Linux-2.6.12-rc2
[linux-3.10.git] / arch / alpha / kernel / irq.c
1 /*
2  *      linux/arch/alpha/kernel/irq.c
3  *
4  *      Copyright (C) 1995 Linus Torvalds
5  *
6  * This file contains the code used by various IRQ handling routines:
7  * asking for different IRQ's should be done through these routines
8  * instead of just grabbing them. Thus setups with different IRQ numbers
9  * shouldn't result in any weird surprises, and installing new handlers
10  * should be easier.
11  */
12
13 #include <linux/config.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/errno.h>
17 #include <linux/kernel_stat.h>
18 #include <linux/signal.h>
19 #include <linux/sched.h>
20 #include <linux/ptrace.h>
21 #include <linux/interrupt.h>
22 #include <linux/slab.h>
23 #include <linux/random.h>
24 #include <linux/init.h>
25 #include <linux/irq.h>
26 #include <linux/proc_fs.h>
27 #include <linux/seq_file.h>
28 #include <linux/profile.h>
29 #include <linux/bitops.h>
30
31 #include <asm/system.h>
32 #include <asm/io.h>
33 #include <asm/uaccess.h>
34
35 /*
36  * Controller mappings for all interrupt sources:
37  */
38 irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {
39         [0 ... NR_IRQS-1] = {
40                 .handler = &no_irq_type,
41                 .lock = SPIN_LOCK_UNLOCKED
42         }
43 };
44
45 static void register_irq_proc(unsigned int irq);
46
47 volatile unsigned long irq_err_count;
48
49 /*
50  * Special irq handlers.
51  */
52
53 irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs)
54 {
55         return IRQ_NONE;
56 }
57
58 /*
59  * Generic no controller code
60  */
61
62 static void no_irq_enable_disable(unsigned int irq) { }
63 static unsigned int no_irq_startup(unsigned int irq) { return 0; }
64
65 static void
66 no_irq_ack(unsigned int irq)
67 {
68         irq_err_count++;
69         printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
70 }
71
72 struct hw_interrupt_type no_irq_type = {
73         .typename       = "none",
74         .startup        = no_irq_startup,
75         .shutdown       = no_irq_enable_disable,
76         .enable         = no_irq_enable_disable,
77         .disable        = no_irq_enable_disable,
78         .ack            = no_irq_ack,
79         .end            = no_irq_enable_disable,
80 };
81
82 int
83 handle_IRQ_event(unsigned int irq, struct pt_regs *regs,
84                  struct irqaction *action)
85 {
86         int status = 1; /* Force the "do bottom halves" bit */
87         int ret;
88
89         do {
90                 if (!(action->flags & SA_INTERRUPT))
91                         local_irq_enable();
92                 else
93                         local_irq_disable();
94
95                 ret = action->handler(irq, action->dev_id, regs);
96                 if (ret == IRQ_HANDLED)
97                         status |= action->flags;
98                 action = action->next;
99         } while (action);
100         if (status & SA_SAMPLE_RANDOM)
101                 add_interrupt_randomness(irq);
102         local_irq_disable();
103
104         return status;
105 }
106
107 /*
108  * Generic enable/disable code: this just calls
109  * down into the PIC-specific version for the actual
110  * hardware disable after having gotten the irq
111  * controller lock. 
112  */
113 void inline
114 disable_irq_nosync(unsigned int irq)
115 {
116         irq_desc_t *desc = irq_desc + irq;
117         unsigned long flags;
118
119         spin_lock_irqsave(&desc->lock, flags);
120         if (!desc->depth++) {
121                 desc->status |= IRQ_DISABLED;
122                 desc->handler->disable(irq);
123         }
124         spin_unlock_irqrestore(&desc->lock, flags);
125 }
126
127 /*
128  * Synchronous version of the above, making sure the IRQ is
129  * no longer running on any other IRQ..
130  */
131 void
132 disable_irq(unsigned int irq)
133 {
134         disable_irq_nosync(irq);
135         synchronize_irq(irq);
136 }
137
138 void
139 enable_irq(unsigned int irq)
140 {
141         irq_desc_t *desc = irq_desc + irq;
142         unsigned long flags;
143
144         spin_lock_irqsave(&desc->lock, flags);
145         switch (desc->depth) {
146         case 1: {
147                 unsigned int status = desc->status & ~IRQ_DISABLED;
148                 desc->status = status;
149                 if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
150                         desc->status = status | IRQ_REPLAY;
151                         hw_resend_irq(desc->handler,irq);
152                 }
153                 desc->handler->enable(irq);
154                 /* fall-through */
155         }
156         default:
157                 desc->depth--;
158                 break;
159         case 0:
160                 printk(KERN_ERR "enable_irq() unbalanced from %p\n",
161                        __builtin_return_address(0));
162         }
163         spin_unlock_irqrestore(&desc->lock, flags);
164 }
165
166 int
167 setup_irq(unsigned int irq, struct irqaction * new)
168 {
169         int shared = 0;
170         struct irqaction *old, **p;
171         unsigned long flags;
172         irq_desc_t *desc = irq_desc + irq;
173
174         if (desc->handler == &no_irq_type)
175                 return -ENOSYS;
176
177         /*
178          * Some drivers like serial.c use request_irq() heavily,
179          * so we have to be careful not to interfere with a
180          * running system.
181          */
182         if (new->flags & SA_SAMPLE_RANDOM) {
183                 /*
184                  * This function might sleep, we want to call it first,
185                  * outside of the atomic block.
186                  * Yes, this might clear the entropy pool if the wrong
187                  * driver is attempted to be loaded, without actually
188                  * installing a new handler, but is this really a problem,
189                  * only the sysadmin is able to do this.
190                  */
191                 rand_initialize_irq(irq);
192         }
193
194         /*
195          * The following block of code has to be executed atomically
196          */
197         spin_lock_irqsave(&desc->lock,flags);
198         p = &desc->action;
199         if ((old = *p) != NULL) {
200                 /* Can't share interrupts unless both agree to */
201                 if (!(old->flags & new->flags & SA_SHIRQ)) {
202                         spin_unlock_irqrestore(&desc->lock,flags);
203                         return -EBUSY;
204                 }
205
206                 /* add new interrupt at end of irq queue */
207                 do {
208                         p = &old->next;
209                         old = *p;
210                 } while (old);
211                 shared = 1;
212         }
213
214         *p = new;
215
216         if (!shared) {
217                 desc->depth = 0;
218                 desc->status &=
219                     ~(IRQ_DISABLED|IRQ_AUTODETECT|IRQ_WAITING|IRQ_INPROGRESS);
220                 desc->handler->startup(irq);
221         }
222         spin_unlock_irqrestore(&desc->lock,flags);
223
224         return 0;
225 }
226
227 static struct proc_dir_entry * root_irq_dir;
228 static struct proc_dir_entry * irq_dir[NR_IRQS];
229
230 #ifdef CONFIG_SMP 
231 static struct proc_dir_entry * smp_affinity_entry[NR_IRQS];
232 static char irq_user_affinity[NR_IRQS];
233 static cpumask_t irq_affinity[NR_IRQS] = { [0 ... NR_IRQS-1] = CPU_MASK_ALL };
234
235 static void
236 select_smp_affinity(int irq)
237 {
238         static int last_cpu;
239         int cpu = last_cpu + 1;
240
241         if (! irq_desc[irq].handler->set_affinity || irq_user_affinity[irq])
242                 return;
243
244         while (!cpu_possible(cpu))
245                 cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
246         last_cpu = cpu;
247
248         irq_affinity[irq] = cpumask_of_cpu(cpu);
249         irq_desc[irq].handler->set_affinity(irq, cpumask_of_cpu(cpu));
250 }
251
252 static int
253 irq_affinity_read_proc (char *page, char **start, off_t off,
254                         int count, int *eof, void *data)
255 {
256         int len = cpumask_scnprintf(page, count, irq_affinity[(long)data]);
257         if (count - len < 2)
258                 return -EINVAL;
259         len += sprintf(page + len, "\n");
260         return len;
261 }
262
263 static int
264 irq_affinity_write_proc(struct file *file, const char __user *buffer,
265                         unsigned long count, void *data)
266 {
267         int irq = (long) data, full_count = count, err;
268         cpumask_t new_value;
269
270         if (!irq_desc[irq].handler->set_affinity)
271                 return -EIO;
272
273         err = cpumask_parse(buffer, count, new_value);
274
275         /* The special value 0 means release control of the
276            affinity to kernel.  */
277         cpus_and(new_value, new_value, cpu_online_map);
278         if (cpus_empty(new_value)) {
279                 irq_user_affinity[irq] = 0;
280                 select_smp_affinity(irq);
281         }
282         /* Do not allow disabling IRQs completely - it's a too easy
283            way to make the system unusable accidentally :-) At least
284            one online CPU still has to be targeted.  */
285         else {
286                 irq_affinity[irq] = new_value;
287                 irq_user_affinity[irq] = 1;
288                 irq_desc[irq].handler->set_affinity(irq, new_value);
289         }
290
291         return full_count;
292 }
293
294 #endif /* CONFIG_SMP */
295
296 #define MAX_NAMELEN 10
297
298 static void
299 register_irq_proc (unsigned int irq)
300 {
301         char name [MAX_NAMELEN];
302
303         if (!root_irq_dir || (irq_desc[irq].handler == &no_irq_type) ||
304             irq_dir[irq])
305                 return;
306
307         memset(name, 0, MAX_NAMELEN);
308         sprintf(name, "%d", irq);
309
310         /* create /proc/irq/1234 */
311         irq_dir[irq] = proc_mkdir(name, root_irq_dir);
312
313 #ifdef CONFIG_SMP 
314         if (irq_desc[irq].handler->set_affinity) {
315                 struct proc_dir_entry *entry;
316                 /* create /proc/irq/1234/smp_affinity */
317                 entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
318
319                 if (entry) {
320                         entry->nlink = 1;
321                         entry->data = (void *)(long)irq;
322                         entry->read_proc = irq_affinity_read_proc;
323                         entry->write_proc = irq_affinity_write_proc;
324                 }
325
326                 smp_affinity_entry[irq] = entry;
327         }
328 #endif
329 }
330
331 void
332 init_irq_proc (void)
333 {
334         int i;
335
336         /* create /proc/irq */
337         root_irq_dir = proc_mkdir("irq", NULL);
338
339 #ifdef CONFIG_SMP 
340         /* create /proc/irq/prof_cpu_mask */
341         create_prof_cpu_mask(root_irq_dir);
342 #endif
343
344         /*
345          * Create entries for all existing IRQs.
346          */
347         for (i = 0; i < ACTUAL_NR_IRQS; i++) {
348                 if (irq_desc[i].handler == &no_irq_type)
349                         continue;
350                 register_irq_proc(i);
351         }
352 }
353
354 int
355 request_irq(unsigned int irq, irqreturn_t (*handler)(int, void *, struct pt_regs *),
356             unsigned long irqflags, const char * devname, void *dev_id)
357 {
358         int retval;
359         struct irqaction * action;
360
361         if (irq >= ACTUAL_NR_IRQS)
362                 return -EINVAL;
363         if (!handler)
364                 return -EINVAL;
365
366 #if 1
367         /*
368          * Sanity-check: shared interrupts should REALLY pass in
369          * a real dev-ID, otherwise we'll have trouble later trying
370          * to figure out which interrupt is which (messes up the
371          * interrupt freeing logic etc).
372          */
373         if ((irqflags & SA_SHIRQ) && !dev_id) {
374                 printk(KERN_ERR
375                        "Bad boy: %s (at %p) called us without a dev_id!\n",
376                        devname, __builtin_return_address(0));
377         }
378 #endif
379
380         action = (struct irqaction *)
381                         kmalloc(sizeof(struct irqaction), GFP_KERNEL);
382         if (!action)
383                 return -ENOMEM;
384
385         action->handler = handler;
386         action->flags = irqflags;
387         cpus_clear(action->mask);
388         action->name = devname;
389         action->next = NULL;
390         action->dev_id = dev_id;
391
392 #ifdef CONFIG_SMP
393         select_smp_affinity(irq);
394 #endif
395
396         retval = setup_irq(irq, action);
397         if (retval)
398                 kfree(action);
399         return retval;
400 }
401
402 EXPORT_SYMBOL(request_irq);
403
404 void
405 free_irq(unsigned int irq, void *dev_id)
406 {
407         irq_desc_t *desc;
408         struct irqaction **p;
409         unsigned long flags;
410
411         if (irq >= ACTUAL_NR_IRQS) {
412                 printk(KERN_CRIT "Trying to free IRQ%d\n", irq);
413                 return;
414         }
415
416         desc = irq_desc + irq;
417         spin_lock_irqsave(&desc->lock,flags);
418         p = &desc->action;
419         for (;;) {
420                 struct irqaction * action = *p;
421                 if (action) {
422                         struct irqaction **pp = p;
423                         p = &action->next;
424                         if (action->dev_id != dev_id)
425                                 continue;
426
427                         /* Found - now remove it from the list of entries.  */
428                         *pp = action->next;
429                         if (!desc->action) {
430                                 desc->status |= IRQ_DISABLED;
431                                 desc->handler->shutdown(irq);
432                         }
433                         spin_unlock_irqrestore(&desc->lock,flags);
434
435 #ifdef CONFIG_SMP
436                         /* Wait to make sure it's not being used on
437                            another CPU.  */
438                         while (desc->status & IRQ_INPROGRESS)
439                                 barrier();
440 #endif
441                         kfree(action);
442                         return;
443                 }
444                 printk(KERN_ERR "Trying to free free IRQ%d\n",irq);
445                 spin_unlock_irqrestore(&desc->lock,flags);
446                 return;
447         }
448 }
449
450 EXPORT_SYMBOL(free_irq);
451
452 int
453 show_interrupts(struct seq_file *p, void *v)
454 {
455 #ifdef CONFIG_SMP
456         int j;
457 #endif
458         int i = *(loff_t *) v;
459         struct irqaction * action;
460         unsigned long flags;
461
462 #ifdef CONFIG_SMP
463         if (i == 0) {
464                 seq_puts(p, "           ");
465                 for (i = 0; i < NR_CPUS; i++)
466                         if (cpu_online(i))
467                                 seq_printf(p, "CPU%d       ", i);
468                 seq_putc(p, '\n');
469         }
470 #endif
471
472         if (i < ACTUAL_NR_IRQS) {
473                 spin_lock_irqsave(&irq_desc[i].lock, flags);
474                 action = irq_desc[i].action;
475                 if (!action) 
476                         goto unlock;
477                 seq_printf(p, "%3d: ",i);
478 #ifndef CONFIG_SMP
479                 seq_printf(p, "%10u ", kstat_irqs(i));
480 #else
481                 for (j = 0; j < NR_CPUS; j++)
482                         if (cpu_online(j))
483                                 seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
484 #endif
485                 seq_printf(p, " %14s", irq_desc[i].handler->typename);
486                 seq_printf(p, "  %c%s",
487                         (action->flags & SA_INTERRUPT)?'+':' ',
488                         action->name);
489
490                 for (action=action->next; action; action = action->next) {
491                         seq_printf(p, ", %c%s",
492                                   (action->flags & SA_INTERRUPT)?'+':' ',
493                                    action->name);
494                 }
495
496                 seq_putc(p, '\n');
497 unlock:
498                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
499         } else if (i == ACTUAL_NR_IRQS) {
500 #ifdef CONFIG_SMP
501                 seq_puts(p, "IPI: ");
502                 for (i = 0; i < NR_CPUS; i++)
503                         if (cpu_online(i))
504                                 seq_printf(p, "%10lu ", cpu_data[i].ipi_count);
505                 seq_putc(p, '\n');
506 #endif
507                 seq_printf(p, "ERR: %10lu\n", irq_err_count);
508         }
509         return 0;
510 }
511
512
513 /*
514  * handle_irq handles all normal device IRQ's (the special
515  * SMP cross-CPU interrupts have their own specific
516  * handlers).
517  */
518
519 #define MAX_ILLEGAL_IRQS 16
520
521 void
522 handle_irq(int irq, struct pt_regs * regs)
523 {       
524         /* 
525          * We ack quickly, we don't want the irq controller
526          * thinking we're snobs just because some other CPU has
527          * disabled global interrupts (we have already done the
528          * INT_ACK cycles, it's too late to try to pretend to the
529          * controller that we aren't taking the interrupt).
530          *
531          * 0 return value means that this irq is already being
532          * handled by some other CPU. (or is disabled)
533          */
534         int cpu = smp_processor_id();
535         irq_desc_t *desc = irq_desc + irq;
536         struct irqaction * action;
537         unsigned int status;
538         static unsigned int illegal_count=0;
539         
540         if ((unsigned) irq > ACTUAL_NR_IRQS && illegal_count < MAX_ILLEGAL_IRQS ) {
541                 irq_err_count++;
542                 illegal_count++;
543                 printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
544                        irq);
545                 return;
546         }
547
548         irq_enter();
549         kstat_cpu(cpu).irqs[irq]++;
550         spin_lock_irq(&desc->lock); /* mask also the higher prio events */
551         desc->handler->ack(irq);
552         /*
553          * REPLAY is when Linux resends an IRQ that was dropped earlier.
554          * WAITING is used by probe to mark irqs that are being tested.
555          */
556         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
557         status |= IRQ_PENDING; /* we _want_ to handle it */
558
559         /*
560          * If the IRQ is disabled for whatever reason, we cannot
561          * use the action we have.
562          */
563         action = NULL;
564         if (!(status & (IRQ_DISABLED | IRQ_INPROGRESS))) {
565                 action = desc->action;
566                 status &= ~IRQ_PENDING; /* we commit to handling */
567                 status |= IRQ_INPROGRESS; /* we are handling it */
568         }
569         desc->status = status;
570
571         /*
572          * If there is no IRQ handler or it was disabled, exit early.
573          * Since we set PENDING, if another processor is handling
574          * a different instance of this same irq, the other processor
575          * will take care of it.
576          */
577         if (!action)
578                 goto out;
579
580         /*
581          * Edge triggered interrupts need to remember pending events.
582          * This applies to any hw interrupts that allow a second
583          * instance of the same irq to arrive while we are in handle_irq
584          * or in the handler. But the code here only handles the _second_
585          * instance of the irq, not the third or fourth. So it is mostly
586          * useful for irq hardware that does not mask cleanly in an
587          * SMP environment.
588          */
589         for (;;) {
590                 spin_unlock(&desc->lock);
591                 handle_IRQ_event(irq, regs, action);
592                 spin_lock(&desc->lock);
593                 
594                 if (!(desc->status & IRQ_PENDING)
595                     || (desc->status & IRQ_LEVEL))
596                         break;
597                 desc->status &= ~IRQ_PENDING;
598         }
599         desc->status &= ~IRQ_INPROGRESS;
600 out:
601         /*
602          * The ->end() handler has to deal with interrupts which got
603          * disabled while the handler was running.
604          */
605         desc->handler->end(irq);
606         spin_unlock(&desc->lock);
607
608         irq_exit();
609 }
610
611 /*
612  * IRQ autodetection code..
613  *
614  * This depends on the fact that any interrupt that
615  * comes in on to an unassigned handler will get stuck
616  * with "IRQ_WAITING" cleared and the interrupt
617  * disabled.
618  */
619 unsigned long
620 probe_irq_on(void)
621 {
622         int i;
623         irq_desc_t *desc;
624         unsigned long delay;
625         unsigned long val;
626
627         /* Something may have generated an irq long ago and we want to
628            flush such a longstanding irq before considering it as spurious. */
629         for (i = NR_IRQS-1; i >= 0; i--) {
630                 desc = irq_desc + i;
631
632                 spin_lock_irq(&desc->lock);
633                 if (!irq_desc[i].action) 
634                         irq_desc[i].handler->startup(i);
635                 spin_unlock_irq(&desc->lock);
636         }
637
638         /* Wait for longstanding interrupts to trigger. */
639         for (delay = jiffies + HZ/50; time_after(delay, jiffies); )
640                 /* about 20ms delay */ barrier();
641
642         /* enable any unassigned irqs (we must startup again here because
643            if a longstanding irq happened in the previous stage, it may have
644            masked itself) first, enable any unassigned irqs. */
645         for (i = NR_IRQS-1; i >= 0; i--) {
646                 desc = irq_desc + i;
647
648                 spin_lock_irq(&desc->lock);
649                 if (!desc->action) {
650                         desc->status |= IRQ_AUTODETECT | IRQ_WAITING;
651                         if (desc->handler->startup(i))
652                                 desc->status |= IRQ_PENDING;
653                 }
654                 spin_unlock_irq(&desc->lock);
655         }
656
657         /*
658          * Wait for spurious interrupts to trigger
659          */
660         for (delay = jiffies + HZ/10; time_after(delay, jiffies); )
661                 /* about 100ms delay */ barrier();
662
663         /*
664          * Now filter out any obviously spurious interrupts
665          */
666         val = 0;
667         for (i=0; i<NR_IRQS; i++) {
668                 irq_desc_t *desc = irq_desc + i;
669                 unsigned int status;
670
671                 spin_lock_irq(&desc->lock);
672                 status = desc->status;
673
674                 if (status & IRQ_AUTODETECT) {
675                         /* It triggered already - consider it spurious. */
676                         if (!(status & IRQ_WAITING)) {
677                                 desc->status = status & ~IRQ_AUTODETECT;
678                                 desc->handler->shutdown(i);
679                         } else
680                                 if (i < 32)
681                                         val |= 1 << i;
682                 }
683                 spin_unlock_irq(&desc->lock);
684         }
685
686         return val;
687 }
688
689 EXPORT_SYMBOL(probe_irq_on);
690
691 /*
692  * Return a mask of triggered interrupts (this
693  * can handle only legacy ISA interrupts).
694  */
695 unsigned int
696 probe_irq_mask(unsigned long val)
697 {
698         int i;
699         unsigned int mask;
700
701         mask = 0;
702         for (i = 0; i < NR_IRQS; i++) {
703                 irq_desc_t *desc = irq_desc + i;
704                 unsigned int status;
705
706                 spin_lock_irq(&desc->lock);
707                 status = desc->status;
708
709                 if (status & IRQ_AUTODETECT) {
710                         /* We only react to ISA interrupts */
711                         if (!(status & IRQ_WAITING)) {
712                                 if (i < 16)
713                                         mask |= 1 << i;
714                         }
715
716                         desc->status = status & ~IRQ_AUTODETECT;
717                         desc->handler->shutdown(i);
718                 }
719                 spin_unlock_irq(&desc->lock);
720         }
721
722         return mask & val;
723 }
724
725 /*
726  * Get the result of the IRQ probe.. A negative result means that
727  * we have several candidates (but we return the lowest-numbered
728  * one).
729  */
730
731 int
732 probe_irq_off(unsigned long val)
733 {
734         int i, irq_found, nr_irqs;
735
736         nr_irqs = 0;
737         irq_found = 0;
738         for (i=0; i<NR_IRQS; i++) {
739                 irq_desc_t *desc = irq_desc + i;
740                 unsigned int status;
741
742                 spin_lock_irq(&desc->lock);
743                 status = desc->status;
744
745                 if (status & IRQ_AUTODETECT) {
746                         if (!(status & IRQ_WAITING)) {
747                                 if (!nr_irqs)
748                                         irq_found = i;
749                                 nr_irqs++;
750                         }
751                         desc->status = status & ~IRQ_AUTODETECT;
752                         desc->handler->shutdown(i);
753                 }
754                 spin_unlock_irq(&desc->lock);
755         }
756
757         if (nr_irqs > 1)
758                 irq_found = -irq_found;
759         return irq_found;
760 }
761
762 EXPORT_SYMBOL(probe_irq_off);
763
764 #ifdef CONFIG_SMP
765 void synchronize_irq(unsigned int irq)
766 {
767         /* is there anything to synchronize with? */
768         if (!irq_desc[irq].action)
769                 return;
770
771         while (irq_desc[irq].status & IRQ_INPROGRESS)
772                 barrier();
773 }
774 #endif