74 lines
1.6 KiB
C
74 lines
1.6 KiB
C
/*
|
|
* 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/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;
|
|
}
|
|
}
|