kernel/irq/chip.c

   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         /* first time to use this irq_desc */
  31         desc = irq_to_desc_alloc(irq);
  32         if (!desc) {
  33                 WARN(1, KERN_ERR "Trying to initialize invalid IRQ%d\n", irq);
  34                 return;
  35         }
  36
  37         /* Ensure we don't have left over values from a previous use of this irq */
  38         spin_lock_irqsave(&desc->lock, flags);
  39         desc->status = IRQ_DISABLED;
  40         desc->chip = &no_irq_chip;
  41         desc->handle_irq = handle_bad_irq;
  42         desc->depth = 1;
  43         desc->msi_desc = NULL;
  44         desc->handler_data = NULL;
  45         desc->chip_data = NULL;
  46         desc->action = NULL;
  47         desc->irq_count = 0;
  48         desc->irqs_unhandled = 0;
  49 #ifdef CONFIG_SMP
  50         cpus_setall(desc->affinity);
  51 #endif
  52         spin_unlock_irqrestore(&desc->lock, flags);
  53 }
  54
  55 /**
  56  *      dynamic_irq_cleanup - cleanup a dynamically allocated irq
  57  *      @irq:   irq number to initialize
  58  */
  59 void dynamic_irq_cleanup(unsigned int irq)
  60 {
  61         struct irq_desc *desc;
  62         unsigned long flags;
  63
  64         desc = irq_to_desc(irq);
  65         if (!desc) {
  66                 WARN(1, KERN_ERR "Trying to cleanup invalid IRQ%d\n", irq);
  67                 return;
  68         }
  69
  70         spin_lock_irqsave(&desc->lock, flags);
  71         if (desc->action) {
  72                 spin_unlock_irqrestore(&desc->lock, flags);
  73                 WARN(1, KERN_ERR "Destroying IRQ%d without calling free_irq\n",
  74                         irq);
  75                 return;
  76         }
  77         desc->msi_desc = NULL;
  78         desc->handler_data = NULL;
  79         desc->chip_data = NULL;
  80         desc->handle_irq = handle_bad_irq;
  81         desc->chip = &no_irq_chip;
  82         spin_unlock_irqrestore(&desc->lock, flags);
  83 }
  84
  85
  86 /**
  87  *      set_irq_chip - set the irq chip for an irq
  88  *      @irq:   irq number
  89  *      @chip:  pointer to irq chip description structure
  90  */
  91 int set_irq_chip(unsigned int irq, struct irq_chip *chip)
  92 {
  93         struct irq_desc *desc;
  94         unsigned long flags;
  95
  96         desc = irq_to_desc(irq);
  97         if (!desc) {
  98                 WARN(1, KERN_ERR "Trying to install chip for IRQ%d\n", irq);
  99                 return -EINVAL;
 100         }
 101
 102         if (!chip)
 103                 chip = &no_irq_chip;
 104
 105         desc = irq_to_desc(irq);
 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;
 123         unsigned long flags;
 124         int ret = -ENXIO;
 125
 126         desc = irq_to_desc(irq);
 127         if (!desc) {
 128                 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
 129                 return -ENODEV;
 130         }
 131
 132         if (type == IRQ_TYPE_NONE)
 133                 return 0;
 134
 135         spin_lock_irqsave(&desc->lock, flags);
 136         ret = __irq_set_trigger(desc, irq, flags);
 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;
 152         unsigned long flags;
 153
 154         desc = irq_to_desc(irq);
 155         if (!desc) {
 156                 printk(KERN_ERR
 157                        "Trying to install controller data for IRQ%d\n", irq);
 158                 return -EINVAL;
 159         }
 160
 161         spin_lock_irqsave(&desc->lock, flags);
 162         desc->handler_data = data;
 163         spin_unlock_irqrestore(&desc->lock, flags);
 164         return 0;
 165 }
 166 EXPORT_SYMBOL(set_irq_data);
 167
 168 /**
 169  *      set_irq_data - set irq type data for an irq
 170  *      @irq:   Interrupt number
 171  *      @entry: Pointer to MSI descriptor data
 172  *
 173  *      Set the hardware irq controller data for an irq
 174  */
 175 int set_irq_msi(unsigned int irq, struct msi_desc *entry)
 176 {
 177         struct irq_desc *desc;
 178         unsigned long flags;
 179
 180         desc = irq_to_desc(irq);
 181         if (!desc) {
 182                 printk(KERN_ERR
 183                        "Trying to install msi data for IRQ%d\n", irq);
 184                 return -EINVAL;
 185         }
 186
 187         spin_lock_irqsave(&desc->lock, flags);
 188         desc->msi_desc = entry;
 189         if (entry)
 190                 entry->irq = irq;
 191         spin_unlock_irqrestore(&desc->lock, flags);
 192         return 0;
 193 }
 194
 195 /**
 196  *      set_irq_chip_data - set irq chip data for an irq
 197  *      @irq:   Interrupt number
 198  *      @data:  Pointer to chip specific data
 199  *
 200  *      Set the hardware irq chip data for an irq
 201  */
 202 int set_irq_chip_data(unsigned int irq, void *data)
 203 {
 204         struct irq_desc *desc;
 205         unsigned long flags;
 206
 207         desc = irq_to_desc(irq);
 208         if (!desc) {
 209                 printk(KERN_ERR
 210                        "Trying to install chip data for IRQ%d\n", irq);
 211                 return -EINVAL;
 212         }
 213
 214         if (!desc->chip) {
 215                 printk(KERN_ERR "BUG: bad set_irq_chip_data(IRQ#%d)\n", irq);
 216                 return -EINVAL;
 217         }
 218
 219         spin_lock_irqsave(&desc->lock, flags);
 220         desc->chip_data = data;
 221         spin_unlock_irqrestore(&desc->lock, flags);
 222
 223         return 0;
 224 }
 225 EXPORT_SYMBOL(set_irq_chip_data);
 226
 227 /*
 228  * default enable function
 229  */
 230 static void default_enable(unsigned int irq)
 231 {
 232         struct irq_desc *desc;
 233
 234         desc = irq_to_desc(irq);
 235         desc->chip->unmask(irq);
 236         desc->status &= ~IRQ_MASKED;
 237 }
 238
 239 /*
 240  * default disable function
 241  */
 242 static void default_disable(unsigned int irq)
 243 {
 244 }
 245
 246 /*
 247  * default startup function
 248  */
 249 static unsigned int default_startup(unsigned int irq)
 250 {
 251         struct irq_desc *desc;
 252
 253         desc = irq_to_desc(irq);
 254         desc->chip->enable(irq);
 255
 256         return 0;
 257 }
 258
 259 /*
 260  * default shutdown function
 261  */
 262 static void default_shutdown(unsigned int irq)
 263 {
 264         struct irq_desc *desc;
 265
 266         desc = irq_to_desc(irq);
 267         desc->chip->mask(irq);
 268         desc->status |= IRQ_MASKED;
 269 }
 270
 271 /*
 272  * Fixup enable/disable function pointers
 273  */
 274 void irq_chip_set_defaults(struct irq_chip *chip)
 275 {
 276         if (!chip->enable)
 277                 chip->enable = default_enable;
 278         if (!chip->disable)
 279                 chip->disable = default_disable;
 280         if (!chip->startup)
 281                 chip->startup = default_startup;
 282         /*
 283          * We use chip->disable, when the user provided its own. When
 284          * we have default_disable set for chip->disable, then we need
 285          * to use default_shutdown, otherwise the irq line is not
 286          * disabled on free_irq():
 287          */
 288         if (!chip->shutdown)
 289                 chip->shutdown = chip->disable != default_disable ?
 290                         chip->disable : default_shutdown;
 291         if (!chip->name)
 292                 chip->name = chip->typename;
 293         if (!chip->end)
 294                 chip->end = dummy_irq_chip.end;
 295 }
 296
 297 static inline void mask_ack_irq(struct irq_desc *desc, int irq)
 298 {
 299         if (desc->chip->mask_ack)
 300                 desc->chip->mask_ack(irq);
 301         else {
 302                 desc->chip->mask(irq);
 303                 desc->chip->ack(irq);
 304         }
 305 }
 306
 307 /**
 308  *      handle_simple_irq - Simple and software-decoded IRQs.
 309  *      @irq:   the interrupt number
 310  *      @desc:  the interrupt description structure for this irq
 311  *
 312  *      Simple interrupts are either sent from a demultiplexing interrupt
 313  *      handler or come from hardware, where no interrupt hardware control
 314  *      is necessary.
 315  *
 316  *      Note: The caller is expected to handle the ack, clear, mask and
 317  *      unmask issues if necessary.
 318  */
 319 void
 320 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
 321 {
 322         struct irqaction *action;
 323         irqreturn_t action_ret;
 324
 325         spin_lock(&desc->lock);
 326
 327         if (unlikely(desc->status & IRQ_INPROGRESS))
 328                 goto out_unlock;
 329         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 330         kstat_irqs_this_cpu(desc)++;
 331
 332         action = desc->action;
 333         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 334                 goto out_unlock;
 335
 336         desc->status |= IRQ_INPROGRESS;
 337         spin_unlock(&desc->lock);
 338
 339         action_ret = handle_IRQ_event(irq, action);
 340         if (!noirqdebug)
 341                 note_interrupt(irq, desc, action_ret);
 342
 343         spin_lock(&desc->lock);
 344         desc->status &= ~IRQ_INPROGRESS;
 345 out_unlock:
 346         spin_unlock(&desc->lock);
 347 }
 348
 349 /**
 350  *      handle_level_irq - Level type irq handler
 351  *      @irq:   the interrupt number
 352  *      @desc:  the interrupt description structure for this irq
 353  *
 354  *      Level type interrupts are active as long as the hardware line has
 355  *      the active level. This may require to mask the interrupt and unmask
 356  *      it after the associated handler has acknowledged the device, so the
 357  *      interrupt line is back to inactive.
 358  */
 359 void
 360 handle_level_irq(unsigned int irq, struct irq_desc *desc)
 361 {
 362         struct irqaction *action;
 363         irqreturn_t action_ret;
 364
 365         spin_lock(&desc->lock);
 366         mask_ack_irq(desc, irq);
 367
 368         if (unlikely(desc->status & IRQ_INPROGRESS))
 369                 goto out_unlock;
 370         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 371         kstat_irqs_this_cpu(desc)++;
 372
 373         /*
 374          * If its disabled or no action available
 375          * keep it masked and get out of here
 376          */
 377         action = desc->action;
 378         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 379                 goto out_unlock;
 380
 381         desc->status |= IRQ_INPROGRESS;
 382         spin_unlock(&desc->lock);
 383
 384         action_ret = handle_IRQ_event(irq, action);
 385         if (!noirqdebug)
 386                 note_interrupt(irq, desc, action_ret);
 387
 388         spin_lock(&desc->lock);
 389         desc->status &= ~IRQ_INPROGRESS;
 390         if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
 391                 desc->chip->unmask(irq);
 392 out_unlock:
 393         spin_unlock(&desc->lock);
 394 }
 395
 396 /**
 397  *      handle_fasteoi_irq - irq handler for transparent controllers
 398  *      @irq:   the interrupt number
 399  *      @desc:  the interrupt description structure for this irq
 400  *
 401  *      Only a single callback will be issued to the chip: an ->eoi()
 402  *      call when the interrupt has been serviced. This enables support
 403  *      for modern forms of interrupt handlers, which handle the flow
 404  *      details in hardware, transparently.
 405  */
 406 void
 407 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 408 {
 409         struct irqaction *action;
 410         irqreturn_t action_ret;
 411
 412         spin_lock(&desc->lock);
 413
 414         if (unlikely(desc->status & IRQ_INPROGRESS))
 415                 goto out;
 416
 417         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 418         kstat_irqs_this_cpu(desc)++;
 419
 420         /*
 421          * If its disabled or no action available
 422          * then mask it and get out of here:
 423          */
 424         action = desc->action;
 425         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 426                 desc->status |= IRQ_PENDING;
 427                 if (desc->chip->mask)
 428                         desc->chip->mask(irq);
 429                 goto out;
 430         }
 431
 432         desc->status |= IRQ_INPROGRESS;
 433         desc->status &= ~IRQ_PENDING;
 434         spin_unlock(&desc->lock);
 435
 436         action_ret = handle_IRQ_event(irq, action);
 437         if (!noirqdebug)
 438                 note_interrupt(irq, desc, action_ret);
 439
 440         spin_lock(&desc->lock);
 441         desc->status &= ~IRQ_INPROGRESS;
 442 out:
 443         desc->chip->eoi(irq);
 444
 445         spin_unlock(&desc->lock);
 446 }
 447
 448 /**
 449  *      handle_edge_irq - edge type IRQ handler
 450  *      @irq:   the interrupt number
 451  *      @desc:  the interrupt description structure for this irq
 452  *
 453  *      Interrupt occures on the falling and/or rising edge of a hardware
 454  *      signal. The occurence is latched into the irq controller hardware
 455  *      and must be acked in order to be reenabled. After the ack another
 456  *      interrupt can happen on the same source even before the first one
 457  *      is handled by the assosiacted event handler. If this happens it
 458  *      might be necessary to disable (mask) the interrupt depending on the
 459  *      controller hardware. This requires to reenable the interrupt inside
 460  *      of the loop which handles the interrupts which have arrived while
 461  *      the handler was running. If all pending interrupts are handled, the
 462  *      loop is left.
 463  */
 464 void
 465 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
 466 {
 467         spin_lock(&desc->lock);
 468
 469         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 470
 471         /*
 472          * If we're currently running this IRQ, or its disabled,
 473          * we shouldn't process the IRQ. Mark it pending, handle
 474          * the necessary masking and go out
 475          */
 476         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 477                     !desc->action)) {
 478                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 479                 mask_ack_irq(desc, irq);
 480                 goto out_unlock;
 481         }
 482
 483         kstat_irqs_this_cpu(desc)++;
 484
 485         /* Start handling the irq */
 486         desc->chip->ack(irq);
 487
 488         /* Mark the IRQ currently in progress.*/
 489         desc->status |= IRQ_INPROGRESS;
 490
 491         do {
 492                 struct irqaction *action = desc->action;
 493                 irqreturn_t action_ret;
 494
 495                 if (unlikely(!action)) {
 496                         desc->chip->mask(irq);
 497                         goto out_unlock;
 498                 }
 499
 500                 /*
 501                  * When another irq arrived while we were handling
 502                  * one, we could have masked the irq.
 503                  * Renable it, if it was not disabled in meantime.
 504                  */
 505                 if (unlikely((desc->status &
 506                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 507                               (IRQ_PENDING | IRQ_MASKED))) {
 508                         desc->chip->unmask(irq);
 509                         desc->status &= ~IRQ_MASKED;
 510                 }
 511
 512                 desc->status &= ~IRQ_PENDING;
 513                 spin_unlock(&desc->lock);
 514                 action_ret = handle_IRQ_event(irq, action);
 515                 if (!noirqdebug)
 516                         note_interrupt(irq, desc, action_ret);
 517                 spin_lock(&desc->lock);
 518
 519         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 520
 521         desc->status &= ~IRQ_INPROGRESS;
 522 out_unlock:
 523         spin_unlock(&desc->lock);
 524 }
 525
 526 /**
 527  *      handle_percpu_IRQ - Per CPU local irq handler
 528  *      @irq:   the interrupt number
 529  *      @desc:  the interrupt description structure for this irq
 530  *
 531  *      Per CPU interrupts on SMP machines without locking requirements
 532  */
 533 void
 534 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
 535 {
 536         irqreturn_t action_ret;
 537
 538         kstat_irqs_this_cpu(desc)++;
 539
 540         if (desc->chip->ack)
 541                 desc->chip->ack(irq);
 542
 543         action_ret = handle_IRQ_event(irq, desc->action);
 544         if (!noirqdebug)
 545                 note_interrupt(irq, desc, action_ret);
 546
 547         if (desc->chip->eoi)
 548                 desc->chip->eoi(irq);
 549 }
 550
 551 void
 552 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
 553                   const char *name)
 554 {
 555         struct irq_desc *desc;
 556         unsigned long flags;
 557
 558         desc = irq_to_desc(irq);
 559         if (!desc) {
 560                 printk(KERN_ERR
 561                        "Trying to install type control for IRQ%d\n", irq);
 562                 return;
 563         }
 564
 565         if (!handle)
 566                 handle = handle_bad_irq;
 567         else if (desc->chip == &no_irq_chip) {
 568                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 569                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
 570                 /*
 571                  * Some ARM implementations install a handler for really dumb
 572                  * interrupt hardware without setting an irq_chip. This worked
 573                  * with the ARM no_irq_chip but the check in setup_irq would
 574                  * prevent us to setup the interrupt at all. Switch it to
 575                  * dummy_irq_chip for easy transition.
 576                  */
 577                 desc->chip = &dummy_irq_chip;
 578         }
 579
 580         spin_lock_irqsave(&desc->lock, flags);
 581
 582         /* Uninstall? */
 583         if (handle == handle_bad_irq) {
 584                 if (desc->chip != &no_irq_chip)
 585                         mask_ack_irq(desc, irq);
 586                 desc->status |= IRQ_DISABLED;
 587                 desc->depth = 1;
 588         }
 589         desc->handle_irq = handle;
 590         desc->name = name;
 591
 592         if (handle != handle_bad_irq && is_chained) {
 593                 desc->status &= ~IRQ_DISABLED;
 594                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 595                 desc->depth = 0;
 596                 desc->chip->startup(irq);
 597         }
 598         spin_unlock_irqrestore(&desc->lock, flags);
 599 }
 600
 601 void
 602 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 603                          irq_flow_handler_t handle)
 604 {
 605         set_irq_chip(irq, chip);
 606         __set_irq_handler(irq, handle, 0, NULL);
 607 }
 608
 609 void
 610 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
 611                               irq_flow_handler_t handle, const char *name)
 612 {
 613         set_irq_chip(irq, chip);
 614         __set_irq_handler(irq, handle, 0, name);
 615 }
 616
 617 void __init set_irq_noprobe(unsigned int irq)
 618 {
 619         struct irq_desc *desc;
 620         unsigned long flags;
 621
 622         desc = irq_to_desc(irq);
 623         if (!desc) {
 624                 printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);
 625
 626                 return;
 627         }
 628
 629         spin_lock_irqsave(&desc->lock, flags);
 630         desc->status |= IRQ_NOPROBE;
 631         spin_unlock_irqrestore(&desc->lock, flags);
 632 }
 633
 634 void __init set_irq_probe(unsigned int irq)
 635 {
 636         struct irq_desc *desc;
 637         unsigned long flags;
 638
 639         desc = irq_to_desc(irq);
 640         if (!desc) {
 641                 printk(KERN_ERR "Trying to mark IRQ%d probeable\n", irq);
 642
 643                 return;
 644         }
 645
 646         spin_lock_irqsave(&desc->lock, flags);
 647         desc->status &= ~IRQ_NOPROBE;
 648         spin_unlock_irqrestore(&desc->lock, flags);
 649 }