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