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Commit | Line | Data |
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d15bd7ee SS |
1 | /* |
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> | |
f54d1867 | 28 | #include <linux/dma-fence.h> |
d15bd7ee SS |
29 | #include <linux/anon_inodes.h> |
30 | #include <linux/export.h> | |
b89e3563 | 31 | #include <linux/debugfs.h> |
9abdffe2 | 32 | #include <linux/module.h> |
b89e3563 | 33 | #include <linux/seq_file.h> |
9b495a58 | 34 | #include <linux/poll.h> |
3aac4502 | 35 | #include <linux/reservation.h> |
b02da6f8 | 36 | #include <linux/mm.h> |
d15bd7ee | 37 | |
c11e391d DV |
38 | #include <uapi/linux/dma-buf.h> |
39 | ||
d15bd7ee SS |
40 | static inline int is_dma_buf_file(struct file *); |
41 | ||
b89e3563 SS |
42 | struct dma_buf_list { |
43 | struct list_head head; | |
44 | struct mutex lock; | |
45 | }; | |
46 | ||
47 | static struct dma_buf_list db_list; | |
48 | ||
d15bd7ee SS |
49 | static int dma_buf_release(struct inode *inode, struct file *file) |
50 | { | |
51 | struct dma_buf *dmabuf; | |
52 | ||
53 | if (!is_dma_buf_file(file)) | |
54 | return -EINVAL; | |
55 | ||
56 | dmabuf = file->private_data; | |
57 | ||
f00b4dad DV |
58 | BUG_ON(dmabuf->vmapping_counter); |
59 | ||
9b495a58 ML |
60 | /* |
61 | * Any fences that a dma-buf poll can wait on should be signaled | |
62 | * before releasing dma-buf. This is the responsibility of each | |
63 | * driver that uses the reservation objects. | |
64 | * | |
65 | * If you hit this BUG() it means someone dropped their ref to the | |
66 | * dma-buf while still having pending operation to the buffer. | |
67 | */ | |
68 | BUG_ON(dmabuf->cb_shared.active || dmabuf->cb_excl.active); | |
69 | ||
d15bd7ee | 70 | dmabuf->ops->release(dmabuf); |
b89e3563 SS |
71 | |
72 | mutex_lock(&db_list.lock); | |
73 | list_del(&dmabuf->list_node); | |
74 | mutex_unlock(&db_list.lock); | |
75 | ||
3aac4502 ML |
76 | if (dmabuf->resv == (struct reservation_object *)&dmabuf[1]) |
77 | reservation_object_fini(dmabuf->resv); | |
78 | ||
9abdffe2 | 79 | module_put(dmabuf->owner); |
d15bd7ee SS |
80 | kfree(dmabuf); |
81 | return 0; | |
82 | } | |
83 | ||
4c78513e DV |
84 | static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) |
85 | { | |
86 | struct dma_buf *dmabuf; | |
87 | ||
88 | if (!is_dma_buf_file(file)) | |
89 | return -EINVAL; | |
90 | ||
91 | dmabuf = file->private_data; | |
92 | ||
93 | /* check for overflowing the buffer's size */ | |
b02da6f8 | 94 | if (vma->vm_pgoff + vma_pages(vma) > |
4c78513e DV |
95 | dmabuf->size >> PAGE_SHIFT) |
96 | return -EINVAL; | |
97 | ||
98 | return dmabuf->ops->mmap(dmabuf, vma); | |
99 | } | |
100 | ||
19e8697b CJHR |
101 | static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence) |
102 | { | |
103 | struct dma_buf *dmabuf; | |
104 | loff_t base; | |
105 | ||
106 | if (!is_dma_buf_file(file)) | |
107 | return -EBADF; | |
108 | ||
109 | dmabuf = file->private_data; | |
110 | ||
111 | /* only support discovering the end of the buffer, | |
112 | but also allow SEEK_SET to maintain the idiomatic | |
113 | SEEK_END(0), SEEK_CUR(0) pattern */ | |
114 | if (whence == SEEK_END) | |
115 | base = dmabuf->size; | |
116 | else if (whence == SEEK_SET) | |
117 | base = 0; | |
118 | else | |
119 | return -EINVAL; | |
120 | ||
121 | if (offset != 0) | |
122 | return -EINVAL; | |
123 | ||
124 | return base + offset; | |
125 | } | |
126 | ||
e7e21c72 DV |
127 | /** |
128 | * DOC: fence polling | |
129 | * | |
130 | * To support cross-device and cross-driver synchronization of buffer access | |
f641d3b5 | 131 | * implicit fences (represented internally in the kernel with &struct fence) can |
e7e21c72 DV |
132 | * be attached to a &dma_buf. The glue for that and a few related things are |
133 | * provided in the &reservation_object structure. | |
134 | * | |
135 | * Userspace can query the state of these implicitly tracked fences using poll() | |
136 | * and related system calls: | |
137 | * | |
138 | * - Checking for POLLIN, i.e. read access, can be use to query the state of the | |
139 | * most recent write or exclusive fence. | |
140 | * | |
141 | * - Checking for POLLOUT, i.e. write access, can be used to query the state of | |
142 | * all attached fences, shared and exclusive ones. | |
143 | * | |
144 | * Note that this only signals the completion of the respective fences, i.e. the | |
145 | * DMA transfers are complete. Cache flushing and any other necessary | |
146 | * preparations before CPU access can begin still need to happen. | |
147 | */ | |
148 | ||
f54d1867 | 149 | static void dma_buf_poll_cb(struct dma_fence *fence, struct dma_fence_cb *cb) |
9b495a58 ML |
150 | { |
151 | struct dma_buf_poll_cb_t *dcb = (struct dma_buf_poll_cb_t *)cb; | |
152 | unsigned long flags; | |
153 | ||
154 | spin_lock_irqsave(&dcb->poll->lock, flags); | |
155 | wake_up_locked_poll(dcb->poll, dcb->active); | |
156 | dcb->active = 0; | |
157 | spin_unlock_irqrestore(&dcb->poll->lock, flags); | |
158 | } | |
159 | ||
160 | static unsigned int dma_buf_poll(struct file *file, poll_table *poll) | |
161 | { | |
162 | struct dma_buf *dmabuf; | |
163 | struct reservation_object *resv; | |
04a5faa8 | 164 | struct reservation_object_list *fobj; |
f54d1867 | 165 | struct dma_fence *fence_excl; |
9b495a58 | 166 | unsigned long events; |
3c3b177a | 167 | unsigned shared_count, seq; |
9b495a58 ML |
168 | |
169 | dmabuf = file->private_data; | |
170 | if (!dmabuf || !dmabuf->resv) | |
171 | return POLLERR; | |
172 | ||
173 | resv = dmabuf->resv; | |
174 | ||
175 | poll_wait(file, &dmabuf->poll, poll); | |
176 | ||
177 | events = poll_requested_events(poll) & (POLLIN | POLLOUT); | |
178 | if (!events) | |
179 | return 0; | |
180 | ||
3c3b177a ML |
181 | retry: |
182 | seq = read_seqcount_begin(&resv->seq); | |
183 | rcu_read_lock(); | |
9b495a58 | 184 | |
3c3b177a ML |
185 | fobj = rcu_dereference(resv->fence); |
186 | if (fobj) | |
187 | shared_count = fobj->shared_count; | |
188 | else | |
189 | shared_count = 0; | |
190 | fence_excl = rcu_dereference(resv->fence_excl); | |
191 | if (read_seqcount_retry(&resv->seq, seq)) { | |
192 | rcu_read_unlock(); | |
193 | goto retry; | |
194 | } | |
04a5faa8 ML |
195 | |
196 | if (fence_excl && (!(events & POLLOUT) || shared_count == 0)) { | |
9b495a58 ML |
197 | struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_excl; |
198 | unsigned long pevents = POLLIN; | |
199 | ||
04a5faa8 | 200 | if (shared_count == 0) |
9b495a58 ML |
201 | pevents |= POLLOUT; |
202 | ||
203 | spin_lock_irq(&dmabuf->poll.lock); | |
204 | if (dcb->active) { | |
205 | dcb->active |= pevents; | |
206 | events &= ~pevents; | |
207 | } else | |
208 | dcb->active = pevents; | |
209 | spin_unlock_irq(&dmabuf->poll.lock); | |
210 | ||
211 | if (events & pevents) { | |
f54d1867 | 212 | if (!dma_fence_get_rcu(fence_excl)) { |
3c3b177a ML |
213 | /* force a recheck */ |
214 | events &= ~pevents; | |
215 | dma_buf_poll_cb(NULL, &dcb->cb); | |
f54d1867 CW |
216 | } else if (!dma_fence_add_callback(fence_excl, &dcb->cb, |
217 | dma_buf_poll_cb)) { | |
9b495a58 | 218 | events &= ~pevents; |
f54d1867 | 219 | dma_fence_put(fence_excl); |
04a5faa8 | 220 | } else { |
9b495a58 ML |
221 | /* |
222 | * No callback queued, wake up any additional | |
223 | * waiters. | |
224 | */ | |
f54d1867 | 225 | dma_fence_put(fence_excl); |
9b495a58 | 226 | dma_buf_poll_cb(NULL, &dcb->cb); |
04a5faa8 | 227 | } |
9b495a58 ML |
228 | } |
229 | } | |
230 | ||
04a5faa8 | 231 | if ((events & POLLOUT) && shared_count > 0) { |
9b495a58 ML |
232 | struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_shared; |
233 | int i; | |
234 | ||
235 | /* Only queue a new callback if no event has fired yet */ | |
236 | spin_lock_irq(&dmabuf->poll.lock); | |
237 | if (dcb->active) | |
238 | events &= ~POLLOUT; | |
239 | else | |
240 | dcb->active = POLLOUT; | |
241 | spin_unlock_irq(&dmabuf->poll.lock); | |
242 | ||
243 | if (!(events & POLLOUT)) | |
244 | goto out; | |
245 | ||
04a5faa8 | 246 | for (i = 0; i < shared_count; ++i) { |
f54d1867 | 247 | struct dma_fence *fence = rcu_dereference(fobj->shared[i]); |
04a5faa8 | 248 | |
f54d1867 | 249 | if (!dma_fence_get_rcu(fence)) { |
3c3b177a ML |
250 | /* |
251 | * fence refcount dropped to zero, this means | |
252 | * that fobj has been freed | |
253 | * | |
254 | * call dma_buf_poll_cb and force a recheck! | |
255 | */ | |
256 | events &= ~POLLOUT; | |
257 | dma_buf_poll_cb(NULL, &dcb->cb); | |
258 | break; | |
259 | } | |
f54d1867 CW |
260 | if (!dma_fence_add_callback(fence, &dcb->cb, |
261 | dma_buf_poll_cb)) { | |
262 | dma_fence_put(fence); | |
9b495a58 ML |
263 | events &= ~POLLOUT; |
264 | break; | |
265 | } | |
f54d1867 | 266 | dma_fence_put(fence); |
04a5faa8 | 267 | } |
9b495a58 ML |
268 | |
269 | /* No callback queued, wake up any additional waiters. */ | |
04a5faa8 | 270 | if (i == shared_count) |
9b495a58 ML |
271 | dma_buf_poll_cb(NULL, &dcb->cb); |
272 | } | |
273 | ||
274 | out: | |
3c3b177a | 275 | rcu_read_unlock(); |
9b495a58 ML |
276 | return events; |
277 | } | |
278 | ||
c11e391d DV |
279 | static long dma_buf_ioctl(struct file *file, |
280 | unsigned int cmd, unsigned long arg) | |
281 | { | |
282 | struct dma_buf *dmabuf; | |
283 | struct dma_buf_sync sync; | |
284 | enum dma_data_direction direction; | |
18b862dc | 285 | int ret; |
c11e391d DV |
286 | |
287 | dmabuf = file->private_data; | |
288 | ||
289 | switch (cmd) { | |
290 | case DMA_BUF_IOCTL_SYNC: | |
291 | if (copy_from_user(&sync, (void __user *) arg, sizeof(sync))) | |
292 | return -EFAULT; | |
293 | ||
294 | if (sync.flags & ~DMA_BUF_SYNC_VALID_FLAGS_MASK) | |
295 | return -EINVAL; | |
296 | ||
297 | switch (sync.flags & DMA_BUF_SYNC_RW) { | |
298 | case DMA_BUF_SYNC_READ: | |
299 | direction = DMA_FROM_DEVICE; | |
300 | break; | |
301 | case DMA_BUF_SYNC_WRITE: | |
302 | direction = DMA_TO_DEVICE; | |
303 | break; | |
304 | case DMA_BUF_SYNC_RW: | |
305 | direction = DMA_BIDIRECTIONAL; | |
306 | break; | |
307 | default: | |
308 | return -EINVAL; | |
309 | } | |
310 | ||
311 | if (sync.flags & DMA_BUF_SYNC_END) | |
18b862dc | 312 | ret = dma_buf_end_cpu_access(dmabuf, direction); |
c11e391d | 313 | else |
18b862dc | 314 | ret = dma_buf_begin_cpu_access(dmabuf, direction); |
c11e391d | 315 | |
18b862dc | 316 | return ret; |
c11e391d DV |
317 | default: |
318 | return -ENOTTY; | |
319 | } | |
320 | } | |
321 | ||
d15bd7ee SS |
322 | static const struct file_operations dma_buf_fops = { |
323 | .release = dma_buf_release, | |
4c78513e | 324 | .mmap = dma_buf_mmap_internal, |
19e8697b | 325 | .llseek = dma_buf_llseek, |
9b495a58 | 326 | .poll = dma_buf_poll, |
c11e391d | 327 | .unlocked_ioctl = dma_buf_ioctl, |
888022c0 MS |
328 | #ifdef CONFIG_COMPAT |
329 | .compat_ioctl = dma_buf_ioctl, | |
330 | #endif | |
d15bd7ee SS |
331 | }; |
332 | ||
333 | /* | |
334 | * is_dma_buf_file - Check if struct file* is associated with dma_buf | |
335 | */ | |
336 | static inline int is_dma_buf_file(struct file *file) | |
337 | { | |
338 | return file->f_op == &dma_buf_fops; | |
339 | } | |
340 | ||
2904a8c1 DV |
341 | /** |
342 | * DOC: dma buf device access | |
343 | * | |
344 | * For device DMA access to a shared DMA buffer the usual sequence of operations | |
345 | * is fairly simple: | |
346 | * | |
347 | * 1. The exporter defines his exporter instance using | |
348 | * DEFINE_DMA_BUF_EXPORT_INFO() and calls dma_buf_export() to wrap a private | |
349 | * buffer object into a &dma_buf. It then exports that &dma_buf to userspace | |
350 | * as a file descriptor by calling dma_buf_fd(). | |
351 | * | |
352 | * 2. Userspace passes this file-descriptors to all drivers it wants this buffer | |
353 | * to share with: First the filedescriptor is converted to a &dma_buf using | |
354 | * dma_buf_get(). The the buffer is attached to the device using | |
355 | * dma_buf_attach(). | |
356 | * | |
357 | * Up to this stage the exporter is still free to migrate or reallocate the | |
358 | * backing storage. | |
359 | * | |
360 | * 3. Once the buffer is attached to all devices userspace can inniate DMA | |
361 | * access to the shared buffer. In the kernel this is done by calling | |
362 | * dma_buf_map_attachment() and dma_buf_unmap_attachment(). | |
363 | * | |
364 | * 4. Once a driver is done with a shared buffer it needs to call | |
365 | * dma_buf_detach() (after cleaning up any mappings) and then release the | |
366 | * reference acquired with dma_buf_get by calling dma_buf_put(). | |
367 | * | |
368 | * For the detailed semantics exporters are expected to implement see | |
369 | * &dma_buf_ops. | |
370 | */ | |
371 | ||
d15bd7ee | 372 | /** |
d8fbe341 | 373 | * dma_buf_export - Creates a new dma_buf, and associates an anon file |
d15bd7ee SS |
374 | * with this buffer, so it can be exported. |
375 | * Also connect the allocator specific data and ops to the buffer. | |
78df9695 | 376 | * Additionally, provide a name string for exporter; useful in debugging. |
d15bd7ee | 377 | * |
d8fbe341 | 378 | * @exp_info: [in] holds all the export related information provided |
f641d3b5 | 379 | * by the exporter. see &struct dma_buf_export_info |
d8fbe341 | 380 | * for further details. |
d15bd7ee SS |
381 | * |
382 | * Returns, on success, a newly created dma_buf object, which wraps the | |
383 | * supplied private data and operations for dma_buf_ops. On either missing | |
384 | * ops, or error in allocating struct dma_buf, will return negative error. | |
385 | * | |
2904a8c1 DV |
386 | * For most cases the easiest way to create @exp_info is through the |
387 | * %DEFINE_DMA_BUF_EXPORT_INFO macro. | |
d15bd7ee | 388 | */ |
d8fbe341 | 389 | struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) |
d15bd7ee SS |
390 | { |
391 | struct dma_buf *dmabuf; | |
d8fbe341 | 392 | struct reservation_object *resv = exp_info->resv; |
d15bd7ee | 393 | struct file *file; |
3aac4502 | 394 | size_t alloc_size = sizeof(struct dma_buf); |
a026df4c | 395 | int ret; |
5136629d | 396 | |
d8fbe341 | 397 | if (!exp_info->resv) |
3aac4502 ML |
398 | alloc_size += sizeof(struct reservation_object); |
399 | else | |
400 | /* prevent &dma_buf[1] == dma_buf->resv */ | |
401 | alloc_size += 1; | |
d15bd7ee | 402 | |
d8fbe341 SS |
403 | if (WARN_ON(!exp_info->priv |
404 | || !exp_info->ops | |
405 | || !exp_info->ops->map_dma_buf | |
406 | || !exp_info->ops->unmap_dma_buf | |
407 | || !exp_info->ops->release | |
408 | || !exp_info->ops->kmap_atomic | |
409 | || !exp_info->ops->kmap | |
410 | || !exp_info->ops->mmap)) { | |
d15bd7ee SS |
411 | return ERR_PTR(-EINVAL); |
412 | } | |
413 | ||
9abdffe2 SS |
414 | if (!try_module_get(exp_info->owner)) |
415 | return ERR_PTR(-ENOENT); | |
416 | ||
3aac4502 | 417 | dmabuf = kzalloc(alloc_size, GFP_KERNEL); |
9abdffe2 | 418 | if (!dmabuf) { |
a026df4c CW |
419 | ret = -ENOMEM; |
420 | goto err_module; | |
9abdffe2 | 421 | } |
d15bd7ee | 422 | |
d8fbe341 SS |
423 | dmabuf->priv = exp_info->priv; |
424 | dmabuf->ops = exp_info->ops; | |
425 | dmabuf->size = exp_info->size; | |
426 | dmabuf->exp_name = exp_info->exp_name; | |
9abdffe2 | 427 | dmabuf->owner = exp_info->owner; |
9b495a58 ML |
428 | init_waitqueue_head(&dmabuf->poll); |
429 | dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll; | |
430 | dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0; | |
431 | ||
3aac4502 ML |
432 | if (!resv) { |
433 | resv = (struct reservation_object *)&dmabuf[1]; | |
434 | reservation_object_init(resv); | |
435 | } | |
436 | dmabuf->resv = resv; | |
d15bd7ee | 437 | |
d8fbe341 SS |
438 | file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, |
439 | exp_info->flags); | |
9022e24e | 440 | if (IS_ERR(file)) { |
a026df4c CW |
441 | ret = PTR_ERR(file); |
442 | goto err_dmabuf; | |
9022e24e | 443 | } |
19e8697b CJHR |
444 | |
445 | file->f_mode |= FMODE_LSEEK; | |
d15bd7ee SS |
446 | dmabuf->file = file; |
447 | ||
448 | mutex_init(&dmabuf->lock); | |
449 | INIT_LIST_HEAD(&dmabuf->attachments); | |
450 | ||
b89e3563 SS |
451 | mutex_lock(&db_list.lock); |
452 | list_add(&dmabuf->list_node, &db_list.head); | |
453 | mutex_unlock(&db_list.lock); | |
454 | ||
d15bd7ee | 455 | return dmabuf; |
a026df4c CW |
456 | |
457 | err_dmabuf: | |
458 | kfree(dmabuf); | |
459 | err_module: | |
460 | module_put(exp_info->owner); | |
461 | return ERR_PTR(ret); | |
d15bd7ee | 462 | } |
d8fbe341 | 463 | EXPORT_SYMBOL_GPL(dma_buf_export); |
d15bd7ee SS |
464 | |
465 | /** | |
466 | * dma_buf_fd - returns a file descriptor for the given dma_buf | |
467 | * @dmabuf: [in] pointer to dma_buf for which fd is required. | |
55c1c4ca | 468 | * @flags: [in] flags to give to fd |
d15bd7ee SS |
469 | * |
470 | * On success, returns an associated 'fd'. Else, returns error. | |
471 | */ | |
55c1c4ca | 472 | int dma_buf_fd(struct dma_buf *dmabuf, int flags) |
d15bd7ee | 473 | { |
f5e097f0 | 474 | int fd; |
d15bd7ee SS |
475 | |
476 | if (!dmabuf || !dmabuf->file) | |
477 | return -EINVAL; | |
478 | ||
f5e097f0 BP |
479 | fd = get_unused_fd_flags(flags); |
480 | if (fd < 0) | |
481 | return fd; | |
d15bd7ee SS |
482 | |
483 | fd_install(fd, dmabuf->file); | |
484 | ||
485 | return fd; | |
486 | } | |
487 | EXPORT_SYMBOL_GPL(dma_buf_fd); | |
488 | ||
489 | /** | |
490 | * dma_buf_get - returns the dma_buf structure related to an fd | |
491 | * @fd: [in] fd associated with the dma_buf to be returned | |
492 | * | |
493 | * On success, returns the dma_buf structure associated with an fd; uses | |
494 | * file's refcounting done by fget to increase refcount. returns ERR_PTR | |
495 | * otherwise. | |
496 | */ | |
497 | struct dma_buf *dma_buf_get(int fd) | |
498 | { | |
499 | struct file *file; | |
500 | ||
501 | file = fget(fd); | |
502 | ||
503 | if (!file) | |
504 | return ERR_PTR(-EBADF); | |
505 | ||
506 | if (!is_dma_buf_file(file)) { | |
507 | fput(file); | |
508 | return ERR_PTR(-EINVAL); | |
509 | } | |
510 | ||
511 | return file->private_data; | |
512 | } | |
513 | EXPORT_SYMBOL_GPL(dma_buf_get); | |
514 | ||
515 | /** | |
516 | * dma_buf_put - decreases refcount of the buffer | |
517 | * @dmabuf: [in] buffer to reduce refcount of | |
518 | * | |
2904a8c1 DV |
519 | * Uses file's refcounting done implicitly by fput(). |
520 | * | |
521 | * If, as a result of this call, the refcount becomes 0, the 'release' file | |
e9b4d7b5 DV |
522 | * operation related to this fd is called. It calls &dma_buf_ops.release vfunc |
523 | * in turn, and frees the memory allocated for dmabuf when exported. | |
d15bd7ee SS |
524 | */ |
525 | void dma_buf_put(struct dma_buf *dmabuf) | |
526 | { | |
527 | if (WARN_ON(!dmabuf || !dmabuf->file)) | |
528 | return; | |
529 | ||
530 | fput(dmabuf->file); | |
531 | } | |
532 | EXPORT_SYMBOL_GPL(dma_buf_put); | |
533 | ||
534 | /** | |
535 | * dma_buf_attach - Add the device to dma_buf's attachments list; optionally, | |
536 | * calls attach() of dma_buf_ops to allow device-specific attach functionality | |
537 | * @dmabuf: [in] buffer to attach device to. | |
538 | * @dev: [in] device to be attached. | |
539 | * | |
2904a8c1 DV |
540 | * Returns struct dma_buf_attachment pointer for this attachment. Attachments |
541 | * must be cleaned up by calling dma_buf_detach(). | |
542 | * | |
543 | * Returns: | |
544 | * | |
545 | * A pointer to newly created &dma_buf_attachment on success, or a negative | |
546 | * error code wrapped into a pointer on failure. | |
547 | * | |
548 | * Note that this can fail if the backing storage of @dmabuf is in a place not | |
549 | * accessible to @dev, and cannot be moved to a more suitable place. This is | |
550 | * indicated with the error code -EBUSY. | |
d15bd7ee SS |
551 | */ |
552 | struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, | |
553 | struct device *dev) | |
554 | { | |
555 | struct dma_buf_attachment *attach; | |
556 | int ret; | |
557 | ||
d1aa06a1 | 558 | if (WARN_ON(!dmabuf || !dev)) |
d15bd7ee SS |
559 | return ERR_PTR(-EINVAL); |
560 | ||
561 | attach = kzalloc(sizeof(struct dma_buf_attachment), GFP_KERNEL); | |
562 | if (attach == NULL) | |
a9fbc3b7 | 563 | return ERR_PTR(-ENOMEM); |
d15bd7ee | 564 | |
d15bd7ee SS |
565 | attach->dev = dev; |
566 | attach->dmabuf = dmabuf; | |
2ed9201b LP |
567 | |
568 | mutex_lock(&dmabuf->lock); | |
569 | ||
d15bd7ee SS |
570 | if (dmabuf->ops->attach) { |
571 | ret = dmabuf->ops->attach(dmabuf, dev, attach); | |
572 | if (ret) | |
573 | goto err_attach; | |
574 | } | |
575 | list_add(&attach->node, &dmabuf->attachments); | |
576 | ||
577 | mutex_unlock(&dmabuf->lock); | |
578 | return attach; | |
579 | ||
d15bd7ee SS |
580 | err_attach: |
581 | kfree(attach); | |
582 | mutex_unlock(&dmabuf->lock); | |
583 | return ERR_PTR(ret); | |
584 | } | |
585 | EXPORT_SYMBOL_GPL(dma_buf_attach); | |
586 | ||
587 | /** | |
588 | * dma_buf_detach - Remove the given attachment from dmabuf's attachments list; | |
589 | * optionally calls detach() of dma_buf_ops for device-specific detach | |
590 | * @dmabuf: [in] buffer to detach from. | |
591 | * @attach: [in] attachment to be detached; is free'd after this call. | |
592 | * | |
2904a8c1 | 593 | * Clean up a device attachment obtained by calling dma_buf_attach(). |
d15bd7ee SS |
594 | */ |
595 | void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) | |
596 | { | |
d1aa06a1 | 597 | if (WARN_ON(!dmabuf || !attach)) |
d15bd7ee SS |
598 | return; |
599 | ||
600 | mutex_lock(&dmabuf->lock); | |
601 | list_del(&attach->node); | |
602 | if (dmabuf->ops->detach) | |
603 | dmabuf->ops->detach(dmabuf, attach); | |
604 | ||
605 | mutex_unlock(&dmabuf->lock); | |
606 | kfree(attach); | |
607 | } | |
608 | EXPORT_SYMBOL_GPL(dma_buf_detach); | |
609 | ||
610 | /** | |
611 | * dma_buf_map_attachment - Returns the scatterlist table of the attachment; | |
612 | * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the | |
613 | * dma_buf_ops. | |
614 | * @attach: [in] attachment whose scatterlist is to be returned | |
615 | * @direction: [in] direction of DMA transfer | |
616 | * | |
fee0c54e | 617 | * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR |
2904a8c1 DV |
618 | * on error. May return -EINTR if it is interrupted by a signal. |
619 | * | |
620 | * A mapping must be unmapped again using dma_buf_map_attachment(). Note that | |
621 | * the underlying backing storage is pinned for as long as a mapping exists, | |
622 | * therefore users/importers should not hold onto a mapping for undue amounts of | |
623 | * time. | |
d15bd7ee SS |
624 | */ |
625 | struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, | |
626 | enum dma_data_direction direction) | |
627 | { | |
628 | struct sg_table *sg_table = ERR_PTR(-EINVAL); | |
629 | ||
630 | might_sleep(); | |
631 | ||
d1aa06a1 | 632 | if (WARN_ON(!attach || !attach->dmabuf)) |
d15bd7ee SS |
633 | return ERR_PTR(-EINVAL); |
634 | ||
d1aa06a1 | 635 | sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction); |
fee0c54e CC |
636 | if (!sg_table) |
637 | sg_table = ERR_PTR(-ENOMEM); | |
d15bd7ee SS |
638 | |
639 | return sg_table; | |
640 | } | |
641 | EXPORT_SYMBOL_GPL(dma_buf_map_attachment); | |
642 | ||
643 | /** | |
644 | * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might | |
645 | * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of | |
646 | * dma_buf_ops. | |
647 | * @attach: [in] attachment to unmap buffer from | |
648 | * @sg_table: [in] scatterlist info of the buffer to unmap | |
33ea2dcb | 649 | * @direction: [in] direction of DMA transfer |
d15bd7ee | 650 | * |
2904a8c1 | 651 | * This unmaps a DMA mapping for @attached obtained by dma_buf_map_attachment(). |
d15bd7ee SS |
652 | */ |
653 | void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, | |
33ea2dcb SS |
654 | struct sg_table *sg_table, |
655 | enum dma_data_direction direction) | |
d15bd7ee | 656 | { |
b6fa0cd6 RC |
657 | might_sleep(); |
658 | ||
d1aa06a1 | 659 | if (WARN_ON(!attach || !attach->dmabuf || !sg_table)) |
d15bd7ee SS |
660 | return; |
661 | ||
33ea2dcb SS |
662 | attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, |
663 | direction); | |
d15bd7ee SS |
664 | } |
665 | EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment); | |
fc13020e | 666 | |
0959a168 DV |
667 | /** |
668 | * DOC: cpu access | |
669 | * | |
670 | * There are mutliple reasons for supporting CPU access to a dma buffer object: | |
671 | * | |
672 | * - Fallback operations in the kernel, for example when a device is connected | |
673 | * over USB and the kernel needs to shuffle the data around first before | |
674 | * sending it away. Cache coherency is handled by braketing any transactions | |
675 | * with calls to dma_buf_begin_cpu_access() and dma_buf_end_cpu_access() | |
676 | * access. | |
677 | * | |
678 | * To support dma_buf objects residing in highmem cpu access is page-based | |
679 | * using an api similar to kmap. Accessing a dma_buf is done in aligned chunks | |
680 | * of PAGE_SIZE size. Before accessing a chunk it needs to be mapped, which | |
681 | * returns a pointer in kernel virtual address space. Afterwards the chunk | |
682 | * needs to be unmapped again. There is no limit on how often a given chunk | |
683 | * can be mapped and unmapped, i.e. the importer does not need to call | |
684 | * begin_cpu_access again before mapping the same chunk again. | |
685 | * | |
686 | * Interfaces:: | |
687 | * void \*dma_buf_kmap(struct dma_buf \*, unsigned long); | |
688 | * void dma_buf_kunmap(struct dma_buf \*, unsigned long, void \*); | |
689 | * | |
690 | * There are also atomic variants of these interfaces. Like for kmap they | |
691 | * facilitate non-blocking fast-paths. Neither the importer nor the exporter | |
692 | * (in the callback) is allowed to block when using these. | |
693 | * | |
694 | * Interfaces:: | |
695 | * void \*dma_buf_kmap_atomic(struct dma_buf \*, unsigned long); | |
696 | * void dma_buf_kunmap_atomic(struct dma_buf \*, unsigned long, void \*); | |
697 | * | |
698 | * For importers all the restrictions of using kmap apply, like the limited | |
699 | * supply of kmap_atomic slots. Hence an importer shall only hold onto at | |
700 | * max 2 atomic dma_buf kmaps at the same time (in any given process context). | |
701 | * | |
702 | * dma_buf kmap calls outside of the range specified in begin_cpu_access are | |
703 | * undefined. If the range is not PAGE_SIZE aligned, kmap needs to succeed on | |
704 | * the partial chunks at the beginning and end but may return stale or bogus | |
705 | * data outside of the range (in these partial chunks). | |
706 | * | |
707 | * Note that these calls need to always succeed. The exporter needs to | |
708 | * complete any preparations that might fail in begin_cpu_access. | |
709 | * | |
710 | * For some cases the overhead of kmap can be too high, a vmap interface | |
711 | * is introduced. This interface should be used very carefully, as vmalloc | |
712 | * space is a limited resources on many architectures. | |
713 | * | |
714 | * Interfaces:: | |
715 | * void \*dma_buf_vmap(struct dma_buf \*dmabuf) | |
716 | * void dma_buf_vunmap(struct dma_buf \*dmabuf, void \*vaddr) | |
717 | * | |
718 | * The vmap call can fail if there is no vmap support in the exporter, or if | |
719 | * it runs out of vmalloc space. Fallback to kmap should be implemented. Note | |
720 | * that the dma-buf layer keeps a reference count for all vmap access and | |
721 | * calls down into the exporter's vmap function only when no vmapping exists, | |
722 | * and only unmaps it once. Protection against concurrent vmap/vunmap calls is | |
723 | * provided by taking the dma_buf->lock mutex. | |
724 | * | |
725 | * - For full compatibility on the importer side with existing userspace | |
726 | * interfaces, which might already support mmap'ing buffers. This is needed in | |
727 | * many processing pipelines (e.g. feeding a software rendered image into a | |
728 | * hardware pipeline, thumbnail creation, snapshots, ...). Also, Android's ION | |
729 | * framework already supported this and for DMA buffer file descriptors to | |
730 | * replace ION buffers mmap support was needed. | |
731 | * | |
732 | * There is no special interfaces, userspace simply calls mmap on the dma-buf | |
733 | * fd. But like for CPU access there's a need to braket the actual access, | |
734 | * which is handled by the ioctl (DMA_BUF_IOCTL_SYNC). Note that | |
735 | * DMA_BUF_IOCTL_SYNC can fail with -EAGAIN or -EINTR, in which case it must | |
736 | * be restarted. | |
737 | * | |
738 | * Some systems might need some sort of cache coherency management e.g. when | |
739 | * CPU and GPU domains are being accessed through dma-buf at the same time. | |
740 | * To circumvent this problem there are begin/end coherency markers, that | |
741 | * forward directly to existing dma-buf device drivers vfunc hooks. Userspace | |
742 | * can make use of those markers through the DMA_BUF_IOCTL_SYNC ioctl. The | |
743 | * sequence would be used like following: | |
744 | * | |
745 | * - mmap dma-buf fd | |
746 | * - for each drawing/upload cycle in CPU 1. SYNC_START ioctl, 2. read/write | |
747 | * to mmap area 3. SYNC_END ioctl. This can be repeated as often as you | |
748 | * want (with the new data being consumed by say the GPU or the scanout | |
749 | * device) | |
750 | * - munmap once you don't need the buffer any more | |
751 | * | |
752 | * For correctness and optimal performance, it is always required to use | |
753 | * SYNC_START and SYNC_END before and after, respectively, when accessing the | |
754 | * mapped address. Userspace cannot rely on coherent access, even when there | |
755 | * are systems where it just works without calling these ioctls. | |
756 | * | |
757 | * - And as a CPU fallback in userspace processing pipelines. | |
758 | * | |
759 | * Similar to the motivation for kernel cpu access it is again important that | |
760 | * the userspace code of a given importing subsystem can use the same | |
761 | * interfaces with a imported dma-buf buffer object as with a native buffer | |
762 | * object. This is especially important for drm where the userspace part of | |
763 | * contemporary OpenGL, X, and other drivers is huge, and reworking them to | |
764 | * use a different way to mmap a buffer rather invasive. | |
765 | * | |
766 | * The assumption in the current dma-buf interfaces is that redirecting the | |
767 | * initial mmap is all that's needed. A survey of some of the existing | |
768 | * subsystems shows that no driver seems to do any nefarious thing like | |
769 | * syncing up with outstanding asynchronous processing on the device or | |
770 | * allocating special resources at fault time. So hopefully this is good | |
771 | * enough, since adding interfaces to intercept pagefaults and allow pte | |
772 | * shootdowns would increase the complexity quite a bit. | |
773 | * | |
774 | * Interface:: | |
775 | * int dma_buf_mmap(struct dma_buf \*, struct vm_area_struct \*, | |
776 | * unsigned long); | |
777 | * | |
778 | * If the importing subsystem simply provides a special-purpose mmap call to | |
779 | * set up a mapping in userspace, calling do_mmap with dma_buf->file will | |
780 | * equally achieve that for a dma-buf object. | |
781 | */ | |
782 | ||
ae4e46b1 CW |
783 | static int __dma_buf_begin_cpu_access(struct dma_buf *dmabuf, |
784 | enum dma_data_direction direction) | |
785 | { | |
786 | bool write = (direction == DMA_BIDIRECTIONAL || | |
787 | direction == DMA_TO_DEVICE); | |
788 | struct reservation_object *resv = dmabuf->resv; | |
789 | long ret; | |
790 | ||
791 | /* Wait on any implicit rendering fences */ | |
792 | ret = reservation_object_wait_timeout_rcu(resv, write, true, | |
793 | MAX_SCHEDULE_TIMEOUT); | |
794 | if (ret < 0) | |
795 | return ret; | |
796 | ||
797 | return 0; | |
798 | } | |
fc13020e DV |
799 | |
800 | /** | |
801 | * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the | |
802 | * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific | |
803 | * preparations. Coherency is only guaranteed in the specified range for the | |
804 | * specified access direction. | |
efb4df82 | 805 | * @dmabuf: [in] buffer to prepare cpu access for. |
fc13020e DV |
806 | * @direction: [in] length of range for cpu access. |
807 | * | |
0959a168 DV |
808 | * After the cpu access is complete the caller should call |
809 | * dma_buf_end_cpu_access(). Only when cpu access is braketed by both calls is | |
810 | * it guaranteed to be coherent with other DMA access. | |
811 | * | |
fc13020e DV |
812 | * Can return negative error values, returns 0 on success. |
813 | */ | |
831e9da7 | 814 | int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, |
fc13020e DV |
815 | enum dma_data_direction direction) |
816 | { | |
817 | int ret = 0; | |
818 | ||
819 | if (WARN_ON(!dmabuf)) | |
820 | return -EINVAL; | |
821 | ||
822 | if (dmabuf->ops->begin_cpu_access) | |
831e9da7 | 823 | ret = dmabuf->ops->begin_cpu_access(dmabuf, direction); |
fc13020e | 824 | |
ae4e46b1 CW |
825 | /* Ensure that all fences are waited upon - but we first allow |
826 | * the native handler the chance to do so more efficiently if it | |
827 | * chooses. A double invocation here will be reasonably cheap no-op. | |
828 | */ | |
829 | if (ret == 0) | |
830 | ret = __dma_buf_begin_cpu_access(dmabuf, direction); | |
831 | ||
fc13020e DV |
832 | return ret; |
833 | } | |
834 | EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access); | |
835 | ||
836 | /** | |
837 | * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the | |
838 | * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific | |
839 | * actions. Coherency is only guaranteed in the specified range for the | |
840 | * specified access direction. | |
efb4df82 | 841 | * @dmabuf: [in] buffer to complete cpu access for. |
fc13020e DV |
842 | * @direction: [in] length of range for cpu access. |
843 | * | |
0959a168 DV |
844 | * This terminates CPU access started with dma_buf_begin_cpu_access(). |
845 | * | |
87e332d5 | 846 | * Can return negative error values, returns 0 on success. |
fc13020e | 847 | */ |
18b862dc CW |
848 | int dma_buf_end_cpu_access(struct dma_buf *dmabuf, |
849 | enum dma_data_direction direction) | |
fc13020e | 850 | { |
18b862dc CW |
851 | int ret = 0; |
852 | ||
fc13020e DV |
853 | WARN_ON(!dmabuf); |
854 | ||
855 | if (dmabuf->ops->end_cpu_access) | |
18b862dc CW |
856 | ret = dmabuf->ops->end_cpu_access(dmabuf, direction); |
857 | ||
858 | return ret; | |
fc13020e DV |
859 | } |
860 | EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access); | |
861 | ||
862 | /** | |
863 | * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address | |
864 | * space. The same restrictions as for kmap_atomic and friends apply. | |
efb4df82 | 865 | * @dmabuf: [in] buffer to map page from. |
fc13020e DV |
866 | * @page_num: [in] page in PAGE_SIZE units to map. |
867 | * | |
868 | * This call must always succeed, any necessary preparations that might fail | |
869 | * need to be done in begin_cpu_access. | |
870 | */ | |
871 | void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num) | |
872 | { | |
873 | WARN_ON(!dmabuf); | |
874 | ||
875 | return dmabuf->ops->kmap_atomic(dmabuf, page_num); | |
876 | } | |
877 | EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic); | |
878 | ||
879 | /** | |
880 | * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic. | |
efb4df82 | 881 | * @dmabuf: [in] buffer to unmap page from. |
fc13020e DV |
882 | * @page_num: [in] page in PAGE_SIZE units to unmap. |
883 | * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap_atomic. | |
884 | * | |
885 | * This call must always succeed. | |
886 | */ | |
887 | void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, unsigned long page_num, | |
888 | void *vaddr) | |
889 | { | |
890 | WARN_ON(!dmabuf); | |
891 | ||
892 | if (dmabuf->ops->kunmap_atomic) | |
893 | dmabuf->ops->kunmap_atomic(dmabuf, page_num, vaddr); | |
894 | } | |
895 | EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic); | |
896 | ||
897 | /** | |
898 | * dma_buf_kmap - Map a page of the buffer object into kernel address space. The | |
899 | * same restrictions as for kmap and friends apply. | |
efb4df82 | 900 | * @dmabuf: [in] buffer to map page from. |
fc13020e DV |
901 | * @page_num: [in] page in PAGE_SIZE units to map. |
902 | * | |
903 | * This call must always succeed, any necessary preparations that might fail | |
904 | * need to be done in begin_cpu_access. | |
905 | */ | |
906 | void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num) | |
907 | { | |
908 | WARN_ON(!dmabuf); | |
909 | ||
910 | return dmabuf->ops->kmap(dmabuf, page_num); | |
911 | } | |
912 | EXPORT_SYMBOL_GPL(dma_buf_kmap); | |
913 | ||
914 | /** | |
915 | * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap. | |
efb4df82 | 916 | * @dmabuf: [in] buffer to unmap page from. |
fc13020e DV |
917 | * @page_num: [in] page in PAGE_SIZE units to unmap. |
918 | * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap. | |
919 | * | |
920 | * This call must always succeed. | |
921 | */ | |
922 | void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num, | |
923 | void *vaddr) | |
924 | { | |
925 | WARN_ON(!dmabuf); | |
926 | ||
927 | if (dmabuf->ops->kunmap) | |
928 | dmabuf->ops->kunmap(dmabuf, page_num, vaddr); | |
929 | } | |
930 | EXPORT_SYMBOL_GPL(dma_buf_kunmap); | |
4c78513e DV |
931 | |
932 | ||
933 | /** | |
934 | * dma_buf_mmap - Setup up a userspace mmap with the given vma | |
12c4727e | 935 | * @dmabuf: [in] buffer that should back the vma |
4c78513e DV |
936 | * @vma: [in] vma for the mmap |
937 | * @pgoff: [in] offset in pages where this mmap should start within the | |
5136629d | 938 | * dma-buf buffer. |
4c78513e DV |
939 | * |
940 | * This function adjusts the passed in vma so that it points at the file of the | |
ecf1dbac | 941 | * dma_buf operation. It also adjusts the starting pgoff and does bounds |
4c78513e DV |
942 | * checking on the size of the vma. Then it calls the exporters mmap function to |
943 | * set up the mapping. | |
944 | * | |
945 | * Can return negative error values, returns 0 on success. | |
946 | */ | |
947 | int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, | |
948 | unsigned long pgoff) | |
949 | { | |
495c10cc JS |
950 | struct file *oldfile; |
951 | int ret; | |
952 | ||
4c78513e DV |
953 | if (WARN_ON(!dmabuf || !vma)) |
954 | return -EINVAL; | |
955 | ||
956 | /* check for offset overflow */ | |
b02da6f8 | 957 | if (pgoff + vma_pages(vma) < pgoff) |
4c78513e DV |
958 | return -EOVERFLOW; |
959 | ||
960 | /* check for overflowing the buffer's size */ | |
b02da6f8 | 961 | if (pgoff + vma_pages(vma) > |
4c78513e DV |
962 | dmabuf->size >> PAGE_SHIFT) |
963 | return -EINVAL; | |
964 | ||
965 | /* readjust the vma */ | |
495c10cc JS |
966 | get_file(dmabuf->file); |
967 | oldfile = vma->vm_file; | |
968 | vma->vm_file = dmabuf->file; | |
4c78513e DV |
969 | vma->vm_pgoff = pgoff; |
970 | ||
495c10cc JS |
971 | ret = dmabuf->ops->mmap(dmabuf, vma); |
972 | if (ret) { | |
973 | /* restore old parameters on failure */ | |
974 | vma->vm_file = oldfile; | |
975 | fput(dmabuf->file); | |
976 | } else { | |
977 | if (oldfile) | |
978 | fput(oldfile); | |
979 | } | |
980 | return ret; | |
981 | ||
4c78513e DV |
982 | } |
983 | EXPORT_SYMBOL_GPL(dma_buf_mmap); | |
98f86c9e DA |
984 | |
985 | /** | |
12c4727e SS |
986 | * dma_buf_vmap - Create virtual mapping for the buffer object into kernel |
987 | * address space. Same restrictions as for vmap and friends apply. | |
988 | * @dmabuf: [in] buffer to vmap | |
98f86c9e DA |
989 | * |
990 | * This call may fail due to lack of virtual mapping address space. | |
991 | * These calls are optional in drivers. The intended use for them | |
992 | * is for mapping objects linear in kernel space for high use objects. | |
993 | * Please attempt to use kmap/kunmap before thinking about these interfaces. | |
fee0c54e CC |
994 | * |
995 | * Returns NULL on error. | |
98f86c9e DA |
996 | */ |
997 | void *dma_buf_vmap(struct dma_buf *dmabuf) | |
998 | { | |
f00b4dad DV |
999 | void *ptr; |
1000 | ||
98f86c9e DA |
1001 | if (WARN_ON(!dmabuf)) |
1002 | return NULL; | |
1003 | ||
f00b4dad DV |
1004 | if (!dmabuf->ops->vmap) |
1005 | return NULL; | |
1006 | ||
1007 | mutex_lock(&dmabuf->lock); | |
1008 | if (dmabuf->vmapping_counter) { | |
1009 | dmabuf->vmapping_counter++; | |
1010 | BUG_ON(!dmabuf->vmap_ptr); | |
1011 | ptr = dmabuf->vmap_ptr; | |
1012 | goto out_unlock; | |
1013 | } | |
1014 | ||
1015 | BUG_ON(dmabuf->vmap_ptr); | |
1016 | ||
1017 | ptr = dmabuf->ops->vmap(dmabuf); | |
fee0c54e CC |
1018 | if (WARN_ON_ONCE(IS_ERR(ptr))) |
1019 | ptr = NULL; | |
1020 | if (!ptr) | |
f00b4dad DV |
1021 | goto out_unlock; |
1022 | ||
1023 | dmabuf->vmap_ptr = ptr; | |
1024 | dmabuf->vmapping_counter = 1; | |
1025 | ||
1026 | out_unlock: | |
1027 | mutex_unlock(&dmabuf->lock); | |
1028 | return ptr; | |
98f86c9e DA |
1029 | } |
1030 | EXPORT_SYMBOL_GPL(dma_buf_vmap); | |
1031 | ||
1032 | /** | |
1033 | * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap. | |
12c4727e | 1034 | * @dmabuf: [in] buffer to vunmap |
6e7b4a59 | 1035 | * @vaddr: [in] vmap to vunmap |
98f86c9e DA |
1036 | */ |
1037 | void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr) | |
1038 | { | |
1039 | if (WARN_ON(!dmabuf)) | |
1040 | return; | |
1041 | ||
f00b4dad DV |
1042 | BUG_ON(!dmabuf->vmap_ptr); |
1043 | BUG_ON(dmabuf->vmapping_counter == 0); | |
1044 | BUG_ON(dmabuf->vmap_ptr != vaddr); | |
1045 | ||
1046 | mutex_lock(&dmabuf->lock); | |
1047 | if (--dmabuf->vmapping_counter == 0) { | |
1048 | if (dmabuf->ops->vunmap) | |
1049 | dmabuf->ops->vunmap(dmabuf, vaddr); | |
1050 | dmabuf->vmap_ptr = NULL; | |
1051 | } | |
1052 | mutex_unlock(&dmabuf->lock); | |
98f86c9e DA |
1053 | } |
1054 | EXPORT_SYMBOL_GPL(dma_buf_vunmap); | |
b89e3563 SS |
1055 | |
1056 | #ifdef CONFIG_DEBUG_FS | |
eb0b947e | 1057 | static int dma_buf_debug_show(struct seq_file *s, void *unused) |
b89e3563 SS |
1058 | { |
1059 | int ret; | |
1060 | struct dma_buf *buf_obj; | |
1061 | struct dma_buf_attachment *attach_obj; | |
1062 | int count = 0, attach_count; | |
1063 | size_t size = 0; | |
1064 | ||
1065 | ret = mutex_lock_interruptible(&db_list.lock); | |
1066 | ||
1067 | if (ret) | |
1068 | return ret; | |
1069 | ||
c0b00a52 SS |
1070 | seq_puts(s, "\nDma-buf Objects:\n"); |
1071 | seq_puts(s, "size\tflags\tmode\tcount\texp_name\n"); | |
b89e3563 SS |
1072 | |
1073 | list_for_each_entry(buf_obj, &db_list.head, list_node) { | |
1074 | ret = mutex_lock_interruptible(&buf_obj->lock); | |
1075 | ||
1076 | if (ret) { | |
c0b00a52 SS |
1077 | seq_puts(s, |
1078 | "\tERROR locking buffer object: skipping\n"); | |
b89e3563 SS |
1079 | continue; |
1080 | } | |
1081 | ||
c0b00a52 SS |
1082 | seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\n", |
1083 | buf_obj->size, | |
b89e3563 | 1084 | buf_obj->file->f_flags, buf_obj->file->f_mode, |
a1f6dbac | 1085 | file_count(buf_obj->file), |
c0b00a52 | 1086 | buf_obj->exp_name); |
b89e3563 | 1087 | |
c0b00a52 | 1088 | seq_puts(s, "\tAttached Devices:\n"); |
b89e3563 SS |
1089 | attach_count = 0; |
1090 | ||
1091 | list_for_each_entry(attach_obj, &buf_obj->attachments, node) { | |
c0b00a52 | 1092 | seq_puts(s, "\t"); |
b89e3563 | 1093 | |
c0b00a52 | 1094 | seq_printf(s, "%s\n", dev_name(attach_obj->dev)); |
b89e3563 SS |
1095 | attach_count++; |
1096 | } | |
1097 | ||
c0b00a52 | 1098 | seq_printf(s, "Total %d devices attached\n\n", |
b89e3563 SS |
1099 | attach_count); |
1100 | ||
1101 | count++; | |
1102 | size += buf_obj->size; | |
1103 | mutex_unlock(&buf_obj->lock); | |
1104 | } | |
1105 | ||
1106 | seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size); | |
1107 | ||
1108 | mutex_unlock(&db_list.lock); | |
1109 | return 0; | |
1110 | } | |
1111 | ||
b89e3563 SS |
1112 | static int dma_buf_debug_open(struct inode *inode, struct file *file) |
1113 | { | |
eb0b947e | 1114 | return single_open(file, dma_buf_debug_show, NULL); |
b89e3563 SS |
1115 | } |
1116 | ||
1117 | static const struct file_operations dma_buf_debug_fops = { | |
1118 | .open = dma_buf_debug_open, | |
1119 | .read = seq_read, | |
1120 | .llseek = seq_lseek, | |
1121 | .release = single_release, | |
1122 | }; | |
1123 | ||
1124 | static struct dentry *dma_buf_debugfs_dir; | |
1125 | ||
1126 | static int dma_buf_init_debugfs(void) | |
1127 | { | |
bd3e2208 | 1128 | struct dentry *d; |
b89e3563 | 1129 | int err = 0; |
5136629d | 1130 | |
bd3e2208 MK |
1131 | d = debugfs_create_dir("dma_buf", NULL); |
1132 | if (IS_ERR(d)) | |
1133 | return PTR_ERR(d); | |
5136629d | 1134 | |
bd3e2208 | 1135 | dma_buf_debugfs_dir = d; |
b89e3563 | 1136 | |
bd3e2208 MK |
1137 | d = debugfs_create_file("bufinfo", S_IRUGO, dma_buf_debugfs_dir, |
1138 | NULL, &dma_buf_debug_fops); | |
1139 | if (IS_ERR(d)) { | |
b89e3563 | 1140 | pr_debug("dma_buf: debugfs: failed to create node bufinfo\n"); |
b7479990 MK |
1141 | debugfs_remove_recursive(dma_buf_debugfs_dir); |
1142 | dma_buf_debugfs_dir = NULL; | |
bd3e2208 | 1143 | err = PTR_ERR(d); |
b7479990 | 1144 | } |
b89e3563 SS |
1145 | |
1146 | return err; | |
1147 | } | |
1148 | ||
1149 | static void dma_buf_uninit_debugfs(void) | |
1150 | { | |
1151 | if (dma_buf_debugfs_dir) | |
1152 | debugfs_remove_recursive(dma_buf_debugfs_dir); | |
1153 | } | |
b89e3563 SS |
1154 | #else |
1155 | static inline int dma_buf_init_debugfs(void) | |
1156 | { | |
1157 | return 0; | |
1158 | } | |
1159 | static inline void dma_buf_uninit_debugfs(void) | |
1160 | { | |
1161 | } | |
1162 | #endif | |
1163 | ||
1164 | static int __init dma_buf_init(void) | |
1165 | { | |
1166 | mutex_init(&db_list.lock); | |
1167 | INIT_LIST_HEAD(&db_list.head); | |
1168 | dma_buf_init_debugfs(); | |
1169 | return 0; | |
1170 | } | |
1171 | subsys_initcall(dma_buf_init); | |
1172 | ||
1173 | static void __exit dma_buf_deinit(void) | |
1174 | { | |
1175 | dma_buf_uninit_debugfs(); | |
1176 | } | |
1177 | __exitcall(dma_buf_deinit); |