When support for V4L2_FLAG_MEMORY_NON_CONSISTENT was removed in
commit 129134e5415d ("media: media/v4l2: remove
V4L2_FLAG_MEMORY_NON_CONSISTENT flag"),
vb2_dc_dmabuf_ops_{begin,end}_cpu_access() functions were made
no-ops. Later, when support for V4L2_MEMORY_FLAG_NON_COHERENT was
introduced in commit c0acf9cfeee0 ("media: videobuf2: handle
V4L2_MEMORY_FLAG_NON_COHERENT flag"), the above functions remained
no-ops, making cache maintenance for non-coherent dmabufs allocated by
dma-contig impossible.

Fix this by reintroducing dma_sync_sgtable_for_{cpu,device} and
{flush,invalidate}_kernel_vmap_range calls to
vb2_dc_dmabuf_ops_{begin,end}_cpu_access() functions for non-coherent
buffers.

Fixes: c0acf9cfeee0 ("media: videobuf2: handle V4L2_MEMORY_FLAG_NON_COHERENT flag")
Cc: stable@vger.kernel.org
Signed-off-by: Mikhail Rudenko <mike.rudenko@gmail.com>
---
 .../media/common/videobuf2/videobuf2-dma-contig.c  | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index bb0b7fa67b539aa73ad5ccf3c3bc318e26f8a4cb..146d7997a0da5989fb081a6f28ce0641fe726e63 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c

@@ -427,6 +427,17 @@ static int
 vb2_dc_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf,
                                   enum dma_data_direction direction)
 {
+       struct vb2_dc_buf *buf = dbuf->priv;
+       struct sg_table *sgt = buf->dma_sgt;
+
+       if (!buf->non_coherent_mem)
+               return 0;
+
+       if (buf->vaddr)
+               invalidate_kernel_vmap_range(buf->vaddr, buf->size);
+
+       dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
+
        return 0;
 }

@@ -434,6 +445,17 @@ static int
 vb2_dc_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf,
                                 enum dma_data_direction direction)
 {
+       struct vb2_dc_buf *buf = dbuf->priv;
+       struct sg_table *sgt = buf->dma_sgt;
+
+       if (!buf->non_coherent_mem)
+               return 0;
+
+       if (buf->vaddr)
+               flush_kernel_vmap_range(buf->vaddr, buf->size);
+
+       dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
+
        return 0;
 }