cpumask: make irq_set_affinity() take a const struct cpumask
[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, const struct cpumask *cpumask)
83 {
84         struct irq_desc *desc = irq_to_desc(irq);
85         unsigned long flags;
86
87         if (!desc->chip->set_affinity)
88                 return -EINVAL;
89
90         spin_lock_irqsave(&desc->lock, flags);
91
92 #ifdef CONFIG_GENERIC_PENDING_IRQ
93         if (desc->status & IRQ_MOVE_PCNTXT || desc->status & IRQ_DISABLED) {
94                 cpumask_copy(&desc->affinity, cpumask);
95                 desc->chip->set_affinity(irq, cpumask);
96         } else {
97                 desc->status |= IRQ_MOVE_PENDING;
98                 cpumask_copy(&desc->pending_mask, cpumask);
99         }
100 #else
101         cpumask_copy(&desc->affinity, cpumask);
102         desc->chip->set_affinity(irq, cpumask);
103 #endif
104         desc->status |= IRQ_AFFINITY_SET;
105         spin_unlock_irqrestore(&desc->lock, flags);
106         return 0;
107 }
108
109 #ifndef CONFIG_AUTO_IRQ_AFFINITY
110 /*
111  * Generic version of the affinity autoselector.
112  */
113 int do_irq_select_affinity(unsigned int irq, struct irq_desc *desc)
114 {
115         if (!irq_can_set_affinity(irq))
116                 return 0;
117
118         /*
119          * Preserve an userspace affinity setup, but make sure that
120          * one of the targets is online.
121          */
122         if (desc->status & (IRQ_AFFINITY_SET | IRQ_NO_BALANCING)) {
123                 if (cpumask_any_and(&desc->affinity, cpu_online_mask)
124                     < nr_cpu_ids)
125                         goto set_affinity;
126                 else
127                         desc->status &= ~IRQ_AFFINITY_SET;
128         }
129
130         cpumask_and(&desc->affinity, cpu_online_mask, &irq_default_affinity);
131 set_affinity:
132         desc->chip->set_affinity(irq, &desc->affinity);
133
134         return 0;
135 }
136 #else
137 static inline int do_irq_select_affinity(unsigned int irq, struct irq_desc *d)
138 {
139         return irq_select_affinity(irq);
140 }
141 #endif
142
143 /*
144  * Called when affinity is set via /proc/irq
145  */
146 int irq_select_affinity_usr(unsigned int irq)
147 {
148         struct irq_desc *desc = irq_to_desc(irq);
149         unsigned long flags;
150         int ret;
151
152         spin_lock_irqsave(&desc->lock, flags);
153         ret = do_irq_select_affinity(irq, desc);
154         spin_unlock_irqrestore(&desc->lock, flags);
155
156         return ret;
157 }
158
159 #else
160 static inline int do_irq_select_affinity(int irq, struct irq_desc *desc)
161 {
162         return 0;
163 }
164 #endif
165
166 /**
167  *      disable_irq_nosync - disable an irq without waiting
168  *      @irq: Interrupt to disable
169  *
170  *      Disable the selected interrupt line.  Disables and Enables are
171  *      nested.
172  *      Unlike disable_irq(), this function does not ensure existing
173  *      instances of the IRQ handler have completed before returning.
174  *
175  *      This function may be called from IRQ context.
176  */
177 void disable_irq_nosync(unsigned int irq)
178 {
179         struct irq_desc *desc = irq_to_desc(irq);
180         unsigned long flags;
181
182         if (!desc)
183                 return;
184
185         spin_lock_irqsave(&desc->lock, flags);
186         if (!desc->depth++) {
187                 desc->status |= IRQ_DISABLED;
188                 desc->chip->disable(irq);
189         }
190         spin_unlock_irqrestore(&desc->lock, flags);
191 }
192 EXPORT_SYMBOL(disable_irq_nosync);
193
194 /**
195  *      disable_irq - disable an irq and wait for completion
196  *      @irq: Interrupt to disable
197  *
198  *      Disable the selected interrupt line.  Enables and Disables are
199  *      nested.
200  *      This function waits for any pending IRQ handlers for this interrupt
201  *      to complete before returning. If you use this function while
202  *      holding a resource the IRQ handler may need you will deadlock.
203  *
204  *      This function may be called - with care - from IRQ context.
205  */
206 void disable_irq(unsigned int irq)
207 {
208         struct irq_desc *desc = irq_to_desc(irq);
209
210         if (!desc)
211                 return;
212
213         disable_irq_nosync(irq);
214         if (desc->action)
215                 synchronize_irq(irq);
216 }
217 EXPORT_SYMBOL(disable_irq);
218
219 static void __enable_irq(struct irq_desc *desc, unsigned int irq)
220 {
221         switch (desc->depth) {
222         case 0:
223                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
224                 break;
225         case 1: {
226                 unsigned int status = desc->status & ~IRQ_DISABLED;
227
228                 /* Prevent probing on this irq: */
229                 desc->status = status | IRQ_NOPROBE;
230                 check_irq_resend(desc, irq);
231                 /* fall-through */
232         }
233         default:
234                 desc->depth--;
235         }
236 }
237
238 /**
239  *      enable_irq - enable handling of an irq
240  *      @irq: Interrupt to enable
241  *
242  *      Undoes the effect of one call to disable_irq().  If this
243  *      matches the last disable, processing of interrupts on this
244  *      IRQ line is re-enabled.
245  *
246  *      This function may be called from IRQ context.
247  */
248 void enable_irq(unsigned int irq)
249 {
250         struct irq_desc *desc = irq_to_desc(irq);
251         unsigned long flags;
252
253         if (!desc)
254                 return;
255
256         spin_lock_irqsave(&desc->lock, flags);
257         __enable_irq(desc, irq);
258         spin_unlock_irqrestore(&desc->lock, flags);
259 }
260 EXPORT_SYMBOL(enable_irq);
261
262 static int set_irq_wake_real(unsigned int irq, unsigned int on)
263 {
264         struct irq_desc *desc = irq_to_desc(irq);
265         int ret = -ENXIO;
266
267         if (desc->chip->set_wake)
268                 ret = desc->chip->set_wake(irq, on);
269
270         return ret;
271 }
272
273 /**
274  *      set_irq_wake - control irq power management wakeup
275  *      @irq:   interrupt to control
276  *      @on:    enable/disable power management wakeup
277  *
278  *      Enable/disable power management wakeup mode, which is
279  *      disabled by default.  Enables and disables must match,
280  *      just as they match for non-wakeup mode support.
281  *
282  *      Wakeup mode lets this IRQ wake the system from sleep
283  *      states like "suspend to RAM".
284  */
285 int set_irq_wake(unsigned int irq, unsigned int on)
286 {
287         struct irq_desc *desc = irq_to_desc(irq);
288         unsigned long flags;
289         int ret = 0;
290
291         /* wakeup-capable irqs can be shared between drivers that
292          * don't need to have the same sleep mode behaviors.
293          */
294         spin_lock_irqsave(&desc->lock, flags);
295         if (on) {
296                 if (desc->wake_depth++ == 0) {
297                         ret = set_irq_wake_real(irq, on);
298                         if (ret)
299                                 desc->wake_depth = 0;
300                         else
301                                 desc->status |= IRQ_WAKEUP;
302                 }
303         } else {
304                 if (desc->wake_depth == 0) {
305                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
306                 } else if (--desc->wake_depth == 0) {
307                         ret = set_irq_wake_real(irq, on);
308                         if (ret)
309                                 desc->wake_depth = 1;
310                         else
311                                 desc->status &= ~IRQ_WAKEUP;
312                 }
313         }
314
315         spin_unlock_irqrestore(&desc->lock, flags);
316         return ret;
317 }
318 EXPORT_SYMBOL(set_irq_wake);
319
320 /*
321  * Internal function that tells the architecture code whether a
322  * particular irq has been exclusively allocated or is available
323  * for driver use.
324  */
325 int can_request_irq(unsigned int irq, unsigned long irqflags)
326 {
327         struct irq_desc *desc = irq_to_desc(irq);
328         struct irqaction *action;
329
330         if (!desc)
331                 return 0;
332
333         if (desc->status & IRQ_NOREQUEST)
334                 return 0;
335
336         action = desc->action;
337         if (action)
338                 if (irqflags & action->flags & IRQF_SHARED)
339                         action = NULL;
340
341         return !action;
342 }
343
344 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
345 {
346         /*
347          * If the architecture still has not overriden
348          * the flow handler then zap the default. This
349          * should catch incorrect flow-type setting.
350          */
351         if (desc->handle_irq == &handle_bad_irq)
352                 desc->handle_irq = NULL;
353 }
354
355 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
356                 unsigned long flags)
357 {
358         int ret;
359         struct irq_chip *chip = desc->chip;
360
361         if (!chip || !chip->set_type) {
362                 /*
363                  * IRQF_TRIGGER_* but the PIC does not support multiple
364                  * flow-types?
365                  */
366                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
367                                 chip ? (chip->name ? : "unknown") : "unknown");
368                 return 0;
369         }
370
371         ret = chip->set_type(irq, flags & IRQF_TRIGGER_MASK);
372
373         if (ret)
374                 pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
375                                 (int)(flags & IRQF_TRIGGER_MASK),
376                                 irq, chip->set_type);
377         else {
378                 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
379                 desc->status &= ~IRQ_TYPE_SENSE_MASK;
380                 desc->status |= flags & IRQ_TYPE_SENSE_MASK;
381         }
382
383         return ret;
384 }
385
386 /*
387  * Internal function to register an irqaction - typically used to
388  * allocate special interrupts that are part of the architecture.
389  */
390 static int
391 __setup_irq(unsigned int irq, struct irq_desc * desc, struct irqaction *new)
392 {
393         struct irqaction *old, **p;
394         const char *old_name = NULL;
395         unsigned long flags;
396         int shared = 0;
397         int ret;
398
399         if (!desc)
400                 return -EINVAL;
401
402         if (desc->chip == &no_irq_chip)
403                 return -ENOSYS;
404         /*
405          * Some drivers like serial.c use request_irq() heavily,
406          * so we have to be careful not to interfere with a
407          * running system.
408          */
409         if (new->flags & IRQF_SAMPLE_RANDOM) {
410                 /*
411                  * This function might sleep, we want to call it first,
412                  * outside of the atomic block.
413                  * Yes, this might clear the entropy pool if the wrong
414                  * driver is attempted to be loaded, without actually
415                  * installing a new handler, but is this really a problem,
416                  * only the sysadmin is able to do this.
417                  */
418                 rand_initialize_irq(irq);
419         }
420
421         /*
422          * The following block of code has to be executed atomically
423          */
424         spin_lock_irqsave(&desc->lock, flags);
425         p = &desc->action;
426         old = *p;
427         if (old) {
428                 /*
429                  * Can't share interrupts unless both agree to and are
430                  * the same type (level, edge, polarity). So both flag
431                  * fields must have IRQF_SHARED set and the bits which
432                  * set the trigger type must match.
433                  */
434                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
435                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
436                         old_name = old->name;
437                         goto mismatch;
438                 }
439
440 #if defined(CONFIG_IRQ_PER_CPU)
441                 /* All handlers must agree on per-cpuness */
442                 if ((old->flags & IRQF_PERCPU) !=
443                     (new->flags & IRQF_PERCPU))
444                         goto mismatch;
445 #endif
446
447                 /* add new interrupt at end of irq queue */
448                 do {
449                         p = &old->next;
450                         old = *p;
451                 } while (old);
452                 shared = 1;
453         }
454
455         if (!shared) {
456                 irq_chip_set_defaults(desc->chip);
457
458                 /* Setup the type (level, edge polarity) if configured: */
459                 if (new->flags & IRQF_TRIGGER_MASK) {
460                         ret = __irq_set_trigger(desc, irq, new->flags);
461
462                         if (ret) {
463                                 spin_unlock_irqrestore(&desc->lock, flags);
464                                 return ret;
465                         }
466                 } else
467                         compat_irq_chip_set_default_handler(desc);
468 #if defined(CONFIG_IRQ_PER_CPU)
469                 if (new->flags & IRQF_PERCPU)
470                         desc->status |= IRQ_PER_CPU;
471 #endif
472
473                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
474                                   IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
475
476                 if (!(desc->status & IRQ_NOAUTOEN)) {
477                         desc->depth = 0;
478                         desc->status &= ~IRQ_DISABLED;
479                         desc->chip->startup(irq);
480                 } else
481                         /* Undo nested disables: */
482                         desc->depth = 1;
483
484                 /* Exclude IRQ from balancing if requested */
485                 if (new->flags & IRQF_NOBALANCING)
486                         desc->status |= IRQ_NO_BALANCING;
487
488                 /* Set default affinity mask once everything is setup */
489                 do_irq_select_affinity(irq, desc);
490
491         } else if ((new->flags & IRQF_TRIGGER_MASK)
492                         && (new->flags & IRQF_TRIGGER_MASK)
493                                 != (desc->status & IRQ_TYPE_SENSE_MASK)) {
494                 /* hope the handler works with the actual trigger mode... */
495                 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
496                                 irq, (int)(desc->status & IRQ_TYPE_SENSE_MASK),
497                                 (int)(new->flags & IRQF_TRIGGER_MASK));
498         }
499
500         *p = new;
501
502         /* Reset broken irq detection when installing new handler */
503         desc->irq_count = 0;
504         desc->irqs_unhandled = 0;
505
506         /*
507          * Check whether we disabled the irq via the spurious handler
508          * before. Reenable it and give it another chance.
509          */
510         if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
511                 desc->status &= ~IRQ_SPURIOUS_DISABLED;
512                 __enable_irq(desc, irq);
513         }
514
515         spin_unlock_irqrestore(&desc->lock, flags);
516
517         new->irq = irq;
518         register_irq_proc(irq, desc);
519         new->dir = NULL;
520         register_handler_proc(irq, new);
521
522         return 0;
523
524 mismatch:
525 #ifdef CONFIG_DEBUG_SHIRQ
526         if (!(new->flags & IRQF_PROBE_SHARED)) {
527                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
528                 if (old_name)
529                         printk(KERN_ERR "current handler: %s\n", old_name);
530                 dump_stack();
531         }
532 #endif
533         spin_unlock_irqrestore(&desc->lock, flags);
534         return -EBUSY;
535 }
536
537 /**
538  *      setup_irq - setup an interrupt
539  *      @irq: Interrupt line to setup
540  *      @act: irqaction for the interrupt
541  *
542  * Used to statically setup interrupts in the early boot process.
543  */
544 int setup_irq(unsigned int irq, struct irqaction *act)
545 {
546         struct irq_desc *desc = irq_to_desc(irq);
547
548         return __setup_irq(irq, desc, act);
549 }
550
551 /**
552  *      free_irq - free an interrupt
553  *      @irq: Interrupt line to free
554  *      @dev_id: Device identity to free
555  *
556  *      Remove an interrupt handler. The handler is removed and if the
557  *      interrupt line is no longer in use by any driver it is disabled.
558  *      On a shared IRQ the caller must ensure the interrupt is disabled
559  *      on the card it drives before calling this function. The function
560  *      does not return until any executing interrupts for this IRQ
561  *      have completed.
562  *
563  *      This function must not be called from interrupt context.
564  */
565 void free_irq(unsigned int irq, void *dev_id)
566 {
567         struct irq_desc *desc = irq_to_desc(irq);
568         struct irqaction **p;
569         unsigned long flags;
570
571         WARN_ON(in_interrupt());
572
573         if (!desc)
574                 return;
575
576         spin_lock_irqsave(&desc->lock, flags);
577         p = &desc->action;
578         for (;;) {
579                 struct irqaction *action = *p;
580
581                 if (action) {
582                         struct irqaction **pp = p;
583
584                         p = &action->next;
585                         if (action->dev_id != dev_id)
586                                 continue;
587
588                         /* Found it - now remove it from the list of entries */
589                         *pp = action->next;
590
591                         /* Currently used only by UML, might disappear one day.*/
592 #ifdef CONFIG_IRQ_RELEASE_METHOD
593                         if (desc->chip->release)
594                                 desc->chip->release(irq, dev_id);
595 #endif
596
597                         if (!desc->action) {
598                                 desc->status |= IRQ_DISABLED;
599                                 if (desc->chip->shutdown)
600                                         desc->chip->shutdown(irq);
601                                 else
602                                         desc->chip->disable(irq);
603                         }
604                         spin_unlock_irqrestore(&desc->lock, flags);
605                         unregister_handler_proc(irq, action);
606
607                         /* Make sure it's not being used on another CPU */
608                         synchronize_irq(irq);
609 #ifdef CONFIG_DEBUG_SHIRQ
610                         /*
611                          * It's a shared IRQ -- the driver ought to be
612                          * prepared for it to happen even now it's
613                          * being freed, so let's make sure....  We do
614                          * this after actually deregistering it, to
615                          * make sure that a 'real' IRQ doesn't run in
616                          * parallel with our fake
617                          */
618                         if (action->flags & IRQF_SHARED) {
619                                 local_irq_save(flags);
620                                 action->handler(irq, dev_id);
621                                 local_irq_restore(flags);
622                         }
623 #endif
624                         kfree(action);
625                         return;
626                 }
627                 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
628 #ifdef CONFIG_DEBUG_SHIRQ
629                 dump_stack();
630 #endif
631                 spin_unlock_irqrestore(&desc->lock, flags);
632                 return;
633         }
634 }
635 EXPORT_SYMBOL(free_irq);
636
637 /**
638  *      request_irq - allocate an interrupt line
639  *      @irq: Interrupt line to allocate
640  *      @handler: Function to be called when the IRQ occurs
641  *      @irqflags: Interrupt type flags
642  *      @devname: An ascii name for the claiming device
643  *      @dev_id: A cookie passed back to the handler function
644  *
645  *      This call allocates interrupt resources and enables the
646  *      interrupt line and IRQ handling. From the point this
647  *      call is made your handler function may be invoked. Since
648  *      your handler function must clear any interrupt the board
649  *      raises, you must take care both to initialise your hardware
650  *      and to set up the interrupt handler in the right order.
651  *
652  *      Dev_id must be globally unique. Normally the address of the
653  *      device data structure is used as the cookie. Since the handler
654  *      receives this value it makes sense to use it.
655  *
656  *      If your interrupt is shared you must pass a non NULL dev_id
657  *      as this is required when freeing the interrupt.
658  *
659  *      Flags:
660  *
661  *      IRQF_SHARED             Interrupt is shared
662  *      IRQF_DISABLED   Disable local interrupts while processing
663  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
664  *      IRQF_TRIGGER_*          Specify active edge(s) or level
665  *
666  */
667 int request_irq(unsigned int irq, irq_handler_t handler,
668                 unsigned long irqflags, const char *devname, void *dev_id)
669 {
670         struct irqaction *action;
671         struct irq_desc *desc;
672         int retval;
673
674 #ifdef CONFIG_LOCKDEP
675         /*
676          * Lockdep wants atomic interrupt handlers:
677          */
678         irqflags |= IRQF_DISABLED;
679 #endif
680         /*
681          * Sanity-check: shared interrupts must pass in a real dev-ID,
682          * otherwise we'll have trouble later trying to figure out
683          * which interrupt is which (messes up the interrupt freeing
684          * logic etc).
685          */
686         if ((irqflags & IRQF_SHARED) && !dev_id)
687                 return -EINVAL;
688
689         desc = irq_to_desc(irq);
690         if (!desc)
691                 return -EINVAL;
692
693         if (desc->status & IRQ_NOREQUEST)
694                 return -EINVAL;
695         if (!handler)
696                 return -EINVAL;
697
698         action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
699         if (!action)
700                 return -ENOMEM;
701
702         action->handler = handler;
703         action->flags = irqflags;
704         cpus_clear(action->mask);
705         action->name = devname;
706         action->next = NULL;
707         action->dev_id = dev_id;
708
709         retval = __setup_irq(irq, desc, action);
710         if (retval)
711                 kfree(action);
712
713 #ifdef CONFIG_DEBUG_SHIRQ
714         if (irqflags & IRQF_SHARED) {
715                 /*
716                  * It's a shared IRQ -- the driver ought to be prepared for it
717                  * to happen immediately, so let's make sure....
718                  * We disable the irq to make sure that a 'real' IRQ doesn't
719                  * run in parallel with our fake.
720                  */
721                 unsigned long flags;
722
723                 disable_irq(irq);
724                 local_irq_save(flags);
725
726                 handler(irq, dev_id);
727
728                 local_irq_restore(flags);
729                 enable_irq(irq);
730         }
731 #endif
732         return retval;
733 }
734 EXPORT_SYMBOL(request_irq);