Merge branch 'linus' into x86/x2apic
[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                 printk(KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
188                 WARN_ON(1);
189                 break;
190         case 1: {
191                 unsigned int status = desc->status & ~IRQ_DISABLED;
192
193                 /* Prevent probing on this irq: */
194                 desc->status = status | IRQ_NOPROBE;
195                 check_irq_resend(desc, irq);
196                 /* fall-through */
197         }
198         default:
199                 desc->depth--;
200         }
201 }
202
203 /**
204  *      enable_irq - enable handling of an irq
205  *      @irq: Interrupt to enable
206  *
207  *      Undoes the effect of one call to disable_irq().  If this
208  *      matches the last disable, processing of interrupts on this
209  *      IRQ line is re-enabled.
210  *
211  *      This function may be called from IRQ context.
212  */
213 void enable_irq(unsigned int irq)
214 {
215         struct irq_desc *desc = irq_desc + irq;
216         unsigned long flags;
217
218         if (irq >= NR_IRQS)
219                 return;
220
221         spin_lock_irqsave(&desc->lock, flags);
222         __enable_irq(desc, irq);
223         spin_unlock_irqrestore(&desc->lock, flags);
224 }
225 EXPORT_SYMBOL(enable_irq);
226
227 int set_irq_wake_real(unsigned int irq, unsigned int on)
228 {
229         struct irq_desc *desc = irq_desc + irq;
230         int ret = -ENXIO;
231
232         if (desc->chip->set_wake)
233                 ret = desc->chip->set_wake(irq, on);
234
235         return ret;
236 }
237
238 /**
239  *      set_irq_wake - control irq power management wakeup
240  *      @irq:   interrupt to control
241  *      @on:    enable/disable power management wakeup
242  *
243  *      Enable/disable power management wakeup mode, which is
244  *      disabled by default.  Enables and disables must match,
245  *      just as they match for non-wakeup mode support.
246  *
247  *      Wakeup mode lets this IRQ wake the system from sleep
248  *      states like "suspend to RAM".
249  */
250 int set_irq_wake(unsigned int irq, unsigned int on)
251 {
252         struct irq_desc *desc = irq_desc + irq;
253         unsigned long flags;
254         int ret = 0;
255
256         /* wakeup-capable irqs can be shared between drivers that
257          * don't need to have the same sleep mode behaviors.
258          */
259         spin_lock_irqsave(&desc->lock, flags);
260         if (on) {
261                 if (desc->wake_depth++ == 0) {
262                         ret = set_irq_wake_real(irq, on);
263                         if (ret)
264                                 desc->wake_depth = 0;
265                         else
266                                 desc->status |= IRQ_WAKEUP;
267                 }
268         } else {
269                 if (desc->wake_depth == 0) {
270                         printk(KERN_WARNING "Unbalanced IRQ %d "
271                                         "wake disable\n", irq);
272                         WARN_ON(1);
273                 } else if (--desc->wake_depth == 0) {
274                         ret = set_irq_wake_real(irq, on);
275                         if (ret)
276                                 desc->wake_depth = 1;
277                         else
278                                 desc->status &= ~IRQ_WAKEUP;
279                 }
280         }
281
282         spin_unlock_irqrestore(&desc->lock, flags);
283         return ret;
284 }
285 EXPORT_SYMBOL(set_irq_wake);
286
287 /*
288  * Internal function that tells the architecture code whether a
289  * particular irq has been exclusively allocated or is available
290  * for driver use.
291  */
292 int can_request_irq(unsigned int irq, unsigned long irqflags)
293 {
294         struct irqaction *action;
295
296         if (irq >= NR_IRQS || irq_desc[irq].status & IRQ_NOREQUEST)
297                 return 0;
298
299         action = irq_desc[irq].action;
300         if (action)
301                 if (irqflags & action->flags & IRQF_SHARED)
302                         action = NULL;
303
304         return !action;
305 }
306
307 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
308 {
309         /*
310          * If the architecture still has not overriden
311          * the flow handler then zap the default. This
312          * should catch incorrect flow-type setting.
313          */
314         if (desc->handle_irq == &handle_bad_irq)
315                 desc->handle_irq = NULL;
316 }
317
318 static int __irq_set_trigger(struct irq_chip *chip, unsigned int irq,
319                 unsigned long flags)
320 {
321         int ret;
322
323         if (!chip || !chip->set_type) {
324                 /*
325                  * IRQF_TRIGGER_* but the PIC does not support multiple
326                  * flow-types?
327                  */
328                 pr_warning("No set_type function for IRQ %d (%s)\n", irq,
329                                 chip ? (chip->name ? : "unknown") : "unknown");
330                 return 0;
331         }
332
333         ret = chip->set_type(irq, flags & IRQF_TRIGGER_MASK);
334
335         if (ret)
336                 pr_err("setting flow type for irq %u failed (%pF)\n",
337                                 irq, chip->set_type);
338
339         return ret;
340 }
341
342 /*
343  * Internal function to register an irqaction - typically used to
344  * allocate special interrupts that are part of the architecture.
345  */
346 int setup_irq(unsigned int irq, struct irqaction *new)
347 {
348         struct irq_desc *desc = irq_desc + irq;
349         struct irqaction *old, **p;
350         const char *old_name = NULL;
351         unsigned long flags;
352         int shared = 0;
353         int ret;
354
355         if (irq >= NR_IRQS)
356                 return -EINVAL;
357
358         if (desc->chip == &no_irq_chip)
359                 return -ENOSYS;
360         /*
361          * Some drivers like serial.c use request_irq() heavily,
362          * so we have to be careful not to interfere with a
363          * running system.
364          */
365         if (new->flags & IRQF_SAMPLE_RANDOM) {
366                 /*
367                  * This function might sleep, we want to call it first,
368                  * outside of the atomic block.
369                  * Yes, this might clear the entropy pool if the wrong
370                  * driver is attempted to be loaded, without actually
371                  * installing a new handler, but is this really a problem,
372                  * only the sysadmin is able to do this.
373                  */
374                 rand_initialize_irq(irq);
375         }
376
377         /*
378          * The following block of code has to be executed atomically
379          */
380         spin_lock_irqsave(&desc->lock, flags);
381         p = &desc->action;
382         old = *p;
383         if (old) {
384                 /*
385                  * Can't share interrupts unless both agree to and are
386                  * the same type (level, edge, polarity). So both flag
387                  * fields must have IRQF_SHARED set and the bits which
388                  * set the trigger type must match.
389                  */
390                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
391                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
392                         old_name = old->name;
393                         goto mismatch;
394                 }
395
396 #if defined(CONFIG_IRQ_PER_CPU)
397                 /* All handlers must agree on per-cpuness */
398                 if ((old->flags & IRQF_PERCPU) !=
399                     (new->flags & IRQF_PERCPU))
400                         goto mismatch;
401 #endif
402
403                 /* add new interrupt at end of irq queue */
404                 do {
405                         p = &old->next;
406                         old = *p;
407                 } while (old);
408                 shared = 1;
409         }
410
411         if (!shared) {
412                 irq_chip_set_defaults(desc->chip);
413
414                 /* Setup the type (level, edge polarity) if configured: */
415                 if (new->flags & IRQF_TRIGGER_MASK) {
416                         ret = __irq_set_trigger(desc->chip, irq, new->flags);
417
418                         if (ret) {
419                                 spin_unlock_irqrestore(&desc->lock, flags);
420                                 return ret;
421                         }
422                 } else
423                         compat_irq_chip_set_default_handler(desc);
424 #if defined(CONFIG_IRQ_PER_CPU)
425                 if (new->flags & IRQF_PERCPU)
426                         desc->status |= IRQ_PER_CPU;
427 #endif
428
429                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
430                                   IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
431
432                 if (!(desc->status & IRQ_NOAUTOEN)) {
433                         desc->depth = 0;
434                         desc->status &= ~IRQ_DISABLED;
435                         if (desc->chip->startup)
436                                 desc->chip->startup(irq);
437                         else
438                                 desc->chip->enable(irq);
439                 } else
440                         /* Undo nested disables: */
441                         desc->depth = 1;
442
443                 /* Set default affinity mask once everything is setup */
444                 irq_select_affinity(irq);
445         }
446
447         *p = new;
448
449         /* Exclude IRQ from balancing */
450         if (new->flags & IRQF_NOBALANCING)
451                 desc->status |= IRQ_NO_BALANCING;
452
453         /* Reset broken irq detection when installing new handler */
454         desc->irq_count = 0;
455         desc->irqs_unhandled = 0;
456
457         /*
458          * Check whether we disabled the irq via the spurious handler
459          * before. Reenable it and give it another chance.
460          */
461         if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
462                 desc->status &= ~IRQ_SPURIOUS_DISABLED;
463                 __enable_irq(desc, irq);
464         }
465
466         spin_unlock_irqrestore(&desc->lock, flags);
467
468         new->irq = irq;
469         register_irq_proc(irq);
470         new->dir = NULL;
471         register_handler_proc(irq, new);
472
473         return 0;
474
475 mismatch:
476 #ifdef CONFIG_DEBUG_SHIRQ
477         if (!(new->flags & IRQF_PROBE_SHARED)) {
478                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
479                 if (old_name)
480                         printk(KERN_ERR "current handler: %s\n", old_name);
481                 dump_stack();
482         }
483 #endif
484         spin_unlock_irqrestore(&desc->lock, flags);
485         return -EBUSY;
486 }
487
488 /**
489  *      free_irq - free an interrupt
490  *      @irq: Interrupt line to free
491  *      @dev_id: Device identity to free
492  *
493  *      Remove an interrupt handler. The handler is removed and if the
494  *      interrupt line is no longer in use by any driver it is disabled.
495  *      On a shared IRQ the caller must ensure the interrupt is disabled
496  *      on the card it drives before calling this function. The function
497  *      does not return until any executing interrupts for this IRQ
498  *      have completed.
499  *
500  *      This function must not be called from interrupt context.
501  */
502 void free_irq(unsigned int irq, void *dev_id)
503 {
504         struct irq_desc *desc;
505         struct irqaction **p;
506         unsigned long flags;
507
508         WARN_ON(in_interrupt());
509         if (irq >= NR_IRQS)
510                 return;
511
512         desc = irq_desc + irq;
513         spin_lock_irqsave(&desc->lock, flags);
514         p = &desc->action;
515         for (;;) {
516                 struct irqaction *action = *p;
517
518                 if (action) {
519                         struct irqaction **pp = p;
520
521                         p = &action->next;
522                         if (action->dev_id != dev_id)
523                                 continue;
524
525                         /* Found it - now remove it from the list of entries */
526                         *pp = action->next;
527
528                         /* Currently used only by UML, might disappear one day.*/
529 #ifdef CONFIG_IRQ_RELEASE_METHOD
530                         if (desc->chip->release)
531                                 desc->chip->release(irq, dev_id);
532 #endif
533
534                         if (!desc->action) {
535                                 desc->status |= IRQ_DISABLED;
536                                 if (desc->chip->shutdown)
537                                         desc->chip->shutdown(irq);
538                                 else
539                                         desc->chip->disable(irq);
540                         }
541                         spin_unlock_irqrestore(&desc->lock, flags);
542                         unregister_handler_proc(irq, action);
543
544                         /* Make sure it's not being used on another CPU */
545                         synchronize_irq(irq);
546 #ifdef CONFIG_DEBUG_SHIRQ
547                         /*
548                          * It's a shared IRQ -- the driver ought to be
549                          * prepared for it to happen even now it's
550                          * being freed, so let's make sure....  We do
551                          * this after actually deregistering it, to
552                          * make sure that a 'real' IRQ doesn't run in
553                          * parallel with our fake
554                          */
555                         if (action->flags & IRQF_SHARED) {
556                                 local_irq_save(flags);
557                                 action->handler(irq, dev_id);
558                                 local_irq_restore(flags);
559                         }
560 #endif
561                         kfree(action);
562                         return;
563                 }
564                 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
565 #ifdef CONFIG_DEBUG_SHIRQ
566                 dump_stack();
567 #endif
568                 spin_unlock_irqrestore(&desc->lock, flags);
569                 return;
570         }
571 }
572 EXPORT_SYMBOL(free_irq);
573
574 /**
575  *      request_irq - allocate an interrupt line
576  *      @irq: Interrupt line to allocate
577  *      @handler: Function to be called when the IRQ occurs
578  *      @irqflags: Interrupt type flags
579  *      @devname: An ascii name for the claiming device
580  *      @dev_id: A cookie passed back to the handler function
581  *
582  *      This call allocates interrupt resources and enables the
583  *      interrupt line and IRQ handling. From the point this
584  *      call is made your handler function may be invoked. Since
585  *      your handler function must clear any interrupt the board
586  *      raises, you must take care both to initialise your hardware
587  *      and to set up the interrupt handler in the right order.
588  *
589  *      Dev_id must be globally unique. Normally the address of the
590  *      device data structure is used as the cookie. Since the handler
591  *      receives this value it makes sense to use it.
592  *
593  *      If your interrupt is shared you must pass a non NULL dev_id
594  *      as this is required when freeing the interrupt.
595  *
596  *      Flags:
597  *
598  *      IRQF_SHARED             Interrupt is shared
599  *      IRQF_DISABLED   Disable local interrupts while processing
600  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
601  *
602  */
603 int request_irq(unsigned int irq, irq_handler_t handler,
604                 unsigned long irqflags, const char *devname, void *dev_id)
605 {
606         struct irqaction *action;
607         int retval;
608
609 #ifdef CONFIG_LOCKDEP
610         /*
611          * Lockdep wants atomic interrupt handlers:
612          */
613         irqflags |= IRQF_DISABLED;
614 #endif
615         /*
616          * Sanity-check: shared interrupts must pass in a real dev-ID,
617          * otherwise we'll have trouble later trying to figure out
618          * which interrupt is which (messes up the interrupt freeing
619          * logic etc).
620          */
621         if ((irqflags & IRQF_SHARED) && !dev_id)
622                 return -EINVAL;
623         if (irq >= NR_IRQS)
624                 return -EINVAL;
625         if (irq_desc[irq].status & IRQ_NOREQUEST)
626                 return -EINVAL;
627         if (!handler)
628                 return -EINVAL;
629
630         action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
631         if (!action)
632                 return -ENOMEM;
633
634         action->handler = handler;
635         action->flags = irqflags;
636         cpus_clear(action->mask);
637         action->name = devname;
638         action->next = NULL;
639         action->dev_id = dev_id;
640
641 #ifdef CONFIG_DEBUG_SHIRQ
642         if (irqflags & IRQF_SHARED) {
643                 /*
644                  * It's a shared IRQ -- the driver ought to be prepared for it
645                  * to happen immediately, so let's make sure....
646                  * We do this before actually registering it, to make sure that
647                  * a 'real' IRQ doesn't run in parallel with our fake
648                  */
649                 unsigned long flags;
650
651                 local_irq_save(flags);
652                 handler(irq, dev_id);
653                 local_irq_restore(flags);
654         }
655 #endif
656
657         retval = setup_irq(irq, action);
658         if (retval)
659                 kfree(action);
660
661         return retval;
662 }
663 EXPORT_SYMBOL(request_irq);