801addda3c43d4a7a767b27468fee05232cb6f89
[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_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         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                 desc->affinity = cpumask;
95                 desc->chip->set_affinity(irq, cpumask);
96         } else {
97                 desc->status |= IRQ_MOVE_PENDING;
98                 desc->pending_mask = cpumask;
99         }
100 #else
101         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         cpumask_t mask;
116
117         if (!irq_can_set_affinity(irq))
118                 return 0;
119
120         cpus_and(mask, cpu_online_map, irq_default_affinity);
121
122         /*
123          * Preserve an userspace affinity setup, but make sure that
124          * one of the targets is online.
125          */
126         if (desc->status & (IRQ_AFFINITY_SET | IRQ_NO_BALANCING)) {
127                 if (cpus_intersects(desc->affinity, cpu_online_map))
128                         mask = desc->affinity;
129                 else
130                         desc->status &= ~IRQ_AFFINITY_SET;
131         }
132
133         desc->affinity = mask;
134         desc->chip->set_affinity(irq, mask);
135
136         return 0;
137 }
138 #else
139 static inline int do_irq_select_affinity(unsigned int irq, struct irq_desc *d)
140 {
141         return irq_select_affinity(irq);
142 }
143 #endif
144
145 /*
146  * Called when affinity is set via /proc/irq
147  */
148 int irq_select_affinity_usr(unsigned int irq)
149 {
150         struct irq_desc *desc = irq_to_desc(irq);
151         unsigned long flags;
152         int ret;
153
154         spin_lock_irqsave(&desc->lock, flags);
155         ret = do_irq_select_affinity(irq, desc);
156         spin_unlock_irqrestore(&desc->lock, flags);
157
158         return ret;
159 }
160
161 #else
162 static inline int do_irq_select_affinity(int irq, struct irq_desc *desc)
163 {
164         return 0;
165 }
166 #endif
167
168 /**
169  *      disable_irq_nosync - disable an irq without waiting
170  *      @irq: Interrupt to disable
171  *
172  *      Disable the selected interrupt line.  Disables and Enables are
173  *      nested.
174  *      Unlike disable_irq(), this function does not ensure existing
175  *      instances of the IRQ handler have completed before returning.
176  *
177  *      This function may be called from IRQ context.
178  */
179 void disable_irq_nosync(unsigned int irq)
180 {
181         struct irq_desc *desc = irq_to_desc(irq);
182         unsigned long flags;
183
184         if (!desc)
185                 return;
186
187         spin_lock_irqsave(&desc->lock, flags);
188         if (!desc->depth++) {
189                 desc->status |= IRQ_DISABLED;
190                 desc->chip->disable(irq);
191         }
192         spin_unlock_irqrestore(&desc->lock, flags);
193 }
194 EXPORT_SYMBOL(disable_irq_nosync);
195
196 /**
197  *      disable_irq - disable an irq and wait for completion
198  *      @irq: Interrupt to disable
199  *
200  *      Disable the selected interrupt line.  Enables and Disables are
201  *      nested.
202  *      This function waits for any pending IRQ handlers for this interrupt
203  *      to complete before returning. If you use this function while
204  *      holding a resource the IRQ handler may need you will deadlock.
205  *
206  *      This function may be called - with care - from IRQ context.
207  */
208 void disable_irq(unsigned int irq)
209 {
210         struct irq_desc *desc = irq_to_desc(irq);
211
212         if (!desc)
213                 return;
214
215         disable_irq_nosync(irq);
216         if (desc->action)
217                 synchronize_irq(irq);
218 }
219 EXPORT_SYMBOL(disable_irq);
220
221 static void __enable_irq(struct irq_desc *desc, unsigned int irq)
222 {
223         switch (desc->depth) {
224         case 0:
225                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
226                 break;
227         case 1: {
228                 unsigned int status = desc->status & ~IRQ_DISABLED;
229
230                 /* Prevent probing on this irq: */
231                 desc->status = status | IRQ_NOPROBE;
232                 check_irq_resend(desc, irq);
233                 /* fall-through */
234         }
235         default:
236                 desc->depth--;
237         }
238 }
239
240 /**
241  *      enable_irq - enable handling of an irq
242  *      @irq: Interrupt to enable
243  *
244  *      Undoes the effect of one call to disable_irq().  If this
245  *      matches the last disable, processing of interrupts on this
246  *      IRQ line is re-enabled.
247  *
248  *      This function may be called from IRQ context.
249  */
250 void enable_irq(unsigned int irq)
251 {
252         struct irq_desc *desc = irq_to_desc(irq);
253         unsigned long flags;
254
255         if (!desc)
256                 return;
257
258         spin_lock_irqsave(&desc->lock, flags);
259         __enable_irq(desc, irq);
260         spin_unlock_irqrestore(&desc->lock, flags);
261 }
262 EXPORT_SYMBOL(enable_irq);
263
264 static int set_irq_wake_real(unsigned int irq, unsigned int on)
265 {
266         struct irq_desc *desc = irq_to_desc(irq);
267         int ret = -ENXIO;
268
269         if (desc->chip->set_wake)
270                 ret = desc->chip->set_wake(irq, on);
271
272         return ret;
273 }
274
275 /**
276  *      set_irq_wake - control irq power management wakeup
277  *      @irq:   interrupt to control
278  *      @on:    enable/disable power management wakeup
279  *
280  *      Enable/disable power management wakeup mode, which is
281  *      disabled by default.  Enables and disables must match,
282  *      just as they match for non-wakeup mode support.
283  *
284  *      Wakeup mode lets this IRQ wake the system from sleep
285  *      states like "suspend to RAM".
286  */
287 int set_irq_wake(unsigned int irq, unsigned int on)
288 {
289         struct irq_desc *desc = irq_to_desc(irq);
290         unsigned long flags;
291         int ret = 0;
292
293         /* wakeup-capable irqs can be shared between drivers that
294          * don't need to have the same sleep mode behaviors.
295          */
296         spin_lock_irqsave(&desc->lock, flags);
297         if (on) {
298                 if (desc->wake_depth++ == 0) {
299                         ret = set_irq_wake_real(irq, on);
300                         if (ret)
301                                 desc->wake_depth = 0;
302                         else
303                                 desc->status |= IRQ_WAKEUP;
304                 }
305         } else {
306                 if (desc->wake_depth == 0) {
307                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
308                 } else if (--desc->wake_depth == 0) {
309                         ret = set_irq_wake_real(irq, on);
310                         if (ret)
311                                 desc->wake_depth = 1;
312                         else
313                                 desc->status &= ~IRQ_WAKEUP;
314                 }
315         }
316
317         spin_unlock_irqrestore(&desc->lock, flags);
318         return ret;
319 }
320 EXPORT_SYMBOL(set_irq_wake);
321
322 /*
323  * Internal function that tells the architecture code whether a
324  * particular irq has been exclusively allocated or is available
325  * for driver use.
326  */
327 int can_request_irq(unsigned int irq, unsigned long irqflags)
328 {
329         struct irq_desc *desc = irq_to_desc(irq);
330         struct irqaction *action;
331
332         if (!desc)
333                 return 0;
334
335         if (desc->status & IRQ_NOREQUEST)
336                 return 0;
337
338         action = desc->action;
339         if (action)
340                 if (irqflags & action->flags & IRQF_SHARED)
341                         action = NULL;
342
343         return !action;
344 }
345
346 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
347 {
348         /*
349          * If the architecture still has not overriden
350          * the flow handler then zap the default. This
351          * should catch incorrect flow-type setting.
352          */
353         if (desc->handle_irq == &handle_bad_irq)
354                 desc->handle_irq = NULL;
355 }
356
357 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
358                 unsigned long flags)
359 {
360         int ret;
361         struct irq_chip *chip = desc->chip;
362
363         if (!chip || !chip->set_type) {
364                 /*
365                  * IRQF_TRIGGER_* but the PIC does not support multiple
366                  * flow-types?
367                  */
368                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
369                                 chip ? (chip->name ? : "unknown") : "unknown");
370                 return 0;
371         }
372
373         ret = chip->set_type(irq, flags & IRQF_TRIGGER_MASK);
374
375         if (ret)
376                 pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
377                                 (int)(flags & IRQF_TRIGGER_MASK),
378                                 irq, chip->set_type);
379         else {
380                 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
381                 desc->status &= ~IRQ_TYPE_SENSE_MASK;
382                 desc->status |= flags & IRQ_TYPE_SENSE_MASK;
383         }
384
385         return ret;
386 }
387
388 /*
389  * Internal function to register an irqaction - typically used to
390  * allocate special interrupts that are part of the architecture.
391  */
392 static int
393 __setup_irq(unsigned int irq, struct irq_desc * desc, struct irqaction *new)
394 {
395         struct irqaction *old, **p;
396         const char *old_name = NULL;
397         unsigned long flags;
398         int shared = 0;
399         int ret;
400
401         if (!desc)
402                 return -EINVAL;
403
404         if (desc->chip == &no_irq_chip)
405                 return -ENOSYS;
406         /*
407          * Some drivers like serial.c use request_irq() heavily,
408          * so we have to be careful not to interfere with a
409          * running system.
410          */
411         if (new->flags & IRQF_SAMPLE_RANDOM) {
412                 /*
413                  * This function might sleep, we want to call it first,
414                  * outside of the atomic block.
415                  * Yes, this might clear the entropy pool if the wrong
416                  * driver is attempted to be loaded, without actually
417                  * installing a new handler, but is this really a problem,
418                  * only the sysadmin is able to do this.
419                  */
420                 rand_initialize_irq(irq);
421         }
422
423         /*
424          * The following block of code has to be executed atomically
425          */
426         spin_lock_irqsave(&desc->lock, flags);
427         p = &desc->action;
428         old = *p;
429         if (old) {
430                 /*
431                  * Can't share interrupts unless both agree to and are
432                  * the same type (level, edge, polarity). So both flag
433                  * fields must have IRQF_SHARED set and the bits which
434                  * set the trigger type must match.
435                  */
436                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
437                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
438                         old_name = old->name;
439                         goto mismatch;
440                 }
441
442 #if defined(CONFIG_IRQ_PER_CPU)
443                 /* All handlers must agree on per-cpuness */
444                 if ((old->flags & IRQF_PERCPU) !=
445                     (new->flags & IRQF_PERCPU))
446                         goto mismatch;
447 #endif
448
449                 /* add new interrupt at end of irq queue */
450                 do {
451                         p = &old->next;
452                         old = *p;
453                 } while (old);
454                 shared = 1;
455         }
456
457         if (!shared) {
458                 irq_chip_set_defaults(desc->chip);
459
460                 /* Setup the type (level, edge polarity) if configured: */
461                 if (new->flags & IRQF_TRIGGER_MASK) {
462                         ret = __irq_set_trigger(desc, irq, new->flags);
463
464                         if (ret) {
465                                 spin_unlock_irqrestore(&desc->lock, flags);
466                                 return ret;
467                         }
468                 } else
469                         compat_irq_chip_set_default_handler(desc);
470 #if defined(CONFIG_IRQ_PER_CPU)
471                 if (new->flags & IRQF_PERCPU)
472                         desc->status |= IRQ_PER_CPU;
473 #endif
474
475                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
476                                   IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
477
478                 if (!(desc->status & IRQ_NOAUTOEN)) {
479                         desc->depth = 0;
480                         desc->status &= ~IRQ_DISABLED;
481                         desc->chip->startup(irq);
482                 } else
483                         /* Undo nested disables: */
484                         desc->depth = 1;
485
486                 /* Exclude IRQ from balancing if requested */
487                 if (new->flags & IRQF_NOBALANCING)
488                         desc->status |= IRQ_NO_BALANCING;
489
490                 /* Set default affinity mask once everything is setup */
491                 do_irq_select_affinity(irq, desc);
492
493         } else if ((new->flags & IRQF_TRIGGER_MASK)
494                         && (new->flags & IRQF_TRIGGER_MASK)
495                                 != (desc->status & IRQ_TYPE_SENSE_MASK)) {
496                 /* hope the handler works with the actual trigger mode... */
497                 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
498                                 irq, (int)(desc->status & IRQ_TYPE_SENSE_MASK),
499                                 (int)(new->flags & IRQF_TRIGGER_MASK));
500         }
501
502         *p = new;
503
504         /* Reset broken irq detection when installing new handler */
505         desc->irq_count = 0;
506         desc->irqs_unhandled = 0;
507
508         /*
509          * Check whether we disabled the irq via the spurious handler
510          * before. Reenable it and give it another chance.
511          */
512         if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
513                 desc->status &= ~IRQ_SPURIOUS_DISABLED;
514                 __enable_irq(desc, irq);
515         }
516
517         spin_unlock_irqrestore(&desc->lock, flags);
518
519         new->irq = irq;
520         register_irq_proc(irq, desc);
521         new->dir = NULL;
522         register_handler_proc(irq, new);
523
524         return 0;
525
526 mismatch:
527 #ifdef CONFIG_DEBUG_SHIRQ
528         if (!(new->flags & IRQF_PROBE_SHARED)) {
529                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
530                 if (old_name)
531                         printk(KERN_ERR "current handler: %s\n", old_name);
532                 dump_stack();
533         }
534 #endif
535         spin_unlock_irqrestore(&desc->lock, flags);
536         return -EBUSY;
537 }
538
539 /**
540  *      setup_irq - setup an interrupt
541  *      @irq: Interrupt line to setup
542  *      @act: irqaction for the interrupt
543  *
544  * Used to statically setup interrupts in the early boot process.
545  */
546 int setup_irq(unsigned int irq, struct irqaction *act)
547 {
548         struct irq_desc *desc = irq_to_desc(irq);
549
550         return __setup_irq(irq, desc, act);
551 }
552
553 /**
554  *      free_irq - free an interrupt
555  *      @irq: Interrupt line to free
556  *      @dev_id: Device identity to free
557  *
558  *      Remove an interrupt handler. The handler is removed and if the
559  *      interrupt line is no longer in use by any driver it is disabled.
560  *      On a shared IRQ the caller must ensure the interrupt is disabled
561  *      on the card it drives before calling this function. The function
562  *      does not return until any executing interrupts for this IRQ
563  *      have completed.
564  *
565  *      This function must not be called from interrupt context.
566  */
567 void free_irq(unsigned int irq, void *dev_id)
568 {
569         struct irq_desc *desc = irq_to_desc(irq);
570         struct irqaction **p;
571         unsigned long flags;
572
573         WARN_ON(in_interrupt());
574
575         if (!desc)
576                 return;
577
578         spin_lock_irqsave(&desc->lock, flags);
579         p = &desc->action;
580         for (;;) {
581                 struct irqaction *action = *p;
582
583                 if (action) {
584                         struct irqaction **pp = p;
585
586                         p = &action->next;
587                         if (action->dev_id != dev_id)
588                                 continue;
589
590                         /* Found it - now remove it from the list of entries */
591                         *pp = action->next;
592
593                         /* Currently used only by UML, might disappear one day.*/
594 #ifdef CONFIG_IRQ_RELEASE_METHOD
595                         if (desc->chip->release)
596                                 desc->chip->release(irq, dev_id);
597 #endif
598
599                         if (!desc->action) {
600                                 desc->status |= IRQ_DISABLED;
601                                 if (desc->chip->shutdown)
602                                         desc->chip->shutdown(irq);
603                                 else
604                                         desc->chip->disable(irq);
605                         }
606                         spin_unlock_irqrestore(&desc->lock, flags);
607                         unregister_handler_proc(irq, action);
608
609                         /* Make sure it's not being used on another CPU */
610                         synchronize_irq(irq);
611 #ifdef CONFIG_DEBUG_SHIRQ
612                         /*
613                          * It's a shared IRQ -- the driver ought to be
614                          * prepared for it to happen even now it's
615                          * being freed, so let's make sure....  We do
616                          * this after actually deregistering it, to
617                          * make sure that a 'real' IRQ doesn't run in
618                          * parallel with our fake
619                          */
620                         if (action->flags & IRQF_SHARED) {
621                                 local_irq_save(flags);
622                                 action->handler(irq, dev_id);
623                                 local_irq_restore(flags);
624                         }
625 #endif
626                         kfree(action);
627                         return;
628                 }
629                 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
630 #ifdef CONFIG_DEBUG_SHIRQ
631                 dump_stack();
632 #endif
633                 spin_unlock_irqrestore(&desc->lock, flags);
634                 return;
635         }
636 }
637 EXPORT_SYMBOL(free_irq);
638
639 /**
640  *      request_irq - allocate an interrupt line
641  *      @irq: Interrupt line to allocate
642  *      @handler: Function to be called when the IRQ occurs
643  *      @irqflags: Interrupt type flags
644  *      @devname: An ascii name for the claiming device
645  *      @dev_id: A cookie passed back to the handler function
646  *
647  *      This call allocates interrupt resources and enables the
648  *      interrupt line and IRQ handling. From the point this
649  *      call is made your handler function may be invoked. Since
650  *      your handler function must clear any interrupt the board
651  *      raises, you must take care both to initialise your hardware
652  *      and to set up the interrupt handler in the right order.
653  *
654  *      Dev_id must be globally unique. Normally the address of the
655  *      device data structure is used as the cookie. Since the handler
656  *      receives this value it makes sense to use it.
657  *
658  *      If your interrupt is shared you must pass a non NULL dev_id
659  *      as this is required when freeing the interrupt.
660  *
661  *      Flags:
662  *
663  *      IRQF_SHARED             Interrupt is shared
664  *      IRQF_DISABLED   Disable local interrupts while processing
665  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
666  *      IRQF_TRIGGER_*          Specify active edge(s) or level
667  *
668  */
669 int request_irq(unsigned int irq, irq_handler_t handler,
670                 unsigned long irqflags, const char *devname, void *dev_id)
671 {
672         struct irqaction *action;
673         struct irq_desc *desc;
674         int retval;
675
676 #ifdef CONFIG_LOCKDEP
677         /*
678          * Lockdep wants atomic interrupt handlers:
679          */
680         irqflags |= IRQF_DISABLED;
681 #endif
682         /*
683          * Sanity-check: shared interrupts must pass in a real dev-ID,
684          * otherwise we'll have trouble later trying to figure out
685          * which interrupt is which (messes up the interrupt freeing
686          * logic etc).
687          */
688         if ((irqflags & IRQF_SHARED) && !dev_id)
689                 return -EINVAL;
690
691         desc = irq_to_desc(irq);
692         if (!desc)
693                 return -EINVAL;
694
695         if (desc->status & IRQ_NOREQUEST)
696                 return -EINVAL;
697         if (!handler)
698                 return -EINVAL;
699
700         action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
701         if (!action)
702                 return -ENOMEM;
703
704         action->handler = handler;
705         action->flags = irqflags;
706         cpus_clear(action->mask);
707         action->name = devname;
708         action->next = NULL;
709         action->dev_id = dev_id;
710
711         retval = __setup_irq(irq, desc, action);
712         if (retval)
713                 kfree(action);
714
715 #ifdef CONFIG_DEBUG_SHIRQ
716         if (irqflags & IRQF_SHARED) {
717                 /*
718                  * It's a shared IRQ -- the driver ought to be prepared for it
719                  * to happen immediately, so let's make sure....
720                  * We disable the irq to make sure that a 'real' IRQ doesn't
721                  * run in parallel with our fake.
722                  */
723                 unsigned long flags;
724
725                 disable_irq(irq);
726                 local_irq_save(flags);
727
728                 handler(irq, dev_id);
729
730                 local_irq_restore(flags);
731                 enable_irq(irq);
732         }
733 #endif
734         return retval;
735 }
736 EXPORT_SYMBOL(request_irq);