[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.za...@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

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