2 * Copyright © 2012 Red Hat
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
24 * Dave Airlie <airlied@redhat.com>
25 * Rob Clark <rob.clark@linaro.org>
29 #include <linux/export.h>
30 #include <linux/dma-buf.h>
34 * DMA-BUF/GEM Object references and lifetime overview:
36 * On the export the dma_buf holds a reference to the exporting GEM
37 * object. It takes this reference in handle_to_fd_ioctl, when it
38 * first calls .prime_export and stores the exporting GEM object in
39 * the dma_buf priv. This reference is released when the dma_buf
40 * object goes away in the driver .release function.
42 * On the import the importing GEM object holds a reference to the
43 * dma_buf (which in turn holds a ref to the exporting GEM object).
44 * It takes that reference in the fd_to_handle ioctl.
45 * It calls dma_buf_get, creates an attachment to it and stores the
46 * attachment in the GEM object. When this attachment is destroyed
47 * when the imported object is destroyed, we remove the attachment
48 * and drop the reference to the dma_buf.
50 * Thus the chain of references always flows in one direction
51 * (avoiding loops): importing_gem -> dmabuf -> exporting_gem
53 * Self-importing: if userspace is using PRIME as a replacement for flink
54 * then it will get a fd->handle request for a GEM object that it created.
55 * Drivers should detect this situation and return back the gem object
56 * from the dma-buf private. Prime will do this automatically for drivers that
57 * use the drm_gem_prime_{import,export} helpers.
60 struct drm_prime_member {
61 struct list_head entry;
62 struct dma_buf *dma_buf;
65 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle);
67 static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
68 enum dma_data_direction dir)
70 struct drm_gem_object *obj = attach->dmabuf->priv;
73 mutex_lock(&obj->dev->struct_mutex);
75 sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
77 if (!IS_ERR_OR_NULL(sgt))
78 dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir);
80 mutex_unlock(&obj->dev->struct_mutex);
84 static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
85 struct sg_table *sgt, enum dma_data_direction dir)
87 dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir);
92 static void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
94 struct drm_gem_object *obj = dma_buf->priv;
95 struct drm_device *dev = obj->dev;
97 if (obj->export_dma_buf == dma_buf) {
98 /* drop the reference on the export fd holds */
99 obj->export_dma_buf = NULL;
100 if (dev->driver->gem_prime_unpin)
101 dev->driver->gem_prime_unpin(obj);
102 drm_gem_object_unreference_unlocked(obj);
106 static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
108 struct drm_gem_object *obj = dma_buf->priv;
109 struct drm_device *dev = obj->dev;
111 return dev->driver->gem_prime_vmap(obj);
114 static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
116 struct drm_gem_object *obj = dma_buf->priv;
117 struct drm_device *dev = obj->dev;
119 dev->driver->gem_prime_vunmap(obj, vaddr);
122 static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
123 unsigned long page_num)
128 static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
129 unsigned long page_num, void *addr)
133 static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
134 unsigned long page_num)
139 static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
140 unsigned long page_num, void *addr)
145 static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
146 struct vm_area_struct *vma)
151 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
152 .map_dma_buf = drm_gem_map_dma_buf,
153 .unmap_dma_buf = drm_gem_unmap_dma_buf,
154 .release = drm_gem_dmabuf_release,
155 .kmap = drm_gem_dmabuf_kmap,
156 .kmap_atomic = drm_gem_dmabuf_kmap_atomic,
157 .kunmap = drm_gem_dmabuf_kunmap,
158 .kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
159 .mmap = drm_gem_dmabuf_mmap,
160 .vmap = drm_gem_dmabuf_vmap,
161 .vunmap = drm_gem_dmabuf_vunmap,
167 * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
168 * simpler APIs by using the helper functions @drm_gem_prime_export and
169 * @drm_gem_prime_import. These functions implement dma-buf support in terms of
170 * five lower-level driver callbacks:
174 * - @gem_prime_pin (optional): prepare a GEM object for exporting
176 * - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
178 * - @gem_prime_vmap: vmap a buffer exported by your driver
180 * - @gem_prime_vunmap: vunmap a buffer exported by your driver
184 * - @gem_prime_import_sg_table (import): produce a GEM object from another
185 * driver's scatter/gather table
188 struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
189 struct drm_gem_object *obj, int flags)
193 if (dev->driver->gem_prime_pin) {
194 int ret = dev->driver->gem_prime_pin(obj);
198 buf = dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size, flags);
200 if (IS_ERR(buf) && dev->driver->gem_prime_unpin)
201 dev->driver->gem_prime_unpin(obj);
204 EXPORT_SYMBOL(drm_gem_prime_export);
206 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
207 struct drm_file *file_priv, uint32_t handle, uint32_t flags,
210 struct drm_gem_object *obj;
213 struct dma_buf *dmabuf;
215 obj = drm_gem_object_lookup(dev, file_priv, handle);
219 mutex_lock(&file_priv->prime.lock);
220 /* re-export the original imported object */
221 if (obj->import_attach) {
222 dmabuf = obj->import_attach->dmabuf;
226 if (obj->export_dma_buf) {
227 dmabuf = obj->export_dma_buf;
231 buf = dev->driver->gem_prime_export(dev, obj, flags);
233 /* normally the created dma-buf takes ownership of the ref,
234 * but if that fails then drop the ref
239 obj->export_dma_buf = buf;
241 /* if we've exported this buffer the cheat and add it to the import list
242 * so we get the correct handle back
244 ret = drm_prime_add_buf_handle(&file_priv->prime,
245 obj->export_dma_buf, handle);
249 *prime_fd = dma_buf_fd(buf, flags);
250 mutex_unlock(&file_priv->prime.lock);
255 *prime_fd = dma_buf_fd(dmabuf, flags);
257 drm_gem_object_unreference_unlocked(obj);
258 mutex_unlock(&file_priv->prime.lock);
261 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
263 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
264 struct dma_buf *dma_buf)
266 struct dma_buf_attachment *attach;
267 struct sg_table *sgt;
268 struct drm_gem_object *obj;
271 if (!dev->driver->gem_prime_import_sg_table)
272 return ERR_PTR(-EINVAL);
274 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
276 if (obj->dev == dev) {
278 * Importing dmabuf exported from out own gem increases
279 * refcount on gem itself instead of f_count of dmabuf.
281 drm_gem_object_reference(obj);
286 attach = dma_buf_attach(dma_buf, dev->dev);
288 return ERR_PTR(PTR_ERR(attach));
290 get_dma_buf(dma_buf);
292 sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
293 if (IS_ERR_OR_NULL(sgt)) {
298 obj = dev->driver->gem_prime_import_sg_table(dev, dma_buf->size, sgt);
304 obj->import_attach = attach;
309 dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
311 dma_buf_detach(dma_buf, attach);
312 dma_buf_put(dma_buf);
316 EXPORT_SYMBOL(drm_gem_prime_import);
318 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
319 struct drm_file *file_priv, int prime_fd, uint32_t *handle)
321 struct dma_buf *dma_buf;
322 struct drm_gem_object *obj;
325 dma_buf = dma_buf_get(prime_fd);
327 return PTR_ERR(dma_buf);
329 mutex_lock(&file_priv->prime.lock);
331 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
338 /* never seen this one, need to import */
339 obj = dev->driver->gem_prime_import(dev, dma_buf);
345 ret = drm_gem_handle_create(file_priv, obj, handle);
346 drm_gem_object_unreference_unlocked(obj);
350 ret = drm_prime_add_buf_handle(&file_priv->prime,
355 mutex_unlock(&file_priv->prime.lock);
357 dma_buf_put(dma_buf);
362 /* hmm, if driver attached, we are relying on the free-object path
363 * to detach.. which seems ok..
365 drm_gem_object_handle_unreference_unlocked(obj);
367 dma_buf_put(dma_buf);
368 mutex_unlock(&file_priv->prime.lock);
371 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
373 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
374 struct drm_file *file_priv)
376 struct drm_prime_handle *args = data;
379 if (!drm_core_check_feature(dev, DRIVER_PRIME))
382 if (!dev->driver->prime_handle_to_fd)
385 /* check flags are valid */
386 if (args->flags & ~DRM_CLOEXEC)
389 /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
390 flags = args->flags & DRM_CLOEXEC;
392 return dev->driver->prime_handle_to_fd(dev, file_priv,
393 args->handle, flags, &args->fd);
396 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
397 struct drm_file *file_priv)
399 struct drm_prime_handle *args = data;
401 if (!drm_core_check_feature(dev, DRIVER_PRIME))
404 if (!dev->driver->prime_fd_to_handle)
407 return dev->driver->prime_fd_to_handle(dev, file_priv,
408 args->fd, &args->handle);
412 * drm_prime_pages_to_sg
414 * this helper creates an sg table object from a set of pages
415 * the driver is responsible for mapping the pages into the
416 * importers address space
418 struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
420 struct sg_table *sg = NULL;
423 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
427 ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
428 nr_pages << PAGE_SHIFT, GFP_KERNEL);
437 EXPORT_SYMBOL(drm_prime_pages_to_sg);
439 /* export an sg table into an array of pages and addresses
440 this is currently required by the TTM driver in order to do correct fault
442 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
443 dma_addr_t *addrs, int max_pages)
446 struct scatterlist *sg;
453 for_each_sg(sgt->sgl, sg, sgt->nents, count) {
457 addr = sg_dma_address(sg);
460 if (WARN_ON(pg_index >= max_pages))
462 pages[pg_index] = page;
464 addrs[pg_index] = addr;
474 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
475 /* helper function to cleanup a GEM/prime object */
476 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
478 struct dma_buf_attachment *attach;
479 struct dma_buf *dma_buf;
480 attach = obj->import_attach;
482 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
483 dma_buf = attach->dmabuf;
484 dma_buf_detach(attach->dmabuf, attach);
485 /* remove the reference */
486 dma_buf_put(dma_buf);
488 EXPORT_SYMBOL(drm_prime_gem_destroy);
490 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
492 INIT_LIST_HEAD(&prime_fpriv->head);
493 mutex_init(&prime_fpriv->lock);
495 EXPORT_SYMBOL(drm_prime_init_file_private);
497 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
499 /* by now drm_gem_release should've made sure the list is empty */
500 WARN_ON(!list_empty(&prime_fpriv->head));
502 EXPORT_SYMBOL(drm_prime_destroy_file_private);
504 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle)
506 struct drm_prime_member *member;
508 member = kmalloc(sizeof(*member), GFP_KERNEL);
512 get_dma_buf(dma_buf);
513 member->dma_buf = dma_buf;
514 member->handle = handle;
515 list_add(&member->entry, &prime_fpriv->head);
519 int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle)
521 struct drm_prime_member *member;
523 list_for_each_entry(member, &prime_fpriv->head, entry) {
524 if (member->dma_buf == dma_buf) {
525 *handle = member->handle;
531 EXPORT_SYMBOL(drm_prime_lookup_buf_handle);
533 void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf)
535 struct drm_prime_member *member, *safe;
537 mutex_lock(&prime_fpriv->lock);
538 list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
539 if (member->dma_buf == dma_buf) {
540 dma_buf_put(dma_buf);
541 list_del(&member->entry);
545 mutex_unlock(&prime_fpriv->lock);
547 EXPORT_SYMBOL(drm_prime_remove_buf_handle);