u-boot/cpu/arm926ejs/cpu.c

/*
 * (C) Copyright 2002
 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
 * Marius Groeger <mgroeger@sysgo.de>
 *
 * (C) Copyright 2002
 * Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
 *
 * 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 <common.h>
#include <command.h>
#include <arm926ejs.h>
#include <asm/system.h>

#ifdef CONFIG_USE_IRQ
DECLARE_GLOBAL_DATA_PTR;
#endif

static void cp_delay (void)
{
	volatile int i;

	/* copro seems to need some delay between reading and writing */
	for (i = 0; i < 100; i++);
}

int cpu_init (void)
{
	/*
	 * setup up stacks if necessary
	 */
#ifdef CONFIG_USE_IRQ
	IRQ_STACK_START = _armboot_start - CONFIG_SYS_MALLOC_LEN - CONFIG_SYS_GBL_DATA_SIZE - 4;
	FIQ_STACK_START = IRQ_STACK_START - CONFIG_STACKSIZE_IRQ;
#endif
	return 0;
}

int cleanup_before_linux (void)
{
	/*
	 * this function is called just before we call linux
	 * it prepares the processor for linux
	 *
	 * we turn off caches etc ...
	 */

	unsigned long i;

	disable_interrupts ();

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

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

	return (0);
}

int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
{
	disable_interrupts ();
	reset_cpu (0);
	/*NOTREACHED*/
	return (0);
}

/* cache_bit must be either CR_I or CR_C */
static void cache_enable(uint32_t cache_bit)
{
	uint32_t reg;

	reg = get_cr();	/* get control reg. */
	cp_delay();
	set_cr(reg | cache_bit);
}

/* cache_bit must be either CR_I or CR_C */
static void cache_disable(uint32_t cache_bit)
{
	uint32_t reg;

	reg = get_cr();
	cp_delay();
	set_cr(reg & ~cache_bit);
}

void icache_enable(void)
{
	cache_enable(CR_I);
}

void icache_disable(void)
{
	cache_disable(CR_I);
}

int icache_status(void)
{
	return (get_cr() & CR_I) != 0;
}

void dcache_enable(void)
{
	cache_enable(CR_C);
}

void dcache_disable(void)
{
	cache_disable(CR_C);
}

int dcache_status(void)
{
	return (get_cr() & CR_C) != 0;
}