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