media: rcar-csi2: Optimize rcsi2_calc_mbps()

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>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/media/platform/renesas/rcar-csi2.c b/drivers/media/platform/renesas/rcar-csi2.c
index a2a87c5bfd7c51ad9edf80437f4e4694d7121e11..7305cc4a04cb12db1f98ac9857096b8aee0553f0 100644 (file)
--- a/drivers/media/platform/renesas/rcar-csi2.c
+++ b/drivers/media/platform/renesas/rcar-csi2.c
@@ -1006,15 +1006,10 @@ 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;
@@ -1022,28 +1017,41 @@ 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;
+               const 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);