[Patch v2 26/35] media: ti-vpe: vpdma: Use bidirectional cached buffers

From: Benoit Parrot
Date: Fri Nov 18 2016 - 18:24:53 EST

From: Nikhil Devshatwar <nikhil.nd@xxxxxx>

VPDMA buffer will be used by CPU as well as by the VPDMA.
CPU will write/update the VPDMA descriptors containing data
about the video buffer DMA addresses.
VPDMA will write the "write descriptor" containing the
data about the DMA operation.

When mapping/unmapping the buffer, driver has to take care of
WriteBack and invalidation of the cache so that all the
coherency is maintained from both directions.

Use DMA_BIDIRECTIONAL to maintain coherency between CPU and VPDMA.

Signed-off-by: Nikhil Devshatwar <nikhil.nd@xxxxxx>
Signed-off-by: Benoit Parrot <bparrot@xxxxxx>
Acked-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
drivers/media/platform/ti-vpe/vpdma.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/ti-vpe/vpdma.c b/drivers/media/platform/ti-vpe/vpdma.c
index 070937fe1af6..2d13644a28a8 100644
--- a/drivers/media/platform/ti-vpe/vpdma.c
+++ b/drivers/media/platform/ti-vpe/vpdma.c
@@ -367,7 +367,7 @@ int vpdma_map_desc_buf(struct vpdma_data *vpdma, struct vpdma_buf *buf)

buf->dma_addr = dma_map_single(dev, buf->addr, buf->size,
if (dma_mapping_error(dev, buf->dma_addr)) {
dev_err(dev, "failed to map buffer\n");
return -EINVAL;
@@ -388,7 +388,8 @@ void vpdma_unmap_desc_buf(struct vpdma_data *vpdma, struct vpdma_buf *buf)
struct device *dev = &vpdma->pdev->dev;

if (buf->mapped)
- dma_unmap_single(dev, buf->dma_addr, buf->size, DMA_TO_DEVICE);
+ dma_unmap_single(dev, buf->dma_addr, buf->size,

buf->mapped = false;