interrupts.c

uboot详细解读可用启动引导LINUX2.6内核

/*
 * (C) Copyright 2000-2002
 * Wolfgang Denk, DENX Software Engineering, [e-mail].
 *
 * (C) Copyright 2003
 * Gleb Natapov <[e-mail]>
 *
 * (C) Copyright 2007
 * Daniel Hellstrom, Gaisler Research, [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
 */

#include <common.h>
#include <asm/processor.h>
#include <asm/irq.h>

/* Implemented by SPARC CPUs */
extern int interrupt_init_cpu(void);
extern void timer_interrupt_cpu(void *arg);
extern int timer_interrupt_init_cpu(void);

int intLock(void)
{
	unsigned int pil;

	pil = get_pil();

	/* set PIL to 15 ==> no pending interrupts will interrupt CPU */
	set_pil(15);

	return pil;
}

void intUnlock(int oldLevel)
{
	set_pil(oldLevel);
}

void enable_interrupts(void)
{
	set_pil(0);		/* enable all interrupts */
}

int disable_interrupts(void)
{
	return intLock();
}

int interrupt_init(void)
{
	int ret;

	/* call cpu specific function from $(CPU)/interrupts.c */
	ret = interrupt_init_cpu();

	/* enable global interrupts */
	enable_interrupts();

	return ret;
}

/* timer interrupt/overflow counter */
static volatile ulong timestamp = 0;

/* regs can not be used here! regs is actually the pointer given in
 * irq_install_handler
 */
void timer_interrupt(struct pt_regs *regs)
{
	/* call cpu specific function from $(CPU)/interrupts.c */
	timer_interrupt_cpu((void *)regs);

	timestamp++;
}

void reset_timer(void)
{
	timestamp = 0;
}

ulong get_timer(ulong base)
{
	return (timestamp - base);
}

void set_timer(ulong t)
{
	timestamp = t;
}

void timer_interrupt_init(void)
{
	int irq;

	reset_timer();

	irq = timer_interrupt_init_cpu();

	if (irq < 0) {
		/* cpu specific code handled the interrupt registration it self */
		return;
	}
	/* register interrupt handler for timer */
	irq_install_handler(irq, (void (*)(void *))timer_interrupt, NULL);
}