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, IRQ_GET_DESC_CHECK_GLOBAL);
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;
285 int ret, node = desc->irq_data.node;
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 if (node != NUMA_NO_NODE) {
305 const struct cpumask *nodemask = cpumask_of_node(node);
307 /* make sure at least one of the cpus in nodemask is online */
308 if (cpumask_intersects(mask, nodemask))
309 cpumask_and(mask, mask, nodemask);
311 ret = chip->irq_set_affinity(&desc->irq_data, mask, false);
313 case IRQ_SET_MASK_OK:
314 cpumask_copy(desc->irq_data.affinity, mask);
315 case IRQ_SET_MASK_OK_NOCOPY:
316 irq_set_thread_affinity(desc);
322 setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
324 return irq_select_affinity(irq);
329 * Called when affinity is set via /proc/irq
331 int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
333 struct irq_desc *desc = irq_to_desc(irq);
337 raw_spin_lock_irqsave(&desc->lock, flags);
338 ret = setup_affinity(irq, desc, mask);
339 raw_spin_unlock_irqrestore(&desc->lock, flags);
345 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
351 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
354 if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
356 desc->istate |= IRQS_SUSPENDED;
363 static int __disable_irq_nosync(unsigned int irq)
366 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
370 __disable_irq(desc, irq, false);
371 irq_put_desc_busunlock(desc, flags);
376 * disable_irq_nosync - disable an irq without waiting
377 * @irq: Interrupt to disable
379 * Disable the selected interrupt line. Disables and Enables are
381 * Unlike disable_irq(), this function does not ensure existing
382 * instances of the IRQ handler have completed before returning.
384 * This function may be called from IRQ context.
386 void disable_irq_nosync(unsigned int irq)
388 __disable_irq_nosync(irq);
390 EXPORT_SYMBOL(disable_irq_nosync);
393 * disable_irq - disable an irq and wait for completion
394 * @irq: Interrupt to disable
396 * Disable the selected interrupt line. Enables and Disables are
398 * This function waits for any pending IRQ handlers for this interrupt
399 * to complete before returning. If you use this function while
400 * holding a resource the IRQ handler may need you will deadlock.
402 * This function may be called - with care - from IRQ context.
404 void disable_irq(unsigned int irq)
406 if (!__disable_irq_nosync(irq))
407 synchronize_irq(irq);
409 EXPORT_SYMBOL(disable_irq);
411 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
414 if (!(desc->istate & IRQS_SUSPENDED)) {
417 if (!(desc->action->flags & IRQF_FORCE_RESUME))
419 /* Pretend that it got disabled ! */
422 desc->istate &= ~IRQS_SUSPENDED;
425 switch (desc->depth) {
428 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
431 if (desc->istate & IRQS_SUSPENDED)
433 /* Prevent probing on this irq: */
434 irq_settings_set_noprobe(desc);
436 check_irq_resend(desc, irq);
445 * enable_irq - enable handling of an irq
446 * @irq: Interrupt to enable
448 * Undoes the effect of one call to disable_irq(). If this
449 * matches the last disable, processing of interrupts on this
450 * IRQ line is re-enabled.
452 * This function may be called from IRQ context only when
453 * desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
455 void enable_irq(unsigned int irq)
458 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
462 if (WARN(!desc->irq_data.chip,
463 KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
466 __enable_irq(desc, irq, false);
468 irq_put_desc_busunlock(desc, flags);
470 EXPORT_SYMBOL(enable_irq);
472 static int set_irq_wake_real(unsigned int irq, unsigned int on)
474 struct irq_desc *desc = irq_to_desc(irq);
477 if (irq_desc_get_chip(desc)->flags & IRQCHIP_SKIP_SET_WAKE)
480 if (desc->irq_data.chip->irq_set_wake)
481 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
487 * irq_set_irq_wake - control irq power management wakeup
488 * @irq: interrupt to control
489 * @on: enable/disable power management wakeup
491 * Enable/disable power management wakeup mode, which is
492 * disabled by default. Enables and disables must match,
493 * just as they match for non-wakeup mode support.
495 * Wakeup mode lets this IRQ wake the system from sleep
496 * states like "suspend to RAM".
498 int irq_set_irq_wake(unsigned int irq, unsigned int on)
501 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
507 /* wakeup-capable irqs can be shared between drivers that
508 * don't need to have the same sleep mode behaviors.
511 if (desc->wake_depth++ == 0) {
512 ret = set_irq_wake_real(irq, on);
514 desc->wake_depth = 0;
516 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
519 if (desc->wake_depth == 0) {
520 WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
521 } else if (--desc->wake_depth == 0) {
522 ret = set_irq_wake_real(irq, on);
524 desc->wake_depth = 1;
526 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
529 irq_put_desc_busunlock(desc, flags);
532 EXPORT_SYMBOL(irq_set_irq_wake);
535 * Internal function that tells the architecture code whether a
536 * particular irq has been exclusively allocated or is available
539 int can_request_irq(unsigned int irq, unsigned long irqflags)
542 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
548 if (irq_settings_can_request(desc)) {
550 if (irqflags & desc->action->flags & IRQF_SHARED)
553 irq_put_desc_unlock(desc, flags);
557 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
560 struct irq_chip *chip = desc->irq_data.chip;
563 if (!chip || !chip->irq_set_type) {
565 * IRQF_TRIGGER_* but the PIC does not support multiple
568 pr_debug("genirq: No set_type function for IRQ %d (%s)\n", irq,
569 chip ? (chip->name ? : "unknown") : "unknown");
573 flags &= IRQ_TYPE_SENSE_MASK;
575 if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
576 if (!irqd_irq_masked(&desc->irq_data))
578 if (!irqd_irq_disabled(&desc->irq_data))
582 /* caller masked out all except trigger mode flags */
583 ret = chip->irq_set_type(&desc->irq_data, flags);
586 case IRQ_SET_MASK_OK:
587 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
588 irqd_set(&desc->irq_data, flags);
590 case IRQ_SET_MASK_OK_NOCOPY:
591 flags = irqd_get_trigger_type(&desc->irq_data);
592 irq_settings_set_trigger_mask(desc, flags);
593 irqd_clear(&desc->irq_data, IRQD_LEVEL);
594 irq_settings_clr_level(desc);
595 if (flags & IRQ_TYPE_LEVEL_MASK) {
596 irq_settings_set_level(desc);
597 irqd_set(&desc->irq_data, IRQD_LEVEL);
603 pr_err("genirq: Setting trigger mode %lu for irq %u failed (%pF)\n",
604 flags, irq, chip->irq_set_type);
612 * Default primary interrupt handler for threaded interrupts. Is
613 * assigned as primary handler when request_threaded_irq is called
614 * with handler == NULL. Useful for oneshot interrupts.
616 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
618 return IRQ_WAKE_THREAD;
622 * Primary handler for nested threaded interrupts. Should never be
625 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
627 WARN(1, "Primary handler called for nested irq %d\n", irq);
631 static int irq_wait_for_interrupt(struct irqaction *action)
633 set_current_state(TASK_INTERRUPTIBLE);
635 while (!kthread_should_stop()) {
637 if (test_and_clear_bit(IRQTF_RUNTHREAD,
638 &action->thread_flags)) {
639 __set_current_state(TASK_RUNNING);
643 set_current_state(TASK_INTERRUPTIBLE);
645 __set_current_state(TASK_RUNNING);
650 * Oneshot interrupts keep the irq line masked until the threaded
651 * handler finished. unmask if the interrupt has not been disabled and
654 static void irq_finalize_oneshot(struct irq_desc *desc,
655 struct irqaction *action)
657 if (!(desc->istate & IRQS_ONESHOT))
661 raw_spin_lock_irq(&desc->lock);
664 * Implausible though it may be we need to protect us against
665 * the following scenario:
667 * The thread is faster done than the hard interrupt handler
668 * on the other CPU. If we unmask the irq line then the
669 * interrupt can come in again and masks the line, leaves due
670 * to IRQS_INPROGRESS and the irq line is masked forever.
672 * This also serializes the state of shared oneshot handlers
673 * versus "desc->threads_onehsot |= action->thread_mask;" in
674 * irq_wake_thread(). See the comment there which explains the
677 if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
678 raw_spin_unlock_irq(&desc->lock);
679 chip_bus_sync_unlock(desc);
685 * Now check again, whether the thread should run. Otherwise
686 * we would clear the threads_oneshot bit of this thread which
689 if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
692 desc->threads_oneshot &= ~action->thread_mask;
694 if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
695 irqd_irq_masked(&desc->irq_data))
699 raw_spin_unlock_irq(&desc->lock);
700 chip_bus_sync_unlock(desc);
705 * Check whether we need to chasnge the affinity of the interrupt thread.
708 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
712 if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
716 * In case we are out of memory we set IRQTF_AFFINITY again and
717 * try again next time
719 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
720 set_bit(IRQTF_AFFINITY, &action->thread_flags);
724 raw_spin_lock_irq(&desc->lock);
725 cpumask_copy(mask, desc->irq_data.affinity);
726 raw_spin_unlock_irq(&desc->lock);
728 set_cpus_allowed_ptr(current, mask);
729 free_cpumask_var(mask);
733 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
737 * Interrupts which are not explicitely requested as threaded
738 * interrupts rely on the implicit bh/preempt disable of the hard irq
739 * context. So we need to disable bh here to avoid deadlocks and other
743 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
748 ret = action->thread_fn(action->irq, action->dev_id);
749 irq_finalize_oneshot(desc, action);
755 * Interrupts explicitely requested as threaded interupts want to be
756 * preemtible - many of them need to sleep and wait for slow busses to
759 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
760 struct irqaction *action)
764 ret = action->thread_fn(action->irq, action->dev_id);
765 irq_finalize_oneshot(desc, action);
769 static void wake_threads_waitq(struct irq_desc *desc)
771 if (atomic_dec_and_test(&desc->threads_active) &&
772 waitqueue_active(&desc->wait_for_threads))
773 wake_up(&desc->wait_for_threads);
777 * Interrupt handler thread
779 static int irq_thread(void *data)
781 static const struct sched_param param = {
782 .sched_priority = MAX_USER_RT_PRIO/2,
784 struct irqaction *action = data;
785 struct irq_desc *desc = irq_to_desc(action->irq);
786 irqreturn_t (*handler_fn)(struct irq_desc *desc,
787 struct irqaction *action);
789 if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
790 &action->thread_flags))
791 handler_fn = irq_forced_thread_fn;
793 handler_fn = irq_thread_fn;
795 sched_setscheduler(current, SCHED_FIFO, ¶m);
796 current->irq_thread = 1;
798 while (!irq_wait_for_interrupt(action)) {
799 irqreturn_t action_ret;
801 irq_thread_check_affinity(desc, action);
803 action_ret = handler_fn(desc, action);
805 note_interrupt(action->irq, desc, action_ret);
807 wake_threads_waitq(desc);
811 * This is the regular exit path. __free_irq() is stopping the
812 * thread via kthread_stop() after calling
813 * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
814 * oneshot mask bit can be set. We cannot verify that as we
815 * cannot touch the oneshot mask at this point anymore as
816 * __setup_irq() might have given out currents thread_mask
819 * Clear irq_thread. Otherwise exit_irq_thread() would make
820 * fuzz about an active irq thread going into nirvana.
822 current->irq_thread = 0;
827 * Called from do_exit()
829 void exit_irq_thread(void)
831 struct task_struct *tsk = current;
832 struct irq_desc *desc;
833 struct irqaction *action;
835 if (!tsk->irq_thread)
838 action = kthread_data(tsk);
840 pr_err("genirq: exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
841 tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
843 desc = irq_to_desc(action->irq);
846 * If IRQTF_RUNTHREAD is set, we need to decrement
847 * desc->threads_active and wake possible waiters.
849 if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
850 wake_threads_waitq(desc);
852 /* Prevent a stale desc->threads_oneshot */
853 irq_finalize_oneshot(desc, action);
856 static void irq_setup_forced_threading(struct irqaction *new)
858 if (!force_irqthreads)
860 if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
863 new->flags |= IRQF_ONESHOT;
865 if (!new->thread_fn) {
866 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
867 new->thread_fn = new->handler;
868 new->handler = irq_default_primary_handler;
873 * Internal function to register an irqaction - typically used to
874 * allocate special interrupts that are part of the architecture.
877 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
879 struct irqaction *old, **old_ptr;
880 unsigned long flags, thread_mask = 0;
881 int ret, nested, shared = 0;
887 if (desc->irq_data.chip == &no_irq_chip)
889 if (!try_module_get(desc->owner))
892 * Some drivers like serial.c use request_irq() heavily,
893 * so we have to be careful not to interfere with a
896 if (new->flags & IRQF_SAMPLE_RANDOM) {
898 * This function might sleep, we want to call it first,
899 * outside of the atomic block.
900 * Yes, this might clear the entropy pool if the wrong
901 * driver is attempted to be loaded, without actually
902 * installing a new handler, but is this really a problem,
903 * only the sysadmin is able to do this.
905 rand_initialize_irq(irq);
909 * Check whether the interrupt nests into another interrupt
912 nested = irq_settings_is_nested_thread(desc);
914 if (!new->thread_fn) {
919 * Replace the primary handler which was provided from
920 * the driver for non nested interrupt handling by the
921 * dummy function which warns when called.
923 new->handler = irq_nested_primary_handler;
925 if (irq_settings_can_thread(desc))
926 irq_setup_forced_threading(new);
930 * Create a handler thread when a thread function is supplied
931 * and the interrupt does not nest into another interrupt
934 if (new->thread_fn && !nested) {
935 struct task_struct *t;
937 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
944 * We keep the reference to the task struct even if
945 * the thread dies to avoid that the interrupt code
946 * references an already freed task_struct.
952 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
958 * The following block of code has to be executed atomically
960 raw_spin_lock_irqsave(&desc->lock, flags);
961 old_ptr = &desc->action;
965 * Can't share interrupts unless both agree to and are
966 * the same type (level, edge, polarity). So both flag
967 * fields must have IRQF_SHARED set and the bits which
968 * set the trigger type must match. Also all must
971 if (!((old->flags & new->flags) & IRQF_SHARED) ||
972 ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
973 ((old->flags ^ new->flags) & IRQF_ONESHOT))
976 /* All handlers must agree on per-cpuness */
977 if ((old->flags & IRQF_PERCPU) !=
978 (new->flags & IRQF_PERCPU))
981 /* add new interrupt at end of irq queue */
984 * Or all existing action->thread_mask bits,
985 * so we can find the next zero bit for this
988 thread_mask |= old->thread_mask;
989 old_ptr = &old->next;
996 * Setup the thread mask for this irqaction for ONESHOT. For
997 * !ONESHOT irqs the thread mask is 0 so we can avoid a
998 * conditional in irq_wake_thread().
1000 if (new->flags & IRQF_ONESHOT) {
1002 * Unlikely to have 32 resp 64 irqs sharing one line,
1005 if (thread_mask == ~0UL) {
1010 * The thread_mask for the action is or'ed to
1011 * desc->thread_active to indicate that the
1012 * IRQF_ONESHOT thread handler has been woken, but not
1013 * yet finished. The bit is cleared when a thread
1014 * completes. When all threads of a shared interrupt
1015 * line have completed desc->threads_active becomes
1016 * zero and the interrupt line is unmasked. See
1017 * handle.c:irq_wake_thread() for further information.
1019 * If no thread is woken by primary (hard irq context)
1020 * interrupt handlers, then desc->threads_active is
1021 * also checked for zero to unmask the irq line in the
1022 * affected hard irq flow handlers
1023 * (handle_[fasteoi|level]_irq).
1025 * The new action gets the first zero bit of
1026 * thread_mask assigned. See the loop above which or's
1027 * all existing action->thread_mask bits.
1029 new->thread_mask = 1 << ffz(thread_mask);
1031 } else if (new->handler == irq_default_primary_handler) {
1033 * The interrupt was requested with handler = NULL, so
1034 * we use the default primary handler for it. But it
1035 * does not have the oneshot flag set. In combination
1036 * with level interrupts this is deadly, because the
1037 * default primary handler just wakes the thread, then
1038 * the irq lines is reenabled, but the device still
1039 * has the level irq asserted. Rinse and repeat....
1041 * While this works for edge type interrupts, we play
1042 * it safe and reject unconditionally because we can't
1043 * say for sure which type this interrupt really
1044 * has. The type flags are unreliable as the
1045 * underlying chip implementation can override them.
1047 pr_err("genirq: Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1054 init_waitqueue_head(&desc->wait_for_threads);
1056 /* Setup the type (level, edge polarity) if configured: */
1057 if (new->flags & IRQF_TRIGGER_MASK) {
1058 ret = __irq_set_trigger(desc, irq,
1059 new->flags & IRQF_TRIGGER_MASK);
1065 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1066 IRQS_ONESHOT | IRQS_WAITING);
1067 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1069 if (new->flags & IRQF_PERCPU) {
1070 irqd_set(&desc->irq_data, IRQD_PER_CPU);
1071 irq_settings_set_per_cpu(desc);
1074 if (new->flags & IRQF_ONESHOT)
1075 desc->istate |= IRQS_ONESHOT;
1077 if (irq_settings_can_autoenable(desc))
1078 irq_startup(desc, true);
1080 /* Undo nested disables: */
1083 /* Exclude IRQ from balancing if requested */
1084 if (new->flags & IRQF_NOBALANCING) {
1085 irq_settings_set_no_balancing(desc);
1086 irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1089 /* Set default affinity mask once everything is setup */
1090 setup_affinity(irq, desc, mask);
1092 } else if (new->flags & IRQF_TRIGGER_MASK) {
1093 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1094 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1097 /* hope the handler works with current trigger mode */
1098 pr_warning("genirq: irq %d uses trigger mode %u; requested %u\n",
1105 /* Reset broken irq detection when installing new handler */
1106 desc->irq_count = 0;
1107 desc->irqs_unhandled = 0;
1110 * Check whether we disabled the irq via the spurious handler
1111 * before. Reenable it and give it another chance.
1113 if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1114 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1115 __enable_irq(desc, irq, false);
1118 raw_spin_unlock_irqrestore(&desc->lock, flags);
1121 * Strictly no need to wake it up, but hung_task complains
1122 * when no hard interrupt wakes the thread up.
1125 wake_up_process(new->thread);
1127 register_irq_proc(irq, desc);
1129 register_handler_proc(irq, new);
1130 free_cpumask_var(mask);
1135 if (!(new->flags & IRQF_PROBE_SHARED)) {
1136 pr_err("genirq: Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1137 irq, new->flags, new->name, old->flags, old->name);
1138 #ifdef CONFIG_DEBUG_SHIRQ
1145 raw_spin_unlock_irqrestore(&desc->lock, flags);
1146 free_cpumask_var(mask);
1150 struct task_struct *t = new->thread;
1157 module_put(desc->owner);
1162 * setup_irq - setup an interrupt
1163 * @irq: Interrupt line to setup
1164 * @act: irqaction for the interrupt
1166 * Used to statically setup interrupts in the early boot process.
1168 int setup_irq(unsigned int irq, struct irqaction *act)
1171 struct irq_desc *desc = irq_to_desc(irq);
1173 if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1175 chip_bus_lock(desc);
1176 retval = __setup_irq(irq, desc, act);
1177 chip_bus_sync_unlock(desc);
1181 EXPORT_SYMBOL_GPL(setup_irq);
1184 * Internal function to unregister an irqaction - used to free
1185 * regular and special interrupts that are part of the architecture.
1187 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1189 struct irq_desc *desc = irq_to_desc(irq);
1190 struct irqaction *action, **action_ptr;
1191 unsigned long flags;
1193 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1198 raw_spin_lock_irqsave(&desc->lock, flags);
1201 * There can be multiple actions per IRQ descriptor, find the right
1202 * one based on the dev_id:
1204 action_ptr = &desc->action;
1206 action = *action_ptr;
1209 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1210 raw_spin_unlock_irqrestore(&desc->lock, flags);
1215 if (action->dev_id == dev_id)
1217 action_ptr = &action->next;
1220 /* Found it - now remove it from the list of entries: */
1221 *action_ptr = action->next;
1223 /* Currently used only by UML, might disappear one day: */
1224 #ifdef CONFIG_IRQ_RELEASE_METHOD
1225 if (desc->irq_data.chip->release)
1226 desc->irq_data.chip->release(irq, dev_id);
1229 /* If this was the last handler, shut down the IRQ line: */
1234 /* make sure affinity_hint is cleaned up */
1235 if (WARN_ON_ONCE(desc->affinity_hint))
1236 desc->affinity_hint = NULL;
1239 raw_spin_unlock_irqrestore(&desc->lock, flags);
1241 unregister_handler_proc(irq, action);
1243 /* Make sure it's not being used on another CPU: */
1244 synchronize_irq(irq);
1246 #ifdef CONFIG_DEBUG_SHIRQ
1248 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1249 * event to happen even now it's being freed, so let's make sure that
1250 * is so by doing an extra call to the handler ....
1252 * ( We do this after actually deregistering it, to make sure that a
1253 * 'real' IRQ doesn't run in * parallel with our fake. )
1255 if (action->flags & IRQF_SHARED) {
1256 local_irq_save(flags);
1257 action->handler(irq, dev_id);
1258 local_irq_restore(flags);
1262 if (action->thread) {
1263 kthread_stop(action->thread);
1264 put_task_struct(action->thread);
1267 module_put(desc->owner);
1272 * remove_irq - free an interrupt
1273 * @irq: Interrupt line to free
1274 * @act: irqaction for the interrupt
1276 * Used to remove interrupts statically setup by the early boot process.
1278 void remove_irq(unsigned int irq, struct irqaction *act)
1280 struct irq_desc *desc = irq_to_desc(irq);
1282 if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1283 __free_irq(irq, act->dev_id);
1285 EXPORT_SYMBOL_GPL(remove_irq);
1288 * free_irq - free an interrupt allocated with request_irq
1289 * @irq: Interrupt line to free
1290 * @dev_id: Device identity to free
1292 * Remove an interrupt handler. The handler is removed and if the
1293 * interrupt line is no longer in use by any driver it is disabled.
1294 * On a shared IRQ the caller must ensure the interrupt is disabled
1295 * on the card it drives before calling this function. The function
1296 * does not return until any executing interrupts for this IRQ
1299 * This function must not be called from interrupt context.
1301 void free_irq(unsigned int irq, void *dev_id)
1303 struct irq_desc *desc = irq_to_desc(irq);
1305 if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1309 if (WARN_ON(desc->affinity_notify))
1310 desc->affinity_notify = NULL;
1313 chip_bus_lock(desc);
1314 kfree(__free_irq(irq, dev_id));
1315 chip_bus_sync_unlock(desc);
1317 EXPORT_SYMBOL(free_irq);
1320 * request_threaded_irq - allocate an interrupt line
1321 * @irq: Interrupt line to allocate
1322 * @handler: Function to be called when the IRQ occurs.
1323 * Primary handler for threaded interrupts
1324 * If NULL and thread_fn != NULL the default
1325 * primary handler is installed
1326 * @thread_fn: Function called from the irq handler thread
1327 * If NULL, no irq thread is created
1328 * @irqflags: Interrupt type flags
1329 * @devname: An ascii name for the claiming device
1330 * @dev_id: A cookie passed back to the handler function
1332 * This call allocates interrupt resources and enables the
1333 * interrupt line and IRQ handling. From the point this
1334 * call is made your handler function may be invoked. Since
1335 * your handler function must clear any interrupt the board
1336 * raises, you must take care both to initialise your hardware
1337 * and to set up the interrupt handler in the right order.
1339 * If you want to set up a threaded irq handler for your device
1340 * then you need to supply @handler and @thread_fn. @handler is
1341 * still called in hard interrupt context and has to check
1342 * whether the interrupt originates from the device. If yes it
1343 * needs to disable the interrupt on the device and return
1344 * IRQ_WAKE_THREAD which will wake up the handler thread and run
1345 * @thread_fn. This split handler design is necessary to support
1346 * shared interrupts.
1348 * Dev_id must be globally unique. Normally the address of the
1349 * device data structure is used as the cookie. Since the handler
1350 * receives this value it makes sense to use it.
1352 * If your interrupt is shared you must pass a non NULL dev_id
1353 * as this is required when freeing the interrupt.
1357 * IRQF_SHARED Interrupt is shared
1358 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
1359 * IRQF_TRIGGER_* Specify active edge(s) or level
1362 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1363 irq_handler_t thread_fn, unsigned long irqflags,
1364 const char *devname, void *dev_id)
1366 struct irqaction *action;
1367 struct irq_desc *desc;
1371 * Sanity-check: shared interrupts must pass in a real dev-ID,
1372 * otherwise we'll have trouble later trying to figure out
1373 * which interrupt is which (messes up the interrupt freeing
1376 if ((irqflags & IRQF_SHARED) && !dev_id)
1379 desc = irq_to_desc(irq);
1383 if (!irq_settings_can_request(desc) ||
1384 WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1390 handler = irq_default_primary_handler;
1393 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1397 action->handler = handler;
1398 action->thread_fn = thread_fn;
1399 action->flags = irqflags;
1400 action->name = devname;
1401 action->dev_id = dev_id;
1403 chip_bus_lock(desc);
1404 retval = __setup_irq(irq, desc, action);
1405 chip_bus_sync_unlock(desc);
1410 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1411 if (!retval && (irqflags & IRQF_SHARED)) {
1413 * It's a shared IRQ -- the driver ought to be prepared for it
1414 * to happen immediately, so let's make sure....
1415 * We disable the irq to make sure that a 'real' IRQ doesn't
1416 * run in parallel with our fake.
1418 unsigned long flags;
1421 local_irq_save(flags);
1423 handler(irq, dev_id);
1425 local_irq_restore(flags);
1431 EXPORT_SYMBOL(request_threaded_irq);
1434 * request_any_context_irq - allocate an interrupt line
1435 * @irq: Interrupt line to allocate
1436 * @handler: Function to be called when the IRQ occurs.
1437 * Threaded handler for threaded interrupts.
1438 * @flags: Interrupt type flags
1439 * @name: An ascii name for the claiming device
1440 * @dev_id: A cookie passed back to the handler function
1442 * This call allocates interrupt resources and enables the
1443 * interrupt line and IRQ handling. It selects either a
1444 * hardirq or threaded handling method depending on the
1447 * On failure, it returns a negative value. On success,
1448 * it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1450 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1451 unsigned long flags, const char *name, void *dev_id)
1453 struct irq_desc *desc = irq_to_desc(irq);
1459 if (irq_settings_is_nested_thread(desc)) {
1460 ret = request_threaded_irq(irq, NULL, handler,
1461 flags, name, dev_id);
1462 return !ret ? IRQC_IS_NESTED : ret;
1465 ret = request_irq(irq, handler, flags, name, dev_id);
1466 return !ret ? IRQC_IS_HARDIRQ : ret;
1468 EXPORT_SYMBOL_GPL(request_any_context_irq);
1470 void enable_percpu_irq(unsigned int irq, unsigned int type)
1472 unsigned int cpu = smp_processor_id();
1473 unsigned long flags;
1474 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1479 type &= IRQ_TYPE_SENSE_MASK;
1480 if (type != IRQ_TYPE_NONE) {
1483 ret = __irq_set_trigger(desc, irq, type);
1486 WARN(1, "failed to set type for IRQ%d\n", irq);
1491 irq_percpu_enable(desc, cpu);
1493 irq_put_desc_unlock(desc, flags);
1496 void disable_percpu_irq(unsigned int irq)
1498 unsigned int cpu = smp_processor_id();
1499 unsigned long flags;
1500 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1505 irq_percpu_disable(desc, cpu);
1506 irq_put_desc_unlock(desc, flags);
1510 * Internal function to unregister a percpu irqaction.
1512 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1514 struct irq_desc *desc = irq_to_desc(irq);
1515 struct irqaction *action;
1516 unsigned long flags;
1518 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1523 raw_spin_lock_irqsave(&desc->lock, flags);
1525 action = desc->action;
1526 if (!action || action->percpu_dev_id != dev_id) {
1527 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1531 if (!cpumask_empty(desc->percpu_enabled)) {
1532 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1533 irq, cpumask_first(desc->percpu_enabled));
1537 /* Found it - now remove it from the list of entries: */
1538 desc->action = NULL;
1540 raw_spin_unlock_irqrestore(&desc->lock, flags);
1542 unregister_handler_proc(irq, action);
1544 module_put(desc->owner);
1548 raw_spin_unlock_irqrestore(&desc->lock, flags);
1553 * remove_percpu_irq - free a per-cpu interrupt
1554 * @irq: Interrupt line to free
1555 * @act: irqaction for the interrupt
1557 * Used to remove interrupts statically setup by the early boot process.
1559 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1561 struct irq_desc *desc = irq_to_desc(irq);
1563 if (desc && irq_settings_is_per_cpu_devid(desc))
1564 __free_percpu_irq(irq, act->percpu_dev_id);
1568 * free_percpu_irq - free an interrupt allocated with request_percpu_irq
1569 * @irq: Interrupt line to free
1570 * @dev_id: Device identity to free
1572 * Remove a percpu interrupt handler. The handler is removed, but
1573 * the interrupt line is not disabled. This must be done on each
1574 * CPU before calling this function. The function does not return
1575 * until any executing interrupts for this IRQ have completed.
1577 * This function must not be called from interrupt context.
1579 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1581 struct irq_desc *desc = irq_to_desc(irq);
1583 if (!desc || !irq_settings_is_per_cpu_devid(desc))
1586 chip_bus_lock(desc);
1587 kfree(__free_percpu_irq(irq, dev_id));
1588 chip_bus_sync_unlock(desc);
1592 * setup_percpu_irq - setup a per-cpu interrupt
1593 * @irq: Interrupt line to setup
1594 * @act: irqaction for the interrupt
1596 * Used to statically setup per-cpu interrupts in the early boot process.
1598 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1600 struct irq_desc *desc = irq_to_desc(irq);
1603 if (!desc || !irq_settings_is_per_cpu_devid(desc))
1605 chip_bus_lock(desc);
1606 retval = __setup_irq(irq, desc, act);
1607 chip_bus_sync_unlock(desc);
1613 * request_percpu_irq - allocate a percpu interrupt line
1614 * @irq: Interrupt line to allocate
1615 * @handler: Function to be called when the IRQ occurs.
1616 * @devname: An ascii name for the claiming device
1617 * @dev_id: A percpu cookie passed back to the handler function
1619 * This call allocates interrupt resources, but doesn't
1620 * automatically enable the interrupt. It has to be done on each
1621 * CPU using enable_percpu_irq().
1623 * Dev_id must be globally unique. It is a per-cpu variable, and
1624 * the handler gets called with the interrupted CPU's instance of
1627 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1628 const char *devname, void __percpu *dev_id)
1630 struct irqaction *action;
1631 struct irq_desc *desc;
1637 desc = irq_to_desc(irq);
1638 if (!desc || !irq_settings_can_request(desc) ||
1639 !irq_settings_is_per_cpu_devid(desc))
1642 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1646 action->handler = handler;
1647 action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1648 action->name = devname;
1649 action->percpu_dev_id = dev_id;
1651 chip_bus_lock(desc);
1652 retval = __setup_irq(irq, desc, action);
1653 chip_bus_sync_unlock(desc);