Hi Jacopo,
Thinking even more about this.
On Sat, Jan 22, 2022 at 03:23:19AM +0200, Laurent Pinchart wrote:
> On Sat, Jan 22, 2022 at 03:14:33AM +0200, Laurent Pinchart wrote:
> > On Sun, Oct 17, 2021 at 08:24:40PM +0200, Jacopo Mondi wrote:
> > > Use the routing table to configure the link output order and link
> > > masking.
> > >
> > > The link output order defines the CSI-2 virtual channel a GSML stream
> >
> > s/GSML/GMSL/
> >
> > > is output on. Configure ordering at stream start time and at chip
> > > setup time. This last step requires to move the chip initialization
> > > function after the V4L2 setup phase as it requires the subdev state from
> > > where the routing table is retrieved from to be initialized.
> > >
> > > Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
> > > ---
> > > drivers/media/i2c/max9286.c | 103 ++++++++++++++++++++++--------------
> > > 1 file changed, 64 insertions(+), 39 deletions(-)
> > >
> > > diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
> > > index 2e635179aec0..3485478f08a5 100644
> > > --- a/drivers/media/i2c/max9286.c
> > > +++ b/drivers/media/i2c/max9286.c
> > > @@ -500,6 +500,61 @@ static int max9286_check_config_link(struct max9286_priv *priv,
> > > return 0;
> > > }
> > >
> > > +/*
> > > + * Configure the links output order (which defines on which CSI-2 VC a
> > > + * link is output on) and configure link masking.
> > > + */
> > > +static void max9286_config_links(struct max9286_priv *priv)
> > > +{
> > > + const struct v4l2_subdev_krouting *routing;
> > > + struct v4l2_subdev_state *state;
> > > + u8 link_order = 0;
> > > + u8 vc_mask = 0xf;
> > > + unsigned int i;
> > > +
> > > + state = v4l2_subdev_lock_active_state(&priv->sd);
> > > + routing = &state->routing;
> > > +
> > > + for (i = 0; i < routing->num_routes; ++i) {
> > > + struct v4l2_subdev_route *route = &routing->routes[i];
>
> And I think we should also ignore disabled routes, so using
>
> for_each_active_route(&state->routing, route) {
>
> is likely better too.
>
> > > +
> > > + if (!(priv->route_mask & BIT(i)))
> >
> > Shouldn't this be BIT(route->sink_pad), has route_mask stores a bitmask
> > of sink pads (see max9286_set_routing()) ?
> >
> > > + continue;
> > > +
> > > + /* Assign the CSI-2 VC using the source stream number. */
Is this even correct ? The source stream number is arbitrary selected by
userspace, and the MAX9286 requires (at least according to the comment
in max9286_setup()) to assign orders sequentially from 0 without any
hole. This code doesn't seem to guarantee that. Should we instead move
the link_order table to this function and index it with priv->route_mask
?
> > > + link_order |= route->source_stream << (2 * route->sink_pad);
> > > + vc_mask &= ~BIT(route->source_stream);
> > > + }
> > > +
> > > + /*
> > > + * This might look rather silly, but now that we have assigned a
> > > + * VC to the enabled routes, we have to assign one to the disabled
> > > + * routes as well, as there cannot be two sources with the same VC.
> > > + */
> > > + for (i = 0; i < MAX9286_NUM_GMSL; ++i) {
> > > + unsigned int vc;
> > > +
> > > + if (priv->route_mask & BIT(i))
> > > + continue;
> > > +
> > > + /* ffs() counts from 1. */
> > > + vc = ffs(vc_mask) - 1;
> > > + link_order |= vc << (2 * i);
> > > + vc_mask &= ~BIT(vc);
> > > + }
This can then be dropped.
The max9286_get_frame_desc() function will need to be updated
accordingly.
> > > +
> > > + /*
> > > + * Use the enabled routes to enable GMSL links, configure the CSI-2
> > > + * output order, mask unused links and autodetect link used as CSI
> > > + * clock source.
> > > + */
> > > + max9286_write(priv, 0x00, MAX9286_MSTLINKSEL_AUTO | priv->route_mask);
> > > + max9286_write(priv, 0x0b, link_order);
> > > + max9286_write(priv, 0x69, 0xf & ~priv->route_mask);
> > > +
> > > + v4l2_subdev_unlock_state(state);
> > > +}
> > > +
> > > /* -----------------------------------------------------------------------------
> > > * V4L2 Subdev
> > > */
> > > @@ -701,6 +756,8 @@ static int max9286_s_stream(struct v4l2_subdev *sd, int enable)
> > > int ret;
> > >
> > > if (enable) {
> > > + max9286_config_links(priv);
> > > +
> > > /*
> > > * The frame sync between cameras is transmitted across the
> > > * reverse channel as GPIO. We must open all channels while
> > > @@ -1109,32 +1166,6 @@ static void max9286_v4l2_unregister(struct max9286_priv *priv)
> > >
> > > static int max9286_setup(struct max9286_priv *priv)
> > > {
> > > - /*
> > > - * Link ordering values for all enabled links combinations. Orders must
> > > - * be assigned sequentially from 0 to the number of enabled links
> > > - * without leaving any hole for disabled links. We thus assign orders to
> > > - * enabled links first, and use the remaining order values for disabled
> > > - * links are all links must have a different order value;
> > > - */
> > > - static const u8 link_order[] = {
> > > - (3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xxxx */
> > > - (3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xxx0 */
> > > - (3 << 6) | (2 << 4) | (0 << 2) | (1 << 0), /* xx0x */
> > > - (3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* xx10 */
> > > - (3 << 6) | (0 << 4) | (2 << 2) | (1 << 0), /* x0xx */
> > > - (3 << 6) | (1 << 4) | (2 << 2) | (0 << 0), /* x1x0 */
> > > - (3 << 6) | (1 << 4) | (0 << 2) | (2 << 0), /* x10x */
> > > - (3 << 6) | (1 << 4) | (1 << 2) | (0 << 0), /* x210 */
> > > - (0 << 6) | (3 << 4) | (2 << 2) | (1 << 0), /* 0xxx */
> > > - (1 << 6) | (3 << 4) | (2 << 2) | (0 << 0), /* 1xx0 */
> > > - (1 << 6) | (3 << 4) | (0 << 2) | (2 << 0), /* 1x0x */
> > > - (2 << 6) | (3 << 4) | (1 << 2) | (0 << 0), /* 2x10 */
> > > - (1 << 6) | (0 << 4) | (3 << 2) | (2 << 0), /* 10xx */
> > > - (2 << 6) | (1 << 4) | (3 << 2) | (0 << 0), /* 21x0 */
> > > - (2 << 6) | (1 << 4) | (0 << 2) | (3 << 0), /* 210x */
> > > - (3 << 6) | (2 << 4) | (1 << 2) | (0 << 0), /* 3210 */
> > > - };
> > > -
> > > /*
> > > * Set the I2C bus speed.
> > > *
> > > @@ -1144,13 +1175,7 @@ static int max9286_setup(struct max9286_priv *priv)
> > > max9286_configure_i2c(priv, true);
> > > max9286_reverse_channel_setup(priv, priv->init_rev_chan_mv);
> > >
> > > - /*
> > > - * Enable GMSL links, mask unused ones and autodetect link
> > > - * used as CSI clock source.
> > > - */
> > > - max9286_write(priv, 0x00, MAX9286_MSTLINKSEL_AUTO | priv->route_mask);
> > > - max9286_write(priv, 0x0b, link_order[priv->route_mask]);
> > > - max9286_write(priv, 0x69, (0xf & ~priv->route_mask));
> > > + max9286_config_links(priv);
> >
> > We could actually skip this, and only call
> >
> > max9286_write(priv, 0x00, MAX9286_MSTLINKSEL_AUTO | priv->route_mask);
> >
> > to enable the links. The link order and link masking is only needed when
> > starting the streams, which is done by calling max9286_config_links() in
> > max9286_s_stream().
> >
> > >
> > > /*
> > > * Video format setup:
> > > @@ -1324,12 +1349,6 @@ static int max9286_init(struct device *dev)
> > > if (ret)
> > > return ret;
> > >
> > > - ret = max9286_setup(priv);
> > > - if (ret) {
> > > - dev_err(dev, "Unable to setup max9286\n");
> > > - goto err_poc_disable;
> > > - }
> > > -
> > > /*
> > > * Register all V4L2 interactions for the MAX9286 and notifiers for
> > > * any subdevices connected.
> > > @@ -1340,6 +1359,12 @@ static int max9286_init(struct device *dev)
> > > goto err_poc_disable;
> > > }
> > >
> > > + ret = max9286_setup(priv);
> > > + if (ret) {
> > > + dev_err(dev, "Unable to setup max9286\n");
> > > + goto err_poc_disable;
> > > + }
> > > +
> >
> > And with the above change, I think you can keep the max9286_setup() call
> > where it was.
> >
> > > ret = max9286_i2c_mux_init(priv);
> > > if (ret) {
> > > dev_err(dev, "Unable to initialize I2C multiplexer\n");
--
Regards,
Laurent Pinchart
