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