On Aug 01, 2023 at 17:16:41 +0300, Tomi Valkeinen wrote:

On 31/07/2023 11:29, Jai Luthra wrote:

quoted

From: Pratyush Yadav <redacted>

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 <redacted>
Signed-off-by: Jai Luthra <redacted>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
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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