sched: Constify function scope static struct sched_param usage
[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         if (WARN(!desc->irq_data.chip || !desc->irq_data.chip->irq_enable,
328             KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
329                 return;
330
331         chip_bus_lock(desc);
332         raw_spin_lock_irqsave(&desc->lock, flags);
333         __enable_irq(desc, irq, false);
334         raw_spin_unlock_irqrestore(&desc->lock, flags);
335         chip_bus_sync_unlock(desc);
336 }
337 EXPORT_SYMBOL(enable_irq);
338
339 static int set_irq_wake_real(unsigned int irq, unsigned int on)
340 {
341         struct irq_desc *desc = irq_to_desc(irq);
342         int ret = -ENXIO;
343
344         if (desc->irq_data.chip->irq_set_wake)
345                 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
346
347         return ret;
348 }
349
350 /**
351  *      set_irq_wake - control irq power management wakeup
352  *      @irq:   interrupt to control
353  *      @on:    enable/disable power management wakeup
354  *
355  *      Enable/disable power management wakeup mode, which is
356  *      disabled by default.  Enables and disables must match,
357  *      just as they match for non-wakeup mode support.
358  *
359  *      Wakeup mode lets this IRQ wake the system from sleep
360  *      states like "suspend to RAM".
361  */
362 int set_irq_wake(unsigned int irq, unsigned int on)
363 {
364         struct irq_desc *desc = irq_to_desc(irq);
365         unsigned long flags;
366         int ret = 0;
367
368         /* wakeup-capable irqs can be shared between drivers that
369          * don't need to have the same sleep mode behaviors.
370          */
371         raw_spin_lock_irqsave(&desc->lock, flags);
372         if (on) {
373                 if (desc->wake_depth++ == 0) {
374                         ret = set_irq_wake_real(irq, on);
375                         if (ret)
376                                 desc->wake_depth = 0;
377                         else
378                                 desc->status |= IRQ_WAKEUP;
379                 }
380         } else {
381                 if (desc->wake_depth == 0) {
382                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
383                 } else if (--desc->wake_depth == 0) {
384                         ret = set_irq_wake_real(irq, on);
385                         if (ret)
386                                 desc->wake_depth = 1;
387                         else
388                                 desc->status &= ~IRQ_WAKEUP;
389                 }
390         }
391
392         raw_spin_unlock_irqrestore(&desc->lock, flags);
393         return ret;
394 }
395 EXPORT_SYMBOL(set_irq_wake);
396
397 /*
398  * Internal function that tells the architecture code whether a
399  * particular irq has been exclusively allocated or is available
400  * for driver use.
401  */
402 int can_request_irq(unsigned int irq, unsigned long irqflags)
403 {
404         struct irq_desc *desc = irq_to_desc(irq);
405         struct irqaction *action;
406         unsigned long flags;
407
408         if (!desc)
409                 return 0;
410
411         if (desc->status & IRQ_NOREQUEST)
412                 return 0;
413
414         raw_spin_lock_irqsave(&desc->lock, flags);
415         action = desc->action;
416         if (action)
417                 if (irqflags & action->flags & IRQF_SHARED)
418                         action = NULL;
419
420         raw_spin_unlock_irqrestore(&desc->lock, flags);
421
422         return !action;
423 }
424
425 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
426 {
427         /*
428          * If the architecture still has not overriden
429          * the flow handler then zap the default. This
430          * should catch incorrect flow-type setting.
431          */
432         if (desc->handle_irq == &handle_bad_irq)
433                 desc->handle_irq = NULL;
434 }
435
436 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
437                       unsigned long flags)
438 {
439         int ret;
440         struct irq_chip *chip = desc->irq_data.chip;
441
442         if (!chip || !chip->irq_set_type) {
443                 /*
444                  * IRQF_TRIGGER_* but the PIC does not support multiple
445                  * flow-types?
446                  */
447                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
448                                 chip ? (chip->name ? : "unknown") : "unknown");
449                 return 0;
450         }
451
452         /* caller masked out all except trigger mode flags */
453         ret = chip->irq_set_type(&desc->irq_data, flags);
454
455         if (ret)
456                 pr_err("setting trigger mode %lu for irq %u failed (%pF)\n",
457                        flags, irq, chip->irq_set_type);
458         else {
459                 if (flags & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
460                         flags |= IRQ_LEVEL;
461                 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
462                 desc->status &= ~(IRQ_LEVEL | IRQ_TYPE_SENSE_MASK);
463                 desc->status |= flags;
464
465                 if (chip != desc->irq_data.chip)
466                         irq_chip_set_defaults(desc->irq_data.chip);
467         }
468
469         return ret;
470 }
471
472 /*
473  * Default primary interrupt handler for threaded interrupts. Is
474  * assigned as primary handler when request_threaded_irq is called
475  * with handler == NULL. Useful for oneshot interrupts.
476  */
477 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
478 {
479         return IRQ_WAKE_THREAD;
480 }
481
482 /*
483  * Primary handler for nested threaded interrupts. Should never be
484  * called.
485  */
486 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
487 {
488         WARN(1, "Primary handler called for nested irq %d\n", irq);
489         return IRQ_NONE;
490 }
491
492 static int irq_wait_for_interrupt(struct irqaction *action)
493 {
494         while (!kthread_should_stop()) {
495                 set_current_state(TASK_INTERRUPTIBLE);
496
497                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
498                                        &action->thread_flags)) {
499                         __set_current_state(TASK_RUNNING);
500                         return 0;
501                 }
502                 schedule();
503         }
504         return -1;
505 }
506
507 /*
508  * Oneshot interrupts keep the irq line masked until the threaded
509  * handler finished. unmask if the interrupt has not been disabled and
510  * is marked MASKED.
511  */
512 static void irq_finalize_oneshot(unsigned int irq, struct irq_desc *desc)
513 {
514 again:
515         chip_bus_lock(desc);
516         raw_spin_lock_irq(&desc->lock);
517
518         /*
519          * Implausible though it may be we need to protect us against
520          * the following scenario:
521          *
522          * The thread is faster done than the hard interrupt handler
523          * on the other CPU. If we unmask the irq line then the
524          * interrupt can come in again and masks the line, leaves due
525          * to IRQ_INPROGRESS and the irq line is masked forever.
526          */
527         if (unlikely(desc->status & IRQ_INPROGRESS)) {
528                 raw_spin_unlock_irq(&desc->lock);
529                 chip_bus_sync_unlock(desc);
530                 cpu_relax();
531                 goto again;
532         }
533
534         if (!(desc->status & IRQ_DISABLED) && (desc->status & IRQ_MASKED)) {
535                 desc->status &= ~IRQ_MASKED;
536                 desc->irq_data.chip->irq_unmask(&desc->irq_data);
537         }
538         raw_spin_unlock_irq(&desc->lock);
539         chip_bus_sync_unlock(desc);
540 }
541
542 #ifdef CONFIG_SMP
543 /*
544  * Check whether we need to change the affinity of the interrupt thread.
545  */
546 static void
547 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
548 {
549         cpumask_var_t mask;
550
551         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
552                 return;
553
554         /*
555          * In case we are out of memory we set IRQTF_AFFINITY again and
556          * try again next time
557          */
558         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
559                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
560                 return;
561         }
562
563         raw_spin_lock_irq(&desc->lock);
564         cpumask_copy(mask, desc->irq_data.affinity);
565         raw_spin_unlock_irq(&desc->lock);
566
567         set_cpus_allowed_ptr(current, mask);
568         free_cpumask_var(mask);
569 }
570 #else
571 static inline void
572 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
573 #endif
574
575 /*
576  * Interrupt handler thread
577  */
578 static int irq_thread(void *data)
579 {
580         static const struct sched_param param = {
581                 .sched_priority = MAX_USER_RT_PRIO/2,
582         };
583         struct irqaction *action = data;
584         struct irq_desc *desc = irq_to_desc(action->irq);
585         int wake, oneshot = desc->status & IRQ_ONESHOT;
586
587         sched_setscheduler(current, SCHED_FIFO, &param);
588         current->irqaction = action;
589
590         while (!irq_wait_for_interrupt(action)) {
591
592                 irq_thread_check_affinity(desc, action);
593
594                 atomic_inc(&desc->threads_active);
595
596                 raw_spin_lock_irq(&desc->lock);
597                 if (unlikely(desc->status & IRQ_DISABLED)) {
598                         /*
599                          * CHECKME: We might need a dedicated
600                          * IRQ_THREAD_PENDING flag here, which
601                          * retriggers the thread in check_irq_resend()
602                          * but AFAICT IRQ_PENDING should be fine as it
603                          * retriggers the interrupt itself --- tglx
604                          */
605                         desc->status |= IRQ_PENDING;
606                         raw_spin_unlock_irq(&desc->lock);
607                 } else {
608                         raw_spin_unlock_irq(&desc->lock);
609
610                         action->thread_fn(action->irq, action->dev_id);
611
612                         if (oneshot)
613                                 irq_finalize_oneshot(action->irq, desc);
614                 }
615
616                 wake = atomic_dec_and_test(&desc->threads_active);
617
618                 if (wake && waitqueue_active(&desc->wait_for_threads))
619                         wake_up(&desc->wait_for_threads);
620         }
621
622         /*
623          * Clear irqaction. Otherwise exit_irq_thread() would make
624          * fuzz about an active irq thread going into nirvana.
625          */
626         current->irqaction = NULL;
627         return 0;
628 }
629
630 /*
631  * Called from do_exit()
632  */
633 void exit_irq_thread(void)
634 {
635         struct task_struct *tsk = current;
636
637         if (!tsk->irqaction)
638                 return;
639
640         printk(KERN_ERR
641                "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
642                tsk->comm ? tsk->comm : "", tsk->pid, tsk->irqaction->irq);
643
644         /*
645          * Set the THREAD DIED flag to prevent further wakeups of the
646          * soon to be gone threaded handler.
647          */
648         set_bit(IRQTF_DIED, &tsk->irqaction->flags);
649 }
650
651 /*
652  * Internal function to register an irqaction - typically used to
653  * allocate special interrupts that are part of the architecture.
654  */
655 static int
656 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
657 {
658         struct irqaction *old, **old_ptr;
659         const char *old_name = NULL;
660         unsigned long flags;
661         int nested, shared = 0;
662         int ret;
663
664         if (!desc)
665                 return -EINVAL;
666
667         if (desc->irq_data.chip == &no_irq_chip)
668                 return -ENOSYS;
669         /*
670          * Some drivers like serial.c use request_irq() heavily,
671          * so we have to be careful not to interfere with a
672          * running system.
673          */
674         if (new->flags & IRQF_SAMPLE_RANDOM) {
675                 /*
676                  * This function might sleep, we want to call it first,
677                  * outside of the atomic block.
678                  * Yes, this might clear the entropy pool if the wrong
679                  * driver is attempted to be loaded, without actually
680                  * installing a new handler, but is this really a problem,
681                  * only the sysadmin is able to do this.
682                  */
683                 rand_initialize_irq(irq);
684         }
685
686         /* Oneshot interrupts are not allowed with shared */
687         if ((new->flags & IRQF_ONESHOT) && (new->flags & IRQF_SHARED))
688                 return -EINVAL;
689
690         /*
691          * Check whether the interrupt nests into another interrupt
692          * thread.
693          */
694         nested = desc->status & IRQ_NESTED_THREAD;
695         if (nested) {
696                 if (!new->thread_fn)
697                         return -EINVAL;
698                 /*
699                  * Replace the primary handler which was provided from
700                  * the driver for non nested interrupt handling by the
701                  * dummy function which warns when called.
702                  */
703                 new->handler = irq_nested_primary_handler;
704         }
705
706         /*
707          * Create a handler thread when a thread function is supplied
708          * and the interrupt does not nest into another interrupt
709          * thread.
710          */
711         if (new->thread_fn && !nested) {
712                 struct task_struct *t;
713
714                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
715                                    new->name);
716                 if (IS_ERR(t))
717                         return PTR_ERR(t);
718                 /*
719                  * We keep the reference to the task struct even if
720                  * the thread dies to avoid that the interrupt code
721                  * references an already freed task_struct.
722                  */
723                 get_task_struct(t);
724                 new->thread = t;
725         }
726
727         /*
728          * The following block of code has to be executed atomically
729          */
730         raw_spin_lock_irqsave(&desc->lock, flags);
731         old_ptr = &desc->action;
732         old = *old_ptr;
733         if (old) {
734                 /*
735                  * Can't share interrupts unless both agree to and are
736                  * the same type (level, edge, polarity). So both flag
737                  * fields must have IRQF_SHARED set and the bits which
738                  * set the trigger type must match.
739                  */
740                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
741                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
742                         old_name = old->name;
743                         goto mismatch;
744                 }
745
746 #if defined(CONFIG_IRQ_PER_CPU)
747                 /* All handlers must agree on per-cpuness */
748                 if ((old->flags & IRQF_PERCPU) !=
749                     (new->flags & IRQF_PERCPU))
750                         goto mismatch;
751 #endif
752
753                 /* add new interrupt at end of irq queue */
754                 do {
755                         old_ptr = &old->next;
756                         old = *old_ptr;
757                 } while (old);
758                 shared = 1;
759         }
760
761         if (!shared) {
762                 irq_chip_set_defaults(desc->irq_data.chip);
763
764                 init_waitqueue_head(&desc->wait_for_threads);
765
766                 /* Setup the type (level, edge polarity) if configured: */
767                 if (new->flags & IRQF_TRIGGER_MASK) {
768                         ret = __irq_set_trigger(desc, irq,
769                                         new->flags & IRQF_TRIGGER_MASK);
770
771                         if (ret)
772                                 goto out_thread;
773                 } else
774                         compat_irq_chip_set_default_handler(desc);
775 #if defined(CONFIG_IRQ_PER_CPU)
776                 if (new->flags & IRQF_PERCPU)
777                         desc->status |= IRQ_PER_CPU;
778 #endif
779
780                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING | IRQ_ONESHOT |
781                                   IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
782
783                 if (new->flags & IRQF_ONESHOT)
784                         desc->status |= IRQ_ONESHOT;
785
786                 if (!(desc->status & IRQ_NOAUTOEN)) {
787                         desc->depth = 0;
788                         desc->status &= ~IRQ_DISABLED;
789                         desc->irq_data.chip->irq_startup(&desc->irq_data);
790                 } else
791                         /* Undo nested disables: */
792                         desc->depth = 1;
793
794                 /* Exclude IRQ from balancing if requested */
795                 if (new->flags & IRQF_NOBALANCING)
796                         desc->status |= IRQ_NO_BALANCING;
797
798                 /* Set default affinity mask once everything is setup */
799                 setup_affinity(irq, desc);
800
801         } else if ((new->flags & IRQF_TRIGGER_MASK)
802                         && (new->flags & IRQF_TRIGGER_MASK)
803                                 != (desc->status & IRQ_TYPE_SENSE_MASK)) {
804                 /* hope the handler works with the actual trigger mode... */
805                 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
806                                 irq, (int)(desc->status & IRQ_TYPE_SENSE_MASK),
807                                 (int)(new->flags & IRQF_TRIGGER_MASK));
808         }
809
810         new->irq = irq;
811         *old_ptr = new;
812
813         /* Reset broken irq detection when installing new handler */
814         desc->irq_count = 0;
815         desc->irqs_unhandled = 0;
816
817         /*
818          * Check whether we disabled the irq via the spurious handler
819          * before. Reenable it and give it another chance.
820          */
821         if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
822                 desc->status &= ~IRQ_SPURIOUS_DISABLED;
823                 __enable_irq(desc, irq, false);
824         }
825
826         raw_spin_unlock_irqrestore(&desc->lock, flags);
827
828         /*
829          * Strictly no need to wake it up, but hung_task complains
830          * when no hard interrupt wakes the thread up.
831          */
832         if (new->thread)
833                 wake_up_process(new->thread);
834
835         register_irq_proc(irq, desc);
836         new->dir = NULL;
837         register_handler_proc(irq, new);
838
839         return 0;
840
841 mismatch:
842 #ifdef CONFIG_DEBUG_SHIRQ
843         if (!(new->flags & IRQF_PROBE_SHARED)) {
844                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
845                 if (old_name)
846                         printk(KERN_ERR "current handler: %s\n", old_name);
847                 dump_stack();
848         }
849 #endif
850         ret = -EBUSY;
851
852 out_thread:
853         raw_spin_unlock_irqrestore(&desc->lock, flags);
854         if (new->thread) {
855                 struct task_struct *t = new->thread;
856
857                 new->thread = NULL;
858                 if (likely(!test_bit(IRQTF_DIED, &new->thread_flags)))
859                         kthread_stop(t);
860                 put_task_struct(t);
861         }
862         return ret;
863 }
864
865 /**
866  *      setup_irq - setup an interrupt
867  *      @irq: Interrupt line to setup
868  *      @act: irqaction for the interrupt
869  *
870  * Used to statically setup interrupts in the early boot process.
871  */
872 int setup_irq(unsigned int irq, struct irqaction *act)
873 {
874         struct irq_desc *desc = irq_to_desc(irq);
875
876         return __setup_irq(irq, desc, act);
877 }
878 EXPORT_SYMBOL_GPL(setup_irq);
879
880  /*
881  * Internal function to unregister an irqaction - used to free
882  * regular and special interrupts that are part of the architecture.
883  */
884 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
885 {
886         struct irq_desc *desc = irq_to_desc(irq);
887         struct irqaction *action, **action_ptr;
888         unsigned long flags;
889
890         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
891
892         if (!desc)
893                 return NULL;
894
895         raw_spin_lock_irqsave(&desc->lock, flags);
896
897         /*
898          * There can be multiple actions per IRQ descriptor, find the right
899          * one based on the dev_id:
900          */
901         action_ptr = &desc->action;
902         for (;;) {
903                 action = *action_ptr;
904
905                 if (!action) {
906                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
907                         raw_spin_unlock_irqrestore(&desc->lock, flags);
908
909                         return NULL;
910                 }
911
912                 if (action->dev_id == dev_id)
913                         break;
914                 action_ptr = &action->next;
915         }
916
917         /* Found it - now remove it from the list of entries: */
918         *action_ptr = action->next;
919
920         /* Currently used only by UML, might disappear one day: */
921 #ifdef CONFIG_IRQ_RELEASE_METHOD
922         if (desc->irq_data.chip->release)
923                 desc->irq_data.chip->release(irq, dev_id);
924 #endif
925
926         /* If this was the last handler, shut down the IRQ line: */
927         if (!desc->action) {
928                 desc->status |= IRQ_DISABLED;
929                 if (desc->irq_data.chip->irq_shutdown)
930                         desc->irq_data.chip->irq_shutdown(&desc->irq_data);
931                 else
932                         desc->irq_data.chip->irq_disable(&desc->irq_data);
933         }
934
935 #ifdef CONFIG_SMP
936         /* make sure affinity_hint is cleaned up */
937         if (WARN_ON_ONCE(desc->affinity_hint))
938                 desc->affinity_hint = NULL;
939 #endif
940
941         raw_spin_unlock_irqrestore(&desc->lock, flags);
942
943         unregister_handler_proc(irq, action);
944
945         /* Make sure it's not being used on another CPU: */
946         synchronize_irq(irq);
947
948 #ifdef CONFIG_DEBUG_SHIRQ
949         /*
950          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
951          * event to happen even now it's being freed, so let's make sure that
952          * is so by doing an extra call to the handler ....
953          *
954          * ( We do this after actually deregistering it, to make sure that a
955          *   'real' IRQ doesn't run in * parallel with our fake. )
956          */
957         if (action->flags & IRQF_SHARED) {
958                 local_irq_save(flags);
959                 action->handler(irq, dev_id);
960                 local_irq_restore(flags);
961         }
962 #endif
963
964         if (action->thread) {
965                 if (!test_bit(IRQTF_DIED, &action->thread_flags))
966                         kthread_stop(action->thread);
967                 put_task_struct(action->thread);
968         }
969
970         return action;
971 }
972
973 /**
974  *      remove_irq - free an interrupt
975  *      @irq: Interrupt line to free
976  *      @act: irqaction for the interrupt
977  *
978  * Used to remove interrupts statically setup by the early boot process.
979  */
980 void remove_irq(unsigned int irq, struct irqaction *act)
981 {
982         __free_irq(irq, act->dev_id);
983 }
984 EXPORT_SYMBOL_GPL(remove_irq);
985
986 /**
987  *      free_irq - free an interrupt allocated with request_irq
988  *      @irq: Interrupt line to free
989  *      @dev_id: Device identity to free
990  *
991  *      Remove an interrupt handler. The handler is removed and if the
992  *      interrupt line is no longer in use by any driver it is disabled.
993  *      On a shared IRQ the caller must ensure the interrupt is disabled
994  *      on the card it drives before calling this function. The function
995  *      does not return until any executing interrupts for this IRQ
996  *      have completed.
997  *
998  *      This function must not be called from interrupt context.
999  */
1000 void free_irq(unsigned int irq, void *dev_id)
1001 {
1002         struct irq_desc *desc = irq_to_desc(irq);
1003
1004         if (!desc)
1005                 return;
1006
1007         chip_bus_lock(desc);
1008         kfree(__free_irq(irq, dev_id));
1009         chip_bus_sync_unlock(desc);
1010 }
1011 EXPORT_SYMBOL(free_irq);
1012
1013 /**
1014  *      request_threaded_irq - allocate an interrupt line
1015  *      @irq: Interrupt line to allocate
1016  *      @handler: Function to be called when the IRQ occurs.
1017  *                Primary handler for threaded interrupts
1018  *                If NULL and thread_fn != NULL the default
1019  *                primary handler is installed
1020  *      @thread_fn: Function called from the irq handler thread
1021  *                  If NULL, no irq thread is created
1022  *      @irqflags: Interrupt type flags
1023  *      @devname: An ascii name for the claiming device
1024  *      @dev_id: A cookie passed back to the handler function
1025  *
1026  *      This call allocates interrupt resources and enables the
1027  *      interrupt line and IRQ handling. From the point this
1028  *      call is made your handler function may be invoked. Since
1029  *      your handler function must clear any interrupt the board
1030  *      raises, you must take care both to initialise your hardware
1031  *      and to set up the interrupt handler in the right order.
1032  *
1033  *      If you want to set up a threaded irq handler for your device
1034  *      then you need to supply @handler and @thread_fn. @handler ist
1035  *      still called in hard interrupt context and has to check
1036  *      whether the interrupt originates from the device. If yes it
1037  *      needs to disable the interrupt on the device and return
1038  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1039  *      @thread_fn. This split handler design is necessary to support
1040  *      shared interrupts.
1041  *
1042  *      Dev_id must be globally unique. Normally the address of the
1043  *      device data structure is used as the cookie. Since the handler
1044  *      receives this value it makes sense to use it.
1045  *
1046  *      If your interrupt is shared you must pass a non NULL dev_id
1047  *      as this is required when freeing the interrupt.
1048  *
1049  *      Flags:
1050  *
1051  *      IRQF_SHARED             Interrupt is shared
1052  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
1053  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1054  *
1055  */
1056 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1057                          irq_handler_t thread_fn, unsigned long irqflags,
1058                          const char *devname, void *dev_id)
1059 {
1060         struct irqaction *action;
1061         struct irq_desc *desc;
1062         int retval;
1063
1064         /*
1065          * Sanity-check: shared interrupts must pass in a real dev-ID,
1066          * otherwise we'll have trouble later trying to figure out
1067          * which interrupt is which (messes up the interrupt freeing
1068          * logic etc).
1069          */
1070         if ((irqflags & IRQF_SHARED) && !dev_id)
1071                 return -EINVAL;
1072
1073         desc = irq_to_desc(irq);
1074         if (!desc)
1075                 return -EINVAL;
1076
1077         if (desc->status & IRQ_NOREQUEST)
1078                 return -EINVAL;
1079
1080         if (!handler) {
1081                 if (!thread_fn)
1082                         return -EINVAL;
1083                 handler = irq_default_primary_handler;
1084         }
1085
1086         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1087         if (!action)
1088                 return -ENOMEM;
1089
1090         action->handler = handler;
1091         action->thread_fn = thread_fn;
1092         action->flags = irqflags;
1093         action->name = devname;
1094         action->dev_id = dev_id;
1095
1096         chip_bus_lock(desc);
1097         retval = __setup_irq(irq, desc, action);
1098         chip_bus_sync_unlock(desc);
1099
1100         if (retval)
1101                 kfree(action);
1102
1103 #ifdef CONFIG_DEBUG_SHIRQ
1104         if (!retval && (irqflags & IRQF_SHARED)) {
1105                 /*
1106                  * It's a shared IRQ -- the driver ought to be prepared for it
1107                  * to happen immediately, so let's make sure....
1108                  * We disable the irq to make sure that a 'real' IRQ doesn't
1109                  * run in parallel with our fake.
1110                  */
1111                 unsigned long flags;
1112
1113                 disable_irq(irq);
1114                 local_irq_save(flags);
1115
1116                 handler(irq, dev_id);
1117
1118                 local_irq_restore(flags);
1119                 enable_irq(irq);
1120         }
1121 #endif
1122         return retval;
1123 }
1124 EXPORT_SYMBOL(request_threaded_irq);
1125
1126 /**
1127  *      request_any_context_irq - allocate an interrupt line
1128  *      @irq: Interrupt line to allocate
1129  *      @handler: Function to be called when the IRQ occurs.
1130  *                Threaded handler for threaded interrupts.
1131  *      @flags: Interrupt type flags
1132  *      @name: An ascii name for the claiming device
1133  *      @dev_id: A cookie passed back to the handler function
1134  *
1135  *      This call allocates interrupt resources and enables the
1136  *      interrupt line and IRQ handling. It selects either a
1137  *      hardirq or threaded handling method depending on the
1138  *      context.
1139  *
1140  *      On failure, it returns a negative value. On success,
1141  *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1142  */
1143 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1144                             unsigned long flags, const char *name, void *dev_id)
1145 {
1146         struct irq_desc *desc = irq_to_desc(irq);
1147         int ret;
1148
1149         if (!desc)
1150                 return -EINVAL;
1151
1152         if (desc->status & IRQ_NESTED_THREAD) {
1153                 ret = request_threaded_irq(irq, NULL, handler,
1154                                            flags, name, dev_id);
1155                 return !ret ? IRQC_IS_NESTED : ret;
1156         }
1157
1158         ret = request_irq(irq, handler, flags, name, dev_id);
1159         return !ret ? IRQC_IS_HARDIRQ : ret;
1160 }
1161 EXPORT_SYMBOL_GPL(request_any_context_irq);