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// SPDX-License-Identifier: GPL-2.0
/*
* linux/arch/alpha/kernel/irq_pyxis.c
*
* Based on code written by David A Rusling (david.rusling@reo.mts.dec.com).
*
* IRQ Code common to all PYXIS core logic chips.
*/
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/irq.h>
#include <asm/io.h>
#include <asm/core_cia.h>
#include "proto.h"
#include "irq_impl.h"
/* Note mask bit is true for ENABLED irqs. */
static unsigned long cached_irq_mask;
static inline void
pyxis_update_irq_hw(unsigned long mask)
{
*(vulp)PYXIS_INT_MASK = mask;
mb();
*(vulp)PYXIS_INT_MASK;
}
static inline void
pyxis_enable_irq(struct irq_data *d)
{
pyxis_update_irq_hw(cached_irq_mask |= 1UL << (d->irq - 16));
}
static void
pyxis_disable_irq(struct irq_data *d)
{
pyxis_update_irq_hw(cached_irq_mask &= ~(1UL << (d->irq - 16)));
}
static void
pyxis_mask_and_ack_irq(struct irq_data *d)
{
unsigned long bit = 1UL << (d->irq - 16);
unsigned long mask = cached_irq_mask &= ~bit;
/* Disable the interrupt. */
*(vulp)PYXIS_INT_MASK = mask;
wmb();
/* Ack PYXIS PCI interrupt. */
*(vulp)PYXIS_INT_REQ = bit;
mb();
/* Re-read to force both writes. */
*(vulp)PYXIS_INT_MASK;
}
static struct irq_chip pyxis_irq_type = {
.name = "PYXIS",
.irq_mask_ack = pyxis_mask_and_ack_irq,
.irq_mask = pyxis_disable_irq,
.irq_unmask = pyxis_enable_irq,
};
void
pyxis_device_interrupt(unsigned long vector)
{
unsigned long pld;
unsigned int i;
/* Read the interrupt summary register of PYXIS */
pld = *(vulp)PYXIS_INT_REQ;
pld &= cached_irq_mask;
/*
* Now for every possible bit set, work through them and call
* the appropriate interrupt handler.
*/
while (pld) {
i = ffz(~pld);
pld &= pld - 1; /* clear least bit set */
if (i == 7)
isa_device_interrupt(vector);
else
handle_irq(16+i);
}
}
void __init
init_pyxis_irqs(unsigned long ignore_mask)
{
long i;
*(vulp)PYXIS_INT_MASK = 0; /* disable all */
*(vulp)PYXIS_INT_REQ = -1; /* flush all */
mb();
/* Send -INTA pulses to clear any pending interrupts ...*/
*(vuip) CIA_IACK_SC;
for (i = 16; i < 48; ++i) {
if ((ignore_mask >> i) & 1)
continue;
irq_set_chip_and_handler(i, &pyxis_irq_type, handle_level_irq);
irq_set_status_flags(i, IRQ_LEVEL);
}
if (request_irq(16 + 7, no_action, 0, "isa-cascade", NULL))
pr_err("Failed to register isa-cascade interrupt\n");
}
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