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