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