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[media] v4l: vb2-dma-contig: add support for DMABUF exporting 

This patch adds support for exporting a dma-contig buffer using
DMABUF interface.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Tested-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Tomasz Stanislawski 2012-06-14 11:32:25 -03:00 committed by Mauro Carvalho Chehab
parent 83ae7c5a1b
commit 9ef2cbeb81
1 changed files with 200 additions and 0 deletions
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200
drivers/media/v4l2-core/videobuf2-dma-contig.c
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@ -36,6 +36,7 @@ struct vb2_dc_buf {
/* MMAP related */
struct vb2_vmarea_handler handler;
atomic_t refcount;
struct sg_table *sgt_base;
/* USERPTR related */
struct vm_area_struct *vma;
@ -142,6 +143,10 @@ static void vb2_dc_put(void *buf_priv)
if (!atomic_dec_and_test(&buf->refcount))
return;
if (buf->sgt_base) {
sg_free_table(buf->sgt_base);
kfree(buf->sgt_base);
}
dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
kfree(buf);
}
@ -212,6 +217,200 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
return 0;
}
/*********************************************/
/* DMABUF ops for exporters */
/*********************************************/
struct vb2_dc_attachment {
struct sg_table sgt;
enum dma_data_direction dir;
};
static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
struct dma_buf_attachment *dbuf_attach)
{
struct vb2_dc_attachment *attach;
unsigned int i;
struct scatterlist *rd, *wr;
struct sg_table *sgt;
struct vb2_dc_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->sgt_base->orig_nents, GFP_KERNEL);
if (ret) {
kfree(attach);
return -ENOMEM;
}
rd = buf->sgt_base->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->dir = DMA_NONE;
dbuf_attach->priv = attach;
return 0;
}
static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf,
struct dma_buf_attachment *db_attach)
{
struct vb2_dc_attachment *attach = db_attach->priv;
struct sg_table *sgt;
if (!attach)
return;
sgt = &attach->sgt;
/* release the scatterlist cache */
if (attach->dir != DMA_NONE)
dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
attach->dir);
sg_free_table(sgt);
kfree(attach);
db_attach->priv = NULL;
}
static struct sg_table *vb2_dc_dmabuf_ops_map(
struct dma_buf_attachment *db_attach, enum dma_data_direction dir)
{
struct vb2_dc_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->dir == dir) {
mutex_unlock(lock);
return sgt;
}
/* release any previous cache */
if (attach->dir != DMA_NONE) {
dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
attach->dir);
attach->dir = DMA_NONE;
}
/* mapping to the client with new direction */
ret = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, dir);
if (ret <= 0) {
pr_err("failed to map scatterlist\n");
mutex_unlock(lock);
return ERR_PTR(-EIO);
}
attach->dir = dir;
mutex_unlock(lock);
return sgt;
}
static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
struct sg_table *sgt, enum dma_data_direction dir)
{
/* nothing to be done here */
}
static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf)
{
/* drop reference obtained in vb2_dc_get_dmabuf */
vb2_dc_put(dbuf->priv);
}
static void *vb2_dc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
{
struct vb2_dc_buf *buf = dbuf->priv;
return buf->vaddr + pgnum * PAGE_SIZE;
}
static void *vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf)
{
struct vb2_dc_buf *buf = dbuf->priv;
return buf->vaddr;
}
static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf,
struct vm_area_struct *vma)
{
return vb2_dc_mmap(dbuf->priv, vma);
}
static struct dma_buf_ops vb2_dc_dmabuf_ops = {
.attach = vb2_dc_dmabuf_ops_attach,
.detach = vb2_dc_dmabuf_ops_detach,
.map_dma_buf = vb2_dc_dmabuf_ops_map,
.unmap_dma_buf = vb2_dc_dmabuf_ops_unmap,
.kmap = vb2_dc_dmabuf_ops_kmap,
.kmap_atomic = vb2_dc_dmabuf_ops_kmap,
.vmap = vb2_dc_dmabuf_ops_vmap,
.mmap = vb2_dc_dmabuf_ops_mmap,
.release = vb2_dc_dmabuf_ops_release,
};
static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
{
int ret;
struct sg_table *sgt;
sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
if (!sgt) {
dev_err(buf->dev, "failed to alloc sg table\n");
return NULL;
}
ret = dma_get_sgtable(buf->dev, sgt, buf->vaddr, buf->dma_addr,
buf->size);
if (ret < 0) {
dev_err(buf->dev, "failed to get scatterlist from DMA API\n");
kfree(sgt);
return NULL;
}
return sgt;
}
static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv)
{
struct vb2_dc_buf *buf = buf_priv;
struct dma_buf *dbuf;
if (!buf->sgt_base)
buf->sgt_base = vb2_dc_get_base_sgt(buf);
if (WARN_ON(!buf->sgt_base))
return NULL;
dbuf = dma_buf_export(buf, &vb2_dc_dmabuf_ops, buf->size, 0);
if (IS_ERR(dbuf))
return NULL;
/* dmabuf keeps reference to vb2 buffer */
atomic_inc(&buf->refcount);
return dbuf;
}
/*********************************************/
/* callbacks for USERPTR buffers */
/*********************************************/
@ -519,6 +718,7 @@ static void *vb2_dc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
const struct vb2_mem_ops vb2_dma_contig_memops = {
.alloc = vb2_dc_alloc,
.put = vb2_dc_put,
.get_dmabuf = vb2_dc_get_dmabuf,
.cookie = vb2_dc_cookie,
.vaddr = vb2_dc_vaddr,
.mmap = vb2_dc_mmap,