irq.c

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

/* 
 * Code to handle x86 style IRQs plus some generic interrupt stuff.
 *
 * Copyright (C) 1992 Linus Torvalds
 * Copyright (C) 1994, 1995, 1996, 1997, 1998 Ralf Baechle
 * Copyright (C) 1999 SuSE GmbH (Philipp Rumpf, [e-mail])
 * Copyright (C) 1999-2000 Grant Grundler
 *
 *    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, or (at your option)
 *    any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include <linux/bitops.h>
#include <asm/bitops.h>
#include <linux/config.h>
#include <asm/pdc.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/signal.h>
#include <linux/types.h>
#include <linux/ioport.h>
#include <linux/timex.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/irq.h>
#include <linux/spinlock.h>

#include <asm/cache.h>

#undef DEBUG_IRQ
#undef PARISC_IRQ_CR16_COUNTS

extern void timer_interrupt(int, void *, struct pt_regs *);
extern void ipi_interrupt(int, void *, struct pt_regs *);

#ifdef DEBUG_IRQ
#define DBG_IRQ(irq, x)	if ((irq) != TIMER_IRQ) printk x
#else /* DEBUG_IRQ */
#define DBG_IRQ(irq, x)	do { } while (0)
#endif /* DEBUG_IRQ */

#define EIEM_MASK(irq)       (1UL<<(MAX_CPU_IRQ-IRQ_OFFSET(irq)))

/* Bits in EIEM correlate with cpu_irq_action[].
** Numbered *Big Endian*! (ie bit 0 is MSB)
*/
static unsigned long cpu_eiem = 0;

static spinlock_t irq_lock = SPIN_LOCK_UNLOCKED;  /* protect IRQ regions */

#ifdef CONFIG_SMP
static void cpu_set_eiem(void *info)
{
	set_eiem((unsigned long) info);
}
#endif

static inline void disable_cpu_irq(void *unused, int irq)
{
	unsigned long eirr_bit = EIEM_MASK(irq);

	cpu_eiem &= ~eirr_bit;
	set_eiem(cpu_eiem);
        smp_call_function(cpu_set_eiem, (void *) cpu_eiem, 1, 1);
}

static void enable_cpu_irq(void *unused, int irq)
{
	unsigned long eirr_bit = EIEM_MASK(irq);

	mtctl(eirr_bit, 23);	/* clear EIRR bit before unmasking */
	cpu_eiem |= eirr_bit;
        smp_call_function(cpu_set_eiem, (void *) cpu_eiem, 1, 1);
	set_eiem(cpu_eiem);
}

/* mask and disable are the same at the CPU level
** Difference is enable clears pending interrupts
*/
#define mask_cpu_irq	disable_cpu_irq

static inline void unmask_cpu_irq(void *unused, int irq)
{
	unsigned long eirr_bit = EIEM_MASK(irq);
	cpu_eiem |= eirr_bit;
	/* NOTE: sending an IPI will cause do_cpu_irq_mask() to
	** handle *any* unmasked pending interrupts.
	** ie We don't need to check for pending interrupts here.
	*/
        smp_call_function(cpu_set_eiem, (void *) cpu_eiem, 1, 1);
	set_eiem(cpu_eiem);
}

/*
 * XXX cpu_irq_actions[] will become 2 dimensional for per CPU EIR support.
 * correspond changes needed in:
 * 	processor_probe()	initialize additional action arrays
 * 	request_irq()		handle CPU IRQ region specially
 * 	do_cpu_irq_mask()	index into the matching irq_action array.
 */
struct irqaction cpu_irq_actions[IRQ_PER_REGION] = {
	[IRQ_OFFSET(TIMER_IRQ)] { handler: timer_interrupt, name: "timer", },
#ifdef CONFIG_SMP
	[IRQ_OFFSET(IPI_IRQ)]	{ handler: ipi_interrupt,   name: "IPI", },
#endif
};

struct irq_region_ops cpu_irq_ops = {
	disable_cpu_irq, enable_cpu_irq, unmask_cpu_irq, unmask_cpu_irq
};

struct irq_region cpu0_irq_region = {
	ops:	{ disable_cpu_irq, enable_cpu_irq, unmask_cpu_irq, unmask_cpu_irq },
	data:	{ dev: &cpu_data[0],
		  name: "PARISC-CPU",
		  irqbase: IRQ_FROM_REGION(CPU_IRQ_REGION), },
	action:	cpu_irq_actions,
};

struct irq_region *irq_region[NR_IRQ_REGS] = {
	[ 0 ]              NULL, /* reserved for EISA, else causes data page fault (aka code 15) */
	[ CPU_IRQ_REGION ] &cpu0_irq_region,
};


/*
** Generic interfaces that device drivers can use:
**    mask_irq()	block IRQ
**    unmask_irq()	re-enable IRQ and trigger if IRQ is pending
**    disable_irq()	block IRQ
**    enable_irq()	clear pending and re-enable IRQ
*/

void mask_irq(int irq)
{
	struct irq_region *region;

	DBG_IRQ(irq, ("mask_irq(%d) %d+%d eiem 0x%lx\n", irq,
				IRQ_REGION(irq), IRQ_OFFSET(irq), cpu_eiem));
	irq = irq_cannonicalize(irq);
	region = irq_region[IRQ_REGION(irq)];
	if (region->ops.mask_irq)
		region->ops.mask_irq(region->data.dev, IRQ_OFFSET(irq));
}

void unmask_irq(int irq)
{
	struct irq_region *region;

	DBG_IRQ(irq, ("unmask_irq(%d) %d+%d eiem 0x%lx\n", irq,
				IRQ_REGION(irq), IRQ_OFFSET(irq), cpu_eiem));
	irq = irq_cannonicalize(irq);
	region = irq_region[IRQ_REGION(irq)];
	if (region->ops.unmask_irq)
		region->ops.unmask_irq(region->data.dev, IRQ_OFFSET(irq));
}

void disable_irq(int irq)
{
	struct irq_region *region;

	DBG_IRQ(irq, ("disable_irq(%d) %d+%d eiem 0x%lx\n", irq,
				IRQ_REGION(irq), IRQ_OFFSET(irq), cpu_eiem));
	irq = irq_cannonicalize(irq);
	region = irq_region[IRQ_REGION(irq)];
	if (region->ops.disable_irq)
		region->ops.disable_irq(region->data.dev, IRQ_OFFSET(irq));
	else
		BUG();
}

void enable_irq(int irq)
{
	struct irq_region *region;

	DBG_IRQ(irq, ("enable_irq(%d) %d+%d eiem 0x%lx\n", irq,
				IRQ_REGION(irq), IRQ_OFFSET(irq), cpu_eiem));
	irq = irq_cannonicalize(irq);
	region = irq_region[IRQ_REGION(irq)];

	if (region->ops.enable_irq)
		region->ops.enable_irq(region->data.dev, IRQ_OFFSET(irq));
	else
		BUG();
}

int get_irq_list(char *buf)
{
#ifdef CONFIG_PROC_FS
	char *p = buf;
	unsigned int regnr;

	p += sprintf(p, "     ");
#ifdef CONFIG_SMP
	for (regnr = 0; regnr < smp_num_cpus; regnr++)
#endif
		p += sprintf(p, "     CPU%02d ", regnr);


#ifdef PARISC_IRQ_CR16_COUNTS
	p += sprintf(p, "[min/avg/max] (CPU cycle counts)");
#endif
	*p++ = '\n';

	/* We don't need *irqsave lock variants since this is
	** only allowed to change while in the base context.
	*/
	spin_lock(&irq_lock);
	for (regnr = 0; regnr < NR_IRQ_REGS; regnr++) {
	    unsigned int i;
	    struct irq_region *region = irq_region[regnr];
#ifdef CONFIG_SMP
	    unsigned int j;
#endif

            if (!region || !region->action)
		continue;

	    for (i = 0; i <= MAX_CPU_IRQ; i++) {
		struct irqaction *action = &region->action[i];
		unsigned int irq_no = IRQ_FROM_REGION(regnr) + i;

		if (!action->handler)
			continue;

		p += sprintf(p, "%3d: ", irq_no);
#ifndef CONFIG_SMP
		p += sprintf(p, "%10u ", kstat_irqs(irq_no));
#else
		for (j = 0; j < smp_num_cpus; j++)
			p += sprintf(p, "%10u ",
				kstat.irqs[j][regnr][i]);
#endif
		p += sprintf(p, " %14s",
			    region->data.name ? region->data.name : "N/A");

#ifndef PARISC_IRQ_CR16_COUNTS
		p += sprintf(p, "  %s", action->name);

		while ((action = action->next))
			p += sprintf(p, ", %s", action->name);
#else
		for ( ;action; action = action->next) {
			unsigned int i, avg, min, max;

			min = max = action->cr16_hist[0];

			for (avg = i = 0; i < PARISC_CR16_HIST_SIZE; i++) {
				int hist = action->cr16_hist[i];

				if (hist) {
					avg += hist;
				} else
					break;

				if (hist > max) max = hist;
				if (hist < min) min = hist;
			}

			avg /= i;
			p += sprintf(p, " %s[%d/%d/%d]", action->name,
					min,avg,max);
		}
#endif

		*p++ = '\n';
	    }
	}
	spin_unlock(&irq_lock);

	p += sprintf(p, "\n");
	return p - buf;

#else	/* CONFIG_PROC_FS */

	return 0;

#endif	/* CONFIG_PROC_FS */
}



/*
** The following form a "set": Virtual IRQ, Transaction Address, Trans Data.
** Respectively, these map to IRQ region+EIRR, Processor HPA, EIRR bit.
**
** To use txn_XXX() interfaces, get a Virtual IRQ first.
** Then use that to get the Transaction address and data.
*/

int
txn_alloc_irq(void)
{
	int irq;

	/* never return irq 0 cause that's the interval timer */
	for (irq = 1; irq <= MAX_CPU_IRQ; irq++) {
		if (cpu_irq_actions[irq].handler == NULL) {
			return (IRQ_FROM_REGION(CPU_IRQ_REGION) + irq);
		}
	}

	/* unlikely, but be prepared */
	return -1;
}

int
txn_claim_irq(int irq)
{
	if (irq_region[IRQ_REGION(irq)]->action[IRQ_OFFSET(irq)].handler ==NULL)
		return irq;

	/* unlikely, but be prepared */
	return -1;
}

unsigned long
txn_alloc_addr(int virt_irq)
{
	static int next_cpu = -1;

	next_cpu++; /* assign to "next" CPU we want this bugger on */

	/* validate entry */
	while ((next_cpu < NR_CPUS) && !cpu_data[next_cpu].txn_addr)
		next_cpu++;

	if (next_cpu >= NR_CPUS) 
		next_cpu = 0;	/* nothing else, assign monarch */

	return cpu_data[next_cpu].txn_addr;
}


/*
** The alloc process needs to accept a parameter to accomodate limitations
** of the HW/SW which use these bits:
** Legacy PA I/O (GSC/NIO): 5 bits (architected EIM register)
** V-class (EPIC):          6 bits
** N/L-class/A500:          8 bits (iosapic)
** PCI 2.2 MSI:             16 bits (I think)
** Existing PCI devices:    32-bits (all Symbios SCSI/ATM/HyperFabric)
**
** On the service provider side:
** o PA 1.1 (and PA2.0 narrow mode)     5-bits (width of EIR register)
** o PA 2.0 wide mode                   6-bits (per processor)
** o IA64                               8-bits (0-256 total)
**
** So a Legacy PA I/O device on a PA 2.0 box can't use all
** the bits supported by the processor...and the N/L-class
** I/O subsystem supports more bits than PA2.0 has. The first
** case is the problem.
*/
unsigned int
txn_alloc_data(int virt_irq, unsigned int bits_wide)
{
	/* XXX FIXME : bits_wide indicates how wide the transaction
	** data is allowed to be...we may need a different virt_irq
	** if this one won't work. Another reason to index virtual
	** irq's into a table which can manage CPU/IRQ bit seperately.
	*/
	if (IRQ_OFFSET(virt_irq) > (1 << (bits_wide -1)))
	{
		panic("Sorry -- didn't allocate valid IRQ for this device\n");
	}

	return (IRQ_OFFSET(virt_irq));
}

void do_irq(struct irqaction *action, int irq, struct pt_regs * regs)
{
	int cpu = smp_processor_id();

	irq_enter(cpu, irq);
	++kstat.irqs[cpu][IRQ_REGION(irq)][IRQ_OFFSET(irq)];

	DBG_IRQ(irq, ("do_irq(%d) %d+%d\n", irq, IRQ_REGION(irq), IRQ_OFFSET(irq)));

	for (; action; action = action->next) {
#ifdef PARISC_IRQ_CR16_COUNTS
		unsigned long cr_start = mfctl(16);
#endif

		if (action->handler == NULL) {
			if (IRQ_REGION(irq) == EISA_IRQ_REGION && irq_region[EISA_IRQ_REGION]) {
				/* were we called due to autodetecting (E)ISA irqs ? */
				unsigned int *status;
				status = &irq_region[EISA_IRQ_REGION]->data.status[IRQ_OFFSET(irq)];
				if (*status & IRQ_AUTODETECT) {
					*status &= ~IRQ_WAITING;
					continue; 
				}
			}
			printk(KERN_ERR "IRQ:  CPU:%d No handler for IRQ %d !\n", cpu, irq);
			continue;
		}

		action->handler(irq, action->dev_id, regs);

#ifdef PARISC_IRQ_CR16_COUNTS
		{
			unsigned long cr_end = mfctl(16);
			unsigned long tmp = cr_end - cr_start;
			/* check for roll over */
			cr_start = (cr_end < cr_start) ?  -(tmp) : (tmp);
		}
		action->cr16_hist[action->cr16_idx++] = (int) cr_start;
		action->cr16_idx &= PARISC_CR16_HIST_SIZE - 1;
#endif
	}

	irq_exit(cpu, irq);
}


/* ONLY called from entry.S:intr_extint() */
void do_cpu_irq_mask(struct pt_regs *regs)