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