genirq: Convert irq_desc.lock to raw_spinlock
[linux-3.10.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/kthread.h>
12 #include <linux/module.h>
13 #include <linux/random.h>
14 #include <linux/interrupt.h>
15 #include <linux/slab.h>
16 #include <linux/sched.h>
17
18 #include "internals.h"
19
20 /**
21  *      synchronize_irq - wait for pending IRQ handlers (on other CPUs)
22  *      @irq: interrupt number to wait for
23  *
24  *      This function waits for any pending IRQ handlers for this interrupt
25  *      to complete before returning. If you use this function while
26  *      holding a resource the IRQ handler may need you will deadlock.
27  *
28  *      This function may be called - with care - from IRQ context.
29  */
30 void synchronize_irq(unsigned int irq)
31 {
32         struct irq_desc *desc = irq_to_desc(irq);
33         unsigned int status;
34
35         if (!desc)
36                 return;
37
38         do {
39                 unsigned long flags;
40
41                 /*
42                  * Wait until we're out of the critical section.  This might
43                  * give the wrong answer due to the lack of memory barriers.
44                  */
45                 while (desc->status & IRQ_INPROGRESS)
46                         cpu_relax();
47
48                 /* Ok, that indicated we're done: double-check carefully. */
49                 raw_spin_lock_irqsave(&desc->lock, flags);
50                 status = desc->status;
51                 raw_spin_unlock_irqrestore(&desc->lock, flags);
52
53                 /* Oops, that failed? */
54         } while (status & IRQ_INPROGRESS);
55
56         /*
57          * We made sure that no hardirq handler is running. Now verify
58          * that no threaded handlers are active.
59          */
60         wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
61 }
62 EXPORT_SYMBOL(synchronize_irq);
63
64 #ifdef CONFIG_SMP
65 cpumask_var_t irq_default_affinity;
66
67 /**
68  *      irq_can_set_affinity - Check if the affinity of a given irq can be set
69  *      @irq:           Interrupt to check
70  *
71  */
72 int irq_can_set_affinity(unsigned int irq)
73 {
74         struct irq_desc *desc = irq_to_desc(irq);
75
76         if (CHECK_IRQ_PER_CPU(desc->status) || !desc->chip ||
77             !desc->chip->set_affinity)
78                 return 0;
79
80         return 1;
81 }
82
83 /**
84  *      irq_set_thread_affinity - Notify irq threads to adjust affinity
85  *      @desc:          irq descriptor which has affitnity changed
86  *
87  *      We just set IRQTF_AFFINITY and delegate the affinity setting
88  *      to the interrupt thread itself. We can not call
89  *      set_cpus_allowed_ptr() here as we hold desc->lock and this
90  *      code can be called from hard interrupt context.
91  */
92 void irq_set_thread_affinity(struct irq_desc *desc)
93 {
94         struct irqaction *action = desc->action;
95
96         while (action) {
97                 if (action->thread)
98                         set_bit(IRQTF_AFFINITY, &action->thread_flags);
99                 action = action->next;
100         }
101 }
102
103 /**
104  *      irq_set_affinity - Set the irq affinity of a given irq
105  *      @irq:           Interrupt to set affinity
106  *      @cpumask:       cpumask
107  *
108  */
109 int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
110 {
111         struct irq_desc *desc = irq_to_desc(irq);
112         unsigned long flags;
113
114         if (!desc->chip->set_affinity)
115                 return -EINVAL;
116
117         raw_spin_lock_irqsave(&desc->lock, flags);
118
119 #ifdef CONFIG_GENERIC_PENDING_IRQ
120         if (desc->status & IRQ_MOVE_PCNTXT) {
121                 if (!desc->chip->set_affinity(irq, cpumask)) {
122                         cpumask_copy(desc->affinity, cpumask);
123                         irq_set_thread_affinity(desc);
124                 }
125         }
126         else {
127                 desc->status |= IRQ_MOVE_PENDING;
128                 cpumask_copy(desc->pending_mask, cpumask);
129         }
130 #else
131         if (!desc->chip->set_affinity(irq, cpumask)) {
132                 cpumask_copy(desc->affinity, cpumask);
133                 irq_set_thread_affinity(desc);
134         }
135 #endif
136         desc->status |= IRQ_AFFINITY_SET;
137         raw_spin_unlock_irqrestore(&desc->lock, flags);
138         return 0;
139 }
140
141 #ifndef CONFIG_AUTO_IRQ_AFFINITY
142 /*
143  * Generic version of the affinity autoselector.
144  */
145 static int setup_affinity(unsigned int irq, struct irq_desc *desc)
146 {
147         if (!irq_can_set_affinity(irq))
148                 return 0;
149
150         /*
151          * Preserve an userspace affinity setup, but make sure that
152          * one of the targets is online.
153          */
154         if (desc->status & (IRQ_AFFINITY_SET | IRQ_NO_BALANCING)) {
155                 if (cpumask_any_and(desc->affinity, cpu_online_mask)
156                     < nr_cpu_ids)
157                         goto set_affinity;
158                 else
159                         desc->status &= ~IRQ_AFFINITY_SET;
160         }
161
162         cpumask_and(desc->affinity, cpu_online_mask, irq_default_affinity);
163 set_affinity:
164         desc->chip->set_affinity(irq, desc->affinity);
165
166         return 0;
167 }
168 #else
169 static inline int setup_affinity(unsigned int irq, struct irq_desc *d)
170 {
171         return irq_select_affinity(irq);
172 }
173 #endif
174
175 /*
176  * Called when affinity is set via /proc/irq
177  */
178 int irq_select_affinity_usr(unsigned int irq)
179 {
180         struct irq_desc *desc = irq_to_desc(irq);
181         unsigned long flags;
182         int ret;
183
184         raw_spin_lock_irqsave(&desc->lock, flags);
185         ret = setup_affinity(irq, desc);
186         if (!ret)
187                 irq_set_thread_affinity(desc);
188         raw_spin_unlock_irqrestore(&desc->lock, flags);
189
190         return ret;
191 }
192
193 #else
194 static inline int setup_affinity(unsigned int irq, struct irq_desc *desc)
195 {
196         return 0;
197 }
198 #endif
199
200 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
201 {
202         if (suspend) {
203                 if (!desc->action || (desc->action->flags & IRQF_TIMER))
204                         return;
205                 desc->status |= IRQ_SUSPENDED;
206         }
207
208         if (!desc->depth++) {
209                 desc->status |= IRQ_DISABLED;
210                 desc->chip->disable(irq);
211         }
212 }
213
214 /**
215  *      disable_irq_nosync - disable an irq without waiting
216  *      @irq: Interrupt to disable
217  *
218  *      Disable the selected interrupt line.  Disables and Enables are
219  *      nested.
220  *      Unlike disable_irq(), this function does not ensure existing
221  *      instances of the IRQ handler have completed before returning.
222  *
223  *      This function may be called from IRQ context.
224  */
225 void disable_irq_nosync(unsigned int irq)
226 {
227         struct irq_desc *desc = irq_to_desc(irq);
228         unsigned long flags;
229
230         if (!desc)
231                 return;
232
233         chip_bus_lock(irq, desc);
234         raw_spin_lock_irqsave(&desc->lock, flags);
235         __disable_irq(desc, irq, false);
236         raw_spin_unlock_irqrestore(&desc->lock, flags);
237         chip_bus_sync_unlock(irq, desc);
238 }
239 EXPORT_SYMBOL(disable_irq_nosync);
240
241 /**
242  *      disable_irq - disable an irq and wait for completion
243  *      @irq: Interrupt to disable
244  *
245  *      Disable the selected interrupt line.  Enables and Disables are
246  *      nested.
247  *      This function waits for any pending IRQ handlers for this interrupt
248  *      to complete before returning. If you use this function while
249  *      holding a resource the IRQ handler may need you will deadlock.
250  *
251  *      This function may be called - with care - from IRQ context.
252  */
253 void disable_irq(unsigned int irq)
254 {
255         struct irq_desc *desc = irq_to_desc(irq);
256
257         if (!desc)
258                 return;
259
260         disable_irq_nosync(irq);
261         if (desc->action)
262                 synchronize_irq(irq);
263 }
264 EXPORT_SYMBOL(disable_irq);
265
266 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
267 {
268         if (resume)
269                 desc->status &= ~IRQ_SUSPENDED;
270
271         switch (desc->depth) {
272         case 0:
273  err_out:
274                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
275                 break;
276         case 1: {
277                 unsigned int status = desc->status & ~IRQ_DISABLED;
278
279                 if (desc->status & IRQ_SUSPENDED)
280                         goto err_out;
281                 /* Prevent probing on this irq: */
282                 desc->status = status | IRQ_NOPROBE;
283                 check_irq_resend(desc, irq);
284                 /* fall-through */
285         }
286         default:
287                 desc->depth--;
288         }
289 }
290
291 /**
292  *      enable_irq - enable handling of an irq
293  *      @irq: Interrupt to enable
294  *
295  *      Undoes the effect of one call to disable_irq().  If this
296  *      matches the last disable, processing of interrupts on this
297  *      IRQ line is re-enabled.
298  *
299  *      This function may be called from IRQ context only when
300  *      desc->chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
301  */
302 void enable_irq(unsigned int irq)
303 {
304         struct irq_desc *desc = irq_to_desc(irq);
305         unsigned long flags;
306
307         if (!desc)
308                 return;
309
310         chip_bus_lock(irq, desc);
311         raw_spin_lock_irqsave(&desc->lock, flags);
312         __enable_irq(desc, irq, false);
313         raw_spin_unlock_irqrestore(&desc->lock, flags);
314         chip_bus_sync_unlock(irq, desc);
315 }
316 EXPORT_SYMBOL(enable_irq);
317
318 static int set_irq_wake_real(unsigned int irq, unsigned int on)
319 {
320         struct irq_desc *desc = irq_to_desc(irq);
321         int ret = -ENXIO;
322
323         if (desc->chip->set_wake)
324                 ret = desc->chip->set_wake(irq, on);
325
326         return ret;
327 }
328
329 /**
330  *      set_irq_wake - control irq power management wakeup
331  *      @irq:   interrupt to control
332  *      @on:    enable/disable power management wakeup
333  *
334  *      Enable/disable power management wakeup mode, which is
335  *      disabled by default.  Enables and disables must match,
336  *      just as they match for non-wakeup mode support.
337  *
338  *      Wakeup mode lets this IRQ wake the system from sleep
339  *      states like "suspend to RAM".
340  */
341 int set_irq_wake(unsigned int irq, unsigned int on)
342 {
343         struct irq_desc *desc = irq_to_desc(irq);
344         unsigned long flags;
345         int ret = 0;
346
347         /* wakeup-capable irqs can be shared between drivers that
348          * don't need to have the same sleep mode behaviors.
349          */
350         raw_spin_lock_irqsave(&desc->lock, flags);
351         if (on) {
352                 if (desc->wake_depth++ == 0) {
353                         ret = set_irq_wake_real(irq, on);
354                         if (ret)
355                                 desc->wake_depth = 0;
356                         else
357                                 desc->status |= IRQ_WAKEUP;
358                 }
359         } else {
360                 if (desc->wake_depth == 0) {
361                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
362                 } else if (--desc->wake_depth == 0) {
363                         ret = set_irq_wake_real(irq, on);
364                         if (ret)
365                                 desc->wake_depth = 1;
366                         else
367                                 desc->status &= ~IRQ_WAKEUP;
368                 }
369         }
370
371         raw_spin_unlock_irqrestore(&desc->lock, flags);
372         return ret;
373 }
374 EXPORT_SYMBOL(set_irq_wake);
375
376 /*
377  * Internal function that tells the architecture code whether a
378  * particular irq has been exclusively allocated or is available
379  * for driver use.
380  */
381 int can_request_irq(unsigned int irq, unsigned long irqflags)
382 {
383         struct irq_desc *desc = irq_to_desc(irq);
384         struct irqaction *action;
385
386         if (!desc)
387                 return 0;
388
389         if (desc->status & IRQ_NOREQUEST)
390                 return 0;
391
392         action = desc->action;
393         if (action)
394                 if (irqflags & action->flags & IRQF_SHARED)
395                         action = NULL;
396
397         return !action;
398 }
399
400 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
401 {
402         /*
403          * If the architecture still has not overriden
404          * the flow handler then zap the default. This
405          * should catch incorrect flow-type setting.
406          */
407         if (desc->handle_irq == &handle_bad_irq)
408                 desc->handle_irq = NULL;
409 }
410
411 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
412                 unsigned long flags)
413 {
414         int ret;
415         struct irq_chip *chip = desc->chip;
416
417         if (!chip || !chip->set_type) {
418                 /*
419                  * IRQF_TRIGGER_* but the PIC does not support multiple
420                  * flow-types?
421                  */
422                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
423                                 chip ? (chip->name ? : "unknown") : "unknown");
424                 return 0;
425         }
426
427         /* caller masked out all except trigger mode flags */
428         ret = chip->set_type(irq, flags);
429
430         if (ret)
431                 pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
432                                 (int)flags, irq, chip->set_type);
433         else {
434                 if (flags & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
435                         flags |= IRQ_LEVEL;
436                 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
437                 desc->status &= ~(IRQ_LEVEL | IRQ_TYPE_SENSE_MASK);
438                 desc->status |= flags;
439         }
440
441         return ret;
442 }
443
444 /*
445  * Default primary interrupt handler for threaded interrupts. Is
446  * assigned as primary handler when request_threaded_irq is called
447  * with handler == NULL. Useful for oneshot interrupts.
448  */
449 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
450 {
451         return IRQ_WAKE_THREAD;
452 }
453
454 /*
455  * Primary handler for nested threaded interrupts. Should never be
456  * called.
457  */
458 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
459 {
460         WARN(1, "Primary handler called for nested irq %d\n", irq);
461         return IRQ_NONE;
462 }
463
464 static int irq_wait_for_interrupt(struct irqaction *action)
465 {
466         while (!kthread_should_stop()) {
467                 set_current_state(TASK_INTERRUPTIBLE);
468
469                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
470                                        &action->thread_flags)) {
471                         __set_current_state(TASK_RUNNING);
472                         return 0;
473                 }
474                 schedule();
475         }
476         return -1;
477 }
478
479 /*
480  * Oneshot interrupts keep the irq line masked until the threaded
481  * handler finished. unmask if the interrupt has not been disabled and
482  * is marked MASKED.
483  */
484 static void irq_finalize_oneshot(unsigned int irq, struct irq_desc *desc)
485 {
486         chip_bus_lock(irq, desc);
487         raw_spin_lock_irq(&desc->lock);
488         if (!(desc->status & IRQ_DISABLED) && (desc->status & IRQ_MASKED)) {
489                 desc->status &= ~IRQ_MASKED;
490                 desc->chip->unmask(irq);
491         }
492         raw_spin_unlock_irq(&desc->lock);
493         chip_bus_sync_unlock(irq, desc);
494 }
495
496 #ifdef CONFIG_SMP
497 /*
498  * Check whether we need to change the affinity of the interrupt thread.
499  */
500 static void
501 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
502 {
503         cpumask_var_t mask;
504
505         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
506                 return;
507
508         /*
509          * In case we are out of memory we set IRQTF_AFFINITY again and
510          * try again next time
511          */
512         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
513                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
514                 return;
515         }
516
517         raw_spin_lock_irq(&desc->lock);
518         cpumask_copy(mask, desc->affinity);
519         raw_spin_unlock_irq(&desc->lock);
520
521         set_cpus_allowed_ptr(current, mask);
522         free_cpumask_var(mask);
523 }
524 #else
525 static inline void
526 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
527 #endif
528
529 /*
530  * Interrupt handler thread
531  */
532 static int irq_thread(void *data)
533 {
534         struct sched_param param = { .sched_priority = MAX_USER_RT_PRIO/2, };
535         struct irqaction *action = data;
536         struct irq_desc *desc = irq_to_desc(action->irq);
537         int wake, oneshot = desc->status & IRQ_ONESHOT;
538
539         sched_setscheduler(current, SCHED_FIFO, &param);
540         current->irqaction = action;
541
542         while (!irq_wait_for_interrupt(action)) {
543
544                 irq_thread_check_affinity(desc, action);
545
546                 atomic_inc(&desc->threads_active);
547
548                 raw_spin_lock_irq(&desc->lock);
549                 if (unlikely(desc->status & IRQ_DISABLED)) {
550                         /*
551                          * CHECKME: We might need a dedicated
552                          * IRQ_THREAD_PENDING flag here, which
553                          * retriggers the thread in check_irq_resend()
554                          * but AFAICT IRQ_PENDING should be fine as it
555                          * retriggers the interrupt itself --- tglx
556                          */
557                         desc->status |= IRQ_PENDING;
558                         raw_spin_unlock_irq(&desc->lock);
559                 } else {
560                         raw_spin_unlock_irq(&desc->lock);
561
562                         action->thread_fn(action->irq, action->dev_id);
563
564                         if (oneshot)
565                                 irq_finalize_oneshot(action->irq, desc);
566                 }
567
568                 wake = atomic_dec_and_test(&desc->threads_active);
569
570                 if (wake && waitqueue_active(&desc->wait_for_threads))
571                         wake_up(&desc->wait_for_threads);
572         }
573
574         /*
575          * Clear irqaction. Otherwise exit_irq_thread() would make
576          * fuzz about an active irq thread going into nirvana.
577          */
578         current->irqaction = NULL;
579         return 0;
580 }
581
582 /*
583  * Called from do_exit()
584  */
585 void exit_irq_thread(void)
586 {
587         struct task_struct *tsk = current;
588
589         if (!tsk->irqaction)
590                 return;
591
592         printk(KERN_ERR
593                "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
594                tsk->comm ? tsk->comm : "", tsk->pid, tsk->irqaction->irq);
595
596         /*
597          * Set the THREAD DIED flag to prevent further wakeups of the
598          * soon to be gone threaded handler.
599          */
600         set_bit(IRQTF_DIED, &tsk->irqaction->flags);
601 }
602
603 /*
604  * Internal function to register an irqaction - typically used to
605  * allocate special interrupts that are part of the architecture.
606  */
607 static int
608 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
609 {
610         struct irqaction *old, **old_ptr;
611         const char *old_name = NULL;
612         unsigned long flags;
613         int nested, shared = 0;
614         int ret;
615
616         if (!desc)
617                 return -EINVAL;
618
619         if (desc->chip == &no_irq_chip)
620                 return -ENOSYS;
621         /*
622          * Some drivers like serial.c use request_irq() heavily,
623          * so we have to be careful not to interfere with a
624          * running system.
625          */
626         if (new->flags & IRQF_SAMPLE_RANDOM) {
627                 /*
628                  * This function might sleep, we want to call it first,
629                  * outside of the atomic block.
630                  * Yes, this might clear the entropy pool if the wrong
631                  * driver is attempted to be loaded, without actually
632                  * installing a new handler, but is this really a problem,
633                  * only the sysadmin is able to do this.
634                  */
635                 rand_initialize_irq(irq);
636         }
637
638         /* Oneshot interrupts are not allowed with shared */
639         if ((new->flags & IRQF_ONESHOT) && (new->flags & IRQF_SHARED))
640                 return -EINVAL;
641
642         /*
643          * Check whether the interrupt nests into another interrupt
644          * thread.
645          */
646         nested = desc->status & IRQ_NESTED_THREAD;
647         if (nested) {
648                 if (!new->thread_fn)
649                         return -EINVAL;
650                 /*
651                  * Replace the primary handler which was provided from
652                  * the driver for non nested interrupt handling by the
653                  * dummy function which warns when called.
654                  */
655                 new->handler = irq_nested_primary_handler;
656         }
657
658         /*
659          * Create a handler thread when a thread function is supplied
660          * and the interrupt does not nest into another interrupt
661          * thread.
662          */
663         if (new->thread_fn && !nested) {
664                 struct task_struct *t;
665
666                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
667                                    new->name);
668                 if (IS_ERR(t))
669                         return PTR_ERR(t);
670                 /*
671                  * We keep the reference to the task struct even if
672                  * the thread dies to avoid that the interrupt code
673                  * references an already freed task_struct.
674                  */
675                 get_task_struct(t);
676                 new->thread = t;
677         }
678
679         /*
680          * The following block of code has to be executed atomically
681          */
682         raw_spin_lock_irqsave(&desc->lock, flags);
683         old_ptr = &desc->action;
684         old = *old_ptr;
685         if (old) {
686                 /*
687                  * Can't share interrupts unless both agree to and are
688                  * the same type (level, edge, polarity). So both flag
689                  * fields must have IRQF_SHARED set and the bits which
690                  * set the trigger type must match.
691                  */
692                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
693                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
694                         old_name = old->name;
695                         goto mismatch;
696                 }
697
698 #if defined(CONFIG_IRQ_PER_CPU)
699                 /* All handlers must agree on per-cpuness */
700                 if ((old->flags & IRQF_PERCPU) !=
701                     (new->flags & IRQF_PERCPU))
702                         goto mismatch;
703 #endif
704
705                 /* add new interrupt at end of irq queue */
706                 do {
707                         old_ptr = &old->next;
708                         old = *old_ptr;
709                 } while (old);
710                 shared = 1;
711         }
712
713         if (!shared) {
714                 irq_chip_set_defaults(desc->chip);
715
716                 init_waitqueue_head(&desc->wait_for_threads);
717
718                 /* Setup the type (level, edge polarity) if configured: */
719                 if (new->flags & IRQF_TRIGGER_MASK) {
720                         ret = __irq_set_trigger(desc, irq,
721                                         new->flags & IRQF_TRIGGER_MASK);
722
723                         if (ret)
724                                 goto out_thread;
725                 } else
726                         compat_irq_chip_set_default_handler(desc);
727 #if defined(CONFIG_IRQ_PER_CPU)
728                 if (new->flags & IRQF_PERCPU)
729                         desc->status |= IRQ_PER_CPU;
730 #endif
731
732                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING | IRQ_ONESHOT |
733                                   IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
734
735                 if (new->flags & IRQF_ONESHOT)
736                         desc->status |= IRQ_ONESHOT;
737
738                 if (!(desc->status & IRQ_NOAUTOEN)) {
739                         desc->depth = 0;
740                         desc->status &= ~IRQ_DISABLED;
741                         desc->chip->startup(irq);
742                 } else
743                         /* Undo nested disables: */
744                         desc->depth = 1;
745
746                 /* Exclude IRQ from balancing if requested */
747                 if (new->flags & IRQF_NOBALANCING)
748                         desc->status |= IRQ_NO_BALANCING;
749
750                 /* Set default affinity mask once everything is setup */
751                 setup_affinity(irq, desc);
752
753         } else if ((new->flags & IRQF_TRIGGER_MASK)
754                         && (new->flags & IRQF_TRIGGER_MASK)
755                                 != (desc->status & IRQ_TYPE_SENSE_MASK)) {
756                 /* hope the handler works with the actual trigger mode... */
757                 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
758                                 irq, (int)(desc->status & IRQ_TYPE_SENSE_MASK),
759                                 (int)(new->flags & IRQF_TRIGGER_MASK));
760         }
761
762         new->irq = irq;
763         *old_ptr = new;
764
765         /* Reset broken irq detection when installing new handler */
766         desc->irq_count = 0;
767         desc->irqs_unhandled = 0;
768
769         /*
770          * Check whether we disabled the irq via the spurious handler
771          * before. Reenable it and give it another chance.
772          */
773         if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
774                 desc->status &= ~IRQ_SPURIOUS_DISABLED;
775                 __enable_irq(desc, irq, false);
776         }
777
778         raw_spin_unlock_irqrestore(&desc->lock, flags);
779
780         /*
781          * Strictly no need to wake it up, but hung_task complains
782          * when no hard interrupt wakes the thread up.
783          */
784         if (new->thread)
785                 wake_up_process(new->thread);
786
787         register_irq_proc(irq, desc);
788         new->dir = NULL;
789         register_handler_proc(irq, new);
790
791         return 0;
792
793 mismatch:
794 #ifdef CONFIG_DEBUG_SHIRQ
795         if (!(new->flags & IRQF_PROBE_SHARED)) {
796                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
797                 if (old_name)
798                         printk(KERN_ERR "current handler: %s\n", old_name);
799                 dump_stack();
800         }
801 #endif
802         ret = -EBUSY;
803
804 out_thread:
805         raw_spin_unlock_irqrestore(&desc->lock, flags);
806         if (new->thread) {
807                 struct task_struct *t = new->thread;
808
809                 new->thread = NULL;
810                 if (likely(!test_bit(IRQTF_DIED, &new->thread_flags)))
811                         kthread_stop(t);
812                 put_task_struct(t);
813         }
814         return ret;
815 }
816
817 /**
818  *      setup_irq - setup an interrupt
819  *      @irq: Interrupt line to setup
820  *      @act: irqaction for the interrupt
821  *
822  * Used to statically setup interrupts in the early boot process.
823  */
824 int setup_irq(unsigned int irq, struct irqaction *act)
825 {
826         struct irq_desc *desc = irq_to_desc(irq);
827
828         return __setup_irq(irq, desc, act);
829 }
830 EXPORT_SYMBOL_GPL(setup_irq);
831
832  /*
833  * Internal function to unregister an irqaction - used to free
834  * regular and special interrupts that are part of the architecture.
835  */
836 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
837 {
838         struct irq_desc *desc = irq_to_desc(irq);
839         struct irqaction *action, **action_ptr;
840         unsigned long flags;
841
842         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
843
844         if (!desc)
845                 return NULL;
846
847         raw_spin_lock_irqsave(&desc->lock, flags);
848
849         /*
850          * There can be multiple actions per IRQ descriptor, find the right
851          * one based on the dev_id:
852          */
853         action_ptr = &desc->action;
854         for (;;) {
855                 action = *action_ptr;
856
857                 if (!action) {
858                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
859                         raw_spin_unlock_irqrestore(&desc->lock, flags);
860
861                         return NULL;
862                 }
863
864                 if (action->dev_id == dev_id)
865                         break;
866                 action_ptr = &action->next;
867         }
868
869         /* Found it - now remove it from the list of entries: */
870         *action_ptr = action->next;
871
872         /* Currently used only by UML, might disappear one day: */
873 #ifdef CONFIG_IRQ_RELEASE_METHOD
874         if (desc->chip->release)
875                 desc->chip->release(irq, dev_id);
876 #endif
877
878         /* If this was the last handler, shut down the IRQ line: */
879         if (!desc->action) {
880                 desc->status |= IRQ_DISABLED;
881                 if (desc->chip->shutdown)
882                         desc->chip->shutdown(irq);
883                 else
884                         desc->chip->disable(irq);
885         }
886
887         raw_spin_unlock_irqrestore(&desc->lock, flags);
888
889         unregister_handler_proc(irq, action);
890
891         /* Make sure it's not being used on another CPU: */
892         synchronize_irq(irq);
893
894 #ifdef CONFIG_DEBUG_SHIRQ
895         /*
896          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
897          * event to happen even now it's being freed, so let's make sure that
898          * is so by doing an extra call to the handler ....
899          *
900          * ( We do this after actually deregistering it, to make sure that a
901          *   'real' IRQ doesn't run in * parallel with our fake. )
902          */
903         if (action->flags & IRQF_SHARED) {
904                 local_irq_save(flags);
905                 action->handler(irq, dev_id);
906                 local_irq_restore(flags);
907         }
908 #endif
909
910         if (action->thread) {
911                 if (!test_bit(IRQTF_DIED, &action->thread_flags))
912                         kthread_stop(action->thread);
913                 put_task_struct(action->thread);
914         }
915
916         return action;
917 }
918
919 /**
920  *      remove_irq - free an interrupt
921  *      @irq: Interrupt line to free
922  *      @act: irqaction for the interrupt
923  *
924  * Used to remove interrupts statically setup by the early boot process.
925  */
926 void remove_irq(unsigned int irq, struct irqaction *act)
927 {
928         __free_irq(irq, act->dev_id);
929 }
930 EXPORT_SYMBOL_GPL(remove_irq);
931
932 /**
933  *      free_irq - free an interrupt allocated with request_irq
934  *      @irq: Interrupt line to free
935  *      @dev_id: Device identity to free
936  *
937  *      Remove an interrupt handler. The handler is removed and if the
938  *      interrupt line is no longer in use by any driver it is disabled.
939  *      On a shared IRQ the caller must ensure the interrupt is disabled
940  *      on the card it drives before calling this function. The function
941  *      does not return until any executing interrupts for this IRQ
942  *      have completed.
943  *
944  *      This function must not be called from interrupt context.
945  */
946 void free_irq(unsigned int irq, void *dev_id)
947 {
948         struct irq_desc *desc = irq_to_desc(irq);
949
950         if (!desc)
951                 return;
952
953         chip_bus_lock(irq, desc);
954         kfree(__free_irq(irq, dev_id));
955         chip_bus_sync_unlock(irq, desc);
956 }
957 EXPORT_SYMBOL(free_irq);
958
959 /**
960  *      request_threaded_irq - allocate an interrupt line
961  *      @irq: Interrupt line to allocate
962  *      @handler: Function to be called when the IRQ occurs.
963  *                Primary handler for threaded interrupts
964  *                If NULL and thread_fn != NULL the default
965  *                primary handler is installed
966  *      @thread_fn: Function called from the irq handler thread
967  *                  If NULL, no irq thread is created
968  *      @irqflags: Interrupt type flags
969  *      @devname: An ascii name for the claiming device
970  *      @dev_id: A cookie passed back to the handler function
971  *
972  *      This call allocates interrupt resources and enables the
973  *      interrupt line and IRQ handling. From the point this
974  *      call is made your handler function may be invoked. Since
975  *      your handler function must clear any interrupt the board
976  *      raises, you must take care both to initialise your hardware
977  *      and to set up the interrupt handler in the right order.
978  *
979  *      If you want to set up a threaded irq handler for your device
980  *      then you need to supply @handler and @thread_fn. @handler ist
981  *      still called in hard interrupt context and has to check
982  *      whether the interrupt originates from the device. If yes it
983  *      needs to disable the interrupt on the device and return
984  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
985  *      @thread_fn. This split handler design is necessary to support
986  *      shared interrupts.
987  *
988  *      Dev_id must be globally unique. Normally the address of the
989  *      device data structure is used as the cookie. Since the handler
990  *      receives this value it makes sense to use it.
991  *
992  *      If your interrupt is shared you must pass a non NULL dev_id
993  *      as this is required when freeing the interrupt.
994  *
995  *      Flags:
996  *
997  *      IRQF_SHARED             Interrupt is shared
998  *      IRQF_DISABLED   Disable local interrupts while processing
999  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
1000  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1001  *
1002  */
1003 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1004                          irq_handler_t thread_fn, unsigned long irqflags,
1005                          const char *devname, void *dev_id)
1006 {
1007         struct irqaction *action;
1008         struct irq_desc *desc;
1009         int retval;
1010
1011         /*
1012          * handle_IRQ_event() always ignores IRQF_DISABLED except for
1013          * the _first_ irqaction (sigh).  That can cause oopsing, but
1014          * the behavior is classified as "will not fix" so we need to
1015          * start nudging drivers away from using that idiom.
1016          */
1017         if ((irqflags & (IRQF_SHARED|IRQF_DISABLED)) ==
1018                                         (IRQF_SHARED|IRQF_DISABLED)) {
1019                 pr_warning(
1020                   "IRQ %d/%s: IRQF_DISABLED is not guaranteed on shared IRQs\n",
1021                         irq, devname);
1022         }
1023
1024 #ifdef CONFIG_LOCKDEP
1025         /*
1026          * Lockdep wants atomic interrupt handlers:
1027          */
1028         irqflags |= IRQF_DISABLED;
1029 #endif
1030         /*
1031          * Sanity-check: shared interrupts must pass in a real dev-ID,
1032          * otherwise we'll have trouble later trying to figure out
1033          * which interrupt is which (messes up the interrupt freeing
1034          * logic etc).
1035          */
1036         if ((irqflags & IRQF_SHARED) && !dev_id)
1037                 return -EINVAL;
1038
1039         desc = irq_to_desc(irq);
1040         if (!desc)
1041                 return -EINVAL;
1042
1043         if (desc->status & IRQ_NOREQUEST)
1044                 return -EINVAL;
1045
1046         if (!handler) {
1047                 if (!thread_fn)
1048                         return -EINVAL;
1049                 handler = irq_default_primary_handler;
1050         }
1051
1052         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1053         if (!action)
1054                 return -ENOMEM;
1055
1056         action->handler = handler;
1057         action->thread_fn = thread_fn;
1058         action->flags = irqflags;
1059         action->name = devname;
1060         action->dev_id = dev_id;
1061
1062         chip_bus_lock(irq, desc);
1063         retval = __setup_irq(irq, desc, action);
1064         chip_bus_sync_unlock(irq, desc);
1065
1066         if (retval)
1067                 kfree(action);
1068
1069 #ifdef CONFIG_DEBUG_SHIRQ
1070         if (!retval && (irqflags & IRQF_SHARED)) {
1071                 /*
1072                  * It's a shared IRQ -- the driver ought to be prepared for it
1073                  * to happen immediately, so let's make sure....
1074                  * We disable the irq to make sure that a 'real' IRQ doesn't
1075                  * run in parallel with our fake.
1076                  */
1077                 unsigned long flags;
1078
1079                 disable_irq(irq);
1080                 local_irq_save(flags);
1081
1082                 handler(irq, dev_id);
1083
1084                 local_irq_restore(flags);
1085                 enable_irq(irq);
1086         }
1087 #endif
1088         return retval;
1089 }
1090 EXPORT_SYMBOL(request_threaded_irq);