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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                 desc->chip->ack(irq);
 294         }
 295 }
 296
 297 /**
 298  *      handle_simple_irq - Simple and software-decoded IRQs.
 299  *      @irq:   the interrupt number
 300  *      @desc:  the interrupt description structure for this irq
 301  *
 302  *      Simple interrupts are either sent from a demultiplexing interrupt
 303  *      handler or come from hardware, where no interrupt hardware control
 304  *      is necessary.
 305  *
 306  *      Note: The caller is expected to handle the ack, clear, mask and
 307  *      unmask issues if necessary.
 308  */
 309 void
 310 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
 311 {
 312         struct irqaction *action;
 313         irqreturn_t action_ret;
 314
 315         spin_lock(&desc->lock);
 316
 317         if (unlikely(desc->status & IRQ_INPROGRESS))
 318                 goto out_unlock;
 319         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 320         kstat_incr_irqs_this_cpu(irq, desc);
 321
 322         action = desc->action;
 323         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 324                 goto out_unlock;
 325
 326         desc->status |= IRQ_INPROGRESS;
 327         spin_unlock(&desc->lock);
 328
 329         action_ret = handle_IRQ_event(irq, action);
 330         if (!noirqdebug)
 331                 note_interrupt(irq, desc, action_ret);
 332
 333         spin_lock(&desc->lock);
 334         desc->status &= ~IRQ_INPROGRESS;
 335 out_unlock:
 336         spin_unlock(&desc->lock);
 337 }
 338
 339 /**
 340  *      handle_level_irq - Level type irq handler
 341  *      @irq:   the interrupt number
 342  *      @desc:  the interrupt description structure for this irq
 343  *
 344  *      Level type interrupts are active as long as the hardware line has
 345  *      the active level. This may require to mask the interrupt and unmask
 346  *      it after the associated handler has acknowledged the device, so the
 347  *      interrupt line is back to inactive.
 348  */
 349 void
 350 handle_level_irq(unsigned int irq, struct irq_desc *desc)
 351 {
 352         struct irqaction *action;
 353         irqreturn_t action_ret;
 354
 355         spin_lock(&desc->lock);
 356         mask_ack_irq(desc, irq);
 357         desc = irq_remap_to_desc(irq, desc);
 358
 359         if (unlikely(desc->status & IRQ_INPROGRESS))
 360                 goto out_unlock;
 361         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 362         kstat_incr_irqs_this_cpu(irq, 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_incr_irqs_this_cpu(irq, 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         desc = irq_remap_to_desc(irq, desc);
 436
 437         spin_unlock(&desc->lock);
 438 }
 439
 440 /**
 441  *      handle_edge_irq - edge type IRQ handler
 442  *      @irq:   the interrupt number
 443  *      @desc:  the interrupt description structure for this irq
 444  *
 445  *      Interrupt occures on the falling and/or rising edge of a hardware
 446  *      signal. The occurence is latched into the irq controller hardware
 447  *      and must be acked in order to be reenabled. After the ack another
 448  *      interrupt can happen on the same source even before the first one
 449  *      is handled by the assosiacted event handler. If this happens it
 450  *      might be necessary to disable (mask) the interrupt depending on the
 451  *      controller hardware. This requires to reenable the interrupt inside
 452  *      of the loop which handles the interrupts which have arrived while
 453  *      the handler was running. If all pending interrupts are handled, the
 454  *      loop is left.
 455  */
 456 void
 457 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
 458 {
 459         spin_lock(&desc->lock);
 460
 461         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 462
 463         /*
 464          * If we're currently running this IRQ, or its disabled,
 465          * we shouldn't process the IRQ. Mark it pending, handle
 466          * the necessary masking and go out
 467          */
 468         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 469                     !desc->action)) {
 470                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 471                 mask_ack_irq(desc, irq);
 472                 desc = irq_remap_to_desc(irq, desc);
 473                 goto out_unlock;
 474         }
 475         kstat_incr_irqs_this_cpu(irq, desc);
 476
 477         /* Start handling the irq */
 478         desc->chip->ack(irq);
 479         desc = irq_remap_to_desc(irq, desc);
 480
 481         /* Mark the IRQ currently in progress.*/
 482         desc->status |= IRQ_INPROGRESS;
 483
 484         do {
 485                 struct irqaction *action = desc->action;
 486                 irqreturn_t action_ret;
 487
 488                 if (unlikely(!action)) {
 489                         desc->chip->mask(irq);
 490                         goto out_unlock;
 491                 }
 492
 493                 /*
 494                  * When another irq arrived while we were handling
 495                  * one, we could have masked the irq.
 496                  * Renable it, if it was not disabled in meantime.
 497                  */
 498                 if (unlikely((desc->status &
 499                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 500                               (IRQ_PENDING | IRQ_MASKED))) {
 501                         desc->chip->unmask(irq);
 502                         desc->status &= ~IRQ_MASKED;
 503                 }
 504
 505                 desc->status &= ~IRQ_PENDING;
 506                 spin_unlock(&desc->lock);
 507                 action_ret = handle_IRQ_event(irq, action);
 508                 if (!noirqdebug)
 509                         note_interrupt(irq, desc, action_ret);
 510                 spin_lock(&desc->lock);
 511
 512         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 513
 514         desc->status &= ~IRQ_INPROGRESS;
 515 out_unlock:
 516         spin_unlock(&desc->lock);
 517 }
 518
 519 /**
 520  *      handle_percpu_IRQ - Per CPU local irq handler
 521  *      @irq:   the interrupt number
 522  *      @desc:  the interrupt description structure for this irq
 523  *
 524  *      Per CPU interrupts on SMP machines without locking requirements
 525  */
 526 void
 527 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
 528 {
 529         irqreturn_t action_ret;
 530
 531         kstat_incr_irqs_this_cpu(irq, desc);
 532
 533         if (desc->chip->ack)
 534                 desc->chip->ack(irq);
 535
 536         action_ret = handle_IRQ_event(irq, desc->action);
 537         if (!noirqdebug)
 538                 note_interrupt(irq, desc, action_ret);
 539
 540         if (desc->chip->eoi) {
 541                 desc->chip->eoi(irq);
 542                 desc = irq_remap_to_desc(irq, desc);
 543         }
 544 }
 545
 546 void
 547 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
 548                   const char *name)
 549 {
 550         struct irq_desc *desc = irq_to_desc(irq);
 551         unsigned long flags;
 552
 553         if (!desc) {
 554                 printk(KERN_ERR
 555                        "Trying to install type control for IRQ%d\n", irq);
 556                 return;
 557         }
 558
 559         if (!handle)
 560                 handle = handle_bad_irq;
 561         else if (desc->chip == &no_irq_chip) {
 562                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 563                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
 564                 /*
 565                  * Some ARM implementations install a handler for really dumb
 566                  * interrupt hardware without setting an irq_chip. This worked
 567                  * with the ARM no_irq_chip but the check in setup_irq would
 568                  * prevent us to setup the interrupt at all. Switch it to
 569                  * dummy_irq_chip for easy transition.
 570                  */
 571                 desc->chip = &dummy_irq_chip;
 572         }
 573
 574         spin_lock_irqsave(&desc->lock, flags);
 575
 576         /* Uninstall? */
 577         if (handle == handle_bad_irq) {
 578                 if (desc->chip != &no_irq_chip) {
 579                         mask_ack_irq(desc, irq);
 580                         desc = irq_remap_to_desc(irq, desc);
 581                 }
 582                 desc->status |= IRQ_DISABLED;
 583                 desc->depth = 1;
 584         }
 585         desc->handle_irq = handle;
 586         desc->name = name;
 587
 588         if (handle != handle_bad_irq && is_chained) {
 589                 desc->status &= ~IRQ_DISABLED;
 590                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 591                 desc->depth = 0;
 592                 desc->chip->startup(irq);
 593         }
 594         spin_unlock_irqrestore(&desc->lock, flags);
 595 }
 596
 597 void
 598 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 599                          irq_flow_handler_t handle)
 600 {
 601         set_irq_chip(irq, chip);
 602         __set_irq_handler(irq, handle, 0, NULL);
 603 }
 604
 605 void
 606 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
 607                               irq_flow_handler_t handle, const char *name)
 608 {
 609         set_irq_chip(irq, chip);
 610         __set_irq_handler(irq, handle, 0, name);
 611 }
 612
 613 void __init set_irq_noprobe(unsigned int irq)
 614 {
 615         struct irq_desc *desc = irq_to_desc(irq);
 616         unsigned long flags;
 617
 618         if (!desc) {
 619                 printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);
 620                 return;
 621         }
 622
 623         spin_lock_irqsave(&desc->lock, flags);
 624         desc->status |= IRQ_NOPROBE;
 625         spin_unlock_irqrestore(&desc->lock, flags);
 626 }
 627
 628 void __init set_irq_probe(unsigned int irq)
 629 {
 630         struct irq_desc *desc = irq_to_desc(irq);
 631         unsigned long flags;
 632
 633         if (!desc) {
 634                 printk(KERN_ERR "Trying to mark IRQ%d probeable\n", irq);
 635                 return;
 636         }
 637
 638         spin_lock_irqsave(&desc->lock, flags);
 639         desc->status &= ~IRQ_NOPROBE;
 640         spin_unlock_irqrestore(&desc->lock, flags);
 641 }