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

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * MPC8xx support functions
   4 *
   5 * Author: Scott Wood <scottwood@freescale.com>
   6 *
   7 * Copyright (c) 2007 Freescale Semiconductor, Inc.
   8 */
   9
  10#include "ops.h"
  11#include "types.h"
  12#include "fsl-soc.h"
  13#include "mpc8xx.h"
  14#include "stdio.h"
  15#include "io.h"
  16
  17#define MPC8XX_PLPRCR (0x284/4) /* PLL and Reset Control Register */
  18
  19/* Return system clock from crystal frequency */
  20u32 mpc885_get_clock(u32 crystal)
  21{
  22        u32 *immr;
  23        u32 plprcr;
  24        int mfi, mfn, mfd, pdf;
  25        u32 ret;
  26
  27        immr = fsl_get_immr();
  28        if (!immr) {
  29                printf("mpc885_get_clock: Couldn't get IMMR base.\r\n");
  30                return 0;
  31        }
  32
  33        plprcr = in_be32(&immr[MPC8XX_PLPRCR]);
  34
  35        mfi = (plprcr >> 16) & 15;
  36        if (mfi < 5) {
  37                printf("Warning: PLPRCR[MFI] value of %d out-of-bounds\r\n",
  38                       mfi);
  39                mfi = 5;
  40        }
  41
  42        pdf = (plprcr >> 1) & 0xf;
  43        mfd = (plprcr >> 22) & 0x1f;
  44        mfn = (plprcr >> 27) & 0x1f;
  45
  46        ret = crystal * mfi;
  47
  48        if (mfn != 0)
  49                ret += crystal * mfn / (mfd + 1);
  50
  51        return ret / (pdf + 1);
  52}
  53
  54/* Set common device tree fields based on the given clock frequencies. */
  55void mpc8xx_set_clocks(u32 sysclk)
  56{
  57        void *node;
  58
  59        dt_fixup_cpu_clocks(sysclk, sysclk / 16, sysclk);
  60
  61        node = finddevice("/soc/cpm");
  62        if (node)
  63                setprop(node, "clock-frequency", &sysclk, 4);
  64
  65        node = finddevice("/soc/cpm/brg");
  66        if (node)
  67                setprop(node, "clock-frequency", &sysclk, 4);
  68}
  69
  70int mpc885_fixup_clocks(u32 crystal)
  71{
  72        u32 sysclk = mpc885_get_clock(crystal);
  73        if (!sysclk)
  74                return 0;
  75
  76        mpc8xx_set_clocks(sysclk);
  77        return 1;
  78}
  79