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/*
* Cirrus Logic EP93xx PLL support.
*
* Copyright (C) 2009 Matthias Kaehlcke <matthias@kaehlcke.net>
*
* See file CREDITS for list of people who contributed to this project.
*
* 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.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <common.h>
#include <asm/arch/ep93xx.h>
#include <asm/io.h>
#include <div64.h>
/*
* 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.
*/
/*
* return the PLL output frequency
*
* PLL rate = CONFIG_SYS_CLK_FREQ * (X1FBD + 1) * (X2FBD + 1)
* / (X2IPD + 1) / 2^PS
*/
static ulong get_PLLCLK(uint32_t *pllreg)
{
uint8_t i;
const uint32_t clkset = readl(pllreg);
uint64_t rate = CONFIG_SYS_CLK_FREQ;
rate *= ((clkset >> SYSCON_CLKSET_PLL_X1FBD1_SHIFT) & 0x1f) + 1;
rate *= ((clkset >> SYSCON_CLKSET_PLL_X2FBD2_SHIFT) & 0x3f) + 1;
do_div(rate, (clkset & 0x1f) + 1); /* X2IPD */
for (i = 0; i < ((clkset >> SYSCON_CLKSET_PLL_PS_SHIFT) & 3); i++)
rate >>= 1;
return (ulong)rate;
}
/* return FCLK frequency */
ulong get_FCLK()
{
const uint8_t fclk_divisors[] = { 1, 2, 4, 8, 16, 1, 1, 1 };
struct syscon_regs *syscon = (struct syscon_regs *)SYSCON_BASE;
const uint32_t clkset1 = readl(&syscon->clkset1);
const uint8_t fclk_div =
fclk_divisors[(clkset1 >> SYSCON_CLKSET1_FCLK_DIV_SHIFT) & 7];
const ulong fclk_rate = get_PLLCLK(&syscon->clkset1) / fclk_div;
return fclk_rate;
}
/* return HCLK frequency */
ulong get_HCLK(void)
{
const uint8_t hclk_divisors[] = { 1, 2, 4, 5, 6, 8, 16, 32 };
struct syscon_regs *syscon = (struct syscon_regs *)SYSCON_BASE;
const uint32_t clkset1 = readl(&syscon->clkset1);
const uint8_t hclk_div =
hclk_divisors[(clkset1 >> SYSCON_CLKSET1_HCLK_DIV_SHIFT) & 7];
const ulong hclk_rate = get_PLLCLK(&syscon->clkset1) / hclk_div;
return hclk_rate;
}
/* return PCLK frequency */
ulong get_PCLK(void)
{
const uint8_t pclk_divisors[] = { 1, 2, 4, 8 };
struct syscon_regs *syscon = (struct syscon_regs *)SYSCON_BASE;
const uint32_t clkset1 = readl(&syscon->clkset1);
const uint8_t pclk_div =
pclk_divisors[(clkset1 >> SYSCON_CLKSET1_PCLK_DIV_SHIFT) & 3];
const ulong pclk_rate = get_HCLK() / pclk_div;
return pclk_rate;
}
/* return UCLK frequency */
ulong get_UCLK(void)
{
struct syscon_regs *syscon = (struct syscon_regs *)SYSCON_BASE;
ulong uclk_rate;
const uint32_t value = readl(&syscon->pwrcnt);
if (value & SYSCON_PWRCNT_UART_BAUD)
uclk_rate = CONFIG_SYS_CLK_FREQ;
else
uclk_rate = CONFIG_SYS_CLK_FREQ / 2;
return uclk_rate;
}
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