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1/*
2 * Copyright © 2012 Red Hat
3 *
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:
10 *
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
13 * Software.
14 *
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
21 * IN THE SOFTWARE.
22 *
23 * Authors:
24 * Dave Airlie <airlied@redhat.com>
25 * Rob Clark <rob.clark@linaro.org>
26 *
27 */
28
29#include <linux/export.h>
30#include <linux/dma-buf.h>
31#include <linux/rbtree.h>
32#include <linux/module.h>
33
34#include <drm/drm.h>
35#include <drm/drm_drv.h>
36#include <drm/drm_file.h>
37#include <drm/drm_framebuffer.h>
38#include <drm/drm_gem.h>
39#include <drm/drm_prime.h>
40
41#include "drm_internal.h"
42
43MODULE_IMPORT_NS(DMA_BUF);
44
45/**
46 * DOC: overview and lifetime rules
47 *
48 * Similar to GEM global names, PRIME file descriptors are also used to share
49 * buffer objects across processes. They offer additional security: as file
50 * descriptors must be explicitly sent over UNIX domain sockets to be shared
51 * between applications, they can't be guessed like the globally unique GEM
52 * names.
53 *
54 * Drivers that support the PRIME API implement the drm_gem_object_funcs.export
55 * and &drm_driver.gem_prime_import hooks. &dma_buf_ops implementations for
56 * drivers are all individually exported for drivers which need to overwrite
57 * or reimplement some of them.
58 *
59 * Reference Counting for GEM Drivers
60 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
61 *
62 * On the export the &dma_buf holds a reference to the exported buffer object,
63 * usually a &drm_gem_object. It takes this reference in the PRIME_HANDLE_TO_FD
64 * IOCTL, when it first calls &drm_gem_object_funcs.export
65 * and stores the exporting GEM object in the &dma_buf.priv field. This
66 * reference needs to be released when the final reference to the &dma_buf
67 * itself is dropped and its &dma_buf_ops.release function is called. For
68 * GEM-based drivers, the &dma_buf should be exported using
69 * drm_gem_dmabuf_export() and then released by drm_gem_dmabuf_release().
70 *
71 * Thus the chain of references always flows in one direction, avoiding loops:
72 * importing GEM object -> dma-buf -> exported GEM bo. A further complication
73 * are the lookup caches for import and export. These are required to guarantee
74 * that any given object will always have only one unique userspace handle. This
75 * is required to allow userspace to detect duplicated imports, since some GEM
76 * drivers do fail command submissions if a given buffer object is listed more
77 * than once. These import and export caches in &drm_prime_file_private only
78 * retain a weak reference, which is cleaned up when the corresponding object is
79 * released.
80 *
81 * Self-importing: If userspace is using PRIME as a replacement for flink then
82 * it will get a fd->handle request for a GEM object that it created. Drivers
83 * should detect this situation and return back the underlying object from the
84 * dma-buf private. For GEM based drivers this is handled in
85 * drm_gem_prime_import() already.
86 */
87
88struct drm_prime_member {
89 struct dma_buf *dma_buf;
90 uint32_t handle;
91
92 struct rb_node dmabuf_rb;
93 struct rb_node handle_rb;
94};
95
96static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
97 struct dma_buf *dma_buf, uint32_t handle)
98{
99 struct drm_prime_member *member;
100 struct rb_node **p, *rb;
101
102 member = kmalloc(sizeof(*member), GFP_KERNEL);
103 if (!member)
104 return -ENOMEM;
105
106 get_dma_buf(dma_buf);
107 member->dma_buf = dma_buf;
108 member->handle = handle;
109
110 rb = NULL;
111 p = &prime_fpriv->dmabufs.rb_node;
112 while (*p) {
113 struct drm_prime_member *pos;
114
115 rb = *p;
116 pos = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
117 if (dma_buf > pos->dma_buf)
118 p = &rb->rb_right;
119 else
120 p = &rb->rb_left;
121 }
122 rb_link_node(&member->dmabuf_rb, rb, p);
123 rb_insert_color(&member->dmabuf_rb, &prime_fpriv->dmabufs);
124
125 rb = NULL;
126 p = &prime_fpriv->handles.rb_node;
127 while (*p) {
128 struct drm_prime_member *pos;
129
130 rb = *p;
131 pos = rb_entry(rb, struct drm_prime_member, handle_rb);
132 if (handle > pos->handle)
133 p = &rb->rb_right;
134 else
135 p = &rb->rb_left;
136 }
137 rb_link_node(&member->handle_rb, rb, p);
138 rb_insert_color(&member->handle_rb, &prime_fpriv->handles);
139
140 return 0;
141}
142
143static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
144 uint32_t handle)
145{
146 struct rb_node *rb;
147
148 rb = prime_fpriv->handles.rb_node;
149 while (rb) {
150 struct drm_prime_member *member;
151
152 member = rb_entry(rb, struct drm_prime_member, handle_rb);
153 if (member->handle == handle)
154 return member->dma_buf;
155 else if (member->handle < handle)
156 rb = rb->rb_right;
157 else
158 rb = rb->rb_left;
159 }
160
161 return NULL;
162}
163
164static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
165 struct dma_buf *dma_buf,
166 uint32_t *handle)
167{
168 struct rb_node *rb;
169
170 rb = prime_fpriv->dmabufs.rb_node;
171 while (rb) {
172 struct drm_prime_member *member;
173
174 member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
175 if (member->dma_buf == dma_buf) {
176 *handle = member->handle;
177 return 0;
178 } else if (member->dma_buf < dma_buf) {
179 rb = rb->rb_right;
180 } else {
181 rb = rb->rb_left;
182 }
183 }
184
185 return -ENOENT;
186}
187
188void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv,
189 uint32_t handle)
190{
191 struct rb_node *rb;
192
193 mutex_lock(&prime_fpriv->lock);
194
195 rb = prime_fpriv->handles.rb_node;
196 while (rb) {
197 struct drm_prime_member *member;
198
199 member = rb_entry(rb, struct drm_prime_member, handle_rb);
200 if (member->handle == handle) {
201 rb_erase(&member->handle_rb, &prime_fpriv->handles);
202 rb_erase(&member->dmabuf_rb, &prime_fpriv->dmabufs);
203
204 dma_buf_put(member->dma_buf);
205 kfree(member);
206 break;
207 } else if (member->handle < handle) {
208 rb = rb->rb_right;
209 } else {
210 rb = rb->rb_left;
211 }
212 }
213
214 mutex_unlock(&prime_fpriv->lock);
215}
216
217void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
218{
219 mutex_init(&prime_fpriv->lock);
220 prime_fpriv->dmabufs = RB_ROOT;
221 prime_fpriv->handles = RB_ROOT;
222}
223
224void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
225{
226 /* by now drm_gem_release should've made sure the list is empty */
227 WARN_ON(!RB_EMPTY_ROOT(&prime_fpriv->dmabufs));
228}
229
230/**
231 * drm_gem_dmabuf_export - &dma_buf export implementation for GEM
232 * @dev: parent device for the exported dmabuf
233 * @exp_info: the export information used by dma_buf_export()
234 *
235 * This wraps dma_buf_export() for use by generic GEM drivers that are using
236 * drm_gem_dmabuf_release(). In addition to calling dma_buf_export(), we take
237 * a reference to the &drm_device and the exported &drm_gem_object (stored in
238 * &dma_buf_export_info.priv) which is released by drm_gem_dmabuf_release().
239 *
240 * Returns the new dmabuf.
241 */
242struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
243 struct dma_buf_export_info *exp_info)
244{
245 struct drm_gem_object *obj = exp_info->priv;
246 struct dma_buf *dma_buf;
247
248 dma_buf = dma_buf_export(exp_info);
249 if (IS_ERR(dma_buf))
250 return dma_buf;
251
252 drm_dev_get(dev);
253 drm_gem_object_get(obj);
254 dma_buf->file->f_mapping = obj->dev->anon_inode->i_mapping;
255
256 return dma_buf;
257}
258EXPORT_SYMBOL(drm_gem_dmabuf_export);
259
260/**
261 * drm_gem_dmabuf_release - &dma_buf release implementation for GEM
262 * @dma_buf: buffer to be released
263 *
264 * Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
265 * must use this in their &dma_buf_ops structure as the release callback.
266 * drm_gem_dmabuf_release() should be used in conjunction with
267 * drm_gem_dmabuf_export().
268 */
269void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
270{
271 struct drm_gem_object *obj = dma_buf->priv;
272 struct drm_device *dev = obj->dev;
273
274 /* drop the reference on the export fd holds */
275 drm_gem_object_put(obj);
276
277 drm_dev_put(dev);
278}
279EXPORT_SYMBOL(drm_gem_dmabuf_release);
280
281/**
282 * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
283 * @dev: drm_device to import into
284 * @file_priv: drm file-private structure
285 * @prime_fd: fd id of the dma-buf which should be imported
286 * @handle: pointer to storage for the handle of the imported buffer object
287 *
288 * This is the PRIME import function which must be used mandatorily by GEM
289 * drivers to ensure correct lifetime management of the underlying GEM object.
290 * The actual importing of GEM object from the dma-buf is done through the
291 * &drm_driver.gem_prime_import driver callback.
292 *
293 * Returns 0 on success or a negative error code on failure.
294 */
295int drm_gem_prime_fd_to_handle(struct drm_device *dev,
296 struct drm_file *file_priv, int prime_fd,
297 uint32_t *handle)
298{
299 struct dma_buf *dma_buf;
300 struct drm_gem_object *obj;
301 int ret;
302
303 dma_buf = dma_buf_get(prime_fd);
304 if (IS_ERR(dma_buf))
305 return PTR_ERR(dma_buf);
306
307 mutex_lock(&file_priv->prime.lock);
308
309 ret = drm_prime_lookup_buf_handle(&file_priv->prime,
310 dma_buf, handle);
311 if (ret == 0)
312 goto out_put;
313
314 /* never seen this one, need to import */
315 mutex_lock(&dev->object_name_lock);
316 if (dev->driver->gem_prime_import)
317 obj = dev->driver->gem_prime_import(dev, dma_buf);
318 else
319 obj = drm_gem_prime_import(dev, dma_buf);
320 if (IS_ERR(obj)) {
321 ret = PTR_ERR(obj);
322 goto out_unlock;
323 }
324
325 if (obj->dma_buf) {
326 WARN_ON(obj->dma_buf != dma_buf);
327 } else {
328 obj->dma_buf = dma_buf;
329 get_dma_buf(dma_buf);
330 }
331
332 /* _handle_create_tail unconditionally unlocks dev->object_name_lock. */
333 ret = drm_gem_handle_create_tail(file_priv, obj, handle);
334 drm_gem_object_put(obj);
335 if (ret)
336 goto out_put;
337
338 ret = drm_prime_add_buf_handle(&file_priv->prime,
339 dma_buf, *handle);
340 mutex_unlock(&file_priv->prime.lock);
341 if (ret)
342 goto fail;
343
344 dma_buf_put(dma_buf);
345
346 return 0;
347
348fail:
349 /* hmm, if driver attached, we are relying on the free-object path
350 * to detach.. which seems ok..
351 */
352 drm_gem_handle_delete(file_priv, *handle);
353 dma_buf_put(dma_buf);
354 return ret;
355
356out_unlock:
357 mutex_unlock(&dev->object_name_lock);
358out_put:
359 mutex_unlock(&file_priv->prime.lock);
360 dma_buf_put(dma_buf);
361 return ret;
362}
363EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
364
365int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
366 struct drm_file *file_priv)
367{
368 struct drm_prime_handle *args = data;
369
370 if (dev->driver->prime_fd_to_handle) {
371 return dev->driver->prime_fd_to_handle(dev, file_priv, args->fd,
372 &args->handle);
373 }
374
375 return drm_gem_prime_fd_to_handle(dev, file_priv, args->fd, &args->handle);
376}
377
378static struct dma_buf *export_and_register_object(struct drm_device *dev,
379 struct drm_gem_object *obj,
380 uint32_t flags)
381{
382 struct dma_buf *dmabuf;
383
384 /* prevent races with concurrent gem_close. */
385 if (obj->handle_count == 0) {
386 dmabuf = ERR_PTR(-ENOENT);
387 return dmabuf;
388 }
389
390 if (obj->funcs && obj->funcs->export)
391 dmabuf = obj->funcs->export(obj, flags);
392 else
393 dmabuf = drm_gem_prime_export(obj, flags);
394 if (IS_ERR(dmabuf)) {
395 /* normally the created dma-buf takes ownership of the ref,
396 * but if that fails then drop the ref
397 */
398 return dmabuf;
399 }
400
401 /*
402 * Note that callers do not need to clean up the export cache
403 * since the check for obj->handle_count guarantees that someone
404 * will clean it up.
405 */
406 obj->dma_buf = dmabuf;
407 get_dma_buf(obj->dma_buf);
408
409 return dmabuf;
410}
411
412/**
413 * drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
414 * @dev: dev to export the buffer from
415 * @file_priv: drm file-private structure
416 * @handle: buffer handle to export
417 * @flags: flags like DRM_CLOEXEC
418 * @prime_fd: pointer to storage for the fd id of the create dma-buf
419 *
420 * This is the PRIME export function which must be used mandatorily by GEM
421 * drivers to ensure correct lifetime management of the underlying GEM object.
422 * The actual exporting from GEM object to a dma-buf is done through the
423 * &drm_gem_object_funcs.export callback.
424 */
425int drm_gem_prime_handle_to_fd(struct drm_device *dev,
426 struct drm_file *file_priv, uint32_t handle,
427 uint32_t flags,
428 int *prime_fd)
429{
430 struct drm_gem_object *obj;
431 int ret = 0;
432 struct dma_buf *dmabuf;
433
434 mutex_lock(&file_priv->prime.lock);
435 obj = drm_gem_object_lookup(file_priv, handle);
436 if (!obj) {
437 ret = -ENOENT;
438 goto out_unlock;
439 }
440
441 dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
442 if (dmabuf) {
443 get_dma_buf(dmabuf);
444 goto out_have_handle;
445 }
446
447 mutex_lock(&dev->object_name_lock);
448 /* re-export the original imported object */
449 if (obj->import_attach) {
450 dmabuf = obj->import_attach->dmabuf;
451 get_dma_buf(dmabuf);
452 goto out_have_obj;
453 }
454
455 if (obj->dma_buf) {
456 get_dma_buf(obj->dma_buf);
457 dmabuf = obj->dma_buf;
458 goto out_have_obj;
459 }
460
461 dmabuf = export_and_register_object(dev, obj, flags);
462 if (IS_ERR(dmabuf)) {
463 /* normally the created dma-buf takes ownership of the ref,
464 * but if that fails then drop the ref
465 */
466 ret = PTR_ERR(dmabuf);
467 mutex_unlock(&dev->object_name_lock);
468 goto out;
469 }
470
471out_have_obj:
472 /*
473 * If we've exported this buffer then cheat and add it to the import list
474 * so we get the correct handle back. We must do this under the
475 * protection of dev->object_name_lock to ensure that a racing gem close
476 * ioctl doesn't miss to remove this buffer handle from the cache.
477 */
478 ret = drm_prime_add_buf_handle(&file_priv->prime,
479 dmabuf, handle);
480 mutex_unlock(&dev->object_name_lock);
481 if (ret)
482 goto fail_put_dmabuf;
483
484out_have_handle:
485 ret = dma_buf_fd(dmabuf, flags);
486 /*
487 * We must _not_ remove the buffer from the handle cache since the newly
488 * created dma buf is already linked in the global obj->dma_buf pointer,
489 * and that is invariant as long as a userspace gem handle exists.
490 * Closing the handle will clean out the cache anyway, so we don't leak.
491 */
492 if (ret < 0) {
493 goto fail_put_dmabuf;
494 } else {
495 *prime_fd = ret;
496 ret = 0;
497 }
498
499 goto out;
500
501fail_put_dmabuf:
502 dma_buf_put(dmabuf);
503out:
504 drm_gem_object_put(obj);
505out_unlock:
506 mutex_unlock(&file_priv->prime.lock);
507
508 return ret;
509}
510EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
511
512int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
513 struct drm_file *file_priv)
514{
515 struct drm_prime_handle *args = data;
516
517 /* check flags are valid */
518 if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR))
519 return -EINVAL;
520
521 if (dev->driver->prime_handle_to_fd) {
522 return dev->driver->prime_handle_to_fd(dev, file_priv,
523 args->handle, args->flags,
524 &args->fd);
525 }
526 return drm_gem_prime_handle_to_fd(dev, file_priv, args->handle,
527 args->flags, &args->fd);
528}
529
530/**
531 * DOC: PRIME Helpers
532 *
533 * Drivers can implement &drm_gem_object_funcs.export and
534 * &drm_driver.gem_prime_import in terms of simpler APIs by using the helper
535 * functions drm_gem_prime_export() and drm_gem_prime_import(). These functions
536 * implement dma-buf support in terms of some lower-level helpers, which are
537 * again exported for drivers to use individually:
538 *
539 * Exporting buffers
540 * ~~~~~~~~~~~~~~~~~
541 *
542 * Optional pinning of buffers is handled at dma-buf attach and detach time in
543 * drm_gem_map_attach() and drm_gem_map_detach(). Backing storage itself is
544 * handled by drm_gem_map_dma_buf() and drm_gem_unmap_dma_buf(), which relies on
545 * &drm_gem_object_funcs.get_sg_table. If &drm_gem_object_funcs.get_sg_table is
546 * unimplemented, exports into another device are rejected.
547 *
548 * For kernel-internal access there's drm_gem_dmabuf_vmap() and
549 * drm_gem_dmabuf_vunmap(). Userspace mmap support is provided by
550 * drm_gem_dmabuf_mmap().
551 *
552 * Note that these export helpers can only be used if the underlying backing
553 * storage is fully coherent and either permanently pinned, or it is safe to pin
554 * it indefinitely.
555 *
556 * FIXME: The underlying helper functions are named rather inconsistently.
557 *
558 * Importing buffers
559 * ~~~~~~~~~~~~~~~~~
560 *
561 * Importing dma-bufs using drm_gem_prime_import() relies on
562 * &drm_driver.gem_prime_import_sg_table.
563 *
564 * Note that similarly to the export helpers this permanently pins the
565 * underlying backing storage. Which is ok for scanout, but is not the best
566 * option for sharing lots of buffers for rendering.
567 */
568
569/**
570 * drm_gem_map_attach - dma_buf attach implementation for GEM
571 * @dma_buf: buffer to attach device to
572 * @attach: buffer attachment data
573 *
574 * Calls &drm_gem_object_funcs.pin for device specific handling. This can be
575 * used as the &dma_buf_ops.attach callback. Must be used together with
576 * drm_gem_map_detach().
577 *
578 * Returns 0 on success, negative error code on failure.
579 */
580int drm_gem_map_attach(struct dma_buf *dma_buf,
581 struct dma_buf_attachment *attach)
582{
583 struct drm_gem_object *obj = dma_buf->priv;
584
585 /*
586 * drm_gem_map_dma_buf() requires obj->get_sg_table(), but drivers
587 * that implement their own ->map_dma_buf() do not.
588 */
589 if (dma_buf->ops->map_dma_buf == drm_gem_map_dma_buf &&
590 !obj->funcs->get_sg_table)
591 return -ENOSYS;
592
593 return drm_gem_pin(obj);
594}
595EXPORT_SYMBOL(drm_gem_map_attach);
596
597/**
598 * drm_gem_map_detach - dma_buf detach implementation for GEM
599 * @dma_buf: buffer to detach from
600 * @attach: attachment to be detached
601 *
602 * Calls &drm_gem_object_funcs.pin for device specific handling. Cleans up
603 * &dma_buf_attachment from drm_gem_map_attach(). This can be used as the
604 * &dma_buf_ops.detach callback.
605 */
606void drm_gem_map_detach(struct dma_buf *dma_buf,
607 struct dma_buf_attachment *attach)
608{
609 struct drm_gem_object *obj = dma_buf->priv;
610
611 drm_gem_unpin(obj);
612}
613EXPORT_SYMBOL(drm_gem_map_detach);
614
615/**
616 * drm_gem_map_dma_buf - map_dma_buf implementation for GEM
617 * @attach: attachment whose scatterlist is to be returned
618 * @dir: direction of DMA transfer
619 *
620 * Calls &drm_gem_object_funcs.get_sg_table and then maps the scatterlist. This
621 * can be used as the &dma_buf_ops.map_dma_buf callback. Should be used together
622 * with drm_gem_unmap_dma_buf().
623 *
624 * Returns:sg_table containing the scatterlist to be returned; returns ERR_PTR
625 * on error. May return -EINTR if it is interrupted by a signal.
626 */
627struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
628 enum dma_data_direction dir)
629{
630 struct drm_gem_object *obj = attach->dmabuf->priv;
631 struct sg_table *sgt;
632 int ret;
633
634 if (WARN_ON(dir == DMA_NONE))
635 return ERR_PTR(-EINVAL);
636
637 if (WARN_ON(!obj->funcs->get_sg_table))
638 return ERR_PTR(-ENOSYS);
639
640 sgt = obj->funcs->get_sg_table(obj);
641 if (IS_ERR(sgt))
642 return sgt;
643
644 ret = dma_map_sgtable(attach->dev, sgt, dir,
645 DMA_ATTR_SKIP_CPU_SYNC);
646 if (ret) {
647 sg_free_table(sgt);
648 kfree(sgt);
649 sgt = ERR_PTR(ret);
650 }
651
652 return sgt;
653}
654EXPORT_SYMBOL(drm_gem_map_dma_buf);
655
656/**
657 * drm_gem_unmap_dma_buf - unmap_dma_buf implementation for GEM
658 * @attach: attachment to unmap buffer from
659 * @sgt: scatterlist info of the buffer to unmap
660 * @dir: direction of DMA transfer
661 *
662 * This can be used as the &dma_buf_ops.unmap_dma_buf callback.
663 */
664void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
665 struct sg_table *sgt,
666 enum dma_data_direction dir)
667{
668 if (!sgt)
669 return;
670
671 dma_unmap_sgtable(attach->dev, sgt, dir, DMA_ATTR_SKIP_CPU_SYNC);
672 sg_free_table(sgt);
673 kfree(sgt);
674}
675EXPORT_SYMBOL(drm_gem_unmap_dma_buf);
676
677/**
678 * drm_gem_dmabuf_vmap - dma_buf vmap implementation for GEM
679 * @dma_buf: buffer to be mapped
680 * @map: the virtual address of the buffer
681 *
682 * Sets up a kernel virtual mapping. This can be used as the &dma_buf_ops.vmap
683 * callback. Calls into &drm_gem_object_funcs.vmap for device specific handling.
684 * The kernel virtual address is returned in map.
685 *
686 * Returns 0 on success or a negative errno code otherwise.
687 */
688int drm_gem_dmabuf_vmap(struct dma_buf *dma_buf, struct iosys_map *map)
689{
690 struct drm_gem_object *obj = dma_buf->priv;
691
692 return drm_gem_vmap(obj, map);
693}
694EXPORT_SYMBOL(drm_gem_dmabuf_vmap);
695
696/**
697 * drm_gem_dmabuf_vunmap - dma_buf vunmap implementation for GEM
698 * @dma_buf: buffer to be unmapped
699 * @map: the virtual address of the buffer
700 *
701 * Releases a kernel virtual mapping. This can be used as the
702 * &dma_buf_ops.vunmap callback. Calls into &drm_gem_object_funcs.vunmap for device specific handling.
703 */
704void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, struct iosys_map *map)
705{
706 struct drm_gem_object *obj = dma_buf->priv;
707
708 drm_gem_vunmap(obj, map);
709}
710EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);
711
712/**
713 * drm_gem_prime_mmap - PRIME mmap function for GEM drivers
714 * @obj: GEM object
715 * @vma: Virtual address range
716 *
717 * This function sets up a userspace mapping for PRIME exported buffers using
718 * the same codepath that is used for regular GEM buffer mapping on the DRM fd.
719 * The fake GEM offset is added to vma->vm_pgoff and &drm_driver->fops->mmap is
720 * called to set up the mapping.
721 */
722int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
723{
724 struct drm_file *priv;
725 struct file *fil;
726 int ret;
727
728 /* Add the fake offset */
729 vma->vm_pgoff += drm_vma_node_start(&obj->vma_node);
730
731 if (obj->funcs && obj->funcs->mmap) {
732 vma->vm_ops = obj->funcs->vm_ops;
733
734 drm_gem_object_get(obj);
735 ret = obj->funcs->mmap(obj, vma);
736 if (ret) {
737 drm_gem_object_put(obj);
738 return ret;
739 }
740 vma->vm_private_data = obj;
741 return 0;
742 }
743
744 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
745 fil = kzalloc(sizeof(*fil), GFP_KERNEL);
746 if (!priv || !fil) {
747 ret = -ENOMEM;
748 goto out;
749 }
750
751 /* Used by drm_gem_mmap() to lookup the GEM object */
752 priv->minor = obj->dev->primary;
753 fil->private_data = priv;
754
755 ret = drm_vma_node_allow(&obj->vma_node, priv);
756 if (ret)
757 goto out;
758
759 ret = obj->dev->driver->fops->mmap(fil, vma);
760
761 drm_vma_node_revoke(&obj->vma_node, priv);
762out:
763 kfree(priv);
764 kfree(fil);
765
766 return ret;
767}
768EXPORT_SYMBOL(drm_gem_prime_mmap);
769
770/**
771 * drm_gem_dmabuf_mmap - dma_buf mmap implementation for GEM
772 * @dma_buf: buffer to be mapped
773 * @vma: virtual address range
774 *
775 * Provides memory mapping for the buffer. This can be used as the
776 * &dma_buf_ops.mmap callback. It just forwards to drm_gem_prime_mmap().
777 *
778 * Returns 0 on success or a negative error code on failure.
779 */
780int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
781{
782 struct drm_gem_object *obj = dma_buf->priv;
783
784 return drm_gem_prime_mmap(obj, vma);
785}
786EXPORT_SYMBOL(drm_gem_dmabuf_mmap);
787
788static 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,
798};
799
800/**
801 * drm_prime_pages_to_sg - converts a page array into an sg list
802 * @dev: DRM device
803 * @pages: pointer to the array of page pointers to convert
804 * @nr_pages: length of the page vector
805 *
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.
809 *
810 * This is useful for implementing &drm_gem_object_funcs.get_sg_table.
811 */
812struct sg_table *drm_prime_pages_to_sg(struct drm_device *dev,
813 struct page **pages, unsigned int nr_pages)
814{
815 struct sg_table *sg;
816 size_t max_segment = 0;
817 int err;
818
819 sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
820 if (!sg)
821 return ERR_PTR(-ENOMEM);
822
823 if (dev)
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 (unsigned long)nr_pages << PAGE_SHIFT,
829 max_segment, GFP_KERNEL);
830 if (err) {
831 kfree(sg);
832 sg = ERR_PTR(err);
833 }
834 return sg;
835}
836EXPORT_SYMBOL(drm_prime_pages_to_sg);
837
838/**
839 * drm_prime_get_contiguous_size - returns the contiguous size of the buffer
840 * @sgt: sg_table describing the buffer to check
841 *
842 * This helper calculates the contiguous size in the DMA address space
843 * of the buffer described by the provided sg_table.
844 *
845 * This is useful for implementing
846 * &drm_gem_object_funcs.gem_prime_import_sg_table.
847 */
848unsigned long drm_prime_get_contiguous_size(struct sg_table *sgt)
849{
850 dma_addr_t expected = sg_dma_address(sgt->sgl);
851 struct scatterlist *sg;
852 unsigned long size = 0;
853 int i;
854
855 for_each_sgtable_dma_sg(sgt, sg, i) {
856 unsigned int len = sg_dma_len(sg);
857
858 if (!len)
859 break;
860 if (sg_dma_address(sg) != expected)
861 break;
862 expected += len;
863 size += len;
864 }
865 return size;
866}
867EXPORT_SYMBOL(drm_prime_get_contiguous_size);
868
869/**
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
873 *
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().
877 */
878struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj,
879 int flags)
880{
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,
886 .size = obj->size,
887 .flags = flags,
888 .priv = obj,
889 .resv = obj->resv,
890 };
891
892 return drm_gem_dmabuf_export(dev, &exp_info);
893}
894EXPORT_SYMBOL(drm_gem_prime_export);
895
896/**
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
901 *
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.
906 *
907 * Drivers must arrange to call drm_prime_gem_destroy() from their
908 * &drm_gem_object_funcs.free hook when using this function.
909 */
910struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev,
911 struct dma_buf *dma_buf,
912 struct device *attach_dev)
913{
914 struct dma_buf_attachment *attach;
915 struct sg_table *sgt;
916 struct drm_gem_object *obj;
917 int ret;
918
919 if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
920 obj = dma_buf->priv;
921 if (obj->dev == dev) {
922 /*
923 * Importing dmabuf exported from our own gem increases
924 * refcount on gem itself instead of f_count of dmabuf.
925 */
926 drm_gem_object_get(obj);
927 return obj;
928 }
929 }
930
931 if (!dev->driver->gem_prime_import_sg_table)
932 return ERR_PTR(-EINVAL);
933
934 attach = dma_buf_attach(dma_buf, attach_dev);
935 if (IS_ERR(attach))
936 return ERR_CAST(attach);
937
938 get_dma_buf(dma_buf);
939
940 sgt = dma_buf_map_attachment_unlocked(attach, DMA_BIDIRECTIONAL);
941 if (IS_ERR(sgt)) {
942 ret = PTR_ERR(sgt);
943 goto fail_detach;
944 }
945
946 obj = dev->driver->gem_prime_import_sg_table(dev, attach, sgt);
947 if (IS_ERR(obj)) {
948 ret = PTR_ERR(obj);
949 goto fail_unmap;
950 }
951
952 obj->import_attach = attach;
953 obj->resv = dma_buf->resv;
954
955 return obj;
956
957fail_unmap:
958 dma_buf_unmap_attachment_unlocked(attach, sgt, DMA_BIDIRECTIONAL);
959fail_detach:
960 dma_buf_detach(dma_buf, attach);
961 dma_buf_put(dma_buf);
962
963 return ERR_PTR(ret);
964}
965EXPORT_SYMBOL(drm_gem_prime_import_dev);
966
967/**
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
971 *
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().
976 *
977 * Drivers must arrange to call drm_prime_gem_destroy() from their
978 * &drm_gem_object_funcs.free hook when using this function.
979 */
980struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
981 struct dma_buf *dma_buf)
982{
983 return drm_gem_prime_import_dev(dev, dma_buf, dev->dev);
984}
985EXPORT_SYMBOL(drm_gem_prime_import);
986
987/**
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
992 *
993 * Exports an sg table into an array of pages.
994 *
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.
998 */
999int __deprecated drm_prime_sg_to_page_array(struct sg_table *sgt,
1000 struct page **pages,
1001 int max_entries)
1002{
1003 struct sg_page_iter page_iter;
1004 struct page **p = pages;
1005
1006 for_each_sgtable_page(sgt, &page_iter, 0) {
1007 if (WARN_ON(p - pages >= max_entries))
1008 return -1;
1009 *p++ = sg_page_iter_page(&page_iter);
1010 }
1011 return 0;
1012}
1013EXPORT_SYMBOL(drm_prime_sg_to_page_array);
1014
1015/**
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
1020 *
1021 * Exports an sg table into an array of addresses.
1022 *
1023 * Drivers should use this in their &drm_driver.gem_prime_import_sg_table
1024 * implementation.
1025 */
1026int drm_prime_sg_to_dma_addr_array(struct sg_table *sgt, dma_addr_t *addrs,
1027 int max_entries)
1028{
1029 struct sg_dma_page_iter dma_iter;
1030 dma_addr_t *a = addrs;
1031
1032 for_each_sgtable_dma_page(sgt, &dma_iter, 0) {
1033 if (WARN_ON(a - addrs >= max_entries))
1034 return -1;
1035 *a++ = sg_page_iter_dma_address(&dma_iter);
1036 }
1037 return 0;
1038}
1039EXPORT_SYMBOL(drm_prime_sg_to_dma_addr_array);
1040
1041/**
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
1045 *
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.
1048 */
1049void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
1050{
1051 struct dma_buf_attachment *attach;
1052 struct dma_buf *dma_buf;
1053
1054 attach = obj->import_attach;
1055 if (sg)
1056 dma_buf_unmap_attachment_unlocked(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);
1061}
1062EXPORT_SYMBOL(drm_prime_gem_destroy);