linux-kernel - [PATCH v7 05/13] media: cadence: csi2rx: Soft reset the streams before starting capture

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Message-ID: <20230314115516.667-6-vaishnav.a@ti.com>
Date:   Tue, 14 Mar 2023 17:25:08 +0530
From:   Vaishnav Achath <vaishnav.a@...com>
To:     <linux-media@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <mripard@...nel.org>, <mchehab@...nel.org>, <robh+dt@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>,
        <laurent.pinchart@...asonboard.com>,
        <sakari.ailus@...ux.intel.com>, <tomi.valkeinen@...asonboard.com>
CC:     <linux-kernel@...r.kernel.org>, <bparrot@...com>,
        <niklas.soderlund+renesas@...natech.se>, <j-luthra@...com>,
        <devarsht@...com>, <praneeth@...com>, <u-kumar1@...com>,
        <vigneshr@...com>, <nm@...com>, <martyn.welch@...labora.com>,
        <vaishnav.a@...com>
Subject: [PATCH v7 05/13] media: cadence: csi2rx: Soft reset the streams before starting capture

From: Pratyush Yadav <p.yadav@...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@...com>
Signed-off-by: Vaishnav Achath <vaishnav.a@...com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
---

(no changes since v5)

Changes in v5:
- Make i unsigned.
- Add Laurent's R-by.

 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 6933626adfc8..8ecd889690b7 100644
--- a/drivers/media/platform/cadence/cdns-csi2rx.c
+++ b/drivers/media/platform/cadence/cdns-csi2rx.c
@@ -39,6 +39,7 @@
 #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)
@@ -135,12 +136,22 @@ 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));
+	}
 }
 
 static int csi2rx_configure_external_dphy(struct csi2rx_priv *csi2rx)
-- 
2.17.1