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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         desc->name = NULL;
  80         spin_unlock_irqrestore(&desc->lock, flags);
  81 }
  82
  83
  84 /**
  85  *      set_irq_chip - set the irq chip for an irq
  86  *      @irq:   irq number
  87  *      @chip:  pointer to irq chip description structure
  88  */
  89 int set_irq_chip(unsigned int irq, struct irq_chip *chip)
  90 {
  91         struct irq_desc *desc = irq_to_desc(irq);
  92         unsigned long flags;
  93
  94         if (!desc) {
  95                 WARN(1, KERN_ERR "Trying to install chip for IRQ%d\n", irq);
  96                 return -EINVAL;
  97         }
  98
  99         if (!chip)
 100                 chip = &no_irq_chip;
 101
 102         spin_lock_irqsave(&desc->lock, flags);
 103         irq_chip_set_defaults(chip);
 104         desc->chip = chip;
 105         spin_unlock_irqrestore(&desc->lock, flags);
 106
 107         return 0;
 108 }
 109 EXPORT_SYMBOL(set_irq_chip);
 110
 111 /**
 112  *      set_irq_type - set the irq trigger type for an irq
 113  *      @irq:   irq number
 114  *      @type:  IRQ_TYPE_{LEVEL,EDGE}_* value - see include/linux/irq.h
 115  */
 116 int set_irq_type(unsigned int irq, unsigned int type)
 117 {
 118         struct irq_desc *desc = irq_to_desc(irq);
 119         unsigned long flags;
 120         int ret = -ENXIO;
 121
 122         if (!desc) {
 123                 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
 124                 return -ENODEV;
 125         }
 126
 127         if (type == IRQ_TYPE_NONE)
 128                 return 0;
 129
 130         spin_lock_irqsave(&desc->lock, flags);
 131         ret = __irq_set_trigger(desc, irq, type);
 132         spin_unlock_irqrestore(&desc->lock, flags);
 133         return ret;
 134 }
 135 EXPORT_SYMBOL(set_irq_type);
 136
 137 /**
 138  *      set_irq_data - set irq type data for an irq
 139  *      @irq:   Interrupt number
 140  *      @data:  Pointer to interrupt specific data
 141  *
 142  *      Set the hardware irq controller data for an irq
 143  */
 144 int set_irq_data(unsigned int irq, void *data)
 145 {
 146         struct irq_desc *desc = irq_to_desc(irq);
 147         unsigned long flags;
 148
 149         if (!desc) {
 150                 printk(KERN_ERR
 151                        "Trying to install controller data for IRQ%d\n", irq);
 152                 return -EINVAL;
 153         }
 154
 155         spin_lock_irqsave(&desc->lock, flags);
 156         desc->handler_data = data;
 157         spin_unlock_irqrestore(&desc->lock, flags);
 158         return 0;
 159 }
 160 EXPORT_SYMBOL(set_irq_data);
 161
 162 /**
 163  *      set_irq_data - set irq type data for an irq
 164  *      @irq:   Interrupt number
 165  *      @entry: Pointer to MSI descriptor data
 166  *
 167  *      Set the hardware irq controller data for an irq
 168  */
 169 int set_irq_msi(unsigned int irq, struct msi_desc *entry)
 170 {
 171         struct irq_desc *desc = irq_to_desc(irq);
 172         unsigned long flags;
 173
 174         if (!desc) {
 175                 printk(KERN_ERR
 176                        "Trying to install msi data for IRQ%d\n", irq);
 177                 return -EINVAL;
 178         }
 179
 180         spin_lock_irqsave(&desc->lock, flags);
 181         desc->msi_desc = entry;
 182         if (entry)
 183                 entry->irq = irq;
 184         spin_unlock_irqrestore(&desc->lock, flags);
 185         return 0;
 186 }
 187
 188 /**
 189  *      set_irq_chip_data - set irq chip data for an irq
 190  *      @irq:   Interrupt number
 191  *      @data:  Pointer to chip specific data
 192  *
 193  *      Set the hardware irq chip data for an irq
 194  */
 195 int set_irq_chip_data(unsigned int irq, void *data)
 196 {
 197         struct irq_desc *desc = irq_to_desc(irq);
 198         unsigned long flags;
 199
 200         if (!desc) {
 201                 printk(KERN_ERR
 202                        "Trying to install chip data for IRQ%d\n", irq);
 203                 return -EINVAL;
 204         }
 205
 206         if (!desc->chip) {
 207                 printk(KERN_ERR "BUG: bad set_irq_chip_data(IRQ#%d)\n", irq);
 208                 return -EINVAL;
 209         }
 210
 211         spin_lock_irqsave(&desc->lock, flags);
 212         desc->chip_data = data;
 213         spin_unlock_irqrestore(&desc->lock, flags);
 214
 215         return 0;
 216 }
 217 EXPORT_SYMBOL(set_irq_chip_data);
 218
 219 /*
 220  * default enable function
 221  */
 222 static void default_enable(unsigned int irq)
 223 {
 224         struct irq_desc *desc = irq_to_desc(irq);
 225
 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 = irq_to_desc(irq);
 243
 244         desc->chip->enable(irq);
 245         return 0;
 246 }
 247
 248 /*
 249  * default shutdown function
 250  */
 251 static void default_shutdown(unsigned int irq)
 252 {
 253         struct irq_desc *desc = irq_to_desc(irq);
 254
 255         desc->chip->mask(irq);
 256         desc->status |= IRQ_MASKED;
 257 }
 258
 259 /*
 260  * Fixup enable/disable function pointers
 261  */
 262 void irq_chip_set_defaults(struct irq_chip *chip)
 263 {
 264         if (!chip->enable)
 265                 chip->enable = default_enable;
 266         if (!chip->disable)
 267                 chip->disable = default_disable;
 268         if (!chip->startup)
 269                 chip->startup = default_startup;
 270         /*
 271          * We use chip->disable, when the user provided its own. When
 272          * we have default_disable set for chip->disable, then we need
 273          * to use default_shutdown, otherwise the irq line is not
 274          * disabled on free_irq():
 275          */
 276         if (!chip->shutdown)
 277                 chip->shutdown = chip->disable != default_disable ?
 278                         chip->disable : default_shutdown;
 279         if (!chip->name)
 280                 chip->name = chip->typename;
 281         if (!chip->end)
 282                 chip->end = dummy_irq_chip.end;
 283 }
 284
 285 static inline void mask_ack_irq(struct irq_desc *desc, int irq)
 286 {
 287         if (desc->chip->mask_ack)
 288                 desc->chip->mask_ack(irq);
 289         else {
 290                 desc->chip->mask(irq);
 291                 desc->chip->ack(irq);
 292         }
 293 }
 294
 295 /**
 296  *      handle_simple_irq - Simple and software-decoded IRQs.
 297  *      @irq:   the interrupt number
 298  *      @desc:  the interrupt description structure for this irq
 299  *
 300  *      Simple interrupts are either sent from a demultiplexing interrupt
 301  *      handler or come from hardware, where no interrupt hardware control
 302  *      is necessary.
 303  *
 304  *      Note: The caller is expected to handle the ack, clear, mask and
 305  *      unmask issues if necessary.
 306  */
 307 void
 308 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
 309 {
 310         struct irqaction *action;
 311         irqreturn_t action_ret;
 312
 313         spin_lock(&desc->lock);
 314
 315         if (unlikely(desc->status & IRQ_INPROGRESS))
 316                 goto out_unlock;
 317         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 318         kstat_incr_irqs_this_cpu(irq, desc);
 319
 320         action = desc->action;
 321         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 322                 goto out_unlock;
 323
 324         desc->status |= IRQ_INPROGRESS;
 325         spin_unlock(&desc->lock);
 326
 327         action_ret = handle_IRQ_event(irq, action);
 328         if (!noirqdebug)
 329                 note_interrupt(irq, desc, action_ret);
 330
 331         spin_lock(&desc->lock);
 332         desc->status &= ~IRQ_INPROGRESS;
 333 out_unlock:
 334         spin_unlock(&desc->lock);
 335 }
 336
 337 /**
 338  *      handle_level_irq - Level type irq handler
 339  *      @irq:   the interrupt number
 340  *      @desc:  the interrupt description structure for this irq
 341  *
 342  *      Level type interrupts are active as long as the hardware line has
 343  *      the active level. This may require to mask the interrupt and unmask
 344  *      it after the associated handler has acknowledged the device, so the
 345  *      interrupt line is back to inactive.
 346  */
 347 void
 348 handle_level_irq(unsigned int irq, struct irq_desc *desc)
 349 {
 350         struct irqaction *action;
 351         irqreturn_t action_ret;
 352
 353         spin_lock(&desc->lock);
 354         mask_ack_irq(desc, irq);
 355
 356         if (unlikely(desc->status & IRQ_INPROGRESS))
 357                 goto out_unlock;
 358         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 359         kstat_incr_irqs_this_cpu(irq, desc);
 360
 361         /*
 362          * If its disabled or no action available
 363          * keep it masked and get out of here
 364          */
 365         action = desc->action;
 366         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 367                 goto out_unlock;
 368
 369         desc->status |= IRQ_INPROGRESS;
 370         spin_unlock(&desc->lock);
 371
 372         action_ret = handle_IRQ_event(irq, action);
 373         if (!noirqdebug)
 374                 note_interrupt(irq, desc, action_ret);
 375
 376         spin_lock(&desc->lock);
 377         desc->status &= ~IRQ_INPROGRESS;
 378         if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
 379                 desc->chip->unmask(irq);
 380 out_unlock:
 381         spin_unlock(&desc->lock);
 382 }
 383
 384 /**
 385  *      handle_fasteoi_irq - irq handler for transparent controllers
 386  *      @irq:   the interrupt number
 387  *      @desc:  the interrupt description structure for this irq
 388  *
 389  *      Only a single callback will be issued to the chip: an ->eoi()
 390  *      call when the interrupt has been serviced. This enables support
 391  *      for modern forms of interrupt handlers, which handle the flow
 392  *      details in hardware, transparently.
 393  */
 394 void
 395 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 396 {
 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_incr_irqs_this_cpu(irq, desc);
 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         spin_lock(&desc->lock);
 456
 457         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 458
 459         /*
 460          * If we're currently running this IRQ, or its disabled,
 461          * we shouldn't process the IRQ. Mark it pending, handle
 462          * the necessary masking and go out
 463          */
 464         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 465                     !desc->action)) {
 466                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 467                 mask_ack_irq(desc, irq);
 468                 goto out_unlock;
 469         }
 470         kstat_incr_irqs_this_cpu(irq, desc);
 471
 472         /* Start handling the irq */
 473         desc->chip->ack(irq);
 474
 475         /* Mark the IRQ currently in progress.*/
 476         desc->status |= IRQ_INPROGRESS;
 477
 478         do {
 479                 struct irqaction *action = desc->action;
 480                 irqreturn_t action_ret;
 481
 482                 if (unlikely(!action)) {
 483                         desc->chip->mask(irq);
 484                         goto out_unlock;
 485                 }
 486
 487                 /*
 488                  * When another irq arrived while we were handling
 489                  * one, we could have masked the irq.
 490                  * Renable it, if it was not disabled in meantime.
 491                  */
 492                 if (unlikely((desc->status &
 493                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 494                               (IRQ_PENDING | IRQ_MASKED))) {
 495                         desc->chip->unmask(irq);
 496                         desc->status &= ~IRQ_MASKED;
 497                 }
 498
 499                 desc->status &= ~IRQ_PENDING;
 500                 spin_unlock(&desc->lock);
 501                 action_ret = handle_IRQ_event(irq, action);
 502                 if (!noirqdebug)
 503                         note_interrupt(irq, desc, action_ret);
 504                 spin_lock(&desc->lock);
 505
 506         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 507
 508         desc->status &= ~IRQ_INPROGRESS;
 509 out_unlock:
 510         spin_unlock(&desc->lock);
 511 }
 512
 513 /**
 514  *      handle_percpu_IRQ - Per CPU local irq handler
 515  *      @irq:   the interrupt number
 516  *      @desc:  the interrupt description structure for this irq
 517  *
 518  *      Per CPU interrupts on SMP machines without locking requirements
 519  */
 520 void
 521 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
 522 {
 523         irqreturn_t action_ret;
 524
 525         kstat_incr_irqs_this_cpu(irq, desc);
 526
 527         if (desc->chip->ack)
 528                 desc->chip->ack(irq);
 529
 530         action_ret = handle_IRQ_event(irq, desc->action);
 531         if (!noirqdebug)
 532                 note_interrupt(irq, desc, action_ret);
 533
 534         if (desc->chip->eoi)
 535                 desc->chip->eoi(irq);
 536 }
 537
 538 void
 539 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
 540                   const char *name)
 541 {
 542         struct irq_desc *desc = irq_to_desc(irq);
 543         unsigned long flags;
 544
 545         if (!desc) {
 546                 printk(KERN_ERR
 547                        "Trying to install type control for IRQ%d\n", irq);
 548                 return;
 549         }
 550
 551         if (!handle)
 552                 handle = handle_bad_irq;
 553         else if (desc->chip == &no_irq_chip) {
 554                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 555                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
 556                 /*
 557                  * Some ARM implementations install a handler for really dumb
 558                  * interrupt hardware without setting an irq_chip. This worked
 559                  * with the ARM no_irq_chip but the check in setup_irq would
 560                  * prevent us to setup the interrupt at all. Switch it to
 561                  * dummy_irq_chip for easy transition.
 562                  */
 563                 desc->chip = &dummy_irq_chip;
 564         }
 565
 566         spin_lock_irqsave(&desc->lock, flags);
 567
 568         /* Uninstall? */
 569         if (handle == handle_bad_irq) {
 570                 if (desc->chip != &no_irq_chip)
 571                         mask_ack_irq(desc, irq);
 572                 desc->status |= IRQ_DISABLED;
 573                 desc->depth = 1;
 574         }
 575         desc->handle_irq = handle;
 576         desc->name = name;
 577
 578         if (handle != handle_bad_irq && is_chained) {
 579                 desc->status &= ~IRQ_DISABLED;
 580                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 581                 desc->depth = 0;
 582                 desc->chip->startup(irq);
 583         }
 584         spin_unlock_irqrestore(&desc->lock, flags);
 585 }
 586
 587 void
 588 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 589                          irq_flow_handler_t handle)
 590 {
 591         set_irq_chip(irq, chip);
 592         __set_irq_handler(irq, handle, 0, NULL);
 593 }
 594
 595 void
 596 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
 597                               irq_flow_handler_t handle, const char *name)
 598 {
 599         set_irq_chip(irq, chip);
 600         __set_irq_handler(irq, handle, 0, name);
 601 }
 602
 603 void __init set_irq_noprobe(unsigned int irq)
 604 {
 605         struct irq_desc *desc = irq_to_desc(irq);
 606         unsigned long flags;
 607
 608         if (!desc) {
 609                 printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);
 610                 return;
 611         }
 612
 613         spin_lock_irqsave(&desc->lock, flags);
 614         desc->status |= IRQ_NOPROBE;
 615         spin_unlock_irqrestore(&desc->lock, flags);
 616 }
 617
 618 void __init set_irq_probe(unsigned int irq)
 619 {
 620         struct irq_desc *desc = irq_to_desc(irq);
 621         unsigned long flags;
 622
 623         if (!desc) {
 624                 printk(KERN_ERR "Trying to mark IRQ%d probeable\n", irq);
 625                 return;
 626         }
 627
 628         spin_lock_irqsave(&desc->lock, flags);
 629         desc->status &= ~IRQ_NOPROBE;
 630         spin_unlock_irqrestore(&desc->lock, flags);
 631 }