Merge commit 'v2.6.27-rc1' into x86/core
[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 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 static int __irq_set_trigger(struct irq_chip *chip, unsigned int irq,
316                 unsigned long flags)
317 {
318         int ret;
319
320         if (!chip || !chip->set_type) {
321                 /*
322                  * IRQF_TRIGGER_* but the PIC does not support multiple
323                  * flow-types?
324                  */
325                 pr_warning("No set_type function for IRQ %d (%s)\n", irq,
326                                 chip ? (chip->name ? : "unknown") : "unknown");
327                 return 0;
328         }
329
330         ret = chip->set_type(irq, flags & IRQF_TRIGGER_MASK);
331
332         if (ret)
333                 pr_err("setting flow type for irq %u failed (%pF)\n",
334                                 irq, chip->set_type);
335
336         return ret;
337 }
338
339 /*
340  * Internal function to register an irqaction - typically used to
341  * allocate special interrupts that are part of the architecture.
342  */
343 int setup_irq(unsigned int irq, struct irqaction *new)
344 {
345         struct irq_desc *desc = irq_desc + irq;
346         struct irqaction *old, **p;
347         const char *old_name = NULL;
348         unsigned long flags;
349         int shared = 0;
350         int ret;
351
352         if (irq >= NR_IRQS)
353                 return -EINVAL;
354
355         if (desc->chip == &no_irq_chip)
356                 return -ENOSYS;
357         /*
358          * Some drivers like serial.c use request_irq() heavily,
359          * so we have to be careful not to interfere with a
360          * running system.
361          */
362         if (new->flags & IRQF_SAMPLE_RANDOM) {
363                 /*
364                  * This function might sleep, we want to call it first,
365                  * outside of the atomic block.
366                  * Yes, this might clear the entropy pool if the wrong
367                  * driver is attempted to be loaded, without actually
368                  * installing a new handler, but is this really a problem,
369                  * only the sysadmin is able to do this.
370                  */
371                 rand_initialize_irq(irq);
372         }
373
374         /*
375          * The following block of code has to be executed atomically
376          */
377         spin_lock_irqsave(&desc->lock, flags);
378         p = &desc->action;
379         old = *p;
380         if (old) {
381                 /*
382                  * Can't share interrupts unless both agree to and are
383                  * the same type (level, edge, polarity). So both flag
384                  * fields must have IRQF_SHARED set and the bits which
385                  * set the trigger type must match.
386                  */
387                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
388                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
389                         old_name = old->name;
390                         goto mismatch;
391                 }
392
393 #if defined(CONFIG_IRQ_PER_CPU)
394                 /* All handlers must agree on per-cpuness */
395                 if ((old->flags & IRQF_PERCPU) !=
396                     (new->flags & IRQF_PERCPU))
397                         goto mismatch;
398 #endif
399
400                 /* add new interrupt at end of irq queue */
401                 do {
402                         p = &old->next;
403                         old = *p;
404                 } while (old);
405                 shared = 1;
406         }
407
408         if (!shared) {
409                 irq_chip_set_defaults(desc->chip);
410
411                 /* Setup the type (level, edge polarity) if configured: */
412                 if (new->flags & IRQF_TRIGGER_MASK) {
413                         ret = __irq_set_trigger(desc->chip, irq, new->flags);
414
415                         if (ret) {
416                                 spin_unlock_irqrestore(&desc->lock, flags);
417                                 return ret;
418                         }
419                 } else
420                         compat_irq_chip_set_default_handler(desc);
421 #if defined(CONFIG_IRQ_PER_CPU)
422                 if (new->flags & IRQF_PERCPU)
423                         desc->status |= IRQ_PER_CPU;
424 #endif
425
426                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
427                                   IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
428
429                 if (!(desc->status & IRQ_NOAUTOEN)) {
430                         desc->depth = 0;
431                         desc->status &= ~IRQ_DISABLED;
432                         if (desc->chip->startup)
433                                 desc->chip->startup(irq);
434                         else
435                                 desc->chip->enable(irq);
436                 } else
437                         /* Undo nested disables: */
438                         desc->depth = 1;
439
440                 /* Set default affinity mask once everything is setup */
441                 irq_select_affinity(irq);
442         }
443
444         *p = new;
445
446         /* Exclude IRQ from balancing */
447         if (new->flags & IRQF_NOBALANCING)
448                 desc->status |= IRQ_NO_BALANCING;
449
450         /* Reset broken irq detection when installing new handler */
451         desc->irq_count = 0;
452         desc->irqs_unhandled = 0;
453
454         /*
455          * Check whether we disabled the irq via the spurious handler
456          * before. Reenable it and give it another chance.
457          */
458         if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
459                 desc->status &= ~IRQ_SPURIOUS_DISABLED;
460                 __enable_irq(desc, irq);
461         }
462
463         spin_unlock_irqrestore(&desc->lock, flags);
464
465         new->irq = irq;
466         register_irq_proc(irq);
467         new->dir = NULL;
468         register_handler_proc(irq, new);
469
470         return 0;
471
472 mismatch:
473 #ifdef CONFIG_DEBUG_SHIRQ
474         if (!(new->flags & IRQF_PROBE_SHARED)) {
475                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
476                 if (old_name)
477                         printk(KERN_ERR "current handler: %s\n", old_name);
478                 dump_stack();
479         }
480 #endif
481         spin_unlock_irqrestore(&desc->lock, flags);
482         return -EBUSY;
483 }
484
485 /**
486  *      free_irq - free an interrupt
487  *      @irq: Interrupt line to free
488  *      @dev_id: Device identity to free
489  *
490  *      Remove an interrupt handler. The handler is removed and if the
491  *      interrupt line is no longer in use by any driver it is disabled.
492  *      On a shared IRQ the caller must ensure the interrupt is disabled
493  *      on the card it drives before calling this function. The function
494  *      does not return until any executing interrupts for this IRQ
495  *      have completed.
496  *
497  *      This function must not be called from interrupt context.
498  */
499 void free_irq(unsigned int irq, void *dev_id)
500 {
501         struct irq_desc *desc;
502         struct irqaction **p;
503         unsigned long flags;
504
505         WARN_ON(in_interrupt());
506         if (irq >= NR_IRQS)
507                 return;
508
509         desc = irq_desc + irq;
510         spin_lock_irqsave(&desc->lock, flags);
511         p = &desc->action;
512         for (;;) {
513                 struct irqaction *action = *p;
514
515                 if (action) {
516                         struct irqaction **pp = p;
517
518                         p = &action->next;
519                         if (action->dev_id != dev_id)
520                                 continue;
521
522                         /* Found it - now remove it from the list of entries */
523                         *pp = action->next;
524
525                         /* Currently used only by UML, might disappear one day.*/
526 #ifdef CONFIG_IRQ_RELEASE_METHOD
527                         if (desc->chip->release)
528                                 desc->chip->release(irq, dev_id);
529 #endif
530
531                         if (!desc->action) {
532                                 desc->status |= IRQ_DISABLED;
533                                 if (desc->chip->shutdown)
534                                         desc->chip->shutdown(irq);
535                                 else
536                                         desc->chip->disable(irq);
537                         }
538                         spin_unlock_irqrestore(&desc->lock, flags);
539                         unregister_handler_proc(irq, action);
540
541                         /* Make sure it's not being used on another CPU */
542                         synchronize_irq(irq);
543 #ifdef CONFIG_DEBUG_SHIRQ
544                         /*
545                          * It's a shared IRQ -- the driver ought to be
546                          * prepared for it to happen even now it's
547                          * being freed, so let's make sure....  We do
548                          * this after actually deregistering it, to
549                          * make sure that a 'real' IRQ doesn't run in
550                          * parallel with our fake
551                          */
552                         if (action->flags & IRQF_SHARED) {
553                                 local_irq_save(flags);
554                                 action->handler(irq, dev_id);
555                                 local_irq_restore(flags);
556                         }
557 #endif
558                         kfree(action);
559                         return;
560                 }
561                 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
562 #ifdef CONFIG_DEBUG_SHIRQ
563                 dump_stack();
564 #endif
565                 spin_unlock_irqrestore(&desc->lock, flags);
566                 return;
567         }
568 }
569 EXPORT_SYMBOL(free_irq);
570
571 /**
572  *      request_irq - allocate an interrupt line
573  *      @irq: Interrupt line to allocate
574  *      @handler: Function to be called when the IRQ occurs
575  *      @irqflags: Interrupt type flags
576  *      @devname: An ascii name for the claiming device
577  *      @dev_id: A cookie passed back to the handler function
578  *
579  *      This call allocates interrupt resources and enables the
580  *      interrupt line and IRQ handling. From the point this
581  *      call is made your handler function may be invoked. Since
582  *      your handler function must clear any interrupt the board
583  *      raises, you must take care both to initialise your hardware
584  *      and to set up the interrupt handler in the right order.
585  *
586  *      Dev_id must be globally unique. Normally the address of the
587  *      device data structure is used as the cookie. Since the handler
588  *      receives this value it makes sense to use it.
589  *
590  *      If your interrupt is shared you must pass a non NULL dev_id
591  *      as this is required when freeing the interrupt.
592  *
593  *      Flags:
594  *
595  *      IRQF_SHARED             Interrupt is shared
596  *      IRQF_DISABLED   Disable local interrupts while processing
597  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
598  *
599  */
600 int request_irq(unsigned int irq, irq_handler_t handler,
601                 unsigned long irqflags, const char *devname, void *dev_id)
602 {
603         struct irqaction *action;
604         int retval;
605
606 #ifdef CONFIG_LOCKDEP
607         /*
608          * Lockdep wants atomic interrupt handlers:
609          */
610         irqflags |= IRQF_DISABLED;
611 #endif
612         /*
613          * Sanity-check: shared interrupts must pass in a real dev-ID,
614          * otherwise we'll have trouble later trying to figure out
615          * which interrupt is which (messes up the interrupt freeing
616          * logic etc).
617          */
618         if ((irqflags & IRQF_SHARED) && !dev_id)
619                 return -EINVAL;
620         if (irq >= NR_IRQS)
621                 return -EINVAL;
622         if (irq_desc[irq].status & IRQ_NOREQUEST)
623                 return -EINVAL;
624         if (!handler)
625                 return -EINVAL;
626
627         action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
628         if (!action)
629                 return -ENOMEM;
630
631         action->handler = handler;
632         action->flags = irqflags;
633         cpus_clear(action->mask);
634         action->name = devname;
635         action->next = NULL;
636         action->dev_id = dev_id;
637
638 #ifdef CONFIG_DEBUG_SHIRQ
639         if (irqflags & IRQF_SHARED) {
640                 /*
641                  * It's a shared IRQ -- the driver ought to be prepared for it
642                  * to happen immediately, so let's make sure....
643                  * We do this before actually registering it, to make sure that
644                  * a 'real' IRQ doesn't run in parallel with our fake
645                  */
646                 unsigned long flags;
647
648                 local_irq_save(flags);
649                 handler(irq, dev_id);
650                 local_irq_restore(flags);
651         }
652 #endif
653
654         retval = setup_irq(irq, action);
655         if (retval)
656                 kfree(action);
657
658         return retval;
659 }
660 EXPORT_SYMBOL(request_irq);