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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_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
 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_irqs_this_cpu(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
 359         if (unlikely(desc->status & IRQ_INPROGRESS))
 360                 goto out_unlock;
 361         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 362         kstat_irqs_this_cpu(desc)++;
 363
 364         /*
 365          * If its disabled or no action available
 366          * keep it masked and get out of here
 367          */
 368         action = desc->action;
 369         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 370                 goto out_unlock;
 371
 372         desc->status |= IRQ_INPROGRESS;
 373         spin_unlock(&desc->lock);
 374
 375         action_ret = handle_IRQ_event(irq, action);
 376         if (!noirqdebug)
 377                 note_interrupt(irq, desc, action_ret);
 378
 379         spin_lock(&desc->lock);
 380         desc->status &= ~IRQ_INPROGRESS;
 381         if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
 382                 desc->chip->unmask(irq);
 383 out_unlock:
 384         spin_unlock(&desc->lock);
 385 }
 386
 387 /**
 388  *      handle_fasteoi_irq - irq handler for transparent controllers
 389  *      @irq:   the interrupt number
 390  *      @desc:  the interrupt description structure for this irq
 391  *
 392  *      Only a single callback will be issued to the chip: an ->eoi()
 393  *      call when the interrupt has been serviced. This enables support
 394  *      for modern forms of interrupt handlers, which handle the flow
 395  *      details in hardware, transparently.
 396  */
 397 void
 398 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 399 {
 400         struct irqaction *action;
 401         irqreturn_t action_ret;
 402
 403         spin_lock(&desc->lock);
 404
 405         if (unlikely(desc->status & IRQ_INPROGRESS))
 406                 goto out;
 407
 408         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 409         kstat_irqs_this_cpu(desc)++;
 410
 411         /*
 412          * If its disabled or no action available
 413          * then mask it and get out of here:
 414          */
 415         action = desc->action;
 416         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 417                 desc->status |= IRQ_PENDING;
 418                 if (desc->chip->mask)
 419                         desc->chip->mask(irq);
 420                 goto out;
 421         }
 422
 423         desc->status |= IRQ_INPROGRESS;
 424         desc->status &= ~IRQ_PENDING;
 425         spin_unlock(&desc->lock);
 426
 427         action_ret = handle_IRQ_event(irq, action);
 428         if (!noirqdebug)
 429                 note_interrupt(irq, desc, action_ret);
 430
 431         spin_lock(&desc->lock);
 432         desc->status &= ~IRQ_INPROGRESS;
 433 out:
 434         desc->chip->eoi(irq);
 435
 436         spin_unlock(&desc->lock);
 437 }
 438
 439 /**
 440  *      handle_edge_irq - edge type IRQ handler
 441  *      @irq:   the interrupt number
 442  *      @desc:  the interrupt description structure for this irq
 443  *
 444  *      Interrupt occures on the falling and/or rising edge of a hardware
 445  *      signal. The occurence is latched into the irq controller hardware
 446  *      and must be acked in order to be reenabled. After the ack another
 447  *      interrupt can happen on the same source even before the first one
 448  *      is handled by the assosiacted event handler. If this happens it
 449  *      might be necessary to disable (mask) the interrupt depending on the
 450  *      controller hardware. This requires to reenable the interrupt inside
 451  *      of the loop which handles the interrupts which have arrived while
 452  *      the handler was running. If all pending interrupts are handled, the
 453  *      loop is left.
 454  */
 455 void
 456 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
 457 {
 458         spin_lock(&desc->lock);
 459
 460         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 461
 462         /*
 463          * If we're currently running this IRQ, or its disabled,
 464          * we shouldn't process the IRQ. Mark it pending, handle
 465          * the necessary masking and go out
 466          */
 467         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 468                     !desc->action)) {
 469                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 470                 mask_ack_irq(desc, irq);
 471                 goto out_unlock;
 472         }
 473
 474         kstat_irqs_this_cpu(desc)++;
 475
 476         /* Start handling the irq */
 477         desc->chip->ack(irq);
 478
 479         /* Mark the IRQ currently in progress.*/
 480         desc->status |= IRQ_INPROGRESS;
 481
 482         do {
 483                 struct irqaction *action = desc->action;
 484                 irqreturn_t action_ret;
 485
 486                 if (unlikely(!action)) {
 487                         desc->chip->mask(irq);
 488                         goto out_unlock;
 489                 }
 490
 491                 /*
 492                  * When another irq arrived while we were handling
 493                  * one, we could have masked the irq.
 494                  * Renable it, if it was not disabled in meantime.
 495                  */
 496                 if (unlikely((desc->status &
 497                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 498                               (IRQ_PENDING | IRQ_MASKED))) {
 499                         desc->chip->unmask(irq);
 500                         desc->status &= ~IRQ_MASKED;
 501                 }
 502
 503                 desc->status &= ~IRQ_PENDING;
 504                 spin_unlock(&desc->lock);
 505                 action_ret = handle_IRQ_event(irq, action);
 506                 if (!noirqdebug)
 507                         note_interrupt(irq, desc, action_ret);
 508                 spin_lock(&desc->lock);
 509
 510         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 511
 512         desc->status &= ~IRQ_INPROGRESS;
 513 out_unlock:
 514         spin_unlock(&desc->lock);
 515 }
 516
 517 /**
 518  *      handle_percpu_IRQ - Per CPU local irq handler
 519  *      @irq:   the interrupt number
 520  *      @desc:  the interrupt description structure for this irq
 521  *
 522  *      Per CPU interrupts on SMP machines without locking requirements
 523  */
 524 void
 525 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
 526 {
 527         irqreturn_t action_ret;
 528
 529         kstat_irqs_this_cpu(desc)++;
 530
 531         if (desc->chip->ack)
 532                 desc->chip->ack(irq);
 533
 534         action_ret = handle_IRQ_event(irq, desc->action);
 535         if (!noirqdebug)
 536                 note_interrupt(irq, desc, action_ret);
 537
 538         if (desc->chip->eoi)
 539                 desc->chip->eoi(irq);
 540 }
 541
 542 void
 543 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
 544                   const char *name)
 545 {
 546         struct irq_desc *desc;
 547         unsigned long flags;
 548
 549         if (irq >= nr_irqs) {
 550                 printk(KERN_ERR
 551                        "Trying to install type control for IRQ%d\n", irq);
 552                 return;
 553         }
 554
 555         desc = irq_to_desc(irq);
 556
 557         if (!handle)
 558                 handle = handle_bad_irq;
 559         else if (desc->chip == &no_irq_chip) {
 560                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 561                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
 562                 /*
 563                  * Some ARM implementations install a handler for really dumb
 564                  * interrupt hardware without setting an irq_chip. This worked
 565                  * with the ARM no_irq_chip but the check in setup_irq would
 566                  * prevent us to setup the interrupt at all. Switch it to
 567                  * dummy_irq_chip for easy transition.
 568                  */
 569                 desc->chip = &dummy_irq_chip;
 570         }
 571
 572         spin_lock_irqsave(&desc->lock, flags);
 573
 574         /* Uninstall? */
 575         if (handle == handle_bad_irq) {
 576                 if (desc->chip != &no_irq_chip)
 577                         mask_ack_irq(desc, irq);
 578                 desc->status |= IRQ_DISABLED;
 579                 desc->depth = 1;
 580         }
 581         desc->handle_irq = handle;
 582         desc->name = name;
 583
 584         if (handle != handle_bad_irq && is_chained) {
 585                 desc->status &= ~IRQ_DISABLED;
 586                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 587                 desc->depth = 0;
 588                 desc->chip->startup(irq);
 589         }
 590         spin_unlock_irqrestore(&desc->lock, flags);
 591 }
 592
 593 void
 594 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 595                          irq_flow_handler_t handle)
 596 {
 597         set_irq_chip(irq, chip);
 598         __set_irq_handler(irq, handle, 0, NULL);
 599 }
 600
 601 void
 602 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
 603                               irq_flow_handler_t handle, const char *name)
 604 {
 605         set_irq_chip(irq, chip);
 606         __set_irq_handler(irq, handle, 0, name);
 607 }
 608
 609 void __init set_irq_noprobe(unsigned int irq)
 610 {
 611         struct irq_desc *desc;
 612         unsigned long flags;
 613
 614         if (irq >= nr_irqs) {
 615                 printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);
 616
 617                 return;
 618         }
 619
 620         desc = irq_to_desc(irq);
 621
 622         spin_lock_irqsave(&desc->lock, flags);
 623         desc->status |= IRQ_NOPROBE;
 624         spin_unlock_irqrestore(&desc->lock, flags);
 625 }
 626
 627 void __init set_irq_probe(unsigned int irq)
 628 {
 629         struct irq_desc *desc;
 630         unsigned long flags;
 631
 632         if (irq >= nr_irqs) {
 633                 printk(KERN_ERR "Trying to mark IRQ%d probeable\n", irq);
 634
 635                 return;
 636         }
 637
 638         desc = irq_to_desc(irq);
 639
 640         spin_lock_irqsave(&desc->lock, flags);
 641         desc->status &= ~IRQ_NOPROBE;
 642         spin_unlock_irqrestore(&desc->lock, flags);
 643 }