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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
4 * Copyright (C) 2005-2006 Thomas Gleixner
5 *
6 * This file contains driver APIs to the irq subsystem.
7 */
8
9#define pr_fmt(fmt) "genirq: " fmt
10
11#include <linux/irq.h>
12#include <linux/kthread.h>
13#include <linux/module.h>
14#include <linux/random.h>
15#include <linux/interrupt.h>
16#include <linux/irqdomain.h>
17#include <linux/slab.h>
18#include <linux/sched.h>
19#include <linux/sched/rt.h>
20#include <linux/sched/task.h>
21#include <linux/sched/isolation.h>
22#include <uapi/linux/sched/types.h>
23#include <linux/task_work.h>
24
25#include "internals.h"
26
27#if defined(CONFIG_IRQ_FORCED_THREADING) && !defined(CONFIG_PREEMPT_RT)
28DEFINE_STATIC_KEY_FALSE(force_irqthreads_key);
29
30static int __init setup_forced_irqthreads(char *arg)
31{
32 static_branch_enable(&force_irqthreads_key);
33 return 0;
34}
35early_param("threadirqs", setup_forced_irqthreads);
36#endif
37
38static void __synchronize_hardirq(struct irq_desc *desc, bool sync_chip)
39{
40 struct irq_data *irqd = irq_desc_get_irq_data(desc);
41 bool inprogress;
42
43 do {
44 unsigned long flags;
45
46 /*
47 * Wait until we're out of the critical section. This might
48 * give the wrong answer due to the lack of memory barriers.
49 */
50 while (irqd_irq_inprogress(&desc->irq_data))
51 cpu_relax();
52
53 /* Ok, that indicated we're done: double-check carefully. */
54 raw_spin_lock_irqsave(&desc->lock, flags);
55 inprogress = irqd_irq_inprogress(&desc->irq_data);
56
57 /*
58 * If requested and supported, check at the chip whether it
59 * is in flight at the hardware level, i.e. already pending
60 * in a CPU and waiting for service and acknowledge.
61 */
62 if (!inprogress && sync_chip) {
63 /*
64 * Ignore the return code. inprogress is only updated
65 * when the chip supports it.
66 */
67 __irq_get_irqchip_state(irqd, IRQCHIP_STATE_ACTIVE,
68 &inprogress);
69 }
70 raw_spin_unlock_irqrestore(&desc->lock, flags);
71
72 /* Oops, that failed? */
73 } while (inprogress);
74}
75
76/**
77 * synchronize_hardirq - wait for pending hard IRQ handlers (on other CPUs)
78 * @irq: interrupt number to wait for
79 *
80 * This function waits for any pending hard IRQ handlers for this
81 * interrupt to complete before returning. If you use this
82 * function while holding a resource the IRQ handler may need you
83 * will deadlock. It does not take associated threaded handlers
84 * into account.
85 *
86 * Do not use this for shutdown scenarios where you must be sure
87 * that all parts (hardirq and threaded handler) have completed.
88 *
89 * Returns: false if a threaded handler is active.
90 *
91 * This function may be called - with care - from IRQ context.
92 *
93 * It does not check whether there is an interrupt in flight at the
94 * hardware level, but not serviced yet, as this might deadlock when
95 * called with interrupts disabled and the target CPU of the interrupt
96 * is the current CPU.
97 */
98bool synchronize_hardirq(unsigned int irq)
99{
100 struct irq_desc *desc = irq_to_desc(irq);
101
102 if (desc) {
103 __synchronize_hardirq(desc, false);
104 return !atomic_read(&desc->threads_active);
105 }
106
107 return true;
108}
109EXPORT_SYMBOL(synchronize_hardirq);
110
111static void __synchronize_irq(struct irq_desc *desc)
112{
113 __synchronize_hardirq(desc, true);
114 /*
115 * We made sure that no hardirq handler is running. Now verify that no
116 * threaded handlers are active.
117 */
118 wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
119}
120
121/**
122 * synchronize_irq - wait for pending IRQ handlers (on other CPUs)
123 * @irq: interrupt number to wait for
124 *
125 * This function waits for any pending IRQ handlers for this interrupt
126 * to complete before returning. If you use this function while
127 * holding a resource the IRQ handler may need you will deadlock.
128 *
129 * Can only be called from preemptible code as it might sleep when
130 * an interrupt thread is associated to @irq.
131 *
132 * It optionally makes sure (when the irq chip supports that method)
133 * that the interrupt is not pending in any CPU and waiting for
134 * service.
135 */
136void synchronize_irq(unsigned int irq)
137{
138 struct irq_desc *desc = irq_to_desc(irq);
139
140 if (desc)
141 __synchronize_irq(desc);
142}
143EXPORT_SYMBOL(synchronize_irq);
144
145#ifdef CONFIG_SMP
146cpumask_var_t irq_default_affinity;
147
148static bool __irq_can_set_affinity(struct irq_desc *desc)
149{
150 if (!desc || !irqd_can_balance(&desc->irq_data) ||
151 !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
152 return false;
153 return true;
154}
155
156/**
157 * irq_can_set_affinity - Check if the affinity of a given irq can be set
158 * @irq: Interrupt to check
159 *
160 */
161int irq_can_set_affinity(unsigned int irq)
162{
163 return __irq_can_set_affinity(irq_to_desc(irq));
164}
165
166/**
167 * irq_can_set_affinity_usr - Check if affinity of a irq can be set from user space
168 * @irq: Interrupt to check
169 *
170 * Like irq_can_set_affinity() above, but additionally checks for the
171 * AFFINITY_MANAGED flag.
172 */
173bool irq_can_set_affinity_usr(unsigned int irq)
174{
175 struct irq_desc *desc = irq_to_desc(irq);
176
177 return __irq_can_set_affinity(desc) &&
178 !irqd_affinity_is_managed(&desc->irq_data);
179}
180
181/**
182 * irq_set_thread_affinity - Notify irq threads to adjust affinity
183 * @desc: irq descriptor which has affinity changed
184 *
185 * We just set IRQTF_AFFINITY and delegate the affinity setting
186 * to the interrupt thread itself. We can not call
187 * set_cpus_allowed_ptr() here as we hold desc->lock and this
188 * code can be called from hard interrupt context.
189 */
190void irq_set_thread_affinity(struct irq_desc *desc)
191{
192 struct irqaction *action;
193
194 for_each_action_of_desc(desc, action) {
195 if (action->thread) {
196 set_bit(IRQTF_AFFINITY, &action->thread_flags);
197 wake_up_process(action->thread);
198 }
199 if (action->secondary && action->secondary->thread) {
200 set_bit(IRQTF_AFFINITY, &action->secondary->thread_flags);
201 wake_up_process(action->secondary->thread);
202 }
203 }
204}
205
206#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
207static void irq_validate_effective_affinity(struct irq_data *data)
208{
209 const struct cpumask *m = irq_data_get_effective_affinity_mask(data);
210 struct irq_chip *chip = irq_data_get_irq_chip(data);
211
212 if (!cpumask_empty(m))
213 return;
214 pr_warn_once("irq_chip %s did not update eff. affinity mask of irq %u\n",
215 chip->name, data->irq);
216}
217#else
218static inline void irq_validate_effective_affinity(struct irq_data *data) { }
219#endif
220
221int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
222 bool force)
223{
224 struct irq_desc *desc = irq_data_to_desc(data);
225 struct irq_chip *chip = irq_data_get_irq_chip(data);
226 const struct cpumask *prog_mask;
227 int ret;
228
229 static DEFINE_RAW_SPINLOCK(tmp_mask_lock);
230 static struct cpumask tmp_mask;
231
232 if (!chip || !chip->irq_set_affinity)
233 return -EINVAL;
234
235 raw_spin_lock(&tmp_mask_lock);
236 /*
237 * If this is a managed interrupt and housekeeping is enabled on
238 * it check whether the requested affinity mask intersects with
239 * a housekeeping CPU. If so, then remove the isolated CPUs from
240 * the mask and just keep the housekeeping CPU(s). This prevents
241 * the affinity setter from routing the interrupt to an isolated
242 * CPU to avoid that I/O submitted from a housekeeping CPU causes
243 * interrupts on an isolated one.
244 *
245 * If the masks do not intersect or include online CPU(s) then
246 * keep the requested mask. The isolated target CPUs are only
247 * receiving interrupts when the I/O operation was submitted
248 * directly from them.
249 *
250 * If all housekeeping CPUs in the affinity mask are offline, the
251 * interrupt will be migrated by the CPU hotplug code once a
252 * housekeeping CPU which belongs to the affinity mask comes
253 * online.
254 */
255 if (irqd_affinity_is_managed(data) &&
256 housekeeping_enabled(HK_TYPE_MANAGED_IRQ)) {
257 const struct cpumask *hk_mask;
258
259 hk_mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ);
260
261 cpumask_and(&tmp_mask, mask, hk_mask);
262 if (!cpumask_intersects(&tmp_mask, cpu_online_mask))
263 prog_mask = mask;
264 else
265 prog_mask = &tmp_mask;
266 } else {
267 prog_mask = mask;
268 }
269
270 /*
271 * Make sure we only provide online CPUs to the irqchip,
272 * unless we are being asked to force the affinity (in which
273 * case we do as we are told).
274 */
275 cpumask_and(&tmp_mask, prog_mask, cpu_online_mask);
276 if (!force && !cpumask_empty(&tmp_mask))
277 ret = chip->irq_set_affinity(data, &tmp_mask, force);
278 else if (force)
279 ret = chip->irq_set_affinity(data, mask, force);
280 else
281 ret = -EINVAL;
282
283 raw_spin_unlock(&tmp_mask_lock);
284
285 switch (ret) {
286 case IRQ_SET_MASK_OK:
287 case IRQ_SET_MASK_OK_DONE:
288 cpumask_copy(desc->irq_common_data.affinity, mask);
289 fallthrough;
290 case IRQ_SET_MASK_OK_NOCOPY:
291 irq_validate_effective_affinity(data);
292 irq_set_thread_affinity(desc);
293 ret = 0;
294 }
295
296 return ret;
297}
298
299#ifdef CONFIG_GENERIC_PENDING_IRQ
300static inline int irq_set_affinity_pending(struct irq_data *data,
301 const struct cpumask *dest)
302{
303 struct irq_desc *desc = irq_data_to_desc(data);
304
305 irqd_set_move_pending(data);
306 irq_copy_pending(desc, dest);
307 return 0;
308}
309#else
310static inline int irq_set_affinity_pending(struct irq_data *data,
311 const struct cpumask *dest)
312{
313 return -EBUSY;
314}
315#endif
316
317static int irq_try_set_affinity(struct irq_data *data,
318 const struct cpumask *dest, bool force)
319{
320 int ret = irq_do_set_affinity(data, dest, force);
321
322 /*
323 * In case that the underlying vector management is busy and the
324 * architecture supports the generic pending mechanism then utilize
325 * this to avoid returning an error to user space.
326 */
327 if (ret == -EBUSY && !force)
328 ret = irq_set_affinity_pending(data, dest);
329 return ret;
330}
331
332static bool irq_set_affinity_deactivated(struct irq_data *data,
333 const struct cpumask *mask)
334{
335 struct irq_desc *desc = irq_data_to_desc(data);
336
337 /*
338 * Handle irq chips which can handle affinity only in activated
339 * state correctly
340 *
341 * If the interrupt is not yet activated, just store the affinity
342 * mask and do not call the chip driver at all. On activation the
343 * driver has to make sure anyway that the interrupt is in a
344 * usable state so startup works.
345 */
346 if (!IS_ENABLED(CONFIG_IRQ_DOMAIN_HIERARCHY) ||
347 irqd_is_activated(data) || !irqd_affinity_on_activate(data))
348 return false;
349
350 cpumask_copy(desc->irq_common_data.affinity, mask);
351 irq_data_update_effective_affinity(data, mask);
352 irqd_set(data, IRQD_AFFINITY_SET);
353 return true;
354}
355
356int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
357 bool force)
358{
359 struct irq_chip *chip = irq_data_get_irq_chip(data);
360 struct irq_desc *desc = irq_data_to_desc(data);
361 int ret = 0;
362
363 if (!chip || !chip->irq_set_affinity)
364 return -EINVAL;
365
366 if (irq_set_affinity_deactivated(data, mask))
367 return 0;
368
369 if (irq_can_move_pcntxt(data) && !irqd_is_setaffinity_pending(data)) {
370 ret = irq_try_set_affinity(data, mask, force);
371 } else {
372 irqd_set_move_pending(data);
373 irq_copy_pending(desc, mask);
374 }
375
376 if (desc->affinity_notify) {
377 kref_get(&desc->affinity_notify->kref);
378 if (!schedule_work(&desc->affinity_notify->work)) {
379 /* Work was already scheduled, drop our extra ref */
380 kref_put(&desc->affinity_notify->kref,
381 desc->affinity_notify->release);
382 }
383 }
384 irqd_set(data, IRQD_AFFINITY_SET);
385
386 return ret;
387}
388
389/**
390 * irq_update_affinity_desc - Update affinity management for an interrupt
391 * @irq: The interrupt number to update
392 * @affinity: Pointer to the affinity descriptor
393 *
394 * This interface can be used to configure the affinity management of
395 * interrupts which have been allocated already.
396 *
397 * There are certain limitations on when it may be used - attempts to use it
398 * for when the kernel is configured for generic IRQ reservation mode (in
399 * config GENERIC_IRQ_RESERVATION_MODE) will fail, as it may conflict with
400 * managed/non-managed interrupt accounting. In addition, attempts to use it on
401 * an interrupt which is already started or which has already been configured
402 * as managed will also fail, as these mean invalid init state or double init.
403 */
404int irq_update_affinity_desc(unsigned int irq,
405 struct irq_affinity_desc *affinity)
406{
407 struct irq_desc *desc;
408 unsigned long flags;
409 bool activated;
410 int ret = 0;
411
412 /*
413 * Supporting this with the reservation scheme used by x86 needs
414 * some more thought. Fail it for now.
415 */
416 if (IS_ENABLED(CONFIG_GENERIC_IRQ_RESERVATION_MODE))
417 return -EOPNOTSUPP;
418
419 desc = irq_get_desc_buslock(irq, &flags, 0);
420 if (!desc)
421 return -EINVAL;
422
423 /* Requires the interrupt to be shut down */
424 if (irqd_is_started(&desc->irq_data)) {
425 ret = -EBUSY;
426 goto out_unlock;
427 }
428
429 /* Interrupts which are already managed cannot be modified */
430 if (irqd_affinity_is_managed(&desc->irq_data)) {
431 ret = -EBUSY;
432 goto out_unlock;
433 }
434
435 /*
436 * Deactivate the interrupt. That's required to undo
437 * anything an earlier activation has established.
438 */
439 activated = irqd_is_activated(&desc->irq_data);
440 if (activated)
441 irq_domain_deactivate_irq(&desc->irq_data);
442
443 if (affinity->is_managed) {
444 irqd_set(&desc->irq_data, IRQD_AFFINITY_MANAGED);
445 irqd_set(&desc->irq_data, IRQD_MANAGED_SHUTDOWN);
446 }
447
448 cpumask_copy(desc->irq_common_data.affinity, &affinity->mask);
449
450 /* Restore the activation state */
451 if (activated)
452 irq_domain_activate_irq(&desc->irq_data, false);
453
454out_unlock:
455 irq_put_desc_busunlock(desc, flags);
456 return ret;
457}
458
459static int __irq_set_affinity(unsigned int irq, const struct cpumask *mask,
460 bool force)
461{
462 struct irq_desc *desc = irq_to_desc(irq);
463 unsigned long flags;
464 int ret;
465
466 if (!desc)
467 return -EINVAL;
468
469 raw_spin_lock_irqsave(&desc->lock, flags);
470 ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force);
471 raw_spin_unlock_irqrestore(&desc->lock, flags);
472 return ret;
473}
474
475/**
476 * irq_set_affinity - Set the irq affinity of a given irq
477 * @irq: Interrupt to set affinity
478 * @cpumask: cpumask
479 *
480 * Fails if cpumask does not contain an online CPU
481 */
482int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
483{
484 return __irq_set_affinity(irq, cpumask, false);
485}
486EXPORT_SYMBOL_GPL(irq_set_affinity);
487
488/**
489 * irq_force_affinity - Force the irq affinity of a given irq
490 * @irq: Interrupt to set affinity
491 * @cpumask: cpumask
492 *
493 * Same as irq_set_affinity, but without checking the mask against
494 * online cpus.
495 *
496 * Solely for low level cpu hotplug code, where we need to make per
497 * cpu interrupts affine before the cpu becomes online.
498 */
499int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask)
500{
501 return __irq_set_affinity(irq, cpumask, true);
502}
503EXPORT_SYMBOL_GPL(irq_force_affinity);
504
505int __irq_apply_affinity_hint(unsigned int irq, const struct cpumask *m,
506 bool setaffinity)
507{
508 unsigned long flags;
509 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
510
511 if (!desc)
512 return -EINVAL;
513 desc->affinity_hint = m;
514 irq_put_desc_unlock(desc, flags);
515 if (m && setaffinity)
516 __irq_set_affinity(irq, m, false);
517 return 0;
518}
519EXPORT_SYMBOL_GPL(__irq_apply_affinity_hint);
520
521static void irq_affinity_notify(struct work_struct *work)
522{
523 struct irq_affinity_notify *notify =
524 container_of(work, struct irq_affinity_notify, work);
525 struct irq_desc *desc = irq_to_desc(notify->irq);
526 cpumask_var_t cpumask;
527 unsigned long flags;
528
529 if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
530 goto out;
531
532 raw_spin_lock_irqsave(&desc->lock, flags);
533 if (irq_move_pending(&desc->irq_data))
534 irq_get_pending(cpumask, desc);
535 else
536 cpumask_copy(cpumask, desc->irq_common_data.affinity);
537 raw_spin_unlock_irqrestore(&desc->lock, flags);
538
539 notify->notify(notify, cpumask);
540
541 free_cpumask_var(cpumask);
542out:
543 kref_put(¬ify->kref, notify->release);
544}
545
546/**
547 * irq_set_affinity_notifier - control notification of IRQ affinity changes
548 * @irq: Interrupt for which to enable/disable notification
549 * @notify: Context for notification, or %NULL to disable
550 * notification. Function pointers must be initialised;
551 * the other fields will be initialised by this function.
552 *
553 * Must be called in process context. Notification may only be enabled
554 * after the IRQ is allocated and must be disabled before the IRQ is
555 * freed using free_irq().
556 */
557int
558irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
559{
560 struct irq_desc *desc = irq_to_desc(irq);
561 struct irq_affinity_notify *old_notify;
562 unsigned long flags;
563
564 /* The release function is promised process context */
565 might_sleep();
566
567 if (!desc || desc->istate & IRQS_NMI)
568 return -EINVAL;
569
570 /* Complete initialisation of *notify */
571 if (notify) {
572 notify->irq = irq;
573 kref_init(¬ify->kref);
574 INIT_WORK(¬ify->work, irq_affinity_notify);
575 }
576
577 raw_spin_lock_irqsave(&desc->lock, flags);
578 old_notify = desc->affinity_notify;
579 desc->affinity_notify = notify;
580 raw_spin_unlock_irqrestore(&desc->lock, flags);
581
582 if (old_notify) {
583 if (cancel_work_sync(&old_notify->work)) {
584 /* Pending work had a ref, put that one too */
585 kref_put(&old_notify->kref, old_notify->release);
586 }
587 kref_put(&old_notify->kref, old_notify->release);
588 }
589
590 return 0;
591}
592EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
593
594#ifndef CONFIG_AUTO_IRQ_AFFINITY
595/*
596 * Generic version of the affinity autoselector.
597 */
598int irq_setup_affinity(struct irq_desc *desc)
599{
600 struct cpumask *set = irq_default_affinity;
601 int ret, node = irq_desc_get_node(desc);
602 static DEFINE_RAW_SPINLOCK(mask_lock);
603 static struct cpumask mask;
604
605 /* Excludes PER_CPU and NO_BALANCE interrupts */
606 if (!__irq_can_set_affinity(desc))
607 return 0;
608
609 raw_spin_lock(&mask_lock);
610 /*
611 * Preserve the managed affinity setting and a userspace affinity
612 * setup, but make sure that one of the targets is online.
613 */
614 if (irqd_affinity_is_managed(&desc->irq_data) ||
615 irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
616 if (cpumask_intersects(desc->irq_common_data.affinity,
617 cpu_online_mask))
618 set = desc->irq_common_data.affinity;
619 else
620 irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
621 }
622
623 cpumask_and(&mask, cpu_online_mask, set);
624 if (cpumask_empty(&mask))
625 cpumask_copy(&mask, cpu_online_mask);
626
627 if (node != NUMA_NO_NODE) {
628 const struct cpumask *nodemask = cpumask_of_node(node);
629
630 /* make sure at least one of the cpus in nodemask is online */
631 if (cpumask_intersects(&mask, nodemask))
632 cpumask_and(&mask, &mask, nodemask);
633 }
634 ret = irq_do_set_affinity(&desc->irq_data, &mask, false);
635 raw_spin_unlock(&mask_lock);
636 return ret;
637}
638#else
639/* Wrapper for ALPHA specific affinity selector magic */
640int irq_setup_affinity(struct irq_desc *desc)
641{
642 return irq_select_affinity(irq_desc_get_irq(desc));
643}
644#endif /* CONFIG_AUTO_IRQ_AFFINITY */
645#endif /* CONFIG_SMP */
646
647
648/**
649 * irq_set_vcpu_affinity - Set vcpu affinity for the interrupt
650 * @irq: interrupt number to set affinity
651 * @vcpu_info: vCPU specific data or pointer to a percpu array of vCPU
652 * specific data for percpu_devid interrupts
653 *
654 * This function uses the vCPU specific data to set the vCPU
655 * affinity for an irq. The vCPU specific data is passed from
656 * outside, such as KVM. One example code path is as below:
657 * KVM -> IOMMU -> irq_set_vcpu_affinity().
658 */
659int irq_set_vcpu_affinity(unsigned int irq, void *vcpu_info)
660{
661 unsigned long flags;
662 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
663 struct irq_data *data;
664 struct irq_chip *chip;
665 int ret = -ENOSYS;
666
667 if (!desc)
668 return -EINVAL;
669
670 data = irq_desc_get_irq_data(desc);
671 do {
672 chip = irq_data_get_irq_chip(data);
673 if (chip && chip->irq_set_vcpu_affinity)
674 break;
675#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
676 data = data->parent_data;
677#else
678 data = NULL;
679#endif
680 } while (data);
681
682 if (data)
683 ret = chip->irq_set_vcpu_affinity(data, vcpu_info);
684 irq_put_desc_unlock(desc, flags);
685
686 return ret;
687}
688EXPORT_SYMBOL_GPL(irq_set_vcpu_affinity);
689
690void __disable_irq(struct irq_desc *desc)
691{
692 if (!desc->depth++)
693 irq_disable(desc);
694}
695
696static int __disable_irq_nosync(unsigned int irq)
697{
698 unsigned long flags;
699 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
700
701 if (!desc)
702 return -EINVAL;
703 __disable_irq(desc);
704 irq_put_desc_busunlock(desc, flags);
705 return 0;
706}
707
708/**
709 * disable_irq_nosync - disable an irq without waiting
710 * @irq: Interrupt to disable
711 *
712 * Disable the selected interrupt line. Disables and Enables are
713 * nested.
714 * Unlike disable_irq(), this function does not ensure existing
715 * instances of the IRQ handler have completed before returning.
716 *
717 * This function may be called from IRQ context.
718 */
719void disable_irq_nosync(unsigned int irq)
720{
721 __disable_irq_nosync(irq);
722}
723EXPORT_SYMBOL(disable_irq_nosync);
724
725/**
726 * disable_irq - disable an irq and wait for completion
727 * @irq: Interrupt to disable
728 *
729 * Disable the selected interrupt line. Enables and Disables are
730 * nested.
731 * This function waits for any pending IRQ handlers for this interrupt
732 * to complete before returning. If you use this function while
733 * holding a resource the IRQ handler may need you will deadlock.
734 *
735 * Can only be called from preemptible code as it might sleep when
736 * an interrupt thread is associated to @irq.
737 *
738 */
739void disable_irq(unsigned int irq)
740{
741 might_sleep();
742 if (!__disable_irq_nosync(irq))
743 synchronize_irq(irq);
744}
745EXPORT_SYMBOL(disable_irq);
746
747/**
748 * disable_hardirq - disables an irq and waits for hardirq completion
749 * @irq: Interrupt to disable
750 *
751 * Disable the selected interrupt line. Enables and Disables are
752 * nested.
753 * This function waits for any pending hard IRQ handlers for this
754 * interrupt to complete before returning. If you use this function while
755 * holding a resource the hard IRQ handler may need you will deadlock.
756 *
757 * When used to optimistically disable an interrupt from atomic context
758 * the return value must be checked.
759 *
760 * Returns: false if a threaded handler is active.
761 *
762 * This function may be called - with care - from IRQ context.
763 */
764bool disable_hardirq(unsigned int irq)
765{
766 if (!__disable_irq_nosync(irq))
767 return synchronize_hardirq(irq);
768
769 return false;
770}
771EXPORT_SYMBOL_GPL(disable_hardirq);
772
773/**
774 * disable_nmi_nosync - disable an nmi without waiting
775 * @irq: Interrupt to disable
776 *
777 * Disable the selected interrupt line. Disables and enables are
778 * nested.
779 * The interrupt to disable must have been requested through request_nmi.
780 * Unlike disable_nmi(), this function does not ensure existing
781 * instances of the IRQ handler have completed before returning.
782 */
783void disable_nmi_nosync(unsigned int irq)
784{
785 disable_irq_nosync(irq);
786}
787
788void __enable_irq(struct irq_desc *desc)
789{
790 switch (desc->depth) {
791 case 0:
792 err_out:
793 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n",
794 irq_desc_get_irq(desc));
795 break;
796 case 1: {
797 if (desc->istate & IRQS_SUSPENDED)
798 goto err_out;
799 /* Prevent probing on this irq: */
800 irq_settings_set_noprobe(desc);
801 /*
802 * Call irq_startup() not irq_enable() here because the
803 * interrupt might be marked NOAUTOEN. So irq_startup()
804 * needs to be invoked when it gets enabled the first
805 * time. If it was already started up, then irq_startup()
806 * will invoke irq_enable() under the hood.
807 */
808 irq_startup(desc, IRQ_RESEND, IRQ_START_FORCE);
809 break;
810 }
811 default:
812 desc->depth--;
813 }
814}
815
816/**
817 * enable_irq - enable handling of an irq
818 * @irq: Interrupt to enable
819 *
820 * Undoes the effect of one call to disable_irq(). If this
821 * matches the last disable, processing of interrupts on this
822 * IRQ line is re-enabled.
823 *
824 * This function may be called from IRQ context only when
825 * desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
826 */
827void enable_irq(unsigned int irq)
828{
829 unsigned long flags;
830 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
831
832 if (!desc)
833 return;
834 if (WARN(!desc->irq_data.chip,
835 KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
836 goto out;
837
838 __enable_irq(desc);
839out:
840 irq_put_desc_busunlock(desc, flags);
841}
842EXPORT_SYMBOL(enable_irq);
843
844/**
845 * enable_nmi - enable handling of an nmi
846 * @irq: Interrupt to enable
847 *
848 * The interrupt to enable must have been requested through request_nmi.
849 * Undoes the effect of one call to disable_nmi(). If this
850 * matches the last disable, processing of interrupts on this
851 * IRQ line is re-enabled.
852 */
853void enable_nmi(unsigned int irq)
854{
855 enable_irq(irq);
856}
857
858static int set_irq_wake_real(unsigned int irq, unsigned int on)
859{
860 struct irq_desc *desc = irq_to_desc(irq);
861 int ret = -ENXIO;
862
863 if (irq_desc_get_chip(desc)->flags & IRQCHIP_SKIP_SET_WAKE)
864 return 0;
865
866 if (desc->irq_data.chip->irq_set_wake)
867 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
868
869 return ret;
870}
871
872/**
873 * irq_set_irq_wake - control irq power management wakeup
874 * @irq: interrupt to control
875 * @on: enable/disable power management wakeup
876 *
877 * Enable/disable power management wakeup mode, which is
878 * disabled by default. Enables and disables must match,
879 * just as they match for non-wakeup mode support.
880 *
881 * Wakeup mode lets this IRQ wake the system from sleep
882 * states like "suspend to RAM".
883 *
884 * Note: irq enable/disable state is completely orthogonal
885 * to the enable/disable state of irq wake. An irq can be
886 * disabled with disable_irq() and still wake the system as
887 * long as the irq has wake enabled. If this does not hold,
888 * then the underlying irq chip and the related driver need
889 * to be investigated.
890 */
891int irq_set_irq_wake(unsigned int irq, unsigned int on)
892{
893 unsigned long flags;
894 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
895 int ret = 0;
896
897 if (!desc)
898 return -EINVAL;
899
900 /* Don't use NMIs as wake up interrupts please */
901 if (desc->istate & IRQS_NMI) {
902 ret = -EINVAL;
903 goto out_unlock;
904 }
905
906 /* wakeup-capable irqs can be shared between drivers that
907 * don't need to have the same sleep mode behaviors.
908 */
909 if (on) {
910 if (desc->wake_depth++ == 0) {
911 ret = set_irq_wake_real(irq, on);
912 if (ret)
913 desc->wake_depth = 0;
914 else
915 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
916 }
917 } else {
918 if (desc->wake_depth == 0) {
919 WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
920 } else if (--desc->wake_depth == 0) {
921 ret = set_irq_wake_real(irq, on);
922 if (ret)
923 desc->wake_depth = 1;
924 else
925 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
926 }
927 }
928
929out_unlock:
930 irq_put_desc_busunlock(desc, flags);
931 return ret;
932}
933EXPORT_SYMBOL(irq_set_irq_wake);
934
935/*
936 * Internal function that tells the architecture code whether a
937 * particular irq has been exclusively allocated or is available
938 * for driver use.
939 */
940int can_request_irq(unsigned int irq, unsigned long irqflags)
941{
942 unsigned long flags;
943 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
944 int canrequest = 0;
945
946 if (!desc)
947 return 0;
948
949 if (irq_settings_can_request(desc)) {
950 if (!desc->action ||
951 irqflags & desc->action->flags & IRQF_SHARED)
952 canrequest = 1;
953 }
954 irq_put_desc_unlock(desc, flags);
955 return canrequest;
956}
957
958int __irq_set_trigger(struct irq_desc *desc, unsigned long flags)
959{
960 struct irq_chip *chip = desc->irq_data.chip;
961 int ret, unmask = 0;
962
963 if (!chip || !chip->irq_set_type) {
964 /*
965 * IRQF_TRIGGER_* but the PIC does not support multiple
966 * flow-types?
967 */
968 pr_debug("No set_type function for IRQ %d (%s)\n",
969 irq_desc_get_irq(desc),
970 chip ? (chip->name ? : "unknown") : "unknown");
971 return 0;
972 }
973
974 if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
975 if (!irqd_irq_masked(&desc->irq_data))
976 mask_irq(desc);
977 if (!irqd_irq_disabled(&desc->irq_data))
978 unmask = 1;
979 }
980
981 /* Mask all flags except trigger mode */
982 flags &= IRQ_TYPE_SENSE_MASK;
983 ret = chip->irq_set_type(&desc->irq_data, flags);
984
985 switch (ret) {
986 case IRQ_SET_MASK_OK:
987 case IRQ_SET_MASK_OK_DONE:
988 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
989 irqd_set(&desc->irq_data, flags);
990 fallthrough;
991
992 case IRQ_SET_MASK_OK_NOCOPY:
993 flags = irqd_get_trigger_type(&desc->irq_data);
994 irq_settings_set_trigger_mask(desc, flags);
995 irqd_clear(&desc->irq_data, IRQD_LEVEL);
996 irq_settings_clr_level(desc);
997 if (flags & IRQ_TYPE_LEVEL_MASK) {
998 irq_settings_set_level(desc);
999 irqd_set(&desc->irq_data, IRQD_LEVEL);
1000 }
1001
1002 ret = 0;
1003 break;
1004 default:
1005 pr_err("Setting trigger mode %lu for irq %u failed (%pS)\n",
1006 flags, irq_desc_get_irq(desc), chip->irq_set_type);
1007 }
1008 if (unmask)
1009 unmask_irq(desc);
1010 return ret;
1011}
1012
1013#ifdef CONFIG_HARDIRQS_SW_RESEND
1014int irq_set_parent(int irq, int parent_irq)
1015{
1016 unsigned long flags;
1017 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
1018
1019 if (!desc)
1020 return -EINVAL;
1021
1022 desc->parent_irq = parent_irq;
1023
1024 irq_put_desc_unlock(desc, flags);
1025 return 0;
1026}
1027EXPORT_SYMBOL_GPL(irq_set_parent);
1028#endif
1029
1030/*
1031 * Default primary interrupt handler for threaded interrupts. Is
1032 * assigned as primary handler when request_threaded_irq is called
1033 * with handler == NULL. Useful for oneshot interrupts.
1034 */
1035static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
1036{
1037 return IRQ_WAKE_THREAD;
1038}
1039
1040/*
1041 * Primary handler for nested threaded interrupts. Should never be
1042 * called.
1043 */
1044static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
1045{
1046 WARN(1, "Primary handler called for nested irq %d\n", irq);
1047 return IRQ_NONE;
1048}
1049
1050static irqreturn_t irq_forced_secondary_handler(int irq, void *dev_id)
1051{
1052 WARN(1, "Secondary action handler called for irq %d\n", irq);
1053 return IRQ_NONE;
1054}
1055
1056#ifdef CONFIG_SMP
1057/*
1058 * Check whether we need to change the affinity of the interrupt thread.
1059 */
1060static void irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
1061{
1062 cpumask_var_t mask;
1063 bool valid = false;
1064
1065 if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
1066 return;
1067
1068 __set_current_state(TASK_RUNNING);
1069
1070 /*
1071 * In case we are out of memory we set IRQTF_AFFINITY again and
1072 * try again next time
1073 */
1074 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
1075 set_bit(IRQTF_AFFINITY, &action->thread_flags);
1076 return;
1077 }
1078
1079 raw_spin_lock_irq(&desc->lock);
1080 /*
1081 * This code is triggered unconditionally. Check the affinity
1082 * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
1083 */
1084 if (cpumask_available(desc->irq_common_data.affinity)) {
1085 const struct cpumask *m;
1086
1087 m = irq_data_get_effective_affinity_mask(&desc->irq_data);
1088 cpumask_copy(mask, m);
1089 valid = true;
1090 }
1091 raw_spin_unlock_irq(&desc->lock);
1092
1093 if (valid)
1094 set_cpus_allowed_ptr(current, mask);
1095 free_cpumask_var(mask);
1096}
1097#else
1098static inline void irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
1099#endif
1100
1101static int irq_wait_for_interrupt(struct irq_desc *desc,
1102 struct irqaction *action)
1103{
1104 for (;;) {
1105 set_current_state(TASK_INTERRUPTIBLE);
1106 irq_thread_check_affinity(desc, action);
1107
1108 if (kthread_should_stop()) {
1109 /* may need to run one last time */
1110 if (test_and_clear_bit(IRQTF_RUNTHREAD,
1111 &action->thread_flags)) {
1112 __set_current_state(TASK_RUNNING);
1113 return 0;
1114 }
1115 __set_current_state(TASK_RUNNING);
1116 return -1;
1117 }
1118
1119 if (test_and_clear_bit(IRQTF_RUNTHREAD,
1120 &action->thread_flags)) {
1121 __set_current_state(TASK_RUNNING);
1122 return 0;
1123 }
1124 schedule();
1125 }
1126}
1127
1128/*
1129 * Oneshot interrupts keep the irq line masked until the threaded
1130 * handler finished. unmask if the interrupt has not been disabled and
1131 * is marked MASKED.
1132 */
1133static void irq_finalize_oneshot(struct irq_desc *desc,
1134 struct irqaction *action)
1135{
1136 if (!(desc->istate & IRQS_ONESHOT) ||
1137 action->handler == irq_forced_secondary_handler)
1138 return;
1139again:
1140 chip_bus_lock(desc);
1141 raw_spin_lock_irq(&desc->lock);
1142
1143 /*
1144 * Implausible though it may be we need to protect us against
1145 * the following scenario:
1146 *
1147 * The thread is faster done than the hard interrupt handler
1148 * on the other CPU. If we unmask the irq line then the
1149 * interrupt can come in again and masks the line, leaves due
1150 * to IRQS_INPROGRESS and the irq line is masked forever.
1151 *
1152 * This also serializes the state of shared oneshot handlers
1153 * versus "desc->threads_oneshot |= action->thread_mask;" in
1154 * irq_wake_thread(). See the comment there which explains the
1155 * serialization.
1156 */
1157 if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
1158 raw_spin_unlock_irq(&desc->lock);
1159 chip_bus_sync_unlock(desc);
1160 cpu_relax();
1161 goto again;
1162 }
1163
1164 /*
1165 * Now check again, whether the thread should run. Otherwise
1166 * we would clear the threads_oneshot bit of this thread which
1167 * was just set.
1168 */
1169 if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
1170 goto out_unlock;
1171
1172 desc->threads_oneshot &= ~action->thread_mask;
1173
1174 if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
1175 irqd_irq_masked(&desc->irq_data))
1176 unmask_threaded_irq(desc);
1177
1178out_unlock:
1179 raw_spin_unlock_irq(&desc->lock);
1180 chip_bus_sync_unlock(desc);
1181}
1182
1183/*
1184 * Interrupts which are not explicitly requested as threaded
1185 * interrupts rely on the implicit bh/preempt disable of the hard irq
1186 * context. So we need to disable bh here to avoid deadlocks and other
1187 * side effects.
1188 */
1189static irqreturn_t
1190irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
1191{
1192 irqreturn_t ret;
1193
1194 local_bh_disable();
1195 if (!IS_ENABLED(CONFIG_PREEMPT_RT))
1196 local_irq_disable();
1197 ret = action->thread_fn(action->irq, action->dev_id);
1198 if (ret == IRQ_HANDLED)
1199 atomic_inc(&desc->threads_handled);
1200
1201 irq_finalize_oneshot(desc, action);
1202 if (!IS_ENABLED(CONFIG_PREEMPT_RT))
1203 local_irq_enable();
1204 local_bh_enable();
1205 return ret;
1206}
1207
1208/*
1209 * Interrupts explicitly requested as threaded interrupts want to be
1210 * preemptible - many of them need to sleep and wait for slow busses to
1211 * complete.
1212 */
1213static irqreturn_t irq_thread_fn(struct irq_desc *desc,
1214 struct irqaction *action)
1215{
1216 irqreturn_t ret;
1217
1218 ret = action->thread_fn(action->irq, action->dev_id);
1219 if (ret == IRQ_HANDLED)
1220 atomic_inc(&desc->threads_handled);
1221
1222 irq_finalize_oneshot(desc, action);
1223 return ret;
1224}
1225
1226void wake_threads_waitq(struct irq_desc *desc)
1227{
1228 if (atomic_dec_and_test(&desc->threads_active))
1229 wake_up(&desc->wait_for_threads);
1230}
1231
1232static void irq_thread_dtor(struct callback_head *unused)
1233{
1234 struct task_struct *tsk = current;
1235 struct irq_desc *desc;
1236 struct irqaction *action;
1237
1238 if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
1239 return;
1240
1241 action = kthread_data(tsk);
1242
1243 pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
1244 tsk->comm, tsk->pid, action->irq);
1245
1246
1247 desc = irq_to_desc(action->irq);
1248 /*
1249 * If IRQTF_RUNTHREAD is set, we need to decrement
1250 * desc->threads_active and wake possible waiters.
1251 */
1252 if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
1253 wake_threads_waitq(desc);
1254
1255 /* Prevent a stale desc->threads_oneshot */
1256 irq_finalize_oneshot(desc, action);
1257}
1258
1259static void irq_wake_secondary(struct irq_desc *desc, struct irqaction *action)
1260{
1261 struct irqaction *secondary = action->secondary;
1262
1263 if (WARN_ON_ONCE(!secondary))
1264 return;
1265
1266 raw_spin_lock_irq(&desc->lock);
1267 __irq_wake_thread(desc, secondary);
1268 raw_spin_unlock_irq(&desc->lock);
1269}
1270
1271/*
1272 * Internal function to notify that a interrupt thread is ready.
1273 */
1274static void irq_thread_set_ready(struct irq_desc *desc,
1275 struct irqaction *action)
1276{
1277 set_bit(IRQTF_READY, &action->thread_flags);
1278 wake_up(&desc->wait_for_threads);
1279}
1280
1281/*
1282 * Internal function to wake up a interrupt thread and wait until it is
1283 * ready.
1284 */
1285static void wake_up_and_wait_for_irq_thread_ready(struct irq_desc *desc,
1286 struct irqaction *action)
1287{
1288 if (!action || !action->thread)
1289 return;
1290
1291 wake_up_process(action->thread);
1292 wait_event(desc->wait_for_threads,
1293 test_bit(IRQTF_READY, &action->thread_flags));
1294}
1295
1296/*
1297 * Interrupt handler thread
1298 */
1299static int irq_thread(void *data)
1300{
1301 struct callback_head on_exit_work;
1302 struct irqaction *action = data;
1303 struct irq_desc *desc = irq_to_desc(action->irq);
1304 irqreturn_t (*handler_fn)(struct irq_desc *desc,
1305 struct irqaction *action);
1306
1307 irq_thread_set_ready(desc, action);
1308
1309 sched_set_fifo(current);
1310
1311 if (force_irqthreads() && test_bit(IRQTF_FORCED_THREAD,
1312 &action->thread_flags))
1313 handler_fn = irq_forced_thread_fn;
1314 else
1315 handler_fn = irq_thread_fn;
1316
1317 init_task_work(&on_exit_work, irq_thread_dtor);
1318 task_work_add(current, &on_exit_work, TWA_NONE);
1319
1320 while (!irq_wait_for_interrupt(desc, action)) {
1321 irqreturn_t action_ret;
1322
1323 action_ret = handler_fn(desc, action);
1324 if (action_ret == IRQ_WAKE_THREAD)
1325 irq_wake_secondary(desc, action);
1326
1327 wake_threads_waitq(desc);
1328 }
1329
1330 /*
1331 * This is the regular exit path. __free_irq() is stopping the
1332 * thread via kthread_stop() after calling
1333 * synchronize_hardirq(). So neither IRQTF_RUNTHREAD nor the
1334 * oneshot mask bit can be set.
1335 */
1336 task_work_cancel(current, irq_thread_dtor);
1337 return 0;
1338}
1339
1340/**
1341 * irq_wake_thread - wake the irq thread for the action identified by dev_id
1342 * @irq: Interrupt line
1343 * @dev_id: Device identity for which the thread should be woken
1344 *
1345 */
1346void irq_wake_thread(unsigned int irq, void *dev_id)
1347{
1348 struct irq_desc *desc = irq_to_desc(irq);
1349 struct irqaction *action;
1350 unsigned long flags;
1351
1352 if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1353 return;
1354
1355 raw_spin_lock_irqsave(&desc->lock, flags);
1356 for_each_action_of_desc(desc, action) {
1357 if (action->dev_id == dev_id) {
1358 if (action->thread)
1359 __irq_wake_thread(desc, action);
1360 break;
1361 }
1362 }
1363 raw_spin_unlock_irqrestore(&desc->lock, flags);
1364}
1365EXPORT_SYMBOL_GPL(irq_wake_thread);
1366
1367static int irq_setup_forced_threading(struct irqaction *new)
1368{
1369 if (!force_irqthreads())
1370 return 0;
1371 if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
1372 return 0;
1373
1374 /*
1375 * No further action required for interrupts which are requested as
1376 * threaded interrupts already
1377 */
1378 if (new->handler == irq_default_primary_handler)
1379 return 0;
1380
1381 new->flags |= IRQF_ONESHOT;
1382
1383 /*
1384 * Handle the case where we have a real primary handler and a
1385 * thread handler. We force thread them as well by creating a
1386 * secondary action.
1387 */
1388 if (new->handler && new->thread_fn) {
1389 /* Allocate the secondary action */
1390 new->secondary = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1391 if (!new->secondary)
1392 return -ENOMEM;
1393 new->secondary->handler = irq_forced_secondary_handler;
1394 new->secondary->thread_fn = new->thread_fn;
1395 new->secondary->dev_id = new->dev_id;
1396 new->secondary->irq = new->irq;
1397 new->secondary->name = new->name;
1398 }
1399 /* Deal with the primary handler */
1400 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
1401 new->thread_fn = new->handler;
1402 new->handler = irq_default_primary_handler;
1403 return 0;
1404}
1405
1406static int irq_request_resources(struct irq_desc *desc)
1407{
1408 struct irq_data *d = &desc->irq_data;
1409 struct irq_chip *c = d->chip;
1410
1411 return c->irq_request_resources ? c->irq_request_resources(d) : 0;
1412}
1413
1414static void irq_release_resources(struct irq_desc *desc)
1415{
1416 struct irq_data *d = &desc->irq_data;
1417 struct irq_chip *c = d->chip;
1418
1419 if (c->irq_release_resources)
1420 c->irq_release_resources(d);
1421}
1422
1423static bool irq_supports_nmi(struct irq_desc *desc)
1424{
1425 struct irq_data *d = irq_desc_get_irq_data(desc);
1426
1427#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
1428 /* Only IRQs directly managed by the root irqchip can be set as NMI */
1429 if (d->parent_data)
1430 return false;
1431#endif
1432 /* Don't support NMIs for chips behind a slow bus */
1433 if (d->chip->irq_bus_lock || d->chip->irq_bus_sync_unlock)
1434 return false;
1435
1436 return d->chip->flags & IRQCHIP_SUPPORTS_NMI;
1437}
1438
1439static int irq_nmi_setup(struct irq_desc *desc)
1440{
1441 struct irq_data *d = irq_desc_get_irq_data(desc);
1442 struct irq_chip *c = d->chip;
1443
1444 return c->irq_nmi_setup ? c->irq_nmi_setup(d) : -EINVAL;
1445}
1446
1447static void irq_nmi_teardown(struct irq_desc *desc)
1448{
1449 struct irq_data *d = irq_desc_get_irq_data(desc);
1450 struct irq_chip *c = d->chip;
1451
1452 if (c->irq_nmi_teardown)
1453 c->irq_nmi_teardown(d);
1454}
1455
1456static int
1457setup_irq_thread(struct irqaction *new, unsigned int irq, bool secondary)
1458{
1459 struct task_struct *t;
1460
1461 if (!secondary) {
1462 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
1463 new->name);
1464 } else {
1465 t = kthread_create(irq_thread, new, "irq/%d-s-%s", irq,
1466 new->name);
1467 }
1468
1469 if (IS_ERR(t))
1470 return PTR_ERR(t);
1471
1472 /*
1473 * We keep the reference to the task struct even if
1474 * the thread dies to avoid that the interrupt code
1475 * references an already freed task_struct.
1476 */
1477 new->thread = get_task_struct(t);
1478 /*
1479 * Tell the thread to set its affinity. This is
1480 * important for shared interrupt handlers as we do
1481 * not invoke setup_affinity() for the secondary
1482 * handlers as everything is already set up. Even for
1483 * interrupts marked with IRQF_NO_BALANCE this is
1484 * correct as we want the thread to move to the cpu(s)
1485 * on which the requesting code placed the interrupt.
1486 */
1487 set_bit(IRQTF_AFFINITY, &new->thread_flags);
1488 return 0;
1489}
1490
1491/*
1492 * Internal function to register an irqaction - typically used to
1493 * allocate special interrupts that are part of the architecture.
1494 *
1495 * Locking rules:
1496 *
1497 * desc->request_mutex Provides serialization against a concurrent free_irq()
1498 * chip_bus_lock Provides serialization for slow bus operations
1499 * desc->lock Provides serialization against hard interrupts
1500 *
1501 * chip_bus_lock and desc->lock are sufficient for all other management and
1502 * interrupt related functions. desc->request_mutex solely serializes
1503 * request/free_irq().
1504 */
1505static int
1506__setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
1507{
1508 struct irqaction *old, **old_ptr;
1509 unsigned long flags, thread_mask = 0;
1510 int ret, nested, shared = 0;
1511
1512 if (!desc)
1513 return -EINVAL;
1514
1515 if (desc->irq_data.chip == &no_irq_chip)
1516 return -ENOSYS;
1517 if (!try_module_get(desc->owner))
1518 return -ENODEV;
1519
1520 new->irq = irq;
1521
1522 /*
1523 * If the trigger type is not specified by the caller,
1524 * then use the default for this interrupt.
1525 */
1526 if (!(new->flags & IRQF_TRIGGER_MASK))
1527 new->flags |= irqd_get_trigger_type(&desc->irq_data);
1528
1529 /*
1530 * Check whether the interrupt nests into another interrupt
1531 * thread.
1532 */
1533 nested = irq_settings_is_nested_thread(desc);
1534 if (nested) {
1535 if (!new->thread_fn) {
1536 ret = -EINVAL;
1537 goto out_mput;
1538 }
1539 /*
1540 * Replace the primary handler which was provided from
1541 * the driver for non nested interrupt handling by the
1542 * dummy function which warns when called.
1543 */
1544 new->handler = irq_nested_primary_handler;
1545 } else {
1546 if (irq_settings_can_thread(desc)) {
1547 ret = irq_setup_forced_threading(new);
1548 if (ret)
1549 goto out_mput;
1550 }
1551 }
1552
1553 /*
1554 * Create a handler thread when a thread function is supplied
1555 * and the interrupt does not nest into another interrupt
1556 * thread.
1557 */
1558 if (new->thread_fn && !nested) {
1559 ret = setup_irq_thread(new, irq, false);
1560 if (ret)
1561 goto out_mput;
1562 if (new->secondary) {
1563 ret = setup_irq_thread(new->secondary, irq, true);
1564 if (ret)
1565 goto out_thread;
1566 }
1567 }
1568
1569 /*
1570 * Drivers are often written to work w/o knowledge about the
1571 * underlying irq chip implementation, so a request for a
1572 * threaded irq without a primary hard irq context handler
1573 * requires the ONESHOT flag to be set. Some irq chips like
1574 * MSI based interrupts are per se one shot safe. Check the
1575 * chip flags, so we can avoid the unmask dance at the end of
1576 * the threaded handler for those.
1577 */
1578 if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
1579 new->flags &= ~IRQF_ONESHOT;
1580
1581 /*
1582 * Protects against a concurrent __free_irq() call which might wait
1583 * for synchronize_hardirq() to complete without holding the optional
1584 * chip bus lock and desc->lock. Also protects against handing out
1585 * a recycled oneshot thread_mask bit while it's still in use by
1586 * its previous owner.
1587 */
1588 mutex_lock(&desc->request_mutex);
1589
1590 /*
1591 * Acquire bus lock as the irq_request_resources() callback below
1592 * might rely on the serialization or the magic power management
1593 * functions which are abusing the irq_bus_lock() callback,
1594 */
1595 chip_bus_lock(desc);
1596
1597 /* First installed action requests resources. */
1598 if (!desc->action) {
1599 ret = irq_request_resources(desc);
1600 if (ret) {
1601 pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
1602 new->name, irq, desc->irq_data.chip->name);
1603 goto out_bus_unlock;
1604 }
1605 }
1606
1607 /*
1608 * The following block of code has to be executed atomically
1609 * protected against a concurrent interrupt and any of the other
1610 * management calls which are not serialized via
1611 * desc->request_mutex or the optional bus lock.
1612 */
1613 raw_spin_lock_irqsave(&desc->lock, flags);
1614 old_ptr = &desc->action;
1615 old = *old_ptr;
1616 if (old) {
1617 /*
1618 * Can't share interrupts unless both agree to and are
1619 * the same type (level, edge, polarity). So both flag
1620 * fields must have IRQF_SHARED set and the bits which
1621 * set the trigger type must match. Also all must
1622 * agree on ONESHOT.
1623 * Interrupt lines used for NMIs cannot be shared.
1624 */
1625 unsigned int oldtype;
1626
1627 if (desc->istate & IRQS_NMI) {
1628 pr_err("Invalid attempt to share NMI for %s (irq %d) on irqchip %s.\n",
1629 new->name, irq, desc->irq_data.chip->name);
1630 ret = -EINVAL;
1631 goto out_unlock;
1632 }
1633
1634 /*
1635 * If nobody did set the configuration before, inherit
1636 * the one provided by the requester.
1637 */
1638 if (irqd_trigger_type_was_set(&desc->irq_data)) {
1639 oldtype = irqd_get_trigger_type(&desc->irq_data);
1640 } else {
1641 oldtype = new->flags & IRQF_TRIGGER_MASK;
1642 irqd_set_trigger_type(&desc->irq_data, oldtype);
1643 }
1644
1645 if (!((old->flags & new->flags) & IRQF_SHARED) ||
1646 (oldtype != (new->flags & IRQF_TRIGGER_MASK)))
1647 goto mismatch;
1648
1649 if ((old->flags & IRQF_ONESHOT) &&
1650 (new->flags & IRQF_COND_ONESHOT))
1651 new->flags |= IRQF_ONESHOT;
1652 else if ((old->flags ^ new->flags) & IRQF_ONESHOT)
1653 goto mismatch;
1654
1655 /* All handlers must agree on per-cpuness */
1656 if ((old->flags & IRQF_PERCPU) !=
1657 (new->flags & IRQF_PERCPU))
1658 goto mismatch;
1659
1660 /* add new interrupt at end of irq queue */
1661 do {
1662 /*
1663 * Or all existing action->thread_mask bits,
1664 * so we can find the next zero bit for this
1665 * new action.
1666 */
1667 thread_mask |= old->thread_mask;
1668 old_ptr = &old->next;
1669 old = *old_ptr;
1670 } while (old);
1671 shared = 1;
1672 }
1673
1674 /*
1675 * Setup the thread mask for this irqaction for ONESHOT. For
1676 * !ONESHOT irqs the thread mask is 0 so we can avoid a
1677 * conditional in irq_wake_thread().
1678 */
1679 if (new->flags & IRQF_ONESHOT) {
1680 /*
1681 * Unlikely to have 32 resp 64 irqs sharing one line,
1682 * but who knows.
1683 */
1684 if (thread_mask == ~0UL) {
1685 ret = -EBUSY;
1686 goto out_unlock;
1687 }
1688 /*
1689 * The thread_mask for the action is or'ed to
1690 * desc->thread_active to indicate that the
1691 * IRQF_ONESHOT thread handler has been woken, but not
1692 * yet finished. The bit is cleared when a thread
1693 * completes. When all threads of a shared interrupt
1694 * line have completed desc->threads_active becomes
1695 * zero and the interrupt line is unmasked. See
1696 * handle.c:irq_wake_thread() for further information.
1697 *
1698 * If no thread is woken by primary (hard irq context)
1699 * interrupt handlers, then desc->threads_active is
1700 * also checked for zero to unmask the irq line in the
1701 * affected hard irq flow handlers
1702 * (handle_[fasteoi|level]_irq).
1703 *
1704 * The new action gets the first zero bit of
1705 * thread_mask assigned. See the loop above which or's
1706 * all existing action->thread_mask bits.
1707 */
1708 new->thread_mask = 1UL << ffz(thread_mask);
1709
1710 } else if (new->handler == irq_default_primary_handler &&
1711 !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
1712 /*
1713 * The interrupt was requested with handler = NULL, so
1714 * we use the default primary handler for it. But it
1715 * does not have the oneshot flag set. In combination
1716 * with level interrupts this is deadly, because the
1717 * default primary handler just wakes the thread, then
1718 * the irq lines is reenabled, but the device still
1719 * has the level irq asserted. Rinse and repeat....
1720 *
1721 * While this works for edge type interrupts, we play
1722 * it safe and reject unconditionally because we can't
1723 * say for sure which type this interrupt really
1724 * has. The type flags are unreliable as the
1725 * underlying chip implementation can override them.
1726 */
1727 pr_err("Threaded irq requested with handler=NULL and !ONESHOT for %s (irq %d)\n",
1728 new->name, irq);
1729 ret = -EINVAL;
1730 goto out_unlock;
1731 }
1732
1733 if (!shared) {
1734 /* Setup the type (level, edge polarity) if configured: */
1735 if (new->flags & IRQF_TRIGGER_MASK) {
1736 ret = __irq_set_trigger(desc,
1737 new->flags & IRQF_TRIGGER_MASK);
1738
1739 if (ret)
1740 goto out_unlock;
1741 }
1742
1743 /*
1744 * Activate the interrupt. That activation must happen
1745 * independently of IRQ_NOAUTOEN. request_irq() can fail
1746 * and the callers are supposed to handle
1747 * that. enable_irq() of an interrupt requested with
1748 * IRQ_NOAUTOEN is not supposed to fail. The activation
1749 * keeps it in shutdown mode, it merily associates
1750 * resources if necessary and if that's not possible it
1751 * fails. Interrupts which are in managed shutdown mode
1752 * will simply ignore that activation request.
1753 */
1754 ret = irq_activate(desc);
1755 if (ret)
1756 goto out_unlock;
1757
1758 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1759 IRQS_ONESHOT | IRQS_WAITING);
1760 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1761
1762 if (new->flags & IRQF_PERCPU) {
1763 irqd_set(&desc->irq_data, IRQD_PER_CPU);
1764 irq_settings_set_per_cpu(desc);
1765 if (new->flags & IRQF_NO_DEBUG)
1766 irq_settings_set_no_debug(desc);
1767 }
1768
1769 if (noirqdebug)
1770 irq_settings_set_no_debug(desc);
1771
1772 if (new->flags & IRQF_ONESHOT)
1773 desc->istate |= IRQS_ONESHOT;
1774
1775 /* Exclude IRQ from balancing if requested */
1776 if (new->flags & IRQF_NOBALANCING) {
1777 irq_settings_set_no_balancing(desc);
1778 irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1779 }
1780
1781 if (!(new->flags & IRQF_NO_AUTOEN) &&
1782 irq_settings_can_autoenable(desc)) {
1783 irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
1784 } else {
1785 /*
1786 * Shared interrupts do not go well with disabling
1787 * auto enable. The sharing interrupt might request
1788 * it while it's still disabled and then wait for
1789 * interrupts forever.
1790 */
1791 WARN_ON_ONCE(new->flags & IRQF_SHARED);
1792 /* Undo nested disables: */
1793 desc->depth = 1;
1794 }
1795
1796 } else if (new->flags & IRQF_TRIGGER_MASK) {
1797 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1798 unsigned int omsk = irqd_get_trigger_type(&desc->irq_data);
1799
1800 if (nmsk != omsk)
1801 /* hope the handler works with current trigger mode */
1802 pr_warn("irq %d uses trigger mode %u; requested %u\n",
1803 irq, omsk, nmsk);
1804 }
1805
1806 *old_ptr = new;
1807
1808 irq_pm_install_action(desc, new);
1809
1810 /* Reset broken irq detection when installing new handler */
1811 desc->irq_count = 0;
1812 desc->irqs_unhandled = 0;
1813
1814 /*
1815 * Check whether we disabled the irq via the spurious handler
1816 * before. Reenable it and give it another chance.
1817 */
1818 if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1819 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1820 __enable_irq(desc);
1821 }
1822
1823 raw_spin_unlock_irqrestore(&desc->lock, flags);
1824 chip_bus_sync_unlock(desc);
1825 mutex_unlock(&desc->request_mutex);
1826
1827 irq_setup_timings(desc, new);
1828
1829 wake_up_and_wait_for_irq_thread_ready(desc, new);
1830 wake_up_and_wait_for_irq_thread_ready(desc, new->secondary);
1831
1832 register_irq_proc(irq, desc);
1833 new->dir = NULL;
1834 register_handler_proc(irq, new);
1835 return 0;
1836
1837mismatch:
1838 if (!(new->flags & IRQF_PROBE_SHARED)) {
1839 pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1840 irq, new->flags, new->name, old->flags, old->name);
1841#ifdef CONFIG_DEBUG_SHIRQ
1842 dump_stack();
1843#endif
1844 }
1845 ret = -EBUSY;
1846
1847out_unlock:
1848 raw_spin_unlock_irqrestore(&desc->lock, flags);
1849
1850 if (!desc->action)
1851 irq_release_resources(desc);
1852out_bus_unlock:
1853 chip_bus_sync_unlock(desc);
1854 mutex_unlock(&desc->request_mutex);
1855
1856out_thread:
1857 if (new->thread) {
1858 struct task_struct *t = new->thread;
1859
1860 new->thread = NULL;
1861 kthread_stop_put(t);
1862 }
1863 if (new->secondary && new->secondary->thread) {
1864 struct task_struct *t = new->secondary->thread;
1865
1866 new->secondary->thread = NULL;
1867 kthread_stop_put(t);
1868 }
1869out_mput:
1870 module_put(desc->owner);
1871 return ret;
1872}
1873
1874/*
1875 * Internal function to unregister an irqaction - used to free
1876 * regular and special interrupts that are part of the architecture.
1877 */
1878static struct irqaction *__free_irq(struct irq_desc *desc, void *dev_id)
1879{
1880 unsigned irq = desc->irq_data.irq;
1881 struct irqaction *action, **action_ptr;
1882 unsigned long flags;
1883
1884 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1885
1886 mutex_lock(&desc->request_mutex);
1887 chip_bus_lock(desc);
1888 raw_spin_lock_irqsave(&desc->lock, flags);
1889
1890 /*
1891 * There can be multiple actions per IRQ descriptor, find the right
1892 * one based on the dev_id:
1893 */
1894 action_ptr = &desc->action;
1895 for (;;) {
1896 action = *action_ptr;
1897
1898 if (!action) {
1899 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1900 raw_spin_unlock_irqrestore(&desc->lock, flags);
1901 chip_bus_sync_unlock(desc);
1902 mutex_unlock(&desc->request_mutex);
1903 return NULL;
1904 }
1905
1906 if (action->dev_id == dev_id)
1907 break;
1908 action_ptr = &action->next;
1909 }
1910
1911 /* Found it - now remove it from the list of entries: */
1912 *action_ptr = action->next;
1913
1914 irq_pm_remove_action(desc, action);
1915
1916 /* If this was the last handler, shut down the IRQ line: */
1917 if (!desc->action) {
1918 irq_settings_clr_disable_unlazy(desc);
1919 /* Only shutdown. Deactivate after synchronize_hardirq() */
1920 irq_shutdown(desc);
1921 }
1922
1923#ifdef CONFIG_SMP
1924 /* make sure affinity_hint is cleaned up */
1925 if (WARN_ON_ONCE(desc->affinity_hint))
1926 desc->affinity_hint = NULL;
1927#endif
1928
1929 raw_spin_unlock_irqrestore(&desc->lock, flags);
1930 /*
1931 * Drop bus_lock here so the changes which were done in the chip
1932 * callbacks above are synced out to the irq chips which hang
1933 * behind a slow bus (I2C, SPI) before calling synchronize_hardirq().
1934 *
1935 * Aside of that the bus_lock can also be taken from the threaded
1936 * handler in irq_finalize_oneshot() which results in a deadlock
1937 * because kthread_stop() would wait forever for the thread to
1938 * complete, which is blocked on the bus lock.
1939 *
1940 * The still held desc->request_mutex() protects against a
1941 * concurrent request_irq() of this irq so the release of resources
1942 * and timing data is properly serialized.
1943 */
1944 chip_bus_sync_unlock(desc);
1945
1946 unregister_handler_proc(irq, action);
1947
1948 /*
1949 * Make sure it's not being used on another CPU and if the chip
1950 * supports it also make sure that there is no (not yet serviced)
1951 * interrupt in flight at the hardware level.
1952 */
1953 __synchronize_irq(desc);
1954
1955#ifdef CONFIG_DEBUG_SHIRQ
1956 /*
1957 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1958 * event to happen even now it's being freed, so let's make sure that
1959 * is so by doing an extra call to the handler ....
1960 *
1961 * ( We do this after actually deregistering it, to make sure that a
1962 * 'real' IRQ doesn't run in parallel with our fake. )
1963 */
1964 if (action->flags & IRQF_SHARED) {
1965 local_irq_save(flags);
1966 action->handler(irq, dev_id);
1967 local_irq_restore(flags);
1968 }
1969#endif
1970
1971 /*
1972 * The action has already been removed above, but the thread writes
1973 * its oneshot mask bit when it completes. Though request_mutex is
1974 * held across this which prevents __setup_irq() from handing out
1975 * the same bit to a newly requested action.
1976 */
1977 if (action->thread) {
1978 kthread_stop_put(action->thread);
1979 if (action->secondary && action->secondary->thread)
1980 kthread_stop_put(action->secondary->thread);
1981 }
1982
1983 /* Last action releases resources */
1984 if (!desc->action) {
1985 /*
1986 * Reacquire bus lock as irq_release_resources() might
1987 * require it to deallocate resources over the slow bus.
1988 */
1989 chip_bus_lock(desc);
1990 /*
1991 * There is no interrupt on the fly anymore. Deactivate it
1992 * completely.
1993 */
1994 raw_spin_lock_irqsave(&desc->lock, flags);
1995 irq_domain_deactivate_irq(&desc->irq_data);
1996 raw_spin_unlock_irqrestore(&desc->lock, flags);
1997
1998 irq_release_resources(desc);
1999 chip_bus_sync_unlock(desc);
2000 irq_remove_timings(desc);
2001 }
2002
2003 mutex_unlock(&desc->request_mutex);
2004
2005 irq_chip_pm_put(&desc->irq_data);
2006 module_put(desc->owner);
2007 kfree(action->secondary);
2008 return action;
2009}
2010
2011/**
2012 * free_irq - free an interrupt allocated with request_irq
2013 * @irq: Interrupt line to free
2014 * @dev_id: Device identity to free
2015 *
2016 * Remove an interrupt handler. The handler is removed and if the
2017 * interrupt line is no longer in use by any driver it is disabled.
2018 * On a shared IRQ the caller must ensure the interrupt is disabled
2019 * on the card it drives before calling this function. The function
2020 * does not return until any executing interrupts for this IRQ
2021 * have completed.
2022 *
2023 * This function must not be called from interrupt context.
2024 *
2025 * Returns the devname argument passed to request_irq.
2026 */
2027const void *free_irq(unsigned int irq, void *dev_id)
2028{
2029 struct irq_desc *desc = irq_to_desc(irq);
2030 struct irqaction *action;
2031 const char *devname;
2032
2033 if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
2034 return NULL;
2035
2036#ifdef CONFIG_SMP
2037 if (WARN_ON(desc->affinity_notify))
2038 desc->affinity_notify = NULL;
2039#endif
2040
2041 action = __free_irq(desc, dev_id);
2042
2043 if (!action)
2044 return NULL;
2045
2046 devname = action->name;
2047 kfree(action);
2048 return devname;
2049}
2050EXPORT_SYMBOL(free_irq);
2051
2052/* This function must be called with desc->lock held */
2053static const void *__cleanup_nmi(unsigned int irq, struct irq_desc *desc)
2054{
2055 const char *devname = NULL;
2056
2057 desc->istate &= ~IRQS_NMI;
2058
2059 if (!WARN_ON(desc->action == NULL)) {
2060 irq_pm_remove_action(desc, desc->action);
2061 devname = desc->action->name;
2062 unregister_handler_proc(irq, desc->action);
2063
2064 kfree(desc->action);
2065 desc->action = NULL;
2066 }
2067
2068 irq_settings_clr_disable_unlazy(desc);
2069 irq_shutdown_and_deactivate(desc);
2070
2071 irq_release_resources(desc);
2072
2073 irq_chip_pm_put(&desc->irq_data);
2074 module_put(desc->owner);
2075
2076 return devname;
2077}
2078
2079const void *free_nmi(unsigned int irq, void *dev_id)
2080{
2081 struct irq_desc *desc = irq_to_desc(irq);
2082 unsigned long flags;
2083 const void *devname;
2084
2085 if (!desc || WARN_ON(!(desc->istate & IRQS_NMI)))
2086 return NULL;
2087
2088 if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
2089 return NULL;
2090
2091 /* NMI still enabled */
2092 if (WARN_ON(desc->depth == 0))
2093 disable_nmi_nosync(irq);
2094
2095 raw_spin_lock_irqsave(&desc->lock, flags);
2096
2097 irq_nmi_teardown(desc);
2098 devname = __cleanup_nmi(irq, desc);
2099
2100 raw_spin_unlock_irqrestore(&desc->lock, flags);
2101
2102 return devname;
2103}
2104
2105/**
2106 * request_threaded_irq - allocate an interrupt line
2107 * @irq: Interrupt line to allocate
2108 * @handler: Function to be called when the IRQ occurs.
2109 * Primary handler for threaded interrupts.
2110 * If handler is NULL and thread_fn != NULL
2111 * the default primary handler is installed.
2112 * @thread_fn: Function called from the irq handler thread
2113 * If NULL, no irq thread is created
2114 * @irqflags: Interrupt type flags
2115 * @devname: An ascii name for the claiming device
2116 * @dev_id: A cookie passed back to the handler function
2117 *
2118 * This call allocates interrupt resources and enables the
2119 * interrupt line and IRQ handling. From the point this
2120 * call is made your handler function may be invoked. Since
2121 * your handler function must clear any interrupt the board
2122 * raises, you must take care both to initialise your hardware
2123 * and to set up the interrupt handler in the right order.
2124 *
2125 * If you want to set up a threaded irq handler for your device
2126 * then you need to supply @handler and @thread_fn. @handler is
2127 * still called in hard interrupt context and has to check
2128 * whether the interrupt originates from the device. If yes it
2129 * needs to disable the interrupt on the device and return
2130 * IRQ_WAKE_THREAD which will wake up the handler thread and run
2131 * @thread_fn. This split handler design is necessary to support
2132 * shared interrupts.
2133 *
2134 * Dev_id must be globally unique. Normally the address of the
2135 * device data structure is used as the cookie. Since the handler
2136 * receives this value it makes sense to use it.
2137 *
2138 * If your interrupt is shared you must pass a non NULL dev_id
2139 * as this is required when freeing the interrupt.
2140 *
2141 * Flags:
2142 *
2143 * IRQF_SHARED Interrupt is shared
2144 * IRQF_TRIGGER_* Specify active edge(s) or level
2145 * IRQF_ONESHOT Run thread_fn with interrupt line masked
2146 */
2147int request_threaded_irq(unsigned int irq, irq_handler_t handler,
2148 irq_handler_t thread_fn, unsigned long irqflags,
2149 const char *devname, void *dev_id)
2150{
2151 struct irqaction *action;
2152 struct irq_desc *desc;
2153 int retval;
2154
2155 if (irq == IRQ_NOTCONNECTED)
2156 return -ENOTCONN;
2157
2158 /*
2159 * Sanity-check: shared interrupts must pass in a real dev-ID,
2160 * otherwise we'll have trouble later trying to figure out
2161 * which interrupt is which (messes up the interrupt freeing
2162 * logic etc).
2163 *
2164 * Also shared interrupts do not go well with disabling auto enable.
2165 * The sharing interrupt might request it while it's still disabled
2166 * and then wait for interrupts forever.
2167 *
2168 * Also IRQF_COND_SUSPEND only makes sense for shared interrupts and
2169 * it cannot be set along with IRQF_NO_SUSPEND.
2170 */
2171 if (((irqflags & IRQF_SHARED) && !dev_id) ||
2172 ((irqflags & IRQF_SHARED) && (irqflags & IRQF_NO_AUTOEN)) ||
2173 (!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) ||
2174 ((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND)))
2175 return -EINVAL;
2176
2177 desc = irq_to_desc(irq);
2178 if (!desc)
2179 return -EINVAL;
2180
2181 if (!irq_settings_can_request(desc) ||
2182 WARN_ON(irq_settings_is_per_cpu_devid(desc)))
2183 return -EINVAL;
2184
2185 if (!handler) {
2186 if (!thread_fn)
2187 return -EINVAL;
2188 handler = irq_default_primary_handler;
2189 }
2190
2191 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
2192 if (!action)
2193 return -ENOMEM;
2194
2195 action->handler = handler;
2196 action->thread_fn = thread_fn;
2197 action->flags = irqflags;
2198 action->name = devname;
2199 action->dev_id = dev_id;
2200
2201 retval = irq_chip_pm_get(&desc->irq_data);
2202 if (retval < 0) {
2203 kfree(action);
2204 return retval;
2205 }
2206
2207 retval = __setup_irq(irq, desc, action);
2208
2209 if (retval) {
2210 irq_chip_pm_put(&desc->irq_data);
2211 kfree(action->secondary);
2212 kfree(action);
2213 }
2214
2215#ifdef CONFIG_DEBUG_SHIRQ_FIXME
2216 if (!retval && (irqflags & IRQF_SHARED)) {
2217 /*
2218 * It's a shared IRQ -- the driver ought to be prepared for it
2219 * to happen immediately, so let's make sure....
2220 * We disable the irq to make sure that a 'real' IRQ doesn't
2221 * run in parallel with our fake.
2222 */
2223 unsigned long flags;
2224
2225 disable_irq(irq);
2226 local_irq_save(flags);
2227
2228 handler(irq, dev_id);
2229
2230 local_irq_restore(flags);
2231 enable_irq(irq);
2232 }
2233#endif
2234 return retval;
2235}
2236EXPORT_SYMBOL(request_threaded_irq);
2237
2238/**
2239 * request_any_context_irq - allocate an interrupt line
2240 * @irq: Interrupt line to allocate
2241 * @handler: Function to be called when the IRQ occurs.
2242 * Threaded handler for threaded interrupts.
2243 * @flags: Interrupt type flags
2244 * @name: An ascii name for the claiming device
2245 * @dev_id: A cookie passed back to the handler function
2246 *
2247 * This call allocates interrupt resources and enables the
2248 * interrupt line and IRQ handling. It selects either a
2249 * hardirq or threaded handling method depending on the
2250 * context.
2251 *
2252 * On failure, it returns a negative value. On success,
2253 * it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
2254 */
2255int request_any_context_irq(unsigned int irq, irq_handler_t handler,
2256 unsigned long flags, const char *name, void *dev_id)
2257{
2258 struct irq_desc *desc;
2259 int ret;
2260
2261 if (irq == IRQ_NOTCONNECTED)
2262 return -ENOTCONN;
2263
2264 desc = irq_to_desc(irq);
2265 if (!desc)
2266 return -EINVAL;
2267
2268 if (irq_settings_is_nested_thread(desc)) {
2269 ret = request_threaded_irq(irq, NULL, handler,
2270 flags, name, dev_id);
2271 return !ret ? IRQC_IS_NESTED : ret;
2272 }
2273
2274 ret = request_irq(irq, handler, flags, name, dev_id);
2275 return !ret ? IRQC_IS_HARDIRQ : ret;
2276}
2277EXPORT_SYMBOL_GPL(request_any_context_irq);
2278
2279/**
2280 * request_nmi - allocate an interrupt line for NMI delivery
2281 * @irq: Interrupt line to allocate
2282 * @handler: Function to be called when the IRQ occurs.
2283 * Threaded handler for threaded interrupts.
2284 * @irqflags: Interrupt type flags
2285 * @name: An ascii name for the claiming device
2286 * @dev_id: A cookie passed back to the handler function
2287 *
2288 * This call allocates interrupt resources and enables the
2289 * interrupt line and IRQ handling. It sets up the IRQ line
2290 * to be handled as an NMI.
2291 *
2292 * An interrupt line delivering NMIs cannot be shared and IRQ handling
2293 * cannot be threaded.
2294 *
2295 * Interrupt lines requested for NMI delivering must produce per cpu
2296 * interrupts and have auto enabling setting disabled.
2297 *
2298 * Dev_id must be globally unique. Normally the address of the
2299 * device data structure is used as the cookie. Since the handler
2300 * receives this value it makes sense to use it.
2301 *
2302 * If the interrupt line cannot be used to deliver NMIs, function
2303 * will fail and return a negative value.
2304 */
2305int request_nmi(unsigned int irq, irq_handler_t handler,
2306 unsigned long irqflags, const char *name, void *dev_id)
2307{
2308 struct irqaction *action;
2309 struct irq_desc *desc;
2310 unsigned long flags;
2311 int retval;
2312
2313 if (irq == IRQ_NOTCONNECTED)
2314 return -ENOTCONN;
2315
2316 /* NMI cannot be shared, used for Polling */
2317 if (irqflags & (IRQF_SHARED | IRQF_COND_SUSPEND | IRQF_IRQPOLL))
2318 return -EINVAL;
2319
2320 if (!(irqflags & IRQF_PERCPU))
2321 return -EINVAL;
2322
2323 if (!handler)
2324 return -EINVAL;
2325
2326 desc = irq_to_desc(irq);
2327
2328 if (!desc || (irq_settings_can_autoenable(desc) &&
2329 !(irqflags & IRQF_NO_AUTOEN)) ||
2330 !irq_settings_can_request(desc) ||
2331 WARN_ON(irq_settings_is_per_cpu_devid(desc)) ||
2332 !irq_supports_nmi(desc))
2333 return -EINVAL;
2334
2335 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
2336 if (!action)
2337 return -ENOMEM;
2338
2339 action->handler = handler;
2340 action->flags = irqflags | IRQF_NO_THREAD | IRQF_NOBALANCING;
2341 action->name = name;
2342 action->dev_id = dev_id;
2343
2344 retval = irq_chip_pm_get(&desc->irq_data);
2345 if (retval < 0)
2346 goto err_out;
2347
2348 retval = __setup_irq(irq, desc, action);
2349 if (retval)
2350 goto err_irq_setup;
2351
2352 raw_spin_lock_irqsave(&desc->lock, flags);
2353
2354 /* Setup NMI state */
2355 desc->istate |= IRQS_NMI;
2356 retval = irq_nmi_setup(desc);
2357 if (retval) {
2358 __cleanup_nmi(irq, desc);
2359 raw_spin_unlock_irqrestore(&desc->lock, flags);
2360 return -EINVAL;
2361 }
2362
2363 raw_spin_unlock_irqrestore(&desc->lock, flags);
2364
2365 return 0;
2366
2367err_irq_setup:
2368 irq_chip_pm_put(&desc->irq_data);
2369err_out:
2370 kfree(action);
2371
2372 return retval;
2373}
2374
2375void enable_percpu_irq(unsigned int irq, unsigned int type)
2376{
2377 unsigned int cpu = smp_processor_id();
2378 unsigned long flags;
2379 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
2380
2381 if (!desc)
2382 return;
2383
2384 /*
2385 * If the trigger type is not specified by the caller, then
2386 * use the default for this interrupt.
2387 */
2388 type &= IRQ_TYPE_SENSE_MASK;
2389 if (type == IRQ_TYPE_NONE)
2390 type = irqd_get_trigger_type(&desc->irq_data);
2391
2392 if (type != IRQ_TYPE_NONE) {
2393 int ret;
2394
2395 ret = __irq_set_trigger(desc, type);
2396
2397 if (ret) {
2398 WARN(1, "failed to set type for IRQ%d\n", irq);
2399 goto out;
2400 }
2401 }
2402
2403 irq_percpu_enable(desc, cpu);
2404out:
2405 irq_put_desc_unlock(desc, flags);
2406}
2407EXPORT_SYMBOL_GPL(enable_percpu_irq);
2408
2409void enable_percpu_nmi(unsigned int irq, unsigned int type)
2410{
2411 enable_percpu_irq(irq, type);
2412}
2413
2414/**
2415 * irq_percpu_is_enabled - Check whether the per cpu irq is enabled
2416 * @irq: Linux irq number to check for
2417 *
2418 * Must be called from a non migratable context. Returns the enable
2419 * state of a per cpu interrupt on the current cpu.
2420 */
2421bool irq_percpu_is_enabled(unsigned int irq)
2422{
2423 unsigned int cpu = smp_processor_id();
2424 struct irq_desc *desc;
2425 unsigned long flags;
2426 bool is_enabled;
2427
2428 desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
2429 if (!desc)
2430 return false;
2431
2432 is_enabled = cpumask_test_cpu(cpu, desc->percpu_enabled);
2433 irq_put_desc_unlock(desc, flags);
2434
2435 return is_enabled;
2436}
2437EXPORT_SYMBOL_GPL(irq_percpu_is_enabled);
2438
2439void disable_percpu_irq(unsigned int irq)
2440{
2441 unsigned int cpu = smp_processor_id();
2442 unsigned long flags;
2443 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
2444
2445 if (!desc)
2446 return;
2447
2448 irq_percpu_disable(desc, cpu);
2449 irq_put_desc_unlock(desc, flags);
2450}
2451EXPORT_SYMBOL_GPL(disable_percpu_irq);
2452
2453void disable_percpu_nmi(unsigned int irq)
2454{
2455 disable_percpu_irq(irq);
2456}
2457
2458/*
2459 * Internal function to unregister a percpu irqaction.
2460 */
2461static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
2462{
2463 struct irq_desc *desc = irq_to_desc(irq);
2464 struct irqaction *action;
2465 unsigned long flags;
2466
2467 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
2468
2469 if (!desc)
2470 return NULL;
2471
2472 raw_spin_lock_irqsave(&desc->lock, flags);
2473
2474 action = desc->action;
2475 if (!action || action->percpu_dev_id != dev_id) {
2476 WARN(1, "Trying to free already-free IRQ %d\n", irq);
2477 goto bad;
2478 }
2479
2480 if (!cpumask_empty(desc->percpu_enabled)) {
2481 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
2482 irq, cpumask_first(desc->percpu_enabled));
2483 goto bad;
2484 }
2485
2486 /* Found it - now remove it from the list of entries: */
2487 desc->action = NULL;
2488
2489 desc->istate &= ~IRQS_NMI;
2490
2491 raw_spin_unlock_irqrestore(&desc->lock, flags);
2492
2493 unregister_handler_proc(irq, action);
2494
2495 irq_chip_pm_put(&desc->irq_data);
2496 module_put(desc->owner);
2497 return action;
2498
2499bad:
2500 raw_spin_unlock_irqrestore(&desc->lock, flags);
2501 return NULL;
2502}
2503
2504/**
2505 * remove_percpu_irq - free a per-cpu interrupt
2506 * @irq: Interrupt line to free
2507 * @act: irqaction for the interrupt
2508 *
2509 * Used to remove interrupts statically setup by the early boot process.
2510 */
2511void remove_percpu_irq(unsigned int irq, struct irqaction *act)
2512{
2513 struct irq_desc *desc = irq_to_desc(irq);
2514
2515 if (desc && irq_settings_is_per_cpu_devid(desc))
2516 __free_percpu_irq(irq, act->percpu_dev_id);
2517}
2518
2519/**
2520 * free_percpu_irq - free an interrupt allocated with request_percpu_irq
2521 * @irq: Interrupt line to free
2522 * @dev_id: Device identity to free
2523 *
2524 * Remove a percpu interrupt handler. The handler is removed, but
2525 * the interrupt line is not disabled. This must be done on each
2526 * CPU before calling this function. The function does not return
2527 * until any executing interrupts for this IRQ have completed.
2528 *
2529 * This function must not be called from interrupt context.
2530 */
2531void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
2532{
2533 struct irq_desc *desc = irq_to_desc(irq);
2534
2535 if (!desc || !irq_settings_is_per_cpu_devid(desc))
2536 return;
2537
2538 chip_bus_lock(desc);
2539 kfree(__free_percpu_irq(irq, dev_id));
2540 chip_bus_sync_unlock(desc);
2541}
2542EXPORT_SYMBOL_GPL(free_percpu_irq);
2543
2544void free_percpu_nmi(unsigned int irq, void __percpu *dev_id)
2545{
2546 struct irq_desc *desc = irq_to_desc(irq);
2547
2548 if (!desc || !irq_settings_is_per_cpu_devid(desc))
2549 return;
2550
2551 if (WARN_ON(!(desc->istate & IRQS_NMI)))
2552 return;
2553
2554 kfree(__free_percpu_irq(irq, dev_id));
2555}
2556
2557/**
2558 * setup_percpu_irq - setup a per-cpu interrupt
2559 * @irq: Interrupt line to setup
2560 * @act: irqaction for the interrupt
2561 *
2562 * Used to statically setup per-cpu interrupts in the early boot process.
2563 */
2564int setup_percpu_irq(unsigned int irq, struct irqaction *act)
2565{
2566 struct irq_desc *desc = irq_to_desc(irq);
2567 int retval;
2568
2569 if (!desc || !irq_settings_is_per_cpu_devid(desc))
2570 return -EINVAL;
2571
2572 retval = irq_chip_pm_get(&desc->irq_data);
2573 if (retval < 0)
2574 return retval;
2575
2576 retval = __setup_irq(irq, desc, act);
2577
2578 if (retval)
2579 irq_chip_pm_put(&desc->irq_data);
2580
2581 return retval;
2582}
2583
2584/**
2585 * __request_percpu_irq - allocate a percpu interrupt line
2586 * @irq: Interrupt line to allocate
2587 * @handler: Function to be called when the IRQ occurs.
2588 * @flags: Interrupt type flags (IRQF_TIMER only)
2589 * @devname: An ascii name for the claiming device
2590 * @dev_id: A percpu cookie passed back to the handler function
2591 *
2592 * This call allocates interrupt resources and enables the
2593 * interrupt on the local CPU. If the interrupt is supposed to be
2594 * enabled on other CPUs, it has to be done on each CPU using
2595 * enable_percpu_irq().
2596 *
2597 * Dev_id must be globally unique. It is a per-cpu variable, and
2598 * the handler gets called with the interrupted CPU's instance of
2599 * that variable.
2600 */
2601int __request_percpu_irq(unsigned int irq, irq_handler_t handler,
2602 unsigned long flags, const char *devname,
2603 void __percpu *dev_id)
2604{
2605 struct irqaction *action;
2606 struct irq_desc *desc;
2607 int retval;
2608
2609 if (!dev_id)
2610 return -EINVAL;
2611
2612 desc = irq_to_desc(irq);
2613 if (!desc || !irq_settings_can_request(desc) ||
2614 !irq_settings_is_per_cpu_devid(desc))
2615 return -EINVAL;
2616
2617 if (flags && flags != IRQF_TIMER)
2618 return -EINVAL;
2619
2620 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
2621 if (!action)
2622 return -ENOMEM;
2623
2624 action->handler = handler;
2625 action->flags = flags | IRQF_PERCPU | IRQF_NO_SUSPEND;
2626 action->name = devname;
2627 action->percpu_dev_id = dev_id;
2628
2629 retval = irq_chip_pm_get(&desc->irq_data);
2630 if (retval < 0) {
2631 kfree(action);
2632 return retval;
2633 }
2634
2635 retval = __setup_irq(irq, desc, action);
2636
2637 if (retval) {
2638 irq_chip_pm_put(&desc->irq_data);
2639 kfree(action);
2640 }
2641
2642 return retval;
2643}
2644EXPORT_SYMBOL_GPL(__request_percpu_irq);
2645
2646/**
2647 * request_percpu_nmi - allocate a percpu interrupt line for NMI delivery
2648 * @irq: Interrupt line to allocate
2649 * @handler: Function to be called when the IRQ occurs.
2650 * @name: An ascii name for the claiming device
2651 * @dev_id: A percpu cookie passed back to the handler function
2652 *
2653 * This call allocates interrupt resources for a per CPU NMI. Per CPU NMIs
2654 * have to be setup on each CPU by calling prepare_percpu_nmi() before
2655 * being enabled on the same CPU by using enable_percpu_nmi().
2656 *
2657 * Dev_id must be globally unique. It is a per-cpu variable, and
2658 * the handler gets called with the interrupted CPU's instance of
2659 * that variable.
2660 *
2661 * Interrupt lines requested for NMI delivering should have auto enabling
2662 * setting disabled.
2663 *
2664 * If the interrupt line cannot be used to deliver NMIs, function
2665 * will fail returning a negative value.
2666 */
2667int request_percpu_nmi(unsigned int irq, irq_handler_t handler,
2668 const char *name, void __percpu *dev_id)
2669{
2670 struct irqaction *action;
2671 struct irq_desc *desc;
2672 unsigned long flags;
2673 int retval;
2674
2675 if (!handler)
2676 return -EINVAL;
2677
2678 desc = irq_to_desc(irq);
2679
2680 if (!desc || !irq_settings_can_request(desc) ||
2681 !irq_settings_is_per_cpu_devid(desc) ||
2682 irq_settings_can_autoenable(desc) ||
2683 !irq_supports_nmi(desc))
2684 return -EINVAL;
2685
2686 /* The line cannot already be NMI */
2687 if (desc->istate & IRQS_NMI)
2688 return -EINVAL;
2689
2690 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
2691 if (!action)
2692 return -ENOMEM;
2693
2694 action->handler = handler;
2695 action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND | IRQF_NO_THREAD
2696 | IRQF_NOBALANCING;
2697 action->name = name;
2698 action->percpu_dev_id = dev_id;
2699
2700 retval = irq_chip_pm_get(&desc->irq_data);
2701 if (retval < 0)
2702 goto err_out;
2703
2704 retval = __setup_irq(irq, desc, action);
2705 if (retval)
2706 goto err_irq_setup;
2707
2708 raw_spin_lock_irqsave(&desc->lock, flags);
2709 desc->istate |= IRQS_NMI;
2710 raw_spin_unlock_irqrestore(&desc->lock, flags);
2711
2712 return 0;
2713
2714err_irq_setup:
2715 irq_chip_pm_put(&desc->irq_data);
2716err_out:
2717 kfree(action);
2718
2719 return retval;
2720}
2721
2722/**
2723 * prepare_percpu_nmi - performs CPU local setup for NMI delivery
2724 * @irq: Interrupt line to prepare for NMI delivery
2725 *
2726 * This call prepares an interrupt line to deliver NMI on the current CPU,
2727 * before that interrupt line gets enabled with enable_percpu_nmi().
2728 *
2729 * As a CPU local operation, this should be called from non-preemptible
2730 * context.
2731 *
2732 * If the interrupt line cannot be used to deliver NMIs, function
2733 * will fail returning a negative value.
2734 */
2735int prepare_percpu_nmi(unsigned int irq)
2736{
2737 unsigned long flags;
2738 struct irq_desc *desc;
2739 int ret = 0;
2740
2741 WARN_ON(preemptible());
2742
2743 desc = irq_get_desc_lock(irq, &flags,
2744 IRQ_GET_DESC_CHECK_PERCPU);
2745 if (!desc)
2746 return -EINVAL;
2747
2748 if (WARN(!(desc->istate & IRQS_NMI),
2749 KERN_ERR "prepare_percpu_nmi called for a non-NMI interrupt: irq %u\n",
2750 irq)) {
2751 ret = -EINVAL;
2752 goto out;
2753 }
2754
2755 ret = irq_nmi_setup(desc);
2756 if (ret) {
2757 pr_err("Failed to setup NMI delivery: irq %u\n", irq);
2758 goto out;
2759 }
2760
2761out:
2762 irq_put_desc_unlock(desc, flags);
2763 return ret;
2764}
2765
2766/**
2767 * teardown_percpu_nmi - undoes NMI setup of IRQ line
2768 * @irq: Interrupt line from which CPU local NMI configuration should be
2769 * removed
2770 *
2771 * This call undoes the setup done by prepare_percpu_nmi().
2772 *
2773 * IRQ line should not be enabled for the current CPU.
2774 *
2775 * As a CPU local operation, this should be called from non-preemptible
2776 * context.
2777 */
2778void teardown_percpu_nmi(unsigned int irq)
2779{
2780 unsigned long flags;
2781 struct irq_desc *desc;
2782
2783 WARN_ON(preemptible());
2784
2785 desc = irq_get_desc_lock(irq, &flags,
2786 IRQ_GET_DESC_CHECK_PERCPU);
2787 if (!desc)
2788 return;
2789
2790 if (WARN_ON(!(desc->istate & IRQS_NMI)))
2791 goto out;
2792
2793 irq_nmi_teardown(desc);
2794out:
2795 irq_put_desc_unlock(desc, flags);
2796}
2797
2798int __irq_get_irqchip_state(struct irq_data *data, enum irqchip_irq_state which,
2799 bool *state)
2800{
2801 struct irq_chip *chip;
2802 int err = -EINVAL;
2803
2804 do {
2805 chip = irq_data_get_irq_chip(data);
2806 if (WARN_ON_ONCE(!chip))
2807 return -ENODEV;
2808 if (chip->irq_get_irqchip_state)
2809 break;
2810#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
2811 data = data->parent_data;
2812#else
2813 data = NULL;
2814#endif
2815 } while (data);
2816
2817 if (data)
2818 err = chip->irq_get_irqchip_state(data, which, state);
2819 return err;
2820}
2821
2822/**
2823 * irq_get_irqchip_state - returns the irqchip state of a interrupt.
2824 * @irq: Interrupt line that is forwarded to a VM
2825 * @which: One of IRQCHIP_STATE_* the caller wants to know about
2826 * @state: a pointer to a boolean where the state is to be stored
2827 *
2828 * This call snapshots the internal irqchip state of an
2829 * interrupt, returning into @state the bit corresponding to
2830 * stage @which
2831 *
2832 * This function should be called with preemption disabled if the
2833 * interrupt controller has per-cpu registers.
2834 */
2835int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
2836 bool *state)
2837{
2838 struct irq_desc *desc;
2839 struct irq_data *data;
2840 unsigned long flags;
2841 int err = -EINVAL;
2842
2843 desc = irq_get_desc_buslock(irq, &flags, 0);
2844 if (!desc)
2845 return err;
2846
2847 data = irq_desc_get_irq_data(desc);
2848
2849 err = __irq_get_irqchip_state(data, which, state);
2850
2851 irq_put_desc_busunlock(desc, flags);
2852 return err;
2853}
2854EXPORT_SYMBOL_GPL(irq_get_irqchip_state);
2855
2856/**
2857 * irq_set_irqchip_state - set the state of a forwarded interrupt.
2858 * @irq: Interrupt line that is forwarded to a VM
2859 * @which: State to be restored (one of IRQCHIP_STATE_*)
2860 * @val: Value corresponding to @which
2861 *
2862 * This call sets the internal irqchip state of an interrupt,
2863 * depending on the value of @which.
2864 *
2865 * This function should be called with migration disabled if the
2866 * interrupt controller has per-cpu registers.
2867 */
2868int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
2869 bool val)
2870{
2871 struct irq_desc *desc;
2872 struct irq_data *data;
2873 struct irq_chip *chip;
2874 unsigned long flags;
2875 int err = -EINVAL;
2876
2877 desc = irq_get_desc_buslock(irq, &flags, 0);
2878 if (!desc)
2879 return err;
2880
2881 data = irq_desc_get_irq_data(desc);
2882
2883 do {
2884 chip = irq_data_get_irq_chip(data);
2885 if (WARN_ON_ONCE(!chip)) {
2886 err = -ENODEV;
2887 goto out_unlock;
2888 }
2889 if (chip->irq_set_irqchip_state)
2890 break;
2891#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
2892 data = data->parent_data;
2893#else
2894 data = NULL;
2895#endif
2896 } while (data);
2897
2898 if (data)
2899 err = chip->irq_set_irqchip_state(data, which, val);
2900
2901out_unlock:
2902 irq_put_desc_busunlock(desc, flags);
2903 return err;
2904}
2905EXPORT_SYMBOL_GPL(irq_set_irqchip_state);
2906
2907/**
2908 * irq_has_action - Check whether an interrupt is requested
2909 * @irq: The linux irq number
2910 *
2911 * Returns: A snapshot of the current state
2912 */
2913bool irq_has_action(unsigned int irq)
2914{
2915 bool res;
2916
2917 rcu_read_lock();
2918 res = irq_desc_has_action(irq_to_desc(irq));
2919 rcu_read_unlock();
2920 return res;
2921}
2922EXPORT_SYMBOL_GPL(irq_has_action);
2923
2924/**
2925 * irq_check_status_bit - Check whether bits in the irq descriptor status are set
2926 * @irq: The linux irq number
2927 * @bitmask: The bitmask to evaluate
2928 *
2929 * Returns: True if one of the bits in @bitmask is set
2930 */
2931bool irq_check_status_bit(unsigned int irq, unsigned int bitmask)
2932{
2933 struct irq_desc *desc;
2934 bool res = false;
2935
2936 rcu_read_lock();
2937 desc = irq_to_desc(irq);
2938 if (desc)
2939 res = !!(desc->status_use_accessors & bitmask);
2940 rcu_read_unlock();
2941 return res;
2942}
2943EXPORT_SYMBOL_GPL(irq_check_status_bit);
1/*
2 * linux/kernel/irq/manage.c
3 *
4 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
5 * Copyright (C) 2005-2006 Thomas Gleixner
6 *
7 * This file contains driver APIs to the irq subsystem.
8 */
9
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>
17
18#include "internals.h"
19
20#ifdef CONFIG_IRQ_FORCED_THREADING
21__read_mostly bool force_irqthreads;
22
23static int __init setup_forced_irqthreads(char *arg)
24{
25 force_irqthreads = true;
26 return 0;
27}
28early_param("threadirqs", setup_forced_irqthreads);
29#endif
30
31/**
32 * synchronize_irq - wait for pending IRQ handlers (on other CPUs)
33 * @irq: interrupt number to wait for
34 *
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.
38 *
39 * This function may be called - with care - from IRQ context.
40 */
41void synchronize_irq(unsigned int irq)
42{
43 struct irq_desc *desc = irq_to_desc(irq);
44 bool inprogress;
45
46 if (!desc)
47 return;
48
49 do {
50 unsigned long flags;
51
52 /*
53 * Wait until we're out of the critical section. This might
54 * give the wrong answer due to the lack of memory barriers.
55 */
56 while (irqd_irq_inprogress(&desc->irq_data))
57 cpu_relax();
58
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);
63
64 /* Oops, that failed? */
65 } while (inprogress);
66
67 /*
68 * We made sure that no hardirq handler is running. Now verify
69 * that no threaded handlers are active.
70 */
71 wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
72}
73EXPORT_SYMBOL(synchronize_irq);
74
75#ifdef CONFIG_SMP
76cpumask_var_t irq_default_affinity;
77
78/**
79 * irq_can_set_affinity - Check if the affinity of a given irq can be set
80 * @irq: Interrupt to check
81 *
82 */
83int irq_can_set_affinity(unsigned int irq)
84{
85 struct irq_desc *desc = irq_to_desc(irq);
86
87 if (!desc || !irqd_can_balance(&desc->irq_data) ||
88 !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
89 return 0;
90
91 return 1;
92}
93
94/**
95 * irq_set_thread_affinity - Notify irq threads to adjust affinity
96 * @desc: irq descriptor which has affitnity changed
97 *
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.
102 */
103void irq_set_thread_affinity(struct irq_desc *desc)
104{
105 struct irqaction *action = desc->action;
106
107 while (action) {
108 if (action->thread)
109 set_bit(IRQTF_AFFINITY, &action->thread_flags);
110 action = action->next;
111 }
112}
113
114#ifdef CONFIG_GENERIC_PENDING_IRQ
115static inline bool irq_can_move_pcntxt(struct irq_data *data)
116{
117 return irqd_can_move_in_process_context(data);
118}
119static inline bool irq_move_pending(struct irq_data *data)
120{
121 return irqd_is_setaffinity_pending(data);
122}
123static inline void
124irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
125{
126 cpumask_copy(desc->pending_mask, mask);
127}
128static inline void
129irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
130{
131 cpumask_copy(mask, desc->pending_mask);
132}
133#else
134static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
135static inline bool irq_move_pending(struct irq_data *data) { return false; }
136static inline void
137irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
138static inline void
139irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
140#endif
141
142int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask)
143{
144 struct irq_chip *chip = irq_data_get_irq_chip(data);
145 struct irq_desc *desc = irq_data_to_desc(data);
146 int ret = 0;
147
148 if (!chip || !chip->irq_set_affinity)
149 return -EINVAL;
150
151 if (irq_can_move_pcntxt(data)) {
152 ret = chip->irq_set_affinity(data, mask, false);
153 switch (ret) {
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);
158 ret = 0;
159 }
160 } else {
161 irqd_set_move_pending(data);
162 irq_copy_pending(desc, mask);
163 }
164
165 if (desc->affinity_notify) {
166 kref_get(&desc->affinity_notify->kref);
167 schedule_work(&desc->affinity_notify->work);
168 }
169 irqd_set(data, IRQD_AFFINITY_SET);
170
171 return ret;
172}
173
174/**
175 * irq_set_affinity - Set the irq affinity of a given irq
176 * @irq: Interrupt to set affinity
177 * @mask: cpumask
178 *
179 */
180int irq_set_affinity(unsigned int irq, const struct cpumask *mask)
181{
182 struct irq_desc *desc = irq_to_desc(irq);
183 unsigned long flags;
184 int ret;
185
186 if (!desc)
187 return -EINVAL;
188
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);
192 return ret;
193}
194
195int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
196{
197 unsigned long flags;
198 struct irq_desc *desc = irq_get_desc_lock(irq, &flags);
199
200 if (!desc)
201 return -EINVAL;
202 desc->affinity_hint = m;
203 irq_put_desc_unlock(desc, flags);
204 return 0;
205}
206EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
207
208static void irq_affinity_notify(struct work_struct *work)
209{
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;
214 unsigned long flags;
215
216 if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
217 goto out;
218
219 raw_spin_lock_irqsave(&desc->lock, flags);
220 if (irq_move_pending(&desc->irq_data))
221 irq_get_pending(cpumask, desc);
222 else
223 cpumask_copy(cpumask, desc->irq_data.affinity);
224 raw_spin_unlock_irqrestore(&desc->lock, flags);
225
226 notify->notify(notify, cpumask);
227
228 free_cpumask_var(cpumask);
229out:
230 kref_put(¬ify->kref, notify->release);
231}
232
233/**
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.
239 *
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().
243 */
244int
245irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
246{
247 struct irq_desc *desc = irq_to_desc(irq);
248 struct irq_affinity_notify *old_notify;
249 unsigned long flags;
250
251 /* The release function is promised process context */
252 might_sleep();
253
254 if (!desc)
255 return -EINVAL;
256
257 /* Complete initialisation of *notify */
258 if (notify) {
259 notify->irq = irq;
260 kref_init(¬ify->kref);
261 INIT_WORK(¬ify->work, irq_affinity_notify);
262 }
263
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);
268
269 if (old_notify)
270 kref_put(&old_notify->kref, old_notify->release);
271
272 return 0;
273}
274EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
275
276#ifndef CONFIG_AUTO_IRQ_AFFINITY
277/*
278 * Generic version of the affinity autoselector.
279 */
280static int
281setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
282{
283 struct irq_chip *chip = irq_desc_get_chip(desc);
284 struct cpumask *set = irq_default_affinity;
285 int ret;
286
287 /* Excludes PER_CPU and NO_BALANCE interrupts */
288 if (!irq_can_set_affinity(irq))
289 return 0;
290
291 /*
292 * Preserve an userspace affinity setup, but make sure that
293 * one of the targets is online.
294 */
295 if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
296 if (cpumask_intersects(desc->irq_data.affinity,
297 cpu_online_mask))
298 set = desc->irq_data.affinity;
299 else
300 irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
301 }
302
303 cpumask_and(mask, cpu_online_mask, set);
304 ret = chip->irq_set_affinity(&desc->irq_data, mask, false);
305 switch (ret) {
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);
310 }
311 return 0;
312}
313#else
314static inline int
315setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
316{
317 return irq_select_affinity(irq);
318}
319#endif
320
321/*
322 * Called when affinity is set via /proc/irq
323 */
324int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
325{
326 struct irq_desc *desc = irq_to_desc(irq);
327 unsigned long flags;
328 int ret;
329
330 raw_spin_lock_irqsave(&desc->lock, flags);
331 ret = setup_affinity(irq, desc, mask);
332 raw_spin_unlock_irqrestore(&desc->lock, flags);
333 return ret;
334}
335
336#else
337static inline int
338setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
339{
340 return 0;
341}
342#endif
343
344void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
345{
346 if (suspend) {
347 if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
348 return;
349 desc->istate |= IRQS_SUSPENDED;
350 }
351
352 if (!desc->depth++)
353 irq_disable(desc);
354}
355
356static int __disable_irq_nosync(unsigned int irq)
357{
358 unsigned long flags;
359 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags);
360
361 if (!desc)
362 return -EINVAL;
363 __disable_irq(desc, irq, false);
364 irq_put_desc_busunlock(desc, flags);
365 return 0;
366}
367
368/**
369 * disable_irq_nosync - disable an irq without waiting
370 * @irq: Interrupt to disable
371 *
372 * Disable the selected interrupt line. Disables and Enables are
373 * nested.
374 * Unlike disable_irq(), this function does not ensure existing
375 * instances of the IRQ handler have completed before returning.
376 *
377 * This function may be called from IRQ context.
378 */
379void disable_irq_nosync(unsigned int irq)
380{
381 __disable_irq_nosync(irq);
382}
383EXPORT_SYMBOL(disable_irq_nosync);
384
385/**
386 * disable_irq - disable an irq and wait for completion
387 * @irq: Interrupt to disable
388 *
389 * Disable the selected interrupt line. Enables and Disables are
390 * nested.
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.
394 *
395 * This function may be called - with care - from IRQ context.
396 */
397void disable_irq(unsigned int irq)
398{
399 if (!__disable_irq_nosync(irq))
400 synchronize_irq(irq);
401}
402EXPORT_SYMBOL(disable_irq);
403
404void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
405{
406 if (resume) {
407 if (!(desc->istate & IRQS_SUSPENDED)) {
408 if (!desc->action)
409 return;
410 if (!(desc->action->flags & IRQF_FORCE_RESUME))
411 return;
412 /* Pretend that it got disabled ! */
413 desc->depth++;
414 }
415 desc->istate &= ~IRQS_SUSPENDED;
416 }
417
418 switch (desc->depth) {
419 case 0:
420 err_out:
421 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
422 break;
423 case 1: {
424 if (desc->istate & IRQS_SUSPENDED)
425 goto err_out;
426 /* Prevent probing on this irq: */
427 irq_settings_set_noprobe(desc);
428 irq_enable(desc);
429 check_irq_resend(desc, irq);
430 /* fall-through */
431 }
432 default:
433 desc->depth--;
434 }
435}
436
437/**
438 * enable_irq - enable handling of an irq
439 * @irq: Interrupt to enable
440 *
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.
444 *
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 !
447 */
448void enable_irq(unsigned int irq)
449{
450 unsigned long flags;
451 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags);
452
453 if (!desc)
454 return;
455 if (WARN(!desc->irq_data.chip,
456 KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
457 goto out;
458
459 __enable_irq(desc, irq, false);
460out:
461 irq_put_desc_busunlock(desc, flags);
462}
463EXPORT_SYMBOL(enable_irq);
464
465static int set_irq_wake_real(unsigned int irq, unsigned int on)
466{
467 struct irq_desc *desc = irq_to_desc(irq);
468 int ret = -ENXIO;
469
470 if (desc->irq_data.chip->irq_set_wake)
471 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
472
473 return ret;
474}
475
476/**
477 * irq_set_irq_wake - control irq power management wakeup
478 * @irq: interrupt to control
479 * @on: enable/disable power management wakeup
480 *
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.
484 *
485 * Wakeup mode lets this IRQ wake the system from sleep
486 * states like "suspend to RAM".
487 */
488int irq_set_irq_wake(unsigned int irq, unsigned int on)
489{
490 unsigned long flags;
491 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags);
492 int ret = 0;
493
494 if (!desc)
495 return -EINVAL;
496
497 /* wakeup-capable irqs can be shared between drivers that
498 * don't need to have the same sleep mode behaviors.
499 */
500 if (on) {
501 if (desc->wake_depth++ == 0) {
502 ret = set_irq_wake_real(irq, on);
503 if (ret)
504 desc->wake_depth = 0;
505 else
506 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
507 }
508 } else {
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);
513 if (ret)
514 desc->wake_depth = 1;
515 else
516 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
517 }
518 }
519 irq_put_desc_busunlock(desc, flags);
520 return ret;
521}
522EXPORT_SYMBOL(irq_set_irq_wake);
523
524/*
525 * Internal function that tells the architecture code whether a
526 * particular irq has been exclusively allocated or is available
527 * for driver use.
528 */
529int can_request_irq(unsigned int irq, unsigned long irqflags)
530{
531 unsigned long flags;
532 struct irq_desc *desc = irq_get_desc_lock(irq, &flags);
533 int canrequest = 0;
534
535 if (!desc)
536 return 0;
537
538 if (irq_settings_can_request(desc)) {
539 if (desc->action)
540 if (irqflags & desc->action->flags & IRQF_SHARED)
541 canrequest =1;
542 }
543 irq_put_desc_unlock(desc, flags);
544 return canrequest;
545}
546
547int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
548 unsigned long flags)
549{
550 struct irq_chip *chip = desc->irq_data.chip;
551 int ret, unmask = 0;
552
553 if (!chip || !chip->irq_set_type) {
554 /*
555 * IRQF_TRIGGER_* but the PIC does not support multiple
556 * flow-types?
557 */
558 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
559 chip ? (chip->name ? : "unknown") : "unknown");
560 return 0;
561 }
562
563 flags &= IRQ_TYPE_SENSE_MASK;
564
565 if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
566 if (!irqd_irq_masked(&desc->irq_data))
567 mask_irq(desc);
568 if (!irqd_irq_disabled(&desc->irq_data))
569 unmask = 1;
570 }
571
572 /* caller masked out all except trigger mode flags */
573 ret = chip->irq_set_type(&desc->irq_data, flags);
574
575 switch (ret) {
576 case IRQ_SET_MASK_OK:
577 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
578 irqd_set(&desc->irq_data, flags);
579
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);
588 }
589
590 ret = 0;
591 break;
592 default:
593 pr_err("setting trigger mode %lu for irq %u failed (%pF)\n",
594 flags, irq, chip->irq_set_type);
595 }
596 if (unmask)
597 unmask_irq(desc);
598 return ret;
599}
600
601/*
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.
605 */
606static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
607{
608 return IRQ_WAKE_THREAD;
609}
610
611/*
612 * Primary handler for nested threaded interrupts. Should never be
613 * called.
614 */
615static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
616{
617 WARN(1, "Primary handler called for nested irq %d\n", irq);
618 return IRQ_NONE;
619}
620
621static int irq_wait_for_interrupt(struct irqaction *action)
622{
623 while (!kthread_should_stop()) {
624 set_current_state(TASK_INTERRUPTIBLE);
625
626 if (test_and_clear_bit(IRQTF_RUNTHREAD,
627 &action->thread_flags)) {
628 __set_current_state(TASK_RUNNING);
629 return 0;
630 }
631 schedule();
632 }
633 return -1;
634}
635
636/*
637 * Oneshot interrupts keep the irq line masked until the threaded
638 * handler finished. unmask if the interrupt has not been disabled and
639 * is marked MASKED.
640 */
641static void irq_finalize_oneshot(struct irq_desc *desc,
642 struct irqaction *action, bool force)
643{
644 if (!(desc->istate & IRQS_ONESHOT))
645 return;
646again:
647 chip_bus_lock(desc);
648 raw_spin_lock_irq(&desc->lock);
649
650 /*
651 * Implausible though it may be we need to protect us against
652 * the following scenario:
653 *
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.
658 *
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
662 * serialization.
663 */
664 if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
665 raw_spin_unlock_irq(&desc->lock);
666 chip_bus_sync_unlock(desc);
667 cpu_relax();
668 goto again;
669 }
670
671 /*
672 * Now check again, whether the thread should run. Otherwise
673 * we would clear the threads_oneshot bit of this thread which
674 * was just set.
675 */
676 if (!force && test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
677 goto out_unlock;
678
679 desc->threads_oneshot &= ~action->thread_mask;
680
681 if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
682 irqd_irq_masked(&desc->irq_data))
683 unmask_irq(desc);
684
685out_unlock:
686 raw_spin_unlock_irq(&desc->lock);
687 chip_bus_sync_unlock(desc);
688}
689
690#ifdef CONFIG_SMP
691/*
692 * Check whether we need to chasnge the affinity of the interrupt thread.
693 */
694static void
695irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
696{
697 cpumask_var_t mask;
698
699 if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
700 return;
701
702 /*
703 * In case we are out of memory we set IRQTF_AFFINITY again and
704 * try again next time
705 */
706 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
707 set_bit(IRQTF_AFFINITY, &action->thread_flags);
708 return;
709 }
710
711 raw_spin_lock_irq(&desc->lock);
712 cpumask_copy(mask, desc->irq_data.affinity);
713 raw_spin_unlock_irq(&desc->lock);
714
715 set_cpus_allowed_ptr(current, mask);
716 free_cpumask_var(mask);
717}
718#else
719static inline void
720irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
721#endif
722
723/*
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
727 * side effects.
728 */
729static irqreturn_t
730irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
731{
732 irqreturn_t ret;
733
734 local_bh_disable();
735 ret = action->thread_fn(action->irq, action->dev_id);
736 irq_finalize_oneshot(desc, action, false);
737 local_bh_enable();
738 return ret;
739}
740
741/*
742 * Interrupts explicitely requested as threaded interupts want to be
743 * preemtible - many of them need to sleep and wait for slow busses to
744 * complete.
745 */
746static irqreturn_t irq_thread_fn(struct irq_desc *desc,
747 struct irqaction *action)
748{
749 irqreturn_t ret;
750
751 ret = action->thread_fn(action->irq, action->dev_id);
752 irq_finalize_oneshot(desc, action, false);
753 return ret;
754}
755
756/*
757 * Interrupt handler thread
758 */
759static int irq_thread(void *data)
760{
761 static const struct sched_param param = {
762 .sched_priority = MAX_USER_RT_PRIO/2,
763 };
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);
768 int wake;
769
770 if (force_irqthreads & test_bit(IRQTF_FORCED_THREAD,
771 &action->thread_flags))
772 handler_fn = irq_forced_thread_fn;
773 else
774 handler_fn = irq_thread_fn;
775
776 sched_setscheduler(current, SCHED_FIFO, ¶m);
777 current->irqaction = action;
778
779 while (!irq_wait_for_interrupt(action)) {
780
781 irq_thread_check_affinity(desc, action);
782
783 atomic_inc(&desc->threads_active);
784
785 raw_spin_lock_irq(&desc->lock);
786 if (unlikely(irqd_irq_disabled(&desc->irq_data))) {
787 /*
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
793 */
794 desc->istate |= IRQS_PENDING;
795 raw_spin_unlock_irq(&desc->lock);
796 } else {
797 irqreturn_t action_ret;
798
799 raw_spin_unlock_irq(&desc->lock);
800 action_ret = handler_fn(desc, action);
801 if (!noirqdebug)
802 note_interrupt(action->irq, desc, action_ret);
803 }
804
805 wake = atomic_dec_and_test(&desc->threads_active);
806
807 if (wake && waitqueue_active(&desc->wait_for_threads))
808 wake_up(&desc->wait_for_threads);
809 }
810
811 /* Prevent a stale desc->threads_oneshot */
812 irq_finalize_oneshot(desc, action, true);
813
814 /*
815 * Clear irqaction. Otherwise exit_irq_thread() would make
816 * fuzz about an active irq thread going into nirvana.
817 */
818 current->irqaction = NULL;
819 return 0;
820}
821
822/*
823 * Called from do_exit()
824 */
825void exit_irq_thread(void)
826{
827 struct task_struct *tsk = current;
828 struct irq_desc *desc;
829
830 if (!tsk->irqaction)
831 return;
832
833 printk(KERN_ERR
834 "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
835 tsk->comm ? tsk->comm : "", tsk->pid, tsk->irqaction->irq);
836
837 desc = irq_to_desc(tsk->irqaction->irq);
838
839 /*
840 * Prevent a stale desc->threads_oneshot. Must be called
841 * before setting the IRQTF_DIED flag.
842 */
843 irq_finalize_oneshot(desc, tsk->irqaction, true);
844
845 /*
846 * Set the THREAD DIED flag to prevent further wakeups of the
847 * soon to be gone threaded handler.
848 */
849 set_bit(IRQTF_DIED, &tsk->irqaction->flags);
850}
851
852static void irq_setup_forced_threading(struct irqaction *new)
853{
854 if (!force_irqthreads)
855 return;
856 if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
857 return;
858
859 new->flags |= IRQF_ONESHOT;
860
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;
865 }
866}
867
868/*
869 * Internal function to register an irqaction - typically used to
870 * allocate special interrupts that are part of the architecture.
871 */
872static int
873__setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
874{
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;
879 cpumask_var_t mask;
880
881 if (!desc)
882 return -EINVAL;
883
884 if (desc->irq_data.chip == &no_irq_chip)
885 return -ENOSYS;
886 if (!try_module_get(desc->owner))
887 return -ENODEV;
888 /*
889 * Some drivers like serial.c use request_irq() heavily,
890 * so we have to be careful not to interfere with a
891 * running system.
892 */
893 if (new->flags & IRQF_SAMPLE_RANDOM) {
894 /*
895 * This function might sleep, we want to call it first,
896 * outside of the atomic block.
897 * Yes, this might clear the entropy pool if the wrong
898 * driver is attempted to be loaded, without actually
899 * installing a new handler, but is this really a problem,
900 * only the sysadmin is able to do this.
901 */
902 rand_initialize_irq(irq);
903 }
904
905 /*
906 * Check whether the interrupt nests into another interrupt
907 * thread.
908 */
909 nested = irq_settings_is_nested_thread(desc);
910 if (nested) {
911 if (!new->thread_fn) {
912 ret = -EINVAL;
913 goto out_mput;
914 }
915 /*
916 * Replace the primary handler which was provided from
917 * the driver for non nested interrupt handling by the
918 * dummy function which warns when called.
919 */
920 new->handler = irq_nested_primary_handler;
921 } else {
922 if (irq_settings_can_thread(desc))
923 irq_setup_forced_threading(new);
924 }
925
926 /*
927 * Create a handler thread when a thread function is supplied
928 * and the interrupt does not nest into another interrupt
929 * thread.
930 */
931 if (new->thread_fn && !nested) {
932 struct task_struct *t;
933
934 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
935 new->name);
936 if (IS_ERR(t)) {
937 ret = PTR_ERR(t);
938 goto out_mput;
939 }
940 /*
941 * We keep the reference to the task struct even if
942 * the thread dies to avoid that the interrupt code
943 * references an already freed task_struct.
944 */
945 get_task_struct(t);
946 new->thread = t;
947 }
948
949 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
950 ret = -ENOMEM;
951 goto out_thread;
952 }
953
954 /*
955 * The following block of code has to be executed atomically
956 */
957 raw_spin_lock_irqsave(&desc->lock, flags);
958 old_ptr = &desc->action;
959 old = *old_ptr;
960 if (old) {
961 /*
962 * Can't share interrupts unless both agree to and are
963 * the same type (level, edge, polarity). So both flag
964 * fields must have IRQF_SHARED set and the bits which
965 * set the trigger type must match. Also all must
966 * agree on ONESHOT.
967 */
968 if (!((old->flags & new->flags) & IRQF_SHARED) ||
969 ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
970 ((old->flags ^ new->flags) & IRQF_ONESHOT)) {
971 old_name = old->name;
972 goto mismatch;
973 }
974
975 /* All handlers must agree on per-cpuness */
976 if ((old->flags & IRQF_PERCPU) !=
977 (new->flags & IRQF_PERCPU))
978 goto mismatch;
979
980 /* add new interrupt at end of irq queue */
981 do {
982 thread_mask |= old->thread_mask;
983 old_ptr = &old->next;
984 old = *old_ptr;
985 } while (old);
986 shared = 1;
987 }
988
989 /*
990 * Setup the thread mask for this irqaction. Unlikely to have
991 * 32 resp 64 irqs sharing one line, but who knows.
992 */
993 if (new->flags & IRQF_ONESHOT && thread_mask == ~0UL) {
994 ret = -EBUSY;
995 goto out_mask;
996 }
997 new->thread_mask = 1 << ffz(thread_mask);
998
999 if (!shared) {
1000 init_waitqueue_head(&desc->wait_for_threads);
1001
1002 /* Setup the type (level, edge polarity) if configured: */
1003 if (new->flags & IRQF_TRIGGER_MASK) {
1004 ret = __irq_set_trigger(desc, irq,
1005 new->flags & IRQF_TRIGGER_MASK);
1006
1007 if (ret)
1008 goto out_mask;
1009 }
1010
1011 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1012 IRQS_ONESHOT | IRQS_WAITING);
1013 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1014
1015 if (new->flags & IRQF_PERCPU) {
1016 irqd_set(&desc->irq_data, IRQD_PER_CPU);
1017 irq_settings_set_per_cpu(desc);
1018 }
1019
1020 if (new->flags & IRQF_ONESHOT)
1021 desc->istate |= IRQS_ONESHOT;
1022
1023 if (irq_settings_can_autoenable(desc))
1024 irq_startup(desc);
1025 else
1026 /* Undo nested disables: */
1027 desc->depth = 1;
1028
1029 /* Exclude IRQ from balancing if requested */
1030 if (new->flags & IRQF_NOBALANCING) {
1031 irq_settings_set_no_balancing(desc);
1032 irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1033 }
1034
1035 /* Set default affinity mask once everything is setup */
1036 setup_affinity(irq, desc, mask);
1037
1038 } else if (new->flags & IRQF_TRIGGER_MASK) {
1039 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1040 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1041
1042 if (nmsk != omsk)
1043 /* hope the handler works with current trigger mode */
1044 pr_warning("IRQ %d uses trigger mode %u; requested %u\n",
1045 irq, nmsk, omsk);
1046 }
1047
1048 new->irq = irq;
1049 *old_ptr = new;
1050
1051 /* Reset broken irq detection when installing new handler */
1052 desc->irq_count = 0;
1053 desc->irqs_unhandled = 0;
1054
1055 /*
1056 * Check whether we disabled the irq via the spurious handler
1057 * before. Reenable it and give it another chance.
1058 */
1059 if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1060 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1061 __enable_irq(desc, irq, false);
1062 }
1063
1064 raw_spin_unlock_irqrestore(&desc->lock, flags);
1065
1066 /*
1067 * Strictly no need to wake it up, but hung_task complains
1068 * when no hard interrupt wakes the thread up.
1069 */
1070 if (new->thread)
1071 wake_up_process(new->thread);
1072
1073 register_irq_proc(irq, desc);
1074 new->dir = NULL;
1075 register_handler_proc(irq, new);
1076 free_cpumask_var(mask);
1077
1078 return 0;
1079
1080mismatch:
1081#ifdef CONFIG_DEBUG_SHIRQ
1082 if (!(new->flags & IRQF_PROBE_SHARED)) {
1083 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
1084 if (old_name)
1085 printk(KERN_ERR "current handler: %s\n", old_name);
1086 dump_stack();
1087 }
1088#endif
1089 ret = -EBUSY;
1090
1091out_mask:
1092 raw_spin_unlock_irqrestore(&desc->lock, flags);
1093 free_cpumask_var(mask);
1094
1095out_thread:
1096 if (new->thread) {
1097 struct task_struct *t = new->thread;
1098
1099 new->thread = NULL;
1100 if (likely(!test_bit(IRQTF_DIED, &new->thread_flags)))
1101 kthread_stop(t);
1102 put_task_struct(t);
1103 }
1104out_mput:
1105 module_put(desc->owner);
1106 return ret;
1107}
1108
1109/**
1110 * setup_irq - setup an interrupt
1111 * @irq: Interrupt line to setup
1112 * @act: irqaction for the interrupt
1113 *
1114 * Used to statically setup interrupts in the early boot process.
1115 */
1116int setup_irq(unsigned int irq, struct irqaction *act)
1117{
1118 int retval;
1119 struct irq_desc *desc = irq_to_desc(irq);
1120
1121 chip_bus_lock(desc);
1122 retval = __setup_irq(irq, desc, act);
1123 chip_bus_sync_unlock(desc);
1124
1125 return retval;
1126}
1127EXPORT_SYMBOL_GPL(setup_irq);
1128
1129 /*
1130 * Internal function to unregister an irqaction - used to free
1131 * regular and special interrupts that are part of the architecture.
1132 */
1133static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1134{
1135 struct irq_desc *desc = irq_to_desc(irq);
1136 struct irqaction *action, **action_ptr;
1137 unsigned long flags;
1138
1139 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1140
1141 if (!desc)
1142 return NULL;
1143
1144 raw_spin_lock_irqsave(&desc->lock, flags);
1145
1146 /*
1147 * There can be multiple actions per IRQ descriptor, find the right
1148 * one based on the dev_id:
1149 */
1150 action_ptr = &desc->action;
1151 for (;;) {
1152 action = *action_ptr;
1153
1154 if (!action) {
1155 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1156 raw_spin_unlock_irqrestore(&desc->lock, flags);
1157
1158 return NULL;
1159 }
1160
1161 if (action->dev_id == dev_id)
1162 break;
1163 action_ptr = &action->next;
1164 }
1165
1166 /* Found it - now remove it from the list of entries: */
1167 *action_ptr = action->next;
1168
1169 /* Currently used only by UML, might disappear one day: */
1170#ifdef CONFIG_IRQ_RELEASE_METHOD
1171 if (desc->irq_data.chip->release)
1172 desc->irq_data.chip->release(irq, dev_id);
1173#endif
1174
1175 /* If this was the last handler, shut down the IRQ line: */
1176 if (!desc->action)
1177 irq_shutdown(desc);
1178
1179#ifdef CONFIG_SMP
1180 /* make sure affinity_hint is cleaned up */
1181 if (WARN_ON_ONCE(desc->affinity_hint))
1182 desc->affinity_hint = NULL;
1183#endif
1184
1185 raw_spin_unlock_irqrestore(&desc->lock, flags);
1186
1187 unregister_handler_proc(irq, action);
1188
1189 /* Make sure it's not being used on another CPU: */
1190 synchronize_irq(irq);
1191
1192#ifdef CONFIG_DEBUG_SHIRQ
1193 /*
1194 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1195 * event to happen even now it's being freed, so let's make sure that
1196 * is so by doing an extra call to the handler ....
1197 *
1198 * ( We do this after actually deregistering it, to make sure that a
1199 * 'real' IRQ doesn't run in * parallel with our fake. )
1200 */
1201 if (action->flags & IRQF_SHARED) {
1202 local_irq_save(flags);
1203 action->handler(irq, dev_id);
1204 local_irq_restore(flags);
1205 }
1206#endif
1207
1208 if (action->thread) {
1209 if (!test_bit(IRQTF_DIED, &action->thread_flags))
1210 kthread_stop(action->thread);
1211 put_task_struct(action->thread);
1212 }
1213
1214 module_put(desc->owner);
1215 return action;
1216}
1217
1218/**
1219 * remove_irq - free an interrupt
1220 * @irq: Interrupt line to free
1221 * @act: irqaction for the interrupt
1222 *
1223 * Used to remove interrupts statically setup by the early boot process.
1224 */
1225void remove_irq(unsigned int irq, struct irqaction *act)
1226{
1227 __free_irq(irq, act->dev_id);
1228}
1229EXPORT_SYMBOL_GPL(remove_irq);
1230
1231/**
1232 * free_irq - free an interrupt allocated with request_irq
1233 * @irq: Interrupt line to free
1234 * @dev_id: Device identity to free
1235 *
1236 * Remove an interrupt handler. The handler is removed and if the
1237 * interrupt line is no longer in use by any driver it is disabled.
1238 * On a shared IRQ the caller must ensure the interrupt is disabled
1239 * on the card it drives before calling this function. The function
1240 * does not return until any executing interrupts for this IRQ
1241 * have completed.
1242 *
1243 * This function must not be called from interrupt context.
1244 */
1245void free_irq(unsigned int irq, void *dev_id)
1246{
1247 struct irq_desc *desc = irq_to_desc(irq);
1248
1249 if (!desc)
1250 return;
1251
1252#ifdef CONFIG_SMP
1253 if (WARN_ON(desc->affinity_notify))
1254 desc->affinity_notify = NULL;
1255#endif
1256
1257 chip_bus_lock(desc);
1258 kfree(__free_irq(irq, dev_id));
1259 chip_bus_sync_unlock(desc);
1260}
1261EXPORT_SYMBOL(free_irq);
1262
1263/**
1264 * request_threaded_irq - allocate an interrupt line
1265 * @irq: Interrupt line to allocate
1266 * @handler: Function to be called when the IRQ occurs.
1267 * Primary handler for threaded interrupts
1268 * If NULL and thread_fn != NULL the default
1269 * primary handler is installed
1270 * @thread_fn: Function called from the irq handler thread
1271 * If NULL, no irq thread is created
1272 * @irqflags: Interrupt type flags
1273 * @devname: An ascii name for the claiming device
1274 * @dev_id: A cookie passed back to the handler function
1275 *
1276 * This call allocates interrupt resources and enables the
1277 * interrupt line and IRQ handling. From the point this
1278 * call is made your handler function may be invoked. Since
1279 * your handler function must clear any interrupt the board
1280 * raises, you must take care both to initialise your hardware
1281 * and to set up the interrupt handler in the right order.
1282 *
1283 * If you want to set up a threaded irq handler for your device
1284 * then you need to supply @handler and @thread_fn. @handler ist
1285 * still called in hard interrupt context and has to check
1286 * whether the interrupt originates from the device. If yes it
1287 * needs to disable the interrupt on the device and return
1288 * IRQ_WAKE_THREAD which will wake up the handler thread and run
1289 * @thread_fn. This split handler design is necessary to support
1290 * shared interrupts.
1291 *
1292 * Dev_id must be globally unique. Normally the address of the
1293 * device data structure is used as the cookie. Since the handler
1294 * receives this value it makes sense to use it.
1295 *
1296 * If your interrupt is shared you must pass a non NULL dev_id
1297 * as this is required when freeing the interrupt.
1298 *
1299 * Flags:
1300 *
1301 * IRQF_SHARED Interrupt is shared
1302 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
1303 * IRQF_TRIGGER_* Specify active edge(s) or level
1304 *
1305 */
1306int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1307 irq_handler_t thread_fn, unsigned long irqflags,
1308 const char *devname, void *dev_id)
1309{
1310 struct irqaction *action;
1311 struct irq_desc *desc;
1312 int retval;
1313
1314 /*
1315 * Sanity-check: shared interrupts must pass in a real dev-ID,
1316 * otherwise we'll have trouble later trying to figure out
1317 * which interrupt is which (messes up the interrupt freeing
1318 * logic etc).
1319 */
1320 if ((irqflags & IRQF_SHARED) && !dev_id)
1321 return -EINVAL;
1322
1323 desc = irq_to_desc(irq);
1324 if (!desc)
1325 return -EINVAL;
1326
1327 if (!irq_settings_can_request(desc))
1328 return -EINVAL;
1329
1330 if (!handler) {
1331 if (!thread_fn)
1332 return -EINVAL;
1333 handler = irq_default_primary_handler;
1334 }
1335
1336 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1337 if (!action)
1338 return -ENOMEM;
1339
1340 action->handler = handler;
1341 action->thread_fn = thread_fn;
1342 action->flags = irqflags;
1343 action->name = devname;
1344 action->dev_id = dev_id;
1345
1346 chip_bus_lock(desc);
1347 retval = __setup_irq(irq, desc, action);
1348 chip_bus_sync_unlock(desc);
1349
1350 if (retval)
1351 kfree(action);
1352
1353#ifdef CONFIG_DEBUG_SHIRQ_FIXME
1354 if (!retval && (irqflags & IRQF_SHARED)) {
1355 /*
1356 * It's a shared IRQ -- the driver ought to be prepared for it
1357 * to happen immediately, so let's make sure....
1358 * We disable the irq to make sure that a 'real' IRQ doesn't
1359 * run in parallel with our fake.
1360 */
1361 unsigned long flags;
1362
1363 disable_irq(irq);
1364 local_irq_save(flags);
1365
1366 handler(irq, dev_id);
1367
1368 local_irq_restore(flags);
1369 enable_irq(irq);
1370 }
1371#endif
1372 return retval;
1373}
1374EXPORT_SYMBOL(request_threaded_irq);
1375
1376/**
1377 * request_any_context_irq - allocate an interrupt line
1378 * @irq: Interrupt line to allocate
1379 * @handler: Function to be called when the IRQ occurs.
1380 * Threaded handler for threaded interrupts.
1381 * @flags: Interrupt type flags
1382 * @name: An ascii name for the claiming device
1383 * @dev_id: A cookie passed back to the handler function
1384 *
1385 * This call allocates interrupt resources and enables the
1386 * interrupt line and IRQ handling. It selects either a
1387 * hardirq or threaded handling method depending on the
1388 * context.
1389 *
1390 * On failure, it returns a negative value. On success,
1391 * it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1392 */
1393int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1394 unsigned long flags, const char *name, void *dev_id)
1395{
1396 struct irq_desc *desc = irq_to_desc(irq);
1397 int ret;
1398
1399 if (!desc)
1400 return -EINVAL;
1401
1402 if (irq_settings_is_nested_thread(desc)) {
1403 ret = request_threaded_irq(irq, NULL, handler,
1404 flags, name, dev_id);
1405 return !ret ? IRQC_IS_NESTED : ret;
1406 }
1407
1408 ret = request_irq(irq, handler, flags, name, dev_id);
1409 return !ret ? IRQC_IS_HARDIRQ : ret;
1410}
1411EXPORT_SYMBOL_GPL(request_any_context_irq);