Merge branch 'pci-for-jesse' of git://git.kernel.org/pub/scm/linux/kernel/git/tip...
[linux-2.6] / 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         set_pending_irq(irq, cpumask);
93 #else
94         desc->affinity = cpumask;
95         desc->chip->set_affinity(irq, cpumask);
96 #endif
97         return 0;
98 }
99
100 #ifndef CONFIG_AUTO_IRQ_AFFINITY
101 /*
102  * Generic version of the affinity autoselector.
103  */
104 int irq_select_affinity(unsigned int irq)
105 {
106         cpumask_t mask;
107
108         if (!irq_can_set_affinity(irq))
109                 return 0;
110
111         cpus_and(mask, cpu_online_map, irq_default_affinity);
112
113         irq_desc[irq].affinity = mask;
114         irq_desc[irq].chip->set_affinity(irq, mask);
115
116         set_balance_irq_affinity(irq, mask);
117         return 0;
118 }
119 #endif
120
121 #endif
122
123 /**
124  *      disable_irq_nosync - disable an irq without waiting
125  *      @irq: Interrupt to disable
126  *
127  *      Disable the selected interrupt line.  Disables and Enables are
128  *      nested.
129  *      Unlike disable_irq(), this function does not ensure existing
130  *      instances of the IRQ handler have completed before returning.
131  *
132  *      This function may be called from IRQ context.
133  */
134 void disable_irq_nosync(unsigned int irq)
135 {
136         struct irq_desc *desc = irq_desc + irq;
137         unsigned long flags;
138
139         if (irq >= NR_IRQS)
140                 return;
141
142         spin_lock_irqsave(&desc->lock, flags);
143         if (!desc->depth++) {
144                 desc->status |= IRQ_DISABLED;
145                 desc->chip->disable(irq);
146         }
147         spin_unlock_irqrestore(&desc->lock, flags);
148 }
149 EXPORT_SYMBOL(disable_irq_nosync);
150
151 /**
152  *      disable_irq - disable an irq and wait for completion
153  *      @irq: Interrupt to disable
154  *
155  *      Disable the selected interrupt line.  Enables and Disables are
156  *      nested.
157  *      This function waits for any pending IRQ handlers for this interrupt
158  *      to complete before returning. If you use this function while
159  *      holding a resource the IRQ handler may need you will deadlock.
160  *
161  *      This function may be called - with care - from IRQ context.
162  */
163 void disable_irq(unsigned int irq)
164 {
165         struct irq_desc *desc = irq_desc + irq;
166
167         if (irq >= NR_IRQS)
168                 return;
169
170         disable_irq_nosync(irq);
171         if (desc->action)
172                 synchronize_irq(irq);
173 }
174 EXPORT_SYMBOL(disable_irq);
175
176 static void __enable_irq(struct irq_desc *desc, unsigned int irq)
177 {
178         switch (desc->depth) {
179         case 0:
180                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
181                 break;
182         case 1: {
183                 unsigned int status = desc->status & ~IRQ_DISABLED;
184
185                 /* Prevent probing on this irq: */
186                 desc->status = status | IRQ_NOPROBE;
187                 check_irq_resend(desc, irq);
188                 /* fall-through */
189         }
190         default:
191                 desc->depth--;
192         }
193 }
194
195 /**
196  *      enable_irq - enable handling of an irq
197  *      @irq: Interrupt to enable
198  *
199  *      Undoes the effect of one call to disable_irq().  If this
200  *      matches the last disable, processing of interrupts on this
201  *      IRQ line is re-enabled.
202  *
203  *      This function may be called from IRQ context.
204  */
205 void enable_irq(unsigned int irq)
206 {
207         struct irq_desc *desc = irq_desc + irq;
208         unsigned long flags;
209
210         if (irq >= NR_IRQS)
211                 return;
212
213         spin_lock_irqsave(&desc->lock, flags);
214         __enable_irq(desc, irq);
215         spin_unlock_irqrestore(&desc->lock, flags);
216 }
217 EXPORT_SYMBOL(enable_irq);
218
219 int set_irq_wake_real(unsigned int irq, unsigned int on)
220 {
221         struct irq_desc *desc = irq_desc + irq;
222         int ret = -ENXIO;
223
224         if (desc->chip->set_wake)
225                 ret = desc->chip->set_wake(irq, on);
226
227         return ret;
228 }
229
230 /**
231  *      set_irq_wake - control irq power management wakeup
232  *      @irq:   interrupt to control
233  *      @on:    enable/disable power management wakeup
234  *
235  *      Enable/disable power management wakeup mode, which is
236  *      disabled by default.  Enables and disables must match,
237  *      just as they match for non-wakeup mode support.
238  *
239  *      Wakeup mode lets this IRQ wake the system from sleep
240  *      states like "suspend to RAM".
241  */
242 int set_irq_wake(unsigned int irq, unsigned int on)
243 {
244         struct irq_desc *desc = irq_desc + irq;
245         unsigned long flags;
246         int ret = 0;
247
248         /* wakeup-capable irqs can be shared between drivers that
249          * don't need to have the same sleep mode behaviors.
250          */
251         spin_lock_irqsave(&desc->lock, flags);
252         if (on) {
253                 if (desc->wake_depth++ == 0) {
254                         ret = set_irq_wake_real(irq, on);
255                         if (ret)
256                                 desc->wake_depth = 0;
257                         else
258                                 desc->status |= IRQ_WAKEUP;
259                 }
260         } else {
261                 if (desc->wake_depth == 0) {
262                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
263                 } else if (--desc->wake_depth == 0) {
264                         ret = set_irq_wake_real(irq, on);
265                         if (ret)
266                                 desc->wake_depth = 1;
267                         else
268                                 desc->status &= ~IRQ_WAKEUP;
269                 }
270         }
271
272         spin_unlock_irqrestore(&desc->lock, flags);
273         return ret;
274 }
275 EXPORT_SYMBOL(set_irq_wake);
276
277 /*
278  * Internal function that tells the architecture code whether a
279  * particular irq has been exclusively allocated or is available
280  * for driver use.
281  */
282 int can_request_irq(unsigned int irq, unsigned long irqflags)
283 {
284         struct irqaction *action;
285
286         if (irq >= NR_IRQS || irq_desc[irq].status & IRQ_NOREQUEST)
287                 return 0;
288
289         action = irq_desc[irq].action;
290         if (action)
291                 if (irqflags & action->flags & IRQF_SHARED)
292                         action = NULL;
293
294         return !action;
295 }
296
297 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
298 {
299         /*
300          * If the architecture still has not overriden
301          * the flow handler then zap the default. This
302          * should catch incorrect flow-type setting.
303          */
304         if (desc->handle_irq == &handle_bad_irq)
305                 desc->handle_irq = NULL;
306 }
307
308 static int __irq_set_trigger(struct irq_chip *chip, unsigned int irq,
309                 unsigned long flags)
310 {
311         int ret;
312
313         if (!chip || !chip->set_type) {
314                 /*
315                  * IRQF_TRIGGER_* but the PIC does not support multiple
316                  * flow-types?
317                  */
318                 pr_warning("No set_type function for IRQ %d (%s)\n", irq,
319                                 chip ? (chip->name ? : "unknown") : "unknown");
320                 return 0;
321         }
322
323         ret = chip->set_type(irq, flags & IRQF_TRIGGER_MASK);
324
325         if (ret)
326                 pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
327                                 (int)(flags & IRQF_TRIGGER_MASK),
328                                 irq, chip->set_type);
329
330         return ret;
331 }
332
333 /*
334  * Internal function to register an irqaction - typically used to
335  * allocate special interrupts that are part of the architecture.
336  */
337 int setup_irq(unsigned int irq, struct irqaction *new)
338 {
339         struct irq_desc *desc = irq_desc + irq;
340         struct irqaction *old, **p;
341         const char *old_name = NULL;
342         unsigned long flags;
343         int shared = 0;
344         int ret;
345
346         if (irq >= NR_IRQS)
347                 return -EINVAL;
348
349         if (desc->chip == &no_irq_chip)
350                 return -ENOSYS;
351         /*
352          * Some drivers like serial.c use request_irq() heavily,
353          * so we have to be careful not to interfere with a
354          * running system.
355          */
356         if (new->flags & IRQF_SAMPLE_RANDOM) {
357                 /*
358                  * This function might sleep, we want to call it first,
359                  * outside of the atomic block.
360                  * Yes, this might clear the entropy pool if the wrong
361                  * driver is attempted to be loaded, without actually
362                  * installing a new handler, but is this really a problem,
363                  * only the sysadmin is able to do this.
364                  */
365                 rand_initialize_irq(irq);
366         }
367
368         /*
369          * The following block of code has to be executed atomically
370          */
371         spin_lock_irqsave(&desc->lock, flags);
372         p = &desc->action;
373         old = *p;
374         if (old) {
375                 /*
376                  * Can't share interrupts unless both agree to and are
377                  * the same type (level, edge, polarity). So both flag
378                  * fields must have IRQF_SHARED set and the bits which
379                  * set the trigger type must match.
380                  */
381                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
382                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
383                         old_name = old->name;
384                         goto mismatch;
385                 }
386
387 #if defined(CONFIG_IRQ_PER_CPU)
388                 /* All handlers must agree on per-cpuness */
389                 if ((old->flags & IRQF_PERCPU) !=
390                     (new->flags & IRQF_PERCPU))
391                         goto mismatch;
392 #endif
393
394                 /* add new interrupt at end of irq queue */
395                 do {
396                         p = &old->next;
397                         old = *p;
398                 } while (old);
399                 shared = 1;
400         }
401
402         if (!shared) {
403                 irq_chip_set_defaults(desc->chip);
404
405                 /* Setup the type (level, edge polarity) if configured: */
406                 if (new->flags & IRQF_TRIGGER_MASK) {
407                         ret = __irq_set_trigger(desc->chip, irq, new->flags);
408
409                         if (ret) {
410                                 spin_unlock_irqrestore(&desc->lock, flags);
411                                 return ret;
412                         }
413                 } else
414                         compat_irq_chip_set_default_handler(desc);
415 #if defined(CONFIG_IRQ_PER_CPU)
416                 if (new->flags & IRQF_PERCPU)
417                         desc->status |= IRQ_PER_CPU;
418 #endif
419
420                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
421                                   IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
422
423                 if (!(desc->status & IRQ_NOAUTOEN)) {
424                         desc->depth = 0;
425                         desc->status &= ~IRQ_DISABLED;
426                         if (desc->chip->startup)
427                                 desc->chip->startup(irq);
428                         else
429                                 desc->chip->enable(irq);
430                 } else
431                         /* Undo nested disables: */
432                         desc->depth = 1;
433
434                 /* Set default affinity mask once everything is setup */
435                 irq_select_affinity(irq);
436         }
437
438         *p = new;
439
440         /* Exclude IRQ from balancing */
441         if (new->flags & IRQF_NOBALANCING)
442                 desc->status |= IRQ_NO_BALANCING;
443
444         /* Reset broken irq detection when installing new handler */
445         desc->irq_count = 0;
446         desc->irqs_unhandled = 0;
447
448         /*
449          * Check whether we disabled the irq via the spurious handler
450          * before. Reenable it and give it another chance.
451          */
452         if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
453                 desc->status &= ~IRQ_SPURIOUS_DISABLED;
454                 __enable_irq(desc, irq);
455         }
456
457         spin_unlock_irqrestore(&desc->lock, flags);
458
459         new->irq = irq;
460         register_irq_proc(irq);
461         new->dir = NULL;
462         register_handler_proc(irq, new);
463
464         return 0;
465
466 mismatch:
467 #ifdef CONFIG_DEBUG_SHIRQ
468         if (!(new->flags & IRQF_PROBE_SHARED)) {
469                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
470                 if (old_name)
471                         printk(KERN_ERR "current handler: %s\n", old_name);
472                 dump_stack();
473         }
474 #endif
475         spin_unlock_irqrestore(&desc->lock, flags);
476         return -EBUSY;
477 }
478
479 /**
480  *      free_irq - free an interrupt
481  *      @irq: Interrupt line to free
482  *      @dev_id: Device identity to free
483  *
484  *      Remove an interrupt handler. The handler is removed and if the
485  *      interrupt line is no longer in use by any driver it is disabled.
486  *      On a shared IRQ the caller must ensure the interrupt is disabled
487  *      on the card it drives before calling this function. The function
488  *      does not return until any executing interrupts for this IRQ
489  *      have completed.
490  *
491  *      This function must not be called from interrupt context.
492  */
493 void free_irq(unsigned int irq, void *dev_id)
494 {
495         struct irq_desc *desc;
496         struct irqaction **p;
497         unsigned long flags;
498
499         WARN_ON(in_interrupt());
500         if (irq >= NR_IRQS)
501                 return;
502
503         desc = irq_desc + irq;
504         spin_lock_irqsave(&desc->lock, flags);
505         p = &desc->action;
506         for (;;) {
507                 struct irqaction *action = *p;
508
509                 if (action) {
510                         struct irqaction **pp = p;
511
512                         p = &action->next;
513                         if (action->dev_id != dev_id)
514                                 continue;
515
516                         /* Found it - now remove it from the list of entries */
517                         *pp = action->next;
518
519                         /* Currently used only by UML, might disappear one day.*/
520 #ifdef CONFIG_IRQ_RELEASE_METHOD
521                         if (desc->chip->release)
522                                 desc->chip->release(irq, dev_id);
523 #endif
524
525                         if (!desc->action) {
526                                 desc->status |= IRQ_DISABLED;
527                                 if (desc->chip->shutdown)
528                                         desc->chip->shutdown(irq);
529                                 else
530                                         desc->chip->disable(irq);
531                         }
532                         spin_unlock_irqrestore(&desc->lock, flags);
533                         unregister_handler_proc(irq, action);
534
535                         /* Make sure it's not being used on another CPU */
536                         synchronize_irq(irq);
537 #ifdef CONFIG_DEBUG_SHIRQ
538                         /*
539                          * It's a shared IRQ -- the driver ought to be
540                          * prepared for it to happen even now it's
541                          * being freed, so let's make sure....  We do
542                          * this after actually deregistering it, to
543                          * make sure that a 'real' IRQ doesn't run in
544                          * parallel with our fake
545                          */
546                         if (action->flags & IRQF_SHARED) {
547                                 local_irq_save(flags);
548                                 action->handler(irq, dev_id);
549                                 local_irq_restore(flags);
550                         }
551 #endif
552                         kfree(action);
553                         return;
554                 }
555                 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
556 #ifdef CONFIG_DEBUG_SHIRQ
557                 dump_stack();
558 #endif
559                 spin_unlock_irqrestore(&desc->lock, flags);
560                 return;
561         }
562 }
563 EXPORT_SYMBOL(free_irq);
564
565 /**
566  *      request_irq - allocate an interrupt line
567  *      @irq: Interrupt line to allocate
568  *      @handler: Function to be called when the IRQ occurs
569  *      @irqflags: Interrupt type flags
570  *      @devname: An ascii name for the claiming device
571  *      @dev_id: A cookie passed back to the handler function
572  *
573  *      This call allocates interrupt resources and enables the
574  *      interrupt line and IRQ handling. From the point this
575  *      call is made your handler function may be invoked. Since
576  *      your handler function must clear any interrupt the board
577  *      raises, you must take care both to initialise your hardware
578  *      and to set up the interrupt handler in the right order.
579  *
580  *      Dev_id must be globally unique. Normally the address of the
581  *      device data structure is used as the cookie. Since the handler
582  *      receives this value it makes sense to use it.
583  *
584  *      If your interrupt is shared you must pass a non NULL dev_id
585  *      as this is required when freeing the interrupt.
586  *
587  *      Flags:
588  *
589  *      IRQF_SHARED             Interrupt is shared
590  *      IRQF_DISABLED   Disable local interrupts while processing
591  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
592  *
593  */
594 int request_irq(unsigned int irq, irq_handler_t handler,
595                 unsigned long irqflags, const char *devname, void *dev_id)
596 {
597         struct irqaction *action;
598         int retval;
599
600 #ifdef CONFIG_LOCKDEP
601         /*
602          * Lockdep wants atomic interrupt handlers:
603          */
604         irqflags |= IRQF_DISABLED;
605 #endif
606         /*
607          * Sanity-check: shared interrupts must pass in a real dev-ID,
608          * otherwise we'll have trouble later trying to figure out
609          * which interrupt is which (messes up the interrupt freeing
610          * logic etc).
611          */
612         if ((irqflags & IRQF_SHARED) && !dev_id)
613                 return -EINVAL;
614         if (irq >= NR_IRQS)
615                 return -EINVAL;
616         if (irq_desc[irq].status & IRQ_NOREQUEST)
617                 return -EINVAL;
618         if (!handler)
619                 return -EINVAL;
620
621         action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
622         if (!action)
623                 return -ENOMEM;
624
625         action->handler = handler;
626         action->flags = irqflags;
627         cpus_clear(action->mask);
628         action->name = devname;
629         action->next = NULL;
630         action->dev_id = dev_id;
631
632 #ifdef CONFIG_DEBUG_SHIRQ
633         if (irqflags & IRQF_SHARED) {
634                 /*
635                  * It's a shared IRQ -- the driver ought to be prepared for it
636                  * to happen immediately, so let's make sure....
637                  * We do this before actually registering it, to make sure that
638                  * a 'real' IRQ doesn't run in parallel with our fake
639                  */
640                 unsigned long flags;
641
642                 local_irq_save(flags);
643                 handler(irq, dev_id);
644                 local_irq_restore(flags);
645         }
646 #endif
647
648         retval = setup_irq(irq, action);
649         if (retval)
650                 kfree(action);
651
652         return retval;
653 }
654 EXPORT_SYMBOL(request_irq);