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/* MN10300 Arch-specific interrupt handling
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/seq_file.h>
#include <asm/setup.h>
unsigned long __mn10300_irq_enabled_epsw = EPSW_IE | EPSW_IM_7;
EXPORT_SYMBOL(__mn10300_irq_enabled_epsw);
atomic_t irq_err_count;
/*
* MN10300 interrupt controller operations
*/
static void mn10300_cpupic_ack(unsigned int irq)
{
u16 tmp;
*(volatile u8 *) &GxICR(irq) = GxICR_DETECT;
tmp = GxICR(irq);
}
static void mn10300_cpupic_mask(unsigned int irq)
{
u16 tmp = GxICR(irq);
GxICR(irq) = (tmp & GxICR_LEVEL);
tmp = GxICR(irq);
}
static void mn10300_cpupic_mask_ack(unsigned int irq)
{
u16 tmp = GxICR(irq);
GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_DETECT;
tmp = GxICR(irq);
}
static void mn10300_cpupic_unmask(unsigned int irq)
{
u16 tmp = GxICR(irq);
GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_ENABLE;
tmp = GxICR(irq);
}
static void mn10300_cpupic_unmask_clear(unsigned int irq)
{
/* the MN10300 PIC latches its interrupt request bit, even after the
* device has ceased to assert its interrupt line and the interrupt
* channel has been disabled in the PIC, so for level-triggered
* interrupts we need to clear the request bit when we re-enable */
u16 tmp = GxICR(irq);
GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_ENABLE | GxICR_DETECT;
tmp = GxICR(irq);
}
/*
* MN10300 PIC level-triggered IRQ handling.
*
* The PIC has no 'ACK' function per se. It is possible to clear individual
* channel latches, but each latch relatches whether or not the channel is
* masked, so we need to clear the latch when we unmask the channel.
*
* Also for this reason, we don't supply an ack() op (it's unused anyway if
* mask_ack() is provided), and mask_ack() just masks.
*/
static struct irq_chip mn10300_cpu_pic_level = {
.name = "cpu_l",
.disable = mn10300_cpupic_mask,
.enable = mn10300_cpupic_unmask_clear,
.ack = NULL,
.mask = mn10300_cpupic_mask,
.mask_ack = mn10300_cpupic_mask,
.unmask = mn10300_cpupic_unmask_clear,
};
/*
* MN10300 PIC edge-triggered IRQ handling.
*
* We use the latch clearing function of the PIC as the 'ACK' function.
*/
static struct irq_chip mn10300_cpu_pic_edge = {
.name = "cpu_e",
.disable = mn10300_cpupic_mask,
.enable = mn10300_cpupic_unmask,
.ack = mn10300_cpupic_ack,
.mask = mn10300_cpupic_mask,
.mask_ack = mn10300_cpupic_mask_ack,
.unmask = mn10300_cpupic_unmask,
};
/*
* 'what should we do if we get a hw irq event on an illegal vector'.
* each architecture has to answer this themselves.
*/
void ack_bad_irq(int irq)
{
printk(KERN_WARNING "unexpected IRQ trap at vector %02x\n", irq);
}
/*
* change the level at which an IRQ executes
* - must not be called whilst interrupts are being processed!
*/
void set_intr_level(int irq, u16 level)
{
u16 tmp;
if (in_interrupt())
BUG();
tmp = GxICR(irq);
GxICR(irq) = (tmp & GxICR_ENABLE) | level;
tmp = GxICR(irq);
}
/*
* mark an interrupt to be ACK'd after interrupt handlers have been run rather
* than before
* - see Documentation/mn10300/features.txt
*/
void set_intr_postackable(int irq)
{
set_irq_chip_and_handler(irq, &mn10300_cpu_pic_level,
handle_level_irq);
}
/*
* initialise the interrupt system
*/
void __init init_IRQ(void)
{
int irq;
for (irq = 0; irq < NR_IRQS; irq++)
if (irq_desc[irq].chip == &no_irq_chip)
/* due to the PIC latching interrupt requests, even
* when the IRQ is disabled, IRQ_PENDING is superfluous
* and we can use handle_level_irq() for edge-triggered
* interrupts */
set_irq_chip_and_handler(irq, &mn10300_cpu_pic_edge,
handle_level_irq);
unit_init_IRQ();
}
/*
* handle normal device IRQs
*/
asmlinkage void do_IRQ(void)
{
unsigned long sp, epsw, irq_disabled_epsw, old_irq_enabled_epsw;
int irq;
sp = current_stack_pointer();
if (sp - (sp & ~(THREAD_SIZE - 1)) < STACK_WARN)
BUG();
/* make sure local_irq_enable() doesn't muck up the interrupt priority
* setting in EPSW */
old_irq_enabled_epsw = __mn10300_irq_enabled_epsw;
local_save_flags(epsw);
__mn10300_irq_enabled_epsw = EPSW_IE | (EPSW_IM & epsw);
irq_disabled_epsw = EPSW_IE | MN10300_CLI_LEVEL;
__IRQ_STAT(smp_processor_id(), __irq_count)++;
irq_enter();
for (;;) {
/* ask the interrupt controller for the next IRQ to process
* - the result we get depends on EPSW.IM
*/
irq = IAGR & IAGR_GN;
if (!irq)
break;
local_irq_restore(irq_disabled_epsw);
generic_handle_irq(irq >> 2);
/* restore IRQ controls for IAGR access */
local_irq_restore(epsw);
}
__mn10300_irq_enabled_epsw = old_irq_enabled_epsw;
irq_exit();
}
/*
* Display interrupt management information through /proc/interrupts
*/
int show_interrupts(struct seq_file *p, void *v)
{
int i = *(loff_t *) v, j, cpu;
struct irqaction *action;
unsigned long flags;
switch (i) {
/* display column title bar naming CPUs */
case 0:
seq_printf(p, " ");
for (j = 0; j < NR_CPUS; j++)
if (cpu_online(j))
seq_printf(p, "CPU%d ", j);
seq_putc(p, '\n');
break;
/* display information rows, one per active CPU */
case 1 ... NR_IRQS - 1:
spin_lock_irqsave(&irq_desc[i].lock, flags);
action = irq_desc[i].action;
if (action) {
seq_printf(p, "%3d: ", i);
for_each_present_cpu(cpu)
seq_printf(p, "%10u ", kstat_irqs_cpu(i, cpu));
seq_printf(p, " %14s.%u", irq_desc[i].chip->name,
(GxICR(i) & GxICR_LEVEL) >>
GxICR_LEVEL_SHIFT);
seq_printf(p, " %s", action->name);
for (action = action->next;
action;
action = action->next)
seq_printf(p, ", %s", action->name);
seq_putc(p, '\n');
}
spin_unlock_irqrestore(&irq_desc[i].lock, flags);
break;
/* polish off with NMI and error counters */
case NR_IRQS:
seq_printf(p, "NMI: ");
for (j = 0; j < NR_CPUS; j++)
if (cpu_online(j))
seq_printf(p, "%10u ", nmi_count(j));
seq_putc(p, '\n');
seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
break;
}
return 0;
}
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