cpu.c

ARM的bootloader代码.rar

/*
 * (C) Copyright 2002
 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
 * Marius Groeger <[e-mail]>
 *
 * (C) Copyright 2002
 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
 * Alex Zuepke <[e-mail]>
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

/*
 * CPU specific code
 */

#include "armboot.h"
#include "command.h"

void cpu_init(bd_t *bd)
{
    /*
     * setup up stack if necessary
     */
#ifdef CONFIG_USE_IRQ
    IRQ_STACK_START = _armboot_end +
      			CONFIG_STACKSIZE + CONFIG_STACKSIZE_IRQ - 4;
    FIQ_STACK_START = IRQ_STACK_START + CONFIG_STACKSIZE_FIQ;
    _armboot_real_end = FIQ_STACK_START + 4;
#else
    _armboot_real_end = _armboot_end + CONFIG_STACKSIZE;
#endif
}

void cleanup_before_linux(bd_t *bd)
{
    /*
     * this function is called just before we call linux
     * it prepares the processor for linux
     *
     * just disable everything that can disturb booting linux
     */

    unsigned long i;

    disable_interrupts();

    /* turn off I-cache */
    asm ("mrc p15, 0, %0, c1, c0, 0": "=r" (i));
    i &= ~0x1000;
    asm ("mcr p15, 0, %0, c1, c0, 0": : "r" (i));

    /* flush I-cache */
    asm ("mcr p15, 0, %0, c7, c5, 0": : "r" (i));
}

void do_reset (cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char *argv[])
{
    extern void reset_cpu(ulong addr);

    printf("reseting ...\n");

    udelay(50000); /* wait 50 ms */
    disable_interrupts();
    reset_cpu(0);
    /*NOTREACHED*/
}

/* taken from blob */
void icache_enable(void)
{
    register u32 i;

    /* read control register */
    asm ("mrc p15, 0, %0, c1, c0, 0": "=r" (i));

    /* set i-cache */
    i |= 0x1000;

    /* write back to control register */
    asm ("mcr p15, 0, %0, c1, c0, 0": : "r" (i));
}

void icache_disable(void)
{
    register u32 i;

    /* read control register */
    asm ("mrc p15, 0, %0, c1, c0, 0": "=r" (i));

    /* clear i-cache */
    i &= ~0x1000;

    /* write back to control register */
    asm ("mcr p15, 0, %0, c1, c0, 0": : "r" (i));

    /* flush i-cache */
    asm ("mcr p15, 0, %0, c7, c5, 0": : "r" (i));
}

int icache_status(void)
{
    register u32 i;

    /* read control register */
    asm ("mrc p15, 0, %0, c1, c0, 0": "=r" (i));

    /* return bit */
    return (i & 0x1000);
}

/* we will never enable dcache, because we have to setup MMU first */
void dcache_enable(void)
{
    return;
}

void dcache_disable(void)
{
    return;
}

int dcache_status(void)
{
    return 0; /* always off */
}