6df49218632a2ec044ccd82003f65b70ec02bd04
[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/module.h>
12 #include <linux/random.h>
13 #include <linux/interrupt.h>
14 #include <linux/slab.h>
15
16 #include "internals.h"
17
18 #ifdef CONFIG_SMP
19
20 cpumask_t irq_default_affinity = CPU_MASK_ALL;
21
22 /**
23  *      synchronize_irq - wait for pending IRQ handlers (on other CPUs)
24  *      @irq: interrupt number to wait for
25  *
26  *      This function waits for any pending IRQ handlers for this interrupt
27  *      to complete before returning. If you use this function while
28  *      holding a resource the IRQ handler may need you will deadlock.
29  *
30  *      This function may be called - with care - from IRQ context.
31  */
32 void synchronize_irq(unsigned int irq)
33 {
34         struct irq_desc *desc = irq_to_desc(irq);
35         unsigned int status;
36
37         if (!desc)
38                 return;
39
40         do {
41                 unsigned long flags;
42
43                 /*
44                  * Wait until we're out of the critical section.  This might
45                  * give the wrong answer due to the lack of memory barriers.
46                  */
47                 while (desc->status & IRQ_INPROGRESS)
48                         cpu_relax();
49
50                 /* Ok, that indicated we're done: double-check carefully. */
51                 spin_lock_irqsave(&desc->lock, flags);
52                 status = desc->status;
53                 spin_unlock_irqrestore(&desc->lock, flags);
54
55                 /* Oops, that failed? */
56         } while (status & IRQ_INPROGRESS);
57 }
58 EXPORT_SYMBOL(synchronize_irq);
59
60 /**
61  *      irq_can_set_affinity - Check if the affinity of a given irq can be set
62  *      @irq:           Interrupt to check
63  *
64  */
65 int irq_can_set_affinity(unsigned int irq)
66 {
67         struct irq_desc *desc = irq_to_desc(irq);
68
69         if (CHECK_IRQ_PER_CPU(desc->status) || !desc->chip ||
70             !desc->chip->set_affinity)
71                 return 0;
72
73         return 1;
74 }
75
76 /**
77  *      irq_set_affinity - Set the irq affinity of a given irq
78  *      @irq:           Interrupt to set affinity
79  *      @cpumask:       cpumask
80  *
81  */
82 int irq_set_affinity(unsigned int irq, cpumask_t cpumask)
83 {
84         struct irq_desc *desc = irq_to_desc(irq);
85
86         if (!desc->chip->set_affinity)
87                 return -EINVAL;
88
89         set_balance_irq_affinity(irq, cpumask);
90
91 #ifdef CONFIG_GENERIC_PENDING_IRQ
92         if (desc->status & IRQ_MOVE_PCNTXT) {
93                 unsigned long flags;
94
95                 spin_lock_irqsave(&desc->lock, flags);
96                 desc->chip->set_affinity(irq, cpumask);
97                 spin_unlock_irqrestore(&desc->lock, flags);
98         } else
99                 set_pending_irq(irq, cpumask);
100 #else
101         desc->affinity = cpumask;
102         desc->chip->set_affinity(irq, cpumask);
103 #endif
104         return 0;
105 }
106
107 #ifndef CONFIG_AUTO_IRQ_AFFINITY
108 /*
109  * Generic version of the affinity autoselector.
110  */
111 int irq_select_affinity(unsigned int irq)
112 {
113         cpumask_t mask;
114         struct irq_desc *desc;
115
116         if (!irq_can_set_affinity(irq))
117                 return 0;
118
119         cpus_and(mask, cpu_online_map, irq_default_affinity);
120
121         desc = irq_to_desc(irq);
122         desc->affinity = mask;
123         desc->chip->set_affinity(irq, mask);
124
125         set_balance_irq_affinity(irq, mask);
126         return 0;
127 }
128 #endif
129
130 #endif
131
132 /**
133  *      disable_irq_nosync - disable an irq without waiting
134  *      @irq: Interrupt to disable
135  *
136  *      Disable the selected interrupt line.  Disables and Enables are
137  *      nested.
138  *      Unlike disable_irq(), this function does not ensure existing
139  *      instances of the IRQ handler have completed before returning.
140  *
141  *      This function may be called from IRQ context.
142  */
143 void disable_irq_nosync(unsigned int irq)
144 {
145         struct irq_desc *desc;
146         unsigned long flags;
147
148         desc = irq_to_desc(irq);
149         if (!desc)
150                 return;
151
152         spin_lock_irqsave(&desc->lock, flags);
153         if (!desc->depth++) {
154                 desc->status |= IRQ_DISABLED;
155                 desc->chip->disable(irq);
156         }
157         spin_unlock_irqrestore(&desc->lock, flags);
158 }
159 EXPORT_SYMBOL(disable_irq_nosync);
160
161 /**
162  *      disable_irq - disable an irq and wait for completion
163  *      @irq: Interrupt to disable
164  *
165  *      Disable the selected interrupt line.  Enables and Disables are
166  *      nested.
167  *      This function waits for any pending IRQ handlers for this interrupt
168  *      to complete before returning. If you use this function while
169  *      holding a resource the IRQ handler may need you will deadlock.
170  *
171  *      This function may be called - with care - from IRQ context.
172  */
173 void disable_irq(unsigned int irq)
174 {
175         struct irq_desc *desc;
176
177         desc = irq_to_desc(irq);
178         if (!desc)
179                 return;
180
181         disable_irq_nosync(irq);
182         if (desc->action)
183                 synchronize_irq(irq);
184 }
185 EXPORT_SYMBOL(disable_irq);
186
187 static void __enable_irq(struct irq_desc *desc, unsigned int irq)
188 {
189         switch (desc->depth) {
190         case 0:
191                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
192                 break;
193         case 1: {
194                 unsigned int status = desc->status & ~IRQ_DISABLED;
195
196                 /* Prevent probing on this irq: */
197                 desc->status = status | IRQ_NOPROBE;
198                 check_irq_resend(desc, irq);
199                 /* fall-through */
200         }
201         default:
202                 desc->depth--;
203         }
204 }
205
206 /**
207  *      enable_irq - enable handling of an irq
208  *      @irq: Interrupt to enable
209  *
210  *      Undoes the effect of one call to disable_irq().  If this
211  *      matches the last disable, processing of interrupts on this
212  *      IRQ line is re-enabled.
213  *
214  *      This function may be called from IRQ context.
215  */
216 void enable_irq(unsigned int irq)
217 {
218         struct irq_desc *desc;
219         unsigned long flags;
220
221         desc = irq_to_desc(irq);
222         if (!desc)
223                 return;
224
225         spin_lock_irqsave(&desc->lock, flags);
226         __enable_irq(desc, irq);
227         spin_unlock_irqrestore(&desc->lock, flags);
228 }
229 EXPORT_SYMBOL(enable_irq);
230
231 static int set_irq_wake_real(unsigned int irq, unsigned int on)
232 {
233         struct irq_desc *desc = irq_to_desc(irq);
234         int ret = -ENXIO;
235
236         if (desc->chip->set_wake)
237                 ret = desc->chip->set_wake(irq, on);
238
239         return ret;
240 }
241
242 /**
243  *      set_irq_wake - control irq power management wakeup
244  *      @irq:   interrupt to control
245  *      @on:    enable/disable power management wakeup
246  *
247  *      Enable/disable power management wakeup mode, which is
248  *      disabled by default.  Enables and disables must match,
249  *      just as they match for non-wakeup mode support.
250  *
251  *      Wakeup mode lets this IRQ wake the system from sleep
252  *      states like "suspend to RAM".
253  */
254 int set_irq_wake(unsigned int irq, unsigned int on)
255 {
256         struct irq_desc *desc = irq_to_desc(irq);
257         unsigned long flags;
258         int ret = 0;
259
260         /* wakeup-capable irqs can be shared between drivers that
261          * don't need to have the same sleep mode behaviors.
262          */
263         spin_lock_irqsave(&desc->lock, flags);
264         if (on) {
265                 if (desc->wake_depth++ == 0) {
266                         ret = set_irq_wake_real(irq, on);
267                         if (ret)
268                                 desc->wake_depth = 0;
269                         else
270                                 desc->status |= IRQ_WAKEUP;
271                 }
272         } else {
273                 if (desc->wake_depth == 0) {
274                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
275                 } else if (--desc->wake_depth == 0) {
276                         ret = set_irq_wake_real(irq, on);
277                         if (ret)
278                                 desc->wake_depth = 1;
279                         else
280                                 desc->status &= ~IRQ_WAKEUP;
281                 }
282         }
283
284         spin_unlock_irqrestore(&desc->lock, flags);
285         return ret;
286 }
287 EXPORT_SYMBOL(set_irq_wake);
288
289 /*
290  * Internal function that tells the architecture code whether a
291  * particular irq has been exclusively allocated or is available
292  * for driver use.
293  */
294 int can_request_irq(unsigned int irq, unsigned long irqflags)
295 {
296         struct irq_desc *desc;
297         struct irqaction *action;
298
299         desc = irq_to_desc(irq);
300         if (!desc)
301                 return 0;
302
303         if (desc->status & IRQ_NOREQUEST)
304                 return 0;
305
306         action = desc->action;
307         if (action)
308                 if (irqflags & action->flags & IRQF_SHARED)
309                         action = NULL;
310
311         return !action;
312 }
313
314 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
315 {
316         /*
317          * If the architecture still has not overriden
318          * the flow handler then zap the default. This
319          * should catch incorrect flow-type setting.
320          */
321         if (desc->handle_irq == &handle_bad_irq)
322                 desc->handle_irq = NULL;
323 }
324
325 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
326                 unsigned long flags)
327 {
328         int ret;
329         struct irq_chip *chip = desc->chip;
330
331         if (!chip || !chip->set_type) {
332                 /*
333                  * IRQF_TRIGGER_* but the PIC does not support multiple
334                  * flow-types?
335                  */
336                 pr_warning("No set_type function for IRQ %d (%s)\n", irq,
337                                 chip ? (chip->name ? : "unknown") : "unknown");
338                 return 0;
339         }
340
341         ret = chip->set_type(irq, flags & IRQF_TRIGGER_MASK);
342
343         if (ret)
344                 pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
345                                 (int)(flags & IRQF_TRIGGER_MASK),
346                                 irq, chip->set_type);
347         else {
348                 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
349                 desc->status &= ~IRQ_TYPE_SENSE_MASK;
350                 desc->status |= flags & IRQ_TYPE_SENSE_MASK;
351         }
352
353         return ret;
354 }
355
356 /*
357  * Internal function to register an irqaction - typically used to
358  * allocate special interrupts that are part of the architecture.
359  */
360 int setup_irq(unsigned int irq, struct irqaction *new)
361 {
362         struct irq_desc *desc;
363         struct irqaction *old, **p;
364         const char *old_name = NULL;
365         unsigned long flags;
366         int shared = 0;
367         int ret;
368
369         desc = irq_to_desc(irq);
370         if (!desc)
371                 return -EINVAL;
372
373         if (desc->chip == &no_irq_chip)
374                 return -ENOSYS;
375         /*
376          * Some drivers like serial.c use request_irq() heavily,
377          * so we have to be careful not to interfere with a
378          * running system.
379          */
380         if (new->flags & IRQF_SAMPLE_RANDOM) {
381                 /*
382                  * This function might sleep, we want to call it first,
383                  * outside of the atomic block.
384                  * Yes, this might clear the entropy pool if the wrong
385                  * driver is attempted to be loaded, without actually
386                  * installing a new handler, but is this really a problem,
387                  * only the sysadmin is able to do this.
388                  */
389                 rand_initialize_irq(irq);
390         }
391
392         /*
393          * The following block of code has to be executed atomically
394          */
395         spin_lock_irqsave(&desc->lock, flags);
396         p = &desc->action;
397         old = *p;
398         if (old) {
399                 /*
400                  * Can't share interrupts unless both agree to and are
401                  * the same type (level, edge, polarity). So both flag
402                  * fields must have IRQF_SHARED set and the bits which
403                  * set the trigger type must match.
404                  */
405                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
406                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
407                         old_name = old->name;
408                         goto mismatch;
409                 }
410
411 #if defined(CONFIG_IRQ_PER_CPU)
412                 /* All handlers must agree on per-cpuness */
413                 if ((old->flags & IRQF_PERCPU) !=
414                     (new->flags & IRQF_PERCPU))
415                         goto mismatch;
416 #endif
417
418                 /* add new interrupt at end of irq queue */
419                 do {
420                         p = &old->next;
421                         old = *p;
422                 } while (old);
423                 shared = 1;
424         }
425
426         if (!shared) {
427                 irq_chip_set_defaults(desc->chip);
428
429                 /* Setup the type (level, edge polarity) if configured: */
430                 if (new->flags & IRQF_TRIGGER_MASK) {
431                         ret = __irq_set_trigger(desc, irq, new->flags);
432
433                         if (ret) {
434                                 spin_unlock_irqrestore(&desc->lock, flags);
435                                 return ret;
436                         }
437                 } else
438                         compat_irq_chip_set_default_handler(desc);
439 #if defined(CONFIG_IRQ_PER_CPU)
440                 if (new->flags & IRQF_PERCPU)
441                         desc->status |= IRQ_PER_CPU;
442 #endif
443
444                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
445                                   IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
446
447                 if (!(desc->status & IRQ_NOAUTOEN)) {
448                         desc->depth = 0;
449                         desc->status &= ~IRQ_DISABLED;
450                         desc->chip->startup(irq);
451                 } else
452                         /* Undo nested disables: */
453                         desc->depth = 1;
454
455                 /* Set default affinity mask once everything is setup */
456                 irq_select_affinity(irq);
457
458         } else if ((new->flags & IRQF_TRIGGER_MASK)
459                         && (new->flags & IRQF_TRIGGER_MASK)
460                                 != (desc->status & IRQ_TYPE_SENSE_MASK)) {
461                 /* hope the handler works with the actual trigger mode... */
462                 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
463                                 irq, (int)(desc->status & IRQ_TYPE_SENSE_MASK),
464                                 (int)(new->flags & IRQF_TRIGGER_MASK));
465         }
466
467         *p = new;
468
469         /* Exclude IRQ from balancing */
470         if (new->flags & IRQF_NOBALANCING)
471                 desc->status |= IRQ_NO_BALANCING;
472
473         /* Reset broken irq detection when installing new handler */
474         desc->irq_count = 0;
475         desc->irqs_unhandled = 0;
476
477         /*
478          * Check whether we disabled the irq via the spurious handler
479          * before. Reenable it and give it another chance.
480          */
481         if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
482                 desc->status &= ~IRQ_SPURIOUS_DISABLED;
483                 __enable_irq(desc, irq);
484         }
485
486         spin_unlock_irqrestore(&desc->lock, flags);
487
488         new->irq = irq;
489         register_irq_proc(irq, desc);
490         new->dir = NULL;
491         register_handler_proc(irq, new);
492
493         return 0;
494
495 mismatch:
496 #ifdef CONFIG_DEBUG_SHIRQ
497         if (!(new->flags & IRQF_PROBE_SHARED)) {
498                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
499                 if (old_name)
500                         printk(KERN_ERR "current handler: %s\n", old_name);
501                 dump_stack();
502         }
503 #endif
504         spin_unlock_irqrestore(&desc->lock, flags);
505         return -EBUSY;
506 }
507
508 /**
509  *      free_irq - free an interrupt
510  *      @irq: Interrupt line to free
511  *      @dev_id: Device identity to free
512  *
513  *      Remove an interrupt handler. The handler is removed and if the
514  *      interrupt line is no longer in use by any driver it is disabled.
515  *      On a shared IRQ the caller must ensure the interrupt is disabled
516  *      on the card it drives before calling this function. The function
517  *      does not return until any executing interrupts for this IRQ
518  *      have completed.
519  *
520  *      This function must not be called from interrupt context.
521  */
522 void free_irq(unsigned int irq, void *dev_id)
523 {
524         struct irq_desc *desc;
525         struct irqaction **p;
526         unsigned long flags;
527
528         WARN_ON(in_interrupt());
529
530         desc = irq_to_desc(irq);
531         if (!desc)
532                 return;
533
534         spin_lock_irqsave(&desc->lock, flags);
535         p = &desc->action;
536         for (;;) {
537                 struct irqaction *action = *p;
538
539                 if (action) {
540                         struct irqaction **pp = p;
541
542                         p = &action->next;
543                         if (action->dev_id != dev_id)
544                                 continue;
545
546                         /* Found it - now remove it from the list of entries */
547                         *pp = action->next;
548
549                         /* Currently used only by UML, might disappear one day.*/
550 #ifdef CONFIG_IRQ_RELEASE_METHOD
551                         if (desc->chip->release)
552                                 desc->chip->release(irq, dev_id);
553 #endif
554
555                         if (!desc->action) {
556                                 desc->status |= IRQ_DISABLED;
557                                 if (desc->chip->shutdown)
558                                         desc->chip->shutdown(irq);
559                                 else
560                                         desc->chip->disable(irq);
561                         }
562                         spin_unlock_irqrestore(&desc->lock, flags);
563                         unregister_handler_proc(irq, action);
564
565                         /* Make sure it's not being used on another CPU */
566                         synchronize_irq(irq);
567 #ifdef CONFIG_DEBUG_SHIRQ
568                         /*
569                          * It's a shared IRQ -- the driver ought to be
570                          * prepared for it to happen even now it's
571                          * being freed, so let's make sure....  We do
572                          * this after actually deregistering it, to
573                          * make sure that a 'real' IRQ doesn't run in
574                          * parallel with our fake
575                          */
576                         if (action->flags & IRQF_SHARED) {
577                                 local_irq_save(flags);
578                                 action->handler(irq, dev_id);
579                                 local_irq_restore(flags);
580                         }
581 #endif
582                         kfree(action);
583                         return;
584                 }
585                 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
586 #ifdef CONFIG_DEBUG_SHIRQ
587                 dump_stack();
588 #endif
589                 spin_unlock_irqrestore(&desc->lock, flags);
590                 return;
591         }
592 }
593 EXPORT_SYMBOL(free_irq);
594
595 /**
596  *      request_irq - allocate an interrupt line
597  *      @irq: Interrupt line to allocate
598  *      @handler: Function to be called when the IRQ occurs
599  *      @irqflags: Interrupt type flags
600  *      @devname: An ascii name for the claiming device
601  *      @dev_id: A cookie passed back to the handler function
602  *
603  *      This call allocates interrupt resources and enables the
604  *      interrupt line and IRQ handling. From the point this
605  *      call is made your handler function may be invoked. Since
606  *      your handler function must clear any interrupt the board
607  *      raises, you must take care both to initialise your hardware
608  *      and to set up the interrupt handler in the right order.
609  *
610  *      Dev_id must be globally unique. Normally the address of the
611  *      device data structure is used as the cookie. Since the handler
612  *      receives this value it makes sense to use it.
613  *
614  *      If your interrupt is shared you must pass a non NULL dev_id
615  *      as this is required when freeing the interrupt.
616  *
617  *      Flags:
618  *
619  *      IRQF_SHARED             Interrupt is shared
620  *      IRQF_DISABLED   Disable local interrupts while processing
621  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
622  *      IRQF_TRIGGER_*          Specify active edge(s) or level
623  *
624  */
625 int request_irq(unsigned int irq, irq_handler_t handler,
626                 unsigned long irqflags, const char *devname, void *dev_id)
627 {
628         struct irqaction *action;
629         int retval;
630         struct irq_desc *desc;
631
632 #ifdef CONFIG_LOCKDEP
633         /*
634          * Lockdep wants atomic interrupt handlers:
635          */
636         irqflags |= IRQF_DISABLED;
637 #endif
638         /*
639          * Sanity-check: shared interrupts must pass in a real dev-ID,
640          * otherwise we'll have trouble later trying to figure out
641          * which interrupt is which (messes up the interrupt freeing
642          * logic etc).
643          */
644         if ((irqflags & IRQF_SHARED) && !dev_id)
645                 return -EINVAL;
646
647         desc = irq_to_desc(irq);
648         if (!desc)
649                 return -EINVAL;
650
651         if (desc->status & IRQ_NOREQUEST)
652                 return -EINVAL;
653         if (!handler)
654                 return -EINVAL;
655
656         action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
657         if (!action)
658                 return -ENOMEM;
659
660         action->handler = handler;
661         action->flags = irqflags;
662         cpus_clear(action->mask);
663         action->name = devname;
664         action->next = NULL;
665         action->dev_id = dev_id;
666
667         retval = setup_irq(irq, action);
668         if (retval)
669                 kfree(action);
670
671 #ifdef CONFIG_DEBUG_SHIRQ
672         if (irqflags & IRQF_SHARED) {
673                 /*
674                  * It's a shared IRQ -- the driver ought to be prepared for it
675                  * to happen immediately, so let's make sure....
676                  * We disable the irq to make sure that a 'real' IRQ doesn't
677                  * run in parallel with our fake.
678                  */
679                 unsigned long flags;
680
681                 disable_irq(irq);
682                 local_irq_save(flags);
683
684                 handler(irq, dev_id);
685
686                 local_irq_restore(flags);
687                 enable_irq(irq);
688         }
689 #endif
690         return retval;
691 }
692 EXPORT_SYMBOL(request_irq);