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