irq.c

一个2.4.21版本的嵌入式linux内核

/*
 *  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/ptrace.h>
#include <linux/errno.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/seq_file.h>
#include <linux/random.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>
#include <asm/perfmon.h>

#include "local_irq.h"

atomic_t ipi_recv;
atomic_t ipi_sent;
void enable_irq(unsigned int irq_nr);
void disable_irq(unsigned int irq_nr);

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

volatile unsigned char *chrp_int_ack_special;
static void register_irq_proc (unsigned int irq);

irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned =
	{ [0 ... NR_IRQS-1] = { 0, NULL, NULL, 0, SPIN_LOCK_UNLOCKED}};
	
int ppc_spurious_interrupts = 0;
struct irqaction *ppc_irq_action[NR_IRQS];
unsigned long lpEvent_count = 0;
#ifdef CONFIG_XMON
extern void xmon(struct pt_regs *regs);
extern int xmon_bpt(struct pt_regs *regs);
extern int xmon_sstep(struct pt_regs *regs);
extern int xmon_iabr_match(struct pt_regs *regs);
extern int xmon_dabr_match(struct pt_regs *regs);
extern void (*xmon_fault_handler)(struct pt_regs *regs);
#endif
#ifdef CONFIG_XMON
extern void (*debugger)(struct pt_regs *regs);
extern int (*debugger_bpt)(struct pt_regs *regs);
extern int (*debugger_sstep)(struct pt_regs *regs);
extern int (*debugger_iabr_match)(struct pt_regs *regs);
extern int (*debugger_dabr_match)(struct pt_regs *regs);
extern void (*debugger_fault_handler)(struct pt_regs *regs);
#endif

/* nasty hack for shared irq's since we need to do kmalloc calls but
 * can't very early in the boot when we need to do a request irq.
 * this needs to be removed.
 * -- Cort
 */
#define IRQ_KMALLOC_ENTRIES 16
static int cache_bitmask = 0;
static struct irqaction malloc_cache[IRQ_KMALLOC_ENTRIES];
extern int mem_init_done;

void *irq_kmalloc(size_t size, int pri)
{
	unsigned int i;
	if ( mem_init_done )
		return kmalloc(size,pri);
	for ( i = 0; i < IRQ_KMALLOC_ENTRIES ; i++ )
		if ( ! ( cache_bitmask & (1<<i) ) ) {
			cache_bitmask |= (1<<i);
			return (void *)(&malloc_cache[i]);
		}
	return 0;
}

void irq_kfree(void *ptr)
{
	unsigned int i;
	for ( i = 0 ; i < IRQ_KMALLOC_ENTRIES ; i++ )
		if ( ptr == &malloc_cache[i] ) {
			cache_bitmask &= ~(1<<i);
			return;
		}
	kfree(ptr);
}

int
setup_irq(unsigned int irq, struct irqaction * new)
{
	int shared = 0;
	unsigned long flags;
	struct irqaction *old, **p;
	irq_desc_t *desc = 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);
		unmask_irq(irq);
	}
	spin_unlock_irqrestore(&desc->lock,flags);

	register_irq_proc(irq);
	return 0;
}

/* This could be promoted to a real free_irq() ... */
static int
do_free_irq(int irq, void* dev_id)
{
	irq_desc_t *desc;
	struct irqaction **p;
	unsigned long flags;

	desc = irq_desc + irq;
	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);

#ifdef CONFIG_SMP
			/* Wait to make sure it's not being used on another CPU */
			while (desc->status & IRQ_INPROGRESS)
				barrier();
#endif
			irq_kfree(action);
			return 0;
		}
		printk("Trying to free free IRQ%d\n",irq);
		spin_unlock_irqrestore(&desc->lock,flags);
		break;
	}
	return -ENOENT;
}

int request_irq(unsigned int irq, void (*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)
		/* We could implement really free_irq() instead of that... */
		return do_free_irq(irq, dev_id);
	
	action = (struct irqaction *)
		irq_kmalloc(sizeof(struct irqaction), GFP_KERNEL);
	if (!action) {
		printk(KERN_ERR "irq_kmalloc() failed for irq %d !\n", irq);
		return -ENOMEM;
	}
	
	action->handler = handler;
	action->flags = irqflags;					
	action->mask = 0;
	action->name = devname;
	action->dev_id = dev_id;
	action->next = NULL;
	
	retval = setup_irq(irq, action);
	if (retval)
		kfree(action);
		
	return 0;
}

void free_irq(unsigned int irq, void *dev_id)
{
	request_irq(irq, NULL, 0, NULL, dev_id);
}

/*
 * 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.
 */
 
 void disable_irq_nosync(unsigned int irq)
{
	irq_desc_t *desc = 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);
}

/**
 *	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)
{
	disable_irq_nosync(irq);

	if (!local_irq_count(smp_processor_id())) {
		do {
			barrier();
		} while (irq_desc[irq].status & IRQ_INPROGRESS);
	}
}

/**
 *	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 = 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\n", irq);
	}
	spin_unlock_irqrestore(&desc->lock, flags);
}

/* one would think this function has one foot in the grave */
int get_irq_list(char *buf)
{
   int i, len = 0, j;
   struct irqaction * action;

   len += sprintf(buf+len, "           ");
   for (j=0; j<smp_num_cpus; j++)
       len += sprintf(buf+len, "CPU%d       ",j);
   *(char *)(buf+len++) = '\n';

   for (i = 0 ; i < NR_IRQS ; i++) {
       action = irq_desc[i].action;
       if ( !action || !action->handler )
           continue;
       len += sprintf(buf+len, "%3d: ", i);
#ifdef CONFIG_SMP
       for (j = 0; j < smp_num_cpus; j++)
           len += sprintf(buf+len, "%10u ",
               kstat.irqs[cpu_logical_map(j)][i]);
#else
       len += sprintf(buf+len, "%10u ", kstat_irqs(i));
#endif /* CONFIG_SMP */
if ( irq_desc[i].handler )
len += sprintf(buf+len, " %s ", irq_desc[i].handler->typename );
else
len += sprintf(buf+len, "  None      ");
len += sprintf(buf+len, "%s", (irq_desc[i].status & IRQ_LEVEL) ? "Level " : "Edge  ");
len += sprintf(buf+len, "    %s",action->name);
for (action=action->next; action; action = action->next) {
len += sprintf(buf+len, ", %s", action->name);
}
len += sprintf(buf+len, "\n");
}
#ifdef CONFIG_SMP
/* should this be per processor send/receive? */
len += sprintf(buf+len, "IPI (recv/sent): %10u/%u\n",
atomic_read(&ipi_recv), atomic_read(&ipi_sent));
#endif
len += sprintf(buf+len, "BAD: %10u\n", ppc_spurious_interrupts);
return len;
}



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

	seq_printf(p, "           ");
	for (j=0; j<smp_num_cpus; j++)
		seq_printf(p, "CPU%d       ",j);
	seq_putc(p, '\n');

	for (i = 0 ; i < NR_IRQS ; i++) {
		action = irq_desc[i].action;
		if (!action || !action->handler)
			continue;
		seq_printf(p, "%3d: ", i);		
#ifdef CONFIG_SMP
		for (j = 0; j < smp_num_cpus; j++)
			seq_printf(p, "%10u ",
				kstat.irqs[cpu_logical_map(j)][i]);
#else		
		seq_printf(p, "%10u ", kstat_irqs(i));
#endif /* CONFIG_SMP */
		if (irq_desc[i].handler)		
			seq_printf(p, " %s ", irq_desc[i].handler->typename );
		else
			seq_printf(p, "  None      ");
		seq_printf(p, "%s", (irq_desc[i].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');
	}
#ifdef CONFIG_SMP
	/* should this be per processor send/receive? */
	seq_printf(p, "IPI (recv/sent): %10u/%u\n",
		       atomic_read(&ipi_recv), atomic_read(&ipi_sent));
#endif		
	seq_printf(p, "BAD: %10u\n", ppc_spurious_interrupts);
	return 0;
}

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

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

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

/*
 * 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 = irq_desc + irq;

	kstat.irqs[cpu][irq]++;
	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);
	if (!(status & IRQ_PER_CPU))
		status |= IRQ_PENDING; /* we _want_ to handle it */

	/*
	 * If the IRQ is disabled for whatever reason, we cannot
	 * use the action we have.
	 */