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;
66 struct drm_prime_attachment {
68 enum dma_data_direction dir;
71 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle)
73 struct drm_prime_member *member;
75 member = kmalloc(sizeof(*member), GFP_KERNEL);
80 member->dma_buf = dma_buf;
81 member->handle = handle;
82 list_add(&member->entry, &prime_fpriv->head);
86 static int drm_gem_map_attach(struct dma_buf *dma_buf,
87 struct device *target_dev,
88 struct dma_buf_attachment *attach)
90 struct drm_prime_attachment *prime_attach;
91 struct drm_gem_object *obj = dma_buf->priv;
92 struct drm_device *dev = obj->dev;
94 prime_attach = kzalloc(sizeof(*prime_attach), GFP_KERNEL);
98 prime_attach->dir = DMA_NONE;
99 attach->priv = prime_attach;
101 if (!dev->driver->gem_prime_pin)
104 return dev->driver->gem_prime_pin(obj);
107 static void drm_gem_map_detach(struct dma_buf *dma_buf,
108 struct dma_buf_attachment *attach)
110 struct drm_prime_attachment *prime_attach = attach->priv;
111 struct drm_gem_object *obj = dma_buf->priv;
112 struct drm_device *dev = obj->dev;
113 struct sg_table *sgt;
115 if (dev->driver->gem_prime_unpin)
116 dev->driver->gem_prime_unpin(obj);
121 sgt = prime_attach->sgt;
123 if (prime_attach->dir != DMA_NONE)
124 dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
133 static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
134 enum dma_data_direction dir)
136 struct drm_prime_attachment *prime_attach = attach->priv;
137 struct drm_gem_object *obj = attach->dmabuf->priv;
138 struct sg_table *sgt;
140 if (WARN_ON(dir == DMA_NONE || !prime_attach))
141 return ERR_PTR(-EINVAL);
143 /* return the cached mapping when possible */
144 if (prime_attach->dir == dir)
145 return prime_attach->sgt;
148 * two mappings with different directions for the same attachment are
151 if (WARN_ON(prime_attach->dir != DMA_NONE))
152 return ERR_PTR(-EBUSY);
154 mutex_lock(&obj->dev->struct_mutex);
156 sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
159 if (!dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir)) {
162 sgt = ERR_PTR(-ENOMEM);
164 prime_attach->sgt = sgt;
165 prime_attach->dir = dir;
169 mutex_unlock(&obj->dev->struct_mutex);
173 static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
174 struct sg_table *sgt, enum dma_data_direction dir)
176 /* nothing to be done here */
179 static void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
181 struct drm_gem_object *obj = dma_buf->priv;
183 if (obj->export_dma_buf == dma_buf) {
184 /* drop the reference on the export fd holds */
185 obj->export_dma_buf = NULL;
186 drm_gem_object_unreference_unlocked(obj);
190 static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
192 struct drm_gem_object *obj = dma_buf->priv;
193 struct drm_device *dev = obj->dev;
195 return dev->driver->gem_prime_vmap(obj);
198 static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
200 struct drm_gem_object *obj = dma_buf->priv;
201 struct drm_device *dev = obj->dev;
203 dev->driver->gem_prime_vunmap(obj, vaddr);
206 static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
207 unsigned long page_num)
212 static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
213 unsigned long page_num, void *addr)
217 static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
218 unsigned long page_num)
223 static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
224 unsigned long page_num, void *addr)
229 static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
230 struct vm_area_struct *vma)
235 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
236 .attach = drm_gem_map_attach,
237 .detach = drm_gem_map_detach,
238 .map_dma_buf = drm_gem_map_dma_buf,
239 .unmap_dma_buf = drm_gem_unmap_dma_buf,
240 .release = drm_gem_dmabuf_release,
241 .kmap = drm_gem_dmabuf_kmap,
242 .kmap_atomic = drm_gem_dmabuf_kmap_atomic,
243 .kunmap = drm_gem_dmabuf_kunmap,
244 .kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
245 .mmap = drm_gem_dmabuf_mmap,
246 .vmap = drm_gem_dmabuf_vmap,
247 .vunmap = drm_gem_dmabuf_vunmap,
253 * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
254 * simpler APIs by using the helper functions @drm_gem_prime_export and
255 * @drm_gem_prime_import. These functions implement dma-buf support in terms of
256 * five lower-level driver callbacks:
260 * - @gem_prime_pin (optional): prepare a GEM object for exporting
262 * - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
264 * - @gem_prime_vmap: vmap a buffer exported by your driver
266 * - @gem_prime_vunmap: vunmap a buffer exported by your driver
270 * - @gem_prime_import_sg_table (import): produce a GEM object from another
271 * driver's scatter/gather table
274 struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
275 struct drm_gem_object *obj, int flags)
277 return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size, flags);
279 EXPORT_SYMBOL(drm_gem_prime_export);
281 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
282 struct drm_file *file_priv, uint32_t handle, uint32_t flags,
285 struct drm_gem_object *obj;
288 struct dma_buf *dmabuf;
290 obj = drm_gem_object_lookup(dev, file_priv, handle);
294 mutex_lock(&file_priv->prime.lock);
295 /* re-export the original imported object */
296 if (obj->import_attach) {
297 dmabuf = obj->import_attach->dmabuf;
301 if (obj->export_dma_buf) {
302 dmabuf = obj->export_dma_buf;
306 buf = dev->driver->gem_prime_export(dev, obj, flags);
308 /* normally the created dma-buf takes ownership of the ref,
309 * but if that fails then drop the ref
314 obj->export_dma_buf = buf;
316 /* if we've exported this buffer the cheat and add it to the import list
317 * so we get the correct handle back
319 ret = drm_prime_add_buf_handle(&file_priv->prime,
320 obj->export_dma_buf, handle);
322 goto fail_put_dmabuf;
324 *prime_fd = dma_buf_fd(buf, flags);
325 mutex_unlock(&file_priv->prime.lock);
330 *prime_fd = dma_buf_fd(dmabuf, flags);
334 /* clear NOT to be checked when releasing dma_buf */
335 obj->export_dma_buf = NULL;
338 drm_gem_object_unreference_unlocked(obj);
339 mutex_unlock(&file_priv->prime.lock);
342 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
344 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
345 struct dma_buf *dma_buf)
347 struct dma_buf_attachment *attach;
348 struct sg_table *sgt;
349 struct drm_gem_object *obj;
352 if (!dev->driver->gem_prime_import_sg_table)
353 return ERR_PTR(-EINVAL);
355 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
357 if (obj->dev == dev) {
359 * Importing dmabuf exported from out own gem increases
360 * refcount on gem itself instead of f_count of dmabuf.
362 drm_gem_object_reference(obj);
367 attach = dma_buf_attach(dma_buf, dev->dev);
369 return ERR_CAST(attach);
371 get_dma_buf(dma_buf);
373 sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
374 if (IS_ERR_OR_NULL(sgt)) {
379 obj = dev->driver->gem_prime_import_sg_table(dev, dma_buf->size, sgt);
385 obj->import_attach = attach;
390 dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
392 dma_buf_detach(dma_buf, attach);
393 dma_buf_put(dma_buf);
397 EXPORT_SYMBOL(drm_gem_prime_import);
399 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
400 struct drm_file *file_priv, int prime_fd, uint32_t *handle)
402 struct dma_buf *dma_buf;
403 struct drm_gem_object *obj;
406 dma_buf = dma_buf_get(prime_fd);
408 return PTR_ERR(dma_buf);
410 mutex_lock(&file_priv->prime.lock);
412 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
419 /* never seen this one, need to import */
420 obj = dev->driver->gem_prime_import(dev, dma_buf);
426 ret = drm_gem_handle_create(file_priv, obj, handle);
427 drm_gem_object_unreference_unlocked(obj);
431 ret = drm_prime_add_buf_handle(&file_priv->prime,
436 mutex_unlock(&file_priv->prime.lock);
438 dma_buf_put(dma_buf);
443 /* hmm, if driver attached, we are relying on the free-object path
444 * to detach.. which seems ok..
446 drm_gem_object_handle_unreference_unlocked(obj);
448 dma_buf_put(dma_buf);
449 mutex_unlock(&file_priv->prime.lock);
452 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
454 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
455 struct drm_file *file_priv)
457 struct drm_prime_handle *args = data;
460 if (!drm_core_check_feature(dev, DRIVER_PRIME))
463 if (!dev->driver->prime_handle_to_fd)
466 /* check flags are valid */
467 if (args->flags & ~DRM_CLOEXEC)
470 /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
471 flags = args->flags & DRM_CLOEXEC;
473 return dev->driver->prime_handle_to_fd(dev, file_priv,
474 args->handle, flags, &args->fd);
477 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
478 struct drm_file *file_priv)
480 struct drm_prime_handle *args = data;
482 if (!drm_core_check_feature(dev, DRIVER_PRIME))
485 if (!dev->driver->prime_fd_to_handle)
488 return dev->driver->prime_fd_to_handle(dev, file_priv,
489 args->fd, &args->handle);
493 * drm_prime_pages_to_sg
495 * this helper creates an sg table object from a set of pages
496 * the driver is responsible for mapping the pages into the
497 * importers address space
499 struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
501 struct sg_table *sg = NULL;
504 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
510 ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
511 nr_pages << PAGE_SHIFT, GFP_KERNEL);
520 EXPORT_SYMBOL(drm_prime_pages_to_sg);
522 /* export an sg table into an array of pages and addresses
523 this is currently required by the TTM driver in order to do correct fault
525 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
526 dma_addr_t *addrs, int max_pages)
529 struct scatterlist *sg;
536 for_each_sg(sgt->sgl, sg, sgt->nents, count) {
540 addr = sg_dma_address(sg);
543 if (WARN_ON(pg_index >= max_pages))
545 pages[pg_index] = page;
547 addrs[pg_index] = addr;
557 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
558 /* helper function to cleanup a GEM/prime object */
559 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
561 struct dma_buf_attachment *attach;
562 struct dma_buf *dma_buf;
563 attach = obj->import_attach;
565 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
566 dma_buf = attach->dmabuf;
567 dma_buf_detach(attach->dmabuf, attach);
568 /* remove the reference */
569 dma_buf_put(dma_buf);
571 EXPORT_SYMBOL(drm_prime_gem_destroy);
573 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
575 INIT_LIST_HEAD(&prime_fpriv->head);
576 mutex_init(&prime_fpriv->lock);
578 EXPORT_SYMBOL(drm_prime_init_file_private);
580 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
582 /* by now drm_gem_release should've made sure the list is empty */
583 WARN_ON(!list_empty(&prime_fpriv->head));
585 EXPORT_SYMBOL(drm_prime_destroy_file_private);
587 int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle)
589 struct drm_prime_member *member;
591 list_for_each_entry(member, &prime_fpriv->head, entry) {
592 if (member->dma_buf == dma_buf) {
593 *handle = member->handle;
599 EXPORT_SYMBOL(drm_prime_lookup_buf_handle);
601 void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf)
603 struct drm_prime_member *member, *safe;
605 mutex_lock(&prime_fpriv->lock);
606 list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
607 if (member->dma_buf == dma_buf) {
608 dma_buf_put(dma_buf);
609 list_del(&member->entry);
613 mutex_unlock(&prime_fpriv->lock);
615 EXPORT_SYMBOL(drm_prime_remove_buf_handle);