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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         clear_kstat_irqs(desc);
  82         spin_unlock_irqrestore(&desc->lock, flags);
  83 }
  84
  85
  86 /**
  87  *      set_irq_chip - set the irq chip for an irq
  88  *      @irq:   irq number
  89  *      @chip:  pointer to irq chip description structure
  90  */
  91 int set_irq_chip(unsigned int irq, struct irq_chip *chip)
  92 {
  93         struct irq_desc *desc = irq_to_desc(irq);
  94         unsigned long flags;
  95
  96         if (!desc) {
  97                 WARN(1, KERN_ERR "Trying to install chip for IRQ%d\n", irq);
  98                 return -EINVAL;
  99         }
 100
 101         if (!chip)
 102                 chip = &no_irq_chip;
 103
 104         spin_lock_irqsave(&desc->lock, flags);
 105         irq_chip_set_defaults(chip);
 106         desc->chip = chip;
 107         spin_unlock_irqrestore(&desc->lock, flags);
 108
 109         return 0;
 110 }
 111 EXPORT_SYMBOL(set_irq_chip);
 112
 113 /**
 114  *      set_irq_type - set the irq trigger type for an irq
 115  *      @irq:   irq number
 116  *      @type:  IRQ_TYPE_{LEVEL,EDGE}_* value - see include/linux/irq.h
 117  */
 118 int set_irq_type(unsigned int irq, unsigned int type)
 119 {
 120         struct irq_desc *desc = irq_to_desc(irq);
 121         unsigned long flags;
 122         int ret = -ENXIO;
 123
 124         if (!desc) {
 125                 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
 126                 return -ENODEV;
 127         }
 128
 129         type &= IRQ_TYPE_SENSE_MASK;
 130         if (type == IRQ_TYPE_NONE)
 131                 return 0;
 132
 133         spin_lock_irqsave(&desc->lock, flags);
 134         ret = __irq_set_trigger(desc, irq, type);
 135         spin_unlock_irqrestore(&desc->lock, flags);
 136         return ret;
 137 }
 138 EXPORT_SYMBOL(set_irq_type);
 139
 140 /**
 141  *      set_irq_data - set irq type data for an irq
 142  *      @irq:   Interrupt number
 143  *      @data:  Pointer to interrupt specific data
 144  *
 145  *      Set the hardware irq controller data for an irq
 146  */
 147 int set_irq_data(unsigned int irq, void *data)
 148 {
 149         struct irq_desc *desc = irq_to_desc(irq);
 150         unsigned long flags;
 151
 152         if (!desc) {
 153                 printk(KERN_ERR
 154                        "Trying to install controller data for IRQ%d\n", irq);
 155                 return -EINVAL;
 156         }
 157
 158         spin_lock_irqsave(&desc->lock, flags);
 159         desc->handler_data = data;
 160         spin_unlock_irqrestore(&desc->lock, flags);
 161         return 0;
 162 }
 163 EXPORT_SYMBOL(set_irq_data);
 164
 165 /**
 166  *      set_irq_data - set irq type data for an irq
 167  *      @irq:   Interrupt number
 168  *      @entry: Pointer to MSI descriptor data
 169  *
 170  *      Set the hardware irq controller data for an irq
 171  */
 172 int set_irq_msi(unsigned int irq, struct msi_desc *entry)
 173 {
 174         struct irq_desc *desc = irq_to_desc(irq);
 175         unsigned long flags;
 176
 177         if (!desc) {
 178                 printk(KERN_ERR
 179                        "Trying to install msi data for IRQ%d\n", irq);
 180                 return -EINVAL;
 181         }
 182
 183         spin_lock_irqsave(&desc->lock, flags);
 184         desc->msi_desc = entry;
 185         if (entry)
 186                 entry->irq = irq;
 187         spin_unlock_irqrestore(&desc->lock, flags);
 188         return 0;
 189 }
 190
 191 /**
 192  *      set_irq_chip_data - set irq chip data for an irq
 193  *      @irq:   Interrupt number
 194  *      @data:  Pointer to chip specific data
 195  *
 196  *      Set the hardware irq chip data for an irq
 197  */
 198 int set_irq_chip_data(unsigned int irq, void *data)
 199 {
 200         struct irq_desc *desc = irq_to_desc(irq);
 201         unsigned long flags;
 202
 203         if (!desc) {
 204                 printk(KERN_ERR
 205                        "Trying to install chip data for IRQ%d\n", irq);
 206                 return -EINVAL;
 207         }
 208
 209         if (!desc->chip) {
 210                 printk(KERN_ERR "BUG: bad set_irq_chip_data(IRQ#%d)\n", irq);
 211                 return -EINVAL;
 212         }
 213
 214         spin_lock_irqsave(&desc->lock, flags);
 215         desc->chip_data = data;
 216         spin_unlock_irqrestore(&desc->lock, flags);
 217
 218         return 0;
 219 }
 220 EXPORT_SYMBOL(set_irq_chip_data);
 221
 222 /*
 223  * default enable function
 224  */
 225 static void default_enable(unsigned int irq)
 226 {
 227         struct irq_desc *desc = irq_to_desc(irq);
 228
 229         desc->chip->unmask(irq);
 230         desc->status &= ~IRQ_MASKED;
 231 }
 232
 233 /*
 234  * default disable function
 235  */
 236 static void default_disable(unsigned int irq)
 237 {
 238 }
 239
 240 /*
 241  * default startup function
 242  */
 243 static unsigned int default_startup(unsigned int irq)
 244 {
 245         struct irq_desc *desc = irq_to_desc(irq);
 246
 247         desc->chip->enable(irq);
 248         return 0;
 249 }
 250
 251 /*
 252  * default shutdown function
 253  */
 254 static void default_shutdown(unsigned int irq)
 255 {
 256         struct irq_desc *desc = irq_to_desc(irq);
 257
 258         desc->chip->mask(irq);
 259         desc->status |= IRQ_MASKED;
 260 }
 261
 262 /*
 263  * Fixup enable/disable function pointers
 264  */
 265 void irq_chip_set_defaults(struct irq_chip *chip)
 266 {
 267         if (!chip->enable)
 268                 chip->enable = default_enable;
 269         if (!chip->disable)
 270                 chip->disable = default_disable;
 271         if (!chip->startup)
 272                 chip->startup = default_startup;
 273         /*
 274          * We use chip->disable, when the user provided its own. When
 275          * we have default_disable set for chip->disable, then we need
 276          * to use default_shutdown, otherwise the irq line is not
 277          * disabled on free_irq():
 278          */
 279         if (!chip->shutdown)
 280                 chip->shutdown = chip->disable != default_disable ?
 281                         chip->disable : default_shutdown;
 282         if (!chip->name)
 283                 chip->name = chip->typename;
 284         if (!chip->end)
 285                 chip->end = dummy_irq_chip.end;
 286 }
 287
 288 static inline void mask_ack_irq(struct irq_desc *desc, int irq)
 289 {
 290         if (desc->chip->mask_ack)
 291                 desc->chip->mask_ack(irq);
 292         else {
 293                 desc->chip->mask(irq);
 294                 if (desc->chip->ack)
 295                         desc->chip->ack(irq);
 296         }
 297 }
 298
 299 /**
 300  *      handle_simple_irq - Simple and software-decoded IRQs.
 301  *      @irq:   the interrupt number
 302  *      @desc:  the interrupt description structure for this irq
 303  *
 304  *      Simple interrupts are either sent from a demultiplexing interrupt
 305  *      handler or come from hardware, where no interrupt hardware control
 306  *      is necessary.
 307  *
 308  *      Note: The caller is expected to handle the ack, clear, mask and
 309  *      unmask issues if necessary.
 310  */
 311 void
 312 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
 313 {
 314         struct irqaction *action;
 315         irqreturn_t action_ret;
 316
 317         spin_lock(&desc->lock);
 318
 319         if (unlikely(desc->status & IRQ_INPROGRESS))
 320                 goto out_unlock;
 321         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 322         kstat_incr_irqs_this_cpu(irq, desc);
 323
 324         action = desc->action;
 325         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 326                 goto out_unlock;
 327
 328         desc->status |= IRQ_INPROGRESS;
 329         spin_unlock(&desc->lock);
 330
 331         action_ret = handle_IRQ_event(irq, action);
 332         if (!noirqdebug)
 333                 note_interrupt(irq, desc, action_ret);
 334
 335         spin_lock(&desc->lock);
 336         desc->status &= ~IRQ_INPROGRESS;
 337 out_unlock:
 338         spin_unlock(&desc->lock);
 339 }
 340
 341 /**
 342  *      handle_level_irq - Level type irq handler
 343  *      @irq:   the interrupt number
 344  *      @desc:  the interrupt description structure for this irq
 345  *
 346  *      Level type interrupts are active as long as the hardware line has
 347  *      the active level. This may require to mask the interrupt and unmask
 348  *      it after the associated handler has acknowledged the device, so the
 349  *      interrupt line is back to inactive.
 350  */
 351 void
 352 handle_level_irq(unsigned int irq, struct irq_desc *desc)
 353 {
 354         struct irqaction *action;
 355         irqreturn_t action_ret;
 356
 357         spin_lock(&desc->lock);
 358         mask_ack_irq(desc, irq);
 359         desc = irq_remap_to_desc(irq, desc);
 360
 361         if (unlikely(desc->status & IRQ_INPROGRESS))
 362                 goto out_unlock;
 363         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 364         kstat_incr_irqs_this_cpu(irq, desc);
 365
 366         /*
 367          * If its disabled or no action available
 368          * keep it masked and get out of here
 369          */
 370         action = desc->action;
 371         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 372                 goto out_unlock;
 373
 374         desc->status |= IRQ_INPROGRESS;
 375         spin_unlock(&desc->lock);
 376
 377         action_ret = handle_IRQ_event(irq, action);
 378         if (!noirqdebug)
 379                 note_interrupt(irq, desc, action_ret);
 380
 381         spin_lock(&desc->lock);
 382         desc->status &= ~IRQ_INPROGRESS;
 383         if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
 384                 desc->chip->unmask(irq);
 385 out_unlock:
 386         spin_unlock(&desc->lock);
 387 }
 388 EXPORT_SYMBOL_GPL(handle_level_irq);
 389
 390 /**
 391  *      handle_fasteoi_irq - irq handler for transparent controllers
 392  *      @irq:   the interrupt number
 393  *      @desc:  the interrupt description structure for this irq
 394  *
 395  *      Only a single callback will be issued to the chip: an ->eoi()
 396  *      call when the interrupt has been serviced. This enables support
 397  *      for modern forms of interrupt handlers, which handle the flow
 398  *      details in hardware, transparently.
 399  */
 400 void
 401 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 402 {
 403         struct irqaction *action;
 404         irqreturn_t action_ret;
 405
 406         spin_lock(&desc->lock);
 407
 408         if (unlikely(desc->status & IRQ_INPROGRESS))
 409                 goto out;
 410
 411         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 412         kstat_incr_irqs_this_cpu(irq, desc);
 413
 414         /*
 415          * If its disabled or no action available
 416          * then mask it and get out of here:
 417          */
 418         action = desc->action;
 419         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 420                 desc->status |= IRQ_PENDING;
 421                 if (desc->chip->mask)
 422                         desc->chip->mask(irq);
 423                 goto out;
 424         }
 425
 426         desc->status |= IRQ_INPROGRESS;
 427         desc->status &= ~IRQ_PENDING;
 428         spin_unlock(&desc->lock);
 429
 430         action_ret = handle_IRQ_event(irq, action);
 431         if (!noirqdebug)
 432                 note_interrupt(irq, desc, action_ret);
 433
 434         spin_lock(&desc->lock);
 435         desc->status &= ~IRQ_INPROGRESS;
 436 out:
 437         desc->chip->eoi(irq);
 438         desc = irq_remap_to_desc(irq, desc);
 439
 440         spin_unlock(&desc->lock);
 441 }
 442
 443 /**
 444  *      handle_edge_irq - edge type IRQ handler
 445  *      @irq:   the interrupt number
 446  *      @desc:  the interrupt description structure for this irq
 447  *
 448  *      Interrupt occures on the falling and/or rising edge of a hardware
 449  *      signal. The occurence is latched into the irq controller hardware
 450  *      and must be acked in order to be reenabled. After the ack another
 451  *      interrupt can happen on the same source even before the first one
 452  *      is handled by the assosiacted event handler. If this happens it
 453  *      might be necessary to disable (mask) the interrupt depending on the
 454  *      controller hardware. This requires to reenable the interrupt inside
 455  *      of the loop which handles the interrupts which have arrived while
 456  *      the handler was running. If all pending interrupts are handled, the
 457  *      loop is left.
 458  */
 459 void
 460 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
 461 {
 462         spin_lock(&desc->lock);
 463
 464         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 465
 466         /*
 467          * If we're currently running this IRQ, or its disabled,
 468          * we shouldn't process the IRQ. Mark it pending, handle
 469          * the necessary masking and go out
 470          */
 471         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 472                     !desc->action)) {
 473                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 474                 mask_ack_irq(desc, irq);
 475                 desc = irq_remap_to_desc(irq, desc);
 476                 goto out_unlock;
 477         }
 478         kstat_incr_irqs_this_cpu(irq, desc);
 479
 480         /* Start handling the irq */
 481         if (desc->chip->ack)
 482                 desc->chip->ack(irq);
 483         desc = irq_remap_to_desc(irq, desc);
 484
 485         /* Mark the IRQ currently in progress.*/
 486         desc->status |= IRQ_INPROGRESS;
 487
 488         do {
 489                 struct irqaction *action = desc->action;
 490                 irqreturn_t action_ret;
 491
 492                 if (unlikely(!action)) {
 493                         desc->chip->mask(irq);
 494                         goto out_unlock;
 495                 }
 496
 497                 /*
 498                  * When another irq arrived while we were handling
 499                  * one, we could have masked the irq.
 500                  * Renable it, if it was not disabled in meantime.
 501                  */
 502                 if (unlikely((desc->status &
 503                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 504                               (IRQ_PENDING | IRQ_MASKED))) {
 505                         desc->chip->unmask(irq);
 506                         desc->status &= ~IRQ_MASKED;
 507                 }
 508
 509                 desc->status &= ~IRQ_PENDING;
 510                 spin_unlock(&desc->lock);
 511                 action_ret = handle_IRQ_event(irq, action);
 512                 if (!noirqdebug)
 513                         note_interrupt(irq, desc, action_ret);
 514                 spin_lock(&desc->lock);
 515
 516         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 517
 518         desc->status &= ~IRQ_INPROGRESS;
 519 out_unlock:
 520         spin_unlock(&desc->lock);
 521 }
 522
 523 /**
 524  *      handle_percpu_IRQ - Per CPU local irq handler
 525  *      @irq:   the interrupt number
 526  *      @desc:  the interrupt description structure for this irq
 527  *
 528  *      Per CPU interrupts on SMP machines without locking requirements
 529  */
 530 void
 531 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
 532 {
 533         irqreturn_t action_ret;
 534
 535         kstat_incr_irqs_this_cpu(irq, desc);
 536
 537         if (desc->chip->ack)
 538                 desc->chip->ack(irq);
 539
 540         action_ret = handle_IRQ_event(irq, desc->action);
 541         if (!noirqdebug)
 542                 note_interrupt(irq, desc, action_ret);
 543
 544         if (desc->chip->eoi) {
 545                 desc->chip->eoi(irq);
 546                 desc = irq_remap_to_desc(irq, desc);
 547         }
 548 }
 549
 550 void
 551 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
 552                   const char *name)
 553 {
 554         struct irq_desc *desc = irq_to_desc(irq);
 555         unsigned long flags;
 556
 557         if (!desc) {
 558                 printk(KERN_ERR
 559                        "Trying to install type control for IRQ%d\n", irq);
 560                 return;
 561         }
 562
 563         if (!handle)
 564                 handle = handle_bad_irq;
 565         else if (desc->chip == &no_irq_chip) {
 566                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 567                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
 568                 /*
 569                  * Some ARM implementations install a handler for really dumb
 570                  * interrupt hardware without setting an irq_chip. This worked
 571                  * with the ARM no_irq_chip but the check in setup_irq would
 572                  * prevent us to setup the interrupt at all. Switch it to
 573                  * dummy_irq_chip for easy transition.
 574                  */
 575                 desc->chip = &dummy_irq_chip;
 576         }
 577
 578         spin_lock_irqsave(&desc->lock, flags);
 579
 580         /* Uninstall? */
 581         if (handle == handle_bad_irq) {
 582                 if (desc->chip != &no_irq_chip) {
 583                         mask_ack_irq(desc, irq);
 584                         desc = irq_remap_to_desc(irq, desc);
 585                 }
 586                 desc->status |= IRQ_DISABLED;
 587                 desc->depth = 1;
 588         }
 589         desc->handle_irq = handle;
 590         desc->name = name;
 591
 592         if (handle != handle_bad_irq && is_chained) {
 593                 desc->status &= ~IRQ_DISABLED;
 594                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 595                 desc->depth = 0;
 596                 desc->chip->startup(irq);
 597         }
 598         spin_unlock_irqrestore(&desc->lock, flags);
 599 }
 600 EXPORT_SYMBOL_GPL(__set_irq_handler);
 601
 602 void
 603 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 604                          irq_flow_handler_t handle)
 605 {
 606         set_irq_chip(irq, chip);
 607         __set_irq_handler(irq, handle, 0, NULL);
 608 }
 609
 610 void
 611 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
 612                               irq_flow_handler_t handle, const char *name)
 613 {
 614         set_irq_chip(irq, chip);
 615         __set_irq_handler(irq, handle, 0, name);
 616 }
 617
 618 void __init set_irq_noprobe(unsigned int irq)
 619 {
 620         struct irq_desc *desc = irq_to_desc(irq);
 621         unsigned long flags;
 622
 623         if (!desc) {
 624                 printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);
 625                 return;
 626         }
 627
 628         spin_lock_irqsave(&desc->lock, flags);
 629         desc->status |= IRQ_NOPROBE;
 630         spin_unlock_irqrestore(&desc->lock, flags);
 631 }
 632
 633 void __init set_irq_probe(unsigned int irq)
 634 {
 635         struct irq_desc *desc = irq_to_desc(irq);
 636         unsigned long flags;
 637
 638         if (!desc) {
 639                 printk(KERN_ERR "Trying to mark IRQ%d probeable\n", irq);
 640                 return;
 641         }
 642
 643         spin_lock_irqsave(&desc->lock, flags);
 644         desc->status &= ~IRQ_NOPROBE;
 645         spin_unlock_irqrestore(&desc->lock, flags);
 646 }