kn02-irq.c
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/*
* 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/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;
static int kn02_irq_base;
static void unmask_kn02_irq(struct irq_data *d)
{
volatile u32 *csr = (volatile u32 *)CKSEG1ADDR(KN02_SLOT_BASE +
KN02_CSR);
cached_kn02_csr |= (1 << (d->irq - kn02_irq_base + 16));
*csr = cached_kn02_csr;
}
static void mask_kn02_irq(struct irq_data *d)
{
volatile u32 *csr = (volatile u32 *)CKSEG1ADDR(KN02_SLOT_BASE +
KN02_CSR);
cached_kn02_csr &= ~(1 << (d->irq - kn02_irq_base + 16));
*csr = cached_kn02_csr;
}
static void ack_kn02_irq(struct irq_data *d)
{
mask_kn02_irq(d);
iob();
}
static struct irq_chip kn02_irq_type = {
.name = "KN02-CSR",
.irq_ack = ack_kn02_irq,
.irq_mask = mask_kn02_irq,
.irq_mask_ack = ack_kn02_irq,
.irq_unmask = unmask_kn02_irq,
};
void __init init_kn02_irqs(int base)
{
volatile u32 *csr = (volatile u32 *)CKSEG1ADDR(KN02_SLOT_BASE +
KN02_CSR);
int i;
/* Mask interrupts. */
cached_kn02_csr &= ~KN02_CSR_IOINTEN;
*csr = cached_kn02_csr;
iob();
for (i = base; i < base + KN02_IRQ_LINES; i++)
irq_set_chip_and_handler(i, &kn02_irq_type, handle_level_irq);
kn02_irq_base = base;
}