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>
30 #include <linux/debugfs.h>
31 #include <linux/seq_file.h>
33 static inline int is_dma_buf_file(struct file *);
36 struct list_head head;
40 static struct dma_buf_list db_list;
42 static int dma_buf_release(struct inode *inode, struct file *file)
44 struct dma_buf *dmabuf;
46 if (!is_dma_buf_file(file))
49 dmabuf = file->private_data;
51 BUG_ON(dmabuf->vmapping_counter);
53 dmabuf->ops->release(dmabuf);
55 mutex_lock(&db_list.lock);
56 list_del(&dmabuf->list_node);
57 mutex_unlock(&db_list.lock);
63 static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
65 struct dma_buf *dmabuf;
67 if (!is_dma_buf_file(file))
70 dmabuf = file->private_data;
72 /* check for overflowing the buffer's size */
73 if (vma->vm_pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
74 dmabuf->size >> PAGE_SHIFT)
77 return dmabuf->ops->mmap(dmabuf, vma);
80 static const struct file_operations dma_buf_fops = {
81 .release = dma_buf_release,
82 .mmap = dma_buf_mmap_internal,
86 * is_dma_buf_file - Check if struct file* is associated with dma_buf
88 static inline int is_dma_buf_file(struct file *file)
90 return file->f_op == &dma_buf_fops;
93 #ifdef CONFIG_ARCH_ROCKCHIP
94 int dma_buf_is_dma_buf(struct file *file)
96 return is_dma_buf_file(file);
101 * dma_buf_export_named - Creates a new dma_buf, and associates an anon file
102 * with this buffer, so it can be exported.
103 * Also connect the allocator specific data and ops to the buffer.
104 * Additionally, provide a name string for exporter; useful in debugging.
106 * @priv: [in] Attach private data of allocator to this buffer
107 * @ops: [in] Attach allocator-defined dma buf ops to the new buffer.
108 * @size: [in] Size of the buffer
109 * @flags: [in] mode flags for the file.
110 * @exp_name: [in] name of the exporting module - useful for debugging.
112 * Returns, on success, a newly created dma_buf object, which wraps the
113 * supplied private data and operations for dma_buf_ops. On either missing
114 * ops, or error in allocating struct dma_buf, will return negative error.
117 struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
118 size_t size, int flags, const char *exp_name)
120 struct dma_buf *dmabuf;
123 if (WARN_ON(!priv || !ops
125 || !ops->unmap_dma_buf
130 return ERR_PTR(-EINVAL);
133 dmabuf = kzalloc(sizeof(struct dma_buf), GFP_KERNEL);
135 return ERR_PTR(-ENOMEM);
140 dmabuf->exp_name = exp_name;
142 file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, flags);
146 mutex_init(&dmabuf->lock);
147 INIT_LIST_HEAD(&dmabuf->attachments);
149 mutex_lock(&db_list.lock);
150 list_add(&dmabuf->list_node, &db_list.head);
151 mutex_unlock(&db_list.lock);
155 EXPORT_SYMBOL_GPL(dma_buf_export_named);
159 * dma_buf_fd - returns a file descriptor for the given dma_buf
160 * @dmabuf: [in] pointer to dma_buf for which fd is required.
161 * @flags: [in] flags to give to fd
163 * On success, returns an associated 'fd'. Else, returns error.
165 int dma_buf_fd(struct dma_buf *dmabuf, int flags)
169 if (!dmabuf || !dmabuf->file)
172 fd = get_unused_fd_flags(flags);
176 fd_install(fd, dmabuf->file);
180 EXPORT_SYMBOL_GPL(dma_buf_fd);
183 * dma_buf_get - returns the dma_buf structure related to an fd
184 * @fd: [in] fd associated with the dma_buf to be returned
186 * On success, returns the dma_buf structure associated with an fd; uses
187 * file's refcounting done by fget to increase refcount. returns ERR_PTR
190 struct dma_buf *dma_buf_get(int fd)
197 return ERR_PTR(-EBADF);
199 if (!is_dma_buf_file(file)) {
201 return ERR_PTR(-EINVAL);
204 return file->private_data;
206 EXPORT_SYMBOL_GPL(dma_buf_get);
209 * dma_buf_put - decreases refcount of the buffer
210 * @dmabuf: [in] buffer to reduce refcount of
212 * Uses file's refcounting done implicitly by fput()
214 void dma_buf_put(struct dma_buf *dmabuf)
216 if (WARN_ON(!dmabuf || !dmabuf->file))
221 EXPORT_SYMBOL_GPL(dma_buf_put);
224 * dma_buf_attach - Add the device to dma_buf's attachments list; optionally,
225 * calls attach() of dma_buf_ops to allow device-specific attach functionality
226 * @dmabuf: [in] buffer to attach device to.
227 * @dev: [in] device to be attached.
229 * Returns struct dma_buf_attachment * for this attachment; may return negative
233 struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
236 struct dma_buf_attachment *attach;
239 if (WARN_ON(!dmabuf || !dev))
240 return ERR_PTR(-EINVAL);
242 attach = kzalloc(sizeof(struct dma_buf_attachment), GFP_KERNEL);
244 return ERR_PTR(-ENOMEM);
247 attach->dmabuf = dmabuf;
249 mutex_lock(&dmabuf->lock);
251 if (dmabuf->ops->attach) {
252 ret = dmabuf->ops->attach(dmabuf, dev, attach);
256 list_add(&attach->node, &dmabuf->attachments);
258 mutex_unlock(&dmabuf->lock);
263 mutex_unlock(&dmabuf->lock);
266 EXPORT_SYMBOL_GPL(dma_buf_attach);
269 * dma_buf_detach - Remove the given attachment from dmabuf's attachments list;
270 * optionally calls detach() of dma_buf_ops for device-specific detach
271 * @dmabuf: [in] buffer to detach from.
272 * @attach: [in] attachment to be detached; is free'd after this call.
275 void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
277 if (WARN_ON(!dmabuf || !attach))
280 mutex_lock(&dmabuf->lock);
281 list_del(&attach->node);
282 if (dmabuf->ops->detach)
283 dmabuf->ops->detach(dmabuf, attach);
285 mutex_unlock(&dmabuf->lock);
288 EXPORT_SYMBOL_GPL(dma_buf_detach);
291 * dma_buf_map_attachment - Returns the scatterlist table of the attachment;
292 * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
294 * @attach: [in] attachment whose scatterlist is to be returned
295 * @direction: [in] direction of DMA transfer
297 * Returns sg_table containing the scatterlist to be returned; may return NULL
301 struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
302 enum dma_data_direction direction)
304 struct sg_table *sg_table = ERR_PTR(-EINVAL);
308 if (WARN_ON(!attach || !attach->dmabuf))
309 return ERR_PTR(-EINVAL);
311 sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
315 EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
318 * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
319 * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
321 * @attach: [in] attachment to unmap buffer from
322 * @sg_table: [in] scatterlist info of the buffer to unmap
323 * @direction: [in] direction of DMA transfer
326 void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
327 struct sg_table *sg_table,
328 enum dma_data_direction direction)
332 if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
335 attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,
338 EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
342 * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
343 * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific
344 * preparations. Coherency is only guaranteed in the specified range for the
345 * specified access direction.
346 * @dmabuf: [in] buffer to prepare cpu access for.
347 * @start: [in] start of range for cpu access.
348 * @len: [in] length of range for cpu access.
349 * @direction: [in] length of range for cpu access.
351 * Can return negative error values, returns 0 on success.
353 int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len,
354 enum dma_data_direction direction)
358 if (WARN_ON(!dmabuf))
361 if (dmabuf->ops->begin_cpu_access)
362 ret = dmabuf->ops->begin_cpu_access(dmabuf, start, len, direction);
366 EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access);
369 * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the
370 * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific
371 * actions. Coherency is only guaranteed in the specified range for the
372 * specified access direction.
373 * @dmabuf: [in] buffer to complete cpu access for.
374 * @start: [in] start of range for cpu access.
375 * @len: [in] length of range for cpu access.
376 * @direction: [in] length of range for cpu access.
378 * This call must always succeed.
380 void dma_buf_end_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len,
381 enum dma_data_direction direction)
385 if (dmabuf->ops->end_cpu_access)
386 dmabuf->ops->end_cpu_access(dmabuf, start, len, direction);
388 EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access);
391 * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address
392 * space. The same restrictions as for kmap_atomic and friends apply.
393 * @dmabuf: [in] buffer to map page from.
394 * @page_num: [in] page in PAGE_SIZE units to map.
396 * This call must always succeed, any necessary preparations that might fail
397 * need to be done in begin_cpu_access.
399 void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num)
403 return dmabuf->ops->kmap_atomic(dmabuf, page_num);
405 EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic);
408 * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic.
409 * @dmabuf: [in] buffer to unmap page from.
410 * @page_num: [in] page in PAGE_SIZE units to unmap.
411 * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap_atomic.
413 * This call must always succeed.
415 void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, unsigned long page_num,
420 if (dmabuf->ops->kunmap_atomic)
421 dmabuf->ops->kunmap_atomic(dmabuf, page_num, vaddr);
423 EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic);
426 * dma_buf_kmap - Map a page of the buffer object into kernel address space. The
427 * same restrictions as for kmap and friends apply.
428 * @dmabuf: [in] buffer to map page from.
429 * @page_num: [in] page in PAGE_SIZE units to map.
431 * This call must always succeed, any necessary preparations that might fail
432 * need to be done in begin_cpu_access.
434 void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num)
438 return dmabuf->ops->kmap(dmabuf, page_num);
440 EXPORT_SYMBOL_GPL(dma_buf_kmap);
443 * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap.
444 * @dmabuf: [in] buffer to unmap page from.
445 * @page_num: [in] page in PAGE_SIZE units to unmap.
446 * @vaddr: [in] kernel space pointer obtained from dma_buf_kmap.
448 * This call must always succeed.
450 void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num,
455 if (dmabuf->ops->kunmap)
456 dmabuf->ops->kunmap(dmabuf, page_num, vaddr);
458 EXPORT_SYMBOL_GPL(dma_buf_kunmap);
462 * dma_buf_mmap - Setup up a userspace mmap with the given vma
463 * @dmabuf: [in] buffer that should back the vma
464 * @vma: [in] vma for the mmap
465 * @pgoff: [in] offset in pages where this mmap should start within the
468 * This function adjusts the passed in vma so that it points at the file of the
469 * dma_buf operation. It alsog adjusts the starting pgoff and does bounds
470 * checking on the size of the vma. Then it calls the exporters mmap function to
471 * set up the mapping.
473 * Can return negative error values, returns 0 on success.
475 int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
478 struct file *oldfile;
481 if (WARN_ON(!dmabuf || !vma))
484 /* check for offset overflow */
485 if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) < pgoff)
488 /* check for overflowing the buffer's size */
489 if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
490 dmabuf->size >> PAGE_SHIFT)
493 /* readjust the vma */
494 get_file(dmabuf->file);
495 oldfile = vma->vm_file;
496 vma->vm_file = dmabuf->file;
497 vma->vm_pgoff = pgoff;
499 ret = dmabuf->ops->mmap(dmabuf, vma);
501 /* restore old parameters on failure */
502 vma->vm_file = oldfile;
511 EXPORT_SYMBOL_GPL(dma_buf_mmap);
514 * dma_buf_vmap - Create virtual mapping for the buffer object into kernel
515 * address space. Same restrictions as for vmap and friends apply.
516 * @dmabuf: [in] buffer to vmap
518 * This call may fail due to lack of virtual mapping address space.
519 * These calls are optional in drivers. The intended use for them
520 * is for mapping objects linear in kernel space for high use objects.
521 * Please attempt to use kmap/kunmap before thinking about these interfaces.
523 void *dma_buf_vmap(struct dma_buf *dmabuf)
527 if (WARN_ON(!dmabuf))
530 if (!dmabuf->ops->vmap)
533 mutex_lock(&dmabuf->lock);
534 if (dmabuf->vmapping_counter) {
535 dmabuf->vmapping_counter++;
536 BUG_ON(!dmabuf->vmap_ptr);
537 ptr = dmabuf->vmap_ptr;
541 BUG_ON(dmabuf->vmap_ptr);
543 ptr = dmabuf->ops->vmap(dmabuf);
544 if (IS_ERR_OR_NULL(ptr))
547 dmabuf->vmap_ptr = ptr;
548 dmabuf->vmapping_counter = 1;
551 mutex_unlock(&dmabuf->lock);
554 EXPORT_SYMBOL_GPL(dma_buf_vmap);
557 * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
558 * @dmabuf: [in] buffer to vunmap
559 * @vaddr: [in] vmap to vunmap
561 void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
563 if (WARN_ON(!dmabuf))
566 BUG_ON(!dmabuf->vmap_ptr);
567 BUG_ON(dmabuf->vmapping_counter == 0);
568 BUG_ON(dmabuf->vmap_ptr != vaddr);
570 mutex_lock(&dmabuf->lock);
571 if (--dmabuf->vmapping_counter == 0) {
572 if (dmabuf->ops->vunmap)
573 dmabuf->ops->vunmap(dmabuf, vaddr);
574 dmabuf->vmap_ptr = NULL;
576 mutex_unlock(&dmabuf->lock);
578 EXPORT_SYMBOL_GPL(dma_buf_vunmap);
580 #ifdef CONFIG_DEBUG_FS
581 static int dma_buf_describe(struct seq_file *s)
584 struct dma_buf *buf_obj;
585 struct dma_buf_attachment *attach_obj;
586 int count = 0, attach_count;
589 ret = mutex_lock_interruptible(&db_list.lock);
594 seq_printf(s, "\nDma-buf Objects:\n");
595 seq_printf(s, "\texp_name\tsize\tflags\tmode\tcount\n");
597 list_for_each_entry(buf_obj, &db_list.head, list_node) {
598 ret = mutex_lock_interruptible(&buf_obj->lock);
602 "\tERROR locking buffer object: skipping\n");
608 seq_printf(s, "\t%s\t%08zu\t%08x\t%08x\t%08ld\n",
609 buf_obj->exp_name, buf_obj->size,
610 buf_obj->file->f_flags, buf_obj->file->f_mode,
611 (long)(buf_obj->file->f_count.counter));
613 seq_printf(s, "\t\tAttached Devices:\n");
616 list_for_each_entry(attach_obj, &buf_obj->attachments, node) {
617 seq_printf(s, "\t\t");
619 seq_printf(s, "%s\n", attach_obj->dev->init_name);
623 seq_printf(s, "\n\t\tTotal %d devices attached\n",
627 size += buf_obj->size;
628 mutex_unlock(&buf_obj->lock);
631 seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size);
633 mutex_unlock(&db_list.lock);
637 static int dma_buf_show(struct seq_file *s, void *unused)
639 void (*func)(struct seq_file *) = s->private;
644 static int dma_buf_debug_open(struct inode *inode, struct file *file)
646 return single_open(file, dma_buf_show, inode->i_private);
649 static const struct file_operations dma_buf_debug_fops = {
650 .open = dma_buf_debug_open,
653 .release = single_release,
656 static struct dentry *dma_buf_debugfs_dir;
658 static int dma_buf_init_debugfs(void)
661 dma_buf_debugfs_dir = debugfs_create_dir("dma_buf", NULL);
662 if (IS_ERR(dma_buf_debugfs_dir)) {
663 err = PTR_ERR(dma_buf_debugfs_dir);
664 dma_buf_debugfs_dir = NULL;
668 err = dma_buf_debugfs_create_file("bufinfo", dma_buf_describe);
671 pr_debug("dma_buf: debugfs: failed to create node bufinfo\n");
676 static void dma_buf_uninit_debugfs(void)
678 if (dma_buf_debugfs_dir)
679 debugfs_remove_recursive(dma_buf_debugfs_dir);
682 int dma_buf_debugfs_create_file(const char *name,
683 int (*write)(struct seq_file *))
687 d = debugfs_create_file(name, S_IRUGO, dma_buf_debugfs_dir,
688 write, &dma_buf_debug_fops);
696 static inline int dma_buf_init_debugfs(void)
700 static inline void dma_buf_uninit_debugfs(void)
705 static int __init dma_buf_init(void)
707 mutex_init(&db_list.lock);
708 INIT_LIST_HEAD(&db_list.head);
709 dma_buf_init_debugfs();
712 subsys_initcall(dma_buf_init);
714 static void __exit dma_buf_deinit(void)
716 dma_buf_uninit_debugfs();
718 __exitcall(dma_buf_deinit);