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
  29 #include <asm/system.h>
  30 #include <asm/io.h>
  31 #include <asm/bitops.h>
  32 #include <asm/uaccess.h>
  33
  34 /*
  35  * Controller mappings for all interrupt sources:
  36  */
  37 irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {
  38         [0 ... NR_IRQS-1] = {
  39                 .handler = &no_irq_type,
  40                 .lock = SPIN_LOCK_UNLOCKED
  41         }
  42 };
  43
  44 static void register_irq_proc(unsigned int irq);
  45
  46 volatile unsigned long irq_err_count;
  47
  48 /*
  49  * Special irq handlers.
  50  */
  51
  52 irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs)
  53 {
  54         return IRQ_NONE;
  55 }
  56
  57 /*
  58  * Generic no controller code
  59  */
  60
  61 static void no_irq_enable_disable(unsigned int irq) { }
  62 static unsigned int no_irq_startup(unsigned int irq) { return 0; }
  63
  64 static void
  65 no_irq_ack(unsigned int irq)
  66 {
  67         irq_err_count++;
  68         printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
  69 }
  70
  71 struct hw_interrupt_type no_irq_type = {
  72         .typename       = "none",
  73         .startup        = no_irq_startup,
  74         .shutdown       = no_irq_enable_disable,
  75         .enable         = no_irq_enable_disable,
  76         .disable        = no_irq_enable_disable,
  77         .ack            = no_irq_ack,
  78         .end            = no_irq_enable_disable,
  79 };
  80
  81 int
  82 handle_IRQ_event(unsigned int irq, struct pt_regs *regs,
  83                  struct irqaction *action)
  84 {
  85         int status = 1; /* Force the "do bottom halves" bit */
  86
  87         do {
  88                 if (!(action->flags & SA_INTERRUPT))
  89                         local_irq_enable();
  90                 else
  91                         local_irq_disable();
  92
  93                 status |= action->flags;
  94                 action->handler(irq, action->dev_id, regs);
  95                 action = action->next;
  96         } while (action);
  97         if (status & SA_SAMPLE_RANDOM)
  98                 add_interrupt_randomness(irq);
  99         local_irq_disable();
 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         synchronize_irq(irq);
 133 }
 134
 135 void
 136 enable_irq(unsigned int irq)
 137 {
 138         irq_desc_t *desc = irq_desc + irq;
 139         unsigned long flags;
 140
 141         spin_lock_irqsave(&desc->lock, flags);
 142         switch (desc->depth) {
 143         case 1: {
 144                 unsigned int status = desc->status & ~IRQ_DISABLED;
 145                 desc->status = status;
 146                 if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
 147                         desc->status = status | IRQ_REPLAY;
 148                         hw_resend_irq(desc->handler,irq);
 149                 }
 150                 desc->handler->enable(irq);
 151                 /* fall-through */
 152         }
 153         default:
 154                 desc->depth--;
 155                 break;
 156         case 0:
 157                 printk(KERN_ERR "enable_irq() unbalanced from %p\n",
 158                        __builtin_return_address(0));
 159         }
 160         spin_unlock_irqrestore(&desc->lock, flags);
 161 }
 162
 163 int
 164 setup_irq(unsigned int irq, struct irqaction * new)
 165 {
 166         int shared = 0;
 167         struct irqaction *old, **p;
 168         unsigned long flags;
 169         irq_desc_t *desc = irq_desc + irq;
 170
 171         if (desc->handler == &no_irq_type)
 172                 return -ENOSYS;
 173
 174         /*
 175          * Some drivers like serial.c use request_irq() heavily,
 176          * so we have to be careful not to interfere with a
 177          * running system.
 178          */
 179         if (new->flags & SA_SAMPLE_RANDOM) {
 180                 /*
 181                  * This function might sleep, we want to call it first,
 182                  * outside of the atomic block.
 183                  * Yes, this might clear the entropy pool if the wrong
 184                  * driver is attempted to be loaded, without actually
 185                  * installing a new handler, but is this really a problem,
 186                  * only the sysadmin is able to do this.
 187                  */
 188                 rand_initialize_irq(irq);
 189         }
 190
 191         /*
 192          * The following block of code has to be executed atomically
 193          */
 194         spin_lock_irqsave(&desc->lock,flags);
 195         p = &desc->action;
 196         if ((old = *p) != NULL) {
 197                 /* Can't share interrupts unless both agree to */
 198                 if (!(old->flags & new->flags & SA_SHIRQ)) {
 199                         spin_unlock_irqrestore(&desc->lock,flags);
 200                         return -EBUSY;
 201                 }
 202
 203                 /* add new interrupt at end of irq queue */
 204                 do {
 205                         p = &old->next;
 206                         old = *p;
 207                 } while (old);
 208                 shared = 1;
 209         }
 210
 211         *p = new;
 212
 213         if (!shared) {
 214                 desc->depth = 0;
 215                 desc->status &=
 216                     ~(IRQ_DISABLED|IRQ_AUTODETECT|IRQ_WAITING|IRQ_INPROGRESS);
 217                 desc->handler->startup(irq);
 218         }
 219         spin_unlock_irqrestore(&desc->lock,flags);
 220
 221         return 0;
 222 }
 223
 224 static struct proc_dir_entry * root_irq_dir;
 225 static struct proc_dir_entry * irq_dir[NR_IRQS];
 226
 227 #ifdef CONFIG_SMP
 228 static struct proc_dir_entry * smp_affinity_entry[NR_IRQS];
 229 static char irq_user_affinity[NR_IRQS];
 230 static cpumask_t irq_affinity[NR_IRQS] = { [0 ... NR_IRQS-1] = CPU_MASK_ALL };
 231
 232 static void
 233 select_smp_affinity(int irq)
 234 {
 235         static int last_cpu;
 236         int cpu = last_cpu + 1;
 237
 238         if (! irq_desc[irq].handler->set_affinity || irq_user_affinity[irq])
 239                 return;
 240
 241         while (!cpu_possible(cpu))
 242                 cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
 243         last_cpu = cpu;
 244
 245         irq_affinity[irq] = cpumask_of_cpu(cpu);
 246         irq_desc[irq].handler->set_affinity(irq, cpumask_of_cpu(cpu));
 247 }
 248
 249 static int
 250 irq_affinity_read_proc (char *page, char **start, off_t off,
 251                         int count, int *eof, void *data)
 252 {
 253         int len = cpumask_scnprintf(page, count, irq_affinity[(long)data]);
 254         if (count - len < 2)
 255                 return -EINVAL;
 256         len += sprintf(page + len, "\n");
 257         return len;
 258 }
 259
 260 static int
 261 irq_affinity_write_proc(struct file *file, const char __user *buffer,
 262                         unsigned long count, void *data)
 263 {
 264         int irq = (long) data, full_count = count, err;
 265         cpumask_t new_value;
 266
 267         if (!irq_desc[irq].handler->set_affinity)
 268                 return -EIO;
 269
 270         err = cpumask_parse(buffer, count, new_value);
 271
 272         /* The special value 0 means release control of the
 273            affinity to kernel.  */
 274         cpus_and(new_value, new_value, cpu_online_map);
 275         if (cpus_empty(new_value)) {
 276                 irq_user_affinity[irq] = 0;
 277                 select_smp_affinity(irq);
 278         }
 279         /* Do not allow disabling IRQs completely - it's a too easy
 280            way to make the system unusable accidentally :-) At least
 281            one online CPU still has to be targeted.  */
 282         else {
 283                 irq_affinity[irq] = new_value;
 284                 irq_user_affinity[irq] = 1;
 285                 irq_desc[irq].handler->set_affinity(irq, new_value);
 286         }
 287
 288         return full_count;
 289 }
 290
 291 static int
 292 prof_cpu_mask_read_proc(char *page, char **start, off_t off,
 293                         int count, int *eof, void *data)
 294 {
 295         int len = cpumask_scnprintf(page, count, *(cpumask_t *)data);
 296         if (count - len < 2)
 297                 return -EINVAL;
 298         len += sprintf(page + len, "\n");
 299         return len;
 300 }
 301
 302 static int
 303 prof_cpu_mask_write_proc(struct file *file, const char __user *buffer,
 304                          unsigned long count, void *data)
 305 {
 306         unsigned long full_count = count, err;
 307         cpumask_t new_value, *mask = (cpumask_t *)data;
 308
 309         err = cpumask_parse(buffer, count, new_value);
 310         if (err)
 311                 return err;
 312
 313         *mask = new_value;
 314         return full_count;
 315 }
 316 #endif /* CONFIG_SMP */
 317
 318 #define MAX_NAMELEN 10
 319
 320 static void
 321 register_irq_proc (unsigned int irq)
 322 {
 323         char name [MAX_NAMELEN];
 324
 325         if (!root_irq_dir || (irq_desc[irq].handler == &no_irq_type) ||
 326             irq_dir[irq])
 327                 return;
 328
 329         memset(name, 0, MAX_NAMELEN);
 330         sprintf(name, "%d", irq);
 331
 332         /* create /proc/irq/1234 */
 333         irq_dir[irq] = proc_mkdir(name, root_irq_dir);
 334
 335 #ifdef CONFIG_SMP
 336         if (irq_desc[irq].handler->set_affinity) {
 337                 struct proc_dir_entry *entry;
 338                 /* create /proc/irq/1234/smp_affinity */
 339                 entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
 340
 341                 if (entry) {
 342                         entry->nlink = 1;
 343                         entry->data = (void *)(long)irq;
 344                         entry->read_proc = irq_affinity_read_proc;
 345                         entry->write_proc = irq_affinity_write_proc;
 346                 }
 347
 348                 smp_affinity_entry[irq] = entry;
 349         }
 350 #endif
 351 }
 352
 353 unsigned long prof_cpu_mask = ~0UL;
 354
 355 void
 356 init_irq_proc (void)
 357 {
 358 #ifdef CONFIG_SMP
 359         struct proc_dir_entry *entry;
 360 #endif
 361         int i;
 362
 363         /* create /proc/irq */
 364         root_irq_dir = proc_mkdir("irq", NULL);
 365
 366 #ifdef CONFIG_SMP
 367         /* create /proc/irq/prof_cpu_mask */
 368         entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir);
 369
 370         entry->nlink = 1;
 371         entry->data = (void *)&prof_cpu_mask;
 372         entry->read_proc = prof_cpu_mask_read_proc;
 373         entry->write_proc = prof_cpu_mask_write_proc;
 374 #endif
 375
 376         /*
 377          * Create entries for all existing IRQs.
 378          */
 379         for (i = 0; i < ACTUAL_NR_IRQS; i++) {
 380                 if (irq_desc[i].handler == &no_irq_type)
 381                         continue;
 382                 register_irq_proc(i);
 383         }
 384 }
 385
 386 int
 387 request_irq(unsigned int irq, irqreturn_t (*handler)(int, void *, struct pt_regs *),
 388             unsigned long irqflags, const char * devname, void *dev_id)
 389 {
 390         int retval;
 391         struct irqaction * action;
 392
 393         if (irq >= ACTUAL_NR_IRQS)
 394                 return -EINVAL;
 395         if (!handler)
 396                 return -EINVAL;
 397
 398 #if 1
 399         /*
 400          * Sanity-check: shared interrupts should REALLY pass in
 401          * a real dev-ID, otherwise we'll have trouble later trying
 402          * to figure out which interrupt is which (messes up the
 403          * interrupt freeing logic etc).
 404          */
 405         if ((irqflags & SA_SHIRQ) && !dev_id) {
 406                 printk(KERN_ERR
 407                        "Bad boy: %s (at %p) called us without a dev_id!\n",
 408                        devname, __builtin_return_address(0));
 409         }
 410 #endif
 411
 412         action = (struct irqaction *)
 413                         kmalloc(sizeof(struct irqaction), GFP_KERNEL);
 414         if (!action)
 415                 return -ENOMEM;
 416
 417         action->handler = handler;
 418         action->flags = irqflags;
 419         cpus_clear(action->mask);
 420         action->name = devname;
 421         action->next = NULL;
 422         action->dev_id = dev_id;
 423
 424 #ifdef CONFIG_SMP
 425         select_smp_affinity(irq);
 426 #endif
 427
 428         retval = setup_irq(irq, action);
 429         if (retval)
 430                 kfree(action);
 431         return retval;
 432 }
 433
 434 EXPORT_SYMBOL(request_irq);
 435
 436 void
 437 free_irq(unsigned int irq, void *dev_id)
 438 {
 439         irq_desc_t *desc;
 440         struct irqaction **p;
 441         unsigned long flags;
 442
 443         if (irq >= ACTUAL_NR_IRQS) {
 444                 printk(KERN_CRIT "Trying to free IRQ%d\n", irq);
 445                 return;
 446         }
 447
 448         desc = irq_desc + irq;
 449         spin_lock_irqsave(&desc->lock,flags);
 450         p = &desc->action;
 451         for (;;) {
 452                 struct irqaction * action = *p;
 453                 if (action) {
 454                         struct irqaction **pp = p;
 455                         p = &action->next;
 456                         if (action->dev_id != dev_id)
 457                                 continue;
 458
 459                         /* Found - now remove it from the list of entries.  */
 460                         *pp = action->next;
 461                         if (!desc->action) {
 462                                 desc->status |= IRQ_DISABLED;
 463                                 desc->handler->shutdown(irq);
 464                         }
 465                         spin_unlock_irqrestore(&desc->lock,flags);
 466
 467 #ifdef CONFIG_SMP
 468                         /* Wait to make sure it's not being used on
 469                            another CPU.  */
 470                         while (desc->status & IRQ_INPROGRESS)
 471                                 barrier();
 472 #endif
 473                         kfree(action);
 474                         return;
 475                 }
 476                 printk(KERN_ERR "Trying to free free IRQ%d\n",irq);
 477                 spin_unlock_irqrestore(&desc->lock,flags);
 478                 return;
 479         }
 480 }
 481
 482 EXPORT_SYMBOL(free_irq);
 483
 484 int
 485 show_interrupts(struct seq_file *p, void *v)
 486 {
 487 #ifdef CONFIG_SMP
 488         int j;
 489 #endif
 490         int i = *(loff_t *) v;
 491         struct irqaction * action;
 492         unsigned long flags;
 493
 494 #ifdef CONFIG_SMP
 495         if (i == 0) {
 496                 seq_puts(p, "           ");
 497                 for (i = 0; i < NR_CPUS; i++)
 498                         if (cpu_online(i))
 499                                 seq_printf(p, "CPU%d       ", i);
 500                 seq_putc(p, '\n');
 501         }
 502 #endif
 503
 504         if (i < ACTUAL_NR_IRQS) {
 505                 spin_lock_irqsave(&irq_desc[i].lock, flags);
 506                 action = irq_desc[i].action;
 507                 if (!action)
 508                         goto unlock;
 509                 seq_printf(p, "%3d: ",i);
 510 #ifndef CONFIG_SMP
 511                 seq_printf(p, "%10u ", kstat_irqs(i));
 512 #else
 513                 for (j = 0; j < NR_CPUS; j++)
 514                         if (cpu_online(j))
 515                                 seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
 516 #endif
 517                 seq_printf(p, " %14s", irq_desc[i].handler->typename);
 518                 seq_printf(p, "  %c%s",
 519                         (action->flags & SA_INTERRUPT)?'+':' ',
 520                         action->name);
 521
 522                 for (action=action->next; action; action = action->next) {
 523                         seq_printf(p, ", %c%s",
 524                                   (action->flags & SA_INTERRUPT)?'+':' ',
 525                                    action->name);
 526                 }
 527
 528                 seq_putc(p, '\n');
 529 unlock:
 530                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 531         } else if (i == ACTUAL_NR_IRQS) {
 532 #ifdef CONFIG_SMP
 533                 seq_puts(p, "IPI: ");
 534                 for (i = 0; i < NR_CPUS; i++)
 535                         if (cpu_online(i))
 536                                 seq_printf(p, "%10lu ", cpu_data[i].ipi_count);
 537                 seq_putc(p, '\n');
 538 #endif
 539                 seq_printf(p, "ERR: %10lu\n", irq_err_count);
 540         }
 541         return 0;
 542 }
 543
 544
 545 /*
 546  * handle_irq handles all normal device IRQ's (the special
 547  * SMP cross-CPU interrupts have their own specific
 548  * handlers).
 549  */
 550
 551 #define MAX_ILLEGAL_IRQS 16
 552
 553 void
 554 handle_irq(int irq, struct pt_regs * regs)
 555 {
 556         /*
 557          * We ack quickly, we don't want the irq controller
 558          * thinking we're snobs just because some other CPU has
 559          * disabled global interrupts (we have already done the
 560          * INT_ACK cycles, it's too late to try to pretend to the
 561          * controller that we aren't taking the interrupt).
 562          *
 563          * 0 return value means that this irq is already being
 564          * handled by some other CPU. (or is disabled)
 565          */
 566         int cpu = smp_processor_id();
 567         irq_desc_t *desc = irq_desc + irq;
 568         struct irqaction * action;
 569         unsigned int status;
 570         static unsigned int illegal_count=0;
 571
 572         if ((unsigned) irq > ACTUAL_NR_IRQS && illegal_count < MAX_ILLEGAL_IRQS ) {
 573                 irq_err_count++;
 574                 illegal_count++;
 575                 printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
 576                        irq);
 577                 return;
 578         }
 579
 580         irq_enter();
 581         kstat_cpu(cpu).irqs[irq]++;
 582         spin_lock_irq(&desc->lock); /* mask also the higher prio events */
 583         desc->handler->ack(irq);
 584         /*
 585          * REPLAY is when Linux resends an IRQ that was dropped earlier.
 586          * WAITING is used by probe to mark irqs that are being tested.
 587          */
 588         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 589         status |= IRQ_PENDING; /* we _want_ to handle it */
 590
 591         /*
 592          * If the IRQ is disabled for whatever reason, we cannot
 593          * use the action we have.
 594          */
 595         action = NULL;
 596         if (!(status & (IRQ_DISABLED | IRQ_INPROGRESS))) {
 597                 action = desc->action;
 598                 status &= ~IRQ_PENDING; /* we commit to handling */
 599                 status |= IRQ_INPROGRESS; /* we are handling it */
 600         }
 601         desc->status = status;
 602
 603         /*
 604          * If there is no IRQ handler or it was disabled, exit early.
 605          * Since we set PENDING, if another processor is handling
 606          * a different instance of this same irq, the other processor
 607          * will take care of it.
 608          */
 609         if (!action)
 610                 goto out;
 611
 612         /*
 613          * Edge triggered interrupts need to remember pending events.
 614          * This applies to any hw interrupts that allow a second
 615          * instance of the same irq to arrive while we are in handle_irq
 616          * or in the handler. But the code here only handles the _second_
 617          * instance of the irq, not the third or fourth. So it is mostly
 618          * useful for irq hardware that does not mask cleanly in an
 619          * SMP environment.
 620          */
 621         for (;;) {
 622                 spin_unlock(&desc->lock);
 623                 handle_IRQ_event(irq, regs, action);
 624                 spin_lock(&desc->lock);
 625
 626                 if (!(desc->status & IRQ_PENDING)
 627                     || (desc->status & IRQ_LEVEL))
 628                         break;
 629                 desc->status &= ~IRQ_PENDING;
 630         }
 631         desc->status &= ~IRQ_INPROGRESS;
 632 out:
 633         /*
 634          * The ->end() handler has to deal with interrupts which got
 635          * disabled while the handler was running.
 636          */
 637         desc->handler->end(irq);
 638         spin_unlock(&desc->lock);
 639
 640         irq_exit();
 641 }
 642
 643 /*
 644  * IRQ autodetection code..
 645  *
 646  * This depends on the fact that any interrupt that
 647  * comes in on to an unassigned handler will get stuck
 648  * with "IRQ_WAITING" cleared and the interrupt
 649  * disabled.
 650  */
 651 unsigned long
 652 probe_irq_on(void)
 653 {
 654         int i;
 655         irq_desc_t *desc;
 656         unsigned long delay;
 657         unsigned long val;
 658
 659         /* Something may have generated an irq long ago and we want to
 660            flush such a longstanding irq before considering it as spurious. */
 661         for (i = NR_IRQS-1; i >= 0; i--) {
 662                 desc = irq_desc + i;
 663
 664                 spin_lock_irq(&desc->lock);
 665                 if (!irq_desc[i].action)
 666                         irq_desc[i].handler->startup(i);
 667                 spin_unlock_irq(&desc->lock);
 668         }
 669
 670         /* Wait for longstanding interrupts to trigger. */
 671         for (delay = jiffies + HZ/50; time_after(delay, jiffies); )
 672                 /* about 20ms delay */ barrier();
 673
 674         /* enable any unassigned irqs (we must startup again here because
 675            if a longstanding irq happened in the previous stage, it may have
 676            masked itself) first, enable any unassigned irqs. */
 677         for (i = NR_IRQS-1; i >= 0; i--) {
 678                 desc = irq_desc + i;
 679
 680                 spin_lock_irq(&desc->lock);
 681                 if (!desc->action) {
 682                         desc->status |= IRQ_AUTODETECT | IRQ_WAITING;
 683                         if (desc->handler->startup(i))
 684                                 desc->status |= IRQ_PENDING;
 685                 }
 686                 spin_unlock_irq(&desc->lock);
 687         }
 688
 689         /*
 690          * Wait for spurious interrupts to trigger
 691          */
 692         for (delay = jiffies + HZ/10; time_after(delay, jiffies); )
 693                 /* about 100ms delay */ barrier();
 694
 695         /*
 696          * Now filter out any obviously spurious interrupts
 697          */
 698         val = 0;
 699         for (i=0; i<NR_IRQS; i++) {
 700                 irq_desc_t *desc = irq_desc + i;
 701                 unsigned int status;
 702
 703                 spin_lock_irq(&desc->lock);
 704                 status = desc->status;
 705
 706                 if (status & IRQ_AUTODETECT) {
 707                         /* It triggered already - consider it spurious. */
 708                         if (!(status & IRQ_WAITING)) {
 709                                 desc->status = status & ~IRQ_AUTODETECT;
 710                                 desc->handler->shutdown(i);
 711                         } else
 712                                 if (i < 32)
 713                                         val |= 1 << i;
 714                 }
 715                 spin_unlock_irq(&desc->lock);
 716         }
 717
 718         return val;
 719 }
 720
 721 EXPORT_SYMBOL(probe_irq_on);
 722
 723 /*
 724  * Return a mask of triggered interrupts (this
 725  * can handle only legacy ISA interrupts).
 726  */
 727 unsigned int
 728 probe_irq_mask(unsigned long val)
 729 {
 730         int i;
 731         unsigned int mask;
 732
 733         mask = 0;
 734         for (i = 0; i < NR_IRQS; i++) {
 735                 irq_desc_t *desc = irq_desc + i;
 736                 unsigned int status;
 737
 738                 spin_lock_irq(&desc->lock);
 739                 status = desc->status;
 740
 741                 if (status & IRQ_AUTODETECT) {
 742                         /* We only react to ISA interrupts */
 743                         if (!(status & IRQ_WAITING)) {
 744                                 if (i < 16)
 745                                         mask |= 1 << i;
 746                         }
 747
 748                         desc->status = status & ~IRQ_AUTODETECT;
 749                         desc->handler->shutdown(i);
 750                 }
 751                 spin_unlock_irq(&desc->lock);
 752         }
 753
 754         return mask & val;
 755 }
 756
 757 /*
 758  * Get the result of the IRQ probe.. A negative result means that
 759  * we have several candidates (but we return the lowest-numbered
 760  * one).
 761  */
 762
 763 int
 764 probe_irq_off(unsigned long val)
 765 {
 766         int i, irq_found, nr_irqs;
 767
 768         nr_irqs = 0;
 769         irq_found = 0;
 770         for (i=0; i<NR_IRQS; i++) {
 771                 irq_desc_t *desc = irq_desc + i;
 772                 unsigned int status;
 773
 774                 spin_lock_irq(&desc->lock);
 775                 status = desc->status;
 776
 777                 if (status & IRQ_AUTODETECT) {
 778                         if (!(status & IRQ_WAITING)) {
 779                                 if (!nr_irqs)
 780                                         irq_found = i;
 781                                 nr_irqs++;
 782                         }
 783                         desc->status = status & ~IRQ_AUTODETECT;
 784                         desc->handler->shutdown(i);
 785                 }
 786                 spin_unlock_irq(&desc->lock);
 787         }
 788
 789         if (nr_irqs > 1)
 790                 irq_found = -irq_found;
 791         return irq_found;
 792 }
 793
 794 EXPORT_SYMBOL(probe_irq_off);
 795
 796 #ifdef CONFIG_SMP
 797 void synchronize_irq(unsigned int irq)
 798 {
 799         /* is there anything to synchronize with? */
 800         if (!irq_desc[irq].action)
 801                 return;
 802
 803         while (irq_desc[irq].status & IRQ_INPROGRESS)
 804                 barrier();
 805 }
 806 #endif