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/*
* [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>
* Copyright (C) 2013 Bo Shen <voice.shen@atmel.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#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
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;
}
return 0;
}
static u32 at91_pll_rate(u32 freq, u32 reg)
{
unsigned mul, div;
div = reg & 0xff;
mul = (reg >> 18) & 0x7f;
if (div && mul) {
freq /= div;
freq *= mul + 1;
} else {
freq = 0;
}
return freq;
}
int at91_clock_init(unsigned long main_clock)
{
unsigned freq, mckr;
struct at91_pmc *pmc = (struct at91_pmc *)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));
/*
* MCK and CPU derive from one of those primary clocks.
* For now, assume this parentage won't change.
*/
mckr = readl(&pmc->mckr);
/* plla divisor by 2 */
if (mckr & (1 << 12))
gd->arch.plla_rate_hz >>= 1;
gd->arch.mck_rate_hz = at91_css_to_rate(mckr & AT91_PMC_MCKR_CSS_MASK);
freq = gd->arch.mck_rate_hz;
/* prescale */
freq >>= mckr & AT91_PMC_MCKR_PRES_MASK;
switch (mckr & AT91_PMC_MCKR_MDIV_MASK) {
case AT91_PMC_MCKR_MDIV_2:
gd->arch.mck_rate_hz = freq / 2;
break;
case AT91_PMC_MCKR_MDIV_3:
gd->arch.mck_rate_hz = freq / 3;
break;
case AT91_PMC_MCKR_MDIV_4:
gd->arch.mck_rate_hz = freq / 4;
break;
default:
break;
}
gd->arch.cpu_clk_rate_hz = freq;
return 0;
}
void at91_periph_clk_enable(int id)
{
struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;
if (id > 31)
writel(1 << (id - 32), &pmc->pcer1);
else
writel(1 << id, &pmc->pcer);
}
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