Merge branch 'linus' into x86/x2apic
[sfrench/cifs-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 /**
228  *      set_irq_wake - control irq power management wakeup
229  *      @irq:   interrupt to control
230  *      @on:    enable/disable power management wakeup
231  *
232  *      Enable/disable power management wakeup mode, which is
233  *      disabled by default.  Enables and disables must match,
234  *      just as they match for non-wakeup mode support.
235  *
236  *      Wakeup mode lets this IRQ wake the system from sleep
237  *      states like "suspend to RAM".
238  */
239 int set_irq_wake(unsigned int irq, unsigned int on)
240 {
241         struct irq_desc *desc = irq_desc + irq;
242         unsigned long flags;
243         int ret = -ENXIO;
244         int (*set_wake)(unsigned, unsigned) = desc->chip->set_wake;
245
246         /* wakeup-capable irqs can be shared between drivers that
247          * don't need to have the same sleep mode behaviors.
248          */
249         spin_lock_irqsave(&desc->lock, flags);
250         if (on) {
251                 if (desc->wake_depth++ == 0)
252                         desc->status |= IRQ_WAKEUP;
253                 else
254                         set_wake = NULL;
255         } else {
256                 if (desc->wake_depth == 0) {
257                         printk(KERN_WARNING "Unbalanced IRQ %d "
258                                         "wake disable\n", irq);
259                         WARN_ON(1);
260                 } else if (--desc->wake_depth == 0)
261                         desc->status &= ~IRQ_WAKEUP;
262                 else
263                         set_wake = NULL;
264         }
265         if (set_wake)
266                 ret = desc->chip->set_wake(irq, on);
267         spin_unlock_irqrestore(&desc->lock, flags);
268         return ret;
269 }
270 EXPORT_SYMBOL(set_irq_wake);
271
272 /*
273  * Internal function that tells the architecture code whether a
274  * particular irq has been exclusively allocated or is available
275  * for driver use.
276  */
277 int can_request_irq(unsigned int irq, unsigned long irqflags)
278 {
279         struct irqaction *action;
280
281         if (irq >= NR_IRQS || irq_desc[irq].status & IRQ_NOREQUEST)
282                 return 0;
283
284         action = irq_desc[irq].action;
285         if (action)
286                 if (irqflags & action->flags & IRQF_SHARED)
287                         action = NULL;
288
289         return !action;
290 }
291
292 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
293 {
294         /*
295          * If the architecture still has not overriden
296          * the flow handler then zap the default. This
297          * should catch incorrect flow-type setting.
298          */
299         if (desc->handle_irq == &handle_bad_irq)
300                 desc->handle_irq = NULL;
301 }
302
303 /*
304  * Internal function to register an irqaction - typically used to
305  * allocate special interrupts that are part of the architecture.
306  */
307 int setup_irq(unsigned int irq, struct irqaction *new)
308 {
309         struct irq_desc *desc = irq_desc + irq;
310         struct irqaction *old, **p;
311         const char *old_name = NULL;
312         unsigned long flags;
313         int shared = 0;
314
315         if (irq >= NR_IRQS)
316                 return -EINVAL;
317
318         if (desc->chip == &no_irq_chip)
319                 return -ENOSYS;
320         /*
321          * Some drivers like serial.c use request_irq() heavily,
322          * so we have to be careful not to interfere with a
323          * running system.
324          */
325         if (new->flags & IRQF_SAMPLE_RANDOM) {
326                 /*
327                  * This function might sleep, we want to call it first,
328                  * outside of the atomic block.
329                  * Yes, this might clear the entropy pool if the wrong
330                  * driver is attempted to be loaded, without actually
331                  * installing a new handler, but is this really a problem,
332                  * only the sysadmin is able to do this.
333                  */
334                 rand_initialize_irq(irq);
335         }
336
337         /*
338          * The following block of code has to be executed atomically
339          */
340         spin_lock_irqsave(&desc->lock, flags);
341         p = &desc->action;
342         old = *p;
343         if (old) {
344                 /*
345                  * Can't share interrupts unless both agree to and are
346                  * the same type (level, edge, polarity). So both flag
347                  * fields must have IRQF_SHARED set and the bits which
348                  * set the trigger type must match.
349                  */
350                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
351                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
352                         old_name = old->name;
353                         goto mismatch;
354                 }
355
356 #if defined(CONFIG_IRQ_PER_CPU)
357                 /* All handlers must agree on per-cpuness */
358                 if ((old->flags & IRQF_PERCPU) !=
359                     (new->flags & IRQF_PERCPU))
360                         goto mismatch;
361 #endif
362
363                 /* add new interrupt at end of irq queue */
364                 do {
365                         p = &old->next;
366                         old = *p;
367                 } while (old);
368                 shared = 1;
369         }
370
371         *p = new;
372
373         /* Exclude IRQ from balancing */
374         if (new->flags & IRQF_NOBALANCING)
375                 desc->status |= IRQ_NO_BALANCING;
376
377         if (!shared) {
378                 irq_chip_set_defaults(desc->chip);
379
380 #if defined(CONFIG_IRQ_PER_CPU)
381                 if (new->flags & IRQF_PERCPU)
382                         desc->status |= IRQ_PER_CPU;
383 #endif
384
385                 /* Setup the type (level, edge polarity) if configured: */
386                 if (new->flags & IRQF_TRIGGER_MASK) {
387                         if (desc->chip->set_type)
388                                 desc->chip->set_type(irq,
389                                                 new->flags & IRQF_TRIGGER_MASK);
390                         else
391                                 /*
392                                  * IRQF_TRIGGER_* but the PIC does not support
393                                  * multiple flow-types?
394                                  */
395                                 printk(KERN_WARNING "No IRQF_TRIGGER set_type "
396                                        "function for IRQ %d (%s)\n", irq,
397                                        desc->chip->name);
398                 } else
399                         compat_irq_chip_set_default_handler(desc);
400
401                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
402                                   IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
403
404                 if (!(desc->status & IRQ_NOAUTOEN)) {
405                         desc->depth = 0;
406                         desc->status &= ~IRQ_DISABLED;
407                         if (desc->chip->startup)
408                                 desc->chip->startup(irq);
409                         else
410                                 desc->chip->enable(irq);
411                 } else
412                         /* Undo nested disables: */
413                         desc->depth = 1;
414
415                 /* Set default affinity mask once everything is setup */
416                 irq_select_affinity(irq);
417         }
418         /* Reset broken irq detection when installing new handler */
419         desc->irq_count = 0;
420         desc->irqs_unhandled = 0;
421
422         /*
423          * Check whether we disabled the irq via the spurious handler
424          * before. Reenable it and give it another chance.
425          */
426         if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
427                 desc->status &= ~IRQ_SPURIOUS_DISABLED;
428                 __enable_irq(desc, irq);
429         }
430
431         spin_unlock_irqrestore(&desc->lock, flags);
432
433         new->irq = irq;
434         register_irq_proc(irq);
435         new->dir = NULL;
436         register_handler_proc(irq, new);
437
438         return 0;
439
440 mismatch:
441 #ifdef CONFIG_DEBUG_SHIRQ
442         if (!(new->flags & IRQF_PROBE_SHARED)) {
443                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
444                 if (old_name)
445                         printk(KERN_ERR "current handler: %s\n", old_name);
446                 dump_stack();
447         }
448 #endif
449         spin_unlock_irqrestore(&desc->lock, flags);
450         return -EBUSY;
451 }
452
453 /**
454  *      free_irq - free an interrupt
455  *      @irq: Interrupt line to free
456  *      @dev_id: Device identity to free
457  *
458  *      Remove an interrupt handler. The handler is removed and if the
459  *      interrupt line is no longer in use by any driver it is disabled.
460  *      On a shared IRQ the caller must ensure the interrupt is disabled
461  *      on the card it drives before calling this function. The function
462  *      does not return until any executing interrupts for this IRQ
463  *      have completed.
464  *
465  *      This function must not be called from interrupt context.
466  */
467 void free_irq(unsigned int irq, void *dev_id)
468 {
469         struct irq_desc *desc;
470         struct irqaction **p;
471         unsigned long flags;
472
473         WARN_ON(in_interrupt());
474         if (irq >= NR_IRQS)
475                 return;
476
477         desc = irq_desc + irq;
478         spin_lock_irqsave(&desc->lock, flags);
479         p = &desc->action;
480         for (;;) {
481                 struct irqaction *action = *p;
482
483                 if (action) {
484                         struct irqaction **pp = p;
485
486                         p = &action->next;
487                         if (action->dev_id != dev_id)
488                                 continue;
489
490                         /* Found it - now remove it from the list of entries */
491                         *pp = action->next;
492
493                         /* Currently used only by UML, might disappear one day.*/
494 #ifdef CONFIG_IRQ_RELEASE_METHOD
495                         if (desc->chip->release)
496                                 desc->chip->release(irq, dev_id);
497 #endif
498
499                         if (!desc->action) {
500                                 desc->status |= IRQ_DISABLED;
501                                 if (desc->chip->shutdown)
502                                         desc->chip->shutdown(irq);
503                                 else
504                                         desc->chip->disable(irq);
505                         }
506                         spin_unlock_irqrestore(&desc->lock, flags);
507                         unregister_handler_proc(irq, action);
508
509                         /* Make sure it's not being used on another CPU */
510                         synchronize_irq(irq);
511 #ifdef CONFIG_DEBUG_SHIRQ
512                         /*
513                          * It's a shared IRQ -- the driver ought to be
514                          * prepared for it to happen even now it's
515                          * being freed, so let's make sure....  We do
516                          * this after actually deregistering it, to
517                          * make sure that a 'real' IRQ doesn't run in
518                          * parallel with our fake
519                          */
520                         if (action->flags & IRQF_SHARED) {
521                                 local_irq_save(flags);
522                                 action->handler(irq, dev_id);
523                                 local_irq_restore(flags);
524                         }
525 #endif
526                         kfree(action);
527                         return;
528                 }
529                 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
530 #ifdef CONFIG_DEBUG_SHIRQ
531                 dump_stack();
532 #endif
533                 spin_unlock_irqrestore(&desc->lock, flags);
534                 return;
535         }
536 }
537 EXPORT_SYMBOL(free_irq);
538
539 /**
540  *      request_irq - allocate an interrupt line
541  *      @irq: Interrupt line to allocate
542  *      @handler: Function to be called when the IRQ occurs
543  *      @irqflags: Interrupt type flags
544  *      @devname: An ascii name for the claiming device
545  *      @dev_id: A cookie passed back to the handler function
546  *
547  *      This call allocates interrupt resources and enables the
548  *      interrupt line and IRQ handling. From the point this
549  *      call is made your handler function may be invoked. Since
550  *      your handler function must clear any interrupt the board
551  *      raises, you must take care both to initialise your hardware
552  *      and to set up the interrupt handler in the right order.
553  *
554  *      Dev_id must be globally unique. Normally the address of the
555  *      device data structure is used as the cookie. Since the handler
556  *      receives this value it makes sense to use it.
557  *
558  *      If your interrupt is shared you must pass a non NULL dev_id
559  *      as this is required when freeing the interrupt.
560  *
561  *      Flags:
562  *
563  *      IRQF_SHARED             Interrupt is shared
564  *      IRQF_DISABLED   Disable local interrupts while processing
565  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
566  *
567  */
568 int request_irq(unsigned int irq, irq_handler_t handler,
569                 unsigned long irqflags, const char *devname, void *dev_id)
570 {
571         struct irqaction *action;
572         int retval;
573
574 #ifdef CONFIG_LOCKDEP
575         /*
576          * Lockdep wants atomic interrupt handlers:
577          */
578         irqflags |= IRQF_DISABLED;
579 #endif
580         /*
581          * Sanity-check: shared interrupts must pass in a real dev-ID,
582          * otherwise we'll have trouble later trying to figure out
583          * which interrupt is which (messes up the interrupt freeing
584          * logic etc).
585          */
586         if ((irqflags & IRQF_SHARED) && !dev_id)
587                 return -EINVAL;
588         if (irq >= NR_IRQS)
589                 return -EINVAL;
590         if (irq_desc[irq].status & IRQ_NOREQUEST)
591                 return -EINVAL;
592         if (!handler)
593                 return -EINVAL;
594
595         action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
596         if (!action)
597                 return -ENOMEM;
598
599         action->handler = handler;
600         action->flags = irqflags;
601         cpus_clear(action->mask);
602         action->name = devname;
603         action->next = NULL;
604         action->dev_id = dev_id;
605
606 #ifdef CONFIG_DEBUG_SHIRQ
607         if (irqflags & IRQF_SHARED) {
608                 /*
609                  * It's a shared IRQ -- the driver ought to be prepared for it
610                  * to happen immediately, so let's make sure....
611                  * We do this before actually registering it, to make sure that
612                  * a 'real' IRQ doesn't run in parallel with our fake
613                  */
614                 unsigned long flags;
615
616                 local_irq_save(flags);
617                 handler(irq, dev_id);
618                 local_irq_restore(flags);
619         }
620 #endif
621
622         retval = setup_irq(irq, action);
623         if (retval)
624                 kfree(action);
625
626         return retval;
627 }
628 EXPORT_SYMBOL(request_irq);