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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> | |
28 | #include <linux/anon_inodes.h> | |
29 | #include <linux/export.h> | |
30 | ||
31 | static inline int is_dma_buf_file(struct file *); | |
32 | ||
33 | static int dma_buf_release(struct inode *inode, struct file *file) | |
34 | { | |
35 | struct dma_buf *dmabuf; | |
36 | ||
37 | if (!is_dma_buf_file(file)) | |
38 | return -EINVAL; | |
39 | ||
40 | dmabuf = file->private_data; | |
41 | ||
42 | dmabuf->ops->release(dmabuf); | |
43 | kfree(dmabuf); | |
44 | return 0; | |
45 | } | |
46 | ||
47 | static const struct file_operations dma_buf_fops = { | |
48 | .release = dma_buf_release, | |
49 | }; | |
50 | ||
51 | /* | |
52 | * is_dma_buf_file - Check if struct file* is associated with dma_buf | |
53 | */ | |
54 | static inline int is_dma_buf_file(struct file *file) | |
55 | { | |
56 | return file->f_op == &dma_buf_fops; | |
57 | } | |
58 | ||
59 | /** | |
60 | * dma_buf_export - Creates a new dma_buf, and associates an anon file | |
61 | * with this buffer, so it can be exported. | |
62 | * Also connect the allocator specific data and ops to the buffer. | |
63 | * | |
64 | * @priv: [in] Attach private data of allocator to this buffer | |
65 | * @ops: [in] Attach allocator-defined dma buf ops to the new buffer. | |
66 | * @size: [in] Size of the buffer | |
67 | * @flags: [in] mode flags for the file. | |
68 | * | |
69 | * Returns, on success, a newly created dma_buf object, which wraps the | |
70 | * supplied private data and operations for dma_buf_ops. On either missing | |
71 | * ops, or error in allocating struct dma_buf, will return negative error. | |
72 | * | |
73 | */ | |
5375764f | 74 | struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops, |
d15bd7ee SS |
75 | size_t size, int flags) |
76 | { | |
77 | struct dma_buf *dmabuf; | |
78 | struct file *file; | |
79 | ||
80 | if (WARN_ON(!priv || !ops | |
81 | || !ops->map_dma_buf | |
82 | || !ops->unmap_dma_buf | |
fc13020e DV |
83 | || !ops->release |
84 | || !ops->kmap_atomic | |
85 | || !ops->kmap)) { | |
d15bd7ee SS |
86 | return ERR_PTR(-EINVAL); |
87 | } | |
88 | ||
89 | dmabuf = kzalloc(sizeof(struct dma_buf), GFP_KERNEL); | |
90 | if (dmabuf == NULL) | |
91 | return ERR_PTR(-ENOMEM); | |
92 | ||
93 | dmabuf->priv = priv; | |
94 | dmabuf->ops = ops; | |
95 | dmabuf->size = size; | |
96 | ||
97 | file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, flags); | |
98 | ||
99 | dmabuf->file = file; | |
100 | ||
101 | mutex_init(&dmabuf->lock); | |
102 | INIT_LIST_HEAD(&dmabuf->attachments); | |
103 | ||
104 | return dmabuf; | |
105 | } | |
106 | EXPORT_SYMBOL_GPL(dma_buf_export); | |
107 | ||
108 | ||
109 | /** | |
110 | * dma_buf_fd - returns a file descriptor for the given dma_buf | |
111 | * @dmabuf: [in] pointer to dma_buf for which fd is required. | |
55c1c4ca | 112 | * @flags: [in] flags to give to fd |
d15bd7ee SS |
113 | * |
114 | * On success, returns an associated 'fd'. Else, returns error. | |
115 | */ | |
55c1c4ca | 116 | int dma_buf_fd(struct dma_buf *dmabuf, int flags) |
d15bd7ee SS |
117 | { |
118 | int error, fd; | |
119 | ||
120 | if (!dmabuf || !dmabuf->file) | |
121 | return -EINVAL; | |
122 | ||
55c1c4ca | 123 | error = get_unused_fd_flags(flags); |
d15bd7ee SS |
124 | if (error < 0) |
125 | return error; | |
126 | fd = error; | |
127 | ||
128 | fd_install(fd, dmabuf->file); | |
129 | ||
130 | return fd; | |
131 | } | |
132 | EXPORT_SYMBOL_GPL(dma_buf_fd); | |
133 | ||
134 | /** | |
135 | * dma_buf_get - returns the dma_buf structure related to an fd | |
136 | * @fd: [in] fd associated with the dma_buf to be returned | |
137 | * | |
138 | * On success, returns the dma_buf structure associated with an fd; uses | |
139 | * file's refcounting done by fget to increase refcount. returns ERR_PTR | |
140 | * otherwise. | |
141 | */ | |
142 | struct dma_buf *dma_buf_get(int fd) | |
143 | { | |
144 | struct file *file; | |
145 | ||
146 | file = fget(fd); | |
147 | ||
148 | if (!file) | |
149 | return ERR_PTR(-EBADF); | |
150 | ||
151 | if (!is_dma_buf_file(file)) { | |
152 | fput(file); | |
153 | return ERR_PTR(-EINVAL); | |
154 | } | |
155 | ||
156 | return file->private_data; | |
157 | } | |
158 | EXPORT_SYMBOL_GPL(dma_buf_get); | |
159 | ||
160 | /** | |
161 | * dma_buf_put - decreases refcount of the buffer | |
162 | * @dmabuf: [in] buffer to reduce refcount of | |
163 | * | |
164 | * Uses file's refcounting done implicitly by fput() | |
165 | */ | |
166 | void dma_buf_put(struct dma_buf *dmabuf) | |
167 | { | |
168 | if (WARN_ON(!dmabuf || !dmabuf->file)) | |
169 | return; | |
170 | ||
171 | fput(dmabuf->file); | |
172 | } | |
173 | EXPORT_SYMBOL_GPL(dma_buf_put); | |
174 | ||
175 | /** | |
176 | * dma_buf_attach - Add the device to dma_buf's attachments list; optionally, | |
177 | * calls attach() of dma_buf_ops to allow device-specific attach functionality | |
178 | * @dmabuf: [in] buffer to attach device to. | |
179 | * @dev: [in] device to be attached. | |
180 | * | |
181 | * Returns struct dma_buf_attachment * for this attachment; may return negative | |
182 | * error codes. | |
183 | * | |
184 | */ | |
185 | struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, | |
186 | struct device *dev) | |
187 | { | |
188 | struct dma_buf_attachment *attach; | |
189 | int ret; | |
190 | ||
d1aa06a1 | 191 | if (WARN_ON(!dmabuf || !dev)) |
d15bd7ee SS |
192 | return ERR_PTR(-EINVAL); |
193 | ||
194 | attach = kzalloc(sizeof(struct dma_buf_attachment), GFP_KERNEL); | |
195 | if (attach == NULL) | |
a9fbc3b7 | 196 | return ERR_PTR(-ENOMEM); |
d15bd7ee | 197 | |
d15bd7ee SS |
198 | attach->dev = dev; |
199 | attach->dmabuf = dmabuf; | |
2ed9201b LP |
200 | |
201 | mutex_lock(&dmabuf->lock); | |
202 | ||
d15bd7ee SS |
203 | if (dmabuf->ops->attach) { |
204 | ret = dmabuf->ops->attach(dmabuf, dev, attach); | |
205 | if (ret) | |
206 | goto err_attach; | |
207 | } | |
208 | list_add(&attach->node, &dmabuf->attachments); | |
209 | ||
210 | mutex_unlock(&dmabuf->lock); | |
211 | return attach; | |
212 | ||
d15bd7ee SS |
213 | err_attach: |
214 | kfree(attach); | |
215 | mutex_unlock(&dmabuf->lock); | |
216 | return ERR_PTR(ret); | |
217 | } | |
218 | EXPORT_SYMBOL_GPL(dma_buf_attach); | |
219 | ||
220 | /** | |
221 | * dma_buf_detach - Remove the given attachment from dmabuf's attachments list; | |
222 | * optionally calls detach() of dma_buf_ops for device-specific detach | |
223 | * @dmabuf: [in] buffer to detach from. | |
224 | * @attach: [in] attachment to be detached; is free'd after this call. | |
225 | * | |
226 | */ | |
227 | void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) | |
228 | { | |
d1aa06a1 | 229 | if (WARN_ON(!dmabuf || !attach)) |
d15bd7ee SS |
230 | return; |
231 | ||
232 | mutex_lock(&dmabuf->lock); | |
233 | list_del(&attach->node); | |
234 | if (dmabuf->ops->detach) | |
235 | dmabuf->ops->detach(dmabuf, attach); | |
236 | ||
237 | mutex_unlock(&dmabuf->lock); | |
238 | kfree(attach); | |
239 | } | |
240 | EXPORT_SYMBOL_GPL(dma_buf_detach); | |
241 | ||
242 | /** | |
243 | * dma_buf_map_attachment - Returns the scatterlist table of the attachment; | |
244 | * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the | |
245 | * dma_buf_ops. | |
246 | * @attach: [in] attachment whose scatterlist is to be returned | |
247 | * @direction: [in] direction of DMA transfer | |
248 | * | |
249 | * Returns sg_table containing the scatterlist to be returned; may return NULL | |
250 | * or ERR_PTR. | |
251 | * | |
252 | */ | |
253 | struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, | |
254 | enum dma_data_direction direction) | |
255 | { | |
256 | struct sg_table *sg_table = ERR_PTR(-EINVAL); | |
257 | ||
258 | might_sleep(); | |
259 | ||
d1aa06a1 | 260 | if (WARN_ON(!attach || !attach->dmabuf)) |
d15bd7ee SS |
261 | return ERR_PTR(-EINVAL); |
262 | ||
d1aa06a1 | 263 | sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction); |
d15bd7ee SS |
264 | |
265 | return sg_table; | |
266 | } | |
267 | EXPORT_SYMBOL_GPL(dma_buf_map_attachment); | |
268 | ||
269 | /** | |
270 | * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might | |
271 | * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of | |
272 | * dma_buf_ops. | |
273 | * @attach: [in] attachment to unmap buffer from | |
274 | * @sg_table: [in] scatterlist info of the buffer to unmap | |
33ea2dcb | 275 | * @direction: [in] direction of DMA transfer |
d15bd7ee SS |
276 | * |
277 | */ | |
278 | void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, | |
33ea2dcb SS |
279 | struct sg_table *sg_table, |
280 | enum dma_data_direction direction) | |
d15bd7ee | 281 | { |
d1aa06a1 | 282 | if (WARN_ON(!attach || !attach->dmabuf || !sg_table)) |
d15bd7ee SS |
283 | return; |
284 | ||
33ea2dcb SS |
285 | attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, |
286 | direction); | |
d15bd7ee SS |
287 | } |
288 | EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment); | |
fc13020e DV |
289 | |
290 | ||
291 | /** | |
292 | * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the | |
293 | * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific | |
294 | * preparations. Coherency is only guaranteed in the specified range for the | |
295 | * specified access direction. | |
296 | * @dma_buf: [in] buffer to prepare cpu access for. | |
297 | * @start: [in] start of range for cpu access. | |
298 | * @len: [in] length of range for cpu access. | |
299 | * @direction: [in] length of range for cpu access. | |
300 | * | |
301 | * Can return negative error values, returns 0 on success. | |
302 | */ | |
303 | int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len, | |
304 | enum dma_data_direction direction) | |
305 | { | |
306 | int ret = 0; | |
307 | ||
308 | if (WARN_ON(!dmabuf)) | |
309 | return -EINVAL; | |
310 | ||
311 | if (dmabuf->ops->begin_cpu_access) | |
312 | ret = dmabuf->ops->begin_cpu_access(dmabuf, start, len, direction); | |
313 | ||
314 | return ret; | |
315 | } | |
316 | EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access); | |
317 | ||
318 | /** | |
319 | * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the | |
320 | * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific | |
321 | * actions. Coherency is only guaranteed in the specified range for the | |
322 | * specified access direction. | |
323 | * @dma_buf: [in] buffer to complete cpu access for. | |
324 | * @start: [in] start of range for cpu access. | |
325 | * @len: [in] length of range for cpu access. | |
326 | * @direction: [in] length of range for cpu access. | |
327 | * | |
328 | * This call must always succeed. | |
329 | */ | |
330 | void dma_buf_end_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len, | |
331 | enum dma_data_direction direction) | |
332 | { | |
333 | WARN_ON(!dmabuf); | |
334 | ||
335 | if (dmabuf->ops->end_cpu_access) | |
336 | dmabuf->ops->end_cpu_access(dmabuf, start, len, direction); | |
337 | } | |
338 | EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access); | |
339 | ||
340 | /** | |
341 | * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address | |
342 | * space. The same restrictions as for kmap_atomic and friends apply. | |
343 | * @dma_buf: [in] buffer to map page from. | |
344 | * @page_num: [in] page in PAGE_SIZE units to map. | |
345 | * | |
346 | * This call must always succeed, any necessary preparations that might fail | |
347 | * need to be done in begin_cpu_access. | |
348 | */ | |
349 | void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num) | |
350 | { | |
351 | WARN_ON(!dmabuf); | |
352 | ||
353 | return dmabuf->ops->kmap_atomic(dmabuf, page_num); | |
354 | } | |
355 | EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic); | |
356 | ||
357 | /** | |
358 | * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic. | |
359 | * @dma_buf: [in] buffer to unmap page from. | |
360 | * @page_num: [in] page in PAGE_SIZE units to unmap. | |
361 | * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap_atomic. | |
362 | * | |
363 | * This call must always succeed. | |
364 | */ | |
365 | void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, unsigned long page_num, | |
366 | void *vaddr) | |
367 | { | |
368 | WARN_ON(!dmabuf); | |
369 | ||
370 | if (dmabuf->ops->kunmap_atomic) | |
371 | dmabuf->ops->kunmap_atomic(dmabuf, page_num, vaddr); | |
372 | } | |
373 | EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic); | |
374 | ||
375 | /** | |
376 | * dma_buf_kmap - Map a page of the buffer object into kernel address space. The | |
377 | * same restrictions as for kmap and friends apply. | |
378 | * @dma_buf: [in] buffer to map page from. | |
379 | * @page_num: [in] page in PAGE_SIZE units to map. | |
380 | * | |
381 | * This call must always succeed, any necessary preparations that might fail | |
382 | * need to be done in begin_cpu_access. | |
383 | */ | |
384 | void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num) | |
385 | { | |
386 | WARN_ON(!dmabuf); | |
387 | ||
388 | return dmabuf->ops->kmap(dmabuf, page_num); | |
389 | } | |
390 | EXPORT_SYMBOL_GPL(dma_buf_kmap); | |
391 | ||
392 | /** | |
393 | * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap. | |
394 | * @dma_buf: [in] buffer to unmap page from. | |
395 | * @page_num: [in] page in PAGE_SIZE units to unmap. | |
396 | * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap. | |
397 | * | |
398 | * This call must always succeed. | |
399 | */ | |
400 | void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num, | |
401 | void *vaddr) | |
402 | { | |
403 | WARN_ON(!dmabuf); | |
404 | ||
405 | if (dmabuf->ops->kunmap) | |
406 | dmabuf->ops->kunmap(dmabuf, page_num, vaddr); | |
407 | } | |
408 | EXPORT_SYMBOL_GPL(dma_buf_kunmap); |