linux-kernel - [PATCH 1/3] media: rcar-fcp: Add rcar_fcp_soft

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Message-Id: <20250609-vspx-reset-v1-1-9f17277ff1e2@ideasonboard.com>
Date: Mon, 09 Jun 2025 21:01:42 +0200
From: Jacopo Mondi <jacopo.mondi+renesas@...asonboard.com>
To: Laurent Pinchart <laurent.pinchart@...asonboard.com>, 
 Mauro Carvalho Chehab <mchehab@...nel.org>, 
 Kieran Bingham <kieran.bingham+renesas@...asonboard.com>, 
 Niklas Söderlund <niklas.soderlund@...natech.se>
Cc: linux-media@...r.kernel.org, linux-renesas-soc@...r.kernel.org, 
 linux-kernel@...r.kernel.org, 
 Jacopo Mondi <jacopo.mondi+renesas@...asonboard.com>
Subject: [PATCH 1/3] media: rcar-fcp: Add rcar_fcp_soft_reset()

Add a function to perform soft reset of the FCP.

It is intended to support the correct stop procedure of the VSPX-FCPVX
and VSPD-FCPD pairs according to section "62.3.7.3 Reset Operation" of
the R-Car Hardware Manual at revision 1.20.

Signed-off-by: Jacopo Mondi <jacopo.mondi+renesas@...asonboard.com>
---
 drivers/media/platform/renesas/rcar-fcp.c | 41 +++++++++++++++++++++++++++++++
 include/media/rcar-fcp.h                  |  5 ++++
 2 files changed, 46 insertions(+)

diff --git a/drivers/media/platform/renesas/rcar-fcp.c b/drivers/media/platform/renesas/rcar-fcp.c
index cee9bbce4e3affb2467dbc28142e1ab2304bf5b0..fefeaf77f0122a2d88ac03a5c42a892dc284a163 100644
--- a/drivers/media/platform/renesas/rcar-fcp.c
+++ b/drivers/media/platform/renesas/rcar-fcp.c
@@ -10,6 +10,8 @@
 #include <linux/device.h>
 #include <linux/dma-mapping.h>
 #include <linux/list.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/mutex.h>
@@ -19,14 +21,30 @@
 
 #include <media/rcar-fcp.h>
 
+#define RCAR_FCP_REG_RST		0x0010
+#define RCAR_FCP_REG_RST_SOFTRST	BIT(0)
+#define RCAR_FCP_REG_STA		0x0018
+#define RCAR_FCP_REG_STA_ACT		BIT(0)
+
 struct rcar_fcp_device {
 	struct list_head list;
 	struct device *dev;
+	void __iomem *base;
 };
 
 static LIST_HEAD(fcp_devices);
 static DEFINE_MUTEX(fcp_lock);
 
+static inline u32 rcar_fcp_read(struct rcar_fcp_device *fcp, u32 reg)
+{
+	return ioread32(fcp->base + reg);
+}
+
+static inline void rcar_fcp_write(struct rcar_fcp_device *fcp, u32 reg, u32 val)
+{
+	iowrite32(val, fcp->base + reg);
+}
+
 /* -----------------------------------------------------------------------------
  * Public API
  */
@@ -117,6 +135,25 @@ void rcar_fcp_disable(struct rcar_fcp_device *fcp)
 }
 EXPORT_SYMBOL_GPL(rcar_fcp_disable);
 
+int rcar_fcp_soft_reset(struct rcar_fcp_device *fcp)
+{
+	u32 value;
+	int ret;
+
+	if (!fcp)
+		return 0;
+
+	rcar_fcp_write(fcp, RCAR_FCP_REG_RST, RCAR_FCP_REG_RST_SOFTRST);
+	ret = readl_poll_timeout(fcp->base + RCAR_FCP_REG_STA,
+				 value, !(value & RCAR_FCP_REG_STA_ACT),
+				 0, 100);
+	if (ret)
+		dev_err(fcp->dev, "Failed to soft-reset: %d\n", ret);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rcar_fcp_soft_reset);
+
 /* -----------------------------------------------------------------------------
  * Platform Driver
  */
@@ -131,6 +168,10 @@ static int rcar_fcp_probe(struct platform_device *pdev)
 
 	fcp->dev = &pdev->dev;
 
+	fcp->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(fcp->base))
+		return PTR_ERR(fcp->base);
+
 	dma_set_max_seg_size(fcp->dev, UINT_MAX);
 
 	pm_runtime_enable(&pdev->dev);
diff --git a/include/media/rcar-fcp.h b/include/media/rcar-fcp.h
index 179240fb163bd2e7cc347e559f99bae943bf0e34..6ac9be9f675e667d6482a5a2483963fa52a0c622 100644
--- a/include/media/rcar-fcp.h
+++ b/include/media/rcar-fcp.h
@@ -18,6 +18,7 @@ void rcar_fcp_put(struct rcar_fcp_device *fcp);
 struct device *rcar_fcp_get_device(struct rcar_fcp_device *fcp);
 int rcar_fcp_enable(struct rcar_fcp_device *fcp);
 void rcar_fcp_disable(struct rcar_fcp_device *fcp);
+int rcar_fcp_soft_reset(struct rcar_fcp_device *fcp);
 #else
 static inline struct rcar_fcp_device *rcar_fcp_get(const struct device_node *np)
 {
@@ -33,6 +34,10 @@ static inline int rcar_fcp_enable(struct rcar_fcp_device *fcp)
 	return 0;
 }
 static inline void rcar_fcp_disable(struct rcar_fcp_device *fcp) { }
+static inline int rcar_fcp_soft_reset(struct rcar_fcp_device *fcp)
+{
+	return 0;
+}
 #endif
 
 #endif /* __MEDIA_RCAR_FCP_H__ */

-- 
2.49.0