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 spin_lock_irqsave(&desc
->lock
, flags
);
50 status
= desc
->status
;
51 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 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 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 spin_lock_irqsave(&desc
->lock
, flags
);
185 ret
= setup_affinity(irq
, desc
);
187 irq_set_thread_affinity(desc
);
188 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 spin_lock_irqsave(&desc
->lock
, flags
);
235 __disable_irq(desc
, irq
, false);
236 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 spin_lock_irqsave(&desc
->lock
, flags
);
312 __enable_irq(desc
, irq
, false);
313 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 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 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
;
445 * Default primary interrupt handler for threaded interrupts. Is
446 * assigned as primary handler when request_threaded_irq is called
447 * with handler == NULL. Useful for oneshot interrupts.
449 static irqreturn_t
irq_default_primary_handler(int irq
, void *dev_id
)
451 return IRQ_WAKE_THREAD
;
455 * Primary handler for nested threaded interrupts. Should never be
458 static irqreturn_t
irq_nested_primary_handler(int irq
, void *dev_id
)
460 WARN(1, "Primary handler called for nested irq %d\n", irq
);
464 static int irq_wait_for_interrupt(struct irqaction
*action
)
466 while (!kthread_should_stop()) {
467 set_current_state(TASK_INTERRUPTIBLE
);
469 if (test_and_clear_bit(IRQTF_RUNTHREAD
,
470 &action
->thread_flags
)) {
471 __set_current_state(TASK_RUNNING
);
480 * Oneshot interrupts keep the irq line masked until the threaded
481 * handler finished. unmask if the interrupt has not been disabled and
484 static void irq_finalize_oneshot(unsigned int irq
, struct irq_desc
*desc
)
486 chip_bus_lock(irq
, desc
);
487 spin_lock_irq(&desc
->lock
);
488 if (!(desc
->status
& IRQ_DISABLED
) && (desc
->status
& IRQ_MASKED
)) {
489 desc
->status
&= ~IRQ_MASKED
;
490 desc
->chip
->unmask(irq
);
492 spin_unlock_irq(&desc
->lock
);
493 chip_bus_sync_unlock(irq
, desc
);
498 * Check whether we need to change the affinity of the interrupt thread.
501 irq_thread_check_affinity(struct irq_desc
*desc
, struct irqaction
*action
)
505 if (!test_and_clear_bit(IRQTF_AFFINITY
, &action
->thread_flags
))
509 * In case we are out of memory we set IRQTF_AFFINITY again and
510 * try again next time
512 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
)) {
513 set_bit(IRQTF_AFFINITY
, &action
->thread_flags
);
517 spin_lock_irq(&desc
->lock
);
518 cpumask_copy(mask
, desc
->affinity
);
519 spin_unlock_irq(&desc
->lock
);
521 set_cpus_allowed_ptr(current
, mask
);
522 free_cpumask_var(mask
);
526 irq_thread_check_affinity(struct irq_desc
*desc
, struct irqaction
*action
) { }
530 * Interrupt handler thread
532 static int irq_thread(void *data
)
534 struct sched_param param
= { .sched_priority
= MAX_USER_RT_PRIO
/2, };
535 struct irqaction
*action
= data
;
536 struct irq_desc
*desc
= irq_to_desc(action
->irq
);
537 int wake
, oneshot
= desc
->status
& IRQ_ONESHOT
;
539 sched_setscheduler(current
, SCHED_FIFO
, ¶m
);
540 current
->irqaction
= action
;
542 while (!irq_wait_for_interrupt(action
)) {
544 irq_thread_check_affinity(desc
, action
);
546 atomic_inc(&desc
->threads_active
);
548 spin_lock_irq(&desc
->lock
);
549 if (unlikely(desc
->status
& IRQ_DISABLED
)) {
551 * CHECKME: We might need a dedicated
552 * IRQ_THREAD_PENDING flag here, which
553 * retriggers the thread in check_irq_resend()
554 * but AFAICT IRQ_PENDING should be fine as it
555 * retriggers the interrupt itself --- tglx
557 desc
->status
|= IRQ_PENDING
;
558 spin_unlock_irq(&desc
->lock
);
560 spin_unlock_irq(&desc
->lock
);
562 action
->thread_fn(action
->irq
, action
->dev_id
);
565 irq_finalize_oneshot(action
->irq
, desc
);
568 wake
= atomic_dec_and_test(&desc
->threads_active
);
570 if (wake
&& waitqueue_active(&desc
->wait_for_threads
))
571 wake_up(&desc
->wait_for_threads
);
575 * Clear irqaction. Otherwise exit_irq_thread() would make
576 * fuzz about an active irq thread going into nirvana.
578 current
->irqaction
= NULL
;
583 * Called from do_exit()
585 void exit_irq_thread(void)
587 struct task_struct
*tsk
= current
;
593 "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
594 tsk
->comm
? tsk
->comm
: "", tsk
->pid
, tsk
->irqaction
->irq
);
597 * Set the THREAD DIED flag to prevent further wakeups of the
598 * soon to be gone threaded handler.
600 set_bit(IRQTF_DIED
, &tsk
->irqaction
->flags
);
604 * Internal function to register an irqaction - typically used to
605 * allocate special interrupts that are part of the architecture.
608 __setup_irq(unsigned int irq
, struct irq_desc
*desc
, struct irqaction
*new)
610 struct irqaction
*old
, **old_ptr
;
611 const char *old_name
= NULL
;
613 int nested
, shared
= 0;
619 if (desc
->chip
== &no_irq_chip
)
622 * Some drivers like serial.c use request_irq() heavily,
623 * so we have to be careful not to interfere with a
626 if (new->flags
& IRQF_SAMPLE_RANDOM
) {
628 * This function might sleep, we want to call it first,
629 * outside of the atomic block.
630 * Yes, this might clear the entropy pool if the wrong
631 * driver is attempted to be loaded, without actually
632 * installing a new handler, but is this really a problem,
633 * only the sysadmin is able to do this.
635 rand_initialize_irq(irq
);
638 /* Oneshot interrupts are not allowed with shared */
639 if ((new->flags
& IRQF_ONESHOT
) && (new->flags
& IRQF_SHARED
))
643 * Check whether the interrupt nests into another interrupt
646 nested
= desc
->status
& IRQ_NESTED_THREAD
;
651 * Replace the primary handler which was provided from
652 * the driver for non nested interrupt handling by the
653 * dummy function which warns when called.
655 new->handler
= irq_nested_primary_handler
;
659 * Create a handler thread when a thread function is supplied
660 * and the interrupt does not nest into another interrupt
663 if (new->thread_fn
&& !nested
) {
664 struct task_struct
*t
;
666 t
= kthread_create(irq_thread
, new, "irq/%d-%s", irq
,
671 * We keep the reference to the task struct even if
672 * the thread dies to avoid that the interrupt code
673 * references an already freed task_struct.
681 * The following block of code has to be executed atomically
683 spin_lock_irqsave(&desc
->lock
, flags
);
684 old_ptr
= &desc
->action
;
688 * Can't share interrupts unless both agree to and are
689 * the same type (level, edge, polarity). So both flag
690 * fields must have IRQF_SHARED set and the bits which
691 * set the trigger type must match.
693 if (!((old
->flags
& new->flags
) & IRQF_SHARED
) ||
694 ((old
->flags
^ new->flags
) & IRQF_TRIGGER_MASK
)) {
695 old_name
= old
->name
;
699 #if defined(CONFIG_IRQ_PER_CPU)
700 /* All handlers must agree on per-cpuness */
701 if ((old
->flags
& IRQF_PERCPU
) !=
702 (new->flags
& IRQF_PERCPU
))
706 /* add new interrupt at end of irq queue */
708 old_ptr
= &old
->next
;
715 irq_chip_set_defaults(desc
->chip
);
717 init_waitqueue_head(&desc
->wait_for_threads
);
719 /* Setup the type (level, edge polarity) if configured: */
720 if (new->flags
& IRQF_TRIGGER_MASK
) {
721 ret
= __irq_set_trigger(desc
, irq
,
722 new->flags
& IRQF_TRIGGER_MASK
);
727 compat_irq_chip_set_default_handler(desc
);
728 #if defined(CONFIG_IRQ_PER_CPU)
729 if (new->flags
& IRQF_PERCPU
)
730 desc
->status
|= IRQ_PER_CPU
;
733 desc
->status
&= ~(IRQ_AUTODETECT
| IRQ_WAITING
| IRQ_ONESHOT
|
734 IRQ_INPROGRESS
| IRQ_SPURIOUS_DISABLED
);
736 if (new->flags
& IRQF_ONESHOT
)
737 desc
->status
|= IRQ_ONESHOT
;
739 if (!(desc
->status
& IRQ_NOAUTOEN
)) {
741 desc
->status
&= ~IRQ_DISABLED
;
742 desc
->chip
->startup(irq
);
744 /* Undo nested disables: */
747 /* Exclude IRQ from balancing if requested */
748 if (new->flags
& IRQF_NOBALANCING
)
749 desc
->status
|= IRQ_NO_BALANCING
;
751 /* Set default affinity mask once everything is setup */
752 setup_affinity(irq
, desc
);
754 } else if ((new->flags
& IRQF_TRIGGER_MASK
)
755 && (new->flags
& IRQF_TRIGGER_MASK
)
756 != (desc
->status
& IRQ_TYPE_SENSE_MASK
)) {
757 /* hope the handler works with the actual trigger mode... */
758 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
759 irq
, (int)(desc
->status
& IRQ_TYPE_SENSE_MASK
),
760 (int)(new->flags
& IRQF_TRIGGER_MASK
));
765 /* Reset broken irq detection when installing new handler */
767 desc
->irqs_unhandled
= 0;
770 * Check whether we disabled the irq via the spurious handler
771 * before. Reenable it and give it another chance.
773 if (shared
&& (desc
->status
& IRQ_SPURIOUS_DISABLED
)) {
774 desc
->status
&= ~IRQ_SPURIOUS_DISABLED
;
775 __enable_irq(desc
, irq
, false);
778 spin_unlock_irqrestore(&desc
->lock
, flags
);
781 register_irq_proc(irq
, desc
);
783 register_handler_proc(irq
, new);
788 #ifdef CONFIG_DEBUG_SHIRQ
789 if (!(new->flags
& IRQF_PROBE_SHARED
)) {
790 printk(KERN_ERR
"IRQ handler type mismatch for IRQ %d\n", irq
);
792 printk(KERN_ERR
"current handler: %s\n", old_name
);
799 spin_unlock_irqrestore(&desc
->lock
, flags
);
801 struct task_struct
*t
= new->thread
;
804 if (likely(!test_bit(IRQTF_DIED
, &new->thread_flags
)))
812 * setup_irq - setup an interrupt
813 * @irq: Interrupt line to setup
814 * @act: irqaction for the interrupt
816 * Used to statically setup interrupts in the early boot process.
818 int setup_irq(unsigned int irq
, struct irqaction
*act
)
820 struct irq_desc
*desc
= irq_to_desc(irq
);
822 return __setup_irq(irq
, desc
, act
);
824 EXPORT_SYMBOL_GPL(setup_irq
);
827 * Internal function to unregister an irqaction - used to free
828 * regular and special interrupts that are part of the architecture.
830 static struct irqaction
*__free_irq(unsigned int irq
, void *dev_id
)
832 struct irq_desc
*desc
= irq_to_desc(irq
);
833 struct irqaction
*action
, **action_ptr
;
836 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq
);
841 spin_lock_irqsave(&desc
->lock
, flags
);
844 * There can be multiple actions per IRQ descriptor, find the right
845 * one based on the dev_id:
847 action_ptr
= &desc
->action
;
849 action
= *action_ptr
;
852 WARN(1, "Trying to free already-free IRQ %d\n", irq
);
853 spin_unlock_irqrestore(&desc
->lock
, flags
);
858 if (action
->dev_id
== dev_id
)
860 action_ptr
= &action
->next
;
863 /* Found it - now remove it from the list of entries: */
864 *action_ptr
= action
->next
;
866 /* Currently used only by UML, might disappear one day: */
867 #ifdef CONFIG_IRQ_RELEASE_METHOD
868 if (desc
->chip
->release
)
869 desc
->chip
->release(irq
, dev_id
);
872 /* If this was the last handler, shut down the IRQ line: */
874 desc
->status
|= IRQ_DISABLED
;
875 if (desc
->chip
->shutdown
)
876 desc
->chip
->shutdown(irq
);
878 desc
->chip
->disable(irq
);
881 spin_unlock_irqrestore(&desc
->lock
, flags
);
883 unregister_handler_proc(irq
, action
);
885 /* Make sure it's not being used on another CPU: */
886 synchronize_irq(irq
);
888 #ifdef CONFIG_DEBUG_SHIRQ
890 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
891 * event to happen even now it's being freed, so let's make sure that
892 * is so by doing an extra call to the handler ....
894 * ( We do this after actually deregistering it, to make sure that a
895 * 'real' IRQ doesn't run in * parallel with our fake. )
897 if (action
->flags
& IRQF_SHARED
) {
898 local_irq_save(flags
);
899 action
->handler(irq
, dev_id
);
900 local_irq_restore(flags
);
904 if (action
->thread
) {
905 if (!test_bit(IRQTF_DIED
, &action
->thread_flags
))
906 kthread_stop(action
->thread
);
907 put_task_struct(action
->thread
);
914 * remove_irq - free an interrupt
915 * @irq: Interrupt line to free
916 * @act: irqaction for the interrupt
918 * Used to remove interrupts statically setup by the early boot process.
920 void remove_irq(unsigned int irq
, struct irqaction
*act
)
922 __free_irq(irq
, act
->dev_id
);
924 EXPORT_SYMBOL_GPL(remove_irq
);
927 * free_irq - free an interrupt allocated with request_irq
928 * @irq: Interrupt line to free
929 * @dev_id: Device identity to free
931 * Remove an interrupt handler. The handler is removed and if the
932 * interrupt line is no longer in use by any driver it is disabled.
933 * On a shared IRQ the caller must ensure the interrupt is disabled
934 * on the card it drives before calling this function. The function
935 * does not return until any executing interrupts for this IRQ
938 * This function must not be called from interrupt context.
940 void free_irq(unsigned int irq
, void *dev_id
)
942 struct irq_desc
*desc
= irq_to_desc(irq
);
947 chip_bus_lock(irq
, desc
);
948 kfree(__free_irq(irq
, dev_id
));
949 chip_bus_sync_unlock(irq
, desc
);
951 EXPORT_SYMBOL(free_irq
);
954 * request_threaded_irq - allocate an interrupt line
955 * @irq: Interrupt line to allocate
956 * @handler: Function to be called when the IRQ occurs.
957 * Primary handler for threaded interrupts
958 * If NULL and thread_fn != NULL the default
959 * primary handler is installed
960 * @thread_fn: Function called from the irq handler thread
961 * If NULL, no irq thread is created
962 * @irqflags: Interrupt type flags
963 * @devname: An ascii name for the claiming device
964 * @dev_id: A cookie passed back to the handler function
966 * This call allocates interrupt resources and enables the
967 * interrupt line and IRQ handling. From the point this
968 * call is made your handler function may be invoked. Since
969 * your handler function must clear any interrupt the board
970 * raises, you must take care both to initialise your hardware
971 * and to set up the interrupt handler in the right order.
973 * If you want to set up a threaded irq handler for your device
974 * then you need to supply @handler and @thread_fn. @handler ist
975 * still called in hard interrupt context and has to check
976 * whether the interrupt originates from the device. If yes it
977 * needs to disable the interrupt on the device and return
978 * IRQ_WAKE_THREAD which will wake up the handler thread and run
979 * @thread_fn. This split handler design is necessary to support
982 * Dev_id must be globally unique. Normally the address of the
983 * device data structure is used as the cookie. Since the handler
984 * receives this value it makes sense to use it.
986 * If your interrupt is shared you must pass a non NULL dev_id
987 * as this is required when freeing the interrupt.
991 * IRQF_SHARED Interrupt is shared
992 * IRQF_DISABLED Disable local interrupts while processing
993 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
994 * IRQF_TRIGGER_* Specify active edge(s) or level
997 int request_threaded_irq(unsigned int irq
, irq_handler_t handler
,
998 irq_handler_t thread_fn
, unsigned long irqflags
,
999 const char *devname
, void *dev_id
)
1001 struct irqaction
*action
;
1002 struct irq_desc
*desc
;
1006 * handle_IRQ_event() always ignores IRQF_DISABLED except for
1007 * the _first_ irqaction (sigh). That can cause oopsing, but
1008 * the behavior is classified as "will not fix" so we need to
1009 * start nudging drivers away from using that idiom.
1011 if ((irqflags
& (IRQF_SHARED
|IRQF_DISABLED
)) ==
1012 (IRQF_SHARED
|IRQF_DISABLED
)) {
1014 "IRQ %d/%s: IRQF_DISABLED is not guaranteed on shared IRQs\n",
1018 #ifdef CONFIG_LOCKDEP
1020 * Lockdep wants atomic interrupt handlers:
1022 irqflags
|= IRQF_DISABLED
;
1025 * Sanity-check: shared interrupts must pass in a real dev-ID,
1026 * otherwise we'll have trouble later trying to figure out
1027 * which interrupt is which (messes up the interrupt freeing
1030 if ((irqflags
& IRQF_SHARED
) && !dev_id
)
1033 desc
= irq_to_desc(irq
);
1037 if (desc
->status
& IRQ_NOREQUEST
)
1043 handler
= irq_default_primary_handler
;
1046 action
= kzalloc(sizeof(struct irqaction
), GFP_KERNEL
);
1050 action
->handler
= handler
;
1051 action
->thread_fn
= thread_fn
;
1052 action
->flags
= irqflags
;
1053 action
->name
= devname
;
1054 action
->dev_id
= dev_id
;
1056 chip_bus_lock(irq
, desc
);
1057 retval
= __setup_irq(irq
, desc
, action
);
1058 chip_bus_sync_unlock(irq
, desc
);
1063 #ifdef CONFIG_DEBUG_SHIRQ
1064 if (irqflags
& IRQF_SHARED
) {
1066 * It's a shared IRQ -- the driver ought to be prepared for it
1067 * to happen immediately, so let's make sure....
1068 * We disable the irq to make sure that a 'real' IRQ doesn't
1069 * run in parallel with our fake.
1071 unsigned long flags
;
1074 local_irq_save(flags
);
1076 handler(irq
, dev_id
);
1078 local_irq_restore(flags
);
1084 EXPORT_SYMBOL(request_threaded_irq
);