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 int drm_gem_map_attach(struct dma_buf
*dma_buf
,
68 struct device
*target_dev
,
69 struct dma_buf_attachment
*attach
)
71 struct drm_gem_object
*obj
= dma_buf
->priv
;
72 struct drm_device
*dev
= obj
->dev
;
74 if (!dev
->driver
->gem_prime_pin
)
77 return dev
->driver
->gem_prime_pin(obj
);
80 static void drm_gem_map_detach(struct dma_buf
*dma_buf
,
81 struct dma_buf_attachment
*attach
)
83 struct drm_gem_object
*obj
= dma_buf
->priv
;
84 struct drm_device
*dev
= obj
->dev
;
86 if (dev
->driver
->gem_prime_unpin
)
87 dev
->driver
->gem_prime_unpin(obj
);
90 static struct sg_table
*drm_gem_map_dma_buf(struct dma_buf_attachment
*attach
,
91 enum dma_data_direction dir
)
93 struct drm_gem_object
*obj
= attach
->dmabuf
->priv
;
96 mutex_lock(&obj
->dev
->struct_mutex
);
98 sgt
= obj
->dev
->driver
->gem_prime_get_sg_table(obj
);
100 if (!IS_ERR_OR_NULL(sgt
))
101 dma_map_sg(attach
->dev
, sgt
->sgl
, sgt
->nents
, dir
);
103 mutex_unlock(&obj
->dev
->struct_mutex
);
107 static void drm_gem_unmap_dma_buf(struct dma_buf_attachment
*attach
,
108 struct sg_table
*sgt
, enum dma_data_direction dir
)
110 dma_unmap_sg(attach
->dev
, sgt
->sgl
, sgt
->nents
, dir
);
115 static void drm_gem_dmabuf_release(struct dma_buf
*dma_buf
)
117 struct drm_gem_object
*obj
= dma_buf
->priv
;
119 if (obj
->export_dma_buf
== dma_buf
) {
120 /* drop the reference on the export fd holds */
121 obj
->export_dma_buf
= NULL
;
122 drm_gem_object_unreference_unlocked(obj
);
126 static void *drm_gem_dmabuf_vmap(struct dma_buf
*dma_buf
)
128 struct drm_gem_object
*obj
= dma_buf
->priv
;
129 struct drm_device
*dev
= obj
->dev
;
131 return dev
->driver
->gem_prime_vmap(obj
);
134 static void drm_gem_dmabuf_vunmap(struct dma_buf
*dma_buf
, void *vaddr
)
136 struct drm_gem_object
*obj
= dma_buf
->priv
;
137 struct drm_device
*dev
= obj
->dev
;
139 dev
->driver
->gem_prime_vunmap(obj
, vaddr
);
142 static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf
*dma_buf
,
143 unsigned long page_num
)
148 static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf
*dma_buf
,
149 unsigned long page_num
, void *addr
)
153 static void *drm_gem_dmabuf_kmap(struct dma_buf
*dma_buf
,
154 unsigned long page_num
)
159 static void drm_gem_dmabuf_kunmap(struct dma_buf
*dma_buf
,
160 unsigned long page_num
, void *addr
)
165 static int drm_gem_dmabuf_mmap(struct dma_buf
*dma_buf
,
166 struct vm_area_struct
*vma
)
171 static const struct dma_buf_ops drm_gem_prime_dmabuf_ops
= {
172 .attach
= drm_gem_map_attach
,
173 .detach
= drm_gem_map_detach
,
174 .map_dma_buf
= drm_gem_map_dma_buf
,
175 .unmap_dma_buf
= drm_gem_unmap_dma_buf
,
176 .release
= drm_gem_dmabuf_release
,
177 .kmap
= drm_gem_dmabuf_kmap
,
178 .kmap_atomic
= drm_gem_dmabuf_kmap_atomic
,
179 .kunmap
= drm_gem_dmabuf_kunmap
,
180 .kunmap_atomic
= drm_gem_dmabuf_kunmap_atomic
,
181 .mmap
= drm_gem_dmabuf_mmap
,
182 .vmap
= drm_gem_dmabuf_vmap
,
183 .vunmap
= drm_gem_dmabuf_vunmap
,
189 * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
190 * simpler APIs by using the helper functions @drm_gem_prime_export and
191 * @drm_gem_prime_import. These functions implement dma-buf support in terms of
192 * five lower-level driver callbacks:
196 * - @gem_prime_pin (optional): prepare a GEM object for exporting
198 * - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
200 * - @gem_prime_vmap: vmap a buffer exported by your driver
202 * - @gem_prime_vunmap: vunmap a buffer exported by your driver
206 * - @gem_prime_import_sg_table (import): produce a GEM object from another
207 * driver's scatter/gather table
210 struct dma_buf
*drm_gem_prime_export(struct drm_device
*dev
,
211 struct drm_gem_object
*obj
, int flags
)
213 return dma_buf_export(obj
, &drm_gem_prime_dmabuf_ops
, obj
->size
,
216 EXPORT_SYMBOL(drm_gem_prime_export
);
218 int drm_gem_prime_handle_to_fd(struct drm_device
*dev
,
219 struct drm_file
*file_priv
, uint32_t handle
, uint32_t flags
,
222 struct drm_gem_object
*obj
;
225 struct dma_buf
*dmabuf
;
227 obj
= drm_gem_object_lookup(dev
, file_priv
, handle
);
231 mutex_lock(&file_priv
->prime
.lock
);
232 /* re-export the original imported object */
233 if (obj
->import_attach
) {
234 dmabuf
= obj
->import_attach
->dmabuf
;
238 if (obj
->export_dma_buf
) {
239 dmabuf
= obj
->export_dma_buf
;
243 buf
= dev
->driver
->gem_prime_export(dev
, obj
, flags
);
245 /* normally the created dma-buf takes ownership of the ref,
246 * but if that fails then drop the ref
251 obj
->export_dma_buf
= buf
;
253 /* if we've exported this buffer the cheat and add it to the import list
254 * so we get the correct handle back
256 ret
= drm_prime_add_buf_handle(&file_priv
->prime
,
257 obj
->export_dma_buf
, handle
);
261 *prime_fd
= dma_buf_fd(buf
, flags
);
262 mutex_unlock(&file_priv
->prime
.lock
);
267 *prime_fd
= dma_buf_fd(dmabuf
, flags
);
269 drm_gem_object_unreference_unlocked(obj
);
270 mutex_unlock(&file_priv
->prime
.lock
);
273 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd
);
275 struct drm_gem_object
*drm_gem_prime_import(struct drm_device
*dev
,
276 struct dma_buf
*dma_buf
)
278 struct dma_buf_attachment
*attach
;
279 struct sg_table
*sgt
;
280 struct drm_gem_object
*obj
;
283 if (!dev
->driver
->gem_prime_import_sg_table
)
284 return ERR_PTR(-EINVAL
);
286 if (dma_buf
->ops
== &drm_gem_prime_dmabuf_ops
) {
288 if (obj
->dev
== dev
) {
290 * Importing dmabuf exported from out own gem increases
291 * refcount on gem itself instead of f_count of dmabuf.
293 drm_gem_object_reference(obj
);
298 attach
= dma_buf_attach(dma_buf
, dev
->dev
);
300 return ERR_CAST(attach
);
302 get_dma_buf(dma_buf
);
304 sgt
= dma_buf_map_attachment(attach
, DMA_BIDIRECTIONAL
);
305 if (IS_ERR_OR_NULL(sgt
)) {
310 obj
= dev
->driver
->gem_prime_import_sg_table(dev
, dma_buf
->size
, sgt
);
316 obj
->import_attach
= attach
;
321 dma_buf_unmap_attachment(attach
, sgt
, DMA_BIDIRECTIONAL
);
323 dma_buf_detach(dma_buf
, attach
);
324 dma_buf_put(dma_buf
);
328 EXPORT_SYMBOL(drm_gem_prime_import
);
330 int drm_gem_prime_fd_to_handle(struct drm_device
*dev
,
331 struct drm_file
*file_priv
, int prime_fd
, uint32_t *handle
)
333 struct dma_buf
*dma_buf
;
334 struct drm_gem_object
*obj
;
337 dma_buf
= dma_buf_get(prime_fd
);
339 return PTR_ERR(dma_buf
);
341 mutex_lock(&file_priv
->prime
.lock
);
343 ret
= drm_prime_lookup_buf_handle(&file_priv
->prime
,
350 /* never seen this one, need to import */
351 obj
= dev
->driver
->gem_prime_import(dev
, dma_buf
);
357 ret
= drm_gem_handle_create(file_priv
, obj
, handle
);
358 drm_gem_object_unreference_unlocked(obj
);
362 ret
= drm_prime_add_buf_handle(&file_priv
->prime
,
367 mutex_unlock(&file_priv
->prime
.lock
);
369 dma_buf_put(dma_buf
);
374 /* hmm, if driver attached, we are relying on the free-object path
375 * to detach.. which seems ok..
377 drm_gem_object_handle_unreference_unlocked(obj
);
379 dma_buf_put(dma_buf
);
380 mutex_unlock(&file_priv
->prime
.lock
);
383 EXPORT_SYMBOL(drm_gem_prime_fd_to_handle
);
385 int drm_prime_handle_to_fd_ioctl(struct drm_device
*dev
, void *data
,
386 struct drm_file
*file_priv
)
388 struct drm_prime_handle
*args
= data
;
391 if (!drm_core_check_feature(dev
, DRIVER_PRIME
))
394 if (!dev
->driver
->prime_handle_to_fd
)
397 /* check flags are valid */
398 if (args
->flags
& ~DRM_CLOEXEC
)
401 /* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
402 flags
= args
->flags
& DRM_CLOEXEC
;
404 return dev
->driver
->prime_handle_to_fd(dev
, file_priv
,
405 args
->handle
, flags
, &args
->fd
);
408 int drm_prime_fd_to_handle_ioctl(struct drm_device
*dev
, void *data
,
409 struct drm_file
*file_priv
)
411 struct drm_prime_handle
*args
= data
;
413 if (!drm_core_check_feature(dev
, DRIVER_PRIME
))
416 if (!dev
->driver
->prime_fd_to_handle
)
419 return dev
->driver
->prime_fd_to_handle(dev
, file_priv
,
420 args
->fd
, &args
->handle
);
424 * drm_prime_pages_to_sg
426 * this helper creates an sg table object from a set of pages
427 * the driver is responsible for mapping the pages into the
428 * importers address space
430 struct sg_table
*drm_prime_pages_to_sg(struct page
**pages
, int nr_pages
)
432 struct sg_table
*sg
= NULL
;
435 sg
= kmalloc(sizeof(struct sg_table
), GFP_KERNEL
);
439 ret
= sg_alloc_table_from_pages(sg
, pages
, nr_pages
, 0,
440 nr_pages
<< PAGE_SHIFT
, GFP_KERNEL
);
449 EXPORT_SYMBOL(drm_prime_pages_to_sg
);
451 /* export an sg table into an array of pages and addresses
452 this is currently required by the TTM driver in order to do correct fault
454 int drm_prime_sg_to_page_addr_arrays(struct sg_table
*sgt
, struct page
**pages
,
455 dma_addr_t
*addrs
, int max_pages
)
458 struct scatterlist
*sg
;
465 for_each_sg(sgt
->sgl
, sg
, sgt
->nents
, count
) {
469 addr
= sg_dma_address(sg
);
472 if (WARN_ON(pg_index
>= max_pages
))
474 pages
[pg_index
] = page
;
476 addrs
[pg_index
] = addr
;
486 EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays
);
487 /* helper function to cleanup a GEM/prime object */
488 void drm_prime_gem_destroy(struct drm_gem_object
*obj
, struct sg_table
*sg
)
490 struct dma_buf_attachment
*attach
;
491 struct dma_buf
*dma_buf
;
492 attach
= obj
->import_attach
;
494 dma_buf_unmap_attachment(attach
, sg
, DMA_BIDIRECTIONAL
);
495 dma_buf
= attach
->dmabuf
;
496 dma_buf_detach(attach
->dmabuf
, attach
);
497 /* remove the reference */
498 dma_buf_put(dma_buf
);
500 EXPORT_SYMBOL(drm_prime_gem_destroy
);
502 void drm_prime_init_file_private(struct drm_prime_file_private
*prime_fpriv
)
504 INIT_LIST_HEAD(&prime_fpriv
->head
);
505 mutex_init(&prime_fpriv
->lock
);
507 EXPORT_SYMBOL(drm_prime_init_file_private
);
509 void drm_prime_destroy_file_private(struct drm_prime_file_private
*prime_fpriv
)
511 /* by now drm_gem_release should've made sure the list is empty */
512 WARN_ON(!list_empty(&prime_fpriv
->head
));
514 EXPORT_SYMBOL(drm_prime_destroy_file_private
);
516 static int drm_prime_add_buf_handle(struct drm_prime_file_private
*prime_fpriv
, struct dma_buf
*dma_buf
, uint32_t handle
)
518 struct drm_prime_member
*member
;
520 member
= kmalloc(sizeof(*member
), GFP_KERNEL
);
524 get_dma_buf(dma_buf
);
525 member
->dma_buf
= dma_buf
;
526 member
->handle
= handle
;
527 list_add(&member
->entry
, &prime_fpriv
->head
);
531 int drm_prime_lookup_buf_handle(struct drm_prime_file_private
*prime_fpriv
, struct dma_buf
*dma_buf
, uint32_t *handle
)
533 struct drm_prime_member
*member
;
535 list_for_each_entry(member
, &prime_fpriv
->head
, entry
) {
536 if (member
->dma_buf
== dma_buf
) {
537 *handle
= member
->handle
;
543 EXPORT_SYMBOL(drm_prime_lookup_buf_handle
);
545 void drm_prime_remove_buf_handle(struct drm_prime_file_private
*prime_fpriv
, struct dma_buf
*dma_buf
)
547 struct drm_prime_member
*member
, *safe
;
549 mutex_lock(&prime_fpriv
->lock
);
550 list_for_each_entry_safe(member
, safe
, &prime_fpriv
->head
, entry
) {
551 if (member
->dma_buf
== dma_buf
) {
552 dma_buf_put(dma_buf
);
553 list_del(&member
->entry
);
557 mutex_unlock(&prime_fpriv
->lock
);
559 EXPORT_SYMBOL(drm_prime_remove_buf_handle
);