arch/mips/loongson/common/env.c

   1 /*
   2  * Based on Ocelot Linux port, which is
   3  * Copyright 2001 MontaVista Software Inc.
   4  * Author: jsun@mvista.com or jsun@junsun.net
   5  *
   6  * Copyright 2003 ICT CAS
   7  * Author: Michael Guo <guoyi@ict.ac.cn>
   8  *
   9  * Copyright (C) 2007 Lemote Inc. & Insititute of Computing Technology
  10  * Author: Fuxin Zhang, zhangfx@lemote.com
  11  *
  12  * Copyright (C) 2009 Lemote Inc.
  13  * Author: Wu Zhangjin, wuzhangjin@gmail.com
  14  *
  15  * This program is free software; you can redistribute  it and/or modify it
  16  * under  the terms of  the GNU General  Public License as published by the
  17  * Free Software Foundation;  either version 2 of the  License, or (at your
  18  * option) any later version.
  19  */
  20 #include <linux/module.h>
  21
  22 #include <asm/bootinfo.h>
  23
  24 #include <loongson.h>
  25
  26 unsigned long cpu_clock_freq;
  27 EXPORT_SYMBOL(cpu_clock_freq);
  28 unsigned long memsize, highmemsize;
  29
  30 #define parse_even_earlier(res, option, p)                              \
  31 do {                                                                    \
  32         unsigned int tmp __maybe_unused;                                \
  33                                                                         \
  34         if (strncmp(option, (char *)p, strlen(option)) == 0)            \
  35                 tmp = strict_strtol((char *)p + strlen(option"="), 10, &res); \
  36 } while (0)
  37
  38 void __init prom_init_env(void)
  39 {
  40         /* pmon passes arguments in 32bit pointers */
  41         int *_prom_envp;
  42         unsigned long bus_clock;
  43         unsigned int processor_id;
  44         long l;
  45
  46         /* firmware arguments are initialized in head.S */
  47         _prom_envp = (int *)fw_arg2;
  48
  49         l = (long)*_prom_envp;
  50         while (l != 0) {
  51                 parse_even_earlier(bus_clock, "busclock", l);
  52                 parse_even_earlier(cpu_clock_freq, "cpuclock", l);
  53                 parse_even_earlier(memsize, "memsize", l);
  54                 parse_even_earlier(highmemsize, "highmemsize", l);
  55                 _prom_envp++;
  56                 l = (long)*_prom_envp;
  57         }
  58         if (memsize == 0)
  59                 memsize = 256;
  60         if (bus_clock == 0)
  61                 bus_clock = 66000000;
  62         if (cpu_clock_freq == 0) {
  63                 processor_id = (&current_cpu_data)->processor_id;
  64                 switch (processor_id & PRID_REV_MASK) {
  65                 case PRID_REV_LOONGSON2E:
  66                         cpu_clock_freq = 533080000;
  67                         break;
  68                 case PRID_REV_LOONGSON2F:
  69                         cpu_clock_freq = 797000000;
  70                         break;
  71                 default:
  72                         cpu_clock_freq = 100000000;
  73                         break;
  74                 }
  75         }
  76
  77         pr_info("busclock=%ld, cpuclock=%ld, memsize=%ld, highmemsize=%ld\n",
  78                 bus_clock, cpu_clock_freq, memsize, highmemsize);
  79 }