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->end)
 348                 chip->end = dummy_irq_chip.end;
 349 }
 350
 351 static inline void mask_ack_irq(struct irq_desc *desc, int irq)
 352 {
 353         if (desc->chip->mask_ack)
 354                 desc->chip->mask_ack(irq);
 355         else {
 356                 desc->chip->mask(irq);
 357                 if (desc->chip->ack)
 358                         desc->chip->ack(irq);
 359         }
 360         desc->status |= IRQ_MASKED;
 361 }
 362
 363 static inline void mask_irq(struct irq_desc *desc, int irq)
 364 {
 365         if (desc->chip->mask) {
 366                 desc->chip->mask(irq);
 367                 desc->status |= IRQ_MASKED;
 368         }
 369 }
 370
 371 static inline void unmask_irq(struct irq_desc *desc, int irq)
 372 {
 373         if (desc->chip->unmask) {
 374                 desc->chip->unmask(irq);
 375                 desc->status &= ~IRQ_MASKED;
 376         }
 377 }
 378
 379 /*
 380  *      handle_nested_irq - Handle a nested irq from a irq thread
 381  *      @irq:   the interrupt number
 382  *
 383  *      Handle interrupts which are nested into a threaded interrupt
 384  *      handler. The handler function is called inside the calling
 385  *      threads context.
 386  */
 387 void handle_nested_irq(unsigned int irq)
 388 {
 389         struct irq_desc *desc = irq_to_desc(irq);
 390         struct irqaction *action;
 391         irqreturn_t action_ret;
 392
 393         might_sleep();
 394
 395         raw_spin_lock_irq(&desc->lock);
 396
 397         kstat_incr_irqs_this_cpu(irq, desc);
 398
 399         action = desc->action;
 400         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 401                 goto out_unlock;
 402
 403         desc->status |= IRQ_INPROGRESS;
 404         raw_spin_unlock_irq(&desc->lock);
 405
 406         action_ret = action->thread_fn(action->irq, action->dev_id);
 407         if (!noirqdebug)
 408                 note_interrupt(irq, desc, action_ret);
 409
 410         raw_spin_lock_irq(&desc->lock);
 411         desc->status &= ~IRQ_INPROGRESS;
 412
 413 out_unlock:
 414         raw_spin_unlock_irq(&desc->lock);
 415 }
 416 EXPORT_SYMBOL_GPL(handle_nested_irq);
 417
 418 /**
 419  *      handle_simple_irq - Simple and software-decoded IRQs.
 420  *      @irq:   the interrupt number
 421  *      @desc:  the interrupt description structure for this irq
 422  *
 423  *      Simple interrupts are either sent from a demultiplexing interrupt
 424  *      handler or come from hardware, where no interrupt hardware control
 425  *      is necessary.
 426  *
 427  *      Note: The caller is expected to handle the ack, clear, mask and
 428  *      unmask issues if necessary.
 429  */
 430 void
 431 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
 432 {
 433         struct irqaction *action;
 434         irqreturn_t action_ret;
 435
 436         raw_spin_lock(&desc->lock);
 437
 438         if (unlikely(desc->status & IRQ_INPROGRESS))
 439                 goto out_unlock;
 440         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 441         kstat_incr_irqs_this_cpu(irq, desc);
 442
 443         action = desc->action;
 444         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 445                 goto out_unlock;
 446
 447         desc->status |= IRQ_INPROGRESS;
 448         raw_spin_unlock(&desc->lock);
 449
 450         action_ret = handle_IRQ_event(irq, action);
 451         if (!noirqdebug)
 452                 note_interrupt(irq, desc, action_ret);
 453
 454         raw_spin_lock(&desc->lock);
 455         desc->status &= ~IRQ_INPROGRESS;
 456 out_unlock:
 457         raw_spin_unlock(&desc->lock);
 458 }
 459
 460 /**
 461  *      handle_level_irq - Level type irq handler
 462  *      @irq:   the interrupt number
 463  *      @desc:  the interrupt description structure for this irq
 464  *
 465  *      Level type interrupts are active as long as the hardware line has
 466  *      the active level. This may require to mask the interrupt and unmask
 467  *      it after the associated handler has acknowledged the device, so the
 468  *      interrupt line is back to inactive.
 469  */
 470 void
 471 handle_level_irq(unsigned int irq, struct irq_desc *desc)
 472 {
 473         struct irqaction *action;
 474         irqreturn_t action_ret;
 475
 476         raw_spin_lock(&desc->lock);
 477         mask_ack_irq(desc, irq);
 478
 479         if (unlikely(desc->status & IRQ_INPROGRESS))
 480                 goto out_unlock;
 481         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 482         kstat_incr_irqs_this_cpu(irq, desc);
 483
 484         /*
 485          * If its disabled or no action available
 486          * keep it masked and get out of here
 487          */
 488         action = desc->action;
 489         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 490                 goto out_unlock;
 491
 492         desc->status |= IRQ_INPROGRESS;
 493         raw_spin_unlock(&desc->lock);
 494
 495         action_ret = handle_IRQ_event(irq, action);
 496         if (!noirqdebug)
 497                 note_interrupt(irq, desc, action_ret);
 498
 499         raw_spin_lock(&desc->lock);
 500         desc->status &= ~IRQ_INPROGRESS;
 501
 502         if (!(desc->status & (IRQ_DISABLED | IRQ_ONESHOT)))
 503                 unmask_irq(desc, irq);
 504 out_unlock:
 505         raw_spin_unlock(&desc->lock);
 506 }
 507 EXPORT_SYMBOL_GPL(handle_level_irq);
 508
 509 /**
 510  *      handle_fasteoi_irq - irq handler for transparent controllers
 511  *      @irq:   the interrupt number
 512  *      @desc:  the interrupt description structure for this irq
 513  *
 514  *      Only a single callback will be issued to the chip: an ->eoi()
 515  *      call when the interrupt has been serviced. This enables support
 516  *      for modern forms of interrupt handlers, which handle the flow
 517  *      details in hardware, transparently.
 518  */
 519 void
 520 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 521 {
 522         struct irqaction *action;
 523         irqreturn_t action_ret;
 524
 525         raw_spin_lock(&desc->lock);
 526
 527         if (unlikely(desc->status & IRQ_INPROGRESS))
 528                 goto out;
 529
 530         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 531         kstat_incr_irqs_this_cpu(irq, desc);
 532
 533         /*
 534          * If its disabled or no action available
 535          * then mask it and get out of here:
 536          */
 537         action = desc->action;
 538         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 539                 desc->status |= IRQ_PENDING;
 540                 mask_irq(desc, irq);
 541                 goto out;
 542         }
 543
 544         desc->status |= IRQ_INPROGRESS;
 545         desc->status &= ~IRQ_PENDING;
 546         raw_spin_unlock(&desc->lock);
 547
 548         action_ret = handle_IRQ_event(irq, action);
 549         if (!noirqdebug)
 550                 note_interrupt(irq, desc, action_ret);
 551
 552         raw_spin_lock(&desc->lock);
 553         desc->status &= ~IRQ_INPROGRESS;
 554 out:
 555         desc->chip->eoi(irq);
 556
 557         raw_spin_unlock(&desc->lock);
 558 }
 559
 560 /**
 561  *      handle_edge_irq - edge type IRQ handler
 562  *      @irq:   the interrupt number
 563  *      @desc:  the interrupt description structure for this irq
 564  *
 565  *      Interrupt occures on the falling and/or rising edge of a hardware
 566  *      signal. The occurence is latched into the irq controller hardware
 567  *      and must be acked in order to be reenabled. After the ack another
 568  *      interrupt can happen on the same source even before the first one
 569  *      is handled by the associated event handler. If this happens it
 570  *      might be necessary to disable (mask) the interrupt depending on the
 571  *      controller hardware. This requires to reenable the interrupt inside
 572  *      of the loop which handles the interrupts which have arrived while
 573  *      the handler was running. If all pending interrupts are handled, the
 574  *      loop is left.
 575  */
 576 void
 577 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
 578 {
 579         raw_spin_lock(&desc->lock);
 580
 581         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 582
 583         /*
 584          * If we're currently running this IRQ, or its disabled,
 585          * we shouldn't process the IRQ. Mark it pending, handle
 586          * the necessary masking and go out
 587          */
 588         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 589                     !desc->action)) {
 590                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 591                 mask_ack_irq(desc, irq);
 592                 goto out_unlock;
 593         }
 594         kstat_incr_irqs_this_cpu(irq, desc);
 595
 596         /* Start handling the irq */
 597         if (desc->chip->ack)
 598                 desc->chip->ack(irq);
 599
 600         /* Mark the IRQ currently in progress.*/
 601         desc->status |= IRQ_INPROGRESS;
 602
 603         do {
 604                 struct irqaction *action = desc->action;
 605                 irqreturn_t action_ret;
 606
 607                 if (unlikely(!action)) {
 608                         mask_irq(desc, irq);
 609                         goto out_unlock;
 610                 }
 611
 612                 /*
 613                  * When another irq arrived while we were handling
 614                  * one, we could have masked the irq.
 615                  * Renable it, if it was not disabled in meantime.
 616                  */
 617                 if (unlikely((desc->status &
 618                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 619                               (IRQ_PENDING | IRQ_MASKED))) {
 620                         unmask_irq(desc, irq);
 621                 }
 622
 623                 desc->status &= ~IRQ_PENDING;
 624                 raw_spin_unlock(&desc->lock);
 625                 action_ret = handle_IRQ_event(irq, action);
 626                 if (!noirqdebug)
 627                         note_interrupt(irq, desc, action_ret);
 628                 raw_spin_lock(&desc->lock);
 629
 630         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 631
 632         desc->status &= ~IRQ_INPROGRESS;
 633 out_unlock:
 634         raw_spin_unlock(&desc->lock);
 635 }
 636
 637 /**
 638  *      handle_percpu_irq - Per CPU local irq handler
 639  *      @irq:   the interrupt number
 640  *      @desc:  the interrupt description structure for this irq
 641  *
 642  *      Per CPU interrupts on SMP machines without locking requirements
 643  */
 644 void
 645 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
 646 {
 647         irqreturn_t action_ret;
 648
 649         kstat_incr_irqs_this_cpu(irq, desc);
 650
 651         if (desc->chip->ack)
 652                 desc->chip->ack(irq);
 653
 654         action_ret = handle_IRQ_event(irq, desc->action);
 655         if (!noirqdebug)
 656                 note_interrupt(irq, desc, action_ret);
 657
 658         if (desc->chip->eoi)
 659                 desc->chip->eoi(irq);
 660 }
 661
 662 void
 663 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
 664                   const char *name)
 665 {
 666         struct irq_desc *desc = irq_to_desc(irq);
 667         unsigned long flags;
 668
 669         if (!desc) {
 670                 printk(KERN_ERR
 671                        "Trying to install type control for IRQ%d\n", irq);
 672                 return;
 673         }
 674
 675         if (!handle)
 676                 handle = handle_bad_irq;
 677         else if (desc->chip == &no_irq_chip) {
 678                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 679                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
 680                 /*
 681                  * Some ARM implementations install a handler for really dumb
 682                  * interrupt hardware without setting an irq_chip. This worked
 683                  * with the ARM no_irq_chip but the check in setup_irq would
 684                  * prevent us to setup the interrupt at all. Switch it to
 685                  * dummy_irq_chip for easy transition.
 686                  */
 687                 desc->chip = &dummy_irq_chip;
 688         }
 689
 690         chip_bus_lock(irq, desc);
 691         raw_spin_lock_irqsave(&desc->lock, flags);
 692
 693         /* Uninstall? */
 694         if (handle == handle_bad_irq) {
 695                 if (desc->chip != &no_irq_chip)
 696                         mask_ack_irq(desc, irq);
 697                 desc->status |= IRQ_DISABLED;
 698                 desc->depth = 1;
 699         }
 700         desc->handle_irq = handle;
 701         desc->name = name;
 702
 703         if (handle != handle_bad_irq && is_chained) {
 704                 desc->status &= ~IRQ_DISABLED;
 705                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 706                 desc->depth = 0;
 707                 desc->chip->startup(irq);
 708         }
 709         raw_spin_unlock_irqrestore(&desc->lock, flags);
 710         chip_bus_sync_unlock(irq, desc);
 711 }
 712 EXPORT_SYMBOL_GPL(__set_irq_handler);
 713
 714 void
 715 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 716                          irq_flow_handler_t handle)
 717 {
 718         set_irq_chip(irq, chip);
 719         __set_irq_handler(irq, handle, 0, NULL);
 720 }
 721
 722 void
 723 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
 724                               irq_flow_handler_t handle, const char *name)
 725 {
 726         set_irq_chip(irq, chip);
 727         __set_irq_handler(irq, handle, 0, name);
 728 }
 729
 730 void set_irq_noprobe(unsigned int irq)
 731 {
 732         struct irq_desc *desc = irq_to_desc(irq);
 733         unsigned long flags;
 734
 735         if (!desc) {
 736                 printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);
 737                 return;
 738         }
 739
 740         raw_spin_lock_irqsave(&desc->lock, flags);
 741         desc->status |= IRQ_NOPROBE;
 742         raw_spin_unlock_irqrestore(&desc->lock, flags);
 743 }
 744
 745 void set_irq_probe(unsigned int irq)
 746 {
 747         struct irq_desc *desc = irq_to_desc(irq);
 748         unsigned long flags;
 749
 750         if (!desc) {
 751                 printk(KERN_ERR "Trying to mark IRQ%d probeable\n", irq);
 752                 return;
 753         }
 754
 755         raw_spin_lock_irqsave(&desc->lock, flags);
 756         desc->status &= ~IRQ_NOPROBE;
 757         raw_spin_unlock_irqrestore(&desc->lock, flags);
 758 }