2 * videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2
4 * Copyright (C) 2010 Samsung Electronics
6 * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.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/module.h>
15 #include <linux/scatterlist.h>
16 #include <linux/sched.h>
17 #include <linux/slab.h>
18 #include <linux/vmalloc.h>
20 #include <media/videobuf2-core.h>
21 #include <media/videobuf2-memops.h>
22 #include <media/videobuf2-dma-sg.h>
25 module_param(debug
, int, 0644);
27 #define dprintk(level, fmt, arg...) \
30 printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg); \
33 struct vb2_dma_sg_conf
{
37 struct vb2_dma_sg_buf
{
42 enum dma_data_direction dma_dir
;
43 struct sg_table sg_table
;
45 * This will point to sg_table when used with the MMAP or USERPTR
46 * memory model, and to the dma_buf sglist when used with the
47 * DMABUF memory model.
49 struct sg_table
*dma_sgt
;
51 unsigned int num_pages
;
53 struct vb2_vmarea_handler handler
;
54 struct vm_area_struct
*vma
;
56 struct dma_buf_attachment
*db_attach
;
59 static void vb2_dma_sg_put(void *buf_priv
);
61 static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf
*buf
,
64 unsigned int last_page
= 0;
72 order
= get_order(size
);
73 /* Dont over allocate*/
74 if ((PAGE_SIZE
<< order
) > size
)
79 pages
= alloc_pages(GFP_KERNEL
| __GFP_ZERO
|
80 __GFP_NOWARN
| gfp_flags
, order
);
86 __free_page(buf
->pages
[last_page
]);
92 split_page(pages
, order
);
93 for (i
= 0; i
< (1 << order
); i
++)
94 buf
->pages
[last_page
++] = &pages
[i
];
96 size
-= PAGE_SIZE
<< order
;
102 static void *vb2_dma_sg_alloc(void *alloc_ctx
, unsigned long size
,
103 enum dma_data_direction dma_dir
, gfp_t gfp_flags
)
105 struct vb2_dma_sg_conf
*conf
= alloc_ctx
;
106 struct vb2_dma_sg_buf
*buf
;
107 struct sg_table
*sgt
;
110 DEFINE_DMA_ATTRS(attrs
);
112 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC
, &attrs
);
114 if (WARN_ON(alloc_ctx
== NULL
))
116 buf
= kzalloc(sizeof *buf
, GFP_KERNEL
);
121 buf
->dma_dir
= dma_dir
;
124 /* size is already page aligned */
125 buf
->num_pages
= size
>> PAGE_SHIFT
;
126 buf
->dma_sgt
= &buf
->sg_table
;
128 buf
->pages
= kzalloc(buf
->num_pages
* sizeof(struct page
*),
131 goto fail_pages_array_alloc
;
133 ret
= vb2_dma_sg_alloc_compacted(buf
, gfp_flags
);
135 goto fail_pages_alloc
;
137 ret
= sg_alloc_table_from_pages(buf
->dma_sgt
, buf
->pages
,
138 buf
->num_pages
, 0, size
, GFP_KERNEL
);
140 goto fail_table_alloc
;
142 /* Prevent the device from being released while the buffer is used */
143 buf
->dev
= get_device(conf
->dev
);
145 sgt
= &buf
->sg_table
;
147 * No need to sync to the device, this will happen later when the
148 * prepare() memop is called.
150 if (dma_map_sg_attrs(buf
->dev
, sgt
->sgl
, sgt
->nents
,
151 buf
->dma_dir
, &attrs
) == 0)
154 buf
->handler
.refcount
= &buf
->refcount
;
155 buf
->handler
.put
= vb2_dma_sg_put
;
156 buf
->handler
.arg
= buf
;
158 atomic_inc(&buf
->refcount
);
160 dprintk(1, "%s: Allocated buffer of %d pages\n",
161 __func__
, buf
->num_pages
);
165 put_device(buf
->dev
);
166 sg_free_table(buf
->dma_sgt
);
168 num_pages
= buf
->num_pages
;
170 __free_page(buf
->pages
[num_pages
]);
173 fail_pages_array_alloc
:
178 static void vb2_dma_sg_put(void *buf_priv
)
180 struct vb2_dma_sg_buf
*buf
= buf_priv
;
181 struct sg_table
*sgt
= &buf
->sg_table
;
182 int i
= buf
->num_pages
;
184 if (atomic_dec_and_test(&buf
->refcount
)) {
185 DEFINE_DMA_ATTRS(attrs
);
187 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC
, &attrs
);
188 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__
,
190 dma_unmap_sg_attrs(buf
->dev
, sgt
->sgl
, sgt
->nents
,
191 buf
->dma_dir
, &attrs
);
193 vm_unmap_ram(buf
->vaddr
, buf
->num_pages
);
194 sg_free_table(buf
->dma_sgt
);
196 __free_page(buf
->pages
[i
]);
198 put_device(buf
->dev
);
203 static void vb2_dma_sg_prepare(void *buf_priv
)
205 struct vb2_dma_sg_buf
*buf
= buf_priv
;
206 struct sg_table
*sgt
= buf
->dma_sgt
;
208 /* DMABUF exporter will flush the cache for us */
212 dma_sync_sg_for_device(buf
->dev
, sgt
->sgl
, sgt
->nents
, buf
->dma_dir
);
215 static void vb2_dma_sg_finish(void *buf_priv
)
217 struct vb2_dma_sg_buf
*buf
= buf_priv
;
218 struct sg_table
*sgt
= buf
->dma_sgt
;
220 /* DMABUF exporter will flush the cache for us */
224 dma_sync_sg_for_cpu(buf
->dev
, sgt
->sgl
, sgt
->nents
, buf
->dma_dir
);
227 static inline int vma_is_io(struct vm_area_struct
*vma
)
229 return !!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
));
232 static void *vb2_dma_sg_get_userptr(void *alloc_ctx
, unsigned long vaddr
,
234 enum dma_data_direction dma_dir
)
236 struct vb2_dma_sg_conf
*conf
= alloc_ctx
;
237 struct vb2_dma_sg_buf
*buf
;
238 unsigned long first
, last
;
239 int num_pages_from_user
;
240 struct vm_area_struct
*vma
;
241 struct sg_table
*sgt
;
242 DEFINE_DMA_ATTRS(attrs
);
244 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC
, &attrs
);
246 buf
= kzalloc(sizeof *buf
, GFP_KERNEL
);
251 buf
->dev
= conf
->dev
;
252 buf
->dma_dir
= dma_dir
;
253 buf
->offset
= vaddr
& ~PAGE_MASK
;
255 buf
->dma_sgt
= &buf
->sg_table
;
257 first
= (vaddr
& PAGE_MASK
) >> PAGE_SHIFT
;
258 last
= ((vaddr
+ size
- 1) & PAGE_MASK
) >> PAGE_SHIFT
;
259 buf
->num_pages
= last
- first
+ 1;
261 buf
->pages
= kzalloc(buf
->num_pages
* sizeof(struct page
*),
264 goto userptr_fail_alloc_pages
;
266 down_read(¤t
->mm
->mmap_sem
);
267 vma
= find_vma(current
->mm
, vaddr
);
269 dprintk(1, "no vma for address %lu\n", vaddr
);
270 goto userptr_fail_find_vma
;
273 if (vma
->vm_end
< vaddr
+ size
) {
274 dprintk(1, "vma at %lu is too small for %lu bytes\n",
276 goto userptr_fail_find_vma
;
279 buf
->vma
= vb2_get_vma(vma
);
281 dprintk(1, "failed to copy vma\n");
282 goto userptr_fail_find_vma
;
285 if (vma_is_io(buf
->vma
)) {
286 for (num_pages_from_user
= 0;
287 num_pages_from_user
< buf
->num_pages
;
288 ++num_pages_from_user
, vaddr
+= PAGE_SIZE
) {
291 if (follow_pfn(vma
, vaddr
, &pfn
)) {
292 dprintk(1, "no page for address %lu\n", vaddr
);
295 buf
->pages
[num_pages_from_user
] = pfn_to_page(pfn
);
298 num_pages_from_user
= get_user_pages(current
, current
->mm
,
301 buf
->dma_dir
== DMA_FROM_DEVICE
,
305 up_read(¤t
->mm
->mmap_sem
);
307 if (num_pages_from_user
!= buf
->num_pages
)
308 goto userptr_fail_get_user_pages
;
310 if (sg_alloc_table_from_pages(buf
->dma_sgt
, buf
->pages
,
311 buf
->num_pages
, buf
->offset
, size
, 0))
312 goto userptr_fail_alloc_table_from_pages
;
314 sgt
= &buf
->sg_table
;
316 * No need to sync to the device, this will happen later when the
317 * prepare() memop is called.
319 if (dma_map_sg_attrs(buf
->dev
, sgt
->sgl
, sgt
->nents
,
320 buf
->dma_dir
, &attrs
) == 0)
321 goto userptr_fail_map
;
325 sg_free_table(&buf
->sg_table
);
326 userptr_fail_alloc_table_from_pages
:
327 userptr_fail_get_user_pages
:
328 dprintk(1, "get_user_pages requested/got: %d/%d]\n",
329 buf
->num_pages
, num_pages_from_user
);
330 if (!vma_is_io(buf
->vma
))
331 while (--num_pages_from_user
>= 0)
332 put_page(buf
->pages
[num_pages_from_user
]);
333 down_read(¤t
->mm
->mmap_sem
);
334 vb2_put_vma(buf
->vma
);
335 userptr_fail_find_vma
:
336 up_read(¤t
->mm
->mmap_sem
);
338 userptr_fail_alloc_pages
:
344 * @put_userptr: inform the allocator that a USERPTR buffer will no longer
347 static void vb2_dma_sg_put_userptr(void *buf_priv
)
349 struct vb2_dma_sg_buf
*buf
= buf_priv
;
350 struct sg_table
*sgt
= &buf
->sg_table
;
351 int i
= buf
->num_pages
;
352 DEFINE_DMA_ATTRS(attrs
);
354 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC
, &attrs
);
356 dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
357 __func__
, buf
->num_pages
);
358 dma_unmap_sg_attrs(buf
->dev
, sgt
->sgl
, sgt
->nents
, buf
->dma_dir
, &attrs
);
360 vm_unmap_ram(buf
->vaddr
, buf
->num_pages
);
361 sg_free_table(buf
->dma_sgt
);
363 if (buf
->dma_dir
== DMA_FROM_DEVICE
)
364 set_page_dirty_lock(buf
->pages
[i
]);
365 if (!vma_is_io(buf
->vma
))
366 put_page(buf
->pages
[i
]);
369 down_read(¤t
->mm
->mmap_sem
);
370 vb2_put_vma(buf
->vma
);
371 up_read(¤t
->mm
->mmap_sem
);
375 static void *vb2_dma_sg_vaddr(void *buf_priv
)
377 struct vb2_dma_sg_buf
*buf
= buf_priv
;
383 buf
->vaddr
= dma_buf_vmap(buf
->db_attach
->dmabuf
);
385 buf
->vaddr
= vm_map_ram(buf
->pages
,
386 buf
->num_pages
, -1, PAGE_KERNEL
);
389 /* add offset in case userptr is not page-aligned */
390 return buf
->vaddr
? buf
->vaddr
+ buf
->offset
: NULL
;
393 static unsigned int vb2_dma_sg_num_users(void *buf_priv
)
395 struct vb2_dma_sg_buf
*buf
= buf_priv
;
397 return atomic_read(&buf
->refcount
);
400 static int vb2_dma_sg_mmap(void *buf_priv
, struct vm_area_struct
*vma
)
402 struct vb2_dma_sg_buf
*buf
= buf_priv
;
403 unsigned long uaddr
= vma
->vm_start
;
404 unsigned long usize
= vma
->vm_end
- vma
->vm_start
;
408 printk(KERN_ERR
"No memory to map\n");
415 ret
= vm_insert_page(vma
, uaddr
, buf
->pages
[i
++]);
417 printk(KERN_ERR
"Remapping memory, error: %d\n", ret
);
427 * Use common vm_area operations to track buffer refcount.
429 vma
->vm_private_data
= &buf
->handler
;
430 vma
->vm_ops
= &vb2_common_vm_ops
;
432 vma
->vm_ops
->open(vma
);
437 /*********************************************/
438 /* DMABUF ops for exporters */
439 /*********************************************/
441 struct vb2_dma_sg_attachment
{
443 enum dma_data_direction dma_dir
;
446 static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf
*dbuf
, struct device
*dev
,
447 struct dma_buf_attachment
*dbuf_attach
)
449 struct vb2_dma_sg_attachment
*attach
;
451 struct scatterlist
*rd
, *wr
;
452 struct sg_table
*sgt
;
453 struct vb2_dma_sg_buf
*buf
= dbuf
->priv
;
456 attach
= kzalloc(sizeof(*attach
), GFP_KERNEL
);
461 /* Copy the buf->base_sgt scatter list to the attachment, as we can't
462 * map the same scatter list to multiple attachments at the same time.
464 ret
= sg_alloc_table(sgt
, buf
->dma_sgt
->orig_nents
, GFP_KERNEL
);
470 rd
= buf
->dma_sgt
->sgl
;
472 for (i
= 0; i
< sgt
->orig_nents
; ++i
) {
473 sg_set_page(wr
, sg_page(rd
), rd
->length
, rd
->offset
);
478 attach
->dma_dir
= DMA_NONE
;
479 dbuf_attach
->priv
= attach
;
484 static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf
*dbuf
,
485 struct dma_buf_attachment
*db_attach
)
487 struct vb2_dma_sg_attachment
*attach
= db_attach
->priv
;
488 struct sg_table
*sgt
;
495 /* release the scatterlist cache */
496 if (attach
->dma_dir
!= DMA_NONE
)
497 dma_unmap_sg(db_attach
->dev
, sgt
->sgl
, sgt
->orig_nents
,
501 db_attach
->priv
= NULL
;
504 static struct sg_table
*vb2_dma_sg_dmabuf_ops_map(
505 struct dma_buf_attachment
*db_attach
, enum dma_data_direction dma_dir
)
507 struct vb2_dma_sg_attachment
*attach
= db_attach
->priv
;
508 /* stealing dmabuf mutex to serialize map/unmap operations */
509 struct mutex
*lock
= &db_attach
->dmabuf
->lock
;
510 struct sg_table
*sgt
;
516 /* return previously mapped sg table */
517 if (attach
->dma_dir
== dma_dir
) {
522 /* release any previous cache */
523 if (attach
->dma_dir
!= DMA_NONE
) {
524 dma_unmap_sg(db_attach
->dev
, sgt
->sgl
, sgt
->orig_nents
,
526 attach
->dma_dir
= DMA_NONE
;
529 /* mapping to the client with new direction */
530 ret
= dma_map_sg(db_attach
->dev
, sgt
->sgl
, sgt
->orig_nents
, dma_dir
);
532 pr_err("failed to map scatterlist\n");
534 return ERR_PTR(-EIO
);
537 attach
->dma_dir
= dma_dir
;
544 static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment
*db_attach
,
545 struct sg_table
*sgt
, enum dma_data_direction dma_dir
)
547 /* nothing to be done here */
550 static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf
*dbuf
)
552 /* drop reference obtained in vb2_dma_sg_get_dmabuf */
553 vb2_dma_sg_put(dbuf
->priv
);
556 static void *vb2_dma_sg_dmabuf_ops_kmap(struct dma_buf
*dbuf
, unsigned long pgnum
)
558 struct vb2_dma_sg_buf
*buf
= dbuf
->priv
;
560 return buf
->vaddr
? buf
->vaddr
+ pgnum
* PAGE_SIZE
: NULL
;
563 static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf
*dbuf
)
565 struct vb2_dma_sg_buf
*buf
= dbuf
->priv
;
567 return vb2_dma_sg_vaddr(buf
);
570 static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf
*dbuf
,
571 struct vm_area_struct
*vma
)
573 return vb2_dma_sg_mmap(dbuf
->priv
, vma
);
576 static struct dma_buf_ops vb2_dma_sg_dmabuf_ops
= {
577 .attach
= vb2_dma_sg_dmabuf_ops_attach
,
578 .detach
= vb2_dma_sg_dmabuf_ops_detach
,
579 .map_dma_buf
= vb2_dma_sg_dmabuf_ops_map
,
580 .unmap_dma_buf
= vb2_dma_sg_dmabuf_ops_unmap
,
581 .kmap
= vb2_dma_sg_dmabuf_ops_kmap
,
582 .kmap_atomic
= vb2_dma_sg_dmabuf_ops_kmap
,
583 .vmap
= vb2_dma_sg_dmabuf_ops_vmap
,
584 .mmap
= vb2_dma_sg_dmabuf_ops_mmap
,
585 .release
= vb2_dma_sg_dmabuf_ops_release
,
588 static struct dma_buf
*vb2_dma_sg_get_dmabuf(void *buf_priv
, unsigned long flags
)
590 struct vb2_dma_sg_buf
*buf
= buf_priv
;
591 struct dma_buf
*dbuf
;
592 DEFINE_DMA_BUF_EXPORT_INFO(exp_info
);
594 exp_info
.ops
= &vb2_dma_sg_dmabuf_ops
;
595 exp_info
.size
= buf
->size
;
596 exp_info
.flags
= flags
;
599 if (WARN_ON(!buf
->dma_sgt
))
602 dbuf
= dma_buf_export(&exp_info
);
606 /* dmabuf keeps reference to vb2 buffer */
607 atomic_inc(&buf
->refcount
);
612 /*********************************************/
613 /* callbacks for DMABUF buffers */
614 /*********************************************/
616 static int vb2_dma_sg_map_dmabuf(void *mem_priv
)
618 struct vb2_dma_sg_buf
*buf
= mem_priv
;
619 struct sg_table
*sgt
;
621 if (WARN_ON(!buf
->db_attach
)) {
622 pr_err("trying to pin a non attached buffer\n");
626 if (WARN_ON(buf
->dma_sgt
)) {
627 pr_err("dmabuf buffer is already pinned\n");
631 /* get the associated scatterlist for this buffer */
632 sgt
= dma_buf_map_attachment(buf
->db_attach
, buf
->dma_dir
);
634 pr_err("Error getting dmabuf scatterlist\n");
644 static void vb2_dma_sg_unmap_dmabuf(void *mem_priv
)
646 struct vb2_dma_sg_buf
*buf
= mem_priv
;
647 struct sg_table
*sgt
= buf
->dma_sgt
;
649 if (WARN_ON(!buf
->db_attach
)) {
650 pr_err("trying to unpin a not attached buffer\n");
655 pr_err("dmabuf buffer is already unpinned\n");
660 dma_buf_vunmap(buf
->db_attach
->dmabuf
, buf
->vaddr
);
663 dma_buf_unmap_attachment(buf
->db_attach
, sgt
, buf
->dma_dir
);
668 static void vb2_dma_sg_detach_dmabuf(void *mem_priv
)
670 struct vb2_dma_sg_buf
*buf
= mem_priv
;
672 /* if vb2 works correctly you should never detach mapped buffer */
673 if (WARN_ON(buf
->dma_sgt
))
674 vb2_dma_sg_unmap_dmabuf(buf
);
676 /* detach this attachment */
677 dma_buf_detach(buf
->db_attach
->dmabuf
, buf
->db_attach
);
681 static void *vb2_dma_sg_attach_dmabuf(void *alloc_ctx
, struct dma_buf
*dbuf
,
682 unsigned long size
, enum dma_data_direction dma_dir
)
684 struct vb2_dma_sg_conf
*conf
= alloc_ctx
;
685 struct vb2_dma_sg_buf
*buf
;
686 struct dma_buf_attachment
*dba
;
688 if (dbuf
->size
< size
)
689 return ERR_PTR(-EFAULT
);
691 buf
= kzalloc(sizeof(*buf
), GFP_KERNEL
);
693 return ERR_PTR(-ENOMEM
);
695 buf
->dev
= conf
->dev
;
696 /* create attachment for the dmabuf with the user device */
697 dba
= dma_buf_attach(dbuf
, buf
->dev
);
699 pr_err("failed to attach dmabuf\n");
704 buf
->dma_dir
= dma_dir
;
706 buf
->db_attach
= dba
;
711 static void *vb2_dma_sg_cookie(void *buf_priv
)
713 struct vb2_dma_sg_buf
*buf
= buf_priv
;
718 const struct vb2_mem_ops vb2_dma_sg_memops
= {
719 .alloc
= vb2_dma_sg_alloc
,
720 .put
= vb2_dma_sg_put
,
721 .get_userptr
= vb2_dma_sg_get_userptr
,
722 .put_userptr
= vb2_dma_sg_put_userptr
,
723 .prepare
= vb2_dma_sg_prepare
,
724 .finish
= vb2_dma_sg_finish
,
725 .vaddr
= vb2_dma_sg_vaddr
,
726 .mmap
= vb2_dma_sg_mmap
,
727 .num_users
= vb2_dma_sg_num_users
,
728 .get_dmabuf
= vb2_dma_sg_get_dmabuf
,
729 .map_dmabuf
= vb2_dma_sg_map_dmabuf
,
730 .unmap_dmabuf
= vb2_dma_sg_unmap_dmabuf
,
731 .attach_dmabuf
= vb2_dma_sg_attach_dmabuf
,
732 .detach_dmabuf
= vb2_dma_sg_detach_dmabuf
,
733 .cookie
= vb2_dma_sg_cookie
,
735 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops
);
737 void *vb2_dma_sg_init_ctx(struct device
*dev
)
739 struct vb2_dma_sg_conf
*conf
;
741 conf
= kzalloc(sizeof(*conf
), GFP_KERNEL
);
743 return ERR_PTR(-ENOMEM
);
749 EXPORT_SYMBOL_GPL(vb2_dma_sg_init_ctx
);
751 void vb2_dma_sg_cleanup_ctx(void *alloc_ctx
)
753 if (!IS_ERR_OR_NULL(alloc_ctx
))
756 EXPORT_SYMBOL_GPL(vb2_dma_sg_cleanup_ctx
);
758 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
759 MODULE_AUTHOR("Andrzej Pietrasiewicz");
760 MODULE_LICENSE("GPL");