Linux/Unix编程

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Unix_Linux

kn02-irq.c：源码内容

							/*
 *	linux/arch/mips/dec/kn02-irq.c
 *
 *	DECstation 5000/200 (KN02) Control and Status Register
 *	interrupts.
 *
 *	Copyright (c) 2002  Maciej W. Rozycki
 *
 *	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.
 */
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <asm/dec/kn02.h>
/*
 * Bits 7:0 of the Control Register are write-only -- the
 * corresponding bits of the Status Register have a different
 * meaning.  Hence we use a cache.  It speeds up things a bit
 * as well.
 *
 * There is no default value -- it has to be initialized.
 */
u32 cached_kn02_csr;
spinlock_t kn02_lock = SPIN_LOCK_UNLOCKED;
static int kn02_irq_base;
static inline void unmask_kn02_irq(unsigned int irq)
{
	volatile u32 *csr = (volatile u32 *)KN02_CSR_ADDR;
	cached_kn02_csr |= (1 << (irq - kn02_irq_base + 16));
	*csr = cached_kn02_csr;
}
static inline void mask_kn02_irq(unsigned int irq)
{
	volatile u32 *csr = (volatile u32 *)KN02_CSR_ADDR;
	cached_kn02_csr &= ~(1 << (irq - kn02_irq_base + 16));
	*csr = cached_kn02_csr;
}
static inline void enable_kn02_irq(unsigned int irq)
{
	unsigned long flags;
	spin_lock_irqsave(&kn02_lock, flags);
	unmask_kn02_irq(irq);
	spin_unlock_irqrestore(&kn02_lock, flags);
}
static inline void disable_kn02_irq(unsigned int irq)
{
	unsigned long flags;
	spin_lock_irqsave(&kn02_lock, flags);
	mask_kn02_irq(irq);
	spin_unlock_irqrestore(&kn02_lock, flags);
}
static unsigned int startup_kn02_irq(unsigned int irq)
{
	enable_kn02_irq(irq);
	return 0;
}
#define shutdown_kn02_irq disable_kn02_irq
static void ack_kn02_irq(unsigned int irq)
{
	spin_lock(&kn02_lock);
	mask_kn02_irq(irq);
	spin_unlock(&kn02_lock);
	iob();
}
static void end_kn02_irq(unsigned int irq)
{
	if (!(irq_desc[irq].status & (IRQ_DISABLED | IRQ_INPROGRESS)))
		enable_kn02_irq(irq);
}
#define set_kn02_affinity NULL
static struct hw_interrupt_type kn02_irq_type = {
	"KN02-CSR",
	startup_kn02_irq,
	shutdown_kn02_irq,
	enable_kn02_irq,
	disable_kn02_irq,
	ack_kn02_irq,
	end_kn02_irq,
	set_kn02_affinity,
};
void __init init_kn02_irqs(int base)
{
	volatile u32 *csr = (volatile u32 *)KN02_CSR_ADDR;
	int i;
	/* Mask interrupts and preset write-only bits. */
	cached_kn02_csr = (*csr & ~0xff0000) | 0xff;
	*csr = cached_kn02_csr;
	iob();
	for (i = base; i < base + KN02_IRQ_LINES; i++) {
		irq_desc[i].status = IRQ_DISABLED;
		irq_desc[i].action = 0;
		irq_desc[i].depth = 1;
		irq_desc[i].handler = &kn02_irq_type;
	}
	kn02_irq_base = base;
}

						