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/cpu/armv7/omap-common/timer.c

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+/*
+ * (C) Copyright 2008
+ * Texas Instruments
+ *
+ * Richard Woodruff <r-woodruff2@ti.com>
+ * Syed Moahmmed Khasim <khasim@ti.com>
+ *
+ * (C) Copyright 2002
+ * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
+ * Marius Groeger <mgroeger@sysgo.de>
+ * Alex Zuepke <azu@sysgo.de>
+ *
+ * (C) Copyright 2002
+ * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/arch/cpu.h>
+#include <asm/arch/clock.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static struct gptimer *timer_base = (struct gptimer *)CONFIG_SYS_TIMERBASE;
+
+/*
+ * Nothing really to do with interrupts, just starts up a counter.
+ */
+
+#define TIMER_CLOCK		(V_SCLK / (2 << CONFIG_SYS_PTV))
+#define TIMER_OVERFLOW_VAL	0xffffffff
+#define TIMER_LOAD_VAL		0
+
+int timer_init(void)
+{
+	/* start the counter ticking up, reload value on overflow */
+	writel(TIMER_LOAD_VAL, &timer_base->tldr);
+	/* enable timer */
+	writel((CONFIG_SYS_PTV << 2) | TCLR_PRE | TCLR_AR | TCLR_ST,
+		&timer_base->tclr);
+
+	return 0;
+}
+
+/*
+ * timer without interrupts
+ */
+ulong get_timer(ulong base)
+{
+	return get_timer_masked() - base;
+}
+
+/* delay x useconds */
+void __udelay(unsigned long usec)
+{
+	long tmo = usec * (TIMER_CLOCK / 1000) / 1000;
+	unsigned long now, last = readl(&timer_base->tcrr);
+
+	while (tmo > 0) {
+		now = readl(&timer_base->tcrr);
+		if (last > now) /* count up timer overflow */
+			tmo -= TIMER_OVERFLOW_VAL - last + now + 1;
+		else
+			tmo -= now - last;
+		last = now;
+	}
+}
+
+ulong get_timer_masked(void)
+{
+	/* current tick value */
+	ulong now = readl(&timer_base->tcrr) / (TIMER_CLOCK / CONFIG_SYS_HZ);
+
+	if (now >= gd->arch.lastinc) {	/* normal mode (non roll) */
+		/* move stamp fordward with absoulte diff ticks */
+		gd->arch.tbl += (now - gd->arch.lastinc);
+	} else {	/* we have rollover of incrementer */
+		gd->arch.tbl += ((TIMER_OVERFLOW_VAL / (TIMER_CLOCK /
+				CONFIG_SYS_HZ)) - gd->arch.lastinc) + now;
+	}
+	gd->arch.lastinc = now;
+	return gd->arch.tbl;
+}
+
+/*
+ * This function is derived from PowerPC code (read timebase as long long).
+ * On ARM it just returns the timer value.
+ */
+unsigned long long get_ticks(void)
+{
+	return get_timer(0);
+}
+
+/*
+ * This function is derived from PowerPC code (timebase clock frequency).
+ * On ARM it returns the number of timer ticks per second.
+ */
+ulong get_tbclk(void)
+{
+	return CONFIG_SYS_HZ;
+}