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[media] vb2-dma-sg: add support for dmabuf exports

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Add DMABUF export support to vb2-dma-sg.

Signed-off-by: Hans Verkuil <hansverk@cisco.com>
Acked-by: Pawel Osciak <pawel@osciak.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
This commit is contained in:
Hans Verkuil 2014-11-18 09:51:04 -03:00 committed by Mauro Carvalho Chehab
parent e078b79d8a
commit 041c7b6ac7
1 changed files with 170 additions and 0 deletions
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170
drivers/media/v4l2-core/videobuf2-dma-sg.c
View file

@ -407,6 +407,175 @@ static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
return 0;
}
/*********************************************/
/* DMABUF ops for exporters */
/*********************************************/
struct vb2_dma_sg_attachment {
struct sg_table sgt;
enum dma_data_direction dma_dir;
};
static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
struct dma_buf_attachment *dbuf_attach)
{
struct vb2_dma_sg_attachment *attach;
unsigned int i;
struct scatterlist *rd, *wr;
struct sg_table *sgt;
struct vb2_dma_sg_buf *buf = dbuf->priv;
int ret;
attach = kzalloc(sizeof(*attach), GFP_KERNEL);
if (!attach)
return -ENOMEM;
sgt = &attach->sgt;
/* Copy the buf->base_sgt scatter list to the attachment, as we can't
* map the same scatter list to multiple attachments at the same time.
*/
ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL);
if (ret) {
kfree(attach);
return -ENOMEM;
}
rd = buf->dma_sgt->sgl;
wr = sgt->sgl;
for (i = 0; i < sgt->orig_nents; ++i) {
sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
rd = sg_next(rd);
wr = sg_next(wr);
}
attach->dma_dir = DMA_NONE;
dbuf_attach->priv = attach;
return 0;
}
static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf,
struct dma_buf_attachment *db_attach)
{
struct vb2_dma_sg_attachment *attach = db_attach->priv;
struct sg_table *sgt;
if (!attach)
return;
sgt = &attach->sgt;
/* release the scatterlist cache */
if (attach->dma_dir != DMA_NONE)
dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
attach->dma_dir);
sg_free_table(sgt);
kfree(attach);
db_attach->priv = NULL;
}
static struct sg_table *vb2_dma_sg_dmabuf_ops_map(
struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
{
struct vb2_dma_sg_attachment *attach = db_attach->priv;
/* stealing dmabuf mutex to serialize map/unmap operations */
struct mutex *lock = &db_attach->dmabuf->lock;
struct sg_table *sgt;
int ret;
mutex_lock(lock);
sgt = &attach->sgt;
/* return previously mapped sg table */
if (attach->dma_dir == dma_dir) {
mutex_unlock(lock);
return sgt;
}
/* release any previous cache */
if (attach->dma_dir != DMA_NONE) {
dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
attach->dma_dir);
attach->dma_dir = DMA_NONE;
}
/* mapping to the client with new direction */
ret = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, dma_dir);
if (ret <= 0) {
pr_err("failed to map scatterlist\n");
mutex_unlock(lock);
return ERR_PTR(-EIO);
}
attach->dma_dir = dma_dir;
mutex_unlock(lock);
return sgt;
}
static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
struct sg_table *sgt, enum dma_data_direction dma_dir)
{
/* nothing to be done here */
}
static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf)
{
/* drop reference obtained in vb2_dma_sg_get_dmabuf */
vb2_dma_sg_put(dbuf->priv);
}
static void *vb2_dma_sg_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
{
struct vb2_dma_sg_buf *buf = dbuf->priv;
return buf->vaddr ? buf->vaddr + pgnum * PAGE_SIZE : NULL;
}
static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf)
{
struct vb2_dma_sg_buf *buf = dbuf->priv;
return vb2_dma_sg_vaddr(buf);
}
static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf,
struct vm_area_struct *vma)
{
return vb2_dma_sg_mmap(dbuf->priv, vma);
}
static struct dma_buf_ops vb2_dma_sg_dmabuf_ops = {
.attach = vb2_dma_sg_dmabuf_ops_attach,
.detach = vb2_dma_sg_dmabuf_ops_detach,
.map_dma_buf = vb2_dma_sg_dmabuf_ops_map,
.unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap,
.kmap = vb2_dma_sg_dmabuf_ops_kmap,
.kmap_atomic = vb2_dma_sg_dmabuf_ops_kmap,
.vmap = vb2_dma_sg_dmabuf_ops_vmap,
.mmap = vb2_dma_sg_dmabuf_ops_mmap,
.release = vb2_dma_sg_dmabuf_ops_release,
};
static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags)
{
struct vb2_dma_sg_buf *buf = buf_priv;
struct dma_buf *dbuf;
if (WARN_ON(!buf->dma_sgt))
return NULL;
dbuf = dma_buf_export(buf, &vb2_dma_sg_dmabuf_ops, buf->size, flags, NULL);
if (IS_ERR(dbuf))
return NULL;
/* dmabuf keeps reference to vb2 buffer */
atomic_inc(&buf->refcount);
return dbuf;
}
/*********************************************/
/* callbacks for DMABUF buffers */
/*********************************************/
@ -523,6 +692,7 @@ const struct vb2_mem_ops vb2_dma_sg_memops = {
.vaddr = vb2_dma_sg_vaddr,
.mmap = vb2_dma_sg_mmap,
.num_users = vb2_dma_sg_num_users,
.get_dmabuf = vb2_dma_sg_get_dmabuf,
.map_dmabuf = vb2_dma_sg_map_dmabuf,
.unmap_dmabuf = vb2_dma_sg_unmap_dmabuf,
.attach_dmabuf = vb2_dma_sg_attach_dmabuf,