irq.c

来自「优龙2410linux2.6.8内核源代码」· C语言 代码 · 共 1,017 行 · 第 1/2 页

/*
 *  arch/ppc/kernel/irq.c
 *
 *  Derived from arch/i386/kernel/irq.c
 *    Copyright (C) 1992 Linus Torvalds
 *  Adapted from arch/i386 by Gary Thomas
 *    Copyright (C) 1995-1996 Gary Thomas ([e-mail])
 *  Updated and modified by Cort Dougan ([e-mail])
 *    Copyright (C) 1996 Cort Dougan
 *  Adapted for Power Macintosh by Paul Mackerras
 *    Copyright (C) 1996 Paul Mackerras ([e-mail])
 *  Amiga/APUS changes by Jesper Skov ([e-mail]).
 * 
 * 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 file contains the code used by various IRQ handling routines:
 * asking for different IRQ's should be done through these routines
 * instead of just grabbing them. Thus setups with different IRQ numbers
 * shouldn't result in any weird surprises, and installing new handlers
 * should be easier.
 */

#include <linux/errno.h>
#include <linux/module.h>
#include <linux/threads.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/timex.h>
#include <linux/config.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/proc_fs.h>
#include <linux/random.h>
#include <linux/kallsyms.h>

#include <asm/uaccess.h>
#include <asm/bitops.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/irq.h>
#include <asm/cache.h>
#include <asm/prom.h>
#include <asm/ptrace.h>
#include <asm/iSeries/LparData.h>
#include <asm/machdep.h>
#include <asm/paca.h>

#ifdef CONFIG_SMP
extern void iSeries_smp_message_recv( struct pt_regs * );
#endif

static void register_irq_proc (unsigned int irq);

irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {
	[0 ... NR_IRQS-1] = {
		.lock = SPIN_LOCK_UNLOCKED
	}
};

int __irq_offset_value;
int ppc_spurious_interrupts;
unsigned long lpevent_count;

int
setup_irq(unsigned int irq, struct irqaction * new)
{
	int shared = 0;
	unsigned long flags;
	struct irqaction *old, **p;
	irq_desc_t *desc = get_irq_desc(irq);

	/*
	 * Some drivers like serial.c use request_irq() heavily,
	 * so we have to be careful not to interfere with a
	 * running system.
	 */
	if (new->flags & SA_SAMPLE_RANDOM) {
		/*
		 * This function might sleep, we want to call it first,
		 * outside of the atomic block.
		 * Yes, this might clear the entropy pool if the wrong
		 * driver is attempted to be loaded, without actually
		 * installing a new handler, but is this really a problem,
		 * only the sysadmin is able to do this.
		 */
		rand_initialize_irq(irq);
	}

	/*
	 * The following block of code has to be executed atomically
	 */
	spin_lock_irqsave(&desc->lock,flags);
	p = &desc->action;
	if ((old = *p) != NULL) {
		/* Can't share interrupts unless both agree to */
		if (!(old->flags & new->flags & SA_SHIRQ)) {
			spin_unlock_irqrestore(&desc->lock,flags);
			return -EBUSY;
		}

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

	*p = new;

	if (!shared) {
		desc->depth = 0;
		desc->status &= ~(IRQ_DISABLED | IRQ_AUTODETECT | IRQ_WAITING | IRQ_INPROGRESS);
		if (desc->handler && desc->handler->startup)
			desc->handler->startup(irq);
		unmask_irq(irq);
	}
	spin_unlock_irqrestore(&desc->lock,flags);

	register_irq_proc(irq);
	return 0;
}

#ifdef CONFIG_SMP

inline void synchronize_irq(unsigned int irq)
{
	while (get_irq_desc(irq)->status & IRQ_INPROGRESS)
		cpu_relax();
}

EXPORT_SYMBOL(synchronize_irq);

#endif /* CONFIG_SMP */

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

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

	action = (struct irqaction *)
		kmalloc(sizeof(struct irqaction), GFP_KERNEL);
	if (!action) {
		printk(KERN_ERR "kmalloc() failed for irq %d !\n", irq);
		return -ENOMEM;
	}

	action->handler = handler;
	action->flags = irqflags;
	cpus_clear(action->mask);
	action->name = devname;
	action->dev_id = dev_id;
	action->next = NULL;

	retval = setup_irq(irq, action);
	if (retval)
		kfree(action);

	return 0;
}

EXPORT_SYMBOL(request_irq);

void free_irq(unsigned int irq, void *dev_id)
{
	irq_desc_t *desc = get_irq_desc(irq);
	struct irqaction **p;
	unsigned long flags;

	spin_lock_irqsave(&desc->lock,flags);
	p = &desc->action;
	for (;;) {
		struct irqaction * action = *p;
		if (action) {
			struct irqaction **pp = p;
			p = &action->next;
			if (action->dev_id != dev_id)
				continue;

			/* Found it - now remove it from the list of entries */
			*pp = action->next;
			if (!desc->action) {
				desc->status |= IRQ_DISABLED;
				mask_irq(irq);
			}
			spin_unlock_irqrestore(&desc->lock,flags);

			/* Wait to make sure it's not being used on another CPU */
			synchronize_irq(irq);
			kfree(action);
			return;
		}
		printk("Trying to free free IRQ%d\n",irq);
		spin_unlock_irqrestore(&desc->lock,flags);
		break;
	}
	return;
}

EXPORT_SYMBOL(free_irq);

/*
 * Generic enable/disable code: this just calls
 * down into the PIC-specific version for the actual
 * hardware disable after having gotten the irq
 * controller lock. 
 */
 
/**
 *	disable_irq_nosync - disable an irq without waiting
 *	@irq: Interrupt to disable
 *
 *	Disable the selected interrupt line. Disables of an interrupt
 *	stack. Unlike disable_irq(), this function does not ensure existing
 *	instances of the IRQ handler have completed before returning.
 *
 *	This function may be called from IRQ context.
 */
 
inline void disable_irq_nosync(unsigned int irq)
{
	irq_desc_t *desc = get_irq_desc(irq);
	unsigned long flags;

	spin_lock_irqsave(&desc->lock, flags);
	if (!desc->depth++) {
		if (!(desc->status & IRQ_PER_CPU))
			desc->status |= IRQ_DISABLED;
		mask_irq(irq);
	}
	spin_unlock_irqrestore(&desc->lock, flags);
}

EXPORT_SYMBOL(disable_irq_nosync);

/**
 *	disable_irq - disable an irq and wait for completion
 *	@irq: Interrupt to disable
 *
 *	Disable the selected interrupt line. Disables of an interrupt
 *	stack. That is for two disables you need two enables. This
 *	function waits for any pending IRQ handlers for this interrupt
 *	to complete before returning. If you use this function while
 *	holding a resource the IRQ handler may need you will deadlock.
 *
 *	This function may be called - with care - from IRQ context.
 */
 
void disable_irq(unsigned int irq)
{
	irq_desc_t *desc = get_irq_desc(irq);
	disable_irq_nosync(irq);
	if (desc->action)
		synchronize_irq(irq);
}

EXPORT_SYMBOL(disable_irq);

/**
 *	enable_irq - enable interrupt handling on an irq
 *	@irq: Interrupt to enable
 *
 *	Re-enables the processing of interrupts on this IRQ line
 *	providing no disable_irq calls are now in effect.
 *
 *	This function may be called from IRQ context.
 */
 
void enable_irq(unsigned int irq)
{
	irq_desc_t *desc = get_irq_desc(irq);
	unsigned long flags;

	spin_lock_irqsave(&desc->lock, flags);
	switch (desc->depth) {
	case 1: {
		unsigned int status = desc->status & ~IRQ_DISABLED;
		desc->status = status;
		if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
			desc->status = status | IRQ_REPLAY;
			hw_resend_irq(desc->handler,irq);
		}
		unmask_irq(irq);
		/* fall-through */
	}
	default:
		desc->depth--;
		break;
	case 0:
		printk("enable_irq(%u) unbalanced from %p\n", irq,
		       __builtin_return_address(0));
	}
	spin_unlock_irqrestore(&desc->lock, flags);
}

EXPORT_SYMBOL(enable_irq);

int show_interrupts(struct seq_file *p, void *v)
{
	int i = *(loff_t *) v, j;
	struct irqaction * action;
	irq_desc_t *desc;
	unsigned long flags;

	if (i == 0) {
		seq_printf(p, "           ");
		for (j=0; j<NR_CPUS; j++) {
			if (cpu_online(j))
				seq_printf(p, "CPU%d       ",j);
		}
		seq_putc(p, '\n');
	}

	if (i < NR_IRQS) {
		desc = get_irq_desc(i);
		spin_lock_irqsave(&desc->lock, flags);
		action = desc->action;
		if (!action || !action->handler)
			goto skip;
		seq_printf(p, "%3d: ", i);
#ifdef CONFIG_SMP
		for (j = 0; j < NR_CPUS; j++) {
			if (cpu_online(j))
				seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
		}
#else
		seq_printf(p, "%10u ", kstat_irqs(i));
#endif /* CONFIG_SMP */
		if (desc->handler)
			seq_printf(p, " %s ", desc->handler->typename );
		else
			seq_printf(p, "  None      ");
		seq_printf(p, "%s", (desc->status & IRQ_LEVEL) ? "Level " : "Edge  ");
		seq_printf(p, "    %s",action->name);
		for (action=action->next; action; action = action->next)
			seq_printf(p, ", %s", action->name);
		seq_putc(p, '\n');
skip:
		spin_unlock_irqrestore(&desc->lock, flags);
	} else if (i == NR_IRQS)
		seq_printf(p, "BAD: %10u\n", ppc_spurious_interrupts);
	return 0;
}

int handle_irq_event(int irq, struct pt_regs *regs, struct irqaction *action)
{
	int status = 0;
	int retval = 0;

	if (!(action->flags & SA_INTERRUPT))
		local_irq_enable();

	do {
		status |= action->flags;
		retval |= action->handler(irq, action->dev_id, regs);
		action = action->next;
	} while (action);
	if (status & SA_SAMPLE_RANDOM)
		add_interrupt_randomness(irq);
	local_irq_disable();
	return retval;
}

static void __report_bad_irq(int irq, irq_desc_t *desc, irqreturn_t action_ret)
{
	struct irqaction *action;

	if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
		printk(KERN_ERR "irq event %d: bogus return value %x\n",
				irq, action_ret);
	} else {
		printk(KERN_ERR "irq %d: nobody cared!\n", irq);
	}
	dump_stack();
	printk(KERN_ERR "handlers:\n");
	action = desc->action;
	do {
		printk(KERN_ERR "[<%p>]", action->handler);
		print_symbol(" (%s)",
			(unsigned long)action->handler);
		printk("\n");
		action = action->next;
	} while (action);
}

static void report_bad_irq(int irq, irq_desc_t *desc, irqreturn_t action_ret)
{
	static int count = 100;

	if (count) {
		count--;
		__report_bad_irq(irq, desc, action_ret);
	}
}

static int noirqdebug;

static int __init noirqdebug_setup(char *str)
{
	noirqdebug = 1;
	printk("IRQ lockup detection disabled\n");
	return 1;
}

__setup("noirqdebug", noirqdebug_setup);

/*
 * If 99,900 of the previous 100,000 interrupts have not been handled then
 * assume that the IRQ is stuck in some manner.  Drop a diagnostic and try to
 * turn the IRQ off.
 *
 * (The other 100-of-100,000 interrupts may have been a correctly-functioning
 *  device sharing an IRQ with the failing one)
 *
 * Called under desc->lock
 */
static void note_interrupt(int irq, irq_desc_t *desc, irqreturn_t action_ret)
{
	if (action_ret != IRQ_HANDLED) {
		desc->irqs_unhandled++;
		if (action_ret != IRQ_NONE)
			report_bad_irq(irq, desc, action_ret);
	}

	desc->irq_count++;
	if (desc->irq_count < 100000)
		return;

	desc->irq_count = 0;
	if (desc->irqs_unhandled > 99900) {
		/*
		 * The interrupt is stuck
		 */
		__report_bad_irq(irq, desc, action_ret);
		/*
		 * Now kill the IRQ
		 */
		printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
		desc->status |= IRQ_DISABLED;
		desc->handler->disable(irq);
	}
	desc->irqs_unhandled = 0;
}

/*
 * Eventually, this should take an array of interrupts and an array size
 * so it can dispatch multiple interrupts.
 */
void ppc_irq_dispatch_handler(struct pt_regs *regs, int irq)
{
	int status;
	struct irqaction *action;
	int cpu = smp_processor_id();
	irq_desc_t *desc = get_irq_desc(irq);
	irqreturn_t action_ret;
#ifdef CONFIG_IRQSTACKS
	struct thread_info *curtp, *irqtp;
#endif

	kstat_cpu(cpu).irqs[irq]++;

	if (desc->status & IRQ_PER_CPU) {
		/* no locking required for CPU-local interrupts: */
		ack_irq(irq);
		action_ret = handle_irq_event(irq, regs, desc->action);
		desc->handler->end(irq);
		return;
	}

	spin_lock(&desc->lock);
	ack_irq(irq);	
	/*
	   REPLAY is when Linux resends an IRQ that was dropped earlier
	   WAITING is used by probe to mark irqs that are being tested
	   */
	status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
	status |= IRQ_PENDING; /* we _want_ to handle it */

	/*
	 * If the IRQ is disabled for whatever reason, we cannot
	 * use the action we have.
	 */
	action = NULL;
	if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
		action = desc->action;
		if (!action || !action->handler) {
			ppc_spurious_interrupts++;
			printk(KERN_DEBUG "Unhandled interrupt %x, disabled\n", irq);
			/* We can't call disable_irq here, it would deadlock */
			if (!desc->depth)
				desc->depth = 1;
			desc->status |= IRQ_DISABLED;