/*
 * (C) Copyright 2000-2002
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * (C) Copyright 2004, Psyent Corporation <www.psyent.com>
 * Scott McNutt <smcnutt@psyent.com>
 *
 * 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 <nios2.h>
#include <asm/nios2-io.h>
#include <asm/types.h>
#include <asm/io.h>
#include <asm/ptrace.h>
#include <common.h>
#include <command.h>
#include <watchdog.h>

/****************************************************************************/

struct	irq_action {
	interrupt_handler_t *handler;
	void *arg;
	int count;
};

static struct irq_action vecs[32];

/****************************************************************************/

int disable_interrupts(void)
{
	int val = rdctl(CTL_STATUS);
	wrctl(CTL_STATUS, val & ~STATUS_IE);
	return val & STATUS_IE;
}

void enable_interrupts(void)
{
	int val = rdctl(CTL_STATUS);
	wrctl(CTL_STATUS, val | STATUS_IE);
}

void external_interrupt(struct pt_regs *regs)
{
	unsigned irqs;
	struct irq_action *act;

	/* Evaluate only irqs that are both enabled AND pending */
	irqs = rdctl(CTL_IENABLE) & rdctl(CTL_IPENDING);
	act = vecs;

	/* Assume (as does the Nios2 HAL) that bit 0 is highest
	 * priority. NOTE: There is ALWAYS a handler assigned
	 * (the default if no other).
	 */
	while (irqs) {
		if (irqs & 1) {
			act->handler(act->arg);
			act->count++;
		}
		irqs >>= 1;
		act++;
	}

}

static void def_hdlr(void *arg)
{
	unsigned irqs = rdctl(CTL_IENABLE);

	/* Disable the individual interrupt -- with gratuitous
	 * warning.
	 */
	irqs &= ~(1 << (int)arg);
	wrctl(CTL_IENABLE, irqs);
	printf("WARNING: Disabling unhandled interrupt: %d\n",
			(int)arg);
}

/*************************************************************************/
void irq_install_handler(int irq, interrupt_handler_t *hdlr, void *arg)
{
	int flag;
	struct irq_action *act;
	unsigned ena = rdctl(CTL_IENABLE);

	if ((irq < 0) || (irq > 31))
		return;
	act = &vecs[irq];

	flag = disable_interrupts();
	if (hdlr) {
		act->handler = hdlr;
		act->arg = arg;
		ena |= (1 << irq);		/* enable */
	} else {
		act->handler = def_hdlr;
		act->arg = (void *)irq;
		ena &= ~(1 << irq);		/* disable */
	}
	wrctl(CTL_IENABLE, ena);

	if (flag)
		enable_interrupts();
}


int interrupt_init(void)
{
	int i;

	/* Assign the default handler to all */
	for (i = 0; i < 32; i++) {
		vecs[i].handler = def_hdlr;
		vecs[i].arg = (void *)i;
		vecs[i].count = 0;
	}

	enable_interrupts();
	return 0;
}