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/*
* linux/arch/alpha/kernel/irq.c
*
* Copyright (C) 1995 Linus Torvalds
*
* This file contains the code used by various IRQ handling routines:
* asking for different IRQ's should be done through these routines
* instead of just grabbing them. Thus setups with different IRQ numbers
* shouldn't result in any weird surprises, and installing new handlers
* should be easier.
*/
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/ptrace.h>
#include <linux/errno.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/proc_fs.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/bitops.h>
#include <asm/uaccess.h>
/*
* Controller mappings for all interrupt sources:
*/
irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {
[0 ... NR_IRQS-1] = { 0, &no_irq_type, NULL, 0, SPIN_LOCK_UNLOCKED}
};
static void register_irq_proc(unsigned int irq);
volatile unsigned long irq_err_count;
/*
* Special irq handlers.
*/
void no_action(int cpl, void *dev_id, struct pt_regs *regs) { }
/*
* Generic no controller code
*/
static void no_irq_enable_disable(unsigned int irq) { }
static unsigned int no_irq_startup(unsigned int irq) { return 0; }
static void
no_irq_ack(unsigned int irq)
{
irq_err_count++;
printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
}
struct hw_interrupt_type no_irq_type = {
typename: "none",
startup: no_irq_startup,
shutdown: no_irq_enable_disable,
enable: no_irq_enable_disable,
disable: no_irq_enable_disable,
ack: no_irq_ack,
end: no_irq_enable_disable,
};
int
handle_IRQ_event(unsigned int irq, struct pt_regs *regs,
struct irqaction *action)
{
int status;
int cpu = smp_processor_id();
kstat.irqs[cpu][irq]++;
irq_enter(cpu, irq);
status = 1; /* Force the "do bottom halves" bit */
do {
if (!(action->flags & SA_INTERRUPT))
__sti();
else
__cli();
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 inline
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(KERN_ERR "enable_irq() unbalanced from %p\n",
__builtin_return_address(0));
}
spin_unlock_irqrestore(&desc->lock, flags);
}
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;
desc->handler->startup(irq);
}
spin_unlock_irqrestore(&desc->lock,flags);
return 0;
}
static struct proc_dir_entry * root_irq_dir;
static struct proc_dir_entry * irq_dir[NR_IRQS];
#ifdef CONFIG_SMP
static struct proc_dir_entry * smp_affinity_entry[NR_IRQS];
static char irq_user_affinity[NR_IRQS];
static unsigned long irq_affinity[NR_IRQS] = { [0 ... NR_IRQS-1] = ~0UL };
static void
select_smp_affinity(int irq)
{
static int last_cpu;
int cpu = last_cpu + 1;
if (! irq_desc[irq].handler->set_affinity || irq_user_affinity[irq])
return;
while (((cpu_present_mask >> cpu) & 1) == 0)
cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
last_cpu = cpu;
irq_affinity[irq] = 1UL << cpu;
irq_desc[irq].handler->set_affinity(irq, 1UL << cpu);
}
#define HEX_DIGITS 16
static int
irq_affinity_read_proc (char *page, char **start, off_t off,
int count, int *eof, void *data)
{
if (count < HEX_DIGITS+1)
return -EINVAL;
return sprintf (page, "%016lx\n", irq_affinity[(long)data]);
}
static unsigned int
parse_hex_value (const char *buffer,
unsigned long count, unsigned long *ret)
{
unsigned char hexnum [HEX_DIGITS];
unsigned long value;
int i;
if (!count)
return -EINVAL;
if (count > HEX_DIGITS)
count = HEX_DIGITS;
if (copy_from_user(hexnum, buffer, count))
return -EFAULT;
/*
* Parse the first 8 characters as a hex string, any non-hex char
* is end-of-string. '00e1', 'e1', '00E1', 'E1' are all the same.
*/
value = 0;
for (i = 0; i < count; i++) {
unsigned int c = hexnum[i];
switch (c) {
case '0' ... '9': c -= '0'; break;
case 'a' ... 'f': c -= 'a'-10; break;
case 'A' ... 'F': c -= 'A'-10; break;
default:
goto out;
}
value = (value << 4) | c;
}
out:
*ret = value;
return 0;
}
static int
irq_affinity_write_proc(struct file *file, const char *buffer,
unsigned long count, void *data)
{
int irq = (long) data, full_count = count, err;
unsigned long new_value;
if (!irq_desc[irq].handler->set_affinity)
return -EIO;
err = parse_hex_value(buffer, count, &new_value);
/* The special value 0 means release control of the
affinity to kernel. */
if (new_value == 0) {
irq_user_affinity[irq] = 0;
select_smp_affinity(irq);
}
/* Do not allow disabling IRQs completely - it's a too easy
way to make the system unusable accidentally :-) At least
one online CPU still has to be targeted. */
else if (!(new_value & cpu_present_mask))
return -EINVAL;
else {
irq_affinity[irq] = new_value;
irq_user_affinity[irq] = 1;
irq_desc[irq].handler->set_affinity(irq, new_value);
}
return full_count;
}
static int
prof_cpu_mask_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
unsigned long *mask = (unsigned long *) data;
if (count < HEX_DIGITS+1)
return -EINVAL;
return sprintf (page, "%016lx\n", *mask);
}
static int
prof_cpu_mask_write_proc(struct file *file, const char *buffer,
unsigned long count, void *data)
{
unsigned long *mask = (unsigned long *) data, full_count = count, err;
unsigned long new_value;
err = parse_hex_value(buffer, count, &new_value);
if (err)
return err;
*mask = new_value;
return full_count;
}
#endif /* CONFIG_SMP */
#define MAX_NAMELEN 10
static void
register_irq_proc (unsigned int irq)
{
#ifdef CONFIG_SMP
struct proc_dir_entry *entry;
#endif
char name [MAX_NAMELEN];
if (!root_irq_dir || (irq_desc[irq].handler == &no_irq_type))
return;
memset(name, 0, MAX_NAMELEN);
sprintf(name, "%d", irq);
/* create /proc/irq/1234 */
irq_dir[irq] = proc_mkdir(name, root_irq_dir);
#ifdef CONFIG_SMP
/* create /proc/irq/1234/smp_affinity */
entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
entry->nlink = 1;
entry->data = (void *)(long)irq;
entry->read_proc = irq_affinity_read_proc;
entry->write_proc = irq_affinity_write_proc;
smp_affinity_entry[irq] = entry;
#endif
}
unsigned long prof_cpu_mask = ~0UL;
void
init_irq_proc (void)
{
#ifdef CONFIG_SMP
struct proc_dir_entry *entry;
#endif
int i;
/* create /proc/irq */
root_irq_dir = proc_mkdir("irq", 0);
#ifdef CONFIG_SMP
/* create /proc/irq/prof_cpu_mask */
entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir);
entry->nlink = 1;
entry->data = (void *)&prof_cpu_mask;
entry->read_proc = prof_cpu_mask_read_proc;
entry->write_proc = prof_cpu_mask_write_proc;
#endif
/*
* Create entries for all existing IRQs.
*/
for (i = 0; i < NR_IRQS; i++) {
if (irq_desc[i].handler == &no_irq_type)
continue;
register_irq_proc(i);
}
}
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;
#if 1
/*
* Sanity-check: shared interrupts should REALLY pass in
* a real dev-ID, otherwise we'll have trouble later trying
* to figure out which interrupt is which (messes up the
* interrupt freeing logic etc).
*/
if ((irqflags & SA_SHIRQ) && !dev_id) {
printk(KERN_ERR
"Bad boy: %s (at %p) called us without a dev_id!\n",
devname, __builtin_return_address(0));
}
#endif
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;
#ifdef CONFIG_SMP
select_smp_affinity(irq);
#endif
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) {
printk(KERN_CRIT "Trying to free IRQ%d\n", irq);
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 - 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);
#ifdef CONFIG_SMP
/* Wait to make sure it's not being used on
another CPU. */
while (desc->status & IRQ_INPROGRESS)
barrier();
#endif
kfree(action);
return;
}
printk(KERN_ERR "Trying to free free IRQ%d\n",irq);
spin_unlock_irqrestore(&desc->lock,flags);
return;
}
}
int
get_irq_list(char *buf)
{
#ifdef CONFIG_SMP
int j;
#endif
int i;
struct irqaction * action;
char *p = buf;
#ifdef CONFIG_SMP
p += sprintf(p, " ");
for (i = 0; i < smp_num_cpus; i++)
p += sprintf(p, "CPU%d ", i);
#ifdef DO_BROADCAST_INTS
for (i = 0; i < smp_num_cpus; i++)
p += sprintf(p, "TRY%d ", i);
#endif
*p++ = '\n';
#endif
for (i = 0; i < NR_IRQS; i++) {
action = irq_desc[i].action;
if (!action)
continue;
p += sprintf(p, "%3d: ",i);
#ifndef CONFIG_SMP
p += sprintf(p, "%10u ", kstat_irqs(i));
#else
for (j = 0; j < smp_num_cpus; j++)
p += sprintf(p, "%10u ",
kstat.irqs[cpu_logical_map(j)][i]);
#ifdef DO_BROADCAST_INTS
for (j = 0; j < smp_num_cpus; j++)
p += sprintf(p, "%10lu ",
irq_attempt(cpu_logical_map(j), i));
#endif
#endif
p += sprintf(p, " %14s", irq_desc[i].handler->typename);
p += sprintf(p, " %c%s",
(action->flags & SA_INTERRUPT)?'+':' ',
action->name);
for (action=action->next; action; action = action->next) {
p += sprintf(p, ", %c%s",
(action->flags & SA_INTERRUPT)?'+':' ',
action->name);
}
*p++ = '\n';
}
#if CONFIG_SMP
p += sprintf(p, "IPI: ");
for (j = 0; j < smp_num_cpus; j++)
p += sprintf(p, "%10lu ",
cpu_data[cpu_logical_map(j)].ipi_count);
p += sprintf(p, "\n");
#endif
p += sprintf(p, "ERR: %10lu\n", irq_err_count);
return p - buf;
}
/*
* handle_irq handles all normal device IRQ's (the special
* SMP cross-CPU interrupts have their own specific
* handlers).
*/
#define MAX_ILLEGAL_IRQS 16
void
handle_irq(int irq, 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 cpu = smp_processor_id();
irq_desc_t *desc = irq_desc + irq;
struct irqaction * action;
unsigned int status;
static unsigned int illegal_count=0;
if ((unsigned) irq > ACTUAL_NR_IRQS && illegal_count < MAX_ILLEGAL_IRQS ) {
irq_err_count++;
illegal_count++;
printk(KERN_CRIT "device_interrupt: illegal interrupt %d\n",
irq);
return;
}
irq_attempt(cpu, irq)++;
spin_lock_irq(&desc->lock); /* mask also the higher prio events */
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 handle_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, regs, action);
spin_lock(&desc->lock);
if (!(desc->status & IRQ_PENDING)
|| (desc->status & IRQ_LEVEL))
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();
}
/*
* 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)
{
int i;
irq_desc_t *desc;
unsigned long delay;
unsigned long val;
/* 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 (!irq_desc[i].action)
irq_desc[i].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) first, enable any unassigned irqs. */
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++) {
irq_desc_t *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;
}
/*
* Return a mask of triggered interrupts (this
* can handle only legacy ISA interrupts).
*/
unsigned int
probe_irq_mask(unsigned long val)
{
int i;
unsigned int mask;
mask = 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) {
/* We only react to ISA interrupts */
if (!(status & IRQ_WAITING)) {
if (i < 16)
mask |= 1 << i;
}
desc->status = status & ~IRQ_AUTODETECT;
desc->handler->shutdown(i);
}
spin_unlock_irq(&desc->lock);
}
return mask & val;
}
/*
* Get the result of the IRQ probe.. A negative result means that
* we have several candidates (but we return the lowest-numbered
* one).
*/
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);
}
if (nr_irqs > 1)
irq_found = -irq_found;
return irq_found;
}
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