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 void drm_prime_remove_buf_handle_locked(
134 struct drm_prime_file_private
*prime_fpriv
,
135 struct dma_buf
*dma_buf
)
137 struct drm_prime_member
*member
, *safe
;
139 list_for_each_entry_safe(member
, safe
, &prime_fpriv
->head
, entry
) {
140 if (member
->dma_buf
== dma_buf
) {
141 dma_buf_put(dma_buf
);
142 list_del(&member
->entry
);
148 static struct sg_table
*drm_gem_map_dma_buf(struct dma_buf_attachment
*attach
,
149 enum dma_data_direction dir
)
151 struct drm_prime_attachment
*prime_attach
= attach
->priv
;
152 struct drm_gem_object
*obj
= attach
->dmabuf
->priv
;
153 struct sg_table
*sgt
;
155 if (WARN_ON(dir
== DMA_NONE
|| !prime_attach
))
156 return ERR_PTR(-EINVAL
);
158 /* return the cached mapping when possible */
159 if (prime_attach
->dir
== dir
)
160 return prime_attach
->sgt
;
163 * two mappings with different directions for the same attachment are
166 if (WARN_ON(prime_attach
->dir
!= DMA_NONE
))
167 return ERR_PTR(-EBUSY
);
169 mutex_lock(&obj
->dev
->struct_mutex
);
171 sgt
= obj
->dev
->driver
->gem_prime_get_sg_table(obj
);
174 if (!dma_map_sg(attach
->dev
, sgt
->sgl
, sgt
->nents
, dir
)) {
177 sgt
= ERR_PTR(-ENOMEM
);
179 prime_attach
->sgt
= sgt
;
180 prime_attach
->dir
= dir
;
184 mutex_unlock(&obj
->dev
->struct_mutex
);
188 static void drm_gem_unmap_dma_buf(struct dma_buf_attachment
*attach
,
189 struct sg_table
*sgt
, enum dma_data_direction dir
)
191 /* nothing to be done here */
194 static void drm_gem_dmabuf_release(struct dma_buf
*dma_buf
)
196 struct drm_gem_object
*obj
= dma_buf
->priv
;
198 if (obj
->export_dma_buf
== dma_buf
) {
199 /* drop the reference on the export fd holds */
200 obj
->export_dma_buf
= NULL
;
201 drm_gem_object_unreference_unlocked(obj
);
205 static void *drm_gem_dmabuf_vmap(struct dma_buf
*dma_buf
)
207 struct drm_gem_object
*obj
= dma_buf
->priv
;
208 struct drm_device
*dev
= obj
->dev
;
210 return dev
->driver
->gem_prime_vmap(obj
);
213 static void drm_gem_dmabuf_vunmap(struct dma_buf
*dma_buf
, void *vaddr
)
215 struct drm_gem_object
*obj
= dma_buf
->priv
;
216 struct drm_device
*dev
= obj
->dev
;
218 dev
->driver
->gem_prime_vunmap(obj
, vaddr
);
221 static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf
*dma_buf
,
222 unsigned long page_num
)
227 static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf
*dma_buf
,
228 unsigned long page_num
, void *addr
)
232 static void *drm_gem_dmabuf_kmap(struct dma_buf
*dma_buf
,
233 unsigned long page_num
)
238 static void drm_gem_dmabuf_kunmap(struct dma_buf
*dma_buf
,
239 unsigned long page_num
, void *addr
)
244 static int drm_gem_dmabuf_mmap(struct dma_buf
*dma_buf
,
245 struct vm_area_struct
*vma
)
250 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops
= {
251 .attach
= drm_gem_map_attach
,
252 .detach
= drm_gem_map_detach
,
253 .map_dma_buf
= drm_gem_map_dma_buf
,
254 .unmap_dma_buf
= drm_gem_unmap_dma_buf
,
255 .release
= drm_gem_dmabuf_release
,
256 .kmap
= drm_gem_dmabuf_kmap
,
257 .kmap_atomic
= drm_gem_dmabuf_kmap_atomic
,
258 .kunmap
= drm_gem_dmabuf_kunmap
,
259 .kunmap_atomic
= drm_gem_dmabuf_kunmap_atomic
,
260 .mmap
= drm_gem_dmabuf_mmap
,
261 .vmap
= drm_gem_dmabuf_vmap
,
262 .vunmap
= drm_gem_dmabuf_vunmap
,
268 * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
269 * simpler APIs by using the helper functions @drm_gem_prime_export and
270 * @drm_gem_prime_import. These functions implement dma-buf support in terms of
271 * five lower-level driver callbacks:
275 * - @gem_prime_pin (optional): prepare a GEM object for exporting
277 * - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
279 * - @gem_prime_vmap: vmap a buffer exported by your driver
281 * - @gem_prime_vunmap: vunmap a buffer exported by your driver
285 * - @gem_prime_import_sg_table (import): produce a GEM object from another
286 * driver's scatter/gather table
289 struct dma_buf
*drm_gem_prime_export(struct drm_device
*dev
,
290 struct drm_gem_object
*obj
, int flags
)
292 return dma_buf_export(obj
, &drm_gem_prime_dmabuf_ops
, obj
->size
, flags
);
294 EXPORT_SYMBOL(drm_gem_prime_export
);
296 int drm_gem_prime_handle_to_fd(struct drm_device
*dev
,
297 struct drm_file
*file_priv
, uint32_t handle
, uint32_t flags
,
300 struct drm_gem_object
*obj
;
303 struct dma_buf
*dmabuf
;
305 obj
= drm_gem_object_lookup(dev
, file_priv
, handle
);
309 mutex_lock(&file_priv
->prime
.lock
);
310 /* re-export the original imported object */
311 if (obj
->import_attach
) {
312 dmabuf
= obj
->import_attach
->dmabuf
;
316 if (obj
->export_dma_buf
) {
317 dmabuf
= obj
->export_dma_buf
;
321 buf
= dev
->driver
->gem_prime_export(dev
, obj
, flags
);
323 /* normally the created dma-buf takes ownership of the ref,
324 * but if that fails then drop the ref
329 obj
->export_dma_buf
= buf
;
331 /* if we've exported this buffer the cheat and add it to the import list
332 * so we get the correct handle back
334 ret
= drm_prime_add_buf_handle(&file_priv
->prime
,
335 obj
->export_dma_buf
, handle
);
337 goto fail_put_dmabuf
;
339 ret
= dma_buf_fd(buf
, flags
);
344 mutex_unlock(&file_priv
->prime
.lock
);
349 ret
= dma_buf_fd(dmabuf
, flags
);
357 drm_prime_remove_buf_handle_locked(&file_priv
->prime
, buf
);
359 /* clear NOT to be checked when releasing dma_buf */
360 obj
->export_dma_buf
= NULL
;
363 drm_gem_object_unreference_unlocked(obj
);
364 mutex_unlock(&file_priv
->prime
.lock
);
367 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd
);
369 struct drm_gem_object
*drm_gem_prime_import(struct drm_device
*dev
,
370 struct dma_buf
*dma_buf
)
372 struct dma_buf_attachment
*attach
;
373 struct sg_table
*sgt
;
374 struct drm_gem_object
*obj
;
377 if (!dev
->driver
->gem_prime_import_sg_table
)
378 return ERR_PTR(-EINVAL
);
380 if (dma_buf
->ops
== &drm_gem_prime_dmabuf_ops
) {
382 if (obj
->dev
== dev
) {
384 * Importing dmabuf exported from out own gem increases
385 * refcount on gem itself instead of f_count of dmabuf.
387 drm_gem_object_reference(obj
);
392 attach
= dma_buf_attach(dma_buf
, dev
->dev
);
394 return ERR_CAST(attach
);
396 get_dma_buf(dma_buf
);
398 sgt
= dma_buf_map_attachment(attach
, DMA_BIDIRECTIONAL
);
399 if (IS_ERR_OR_NULL(sgt
)) {
404 obj
= dev
->driver
->gem_prime_import_sg_table(dev
, dma_buf
->size
, sgt
);
410 obj
->import_attach
= attach
;
415 dma_buf_unmap_attachment(attach
, sgt
, DMA_BIDIRECTIONAL
);
417 dma_buf_detach(dma_buf
, attach
);
418 dma_buf_put(dma_buf
);
422 EXPORT_SYMBOL(drm_gem_prime_import
);
424 int drm_gem_prime_fd_to_handle(struct drm_device
*dev
,
425 struct drm_file
*file_priv
, int prime_fd
, uint32_t *handle
)
427 struct dma_buf
*dma_buf
;
428 struct drm_gem_object
*obj
;
431 dma_buf
= dma_buf_get(prime_fd
);
433 return PTR_ERR(dma_buf
);
435 mutex_lock(&file_priv
->prime
.lock
);
437 ret
= drm_prime_lookup_buf_handle(&file_priv
->prime
,
444 /* never seen this one, need to import */
445 obj
= dev
->driver
->gem_prime_import(dev
, dma_buf
);
451 ret
= drm_gem_handle_create(file_priv
, obj
, handle
);
452 drm_gem_object_unreference_unlocked(obj
);
456 ret
= drm_prime_add_buf_handle(&file_priv
->prime
,
461 mutex_unlock(&file_priv
->prime
.lock
);
463 dma_buf_put(dma_buf
);
468 /* hmm, if driver attached, we are relying on the free-object path
469 * to detach.. which seems ok..
471 drm_gem_object_handle_unreference_unlocked(obj
);
473 dma_buf_put(dma_buf
);
474 mutex_unlock(&file_priv
->prime
.lock
);
477 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle
);
479 int drm_prime_handle_to_fd_ioctl(struct drm_device
*dev
, void *data
,
480 struct drm_file
*file_priv
)
482 struct drm_prime_handle
*args
= data
;
485 if (!drm_core_check_feature(dev
, DRIVER_PRIME
))
488 if (!dev
->driver
->prime_handle_to_fd
)
491 /* check flags are valid */
492 if (args
->flags
& ~DRM_CLOEXEC
)
495 /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
496 flags
= args
->flags
& DRM_CLOEXEC
;
498 return dev
->driver
->prime_handle_to_fd(dev
, file_priv
,
499 args
->handle
, flags
, &args
->fd
);
502 int drm_prime_fd_to_handle_ioctl(struct drm_device
*dev
, void *data
,
503 struct drm_file
*file_priv
)
505 struct drm_prime_handle
*args
= data
;
507 if (!drm_core_check_feature(dev
, DRIVER_PRIME
))
510 if (!dev
->driver
->prime_fd_to_handle
)
513 return dev
->driver
->prime_fd_to_handle(dev
, file_priv
,
514 args
->fd
, &args
->handle
);
518 * drm_prime_pages_to_sg
520 * this helper creates an sg table object from a set of pages
521 * the driver is responsible for mapping the pages into the
522 * importers address space
524 struct sg_table
*drm_prime_pages_to_sg(struct page
**pages
, int nr_pages
)
526 struct sg_table
*sg
= NULL
;
529 sg
= kmalloc(sizeof(struct sg_table
), GFP_KERNEL
);
535 ret
= sg_alloc_table_from_pages(sg
, pages
, nr_pages
, 0,
536 nr_pages
<< PAGE_SHIFT
, GFP_KERNEL
);
545 EXPORT_SYMBOL(drm_prime_pages_to_sg
);
547 /* export an sg table into an array of pages and addresses
548 this is currently required by the TTM driver in order to do correct fault
550 int drm_prime_sg_to_page_addr_arrays(struct sg_table
*sgt
, struct page
**pages
,
551 dma_addr_t
*addrs
, int max_pages
)
554 struct scatterlist
*sg
;
561 for_each_sg(sgt
->sgl
, sg
, sgt
->nents
, count
) {
565 addr
= sg_dma_address(sg
);
568 if (WARN_ON(pg_index
>= max_pages
))
570 pages
[pg_index
] = page
;
572 addrs
[pg_index
] = addr
;
582 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays
);
583 /* helper function to cleanup a GEM/prime object */
584 void drm_prime_gem_destroy(struct drm_gem_object
*obj
, struct sg_table
*sg
)
586 struct dma_buf_attachment
*attach
;
587 struct dma_buf
*dma_buf
;
588 attach
= obj
->import_attach
;
590 dma_buf_unmap_attachment(attach
, sg
, DMA_BIDIRECTIONAL
);
591 dma_buf
= attach
->dmabuf
;
592 dma_buf_detach(attach
->dmabuf
, attach
);
593 /* remove the reference */
594 dma_buf_put(dma_buf
);
596 EXPORT_SYMBOL(drm_prime_gem_destroy
);
598 void drm_prime_init_file_private(struct drm_prime_file_private
*prime_fpriv
)
600 INIT_LIST_HEAD(&prime_fpriv
->head
);
601 mutex_init(&prime_fpriv
->lock
);
603 EXPORT_SYMBOL(drm_prime_init_file_private
);
605 void drm_prime_destroy_file_private(struct drm_prime_file_private
*prime_fpriv
)
607 /* by now drm_gem_release should've made sure the list is empty */
608 WARN_ON(!list_empty(&prime_fpriv
->head
));
610 EXPORT_SYMBOL(drm_prime_destroy_file_private
);
612 int drm_prime_lookup_buf_handle(struct drm_prime_file_private
*prime_fpriv
, struct dma_buf
*dma_buf
, uint32_t *handle
)
614 struct drm_prime_member
*member
;
616 list_for_each_entry(member
, &prime_fpriv
->head
, entry
) {
617 if (member
->dma_buf
== dma_buf
) {
618 *handle
= member
->handle
;
624 EXPORT_SYMBOL(drm_prime_lookup_buf_handle
);
626 void drm_prime_remove_buf_handle(struct drm_prime_file_private
*prime_fpriv
, struct dma_buf
*dma_buf
)
628 mutex_lock(&prime_fpriv
->lock
);
629 drm_prime_remove_buf_handle_locked(prime_fpriv
, dma_buf
);
630 mutex_unlock(&prime_fpriv
->lock
);
632 EXPORT_SYMBOL(drm_prime_remove_buf_handle
);