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