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https://github.com/AsahiLinux/u-boot
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1a4596601f
Signed-off-by: Wolfgang Denk <wd@denx.de> [trini: Fixup common/cmd_io.c] Signed-off-by: Tom Rini <trini@ti.com>
122 lines
2.7 KiB
C
122 lines
2.7 KiB
C
/*
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* [origin: Linux kernel linux/arch/arm/mach-at91/clock.c]
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*
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* Copyright (C) 2005 David Brownell
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* Copyright (C) 2005 Ivan Kokshaysky
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* Copyright (C) 2009 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
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* Copyright (C) 2013 Bo Shen <voice.shen@atmel.com>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <asm/io.h>
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#include <asm/arch/hardware.h>
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#include <asm/arch/at91_pmc.h>
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#include <asm/arch/clk.h>
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#if !defined(CONFIG_AT91FAMILY)
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# error You need to define CONFIG_AT91FAMILY in your board config!
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#endif
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DECLARE_GLOBAL_DATA_PTR;
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static unsigned long at91_css_to_rate(unsigned long css)
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{
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switch (css) {
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case AT91_PMC_MCKR_CSS_SLOW:
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return CONFIG_SYS_AT91_SLOW_CLOCK;
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case AT91_PMC_MCKR_CSS_MAIN:
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return gd->arch.main_clk_rate_hz;
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case AT91_PMC_MCKR_CSS_PLLA:
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return gd->arch.plla_rate_hz;
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}
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return 0;
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}
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static u32 at91_pll_rate(u32 freq, u32 reg)
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{
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unsigned mul, div;
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div = reg & 0xff;
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mul = (reg >> 18) & 0x7f;
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if (div && mul) {
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freq /= div;
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freq *= mul + 1;
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} else {
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freq = 0;
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}
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return freq;
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}
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int at91_clock_init(unsigned long main_clock)
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{
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unsigned freq, mckr;
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struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;
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#ifndef CONFIG_SYS_AT91_MAIN_CLOCK
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unsigned tmp;
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/*
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* When the bootloader initialized the main oscillator correctly,
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* there's no problem using the cycle counter. But if it didn't,
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* or when using oscillator bypass mode, we must be told the speed
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* of the main clock.
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*/
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if (!main_clock) {
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do {
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tmp = readl(&pmc->mcfr);
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} while (!(tmp & AT91_PMC_MCFR_MAINRDY));
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tmp &= AT91_PMC_MCFR_MAINF_MASK;
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main_clock = tmp * (CONFIG_SYS_AT91_SLOW_CLOCK / 16);
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}
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#endif
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gd->arch.main_clk_rate_hz = main_clock;
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/* report if PLLA is more than mildly overclocked */
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gd->arch.plla_rate_hz = at91_pll_rate(main_clock, readl(&pmc->pllar));
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/*
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* MCK and CPU derive from one of those primary clocks.
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* For now, assume this parentage won't change.
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*/
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mckr = readl(&pmc->mckr);
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/* plla divisor by 2 */
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if (mckr & (1 << 12))
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gd->arch.plla_rate_hz >>= 1;
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gd->arch.mck_rate_hz = at91_css_to_rate(mckr & AT91_PMC_MCKR_CSS_MASK);
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freq = gd->arch.mck_rate_hz;
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/* prescale */
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freq >>= mckr & AT91_PMC_MCKR_PRES_MASK;
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switch (mckr & AT91_PMC_MCKR_MDIV_MASK) {
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case AT91_PMC_MCKR_MDIV_2:
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gd->arch.mck_rate_hz = freq / 2;
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break;
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case AT91_PMC_MCKR_MDIV_3:
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gd->arch.mck_rate_hz = freq / 3;
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break;
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case AT91_PMC_MCKR_MDIV_4:
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gd->arch.mck_rate_hz = freq / 4;
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break;
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default:
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break;
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}
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gd->arch.cpu_clk_rate_hz = freq;
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return 0;
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}
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void at91_periph_clk_enable(int id)
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{
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struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;
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if (id > 31)
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writel(1 << (id - 32), &pmc->pcer1);
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else
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writel(1 << id, &pmc->pcer);
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}
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