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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                 if (desc->chip->ack)
 294                         desc->chip->ack(irq);
 295         }
 296 }
 297
 298 /**
 299  *      handle_simple_irq - Simple and software-decoded IRQs.
 300  *      @irq:   the interrupt number
 301  *      @desc:  the interrupt description structure for this irq
 302  *
 303  *      Simple interrupts are either sent from a demultiplexing interrupt
 304  *      handler or come from hardware, where no interrupt hardware control
 305  *      is necessary.
 306  *
 307  *      Note: The caller is expected to handle the ack, clear, mask and
 308  *      unmask issues if necessary.
 309  */
 310 void
 311 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
 312 {
 313         struct irqaction *action;
 314         irqreturn_t action_ret;
 315
 316         spin_lock(&desc->lock);
 317
 318         if (unlikely(desc->status & IRQ_INPROGRESS))
 319                 goto out_unlock;
 320         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 321         kstat_incr_irqs_this_cpu(irq, desc);
 322
 323         action = desc->action;
 324         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 325                 goto out_unlock;
 326
 327         desc->status |= IRQ_INPROGRESS;
 328         spin_unlock(&desc->lock);
 329
 330         action_ret = handle_IRQ_event(irq, action);
 331         if (!noirqdebug)
 332                 note_interrupt(irq, desc, action_ret);
 333
 334         spin_lock(&desc->lock);
 335         desc->status &= ~IRQ_INPROGRESS;
 336 out_unlock:
 337         spin_unlock(&desc->lock);
 338 }
 339
 340 /**
 341  *      handle_level_irq - Level type irq handler
 342  *      @irq:   the interrupt number
 343  *      @desc:  the interrupt description structure for this irq
 344  *
 345  *      Level type interrupts are active as long as the hardware line has
 346  *      the active level. This may require to mask the interrupt and unmask
 347  *      it after the associated handler has acknowledged the device, so the
 348  *      interrupt line is back to inactive.
 349  */
 350 void
 351 handle_level_irq(unsigned int irq, struct irq_desc *desc)
 352 {
 353         struct irqaction *action;
 354         irqreturn_t action_ret;
 355
 356         spin_lock(&desc->lock);
 357         mask_ack_irq(desc, irq);
 358         desc = irq_remap_to_desc(irq, desc);
 359
 360         if (unlikely(desc->status & IRQ_INPROGRESS))
 361                 goto out_unlock;
 362         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 363         kstat_incr_irqs_this_cpu(irq, desc);
 364
 365         /*
 366          * If its disabled or no action available
 367          * keep it masked and get out of here
 368          */
 369         action = desc->action;
 370         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 371                 goto out_unlock;
 372
 373         desc->status |= IRQ_INPROGRESS;
 374         spin_unlock(&desc->lock);
 375
 376         action_ret = handle_IRQ_event(irq, action);
 377         if (!noirqdebug)
 378                 note_interrupt(irq, desc, action_ret);
 379
 380         spin_lock(&desc->lock);
 381         desc->status &= ~IRQ_INPROGRESS;
 382         if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
 383                 desc->chip->unmask(irq);
 384 out_unlock:
 385         spin_unlock(&desc->lock);
 386 }
 387 EXPORT_SYMBOL_GPL(handle_level_irq);
 388
 389 /**
 390  *      handle_fasteoi_irq - irq handler for transparent controllers
 391  *      @irq:   the interrupt number
 392  *      @desc:  the interrupt description structure for this irq
 393  *
 394  *      Only a single callback will be issued to the chip: an ->eoi()
 395  *      call when the interrupt has been serviced. This enables support
 396  *      for modern forms of interrupt handlers, which handle the flow
 397  *      details in hardware, transparently.
 398  */
 399 void
 400 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 401 {
 402         struct irqaction *action;
 403         irqreturn_t action_ret;
 404
 405         spin_lock(&desc->lock);
 406
 407         if (unlikely(desc->status & IRQ_INPROGRESS))
 408                 goto out;
 409
 410         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 411         kstat_incr_irqs_this_cpu(irq, desc);
 412
 413         /*
 414          * If its disabled or no action available
 415          * then mask it and get out of here:
 416          */
 417         action = desc->action;
 418         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 419                 desc->status |= IRQ_PENDING;
 420                 if (desc->chip->mask)
 421                         desc->chip->mask(irq);
 422                 goto out;
 423         }
 424
 425         desc->status |= IRQ_INPROGRESS;
 426         desc->status &= ~IRQ_PENDING;
 427         spin_unlock(&desc->lock);
 428
 429         action_ret = handle_IRQ_event(irq, action);
 430         if (!noirqdebug)
 431                 note_interrupt(irq, desc, action_ret);
 432
 433         spin_lock(&desc->lock);
 434         desc->status &= ~IRQ_INPROGRESS;
 435 out:
 436         desc->chip->eoi(irq);
 437         desc = irq_remap_to_desc(irq, desc);
 438
 439         spin_unlock(&desc->lock);
 440 }
 441
 442 /**
 443  *      handle_edge_irq - edge type IRQ handler
 444  *      @irq:   the interrupt number
 445  *      @desc:  the interrupt description structure for this irq
 446  *
 447  *      Interrupt occures on the falling and/or rising edge of a hardware
 448  *      signal. The occurence is latched into the irq controller hardware
 449  *      and must be acked in order to be reenabled. After the ack another
 450  *      interrupt can happen on the same source even before the first one
 451  *      is handled by the assosiacted event handler. If this happens it
 452  *      might be necessary to disable (mask) the interrupt depending on the
 453  *      controller hardware. This requires to reenable the interrupt inside
 454  *      of the loop which handles the interrupts which have arrived while
 455  *      the handler was running. If all pending interrupts are handled, the
 456  *      loop is left.
 457  */
 458 void
 459 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
 460 {
 461         spin_lock(&desc->lock);
 462
 463         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 464
 465         /*
 466          * If we're currently running this IRQ, or its disabled,
 467          * we shouldn't process the IRQ. Mark it pending, handle
 468          * the necessary masking and go out
 469          */
 470         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 471                     !desc->action)) {
 472                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 473                 mask_ack_irq(desc, irq);
 474                 desc = irq_remap_to_desc(irq, desc);
 475                 goto out_unlock;
 476         }
 477         kstat_incr_irqs_this_cpu(irq, desc);
 478
 479         /* Start handling the irq */
 480         if (desc->chip->ack)
 481                 desc->chip->ack(irq);
 482         desc = irq_remap_to_desc(irq, desc);
 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                 desc = irq_remap_to_desc(irq, desc);
 546         }
 547 }
 548
 549 void
 550 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
 551                   const char *name)
 552 {
 553         struct irq_desc *desc = irq_to_desc(irq);
 554         unsigned long flags;
 555
 556         if (!desc) {
 557                 printk(KERN_ERR
 558                        "Trying to install type control for IRQ%d\n", irq);
 559                 return;
 560         }
 561
 562         if (!handle)
 563                 handle = handle_bad_irq;
 564         else if (desc->chip == &no_irq_chip) {
 565                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 566                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
 567                 /*
 568                  * Some ARM implementations install a handler for really dumb
 569                  * interrupt hardware without setting an irq_chip. This worked
 570                  * with the ARM no_irq_chip but the check in setup_irq would
 571                  * prevent us to setup the interrupt at all. Switch it to
 572                  * dummy_irq_chip for easy transition.
 573                  */
 574                 desc->chip = &dummy_irq_chip;
 575         }
 576
 577         spin_lock_irqsave(&desc->lock, flags);
 578
 579         /* Uninstall? */
 580         if (handle == handle_bad_irq) {
 581                 if (desc->chip != &no_irq_chip) {
 582                         mask_ack_irq(desc, irq);
 583                         desc = irq_remap_to_desc(irq, desc);
 584                 }
 585                 desc->status |= IRQ_DISABLED;
 586                 desc->depth = 1;
 587         }
 588         desc->handle_irq = handle;
 589         desc->name = name;
 590
 591         if (handle != handle_bad_irq && is_chained) {
 592                 desc->status &= ~IRQ_DISABLED;
 593                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 594                 desc->depth = 0;
 595                 desc->chip->startup(irq);
 596         }
 597         spin_unlock_irqrestore(&desc->lock, flags);
 598 }
 599 EXPORT_SYMBOL_GPL(__set_irq_handler);
 600
 601 void
 602 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 603                          irq_flow_handler_t handle)
 604 {
 605         set_irq_chip(irq, chip);
 606         __set_irq_handler(irq, handle, 0, NULL);
 607 }
 608
 609 void
 610 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
 611                               irq_flow_handler_t handle, const char *name)
 612 {
 613         set_irq_chip(irq, chip);
 614         __set_irq_handler(irq, handle, 0, name);
 615 }
 616
 617 void __init set_irq_noprobe(unsigned int irq)
 618 {
 619         struct irq_desc *desc = irq_to_desc(irq);
 620         unsigned long flags;
 621
 622         if (!desc) {
 623                 printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);
 624                 return;
 625         }
 626
 627         spin_lock_irqsave(&desc->lock, flags);
 628         desc->status |= IRQ_NOPROBE;
 629         spin_unlock_irqrestore(&desc->lock, flags);
 630 }
 631
 632 void __init set_irq_probe(unsigned int irq)
 633 {
 634         struct irq_desc *desc = irq_to_desc(irq);
 635         unsigned long flags;
 636
 637         if (!desc) {
 638                 printk(KERN_ERR "Trying to mark IRQ%d probeable\n", irq);
 639                 return;
 640         }
 641
 642         spin_lock_irqsave(&desc->lock, flags);
 643         desc->status &= ~IRQ_NOPROBE;
 644         spin_unlock_irqrestore(&desc->lock, flags);
 645 }