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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 #ifdef CONFIG_GENERIC_PENDING_IRQ
  51         cpumask_clear(desc->pending_mask);
  52 #endif
  53 #endif
  54         spin_unlock_irqrestore(&desc->lock, flags);
  55 }
  56
  57 /**
  58  *      dynamic_irq_cleanup - cleanup a dynamically allocated irq
  59  *      @irq:   irq number to initialize
  60  */
  61 void dynamic_irq_cleanup(unsigned int irq)
  62 {
  63         struct irq_desc *desc = irq_to_desc(irq);
  64         unsigned long flags;
  65
  66         if (!desc) {
  67                 WARN(1, KERN_ERR "Trying to cleanup invalid IRQ%d\n", irq);
  68                 return;
  69         }
  70
  71         spin_lock_irqsave(&desc->lock, flags);
  72         if (desc->action) {
  73                 spin_unlock_irqrestore(&desc->lock, flags);
  74                 WARN(1, KERN_ERR "Destroying IRQ%d without calling free_irq\n",
  75                         irq);
  76                 return;
  77         }
  78         desc->msi_desc = NULL;
  79         desc->handler_data = NULL;
  80         desc->chip_data = NULL;
  81         desc->handle_irq = handle_bad_irq;
  82         desc->chip = &no_irq_chip;
  83         desc->name = NULL;
  84         spin_unlock_irqrestore(&desc->lock, flags);
  85 }
  86
  87
  88 /**
  89  *      set_irq_chip - set the irq chip for an irq
  90  *      @irq:   irq number
  91  *      @chip:  pointer to irq chip description structure
  92  */
  93 int set_irq_chip(unsigned int irq, struct irq_chip *chip)
  94 {
  95         struct irq_desc *desc = irq_to_desc(irq);
  96         unsigned long flags;
  97
  98         if (!desc) {
  99                 WARN(1, KERN_ERR "Trying to install chip for IRQ%d\n", irq);
 100                 return -EINVAL;
 101         }
 102
 103         if (!chip)
 104                 chip = &no_irq_chip;
 105
 106         spin_lock_irqsave(&desc->lock, flags);
 107         irq_chip_set_defaults(chip);
 108         desc->chip = chip;
 109         spin_unlock_irqrestore(&desc->lock, flags);
 110
 111         return 0;
 112 }
 113 EXPORT_SYMBOL(set_irq_chip);
 114
 115 /**
 116  *      set_irq_type - set the irq trigger type for an irq
 117  *      @irq:   irq number
 118  *      @type:  IRQ_TYPE_{LEVEL,EDGE}_* value - see include/linux/irq.h
 119  */
 120 int set_irq_type(unsigned int irq, unsigned int type)
 121 {
 122         struct irq_desc *desc = irq_to_desc(irq);
 123         unsigned long flags;
 124         int ret = -ENXIO;
 125
 126         if (!desc) {
 127                 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
 128                 return -ENODEV;
 129         }
 130
 131         type &= IRQ_TYPE_SENSE_MASK;
 132         if (type == IRQ_TYPE_NONE)
 133                 return 0;
 134
 135         spin_lock_irqsave(&desc->lock, flags);
 136         ret = __irq_set_trigger(desc, irq, type);
 137         spin_unlock_irqrestore(&desc->lock, flags);
 138         return ret;
 139 }
 140 EXPORT_SYMBOL(set_irq_type);
 141
 142 /**
 143  *      set_irq_data - set irq type data for an irq
 144  *      @irq:   Interrupt number
 145  *      @data:  Pointer to interrupt specific data
 146  *
 147  *      Set the hardware irq controller data for an irq
 148  */
 149 int set_irq_data(unsigned int irq, void *data)
 150 {
 151         struct irq_desc *desc = irq_to_desc(irq);
 152         unsigned long flags;
 153
 154         if (!desc) {
 155                 printk(KERN_ERR
 156                        "Trying to install controller data for IRQ%d\n", irq);
 157                 return -EINVAL;
 158         }
 159
 160         spin_lock_irqsave(&desc->lock, flags);
 161         desc->handler_data = data;
 162         spin_unlock_irqrestore(&desc->lock, flags);
 163         return 0;
 164 }
 165 EXPORT_SYMBOL(set_irq_data);
 166
 167 /**
 168  *      set_irq_data - set irq type data for an irq
 169  *      @irq:   Interrupt number
 170  *      @entry: Pointer to MSI descriptor data
 171  *
 172  *      Set the hardware irq controller data for an irq
 173  */
 174 int set_irq_msi(unsigned int irq, struct msi_desc *entry)
 175 {
 176         struct irq_desc *desc = irq_to_desc(irq);
 177         unsigned long flags;
 178
 179         if (!desc) {
 180                 printk(KERN_ERR
 181                        "Trying to install msi data for IRQ%d\n", irq);
 182                 return -EINVAL;
 183         }
 184
 185         spin_lock_irqsave(&desc->lock, flags);
 186         desc->msi_desc = entry;
 187         if (entry)
 188                 entry->irq = irq;
 189         spin_unlock_irqrestore(&desc->lock, flags);
 190         return 0;
 191 }
 192
 193 /**
 194  *      set_irq_chip_data - set irq chip data for an irq
 195  *      @irq:   Interrupt number
 196  *      @data:  Pointer to chip specific data
 197  *
 198  *      Set the hardware irq chip data for an irq
 199  */
 200 int set_irq_chip_data(unsigned int irq, void *data)
 201 {
 202         struct irq_desc *desc = irq_to_desc(irq);
 203         unsigned long flags;
 204
 205         if (!desc) {
 206                 printk(KERN_ERR
 207                        "Trying to install chip data for IRQ%d\n", irq);
 208                 return -EINVAL;
 209         }
 210
 211         if (!desc->chip) {
 212                 printk(KERN_ERR "BUG: bad set_irq_chip_data(IRQ#%d)\n", irq);
 213                 return -EINVAL;
 214         }
 215
 216         spin_lock_irqsave(&desc->lock, flags);
 217         desc->chip_data = data;
 218         spin_unlock_irqrestore(&desc->lock, flags);
 219
 220         return 0;
 221 }
 222 EXPORT_SYMBOL(set_irq_chip_data);
 223
 224 /*
 225  * default enable function
 226  */
 227 static void default_enable(unsigned int irq)
 228 {
 229         struct irq_desc *desc = irq_to_desc(irq);
 230
 231         desc->chip->unmask(irq);
 232         desc->status &= ~IRQ_MASKED;
 233 }
 234
 235 /*
 236  * default disable function
 237  */
 238 static void default_disable(unsigned int irq)
 239 {
 240 }
 241
 242 /*
 243  * default startup function
 244  */
 245 static unsigned int default_startup(unsigned int irq)
 246 {
 247         struct irq_desc *desc = irq_to_desc(irq);
 248
 249         desc->chip->enable(irq);
 250         return 0;
 251 }
 252
 253 /*
 254  * default shutdown function
 255  */
 256 static void default_shutdown(unsigned int irq)
 257 {
 258         struct irq_desc *desc = irq_to_desc(irq);
 259
 260         desc->chip->mask(irq);
 261         desc->status |= IRQ_MASKED;
 262 }
 263
 264 /*
 265  * Fixup enable/disable function pointers
 266  */
 267 void irq_chip_set_defaults(struct irq_chip *chip)
 268 {
 269         if (!chip->enable)
 270                 chip->enable = default_enable;
 271         if (!chip->disable)
 272                 chip->disable = default_disable;
 273         if (!chip->startup)
 274                 chip->startup = default_startup;
 275         /*
 276          * We use chip->disable, when the user provided its own. When
 277          * we have default_disable set for chip->disable, then we need
 278          * to use default_shutdown, otherwise the irq line is not
 279          * disabled on free_irq():
 280          */
 281         if (!chip->shutdown)
 282                 chip->shutdown = chip->disable != default_disable ?
 283                         chip->disable : default_shutdown;
 284         if (!chip->name)
 285                 chip->name = chip->typename;
 286         if (!chip->end)
 287                 chip->end = dummy_irq_chip.end;
 288 }
 289
 290 static inline void mask_ack_irq(struct irq_desc *desc, int irq)
 291 {
 292         if (desc->chip->mask_ack)
 293                 desc->chip->mask_ack(irq);
 294         else {
 295                 desc->chip->mask(irq);
 296                 desc->chip->ack(irq);
 297         }
 298 }
 299
 300 /**
 301  *      handle_simple_irq - Simple and software-decoded IRQs.
 302  *      @irq:   the interrupt number
 303  *      @desc:  the interrupt description structure for this irq
 304  *
 305  *      Simple interrupts are either sent from a demultiplexing interrupt
 306  *      handler or come from hardware, where no interrupt hardware control
 307  *      is necessary.
 308  *
 309  *      Note: The caller is expected to handle the ack, clear, mask and
 310  *      unmask issues if necessary.
 311  */
 312 void
 313 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
 314 {
 315         struct irqaction *action;
 316         irqreturn_t action_ret;
 317
 318         spin_lock(&desc->lock);
 319
 320         if (unlikely(desc->status & IRQ_INPROGRESS))
 321                 goto out_unlock;
 322         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 323         kstat_incr_irqs_this_cpu(irq, desc);
 324
 325         action = desc->action;
 326         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 327                 goto out_unlock;
 328
 329         desc->status |= IRQ_INPROGRESS;
 330         spin_unlock(&desc->lock);
 331
 332         action_ret = handle_IRQ_event(irq, action);
 333         if (!noirqdebug)
 334                 note_interrupt(irq, desc, action_ret);
 335
 336         spin_lock(&desc->lock);
 337         desc->status &= ~IRQ_INPROGRESS;
 338 out_unlock:
 339         spin_unlock(&desc->lock);
 340 }
 341
 342 /**
 343  *      handle_level_irq - Level type irq handler
 344  *      @irq:   the interrupt number
 345  *      @desc:  the interrupt description structure for this irq
 346  *
 347  *      Level type interrupts are active as long as the hardware line has
 348  *      the active level. This may require to mask the interrupt and unmask
 349  *      it after the associated handler has acknowledged the device, so the
 350  *      interrupt line is back to inactive.
 351  */
 352 void
 353 handle_level_irq(unsigned int irq, struct irq_desc *desc)
 354 {
 355         struct irqaction *action;
 356         irqreturn_t action_ret;
 357
 358         spin_lock(&desc->lock);
 359         mask_ack_irq(desc, irq);
 360         desc = irq_remap_to_desc(irq, desc);
 361
 362         if (unlikely(desc->status & IRQ_INPROGRESS))
 363                 goto out_unlock;
 364         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 365         kstat_incr_irqs_this_cpu(irq, desc);
 366
 367         /*
 368          * If its disabled or no action available
 369          * keep it masked and get out of here
 370          */
 371         action = desc->action;
 372         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 373                 goto out_unlock;
 374
 375         desc->status |= IRQ_INPROGRESS;
 376         spin_unlock(&desc->lock);
 377
 378         action_ret = handle_IRQ_event(irq, action);
 379         if (!noirqdebug)
 380                 note_interrupt(irq, desc, action_ret);
 381
 382         spin_lock(&desc->lock);
 383         desc->status &= ~IRQ_INPROGRESS;
 384         if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
 385                 desc->chip->unmask(irq);
 386 out_unlock:
 387         spin_unlock(&desc->lock);
 388 }
 389
 390 /**
 391  *      handle_fasteoi_irq - irq handler for transparent controllers
 392  *      @irq:   the interrupt number
 393  *      @desc:  the interrupt description structure for this irq
 394  *
 395  *      Only a single callback will be issued to the chip: an ->eoi()
 396  *      call when the interrupt has been serviced. This enables support
 397  *      for modern forms of interrupt handlers, which handle the flow
 398  *      details in hardware, transparently.
 399  */
 400 void
 401 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 402 {
 403         struct irqaction *action;
 404         irqreturn_t action_ret;
 405
 406         spin_lock(&desc->lock);
 407
 408         if (unlikely(desc->status & IRQ_INPROGRESS))
 409                 goto out;
 410
 411         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 412         kstat_incr_irqs_this_cpu(irq, desc);
 413
 414         /*
 415          * If its disabled or no action available
 416          * then mask it and get out of here:
 417          */
 418         action = desc->action;
 419         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 420                 desc->status |= IRQ_PENDING;
 421                 if (desc->chip->mask)
 422                         desc->chip->mask(irq);
 423                 goto out;
 424         }
 425
 426         desc->status |= IRQ_INPROGRESS;
 427         desc->status &= ~IRQ_PENDING;
 428         spin_unlock(&desc->lock);
 429
 430         action_ret = handle_IRQ_event(irq, action);
 431         if (!noirqdebug)
 432                 note_interrupt(irq, desc, action_ret);
 433
 434         spin_lock(&desc->lock);
 435         desc->status &= ~IRQ_INPROGRESS;
 436 out:
 437         desc->chip->eoi(irq);
 438         desc = irq_remap_to_desc(irq, desc);
 439
 440         spin_unlock(&desc->lock);
 441 }
 442
 443 /**
 444  *      handle_edge_irq - edge type IRQ handler
 445  *      @irq:   the interrupt number
 446  *      @desc:  the interrupt description structure for this irq
 447  *
 448  *      Interrupt occures on the falling and/or rising edge of a hardware
 449  *      signal. The occurence is latched into the irq controller hardware
 450  *      and must be acked in order to be reenabled. After the ack another
 451  *      interrupt can happen on the same source even before the first one
 452  *      is handled by the assosiacted event handler. If this happens it
 453  *      might be necessary to disable (mask) the interrupt depending on the
 454  *      controller hardware. This requires to reenable the interrupt inside
 455  *      of the loop which handles the interrupts which have arrived while
 456  *      the handler was running. If all pending interrupts are handled, the
 457  *      loop is left.
 458  */
 459 void
 460 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
 461 {
 462         spin_lock(&desc->lock);
 463
 464         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 465
 466         /*
 467          * If we're currently running this IRQ, or its disabled,
 468          * we shouldn't process the IRQ. Mark it pending, handle
 469          * the necessary masking and go out
 470          */
 471         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 472                     !desc->action)) {
 473                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 474                 mask_ack_irq(desc, irq);
 475                 desc = irq_remap_to_desc(irq, desc);
 476                 goto out_unlock;
 477         }
 478         kstat_incr_irqs_this_cpu(irq, desc);
 479
 480         /* Start handling the irq */
 481         desc->chip->ack(irq);
 482         desc = irq_remap_to_desc(irq, desc);
 483
 484         /* Mark the IRQ currently in progress.*/
 485         desc->status |= IRQ_INPROGRESS;
 486
 487         do {
 488                 struct irqaction *action = desc->action;
 489                 irqreturn_t action_ret;
 490
 491                 if (unlikely(!action)) {
 492                         desc->chip->mask(irq);
 493                         goto out_unlock;
 494                 }
 495
 496                 /*
 497                  * When another irq arrived while we were handling
 498                  * one, we could have masked the irq.
 499                  * Renable it, if it was not disabled in meantime.
 500                  */
 501                 if (unlikely((desc->status &
 502                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 503                               (IRQ_PENDING | IRQ_MASKED))) {
 504                         desc->chip->unmask(irq);
 505                         desc->status &= ~IRQ_MASKED;
 506                 }
 507
 508                 desc->status &= ~IRQ_PENDING;
 509                 spin_unlock(&desc->lock);
 510                 action_ret = handle_IRQ_event(irq, action);
 511                 if (!noirqdebug)
 512                         note_interrupt(irq, desc, action_ret);
 513                 spin_lock(&desc->lock);
 514
 515         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 516
 517         desc->status &= ~IRQ_INPROGRESS;
 518 out_unlock:
 519         spin_unlock(&desc->lock);
 520 }
 521
 522 /**
 523  *      handle_percpu_IRQ - Per CPU local irq handler
 524  *      @irq:   the interrupt number
 525  *      @desc:  the interrupt description structure for this irq
 526  *
 527  *      Per CPU interrupts on SMP machines without locking requirements
 528  */
 529 void
 530 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
 531 {
 532         irqreturn_t action_ret;
 533
 534         kstat_incr_irqs_this_cpu(irq, desc);
 535
 536         if (desc->chip->ack)
 537                 desc->chip->ack(irq);
 538
 539         action_ret = handle_IRQ_event(irq, desc->action);
 540         if (!noirqdebug)
 541                 note_interrupt(irq, desc, action_ret);
 542
 543         if (desc->chip->eoi) {
 544                 desc->chip->eoi(irq);
 545                 desc = irq_remap_to_desc(irq, desc);
 546         }
 547 }
 548
 549 void
 550 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
 551                   const char *name)
 552 {
 553         struct irq_desc *desc = irq_to_desc(irq);
 554         unsigned long flags;
 555
 556         if (!desc) {
 557                 printk(KERN_ERR
 558                        "Trying to install type control for IRQ%d\n", irq);
 559                 return;
 560         }
 561
 562         if (!handle)
 563                 handle = handle_bad_irq;
 564         else if (desc->chip == &no_irq_chip) {
 565                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 566                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
 567                 /*
 568                  * Some ARM implementations install a handler for really dumb
 569                  * interrupt hardware without setting an irq_chip. This worked
 570                  * with the ARM no_irq_chip but the check in setup_irq would
 571                  * prevent us to setup the interrupt at all. Switch it to
 572                  * dummy_irq_chip for easy transition.
 573                  */
 574                 desc->chip = &dummy_irq_chip;
 575         }
 576
 577         spin_lock_irqsave(&desc->lock, flags);
 578
 579         /* Uninstall? */
 580         if (handle == handle_bad_irq) {
 581                 if (desc->chip != &no_irq_chip) {
 582                         mask_ack_irq(desc, irq);
 583                         desc = irq_remap_to_desc(irq, desc);
 584                 }
 585                 desc->status |= IRQ_DISABLED;
 586                 desc->depth = 1;
 587         }
 588         desc->handle_irq = handle;
 589         desc->name = name;
 590
 591         if (handle != handle_bad_irq && is_chained) {
 592                 desc->status &= ~IRQ_DISABLED;
 593                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 594                 desc->depth = 0;
 595                 desc->chip->startup(irq);
 596         }
 597         spin_unlock_irqrestore(&desc->lock, flags);
 598 }
 599
 600 void
 601 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 602                          irq_flow_handler_t handle)
 603 {
 604         set_irq_chip(irq, chip);
 605         __set_irq_handler(irq, handle, 0, NULL);
 606 }
 607
 608 void
 609 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
 610                               irq_flow_handler_t handle, const char *name)
 611 {
 612         set_irq_chip(irq, chip);
 613         __set_irq_handler(irq, handle, 0, name);
 614 }
 615
 616 void __init set_irq_noprobe(unsigned int irq)
 617 {
 618         struct irq_desc *desc = irq_to_desc(irq);
 619         unsigned long flags;
 620
 621         if (!desc) {
 622                 printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);
 623                 return;
 624         }
 625
 626         spin_lock_irqsave(&desc->lock, flags);
 627         desc->status |= IRQ_NOPROBE;
 628         spin_unlock_irqrestore(&desc->lock, flags);
 629 }
 630
 631 void __init set_irq_probe(unsigned int irq)
 632 {
 633         struct irq_desc *desc = irq_to_desc(irq);
 634         unsigned long flags;
 635
 636         if (!desc) {
 637                 printk(KERN_ERR "Trying to mark IRQ%d probeable\n", irq);
 638                 return;
 639         }
 640
 641         spin_lock_irqsave(&desc->lock, flags);
 642         desc->status &= ~IRQ_NOPROBE;
 643         spin_unlock_irqrestore(&desc->lock, flags);
 644 }