Hi Tomasz,
On Wednesday 10 October 2012 16:46:39 Tomasz Stanislawski wrote:
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
Acked-by: Laurent Pinchart laurent.pinchart@ideasonboard.com
drivers/media/v4l2-core/videobuf2-dma-contig.c | 200 +++++++++++++++++++++ 1 file changed, 200 insertions(+)
diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 0e065ce..b138b5c 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c @@ -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);
} @@ -213,6 +218,200 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma) }
/*********************************************/ +/* 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,