arch/um/kernel/irq.c

   1 /*
   2  * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  * Derived (i.e. mostly copied) from arch/i386/kernel/irq.c:
   5  *      Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
   6  */
   7
   8 #include "linux/config.h"
   9 #include "linux/kernel.h"
  10 #include "linux/module.h"
  11 #include "linux/smp.h"
  12 #include "linux/irq.h"
  13 #include "linux/kernel_stat.h"
  14 #include "linux/interrupt.h"
  15 #include "linux/random.h"
  16 #include "linux/slab.h"
  17 #include "linux/file.h"
  18 #include "linux/proc_fs.h"
  19 #include "linux/init.h"
  20 #include "linux/seq_file.h"
  21 #include "asm/irq.h"
  22 #include "asm/hw_irq.h"
  23 #include "asm/hardirq.h"
  24 #include "asm/atomic.h"
  25 #include "asm/signal.h"
  26 #include "asm/system.h"
  27 #include "asm/errno.h"
  28 #include "asm/uaccess.h"
  29 #include "user_util.h"
  30 #include "kern_util.h"
  31 #include "irq_user.h"
  32 #include "irq_kern.h"
  33
  34 static void register_irq_proc (unsigned int irq);
  35
  36 irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {
  37         [0 ... NR_IRQS-1] = {
  38                 .handler = &no_irq_type,
  39                 .lock = SPIN_LOCK_UNLOCKED
  40         }
  41 };
  42
  43 /*
  44  * Generic no controller code
  45  */
  46
  47 static void enable_none(unsigned int irq) { }
  48 static unsigned int startup_none(unsigned int irq) { return 0; }
  49 static void disable_none(unsigned int irq) { }
  50 static void ack_none(unsigned int irq)
  51 {
  52 /*
  53  * 'what should we do if we get a hw irq event on an illegal vector'.
  54  * each architecture has to answer this themselves, it doesn't deserve
  55  * a generic callback i think.
  56  */
  57 #ifdef CONFIG_X86
  58         printk(KERN_ERR "unexpected IRQ trap at vector %02x\n", irq);
  59 #ifdef CONFIG_X86_LOCAL_APIC
  60         /*
  61          * Currently unexpected vectors happen only on SMP and APIC.
  62          * We _must_ ack these because every local APIC has only N
  63          * irq slots per priority level, and a 'hanging, unacked' IRQ
  64          * holds up an irq slot - in excessive cases (when multiple
  65          * unexpected vectors occur) that might lock up the APIC
  66          * completely.
  67          */
  68         ack_APIC_irq();
  69 #endif
  70 #endif
  71 }
  72
  73 /* startup is the same as "enable", shutdown is same as "disable" */
  74 #define shutdown_none   disable_none
  75 #define end_none        enable_none
  76
  77 struct hw_interrupt_type no_irq_type = {
  78         "none",
  79         startup_none,
  80         shutdown_none,
  81         enable_none,
  82         disable_none,
  83         ack_none,
  84         end_none
  85 };
  86
  87 /*
  88  * Generic, controller-independent functions:
  89  */
  90
  91 int show_interrupts(struct seq_file *p, void *v)
  92 {
  93         int i = *(loff_t *) v, j;
  94         struct irqaction * action;
  95         unsigned long flags;
  96
  97         if (i == 0) {
  98                 seq_printf(p, "           ");
  99                 for (j=0; j<NR_CPUS; j++)
 100                         if (cpu_online(j))
 101                                 seq_printf(p, "CPU%d       ",j);
 102                 seq_putc(p, '\n');
 103         }
 104
 105         if (i < NR_IRQS) {
 106                 spin_lock_irqsave(&irq_desc[i].lock, flags);
 107                 action = irq_desc[i].action;
 108                 if (!action)
 109                         goto skip;
 110                 seq_printf(p, "%3d: ",i);
 111 #ifndef CONFIG_SMP
 112                 seq_printf(p, "%10u ", kstat_irqs(i));
 113 #else
 114                 for (j = 0; j < NR_CPUS; j++)
 115                         if (cpu_online(j))
 116                                 seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
 117 #endif
 118                 seq_printf(p, " %14s", irq_desc[i].handler->typename);
 119                 seq_printf(p, "  %s", action->name);
 120
 121                 for (action=action->next; action; action = action->next)
 122                         seq_printf(p, ", %s", action->name);
 123
 124                 seq_putc(p, '\n');
 125 skip:
 126                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
 127         } else if (i == NR_IRQS) {
 128                 seq_printf(p, "NMI: ");
 129                 for (j = 0; j < NR_CPUS; j++)
 130                         if (cpu_online(j))
 131                                 seq_printf(p, "%10u ", nmi_count(j));
 132                 seq_putc(p, '\n');
 133         }
 134
 135         return 0;
 136 }
 137
 138 /*
 139  * This should really return information about whether
 140  * we should do bottom half handling etc. Right now we
 141  * end up _always_ checking the bottom half, which is a
 142  * waste of time and is not what some drivers would
 143  * prefer.
 144  */
 145 int handle_IRQ_event(unsigned int irq, struct pt_regs * regs,
 146                      struct irqaction * action)
 147 {
 148         int status = 1; /* Force the "do bottom halves" bit */
 149
 150         if (!(action->flags & SA_INTERRUPT))
 151                 local_irq_enable();
 152
 153         do {
 154                 status |= action->flags;
 155                 action->handler(irq, action->dev_id, regs);
 156                 action = action->next;
 157         } while (action);
 158         if (status & SA_SAMPLE_RANDOM)
 159                 add_interrupt_randomness(irq);
 160
 161         local_irq_disable();
 162
 163         return status;
 164 }
 165
 166 /*
 167  * Generic enable/disable code: this just calls
 168  * down into the PIC-specific version for the actual
 169  * hardware disable after having gotten the irq
 170  * controller lock.
 171  */
 172
 173 /**
 174  *      disable_irq_nosync - disable an irq without waiting
 175  *      @irq: Interrupt to disable
 176  *
 177  *      Disable the selected interrupt line. Disables of an interrupt
 178  *      stack. Unlike disable_irq(), this function does not ensure existing
 179  *      instances of the IRQ handler have completed before returning.
 180  *
 181  *      This function may be called from IRQ context.
 182  */
 183
 184 inline void disable_irq_nosync(unsigned int irq)
 185 {
 186         irq_desc_t *desc = irq_desc + irq;
 187         unsigned long flags;
 188
 189         spin_lock_irqsave(&desc->lock, flags);
 190         if (!desc->depth++) {
 191                 desc->status |= IRQ_DISABLED;
 192                 desc->handler->disable(irq);
 193         }
 194         spin_unlock_irqrestore(&desc->lock, flags);
 195 }
 196
 197 #ifdef CONFIG_SMP
 198 inline void synchronize_irq(unsigned int irq)
 199 {
 200         /* is there anything to synchronize with? */
 201         if (!irq_desc[irq].action)
 202                 return;
 203
 204         while (irq_desc[irq].status & IRQ_INPROGRESS)
 205                 cpu_relax();
 206 }
 207 #endif
 208
 209 /**
 210  *      disable_irq - disable an irq and wait for completion
 211  *      @irq: Interrupt to disable
 212  *
 213  *      Disable the selected interrupt line. Disables of an interrupt
 214  *      stack. That is for two disables you need two enables. This
 215  *      function waits for any pending IRQ handlers for this interrupt
 216  *      to complete before returning. If you use this function while
 217  *      holding a resource the IRQ handler may need you will deadlock.
 218  *
 219  *      This function may be called - with care - from IRQ context.
 220  */
 221
 222 void disable_irq(unsigned int irq)
 223 {
 224         disable_irq_nosync(irq);
 225         synchronize_irq(irq);
 226 }
 227
 228 /**
 229  *      enable_irq - enable interrupt handling on an irq
 230  *      @irq: Interrupt to enable
 231  *
 232  *      Re-enables the processing of interrupts on this IRQ line
 233  *      providing no disable_irq calls are now in effect.
 234  *
 235  *      This function may be called from IRQ context.
 236  */
 237
 238 void enable_irq(unsigned int irq)
 239 {
 240         irq_desc_t *desc = irq_desc + irq;
 241         unsigned long flags;
 242
 243         spin_lock_irqsave(&desc->lock, flags);
 244         switch (desc->depth) {
 245         case 1: {
 246                 unsigned int status = desc->status & ~IRQ_DISABLED;
 247                 desc->status = status;
 248                 if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
 249                         desc->status = status | IRQ_REPLAY;
 250                         hw_resend_irq(desc->handler,irq);
 251                 }
 252                 desc->handler->enable(irq);
 253                 /* fall-through */
 254         }
 255         default:
 256                 desc->depth--;
 257                 break;
 258         case 0:
 259                 printk(KERN_ERR "enable_irq() unbalanced from %p\n",
 260                        __builtin_return_address(0));
 261         }
 262         spin_unlock_irqrestore(&desc->lock, flags);
 263 }
 264
 265 /*
 266  * do_IRQ handles all normal device IRQ's (the special
 267  * SMP cross-CPU interrupts have their own specific
 268  * handlers).
 269  */
 270 unsigned int do_IRQ(int irq, union uml_pt_regs *regs)
 271 {
 272         /*
 273          * 0 return value means that this irq is already being
 274          * handled by some other CPU. (or is disabled)
 275          */
 276         irq_desc_t *desc = irq_desc + irq;
 277         struct irqaction * action;
 278         unsigned int status;
 279
 280         irq_enter();
 281         kstat_this_cpu.irqs[irq]++;
 282         spin_lock(&desc->lock);
 283         desc->handler->ack(irq);
 284         /*
 285            REPLAY is when Linux resends an IRQ that was dropped earlier
 286            WAITING is used by probe to mark irqs that are being tested
 287            */
 288         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 289         status |= IRQ_PENDING; /* we _want_ to handle it */
 290
 291         /*
 292          * If the IRQ is disabled for whatever reason, we cannot
 293          * use the action we have.
 294          */
 295         action = NULL;
 296         if (!(status & (IRQ_DISABLED | IRQ_INPROGRESS))) {
 297                 action = desc->action;
 298                 status &= ~IRQ_PENDING; /* we commit to handling */
 299                 status |= IRQ_INPROGRESS; /* we are handling it */
 300         }
 301         desc->status = status;
 302
 303         /*
 304          * If there is no IRQ handler or it was disabled, exit early.
 305            Since we set PENDING, if another processor is handling
 306            a different instance of this same irq, the other processor
 307            will take care of it.
 308          */
 309         if (!action)
 310                 goto out;
 311
 312         /*
 313          * Edge triggered interrupts need to remember
 314          * pending events.
 315          * This applies to any hw interrupts that allow a second
 316          * instance of the same irq to arrive while we are in do_IRQ
 317          * or in the handler. But the code here only handles the _second_
 318          * instance of the irq, not the third or fourth. So it is mostly
 319          * useful for irq hardware that does not mask cleanly in an
 320          * SMP environment.
 321          */
 322         for (;;) {
 323                 spin_unlock(&desc->lock);
 324                 handle_IRQ_event(irq, (struct pt_regs *) regs, action);
 325                 spin_lock(&desc->lock);
 326
 327                 if (!(desc->status & IRQ_PENDING))
 328                         break;
 329                 desc->status &= ~IRQ_PENDING;
 330         }
 331         desc->status &= ~IRQ_INPROGRESS;
 332 out:
 333         /*
 334          * The ->end() handler has to deal with interrupts which got
 335          * disabled while the handler was running.
 336          */
 337         desc->handler->end(irq);
 338         spin_unlock(&desc->lock);
 339
 340         irq_exit();
 341
 342         return 1;
 343 }
 344
 345 /**
 346  *      request_irq - allocate an interrupt line
 347  *      @irq: Interrupt line to allocate
 348  *      @handler: Function to be called when the IRQ occurs
 349  *      @irqflags: Interrupt type flags
 350  *      @devname: An ascii name for the claiming device
 351  *      @dev_id: A cookie passed back to the handler function
 352  *
 353  *      This call allocates interrupt resources and enables the
 354  *      interrupt line and IRQ handling. From the point this
 355  *      call is made your handler function may be invoked. Since
 356  *      your handler function must clear any interrupt the board
 357  *      raises, you must take care both to initialise your hardware
 358  *      and to set up the interrupt handler in the right order.
 359  *
 360  *      Dev_id must be globally unique. Normally the address of the
 361  *      device data structure is used as the cookie. Since the handler
 362  *      receives this value it makes sense to use it.
 363  *
 364  *      If your interrupt is shared you must pass a non NULL dev_id
 365  *      as this is required when freeing the interrupt.
 366  *
 367  *      Flags:
 368  *
 369  *      SA_SHIRQ                Interrupt is shared
 370  *
 371  *      SA_INTERRUPT            Disable local interrupts while processing
 372  *
 373  *      SA_SAMPLE_RANDOM        The interrupt can be used for entropy
 374  *
 375  */
 376
 377 int request_irq(unsigned int irq,
 378                 irqreturn_t (*handler)(int, void *, struct pt_regs *),
 379                 unsigned long irqflags,
 380                 const char * devname,
 381                 void *dev_id)
 382 {
 383         int retval;
 384         struct irqaction * action;
 385
 386 #if 1
 387         /*
 388          * Sanity-check: shared interrupts should REALLY pass in
 389          * a real dev-ID, otherwise we'll have trouble later trying
 390          * to figure out which interrupt is which (messes up the
 391          * interrupt freeing logic etc).
 392          */
 393         if (irqflags & SA_SHIRQ) {
 394                 if (!dev_id)
 395                         printk(KERN_ERR "Bad boy: %s (at 0x%x) called us "
 396                                "without a dev_id!\n", devname, (&irq)[-1]);
 397         }
 398 #endif
 399
 400         if (irq >= NR_IRQS)
 401                 return -EINVAL;
 402         if (!handler)
 403                 return -EINVAL;
 404
 405         action = (struct irqaction *)
 406                         kmalloc(sizeof(struct irqaction), GFP_KERNEL);
 407         if (!action)
 408                 return -ENOMEM;
 409
 410         action->handler = handler;
 411         action->flags = irqflags;
 412         action->mask = 0;
 413         action->name = devname;
 414         action->next = NULL;
 415         action->dev_id = dev_id;
 416
 417         retval = setup_irq(irq, action);
 418         if (retval)
 419                 kfree(action);
 420         return retval;
 421 }
 422
 423 EXPORT_SYMBOL(request_irq);
 424
 425 int um_request_irq(unsigned int irq, int fd, int type,
 426                    irqreturn_t (*handler)(int, void *, struct pt_regs *),
 427                    unsigned long irqflags, const char * devname,
 428                    void *dev_id)
 429 {
 430         int err;
 431
 432         err = request_irq(irq, handler, irqflags, devname, dev_id);
 433         if(err)
 434                 return(err);
 435
 436         if(fd != -1)
 437                 err = activate_fd(irq, fd, type, dev_id);
 438         return(err);
 439 }
 440
 441 /* this was setup_x86_irq but it seems pretty generic */
 442 int setup_irq(unsigned int irq, struct irqaction * new)
 443 {
 444         int shared = 0;
 445         unsigned long flags;
 446         struct irqaction *old, **p;
 447         irq_desc_t *desc = irq_desc + irq;
 448
 449         /*
 450          * Some drivers like serial.c use request_irq() heavily,
 451          * so we have to be careful not to interfere with a
 452          * running system.
 453          */
 454         if (new->flags & SA_SAMPLE_RANDOM) {
 455                 /*
 456                  * This function might sleep, we want to call it first,
 457                  * outside of the atomic block.
 458                  * Yes, this might clear the entropy pool if the wrong
 459                  * driver is attempted to be loaded, without actually
 460                  * installing a new handler, but is this really a problem,
 461                  * only the sysadmin is able to do this.
 462                  */
 463                 rand_initialize_irq(irq);
 464         }
 465
 466         /*
 467          * The following block of code has to be executed atomically
 468          */
 469         spin_lock_irqsave(&desc->lock,flags);
 470         p = &desc->action;
 471         old = *p;
 472         if (old != NULL) {
 473                 /* Can't share interrupts unless both agree to */
 474                 if (!(old->flags & new->flags & SA_SHIRQ)) {
 475                         spin_unlock_irqrestore(&desc->lock,flags);
 476                         return -EBUSY;
 477                 }
 478
 479                 /* add new interrupt at end of irq queue */
 480                 do {
 481                         p = &old->next;
 482                         old = *p;
 483                 } while (old);
 484                 shared = 1;
 485         }
 486
 487         *p = new;
 488
 489         if (!shared) {
 490                 desc->depth = 0;
 491                 desc->status &= ~IRQ_DISABLED;
 492                 desc->handler->startup(irq);
 493         }
 494         spin_unlock_irqrestore(&desc->lock,flags);
 495
 496         register_irq_proc(irq);
 497         return 0;
 498 }
 499
 500 /**
 501  *      free_irq - free an interrupt
 502  *      @irq: Interrupt line to free
 503  *      @dev_id: Device identity to free
 504  *
 505  *      Remove an interrupt handler. The handler is removed and if the
 506  *      interrupt line is no longer in use by any driver it is disabled.
 507  *      On a shared IRQ the caller must ensure the interrupt is disabled
 508  *      on the card it drives before calling this function. The function
 509  *      does not return until any executing interrupts for this IRQ
 510  *      have completed.
 511  *
 512  *      This function may be called from interrupt context.
 513  *
 514  *      Bugs: Attempting to free an irq in a handler for the same irq hangs
 515  *            the machine.
 516  */
 517
 518 void free_irq(unsigned int irq, void *dev_id)
 519 {
 520         irq_desc_t *desc;
 521         struct irqaction **p;
 522         unsigned long flags;
 523
 524         if (irq >= NR_IRQS)
 525                 return;
 526
 527         desc = irq_desc + irq;
 528         spin_lock_irqsave(&desc->lock,flags);
 529         p = &desc->action;
 530         for (;;) {
 531                 struct irqaction * action = *p;
 532                 if (action) {
 533                         struct irqaction **pp = p;
 534                         p = &action->next;
 535                         if (action->dev_id != dev_id)
 536                                 continue;
 537
 538                         /* Found it - now remove it from the list of entries */
 539                         *pp = action->next;
 540                         if (!desc->action) {
 541                                 desc->status |= IRQ_DISABLED;
 542                                 desc->handler->shutdown(irq);
 543                         }
 544                         free_irq_by_irq_and_dev(irq, dev_id);
 545                         spin_unlock_irqrestore(&desc->lock,flags);
 546
 547                         /* Wait to make sure it's not being used on another CPU */
 548                         synchronize_irq(irq);
 549                         kfree(action);
 550                         return;
 551                 }
 552                 printk(KERN_ERR "Trying to free free IRQ%d\n",irq);
 553                 spin_unlock_irqrestore(&desc->lock,flags);
 554                 return;
 555         }
 556 }
 557
 558 EXPORT_SYMBOL(free_irq);
 559
 560 /* These are initialized by sysctl_init, which is called from init/main.c */
 561 static struct proc_dir_entry * root_irq_dir;
 562 static struct proc_dir_entry * irq_dir [NR_IRQS];
 563 static struct proc_dir_entry * smp_affinity_entry [NR_IRQS];
 564
 565 /* These are read and written as longs, so a read won't see a partial write
 566  * even during a race.
 567  */
 568 static cpumask_t irq_affinity [NR_IRQS] = { [0 ... NR_IRQS-1] = CPU_MASK_ALL };
 569
 570 static int irq_affinity_read_proc (char *page, char **start, off_t off,
 571                         int count, int *eof, void *data)
 572 {
 573         int len = cpumask_scnprintf(page, count, irq_affinity[(long)data]);
 574         if (count - len < 2)
 575                 return -EINVAL;
 576         len += sprintf(page + len, "\n");
 577         return len;
 578 }
 579
 580 static int irq_affinity_write_proc (struct file *file, const char *buffer,
 581                                         unsigned long count, void *data)
 582 {
 583         int irq = (long) data, full_count = count, err;
 584         cpumask_t new_value;
 585
 586         if (!irq_desc[irq].handler->set_affinity)
 587                 return -EIO;
 588
 589         err = cpumask_parse(buffer, count, new_value);
 590         if(err)
 591                 return(err);
 592
 593 #ifdef CONFIG_SMP
 594         /*
 595          * Do not allow disabling IRQs completely - it's a too easy
 596          * way to make the system unusable accidentally :-) At least
 597          * one online CPU still has to be targeted.
 598          */
 599         { cpumask_t tmp;
 600           cpus_and(tmp, new_value, cpu_online_map);
 601           if (cpus_empty(tmp))
 602                   return -EINVAL;
 603         }
 604 #endif
 605
 606         irq_affinity[irq] = new_value;
 607         irq_desc[irq].handler->set_affinity(irq, new_value);
 608
 609         return full_count;
 610 }
 611
 612 static int prof_cpu_mask_read_proc (char *page, char **start, off_t off,
 613                         int count, int *eof, void *data)
 614 {
 615         int len = cpumask_scnprintf(page, count, *(cpumask_t *)data);
 616         if (count - len < 2)
 617                 return -EINVAL;
 618         len += sprintf(page + len, "\n");
 619         return len;
 620 }
 621
 622 static int prof_cpu_mask_write_proc (struct file *file, const char *buffer,
 623                                         unsigned long count, void *data)
 624 {
 625         cpumask_t *mask = (cpumask_t *)data, new_value;
 626         unsigned long full_count = count, err;
 627
 628         err = cpumask_parse(buffer, count, new_value);
 629         if (err)
 630                 return err;
 631
 632         *mask = new_value;
 633         return full_count;
 634 }
 635
 636 #define MAX_NAMELEN 10
 637
 638 static void register_irq_proc (unsigned int irq)
 639 {
 640         struct proc_dir_entry *entry;
 641         char name [MAX_NAMELEN];
 642
 643         if (!root_irq_dir || (irq_desc[irq].handler == &no_irq_type) ||
 644             irq_dir[irq])
 645                 return;
 646
 647         memset(name, 0, MAX_NAMELEN);
 648         sprintf(name, "%d", irq);
 649
 650         /* create /proc/irq/1234 */
 651         irq_dir[irq] = proc_mkdir(name, root_irq_dir);
 652
 653         /* create /proc/irq/1234/smp_affinity */
 654         entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
 655
 656         entry->nlink = 1;
 657         entry->data = (void *)(long)irq;
 658         entry->read_proc = irq_affinity_read_proc;
 659         entry->write_proc = irq_affinity_write_proc;
 660
 661         smp_affinity_entry[irq] = entry;
 662 }
 663
 664 /* Read and written as a long */
 665 cpumask_t prof_cpu_mask = CPU_MASK_ALL;
 666
 667 void __init init_irq_proc (void)
 668 {
 669         struct proc_dir_entry *entry;
 670         int i;
 671
 672         /* create /proc/irq */
 673         root_irq_dir = proc_mkdir("irq", 0);
 674
 675         /* create /proc/irq/prof_cpu_mask */
 676         entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir);
 677
 678         entry->nlink = 1;
 679         entry->data = (void *)&prof_cpu_mask;
 680         entry->read_proc = prof_cpu_mask_read_proc;
 681         entry->write_proc = prof_cpu_mask_write_proc;
 682
 683         /*
 684          * Create entries for all existing IRQs.
 685          */
 686         for (i = 0; i < NR_IRQS; i++)
 687                 register_irq_proc(i);
 688 }
 689
 690 static spinlock_t irq_spinlock = SPIN_LOCK_UNLOCKED;
 691
 692 unsigned long irq_lock(void)
 693 {
 694         unsigned long flags;
 695
 696         spin_lock_irqsave(&irq_spinlock, flags);
 697         return(flags);
 698 }
 699
 700 void irq_unlock(unsigned long flags)
 701 {
 702         spin_unlock_irqrestore(&irq_spinlock, flags);
 703 }
 704
 705 unsigned long probe_irq_on(void)
 706 {
 707         return(0);
 708 }
 709
 710 EXPORT_SYMBOL(probe_irq_on);
 711
 712 int probe_irq_off(unsigned long val)
 713 {
 714         return(0);
 715 }
 716
 717 EXPORT_SYMBOL(probe_irq_off);
 718
 719 static unsigned int startup_SIGIO_irq(unsigned int irq)
 720 {
 721         return(0);
 722 }
 723
 724 static void shutdown_SIGIO_irq(unsigned int irq)
 725 {
 726 }
 727
 728 static void enable_SIGIO_irq(unsigned int irq)
 729 {
 730 }
 731
 732 static void disable_SIGIO_irq(unsigned int irq)
 733 {
 734 }
 735
 736 static void mask_and_ack_SIGIO(unsigned int irq)
 737 {
 738 }
 739
 740 static void end_SIGIO_irq(unsigned int irq)
 741 {
 742 }
 743
 744 static unsigned int startup_SIGVTALRM_irq(unsigned int irq)
 745 {
 746         return(0);
 747 }
 748
 749 static void shutdown_SIGVTALRM_irq(unsigned int irq)
 750 {
 751 }
 752
 753 static void enable_SIGVTALRM_irq(unsigned int irq)
 754 {
 755 }
 756
 757 static void disable_SIGVTALRM_irq(unsigned int irq)
 758 {
 759 }
 760
 761 static void mask_and_ack_SIGVTALRM(unsigned int irq)
 762 {
 763 }
 764
 765 static void end_SIGVTALRM_irq(unsigned int irq)
 766 {
 767 }
 768
 769 static struct hw_interrupt_type SIGIO_irq_type = {
 770         "SIGIO",
 771         startup_SIGIO_irq,
 772         shutdown_SIGIO_irq,
 773         enable_SIGIO_irq,
 774         disable_SIGIO_irq,
 775         mask_and_ack_SIGIO,
 776         end_SIGIO_irq,
 777         NULL
 778 };
 779
 780 static struct hw_interrupt_type SIGVTALRM_irq_type = {
 781         "SIGVTALRM",
 782         startup_SIGVTALRM_irq,
 783         shutdown_SIGVTALRM_irq,
 784         enable_SIGVTALRM_irq,
 785         disable_SIGVTALRM_irq,
 786         mask_and_ack_SIGVTALRM,
 787         end_SIGVTALRM_irq,
 788         NULL
 789 };
 790
 791 void __init init_IRQ(void)
 792 {
 793         int i;
 794
 795         irq_desc[TIMER_IRQ].status = IRQ_DISABLED;
 796         irq_desc[TIMER_IRQ].action = 0;
 797         irq_desc[TIMER_IRQ].depth = 1;
 798         irq_desc[TIMER_IRQ].handler = &SIGVTALRM_irq_type;
 799         enable_irq(TIMER_IRQ);
 800         for(i=1;i<NR_IRQS;i++){
 801                 irq_desc[i].status = IRQ_DISABLED;
 802                 irq_desc[i].action = 0;
 803                 irq_desc[i].depth = 1;
 804                 irq_desc[i].handler = &SIGIO_irq_type;
 805                 enable_irq(i);
 806         }
 807         init_irq_signals(0);
 808 }
 809
 810 /*
 811  * Overrides for Emacs so that we follow Linus's tabbing style.
 812  * Emacs will notice this stuff at the end of the file and automatically
 813  * adjust the settings for this buffer only.  This must remain at the end
 814  * of the file.
 815  * ---------------------------------------------------------------------------
 816  * Local variables:
 817  * c-file-style: "linux"
 818  * End:
 819  */