3284118f356b90c8ae1ec7320d71ce143d704220
[linux-2.6.git] / arch / arm / kernel / irq.c
1 /*
2  *  linux/arch/arm/kernel/irq.c
3  *
4  *  Copyright (C) 1992 Linus Torvalds
5  *  Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
6  *
7  *  Support for Dynamic Tick Timer Copyright (C) 2004-2005 Nokia Corporation.
8  *  Dynamic Tick Timer written by Tony Lindgren <tony@atomide.com> and
9  *  Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>.
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License version 2 as
13  * published by the Free Software Foundation.
14  *
15  *  This file contains the code used by various IRQ handling routines:
16  *  asking for different IRQ's should be done through these routines
17  *  instead of just grabbing them. Thus setups with different IRQ numbers
18  *  shouldn't result in any weird surprises, and installing new handlers
19  *  should be easier.
20  *
21  *  IRQ's are in fact implemented a bit like signal handlers for the kernel.
22  *  Naturally it's not a 1:1 relation, but there are similarities.
23  */
24 #include <linux/config.h>
25 #include <linux/kernel_stat.h>
26 #include <linux/module.h>
27 #include <linux/signal.h>
28 #include <linux/ioport.h>
29 #include <linux/interrupt.h>
30 #include <linux/ptrace.h>
31 #include <linux/slab.h>
32 #include <linux/random.h>
33 #include <linux/smp.h>
34 #include <linux/init.h>
35 #include <linux/seq_file.h>
36 #include <linux/errno.h>
37 #include <linux/list.h>
38 #include <linux/kallsyms.h>
39 #include <linux/proc_fs.h>
40
41 #include <asm/irq.h>
42 #include <asm/system.h>
43 #include <asm/mach/irq.h>
44 #include <asm/mach/time.h>
45
46 /*
47  * Maximum IRQ count.  Currently, this is arbitary.  However, it should
48  * not be set too low to prevent false triggering.  Conversely, if it
49  * is set too high, then you could miss a stuck IRQ.
50  *
51  * Maybe we ought to set a timer and re-enable the IRQ at a later time?
52  */
53 #define MAX_IRQ_CNT     100000
54
55 static int noirqdebug;
56 static volatile unsigned long irq_err_count;
57 static DEFINE_SPINLOCK(irq_controller_lock);
58 static LIST_HEAD(irq_pending);
59
60 struct irqdesc irq_desc[NR_IRQS];
61 void (*init_arch_irq)(void) __initdata = NULL;
62
63 /*
64  * No architecture-specific irq_finish function defined in arm/arch/irqs.h.
65  */
66 #ifndef irq_finish
67 #define irq_finish(irq) do { } while (0)
68 #endif
69
70 /*
71  * Dummy mask/unmask handler
72  */
73 void dummy_mask_unmask_irq(unsigned int irq)
74 {
75 }
76
77 irqreturn_t no_action(int irq, void *dev_id, struct pt_regs *regs)
78 {
79         return IRQ_NONE;
80 }
81
82 void do_bad_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
83 {
84         irq_err_count += 1;
85         printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
86 }
87
88 static struct irqchip bad_chip = {
89         .ack    = dummy_mask_unmask_irq,
90         .mask   = dummy_mask_unmask_irq,
91         .unmask = dummy_mask_unmask_irq,
92 };
93
94 static struct irqdesc bad_irq_desc = {
95         .chip           = &bad_chip,
96         .handle         = do_bad_IRQ,
97         .pend           = LIST_HEAD_INIT(bad_irq_desc.pend),
98         .disable_depth  = 1,
99 };
100
101 #ifdef CONFIG_SMP
102 void synchronize_irq(unsigned int irq)
103 {
104         struct irqdesc *desc = irq_desc + irq;
105
106         while (desc->running)
107                 barrier();
108 }
109 EXPORT_SYMBOL(synchronize_irq);
110
111 #define smp_set_running(desc)   do { desc->running = 1; } while (0)
112 #define smp_clear_running(desc) do { desc->running = 0; } while (0)
113 #else
114 #define smp_set_running(desc)   do { } while (0)
115 #define smp_clear_running(desc) do { } while (0)
116 #endif
117
118 /**
119  *      disable_irq_nosync - disable an irq without waiting
120  *      @irq: Interrupt to disable
121  *
122  *      Disable the selected interrupt line.  Enables and disables
123  *      are nested.  We do this lazily.
124  *
125  *      This function may be called from IRQ context.
126  */
127 void disable_irq_nosync(unsigned int irq)
128 {
129         struct irqdesc *desc = irq_desc + irq;
130         unsigned long flags;
131
132         spin_lock_irqsave(&irq_controller_lock, flags);
133         desc->disable_depth++;
134         list_del_init(&desc->pend);
135         spin_unlock_irqrestore(&irq_controller_lock, flags);
136 }
137 EXPORT_SYMBOL(disable_irq_nosync);
138
139 /**
140  *      disable_irq - disable an irq and wait for completion
141  *      @irq: Interrupt to disable
142  *
143  *      Disable the selected interrupt line.  Enables and disables
144  *      are nested.  This functions waits for any pending IRQ
145  *      handlers for this interrupt to complete before returning.
146  *      If you use this function while holding a resource the IRQ
147  *      handler may need you will deadlock.
148  *
149  *      This function may be called - with care - from IRQ context.
150  */
151 void disable_irq(unsigned int irq)
152 {
153         struct irqdesc *desc = irq_desc + irq;
154
155         disable_irq_nosync(irq);
156         if (desc->action)
157                 synchronize_irq(irq);
158 }
159 EXPORT_SYMBOL(disable_irq);
160
161 /**
162  *      enable_irq - enable interrupt handling on an irq
163  *      @irq: Interrupt to enable
164  *
165  *      Re-enables the processing of interrupts on this IRQ line.
166  *      Note that this may call the interrupt handler, so you may
167  *      get unexpected results if you hold IRQs disabled.
168  *
169  *      This function may be called from IRQ context.
170  */
171 void enable_irq(unsigned int irq)
172 {
173         struct irqdesc *desc = irq_desc + irq;
174         unsigned long flags;
175
176         spin_lock_irqsave(&irq_controller_lock, flags);
177         if (unlikely(!desc->disable_depth)) {
178                 printk("enable_irq(%u) unbalanced from %p\n", irq,
179                         __builtin_return_address(0));
180         } else if (!--desc->disable_depth) {
181                 desc->probing = 0;
182                 desc->chip->unmask(irq);
183
184                 /*
185                  * If the interrupt is waiting to be processed,
186                  * try to re-run it.  We can't directly run it
187                  * from here since the caller might be in an
188                  * interrupt-protected region.
189                  */
190                 if (desc->pending && list_empty(&desc->pend)) {
191                         desc->pending = 0;
192                         if (!desc->chip->retrigger ||
193                             desc->chip->retrigger(irq))
194                                 list_add(&desc->pend, &irq_pending);
195                 }
196         }
197         spin_unlock_irqrestore(&irq_controller_lock, flags);
198 }
199 EXPORT_SYMBOL(enable_irq);
200
201 /*
202  * Enable wake on selected irq
203  */
204 void enable_irq_wake(unsigned int irq)
205 {
206         struct irqdesc *desc = irq_desc + irq;
207         unsigned long flags;
208
209         spin_lock_irqsave(&irq_controller_lock, flags);
210         if (desc->chip->set_wake)
211                 desc->chip->set_wake(irq, 1);
212         spin_unlock_irqrestore(&irq_controller_lock, flags);
213 }
214 EXPORT_SYMBOL(enable_irq_wake);
215
216 void disable_irq_wake(unsigned int irq)
217 {
218         struct irqdesc *desc = irq_desc + irq;
219         unsigned long flags;
220
221         spin_lock_irqsave(&irq_controller_lock, flags);
222         if (desc->chip->set_wake)
223                 desc->chip->set_wake(irq, 0);
224         spin_unlock_irqrestore(&irq_controller_lock, flags);
225 }
226 EXPORT_SYMBOL(disable_irq_wake);
227
228 int show_interrupts(struct seq_file *p, void *v)
229 {
230         int i = *(loff_t *) v, cpu;
231         struct irqaction * action;
232         unsigned long flags;
233
234         if (i == 0) {
235                 char cpuname[12];
236
237                 seq_printf(p, "    ");
238                 for_each_present_cpu(cpu) {
239                         sprintf(cpuname, "CPU%d", cpu);
240                         seq_printf(p, " %10s", cpuname);
241                 }
242                 seq_putc(p, '\n');
243         }
244
245         if (i < NR_IRQS) {
246                 spin_lock_irqsave(&irq_controller_lock, flags);
247                 action = irq_desc[i].action;
248                 if (!action)
249                         goto unlock;
250
251                 seq_printf(p, "%3d: ", i);
252                 for_each_present_cpu(cpu)
253                         seq_printf(p, "%10u ", kstat_cpu(cpu).irqs[i]);
254                 seq_printf(p, "  %s", action->name);
255                 for (action = action->next; action; action = action->next)
256                         seq_printf(p, ", %s", action->name);
257
258                 seq_putc(p, '\n');
259 unlock:
260                 spin_unlock_irqrestore(&irq_controller_lock, flags);
261         } else if (i == NR_IRQS) {
262 #ifdef CONFIG_ARCH_ACORN
263                 show_fiq_list(p, v);
264 #endif
265 #ifdef CONFIG_SMP
266                 show_ipi_list(p);
267 #endif
268                 seq_printf(p, "Err: %10lu\n", irq_err_count);
269         }
270         return 0;
271 }
272
273 /*
274  * IRQ lock detection.
275  *
276  * Hopefully, this should get us out of a few locked situations.
277  * However, it may take a while for this to happen, since we need
278  * a large number if IRQs to appear in the same jiffie with the
279  * same instruction pointer (or within 2 instructions).
280  */
281 static int check_irq_lock(struct irqdesc *desc, int irq, struct pt_regs *regs)
282 {
283         unsigned long instr_ptr = instruction_pointer(regs);
284
285         if (desc->lck_jif == jiffies &&
286             desc->lck_pc >= instr_ptr && desc->lck_pc < instr_ptr + 8) {
287                 desc->lck_cnt += 1;
288
289                 if (desc->lck_cnt > MAX_IRQ_CNT) {
290                         printk(KERN_ERR "IRQ LOCK: IRQ%d is locking the system, disabled\n", irq);
291                         return 1;
292                 }
293         } else {
294                 desc->lck_cnt = 0;
295                 desc->lck_pc  = instruction_pointer(regs);
296                 desc->lck_jif = jiffies;
297         }
298         return 0;
299 }
300
301 static void
302 report_bad_irq(unsigned int irq, struct pt_regs *regs, struct irqdesc *desc, int ret)
303 {
304         static int count = 100;
305         struct irqaction *action;
306
307         if (!count || noirqdebug)
308                 return;
309
310         count--;
311
312         if (ret != IRQ_HANDLED && ret != IRQ_NONE) {
313                 printk("irq%u: bogus retval mask %x\n", irq, ret);
314         } else {
315                 printk("irq%u: nobody cared\n", irq);
316         }
317         show_regs(regs);
318         dump_stack();
319         printk(KERN_ERR "handlers:");
320         action = desc->action;
321         do {
322                 printk("\n" KERN_ERR "[<%p>]", action->handler);
323                 print_symbol(" (%s)", (unsigned long)action->handler);
324                 action = action->next;
325         } while (action);
326         printk("\n");
327 }
328
329 static int
330 __do_irq(unsigned int irq, struct irqaction *action, struct pt_regs *regs)
331 {
332         unsigned int status;
333         int ret, retval = 0;
334
335         spin_unlock(&irq_controller_lock);
336
337 #ifdef CONFIG_NO_IDLE_HZ
338         if (!(action->flags & SA_TIMER) && system_timer->dyn_tick != NULL) {
339                 write_seqlock(&xtime_lock);
340                 if (system_timer->dyn_tick->state & DYN_TICK_ENABLED)
341                         system_timer->dyn_tick->handler(irq, 0, regs);
342                 write_sequnlock(&xtime_lock);
343         }
344 #endif
345
346         if (!(action->flags & SA_INTERRUPT))
347                 local_irq_enable();
348
349         status = 0;
350         do {
351                 ret = action->handler(irq, action->dev_id, regs);
352                 if (ret == IRQ_HANDLED)
353                         status |= action->flags;
354                 retval |= ret;
355                 action = action->next;
356         } while (action);
357
358         if (status & SA_SAMPLE_RANDOM)
359                 add_interrupt_randomness(irq);
360
361         spin_lock_irq(&irq_controller_lock);
362
363         return retval;
364 }
365
366 /*
367  * This is for software-decoded IRQs.  The caller is expected to
368  * handle the ack, clear, mask and unmask issues.
369  */
370 void
371 do_simple_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
372 {
373         struct irqaction *action;
374         const unsigned int cpu = smp_processor_id();
375
376         desc->triggered = 1;
377
378         kstat_cpu(cpu).irqs[irq]++;
379
380         smp_set_running(desc);
381
382         action = desc->action;
383         if (action) {
384                 int ret = __do_irq(irq, action, regs);
385                 if (ret != IRQ_HANDLED)
386                         report_bad_irq(irq, regs, desc, ret);
387         }
388
389         smp_clear_running(desc);
390 }
391
392 /*
393  * Most edge-triggered IRQ implementations seem to take a broken
394  * approach to this.  Hence the complexity.
395  */
396 void
397 do_edge_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
398 {
399         const unsigned int cpu = smp_processor_id();
400
401         desc->triggered = 1;
402
403         /*
404          * If we're currently running this IRQ, or its disabled,
405          * we shouldn't process the IRQ.  Instead, turn on the
406          * hardware masks.
407          */
408         if (unlikely(desc->running || desc->disable_depth))
409                 goto running;
410
411         /*
412          * Acknowledge and clear the IRQ, but don't mask it.
413          */
414         desc->chip->ack(irq);
415
416         /*
417          * Mark the IRQ currently in progress.
418          */
419         desc->running = 1;
420
421         kstat_cpu(cpu).irqs[irq]++;
422
423         do {
424                 struct irqaction *action;
425
426                 action = desc->action;
427                 if (!action)
428                         break;
429
430                 if (desc->pending && !desc->disable_depth) {
431                         desc->pending = 0;
432                         desc->chip->unmask(irq);
433                 }
434
435                 __do_irq(irq, action, regs);
436         } while (desc->pending && !desc->disable_depth);
437
438         desc->running = 0;
439
440         /*
441          * If we were disabled or freed, shut down the handler.
442          */
443         if (likely(desc->action && !check_irq_lock(desc, irq, regs)))
444                 return;
445
446  running:
447         /*
448          * We got another IRQ while this one was masked or
449          * currently running.  Delay it.
450          */
451         desc->pending = 1;
452         desc->chip->mask(irq);
453         desc->chip->ack(irq);
454 }
455
456 /*
457  * Level-based IRQ handler.  Nice and simple.
458  */
459 void
460 do_level_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
461 {
462         struct irqaction *action;
463         const unsigned int cpu = smp_processor_id();
464
465         desc->triggered = 1;
466
467         /*
468          * Acknowledge, clear _AND_ disable the interrupt.
469          */
470         desc->chip->ack(irq);
471
472         if (likely(!desc->disable_depth)) {
473                 kstat_cpu(cpu).irqs[irq]++;
474
475                 smp_set_running(desc);
476
477                 /*
478                  * Return with this interrupt masked if no action
479                  */
480                 action = desc->action;
481                 if (action) {
482                         int ret = __do_irq(irq, desc->action, regs);
483
484                         if (ret != IRQ_HANDLED)
485                                 report_bad_irq(irq, regs, desc, ret);
486
487                         if (likely(!desc->disable_depth &&
488                                    !check_irq_lock(desc, irq, regs)))
489                                 desc->chip->unmask(irq);
490                 }
491
492                 smp_clear_running(desc);
493         }
494 }
495
496 static void do_pending_irqs(struct pt_regs *regs)
497 {
498         struct list_head head, *l, *n;
499
500         do {
501                 struct irqdesc *desc;
502
503                 /*
504                  * First, take the pending interrupts off the list.
505                  * The act of calling the handlers may add some IRQs
506                  * back onto the list.
507                  */
508                 head = irq_pending;
509                 INIT_LIST_HEAD(&irq_pending);
510                 head.next->prev = &head;
511                 head.prev->next = &head;
512
513                 /*
514                  * Now run each entry.  We must delete it from our
515                  * list before calling the handler.
516                  */
517                 list_for_each_safe(l, n, &head) {
518                         desc = list_entry(l, struct irqdesc, pend);
519                         list_del_init(&desc->pend);
520                         desc_handle_irq(desc - irq_desc, desc, regs);
521                 }
522
523                 /*
524                  * The list must be empty.
525                  */
526                 BUG_ON(!list_empty(&head));
527         } while (!list_empty(&irq_pending));
528 }
529
530 /*
531  * do_IRQ handles all hardware IRQ's.  Decoded IRQs should not
532  * come via this function.  Instead, they should provide their
533  * own 'handler'
534  */
535 asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
536 {
537         struct irqdesc *desc = irq_desc + irq;
538
539         /*
540          * Some hardware gives randomly wrong interrupts.  Rather
541          * than crashing, do something sensible.
542          */
543         if (irq >= NR_IRQS)
544                 desc = &bad_irq_desc;
545
546         irq_enter();
547         spin_lock(&irq_controller_lock);
548         desc_handle_irq(irq, desc, regs);
549
550         /*
551          * Now re-run any pending interrupts.
552          */
553         if (!list_empty(&irq_pending))
554                 do_pending_irqs(regs);
555
556         irq_finish(irq);
557
558         spin_unlock(&irq_controller_lock);
559         irq_exit();
560 }
561
562 void __set_irq_handler(unsigned int irq, irq_handler_t handle, int is_chained)
563 {
564         struct irqdesc *desc;
565         unsigned long flags;
566
567         if (irq >= NR_IRQS) {
568                 printk(KERN_ERR "Trying to install handler for IRQ%d\n", irq);
569                 return;
570         }
571
572         if (handle == NULL)
573                 handle = do_bad_IRQ;
574
575         desc = irq_desc + irq;
576
577         if (is_chained && desc->chip == &bad_chip)
578                 printk(KERN_WARNING "Trying to install chained handler for IRQ%d\n", irq);
579
580         spin_lock_irqsave(&irq_controller_lock, flags);
581         if (handle == do_bad_IRQ) {
582                 desc->chip->mask(irq);
583                 desc->chip->ack(irq);
584                 desc->disable_depth = 1;
585         }
586         desc->handle = handle;
587         if (handle != do_bad_IRQ && is_chained) {
588                 desc->valid = 0;
589                 desc->probe_ok = 0;
590                 desc->disable_depth = 0;
591                 desc->chip->unmask(irq);
592         }
593         spin_unlock_irqrestore(&irq_controller_lock, flags);
594 }
595
596 void set_irq_chip(unsigned int irq, struct irqchip *chip)
597 {
598         struct irqdesc *desc;
599         unsigned long flags;
600
601         if (irq >= NR_IRQS) {
602                 printk(KERN_ERR "Trying to install chip for IRQ%d\n", irq);
603                 return;
604         }
605
606         if (chip == NULL)
607                 chip = &bad_chip;
608
609         desc = irq_desc + irq;
610         spin_lock_irqsave(&irq_controller_lock, flags);
611         desc->chip = chip;
612         spin_unlock_irqrestore(&irq_controller_lock, flags);
613 }
614
615 int set_irq_type(unsigned int irq, unsigned int type)
616 {
617         struct irqdesc *desc;
618         unsigned long flags;
619         int ret = -ENXIO;
620
621         if (irq >= NR_IRQS) {
622                 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
623                 return -ENODEV;
624         }
625
626         desc = irq_desc + irq;
627         if (desc->chip->set_type) {
628                 spin_lock_irqsave(&irq_controller_lock, flags);
629                 ret = desc->chip->set_type(irq, type);
630                 spin_unlock_irqrestore(&irq_controller_lock, flags);
631         }
632
633         return ret;
634 }
635 EXPORT_SYMBOL(set_irq_type);
636
637 void set_irq_flags(unsigned int irq, unsigned int iflags)
638 {
639         struct irqdesc *desc;
640         unsigned long flags;
641
642         if (irq >= NR_IRQS) {
643                 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
644                 return;
645         }
646
647         desc = irq_desc + irq;
648         spin_lock_irqsave(&irq_controller_lock, flags);
649         desc->valid = (iflags & IRQF_VALID) != 0;
650         desc->probe_ok = (iflags & IRQF_PROBE) != 0;
651         desc->noautoenable = (iflags & IRQF_NOAUTOEN) != 0;
652         spin_unlock_irqrestore(&irq_controller_lock, flags);
653 }
654
655 int setup_irq(unsigned int irq, struct irqaction *new)
656 {
657         int shared = 0;
658         struct irqaction *old, **p;
659         unsigned long flags;
660         struct irqdesc *desc;
661
662         /*
663          * Some drivers like serial.c use request_irq() heavily,
664          * so we have to be careful not to interfere with a
665          * running system.
666          */
667         if (new->flags & SA_SAMPLE_RANDOM) {
668                 /*
669                  * This function might sleep, we want to call it first,
670                  * outside of the atomic block.
671                  * Yes, this might clear the entropy pool if the wrong
672                  * driver is attempted to be loaded, without actually
673                  * installing a new handler, but is this really a problem,
674                  * only the sysadmin is able to do this.
675                  */
676                 rand_initialize_irq(irq);
677         }
678
679         /*
680          * The following block of code has to be executed atomically
681          */
682         desc = irq_desc + irq;
683         spin_lock_irqsave(&irq_controller_lock, flags);
684         p = &desc->action;
685         if ((old = *p) != NULL) {
686                 /* Can't share interrupts unless both agree to */
687                 if (!(old->flags & new->flags & SA_SHIRQ)) {
688                         spin_unlock_irqrestore(&irq_controller_lock, flags);
689                         return -EBUSY;
690                 }
691
692                 /* add new interrupt at end of irq queue */
693                 do {
694                         p = &old->next;
695                         old = *p;
696                 } while (old);
697                 shared = 1;
698         }
699
700         *p = new;
701
702         if (!shared) {
703                 desc->probing = 0;
704                 desc->running = 0;
705                 desc->pending = 0;
706                 desc->disable_depth = 1;
707                 if (!desc->noautoenable) {
708                         desc->disable_depth = 0;
709                         desc->chip->unmask(irq);
710                 }
711         }
712
713         spin_unlock_irqrestore(&irq_controller_lock, flags);
714         return 0;
715 }
716
717 /**
718  *      request_irq - allocate an interrupt line
719  *      @irq: Interrupt line to allocate
720  *      @handler: Function to be called when the IRQ occurs
721  *      @irqflags: Interrupt type flags
722  *      @devname: An ascii name for the claiming device
723  *      @dev_id: A cookie passed back to the handler function
724  *
725  *      This call allocates interrupt resources and enables the
726  *      interrupt line and IRQ handling. From the point this
727  *      call is made your handler function may be invoked. Since
728  *      your handler function must clear any interrupt the board
729  *      raises, you must take care both to initialise your hardware
730  *      and to set up the interrupt handler in the right order.
731  *
732  *      Dev_id must be globally unique. Normally the address of the
733  *      device data structure is used as the cookie. Since the handler
734  *      receives this value it makes sense to use it.
735  *
736  *      If your interrupt is shared you must pass a non NULL dev_id
737  *      as this is required when freeing the interrupt.
738  *
739  *      Flags:
740  *
741  *      SA_SHIRQ                Interrupt is shared
742  *
743  *      SA_INTERRUPT            Disable local interrupts while processing
744  *
745  *      SA_SAMPLE_RANDOM        The interrupt can be used for entropy
746  *
747  */
748 int request_irq(unsigned int irq, irqreturn_t (*handler)(int, void *, struct pt_regs *),
749                  unsigned long irq_flags, const char * devname, void *dev_id)
750 {
751         unsigned long retval;
752         struct irqaction *action;
753
754         if (irq >= NR_IRQS || !irq_desc[irq].valid || !handler ||
755             (irq_flags & SA_SHIRQ && !dev_id))
756                 return -EINVAL;
757
758         action = (struct irqaction *)kmalloc(sizeof(struct irqaction), GFP_KERNEL);
759         if (!action)
760                 return -ENOMEM;
761
762         action->handler = handler;
763         action->flags = irq_flags;
764         cpus_clear(action->mask);
765         action->name = devname;
766         action->next = NULL;
767         action->dev_id = dev_id;
768
769         retval = setup_irq(irq, action);
770
771         if (retval)
772                 kfree(action);
773         return retval;
774 }
775
776 EXPORT_SYMBOL(request_irq);
777
778 /**
779  *      free_irq - free an interrupt
780  *      @irq: Interrupt line to free
781  *      @dev_id: Device identity to free
782  *
783  *      Remove an interrupt handler. The handler is removed and if the
784  *      interrupt line is no longer in use by any driver it is disabled.
785  *      On a shared IRQ the caller must ensure the interrupt is disabled
786  *      on the card it drives before calling this function.
787  *
788  *      This function must not be called from interrupt context.
789  */
790 void free_irq(unsigned int irq, void *dev_id)
791 {
792         struct irqaction * action, **p;
793         unsigned long flags;
794
795         if (irq >= NR_IRQS || !irq_desc[irq].valid) {
796                 printk(KERN_ERR "Trying to free IRQ%d\n",irq);
797                 dump_stack();
798                 return;
799         }
800
801         spin_lock_irqsave(&irq_controller_lock, flags);
802         for (p = &irq_desc[irq].action; (action = *p) != NULL; p = &action->next) {
803                 if (action->dev_id != dev_id)
804                         continue;
805
806                 /* Found it - now free it */
807                 *p = action->next;
808                 break;
809         }
810         spin_unlock_irqrestore(&irq_controller_lock, flags);
811
812         if (!action) {
813                 printk(KERN_ERR "Trying to free free IRQ%d\n",irq);
814                 dump_stack();
815         } else {
816                 synchronize_irq(irq);
817                 kfree(action);
818         }
819 }
820
821 EXPORT_SYMBOL(free_irq);
822
823 static DECLARE_MUTEX(probe_sem);
824
825 /* Start the interrupt probing.  Unlike other architectures,
826  * we don't return a mask of interrupts from probe_irq_on,
827  * but return the number of interrupts enabled for the probe.
828  * The interrupts which have been enabled for probing is
829  * instead recorded in the irq_desc structure.
830  */
831 unsigned long probe_irq_on(void)
832 {
833         unsigned int i, irqs = 0;
834         unsigned long delay;
835
836         down(&probe_sem);
837
838         /*
839          * first snaffle up any unassigned but
840          * probe-able interrupts
841          */
842         spin_lock_irq(&irq_controller_lock);
843         for (i = 0; i < NR_IRQS; i++) {
844                 if (!irq_desc[i].probe_ok || irq_desc[i].action)
845                         continue;
846
847                 irq_desc[i].probing = 1;
848                 irq_desc[i].triggered = 0;
849                 if (irq_desc[i].chip->set_type)
850                         irq_desc[i].chip->set_type(i, IRQT_PROBE);
851                 irq_desc[i].chip->unmask(i);
852                 irqs += 1;
853         }
854         spin_unlock_irq(&irq_controller_lock);
855
856         /*
857          * wait for spurious interrupts to mask themselves out again
858          */
859         for (delay = jiffies + HZ/10; time_before(jiffies, delay); )
860                 /* min 100ms delay */;
861
862         /*
863          * now filter out any obviously spurious interrupts
864          */
865         spin_lock_irq(&irq_controller_lock);
866         for (i = 0; i < NR_IRQS; i++) {
867                 if (irq_desc[i].probing && irq_desc[i].triggered) {
868                         irq_desc[i].probing = 0;
869                         irqs -= 1;
870                 }
871         }
872         spin_unlock_irq(&irq_controller_lock);
873
874         return irqs;
875 }
876
877 EXPORT_SYMBOL(probe_irq_on);
878
879 unsigned int probe_irq_mask(unsigned long irqs)
880 {
881         unsigned int mask = 0, i;
882
883         spin_lock_irq(&irq_controller_lock);
884         for (i = 0; i < 16 && i < NR_IRQS; i++)
885                 if (irq_desc[i].probing && irq_desc[i].triggered)
886                         mask |= 1 << i;
887         spin_unlock_irq(&irq_controller_lock);
888
889         up(&probe_sem);
890
891         return mask;
892 }
893 EXPORT_SYMBOL(probe_irq_mask);
894
895 /*
896  * Possible return values:
897  *  >= 0 - interrupt number
898  *    -1 - no interrupt/many interrupts
899  */
900 int probe_irq_off(unsigned long irqs)
901 {
902         unsigned int i;
903         int irq_found = NO_IRQ;
904
905         /*
906          * look at the interrupts, and find exactly one
907          * that we were probing has been triggered
908          */
909         spin_lock_irq(&irq_controller_lock);
910         for (i = 0; i < NR_IRQS; i++) {
911                 if (irq_desc[i].probing &&
912                     irq_desc[i].triggered) {
913                         if (irq_found != NO_IRQ) {
914                                 irq_found = NO_IRQ;
915                                 goto out;
916                         }
917                         irq_found = i;
918                 }
919         }
920
921         if (irq_found == -1)
922                 irq_found = NO_IRQ;
923 out:
924         spin_unlock_irq(&irq_controller_lock);
925
926         up(&probe_sem);
927
928         return irq_found;
929 }
930
931 EXPORT_SYMBOL(probe_irq_off);
932
933 #ifdef CONFIG_SMP
934 static void route_irq(struct irqdesc *desc, unsigned int irq, unsigned int cpu)
935 {
936         pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->cpu, cpu);
937
938         spin_lock_irq(&irq_controller_lock);
939         desc->cpu = cpu;
940         desc->chip->set_cpu(desc, irq, cpu);
941         spin_unlock_irq(&irq_controller_lock);
942 }
943
944 #ifdef CONFIG_PROC_FS
945 static int
946 irq_affinity_read_proc(char *page, char **start, off_t off, int count,
947                        int *eof, void *data)
948 {
949         struct irqdesc *desc = irq_desc + ((int)data);
950         int len = cpumask_scnprintf(page, count, desc->affinity);
951
952         if (count - len < 2)
953                 return -EINVAL;
954         page[len++] = '\n';
955         page[len] = '\0';
956
957         return len;
958 }
959
960 static int
961 irq_affinity_write_proc(struct file *file, const char __user *buffer,
962                         unsigned long count, void *data)
963 {
964         unsigned int irq = (unsigned int)data;
965         struct irqdesc *desc = irq_desc + irq;
966         cpumask_t affinity, tmp;
967         int ret = -EIO;
968
969         if (!desc->chip->set_cpu)
970                 goto out;
971
972         ret = cpumask_parse(buffer, count, affinity);
973         if (ret)
974                 goto out;
975
976         cpus_and(tmp, affinity, cpu_online_map);
977         if (cpus_empty(tmp)) {
978                 ret = -EINVAL;
979                 goto out;
980         }
981
982         desc->affinity = affinity;
983         route_irq(desc, irq, first_cpu(tmp));
984         ret = count;
985
986  out:
987         return ret;
988 }
989 #endif
990 #endif
991
992 void __init init_irq_proc(void)
993 {
994 #if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
995         struct proc_dir_entry *dir;
996         int irq;
997
998         dir = proc_mkdir("irq", 0);
999         if (!dir)
1000                 return;
1001
1002         for (irq = 0; irq < NR_IRQS; irq++) {
1003                 struct proc_dir_entry *entry;
1004                 struct irqdesc *desc;
1005                 char name[16];
1006
1007                 desc = irq_desc + irq;
1008                 memset(name, 0, sizeof(name));
1009                 snprintf(name, sizeof(name) - 1, "%u", irq);
1010
1011                 desc->procdir = proc_mkdir(name, dir);
1012                 if (!desc->procdir)
1013                         continue;
1014
1015                 entry = create_proc_entry("smp_affinity", 0600, desc->procdir);
1016                 if (entry) {
1017                         entry->nlink = 1;
1018                         entry->data = (void *)irq;
1019                         entry->read_proc = irq_affinity_read_proc;
1020                         entry->write_proc = irq_affinity_write_proc;
1021                 }
1022         }
1023 #endif
1024 }
1025
1026 void __init init_IRQ(void)
1027 {
1028         struct irqdesc *desc;
1029         extern void init_dma(void);
1030         int irq;
1031
1032 #ifdef CONFIG_SMP
1033         bad_irq_desc.affinity = CPU_MASK_ALL;
1034         bad_irq_desc.cpu = smp_processor_id();
1035 #endif
1036
1037         for (irq = 0, desc = irq_desc; irq < NR_IRQS; irq++, desc++) {
1038                 *desc = bad_irq_desc;
1039                 INIT_LIST_HEAD(&desc->pend);
1040         }
1041
1042         init_arch_irq();
1043         init_dma();
1044 }
1045
1046 static int __init noirqdebug_setup(char *str)
1047 {
1048         noirqdebug = 1;
1049         return 1;
1050 }
1051
1052 __setup("noirqdebug", noirqdebug_setup);