Merge branch 'irq/urgent' into irq/core
[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                 raw_spin_lock_irqsave(&desc->lock, flags);
50                 status = desc->status;
51                 raw_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->irq_data.chip ||
77             !desc->irq_data.chip->irq_set_affinity)
78                 return 0;
79
80         return 1;
81 }
82
83 /**
84  *      irq_set_thread_affinity - Notify irq threads to adjust affinity
85  *      @desc:          irq descriptor which has affitnity changed
86  *
87  *      We just set IRQTF_AFFINITY and delegate the affinity setting
88  *      to the interrupt thread itself. We can not call
89  *      set_cpus_allowed_ptr() here as we hold desc->lock and this
90  *      code can be called from hard interrupt context.
91  */
92 void irq_set_thread_affinity(struct irq_desc *desc)
93 {
94         struct irqaction *action = desc->action;
95
96         while (action) {
97                 if (action->thread)
98                         set_bit(IRQTF_AFFINITY, &action->thread_flags);
99                 action = action->next;
100         }
101 }
102
103 /**
104  *      irq_set_affinity - Set the irq affinity of a given irq
105  *      @irq:           Interrupt to set affinity
106  *      @cpumask:       cpumask
107  *
108  */
109 int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
110 {
111         struct irq_desc *desc = irq_to_desc(irq);
112         struct irq_chip *chip = desc->irq_data.chip;
113         unsigned long flags;
114
115         if (!chip->irq_set_affinity)
116                 return -EINVAL;
117
118         raw_spin_lock_irqsave(&desc->lock, flags);
119
120 #ifdef CONFIG_GENERIC_PENDING_IRQ
121         if (desc->status & IRQ_MOVE_PCNTXT) {
122                 if (!chip->irq_set_affinity(&desc->irq_data, cpumask, false)) {
123                         cpumask_copy(desc->irq_data.affinity, cpumask);
124                         irq_set_thread_affinity(desc);
125                 }
126         }
127         else {
128                 desc->status |= IRQ_MOVE_PENDING;
129                 cpumask_copy(desc->pending_mask, cpumask);
130         }
131 #else
132         if (!chip->irq_set_affinity(&desc->irq_data, cpumask, false)) {
133                 cpumask_copy(desc->irq_data.affinity, cpumask);
134                 irq_set_thread_affinity(desc);
135         }
136 #endif
137         if (desc->affinity_notify) {
138                 kref_get(&desc->affinity_notify->kref);
139                 schedule_work(&desc->affinity_notify->work);
140         }
141         desc->status |= IRQ_AFFINITY_SET;
142         raw_spin_unlock_irqrestore(&desc->lock, flags);
143         return 0;
144 }
145
146 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
147 {
148         struct irq_desc *desc = irq_to_desc(irq);
149         unsigned long flags;
150
151         if (!desc)
152                 return -EINVAL;
153
154         raw_spin_lock_irqsave(&desc->lock, flags);
155         desc->affinity_hint = m;
156         raw_spin_unlock_irqrestore(&desc->lock, flags);
157
158         return 0;
159 }
160 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
161
162 static void irq_affinity_notify(struct work_struct *work)
163 {
164         struct irq_affinity_notify *notify =
165                 container_of(work, struct irq_affinity_notify, work);
166         struct irq_desc *desc = irq_to_desc(notify->irq);
167         cpumask_var_t cpumask;
168         unsigned long flags;
169
170         if (!desc)
171                 goto out;
172
173         if (!alloc_cpumask_var(&cpumask, GFP_KERNEL))
174                 goto out;
175
176         raw_spin_lock_irqsave(&desc->lock, flags);
177 #ifdef CONFIG_GENERIC_PENDING_IRQ
178         if (desc->status & IRQ_MOVE_PENDING)
179                 cpumask_copy(cpumask, desc->pending_mask);
180         else
181 #endif
182                 cpumask_copy(cpumask, desc->irq_data.affinity);
183         raw_spin_unlock_irqrestore(&desc->lock, flags);
184
185         notify->notify(notify, cpumask);
186
187         free_cpumask_var(cpumask);
188 out:
189         kref_put(&notify->kref, notify->release);
190 }
191
192 /**
193  *      irq_set_affinity_notifier - control notification of IRQ affinity changes
194  *      @irq:           Interrupt for which to enable/disable notification
195  *      @notify:        Context for notification, or %NULL to disable
196  *                      notification.  Function pointers must be initialised;
197  *                      the other fields will be initialised by this function.
198  *
199  *      Must be called in process context.  Notification may only be enabled
200  *      after the IRQ is allocated and must be disabled before the IRQ is
201  *      freed using free_irq().
202  */
203 int
204 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
205 {
206         struct irq_desc *desc = irq_to_desc(irq);
207         struct irq_affinity_notify *old_notify;
208         unsigned long flags;
209
210         /* The release function is promised process context */
211         might_sleep();
212
213         if (!desc)
214                 return -EINVAL;
215
216         /* Complete initialisation of *notify */
217         if (notify) {
218                 notify->irq = irq;
219                 kref_init(&notify->kref);
220                 INIT_WORK(&notify->work, irq_affinity_notify);
221         }
222
223         raw_spin_lock_irqsave(&desc->lock, flags);
224         old_notify = desc->affinity_notify;
225         desc->affinity_notify = notify;
226         raw_spin_unlock_irqrestore(&desc->lock, flags);
227
228         if (old_notify)
229                 kref_put(&old_notify->kref, old_notify->release);
230
231         return 0;
232 }
233 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
234
235 #ifndef CONFIG_AUTO_IRQ_AFFINITY
236 /*
237  * Generic version of the affinity autoselector.
238  */
239 static int setup_affinity(unsigned int irq, struct irq_desc *desc)
240 {
241         if (!irq_can_set_affinity(irq))
242                 return 0;
243
244         /*
245          * Preserve an userspace affinity setup, but make sure that
246          * one of the targets is online.
247          */
248         if (desc->status & (IRQ_AFFINITY_SET | IRQ_NO_BALANCING)) {
249                 if (cpumask_any_and(desc->irq_data.affinity, cpu_online_mask)
250                     < nr_cpu_ids)
251                         goto set_affinity;
252                 else
253                         desc->status &= ~IRQ_AFFINITY_SET;
254         }
255
256         cpumask_and(desc->irq_data.affinity, cpu_online_mask, irq_default_affinity);
257 set_affinity:
258         desc->irq_data.chip->irq_set_affinity(&desc->irq_data, desc->irq_data.affinity, false);
259
260         return 0;
261 }
262 #else
263 static inline int setup_affinity(unsigned int irq, struct irq_desc *d)
264 {
265         return irq_select_affinity(irq);
266 }
267 #endif
268
269 /*
270  * Called when affinity is set via /proc/irq
271  */
272 int irq_select_affinity_usr(unsigned int irq)
273 {
274         struct irq_desc *desc = irq_to_desc(irq);
275         unsigned long flags;
276         int ret;
277
278         raw_spin_lock_irqsave(&desc->lock, flags);
279         ret = setup_affinity(irq, desc);
280         if (!ret)
281                 irq_set_thread_affinity(desc);
282         raw_spin_unlock_irqrestore(&desc->lock, flags);
283
284         return ret;
285 }
286
287 #else
288 static inline int setup_affinity(unsigned int irq, struct irq_desc *desc)
289 {
290         return 0;
291 }
292 #endif
293
294 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
295 {
296         if (suspend) {
297                 if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
298                         return;
299                 desc->status |= IRQ_SUSPENDED;
300         }
301
302         if (!desc->depth++) {
303                 desc->status |= IRQ_DISABLED;
304                 desc->irq_data.chip->irq_disable(&desc->irq_data);
305         }
306 }
307
308 /**
309  *      disable_irq_nosync - disable an irq without waiting
310  *      @irq: Interrupt to disable
311  *
312  *      Disable the selected interrupt line.  Disables and Enables are
313  *      nested.
314  *      Unlike disable_irq(), this function does not ensure existing
315  *      instances of the IRQ handler have completed before returning.
316  *
317  *      This function may be called from IRQ context.
318  */
319 void disable_irq_nosync(unsigned int irq)
320 {
321         struct irq_desc *desc = irq_to_desc(irq);
322         unsigned long flags;
323
324         if (!desc)
325                 return;
326
327         chip_bus_lock(desc);
328         raw_spin_lock_irqsave(&desc->lock, flags);
329         __disable_irq(desc, irq, false);
330         raw_spin_unlock_irqrestore(&desc->lock, flags);
331         chip_bus_sync_unlock(desc);
332 }
333 EXPORT_SYMBOL(disable_irq_nosync);
334
335 /**
336  *      disable_irq - disable an irq and wait for completion
337  *      @irq: Interrupt to disable
338  *
339  *      Disable the selected interrupt line.  Enables and Disables are
340  *      nested.
341  *      This function waits for any pending IRQ handlers for this interrupt
342  *      to complete before returning. If you use this function while
343  *      holding a resource the IRQ handler may need you will deadlock.
344  *
345  *      This function may be called - with care - from IRQ context.
346  */
347 void disable_irq(unsigned int irq)
348 {
349         struct irq_desc *desc = irq_to_desc(irq);
350
351         if (!desc)
352                 return;
353
354         disable_irq_nosync(irq);
355         if (desc->action)
356                 synchronize_irq(irq);
357 }
358 EXPORT_SYMBOL(disable_irq);
359
360 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
361 {
362         if (resume) {
363                 if (!(desc->status & IRQ_SUSPENDED)) {
364                         if (!desc->action)
365                                 return;
366                         if (!(desc->action->flags & IRQF_FORCE_RESUME))
367                                 return;
368                         /* Pretend that it got disabled ! */
369                         desc->depth++;
370                 }
371                 desc->status &= ~IRQ_SUSPENDED;
372         }
373
374         switch (desc->depth) {
375         case 0:
376  err_out:
377                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
378                 break;
379         case 1: {
380                 unsigned int status = desc->status & ~IRQ_DISABLED;
381
382                 if (desc->status & IRQ_SUSPENDED)
383                         goto err_out;
384                 /* Prevent probing on this irq: */
385                 desc->status = status | IRQ_NOPROBE;
386                 check_irq_resend(desc, irq);
387                 /* fall-through */
388         }
389         default:
390                 desc->depth--;
391         }
392 }
393
394 /**
395  *      enable_irq - enable handling of an irq
396  *      @irq: Interrupt to enable
397  *
398  *      Undoes the effect of one call to disable_irq().  If this
399  *      matches the last disable, processing of interrupts on this
400  *      IRQ line is re-enabled.
401  *
402  *      This function may be called from IRQ context only when
403  *      desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
404  */
405 void enable_irq(unsigned int irq)
406 {
407         struct irq_desc *desc = irq_to_desc(irq);
408         unsigned long flags;
409
410         if (!desc)
411                 return;
412
413         if (WARN(!desc->irq_data.chip || !desc->irq_data.chip->irq_enable,
414             KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
415                 return;
416
417         chip_bus_lock(desc);
418         raw_spin_lock_irqsave(&desc->lock, flags);
419         __enable_irq(desc, irq, false);
420         raw_spin_unlock_irqrestore(&desc->lock, flags);
421         chip_bus_sync_unlock(desc);
422 }
423 EXPORT_SYMBOL(enable_irq);
424
425 static int set_irq_wake_real(unsigned int irq, unsigned int on)
426 {
427         struct irq_desc *desc = irq_to_desc(irq);
428         int ret = -ENXIO;
429
430         if (desc->irq_data.chip->irq_set_wake)
431                 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
432
433         return ret;
434 }
435
436 /**
437  *      set_irq_wake - control irq power management wakeup
438  *      @irq:   interrupt to control
439  *      @on:    enable/disable power management wakeup
440  *
441  *      Enable/disable power management wakeup mode, which is
442  *      disabled by default.  Enables and disables must match,
443  *      just as they match for non-wakeup mode support.
444  *
445  *      Wakeup mode lets this IRQ wake the system from sleep
446  *      states like "suspend to RAM".
447  */
448 int set_irq_wake(unsigned int irq, unsigned int on)
449 {
450         struct irq_desc *desc = irq_to_desc(irq);
451         unsigned long flags;
452         int ret = 0;
453
454         /* wakeup-capable irqs can be shared between drivers that
455          * don't need to have the same sleep mode behaviors.
456          */
457         raw_spin_lock_irqsave(&desc->lock, flags);
458         if (on) {
459                 if (desc->wake_depth++ == 0) {
460                         ret = set_irq_wake_real(irq, on);
461                         if (ret)
462                                 desc->wake_depth = 0;
463                         else
464                                 desc->status |= IRQ_WAKEUP;
465                 }
466         } else {
467                 if (desc->wake_depth == 0) {
468                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
469                 } else if (--desc->wake_depth == 0) {
470                         ret = set_irq_wake_real(irq, on);
471                         if (ret)
472                                 desc->wake_depth = 1;
473                         else
474                                 desc->status &= ~IRQ_WAKEUP;
475                 }
476         }
477
478         raw_spin_unlock_irqrestore(&desc->lock, flags);
479         return ret;
480 }
481 EXPORT_SYMBOL(set_irq_wake);
482
483 /*
484  * Internal function that tells the architecture code whether a
485  * particular irq has been exclusively allocated or is available
486  * for driver use.
487  */
488 int can_request_irq(unsigned int irq, unsigned long irqflags)
489 {
490         struct irq_desc *desc = irq_to_desc(irq);
491         struct irqaction *action;
492         unsigned long flags;
493
494         if (!desc)
495                 return 0;
496
497         if (desc->status & IRQ_NOREQUEST)
498                 return 0;
499
500         raw_spin_lock_irqsave(&desc->lock, flags);
501         action = desc->action;
502         if (action)
503                 if (irqflags & action->flags & IRQF_SHARED)
504                         action = NULL;
505
506         raw_spin_unlock_irqrestore(&desc->lock, flags);
507
508         return !action;
509 }
510
511 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
512 {
513         /*
514          * If the architecture still has not overriden
515          * the flow handler then zap the default. This
516          * should catch incorrect flow-type setting.
517          */
518         if (desc->handle_irq == &handle_bad_irq)
519                 desc->handle_irq = NULL;
520 }
521
522 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
523                       unsigned long flags)
524 {
525         int ret;
526         struct irq_chip *chip = desc->irq_data.chip;
527
528         if (!chip || !chip->irq_set_type) {
529                 /*
530                  * IRQF_TRIGGER_* but the PIC does not support multiple
531                  * flow-types?
532                  */
533                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
534                                 chip ? (chip->name ? : "unknown") : "unknown");
535                 return 0;
536         }
537
538         /* caller masked out all except trigger mode flags */
539         ret = chip->irq_set_type(&desc->irq_data, flags);
540
541         if (ret)
542                 pr_err("setting trigger mode %lu for irq %u failed (%pF)\n",
543                        flags, irq, chip->irq_set_type);
544         else {
545                 if (flags & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
546                         flags |= IRQ_LEVEL;
547                 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
548                 desc->status &= ~(IRQ_LEVEL | IRQ_TYPE_SENSE_MASK);
549                 desc->status |= flags;
550
551                 if (chip != desc->irq_data.chip)
552                         irq_chip_set_defaults(desc->irq_data.chip);
553         }
554
555         return ret;
556 }
557
558 /*
559  * Default primary interrupt handler for threaded interrupts. Is
560  * assigned as primary handler when request_threaded_irq is called
561  * with handler == NULL. Useful for oneshot interrupts.
562  */
563 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
564 {
565         return IRQ_WAKE_THREAD;
566 }
567
568 /*
569  * Primary handler for nested threaded interrupts. Should never be
570  * called.
571  */
572 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
573 {
574         WARN(1, "Primary handler called for nested irq %d\n", irq);
575         return IRQ_NONE;
576 }
577
578 static int irq_wait_for_interrupt(struct irqaction *action)
579 {
580         while (!kthread_should_stop()) {
581                 set_current_state(TASK_INTERRUPTIBLE);
582
583                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
584                                        &action->thread_flags)) {
585                         __set_current_state(TASK_RUNNING);
586                         return 0;
587                 }
588                 schedule();
589         }
590         return -1;
591 }
592
593 /*
594  * Oneshot interrupts keep the irq line masked until the threaded
595  * handler finished. unmask if the interrupt has not been disabled and
596  * is marked MASKED.
597  */
598 static void irq_finalize_oneshot(unsigned int irq, struct irq_desc *desc)
599 {
600 again:
601         chip_bus_lock(desc);
602         raw_spin_lock_irq(&desc->lock);
603
604         /*
605          * Implausible though it may be we need to protect us against
606          * the following scenario:
607          *
608          * The thread is faster done than the hard interrupt handler
609          * on the other CPU. If we unmask the irq line then the
610          * interrupt can come in again and masks the line, leaves due
611          * to IRQ_INPROGRESS and the irq line is masked forever.
612          */
613         if (unlikely(desc->status & IRQ_INPROGRESS)) {
614                 raw_spin_unlock_irq(&desc->lock);
615                 chip_bus_sync_unlock(desc);
616                 cpu_relax();
617                 goto again;
618         }
619
620         if (!(desc->status & IRQ_DISABLED) && (desc->status & IRQ_MASKED)) {
621                 desc->status &= ~IRQ_MASKED;
622                 desc->irq_data.chip->irq_unmask(&desc->irq_data);
623         }
624         raw_spin_unlock_irq(&desc->lock);
625         chip_bus_sync_unlock(desc);
626 }
627
628 #ifdef CONFIG_SMP
629 /*
630  * Check whether we need to change the affinity of the interrupt thread.
631  */
632 static void
633 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
634 {
635         cpumask_var_t mask;
636
637         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
638                 return;
639
640         /*
641          * In case we are out of memory we set IRQTF_AFFINITY again and
642          * try again next time
643          */
644         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
645                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
646                 return;
647         }
648
649         raw_spin_lock_irq(&desc->lock);
650         cpumask_copy(mask, desc->irq_data.affinity);
651         raw_spin_unlock_irq(&desc->lock);
652
653         set_cpus_allowed_ptr(current, mask);
654         free_cpumask_var(mask);
655 }
656 #else
657 static inline void
658 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
659 #endif
660
661 /*
662  * Interrupt handler thread
663  */
664 static int irq_thread(void *data)
665 {
666         static const struct sched_param param = {
667                 .sched_priority = MAX_USER_RT_PRIO/2,
668         };
669         struct irqaction *action = data;
670         struct irq_desc *desc = irq_to_desc(action->irq);
671         int wake, oneshot = desc->status & IRQ_ONESHOT;
672
673         sched_setscheduler(current, SCHED_FIFO, &param);
674         current->irqaction = action;
675
676         while (!irq_wait_for_interrupt(action)) {
677
678                 irq_thread_check_affinity(desc, action);
679
680                 atomic_inc(&desc->threads_active);
681
682                 raw_spin_lock_irq(&desc->lock);
683                 if (unlikely(desc->status & IRQ_DISABLED)) {
684                         /*
685                          * CHECKME: We might need a dedicated
686                          * IRQ_THREAD_PENDING flag here, which
687                          * retriggers the thread in check_irq_resend()
688                          * but AFAICT IRQ_PENDING should be fine as it
689                          * retriggers the interrupt itself --- tglx
690                          */
691                         desc->status |= IRQ_PENDING;
692                         raw_spin_unlock_irq(&desc->lock);
693                 } else {
694                         raw_spin_unlock_irq(&desc->lock);
695
696                         action->thread_fn(action->irq, action->dev_id);
697
698                         if (oneshot)
699                                 irq_finalize_oneshot(action->irq, desc);
700                 }
701
702                 wake = atomic_dec_and_test(&desc->threads_active);
703
704                 if (wake && waitqueue_active(&desc->wait_for_threads))
705                         wake_up(&desc->wait_for_threads);
706         }
707
708         /*
709          * Clear irqaction. Otherwise exit_irq_thread() would make
710          * fuzz about an active irq thread going into nirvana.
711          */
712         current->irqaction = NULL;
713         return 0;
714 }
715
716 /*
717  * Called from do_exit()
718  */
719 void exit_irq_thread(void)
720 {
721         struct task_struct *tsk = current;
722
723         if (!tsk->irqaction)
724                 return;
725
726         printk(KERN_ERR
727                "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
728                tsk->comm ? tsk->comm : "", tsk->pid, tsk->irqaction->irq);
729
730         /*
731          * Set the THREAD DIED flag to prevent further wakeups of the
732          * soon to be gone threaded handler.
733          */
734         set_bit(IRQTF_DIED, &tsk->irqaction->flags);
735 }
736
737 /*
738  * Internal function to register an irqaction - typically used to
739  * allocate special interrupts that are part of the architecture.
740  */
741 static int
742 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
743 {
744         struct irqaction *old, **old_ptr;
745         const char *old_name = NULL;
746         unsigned long flags;
747         int nested, shared = 0;
748         int ret;
749
750         if (!desc)
751                 return -EINVAL;
752
753         if (desc->irq_data.chip == &no_irq_chip)
754                 return -ENOSYS;
755         /*
756          * Some drivers like serial.c use request_irq() heavily,
757          * so we have to be careful not to interfere with a
758          * running system.
759          */
760         if (new->flags & IRQF_SAMPLE_RANDOM) {
761                 /*
762                  * This function might sleep, we want to call it first,
763                  * outside of the atomic block.
764                  * Yes, this might clear the entropy pool if the wrong
765                  * driver is attempted to be loaded, without actually
766                  * installing a new handler, but is this really a problem,
767                  * only the sysadmin is able to do this.
768                  */
769                 rand_initialize_irq(irq);
770         }
771
772         /* Oneshot interrupts are not allowed with shared */
773         if ((new->flags & IRQF_ONESHOT) && (new->flags & IRQF_SHARED))
774                 return -EINVAL;
775
776         /*
777          * Check whether the interrupt nests into another interrupt
778          * thread.
779          */
780         nested = desc->status & IRQ_NESTED_THREAD;
781         if (nested) {
782                 if (!new->thread_fn)
783                         return -EINVAL;
784                 /*
785                  * Replace the primary handler which was provided from
786                  * the driver for non nested interrupt handling by the
787                  * dummy function which warns when called.
788                  */
789                 new->handler = irq_nested_primary_handler;
790         }
791
792         /*
793          * Create a handler thread when a thread function is supplied
794          * and the interrupt does not nest into another interrupt
795          * thread.
796          */
797         if (new->thread_fn && !nested) {
798                 struct task_struct *t;
799
800                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
801                                    new->name);
802                 if (IS_ERR(t))
803                         return PTR_ERR(t);
804                 /*
805                  * We keep the reference to the task struct even if
806                  * the thread dies to avoid that the interrupt code
807                  * references an already freed task_struct.
808                  */
809                 get_task_struct(t);
810                 new->thread = t;
811         }
812
813         /*
814          * The following block of code has to be executed atomically
815          */
816         raw_spin_lock_irqsave(&desc->lock, flags);
817         old_ptr = &desc->action;
818         old = *old_ptr;
819         if (old) {
820                 /*
821                  * Can't share interrupts unless both agree to and are
822                  * the same type (level, edge, polarity). So both flag
823                  * fields must have IRQF_SHARED set and the bits which
824                  * set the trigger type must match.
825                  */
826                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
827                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
828                         old_name = old->name;
829                         goto mismatch;
830                 }
831
832 #if defined(CONFIG_IRQ_PER_CPU)
833                 /* All handlers must agree on per-cpuness */
834                 if ((old->flags & IRQF_PERCPU) !=
835                     (new->flags & IRQF_PERCPU))
836                         goto mismatch;
837 #endif
838
839                 /* add new interrupt at end of irq queue */
840                 do {
841                         old_ptr = &old->next;
842                         old = *old_ptr;
843                 } while (old);
844                 shared = 1;
845         }
846
847         if (!shared) {
848                 irq_chip_set_defaults(desc->irq_data.chip);
849
850                 init_waitqueue_head(&desc->wait_for_threads);
851
852                 /* Setup the type (level, edge polarity) if configured: */
853                 if (new->flags & IRQF_TRIGGER_MASK) {
854                         ret = __irq_set_trigger(desc, irq,
855                                         new->flags & IRQF_TRIGGER_MASK);
856
857                         if (ret)
858                                 goto out_thread;
859                 } else
860                         compat_irq_chip_set_default_handler(desc);
861 #if defined(CONFIG_IRQ_PER_CPU)
862                 if (new->flags & IRQF_PERCPU)
863                         desc->status |= IRQ_PER_CPU;
864 #endif
865
866                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING | IRQ_ONESHOT |
867                                   IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
868
869                 if (new->flags & IRQF_ONESHOT)
870                         desc->status |= IRQ_ONESHOT;
871
872                 if (!(desc->status & IRQ_NOAUTOEN)) {
873                         desc->depth = 0;
874                         desc->status &= ~IRQ_DISABLED;
875                         desc->irq_data.chip->irq_startup(&desc->irq_data);
876                 } else
877                         /* Undo nested disables: */
878                         desc->depth = 1;
879
880                 /* Exclude IRQ from balancing if requested */
881                 if (new->flags & IRQF_NOBALANCING)
882                         desc->status |= IRQ_NO_BALANCING;
883
884                 /* Set default affinity mask once everything is setup */
885                 setup_affinity(irq, desc);
886
887         } else if ((new->flags & IRQF_TRIGGER_MASK)
888                         && (new->flags & IRQF_TRIGGER_MASK)
889                                 != (desc->status & IRQ_TYPE_SENSE_MASK)) {
890                 /* hope the handler works with the actual trigger mode... */
891                 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
892                                 irq, (int)(desc->status & IRQ_TYPE_SENSE_MASK),
893                                 (int)(new->flags & IRQF_TRIGGER_MASK));
894         }
895
896         new->irq = irq;
897         *old_ptr = new;
898
899         /* Reset broken irq detection when installing new handler */
900         desc->irq_count = 0;
901         desc->irqs_unhandled = 0;
902
903         /*
904          * Check whether we disabled the irq via the spurious handler
905          * before. Reenable it and give it another chance.
906          */
907         if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
908                 desc->status &= ~IRQ_SPURIOUS_DISABLED;
909                 __enable_irq(desc, irq, false);
910         }
911
912         raw_spin_unlock_irqrestore(&desc->lock, flags);
913
914         /*
915          * Strictly no need to wake it up, but hung_task complains
916          * when no hard interrupt wakes the thread up.
917          */
918         if (new->thread)
919                 wake_up_process(new->thread);
920
921         register_irq_proc(irq, desc);
922         new->dir = NULL;
923         register_handler_proc(irq, new);
924
925         return 0;
926
927 mismatch:
928 #ifdef CONFIG_DEBUG_SHIRQ
929         if (!(new->flags & IRQF_PROBE_SHARED)) {
930                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
931                 if (old_name)
932                         printk(KERN_ERR "current handler: %s\n", old_name);
933                 dump_stack();
934         }
935 #endif
936         ret = -EBUSY;
937
938 out_thread:
939         raw_spin_unlock_irqrestore(&desc->lock, flags);
940         if (new->thread) {
941                 struct task_struct *t = new->thread;
942
943                 new->thread = NULL;
944                 if (likely(!test_bit(IRQTF_DIED, &new->thread_flags)))
945                         kthread_stop(t);
946                 put_task_struct(t);
947         }
948         return ret;
949 }
950
951 /**
952  *      setup_irq - setup an interrupt
953  *      @irq: Interrupt line to setup
954  *      @act: irqaction for the interrupt
955  *
956  * Used to statically setup interrupts in the early boot process.
957  */
958 int setup_irq(unsigned int irq, struct irqaction *act)
959 {
960         int retval;
961         struct irq_desc *desc = irq_to_desc(irq);
962
963         chip_bus_lock(desc);
964         retval = __setup_irq(irq, desc, act);
965         chip_bus_sync_unlock(desc);
966
967         return retval;
968 }
969 EXPORT_SYMBOL_GPL(setup_irq);
970
971  /*
972  * Internal function to unregister an irqaction - used to free
973  * regular and special interrupts that are part of the architecture.
974  */
975 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
976 {
977         struct irq_desc *desc = irq_to_desc(irq);
978         struct irqaction *action, **action_ptr;
979         unsigned long flags;
980
981         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
982
983         if (!desc)
984                 return NULL;
985
986         raw_spin_lock_irqsave(&desc->lock, flags);
987
988         /*
989          * There can be multiple actions per IRQ descriptor, find the right
990          * one based on the dev_id:
991          */
992         action_ptr = &desc->action;
993         for (;;) {
994                 action = *action_ptr;
995
996                 if (!action) {
997                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
998                         raw_spin_unlock_irqrestore(&desc->lock, flags);
999
1000                         return NULL;
1001                 }
1002
1003                 if (action->dev_id == dev_id)
1004                         break;
1005                 action_ptr = &action->next;
1006         }
1007
1008         /* Found it - now remove it from the list of entries: */
1009         *action_ptr = action->next;
1010
1011         /* Currently used only by UML, might disappear one day: */
1012 #ifdef CONFIG_IRQ_RELEASE_METHOD
1013         if (desc->irq_data.chip->release)
1014                 desc->irq_data.chip->release(irq, dev_id);
1015 #endif
1016
1017         /* If this was the last handler, shut down the IRQ line: */
1018         if (!desc->action) {
1019                 desc->status |= IRQ_DISABLED;
1020                 if (desc->irq_data.chip->irq_shutdown)
1021                         desc->irq_data.chip->irq_shutdown(&desc->irq_data);
1022                 else
1023                         desc->irq_data.chip->irq_disable(&desc->irq_data);
1024         }
1025
1026 #ifdef CONFIG_SMP
1027         /* make sure affinity_hint is cleaned up */
1028         if (WARN_ON_ONCE(desc->affinity_hint))
1029                 desc->affinity_hint = NULL;
1030 #endif
1031
1032         raw_spin_unlock_irqrestore(&desc->lock, flags);
1033
1034         unregister_handler_proc(irq, action);
1035
1036         /* Make sure it's not being used on another CPU: */
1037         synchronize_irq(irq);
1038
1039 #ifdef CONFIG_DEBUG_SHIRQ
1040         /*
1041          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1042          * event to happen even now it's being freed, so let's make sure that
1043          * is so by doing an extra call to the handler ....
1044          *
1045          * ( We do this after actually deregistering it, to make sure that a
1046          *   'real' IRQ doesn't run in * parallel with our fake. )
1047          */
1048         if (action->flags & IRQF_SHARED) {
1049                 local_irq_save(flags);
1050                 action->handler(irq, dev_id);
1051                 local_irq_restore(flags);
1052         }
1053 #endif
1054
1055         if (action->thread) {
1056                 if (!test_bit(IRQTF_DIED, &action->thread_flags))
1057                         kthread_stop(action->thread);
1058                 put_task_struct(action->thread);
1059         }
1060
1061         return action;
1062 }
1063
1064 /**
1065  *      remove_irq - free an interrupt
1066  *      @irq: Interrupt line to free
1067  *      @act: irqaction for the interrupt
1068  *
1069  * Used to remove interrupts statically setup by the early boot process.
1070  */
1071 void remove_irq(unsigned int irq, struct irqaction *act)
1072 {
1073         __free_irq(irq, act->dev_id);
1074 }
1075 EXPORT_SYMBOL_GPL(remove_irq);
1076
1077 /**
1078  *      free_irq - free an interrupt allocated with request_irq
1079  *      @irq: Interrupt line to free
1080  *      @dev_id: Device identity to free
1081  *
1082  *      Remove an interrupt handler. The handler is removed and if the
1083  *      interrupt line is no longer in use by any driver it is disabled.
1084  *      On a shared IRQ the caller must ensure the interrupt is disabled
1085  *      on the card it drives before calling this function. The function
1086  *      does not return until any executing interrupts for this IRQ
1087  *      have completed.
1088  *
1089  *      This function must not be called from interrupt context.
1090  */
1091 void free_irq(unsigned int irq, void *dev_id)
1092 {
1093         struct irq_desc *desc = irq_to_desc(irq);
1094
1095         if (!desc)
1096                 return;
1097
1098 #ifdef CONFIG_SMP
1099         if (WARN_ON(desc->affinity_notify))
1100                 desc->affinity_notify = NULL;
1101 #endif
1102
1103         chip_bus_lock(desc);
1104         kfree(__free_irq(irq, dev_id));
1105         chip_bus_sync_unlock(desc);
1106 }
1107 EXPORT_SYMBOL(free_irq);
1108
1109 /**
1110  *      request_threaded_irq - allocate an interrupt line
1111  *      @irq: Interrupt line to allocate
1112  *      @handler: Function to be called when the IRQ occurs.
1113  *                Primary handler for threaded interrupts
1114  *                If NULL and thread_fn != NULL the default
1115  *                primary handler is installed
1116  *      @thread_fn: Function called from the irq handler thread
1117  *                  If NULL, no irq thread is created
1118  *      @irqflags: Interrupt type flags
1119  *      @devname: An ascii name for the claiming device
1120  *      @dev_id: A cookie passed back to the handler function
1121  *
1122  *      This call allocates interrupt resources and enables the
1123  *      interrupt line and IRQ handling. From the point this
1124  *      call is made your handler function may be invoked. Since
1125  *      your handler function must clear any interrupt the board
1126  *      raises, you must take care both to initialise your hardware
1127  *      and to set up the interrupt handler in the right order.
1128  *
1129  *      If you want to set up a threaded irq handler for your device
1130  *      then you need to supply @handler and @thread_fn. @handler ist
1131  *      still called in hard interrupt context and has to check
1132  *      whether the interrupt originates from the device. If yes it
1133  *      needs to disable the interrupt on the device and return
1134  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1135  *      @thread_fn. This split handler design is necessary to support
1136  *      shared interrupts.
1137  *
1138  *      Dev_id must be globally unique. Normally the address of the
1139  *      device data structure is used as the cookie. Since the handler
1140  *      receives this value it makes sense to use it.
1141  *
1142  *      If your interrupt is shared you must pass a non NULL dev_id
1143  *      as this is required when freeing the interrupt.
1144  *
1145  *      Flags:
1146  *
1147  *      IRQF_SHARED             Interrupt is shared
1148  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
1149  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1150  *
1151  */
1152 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1153                          irq_handler_t thread_fn, unsigned long irqflags,
1154                          const char *devname, void *dev_id)
1155 {
1156         struct irqaction *action;
1157         struct irq_desc *desc;
1158         int retval;
1159
1160         /*
1161          * Sanity-check: shared interrupts must pass in a real dev-ID,
1162          * otherwise we'll have trouble later trying to figure out
1163          * which interrupt is which (messes up the interrupt freeing
1164          * logic etc).
1165          */
1166         if ((irqflags & IRQF_SHARED) && !dev_id)
1167                 return -EINVAL;
1168
1169         desc = irq_to_desc(irq);
1170         if (!desc)
1171                 return -EINVAL;
1172
1173         if (desc->status & IRQ_NOREQUEST)
1174                 return -EINVAL;
1175
1176         if (!handler) {
1177                 if (!thread_fn)
1178                         return -EINVAL;
1179                 handler = irq_default_primary_handler;
1180         }
1181
1182         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1183         if (!action)
1184                 return -ENOMEM;
1185
1186         action->handler = handler;
1187         action->thread_fn = thread_fn;
1188         action->flags = irqflags;
1189         action->name = devname;
1190         action->dev_id = dev_id;
1191
1192         chip_bus_lock(desc);
1193         retval = __setup_irq(irq, desc, action);
1194         chip_bus_sync_unlock(desc);
1195
1196         if (retval)
1197                 kfree(action);
1198
1199 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1200         if (!retval && (irqflags & IRQF_SHARED)) {
1201                 /*
1202                  * It's a shared IRQ -- the driver ought to be prepared for it
1203                  * to happen immediately, so let's make sure....
1204                  * We disable the irq to make sure that a 'real' IRQ doesn't
1205                  * run in parallel with our fake.
1206                  */
1207                 unsigned long flags;
1208
1209                 disable_irq(irq);
1210                 local_irq_save(flags);
1211
1212                 handler(irq, dev_id);
1213
1214                 local_irq_restore(flags);
1215                 enable_irq(irq);
1216         }
1217 #endif
1218         return retval;
1219 }
1220 EXPORT_SYMBOL(request_threaded_irq);
1221
1222 /**
1223  *      request_any_context_irq - allocate an interrupt line
1224  *      @irq: Interrupt line to allocate
1225  *      @handler: Function to be called when the IRQ occurs.
1226  *                Threaded handler for threaded interrupts.
1227  *      @flags: Interrupt type flags
1228  *      @name: An ascii name for the claiming device
1229  *      @dev_id: A cookie passed back to the handler function
1230  *
1231  *      This call allocates interrupt resources and enables the
1232  *      interrupt line and IRQ handling. It selects either a
1233  *      hardirq or threaded handling method depending on the
1234  *      context.
1235  *
1236  *      On failure, it returns a negative value. On success,
1237  *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1238  */
1239 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1240                             unsigned long flags, const char *name, void *dev_id)
1241 {
1242         struct irq_desc *desc = irq_to_desc(irq);
1243         int ret;
1244
1245         if (!desc)
1246                 return -EINVAL;
1247
1248         if (desc->status & IRQ_NESTED_THREAD) {
1249                 ret = request_threaded_irq(irq, NULL, handler,
1250                                            flags, name, dev_id);
1251                 return !ret ? IRQC_IS_NESTED : ret;
1252         }
1253
1254         ret = request_irq(irq, handler, flags, name, dev_id);
1255         return !ret ? IRQC_IS_HARDIRQ : ret;
1256 }
1257 EXPORT_SYMBOL_GPL(request_any_context_irq);