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13#include <linux/module.h>
14#include <linux/mm.h>
15#include <linux/scatterlist.h>
16#include <linux/sched.h>
17#include <linux/slab.h>
18#include <linux/vmalloc.h>
19
20#include <media/videobuf2-core.h>
21#include <media/videobuf2-memops.h>
22#include <media/videobuf2-dma-sg.h>
23
24static int debug;
25module_param(debug, int, 0644);
26
27#define dprintk(level, fmt, arg...) \
28 do { \
29 if (debug >= level) \
30 printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg); \
31 } while (0)
32
33struct vb2_dma_sg_conf {
34 struct device *dev;
35};
36
37struct vb2_dma_sg_buf {
38 struct device *dev;
39 void *vaddr;
40 struct page **pages;
41 struct frame_vector *vec;
42 int offset;
43 enum dma_data_direction dma_dir;
44 struct sg_table sg_table;
45
46
47
48
49
50 struct sg_table *dma_sgt;
51 size_t size;
52 unsigned int num_pages;
53 atomic_t refcount;
54 struct vb2_vmarea_handler handler;
55
56 struct dma_buf_attachment *db_attach;
57};
58
59static void vb2_dma_sg_put(void *buf_priv);
60
61static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,
62 gfp_t gfp_flags)
63{
64 unsigned int last_page = 0;
65 int size = buf->size;
66
67 while (size > 0) {
68 struct page *pages;
69 int order;
70 int i;
71
72 order = get_order(size);
73
74 if ((PAGE_SIZE << order) > size)
75 order--;
76
77 pages = NULL;
78 while (!pages) {
79 pages = alloc_pages(GFP_KERNEL | __GFP_ZERO |
80 __GFP_NOWARN | gfp_flags, order);
81 if (pages)
82 break;
83
84 if (order == 0) {
85 while (last_page--)
86 __free_page(buf->pages[last_page]);
87 return -ENOMEM;
88 }
89 order--;
90 }
91
92 split_page(pages, order);
93 for (i = 0; i < (1 << order); i++)
94 buf->pages[last_page++] = &pages[i];
95
96 size -= PAGE_SIZE << order;
97 }
98
99 return 0;
100}
101
102static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size,
103 enum dma_data_direction dma_dir, gfp_t gfp_flags)
104{
105 struct vb2_dma_sg_conf *conf = alloc_ctx;
106 struct vb2_dma_sg_buf *buf;
107 struct sg_table *sgt;
108 int ret;
109 int num_pages;
110 DEFINE_DMA_ATTRS(attrs);
111
112 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
113
114 if (WARN_ON(alloc_ctx == NULL))
115 return NULL;
116 buf = kzalloc(sizeof *buf, GFP_KERNEL);
117 if (!buf)
118 return NULL;
119
120 buf->vaddr = NULL;
121 buf->dma_dir = dma_dir;
122 buf->offset = 0;
123 buf->size = size;
124
125 buf->num_pages = size >> PAGE_SHIFT;
126 buf->dma_sgt = &buf->sg_table;
127
128 buf->pages = kzalloc(buf->num_pages * sizeof(struct page *),
129 GFP_KERNEL);
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(conf->dev);
144
145 sgt = &buf->sg_table;
146
147
148
149
150 sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
151 buf->dma_dir, &attrs);
152 if (!sgt->nents)
153 goto fail_map;
154
155 buf->handler.refcount = &buf->refcount;
156 buf->handler.put = vb2_dma_sg_put;
157 buf->handler.arg = buf;
158
159 atomic_inc(&buf->refcount);
160
161 dprintk(1, "%s: Allocated buffer of %d pages\n",
162 __func__, buf->num_pages);
163 return buf;
164
165fail_map:
166 put_device(buf->dev);
167 sg_free_table(buf->dma_sgt);
168fail_table_alloc:
169 num_pages = buf->num_pages;
170 while (num_pages--)
171 __free_page(buf->pages[num_pages]);
172fail_pages_alloc:
173 kfree(buf->pages);
174fail_pages_array_alloc:
175 kfree(buf);
176 return NULL;
177}
178
179static void vb2_dma_sg_put(void *buf_priv)
180{
181 struct vb2_dma_sg_buf *buf = buf_priv;
182 struct sg_table *sgt = &buf->sg_table;
183 int i = buf->num_pages;
184
185 if (atomic_dec_and_test(&buf->refcount)) {
186 DEFINE_DMA_ATTRS(attrs);
187
188 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
189 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
190 buf->num_pages);
191 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
192 buf->dma_dir, &attrs);
193 if (buf->vaddr)
194 vm_unmap_ram(buf->vaddr, buf->num_pages);
195 sg_free_table(buf->dma_sgt);
196 while (--i >= 0)
197 __free_page(buf->pages[i]);
198 kfree(buf->pages);
199 put_device(buf->dev);
200 kfree(buf);
201 }
202}
203
204static void vb2_dma_sg_prepare(void *buf_priv)
205{
206 struct vb2_dma_sg_buf *buf = buf_priv;
207 struct sg_table *sgt = buf->dma_sgt;
208
209
210 if (buf->db_attach)
211 return;
212
213 dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
214}
215
216static void vb2_dma_sg_finish(void *buf_priv)
217{
218 struct vb2_dma_sg_buf *buf = buf_priv;
219 struct sg_table *sgt = buf->dma_sgt;
220
221
222 if (buf->db_attach)
223 return;
224
225 dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
226}
227
228static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
229 unsigned long size,
230 enum dma_data_direction dma_dir)
231{
232 struct vb2_dma_sg_conf *conf = alloc_ctx;
233 struct vb2_dma_sg_buf *buf;
234 struct sg_table *sgt;
235 DEFINE_DMA_ATTRS(attrs);
236 struct frame_vector *vec;
237
238 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
239 buf = kzalloc(sizeof *buf, GFP_KERNEL);
240 if (!buf)
241 return NULL;
242
243 buf->vaddr = NULL;
244 buf->dev = conf->dev;
245 buf->dma_dir = dma_dir;
246 buf->offset = vaddr & ~PAGE_MASK;
247 buf->size = size;
248 buf->dma_sgt = &buf->sg_table;
249 vec = vb2_create_framevec(vaddr, size, buf->dma_dir == DMA_FROM_DEVICE);
250 if (IS_ERR(vec))
251 goto userptr_fail_pfnvec;
252 buf->vec = vec;
253
254 buf->pages = frame_vector_pages(vec);
255 if (IS_ERR(buf->pages))
256 goto userptr_fail_sgtable;
257 buf->num_pages = frame_vector_count(vec);
258
259 if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
260 buf->num_pages, buf->offset, size, 0))
261 goto userptr_fail_sgtable;
262
263 sgt = &buf->sg_table;
264
265
266
267
268 sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
269 buf->dma_dir, &attrs);
270 if (!sgt->nents)
271 goto userptr_fail_map;
272
273 return buf;
274
275userptr_fail_map:
276 sg_free_table(&buf->sg_table);
277userptr_fail_sgtable:
278 vb2_destroy_framevec(vec);
279userptr_fail_pfnvec:
280 kfree(buf);
281 return NULL;
282}
283
284
285
286
287
288static void vb2_dma_sg_put_userptr(void *buf_priv)
289{
290 struct vb2_dma_sg_buf *buf = buf_priv;
291 struct sg_table *sgt = &buf->sg_table;
292 int i = buf->num_pages;
293 DEFINE_DMA_ATTRS(attrs);
294
295 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
296
297 dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
298 __func__, buf->num_pages);
299 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir,
300 &attrs);
301 if (buf->vaddr)
302 vm_unmap_ram(buf->vaddr, buf->num_pages);
303 sg_free_table(buf->dma_sgt);
304 while (--i >= 0) {
305 if (buf->dma_dir == DMA_FROM_DEVICE)
306 set_page_dirty_lock(buf->pages[i]);
307 }
308 vb2_destroy_framevec(buf->vec);
309 kfree(buf);
310}
311
312static void *vb2_dma_sg_vaddr(void *buf_priv)
313{
314 struct vb2_dma_sg_buf *buf = buf_priv;
315
316 BUG_ON(!buf);
317
318 if (!buf->vaddr) {
319 if (buf->db_attach)
320 buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf);
321 else
322 buf->vaddr = vm_map_ram(buf->pages,
323 buf->num_pages, -1, PAGE_KERNEL);
324 }
325
326
327 return buf->vaddr ? buf->vaddr + buf->offset : NULL;
328}
329
330static unsigned int vb2_dma_sg_num_users(void *buf_priv)
331{
332 struct vb2_dma_sg_buf *buf = buf_priv;
333
334 return atomic_read(&buf->refcount);
335}
336
337static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
338{
339 struct vb2_dma_sg_buf *buf = buf_priv;
340 unsigned long uaddr = vma->vm_start;
341 unsigned long usize = vma->vm_end - vma->vm_start;
342 int i = 0;
343
344 if (!buf) {
345 printk(KERN_ERR "No memory to map\n");
346 return -EINVAL;
347 }
348
349 do {
350 int ret;
351
352 ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
353 if (ret) {
354 printk(KERN_ERR "Remapping memory, error: %d\n", ret);
355 return ret;
356 }
357
358 uaddr += PAGE_SIZE;
359 usize -= PAGE_SIZE;
360 } while (usize > 0);
361
362
363
364
365
366 vma->vm_private_data = &buf->handler;
367 vma->vm_ops = &vb2_common_vm_ops;
368
369 vma->vm_ops->open(vma);
370
371 return 0;
372}
373
374
375
376
377
378struct vb2_dma_sg_attachment {
379 struct sg_table sgt;
380 enum dma_data_direction dma_dir;
381};
382
383static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
384 struct dma_buf_attachment *dbuf_attach)
385{
386 struct vb2_dma_sg_attachment *attach;
387 unsigned int i;
388 struct scatterlist *rd, *wr;
389 struct sg_table *sgt;
390 struct vb2_dma_sg_buf *buf = dbuf->priv;
391 int ret;
392
393 attach = kzalloc(sizeof(*attach), GFP_KERNEL);
394 if (!attach)
395 return -ENOMEM;
396
397 sgt = &attach->sgt;
398
399
400
401 ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL);
402 if (ret) {
403 kfree(attach);
404 return -ENOMEM;
405 }
406
407 rd = buf->dma_sgt->sgl;
408 wr = sgt->sgl;
409 for (i = 0; i < sgt->orig_nents; ++i) {
410 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
411 rd = sg_next(rd);
412 wr = sg_next(wr);
413 }
414
415 attach->dma_dir = DMA_NONE;
416 dbuf_attach->priv = attach;
417
418 return 0;
419}
420
421static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf,
422 struct dma_buf_attachment *db_attach)
423{
424 struct vb2_dma_sg_attachment *attach = db_attach->priv;
425 struct sg_table *sgt;
426
427 if (!attach)
428 return;
429
430 sgt = &attach->sgt;
431
432
433 if (attach->dma_dir != DMA_NONE)
434 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
435 attach->dma_dir);
436 sg_free_table(sgt);
437 kfree(attach);
438 db_attach->priv = NULL;
439}
440
441static struct sg_table *vb2_dma_sg_dmabuf_ops_map(
442 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
443{
444 struct vb2_dma_sg_attachment *attach = db_attach->priv;
445
446 struct mutex *lock = &db_attach->dmabuf->lock;
447 struct sg_table *sgt;
448
449 mutex_lock(lock);
450
451 sgt = &attach->sgt;
452
453 if (attach->dma_dir == dma_dir) {
454 mutex_unlock(lock);
455 return sgt;
456 }
457
458
459 if (attach->dma_dir != DMA_NONE) {
460 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
461 attach->dma_dir);
462 attach->dma_dir = DMA_NONE;
463 }
464
465
466 sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
467 dma_dir);
468 if (!sgt->nents) {
469 pr_err("failed to map scatterlist\n");
470 mutex_unlock(lock);
471 return ERR_PTR(-EIO);
472 }
473
474 attach->dma_dir = dma_dir;
475
476 mutex_unlock(lock);
477
478 return sgt;
479}
480
481static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
482 struct sg_table *sgt, enum dma_data_direction dma_dir)
483{
484
485}
486
487static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf)
488{
489
490 vb2_dma_sg_put(dbuf->priv);
491}
492
493static void *vb2_dma_sg_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
494{
495 struct vb2_dma_sg_buf *buf = dbuf->priv;
496
497 return buf->vaddr ? buf->vaddr + pgnum * PAGE_SIZE : NULL;
498}
499
500static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf)
501{
502 struct vb2_dma_sg_buf *buf = dbuf->priv;
503
504 return vb2_dma_sg_vaddr(buf);
505}
506
507static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf,
508 struct vm_area_struct *vma)
509{
510 return vb2_dma_sg_mmap(dbuf->priv, vma);
511}
512
513static struct dma_buf_ops vb2_dma_sg_dmabuf_ops = {
514 .attach = vb2_dma_sg_dmabuf_ops_attach,
515 .detach = vb2_dma_sg_dmabuf_ops_detach,
516 .map_dma_buf = vb2_dma_sg_dmabuf_ops_map,
517 .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap,
518 .kmap = vb2_dma_sg_dmabuf_ops_kmap,
519 .kmap_atomic = vb2_dma_sg_dmabuf_ops_kmap,
520 .vmap = vb2_dma_sg_dmabuf_ops_vmap,
521 .mmap = vb2_dma_sg_dmabuf_ops_mmap,
522 .release = vb2_dma_sg_dmabuf_ops_release,
523};
524
525static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags)
526{
527 struct vb2_dma_sg_buf *buf = buf_priv;
528 struct dma_buf *dbuf;
529 DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
530
531 exp_info.ops = &vb2_dma_sg_dmabuf_ops;
532 exp_info.size = buf->size;
533 exp_info.flags = flags;
534 exp_info.priv = buf;
535
536 if (WARN_ON(!buf->dma_sgt))
537 return NULL;
538
539 dbuf = dma_buf_export(&exp_info);
540 if (IS_ERR(dbuf))
541 return NULL;
542
543
544 atomic_inc(&buf->refcount);
545
546 return dbuf;
547}
548
549
550
551
552
553static int vb2_dma_sg_map_dmabuf(void *mem_priv)
554{
555 struct vb2_dma_sg_buf *buf = mem_priv;
556 struct sg_table *sgt;
557
558 if (WARN_ON(!buf->db_attach)) {
559 pr_err("trying to pin a non attached buffer\n");
560 return -EINVAL;
561 }
562
563 if (WARN_ON(buf->dma_sgt)) {
564 pr_err("dmabuf buffer is already pinned\n");
565 return 0;
566 }
567
568
569 sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
570 if (IS_ERR(sgt)) {
571 pr_err("Error getting dmabuf scatterlist\n");
572 return -EINVAL;
573 }
574
575 buf->dma_sgt = sgt;
576 buf->vaddr = NULL;
577
578 return 0;
579}
580
581static void vb2_dma_sg_unmap_dmabuf(void *mem_priv)
582{
583 struct vb2_dma_sg_buf *buf = mem_priv;
584 struct sg_table *sgt = buf->dma_sgt;
585
586 if (WARN_ON(!buf->db_attach)) {
587 pr_err("trying to unpin a not attached buffer\n");
588 return;
589 }
590
591 if (WARN_ON(!sgt)) {
592 pr_err("dmabuf buffer is already unpinned\n");
593 return;
594 }
595
596 if (buf->vaddr) {
597 dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr);
598 buf->vaddr = NULL;
599 }
600 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
601
602 buf->dma_sgt = NULL;
603}
604
605static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
606{
607 struct vb2_dma_sg_buf *buf = mem_priv;
608
609
610 if (WARN_ON(buf->dma_sgt))
611 vb2_dma_sg_unmap_dmabuf(buf);
612
613
614 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
615 kfree(buf);
616}
617
618static void *vb2_dma_sg_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
619 unsigned long size, enum dma_data_direction dma_dir)
620{
621 struct vb2_dma_sg_conf *conf = alloc_ctx;
622 struct vb2_dma_sg_buf *buf;
623 struct dma_buf_attachment *dba;
624
625 if (dbuf->size < size)
626 return ERR_PTR(-EFAULT);
627
628 buf = kzalloc(sizeof(*buf), GFP_KERNEL);
629 if (!buf)
630 return ERR_PTR(-ENOMEM);
631
632 buf->dev = conf->dev;
633
634 dba = dma_buf_attach(dbuf, buf->dev);
635 if (IS_ERR(dba)) {
636 pr_err("failed to attach dmabuf\n");
637 kfree(buf);
638 return dba;
639 }
640
641 buf->dma_dir = dma_dir;
642 buf->size = size;
643 buf->db_attach = dba;
644
645 return buf;
646}
647
648static void *vb2_dma_sg_cookie(void *buf_priv)
649{
650 struct vb2_dma_sg_buf *buf = buf_priv;
651
652 return buf->dma_sgt;
653}
654
655const struct vb2_mem_ops vb2_dma_sg_memops = {
656 .alloc = vb2_dma_sg_alloc,
657 .put = vb2_dma_sg_put,
658 .get_userptr = vb2_dma_sg_get_userptr,
659 .put_userptr = vb2_dma_sg_put_userptr,
660 .prepare = vb2_dma_sg_prepare,
661 .finish = vb2_dma_sg_finish,
662 .vaddr = vb2_dma_sg_vaddr,
663 .mmap = vb2_dma_sg_mmap,
664 .num_users = vb2_dma_sg_num_users,
665 .get_dmabuf = vb2_dma_sg_get_dmabuf,
666 .map_dmabuf = vb2_dma_sg_map_dmabuf,
667 .unmap_dmabuf = vb2_dma_sg_unmap_dmabuf,
668 .attach_dmabuf = vb2_dma_sg_attach_dmabuf,
669 .detach_dmabuf = vb2_dma_sg_detach_dmabuf,
670 .cookie = vb2_dma_sg_cookie,
671};
672EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
673
674void *vb2_dma_sg_init_ctx(struct device *dev)
675{
676 struct vb2_dma_sg_conf *conf;
677
678 conf = kzalloc(sizeof(*conf), GFP_KERNEL);
679 if (!conf)
680 return ERR_PTR(-ENOMEM);
681
682 conf->dev = dev;
683
684 return conf;
685}
686EXPORT_SYMBOL_GPL(vb2_dma_sg_init_ctx);
687
688void vb2_dma_sg_cleanup_ctx(void *alloc_ctx)
689{
690 if (!IS_ERR_OR_NULL(alloc_ctx))
691 kfree(alloc_ctx);
692}
693EXPORT_SYMBOL_GPL(vb2_dma_sg_cleanup_ctx);
694
695MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
696MODULE_AUTHOR("Andrzej Pietrasiewicz");
697MODULE_LICENSE("GPL");
698