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13#include <linux/module.h>
14#include <linux/mm.h>
15#include <linux/refcount.h>
16#include <linux/scatterlist.h>
17#include <linux/sched.h>
18#include <linux/slab.h>
19#include <linux/vmalloc.h>
20
21#include <media/videobuf2-v4l2.h>
22#include <media/videobuf2-memops.h>
23#include <media/videobuf2-dma-sg.h>
24
25static int debug;
26module_param(debug, int, 0644);
27
28#define dprintk(level, fmt, arg...) \
29 do { \
30 if (debug >= level) \
31 printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg); \
32 } while (0)
33
34struct vb2_dma_sg_buf {
35 struct device *dev;
36 void *vaddr;
37 struct page **pages;
38 struct frame_vector *vec;
39 int offset;
40 enum dma_data_direction dma_dir;
41 struct sg_table sg_table;
42
43
44
45
46
47 struct sg_table *dma_sgt;
48 size_t size;
49 unsigned int num_pages;
50 refcount_t refcount;
51 struct vb2_vmarea_handler handler;
52
53 struct dma_buf_attachment *db_attach;
54};
55
56static void vb2_dma_sg_put(void *buf_priv);
57
58static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,
59 gfp_t gfp_flags)
60{
61 unsigned int last_page = 0;
62 unsigned long size = buf->size;
63
64 while (size > 0) {
65 struct page *pages;
66 int order;
67 int i;
68
69 order = get_order(size);
70
71 if ((PAGE_SIZE << order) > size)
72 order--;
73
74 pages = NULL;
75 while (!pages) {
76 pages = alloc_pages(GFP_KERNEL | __GFP_ZERO |
77 __GFP_NOWARN | gfp_flags, order);
78 if (pages)
79 break;
80
81 if (order == 0) {
82 while (last_page--)
83 __free_page(buf->pages[last_page]);
84 return -ENOMEM;
85 }
86 order--;
87 }
88
89 split_page(pages, order);
90 for (i = 0; i < (1 << order); i++)
91 buf->pages[last_page++] = &pages[i];
92
93 size -= PAGE_SIZE << order;
94 }
95
96 return 0;
97}
98
99static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs,
100 unsigned long size, enum dma_data_direction dma_dir,
101 gfp_t gfp_flags)
102{
103 struct vb2_dma_sg_buf *buf;
104 struct sg_table *sgt;
105 int ret;
106 int num_pages;
107
108 if (WARN_ON(!dev) || WARN_ON(!size))
109 return ERR_PTR(-EINVAL);
110
111 buf = kzalloc(sizeof *buf, GFP_KERNEL);
112 if (!buf)
113 return ERR_PTR(-ENOMEM);
114
115 buf->vaddr = NULL;
116 buf->dma_dir = dma_dir;
117 buf->offset = 0;
118 buf->size = size;
119
120 buf->num_pages = size >> PAGE_SHIFT;
121 buf->dma_sgt = &buf->sg_table;
122
123
124
125
126
127
128 buf->pages = kvmalloc_array(buf->num_pages, sizeof(struct page *),
129 GFP_KERNEL | __GFP_ZERO);
130 if (!buf->pages)
131 goto fail_pages_array_alloc;
132
133 ret = vb2_dma_sg_alloc_compacted(buf, gfp_flags);
134 if (ret)
135 goto fail_pages_alloc;
136
137 ret = sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
138 buf->num_pages, 0, size, GFP_KERNEL);
139 if (ret)
140 goto fail_table_alloc;
141
142
143 buf->dev = get_device(dev);
144
145 sgt = &buf->sg_table;
146
147
148
149
150 if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir,
151 DMA_ATTR_SKIP_CPU_SYNC))
152 goto fail_map;
153
154 buf->handler.refcount = &buf->refcount;
155 buf->handler.put = vb2_dma_sg_put;
156 buf->handler.arg = buf;
157
158 refcount_set(&buf->refcount, 1);
159
160 dprintk(1, "%s: Allocated buffer of %d pages\n",
161 __func__, buf->num_pages);
162 return buf;
163
164fail_map:
165 put_device(buf->dev);
166 sg_free_table(buf->dma_sgt);
167fail_table_alloc:
168 num_pages = buf->num_pages;
169 while (num_pages--)
170 __free_page(buf->pages[num_pages]);
171fail_pages_alloc:
172 kvfree(buf->pages);
173fail_pages_array_alloc:
174 kfree(buf);
175 return ERR_PTR(-ENOMEM);
176}
177
178static void vb2_dma_sg_put(void *buf_priv)
179{
180 struct vb2_dma_sg_buf *buf = buf_priv;
181 struct sg_table *sgt = &buf->sg_table;
182 int i = buf->num_pages;
183
184 if (refcount_dec_and_test(&buf->refcount)) {
185 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
186 buf->num_pages);
187 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir,
188 DMA_ATTR_SKIP_CPU_SYNC);
189 if (buf->vaddr)
190 vm_unmap_ram(buf->vaddr, buf->num_pages);
191 sg_free_table(buf->dma_sgt);
192 while (--i >= 0)
193 __free_page(buf->pages[i]);
194 kvfree(buf->pages);
195 put_device(buf->dev);
196 kfree(buf);
197 }
198}
199
200static void vb2_dma_sg_prepare(void *buf_priv)
201{
202 struct vb2_dma_sg_buf *buf = buf_priv;
203 struct sg_table *sgt = buf->dma_sgt;
204
205 dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
206}
207
208static void vb2_dma_sg_finish(void *buf_priv)
209{
210 struct vb2_dma_sg_buf *buf = buf_priv;
211 struct sg_table *sgt = buf->dma_sgt;
212
213 dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
214}
215
216static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr,
217 unsigned long size,
218 enum dma_data_direction dma_dir)
219{
220 struct vb2_dma_sg_buf *buf;
221 struct sg_table *sgt;
222 struct frame_vector *vec;
223
224 if (WARN_ON(!dev))
225 return ERR_PTR(-EINVAL);
226
227 buf = kzalloc(sizeof *buf, GFP_KERNEL);
228 if (!buf)
229 return ERR_PTR(-ENOMEM);
230
231 buf->vaddr = NULL;
232 buf->dev = dev;
233 buf->dma_dir = dma_dir;
234 buf->offset = vaddr & ~PAGE_MASK;
235 buf->size = size;
236 buf->dma_sgt = &buf->sg_table;
237 vec = vb2_create_framevec(vaddr, size);
238 if (IS_ERR(vec))
239 goto userptr_fail_pfnvec;
240 buf->vec = vec;
241
242 buf->pages = frame_vector_pages(vec);
243 if (IS_ERR(buf->pages))
244 goto userptr_fail_sgtable;
245 buf->num_pages = frame_vector_count(vec);
246
247 if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
248 buf->num_pages, buf->offset, size, 0))
249 goto userptr_fail_sgtable;
250
251 sgt = &buf->sg_table;
252
253
254
255
256 if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir,
257 DMA_ATTR_SKIP_CPU_SYNC))
258 goto userptr_fail_map;
259
260 return buf;
261
262userptr_fail_map:
263 sg_free_table(&buf->sg_table);
264userptr_fail_sgtable:
265 vb2_destroy_framevec(vec);
266userptr_fail_pfnvec:
267 kfree(buf);
268 return ERR_PTR(-ENOMEM);
269}
270
271
272
273
274
275static void vb2_dma_sg_put_userptr(void *buf_priv)
276{
277 struct vb2_dma_sg_buf *buf = buf_priv;
278 struct sg_table *sgt = &buf->sg_table;
279 int i = buf->num_pages;
280
281 dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
282 __func__, buf->num_pages);
283 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
284 if (buf->vaddr)
285 vm_unmap_ram(buf->vaddr, buf->num_pages);
286 sg_free_table(buf->dma_sgt);
287 if (buf->dma_dir == DMA_FROM_DEVICE ||
288 buf->dma_dir == DMA_BIDIRECTIONAL)
289 while (--i >= 0)
290 set_page_dirty_lock(buf->pages[i]);
291 vb2_destroy_framevec(buf->vec);
292 kfree(buf);
293}
294
295static void *vb2_dma_sg_vaddr(void *buf_priv)
296{
297 struct vb2_dma_sg_buf *buf = buf_priv;
298 struct dma_buf_map map;
299 int ret;
300
301 BUG_ON(!buf);
302
303 if (!buf->vaddr) {
304 if (buf->db_attach) {
305 ret = dma_buf_vmap(buf->db_attach->dmabuf, &map);
306 buf->vaddr = ret ? NULL : map.vaddr;
307 } else {
308 buf->vaddr = vm_map_ram(buf->pages, buf->num_pages, -1);
309 }
310 }
311
312
313 return buf->vaddr ? buf->vaddr + buf->offset : NULL;
314}
315
316static unsigned int vb2_dma_sg_num_users(void *buf_priv)
317{
318 struct vb2_dma_sg_buf *buf = buf_priv;
319
320 return refcount_read(&buf->refcount);
321}
322
323static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
324{
325 struct vb2_dma_sg_buf *buf = buf_priv;
326 int err;
327
328 if (!buf) {
329 printk(KERN_ERR "No memory to map\n");
330 return -EINVAL;
331 }
332
333 err = vm_map_pages(vma, buf->pages, buf->num_pages);
334 if (err) {
335 printk(KERN_ERR "Remapping memory, error: %d\n", err);
336 return err;
337 }
338
339
340
341
342 vma->vm_private_data = &buf->handler;
343 vma->vm_ops = &vb2_common_vm_ops;
344
345 vma->vm_ops->open(vma);
346
347 return 0;
348}
349
350
351
352
353
354struct vb2_dma_sg_attachment {
355 struct sg_table sgt;
356 enum dma_data_direction dma_dir;
357};
358
359static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf,
360 struct dma_buf_attachment *dbuf_attach)
361{
362 struct vb2_dma_sg_attachment *attach;
363 unsigned int i;
364 struct scatterlist *rd, *wr;
365 struct sg_table *sgt;
366 struct vb2_dma_sg_buf *buf = dbuf->priv;
367 int ret;
368
369 attach = kzalloc(sizeof(*attach), GFP_KERNEL);
370 if (!attach)
371 return -ENOMEM;
372
373 sgt = &attach->sgt;
374
375
376
377 ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL);
378 if (ret) {
379 kfree(attach);
380 return -ENOMEM;
381 }
382
383 rd = buf->dma_sgt->sgl;
384 wr = sgt->sgl;
385 for (i = 0; i < sgt->orig_nents; ++i) {
386 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
387 rd = sg_next(rd);
388 wr = sg_next(wr);
389 }
390
391 attach->dma_dir = DMA_NONE;
392 dbuf_attach->priv = attach;
393
394 return 0;
395}
396
397static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf,
398 struct dma_buf_attachment *db_attach)
399{
400 struct vb2_dma_sg_attachment *attach = db_attach->priv;
401 struct sg_table *sgt;
402
403 if (!attach)
404 return;
405
406 sgt = &attach->sgt;
407
408
409 if (attach->dma_dir != DMA_NONE)
410 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0);
411 sg_free_table(sgt);
412 kfree(attach);
413 db_attach->priv = NULL;
414}
415
416static struct sg_table *vb2_dma_sg_dmabuf_ops_map(
417 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
418{
419 struct vb2_dma_sg_attachment *attach = db_attach->priv;
420
421 struct mutex *lock = &db_attach->dmabuf->lock;
422 struct sg_table *sgt;
423
424 mutex_lock(lock);
425
426 sgt = &attach->sgt;
427
428 if (attach->dma_dir == dma_dir) {
429 mutex_unlock(lock);
430 return sgt;
431 }
432
433
434 if (attach->dma_dir != DMA_NONE) {
435 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0);
436 attach->dma_dir = DMA_NONE;
437 }
438
439
440 if (dma_map_sgtable(db_attach->dev, sgt, dma_dir, 0)) {
441 pr_err("failed to map scatterlist\n");
442 mutex_unlock(lock);
443 return ERR_PTR(-EIO);
444 }
445
446 attach->dma_dir = dma_dir;
447
448 mutex_unlock(lock);
449
450 return sgt;
451}
452
453static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
454 struct sg_table *sgt, enum dma_data_direction dma_dir)
455{
456
457}
458
459static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf)
460{
461
462 vb2_dma_sg_put(dbuf->priv);
463}
464
465static int
466vb2_dma_sg_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf,
467 enum dma_data_direction direction)
468{
469 struct vb2_dma_sg_buf *buf = dbuf->priv;
470 struct sg_table *sgt = buf->dma_sgt;
471
472 dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
473 return 0;
474}
475
476static int
477vb2_dma_sg_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf,
478 enum dma_data_direction direction)
479{
480 struct vb2_dma_sg_buf *buf = dbuf->priv;
481 struct sg_table *sgt = buf->dma_sgt;
482
483 dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
484 return 0;
485}
486
487static int vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf, struct dma_buf_map *map)
488{
489 struct vb2_dma_sg_buf *buf = dbuf->priv;
490
491 dma_buf_map_set_vaddr(map, buf->vaddr);
492
493 return 0;
494}
495
496static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf,
497 struct vm_area_struct *vma)
498{
499 return vb2_dma_sg_mmap(dbuf->priv, vma);
500}
501
502static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = {
503 .attach = vb2_dma_sg_dmabuf_ops_attach,
504 .detach = vb2_dma_sg_dmabuf_ops_detach,
505 .map_dma_buf = vb2_dma_sg_dmabuf_ops_map,
506 .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap,
507 .begin_cpu_access = vb2_dma_sg_dmabuf_ops_begin_cpu_access,
508 .end_cpu_access = vb2_dma_sg_dmabuf_ops_end_cpu_access,
509 .vmap = vb2_dma_sg_dmabuf_ops_vmap,
510 .mmap = vb2_dma_sg_dmabuf_ops_mmap,
511 .release = vb2_dma_sg_dmabuf_ops_release,
512};
513
514static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags)
515{
516 struct vb2_dma_sg_buf *buf = buf_priv;
517 struct dma_buf *dbuf;
518 DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
519
520 exp_info.ops = &vb2_dma_sg_dmabuf_ops;
521 exp_info.size = buf->size;
522 exp_info.flags = flags;
523 exp_info.priv = buf;
524
525 if (WARN_ON(!buf->dma_sgt))
526 return NULL;
527
528 dbuf = dma_buf_export(&exp_info);
529 if (IS_ERR(dbuf))
530 return NULL;
531
532
533 refcount_inc(&buf->refcount);
534
535 return dbuf;
536}
537
538
539
540
541
542static int vb2_dma_sg_map_dmabuf(void *mem_priv)
543{
544 struct vb2_dma_sg_buf *buf = mem_priv;
545 struct sg_table *sgt;
546
547 if (WARN_ON(!buf->db_attach)) {
548 pr_err("trying to pin a non attached buffer\n");
549 return -EINVAL;
550 }
551
552 if (WARN_ON(buf->dma_sgt)) {
553 pr_err("dmabuf buffer is already pinned\n");
554 return 0;
555 }
556
557
558 sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
559 if (IS_ERR(sgt)) {
560 pr_err("Error getting dmabuf scatterlist\n");
561 return -EINVAL;
562 }
563
564 buf->dma_sgt = sgt;
565 buf->vaddr = NULL;
566
567 return 0;
568}
569
570static void vb2_dma_sg_unmap_dmabuf(void *mem_priv)
571{
572 struct vb2_dma_sg_buf *buf = mem_priv;
573 struct sg_table *sgt = buf->dma_sgt;
574 struct dma_buf_map map = DMA_BUF_MAP_INIT_VADDR(buf->vaddr);
575
576 if (WARN_ON(!buf->db_attach)) {
577 pr_err("trying to unpin a not attached buffer\n");
578 return;
579 }
580
581 if (WARN_ON(!sgt)) {
582 pr_err("dmabuf buffer is already unpinned\n");
583 return;
584 }
585
586 if (buf->vaddr) {
587 dma_buf_vunmap(buf->db_attach->dmabuf, &map);
588 buf->vaddr = NULL;
589 }
590 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
591
592 buf->dma_sgt = NULL;
593}
594
595static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
596{
597 struct vb2_dma_sg_buf *buf = mem_priv;
598
599
600 if (WARN_ON(buf->dma_sgt))
601 vb2_dma_sg_unmap_dmabuf(buf);
602
603
604 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
605 kfree(buf);
606}
607
608static void *vb2_dma_sg_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
609 unsigned long size, enum dma_data_direction dma_dir)
610{
611 struct vb2_dma_sg_buf *buf;
612 struct dma_buf_attachment *dba;
613
614 if (WARN_ON(!dev))
615 return ERR_PTR(-EINVAL);
616
617 if (dbuf->size < size)
618 return ERR_PTR(-EFAULT);
619
620 buf = kzalloc(sizeof(*buf), GFP_KERNEL);
621 if (!buf)
622 return ERR_PTR(-ENOMEM);
623
624 buf->dev = dev;
625
626 dba = dma_buf_attach(dbuf, buf->dev);
627 if (IS_ERR(dba)) {
628 pr_err("failed to attach dmabuf\n");
629 kfree(buf);
630 return dba;
631 }
632
633 buf->dma_dir = dma_dir;
634 buf->size = size;
635 buf->db_attach = dba;
636
637 return buf;
638}
639
640static void *vb2_dma_sg_cookie(void *buf_priv)
641{
642 struct vb2_dma_sg_buf *buf = buf_priv;
643
644 return buf->dma_sgt;
645}
646
647const struct vb2_mem_ops vb2_dma_sg_memops = {
648 .alloc = vb2_dma_sg_alloc,
649 .put = vb2_dma_sg_put,
650 .get_userptr = vb2_dma_sg_get_userptr,
651 .put_userptr = vb2_dma_sg_put_userptr,
652 .prepare = vb2_dma_sg_prepare,
653 .finish = vb2_dma_sg_finish,
654 .vaddr = vb2_dma_sg_vaddr,
655 .mmap = vb2_dma_sg_mmap,
656 .num_users = vb2_dma_sg_num_users,
657 .get_dmabuf = vb2_dma_sg_get_dmabuf,
658 .map_dmabuf = vb2_dma_sg_map_dmabuf,
659 .unmap_dmabuf = vb2_dma_sg_unmap_dmabuf,
660 .attach_dmabuf = vb2_dma_sg_attach_dmabuf,
661 .detach_dmabuf = vb2_dma_sg_detach_dmabuf,
662 .cookie = vb2_dma_sg_cookie,
663};
664EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
665
666MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
667MODULE_AUTHOR("Andrzej Pietrasiewicz");
668MODULE_LICENSE("GPL");
669