Merge branch 'for-3.5-take-2' of git://linux-nfs.org/~bfields/linux
[linux-3.10.git] / 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
20 #include "internals.h"
21
22 #ifdef CONFIG_IRQ_FORCED_THREADING
23 __read_mostly bool force_irqthreads;
24
25 static int __init setup_forced_irqthreads(char *arg)
26 {
27         force_irqthreads = true;
28         return 0;
29 }
30 early_param("threadirqs", setup_forced_irqthreads);
31 #endif
32
33 /**
34  *      synchronize_irq - wait for pending IRQ handlers (on other CPUs)
35  *      @irq: interrupt number to wait for
36  *
37  *      This function waits for any pending IRQ handlers for this interrupt
38  *      to complete before returning. If you use this function while
39  *      holding a resource the IRQ handler may need you will deadlock.
40  *
41  *      This function may be called - with care - from IRQ context.
42  */
43 void synchronize_irq(unsigned int irq)
44 {
45         struct irq_desc *desc = irq_to_desc(irq);
46         bool inprogress;
47
48         if (!desc)
49                 return;
50
51         do {
52                 unsigned long flags;
53
54                 /*
55                  * Wait until we're out of the critical section.  This might
56                  * give the wrong answer due to the lack of memory barriers.
57                  */
58                 while (irqd_irq_inprogress(&desc->irq_data))
59                         cpu_relax();
60
61                 /* Ok, that indicated we're done: double-check carefully. */
62                 raw_spin_lock_irqsave(&desc->lock, flags);
63                 inprogress = irqd_irq_inprogress(&desc->irq_data);
64                 raw_spin_unlock_irqrestore(&desc->lock, flags);
65
66                 /* Oops, that failed? */
67         } while (inprogress);
68
69         /*
70          * We made sure that no hardirq handler is running. Now verify
71          * that no threaded handlers are active.
72          */
73         wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
74 }
75 EXPORT_SYMBOL(synchronize_irq);
76
77 #ifdef CONFIG_SMP
78 cpumask_var_t irq_default_affinity;
79
80 /**
81  *      irq_can_set_affinity - Check if the affinity of a given irq can be set
82  *      @irq:           Interrupt to check
83  *
84  */
85 int irq_can_set_affinity(unsigned int irq)
86 {
87         struct irq_desc *desc = irq_to_desc(irq);
88
89         if (!desc || !irqd_can_balance(&desc->irq_data) ||
90             !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
91                 return 0;
92
93         return 1;
94 }
95
96 /**
97  *      irq_set_thread_affinity - Notify irq threads to adjust affinity
98  *      @desc:          irq descriptor which has affitnity changed
99  *
100  *      We just set IRQTF_AFFINITY and delegate the affinity setting
101  *      to the interrupt thread itself. We can not call
102  *      set_cpus_allowed_ptr() here as we hold desc->lock and this
103  *      code can be called from hard interrupt context.
104  */
105 void irq_set_thread_affinity(struct irq_desc *desc)
106 {
107         struct irqaction *action = desc->action;
108
109         while (action) {
110                 if (action->thread)
111                         set_bit(IRQTF_AFFINITY, &action->thread_flags);
112                 action = action->next;
113         }
114 }
115
116 #ifdef CONFIG_GENERIC_PENDING_IRQ
117 static inline bool irq_can_move_pcntxt(struct irq_data *data)
118 {
119         return irqd_can_move_in_process_context(data);
120 }
121 static inline bool irq_move_pending(struct irq_data *data)
122 {
123         return irqd_is_setaffinity_pending(data);
124 }
125 static inline void
126 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
127 {
128         cpumask_copy(desc->pending_mask, mask);
129 }
130 static inline void
131 irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
132 {
133         cpumask_copy(mask, desc->pending_mask);
134 }
135 #else
136 static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
137 static inline bool irq_move_pending(struct irq_data *data) { return false; }
138 static inline void
139 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
140 static inline void
141 irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
142 #endif
143
144 int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask)
145 {
146         struct irq_chip *chip = irq_data_get_irq_chip(data);
147         struct irq_desc *desc = irq_data_to_desc(data);
148         int ret = 0;
149
150         if (!chip || !chip->irq_set_affinity)
151                 return -EINVAL;
152
153         if (irq_can_move_pcntxt(data)) {
154                 ret = chip->irq_set_affinity(data, mask, false);
155                 switch (ret) {
156                 case IRQ_SET_MASK_OK:
157                         cpumask_copy(data->affinity, mask);
158                 case IRQ_SET_MASK_OK_NOCOPY:
159                         irq_set_thread_affinity(desc);
160                         ret = 0;
161                 }
162         } else {
163                 irqd_set_move_pending(data);
164                 irq_copy_pending(desc, mask);
165         }
166
167         if (desc->affinity_notify) {
168                 kref_get(&desc->affinity_notify->kref);
169                 schedule_work(&desc->affinity_notify->work);
170         }
171         irqd_set(data, IRQD_AFFINITY_SET);
172
173         return ret;
174 }
175
176 /**
177  *      irq_set_affinity - Set the irq affinity of a given irq
178  *      @irq:           Interrupt to set affinity
179  *      @mask:          cpumask
180  *
181  */
182 int irq_set_affinity(unsigned int irq, const struct cpumask *mask)
183 {
184         struct irq_desc *desc = irq_to_desc(irq);
185         unsigned long flags;
186         int ret;
187
188         if (!desc)
189                 return -EINVAL;
190
191         raw_spin_lock_irqsave(&desc->lock, flags);
192         ret =  __irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask);
193         raw_spin_unlock_irqrestore(&desc->lock, flags);
194         return ret;
195 }
196
197 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
198 {
199         unsigned long flags;
200         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
201
202         if (!desc)
203                 return -EINVAL;
204         desc->affinity_hint = m;
205         irq_put_desc_unlock(desc, flags);
206         return 0;
207 }
208 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
209
210 static void irq_affinity_notify(struct work_struct *work)
211 {
212         struct irq_affinity_notify *notify =
213                 container_of(work, struct irq_affinity_notify, work);
214         struct irq_desc *desc = irq_to_desc(notify->irq);
215         cpumask_var_t cpumask;
216         unsigned long flags;
217
218         if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
219                 goto out;
220
221         raw_spin_lock_irqsave(&desc->lock, flags);
222         if (irq_move_pending(&desc->irq_data))
223                 irq_get_pending(cpumask, desc);
224         else
225                 cpumask_copy(cpumask, desc->irq_data.affinity);
226         raw_spin_unlock_irqrestore(&desc->lock, flags);
227
228         notify->notify(notify, cpumask);
229
230         free_cpumask_var(cpumask);
231 out:
232         kref_put(&notify->kref, notify->release);
233 }
234
235 /**
236  *      irq_set_affinity_notifier - control notification of IRQ affinity changes
237  *      @irq:           Interrupt for which to enable/disable notification
238  *      @notify:        Context for notification, or %NULL to disable
239  *                      notification.  Function pointers must be initialised;
240  *                      the other fields will be initialised by this function.
241  *
242  *      Must be called in process context.  Notification may only be enabled
243  *      after the IRQ is allocated and must be disabled before the IRQ is
244  *      freed using free_irq().
245  */
246 int
247 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
248 {
249         struct irq_desc *desc = irq_to_desc(irq);
250         struct irq_affinity_notify *old_notify;
251         unsigned long flags;
252
253         /* The release function is promised process context */
254         might_sleep();
255
256         if (!desc)
257                 return -EINVAL;
258
259         /* Complete initialisation of *notify */
260         if (notify) {
261                 notify->irq = irq;
262                 kref_init(&notify->kref);
263                 INIT_WORK(&notify->work, irq_affinity_notify);
264         }
265
266         raw_spin_lock_irqsave(&desc->lock, flags);
267         old_notify = desc->affinity_notify;
268         desc->affinity_notify = notify;
269         raw_spin_unlock_irqrestore(&desc->lock, flags);
270
271         if (old_notify)
272                 kref_put(&old_notify->kref, old_notify->release);
273
274         return 0;
275 }
276 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
277
278 #ifndef CONFIG_AUTO_IRQ_AFFINITY
279 /*
280  * Generic version of the affinity autoselector.
281  */
282 static int
283 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
284 {
285         struct irq_chip *chip = irq_desc_get_chip(desc);
286         struct cpumask *set = irq_default_affinity;
287         int ret, node = desc->irq_data.node;
288
289         /* Excludes PER_CPU and NO_BALANCE interrupts */
290         if (!irq_can_set_affinity(irq))
291                 return 0;
292
293         /*
294          * Preserve an userspace affinity setup, but make sure that
295          * one of the targets is online.
296          */
297         if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
298                 if (cpumask_intersects(desc->irq_data.affinity,
299                                        cpu_online_mask))
300                         set = desc->irq_data.affinity;
301                 else
302                         irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
303         }
304
305         cpumask_and(mask, cpu_online_mask, set);
306         if (node != NUMA_NO_NODE) {
307                 const struct cpumask *nodemask = cpumask_of_node(node);
308
309                 /* make sure at least one of the cpus in nodemask is online */
310                 if (cpumask_intersects(mask, nodemask))
311                         cpumask_and(mask, mask, nodemask);
312         }
313         ret = chip->irq_set_affinity(&desc->irq_data, mask, false);
314         switch (ret) {
315         case IRQ_SET_MASK_OK:
316                 cpumask_copy(desc->irq_data.affinity, mask);
317         case IRQ_SET_MASK_OK_NOCOPY:
318                 irq_set_thread_affinity(desc);
319         }
320         return 0;
321 }
322 #else
323 static inline int
324 setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
325 {
326         return irq_select_affinity(irq);
327 }
328 #endif
329
330 /*
331  * Called when affinity is set via /proc/irq
332  */
333 int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
334 {
335         struct irq_desc *desc = irq_to_desc(irq);
336         unsigned long flags;
337         int ret;
338
339         raw_spin_lock_irqsave(&desc->lock, flags);
340         ret = setup_affinity(irq, desc, mask);
341         raw_spin_unlock_irqrestore(&desc->lock, flags);
342         return ret;
343 }
344
345 #else
346 static inline int
347 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
348 {
349         return 0;
350 }
351 #endif
352
353 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
354 {
355         if (suspend) {
356                 if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
357                         return;
358                 desc->istate |= IRQS_SUSPENDED;
359         }
360
361         if (!desc->depth++)
362                 irq_disable(desc);
363 }
364
365 static int __disable_irq_nosync(unsigned int irq)
366 {
367         unsigned long flags;
368         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
369
370         if (!desc)
371                 return -EINVAL;
372         __disable_irq(desc, irq, false);
373         irq_put_desc_busunlock(desc, flags);
374         return 0;
375 }
376
377 /**
378  *      disable_irq_nosync - disable an irq without waiting
379  *      @irq: Interrupt to disable
380  *
381  *      Disable the selected interrupt line.  Disables and Enables are
382  *      nested.
383  *      Unlike disable_irq(), this function does not ensure existing
384  *      instances of the IRQ handler have completed before returning.
385  *
386  *      This function may be called from IRQ context.
387  */
388 void disable_irq_nosync(unsigned int irq)
389 {
390         __disable_irq_nosync(irq);
391 }
392 EXPORT_SYMBOL(disable_irq_nosync);
393
394 /**
395  *      disable_irq - disable an irq and wait for completion
396  *      @irq: Interrupt to disable
397  *
398  *      Disable the selected interrupt line.  Enables and Disables are
399  *      nested.
400  *      This function waits for any pending IRQ handlers for this interrupt
401  *      to complete before returning. If you use this function while
402  *      holding a resource the IRQ handler may need you will deadlock.
403  *
404  *      This function may be called - with care - from IRQ context.
405  */
406 void disable_irq(unsigned int irq)
407 {
408         if (!__disable_irq_nosync(irq))
409                 synchronize_irq(irq);
410 }
411 EXPORT_SYMBOL(disable_irq);
412
413 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
414 {
415         if (resume) {
416                 if (!(desc->istate & IRQS_SUSPENDED)) {
417                         if (!desc->action)
418                                 return;
419                         if (!(desc->action->flags & IRQF_FORCE_RESUME))
420                                 return;
421                         /* Pretend that it got disabled ! */
422                         desc->depth++;
423                 }
424                 desc->istate &= ~IRQS_SUSPENDED;
425         }
426
427         switch (desc->depth) {
428         case 0:
429  err_out:
430                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
431                 break;
432         case 1: {
433                 if (desc->istate & IRQS_SUSPENDED)
434                         goto err_out;
435                 /* Prevent probing on this irq: */
436                 irq_settings_set_noprobe(desc);
437                 irq_enable(desc);
438                 check_irq_resend(desc, irq);
439                 /* fall-through */
440         }
441         default:
442                 desc->depth--;
443         }
444 }
445
446 /**
447  *      enable_irq - enable handling of an irq
448  *      @irq: Interrupt to enable
449  *
450  *      Undoes the effect of one call to disable_irq().  If this
451  *      matches the last disable, processing of interrupts on this
452  *      IRQ line is re-enabled.
453  *
454  *      This function may be called from IRQ context only when
455  *      desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
456  */
457 void enable_irq(unsigned int irq)
458 {
459         unsigned long flags;
460         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
461
462         if (!desc)
463                 return;
464         if (WARN(!desc->irq_data.chip,
465                  KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
466                 goto out;
467
468         __enable_irq(desc, irq, false);
469 out:
470         irq_put_desc_busunlock(desc, flags);
471 }
472 EXPORT_SYMBOL(enable_irq);
473
474 static int set_irq_wake_real(unsigned int irq, unsigned int on)
475 {
476         struct irq_desc *desc = irq_to_desc(irq);
477         int ret = -ENXIO;
478
479         if (irq_desc_get_chip(desc)->flags &  IRQCHIP_SKIP_SET_WAKE)
480                 return 0;
481
482         if (desc->irq_data.chip->irq_set_wake)
483                 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
484
485         return ret;
486 }
487
488 /**
489  *      irq_set_irq_wake - control irq power management wakeup
490  *      @irq:   interrupt to control
491  *      @on:    enable/disable power management wakeup
492  *
493  *      Enable/disable power management wakeup mode, which is
494  *      disabled by default.  Enables and disables must match,
495  *      just as they match for non-wakeup mode support.
496  *
497  *      Wakeup mode lets this IRQ wake the system from sleep
498  *      states like "suspend to RAM".
499  */
500 int irq_set_irq_wake(unsigned int irq, unsigned int on)
501 {
502         unsigned long flags;
503         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
504         int ret = 0;
505
506         if (!desc)
507                 return -EINVAL;
508
509         /* wakeup-capable irqs can be shared between drivers that
510          * don't need to have the same sleep mode behaviors.
511          */
512         if (on) {
513                 if (desc->wake_depth++ == 0) {
514                         ret = set_irq_wake_real(irq, on);
515                         if (ret)
516                                 desc->wake_depth = 0;
517                         else
518                                 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
519                 }
520         } else {
521                 if (desc->wake_depth == 0) {
522                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
523                 } else if (--desc->wake_depth == 0) {
524                         ret = set_irq_wake_real(irq, on);
525                         if (ret)
526                                 desc->wake_depth = 1;
527                         else
528                                 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
529                 }
530         }
531         irq_put_desc_busunlock(desc, flags);
532         return ret;
533 }
534 EXPORT_SYMBOL(irq_set_irq_wake);
535
536 /*
537  * Internal function that tells the architecture code whether a
538  * particular irq has been exclusively allocated or is available
539  * for driver use.
540  */
541 int can_request_irq(unsigned int irq, unsigned long irqflags)
542 {
543         unsigned long flags;
544         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
545         int canrequest = 0;
546
547         if (!desc)
548                 return 0;
549
550         if (irq_settings_can_request(desc)) {
551                 if (desc->action)
552                         if (irqflags & desc->action->flags & IRQF_SHARED)
553                                 canrequest =1;
554         }
555         irq_put_desc_unlock(desc, flags);
556         return canrequest;
557 }
558
559 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
560                       unsigned long flags)
561 {
562         struct irq_chip *chip = desc->irq_data.chip;
563         int ret, unmask = 0;
564
565         if (!chip || !chip->irq_set_type) {
566                 /*
567                  * IRQF_TRIGGER_* but the PIC does not support multiple
568                  * flow-types?
569                  */
570                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
571                          chip ? (chip->name ? : "unknown") : "unknown");
572                 return 0;
573         }
574
575         flags &= IRQ_TYPE_SENSE_MASK;
576
577         if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
578                 if (!irqd_irq_masked(&desc->irq_data))
579                         mask_irq(desc);
580                 if (!irqd_irq_disabled(&desc->irq_data))
581                         unmask = 1;
582         }
583
584         /* caller masked out all except trigger mode flags */
585         ret = chip->irq_set_type(&desc->irq_data, flags);
586
587         switch (ret) {
588         case IRQ_SET_MASK_OK:
589                 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
590                 irqd_set(&desc->irq_data, flags);
591
592         case IRQ_SET_MASK_OK_NOCOPY:
593                 flags = irqd_get_trigger_type(&desc->irq_data);
594                 irq_settings_set_trigger_mask(desc, flags);
595                 irqd_clear(&desc->irq_data, IRQD_LEVEL);
596                 irq_settings_clr_level(desc);
597                 if (flags & IRQ_TYPE_LEVEL_MASK) {
598                         irq_settings_set_level(desc);
599                         irqd_set(&desc->irq_data, IRQD_LEVEL);
600                 }
601
602                 ret = 0;
603                 break;
604         default:
605                 pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
606                        flags, irq, chip->irq_set_type);
607         }
608         if (unmask)
609                 unmask_irq(desc);
610         return ret;
611 }
612
613 /*
614  * Default primary interrupt handler for threaded interrupts. Is
615  * assigned as primary handler when request_threaded_irq is called
616  * with handler == NULL. Useful for oneshot interrupts.
617  */
618 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
619 {
620         return IRQ_WAKE_THREAD;
621 }
622
623 /*
624  * Primary handler for nested threaded interrupts. Should never be
625  * called.
626  */
627 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
628 {
629         WARN(1, "Primary handler called for nested irq %d\n", irq);
630         return IRQ_NONE;
631 }
632
633 static int irq_wait_for_interrupt(struct irqaction *action)
634 {
635         set_current_state(TASK_INTERRUPTIBLE);
636
637         while (!kthread_should_stop()) {
638
639                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
640                                        &action->thread_flags)) {
641                         __set_current_state(TASK_RUNNING);
642                         return 0;
643                 }
644                 schedule();
645                 set_current_state(TASK_INTERRUPTIBLE);
646         }
647         __set_current_state(TASK_RUNNING);
648         return -1;
649 }
650
651 /*
652  * Oneshot interrupts keep the irq line masked until the threaded
653  * handler finished. unmask if the interrupt has not been disabled and
654  * is marked MASKED.
655  */
656 static void irq_finalize_oneshot(struct irq_desc *desc,
657                                  struct irqaction *action)
658 {
659         if (!(desc->istate & IRQS_ONESHOT))
660                 return;
661 again:
662         chip_bus_lock(desc);
663         raw_spin_lock_irq(&desc->lock);
664
665         /*
666          * Implausible though it may be we need to protect us against
667          * the following scenario:
668          *
669          * The thread is faster done than the hard interrupt handler
670          * on the other CPU. If we unmask the irq line then the
671          * interrupt can come in again and masks the line, leaves due
672          * to IRQS_INPROGRESS and the irq line is masked forever.
673          *
674          * This also serializes the state of shared oneshot handlers
675          * versus "desc->threads_onehsot |= action->thread_mask;" in
676          * irq_wake_thread(). See the comment there which explains the
677          * serialization.
678          */
679         if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
680                 raw_spin_unlock_irq(&desc->lock);
681                 chip_bus_sync_unlock(desc);
682                 cpu_relax();
683                 goto again;
684         }
685
686         /*
687          * Now check again, whether the thread should run. Otherwise
688          * we would clear the threads_oneshot bit of this thread which
689          * was just set.
690          */
691         if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
692                 goto out_unlock;
693
694         desc->threads_oneshot &= ~action->thread_mask;
695
696         if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
697             irqd_irq_masked(&desc->irq_data))
698                 unmask_irq(desc);
699
700 out_unlock:
701         raw_spin_unlock_irq(&desc->lock);
702         chip_bus_sync_unlock(desc);
703 }
704
705 #ifdef CONFIG_SMP
706 /*
707  * Check whether we need to chasnge the affinity of the interrupt thread.
708  */
709 static void
710 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
711 {
712         cpumask_var_t mask;
713
714         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
715                 return;
716
717         /*
718          * In case we are out of memory we set IRQTF_AFFINITY again and
719          * try again next time
720          */
721         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
722                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
723                 return;
724         }
725
726         raw_spin_lock_irq(&desc->lock);
727         cpumask_copy(mask, desc->irq_data.affinity);
728         raw_spin_unlock_irq(&desc->lock);
729
730         set_cpus_allowed_ptr(current, mask);
731         free_cpumask_var(mask);
732 }
733 #else
734 static inline void
735 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
736 #endif
737
738 /*
739  * Interrupts which are not explicitely requested as threaded
740  * interrupts rely on the implicit bh/preempt disable of the hard irq
741  * context. So we need to disable bh here to avoid deadlocks and other
742  * side effects.
743  */
744 static irqreturn_t
745 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
746 {
747         irqreturn_t ret;
748
749         local_bh_disable();
750         ret = action->thread_fn(action->irq, action->dev_id);
751         irq_finalize_oneshot(desc, action);
752         local_bh_enable();
753         return ret;
754 }
755
756 /*
757  * Interrupts explicitely requested as threaded interupts want to be
758  * preemtible - many of them need to sleep and wait for slow busses to
759  * complete.
760  */
761 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
762                 struct irqaction *action)
763 {
764         irqreturn_t ret;
765
766         ret = action->thread_fn(action->irq, action->dev_id);
767         irq_finalize_oneshot(desc, action);
768         return ret;
769 }
770
771 static void wake_threads_waitq(struct irq_desc *desc)
772 {
773         if (atomic_dec_and_test(&desc->threads_active) &&
774             waitqueue_active(&desc->wait_for_threads))
775                 wake_up(&desc->wait_for_threads);
776 }
777
778 /*
779  * Interrupt handler thread
780  */
781 static int irq_thread(void *data)
782 {
783         static const struct sched_param param = {
784                 .sched_priority = MAX_USER_RT_PRIO/2,
785         };
786         struct irqaction *action = data;
787         struct irq_desc *desc = irq_to_desc(action->irq);
788         irqreturn_t (*handler_fn)(struct irq_desc *desc,
789                         struct irqaction *action);
790
791         if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
792                                         &action->thread_flags))
793                 handler_fn = irq_forced_thread_fn;
794         else
795                 handler_fn = irq_thread_fn;
796
797         sched_setscheduler(current, SCHED_FIFO, &param);
798         current->irq_thread = 1;
799
800         while (!irq_wait_for_interrupt(action)) {
801                 irqreturn_t action_ret;
802
803                 irq_thread_check_affinity(desc, action);
804
805                 action_ret = handler_fn(desc, action);
806                 if (!noirqdebug)
807                         note_interrupt(action->irq, desc, action_ret);
808
809                 wake_threads_waitq(desc);
810         }
811
812         /*
813          * This is the regular exit path. __free_irq() is stopping the
814          * thread via kthread_stop() after calling
815          * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
816          * oneshot mask bit can be set. We cannot verify that as we
817          * cannot touch the oneshot mask at this point anymore as
818          * __setup_irq() might have given out currents thread_mask
819          * again.
820          *
821          * Clear irq_thread. Otherwise exit_irq_thread() would make
822          * fuzz about an active irq thread going into nirvana.
823          */
824         current->irq_thread = 0;
825         return 0;
826 }
827
828 /*
829  * Called from do_exit()
830  */
831 void exit_irq_thread(void)
832 {
833         struct task_struct *tsk = current;
834         struct irq_desc *desc;
835         struct irqaction *action;
836
837         if (!tsk->irq_thread)
838                 return;
839
840         action = kthread_data(tsk);
841
842         pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
843                tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
844
845         desc = irq_to_desc(action->irq);
846
847         /*
848          * If IRQTF_RUNTHREAD is set, we need to decrement
849          * desc->threads_active and wake possible waiters.
850          */
851         if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
852                 wake_threads_waitq(desc);
853
854         /* Prevent a stale desc->threads_oneshot */
855         irq_finalize_oneshot(desc, action);
856 }
857
858 static void irq_setup_forced_threading(struct irqaction *new)
859 {
860         if (!force_irqthreads)
861                 return;
862         if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
863                 return;
864
865         new->flags |= IRQF_ONESHOT;
866
867         if (!new->thread_fn) {
868                 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
869                 new->thread_fn = new->handler;
870                 new->handler = irq_default_primary_handler;
871         }
872 }
873
874 /*
875  * Internal function to register an irqaction - typically used to
876  * allocate special interrupts that are part of the architecture.
877  */
878 static int
879 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
880 {
881         struct irqaction *old, **old_ptr;
882         unsigned long flags, thread_mask = 0;
883         int ret, nested, shared = 0;
884         cpumask_var_t mask;
885
886         if (!desc)
887                 return -EINVAL;
888
889         if (desc->irq_data.chip == &no_irq_chip)
890                 return -ENOSYS;
891         if (!try_module_get(desc->owner))
892                 return -ENODEV;
893         /*
894          * Some drivers like serial.c use request_irq() heavily,
895          * so we have to be careful not to interfere with a
896          * running system.
897          */
898         if (new->flags & IRQF_SAMPLE_RANDOM) {
899                 /*
900                  * This function might sleep, we want to call it first,
901                  * outside of the atomic block.
902                  * Yes, this might clear the entropy pool if the wrong
903                  * driver is attempted to be loaded, without actually
904                  * installing a new handler, but is this really a problem,
905                  * only the sysadmin is able to do this.
906                  */
907                 rand_initialize_irq(irq);
908         }
909
910         /*
911          * Check whether the interrupt nests into another interrupt
912          * thread.
913          */
914         nested = irq_settings_is_nested_thread(desc);
915         if (nested) {
916                 if (!new->thread_fn) {
917                         ret = -EINVAL;
918                         goto out_mput;
919                 }
920                 /*
921                  * Replace the primary handler which was provided from
922                  * the driver for non nested interrupt handling by the
923                  * dummy function which warns when called.
924                  */
925                 new->handler = irq_nested_primary_handler;
926         } else {
927                 if (irq_settings_can_thread(desc))
928                         irq_setup_forced_threading(new);
929         }
930
931         /*
932          * Create a handler thread when a thread function is supplied
933          * and the interrupt does not nest into another interrupt
934          * thread.
935          */
936         if (new->thread_fn && !nested) {
937                 struct task_struct *t;
938
939                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
940                                    new->name);
941                 if (IS_ERR(t)) {
942                         ret = PTR_ERR(t);
943                         goto out_mput;
944                 }
945                 /*
946                  * We keep the reference to the task struct even if
947                  * the thread dies to avoid that the interrupt code
948                  * references an already freed task_struct.
949                  */
950                 get_task_struct(t);
951                 new->thread = t;
952         }
953
954         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
955                 ret = -ENOMEM;
956                 goto out_thread;
957         }
958
959         /*
960          * The following block of code has to be executed atomically
961          */
962         raw_spin_lock_irqsave(&desc->lock, flags);
963         old_ptr = &desc->action;
964         old = *old_ptr;
965         if (old) {
966                 /*
967                  * Can't share interrupts unless both agree to and are
968                  * the same type (level, edge, polarity). So both flag
969                  * fields must have IRQF_SHARED set and the bits which
970                  * set the trigger type must match. Also all must
971                  * agree on ONESHOT.
972                  */
973                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
974                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
975                     ((old->flags ^ new->flags) & IRQF_ONESHOT))
976                         goto mismatch;
977
978                 /* All handlers must agree on per-cpuness */
979                 if ((old->flags & IRQF_PERCPU) !=
980                     (new->flags & IRQF_PERCPU))
981                         goto mismatch;
982
983                 /* add new interrupt at end of irq queue */
984                 do {
985                         /*
986                          * Or all existing action->thread_mask bits,
987                          * so we can find the next zero bit for this
988                          * new action.
989                          */
990                         thread_mask |= old->thread_mask;
991                         old_ptr = &old->next;
992                         old = *old_ptr;
993                 } while (old);
994                 shared = 1;
995         }
996
997         /*
998          * Setup the thread mask for this irqaction for ONESHOT. For
999          * !ONESHOT irqs the thread mask is 0 so we can avoid a
1000          * conditional in irq_wake_thread().
1001          */
1002         if (new->flags & IRQF_ONESHOT) {
1003                 /*
1004                  * Unlikely to have 32 resp 64 irqs sharing one line,
1005                  * but who knows.
1006                  */
1007                 if (thread_mask == ~0UL) {
1008                         ret = -EBUSY;
1009                         goto out_mask;
1010                 }
1011                 /*
1012                  * The thread_mask for the action is or'ed to
1013                  * desc->thread_active to indicate that the
1014                  * IRQF_ONESHOT thread handler has been woken, but not
1015                  * yet finished. The bit is cleared when a thread
1016                  * completes. When all threads of a shared interrupt
1017                  * line have completed desc->threads_active becomes
1018                  * zero and the interrupt line is unmasked. See
1019                  * handle.c:irq_wake_thread() for further information.
1020                  *
1021                  * If no thread is woken by primary (hard irq context)
1022                  * interrupt handlers, then desc->threads_active is
1023                  * also checked for zero to unmask the irq line in the
1024                  * affected hard irq flow handlers
1025                  * (handle_[fasteoi|level]_irq).
1026                  *
1027                  * The new action gets the first zero bit of
1028                  * thread_mask assigned. See the loop above which or's
1029                  * all existing action->thread_mask bits.
1030                  */
1031                 new->thread_mask = 1 << ffz(thread_mask);
1032
1033         } else if (new->handler == irq_default_primary_handler) {
1034                 /*
1035                  * The interrupt was requested with handler = NULL, so
1036                  * we use the default primary handler for it. But it
1037                  * does not have the oneshot flag set. In combination
1038                  * with level interrupts this is deadly, because the
1039                  * default primary handler just wakes the thread, then
1040                  * the irq lines is reenabled, but the device still
1041                  * has the level irq asserted. Rinse and repeat....
1042                  *
1043                  * While this works for edge type interrupts, we play
1044                  * it safe and reject unconditionally because we can't
1045                  * say for sure which type this interrupt really
1046                  * has. The type flags are unreliable as the
1047                  * underlying chip implementation can override them.
1048                  */
1049                 pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1050                        irq);
1051                 ret = -EINVAL;
1052                 goto out_mask;
1053         }
1054
1055         if (!shared) {
1056                 init_waitqueue_head(&desc->wait_for_threads);
1057
1058                 /* Setup the type (level, edge polarity) if configured: */
1059                 if (new->flags & IRQF_TRIGGER_MASK) {
1060                         ret = __irq_set_trigger(desc, irq,
1061                                         new->flags & IRQF_TRIGGER_MASK);
1062
1063                         if (ret)
1064                                 goto out_mask;
1065                 }
1066
1067                 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1068                                   IRQS_ONESHOT | IRQS_WAITING);
1069                 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1070
1071                 if (new->flags & IRQF_PERCPU) {
1072                         irqd_set(&desc->irq_data, IRQD_PER_CPU);
1073                         irq_settings_set_per_cpu(desc);
1074                 }
1075
1076                 if (new->flags & IRQF_ONESHOT)
1077                         desc->istate |= IRQS_ONESHOT;
1078
1079                 if (irq_settings_can_autoenable(desc))
1080                         irq_startup(desc, true);
1081                 else
1082                         /* Undo nested disables: */
1083                         desc->depth = 1;
1084
1085                 /* Exclude IRQ from balancing if requested */
1086                 if (new->flags & IRQF_NOBALANCING) {
1087                         irq_settings_set_no_balancing(desc);
1088                         irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1089                 }
1090
1091                 /* Set default affinity mask once everything is setup */
1092                 setup_affinity(irq, desc, mask);
1093
1094         } else if (new->flags & IRQF_TRIGGER_MASK) {
1095                 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1096                 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1097
1098                 if (nmsk != omsk)
1099                         /* hope the handler works with current  trigger mode */
1100                         pr_warning("irq %d uses trigger mode %u; requested %u\n",
1101                                    irq, nmsk, omsk);
1102         }
1103
1104         new->irq = irq;
1105         *old_ptr = new;
1106
1107         /* Reset broken irq detection when installing new handler */
1108         desc->irq_count = 0;
1109         desc->irqs_unhandled = 0;
1110
1111         /*
1112          * Check whether we disabled the irq via the spurious handler
1113          * before. Reenable it and give it another chance.
1114          */
1115         if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1116                 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1117                 __enable_irq(desc, irq, false);
1118         }
1119
1120         raw_spin_unlock_irqrestore(&desc->lock, flags);
1121
1122         /*
1123          * Strictly no need to wake it up, but hung_task complains
1124          * when no hard interrupt wakes the thread up.
1125          */
1126         if (new->thread)
1127                 wake_up_process(new->thread);
1128
1129         register_irq_proc(irq, desc);
1130         new->dir = NULL;
1131         register_handler_proc(irq, new);
1132         free_cpumask_var(mask);
1133
1134         return 0;
1135
1136 mismatch:
1137         if (!(new->flags & IRQF_PROBE_SHARED)) {
1138                 pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1139                        irq, new->flags, new->name, old->flags, old->name);
1140 #ifdef CONFIG_DEBUG_SHIRQ
1141                 dump_stack();
1142 #endif
1143         }
1144         ret = -EBUSY;
1145
1146 out_mask:
1147         raw_spin_unlock_irqrestore(&desc->lock, flags);
1148         free_cpumask_var(mask);
1149
1150 out_thread:
1151         if (new->thread) {
1152                 struct task_struct *t = new->thread;
1153
1154                 new->thread = NULL;
1155                 kthread_stop(t);
1156                 put_task_struct(t);
1157         }
1158 out_mput:
1159         module_put(desc->owner);
1160         return ret;
1161 }
1162
1163 /**
1164  *      setup_irq - setup an interrupt
1165  *      @irq: Interrupt line to setup
1166  *      @act: irqaction for the interrupt
1167  *
1168  * Used to statically setup interrupts in the early boot process.
1169  */
1170 int setup_irq(unsigned int irq, struct irqaction *act)
1171 {
1172         int retval;
1173         struct irq_desc *desc = irq_to_desc(irq);
1174
1175         if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1176                 return -EINVAL;
1177         chip_bus_lock(desc);
1178         retval = __setup_irq(irq, desc, act);
1179         chip_bus_sync_unlock(desc);
1180
1181         return retval;
1182 }
1183 EXPORT_SYMBOL_GPL(setup_irq);
1184
1185 /*
1186  * Internal function to unregister an irqaction - used to free
1187  * regular and special interrupts that are part of the architecture.
1188  */
1189 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1190 {
1191         struct irq_desc *desc = irq_to_desc(irq);
1192         struct irqaction *action, **action_ptr;
1193         unsigned long flags;
1194
1195         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1196
1197         if (!desc)
1198                 return NULL;
1199
1200         raw_spin_lock_irqsave(&desc->lock, flags);
1201
1202         /*
1203          * There can be multiple actions per IRQ descriptor, find the right
1204          * one based on the dev_id:
1205          */
1206         action_ptr = &desc->action;
1207         for (;;) {
1208                 action = *action_ptr;
1209
1210                 if (!action) {
1211                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
1212                         raw_spin_unlock_irqrestore(&desc->lock, flags);
1213
1214                         return NULL;
1215                 }
1216
1217                 if (action->dev_id == dev_id)
1218                         break;
1219                 action_ptr = &action->next;
1220         }
1221
1222         /* Found it - now remove it from the list of entries: */
1223         *action_ptr = action->next;
1224
1225         /* If this was the last handler, shut down the IRQ line: */
1226         if (!desc->action)
1227                 irq_shutdown(desc);
1228
1229 #ifdef CONFIG_SMP
1230         /* make sure affinity_hint is cleaned up */
1231         if (WARN_ON_ONCE(desc->affinity_hint))
1232                 desc->affinity_hint = NULL;
1233 #endif
1234
1235         raw_spin_unlock_irqrestore(&desc->lock, flags);
1236
1237         unregister_handler_proc(irq, action);
1238
1239         /* Make sure it's not being used on another CPU: */
1240         synchronize_irq(irq);
1241
1242 #ifdef CONFIG_DEBUG_SHIRQ
1243         /*
1244          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1245          * event to happen even now it's being freed, so let's make sure that
1246          * is so by doing an extra call to the handler ....
1247          *
1248          * ( We do this after actually deregistering it, to make sure that a
1249          *   'real' IRQ doesn't run in * parallel with our fake. )
1250          */
1251         if (action->flags & IRQF_SHARED) {
1252                 local_irq_save(flags);
1253                 action->handler(irq, dev_id);
1254                 local_irq_restore(flags);
1255         }
1256 #endif
1257
1258         if (action->thread) {
1259                 kthread_stop(action->thread);
1260                 put_task_struct(action->thread);
1261         }
1262
1263         module_put(desc->owner);
1264         return action;
1265 }
1266
1267 /**
1268  *      remove_irq - free an interrupt
1269  *      @irq: Interrupt line to free
1270  *      @act: irqaction for the interrupt
1271  *
1272  * Used to remove interrupts statically setup by the early boot process.
1273  */
1274 void remove_irq(unsigned int irq, struct irqaction *act)
1275 {
1276         struct irq_desc *desc = irq_to_desc(irq);
1277
1278         if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1279             __free_irq(irq, act->dev_id);
1280 }
1281 EXPORT_SYMBOL_GPL(remove_irq);
1282
1283 /**
1284  *      free_irq - free an interrupt allocated with request_irq
1285  *      @irq: Interrupt line to free
1286  *      @dev_id: Device identity to free
1287  *
1288  *      Remove an interrupt handler. The handler is removed and if the
1289  *      interrupt line is no longer in use by any driver it is disabled.
1290  *      On a shared IRQ the caller must ensure the interrupt is disabled
1291  *      on the card it drives before calling this function. The function
1292  *      does not return until any executing interrupts for this IRQ
1293  *      have completed.
1294  *
1295  *      This function must not be called from interrupt context.
1296  */
1297 void free_irq(unsigned int irq, void *dev_id)
1298 {
1299         struct irq_desc *desc = irq_to_desc(irq);
1300
1301         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1302                 return;
1303
1304 #ifdef CONFIG_SMP
1305         if (WARN_ON(desc->affinity_notify))
1306                 desc->affinity_notify = NULL;
1307 #endif
1308
1309         chip_bus_lock(desc);
1310         kfree(__free_irq(irq, dev_id));
1311         chip_bus_sync_unlock(desc);
1312 }
1313 EXPORT_SYMBOL(free_irq);
1314
1315 /**
1316  *      request_threaded_irq - allocate an interrupt line
1317  *      @irq: Interrupt line to allocate
1318  *      @handler: Function to be called when the IRQ occurs.
1319  *                Primary handler for threaded interrupts
1320  *                If NULL and thread_fn != NULL the default
1321  *                primary handler is installed
1322  *      @thread_fn: Function called from the irq handler thread
1323  *                  If NULL, no irq thread is created
1324  *      @irqflags: Interrupt type flags
1325  *      @devname: An ascii name for the claiming device
1326  *      @dev_id: A cookie passed back to the handler function
1327  *
1328  *      This call allocates interrupt resources and enables the
1329  *      interrupt line and IRQ handling. From the point this
1330  *      call is made your handler function may be invoked. Since
1331  *      your handler function must clear any interrupt the board
1332  *      raises, you must take care both to initialise your hardware
1333  *      and to set up the interrupt handler in the right order.
1334  *
1335  *      If you want to set up a threaded irq handler for your device
1336  *      then you need to supply @handler and @thread_fn. @handler is
1337  *      still called in hard interrupt context and has to check
1338  *      whether the interrupt originates from the device. If yes it
1339  *      needs to disable the interrupt on the device and return
1340  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1341  *      @thread_fn. This split handler design is necessary to support
1342  *      shared interrupts.
1343  *
1344  *      Dev_id must be globally unique. Normally the address of the
1345  *      device data structure is used as the cookie. Since the handler
1346  *      receives this value it makes sense to use it.
1347  *
1348  *      If your interrupt is shared you must pass a non NULL dev_id
1349  *      as this is required when freeing the interrupt.
1350  *
1351  *      Flags:
1352  *
1353  *      IRQF_SHARED             Interrupt is shared
1354  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
1355  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1356  *
1357  */
1358 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1359                          irq_handler_t thread_fn, unsigned long irqflags,
1360                          const char *devname, void *dev_id)
1361 {
1362         struct irqaction *action;
1363         struct irq_desc *desc;
1364         int retval;
1365
1366         /*
1367          * Sanity-check: shared interrupts must pass in a real dev-ID,
1368          * otherwise we'll have trouble later trying to figure out
1369          * which interrupt is which (messes up the interrupt freeing
1370          * logic etc).
1371          */
1372         if ((irqflags & IRQF_SHARED) && !dev_id)
1373                 return -EINVAL;
1374
1375         desc = irq_to_desc(irq);
1376         if (!desc)
1377                 return -EINVAL;
1378
1379         if (!irq_settings_can_request(desc) ||
1380             WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1381                 return -EINVAL;
1382
1383         if (!handler) {
1384                 if (!thread_fn)
1385                         return -EINVAL;
1386                 handler = irq_default_primary_handler;
1387         }
1388
1389         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1390         if (!action)
1391                 return -ENOMEM;
1392
1393         action->handler = handler;
1394         action->thread_fn = thread_fn;
1395         action->flags = irqflags;
1396         action->name = devname;
1397         action->dev_id = dev_id;
1398
1399         chip_bus_lock(desc);
1400         retval = __setup_irq(irq, desc, action);
1401         chip_bus_sync_unlock(desc);
1402
1403         if (retval)
1404                 kfree(action);
1405
1406 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1407         if (!retval && (irqflags & IRQF_SHARED)) {
1408                 /*
1409                  * It's a shared IRQ -- the driver ought to be prepared for it
1410                  * to happen immediately, so let's make sure....
1411                  * We disable the irq to make sure that a 'real' IRQ doesn't
1412                  * run in parallel with our fake.
1413                  */
1414                 unsigned long flags;
1415
1416                 disable_irq(irq);
1417                 local_irq_save(flags);
1418
1419                 handler(irq, dev_id);
1420
1421                 local_irq_restore(flags);
1422                 enable_irq(irq);
1423         }
1424 #endif
1425         return retval;
1426 }
1427 EXPORT_SYMBOL(request_threaded_irq);
1428
1429 /**
1430  *      request_any_context_irq - allocate an interrupt line
1431  *      @irq: Interrupt line to allocate
1432  *      @handler: Function to be called when the IRQ occurs.
1433  *                Threaded handler for threaded interrupts.
1434  *      @flags: Interrupt type flags
1435  *      @name: An ascii name for the claiming device
1436  *      @dev_id: A cookie passed back to the handler function
1437  *
1438  *      This call allocates interrupt resources and enables the
1439  *      interrupt line and IRQ handling. It selects either a
1440  *      hardirq or threaded handling method depending on the
1441  *      context.
1442  *
1443  *      On failure, it returns a negative value. On success,
1444  *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1445  */
1446 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1447                             unsigned long flags, const char *name, void *dev_id)
1448 {
1449         struct irq_desc *desc = irq_to_desc(irq);
1450         int ret;
1451
1452         if (!desc)
1453                 return -EINVAL;
1454
1455         if (irq_settings_is_nested_thread(desc)) {
1456                 ret = request_threaded_irq(irq, NULL, handler,
1457                                            flags, name, dev_id);
1458                 return !ret ? IRQC_IS_NESTED : ret;
1459         }
1460
1461         ret = request_irq(irq, handler, flags, name, dev_id);
1462         return !ret ? IRQC_IS_HARDIRQ : ret;
1463 }
1464 EXPORT_SYMBOL_GPL(request_any_context_irq);
1465
1466 void enable_percpu_irq(unsigned int irq, unsigned int type)
1467 {
1468         unsigned int cpu = smp_processor_id();
1469         unsigned long flags;
1470         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1471
1472         if (!desc)
1473                 return;
1474
1475         type &= IRQ_TYPE_SENSE_MASK;
1476         if (type != IRQ_TYPE_NONE) {
1477                 int ret;
1478
1479                 ret = __irq_set_trigger(desc, irq, type);
1480
1481                 if (ret) {
1482                         WARN(1, "failed to set type for IRQ%d\n", irq);
1483                         goto out;
1484                 }
1485         }
1486
1487         irq_percpu_enable(desc, cpu);
1488 out:
1489         irq_put_desc_unlock(desc, flags);
1490 }
1491
1492 void disable_percpu_irq(unsigned int irq)
1493 {
1494         unsigned int cpu = smp_processor_id();
1495         unsigned long flags;
1496         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1497
1498         if (!desc)
1499                 return;
1500
1501         irq_percpu_disable(desc, cpu);
1502         irq_put_desc_unlock(desc, flags);
1503 }
1504
1505 /*
1506  * Internal function to unregister a percpu irqaction.
1507  */
1508 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1509 {
1510         struct irq_desc *desc = irq_to_desc(irq);
1511         struct irqaction *action;
1512         unsigned long flags;
1513
1514         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1515
1516         if (!desc)
1517                 return NULL;
1518
1519         raw_spin_lock_irqsave(&desc->lock, flags);
1520
1521         action = desc->action;
1522         if (!action || action->percpu_dev_id != dev_id) {
1523                 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1524                 goto bad;
1525         }
1526
1527         if (!cpumask_empty(desc->percpu_enabled)) {
1528                 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1529                      irq, cpumask_first(desc->percpu_enabled));
1530                 goto bad;
1531         }
1532
1533         /* Found it - now remove it from the list of entries: */
1534         desc->action = NULL;
1535
1536         raw_spin_unlock_irqrestore(&desc->lock, flags);
1537
1538         unregister_handler_proc(irq, action);
1539
1540         module_put(desc->owner);
1541         return action;
1542
1543 bad:
1544         raw_spin_unlock_irqrestore(&desc->lock, flags);
1545         return NULL;
1546 }
1547
1548 /**
1549  *      remove_percpu_irq - free a per-cpu interrupt
1550  *      @irq: Interrupt line to free
1551  *      @act: irqaction for the interrupt
1552  *
1553  * Used to remove interrupts statically setup by the early boot process.
1554  */
1555 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1556 {
1557         struct irq_desc *desc = irq_to_desc(irq);
1558
1559         if (desc && irq_settings_is_per_cpu_devid(desc))
1560             __free_percpu_irq(irq, act->percpu_dev_id);
1561 }
1562
1563 /**
1564  *      free_percpu_irq - free an interrupt allocated with request_percpu_irq
1565  *      @irq: Interrupt line to free
1566  *      @dev_id: Device identity to free
1567  *
1568  *      Remove a percpu interrupt handler. The handler is removed, but
1569  *      the interrupt line is not disabled. This must be done on each
1570  *      CPU before calling this function. The function does not return
1571  *      until any executing interrupts for this IRQ have completed.
1572  *
1573  *      This function must not be called from interrupt context.
1574  */
1575 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1576 {
1577         struct irq_desc *desc = irq_to_desc(irq);
1578
1579         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1580                 return;
1581
1582         chip_bus_lock(desc);
1583         kfree(__free_percpu_irq(irq, dev_id));
1584         chip_bus_sync_unlock(desc);
1585 }
1586
1587 /**
1588  *      setup_percpu_irq - setup a per-cpu interrupt
1589  *      @irq: Interrupt line to setup
1590  *      @act: irqaction for the interrupt
1591  *
1592  * Used to statically setup per-cpu interrupts in the early boot process.
1593  */
1594 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1595 {
1596         struct irq_desc *desc = irq_to_desc(irq);
1597         int retval;
1598
1599         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1600                 return -EINVAL;
1601         chip_bus_lock(desc);
1602         retval = __setup_irq(irq, desc, act);
1603         chip_bus_sync_unlock(desc);
1604
1605         return retval;
1606 }
1607
1608 /**
1609  *      request_percpu_irq - allocate a percpu interrupt line
1610  *      @irq: Interrupt line to allocate
1611  *      @handler: Function to be called when the IRQ occurs.
1612  *      @devname: An ascii name for the claiming device
1613  *      @dev_id: A percpu cookie passed back to the handler function
1614  *
1615  *      This call allocates interrupt resources, but doesn't
1616  *      automatically enable the interrupt. It has to be done on each
1617  *      CPU using enable_percpu_irq().
1618  *
1619  *      Dev_id must be globally unique. It is a per-cpu variable, and
1620  *      the handler gets called with the interrupted CPU's instance of
1621  *      that variable.
1622  */
1623 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1624                        const char *devname, void __percpu *dev_id)
1625 {
1626         struct irqaction *action;
1627         struct irq_desc *desc;
1628         int retval;
1629
1630         if (!dev_id)
1631                 return -EINVAL;
1632
1633         desc = irq_to_desc(irq);
1634         if (!desc || !irq_settings_can_request(desc) ||
1635             !irq_settings_is_per_cpu_devid(desc))
1636                 return -EINVAL;
1637
1638         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1639         if (!action)
1640                 return -ENOMEM;
1641
1642         action->handler = handler;
1643         action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1644         action->name = devname;
1645         action->percpu_dev_id = dev_id;
1646
1647         chip_bus_lock(desc);
1648         retval = __setup_irq(irq, desc, action);
1649         chip_bus_sync_unlock(desc);
1650
1651         if (retval)
1652                 kfree(action);
1653
1654         return retval;
1655 }