[PATCH] [media] videobuf2-dma-contig: allow to vmap contiguous dma buffers

[PATCH] [media] videobuf2-dma-contig: allow to vmap contiguous dma buffers

[Philipp Zabel]

This allows drivers to vmap contiguous dma buffers so they can inspect the
buffer contents with the CPU. This will be needed for the CODA driver's JPEG
handling. On CODA960, the header parsing has to be done on the CPU. The
hardware modules can only process the entropy coded segment after all
registers and tables are set up.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
---
 drivers/media/v4l2-core/videobuf2-dma-contig.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index 880be07..6b254b8 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -98,6 +98,9 @@ static void *vb2_dc_vaddr(void *buf_priv)
 {
 	struct vb2_dc_buf *buf = buf_priv;
 
+	if (!buf->vaddr && buf->db_attach)
+		buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf);
+
 	return buf->vaddr;
 }
 
@@ -735,6 +738,7 @@ static int vb2_dc_map_dmabuf(void *mem_priv)
 
 	buf->dma_addr = sg_dma_address(sgt->sgl);
 	buf->dma_sgt = sgt;
+	buf->vaddr = NULL;
 
 	return 0;
 }
@@ -754,6 +758,10 @@ static void vb2_dc_unmap_dmabuf(void *mem_priv)
 		return;
 	}
 
+	if (buf->vaddr) {
+		dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr);
+		buf->vaddr = NULL;
+	}
 	dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
 
 	buf->dma_addr = 0;
-- 
2.0.0.rc2

Re: [PATCH] [media] videobuf2-dma-contig: allow to vmap contiguous dma buffers

[Marek Szyprowski]

Hello,

On 2014-05-26 16:17, Philipp Zabel wrote:
> This allows drivers to vmap contiguous dma buffers so they can inspect the
> buffer contents with the CPU. This will be needed for the CODA driver's JPEG
> handling. On CODA960, the header parsing has to be done on the CPU. The
> hardware modules can only process the entropy coded segment after all
> registers and tables are set up.
>
> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>

> ---
>   drivers/media/v4l2-core/videobuf2-dma-contig.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
>
> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> index 880be07..6b254b8 100644
> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> @@ -98,6 +98,9 @@ static void *vb2_dc_vaddr(void *buf_priv)
>   {
>   	struct vb2_dc_buf *buf = buf_priv;
>   
> +	if (!buf->vaddr && buf->db_attach)
> +		buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf);
> +
>   	return buf->vaddr;
>   }
>   
> @@ -735,6 +738,7 @@ static int vb2_dc_map_dmabuf(void *mem_priv)
>   
>   	buf->dma_addr = sg_dma_address(sgt->sgl);
>   	buf->dma_sgt = sgt;
> +	buf->vaddr = NULL;
>   
>   	return 0;
>   }
> @@ -754,6 +758,10 @@ static void vb2_dc_unmap_dmabuf(void *mem_priv)
>   		return;
>   	}
>   
> +	if (buf->vaddr) {
> +		dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr);
> +		buf->vaddr = NULL;
> +	}
>   	dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
>   
>   	buf->dma_addr = 0;

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland