Hi Jacopo,
On 2020-07-15 09:13:25 +0200, Jacopo Mondi wrote:
> 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.
I see your point but please initialize it to UINT_MAX instead of -1U
then :-)
>
> 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
--
Regards,
Niklas Söderlund
