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/arm/mach-rockchip/rk_timer.c

@@ -0,0 +1,48 @@
+/*
+ * (C) Copyright 2015 Rockchip Electronics Co., Ltd
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#include <asm/arch/timer.h>
+#include <asm/io.h>
+#include <common.h>
+#include <linux/types.h>
+
+struct rk_timer * const timer_ptr = (void *)CONFIG_SYS_TIMER_BASE;
+
+static uint64_t rockchip_get_ticks(void)
+{
+	uint64_t timebase_h, timebase_l;
+
+	timebase_l = readl(&timer_ptr->timer_curr_value0);
+	timebase_h = readl(&timer_ptr->timer_curr_value1);
+
+	return timebase_h << 32 | timebase_l;
+}
+
+static uint64_t usec_to_tick(unsigned int usec)
+{
+	uint64_t tick = usec;
+	tick *= CONFIG_SYS_TIMER_RATE / (1000 * 1000);
+	return tick;
+}
+
+void rockchip_udelay(unsigned int usec)
+{
+	uint64_t tmp;
+
+	/* get timestamp */
+	tmp = rockchip_get_ticks() + usec_to_tick(usec);
+
+	/* loop till event */
+	while (rockchip_get_ticks() < tmp+1)
+		;
+}
+
+void rockchip_timer_init(void)
+{
+	writel(0xffffffff, &timer_ptr->timer_load_count0);
+	writel(0xffffffff, &timer_ptr->timer_load_count1);
+	writel(1, &timer_ptr->timer_ctrl_reg);
+}