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/*
* linux/arch/mips/dec/kn02-irq.c
*
* DECstation 5000/200 (KN02) Control and Status Register
* interrupts.
*
* Copyright (c) 2002, 2003, 2005 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;
DEFINE_SPINLOCK(kn02_lock);
static int kn02_irq_base;
static inline void unmask_kn02_irq(unsigned int irq)
{
volatile u32 *csr = (volatile u32 *)CKSEG1ADDR(KN02_SLOT_BASE +
KN02_CSR);
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 *)CKSEG1ADDR(KN02_SLOT_BASE +
KN02_CSR);
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);
}
static struct irq_chip kn02_irq_type = {
.typename = "KN02-CSR",
.startup = startup_kn02_irq,
.shutdown = shutdown_kn02_irq,
.enable = enable_kn02_irq,
.disable = disable_kn02_irq,
.ack = ack_kn02_irq,
.end = end_kn02_irq,
};
void __init init_kn02_irqs(int base)
{
volatile u32 *csr = (volatile u32 *)CKSEG1ADDR(KN02_SLOT_BASE +
KN02_CSR);
unsigned long flags;
int i;
/* Mask interrupts. */
spin_lock_irqsave(&kn02_lock, flags);
cached_kn02_csr &= ~KN02_CSR_IOINTEN;
*csr = cached_kn02_csr;
iob();
spin_unlock_irqrestore(&kn02_lock, flags);
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].chip = &kn02_irq_type;
}
kn02_irq_base = base;
}
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