Linux-2.6.12-rc2
[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  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  *
11  *  This file contains the code used by various IRQ handling routines:
12  *  asking for different IRQ's should be done through these routines
13  *  instead of just grabbing them. Thus setups with different IRQ numbers
14  *  shouldn't result in any weird surprises, and installing new handlers
15  *  should be easier.
16  *
17  *  IRQ's are in fact implemented a bit like signal handlers for the kernel.
18  *  Naturally it's not a 1:1 relation, but there are similarities.
19  */
20 #include <linux/config.h>
21 #include <linux/kernel_stat.h>
22 #include <linux/module.h>
23 #include <linux/signal.h>
24 #include <linux/ioport.h>
25 #include <linux/interrupt.h>
26 #include <linux/ptrace.h>
27 #include <linux/slab.h>
28 #include <linux/random.h>
29 #include <linux/smp.h>
30 #include <linux/init.h>
31 #include <linux/seq_file.h>
32 #include <linux/errno.h>
33 #include <linux/list.h>
34 #include <linux/kallsyms.h>
35 #include <linux/proc_fs.h>
36
37 #include <asm/irq.h>
38 #include <asm/system.h>
39 #include <asm/mach/irq.h>
40
41 /*
42  * Maximum IRQ count.  Currently, this is arbitary.  However, it should
43  * not be set too low to prevent false triggering.  Conversely, if it
44  * is set too high, then you could miss a stuck IRQ.
45  *
46  * Maybe we ought to set a timer and re-enable the IRQ at a later time?
47  */
48 #define MAX_IRQ_CNT     100000
49
50 static int noirqdebug;
51 static volatile unsigned long irq_err_count;
52 static DEFINE_SPINLOCK(irq_controller_lock);
53 static LIST_HEAD(irq_pending);
54
55 struct irqdesc irq_desc[NR_IRQS];
56 void (*init_arch_irq)(void) __initdata = NULL;
57
58 /*
59  * No architecture-specific irq_finish function defined in arm/arch/irqs.h.
60  */
61 #ifndef irq_finish
62 #define irq_finish(irq) do { } while (0)
63 #endif
64
65 /*
66  * Dummy mask/unmask handler
67  */
68 void dummy_mask_unmask_irq(unsigned int irq)
69 {
70 }
71
72 irqreturn_t no_action(int irq, void *dev_id, struct pt_regs *regs)
73 {
74         return IRQ_NONE;
75 }
76
77 void do_bad_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
78 {
79         irq_err_count += 1;
80         printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
81 }
82
83 static struct irqchip bad_chip = {
84         .ack    = dummy_mask_unmask_irq,
85         .mask   = dummy_mask_unmask_irq,
86         .unmask = dummy_mask_unmask_irq,
87 };
88
89 static struct irqdesc bad_irq_desc = {
90         .chip           = &bad_chip,
91         .handle         = do_bad_IRQ,
92         .pend           = LIST_HEAD_INIT(bad_irq_desc.pend),
93         .disable_depth  = 1,
94 };
95
96 #ifdef CONFIG_SMP
97 void synchronize_irq(unsigned int irq)
98 {
99         struct irqdesc *desc = irq_desc + irq;
100
101         while (desc->running)
102                 barrier();
103 }
104 EXPORT_SYMBOL(synchronize_irq);
105
106 #define smp_set_running(desc)   do { desc->running = 1; } while (0)
107 #define smp_clear_running(desc) do { desc->running = 0; } while (0)
108 #else
109 #define smp_set_running(desc)   do { } while (0)
110 #define smp_clear_running(desc) do { } while (0)
111 #endif
112
113 /**
114  *      disable_irq_nosync - disable an irq without waiting
115  *      @irq: Interrupt to disable
116  *
117  *      Disable the selected interrupt line.  Enables and disables
118  *      are nested.  We do this lazily.
119  *
120  *      This function may be called from IRQ context.
121  */
122 void disable_irq_nosync(unsigned int irq)
123 {
124         struct irqdesc *desc = irq_desc + irq;
125         unsigned long flags;
126
127         spin_lock_irqsave(&irq_controller_lock, flags);
128         desc->disable_depth++;
129         list_del_init(&desc->pend);
130         spin_unlock_irqrestore(&irq_controller_lock, flags);
131 }
132 EXPORT_SYMBOL(disable_irq_nosync);
133
134 /**
135  *      disable_irq - disable an irq and wait for completion
136  *      @irq: Interrupt to disable
137  *
138  *      Disable the selected interrupt line.  Enables and disables
139  *      are nested.  This functions waits for any pending IRQ
140  *      handlers for this interrupt to complete before returning.
141  *      If you use this function while holding a resource the IRQ
142  *      handler may need you will deadlock.
143  *
144  *      This function may be called - with care - from IRQ context.
145  */
146 void disable_irq(unsigned int irq)
147 {
148         struct irqdesc *desc = irq_desc + irq;
149
150         disable_irq_nosync(irq);
151         if (desc->action)
152                 synchronize_irq(irq);
153 }
154 EXPORT_SYMBOL(disable_irq);
155
156 /**
157  *      enable_irq - enable interrupt handling on an irq
158  *      @irq: Interrupt to enable
159  *
160  *      Re-enables the processing of interrupts on this IRQ line.
161  *      Note that this may call the interrupt handler, so you may
162  *      get unexpected results if you hold IRQs disabled.
163  *
164  *      This function may be called from IRQ context.
165  */
166 void enable_irq(unsigned int irq)
167 {
168         struct irqdesc *desc = irq_desc + irq;
169         unsigned long flags;
170
171         spin_lock_irqsave(&irq_controller_lock, flags);
172         if (unlikely(!desc->disable_depth)) {
173                 printk("enable_irq(%u) unbalanced from %p\n", irq,
174                         __builtin_return_address(0));
175         } else if (!--desc->disable_depth) {
176                 desc->probing = 0;
177                 desc->chip->unmask(irq);
178
179                 /*
180                  * If the interrupt is waiting to be processed,
181                  * try to re-run it.  We can't directly run it
182                  * from here since the caller might be in an
183                  * interrupt-protected region.
184                  */
185                 if (desc->pending && list_empty(&desc->pend)) {
186                         desc->pending = 0;
187                         if (!desc->chip->retrigger ||
188                             desc->chip->retrigger(irq))
189                                 list_add(&desc->pend, &irq_pending);
190                 }
191         }
192         spin_unlock_irqrestore(&irq_controller_lock, flags);
193 }
194 EXPORT_SYMBOL(enable_irq);
195
196 /*
197  * Enable wake on selected irq
198  */
199 void enable_irq_wake(unsigned int irq)
200 {
201         struct irqdesc *desc = irq_desc + irq;
202         unsigned long flags;
203
204         spin_lock_irqsave(&irq_controller_lock, flags);
205         if (desc->chip->wake)
206                 desc->chip->wake(irq, 1);
207         spin_unlock_irqrestore(&irq_controller_lock, flags);
208 }
209 EXPORT_SYMBOL(enable_irq_wake);
210
211 void disable_irq_wake(unsigned int irq)
212 {
213         struct irqdesc *desc = irq_desc + irq;
214         unsigned long flags;
215
216         spin_lock_irqsave(&irq_controller_lock, flags);
217         if (desc->chip->wake)
218                 desc->chip->wake(irq, 0);
219         spin_unlock_irqrestore(&irq_controller_lock, flags);
220 }
221 EXPORT_SYMBOL(disable_irq_wake);
222
223 int show_interrupts(struct seq_file *p, void *v)
224 {
225         int i = *(loff_t *) v, cpu;
226         struct irqaction * action;
227         unsigned long flags;
228
229         if (i == 0) {
230                 char cpuname[12];
231
232                 seq_printf(p, "    ");
233                 for_each_present_cpu(cpu) {
234                         sprintf(cpuname, "CPU%d", cpu);
235                         seq_printf(p, " %10s", cpuname);
236                 }
237                 seq_putc(p, '\n');
238         }
239
240         if (i < NR_IRQS) {
241                 spin_lock_irqsave(&irq_controller_lock, flags);
242                 action = irq_desc[i].action;
243                 if (!action)
244                         goto unlock;
245
246                 seq_printf(p, "%3d: ", i);
247                 for_each_present_cpu(cpu)
248                         seq_printf(p, "%10u ", kstat_cpu(cpu).irqs[i]);
249                 seq_printf(p, "  %s", action->name);
250                 for (action = action->next; action; action = action->next)
251                         seq_printf(p, ", %s", action->name);
252
253                 seq_putc(p, '\n');
254 unlock:
255                 spin_unlock_irqrestore(&irq_controller_lock, flags);
256         } else if (i == NR_IRQS) {
257 #ifdef CONFIG_ARCH_ACORN
258                 show_fiq_list(p, v);
259 #endif
260 #ifdef CONFIG_SMP
261                 show_ipi_list(p);
262 #endif
263                 seq_printf(p, "Err: %10lu\n", irq_err_count);
264         }
265         return 0;
266 }
267
268 /*
269  * IRQ lock detection.
270  *
271  * Hopefully, this should get us out of a few locked situations.
272  * However, it may take a while for this to happen, since we need
273  * a large number if IRQs to appear in the same jiffie with the
274  * same instruction pointer (or within 2 instructions).
275  */
276 static int check_irq_lock(struct irqdesc *desc, int irq, struct pt_regs *regs)
277 {
278         unsigned long instr_ptr = instruction_pointer(regs);
279
280         if (desc->lck_jif == jiffies &&
281             desc->lck_pc >= instr_ptr && desc->lck_pc < instr_ptr + 8) {
282                 desc->lck_cnt += 1;
283
284                 if (desc->lck_cnt > MAX_IRQ_CNT) {
285                         printk(KERN_ERR "IRQ LOCK: IRQ%d is locking the system, disabled\n", irq);
286                         return 1;
287                 }
288         } else {
289                 desc->lck_cnt = 0;
290                 desc->lck_pc  = instruction_pointer(regs);
291                 desc->lck_jif = jiffies;
292         }
293         return 0;
294 }
295
296 static void
297 report_bad_irq(unsigned int irq, struct pt_regs *regs, struct irqdesc *desc, int ret)
298 {
299         static int count = 100;
300         struct irqaction *action;
301
302         if (!count || noirqdebug)
303                 return;
304
305         count--;
306
307         if (ret != IRQ_HANDLED && ret != IRQ_NONE) {
308                 printk("irq%u: bogus retval mask %x\n", irq, ret);
309         } else {
310                 printk("irq%u: nobody cared\n", irq);
311         }
312         show_regs(regs);
313         dump_stack();
314         printk(KERN_ERR "handlers:");
315         action = desc->action;
316         do {
317                 printk("\n" KERN_ERR "[<%p>]", action->handler);
318                 print_symbol(" (%s)", (unsigned long)action->handler);
319                 action = action->next;
320         } while (action);
321         printk("\n");
322 }
323
324 static int
325 __do_irq(unsigned int irq, struct irqaction *action, struct pt_regs *regs)
326 {
327         unsigned int status;
328         int ret, retval = 0;
329
330         spin_unlock(&irq_controller_lock);
331
332         if (!(action->flags & SA_INTERRUPT))
333                 local_irq_enable();
334
335         status = 0;
336         do {
337                 ret = action->handler(irq, action->dev_id, regs);
338                 if (ret == IRQ_HANDLED)
339                         status |= action->flags;
340                 retval |= ret;
341                 action = action->next;
342         } while (action);
343
344         if (status & SA_SAMPLE_RANDOM)
345                 add_interrupt_randomness(irq);
346
347         spin_lock_irq(&irq_controller_lock);
348
349         return retval;
350 }
351
352 /*
353  * This is for software-decoded IRQs.  The caller is expected to
354  * handle the ack, clear, mask and unmask issues.
355  */
356 void
357 do_simple_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
358 {
359         struct irqaction *action;
360         const unsigned int cpu = smp_processor_id();
361
362         desc->triggered = 1;
363
364         kstat_cpu(cpu).irqs[irq]++;
365
366         smp_set_running(desc);
367
368         action = desc->action;
369         if (action) {
370                 int ret = __do_irq(irq, action, regs);
371                 if (ret != IRQ_HANDLED)
372                         report_bad_irq(irq, regs, desc, ret);
373         }
374
375         smp_clear_running(desc);
376 }
377
378 /*
379  * Most edge-triggered IRQ implementations seem to take a broken
380  * approach to this.  Hence the complexity.
381  */
382 void
383 do_edge_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
384 {
385         const unsigned int cpu = smp_processor_id();
386
387         desc->triggered = 1;
388
389         /*
390          * If we're currently running this IRQ, or its disabled,
391          * we shouldn't process the IRQ.  Instead, turn on the
392          * hardware masks.
393          */
394         if (unlikely(desc->running || desc->disable_depth))
395                 goto running;
396
397         /*
398          * Acknowledge and clear the IRQ, but don't mask it.
399          */
400         desc->chip->ack(irq);
401
402         /*
403          * Mark the IRQ currently in progress.
404          */
405         desc->running = 1;
406
407         kstat_cpu(cpu).irqs[irq]++;
408
409         do {
410                 struct irqaction *action;
411
412                 action = desc->action;
413                 if (!action)
414                         break;
415
416                 if (desc->pending && !desc->disable_depth) {
417                         desc->pending = 0;
418                         desc->chip->unmask(irq);
419                 }
420
421                 __do_irq(irq, action, regs);
422         } while (desc->pending && !desc->disable_depth);
423
424         desc->running = 0;
425
426         /*
427          * If we were disabled or freed, shut down the handler.
428          */
429         if (likely(desc->action && !check_irq_lock(desc, irq, regs)))
430                 return;
431
432  running:
433         /*
434          * We got another IRQ while this one was masked or
435          * currently running.  Delay it.
436          */
437         desc->pending = 1;
438         desc->chip->mask(irq);
439         desc->chip->ack(irq);
440 }
441
442 /*
443  * Level-based IRQ handler.  Nice and simple.
444  */
445 void
446 do_level_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
447 {
448         struct irqaction *action;
449         const unsigned int cpu = smp_processor_id();
450
451         desc->triggered = 1;
452
453         /*
454          * Acknowledge, clear _AND_ disable the interrupt.
455          */
456         desc->chip->ack(irq);
457
458         if (likely(!desc->disable_depth)) {
459                 kstat_cpu(cpu).irqs[irq]++;
460
461                 smp_set_running(desc);
462
463                 /*
464                  * Return with this interrupt masked if no action
465                  */
466                 action = desc->action;
467                 if (action) {
468                         int ret = __do_irq(irq, desc->action, regs);
469
470                         if (ret != IRQ_HANDLED)
471                                 report_bad_irq(irq, regs, desc, ret);
472
473                         if (likely(!desc->disable_depth &&
474                                    !check_irq_lock(desc, irq, regs)))
475                                 desc->chip->unmask(irq);
476                 }
477
478                 smp_clear_running(desc);
479         }
480 }
481
482 static void do_pending_irqs(struct pt_regs *regs)
483 {
484         struct list_head head, *l, *n;
485
486         do {
487                 struct irqdesc *desc;
488
489                 /*
490                  * First, take the pending interrupts off the list.
491                  * The act of calling the handlers may add some IRQs
492                  * back onto the list.
493                  */
494                 head = irq_pending;
495                 INIT_LIST_HEAD(&irq_pending);
496                 head.next->prev = &head;
497                 head.prev->next = &head;
498
499                 /*
500                  * Now run each entry.  We must delete it from our
501                  * list before calling the handler.
502                  */
503                 list_for_each_safe(l, n, &head) {
504                         desc = list_entry(l, struct irqdesc, pend);
505                         list_del_init(&desc->pend);
506                         desc->handle(desc - irq_desc, desc, regs);
507                 }
508
509                 /*
510                  * The list must be empty.
511                  */
512                 BUG_ON(!list_empty(&head));
513         } while (!list_empty(&irq_pending));
514 }
515
516 /*
517  * do_IRQ handles all hardware IRQ's.  Decoded IRQs should not
518  * come via this function.  Instead, they should provide their
519  * own 'handler'
520  */
521 asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
522 {
523         struct irqdesc *desc = irq_desc + irq;
524
525         /*
526          * Some hardware gives randomly wrong interrupts.  Rather
527          * than crashing, do something sensible.
528          */
529         if (irq >= NR_IRQS)
530                 desc = &bad_irq_desc;
531
532         irq_enter();
533         spin_lock(&irq_controller_lock);
534         desc->handle(irq, desc, regs);
535
536         /*
537          * Now re-run any pending interrupts.
538          */
539         if (!list_empty(&irq_pending))
540                 do_pending_irqs(regs);
541
542         irq_finish(irq);
543
544         spin_unlock(&irq_controller_lock);
545         irq_exit();
546 }
547
548 void __set_irq_handler(unsigned int irq, irq_handler_t handle, int is_chained)
549 {
550         struct irqdesc *desc;
551         unsigned long flags;
552
553         if (irq >= NR_IRQS) {
554                 printk(KERN_ERR "Trying to install handler for IRQ%d\n", irq);
555                 return;
556         }
557
558         if (handle == NULL)
559                 handle = do_bad_IRQ;
560
561         desc = irq_desc + irq;
562
563         if (is_chained && desc->chip == &bad_chip)
564                 printk(KERN_WARNING "Trying to install chained handler for IRQ%d\n", irq);
565
566         spin_lock_irqsave(&irq_controller_lock, flags);
567         if (handle == do_bad_IRQ) {
568                 desc->chip->mask(irq);
569                 desc->chip->ack(irq);
570                 desc->disable_depth = 1;
571         }
572         desc->handle = handle;
573         if (handle != do_bad_IRQ && is_chained) {
574                 desc->valid = 0;
575                 desc->probe_ok = 0;
576                 desc->disable_depth = 0;
577                 desc->chip->unmask(irq);
578         }
579         spin_unlock_irqrestore(&irq_controller_lock, flags);
580 }
581
582 void set_irq_chip(unsigned int irq, struct irqchip *chip)
583 {
584         struct irqdesc *desc;
585         unsigned long flags;
586
587         if (irq >= NR_IRQS) {
588                 printk(KERN_ERR "Trying to install chip for IRQ%d\n", irq);
589                 return;
590         }
591
592         if (chip == NULL)
593                 chip = &bad_chip;
594
595         desc = irq_desc + irq;
596         spin_lock_irqsave(&irq_controller_lock, flags);
597         desc->chip = chip;
598         spin_unlock_irqrestore(&irq_controller_lock, flags);
599 }
600
601 int set_irq_type(unsigned int irq, unsigned int type)
602 {
603         struct irqdesc *desc;
604         unsigned long flags;
605         int ret = -ENXIO;
606
607         if (irq >= NR_IRQS) {
608                 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
609                 return -ENODEV;
610         }
611
612         desc = irq_desc + irq;
613         if (desc->chip->type) {
614                 spin_lock_irqsave(&irq_controller_lock, flags);
615                 ret = desc->chip->type(irq, type);
616                 spin_unlock_irqrestore(&irq_controller_lock, flags);
617         }
618
619         return ret;
620 }
621 EXPORT_SYMBOL(set_irq_type);
622
623 void set_irq_flags(unsigned int irq, unsigned int iflags)
624 {
625         struct irqdesc *desc;
626         unsigned long flags;
627
628         if (irq >= NR_IRQS) {
629                 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
630                 return;
631         }
632
633         desc = irq_desc + irq;
634         spin_lock_irqsave(&irq_controller_lock, flags);
635         desc->valid = (iflags & IRQF_VALID) != 0;
636         desc->probe_ok = (iflags & IRQF_PROBE) != 0;
637         desc->noautoenable = (iflags & IRQF_NOAUTOEN) != 0;
638         spin_unlock_irqrestore(&irq_controller_lock, flags);
639 }
640
641 int setup_irq(unsigned int irq, struct irqaction *new)
642 {
643         int shared = 0;
644         struct irqaction *old, **p;
645         unsigned long flags;
646         struct irqdesc *desc;
647
648         /*
649          * Some drivers like serial.c use request_irq() heavily,
650          * so we have to be careful not to interfere with a
651          * running system.
652          */
653         if (new->flags & SA_SAMPLE_RANDOM) {
654                 /*
655                  * This function might sleep, we want to call it first,
656                  * outside of the atomic block.
657                  * Yes, this might clear the entropy pool if the wrong
658                  * driver is attempted to be loaded, without actually
659                  * installing a new handler, but is this really a problem,
660                  * only the sysadmin is able to do this.
661                  */
662                 rand_initialize_irq(irq);
663         }
664
665         /*
666          * The following block of code has to be executed atomically
667          */
668         desc = irq_desc + irq;
669         spin_lock_irqsave(&irq_controller_lock, flags);
670         p = &desc->action;
671         if ((old = *p) != NULL) {
672                 /* Can't share interrupts unless both agree to */
673                 if (!(old->flags & new->flags & SA_SHIRQ)) {
674                         spin_unlock_irqrestore(&irq_controller_lock, flags);
675                         return -EBUSY;
676                 }
677
678                 /* add new interrupt at end of irq queue */
679                 do {
680                         p = &old->next;
681                         old = *p;
682                 } while (old);
683                 shared = 1;
684         }
685
686         *p = new;
687
688         if (!shared) {
689                 desc->probing = 0;
690                 desc->running = 0;
691                 desc->pending = 0;
692                 desc->disable_depth = 1;
693                 if (!desc->noautoenable) {
694                         desc->disable_depth = 0;
695                         desc->chip->unmask(irq);
696                 }
697         }
698
699         spin_unlock_irqrestore(&irq_controller_lock, flags);
700         return 0;
701 }
702
703 /**
704  *      request_irq - allocate an interrupt line
705  *      @irq: Interrupt line to allocate
706  *      @handler: Function to be called when the IRQ occurs
707  *      @irqflags: Interrupt type flags
708  *      @devname: An ascii name for the claiming device
709  *      @dev_id: A cookie passed back to the handler function
710  *
711  *      This call allocates interrupt resources and enables the
712  *      interrupt line and IRQ handling. From the point this
713  *      call is made your handler function may be invoked. Since
714  *      your handler function must clear any interrupt the board
715  *      raises, you must take care both to initialise your hardware
716  *      and to set up the interrupt handler in the right order.
717  *
718  *      Dev_id must be globally unique. Normally the address of the
719  *      device data structure is used as the cookie. Since the handler
720  *      receives this value it makes sense to use it.
721  *
722  *      If your interrupt is shared you must pass a non NULL dev_id
723  *      as this is required when freeing the interrupt.
724  *
725  *      Flags:
726  *
727  *      SA_SHIRQ                Interrupt is shared
728  *
729  *      SA_INTERRUPT            Disable local interrupts while processing
730  *
731  *      SA_SAMPLE_RANDOM        The interrupt can be used for entropy
732  *
733  */
734 int request_irq(unsigned int irq, irqreturn_t (*handler)(int, void *, struct pt_regs *),
735                  unsigned long irq_flags, const char * devname, void *dev_id)
736 {
737         unsigned long retval;
738         struct irqaction *action;
739
740         if (irq >= NR_IRQS || !irq_desc[irq].valid || !handler ||
741             (irq_flags & SA_SHIRQ && !dev_id))
742                 return -EINVAL;
743
744         action = (struct irqaction *)kmalloc(sizeof(struct irqaction), GFP_KERNEL);
745         if (!action)
746                 return -ENOMEM;
747
748         action->handler = handler;
749         action->flags = irq_flags;
750         cpus_clear(action->mask);
751         action->name = devname;
752         action->next = NULL;
753         action->dev_id = dev_id;
754
755         retval = setup_irq(irq, action);
756
757         if (retval)
758                 kfree(action);
759         return retval;
760 }
761
762 EXPORT_SYMBOL(request_irq);
763
764 /**
765  *      free_irq - free an interrupt
766  *      @irq: Interrupt line to free
767  *      @dev_id: Device identity to free
768  *
769  *      Remove an interrupt handler. The handler is removed and if the
770  *      interrupt line is no longer in use by any driver it is disabled.
771  *      On a shared IRQ the caller must ensure the interrupt is disabled
772  *      on the card it drives before calling this function.
773  *
774  *      This function must not be called from interrupt context.
775  */
776 void free_irq(unsigned int irq, void *dev_id)
777 {
778         struct irqaction * action, **p;
779         unsigned long flags;
780
781         if (irq >= NR_IRQS || !irq_desc[irq].valid) {
782                 printk(KERN_ERR "Trying to free IRQ%d\n",irq);
783                 dump_stack();
784                 return;
785         }
786
787         spin_lock_irqsave(&irq_controller_lock, flags);
788         for (p = &irq_desc[irq].action; (action = *p) != NULL; p = &action->next) {
789                 if (action->dev_id != dev_id)
790                         continue;
791
792                 /* Found it - now free it */
793                 *p = action->next;
794                 break;
795         }
796         spin_unlock_irqrestore(&irq_controller_lock, flags);
797
798         if (!action) {
799                 printk(KERN_ERR "Trying to free free IRQ%d\n",irq);
800                 dump_stack();
801         } else {
802                 synchronize_irq(irq);
803                 kfree(action);
804         }
805 }
806
807 EXPORT_SYMBOL(free_irq);
808
809 static DECLARE_MUTEX(probe_sem);
810
811 /* Start the interrupt probing.  Unlike other architectures,
812  * we don't return a mask of interrupts from probe_irq_on,
813  * but return the number of interrupts enabled for the probe.
814  * The interrupts which have been enabled for probing is
815  * instead recorded in the irq_desc structure.
816  */
817 unsigned long probe_irq_on(void)
818 {
819         unsigned int i, irqs = 0;
820         unsigned long delay;
821
822         down(&probe_sem);
823
824         /*
825          * first snaffle up any unassigned but
826          * probe-able interrupts
827          */
828         spin_lock_irq(&irq_controller_lock);
829         for (i = 0; i < NR_IRQS; i++) {
830                 if (!irq_desc[i].probe_ok || irq_desc[i].action)
831                         continue;
832
833                 irq_desc[i].probing = 1;
834                 irq_desc[i].triggered = 0;
835                 if (irq_desc[i].chip->type)
836                         irq_desc[i].chip->type(i, IRQT_PROBE);
837                 irq_desc[i].chip->unmask(i);
838                 irqs += 1;
839         }
840         spin_unlock_irq(&irq_controller_lock);
841
842         /*
843          * wait for spurious interrupts to mask themselves out again
844          */
845         for (delay = jiffies + HZ/10; time_before(jiffies, delay); )
846                 /* min 100ms delay */;
847
848         /*
849          * now filter out any obviously spurious interrupts
850          */
851         spin_lock_irq(&irq_controller_lock);
852         for (i = 0; i < NR_IRQS; i++) {
853                 if (irq_desc[i].probing && irq_desc[i].triggered) {
854                         irq_desc[i].probing = 0;
855                         irqs -= 1;
856                 }
857         }
858         spin_unlock_irq(&irq_controller_lock);
859
860         return irqs;
861 }
862
863 EXPORT_SYMBOL(probe_irq_on);
864
865 unsigned int probe_irq_mask(unsigned long irqs)
866 {
867         unsigned int mask = 0, i;
868
869         spin_lock_irq(&irq_controller_lock);
870         for (i = 0; i < 16 && i < NR_IRQS; i++)
871                 if (irq_desc[i].probing && irq_desc[i].triggered)
872                         mask |= 1 << i;
873         spin_unlock_irq(&irq_controller_lock);
874
875         up(&probe_sem);
876
877         return mask;
878 }
879 EXPORT_SYMBOL(probe_irq_mask);
880
881 /*
882  * Possible return values:
883  *  >= 0 - interrupt number
884  *    -1 - no interrupt/many interrupts
885  */
886 int probe_irq_off(unsigned long irqs)
887 {
888         unsigned int i;
889         int irq_found = NO_IRQ;
890
891         /*
892          * look at the interrupts, and find exactly one
893          * that we were probing has been triggered
894          */
895         spin_lock_irq(&irq_controller_lock);
896         for (i = 0; i < NR_IRQS; i++) {
897                 if (irq_desc[i].probing &&
898                     irq_desc[i].triggered) {
899                         if (irq_found != NO_IRQ) {
900                                 irq_found = NO_IRQ;
901                                 goto out;
902                         }
903                         irq_found = i;
904                 }
905         }
906
907         if (irq_found == -1)
908                 irq_found = NO_IRQ;
909 out:
910         spin_unlock_irq(&irq_controller_lock);
911
912         up(&probe_sem);
913
914         return irq_found;
915 }
916
917 EXPORT_SYMBOL(probe_irq_off);
918
919 #ifdef CONFIG_SMP
920 static void route_irq(struct irqdesc *desc, unsigned int irq, unsigned int cpu)
921 {
922         pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->cpu, cpu);
923
924         spin_lock_irq(&irq_controller_lock);
925         desc->cpu = cpu;
926         desc->chip->set_cpu(desc, irq, cpu);
927         spin_unlock_irq(&irq_controller_lock);
928 }
929
930 #ifdef CONFIG_PROC_FS
931 static int
932 irq_affinity_read_proc(char *page, char **start, off_t off, int count,
933                        int *eof, void *data)
934 {
935         struct irqdesc *desc = irq_desc + ((int)data);
936         int len = cpumask_scnprintf(page, count, desc->affinity);
937
938         if (count - len < 2)
939                 return -EINVAL;
940         page[len++] = '\n';
941         page[len] = '\0';
942
943         return len;
944 }
945
946 static int
947 irq_affinity_write_proc(struct file *file, const char __user *buffer,
948                         unsigned long count, void *data)
949 {
950         unsigned int irq = (unsigned int)data;
951         struct irqdesc *desc = irq_desc + irq;
952         cpumask_t affinity, tmp;
953         int ret = -EIO;
954
955         if (!desc->chip->set_cpu)
956                 goto out;
957
958         ret = cpumask_parse(buffer, count, affinity);
959         if (ret)
960                 goto out;
961
962         cpus_and(tmp, affinity, cpu_online_map);
963         if (cpus_empty(tmp)) {
964                 ret = -EINVAL;
965                 goto out;
966         }
967
968         desc->affinity = affinity;
969         route_irq(desc, irq, first_cpu(tmp));
970         ret = count;
971
972  out:
973         return ret;
974 }
975 #endif
976 #endif
977
978 void __init init_irq_proc(void)
979 {
980 #if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
981         struct proc_dir_entry *dir;
982         int irq;
983
984         dir = proc_mkdir("irq", 0);
985         if (!dir)
986                 return;
987
988         for (irq = 0; irq < NR_IRQS; irq++) {
989                 struct proc_dir_entry *entry;
990                 struct irqdesc *desc;
991                 char name[16];
992
993                 desc = irq_desc + irq;
994                 memset(name, 0, sizeof(name));
995                 snprintf(name, sizeof(name) - 1, "%u", irq);
996
997                 desc->procdir = proc_mkdir(name, dir);
998                 if (!desc->procdir)
999                         continue;
1000
1001                 entry = create_proc_entry("smp_affinity", 0600, desc->procdir);
1002                 if (entry) {
1003                         entry->nlink = 1;
1004                         entry->data = (void *)irq;
1005                         entry->read_proc = irq_affinity_read_proc;
1006                         entry->write_proc = irq_affinity_write_proc;
1007                 }
1008         }
1009 #endif
1010 }
1011
1012 void __init init_IRQ(void)
1013 {
1014         struct irqdesc *desc;
1015         extern void init_dma(void);
1016         int irq;
1017
1018 #ifdef CONFIG_SMP
1019         bad_irq_desc.affinity = CPU_MASK_ALL;
1020         bad_irq_desc.cpu = smp_processor_id();
1021 #endif
1022
1023         for (irq = 0, desc = irq_desc; irq < NR_IRQS; irq++, desc++) {
1024                 *desc = bad_irq_desc;
1025                 INIT_LIST_HEAD(&desc->pend);
1026         }
1027
1028         init_arch_irq();
1029         init_dma();
1030 }
1031
1032 static int __init noirqdebug_setup(char *str)
1033 {
1034         noirqdebug = 1;
1035         return 1;
1036 }
1037
1038 __setup("noirqdebug", noirqdebug_setup);