50da676729013dfe8dbc7929a4fdec16412f7780
[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 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) {
113                 if (!desc->chip->set_affinity(irq, cpumask)) {
114                         cpumask_copy(desc->affinity, cpumask);
115                         irq_set_thread_affinity(desc, cpumask);
116                 }
117         }
118         else {
119                 desc->status |= IRQ_MOVE_PENDING;
120                 cpumask_copy(desc->pending_mask, cpumask);
121         }
122 #else
123         if (!desc->chip->set_affinity(irq, cpumask)) {
124                 cpumask_copy(desc->affinity, cpumask);
125                 irq_set_thread_affinity(desc, cpumask);
126         }
127 #endif
128         desc->status |= IRQ_AFFINITY_SET;
129         spin_unlock_irqrestore(&desc->lock, flags);
130         return 0;
131 }
132
133 #ifndef CONFIG_AUTO_IRQ_AFFINITY
134 /*
135  * Generic version of the affinity autoselector.
136  */
137 static int setup_affinity(unsigned int irq, struct irq_desc *desc)
138 {
139         if (!irq_can_set_affinity(irq))
140                 return 0;
141
142         /*
143          * Preserve an userspace affinity setup, but make sure that
144          * one of the targets is online.
145          */
146         if (desc->status & (IRQ_AFFINITY_SET | IRQ_NO_BALANCING)) {
147                 if (cpumask_any_and(desc->affinity, cpu_online_mask)
148                     < nr_cpu_ids)
149                         goto set_affinity;
150                 else
151                         desc->status &= ~IRQ_AFFINITY_SET;
152         }
153
154         cpumask_and(desc->affinity, cpu_online_mask, irq_default_affinity);
155 set_affinity:
156         desc->chip->set_affinity(irq, desc->affinity);
157
158         return 0;
159 }
160 #else
161 static inline int setup_affinity(unsigned int irq, struct irq_desc *d)
162 {
163         return irq_select_affinity(irq);
164 }
165 #endif
166
167 /*
168  * Called when affinity is set via /proc/irq
169  */
170 int irq_select_affinity_usr(unsigned int irq)
171 {
172         struct irq_desc *desc = irq_to_desc(irq);
173         unsigned long flags;
174         int ret;
175
176         spin_lock_irqsave(&desc->lock, flags);
177         ret = setup_affinity(irq, desc);
178         if (!ret)
179                 irq_set_thread_affinity(desc, desc->affinity);
180         spin_unlock_irqrestore(&desc->lock, flags);
181
182         return ret;
183 }
184
185 #else
186 static inline int setup_affinity(unsigned int irq, struct irq_desc *desc)
187 {
188         return 0;
189 }
190 #endif
191
192 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
193 {
194         if (suspend) {
195                 if (!desc->action || (desc->action->flags & IRQF_TIMER))
196                         return;
197                 desc->status |= IRQ_SUSPENDED;
198         }
199
200         if (!desc->depth++) {
201                 desc->status |= IRQ_DISABLED;
202                 desc->chip->disable(irq);
203         }
204 }
205
206 /**
207  *      disable_irq_nosync - disable an irq without waiting
208  *      @irq: Interrupt to disable
209  *
210  *      Disable the selected interrupt line.  Disables and Enables are
211  *      nested.
212  *      Unlike disable_irq(), this function does not ensure existing
213  *      instances of the IRQ handler have completed before returning.
214  *
215  *      This function may be called from IRQ context.
216  */
217 void disable_irq_nosync(unsigned int irq)
218 {
219         struct irq_desc *desc = irq_to_desc(irq);
220         unsigned long flags;
221
222         if (!desc)
223                 return;
224
225         spin_lock_irqsave(&desc->lock, flags);
226         __disable_irq(desc, irq, false);
227         spin_unlock_irqrestore(&desc->lock, flags);
228 }
229 EXPORT_SYMBOL(disable_irq_nosync);
230
231 /**
232  *      disable_irq - disable an irq and wait for completion
233  *      @irq: Interrupt to disable
234  *
235  *      Disable the selected interrupt line.  Enables and Disables are
236  *      nested.
237  *      This function waits for any pending IRQ handlers for this interrupt
238  *      to complete before returning. If you use this function while
239  *      holding a resource the IRQ handler may need you will deadlock.
240  *
241  *      This function may be called - with care - from IRQ context.
242  */
243 void disable_irq(unsigned int irq)
244 {
245         struct irq_desc *desc = irq_to_desc(irq);
246
247         if (!desc)
248                 return;
249
250         disable_irq_nosync(irq);
251         if (desc->action)
252                 synchronize_irq(irq);
253 }
254 EXPORT_SYMBOL(disable_irq);
255
256 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
257 {
258         if (resume)
259                 desc->status &= ~IRQ_SUSPENDED;
260
261         switch (desc->depth) {
262         case 0:
263  err_out:
264                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
265                 break;
266         case 1: {
267                 unsigned int status = desc->status & ~IRQ_DISABLED;
268
269                 if (desc->status & IRQ_SUSPENDED)
270                         goto err_out;
271                 /* Prevent probing on this irq: */
272                 desc->status = status | IRQ_NOPROBE;
273                 check_irq_resend(desc, irq);
274                 /* fall-through */
275         }
276         default:
277                 desc->depth--;
278         }
279 }
280
281 /**
282  *      enable_irq - enable handling of an irq
283  *      @irq: Interrupt to enable
284  *
285  *      Undoes the effect of one call to disable_irq().  If this
286  *      matches the last disable, processing of interrupts on this
287  *      IRQ line is re-enabled.
288  *
289  *      This function may be called from IRQ context.
290  */
291 void enable_irq(unsigned int irq)
292 {
293         struct irq_desc *desc = irq_to_desc(irq);
294         unsigned long flags;
295
296         if (!desc)
297                 return;
298
299         spin_lock_irqsave(&desc->lock, flags);
300         __enable_irq(desc, irq, false);
301         spin_unlock_irqrestore(&desc->lock, flags);
302 }
303 EXPORT_SYMBOL(enable_irq);
304
305 static int set_irq_wake_real(unsigned int irq, unsigned int on)
306 {
307         struct irq_desc *desc = irq_to_desc(irq);
308         int ret = -ENXIO;
309
310         if (desc->chip->set_wake)
311                 ret = desc->chip->set_wake(irq, on);
312
313         return ret;
314 }
315
316 /**
317  *      set_irq_wake - control irq power management wakeup
318  *      @irq:   interrupt to control
319  *      @on:    enable/disable power management wakeup
320  *
321  *      Enable/disable power management wakeup mode, which is
322  *      disabled by default.  Enables and disables must match,
323  *      just as they match for non-wakeup mode support.
324  *
325  *      Wakeup mode lets this IRQ wake the system from sleep
326  *      states like "suspend to RAM".
327  */
328 int set_irq_wake(unsigned int irq, unsigned int on)
329 {
330         struct irq_desc *desc = irq_to_desc(irq);
331         unsigned long flags;
332         int ret = 0;
333
334         /* wakeup-capable irqs can be shared between drivers that
335          * don't need to have the same sleep mode behaviors.
336          */
337         spin_lock_irqsave(&desc->lock, flags);
338         if (on) {
339                 if (desc->wake_depth++ == 0) {
340                         ret = set_irq_wake_real(irq, on);
341                         if (ret)
342                                 desc->wake_depth = 0;
343                         else
344                                 desc->status |= IRQ_WAKEUP;
345                 }
346         } else {
347                 if (desc->wake_depth == 0) {
348                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
349                 } else if (--desc->wake_depth == 0) {
350                         ret = set_irq_wake_real(irq, on);
351                         if (ret)
352                                 desc->wake_depth = 1;
353                         else
354                                 desc->status &= ~IRQ_WAKEUP;
355                 }
356         }
357
358         spin_unlock_irqrestore(&desc->lock, flags);
359         return ret;
360 }
361 EXPORT_SYMBOL(set_irq_wake);
362
363 /*
364  * Internal function that tells the architecture code whether a
365  * particular irq has been exclusively allocated or is available
366  * for driver use.
367  */
368 int can_request_irq(unsigned int irq, unsigned long irqflags)
369 {
370         struct irq_desc *desc = irq_to_desc(irq);
371         struct irqaction *action;
372
373         if (!desc)
374                 return 0;
375
376         if (desc->status & IRQ_NOREQUEST)
377                 return 0;
378
379         action = desc->action;
380         if (action)
381                 if (irqflags & action->flags & IRQF_SHARED)
382                         action = NULL;
383
384         return !action;
385 }
386
387 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
388 {
389         /*
390          * If the architecture still has not overriden
391          * the flow handler then zap the default. This
392          * should catch incorrect flow-type setting.
393          */
394         if (desc->handle_irq == &handle_bad_irq)
395                 desc->handle_irq = NULL;
396 }
397
398 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
399                 unsigned long flags)
400 {
401         int ret;
402         struct irq_chip *chip = desc->chip;
403
404         if (!chip || !chip->set_type) {
405                 /*
406                  * IRQF_TRIGGER_* but the PIC does not support multiple
407                  * flow-types?
408                  */
409                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
410                                 chip ? (chip->name ? : "unknown") : "unknown");
411                 return 0;
412         }
413
414         /* caller masked out all except trigger mode flags */
415         ret = chip->set_type(irq, flags);
416
417         if (ret)
418                 pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
419                                 (int)flags, irq, chip->set_type);
420         else {
421                 if (flags & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
422                         flags |= IRQ_LEVEL;
423                 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
424                 desc->status &= ~(IRQ_LEVEL | IRQ_TYPE_SENSE_MASK);
425                 desc->status |= flags;
426         }
427
428         return ret;
429 }
430
431 static int irq_wait_for_interrupt(struct irqaction *action)
432 {
433         while (!kthread_should_stop()) {
434                 set_current_state(TASK_INTERRUPTIBLE);
435
436                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
437                                        &action->thread_flags)) {
438                         __set_current_state(TASK_RUNNING);
439                         return 0;
440                 }
441                 schedule();
442         }
443         return -1;
444 }
445
446 /*
447  * Interrupt handler thread
448  */
449 static int irq_thread(void *data)
450 {
451         struct sched_param param = { .sched_priority = MAX_USER_RT_PRIO/2, };
452         struct irqaction *action = data;
453         struct irq_desc *desc = irq_to_desc(action->irq);
454         int wake;
455
456         sched_setscheduler(current, SCHED_FIFO, &param);
457         current->irqaction = action;
458
459         while (!irq_wait_for_interrupt(action)) {
460
461                 atomic_inc(&desc->threads_active);
462
463                 spin_lock_irq(&desc->lock);
464                 if (unlikely(desc->status & IRQ_DISABLED)) {
465                         /*
466                          * CHECKME: We might need a dedicated
467                          * IRQ_THREAD_PENDING flag here, which
468                          * retriggers the thread in check_irq_resend()
469                          * but AFAICT IRQ_PENDING should be fine as it
470                          * retriggers the interrupt itself --- tglx
471                          */
472                         desc->status |= IRQ_PENDING;
473                         spin_unlock_irq(&desc->lock);
474                 } else {
475                         spin_unlock_irq(&desc->lock);
476
477                         action->thread_fn(action->irq, action->dev_id);
478                 }
479
480                 wake = atomic_dec_and_test(&desc->threads_active);
481
482                 if (wake && waitqueue_active(&desc->wait_for_threads))
483                         wake_up(&desc->wait_for_threads);
484         }
485
486         /*
487          * Clear irqaction. Otherwise exit_irq_thread() would make
488          * fuzz about an active irq thread going into nirvana.
489          */
490         current->irqaction = NULL;
491         return 0;
492 }
493
494 /*
495  * Called from do_exit()
496  */
497 void exit_irq_thread(void)
498 {
499         struct task_struct *tsk = current;
500
501         if (!tsk->irqaction)
502                 return;
503
504         printk(KERN_ERR
505                "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
506                tsk->comm ? tsk->comm : "", tsk->pid, tsk->irqaction->irq);
507
508         /*
509          * Set the THREAD DIED flag to prevent further wakeups of the
510          * soon to be gone threaded handler.
511          */
512         set_bit(IRQTF_DIED, &tsk->irqaction->flags);
513 }
514
515 /*
516  * Internal function to register an irqaction - typically used to
517  * allocate special interrupts that are part of the architecture.
518  */
519 static int
520 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
521 {
522         struct irqaction *old, **old_ptr;
523         const char *old_name = NULL;
524         unsigned long flags;
525         int shared = 0;
526         int ret;
527
528         if (!desc)
529                 return -EINVAL;
530
531         if (desc->chip == &no_irq_chip)
532                 return -ENOSYS;
533         /*
534          * Some drivers like serial.c use request_irq() heavily,
535          * so we have to be careful not to interfere with a
536          * running system.
537          */
538         if (new->flags & IRQF_SAMPLE_RANDOM) {
539                 /*
540                  * This function might sleep, we want to call it first,
541                  * outside of the atomic block.
542                  * Yes, this might clear the entropy pool if the wrong
543                  * driver is attempted to be loaded, without actually
544                  * installing a new handler, but is this really a problem,
545                  * only the sysadmin is able to do this.
546                  */
547                 rand_initialize_irq(irq);
548         }
549
550         /*
551          * Threaded handler ?
552          */
553         if (new->thread_fn) {
554                 struct task_struct *t;
555
556                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
557                                    new->name);
558                 if (IS_ERR(t))
559                         return PTR_ERR(t);
560                 /*
561                  * We keep the reference to the task struct even if
562                  * the thread dies to avoid that the interrupt code
563                  * references an already freed task_struct.
564                  */
565                 get_task_struct(t);
566                 new->thread = t;
567                 wake_up_process(t);
568         }
569
570         /*
571          * The following block of code has to be executed atomically
572          */
573         spin_lock_irqsave(&desc->lock, flags);
574         old_ptr = &desc->action;
575         old = *old_ptr;
576         if (old) {
577                 /*
578                  * Can't share interrupts unless both agree to and are
579                  * the same type (level, edge, polarity). So both flag
580                  * fields must have IRQF_SHARED set and the bits which
581                  * set the trigger type must match.
582                  */
583                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
584                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
585                         old_name = old->name;
586                         goto mismatch;
587                 }
588
589 #if defined(CONFIG_IRQ_PER_CPU)
590                 /* All handlers must agree on per-cpuness */
591                 if ((old->flags & IRQF_PERCPU) !=
592                     (new->flags & IRQF_PERCPU))
593                         goto mismatch;
594 #endif
595
596                 /* add new interrupt at end of irq queue */
597                 do {
598                         old_ptr = &old->next;
599                         old = *old_ptr;
600                 } while (old);
601                 shared = 1;
602         }
603
604         if (!shared) {
605                 irq_chip_set_defaults(desc->chip);
606
607                 init_waitqueue_head(&desc->wait_for_threads);
608
609                 /* Setup the type (level, edge polarity) if configured: */
610                 if (new->flags & IRQF_TRIGGER_MASK) {
611                         ret = __irq_set_trigger(desc, irq,
612                                         new->flags & IRQF_TRIGGER_MASK);
613
614                         if (ret)
615                                 goto out_thread;
616                 } else
617                         compat_irq_chip_set_default_handler(desc);
618 #if defined(CONFIG_IRQ_PER_CPU)
619                 if (new->flags & IRQF_PERCPU)
620                         desc->status |= IRQ_PER_CPU;
621 #endif
622
623                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
624                                   IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
625
626                 if (!(desc->status & IRQ_NOAUTOEN)) {
627                         desc->depth = 0;
628                         desc->status &= ~IRQ_DISABLED;
629                         desc->chip->startup(irq);
630                 } else
631                         /* Undo nested disables: */
632                         desc->depth = 1;
633
634                 /* Exclude IRQ from balancing if requested */
635                 if (new->flags & IRQF_NOBALANCING)
636                         desc->status |= IRQ_NO_BALANCING;
637
638                 /* Set default affinity mask once everything is setup */
639                 setup_affinity(irq, desc);
640
641         } else if ((new->flags & IRQF_TRIGGER_MASK)
642                         && (new->flags & IRQF_TRIGGER_MASK)
643                                 != (desc->status & IRQ_TYPE_SENSE_MASK)) {
644                 /* hope the handler works with the actual trigger mode... */
645                 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
646                                 irq, (int)(desc->status & IRQ_TYPE_SENSE_MASK),
647                                 (int)(new->flags & IRQF_TRIGGER_MASK));
648         }
649
650         *old_ptr = new;
651
652         /* Reset broken irq detection when installing new handler */
653         desc->irq_count = 0;
654         desc->irqs_unhandled = 0;
655
656         /*
657          * Check whether we disabled the irq via the spurious handler
658          * before. Reenable it and give it another chance.
659          */
660         if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
661                 desc->status &= ~IRQ_SPURIOUS_DISABLED;
662                 __enable_irq(desc, irq, false);
663         }
664
665         spin_unlock_irqrestore(&desc->lock, flags);
666
667         new->irq = irq;
668         register_irq_proc(irq, desc);
669         new->dir = NULL;
670         register_handler_proc(irq, new);
671
672         return 0;
673
674 mismatch:
675 #ifdef CONFIG_DEBUG_SHIRQ
676         if (!(new->flags & IRQF_PROBE_SHARED)) {
677                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
678                 if (old_name)
679                         printk(KERN_ERR "current handler: %s\n", old_name);
680                 dump_stack();
681         }
682 #endif
683         ret = -EBUSY;
684
685 out_thread:
686         spin_unlock_irqrestore(&desc->lock, flags);
687         if (new->thread) {
688                 struct task_struct *t = new->thread;
689
690                 new->thread = NULL;
691                 if (likely(!test_bit(IRQTF_DIED, &new->thread_flags)))
692                         kthread_stop(t);
693                 put_task_struct(t);
694         }
695         return ret;
696 }
697
698 /**
699  *      setup_irq - setup an interrupt
700  *      @irq: Interrupt line to setup
701  *      @act: irqaction for the interrupt
702  *
703  * Used to statically setup interrupts in the early boot process.
704  */
705 int setup_irq(unsigned int irq, struct irqaction *act)
706 {
707         struct irq_desc *desc = irq_to_desc(irq);
708
709         return __setup_irq(irq, desc, act);
710 }
711 EXPORT_SYMBOL_GPL(setup_irq);
712
713  /*
714  * Internal function to unregister an irqaction - used to free
715  * regular and special interrupts that are part of the architecture.
716  */
717 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
718 {
719         struct irq_desc *desc = irq_to_desc(irq);
720         struct irqaction *action, **action_ptr;
721         struct task_struct *irqthread;
722         unsigned long flags;
723
724         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
725
726         if (!desc)
727                 return NULL;
728
729         spin_lock_irqsave(&desc->lock, flags);
730
731         /*
732          * There can be multiple actions per IRQ descriptor, find the right
733          * one based on the dev_id:
734          */
735         action_ptr = &desc->action;
736         for (;;) {
737                 action = *action_ptr;
738
739                 if (!action) {
740                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
741                         spin_unlock_irqrestore(&desc->lock, flags);
742
743                         return NULL;
744                 }
745
746                 if (action->dev_id == dev_id)
747                         break;
748                 action_ptr = &action->next;
749         }
750
751         /* Found it - now remove it from the list of entries: */
752         *action_ptr = action->next;
753
754         /* Currently used only by UML, might disappear one day: */
755 #ifdef CONFIG_IRQ_RELEASE_METHOD
756         if (desc->chip->release)
757                 desc->chip->release(irq, dev_id);
758 #endif
759
760         /* If this was the last handler, shut down the IRQ line: */
761         if (!desc->action) {
762                 desc->status |= IRQ_DISABLED;
763                 if (desc->chip->shutdown)
764                         desc->chip->shutdown(irq);
765                 else
766                         desc->chip->disable(irq);
767         }
768
769         irqthread = action->thread;
770         action->thread = NULL;
771
772         spin_unlock_irqrestore(&desc->lock, flags);
773
774         unregister_handler_proc(irq, action);
775
776         /* Make sure it's not being used on another CPU: */
777         synchronize_irq(irq);
778
779         if (irqthread) {
780                 if (!test_bit(IRQTF_DIED, &action->thread_flags))
781                         kthread_stop(irqthread);
782                 put_task_struct(irqthread);
783         }
784
785 #ifdef CONFIG_DEBUG_SHIRQ
786         /*
787          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
788          * event to happen even now it's being freed, so let's make sure that
789          * is so by doing an extra call to the handler ....
790          *
791          * ( We do this after actually deregistering it, to make sure that a
792          *   'real' IRQ doesn't run in * parallel with our fake. )
793          */
794         if (action->flags & IRQF_SHARED) {
795                 local_irq_save(flags);
796                 action->handler(irq, dev_id);
797                 local_irq_restore(flags);
798         }
799 #endif
800         return action;
801 }
802
803 /**
804  *      remove_irq - free an interrupt
805  *      @irq: Interrupt line to free
806  *      @act: irqaction for the interrupt
807  *
808  * Used to remove interrupts statically setup by the early boot process.
809  */
810 void remove_irq(unsigned int irq, struct irqaction *act)
811 {
812         __free_irq(irq, act->dev_id);
813 }
814 EXPORT_SYMBOL_GPL(remove_irq);
815
816 /**
817  *      free_irq - free an interrupt allocated with request_irq
818  *      @irq: Interrupt line to free
819  *      @dev_id: Device identity to free
820  *
821  *      Remove an interrupt handler. The handler is removed and if the
822  *      interrupt line is no longer in use by any driver it is disabled.
823  *      On a shared IRQ the caller must ensure the interrupt is disabled
824  *      on the card it drives before calling this function. The function
825  *      does not return until any executing interrupts for this IRQ
826  *      have completed.
827  *
828  *      This function must not be called from interrupt context.
829  */
830 void free_irq(unsigned int irq, void *dev_id)
831 {
832         kfree(__free_irq(irq, dev_id));
833 }
834 EXPORT_SYMBOL(free_irq);
835
836 /**
837  *      request_threaded_irq - allocate an interrupt line
838  *      @irq: Interrupt line to allocate
839  *      @handler: Function to be called when the IRQ occurs.
840  *                Primary handler for threaded interrupts
841  *      @thread_fn: Function called from the irq handler thread
842  *                  If NULL, no irq thread is created
843  *      @irqflags: Interrupt type flags
844  *      @devname: An ascii name for the claiming device
845  *      @dev_id: A cookie passed back to the handler function
846  *
847  *      This call allocates interrupt resources and enables the
848  *      interrupt line and IRQ handling. From the point this
849  *      call is made your handler function may be invoked. Since
850  *      your handler function must clear any interrupt the board
851  *      raises, you must take care both to initialise your hardware
852  *      and to set up the interrupt handler in the right order.
853  *
854  *      If you want to set up a threaded irq handler for your device
855  *      then you need to supply @handler and @thread_fn. @handler ist
856  *      still called in hard interrupt context and has to check
857  *      whether the interrupt originates from the device. If yes it
858  *      needs to disable the interrupt on the device and return
859  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
860  *      @thread_fn. This split handler design is necessary to support
861  *      shared interrupts.
862  *
863  *      Dev_id must be globally unique. Normally the address of the
864  *      device data structure is used as the cookie. Since the handler
865  *      receives this value it makes sense to use it.
866  *
867  *      If your interrupt is shared you must pass a non NULL dev_id
868  *      as this is required when freeing the interrupt.
869  *
870  *      Flags:
871  *
872  *      IRQF_SHARED             Interrupt is shared
873  *      IRQF_DISABLED   Disable local interrupts while processing
874  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
875  *      IRQF_TRIGGER_*          Specify active edge(s) or level
876  *
877  */
878 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
879                          irq_handler_t thread_fn, unsigned long irqflags,
880                          const char *devname, void *dev_id)
881 {
882         struct irqaction *action;
883         struct irq_desc *desc;
884         int retval;
885
886         /*
887          * handle_IRQ_event() always ignores IRQF_DISABLED except for
888          * the _first_ irqaction (sigh).  That can cause oopsing, but
889          * the behavior is classified as "will not fix" so we need to
890          * start nudging drivers away from using that idiom.
891          */
892         if ((irqflags & (IRQF_SHARED|IRQF_DISABLED)) ==
893                                         (IRQF_SHARED|IRQF_DISABLED)) {
894                 pr_warning(
895                   "IRQ %d/%s: IRQF_DISABLED is not guaranteed on shared IRQs\n",
896                         irq, devname);
897         }
898
899 #ifdef CONFIG_LOCKDEP
900         /*
901          * Lockdep wants atomic interrupt handlers:
902          */
903         irqflags |= IRQF_DISABLED;
904 #endif
905         /*
906          * Sanity-check: shared interrupts must pass in a real dev-ID,
907          * otherwise we'll have trouble later trying to figure out
908          * which interrupt is which (messes up the interrupt freeing
909          * logic etc).
910          */
911         if ((irqflags & IRQF_SHARED) && !dev_id)
912                 return -EINVAL;
913
914         desc = irq_to_desc(irq);
915         if (!desc)
916                 return -EINVAL;
917
918         if (desc->status & IRQ_NOREQUEST)
919                 return -EINVAL;
920         if (!handler)
921                 return -EINVAL;
922
923         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
924         if (!action)
925                 return -ENOMEM;
926
927         action->handler = handler;
928         action->thread_fn = thread_fn;
929         action->flags = irqflags;
930         action->name = devname;
931         action->dev_id = dev_id;
932
933         retval = __setup_irq(irq, desc, action);
934         if (retval)
935                 kfree(action);
936
937 #ifdef CONFIG_DEBUG_SHIRQ
938         if (irqflags & IRQF_SHARED) {
939                 /*
940                  * It's a shared IRQ -- the driver ought to be prepared for it
941                  * to happen immediately, so let's make sure....
942                  * We disable the irq to make sure that a 'real' IRQ doesn't
943                  * run in parallel with our fake.
944                  */
945                 unsigned long flags;
946
947                 disable_irq(irq);
948                 local_irq_save(flags);
949
950                 handler(irq, dev_id);
951
952                 local_irq_restore(flags);
953                 enable_irq(irq);
954         }
955 #endif
956         return retval;
957 }
958 EXPORT_SYMBOL(request_threaded_irq);