[5/6] watchdog: rzv2h_wdt: Add support to retrieve the bootstatus information

Commit Message

Prabhakar Dec. 18, 2024, 12:34 a.m. UTC

From: Lad Prabhakar <[e-mail]>

On the RZ/V2H(P) SoC we can determine if the current boot is due to
`Power-on-Reset` or due to the `Watchdog`. The information used to
determine this is present on the CPG block.

The CPG_ERROR_RSTm(m = 2 - 8) registers are set in response to an error
interrupt causing an reset. CPG_ERROR_RST2[ERROR_RST0/1/2] is set if there
was an underflow/overflow on WDT1 causing an error interrupt.

To fetch this information from CPG block `syscon` is used and bootstatus
field in the watchdog device is updated based on the
CPG_ERROR_RST2[ERROR_RST0/1/2] bit. Upon consumig
CPG_ERROR_RST2[ERROR_RST0/1/2] bit we clear it.

Signed-off-by: Lad Prabhakar <[e-mail]>
---
 drivers/watchdog/rzv2h_wdt.c | 48 +++++++++++++++++++++++++++++++++++-
 1 file changed, 47 insertions(+), 1 deletion(-)

Patch

diff --git a/drivers/watchdog/rzv2h_wdt.c b/drivers/watchdog/rzv2h_wdt.c
index 8defd0241213..5ba5965ac170 100644
--- a/drivers/watchdog/rzv2h_wdt.c
+++ b/drivers/watchdog/rzv2h_wdt.c
@@ -4,14 +4,17 @@ 
  *
  * Copyright (C) 2024 Renesas Electronics Corporation.
  */
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/regmap.h>
 #include <linux/reset.h>
 #include <linux/units.h>
 #include <linux/watchdog.h>
@@ -40,6 +43,9 @@ 
 
 #define WDT_DEFAULT_TIMEOUT	60U
 
+#define CPG_ERROR_RST2(x)	BIT(x)
+#define CPG_ERROR_RST2_WEN(x)	BIT((x) + 16)
+
 static bool nowayout = WATCHDOG_NOWAYOUT;
 module_param(nowayout, bool, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
@@ -139,6 +145,11 @@  static const struct watchdog_info rzv2h_wdt_ident = {
 	.identity = "Renesas RZ/V2H WDT Watchdog",
 };
 
+static const struct watchdog_info rzv2h_wdt_ident_card_reset = {
+	.options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_CARDRESET,
+	.identity = "Renesas RZ/V2H WDT Watchdog",
+};
+
 static int rzv2h_wdt_restart(struct watchdog_device *wdev,
 			     unsigned long action, void *data)
 {
@@ -206,9 +217,40 @@  static const struct watchdog_ops rzv2h_wdt_ops = {
 static int rzv2h_wdt_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
 	struct rzv2h_wdt_priv *priv;
+	unsigned int bootstatus = 0;
+	bool cardreset = false;
+	struct regmap *syscon;
 	int ret;
 
+	/* Do not error out to maintain old DT compatibility */
+	syscon = syscon_regmap_lookup_by_phandle(np, "renesas,r9a09g057-syscon-wdt-errorrst");
+	if (!IS_ERR(syscon)) {
+		struct of_phandle_args args;
+		u32 reg;
+
+		ret = of_parse_phandle_with_fixed_args(np, "renesas,r9a09g057-syscon-wdt-errorrst",
+						       2, 0, &args);
+		if (ret)
+			return ret;
+
+		ret = regmap_read(syscon, args.args[0], &reg);
+		if (ret)
+			return -EINVAL;
+
+		if (reg & CPG_ERROR_RST2(args.args[1])) {
+			ret = regmap_write(syscon, args.args[0],
+					   CPG_ERROR_RST2(args.args[1]) |
+					   CPG_ERROR_RST2_WEN(args.args[1]));
+			if (ret)
+				return -EINVAL;
+		}
+		cardreset = true;
+		bootstatus = reg & CPG_ERROR_RST2(args.args[1]) ? WDIOF_CARDRESET : 0;
+		regmap_read(syscon, args.args[0], &reg);
+	}
+
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
@@ -240,9 +282,13 @@  static int rzv2h_wdt_probe(struct platform_device *pdev)
 
 	priv->wdev.min_timeout = 1;
 	priv->wdev.timeout = WDT_DEFAULT_TIMEOUT;
-	priv->wdev.info = &rzv2h_wdt_ident;
+	if (!cardreset)
+		priv->wdev.info = &rzv2h_wdt_ident;
+	else
+		priv->wdev.info = &rzv2h_wdt_ident_card_reset;
 	priv->wdev.ops = &rzv2h_wdt_ops;
 	priv->wdev.parent = dev;
+	priv->wdev.bootstatus = bootstatus;
 	watchdog_set_drvdata(&priv->wdev, priv);
 	watchdog_set_nowayout(&priv->wdev, nowayout);
 	watchdog_stop_on_unregister(&priv->wdev);