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