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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_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_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_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 type for an irq
 115  *      @irq:   irq number
 116  *      @type:  interrupt type - see include/linux/interrupt.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_desc + irq;
 130         if (desc->chip->set_type) {
 131                 spin_lock_irqsave(&desc->lock, flags);
 132                 ret = desc->chip->set_type(irq, type);
 133                 spin_unlock_irqrestore(&desc->lock, flags);
 134         }
 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;
 149         unsigned long flags;
 150
 151         if (irq >= NR_IRQS) {
 152                 printk(KERN_ERR
 153                        "Trying to install controller data for IRQ%d\n", irq);
 154                 return -EINVAL;
 155         }
 156
 157         desc = irq_desc + irq;
 158         spin_lock_irqsave(&desc->lock, flags);
 159         desc->handler_data = data;
 160         spin_unlock_irqrestore(&desc->lock, flags);
 161         return 0;
 162 }
 163 EXPORT_SYMBOL(set_irq_data);
 164
 165 /**
 166  *      set_irq_data - set irq type data for an irq
 167  *      @irq:   Interrupt number
 168  *      @entry: Pointer to MSI descriptor data
 169  *
 170  *      Set the hardware irq controller data for an irq
 171  */
 172 int set_irq_msi(unsigned int irq, struct msi_desc *entry)
 173 {
 174         struct irq_desc *desc;
 175         unsigned long flags;
 176
 177         if (irq >= NR_IRQS) {
 178                 printk(KERN_ERR
 179                        "Trying to install msi data for IRQ%d\n", irq);
 180                 return -EINVAL;
 181         }
 182         desc = irq_desc + irq;
 183         spin_lock_irqsave(&desc->lock, flags);
 184         desc->msi_desc = entry;
 185         if (entry)
 186                 entry->irq = irq;
 187         spin_unlock_irqrestore(&desc->lock, flags);
 188         return 0;
 189 }
 190
 191 /**
 192  *      set_irq_chip_data - set irq chip data for an irq
 193  *      @irq:   Interrupt number
 194  *      @data:  Pointer to chip specific data
 195  *
 196  *      Set the hardware irq chip data for an irq
 197  */
 198 int set_irq_chip_data(unsigned int irq, void *data)
 199 {
 200         struct irq_desc *desc = irq_desc + irq;
 201         unsigned long flags;
 202
 203         if (irq >= NR_IRQS || !desc->chip) {
 204                 printk(KERN_ERR "BUG: bad set_irq_chip_data(IRQ#%d)\n", irq);
 205                 return -EINVAL;
 206         }
 207
 208         spin_lock_irqsave(&desc->lock, flags);
 209         desc->chip_data = data;
 210         spin_unlock_irqrestore(&desc->lock, flags);
 211
 212         return 0;
 213 }
 214 EXPORT_SYMBOL(set_irq_chip_data);
 215
 216 /*
 217  * default enable function
 218  */
 219 static void default_enable(unsigned int irq)
 220 {
 221         struct irq_desc *desc = irq_desc + irq;
 222
 223         desc->chip->unmask(irq);
 224         desc->status &= ~IRQ_MASKED;
 225 }
 226
 227 /*
 228  * default disable function
 229  */
 230 static void default_disable(unsigned int irq)
 231 {
 232 }
 233
 234 /*
 235  * default startup function
 236  */
 237 static unsigned int default_startup(unsigned int irq)
 238 {
 239         irq_desc[irq].chip->enable(irq);
 240
 241         return 0;
 242 }
 243
 244 /*
 245  * default shutdown function
 246  */
 247 static void default_shutdown(unsigned int irq)
 248 {
 249         struct irq_desc *desc = irq_desc + irq;
 250
 251         desc->chip->mask(irq);
 252         desc->status |= IRQ_MASKED;
 253 }
 254
 255 /*
 256  * Fixup enable/disable function pointers
 257  */
 258 void irq_chip_set_defaults(struct irq_chip *chip)
 259 {
 260         if (!chip->enable)
 261                 chip->enable = default_enable;
 262         if (!chip->disable)
 263                 chip->disable = default_disable;
 264         if (!chip->startup)
 265                 chip->startup = default_startup;
 266         /*
 267          * We use chip->disable, when the user provided its own. When
 268          * we have default_disable set for chip->disable, then we need
 269          * to use default_shutdown, otherwise the irq line is not
 270          * disabled on free_irq():
 271          */
 272         if (!chip->shutdown)
 273                 chip->shutdown = chip->disable != default_disable ?
 274                         chip->disable : default_shutdown;
 275         if (!chip->name)
 276                 chip->name = chip->typename;
 277         if (!chip->end)
 278                 chip->end = dummy_irq_chip.end;
 279 }
 280
 281 static inline void mask_ack_irq(struct irq_desc *desc, int irq)
 282 {
 283         if (desc->chip->mask_ack)
 284                 desc->chip->mask_ack(irq);
 285         else {
 286                 desc->chip->mask(irq);
 287                 desc->chip->ack(irq);
 288         }
 289 }
 290
 291 /**
 292  *      handle_simple_irq - Simple and software-decoded IRQs.
 293  *      @irq:   the interrupt number
 294  *      @desc:  the interrupt description structure for this irq
 295  *
 296  *      Simple interrupts are either sent from a demultiplexing interrupt
 297  *      handler or come from hardware, where no interrupt hardware control
 298  *      is necessary.
 299  *
 300  *      Note: The caller is expected to handle the ack, clear, mask and
 301  *      unmask issues if necessary.
 302  */
 303 void
 304 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
 305 {
 306         struct irqaction *action;
 307         irqreturn_t action_ret;
 308         const unsigned int cpu = smp_processor_id();
 309
 310         spin_lock(&desc->lock);
 311
 312         if (unlikely(desc->status & IRQ_INPROGRESS))
 313                 goto out_unlock;
 314         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 315         kstat_cpu(cpu).irqs[irq]++;
 316
 317         action = desc->action;
 318         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 319                 goto out_unlock;
 320
 321         desc->status |= IRQ_INPROGRESS;
 322         spin_unlock(&desc->lock);
 323
 324         action_ret = handle_IRQ_event(irq, action);
 325         if (!noirqdebug)
 326                 note_interrupt(irq, desc, action_ret);
 327
 328         spin_lock(&desc->lock);
 329         desc->status &= ~IRQ_INPROGRESS;
 330 out_unlock:
 331         spin_unlock(&desc->lock);
 332 }
 333
 334 /**
 335  *      handle_level_irq - Level type irq handler
 336  *      @irq:   the interrupt number
 337  *      @desc:  the interrupt description structure for this irq
 338  *
 339  *      Level type interrupts are active as long as the hardware line has
 340  *      the active level. This may require to mask the interrupt and unmask
 341  *      it after the associated handler has acknowledged the device, so the
 342  *      interrupt line is back to inactive.
 343  */
 344 void
 345 handle_level_irq(unsigned int irq, struct irq_desc *desc)
 346 {
 347         unsigned int cpu = smp_processor_id();
 348         struct irqaction *action;
 349         irqreturn_t action_ret;
 350
 351         spin_lock(&desc->lock);
 352         mask_ack_irq(desc, irq);
 353
 354         if (unlikely(desc->status & IRQ_INPROGRESS))
 355                 goto out_unlock;
 356         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 357         kstat_cpu(cpu).irqs[irq]++;
 358
 359         /*
 360          * If its disabled or no action available
 361          * keep it masked and get out of here
 362          */
 363         action = desc->action;
 364         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 365                 goto out_unlock;
 366
 367         desc->status |= IRQ_INPROGRESS;
 368         spin_unlock(&desc->lock);
 369
 370         action_ret = handle_IRQ_event(irq, action);
 371         if (!noirqdebug)
 372                 note_interrupt(irq, desc, action_ret);
 373
 374         spin_lock(&desc->lock);
 375         desc->status &= ~IRQ_INPROGRESS;
 376         if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
 377                 desc->chip->unmask(irq);
 378 out_unlock:
 379         spin_unlock(&desc->lock);
 380 }
 381
 382 /**
 383  *      handle_fasteoi_irq - irq handler for transparent controllers
 384  *      @irq:   the interrupt number
 385  *      @desc:  the interrupt description structure for this irq
 386  *
 387  *      Only a single callback will be issued to the chip: an ->eoi()
 388  *      call when the interrupt has been serviced. This enables support
 389  *      for modern forms of interrupt handlers, which handle the flow
 390  *      details in hardware, transparently.
 391  */
 392 void
 393 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 394 {
 395         unsigned int cpu = smp_processor_id();
 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_cpu(cpu).irqs[irq]++;
 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         const unsigned int cpu = smp_processor_id();
 455
 456         spin_lock(&desc->lock);
 457
 458         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 459
 460         /*
 461          * If we're currently running this IRQ, or its disabled,
 462          * we shouldn't process the IRQ. Mark it pending, handle
 463          * the necessary masking and go out
 464          */
 465         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 466                     !desc->action)) {
 467                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 468                 mask_ack_irq(desc, irq);
 469                 goto out_unlock;
 470         }
 471
 472         kstat_cpu(cpu).irqs[irq]++;
 473
 474         /* Start handling the irq */
 475         desc->chip->ack(irq);
 476
 477         /* Mark the IRQ currently in progress.*/
 478         desc->status |= IRQ_INPROGRESS;
 479
 480         do {
 481                 struct irqaction *action = desc->action;
 482                 irqreturn_t action_ret;
 483
 484                 if (unlikely(!action)) {
 485                         desc->chip->mask(irq);
 486                         goto out_unlock;
 487                 }
 488
 489                 /*
 490                  * When another irq arrived while we were handling
 491                  * one, we could have masked the irq.
 492                  * Renable it, if it was not disabled in meantime.
 493                  */
 494                 if (unlikely((desc->status &
 495                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 496                               (IRQ_PENDING | IRQ_MASKED))) {
 497                         desc->chip->unmask(irq);
 498                         desc->status &= ~IRQ_MASKED;
 499                 }
 500
 501                 desc->status &= ~IRQ_PENDING;
 502                 spin_unlock(&desc->lock);
 503                 action_ret = handle_IRQ_event(irq, action);
 504                 if (!noirqdebug)
 505                         note_interrupt(irq, desc, action_ret);
 506                 spin_lock(&desc->lock);
 507
 508         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 509
 510         desc->status &= ~IRQ_INPROGRESS;
 511 out_unlock:
 512         spin_unlock(&desc->lock);
 513 }
 514
 515 /**
 516  *      handle_percpu_IRQ - Per CPU local irq handler
 517  *      @irq:   the interrupt number
 518  *      @desc:  the interrupt description structure for this irq
 519  *
 520  *      Per CPU interrupts on SMP machines without locking requirements
 521  */
 522 void
 523 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
 524 {
 525         irqreturn_t action_ret;
 526
 527         kstat_this_cpu.irqs[irq]++;
 528
 529         if (desc->chip->ack)
 530                 desc->chip->ack(irq);
 531
 532         action_ret = handle_IRQ_event(irq, desc->action);
 533         if (!noirqdebug)
 534                 note_interrupt(irq, desc, action_ret);
 535
 536         if (desc->chip->eoi)
 537                 desc->chip->eoi(irq);
 538 }
 539
 540 void
 541 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
 542                   const char *name)
 543 {
 544         struct irq_desc *desc;
 545         unsigned long flags;
 546
 547         if (irq >= NR_IRQS) {
 548                 printk(KERN_ERR
 549                        "Trying to install type control for IRQ%d\n", irq);
 550                 return;
 551         }
 552
 553         desc = irq_desc + irq;
 554
 555         if (!handle)
 556                 handle = handle_bad_irq;
 557         else if (desc->chip == &no_irq_chip) {
 558                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 559                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
 560                 /*
 561                  * Some ARM implementations install a handler for really dumb
 562                  * interrupt hardware without setting an irq_chip. This worked
 563                  * with the ARM no_irq_chip but the check in setup_irq would
 564                  * prevent us to setup the interrupt at all. Switch it to
 565                  * dummy_irq_chip for easy transition.
 566                  */
 567                 desc->chip = &dummy_irq_chip;
 568         }
 569
 570         spin_lock_irqsave(&desc->lock, flags);
 571
 572         /* Uninstall? */
 573         if (handle == handle_bad_irq) {
 574                 if (desc->chip != &no_irq_chip)
 575                         mask_ack_irq(desc, irq);
 576                 desc->status |= IRQ_DISABLED;
 577                 desc->depth = 1;
 578         }
 579         desc->handle_irq = handle;
 580         desc->name = name;
 581
 582         if (handle != handle_bad_irq && is_chained) {
 583                 desc->status &= ~IRQ_DISABLED;
 584                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 585                 desc->depth = 0;
 586                 desc->chip->unmask(irq);
 587         }
 588         spin_unlock_irqrestore(&desc->lock, flags);
 589 }
 590
 591 void
 592 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 593                          irq_flow_handler_t handle)
 594 {
 595         set_irq_chip(irq, chip);
 596         __set_irq_handler(irq, handle, 0, NULL);
 597 }
 598
 599 void
 600 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
 601                               irq_flow_handler_t handle, const char *name)
 602 {
 603         set_irq_chip(irq, chip);
 604         __set_irq_handler(irq, handle, 0, name);
 605 }
 606
 607 void __init set_irq_noprobe(unsigned int irq)
 608 {
 609         struct irq_desc *desc;
 610         unsigned long flags;
 611
 612         if (irq >= NR_IRQS) {
 613                 printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);
 614
 615                 return;
 616         }
 617
 618         desc = irq_desc + irq;
 619
 620         spin_lock_irqsave(&desc->lock, flags);
 621         desc->status |= IRQ_NOPROBE;
 622         spin_unlock_irqrestore(&desc->lock, flags);
 623 }
 624
 625 void __init set_irq_probe(unsigned int irq)
 626 {
 627         struct irq_desc *desc;
 628         unsigned long flags;
 629
 630         if (irq >= NR_IRQS) {
 631                 printk(KERN_ERR "Trying to mark IRQ%d probeable\n", irq);
 632
 633                 return;
 634         }
 635
 636         desc = irq_desc + irq;
 637
 638         spin_lock_irqsave(&desc->lock, flags);
 639         desc->status &= ~IRQ_NOPROBE;
 640         spin_unlock_irqrestore(&desc->lock, flags);
 641 }