2 * Framework for buffer objects that can be shared across devices/subsystems.
4 * Copyright(C) 2011 Linaro Limited. All rights reserved.
5 * Author: Sumit Semwal <sumit.semwal@ti.com>
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.
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.
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
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/>.
26 #include <linux/slab.h>
27 #include <linux/dma-buf.h>
28 #include <linux/anon_inodes.h>
29 #include <linux/export.h>
31 static inline int is_dma_buf_file(struct file
*);
33 static int dma_buf_release(struct inode
*inode
, struct file
*file
)
35 struct dma_buf
*dmabuf
;
37 if (!is_dma_buf_file(file
))
40 dmabuf
= file
->private_data
;
42 dmabuf
->ops
->release(dmabuf
);
47 static int dma_buf_mmap_internal(struct file
*file
, struct vm_area_struct
*vma
)
49 struct dma_buf
*dmabuf
;
51 if (!is_dma_buf_file(file
))
54 dmabuf
= file
->private_data
;
56 /* check for overflowing the buffer's size */
57 if (vma
->vm_pgoff
+ ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
) >
58 dmabuf
->size
>> PAGE_SHIFT
)
61 return dmabuf
->ops
->mmap(dmabuf
, vma
);
64 static const struct file_operations dma_buf_fops
= {
65 .release
= dma_buf_release
,
66 .mmap
= dma_buf_mmap_internal
,
70 * is_dma_buf_file - Check if struct file* is associated with dma_buf
72 static inline int is_dma_buf_file(struct file
*file
)
74 return file
->f_op
== &dma_buf_fops
;
78 * dma_buf_export - Creates a new dma_buf, and associates an anon file
79 * with this buffer, so it can be exported.
80 * Also connect the allocator specific data and ops to the buffer.
82 * @priv: [in] Attach private data of allocator to this buffer
83 * @ops: [in] Attach allocator-defined dma buf ops to the new buffer.
84 * @size: [in] Size of the buffer
85 * @flags: [in] mode flags for the file.
87 * Returns, on success, a newly created dma_buf object, which wraps the
88 * supplied private data and operations for dma_buf_ops. On either missing
89 * ops, or error in allocating struct dma_buf, will return negative error.
92 struct dma_buf
*dma_buf_export(void *priv
, const struct dma_buf_ops
*ops
,
93 size_t size
, int flags
)
95 struct dma_buf
*dmabuf
;
98 if (WARN_ON(!priv
|| !ops
100 || !ops
->unmap_dma_buf
105 return ERR_PTR(-EINVAL
);
108 dmabuf
= kzalloc(sizeof(struct dma_buf
), GFP_KERNEL
);
110 return ERR_PTR(-ENOMEM
);
116 file
= anon_inode_getfile("dmabuf", &dma_buf_fops
, dmabuf
, flags
);
120 mutex_init(&dmabuf
->lock
);
121 INIT_LIST_HEAD(&dmabuf
->attachments
);
125 EXPORT_SYMBOL_GPL(dma_buf_export
);
129 * dma_buf_fd - returns a file descriptor for the given dma_buf
130 * @dmabuf: [in] pointer to dma_buf for which fd is required.
131 * @flags: [in] flags to give to fd
133 * On success, returns an associated 'fd'. Else, returns error.
135 int dma_buf_fd(struct dma_buf
*dmabuf
, int flags
)
139 if (!dmabuf
|| !dmabuf
->file
)
142 fd
= get_unused_fd_flags(flags
);
146 fd_install(fd
, dmabuf
->file
);
150 EXPORT_SYMBOL_GPL(dma_buf_fd
);
153 * dma_buf_get - returns the dma_buf structure related to an fd
154 * @fd: [in] fd associated with the dma_buf to be returned
156 * On success, returns the dma_buf structure associated with an fd; uses
157 * file's refcounting done by fget to increase refcount. returns ERR_PTR
160 struct dma_buf
*dma_buf_get(int fd
)
167 return ERR_PTR(-EBADF
);
169 if (!is_dma_buf_file(file
)) {
171 return ERR_PTR(-EINVAL
);
174 return file
->private_data
;
176 EXPORT_SYMBOL_GPL(dma_buf_get
);
179 * dma_buf_put - decreases refcount of the buffer
180 * @dmabuf: [in] buffer to reduce refcount of
182 * Uses file's refcounting done implicitly by fput()
184 void dma_buf_put(struct dma_buf
*dmabuf
)
186 if (WARN_ON(!dmabuf
|| !dmabuf
->file
))
191 EXPORT_SYMBOL_GPL(dma_buf_put
);
194 * dma_buf_attach - Add the device to dma_buf's attachments list; optionally,
195 * calls attach() of dma_buf_ops to allow device-specific attach functionality
196 * @dmabuf: [in] buffer to attach device to.
197 * @dev: [in] device to be attached.
199 * Returns struct dma_buf_attachment * for this attachment; may return negative
203 struct dma_buf_attachment
*dma_buf_attach(struct dma_buf
*dmabuf
,
206 struct dma_buf_attachment
*attach
;
209 if (WARN_ON(!dmabuf
|| !dev
))
210 return ERR_PTR(-EINVAL
);
212 attach
= kzalloc(sizeof(struct dma_buf_attachment
), GFP_KERNEL
);
214 return ERR_PTR(-ENOMEM
);
217 attach
->dmabuf
= dmabuf
;
219 mutex_lock(&dmabuf
->lock
);
221 if (dmabuf
->ops
->attach
) {
222 ret
= dmabuf
->ops
->attach(dmabuf
, dev
, attach
);
226 list_add(&attach
->node
, &dmabuf
->attachments
);
228 mutex_unlock(&dmabuf
->lock
);
233 mutex_unlock(&dmabuf
->lock
);
236 EXPORT_SYMBOL_GPL(dma_buf_attach
);
239 * dma_buf_detach - Remove the given attachment from dmabuf's attachments list;
240 * optionally calls detach() of dma_buf_ops for device-specific detach
241 * @dmabuf: [in] buffer to detach from.
242 * @attach: [in] attachment to be detached; is free'd after this call.
245 void dma_buf_detach(struct dma_buf
*dmabuf
, struct dma_buf_attachment
*attach
)
247 if (WARN_ON(!dmabuf
|| !attach
))
250 mutex_lock(&dmabuf
->lock
);
251 list_del(&attach
->node
);
252 if (dmabuf
->ops
->detach
)
253 dmabuf
->ops
->detach(dmabuf
, attach
);
255 mutex_unlock(&dmabuf
->lock
);
258 EXPORT_SYMBOL_GPL(dma_buf_detach
);
261 * dma_buf_map_attachment - Returns the scatterlist table of the attachment;
262 * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
264 * @attach: [in] attachment whose scatterlist is to be returned
265 * @direction: [in] direction of DMA transfer
267 * Returns sg_table containing the scatterlist to be returned; may return NULL
271 struct sg_table
*dma_buf_map_attachment(struct dma_buf_attachment
*attach
,
272 enum dma_data_direction direction
)
274 struct sg_table
*sg_table
= ERR_PTR(-EINVAL
);
278 if (WARN_ON(!attach
|| !attach
->dmabuf
))
279 return ERR_PTR(-EINVAL
);
281 sg_table
= attach
->dmabuf
->ops
->map_dma_buf(attach
, direction
);
285 EXPORT_SYMBOL_GPL(dma_buf_map_attachment
);
288 * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
289 * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
291 * @attach: [in] attachment to unmap buffer from
292 * @sg_table: [in] scatterlist info of the buffer to unmap
293 * @direction: [in] direction of DMA transfer
296 void dma_buf_unmap_attachment(struct dma_buf_attachment
*attach
,
297 struct sg_table
*sg_table
,
298 enum dma_data_direction direction
)
302 if (WARN_ON(!attach
|| !attach
->dmabuf
|| !sg_table
))
305 attach
->dmabuf
->ops
->unmap_dma_buf(attach
, sg_table
,
308 EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment
);
312 * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
313 * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific
314 * preparations. Coherency is only guaranteed in the specified range for the
315 * specified access direction.
316 * @dmabuf: [in] buffer to prepare cpu access for.
317 * @start: [in] start of range for cpu access.
318 * @len: [in] length of range for cpu access.
319 * @direction: [in] length of range for cpu access.
321 * Can return negative error values, returns 0 on success.
323 int dma_buf_begin_cpu_access(struct dma_buf
*dmabuf
, size_t start
, size_t len
,
324 enum dma_data_direction direction
)
328 if (WARN_ON(!dmabuf
))
331 if (dmabuf
->ops
->begin_cpu_access
)
332 ret
= dmabuf
->ops
->begin_cpu_access(dmabuf
, start
, len
, direction
);
336 EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access
);
339 * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the
340 * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific
341 * actions. Coherency is only guaranteed in the specified range for the
342 * specified access direction.
343 * @dmabuf: [in] buffer to complete cpu access for.
344 * @start: [in] start of range for cpu access.
345 * @len: [in] length of range for cpu access.
346 * @direction: [in] length of range for cpu access.
348 * This call must always succeed.
350 void dma_buf_end_cpu_access(struct dma_buf
*dmabuf
, size_t start
, size_t len
,
351 enum dma_data_direction direction
)
355 if (dmabuf
->ops
->end_cpu_access
)
356 dmabuf
->ops
->end_cpu_access(dmabuf
, start
, len
, direction
);
358 EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access
);
361 * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address
362 * space. The same restrictions as for kmap_atomic and friends apply.
363 * @dmabuf: [in] buffer to map page from.
364 * @page_num: [in] page in PAGE_SIZE units to map.
366 * This call must always succeed, any necessary preparations that might fail
367 * need to be done in begin_cpu_access.
369 void *dma_buf_kmap_atomic(struct dma_buf
*dmabuf
, unsigned long page_num
)
373 return dmabuf
->ops
->kmap_atomic(dmabuf
, page_num
);
375 EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic
);
378 * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic.
379 * @dmabuf: [in] buffer to unmap page from.
380 * @page_num: [in] page in PAGE_SIZE units to unmap.
381 * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap_atomic.
383 * This call must always succeed.
385 void dma_buf_kunmap_atomic(struct dma_buf
*dmabuf
, unsigned long page_num
,
390 if (dmabuf
->ops
->kunmap_atomic
)
391 dmabuf
->ops
->kunmap_atomic(dmabuf
, page_num
, vaddr
);
393 EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic
);
396 * dma_buf_kmap - Map a page of the buffer object into kernel address space. The
397 * same restrictions as for kmap and friends apply.
398 * @dmabuf: [in] buffer to map page from.
399 * @page_num: [in] page in PAGE_SIZE units to map.
401 * This call must always succeed, any necessary preparations that might fail
402 * need to be done in begin_cpu_access.
404 void *dma_buf_kmap(struct dma_buf
*dmabuf
, unsigned long page_num
)
408 return dmabuf
->ops
->kmap(dmabuf
, page_num
);
410 EXPORT_SYMBOL_GPL(dma_buf_kmap
);
413 * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap.
414 * @dmabuf: [in] buffer to unmap page from.
415 * @page_num: [in] page in PAGE_SIZE units to unmap.
416 * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap.
418 * This call must always succeed.
420 void dma_buf_kunmap(struct dma_buf
*dmabuf
, unsigned long page_num
,
425 if (dmabuf
->ops
->kunmap
)
426 dmabuf
->ops
->kunmap(dmabuf
, page_num
, vaddr
);
428 EXPORT_SYMBOL_GPL(dma_buf_kunmap
);
432 * dma_buf_mmap - Setup up a userspace mmap with the given vma
433 * @dmabuf: [in] buffer that should back the vma
434 * @vma: [in] vma for the mmap
435 * @pgoff: [in] offset in pages where this mmap should start within the
438 * This function adjusts the passed in vma so that it points at the file of the
439 * dma_buf operation. It alsog adjusts the starting pgoff and does bounds
440 * checking on the size of the vma. Then it calls the exporters mmap function to
441 * set up the mapping.
443 * Can return negative error values, returns 0 on success.
445 int dma_buf_mmap(struct dma_buf
*dmabuf
, struct vm_area_struct
*vma
,
448 if (WARN_ON(!dmabuf
|| !vma
))
451 /* check for offset overflow */
452 if (pgoff
+ ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
) < pgoff
)
455 /* check for overflowing the buffer's size */
456 if (pgoff
+ ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
) >
457 dmabuf
->size
>> PAGE_SHIFT
)
460 /* readjust the vma */
464 vma
->vm_file
= get_file(dmabuf
->file
);
466 vma
->vm_pgoff
= pgoff
;
468 return dmabuf
->ops
->mmap(dmabuf
, vma
);
470 EXPORT_SYMBOL_GPL(dma_buf_mmap
);
473 * dma_buf_vmap - Create virtual mapping for the buffer object into kernel
474 * address space. Same restrictions as for vmap and friends apply.
475 * @dmabuf: [in] buffer to vmap
477 * This call may fail due to lack of virtual mapping address space.
478 * These calls are optional in drivers. The intended use for them
479 * is for mapping objects linear in kernel space for high use objects.
480 * Please attempt to use kmap/kunmap before thinking about these interfaces.
482 void *dma_buf_vmap(struct dma_buf
*dmabuf
)
484 if (WARN_ON(!dmabuf
))
487 if (dmabuf
->ops
->vmap
)
488 return dmabuf
->ops
->vmap(dmabuf
);
491 EXPORT_SYMBOL_GPL(dma_buf_vmap
);
494 * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
495 * @dmabuf: [in] buffer to vunmap
496 * @vaddr: [in] vmap to vunmap
498 void dma_buf_vunmap(struct dma_buf
*dmabuf
, void *vaddr
)
500 if (WARN_ON(!dmabuf
))
503 if (dmabuf
->ops
->vunmap
)
504 dmabuf
->ops
->vunmap(dmabuf
, vaddr
);
506 EXPORT_SYMBOL_GPL(dma_buf_vunmap
);