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/* $Id: irq.c,v 1.21 2001/07/17 02:26:53 gniibe Exp $
*
* linux/arch/sh/kernel/irq.c
*
* Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
*
*
* SuperH version: Copyright (C) 1999 Niibe Yutaka
*/
/*
* IRQs are in fact implemented a bit like signal handlers for the kernel.
* Naturally it's not a 1:1 relation, but there are similarities.
*/
#include <linux/config.h>
#include <linux/ptrace.h>
#include <linux/errno.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/timex.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/bitops.h>
#include <asm/pgalloc.h>
#include <asm/delay.h>
#include <asm/irq.h>
#include <linux/irq.h>
/*
* Controller mappings for all interrupt sources:
*/
irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned =
{ [0 ... NR_IRQS-1] = { 0, &no_irq_type, }};
/*
* Special irq handlers.
*/
void no_action(int cpl, void *dev_id, struct pt_regs *regs) { }
/*
* Generic no controller code
*/
static void enable_none(unsigned int irq) { }
static unsigned int startup_none(unsigned int irq) { return 0; }
static void disable_none(unsigned int irq) { }
static void ack_none(unsigned int irq)
{
/*
* 'what should we do if we get a hw irq event on an illegal vector'.
* each architecture has to answer this themselves, it doesnt deserve
* a generic callback i think.
*/
printk("unexpected IRQ trap at vector %02x\n", irq);
}
/* startup is the same as "enable", shutdown is same as "disable" */
#define shutdown_none disable_none
#define end_none enable_none
struct hw_interrupt_type no_irq_type = {
"none",
startup_none,
shutdown_none,
enable_none,
disable_none,
ack_none,
end_none
};
/*
* Generic, controller-independent functions:
*/
#if defined(CONFIG_PROC_FS)
int get_irq_list(char *buf)
{
int i, j;
struct irqaction * action;
char *p = buf;
p += sprintf(p, " ");
for (j=0; j<smp_num_cpus; j++)
p += sprintf(p, "CPU%d ",j);
*p++ = '\n';
for (i = 0 ; i < ACTUAL_NR_IRQS ; i++) {
action = irq_desc[i].action;
if (!action)
continue;
p += sprintf(p, "%3d: ",i);
p += sprintf(p, "%10u ", kstat_irqs(i));
p += sprintf(p, " %14s", irq_desc[i].handler->typename);
p += sprintf(p, " %s", action->name);
for (action=action->next; action; action = action->next)
p += sprintf(p, ", %s", action->name);
*p++ = '\n';
}
return p - buf;
}
#endif
/*
* This should really return information about whether
* we should do bottom half handling etc. Right now we
* end up _always_ checking the bottom half, which is a
* waste of time and is not what some drivers would
* prefer.
*/
int handle_IRQ_event(unsigned int irq, struct pt_regs * regs, struct irqaction * action)
{
int status;
int cpu = smp_processor_id();
irq_enter(cpu, irq);
status = 1; /* Force the "do bottom halves" bit */
if (!(action->flags & SA_INTERRUPT))
__sti();
do {
status |= action->flags;
action->handler(irq, action->dev_id, regs);
action = action->next;
} while (action);
if (status & SA_SAMPLE_RANDOM)
add_interrupt_randomness(irq);
__cli();
irq_exit(cpu, irq);
return status;
}
/*
* Generic enable/disable code: this just calls
* down into the PIC-specific version for the actual
* hardware disable after having gotten the irq
* controller lock.
*/
void disable_irq_nosync(unsigned int irq)
{
irq_desc_t *desc = irq_desc + irq;
unsigned long flags;
spin_lock_irqsave(&desc->lock, flags);
if (!desc->depth++) {
desc->status |= IRQ_DISABLED;
desc->handler->disable(irq);
}
spin_unlock_irqrestore(&desc->lock, flags);
}
/*
* Synchronous version of the above, making sure the IRQ is
* no longer running on any other IRQ..
*/
void disable_irq(unsigned int irq)
{
disable_irq_nosync(irq);
if (!local_irq_count(smp_processor_id())) {
do {
barrier();
} while (irq_desc[irq].status & IRQ_INPROGRESS);
}
}
void enable_irq(unsigned int irq)
{
irq_desc_t *desc = irq_desc + irq;
unsigned long flags;
spin_lock_irqsave(&desc->lock, flags);
switch (desc->depth) {
case 1: {
unsigned int status = desc->status & ~IRQ_DISABLED;
desc->status = status;
if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
desc->status = status | IRQ_REPLAY;
hw_resend_irq(desc->handler,irq);
}
desc->handler->enable(irq);
/* fall-through */
}
default:
desc->depth--;
break;
case 0:
printk("enable_irq() unbalanced from %p\n",
__builtin_return_address(0));
}
spin_unlock_irqrestore(&desc->lock, flags);
}
/*
* do_IRQ handles all normal device IRQ's.
*/
asmlinkage int do_IRQ(unsigned long r4, unsigned long r5,
unsigned long r6, unsigned long r7,
struct pt_regs regs)
{
/*
* We ack quickly, we don't want the irq controller
* thinking we're snobs just because some other CPU has
* disabled global interrupts (we have already done the
* INT_ACK cycles, it's too late to try to pretend to the
* controller that we aren't taking the interrupt).
*
* 0 return value means that this irq is already being
* handled by some other CPU. (or is disabled)
*/
int irq;
int cpu = smp_processor_id();
irq_desc_t *desc;
struct irqaction * action;
unsigned int status;
/* Get IRQ number */
asm volatile("stc r2_bank, %0\n\t"
"shlr2 %0\n\t"
"shlr2 %0\n\t"
"shlr %0\n\t"
"add #-16, %0\n\t"
:"=z" (irq));
irq = irq_demux(irq);
kstat.irqs[cpu][irq]++;
desc = irq_desc + irq;
spin_lock(&desc->lock);
desc->handler->ack(irq);
/*
REPLAY is when Linux resends an IRQ that was dropped earlier
WAITING is used by probe to mark irqs that are being tested
*/
status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
status |= IRQ_PENDING; /* we _want_ to handle it */
/*
* If the IRQ is disabled for whatever reason, we cannot
* use the action we have.
*/
action = NULL;
if (!(status & (IRQ_DISABLED | IRQ_INPROGRESS))) {
action = desc->action;
status &= ~IRQ_PENDING; /* we commit to handling */
status |= IRQ_INPROGRESS; /* we are handling it */
}
desc->status = status;
/*
* If there is no IRQ handler or it was disabled, exit early.
Since we set PENDING, if another processor is handling
a different instance of this same irq, the other processor
will take care of it.
*/
if (!action)
goto out;
/*
* Edge triggered interrupts need to remember
* pending events.
* This applies to any hw interrupts that allow a second
* instance of the same irq to arrive while we are in do_IRQ
* or in the handler. But the code here only handles the _second_
* instance of the irq, not the third or fourth. So it is mostly
* useful for irq hardware that does not mask cleanly in an
* SMP environment.
*/
for (;;) {
spin_unlock(&desc->lock);
handle_IRQ_event(irq, ®s, action);
spin_lock(&desc->lock);
if (!(desc->status & IRQ_PENDING))
break;
desc->status &= ~IRQ_PENDING;
}
desc->status &= ~IRQ_INPROGRESS;
out:
/*
* The ->end() handler has to deal with interrupts which got
* disabled while the handler was running.
*/
desc->handler->end(irq);
spin_unlock(&desc->lock);
if (softirq_pending(cpu))
do_softirq();
return 1;
}
int request_irq(unsigned int irq,
void (*handler)(int, void *, struct pt_regs *),
unsigned long irqflags,
const char * devname,
void *dev_id)
{
int retval;
struct irqaction * action;
if (irq >= ACTUAL_NR_IRQS)
return -EINVAL;
if (!handler)
return -EINVAL;
action = (struct irqaction *)
kmalloc(sizeof(struct irqaction), GFP_KERNEL);
if (!action)
return -ENOMEM;
action->handler = handler;
action->flags = irqflags;
action->mask = 0;
action->name = devname;
action->next = NULL;
action->dev_id = dev_id;
retval = setup_irq(irq, action);
if (retval)
kfree(action);
return retval;
}
void free_irq(unsigned int irq, void *dev_id)
{
irq_desc_t *desc;
struct irqaction **p;
unsigned long flags;
if (irq >= ACTUAL_NR_IRQS)
return;
desc = irq_desc + irq;
spin_lock_irqsave(&desc->lock,flags);
p = &desc->action;
for (;;) {
struct irqaction * action = *p;
if (action) {
struct irqaction **pp = p;
p = &action->next;
if (action->dev_id != dev_id)
continue;
/* Found it - now remove it from the list of entries */
*pp = action->next;
if (!desc->action) {
desc->status |= IRQ_DISABLED;
desc->handler->shutdown(irq);
}
spin_unlock_irqrestore(&desc->lock,flags);
kfree(action);
return;
}
printk("Trying to free free IRQ%d\n",irq);
spin_unlock_irqrestore(&desc->lock,flags);
return;
}
}
static DECLARE_MUTEX(probe_sem);
/*
* IRQ autodetection code..
*
* This depends on the fact that any interrupt that
* comes in on to an unassigned handler will get stuck
* with "IRQ_WAITING" cleared and the interrupt
* disabled.
*/
unsigned long probe_irq_on(void)
{
unsigned int i;
irq_desc_t *desc;
unsigned long val;
unsigned long delay;
down(&probe_sem);
/*
* something may have generated an irq long ago and we want to
* flush such a longstanding irq before considering it as spurious.
*/
for (i = NR_IRQS-1; i > 0; i--) {
desc = irq_desc + i;
spin_lock_irq(&desc->lock);
if (!desc->action)
desc->handler->startup(i);
spin_unlock_irq(&desc->lock);
}
/* Wait for longstanding interrupts to trigger. */
for (delay = jiffies + HZ/50; time_after(delay, jiffies); )
/* about 20ms delay */ synchronize_irq();
/*
* enable any unassigned irqs
* (we must startup again here because if a longstanding irq
* happened in the previous stage, it may have masked itself)
*/
for (i = NR_IRQS-1; i > 0; i--) {
desc = irq_desc + i;
spin_lock_irq(&desc->lock);
if (!desc->action) {
desc->status |= IRQ_AUTODETECT | IRQ_WAITING;
if (desc->handler->startup(i))
desc->status |= IRQ_PENDING;
}
spin_unlock_irq(&desc->lock);
}
/*
* Wait for spurious interrupts to trigger
*/
for (delay = jiffies + HZ/10; time_after(delay, jiffies); )
/* about 100ms delay */ synchronize_irq();
/*
* Now filter out any obviously spurious interrupts
*/
val = 0;
for (i=0; i<NR_IRQS; i++) {
desc = irq_desc + i;
unsigned int status;
spin_lock_irq(&desc->lock);
status = desc->status;
if (status & IRQ_AUTODETECT) {
/* It triggered already - consider it spurious. */
if (!(status & IRQ_WAITING)) {
desc->status = status & ~IRQ_AUTODETECT;
desc->handler->shutdown(i);
} else
if (i < 32)
val |= 1 << i;
}
spin_unlock_irq(&desc->lock);
}
return val;
}
int probe_irq_off(unsigned long val)
{
int i, irq_found, nr_irqs;
nr_irqs = 0;
irq_found = 0;
for (i=0; i<NR_IRQS; i++) {
irq_desc_t *desc = irq_desc + i;
unsigned int status;
spin_lock_irq(&desc->lock);
status = desc->status;
if (status & IRQ_AUTODETECT) {
if (!(status & IRQ_WAITING)) {
if (!nr_irqs)
irq_found = i;
nr_irqs++;
}
desc->status = status & ~IRQ_AUTODETECT;
desc->handler->shutdown(i);
}
spin_unlock_irq(&desc->lock);
}
up(&probe_sem);
if (nr_irqs > 1)
irq_found = -irq_found;
return irq_found;
}
int setup_irq(unsigned int irq, struct irqaction * new)
{
int shared = 0;
struct irqaction *old, **p;
unsigned long flags;
irq_desc_t *desc = irq_desc + irq;
/*
* Some drivers like serial.c use request_irq() heavily,
* so we have to be careful not to interfere with a
* running system.
*/
if (new->flags & SA_SAMPLE_RANDOM) {
/*
* This function might sleep, we want to call it first,
* outside of the atomic block.
* Yes, this might clear the entropy pool if the wrong
* driver is attempted to be loaded, without actually
* installing a new handler, but is this really a problem,
* only the sysadmin is able to do this.
*/
rand_initialize_irq(irq);
}
/*
* The following block of code has to be executed atomically
*/
spin_lock_irqsave(&desc->lock,flags);
p = &desc->action;
if ((old = *p) != NULL) {
/* Can't share interrupts unless both agree to */
if (!(old->flags & new->flags & SA_SHIRQ)) {
spin_unlock_irqrestore(&desc->lock,flags);
return -EBUSY;
}
/* add new interrupt at end of irq queue */
do {
p = &old->next;
old = *p;
} while (old);
shared = 1;
}
*p = new;
if (!shared) {
desc->depth = 0;
desc->status &= ~(IRQ_DISABLED | IRQ_AUTODETECT | IRQ_WAITING);
desc->handler->startup(irq);
}
spin_unlock_irqrestore(&desc->lock,flags);
return 0;
}
#if defined(CONFIG_PROC_FS) && defined(CONFIG_SYSCTL)
void init_irq_proc(void)
{
}
#endif
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