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Linux/arch/alpha/kernel/irq.c

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  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/ptrace.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/interrupt.h>
 21 #include <linux/slab.h>
 22 #include <linux/random.h>
 23 #include <linux/init.h>
 24 #include <linux/irq.h>
 25 #include <linux/proc_fs.h>
 26 
 27 #include <asm/system.h>
 28 #include <asm/io.h>
 29 #include <asm/bitops.h>
 30 #include <asm/uaccess.h>
 31 
 32 /*
 33  * Controller mappings for all interrupt sources:
 34  */
 35 irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {
 36         [0 ... NR_IRQS-1] = { 0, &no_irq_type, NULL, 0, SPIN_LOCK_UNLOCKED}
 37 };
 38 
 39 static void register_irq_proc(unsigned int irq);
 40 
 41 volatile unsigned long irq_err_count;
 42 
 43 /*
 44  * Special irq handlers.
 45  */
 46 
 47 void no_action(int cpl, void *dev_id, struct pt_regs *regs) { }
 48 
 49 /*
 50  * Generic no controller code
 51  */
 52 
 53 static void no_irq_enable_disable(unsigned int irq) { }
 54 static unsigned int no_irq_startup(unsigned int irq) { return 0; }
 55 
 56 static void
 57 no_irq_ack(unsigned int irq)
 58 {
 59         irq_err_count++;
 60         printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
 61 }
 62 
 63 struct hw_interrupt_type no_irq_type = {
 64         typename:       "none",
 65         startup:        no_irq_startup,
 66         shutdown:       no_irq_enable_disable,
 67         enable:         no_irq_enable_disable,
 68         disable:        no_irq_enable_disable,
 69         ack:            no_irq_ack,
 70         end:            no_irq_enable_disable,
 71 };
 72 
 73 int
 74 handle_IRQ_event(unsigned int irq, struct pt_regs *regs,
 75                  struct irqaction *action)
 76 {
 77         int status;
 78         int cpu = smp_processor_id();
 79 
 80         kstat.irqs[cpu][irq]++;
 81         irq_enter(cpu, irq);
 82 
 83         status = 1;     /* Force the "do bottom halves" bit */
 84 
 85         do {
 86                 if (!(action->flags & SA_INTERRUPT))
 87                         __sti();
 88                 else
 89                         __cli();
 90 
 91                 status |= action->flags;
 92                 action->handler(irq, action->dev_id, regs);
 93                 action = action->next;
 94         } while (action);
 95         if (status & SA_SAMPLE_RANDOM)
 96                 add_interrupt_randomness(irq);
 97         __cli();
 98 
 99         irq_exit(cpu, irq);
100 
101         return status;
102 }
103 
104 /*
105  * Generic enable/disable code: this just calls
106  * down into the PIC-specific version for the actual
107  * hardware disable after having gotten the irq
108  * controller lock. 
109  */
110 void inline
111 disable_irq_nosync(unsigned int irq)
112 {
113         irq_desc_t *desc = irq_desc + irq;
114         unsigned long flags;
115 
116         spin_lock_irqsave(&desc->lock, flags);
117         if (!desc->depth++) {
118                 desc->status |= IRQ_DISABLED;
119                 desc->handler->disable(irq);
120         }
121         spin_unlock_irqrestore(&desc->lock, flags);
122 }
123 
124 /*
125  * Synchronous version of the above, making sure the IRQ is
126  * no longer running on any other IRQ..
127  */
128 void
129 disable_irq(unsigned int irq)
130 {
131         disable_irq_nosync(irq);
132 
133         if (!local_irq_count(smp_processor_id())) {
134                 do {
135                         barrier();
136                 } while (irq_desc[irq].status & IRQ_INPROGRESS);
137         }
138 }
139 
140 void
141 enable_irq(unsigned int irq)
142 {
143         irq_desc_t *desc = irq_desc + irq;
144         unsigned long flags;
145 
146         spin_lock_irqsave(&desc->lock, flags);
147         switch (desc->depth) {
148         case 1: {
149                 unsigned int status = desc->status & ~IRQ_DISABLED;
150                 desc->status = status;
151                 if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
152                         desc->status = status | IRQ_REPLAY;
153                         hw_resend_irq(desc->handler,irq);
154                 }
155                 desc->handler->enable(irq);
156                 /* fall-through */
157         }
158         default:
159                 desc->depth--;
160                 break;
161         case 0:
162                 printk(KERN_ERR "enable_irq() unbalanced from %p\n",
163                        __builtin_return_address(0));
164         }
165         spin_unlock_irqrestore(&desc->lock, flags);
166 }
167 
168 int
169 setup_irq(unsigned int irq, struct irqaction * new)
170 {
171         int shared = 0;
172         struct irqaction *old, **p;
173         unsigned long flags;
174         irq_desc_t *desc = irq_desc + irq;
175 
176         /*
177          * Some drivers like serial.c use request_irq() heavily,
178          * so we have to be careful not to interfere with a
179          * running system.
180          */
181         if (new->flags & SA_SAMPLE_RANDOM) {
182                 /*
183                  * This function might sleep, we want to call it first,
184                  * outside of the atomic block.
185                  * Yes, this might clear the entropy pool if the wrong
186                  * driver is attempted to be loaded, without actually
187                  * installing a new handler, but is this really a problem,
188                  * only the sysadmin is able to do this.
189                  */
190                 rand_initialize_irq(irq);
191         }
192 
193         /*
194          * The following block of code has to be executed atomically
195          */
196         spin_lock_irqsave(&desc->lock,flags);
197         p = &desc->action;
198         if ((old = *p) != NULL) {
199                 /* Can't share interrupts unless both agree to */
200                 if (!(old->flags & new->flags & SA_SHIRQ)) {
201                         spin_unlock_irqrestore(&desc->lock,flags);
202                         return -EBUSY;
203                 }
204 
205                 /* add new interrupt at end of irq queue */
206                 do {
207                         p = &old->next;
208                         old = *p;
209                 } while (old);
210                 shared = 1;
211         }
212 
213         *p = new;
214 
215         if (!shared) {
216                 desc->depth = 0;
217                 desc->status &= ~(IRQ_DISABLED | IRQ_INPROGRESS);
218                 desc->handler->startup(irq);
219         }
220         spin_unlock_irqrestore(&desc->lock,flags);
221 
222         return 0;
223 }
224 
225 static struct proc_dir_entry * root_irq_dir;
226 static struct proc_dir_entry * irq_dir[NR_IRQS];
227 
228 #ifdef CONFIG_SMP
229 static struct proc_dir_entry * smp_affinity_entry[NR_IRQS];
230 static char irq_user_affinity[NR_IRQS];
231 static unsigned long irq_affinity[NR_IRQS] = { [0 ... NR_IRQS-1] = ~0UL };
232 
233 static void
234 select_smp_affinity(int irq)
235 {
236         static int last_cpu;
237         int cpu = last_cpu + 1;
238 
239         if (! irq_desc[irq].handler->set_affinity || irq_user_affinity[irq])
240                 return;
241 
242         while (((cpu_present_mask >> cpu) & 1) == 0)
243                 cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
244         last_cpu = cpu;
245 
246         irq_affinity[irq] = 1UL << cpu;
247         irq_desc[irq].handler->set_affinity(irq, 1UL << cpu);
248 }
249 
250 #define HEX_DIGITS 16
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         if (count < HEX_DIGITS+1)
257                 return -EINVAL;
258         return sprintf (page, "%016lx\n", irq_affinity[(long)data]);
259 }
260 
261 static unsigned int
262 parse_hex_value (const char *buffer,
263                  unsigned long count, unsigned long *ret)
264 {
265         unsigned char hexnum [HEX_DIGITS];
266         unsigned long value;
267         int i;
268 
269         if (!count)
270                 return -EINVAL;
271         if (count > HEX_DIGITS)
272                 count = HEX_DIGITS;
273         if (copy_from_user(hexnum, buffer, count))
274                 return -EFAULT;
275 
276         /*
277          * Parse the first 8 characters as a hex string, any non-hex char
278          * is end-of-string. '00e1', 'e1', '00E1', 'E1' are all the same.
279          */
280         value = 0;
281 
282         for (i = 0; i < count; i++) {
283                 unsigned int c = hexnum[i];
284 
285                 switch (c) {
286                         case '' ... '9': c -= ''; break;
287                         case 'a' ... 'f': c -= 'a'-10; break;
288                         case 'A' ... 'F': c -= 'A'-10; break;
289                 default:
290                         goto out;
291                 }
292                 value = (value << 4) | c;
293         }
294 out:
295         *ret = value;
296         return 0;
297 }
298 
299 static int
300 irq_affinity_write_proc(struct file *file, const char *buffer,
301                         unsigned long count, void *data)
302 {
303         int irq = (long) data, full_count = count, err;
304         unsigned long new_value;
305 
306         if (!irq_desc[irq].handler->set_affinity)
307                 return -EIO;
308 
309         err = parse_hex_value(buffer, count, &new_value);
310 
311         /* The special value 0 means release control of the
312            affinity to kernel.  */
313         if (new_value == 0) {
314                 irq_user_affinity[irq] = 0;
315                 select_smp_affinity(irq);
316         }
317         /* Do not allow disabling IRQs completely - it's a too easy
318            way to make the system unusable accidentally :-) At least
319            one online CPU still has to be targeted.  */
320         else if (!(new_value & cpu_present_mask))
321                 return -EINVAL;
322         else {
323                 irq_affinity[irq] = new_value;
324                 irq_user_affinity[irq] = 1;
325                 irq_desc[irq].handler->set_affinity(irq, new_value);
326         }
327 
328         return full_count;
329 }
330 
331 static int
332 prof_cpu_mask_read_proc(char *page, char **start, off_t off,
333                         int count, int *eof, void *data)
334 {
335         unsigned long *mask = (unsigned long *) data;
336         if (count < HEX_DIGITS+1)
337                 return -EINVAL;
338         return sprintf (page, "%016lx\n", *mask);
339 }
340 
341 static int
342 prof_cpu_mask_write_proc(struct file *file, const char *buffer,
343                          unsigned long count, void *data)
344 {
345         unsigned long *mask = (unsigned long *) data, full_count = count, err;
346         unsigned long new_value;
347 
348         err = parse_hex_value(buffer, count, &new_value);
349         if (err)
350                 return err;
351 
352         *mask = new_value;
353         return full_count;
354 }
355 #endif /* CONFIG_SMP */
356 
357 #define MAX_NAMELEN 10
358 
359 static void
360 register_irq_proc (unsigned int irq)
361 {
362 #ifdef CONFIG_SMP
363         struct proc_dir_entry *entry;
364 #endif
365         char name [MAX_NAMELEN];
366 
367         if (!root_irq_dir || (irq_desc[irq].handler == &no_irq_type))
368                 return;
369 
370         memset(name, 0, MAX_NAMELEN);
371         sprintf(name, "%d", irq);
372 
373         /* create /proc/irq/1234 */
374         irq_dir[irq] = proc_mkdir(name, root_irq_dir);
375 
376 #ifdef CONFIG_SMP
377         if (irq_desc[irq].handler->set_affinity) {
378                 /* create /proc/irq/1234/smp_affinity */
379                 entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
380 
381                 entry->nlink = 1;
382                 entry->data = (void *)(long)irq;
383                 entry->read_proc = irq_affinity_read_proc;
384                 entry->write_proc = irq_affinity_write_proc;
385 
386                 smp_affinity_entry[irq] = entry;
387         }
388 #endif
389 }
390 
391 unsigned long prof_cpu_mask = ~0UL;
392 
393 void
394 init_irq_proc (void)
395 {
396 #ifdef CONFIG_SMP
397         struct proc_dir_entry *entry;
398 #endif
399         int i;
400 
401         /* create /proc/irq */
402         root_irq_dir = proc_mkdir("irq", 0);
403 
404 #ifdef CONFIG_SMP
405         /* create /proc/irq/prof_cpu_mask */
406         entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir);
407 
408         entry->nlink = 1;
409         entry->data = (void *)&prof_cpu_mask;
410         entry->read_proc = prof_cpu_mask_read_proc;
411         entry->write_proc = prof_cpu_mask_write_proc;
412 #endif
413 
414         /*
415          * Create entries for all existing IRQs. If the number of IRQs
416          * is greater the 1/4 the total dynamic inode space for /proc,
417          * don't pollute the inode space
418          */
419         if (ACTUAL_NR_IRQS < (PROC_NDYNAMIC / 4)) {
420                 for (i = 0; i < ACTUAL_NR_IRQS; i++) {
421                         if (irq_desc[i].handler == &no_irq_type)
422                                 continue;
423                         register_irq_proc(i);
424                 }
425         }
426 }
427 
428 int
429 request_irq(unsigned int irq, void (*handler)(int, void *, struct pt_regs *),
430             unsigned long irqflags, const char * devname, void *dev_id)
431 {
432         int retval;
433         struct irqaction * action;
434 
435         if (irq >= ACTUAL_NR_IRQS)
436                 return -EINVAL;
437         if (!handler)
438                 return -EINVAL;
439 
440 #if 1
441         /*
442          * Sanity-check: shared interrupts should REALLY pass in
443          * a real dev-ID, otherwise we'll have trouble later trying
444          * to figure out which interrupt is which (messes up the
445          * interrupt freeing logic etc).
446          */
447         if ((irqflags & SA_SHIRQ) && !dev_id) {
448                 printk(KERN_ERR
449                        "Bad boy: %s (at %p) called us without a dev_id!\n",
450                        devname, __builtin_return_address(0));
451         }
452 #endif
453 
454         action = (struct irqaction *)
455                         kmalloc(sizeof(struct irqaction), GFP_KERNEL);
456         if (!action)
457                 return -ENOMEM;
458 
459         action->handler = handler;
460         action->flags = irqflags;
461         action->mask = 0;
462         action->name = devname;
463         action->next = NULL;
464         action->dev_id = dev_id;
465 
466 #ifdef CONFIG_SMP
467         select_smp_affinity(irq);
468 #endif
469 
470         retval = setup_irq(irq, action);
471         if (retval)
472                 kfree(action);
473         return retval;
474 }
475 
476 void
477 free_irq(unsigned int irq, void *dev_id)
478 {
479         irq_desc_t *desc;
480         struct irqaction **p;
481         unsigned long flags;
482 
483         if (irq >= ACTUAL_NR_IRQS) {
484                 printk(KERN_CRIT "Trying to free IRQ%d\n", irq);
485                 return;
486         }
487 
488         desc = irq_desc + irq;
489         spin_lock_irqsave(&desc->lock,flags);
490         p = &desc->action;
491         for (;;) {
492                 struct irqaction * action = *p;
493                 if (action) {
494                         struct irqaction **pp = p;
495                         p = &action->next;
496                         if (action->dev_id != dev_id)
497                                 continue;
498 
499                         /* Found - now remove it from the list of entries.  */
500                         *pp = action->next;
501                         if (!desc->action) {
502                                 desc->status |= IRQ_DISABLED;
503                                 desc->handler->shutdown(irq);
504                         }
505                         spin_unlock_irqrestore(&desc->lock,flags);
506 
507 #ifdef CONFIG_SMP
508                         /* Wait to make sure it's not being used on
509                            another CPU.  */
510                         while (desc->status & IRQ_INPROGRESS)
511                                 barrier();
512 #endif
513                         kfree(action);
514                         return;
515                 }
516                 printk(KERN_ERR "Trying to free free IRQ%d\n",irq);
517                 spin_unlock_irqrestore(&desc->lock,flags);
518                 return;
519         }
520 }
521 
522 int
523 get_irq_list(char *buf)
524 {
525 #ifdef CONFIG_SMP
526         int j;
527 #endif
528         int i;
529         struct irqaction * action;
530         char *p = buf;
531 
532 #ifdef CONFIG_SMP
533         p += sprintf(p, "           ");
534         for (i = 0; i < smp_num_cpus; i++)
535                 p += sprintf(p, "CPU%d       ", i);
536 #ifdef DO_BROADCAST_INTS
537         for (i = 0; i < smp_num_cpus; i++)
538                 p += sprintf(p, "TRY%d       ", i);
539 #endif
540         *p++ = '\n';
541 #endif
542 
543         for (i = 0; i < ACTUAL_NR_IRQS; i++) {
544                 action = irq_desc[i].action;
545                 if (!action) 
546                         continue;
547                 p += sprintf(p, "%3d: ",i);
548 #ifndef CONFIG_SMP
549                 p += sprintf(p, "%10u ", kstat_irqs(i));
550 #else
551                 for (j = 0; j < smp_num_cpus; j++)
552                         p += sprintf(p, "%10u ",
553                                      kstat.irqs[cpu_logical_map(j)][i]);
554 #ifdef DO_BROADCAST_INTS
555                 for (j = 0; j < smp_num_cpus; j++)
556                         p += sprintf(p, "%10lu ",
557                                      irq_attempt(cpu_logical_map(j), i));
558 #endif
559 #endif
560                 p += sprintf(p, " %14s", irq_desc[i].handler->typename);
561                 p += sprintf(p, "  %c%s",
562                              (action->flags & SA_INTERRUPT)?'+':' ',
563                              action->name);
564 
565                 for (action=action->next; action; action = action->next) {
566                         p += sprintf(p, ", %c%s",
567                                      (action->flags & SA_INTERRUPT)?'+':' ',
568                                      action->name);
569                 }
570                 *p++ = '\n';
571         }
572 #if CONFIG_SMP
573         p += sprintf(p, "IPI: ");
574         for (j = 0; j < smp_num_cpus; j++)
575                 p += sprintf(p, "%10lu ",
576                              cpu_data[cpu_logical_map(j)].ipi_count);
577         p += sprintf(p, "\n");
578 #endif
579         p += sprintf(p, "ERR: %10lu\n", irq_err_count);
580         return p - buf;
581 }
582 
583 
584 /*
585  * handle_irq handles all normal device IRQ's (the special
586  * SMP cross-CPU interrupts have their own specific
587  * handlers).
588  */
589 
590 #define MAX_ILLEGAL_IRQS 16
591 
592 void
593 handle_irq(int irq, struct pt_regs * regs)
594 {       
595         /* 
596          * We ack quickly, we don't want the irq controller
597          * thinking we're snobs just because some other CPU has
598          * disabled global interrupts (we have already done the
599          * INT_ACK cycles, it's too late to try to pretend to the
600          * controller that we aren't taking the interrupt).
601          *
602          * 0 return value means that this irq is already being
603          * handled by some other CPU. (or is disabled)
604          */
605         int cpu = smp_processor_id();
606         irq_desc_t *desc = irq_desc + irq;
607         struct irqaction * action;
608         unsigned int status;
609         static unsigned int illegal_count=0;
610         
611         if ((unsigned) irq > ACTUAL_NR_IRQS && illegal_count < MAX_ILLEGAL_IRQS ) {
612                 irq_err_count++;
613                 illegal_count++;
614                 printk(KERN_CRIT "device_interrupt: illegal interrupt %d\n",
615                        irq);
616                 return;
617         }
618 
619         irq_attempt(cpu, irq)++;
620         spin_lock_irq(&desc->lock); /* mask also the higher prio events */
621         desc->handler->ack(irq);
622         /*
623          * REPLAY is when Linux resends an IRQ that was dropped earlier.
624          * WAITING is used by probe to mark irqs that are being tested.
625          */
626         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
627         status |= IRQ_PENDING; /* we _want_ to handle it */
628 
629         /*
630          * If the IRQ is disabled for whatever reason, we cannot
631          * use the action we have.
632          */
633         action = NULL;
634         if (!(status & (IRQ_DISABLED | IRQ_INPROGRESS))) {
635                 action = desc->action;
636                 status &= ~IRQ_PENDING; /* we commit to handling */
637                 status |= IRQ_INPROGRESS; /* we are handling it */
638         }
639         desc->status = status;
640 
641         /*
642          * If there is no IRQ handler or it was disabled, exit early.
643          * Since we set PENDING, if another processor is handling
644          * a different instance of this same irq, the other processor
645          * will take care of it.
646          */
647         if (!action)
648                 goto out;
649 
650         /*
651          * Edge triggered interrupts need to remember pending events.
652          * This applies to any hw interrupts that allow a second
653          * instance of the same irq to arrive while we are in handle_irq
654          * or in the handler. But the code here only handles the _second_
655          * instance of the irq, not the third or fourth. So it is mostly
656          * useful for irq hardware that does not mask cleanly in an
657          * SMP environment.
658          */
659         for (;;) {
660                 spin_unlock(&desc->lock);
661                 handle_IRQ_event(irq, regs, action);
662                 spin_lock(&desc->lock);
663                 
664                 if (!(desc->status & IRQ_PENDING)
665                     || (desc->status & IRQ_LEVEL))
666                         break;
667                 desc->status &= ~IRQ_PENDING;
668         }
669         desc->status &= ~IRQ_INPROGRESS;
670 out:
671         /*
672          * The ->end() handler has to deal with interrupts which got
673          * disabled while the handler was running.
674          */
675         desc->handler->end(irq);
676         spin_unlock(&desc->lock);
677 
678         if (softirq_pending(cpu))
679                 do_softirq();
680 }
681 
682 /*
683  * IRQ autodetection code..
684  *
685  * This depends on the fact that any interrupt that
686  * comes in on to an unassigned handler will get stuck
687  * with "IRQ_WAITING" cleared and the interrupt
688  * disabled.
689  */
690 unsigned long
691 probe_irq_on(void)
692 {
693         int i;
694         irq_desc_t *desc;
695         unsigned long delay;
696         unsigned long val;
697 
698         /* Something may have generated an irq long ago and we want to
699            flush such a longstanding irq before considering it as spurious. */
700         for (i = NR_IRQS-1; i >= 0; i--) {
701                 desc = irq_desc + i;
702 
703                 spin_lock_irq(&desc->lock);
704                 if (!irq_desc[i].action) 
705                         irq_desc[i].handler->startup(i);
706                 spin_unlock_irq(&desc->lock);
707         }
708 
709         /* Wait for longstanding interrupts to trigger. */
710         for (delay = jiffies + HZ/50; time_after(delay, jiffies); )
711                 /* about 20ms delay */ synchronize_irq();
712 
713         /* enable any unassigned irqs (we must startup again here because
714            if a longstanding irq happened in the previous stage, it may have
715            masked itself) first, enable any unassigned irqs. */
716         for (i = NR_IRQS-1; i >= 0; i--) {
717                 desc = irq_desc + i;
718 
719                 spin_lock_irq(&desc->lock);
720                 if (!desc->action) {
721                         desc->status |= IRQ_AUTODETECT | IRQ_WAITING;
722                         if (desc->handler->startup(i))
723                                 desc->status |= IRQ_PENDING;
724                 }
725                 spin_unlock_irq(&desc->lock);
726         }
727 
728         /*
729          * Wait for spurious interrupts to trigger
730          */
731         for (delay = jiffies + HZ/10; time_after(delay, jiffies); )
732                 /* about 100ms delay */ synchronize_irq();
733 
734         /*
735          * Now filter out any obviously spurious interrupts
736          */
737         val = 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                         /* It triggered already - consider it spurious. */
747                         if (!(status & IRQ_WAITING)) {
748                                 desc->status = status & ~IRQ_AUTODETECT;
749                                 desc->handler->shutdown(i);
750                         } else
751                                 if (i < 32)
752                                         val |= 1 << i;
753                 }
754                 spin_unlock_irq(&desc->lock);
755         }
756 
757         return val;
758 }
759 
760 /*
761  * Return a mask of triggered interrupts (this
762  * can handle only legacy ISA interrupts).
763  */
764 unsigned int
765 probe_irq_mask(unsigned long val)
766 {
767         int i;
768         unsigned int mask;
769 
770         mask = 0;
771         for (i = 0; i < NR_IRQS; i++) {
772                 irq_desc_t *desc = irq_desc + i;
773                 unsigned int status;
774 
775                 spin_lock_irq(&desc->lock);
776                 status = desc->status;
777 
778                 if (status & IRQ_AUTODETECT) {
779                         /* We only react to ISA interrupts */
780                         if (!(status & IRQ_WAITING)) {
781                                 if (i < 16)
782                                         mask |= 1 << i;
783                         }
784 
785                         desc->status = status & ~IRQ_AUTODETECT;
786                         desc->handler->shutdown(i);
787                 }
788                 spin_unlock_irq(&desc->lock);
789         }
790 
791         return mask & val;
792 }
793 
794 /*
795  * Get the result of the IRQ probe.. A negative result means that
796  * we have several candidates (but we return the lowest-numbered
797  * one).
798  */
799 
800 int
801 probe_irq_off(unsigned long val)
802 {
803         int i, irq_found, nr_irqs;
804 
805         nr_irqs = 0;
806         irq_found = 0;
807         for (i=0; i<NR_IRQS; i++) {
808                 irq_desc_t *desc = irq_desc + i;
809                 unsigned int status;
810 
811                 spin_lock_irq(&desc->lock);
812                 status = desc->status;
813 
814                 if (status & IRQ_AUTODETECT) {
815                         if (!(status & IRQ_WAITING)) {
816                                 if (!nr_irqs)
817                                         irq_found = i;
818                                 nr_irqs++;
819                         }
820                         desc->status = status & ~IRQ_AUTODETECT;
821                         desc->handler->shutdown(i);
822                 }
823                 spin_unlock_irq(&desc->lock);
824         }
825 
826         if (nr_irqs > 1)
827                 irq_found = -irq_found;
828         return irq_found;
829 }
830 

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