Re: [PATCH v8 09/16] media: cadence: csi2rx: Soft reset the streams before starting capture

From: Jai Luthra
Date: Thu Aug 03 2023 - 07:20:16 EST


On Aug 01, 2023 at 17:16:41 +0300, Tomi Valkeinen wrote:
> On 31/07/2023 11:29, Jai Luthra wrote:
> > From: Pratyush Yadav <p.yadav@xxxxxx>
> >
> > This resets the stream state machines and FIFOs, giving them a clean
> > slate. On J721E if the streams are not reset before starting the
> > capture, the captured frame gets wrapped around vertically on every run
> > after the first.
> >
> > Signed-off-by: Pratyush Yadav <p.yadav@xxxxxx>
> > Signed-off-by: Jai Luthra <j-luthra@xxxxxx>
> > Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> > ---
> > v7->v8: No change
> >
> > drivers/media/platform/cadence/cdns-csi2rx.c | 11 +++++++++++
> > 1 file changed, 11 insertions(+)
> >
> > diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
> > index 2a80c66fb547..30cdc260b46a 100644
> > --- a/drivers/media/platform/cadence/cdns-csi2rx.c
> > +++ b/drivers/media/platform/cadence/cdns-csi2rx.c
> > @@ -40,6 +40,7 @@
> > #define CSI2RX_STREAM_BASE(n) (((n) + 1) * 0x100)
> > #define CSI2RX_STREAM_CTRL_REG(n) (CSI2RX_STREAM_BASE(n) + 0x000)
> > +#define CSI2RX_STREAM_CTRL_SOFT_RST BIT(4)
> > #define CSI2RX_STREAM_CTRL_START BIT(0)
> > #define CSI2RX_STREAM_DATA_CFG_REG(n) (CSI2RX_STREAM_BASE(n) + 0x008)
> > @@ -138,12 +139,22 @@ struct csi2rx_priv *v4l2_subdev_to_csi2rx(struct v4l2_subdev *subdev)
> > static void csi2rx_reset(struct csi2rx_priv *csi2rx)
> > {
> > + unsigned int i;
> > +
> > writel(CSI2RX_SOFT_RESET_PROTOCOL | CSI2RX_SOFT_RESET_FRONT,
> > csi2rx->base + CSI2RX_SOFT_RESET_REG);
> > udelay(10);
> > writel(0, csi2rx->base + CSI2RX_SOFT_RESET_REG);
> > +
> > + /* Reset individual streams. */
> > + for (i = 0; i < csi2rx->max_streams; i++) {
> > + writel(CSI2RX_STREAM_CTRL_SOFT_RST,
> > + csi2rx->base + CSI2RX_STREAM_CTRL_REG(i));
> > + usleep_range(10, 20);
> > + writel(0, csi2rx->base + CSI2RX_STREAM_CTRL_REG(i));
> > + }
>
> Do you have to do it like this? Or would it be fine to set the reset bit for
> all stream regs, then sleep, then clear the reset bit from all stream regs?
> Or going even further, can you set the CSI2RX_SOFT_RESET_REG and all
> CSI2RX_STREAM_CTRL_REG regs, then sleep, and then clear them all?

You're right I think that should work, and would be much cleaner. Will
fix.

>
> Tomi
>

--
Thanks,
Jai

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