env.c

Go to the documentation of this file.

/*
 * Based on Ocelot Linux port, which is
 * Copyright 2001 MontaVista Software Inc.
 * Author: [email protected] or [email protected]
 *
 * Copyright 2003 ICT CAS
 * Author: Michael Guo <[email protected]>
 *
 * Copyright (C) 2007 Lemote Inc. & Insititute of Computing Technology
 * Author: Fuxin Zhang, [email protected]
 *
 * Copyright (C) 2009 Lemote Inc.
 * Author: Wu Zhangjin, [email protected]
 *
 * 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/module.h>

#include <asm/bootinfo.h>

#include <loongson.h>

unsigned long cpu_clock_freq;
EXPORT_SYMBOL(cpu_clock_freq);
unsigned long memsize, highmemsize;

#define parse_even_earlier(res, option, p)              \
do {                                    \
    unsigned int tmp __maybe_unused;                \
                                    \
    if (strncmp(option, (char *)p, strlen(option)) == 0)        \
        tmp = strict_strtol((char *)p + strlen(option"="), 10, &res); \
} while (0)

void __init prom_init_env(void)
{
    /* pmon passes arguments in 32bit pointers */
    int *_prom_envp;
    unsigned long bus_clock;
    unsigned int processor_id;
    long l;

    /* firmware arguments are initialized in head.S */
    _prom_envp = (int *)fw_arg2;

    l = (long)*_prom_envp;
    while (l != 0) {
        parse_even_earlier(bus_clock, "busclock", l);
        parse_even_earlier(cpu_clock_freq, "cpuclock", l);
        parse_even_earlier(memsize, "memsize", l);
        parse_even_earlier(highmemsize, "highmemsize", l);
        _prom_envp++;
        l = (long)*_prom_envp;
    }
    if (memsize == 0)
        memsize = 256;
    if (bus_clock == 0)
        bus_clock = 66000000;
    if (cpu_clock_freq == 0) {
        processor_id = (&current_cpu_data)->processor_id;
        switch (processor_id & PRID_REV_MASK) {
        case PRID_REV_LOONGSON2E:
            cpu_clock_freq = 533080000;
            break;
        case PRID_REV_LOONGSON2F:
            cpu_clock_freq = 797000000;
            break;
        default:
            cpu_clock_freq = 100000000;
            break;
        }
    }

    pr_info("busclock=%ld, cpuclock=%ld, memsize=%ld, highmemsize=%ld\n",
        bus_clock, cpu_clock_freq, memsize, highmemsize);
}