genirq: cleanup the sparseirq modifications
[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_to_desc(irq);
35         unsigned int status;
36
37         if (!desc)
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_to_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_to_desc(irq);
85
86         if (!desc->chip->set_affinity)
87                 return -EINVAL;
88
89 #ifdef CONFIG_GENERIC_PENDING_IRQ
90         if (desc->status & IRQ_MOVE_PCNTXT || desc->status & IRQ_DISABLED) {
91                 unsigned long flags;
92
93                 spin_lock_irqsave(&desc->lock, flags);
94                 desc->affinity = cpumask;
95                 desc->chip->set_affinity(irq, cpumask);
96                 spin_unlock_irqrestore(&desc->lock, flags);
97         } else
98                 set_pending_irq(irq, cpumask);
99 #else
100         desc->affinity = cpumask;
101         desc->chip->set_affinity(irq, cpumask);
102 #endif
103         return 0;
104 }
105
106 #ifndef CONFIG_AUTO_IRQ_AFFINITY
107 /*
108  * Generic version of the affinity autoselector.
109  */
110 int irq_select_affinity(unsigned int irq)
111 {
112         cpumask_t mask;
113         struct irq_desc *desc;
114
115         if (!irq_can_set_affinity(irq))
116                 return 0;
117
118         cpus_and(mask, cpu_online_map, irq_default_affinity);
119
120         desc = irq_to_desc(irq);
121         desc->affinity = mask;
122         desc->chip->set_affinity(irq, mask);
123
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_to_desc(irq);
144         unsigned long flags;
145
146         if (!desc)
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_to_desc(irq);
173
174         if (!desc)
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_to_desc(irq);
215         unsigned long flags;
216
217         if (!desc)
218                 return;
219
220         spin_lock_irqsave(&desc->lock, flags);
221         __enable_irq(desc, irq);
222         spin_unlock_irqrestore(&desc->lock, flags);
223 }
224 EXPORT_SYMBOL(enable_irq);
225
226 static int set_irq_wake_real(unsigned int irq, unsigned int on)
227 {
228         struct irq_desc *desc = irq_to_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_to_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 irq_desc *desc = irq_to_desc(irq);
292         struct irqaction *action;
293
294         if (!desc)
295                 return 0;
296
297         if (desc->status & IRQ_NOREQUEST)
298                 return 0;
299
300         action = desc->action;
301         if (action)
302                 if (irqflags & action->flags & IRQF_SHARED)
303                         action = NULL;
304
305         return !action;
306 }
307
308 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
309 {
310         /*
311          * If the architecture still has not overriden
312          * the flow handler then zap the default. This
313          * should catch incorrect flow-type setting.
314          */
315         if (desc->handle_irq == &handle_bad_irq)
316                 desc->handle_irq = NULL;
317 }
318
319 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
320                 unsigned long flags)
321 {
322         int ret;
323         struct irq_chip *chip = desc->chip;
324
325         if (!chip || !chip->set_type) {
326                 /*
327                  * IRQF_TRIGGER_* but the PIC does not support multiple
328                  * flow-types?
329                  */
330                 pr_warning("No set_type function for IRQ %d (%s)\n", irq,
331                                 chip ? (chip->name ? : "unknown") : "unknown");
332                 return 0;
333         }
334
335         ret = chip->set_type(irq, flags & IRQF_TRIGGER_MASK);
336
337         if (ret)
338                 pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
339                                 (int)(flags & IRQF_TRIGGER_MASK),
340                                 irq, chip->set_type);
341         else {
342                 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
343                 desc->status &= ~IRQ_TYPE_SENSE_MASK;
344                 desc->status |= flags & IRQ_TYPE_SENSE_MASK;
345         }
346
347         return ret;
348 }
349
350 /*
351  * Internal function to register an irqaction - typically used to
352  * allocate special interrupts that are part of the architecture.
353  */
354 static int
355 __setup_irq(unsigned int irq, struct irq_desc * desc, struct irqaction *new)
356 {
357         struct irqaction *old, **p;
358         const char *old_name = NULL;
359         unsigned long flags;
360         int shared = 0;
361         int ret;
362
363         if (!desc)
364                 return -EINVAL;
365
366         if (desc->chip == &no_irq_chip)
367                 return -ENOSYS;
368         /*
369          * Some drivers like serial.c use request_irq() heavily,
370          * so we have to be careful not to interfere with a
371          * running system.
372          */
373         if (new->flags & IRQF_SAMPLE_RANDOM) {
374                 /*
375                  * This function might sleep, we want to call it first,
376                  * outside of the atomic block.
377                  * Yes, this might clear the entropy pool if the wrong
378                  * driver is attempted to be loaded, without actually
379                  * installing a new handler, but is this really a problem,
380                  * only the sysadmin is able to do this.
381                  */
382                 rand_initialize_irq(irq);
383         }
384
385         /*
386          * The following block of code has to be executed atomically
387          */
388         spin_lock_irqsave(&desc->lock, flags);
389         p = &desc->action;
390         old = *p;
391         if (old) {
392                 /*
393                  * Can't share interrupts unless both agree to and are
394                  * the same type (level, edge, polarity). So both flag
395                  * fields must have IRQF_SHARED set and the bits which
396                  * set the trigger type must match.
397                  */
398                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
399                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
400                         old_name = old->name;
401                         goto mismatch;
402                 }
403
404 #if defined(CONFIG_IRQ_PER_CPU)
405                 /* All handlers must agree on per-cpuness */
406                 if ((old->flags & IRQF_PERCPU) !=
407                     (new->flags & IRQF_PERCPU))
408                         goto mismatch;
409 #endif
410
411                 /* add new interrupt at end of irq queue */
412                 do {
413                         p = &old->next;
414                         old = *p;
415                 } while (old);
416                 shared = 1;
417         }
418
419         if (!shared) {
420                 irq_chip_set_defaults(desc->chip);
421
422                 /* Setup the type (level, edge polarity) if configured: */
423                 if (new->flags & IRQF_TRIGGER_MASK) {
424                         ret = __irq_set_trigger(desc, irq, new->flags);
425
426                         if (ret) {
427                                 spin_unlock_irqrestore(&desc->lock, flags);
428                                 return ret;
429                         }
430                 } else
431                         compat_irq_chip_set_default_handler(desc);
432 #if defined(CONFIG_IRQ_PER_CPU)
433                 if (new->flags & IRQF_PERCPU)
434                         desc->status |= IRQ_PER_CPU;
435 #endif
436
437                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
438                                   IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
439
440                 if (!(desc->status & IRQ_NOAUTOEN)) {
441                         desc->depth = 0;
442                         desc->status &= ~IRQ_DISABLED;
443                         desc->chip->startup(irq);
444                 } else
445                         /* Undo nested disables: */
446                         desc->depth = 1;
447
448                 /* Set default affinity mask once everything is setup */
449                 irq_select_affinity(irq);
450
451         } else if ((new->flags & IRQF_TRIGGER_MASK)
452                         && (new->flags & IRQF_TRIGGER_MASK)
453                                 != (desc->status & IRQ_TYPE_SENSE_MASK)) {
454                 /* hope the handler works with the actual trigger mode... */
455                 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
456                                 irq, (int)(desc->status & IRQ_TYPE_SENSE_MASK),
457                                 (int)(new->flags & IRQF_TRIGGER_MASK));
458         }
459
460         *p = new;
461
462         /* Exclude IRQ from balancing */
463         if (new->flags & IRQF_NOBALANCING)
464                 desc->status |= IRQ_NO_BALANCING;
465
466         /* Reset broken irq detection when installing new handler */
467         desc->irq_count = 0;
468         desc->irqs_unhandled = 0;
469
470         /*
471          * Check whether we disabled the irq via the spurious handler
472          * before. Reenable it and give it another chance.
473          */
474         if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
475                 desc->status &= ~IRQ_SPURIOUS_DISABLED;
476                 __enable_irq(desc, irq);
477         }
478
479         spin_unlock_irqrestore(&desc->lock, flags);
480
481         new->irq = irq;
482         register_irq_proc(irq, desc);
483         new->dir = NULL;
484         register_handler_proc(irq, new);
485
486         return 0;
487
488 mismatch:
489 #ifdef CONFIG_DEBUG_SHIRQ
490         if (!(new->flags & IRQF_PROBE_SHARED)) {
491                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
492                 if (old_name)
493                         printk(KERN_ERR "current handler: %s\n", old_name);
494                 dump_stack();
495         }
496 #endif
497         spin_unlock_irqrestore(&desc->lock, flags);
498         return -EBUSY;
499 }
500
501 /**
502  *      setup_irq - setup an interrupt
503  *      @irq: Interrupt line to setup
504  *      @act: irqaction for the interrupt
505  *
506  * Used to statically setup interrupts in the early boot process.
507  */
508 int setup_irq(unsigned int irq, struct irqaction *act)
509 {
510         struct irq_desc *desc = irq_to_desc(irq);
511
512         return __setup_irq(irq, desc, act);
513 }
514
515 /**
516  *      free_irq - free an interrupt
517  *      @irq: Interrupt line to free
518  *      @dev_id: Device identity to free
519  *
520  *      Remove an interrupt handler. The handler is removed and if the
521  *      interrupt line is no longer in use by any driver it is disabled.
522  *      On a shared IRQ the caller must ensure the interrupt is disabled
523  *      on the card it drives before calling this function. The function
524  *      does not return until any executing interrupts for this IRQ
525  *      have completed.
526  *
527  *      This function must not be called from interrupt context.
528  */
529 void free_irq(unsigned int irq, void *dev_id)
530 {
531         struct irq_desc *desc = irq_to_desc(irq);
532         struct irqaction **p;
533         unsigned long flags;
534
535         WARN_ON(in_interrupt());
536
537         if (!desc)
538                 return;
539
540         spin_lock_irqsave(&desc->lock, flags);
541         p = &desc->action;
542         for (;;) {
543                 struct irqaction *action = *p;
544
545                 if (action) {
546                         struct irqaction **pp = p;
547
548                         p = &action->next;
549                         if (action->dev_id != dev_id)
550                                 continue;
551
552                         /* Found it - now remove it from the list of entries */
553                         *pp = action->next;
554
555                         /* Currently used only by UML, might disappear one day.*/
556 #ifdef CONFIG_IRQ_RELEASE_METHOD
557                         if (desc->chip->release)
558                                 desc->chip->release(irq, dev_id);
559 #endif
560
561                         if (!desc->action) {
562                                 desc->status |= IRQ_DISABLED;
563                                 if (desc->chip->shutdown)
564                                         desc->chip->shutdown(irq);
565                                 else
566                                         desc->chip->disable(irq);
567                         }
568                         spin_unlock_irqrestore(&desc->lock, flags);
569                         unregister_handler_proc(irq, action);
570
571                         /* Make sure it's not being used on another CPU */
572                         synchronize_irq(irq);
573 #ifdef CONFIG_DEBUG_SHIRQ
574                         /*
575                          * It's a shared IRQ -- the driver ought to be
576                          * prepared for it to happen even now it's
577                          * being freed, so let's make sure....  We do
578                          * this after actually deregistering it, to
579                          * make sure that a 'real' IRQ doesn't run in
580                          * parallel with our fake
581                          */
582                         if (action->flags & IRQF_SHARED) {
583                                 local_irq_save(flags);
584                                 action->handler(irq, dev_id);
585                                 local_irq_restore(flags);
586                         }
587 #endif
588                         kfree(action);
589                         return;
590                 }
591                 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
592 #ifdef CONFIG_DEBUG_SHIRQ
593                 dump_stack();
594 #endif
595                 spin_unlock_irqrestore(&desc->lock, flags);
596                 return;
597         }
598 }
599 EXPORT_SYMBOL(free_irq);
600
601 /**
602  *      request_irq - allocate an interrupt line
603  *      @irq: Interrupt line to allocate
604  *      @handler: Function to be called when the IRQ occurs
605  *      @irqflags: Interrupt type flags
606  *      @devname: An ascii name for the claiming device
607  *      @dev_id: A cookie passed back to the handler function
608  *
609  *      This call allocates interrupt resources and enables the
610  *      interrupt line and IRQ handling. From the point this
611  *      call is made your handler function may be invoked. Since
612  *      your handler function must clear any interrupt the board
613  *      raises, you must take care both to initialise your hardware
614  *      and to set up the interrupt handler in the right order.
615  *
616  *      Dev_id must be globally unique. Normally the address of the
617  *      device data structure is used as the cookie. Since the handler
618  *      receives this value it makes sense to use it.
619  *
620  *      If your interrupt is shared you must pass a non NULL dev_id
621  *      as this is required when freeing the interrupt.
622  *
623  *      Flags:
624  *
625  *      IRQF_SHARED             Interrupt is shared
626  *      IRQF_DISABLED   Disable local interrupts while processing
627  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
628  *      IRQF_TRIGGER_*          Specify active edge(s) or level
629  *
630  */
631 int request_irq(unsigned int irq, irq_handler_t handler,
632                 unsigned long irqflags, const char *devname, void *dev_id)
633 {
634         struct irqaction *action;
635         struct irq_desc *desc;
636         int retval;
637
638 #ifdef CONFIG_LOCKDEP
639         /*
640          * Lockdep wants atomic interrupt handlers:
641          */
642         irqflags |= IRQF_DISABLED;
643 #endif
644         /*
645          * Sanity-check: shared interrupts must pass in a real dev-ID,
646          * otherwise we'll have trouble later trying to figure out
647          * which interrupt is which (messes up the interrupt freeing
648          * logic etc).
649          */
650         if ((irqflags & IRQF_SHARED) && !dev_id)
651                 return -EINVAL;
652
653         desc = irq_to_desc(irq);
654         if (!desc)
655                 return -EINVAL;
656
657         if (desc->status & IRQ_NOREQUEST)
658                 return -EINVAL;
659         if (!handler)
660                 return -EINVAL;
661
662         action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
663         if (!action)
664                 return -ENOMEM;
665
666         action->handler = handler;
667         action->flags = irqflags;
668         cpus_clear(action->mask);
669         action->name = devname;
670         action->next = NULL;
671         action->dev_id = dev_id;
672
673         retval = __setup_irq(irq, desc, action);
674         if (retval)
675                 kfree(action);
676
677 #ifdef CONFIG_DEBUG_SHIRQ
678         if (irqflags & IRQF_SHARED) {
679                 /*
680                  * It's a shared IRQ -- the driver ought to be prepared for it
681                  * to happen immediately, so let's make sure....
682                  * We disable the irq to make sure that a 'real' IRQ doesn't
683                  * run in parallel with our fake.
684                  */
685                 unsigned long flags;
686
687                 disable_irq(irq);
688                 local_irq_save(flags);
689
690                 handler(irq, dev_id);
691
692                 local_irq_restore(flags);
693                 enable_irq(irq);
694         }
695 #endif
696         return retval;
697 }
698 EXPORT_SYMBOL(request_irq);