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/*
* linux/arch/i386/kernel/irq.c
*
* Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
*
* 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.
*/
/*
* (mostly architecture independent, will move to kernel/irq.c in 2.5.)
*
* 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/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_lock.h>
#include <linux/init.h>
#include <linux/kernel_stat.h>
#include <linux/irq.h>
#include <linux/proc_fs.h>
#include <asm/atomic.h>
#include <asm/io.h>
#include <asm/smp.h>
#include <asm/system.h>
#include <asm/bitops.h>
#include <asm/uaccess.h>
#include <asm/pgalloc.h>
#include <asm/delay.h>
#include <asm/desc.h>
#include <asm/irq.h>
/*
* Linux has a controller-independent x86 interrupt architecture.
* every controller has a 'controller-template', that is used
* by the main code to do the right thing. Each driver-visible
* interrupt source is transparently wired to the apropriate
* controller. Thus drivers need not be aware of the
* interrupt-controller.
*
* Various interrupt controllers we handle: 8259 PIC, SMP IO-APIC,
* PIIX4's internal 8259 PIC and SGI's Visual Workstation Cobalt (IO-)APIC.
* (IO-APICs assumed to be messaging to Pentium local-APICs)
*
* the code is designed to be easily extended with new/different
* interrupt controllers, without having to do assembly magic.
*/
/*
* 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);
/*
* 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.
*/
#if CONFIG_X86
printk("unexpected IRQ trap at vector %02x\n", irq);
#ifdef CONFIG_X86_LOCAL_APIC
/*
* Currently unexpected vectors happen only on SMP and APIC.
* We _must_ ack these because every local APIC has only N
* irq slots per priority level, and a 'hanging, unacked' IRQ
* holds up an irq slot - in excessive cases (when multiple
* unexpected vectors occur) that might lock up the APIC
* completely.
*/
ack_APIC_irq();
#endif
#endif
}
/* 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
};
atomic_t irq_err_count;
#ifdef CONFIG_X86_IO_APIC
#ifdef APIC_MISMATCH_DEBUG
atomic_t irq_mis_count;
#endif
#endif
/*
* Generic, controller-independent functions:
*/
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 < 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]);
#endif
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';
}
p += sprintf(p, "NMI: ");
for (j = 0; j < smp_num_cpus; j++)
p += sprintf(p, "%10u ",
nmi_count(cpu_logical_map(j)));
p += sprintf(p, "\n");
#if CONFIG_X86_LOCAL_APIC
p += sprintf(p, "LOC: ");
for (j = 0; j < smp_num_cpus; j++)
p += sprintf(p, "%10u ",
apic_timer_irqs[cpu_logical_map(j)]);
p += sprintf(p, "\n");
#endif
p += sprintf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
#ifdef CONFIG_X86_IO_APIC
#ifdef APIC_MISMATCH_DEBUG
p += sprintf(p, "MIS: %10u\n", atomic_read(&irq_mis_count));
#endif
#endif
return p - buf;
}
/*
* Global interrupt locks for SMP. Allow interrupts to come in on any
* CPU, yet make cli/sti act globally to protect critical regions..
*/
#ifdef CONFIG_SMP
unsigned char global_irq_holder = NO_PROC_ID;
unsigned volatile long global_irq_lock; /* pendantic: long for set_bit --RR */
extern void show_stack(unsigned long* esp);
static void show(char * str)
{
int i;
int cpu = smp_processor_id();
printk("\n%s, CPU %d:\n", str, cpu);
printk("irq: %d [",irqs_running());
for(i=0;i < smp_num_cpus;i++)
printk(" %d",local_irq_count(i));
printk(" ]\nbh: %d [",spin_is_locked(&global_bh_lock) ? 1 : 0);
for(i=0;i < smp_num_cpus;i++)
printk(" %d",local_bh_count(i));
printk(" ]\nStack dumps:");
for(i = 0; i < smp_num_cpus; i++) {
unsigned long esp;
if (i == cpu)
continue;
printk("\nCPU %d:",i);
esp = init_tss[i].esp0;
if (!esp) {
/* tss->esp0 is set to NULL in cpu_init(),
* it's initialized when the cpu returns to user
* space. -- manfreds
*/
printk(" <unknown> ");
continue;
}
esp &= ~(THREAD_SIZE-1);
esp += sizeof(struct task_struct);
show_stack((void*)esp);
}
printk("\nCPU %d:",cpu);
show_stack(NULL);
printk("\n");
}
#define MAXCOUNT 100000000
/*
* I had a lockup scenario where a tight loop doing
* spin_unlock()/spin_lock() on CPU#1 was racing with
* spin_lock() on CPU#0. CPU#0 should have noticed spin_unlock(), but
* apparently the spin_unlock() information did not make it
* through to CPU#0 ... nasty, is this by design, do we have to limit
* 'memory update oscillation frequency' artificially like here?
*
* Such 'high frequency update' races can be avoided by careful design, but
* some of our major constructs like spinlocks use similar techniques,
* it would be nice to clarify this issue. Set this define to 0 if you
* want to check whether your system freezes. I suspect the delay done
* by SYNC_OTHER_CORES() is in correlation with 'snooping latency', but
* i thought that such things are guaranteed by design, since we use
* the 'LOCK' prefix.
*/
#define SUSPECTED_CPU_OR_CHIPSET_BUG_WORKAROUND 0
#if SUSPECTED_CPU_OR_CHIPSET_BUG_WORKAROUND
# define SYNC_OTHER_CORES(x) udelay(x+1)
#else
/*
* We have to allow irqs to arrive between __sti and __cli
*/
# define SYNC_OTHER_CORES(x) __asm__ __volatile__ ("nop")
#endif
static inline void wait_on_irq(int cpu)
{
int count = MAXCOUNT;
for (;;) {
/*
* Wait until all interrupts are gone. Wait
* for bottom half handlers unless we're
* already executing in one..
*/
if (!irqs_running())
if (local_bh_count(cpu) || !spin_is_locked(&global_bh_lock))
break;
/* Duh, we have to loop. Release the lock to avoid deadlocks */
clear_bit(0,&global_irq_lock);
for (;;) {
if (!--count) {
show("wait_on_irq");
count = ~0;
}
__sti();
SYNC_OTHER_CORES(cpu);
__cli();
if (irqs_running())
continue;
if (global_irq_lock)
continue;
if (!local_bh_count(cpu) && spin_is_locked(&global_bh_lock))
continue;
if (!test_and_set_bit(0,&global_irq_lock))
break;
}
}
}
/*
* This is called when we want to synchronize with
* interrupts. We may for example tell a device to
* stop sending interrupts: but to make sure there
* are no interrupts that are executing on another
* CPU we need to call this function.
*/
void synchronize_irq(void)
{
if (irqs_running()) {
/* Stupid approach */
cli();
sti();
}
}
static inline void get_irqlock(int cpu)
{
if (test_and_set_bit(0,&global_irq_lock)) {
/* do we already hold the lock? */
if ((unsigned char) cpu == global_irq_holder)
return;
/* Uhhuh.. Somebody else got it. Wait.. */
do {
do {
rep_nop();
} while (test_bit(0,&global_irq_lock));
} while (test_and_set_bit(0,&global_irq_lock));
}
/*
* We also to make sure that nobody else is running
* in an interrupt context.
*/
wait_on_irq(cpu);
/*
* Ok, finally..
*/
global_irq_holder = cpu;
}
#define EFLAGS_IF_SHIFT 9
/*
* A global "cli()" while in an interrupt context
* turns into just a local cli(). Interrupts
* should use spinlocks for the (very unlikely)
* case that they ever want to protect against
* each other.
*
* If we already have local interrupts disabled,
* this will not turn a local disable into a
* global one (problems with spinlocks: this makes
* save_flags+cli+sti usable inside a spinlock).
*/
void __global_cli(void)
{
unsigned int flags;
__save_flags(flags);
if (flags & (1 << EFLAGS_IF_SHIFT)) {
int cpu = smp_processor_id();
__cli();
if (!local_irq_count(cpu))
get_irqlock(cpu);
}
}
void __global_sti(void)
{
int cpu = smp_processor_id();
if (!local_irq_count(cpu))
release_irqlock(cpu);
__sti();
}
/*
* SMP flags value to restore to:
* 0 - global cli
* 1 - global sti
* 2 - local cli
* 3 - local sti
*/
unsigned long __global_save_flags(void)
{
int retval;
int local_enabled;
unsigned long flags;
int cpu = smp_processor_id();
__save_flags(flags);
local_enabled = (flags >> EFLAGS_IF_SHIFT) & 1;
/* default to local */
retval = 2 + local_enabled;
/* check for global flags if we're not in an interrupt */
if (!local_irq_count(cpu)) {
if (local_enabled)
retval = 1;
if (global_irq_holder == cpu)
retval = 0;
}
return retval;
}
void __global_restore_flags(unsigned long flags)
{
switch (flags) {
case 0:
__global_cli();
break;
case 1:
__global_sti();
break;
case 2:
__cli();
break;
case 3:
__sti();
break;
default:
printk("global_restore_flags: %08lx (%08lx)\n",
flags, (&flags)[-1]);
}
}
#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.
*/
/**
* disable_irq_nosync - disable an irq without waiting
* @irq: Interrupt to disable
*
* Disable the selected interrupt line. Disables and Enables are
* nested.
* Unlike disable_irq(), this function does not ensure existing
* instances of the IRQ handler have completed before returning.
*
* This function may be called from IRQ context.
*/
inline 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);
}
/**
* disable_irq - disable an irq and wait for completion
* @irq: Interrupt to disable
*
* Disable the selected interrupt line. Enables and Disables are
* nested.
* This function waits for any pending IRQ handlers for this interrupt
* to complete before returning. If you use this function while
* holding a resource the IRQ handler may need you will deadlock.
*
* This function may be called - with care - from IRQ context.
*/
void disable_irq(unsigned int irq)
{
disable_irq_nosync(irq);
if (!local_irq_count(smp_processor_id())) {
do {
barrier();
cpu_relax();
} while (irq_desc[irq].status & IRQ_INPROGRESS);
}
}
/**
* enable_irq - enable handling of an irq
* @irq: Interrupt to enable
*
* Undoes the effect of one call to disable_irq(). If this
* matches the last disable, processing of interrupts on this
* IRQ line is re-enabled.
*
* This function may be called from IRQ context.
*/
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(%u) unbalanced from %p\n", irq,
__builtin_return_address(0));
}
spin_unlock_irqrestore(&desc->lock, flags);
}
/*
* do_IRQ handles all normal device IRQ's (the special
* SMP cross-CPU interrupts have their own specific
* handlers).
*/
asmlinkage unsigned int do_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 irq = regs.orig_eax & 0xff; /* high bits used in ret_from_ code */
int cpu = smp_processor_id();
irq_desc_t *desc = irq_desc + irq;
struct irqaction * action;
unsigned int status;
kstat.irqs[cpu][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;
}
/**
* request_irq - allocate an interrupt line
* @irq: Interrupt line to allocate
* @handler: Function to be called when the IRQ occurs
* @irqflags: Interrupt type flags
* @devname: An ascii name for the claiming device
* @dev_id: A cookie passed back to the handler function
*
* This call allocates interrupt resources and enables the
* interrupt line and IRQ handling. From the point this
* call is made your handler function may be invoked. Since
* your handler function must clear any interrupt the board
* raises, you must take care both to initialise your hardware
* and to set up the interrupt handler in the right order.
*
* Dev_id must be globally unique. Normally the address of the
* device data structure is used as the cookie. Since the handler
* receives this value it makes sense to use it.
*
* If your interrupt is shared you must pass a non NULL dev_id
* as this is required when freeing the interrupt.
*
* Flags:
*
* SA_SHIRQ Interrupt is shared
*
* SA_INTERRUPT Disable local interrupts while processing
*
* SA_SAMPLE_RANDOM The interrupt can be used for entropy
*
*/
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 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) {
if (!dev_id)
printk("Bad boy: %s (at 0x%x) called us without a dev_id!\n", devname, (&irq)[-1]);
}
#endif
if (irq >= 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;
}
/**
* free_irq - free an interrupt
* @irq: Interrupt line to free
* @dev_id: Device identity to free
*
* Remove an interrupt handler. The handler is removed and if the
* interrupt line is no longer in use by any driver it is disabled.
* On a shared IRQ the caller must ensure the interrupt is disabled
* on the card it drives before calling this function. The function
* does not return until any executing interrupts for this IRQ
* have completed.
*
* This function may be called from interrupt context.
*
* Bugs: Attempting to free an irq in a handler for the same irq hangs
* the machine.
*/
void free_irq(unsigned int irq, void *dev_id)
{
irq_desc_t *desc;
struct irqaction **p;
unsigned long flags;
if (irq >= 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);
#ifdef CONFIG_SMP
/* Wait to make sure it's not being used on another CPU */
while (desc->status & IRQ_INPROGRESS) {
barrier();
cpu_relax();
}
#endif
kfree(action);
return;
}
printk("Trying to free free IRQ%d\n",irq);
spin_unlock_irqrestore(&desc->lock,flags);
return;
}
}
/*
* 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.
*/
static DECLARE_MUTEX(probe_sem);
/**
* probe_irq_on - begin an interrupt autodetect
*
* Commence probing for an interrupt. The interrupts are scanned
* and a mask of potential interrupt lines is returned.
*
*/
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 (!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)
*/
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).
*/
/**
* probe_irq_mask - scan a bitmap of interrupt lines
* @val: mask of interrupts to consider
*
* Scan the ISA bus interrupt lines and return a bitmap of
* active interrupts. The interrupt probe logic state is then
* returned to its previous value.
*
* Note: we need to scan all the irq's even though we will
* only return ISA irq numbers - just so that we reset them
* all to a known state.
*/
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) {
if (i < 16 && !(status & IRQ_WAITING))
mask |= 1 << i;
desc->status = status & ~IRQ_AUTODETECT;
desc->handler->shutdown(i);
}
spin_unlock_irq(&desc->lock);
}
up(&probe_sem);
return mask & val;
}
/*
* Return the one interrupt that triggered (this can
* handle any interrupt source).
*/
/**
* probe_irq_off - end an interrupt autodetect
* @val: mask of potential interrupts (unused)
*
* Scans the unused interrupt lines and returns the line which
* appears to have triggered the interrupt. If no interrupt was
* found then zero is returned. If more than one interrupt is
* found then minus the first candidate is returned to indicate
* their is doubt.
*
* The interrupt probe logic state is returned to its previous
* value.
*
* BUGS: When used in a module (which arguably shouldnt happen)
* nothing prevents two IRQ probe callers from overlapping. The
* results of this are non-optimal.
*/
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;
}
/* this was setup_x86_irq but it seems pretty generic */
int setup_irq(unsigned int irq, struct irqaction * new)
{
int shared = 0;
unsigned long flags;
struct irqaction *old, **p;
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);
register_irq_proc(irq);
return 0;
}
static struct proc_dir_entry * root_irq_dir;
static struct proc_dir_entry * irq_dir [NR_IRQS];
#define HEX_DIGITS 8
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;
}
#if CONFIG_SMP
static struct proc_dir_entry * smp_affinity_entry [NR_IRQS];
static unsigned long irq_affinity [NR_IRQS] = { [0 ... NR_IRQS-1] = ~0UL };
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, "%08lx\n", irq_affinity[(long)data]);
}
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);
/*
* 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.
*/
if (!(new_value & cpu_online_map))
return -EINVAL;
irq_affinity[irq] = new_value;
irq_desc[irq].handler->set_affinity(irq, new_value);
return full_count;
}
#endif
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, "%08lx\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;
}
#define MAX_NAMELEN 10
static void register_irq_proc (unsigned int irq)
{
char name [MAX_NAMELEN];
if (!root_irq_dir || (irq_desc[irq].handler == &no_irq_type) ||
irq_dir[irq])
return;
memset(name, 0, MAX_NAMELEN);
sprintf(name, "%d", irq);
/* create /proc/irq/1234 */
irq_dir[irq] = proc_mkdir(name, root_irq_dir);
#if CONFIG_SMP
{
struct proc_dir_entry *entry;
/* create /proc/irq/1234/smp_affinity */
entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
if (entry) {
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 = -1;
void init_irq_proc (void)
{
struct proc_dir_entry *entry;
int i;
/* create /proc/irq */
root_irq_dir = proc_mkdir("irq", 0);
/* create /proc/irq/prof_cpu_mask */
entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir);
if (!entry)
return;
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;
/*
* Create entries for all existing IRQs.
*/
for (i = 0; i < NR_IRQS; i++)
register_irq_proc(i);
}
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