u-boot/arch/mips/cpu/mips32/incaip/incaip_clock.c

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/*
* (C) Copyright 2003
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*
* 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., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#include <asm/inca-ip.h>
/*******************************************************************************
*
* get_cpuclk - returns the frequency of the CPU.
*
* Gets the value directly from the INCA-IP hardware.
*
* RETURNS:
* 150.000.000 for 150 MHz
* 133.333.333 for 133 MHz (= 400MHz/3)
* 100.000.000 for 100 MHz (= 400MHz/4)
* NOTE:
* This functions should be used by the hardware driver to get the correct
* frequency of the CPU. Don't use the macros, which are set to init the CPU
* frequency in the ROM code.
*/
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uint incaip_get_cpuclk (void)
{
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/*-------------------------------------------------------------------------*/
/* CPU Clock Input Multiplexer (MUX I) */
/* Multiplexer MUX I selects the maximum input clock to the CPU. */
/*-------------------------------------------------------------------------*/
if (*((volatile ulong *) INCA_IP_CGU_CGU_MUXCR) &
INCA_IP_CGU_CGU_MUXCR_MUXI) {
/* MUX I set to 150 MHz clock */
return 150000000;
} else {
/* MUX I set to 100/133 MHz clock */
if (*((volatile ulong *) INCA_IP_CGU_CGU_DIVCR) & 0x40) {
/* Division value is 1/3, maximum CPU operating */
/* frequency is 133.3 MHz */
return 133333333;
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} else {
/* Division value is 1/4, maximum CPU operating */
/* frequency is 100 MHz */
return 100000000;
}
}
}
/*******************************************************************************
*
* get_fpiclk - returns the frequency of the FPI bus.
*
* Gets the value directly from the INCA-IP hardware.
*
* RETURNS: Frquency in Hz
*
* NOTE:
* This functions should be used by the hardware driver to get the correct
* frequency of the CPU. Don't use the macros, which are set to init the CPU
* frequency in the ROM code.
* The calculation for the
*/
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uint incaip_get_fpiclk (void)
{
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uint clkCPU;
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clkCPU = incaip_get_cpuclk ();
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switch (*((volatile ulong *) INCA_IP_CGU_CGU_DIVCR) & 0xC) {
case 0x4:
return clkCPU >> 1; /* devided by 2 */
break;
case 0x8:
return clkCPU >> 2; /* devided by 4 */
break;
default:
return clkCPU;
break;
}
}
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int incaip_set_cpuclk (void)
{
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extern void ebu_init(long);
extern void cgu_init(long);
extern void sdram_init(long);
char tmp[64];
ulong cpuclk;
if (getenv_f("cpuclk", tmp, sizeof (tmp)) > 0) {
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cpuclk = simple_strtoul (tmp, NULL, 10) * 1000000;
cgu_init (cpuclk);
ebu_init (cpuclk);
sdram_init (cpuclk);
}
return 0;
}