2 * videobuf2-dma-contig.c - DMA contig memory allocator for videobuf2
4 * Copyright (C) 2010 Samsung Electronics
6 * Author: Pawel Osciak <pawel@osciak.com>
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.
13 #include <linux/dma-buf.h>
14 #include <linux/module.h>
15 #include <linux/scatterlist.h>
16 #include <linux/sched.h>
17 #include <linux/slab.h>
18 #include <linux/dma-mapping.h>
20 #include <media/videobuf2-core.h>
21 #include <media/videobuf2-dma-contig.h>
22 #include <media/videobuf2-memops.h>
33 enum dma_data_direction dma_dir
;
34 struct sg_table
*dma_sgt
;
37 struct vb2_vmarea_handler handler
;
39 struct sg_table
*sgt_base
;
42 struct vm_area_struct
*vma
;
45 struct dma_buf_attachment
*db_attach
;
48 /*********************************************/
49 /* scatterlist table functions */
50 /*********************************************/
53 static void vb2_dc_sgt_foreach_page(struct sg_table
*sgt
,
54 void (*cb
)(struct page
*pg
))
56 struct scatterlist
*s
;
59 for_each_sg(sgt
->sgl
, s
, sgt
->orig_nents
, i
) {
60 struct page
*page
= sg_page(s
);
61 unsigned int n_pages
= PAGE_ALIGN(s
->offset
+ s
->length
)
65 for (j
= 0; j
< n_pages
; ++j
, ++page
)
70 static unsigned long vb2_dc_get_contiguous_size(struct sg_table
*sgt
)
72 struct scatterlist
*s
;
73 dma_addr_t expected
= sg_dma_address(sgt
->sgl
);
75 unsigned long size
= 0;
77 for_each_sg(sgt
->sgl
, s
, sgt
->nents
, i
) {
78 if (sg_dma_address(s
) != expected
)
80 expected
= sg_dma_address(s
) + sg_dma_len(s
);
81 size
+= sg_dma_len(s
);
86 /*********************************************/
87 /* callbacks for all buffers */
88 /*********************************************/
90 static void *vb2_dc_cookie(void *buf_priv
)
92 struct vb2_dc_buf
*buf
= buf_priv
;
94 return &buf
->dma_addr
;
97 static void *vb2_dc_vaddr(void *buf_priv
)
99 struct vb2_dc_buf
*buf
= buf_priv
;
104 static unsigned int vb2_dc_num_users(void *buf_priv
)
106 struct vb2_dc_buf
*buf
= buf_priv
;
108 return atomic_read(&buf
->refcount
);
111 static void vb2_dc_prepare(void *buf_priv
)
113 struct vb2_dc_buf
*buf
= buf_priv
;
114 struct sg_table
*sgt
= buf
->dma_sgt
;
116 /* DMABUF exporter will flush the cache for us */
117 if (!sgt
|| buf
->db_attach
)
120 dma_sync_sg_for_device(buf
->dev
, sgt
->sgl
, sgt
->nents
, buf
->dma_dir
);
123 static void vb2_dc_finish(void *buf_priv
)
125 struct vb2_dc_buf
*buf
= buf_priv
;
126 struct sg_table
*sgt
= buf
->dma_sgt
;
128 /* DMABUF exporter will flush the cache for us */
129 if (!sgt
|| buf
->db_attach
)
132 dma_sync_sg_for_cpu(buf
->dev
, sgt
->sgl
, sgt
->nents
, buf
->dma_dir
);
135 /*********************************************/
136 /* callbacks for MMAP buffers */
137 /*********************************************/
139 static void vb2_dc_put(void *buf_priv
)
141 struct vb2_dc_buf
*buf
= buf_priv
;
143 if (!atomic_dec_and_test(&buf
->refcount
))
147 sg_free_table(buf
->sgt_base
);
148 kfree(buf
->sgt_base
);
150 dma_free_coherent(buf
->dev
, buf
->size
, buf
->vaddr
, buf
->dma_addr
);
151 put_device(buf
->dev
);
155 static void *vb2_dc_alloc(void *alloc_ctx
, unsigned long size
, gfp_t gfp_flags
)
157 struct vb2_dc_conf
*conf
= alloc_ctx
;
158 struct device
*dev
= conf
->dev
;
159 struct vb2_dc_buf
*buf
;
161 buf
= kzalloc(sizeof *buf
, GFP_KERNEL
);
163 return ERR_PTR(-ENOMEM
);
165 buf
->vaddr
= dma_alloc_coherent(dev
, size
, &buf
->dma_addr
,
166 GFP_KERNEL
| gfp_flags
);
168 dev_err(dev
, "dma_alloc_coherent of size %ld failed\n", size
);
170 return ERR_PTR(-ENOMEM
);
173 /* Prevent the device from being released while the buffer is used */
174 buf
->dev
= get_device(dev
);
177 buf
->handler
.refcount
= &buf
->refcount
;
178 buf
->handler
.put
= vb2_dc_put
;
179 buf
->handler
.arg
= buf
;
181 atomic_inc(&buf
->refcount
);
186 static int vb2_dc_mmap(void *buf_priv
, struct vm_area_struct
*vma
)
188 struct vb2_dc_buf
*buf
= buf_priv
;
192 printk(KERN_ERR
"No buffer to map\n");
197 * dma_mmap_* uses vm_pgoff as in-buffer offset, but we want to
202 ret
= dma_mmap_coherent(buf
->dev
, vma
, buf
->vaddr
,
203 buf
->dma_addr
, buf
->size
);
206 pr_err("Remapping memory failed, error: %d\n", ret
);
210 vma
->vm_flags
|= VM_DONTEXPAND
| VM_DONTDUMP
;
211 vma
->vm_private_data
= &buf
->handler
;
212 vma
->vm_ops
= &vb2_common_vm_ops
;
214 vma
->vm_ops
->open(vma
);
216 pr_debug("%s: mapped dma addr 0x%08lx at 0x%08lx, size %ld\n",
217 __func__
, (unsigned long)buf
->dma_addr
, vma
->vm_start
,
223 /*********************************************/
224 /* DMABUF ops for exporters */
225 /*********************************************/
227 struct vb2_dc_attachment
{
229 enum dma_data_direction dir
;
232 static int vb2_dc_dmabuf_ops_attach(struct dma_buf
*dbuf
, struct device
*dev
,
233 struct dma_buf_attachment
*dbuf_attach
)
235 struct vb2_dc_attachment
*attach
;
237 struct scatterlist
*rd
, *wr
;
238 struct sg_table
*sgt
;
239 struct vb2_dc_buf
*buf
= dbuf
->priv
;
242 attach
= kzalloc(sizeof(*attach
), GFP_KERNEL
);
247 /* Copy the buf->base_sgt scatter list to the attachment, as we can't
248 * map the same scatter list to multiple attachments at the same time.
250 ret
= sg_alloc_table(sgt
, buf
->sgt_base
->orig_nents
, GFP_KERNEL
);
256 rd
= buf
->sgt_base
->sgl
;
258 for (i
= 0; i
< sgt
->orig_nents
; ++i
) {
259 sg_set_page(wr
, sg_page(rd
), rd
->length
, rd
->offset
);
264 attach
->dir
= DMA_NONE
;
265 dbuf_attach
->priv
= attach
;
270 static void vb2_dc_dmabuf_ops_detach(struct dma_buf
*dbuf
,
271 struct dma_buf_attachment
*db_attach
)
273 struct vb2_dc_attachment
*attach
= db_attach
->priv
;
274 struct sg_table
*sgt
;
281 /* release the scatterlist cache */
282 if (attach
->dir
!= DMA_NONE
)
283 dma_unmap_sg(db_attach
->dev
, sgt
->sgl
, sgt
->orig_nents
,
287 db_attach
->priv
= NULL
;
290 static struct sg_table
*vb2_dc_dmabuf_ops_map(
291 struct dma_buf_attachment
*db_attach
, enum dma_data_direction dir
)
293 struct vb2_dc_attachment
*attach
= db_attach
->priv
;
294 /* stealing dmabuf mutex to serialize map/unmap operations */
295 struct mutex
*lock
= &db_attach
->dmabuf
->lock
;
296 struct sg_table
*sgt
;
302 /* return previously mapped sg table */
303 if (attach
->dir
== dir
) {
308 /* release any previous cache */
309 if (attach
->dir
!= DMA_NONE
) {
310 dma_unmap_sg(db_attach
->dev
, sgt
->sgl
, sgt
->orig_nents
,
312 attach
->dir
= DMA_NONE
;
315 /* mapping to the client with new direction */
316 ret
= dma_map_sg(db_attach
->dev
, sgt
->sgl
, sgt
->orig_nents
, dir
);
318 pr_err("failed to map scatterlist\n");
320 return ERR_PTR(-EIO
);
330 static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment
*db_attach
,
331 struct sg_table
*sgt
, enum dma_data_direction dir
)
333 /* nothing to be done here */
336 static void vb2_dc_dmabuf_ops_release(struct dma_buf
*dbuf
)
338 /* drop reference obtained in vb2_dc_get_dmabuf */
339 vb2_dc_put(dbuf
->priv
);
342 static void *vb2_dc_dmabuf_ops_kmap(struct dma_buf
*dbuf
, unsigned long pgnum
)
344 struct vb2_dc_buf
*buf
= dbuf
->priv
;
346 return buf
->vaddr
+ pgnum
* PAGE_SIZE
;
349 static void *vb2_dc_dmabuf_ops_vmap(struct dma_buf
*dbuf
)
351 struct vb2_dc_buf
*buf
= dbuf
->priv
;
356 static int vb2_dc_dmabuf_ops_mmap(struct dma_buf
*dbuf
,
357 struct vm_area_struct
*vma
)
359 return vb2_dc_mmap(dbuf
->priv
, vma
);
362 static struct dma_buf_ops vb2_dc_dmabuf_ops
= {
363 .attach
= vb2_dc_dmabuf_ops_attach
,
364 .detach
= vb2_dc_dmabuf_ops_detach
,
365 .map_dma_buf
= vb2_dc_dmabuf_ops_map
,
366 .unmap_dma_buf
= vb2_dc_dmabuf_ops_unmap
,
367 .kmap
= vb2_dc_dmabuf_ops_kmap
,
368 .kmap_atomic
= vb2_dc_dmabuf_ops_kmap
,
369 .vmap
= vb2_dc_dmabuf_ops_vmap
,
370 .mmap
= vb2_dc_dmabuf_ops_mmap
,
371 .release
= vb2_dc_dmabuf_ops_release
,
374 static struct sg_table
*vb2_dc_get_base_sgt(struct vb2_dc_buf
*buf
)
377 struct sg_table
*sgt
;
379 sgt
= kmalloc(sizeof(*sgt
), GFP_KERNEL
);
381 dev_err(buf
->dev
, "failed to alloc sg table\n");
385 ret
= dma_get_sgtable(buf
->dev
, sgt
, buf
->vaddr
, buf
->dma_addr
,
388 dev_err(buf
->dev
, "failed to get scatterlist from DMA API\n");
396 static struct dma_buf
*vb2_dc_get_dmabuf(void *buf_priv
)
398 struct vb2_dc_buf
*buf
= buf_priv
;
399 struct dma_buf
*dbuf
;
402 buf
->sgt_base
= vb2_dc_get_base_sgt(buf
);
404 if (WARN_ON(!buf
->sgt_base
))
407 dbuf
= dma_buf_export(buf
, &vb2_dc_dmabuf_ops
, buf
->size
, 0);
411 /* dmabuf keeps reference to vb2 buffer */
412 atomic_inc(&buf
->refcount
);
417 /*********************************************/
418 /* callbacks for USERPTR buffers */
419 /*********************************************/
421 static inline int vma_is_io(struct vm_area_struct
*vma
)
423 return !!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
));
426 static int vb2_dc_get_user_pages(unsigned long start
, struct page
**pages
,
427 int n_pages
, struct vm_area_struct
*vma
, int write
)
429 if (vma_is_io(vma
)) {
432 for (i
= 0; i
< n_pages
; ++i
, start
+= PAGE_SIZE
) {
434 int ret
= follow_pfn(vma
, start
, &pfn
);
437 pr_err("no page for address %lu\n", start
);
440 pages
[i
] = pfn_to_page(pfn
);
445 n
= get_user_pages(current
, current
->mm
, start
& PAGE_MASK
,
446 n_pages
, write
, 1, pages
, NULL
);
447 /* negative error means that no page was pinned */
450 pr_err("got only %d of %d user pages\n", n
, n_pages
);
452 put_page(pages
[--n
]);
460 static void vb2_dc_put_dirty_page(struct page
*page
)
462 set_page_dirty_lock(page
);
466 static void vb2_dc_put_userptr(void *buf_priv
)
468 struct vb2_dc_buf
*buf
= buf_priv
;
469 struct sg_table
*sgt
= buf
->dma_sgt
;
471 dma_unmap_sg(buf
->dev
, sgt
->sgl
, sgt
->orig_nents
, buf
->dma_dir
);
472 if (!vma_is_io(buf
->vma
))
473 vb2_dc_sgt_foreach_page(sgt
, vb2_dc_put_dirty_page
);
477 vb2_put_vma(buf
->vma
);
481 static void *vb2_dc_get_userptr(void *alloc_ctx
, unsigned long vaddr
,
482 unsigned long size
, int write
)
484 struct vb2_dc_conf
*conf
= alloc_ctx
;
485 struct vb2_dc_buf
*buf
;
488 unsigned long offset
;
492 struct vm_area_struct
*vma
;
493 struct sg_table
*sgt
;
494 unsigned long contig_size
;
495 unsigned long dma_align
= dma_get_cache_alignment();
497 /* Only cache aligned DMA transfers are reliable */
498 if (!IS_ALIGNED(vaddr
| size
, dma_align
)) {
499 pr_debug("user data must be aligned to %lu bytes\n", dma_align
);
500 return ERR_PTR(-EINVAL
);
504 pr_debug("size is zero\n");
505 return ERR_PTR(-EINVAL
);
508 buf
= kzalloc(sizeof *buf
, GFP_KERNEL
);
510 return ERR_PTR(-ENOMEM
);
512 buf
->dev
= conf
->dev
;
513 buf
->dma_dir
= write
? DMA_FROM_DEVICE
: DMA_TO_DEVICE
;
515 start
= vaddr
& PAGE_MASK
;
516 offset
= vaddr
& ~PAGE_MASK
;
517 end
= PAGE_ALIGN(vaddr
+ size
);
518 n_pages
= (end
- start
) >> PAGE_SHIFT
;
520 pages
= kmalloc(n_pages
* sizeof(pages
[0]), GFP_KERNEL
);
523 pr_err("failed to allocate pages table\n");
527 /* current->mm->mmap_sem is taken by videobuf2 core */
528 vma
= find_vma(current
->mm
, vaddr
);
530 pr_err("no vma for address %lu\n", vaddr
);
535 if (vma
->vm_end
< vaddr
+ size
) {
536 pr_err("vma at %lu is too small for %lu bytes\n", vaddr
, size
);
541 buf
->vma
= vb2_get_vma(vma
);
543 pr_err("failed to copy vma\n");
548 /* extract page list from userspace mapping */
549 ret
= vb2_dc_get_user_pages(start
, pages
, n_pages
, vma
, write
);
551 pr_err("failed to get user pages\n");
555 sgt
= kzalloc(sizeof(*sgt
), GFP_KERNEL
);
557 pr_err("failed to allocate sg table\n");
559 goto fail_get_user_pages
;
562 ret
= sg_alloc_table_from_pages(sgt
, pages
, n_pages
,
563 offset
, size
, GFP_KERNEL
);
565 pr_err("failed to initialize sg table\n");
569 /* pages are no longer needed */
573 sgt
->nents
= dma_map_sg(buf
->dev
, sgt
->sgl
, sgt
->orig_nents
,
575 if (sgt
->nents
<= 0) {
576 pr_err("failed to map scatterlist\n");
581 contig_size
= vb2_dc_get_contiguous_size(sgt
);
582 if (contig_size
< size
) {
583 pr_err("contiguous mapping is too small %lu/%lu\n",
589 buf
->dma_addr
= sg_dma_address(sgt
->sgl
);
596 dma_unmap_sg(buf
->dev
, sgt
->sgl
, sgt
->orig_nents
, buf
->dma_dir
);
599 if (!vma_is_io(buf
->vma
))
600 vb2_dc_sgt_foreach_page(sgt
, put_page
);
607 if (pages
&& !vma_is_io(buf
->vma
))
609 put_page(pages
[--n_pages
]);
612 vb2_put_vma(buf
->vma
);
615 kfree(pages
); /* kfree is NULL-proof */
623 /*********************************************/
624 /* callbacks for DMABUF buffers */
625 /*********************************************/
627 static int vb2_dc_map_dmabuf(void *mem_priv
)
629 struct vb2_dc_buf
*buf
= mem_priv
;
630 struct sg_table
*sgt
;
631 unsigned long contig_size
;
633 if (WARN_ON(!buf
->db_attach
)) {
634 pr_err("trying to pin a non attached buffer\n");
638 if (WARN_ON(buf
->dma_sgt
)) {
639 pr_err("dmabuf buffer is already pinned\n");
643 /* get the associated scatterlist for this buffer */
644 sgt
= dma_buf_map_attachment(buf
->db_attach
, buf
->dma_dir
);
645 if (IS_ERR_OR_NULL(sgt
)) {
646 pr_err("Error getting dmabuf scatterlist\n");
650 /* checking if dmabuf is big enough to store contiguous chunk */
651 contig_size
= vb2_dc_get_contiguous_size(sgt
);
652 if (contig_size
< buf
->size
) {
653 pr_err("contiguous chunk is too small %lu/%lu b\n",
654 contig_size
, buf
->size
);
655 dma_buf_unmap_attachment(buf
->db_attach
, sgt
, buf
->dma_dir
);
659 buf
->dma_addr
= sg_dma_address(sgt
->sgl
);
665 static void vb2_dc_unmap_dmabuf(void *mem_priv
)
667 struct vb2_dc_buf
*buf
= mem_priv
;
668 struct sg_table
*sgt
= buf
->dma_sgt
;
670 if (WARN_ON(!buf
->db_attach
)) {
671 pr_err("trying to unpin a not attached buffer\n");
676 pr_err("dmabuf buffer is already unpinned\n");
680 dma_buf_unmap_attachment(buf
->db_attach
, sgt
, buf
->dma_dir
);
686 static void vb2_dc_detach_dmabuf(void *mem_priv
)
688 struct vb2_dc_buf
*buf
= mem_priv
;
690 /* if vb2 works correctly you should never detach mapped buffer */
691 if (WARN_ON(buf
->dma_addr
))
692 vb2_dc_unmap_dmabuf(buf
);
694 /* detach this attachment */
695 dma_buf_detach(buf
->db_attach
->dmabuf
, buf
->db_attach
);
699 static void *vb2_dc_attach_dmabuf(void *alloc_ctx
, struct dma_buf
*dbuf
,
700 unsigned long size
, int write
)
702 struct vb2_dc_conf
*conf
= alloc_ctx
;
703 struct vb2_dc_buf
*buf
;
704 struct dma_buf_attachment
*dba
;
706 if (dbuf
->size
< size
)
707 return ERR_PTR(-EFAULT
);
709 buf
= kzalloc(sizeof(*buf
), GFP_KERNEL
);
711 return ERR_PTR(-ENOMEM
);
713 buf
->dev
= conf
->dev
;
714 /* create attachment for the dmabuf with the user device */
715 dba
= dma_buf_attach(dbuf
, buf
->dev
);
717 pr_err("failed to attach dmabuf\n");
722 buf
->dma_dir
= write
? DMA_FROM_DEVICE
: DMA_TO_DEVICE
;
724 buf
->db_attach
= dba
;
729 /*********************************************/
730 /* DMA CONTIG exported functions */
731 /*********************************************/
733 const struct vb2_mem_ops vb2_dma_contig_memops
= {
734 .alloc
= vb2_dc_alloc
,
736 .get_dmabuf
= vb2_dc_get_dmabuf
,
737 .cookie
= vb2_dc_cookie
,
738 .vaddr
= vb2_dc_vaddr
,
740 .get_userptr
= vb2_dc_get_userptr
,
741 .put_userptr
= vb2_dc_put_userptr
,
742 .prepare
= vb2_dc_prepare
,
743 .finish
= vb2_dc_finish
,
744 .map_dmabuf
= vb2_dc_map_dmabuf
,
745 .unmap_dmabuf
= vb2_dc_unmap_dmabuf
,
746 .attach_dmabuf
= vb2_dc_attach_dmabuf
,
747 .detach_dmabuf
= vb2_dc_detach_dmabuf
,
748 .num_users
= vb2_dc_num_users
,
750 EXPORT_SYMBOL_GPL(vb2_dma_contig_memops
);
752 void *vb2_dma_contig_init_ctx(struct device
*dev
)
754 struct vb2_dc_conf
*conf
;
756 conf
= kzalloc(sizeof *conf
, GFP_KERNEL
);
758 return ERR_PTR(-ENOMEM
);
764 EXPORT_SYMBOL_GPL(vb2_dma_contig_init_ctx
);
766 void vb2_dma_contig_cleanup_ctx(void *alloc_ctx
)
770 EXPORT_SYMBOL_GPL(vb2_dma_contig_cleanup_ctx
);
772 MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2");
773 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
774 MODULE_LICENSE("GPL");