irq.c

/*
 * linux/arch/xtensa/kernel/irq.c
 *
 * Xtensa built-in interrupt controller and some generic functions copied
 * from i386.
 *
 * Copyright (C) 2002 - 2006 Tensilica, Inc.
 * Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
 *
 *
 * Chris Zankel <[email protected]>
 * Kevin Chea
 *
 */

#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel_stat.h>

#include <asm/uaccess.h>
#include <asm/platform.h>

static unsigned int cached_irq_mask;

atomic_t irq_err_count;

/*
 * do_IRQ handles all normal device IRQ's (the special
 * SMP cross-CPU interrupts have their own specific
 * handlers).
 */

asmlinkage void do_IRQ(int irq, struct pt_regs *regs)
{
	struct pt_regs *old_regs = set_irq_regs(regs);

	if (irq >= NR_IRQS) {
		printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
				__func__, irq);
	}

	irq_enter();

#ifdef CONFIG_DEBUG_STACKOVERFLOW
	/* Debugging check for stack overflow: is there less than 1KB free? */
	{
		unsigned long sp;

		__asm__ __volatile__ ("mov %0, a1\n" : "=a" (sp));
		sp &= THREAD_SIZE - 1;

		if (unlikely(sp < (sizeof(thread_info) + 1024)))
			printk("Stack overflow in do_IRQ: %ld\n",
			       sp - sizeof(struct thread_info));
	}
#endif
	generic_handle_irq(irq);

	irq_exit();
	set_irq_regs(old_regs);
}

int arch_show_interrupts(struct seq_file *p, int prec)
{
	seq_printf(p, "%*s: ", prec, "ERR");
	seq_printf(p, "%10u\n", atomic_read(&irq_err_count));
	return 0;
}

static void xtensa_irq_mask(struct irq_data *d)
{
	cached_irq_mask &= ~(1 << d->irq);
	set_sr (cached_irq_mask, INTENABLE);
}

static void xtensa_irq_unmask(struct irq_data *d)
{
	cached_irq_mask |= 1 << d->irq;
	set_sr (cached_irq_mask, INTENABLE);
}

static void xtensa_irq_enable(struct irq_data *d)
{
	variant_irq_enable(d->irq);
	xtensa_irq_unmask(d->irq);
}

static void xtensa_irq_disable(struct irq_data *d)
{
	xtensa_irq_mask(d->irq);
	variant_irq_disable(d->irq);
}

static void xtensa_irq_ack(struct irq_data *d)
{
	set_sr(1 << d->irq, INTCLEAR);
}

static int xtensa_irq_retrigger(struct irq_data *d)
{
	set_sr (1 << d->irq, INTSET);
	return 1;
}


static struct irq_chip xtensa_irq_chip = {
	.name		= "xtensa",
	.irq_enable	= xtensa_irq_enable,
	.irq_disable	= xtensa_irq_disable,
	.irq_mask	= xtensa_irq_mask,
	.irq_unmask	= xtensa_irq_unmask,
	.irq_ack	= xtensa_irq_ack,
	.irq_retrigger	= xtensa_irq_retrigger,
};

void __init init_IRQ(void)
{
	int index;

	for (index = 0; index < XTENSA_NR_IRQS; index++) {
		int mask = 1 << index;

		if (mask & XCHAL_INTTYPE_MASK_SOFTWARE)
			irq_set_chip_and_handler(index, &xtensa_irq_chip,
						 handle_simple_irq);

		else if (mask & XCHAL_INTTYPE_MASK_EXTERN_EDGE)
			irq_set_chip_and_handler(index, &xtensa_irq_chip,
						 handle_edge_irq);

		else if (mask & XCHAL_INTTYPE_MASK_EXTERN_LEVEL)
			irq_set_chip_and_handler(index, &xtensa_irq_chip,
						 handle_level_irq);

		else if (mask & XCHAL_INTTYPE_MASK_TIMER)
			irq_set_chip_and_handler(index, &xtensa_irq_chip,
						 handle_edge_irq);

		else	/* XCHAL_INTTYPE_MASK_WRITE_ERROR */
			/* XCHAL_INTTYPE_MASK_NMI */

			irq_set_chip_and_handler(index, &xtensa_irq_chip,
						 handle_level_irq);
	}

	cached_irq_mask = 0;

	variant_init_irq();
}