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Linux/kernel/irq/manage.c

  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 #define pr_fmt(fmt) "genirq: " fmt
 11 
 12 #include <linux/irq.h>
 13 #include <linux/kthread.h>
 14 #include <linux/module.h>
 15 #include <linux/random.h>
 16 #include <linux/interrupt.h>
 17 #include <linux/slab.h>
 18 #include <linux/sched.h>
 19 #include <linux/sched/rt.h>
 20 #include <linux/task_work.h>
 21 
 22 #include "internals.h"
 23 
 24 #ifdef CONFIG_IRQ_FORCED_THREADING
 25 __read_mostly bool force_irqthreads;
 26 
 27 static int __init setup_forced_irqthreads(char *arg)
 28 {
 29         force_irqthreads = true;
 30         return 0;
 31 }
 32 early_param("threadirqs", setup_forced_irqthreads);
 33 #endif
 34 
 35 static void __synchronize_hardirq(struct irq_desc *desc)
 36 {
 37         bool inprogress;
 38 
 39         do {
 40                 unsigned long flags;
 41 
 42                 /*
 43                  * Wait until we're out of the critical section.  This might
 44                  * give the wrong answer due to the lack of memory barriers.
 45                  */
 46                 while (irqd_irq_inprogress(&desc->irq_data))
 47                         cpu_relax();
 48 
 49                 /* Ok, that indicated we're done: double-check carefully. */
 50                 raw_spin_lock_irqsave(&desc->lock, flags);
 51                 inprogress = irqd_irq_inprogress(&desc->irq_data);
 52                 raw_spin_unlock_irqrestore(&desc->lock, flags);
 53 
 54                 /* Oops, that failed? */
 55         } while (inprogress);
 56 }
 57 
 58 /**
 59  *      synchronize_hardirq - wait for pending hard IRQ handlers (on other CPUs)
 60  *      @irq: interrupt number to wait for
 61  *
 62  *      This function waits for any pending hard IRQ handlers for this
 63  *      interrupt to complete before returning. If you use this
 64  *      function while holding a resource the IRQ handler may need you
 65  *      will deadlock. It does not take associated threaded handlers
 66  *      into account.
 67  *
 68  *      Do not use this for shutdown scenarios where you must be sure
 69  *      that all parts (hardirq and threaded handler) have completed.
 70  *
 71  *      This function may be called - with care - from IRQ context.
 72  */
 73 void synchronize_hardirq(unsigned int irq)
 74 {
 75         struct irq_desc *desc = irq_to_desc(irq);
 76 
 77         if (desc)
 78                 __synchronize_hardirq(desc);
 79 }
 80 EXPORT_SYMBOL(synchronize_hardirq);
 81 
 82 /**
 83  *      synchronize_irq - wait for pending IRQ handlers (on other CPUs)
 84  *      @irq: interrupt number to wait for
 85  *
 86  *      This function waits for any pending IRQ handlers for this interrupt
 87  *      to complete before returning. If you use this function while
 88  *      holding a resource the IRQ handler may need you will deadlock.
 89  *
 90  *      This function may be called - with care - from IRQ context.
 91  */
 92 void synchronize_irq(unsigned int irq)
 93 {
 94         struct irq_desc *desc = irq_to_desc(irq);
 95 
 96         if (desc) {
 97                 __synchronize_hardirq(desc);
 98                 /*
 99                  * We made sure that no hardirq handler is
100                  * running. Now verify that no threaded handlers are
101                  * active.
102                  */
103                 wait_event(desc->wait_for_threads,
104                            !atomic_read(&desc->threads_active));
105         }
106 }
107 EXPORT_SYMBOL(synchronize_irq);
108 
109 #ifdef CONFIG_SMP
110 cpumask_var_t irq_default_affinity;
111 
112 /**
113  *      irq_can_set_affinity - Check if the affinity of a given irq can be set
114  *      @irq:           Interrupt to check
115  *
116  */
117 int irq_can_set_affinity(unsigned int irq)
118 {
119         struct irq_desc *desc = irq_to_desc(irq);
120 
121         if (!desc || !irqd_can_balance(&desc->irq_data) ||
122             !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
123                 return 0;
124 
125         return 1;
126 }
127 
128 /**
129  *      irq_set_thread_affinity - Notify irq threads to adjust affinity
130  *      @desc:          irq descriptor which has affitnity changed
131  *
132  *      We just set IRQTF_AFFINITY and delegate the affinity setting
133  *      to the interrupt thread itself. We can not call
134  *      set_cpus_allowed_ptr() here as we hold desc->lock and this
135  *      code can be called from hard interrupt context.
136  */
137 void irq_set_thread_affinity(struct irq_desc *desc)
138 {
139         struct irqaction *action = desc->action;
140 
141         while (action) {
142                 if (action->thread)
143                         set_bit(IRQTF_AFFINITY, &action->thread_flags);
144                 action = action->next;
145         }
146 }
147 
148 #ifdef CONFIG_GENERIC_PENDING_IRQ
149 static inline bool irq_can_move_pcntxt(struct irq_data *data)
150 {
151         return irqd_can_move_in_process_context(data);
152 }
153 static inline bool irq_move_pending(struct irq_data *data)
154 {
155         return irqd_is_setaffinity_pending(data);
156 }
157 static inline void
158 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
159 {
160         cpumask_copy(desc->pending_mask, mask);
161 }
162 static inline void
163 irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
164 {
165         cpumask_copy(mask, desc->pending_mask);
166 }
167 #else
168 static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
169 static inline bool irq_move_pending(struct irq_data *data) { return false; }
170 static inline void
171 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
172 static inline void
173 irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
174 #endif
175 
176 int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
177                         bool force)
178 {
179         struct irq_desc *desc = irq_data_to_desc(data);
180         struct irq_chip *chip = irq_data_get_irq_chip(data);
181         int ret;
182 
183         ret = chip->irq_set_affinity(data, mask, force);
184         switch (ret) {
185         case IRQ_SET_MASK_OK:
186                 cpumask_copy(data->affinity, mask);
187         case IRQ_SET_MASK_OK_NOCOPY:
188                 irq_set_thread_affinity(desc);
189                 ret = 0;
190         }
191 
192         return ret;
193 }
194 
195 int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
196                             bool force)
197 {
198         struct irq_chip *chip = irq_data_get_irq_chip(data);
199         struct irq_desc *desc = irq_data_to_desc(data);
200         int ret = 0;
201 
202         if (!chip || !chip->irq_set_affinity)
203                 return -EINVAL;
204 
205         if (irq_can_move_pcntxt(data)) {
206                 ret = irq_do_set_affinity(data, mask, force);
207         } else {
208                 irqd_set_move_pending(data);
209                 irq_copy_pending(desc, mask);
210         }
211 
212         if (desc->affinity_notify) {
213                 kref_get(&desc->affinity_notify->kref);
214                 schedule_work(&desc->affinity_notify->work);
215         }
216         irqd_set(data, IRQD_AFFINITY_SET);
217 
218         return ret;
219 }
220 
221 int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
222 {
223         struct irq_desc *desc = irq_to_desc(irq);
224         unsigned long flags;
225         int ret;
226 
227         if (!desc)
228                 return -EINVAL;
229 
230         raw_spin_lock_irqsave(&desc->lock, flags);
231         ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force);
232         raw_spin_unlock_irqrestore(&desc->lock, flags);
233         return ret;
234 }
235 
236 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
237 {
238         unsigned long flags;
239         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
240 
241         if (!desc)
242                 return -EINVAL;
243         desc->affinity_hint = m;
244         irq_put_desc_unlock(desc, flags);
245         return 0;
246 }
247 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
248 
249 static void irq_affinity_notify(struct work_struct *work)
250 {
251         struct irq_affinity_notify *notify =
252                 container_of(work, struct irq_affinity_notify, work);
253         struct irq_desc *desc = irq_to_desc(notify->irq);
254         cpumask_var_t cpumask;
255         unsigned long flags;
256 
257         if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
258                 goto out;
259 
260         raw_spin_lock_irqsave(&desc->lock, flags);
261         if (irq_move_pending(&desc->irq_data))
262                 irq_get_pending(cpumask, desc);
263         else
264                 cpumask_copy(cpumask, desc->irq_data.affinity);
265         raw_spin_unlock_irqrestore(&desc->lock, flags);
266 
267         notify->notify(notify, cpumask);
268 
269         free_cpumask_var(cpumask);
270 out:
271         kref_put(&notify->kref, notify->release);
272 }
273 
274 /**
275  *      irq_set_affinity_notifier - control notification of IRQ affinity changes
276  *      @irq:           Interrupt for which to enable/disable notification
277  *      @notify:        Context for notification, or %NULL to disable
278  *                      notification.  Function pointers must be initialised;
279  *                      the other fields will be initialised by this function.
280  *
281  *      Must be called in process context.  Notification may only be enabled
282  *      after the IRQ is allocated and must be disabled before the IRQ is
283  *      freed using free_irq().
284  */
285 int
286 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
287 {
288         struct irq_desc *desc = irq_to_desc(irq);
289         struct irq_affinity_notify *old_notify;
290         unsigned long flags;
291 
292         /* The release function is promised process context */
293         might_sleep();
294 
295         if (!desc)
296                 return -EINVAL;
297 
298         /* Complete initialisation of *notify */
299         if (notify) {
300                 notify->irq = irq;
301                 kref_init(&notify->kref);
302                 INIT_WORK(&notify->work, irq_affinity_notify);
303         }
304 
305         raw_spin_lock_irqsave(&desc->lock, flags);
306         old_notify = desc->affinity_notify;
307         desc->affinity_notify = notify;
308         raw_spin_unlock_irqrestore(&desc->lock, flags);
309 
310         if (old_notify)
311                 kref_put(&old_notify->kref, old_notify->release);
312 
313         return 0;
314 }
315 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
316 
317 #ifndef CONFIG_AUTO_IRQ_AFFINITY
318 /*
319  * Generic version of the affinity autoselector.
320  */
321 static int
322 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
323 {
324         struct cpumask *set = irq_default_affinity;
325         int node = desc->irq_data.node;
326 
327         /* Excludes PER_CPU and NO_BALANCE interrupts */
328         if (!irq_can_set_affinity(irq))
329                 return 0;
330 
331         /*
332          * Preserve an userspace affinity setup, but make sure that
333          * one of the targets is online.
334          */
335         if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
336                 if (cpumask_intersects(desc->irq_data.affinity,
337                                        cpu_online_mask))
338                         set = desc->irq_data.affinity;
339                 else
340                         irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
341         }
342 
343         cpumask_and(mask, cpu_online_mask, set);
344         if (node != NUMA_NO_NODE) {
345                 const struct cpumask *nodemask = cpumask_of_node(node);
346 
347                 /* make sure at least one of the cpus in nodemask is online */
348                 if (cpumask_intersects(mask, nodemask))
349                         cpumask_and(mask, mask, nodemask);
350         }
351         irq_do_set_affinity(&desc->irq_data, mask, false);
352         return 0;
353 }
354 #else
355 static inline int
356 setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
357 {
358         return irq_select_affinity(irq);
359 }
360 #endif
361 
362 /*
363  * Called when affinity is set via /proc/irq
364  */
365 int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
366 {
367         struct irq_desc *desc = irq_to_desc(irq);
368         unsigned long flags;
369         int ret;
370 
371         raw_spin_lock_irqsave(&desc->lock, flags);
372         ret = setup_affinity(irq, desc, mask);
373         raw_spin_unlock_irqrestore(&desc->lock, flags);
374         return ret;
375 }
376 
377 #else
378 static inline int
379 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
380 {
381         return 0;
382 }
383 #endif
384 
385 void __disable_irq(struct irq_desc *desc, unsigned int irq)
386 {
387         if (!desc->depth++)
388                 irq_disable(desc);
389 }
390 
391 static int __disable_irq_nosync(unsigned int irq)
392 {
393         unsigned long flags;
394         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
395 
396         if (!desc)
397                 return -EINVAL;
398         __disable_irq(desc, irq);
399         irq_put_desc_busunlock(desc, flags);
400         return 0;
401 }
402 
403 /**
404  *      disable_irq_nosync - disable an irq without waiting
405  *      @irq: Interrupt to disable
406  *
407  *      Disable the selected interrupt line.  Disables and Enables are
408  *      nested.
409  *      Unlike disable_irq(), this function does not ensure existing
410  *      instances of the IRQ handler have completed before returning.
411  *
412  *      This function may be called from IRQ context.
413  */
414 void disable_irq_nosync(unsigned int irq)
415 {
416         __disable_irq_nosync(irq);
417 }
418 EXPORT_SYMBOL(disable_irq_nosync);
419 
420 /**
421  *      disable_irq - disable an irq and wait for completion
422  *      @irq: Interrupt to disable
423  *
424  *      Disable the selected interrupt line.  Enables and Disables are
425  *      nested.
426  *      This function waits for any pending IRQ handlers for this interrupt
427  *      to complete before returning. If you use this function while
428  *      holding a resource the IRQ handler may need you will deadlock.
429  *
430  *      This function may be called - with care - from IRQ context.
431  */
432 void disable_irq(unsigned int irq)
433 {
434         if (!__disable_irq_nosync(irq))
435                 synchronize_irq(irq);
436 }
437 EXPORT_SYMBOL(disable_irq);
438 
439 void __enable_irq(struct irq_desc *desc, unsigned int irq)
440 {
441         switch (desc->depth) {
442         case 0:
443  err_out:
444                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
445                 break;
446         case 1: {
447                 if (desc->istate & IRQS_SUSPENDED)
448                         goto err_out;
449                 /* Prevent probing on this irq: */
450                 irq_settings_set_noprobe(desc);
451                 irq_enable(desc);
452                 check_irq_resend(desc, irq);
453                 /* fall-through */
454         }
455         default:
456                 desc->depth--;
457         }
458 }
459 
460 /**
461  *      enable_irq - enable handling of an irq
462  *      @irq: Interrupt to enable
463  *
464  *      Undoes the effect of one call to disable_irq().  If this
465  *      matches the last disable, processing of interrupts on this
466  *      IRQ line is re-enabled.
467  *
468  *      This function may be called from IRQ context only when
469  *      desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
470  */
471 void enable_irq(unsigned int irq)
472 {
473         unsigned long flags;
474         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
475 
476         if (!desc)
477                 return;
478         if (WARN(!desc->irq_data.chip,
479                  KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
480                 goto out;
481 
482         __enable_irq(desc, irq);
483 out:
484         irq_put_desc_busunlock(desc, flags);
485 }
486 EXPORT_SYMBOL(enable_irq);
487 
488 static int set_irq_wake_real(unsigned int irq, unsigned int on)
489 {
490         struct irq_desc *desc = irq_to_desc(irq);
491         int ret = -ENXIO;
492 
493         if (irq_desc_get_chip(desc)->flags &  IRQCHIP_SKIP_SET_WAKE)
494                 return 0;
495 
496         if (desc->irq_data.chip->irq_set_wake)
497                 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
498 
499         return ret;
500 }
501 
502 /**
503  *      irq_set_irq_wake - control irq power management wakeup
504  *      @irq:   interrupt to control
505  *      @on:    enable/disable power management wakeup
506  *
507  *      Enable/disable power management wakeup mode, which is
508  *      disabled by default.  Enables and disables must match,
509  *      just as they match for non-wakeup mode support.
510  *
511  *      Wakeup mode lets this IRQ wake the system from sleep
512  *      states like "suspend to RAM".
513  */
514 int irq_set_irq_wake(unsigned int irq, unsigned int on)
515 {
516         unsigned long flags;
517         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
518         int ret = 0;
519 
520         if (!desc)
521                 return -EINVAL;
522 
523         /* wakeup-capable irqs can be shared between drivers that
524          * don't need to have the same sleep mode behaviors.
525          */
526         if (on) {
527                 if (desc->wake_depth++ == 0) {
528                         ret = set_irq_wake_real(irq, on);
529                         if (ret)
530                                 desc->wake_depth = 0;
531                         else
532                                 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
533                 }
534         } else {
535                 if (desc->wake_depth == 0) {
536                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
537                 } else if (--desc->wake_depth == 0) {
538                         ret = set_irq_wake_real(irq, on);
539                         if (ret)
540                                 desc->wake_depth = 1;
541                         else
542                                 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
543                 }
544         }
545         irq_put_desc_busunlock(desc, flags);
546         return ret;
547 }
548 EXPORT_SYMBOL(irq_set_irq_wake);
549 
550 /*
551  * Internal function that tells the architecture code whether a
552  * particular irq has been exclusively allocated or is available
553  * for driver use.
554  */
555 int can_request_irq(unsigned int irq, unsigned long irqflags)
556 {
557         unsigned long flags;
558         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
559         int canrequest = 0;
560 
561         if (!desc)
562                 return 0;
563 
564         if (irq_settings_can_request(desc)) {
565                 if (!desc->action ||
566                     irqflags & desc->action->flags & IRQF_SHARED)
567                         canrequest = 1;
568         }
569         irq_put_desc_unlock(desc, flags);
570         return canrequest;
571 }
572 
573 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
574                       unsigned long flags)
575 {
576         struct irq_chip *chip = desc->irq_data.chip;
577         int ret, unmask = 0;
578 
579         if (!chip || !chip->irq_set_type) {
580                 /*
581                  * IRQF_TRIGGER_* but the PIC does not support multiple
582                  * flow-types?
583                  */
584                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
585                          chip ? (chip->name ? : "unknown") : "unknown");
586                 return 0;
587         }
588 
589         flags &= IRQ_TYPE_SENSE_MASK;
590 
591         if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
592                 if (!irqd_irq_masked(&desc->irq_data))
593                         mask_irq(desc);
594                 if (!irqd_irq_disabled(&desc->irq_data))
595                         unmask = 1;
596         }
597 
598         /* caller masked out all except trigger mode flags */
599         ret = chip->irq_set_type(&desc->irq_data, flags);
600 
601         switch (ret) {
602         case IRQ_SET_MASK_OK:
603                 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
604                 irqd_set(&desc->irq_data, flags);
605 
606         case IRQ_SET_MASK_OK_NOCOPY:
607                 flags = irqd_get_trigger_type(&desc->irq_data);
608                 irq_settings_set_trigger_mask(desc, flags);
609                 irqd_clear(&desc->irq_data, IRQD_LEVEL);
610                 irq_settings_clr_level(desc);
611                 if (flags & IRQ_TYPE_LEVEL_MASK) {
612                         irq_settings_set_level(desc);
613                         irqd_set(&desc->irq_data, IRQD_LEVEL);
614                 }
615 
616                 ret = 0;
617                 break;
618         default:
619                 pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
620                        flags, irq, chip->irq_set_type);
621         }
622         if (unmask)
623                 unmask_irq(desc);
624         return ret;
625 }
626 
627 #ifdef CONFIG_HARDIRQS_SW_RESEND
628 int irq_set_parent(int irq, int parent_irq)
629 {
630         unsigned long flags;
631         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
632 
633         if (!desc)
634                 return -EINVAL;
635 
636         desc->parent_irq = parent_irq;
637 
638         irq_put_desc_unlock(desc, flags);
639         return 0;
640 }
641 #endif
642 
643 /*
644  * Default primary interrupt handler for threaded interrupts. Is
645  * assigned as primary handler when request_threaded_irq is called
646  * with handler == NULL. Useful for oneshot interrupts.
647  */
648 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
649 {
650         return IRQ_WAKE_THREAD;
651 }
652 
653 /*
654  * Primary handler for nested threaded interrupts. Should never be
655  * called.
656  */
657 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
658 {
659         WARN(1, "Primary handler called for nested irq %d\n", irq);
660         return IRQ_NONE;
661 }
662 
663 static int irq_wait_for_interrupt(struct irqaction *action)
664 {
665         set_current_state(TASK_INTERRUPTIBLE);
666 
667         while (!kthread_should_stop()) {
668 
669                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
670                                        &action->thread_flags)) {
671                         __set_current_state(TASK_RUNNING);
672                         return 0;
673                 }
674                 schedule();
675                 set_current_state(TASK_INTERRUPTIBLE);
676         }
677         __set_current_state(TASK_RUNNING);
678         return -1;
679 }
680 
681 /*
682  * Oneshot interrupts keep the irq line masked until the threaded
683  * handler finished. unmask if the interrupt has not been disabled and
684  * is marked MASKED.
685  */
686 static void irq_finalize_oneshot(struct irq_desc *desc,
687                                  struct irqaction *action)
688 {
689         if (!(desc->istate & IRQS_ONESHOT))
690                 return;
691 again:
692         chip_bus_lock(desc);
693         raw_spin_lock_irq(&desc->lock);
694 
695         /*
696          * Implausible though it may be we need to protect us against
697          * the following scenario:
698          *
699          * The thread is faster done than the hard interrupt handler
700          * on the other CPU. If we unmask the irq line then the
701          * interrupt can come in again and masks the line, leaves due
702          * to IRQS_INPROGRESS and the irq line is masked forever.
703          *
704          * This also serializes the state of shared oneshot handlers
705          * versus "desc->threads_onehsot |= action->thread_mask;" in
706          * irq_wake_thread(). See the comment there which explains the
707          * serialization.
708          */
709         if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
710                 raw_spin_unlock_irq(&desc->lock);
711                 chip_bus_sync_unlock(desc);
712                 cpu_relax();
713                 goto again;
714         }
715 
716         /*
717          * Now check again, whether the thread should run. Otherwise
718          * we would clear the threads_oneshot bit of this thread which
719          * was just set.
720          */
721         if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
722                 goto out_unlock;
723 
724         desc->threads_oneshot &= ~action->thread_mask;
725 
726         if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
727             irqd_irq_masked(&desc->irq_data))
728                 unmask_threaded_irq(desc);
729 
730 out_unlock:
731         raw_spin_unlock_irq(&desc->lock);
732         chip_bus_sync_unlock(desc);
733 }
734 
735 #ifdef CONFIG_SMP
736 /*
737  * Check whether we need to change the affinity of the interrupt thread.
738  */
739 static void
740 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
741 {
742         cpumask_var_t mask;
743         bool valid = true;
744 
745         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
746                 return;
747 
748         /*
749          * In case we are out of memory we set IRQTF_AFFINITY again and
750          * try again next time
751          */
752         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
753                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
754                 return;
755         }
756 
757         raw_spin_lock_irq(&desc->lock);
758         /*
759          * This code is triggered unconditionally. Check the affinity
760          * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
761          */
762         if (desc->irq_data.affinity)
763                 cpumask_copy(mask, desc->irq_data.affinity);
764         else
765                 valid = false;
766         raw_spin_unlock_irq(&desc->lock);
767 
768         if (valid)
769                 set_cpus_allowed_ptr(current, mask);
770         free_cpumask_var(mask);
771 }
772 #else
773 static inline void
774 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
775 #endif
776 
777 /*
778  * Interrupts which are not explicitely requested as threaded
779  * interrupts rely on the implicit bh/preempt disable of the hard irq
780  * context. So we need to disable bh here to avoid deadlocks and other
781  * side effects.
782  */
783 static irqreturn_t
784 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
785 {
786         irqreturn_t ret;
787 
788         local_bh_disable();
789         ret = action->thread_fn(action->irq, action->dev_id);
790         irq_finalize_oneshot(desc, action);
791         local_bh_enable();
792         return ret;
793 }
794 
795 /*
796  * Interrupts explicitly requested as threaded interrupts want to be
797  * preemtible - many of them need to sleep and wait for slow busses to
798  * complete.
799  */
800 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
801                 struct irqaction *action)
802 {
803         irqreturn_t ret;
804 
805         ret = action->thread_fn(action->irq, action->dev_id);
806         irq_finalize_oneshot(desc, action);
807         return ret;
808 }
809 
810 static void wake_threads_waitq(struct irq_desc *desc)
811 {
812         if (atomic_dec_and_test(&desc->threads_active))
813                 wake_up(&desc->wait_for_threads);
814 }
815 
816 static void irq_thread_dtor(struct callback_head *unused)
817 {
818         struct task_struct *tsk = current;
819         struct irq_desc *desc;
820         struct irqaction *action;
821 
822         if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
823                 return;
824 
825         action = kthread_data(tsk);
826 
827         pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
828                tsk->comm, tsk->pid, action->irq);
829 
830 
831         desc = irq_to_desc(action->irq);
832         /*
833          * If IRQTF_RUNTHREAD is set, we need to decrement
834          * desc->threads_active and wake possible waiters.
835          */
836         if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
837                 wake_threads_waitq(desc);
838 
839         /* Prevent a stale desc->threads_oneshot */
840         irq_finalize_oneshot(desc, action);
841 }
842 
843 /*
844  * Interrupt handler thread
845  */
846 static int irq_thread(void *data)
847 {
848         struct callback_head on_exit_work;
849         struct irqaction *action = data;
850         struct irq_desc *desc = irq_to_desc(action->irq);
851         irqreturn_t (*handler_fn)(struct irq_desc *desc,
852                         struct irqaction *action);
853 
854         if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
855                                         &action->thread_flags))
856                 handler_fn = irq_forced_thread_fn;
857         else
858                 handler_fn = irq_thread_fn;
859 
860         init_task_work(&on_exit_work, irq_thread_dtor);
861         task_work_add(current, &on_exit_work, false);
862 
863         irq_thread_check_affinity(desc, action);
864 
865         while (!irq_wait_for_interrupt(action)) {
866                 irqreturn_t action_ret;
867 
868                 irq_thread_check_affinity(desc, action);
869 
870                 action_ret = handler_fn(desc, action);
871                 if (action_ret == IRQ_HANDLED)
872                         atomic_inc(&desc->threads_handled);
873 
874                 wake_threads_waitq(desc);
875         }
876 
877         /*
878          * This is the regular exit path. __free_irq() is stopping the
879          * thread via kthread_stop() after calling
880          * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
881          * oneshot mask bit can be set. We cannot verify that as we
882          * cannot touch the oneshot mask at this point anymore as
883          * __setup_irq() might have given out currents thread_mask
884          * again.
885          */
886         task_work_cancel(current, irq_thread_dtor);
887         return 0;
888 }
889 
890 /**
891  *      irq_wake_thread - wake the irq thread for the action identified by dev_id
892  *      @irq:           Interrupt line
893  *      @dev_id:        Device identity for which the thread should be woken
894  *
895  */
896 void irq_wake_thread(unsigned int irq, void *dev_id)
897 {
898         struct irq_desc *desc = irq_to_desc(irq);
899         struct irqaction *action;
900         unsigned long flags;
901 
902         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
903                 return;
904 
905         raw_spin_lock_irqsave(&desc->lock, flags);
906         for (action = desc->action; action; action = action->next) {
907                 if (action->dev_id == dev_id) {
908                         if (action->thread)
909                                 __irq_wake_thread(desc, action);
910                         break;
911                 }
912         }
913         raw_spin_unlock_irqrestore(&desc->lock, flags);
914 }
915 EXPORT_SYMBOL_GPL(irq_wake_thread);
916 
917 static void irq_setup_forced_threading(struct irqaction *new)
918 {
919         if (!force_irqthreads)
920                 return;
921         if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
922                 return;
923 
924         new->flags |= IRQF_ONESHOT;
925 
926         if (!new->thread_fn) {
927                 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
928                 new->thread_fn = new->handler;
929                 new->handler = irq_default_primary_handler;
930         }
931 }
932 
933 static int irq_request_resources(struct irq_desc *desc)
934 {
935         struct irq_data *d = &desc->irq_data;
936         struct irq_chip *c = d->chip;
937 
938         return c->irq_request_resources ? c->irq_request_resources(d) : 0;
939 }
940 
941 static void irq_release_resources(struct irq_desc *desc)
942 {
943         struct irq_data *d = &desc->irq_data;
944         struct irq_chip *c = d->chip;
945 
946         if (c->irq_release_resources)
947                 c->irq_release_resources(d);
948 }
949 
950 /*
951  * Internal function to register an irqaction - typically used to
952  * allocate special interrupts that are part of the architecture.
953  */
954 static int
955 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
956 {
957         struct irqaction *old, **old_ptr;
958         unsigned long flags, thread_mask = 0;
959         int ret, nested, shared = 0;
960         cpumask_var_t mask;
961 
962         if (!desc)
963                 return -EINVAL;
964 
965         if (desc->irq_data.chip == &no_irq_chip)
966                 return -ENOSYS;
967         if (!try_module_get(desc->owner))
968                 return -ENODEV;
969 
970         /*
971          * Check whether the interrupt nests into another interrupt
972          * thread.
973          */
974         nested = irq_settings_is_nested_thread(desc);
975         if (nested) {
976                 if (!new->thread_fn) {
977                         ret = -EINVAL;
978                         goto out_mput;
979                 }
980                 /*
981                  * Replace the primary handler which was provided from
982                  * the driver for non nested interrupt handling by the
983                  * dummy function which warns when called.
984                  */
985                 new->handler = irq_nested_primary_handler;
986         } else {
987                 if (irq_settings_can_thread(desc))
988                         irq_setup_forced_threading(new);
989         }
990 
991         /*
992          * Create a handler thread when a thread function is supplied
993          * and the interrupt does not nest into another interrupt
994          * thread.
995          */
996         if (new->thread_fn && !nested) {
997                 struct task_struct *t;
998                 static const struct sched_param param = {
999                         .sched_priority = MAX_USER_RT_PRIO/2,
1000                 };
1001 
1002                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
1003                                    new->name);
1004                 if (IS_ERR(t)) {
1005                         ret = PTR_ERR(t);
1006                         goto out_mput;
1007                 }
1008 
1009                 sched_setscheduler_nocheck(t, SCHED_FIFO, &param);
1010 
1011                 /*
1012                  * We keep the reference to the task struct even if
1013                  * the thread dies to avoid that the interrupt code
1014                  * references an already freed task_struct.
1015                  */
1016                 get_task_struct(t);
1017                 new->thread = t;
1018                 /*
1019                  * Tell the thread to set its affinity. This is
1020                  * important for shared interrupt handlers as we do
1021                  * not invoke setup_affinity() for the secondary
1022                  * handlers as everything is already set up. Even for
1023                  * interrupts marked with IRQF_NO_BALANCE this is
1024                  * correct as we want the thread to move to the cpu(s)
1025                  * on which the requesting code placed the interrupt.
1026                  */
1027                 set_bit(IRQTF_AFFINITY, &new->thread_flags);
1028         }
1029 
1030         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
1031                 ret = -ENOMEM;
1032                 goto out_thread;
1033         }
1034 
1035         /*
1036          * Drivers are often written to work w/o knowledge about the
1037          * underlying irq chip implementation, so a request for a
1038          * threaded irq without a primary hard irq context handler
1039          * requires the ONESHOT flag to be set. Some irq chips like
1040          * MSI based interrupts are per se one shot safe. Check the
1041          * chip flags, so we can avoid the unmask dance at the end of
1042          * the threaded handler for those.
1043          */
1044         if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
1045                 new->flags &= ~IRQF_ONESHOT;
1046 
1047         /*
1048          * The following block of code has to be executed atomically
1049          */
1050         raw_spin_lock_irqsave(&desc->lock, flags);
1051         old_ptr = &desc->action;
1052         old = *old_ptr;
1053         if (old) {
1054                 /*
1055                  * Can't share interrupts unless both agree to and are
1056                  * the same type (level, edge, polarity). So both flag
1057                  * fields must have IRQF_SHARED set and the bits which
1058                  * set the trigger type must match. Also all must
1059                  * agree on ONESHOT.
1060                  */
1061                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
1062                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
1063                     ((old->flags ^ new->flags) & IRQF_ONESHOT))
1064                         goto mismatch;
1065 
1066                 /* All handlers must agree on per-cpuness */
1067                 if ((old->flags & IRQF_PERCPU) !=
1068                     (new->flags & IRQF_PERCPU))
1069                         goto mismatch;
1070 
1071                 /* add new interrupt at end of irq queue */
1072                 do {
1073                         /*
1074                          * Or all existing action->thread_mask bits,
1075                          * so we can find the next zero bit for this
1076                          * new action.
1077                          */
1078                         thread_mask |= old->thread_mask;
1079                         old_ptr = &old->next;
1080                         old = *old_ptr;
1081                 } while (old);
1082                 shared = 1;
1083         }
1084 
1085         /*
1086          * Setup the thread mask for this irqaction for ONESHOT. For
1087          * !ONESHOT irqs the thread mask is 0 so we can avoid a
1088          * conditional in irq_wake_thread().
1089          */
1090         if (new->flags & IRQF_ONESHOT) {
1091                 /*
1092                  * Unlikely to have 32 resp 64 irqs sharing one line,
1093                  * but who knows.
1094                  */
1095                 if (thread_mask == ~0UL) {
1096                         ret = -EBUSY;
1097                         goto out_mask;
1098                 }
1099                 /*
1100                  * The thread_mask for the action is or'ed to
1101                  * desc->thread_active to indicate that the
1102                  * IRQF_ONESHOT thread handler has been woken, but not
1103                  * yet finished. The bit is cleared when a thread
1104                  * completes. When all threads of a shared interrupt
1105                  * line have completed desc->threads_active becomes
1106                  * zero and the interrupt line is unmasked. See
1107                  * handle.c:irq_wake_thread() for further information.
1108                  *
1109                  * If no thread is woken by primary (hard irq context)
1110                  * interrupt handlers, then desc->threads_active is
1111                  * also checked for zero to unmask the irq line in the
1112                  * affected hard irq flow handlers
1113                  * (handle_[fasteoi|level]_irq).
1114                  *
1115                  * The new action gets the first zero bit of
1116                  * thread_mask assigned. See the loop above which or's
1117                  * all existing action->thread_mask bits.
1118                  */
1119                 new->thread_mask = 1 << ffz(thread_mask);
1120 
1121         } else if (new->handler == irq_default_primary_handler &&
1122                    !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
1123                 /*
1124                  * The interrupt was requested with handler = NULL, so
1125                  * we use the default primary handler for it. But it
1126                  * does not have the oneshot flag set. In combination
1127                  * with level interrupts this is deadly, because the
1128                  * default primary handler just wakes the thread, then
1129                  * the irq lines is reenabled, but the device still
1130                  * has the level irq asserted. Rinse and repeat....
1131                  *
1132                  * While this works for edge type interrupts, we play
1133                  * it safe and reject unconditionally because we can't
1134                  * say for sure which type this interrupt really
1135                  * has. The type flags are unreliable as the
1136                  * underlying chip implementation can override them.
1137                  */
1138                 pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1139                        irq);
1140                 ret = -EINVAL;
1141                 goto out_mask;
1142         }
1143 
1144         if (!shared) {
1145                 ret = irq_request_resources(desc);
1146                 if (ret) {
1147                         pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
1148                                new->name, irq, desc->irq_data.chip->name);
1149                         goto out_mask;
1150                 }
1151 
1152                 init_waitqueue_head(&desc->wait_for_threads);
1153 
1154                 /* Setup the type (level, edge polarity) if configured: */
1155                 if (new->flags & IRQF_TRIGGER_MASK) {
1156                         ret = __irq_set_trigger(desc, irq,
1157                                         new->flags & IRQF_TRIGGER_MASK);
1158 
1159                         if (ret)
1160                                 goto out_mask;
1161                 }
1162 
1163                 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1164                                   IRQS_ONESHOT | IRQS_WAITING);
1165                 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1166 
1167                 if (new->flags & IRQF_PERCPU) {
1168                         irqd_set(&desc->irq_data, IRQD_PER_CPU);
1169                         irq_settings_set_per_cpu(desc);
1170                 }
1171 
1172                 if (new->flags & IRQF_ONESHOT)
1173                         desc->istate |= IRQS_ONESHOT;
1174 
1175                 if (irq_settings_can_autoenable(desc))
1176                         irq_startup(desc, true);
1177                 else
1178                         /* Undo nested disables: */
1179                         desc->depth = 1;
1180 
1181                 /* Exclude IRQ from balancing if requested */
1182                 if (new->flags & IRQF_NOBALANCING) {
1183                         irq_settings_set_no_balancing(desc);
1184                         irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1185                 }
1186 
1187                 /* Set default affinity mask once everything is setup */
1188                 setup_affinity(irq, desc, mask);
1189 
1190         } else if (new->flags & IRQF_TRIGGER_MASK) {
1191                 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1192                 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1193 
1194                 if (nmsk != omsk)
1195                         /* hope the handler works with current  trigger mode */
1196                         pr_warning("irq %d uses trigger mode %u; requested %u\n",
1197                                    irq, nmsk, omsk);
1198         }
1199 
1200         new->irq = irq;
1201         *old_ptr = new;
1202 
1203         irq_pm_install_action(desc, new);
1204 
1205         /* Reset broken irq detection when installing new handler */
1206         desc->irq_count = 0;
1207         desc->irqs_unhandled = 0;
1208 
1209         /*
1210          * Check whether we disabled the irq via the spurious handler
1211          * before. Reenable it and give it another chance.
1212          */
1213         if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1214                 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1215                 __enable_irq(desc, irq);
1216         }
1217 
1218         raw_spin_unlock_irqrestore(&desc->lock, flags);
1219 
1220         /*
1221          * Strictly no need to wake it up, but hung_task complains
1222          * when no hard interrupt wakes the thread up.
1223          */
1224         if (new->thread)
1225                 wake_up_process(new->thread);
1226 
1227         register_irq_proc(irq, desc);
1228         new->dir = NULL;
1229         register_handler_proc(irq, new);
1230         free_cpumask_var(mask);
1231 
1232         return 0;
1233 
1234 mismatch:
1235         if (!(new->flags & IRQF_PROBE_SHARED)) {
1236                 pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1237                        irq, new->flags, new->name, old->flags, old->name);
1238 #ifdef CONFIG_DEBUG_SHIRQ
1239                 dump_stack();
1240 #endif
1241         }
1242         ret = -EBUSY;
1243 
1244 out_mask:
1245         raw_spin_unlock_irqrestore(&desc->lock, flags);
1246         free_cpumask_var(mask);
1247 
1248 out_thread:
1249         if (new->thread) {
1250                 struct task_struct *t = new->thread;
1251 
1252                 new->thread = NULL;
1253                 kthread_stop(t);
1254                 put_task_struct(t);
1255         }
1256 out_mput:
1257         module_put(desc->owner);
1258         return ret;
1259 }
1260 
1261 /**
1262  *      setup_irq - setup an interrupt
1263  *      @irq: Interrupt line to setup
1264  *      @act: irqaction for the interrupt
1265  *
1266  * Used to statically setup interrupts in the early boot process.
1267  */
1268 int setup_irq(unsigned int irq, struct irqaction *act)
1269 {
1270         int retval;
1271         struct irq_desc *desc = irq_to_desc(irq);
1272 
1273         if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1274                 return -EINVAL;
1275         chip_bus_lock(desc);
1276         retval = __setup_irq(irq, desc, act);
1277         chip_bus_sync_unlock(desc);
1278 
1279         return retval;
1280 }
1281 EXPORT_SYMBOL_GPL(setup_irq);
1282 
1283 /*
1284  * Internal function to unregister an irqaction - used to free
1285  * regular and special interrupts that are part of the architecture.
1286  */
1287 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1288 {
1289         struct irq_desc *desc = irq_to_desc(irq);
1290         struct irqaction *action, **action_ptr;
1291         unsigned long flags;
1292 
1293         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1294 
1295         if (!desc)
1296                 return NULL;
1297 
1298         raw_spin_lock_irqsave(&desc->lock, flags);
1299 
1300         /*
1301          * There can be multiple actions per IRQ descriptor, find the right
1302          * one based on the dev_id:
1303          */
1304         action_ptr = &desc->action;
1305         for (;;) {
1306                 action = *action_ptr;
1307 
1308                 if (!action) {
1309                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
1310                         raw_spin_unlock_irqrestore(&desc->lock, flags);
1311 
1312                         return NULL;
1313                 }
1314 
1315                 if (action->dev_id == dev_id)
1316                         break;
1317                 action_ptr = &action->next;
1318         }
1319 
1320         /* Found it - now remove it from the list of entries: */
1321         *action_ptr = action->next;
1322 
1323         irq_pm_remove_action(desc, action);
1324 
1325         /* If this was the last handler, shut down the IRQ line: */
1326         if (!desc->action) {
1327                 irq_shutdown(desc);
1328                 irq_release_resources(desc);
1329         }
1330 
1331 #ifdef CONFIG_SMP
1332         /* make sure affinity_hint is cleaned up */
1333         if (WARN_ON_ONCE(desc->affinity_hint))
1334                 desc->affinity_hint = NULL;
1335 #endif
1336 
1337         raw_spin_unlock_irqrestore(&desc->lock, flags);
1338 
1339         unregister_handler_proc(irq, action);
1340 
1341         /* Make sure it's not being used on another CPU: */
1342         synchronize_irq(irq);
1343 
1344 #ifdef CONFIG_DEBUG_SHIRQ
1345         /*
1346          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1347          * event to happen even now it's being freed, so let's make sure that
1348          * is so by doing an extra call to the handler ....
1349          *
1350          * ( We do this after actually deregistering it, to make sure that a
1351          *   'real' IRQ doesn't run in * parallel with our fake. )
1352          */
1353         if (action->flags & IRQF_SHARED) {
1354                 local_irq_save(flags);
1355                 action->handler(irq, dev_id);
1356                 local_irq_restore(flags);
1357         }
1358 #endif
1359 
1360         if (action->thread) {
1361                 kthread_stop(action->thread);
1362                 put_task_struct(action->thread);
1363         }
1364 
1365         module_put(desc->owner);
1366         return action;
1367 }
1368 
1369 /**
1370  *      remove_irq - free an interrupt
1371  *      @irq: Interrupt line to free
1372  *      @act: irqaction for the interrupt
1373  *
1374  * Used to remove interrupts statically setup by the early boot process.
1375  */
1376 void remove_irq(unsigned int irq, struct irqaction *act)
1377 {
1378         struct irq_desc *desc = irq_to_desc(irq);
1379 
1380         if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1381             __free_irq(irq, act->dev_id);
1382 }
1383 EXPORT_SYMBOL_GPL(remove_irq);
1384 
1385 /**
1386  *      free_irq - free an interrupt allocated with request_irq
1387  *      @irq: Interrupt line to free
1388  *      @dev_id: Device identity to free
1389  *
1390  *      Remove an interrupt handler. The handler is removed and if the
1391  *      interrupt line is no longer in use by any driver it is disabled.
1392  *      On a shared IRQ the caller must ensure the interrupt is disabled
1393  *      on the card it drives before calling this function. The function
1394  *      does not return until any executing interrupts for this IRQ
1395  *      have completed.
1396  *
1397  *      This function must not be called from interrupt context.
1398  */
1399 void free_irq(unsigned int irq, void *dev_id)
1400 {
1401         struct irq_desc *desc = irq_to_desc(irq);
1402 
1403         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1404                 return;
1405 
1406 #ifdef CONFIG_SMP
1407         if (WARN_ON(desc->affinity_notify))
1408                 desc->affinity_notify = NULL;
1409 #endif
1410 
1411         chip_bus_lock(desc);
1412         kfree(__free_irq(irq, dev_id));
1413         chip_bus_sync_unlock(desc);
1414 }
1415 EXPORT_SYMBOL(free_irq);
1416 
1417 /**
1418  *      request_threaded_irq - allocate an interrupt line
1419  *      @irq: Interrupt line to allocate
1420  *      @handler: Function to be called when the IRQ occurs.
1421  *                Primary handler for threaded interrupts
1422  *                If NULL and thread_fn != NULL the default
1423  *                primary handler is installed
1424  *      @thread_fn: Function called from the irq handler thread
1425  *                  If NULL, no irq thread is created
1426  *      @irqflags: Interrupt type flags
1427  *      @devname: An ascii name for the claiming device
1428  *      @dev_id: A cookie passed back to the handler function
1429  *
1430  *      This call allocates interrupt resources and enables the
1431  *      interrupt line and IRQ handling. From the point this
1432  *      call is made your handler function may be invoked. Since
1433  *      your handler function must clear any interrupt the board
1434  *      raises, you must take care both to initialise your hardware
1435  *      and to set up the interrupt handler in the right order.
1436  *
1437  *      If you want to set up a threaded irq handler for your device
1438  *      then you need to supply @handler and @thread_fn. @handler is
1439  *      still called in hard interrupt context and has to check
1440  *      whether the interrupt originates from the device. If yes it
1441  *      needs to disable the interrupt on the device and return
1442  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1443  *      @thread_fn. This split handler design is necessary to support
1444  *      shared interrupts.
1445  *
1446  *      Dev_id must be globally unique. Normally the address of the
1447  *      device data structure is used as the cookie. Since the handler
1448  *      receives this value it makes sense to use it.
1449  *
1450  *      If your interrupt is shared you must pass a non NULL dev_id
1451  *      as this is required when freeing the interrupt.
1452  *
1453  *      Flags:
1454  *
1455  *      IRQF_SHARED             Interrupt is shared
1456  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1457  *
1458  */
1459 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1460                          irq_handler_t thread_fn, unsigned long irqflags,
1461                          const char *devname, void *dev_id)
1462 {
1463         struct irqaction *action;
1464         struct irq_desc *desc;
1465         int retval;
1466 
1467         /*
1468          * Sanity-check: shared interrupts must pass in a real dev-ID,
1469          * otherwise we'll have trouble later trying to figure out
1470          * which interrupt is which (messes up the interrupt freeing
1471          * logic etc).
1472          */
1473         if ((irqflags & IRQF_SHARED) && !dev_id)
1474                 return -EINVAL;
1475 
1476         desc = irq_to_desc(irq);
1477         if (!desc)
1478                 return -EINVAL;
1479 
1480         if (!irq_settings_can_request(desc) ||
1481             WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1482                 return -EINVAL;
1483 
1484         if (!handler) {
1485                 if (!thread_fn)
1486                         return -EINVAL;
1487                 handler = irq_default_primary_handler;
1488         }
1489 
1490         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1491         if (!action)
1492                 return -ENOMEM;
1493 
1494         action->handler = handler;
1495         action->thread_fn = thread_fn;
1496         action->flags = irqflags;
1497         action->name = devname;
1498         action->dev_id = dev_id;
1499 
1500         chip_bus_lock(desc);
1501         retval = __setup_irq(irq, desc, action);
1502         chip_bus_sync_unlock(desc);
1503 
1504         if (retval)
1505                 kfree(action);
1506 
1507 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1508         if (!retval && (irqflags & IRQF_SHARED)) {
1509                 /*
1510                  * It's a shared IRQ -- the driver ought to be prepared for it
1511                  * to happen immediately, so let's make sure....
1512                  * We disable the irq to make sure that a 'real' IRQ doesn't
1513                  * run in parallel with our fake.
1514                  */
1515                 unsigned long flags;
1516 
1517                 disable_irq(irq);
1518                 local_irq_save(flags);
1519 
1520                 handler(irq, dev_id);
1521 
1522                 local_irq_restore(flags);
1523                 enable_irq(irq);
1524         }
1525 #endif
1526         return retval;
1527 }
1528 EXPORT_SYMBOL(request_threaded_irq);
1529 
1530 /**
1531  *      request_any_context_irq - allocate an interrupt line
1532  *      @irq: Interrupt line to allocate
1533  *      @handler: Function to be called when the IRQ occurs.
1534  *                Threaded handler for threaded interrupts.
1535  *      @flags: Interrupt type flags
1536  *      @name: An ascii name for the claiming device
1537  *      @dev_id: A cookie passed back to the handler function
1538  *
1539  *      This call allocates interrupt resources and enables the
1540  *      interrupt line and IRQ handling. It selects either a
1541  *      hardirq or threaded handling method depending on the
1542  *      context.
1543  *
1544  *      On failure, it returns a negative value. On success,
1545  *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1546  */
1547 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1548                             unsigned long flags, const char *name, void *dev_id)
1549 {
1550         struct irq_desc *desc = irq_to_desc(irq);
1551         int ret;
1552 
1553         if (!desc)
1554                 return -EINVAL;
1555 
1556         if (irq_settings_is_nested_thread(desc)) {
1557                 ret = request_threaded_irq(irq, NULL, handler,
1558                                            flags, name, dev_id);
1559                 return !ret ? IRQC_IS_NESTED : ret;
1560         }
1561 
1562         ret = request_irq(irq, handler, flags, name, dev_id);
1563         return !ret ? IRQC_IS_HARDIRQ : ret;
1564 }
1565 EXPORT_SYMBOL_GPL(request_any_context_irq);
1566 
1567 void enable_percpu_irq(unsigned int irq, unsigned int type)
1568 {
1569         unsigned int cpu = smp_processor_id();
1570         unsigned long flags;
1571         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1572 
1573         if (!desc)
1574                 return;
1575 
1576         type &= IRQ_TYPE_SENSE_MASK;
1577         if (type != IRQ_TYPE_NONE) {
1578                 int ret;
1579 
1580                 ret = __irq_set_trigger(desc, irq, type);
1581 
1582                 if (ret) {
1583                         WARN(1, "failed to set type for IRQ%d\n", irq);
1584                         goto out;
1585                 }
1586         }
1587 
1588         irq_percpu_enable(desc, cpu);
1589 out:
1590         irq_put_desc_unlock(desc, flags);
1591 }
1592 EXPORT_SYMBOL_GPL(enable_percpu_irq);
1593 
1594 void disable_percpu_irq(unsigned int irq)
1595 {
1596         unsigned int cpu = smp_processor_id();
1597         unsigned long flags;
1598         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1599 
1600         if (!desc)
1601                 return;
1602 
1603         irq_percpu_disable(desc, cpu);
1604         irq_put_desc_unlock(desc, flags);
1605 }
1606 EXPORT_SYMBOL_GPL(disable_percpu_irq);
1607 
1608 /*
1609  * Internal function to unregister a percpu irqaction.
1610  */
1611 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1612 {
1613         struct irq_desc *desc = irq_to_desc(irq);
1614         struct irqaction *action;
1615         unsigned long flags;
1616 
1617         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1618 
1619         if (!desc)
1620                 return NULL;
1621 
1622         raw_spin_lock_irqsave(&desc->lock, flags);
1623 
1624         action = desc->action;
1625         if (!action || action->percpu_dev_id != dev_id) {
1626                 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1627                 goto bad;
1628         }
1629 
1630         if (!cpumask_empty(desc->percpu_enabled)) {
1631                 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1632                      irq, cpumask_first(desc->percpu_enabled));
1633                 goto bad;
1634         }
1635 
1636         /* Found it - now remove it from the list of entries: */
1637         desc->action = NULL;
1638 
1639         raw_spin_unlock_irqrestore(&desc->lock, flags);
1640 
1641         unregister_handler_proc(irq, action);
1642 
1643         module_put(desc->owner);
1644         return action;
1645 
1646 bad:
1647         raw_spin_unlock_irqrestore(&desc->lock, flags);
1648         return NULL;
1649 }
1650 
1651 /**
1652  *      remove_percpu_irq - free a per-cpu interrupt
1653  *      @irq: Interrupt line to free
1654  *      @act: irqaction for the interrupt
1655  *
1656  * Used to remove interrupts statically setup by the early boot process.
1657  */
1658 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1659 {
1660         struct irq_desc *desc = irq_to_desc(irq);
1661 
1662         if (desc && irq_settings_is_per_cpu_devid(desc))
1663             __free_percpu_irq(irq, act->percpu_dev_id);
1664 }
1665 
1666 /**
1667  *      free_percpu_irq - free an interrupt allocated with request_percpu_irq
1668  *      @irq: Interrupt line to free
1669  *      @dev_id: Device identity to free
1670  *
1671  *      Remove a percpu interrupt handler. The handler is removed, but
1672  *      the interrupt line is not disabled. This must be done on each
1673  *      CPU before calling this function. The function does not return
1674  *      until any executing interrupts for this IRQ have completed.
1675  *
1676  *      This function must not be called from interrupt context.
1677  */
1678 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1679 {
1680         struct irq_desc *desc = irq_to_desc(irq);
1681 
1682         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1683                 return;
1684 
1685         chip_bus_lock(desc);
1686         kfree(__free_percpu_irq(irq, dev_id));
1687         chip_bus_sync_unlock(desc);
1688 }
1689 
1690 /**
1691  *      setup_percpu_irq - setup a per-cpu interrupt
1692  *      @irq: Interrupt line to setup
1693  *      @act: irqaction for the interrupt
1694  *
1695  * Used to statically setup per-cpu interrupts in the early boot process.
1696  */
1697 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1698 {
1699         struct irq_desc *desc = irq_to_desc(irq);
1700         int retval;
1701 
1702         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1703                 return -EINVAL;
1704         chip_bus_lock(desc);
1705         retval = __setup_irq(irq, desc, act);
1706         chip_bus_sync_unlock(desc);
1707 
1708         return retval;
1709 }
1710 
1711 /**
1712  *      request_percpu_irq - allocate a percpu interrupt line
1713  *      @irq: Interrupt line to allocate
1714  *      @handler: Function to be called when the IRQ occurs.
1715  *      @devname: An ascii name for the claiming device
1716  *      @dev_id: A percpu cookie passed back to the handler function
1717  *
1718  *      This call allocates interrupt resources, but doesn't
1719  *      automatically enable the interrupt. It has to be done on each
1720  *      CPU using enable_percpu_irq().
1721  *
1722  *      Dev_id must be globally unique. It is a per-cpu variable, and
1723  *      the handler gets called with the interrupted CPU's instance of
1724  *      that variable.
1725  */
1726 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1727                        const char *devname, void __percpu *dev_id)
1728 {
1729         struct irqaction *action;
1730         struct irq_desc *desc;
1731         int retval;
1732 
1733         if (!dev_id)
1734                 return -EINVAL;
1735 
1736         desc = irq_to_desc(irq);
1737         if (!desc || !irq_settings_can_request(desc) ||
1738             !irq_settings_is_per_cpu_devid(desc))
1739                 return -EINVAL;
1740 
1741         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1742         if (!action)
1743                 return -ENOMEM;
1744 
1745         action->handler = handler;
1746         action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1747         action->name = devname;
1748         action->percpu_dev_id = dev_id;
1749 
1750         chip_bus_lock(desc);
1751         retval = __setup_irq(irq, desc, action);
1752         chip_bus_sync_unlock(desc);
1753 
1754         if (retval)
1755                 kfree(action);
1756 
1757         return retval;
1758 }
1759 

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