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