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-at91/arm926ejs/clock.c

@@ -0,0 +1,282 @@
+/*
+ * [origin: Linux kernel linux/arch/arm/mach-at91/clock.c]
+ *
+ * Copyright (C) 2005 David Brownell
+ * Copyright (C) 2005 Ivan Kokshaysky
+ * Copyright (C) 2009 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/arch/hardware.h>
+#include <asm/arch/at91_pmc.h>
+#include <asm/arch/clk.h>
+
+#if !defined(CONFIG_AT91FAMILY)
+# error You need to define CONFIG_AT91FAMILY in your board config!
+#endif
+
+#define EN_PLLB_TIMEOUT	500
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static unsigned long at91_css_to_rate(unsigned long css)
+{
+	switch (css) {
+	case AT91_PMC_MCKR_CSS_SLOW:
+		return CONFIG_SYS_AT91_SLOW_CLOCK;
+	case AT91_PMC_MCKR_CSS_MAIN:
+		return gd->arch.main_clk_rate_hz;
+	case AT91_PMC_MCKR_CSS_PLLA:
+		return gd->arch.plla_rate_hz;
+	case AT91_PMC_MCKR_CSS_PLLB:
+		return gd->arch.pllb_rate_hz;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_USB_ATMEL
+static unsigned at91_pll_calc(unsigned main_freq, unsigned out_freq)
+{
+	unsigned i, div = 0, mul = 0, diff = 1 << 30;
+	unsigned ret = (out_freq > 155000000) ? 0xbe00 : 0x3e00;
+
+	/* PLL output max 240 MHz (or 180 MHz per errata) */
+	if (out_freq > 240000000)
+		goto fail;
+
+	for (i = 1; i < 256; i++) {
+		int diff1;
+		unsigned input, mul1;
+
+		/*
+		 * PLL input between 1MHz and 32MHz per spec, but lower
+		 * frequences seem necessary in some cases so allow 100K.
+		 * Warning: some newer products need 2MHz min.
+		 */
+		input = main_freq / i;
+#if defined(CONFIG_AT91SAM9G20)
+		if (input < 2000000)
+			continue;
+#endif
+		if (input < 100000)
+			continue;
+		if (input > 32000000)
+			continue;
+
+		mul1 = out_freq / input;
+#if defined(CONFIG_AT91SAM9G20)
+		if (mul > 63)
+			continue;
+#endif
+		if (mul1 > 2048)
+			continue;
+		if (mul1 < 2)
+			goto fail;
+
+		diff1 = out_freq - input * mul1;
+		if (diff1 < 0)
+			diff1 = -diff1;
+		if (diff > diff1) {
+			diff = diff1;
+			div = i;
+			mul = mul1;
+			if (diff == 0)
+				break;
+		}
+	}
+	if (i == 256 && diff > (out_freq >> 5))
+		goto fail;
+	return ret | ((mul - 1) << 16) | div;
+fail:
+	return 0;
+}
+#endif
+
+static u32 at91_pll_rate(u32 freq, u32 reg)
+{
+	unsigned mul, div;
+
+	div = reg & 0xff;
+	mul = (reg >> 16) & 0x7ff;
+	if (div && mul) {
+		freq /= div;
+		freq *= mul + 1;
+	} else
+		freq = 0;
+
+	return freq;
+}
+
+int at91_clock_init(unsigned long main_clock)
+{
+	unsigned freq, mckr;
+	at91_pmc_t *pmc = (at91_pmc_t *) ATMEL_BASE_PMC;
+#ifndef CONFIG_SYS_AT91_MAIN_CLOCK
+	unsigned tmp;
+	/*
+	 * When the bootloader initialized the main oscillator correctly,
+	 * there's no problem using the cycle counter.  But if it didn't,
+	 * or when using oscillator bypass mode, we must be told the speed
+	 * of the main clock.
+	 */
+	if (!main_clock) {
+		do {
+			tmp = readl(&pmc->mcfr);
+		} while (!(tmp & AT91_PMC_MCFR_MAINRDY));
+		tmp &= AT91_PMC_MCFR_MAINF_MASK;
+		main_clock = tmp * (CONFIG_SYS_AT91_SLOW_CLOCK / 16);
+	}
+#endif
+	gd->arch.main_clk_rate_hz = main_clock;
+
+	/* report if PLLA is more than mildly overclocked */
+	gd->arch.plla_rate_hz = at91_pll_rate(main_clock, readl(&pmc->pllar));
+
+#ifdef CONFIG_USB_ATMEL
+	/*
+	 * USB clock init:  choose 48 MHz PLLB value,
+	 * disable 48MHz clock during usb peripheral suspend.
+	 *
+	 * REVISIT:  assumes MCK doesn't derive from PLLB!
+	 */
+	gd->arch.at91_pllb_usb_init = at91_pll_calc(main_clock, 48000000 * 2) |
+			     AT91_PMC_PLLBR_USBDIV_2;
+	gd->arch.pllb_rate_hz = at91_pll_rate(main_clock,
+					      gd->arch.at91_pllb_usb_init);
+#endif
+
+	/*
+	 * MCK and CPU derive from one of those primary clocks.
+	 * For now, assume this parentage won't change.
+	 */
+	mckr = readl(&pmc->mckr);
+#if defined(CONFIG_AT91SAM9G45) || defined(CONFIG_AT91SAM9M10G45) \
+		|| defined(CONFIG_AT91SAM9N12) || defined(CONFIG_AT91SAM9X5)
+	/* plla divisor by 2 */
+	gd->arch.plla_rate_hz /= (1 << ((mckr & 1 << 12) >> 12));
+#endif
+	gd->arch.mck_rate_hz = at91_css_to_rate(mckr & AT91_PMC_MCKR_CSS_MASK);
+	freq = gd->arch.mck_rate_hz;
+
+	freq /= (1 << ((mckr & AT91_PMC_MCKR_PRES_MASK) >> 2));	/* prescale */
+#if defined(CONFIG_AT91SAM9G20)
+	/* mdiv ; (x >> 7) = ((x >> 8) * 2) */
+	gd->arch.mck_rate_hz = (mckr & AT91_PMC_MCKR_MDIV_MASK) ?
+		freq / ((mckr & AT91_PMC_MCKR_MDIV_MASK) >> 7) : freq;
+	if (mckr & AT91_PMC_MCKR_MDIV_MASK)
+		freq /= 2;			/* processor clock division */
+#elif defined(CONFIG_AT91SAM9G45) || defined(CONFIG_AT91SAM9M10G45) \
+		|| defined(CONFIG_AT91SAM9N12) || defined(CONFIG_AT91SAM9X5)
+	/* mdiv <==> divisor
+	 *  0   <==>   1
+	 *  1   <==>   2
+	 *  2   <==>   4
+	 *  3   <==>   3
+	 */
+	gd->arch.mck_rate_hz = (mckr & AT91_PMC_MCKR_MDIV_MASK) ==
+		(AT91_PMC_MCKR_MDIV_2 | AT91_PMC_MCKR_MDIV_4)
+		? freq / 3
+		: freq / (1 << ((mckr & AT91_PMC_MCKR_MDIV_MASK) >> 8));
+#else
+	gd->arch.mck_rate_hz = freq /
+			(1 << ((mckr & AT91_PMC_MCKR_MDIV_MASK) >> 8));
+#endif
+	gd->arch.cpu_clk_rate_hz = freq;
+
+	return 0;
+}
+
+#if !defined(AT91_PLL_LOCK_TIMEOUT)
+#define AT91_PLL_LOCK_TIMEOUT	1000000
+#endif
+
+void at91_plla_init(u32 pllar)
+{
+	struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;
+
+	writel(pllar, &pmc->pllar);
+	while (!(readl(&pmc->sr) & AT91_PMC_LOCKA))
+		;
+}
+void at91_pllb_init(u32 pllbr)
+{
+	struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;
+
+	writel(pllbr, &pmc->pllbr);
+	while (!(readl(&pmc->sr) & AT91_PMC_LOCKB))
+		;
+}
+
+void at91_mck_init(u32 mckr)
+{
+	struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;
+	u32 tmp;
+
+	tmp = readl(&pmc->mckr);
+	tmp &= ~AT91_PMC_MCKR_PRES_MASK;
+	tmp |= mckr & AT91_PMC_MCKR_PRES_MASK;
+	writel(tmp, &pmc->mckr);
+	while (!(readl(&pmc->sr) & AT91_PMC_MCKRDY))
+		;
+
+	tmp = readl(&pmc->mckr);
+	tmp &= ~AT91_PMC_MCKR_MDIV_MASK;
+	tmp |= mckr & AT91_PMC_MCKR_MDIV_MASK;
+	writel(tmp, &pmc->mckr);
+	while (!(readl(&pmc->sr) & AT91_PMC_MCKRDY))
+		;
+
+	tmp = readl(&pmc->mckr);
+	tmp &= ~AT91_PMC_MCKR_PLLADIV_MASK;
+	tmp |= mckr & AT91_PMC_MCKR_PLLADIV_MASK;
+	writel(tmp, &pmc->mckr);
+	while (!(readl(&pmc->sr) & AT91_PMC_MCKRDY))
+		;
+
+	tmp = readl(&pmc->mckr);
+	tmp &= ~AT91_PMC_MCKR_CSS_MASK;
+	tmp |= mckr & AT91_PMC_MCKR_CSS_MASK;
+	writel(tmp, &pmc->mckr);
+	while (!(readl(&pmc->sr) & AT91_PMC_MCKRDY))
+		;
+}
+
+int at91_pllb_clk_enable(u32 pllbr)
+{
+	struct at91_pmc *pmc = (at91_pmc_t *)ATMEL_BASE_PMC;
+	ulong start_time, tmp_time;
+
+	start_time = get_timer(0);
+	writel(pllbr, &pmc->pllbr);
+	while ((readl(&pmc->sr) & AT91_PMC_LOCKB) != AT91_PMC_LOCKB) {
+		tmp_time = get_timer(0);
+		if ((tmp_time - start_time) > EN_PLLB_TIMEOUT) {
+			printf("ERROR: failed to enable PLLB\n");
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+int at91_pllb_clk_disable(void)
+{
+	struct at91_pmc *pmc = (at91_pmc_t *)ATMEL_BASE_PMC;
+	ulong start_time, tmp_time;
+
+	start_time = get_timer(0);
+	writel(0, &pmc->pllbr);
+	while ((readl(&pmc->sr) & AT91_PMC_LOCKB) != 0) {
+		tmp_time = get_timer(0);
+		if ((tmp_time - start_time) > EN_PLLB_TIMEOUT) {
+			printf("ERROR: failed to disable PLLB\n");
+			return -1;
+		}
+	}
+
+	return 0;
+}