media: rp1: csi2: Use get_frame_desc to get CSI-2 VC and DT

Use get_frame_desc pad op for asking the CSI-2 VC and DT from the source
device driver, instead of hardcoding to VC 0, and getting the DT from a
formats table. To keep backward compatibility with sources that do not
implement get_frame_desc, implement a fallback mechanism that always
uses VC 0, and gets the DT from the formats table, based on the CSI2's
sink pad's format.

Signed-off-by: Tomi Valkeinen <[email protected]>

Author: tomba

drivers/media/platform/raspberrypi/rp1_cfe/cfe.c

@@ -838,7 +838,7 @@ static void cfe_start_channel(struct cfe_node *node)
 		 * this is handled by the CSI2 AUTO_ARM mode.
 		 */
 		csi2_start_channel(&cfe->csi2, cfe->fe_csi2_channel,
-				   fmt->csi_dt, CSI2_MODE_FE_STREAMING,
+				   CSI2_MODE_FE_STREAMING,
 				   true, false, width, height);
 		csi2_set_buffer(&cfe->csi2, cfe->fe_csi2_channel, 0, 0, -1);
 		pisp_fe_start(&cfe->fe);
@@ -872,7 +872,7 @@ static void cfe_start_channel(struct cfe_node *node)
 			}
 		}
 		/* Unconditionally start this CSI2 channel. */
-		csi2_start_channel(&cfe->csi2, node->id, fmt->csi_dt,
+		csi2_start_channel(&cfe->csi2, node->id,
 				   mode,
 				   /* Auto arm */
 				   false,

drivers/media/platform/raspberrypi/rp1_cfe/csi2.c

@@ -324,12 +324,84 @@ void csi2_set_compression(struct csi2_device *csi2, unsigned int channel,
 	csi2_reg_write(csi2, CSI2_CH_COMP_CTRL(channel), compression);
 }
 
+static int csi2_get_vc_dt_fallback(struct csi2_device *csi2,
+				   unsigned int channel, u8 *vc, u8 *dt)
+{
+	struct v4l2_subdev *sd = &csi2->sd;
+	struct v4l2_subdev_state *state;
+	struct v4l2_mbus_framefmt *fmt;
+	const struct cfe_fmt *cfe_fmt;
+
+	state = v4l2_subdev_get_locked_active_state(sd);
+
+	/* Without Streams API, the channel number matches the sink pad */
+	fmt = v4l2_subdev_get_pad_format(sd, state, channel);
+	if (!fmt)
+		return -EINVAL;
+
+	cfe_fmt = find_format_by_code(fmt->code);
+	if (!cfe_fmt)
+		return -EINVAL;
+
+	*vc = 0;
+	*dt = cfe_fmt->csi_dt;
+
+	return 0;
+}
+
+static int csi2_get_vc_dt(struct csi2_device *csi2, unsigned int channel,
+			  u8 *vc, u8 *dt)
+{
+	struct v4l2_mbus_frame_desc remote_desc;
+	const struct media_pad *remote_pad;
+	struct v4l2_subdev *source_sd;
+	int ret;
+
+	/* Without Streams API, the channel number matches the sink pad */
+	remote_pad = media_pad_remote_pad_first(&csi2->pad[channel]);
+	if (!remote_pad)
+		return -EPIPE;
+
+	source_sd = media_entity_to_v4l2_subdev(remote_pad->entity);
+
+	ret = v4l2_subdev_call(source_sd, pad, get_frame_desc,
+			       remote_pad->index, &remote_desc);
+	if (ret == -ENOIOCTLCMD) {
+		csi2_dbg("source does not support get_frame_desc, use fallback\n");
+		return csi2_get_vc_dt_fallback(csi2, channel, vc, dt);
+	} else if (ret) {
+		csi2_err("Failed to get frame descriptor\n");
+		return ret;
+	}
+
+	if (remote_desc.type != V4L2_MBUS_FRAME_DESC_TYPE_CSI2) {
+		csi2_err("Frame descriptor does not describe CSI-2 link");
+		return -EINVAL;
+	}
+
+	if (remote_desc.num_entries != 1) {
+		csi2_err("Frame descriptor does not have a single entry");
+		return -EINVAL;
+	}
+
+	*vc = remote_desc.entry[0].bus.csi2.vc;
+	*dt = remote_desc.entry[0].bus.csi2.dt;
+
+	return 0;
+}
+
 void csi2_start_channel(struct csi2_device *csi2, unsigned int channel,
-			u16 dt, enum csi2_mode mode, bool auto_arm,
+			enum csi2_mode mode, bool auto_arm,
 			bool pack_bytes, unsigned int width,
 			unsigned int height)
 {
 	u32 ctrl;
+	int ret;
+	u8 vc, dt;
+
+	ret = csi2_get_vc_dt(csi2, channel, &vc, &dt);
+	if (ret)
+		return;
 
 	csi2_dbg("%s [%u]\n", __func__, channel);
 
@@ -369,6 +441,7 @@ void csi2_start_channel(struct csi2_device *csi2, unsigned int channel,
 		csi2_reg_write(csi2, CSI2_CH_FRAME_SIZE(channel), 0);
 	}
 
+	set_field(&ctrl, vc, VC_MASK);
 	set_field(&ctrl, dt, DT_MASK);
 	csi2_reg_write(csi2, CSI2_CH_CTRL(channel), ctrl);
 	csi2->num_lines[channel] = height;

drivers/media/platform/raspberrypi/rp1_cfe/csi2.h

@@ -79,7 +79,7 @@ void csi2_set_compression(struct csi2_device *csi2, unsigned int channel,
 			  enum csi2_compression_mode mode, unsigned int shift,
 			  unsigned int offset);
 void csi2_start_channel(struct csi2_device *csi2, unsigned int channel,
-			u16 dt, enum csi2_mode mode, bool auto_arm,
+			enum csi2_mode mode, bool auto_arm,
 			bool pack_bytes, unsigned int width,
 			unsigned int height);
 void csi2_stop_channel(struct csi2_device *csi2, unsigned int channel);