irq.c 19.8 KB
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/*
 *  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 (gdt@linuxppc.org)
 *  Updated and modified by Cort Dougan (cort@cs.nmt.edu)
 *    Copyright (C) 1996 Cort Dougan
 *  Adapted for Power Macintosh by Paul Mackerras
 *    Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
 *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
 * 
 * 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/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>
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#include <asm/paca.h>
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#include "local_irq.h"

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;

/* 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
 */
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#define IRQ_KMALLOC_ENTRIES 16
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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;
}

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#ifdef CONFIG_SMP

inline void synchronize_irq(unsigned int irq)
{
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	/* is there anything to synchronize with? */
	if (!irq_desc[irq].action)
		return;

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	while (irq_desc[irq].status & IRQ_INPROGRESS)
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		cpu_relax();
}

#endif /* CONFIG_SMP */

/* XXX Make this into free_irq() - Anton */

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/* 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);

			/* Wait to make sure it's not being used on another CPU */
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			synchronize_irq(irq);
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			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);
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	synchronize_irq(irq);
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}

/**
 *	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);
}

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

	seq_printf(p, "           ");
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	for (j=0; j<NR_CPUS; j++) {
		if (cpu_online(j))
			seq_printf(p, "CPU%d       ",j);
	}
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	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
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		for (j = 0; j < NR_CPUS; j++) {
			if (cpu_online(j))
				seq_printf(p, "%10u ", kstat.irqs[j][i]);
		}
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#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');
	}
	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))
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		local_irq_enable();
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	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);
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	local_irq_disable();
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}

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#ifdef CONFIG_SMP
extern unsigned int irq_affinity [NR_IRQS];

typedef struct {
	unsigned long cpu;
	unsigned long timestamp;
} ____cacheline_aligned irq_balance_t;

static irq_balance_t irq_balance[NR_IRQS] __cacheline_aligned
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			= { [ 0 ... NR_IRQS-1 ] = { 0, 0 } };
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#define IDLE_ENOUGH(cpu,now) \
		(idle_cpu(cpu) && ((now) - irq_stat[(cpu)].idle_timestamp > ((HZ/100)+1)))

#define IRQ_ALLOWED(cpu,allowed_mask) \
		((1 << cpu) & (allowed_mask))

static unsigned long move(unsigned long curr_cpu, unsigned long allowed_mask,
			  unsigned long now, int direction)
{
	int search_idle = 1;
	int cpu = curr_cpu;

	goto inside;

	do {
		if (unlikely(cpu == curr_cpu))
			search_idle = 0;
inside:
		if (direction == 1) {
			cpu++;
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			if (cpu >= NR_CPUS)
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				cpu = 0;
		} else {
			cpu--;
			if (cpu == -1)
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				cpu = NR_CPUS-1;
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		}
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	} while (!cpu_online(cpu) || !IRQ_ALLOWED(cpu,allowed_mask) ||
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			(search_idle && !IDLE_ENOUGH(cpu,now)));

	return cpu;
}

static inline void balance_irq(int irq)
{
	irq_balance_t *entry = irq_balance + irq;
	unsigned long now = jiffies;

	if (unlikely(entry->timestamp != now)) {
		unsigned long allowed_mask;
		unsigned long random_number;

		if (!irq_desc[irq].handler->set_affinity)
			return;

		random_number = mftb();
		random_number &= 1;

		allowed_mask = cpu_online_map & irq_affinity[irq];
		entry->timestamp = now;
		entry->cpu = move(entry->cpu, allowed_mask, now, random_number);
		irq_desc[irq].handler->set_affinity(irq, 1 << entry->cpu);
	}
}
#else
#define balance_irq(irq) do { } while (0)
#endif

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/*
 * 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;

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	/* XXX This causes bad performance and lockups on XICS - Anton */
	if (naca->interrupt_controller == IC_OPEN_PIC)
		balance_irq(irq);
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	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.
	 */
	action = NULL;
	if (!(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;
			/* This is not a real spurrious interrupt, we
			 * have to eoi it, so we jump to out
			 */
			mask_irq(irq);
			goto out;
		}
		status &= ~IRQ_PENDING; /* we commit to handling */
		if (!(status & IRQ_PER_CPU))
			status |= IRQ_INPROGRESS; /* we are handling it */
	}
	desc->status = status;

	/*
	 * If there is no IRQ handler or it was disabled, exit early.
	   Since we set PENDING, if another processor is handling
	   a different instance of this same irq, the other processor
	   will take care of it.
	 */
	if (!action)
		goto out;


	/*
	 * Edge triggered interrupts need to remember
	 * pending events.
	 * This applies to any hw interrupts that allow a second
	 * instance of the same irq to arrive while we are in do_IRQ
	 * or in the handler. But the code here only handles the _second_
	 * instance of the irq, not the third or fourth. So it is mostly
	 * useful for irq hardware that does not mask cleanly in an
	 * SMP environment.
	 */
	for (;;) {
		spin_unlock(&desc->lock);
		handle_irq_event(irq, regs, action);
		spin_lock(&desc->lock);
		
		if (!(desc->status & IRQ_PENDING))
			break;
		desc->status &= ~IRQ_PENDING;
	}
	desc->status &= ~IRQ_INPROGRESS;
out:
	/*
	 * The ->end() handler has to deal with interrupts which got
	 * disabled while the handler was running.
	 */
	if (irq_desc[irq].handler) {
		if (irq_desc[irq].handler->end)
			irq_desc[irq].handler->end(irq);
		else if (irq_desc[irq].handler->enable)
			irq_desc[irq].handler->enable(irq);
	}
	spin_unlock(&desc->lock);
}

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int do_IRQ(struct pt_regs *regs)
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{
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	int irq, first = 1;
#ifdef CONFIG_PPC_ISERIES
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	struct paca_struct *lpaca;
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	struct ItLpQueue *lpq;
#endif
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	irq_enter();
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#ifdef CONFIG_PPC_ISERIES
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	lpaca = get_paca();
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#ifdef CONFIG_SMP
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	if (lpaca->xLpPaca.xIntDword.xFields.xIpiCnt) {
		lpaca->xLpPaca.xIntDword.xFields.xIpiCnt = 0;
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		iSeries_smp_message_recv(regs);
	}
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#endif /* CONFIG_SMP */
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	lpq = lpaca->lpQueuePtr;
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	if (lpq && ItLpQueue_isLpIntPending(lpq))
		lpEvent_count += ItLpQueue_process(lpq, regs);
#else
	/*
	 * Every arch is required to implement ppc_md.get_irq.
	 * This function will either return an irq number or -1 to
	 * indicate there are no more pending.  But the first time
	 * through the loop this means there wasn't an IRQ pending.
	 * The value -2 is for buggy hardware and means that this IRQ
	 * has already been handled. -- Tom
	 */
	while ((irq = ppc_md.get_irq(regs)) >= 0) {
		ppc_irq_dispatch_handler(regs, irq);
		first = 0;
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	}
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	if (irq != -2 && first)
		/* That's not SMP safe ... but who cares ? */
		ppc_spurious_interrupts++;
#endif

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	irq_exit();
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#ifdef CONFIG_PPC_ISERIES
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	if (lpaca->xLpPaca.xIntDword.xFields.xDecrInt) {
		lpaca->xLpPaca.xIntDword.xFields.xDecrInt = 0;
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		/* Signal a fake decrementer interrupt */
		timer_interrupt(regs);
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	}
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#endif
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	return 1; /* lets ret_from_int know we can do checks */
}

unsigned long probe_irq_on (void)
{
	return 0;
}

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

unsigned int probe_irq_mask(unsigned long irqs)
{
	return 0;
}

void __init init_IRQ(void)
{
	static int once = 0;

	if ( once )
		return;
	else
		once++;
	
	ppc_md.init_IRQ();
	if(ppc_md.init_ras_IRQ) ppc_md.init_ras_IRQ(); 
}

static struct proc_dir_entry * root_irq_dir;
static struct proc_dir_entry * irq_dir [NR_IRQS];
static struct proc_dir_entry * smp_affinity_entry [NR_IRQS];

#ifdef CONFIG_IRQ_ALL_CPUS
unsigned int irq_affinity [NR_IRQS] = { [0 ... NR_IRQS-1] = 0xffffffff};
#else  /* CONFIG_IRQ_ALL_CPUS */
unsigned int irq_affinity [NR_IRQS] = { [0 ... NR_IRQS-1] = 0x00000000};
#endif /* CONFIG_IRQ_ALL_CPUS */

#define HEX_DIGITS 8

static int irq_affinity_read_proc (char *page, char **start, off_t off,
			int count, int *eof, void *data)
{
	if (count < HEX_DIGITS+1)
		return -EINVAL;
	return sprintf (page, "%08x\n", irq_affinity[(int)(long)data]);
}

static unsigned int parse_hex_value (const char *buffer,
		unsigned long count, unsigned long *ret)
{
	unsigned char hexnum [HEX_DIGITS];
	unsigned long value;
	int i;

	if (!count)
		return -EINVAL;
	if (count > HEX_DIGITS)
		count = HEX_DIGITS;
	if (copy_from_user(hexnum, buffer, count))
		return -EFAULT;

	/*
	 * Parse the first 8 characters as a hex string, any non-hex char
	 * is end-of-string. '00e1', 'e1', '00E1', 'E1' are all the same.
	 */
	value = 0;

	for (i = 0; i < count; i++) {
		unsigned int c = hexnum[i];

		switch (c) {
			case '0' ... '9': c -= '0'; break;
			case 'a' ... 'f': c -= 'a'-10; break;
			case 'A' ... 'F': c -= 'A'-10; break;
		default:
			goto out;
		}
		value = (value << 4) | c;
	}
out:
	*ret = value;
	return 0;
}

static int irq_affinity_write_proc (struct file *file, const char *buffer,
					unsigned long count, void *data)
{
	int irq = (int)(long) data, full_count = count, err;
	unsigned long new_value;

	if (!irq_desc[irq].handler->set_affinity)
		return -EIO;

	err = parse_hex_value(buffer, count, &new_value);

/* Why is this disabled ? --BenH */
#if 0/*CONFIG_SMP*/
	/*
	 * Do not allow disabling IRQs completely - it's a too easy
	 * way to make the system unusable accidentally :-) At least
	 * one online CPU still has to be targeted.
	 */
	if (!(new_value & cpu_online_map))
		return -EINVAL;
#endif

	irq_affinity[irq] = new_value;
	irq_desc[irq].handler->set_affinity(irq, new_value);

	return full_count;
}

static int prof_cpu_mask_read_proc (char *page, char **start, off_t off,
			int count, int *eof, void *data)
{
	unsigned long *mask = (unsigned long *) data;
	if (count < HEX_DIGITS+1)
		return -EINVAL;
	return sprintf (page, "%08lx\n", *mask);
}

static int prof_cpu_mask_write_proc (struct file *file, const char *buffer,
					unsigned long count, void *data)
{
	unsigned long *mask = (unsigned long *) data, full_count = count, err;
	unsigned long new_value;

	err = parse_hex_value(buffer, count, &new_value);
	if (err)
		return err;

	*mask = new_value;

#ifdef CONFIG_PPC_ISERIES
	{
		unsigned i;
759 760 761
		for (i=0; i<MAX_PACAS; ++i) {
			if ( paca[i].prof_buffer && (new_value & 1) )
				paca[i].prof_enabled = 1;
762
			else
763
				paca[i].prof_enabled = 0;
764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829
			new_value >>= 1;
		}
	}
#endif

	return full_count;
}

#define MAX_NAMELEN 10

static void register_irq_proc (unsigned int irq)
{
	struct proc_dir_entry *entry;
	char name [MAX_NAMELEN];

	if (!root_irq_dir || (irq_desc[irq].handler == NULL))
		return;

	memset(name, 0, MAX_NAMELEN);
	sprintf(name, "%d", irq);

	/* create /proc/irq/1234 */
	irq_dir[irq] = proc_mkdir(name, root_irq_dir);

	/* create /proc/irq/1234/smp_affinity */
	entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);

	entry->nlink = 1;
	entry->data = (void *)(long)irq;
	entry->read_proc = irq_affinity_read_proc;
	entry->write_proc = irq_affinity_write_proc;

	smp_affinity_entry[irq] = entry;
}

unsigned long prof_cpu_mask = -1;

void init_irq_proc (void)
{
	struct proc_dir_entry *entry;
	int i;

	/* create /proc/irq */
	root_irq_dir = proc_mkdir("irq", 0);

	/* create /proc/irq/prof_cpu_mask */
	entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir);

	entry->nlink = 1;
	entry->data = (void *)&prof_cpu_mask;
	entry->read_proc = prof_cpu_mask_read_proc;
	entry->write_proc = prof_cpu_mask_write_proc;

	/*
	 * Create entries for all existing IRQs.
	 */
	for (i = 0; i < NR_IRQS; i++) {
		if (irq_desc[i].handler == NULL)
			continue;
		register_irq_proc(i);
	}
}

void no_action(int irq, void *dev, struct pt_regs *regs)
{
}