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