kernel/irq/chip.c

   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_to_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_to_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_to_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_to_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_to_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_to_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;
 202         unsigned long flags;
 203
 204         desc = irq_to_desc(irq);
 205         if (irq >= nr_irqs || !desc->chip) {
 206                 printk(KERN_ERR "BUG: bad set_irq_chip_data(IRQ#%d)\n", irq);
 207                 return -EINVAL;
 208         }
 209
 210         spin_lock_irqsave(&desc->lock, flags);
 211         desc->chip_data = data;
 212         spin_unlock_irqrestore(&desc->lock, flags);
 213
 214         return 0;
 215 }
 216 EXPORT_SYMBOL(set_irq_chip_data);
 217
 218 /*
 219  * default enable function
 220  */
 221 static void default_enable(unsigned int irq)
 222 {
 223         struct irq_desc *desc;
 224
 225         desc = irq_to_desc(irq);
 226         desc->chip->unmask(irq);
 227         desc->status &= ~IRQ_MASKED;
 228 }
 229
 230 /*
 231  * default disable function
 232  */
 233 static void default_disable(unsigned int irq)
 234 {
 235 }
 236
 237 /*
 238  * default startup function
 239  */
 240 static unsigned int default_startup(unsigned int irq)
 241 {
 242         struct irq_desc *desc;
 243
 244         desc = irq_to_desc(irq);
 245         desc->chip->enable(irq);
 246
 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;
 256
 257         desc = irq_to_desc(irq);
 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                 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         const unsigned int cpu = smp_processor_id();
 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_cpu(cpu).irqs[irq]++;
 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         unsigned int cpu = smp_processor_id();
 355         struct irqaction *action;
 356         irqreturn_t action_ret;
 357
 358         spin_lock(&desc->lock);
 359         mask_ack_irq(desc, irq);
 360
 361         if (unlikely(desc->status & IRQ_INPROGRESS))
 362                 goto out_unlock;
 363         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 364         kstat_cpu(cpu).irqs[irq]++;
 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
 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         unsigned int cpu = smp_processor_id();
 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_cpu(cpu).irqs[irq]++;
 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
 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         const unsigned int cpu = smp_processor_id();
 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
 479         kstat_cpu(cpu).irqs[irq]++;
 480
 481         /* Start handling the irq */
 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_this_cpu.irqs[irq]++;
 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;
 552         unsigned long flags;
 553
 554         if (irq >= nr_irqs) {
 555                 printk(KERN_ERR
 556                        "Trying to install type control for IRQ%d\n", irq);
 557                 return;
 558         }
 559
 560         desc = irq_to_desc(irq);
 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->status |= IRQ_DISABLED;
 584                 desc->depth = 1;
 585         }
 586         desc->handle_irq = handle;
 587         desc->name = name;
 588
 589         if (handle != handle_bad_irq && is_chained) {
 590                 desc->status &= ~IRQ_DISABLED;
 591                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 592                 desc->depth = 0;
 593                 desc->chip->startup(irq);
 594         }
 595         spin_unlock_irqrestore(&desc->lock, flags);
 596 }
 597
 598 void
 599 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 600                          irq_flow_handler_t handle)
 601 {
 602         set_irq_chip(irq, chip);
 603         __set_irq_handler(irq, handle, 0, NULL);
 604 }
 605
 606 void
 607 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
 608                               irq_flow_handler_t handle, const char *name)
 609 {
 610         set_irq_chip(irq, chip);
 611         __set_irq_handler(irq, handle, 0, name);
 612 }
 613
 614 void __init set_irq_noprobe(unsigned int irq)
 615 {
 616         struct irq_desc *desc;
 617         unsigned long flags;
 618
 619         if (irq >= nr_irqs) {
 620                 printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);
 621
 622                 return;
 623         }
 624
 625         desc = irq_to_desc(irq);
 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;
 635         unsigned long flags;
 636
 637         if (irq >= nr_irqs) {
 638                 printk(KERN_ERR "Trying to mark IRQ%d probeable\n", irq);
 639
 640                 return;
 641         }
 642
 643         desc = irq_to_desc(irq);
 644
 645         spin_lock_irqsave(&desc->lock, flags);
 646         desc->status &= ~IRQ_NOPROBE;
 647         spin_unlock_irqrestore(&desc->lock, flags);
 648 }