Logo Search packages:      
Sourcecode: linux version File versions  Download package

ibm440gp_common.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;
      }
}

Generated by  Doxygen 1.6.0   Back to index