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 BUG_ON(dmabuf
->vmapping_counter
);
44 dmabuf
->ops
->release(dmabuf
);
49 static int dma_buf_mmap_internal(struct file
*file
, struct vm_area_struct
*vma
)
51 struct dma_buf
*dmabuf
;
53 if (!is_dma_buf_file(file
))
56 dmabuf
= file
->private_data
;
58 /* check for overflowing the buffer's size */
59 if (vma
->vm_pgoff
+ ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
) >
60 dmabuf
->size
>> PAGE_SHIFT
)
63 return dmabuf
->ops
->mmap(dmabuf
, vma
);
66 static const struct file_operations dma_buf_fops
= {
67 .release
= dma_buf_release
,
68 .mmap
= dma_buf_mmap_internal
,
72 * is_dma_buf_file - Check if struct file* is associated with dma_buf
74 static inline int is_dma_buf_file(struct file
*file
)
76 return file
->f_op
== &dma_buf_fops
;
80 * dma_buf_export - Creates a new dma_buf, and associates an anon file
81 * with this buffer, so it can be exported.
82 * Also connect the allocator specific data and ops to the buffer.
84 * @priv: [in] Attach private data of allocator to this buffer
85 * @ops: [in] Attach allocator-defined dma buf ops to the new buffer.
86 * @size: [in] Size of the buffer
87 * @flags: [in] mode flags for the file.
89 * Returns, on success, a newly created dma_buf object, which wraps the
90 * supplied private data and operations for dma_buf_ops. On either missing
91 * ops, or error in allocating struct dma_buf, will return negative error.
94 struct dma_buf
*dma_buf_export(void *priv
, const struct dma_buf_ops
*ops
,
95 size_t size
, int flags
)
97 struct dma_buf
*dmabuf
;
100 if (WARN_ON(!priv
|| !ops
102 || !ops
->unmap_dma_buf
107 return ERR_PTR(-EINVAL
);
110 dmabuf
= kzalloc(sizeof(struct dma_buf
), GFP_KERNEL
);
112 return ERR_PTR(-ENOMEM
);
118 file
= anon_inode_getfile("dmabuf", &dma_buf_fops
, dmabuf
, flags
);
122 mutex_init(&dmabuf
->lock
);
123 INIT_LIST_HEAD(&dmabuf
->attachments
);
127 EXPORT_SYMBOL_GPL(dma_buf_export
);
131 * dma_buf_fd - returns a file descriptor for the given dma_buf
132 * @dmabuf: [in] pointer to dma_buf for which fd is required.
133 * @flags: [in] flags to give to fd
135 * On success, returns an associated 'fd'. Else, returns error.
137 int dma_buf_fd(struct dma_buf
*dmabuf
, int flags
)
141 if (!dmabuf
|| !dmabuf
->file
)
144 fd
= get_unused_fd_flags(flags
);
148 fd_install(fd
, dmabuf
->file
);
152 EXPORT_SYMBOL_GPL(dma_buf_fd
);
155 * dma_buf_get - returns the dma_buf structure related to an fd
156 * @fd: [in] fd associated with the dma_buf to be returned
158 * On success, returns the dma_buf structure associated with an fd; uses
159 * file's refcounting done by fget to increase refcount. returns ERR_PTR
162 struct dma_buf
*dma_buf_get(int fd
)
169 return ERR_PTR(-EBADF
);
171 if (!is_dma_buf_file(file
)) {
173 return ERR_PTR(-EINVAL
);
176 return file
->private_data
;
178 EXPORT_SYMBOL_GPL(dma_buf_get
);
181 * dma_buf_put - decreases refcount of the buffer
182 * @dmabuf: [in] buffer to reduce refcount of
184 * Uses file's refcounting done implicitly by fput()
186 void dma_buf_put(struct dma_buf
*dmabuf
)
188 if (WARN_ON(!dmabuf
|| !dmabuf
->file
))
193 EXPORT_SYMBOL_GPL(dma_buf_put
);
196 * dma_buf_attach - Add the device to dma_buf's attachments list; optionally,
197 * calls attach() of dma_buf_ops to allow device-specific attach functionality
198 * @dmabuf: [in] buffer to attach device to.
199 * @dev: [in] device to be attached.
201 * Returns struct dma_buf_attachment * for this attachment; may return negative
205 struct dma_buf_attachment
*dma_buf_attach(struct dma_buf
*dmabuf
,
208 struct dma_buf_attachment
*attach
;
211 if (WARN_ON(!dmabuf
|| !dev
))
212 return ERR_PTR(-EINVAL
);
214 attach
= kzalloc(sizeof(struct dma_buf_attachment
), GFP_KERNEL
);
216 return ERR_PTR(-ENOMEM
);
219 attach
->dmabuf
= dmabuf
;
221 mutex_lock(&dmabuf
->lock
);
223 if (dmabuf
->ops
->attach
) {
224 ret
= dmabuf
->ops
->attach(dmabuf
, dev
, attach
);
228 list_add(&attach
->node
, &dmabuf
->attachments
);
230 mutex_unlock(&dmabuf
->lock
);
235 mutex_unlock(&dmabuf
->lock
);
238 EXPORT_SYMBOL_GPL(dma_buf_attach
);
241 * dma_buf_detach - Remove the given attachment from dmabuf's attachments list;
242 * optionally calls detach() of dma_buf_ops for device-specific detach
243 * @dmabuf: [in] buffer to detach from.
244 * @attach: [in] attachment to be detached; is free'd after this call.
247 void dma_buf_detach(struct dma_buf
*dmabuf
, struct dma_buf_attachment
*attach
)
249 if (WARN_ON(!dmabuf
|| !attach
))
252 mutex_lock(&dmabuf
->lock
);
253 list_del(&attach
->node
);
254 if (dmabuf
->ops
->detach
)
255 dmabuf
->ops
->detach(dmabuf
, attach
);
257 mutex_unlock(&dmabuf
->lock
);
260 EXPORT_SYMBOL_GPL(dma_buf_detach
);
263 * dma_buf_map_attachment - Returns the scatterlist table of the attachment;
264 * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
266 * @attach: [in] attachment whose scatterlist is to be returned
267 * @direction: [in] direction of DMA transfer
269 * Returns sg_table containing the scatterlist to be returned; may return NULL
273 struct sg_table
*dma_buf_map_attachment(struct dma_buf_attachment
*attach
,
274 enum dma_data_direction direction
)
276 struct sg_table
*sg_table
= ERR_PTR(-EINVAL
);
280 if (WARN_ON(!attach
|| !attach
->dmabuf
))
281 return ERR_PTR(-EINVAL
);
283 sg_table
= attach
->dmabuf
->ops
->map_dma_buf(attach
, direction
);
287 EXPORT_SYMBOL_GPL(dma_buf_map_attachment
);
290 * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
291 * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
293 * @attach: [in] attachment to unmap buffer from
294 * @sg_table: [in] scatterlist info of the buffer to unmap
295 * @direction: [in] direction of DMA transfer
298 void dma_buf_unmap_attachment(struct dma_buf_attachment
*attach
,
299 struct sg_table
*sg_table
,
300 enum dma_data_direction direction
)
304 if (WARN_ON(!attach
|| !attach
->dmabuf
|| !sg_table
))
307 attach
->dmabuf
->ops
->unmap_dma_buf(attach
, sg_table
,
310 EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment
);
314 * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
315 * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific
316 * preparations. Coherency is only guaranteed in the specified range for the
317 * specified access direction.
318 * @dmabuf: [in] buffer to prepare cpu access for.
319 * @start: [in] start of range for cpu access.
320 * @len: [in] length of range for cpu access.
321 * @direction: [in] length of range for cpu access.
323 * Can return negative error values, returns 0 on success.
325 int dma_buf_begin_cpu_access(struct dma_buf
*dmabuf
, size_t start
, size_t len
,
326 enum dma_data_direction direction
)
330 if (WARN_ON(!dmabuf
))
333 if (dmabuf
->ops
->begin_cpu_access
)
334 ret
= dmabuf
->ops
->begin_cpu_access(dmabuf
, start
, len
, direction
);
338 EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access
);
341 * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the
342 * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific
343 * actions. Coherency is only guaranteed in the specified range for the
344 * specified access direction.
345 * @dmabuf: [in] buffer to complete cpu access for.
346 * @start: [in] start of range for cpu access.
347 * @len: [in] length of range for cpu access.
348 * @direction: [in] length of range for cpu access.
350 * This call must always succeed.
352 void dma_buf_end_cpu_access(struct dma_buf
*dmabuf
, size_t start
, size_t len
,
353 enum dma_data_direction direction
)
357 if (dmabuf
->ops
->end_cpu_access
)
358 dmabuf
->ops
->end_cpu_access(dmabuf
, start
, len
, direction
);
360 EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access
);
363 * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address
364 * space. The same restrictions as for kmap_atomic and friends apply.
365 * @dmabuf: [in] buffer to map page from.
366 * @page_num: [in] page in PAGE_SIZE units to map.
368 * This call must always succeed, any necessary preparations that might fail
369 * need to be done in begin_cpu_access.
371 void *dma_buf_kmap_atomic(struct dma_buf
*dmabuf
, unsigned long page_num
)
375 return dmabuf
->ops
->kmap_atomic(dmabuf
, page_num
);
377 EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic
);
380 * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic.
381 * @dmabuf: [in] buffer to unmap page from.
382 * @page_num: [in] page in PAGE_SIZE units to unmap.
383 * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap_atomic.
385 * This call must always succeed.
387 void dma_buf_kunmap_atomic(struct dma_buf
*dmabuf
, unsigned long page_num
,
392 if (dmabuf
->ops
->kunmap_atomic
)
393 dmabuf
->ops
->kunmap_atomic(dmabuf
, page_num
, vaddr
);
395 EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic
);
398 * dma_buf_kmap - Map a page of the buffer object into kernel address space. The
399 * same restrictions as for kmap and friends apply.
400 * @dmabuf: [in] buffer to map page from.
401 * @page_num: [in] page in PAGE_SIZE units to map.
403 * This call must always succeed, any necessary preparations that might fail
404 * need to be done in begin_cpu_access.
406 void *dma_buf_kmap(struct dma_buf
*dmabuf
, unsigned long page_num
)
410 return dmabuf
->ops
->kmap(dmabuf
, page_num
);
412 EXPORT_SYMBOL_GPL(dma_buf_kmap
);
415 * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap.
416 * @dmabuf: [in] buffer to unmap page from.
417 * @page_num: [in] page in PAGE_SIZE units to unmap.
418 * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap.
420 * This call must always succeed.
422 void dma_buf_kunmap(struct dma_buf
*dmabuf
, unsigned long page_num
,
427 if (dmabuf
->ops
->kunmap
)
428 dmabuf
->ops
->kunmap(dmabuf
, page_num
, vaddr
);
430 EXPORT_SYMBOL_GPL(dma_buf_kunmap
);
434 * dma_buf_mmap - Setup up a userspace mmap with the given vma
435 * @dmabuf: [in] buffer that should back the vma
436 * @vma: [in] vma for the mmap
437 * @pgoff: [in] offset in pages where this mmap should start within the
440 * This function adjusts the passed in vma so that it points at the file of the
441 * dma_buf operation. It alsog adjusts the starting pgoff and does bounds
442 * checking on the size of the vma. Then it calls the exporters mmap function to
443 * set up the mapping.
445 * Can return negative error values, returns 0 on success.
447 int dma_buf_mmap(struct dma_buf
*dmabuf
, struct vm_area_struct
*vma
,
450 if (WARN_ON(!dmabuf
|| !vma
))
453 /* check for offset overflow */
454 if (pgoff
+ ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
) < pgoff
)
457 /* check for overflowing the buffer's size */
458 if (pgoff
+ ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
) >
459 dmabuf
->size
>> PAGE_SHIFT
)
462 /* readjust the vma */
466 vma
->vm_file
= get_file(dmabuf
->file
);
468 vma
->vm_pgoff
= pgoff
;
470 return dmabuf
->ops
->mmap(dmabuf
, vma
);
472 EXPORT_SYMBOL_GPL(dma_buf_mmap
);
475 * dma_buf_vmap - Create virtual mapping for the buffer object into kernel
476 * address space. Same restrictions as for vmap and friends apply.
477 * @dmabuf: [in] buffer to vmap
479 * This call may fail due to lack of virtual mapping address space.
480 * These calls are optional in drivers. The intended use for them
481 * is for mapping objects linear in kernel space for high use objects.
482 * Please attempt to use kmap/kunmap before thinking about these interfaces.
484 void *dma_buf_vmap(struct dma_buf
*dmabuf
)
488 if (WARN_ON(!dmabuf
))
491 if (!dmabuf
->ops
->vmap
)
494 mutex_lock(&dmabuf
->lock
);
495 if (dmabuf
->vmapping_counter
) {
496 dmabuf
->vmapping_counter
++;
497 BUG_ON(!dmabuf
->vmap_ptr
);
498 ptr
= dmabuf
->vmap_ptr
;
502 BUG_ON(dmabuf
->vmap_ptr
);
504 ptr
= dmabuf
->ops
->vmap(dmabuf
);
505 if (IS_ERR_OR_NULL(ptr
))
508 dmabuf
->vmap_ptr
= ptr
;
509 dmabuf
->vmapping_counter
= 1;
512 mutex_unlock(&dmabuf
->lock
);
515 EXPORT_SYMBOL_GPL(dma_buf_vmap
);
518 * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
519 * @dmabuf: [in] buffer to vunmap
520 * @vaddr: [in] vmap to vunmap
522 void dma_buf_vunmap(struct dma_buf
*dmabuf
, void *vaddr
)
524 if (WARN_ON(!dmabuf
))
527 BUG_ON(!dmabuf
->vmap_ptr
);
528 BUG_ON(dmabuf
->vmapping_counter
== 0);
529 BUG_ON(dmabuf
->vmap_ptr
!= vaddr
);
531 mutex_lock(&dmabuf
->lock
);
532 if (--dmabuf
->vmapping_counter
== 0) {
533 if (dmabuf
->ops
->vunmap
)
534 dmabuf
->ops
->vunmap(dmabuf
, vaddr
);
535 dmabuf
->vmap_ptr
= NULL
;
537 mutex_unlock(&dmabuf
->lock
);
539 EXPORT_SYMBOL_GPL(dma_buf_vunmap
);