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/arm920t/s3c24x0/speed.c

@@ -0,0 +1,102 @@
+/*
+ * (C) Copyright 2001-2004
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ * (C) Copyright 2002
+ * David Mueller, ELSOFT AG, d.mueller@elsoft.ch
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+/* This code should work for both the S3C2400 and the S3C2410
+ * as they seem to have the same PLL and clock machinery inside.
+ * The different address mapping is handled by the s3c24xx.h files below.
+ */
+
+#include <common.h>
+#ifdef CONFIG_S3C24X0
+
+#include <asm/io.h>
+#include <asm/arch/s3c24x0_cpu.h>
+
+#define MPLL 0
+#define UPLL 1
+
+/* ------------------------------------------------------------------------- */
+/* NOTE: This describes the proper use of this file.
+ *
+ * CONFIG_SYS_CLK_FREQ should be defined as the input frequency of the PLL.
+ *
+ * get_FCLK(), get_HCLK(), get_PCLK() and get_UCLK() return the clock of
+ * the specified bus in HZ.
+ */
+/* ------------------------------------------------------------------------- */
+
+static ulong get_PLLCLK(int pllreg)
+{
+	struct s3c24x0_clock_power *clk_power = s3c24x0_get_base_clock_power();
+	ulong r, m, p, s;
+
+	if (pllreg == MPLL)
+		r = readl(&clk_power->mpllcon);
+	else if (pllreg == UPLL)
+		r = readl(&clk_power->upllcon);
+	else
+		hang();
+
+	m = ((r & 0xFF000) >> 12) + 8;
+	p = ((r & 0x003F0) >> 4) + 2;
+	s = r & 0x3;
+
+#if defined(CONFIG_S3C2440)
+	if (pllreg == MPLL)
+		return 2 * m * (CONFIG_SYS_CLK_FREQ / (p << s));
+#endif
+	return (CONFIG_SYS_CLK_FREQ * m) / (p << s);
+
+}
+
+/* return FCLK frequency */
+ulong get_FCLK(void)
+{
+	return get_PLLCLK(MPLL);
+}
+
+/* return HCLK frequency */
+ulong get_HCLK(void)
+{
+	struct s3c24x0_clock_power *clk_power = s3c24x0_get_base_clock_power();
+#ifdef CONFIG_S3C2440
+	switch (readl(&clk_power->clkdivn) & 0x6) {
+	default:
+	case 0:
+		return get_FCLK();
+	case 2:
+		return get_FCLK() / 2;
+	case 4:
+		return (readl(&clk_power->camdivn) & (1 << 9)) ?
+			get_FCLK() / 8 : get_FCLK() / 4;
+	case 6:
+		return (readl(&clk_power->camdivn) & (1 << 8)) ?
+			get_FCLK() / 6 : get_FCLK() / 3;
+	}
+#else
+	return (readl(&clk_power->clkdivn) & 2) ? get_FCLK() / 2 : get_FCLK();
+#endif
+}
+
+/* return PCLK frequency */
+ulong get_PCLK(void)
+{
+	struct s3c24x0_clock_power *clk_power = s3c24x0_get_base_clock_power();
+
+	return (readl(&clk_power->clkdivn) & 1) ? get_HCLK() / 2 : get_HCLK();
+}
+
+/* return UCLK frequency */
+ulong get_UCLK(void)
+{
+	return get_PLLCLK(UPLL);
+}
+
+#endif /* CONFIG_S3C24X0 */