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 int drm_gem_map_attach(struct dma_buf *dma_buf,
68 struct device *target_dev,
69 struct dma_buf_attachment *attach)
71 struct drm_gem_object *obj = dma_buf->priv;
72 struct drm_device *dev = obj->dev;
74 if (!dev->driver->gem_prime_pin)
77 return dev->driver->gem_prime_pin(obj);
80 static void drm_gem_map_detach(struct dma_buf *dma_buf,
81 struct dma_buf_attachment *attach)
83 struct drm_gem_object *obj = dma_buf->priv;
84 struct drm_device *dev = obj->dev;
86 if (dev->driver->gem_prime_unpin)
87 dev->driver->gem_prime_unpin(obj);
90 static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
91 enum dma_data_direction dir)
93 struct drm_gem_object *obj = attach->dmabuf->priv;
96 mutex_lock(&obj->dev->struct_mutex);
98 sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
100 if (!IS_ERR_OR_NULL(sgt))
101 dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir);
103 mutex_unlock(&obj->dev->struct_mutex);
107 static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
108 struct sg_table *sgt, enum dma_data_direction dir)
110 dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir);
115 static void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
117 struct drm_gem_object *obj = dma_buf->priv;
119 if (obj->export_dma_buf == dma_buf) {
120 /* drop the reference on the export fd holds */
121 obj->export_dma_buf = NULL;
122 drm_gem_object_unreference_unlocked(obj);
126 static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
128 struct drm_gem_object *obj = dma_buf->priv;
129 struct drm_device *dev = obj->dev;
131 return dev->driver->gem_prime_vmap(obj);
134 static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
136 struct drm_gem_object *obj = dma_buf->priv;
137 struct drm_device *dev = obj->dev;
139 dev->driver->gem_prime_vunmap(obj, vaddr);
142 static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
143 unsigned long page_num)
148 static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
149 unsigned long page_num, void *addr)
153 static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
154 unsigned long page_num)
159 static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
160 unsigned long page_num, void *addr)
165 static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
166 struct vm_area_struct *vma)
171 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
172 .attach = drm_gem_map_attach,
173 .detach = drm_gem_map_detach,
174 .map_dma_buf = drm_gem_map_dma_buf,
175 .unmap_dma_buf = drm_gem_unmap_dma_buf,
176 .release = drm_gem_dmabuf_release,
177 .kmap = drm_gem_dmabuf_kmap,
178 .kmap_atomic = drm_gem_dmabuf_kmap_atomic,
179 .kunmap = drm_gem_dmabuf_kunmap,
180 .kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
181 .mmap = drm_gem_dmabuf_mmap,
182 .vmap = drm_gem_dmabuf_vmap,
183 .vunmap = drm_gem_dmabuf_vunmap,
189 * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
190 * simpler APIs by using the helper functions @drm_gem_prime_export and
191 * @drm_gem_prime_import. These functions implement dma-buf support in terms of
192 * five lower-level driver callbacks:
196 * - @gem_prime_pin (optional): prepare a GEM object for exporting
198 * - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
200 * - @gem_prime_vmap: vmap a buffer exported by your driver
202 * - @gem_prime_vunmap: vunmap a buffer exported by your driver
206 * - @gem_prime_import_sg_table (import): produce a GEM object from another
207 * driver's scatter/gather table
210 struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
211 struct drm_gem_object *obj, int flags)
213 return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size, flags);
215 EXPORT_SYMBOL(drm_gem_prime_export);
217 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
218 struct drm_file *file_priv, uint32_t handle, uint32_t flags,
221 struct drm_gem_object *obj;
224 struct dma_buf *dmabuf;
226 obj = drm_gem_object_lookup(dev, file_priv, handle);
230 mutex_lock(&file_priv->prime.lock);
231 /* re-export the original imported object */
232 if (obj->import_attach) {
233 dmabuf = obj->import_attach->dmabuf;
237 if (obj->export_dma_buf) {
238 dmabuf = obj->export_dma_buf;
242 buf = dev->driver->gem_prime_export(dev, obj, flags);
244 /* normally the created dma-buf takes ownership of the ref,
245 * but if that fails then drop the ref
250 obj->export_dma_buf = buf;
252 /* if we've exported this buffer the cheat and add it to the import list
253 * so we get the correct handle back
255 ret = drm_prime_add_buf_handle(&file_priv->prime,
256 obj->export_dma_buf, handle);
260 *prime_fd = dma_buf_fd(buf, flags);
261 mutex_unlock(&file_priv->prime.lock);
266 *prime_fd = dma_buf_fd(dmabuf, flags);
268 drm_gem_object_unreference_unlocked(obj);
269 mutex_unlock(&file_priv->prime.lock);
272 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
274 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
275 struct dma_buf *dma_buf)
277 struct dma_buf_attachment *attach;
278 struct sg_table *sgt;
279 struct drm_gem_object *obj;
282 if (!dev->driver->gem_prime_import_sg_table)
283 return ERR_PTR(-EINVAL);
285 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
287 if (obj->dev == dev) {
289 * Importing dmabuf exported from out own gem increases
290 * refcount on gem itself instead of f_count of dmabuf.
292 drm_gem_object_reference(obj);
297 attach = dma_buf_attach(dma_buf, dev->dev);
299 return ERR_PTR(PTR_ERR(attach));
301 get_dma_buf(dma_buf);
303 sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
304 if (IS_ERR_OR_NULL(sgt)) {
309 obj = dev->driver->gem_prime_import_sg_table(dev, dma_buf->size, sgt);
315 obj->import_attach = attach;
320 dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
322 dma_buf_detach(dma_buf, attach);
323 dma_buf_put(dma_buf);
327 EXPORT_SYMBOL(drm_gem_prime_import);
329 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
330 struct drm_file *file_priv, int prime_fd, uint32_t *handle)
332 struct dma_buf *dma_buf;
333 struct drm_gem_object *obj;
336 dma_buf = dma_buf_get(prime_fd);
338 return PTR_ERR(dma_buf);
340 mutex_lock(&file_priv->prime.lock);
342 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
349 /* never seen this one, need to import */
350 obj = dev->driver->gem_prime_import(dev, dma_buf);
356 ret = drm_gem_handle_create(file_priv, obj, handle);
357 drm_gem_object_unreference_unlocked(obj);
361 ret = drm_prime_add_buf_handle(&file_priv->prime,
366 mutex_unlock(&file_priv->prime.lock);
368 dma_buf_put(dma_buf);
373 /* hmm, if driver attached, we are relying on the free-object path
374 * to detach.. which seems ok..
376 drm_gem_object_handle_unreference_unlocked(obj);
378 dma_buf_put(dma_buf);
379 mutex_unlock(&file_priv->prime.lock);
382 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
384 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
385 struct drm_file *file_priv)
387 struct drm_prime_handle *args = data;
390 if (!drm_core_check_feature(dev, DRIVER_PRIME))
393 if (!dev->driver->prime_handle_to_fd)
396 /* check flags are valid */
397 if (args->flags & ~DRM_CLOEXEC)
400 /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
401 flags = args->flags & DRM_CLOEXEC;
403 return dev->driver->prime_handle_to_fd(dev, file_priv,
404 args->handle, flags, &args->fd);
407 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
408 struct drm_file *file_priv)
410 struct drm_prime_handle *args = data;
412 if (!drm_core_check_feature(dev, DRIVER_PRIME))
415 if (!dev->driver->prime_fd_to_handle)
418 return dev->driver->prime_fd_to_handle(dev, file_priv,
419 args->fd, &args->handle);
423 * drm_prime_pages_to_sg
425 * this helper creates an sg table object from a set of pages
426 * the driver is responsible for mapping the pages into the
427 * importers address space
429 struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
431 struct sg_table *sg = NULL;
434 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
438 ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
439 nr_pages << PAGE_SHIFT, GFP_KERNEL);
448 EXPORT_SYMBOL(drm_prime_pages_to_sg);
450 /* export an sg table into an array of pages and addresses
451 this is currently required by the TTM driver in order to do correct fault
453 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
454 dma_addr_t *addrs, int max_pages)
457 struct scatterlist *sg;
464 for_each_sg(sgt->sgl, sg, sgt->nents, count) {
468 addr = sg_dma_address(sg);
471 if (WARN_ON(pg_index >= max_pages))
473 pages[pg_index] = page;
475 addrs[pg_index] = addr;
485 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
486 /* helper function to cleanup a GEM/prime object */
487 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
489 struct dma_buf_attachment *attach;
490 struct dma_buf *dma_buf;
491 attach = obj->import_attach;
493 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
494 dma_buf = attach->dmabuf;
495 dma_buf_detach(attach->dmabuf, attach);
496 /* remove the reference */
497 dma_buf_put(dma_buf);
499 EXPORT_SYMBOL(drm_prime_gem_destroy);
501 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
503 INIT_LIST_HEAD(&prime_fpriv->head);
504 mutex_init(&prime_fpriv->lock);
506 EXPORT_SYMBOL(drm_prime_init_file_private);
508 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
510 /* by now drm_gem_release should've made sure the list is empty */
511 WARN_ON(!list_empty(&prime_fpriv->head));
513 EXPORT_SYMBOL(drm_prime_destroy_file_private);
515 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle)
517 struct drm_prime_member *member;
519 member = kmalloc(sizeof(*member), GFP_KERNEL);
523 get_dma_buf(dma_buf);
524 member->dma_buf = dma_buf;
525 member->handle = handle;
526 list_add(&member->entry, &prime_fpriv->head);
530 int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle)
532 struct drm_prime_member *member;
534 list_for_each_entry(member, &prime_fpriv->head, entry) {
535 if (member->dma_buf == dma_buf) {
536 *handle = member->handle;
542 EXPORT_SYMBOL(drm_prime_lookup_buf_handle);
544 void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf)
546 struct drm_prime_member *member, *safe;
548 mutex_lock(&prime_fpriv->lock);
549 list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
550 if (member->dma_buf == dma_buf) {
551 dma_buf_put(dma_buf);
552 list_del(&member->entry);
556 mutex_unlock(&prime_fpriv->lock);
558 EXPORT_SYMBOL(drm_prime_remove_buf_handle);