add watchdog module

Add support for the windowed watchdog.

Signed-off-by: Michael Walle <[email protected]>

Author: mwalle

Makefile

@@ -18,7 +18,7 @@ LDFLAGS = -T linker.ld -mcpu=cortex-m0plus -mlittle-endian -g -nostdlib -mthumb
 LIBS += -lgcc
 
 OBJECTS  = startup.o main.o miniprintf.o uart.o systick.o adc.o vref.o misc.o
-OBJECTS += iomux.o sysctl.o gpio.o cp.o i2c.o nvic.o nvm.o config.o
+OBJECTS += iomux.o sysctl.o gpio.o cp.o i2c.o nvic.o nvm.o config.o wdt.o
 
 DEPS := $(shell find -name '*.d')
 

wdt.c

@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: BSD-2-Clause
+/*
+ * Copyright (c) 2025 Kontron Europe GmbH
+ */
+
+#include "misc.h"
+#include "wdt.h"
+
+#define WWDT_BASE		0x40080000
+
+#define WWDT_PWREN		(WWDT_BASE + 0x0800)
+#define PWREN_KEY		0x26000000
+#define PWREN_ENABLE		BIT(0)
+
+#define WWDT_WWDTCTL0		(WWDT_BASE + 0x1100)
+#define WWDTCTL0_KEY		0xc9000000
+#define WWDTCTL0_CLKDIV(n)	((n) << 0)
+#define WWDTCTL0_PER(n)		((n) << 4)
+
+#define WWDT_WWDTCNTRST		(WWDT_BASE + 0x1108)
+#define WWDTCNTRST_RESTART	0xa7
+
+void wdt_init(void)
+{
+	iow(WWDT_PWREN, PWREN_KEY | PWREN_ENABLE);
+	
+	/* set watchdog timeout to 1s */
+	iow(WWDT_WWDTCTL0, WWDTCTL0_KEY | WWDTCTL0_CLKDIV(0) | WWDTCTL0_PER(3));
+}
+
+void wdt_kick(void)
+{
+	iow(WWDT_WWDTCNTRST, WWDTCNTRST_RESTART);
+}

wdt.h

@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: BSD-2-Clause
+/*
+ * Copyright (c) 2025 Kontron Europe GmbH
+ */
+
+#ifndef __WDT_H
+#define __WDT_H
+
+void wdt_init(void);
+void wdt_kick(void);
+
+#endif /* __WDT_H */