2 * linux/kernel/irq/manage.c
4 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
5 * Copyright (C) 2005-2006 Thomas Gleixner
7 * This file contains driver APIs to the irq subsystem.
10 #include <linux/irq.h>
11 #include <linux/kthread.h>
12 #include <linux/module.h>
13 #include <linux/random.h>
14 #include <linux/interrupt.h>
15 #include <linux/slab.h>
16 #include <linux/sched.h>
18 #include "internals.h"
21 * synchronize_irq - wait for pending IRQ handlers (on other CPUs)
22 * @irq: interrupt number to wait for
24 * This function waits for any pending IRQ handlers for this interrupt
25 * to complete before returning. If you use this function while
26 * holding a resource the IRQ handler may need you will deadlock.
28 * This function may be called - with care - from IRQ context.
30 void synchronize_irq(unsigned int irq
)
32 struct irq_desc
*desc
= irq_to_desc(irq
);
42 * Wait until we're out of the critical section. This might
43 * give the wrong answer due to the lack of memory barriers.
45 while (desc
->status
& IRQ_INPROGRESS
)
48 /* Ok, that indicated we're done: double-check carefully. */
49 raw_spin_lock_irqsave(&desc
->lock
, flags
);
50 status
= desc
->status
;
51 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
53 /* Oops, that failed? */
54 } while (status
& IRQ_INPROGRESS
);
57 * We made sure that no hardirq handler is running. Now verify
58 * that no threaded handlers are active.
60 wait_event(desc
->wait_for_threads
, !atomic_read(&desc
->threads_active
));
62 EXPORT_SYMBOL(synchronize_irq
);
65 cpumask_var_t irq_default_affinity
;
68 * irq_can_set_affinity - Check if the affinity of a given irq can be set
69 * @irq: Interrupt to check
72 int irq_can_set_affinity(unsigned int irq
)
74 struct irq_desc
*desc
= irq_to_desc(irq
);
76 if (CHECK_IRQ_PER_CPU(desc
->status
) || !desc
->chip
||
77 !desc
->chip
->set_affinity
)
84 * irq_set_thread_affinity - Notify irq threads to adjust affinity
85 * @desc: irq descriptor which has affitnity changed
87 * We just set IRQTF_AFFINITY and delegate the affinity setting
88 * to the interrupt thread itself. We can not call
89 * set_cpus_allowed_ptr() here as we hold desc->lock and this
90 * code can be called from hard interrupt context.
92 void irq_set_thread_affinity(struct irq_desc
*desc
)
94 struct irqaction
*action
= desc
->action
;
98 set_bit(IRQTF_AFFINITY
, &action
->thread_flags
);
99 action
= action
->next
;
104 * irq_set_affinity - Set the irq affinity of a given irq
105 * @irq: Interrupt to set affinity
109 int irq_set_affinity(unsigned int irq
, const struct cpumask
*cpumask
)
111 struct irq_desc
*desc
= irq_to_desc(irq
);
114 if (!desc
->chip
->set_affinity
)
117 raw_spin_lock_irqsave(&desc
->lock
, flags
);
119 #ifdef CONFIG_GENERIC_PENDING_IRQ
120 if (desc
->status
& IRQ_MOVE_PCNTXT
) {
121 if (!desc
->chip
->set_affinity(irq
, cpumask
)) {
122 cpumask_copy(desc
->affinity
, cpumask
);
123 irq_set_thread_affinity(desc
);
127 desc
->status
|= IRQ_MOVE_PENDING
;
128 cpumask_copy(desc
->pending_mask
, cpumask
);
131 if (!desc
->chip
->set_affinity(irq
, cpumask
)) {
132 cpumask_copy(desc
->affinity
, cpumask
);
133 irq_set_thread_affinity(desc
);
136 desc
->status
|= IRQ_AFFINITY_SET
;
137 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
141 #ifndef CONFIG_AUTO_IRQ_AFFINITY
143 * Generic version of the affinity autoselector.
145 static int setup_affinity(unsigned int irq
, struct irq_desc
*desc
)
147 if (!irq_can_set_affinity(irq
))
151 * Preserve an userspace affinity setup, but make sure that
152 * one of the targets is online.
154 if (desc
->status
& (IRQ_AFFINITY_SET
| IRQ_NO_BALANCING
)) {
155 if (cpumask_any_and(desc
->affinity
, cpu_online_mask
)
159 desc
->status
&= ~IRQ_AFFINITY_SET
;
162 cpumask_and(desc
->affinity
, cpu_online_mask
, irq_default_affinity
);
164 desc
->chip
->set_affinity(irq
, desc
->affinity
);
169 static inline int setup_affinity(unsigned int irq
, struct irq_desc
*d
)
171 return irq_select_affinity(irq
);
176 * Called when affinity is set via /proc/irq
178 int irq_select_affinity_usr(unsigned int irq
)
180 struct irq_desc
*desc
= irq_to_desc(irq
);
184 raw_spin_lock_irqsave(&desc
->lock
, flags
);
185 ret
= setup_affinity(irq
, desc
);
187 irq_set_thread_affinity(desc
);
188 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
194 static inline int setup_affinity(unsigned int irq
, struct irq_desc
*desc
)
200 void __disable_irq(struct irq_desc
*desc
, unsigned int irq
, bool suspend
)
203 if (!desc
->action
|| (desc
->action
->flags
& IRQF_TIMER
))
205 desc
->status
|= IRQ_SUSPENDED
;
208 if (!desc
->depth
++) {
209 desc
->status
|= IRQ_DISABLED
;
210 desc
->chip
->disable(irq
);
215 * disable_irq_nosync - disable an irq without waiting
216 * @irq: Interrupt to disable
218 * Disable the selected interrupt line. Disables and Enables are
220 * Unlike disable_irq(), this function does not ensure existing
221 * instances of the IRQ handler have completed before returning.
223 * This function may be called from IRQ context.
225 void disable_irq_nosync(unsigned int irq
)
227 struct irq_desc
*desc
= irq_to_desc(irq
);
233 chip_bus_lock(irq
, desc
);
234 raw_spin_lock_irqsave(&desc
->lock
, flags
);
235 __disable_irq(desc
, irq
, false);
236 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
237 chip_bus_sync_unlock(irq
, desc
);
239 EXPORT_SYMBOL(disable_irq_nosync
);
242 * disable_irq - disable an irq and wait for completion
243 * @irq: Interrupt to disable
245 * Disable the selected interrupt line. Enables and Disables are
247 * This function waits for any pending IRQ handlers for this interrupt
248 * to complete before returning. If you use this function while
249 * holding a resource the IRQ handler may need you will deadlock.
251 * This function may be called - with care - from IRQ context.
253 void disable_irq(unsigned int irq
)
255 struct irq_desc
*desc
= irq_to_desc(irq
);
260 disable_irq_nosync(irq
);
262 synchronize_irq(irq
);
264 EXPORT_SYMBOL(disable_irq
);
266 void __enable_irq(struct irq_desc
*desc
, unsigned int irq
, bool resume
)
269 desc
->status
&= ~IRQ_SUSPENDED
;
271 switch (desc
->depth
) {
274 WARN(1, KERN_WARNING
"Unbalanced enable for IRQ %d\n", irq
);
277 unsigned int status
= desc
->status
& ~IRQ_DISABLED
;
279 if (desc
->status
& IRQ_SUSPENDED
)
281 /* Prevent probing on this irq: */
282 desc
->status
= status
| IRQ_NOPROBE
;
283 check_irq_resend(desc
, irq
);
292 * enable_irq - enable handling of an irq
293 * @irq: Interrupt to enable
295 * Undoes the effect of one call to disable_irq(). If this
296 * matches the last disable, processing of interrupts on this
297 * IRQ line is re-enabled.
299 * This function may be called from IRQ context only when
300 * desc->chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
302 void enable_irq(unsigned int irq
)
304 struct irq_desc
*desc
= irq_to_desc(irq
);
310 chip_bus_lock(irq
, desc
);
311 raw_spin_lock_irqsave(&desc
->lock
, flags
);
312 __enable_irq(desc
, irq
, false);
313 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
314 chip_bus_sync_unlock(irq
, desc
);
316 EXPORT_SYMBOL(enable_irq
);
318 static int set_irq_wake_real(unsigned int irq
, unsigned int on
)
320 struct irq_desc
*desc
= irq_to_desc(irq
);
323 if (desc
->chip
->set_wake
)
324 ret
= desc
->chip
->set_wake(irq
, on
);
330 * set_irq_wake - control irq power management wakeup
331 * @irq: interrupt to control
332 * @on: enable/disable power management wakeup
334 * Enable/disable power management wakeup mode, which is
335 * disabled by default. Enables and disables must match,
336 * just as they match for non-wakeup mode support.
338 * Wakeup mode lets this IRQ wake the system from sleep
339 * states like "suspend to RAM".
341 int set_irq_wake(unsigned int irq
, unsigned int on
)
343 struct irq_desc
*desc
= irq_to_desc(irq
);
347 /* wakeup-capable irqs can be shared between drivers that
348 * don't need to have the same sleep mode behaviors.
350 raw_spin_lock_irqsave(&desc
->lock
, flags
);
352 if (desc
->wake_depth
++ == 0) {
353 ret
= set_irq_wake_real(irq
, on
);
355 desc
->wake_depth
= 0;
357 desc
->status
|= IRQ_WAKEUP
;
360 if (desc
->wake_depth
== 0) {
361 WARN(1, "Unbalanced IRQ %d wake disable\n", irq
);
362 } else if (--desc
->wake_depth
== 0) {
363 ret
= set_irq_wake_real(irq
, on
);
365 desc
->wake_depth
= 1;
367 desc
->status
&= ~IRQ_WAKEUP
;
371 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
374 EXPORT_SYMBOL(set_irq_wake
);
377 * Internal function that tells the architecture code whether a
378 * particular irq has been exclusively allocated or is available
381 int can_request_irq(unsigned int irq
, unsigned long irqflags
)
383 struct irq_desc
*desc
= irq_to_desc(irq
);
384 struct irqaction
*action
;
389 if (desc
->status
& IRQ_NOREQUEST
)
392 action
= desc
->action
;
394 if (irqflags
& action
->flags
& IRQF_SHARED
)
400 void compat_irq_chip_set_default_handler(struct irq_desc
*desc
)
403 * If the architecture still has not overriden
404 * the flow handler then zap the default. This
405 * should catch incorrect flow-type setting.
407 if (desc
->handle_irq
== &handle_bad_irq
)
408 desc
->handle_irq
= NULL
;
411 int __irq_set_trigger(struct irq_desc
*desc
, unsigned int irq
,
415 struct irq_chip
*chip
= desc
->chip
;
417 if (!chip
|| !chip
->set_type
) {
419 * IRQF_TRIGGER_* but the PIC does not support multiple
422 pr_debug("No set_type function for IRQ %d (%s)\n", irq
,
423 chip
? (chip
->name
? : "unknown") : "unknown");
427 /* caller masked out all except trigger mode flags */
428 ret
= chip
->set_type(irq
, flags
);
431 pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
432 (int)flags
, irq
, chip
->set_type
);
434 if (flags
& (IRQ_TYPE_LEVEL_LOW
| IRQ_TYPE_LEVEL_HIGH
))
436 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
437 desc
->status
&= ~(IRQ_LEVEL
| IRQ_TYPE_SENSE_MASK
);
438 desc
->status
|= flags
;
440 if (chip
!= desc
->chip
)
441 irq_chip_set_defaults(desc
->chip
);
448 * Default primary interrupt handler for threaded interrupts. Is
449 * assigned as primary handler when request_threaded_irq is called
450 * with handler == NULL. Useful for oneshot interrupts.
452 static irqreturn_t
irq_default_primary_handler(int irq
, void *dev_id
)
454 return IRQ_WAKE_THREAD
;
458 * Primary handler for nested threaded interrupts. Should never be
461 static irqreturn_t
irq_nested_primary_handler(int irq
, void *dev_id
)
463 WARN(1, "Primary handler called for nested irq %d\n", irq
);
467 static int irq_wait_for_interrupt(struct irqaction
*action
)
469 while (!kthread_should_stop()) {
470 set_current_state(TASK_INTERRUPTIBLE
);
472 if (test_and_clear_bit(IRQTF_RUNTHREAD
,
473 &action
->thread_flags
)) {
474 __set_current_state(TASK_RUNNING
);
483 * Oneshot interrupts keep the irq line masked until the threaded
484 * handler finished. unmask if the interrupt has not been disabled and
487 static void irq_finalize_oneshot(unsigned int irq
, struct irq_desc
*desc
)
490 chip_bus_lock(irq
, desc
);
491 raw_spin_lock_irq(&desc
->lock
);
494 * Implausible though it may be we need to protect us against
495 * the following scenario:
497 * The thread is faster done than the hard interrupt handler
498 * on the other CPU. If we unmask the irq line then the
499 * interrupt can come in again and masks the line, leaves due
500 * to IRQ_INPROGRESS and the irq line is masked forever.
502 if (unlikely(desc
->status
& IRQ_INPROGRESS
)) {
503 raw_spin_unlock_irq(&desc
->lock
);
504 chip_bus_sync_unlock(irq
, desc
);
509 if (!(desc
->status
& IRQ_DISABLED
) && (desc
->status
& IRQ_MASKED
)) {
510 desc
->status
&= ~IRQ_MASKED
;
511 desc
->chip
->unmask(irq
);
513 raw_spin_unlock_irq(&desc
->lock
);
514 chip_bus_sync_unlock(irq
, desc
);
519 * Check whether we need to change the affinity of the interrupt thread.
522 irq_thread_check_affinity(struct irq_desc
*desc
, struct irqaction
*action
)
526 if (!test_and_clear_bit(IRQTF_AFFINITY
, &action
->thread_flags
))
530 * In case we are out of memory we set IRQTF_AFFINITY again and
531 * try again next time
533 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
)) {
534 set_bit(IRQTF_AFFINITY
, &action
->thread_flags
);
538 raw_spin_lock_irq(&desc
->lock
);
539 cpumask_copy(mask
, desc
->affinity
);
540 raw_spin_unlock_irq(&desc
->lock
);
542 set_cpus_allowed_ptr(current
, mask
);
543 free_cpumask_var(mask
);
547 irq_thread_check_affinity(struct irq_desc
*desc
, struct irqaction
*action
) { }
551 * Interrupt handler thread
553 static int irq_thread(void *data
)
555 struct sched_param param
= { .sched_priority
= MAX_USER_RT_PRIO
/2, };
556 struct irqaction
*action
= data
;
557 struct irq_desc
*desc
= irq_to_desc(action
->irq
);
558 int wake
, oneshot
= desc
->status
& IRQ_ONESHOT
;
560 sched_setscheduler(current
, SCHED_FIFO
, ¶m
);
561 current
->irqaction
= action
;
563 while (!irq_wait_for_interrupt(action
)) {
565 irq_thread_check_affinity(desc
, action
);
567 atomic_inc(&desc
->threads_active
);
569 raw_spin_lock_irq(&desc
->lock
);
570 if (unlikely(desc
->status
& IRQ_DISABLED
)) {
572 * CHECKME: We might need a dedicated
573 * IRQ_THREAD_PENDING flag here, which
574 * retriggers the thread in check_irq_resend()
575 * but AFAICT IRQ_PENDING should be fine as it
576 * retriggers the interrupt itself --- tglx
578 desc
->status
|= IRQ_PENDING
;
579 raw_spin_unlock_irq(&desc
->lock
);
581 raw_spin_unlock_irq(&desc
->lock
);
583 action
->thread_fn(action
->irq
, action
->dev_id
);
586 irq_finalize_oneshot(action
->irq
, desc
);
589 wake
= atomic_dec_and_test(&desc
->threads_active
);
591 if (wake
&& waitqueue_active(&desc
->wait_for_threads
))
592 wake_up(&desc
->wait_for_threads
);
596 * Clear irqaction. Otherwise exit_irq_thread() would make
597 * fuzz about an active irq thread going into nirvana.
599 current
->irqaction
= NULL
;
604 * Called from do_exit()
606 void exit_irq_thread(void)
608 struct task_struct
*tsk
= current
;
614 "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
615 tsk
->comm
? tsk
->comm
: "", tsk
->pid
, tsk
->irqaction
->irq
);
618 * Set the THREAD DIED flag to prevent further wakeups of the
619 * soon to be gone threaded handler.
621 set_bit(IRQTF_DIED
, &tsk
->irqaction
->flags
);
625 * Internal function to register an irqaction - typically used to
626 * allocate special interrupts that are part of the architecture.
629 __setup_irq(unsigned int irq
, struct irq_desc
*desc
, struct irqaction
*new)
631 struct irqaction
*old
, **old_ptr
;
632 const char *old_name
= NULL
;
634 int nested
, shared
= 0;
640 if (desc
->chip
== &no_irq_chip
)
643 * Some drivers like serial.c use request_irq() heavily,
644 * so we have to be careful not to interfere with a
647 if (new->flags
& IRQF_SAMPLE_RANDOM
) {
649 * This function might sleep, we want to call it first,
650 * outside of the atomic block.
651 * Yes, this might clear the entropy pool if the wrong
652 * driver is attempted to be loaded, without actually
653 * installing a new handler, but is this really a problem,
654 * only the sysadmin is able to do this.
656 rand_initialize_irq(irq
);
659 /* Oneshot interrupts are not allowed with shared */
660 if ((new->flags
& IRQF_ONESHOT
) && (new->flags
& IRQF_SHARED
))
664 * Check whether the interrupt nests into another interrupt
667 nested
= desc
->status
& IRQ_NESTED_THREAD
;
672 * Replace the primary handler which was provided from
673 * the driver for non nested interrupt handling by the
674 * dummy function which warns when called.
676 new->handler
= irq_nested_primary_handler
;
680 * Create a handler thread when a thread function is supplied
681 * and the interrupt does not nest into another interrupt
684 if (new->thread_fn
&& !nested
) {
685 struct task_struct
*t
;
687 t
= kthread_create(irq_thread
, new, "irq/%d-%s", irq
,
692 * We keep the reference to the task struct even if
693 * the thread dies to avoid that the interrupt code
694 * references an already freed task_struct.
701 * The following block of code has to be executed atomically
703 raw_spin_lock_irqsave(&desc
->lock
, flags
);
704 old_ptr
= &desc
->action
;
708 * Can't share interrupts unless both agree to and are
709 * the same type (level, edge, polarity). So both flag
710 * fields must have IRQF_SHARED set and the bits which
711 * set the trigger type must match.
713 if (!((old
->flags
& new->flags
) & IRQF_SHARED
) ||
714 ((old
->flags
^ new->flags
) & IRQF_TRIGGER_MASK
)) {
715 old_name
= old
->name
;
719 #if defined(CONFIG_IRQ_PER_CPU)
720 /* All handlers must agree on per-cpuness */
721 if ((old
->flags
& IRQF_PERCPU
) !=
722 (new->flags
& IRQF_PERCPU
))
726 /* add new interrupt at end of irq queue */
728 old_ptr
= &old
->next
;
735 irq_chip_set_defaults(desc
->chip
);
737 init_waitqueue_head(&desc
->wait_for_threads
);
739 /* Setup the type (level, edge polarity) if configured: */
740 if (new->flags
& IRQF_TRIGGER_MASK
) {
741 ret
= __irq_set_trigger(desc
, irq
,
742 new->flags
& IRQF_TRIGGER_MASK
);
747 compat_irq_chip_set_default_handler(desc
);
748 #if defined(CONFIG_IRQ_PER_CPU)
749 if (new->flags
& IRQF_PERCPU
)
750 desc
->status
|= IRQ_PER_CPU
;
753 desc
->status
&= ~(IRQ_AUTODETECT
| IRQ_WAITING
| IRQ_ONESHOT
|
754 IRQ_INPROGRESS
| IRQ_SPURIOUS_DISABLED
);
756 if (new->flags
& IRQF_ONESHOT
)
757 desc
->status
|= IRQ_ONESHOT
;
760 * Force MSI interrupts to run with interrupts
761 * disabled. The multi vector cards can cause stack
762 * overflows due to nested interrupts when enough of
763 * them are directed to a core and fire at the same
767 new->flags
|= IRQF_DISABLED
;
769 if (!(desc
->status
& IRQ_NOAUTOEN
)) {
771 desc
->status
&= ~IRQ_DISABLED
;
772 desc
->chip
->startup(irq
);
774 /* Undo nested disables: */
777 /* Exclude IRQ from balancing if requested */
778 if (new->flags
& IRQF_NOBALANCING
)
779 desc
->status
|= IRQ_NO_BALANCING
;
781 /* Set default affinity mask once everything is setup */
782 setup_affinity(irq
, desc
);
784 } else if ((new->flags
& IRQF_TRIGGER_MASK
)
785 && (new->flags
& IRQF_TRIGGER_MASK
)
786 != (desc
->status
& IRQ_TYPE_SENSE_MASK
)) {
787 /* hope the handler works with the actual trigger mode... */
788 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
789 irq
, (int)(desc
->status
& IRQ_TYPE_SENSE_MASK
),
790 (int)(new->flags
& IRQF_TRIGGER_MASK
));
796 /* Reset broken irq detection when installing new handler */
798 desc
->irqs_unhandled
= 0;
801 * Check whether we disabled the irq via the spurious handler
802 * before. Reenable it and give it another chance.
804 if (shared
&& (desc
->status
& IRQ_SPURIOUS_DISABLED
)) {
805 desc
->status
&= ~IRQ_SPURIOUS_DISABLED
;
806 __enable_irq(desc
, irq
, false);
809 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
812 * Strictly no need to wake it up, but hung_task complains
813 * when no hard interrupt wakes the thread up.
816 wake_up_process(new->thread
);
818 register_irq_proc(irq
, desc
);
820 register_handler_proc(irq
, new);
825 #ifdef CONFIG_DEBUG_SHIRQ
826 if (!(new->flags
& IRQF_PROBE_SHARED
)) {
827 printk(KERN_ERR
"IRQ handler type mismatch for IRQ %d\n", irq
);
829 printk(KERN_ERR
"current handler: %s\n", old_name
);
836 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
838 struct task_struct
*t
= new->thread
;
841 if (likely(!test_bit(IRQTF_DIED
, &new->thread_flags
)))
849 * setup_irq - setup an interrupt
850 * @irq: Interrupt line to setup
851 * @act: irqaction for the interrupt
853 * Used to statically setup interrupts in the early boot process.
855 int setup_irq(unsigned int irq
, struct irqaction
*act
)
857 struct irq_desc
*desc
= irq_to_desc(irq
);
859 return __setup_irq(irq
, desc
, act
);
861 EXPORT_SYMBOL_GPL(setup_irq
);
864 * Internal function to unregister an irqaction - used to free
865 * regular and special interrupts that are part of the architecture.
867 static struct irqaction
*__free_irq(unsigned int irq
, void *dev_id
)
869 struct irq_desc
*desc
= irq_to_desc(irq
);
870 struct irqaction
*action
, **action_ptr
;
873 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq
);
878 raw_spin_lock_irqsave(&desc
->lock
, flags
);
881 * There can be multiple actions per IRQ descriptor, find the right
882 * one based on the dev_id:
884 action_ptr
= &desc
->action
;
886 action
= *action_ptr
;
889 WARN(1, "Trying to free already-free IRQ %d\n", irq
);
890 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
895 if (action
->dev_id
== dev_id
)
897 action_ptr
= &action
->next
;
900 /* Found it - now remove it from the list of entries: */
901 *action_ptr
= action
->next
;
903 /* Currently used only by UML, might disappear one day: */
904 #ifdef CONFIG_IRQ_RELEASE_METHOD
905 if (desc
->chip
->release
)
906 desc
->chip
->release(irq
, dev_id
);
909 /* If this was the last handler, shut down the IRQ line: */
911 desc
->status
|= IRQ_DISABLED
;
912 if (desc
->chip
->shutdown
)
913 desc
->chip
->shutdown(irq
);
915 desc
->chip
->disable(irq
);
918 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
920 unregister_handler_proc(irq
, action
);
922 /* Make sure it's not being used on another CPU: */
923 synchronize_irq(irq
);
925 #ifdef CONFIG_DEBUG_SHIRQ
927 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
928 * event to happen even now it's being freed, so let's make sure that
929 * is so by doing an extra call to the handler ....
931 * ( We do this after actually deregistering it, to make sure that a
932 * 'real' IRQ doesn't run in * parallel with our fake. )
934 if (action
->flags
& IRQF_SHARED
) {
935 local_irq_save(flags
);
936 action
->handler(irq
, dev_id
);
937 local_irq_restore(flags
);
941 if (action
->thread
) {
942 if (!test_bit(IRQTF_DIED
, &action
->thread_flags
))
943 kthread_stop(action
->thread
);
944 put_task_struct(action
->thread
);
951 * remove_irq - free an interrupt
952 * @irq: Interrupt line to free
953 * @act: irqaction for the interrupt
955 * Used to remove interrupts statically setup by the early boot process.
957 void remove_irq(unsigned int irq
, struct irqaction
*act
)
959 __free_irq(irq
, act
->dev_id
);
961 EXPORT_SYMBOL_GPL(remove_irq
);
964 * free_irq - free an interrupt allocated with request_irq
965 * @irq: Interrupt line to free
966 * @dev_id: Device identity to free
968 * Remove an interrupt handler. The handler is removed and if the
969 * interrupt line is no longer in use by any driver it is disabled.
970 * On a shared IRQ the caller must ensure the interrupt is disabled
971 * on the card it drives before calling this function. The function
972 * does not return until any executing interrupts for this IRQ
975 * This function must not be called from interrupt context.
977 void free_irq(unsigned int irq
, void *dev_id
)
979 struct irq_desc
*desc
= irq_to_desc(irq
);
984 chip_bus_lock(irq
, desc
);
985 kfree(__free_irq(irq
, dev_id
));
986 chip_bus_sync_unlock(irq
, desc
);
988 EXPORT_SYMBOL(free_irq
);
991 * request_threaded_irq - allocate an interrupt line
992 * @irq: Interrupt line to allocate
993 * @handler: Function to be called when the IRQ occurs.
994 * Primary handler for threaded interrupts
995 * If NULL and thread_fn != NULL the default
996 * primary handler is installed
997 * @thread_fn: Function called from the irq handler thread
998 * If NULL, no irq thread is created
999 * @irqflags: Interrupt type flags
1000 * @devname: An ascii name for the claiming device
1001 * @dev_id: A cookie passed back to the handler function
1003 * This call allocates interrupt resources and enables the
1004 * interrupt line and IRQ handling. From the point this
1005 * call is made your handler function may be invoked. Since
1006 * your handler function must clear any interrupt the board
1007 * raises, you must take care both to initialise your hardware
1008 * and to set up the interrupt handler in the right order.
1010 * If you want to set up a threaded irq handler for your device
1011 * then you need to supply @handler and @thread_fn. @handler ist
1012 * still called in hard interrupt context and has to check
1013 * whether the interrupt originates from the device. If yes it
1014 * needs to disable the interrupt on the device and return
1015 * IRQ_WAKE_THREAD which will wake up the handler thread and run
1016 * @thread_fn. This split handler design is necessary to support
1017 * shared interrupts.
1019 * Dev_id must be globally unique. Normally the address of the
1020 * device data structure is used as the cookie. Since the handler
1021 * receives this value it makes sense to use it.
1023 * If your interrupt is shared you must pass a non NULL dev_id
1024 * as this is required when freeing the interrupt.
1028 * IRQF_SHARED Interrupt is shared
1029 * IRQF_DISABLED Disable local interrupts while processing
1030 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
1031 * IRQF_TRIGGER_* Specify active edge(s) or level
1034 int request_threaded_irq(unsigned int irq
, irq_handler_t handler
,
1035 irq_handler_t thread_fn
, unsigned long irqflags
,
1036 const char *devname
, void *dev_id
)
1038 struct irqaction
*action
;
1039 struct irq_desc
*desc
;
1043 * handle_IRQ_event() always ignores IRQF_DISABLED except for
1044 * the _first_ irqaction (sigh). That can cause oopsing, but
1045 * the behavior is classified as "will not fix" so we need to
1046 * start nudging drivers away from using that idiom.
1048 if ((irqflags
& (IRQF_SHARED
|IRQF_DISABLED
)) ==
1049 (IRQF_SHARED
|IRQF_DISABLED
)) {
1051 "IRQ %d/%s: IRQF_DISABLED is not guaranteed on shared IRQs\n",
1055 #ifdef CONFIG_LOCKDEP
1057 * Lockdep wants atomic interrupt handlers:
1059 irqflags
|= IRQF_DISABLED
;
1062 * Sanity-check: shared interrupts must pass in a real dev-ID,
1063 * otherwise we'll have trouble later trying to figure out
1064 * which interrupt is which (messes up the interrupt freeing
1067 if ((irqflags
& IRQF_SHARED
) && !dev_id
)
1070 desc
= irq_to_desc(irq
);
1074 if (desc
->status
& IRQ_NOREQUEST
)
1080 handler
= irq_default_primary_handler
;
1083 action
= kzalloc(sizeof(struct irqaction
), GFP_KERNEL
);
1087 action
->handler
= handler
;
1088 action
->thread_fn
= thread_fn
;
1089 action
->flags
= irqflags
;
1090 action
->name
= devname
;
1091 action
->dev_id
= dev_id
;
1093 chip_bus_lock(irq
, desc
);
1094 retval
= __setup_irq(irq
, desc
, action
);
1095 chip_bus_sync_unlock(irq
, desc
);
1100 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1101 if (!retval
&& (irqflags
& IRQF_SHARED
)) {
1103 * It's a shared IRQ -- the driver ought to be prepared for it
1104 * to happen immediately, so let's make sure....
1105 * We disable the irq to make sure that a 'real' IRQ doesn't
1106 * run in parallel with our fake.
1108 unsigned long flags
;
1111 local_irq_save(flags
);
1113 handler(irq
, dev_id
);
1115 local_irq_restore(flags
);
1121 EXPORT_SYMBOL(request_threaded_irq
);