idr_ref) == 0) {
1026 mutex_lock(&dma_list_mutex);
1027 idr_remove(&dma_idr, device->dev_id);
1028 mutex_unlock(&dma_list_mutex);
1029 kfree(idr_ref);
1030 return rc;
1031 }
1032
1033 list_for_each_entry(chan, &device->channels, device_node) {
1034 if (chan->local == NULL)
1035 continue;
1036 mutex_lock(&dma_list_mutex);
1037 chan->dev->chan = NULL;
1038 mutex_unlock(&dma_list_mutex);
1039 device_unregister(&chan->dev->device);
1040 free_percpu(chan->local);
1041 }
1042 return rc;
1043}
1044EXPORT_SYMBOL(dma_async_device_register);
1045
1046/**
1047 * dma_async_device_unregister - unregister a DMA device
1048 * @device: &dma_device
1049 *
1050 * This routine is called by dma driver exit routines, dmaengine holds module
1051 * references to prevent it being called while channels are in use.
1052 */
1053void dma_async_device_unregister(struct dma_device *device)
1054{
1055 struct dma_chan *chan;
1056
1057 mutex_lock(&dma_list_mutex);
1058 list_del_rcu(&device->global_node);
1059 dma_channel_rebalance();
1060 mutex_unlock(&dma_list_mutex);
1061
1062 list_for_each_entry(chan, &device->channels, device_node) {
1063 WARN_ONCE(chan->client_count,
1064 "%s called while %d clients hold a reference\n",
1065 __func__, chan->client_count);
1066 mutex_lock(&dma_list_mutex);
1067 chan->dev->chan = NULL;
1068 mutex_unlock(&dma_list_mutex);
1069 device_unregister(&chan->dev->device);
1070 free_percpu(chan->local);
1071 }
1072}
1073EXPORT_SYMBOL(dma_async_device_unregister);
1074
1075struct dmaengine_unmap_pool {
1076 struct kmem_cache *cache;
1077 const char *name;
1078 mempool_t *pool;
1079 size_t size;
1080};
1081
1082#define __UNMAP_POOL(x) { .size = x, .name = "dmaengine-unmap-" __stringify(x) }
1083static struct dmaengine_unmap_pool unmap_pool[] = {
1084 __UNMAP_POOL(2),
1085 #if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
1086 __UNMAP_POOL(16),
1087 __UNMAP_POOL(128),
1088 __UNMAP_POOL(256),
1089 #endif
1090};
1091
1092static struct dmaengine_unmap_pool *__get_unmap_pool(int nr)
1093{
1094 int order = get_count_order(nr);
1095
1096 switch (order) {
1097 case 0 ... 1:
1098 return &unmap_pool[0];
1099 case 2 ... 4:
1100 return &unmap_pool[1];
1101 case 5 ... 7:
1102 return &unmap_pool[2];
1103 case 8:
1104 return &unmap_pool[3];
1105 default:
1106 BUG();
1107 return NULL;
1108 }
1109}
1110
1111static void dmaengine_unmap(struct kref *kref)
1112{
1113 struct dmaengine_unmap_data *unmap = container_of(kref, typeof(*unmap), kref);
1114 struct device *dev = unmap->dev;
1115 int cnt, i;
1116
1117 cnt = unmap->to_cnt;
1118 for (i = 0; i < cnt; i++)
1119 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1120 DMA_TO_DEVICE);
1121 cnt += unmap->from_cnt;
1122 for (; i < cnt; i++)
1123 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1124 DMA_FROM_DEVICE);
1125 cnt += unmap->bidi_cnt;
1126 for (; i < cnt; i++) {
1127 if (unmap->addr[i] == 0)
1128 continue;
1129 dma_unmap_page(dev, unmap->addr[i], unmap->len,
1130 DMA_BIDIRECTIONAL);
1131 }
1132 cnt = unmap->map_cnt;
1133 mempool_free(unmap, __get_unmap_pool(cnt)->pool);
1134}
1135
1136void dmaengine_unmap_put(struct dmaengine_unmap_data *unmap)
1137{
1138 if (unmap)
1139 kref_put(&unmap->kref, dmaengine_unmap);
1140}
1141EXPORT_SYMBOL_GPL(dmaengine_unmap_put);
1142
1143static void dmaengine_destroy_unmap_pool(void)
1144{
1145 int i;
1146
1147 for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
1148 struct dmaengine_unmap_pool *p = &unmap_pool[i];
1149
1150 mempool_destroy(p->pool);
1151 p->pool = NULL;
1152 kmem_cache_destroy(p->cache);
1153 p->cache = NULL;
1154 }
1155}
1156
1157static int __init dmaengine_init_unmap_pool(void)
1158{
1159 int i;
1160
1161 for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
1162 struct dmaengine_unmap_pool *p = &unmap_pool[i];
1163 size_t size;
1164
1165 size = sizeof(struct dmaengine_unmap_data) +
1166 sizeof(dma_addr_t) * p->size;
1167
1168 p->cache = kmem_cache_create(p->name, size, 0,
1169 SLAB_HWCACHE_ALIGN, NULL);
1170 if (!p->cache)
1171 break;
1172 p->pool = mempool_create_slab_pool(1, p->cache);
1173 if (!p->pool)
1174 break;
1175 }
1176
1177 if (i == ARRAY_SIZE(unmap_pool))
1178 return 0;
1179
1180 dmaengine_destroy_unmap_pool();
1181 return -ENOMEM;
1182}
1183
1184struct dmaengine_unmap_data *
1185dmaengine_get_unmap_data(struct device *dev, int nr, gfp_t flags)
1186{
1187 struct dmaengine_unmap_data *unmap;
1188
1189 unmap = mempool_alloc(__get_unmap_pool(nr)->pool, flags);
1190 if (!unmap)
1191 return NULL;
1192
1193 memset(unmap, 0, sizeof(*unmap));
1194 kref_init(&unmap->kref);
1195 unmap->dev = dev;
1196 unmap->map_cnt = nr;
1197
1198 return unmap;
1199}
1200EXPORT_SYMBOL(dmaengine_get_unmap_data);
1201
1202void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
1203 struct dma_chan *chan)
1204{
1205 tx->chan = chan;
1206 #ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
1207 spin_lock_init(&tx->lock);
1208 #endif
1209}
1210EXPORT_SYMBOL(dma_async_tx_descriptor_init);
1211
1212/* dma_wait_for_async_tx - spin wait for a transaction to complete
1213 * @tx: in-flight transaction to wait on
1214 */
1215enum dma_status
1216dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
1217{
1218 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
1219
1220 if (!tx)
1221 return DMA_COMPLETE;
1222
1223 while (tx->cookie == -EBUSY) {
1224 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
1225 pr_err("%s timeout waiting for descriptor submission\n",
1226 __func__);
1227 return DMA_ERROR;
1228 }
1229 cpu_relax();
1230 }
1231 return dma_sync_wait(tx->chan, tx->cookie);
1232}
1233EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
1234
1235/* dma_run_dependencies - helper routine for dma drivers to process
1236 * (start) dependent operations on their target channel
1237 * @tx: transaction with dependencies
1238 */
1239void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
1240{
1241 struct dma_async_tx_descriptor *dep = txd_next(tx);
1242 struct dma_async_tx_descriptor *dep_next;
1243 struct dma_chan *chan;
1244
1245 if (!dep)
1246 return;
1247
1248 /* we'll submit tx->next now, so clear the link */
1249 txd_clear_next(tx);
1250 chan = dep->chan;
1251
1252 /* keep submitting up until a channel switch is detected
1253 * in that case we will be called again as a result of
1254 * processing the interrupt from async_tx_channel_switch
1255 */
1256 for (; dep; dep = dep_next) {
1257 txd_lock(dep);
1258 txd_clear_parent(dep);
1259 dep_next = txd_next(dep);
1260 if (dep_next && dep_next->chan == chan)
1261 txd_clear_next(dep); /* ->next will be submitted */
1262 else
1263 dep_next = NULL; /* submit current dep and terminate */
1264 txd_unlock(dep);
1265
1266 dep->tx_submit(dep);
1267 }
1268
1269 chan->device->device_issue_pending(chan);
1270}
1271EXPORT_SYMBOL_GPL(dma_run_dependencies);
1272
1273static int __init dma_bus_init(void)
1274{
1275 int err = dmaengine_init_unmap_pool();
1276
1277 if (err)
1278 return err;
1279 return class_register(&dma_devclass);
1280}
1281arch_initcall(dma_bus_init);
1282
1283