summaryrefslogtreecommitdiff
path: root/drivers/gpu/drm/drm_prime.c
blob: 372711a2876eb54eea1603adf2fadd8c3c954d33 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
/*
 * Copyright © 2012 Red Hat
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * Authors:
 *      Dave Airlie <airlied@redhat.com>
 *      Rob Clark <rob.clark@linaro.org>
 *
 */

#include <linux/export.h>
#include <linux/dma-buf.h>
#include <drm/drmP.h>

/*
 * DMA-BUF/GEM Object references and lifetime overview:
 *
 * On the export the dma_buf holds a reference to the exporting GEM
 * object. It takes this reference in handle_to_fd_ioctl, when it
 * first calls .prime_export and stores the exporting GEM object in
 * the dma_buf priv. This reference is released when the dma_buf
 * object goes away in the driver .release function.
 *
 * On the import the importing GEM object holds a reference to the
 * dma_buf (which in turn holds a ref to the exporting GEM object).
 * It takes that reference in the fd_to_handle ioctl.
 * It calls dma_buf_get, creates an attachment to it and stores the
 * attachment in the GEM object. When this attachment is destroyed
 * when the imported object is destroyed, we remove the attachment
 * and drop the reference to the dma_buf.
 *
 * Thus the chain of references always flows in one direction
 * (avoiding loops): importing_gem -> dmabuf -> exporting_gem
 *
 * Self-importing: if userspace is using PRIME as a replacement for flink
 * then it will get a fd->handle request for a GEM object that it created.
 * Drivers should detect this situation and return back the gem object
 * from the dma-buf private.  Prime will do this automatically for drivers that
 * use the drm_gem_prime_{import,export} helpers.
 */

struct drm_prime_member {
	struct list_head entry;
	struct dma_buf *dma_buf;
	uint32_t handle;
};

struct drm_prime_attachment {
	struct sg_table *sgt;
	enum dma_data_direction dir;
};

static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle)
{
	struct drm_prime_member *member;

	member = kmalloc(sizeof(*member), GFP_KERNEL);
	if (!member)
		return -ENOMEM;

	get_dma_buf(dma_buf);
	member->dma_buf = dma_buf;
	member->handle = handle;
	list_add(&member->entry, &prime_fpriv->head);
	return 0;
}

static int drm_gem_map_attach(struct dma_buf *dma_buf,
			      struct device *target_dev,
			      struct dma_buf_attachment *attach)
{
	struct drm_prime_attachment *prime_attach;
	struct drm_gem_object *obj = dma_buf->priv;
	struct drm_device *dev = obj->dev;

	prime_attach = kzalloc(sizeof(*prime_attach), GFP_KERNEL);
	if (!prime_attach)
		return -ENOMEM;

	prime_attach->dir = DMA_NONE;
	attach->priv = prime_attach;

	if (!dev->driver->gem_prime_pin)
		return 0;

	return dev->driver->gem_prime_pin(obj);
}

static void drm_gem_map_detach(struct dma_buf *dma_buf,
			       struct dma_buf_attachment *attach)
{
	struct drm_prime_attachment *prime_attach = attach->priv;
	struct drm_gem_object *obj = dma_buf->priv;
	struct drm_device *dev = obj->dev;
	struct sg_table *sgt;

	if (dev->driver->gem_prime_unpin)
		dev->driver->gem_prime_unpin(obj);

	if (!prime_attach)
		return;

	sgt = prime_attach->sgt;
	if (sgt) {
		if (prime_attach->dir != DMA_NONE)
			dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
					prime_attach->dir);
		sg_free_table(sgt);
	}

	kfree(sgt);
	kfree(prime_attach);
	attach->priv = NULL;
}

static void drm_prime_remove_buf_handle_locked(
		struct drm_prime_file_private *prime_fpriv,
		struct dma_buf *dma_buf)
{
	struct drm_prime_member *member, *safe;

	list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
		if (member->dma_buf == dma_buf) {
			dma_buf_put(dma_buf);
			list_del(&member->entry);
			kfree(member);
		}
	}
}

static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
		enum dma_data_direction dir)
{
	struct drm_prime_attachment *prime_attach = attach->priv;
	struct drm_gem_object *obj = attach->dmabuf->priv;
	struct sg_table *sgt;

	if (WARN_ON(dir == DMA_NONE || !prime_attach))
		return ERR_PTR(-EINVAL);

	/* return the cached mapping when possible */
	if (prime_attach->dir == dir)
		return prime_attach->sgt;

	/*
	 * two mappings with different directions for the same attachment are
	 * not allowed
	 */
	if (WARN_ON(prime_attach->dir != DMA_NONE))
		return ERR_PTR(-EBUSY);

	sgt = obj->dev->driver->gem_prime_get_sg_table(obj);

	if (!IS_ERR(sgt)) {
		if (!dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir)) {
			sg_free_table(sgt);
			kfree(sgt);
			sgt = ERR_PTR(-ENOMEM);
		} else {
			prime_attach->sgt = sgt;
			prime_attach->dir = dir;
		}
	}

	return sgt;
}

static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
		struct sg_table *sgt, enum dma_data_direction dir)
{
	/* nothing to be done here */
}

static void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
{
	struct drm_gem_object *obj = dma_buf->priv;

	if (obj->export_dma_buf == dma_buf) {
		/* drop the reference on the export fd holds */
		obj->export_dma_buf = NULL;
		drm_gem_object_unreference_unlocked(obj);
	}
}

static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
{
	struct drm_gem_object *obj = dma_buf->priv;
	struct drm_device *dev = obj->dev;

	return dev->driver->gem_prime_vmap(obj);
}

static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
{
	struct drm_gem_object *obj = dma_buf->priv;
	struct drm_device *dev = obj->dev;

	dev->driver->gem_prime_vunmap(obj, vaddr);
}

static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
		unsigned long page_num)
{
	return NULL;
}

static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
		unsigned long page_num, void *addr)
{

}
static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
		unsigned long page_num)
{
	return NULL;
}

static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
		unsigned long page_num, void *addr)
{

}

static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
		struct vm_area_struct *vma)
{
	struct drm_gem_object *obj = dma_buf->priv;
	struct drm_device *dev = obj->dev;

	if (!dev->driver->gem_prime_mmap)
		return -ENOSYS;

	return dev->driver->gem_prime_mmap(obj, vma);
}

static const struct dma_buf_ops drm_gem_prime_dmabuf_ops =  {
	.attach = drm_gem_map_attach,
	.detach = drm_gem_map_detach,
	.map_dma_buf = drm_gem_map_dma_buf,
	.unmap_dma_buf = drm_gem_unmap_dma_buf,
	.release = drm_gem_dmabuf_release,
	.kmap = drm_gem_dmabuf_kmap,
	.kmap_atomic = drm_gem_dmabuf_kmap_atomic,
	.kunmap = drm_gem_dmabuf_kunmap,
	.kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
	.mmap = drm_gem_dmabuf_mmap,
	.vmap = drm_gem_dmabuf_vmap,
	.vunmap = drm_gem_dmabuf_vunmap,
};

/**
 * DOC: PRIME Helpers
 *
 * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
 * simpler APIs by using the helper functions @drm_gem_prime_export and
 * @drm_gem_prime_import.  These functions implement dma-buf support in terms of
 * five lower-level driver callbacks:
 *
 * Export callbacks:
 *
 *  - @gem_prime_pin (optional): prepare a GEM object for exporting
 *
 *  - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
 *
 *  - @gem_prime_vmap: vmap a buffer exported by your driver
 *
 *  - @gem_prime_vunmap: vunmap a buffer exported by your driver
 *
 * Import callback:
 *
 *  - @gem_prime_import_sg_table (import): produce a GEM object from another
 *    driver's scatter/gather table
 */

struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
				     struct drm_gem_object *obj, int flags)
{
	return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size,
			     flags);
}
EXPORT_SYMBOL(drm_gem_prime_export);

int drm_gem_prime_handle_to_fd(struct drm_device *dev,
		struct drm_file *file_priv, uint32_t handle, uint32_t flags,
		int *prime_fd)
{
	struct drm_gem_object *obj;
	void *buf;
	int ret = 0;
	struct dma_buf *dmabuf;

	obj = drm_gem_object_lookup(dev, file_priv, handle);
	if (!obj)
		return -ENOENT;

	mutex_lock(&file_priv->prime.lock);
	/* re-export the original imported object */
	if (obj->import_attach) {
		dmabuf = obj->import_attach->dmabuf;
		goto out_have_obj;
	}

	if (obj->export_dma_buf) {
		dmabuf = obj->export_dma_buf;
		goto out_have_obj;
	}

	buf = dev->driver->gem_prime_export(dev, obj, flags);
	if (IS_ERR(buf)) {
		/* normally the created dma-buf takes ownership of the ref,
		 * but if that fails then drop the ref
		 */
		ret = PTR_ERR(buf);
		goto out;
	}
	obj->export_dma_buf = buf;

	/* if we've exported this buffer the cheat and add it to the import list
	 * so we get the correct handle back
	 */
	ret = drm_prime_add_buf_handle(&file_priv->prime,
				       obj->export_dma_buf, handle);
	if (ret)
		goto fail_put_dmabuf;

	ret = dma_buf_fd(buf, flags);
	if (ret < 0)
		goto fail_rm_handle;

	*prime_fd = ret;
	mutex_unlock(&file_priv->prime.lock);
	return 0;

out_have_obj:
	get_dma_buf(dmabuf);
	ret = dma_buf_fd(dmabuf, flags);
	if (ret < 0) {
		dma_buf_put(dmabuf);
	} else {
		*prime_fd = ret;
		ret = 0;
	}

	goto out;

fail_rm_handle:
	drm_prime_remove_buf_handle_locked(&file_priv->prime, buf);
fail_put_dmabuf:
	/* clear NOT to be checked when releasing dma_buf */
	obj->export_dma_buf = NULL;
	dma_buf_put(buf);
out:
	drm_gem_object_unreference_unlocked(obj);
	mutex_unlock(&file_priv->prime.lock);
	return ret;
}
EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);

struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
					    struct dma_buf *dma_buf)
{
	struct dma_buf_attachment *attach;
	struct sg_table *sgt;
	struct drm_gem_object *obj;
	int ret;

	if (!dev->driver->gem_prime_import_sg_table)
		return ERR_PTR(-EINVAL);

	if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
		obj = dma_buf->priv;
		if (obj->dev == dev) {
			/*
			 * Importing dmabuf exported from out own gem increases
			 * refcount on gem itself instead of f_count of dmabuf.
			 */
			drm_gem_object_reference(obj);
			return obj;
		}
	}

	attach = dma_buf_attach(dma_buf, dev->dev);
	if (IS_ERR(attach))
		return ERR_PTR(PTR_ERR(attach));

	get_dma_buf(dma_buf);

	sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
	if (IS_ERR(sgt)) {
		ret = PTR_ERR(sgt);
		goto fail_detach;
	}

	obj = dev->driver->gem_prime_import_sg_table(dev, dma_buf->size, sgt);
	if (IS_ERR(obj)) {
		ret = PTR_ERR(obj);
		goto fail_unmap;
	}

	obj->import_attach = attach;

	return obj;

fail_unmap:
	dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
fail_detach:
	dma_buf_detach(dma_buf, attach);
	dma_buf_put(dma_buf);

	return ERR_PTR(ret);
}
EXPORT_SYMBOL(drm_gem_prime_import);

int drm_gem_prime_fd_to_handle(struct drm_device *dev,
		struct drm_file *file_priv, int prime_fd, uint32_t *handle)
{
	struct dma_buf *dma_buf;
	struct drm_gem_object *obj;
	int ret;

	dma_buf = dma_buf_get(prime_fd);
	if (IS_ERR(dma_buf))
		return PTR_ERR(dma_buf);

	mutex_lock(&file_priv->prime.lock);

	ret = drm_prime_lookup_buf_handle(&file_priv->prime,
			dma_buf, handle);
	if (!ret) {
		ret = 0;
		goto out_put;
	}

	/* never seen this one, need to import */
	obj = dev->driver->gem_prime_import(dev, dma_buf);
	if (IS_ERR(obj)) {
		ret = PTR_ERR(obj);
		goto out_put;
	}

	ret = drm_gem_handle_create(file_priv, obj, handle);
	drm_gem_object_unreference_unlocked(obj);
	if (ret)
		goto out_put;

	ret = drm_prime_add_buf_handle(&file_priv->prime,
			dma_buf, *handle);
	if (ret)
		goto fail;

	mutex_unlock(&file_priv->prime.lock);

	dma_buf_put(dma_buf);

	return 0;

fail:
	/* hmm, if driver attached, we are relying on the free-object path
	 * to detach.. which seems ok..
	 */
	drm_gem_handle_delete(file_priv, *handle);
out_put:
	dma_buf_put(dma_buf);
	mutex_unlock(&file_priv->prime.lock);
	return ret;
}
EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);

int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
				 struct drm_file *file_priv)
{
	struct drm_prime_handle *args = data;
	uint32_t flags;

	if (!drm_core_check_feature(dev, DRIVER_PRIME))
		return -EINVAL;

	if (!dev->driver->prime_handle_to_fd)
		return -ENOSYS;

	/* check flags are valid */
	if (args->flags & ~DRM_CLOEXEC)
		return -EINVAL;

	/* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
	flags = args->flags & DRM_CLOEXEC;

	return dev->driver->prime_handle_to_fd(dev, file_priv,
			args->handle, flags, &args->fd);
}

int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
				 struct drm_file *file_priv)
{
	struct drm_prime_handle *args = data;

	if (!drm_core_check_feature(dev, DRIVER_PRIME))
		return -EINVAL;

	if (!dev->driver->prime_fd_to_handle)
		return -ENOSYS;

	return dev->driver->prime_fd_to_handle(dev, file_priv,
			args->fd, &args->handle);
}

/*
 * drm_prime_pages_to_sg
 *
 * this helper creates an sg table object from a set of pages
 * the driver is responsible for mapping the pages into the
 * importers address space
 */
struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
{
	struct sg_table *sg = NULL;
	int ret;

	sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
	if (!sg) {
		ret = -ENOMEM;
		goto out;
	}

	ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
				nr_pages << PAGE_SHIFT, GFP_KERNEL);
	if (ret)
		goto out;

	return sg;
out:
	kfree(sg);
	return ERR_PTR(ret);
}
EXPORT_SYMBOL(drm_prime_pages_to_sg);

/* export an sg table into an array of pages and addresses
   this is currently required by the TTM driver in order to do correct fault
   handling */
int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
				     dma_addr_t *addrs, int max_pages)
{
	unsigned count;
	struct scatterlist *sg;
	struct page *page;
	u32 len, offset;
	int pg_index;
	dma_addr_t addr;

	pg_index = 0;
	for_each_sg(sgt->sgl, sg, sgt->nents, count) {
		len = sg->length;
		offset = sg->offset;
		page = sg_page(sg);
		addr = sg_dma_address(sg);

		while (len > 0) {
			if (WARN_ON(pg_index >= max_pages))
				return -1;
			pages[pg_index] = page;
			if (addrs)
				addrs[pg_index] = addr;

			page++;
			addr += PAGE_SIZE;
			len -= PAGE_SIZE;
			pg_index++;
		}
	}
	return 0;
}
EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);
/* helper function to cleanup a GEM/prime object */
void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
{
	struct dma_buf_attachment *attach;
	struct dma_buf *dma_buf;
	attach = obj->import_attach;
	if (sg)
		dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
	dma_buf = attach->dmabuf;
	dma_buf_detach(attach->dmabuf, attach);
	/* remove the reference */
	dma_buf_put(dma_buf);
}
EXPORT_SYMBOL(drm_prime_gem_destroy);

void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
{
	INIT_LIST_HEAD(&prime_fpriv->head);
	mutex_init(&prime_fpriv->lock);
}
EXPORT_SYMBOL(drm_prime_init_file_private);

void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
{
	/* by now drm_gem_release should've made sure the list is empty */
	WARN_ON(!list_empty(&prime_fpriv->head));
}
EXPORT_SYMBOL(drm_prime_destroy_file_private);

int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle)
{
	struct drm_prime_member *member;

	list_for_each_entry(member, &prime_fpriv->head, entry) {
		if (member->dma_buf == dma_buf) {
			*handle = member->handle;
			return 0;
		}
	}
	return -ENOENT;
}
EXPORT_SYMBOL(drm_prime_lookup_buf_handle);

void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf)
{
	mutex_lock(&prime_fpriv->lock);
	drm_prime_remove_buf_handle_locked(prime_fpriv, dma_buf);
	mutex_unlock(&prime_fpriv->lock);
}
EXPORT_SYMBOL(drm_prime_remove_buf_handle);