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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 = irq_to_desc(irq);
  28         unsigned long flags;
  29
  30         if (!desc) {
  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         spin_lock_irqsave(&desc->lock, flags);
  37         desc->status = IRQ_DISABLED;
  38         desc->chip = &no_irq_chip;
  39         desc->handle_irq = handle_bad_irq;
  40         desc->depth = 1;
  41         desc->msi_desc = NULL;
  42         desc->handler_data = NULL;
  43         desc->chip_data = NULL;
  44         desc->action = NULL;
  45         desc->irq_count = 0;
  46         desc->irqs_unhandled = 0;
  47 #ifdef CONFIG_SMP
  48         cpus_setall(desc->affinity);
  49 #endif
  50         spin_unlock_irqrestore(&desc->lock, flags);
  51 }
  52
  53 /**
  54  *      dynamic_irq_cleanup - cleanup a dynamically allocated irq
  55  *      @irq:   irq number to initialize
  56  */
  57 void dynamic_irq_cleanup(unsigned int irq)
  58 {
  59         struct irq_desc *desc = irq_to_desc(irq);
  60         unsigned long flags;
  61
  62         if (!desc) {
  63                 WARN(1, KERN_ERR "Trying to cleanup invalid IRQ%d\n", irq);
  64                 return;
  65         }
  66
  67         spin_lock_irqsave(&desc->lock, flags);
  68         if (desc->action) {
  69                 spin_unlock_irqrestore(&desc->lock, flags);
  70                 WARN(1, KERN_ERR "Destroying IRQ%d without calling free_irq\n",
  71                         irq);
  72                 return;
  73         }
  74         desc->msi_desc = NULL;
  75         desc->handler_data = NULL;
  76         desc->chip_data = NULL;
  77         desc->handle_irq = handle_bad_irq;
  78         desc->chip = &no_irq_chip;
  79         spin_unlock_irqrestore(&desc->lock, flags);
  80 }
  81
  82
  83 /**
  84  *      set_irq_chip - set the irq chip for an irq
  85  *      @irq:   irq number
  86  *      @chip:  pointer to irq chip description structure
  87  */
  88 int set_irq_chip(unsigned int irq, struct irq_chip *chip)
  89 {
  90         struct irq_desc *desc = irq_to_desc(irq);
  91         unsigned long flags;
  92
  93         if (!desc) {
  94                 WARN(1, KERN_ERR "Trying to install chip for IRQ%d\n", irq);
  95                 return -EINVAL;
  96         }
  97
  98         if (!chip)
  99                 chip = &no_irq_chip;
 100
 101         spin_lock_irqsave(&desc->lock, flags);
 102         irq_chip_set_defaults(chip);
 103         desc->chip = chip;
 104         spin_unlock_irqrestore(&desc->lock, flags);
 105
 106         return 0;
 107 }
 108 EXPORT_SYMBOL(set_irq_chip);
 109
 110 /**
 111  *      set_irq_type - set the irq trigger type for an irq
 112  *      @irq:   irq number
 113  *      @type:  IRQ_TYPE_{LEVEL,EDGE}_* value - see include/linux/irq.h
 114  */
 115 int set_irq_type(unsigned int irq, unsigned int type)
 116 {
 117         struct irq_desc *desc = irq_to_desc(irq);
 118         unsigned long flags;
 119         int ret = -ENXIO;
 120
 121         if (!desc) {
 122                 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
 123                 return -ENODEV;
 124         }
 125
 126         if (type == IRQ_TYPE_NONE)
 127                 return 0;
 128
 129         spin_lock_irqsave(&desc->lock, flags);
 130         ret = __irq_set_trigger(desc, irq, flags);
 131         spin_unlock_irqrestore(&desc->lock, flags);
 132         return ret;
 133 }
 134 EXPORT_SYMBOL(set_irq_type);
 135
 136 /**
 137  *      set_irq_data - set irq type data for an irq
 138  *      @irq:   Interrupt number
 139  *      @data:  Pointer to interrupt specific data
 140  *
 141  *      Set the hardware irq controller data for an irq
 142  */
 143 int set_irq_data(unsigned int irq, void *data)
 144 {
 145         struct irq_desc *desc = irq_to_desc(irq);
 146         unsigned long flags;
 147
 148         if (!desc) {
 149                 printk(KERN_ERR
 150                        "Trying to install controller data for IRQ%d\n", irq);
 151                 return -EINVAL;
 152         }
 153
 154         spin_lock_irqsave(&desc->lock, flags);
 155         desc->handler_data = data;
 156         spin_unlock_irqrestore(&desc->lock, flags);
 157         return 0;
 158 }
 159 EXPORT_SYMBOL(set_irq_data);
 160
 161 /**
 162  *      set_irq_data - set irq type data for an irq
 163  *      @irq:   Interrupt number
 164  *      @entry: Pointer to MSI descriptor data
 165  *
 166  *      Set the hardware irq controller data for an irq
 167  */
 168 int set_irq_msi(unsigned int irq, struct msi_desc *entry)
 169 {
 170         struct irq_desc *desc = irq_to_desc(irq);
 171         unsigned long flags;
 172
 173         if (!desc) {
 174                 printk(KERN_ERR
 175                        "Trying to install msi data for IRQ%d\n", irq);
 176                 return -EINVAL;
 177         }
 178
 179         spin_lock_irqsave(&desc->lock, flags);
 180         desc->msi_desc = entry;
 181         if (entry)
 182                 entry->irq = irq;
 183         spin_unlock_irqrestore(&desc->lock, flags);
 184         return 0;
 185 }
 186
 187 /**
 188  *      set_irq_chip_data - set irq chip data for an irq
 189  *      @irq:   Interrupt number
 190  *      @data:  Pointer to chip specific data
 191  *
 192  *      Set the hardware irq chip data for an irq
 193  */
 194 int set_irq_chip_data(unsigned int irq, void *data)
 195 {
 196         struct irq_desc *desc = irq_to_desc(irq);
 197         unsigned long flags;
 198
 199         if (!desc) {
 200                 printk(KERN_ERR
 201                        "Trying to install chip data for IRQ%d\n", irq);
 202                 return -EINVAL;
 203         }
 204
 205         if (!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 = irq_to_desc(irq);
 224
 225         desc->chip->unmask(irq);
 226         desc->status &= ~IRQ_MASKED;
 227 }
 228
 229 /*
 230  * default disable function
 231  */
 232 static void default_disable(unsigned int irq)
 233 {
 234 }
 235
 236 /*
 237  * default startup function
 238  */
 239 static unsigned int default_startup(unsigned int irq)
 240 {
 241         struct irq_desc *desc = irq_to_desc(irq);
 242
 243         desc->chip->enable(irq);
 244         return 0;
 245 }
 246
 247 /*
 248  * default shutdown function
 249  */
 250 static void default_shutdown(unsigned int irq)
 251 {
 252         struct irq_desc *desc = irq_to_desc(irq);
 253
 254         desc->chip->mask(irq);
 255         desc->status |= IRQ_MASKED;
 256 }
 257
 258 /*
 259  * Fixup enable/disable function pointers
 260  */
 261 void irq_chip_set_defaults(struct irq_chip *chip)
 262 {
 263         if (!chip->enable)
 264                 chip->enable = default_enable;
 265         if (!chip->disable)
 266                 chip->disable = default_disable;
 267         if (!chip->startup)
 268                 chip->startup = default_startup;
 269         /*
 270          * We use chip->disable, when the user provided its own. When
 271          * we have default_disable set for chip->disable, then we need
 272          * to use default_shutdown, otherwise the irq line is not
 273          * disabled on free_irq():
 274          */
 275         if (!chip->shutdown)
 276                 chip->shutdown = chip->disable != default_disable ?
 277                         chip->disable : default_shutdown;
 278         if (!chip->name)
 279                 chip->name = chip->typename;
 280         if (!chip->end)
 281                 chip->end = dummy_irq_chip.end;
 282 }
 283
 284 static inline void mask_ack_irq(struct irq_desc *desc, int irq)
 285 {
 286         if (desc->chip->mask_ack)
 287                 desc->chip->mask_ack(irq);
 288         else {
 289                 desc->chip->mask(irq);
 290                 desc->chip->ack(irq);
 291         }
 292 }
 293
 294 /**
 295  *      handle_simple_irq - Simple and software-decoded IRQs.
 296  *      @irq:   the interrupt number
 297  *      @desc:  the interrupt description structure for this irq
 298  *
 299  *      Simple interrupts are either sent from a demultiplexing interrupt
 300  *      handler or come from hardware, where no interrupt hardware control
 301  *      is necessary.
 302  *
 303  *      Note: The caller is expected to handle the ack, clear, mask and
 304  *      unmask issues if necessary.
 305  */
 306 void
 307 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
 308 {
 309         struct irqaction *action;
 310         irqreturn_t action_ret;
 311
 312         spin_lock(&desc->lock);
 313
 314         if (unlikely(desc->status & IRQ_INPROGRESS))
 315                 goto out_unlock;
 316         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 317         kstat_incr_irqs_this_cpu(irq, desc);
 318
 319         action = desc->action;
 320         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 321                 goto out_unlock;
 322
 323         desc->status |= IRQ_INPROGRESS;
 324         spin_unlock(&desc->lock);
 325
 326         action_ret = handle_IRQ_event(irq, action);
 327         if (!noirqdebug)
 328                 note_interrupt(irq, desc, action_ret);
 329
 330         spin_lock(&desc->lock);
 331         desc->status &= ~IRQ_INPROGRESS;
 332 out_unlock:
 333         spin_unlock(&desc->lock);
 334 }
 335
 336 /**
 337  *      handle_level_irq - Level type irq handler
 338  *      @irq:   the interrupt number
 339  *      @desc:  the interrupt description structure for this irq
 340  *
 341  *      Level type interrupts are active as long as the hardware line has
 342  *      the active level. This may require to mask the interrupt and unmask
 343  *      it after the associated handler has acknowledged the device, so the
 344  *      interrupt line is back to inactive.
 345  */
 346 void
 347 handle_level_irq(unsigned int irq, struct irq_desc *desc)
 348 {
 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_incr_irqs_this_cpu(irq, desc);
 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         struct irqaction *action;
 397         irqreturn_t action_ret;
 398
 399         spin_lock(&desc->lock);
 400
 401         if (unlikely(desc->status & IRQ_INPROGRESS))
 402                 goto out;
 403
 404         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 405         kstat_incr_irqs_this_cpu(irq, desc);
 406
 407         /*
 408          * If its disabled or no action available
 409          * then mask it and get out of here:
 410          */
 411         action = desc->action;
 412         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 413                 desc->status |= IRQ_PENDING;
 414                 if (desc->chip->mask)
 415                         desc->chip->mask(irq);
 416                 goto out;
 417         }
 418
 419         desc->status |= IRQ_INPROGRESS;
 420         desc->status &= ~IRQ_PENDING;
 421         spin_unlock(&desc->lock);
 422
 423         action_ret = handle_IRQ_event(irq, action);
 424         if (!noirqdebug)
 425                 note_interrupt(irq, desc, action_ret);
 426
 427         spin_lock(&desc->lock);
 428         desc->status &= ~IRQ_INPROGRESS;
 429 out:
 430         desc->chip->eoi(irq);
 431
 432         spin_unlock(&desc->lock);
 433 }
 434
 435 /**
 436  *      handle_edge_irq - edge type IRQ handler
 437  *      @irq:   the interrupt number
 438  *      @desc:  the interrupt description structure for this irq
 439  *
 440  *      Interrupt occures on the falling and/or rising edge of a hardware
 441  *      signal. The occurence is latched into the irq controller hardware
 442  *      and must be acked in order to be reenabled. After the ack another
 443  *      interrupt can happen on the same source even before the first one
 444  *      is handled by the assosiacted event handler. If this happens it
 445  *      might be necessary to disable (mask) the interrupt depending on the
 446  *      controller hardware. This requires to reenable the interrupt inside
 447  *      of the loop which handles the interrupts which have arrived while
 448  *      the handler was running. If all pending interrupts are handled, the
 449  *      loop is left.
 450  */
 451 void
 452 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
 453 {
 454         spin_lock(&desc->lock);
 455
 456         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 457
 458         /*
 459          * If we're currently running this IRQ, or its disabled,
 460          * we shouldn't process the IRQ. Mark it pending, handle
 461          * the necessary masking and go out
 462          */
 463         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 464                     !desc->action)) {
 465                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 466                 mask_ack_irq(desc, irq);
 467                 goto out_unlock;
 468         }
 469         kstat_incr_irqs_this_cpu(irq, desc);
 470
 471         /* Start handling the irq */
 472         desc->chip->ack(irq);
 473
 474         /* Mark the IRQ currently in progress.*/
 475         desc->status |= IRQ_INPROGRESS;
 476
 477         do {
 478                 struct irqaction *action = desc->action;
 479                 irqreturn_t action_ret;
 480
 481                 if (unlikely(!action)) {
 482                         desc->chip->mask(irq);
 483                         goto out_unlock;
 484                 }
 485
 486                 /*
 487                  * When another irq arrived while we were handling
 488                  * one, we could have masked the irq.
 489                  * Renable it, if it was not disabled in meantime.
 490                  */
 491                 if (unlikely((desc->status &
 492                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 493                               (IRQ_PENDING | IRQ_MASKED))) {
 494                         desc->chip->unmask(irq);
 495                         desc->status &= ~IRQ_MASKED;
 496                 }
 497
 498                 desc->status &= ~IRQ_PENDING;
 499                 spin_unlock(&desc->lock);
 500                 action_ret = handle_IRQ_event(irq, action);
 501                 if (!noirqdebug)
 502                         note_interrupt(irq, desc, action_ret);
 503                 spin_lock(&desc->lock);
 504
 505         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 506
 507         desc->status &= ~IRQ_INPROGRESS;
 508 out_unlock:
 509         spin_unlock(&desc->lock);
 510 }
 511
 512 /**
 513  *      handle_percpu_IRQ - Per CPU local irq handler
 514  *      @irq:   the interrupt number
 515  *      @desc:  the interrupt description structure for this irq
 516  *
 517  *      Per CPU interrupts on SMP machines without locking requirements
 518  */
 519 void
 520 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
 521 {
 522         irqreturn_t action_ret;
 523
 524         kstat_incr_irqs_this_cpu(irq, desc);
 525
 526         if (desc->chip->ack)
 527                 desc->chip->ack(irq);
 528
 529         action_ret = handle_IRQ_event(irq, desc->action);
 530         if (!noirqdebug)
 531                 note_interrupt(irq, desc, action_ret);
 532
 533         if (desc->chip->eoi)
 534                 desc->chip->eoi(irq);
 535 }
 536
 537 void
 538 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
 539                   const char *name)
 540 {
 541         struct irq_desc *desc = irq_to_desc(irq);
 542         unsigned long flags;
 543
 544         if (!desc) {
 545                 printk(KERN_ERR
 546                        "Trying to install type control for IRQ%d\n", irq);
 547                 return;
 548         }
 549
 550         if (!handle)
 551                 handle = handle_bad_irq;
 552         else if (desc->chip == &no_irq_chip) {
 553                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 554                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
 555                 /*
 556                  * Some ARM implementations install a handler for really dumb
 557                  * interrupt hardware without setting an irq_chip. This worked
 558                  * with the ARM no_irq_chip but the check in setup_irq would
 559                  * prevent us to setup the interrupt at all. Switch it to
 560                  * dummy_irq_chip for easy transition.
 561                  */
 562                 desc->chip = &dummy_irq_chip;
 563         }
 564
 565         spin_lock_irqsave(&desc->lock, flags);
 566
 567         /* Uninstall? */
 568         if (handle == handle_bad_irq) {
 569                 if (desc->chip != &no_irq_chip)
 570                         mask_ack_irq(desc, irq);
 571                 desc->status |= IRQ_DISABLED;
 572                 desc->depth = 1;
 573         }
 574         desc->handle_irq = handle;
 575         desc->name = name;
 576
 577         if (handle != handle_bad_irq && is_chained) {
 578                 desc->status &= ~IRQ_DISABLED;
 579                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 580                 desc->depth = 0;
 581                 desc->chip->startup(irq);
 582         }
 583         spin_unlock_irqrestore(&desc->lock, flags);
 584 }
 585
 586 void
 587 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 588                          irq_flow_handler_t handle)
 589 {
 590         set_irq_chip(irq, chip);
 591         __set_irq_handler(irq, handle, 0, NULL);
 592 }
 593
 594 void
 595 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
 596                               irq_flow_handler_t handle, const char *name)
 597 {
 598         set_irq_chip(irq, chip);
 599         __set_irq_handler(irq, handle, 0, name);
 600 }
 601
 602 void __init set_irq_noprobe(unsigned int irq)
 603 {
 604         struct irq_desc *desc = irq_to_desc(irq);
 605         unsigned long flags;
 606
 607         if (!desc) {
 608                 printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);
 609                 return;
 610         }
 611
 612         spin_lock_irqsave(&desc->lock, flags);
 613         desc->status |= IRQ_NOPROBE;
 614         spin_unlock_irqrestore(&desc->lock, flags);
 615 }
 616
 617 void __init set_irq_probe(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 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 }