LXR linux/arch/powerpc/boot/mpc8xx.c

   1/*
   2 * MPC8xx support functions
   3 *
   4 * Author: Scott Wood <scottwood@freescale.com>
   5 *
   6 * Copyright (c) 2007 Freescale Semiconductor, Inc.
   7 *
   8 * This program is free software; you can redistribute it and/or modify it
   9 * under the terms of the GNU General Public License version 2 as published
  10 * by the Free Software Foundation.
  11 */
  12
  13#include "ops.h"
  14#include "types.h"
  15#include "fsl-soc.h"
  16#include "mpc8xx.h"
  17#include "stdio.h"
  18#include "io.h"
  19
  20#define MPC8XX_PLPRCR (0x284/4) /* PLL and Reset Control Register */
  21
  22/* Return system clock from crystal frequency */
  23u32 mpc885_get_clock(u32 crystal)
  24{
  25        u32 *immr;
  26        u32 plprcr;
  27        int mfi, mfn, mfd, pdf, div;
  28        u32 ret;
  29
  30        immr = fsl_get_immr();
  31        if (!immr) {
  32                printf("mpc885_get_clock: Couldn't get IMMR base.\r\n");
  33                return 0;
  34        }
  35
  36        plprcr = in_be32(&immr[MPC8XX_PLPRCR]);
  37
  38        mfi = (plprcr >> 16) & 15;
  39        if (mfi < 5) {
  40                printf("Warning: PLPRCR[MFI] value of %d out-of-bounds\r\n",
  41                       mfi);
  42                mfi = 5;
  43        }
  44
  45        pdf = (plprcr >> 1) & 0xf;
  46        div = (plprcr >> 20) & 3;
  47        mfd = (plprcr >> 22) & 0x1f;
  48        mfn = (plprcr >> 27) & 0x1f;
  49
  50        ret = crystal * mfi;
  51
  52        if (mfn != 0)
  53                ret += crystal * mfn / (mfd + 1);
  54
  55        return ret / (pdf + 1);
  56}
  57
  58/* Set common device tree fields based on the given clock frequencies. */
  59void mpc8xx_set_clocks(u32 sysclk)
  60{
  61        void *node;
  62
  63        dt_fixup_cpu_clocks(sysclk, sysclk / 16, sysclk);
  64
  65        node = finddevice("/soc/cpm");
  66        if (node)
  67                setprop(node, "clock-frequency", &sysclk, 4);
  68
  69        node = finddevice("/soc/cpm/brg");
  70        if (node)
  71                setprop(node, "clock-frequency", &sysclk, 4);
  72}
  73
  74int mpc885_fixup_clocks(u32 crystal)
  75{
  76        u32 sysclk = mpc885_get_clock(crystal);
  77        if (!sysclk)
  78                return 0;
  79
  80        mpc8xx_set_clocks(sysclk);
  81        return 1;
  82}
  83