Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
[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->chip ||
77             !desc->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->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->chip->set_affinity(irq, cpumask)) {
122                         cpumask_copy(desc->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->chip->set_affinity(irq, cpumask)) {
132                 cpumask_copy(desc->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 #ifndef CONFIG_AUTO_IRQ_AFFINITY
142 /*
143  * Generic version of the affinity autoselector.
144  */
145 static int setup_affinity(unsigned int irq, struct irq_desc *desc)
146 {
147         if (!irq_can_set_affinity(irq))
148                 return 0;
149
150         /*
151          * Preserve an userspace affinity setup, but make sure that
152          * one of the targets is online.
153          */
154         if (desc->status & (IRQ_AFFINITY_SET | IRQ_NO_BALANCING)) {
155                 if (cpumask_any_and(desc->affinity, cpu_online_mask)
156                     < nr_cpu_ids)
157                         goto set_affinity;
158                 else
159                         desc->status &= ~IRQ_AFFINITY_SET;
160         }
161
162         cpumask_and(desc->affinity, cpu_online_mask, irq_default_affinity);
163 set_affinity:
164         desc->chip->set_affinity(irq, desc->affinity);
165
166         return 0;
167 }
168 #else
169 static inline int setup_affinity(unsigned int irq, struct irq_desc *d)
170 {
171         return irq_select_affinity(irq);
172 }
173 #endif
174
175 /*
176  * Called when affinity is set via /proc/irq
177  */
178 int irq_select_affinity_usr(unsigned int irq)
179 {
180         struct irq_desc *desc = irq_to_desc(irq);
181         unsigned long flags;
182         int ret;
183
184         raw_spin_lock_irqsave(&desc->lock, flags);
185         ret = setup_affinity(irq, desc);
186         if (!ret)
187                 irq_set_thread_affinity(desc);
188         raw_spin_unlock_irqrestore(&desc->lock, flags);
189
190         return ret;
191 }
192
193 #else
194 static inline int setup_affinity(unsigned int irq, struct irq_desc *desc)
195 {
196         return 0;
197 }
198 #endif
199
200 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
201 {
202         if (suspend) {
203                 if (!desc->action || (desc->action->flags & IRQF_TIMER))
204                         return;
205                 desc->status |= IRQ_SUSPENDED;
206         }
207
208         if (!desc->depth++) {
209                 desc->status |= IRQ_DISABLED;
210                 desc->chip->disable(irq);
211         }
212 }
213
214 /**
215  *      disable_irq_nosync - disable an irq without waiting
216  *      @irq: Interrupt to disable
217  *
218  *      Disable the selected interrupt line.  Disables and Enables are
219  *      nested.
220  *      Unlike disable_irq(), this function does not ensure existing
221  *      instances of the IRQ handler have completed before returning.
222  *
223  *      This function may be called from IRQ context.
224  */
225 void disable_irq_nosync(unsigned int irq)
226 {
227         struct irq_desc *desc = irq_to_desc(irq);
228         unsigned long flags;
229
230         if (!desc)
231                 return;
232
233         chip_bus_lock(irq, desc);
234         raw_spin_lock_irqsave(&desc->lock, flags);
235         __disable_irq(desc, irq, false);
236         raw_spin_unlock_irqrestore(&desc->lock, flags);
237         chip_bus_sync_unlock(irq, desc);
238 }
239 EXPORT_SYMBOL(disable_irq_nosync);
240
241 /**
242  *      disable_irq - disable an irq and wait for completion
243  *      @irq: Interrupt to disable
244  *
245  *      Disable the selected interrupt line.  Enables and Disables are
246  *      nested.
247  *      This function waits for any pending IRQ handlers for this interrupt
248  *      to complete before returning. If you use this function while
249  *      holding a resource the IRQ handler may need you will deadlock.
250  *
251  *      This function may be called - with care - from IRQ context.
252  */
253 void disable_irq(unsigned int irq)
254 {
255         struct irq_desc *desc = irq_to_desc(irq);
256
257         if (!desc)
258                 return;
259
260         disable_irq_nosync(irq);
261         if (desc->action)
262                 synchronize_irq(irq);
263 }
264 EXPORT_SYMBOL(disable_irq);
265
266 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
267 {
268         if (resume)
269                 desc->status &= ~IRQ_SUSPENDED;
270
271         switch (desc->depth) {
272         case 0:
273  err_out:
274                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
275                 break;
276         case 1: {
277                 unsigned int status = desc->status & ~IRQ_DISABLED;
278
279                 if (desc->status & IRQ_SUSPENDED)
280                         goto err_out;
281                 /* Prevent probing on this irq: */
282                 desc->status = status | IRQ_NOPROBE;
283                 check_irq_resend(desc, irq);
284                 /* fall-through */
285         }
286         default:
287                 desc->depth--;
288         }
289 }
290
291 /**
292  *      enable_irq - enable handling of an irq
293  *      @irq: Interrupt to enable
294  *
295  *      Undoes the effect of one call to disable_irq().  If this
296  *      matches the last disable, processing of interrupts on this
297  *      IRQ line is re-enabled.
298  *
299  *      This function may be called from IRQ context only when
300  *      desc->chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
301  */
302 void enable_irq(unsigned int irq)
303 {
304         struct irq_desc *desc = irq_to_desc(irq);
305         unsigned long flags;
306
307         if (!desc)
308                 return;
309
310         chip_bus_lock(irq, desc);
311         raw_spin_lock_irqsave(&desc->lock, flags);
312         __enable_irq(desc, irq, false);
313         raw_spin_unlock_irqrestore(&desc->lock, flags);
314         chip_bus_sync_unlock(irq, desc);
315 }
316 EXPORT_SYMBOL(enable_irq);
317
318 static int set_irq_wake_real(unsigned int irq, unsigned int on)
319 {
320         struct irq_desc *desc = irq_to_desc(irq);
321         int ret = -ENXIO;
322
323         if (desc->chip->set_wake)
324                 ret = desc->chip->set_wake(irq, on);
325
326         return ret;
327 }
328
329 /**
330  *      set_irq_wake - control irq power management wakeup
331  *      @irq:   interrupt to control
332  *      @on:    enable/disable power management wakeup
333  *
334  *      Enable/disable power management wakeup mode, which is
335  *      disabled by default.  Enables and disables must match,
336  *      just as they match for non-wakeup mode support.
337  *
338  *      Wakeup mode lets this IRQ wake the system from sleep
339  *      states like "suspend to RAM".
340  */
341 int set_irq_wake(unsigned int irq, unsigned int on)
342 {
343         struct irq_desc *desc = irq_to_desc(irq);
344         unsigned long flags;
345         int ret = 0;
346
347         /* wakeup-capable irqs can be shared between drivers that
348          * don't need to have the same sleep mode behaviors.
349          */
350         raw_spin_lock_irqsave(&desc->lock, flags);
351         if (on) {
352                 if (desc->wake_depth++ == 0) {
353                         ret = set_irq_wake_real(irq, on);
354                         if (ret)
355                                 desc->wake_depth = 0;
356                         else
357                                 desc->status |= IRQ_WAKEUP;
358                 }
359         } else {
360                 if (desc->wake_depth == 0) {
361                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
362                 } else if (--desc->wake_depth == 0) {
363                         ret = set_irq_wake_real(irq, on);
364                         if (ret)
365                                 desc->wake_depth = 1;
366                         else
367                                 desc->status &= ~IRQ_WAKEUP;
368                 }
369         }
370
371         raw_spin_unlock_irqrestore(&desc->lock, flags);
372         return ret;
373 }
374 EXPORT_SYMBOL(set_irq_wake);
375
376 /*
377  * Internal function that tells the architecture code whether a
378  * particular irq has been exclusively allocated or is available
379  * for driver use.
380  */
381 int can_request_irq(unsigned int irq, unsigned long irqflags)
382 {
383         struct irq_desc *desc = irq_to_desc(irq);
384         struct irqaction *action;
385         unsigned long flags;
386
387         if (!desc)
388                 return 0;
389
390         if (desc->status & IRQ_NOREQUEST)
391                 return 0;
392
393         raw_spin_lock_irqsave(&desc->lock, flags);
394         action = desc->action;
395         if (action)
396                 if (irqflags & action->flags & IRQF_SHARED)
397                         action = NULL;
398
399         raw_spin_unlock_irqrestore(&desc->lock, flags);
400
401         return !action;
402 }
403
404 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
405 {
406         /*
407          * If the architecture still has not overriden
408          * the flow handler then zap the default. This
409          * should catch incorrect flow-type setting.
410          */
411         if (desc->handle_irq == &handle_bad_irq)
412                 desc->handle_irq = NULL;
413 }
414
415 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
416                 unsigned long flags)
417 {
418         int ret;
419         struct irq_chip *chip = desc->chip;
420
421         if (!chip || !chip->set_type) {
422                 /*
423                  * IRQF_TRIGGER_* but the PIC does not support multiple
424                  * flow-types?
425                  */
426                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
427                                 chip ? (chip->name ? : "unknown") : "unknown");
428                 return 0;
429         }
430
431         /* caller masked out all except trigger mode flags */
432         ret = chip->set_type(irq, flags);
433
434         if (ret)
435                 pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
436                                 (int)flags, irq, chip->set_type);
437         else {
438                 if (flags & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
439                         flags |= IRQ_LEVEL;
440                 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
441                 desc->status &= ~(IRQ_LEVEL | IRQ_TYPE_SENSE_MASK);
442                 desc->status |= flags;
443         }
444
445         return ret;
446 }
447
448 /*
449  * Default primary interrupt handler for threaded interrupts. Is
450  * assigned as primary handler when request_threaded_irq is called
451  * with handler == NULL. Useful for oneshot interrupts.
452  */
453 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
454 {
455         return IRQ_WAKE_THREAD;
456 }
457
458 /*
459  * Primary handler for nested threaded interrupts. Should never be
460  * called.
461  */
462 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
463 {
464         WARN(1, "Primary handler called for nested irq %d\n", irq);
465         return IRQ_NONE;
466 }
467
468 static int irq_wait_for_interrupt(struct irqaction *action)
469 {
470         while (!kthread_should_stop()) {
471                 set_current_state(TASK_INTERRUPTIBLE);
472
473                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
474                                        &action->thread_flags)) {
475                         __set_current_state(TASK_RUNNING);
476                         return 0;
477                 }
478                 schedule();
479         }
480         return -1;
481 }
482
483 /*
484  * Oneshot interrupts keep the irq line masked until the threaded
485  * handler finished. unmask if the interrupt has not been disabled and
486  * is marked MASKED.
487  */
488 static void irq_finalize_oneshot(unsigned int irq, struct irq_desc *desc)
489 {
490 again:
491         chip_bus_lock(irq, desc);
492         raw_spin_lock_irq(&desc->lock);
493
494         /*
495          * Implausible though it may be we need to protect us against
496          * the following scenario:
497          *
498          * The thread is faster done than the hard interrupt handler
499          * on the other CPU. If we unmask the irq line then the
500          * interrupt can come in again and masks the line, leaves due
501          * to IRQ_INPROGRESS and the irq line is masked forever.
502          */
503         if (unlikely(desc->status & IRQ_INPROGRESS)) {
504                 raw_spin_unlock_irq(&desc->lock);
505                 chip_bus_sync_unlock(irq, desc);
506                 cpu_relax();
507                 goto again;
508         }
509
510         if (!(desc->status & IRQ_DISABLED) && (desc->status & IRQ_MASKED)) {
511                 desc->status &= ~IRQ_MASKED;
512                 desc->chip->unmask(irq);
513         }
514         raw_spin_unlock_irq(&desc->lock);
515         chip_bus_sync_unlock(irq, desc);
516 }
517
518 #ifdef CONFIG_SMP
519 /*
520  * Check whether we need to change the affinity of the interrupt thread.
521  */
522 static void
523 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
524 {
525         cpumask_var_t mask;
526
527         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
528                 return;
529
530         /*
531          * In case we are out of memory we set IRQTF_AFFINITY again and
532          * try again next time
533          */
534         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
535                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
536                 return;
537         }
538
539         raw_spin_lock_irq(&desc->lock);
540         cpumask_copy(mask, desc->affinity);
541         raw_spin_unlock_irq(&desc->lock);
542
543         set_cpus_allowed_ptr(current, mask);
544         free_cpumask_var(mask);
545 }
546 #else
547 static inline void
548 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
549 #endif
550
551 /*
552  * Interrupt handler thread
553  */
554 static int irq_thread(void *data)
555 {
556         struct sched_param param = { .sched_priority = MAX_USER_RT_PRIO/2, };
557         struct irqaction *action = data;
558         struct irq_desc *desc = irq_to_desc(action->irq);
559         int wake, oneshot = desc->status & IRQ_ONESHOT;
560
561         sched_setscheduler(current, SCHED_FIFO, &param);
562         current->irqaction = action;
563
564         while (!irq_wait_for_interrupt(action)) {
565
566                 irq_thread_check_affinity(desc, action);
567
568                 atomic_inc(&desc->threads_active);
569
570                 raw_spin_lock_irq(&desc->lock);
571                 if (unlikely(desc->status & IRQ_DISABLED)) {
572                         /*
573                          * CHECKME: We might need a dedicated
574                          * IRQ_THREAD_PENDING flag here, which
575                          * retriggers the thread in check_irq_resend()
576                          * but AFAICT IRQ_PENDING should be fine as it
577                          * retriggers the interrupt itself --- tglx
578                          */
579                         desc->status |= IRQ_PENDING;
580                         raw_spin_unlock_irq(&desc->lock);
581                 } else {
582                         raw_spin_unlock_irq(&desc->lock);
583
584                         action->thread_fn(action->irq, action->dev_id);
585
586                         if (oneshot)
587                                 irq_finalize_oneshot(action->irq, desc);
588                 }
589
590                 wake = atomic_dec_and_test(&desc->threads_active);
591
592                 if (wake && waitqueue_active(&desc->wait_for_threads))
593                         wake_up(&desc->wait_for_threads);
594         }
595
596         /*
597          * Clear irqaction. Otherwise exit_irq_thread() would make
598          * fuzz about an active irq thread going into nirvana.
599          */
600         current->irqaction = NULL;
601         return 0;
602 }
603
604 /*
605  * Called from do_exit()
606  */
607 void exit_irq_thread(void)
608 {
609         struct task_struct *tsk = current;
610
611         if (!tsk->irqaction)
612                 return;
613
614         printk(KERN_ERR
615                "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
616                tsk->comm ? tsk->comm : "", tsk->pid, tsk->irqaction->irq);
617
618         /*
619          * Set the THREAD DIED flag to prevent further wakeups of the
620          * soon to be gone threaded handler.
621          */
622         set_bit(IRQTF_DIED, &tsk->irqaction->flags);
623 }
624
625 /*
626  * Internal function to register an irqaction - typically used to
627  * allocate special interrupts that are part of the architecture.
628  */
629 static int
630 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
631 {
632         struct irqaction *old, **old_ptr;
633         const char *old_name = NULL;
634         unsigned long flags;
635         int nested, shared = 0;
636         int ret;
637
638         if (!desc)
639                 return -EINVAL;
640
641         if (desc->chip == &no_irq_chip)
642                 return -ENOSYS;
643         /*
644          * Some drivers like serial.c use request_irq() heavily,
645          * so we have to be careful not to interfere with a
646          * running system.
647          */
648         if (new->flags & IRQF_SAMPLE_RANDOM) {
649                 /*
650                  * This function might sleep, we want to call it first,
651                  * outside of the atomic block.
652                  * Yes, this might clear the entropy pool if the wrong
653                  * driver is attempted to be loaded, without actually
654                  * installing a new handler, but is this really a problem,
655                  * only the sysadmin is able to do this.
656                  */
657                 rand_initialize_irq(irq);
658         }
659
660         /* Oneshot interrupts are not allowed with shared */
661         if ((new->flags & IRQF_ONESHOT) && (new->flags & IRQF_SHARED))
662                 return -EINVAL;
663
664         /*
665          * Check whether the interrupt nests into another interrupt
666          * thread.
667          */
668         nested = desc->status & IRQ_NESTED_THREAD;
669         if (nested) {
670                 if (!new->thread_fn)
671                         return -EINVAL;
672                 /*
673                  * Replace the primary handler which was provided from
674                  * the driver for non nested interrupt handling by the
675                  * dummy function which warns when called.
676                  */
677                 new->handler = irq_nested_primary_handler;
678         }
679
680         /*
681          * Create a handler thread when a thread function is supplied
682          * and the interrupt does not nest into another interrupt
683          * thread.
684          */
685         if (new->thread_fn && !nested) {
686                 struct task_struct *t;
687
688                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
689                                    new->name);
690                 if (IS_ERR(t))
691                         return PTR_ERR(t);
692                 /*
693                  * We keep the reference to the task struct even if
694                  * the thread dies to avoid that the interrupt code
695                  * references an already freed task_struct.
696                  */
697                 get_task_struct(t);
698                 new->thread = t;
699         }
700
701         /*
702          * The following block of code has to be executed atomically
703          */
704         raw_spin_lock_irqsave(&desc->lock, flags);
705         old_ptr = &desc->action;
706         old = *old_ptr;
707         if (old) {
708                 /*
709                  * Can't share interrupts unless both agree to and are
710                  * the same type (level, edge, polarity). So both flag
711                  * fields must have IRQF_SHARED set and the bits which
712                  * set the trigger type must match.
713                  */
714                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
715                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
716                         old_name = old->name;
717                         goto mismatch;
718                 }
719
720 #if defined(CONFIG_IRQ_PER_CPU)
721                 /* All handlers must agree on per-cpuness */
722                 if ((old->flags & IRQF_PERCPU) !=
723                     (new->flags & IRQF_PERCPU))
724                         goto mismatch;
725 #endif
726
727                 /* add new interrupt at end of irq queue */
728                 do {
729                         old_ptr = &old->next;
730                         old = *old_ptr;
731                 } while (old);
732                 shared = 1;
733         }
734
735         if (!shared) {
736                 irq_chip_set_defaults(desc->chip);
737
738                 init_waitqueue_head(&desc->wait_for_threads);
739
740                 /* Setup the type (level, edge polarity) if configured: */
741                 if (new->flags & IRQF_TRIGGER_MASK) {
742                         ret = __irq_set_trigger(desc, irq,
743                                         new->flags & IRQF_TRIGGER_MASK);
744
745                         if (ret)
746                                 goto out_thread;
747                 } else
748                         compat_irq_chip_set_default_handler(desc);
749 #if defined(CONFIG_IRQ_PER_CPU)
750                 if (new->flags & IRQF_PERCPU)
751                         desc->status |= IRQ_PER_CPU;
752 #endif
753
754                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING | IRQ_ONESHOT |
755                                   IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
756
757                 if (new->flags & IRQF_ONESHOT)
758                         desc->status |= IRQ_ONESHOT;
759
760                 if (!(desc->status & IRQ_NOAUTOEN)) {
761                         desc->depth = 0;
762                         desc->status &= ~IRQ_DISABLED;
763                         desc->chip->startup(irq);
764                 } else
765                         /* Undo nested disables: */
766                         desc->depth = 1;
767
768                 /* Exclude IRQ from balancing if requested */
769                 if (new->flags & IRQF_NOBALANCING)
770                         desc->status |= IRQ_NO_BALANCING;
771
772                 /* Set default affinity mask once everything is setup */
773                 setup_affinity(irq, desc);
774
775         } else if ((new->flags & IRQF_TRIGGER_MASK)
776                         && (new->flags & IRQF_TRIGGER_MASK)
777                                 != (desc->status & IRQ_TYPE_SENSE_MASK)) {
778                 /* hope the handler works with the actual trigger mode... */
779                 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
780                                 irq, (int)(desc->status & IRQ_TYPE_SENSE_MASK),
781                                 (int)(new->flags & IRQF_TRIGGER_MASK));
782         }
783
784         new->irq = irq;
785         *old_ptr = new;
786
787         /* Reset broken irq detection when installing new handler */
788         desc->irq_count = 0;
789         desc->irqs_unhandled = 0;
790
791         /*
792          * Check whether we disabled the irq via the spurious handler
793          * before. Reenable it and give it another chance.
794          */
795         if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
796                 desc->status &= ~IRQ_SPURIOUS_DISABLED;
797                 __enable_irq(desc, irq, false);
798         }
799
800         raw_spin_unlock_irqrestore(&desc->lock, flags);
801
802         /*
803          * Strictly no need to wake it up, but hung_task complains
804          * when no hard interrupt wakes the thread up.
805          */
806         if (new->thread)
807                 wake_up_process(new->thread);
808
809         register_irq_proc(irq, desc);
810         new->dir = NULL;
811         register_handler_proc(irq, new);
812
813         return 0;
814
815 mismatch:
816 #ifdef CONFIG_DEBUG_SHIRQ
817         if (!(new->flags & IRQF_PROBE_SHARED)) {
818                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
819                 if (old_name)
820                         printk(KERN_ERR "current handler: %s\n", old_name);
821                 dump_stack();
822         }
823 #endif
824         ret = -EBUSY;
825
826 out_thread:
827         raw_spin_unlock_irqrestore(&desc->lock, flags);
828         if (new->thread) {
829                 struct task_struct *t = new->thread;
830
831                 new->thread = NULL;
832                 if (likely(!test_bit(IRQTF_DIED, &new->thread_flags)))
833                         kthread_stop(t);
834                 put_task_struct(t);
835         }
836         return ret;
837 }
838
839 /**
840  *      setup_irq - setup an interrupt
841  *      @irq: Interrupt line to setup
842  *      @act: irqaction for the interrupt
843  *
844  * Used to statically setup interrupts in the early boot process.
845  */
846 int setup_irq(unsigned int irq, struct irqaction *act)
847 {
848         struct irq_desc *desc = irq_to_desc(irq);
849
850         return __setup_irq(irq, desc, act);
851 }
852 EXPORT_SYMBOL_GPL(setup_irq);
853
854  /*
855  * Internal function to unregister an irqaction - used to free
856  * regular and special interrupts that are part of the architecture.
857  */
858 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
859 {
860         struct irq_desc *desc = irq_to_desc(irq);
861         struct irqaction *action, **action_ptr;
862         unsigned long flags;
863
864         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
865
866         if (!desc)
867                 return NULL;
868
869         raw_spin_lock_irqsave(&desc->lock, flags);
870
871         /*
872          * There can be multiple actions per IRQ descriptor, find the right
873          * one based on the dev_id:
874          */
875         action_ptr = &desc->action;
876         for (;;) {
877                 action = *action_ptr;
878
879                 if (!action) {
880                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
881                         raw_spin_unlock_irqrestore(&desc->lock, flags);
882
883                         return NULL;
884                 }
885
886                 if (action->dev_id == dev_id)
887                         break;
888                 action_ptr = &action->next;
889         }
890
891         /* Found it - now remove it from the list of entries: */
892         *action_ptr = action->next;
893
894         /* Currently used only by UML, might disappear one day: */
895 #ifdef CONFIG_IRQ_RELEASE_METHOD
896         if (desc->chip->release)
897                 desc->chip->release(irq, dev_id);
898 #endif
899
900         /* If this was the last handler, shut down the IRQ line: */
901         if (!desc->action) {
902                 desc->status |= IRQ_DISABLED;
903                 if (desc->chip->shutdown)
904                         desc->chip->shutdown(irq);
905                 else
906                         desc->chip->disable(irq);
907         }
908
909         raw_spin_unlock_irqrestore(&desc->lock, flags);
910
911         unregister_handler_proc(irq, action);
912
913         /* Make sure it's not being used on another CPU: */
914         synchronize_irq(irq);
915
916 #ifdef CONFIG_DEBUG_SHIRQ
917         /*
918          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
919          * event to happen even now it's being freed, so let's make sure that
920          * is so by doing an extra call to the handler ....
921          *
922          * ( We do this after actually deregistering it, to make sure that a
923          *   'real' IRQ doesn't run in * parallel with our fake. )
924          */
925         if (action->flags & IRQF_SHARED) {
926                 local_irq_save(flags);
927                 action->handler(irq, dev_id);
928                 local_irq_restore(flags);
929         }
930 #endif
931
932         if (action->thread) {
933                 if (!test_bit(IRQTF_DIED, &action->thread_flags))
934                         kthread_stop(action->thread);
935                 put_task_struct(action->thread);
936         }
937
938         return action;
939 }
940
941 /**
942  *      remove_irq - free an interrupt
943  *      @irq: Interrupt line to free
944  *      @act: irqaction for the interrupt
945  *
946  * Used to remove interrupts statically setup by the early boot process.
947  */
948 void remove_irq(unsigned int irq, struct irqaction *act)
949 {
950         __free_irq(irq, act->dev_id);
951 }
952 EXPORT_SYMBOL_GPL(remove_irq);
953
954 /**
955  *      free_irq - free an interrupt allocated with request_irq
956  *      @irq: Interrupt line to free
957  *      @dev_id: Device identity to free
958  *
959  *      Remove an interrupt handler. The handler is removed and if the
960  *      interrupt line is no longer in use by any driver it is disabled.
961  *      On a shared IRQ the caller must ensure the interrupt is disabled
962  *      on the card it drives before calling this function. The function
963  *      does not return until any executing interrupts for this IRQ
964  *      have completed.
965  *
966  *      This function must not be called from interrupt context.
967  */
968 void free_irq(unsigned int irq, void *dev_id)
969 {
970         struct irq_desc *desc = irq_to_desc(irq);
971
972         if (!desc)
973                 return;
974
975         chip_bus_lock(irq, desc);
976         kfree(__free_irq(irq, dev_id));
977         chip_bus_sync_unlock(irq, desc);
978 }
979 EXPORT_SYMBOL(free_irq);
980
981 /**
982  *      request_threaded_irq - allocate an interrupt line
983  *      @irq: Interrupt line to allocate
984  *      @handler: Function to be called when the IRQ occurs.
985  *                Primary handler for threaded interrupts
986  *                If NULL and thread_fn != NULL the default
987  *                primary handler is installed
988  *      @thread_fn: Function called from the irq handler thread
989  *                  If NULL, no irq thread is created
990  *      @irqflags: Interrupt type flags
991  *      @devname: An ascii name for the claiming device
992  *      @dev_id: A cookie passed back to the handler function
993  *
994  *      This call allocates interrupt resources and enables the
995  *      interrupt line and IRQ handling. From the point this
996  *      call is made your handler function may be invoked. Since
997  *      your handler function must clear any interrupt the board
998  *      raises, you must take care both to initialise your hardware
999  *      and to set up the interrupt handler in the right order.
1000  *
1001  *      If you want to set up a threaded irq handler for your device
1002  *      then you need to supply @handler and @thread_fn. @handler ist
1003  *      still called in hard interrupt context and has to check
1004  *      whether the interrupt originates from the device. If yes it
1005  *      needs to disable the interrupt on the device and return
1006  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1007  *      @thread_fn. This split handler design is necessary to support
1008  *      shared interrupts.
1009  *
1010  *      Dev_id must be globally unique. Normally the address of the
1011  *      device data structure is used as the cookie. Since the handler
1012  *      receives this value it makes sense to use it.
1013  *
1014  *      If your interrupt is shared you must pass a non NULL dev_id
1015  *      as this is required when freeing the interrupt.
1016  *
1017  *      Flags:
1018  *
1019  *      IRQF_SHARED             Interrupt is shared
1020  *      IRQF_DISABLED   Disable local interrupts while processing
1021  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
1022  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1023  *
1024  */
1025 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1026                          irq_handler_t thread_fn, unsigned long irqflags,
1027                          const char *devname, void *dev_id)
1028 {
1029         struct irqaction *action;
1030         struct irq_desc *desc;
1031         int retval;
1032
1033         /*
1034          * handle_IRQ_event() always ignores IRQF_DISABLED except for
1035          * the _first_ irqaction (sigh).  That can cause oopsing, but
1036          * the behavior is classified as "will not fix" so we need to
1037          * start nudging drivers away from using that idiom.
1038          */
1039         if ((irqflags & (IRQF_SHARED|IRQF_DISABLED)) ==
1040                                         (IRQF_SHARED|IRQF_DISABLED)) {
1041                 pr_warning(
1042                   "IRQ %d/%s: IRQF_DISABLED is not guaranteed on shared IRQs\n",
1043                         irq, devname);
1044         }
1045
1046 #ifdef CONFIG_LOCKDEP
1047         /*
1048          * Lockdep wants atomic interrupt handlers:
1049          */
1050         irqflags |= IRQF_DISABLED;
1051 #endif
1052         /*
1053          * Sanity-check: shared interrupts must pass in a real dev-ID,
1054          * otherwise we'll have trouble later trying to figure out
1055          * which interrupt is which (messes up the interrupt freeing
1056          * logic etc).
1057          */
1058         if ((irqflags & IRQF_SHARED) && !dev_id)
1059                 return -EINVAL;
1060
1061         desc = irq_to_desc(irq);
1062         if (!desc)
1063                 return -EINVAL;
1064
1065         if (desc->status & IRQ_NOREQUEST)
1066                 return -EINVAL;
1067
1068         if (!handler) {
1069                 if (!thread_fn)
1070                         return -EINVAL;
1071                 handler = irq_default_primary_handler;
1072         }
1073
1074         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1075         if (!action)
1076                 return -ENOMEM;
1077
1078         action->handler = handler;
1079         action->thread_fn = thread_fn;
1080         action->flags = irqflags;
1081         action->name = devname;
1082         action->dev_id = dev_id;
1083
1084         chip_bus_lock(irq, desc);
1085         retval = __setup_irq(irq, desc, action);
1086         chip_bus_sync_unlock(irq, desc);
1087
1088         if (retval)
1089                 kfree(action);
1090
1091 #ifdef CONFIG_DEBUG_SHIRQ
1092         if (!retval && (irqflags & IRQF_SHARED)) {
1093                 /*
1094                  * It's a shared IRQ -- the driver ought to be prepared for it
1095                  * to happen immediately, so let's make sure....
1096                  * We disable the irq to make sure that a 'real' IRQ doesn't
1097                  * run in parallel with our fake.
1098                  */
1099                 unsigned long flags;
1100
1101                 disable_irq(irq);
1102                 local_irq_save(flags);
1103
1104                 handler(irq, dev_id);
1105
1106                 local_irq_restore(flags);
1107                 enable_irq(irq);
1108         }
1109 #endif
1110         return retval;
1111 }
1112 EXPORT_SYMBOL(request_threaded_irq);