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"
20 #ifdef CONFIG_IRQ_FORCED_THREADING
21 __read_mostly
bool force_irqthreads
;
23 static int __init
setup_forced_irqthreads(char *arg
)
25 force_irqthreads
= true;
28 early_param("threadirqs", setup_forced_irqthreads
);
32 * synchronize_irq - wait for pending IRQ handlers (on other CPUs)
33 * @irq: interrupt number to wait for
35 * This function waits for any pending IRQ handlers for this interrupt
36 * to complete before returning. If you use this function while
37 * holding a resource the IRQ handler may need you will deadlock.
39 * This function may be called - with care - from IRQ context.
41 void synchronize_irq(unsigned int irq
)
43 struct irq_desc
*desc
= irq_to_desc(irq
);
53 * Wait until we're out of the critical section. This might
54 * give the wrong answer due to the lack of memory barriers.
56 while (irqd_irq_inprogress(&desc
->irq_data
))
59 /* Ok, that indicated we're done: double-check carefully. */
60 raw_spin_lock_irqsave(&desc
->lock
, flags
);
61 inprogress
= irqd_irq_inprogress(&desc
->irq_data
);
62 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
64 /* Oops, that failed? */
68 * We made sure that no hardirq handler is running. Now verify
69 * that no threaded handlers are active.
71 wait_event(desc
->wait_for_threads
, !atomic_read(&desc
->threads_active
));
73 EXPORT_SYMBOL(synchronize_irq
);
76 cpumask_var_t irq_default_affinity
;
79 * irq_can_set_affinity - Check if the affinity of a given irq can be set
80 * @irq: Interrupt to check
83 int irq_can_set_affinity(unsigned int irq
)
85 struct irq_desc
*desc
= irq_to_desc(irq
);
87 if (!desc
|| !irqd_can_balance(&desc
->irq_data
) ||
88 !desc
->irq_data
.chip
|| !desc
->irq_data
.chip
->irq_set_affinity
)
95 * irq_set_thread_affinity - Notify irq threads to adjust affinity
96 * @desc: irq descriptor which has affitnity changed
98 * We just set IRQTF_AFFINITY and delegate the affinity setting
99 * to the interrupt thread itself. We can not call
100 * set_cpus_allowed_ptr() here as we hold desc->lock and this
101 * code can be called from hard interrupt context.
103 void irq_set_thread_affinity(struct irq_desc
*desc
)
105 struct irqaction
*action
= desc
->action
;
109 set_bit(IRQTF_AFFINITY
, &action
->thread_flags
);
110 action
= action
->next
;
114 #ifdef CONFIG_GENERIC_PENDING_IRQ
115 static inline bool irq_can_move_pcntxt(struct irq_data
*data
)
117 return irqd_can_move_in_process_context(data
);
119 static inline bool irq_move_pending(struct irq_data
*data
)
121 return irqd_is_setaffinity_pending(data
);
124 irq_copy_pending(struct irq_desc
*desc
, const struct cpumask
*mask
)
126 cpumask_copy(desc
->pending_mask
, mask
);
129 irq_get_pending(struct cpumask
*mask
, struct irq_desc
*desc
)
131 cpumask_copy(mask
, desc
->pending_mask
);
134 static inline bool irq_can_move_pcntxt(struct irq_data
*data
) { return true; }
135 static inline bool irq_move_pending(struct irq_data
*data
) { return false; }
137 irq_copy_pending(struct irq_desc
*desc
, const struct cpumask
*mask
) { }
139 irq_get_pending(struct cpumask
*mask
, struct irq_desc
*desc
) { }
142 int __irq_set_affinity_locked(struct irq_data
*data
, const struct cpumask
*mask
)
144 struct irq_chip
*chip
= irq_data_get_irq_chip(data
);
145 struct irq_desc
*desc
= irq_data_to_desc(data
);
148 if (!chip
|| !chip
->irq_set_affinity
)
151 if (irq_can_move_pcntxt(data
)) {
152 ret
= chip
->irq_set_affinity(data
, mask
, false);
154 case IRQ_SET_MASK_OK
:
155 cpumask_copy(data
->affinity
, mask
);
156 case IRQ_SET_MASK_OK_NOCOPY
:
157 irq_set_thread_affinity(desc
);
161 irqd_set_move_pending(data
);
162 irq_copy_pending(desc
, mask
);
165 if (desc
->affinity_notify
) {
166 kref_get(&desc
->affinity_notify
->kref
);
167 schedule_work(&desc
->affinity_notify
->work
);
169 irqd_set(data
, IRQD_AFFINITY_SET
);
175 * irq_set_affinity - Set the irq affinity of a given irq
176 * @irq: Interrupt to set affinity
180 int irq_set_affinity(unsigned int irq
, const struct cpumask
*mask
)
182 struct irq_desc
*desc
= irq_to_desc(irq
);
189 raw_spin_lock_irqsave(&desc
->lock
, flags
);
190 ret
= __irq_set_affinity_locked(irq_desc_get_irq_data(desc
), mask
);
191 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
195 int irq_set_affinity_hint(unsigned int irq
, const struct cpumask
*m
)
198 struct irq_desc
*desc
= irq_get_desc_lock(irq
, &flags
);
202 desc
->affinity_hint
= m
;
203 irq_put_desc_unlock(desc
, flags
);
206 EXPORT_SYMBOL_GPL(irq_set_affinity_hint
);
208 static void irq_affinity_notify(struct work_struct
*work
)
210 struct irq_affinity_notify
*notify
=
211 container_of(work
, struct irq_affinity_notify
, work
);
212 struct irq_desc
*desc
= irq_to_desc(notify
->irq
);
213 cpumask_var_t cpumask
;
216 if (!desc
|| !alloc_cpumask_var(&cpumask
, GFP_KERNEL
))
219 raw_spin_lock_irqsave(&desc
->lock
, flags
);
220 if (irq_move_pending(&desc
->irq_data
))
221 irq_get_pending(cpumask
, desc
);
223 cpumask_copy(cpumask
, desc
->irq_data
.affinity
);
224 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
226 notify
->notify(notify
, cpumask
);
228 free_cpumask_var(cpumask
);
230 kref_put(¬ify
->kref
, notify
->release
);
234 * irq_set_affinity_notifier - control notification of IRQ affinity changes
235 * @irq: Interrupt for which to enable/disable notification
236 * @notify: Context for notification, or %NULL to disable
237 * notification. Function pointers must be initialised;
238 * the other fields will be initialised by this function.
240 * Must be called in process context. Notification may only be enabled
241 * after the IRQ is allocated and must be disabled before the IRQ is
242 * freed using free_irq().
245 irq_set_affinity_notifier(unsigned int irq
, struct irq_affinity_notify
*notify
)
247 struct irq_desc
*desc
= irq_to_desc(irq
);
248 struct irq_affinity_notify
*old_notify
;
251 /* The release function is promised process context */
257 /* Complete initialisation of *notify */
260 kref_init(¬ify
->kref
);
261 INIT_WORK(¬ify
->work
, irq_affinity_notify
);
264 raw_spin_lock_irqsave(&desc
->lock
, flags
);
265 old_notify
= desc
->affinity_notify
;
266 desc
->affinity_notify
= notify
;
267 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
270 kref_put(&old_notify
->kref
, old_notify
->release
);
274 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier
);
276 #ifndef CONFIG_AUTO_IRQ_AFFINITY
278 * Generic version of the affinity autoselector.
281 setup_affinity(unsigned int irq
, struct irq_desc
*desc
, struct cpumask
*mask
)
283 struct irq_chip
*chip
= irq_desc_get_chip(desc
);
284 struct cpumask
*set
= irq_default_affinity
;
287 /* Excludes PER_CPU and NO_BALANCE interrupts */
288 if (!irq_can_set_affinity(irq
))
292 * Preserve an userspace affinity setup, but make sure that
293 * one of the targets is online.
295 if (irqd_has_set(&desc
->irq_data
, IRQD_AFFINITY_SET
)) {
296 if (cpumask_intersects(desc
->irq_data
.affinity
,
298 set
= desc
->irq_data
.affinity
;
300 irqd_clear(&desc
->irq_data
, IRQD_AFFINITY_SET
);
303 cpumask_and(mask
, cpu_online_mask
, set
);
304 ret
= chip
->irq_set_affinity(&desc
->irq_data
, mask
, false);
306 case IRQ_SET_MASK_OK
:
307 cpumask_copy(desc
->irq_data
.affinity
, mask
);
308 case IRQ_SET_MASK_OK_NOCOPY
:
309 irq_set_thread_affinity(desc
);
315 setup_affinity(unsigned int irq
, struct irq_desc
*d
, struct cpumask
*mask
)
317 return irq_select_affinity(irq
);
322 * Called when affinity is set via /proc/irq
324 int irq_select_affinity_usr(unsigned int irq
, struct cpumask
*mask
)
326 struct irq_desc
*desc
= irq_to_desc(irq
);
330 raw_spin_lock_irqsave(&desc
->lock
, flags
);
331 ret
= setup_affinity(irq
, desc
, mask
);
332 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
338 setup_affinity(unsigned int irq
, struct irq_desc
*desc
, struct cpumask
*mask
)
344 void __disable_irq(struct irq_desc
*desc
, unsigned int irq
, bool suspend
)
347 if (!desc
->action
|| (desc
->action
->flags
& IRQF_NO_SUSPEND
))
349 desc
->istate
|= IRQS_SUSPENDED
;
356 static int __disable_irq_nosync(unsigned int irq
)
359 struct irq_desc
*desc
= irq_get_desc_buslock(irq
, &flags
);
363 __disable_irq(desc
, irq
, false);
364 irq_put_desc_busunlock(desc
, flags
);
369 * disable_irq_nosync - disable an irq without waiting
370 * @irq: Interrupt to disable
372 * Disable the selected interrupt line. Disables and Enables are
374 * Unlike disable_irq(), this function does not ensure existing
375 * instances of the IRQ handler have completed before returning.
377 * This function may be called from IRQ context.
379 void disable_irq_nosync(unsigned int irq
)
381 __disable_irq_nosync(irq
);
383 EXPORT_SYMBOL(disable_irq_nosync
);
386 * disable_irq - disable an irq and wait for completion
387 * @irq: Interrupt to disable
389 * Disable the selected interrupt line. Enables and Disables are
391 * This function waits for any pending IRQ handlers for this interrupt
392 * to complete before returning. If you use this function while
393 * holding a resource the IRQ handler may need you will deadlock.
395 * This function may be called - with care - from IRQ context.
397 void disable_irq(unsigned int irq
)
399 if (!__disable_irq_nosync(irq
))
400 synchronize_irq(irq
);
402 EXPORT_SYMBOL(disable_irq
);
404 void __enable_irq(struct irq_desc
*desc
, unsigned int irq
, bool resume
)
407 if (!(desc
->istate
& IRQS_SUSPENDED
)) {
410 if (!(desc
->action
->flags
& IRQF_FORCE_RESUME
))
412 /* Pretend that it got disabled ! */
415 desc
->istate
&= ~IRQS_SUSPENDED
;
418 switch (desc
->depth
) {
421 WARN(1, KERN_WARNING
"Unbalanced enable for IRQ %d\n", irq
);
424 if (desc
->istate
& IRQS_SUSPENDED
)
426 /* Prevent probing on this irq: */
427 irq_settings_set_noprobe(desc
);
429 check_irq_resend(desc
, irq
);
438 * enable_irq - enable handling of an irq
439 * @irq: Interrupt to enable
441 * Undoes the effect of one call to disable_irq(). If this
442 * matches the last disable, processing of interrupts on this
443 * IRQ line is re-enabled.
445 * This function may be called from IRQ context only when
446 * desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
448 void enable_irq(unsigned int irq
)
451 struct irq_desc
*desc
= irq_get_desc_buslock(irq
, &flags
);
455 if (WARN(!desc
->irq_data
.chip
,
456 KERN_ERR
"enable_irq before setup/request_irq: irq %u\n", irq
))
459 __enable_irq(desc
, irq
, false);
461 irq_put_desc_busunlock(desc
, flags
);
463 EXPORT_SYMBOL(enable_irq
);
465 static int set_irq_wake_real(unsigned int irq
, unsigned int on
)
467 struct irq_desc
*desc
= irq_to_desc(irq
);
470 if (desc
->irq_data
.chip
->irq_set_wake
)
471 ret
= desc
->irq_data
.chip
->irq_set_wake(&desc
->irq_data
, on
);
477 * irq_set_irq_wake - control irq power management wakeup
478 * @irq: interrupt to control
479 * @on: enable/disable power management wakeup
481 * Enable/disable power management wakeup mode, which is
482 * disabled by default. Enables and disables must match,
483 * just as they match for non-wakeup mode support.
485 * Wakeup mode lets this IRQ wake the system from sleep
486 * states like "suspend to RAM".
488 int irq_set_irq_wake(unsigned int irq
, unsigned int on
)
491 struct irq_desc
*desc
= irq_get_desc_buslock(irq
, &flags
);
497 /* wakeup-capable irqs can be shared between drivers that
498 * don't need to have the same sleep mode behaviors.
501 if (desc
->wake_depth
++ == 0) {
502 ret
= set_irq_wake_real(irq
, on
);
504 desc
->wake_depth
= 0;
506 irqd_set(&desc
->irq_data
, IRQD_WAKEUP_STATE
);
509 if (desc
->wake_depth
== 0) {
510 WARN(1, "Unbalanced IRQ %d wake disable\n", irq
);
511 } else if (--desc
->wake_depth
== 0) {
512 ret
= set_irq_wake_real(irq
, on
);
514 desc
->wake_depth
= 1;
516 irqd_clear(&desc
->irq_data
, IRQD_WAKEUP_STATE
);
519 irq_put_desc_busunlock(desc
, flags
);
522 EXPORT_SYMBOL(irq_set_irq_wake
);
525 * Internal function that tells the architecture code whether a
526 * particular irq has been exclusively allocated or is available
529 int can_request_irq(unsigned int irq
, unsigned long irqflags
)
532 struct irq_desc
*desc
= irq_get_desc_lock(irq
, &flags
);
538 if (irq_settings_can_request(desc
)) {
540 if (irqflags
& desc
->action
->flags
& IRQF_SHARED
)
543 irq_put_desc_unlock(desc
, flags
);
547 int __irq_set_trigger(struct irq_desc
*desc
, unsigned int irq
,
550 struct irq_chip
*chip
= desc
->irq_data
.chip
;
553 if (!chip
|| !chip
->irq_set_type
) {
555 * IRQF_TRIGGER_* but the PIC does not support multiple
558 pr_debug("No set_type function for IRQ %d (%s)\n", irq
,
559 chip
? (chip
->name
? : "unknown") : "unknown");
563 flags
&= IRQ_TYPE_SENSE_MASK
;
565 if (chip
->flags
& IRQCHIP_SET_TYPE_MASKED
) {
566 if (!irqd_irq_masked(&desc
->irq_data
))
568 if (!irqd_irq_disabled(&desc
->irq_data
))
572 /* caller masked out all except trigger mode flags */
573 ret
= chip
->irq_set_type(&desc
->irq_data
, flags
);
576 case IRQ_SET_MASK_OK
:
577 irqd_clear(&desc
->irq_data
, IRQD_TRIGGER_MASK
);
578 irqd_set(&desc
->irq_data
, flags
);
580 case IRQ_SET_MASK_OK_NOCOPY
:
581 flags
= irqd_get_trigger_type(&desc
->irq_data
);
582 irq_settings_set_trigger_mask(desc
, flags
);
583 irqd_clear(&desc
->irq_data
, IRQD_LEVEL
);
584 irq_settings_clr_level(desc
);
585 if (flags
& IRQ_TYPE_LEVEL_MASK
) {
586 irq_settings_set_level(desc
);
587 irqd_set(&desc
->irq_data
, IRQD_LEVEL
);
593 pr_err("setting trigger mode %lu for irq %u failed (%pF)\n",
594 flags
, irq
, chip
->irq_set_type
);
602 * Default primary interrupt handler for threaded interrupts. Is
603 * assigned as primary handler when request_threaded_irq is called
604 * with handler == NULL. Useful for oneshot interrupts.
606 static irqreturn_t
irq_default_primary_handler(int irq
, void *dev_id
)
608 return IRQ_WAKE_THREAD
;
612 * Primary handler for nested threaded interrupts. Should never be
615 static irqreturn_t
irq_nested_primary_handler(int irq
, void *dev_id
)
617 WARN(1, "Primary handler called for nested irq %d\n", irq
);
621 static int irq_wait_for_interrupt(struct irqaction
*action
)
623 while (!kthread_should_stop()) {
624 set_current_state(TASK_INTERRUPTIBLE
);
626 if (test_and_clear_bit(IRQTF_RUNTHREAD
,
627 &action
->thread_flags
)) {
628 __set_current_state(TASK_RUNNING
);
637 * Oneshot interrupts keep the irq line masked until the threaded
638 * handler finished. unmask if the interrupt has not been disabled and
641 static void irq_finalize_oneshot(struct irq_desc
*desc
,
642 struct irqaction
*action
, bool force
)
644 if (!(desc
->istate
& IRQS_ONESHOT
))
648 raw_spin_lock_irq(&desc
->lock
);
651 * Implausible though it may be we need to protect us against
652 * the following scenario:
654 * The thread is faster done than the hard interrupt handler
655 * on the other CPU. If we unmask the irq line then the
656 * interrupt can come in again and masks the line, leaves due
657 * to IRQS_INPROGRESS and the irq line is masked forever.
659 * This also serializes the state of shared oneshot handlers
660 * versus "desc->threads_onehsot |= action->thread_mask;" in
661 * irq_wake_thread(). See the comment there which explains the
664 if (unlikely(irqd_irq_inprogress(&desc
->irq_data
))) {
665 raw_spin_unlock_irq(&desc
->lock
);
666 chip_bus_sync_unlock(desc
);
672 * Now check again, whether the thread should run. Otherwise
673 * we would clear the threads_oneshot bit of this thread which
676 if (!force
&& test_bit(IRQTF_RUNTHREAD
, &action
->thread_flags
))
679 desc
->threads_oneshot
&= ~action
->thread_mask
;
681 if (!desc
->threads_oneshot
&& !irqd_irq_disabled(&desc
->irq_data
) &&
682 irqd_irq_masked(&desc
->irq_data
))
686 raw_spin_unlock_irq(&desc
->lock
);
687 chip_bus_sync_unlock(desc
);
692 * Check whether we need to chasnge the affinity of the interrupt thread.
695 irq_thread_check_affinity(struct irq_desc
*desc
, struct irqaction
*action
)
699 if (!test_and_clear_bit(IRQTF_AFFINITY
, &action
->thread_flags
))
703 * In case we are out of memory we set IRQTF_AFFINITY again and
704 * try again next time
706 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
)) {
707 set_bit(IRQTF_AFFINITY
, &action
->thread_flags
);
711 raw_spin_lock_irq(&desc
->lock
);
712 cpumask_copy(mask
, desc
->irq_data
.affinity
);
713 raw_spin_unlock_irq(&desc
->lock
);
715 set_cpus_allowed_ptr(current
, mask
);
716 free_cpumask_var(mask
);
720 irq_thread_check_affinity(struct irq_desc
*desc
, struct irqaction
*action
) { }
724 * Interrupts which are not explicitely requested as threaded
725 * interrupts rely on the implicit bh/preempt disable of the hard irq
726 * context. So we need to disable bh here to avoid deadlocks and other
730 irq_forced_thread_fn(struct irq_desc
*desc
, struct irqaction
*action
)
735 ret
= action
->thread_fn(action
->irq
, action
->dev_id
);
736 irq_finalize_oneshot(desc
, action
, false);
742 * Interrupts explicitely requested as threaded interupts want to be
743 * preemtible - many of them need to sleep and wait for slow busses to
746 static irqreturn_t
irq_thread_fn(struct irq_desc
*desc
,
747 struct irqaction
*action
)
751 ret
= action
->thread_fn(action
->irq
, action
->dev_id
);
752 irq_finalize_oneshot(desc
, action
, false);
757 * Interrupt handler thread
759 static int irq_thread(void *data
)
761 static const struct sched_param param
= {
762 .sched_priority
= MAX_USER_RT_PRIO
/2,
764 struct irqaction
*action
= data
;
765 struct irq_desc
*desc
= irq_to_desc(action
->irq
);
766 irqreturn_t (*handler_fn
)(struct irq_desc
*desc
,
767 struct irqaction
*action
);
770 if (force_irqthreads
& test_bit(IRQTF_FORCED_THREAD
,
771 &action
->thread_flags
))
772 handler_fn
= irq_forced_thread_fn
;
774 handler_fn
= irq_thread_fn
;
776 sched_setscheduler(current
, SCHED_FIFO
, ¶m
);
777 current
->irqaction
= action
;
779 while (!irq_wait_for_interrupt(action
)) {
781 irq_thread_check_affinity(desc
, action
);
783 atomic_inc(&desc
->threads_active
);
785 raw_spin_lock_irq(&desc
->lock
);
786 if (unlikely(irqd_irq_disabled(&desc
->irq_data
))) {
788 * CHECKME: We might need a dedicated
789 * IRQ_THREAD_PENDING flag here, which
790 * retriggers the thread in check_irq_resend()
791 * but AFAICT IRQS_PENDING should be fine as it
792 * retriggers the interrupt itself --- tglx
794 desc
->istate
|= IRQS_PENDING
;
795 raw_spin_unlock_irq(&desc
->lock
);
797 irqreturn_t action_ret
;
799 raw_spin_unlock_irq(&desc
->lock
);
800 action_ret
= handler_fn(desc
, action
);
802 note_interrupt(action
->irq
, desc
, action_ret
);
805 wake
= atomic_dec_and_test(&desc
->threads_active
);
807 if (wake
&& waitqueue_active(&desc
->wait_for_threads
))
808 wake_up(&desc
->wait_for_threads
);
811 /* Prevent a stale desc->threads_oneshot */
812 irq_finalize_oneshot(desc
, action
, true);
815 * Clear irqaction. Otherwise exit_irq_thread() would make
816 * fuzz about an active irq thread going into nirvana.
818 current
->irqaction
= NULL
;
823 * Called from do_exit()
825 void exit_irq_thread(void)
827 struct task_struct
*tsk
= current
;
828 struct irq_desc
*desc
;
834 "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
835 tsk
->comm
? tsk
->comm
: "", tsk
->pid
, tsk
->irqaction
->irq
);
837 desc
= irq_to_desc(tsk
->irqaction
->irq
);
840 * Prevent a stale desc->threads_oneshot. Must be called
841 * before setting the IRQTF_DIED flag.
843 irq_finalize_oneshot(desc
, tsk
->irqaction
, true);
846 * Set the THREAD DIED flag to prevent further wakeups of the
847 * soon to be gone threaded handler.
849 set_bit(IRQTF_DIED
, &tsk
->irqaction
->flags
);
852 static void irq_setup_forced_threading(struct irqaction
*new)
854 if (!force_irqthreads
)
856 if (new->flags
& (IRQF_NO_THREAD
| IRQF_PERCPU
| IRQF_ONESHOT
))
859 new->flags
|= IRQF_ONESHOT
;
861 if (!new->thread_fn
) {
862 set_bit(IRQTF_FORCED_THREAD
, &new->thread_flags
);
863 new->thread_fn
= new->handler
;
864 new->handler
= irq_default_primary_handler
;
869 * Internal function to register an irqaction - typically used to
870 * allocate special interrupts that are part of the architecture.
873 __setup_irq(unsigned int irq
, struct irq_desc
*desc
, struct irqaction
*new)
875 struct irqaction
*old
, **old_ptr
;
876 const char *old_name
= NULL
;
877 unsigned long flags
, thread_mask
= 0;
878 int ret
, nested
, shared
= 0;
884 if (desc
->irq_data
.chip
== &no_irq_chip
)
887 * Some drivers like serial.c use request_irq() heavily,
888 * so we have to be careful not to interfere with a
891 if (new->flags
& IRQF_SAMPLE_RANDOM
) {
893 * This function might sleep, we want to call it first,
894 * outside of the atomic block.
895 * Yes, this might clear the entropy pool if the wrong
896 * driver is attempted to be loaded, without actually
897 * installing a new handler, but is this really a problem,
898 * only the sysadmin is able to do this.
900 rand_initialize_irq(irq
);
904 * Check whether the interrupt nests into another interrupt
907 nested
= irq_settings_is_nested_thread(desc
);
912 * Replace the primary handler which was provided from
913 * the driver for non nested interrupt handling by the
914 * dummy function which warns when called.
916 new->handler
= irq_nested_primary_handler
;
918 if (irq_settings_can_thread(desc
))
919 irq_setup_forced_threading(new);
923 * Create a handler thread when a thread function is supplied
924 * and the interrupt does not nest into another interrupt
927 if (new->thread_fn
&& !nested
) {
928 struct task_struct
*t
;
930 t
= kthread_create(irq_thread
, new, "irq/%d-%s", irq
,
935 * We keep the reference to the task struct even if
936 * the thread dies to avoid that the interrupt code
937 * references an already freed task_struct.
943 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
)) {
949 * The following block of code has to be executed atomically
951 raw_spin_lock_irqsave(&desc
->lock
, flags
);
952 old_ptr
= &desc
->action
;
956 * Can't share interrupts unless both agree to and are
957 * the same type (level, edge, polarity). So both flag
958 * fields must have IRQF_SHARED set and the bits which
959 * set the trigger type must match. Also all must
962 if (!((old
->flags
& new->flags
) & IRQF_SHARED
) ||
963 ((old
->flags
^ new->flags
) & IRQF_TRIGGER_MASK
) ||
964 ((old
->flags
^ new->flags
) & IRQF_ONESHOT
)) {
965 old_name
= old
->name
;
969 /* All handlers must agree on per-cpuness */
970 if ((old
->flags
& IRQF_PERCPU
) !=
971 (new->flags
& IRQF_PERCPU
))
974 /* add new interrupt at end of irq queue */
976 thread_mask
|= old
->thread_mask
;
977 old_ptr
= &old
->next
;
984 * Setup the thread mask for this irqaction. Unlikely to have
985 * 32 resp 64 irqs sharing one line, but who knows.
987 if (new->flags
& IRQF_ONESHOT
&& thread_mask
== ~0UL) {
991 new->thread_mask
= 1 << ffz(thread_mask
);
994 init_waitqueue_head(&desc
->wait_for_threads
);
996 /* Setup the type (level, edge polarity) if configured: */
997 if (new->flags
& IRQF_TRIGGER_MASK
) {
998 ret
= __irq_set_trigger(desc
, irq
,
999 new->flags
& IRQF_TRIGGER_MASK
);
1005 desc
->istate
&= ~(IRQS_AUTODETECT
| IRQS_SPURIOUS_DISABLED
| \
1006 IRQS_ONESHOT
| IRQS_WAITING
);
1007 irqd_clear(&desc
->irq_data
, IRQD_IRQ_INPROGRESS
);
1009 if (new->flags
& IRQF_PERCPU
) {
1010 irqd_set(&desc
->irq_data
, IRQD_PER_CPU
);
1011 irq_settings_set_per_cpu(desc
);
1014 if (new->flags
& IRQF_ONESHOT
)
1015 desc
->istate
|= IRQS_ONESHOT
;
1017 if (irq_settings_can_autoenable(desc
))
1020 /* Undo nested disables: */
1023 /* Exclude IRQ from balancing if requested */
1024 if (new->flags
& IRQF_NOBALANCING
) {
1025 irq_settings_set_no_balancing(desc
);
1026 irqd_set(&desc
->irq_data
, IRQD_NO_BALANCING
);
1029 /* Set default affinity mask once everything is setup */
1030 setup_affinity(irq
, desc
, mask
);
1032 } else if (new->flags
& IRQF_TRIGGER_MASK
) {
1033 unsigned int nmsk
= new->flags
& IRQF_TRIGGER_MASK
;
1034 unsigned int omsk
= irq_settings_get_trigger_mask(desc
);
1037 /* hope the handler works with current trigger mode */
1038 pr_warning("IRQ %d uses trigger mode %u; requested %u\n",
1045 /* Reset broken irq detection when installing new handler */
1046 desc
->irq_count
= 0;
1047 desc
->irqs_unhandled
= 0;
1050 * Check whether we disabled the irq via the spurious handler
1051 * before. Reenable it and give it another chance.
1053 if (shared
&& (desc
->istate
& IRQS_SPURIOUS_DISABLED
)) {
1054 desc
->istate
&= ~IRQS_SPURIOUS_DISABLED
;
1055 __enable_irq(desc
, irq
, false);
1058 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
1061 * Strictly no need to wake it up, but hung_task complains
1062 * when no hard interrupt wakes the thread up.
1065 wake_up_process(new->thread
);
1067 register_irq_proc(irq
, desc
);
1069 register_handler_proc(irq
, new);
1070 free_cpumask_var(mask
);
1075 #ifdef CONFIG_DEBUG_SHIRQ
1076 if (!(new->flags
& IRQF_PROBE_SHARED
)) {
1077 printk(KERN_ERR
"IRQ handler type mismatch for IRQ %d\n", irq
);
1079 printk(KERN_ERR
"current handler: %s\n", old_name
);
1086 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
1087 free_cpumask_var(mask
);
1091 struct task_struct
*t
= new->thread
;
1094 if (likely(!test_bit(IRQTF_DIED
, &new->thread_flags
)))
1102 * setup_irq - setup an interrupt
1103 * @irq: Interrupt line to setup
1104 * @act: irqaction for the interrupt
1106 * Used to statically setup interrupts in the early boot process.
1108 int setup_irq(unsigned int irq
, struct irqaction
*act
)
1111 struct irq_desc
*desc
= irq_to_desc(irq
);
1113 chip_bus_lock(desc
);
1114 retval
= __setup_irq(irq
, desc
, act
);
1115 chip_bus_sync_unlock(desc
);
1119 EXPORT_SYMBOL_GPL(setup_irq
);
1122 * Internal function to unregister an irqaction - used to free
1123 * regular and special interrupts that are part of the architecture.
1125 static struct irqaction
*__free_irq(unsigned int irq
, void *dev_id
)
1127 struct irq_desc
*desc
= irq_to_desc(irq
);
1128 struct irqaction
*action
, **action_ptr
;
1129 unsigned long flags
;
1131 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq
);
1136 raw_spin_lock_irqsave(&desc
->lock
, flags
);
1139 * There can be multiple actions per IRQ descriptor, find the right
1140 * one based on the dev_id:
1142 action_ptr
= &desc
->action
;
1144 action
= *action_ptr
;
1147 WARN(1, "Trying to free already-free IRQ %d\n", irq
);
1148 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
1153 if (action
->dev_id
== dev_id
)
1155 action_ptr
= &action
->next
;
1158 /* Found it - now remove it from the list of entries: */
1159 *action_ptr
= action
->next
;
1161 /* Currently used only by UML, might disappear one day: */
1162 #ifdef CONFIG_IRQ_RELEASE_METHOD
1163 if (desc
->irq_data
.chip
->release
)
1164 desc
->irq_data
.chip
->release(irq
, dev_id
);
1167 /* If this was the last handler, shut down the IRQ line: */
1172 /* make sure affinity_hint is cleaned up */
1173 if (WARN_ON_ONCE(desc
->affinity_hint
))
1174 desc
->affinity_hint
= NULL
;
1177 raw_spin_unlock_irqrestore(&desc
->lock
, flags
);
1179 unregister_handler_proc(irq
, action
);
1181 /* Make sure it's not being used on another CPU: */
1182 synchronize_irq(irq
);
1184 #ifdef CONFIG_DEBUG_SHIRQ
1186 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1187 * event to happen even now it's being freed, so let's make sure that
1188 * is so by doing an extra call to the handler ....
1190 * ( We do this after actually deregistering it, to make sure that a
1191 * 'real' IRQ doesn't run in * parallel with our fake. )
1193 if (action
->flags
& IRQF_SHARED
) {
1194 local_irq_save(flags
);
1195 action
->handler(irq
, dev_id
);
1196 local_irq_restore(flags
);
1200 if (action
->thread
) {
1201 if (!test_bit(IRQTF_DIED
, &action
->thread_flags
))
1202 kthread_stop(action
->thread
);
1203 put_task_struct(action
->thread
);
1210 * remove_irq - free an interrupt
1211 * @irq: Interrupt line to free
1212 * @act: irqaction for the interrupt
1214 * Used to remove interrupts statically setup by the early boot process.
1216 void remove_irq(unsigned int irq
, struct irqaction
*act
)
1218 __free_irq(irq
, act
->dev_id
);
1220 EXPORT_SYMBOL_GPL(remove_irq
);
1223 * free_irq - free an interrupt allocated with request_irq
1224 * @irq: Interrupt line to free
1225 * @dev_id: Device identity to free
1227 * Remove an interrupt handler. The handler is removed and if the
1228 * interrupt line is no longer in use by any driver it is disabled.
1229 * On a shared IRQ the caller must ensure the interrupt is disabled
1230 * on the card it drives before calling this function. The function
1231 * does not return until any executing interrupts for this IRQ
1234 * This function must not be called from interrupt context.
1236 void free_irq(unsigned int irq
, void *dev_id
)
1238 struct irq_desc
*desc
= irq_to_desc(irq
);
1244 if (WARN_ON(desc
->affinity_notify
))
1245 desc
->affinity_notify
= NULL
;
1248 chip_bus_lock(desc
);
1249 kfree(__free_irq(irq
, dev_id
));
1250 chip_bus_sync_unlock(desc
);
1252 EXPORT_SYMBOL(free_irq
);
1255 * request_threaded_irq - allocate an interrupt line
1256 * @irq: Interrupt line to allocate
1257 * @handler: Function to be called when the IRQ occurs.
1258 * Primary handler for threaded interrupts
1259 * If NULL and thread_fn != NULL the default
1260 * primary handler is installed
1261 * @thread_fn: Function called from the irq handler thread
1262 * If NULL, no irq thread is created
1263 * @irqflags: Interrupt type flags
1264 * @devname: An ascii name for the claiming device
1265 * @dev_id: A cookie passed back to the handler function
1267 * This call allocates interrupt resources and enables the
1268 * interrupt line and IRQ handling. From the point this
1269 * call is made your handler function may be invoked. Since
1270 * your handler function must clear any interrupt the board
1271 * raises, you must take care both to initialise your hardware
1272 * and to set up the interrupt handler in the right order.
1274 * If you want to set up a threaded irq handler for your device
1275 * then you need to supply @handler and @thread_fn. @handler ist
1276 * still called in hard interrupt context and has to check
1277 * whether the interrupt originates from the device. If yes it
1278 * needs to disable the interrupt on the device and return
1279 * IRQ_WAKE_THREAD which will wake up the handler thread and run
1280 * @thread_fn. This split handler design is necessary to support
1281 * shared interrupts.
1283 * Dev_id must be globally unique. Normally the address of the
1284 * device data structure is used as the cookie. Since the handler
1285 * receives this value it makes sense to use it.
1287 * If your interrupt is shared you must pass a non NULL dev_id
1288 * as this is required when freeing the interrupt.
1292 * IRQF_SHARED Interrupt is shared
1293 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
1294 * IRQF_TRIGGER_* Specify active edge(s) or level
1297 int request_threaded_irq(unsigned int irq
, irq_handler_t handler
,
1298 irq_handler_t thread_fn
, unsigned long irqflags
,
1299 const char *devname
, void *dev_id
)
1301 struct irqaction
*action
;
1302 struct irq_desc
*desc
;
1306 * Sanity-check: shared interrupts must pass in a real dev-ID,
1307 * otherwise we'll have trouble later trying to figure out
1308 * which interrupt is which (messes up the interrupt freeing
1311 if ((irqflags
& IRQF_SHARED
) && !dev_id
)
1314 desc
= irq_to_desc(irq
);
1318 if (!irq_settings_can_request(desc
))
1324 handler
= irq_default_primary_handler
;
1327 action
= kzalloc(sizeof(struct irqaction
), GFP_KERNEL
);
1331 action
->handler
= handler
;
1332 action
->thread_fn
= thread_fn
;
1333 action
->flags
= irqflags
;
1334 action
->name
= devname
;
1335 action
->dev_id
= dev_id
;
1337 chip_bus_lock(desc
);
1338 retval
= __setup_irq(irq
, desc
, action
);
1339 chip_bus_sync_unlock(desc
);
1344 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1345 if (!retval
&& (irqflags
& IRQF_SHARED
)) {
1347 * It's a shared IRQ -- the driver ought to be prepared for it
1348 * to happen immediately, so let's make sure....
1349 * We disable the irq to make sure that a 'real' IRQ doesn't
1350 * run in parallel with our fake.
1352 unsigned long flags
;
1355 local_irq_save(flags
);
1357 handler(irq
, dev_id
);
1359 local_irq_restore(flags
);
1365 EXPORT_SYMBOL(request_threaded_irq
);
1368 * request_any_context_irq - allocate an interrupt line
1369 * @irq: Interrupt line to allocate
1370 * @handler: Function to be called when the IRQ occurs.
1371 * Threaded handler for threaded interrupts.
1372 * @flags: Interrupt type flags
1373 * @name: An ascii name for the claiming device
1374 * @dev_id: A cookie passed back to the handler function
1376 * This call allocates interrupt resources and enables the
1377 * interrupt line and IRQ handling. It selects either a
1378 * hardirq or threaded handling method depending on the
1381 * On failure, it returns a negative value. On success,
1382 * it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1384 int request_any_context_irq(unsigned int irq
, irq_handler_t handler
,
1385 unsigned long flags
, const char *name
, void *dev_id
)
1387 struct irq_desc
*desc
= irq_to_desc(irq
);
1393 if (irq_settings_is_nested_thread(desc
)) {
1394 ret
= request_threaded_irq(irq
, NULL
, handler
,
1395 flags
, name
, dev_id
);
1396 return !ret
? IRQC_IS_NESTED
: ret
;
1399 ret
= request_irq(irq
, handler
, flags
, name
, dev_id
);
1400 return !ret
? IRQC_IS_HARDIRQ
: ret
;
1402 EXPORT_SYMBOL_GPL(request_any_context_irq
);