/*
 *  linux/arch/mips/philips/nino/irq.c
 *
 *  Copyright (C) 1992 Linus Torvalds
 *  Copyright (C) 1999 Harald Koerfgen
 *  Copyright (C) 2000 Pavel Machek (pavel@suse.cz)
 *  Copyright (C) 2001 Steven J. Hill (sjhill@realitydiluted.com)
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *  
 *  Generic interrupt handler for Philips Nino.
 */
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/timex.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/seq_file.h>

#include <asm/bitops.h>
#include <asm/bootinfo.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/mipsregs.h>
#include <asm/system.h>
#include <asm/tx3912.h>

unsigned long spurious_count = 0;

irq_cpustat_t irq_stat [NR_CPUS];

static inline void mask_irq(unsigned int irq_nr)
{
	switch (irq_nr) {
	case 0:  /* Periodic Timer Interrupt */ 
		IntClear5 = INT5_PERIODICINT;
		IntClear6 = INT6_PERIODICINT;
		IntEnable6 &= ~INT6_PERIODICINT;
		break;

	case 3:
		/* Serial port receive interrupt */
		break;

	case 2:
		/* Serial port transmit interrupt */
		break;

	default:
		printk( "Attempt to mask unknown IRQ %d?\n", irq_nr );
	}
}

static inline void unmask_irq(unsigned int irq_nr)
{
	switch (irq_nr) {
	case 0:
		IntEnable6 |= INT6_PERIODICINT;
		break;

	case 3:
		/* Serial port receive interrupt */
		break;

	case 2:
		/* Serial port transmit interrupt */
		break;

	default:
		printk( "Attempt to unmask unknown IRQ %d?\n", irq_nr );
	}
}

void disable_irq(unsigned int irq_nr)
{
    unsigned long flags;

    save_and_cli(flags);
    mask_irq(irq_nr);
    restore_flags(flags);
}

void enable_irq(unsigned int irq_nr)
{
    unsigned long flags;

    save_and_cli(flags);
    unmask_irq(irq_nr);
    restore_flags(flags);
}

/*
 * Pointers to the low-level handlers: first the general ones, then the
 * fast ones, then the bad ones.
 */
extern void interrupt(void);

static struct irqaction *irq_action[NR_IRQS] =
{
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
};

int show_interrupts(struct seq_file *p, void *v)
{
    int i;
    struct irqaction *action;
    unsigned long flags;

    for (i = 0; i < NR_IRQS; i++) {
	local_irq_save(flags);
	action = irq_action[i];
	if (!action)
	    goto skip;
	seq_printf(p, "%2d: %8d %c %s",
		       i, kstat_cpu(0).irqs[i],
		       (action->flags & SA_INTERRUPT) ? '+' : ' ',
		       action->name);
	for (action = action->next; action; action = action->next) {
	    seq_printf(p, ",%s %s",
			   (action->flags & SA_INTERRUPT) ? " +" : "",
			   action->name);
	}
	seq_putc(p, '\n');
skip:
	local_irq_restore(flags);
    }
    return 0;
}

atomic_t __mips_bh_counter;

/*
 * do_IRQ handles IRQ's that have been installed without the
 * SA_INTERRUPT flag: it uses the full signal-handling return
 * and runs with other interrupts enabled. All relatively slow
 * IRQ's should use this format: notably the keyboard/timer
 * routines.
 */
asmlinkage void do_IRQ(int irq, struct pt_regs *regs)
{
    struct irqaction *action;
    int do_random, cpu;

    if (irq == 20) {
        if (IntStatus2 & 0xfffff00) {
		if (IntStatus2 & 0x0f000000)
		return do_IRQ(2, regs);
	}
    }

    cpu = smp_processor_id();
    irq_enter(cpu, irq);
    kstat_cpu(0).irqs[irq]++;

    if (irq == 20) {
            printk("20 %08lx %08lx\n   %08lx %08lx\n   %08lx\n",
                   IntStatus1, IntStatus2, IntStatus3,
                   IntStatus4, IntStatus5 );
            printk("20 %08lx %08lx\n   %08lx %08lx\n   %08lx\n",
                   IntEnable1, IntEnable2, IntEnable3,
                   IntEnable4, IntEnable5 );

    }

    mask_irq(irq);
    action = *(irq + irq_action);
    if (action) {
	if (!(action->flags & SA_INTERRUPT))
	    local_irq_enable();
	do_random = 0;
	do {
	    do_random |= action->flags;
	    action->handler(irq, action->dev_id, regs);
	    action = action->next;
	} while (action);
	if (do_random & SA_SAMPLE_RANDOM)
	    add_interrupt_randomness(irq);
	unmask_irq(irq);
	local_irq_disable();
    } else {
            IntClear1 = ~0;
            IntClear3 = ~0;
	    IntClear4 = ~0;
	    IntClear5 = ~0;
	    unmask_irq(irq);
    }
    irq_exit(cpu, irq);

    /* unmasking and bottom half handling is done magically for us. */
}

/*
 * Idea is to put all interrupts
 * in a single table and differenciate them just by number.
 */
int setup_nino_irq(int irq, struct irqaction *new)
{
    int shared = 0;
    struct irqaction *old, **p;
    unsigned long flags;

    p = irq_action + irq;
    if ((old = *p) != NULL) {
	/* Can't share interrupts unless both agree to */
	if (!(old->flags & new->flags & SA_SHIRQ))
	    return -EBUSY;

	/* Can't share interrupts unless both are same type */
	if ((old->flags ^ new->flags) & SA_INTERRUPT)
	    return -EBUSY;

	/* add new interrupt at end of irq queue */
	do {
	    p = &old->next;
	    old = *p;
	} while (old);
	shared = 1;
    }
    if (new->flags & SA_SAMPLE_RANDOM)
	rand_initialize_irq(irq);

    save_and_cli(flags);
    *p = new;

    if (!shared) {
	unmask_irq(irq);
    }
    restore_flags(flags);
    return 0;
}

int request_irq(unsigned int irq,
		void (*handler) (int, void *, struct pt_regs *),
		unsigned long irqflags,
		const char *devname,
		void *dev_id)
{
    int retval;
    struct irqaction *action;

    if (irq >= NR_IRQS)
	return -EINVAL;
    if (!handler)
	return -EINVAL;

    action = (struct irqaction *) kmalloc(sizeof(struct irqaction), GFP_KERNEL);
    if (!action)
	return -ENOMEM;

    action->handler = handler;
    action->flags = irqflags;
    action->mask = 0;
    action->name = devname;
    action->next = NULL;
    action->dev_id = dev_id;

    retval = setup_nino_irq(irq, action);

    if (retval)
	kfree(action);
    return retval;
}

void free_irq(unsigned int irq, void *dev_id)
{
    struct irqaction *action, **p;
    unsigned long flags;

    if (irq >= NR_IRQS) {
	printk(KERN_CRIT __FUNCTION__ ": trying to free IRQ%d\n", irq);
	return;
    }
    for (p = irq + irq_action; (action = *p) != NULL; p = &action->next) {
	if (action->dev_id != dev_id)
	    continue;

	/* Found it - now free it */
	save_and_cli(flags);
	*p = action->next;
	if (!irq[irq_action])
	    mask_irq(irq);
	restore_flags(flags);
	kfree(action);
	return;
    }
    printk(KERN_CRIT __FUNCTION__ ": trying to free free IRQ%d\n", irq);
}

unsigned long probe_irq_on(void)
{
    /* TODO */
    return 0;
}

int probe_irq_off(unsigned long irqs)
{
    /* TODO */
    return 0;
}

void __init init_IRQ(void)
{
    irq_setup();
}
