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 #define pr_fmt(fmt) "genirq: " fmt
12 #include <linux/irq.h>
13 #include <linux/kthread.h>
14 #include <linux/module.h>
15 #include <linux/random.h>
16 #include <linux/interrupt.h>
17 #include <linux/slab.h>
18 #include <linux/sched.h>
19 #include <linux/sched/rt.h>
20 #include <linux/task_work.h>
22 #include "internals.h"
24 #ifdef CONFIG_IRQ_FORCED_THREADING
25 __read_mostly bool force_irqthreads;
27 static int __init setup_forced_irqthreads(char *arg)
29 force_irqthreads = true;
32 early_param("threadirqs", setup_forced_irqthreads);
36 * synchronize_irq - wait for pending IRQ handlers (on other CPUs)
37 * @irq: interrupt number to wait for
39 * This function waits for any pending IRQ handlers for this interrupt
40 * to complete before returning. If you use this function while
41 * holding a resource the IRQ handler may need you will deadlock.
43 * This function may be called - with care - from IRQ context.
45 void synchronize_irq(unsigned int irq)
47 struct irq_desc *desc = irq_to_desc(irq);
57 * Wait until we're out of the critical section. This might
58 * give the wrong answer due to the lack of memory barriers.
60 while (irqd_irq_inprogress(&desc->irq_data))
63 /* Ok, that indicated we're done: double-check carefully. */
64 raw_spin_lock_irqsave(&desc->lock, flags);
65 inprogress = irqd_irq_inprogress(&desc->irq_data);
66 raw_spin_unlock_irqrestore(&desc->lock, flags);
68 /* Oops, that failed? */
72 * We made sure that no hardirq handler is running. Now verify
73 * that no threaded handlers are active.
75 wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
77 EXPORT_SYMBOL(synchronize_irq);
80 cpumask_var_t irq_default_affinity;
83 * irq_can_set_affinity - Check if the affinity of a given irq can be set
84 * @irq: Interrupt to check
87 int irq_can_set_affinity(unsigned int irq)
89 struct irq_desc *desc = irq_to_desc(irq);
91 if (!desc || !irqd_can_balance(&desc->irq_data) ||
92 !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
99 * irq_set_thread_affinity - Notify irq threads to adjust affinity
100 * @desc: irq descriptor which has affitnity changed
102 * We just set IRQTF_AFFINITY and delegate the affinity setting
103 * to the interrupt thread itself. We can not call
104 * set_cpus_allowed_ptr() here as we hold desc->lock and this
105 * code can be called from hard interrupt context.
107 void irq_set_thread_affinity(struct irq_desc *desc)
109 struct irqaction *action = desc->action;
113 set_bit(IRQTF_AFFINITY, &action->thread_flags);
114 action = action->next;
118 #ifdef CONFIG_GENERIC_PENDING_IRQ
119 static inline bool irq_can_move_pcntxt(struct irq_data *data)
121 return irqd_can_move_in_process_context(data);
123 static inline bool irq_move_pending(struct irq_data *data)
125 return irqd_is_setaffinity_pending(data);
128 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
130 cpumask_copy(desc->pending_mask, mask);
133 irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
135 cpumask_copy(mask, desc->pending_mask);
138 static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
139 static inline bool irq_move_pending(struct irq_data *data) { return false; }
141 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
143 irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
146 int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
149 struct irq_desc *desc = irq_data_to_desc(data);
150 struct irq_chip *chip = irq_data_get_irq_chip(data);
153 ret = chip->irq_set_affinity(data, mask, force);
155 case IRQ_SET_MASK_OK:
156 cpumask_copy(data->affinity, mask);
157 case IRQ_SET_MASK_OK_NOCOPY:
158 irq_set_thread_affinity(desc);
165 int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
168 struct irq_chip *chip = irq_data_get_irq_chip(data);
169 struct irq_desc *desc = irq_data_to_desc(data);
172 if (!chip || !chip->irq_set_affinity)
175 if (irq_can_move_pcntxt(data)) {
176 ret = irq_do_set_affinity(data, mask, force);
178 irqd_set_move_pending(data);
179 irq_copy_pending(desc, mask);
182 if (desc->affinity_notify) {
183 kref_get(&desc->affinity_notify->kref);
184 schedule_work(&desc->affinity_notify->work);
186 irqd_set(data, IRQD_AFFINITY_SET);
191 int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
193 struct irq_desc *desc = irq_to_desc(irq);
200 raw_spin_lock_irqsave(&desc->lock, flags);
201 ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force);
202 raw_spin_unlock_irqrestore(&desc->lock, flags);
206 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
209 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
213 desc->affinity_hint = m;
214 irq_put_desc_unlock(desc, flags);
217 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
219 static void irq_affinity_notify(struct work_struct *work)
221 struct irq_affinity_notify *notify =
222 container_of(work, struct irq_affinity_notify, work);
223 struct irq_desc *desc = irq_to_desc(notify->irq);
224 cpumask_var_t cpumask;
227 if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
230 raw_spin_lock_irqsave(&desc->lock, flags);
231 if (irq_move_pending(&desc->irq_data))
232 irq_get_pending(cpumask, desc);
234 cpumask_copy(cpumask, desc->irq_data.affinity);
235 raw_spin_unlock_irqrestore(&desc->lock, flags);
237 notify->notify(notify, cpumask);
239 free_cpumask_var(cpumask);
241 kref_put(¬ify->kref, notify->release);
245 * irq_set_affinity_notifier - control notification of IRQ affinity changes
246 * @irq: Interrupt for which to enable/disable notification
247 * @notify: Context for notification, or %NULL to disable
248 * notification. Function pointers must be initialised;
249 * the other fields will be initialised by this function.
251 * Must be called in process context. Notification may only be enabled
252 * after the IRQ is allocated and must be disabled before the IRQ is
253 * freed using free_irq().
256 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
258 struct irq_desc *desc = irq_to_desc(irq);
259 struct irq_affinity_notify *old_notify;
262 /* The release function is promised process context */
268 /* Complete initialisation of *notify */
271 kref_init(¬ify->kref);
272 INIT_WORK(¬ify->work, irq_affinity_notify);
275 raw_spin_lock_irqsave(&desc->lock, flags);
276 old_notify = desc->affinity_notify;
277 desc->affinity_notify = notify;
278 raw_spin_unlock_irqrestore(&desc->lock, flags);
281 kref_put(&old_notify->kref, old_notify->release);
285 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
287 #ifndef CONFIG_AUTO_IRQ_AFFINITY
289 * Generic version of the affinity autoselector.
292 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
294 struct cpumask *set = irq_default_affinity;
295 int node = desc->irq_data.node;
297 /* Excludes PER_CPU and NO_BALANCE interrupts */
298 if (!irq_can_set_affinity(irq))
302 * Preserve an userspace affinity setup, but make sure that
303 * one of the targets is online.
305 if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
306 if (cpumask_intersects(desc->irq_data.affinity,
308 set = desc->irq_data.affinity;
310 irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
313 cpumask_and(mask, cpu_online_mask, set);
314 if (node != NUMA_NO_NODE) {
315 const struct cpumask *nodemask = cpumask_of_node(node);
317 /* make sure at least one of the cpus in nodemask is online */
318 if (cpumask_intersects(mask, nodemask))
319 cpumask_and(mask, mask, nodemask);
321 irq_do_set_affinity(&desc->irq_data, mask, false);
326 setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
328 return irq_select_affinity(irq);
333 * Called when affinity is set via /proc/irq
335 int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
337 struct irq_desc *desc = irq_to_desc(irq);
341 raw_spin_lock_irqsave(&desc->lock, flags);
342 ret = setup_affinity(irq, desc, mask);
343 raw_spin_unlock_irqrestore(&desc->lock, flags);
349 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
355 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
358 if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
360 desc->istate |= IRQS_SUSPENDED;
367 static int __disable_irq_nosync(unsigned int irq)
370 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
374 __disable_irq(desc, irq, false);
375 irq_put_desc_busunlock(desc, flags);
380 * disable_irq_nosync - disable an irq without waiting
381 * @irq: Interrupt to disable
383 * Disable the selected interrupt line. Disables and Enables are
385 * Unlike disable_irq(), this function does not ensure existing
386 * instances of the IRQ handler have completed before returning.
388 * This function may be called from IRQ context.
390 void disable_irq_nosync(unsigned int irq)
392 __disable_irq_nosync(irq);
394 EXPORT_SYMBOL(disable_irq_nosync);
397 * disable_irq - disable an irq and wait for completion
398 * @irq: Interrupt to disable
400 * Disable the selected interrupt line. Enables and Disables are
402 * This function waits for any pending IRQ handlers for this interrupt
403 * to complete before returning. If you use this function while
404 * holding a resource the IRQ handler may need you will deadlock.
406 * This function may be called - with care - from IRQ context.
408 void disable_irq(unsigned int irq)
410 if (!__disable_irq_nosync(irq))
411 synchronize_irq(irq);
413 EXPORT_SYMBOL(disable_irq);
415 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
418 if (!(desc->istate & IRQS_SUSPENDED)) {
421 if (!(desc->action->flags & IRQF_FORCE_RESUME))
423 /* Pretend that it got disabled ! */
426 desc->istate &= ~IRQS_SUSPENDED;
429 switch (desc->depth) {
432 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
435 if (desc->istate & IRQS_SUSPENDED)
437 /* Prevent probing on this irq: */
438 irq_settings_set_noprobe(desc);
440 check_irq_resend(desc, irq);
449 * enable_irq - enable handling of an irq
450 * @irq: Interrupt to enable
452 * Undoes the effect of one call to disable_irq(). If this
453 * matches the last disable, processing of interrupts on this
454 * IRQ line is re-enabled.
456 * This function may be called from IRQ context only when
457 * desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
459 void enable_irq(unsigned int irq)
462 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
466 if (WARN(!desc->irq_data.chip,
467 KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
470 __enable_irq(desc, irq, false);
472 irq_put_desc_busunlock(desc, flags);
474 EXPORT_SYMBOL(enable_irq);
476 static int set_irq_wake_real(unsigned int irq, unsigned int on)
478 struct irq_desc *desc = irq_to_desc(irq);
481 if (irq_desc_get_chip(desc)->flags & IRQCHIP_SKIP_SET_WAKE)
484 if (desc->irq_data.chip->irq_set_wake)
485 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
491 * irq_set_irq_wake - control irq power management wakeup
492 * @irq: interrupt to control
493 * @on: enable/disable power management wakeup
495 * Enable/disable power management wakeup mode, which is
496 * disabled by default. Enables and disables must match,
497 * just as they match for non-wakeup mode support.
499 * Wakeup mode lets this IRQ wake the system from sleep
500 * states like "suspend to RAM".
502 int irq_set_irq_wake(unsigned int irq, unsigned int on)
505 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
511 /* wakeup-capable irqs can be shared between drivers that
512 * don't need to have the same sleep mode behaviors.
515 if (desc->wake_depth++ == 0) {
516 ret = set_irq_wake_real(irq, on);
518 desc->wake_depth = 0;
520 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
523 if (desc->wake_depth == 0) {
524 WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
525 } else if (--desc->wake_depth == 0) {
526 ret = set_irq_wake_real(irq, on);
528 desc->wake_depth = 1;
530 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
533 irq_put_desc_busunlock(desc, flags);
536 EXPORT_SYMBOL(irq_set_irq_wake);
539 * Internal function that tells the architecture code whether a
540 * particular irq has been exclusively allocated or is available
543 int can_request_irq(unsigned int irq, unsigned long irqflags)
546 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
552 if (irq_settings_can_request(desc)) {
554 irqflags & desc->action->flags & IRQF_SHARED)
557 irq_put_desc_unlock(desc, flags);
561 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
564 struct irq_chip *chip = desc->irq_data.chip;
567 if (!chip || !chip->irq_set_type) {
569 * IRQF_TRIGGER_* but the PIC does not support multiple
572 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
573 chip ? (chip->name ? : "unknown") : "unknown");
577 flags &= IRQ_TYPE_SENSE_MASK;
579 if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
580 if (!irqd_irq_masked(&desc->irq_data))
582 if (!irqd_irq_disabled(&desc->irq_data))
586 /* caller masked out all except trigger mode flags */
587 ret = chip->irq_set_type(&desc->irq_data, flags);
590 case IRQ_SET_MASK_OK:
591 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
592 irqd_set(&desc->irq_data, flags);
594 case IRQ_SET_MASK_OK_NOCOPY:
595 flags = irqd_get_trigger_type(&desc->irq_data);
596 irq_settings_set_trigger_mask(desc, flags);
597 irqd_clear(&desc->irq_data, IRQD_LEVEL);
598 irq_settings_clr_level(desc);
599 if (flags & IRQ_TYPE_LEVEL_MASK) {
600 irq_settings_set_level(desc);
601 irqd_set(&desc->irq_data, IRQD_LEVEL);
607 pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
608 flags, irq, chip->irq_set_type);
615 #ifdef CONFIG_HARDIRQS_SW_RESEND
616 int irq_set_parent(int irq, int parent_irq)
619 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
624 desc->parent_irq = parent_irq;
626 irq_put_desc_unlock(desc, flags);
632 * Default primary interrupt handler for threaded interrupts. Is
633 * assigned as primary handler when request_threaded_irq is called
634 * with handler == NULL. Useful for oneshot interrupts.
636 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
638 return IRQ_WAKE_THREAD;
642 * Primary handler for nested threaded interrupts. Should never be
645 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
647 WARN(1, "Primary handler called for nested irq %d\n", irq);
651 static int irq_wait_for_interrupt(struct irqaction *action)
653 set_current_state(TASK_INTERRUPTIBLE);
655 while (!kthread_should_stop()) {
657 if (test_and_clear_bit(IRQTF_RUNTHREAD,
658 &action->thread_flags)) {
659 __set_current_state(TASK_RUNNING);
663 set_current_state(TASK_INTERRUPTIBLE);
665 __set_current_state(TASK_RUNNING);
670 * Oneshot interrupts keep the irq line masked until the threaded
671 * handler finished. unmask if the interrupt has not been disabled and
674 static void irq_finalize_oneshot(struct irq_desc *desc,
675 struct irqaction *action)
677 if (!(desc->istate & IRQS_ONESHOT))
681 raw_spin_lock_irq(&desc->lock);
684 * Implausible though it may be we need to protect us against
685 * the following scenario:
687 * The thread is faster done than the hard interrupt handler
688 * on the other CPU. If we unmask the irq line then the
689 * interrupt can come in again and masks the line, leaves due
690 * to IRQS_INPROGRESS and the irq line is masked forever.
692 * This also serializes the state of shared oneshot handlers
693 * versus "desc->threads_onehsot |= action->thread_mask;" in
694 * irq_wake_thread(). See the comment there which explains the
697 if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
698 raw_spin_unlock_irq(&desc->lock);
699 chip_bus_sync_unlock(desc);
705 * Now check again, whether the thread should run. Otherwise
706 * we would clear the threads_oneshot bit of this thread which
709 if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
712 desc->threads_oneshot &= ~action->thread_mask;
714 if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
715 irqd_irq_masked(&desc->irq_data))
719 raw_spin_unlock_irq(&desc->lock);
720 chip_bus_sync_unlock(desc);
725 * Check whether we need to chasnge the affinity of the interrupt thread.
728 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
733 if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
737 * In case we are out of memory we set IRQTF_AFFINITY again and
738 * try again next time
740 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
741 set_bit(IRQTF_AFFINITY, &action->thread_flags);
745 raw_spin_lock_irq(&desc->lock);
747 * This code is triggered unconditionally. Check the affinity
748 * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
750 if (desc->irq_data.affinity)
751 cpumask_copy(mask, desc->irq_data.affinity);
754 raw_spin_unlock_irq(&desc->lock);
757 set_cpus_allowed_ptr(current, mask);
758 free_cpumask_var(mask);
762 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
766 * Interrupts which are not explicitely requested as threaded
767 * interrupts rely on the implicit bh/preempt disable of the hard irq
768 * context. So we need to disable bh here to avoid deadlocks and other
772 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
777 ret = action->thread_fn(action->irq, action->dev_id);
778 irq_finalize_oneshot(desc, action);
784 * Interrupts explicitely requested as threaded interupts want to be
785 * preemtible - many of them need to sleep and wait for slow busses to
788 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
789 struct irqaction *action)
793 ret = action->thread_fn(action->irq, action->dev_id);
794 irq_finalize_oneshot(desc, action);
798 static void wake_threads_waitq(struct irq_desc *desc)
800 if (atomic_dec_and_test(&desc->threads_active))
801 wake_up(&desc->wait_for_threads);
804 static void irq_thread_dtor(struct callback_head *unused)
806 struct task_struct *tsk = current;
807 struct irq_desc *desc;
808 struct irqaction *action;
810 if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
813 action = kthread_data(tsk);
815 pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
816 tsk->comm, tsk->pid, action->irq);
819 desc = irq_to_desc(action->irq);
821 * If IRQTF_RUNTHREAD is set, we need to decrement
822 * desc->threads_active and wake possible waiters.
824 if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
825 wake_threads_waitq(desc);
827 /* Prevent a stale desc->threads_oneshot */
828 irq_finalize_oneshot(desc, action);
832 * Interrupt handler thread
834 static int irq_thread(void *data)
836 struct callback_head on_exit_work;
837 static const struct sched_param param = {
838 .sched_priority = MAX_USER_RT_PRIO/2,
840 struct irqaction *action = data;
841 struct irq_desc *desc = irq_to_desc(action->irq);
842 irqreturn_t (*handler_fn)(struct irq_desc *desc,
843 struct irqaction *action);
845 if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
846 &action->thread_flags))
847 handler_fn = irq_forced_thread_fn;
849 handler_fn = irq_thread_fn;
851 sched_setscheduler(current, SCHED_FIFO, ¶m);
853 init_task_work(&on_exit_work, irq_thread_dtor);
854 task_work_add(current, &on_exit_work, false);
856 irq_thread_check_affinity(desc, action);
858 while (!irq_wait_for_interrupt(action)) {
859 irqreturn_t action_ret;
861 irq_thread_check_affinity(desc, action);
863 action_ret = handler_fn(desc, action);
864 if (action_ret == IRQ_HANDLED)
865 atomic_inc(&desc->threads_handled);
867 wake_threads_waitq(desc);
871 * This is the regular exit path. __free_irq() is stopping the
872 * thread via kthread_stop() after calling
873 * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
874 * oneshot mask bit can be set. We cannot verify that as we
875 * cannot touch the oneshot mask at this point anymore as
876 * __setup_irq() might have given out currents thread_mask
879 task_work_cancel(current, irq_thread_dtor);
883 static void irq_setup_forced_threading(struct irqaction *new)
885 if (!force_irqthreads)
887 if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
890 new->flags |= IRQF_ONESHOT;
892 if (!new->thread_fn) {
893 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
894 new->thread_fn = new->handler;
895 new->handler = irq_default_primary_handler;
900 * Internal function to register an irqaction - typically used to
901 * allocate special interrupts that are part of the architecture.
904 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
906 struct irqaction *old, **old_ptr;
907 unsigned long flags, thread_mask = 0;
908 int ret, nested, shared = 0;
914 if (desc->irq_data.chip == &no_irq_chip)
916 if (!try_module_get(desc->owner))
920 * Check whether the interrupt nests into another interrupt
923 nested = irq_settings_is_nested_thread(desc);
925 if (!new->thread_fn) {
930 * Replace the primary handler which was provided from
931 * the driver for non nested interrupt handling by the
932 * dummy function which warns when called.
934 new->handler = irq_nested_primary_handler;
936 if (irq_settings_can_thread(desc))
937 irq_setup_forced_threading(new);
941 * Create a handler thread when a thread function is supplied
942 * and the interrupt does not nest into another interrupt
945 if (new->thread_fn && !nested) {
946 struct task_struct *t;
948 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
955 * We keep the reference to the task struct even if
956 * the thread dies to avoid that the interrupt code
957 * references an already freed task_struct.
962 * Tell the thread to set its affinity. This is
963 * important for shared interrupt handlers as we do
964 * not invoke setup_affinity() for the secondary
965 * handlers as everything is already set up. Even for
966 * interrupts marked with IRQF_NO_BALANCE this is
967 * correct as we want the thread to move to the cpu(s)
968 * on which the requesting code placed the interrupt.
970 set_bit(IRQTF_AFFINITY, &new->thread_flags);
973 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
979 * Drivers are often written to work w/o knowledge about the
980 * underlying irq chip implementation, so a request for a
981 * threaded irq without a primary hard irq context handler
982 * requires the ONESHOT flag to be set. Some irq chips like
983 * MSI based interrupts are per se one shot safe. Check the
984 * chip flags, so we can avoid the unmask dance at the end of
985 * the threaded handler for those.
987 if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
988 new->flags &= ~IRQF_ONESHOT;
991 * The following block of code has to be executed atomically
993 raw_spin_lock_irqsave(&desc->lock, flags);
994 old_ptr = &desc->action;
998 * Can't share interrupts unless both agree to and are
999 * the same type (level, edge, polarity). So both flag
1000 * fields must have IRQF_SHARED set and the bits which
1001 * set the trigger type must match. Also all must
1004 if (!((old->flags & new->flags) & IRQF_SHARED) ||
1005 ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
1006 ((old->flags ^ new->flags) & IRQF_ONESHOT))
1009 /* All handlers must agree on per-cpuness */
1010 if ((old->flags & IRQF_PERCPU) !=
1011 (new->flags & IRQF_PERCPU))
1014 /* add new interrupt at end of irq queue */
1017 * Or all existing action->thread_mask bits,
1018 * so we can find the next zero bit for this
1021 thread_mask |= old->thread_mask;
1022 old_ptr = &old->next;
1029 * Setup the thread mask for this irqaction for ONESHOT. For
1030 * !ONESHOT irqs the thread mask is 0 so we can avoid a
1031 * conditional in irq_wake_thread().
1033 if (new->flags & IRQF_ONESHOT) {
1035 * Unlikely to have 32 resp 64 irqs sharing one line,
1038 if (thread_mask == ~0UL) {
1043 * The thread_mask for the action is or'ed to
1044 * desc->thread_active to indicate that the
1045 * IRQF_ONESHOT thread handler has been woken, but not
1046 * yet finished. The bit is cleared when a thread
1047 * completes. When all threads of a shared interrupt
1048 * line have completed desc->threads_active becomes
1049 * zero and the interrupt line is unmasked. See
1050 * handle.c:irq_wake_thread() for further information.
1052 * If no thread is woken by primary (hard irq context)
1053 * interrupt handlers, then desc->threads_active is
1054 * also checked for zero to unmask the irq line in the
1055 * affected hard irq flow handlers
1056 * (handle_[fasteoi|level]_irq).
1058 * The new action gets the first zero bit of
1059 * thread_mask assigned. See the loop above which or's
1060 * all existing action->thread_mask bits.
1062 new->thread_mask = 1 << ffz(thread_mask);
1064 } else if (new->handler == irq_default_primary_handler &&
1065 !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
1067 * The interrupt was requested with handler = NULL, so
1068 * we use the default primary handler for it. But it
1069 * does not have the oneshot flag set. In combination
1070 * with level interrupts this is deadly, because the
1071 * default primary handler just wakes the thread, then
1072 * the irq lines is reenabled, but the device still
1073 * has the level irq asserted. Rinse and repeat....
1075 * While this works for edge type interrupts, we play
1076 * it safe and reject unconditionally because we can't
1077 * say for sure which type this interrupt really
1078 * has. The type flags are unreliable as the
1079 * underlying chip implementation can override them.
1081 pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1088 init_waitqueue_head(&desc->wait_for_threads);
1090 /* Setup the type (level, edge polarity) if configured: */
1091 if (new->flags & IRQF_TRIGGER_MASK) {
1092 ret = __irq_set_trigger(desc, irq,
1093 new->flags & IRQF_TRIGGER_MASK);
1099 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1100 IRQS_ONESHOT | IRQS_WAITING);
1101 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1103 if (new->flags & IRQF_PERCPU) {
1104 irqd_set(&desc->irq_data, IRQD_PER_CPU);
1105 irq_settings_set_per_cpu(desc);
1108 if (new->flags & IRQF_ONESHOT)
1109 desc->istate |= IRQS_ONESHOT;
1111 if (irq_settings_can_autoenable(desc))
1112 irq_startup(desc, true);
1114 /* Undo nested disables: */
1117 /* Exclude IRQ from balancing if requested */
1118 if (new->flags & IRQF_NOBALANCING) {
1119 irq_settings_set_no_balancing(desc);
1120 irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1123 /* Set default affinity mask once everything is setup */
1124 setup_affinity(irq, desc, mask);
1126 } else if (new->flags & IRQF_TRIGGER_MASK) {
1127 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1128 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1131 /* hope the handler works with current trigger mode */
1132 pr_warning("irq %d uses trigger mode %u; requested %u\n",
1139 /* Reset broken irq detection when installing new handler */
1140 desc->irq_count = 0;
1141 desc->irqs_unhandled = 0;
1144 * Check whether we disabled the irq via the spurious handler
1145 * before. Reenable it and give it another chance.
1147 if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1148 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1149 __enable_irq(desc, irq, false);
1152 raw_spin_unlock_irqrestore(&desc->lock, flags);
1155 * Strictly no need to wake it up, but hung_task complains
1156 * when no hard interrupt wakes the thread up.
1159 wake_up_process(new->thread);
1161 register_irq_proc(irq, desc);
1163 register_handler_proc(irq, new);
1164 free_cpumask_var(mask);
1169 if (!(new->flags & IRQF_PROBE_SHARED)) {
1170 pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1171 irq, new->flags, new->name, old->flags, old->name);
1172 #ifdef CONFIG_DEBUG_SHIRQ
1179 raw_spin_unlock_irqrestore(&desc->lock, flags);
1180 free_cpumask_var(mask);
1184 struct task_struct *t = new->thread;
1191 module_put(desc->owner);
1196 * setup_irq - setup an interrupt
1197 * @irq: Interrupt line to setup
1198 * @act: irqaction for the interrupt
1200 * Used to statically setup interrupts in the early boot process.
1202 int setup_irq(unsigned int irq, struct irqaction *act)
1205 struct irq_desc *desc = irq_to_desc(irq);
1207 if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1209 chip_bus_lock(desc);
1210 retval = __setup_irq(irq, desc, act);
1211 chip_bus_sync_unlock(desc);
1215 EXPORT_SYMBOL_GPL(setup_irq);
1218 * Internal function to unregister an irqaction - used to free
1219 * regular and special interrupts that are part of the architecture.
1221 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1223 struct irq_desc *desc = irq_to_desc(irq);
1224 struct irqaction *action, **action_ptr;
1225 unsigned long flags;
1227 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1232 raw_spin_lock_irqsave(&desc->lock, flags);
1235 * There can be multiple actions per IRQ descriptor, find the right
1236 * one based on the dev_id:
1238 action_ptr = &desc->action;
1240 action = *action_ptr;
1243 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1244 raw_spin_unlock_irqrestore(&desc->lock, flags);
1249 if (action->dev_id == dev_id)
1251 action_ptr = &action->next;
1254 /* Found it - now remove it from the list of entries: */
1255 *action_ptr = action->next;
1257 /* If this was the last handler, shut down the IRQ line: */
1262 /* make sure affinity_hint is cleaned up */
1263 if (WARN_ON_ONCE(desc->affinity_hint))
1264 desc->affinity_hint = NULL;
1267 raw_spin_unlock_irqrestore(&desc->lock, flags);
1269 unregister_handler_proc(irq, action);
1271 /* Make sure it's not being used on another CPU: */
1272 synchronize_irq(irq);
1274 #ifdef CONFIG_DEBUG_SHIRQ
1276 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1277 * event to happen even now it's being freed, so let's make sure that
1278 * is so by doing an extra call to the handler ....
1280 * ( We do this after actually deregistering it, to make sure that a
1281 * 'real' IRQ doesn't run in * parallel with our fake. )
1283 if (action->flags & IRQF_SHARED) {
1284 local_irq_save(flags);
1285 action->handler(irq, dev_id);
1286 local_irq_restore(flags);
1290 if (action->thread) {
1291 kthread_stop(action->thread);
1292 put_task_struct(action->thread);
1295 module_put(desc->owner);
1300 * remove_irq - free an interrupt
1301 * @irq: Interrupt line to free
1302 * @act: irqaction for the interrupt
1304 * Used to remove interrupts statically setup by the early boot process.
1306 void remove_irq(unsigned int irq, struct irqaction *act)
1308 struct irq_desc *desc = irq_to_desc(irq);
1310 if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1311 __free_irq(irq, act->dev_id);
1313 EXPORT_SYMBOL_GPL(remove_irq);
1316 * free_irq - free an interrupt allocated with request_irq
1317 * @irq: Interrupt line to free
1318 * @dev_id: Device identity to free
1320 * Remove an interrupt handler. The handler is removed and if the
1321 * interrupt line is no longer in use by any driver it is disabled.
1322 * On a shared IRQ the caller must ensure the interrupt is disabled
1323 * on the card it drives before calling this function. The function
1324 * does not return until any executing interrupts for this IRQ
1327 * This function must not be called from interrupt context.
1329 void free_irq(unsigned int irq, void *dev_id)
1331 struct irq_desc *desc = irq_to_desc(irq);
1333 if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1337 if (WARN_ON(desc->affinity_notify))
1338 desc->affinity_notify = NULL;
1341 chip_bus_lock(desc);
1342 kfree(__free_irq(irq, dev_id));
1343 chip_bus_sync_unlock(desc);
1345 EXPORT_SYMBOL(free_irq);
1348 * request_threaded_irq - allocate an interrupt line
1349 * @irq: Interrupt line to allocate
1350 * @handler: Function to be called when the IRQ occurs.
1351 * Primary handler for threaded interrupts
1352 * If NULL and thread_fn != NULL the default
1353 * primary handler is installed
1354 * @thread_fn: Function called from the irq handler thread
1355 * If NULL, no irq thread is created
1356 * @irqflags: Interrupt type flags
1357 * @devname: An ascii name for the claiming device
1358 * @dev_id: A cookie passed back to the handler function
1360 * This call allocates interrupt resources and enables the
1361 * interrupt line and IRQ handling. From the point this
1362 * call is made your handler function may be invoked. Since
1363 * your handler function must clear any interrupt the board
1364 * raises, you must take care both to initialise your hardware
1365 * and to set up the interrupt handler in the right order.
1367 * If you want to set up a threaded irq handler for your device
1368 * then you need to supply @handler and @thread_fn. @handler is
1369 * still called in hard interrupt context and has to check
1370 * whether the interrupt originates from the device. If yes it
1371 * needs to disable the interrupt on the device and return
1372 * IRQ_WAKE_THREAD which will wake up the handler thread and run
1373 * @thread_fn. This split handler design is necessary to support
1374 * shared interrupts.
1376 * Dev_id must be globally unique. Normally the address of the
1377 * device data structure is used as the cookie. Since the handler
1378 * receives this value it makes sense to use it.
1380 * If your interrupt is shared you must pass a non NULL dev_id
1381 * as this is required when freeing the interrupt.
1385 * IRQF_SHARED Interrupt is shared
1386 * IRQF_TRIGGER_* Specify active edge(s) or level
1389 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1390 irq_handler_t thread_fn, unsigned long irqflags,
1391 const char *devname, void *dev_id)
1393 struct irqaction *action;
1394 struct irq_desc *desc;
1398 * Sanity-check: shared interrupts must pass in a real dev-ID,
1399 * otherwise we'll have trouble later trying to figure out
1400 * which interrupt is which (messes up the interrupt freeing
1403 if ((irqflags & IRQF_SHARED) && !dev_id)
1406 desc = irq_to_desc(irq);
1410 if (!irq_settings_can_request(desc) ||
1411 WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1417 handler = irq_default_primary_handler;
1420 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1424 action->handler = handler;
1425 action->thread_fn = thread_fn;
1426 action->flags = irqflags;
1427 action->name = devname;
1428 action->dev_id = dev_id;
1430 chip_bus_lock(desc);
1431 retval = __setup_irq(irq, desc, action);
1432 chip_bus_sync_unlock(desc);
1437 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1438 if (!retval && (irqflags & IRQF_SHARED)) {
1440 * It's a shared IRQ -- the driver ought to be prepared for it
1441 * to happen immediately, so let's make sure....
1442 * We disable the irq to make sure that a 'real' IRQ doesn't
1443 * run in parallel with our fake.
1445 unsigned long flags;
1448 local_irq_save(flags);
1450 handler(irq, dev_id);
1452 local_irq_restore(flags);
1458 EXPORT_SYMBOL(request_threaded_irq);
1461 * request_any_context_irq - allocate an interrupt line
1462 * @irq: Interrupt line to allocate
1463 * @handler: Function to be called when the IRQ occurs.
1464 * Threaded handler for threaded interrupts.
1465 * @flags: Interrupt type flags
1466 * @name: An ascii name for the claiming device
1467 * @dev_id: A cookie passed back to the handler function
1469 * This call allocates interrupt resources and enables the
1470 * interrupt line and IRQ handling. It selects either a
1471 * hardirq or threaded handling method depending on the
1474 * On failure, it returns a negative value. On success,
1475 * it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1477 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1478 unsigned long flags, const char *name, void *dev_id)
1480 struct irq_desc *desc = irq_to_desc(irq);
1486 if (irq_settings_is_nested_thread(desc)) {
1487 ret = request_threaded_irq(irq, NULL, handler,
1488 flags, name, dev_id);
1489 return !ret ? IRQC_IS_NESTED : ret;
1492 ret = request_irq(irq, handler, flags, name, dev_id);
1493 return !ret ? IRQC_IS_HARDIRQ : ret;
1495 EXPORT_SYMBOL_GPL(request_any_context_irq);
1497 void enable_percpu_irq(unsigned int irq, unsigned int type)
1499 unsigned int cpu = smp_processor_id();
1500 unsigned long flags;
1501 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1506 type &= IRQ_TYPE_SENSE_MASK;
1507 if (type != IRQ_TYPE_NONE) {
1510 ret = __irq_set_trigger(desc, irq, type);
1513 WARN(1, "failed to set type for IRQ%d\n", irq);
1518 irq_percpu_enable(desc, cpu);
1520 irq_put_desc_unlock(desc, flags);
1522 EXPORT_SYMBOL_GPL(enable_percpu_irq);
1524 void disable_percpu_irq(unsigned int irq)
1526 unsigned int cpu = smp_processor_id();
1527 unsigned long flags;
1528 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1533 irq_percpu_disable(desc, cpu);
1534 irq_put_desc_unlock(desc, flags);
1536 EXPORT_SYMBOL_GPL(disable_percpu_irq);
1539 * Internal function to unregister a percpu irqaction.
1541 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1543 struct irq_desc *desc = irq_to_desc(irq);
1544 struct irqaction *action;
1545 unsigned long flags;
1547 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1552 raw_spin_lock_irqsave(&desc->lock, flags);
1554 action = desc->action;
1555 if (!action || action->percpu_dev_id != dev_id) {
1556 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1560 if (!cpumask_empty(desc->percpu_enabled)) {
1561 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1562 irq, cpumask_first(desc->percpu_enabled));
1566 /* Found it - now remove it from the list of entries: */
1567 desc->action = NULL;
1569 raw_spin_unlock_irqrestore(&desc->lock, flags);
1571 unregister_handler_proc(irq, action);
1573 module_put(desc->owner);
1577 raw_spin_unlock_irqrestore(&desc->lock, flags);
1582 * remove_percpu_irq - free a per-cpu interrupt
1583 * @irq: Interrupt line to free
1584 * @act: irqaction for the interrupt
1586 * Used to remove interrupts statically setup by the early boot process.
1588 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1590 struct irq_desc *desc = irq_to_desc(irq);
1592 if (desc && irq_settings_is_per_cpu_devid(desc))
1593 __free_percpu_irq(irq, act->percpu_dev_id);
1597 * free_percpu_irq - free an interrupt allocated with request_percpu_irq
1598 * @irq: Interrupt line to free
1599 * @dev_id: Device identity to free
1601 * Remove a percpu interrupt handler. The handler is removed, but
1602 * the interrupt line is not disabled. This must be done on each
1603 * CPU before calling this function. The function does not return
1604 * until any executing interrupts for this IRQ have completed.
1606 * This function must not be called from interrupt context.
1608 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1610 struct irq_desc *desc = irq_to_desc(irq);
1612 if (!desc || !irq_settings_is_per_cpu_devid(desc))
1615 chip_bus_lock(desc);
1616 kfree(__free_percpu_irq(irq, dev_id));
1617 chip_bus_sync_unlock(desc);
1621 * setup_percpu_irq - setup a per-cpu interrupt
1622 * @irq: Interrupt line to setup
1623 * @act: irqaction for the interrupt
1625 * Used to statically setup per-cpu interrupts in the early boot process.
1627 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1629 struct irq_desc *desc = irq_to_desc(irq);
1632 if (!desc || !irq_settings_is_per_cpu_devid(desc))
1634 chip_bus_lock(desc);
1635 retval = __setup_irq(irq, desc, act);
1636 chip_bus_sync_unlock(desc);
1642 * request_percpu_irq - allocate a percpu interrupt line
1643 * @irq: Interrupt line to allocate
1644 * @handler: Function to be called when the IRQ occurs.
1645 * @devname: An ascii name for the claiming device
1646 * @dev_id: A percpu cookie passed back to the handler function
1648 * This call allocates interrupt resources, but doesn't
1649 * automatically enable the interrupt. It has to be done on each
1650 * CPU using enable_percpu_irq().
1652 * Dev_id must be globally unique. It is a per-cpu variable, and
1653 * the handler gets called with the interrupted CPU's instance of
1656 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1657 const char *devname, void __percpu *dev_id)
1659 struct irqaction *action;
1660 struct irq_desc *desc;
1666 desc = irq_to_desc(irq);
1667 if (!desc || !irq_settings_can_request(desc) ||
1668 !irq_settings_is_per_cpu_devid(desc))
1671 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1675 action->handler = handler;
1676 action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1677 action->name = devname;
1678 action->percpu_dev_id = dev_id;
1680 chip_bus_lock(desc);
1681 retval = __setup_irq(irq, desc, action);
1682 chip_bus_sync_unlock(desc);