watchdog: imx: Support set timeout by wdt command

After "4b969dea watchdog: imx: Add DM support", the imx watchdog
can be started by wdt command. But the imx watchdog driver only
support start with the default timeout.

This commit adds the support for setting the timeout which pass from
the wdt command into the imx watchdog. If the timeout out of the
valid range(0.5~128s), start the watchdog with a timeout within the
valid range and the timeout is the one which closest to the passed
timeout.
Signed-off-by: NYuezhang.Mo <yuezhang.mo@sony.com>
Reviewed-by: NAndy.Wu <Andy.Wu@sony.com>
Reviewed-by: Nstefano Babic <sbabic@denx.de>

drivers/watchdog/imx_watchdog.c

@@ -16,6 +16,10 @@
 #include <asm/arch/immap_lsch2.h>
 #endif
 #include <fsl_wdog.h>
+#include <div64.h>
+
+#define TIMEOUT_MAX	128000
+#define TIMEOUT_MIN	500
 
 static void imx_watchdog_expire_now(struct watchdog_regs *wdog, bool ext_reset)
 {
@@ -57,9 +61,9 @@ static void imx_watchdog_reset(struct watchdog_regs *wdog)
 #endif /* CONFIG_WATCHDOG_RESET_DISABLE*/
 }
 
-static void imx_watchdog_init(struct watchdog_regs *wdog, bool ext_reset)
+static void imx_watchdog_init(struct watchdog_regs *wdog, bool ext_reset,
+			      u64 timeout)
 {
-	u16 timeout;
 	u16 wcr;
 
 	/*
@@ -70,7 +74,11 @@ static void imx_watchdog_init(struct watchdog_regs *wdog, bool ext_reset)
 #ifndef CONFIG_WATCHDOG_TIMEOUT_MSECS
 #define CONFIG_WATCHDOG_TIMEOUT_MSECS 128000
 #endif
-	timeout = (CONFIG_WATCHDOG_TIMEOUT_MSECS / 500) - 1;
+
+	timeout = max_t(u64, timeout, TIMEOUT_MIN);
+	timeout = min_t(u64, timeout, TIMEOUT_MAX);
+	timeout = lldiv(timeout, 500) - 1;
+
 #ifdef CONFIG_FSL_LSCH2
 	wcr = (WCR_WDA | WCR_SRS | WCR_WDE) << 8 | timeout;
 #else
@@ -95,7 +103,7 @@ void hw_watchdog_init(void)
 {
 	struct watchdog_regs *wdog = (struct watchdog_regs *)WDOG1_BASE_ADDR;
 
-	imx_watchdog_init(wdog, true);
+	imx_watchdog_init(wdog, true, CONFIG_WATCHDOG_TIMEOUT_MSECS);
 }
 #else
 struct imx_wdt_priv {
@@ -126,7 +134,7 @@ static int imx_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
 {
 	struct imx_wdt_priv *priv = dev_get_priv(dev);
 
-	imx_watchdog_init(priv->base, priv->ext_reset);
+	imx_watchdog_init(priv->base, priv->ext_reset, timeout);
 
 	return 0;
 }