media: rkisp1: fix grey format iommu page faults

Currently capturing grey format produces page faults
on both selfpath and mainpath. To support greyscale
we can capture YUV422 planar format and configure the U, V
buffers to the dummy buffer.
Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c

@@ -249,7 +249,7 @@ static const struct rkisp1_capture_fmt_cfg rkisp1_sp_fmts[] = {
 		.fourcc = V4L2_PIX_FMT_GREY,
 		.uv_swap = 0,
 		.write_format = RKISP1_MI_CTRL_SP_WRITE_PLA,
-		.output_format = RKISP1_MI_CTRL_SP_OUTPUT_YUV400,
+		.output_format = RKISP1_MI_CTRL_SP_OUTPUT_YUV422,
 		.mbus = MEDIA_BUS_FMT_YUYV8_2X8,
 	},
 	/* rgb */
@@ -631,12 +631,26 @@ static void rkisp1_set_next_buf(struct rkisp1_capture *cap)
 		rkisp1_write(cap->rkisp1,
 			     buff_addr[RKISP1_PLANE_Y],
 			     cap->config->mi.y_base_ad_init);
+		/*
+		 * In order to support grey format we capture
+		 * YUV422 planar format from the camera and
+		 * set the U and V planes to the dummy buffer
+		 */
+		if (cap->pix.cfg->fourcc == V4L2_PIX_FMT_GREY) {
+			rkisp1_write(cap->rkisp1,
+				     cap->buf.dummy.dma_addr,
+				     cap->config->mi.cb_base_ad_init);
+			rkisp1_write(cap->rkisp1,
+				     cap->buf.dummy.dma_addr,
+				     cap->config->mi.cr_base_ad_init);
+		} else {
 			rkisp1_write(cap->rkisp1,
 				     buff_addr[RKISP1_PLANE_CB],
 				     cap->config->mi.cb_base_ad_init);
 			rkisp1_write(cap->rkisp1,
 				     buff_addr[RKISP1_PLANE_CR],
 				     cap->config->mi.cr_base_ad_init);
+		}
 	} else {
 		/*
 		 * Use the dummy space allocated by dma_alloc_coherent to