Hi Hans,
Thanks for your feedback.
On 2019-03-11 11:53:01 +0100, Hans Verkuil wrote:
> On 2/18/19 11:15 AM, Niklas Söderlund wrote:
> > Restart the CSI-2 link if the CSI-2 receiver detects an error during
> > reception. The driver did nothing when a link error happened and the
> > data flow simply stopped without the user knowing why.
> >
> > Change the driver to try and recover from errors by restarting the link
> > and informing the user that something is not right. For obvious reasons
> > it's not possible to recover from all errors (video source disconnected
> > for example) but in such cases the user is at least informed of the
> > error and the same behavior of the stopped data flow is retained.
>
> What you really would like to have is that when a CSI error is detected,
> the CSI driver can ask upstream whether or not a disconnect has taken place.
>
> If that was the case, then there is no point in restarting the CSI.
>
> While a disconnect is very uncommon for a sensor, it is of course perfectly
> normal if an HDMI-to-CSI bridge was connected to the CSI port.
>
> Unfortunately, we don't have such functionality, but perhaps this is something
> to think about?
I think your idea sounds good and that such a functionality could be
useful. I have a feeling such a functionality could be related to
notifications?
>
> This does mean, however, that I don't like the dev_err since it doesn't have
> to be an error. I would suggest replacing the first dev_err by dev_info and
> the second by dev_warn.
With the background you provides I agree that they should not be
dev_err. I will update as you suggest for the next version, thanks.
>
> Regards,
>
> Hans
>
> >
> > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
> > ---
> > drivers/media/platform/rcar-vin/rcar-csi2.c | 52 ++++++++++++++++++++-
> > 1 file changed, 51 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c b/drivers/media/platform/rcar-vin/rcar-csi2.c
> > index f90b380478775015..0506fe4106d5c012 100644
> > --- a/drivers/media/platform/rcar-vin/rcar-csi2.c
> > +++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
> > @@ -84,6 +84,9 @@ struct rcar_csi2;
> >
> > /* Interrupt Enable */
> > #define INTEN_REG 0x30
> > +#define INTEN_INT_AFIFO_OF BIT(27)
> > +#define INTEN_INT_ERRSOTHS BIT(4)
> > +#define INTEN_INT_ERRSOTSYNCHS BIT(3)
> >
> > /* Interrupt Source Mask */
> > #define INTCLOSE_REG 0x34
> > @@ -540,6 +543,10 @@ static int rcsi2_start_receiver(struct rcar_csi2 *priv)
> > if (mbps < 0)
> > return mbps;
> >
> > + /* Enable interrupts. */
> > + rcsi2_write(priv, INTEN_REG, INTEN_INT_AFIFO_OF | INTEN_INT_ERRSOTHS
> > + | INTEN_INT_ERRSOTSYNCHS);
> > +
> > /* Init */
> > rcsi2_write(priv, TREF_REG, TREF_TREF);
> > rcsi2_write(priv, PHTC_REG, 0);
> > @@ -702,6 +709,43 @@ static const struct v4l2_subdev_ops rcar_csi2_subdev_ops = {
> > .pad = &rcar_csi2_pad_ops,
> > };
> >
> > +static irqreturn_t rcsi2_irq(int irq, void *data)
> > +{
> > + struct rcar_csi2 *priv = data;
> > + u32 status, err_status;
> > +
> > + status = rcsi2_read(priv, INTSTATE_REG);
> > + err_status = rcsi2_read(priv, INTERRSTATE_REG);
> > +
> > + if (!status)
> > + return IRQ_HANDLED;
> > +
> > + rcsi2_write(priv, INTSTATE_REG, status);
> > +
> > + if (!err_status)
> > + return IRQ_HANDLED;
> > +
> > + rcsi2_write(priv, INTERRSTATE_REG, err_status);
> > +
> > + dev_err(priv->dev, "Transfer error, restarting CSI-2 receiver\n");
> > +
> > + return IRQ_WAKE_THREAD;
> > +}
> > +
> > +static irqreturn_t rcsi2_irq_thread(int irq, void *data)
> > +{
> > + struct rcar_csi2 *priv = data;
> > +
> > + mutex_lock(&priv->lock);
> > + rcsi2_stop(priv);
> > + usleep_range(1000, 2000);
> > + if (rcsi2_start(priv))
> > + dev_err(priv->dev, "Failed to restart CSI-2 receiver\n");
> > + mutex_unlock(&priv->lock);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > /* -----------------------------------------------------------------------------
> > * Async handling and registration of subdevices and links.
> > */
> > @@ -982,7 +1026,7 @@ static int rcsi2_probe_resources(struct rcar_csi2 *priv,
> > struct platform_device *pdev)
> > {
> > struct resource *res;
> > - int irq;
> > + int irq, ret;
> >
> > res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > priv->base = devm_ioremap_resource(&pdev->dev, res);
> > @@ -993,6 +1037,12 @@ static int rcsi2_probe_resources(struct rcar_csi2 *priv,
> > if (irq < 0)
> > return irq;
> >
> > + ret = devm_request_threaded_irq(&pdev->dev, irq, rcsi2_irq,
> > + rcsi2_irq_thread, IRQF_SHARED,
> > + KBUILD_MODNAME, priv);
> > + if (ret)
> > + return ret;
> > +
> > priv->rstc = devm_reset_control_get(&pdev->dev, NULL);
> > if (IS_ERR(priv->rstc))
> > return PTR_ERR(priv->rstc);
> >
>
--
Regards,
Niklas Söderlund
