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caab277b | 1 | // SPDX-License-Identifier: GPL-2.0-only |
d15bd7ee SS |
2 | /* |
3 | * Framework for buffer objects that can be shared across devices/subsystems. | |
4 | * | |
5 | * Copyright(C) 2011 Linaro Limited. All rights reserved. | |
6 | * Author: Sumit Semwal <sumit.semwal@ti.com> | |
7 | * | |
8 | * Many thanks to linaro-mm-sig list, and specially | |
9 | * Arnd Bergmann <arnd@arndb.de>, Rob Clark <rob@ti.com> and | |
10 | * Daniel Vetter <daniel@ffwll.ch> for their support in creation and | |
11 | * refining of this idea. | |
d15bd7ee SS |
12 | */ |
13 | ||
14 | #include <linux/fs.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/dma-buf.h> | |
f54d1867 | 17 | #include <linux/dma-fence.h> |
d15bd7ee SS |
18 | #include <linux/anon_inodes.h> |
19 | #include <linux/export.h> | |
b89e3563 | 20 | #include <linux/debugfs.h> |
9abdffe2 | 21 | #include <linux/module.h> |
b89e3563 | 22 | #include <linux/seq_file.h> |
9b495a58 | 23 | #include <linux/poll.h> |
52791eee | 24 | #include <linux/dma-resv.h> |
b02da6f8 | 25 | #include <linux/mm.h> |
ed63bb1d | 26 | #include <linux/mount.h> |
933a90bf | 27 | #include <linux/pseudo_fs.h> |
d15bd7ee | 28 | |
c11e391d | 29 | #include <uapi/linux/dma-buf.h> |
ed63bb1d | 30 | #include <uapi/linux/magic.h> |
c11e391d | 31 | |
d15bd7ee SS |
32 | static inline int is_dma_buf_file(struct file *); |
33 | ||
b89e3563 SS |
34 | struct dma_buf_list { |
35 | struct list_head head; | |
36 | struct mutex lock; | |
37 | }; | |
38 | ||
39 | static struct dma_buf_list db_list; | |
40 | ||
bb2bb903 GH |
41 | static char *dmabuffs_dname(struct dentry *dentry, char *buffer, int buflen) |
42 | { | |
43 | struct dma_buf *dmabuf; | |
44 | char name[DMA_BUF_NAME_LEN]; | |
45 | size_t ret = 0; | |
46 | ||
47 | dmabuf = dentry->d_fsdata; | |
48 | mutex_lock(&dmabuf->lock); | |
49 | if (dmabuf->name) | |
50 | ret = strlcpy(name, dmabuf->name, DMA_BUF_NAME_LEN); | |
51 | mutex_unlock(&dmabuf->lock); | |
52 | ||
53 | return dynamic_dname(dentry, buffer, buflen, "/%s:%s", | |
54 | dentry->d_name.name, ret > 0 ? name : ""); | |
55 | } | |
56 | ||
ed63bb1d | 57 | static const struct dentry_operations dma_buf_dentry_ops = { |
bb2bb903 | 58 | .d_dname = dmabuffs_dname, |
ed63bb1d GH |
59 | }; |
60 | ||
61 | static struct vfsmount *dma_buf_mnt; | |
62 | ||
933a90bf | 63 | static int dma_buf_fs_init_context(struct fs_context *fc) |
ed63bb1d | 64 | { |
933a90bf LT |
65 | struct pseudo_fs_context *ctx; |
66 | ||
67 | ctx = init_pseudo(fc, DMA_BUF_MAGIC); | |
68 | if (!ctx) | |
69 | return -ENOMEM; | |
70 | ctx->dops = &dma_buf_dentry_ops; | |
71 | return 0; | |
ed63bb1d GH |
72 | } |
73 | ||
74 | static struct file_system_type dma_buf_fs_type = { | |
75 | .name = "dmabuf", | |
933a90bf | 76 | .init_fs_context = dma_buf_fs_init_context, |
ed63bb1d GH |
77 | .kill_sb = kill_anon_super, |
78 | }; | |
79 | ||
d15bd7ee SS |
80 | static int dma_buf_release(struct inode *inode, struct file *file) |
81 | { | |
82 | struct dma_buf *dmabuf; | |
83 | ||
84 | if (!is_dma_buf_file(file)) | |
85 | return -EINVAL; | |
86 | ||
87 | dmabuf = file->private_data; | |
88 | ||
f00b4dad DV |
89 | BUG_ON(dmabuf->vmapping_counter); |
90 | ||
9b495a58 ML |
91 | /* |
92 | * Any fences that a dma-buf poll can wait on should be signaled | |
93 | * before releasing dma-buf. This is the responsibility of each | |
94 | * driver that uses the reservation objects. | |
95 | * | |
96 | * If you hit this BUG() it means someone dropped their ref to the | |
97 | * dma-buf while still having pending operation to the buffer. | |
98 | */ | |
99 | BUG_ON(dmabuf->cb_shared.active || dmabuf->cb_excl.active); | |
100 | ||
d15bd7ee | 101 | dmabuf->ops->release(dmabuf); |
b89e3563 SS |
102 | |
103 | mutex_lock(&db_list.lock); | |
104 | list_del(&dmabuf->list_node); | |
105 | mutex_unlock(&db_list.lock); | |
106 | ||
52791eee CK |
107 | if (dmabuf->resv == (struct dma_resv *)&dmabuf[1]) |
108 | dma_resv_fini(dmabuf->resv); | |
3aac4502 | 109 | |
9abdffe2 | 110 | module_put(dmabuf->owner); |
d15bd7ee SS |
111 | kfree(dmabuf); |
112 | return 0; | |
113 | } | |
114 | ||
4c78513e DV |
115 | static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) |
116 | { | |
117 | struct dma_buf *dmabuf; | |
118 | ||
119 | if (!is_dma_buf_file(file)) | |
120 | return -EINVAL; | |
121 | ||
122 | dmabuf = file->private_data; | |
123 | ||
e3a9d6c5 AD |
124 | /* check if buffer supports mmap */ |
125 | if (!dmabuf->ops->mmap) | |
126 | return -EINVAL; | |
127 | ||
4c78513e | 128 | /* check for overflowing the buffer's size */ |
b02da6f8 | 129 | if (vma->vm_pgoff + vma_pages(vma) > |
4c78513e DV |
130 | dmabuf->size >> PAGE_SHIFT) |
131 | return -EINVAL; | |
132 | ||
133 | return dmabuf->ops->mmap(dmabuf, vma); | |
134 | } | |
135 | ||
19e8697b CJHR |
136 | static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence) |
137 | { | |
138 | struct dma_buf *dmabuf; | |
139 | loff_t base; | |
140 | ||
141 | if (!is_dma_buf_file(file)) | |
142 | return -EBADF; | |
143 | ||
144 | dmabuf = file->private_data; | |
145 | ||
146 | /* only support discovering the end of the buffer, | |
147 | but also allow SEEK_SET to maintain the idiomatic | |
148 | SEEK_END(0), SEEK_CUR(0) pattern */ | |
149 | if (whence == SEEK_END) | |
150 | base = dmabuf->size; | |
151 | else if (whence == SEEK_SET) | |
152 | base = 0; | |
153 | else | |
154 | return -EINVAL; | |
155 | ||
156 | if (offset != 0) | |
157 | return -EINVAL; | |
158 | ||
159 | return base + offset; | |
160 | } | |
161 | ||
e7e21c72 DV |
162 | /** |
163 | * DOC: fence polling | |
164 | * | |
165 | * To support cross-device and cross-driver synchronization of buffer access | |
f641d3b5 | 166 | * implicit fences (represented internally in the kernel with &struct fence) can |
e7e21c72 | 167 | * be attached to a &dma_buf. The glue for that and a few related things are |
52791eee | 168 | * provided in the &dma_resv structure. |
e7e21c72 DV |
169 | * |
170 | * Userspace can query the state of these implicitly tracked fences using poll() | |
171 | * and related system calls: | |
172 | * | |
a9a08845 | 173 | * - Checking for EPOLLIN, i.e. read access, can be use to query the state of the |
e7e21c72 DV |
174 | * most recent write or exclusive fence. |
175 | * | |
a9a08845 | 176 | * - Checking for EPOLLOUT, i.e. write access, can be used to query the state of |
e7e21c72 DV |
177 | * all attached fences, shared and exclusive ones. |
178 | * | |
179 | * Note that this only signals the completion of the respective fences, i.e. the | |
180 | * DMA transfers are complete. Cache flushing and any other necessary | |
181 | * preparations before CPU access can begin still need to happen. | |
182 | */ | |
183 | ||
f54d1867 | 184 | static void dma_buf_poll_cb(struct dma_fence *fence, struct dma_fence_cb *cb) |
9b495a58 ML |
185 | { |
186 | struct dma_buf_poll_cb_t *dcb = (struct dma_buf_poll_cb_t *)cb; | |
187 | unsigned long flags; | |
188 | ||
189 | spin_lock_irqsave(&dcb->poll->lock, flags); | |
190 | wake_up_locked_poll(dcb->poll, dcb->active); | |
191 | dcb->active = 0; | |
192 | spin_unlock_irqrestore(&dcb->poll->lock, flags); | |
193 | } | |
194 | ||
afc9a42b | 195 | static __poll_t dma_buf_poll(struct file *file, poll_table *poll) |
9b495a58 ML |
196 | { |
197 | struct dma_buf *dmabuf; | |
52791eee CK |
198 | struct dma_resv *resv; |
199 | struct dma_resv_list *fobj; | |
f54d1867 | 200 | struct dma_fence *fence_excl; |
01699437 | 201 | __poll_t events; |
67c97fb7 | 202 | unsigned shared_count; |
9b495a58 ML |
203 | |
204 | dmabuf = file->private_data; | |
205 | if (!dmabuf || !dmabuf->resv) | |
a9a08845 | 206 | return EPOLLERR; |
9b495a58 ML |
207 | |
208 | resv = dmabuf->resv; | |
209 | ||
210 | poll_wait(file, &dmabuf->poll, poll); | |
211 | ||
a9a08845 | 212 | events = poll_requested_events(poll) & (EPOLLIN | EPOLLOUT); |
9b495a58 ML |
213 | if (!events) |
214 | return 0; | |
215 | ||
3c3b177a | 216 | rcu_read_lock(); |
52791eee | 217 | dma_resv_fences(resv, &fence_excl, &fobj, &shared_count); |
a9a08845 | 218 | if (fence_excl && (!(events & EPOLLOUT) || shared_count == 0)) { |
9b495a58 | 219 | struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_excl; |
a9a08845 | 220 | __poll_t pevents = EPOLLIN; |
9b495a58 | 221 | |
04a5faa8 | 222 | if (shared_count == 0) |
a9a08845 | 223 | pevents |= EPOLLOUT; |
9b495a58 ML |
224 | |
225 | spin_lock_irq(&dmabuf->poll.lock); | |
226 | if (dcb->active) { | |
227 | dcb->active |= pevents; | |
228 | events &= ~pevents; | |
229 | } else | |
230 | dcb->active = pevents; | |
231 | spin_unlock_irq(&dmabuf->poll.lock); | |
232 | ||
233 | if (events & pevents) { | |
f54d1867 | 234 | if (!dma_fence_get_rcu(fence_excl)) { |
3c3b177a ML |
235 | /* force a recheck */ |
236 | events &= ~pevents; | |
237 | dma_buf_poll_cb(NULL, &dcb->cb); | |
f54d1867 CW |
238 | } else if (!dma_fence_add_callback(fence_excl, &dcb->cb, |
239 | dma_buf_poll_cb)) { | |
9b495a58 | 240 | events &= ~pevents; |
f54d1867 | 241 | dma_fence_put(fence_excl); |
04a5faa8 | 242 | } else { |
9b495a58 ML |
243 | /* |
244 | * No callback queued, wake up any additional | |
245 | * waiters. | |
246 | */ | |
f54d1867 | 247 | dma_fence_put(fence_excl); |
9b495a58 | 248 | dma_buf_poll_cb(NULL, &dcb->cb); |
04a5faa8 | 249 | } |
9b495a58 ML |
250 | } |
251 | } | |
252 | ||
a9a08845 | 253 | if ((events & EPOLLOUT) && shared_count > 0) { |
9b495a58 ML |
254 | struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_shared; |
255 | int i; | |
256 | ||
257 | /* Only queue a new callback if no event has fired yet */ | |
258 | spin_lock_irq(&dmabuf->poll.lock); | |
259 | if (dcb->active) | |
a9a08845 | 260 | events &= ~EPOLLOUT; |
9b495a58 | 261 | else |
a9a08845 | 262 | dcb->active = EPOLLOUT; |
9b495a58 ML |
263 | spin_unlock_irq(&dmabuf->poll.lock); |
264 | ||
a9a08845 | 265 | if (!(events & EPOLLOUT)) |
9b495a58 ML |
266 | goto out; |
267 | ||
04a5faa8 | 268 | for (i = 0; i < shared_count; ++i) { |
f54d1867 | 269 | struct dma_fence *fence = rcu_dereference(fobj->shared[i]); |
04a5faa8 | 270 | |
f54d1867 | 271 | if (!dma_fence_get_rcu(fence)) { |
3c3b177a ML |
272 | /* |
273 | * fence refcount dropped to zero, this means | |
274 | * that fobj has been freed | |
275 | * | |
276 | * call dma_buf_poll_cb and force a recheck! | |
277 | */ | |
a9a08845 | 278 | events &= ~EPOLLOUT; |
3c3b177a ML |
279 | dma_buf_poll_cb(NULL, &dcb->cb); |
280 | break; | |
281 | } | |
f54d1867 CW |
282 | if (!dma_fence_add_callback(fence, &dcb->cb, |
283 | dma_buf_poll_cb)) { | |
284 | dma_fence_put(fence); | |
a9a08845 | 285 | events &= ~EPOLLOUT; |
9b495a58 ML |
286 | break; |
287 | } | |
f54d1867 | 288 | dma_fence_put(fence); |
04a5faa8 | 289 | } |
9b495a58 ML |
290 | |
291 | /* No callback queued, wake up any additional waiters. */ | |
04a5faa8 | 292 | if (i == shared_count) |
9b495a58 ML |
293 | dma_buf_poll_cb(NULL, &dcb->cb); |
294 | } | |
295 | ||
296 | out: | |
3c3b177a | 297 | rcu_read_unlock(); |
9b495a58 ML |
298 | return events; |
299 | } | |
300 | ||
bb2bb903 GH |
301 | /** |
302 | * dma_buf_set_name - Set a name to a specific dma_buf to track the usage. | |
303 | * The name of the dma-buf buffer can only be set when the dma-buf is not | |
304 | * attached to any devices. It could theoritically support changing the | |
305 | * name of the dma-buf if the same piece of memory is used for multiple | |
306 | * purpose between different devices. | |
307 | * | |
308 | * @dmabuf [in] dmabuf buffer that will be renamed. | |
309 | * @buf: [in] A piece of userspace memory that contains the name of | |
310 | * the dma-buf. | |
311 | * | |
312 | * Returns 0 on success. If the dma-buf buffer is already attached to | |
313 | * devices, return -EBUSY. | |
314 | * | |
315 | */ | |
316 | static long dma_buf_set_name(struct dma_buf *dmabuf, const char __user *buf) | |
317 | { | |
318 | char *name = strndup_user(buf, DMA_BUF_NAME_LEN); | |
319 | long ret = 0; | |
320 | ||
321 | if (IS_ERR(name)) | |
322 | return PTR_ERR(name); | |
323 | ||
324 | mutex_lock(&dmabuf->lock); | |
325 | if (!list_empty(&dmabuf->attachments)) { | |
326 | ret = -EBUSY; | |
327 | kfree(name); | |
328 | goto out_unlock; | |
329 | } | |
330 | kfree(dmabuf->name); | |
331 | dmabuf->name = name; | |
332 | ||
333 | out_unlock: | |
334 | mutex_unlock(&dmabuf->lock); | |
335 | return ret; | |
336 | } | |
337 | ||
c11e391d DV |
338 | static long dma_buf_ioctl(struct file *file, |
339 | unsigned int cmd, unsigned long arg) | |
340 | { | |
341 | struct dma_buf *dmabuf; | |
342 | struct dma_buf_sync sync; | |
343 | enum dma_data_direction direction; | |
18b862dc | 344 | int ret; |
c11e391d DV |
345 | |
346 | dmabuf = file->private_data; | |
347 | ||
348 | switch (cmd) { | |
349 | case DMA_BUF_IOCTL_SYNC: | |
350 | if (copy_from_user(&sync, (void __user *) arg, sizeof(sync))) | |
351 | return -EFAULT; | |
352 | ||
353 | if (sync.flags & ~DMA_BUF_SYNC_VALID_FLAGS_MASK) | |
354 | return -EINVAL; | |
355 | ||
356 | switch (sync.flags & DMA_BUF_SYNC_RW) { | |
357 | case DMA_BUF_SYNC_READ: | |
358 | direction = DMA_FROM_DEVICE; | |
359 | break; | |
360 | case DMA_BUF_SYNC_WRITE: | |
361 | direction = DMA_TO_DEVICE; | |
362 | break; | |
363 | case DMA_BUF_SYNC_RW: | |
364 | direction = DMA_BIDIRECTIONAL; | |
365 | break; | |
366 | default: | |
367 | return -EINVAL; | |
368 | } | |
369 | ||
370 | if (sync.flags & DMA_BUF_SYNC_END) | |
18b862dc | 371 | ret = dma_buf_end_cpu_access(dmabuf, direction); |
c11e391d | 372 | else |
18b862dc | 373 | ret = dma_buf_begin_cpu_access(dmabuf, direction); |
c11e391d | 374 | |
18b862dc | 375 | return ret; |
bb2bb903 GH |
376 | |
377 | case DMA_BUF_SET_NAME: | |
378 | return dma_buf_set_name(dmabuf, (const char __user *)arg); | |
379 | ||
c11e391d DV |
380 | default: |
381 | return -ENOTTY; | |
382 | } | |
383 | } | |
384 | ||
bcc07111 GH |
385 | static void dma_buf_show_fdinfo(struct seq_file *m, struct file *file) |
386 | { | |
387 | struct dma_buf *dmabuf = file->private_data; | |
388 | ||
389 | seq_printf(m, "size:\t%zu\n", dmabuf->size); | |
390 | /* Don't count the temporary reference taken inside procfs seq_show */ | |
391 | seq_printf(m, "count:\t%ld\n", file_count(dmabuf->file) - 1); | |
392 | seq_printf(m, "exp_name:\t%s\n", dmabuf->exp_name); | |
393 | mutex_lock(&dmabuf->lock); | |
394 | if (dmabuf->name) | |
395 | seq_printf(m, "name:\t%s\n", dmabuf->name); | |
396 | mutex_unlock(&dmabuf->lock); | |
397 | } | |
398 | ||
d15bd7ee SS |
399 | static const struct file_operations dma_buf_fops = { |
400 | .release = dma_buf_release, | |
4c78513e | 401 | .mmap = dma_buf_mmap_internal, |
19e8697b | 402 | .llseek = dma_buf_llseek, |
9b495a58 | 403 | .poll = dma_buf_poll, |
c11e391d | 404 | .unlocked_ioctl = dma_buf_ioctl, |
888022c0 MS |
405 | #ifdef CONFIG_COMPAT |
406 | .compat_ioctl = dma_buf_ioctl, | |
407 | #endif | |
bcc07111 | 408 | .show_fdinfo = dma_buf_show_fdinfo, |
d15bd7ee SS |
409 | }; |
410 | ||
411 | /* | |
412 | * is_dma_buf_file - Check if struct file* is associated with dma_buf | |
413 | */ | |
414 | static inline int is_dma_buf_file(struct file *file) | |
415 | { | |
416 | return file->f_op == &dma_buf_fops; | |
417 | } | |
418 | ||
ed63bb1d GH |
419 | static struct file *dma_buf_getfile(struct dma_buf *dmabuf, int flags) |
420 | { | |
421 | struct file *file; | |
422 | struct inode *inode = alloc_anon_inode(dma_buf_mnt->mnt_sb); | |
423 | ||
424 | if (IS_ERR(inode)) | |
425 | return ERR_CAST(inode); | |
426 | ||
427 | inode->i_size = dmabuf->size; | |
428 | inode_set_bytes(inode, dmabuf->size); | |
429 | ||
430 | file = alloc_file_pseudo(inode, dma_buf_mnt, "dmabuf", | |
431 | flags, &dma_buf_fops); | |
432 | if (IS_ERR(file)) | |
433 | goto err_alloc_file; | |
434 | file->f_flags = flags & (O_ACCMODE | O_NONBLOCK); | |
435 | file->private_data = dmabuf; | |
bb2bb903 | 436 | file->f_path.dentry->d_fsdata = dmabuf; |
ed63bb1d GH |
437 | |
438 | return file; | |
439 | ||
440 | err_alloc_file: | |
441 | iput(inode); | |
442 | return file; | |
443 | } | |
444 | ||
2904a8c1 DV |
445 | /** |
446 | * DOC: dma buf device access | |
447 | * | |
448 | * For device DMA access to a shared DMA buffer the usual sequence of operations | |
449 | * is fairly simple: | |
450 | * | |
451 | * 1. The exporter defines his exporter instance using | |
452 | * DEFINE_DMA_BUF_EXPORT_INFO() and calls dma_buf_export() to wrap a private | |
453 | * buffer object into a &dma_buf. It then exports that &dma_buf to userspace | |
454 | * as a file descriptor by calling dma_buf_fd(). | |
455 | * | |
456 | * 2. Userspace passes this file-descriptors to all drivers it wants this buffer | |
457 | * to share with: First the filedescriptor is converted to a &dma_buf using | |
c138782d | 458 | * dma_buf_get(). Then the buffer is attached to the device using |
2904a8c1 DV |
459 | * dma_buf_attach(). |
460 | * | |
461 | * Up to this stage the exporter is still free to migrate or reallocate the | |
462 | * backing storage. | |
463 | * | |
c138782d | 464 | * 3. Once the buffer is attached to all devices userspace can initiate DMA |
2904a8c1 DV |
465 | * access to the shared buffer. In the kernel this is done by calling |
466 | * dma_buf_map_attachment() and dma_buf_unmap_attachment(). | |
467 | * | |
468 | * 4. Once a driver is done with a shared buffer it needs to call | |
469 | * dma_buf_detach() (after cleaning up any mappings) and then release the | |
470 | * reference acquired with dma_buf_get by calling dma_buf_put(). | |
471 | * | |
472 | * For the detailed semantics exporters are expected to implement see | |
473 | * &dma_buf_ops. | |
474 | */ | |
475 | ||
d15bd7ee | 476 | /** |
d8fbe341 | 477 | * dma_buf_export - Creates a new dma_buf, and associates an anon file |
d15bd7ee SS |
478 | * with this buffer, so it can be exported. |
479 | * Also connect the allocator specific data and ops to the buffer. | |
78df9695 | 480 | * Additionally, provide a name string for exporter; useful in debugging. |
d15bd7ee | 481 | * |
d8fbe341 | 482 | * @exp_info: [in] holds all the export related information provided |
f641d3b5 | 483 | * by the exporter. see &struct dma_buf_export_info |
d8fbe341 | 484 | * for further details. |
d15bd7ee SS |
485 | * |
486 | * Returns, on success, a newly created dma_buf object, which wraps the | |
487 | * supplied private data and operations for dma_buf_ops. On either missing | |
488 | * ops, or error in allocating struct dma_buf, will return negative error. | |
489 | * | |
2904a8c1 DV |
490 | * For most cases the easiest way to create @exp_info is through the |
491 | * %DEFINE_DMA_BUF_EXPORT_INFO macro. | |
d15bd7ee | 492 | */ |
d8fbe341 | 493 | struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) |
d15bd7ee SS |
494 | { |
495 | struct dma_buf *dmabuf; | |
52791eee | 496 | struct dma_resv *resv = exp_info->resv; |
d15bd7ee | 497 | struct file *file; |
3aac4502 | 498 | size_t alloc_size = sizeof(struct dma_buf); |
a026df4c | 499 | int ret; |
5136629d | 500 | |
d8fbe341 | 501 | if (!exp_info->resv) |
52791eee | 502 | alloc_size += sizeof(struct dma_resv); |
3aac4502 ML |
503 | else |
504 | /* prevent &dma_buf[1] == dma_buf->resv */ | |
505 | alloc_size += 1; | |
d15bd7ee | 506 | |
d8fbe341 SS |
507 | if (WARN_ON(!exp_info->priv |
508 | || !exp_info->ops | |
509 | || !exp_info->ops->map_dma_buf | |
510 | || !exp_info->ops->unmap_dma_buf | |
e3a9d6c5 | 511 | || !exp_info->ops->release)) { |
d15bd7ee SS |
512 | return ERR_PTR(-EINVAL); |
513 | } | |
514 | ||
9abdffe2 SS |
515 | if (!try_module_get(exp_info->owner)) |
516 | return ERR_PTR(-ENOENT); | |
517 | ||
3aac4502 | 518 | dmabuf = kzalloc(alloc_size, GFP_KERNEL); |
9abdffe2 | 519 | if (!dmabuf) { |
a026df4c CW |
520 | ret = -ENOMEM; |
521 | goto err_module; | |
9abdffe2 | 522 | } |
d15bd7ee | 523 | |
d8fbe341 SS |
524 | dmabuf->priv = exp_info->priv; |
525 | dmabuf->ops = exp_info->ops; | |
526 | dmabuf->size = exp_info->size; | |
527 | dmabuf->exp_name = exp_info->exp_name; | |
9abdffe2 | 528 | dmabuf->owner = exp_info->owner; |
9b495a58 ML |
529 | init_waitqueue_head(&dmabuf->poll); |
530 | dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll; | |
531 | dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0; | |
532 | ||
3aac4502 | 533 | if (!resv) { |
52791eee CK |
534 | resv = (struct dma_resv *)&dmabuf[1]; |
535 | dma_resv_init(resv); | |
3aac4502 ML |
536 | } |
537 | dmabuf->resv = resv; | |
d15bd7ee | 538 | |
ed63bb1d | 539 | file = dma_buf_getfile(dmabuf, exp_info->flags); |
9022e24e | 540 | if (IS_ERR(file)) { |
a026df4c CW |
541 | ret = PTR_ERR(file); |
542 | goto err_dmabuf; | |
9022e24e | 543 | } |
19e8697b CJHR |
544 | |
545 | file->f_mode |= FMODE_LSEEK; | |
d15bd7ee SS |
546 | dmabuf->file = file; |
547 | ||
548 | mutex_init(&dmabuf->lock); | |
549 | INIT_LIST_HEAD(&dmabuf->attachments); | |
550 | ||
b89e3563 SS |
551 | mutex_lock(&db_list.lock); |
552 | list_add(&dmabuf->list_node, &db_list.head); | |
553 | mutex_unlock(&db_list.lock); | |
554 | ||
d15bd7ee | 555 | return dmabuf; |
a026df4c CW |
556 | |
557 | err_dmabuf: | |
558 | kfree(dmabuf); | |
559 | err_module: | |
560 | module_put(exp_info->owner); | |
561 | return ERR_PTR(ret); | |
d15bd7ee | 562 | } |
d8fbe341 | 563 | EXPORT_SYMBOL_GPL(dma_buf_export); |
d15bd7ee SS |
564 | |
565 | /** | |
566 | * dma_buf_fd - returns a file descriptor for the given dma_buf | |
567 | * @dmabuf: [in] pointer to dma_buf for which fd is required. | |
55c1c4ca | 568 | * @flags: [in] flags to give to fd |
d15bd7ee SS |
569 | * |
570 | * On success, returns an associated 'fd'. Else, returns error. | |
571 | */ | |
55c1c4ca | 572 | int dma_buf_fd(struct dma_buf *dmabuf, int flags) |
d15bd7ee | 573 | { |
f5e097f0 | 574 | int fd; |
d15bd7ee SS |
575 | |
576 | if (!dmabuf || !dmabuf->file) | |
577 | return -EINVAL; | |
578 | ||
f5e097f0 BP |
579 | fd = get_unused_fd_flags(flags); |
580 | if (fd < 0) | |
581 | return fd; | |
d15bd7ee SS |
582 | |
583 | fd_install(fd, dmabuf->file); | |
584 | ||
585 | return fd; | |
586 | } | |
587 | EXPORT_SYMBOL_GPL(dma_buf_fd); | |
588 | ||
589 | /** | |
590 | * dma_buf_get - returns the dma_buf structure related to an fd | |
591 | * @fd: [in] fd associated with the dma_buf to be returned | |
592 | * | |
593 | * On success, returns the dma_buf structure associated with an fd; uses | |
594 | * file's refcounting done by fget to increase refcount. returns ERR_PTR | |
595 | * otherwise. | |
596 | */ | |
597 | struct dma_buf *dma_buf_get(int fd) | |
598 | { | |
599 | struct file *file; | |
600 | ||
601 | file = fget(fd); | |
602 | ||
603 | if (!file) | |
604 | return ERR_PTR(-EBADF); | |
605 | ||
606 | if (!is_dma_buf_file(file)) { | |
607 | fput(file); | |
608 | return ERR_PTR(-EINVAL); | |
609 | } | |
610 | ||
611 | return file->private_data; | |
612 | } | |
613 | EXPORT_SYMBOL_GPL(dma_buf_get); | |
614 | ||
615 | /** | |
616 | * dma_buf_put - decreases refcount of the buffer | |
617 | * @dmabuf: [in] buffer to reduce refcount of | |
618 | * | |
2904a8c1 DV |
619 | * Uses file's refcounting done implicitly by fput(). |
620 | * | |
621 | * If, as a result of this call, the refcount becomes 0, the 'release' file | |
e9b4d7b5 DV |
622 | * operation related to this fd is called. It calls &dma_buf_ops.release vfunc |
623 | * in turn, and frees the memory allocated for dmabuf when exported. | |
d15bd7ee SS |
624 | */ |
625 | void dma_buf_put(struct dma_buf *dmabuf) | |
626 | { | |
627 | if (WARN_ON(!dmabuf || !dmabuf->file)) | |
628 | return; | |
629 | ||
630 | fput(dmabuf->file); | |
631 | } | |
632 | EXPORT_SYMBOL_GPL(dma_buf_put); | |
633 | ||
634 | /** | |
635 | * dma_buf_attach - Add the device to dma_buf's attachments list; optionally, | |
636 | * calls attach() of dma_buf_ops to allow device-specific attach functionality | |
637 | * @dmabuf: [in] buffer to attach device to. | |
638 | * @dev: [in] device to be attached. | |
639 | * | |
2904a8c1 DV |
640 | * Returns struct dma_buf_attachment pointer for this attachment. Attachments |
641 | * must be cleaned up by calling dma_buf_detach(). | |
642 | * | |
643 | * Returns: | |
644 | * | |
645 | * A pointer to newly created &dma_buf_attachment on success, or a negative | |
646 | * error code wrapped into a pointer on failure. | |
647 | * | |
648 | * Note that this can fail if the backing storage of @dmabuf is in a place not | |
649 | * accessible to @dev, and cannot be moved to a more suitable place. This is | |
650 | * indicated with the error code -EBUSY. | |
d15bd7ee SS |
651 | */ |
652 | struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, | |
653 | struct device *dev) | |
654 | { | |
655 | struct dma_buf_attachment *attach; | |
656 | int ret; | |
657 | ||
d1aa06a1 | 658 | if (WARN_ON(!dmabuf || !dev)) |
d15bd7ee SS |
659 | return ERR_PTR(-EINVAL); |
660 | ||
db7942b6 | 661 | attach = kzalloc(sizeof(*attach), GFP_KERNEL); |
34d84ec4 | 662 | if (!attach) |
a9fbc3b7 | 663 | return ERR_PTR(-ENOMEM); |
d15bd7ee | 664 | |
d15bd7ee SS |
665 | attach->dev = dev; |
666 | attach->dmabuf = dmabuf; | |
2ed9201b LP |
667 | |
668 | mutex_lock(&dmabuf->lock); | |
669 | ||
d15bd7ee | 670 | if (dmabuf->ops->attach) { |
a19741e5 | 671 | ret = dmabuf->ops->attach(dmabuf, attach); |
d15bd7ee SS |
672 | if (ret) |
673 | goto err_attach; | |
674 | } | |
675 | list_add(&attach->node, &dmabuf->attachments); | |
676 | ||
677 | mutex_unlock(&dmabuf->lock); | |
f13e143e | 678 | |
d15bd7ee SS |
679 | return attach; |
680 | ||
d15bd7ee SS |
681 | err_attach: |
682 | kfree(attach); | |
683 | mutex_unlock(&dmabuf->lock); | |
684 | return ERR_PTR(ret); | |
685 | } | |
686 | EXPORT_SYMBOL_GPL(dma_buf_attach); | |
687 | ||
688 | /** | |
689 | * dma_buf_detach - Remove the given attachment from dmabuf's attachments list; | |
690 | * optionally calls detach() of dma_buf_ops for device-specific detach | |
691 | * @dmabuf: [in] buffer to detach from. | |
692 | * @attach: [in] attachment to be detached; is free'd after this call. | |
693 | * | |
2904a8c1 | 694 | * Clean up a device attachment obtained by calling dma_buf_attach(). |
d15bd7ee SS |
695 | */ |
696 | void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) | |
697 | { | |
d1aa06a1 | 698 | if (WARN_ON(!dmabuf || !attach)) |
d15bd7ee SS |
699 | return; |
700 | ||
f13e143e CK |
701 | if (attach->sgt) |
702 | dmabuf->ops->unmap_dma_buf(attach, attach->sgt, attach->dir); | |
703 | ||
d15bd7ee SS |
704 | mutex_lock(&dmabuf->lock); |
705 | list_del(&attach->node); | |
706 | if (dmabuf->ops->detach) | |
707 | dmabuf->ops->detach(dmabuf, attach); | |
708 | ||
709 | mutex_unlock(&dmabuf->lock); | |
710 | kfree(attach); | |
711 | } | |
712 | EXPORT_SYMBOL_GPL(dma_buf_detach); | |
713 | ||
714 | /** | |
715 | * dma_buf_map_attachment - Returns the scatterlist table of the attachment; | |
716 | * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the | |
717 | * dma_buf_ops. | |
718 | * @attach: [in] attachment whose scatterlist is to be returned | |
719 | * @direction: [in] direction of DMA transfer | |
720 | * | |
fee0c54e | 721 | * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR |
2904a8c1 DV |
722 | * on error. May return -EINTR if it is interrupted by a signal. |
723 | * | |
c138782d | 724 | * A mapping must be unmapped by using dma_buf_unmap_attachment(). Note that |
2904a8c1 DV |
725 | * the underlying backing storage is pinned for as long as a mapping exists, |
726 | * therefore users/importers should not hold onto a mapping for undue amounts of | |
727 | * time. | |
d15bd7ee SS |
728 | */ |
729 | struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, | |
730 | enum dma_data_direction direction) | |
731 | { | |
531beb06 | 732 | struct sg_table *sg_table; |
d15bd7ee SS |
733 | |
734 | might_sleep(); | |
735 | ||
d1aa06a1 | 736 | if (WARN_ON(!attach || !attach->dmabuf)) |
d15bd7ee SS |
737 | return ERR_PTR(-EINVAL); |
738 | ||
f13e143e CK |
739 | if (attach->sgt) { |
740 | /* | |
741 | * Two mappings with different directions for the same | |
742 | * attachment are not allowed. | |
743 | */ | |
744 | if (attach->dir != direction && | |
745 | attach->dir != DMA_BIDIRECTIONAL) | |
746 | return ERR_PTR(-EBUSY); | |
747 | ||
748 | return attach->sgt; | |
749 | } | |
750 | ||
d1aa06a1 | 751 | sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction); |
fee0c54e CC |
752 | if (!sg_table) |
753 | sg_table = ERR_PTR(-ENOMEM); | |
d15bd7ee | 754 | |
f13e143e CK |
755 | if (!IS_ERR(sg_table) && attach->dmabuf->ops->cache_sgt_mapping) { |
756 | attach->sgt = sg_table; | |
757 | attach->dir = direction; | |
758 | } | |
759 | ||
d15bd7ee SS |
760 | return sg_table; |
761 | } | |
762 | EXPORT_SYMBOL_GPL(dma_buf_map_attachment); | |
763 | ||
764 | /** | |
765 | * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might | |
766 | * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of | |
767 | * dma_buf_ops. | |
768 | * @attach: [in] attachment to unmap buffer from | |
769 | * @sg_table: [in] scatterlist info of the buffer to unmap | |
33ea2dcb | 770 | * @direction: [in] direction of DMA transfer |
d15bd7ee | 771 | * |
2904a8c1 | 772 | * This unmaps a DMA mapping for @attached obtained by dma_buf_map_attachment(). |
d15bd7ee SS |
773 | */ |
774 | void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, | |
33ea2dcb SS |
775 | struct sg_table *sg_table, |
776 | enum dma_data_direction direction) | |
d15bd7ee | 777 | { |
b6fa0cd6 RC |
778 | might_sleep(); |
779 | ||
d1aa06a1 | 780 | if (WARN_ON(!attach || !attach->dmabuf || !sg_table)) |
d15bd7ee SS |
781 | return; |
782 | ||
f13e143e CK |
783 | if (attach->sgt == sg_table) |
784 | return; | |
785 | ||
786 | attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, direction); | |
d15bd7ee SS |
787 | } |
788 | EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment); | |
fc13020e | 789 | |
0959a168 DV |
790 | /** |
791 | * DOC: cpu access | |
792 | * | |
793 | * There are mutliple reasons for supporting CPU access to a dma buffer object: | |
794 | * | |
795 | * - Fallback operations in the kernel, for example when a device is connected | |
796 | * over USB and the kernel needs to shuffle the data around first before | |
797 | * sending it away. Cache coherency is handled by braketing any transactions | |
798 | * with calls to dma_buf_begin_cpu_access() and dma_buf_end_cpu_access() | |
799 | * access. | |
800 | * | |
801 | * To support dma_buf objects residing in highmem cpu access is page-based | |
802 | * using an api similar to kmap. Accessing a dma_buf is done in aligned chunks | |
803 | * of PAGE_SIZE size. Before accessing a chunk it needs to be mapped, which | |
804 | * returns a pointer in kernel virtual address space. Afterwards the chunk | |
805 | * needs to be unmapped again. There is no limit on how often a given chunk | |
806 | * can be mapped and unmapped, i.e. the importer does not need to call | |
807 | * begin_cpu_access again before mapping the same chunk again. | |
808 | * | |
809 | * Interfaces:: | |
810 | * void \*dma_buf_kmap(struct dma_buf \*, unsigned long); | |
811 | * void dma_buf_kunmap(struct dma_buf \*, unsigned long, void \*); | |
812 | * | |
f664a526 CK |
813 | * Implementing the functions is optional for exporters and for importers all |
814 | * the restrictions of using kmap apply. | |
0959a168 DV |
815 | * |
816 | * dma_buf kmap calls outside of the range specified in begin_cpu_access are | |
817 | * undefined. If the range is not PAGE_SIZE aligned, kmap needs to succeed on | |
818 | * the partial chunks at the beginning and end but may return stale or bogus | |
819 | * data outside of the range (in these partial chunks). | |
820 | * | |
0959a168 DV |
821 | * For some cases the overhead of kmap can be too high, a vmap interface |
822 | * is introduced. This interface should be used very carefully, as vmalloc | |
823 | * space is a limited resources on many architectures. | |
824 | * | |
825 | * Interfaces:: | |
826 | * void \*dma_buf_vmap(struct dma_buf \*dmabuf) | |
827 | * void dma_buf_vunmap(struct dma_buf \*dmabuf, void \*vaddr) | |
828 | * | |
829 | * The vmap call can fail if there is no vmap support in the exporter, or if | |
830 | * it runs out of vmalloc space. Fallback to kmap should be implemented. Note | |
831 | * that the dma-buf layer keeps a reference count for all vmap access and | |
832 | * calls down into the exporter's vmap function only when no vmapping exists, | |
833 | * and only unmaps it once. Protection against concurrent vmap/vunmap calls is | |
834 | * provided by taking the dma_buf->lock mutex. | |
835 | * | |
836 | * - For full compatibility on the importer side with existing userspace | |
837 | * interfaces, which might already support mmap'ing buffers. This is needed in | |
838 | * many processing pipelines (e.g. feeding a software rendered image into a | |
839 | * hardware pipeline, thumbnail creation, snapshots, ...). Also, Android's ION | |
840 | * framework already supported this and for DMA buffer file descriptors to | |
841 | * replace ION buffers mmap support was needed. | |
842 | * | |
843 | * There is no special interfaces, userspace simply calls mmap on the dma-buf | |
844 | * fd. But like for CPU access there's a need to braket the actual access, | |
845 | * which is handled by the ioctl (DMA_BUF_IOCTL_SYNC). Note that | |
846 | * DMA_BUF_IOCTL_SYNC can fail with -EAGAIN or -EINTR, in which case it must | |
847 | * be restarted. | |
848 | * | |
849 | * Some systems might need some sort of cache coherency management e.g. when | |
850 | * CPU and GPU domains are being accessed through dma-buf at the same time. | |
851 | * To circumvent this problem there are begin/end coherency markers, that | |
852 | * forward directly to existing dma-buf device drivers vfunc hooks. Userspace | |
853 | * can make use of those markers through the DMA_BUF_IOCTL_SYNC ioctl. The | |
854 | * sequence would be used like following: | |
855 | * | |
856 | * - mmap dma-buf fd | |
857 | * - for each drawing/upload cycle in CPU 1. SYNC_START ioctl, 2. read/write | |
858 | * to mmap area 3. SYNC_END ioctl. This can be repeated as often as you | |
859 | * want (with the new data being consumed by say the GPU or the scanout | |
860 | * device) | |
861 | * - munmap once you don't need the buffer any more | |
862 | * | |
863 | * For correctness and optimal performance, it is always required to use | |
864 | * SYNC_START and SYNC_END before and after, respectively, when accessing the | |
865 | * mapped address. Userspace cannot rely on coherent access, even when there | |
866 | * are systems where it just works without calling these ioctls. | |
867 | * | |
868 | * - And as a CPU fallback in userspace processing pipelines. | |
869 | * | |
870 | * Similar to the motivation for kernel cpu access it is again important that | |
871 | * the userspace code of a given importing subsystem can use the same | |
872 | * interfaces with a imported dma-buf buffer object as with a native buffer | |
873 | * object. This is especially important for drm where the userspace part of | |
874 | * contemporary OpenGL, X, and other drivers is huge, and reworking them to | |
875 | * use a different way to mmap a buffer rather invasive. | |
876 | * | |
877 | * The assumption in the current dma-buf interfaces is that redirecting the | |
878 | * initial mmap is all that's needed. A survey of some of the existing | |
879 | * subsystems shows that no driver seems to do any nefarious thing like | |
880 | * syncing up with outstanding asynchronous processing on the device or | |
881 | * allocating special resources at fault time. So hopefully this is good | |
882 | * enough, since adding interfaces to intercept pagefaults and allow pte | |
883 | * shootdowns would increase the complexity quite a bit. | |
884 | * | |
885 | * Interface:: | |
886 | * int dma_buf_mmap(struct dma_buf \*, struct vm_area_struct \*, | |
887 | * unsigned long); | |
888 | * | |
889 | * If the importing subsystem simply provides a special-purpose mmap call to | |
890 | * set up a mapping in userspace, calling do_mmap with dma_buf->file will | |
891 | * equally achieve that for a dma-buf object. | |
892 | */ | |
893 | ||
ae4e46b1 CW |
894 | static int __dma_buf_begin_cpu_access(struct dma_buf *dmabuf, |
895 | enum dma_data_direction direction) | |
896 | { | |
897 | bool write = (direction == DMA_BIDIRECTIONAL || | |
898 | direction == DMA_TO_DEVICE); | |
52791eee | 899 | struct dma_resv *resv = dmabuf->resv; |
ae4e46b1 CW |
900 | long ret; |
901 | ||
902 | /* Wait on any implicit rendering fences */ | |
52791eee | 903 | ret = dma_resv_wait_timeout_rcu(resv, write, true, |
ae4e46b1 CW |
904 | MAX_SCHEDULE_TIMEOUT); |
905 | if (ret < 0) | |
906 | return ret; | |
907 | ||
908 | return 0; | |
909 | } | |
fc13020e DV |
910 | |
911 | /** | |
912 | * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the | |
913 | * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific | |
914 | * preparations. Coherency is only guaranteed in the specified range for the | |
915 | * specified access direction. | |
efb4df82 | 916 | * @dmabuf: [in] buffer to prepare cpu access for. |
fc13020e DV |
917 | * @direction: [in] length of range for cpu access. |
918 | * | |
0959a168 DV |
919 | * After the cpu access is complete the caller should call |
920 | * dma_buf_end_cpu_access(). Only when cpu access is braketed by both calls is | |
921 | * it guaranteed to be coherent with other DMA access. | |
922 | * | |
fc13020e DV |
923 | * Can return negative error values, returns 0 on success. |
924 | */ | |
831e9da7 | 925 | int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, |
fc13020e DV |
926 | enum dma_data_direction direction) |
927 | { | |
928 | int ret = 0; | |
929 | ||
930 | if (WARN_ON(!dmabuf)) | |
931 | return -EINVAL; | |
932 | ||
933 | if (dmabuf->ops->begin_cpu_access) | |
831e9da7 | 934 | ret = dmabuf->ops->begin_cpu_access(dmabuf, direction); |
fc13020e | 935 | |
ae4e46b1 CW |
936 | /* Ensure that all fences are waited upon - but we first allow |
937 | * the native handler the chance to do so more efficiently if it | |
938 | * chooses. A double invocation here will be reasonably cheap no-op. | |
939 | */ | |
940 | if (ret == 0) | |
941 | ret = __dma_buf_begin_cpu_access(dmabuf, direction); | |
942 | ||
fc13020e DV |
943 | return ret; |
944 | } | |
945 | EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access); | |
946 | ||
947 | /** | |
948 | * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the | |
949 | * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific | |
950 | * actions. Coherency is only guaranteed in the specified range for the | |
951 | * specified access direction. | |
efb4df82 | 952 | * @dmabuf: [in] buffer to complete cpu access for. |
fc13020e DV |
953 | * @direction: [in] length of range for cpu access. |
954 | * | |
0959a168 DV |
955 | * This terminates CPU access started with dma_buf_begin_cpu_access(). |
956 | * | |
87e332d5 | 957 | * Can return negative error values, returns 0 on success. |
fc13020e | 958 | */ |
18b862dc CW |
959 | int dma_buf_end_cpu_access(struct dma_buf *dmabuf, |
960 | enum dma_data_direction direction) | |
fc13020e | 961 | { |
18b862dc CW |
962 | int ret = 0; |
963 | ||
fc13020e DV |
964 | WARN_ON(!dmabuf); |
965 | ||
966 | if (dmabuf->ops->end_cpu_access) | |
18b862dc CW |
967 | ret = dmabuf->ops->end_cpu_access(dmabuf, direction); |
968 | ||
969 | return ret; | |
fc13020e DV |
970 | } |
971 | EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access); | |
972 | ||
fc13020e DV |
973 | /** |
974 | * dma_buf_kmap - Map a page of the buffer object into kernel address space. The | |
975 | * same restrictions as for kmap and friends apply. | |
efb4df82 | 976 | * @dmabuf: [in] buffer to map page from. |
fc13020e DV |
977 | * @page_num: [in] page in PAGE_SIZE units to map. |
978 | * | |
979 | * This call must always succeed, any necessary preparations that might fail | |
980 | * need to be done in begin_cpu_access. | |
981 | */ | |
982 | void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num) | |
983 | { | |
984 | WARN_ON(!dmabuf); | |
985 | ||
09ea0dfb GH |
986 | if (!dmabuf->ops->map) |
987 | return NULL; | |
f9b67f00 | 988 | return dmabuf->ops->map(dmabuf, page_num); |
fc13020e DV |
989 | } |
990 | EXPORT_SYMBOL_GPL(dma_buf_kmap); | |
991 | ||
992 | /** | |
993 | * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap. | |
efb4df82 | 994 | * @dmabuf: [in] buffer to unmap page from. |
fc13020e DV |
995 | * @page_num: [in] page in PAGE_SIZE units to unmap. |
996 | * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap. | |
997 | * | |
998 | * This call must always succeed. | |
999 | */ | |
1000 | void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num, | |
1001 | void *vaddr) | |
1002 | { | |
1003 | WARN_ON(!dmabuf); | |
1004 | ||
f9b67f00 LG |
1005 | if (dmabuf->ops->unmap) |
1006 | dmabuf->ops->unmap(dmabuf, page_num, vaddr); | |
fc13020e DV |
1007 | } |
1008 | EXPORT_SYMBOL_GPL(dma_buf_kunmap); | |
4c78513e DV |
1009 | |
1010 | ||
1011 | /** | |
1012 | * dma_buf_mmap - Setup up a userspace mmap with the given vma | |
12c4727e | 1013 | * @dmabuf: [in] buffer that should back the vma |
4c78513e DV |
1014 | * @vma: [in] vma for the mmap |
1015 | * @pgoff: [in] offset in pages where this mmap should start within the | |
5136629d | 1016 | * dma-buf buffer. |
4c78513e DV |
1017 | * |
1018 | * This function adjusts the passed in vma so that it points at the file of the | |
ecf1dbac | 1019 | * dma_buf operation. It also adjusts the starting pgoff and does bounds |
4c78513e DV |
1020 | * checking on the size of the vma. Then it calls the exporters mmap function to |
1021 | * set up the mapping. | |
1022 | * | |
1023 | * Can return negative error values, returns 0 on success. | |
1024 | */ | |
1025 | int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, | |
1026 | unsigned long pgoff) | |
1027 | { | |
495c10cc JS |
1028 | struct file *oldfile; |
1029 | int ret; | |
1030 | ||
4c78513e DV |
1031 | if (WARN_ON(!dmabuf || !vma)) |
1032 | return -EINVAL; | |
1033 | ||
e3a9d6c5 AD |
1034 | /* check if buffer supports mmap */ |
1035 | if (!dmabuf->ops->mmap) | |
1036 | return -EINVAL; | |
1037 | ||
4c78513e | 1038 | /* check for offset overflow */ |
b02da6f8 | 1039 | if (pgoff + vma_pages(vma) < pgoff) |
4c78513e DV |
1040 | return -EOVERFLOW; |
1041 | ||
1042 | /* check for overflowing the buffer's size */ | |
b02da6f8 | 1043 | if (pgoff + vma_pages(vma) > |
4c78513e DV |
1044 | dmabuf->size >> PAGE_SHIFT) |
1045 | return -EINVAL; | |
1046 | ||
1047 | /* readjust the vma */ | |
495c10cc JS |
1048 | get_file(dmabuf->file); |
1049 | oldfile = vma->vm_file; | |
1050 | vma->vm_file = dmabuf->file; | |
4c78513e DV |
1051 | vma->vm_pgoff = pgoff; |
1052 | ||
495c10cc JS |
1053 | ret = dmabuf->ops->mmap(dmabuf, vma); |
1054 | if (ret) { | |
1055 | /* restore old parameters on failure */ | |
1056 | vma->vm_file = oldfile; | |
1057 | fput(dmabuf->file); | |
1058 | } else { | |
1059 | if (oldfile) | |
1060 | fput(oldfile); | |
1061 | } | |
1062 | return ret; | |
1063 | ||
4c78513e DV |
1064 | } |
1065 | EXPORT_SYMBOL_GPL(dma_buf_mmap); | |
98f86c9e DA |
1066 | |
1067 | /** | |
12c4727e SS |
1068 | * dma_buf_vmap - Create virtual mapping for the buffer object into kernel |
1069 | * address space. Same restrictions as for vmap and friends apply. | |
1070 | * @dmabuf: [in] buffer to vmap | |
98f86c9e DA |
1071 | * |
1072 | * This call may fail due to lack of virtual mapping address space. | |
1073 | * These calls are optional in drivers. The intended use for them | |
1074 | * is for mapping objects linear in kernel space for high use objects. | |
1075 | * Please attempt to use kmap/kunmap before thinking about these interfaces. | |
fee0c54e CC |
1076 | * |
1077 | * Returns NULL on error. | |
98f86c9e DA |
1078 | */ |
1079 | void *dma_buf_vmap(struct dma_buf *dmabuf) | |
1080 | { | |
f00b4dad DV |
1081 | void *ptr; |
1082 | ||
98f86c9e DA |
1083 | if (WARN_ON(!dmabuf)) |
1084 | return NULL; | |
1085 | ||
f00b4dad DV |
1086 | if (!dmabuf->ops->vmap) |
1087 | return NULL; | |
1088 | ||
1089 | mutex_lock(&dmabuf->lock); | |
1090 | if (dmabuf->vmapping_counter) { | |
1091 | dmabuf->vmapping_counter++; | |
1092 | BUG_ON(!dmabuf->vmap_ptr); | |
1093 | ptr = dmabuf->vmap_ptr; | |
1094 | goto out_unlock; | |
1095 | } | |
1096 | ||
1097 | BUG_ON(dmabuf->vmap_ptr); | |
1098 | ||
1099 | ptr = dmabuf->ops->vmap(dmabuf); | |
fee0c54e CC |
1100 | if (WARN_ON_ONCE(IS_ERR(ptr))) |
1101 | ptr = NULL; | |
1102 | if (!ptr) | |
f00b4dad DV |
1103 | goto out_unlock; |
1104 | ||
1105 | dmabuf->vmap_ptr = ptr; | |
1106 | dmabuf->vmapping_counter = 1; | |
1107 | ||
1108 | out_unlock: | |
1109 | mutex_unlock(&dmabuf->lock); | |
1110 | return ptr; | |
98f86c9e DA |
1111 | } |
1112 | EXPORT_SYMBOL_GPL(dma_buf_vmap); | |
1113 | ||
1114 | /** | |
1115 | * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap. | |
12c4727e | 1116 | * @dmabuf: [in] buffer to vunmap |
6e7b4a59 | 1117 | * @vaddr: [in] vmap to vunmap |
98f86c9e DA |
1118 | */ |
1119 | void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr) | |
1120 | { | |
1121 | if (WARN_ON(!dmabuf)) | |
1122 | return; | |
1123 | ||
f00b4dad DV |
1124 | BUG_ON(!dmabuf->vmap_ptr); |
1125 | BUG_ON(dmabuf->vmapping_counter == 0); | |
1126 | BUG_ON(dmabuf->vmap_ptr != vaddr); | |
1127 | ||
1128 | mutex_lock(&dmabuf->lock); | |
1129 | if (--dmabuf->vmapping_counter == 0) { | |
1130 | if (dmabuf->ops->vunmap) | |
1131 | dmabuf->ops->vunmap(dmabuf, vaddr); | |
1132 | dmabuf->vmap_ptr = NULL; | |
1133 | } | |
1134 | mutex_unlock(&dmabuf->lock); | |
98f86c9e DA |
1135 | } |
1136 | EXPORT_SYMBOL_GPL(dma_buf_vunmap); | |
b89e3563 SS |
1137 | |
1138 | #ifdef CONFIG_DEBUG_FS | |
eb0b947e | 1139 | static int dma_buf_debug_show(struct seq_file *s, void *unused) |
b89e3563 SS |
1140 | { |
1141 | int ret; | |
1142 | struct dma_buf *buf_obj; | |
1143 | struct dma_buf_attachment *attach_obj; | |
52791eee CK |
1144 | struct dma_resv *robj; |
1145 | struct dma_resv_list *fobj; | |
5eb2c72c | 1146 | struct dma_fence *fence; |
5eb2c72c | 1147 | int count = 0, attach_count, shared_count, i; |
b89e3563 SS |
1148 | size_t size = 0; |
1149 | ||
1150 | ret = mutex_lock_interruptible(&db_list.lock); | |
1151 | ||
1152 | if (ret) | |
1153 | return ret; | |
1154 | ||
c0b00a52 | 1155 | seq_puts(s, "\nDma-buf Objects:\n"); |
ed63bb1d GH |
1156 | seq_printf(s, "%-8s\t%-8s\t%-8s\t%-8s\texp_name\t%-8s\n", |
1157 | "size", "flags", "mode", "count", "ino"); | |
b89e3563 SS |
1158 | |
1159 | list_for_each_entry(buf_obj, &db_list.head, list_node) { | |
1160 | ret = mutex_lock_interruptible(&buf_obj->lock); | |
1161 | ||
1162 | if (ret) { | |
c0b00a52 SS |
1163 | seq_puts(s, |
1164 | "\tERROR locking buffer object: skipping\n"); | |
b89e3563 SS |
1165 | continue; |
1166 | } | |
1167 | ||
bb2bb903 | 1168 | seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\t%s\n", |
c0b00a52 | 1169 | buf_obj->size, |
b89e3563 | 1170 | buf_obj->file->f_flags, buf_obj->file->f_mode, |
a1f6dbac | 1171 | file_count(buf_obj->file), |
ed63bb1d | 1172 | buf_obj->exp_name, |
bb2bb903 GH |
1173 | file_inode(buf_obj->file)->i_ino, |
1174 | buf_obj->name ?: ""); | |
b89e3563 | 1175 | |
5eb2c72c | 1176 | robj = buf_obj->resv; |
67c97fb7 | 1177 | rcu_read_lock(); |
52791eee | 1178 | dma_resv_fences(robj, &fence, &fobj, &shared_count); |
67c97fb7 | 1179 | rcu_read_unlock(); |
5eb2c72c RK |
1180 | |
1181 | if (fence) | |
1182 | seq_printf(s, "\tExclusive fence: %s %s %ssignalled\n", | |
1183 | fence->ops->get_driver_name(fence), | |
1184 | fence->ops->get_timeline_name(fence), | |
1185 | dma_fence_is_signaled(fence) ? "" : "un"); | |
1186 | for (i = 0; i < shared_count; i++) { | |
1187 | fence = rcu_dereference(fobj->shared[i]); | |
1188 | if (!dma_fence_get_rcu(fence)) | |
1189 | continue; | |
1190 | seq_printf(s, "\tShared fence: %s %s %ssignalled\n", | |
1191 | fence->ops->get_driver_name(fence), | |
1192 | fence->ops->get_timeline_name(fence), | |
1193 | dma_fence_is_signaled(fence) ? "" : "un"); | |
5e383a97 | 1194 | dma_fence_put(fence); |
5eb2c72c RK |
1195 | } |
1196 | rcu_read_unlock(); | |
1197 | ||
c0b00a52 | 1198 | seq_puts(s, "\tAttached Devices:\n"); |
b89e3563 SS |
1199 | attach_count = 0; |
1200 | ||
1201 | list_for_each_entry(attach_obj, &buf_obj->attachments, node) { | |
9eddb41d | 1202 | seq_printf(s, "\t%s\n", dev_name(attach_obj->dev)); |
b89e3563 SS |
1203 | attach_count++; |
1204 | } | |
1205 | ||
c0b00a52 | 1206 | seq_printf(s, "Total %d devices attached\n\n", |
b89e3563 SS |
1207 | attach_count); |
1208 | ||
1209 | count++; | |
1210 | size += buf_obj->size; | |
1211 | mutex_unlock(&buf_obj->lock); | |
1212 | } | |
1213 | ||
1214 | seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size); | |
1215 | ||
1216 | mutex_unlock(&db_list.lock); | |
1217 | return 0; | |
1218 | } | |
1219 | ||
2674305a | 1220 | DEFINE_SHOW_ATTRIBUTE(dma_buf_debug); |
b89e3563 SS |
1221 | |
1222 | static struct dentry *dma_buf_debugfs_dir; | |
1223 | ||
1224 | static int dma_buf_init_debugfs(void) | |
1225 | { | |
bd3e2208 | 1226 | struct dentry *d; |
b89e3563 | 1227 | int err = 0; |
5136629d | 1228 | |
bd3e2208 MK |
1229 | d = debugfs_create_dir("dma_buf", NULL); |
1230 | if (IS_ERR(d)) | |
1231 | return PTR_ERR(d); | |
5136629d | 1232 | |
bd3e2208 | 1233 | dma_buf_debugfs_dir = d; |
b89e3563 | 1234 | |
bd3e2208 MK |
1235 | d = debugfs_create_file("bufinfo", S_IRUGO, dma_buf_debugfs_dir, |
1236 | NULL, &dma_buf_debug_fops); | |
1237 | if (IS_ERR(d)) { | |
b89e3563 | 1238 | pr_debug("dma_buf: debugfs: failed to create node bufinfo\n"); |
b7479990 MK |
1239 | debugfs_remove_recursive(dma_buf_debugfs_dir); |
1240 | dma_buf_debugfs_dir = NULL; | |
bd3e2208 | 1241 | err = PTR_ERR(d); |
b7479990 | 1242 | } |
b89e3563 SS |
1243 | |
1244 | return err; | |
1245 | } | |
1246 | ||
1247 | static void dma_buf_uninit_debugfs(void) | |
1248 | { | |
298b6a81 | 1249 | debugfs_remove_recursive(dma_buf_debugfs_dir); |
b89e3563 | 1250 | } |
b89e3563 SS |
1251 | #else |
1252 | static inline int dma_buf_init_debugfs(void) | |
1253 | { | |
1254 | return 0; | |
1255 | } | |
1256 | static inline void dma_buf_uninit_debugfs(void) | |
1257 | { | |
1258 | } | |
1259 | #endif | |
1260 | ||
1261 | static int __init dma_buf_init(void) | |
1262 | { | |
ed63bb1d GH |
1263 | dma_buf_mnt = kern_mount(&dma_buf_fs_type); |
1264 | if (IS_ERR(dma_buf_mnt)) | |
1265 | return PTR_ERR(dma_buf_mnt); | |
1266 | ||
b89e3563 SS |
1267 | mutex_init(&db_list.lock); |
1268 | INIT_LIST_HEAD(&db_list.head); | |
1269 | dma_buf_init_debugfs(); | |
1270 | return 0; | |
1271 | } | |
1272 | subsys_initcall(dma_buf_init); | |
1273 | ||
1274 | static void __exit dma_buf_deinit(void) | |
1275 | { | |
1276 | dma_buf_uninit_debugfs(); | |
ed63bb1d | 1277 | kern_unmount(dma_buf_mnt); |
b89e3563 SS |
1278 | } |
1279 | __exitcall(dma_buf_deinit); |