kernel/irq/chip.c

   1 /*
   2  * linux/kernel/irq/chip.c
   3  *
   4  * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
   5  * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
   6  *
   7  * This file contains the core interrupt handling code, for irq-chip
   8  * based architectures.
   9  *
  10  * Detailed information is available in Documentation/DocBook/genericirq
  11  */
  12
  13 #include <linux/irq.h>
  14 #include <linux/msi.h>
  15 #include <linux/module.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/kernel_stat.h>
  18
  19 #include "internals.h"
  20
  21 static void dynamic_irq_init_x(unsigned int irq, bool keep_chip_data)
  22 {
  23         struct irq_desc *desc;
  24         unsigned long flags;
  25
  26         desc = irq_to_desc(irq);
  27         if (!desc) {
  28                 WARN(1, KERN_ERR "Trying to initialize invalid IRQ%d\n", irq);
  29                 return;
  30         }
  31
  32         /* Ensure we don't have left over values from a previous use of this irq */
  33         raw_spin_lock_irqsave(&desc->lock, flags);
  34         desc->status = IRQ_DISABLED;
  35         desc->chip = &no_irq_chip;
  36         desc->handle_irq = handle_bad_irq;
  37         desc->depth = 1;
  38         desc->msi_desc = NULL;
  39         desc->handler_data = NULL;
  40         if (!keep_chip_data)
  41                 desc->chip_data = NULL;
  42         desc->action = NULL;
  43         desc->irq_count = 0;
  44         desc->irqs_unhandled = 0;
  45 #ifdef CONFIG_SMP
  46         cpumask_setall(desc->affinity);
  47 #ifdef CONFIG_GENERIC_PENDING_IRQ
  48         cpumask_clear(desc->pending_mask);
  49 #endif
  50 #endif
  51         raw_spin_unlock_irqrestore(&desc->lock, flags);
  52 }
  53
  54 /**
  55  *      dynamic_irq_init - initialize a dynamically allocated irq
  56  *      @irq:   irq number to initialize
  57  */
  58 void dynamic_irq_init(unsigned int irq)
  59 {
  60         dynamic_irq_init_x(irq, false);
  61 }
  62
  63 /**
  64  *      dynamic_irq_init_keep_chip_data - initialize a dynamically allocated irq
  65  *      @irq:   irq number to initialize
  66  *
  67  *      does not set irq_to_desc(irq)->chip_data to NULL
  68  */
  69 void dynamic_irq_init_keep_chip_data(unsigned int irq)
  70 {
  71         dynamic_irq_init_x(irq, true);
  72 }
  73
  74 static void dynamic_irq_cleanup_x(unsigned int irq, bool keep_chip_data)
  75 {
  76         struct irq_desc *desc = irq_to_desc(irq);
  77         unsigned long flags;
  78
  79         if (!desc) {
  80                 WARN(1, KERN_ERR "Trying to cleanup invalid IRQ%d\n", irq);
  81                 return;
  82         }
  83
  84         raw_spin_lock_irqsave(&desc->lock, flags);
  85         if (desc->action) {
  86                 raw_spin_unlock_irqrestore(&desc->lock, flags);
  87                 WARN(1, KERN_ERR "Destroying IRQ%d without calling free_irq\n",
  88                         irq);
  89                 return;
  90         }
  91         desc->msi_desc = NULL;
  92         desc->handler_data = NULL;
  93         if (!keep_chip_data)
  94                 desc->chip_data = NULL;
  95         desc->handle_irq = handle_bad_irq;
  96         desc->chip = &no_irq_chip;
  97         desc->name = NULL;
  98         clear_kstat_irqs(desc);
  99         raw_spin_unlock_irqrestore(&desc->lock, flags);
 100 }
 101
 102 /**
 103  *      dynamic_irq_cleanup - cleanup a dynamically allocated irq
 104  *      @irq:   irq number to initialize
 105  */
 106 void dynamic_irq_cleanup(unsigned int irq)
 107 {
 108         dynamic_irq_cleanup_x(irq, false);
 109 }
 110
 111 /**
 112  *      dynamic_irq_cleanup_keep_chip_data - cleanup a dynamically allocated irq
 113  *      @irq:   irq number to initialize
 114  *
 115  *      does not set irq_to_desc(irq)->chip_data to NULL
 116  */
 117 void dynamic_irq_cleanup_keep_chip_data(unsigned int irq)
 118 {
 119         dynamic_irq_cleanup_x(irq, true);
 120 }
 121
 122
 123 /**
 124  *      set_irq_chip - set the irq chip for an irq
 125  *      @irq:   irq number
 126  *      @chip:  pointer to irq chip description structure
 127  */
 128 int set_irq_chip(unsigned int irq, struct irq_chip *chip)
 129 {
 130         struct irq_desc *desc = irq_to_desc(irq);
 131         unsigned long flags;
 132
 133         if (!desc) {
 134                 WARN(1, KERN_ERR "Trying to install chip for IRQ%d\n", irq);
 135                 return -EINVAL;
 136         }
 137
 138         if (!chip)
 139                 chip = &no_irq_chip;
 140
 141         raw_spin_lock_irqsave(&desc->lock, flags);
 142         irq_chip_set_defaults(chip);
 143         desc->chip = chip;
 144         raw_spin_unlock_irqrestore(&desc->lock, flags);
 145
 146         return 0;
 147 }
 148 EXPORT_SYMBOL(set_irq_chip);
 149
 150 /**
 151  *      set_irq_type - set the irq trigger type for an irq
 152  *      @irq:   irq number
 153  *      @type:  IRQ_TYPE_{LEVEL,EDGE}_* value - see include/linux/irq.h
 154  */
 155 int set_irq_type(unsigned int irq, unsigned int type)
 156 {
 157         struct irq_desc *desc = irq_to_desc(irq);
 158         unsigned long flags;
 159         int ret = -ENXIO;
 160
 161         if (!desc) {
 162                 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
 163                 return -ENODEV;
 164         }
 165
 166         type &= IRQ_TYPE_SENSE_MASK;
 167         if (type == IRQ_TYPE_NONE)
 168                 return 0;
 169
 170         raw_spin_lock_irqsave(&desc->lock, flags);
 171         ret = __irq_set_trigger(desc, irq, type);
 172         raw_spin_unlock_irqrestore(&desc->lock, flags);
 173         return ret;
 174 }
 175 EXPORT_SYMBOL(set_irq_type);
 176
 177 /**
 178  *      set_irq_data - set irq type data for an irq
 179  *      @irq:   Interrupt number
 180  *      @data:  Pointer to interrupt specific data
 181  *
 182  *      Set the hardware irq controller data for an irq
 183  */
 184 int set_irq_data(unsigned int irq, void *data)
 185 {
 186         struct irq_desc *desc = irq_to_desc(irq);
 187         unsigned long flags;
 188
 189         if (!desc) {
 190                 printk(KERN_ERR
 191                        "Trying to install controller data for IRQ%d\n", irq);
 192                 return -EINVAL;
 193         }
 194
 195         raw_spin_lock_irqsave(&desc->lock, flags);
 196         desc->handler_data = data;
 197         raw_spin_unlock_irqrestore(&desc->lock, flags);
 198         return 0;
 199 }
 200 EXPORT_SYMBOL(set_irq_data);
 201
 202 /**
 203  *      set_irq_msi - set MSI descriptor data for an irq
 204  *      @irq:   Interrupt number
 205  *      @entry: Pointer to MSI descriptor data
 206  *
 207  *      Set the MSI descriptor entry for an irq
 208  */
 209 int set_irq_msi(unsigned int irq, struct msi_desc *entry)
 210 {
 211         struct irq_desc *desc = irq_to_desc(irq);
 212         unsigned long flags;
 213
 214         if (!desc) {
 215                 printk(KERN_ERR
 216                        "Trying to install msi data for IRQ%d\n", irq);
 217                 return -EINVAL;
 218         }
 219
 220         raw_spin_lock_irqsave(&desc->lock, flags);
 221         desc->msi_desc = entry;
 222         if (entry)
 223                 entry->irq = irq;
 224         raw_spin_unlock_irqrestore(&desc->lock, flags);
 225         return 0;
 226 }
 227
 228 /**
 229  *      set_irq_chip_data - set irq chip data for an irq
 230  *      @irq:   Interrupt number
 231  *      @data:  Pointer to chip specific data
 232  *
 233  *      Set the hardware irq chip data for an irq
 234  */
 235 int set_irq_chip_data(unsigned int irq, void *data)
 236 {
 237         struct irq_desc *desc = irq_to_desc(irq);
 238         unsigned long flags;
 239
 240         if (!desc) {
 241                 printk(KERN_ERR
 242                        "Trying to install chip data for IRQ%d\n", irq);
 243                 return -EINVAL;
 244         }
 245
 246         if (!desc->chip) {
 247                 printk(KERN_ERR "BUG: bad set_irq_chip_data(IRQ#%d)\n", irq);
 248                 return -EINVAL;
 249         }
 250
 251         raw_spin_lock_irqsave(&desc->lock, flags);
 252         desc->chip_data = data;
 253         raw_spin_unlock_irqrestore(&desc->lock, flags);
 254
 255         return 0;
 256 }
 257 EXPORT_SYMBOL(set_irq_chip_data);
 258
 259 /**
 260  *      set_irq_nested_thread - Set/Reset the IRQ_NESTED_THREAD flag of an irq
 261  *
 262  *      @irq:   Interrupt number
 263  *      @nest:  0 to clear / 1 to set the IRQ_NESTED_THREAD flag
 264  *
 265  *      The IRQ_NESTED_THREAD flag indicates that on
 266  *      request_threaded_irq() no separate interrupt thread should be
 267  *      created for the irq as the handler are called nested in the
 268  *      context of a demultiplexing interrupt handler thread.
 269  */
 270 void set_irq_nested_thread(unsigned int irq, int nest)
 271 {
 272         struct irq_desc *desc = irq_to_desc(irq);
 273         unsigned long flags;
 274
 275         if (!desc)
 276                 return;
 277
 278         raw_spin_lock_irqsave(&desc->lock, flags);
 279         if (nest)
 280                 desc->status |= IRQ_NESTED_THREAD;
 281         else
 282                 desc->status &= ~IRQ_NESTED_THREAD;
 283         raw_spin_unlock_irqrestore(&desc->lock, flags);
 284 }
 285 EXPORT_SYMBOL_GPL(set_irq_nested_thread);
 286
 287 /*
 288  * default enable function
 289  */
 290 static void default_enable(unsigned int irq)
 291 {
 292         struct irq_desc *desc = irq_to_desc(irq);
 293
 294         desc->chip->unmask(irq);
 295         desc->status &= ~IRQ_MASKED;
 296 }
 297
 298 /*
 299  * default disable function
 300  */
 301 static void default_disable(unsigned int irq)
 302 {
 303 }
 304
 305 /*
 306  * default startup function
 307  */
 308 static unsigned int default_startup(unsigned int irq)
 309 {
 310         struct irq_desc *desc = irq_to_desc(irq);
 311
 312         desc->chip->enable(irq);
 313         return 0;
 314 }
 315
 316 /*
 317  * default shutdown function
 318  */
 319 static void default_shutdown(unsigned int irq)
 320 {
 321         struct irq_desc *desc = irq_to_desc(irq);
 322
 323         desc->chip->mask(irq);
 324         desc->status |= IRQ_MASKED;
 325 }
 326
 327 /*
 328  * Fixup enable/disable function pointers
 329  */
 330 void irq_chip_set_defaults(struct irq_chip *chip)
 331 {
 332         if (!chip->enable)
 333                 chip->enable = default_enable;
 334         if (!chip->disable)
 335                 chip->disable = default_disable;
 336         if (!chip->startup)
 337                 chip->startup = default_startup;
 338         /*
 339          * We use chip->disable, when the user provided its own. When
 340          * we have default_disable set for chip->disable, then we need
 341          * to use default_shutdown, otherwise the irq line is not
 342          * disabled on free_irq():
 343          */
 344         if (!chip->shutdown)
 345                 chip->shutdown = chip->disable != default_disable ?
 346                         chip->disable : default_shutdown;
 347         if (!chip->name)
 348                 chip->name = chip->typename;
 349         if (!chip->end)
 350                 chip->end = dummy_irq_chip.end;
 351 }
 352
 353 static inline void mask_ack_irq(struct irq_desc *desc, int irq)
 354 {
 355         if (desc->chip->mask_ack)
 356                 desc->chip->mask_ack(irq);
 357         else {
 358                 desc->chip->mask(irq);
 359                 if (desc->chip->ack)
 360                         desc->chip->ack(irq);
 361         }
 362         desc->status |= IRQ_MASKED;
 363 }
 364
 365 static inline void mask_irq(struct irq_desc *desc, int irq)
 366 {
 367         if (desc->chip->mask) {
 368                 desc->chip->mask(irq);
 369                 desc->status |= IRQ_MASKED;
 370         }
 371 }
 372
 373 static inline void unmask_irq(struct irq_desc *desc, int irq)
 374 {
 375         if (desc->chip->unmask) {
 376                 desc->chip->unmask(irq);
 377                 desc->status &= ~IRQ_MASKED;
 378         }
 379 }
 380
 381 /*
 382  *      handle_nested_irq - Handle a nested irq from a irq thread
 383  *      @irq:   the interrupt number
 384  *
 385  *      Handle interrupts which are nested into a threaded interrupt
 386  *      handler. The handler function is called inside the calling
 387  *      threads context.
 388  */
 389 void handle_nested_irq(unsigned int irq)
 390 {
 391         struct irq_desc *desc = irq_to_desc(irq);
 392         struct irqaction *action;
 393         irqreturn_t action_ret;
 394
 395         might_sleep();
 396
 397         raw_spin_lock_irq(&desc->lock);
 398
 399         kstat_incr_irqs_this_cpu(irq, desc);
 400
 401         action = desc->action;
 402         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 403                 goto out_unlock;
 404
 405         desc->status |= IRQ_INPROGRESS;
 406         raw_spin_unlock_irq(&desc->lock);
 407
 408         action_ret = action->thread_fn(action->irq, action->dev_id);
 409         if (!noirqdebug)
 410                 note_interrupt(irq, desc, action_ret);
 411
 412         raw_spin_lock_irq(&desc->lock);
 413         desc->status &= ~IRQ_INPROGRESS;
 414
 415 out_unlock:
 416         raw_spin_unlock_irq(&desc->lock);
 417 }
 418 EXPORT_SYMBOL_GPL(handle_nested_irq);
 419
 420 /**
 421  *      handle_simple_irq - Simple and software-decoded IRQs.
 422  *      @irq:   the interrupt number
 423  *      @desc:  the interrupt description structure for this irq
 424  *
 425  *      Simple interrupts are either sent from a demultiplexing interrupt
 426  *      handler or come from hardware, where no interrupt hardware control
 427  *      is necessary.
 428  *
 429  *      Note: The caller is expected to handle the ack, clear, mask and
 430  *      unmask issues if necessary.
 431  */
 432 void
 433 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
 434 {
 435         struct irqaction *action;
 436         irqreturn_t action_ret;
 437
 438         raw_spin_lock(&desc->lock);
 439
 440         if (unlikely(desc->status & IRQ_INPROGRESS))
 441                 goto out_unlock;
 442         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 443         kstat_incr_irqs_this_cpu(irq, desc);
 444
 445         action = desc->action;
 446         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 447                 goto out_unlock;
 448
 449         desc->status |= IRQ_INPROGRESS;
 450         raw_spin_unlock(&desc->lock);
 451
 452         action_ret = handle_IRQ_event(irq, action);
 453         if (!noirqdebug)
 454                 note_interrupt(irq, desc, action_ret);
 455
 456         raw_spin_lock(&desc->lock);
 457         desc->status &= ~IRQ_INPROGRESS;
 458 out_unlock:
 459         raw_spin_unlock(&desc->lock);
 460 }
 461
 462 /**
 463  *      handle_level_irq - Level type irq handler
 464  *      @irq:   the interrupt number
 465  *      @desc:  the interrupt description structure for this irq
 466  *
 467  *      Level type interrupts are active as long as the hardware line has
 468  *      the active level. This may require to mask the interrupt and unmask
 469  *      it after the associated handler has acknowledged the device, so the
 470  *      interrupt line is back to inactive.
 471  */
 472 void
 473 handle_level_irq(unsigned int irq, struct irq_desc *desc)
 474 {
 475         struct irqaction *action;
 476         irqreturn_t action_ret;
 477
 478         raw_spin_lock(&desc->lock);
 479         mask_ack_irq(desc, irq);
 480
 481         if (unlikely(desc->status & IRQ_INPROGRESS))
 482                 goto out_unlock;
 483         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 484         kstat_incr_irqs_this_cpu(irq, desc);
 485
 486         /*
 487          * If its disabled or no action available
 488          * keep it masked and get out of here
 489          */
 490         action = desc->action;
 491         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 492                 goto out_unlock;
 493
 494         desc->status |= IRQ_INPROGRESS;
 495         raw_spin_unlock(&desc->lock);
 496
 497         action_ret = handle_IRQ_event(irq, action);
 498         if (!noirqdebug)
 499                 note_interrupt(irq, desc, action_ret);
 500
 501         raw_spin_lock(&desc->lock);
 502         desc->status &= ~IRQ_INPROGRESS;
 503
 504         if (!(desc->status & (IRQ_DISABLED | IRQ_ONESHOT)))
 505                 unmask_irq(desc, irq);
 506 out_unlock:
 507         raw_spin_unlock(&desc->lock);
 508 }
 509 EXPORT_SYMBOL_GPL(handle_level_irq);
 510
 511 /**
 512  *      handle_fasteoi_irq - irq handler for transparent controllers
 513  *      @irq:   the interrupt number
 514  *      @desc:  the interrupt description structure for this irq
 515  *
 516  *      Only a single callback will be issued to the chip: an ->eoi()
 517  *      call when the interrupt has been serviced. This enables support
 518  *      for modern forms of interrupt handlers, which handle the flow
 519  *      details in hardware, transparently.
 520  */
 521 void
 522 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 523 {
 524         struct irqaction *action;
 525         irqreturn_t action_ret;
 526
 527         raw_spin_lock(&desc->lock);
 528
 529         if (unlikely(desc->status & IRQ_INPROGRESS))
 530                 goto out;
 531
 532         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 533         kstat_incr_irqs_this_cpu(irq, desc);
 534
 535         /*
 536          * If its disabled or no action available
 537          * then mask it and get out of here:
 538          */
 539         action = desc->action;
 540         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 541                 desc->status |= IRQ_PENDING;
 542                 mask_irq(desc, irq);
 543                 goto out;
 544         }
 545
 546         desc->status |= IRQ_INPROGRESS;
 547         desc->status &= ~IRQ_PENDING;
 548         raw_spin_unlock(&desc->lock);
 549
 550         action_ret = handle_IRQ_event(irq, action);
 551         if (!noirqdebug)
 552                 note_interrupt(irq, desc, action_ret);
 553
 554         raw_spin_lock(&desc->lock);
 555         desc->status &= ~IRQ_INPROGRESS;
 556 out:
 557         desc->chip->eoi(irq);
 558
 559         raw_spin_unlock(&desc->lock);
 560 }
 561
 562 /**
 563  *      handle_edge_irq - edge type IRQ handler
 564  *      @irq:   the interrupt number
 565  *      @desc:  the interrupt description structure for this irq
 566  *
 567  *      Interrupt occures on the falling and/or rising edge of a hardware
 568  *      signal. The occurence is latched into the irq controller hardware
 569  *      and must be acked in order to be reenabled. After the ack another
 570  *      interrupt can happen on the same source even before the first one
 571  *      is handled by the associated event handler. If this happens it
 572  *      might be necessary to disable (mask) the interrupt depending on the
 573  *      controller hardware. This requires to reenable the interrupt inside
 574  *      of the loop which handles the interrupts which have arrived while
 575  *      the handler was running. If all pending interrupts are handled, the
 576  *      loop is left.
 577  */
 578 void
 579 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
 580 {
 581         raw_spin_lock(&desc->lock);
 582
 583         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 584
 585         /*
 586          * If we're currently running this IRQ, or its disabled,
 587          * we shouldn't process the IRQ. Mark it pending, handle
 588          * the necessary masking and go out
 589          */
 590         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 591                     !desc->action)) {
 592                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 593                 mask_ack_irq(desc, irq);
 594                 goto out_unlock;
 595         }
 596         kstat_incr_irqs_this_cpu(irq, desc);
 597
 598         /* Start handling the irq */
 599         if (desc->chip->ack)
 600                 desc->chip->ack(irq);
 601
 602         /* Mark the IRQ currently in progress.*/
 603         desc->status |= IRQ_INPROGRESS;
 604
 605         do {
 606                 struct irqaction *action = desc->action;
 607                 irqreturn_t action_ret;
 608
 609                 if (unlikely(!action)) {
 610                         mask_irq(desc, irq);
 611                         goto out_unlock;
 612                 }
 613
 614                 /*
 615                  * When another irq arrived while we were handling
 616                  * one, we could have masked the irq.
 617                  * Renable it, if it was not disabled in meantime.
 618                  */
 619                 if (unlikely((desc->status &
 620                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 621                               (IRQ_PENDING | IRQ_MASKED))) {
 622                         unmask_irq(desc, irq);
 623                 }
 624
 625                 desc->status &= ~IRQ_PENDING;
 626                 raw_spin_unlock(&desc->lock);
 627                 action_ret = handle_IRQ_event(irq, action);
 628                 if (!noirqdebug)
 629                         note_interrupt(irq, desc, action_ret);
 630                 raw_spin_lock(&desc->lock);
 631
 632         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 633
 634         desc->status &= ~IRQ_INPROGRESS;
 635 out_unlock:
 636         raw_spin_unlock(&desc->lock);
 637 }
 638
 639 /**
 640  *      handle_percpu_irq - Per CPU local irq handler
 641  *      @irq:   the interrupt number
 642  *      @desc:  the interrupt description structure for this irq
 643  *
 644  *      Per CPU interrupts on SMP machines without locking requirements
 645  */
 646 void
 647 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
 648 {
 649         irqreturn_t action_ret;
 650
 651         kstat_incr_irqs_this_cpu(irq, desc);
 652
 653         if (desc->chip->ack)
 654                 desc->chip->ack(irq);
 655
 656         action_ret = handle_IRQ_event(irq, desc->action);
 657         if (!noirqdebug)
 658                 note_interrupt(irq, desc, action_ret);
 659
 660         if (desc->chip->eoi)
 661                 desc->chip->eoi(irq);
 662 }
 663
 664 void
 665 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
 666                   const char *name)
 667 {
 668         struct irq_desc *desc = irq_to_desc(irq);
 669         unsigned long flags;
 670
 671         if (!desc) {
 672                 printk(KERN_ERR
 673                        "Trying to install type control for IRQ%d\n", irq);
 674                 return;
 675         }
 676
 677         if (!handle)
 678                 handle = handle_bad_irq;
 679         else if (desc->chip == &no_irq_chip) {
 680                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 681                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
 682                 /*
 683                  * Some ARM implementations install a handler for really dumb
 684                  * interrupt hardware without setting an irq_chip. This worked
 685                  * with the ARM no_irq_chip but the check in setup_irq would
 686                  * prevent us to setup the interrupt at all. Switch it to
 687                  * dummy_irq_chip for easy transition.
 688                  */
 689                 desc->chip = &dummy_irq_chip;
 690         }
 691
 692         chip_bus_lock(irq, desc);
 693         raw_spin_lock_irqsave(&desc->lock, flags);
 694
 695         /* Uninstall? */
 696         if (handle == handle_bad_irq) {
 697                 if (desc->chip != &no_irq_chip)
 698                         mask_ack_irq(desc, irq);
 699                 desc->status |= IRQ_DISABLED;
 700                 desc->depth = 1;
 701         }
 702         desc->handle_irq = handle;
 703         desc->name = name;
 704
 705         if (handle != handle_bad_irq && is_chained) {
 706                 desc->status &= ~IRQ_DISABLED;
 707                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 708                 desc->depth = 0;
 709                 desc->chip->startup(irq);
 710         }
 711         raw_spin_unlock_irqrestore(&desc->lock, flags);
 712         chip_bus_sync_unlock(irq, desc);
 713 }
 714 EXPORT_SYMBOL_GPL(__set_irq_handler);
 715
 716 void
 717 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 718                          irq_flow_handler_t handle)
 719 {
 720         set_irq_chip(irq, chip);
 721         __set_irq_handler(irq, handle, 0, NULL);
 722 }
 723
 724 void
 725 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
 726                               irq_flow_handler_t handle, const char *name)
 727 {
 728         set_irq_chip(irq, chip);
 729         __set_irq_handler(irq, handle, 0, name);
 730 }
 731
 732 void set_irq_noprobe(unsigned int irq)
 733 {
 734         struct irq_desc *desc = irq_to_desc(irq);
 735         unsigned long flags;
 736
 737         if (!desc) {
 738                 printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);
 739                 return;
 740         }
 741
 742         raw_spin_lock_irqsave(&desc->lock, flags);
 743         desc->status |= IRQ_NOPROBE;
 744         raw_spin_unlock_irqrestore(&desc->lock, flags);
 745 }
 746
 747 void set_irq_probe(unsigned int irq)
 748 {
 749         struct irq_desc *desc = irq_to_desc(irq);
 750         unsigned long flags;
 751
 752         if (!desc) {
 753                 printk(KERN_ERR "Trying to mark IRQ%d probeable\n", irq);
 754                 return;
 755         }
 756
 757         raw_spin_lock_irqsave(&desc->lock, flags);
 758         desc->status &= ~IRQ_NOPROBE;
 759         raw_spin_unlock_irqrestore(&desc->lock, flags);
 760 }