[PATCH v9 07/13] media: cadence: csi2rx: Soft reset the streams before starting capture

Jai Luthra
2023-08-11T10:48:41Z

From: Pratyush Yadav <p.yadav@ti.com>

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@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Jai Luthra <j-luthra@ti.com>
---
Changes from v8:
- Simplify reset sequence, minimizing delays

drivers/media/platform/cadence/cdns-csi2rx.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
index 933edec89520..b57e0c3b1944 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)
@@ -134,12 +135,23 @@ struct csi2rx_priv *v4l2_subdev_to_csi2rx(struct v4l2_subdev *subdev)

static void csi2rx_reset(struct csi2rx_priv *csi2rx)
{
+ unsigned int i;
+
+ /* Reset module */
writel(CSI2RX_SOFT_RESET_PROTOCOL | CSI2RX_SOFT_RESET_FRONT,
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));
+ }

- udelay(10);
+ usleep_range(10, 20);

+ /* Clear resets */
writel(0, csi2rx->base + CSI2RX_SOFT_RESET_REG);
+ for (i = 0; i < csi2rx->max_streams; i++)
+ writel(0, csi2rx->base + CSI2RX_STREAM_CTRL_REG(i));
}

static int csi2rx_configure_ext_dphy(struct csi2rx_priv *csi2rx)

--
2.41.0