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>
31 #include <linux/rbtree.h>
34 #include <drm/drm_drv.h>
35 #include <drm/drm_file.h>
36 #include <drm/drm_framebuffer.h>
37 #include <drm/drm_gem.h>
38 #include <drm/drm_prime.h>
40 #include "drm_internal.h"
43 * DOC: overview and lifetime rules
45 * Similar to GEM global names, PRIME file descriptors are also used to share
46 * buffer objects across processes. They offer additional security: as file
47 * descriptors must be explicitly sent over UNIX domain sockets to be shared
48 * between applications, they can't be guessed like the globally unique GEM
51 * Drivers that support the PRIME API implement the
52 * &drm_driver.prime_handle_to_fd and &drm_driver.prime_fd_to_handle operations.
53 * GEM based drivers must use drm_gem_prime_handle_to_fd() and
54 * drm_gem_prime_fd_to_handle() to implement these. For GEM based drivers the
55 * actual driver interfaces is provided through the &drm_gem_object_funcs.export
56 * and &drm_driver.gem_prime_import hooks.
58 * &dma_buf_ops implementations for GEM drivers are all individually exported
59 * for drivers which need to overwrite or reimplement some of them.
61 * Reference Counting for GEM Drivers
62 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
64 * On the export the &dma_buf holds a reference to the exported buffer object,
65 * usually a &drm_gem_object. It takes this reference in the PRIME_HANDLE_TO_FD
66 * IOCTL, when it first calls &drm_gem_object_funcs.export
67 * and stores the exporting GEM object in the &dma_buf.priv field. This
68 * reference needs to be released when the final reference to the &dma_buf
69 * itself is dropped and its &dma_buf_ops.release function is called. For
70 * GEM-based drivers, the &dma_buf should be exported using
71 * drm_gem_dmabuf_export() and then released by drm_gem_dmabuf_release().
73 * Thus the chain of references always flows in one direction, avoiding loops:
74 * importing GEM object -> dma-buf -> exported GEM bo. A further complication
75 * are the lookup caches for import and export. These are required to guarantee
76 * that any given object will always have only one unique userspace handle. This
77 * is required to allow userspace to detect duplicated imports, since some GEM
78 * drivers do fail command submissions if a given buffer object is listed more
79 * than once. These import and export caches in &drm_prime_file_private only
80 * retain a weak reference, which is cleaned up when the corresponding object is
83 * Self-importing: If userspace is using PRIME as a replacement for flink then
84 * it will get a fd->handle request for a GEM object that it created. Drivers
85 * should detect this situation and return back the underlying object from the
86 * dma-buf private. For GEM based drivers this is handled in
87 * drm_gem_prime_import() already.
90 struct drm_prime_member {
91 struct dma_buf *dma_buf;
94 struct rb_node dmabuf_rb;
95 struct rb_node handle_rb;
98 static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
99 struct dma_buf *dma_buf, uint32_t handle)
101 struct drm_prime_member *member;
102 struct rb_node **p, *rb;
104 member = kmalloc(sizeof(*member), GFP_KERNEL);
108 get_dma_buf(dma_buf);
109 member->dma_buf = dma_buf;
110 member->handle = handle;
113 p = &prime_fpriv->dmabufs.rb_node;
115 struct drm_prime_member *pos;
118 pos = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
119 if (dma_buf > pos->dma_buf)
124 rb_link_node(&member->dmabuf_rb, rb, p);
125 rb_insert_color(&member->dmabuf_rb, &prime_fpriv->dmabufs);
128 p = &prime_fpriv->handles.rb_node;
130 struct drm_prime_member *pos;
133 pos = rb_entry(rb, struct drm_prime_member, handle_rb);
134 if (handle > pos->handle)
139 rb_link_node(&member->handle_rb, rb, p);
140 rb_insert_color(&member->handle_rb, &prime_fpriv->handles);
145 static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
150 rb = prime_fpriv->handles.rb_node;
152 struct drm_prime_member *member;
154 member = rb_entry(rb, struct drm_prime_member, handle_rb);
155 if (member->handle == handle)
156 return member->dma_buf;
157 else if (member->handle < handle)
166 static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
167 struct dma_buf *dma_buf,
172 rb = prime_fpriv->dmabufs.rb_node;
174 struct drm_prime_member *member;
176 member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
177 if (member->dma_buf == dma_buf) {
178 *handle = member->handle;
180 } else if (member->dma_buf < dma_buf) {
190 void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv,
195 mutex_lock(&prime_fpriv->lock);
197 rb = prime_fpriv->handles.rb_node;
199 struct drm_prime_member *member;
201 member = rb_entry(rb, struct drm_prime_member, handle_rb);
202 if (member->handle == handle) {
203 rb_erase(&member->handle_rb, &prime_fpriv->handles);
204 rb_erase(&member->dmabuf_rb, &prime_fpriv->dmabufs);
206 dma_buf_put(member->dma_buf);
209 } else if (member->handle < handle) {
216 mutex_unlock(&prime_fpriv->lock);
219 void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
221 mutex_init(&prime_fpriv->lock);
222 prime_fpriv->dmabufs = RB_ROOT;
223 prime_fpriv->handles = RB_ROOT;
226 void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
228 /* by now drm_gem_release should've made sure the list is empty */
229 WARN_ON(!RB_EMPTY_ROOT(&prime_fpriv->dmabufs));
233 * drm_gem_dmabuf_export - &dma_buf export implementation for GEM
234 * @dev: parent device for the exported dmabuf
235 * @exp_info: the export information used by dma_buf_export()
237 * This wraps dma_buf_export() for use by generic GEM drivers that are using
238 * drm_gem_dmabuf_release(). In addition to calling dma_buf_export(), we take
239 * a reference to the &drm_device and the exported &drm_gem_object (stored in
240 * &dma_buf_export_info.priv) which is released by drm_gem_dmabuf_release().
242 * Returns the new dmabuf.
244 struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
245 struct dma_buf_export_info *exp_info)
247 struct drm_gem_object *obj = exp_info->priv;
248 struct dma_buf *dma_buf;
250 dma_buf = dma_buf_export(exp_info);
255 drm_gem_object_get(obj);
256 dma_buf->file->f_mapping = obj->dev->anon_inode->i_mapping;
260 EXPORT_SYMBOL(drm_gem_dmabuf_export);
263 * drm_gem_dmabuf_release - &dma_buf release implementation for GEM
264 * @dma_buf: buffer to be released
266 * Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
267 * must use this in their &dma_buf_ops structure as the release callback.
268 * drm_gem_dmabuf_release() should be used in conjunction with
269 * drm_gem_dmabuf_export().
271 void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
273 struct drm_gem_object *obj = dma_buf->priv;
274 struct drm_device *dev = obj->dev;
276 /* drop the reference on the export fd holds */
277 drm_gem_object_put(obj);
281 EXPORT_SYMBOL(drm_gem_dmabuf_release);
284 * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
285 * @dev: dev to export the buffer from
286 * @file_priv: drm file-private structure
287 * @prime_fd: fd id of the dma-buf which should be imported
288 * @handle: pointer to storage for the handle of the imported buffer object
290 * This is the PRIME import function which must be used mandatorily by GEM
291 * drivers to ensure correct lifetime management of the underlying GEM object.
292 * The actual importing of GEM object from the dma-buf is done through the
293 * &drm_driver.gem_prime_import driver callback.
295 * Returns 0 on success or a negative error code on failure.
297 int drm_gem_prime_fd_to_handle(struct drm_device *dev,
298 struct drm_file *file_priv, int prime_fd,
301 struct dma_buf *dma_buf;
302 struct drm_gem_object *obj;
305 dma_buf = dma_buf_get(prime_fd);
307 return PTR_ERR(dma_buf);
309 mutex_lock(&file_priv->prime.lock);
311 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
316 /* never seen this one, need to import */
317 mutex_lock(&dev->object_name_lock);
318 if (dev->driver->gem_prime_import)
319 obj = dev->driver->gem_prime_import(dev, dma_buf);
321 obj = drm_gem_prime_import(dev, dma_buf);
328 WARN_ON(obj->dma_buf != dma_buf);
330 obj->dma_buf = dma_buf;
331 get_dma_buf(dma_buf);
334 /* _handle_create_tail unconditionally unlocks dev->object_name_lock. */
335 ret = drm_gem_handle_create_tail(file_priv, obj, handle);
336 drm_gem_object_put(obj);
340 ret = drm_prime_add_buf_handle(&file_priv->prime,
342 mutex_unlock(&file_priv->prime.lock);
346 dma_buf_put(dma_buf);
351 /* hmm, if driver attached, we are relying on the free-object path
352 * to detach.. which seems ok..
354 drm_gem_handle_delete(file_priv, *handle);
355 dma_buf_put(dma_buf);
359 mutex_unlock(&dev->object_name_lock);
361 mutex_unlock(&file_priv->prime.lock);
362 dma_buf_put(dma_buf);
365 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
367 int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
368 struct drm_file *file_priv)
370 struct drm_prime_handle *args = data;
372 if (!dev->driver->prime_fd_to_handle)
375 return dev->driver->prime_fd_to_handle(dev, file_priv,
376 args->fd, &args->handle);
379 static struct dma_buf *export_and_register_object(struct drm_device *dev,
380 struct drm_gem_object *obj,
383 struct dma_buf *dmabuf;
385 /* prevent races with concurrent gem_close. */
386 if (obj->handle_count == 0) {
387 dmabuf = ERR_PTR(-ENOENT);
391 if (obj->funcs && obj->funcs->export)
392 dmabuf = obj->funcs->export(obj, flags);
394 dmabuf = drm_gem_prime_export(obj, flags);
395 if (IS_ERR(dmabuf)) {
396 /* normally the created dma-buf takes ownership of the ref,
397 * but if that fails then drop the ref
403 * Note that callers do not need to clean up the export cache
404 * since the check for obj->handle_count guarantees that someone
407 obj->dma_buf = dmabuf;
408 get_dma_buf(obj->dma_buf);
414 * drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
415 * @dev: dev to export the buffer from
416 * @file_priv: drm file-private structure
417 * @handle: buffer handle to export
418 * @flags: flags like DRM_CLOEXEC
419 * @prime_fd: pointer to storage for the fd id of the create dma-buf
421 * This is the PRIME export function which must be used mandatorily by GEM
422 * drivers to ensure correct lifetime management of the underlying GEM object.
423 * The actual exporting from GEM object to a dma-buf is done through the
424 * &drm_gem_object_funcs.export callback.
426 int drm_gem_prime_handle_to_fd(struct drm_device *dev,
427 struct drm_file *file_priv, uint32_t handle,
431 struct drm_gem_object *obj;
433 struct dma_buf *dmabuf;
435 mutex_lock(&file_priv->prime.lock);
436 obj = drm_gem_object_lookup(file_priv, handle);
442 dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
445 goto out_have_handle;
448 mutex_lock(&dev->object_name_lock);
449 /* re-export the original imported object */
450 if (obj->import_attach) {
451 dmabuf = obj->import_attach->dmabuf;
457 get_dma_buf(obj->dma_buf);
458 dmabuf = obj->dma_buf;
462 dmabuf = export_and_register_object(dev, obj, flags);
463 if (IS_ERR(dmabuf)) {
464 /* normally the created dma-buf takes ownership of the ref,
465 * but if that fails then drop the ref
467 ret = PTR_ERR(dmabuf);
468 mutex_unlock(&dev->object_name_lock);
474 * If we've exported this buffer then cheat and add it to the import list
475 * so we get the correct handle back. We must do this under the
476 * protection of dev->object_name_lock to ensure that a racing gem close
477 * ioctl doesn't miss to remove this buffer handle from the cache.
479 ret = drm_prime_add_buf_handle(&file_priv->prime,
481 mutex_unlock(&dev->object_name_lock);
483 goto fail_put_dmabuf;
486 ret = dma_buf_fd(dmabuf, flags);
488 * We must _not_ remove the buffer from the handle cache since the newly
489 * created dma buf is already linked in the global obj->dma_buf pointer,
490 * and that is invariant as long as a userspace gem handle exists.
491 * Closing the handle will clean out the cache anyway, so we don't leak.
494 goto fail_put_dmabuf;
505 drm_gem_object_put(obj);
507 mutex_unlock(&file_priv->prime.lock);
511 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
513 int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
514 struct drm_file *file_priv)
516 struct drm_prime_handle *args = data;
518 if (!dev->driver->prime_handle_to_fd)
521 /* check flags are valid */
522 if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR))
525 return dev->driver->prime_handle_to_fd(dev, file_priv,
526 args->handle, args->flags, &args->fd);
532 * Drivers can implement &drm_gem_object_funcs.export and
533 * &drm_driver.gem_prime_import in terms of simpler APIs by using the helper
534 * functions drm_gem_prime_export() and drm_gem_prime_import(). These functions
535 * implement dma-buf support in terms of some lower-level helpers, which are
536 * again exported for drivers to use individually:
541 * Optional pinning of buffers is handled at dma-buf attach and detach time in
542 * drm_gem_map_attach() and drm_gem_map_detach(). Backing storage itself is
543 * handled by drm_gem_map_dma_buf() and drm_gem_unmap_dma_buf(), which relies on
544 * &drm_gem_object_funcs.get_sg_table.
546 * For kernel-internal access there's drm_gem_dmabuf_vmap() and
547 * drm_gem_dmabuf_vunmap(). Userspace mmap support is provided by
548 * drm_gem_dmabuf_mmap().
550 * Note that these export helpers can only be used if the underlying backing
551 * storage is fully coherent and either permanently pinned, or it is safe to pin
554 * FIXME: The underlying helper functions are named rather inconsistently.
559 * Importing dma-bufs using drm_gem_prime_import() relies on
560 * &drm_driver.gem_prime_import_sg_table.
562 * Note that similarly to the export helpers this permanently pins the
563 * underlying backing storage. Which is ok for scanout, but is not the best
564 * option for sharing lots of buffers for rendering.
568 * drm_gem_map_attach - dma_buf attach implementation for GEM
569 * @dma_buf: buffer to attach device to
570 * @attach: buffer attachment data
572 * Calls &drm_gem_object_funcs.pin for device specific handling. This can be
573 * used as the &dma_buf_ops.attach callback. Must be used together with
574 * drm_gem_map_detach().
576 * Returns 0 on success, negative error code on failure.
578 int drm_gem_map_attach(struct dma_buf *dma_buf,
579 struct dma_buf_attachment *attach)
581 struct drm_gem_object *obj = dma_buf->priv;
583 return drm_gem_pin(obj);
585 EXPORT_SYMBOL(drm_gem_map_attach);
588 * drm_gem_map_detach - dma_buf detach implementation for GEM
589 * @dma_buf: buffer to detach from
590 * @attach: attachment to be detached
592 * Calls &drm_gem_object_funcs.pin for device specific handling. Cleans up
593 * &dma_buf_attachment from drm_gem_map_attach(). This can be used as the
594 * &dma_buf_ops.detach callback.
596 void drm_gem_map_detach(struct dma_buf *dma_buf,
597 struct dma_buf_attachment *attach)
599 struct drm_gem_object *obj = dma_buf->priv;
603 EXPORT_SYMBOL(drm_gem_map_detach);
606 * drm_gem_map_dma_buf - map_dma_buf implementation for GEM
607 * @attach: attachment whose scatterlist is to be returned
608 * @dir: direction of DMA transfer
610 * Calls &drm_gem_object_funcs.get_sg_table and then maps the scatterlist. This
611 * can be used as the &dma_buf_ops.map_dma_buf callback. Should be used together
612 * with drm_gem_unmap_dma_buf().
614 * Returns:sg_table containing the scatterlist to be returned; returns ERR_PTR
615 * on error. May return -EINTR if it is interrupted by a signal.
617 struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
618 enum dma_data_direction dir)
620 struct drm_gem_object *obj = attach->dmabuf->priv;
621 struct sg_table *sgt;
624 if (WARN_ON(dir == DMA_NONE))
625 return ERR_PTR(-EINVAL);
627 if (WARN_ON(!obj->funcs->get_sg_table))
628 return ERR_PTR(-ENOSYS);
630 sgt = obj->funcs->get_sg_table(obj);
634 ret = dma_map_sgtable(attach->dev, sgt, dir,
635 DMA_ATTR_SKIP_CPU_SYNC);
644 EXPORT_SYMBOL(drm_gem_map_dma_buf);
647 * drm_gem_unmap_dma_buf - unmap_dma_buf implementation for GEM
648 * @attach: attachment to unmap buffer from
649 * @sgt: scatterlist info of the buffer to unmap
650 * @dir: direction of DMA transfer
652 * This can be used as the &dma_buf_ops.unmap_dma_buf callback.
654 void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
655 struct sg_table *sgt,
656 enum dma_data_direction dir)
661 dma_unmap_sgtable(attach->dev, sgt, dir, DMA_ATTR_SKIP_CPU_SYNC);
665 EXPORT_SYMBOL(drm_gem_unmap_dma_buf);
668 * drm_gem_dmabuf_vmap - dma_buf vmap implementation for GEM
669 * @dma_buf: buffer to be mapped
670 * @map: the virtual address of the buffer
672 * Sets up a kernel virtual mapping. This can be used as the &dma_buf_ops.vmap
673 * callback. Calls into &drm_gem_object_funcs.vmap for device specific handling.
674 * The kernel virtual address is returned in map.
676 * Returns 0 on success or a negative errno code otherwise.
678 int drm_gem_dmabuf_vmap(struct dma_buf *dma_buf, struct dma_buf_map *map)
680 struct drm_gem_object *obj = dma_buf->priv;
682 return drm_gem_vmap(obj, map);
684 EXPORT_SYMBOL(drm_gem_dmabuf_vmap);
687 * drm_gem_dmabuf_vunmap - dma_buf vunmap implementation for GEM
688 * @dma_buf: buffer to be unmapped
689 * @map: the virtual address of the buffer
691 * Releases a kernel virtual mapping. This can be used as the
692 * &dma_buf_ops.vunmap callback. Calls into &drm_gem_object_funcs.vunmap for device specific handling.
694 void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, struct dma_buf_map *map)
696 struct drm_gem_object *obj = dma_buf->priv;
698 drm_gem_vunmap(obj, map);
700 EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);
703 * drm_gem_prime_mmap - PRIME mmap function for GEM drivers
705 * @vma: Virtual address range
707 * This function sets up a userspace mapping for PRIME exported buffers using
708 * the same codepath that is used for regular GEM buffer mapping on the DRM fd.
709 * The fake GEM offset is added to vma->vm_pgoff and &drm_driver->fops->mmap is
710 * called to set up the mapping.
712 * Drivers can use this as their &drm_driver.gem_prime_mmap callback.
714 int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
716 struct drm_file *priv;
720 /* Add the fake offset */
721 vma->vm_pgoff += drm_vma_node_start(&obj->vma_node);
723 if (obj->funcs && obj->funcs->mmap) {
724 vma->vm_ops = obj->funcs->vm_ops;
726 drm_gem_object_get(obj);
727 ret = obj->funcs->mmap(obj, vma);
729 drm_gem_object_put(obj);
732 vma->vm_private_data = obj;
736 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
737 fil = kzalloc(sizeof(*fil), GFP_KERNEL);
743 /* Used by drm_gem_mmap() to lookup the GEM object */
744 priv->minor = obj->dev->primary;
745 fil->private_data = priv;
747 ret = drm_vma_node_allow(&obj->vma_node, priv);
751 ret = obj->dev->driver->fops->mmap(fil, vma);
753 drm_vma_node_revoke(&obj->vma_node, priv);
760 EXPORT_SYMBOL(drm_gem_prime_mmap);
763 * drm_gem_dmabuf_mmap - dma_buf mmap implementation for GEM
764 * @dma_buf: buffer to be mapped
765 * @vma: virtual address range
767 * Provides memory mapping for the buffer. This can be used as the
768 * &dma_buf_ops.mmap callback. It just forwards to &drm_driver.gem_prime_mmap,
769 * which should be set to drm_gem_prime_mmap().
771 * FIXME: There's really no point to this wrapper, drivers which need anything
772 * else but drm_gem_prime_mmap can roll their own &dma_buf_ops.mmap callback.
774 * Returns 0 on success or a negative error code on failure.
776 int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
778 struct drm_gem_object *obj = dma_buf->priv;
779 struct drm_device *dev = obj->dev;
781 if (!dev->driver->gem_prime_mmap)
784 return dev->driver->gem_prime_mmap(obj, vma);
786 EXPORT_SYMBOL(drm_gem_dmabuf_mmap);
788 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
789 .cache_sgt_mapping = true,
790 .attach = drm_gem_map_attach,
791 .detach = drm_gem_map_detach,
792 .map_dma_buf = drm_gem_map_dma_buf,
793 .unmap_dma_buf = drm_gem_unmap_dma_buf,
794 .release = drm_gem_dmabuf_release,
795 .mmap = drm_gem_dmabuf_mmap,
796 .vmap = drm_gem_dmabuf_vmap,
797 .vunmap = drm_gem_dmabuf_vunmap,
801 * drm_prime_pages_to_sg - converts a page array into an sg list
803 * @pages: pointer to the array of page pointers to convert
804 * @nr_pages: length of the page vector
806 * This helper creates an sg table object from a set of pages
807 * the driver is responsible for mapping the pages into the
808 * importers address space for use with dma_buf itself.
810 * This is useful for implementing &drm_gem_object_funcs.get_sg_table.
812 struct sg_table *drm_prime_pages_to_sg(struct drm_device *dev,
813 struct page **pages, unsigned int nr_pages)
816 size_t max_segment = 0;
819 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
821 return ERR_PTR(-ENOMEM);
824 max_segment = dma_max_mapping_size(dev->dev);
825 if (max_segment == 0)
826 max_segment = UINT_MAX;
827 err = sg_alloc_table_from_pages_segment(sg, pages, nr_pages, 0,
828 nr_pages << PAGE_SHIFT,
829 max_segment, GFP_KERNEL);
836 EXPORT_SYMBOL(drm_prime_pages_to_sg);
839 * drm_prime_get_contiguous_size - returns the contiguous size of the buffer
840 * @sgt: sg_table describing the buffer to check
842 * This helper calculates the contiguous size in the DMA address space
843 * of the the buffer described by the provided sg_table.
845 * This is useful for implementing
846 * &drm_gem_object_funcs.gem_prime_import_sg_table.
848 unsigned long drm_prime_get_contiguous_size(struct sg_table *sgt)
850 dma_addr_t expected = sg_dma_address(sgt->sgl);
851 struct scatterlist *sg;
852 unsigned long size = 0;
855 for_each_sgtable_dma_sg(sgt, sg, i) {
856 unsigned int len = sg_dma_len(sg);
860 if (sg_dma_address(sg) != expected)
867 EXPORT_SYMBOL(drm_prime_get_contiguous_size);
870 * drm_gem_prime_export - helper library implementation of the export callback
871 * @obj: GEM object to export
872 * @flags: flags like DRM_CLOEXEC and DRM_RDWR
874 * This is the implementation of the &drm_gem_object_funcs.export functions for GEM drivers
875 * using the PRIME helpers. It is used as the default in
876 * drm_gem_prime_handle_to_fd().
878 struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj,
881 struct drm_device *dev = obj->dev;
882 struct dma_buf_export_info exp_info = {
883 .exp_name = KBUILD_MODNAME, /* white lie for debug */
884 .owner = dev->driver->fops->owner,
885 .ops = &drm_gem_prime_dmabuf_ops,
892 return drm_gem_dmabuf_export(dev, &exp_info);
894 EXPORT_SYMBOL(drm_gem_prime_export);
897 * drm_gem_prime_import_dev - core implementation of the import callback
898 * @dev: drm_device to import into
899 * @dma_buf: dma-buf object to import
900 * @attach_dev: struct device to dma_buf attach
902 * This is the core of drm_gem_prime_import(). It's designed to be called by
903 * drivers who want to use a different device structure than &drm_device.dev for
904 * attaching via dma_buf. This function calls
905 * &drm_driver.gem_prime_import_sg_table internally.
907 * Drivers must arrange to call drm_prime_gem_destroy() from their
908 * &drm_gem_object_funcs.free hook when using this function.
910 struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev,
911 struct dma_buf *dma_buf,
912 struct device *attach_dev)
914 struct dma_buf_attachment *attach;
915 struct sg_table *sgt;
916 struct drm_gem_object *obj;
919 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
921 if (obj->dev == dev) {
923 * Importing dmabuf exported from out own gem increases
924 * refcount on gem itself instead of f_count of dmabuf.
926 drm_gem_object_get(obj);
931 if (!dev->driver->gem_prime_import_sg_table)
932 return ERR_PTR(-EINVAL);
934 attach = dma_buf_attach(dma_buf, attach_dev);
936 return ERR_CAST(attach);
938 get_dma_buf(dma_buf);
940 sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
946 obj = dev->driver->gem_prime_import_sg_table(dev, attach, sgt);
952 obj->import_attach = attach;
953 obj->resv = dma_buf->resv;
958 dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
960 dma_buf_detach(dma_buf, attach);
961 dma_buf_put(dma_buf);
965 EXPORT_SYMBOL(drm_gem_prime_import_dev);
968 * drm_gem_prime_import - helper library implementation of the import callback
969 * @dev: drm_device to import into
970 * @dma_buf: dma-buf object to import
972 * This is the implementation of the gem_prime_import functions for GEM drivers
973 * using the PRIME helpers. Drivers can use this as their
974 * &drm_driver.gem_prime_import implementation. It is used as the default
975 * implementation in drm_gem_prime_fd_to_handle().
977 * Drivers must arrange to call drm_prime_gem_destroy() from their
978 * &drm_gem_object_funcs.free hook when using this function.
980 struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
981 struct dma_buf *dma_buf)
983 return drm_gem_prime_import_dev(dev, dma_buf, dev->dev);
985 EXPORT_SYMBOL(drm_gem_prime_import);
988 * drm_prime_sg_to_page_array - convert an sg table into a page array
989 * @sgt: scatter-gather table to convert
990 * @pages: array of page pointers to store the pages in
991 * @max_entries: size of the passed-in array
993 * Exports an sg table into an array of pages.
995 * This function is deprecated and strongly discouraged to be used.
996 * The page array is only useful for page faults and those can corrupt fields
997 * in the struct page if they are not handled by the exporting driver.
999 int __deprecated drm_prime_sg_to_page_array(struct sg_table *sgt,
1000 struct page **pages,
1003 struct sg_page_iter page_iter;
1004 struct page **p = pages;
1006 for_each_sgtable_page(sgt, &page_iter, 0) {
1007 if (WARN_ON(p - pages >= max_entries))
1009 *p++ = sg_page_iter_page(&page_iter);
1013 EXPORT_SYMBOL(drm_prime_sg_to_page_array);
1016 * drm_prime_sg_to_dma_addr_array - convert an sg table into a dma addr array
1017 * @sgt: scatter-gather table to convert
1018 * @addrs: array to store the dma bus address of each page
1019 * @max_entries: size of both the passed-in arrays
1021 * Exports an sg table into an array of addresses.
1023 * Drivers should use this in their &drm_driver.gem_prime_import_sg_table
1026 int drm_prime_sg_to_dma_addr_array(struct sg_table *sgt, dma_addr_t *addrs,
1029 struct sg_dma_page_iter dma_iter;
1030 dma_addr_t *a = addrs;
1032 for_each_sgtable_dma_page(sgt, &dma_iter, 0) {
1033 if (WARN_ON(a - addrs >= max_entries))
1035 *a++ = sg_page_iter_dma_address(&dma_iter);
1039 EXPORT_SYMBOL(drm_prime_sg_to_dma_addr_array);
1042 * drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object
1043 * @obj: GEM object which was created from a dma-buf
1044 * @sg: the sg-table which was pinned at import time
1046 * This is the cleanup functions which GEM drivers need to call when they use
1047 * drm_gem_prime_import() or drm_gem_prime_import_dev() to import dma-bufs.
1049 void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
1051 struct dma_buf_attachment *attach;
1052 struct dma_buf *dma_buf;
1054 attach = obj->import_attach;
1056 dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
1057 dma_buf = attach->dmabuf;
1058 dma_buf_detach(attach->dmabuf, attach);
1059 /* remove the reference */
1060 dma_buf_put(dma_buf);
1062 EXPORT_SYMBOL(drm_prime_gem_destroy);