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
;
101 if (!buf
->vaddr
&& buf
->db_attach
)
102 buf
->vaddr
= dma_buf_vmap(buf
->db_attach
->dmabuf
);
107 static unsigned int vb2_dc_num_users(void *buf_priv
)
109 struct vb2_dc_buf
*buf
= buf_priv
;
111 return atomic_read(&buf
->refcount
);
114 static void vb2_dc_prepare(void *buf_priv
)
116 struct vb2_dc_buf
*buf
= buf_priv
;
117 struct sg_table
*sgt
= buf
->dma_sgt
;
119 /* DMABUF exporter will flush the cache for us */
120 if (!sgt
|| buf
->db_attach
)
123 dma_sync_sg_for_device(buf
->dev
, sgt
->sgl
, sgt
->nents
, buf
->dma_dir
);
126 static void vb2_dc_finish(void *buf_priv
)
128 struct vb2_dc_buf
*buf
= buf_priv
;
129 struct sg_table
*sgt
= buf
->dma_sgt
;
131 /* DMABUF exporter will flush the cache for us */
132 if (!sgt
|| buf
->db_attach
)
135 dma_sync_sg_for_cpu(buf
->dev
, sgt
->sgl
, sgt
->nents
, buf
->dma_dir
);
138 /*********************************************/
139 /* callbacks for MMAP buffers */
140 /*********************************************/
142 static void vb2_dc_put(void *buf_priv
)
144 struct vb2_dc_buf
*buf
= buf_priv
;
146 if (!atomic_dec_and_test(&buf
->refcount
))
150 sg_free_table(buf
->sgt_base
);
151 kfree(buf
->sgt_base
);
153 dma_free_coherent(buf
->dev
, buf
->size
, buf
->vaddr
, buf
->dma_addr
);
154 put_device(buf
->dev
);
158 static void *vb2_dc_alloc(void *alloc_ctx
, unsigned long size
,
159 enum dma_data_direction dma_dir
, gfp_t gfp_flags
)
161 struct vb2_dc_conf
*conf
= alloc_ctx
;
162 struct device
*dev
= conf
->dev
;
163 struct vb2_dc_buf
*buf
;
165 buf
= kzalloc(sizeof *buf
, GFP_KERNEL
);
167 return ERR_PTR(-ENOMEM
);
169 buf
->vaddr
= dma_alloc_coherent(dev
, size
, &buf
->dma_addr
,
170 GFP_KERNEL
| gfp_flags
);
172 dev_err(dev
, "dma_alloc_coherent of size %ld failed\n", size
);
174 return ERR_PTR(-ENOMEM
);
177 /* Prevent the device from being released while the buffer is used */
178 buf
->dev
= get_device(dev
);
180 buf
->dma_dir
= dma_dir
;
182 buf
->handler
.refcount
= &buf
->refcount
;
183 buf
->handler
.put
= vb2_dc_put
;
184 buf
->handler
.arg
= buf
;
186 atomic_inc(&buf
->refcount
);
191 static int vb2_dc_mmap(void *buf_priv
, struct vm_area_struct
*vma
)
193 struct vb2_dc_buf
*buf
= buf_priv
;
197 printk(KERN_ERR
"No buffer to map\n");
202 * dma_mmap_* uses vm_pgoff as in-buffer offset, but we want to
207 ret
= dma_mmap_coherent(buf
->dev
, vma
, buf
->vaddr
,
208 buf
->dma_addr
, buf
->size
);
211 pr_err("Remapping memory failed, error: %d\n", ret
);
215 vma
->vm_flags
|= VM_DONTEXPAND
| VM_DONTDUMP
;
216 vma
->vm_private_data
= &buf
->handler
;
217 vma
->vm_ops
= &vb2_common_vm_ops
;
219 vma
->vm_ops
->open(vma
);
221 pr_debug("%s: mapped dma addr 0x%08lx at 0x%08lx, size %ld\n",
222 __func__
, (unsigned long)buf
->dma_addr
, vma
->vm_start
,
228 /*********************************************/
229 /* DMABUF ops for exporters */
230 /*********************************************/
232 struct vb2_dc_attachment
{
234 enum dma_data_direction dma_dir
;
237 static int vb2_dc_dmabuf_ops_attach(struct dma_buf
*dbuf
, struct device
*dev
,
238 struct dma_buf_attachment
*dbuf_attach
)
240 struct vb2_dc_attachment
*attach
;
242 struct scatterlist
*rd
, *wr
;
243 struct sg_table
*sgt
;
244 struct vb2_dc_buf
*buf
= dbuf
->priv
;
247 attach
= kzalloc(sizeof(*attach
), GFP_KERNEL
);
252 /* Copy the buf->base_sgt scatter list to the attachment, as we can't
253 * map the same scatter list to multiple attachments at the same time.
255 ret
= sg_alloc_table(sgt
, buf
->sgt_base
->orig_nents
, GFP_KERNEL
);
261 rd
= buf
->sgt_base
->sgl
;
263 for (i
= 0; i
< sgt
->orig_nents
; ++i
) {
264 sg_set_page(wr
, sg_page(rd
), rd
->length
, rd
->offset
);
269 attach
->dma_dir
= DMA_NONE
;
270 dbuf_attach
->priv
= attach
;
275 static void vb2_dc_dmabuf_ops_detach(struct dma_buf
*dbuf
,
276 struct dma_buf_attachment
*db_attach
)
278 struct vb2_dc_attachment
*attach
= db_attach
->priv
;
279 struct sg_table
*sgt
;
286 /* release the scatterlist cache */
287 if (attach
->dma_dir
!= DMA_NONE
)
288 dma_unmap_sg(db_attach
->dev
, sgt
->sgl
, sgt
->orig_nents
,
292 db_attach
->priv
= NULL
;
295 static struct sg_table
*vb2_dc_dmabuf_ops_map(
296 struct dma_buf_attachment
*db_attach
, enum dma_data_direction dma_dir
)
298 struct vb2_dc_attachment
*attach
= db_attach
->priv
;
299 /* stealing dmabuf mutex to serialize map/unmap operations */
300 struct mutex
*lock
= &db_attach
->dmabuf
->lock
;
301 struct sg_table
*sgt
;
306 /* return previously mapped sg table */
307 if (attach
->dma_dir
== dma_dir
) {
312 /* release any previous cache */
313 if (attach
->dma_dir
!= DMA_NONE
) {
314 dma_unmap_sg(db_attach
->dev
, sgt
->sgl
, sgt
->orig_nents
,
316 attach
->dma_dir
= DMA_NONE
;
319 /* mapping to the client with new direction */
320 sgt
->nents
= dma_map_sg(db_attach
->dev
, sgt
->sgl
, sgt
->orig_nents
,
323 pr_err("failed to map scatterlist\n");
325 return ERR_PTR(-EIO
);
328 attach
->dma_dir
= dma_dir
;
335 static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment
*db_attach
,
336 struct sg_table
*sgt
, enum dma_data_direction dma_dir
)
338 /* nothing to be done here */
341 static void vb2_dc_dmabuf_ops_release(struct dma_buf
*dbuf
)
343 /* drop reference obtained in vb2_dc_get_dmabuf */
344 vb2_dc_put(dbuf
->priv
);
347 static void *vb2_dc_dmabuf_ops_kmap(struct dma_buf
*dbuf
, unsigned long pgnum
)
349 struct vb2_dc_buf
*buf
= dbuf
->priv
;
351 return buf
->vaddr
+ pgnum
* PAGE_SIZE
;
354 static void *vb2_dc_dmabuf_ops_vmap(struct dma_buf
*dbuf
)
356 struct vb2_dc_buf
*buf
= dbuf
->priv
;
361 static int vb2_dc_dmabuf_ops_mmap(struct dma_buf
*dbuf
,
362 struct vm_area_struct
*vma
)
364 return vb2_dc_mmap(dbuf
->priv
, vma
);
367 static struct dma_buf_ops vb2_dc_dmabuf_ops
= {
368 .attach
= vb2_dc_dmabuf_ops_attach
,
369 .detach
= vb2_dc_dmabuf_ops_detach
,
370 .map_dma_buf
= vb2_dc_dmabuf_ops_map
,
371 .unmap_dma_buf
= vb2_dc_dmabuf_ops_unmap
,
372 .kmap
= vb2_dc_dmabuf_ops_kmap
,
373 .kmap_atomic
= vb2_dc_dmabuf_ops_kmap
,
374 .vmap
= vb2_dc_dmabuf_ops_vmap
,
375 .mmap
= vb2_dc_dmabuf_ops_mmap
,
376 .release
= vb2_dc_dmabuf_ops_release
,
379 static struct sg_table
*vb2_dc_get_base_sgt(struct vb2_dc_buf
*buf
)
382 struct sg_table
*sgt
;
384 sgt
= kmalloc(sizeof(*sgt
), GFP_KERNEL
);
386 dev_err(buf
->dev
, "failed to alloc sg table\n");
390 ret
= dma_get_sgtable(buf
->dev
, sgt
, buf
->vaddr
, buf
->dma_addr
,
393 dev_err(buf
->dev
, "failed to get scatterlist from DMA API\n");
401 static struct dma_buf
*vb2_dc_get_dmabuf(void *buf_priv
, unsigned long flags
)
403 struct vb2_dc_buf
*buf
= buf_priv
;
404 struct dma_buf
*dbuf
;
405 DEFINE_DMA_BUF_EXPORT_INFO(exp_info
);
407 exp_info
.ops
= &vb2_dc_dmabuf_ops
;
408 exp_info
.size
= buf
->size
;
409 exp_info
.flags
= flags
;
413 buf
->sgt_base
= vb2_dc_get_base_sgt(buf
);
415 if (WARN_ON(!buf
->sgt_base
))
418 dbuf
= dma_buf_export(&exp_info
);
422 /* dmabuf keeps reference to vb2 buffer */
423 atomic_inc(&buf
->refcount
);
428 /*********************************************/
429 /* callbacks for USERPTR buffers */
430 /*********************************************/
432 static inline int vma_is_io(struct vm_area_struct
*vma
)
434 return !!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
));
437 static int vb2_dc_get_user_pfn(unsigned long start
, int n_pages
,
438 struct vm_area_struct
*vma
, unsigned long *res
)
440 unsigned long pfn
, start_pfn
, prev_pfn
;
447 ret
= follow_pfn(vma
, start
, &pfn
);
454 for (i
= 1; i
< n_pages
; ++i
, start
+= PAGE_SIZE
) {
456 ret
= follow_pfn(vma
, start
, &pfn
);
459 pr_err("no page for address %lu\n", start
);
462 if (pfn
!= prev_pfn
+ 1)
470 static int vb2_dc_get_user_pages(unsigned long start
, struct page
**pages
,
471 int n_pages
, struct vm_area_struct
*vma
,
472 enum dma_data_direction dma_dir
)
474 if (vma_is_io(vma
)) {
477 for (i
= 0; i
< n_pages
; ++i
, start
+= PAGE_SIZE
) {
479 int ret
= follow_pfn(vma
, start
, &pfn
);
485 pr_err("no page for address %lu\n", start
);
488 pages
[i
] = pfn_to_page(pfn
);
493 n
= get_user_pages(current
, current
->mm
, start
& PAGE_MASK
,
494 n_pages
, dma_dir
== DMA_FROM_DEVICE
, 1, pages
, NULL
);
495 /* negative error means that no page was pinned */
498 pr_err("got only %d of %d user pages\n", n
, n_pages
);
500 put_page(pages
[--n
]);
508 static void vb2_dc_put_dirty_page(struct page
*page
)
510 set_page_dirty_lock(page
);
514 static void vb2_dc_put_userptr(void *buf_priv
)
516 struct vb2_dc_buf
*buf
= buf_priv
;
517 struct sg_table
*sgt
= buf
->dma_sgt
;
520 DEFINE_DMA_ATTRS(attrs
);
522 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC
, &attrs
);
524 * No need to sync to CPU, it's already synced to the CPU
525 * since the finish() memop will have been called before this.
527 dma_unmap_sg_attrs(buf
->dev
, sgt
->sgl
, sgt
->orig_nents
,
528 buf
->dma_dir
, &attrs
);
529 if (!vma_is_io(buf
->vma
))
530 vb2_dc_sgt_foreach_page(sgt
, vb2_dc_put_dirty_page
);
535 vb2_put_vma(buf
->vma
);
540 * For some kind of reserved memory there might be no struct page available,
541 * so all that can be done to support such 'pages' is to try to convert
542 * pfn to dma address or at the last resort just assume that
543 * dma address == physical address (like it has been assumed in earlier version
544 * of videobuf2-dma-contig
547 #ifdef __arch_pfn_to_dma
548 static inline dma_addr_t
vb2_dc_pfn_to_dma(struct device
*dev
, unsigned long pfn
)
550 return (dma_addr_t
)__arch_pfn_to_dma(dev
, pfn
);
552 #elif defined(__pfn_to_bus)
553 static inline dma_addr_t
vb2_dc_pfn_to_dma(struct device
*dev
, unsigned long pfn
)
555 return (dma_addr_t
)__pfn_to_bus(pfn
);
557 #elif defined(__pfn_to_phys)
558 static inline dma_addr_t
vb2_dc_pfn_to_dma(struct device
*dev
, unsigned long pfn
)
560 return (dma_addr_t
)__pfn_to_phys(pfn
);
563 static inline dma_addr_t
vb2_dc_pfn_to_dma(struct device
*dev
, unsigned long pfn
)
565 /* really, we cannot do anything better at this point */
566 return (dma_addr_t
)(pfn
) << PAGE_SHIFT
;
570 static void *vb2_dc_get_userptr(void *alloc_ctx
, unsigned long vaddr
,
571 unsigned long size
, enum dma_data_direction dma_dir
)
573 struct vb2_dc_conf
*conf
= alloc_ctx
;
574 struct vb2_dc_buf
*buf
;
577 unsigned long offset
;
581 struct vm_area_struct
*vma
;
582 struct sg_table
*sgt
;
583 unsigned long contig_size
;
584 unsigned long dma_align
= dma_get_cache_alignment();
585 DEFINE_DMA_ATTRS(attrs
);
587 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC
, &attrs
);
589 /* Only cache aligned DMA transfers are reliable */
590 if (!IS_ALIGNED(vaddr
| size
, dma_align
)) {
591 pr_debug("user data must be aligned to %lu bytes\n", dma_align
);
592 return ERR_PTR(-EINVAL
);
596 pr_debug("size is zero\n");
597 return ERR_PTR(-EINVAL
);
600 buf
= kzalloc(sizeof *buf
, GFP_KERNEL
);
602 return ERR_PTR(-ENOMEM
);
604 buf
->dev
= conf
->dev
;
605 buf
->dma_dir
= dma_dir
;
607 start
= vaddr
& PAGE_MASK
;
608 offset
= vaddr
& ~PAGE_MASK
;
609 end
= PAGE_ALIGN(vaddr
+ size
);
610 n_pages
= (end
- start
) >> PAGE_SHIFT
;
612 pages
= kmalloc(n_pages
* sizeof(pages
[0]), GFP_KERNEL
);
615 pr_err("failed to allocate pages table\n");
619 /* current->mm->mmap_sem is taken by videobuf2 core */
620 vma
= find_vma(current
->mm
, vaddr
);
622 pr_err("no vma for address %lu\n", vaddr
);
627 if (vma
->vm_end
< vaddr
+ size
) {
628 pr_err("vma at %lu is too small for %lu bytes\n", vaddr
, size
);
633 buf
->vma
= vb2_get_vma(vma
);
635 pr_err("failed to copy vma\n");
640 /* extract page list from userspace mapping */
641 ret
= vb2_dc_get_user_pages(start
, pages
, n_pages
, vma
, dma_dir
);
644 if (vb2_dc_get_user_pfn(start
, n_pages
, vma
, &pfn
) == 0) {
645 buf
->dma_addr
= vb2_dc_pfn_to_dma(buf
->dev
, pfn
);
651 pr_err("failed to get user pages\n");
655 sgt
= kzalloc(sizeof(*sgt
), GFP_KERNEL
);
657 pr_err("failed to allocate sg table\n");
659 goto fail_get_user_pages
;
662 ret
= sg_alloc_table_from_pages(sgt
, pages
, n_pages
,
663 offset
, size
, GFP_KERNEL
);
665 pr_err("failed to initialize sg table\n");
669 /* pages are no longer needed */
674 * No need to sync to the device, this will happen later when the
675 * prepare() memop is called.
677 sgt
->nents
= dma_map_sg_attrs(buf
->dev
, sgt
->sgl
, sgt
->orig_nents
,
678 buf
->dma_dir
, &attrs
);
679 if (sgt
->nents
<= 0) {
680 pr_err("failed to map scatterlist\n");
685 contig_size
= vb2_dc_get_contiguous_size(sgt
);
686 if (contig_size
< size
) {
687 pr_err("contiguous mapping is too small %lu/%lu\n",
693 buf
->dma_addr
= sg_dma_address(sgt
->sgl
);
700 dma_unmap_sg_attrs(buf
->dev
, sgt
->sgl
, sgt
->orig_nents
,
701 buf
->dma_dir
, &attrs
);
704 if (!vma_is_io(buf
->vma
))
705 vb2_dc_sgt_foreach_page(sgt
, put_page
);
712 if (pages
&& !vma_is_io(buf
->vma
))
714 put_page(pages
[--n_pages
]);
717 vb2_put_vma(buf
->vma
);
720 kfree(pages
); /* kfree is NULL-proof */
728 /*********************************************/
729 /* callbacks for DMABUF buffers */
730 /*********************************************/
732 static int vb2_dc_map_dmabuf(void *mem_priv
)
734 struct vb2_dc_buf
*buf
= mem_priv
;
735 struct sg_table
*sgt
;
736 unsigned long contig_size
;
738 if (WARN_ON(!buf
->db_attach
)) {
739 pr_err("trying to pin a non attached buffer\n");
743 if (WARN_ON(buf
->dma_sgt
)) {
744 pr_err("dmabuf buffer is already pinned\n");
748 /* get the associated scatterlist for this buffer */
749 sgt
= dma_buf_map_attachment(buf
->db_attach
, buf
->dma_dir
);
751 pr_err("Error getting dmabuf scatterlist\n");
755 /* checking if dmabuf is big enough to store contiguous chunk */
756 contig_size
= vb2_dc_get_contiguous_size(sgt
);
757 if (contig_size
< buf
->size
) {
758 pr_err("contiguous chunk is too small %lu/%lu b\n",
759 contig_size
, buf
->size
);
760 dma_buf_unmap_attachment(buf
->db_attach
, sgt
, buf
->dma_dir
);
764 buf
->dma_addr
= sg_dma_address(sgt
->sgl
);
771 static void vb2_dc_unmap_dmabuf(void *mem_priv
)
773 struct vb2_dc_buf
*buf
= mem_priv
;
774 struct sg_table
*sgt
= buf
->dma_sgt
;
776 if (WARN_ON(!buf
->db_attach
)) {
777 pr_err("trying to unpin a not attached buffer\n");
782 pr_err("dmabuf buffer is already unpinned\n");
787 dma_buf_vunmap(buf
->db_attach
->dmabuf
, buf
->vaddr
);
790 dma_buf_unmap_attachment(buf
->db_attach
, sgt
, buf
->dma_dir
);
796 static void vb2_dc_detach_dmabuf(void *mem_priv
)
798 struct vb2_dc_buf
*buf
= mem_priv
;
800 /* if vb2 works correctly you should never detach mapped buffer */
801 if (WARN_ON(buf
->dma_addr
))
802 vb2_dc_unmap_dmabuf(buf
);
804 /* detach this attachment */
805 dma_buf_detach(buf
->db_attach
->dmabuf
, buf
->db_attach
);
809 static void *vb2_dc_attach_dmabuf(void *alloc_ctx
, struct dma_buf
*dbuf
,
810 unsigned long size
, enum dma_data_direction dma_dir
)
812 struct vb2_dc_conf
*conf
= alloc_ctx
;
813 struct vb2_dc_buf
*buf
;
814 struct dma_buf_attachment
*dba
;
816 if (dbuf
->size
< size
)
817 return ERR_PTR(-EFAULT
);
819 buf
= kzalloc(sizeof(*buf
), GFP_KERNEL
);
821 return ERR_PTR(-ENOMEM
);
823 buf
->dev
= conf
->dev
;
824 /* create attachment for the dmabuf with the user device */
825 dba
= dma_buf_attach(dbuf
, buf
->dev
);
827 pr_err("failed to attach dmabuf\n");
832 buf
->dma_dir
= dma_dir
;
834 buf
->db_attach
= dba
;
839 /*********************************************/
840 /* DMA CONTIG exported functions */
841 /*********************************************/
843 const struct vb2_mem_ops vb2_dma_contig_memops
= {
844 .alloc
= vb2_dc_alloc
,
846 .get_dmabuf
= vb2_dc_get_dmabuf
,
847 .cookie
= vb2_dc_cookie
,
848 .vaddr
= vb2_dc_vaddr
,
850 .get_userptr
= vb2_dc_get_userptr
,
851 .put_userptr
= vb2_dc_put_userptr
,
852 .prepare
= vb2_dc_prepare
,
853 .finish
= vb2_dc_finish
,
854 .map_dmabuf
= vb2_dc_map_dmabuf
,
855 .unmap_dmabuf
= vb2_dc_unmap_dmabuf
,
856 .attach_dmabuf
= vb2_dc_attach_dmabuf
,
857 .detach_dmabuf
= vb2_dc_detach_dmabuf
,
858 .num_users
= vb2_dc_num_users
,
860 EXPORT_SYMBOL_GPL(vb2_dma_contig_memops
);
862 void *vb2_dma_contig_init_ctx(struct device
*dev
)
864 struct vb2_dc_conf
*conf
;
866 conf
= kzalloc(sizeof *conf
, GFP_KERNEL
);
868 return ERR_PTR(-ENOMEM
);
874 EXPORT_SYMBOL_GPL(vb2_dma_contig_init_ctx
);
876 void vb2_dma_contig_cleanup_ctx(void *alloc_ctx
)
878 if (!IS_ERR_OR_NULL(alloc_ctx
))
881 EXPORT_SYMBOL_GPL(vb2_dma_contig_cleanup_ctx
);
883 MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2");
884 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
885 MODULE_LICENSE("GPL");