avionic design with actual uboot and tooling

submodule of avionic design uboot bootloader and with included tools to
get you started , read readme.md and readme-tk1-loader.md

u-boot/arch/sh/cpu/sh4/watchdog.c

@@ -0,0 +1,62 @@
+/*
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/processor.h>
+#include <asm/system.h>
+#include <asm/io.h>
+
+#define WDT_BASE	WTCNT
+
+#define WDT_WD		(1 << 6)
+#define WDT_RST_P	(0)
+#define WDT_RST_M	(1 << 5)
+#define WDT_ENABLE	(1 << 7)
+
+#if defined(CONFIG_WATCHDOG)
+static unsigned char csr_read(void)
+{
+	return inb(WDT_BASE + 0x04);
+}
+
+static void cnt_write(unsigned char value)
+{
+	outl((unsigned short)value | 0x5A00, WDT_BASE + 0x00);
+}
+
+static void csr_write(unsigned char value)
+{
+	outl((unsigned short)value | 0xA500, WDT_BASE + 0x04);
+}
+
+void watchdog_reset(void)
+{
+	outl(0x55000000, WDT_BASE + 0x08);
+}
+
+int watchdog_init(void)
+{
+	/* Set overflow time*/
+	cnt_write(0);
+	/* Power on reset */
+	csr_write(WDT_WD|WDT_RST_P|WDT_ENABLE);
+
+	return 0;
+}
+
+int watchdog_disable(void)
+{
+	csr_write(csr_read() & ~WDT_ENABLE);
+	return 0;
+}
+#endif
+
+void reset_cpu(unsigned long ignored)
+{
+	/* Address error with SR.BL=1 first. */
+	trigger_address_error();
+
+	while (1)
+		;
+}