/*
* linux/arch/m68k/hp300/ints.c
*
* Copyright (C) 1998 Philip Blundell <philb@gnu.org>
*
* This file contains the HP300-specific interrupt handling.
* We only use the autovector interrupts, and therefore we need to
* maintain lists of devices sharing each ipl.
* [ipl list code added by Peter Maydell <pmaydell@chiark.greenend.org.uk> 06/1998]
*/
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/kernel_stat.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <asm/machdep.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/traps.h>
#include <asm/ptrace.h>
#include <asm/errno.h>
#include "ints.h"
/* Each ipl has a linked list of interrupt service routines.
* Service routines are added via hp300_request_irq() and removed
* via hp300_free_irq(). The device driver should set IRQ_FLG_FAST
* if it needs to be serviced early (eg FIFOless UARTs); this will
* cause it to be added at the front of the queue rather than
* the back.
* Currently IRQ_FLG_SLOW and flags=0 are treated identically; if
* we needed three levels of priority we could distinguish them
* but this strikes me as mildly ugly...
*/
/* we start with no entries in any list */
static irq_node_t *hp300_irq_list[HP300_NUM_IRQS];
static spinlock_t irqlist_lock;
/* This handler receives all interrupts, dispatching them to the registered handlers */
static irqreturn_t hp300_int_handler(int irq, void *dev_id, struct pt_regs *fp)
{
irq_node_t *t;
/* We just give every handler on the chain an opportunity to handle
* the interrupt, in priority order.
*/
for(t = hp300_irq_list[irq]; t; t=t->next)
t->handler(irq, t->dev_id, fp);
/* We could put in some accounting routines, checks for stray interrupts,
* etc, in here. Note that currently we can't tell whether or not
* a handler handles the interrupt, though.
*/
return IRQ_HANDLED;
}
static irqreturn_t hp300_badint(int irq, void *dev_id, struct pt_regs *fp)
{
num_spurious += 1;
return IRQ_NONE;
}
irqreturn_t (*hp300_default_handler[SYS_IRQS])(int, void *, struct pt_regs *) = {
[0] = hp300_badint,
[1] = hp300_int_handler,
[2] = hp300_int_handler,
[3] = hp300_int_handler,
[4] = hp300_int_handler,
[5] = hp300_int_handler,
[6] = hp300_int_handler,
[7] = hp300_int_handler
};
/* dev_id had better be unique to each handler because it's the only way we have
* to distinguish handlers when removing them...
*
* It would be pretty easy to support IRQ_FLG_LOCK (handler is not replacable)
* and IRQ_FLG_REPLACE (handler replaces existing one with this dev_id)
* if we wanted to. IRQ_FLG_FAST is needed for devices where interrupt latency
* matters (eg the dreaded FIFOless UART...)
*/
int hp300_request_irq(unsigned int irq,
irqreturn_t (*handler) (int, void *, struct pt_regs *),
unsigned long flags, const char *devname, void *dev_id)
{
irq_node_t *t, *n = new_irq_node();
if (!n) /* oops, no free nodes */
return -ENOMEM;
spin_lock_irqsave(&irqlist_lock, flags);
if (!hp300_irq_list[irq]) {
/* no list yet */
hp300_irq_list[irq] = n;
n->next = NULL;
} else if (flags & IRQ_FLG_FAST) {
/* insert at head of list */
n->next = hp300_irq_list[irq];
hp300_irq_list[irq] = n;
} else {
/* insert at end of list */
for(t = hp300_irq_list[irq]; t->next; t = t->next)
/* do nothing */;
n->next = NULL;
t->next = n;
}
/* Fill in n appropriately */
n->handler = handler;
n->flags = flags;
n->dev_id = dev_id;
n->devname = devname;
spin_unlock_irqrestore(&irqlist_lock, flags);
return 0;
}
void hp300_free_irq(unsigned int irq, void *dev_id)
{
irq_node_t *t;
unsigned long flags;
spin_lock_irqsave(&irqlist_lock, flags);
t = hp300_irq_list[irq];
if (!t) /* no handlers at all for that IRQ */
{
printk(KERN_ERR "hp300_free_irq: attempt to remove nonexistent handler for IRQ %d\n", irq);
spin_unlock_irqrestore(&irqlist_lock, flags);
return;
}
if (t->dev_id == dev_id)
{ /* removing first handler on chain */
t->flags = IRQ_FLG_STD; /* we probably don't really need these */
t->dev_id = NULL;
t->devname = NULL;
t->handler = NULL; /* frees this irq_node_t */
hp300_irq_list[irq] = t->next;
spin_unlock_irqrestore(&irqlist_lock, flags);
return;
}
/* OK, must be removing from middle of the chain */
for (t = hp300_irq_list[irq]; t->next && t->next->dev_id != dev_id; t = t->next)
/* do nothing */;
if (!t->next)
{
printk(KERN_ERR "hp300_free_irq: attempt to remove nonexistent handler for IRQ %d\n", irq);
spin_unlock_irqrestore(&irqlist_lock, flags);
return;
}
/* remove the entry after t: */
t->next->flags = IRQ_FLG_STD;
t->next->dev_id = NULL;
t->next->devname = NULL;
t->next->handler = NULL;
t->next = t->next->next;
spin_unlock_irqrestore(&irqlist_lock, flags);
}
int show_hp300_interrupts(struct seq_file *p, void *v)
{
return 0;
}
void __init hp300_init_IRQ(void)
{
spin_lock_init(&irqlist_lock);
}
