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;
96 if (obj->export_dma_buf == dma_buf) {
97 /* drop the reference on the export fd holds */
98 obj->export_dma_buf = NULL;
99 drm_gem_object_unreference_unlocked(obj);
103 static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
105 struct drm_gem_object *obj = dma_buf->priv;
106 struct drm_device *dev = obj->dev;
108 return dev->driver->gem_prime_vmap(obj);
111 static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
113 struct drm_gem_object *obj = dma_buf->priv;
114 struct drm_device *dev = obj->dev;
116 dev->driver->gem_prime_vunmap(obj, vaddr);
119 static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
120 unsigned long page_num)
125 static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
126 unsigned long page_num, void *addr)
130 static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
131 unsigned long page_num)
136 static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
137 unsigned long page_num, void *addr)
142 static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
143 struct vm_area_struct *vma)
148 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
149 .map_dma_buf = drm_gem_map_dma_buf,
150 .unmap_dma_buf = drm_gem_unmap_dma_buf,
151 .release = drm_gem_dmabuf_release,
152 .kmap = drm_gem_dmabuf_kmap,
153 .kmap_atomic = drm_gem_dmabuf_kmap_atomic,
154 .kunmap = drm_gem_dmabuf_kunmap,
155 .kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
156 .mmap = drm_gem_dmabuf_mmap,
157 .vmap = drm_gem_dmabuf_vmap,
158 .vunmap = drm_gem_dmabuf_vunmap,
164 * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
165 * simpler APIs by using the helper functions @drm_gem_prime_export and
166 * @drm_gem_prime_import. These functions implement dma-buf support in terms of
167 * five lower-level driver callbacks:
171 * - @gem_prime_pin (optional): prepare a GEM object for exporting
173 * - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
175 * - @gem_prime_vmap: vmap a buffer exported by your driver
177 * - @gem_prime_vunmap: vunmap a buffer exported by your driver
181 * - @gem_prime_import_sg_table (import): produce a GEM object from another
182 * driver's scatter/gather table
185 struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
186 struct drm_gem_object *obj, int flags)
188 if (dev->driver->gem_prime_pin) {
189 int ret = dev->driver->gem_prime_pin(obj);
193 return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size,
196 EXPORT_SYMBOL(drm_gem_prime_export);
198 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
199 struct drm_file *file_priv, uint32_t handle, uint32_t flags,
202 struct drm_gem_object *obj;
205 struct dma_buf *dmabuf;
207 obj = drm_gem_object_lookup(dev, file_priv, handle);
211 mutex_lock(&file_priv->prime.lock);
212 /* re-export the original imported object */
213 if (obj->import_attach) {
214 dmabuf = obj->import_attach->dmabuf;
218 if (obj->export_dma_buf) {
219 dmabuf = obj->export_dma_buf;
223 buf = dev->driver->gem_prime_export(dev, obj, flags);
225 /* normally the created dma-buf takes ownership of the ref,
226 * but if that fails then drop the ref
231 obj->export_dma_buf = buf;
233 /* if we've exported this buffer the cheat and add it to the import list
234 * so we get the correct handle back
236 ret = drm_prime_add_buf_handle(&file_priv->prime,
237 obj->export_dma_buf, handle);
241 *prime_fd = dma_buf_fd(buf, flags);
242 mutex_unlock(&file_priv->prime.lock);
247 *prime_fd = dma_buf_fd(dmabuf, flags);
249 drm_gem_object_unreference_unlocked(obj);
250 mutex_unlock(&file_priv->prime.lock);
253 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
255 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
256 struct dma_buf *dma_buf)
258 struct dma_buf_attachment *attach;
259 struct sg_table *sgt;
260 struct drm_gem_object *obj;
263 if (!dev->driver->gem_prime_import_sg_table)
264 return ERR_PTR(-EINVAL);
266 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
268 if (obj->dev == dev) {
270 * Importing dmabuf exported from out own gem increases
271 * refcount on gem itself instead of f_count of dmabuf.
273 drm_gem_object_reference(obj);
278 attach = dma_buf_attach(dma_buf, dev->dev);
280 return ERR_PTR(PTR_ERR(attach));
282 get_dma_buf(dma_buf);
284 sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
285 if (IS_ERR_OR_NULL(sgt)) {
290 obj = dev->driver->gem_prime_import_sg_table(dev, dma_buf->size, sgt);
296 obj->import_attach = attach;
301 dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
303 dma_buf_detach(dma_buf, attach);
304 dma_buf_put(dma_buf);
308 EXPORT_SYMBOL(drm_gem_prime_import);
310 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
311 struct drm_file *file_priv, int prime_fd, uint32_t *handle)
313 struct dma_buf *dma_buf;
314 struct drm_gem_object *obj;
317 dma_buf = dma_buf_get(prime_fd);
319 return PTR_ERR(dma_buf);
321 mutex_lock(&file_priv->prime.lock);
323 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
330 /* never seen this one, need to import */
331 obj = dev->driver->gem_prime_import(dev, dma_buf);
337 ret = drm_gem_handle_create(file_priv, obj, handle);
338 drm_gem_object_unreference_unlocked(obj);
342 ret = drm_prime_add_buf_handle(&file_priv->prime,
347 mutex_unlock(&file_priv->prime.lock);
349 dma_buf_put(dma_buf);
354 /* hmm, if driver attached, we are relying on the free-object path
355 * to detach.. which seems ok..
357 drm_gem_object_handle_unreference_unlocked(obj);
359 dma_buf_put(dma_buf);
360 mutex_unlock(&file_priv->prime.lock);
363 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
365 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
366 struct drm_file *file_priv)
368 struct drm_prime_handle *args = data;
371 if (!drm_core_check_feature(dev, DRIVER_PRIME))
374 if (!dev->driver->prime_handle_to_fd)
377 /* check flags are valid */
378 if (args->flags & ~DRM_CLOEXEC)
381 /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
382 flags = args->flags & DRM_CLOEXEC;
384 return dev->driver->prime_handle_to_fd(dev, file_priv,
385 args->handle, flags, &args->fd);
388 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
389 struct drm_file *file_priv)
391 struct drm_prime_handle *args = data;
393 if (!drm_core_check_feature(dev, DRIVER_PRIME))
396 if (!dev->driver->prime_fd_to_handle)
399 return dev->driver->prime_fd_to_handle(dev, file_priv,
400 args->fd, &args->handle);
404 * drm_prime_pages_to_sg
406 * this helper creates an sg table object from a set of pages
407 * the driver is responsible for mapping the pages into the
408 * importers address space
410 struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
412 struct sg_table *sg = NULL;
415 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
419 ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
420 nr_pages << PAGE_SHIFT, GFP_KERNEL);
429 EXPORT_SYMBOL(drm_prime_pages_to_sg);
431 /* export an sg table into an array of pages and addresses
432 this is currently required by the TTM driver in order to do correct fault
434 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
435 dma_addr_t *addrs, int max_pages)
438 struct scatterlist *sg;
445 for_each_sg(sgt->sgl, sg, sgt->nents, count) {
449 addr = sg_dma_address(sg);
452 if (WARN_ON(pg_index >= max_pages))
454 pages[pg_index] = page;
456 addrs[pg_index] = addr;
466 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
467 /* helper function to cleanup a GEM/prime object */
468 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
470 struct dma_buf_attachment *attach;
471 struct dma_buf *dma_buf;
472 attach = obj->import_attach;
474 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
475 dma_buf = attach->dmabuf;
476 dma_buf_detach(attach->dmabuf, attach);
477 /* remove the reference */
478 dma_buf_put(dma_buf);
480 EXPORT_SYMBOL(drm_prime_gem_destroy);
482 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
484 INIT_LIST_HEAD(&prime_fpriv->head);
485 mutex_init(&prime_fpriv->lock);
487 EXPORT_SYMBOL(drm_prime_init_file_private);
489 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
491 /* by now drm_gem_release should've made sure the list is empty */
492 WARN_ON(!list_empty(&prime_fpriv->head));
494 EXPORT_SYMBOL(drm_prime_destroy_file_private);
496 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle)
498 struct drm_prime_member *member;
500 member = kmalloc(sizeof(*member), GFP_KERNEL);
504 get_dma_buf(dma_buf);
505 member->dma_buf = dma_buf;
506 member->handle = handle;
507 list_add(&member->entry, &prime_fpriv->head);
511 int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle)
513 struct drm_prime_member *member;
515 list_for_each_entry(member, &prime_fpriv->head, entry) {
516 if (member->dma_buf == dma_buf) {
517 *handle = member->handle;
523 EXPORT_SYMBOL(drm_prime_lookup_buf_handle);
525 void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf)
527 struct drm_prime_member *member, *safe;
529 mutex_lock(&prime_fpriv->lock);
530 list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
531 if (member->dma_buf == dma_buf) {
532 dma_buf_put(dma_buf);
533 list_del(&member->entry);
537 mutex_unlock(&prime_fpriv->lock);
539 EXPORT_SYMBOL(drm_prime_remove_buf_handle);