Merge branch 'linus' into irq/threaded
[linux-2.6.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 #include <linux/irq.h>
11 #include <linux/kthread.h>
12 #include <linux/module.h>
13 #include <linux/random.h>
14 #include <linux/interrupt.h>
15 #include <linux/slab.h>
16 #include <linux/sched.h>
17
18 #include "internals.h"
19
20 /**
21  *      synchronize_irq - wait for pending IRQ handlers (on other CPUs)
22  *      @irq: interrupt number to wait for
23  *
24  *      This function waits for any pending IRQ handlers for this interrupt
25  *      to complete before returning. If you use this function while
26  *      holding a resource the IRQ handler may need you will deadlock.
27  *
28  *      This function may be called - with care - from IRQ context.
29  */
30 void synchronize_irq(unsigned int irq)
31 {
32         struct irq_desc *desc = irq_to_desc(irq);
33         unsigned int status;
34
35         if (!desc)
36                 return;
37
38         do {
39                 unsigned long flags;
40
41                 /*
42                  * Wait until we're out of the critical section.  This might
43                  * give the wrong answer due to the lack of memory barriers.
44                  */
45                 while (desc->status & IRQ_INPROGRESS)
46                         cpu_relax();
47
48                 /* Ok, that indicated we're done: double-check carefully. */
49                 spin_lock_irqsave(&desc->lock, flags);
50                 status = desc->status;
51                 spin_unlock_irqrestore(&desc->lock, flags);
52
53                 /* Oops, that failed? */
54         } while (status & IRQ_INPROGRESS);
55
56         /*
57          * We made sure that no hardirq handler is running. Now verify
58          * that no threaded handlers are active.
59          */
60         wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
61 }
62 EXPORT_SYMBOL(synchronize_irq);
63
64 #ifdef CONFIG_SMP
65 cpumask_var_t irq_default_affinity;
66
67 /**
68  *      irq_can_set_affinity - Check if the affinity of a given irq can be set
69  *      @irq:           Interrupt to check
70  *
71  */
72 int irq_can_set_affinity(unsigned int irq)
73 {
74         struct irq_desc *desc = irq_to_desc(irq);
75
76         if (CHECK_IRQ_PER_CPU(desc->status) || !desc->chip ||
77             !desc->chip->set_affinity)
78                 return 0;
79
80         return 1;
81 }
82
83 static void
84 irq_set_thread_affinity(struct irq_desc *desc, const struct cpumask *cpumask)
85 {
86         struct irqaction *action = desc->action;
87
88         while (action) {
89                 if (action->thread)
90                         set_cpus_allowed_ptr(action->thread, cpumask);
91                 action = action->next;
92         }
93 }
94
95 /**
96  *      irq_set_affinity - Set the irq affinity of a given irq
97  *      @irq:           Interrupt to set affinity
98  *      @cpumask:       cpumask
99  *
100  */
101 int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
102 {
103         struct irq_desc *desc = irq_to_desc(irq);
104         unsigned long flags;
105
106         if (!desc->chip->set_affinity)
107                 return -EINVAL;
108
109         spin_lock_irqsave(&desc->lock, flags);
110
111 #ifdef CONFIG_GENERIC_PENDING_IRQ
112         if (desc->status & IRQ_MOVE_PCNTXT || desc->status & IRQ_DISABLED) {
113                 cpumask_copy(desc->affinity, cpumask);
114                 desc->chip->set_affinity(irq, cpumask);
115         } else {
116                 desc->status |= IRQ_MOVE_PENDING;
117                 cpumask_copy(desc->pending_mask, cpumask);
118         }
119 #else
120         cpumask_copy(desc->affinity, cpumask);
121         desc->chip->set_affinity(irq, cpumask);
122 #endif
123         irq_set_thread_affinity(desc, cpumask);
124         desc->status |= IRQ_AFFINITY_SET;
125         spin_unlock_irqrestore(&desc->lock, flags);
126         return 0;
127 }
128
129 #ifndef CONFIG_AUTO_IRQ_AFFINITY
130 /*
131  * Generic version of the affinity autoselector.
132  */
133 static int setup_affinity(unsigned int irq, struct irq_desc *desc)
134 {
135         if (!irq_can_set_affinity(irq))
136                 return 0;
137
138         /*
139          * Preserve an userspace affinity setup, but make sure that
140          * one of the targets is online.
141          */
142         if (desc->status & (IRQ_AFFINITY_SET | IRQ_NO_BALANCING)) {
143                 if (cpumask_any_and(desc->affinity, cpu_online_mask)
144                     < nr_cpu_ids)
145                         goto set_affinity;
146                 else
147                         desc->status &= ~IRQ_AFFINITY_SET;
148         }
149
150         cpumask_and(desc->affinity, cpu_online_mask, irq_default_affinity);
151 set_affinity:
152         desc->chip->set_affinity(irq, desc->affinity);
153
154         return 0;
155 }
156 #else
157 static inline int setup_affinity(unsigned int irq, struct irq_desc *d)
158 {
159         return irq_select_affinity(irq);
160 }
161 #endif
162
163 /*
164  * Called when affinity is set via /proc/irq
165  */
166 int irq_select_affinity_usr(unsigned int irq)
167 {
168         struct irq_desc *desc = irq_to_desc(irq);
169         unsigned long flags;
170         int ret;
171
172         spin_lock_irqsave(&desc->lock, flags);
173         ret = setup_affinity(irq, desc);
174         if (!ret)
175                 irq_set_thread_affinity(desc, desc->affinity);
176         spin_unlock_irqrestore(&desc->lock, flags);
177
178         return ret;
179 }
180
181 #else
182 static inline int setup_affinity(unsigned int irq, struct irq_desc *desc)
183 {
184         return 0;
185 }
186 #endif
187
188 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
189 {
190         if (suspend) {
191                 if (!desc->action || (desc->action->flags & IRQF_TIMER))
192                         return;
193                 desc->status |= IRQ_SUSPENDED;
194         }
195
196         if (!desc->depth++) {
197                 desc->status |= IRQ_DISABLED;
198                 desc->chip->disable(irq);
199         }
200 }
201
202 /**
203  *      disable_irq_nosync - disable an irq without waiting
204  *      @irq: Interrupt to disable
205  *
206  *      Disable the selected interrupt line.  Disables and Enables are
207  *      nested.
208  *      Unlike disable_irq(), this function does not ensure existing
209  *      instances of the IRQ handler have completed before returning.
210  *
211  *      This function may be called from IRQ context.
212  */
213 void disable_irq_nosync(unsigned int irq)
214 {
215         struct irq_desc *desc = irq_to_desc(irq);
216         unsigned long flags;
217
218         if (!desc)
219                 return;
220
221         spin_lock_irqsave(&desc->lock, flags);
222         __disable_irq(desc, irq, false);
223         spin_unlock_irqrestore(&desc->lock, flags);
224 }
225 EXPORT_SYMBOL(disable_irq_nosync);
226
227 /**
228  *      disable_irq - disable an irq and wait for completion
229  *      @irq: Interrupt to disable
230  *
231  *      Disable the selected interrupt line.  Enables and Disables are
232  *      nested.
233  *      This function waits for any pending IRQ handlers for this interrupt
234  *      to complete before returning. If you use this function while
235  *      holding a resource the IRQ handler may need you will deadlock.
236  *
237  *      This function may be called - with care - from IRQ context.
238  */
239 void disable_irq(unsigned int irq)
240 {
241         struct irq_desc *desc = irq_to_desc(irq);
242
243         if (!desc)
244                 return;
245
246         disable_irq_nosync(irq);
247         if (desc->action)
248                 synchronize_irq(irq);
249 }
250 EXPORT_SYMBOL(disable_irq);
251
252 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
253 {
254         if (resume)
255                 desc->status &= ~IRQ_SUSPENDED;
256
257         switch (desc->depth) {
258         case 0:
259  err_out:
260                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
261                 break;
262         case 1: {
263                 unsigned int status = desc->status & ~IRQ_DISABLED;
264
265                 if (desc->status & IRQ_SUSPENDED)
266                         goto err_out;
267                 /* Prevent probing on this irq: */
268                 desc->status = status | IRQ_NOPROBE;
269                 check_irq_resend(desc, irq);
270                 /* fall-through */
271         }
272         default:
273                 desc->depth--;
274         }
275 }
276
277 /**
278  *      enable_irq - enable handling of an irq
279  *      @irq: Interrupt to enable
280  *
281  *      Undoes the effect of one call to disable_irq().  If this
282  *      matches the last disable, processing of interrupts on this
283  *      IRQ line is re-enabled.
284  *
285  *      This function may be called from IRQ context.
286  */
287 void enable_irq(unsigned int irq)
288 {
289         struct irq_desc *desc = irq_to_desc(irq);
290         unsigned long flags;
291
292         if (!desc)
293                 return;
294
295         spin_lock_irqsave(&desc->lock, flags);
296         __enable_irq(desc, irq, false);
297         spin_unlock_irqrestore(&desc->lock, flags);
298 }
299 EXPORT_SYMBOL(enable_irq);
300
301 static int set_irq_wake_real(unsigned int irq, unsigned int on)
302 {
303         struct irq_desc *desc = irq_to_desc(irq);
304         int ret = -ENXIO;
305
306         if (desc->chip->set_wake)
307                 ret = desc->chip->set_wake(irq, on);
308
309         return ret;
310 }
311
312 /**
313  *      set_irq_wake - control irq power management wakeup
314  *      @irq:   interrupt to control
315  *      @on:    enable/disable power management wakeup
316  *
317  *      Enable/disable power management wakeup mode, which is
318  *      disabled by default.  Enables and disables must match,
319  *      just as they match for non-wakeup mode support.
320  *
321  *      Wakeup mode lets this IRQ wake the system from sleep
322  *      states like "suspend to RAM".
323  */
324 int set_irq_wake(unsigned int irq, unsigned int on)
325 {
326         struct irq_desc *desc = irq_to_desc(irq);
327         unsigned long flags;
328         int ret = 0;
329
330         /* wakeup-capable irqs can be shared between drivers that
331          * don't need to have the same sleep mode behaviors.
332          */
333         spin_lock_irqsave(&desc->lock, flags);
334         if (on) {
335                 if (desc->wake_depth++ == 0) {
336                         ret = set_irq_wake_real(irq, on);
337                         if (ret)
338                                 desc->wake_depth = 0;
339                         else
340                                 desc->status |= IRQ_WAKEUP;
341                 }
342         } else {
343                 if (desc->wake_depth == 0) {
344                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
345                 } else if (--desc->wake_depth == 0) {
346                         ret = set_irq_wake_real(irq, on);
347                         if (ret)
348                                 desc->wake_depth = 1;
349                         else
350                                 desc->status &= ~IRQ_WAKEUP;
351                 }
352         }
353
354         spin_unlock_irqrestore(&desc->lock, flags);
355         return ret;
356 }
357 EXPORT_SYMBOL(set_irq_wake);
358
359 /*
360  * Internal function that tells the architecture code whether a
361  * particular irq has been exclusively allocated or is available
362  * for driver use.
363  */
364 int can_request_irq(unsigned int irq, unsigned long irqflags)
365 {
366         struct irq_desc *desc = irq_to_desc(irq);
367         struct irqaction *action;
368
369         if (!desc)
370                 return 0;
371
372         if (desc->status & IRQ_NOREQUEST)
373                 return 0;
374
375         action = desc->action;
376         if (action)
377                 if (irqflags & action->flags & IRQF_SHARED)
378                         action = NULL;
379
380         return !action;
381 }
382
383 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
384 {
385         /*
386          * If the architecture still has not overriden
387          * the flow handler then zap the default. This
388          * should catch incorrect flow-type setting.
389          */
390         if (desc->handle_irq == &handle_bad_irq)
391                 desc->handle_irq = NULL;
392 }
393
394 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
395                 unsigned long flags)
396 {
397         int ret;
398         struct irq_chip *chip = desc->chip;
399
400         if (!chip || !chip->set_type) {
401                 /*
402                  * IRQF_TRIGGER_* but the PIC does not support multiple
403                  * flow-types?
404                  */
405                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
406                                 chip ? (chip->name ? : "unknown") : "unknown");
407                 return 0;
408         }
409
410         /* caller masked out all except trigger mode flags */
411         ret = chip->set_type(irq, flags);
412
413         if (ret)
414                 pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
415                                 (int)flags, irq, chip->set_type);
416         else {
417                 if (flags & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
418                         flags |= IRQ_LEVEL;
419                 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
420                 desc->status &= ~(IRQ_LEVEL | IRQ_TYPE_SENSE_MASK);
421                 desc->status |= flags;
422         }
423
424         return ret;
425 }
426
427 static int irq_wait_for_interrupt(struct irqaction *action)
428 {
429         while (!kthread_should_stop()) {
430                 set_current_state(TASK_INTERRUPTIBLE);
431
432                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
433                                        &action->thread_flags)) {
434                         __set_current_state(TASK_RUNNING);
435                         return 0;
436                 }
437                 schedule();
438         }
439         return -1;
440 }
441
442 /*
443  * Interrupt handler thread
444  */
445 static int irq_thread(void *data)
446 {
447         struct sched_param param = { .sched_priority = MAX_USER_RT_PRIO/2, };
448         struct irqaction *action = data;
449         struct irq_desc *desc = irq_to_desc(action->irq);
450         int wake;
451
452         sched_setscheduler(current, SCHED_FIFO, &param);
453         current->irqaction = action;
454
455         while (!irq_wait_for_interrupt(action)) {
456
457                 atomic_inc(&desc->threads_active);
458
459                 spin_lock_irq(&desc->lock);
460                 if (unlikely(desc->status & IRQ_DISABLED)) {
461                         /*
462                          * CHECKME: We might need a dedicated
463                          * IRQ_THREAD_PENDING flag here, which
464                          * retriggers the thread in check_irq_resend()
465                          * but AFAICT IRQ_PENDING should be fine as it
466                          * retriggers the interrupt itself --- tglx
467                          */
468                         desc->status |= IRQ_PENDING;
469                         spin_unlock_irq(&desc->lock);
470                 } else {
471                         spin_unlock_irq(&desc->lock);
472
473                         action->thread_fn(action->irq, action->dev_id);
474                 }
475
476                 wake = atomic_dec_and_test(&desc->threads_active);
477
478                 if (wake && waitqueue_active(&desc->wait_for_threads))
479                         wake_up(&desc->wait_for_threads);
480         }
481
482         /*
483          * Clear irqaction. Otherwise exit_irq_thread() would make
484          * fuzz about an active irq thread going into nirvana.
485          */
486         current->irqaction = NULL;
487         return 0;
488 }
489
490 /*
491  * Called from do_exit()
492  */
493 void exit_irq_thread(void)
494 {
495         struct task_struct *tsk = current;
496
497         if (!tsk->irqaction)
498                 return;
499
500         printk(KERN_ERR
501                "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
502                tsk->comm ? tsk->comm : "", tsk->pid, tsk->irqaction->irq);
503
504         /*
505          * Set the THREAD DIED flag to prevent further wakeups of the
506          * soon to be gone threaded handler.
507          */
508         set_bit(IRQTF_DIED, &tsk->irqaction->flags);
509 }
510
511 /*
512  * Internal function to register an irqaction - typically used to
513  * allocate special interrupts that are part of the architecture.
514  */
515 static int
516 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
517 {
518         struct irqaction *old, **old_ptr;
519         const char *old_name = NULL;
520         unsigned long flags;
521         int shared = 0;
522         int ret;
523
524         if (!desc)
525                 return -EINVAL;
526
527         if (desc->chip == &no_irq_chip)
528                 return -ENOSYS;
529         /*
530          * Some drivers like serial.c use request_irq() heavily,
531          * so we have to be careful not to interfere with a
532          * running system.
533          */
534         if (new->flags & IRQF_SAMPLE_RANDOM) {
535                 /*
536                  * This function might sleep, we want to call it first,
537                  * outside of the atomic block.
538                  * Yes, this might clear the entropy pool if the wrong
539                  * driver is attempted to be loaded, without actually
540                  * installing a new handler, but is this really a problem,
541                  * only the sysadmin is able to do this.
542                  */
543                 rand_initialize_irq(irq);
544         }
545
546         /*
547          * Threaded handler ?
548          */
549         if (new->thread_fn) {
550                 struct task_struct *t;
551
552                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
553                                    new->name);
554                 if (IS_ERR(t))
555                         return PTR_ERR(t);
556                 /*
557                  * We keep the reference to the task struct even if
558                  * the thread dies to avoid that the interrupt code
559                  * references an already freed task_struct.
560                  */
561                 get_task_struct(t);
562                 new->thread = t;
563                 wake_up_process(t);
564         }
565
566         /*
567          * The following block of code has to be executed atomically
568          */
569         spin_lock_irqsave(&desc->lock, flags);
570         old_ptr = &desc->action;
571         old = *old_ptr;
572         if (old) {
573                 /*
574                  * Can't share interrupts unless both agree to and are
575                  * the same type (level, edge, polarity). So both flag
576                  * fields must have IRQF_SHARED set and the bits which
577                  * set the trigger type must match.
578                  */
579                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
580                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
581                         old_name = old->name;
582                         goto mismatch;
583                 }
584
585 #if defined(CONFIG_IRQ_PER_CPU)
586                 /* All handlers must agree on per-cpuness */
587                 if ((old->flags & IRQF_PERCPU) !=
588                     (new->flags & IRQF_PERCPU))
589                         goto mismatch;
590 #endif
591
592                 /* add new interrupt at end of irq queue */
593                 do {
594                         old_ptr = &old->next;
595                         old = *old_ptr;
596                 } while (old);
597                 shared = 1;
598         }
599
600         if (!shared) {
601                 irq_chip_set_defaults(desc->chip);
602
603                 init_waitqueue_head(&desc->wait_for_threads);
604
605                 /* Setup the type (level, edge polarity) if configured: */
606                 if (new->flags & IRQF_TRIGGER_MASK) {
607                         ret = __irq_set_trigger(desc, irq,
608                                         new->flags & IRQF_TRIGGER_MASK);
609
610                         if (ret)
611                                 goto out_thread;
612                 } else
613                         compat_irq_chip_set_default_handler(desc);
614 #if defined(CONFIG_IRQ_PER_CPU)
615                 if (new->flags & IRQF_PERCPU)
616                         desc->status |= IRQ_PER_CPU;
617 #endif
618
619                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
620                                   IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
621
622                 if (!(desc->status & IRQ_NOAUTOEN)) {
623                         desc->depth = 0;
624                         desc->status &= ~IRQ_DISABLED;
625                         desc->chip->startup(irq);
626                 } else
627                         /* Undo nested disables: */
628                         desc->depth = 1;
629
630                 /* Exclude IRQ from balancing if requested */
631                 if (new->flags & IRQF_NOBALANCING)
632                         desc->status |= IRQ_NO_BALANCING;
633
634                 /* Set default affinity mask once everything is setup */
635                 setup_affinity(irq, desc);
636
637         } else if ((new->flags & IRQF_TRIGGER_MASK)
638                         && (new->flags & IRQF_TRIGGER_MASK)
639                                 != (desc->status & IRQ_TYPE_SENSE_MASK)) {
640                 /* hope the handler works with the actual trigger mode... */
641                 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
642                                 irq, (int)(desc->status & IRQ_TYPE_SENSE_MASK),
643                                 (int)(new->flags & IRQF_TRIGGER_MASK));
644         }
645
646         *old_ptr = new;
647
648         /* Reset broken irq detection when installing new handler */
649         desc->irq_count = 0;
650         desc->irqs_unhandled = 0;
651
652         /*
653          * Check whether we disabled the irq via the spurious handler
654          * before. Reenable it and give it another chance.
655          */
656         if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
657                 desc->status &= ~IRQ_SPURIOUS_DISABLED;
658                 __enable_irq(desc, irq, false);
659         }
660
661         spin_unlock_irqrestore(&desc->lock, flags);
662
663         new->irq = irq;
664         register_irq_proc(irq, desc);
665         new->dir = NULL;
666         register_handler_proc(irq, new);
667
668         return 0;
669
670 mismatch:
671 #ifdef CONFIG_DEBUG_SHIRQ
672         if (!(new->flags & IRQF_PROBE_SHARED)) {
673                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
674                 if (old_name)
675                         printk(KERN_ERR "current handler: %s\n", old_name);
676                 dump_stack();
677         }
678 #endif
679         ret = -EBUSY;
680
681 out_thread:
682         spin_unlock_irqrestore(&desc->lock, flags);
683         if (new->thread) {
684                 struct task_struct *t = new->thread;
685
686                 new->thread = NULL;
687                 if (likely(!test_bit(IRQTF_DIED, &new->thread_flags)))
688                         kthread_stop(t);
689                 put_task_struct(t);
690         }
691         return ret;
692 }
693
694 /**
695  *      setup_irq - setup an interrupt
696  *      @irq: Interrupt line to setup
697  *      @act: irqaction for the interrupt
698  *
699  * Used to statically setup interrupts in the early boot process.
700  */
701 int setup_irq(unsigned int irq, struct irqaction *act)
702 {
703         struct irq_desc *desc = irq_to_desc(irq);
704
705         return __setup_irq(irq, desc, act);
706 }
707 EXPORT_SYMBOL_GPL(setup_irq);
708
709  /*
710  * Internal function to unregister an irqaction - used to free
711  * regular and special interrupts that are part of the architecture.
712  */
713 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
714 {
715         struct irq_desc *desc = irq_to_desc(irq);
716         struct irqaction *action, **action_ptr;
717         struct task_struct *irqthread;
718         unsigned long flags;
719
720         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
721
722         if (!desc)
723                 return NULL;
724
725         spin_lock_irqsave(&desc->lock, flags);
726
727         /*
728          * There can be multiple actions per IRQ descriptor, find the right
729          * one based on the dev_id:
730          */
731         action_ptr = &desc->action;
732         for (;;) {
733                 action = *action_ptr;
734
735                 if (!action) {
736                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
737                         spin_unlock_irqrestore(&desc->lock, flags);
738
739                         return NULL;
740                 }
741
742                 if (action->dev_id == dev_id)
743                         break;
744                 action_ptr = &action->next;
745         }
746
747         /* Found it - now remove it from the list of entries: */
748         *action_ptr = action->next;
749
750         /* Currently used only by UML, might disappear one day: */
751 #ifdef CONFIG_IRQ_RELEASE_METHOD
752         if (desc->chip->release)
753                 desc->chip->release(irq, dev_id);
754 #endif
755
756         /* If this was the last handler, shut down the IRQ line: */
757         if (!desc->action) {
758                 desc->status |= IRQ_DISABLED;
759                 if (desc->chip->shutdown)
760                         desc->chip->shutdown(irq);
761                 else
762                         desc->chip->disable(irq);
763         }
764
765         irqthread = action->thread;
766         action->thread = NULL;
767
768         spin_unlock_irqrestore(&desc->lock, flags);
769
770         unregister_handler_proc(irq, action);
771
772         /* Make sure it's not being used on another CPU: */
773         synchronize_irq(irq);
774
775         if (irqthread) {
776                 if (!test_bit(IRQTF_DIED, &action->thread_flags))
777                         kthread_stop(irqthread);
778                 put_task_struct(irqthread);
779         }
780
781 #ifdef CONFIG_DEBUG_SHIRQ
782         /*
783          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
784          * event to happen even now it's being freed, so let's make sure that
785          * is so by doing an extra call to the handler ....
786          *
787          * ( We do this after actually deregistering it, to make sure that a
788          *   'real' IRQ doesn't run in * parallel with our fake. )
789          */
790         if (action->flags & IRQF_SHARED) {
791                 local_irq_save(flags);
792                 action->handler(irq, dev_id);
793                 local_irq_restore(flags);
794         }
795 #endif
796         return action;
797 }
798
799 /**
800  *      remove_irq - free an interrupt
801  *      @irq: Interrupt line to free
802  *      @act: irqaction for the interrupt
803  *
804  * Used to remove interrupts statically setup by the early boot process.
805  */
806 void remove_irq(unsigned int irq, struct irqaction *act)
807 {
808         __free_irq(irq, act->dev_id);
809 }
810 EXPORT_SYMBOL_GPL(remove_irq);
811
812 /**
813  *      free_irq - free an interrupt allocated with request_irq
814  *      @irq: Interrupt line to free
815  *      @dev_id: Device identity to free
816  *
817  *      Remove an interrupt handler. The handler is removed and if the
818  *      interrupt line is no longer in use by any driver it is disabled.
819  *      On a shared IRQ the caller must ensure the interrupt is disabled
820  *      on the card it drives before calling this function. The function
821  *      does not return until any executing interrupts for this IRQ
822  *      have completed.
823  *
824  *      This function must not be called from interrupt context.
825  */
826 void free_irq(unsigned int irq, void *dev_id)
827 {
828         kfree(__free_irq(irq, dev_id));
829 }
830 EXPORT_SYMBOL(free_irq);
831
832 /**
833  *      request_threaded_irq - allocate an interrupt line
834  *      @irq: Interrupt line to allocate
835  *      @handler: Function to be called when the IRQ occurs.
836  *                Primary handler for threaded interrupts
837  *      @thread_fn: Function called from the irq handler thread
838  *                  If NULL, no irq thread is created
839  *      @irqflags: Interrupt type flags
840  *      @devname: An ascii name for the claiming device
841  *      @dev_id: A cookie passed back to the handler function
842  *
843  *      This call allocates interrupt resources and enables the
844  *      interrupt line and IRQ handling. From the point this
845  *      call is made your handler function may be invoked. Since
846  *      your handler function must clear any interrupt the board
847  *      raises, you must take care both to initialise your hardware
848  *      and to set up the interrupt handler in the right order.
849  *
850  *      If you want to set up a threaded irq handler for your device
851  *      then you need to supply @handler and @thread_fn. @handler ist
852  *      still called in hard interrupt context and has to check
853  *      whether the interrupt originates from the device. If yes it
854  *      needs to disable the interrupt on the device and return
855  *      IRQ_THREAD_WAKE which will wake up the handler thread and run
856  *      @thread_fn. This split handler design is necessary to support
857  *      shared interrupts.
858  *
859  *      Dev_id must be globally unique. Normally the address of the
860  *      device data structure is used as the cookie. Since the handler
861  *      receives this value it makes sense to use it.
862  *
863  *      If your interrupt is shared you must pass a non NULL dev_id
864  *      as this is required when freeing the interrupt.
865  *
866  *      Flags:
867  *
868  *      IRQF_SHARED             Interrupt is shared
869  *      IRQF_DISABLED   Disable local interrupts while processing
870  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
871  *      IRQF_TRIGGER_*          Specify active edge(s) or level
872  *
873  */
874 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
875                          irq_handler_t thread_fn, unsigned long irqflags,
876                          const char *devname, void *dev_id)
877 {
878         struct irqaction *action;
879         struct irq_desc *desc;
880         int retval;
881
882         /*
883          * handle_IRQ_event() always ignores IRQF_DISABLED except for
884          * the _first_ irqaction (sigh).  That can cause oopsing, but
885          * the behavior is classified as "will not fix" so we need to
886          * start nudging drivers away from using that idiom.
887          */
888         if ((irqflags & (IRQF_SHARED|IRQF_DISABLED)) ==
889                                         (IRQF_SHARED|IRQF_DISABLED)) {
890                 pr_warning(
891                   "IRQ %d/%s: IRQF_DISABLED is not guaranteed on shared IRQs\n",
892                         irq, devname);
893         }
894
895 #ifdef CONFIG_LOCKDEP
896         /*
897          * Lockdep wants atomic interrupt handlers:
898          */
899         irqflags |= IRQF_DISABLED;
900 #endif
901         /*
902          * Sanity-check: shared interrupts must pass in a real dev-ID,
903          * otherwise we'll have trouble later trying to figure out
904          * which interrupt is which (messes up the interrupt freeing
905          * logic etc).
906          */
907         if ((irqflags & IRQF_SHARED) && !dev_id)
908                 return -EINVAL;
909
910         desc = irq_to_desc(irq);
911         if (!desc)
912                 return -EINVAL;
913
914         if (desc->status & IRQ_NOREQUEST)
915                 return -EINVAL;
916         if (!handler)
917                 return -EINVAL;
918
919         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
920         if (!action)
921                 return -ENOMEM;
922
923         action->handler = handler;
924         action->thread_fn = thread_fn;
925         action->flags = irqflags;
926         action->name = devname;
927         action->dev_id = dev_id;
928
929         retval = __setup_irq(irq, desc, action);
930         if (retval)
931                 kfree(action);
932
933 #ifdef CONFIG_DEBUG_SHIRQ
934         if (irqflags & IRQF_SHARED) {
935                 /*
936                  * It's a shared IRQ -- the driver ought to be prepared for it
937                  * to happen immediately, so let's make sure....
938                  * We disable the irq to make sure that a 'real' IRQ doesn't
939                  * run in parallel with our fake.
940                  */
941                 unsigned long flags;
942
943                 disable_irq(irq);
944                 local_irq_save(flags);
945
946                 handler(irq, dev_id);
947
948                 local_irq_restore(flags);
949                 enable_irq(irq);
950         }
951 #endif
952         return retval;
953 }
954 EXPORT_SYMBOL(request_threaded_irq);