genirq: Add IRQCHIP_SET_TYPE_MASKED flag
[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 state;
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->istate & IRQS_INPROGRESS)
46                         cpu_relax();
47
48                 /* Ok, that indicated we're done: double-check carefully. */
49                 raw_spin_lock_irqsave(&desc->lock, flags);
50                 state = desc->istate;
51                 raw_spin_unlock_irqrestore(&desc->lock, flags);
52
53                 /* Oops, that failed? */
54         } while (state & IRQS_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 (!desc || !irqd_can_balance(&desc->irq_data) ||
77             !desc->irq_data.chip || !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 #ifdef CONFIG_GENERIC_PENDING_IRQ
104 static inline bool irq_can_move_pcntxt(struct irq_desc *desc)
105 {
106         return irq_settings_can_move_pcntxt(desc);
107 }
108 static inline bool irq_move_pending(struct irq_desc *desc)
109 {
110         return irqd_is_setaffinity_pending(&desc->irq_data);
111 }
112 static inline void
113 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
114 {
115         cpumask_copy(desc->pending_mask, mask);
116 }
117 static inline void
118 irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
119 {
120         cpumask_copy(mask, desc->pending_mask);
121 }
122 #else
123 static inline bool irq_can_move_pcntxt(struct irq_desc *desc) { return true; }
124 static inline bool irq_move_pending(struct irq_desc *desc) { return false; }
125 static inline void
126 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
127 static inline void
128 irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
129 #endif
130
131 /**
132  *      irq_set_affinity - Set the irq affinity of a given irq
133  *      @irq:           Interrupt to set affinity
134  *      @cpumask:       cpumask
135  *
136  */
137 int irq_set_affinity(unsigned int irq, const struct cpumask *mask)
138 {
139         struct irq_desc *desc = irq_to_desc(irq);
140         struct irq_chip *chip = desc->irq_data.chip;
141         unsigned long flags;
142         int ret = 0;
143
144         if (!chip->irq_set_affinity)
145                 return -EINVAL;
146
147         raw_spin_lock_irqsave(&desc->lock, flags);
148
149         if (irq_can_move_pcntxt(desc)) {
150                 ret = chip->irq_set_affinity(&desc->irq_data, mask, false);
151                 switch (ret) {
152                 case IRQ_SET_MASK_OK:
153                         cpumask_copy(desc->irq_data.affinity, mask);
154                 case IRQ_SET_MASK_OK_NOCOPY:
155                         irq_set_thread_affinity(desc);
156                         ret = 0;
157                 }
158         } else {
159                 irqd_set_move_pending(&desc->irq_data);
160                 irq_copy_pending(desc, mask);
161         }
162
163         if (desc->affinity_notify) {
164                 kref_get(&desc->affinity_notify->kref);
165                 schedule_work(&desc->affinity_notify->work);
166         }
167         irq_compat_set_affinity(desc);
168         irqd_set(&desc->irq_data, IRQD_AFFINITY_SET);
169         raw_spin_unlock_irqrestore(&desc->lock, flags);
170         return ret;
171 }
172
173 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
174 {
175         struct irq_desc *desc = irq_to_desc(irq);
176         unsigned long flags;
177
178         if (!desc)
179                 return -EINVAL;
180
181         raw_spin_lock_irqsave(&desc->lock, flags);
182         desc->affinity_hint = m;
183         raw_spin_unlock_irqrestore(&desc->lock, flags);
184
185         return 0;
186 }
187 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
188
189 static void irq_affinity_notify(struct work_struct *work)
190 {
191         struct irq_affinity_notify *notify =
192                 container_of(work, struct irq_affinity_notify, work);
193         struct irq_desc *desc = irq_to_desc(notify->irq);
194         cpumask_var_t cpumask;
195         unsigned long flags;
196
197         if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
198                 goto out;
199
200         raw_spin_lock_irqsave(&desc->lock, flags);
201         if (irq_move_pending(desc))
202                 irq_get_pending(cpumask, desc);
203         else
204                 cpumask_copy(cpumask, desc->irq_data.affinity);
205         raw_spin_unlock_irqrestore(&desc->lock, flags);
206
207         notify->notify(notify, cpumask);
208
209         free_cpumask_var(cpumask);
210 out:
211         kref_put(&notify->kref, notify->release);
212 }
213
214 /**
215  *      irq_set_affinity_notifier - control notification of IRQ affinity changes
216  *      @irq:           Interrupt for which to enable/disable notification
217  *      @notify:        Context for notification, or %NULL to disable
218  *                      notification.  Function pointers must be initialised;
219  *                      the other fields will be initialised by this function.
220  *
221  *      Must be called in process context.  Notification may only be enabled
222  *      after the IRQ is allocated and must be disabled before the IRQ is
223  *      freed using free_irq().
224  */
225 int
226 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
227 {
228         struct irq_desc *desc = irq_to_desc(irq);
229         struct irq_affinity_notify *old_notify;
230         unsigned long flags;
231
232         /* The release function is promised process context */
233         might_sleep();
234
235         if (!desc)
236                 return -EINVAL;
237
238         /* Complete initialisation of *notify */
239         if (notify) {
240                 notify->irq = irq;
241                 kref_init(&notify->kref);
242                 INIT_WORK(&notify->work, irq_affinity_notify);
243         }
244
245         raw_spin_lock_irqsave(&desc->lock, flags);
246         old_notify = desc->affinity_notify;
247         desc->affinity_notify = notify;
248         raw_spin_unlock_irqrestore(&desc->lock, flags);
249
250         if (old_notify)
251                 kref_put(&old_notify->kref, old_notify->release);
252
253         return 0;
254 }
255 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
256
257 #ifndef CONFIG_AUTO_IRQ_AFFINITY
258 /*
259  * Generic version of the affinity autoselector.
260  */
261 static int
262 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
263 {
264         struct irq_chip *chip = irq_desc_get_chip(desc);
265         struct cpumask *set = irq_default_affinity;
266         int ret;
267
268         /* Excludes PER_CPU and NO_BALANCE interrupts */
269         if (!irq_can_set_affinity(irq))
270                 return 0;
271
272         /*
273          * Preserve an userspace affinity setup, but make sure that
274          * one of the targets is online.
275          */
276         if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
277                 if (cpumask_intersects(desc->irq_data.affinity,
278                                        cpu_online_mask))
279                         set = desc->irq_data.affinity;
280                 else {
281                         irq_compat_clr_affinity(desc);
282                         irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
283                 }
284         }
285
286         cpumask_and(mask, cpu_online_mask, set);
287         ret = chip->irq_set_affinity(&desc->irq_data, mask, false);
288         switch (ret) {
289         case IRQ_SET_MASK_OK:
290                 cpumask_copy(desc->irq_data.affinity, mask);
291         case IRQ_SET_MASK_OK_NOCOPY:
292                 irq_set_thread_affinity(desc);
293         }
294         return 0;
295 }
296 #else
297 static inline int
298 setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
299 {
300         return irq_select_affinity(irq);
301 }
302 #endif
303
304 /*
305  * Called when affinity is set via /proc/irq
306  */
307 int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
308 {
309         struct irq_desc *desc = irq_to_desc(irq);
310         unsigned long flags;
311         int ret;
312
313         raw_spin_lock_irqsave(&desc->lock, flags);
314         ret = setup_affinity(irq, desc, mask);
315         raw_spin_unlock_irqrestore(&desc->lock, flags);
316         return ret;
317 }
318
319 #else
320 static inline int
321 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
322 {
323         return 0;
324 }
325 #endif
326
327 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
328 {
329         if (suspend) {
330                 if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
331                         return;
332                 desc->istate |= IRQS_SUSPENDED;
333         }
334
335         if (!desc->depth++)
336                 irq_disable(desc);
337 }
338
339 /**
340  *      disable_irq_nosync - disable an irq without waiting
341  *      @irq: Interrupt to disable
342  *
343  *      Disable the selected interrupt line.  Disables and Enables are
344  *      nested.
345  *      Unlike disable_irq(), this function does not ensure existing
346  *      instances of the IRQ handler have completed before returning.
347  *
348  *      This function may be called from IRQ context.
349  */
350 void disable_irq_nosync(unsigned int irq)
351 {
352         struct irq_desc *desc = irq_to_desc(irq);
353         unsigned long flags;
354
355         if (!desc)
356                 return;
357
358         chip_bus_lock(desc);
359         raw_spin_lock_irqsave(&desc->lock, flags);
360         __disable_irq(desc, irq, false);
361         raw_spin_unlock_irqrestore(&desc->lock, flags);
362         chip_bus_sync_unlock(desc);
363 }
364 EXPORT_SYMBOL(disable_irq_nosync);
365
366 /**
367  *      disable_irq - disable an irq and wait for completion
368  *      @irq: Interrupt to disable
369  *
370  *      Disable the selected interrupt line.  Enables and Disables are
371  *      nested.
372  *      This function waits for any pending IRQ handlers for this interrupt
373  *      to complete before returning. If you use this function while
374  *      holding a resource the IRQ handler may need you will deadlock.
375  *
376  *      This function may be called - with care - from IRQ context.
377  */
378 void disable_irq(unsigned int irq)
379 {
380         struct irq_desc *desc = irq_to_desc(irq);
381
382         if (!desc)
383                 return;
384
385         disable_irq_nosync(irq);
386         if (desc->action)
387                 synchronize_irq(irq);
388 }
389 EXPORT_SYMBOL(disable_irq);
390
391 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
392 {
393         if (resume) {
394                 if (!(desc->istate & IRQS_SUSPENDED)) {
395                         if (!desc->action)
396                                 return;
397                         if (!(desc->action->flags & IRQF_FORCE_RESUME))
398                                 return;
399                         /* Pretend that it got disabled ! */
400                         desc->depth++;
401                 }
402                 desc->istate &= ~IRQS_SUSPENDED;
403         }
404
405         switch (desc->depth) {
406         case 0:
407  err_out:
408                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
409                 break;
410         case 1: {
411                 if (desc->istate & IRQS_SUSPENDED)
412                         goto err_out;
413                 /* Prevent probing on this irq: */
414                 irq_settings_set_noprobe(desc);
415                 irq_enable(desc);
416                 check_irq_resend(desc, irq);
417                 /* fall-through */
418         }
419         default:
420                 desc->depth--;
421         }
422 }
423
424 /**
425  *      enable_irq - enable handling of an irq
426  *      @irq: Interrupt to enable
427  *
428  *      Undoes the effect of one call to disable_irq().  If this
429  *      matches the last disable, processing of interrupts on this
430  *      IRQ line is re-enabled.
431  *
432  *      This function may be called from IRQ context only when
433  *      desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
434  */
435 void enable_irq(unsigned int irq)
436 {
437         struct irq_desc *desc = irq_to_desc(irq);
438         unsigned long flags;
439
440         if (!desc)
441                 return;
442
443         if (WARN(!desc->irq_data.chip,
444                  KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
445                 return;
446
447         chip_bus_lock(desc);
448         raw_spin_lock_irqsave(&desc->lock, flags);
449         __enable_irq(desc, irq, false);
450         raw_spin_unlock_irqrestore(&desc->lock, flags);
451         chip_bus_sync_unlock(desc);
452 }
453 EXPORT_SYMBOL(enable_irq);
454
455 static int set_irq_wake_real(unsigned int irq, unsigned int on)
456 {
457         struct irq_desc *desc = irq_to_desc(irq);
458         int ret = -ENXIO;
459
460         if (desc->irq_data.chip->irq_set_wake)
461                 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
462
463         return ret;
464 }
465
466 /**
467  *      irq_set_irq_wake - control irq power management wakeup
468  *      @irq:   interrupt to control
469  *      @on:    enable/disable power management wakeup
470  *
471  *      Enable/disable power management wakeup mode, which is
472  *      disabled by default.  Enables and disables must match,
473  *      just as they match for non-wakeup mode support.
474  *
475  *      Wakeup mode lets this IRQ wake the system from sleep
476  *      states like "suspend to RAM".
477  */
478 int irq_set_irq_wake(unsigned int irq, unsigned int on)
479 {
480         struct irq_desc *desc = irq_to_desc(irq);
481         unsigned long flags;
482         int ret = 0;
483
484         /* wakeup-capable irqs can be shared between drivers that
485          * don't need to have the same sleep mode behaviors.
486          */
487         chip_bus_lock(desc);
488         raw_spin_lock_irqsave(&desc->lock, flags);
489         if (on) {
490                 if (desc->wake_depth++ == 0) {
491                         ret = set_irq_wake_real(irq, on);
492                         if (ret)
493                                 desc->wake_depth = 0;
494                         else
495                                 desc->istate |= IRQS_WAKEUP;
496                 }
497         } else {
498                 if (desc->wake_depth == 0) {
499                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
500                 } else if (--desc->wake_depth == 0) {
501                         ret = set_irq_wake_real(irq, on);
502                         if (ret)
503                                 desc->wake_depth = 1;
504                         else
505                                 desc->istate &= ~IRQS_WAKEUP;
506                 }
507         }
508
509         raw_spin_unlock_irqrestore(&desc->lock, flags);
510         chip_bus_sync_unlock(desc);
511         return ret;
512 }
513 EXPORT_SYMBOL(irq_set_irq_wake);
514
515 /*
516  * Internal function that tells the architecture code whether a
517  * particular irq has been exclusively allocated or is available
518  * for driver use.
519  */
520 int can_request_irq(unsigned int irq, unsigned long irqflags)
521 {
522         struct irq_desc *desc = irq_to_desc(irq);
523         struct irqaction *action;
524         unsigned long flags;
525
526         if (!desc)
527                 return 0;
528
529         if (!irq_settings_can_request(desc))
530                 return 0;
531
532         raw_spin_lock_irqsave(&desc->lock, flags);
533         action = desc->action;
534         if (action)
535                 if (irqflags & action->flags & IRQF_SHARED)
536                         action = NULL;
537
538         raw_spin_unlock_irqrestore(&desc->lock, flags);
539
540         return !action;
541 }
542
543 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
544 {
545         /*
546          * If the architecture still has not overriden
547          * the flow handler then zap the default. This
548          * should catch incorrect flow-type setting.
549          */
550         if (desc->handle_irq == &handle_bad_irq)
551                 desc->handle_irq = NULL;
552 }
553
554 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
555                       unsigned long flags)
556 {
557         struct irq_chip *chip = desc->irq_data.chip;
558         int ret, unmask = 0;
559
560         if (!chip || !chip->irq_set_type) {
561                 /*
562                  * IRQF_TRIGGER_* but the PIC does not support multiple
563                  * flow-types?
564                  */
565                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
566                                 chip ? (chip->name ? : "unknown") : "unknown");
567                 return 0;
568         }
569
570         flags &= IRQ_TYPE_SENSE_MASK;
571
572         if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
573                 if (!(desc->istate & IRQS_MASKED))
574                         mask_irq(desc);
575                 if (!(desc->istate & IRQS_DISABLED))
576                         unmask = 1;
577         }
578
579         /* caller masked out all except trigger mode flags */
580         ret = chip->irq_set_type(&desc->irq_data, flags);
581
582         switch (ret) {
583         case IRQ_SET_MASK_OK:
584                 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
585                 irqd_set(&desc->irq_data, flags);
586
587         case IRQ_SET_MASK_OK_NOCOPY:
588                 flags = irqd_get_trigger_type(&desc->irq_data);
589                 irq_settings_set_trigger_mask(desc, flags);
590                 irqd_clear(&desc->irq_data, IRQD_LEVEL);
591                 irq_settings_clr_level(desc);
592                 if (flags & IRQ_TYPE_LEVEL_MASK) {
593                         irq_settings_set_level(desc);
594                         irqd_set(&desc->irq_data, IRQD_LEVEL);
595                 }
596
597                 if (chip != desc->irq_data.chip)
598                         irq_chip_set_defaults(desc->irq_data.chip);
599                 ret = 0;
600         default:
601                 pr_err("setting trigger mode %lu for irq %u failed (%pF)\n",
602                        flags, irq, chip->irq_set_type);
603         }
604         if (unmask)
605                 unmask_irq(desc);
606         return ret;
607 }
608
609 /*
610  * Default primary interrupt handler for threaded interrupts. Is
611  * assigned as primary handler when request_threaded_irq is called
612  * with handler == NULL. Useful for oneshot interrupts.
613  */
614 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
615 {
616         return IRQ_WAKE_THREAD;
617 }
618
619 /*
620  * Primary handler for nested threaded interrupts. Should never be
621  * called.
622  */
623 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
624 {
625         WARN(1, "Primary handler called for nested irq %d\n", irq);
626         return IRQ_NONE;
627 }
628
629 static int irq_wait_for_interrupt(struct irqaction *action)
630 {
631         while (!kthread_should_stop()) {
632                 set_current_state(TASK_INTERRUPTIBLE);
633
634                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
635                                        &action->thread_flags)) {
636                         __set_current_state(TASK_RUNNING);
637                         return 0;
638                 }
639                 schedule();
640         }
641         return -1;
642 }
643
644 /*
645  * Oneshot interrupts keep the irq line masked until the threaded
646  * handler finished. unmask if the interrupt has not been disabled and
647  * is marked MASKED.
648  */
649 static void irq_finalize_oneshot(unsigned int irq, struct irq_desc *desc)
650 {
651 again:
652         chip_bus_lock(desc);
653         raw_spin_lock_irq(&desc->lock);
654
655         /*
656          * Implausible though it may be we need to protect us against
657          * the following scenario:
658          *
659          * The thread is faster done than the hard interrupt handler
660          * on the other CPU. If we unmask the irq line then the
661          * interrupt can come in again and masks the line, leaves due
662          * to IRQS_INPROGRESS and the irq line is masked forever.
663          */
664         if (unlikely(desc->istate & IRQS_INPROGRESS)) {
665                 raw_spin_unlock_irq(&desc->lock);
666                 chip_bus_sync_unlock(desc);
667                 cpu_relax();
668                 goto again;
669         }
670
671         if (!(desc->istate & IRQS_DISABLED) && (desc->istate & IRQS_MASKED)) {
672                 irq_compat_clr_masked(desc);
673                 desc->istate &= ~IRQS_MASKED;
674                 desc->irq_data.chip->irq_unmask(&desc->irq_data);
675         }
676         raw_spin_unlock_irq(&desc->lock);
677         chip_bus_sync_unlock(desc);
678 }
679
680 #ifdef CONFIG_SMP
681 /*
682  * Check whether we need to chasnge the affinity of the interrupt thread.
683  */
684 static void
685 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
686 {
687         cpumask_var_t mask;
688
689         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
690                 return;
691
692         /*
693          * In case we are out of memory we set IRQTF_AFFINITY again and
694          * try again next time
695          */
696         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
697                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
698                 return;
699         }
700
701         raw_spin_lock_irq(&desc->lock);
702         cpumask_copy(mask, desc->irq_data.affinity);
703         raw_spin_unlock_irq(&desc->lock);
704
705         set_cpus_allowed_ptr(current, mask);
706         free_cpumask_var(mask);
707 }
708 #else
709 static inline void
710 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
711 #endif
712
713 /*
714  * Interrupt handler thread
715  */
716 static int irq_thread(void *data)
717 {
718         static const struct sched_param param = {
719                 .sched_priority = MAX_USER_RT_PRIO/2,
720         };
721         struct irqaction *action = data;
722         struct irq_desc *desc = irq_to_desc(action->irq);
723         int wake, oneshot = desc->istate & IRQS_ONESHOT;
724
725         sched_setscheduler(current, SCHED_FIFO, &param);
726         current->irqaction = action;
727
728         while (!irq_wait_for_interrupt(action)) {
729
730                 irq_thread_check_affinity(desc, action);
731
732                 atomic_inc(&desc->threads_active);
733
734                 raw_spin_lock_irq(&desc->lock);
735                 if (unlikely(desc->istate & IRQS_DISABLED)) {
736                         /*
737                          * CHECKME: We might need a dedicated
738                          * IRQ_THREAD_PENDING flag here, which
739                          * retriggers the thread in check_irq_resend()
740                          * but AFAICT IRQS_PENDING should be fine as it
741                          * retriggers the interrupt itself --- tglx
742                          */
743                         irq_compat_set_pending(desc);
744                         desc->istate |= IRQS_PENDING;
745                         raw_spin_unlock_irq(&desc->lock);
746                 } else {
747                         raw_spin_unlock_irq(&desc->lock);
748
749                         action->thread_fn(action->irq, action->dev_id);
750
751                         if (oneshot)
752                                 irq_finalize_oneshot(action->irq, desc);
753                 }
754
755                 wake = atomic_dec_and_test(&desc->threads_active);
756
757                 if (wake && waitqueue_active(&desc->wait_for_threads))
758                         wake_up(&desc->wait_for_threads);
759         }
760
761         /*
762          * Clear irqaction. Otherwise exit_irq_thread() would make
763          * fuzz about an active irq thread going into nirvana.
764          */
765         current->irqaction = NULL;
766         return 0;
767 }
768
769 /*
770  * Called from do_exit()
771  */
772 void exit_irq_thread(void)
773 {
774         struct task_struct *tsk = current;
775
776         if (!tsk->irqaction)
777                 return;
778
779         printk(KERN_ERR
780                "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
781                tsk->comm ? tsk->comm : "", tsk->pid, tsk->irqaction->irq);
782
783         /*
784          * Set the THREAD DIED flag to prevent further wakeups of the
785          * soon to be gone threaded handler.
786          */
787         set_bit(IRQTF_DIED, &tsk->irqaction->flags);
788 }
789
790 /*
791  * Internal function to register an irqaction - typically used to
792  * allocate special interrupts that are part of the architecture.
793  */
794 static int
795 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
796 {
797         struct irqaction *old, **old_ptr;
798         const char *old_name = NULL;
799         unsigned long flags;
800         int ret, nested, shared = 0;
801         cpumask_var_t mask;
802
803         if (!desc)
804                 return -EINVAL;
805
806         if (desc->irq_data.chip == &no_irq_chip)
807                 return -ENOSYS;
808         /*
809          * Some drivers like serial.c use request_irq() heavily,
810          * so we have to be careful not to interfere with a
811          * running system.
812          */
813         if (new->flags & IRQF_SAMPLE_RANDOM) {
814                 /*
815                  * This function might sleep, we want to call it first,
816                  * outside of the atomic block.
817                  * Yes, this might clear the entropy pool if the wrong
818                  * driver is attempted to be loaded, without actually
819                  * installing a new handler, but is this really a problem,
820                  * only the sysadmin is able to do this.
821                  */
822                 rand_initialize_irq(irq);
823         }
824
825         /* Oneshot interrupts are not allowed with shared */
826         if ((new->flags & IRQF_ONESHOT) && (new->flags & IRQF_SHARED))
827                 return -EINVAL;
828
829         /*
830          * Check whether the interrupt nests into another interrupt
831          * thread.
832          */
833         nested = irq_settings_is_nested_thread(desc);
834         if (nested) {
835                 if (!new->thread_fn)
836                         return -EINVAL;
837                 /*
838                  * Replace the primary handler which was provided from
839                  * the driver for non nested interrupt handling by the
840                  * dummy function which warns when called.
841                  */
842                 new->handler = irq_nested_primary_handler;
843         }
844
845         /*
846          * Create a handler thread when a thread function is supplied
847          * and the interrupt does not nest into another interrupt
848          * thread.
849          */
850         if (new->thread_fn && !nested) {
851                 struct task_struct *t;
852
853                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
854                                    new->name);
855                 if (IS_ERR(t))
856                         return PTR_ERR(t);
857                 /*
858                  * We keep the reference to the task struct even if
859                  * the thread dies to avoid that the interrupt code
860                  * references an already freed task_struct.
861                  */
862                 get_task_struct(t);
863                 new->thread = t;
864         }
865
866         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
867                 ret = -ENOMEM;
868                 goto out_thread;
869         }
870
871         /*
872          * The following block of code has to be executed atomically
873          */
874         raw_spin_lock_irqsave(&desc->lock, flags);
875         old_ptr = &desc->action;
876         old = *old_ptr;
877         if (old) {
878                 /*
879                  * Can't share interrupts unless both agree to and are
880                  * the same type (level, edge, polarity). So both flag
881                  * fields must have IRQF_SHARED set and the bits which
882                  * set the trigger type must match.
883                  */
884                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
885                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
886                         old_name = old->name;
887                         goto mismatch;
888                 }
889
890                 /* All handlers must agree on per-cpuness */
891                 if ((old->flags & IRQF_PERCPU) !=
892                     (new->flags & IRQF_PERCPU))
893                         goto mismatch;
894
895                 /* add new interrupt at end of irq queue */
896                 do {
897                         old_ptr = &old->next;
898                         old = *old_ptr;
899                 } while (old);
900                 shared = 1;
901         }
902
903         if (!shared) {
904                 irq_chip_set_defaults(desc->irq_data.chip);
905
906                 init_waitqueue_head(&desc->wait_for_threads);
907
908                 /* Setup the type (level, edge polarity) if configured: */
909                 if (new->flags & IRQF_TRIGGER_MASK) {
910                         ret = __irq_set_trigger(desc, irq,
911                                         new->flags & IRQF_TRIGGER_MASK);
912
913                         if (ret)
914                                 goto out_mask;
915                 } else
916                         compat_irq_chip_set_default_handler(desc);
917
918                 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
919                                   IRQS_INPROGRESS | IRQS_ONESHOT | \
920                                   IRQS_WAITING);
921
922                 if (new->flags & IRQF_PERCPU) {
923                         irqd_set(&desc->irq_data, IRQD_PER_CPU);
924                         irq_settings_set_per_cpu(desc);
925                 }
926
927                 if (new->flags & IRQF_ONESHOT)
928                         desc->istate |= IRQS_ONESHOT;
929
930                 if (irq_settings_can_autoenable(desc))
931                         irq_startup(desc);
932                 else
933                         /* Undo nested disables: */
934                         desc->depth = 1;
935
936                 /* Exclude IRQ from balancing if requested */
937                 if (new->flags & IRQF_NOBALANCING) {
938                         irq_settings_set_no_balancing(desc);
939                         irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
940                 }
941
942                 /* Set default affinity mask once everything is setup */
943                 setup_affinity(irq, desc, mask);
944
945         } else if (new->flags & IRQF_TRIGGER_MASK) {
946                 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
947                 unsigned int omsk = irq_settings_get_trigger_mask(desc);
948
949                 if (nmsk != omsk)
950                         /* hope the handler works with current  trigger mode */
951                         pr_warning("IRQ %d uses trigger mode %u; requested %u\n",
952                                    irq, nmsk, omsk);
953         }
954
955         new->irq = irq;
956         *old_ptr = new;
957
958         /* Reset broken irq detection when installing new handler */
959         desc->irq_count = 0;
960         desc->irqs_unhandled = 0;
961
962         /*
963          * Check whether we disabled the irq via the spurious handler
964          * before. Reenable it and give it another chance.
965          */
966         if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
967                 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
968                 __enable_irq(desc, irq, false);
969         }
970
971         raw_spin_unlock_irqrestore(&desc->lock, flags);
972
973         /*
974          * Strictly no need to wake it up, but hung_task complains
975          * when no hard interrupt wakes the thread up.
976          */
977         if (new->thread)
978                 wake_up_process(new->thread);
979
980         register_irq_proc(irq, desc);
981         new->dir = NULL;
982         register_handler_proc(irq, new);
983
984         return 0;
985
986 mismatch:
987 #ifdef CONFIG_DEBUG_SHIRQ
988         if (!(new->flags & IRQF_PROBE_SHARED)) {
989                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
990                 if (old_name)
991                         printk(KERN_ERR "current handler: %s\n", old_name);
992                 dump_stack();
993         }
994 #endif
995         ret = -EBUSY;
996
997 out_mask:
998         free_cpumask_var(mask);
999
1000 out_thread:
1001         raw_spin_unlock_irqrestore(&desc->lock, flags);
1002         if (new->thread) {
1003                 struct task_struct *t = new->thread;
1004
1005                 new->thread = NULL;
1006                 if (likely(!test_bit(IRQTF_DIED, &new->thread_flags)))
1007                         kthread_stop(t);
1008                 put_task_struct(t);
1009         }
1010         return ret;
1011 }
1012
1013 /**
1014  *      setup_irq - setup an interrupt
1015  *      @irq: Interrupt line to setup
1016  *      @act: irqaction for the interrupt
1017  *
1018  * Used to statically setup interrupts in the early boot process.
1019  */
1020 int setup_irq(unsigned int irq, struct irqaction *act)
1021 {
1022         int retval;
1023         struct irq_desc *desc = irq_to_desc(irq);
1024
1025         chip_bus_lock(desc);
1026         retval = __setup_irq(irq, desc, act);
1027         chip_bus_sync_unlock(desc);
1028
1029         return retval;
1030 }
1031 EXPORT_SYMBOL_GPL(setup_irq);
1032
1033  /*
1034  * Internal function to unregister an irqaction - used to free
1035  * regular and special interrupts that are part of the architecture.
1036  */
1037 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1038 {
1039         struct irq_desc *desc = irq_to_desc(irq);
1040         struct irqaction *action, **action_ptr;
1041         unsigned long flags;
1042
1043         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1044
1045         if (!desc)
1046                 return NULL;
1047
1048         raw_spin_lock_irqsave(&desc->lock, flags);
1049
1050         /*
1051          * There can be multiple actions per IRQ descriptor, find the right
1052          * one based on the dev_id:
1053          */
1054         action_ptr = &desc->action;
1055         for (;;) {
1056                 action = *action_ptr;
1057
1058                 if (!action) {
1059                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
1060                         raw_spin_unlock_irqrestore(&desc->lock, flags);
1061
1062                         return NULL;
1063                 }
1064
1065                 if (action->dev_id == dev_id)
1066                         break;
1067                 action_ptr = &action->next;
1068         }
1069
1070         /* Found it - now remove it from the list of entries: */
1071         *action_ptr = action->next;
1072
1073         /* Currently used only by UML, might disappear one day: */
1074 #ifdef CONFIG_IRQ_RELEASE_METHOD
1075         if (desc->irq_data.chip->release)
1076                 desc->irq_data.chip->release(irq, dev_id);
1077 #endif
1078
1079         /* If this was the last handler, shut down the IRQ line: */
1080         if (!desc->action)
1081                 irq_shutdown(desc);
1082
1083 #ifdef CONFIG_SMP
1084         /* make sure affinity_hint is cleaned up */
1085         if (WARN_ON_ONCE(desc->affinity_hint))
1086                 desc->affinity_hint = NULL;
1087 #endif
1088
1089         raw_spin_unlock_irqrestore(&desc->lock, flags);
1090
1091         unregister_handler_proc(irq, action);
1092
1093         /* Make sure it's not being used on another CPU: */
1094         synchronize_irq(irq);
1095
1096 #ifdef CONFIG_DEBUG_SHIRQ
1097         /*
1098          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1099          * event to happen even now it's being freed, so let's make sure that
1100          * is so by doing an extra call to the handler ....
1101          *
1102          * ( We do this after actually deregistering it, to make sure that a
1103          *   'real' IRQ doesn't run in * parallel with our fake. )
1104          */
1105         if (action->flags & IRQF_SHARED) {
1106                 local_irq_save(flags);
1107                 action->handler(irq, dev_id);
1108                 local_irq_restore(flags);
1109         }
1110 #endif
1111
1112         if (action->thread) {
1113                 if (!test_bit(IRQTF_DIED, &action->thread_flags))
1114                         kthread_stop(action->thread);
1115                 put_task_struct(action->thread);
1116         }
1117
1118         return action;
1119 }
1120
1121 /**
1122  *      remove_irq - free an interrupt
1123  *      @irq: Interrupt line to free
1124  *      @act: irqaction for the interrupt
1125  *
1126  * Used to remove interrupts statically setup by the early boot process.
1127  */
1128 void remove_irq(unsigned int irq, struct irqaction *act)
1129 {
1130         __free_irq(irq, act->dev_id);
1131 }
1132 EXPORT_SYMBOL_GPL(remove_irq);
1133
1134 /**
1135  *      free_irq - free an interrupt allocated with request_irq
1136  *      @irq: Interrupt line to free
1137  *      @dev_id: Device identity to free
1138  *
1139  *      Remove an interrupt handler. The handler is removed and if the
1140  *      interrupt line is no longer in use by any driver it is disabled.
1141  *      On a shared IRQ the caller must ensure the interrupt is disabled
1142  *      on the card it drives before calling this function. The function
1143  *      does not return until any executing interrupts for this IRQ
1144  *      have completed.
1145  *
1146  *      This function must not be called from interrupt context.
1147  */
1148 void free_irq(unsigned int irq, void *dev_id)
1149 {
1150         struct irq_desc *desc = irq_to_desc(irq);
1151
1152         if (!desc)
1153                 return;
1154
1155 #ifdef CONFIG_SMP
1156         if (WARN_ON(desc->affinity_notify))
1157                 desc->affinity_notify = NULL;
1158 #endif
1159
1160         chip_bus_lock(desc);
1161         kfree(__free_irq(irq, dev_id));
1162         chip_bus_sync_unlock(desc);
1163 }
1164 EXPORT_SYMBOL(free_irq);
1165
1166 /**
1167  *      request_threaded_irq - allocate an interrupt line
1168  *      @irq: Interrupt line to allocate
1169  *      @handler: Function to be called when the IRQ occurs.
1170  *                Primary handler for threaded interrupts
1171  *                If NULL and thread_fn != NULL the default
1172  *                primary handler is installed
1173  *      @thread_fn: Function called from the irq handler thread
1174  *                  If NULL, no irq thread is created
1175  *      @irqflags: Interrupt type flags
1176  *      @devname: An ascii name for the claiming device
1177  *      @dev_id: A cookie passed back to the handler function
1178  *
1179  *      This call allocates interrupt resources and enables the
1180  *      interrupt line and IRQ handling. From the point this
1181  *      call is made your handler function may be invoked. Since
1182  *      your handler function must clear any interrupt the board
1183  *      raises, you must take care both to initialise your hardware
1184  *      and to set up the interrupt handler in the right order.
1185  *
1186  *      If you want to set up a threaded irq handler for your device
1187  *      then you need to supply @handler and @thread_fn. @handler ist
1188  *      still called in hard interrupt context and has to check
1189  *      whether the interrupt originates from the device. If yes it
1190  *      needs to disable the interrupt on the device and return
1191  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1192  *      @thread_fn. This split handler design is necessary to support
1193  *      shared interrupts.
1194  *
1195  *      Dev_id must be globally unique. Normally the address of the
1196  *      device data structure is used as the cookie. Since the handler
1197  *      receives this value it makes sense to use it.
1198  *
1199  *      If your interrupt is shared you must pass a non NULL dev_id
1200  *      as this is required when freeing the interrupt.
1201  *
1202  *      Flags:
1203  *
1204  *      IRQF_SHARED             Interrupt is shared
1205  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
1206  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1207  *
1208  */
1209 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1210                          irq_handler_t thread_fn, unsigned long irqflags,
1211                          const char *devname, void *dev_id)
1212 {
1213         struct irqaction *action;
1214         struct irq_desc *desc;
1215         int retval;
1216
1217         /*
1218          * Sanity-check: shared interrupts must pass in a real dev-ID,
1219          * otherwise we'll have trouble later trying to figure out
1220          * which interrupt is which (messes up the interrupt freeing
1221          * logic etc).
1222          */
1223         if ((irqflags & IRQF_SHARED) && !dev_id)
1224                 return -EINVAL;
1225
1226         desc = irq_to_desc(irq);
1227         if (!desc)
1228                 return -EINVAL;
1229
1230         if (!irq_settings_can_request(desc))
1231                 return -EINVAL;
1232
1233         if (!handler) {
1234                 if (!thread_fn)
1235                         return -EINVAL;
1236                 handler = irq_default_primary_handler;
1237         }
1238
1239         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1240         if (!action)
1241                 return -ENOMEM;
1242
1243         action->handler = handler;
1244         action->thread_fn = thread_fn;
1245         action->flags = irqflags;
1246         action->name = devname;
1247         action->dev_id = dev_id;
1248
1249         chip_bus_lock(desc);
1250         retval = __setup_irq(irq, desc, action);
1251         chip_bus_sync_unlock(desc);
1252
1253         if (retval)
1254                 kfree(action);
1255
1256 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1257         if (!retval && (irqflags & IRQF_SHARED)) {
1258                 /*
1259                  * It's a shared IRQ -- the driver ought to be prepared for it
1260                  * to happen immediately, so let's make sure....
1261                  * We disable the irq to make sure that a 'real' IRQ doesn't
1262                  * run in parallel with our fake.
1263                  */
1264                 unsigned long flags;
1265
1266                 disable_irq(irq);
1267                 local_irq_save(flags);
1268
1269                 handler(irq, dev_id);
1270
1271                 local_irq_restore(flags);
1272                 enable_irq(irq);
1273         }
1274 #endif
1275         return retval;
1276 }
1277 EXPORT_SYMBOL(request_threaded_irq);
1278
1279 /**
1280  *      request_any_context_irq - allocate an interrupt line
1281  *      @irq: Interrupt line to allocate
1282  *      @handler: Function to be called when the IRQ occurs.
1283  *                Threaded handler for threaded interrupts.
1284  *      @flags: Interrupt type flags
1285  *      @name: An ascii name for the claiming device
1286  *      @dev_id: A cookie passed back to the handler function
1287  *
1288  *      This call allocates interrupt resources and enables the
1289  *      interrupt line and IRQ handling. It selects either a
1290  *      hardirq or threaded handling method depending on the
1291  *      context.
1292  *
1293  *      On failure, it returns a negative value. On success,
1294  *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1295  */
1296 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1297                             unsigned long flags, const char *name, void *dev_id)
1298 {
1299         struct irq_desc *desc = irq_to_desc(irq);
1300         int ret;
1301
1302         if (!desc)
1303                 return -EINVAL;
1304
1305         if (irq_settings_is_nested_thread(desc)) {
1306                 ret = request_threaded_irq(irq, NULL, handler,
1307                                            flags, name, dev_id);
1308                 return !ret ? IRQC_IS_NESTED : ret;
1309         }
1310
1311         ret = request_irq(irq, handler, flags, name, dev_id);
1312         return !ret ? IRQC_IS_HARDIRQ : ret;
1313 }
1314 EXPORT_SYMBOL_GPL(request_any_context_irq);