Merge git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc
[linux-2.6] / kernel / irq / manage.c
1 /*
2  * linux/kernel/irq/manage.c
3  *
4  * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
5  * Copyright (C) 2005-2006 Thomas Gleixner
6  *
7  * This file contains driver APIs to the irq subsystem.
8  */
9
10 #include <linux/irq.h>
11 #include <linux/module.h>
12 #include <linux/random.h>
13 #include <linux/interrupt.h>
14
15 #include "internals.h"
16
17 #ifdef CONFIG_SMP
18
19 /**
20  *      synchronize_irq - wait for pending IRQ handlers (on other CPUs)
21  *      @irq: interrupt number to wait for
22  *
23  *      This function waits for any pending IRQ handlers for this interrupt
24  *      to complete before returning. If you use this function while
25  *      holding a resource the IRQ handler may need you will deadlock.
26  *
27  *      This function may be called - with care - from IRQ context.
28  */
29 void synchronize_irq(unsigned int irq)
30 {
31         struct irq_desc *desc = irq_desc + irq;
32
33         if (irq >= NR_IRQS)
34                 return;
35
36         while (desc->status & IRQ_INPROGRESS)
37                 cpu_relax();
38 }
39 EXPORT_SYMBOL(synchronize_irq);
40
41 /**
42  *      irq_can_set_affinity - Check if the affinity of a given irq can be set
43  *      @irq:           Interrupt to check
44  *
45  */
46 int irq_can_set_affinity(unsigned int irq)
47 {
48         struct irq_desc *desc = irq_desc + irq;
49
50         if (CHECK_IRQ_PER_CPU(desc->status) || !desc->chip ||
51             !desc->chip->set_affinity)
52                 return 0;
53
54         return 1;
55 }
56
57 /**
58  *      irq_set_affinity - Set the irq affinity of a given irq
59  *      @irq:           Interrupt to set affinity
60  *      @cpumask:       cpumask
61  *
62  */
63 int irq_set_affinity(unsigned int irq, cpumask_t cpumask)
64 {
65         struct irq_desc *desc = irq_desc + irq;
66
67         if (!desc->chip->set_affinity)
68                 return -EINVAL;
69
70         set_balance_irq_affinity(irq, cpumask);
71
72 #ifdef CONFIG_GENERIC_PENDING_IRQ
73         set_pending_irq(irq, cpumask);
74 #else
75         desc->affinity = cpumask;
76         desc->chip->set_affinity(irq, cpumask);
77 #endif
78         return 0;
79 }
80
81 #endif
82
83 /**
84  *      disable_irq_nosync - disable an irq without waiting
85  *      @irq: Interrupt to disable
86  *
87  *      Disable the selected interrupt line.  Disables and Enables are
88  *      nested.
89  *      Unlike disable_irq(), this function does not ensure existing
90  *      instances of the IRQ handler have completed before returning.
91  *
92  *      This function may be called from IRQ context.
93  */
94 void disable_irq_nosync(unsigned int irq)
95 {
96         struct irq_desc *desc = irq_desc + irq;
97         unsigned long flags;
98
99         if (irq >= NR_IRQS)
100                 return;
101
102         spin_lock_irqsave(&desc->lock, flags);
103         if (!desc->depth++) {
104                 desc->status |= IRQ_DISABLED;
105                 desc->chip->disable(irq);
106         }
107         spin_unlock_irqrestore(&desc->lock, flags);
108 }
109 EXPORT_SYMBOL(disable_irq_nosync);
110
111 /**
112  *      disable_irq - disable an irq and wait for completion
113  *      @irq: Interrupt to disable
114  *
115  *      Disable the selected interrupt line.  Enables and Disables are
116  *      nested.
117  *      This function waits for any pending IRQ handlers for this interrupt
118  *      to complete before returning. If you use this function while
119  *      holding a resource the IRQ handler may need you will deadlock.
120  *
121  *      This function may be called - with care - from IRQ context.
122  */
123 void disable_irq(unsigned int irq)
124 {
125         struct irq_desc *desc = irq_desc + irq;
126
127         if (irq >= NR_IRQS)
128                 return;
129
130         disable_irq_nosync(irq);
131         if (desc->action)
132                 synchronize_irq(irq);
133 }
134 EXPORT_SYMBOL(disable_irq);
135
136 /**
137  *      enable_irq - enable handling of an irq
138  *      @irq: Interrupt to enable
139  *
140  *      Undoes the effect of one call to disable_irq().  If this
141  *      matches the last disable, processing of interrupts on this
142  *      IRQ line is re-enabled.
143  *
144  *      This function may be called from IRQ context.
145  */
146 void enable_irq(unsigned int irq)
147 {
148         struct irq_desc *desc = irq_desc + irq;
149         unsigned long flags;
150
151         if (irq >= NR_IRQS)
152                 return;
153
154         spin_lock_irqsave(&desc->lock, flags);
155         switch (desc->depth) {
156         case 0:
157                 printk(KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
158                 WARN_ON(1);
159                 break;
160         case 1: {
161                 unsigned int status = desc->status & ~IRQ_DISABLED;
162
163                 /* Prevent probing on this irq: */
164                 desc->status = status | IRQ_NOPROBE;
165                 check_irq_resend(desc, irq);
166                 /* fall-through */
167         }
168         default:
169                 desc->depth--;
170         }
171         spin_unlock_irqrestore(&desc->lock, flags);
172 }
173 EXPORT_SYMBOL(enable_irq);
174
175 /**
176  *      set_irq_wake - control irq power management wakeup
177  *      @irq:   interrupt to control
178  *      @on:    enable/disable power management wakeup
179  *
180  *      Enable/disable power management wakeup mode, which is
181  *      disabled by default.  Enables and disables must match,
182  *      just as they match for non-wakeup mode support.
183  *
184  *      Wakeup mode lets this IRQ wake the system from sleep
185  *      states like "suspend to RAM".
186  */
187 int set_irq_wake(unsigned int irq, unsigned int on)
188 {
189         struct irq_desc *desc = irq_desc + irq;
190         unsigned long flags;
191         int ret = -ENXIO;
192         int (*set_wake)(unsigned, unsigned) = desc->chip->set_wake;
193
194         /* wakeup-capable irqs can be shared between drivers that
195          * don't need to have the same sleep mode behaviors.
196          */
197         spin_lock_irqsave(&desc->lock, flags);
198         if (on) {
199                 if (desc->wake_depth++ == 0)
200                         desc->status |= IRQ_WAKEUP;
201                 else
202                         set_wake = NULL;
203         } else {
204                 if (desc->wake_depth == 0) {
205                         printk(KERN_WARNING "Unbalanced IRQ %d "
206                                         "wake disable\n", irq);
207                         WARN_ON(1);
208                 } else if (--desc->wake_depth == 0)
209                         desc->status &= ~IRQ_WAKEUP;
210                 else
211                         set_wake = NULL;
212         }
213         if (set_wake)
214                 ret = desc->chip->set_wake(irq, on);
215         spin_unlock_irqrestore(&desc->lock, flags);
216         return ret;
217 }
218 EXPORT_SYMBOL(set_irq_wake);
219
220 /*
221  * Internal function that tells the architecture code whether a
222  * particular irq has been exclusively allocated or is available
223  * for driver use.
224  */
225 int can_request_irq(unsigned int irq, unsigned long irqflags)
226 {
227         struct irqaction *action;
228
229         if (irq >= NR_IRQS || irq_desc[irq].status & IRQ_NOREQUEST)
230                 return 0;
231
232         action = irq_desc[irq].action;
233         if (action)
234                 if (irqflags & action->flags & IRQF_SHARED)
235                         action = NULL;
236
237         return !action;
238 }
239
240 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
241 {
242         /*
243          * If the architecture still has not overriden
244          * the flow handler then zap the default. This
245          * should catch incorrect flow-type setting.
246          */
247         if (desc->handle_irq == &handle_bad_irq)
248                 desc->handle_irq = NULL;
249 }
250
251 /*
252  * Internal function to register an irqaction - typically used to
253  * allocate special interrupts that are part of the architecture.
254  */
255 int setup_irq(unsigned int irq, struct irqaction *new)
256 {
257         struct irq_desc *desc = irq_desc + irq;
258         struct irqaction *old, **p;
259         const char *old_name = NULL;
260         unsigned long flags;
261         int shared = 0;
262
263         if (irq >= NR_IRQS)
264                 return -EINVAL;
265
266         if (desc->chip == &no_irq_chip)
267                 return -ENOSYS;
268         /*
269          * Some drivers like serial.c use request_irq() heavily,
270          * so we have to be careful not to interfere with a
271          * running system.
272          */
273         if (new->flags & IRQF_SAMPLE_RANDOM) {
274                 /*
275                  * This function might sleep, we want to call it first,
276                  * outside of the atomic block.
277                  * Yes, this might clear the entropy pool if the wrong
278                  * driver is attempted to be loaded, without actually
279                  * installing a new handler, but is this really a problem,
280                  * only the sysadmin is able to do this.
281                  */
282                 rand_initialize_irq(irq);
283         }
284
285         /*
286          * The following block of code has to be executed atomically
287          */
288         spin_lock_irqsave(&desc->lock, flags);
289         p = &desc->action;
290         old = *p;
291         if (old) {
292                 /*
293                  * Can't share interrupts unless both agree to and are
294                  * the same type (level, edge, polarity). So both flag
295                  * fields must have IRQF_SHARED set and the bits which
296                  * set the trigger type must match.
297                  */
298                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
299                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
300                         old_name = old->name;
301                         goto mismatch;
302                 }
303
304 #if defined(CONFIG_IRQ_PER_CPU)
305                 /* All handlers must agree on per-cpuness */
306                 if ((old->flags & IRQF_PERCPU) !=
307                     (new->flags & IRQF_PERCPU))
308                         goto mismatch;
309 #endif
310
311                 /* add new interrupt at end of irq queue */
312                 do {
313                         p = &old->next;
314                         old = *p;
315                 } while (old);
316                 shared = 1;
317         }
318
319         *p = new;
320 #if defined(CONFIG_IRQ_PER_CPU)
321         if (new->flags & IRQF_PERCPU)
322                 desc->status |= IRQ_PER_CPU;
323 #endif
324         /* Exclude IRQ from balancing */
325         if (new->flags & IRQF_NOBALANCING)
326                 desc->status |= IRQ_NO_BALANCING;
327
328         if (!shared) {
329                 irq_chip_set_defaults(desc->chip);
330
331                 /* Setup the type (level, edge polarity) if configured: */
332                 if (new->flags & IRQF_TRIGGER_MASK) {
333                         if (desc->chip && desc->chip->set_type)
334                                 desc->chip->set_type(irq,
335                                                 new->flags & IRQF_TRIGGER_MASK);
336                         else
337                                 /*
338                                  * IRQF_TRIGGER_* but the PIC does not support
339                                  * multiple flow-types?
340                                  */
341                                 printk(KERN_WARNING "No IRQF_TRIGGER set_type "
342                                        "function for IRQ %d (%s)\n", irq,
343                                        desc->chip ? desc->chip->name :
344                                        "unknown");
345                 } else
346                         compat_irq_chip_set_default_handler(desc);
347
348                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
349                                   IRQ_INPROGRESS);
350
351                 if (!(desc->status & IRQ_NOAUTOEN)) {
352                         desc->depth = 0;
353                         desc->status &= ~IRQ_DISABLED;
354                         if (desc->chip->startup)
355                                 desc->chip->startup(irq);
356                         else
357                                 desc->chip->enable(irq);
358                 } else
359                         /* Undo nested disables: */
360                         desc->depth = 1;
361         }
362         /* Reset broken irq detection when installing new handler */
363         desc->irq_count = 0;
364         desc->irqs_unhandled = 0;
365         spin_unlock_irqrestore(&desc->lock, flags);
366
367         new->irq = irq;
368         register_irq_proc(irq);
369         new->dir = NULL;
370         register_handler_proc(irq, new);
371
372         return 0;
373
374 mismatch:
375 #ifdef CONFIG_DEBUG_SHIRQ
376         if (!(new->flags & IRQF_PROBE_SHARED)) {
377                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
378                 if (old_name)
379                         printk(KERN_ERR "current handler: %s\n", old_name);
380                 dump_stack();
381         }
382 #endif
383         spin_unlock_irqrestore(&desc->lock, flags);
384         return -EBUSY;
385 }
386
387 /**
388  *      free_irq - free an interrupt
389  *      @irq: Interrupt line to free
390  *      @dev_id: Device identity to free
391  *
392  *      Remove an interrupt handler. The handler is removed and if the
393  *      interrupt line is no longer in use by any driver it is disabled.
394  *      On a shared IRQ the caller must ensure the interrupt is disabled
395  *      on the card it drives before calling this function. The function
396  *      does not return until any executing interrupts for this IRQ
397  *      have completed.
398  *
399  *      This function must not be called from interrupt context.
400  */
401 void free_irq(unsigned int irq, void *dev_id)
402 {
403         struct irq_desc *desc;
404         struct irqaction **p;
405         unsigned long flags;
406         irqreturn_t (*handler)(int, void *) = NULL;
407
408         WARN_ON(in_interrupt());
409         if (irq >= NR_IRQS)
410                 return;
411
412         desc = irq_desc + irq;
413         spin_lock_irqsave(&desc->lock, flags);
414         p = &desc->action;
415         for (;;) {
416                 struct irqaction *action = *p;
417
418                 if (action) {
419                         struct irqaction **pp = p;
420
421                         p = &action->next;
422                         if (action->dev_id != dev_id)
423                                 continue;
424
425                         /* Found it - now remove it from the list of entries */
426                         *pp = action->next;
427
428                         /* Currently used only by UML, might disappear one day.*/
429 #ifdef CONFIG_IRQ_RELEASE_METHOD
430                         if (desc->chip->release)
431                                 desc->chip->release(irq, dev_id);
432 #endif
433
434                         if (!desc->action) {
435                                 desc->status |= IRQ_DISABLED;
436                                 if (desc->chip->shutdown)
437                                         desc->chip->shutdown(irq);
438                                 else
439                                         desc->chip->disable(irq);
440                         }
441                         spin_unlock_irqrestore(&desc->lock, flags);
442                         unregister_handler_proc(irq, action);
443
444                         /* Make sure it's not being used on another CPU */
445                         synchronize_irq(irq);
446                         if (action->flags & IRQF_SHARED)
447                                 handler = action->handler;
448                         kfree(action);
449                         return;
450                 }
451                 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
452                 spin_unlock_irqrestore(&desc->lock, flags);
453                 return;
454         }
455 #ifdef CONFIG_DEBUG_SHIRQ
456         if (handler) {
457                 /*
458                  * It's a shared IRQ -- the driver ought to be prepared for it
459                  * to happen even now it's being freed, so let's make sure....
460                  * We do this after actually deregistering it, to make sure that
461                  * a 'real' IRQ doesn't run in parallel with our fake
462                  */
463                 handler(irq, dev_id);
464         }
465 #endif
466 }
467 EXPORT_SYMBOL(free_irq);
468
469 /**
470  *      request_irq - allocate an interrupt line
471  *      @irq: Interrupt line to allocate
472  *      @handler: Function to be called when the IRQ occurs
473  *      @irqflags: Interrupt type flags
474  *      @devname: An ascii name for the claiming device
475  *      @dev_id: A cookie passed back to the handler function
476  *
477  *      This call allocates interrupt resources and enables the
478  *      interrupt line and IRQ handling. From the point this
479  *      call is made your handler function may be invoked. Since
480  *      your handler function must clear any interrupt the board
481  *      raises, you must take care both to initialise your hardware
482  *      and to set up the interrupt handler in the right order.
483  *
484  *      Dev_id must be globally unique. Normally the address of the
485  *      device data structure is used as the cookie. Since the handler
486  *      receives this value it makes sense to use it.
487  *
488  *      If your interrupt is shared you must pass a non NULL dev_id
489  *      as this is required when freeing the interrupt.
490  *
491  *      Flags:
492  *
493  *      IRQF_SHARED             Interrupt is shared
494  *      IRQF_DISABLED   Disable local interrupts while processing
495  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
496  *
497  */
498 int request_irq(unsigned int irq, irq_handler_t handler,
499                 unsigned long irqflags, const char *devname, void *dev_id)
500 {
501         struct irqaction *action;
502         int retval;
503
504 #ifdef CONFIG_LOCKDEP
505         /*
506          * Lockdep wants atomic interrupt handlers:
507          */
508         irqflags |= IRQF_DISABLED;
509 #endif
510         /*
511          * Sanity-check: shared interrupts must pass in a real dev-ID,
512          * otherwise we'll have trouble later trying to figure out
513          * which interrupt is which (messes up the interrupt freeing
514          * logic etc).
515          */
516         if ((irqflags & IRQF_SHARED) && !dev_id)
517                 return -EINVAL;
518         if (irq >= NR_IRQS)
519                 return -EINVAL;
520         if (irq_desc[irq].status & IRQ_NOREQUEST)
521                 return -EINVAL;
522         if (!handler)
523                 return -EINVAL;
524
525         action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
526         if (!action)
527                 return -ENOMEM;
528
529         action->handler = handler;
530         action->flags = irqflags;
531         cpus_clear(action->mask);
532         action->name = devname;
533         action->next = NULL;
534         action->dev_id = dev_id;
535
536         select_smp_affinity(irq);
537
538 #ifdef CONFIG_DEBUG_SHIRQ
539         if (irqflags & IRQF_SHARED) {
540                 /*
541                  * It's a shared IRQ -- the driver ought to be prepared for it
542                  * to happen immediately, so let's make sure....
543                  * We do this before actually registering it, to make sure that
544                  * a 'real' IRQ doesn't run in parallel with our fake
545                  */
546                 if (irqflags & IRQF_DISABLED) {
547                         unsigned long flags;
548
549                         local_irq_save(flags);
550                         handler(irq, dev_id);
551                         local_irq_restore(flags);
552                 } else
553                         handler(irq, dev_id);
554         }
555 #endif
556
557         retval = setup_irq(irq, action);
558         if (retval)
559                 kfree(action);
560
561         return retval;
562 }
563 EXPORT_SYMBOL(request_irq);