[PATCH v3 07/15] media: rcar-csi2: Optimize rcsi2_calc_mbps()

[Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>]

With modern drivers supporting link-freq, we don't need to do any
calculations based on the bpp and number of lanes when figuring out the
link frequency. However, the code currently always runs code to get the
bpp and number of lanes.

Optimize the rcsi2_calc_mbps() so that we only do that when needed, i.e.
when querying the link-freq is not supported by the upstream subdevice.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
---
 drivers/media/platform/renesas/rcar-csi2.c | 50 +++++++++++++++++-------------
 1 file changed, 29 insertions(+), 21 deletions(-)

diff --git a/drivers/media/platform/renesas/rcar-csi2.c b/drivers/media/platform/renesas/rcar-csi2.c
index 90973f3cba38..e0a0fd96459b 100644
--- a/drivers/media/platform/renesas/rcar-csi2.c
+++ b/drivers/media/platform/renesas/rcar-csi2.c
@@ -1001,15 +1001,10 @@ static int rcsi2_get_active_lanes(struct rcar_csi2 *priv,
 static int rcsi2_calc_mbps(struct rcar_csi2 *priv,
 			   struct v4l2_subdev_state *state)
 {
-	const struct rcar_csi2_format *format;
-	struct v4l2_mbus_framefmt *fmt;
 	struct media_pad *remote_pad;
 	struct v4l2_subdev *source;
-	unsigned int lanes;
-	unsigned int bpp;
 	s64 freq;
 	u64 mbps;
-	int ret;
 
 	if (!priv->remote)
 		return -ENODEV;
@@ -1017,28 +1012,41 @@ static int rcsi2_calc_mbps(struct rcar_csi2 *priv,
 	source = priv->remote;
 	remote_pad = &source->entity.pads[priv->remote_pad];
 
-	ret = rcsi2_get_active_lanes(priv, &lanes);
-	if (ret)
-		return ret;
+	/*
+	 * First try to get the real link freq. If that fails, try the heuristic
+	 * method with bpp and lanes (but that only works for one route).
+	 */
+	freq = v4l2_get_link_freq(remote_pad, 0, 0);
+	if (freq < 0) {
+		const struct rcar_csi2_format *format;
+		struct v4l2_mbus_framefmt *fmt;
+		unsigned int lanes;
+		unsigned int bpp;
+		int ret;
 
-	fmt = v4l2_subdev_state_get_format(state, RCAR_CSI2_SINK);
-	if (!fmt)
-		return -EINVAL;
+		ret = rcsi2_get_active_lanes(priv, &lanes);
+		if (ret)
+			return ret;
 
-	format = rcsi2_code_to_fmt(fmt->code);
-	if (!format)
-		return -EINVAL;
+		fmt = v4l2_subdev_state_get_format(state, RCAR_CSI2_SINK);
+		if (!fmt)
+			return -EINVAL;
 
-	bpp = format->bpp;
+		format = rcsi2_code_to_fmt(fmt->code);
+		if (!format)
+			return -EINVAL;
 
-	freq = v4l2_get_link_freq(remote_pad, bpp, 2 * lanes);
-	if (freq < 0) {
-		int ret = (int)freq;
+		bpp = format->bpp;
 
-		dev_err(priv->dev, "failed to get link freq for %s: %d\n",
-			source->name, ret);
+		freq = v4l2_get_link_freq(remote_pad, bpp, 2 * lanes);
+		if (freq < 0) {
+			int ret = (int)freq;
 
-		return ret;
+			dev_err(priv->dev, "failed to get link freq for %s: %d\n",
+				source->name, ret);
+
+			return ret;
+		}
 	}
 
 	mbps = div_u64(freq * 2, MEGA);

-- 
2.43.0