watchdog: meson: Enable meson SoC specific data

With this patch we refactor the driver code to enable watchdog support
for all platforms based on Amlogic meson SoCs.
The new default timeout is also now chosen considering the maximum
timeout allowed by the SoC.
Signed-off-by: Carlo Caione <carlo@endlessm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/meson_wdt.c

@@ -18,6 +18,7 @@
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/types.h>
 #include <linux/watchdog.h>
@@ -25,30 +26,42 @@
 #define DRV_NAME		"meson_wdt"
 
 #define MESON_WDT_TC		0x00
-#define MESON_WDT_TC_EN		BIT(22)
-#define MESON_WDT_TC_TM_MASK	0x3fffff
 #define MESON_WDT_DC_RESET	(3 << 24)
 
 #define MESON_WDT_RESET		0x04
 
 #define MESON_WDT_TIMEOUT	30
 #define MESON_WDT_MIN_TIMEOUT	1
-#define MESON_WDT_MAX_TIMEOUT	(MESON_WDT_TC_TM_MASK / 100000)
 
-#define MESON_SEC_TO_TC(s)	((s) * 100000)
+#define MESON_SEC_TO_TC(s, c)	((s) * (c))
 
 static bool nowayout = WATCHDOG_NOWAYOUT;
 static unsigned int timeout = MESON_WDT_TIMEOUT;
 
+struct meson_wdt_data {
+	unsigned int enable;
+	unsigned int terminal_count_mask;
+	unsigned int count_unit;
+};
+
+static struct meson_wdt_data meson6_wdt_data = {
+	.enable			= BIT(22),
+	.terminal_count_mask	= 0x3fffff,
+	.count_unit		= 100000, /* 10 us */
+};
+
 struct meson_wdt_dev {
 	struct watchdog_device wdt_dev;
 	void __iomem *wdt_base;
+	const struct meson_wdt_data *data;
 };
 
 static int meson_wdt_restart(struct watchdog_device *wdt_dev)
 {
 	struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
-	u32 tc_reboot = MESON_WDT_DC_RESET | MESON_WDT_TC_EN;
+	u32 tc_reboot = MESON_WDT_DC_RESET;
+
+	tc_reboot |= meson_wdt->data->enable;
 
 	while (1) {
 		writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC);
@@ -74,8 +87,8 @@ static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev,
 	u32 reg;
 
 	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
-	reg &= ~MESON_WDT_TC_TM_MASK;
-	reg |= MESON_SEC_TO_TC(timeout);
+	reg &= ~meson_wdt->data->terminal_count_mask;
+	reg |= MESON_SEC_TO_TC(timeout, meson_wdt->data->count_unit);
 	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
 }
 
@@ -96,7 +109,7 @@ static int meson_wdt_stop(struct watchdog_device *wdt_dev)
 	u32 reg;
 
 	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
-	reg &= ~MESON_WDT_TC_EN;
+	reg &= ~meson_wdt->data->enable;
 	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
 
 	return 0;
@@ -111,7 +124,7 @@ static int meson_wdt_start(struct watchdog_device *wdt_dev)
 	meson_wdt_ping(wdt_dev);
 
 	reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
-	reg |= MESON_WDT_TC_EN;
+	reg |= meson_wdt->data->enable;
 	writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
 
 	return 0;
@@ -133,10 +146,17 @@ static const struct watchdog_ops meson_wdt_ops = {
 	.restart        = meson_wdt_restart,
 };
 
+static const struct of_device_id meson_wdt_dt_ids[] = {
+	{ .compatible = "amlogic,meson6-wdt", .data = &meson6_wdt_data },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids);
+
 static int meson_wdt_probe(struct platform_device *pdev)
 {
 	struct resource *res;
 	struct meson_wdt_dev *meson_wdt;
+	const struct of_device_id *of_id;
 	int err;
 
 	meson_wdt = devm_kzalloc(&pdev->dev, sizeof(*meson_wdt), GFP_KERNEL);
@@ -148,12 +168,22 @@ static int meson_wdt_probe(struct platform_device *pdev)
 	if (IS_ERR(meson_wdt->wdt_base))
 		return PTR_ERR(meson_wdt->wdt_base);
 
+	of_id = of_match_device(meson_wdt_dt_ids, &pdev->dev);
+	if (!of_id) {
+		dev_err(&pdev->dev, "Unable to initialize WDT data\n");
+		return -ENODEV;
+	}
+	meson_wdt->data = of_id->data;
+
 	meson_wdt->wdt_dev.parent = &pdev->dev;
 	meson_wdt->wdt_dev.info = &meson_wdt_info;
 	meson_wdt->wdt_dev.ops = &meson_wdt_ops;
-	meson_wdt->wdt_dev.timeout = MESON_WDT_TIMEOUT;
-	meson_wdt->wdt_dev.max_timeout = MESON_WDT_MAX_TIMEOUT;
+	meson_wdt->wdt_dev.max_timeout =
+		meson_wdt->data->terminal_count_mask / meson_wdt->data->count_unit;
 	meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT;
+	meson_wdt->wdt_dev.timeout = min_t(unsigned int,
+					   MESON_WDT_TIMEOUT,
+					   meson_wdt->wdt_dev.max_timeout);
 
 	watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt);
 
@@ -191,12 +221,6 @@ static void meson_wdt_shutdown(struct platform_device *pdev)
 	meson_wdt_stop(&meson_wdt->wdt_dev);
 }
 
-static const struct of_device_id meson_wdt_dt_ids[] = {
-	{ .compatible = "amlogic,meson6-wdt" },
-	{ /* sentinel */ }
-};
-MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids);
-
 static struct platform_driver meson_wdt_driver = {
 	.probe		= meson_wdt_probe,
 	.remove		= meson_wdt_remove,