1 /*
2 * videobuf2-dma-contig.c - DMA contig memory allocator for videobuf2
3 *
4 * Copyright (C) 2010 Samsung Electronics
5 *
6 * Author: Pawel Osciak <pawel@osciak.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation.
11 */
12
13 #include <linux/dma-buf.h>
14 #include <linux/dma-resv.h>
15 #include <linux/module.h>
16 #include <linux/refcount.h>
17 #include <linux/scatterlist.h>
18 #include <linux/sched.h>
19 #include <linux/slab.h>
20 #include <linux/dma-mapping.h>
21 #include <linux/highmem.h>
22
23 #include <media/videobuf2-v4l2.h>
24 #include <media/videobuf2-dma-contig.h>
25 #include <media/videobuf2-memops.h>
26
27 struct vb2_dc_buf {
28 struct device *dev;
29 void *vaddr;
30 unsigned long size;
31 void *cookie;
32 dma_addr_t dma_addr;
33 unsigned long attrs;
34 enum dma_data_direction dma_dir;
35 struct sg_table *dma_sgt;
36 struct frame_vector *vec;
37
38 /* MMAP related */
39 struct vb2_vmarea_handler handler;
40 refcount_t refcount;
41 struct sg_table *sgt_base;
42
43 /* DMABUF related */
44 struct dma_buf_attachment *db_attach;
45
46 struct vb2_buffer *vb;
47 bool non_coherent_mem;
48 };
49
50 /*********************************************/
51 /* scatterlist table functions */
52 /*********************************************/
53
vb2_dc_get_contiguous_size(struct sg_table * sgt)54 static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt)
55 {
56 struct scatterlist *s;
57 dma_addr_t expected = sg_dma_address(sgt->sgl);
58 unsigned int i;
59 unsigned long size = 0;
60
61 for_each_sgtable_dma_sg(sgt, s, i) {
62 if (sg_dma_address(s) != expected)
63 break;
64 expected += sg_dma_len(s);
65 size += sg_dma_len(s);
66 }
67 return size;
68 }
69
70 /*********************************************/
71 /* callbacks for all buffers */
72 /*********************************************/
73
vb2_dc_cookie(struct vb2_buffer * vb,void * buf_priv)74 static void *vb2_dc_cookie(struct vb2_buffer *vb, void *buf_priv)
75 {
76 struct vb2_dc_buf *buf = buf_priv;
77
78 return &buf->dma_addr;
79 }
80
81 /*
82 * This function may fail if:
83 *
84 * - dma_buf_vmap() fails
85 * E.g. due to lack of virtual mapping address space, or due to
86 * dmabuf->ops misconfiguration.
87 *
88 * - dma_vmap_noncontiguous() fails
89 * For instance, when requested buffer size is larger than totalram_pages().
90 * Relevant for buffers that use non-coherent memory.
91 *
92 * - Queue DMA attrs have DMA_ATTR_NO_KERNEL_MAPPING set
93 * Relevant for buffers that use coherent memory.
94 */
vb2_dc_vaddr(struct vb2_buffer * vb,void * buf_priv)95 static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv)
96 {
97 struct vb2_dc_buf *buf = buf_priv;
98
99 if (buf->vaddr)
100 return buf->vaddr;
101
102 if (buf->db_attach) {
103 struct iosys_map map;
104
105 if (!dma_buf_vmap_unlocked(buf->db_attach->dmabuf, &map))
106 buf->vaddr = map.vaddr;
107
108 return buf->vaddr;
109 }
110
111 if (buf->non_coherent_mem)
112 buf->vaddr = dma_vmap_noncontiguous(buf->dev, buf->size,
113 buf->dma_sgt);
114 return buf->vaddr;
115 }
116
vb2_dc_num_users(void * buf_priv)117 static unsigned int vb2_dc_num_users(void *buf_priv)
118 {
119 struct vb2_dc_buf *buf = buf_priv;
120
121 return refcount_read(&buf->refcount);
122 }
123
vb2_dc_prepare(void * buf_priv)124 static void vb2_dc_prepare(void *buf_priv)
125 {
126 struct vb2_dc_buf *buf = buf_priv;
127 struct sg_table *sgt = buf->dma_sgt;
128
129 /* This takes care of DMABUF and user-enforced cache sync hint */
130 if (buf->vb->skip_cache_sync_on_prepare)
131 return;
132
133 if (!buf->non_coherent_mem)
134 return;
135
136 /* Non-coherent MMAP only */
137 if (buf->vaddr)
138 flush_kernel_vmap_range(buf->vaddr, buf->size);
139
140 /* For both USERPTR and non-coherent MMAP */
141 dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
142 }
143
vb2_dc_finish(void * buf_priv)144 static void vb2_dc_finish(void *buf_priv)
145 {
146 struct vb2_dc_buf *buf = buf_priv;
147 struct sg_table *sgt = buf->dma_sgt;
148
149 /* This takes care of DMABUF and user-enforced cache sync hint */
150 if (buf->vb->skip_cache_sync_on_finish)
151 return;
152
153 if (!buf->non_coherent_mem)
154 return;
155
156 /* Non-coherent MMAP only */
157 if (buf->vaddr)
158 invalidate_kernel_vmap_range(buf->vaddr, buf->size);
159
160 /* For both USERPTR and non-coherent MMAP */
161 dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
162 }
163
164 /*********************************************/
165 /* callbacks for MMAP buffers */
166 /*********************************************/
167
vb2_dc_put(void * buf_priv)168 static void vb2_dc_put(void *buf_priv)
169 {
170 struct vb2_dc_buf *buf = buf_priv;
171
172 if (!refcount_dec_and_test(&buf->refcount))
173 return;
174
175 if (buf->non_coherent_mem) {
176 if (buf->vaddr)
177 dma_vunmap_noncontiguous(buf->dev, buf->vaddr);
178 dma_free_noncontiguous(buf->dev, buf->size,
179 buf->dma_sgt, buf->dma_dir);
180 } else {
181 if (buf->sgt_base) {
182 sg_free_table(buf->sgt_base);
183 kfree(buf->sgt_base);
184 }
185 dma_free_attrs(buf->dev, buf->size, buf->cookie,
186 buf->dma_addr, buf->attrs);
187 }
188 put_device(buf->dev);
189 kfree(buf);
190 }
191
vb2_dc_alloc_coherent(struct vb2_dc_buf * buf)192 static int vb2_dc_alloc_coherent(struct vb2_dc_buf *buf)
193 {
194 struct vb2_queue *q = buf->vb->vb2_queue;
195
196 buf->cookie = dma_alloc_attrs(buf->dev,
197 buf->size,
198 &buf->dma_addr,
199 GFP_KERNEL | q->gfp_flags,
200 buf->attrs);
201 if (!buf->cookie)
202 return -ENOMEM;
203
204 if (q->dma_attrs & DMA_ATTR_NO_KERNEL_MAPPING)
205 return 0;
206
207 buf->vaddr = buf->cookie;
208 return 0;
209 }
210
vb2_dc_alloc_non_coherent(struct vb2_dc_buf * buf)211 static int vb2_dc_alloc_non_coherent(struct vb2_dc_buf *buf)
212 {
213 struct vb2_queue *q = buf->vb->vb2_queue;
214
215 buf->dma_sgt = dma_alloc_noncontiguous(buf->dev,
216 buf->size,
217 buf->dma_dir,
218 GFP_KERNEL | q->gfp_flags,
219 buf->attrs);
220 if (!buf->dma_sgt)
221 return -ENOMEM;
222
223 buf->dma_addr = sg_dma_address(buf->dma_sgt->sgl);
224
225 /*
226 * For non-coherent buffers the kernel mapping is created on demand
227 * in vb2_dc_vaddr().
228 */
229 return 0;
230 }
231
vb2_dc_alloc(struct vb2_buffer * vb,struct device * dev,unsigned long size)232 static void *vb2_dc_alloc(struct vb2_buffer *vb,
233 struct device *dev,
234 unsigned long size)
235 {
236 struct vb2_dc_buf *buf;
237 int ret;
238
239 if (WARN_ON(!dev))
240 return ERR_PTR(-EINVAL);
241
242 buf = kzalloc(sizeof *buf, GFP_KERNEL);
243 if (!buf)
244 return ERR_PTR(-ENOMEM);
245
246 buf->attrs = vb->vb2_queue->dma_attrs;
247 buf->dma_dir = vb->vb2_queue->dma_dir;
248 buf->vb = vb;
249 buf->non_coherent_mem = vb->vb2_queue->non_coherent_mem;
250
251 buf->size = size;
252 /* Prevent the device from being released while the buffer is used */
253 buf->dev = get_device(dev);
254
255 if (buf->non_coherent_mem)
256 ret = vb2_dc_alloc_non_coherent(buf);
257 else
258 ret = vb2_dc_alloc_coherent(buf);
259
260 if (ret) {
261 dev_err(dev, "dma alloc of size %lu failed\n", size);
262 kfree(buf);
263 return ERR_PTR(-ENOMEM);
264 }
265
266 buf->handler.refcount = &buf->refcount;
267 buf->handler.put = vb2_dc_put;
268 buf->handler.arg = buf;
269
270 refcount_set(&buf->refcount, 1);
271
272 return buf;
273 }
274
vb2_dc_mmap(void * buf_priv,struct vm_area_struct * vma)275 static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
276 {
277 struct vb2_dc_buf *buf = buf_priv;
278 int ret;
279
280 if (!buf) {
281 printk(KERN_ERR "No buffer to map\n");
282 return -EINVAL;
283 }
284
285 if (buf->non_coherent_mem)
286 ret = dma_mmap_noncontiguous(buf->dev, vma, buf->size,
287 buf->dma_sgt);
288 else
289 ret = dma_mmap_attrs(buf->dev, vma, buf->cookie, buf->dma_addr,
290 buf->size, buf->attrs);
291 if (ret) {
292 pr_err("Remapping memory failed, error: %d\n", ret);
293 return ret;
294 }
295
296 vm_flags_set(vma, VM_DONTEXPAND | VM_DONTDUMP);
297 vma->vm_private_data = &buf->handler;
298 vma->vm_ops = &vb2_common_vm_ops;
299
300 vma->vm_ops->open(vma);
301
302 pr_debug("%s: mapped dma addr 0x%08lx at 0x%08lx, size %lu\n",
303 __func__, (unsigned long)buf->dma_addr, vma->vm_start,
304 buf->size);
305
306 return 0;
307 }
308
309 /*********************************************/
310 /* DMABUF ops for exporters */
311 /*********************************************/
312
313 struct vb2_dc_attachment {
314 struct sg_table sgt;
315 enum dma_data_direction dma_dir;
316 };
317
vb2_dc_dmabuf_ops_attach(struct dma_buf * dbuf,struct dma_buf_attachment * dbuf_attach)318 static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf,
319 struct dma_buf_attachment *dbuf_attach)
320 {
321 struct vb2_dc_attachment *attach;
322 unsigned int i;
323 struct scatterlist *rd, *wr;
324 struct sg_table *sgt;
325 struct vb2_dc_buf *buf = dbuf->priv;
326 int ret;
327
328 attach = kzalloc(sizeof(*attach), GFP_KERNEL);
329 if (!attach)
330 return -ENOMEM;
331
332 sgt = &attach->sgt;
333 /* Copy the buf->base_sgt scatter list to the attachment, as we can't
334 * map the same scatter list to multiple attachments at the same time.
335 */
336 ret = sg_alloc_table(sgt, buf->sgt_base->orig_nents, GFP_KERNEL);
337 if (ret) {
338 kfree(attach);
339 return -ENOMEM;
340 }
341
342 rd = buf->sgt_base->sgl;
343 wr = sgt->sgl;
344 for (i = 0; i < sgt->orig_nents; ++i) {
345 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
346 rd = sg_next(rd);
347 wr = sg_next(wr);
348 }
349
350 attach->dma_dir = DMA_NONE;
351 dbuf_attach->priv = attach;
352
353 return 0;
354 }
355
vb2_dc_dmabuf_ops_detach(struct dma_buf * dbuf,struct dma_buf_attachment * db_attach)356 static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf,
357 struct dma_buf_attachment *db_attach)
358 {
359 struct vb2_dc_attachment *attach = db_attach->priv;
360 struct sg_table *sgt;
361
362 if (!attach)
363 return;
364
365 sgt = &attach->sgt;
366
367 /* release the scatterlist cache */
368 if (attach->dma_dir != DMA_NONE)
369 /*
370 * Cache sync can be skipped here, as the vb2_dc memory is
371 * allocated from device coherent memory, which means the
372 * memory locations do not require any explicit cache
373 * maintenance prior or after being used by the device.
374 */
375 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir,
376 DMA_ATTR_SKIP_CPU_SYNC);
377 sg_free_table(sgt);
378 kfree(attach);
379 db_attach->priv = NULL;
380 }
381
vb2_dc_dmabuf_ops_map(struct dma_buf_attachment * db_attach,enum dma_data_direction dma_dir)382 static struct sg_table *vb2_dc_dmabuf_ops_map(
383 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
384 {
385 struct vb2_dc_attachment *attach = db_attach->priv;
386 struct sg_table *sgt;
387
388 sgt = &attach->sgt;
389 /* return previously mapped sg table */
390 if (attach->dma_dir == dma_dir)
391 return sgt;
392
393 /* release any previous cache */
394 if (attach->dma_dir != DMA_NONE) {
395 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir,
396 DMA_ATTR_SKIP_CPU_SYNC);
397 attach->dma_dir = DMA_NONE;
398 }
399
400 /*
401 * mapping to the client with new direction, no cache sync
402 * required see comment in vb2_dc_dmabuf_ops_detach()
403 */
404 if (dma_map_sgtable(db_attach->dev, sgt, dma_dir,
405 DMA_ATTR_SKIP_CPU_SYNC)) {
406 pr_err("failed to map scatterlist\n");
407 return ERR_PTR(-EIO);
408 }
409
410 attach->dma_dir = dma_dir;
411
412 return sgt;
413 }
414
vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment * db_attach,struct sg_table * sgt,enum dma_data_direction dma_dir)415 static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
416 struct sg_table *sgt, enum dma_data_direction dma_dir)
417 {
418 /* nothing to be done here */
419 }
420
vb2_dc_dmabuf_ops_release(struct dma_buf * dbuf)421 static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf)
422 {
423 /* drop reference obtained in vb2_dc_get_dmabuf */
424 vb2_dc_put(dbuf->priv);
425 }
426
427 static int
vb2_dc_dmabuf_ops_begin_cpu_access(struct dma_buf * dbuf,enum dma_data_direction direction)428 vb2_dc_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf,
429 enum dma_data_direction direction)
430 {
431 return 0;
432 }
433
434 static int
vb2_dc_dmabuf_ops_end_cpu_access(struct dma_buf * dbuf,enum dma_data_direction direction)435 vb2_dc_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf,
436 enum dma_data_direction direction)
437 {
438 return 0;
439 }
440
vb2_dc_dmabuf_ops_vmap(struct dma_buf * dbuf,struct iosys_map * map)441 static int vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf, struct iosys_map *map)
442 {
443 struct vb2_dc_buf *buf;
444 void *vaddr;
445
446 buf = dbuf->priv;
447 vaddr = vb2_dc_vaddr(buf->vb, buf);
448 if (!vaddr)
449 return -EINVAL;
450
451 iosys_map_set_vaddr(map, vaddr);
452
453 return 0;
454 }
455
vb2_dc_dmabuf_ops_mmap(struct dma_buf * dbuf,struct vm_area_struct * vma)456 static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf,
457 struct vm_area_struct *vma)
458 {
459 dma_resv_assert_held(dbuf->resv);
460
461 return vb2_dc_mmap(dbuf->priv, vma);
462 }
463
464 static const struct dma_buf_ops vb2_dc_dmabuf_ops = {
465 .attach = vb2_dc_dmabuf_ops_attach,
466 .detach = vb2_dc_dmabuf_ops_detach,
467 .map_dma_buf = vb2_dc_dmabuf_ops_map,
468 .unmap_dma_buf = vb2_dc_dmabuf_ops_unmap,
469 .begin_cpu_access = vb2_dc_dmabuf_ops_begin_cpu_access,
470 .end_cpu_access = vb2_dc_dmabuf_ops_end_cpu_access,
471 .vmap = vb2_dc_dmabuf_ops_vmap,
472 .mmap = vb2_dc_dmabuf_ops_mmap,
473 .release = vb2_dc_dmabuf_ops_release,
474 };
475
vb2_dc_get_base_sgt(struct vb2_dc_buf * buf)476 static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
477 {
478 int ret;
479 struct sg_table *sgt;
480
481 if (buf->non_coherent_mem)
482 return buf->dma_sgt;
483
484 sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
485 if (!sgt) {
486 dev_err(buf->dev, "failed to alloc sg table\n");
487 return NULL;
488 }
489
490 ret = dma_get_sgtable_attrs(buf->dev, sgt, buf->cookie, buf->dma_addr,
491 buf->size, buf->attrs);
492 if (ret < 0) {
493 dev_err(buf->dev, "failed to get scatterlist from DMA API\n");
494 kfree(sgt);
495 return NULL;
496 }
497
498 return sgt;
499 }
500
vb2_dc_get_dmabuf(struct vb2_buffer * vb,void * buf_priv,unsigned long flags)501 static struct dma_buf *vb2_dc_get_dmabuf(struct vb2_buffer *vb,
502 void *buf_priv,
503 unsigned long flags)
504 {
505 struct vb2_dc_buf *buf = buf_priv;
506 struct dma_buf *dbuf;
507 DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
508
509 exp_info.ops = &vb2_dc_dmabuf_ops;
510 exp_info.size = buf->size;
511 exp_info.flags = flags;
512 exp_info.priv = buf;
513
514 if (!buf->sgt_base)
515 buf->sgt_base = vb2_dc_get_base_sgt(buf);
516
517 if (WARN_ON(!buf->sgt_base))
518 return NULL;
519
520 dbuf = dma_buf_export(&exp_info);
521 if (IS_ERR(dbuf))
522 return NULL;
523
524 /* dmabuf keeps reference to vb2 buffer */
525 refcount_inc(&buf->refcount);
526
527 return dbuf;
528 }
529
530 /*********************************************/
531 /* callbacks for USERPTR buffers */
532 /*********************************************/
533
vb2_dc_put_userptr(void * buf_priv)534 static void vb2_dc_put_userptr(void *buf_priv)
535 {
536 struct vb2_dc_buf *buf = buf_priv;
537 struct sg_table *sgt = buf->dma_sgt;
538 int i;
539 struct page **pages;
540
541 if (sgt) {
542 /*
543 * No need to sync to CPU, it's already synced to the CPU
544 * since the finish() memop will have been called before this.
545 */
546 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir,
547 DMA_ATTR_SKIP_CPU_SYNC);
548 pages = frame_vector_pages(buf->vec);
549 /* sgt should exist only if vector contains pages... */
550 BUG_ON(IS_ERR(pages));
551 if (buf->dma_dir == DMA_FROM_DEVICE ||
552 buf->dma_dir == DMA_BIDIRECTIONAL)
553 for (i = 0; i < frame_vector_count(buf->vec); i++)
554 set_page_dirty_lock(pages[i]);
555 sg_free_table(sgt);
556 kfree(sgt);
557 } else {
558 dma_unmap_resource(buf->dev, buf->dma_addr, buf->size,
559 buf->dma_dir, 0);
560 }
561 vb2_destroy_framevec(buf->vec);
562 kfree(buf);
563 }
564
vb2_dc_get_userptr(struct vb2_buffer * vb,struct device * dev,unsigned long vaddr,unsigned long size)565 static void *vb2_dc_get_userptr(struct vb2_buffer *vb, struct device *dev,
566 unsigned long vaddr, unsigned long size)
567 {
568 struct vb2_dc_buf *buf;
569 struct frame_vector *vec;
570 unsigned int offset;
571 int n_pages, i;
572 int ret = 0;
573 struct sg_table *sgt;
574 unsigned long contig_size;
575 unsigned long dma_align = dma_get_cache_alignment();
576
577 /* Only cache aligned DMA transfers are reliable */
578 if (!IS_ALIGNED(vaddr | size, dma_align)) {
579 pr_debug("user data must be aligned to %lu bytes\n", dma_align);
580 return ERR_PTR(-EINVAL);
581 }
582
583 if (!size) {
584 pr_debug("size is zero\n");
585 return ERR_PTR(-EINVAL);
586 }
587
588 if (WARN_ON(!dev))
589 return ERR_PTR(-EINVAL);
590
591 buf = kzalloc(sizeof *buf, GFP_KERNEL);
592 if (!buf)
593 return ERR_PTR(-ENOMEM);
594
595 buf->dev = dev;
596 buf->dma_dir = vb->vb2_queue->dma_dir;
597 buf->vb = vb;
598
599 offset = lower_32_bits(offset_in_page(vaddr));
600 vec = vb2_create_framevec(vaddr, size, buf->dma_dir == DMA_FROM_DEVICE ||
601 buf->dma_dir == DMA_BIDIRECTIONAL);
602 if (IS_ERR(vec)) {
603 ret = PTR_ERR(vec);
604 goto fail_buf;
605 }
606 buf->vec = vec;
607 n_pages = frame_vector_count(vec);
608 ret = frame_vector_to_pages(vec);
609 if (ret < 0) {
610 unsigned long *nums = frame_vector_pfns(vec);
611
612 /*
613 * Failed to convert to pages... Check the memory is physically
614 * contiguous and use direct mapping
615 */
616 for (i = 1; i < n_pages; i++)
617 if (nums[i-1] + 1 != nums[i])
618 goto fail_pfnvec;
619 buf->dma_addr = dma_map_resource(buf->dev,
620 __pfn_to_phys(nums[0]), size, buf->dma_dir, 0);
621 if (dma_mapping_error(buf->dev, buf->dma_addr)) {
622 ret = -ENOMEM;
623 goto fail_pfnvec;
624 }
625 goto out;
626 }
627
628 sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
629 if (!sgt) {
630 pr_err("failed to allocate sg table\n");
631 ret = -ENOMEM;
632 goto fail_pfnvec;
633 }
634
635 ret = sg_alloc_table_from_pages(sgt, frame_vector_pages(vec), n_pages,
636 offset, size, GFP_KERNEL);
637 if (ret) {
638 pr_err("failed to initialize sg table\n");
639 goto fail_sgt;
640 }
641
642 /*
643 * No need to sync to the device, this will happen later when the
644 * prepare() memop is called.
645 */
646 if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir,
647 DMA_ATTR_SKIP_CPU_SYNC)) {
648 pr_err("failed to map scatterlist\n");
649 ret = -EIO;
650 goto fail_sgt_init;
651 }
652
653 contig_size = vb2_dc_get_contiguous_size(sgt);
654 if (contig_size < size) {
655 pr_err("contiguous mapping is too small %lu/%lu\n",
656 contig_size, size);
657 ret = -EFAULT;
658 goto fail_map_sg;
659 }
660
661 buf->dma_addr = sg_dma_address(sgt->sgl);
662 buf->dma_sgt = sgt;
663 buf->non_coherent_mem = 1;
664
665 out:
666 buf->size = size;
667
668 return buf;
669
670 fail_map_sg:
671 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
672
673 fail_sgt_init:
674 sg_free_table(sgt);
675
676 fail_sgt:
677 kfree(sgt);
678
679 fail_pfnvec:
680 vb2_destroy_framevec(vec);
681
682 fail_buf:
683 kfree(buf);
684
685 return ERR_PTR(ret);
686 }
687
688 /*********************************************/
689 /* callbacks for DMABUF buffers */
690 /*********************************************/
691
vb2_dc_map_dmabuf(void * mem_priv)692 static int vb2_dc_map_dmabuf(void *mem_priv)
693 {
694 struct vb2_dc_buf *buf = mem_priv;
695 struct sg_table *sgt;
696 unsigned long contig_size;
697
698 if (WARN_ON(!buf->db_attach)) {
699 pr_err("trying to pin a non attached buffer\n");
700 return -EINVAL;
701 }
702
703 if (WARN_ON(buf->dma_sgt)) {
704 pr_err("dmabuf buffer is already pinned\n");
705 return 0;
706 }
707
708 /* get the associated scatterlist for this buffer */
709 sgt = dma_buf_map_attachment_unlocked(buf->db_attach, buf->dma_dir);
710 if (IS_ERR(sgt)) {
711 pr_err("Error getting dmabuf scatterlist\n");
712 return -EINVAL;
713 }
714
715 /* checking if dmabuf is big enough to store contiguous chunk */
716 contig_size = vb2_dc_get_contiguous_size(sgt);
717 if (contig_size < buf->size) {
718 pr_err("contiguous chunk is too small %lu/%lu\n",
719 contig_size, buf->size);
720 dma_buf_unmap_attachment_unlocked(buf->db_attach, sgt,
721 buf->dma_dir);
722 return -EFAULT;
723 }
724
725 buf->dma_addr = sg_dma_address(sgt->sgl);
726 buf->dma_sgt = sgt;
727 buf->vaddr = NULL;
728
729 return 0;
730 }
731
vb2_dc_unmap_dmabuf(void * mem_priv)732 static void vb2_dc_unmap_dmabuf(void *mem_priv)
733 {
734 struct vb2_dc_buf *buf = mem_priv;
735 struct sg_table *sgt = buf->dma_sgt;
736 struct iosys_map map = IOSYS_MAP_INIT_VADDR(buf->vaddr);
737
738 if (WARN_ON(!buf->db_attach)) {
739 pr_err("trying to unpin a not attached buffer\n");
740 return;
741 }
742
743 if (WARN_ON(!sgt)) {
744 pr_err("dmabuf buffer is already unpinned\n");
745 return;
746 }
747
748 if (buf->vaddr) {
749 dma_buf_vunmap_unlocked(buf->db_attach->dmabuf, &map);
750 buf->vaddr = NULL;
751 }
752 dma_buf_unmap_attachment_unlocked(buf->db_attach, sgt, buf->dma_dir);
753
754 buf->dma_addr = 0;
755 buf->dma_sgt = NULL;
756 }
757
vb2_dc_detach_dmabuf(void * mem_priv)758 static void vb2_dc_detach_dmabuf(void *mem_priv)
759 {
760 struct vb2_dc_buf *buf = mem_priv;
761
762 /* if vb2 works correctly you should never detach mapped buffer */
763 if (WARN_ON(buf->dma_addr))
764 vb2_dc_unmap_dmabuf(buf);
765
766 /* detach this attachment */
767 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
768 kfree(buf);
769 }
770
vb2_dc_attach_dmabuf(struct vb2_buffer * vb,struct device * dev,struct dma_buf * dbuf,unsigned long size)771 static void *vb2_dc_attach_dmabuf(struct vb2_buffer *vb, struct device *dev,
772 struct dma_buf *dbuf, unsigned long size)
773 {
774 struct vb2_dc_buf *buf;
775 struct dma_buf_attachment *dba;
776
777 if (dbuf->size < size)
778 return ERR_PTR(-EFAULT);
779
780 if (WARN_ON(!dev))
781 return ERR_PTR(-EINVAL);
782
783 buf = kzalloc(sizeof(*buf), GFP_KERNEL);
784 if (!buf)
785 return ERR_PTR(-ENOMEM);
786
787 buf->dev = dev;
788 buf->vb = vb;
789
790 /* create attachment for the dmabuf with the user device */
791 dba = dma_buf_attach(dbuf, buf->dev);
792 if (IS_ERR(dba)) {
793 pr_err("failed to attach dmabuf\n");
794 kfree(buf);
795 return dba;
796 }
797
798 buf->dma_dir = vb->vb2_queue->dma_dir;
799 buf->size = size;
800 buf->db_attach = dba;
801
802 return buf;
803 }
804
805 /*********************************************/
806 /* DMA CONTIG exported functions */
807 /*********************************************/
808
809 const struct vb2_mem_ops vb2_dma_contig_memops = {
810 .alloc = vb2_dc_alloc,
811 .put = vb2_dc_put,
812 .get_dmabuf = vb2_dc_get_dmabuf,
813 .cookie = vb2_dc_cookie,
814 .vaddr = vb2_dc_vaddr,
815 .mmap = vb2_dc_mmap,
816 .get_userptr = vb2_dc_get_userptr,
817 .put_userptr = vb2_dc_put_userptr,
818 .prepare = vb2_dc_prepare,
819 .finish = vb2_dc_finish,
820 .map_dmabuf = vb2_dc_map_dmabuf,
821 .unmap_dmabuf = vb2_dc_unmap_dmabuf,
822 .attach_dmabuf = vb2_dc_attach_dmabuf,
823 .detach_dmabuf = vb2_dc_detach_dmabuf,
824 .num_users = vb2_dc_num_users,
825 };
826 EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
827
828 /**
829 * vb2_dma_contig_set_max_seg_size() - configure DMA max segment size
830 * @dev: device for configuring DMA parameters
831 * @size: size of DMA max segment size to set
832 *
833 * To allow mapping the scatter-list into a single chunk in the DMA
834 * address space, the device is required to have the DMA max segment
835 * size parameter set to a value larger than the buffer size. Otherwise,
836 * the DMA-mapping subsystem will split the mapping into max segment
837 * size chunks. This function sets the DMA max segment size
838 * parameter to let DMA-mapping map a buffer as a single chunk in DMA
839 * address space.
840 * This code assumes that the DMA-mapping subsystem will merge all
841 * scatterlist segments if this is really possible (for example when
842 * an IOMMU is available and enabled).
843 * Ideally, this parameter should be set by the generic bus code, but it
844 * is left with the default 64KiB value due to historical litmiations in
845 * other subsystems (like limited USB host drivers) and there no good
846 * place to set it to the proper value.
847 * This function should be called from the drivers, which are known to
848 * operate on platforms with IOMMU and provide access to shared buffers
849 * (either USERPTR or DMABUF). This should be done before initializing
850 * videobuf2 queue.
851 */
vb2_dma_contig_set_max_seg_size(struct device * dev,unsigned int size)852 int vb2_dma_contig_set_max_seg_size(struct device *dev, unsigned int size)
853 {
854 if (!dev->dma_parms) {
855 dev_err(dev, "Failed to set max_seg_size: dma_parms is NULL\n");
856 return -ENODEV;
857 }
858 if (dma_get_max_seg_size(dev) < size)
859 return dma_set_max_seg_size(dev, size);
860
861 return 0;
862 }
863 EXPORT_SYMBOL_GPL(vb2_dma_contig_set_max_seg_size);
864
865 MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2");
866 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
867 MODULE_LICENSE("GPL");
868 MODULE_IMPORT_NS(DMA_BUF);
869