[1/2] media: rcar-fcp: Add rcar_fcp_soft_reset()

Commit Message

Jacopo Mondi Dec. 19, 2024, 6:38 p.m. UTC

Add a function to perform soft reset of the FCP. The function
needs to be called to correctly turn off the FCP operations before
disabling the module.

This function is intended to support the correct stop procedure of the
VSPX-FCPVX pair according to section "62.3.7.3 Reset Operation" of
the R-Car V4H User Manual at revision r120.

Signed-off-by: Jacopo Mondi <[e-mail]>
---
 drivers/media/platform/renesas/rcar-fcp.c | 41 +++++++++++++++++++++++++++++++
 include/media/rcar-fcp.h                  |  5 ++++
 2 files changed, 46 insertions(+)

Patch

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__ */