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Sumit Semwald15bd7e2011-12-26 14:53:15 +05301/*
2 * Framework for buffer objects that can be shared across devices/subsystems.
3 *
4 * Copyright(C) 2011 Linaro Limited. All rights reserved.
5 * Author: Sumit Semwal <sumit.semwal@ti.com>
6 *
7 * Many thanks to linaro-mm-sig list, and specially
8 * Arnd Bergmann <arnd@arndb.de>, Rob Clark <rob@ti.com> and
9 * Daniel Vetter <daniel@ffwll.ch> for their support in creation and
10 * refining of this idea.
11 *
12 * This program is free software; you can redistribute it and/or modify it
13 * under the terms of the GNU General Public License version 2 as published by
14 * the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful, but WITHOUT
17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
18 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
19 * more details.
20 *
21 * You should have received a copy of the GNU General Public License along with
22 * this program. If not, see <http://www.gnu.org/licenses/>.
23 */
24
25#include <linux/fs.h>
26#include <linux/slab.h>
27#include <linux/dma-buf.h>
Maarten Lankhorst3aac4502014-07-01 12:57:26 +020028#include <linux/fence.h>
Sumit Semwald15bd7e2011-12-26 14:53:15 +053029#include <linux/anon_inodes.h>
30#include <linux/export.h>
Sumit Semwalb89e3562013-04-04 11:44:37 +053031#include <linux/debugfs.h>
Sumit Semwal9abdffe2015-05-05 14:56:15 +053032#include <linux/module.h>
Sumit Semwalb89e3562013-04-04 11:44:37 +053033#include <linux/seq_file.h>
Maarten Lankhorst9b495a52014-07-01 12:57:43 +020034#include <linux/poll.h>
Maarten Lankhorst3aac4502014-07-01 12:57:26 +020035#include <linux/reservation.h>
Sumit Semwald15bd7e2011-12-26 14:53:15 +053036
37static inline int is_dma_buf_file(struct file *);
38
Sumit Semwalb89e3562013-04-04 11:44:37 +053039struct dma_buf_list {
40 struct list_head head;
41 struct mutex lock;
42};
43
44static struct dma_buf_list db_list;
45
Sumit Semwald15bd7e2011-12-26 14:53:15 +053046static int dma_buf_release(struct inode *inode, struct file *file)
47{
48 struct dma_buf *dmabuf;
49
50 if (!is_dma_buf_file(file))
51 return -EINVAL;
52
53 dmabuf = file->private_data;
54
Daniel Vetterf00b4da2012-12-20 14:14:23 +010055 BUG_ON(dmabuf->vmapping_counter);
56
Maarten Lankhorst9b495a52014-07-01 12:57:43 +020057 /*
58 * Any fences that a dma-buf poll can wait on should be signaled
59 * before releasing dma-buf. This is the responsibility of each
60 * driver that uses the reservation objects.
61 *
62 * If you hit this BUG() it means someone dropped their ref to the
63 * dma-buf while still having pending operation to the buffer.
64 */
65 BUG_ON(dmabuf->cb_shared.active || dmabuf->cb_excl.active);
66
Sumit Semwald15bd7e2011-12-26 14:53:15 +053067 dmabuf->ops->release(dmabuf);
Sumit Semwalb89e3562013-04-04 11:44:37 +053068
69 mutex_lock(&db_list.lock);
70 list_del(&dmabuf->list_node);
71 mutex_unlock(&db_list.lock);
72
Maarten Lankhorst3aac4502014-07-01 12:57:26 +020073 if (dmabuf->resv == (struct reservation_object *)&dmabuf[1])
74 reservation_object_fini(dmabuf->resv);
75
Sumit Semwal9abdffe2015-05-05 14:56:15 +053076 module_put(dmabuf->owner);
Sumit Semwald15bd7e2011-12-26 14:53:15 +053077 kfree(dmabuf);
78 return 0;
79}
80
Daniel Vetter4c785132012-04-24 14:38:52 +053081static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
82{
83 struct dma_buf *dmabuf;
84
85 if (!is_dma_buf_file(file))
86 return -EINVAL;
87
88 dmabuf = file->private_data;
89
90 /* check for overflowing the buffer's size */
91 if (vma->vm_pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
92 dmabuf->size >> PAGE_SHIFT)
93 return -EINVAL;
94
95 return dmabuf->ops->mmap(dmabuf, vma);
96}
97
Christopher James Halse Rogers19e86972013-09-10 11:36:45 +053098static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence)
99{
100 struct dma_buf *dmabuf;
101 loff_t base;
102
103 if (!is_dma_buf_file(file))
104 return -EBADF;
105
106 dmabuf = file->private_data;
107
108 /* only support discovering the end of the buffer,
109 but also allow SEEK_SET to maintain the idiomatic
110 SEEK_END(0), SEEK_CUR(0) pattern */
111 if (whence == SEEK_END)
112 base = dmabuf->size;
113 else if (whence == SEEK_SET)
114 base = 0;
115 else
116 return -EINVAL;
117
118 if (offset != 0)
119 return -EINVAL;
120
121 return base + offset;
122}
123
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200124static void dma_buf_poll_cb(struct fence *fence, struct fence_cb *cb)
125{
126 struct dma_buf_poll_cb_t *dcb = (struct dma_buf_poll_cb_t *)cb;
127 unsigned long flags;
128
129 spin_lock_irqsave(&dcb->poll->lock, flags);
130 wake_up_locked_poll(dcb->poll, dcb->active);
131 dcb->active = 0;
132 spin_unlock_irqrestore(&dcb->poll->lock, flags);
133}
134
135static unsigned int dma_buf_poll(struct file *file, poll_table *poll)
136{
137 struct dma_buf *dmabuf;
138 struct reservation_object *resv;
Maarten Lankhorst04a5faa2014-07-01 12:57:54 +0200139 struct reservation_object_list *fobj;
140 struct fence *fence_excl;
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200141 unsigned long events;
Maarten Lankhorst3c3b1772014-07-01 12:58:00 +0200142 unsigned shared_count, seq;
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200143
144 dmabuf = file->private_data;
145 if (!dmabuf || !dmabuf->resv)
146 return POLLERR;
147
148 resv = dmabuf->resv;
149
150 poll_wait(file, &dmabuf->poll, poll);
151
152 events = poll_requested_events(poll) & (POLLIN | POLLOUT);
153 if (!events)
154 return 0;
155
Maarten Lankhorst3c3b1772014-07-01 12:58:00 +0200156retry:
157 seq = read_seqcount_begin(&resv->seq);
158 rcu_read_lock();
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200159
Maarten Lankhorst3c3b1772014-07-01 12:58:00 +0200160 fobj = rcu_dereference(resv->fence);
161 if (fobj)
162 shared_count = fobj->shared_count;
163 else
164 shared_count = 0;
165 fence_excl = rcu_dereference(resv->fence_excl);
166 if (read_seqcount_retry(&resv->seq, seq)) {
167 rcu_read_unlock();
168 goto retry;
169 }
Maarten Lankhorst04a5faa2014-07-01 12:57:54 +0200170
171 if (fence_excl && (!(events & POLLOUT) || shared_count == 0)) {
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200172 struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_excl;
173 unsigned long pevents = POLLIN;
174
Maarten Lankhorst04a5faa2014-07-01 12:57:54 +0200175 if (shared_count == 0)
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200176 pevents |= POLLOUT;
177
178 spin_lock_irq(&dmabuf->poll.lock);
179 if (dcb->active) {
180 dcb->active |= pevents;
181 events &= ~pevents;
182 } else
183 dcb->active = pevents;
184 spin_unlock_irq(&dmabuf->poll.lock);
185
186 if (events & pevents) {
Maarten Lankhorst3c3b1772014-07-01 12:58:00 +0200187 if (!fence_get_rcu(fence_excl)) {
188 /* force a recheck */
189 events &= ~pevents;
190 dma_buf_poll_cb(NULL, &dcb->cb);
191 } else if (!fence_add_callback(fence_excl, &dcb->cb,
Maarten Lankhorst04a5faa2014-07-01 12:57:54 +0200192 dma_buf_poll_cb)) {
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200193 events &= ~pevents;
Maarten Lankhorst3c3b1772014-07-01 12:58:00 +0200194 fence_put(fence_excl);
Maarten Lankhorst04a5faa2014-07-01 12:57:54 +0200195 } else {
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200196 /*
197 * No callback queued, wake up any additional
198 * waiters.
199 */
Maarten Lankhorst3c3b1772014-07-01 12:58:00 +0200200 fence_put(fence_excl);
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200201 dma_buf_poll_cb(NULL, &dcb->cb);
Maarten Lankhorst04a5faa2014-07-01 12:57:54 +0200202 }
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200203 }
204 }
205
Maarten Lankhorst04a5faa2014-07-01 12:57:54 +0200206 if ((events & POLLOUT) && shared_count > 0) {
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200207 struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_shared;
208 int i;
209
210 /* Only queue a new callback if no event has fired yet */
211 spin_lock_irq(&dmabuf->poll.lock);
212 if (dcb->active)
213 events &= ~POLLOUT;
214 else
215 dcb->active = POLLOUT;
216 spin_unlock_irq(&dmabuf->poll.lock);
217
218 if (!(events & POLLOUT))
219 goto out;
220
Maarten Lankhorst04a5faa2014-07-01 12:57:54 +0200221 for (i = 0; i < shared_count; ++i) {
Maarten Lankhorst3c3b1772014-07-01 12:58:00 +0200222 struct fence *fence = rcu_dereference(fobj->shared[i]);
Maarten Lankhorst04a5faa2014-07-01 12:57:54 +0200223
Maarten Lankhorst3c3b1772014-07-01 12:58:00 +0200224 if (!fence_get_rcu(fence)) {
225 /*
226 * fence refcount dropped to zero, this means
227 * that fobj has been freed
228 *
229 * call dma_buf_poll_cb and force a recheck!
230 */
231 events &= ~POLLOUT;
232 dma_buf_poll_cb(NULL, &dcb->cb);
233 break;
234 }
Maarten Lankhorst04a5faa2014-07-01 12:57:54 +0200235 if (!fence_add_callback(fence, &dcb->cb,
236 dma_buf_poll_cb)) {
Maarten Lankhorst3c3b1772014-07-01 12:58:00 +0200237 fence_put(fence);
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200238 events &= ~POLLOUT;
239 break;
240 }
Maarten Lankhorst3c3b1772014-07-01 12:58:00 +0200241 fence_put(fence);
Maarten Lankhorst04a5faa2014-07-01 12:57:54 +0200242 }
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200243
244 /* No callback queued, wake up any additional waiters. */
Maarten Lankhorst04a5faa2014-07-01 12:57:54 +0200245 if (i == shared_count)
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200246 dma_buf_poll_cb(NULL, &dcb->cb);
247 }
248
249out:
Maarten Lankhorst3c3b1772014-07-01 12:58:00 +0200250 rcu_read_unlock();
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200251 return events;
252}
253
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530254static const struct file_operations dma_buf_fops = {
255 .release = dma_buf_release,
Daniel Vetter4c785132012-04-24 14:38:52 +0530256 .mmap = dma_buf_mmap_internal,
Christopher James Halse Rogers19e86972013-09-10 11:36:45 +0530257 .llseek = dma_buf_llseek,
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200258 .poll = dma_buf_poll,
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530259};
260
261/*
262 * is_dma_buf_file - Check if struct file* is associated with dma_buf
263 */
264static inline int is_dma_buf_file(struct file *file)
265{
266 return file->f_op == &dma_buf_fops;
267}
268
269/**
Sumit Semwald8fbe342015-01-23 12:53:43 +0530270 * dma_buf_export - Creates a new dma_buf, and associates an anon file
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530271 * with this buffer, so it can be exported.
272 * Also connect the allocator specific data and ops to the buffer.
Sumit Semwal78df9692013-03-22 18:22:16 +0530273 * Additionally, provide a name string for exporter; useful in debugging.
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530274 *
Sumit Semwald8fbe342015-01-23 12:53:43 +0530275 * @exp_info: [in] holds all the export related information provided
276 * by the exporter. see struct dma_buf_export_info
277 * for further details.
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530278 *
279 * Returns, on success, a newly created dma_buf object, which wraps the
280 * supplied private data and operations for dma_buf_ops. On either missing
281 * ops, or error in allocating struct dma_buf, will return negative error.
282 *
283 */
Sumit Semwald8fbe342015-01-23 12:53:43 +0530284struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530285{
286 struct dma_buf *dmabuf;
Sumit Semwald8fbe342015-01-23 12:53:43 +0530287 struct reservation_object *resv = exp_info->resv;
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530288 struct file *file;
Maarten Lankhorst3aac4502014-07-01 12:57:26 +0200289 size_t alloc_size = sizeof(struct dma_buf);
Jagan Teki51366292015-05-21 01:09:31 +0530290
Sumit Semwald8fbe342015-01-23 12:53:43 +0530291 if (!exp_info->resv)
Maarten Lankhorst3aac4502014-07-01 12:57:26 +0200292 alloc_size += sizeof(struct reservation_object);
293 else
294 /* prevent &dma_buf[1] == dma_buf->resv */
295 alloc_size += 1;
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530296
Sumit Semwald8fbe342015-01-23 12:53:43 +0530297 if (WARN_ON(!exp_info->priv
298 || !exp_info->ops
299 || !exp_info->ops->map_dma_buf
300 || !exp_info->ops->unmap_dma_buf
301 || !exp_info->ops->release
302 || !exp_info->ops->kmap_atomic
303 || !exp_info->ops->kmap
304 || !exp_info->ops->mmap)) {
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530305 return ERR_PTR(-EINVAL);
306 }
307
Sumit Semwal9abdffe2015-05-05 14:56:15 +0530308 if (!try_module_get(exp_info->owner))
309 return ERR_PTR(-ENOENT);
310
Maarten Lankhorst3aac4502014-07-01 12:57:26 +0200311 dmabuf = kzalloc(alloc_size, GFP_KERNEL);
Sumit Semwal9abdffe2015-05-05 14:56:15 +0530312 if (!dmabuf) {
313 module_put(exp_info->owner);
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530314 return ERR_PTR(-ENOMEM);
Sumit Semwal9abdffe2015-05-05 14:56:15 +0530315 }
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530316
Sumit Semwald8fbe342015-01-23 12:53:43 +0530317 dmabuf->priv = exp_info->priv;
318 dmabuf->ops = exp_info->ops;
319 dmabuf->size = exp_info->size;
320 dmabuf->exp_name = exp_info->exp_name;
Sumit Semwal9abdffe2015-05-05 14:56:15 +0530321 dmabuf->owner = exp_info->owner;
Maarten Lankhorst9b495a52014-07-01 12:57:43 +0200322 init_waitqueue_head(&dmabuf->poll);
323 dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll;
324 dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0;
325
Maarten Lankhorst3aac4502014-07-01 12:57:26 +0200326 if (!resv) {
327 resv = (struct reservation_object *)&dmabuf[1];
328 reservation_object_init(resv);
329 }
330 dmabuf->resv = resv;
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530331
Sumit Semwald8fbe342015-01-23 12:53:43 +0530332 file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf,
333 exp_info->flags);
Tuomas Tynkkynen9022e242013-08-27 16:30:38 +0300334 if (IS_ERR(file)) {
335 kfree(dmabuf);
336 return ERR_CAST(file);
337 }
Christopher James Halse Rogers19e86972013-09-10 11:36:45 +0530338
339 file->f_mode |= FMODE_LSEEK;
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530340 dmabuf->file = file;
341
342 mutex_init(&dmabuf->lock);
343 INIT_LIST_HEAD(&dmabuf->attachments);
344
Sumit Semwalb89e3562013-04-04 11:44:37 +0530345 mutex_lock(&db_list.lock);
346 list_add(&dmabuf->list_node, &db_list.head);
347 mutex_unlock(&db_list.lock);
348
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530349 return dmabuf;
350}
Sumit Semwald8fbe342015-01-23 12:53:43 +0530351EXPORT_SYMBOL_GPL(dma_buf_export);
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530352
353/**
354 * dma_buf_fd - returns a file descriptor for the given dma_buf
355 * @dmabuf: [in] pointer to dma_buf for which fd is required.
Dave Airlie55c1c4c2012-03-16 10:34:02 +0000356 * @flags: [in] flags to give to fd
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530357 *
358 * On success, returns an associated 'fd'. Else, returns error.
359 */
Dave Airlie55c1c4c2012-03-16 10:34:02 +0000360int dma_buf_fd(struct dma_buf *dmabuf, int flags)
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530361{
Borislav Petkovf5e097f2012-12-11 16:05:26 +0100362 int fd;
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530363
364 if (!dmabuf || !dmabuf->file)
365 return -EINVAL;
366
Borislav Petkovf5e097f2012-12-11 16:05:26 +0100367 fd = get_unused_fd_flags(flags);
368 if (fd < 0)
369 return fd;
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530370
371 fd_install(fd, dmabuf->file);
372
373 return fd;
374}
375EXPORT_SYMBOL_GPL(dma_buf_fd);
376
377/**
378 * dma_buf_get - returns the dma_buf structure related to an fd
379 * @fd: [in] fd associated with the dma_buf to be returned
380 *
381 * On success, returns the dma_buf structure associated with an fd; uses
382 * file's refcounting done by fget to increase refcount. returns ERR_PTR
383 * otherwise.
384 */
385struct dma_buf *dma_buf_get(int fd)
386{
387 struct file *file;
388
389 file = fget(fd);
390
391 if (!file)
392 return ERR_PTR(-EBADF);
393
394 if (!is_dma_buf_file(file)) {
395 fput(file);
396 return ERR_PTR(-EINVAL);
397 }
398
399 return file->private_data;
400}
401EXPORT_SYMBOL_GPL(dma_buf_get);
402
403/**
404 * dma_buf_put - decreases refcount of the buffer
405 * @dmabuf: [in] buffer to reduce refcount of
406 *
407 * Uses file's refcounting done implicitly by fput()
408 */
409void dma_buf_put(struct dma_buf *dmabuf)
410{
411 if (WARN_ON(!dmabuf || !dmabuf->file))
412 return;
413
414 fput(dmabuf->file);
415}
416EXPORT_SYMBOL_GPL(dma_buf_put);
417
418/**
419 * dma_buf_attach - Add the device to dma_buf's attachments list; optionally,
420 * calls attach() of dma_buf_ops to allow device-specific attach functionality
421 * @dmabuf: [in] buffer to attach device to.
422 * @dev: [in] device to be attached.
423 *
Colin Crossfee0c542013-12-20 16:43:50 -0800424 * Returns struct dma_buf_attachment * for this attachment; returns ERR_PTR on
425 * error.
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530426 */
427struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
428 struct device *dev)
429{
430 struct dma_buf_attachment *attach;
431 int ret;
432
Laurent Pinchartd1aa06a2012-01-26 12:27:23 +0100433 if (WARN_ON(!dmabuf || !dev))
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530434 return ERR_PTR(-EINVAL);
435
436 attach = kzalloc(sizeof(struct dma_buf_attachment), GFP_KERNEL);
437 if (attach == NULL)
Laurent Pincharta9fbc3b2012-01-26 12:27:24 +0100438 return ERR_PTR(-ENOMEM);
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530439
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530440 attach->dev = dev;
441 attach->dmabuf = dmabuf;
Laurent Pinchart2ed92012012-01-26 12:27:25 +0100442
443 mutex_lock(&dmabuf->lock);
444
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530445 if (dmabuf->ops->attach) {
446 ret = dmabuf->ops->attach(dmabuf, dev, attach);
447 if (ret)
448 goto err_attach;
449 }
450 list_add(&attach->node, &dmabuf->attachments);
451
452 mutex_unlock(&dmabuf->lock);
453 return attach;
454
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530455err_attach:
456 kfree(attach);
457 mutex_unlock(&dmabuf->lock);
458 return ERR_PTR(ret);
459}
460EXPORT_SYMBOL_GPL(dma_buf_attach);
461
462/**
463 * dma_buf_detach - Remove the given attachment from dmabuf's attachments list;
464 * optionally calls detach() of dma_buf_ops for device-specific detach
465 * @dmabuf: [in] buffer to detach from.
466 * @attach: [in] attachment to be detached; is free'd after this call.
467 *
468 */
469void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
470{
Laurent Pinchartd1aa06a2012-01-26 12:27:23 +0100471 if (WARN_ON(!dmabuf || !attach))
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530472 return;
473
474 mutex_lock(&dmabuf->lock);
475 list_del(&attach->node);
476 if (dmabuf->ops->detach)
477 dmabuf->ops->detach(dmabuf, attach);
478
479 mutex_unlock(&dmabuf->lock);
480 kfree(attach);
481}
482EXPORT_SYMBOL_GPL(dma_buf_detach);
483
484/**
485 * dma_buf_map_attachment - Returns the scatterlist table of the attachment;
486 * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
487 * dma_buf_ops.
488 * @attach: [in] attachment whose scatterlist is to be returned
489 * @direction: [in] direction of DMA transfer
490 *
Colin Crossfee0c542013-12-20 16:43:50 -0800491 * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR
492 * on error.
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530493 */
494struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
495 enum dma_data_direction direction)
496{
497 struct sg_table *sg_table = ERR_PTR(-EINVAL);
498
499 might_sleep();
500
Laurent Pinchartd1aa06a2012-01-26 12:27:23 +0100501 if (WARN_ON(!attach || !attach->dmabuf))
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530502 return ERR_PTR(-EINVAL);
503
Laurent Pinchartd1aa06a2012-01-26 12:27:23 +0100504 sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
Colin Crossfee0c542013-12-20 16:43:50 -0800505 if (!sg_table)
506 sg_table = ERR_PTR(-ENOMEM);
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530507
508 return sg_table;
509}
510EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
511
512/**
513 * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
514 * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
515 * dma_buf_ops.
516 * @attach: [in] attachment to unmap buffer from
517 * @sg_table: [in] scatterlist info of the buffer to unmap
Sumit Semwal33ea2dc2012-01-27 15:09:27 +0530518 * @direction: [in] direction of DMA transfer
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530519 *
520 */
521void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
Sumit Semwal33ea2dc2012-01-27 15:09:27 +0530522 struct sg_table *sg_table,
523 enum dma_data_direction direction)
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530524{
Rob Clarkb6fa0cd2012-09-28 09:29:43 +0200525 might_sleep();
526
Laurent Pinchartd1aa06a2012-01-26 12:27:23 +0100527 if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530528 return;
529
Sumit Semwal33ea2dc2012-01-27 15:09:27 +0530530 attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,
531 direction);
Sumit Semwald15bd7e2011-12-26 14:53:15 +0530532}
533EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
Daniel Vetterfc130202012-03-20 00:02:37 +0100534
535
536/**
537 * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
538 * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific
539 * preparations. Coherency is only guaranteed in the specified range for the
540 * specified access direction.
Randy Dunlapefb4df822012-04-17 17:03:30 -0700541 * @dmabuf: [in] buffer to prepare cpu access for.
Daniel Vetterfc130202012-03-20 00:02:37 +0100542 * @direction: [in] length of range for cpu access.
543 *
544 * Can return negative error values, returns 0 on success.
545 */
Tiago Vignatti831e9da2015-12-22 19:36:45 -0200546int dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
Daniel Vetterfc130202012-03-20 00:02:37 +0100547 enum dma_data_direction direction)
548{
549 int ret = 0;
550
551 if (WARN_ON(!dmabuf))
552 return -EINVAL;
553
554 if (dmabuf->ops->begin_cpu_access)
Tiago Vignatti831e9da2015-12-22 19:36:45 -0200555 ret = dmabuf->ops->begin_cpu_access(dmabuf, direction);
Daniel Vetterfc130202012-03-20 00:02:37 +0100556
557 return ret;
558}
559EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access);
560
561/**
562 * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the
563 * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific
564 * actions. Coherency is only guaranteed in the specified range for the
565 * specified access direction.
Randy Dunlapefb4df822012-04-17 17:03:30 -0700566 * @dmabuf: [in] buffer to complete cpu access for.
Daniel Vetterfc130202012-03-20 00:02:37 +0100567 * @direction: [in] length of range for cpu access.
568 *
569 * This call must always succeed.
570 */
Tiago Vignatti831e9da2015-12-22 19:36:45 -0200571void dma_buf_end_cpu_access(struct dma_buf *dmabuf,
Daniel Vetterfc130202012-03-20 00:02:37 +0100572 enum dma_data_direction direction)
573{
574 WARN_ON(!dmabuf);
575
576 if (dmabuf->ops->end_cpu_access)
Tiago Vignatti831e9da2015-12-22 19:36:45 -0200577 dmabuf->ops->end_cpu_access(dmabuf, direction);
Daniel Vetterfc130202012-03-20 00:02:37 +0100578}
579EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access);
580
581/**
582 * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address
583 * space. The same restrictions as for kmap_atomic and friends apply.
Randy Dunlapefb4df822012-04-17 17:03:30 -0700584 * @dmabuf: [in] buffer to map page from.
Daniel Vetterfc130202012-03-20 00:02:37 +0100585 * @page_num: [in] page in PAGE_SIZE units to map.
586 *
587 * This call must always succeed, any necessary preparations that might fail
588 * need to be done in begin_cpu_access.
589 */
590void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num)
591{
592 WARN_ON(!dmabuf);
593
594 return dmabuf->ops->kmap_atomic(dmabuf, page_num);
595}
596EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic);
597
598/**
599 * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic.
Randy Dunlapefb4df822012-04-17 17:03:30 -0700600 * @dmabuf: [in] buffer to unmap page from.
Daniel Vetterfc130202012-03-20 00:02:37 +0100601 * @page_num: [in] page in PAGE_SIZE units to unmap.
602 * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap_atomic.
603 *
604 * This call must always succeed.
605 */
606void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, unsigned long page_num,
607 void *vaddr)
608{
609 WARN_ON(!dmabuf);
610
611 if (dmabuf->ops->kunmap_atomic)
612 dmabuf->ops->kunmap_atomic(dmabuf, page_num, vaddr);
613}
614EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic);
615
616/**
617 * dma_buf_kmap - Map a page of the buffer object into kernel address space. The
618 * same restrictions as for kmap and friends apply.
Randy Dunlapefb4df822012-04-17 17:03:30 -0700619 * @dmabuf: [in] buffer to map page from.
Daniel Vetterfc130202012-03-20 00:02:37 +0100620 * @page_num: [in] page in PAGE_SIZE units to map.
621 *
622 * This call must always succeed, any necessary preparations that might fail
623 * need to be done in begin_cpu_access.
624 */
625void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num)
626{
627 WARN_ON(!dmabuf);
628
629 return dmabuf->ops->kmap(dmabuf, page_num);
630}
631EXPORT_SYMBOL_GPL(dma_buf_kmap);
632
633/**
634 * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap.
Randy Dunlapefb4df822012-04-17 17:03:30 -0700635 * @dmabuf: [in] buffer to unmap page from.
Daniel Vetterfc130202012-03-20 00:02:37 +0100636 * @page_num: [in] page in PAGE_SIZE units to unmap.
637 * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap.
638 *
639 * This call must always succeed.
640 */
641void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num,
642 void *vaddr)
643{
644 WARN_ON(!dmabuf);
645
646 if (dmabuf->ops->kunmap)
647 dmabuf->ops->kunmap(dmabuf, page_num, vaddr);
648}
649EXPORT_SYMBOL_GPL(dma_buf_kunmap);
Daniel Vetter4c785132012-04-24 14:38:52 +0530650
651
652/**
653 * dma_buf_mmap - Setup up a userspace mmap with the given vma
Sumit Semwal12c47272012-05-23 15:27:40 +0530654 * @dmabuf: [in] buffer that should back the vma
Daniel Vetter4c785132012-04-24 14:38:52 +0530655 * @vma: [in] vma for the mmap
656 * @pgoff: [in] offset in pages where this mmap should start within the
Jagan Teki51366292015-05-21 01:09:31 +0530657 * dma-buf buffer.
Daniel Vetter4c785132012-04-24 14:38:52 +0530658 *
659 * This function adjusts the passed in vma so that it points at the file of the
Javier Martinez Canillasecf1dba2014-04-10 01:30:05 +0200660 * dma_buf operation. It also adjusts the starting pgoff and does bounds
Daniel Vetter4c785132012-04-24 14:38:52 +0530661 * checking on the size of the vma. Then it calls the exporters mmap function to
662 * set up the mapping.
663 *
664 * Can return negative error values, returns 0 on success.
665 */
666int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
667 unsigned long pgoff)
668{
John Sheu495c10c2013-02-11 17:50:24 -0800669 struct file *oldfile;
670 int ret;
671
Daniel Vetter4c785132012-04-24 14:38:52 +0530672 if (WARN_ON(!dmabuf || !vma))
673 return -EINVAL;
674
675 /* check for offset overflow */
676 if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) < pgoff)
677 return -EOVERFLOW;
678
679 /* check for overflowing the buffer's size */
680 if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
681 dmabuf->size >> PAGE_SHIFT)
682 return -EINVAL;
683
684 /* readjust the vma */
John Sheu495c10c2013-02-11 17:50:24 -0800685 get_file(dmabuf->file);
686 oldfile = vma->vm_file;
687 vma->vm_file = dmabuf->file;
Daniel Vetter4c785132012-04-24 14:38:52 +0530688 vma->vm_pgoff = pgoff;
689
John Sheu495c10c2013-02-11 17:50:24 -0800690 ret = dmabuf->ops->mmap(dmabuf, vma);
691 if (ret) {
692 /* restore old parameters on failure */
693 vma->vm_file = oldfile;
694 fput(dmabuf->file);
695 } else {
696 if (oldfile)
697 fput(oldfile);
698 }
699 return ret;
700
Daniel Vetter4c785132012-04-24 14:38:52 +0530701}
702EXPORT_SYMBOL_GPL(dma_buf_mmap);
Dave Airlie98f86c92012-05-20 12:33:56 +0530703
704/**
Sumit Semwal12c47272012-05-23 15:27:40 +0530705 * dma_buf_vmap - Create virtual mapping for the buffer object into kernel
706 * address space. Same restrictions as for vmap and friends apply.
707 * @dmabuf: [in] buffer to vmap
Dave Airlie98f86c92012-05-20 12:33:56 +0530708 *
709 * This call may fail due to lack of virtual mapping address space.
710 * These calls are optional in drivers. The intended use for them
711 * is for mapping objects linear in kernel space for high use objects.
712 * Please attempt to use kmap/kunmap before thinking about these interfaces.
Colin Crossfee0c542013-12-20 16:43:50 -0800713 *
714 * Returns NULL on error.
Dave Airlie98f86c92012-05-20 12:33:56 +0530715 */
716void *dma_buf_vmap(struct dma_buf *dmabuf)
717{
Daniel Vetterf00b4da2012-12-20 14:14:23 +0100718 void *ptr;
719
Dave Airlie98f86c92012-05-20 12:33:56 +0530720 if (WARN_ON(!dmabuf))
721 return NULL;
722
Daniel Vetterf00b4da2012-12-20 14:14:23 +0100723 if (!dmabuf->ops->vmap)
724 return NULL;
725
726 mutex_lock(&dmabuf->lock);
727 if (dmabuf->vmapping_counter) {
728 dmabuf->vmapping_counter++;
729 BUG_ON(!dmabuf->vmap_ptr);
730 ptr = dmabuf->vmap_ptr;
731 goto out_unlock;
732 }
733
734 BUG_ON(dmabuf->vmap_ptr);
735
736 ptr = dmabuf->ops->vmap(dmabuf);
Colin Crossfee0c542013-12-20 16:43:50 -0800737 if (WARN_ON_ONCE(IS_ERR(ptr)))
738 ptr = NULL;
739 if (!ptr)
Daniel Vetterf00b4da2012-12-20 14:14:23 +0100740 goto out_unlock;
741
742 dmabuf->vmap_ptr = ptr;
743 dmabuf->vmapping_counter = 1;
744
745out_unlock:
746 mutex_unlock(&dmabuf->lock);
747 return ptr;
Dave Airlie98f86c92012-05-20 12:33:56 +0530748}
749EXPORT_SYMBOL_GPL(dma_buf_vmap);
750
751/**
752 * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
Sumit Semwal12c47272012-05-23 15:27:40 +0530753 * @dmabuf: [in] buffer to vunmap
Randy Dunlap6e7b4a52012-06-09 15:02:59 -0700754 * @vaddr: [in] vmap to vunmap
Dave Airlie98f86c92012-05-20 12:33:56 +0530755 */
756void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
757{
758 if (WARN_ON(!dmabuf))
759 return;
760
Daniel Vetterf00b4da2012-12-20 14:14:23 +0100761 BUG_ON(!dmabuf->vmap_ptr);
762 BUG_ON(dmabuf->vmapping_counter == 0);
763 BUG_ON(dmabuf->vmap_ptr != vaddr);
764
765 mutex_lock(&dmabuf->lock);
766 if (--dmabuf->vmapping_counter == 0) {
767 if (dmabuf->ops->vunmap)
768 dmabuf->ops->vunmap(dmabuf, vaddr);
769 dmabuf->vmap_ptr = NULL;
770 }
771 mutex_unlock(&dmabuf->lock);
Dave Airlie98f86c92012-05-20 12:33:56 +0530772}
773EXPORT_SYMBOL_GPL(dma_buf_vunmap);
Sumit Semwalb89e3562013-04-04 11:44:37 +0530774
775#ifdef CONFIG_DEBUG_FS
776static int dma_buf_describe(struct seq_file *s)
777{
778 int ret;
779 struct dma_buf *buf_obj;
780 struct dma_buf_attachment *attach_obj;
781 int count = 0, attach_count;
782 size_t size = 0;
783
784 ret = mutex_lock_interruptible(&db_list.lock);
785
786 if (ret)
787 return ret;
788
Sumit Semwalc0b00a52014-02-03 15:09:12 +0530789 seq_puts(s, "\nDma-buf Objects:\n");
790 seq_puts(s, "size\tflags\tmode\tcount\texp_name\n");
Sumit Semwalb89e3562013-04-04 11:44:37 +0530791
792 list_for_each_entry(buf_obj, &db_list.head, list_node) {
793 ret = mutex_lock_interruptible(&buf_obj->lock);
794
795 if (ret) {
Sumit Semwalc0b00a52014-02-03 15:09:12 +0530796 seq_puts(s,
797 "\tERROR locking buffer object: skipping\n");
Sumit Semwalb89e3562013-04-04 11:44:37 +0530798 continue;
799 }
800
Sumit Semwalc0b00a52014-02-03 15:09:12 +0530801 seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\n",
802 buf_obj->size,
Sumit Semwalb89e3562013-04-04 11:44:37 +0530803 buf_obj->file->f_flags, buf_obj->file->f_mode,
Al Viroa1f6dba2014-08-20 11:05:50 -0400804 file_count(buf_obj->file),
Sumit Semwalc0b00a52014-02-03 15:09:12 +0530805 buf_obj->exp_name);
Sumit Semwalb89e3562013-04-04 11:44:37 +0530806
Sumit Semwalc0b00a52014-02-03 15:09:12 +0530807 seq_puts(s, "\tAttached Devices:\n");
Sumit Semwalb89e3562013-04-04 11:44:37 +0530808 attach_count = 0;
809
810 list_for_each_entry(attach_obj, &buf_obj->attachments, node) {
Sumit Semwalc0b00a52014-02-03 15:09:12 +0530811 seq_puts(s, "\t");
Sumit Semwalb89e3562013-04-04 11:44:37 +0530812
Sumit Semwalc0b00a52014-02-03 15:09:12 +0530813 seq_printf(s, "%s\n", dev_name(attach_obj->dev));
Sumit Semwalb89e3562013-04-04 11:44:37 +0530814 attach_count++;
815 }
816
Sumit Semwalc0b00a52014-02-03 15:09:12 +0530817 seq_printf(s, "Total %d devices attached\n\n",
Sumit Semwalb89e3562013-04-04 11:44:37 +0530818 attach_count);
819
820 count++;
821 size += buf_obj->size;
822 mutex_unlock(&buf_obj->lock);
823 }
824
825 seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size);
826
827 mutex_unlock(&db_list.lock);
828 return 0;
829}
830
831static int dma_buf_show(struct seq_file *s, void *unused)
832{
833 void (*func)(struct seq_file *) = s->private;
Jagan Teki51366292015-05-21 01:09:31 +0530834
Sumit Semwalb89e3562013-04-04 11:44:37 +0530835 func(s);
836 return 0;
837}
838
839static int dma_buf_debug_open(struct inode *inode, struct file *file)
840{
841 return single_open(file, dma_buf_show, inode->i_private);
842}
843
844static const struct file_operations dma_buf_debug_fops = {
845 .open = dma_buf_debug_open,
846 .read = seq_read,
847 .llseek = seq_lseek,
848 .release = single_release,
849};
850
851static struct dentry *dma_buf_debugfs_dir;
852
853static int dma_buf_init_debugfs(void)
854{
855 int err = 0;
Jagan Teki51366292015-05-21 01:09:31 +0530856
Sumit Semwalb89e3562013-04-04 11:44:37 +0530857 dma_buf_debugfs_dir = debugfs_create_dir("dma_buf", NULL);
Jagan Teki51366292015-05-21 01:09:31 +0530858
Sumit Semwalb89e3562013-04-04 11:44:37 +0530859 if (IS_ERR(dma_buf_debugfs_dir)) {
860 err = PTR_ERR(dma_buf_debugfs_dir);
861 dma_buf_debugfs_dir = NULL;
862 return err;
863 }
864
865 err = dma_buf_debugfs_create_file("bufinfo", dma_buf_describe);
866
867 if (err)
868 pr_debug("dma_buf: debugfs: failed to create node bufinfo\n");
869
870 return err;
871}
872
873static void dma_buf_uninit_debugfs(void)
874{
875 if (dma_buf_debugfs_dir)
876 debugfs_remove_recursive(dma_buf_debugfs_dir);
877}
878
879int dma_buf_debugfs_create_file(const char *name,
880 int (*write)(struct seq_file *))
881{
882 struct dentry *d;
883
884 d = debugfs_create_file(name, S_IRUGO, dma_buf_debugfs_dir,
885 write, &dma_buf_debug_fops);
886
Sachin Kamat28ce4202013-07-15 15:51:22 +0530887 return PTR_ERR_OR_ZERO(d);
Sumit Semwalb89e3562013-04-04 11:44:37 +0530888}
889#else
890static inline int dma_buf_init_debugfs(void)
891{
892 return 0;
893}
894static inline void dma_buf_uninit_debugfs(void)
895{
896}
897#endif
898
899static int __init dma_buf_init(void)
900{
901 mutex_init(&db_list.lock);
902 INIT_LIST_HEAD(&db_list.head);
903 dma_buf_init_debugfs();
904 return 0;
905}
906subsys_initcall(dma_buf_init);
907
908static void __exit dma_buf_deinit(void)
909{
910 dma_buf_uninit_debugfs();
911}
912__exitcall(dma_buf_deinit);