Hi Niklas,
On Wed, Jul 15, 2020 at 08:55:38AM +0200, Niklas Söderlund wrote:
> Hi Jacopo,
>
> Thanks for your work.
>
> On 2020-07-14 15:58:12 +0200, Jacopo Mondi wrote:
> > Use the newly introduced get_mbus_config() subdevice pad operation to
> > retrieve the remote subdevice MIPI CSI-2 bus configuration and configure
> > the number of active data lanes accordingly.
> >
> > In order to be able to call the remote subdevice operation cache the
> > index of the remote pad connected to the single CSI-2 input port.
> >
> > Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
> > ---
> > drivers/media/platform/rcar-vin/rcar-csi2.c | 74 +++++++++++++++++++--
> > 1 file changed, 67 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c b/drivers/media/platform/rcar-vin/rcar-csi2.c
> > index c6cc4f473a07..d39f312ebff9 100644
> > --- a/drivers/media/platform/rcar-vin/rcar-csi2.c
> > +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
> > @@ -364,6 +364,7 @@ struct rcar_csi2 {
> > struct v4l2_async_notifier notifier;
> > struct v4l2_async_subdev asd;
> > struct v4l2_subdev *remote;
> > + unsigned int remote_pad;
> >
> > struct v4l2_mbus_framefmt mf;
> >
> > @@ -409,13 +410,14 @@ static void rcsi2_exit_standby(struct rcar_csi2 *priv)
> > reset_control_deassert(priv->rstc);
> > }
> >
> > -static int rcsi2_wait_phy_start(struct rcar_csi2 *priv)
> > +static int rcsi2_wait_phy_start(struct rcar_csi2 *priv,
> > + unsigned int active_lanes)
>
> Maybe s/active_lanes/lanes/ here and below?
>
ok, I guess it's not important to convey the distinction between
active and available lanes here.
> > {
> > unsigned int timeout;
> >
> > /* Wait for the clock and data lanes to enter LP-11 state. */
> > for (timeout = 0; timeout <= 20; timeout++) {
> > - const u32 lane_mask = (1 << priv->lanes) - 1;
> > + const u32 lane_mask = (1 << active_lanes) - 1;
> >
> > if ((rcsi2_read(priv, PHCLM_REG) & PHCLM_STOPSTATECKL) &&
> > (rcsi2_read(priv, PHDLM_REG) & lane_mask) == lane_mask)
> > @@ -447,7 +449,8 @@ static int rcsi2_set_phypll(struct rcar_csi2 *priv, unsigned int mbps)
> > return 0;
> > }
> >
> > -static int rcsi2_calc_mbps(struct rcar_csi2 *priv, unsigned int bpp)
> > +static int rcsi2_calc_mbps(struct rcar_csi2 *priv, unsigned int bpp,
> > + unsigned int active_lanes)
> > {
> > struct v4l2_subdev *source;
> > struct v4l2_ctrl *ctrl;
> > @@ -472,15 +475,63 @@ static int rcsi2_calc_mbps(struct rcar_csi2 *priv, unsigned int bpp)
> > * bps = link_freq * 2
> > */
> > mbps = v4l2_ctrl_g_ctrl_int64(ctrl) * bpp;
> > - do_div(mbps, priv->lanes * 1000000);
> > + do_div(mbps, active_lanes * 1000000);
> >
> > return mbps;
> > }
> >
> > +static int rcsi2_config_active_lanes(struct rcar_csi2 *priv,
> > + unsigned int *active_lanes)
>
> I would name this rcsi2_get_active_lanes() as it does not configure
> anything just queries the subdevice for information.
>
ack
> > +{
> > + struct v4l2_mbus_config mbus_config = { 0 };
> > + unsigned int num_lanes = (-1U);
>
> This looks odd and could just be set 0 with the same effect but clearer
> to read.
>
Not really.
Have a look at this part:
if (mbus_config.flags & V4L2_MBUS_CSI2_1_LANE)
num_lanes = 1;
else if (mbus_config.flags & V4L2_MBUS_CSI2_2_LANE)
num_lanes = 2;
else if (mbus_config.flags & V4L2_MBUS_CSI2_3_LANE)
num_lanes = 3;
else if (mbus_config.flags & V4L2_MBUS_CSI2_4_LANE)
num_lanes = 4;
if (num_lanes > priv->lanes) {
^^ I should then change this one to:
if (!num_lanes)
But this does not protect against the case num_lanes is actually set
to a meaningful value, but it's larger than the number of actually
available lanes (which is held by priv->lanes).
I would keep this one as it is.
Thanks
j
> > + int ret;
> > +
> > + *active_lanes = priv->lanes;
> > + ret = v4l2_subdev_call(priv->remote, pad, get_mbus_config,
> > + priv->remote_pad, &mbus_config);
> > + if (ret == -ENOIOCTLCMD) {
> > + dev_dbg(priv->dev, "No remote mbus configuration available\n");
> > + return 0;
> > + }
> > +
> > + if (ret) {
> > + dev_err(priv->dev, "Failed to get remote mbus configuration\n");
> > + return ret;
> > + }
> > +
> > + if (mbus_config.type != V4L2_MBUS_CSI2_DPHY) {
> > + dev_err(priv->dev, "Unsupported media bus type %u\n",
> > + mbus_config.type);
> > + return -EINVAL;
> > + }
> > +
> > + if (mbus_config.flags & V4L2_MBUS_CSI2_1_LANE)
> > + num_lanes = 1;
> > + else if (mbus_config.flags & V4L2_MBUS_CSI2_2_LANE)
> > + num_lanes = 2;
> > + else if (mbus_config.flags & V4L2_MBUS_CSI2_3_LANE)
> > + num_lanes = 3;
> > + else if (mbus_config.flags & V4L2_MBUS_CSI2_4_LANE)
> > + num_lanes = 4;
> > +
> > + if (num_lanes > priv->lanes) {
> > + dev_err(priv->dev,
> > + "Unsupported mbus config: too many data lanes %u\n",
> > + num_lanes);
> > + return -EINVAL;
> > + }
> > +
> > + *active_lanes = num_lanes;
> > +
> > + return 0;
> > +}
> > +
> > static int rcsi2_start_receiver(struct rcar_csi2 *priv)
> > {
> > const struct rcar_csi2_format *format;
> > u32 phycnt, vcdt = 0, vcdt2 = 0, fld = 0;
> > + unsigned int active_lanes;
> > unsigned int i;
> > int mbps, ret;
> >
> > @@ -522,10 +573,18 @@ static int rcsi2_start_receiver(struct rcar_csi2 *priv)
> > fld |= FLD_FLD_NUM(1);
> > }
> >
> > + /*
> > + * Get the number of active data lanes inspecting the remote mbus
> > + * configuration.
> > + */
> > + ret = rcsi2_config_active_lanes(priv, &active_lanes);
> > + if (ret)
> > + return ret;
> > +
> > phycnt = PHYCNT_ENABLECLK;
> > - phycnt |= (1 << priv->lanes) - 1;
> > + phycnt |= (1 << active_lanes) - 1;
> >
> > - mbps = rcsi2_calc_mbps(priv, format->bpp);
> > + mbps = rcsi2_calc_mbps(priv, format->bpp, active_lanes);
> > if (mbps < 0)
> > return mbps;
> >
> > @@ -572,7 +631,7 @@ static int rcsi2_start_receiver(struct rcar_csi2 *priv)
> > rcsi2_write(priv, PHYCNT_REG, phycnt | PHYCNT_SHUTDOWNZ);
> > rcsi2_write(priv, PHYCNT_REG, phycnt | PHYCNT_SHUTDOWNZ | PHYCNT_RSTZ);
> >
> > - ret = rcsi2_wait_phy_start(priv);
> > + ret = rcsi2_wait_phy_start(priv, active_lanes);
> > if (ret)
> > return ret;
> >
> > @@ -749,6 +808,7 @@ static int rcsi2_notify_bound(struct v4l2_async_notifier *notifier,
> > }
> >
> > priv->remote = subdev;
> > + priv->remote_pad = pad;
> >
> > dev_dbg(priv->dev, "Bound %s pad: %d\n", subdev->name, pad);
> >
> > --
> > 2.27.0
> >
>
> --
> Regards,
> Niklas Söderlund
