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/drivers/watchdog/s5p_wdt.c

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2012 Samsung Electronics
+ * Minkyu Kang <mk7.kang@samsung.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/arch/watchdog.h>
+
+#define PRESCALER_VAL 255
+
+void wdt_stop(void)
+{
+	struct s5p_watchdog *wdt =
+		(struct s5p_watchdog *)samsung_get_base_watchdog();
+	unsigned int wtcon;
+
+	wtcon = readl(&wdt->wtcon);
+	wtcon &= ~(WTCON_EN | WTCON_INT | WTCON_RESET);
+
+	writel(wtcon, &wdt->wtcon);
+}
+
+void wdt_start(unsigned int timeout)
+{
+	struct s5p_watchdog *wdt =
+		(struct s5p_watchdog *)samsung_get_base_watchdog();
+	unsigned int wtcon;
+
+	wdt_stop();
+
+	wtcon = readl(&wdt->wtcon);
+	wtcon |= (WTCON_EN | WTCON_CLK(WTCON_CLK_128));
+	wtcon &= ~WTCON_INT;
+	wtcon |= WTCON_RESET;
+	wtcon |= WTCON_PRESCALER(PRESCALER_VAL);
+
+	writel(timeout, &wdt->wtdat);
+	writel(timeout, &wdt->wtcnt);
+	writel(wtcon, &wdt->wtcon);
+}