blob: 5a87384ea4ff5cf58c77b64200a621b8fe616b76 [file] [log] [blame]
Chris Leechc13c8262006-05-23 17:18:44 -07001/*
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 *
Dan Williamsaa1e6f12009-01-06 11:38:17 -070034 * The subsystem keeps a global list of dma_device structs it is protected by a
35 * mutex, dma_list_mutex.
Chris Leechc13c8262006-05-23 17:18:44 -070036 *
Dan Williamsf27c5802009-01-06 11:38:18 -070037 * 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 *
Chris Leechc13c8262006-05-23 17:18:44 -070042 * 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 *
Dan Williamsf27c5802009-01-06 11:38:18 -070045 * See Documentation/dmaengine.txt for more details
Chris Leechc13c8262006-05-23 17:18:44 -070046 */
47
48#include <linux/init.h>
49#include <linux/module.h>
Dan Williams7405f742007-01-02 11:10:43 -070050#include <linux/mm.h>
Chris Leechc13c8262006-05-23 17:18:44 -070051#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>
Dan Williams7405f742007-01-02 11:10:43 -070058#include <linux/jiffies.h>
Dan Williams2ba05622009-01-06 11:38:14 -070059#include <linux/rculist.h>
Dan Williams864498a2009-01-06 11:38:21 -070060#include <linux/idr.h>
Chris Leechc13c8262006-05-23 17:18:44 -070061
62static DEFINE_MUTEX(dma_list_mutex);
63static LIST_HEAD(dma_device_list);
Dan Williams6f49a572009-01-06 11:38:14 -070064static long dmaengine_ref_count;
Dan Williams864498a2009-01-06 11:38:21 -070065static struct idr dma_idr;
Chris Leechc13c8262006-05-23 17:18:44 -070066
67/* --- sysfs implementation --- */
68
Dan Williams41d5e592009-01-06 11:38:21 -070069/**
70 * dev_to_dma_chan - convert a device pointer to the its sysfs container object
71 * @dev - device node
72 *
73 * Must be called under dma_list_mutex
74 */
75static struct dma_chan *dev_to_dma_chan(struct device *dev)
76{
77 struct dma_chan_dev *chan_dev;
78
79 chan_dev = container_of(dev, typeof(*chan_dev), device);
80 return chan_dev->chan;
81}
82
Tony Jones891f78e2007-09-25 02:03:03 +020083static ssize_t show_memcpy_count(struct device *dev, struct device_attribute *attr, char *buf)
Chris Leechc13c8262006-05-23 17:18:44 -070084{
Dan Williams41d5e592009-01-06 11:38:21 -070085 struct dma_chan *chan;
Chris Leechc13c8262006-05-23 17:18:44 -070086 unsigned long count = 0;
87 int i;
Dan Williams41d5e592009-01-06 11:38:21 -070088 int err;
Chris Leechc13c8262006-05-23 17:18:44 -070089
Dan Williams41d5e592009-01-06 11:38:21 -070090 mutex_lock(&dma_list_mutex);
91 chan = dev_to_dma_chan(dev);
92 if (chan) {
93 for_each_possible_cpu(i)
94 count += per_cpu_ptr(chan->local, i)->memcpy_count;
95 err = sprintf(buf, "%lu\n", count);
96 } else
97 err = -ENODEV;
98 mutex_unlock(&dma_list_mutex);
Chris Leechc13c8262006-05-23 17:18:44 -070099
Dan Williams41d5e592009-01-06 11:38:21 -0700100 return err;
Chris Leechc13c8262006-05-23 17:18:44 -0700101}
102
Tony Jones891f78e2007-09-25 02:03:03 +0200103static ssize_t show_bytes_transferred(struct device *dev, struct device_attribute *attr,
104 char *buf)
Chris Leechc13c8262006-05-23 17:18:44 -0700105{
Dan Williams41d5e592009-01-06 11:38:21 -0700106 struct dma_chan *chan;
Chris Leechc13c8262006-05-23 17:18:44 -0700107 unsigned long count = 0;
108 int i;
Dan Williams41d5e592009-01-06 11:38:21 -0700109 int err;
Chris Leechc13c8262006-05-23 17:18:44 -0700110
Dan Williams41d5e592009-01-06 11:38:21 -0700111 mutex_lock(&dma_list_mutex);
112 chan = dev_to_dma_chan(dev);
113 if (chan) {
114 for_each_possible_cpu(i)
115 count += per_cpu_ptr(chan->local, i)->bytes_transferred;
116 err = sprintf(buf, "%lu\n", count);
117 } else
118 err = -ENODEV;
119 mutex_unlock(&dma_list_mutex);
Chris Leechc13c8262006-05-23 17:18:44 -0700120
Dan Williams41d5e592009-01-06 11:38:21 -0700121 return err;
Chris Leechc13c8262006-05-23 17:18:44 -0700122}
123
Tony Jones891f78e2007-09-25 02:03:03 +0200124static ssize_t show_in_use(struct device *dev, struct device_attribute *attr, char *buf)
Chris Leechc13c8262006-05-23 17:18:44 -0700125{
Dan Williams41d5e592009-01-06 11:38:21 -0700126 struct dma_chan *chan;
127 int err;
Chris Leechc13c8262006-05-23 17:18:44 -0700128
Dan Williams41d5e592009-01-06 11:38:21 -0700129 mutex_lock(&dma_list_mutex);
130 chan = dev_to_dma_chan(dev);
131 if (chan)
132 err = sprintf(buf, "%d\n", chan->client_count);
133 else
134 err = -ENODEV;
135 mutex_unlock(&dma_list_mutex);
136
137 return err;
Chris Leechc13c8262006-05-23 17:18:44 -0700138}
139
Tony Jones891f78e2007-09-25 02:03:03 +0200140static struct device_attribute dma_attrs[] = {
Chris Leechc13c8262006-05-23 17:18:44 -0700141 __ATTR(memcpy_count, S_IRUGO, show_memcpy_count, NULL),
142 __ATTR(bytes_transferred, S_IRUGO, show_bytes_transferred, NULL),
143 __ATTR(in_use, S_IRUGO, show_in_use, NULL),
144 __ATTR_NULL
145};
146
Dan Williams41d5e592009-01-06 11:38:21 -0700147static void chan_dev_release(struct device *dev)
148{
149 struct dma_chan_dev *chan_dev;
150
151 chan_dev = container_of(dev, typeof(*chan_dev), device);
Dan Williams864498a2009-01-06 11:38:21 -0700152 if (atomic_dec_and_test(chan_dev->idr_ref)) {
153 mutex_lock(&dma_list_mutex);
154 idr_remove(&dma_idr, chan_dev->dev_id);
155 mutex_unlock(&dma_list_mutex);
156 kfree(chan_dev->idr_ref);
157 }
Dan Williams41d5e592009-01-06 11:38:21 -0700158 kfree(chan_dev);
159}
160
Chris Leechc13c8262006-05-23 17:18:44 -0700161static struct class dma_devclass = {
Tony Jones891f78e2007-09-25 02:03:03 +0200162 .name = "dma",
163 .dev_attrs = dma_attrs,
Dan Williams41d5e592009-01-06 11:38:21 -0700164 .dev_release = chan_dev_release,
Chris Leechc13c8262006-05-23 17:18:44 -0700165};
166
167/* --- client and device registration --- */
168
Dan Williams59b5ec22009-01-06 11:38:15 -0700169#define dma_device_satisfies_mask(device, mask) \
170 __dma_device_satisfies_mask((device), &(mask))
Dan Williamsd379b012007-07-09 11:56:42 -0700171static int
Dan Williams59b5ec22009-01-06 11:38:15 -0700172__dma_device_satisfies_mask(struct dma_device *device, dma_cap_mask_t *want)
Dan Williamsd379b012007-07-09 11:56:42 -0700173{
174 dma_cap_mask_t has;
175
Dan Williams59b5ec22009-01-06 11:38:15 -0700176 bitmap_and(has.bits, want->bits, device->cap_mask.bits,
Dan Williamsd379b012007-07-09 11:56:42 -0700177 DMA_TX_TYPE_END);
178 return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END);
179}
180
Dan Williams6f49a572009-01-06 11:38:14 -0700181static struct module *dma_chan_to_owner(struct dma_chan *chan)
182{
183 return chan->device->dev->driver->owner;
184}
185
186/**
187 * balance_ref_count - catch up the channel reference count
188 * @chan - channel to balance ->client_count versus dmaengine_ref_count
189 *
190 * balance_ref_count must be called under dma_list_mutex
191 */
192static void balance_ref_count(struct dma_chan *chan)
193{
194 struct module *owner = dma_chan_to_owner(chan);
195
196 while (chan->client_count < dmaengine_ref_count) {
197 __module_get(owner);
198 chan->client_count++;
199 }
200}
201
202/**
203 * dma_chan_get - try to grab a dma channel's parent driver module
204 * @chan - channel to grab
205 *
206 * Must be called under dma_list_mutex
207 */
208static int dma_chan_get(struct dma_chan *chan)
209{
210 int err = -ENODEV;
211 struct module *owner = dma_chan_to_owner(chan);
212
213 if (chan->client_count) {
214 __module_get(owner);
215 err = 0;
216 } else if (try_module_get(owner))
217 err = 0;
218
219 if (err == 0)
220 chan->client_count++;
221
222 /* allocate upon first client reference */
223 if (chan->client_count == 1 && err == 0) {
Dan Williamsaa1e6f12009-01-06 11:38:17 -0700224 int desc_cnt = chan->device->device_alloc_chan_resources(chan);
Dan Williams6f49a572009-01-06 11:38:14 -0700225
226 if (desc_cnt < 0) {
227 err = desc_cnt;
228 chan->client_count = 0;
229 module_put(owner);
Dan Williams59b5ec22009-01-06 11:38:15 -0700230 } else if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
Dan Williams6f49a572009-01-06 11:38:14 -0700231 balance_ref_count(chan);
232 }
233
234 return err;
235}
236
237/**
238 * dma_chan_put - drop a reference to a dma channel's parent driver module
239 * @chan - channel to release
240 *
241 * Must be called under dma_list_mutex
242 */
243static void dma_chan_put(struct dma_chan *chan)
244{
245 if (!chan->client_count)
246 return; /* this channel failed alloc_chan_resources */
247 chan->client_count--;
248 module_put(dma_chan_to_owner(chan));
249 if (chan->client_count == 0)
250 chan->device->device_free_chan_resources(chan);
251}
252
Dan Williams7405f742007-01-02 11:10:43 -0700253enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
254{
255 enum dma_status status;
256 unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
257
258 dma_async_issue_pending(chan);
259 do {
260 status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
261 if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
262 printk(KERN_ERR "dma_sync_wait_timeout!\n");
263 return DMA_ERROR;
264 }
265 } while (status == DMA_IN_PROGRESS);
266
267 return status;
268}
269EXPORT_SYMBOL(dma_sync_wait);
270
Chris Leechc13c8262006-05-23 17:18:44 -0700271/**
Dan Williamsbec08512009-01-06 11:38:14 -0700272 * dma_cap_mask_all - enable iteration over all operation types
273 */
274static dma_cap_mask_t dma_cap_mask_all;
275
276/**
277 * dma_chan_tbl_ent - tracks channel allocations per core/operation
278 * @chan - associated channel for this entry
279 */
280struct dma_chan_tbl_ent {
281 struct dma_chan *chan;
282};
283
284/**
285 * channel_table - percpu lookup table for memory-to-memory offload providers
286 */
287static struct dma_chan_tbl_ent *channel_table[DMA_TX_TYPE_END];
288
289static int __init dma_channel_table_init(void)
290{
291 enum dma_transaction_type cap;
292 int err = 0;
293
294 bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END);
295
Dan Williams59b5ec22009-01-06 11:38:15 -0700296 /* 'interrupt', 'private', and 'slave' are channel capabilities,
297 * but are not associated with an operation so they do not need
298 * an entry in the channel_table
Dan Williamsbec08512009-01-06 11:38:14 -0700299 */
300 clear_bit(DMA_INTERRUPT, dma_cap_mask_all.bits);
Dan Williams59b5ec22009-01-06 11:38:15 -0700301 clear_bit(DMA_PRIVATE, dma_cap_mask_all.bits);
Dan Williamsbec08512009-01-06 11:38:14 -0700302 clear_bit(DMA_SLAVE, dma_cap_mask_all.bits);
303
304 for_each_dma_cap_mask(cap, dma_cap_mask_all) {
305 channel_table[cap] = alloc_percpu(struct dma_chan_tbl_ent);
306 if (!channel_table[cap]) {
307 err = -ENOMEM;
308 break;
309 }
310 }
311
312 if (err) {
313 pr_err("dmaengine: initialization failure\n");
314 for_each_dma_cap_mask(cap, dma_cap_mask_all)
315 if (channel_table[cap])
316 free_percpu(channel_table[cap]);
317 }
318
319 return err;
320}
Dan Williams652afc22009-01-06 11:38:22 -0700321arch_initcall(dma_channel_table_init);
Dan Williamsbec08512009-01-06 11:38:14 -0700322
323/**
324 * dma_find_channel - find a channel to carry out the operation
325 * @tx_type: transaction type
326 */
327struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
328{
329 struct dma_chan *chan;
330 int cpu;
331
Dan Williamsbec08512009-01-06 11:38:14 -0700332 cpu = get_cpu();
333 chan = per_cpu_ptr(channel_table[tx_type], cpu)->chan;
334 put_cpu();
335
336 return chan;
337}
338EXPORT_SYMBOL(dma_find_channel);
339
340/**
Dan Williams2ba05622009-01-06 11:38:14 -0700341 * dma_issue_pending_all - flush all pending operations across all channels
342 */
343void dma_issue_pending_all(void)
344{
345 struct dma_device *device;
346 struct dma_chan *chan;
347
Dan Williams2ba05622009-01-06 11:38:14 -0700348 rcu_read_lock();
Dan Williams59b5ec22009-01-06 11:38:15 -0700349 list_for_each_entry_rcu(device, &dma_device_list, global_node) {
350 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
351 continue;
Dan Williams2ba05622009-01-06 11:38:14 -0700352 list_for_each_entry(chan, &device->channels, device_node)
353 if (chan->client_count)
354 device->device_issue_pending(chan);
Dan Williams59b5ec22009-01-06 11:38:15 -0700355 }
Dan Williams2ba05622009-01-06 11:38:14 -0700356 rcu_read_unlock();
357}
358EXPORT_SYMBOL(dma_issue_pending_all);
359
360/**
Dan Williamsbec08512009-01-06 11:38:14 -0700361 * nth_chan - returns the nth channel of the given capability
362 * @cap: capability to match
363 * @n: nth channel desired
364 *
365 * Defaults to returning the channel with the desired capability and the
366 * lowest reference count when 'n' cannot be satisfied. Must be called
367 * under dma_list_mutex.
368 */
369static struct dma_chan *nth_chan(enum dma_transaction_type cap, int n)
370{
371 struct dma_device *device;
372 struct dma_chan *chan;
373 struct dma_chan *ret = NULL;
374 struct dma_chan *min = NULL;
375
376 list_for_each_entry(device, &dma_device_list, global_node) {
Dan Williams59b5ec22009-01-06 11:38:15 -0700377 if (!dma_has_cap(cap, device->cap_mask) ||
378 dma_has_cap(DMA_PRIVATE, device->cap_mask))
Dan Williamsbec08512009-01-06 11:38:14 -0700379 continue;
380 list_for_each_entry(chan, &device->channels, device_node) {
381 if (!chan->client_count)
382 continue;
383 if (!min)
384 min = chan;
385 else if (chan->table_count < min->table_count)
386 min = chan;
387
388 if (n-- == 0) {
389 ret = chan;
390 break; /* done */
391 }
392 }
393 if (ret)
394 break; /* done */
395 }
396
397 if (!ret)
398 ret = min;
399
400 if (ret)
401 ret->table_count++;
402
403 return ret;
404}
405
406/**
407 * dma_channel_rebalance - redistribute the available channels
408 *
409 * Optimize for cpu isolation (each cpu gets a dedicated channel for an
410 * operation type) in the SMP case, and operation isolation (avoid
411 * multi-tasking channels) in the non-SMP case. Must be called under
412 * dma_list_mutex.
413 */
414static void dma_channel_rebalance(void)
415{
416 struct dma_chan *chan;
417 struct dma_device *device;
418 int cpu;
419 int cap;
420 int n;
421
422 /* undo the last distribution */
423 for_each_dma_cap_mask(cap, dma_cap_mask_all)
424 for_each_possible_cpu(cpu)
425 per_cpu_ptr(channel_table[cap], cpu)->chan = NULL;
426
Dan Williams59b5ec22009-01-06 11:38:15 -0700427 list_for_each_entry(device, &dma_device_list, global_node) {
428 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
429 continue;
Dan Williamsbec08512009-01-06 11:38:14 -0700430 list_for_each_entry(chan, &device->channels, device_node)
431 chan->table_count = 0;
Dan Williams59b5ec22009-01-06 11:38:15 -0700432 }
Dan Williamsbec08512009-01-06 11:38:14 -0700433
434 /* don't populate the channel_table if no clients are available */
435 if (!dmaengine_ref_count)
436 return;
437
438 /* redistribute available channels */
439 n = 0;
440 for_each_dma_cap_mask(cap, dma_cap_mask_all)
441 for_each_online_cpu(cpu) {
442 if (num_possible_cpus() > 1)
443 chan = nth_chan(cap, n++);
444 else
445 chan = nth_chan(cap, -1);
446
447 per_cpu_ptr(channel_table[cap], cpu)->chan = chan;
448 }
449}
450
Dan Williamse2346672009-01-06 11:38:21 -0700451static struct dma_chan *private_candidate(dma_cap_mask_t *mask, struct dma_device *dev,
452 dma_filter_fn fn, void *fn_param)
Dan Williams59b5ec22009-01-06 11:38:15 -0700453{
454 struct dma_chan *chan;
Dan Williams59b5ec22009-01-06 11:38:15 -0700455
456 if (!__dma_device_satisfies_mask(dev, mask)) {
457 pr_debug("%s: wrong capabilities\n", __func__);
458 return NULL;
459 }
460 /* devices with multiple channels need special handling as we need to
461 * ensure that all channels are either private or public.
462 */
463 if (dev->chancnt > 1 && !dma_has_cap(DMA_PRIVATE, dev->cap_mask))
464 list_for_each_entry(chan, &dev->channels, device_node) {
465 /* some channels are already publicly allocated */
466 if (chan->client_count)
467 return NULL;
468 }
469
470 list_for_each_entry(chan, &dev->channels, device_node) {
471 if (chan->client_count) {
472 pr_debug("%s: %s busy\n",
Dan Williams41d5e592009-01-06 11:38:21 -0700473 __func__, dma_chan_name(chan));
Dan Williams59b5ec22009-01-06 11:38:15 -0700474 continue;
475 }
Dan Williamse2346672009-01-06 11:38:21 -0700476 if (fn && !fn(chan, fn_param)) {
477 pr_debug("%s: %s filter said false\n",
478 __func__, dma_chan_name(chan));
479 continue;
480 }
481 return chan;
Dan Williams59b5ec22009-01-06 11:38:15 -0700482 }
483
Dan Williamse2346672009-01-06 11:38:21 -0700484 return NULL;
Dan Williams59b5ec22009-01-06 11:38:15 -0700485}
486
487/**
488 * dma_request_channel - try to allocate an exclusive channel
489 * @mask: capabilities that the channel must satisfy
490 * @fn: optional callback to disposition available channels
491 * @fn_param: opaque parameter to pass to dma_filter_fn
492 */
493struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, void *fn_param)
494{
495 struct dma_device *device, *_d;
496 struct dma_chan *chan = NULL;
Dan Williams59b5ec22009-01-06 11:38:15 -0700497 int err;
498
499 /* Find a channel */
500 mutex_lock(&dma_list_mutex);
501 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
Dan Williamse2346672009-01-06 11:38:21 -0700502 chan = private_candidate(mask, device, fn, fn_param);
503 if (chan) {
Dan Williams59b5ec22009-01-06 11:38:15 -0700504 /* Found a suitable channel, try to grab, prep, and
505 * return it. We first set DMA_PRIVATE to disable
506 * balance_ref_count as this channel will not be
507 * published in the general-purpose allocator
508 */
509 dma_cap_set(DMA_PRIVATE, device->cap_mask);
Atsushi Nemoto0f571512009-03-06 20:07:14 +0900510 device->privatecnt++;
Dan Williams59b5ec22009-01-06 11:38:15 -0700511 err = dma_chan_get(chan);
512
513 if (err == -ENODEV) {
514 pr_debug("%s: %s module removed\n", __func__,
Dan Williams41d5e592009-01-06 11:38:21 -0700515 dma_chan_name(chan));
Dan Williams59b5ec22009-01-06 11:38:15 -0700516 list_del_rcu(&device->global_node);
517 } else if (err)
518 pr_err("dmaengine: failed to get %s: (%d)\n",
Dan Williams41d5e592009-01-06 11:38:21 -0700519 dma_chan_name(chan), err);
Dan Williams59b5ec22009-01-06 11:38:15 -0700520 else
521 break;
Atsushi Nemoto0f571512009-03-06 20:07:14 +0900522 if (--device->privatecnt == 0)
523 dma_cap_clear(DMA_PRIVATE, device->cap_mask);
Dan Williams287d8592009-02-18 14:48:26 -0800524 chan->private = NULL;
Dan Williamse2346672009-01-06 11:38:21 -0700525 chan = NULL;
526 }
Dan Williams59b5ec22009-01-06 11:38:15 -0700527 }
528 mutex_unlock(&dma_list_mutex);
529
530 pr_debug("%s: %s (%s)\n", __func__, chan ? "success" : "fail",
Dan Williams41d5e592009-01-06 11:38:21 -0700531 chan ? dma_chan_name(chan) : NULL);
Dan Williams59b5ec22009-01-06 11:38:15 -0700532
533 return chan;
534}
535EXPORT_SYMBOL_GPL(__dma_request_channel);
536
537void dma_release_channel(struct dma_chan *chan)
538{
539 mutex_lock(&dma_list_mutex);
540 WARN_ONCE(chan->client_count != 1,
541 "chan reference count %d != 1\n", chan->client_count);
542 dma_chan_put(chan);
Atsushi Nemoto0f571512009-03-06 20:07:14 +0900543 /* drop PRIVATE cap enabled by __dma_request_channel() */
544 if (--chan->device->privatecnt == 0)
545 dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
Dan Williams287d8592009-02-18 14:48:26 -0800546 chan->private = NULL;
Dan Williams59b5ec22009-01-06 11:38:15 -0700547 mutex_unlock(&dma_list_mutex);
548}
549EXPORT_SYMBOL_GPL(dma_release_channel);
550
Dan Williamsbec08512009-01-06 11:38:14 -0700551/**
Dan Williams209b84a2009-01-06 11:38:17 -0700552 * dmaengine_get - register interest in dma_channels
Chris Leechc13c8262006-05-23 17:18:44 -0700553 */
Dan Williams209b84a2009-01-06 11:38:17 -0700554void dmaengine_get(void)
Chris Leechc13c8262006-05-23 17:18:44 -0700555{
Dan Williams6f49a572009-01-06 11:38:14 -0700556 struct dma_device *device, *_d;
557 struct dma_chan *chan;
558 int err;
559
Chris Leechc13c8262006-05-23 17:18:44 -0700560 mutex_lock(&dma_list_mutex);
Dan Williams6f49a572009-01-06 11:38:14 -0700561 dmaengine_ref_count++;
562
563 /* try to grab channels */
Dan Williams59b5ec22009-01-06 11:38:15 -0700564 list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
565 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
566 continue;
Dan Williams6f49a572009-01-06 11:38:14 -0700567 list_for_each_entry(chan, &device->channels, device_node) {
568 err = dma_chan_get(chan);
569 if (err == -ENODEV) {
570 /* module removed before we could use it */
Dan Williams2ba05622009-01-06 11:38:14 -0700571 list_del_rcu(&device->global_node);
Dan Williams6f49a572009-01-06 11:38:14 -0700572 break;
573 } else if (err)
574 pr_err("dmaengine: failed to get %s: (%d)\n",
Dan Williams41d5e592009-01-06 11:38:21 -0700575 dma_chan_name(chan), err);
Dan Williams6f49a572009-01-06 11:38:14 -0700576 }
Dan Williams59b5ec22009-01-06 11:38:15 -0700577 }
Dan Williams6f49a572009-01-06 11:38:14 -0700578
Dan Williamsbec08512009-01-06 11:38:14 -0700579 /* if this is the first reference and there were channels
580 * waiting we need to rebalance to get those channels
581 * incorporated into the channel table
582 */
583 if (dmaengine_ref_count == 1)
584 dma_channel_rebalance();
Chris Leechc13c8262006-05-23 17:18:44 -0700585 mutex_unlock(&dma_list_mutex);
Chris Leechc13c8262006-05-23 17:18:44 -0700586}
Dan Williams209b84a2009-01-06 11:38:17 -0700587EXPORT_SYMBOL(dmaengine_get);
Chris Leechc13c8262006-05-23 17:18:44 -0700588
589/**
Dan Williams209b84a2009-01-06 11:38:17 -0700590 * dmaengine_put - let dma drivers be removed when ref_count == 0
Chris Leechc13c8262006-05-23 17:18:44 -0700591 */
Dan Williams209b84a2009-01-06 11:38:17 -0700592void dmaengine_put(void)
Chris Leechc13c8262006-05-23 17:18:44 -0700593{
Dan Williamsd379b012007-07-09 11:56:42 -0700594 struct dma_device *device;
Chris Leechc13c8262006-05-23 17:18:44 -0700595 struct dma_chan *chan;
596
Chris Leechc13c8262006-05-23 17:18:44 -0700597 mutex_lock(&dma_list_mutex);
Dan Williams6f49a572009-01-06 11:38:14 -0700598 dmaengine_ref_count--;
599 BUG_ON(dmaengine_ref_count < 0);
600 /* drop channel references */
Dan Williams59b5ec22009-01-06 11:38:15 -0700601 list_for_each_entry(device, &dma_device_list, global_node) {
602 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
603 continue;
Dan Williams6f49a572009-01-06 11:38:14 -0700604 list_for_each_entry(chan, &device->channels, device_node)
605 dma_chan_put(chan);
Dan Williams59b5ec22009-01-06 11:38:15 -0700606 }
Chris Leechc13c8262006-05-23 17:18:44 -0700607 mutex_unlock(&dma_list_mutex);
Chris Leechc13c8262006-05-23 17:18:44 -0700608}
Dan Williams209b84a2009-01-06 11:38:17 -0700609EXPORT_SYMBOL(dmaengine_put);
Chris Leechc13c8262006-05-23 17:18:44 -0700610
Dan Williams257b17c2009-03-25 09:13:23 -0700611static int get_dma_id(struct dma_device *device)
612{
613 int rc;
614
615 idr_retry:
616 if (!idr_pre_get(&dma_idr, GFP_KERNEL))
617 return -ENOMEM;
618 mutex_lock(&dma_list_mutex);
619 rc = idr_get_new(&dma_idr, NULL, &device->dev_id);
620 mutex_unlock(&dma_list_mutex);
621 if (rc == -EAGAIN)
622 goto idr_retry;
623 else if (rc != 0)
624 return rc;
625
626 return 0;
627}
628
Chris Leechc13c8262006-05-23 17:18:44 -0700629/**
Randy Dunlap65088712006-07-03 19:45:31 -0700630 * dma_async_device_register - registers DMA devices found
Chris Leechc13c8262006-05-23 17:18:44 -0700631 * @device: &dma_device
632 */
633int dma_async_device_register(struct dma_device *device)
634{
Jeff Garzikff487fb2007-03-08 09:57:34 -0800635 int chancnt = 0, rc;
Chris Leechc13c8262006-05-23 17:18:44 -0700636 struct dma_chan* chan;
Dan Williams864498a2009-01-06 11:38:21 -0700637 atomic_t *idr_ref;
Chris Leechc13c8262006-05-23 17:18:44 -0700638
639 if (!device)
640 return -ENODEV;
641
Dan Williams7405f742007-01-02 11:10:43 -0700642 /* validate device routines */
643 BUG_ON(dma_has_cap(DMA_MEMCPY, device->cap_mask) &&
644 !device->device_prep_dma_memcpy);
645 BUG_ON(dma_has_cap(DMA_XOR, device->cap_mask) &&
646 !device->device_prep_dma_xor);
647 BUG_ON(dma_has_cap(DMA_ZERO_SUM, device->cap_mask) &&
648 !device->device_prep_dma_zero_sum);
649 BUG_ON(dma_has_cap(DMA_MEMSET, device->cap_mask) &&
650 !device->device_prep_dma_memset);
Zhang Wei9b941c62008-03-13 17:45:28 -0700651 BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) &&
Dan Williams7405f742007-01-02 11:10:43 -0700652 !device->device_prep_dma_interrupt);
Haavard Skinnemoendc0ee6432008-07-08 11:59:35 -0700653 BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
654 !device->device_prep_slave_sg);
655 BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
656 !device->device_terminate_all);
Dan Williams7405f742007-01-02 11:10:43 -0700657
658 BUG_ON(!device->device_alloc_chan_resources);
659 BUG_ON(!device->device_free_chan_resources);
Dan Williams7405f742007-01-02 11:10:43 -0700660 BUG_ON(!device->device_is_tx_complete);
661 BUG_ON(!device->device_issue_pending);
662 BUG_ON(!device->dev);
663
Dan Williams864498a2009-01-06 11:38:21 -0700664 idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL);
665 if (!idr_ref)
666 return -ENOMEM;
Dan Williams257b17c2009-03-25 09:13:23 -0700667 rc = get_dma_id(device);
668 if (rc != 0) {
669 kfree(idr_ref);
Dan Williams864498a2009-01-06 11:38:21 -0700670 return rc;
Dan Williams257b17c2009-03-25 09:13:23 -0700671 }
672
673 atomic_set(idr_ref, 0);
Chris Leechc13c8262006-05-23 17:18:44 -0700674
675 /* represent channels in sysfs. Probably want devs too */
676 list_for_each_entry(chan, &device->channels, device_node) {
Dan Williams257b17c2009-03-25 09:13:23 -0700677 rc = -ENOMEM;
Chris Leechc13c8262006-05-23 17:18:44 -0700678 chan->local = alloc_percpu(typeof(*chan->local));
679 if (chan->local == NULL)
Dan Williams257b17c2009-03-25 09:13:23 -0700680 goto err_out;
Dan Williams41d5e592009-01-06 11:38:21 -0700681 chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
682 if (chan->dev == NULL) {
683 free_percpu(chan->local);
Dan Williams257b17c2009-03-25 09:13:23 -0700684 chan->local = NULL;
685 goto err_out;
Dan Williams41d5e592009-01-06 11:38:21 -0700686 }
Chris Leechc13c8262006-05-23 17:18:44 -0700687
688 chan->chan_id = chancnt++;
Dan Williams41d5e592009-01-06 11:38:21 -0700689 chan->dev->device.class = &dma_devclass;
690 chan->dev->device.parent = device->dev;
691 chan->dev->chan = chan;
Dan Williams864498a2009-01-06 11:38:21 -0700692 chan->dev->idr_ref = idr_ref;
693 chan->dev->dev_id = device->dev_id;
694 atomic_inc(idr_ref);
Dan Williams41d5e592009-01-06 11:38:21 -0700695 dev_set_name(&chan->dev->device, "dma%dchan%d",
Kay Sievers06190d82008-11-11 13:12:33 -0700696 device->dev_id, chan->chan_id);
Chris Leechc13c8262006-05-23 17:18:44 -0700697
Dan Williams41d5e592009-01-06 11:38:21 -0700698 rc = device_register(&chan->dev->device);
Jeff Garzikff487fb2007-03-08 09:57:34 -0800699 if (rc) {
Jeff Garzikff487fb2007-03-08 09:57:34 -0800700 free_percpu(chan->local);
701 chan->local = NULL;
Dan Williams257b17c2009-03-25 09:13:23 -0700702 kfree(chan->dev);
703 atomic_dec(idr_ref);
Jeff Garzikff487fb2007-03-08 09:57:34 -0800704 goto err_out;
705 }
Dan Williams7cc5bf92008-07-08 11:58:21 -0700706 chan->client_count = 0;
Chris Leechc13c8262006-05-23 17:18:44 -0700707 }
Dan Williams59b5ec22009-01-06 11:38:15 -0700708 device->chancnt = chancnt;
Chris Leechc13c8262006-05-23 17:18:44 -0700709
710 mutex_lock(&dma_list_mutex);
Dan Williams59b5ec22009-01-06 11:38:15 -0700711 /* take references on public channels */
712 if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
Dan Williams6f49a572009-01-06 11:38:14 -0700713 list_for_each_entry(chan, &device->channels, device_node) {
714 /* if clients are already waiting for channels we need
715 * to take references on their behalf
716 */
717 if (dma_chan_get(chan) == -ENODEV) {
718 /* note we can only get here for the first
719 * channel as the remaining channels are
720 * guaranteed to get a reference
721 */
722 rc = -ENODEV;
723 mutex_unlock(&dma_list_mutex);
724 goto err_out;
725 }
726 }
Dan Williams2ba05622009-01-06 11:38:14 -0700727 list_add_tail_rcu(&device->global_node, &dma_device_list);
Atsushi Nemoto0f571512009-03-06 20:07:14 +0900728 if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
729 device->privatecnt++; /* Always private */
Dan Williamsbec08512009-01-06 11:38:14 -0700730 dma_channel_rebalance();
Chris Leechc13c8262006-05-23 17:18:44 -0700731 mutex_unlock(&dma_list_mutex);
732
Chris Leechc13c8262006-05-23 17:18:44 -0700733 return 0;
Jeff Garzikff487fb2007-03-08 09:57:34 -0800734
735err_out:
Dan Williams257b17c2009-03-25 09:13:23 -0700736 /* if we never registered a channel just release the idr */
737 if (atomic_read(idr_ref) == 0) {
738 mutex_lock(&dma_list_mutex);
739 idr_remove(&dma_idr, device->dev_id);
740 mutex_unlock(&dma_list_mutex);
741 kfree(idr_ref);
742 return rc;
743 }
744
Jeff Garzikff487fb2007-03-08 09:57:34 -0800745 list_for_each_entry(chan, &device->channels, device_node) {
746 if (chan->local == NULL)
747 continue;
Dan Williams41d5e592009-01-06 11:38:21 -0700748 mutex_lock(&dma_list_mutex);
749 chan->dev->chan = NULL;
750 mutex_unlock(&dma_list_mutex);
751 device_unregister(&chan->dev->device);
Jeff Garzikff487fb2007-03-08 09:57:34 -0800752 free_percpu(chan->local);
753 }
754 return rc;
Chris Leechc13c8262006-05-23 17:18:44 -0700755}
David Brownell765e3d82007-03-16 13:38:05 -0800756EXPORT_SYMBOL(dma_async_device_register);
Chris Leechc13c8262006-05-23 17:18:44 -0700757
758/**
Dan Williams6f49a572009-01-06 11:38:14 -0700759 * dma_async_device_unregister - unregister a DMA device
Randy Dunlap65088712006-07-03 19:45:31 -0700760 * @device: &dma_device
Dan Williamsf27c5802009-01-06 11:38:18 -0700761 *
762 * This routine is called by dma driver exit routines, dmaengine holds module
763 * references to prevent it being called while channels are in use.
Randy Dunlap65088712006-07-03 19:45:31 -0700764 */
765void dma_async_device_unregister(struct dma_device *device)
Chris Leechc13c8262006-05-23 17:18:44 -0700766{
767 struct dma_chan *chan;
Chris Leechc13c8262006-05-23 17:18:44 -0700768
769 mutex_lock(&dma_list_mutex);
Dan Williams2ba05622009-01-06 11:38:14 -0700770 list_del_rcu(&device->global_node);
Dan Williamsbec08512009-01-06 11:38:14 -0700771 dma_channel_rebalance();
Chris Leechc13c8262006-05-23 17:18:44 -0700772 mutex_unlock(&dma_list_mutex);
773
774 list_for_each_entry(chan, &device->channels, device_node) {
Dan Williams6f49a572009-01-06 11:38:14 -0700775 WARN_ONCE(chan->client_count,
776 "%s called while %d clients hold a reference\n",
777 __func__, chan->client_count);
Dan Williams41d5e592009-01-06 11:38:21 -0700778 mutex_lock(&dma_list_mutex);
779 chan->dev->chan = NULL;
780 mutex_unlock(&dma_list_mutex);
781 device_unregister(&chan->dev->device);
Chris Leechc13c8262006-05-23 17:18:44 -0700782 }
Chris Leechc13c8262006-05-23 17:18:44 -0700783}
David Brownell765e3d82007-03-16 13:38:05 -0800784EXPORT_SYMBOL(dma_async_device_unregister);
Chris Leechc13c8262006-05-23 17:18:44 -0700785
Dan Williams7405f742007-01-02 11:10:43 -0700786/**
787 * dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
788 * @chan: DMA channel to offload copy to
789 * @dest: destination address (virtual)
790 * @src: source address (virtual)
791 * @len: length
792 *
793 * Both @dest and @src must be mappable to a bus address according to the
794 * DMA mapping API rules for streaming mappings.
795 * Both @dest and @src must stay memory resident (kernel memory or locked
796 * user space pages).
797 */
798dma_cookie_t
799dma_async_memcpy_buf_to_buf(struct dma_chan *chan, void *dest,
800 void *src, size_t len)
801{
802 struct dma_device *dev = chan->device;
803 struct dma_async_tx_descriptor *tx;
Dan Williams00367312008-02-02 19:49:57 -0700804 dma_addr_t dma_dest, dma_src;
Dan Williams7405f742007-01-02 11:10:43 -0700805 dma_cookie_t cookie;
806 int cpu;
Maciej Sosnowski4f005db2009-04-23 12:31:51 +0200807 unsigned long flags;
Dan Williams7405f742007-01-02 11:10:43 -0700808
Dan Williams00367312008-02-02 19:49:57 -0700809 dma_src = dma_map_single(dev->dev, src, len, DMA_TO_DEVICE);
810 dma_dest = dma_map_single(dev->dev, dest, len, DMA_FROM_DEVICE);
Maciej Sosnowski4f005db2009-04-23 12:31:51 +0200811 flags = DMA_CTRL_ACK |
812 DMA_COMPL_SRC_UNMAP_SINGLE |
813 DMA_COMPL_DEST_UNMAP_SINGLE;
814 tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, flags);
Dan Williams00367312008-02-02 19:49:57 -0700815
816 if (!tx) {
817 dma_unmap_single(dev->dev, dma_src, len, DMA_TO_DEVICE);
818 dma_unmap_single(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
Dan Williams7405f742007-01-02 11:10:43 -0700819 return -ENOMEM;
Dan Williams00367312008-02-02 19:49:57 -0700820 }
Dan Williams7405f742007-01-02 11:10:43 -0700821
Dan Williams7405f742007-01-02 11:10:43 -0700822 tx->callback = NULL;
Dan Williams7405f742007-01-02 11:10:43 -0700823 cookie = tx->tx_submit(tx);
824
825 cpu = get_cpu();
826 per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
827 per_cpu_ptr(chan->local, cpu)->memcpy_count++;
828 put_cpu();
829
830 return cookie;
831}
832EXPORT_SYMBOL(dma_async_memcpy_buf_to_buf);
833
834/**
835 * dma_async_memcpy_buf_to_pg - offloaded copy from address to page
836 * @chan: DMA channel to offload copy to
837 * @page: destination page
838 * @offset: offset in page to copy to
839 * @kdata: source address (virtual)
840 * @len: length
841 *
842 * Both @page/@offset and @kdata must be mappable to a bus address according
843 * to the DMA mapping API rules for streaming mappings.
844 * Both @page/@offset and @kdata must stay memory resident (kernel memory or
845 * locked user space pages)
846 */
847dma_cookie_t
848dma_async_memcpy_buf_to_pg(struct dma_chan *chan, struct page *page,
849 unsigned int offset, void *kdata, size_t len)
850{
851 struct dma_device *dev = chan->device;
852 struct dma_async_tx_descriptor *tx;
Dan Williams00367312008-02-02 19:49:57 -0700853 dma_addr_t dma_dest, dma_src;
Dan Williams7405f742007-01-02 11:10:43 -0700854 dma_cookie_t cookie;
855 int cpu;
Maciej Sosnowski4f005db2009-04-23 12:31:51 +0200856 unsigned long flags;
Dan Williams7405f742007-01-02 11:10:43 -0700857
Dan Williams00367312008-02-02 19:49:57 -0700858 dma_src = dma_map_single(dev->dev, kdata, len, DMA_TO_DEVICE);
859 dma_dest = dma_map_page(dev->dev, page, offset, len, DMA_FROM_DEVICE);
Maciej Sosnowski4f005db2009-04-23 12:31:51 +0200860 flags = DMA_CTRL_ACK | DMA_COMPL_SRC_UNMAP_SINGLE;
861 tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, flags);
Dan Williams00367312008-02-02 19:49:57 -0700862
863 if (!tx) {
864 dma_unmap_single(dev->dev, dma_src, len, DMA_TO_DEVICE);
865 dma_unmap_page(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
Dan Williams7405f742007-01-02 11:10:43 -0700866 return -ENOMEM;
Dan Williams00367312008-02-02 19:49:57 -0700867 }
Dan Williams7405f742007-01-02 11:10:43 -0700868
Dan Williams7405f742007-01-02 11:10:43 -0700869 tx->callback = NULL;
Dan Williams7405f742007-01-02 11:10:43 -0700870 cookie = tx->tx_submit(tx);
871
872 cpu = get_cpu();
873 per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
874 per_cpu_ptr(chan->local, cpu)->memcpy_count++;
875 put_cpu();
876
877 return cookie;
878}
879EXPORT_SYMBOL(dma_async_memcpy_buf_to_pg);
880
881/**
882 * dma_async_memcpy_pg_to_pg - offloaded copy from page to page
883 * @chan: DMA channel to offload copy to
884 * @dest_pg: destination page
885 * @dest_off: offset in page to copy to
886 * @src_pg: source page
887 * @src_off: offset in page to copy from
888 * @len: length
889 *
890 * Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
891 * address according to the DMA mapping API rules for streaming mappings.
892 * Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
893 * (kernel memory or locked user space pages).
894 */
895dma_cookie_t
896dma_async_memcpy_pg_to_pg(struct dma_chan *chan, struct page *dest_pg,
897 unsigned int dest_off, struct page *src_pg, unsigned int src_off,
898 size_t len)
899{
900 struct dma_device *dev = chan->device;
901 struct dma_async_tx_descriptor *tx;
Dan Williams00367312008-02-02 19:49:57 -0700902 dma_addr_t dma_dest, dma_src;
Dan Williams7405f742007-01-02 11:10:43 -0700903 dma_cookie_t cookie;
904 int cpu;
Maciej Sosnowski4f005db2009-04-23 12:31:51 +0200905 unsigned long flags;
Dan Williams7405f742007-01-02 11:10:43 -0700906
Dan Williams00367312008-02-02 19:49:57 -0700907 dma_src = dma_map_page(dev->dev, src_pg, src_off, len, DMA_TO_DEVICE);
908 dma_dest = dma_map_page(dev->dev, dest_pg, dest_off, len,
909 DMA_FROM_DEVICE);
Maciej Sosnowski4f005db2009-04-23 12:31:51 +0200910 flags = DMA_CTRL_ACK;
911 tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, flags);
Dan Williams00367312008-02-02 19:49:57 -0700912
913 if (!tx) {
914 dma_unmap_page(dev->dev, dma_src, len, DMA_TO_DEVICE);
915 dma_unmap_page(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
Dan Williams7405f742007-01-02 11:10:43 -0700916 return -ENOMEM;
Dan Williams00367312008-02-02 19:49:57 -0700917 }
Dan Williams7405f742007-01-02 11:10:43 -0700918
Dan Williams7405f742007-01-02 11:10:43 -0700919 tx->callback = NULL;
Dan Williams7405f742007-01-02 11:10:43 -0700920 cookie = tx->tx_submit(tx);
921
922 cpu = get_cpu();
923 per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
924 per_cpu_ptr(chan->local, cpu)->memcpy_count++;
925 put_cpu();
926
927 return cookie;
928}
929EXPORT_SYMBOL(dma_async_memcpy_pg_to_pg);
930
931void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
932 struct dma_chan *chan)
933{
934 tx->chan = chan;
935 spin_lock_init(&tx->lock);
Dan Williamsccccce22009-03-25 09:13:24 -0700936 INIT_LIST_HEAD(&tx->tx_list);
Dan Williams7405f742007-01-02 11:10:43 -0700937}
938EXPORT_SYMBOL(dma_async_tx_descriptor_init);
939
Dan Williams07f22112009-01-05 17:14:31 -0700940/* dma_wait_for_async_tx - spin wait for a transaction to complete
941 * @tx: in-flight transaction to wait on
942 *
943 * This routine assumes that tx was obtained from a call to async_memcpy,
944 * async_xor, async_memset, etc which ensures that tx is "in-flight" (prepped
945 * and submitted). Walking the parent chain is only meant to cover for DMA
946 * drivers that do not implement the DMA_INTERRUPT capability and may race with
947 * the driver's descriptor cleanup routine.
948 */
949enum dma_status
950dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
951{
952 enum dma_status status;
953 struct dma_async_tx_descriptor *iter;
954 struct dma_async_tx_descriptor *parent;
955
956 if (!tx)
957 return DMA_SUCCESS;
958
959 WARN_ONCE(tx->parent, "%s: speculatively walking dependency chain for"
Dan Williams41d5e592009-01-06 11:38:21 -0700960 " %s\n", __func__, dma_chan_name(tx->chan));
Dan Williams07f22112009-01-05 17:14:31 -0700961
962 /* poll through the dependency chain, return when tx is complete */
963 do {
964 iter = tx;
965
966 /* find the root of the unsubmitted dependency chain */
967 do {
968 parent = iter->parent;
969 if (!parent)
970 break;
971 else
972 iter = parent;
973 } while (parent);
974
975 /* there is a small window for ->parent == NULL and
976 * ->cookie == -EBUSY
977 */
978 while (iter->cookie == -EBUSY)
979 cpu_relax();
980
981 status = dma_sync_wait(iter->chan, iter->cookie);
982 } while (status == DMA_IN_PROGRESS || (iter != tx));
983
984 return status;
985}
986EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
987
988/* dma_run_dependencies - helper routine for dma drivers to process
989 * (start) dependent operations on their target channel
990 * @tx: transaction with dependencies
991 */
992void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
993{
994 struct dma_async_tx_descriptor *dep = tx->next;
995 struct dma_async_tx_descriptor *dep_next;
996 struct dma_chan *chan;
997
998 if (!dep)
999 return;
1000
Yuri Tikhonovdd59b852009-01-12 15:17:20 -07001001 /* we'll submit tx->next now, so clear the link */
1002 tx->next = NULL;
Dan Williams07f22112009-01-05 17:14:31 -07001003 chan = dep->chan;
1004
1005 /* keep submitting up until a channel switch is detected
1006 * in that case we will be called again as a result of
1007 * processing the interrupt from async_tx_channel_switch
1008 */
1009 for (; dep; dep = dep_next) {
1010 spin_lock_bh(&dep->lock);
1011 dep->parent = NULL;
1012 dep_next = dep->next;
1013 if (dep_next && dep_next->chan == chan)
1014 dep->next = NULL; /* ->next will be submitted */
1015 else
1016 dep_next = NULL; /* submit current dep and terminate */
1017 spin_unlock_bh(&dep->lock);
1018
1019 dep->tx_submit(dep);
1020 }
1021
1022 chan->device->device_issue_pending(chan);
1023}
1024EXPORT_SYMBOL_GPL(dma_run_dependencies);
1025
Chris Leechc13c8262006-05-23 17:18:44 -07001026static int __init dma_bus_init(void)
1027{
Dan Williams864498a2009-01-06 11:38:21 -07001028 idr_init(&dma_idr);
Chris Leechc13c8262006-05-23 17:18:44 -07001029 mutex_init(&dma_list_mutex);
1030 return class_register(&dma_devclass);
1031}
Dan Williams652afc22009-01-06 11:38:22 -07001032arch_initcall(dma_bus_init);
Chris Leechc13c8262006-05-23 17:18:44 -07001033
Dan Williamsbec08512009-01-06 11:38:14 -07001034