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/*
* PPC440GP system library
*
* Matt Porter <mporter@mvista.com>
* Copyright 2002-2003 MontaVista Software Inc.
*
* Eugene Surovegin <eugene.surovegin@zultys.com> or <ebs@ebshome.net>
* Copyright (c) 2003 Zultys Technologies
*
* 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 <linux/config.h>
#include <linux/types.h>
#include <asm/reg.h>
#include <asm/ibm44x.h>
#include <asm/mmu.h>
/*
* Calculate 440GP clocks
*/
void __init ibm440gp_get_clocks(struct ibm44x_clocks* p,
unsigned int sys_clk,
unsigned int ser_clk)
{
u32 cpc0_sys0 = mfdcr(DCRN_CPC0_SYS0);
u32 cpc0_cr0 = mfdcr(DCRN_CPC0_CR0);
u32 opdv = ((cpc0_sys0 >> 10) & 0x3) + 1;
u32 epdv = ((cpc0_sys0 >> 8) & 0x3) + 1;
if (cpc0_sys0 & 0x2){
/* Bypass system PLL */
p->cpu = p->plb = sys_clk;
}
else {
u32 fbdv, fwdva, fwdvb, m, vco;
fbdv = (cpc0_sys0 >> 18) & 0x0f;
if (!fbdv)
fbdv = 16;
fwdva = 8 - ((cpc0_sys0 >> 15) & 0x7);
fwdvb = 8 - ((cpc0_sys0 >> 12) & 0x7);
/* Feedback path */
if (cpc0_sys0 & 0x00000080){
/* PerClk */
m = fwdvb * opdv * epdv;
}
else {
/* CPU clock */
m = fbdv * fwdva;
}
vco = sys_clk * m;
p->cpu = vco / fwdva;
p->plb = vco / fwdvb;
}
p->opb = p->plb / opdv;
p->ebc = p->opb / epdv;
if (cpc0_cr0 & 0x00400000){
/* External UART clock */
p->uart0 = p->uart1 = ser_clk;
}
else {
/* Internal UART clock */
u32 uart_div = ((cpc0_cr0 >> 16) & 0x1f) + 1;
p->uart0 = p->uart1 = p->plb / uart_div;
}
}
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