[media] s5p-mfc: Set DMA_ATTR_ALLOC_SINGLE_PAGES

We do video allocation all the time and we need it to be fast.  Plus TLB
efficiency isn't terribly important for video.

That means we want to set DMA_ATTR_ALLOC_SINGLE_PAGES.

See also the previous change (commit 14d3ae2e "ARM: dma-mapping: Use
DMA_ATTR_ALLOC_SINGLE_PAGES hint to optimize allocation").

[m.szyprowski: rebased patch onto v4.9-rc1 and adapted changes
 to latest videbuf2 changes, this simplifies code changes to
 only set proper dma attribute flag and comment the reason
 for it, added commit id of arch/arm/mm patch]
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/s5p-mfc/s5p_mfc.c

@@ -851,6 +851,11 @@ static int s5p_mfc_open(struct file *file)
 		ret = -ENOENT;
 		goto err_queue_init;
 	}
+	/*
+	 * We'll do mostly sequential access, so sacrifice TLB efficiency for
+	 * faster allocation.
+	 */
+	q->dma_attrs = DMA_ATTR_ALLOC_SINGLE_PAGES;
 	q->mem_ops = &vb2_dma_contig_memops;
 	q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
 	ret = vb2_queue_init(q);
@@ -881,6 +886,12 @@ static int s5p_mfc_open(struct file *file)
 	 * will keep the value of bytesused intact.
 	 */
 	q->allow_zero_bytesused = 1;
+
+	/*
+	 * We'll do mostly sequential access, so sacrifice TLB efficiency for
+	 * faster allocation.
+	 */
+	q->dma_attrs = DMA_ATTR_ALLOC_SINGLE_PAGES;
 	q->mem_ops = &vb2_dma_contig_memops;
 	q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
 	ret = vb2_queue_init(q);