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 static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
67 enum dma_data_direction dir)
69 struct drm_gem_object *obj = attach->dmabuf->priv;
72 mutex_lock(&obj->dev->struct_mutex);
74 sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
76 if (!IS_ERR_OR_NULL(sgt))
77 dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir);
79 mutex_unlock(&obj->dev->struct_mutex);
83 static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
84 struct sg_table *sgt, enum dma_data_direction dir)
86 dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir);
91 static void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
93 struct drm_gem_object *obj = dma_buf->priv;
95 if (obj->export_dma_buf == dma_buf) {
96 /* drop the reference on the export fd holds */
97 obj->export_dma_buf = NULL;
98 drm_gem_object_unreference_unlocked(obj);
102 static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
104 struct drm_gem_object *obj = dma_buf->priv;
105 struct drm_device *dev = obj->dev;
107 return dev->driver->gem_prime_vmap(obj);
110 static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
112 struct drm_gem_object *obj = dma_buf->priv;
113 struct drm_device *dev = obj->dev;
115 dev->driver->gem_prime_vunmap(obj, vaddr);
118 static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
119 unsigned long page_num)
124 static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
125 unsigned long page_num, void *addr)
129 static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
130 unsigned long page_num)
135 static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
136 unsigned long page_num, void *addr)
141 static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
142 struct vm_area_struct *vma)
147 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
148 .map_dma_buf = drm_gem_map_dma_buf,
149 .unmap_dma_buf = drm_gem_unmap_dma_buf,
150 .release = drm_gem_dmabuf_release,
151 .kmap = drm_gem_dmabuf_kmap,
152 .kmap_atomic = drm_gem_dmabuf_kmap_atomic,
153 .kunmap = drm_gem_dmabuf_kunmap,
154 .kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
155 .mmap = drm_gem_dmabuf_mmap,
156 .vmap = drm_gem_dmabuf_vmap,
157 .vunmap = drm_gem_dmabuf_vunmap,
163 * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
164 * simpler APIs by using the helper functions @drm_gem_prime_export and
165 * @drm_gem_prime_import. These functions implement dma-buf support in terms of
166 * five lower-level driver callbacks:
170 * - @gem_prime_pin (optional): prepare a GEM object for exporting
172 * - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
174 * - @gem_prime_vmap: vmap a buffer exported by your driver
176 * - @gem_prime_vunmap: vunmap a buffer exported by your driver
180 * - @gem_prime_import_sg_table (import): produce a GEM object from another
181 * driver's scatter/gather table
184 struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
185 struct drm_gem_object *obj, int flags)
187 if (dev->driver->gem_prime_pin) {
188 int ret = dev->driver->gem_prime_pin(obj);
192 return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size, flags);
194 EXPORT_SYMBOL(drm_gem_prime_export);
196 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
197 struct drm_file *file_priv, uint32_t handle, uint32_t flags,
200 struct drm_gem_object *obj;
203 struct dma_buf *dmabuf;
205 obj = drm_gem_object_lookup(dev, file_priv, handle);
209 mutex_lock(&file_priv->prime.lock);
210 /* re-export the original imported object */
211 if (obj->import_attach) {
212 dmabuf = obj->import_attach->dmabuf;
216 if (obj->export_dma_buf) {
217 dmabuf = obj->export_dma_buf;
221 buf = dev->driver->gem_prime_export(dev, obj, flags);
223 /* normally the created dma-buf takes ownership of the ref,
224 * but if that fails then drop the ref
229 obj->export_dma_buf = buf;
231 /* if we've exported this buffer the cheat and add it to the import list
232 * so we get the correct handle back
234 ret = drm_prime_add_buf_handle(&file_priv->prime,
235 obj->export_dma_buf, handle);
239 *prime_fd = dma_buf_fd(buf, flags);
240 mutex_unlock(&file_priv->prime.lock);
245 *prime_fd = dma_buf_fd(dmabuf, flags);
247 drm_gem_object_unreference_unlocked(obj);
248 mutex_unlock(&file_priv->prime.lock);
251 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
253 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
254 struct dma_buf *dma_buf)
256 struct dma_buf_attachment *attach;
257 struct sg_table *sgt;
258 struct drm_gem_object *obj;
261 if (!dev->driver->gem_prime_import_sg_table)
262 return ERR_PTR(-EINVAL);
264 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
266 if (obj->dev == dev) {
268 * Importing dmabuf exported from out own gem increases
269 * refcount on gem itself instead of f_count of dmabuf.
271 drm_gem_object_reference(obj);
276 attach = dma_buf_attach(dma_buf, dev->dev);
278 return ERR_PTR(PTR_ERR(attach));
280 get_dma_buf(dma_buf);
282 sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
283 if (IS_ERR_OR_NULL(sgt)) {
288 obj = dev->driver->gem_prime_import_sg_table(dev, dma_buf->size, sgt);
294 obj->import_attach = attach;
299 dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
301 dma_buf_detach(dma_buf, attach);
302 dma_buf_put(dma_buf);
306 EXPORT_SYMBOL(drm_gem_prime_import);
308 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
309 struct drm_file *file_priv, int prime_fd, uint32_t *handle)
311 struct dma_buf *dma_buf;
312 struct drm_gem_object *obj;
315 dma_buf = dma_buf_get(prime_fd);
317 return PTR_ERR(dma_buf);
319 mutex_lock(&file_priv->prime.lock);
321 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
328 /* never seen this one, need to import */
329 obj = dev->driver->gem_prime_import(dev, dma_buf);
335 ret = drm_gem_handle_create(file_priv, obj, handle);
336 drm_gem_object_unreference_unlocked(obj);
340 ret = drm_prime_add_buf_handle(&file_priv->prime,
345 mutex_unlock(&file_priv->prime.lock);
347 dma_buf_put(dma_buf);
352 /* hmm, if driver attached, we are relying on the free-object path
353 * to detach.. which seems ok..
355 drm_gem_object_handle_unreference_unlocked(obj);
357 dma_buf_put(dma_buf);
358 mutex_unlock(&file_priv->prime.lock);
361 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
363 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
364 struct drm_file *file_priv)
366 struct drm_prime_handle *args = data;
369 if (!drm_core_check_feature(dev, DRIVER_PRIME))
372 if (!dev->driver->prime_handle_to_fd)
375 /* check flags are valid */
376 if (args->flags & ~DRM_CLOEXEC)
379 /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
380 flags = args->flags & DRM_CLOEXEC;
382 return dev->driver->prime_handle_to_fd(dev, file_priv,
383 args->handle, flags, &args->fd);
386 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
387 struct drm_file *file_priv)
389 struct drm_prime_handle *args = data;
391 if (!drm_core_check_feature(dev, DRIVER_PRIME))
394 if (!dev->driver->prime_fd_to_handle)
397 return dev->driver->prime_fd_to_handle(dev, file_priv,
398 args->fd, &args->handle);
402 * drm_prime_pages_to_sg
404 * this helper creates an sg table object from a set of pages
405 * the driver is responsible for mapping the pages into the
406 * importers address space
408 struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
410 struct sg_table *sg = NULL;
413 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
417 ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
418 nr_pages << PAGE_SHIFT, GFP_KERNEL);
427 EXPORT_SYMBOL(drm_prime_pages_to_sg);
429 /* export an sg table into an array of pages and addresses
430 this is currently required by the TTM driver in order to do correct fault
432 int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
433 dma_addr_t *addrs, int max_pages)
436 struct scatterlist *sg;
443 for_each_sg(sgt->sgl, sg, sgt->nents, count) {
447 addr = sg_dma_address(sg);
450 if (WARN_ON(pg_index >= max_pages))
452 pages[pg_index] = page;
454 addrs[pg_index] = addr;
464 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
465 /* helper function to cleanup a GEM/prime object */
466 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
468 struct dma_buf_attachment *attach;
469 struct dma_buf *dma_buf;
470 attach = obj->import_attach;
472 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
473 dma_buf = attach->dmabuf;
474 dma_buf_detach(attach->dmabuf, attach);
475 /* remove the reference */
476 dma_buf_put(dma_buf);
478 EXPORT_SYMBOL(drm_prime_gem_destroy);
480 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
482 INIT_LIST_HEAD(&prime_fpriv->head);
483 mutex_init(&prime_fpriv->lock);
485 EXPORT_SYMBOL(drm_prime_init_file_private);
487 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
489 /* by now drm_gem_release should've made sure the list is empty */
490 WARN_ON(!list_empty(&prime_fpriv->head));
492 EXPORT_SYMBOL(drm_prime_destroy_file_private);
494 int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle)
496 struct drm_prime_member *member;
498 member = kmalloc(sizeof(*member), GFP_KERNEL);
502 get_dma_buf(dma_buf);
503 member->dma_buf = dma_buf;
504 member->handle = handle;
505 list_add(&member->entry, &prime_fpriv->head);
508 EXPORT_SYMBOL(drm_prime_add_buf_handle);
510 int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle)
512 struct drm_prime_member *member;
514 list_for_each_entry(member, &prime_fpriv->head, entry) {
515 if (member->dma_buf == dma_buf) {
516 *handle = member->handle;
522 EXPORT_SYMBOL(drm_prime_lookup_buf_handle);
524 void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf)
526 struct drm_prime_member *member, *safe;
528 mutex_lock(&prime_fpriv->lock);
529 list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
530 if (member->dma_buf == dma_buf) {
531 dma_buf_put(dma_buf);
532 list_del(&member->entry);
536 mutex_unlock(&prime_fpriv->lock);
538 EXPORT_SYMBOL(drm_prime_remove_buf_handle);