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/module.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/kernel_stat.h>
  17
  18 #include "internals.h"
  19
  20 /**
  21  *      dynamic_irq_init - initialize a dynamically allocated irq
  22  *      @irq:   irq number to initialize
  23  */
  24 void dynamic_irq_init(unsigned int irq)
  25 {
  26         struct irq_desc *desc;
  27         unsigned long flags;
  28
  29         if (irq >= NR_IRQS) {
  30                 printk(KERN_ERR "Trying to initialize invalid IRQ%d\n", irq);
  31                 WARN_ON(1);
  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         desc->affinity = CPU_MASK_ALL;
  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                 printk(KERN_ERR "Trying to cleanup invalid IRQ%d\n", irq);
  65                 WARN_ON(1);
  66                 return;
  67         }
  68
  69         desc = irq_desc + irq;
  70         spin_lock_irqsave(&desc->lock, flags);
  71         if (desc->action) {
  72                 spin_unlock_irqrestore(&desc->lock, flags);
  73                 printk(KERN_ERR "Destroying IRQ%d without calling free_irq\n",
  74                         irq);
  75                 WARN_ON(1);
  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         spin_unlock_irqrestore(&desc->lock, flags);
  84 }
  85
  86
  87 /**
  88  *      set_irq_chip - set the irq chip for an irq
  89  *      @irq:   irq number
  90  *      @chip:  pointer to irq chip description structure
  91  */
  92 int set_irq_chip(unsigned int irq, struct irq_chip *chip)
  93 {
  94         struct irq_desc *desc;
  95         unsigned long flags;
  96
  97         if (irq >= NR_IRQS) {
  98                 printk(KERN_ERR "Trying to install chip for IRQ%d\n", irq);
  99                 WARN_ON(1);
 100                 return -EINVAL;
 101         }
 102
 103         if (!chip)
 104                 chip = &no_irq_chip;
 105
 106         desc = irq_desc + irq;
 107         spin_lock_irqsave(&desc->lock, flags);
 108         irq_chip_set_defaults(chip);
 109         desc->chip = chip;
 110         spin_unlock_irqrestore(&desc->lock, flags);
 111
 112         return 0;
 113 }
 114 EXPORT_SYMBOL(set_irq_chip);
 115
 116 /**
 117  *      set_irq_type - set the irq type for an irq
 118  *      @irq:   irq number
 119  *      @type:  interrupt type - see include/linux/interrupt.h
 120  */
 121 int set_irq_type(unsigned int irq, unsigned int type)
 122 {
 123         struct irq_desc *desc;
 124         unsigned long flags;
 125         int ret = -ENXIO;
 126
 127         if (irq >= NR_IRQS) {
 128                 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
 129                 return -ENODEV;
 130         }
 131
 132         desc = irq_desc + irq;
 133         if (desc->chip->set_type) {
 134                 spin_lock_irqsave(&desc->lock, flags);
 135                 ret = desc->chip->set_type(irq, type);
 136                 spin_unlock_irqrestore(&desc->lock, flags);
 137         }
 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         if (irq >= NR_IRQS) {
 155                 printk(KERN_ERR
 156                        "Trying to install controller data for IRQ%d\n", irq);
 157                 return -EINVAL;
 158         }
 159
 160         desc = irq_desc + irq;
 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  *      @data:  Pointer to interrupt specific 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         if (irq >= NR_IRQS) {
 181                 printk(KERN_ERR
 182                        "Trying to install msi data for IRQ%d\n", irq);
 183                 return -EINVAL;
 184         }
 185         desc = irq_desc + irq;
 186         spin_lock_irqsave(&desc->lock, flags);
 187         desc->msi_desc = entry;
 188         spin_unlock_irqrestore(&desc->lock, flags);
 189         return 0;
 190 }
 191
 192 /**
 193  *      set_irq_chip_data - set irq chip data for an irq
 194  *      @irq:   Interrupt number
 195  *      @data:  Pointer to chip specific data
 196  *
 197  *      Set the hardware irq chip data for an irq
 198  */
 199 int set_irq_chip_data(unsigned int irq, void *data)
 200 {
 201         struct irq_desc *desc = irq_desc + irq;
 202         unsigned long flags;
 203
 204         if (irq >= NR_IRQS || !desc->chip) {
 205                 printk(KERN_ERR "BUG: bad set_irq_chip_data(IRQ#%d)\n", irq);
 206                 return -EINVAL;
 207         }
 208
 209         spin_lock_irqsave(&desc->lock, flags);
 210         desc->chip_data = data;
 211         spin_unlock_irqrestore(&desc->lock, flags);
 212
 213         return 0;
 214 }
 215 EXPORT_SYMBOL(set_irq_chip_data);
 216
 217 /*
 218  * default enable function
 219  */
 220 static void default_enable(unsigned int irq)
 221 {
 222         struct irq_desc *desc = irq_desc + irq;
 223
 224         desc->chip->unmask(irq);
 225         desc->status &= ~IRQ_MASKED;
 226 }
 227
 228 /*
 229  * default disable function
 230  */
 231 static void default_disable(unsigned int irq)
 232 {
 233 }
 234
 235 /*
 236  * default startup function
 237  */
 238 static unsigned int default_startup(unsigned int irq)
 239 {
 240         irq_desc[irq].chip->enable(irq);
 241
 242         return 0;
 243 }
 244
 245 /*
 246  * Fixup enable/disable function pointers
 247  */
 248 void irq_chip_set_defaults(struct irq_chip *chip)
 249 {
 250         if (!chip->enable)
 251                 chip->enable = default_enable;
 252         if (!chip->disable)
 253                 chip->disable = default_disable;
 254         if (!chip->startup)
 255                 chip->startup = default_startup;
 256         if (!chip->shutdown)
 257                 chip->shutdown = chip->disable;
 258         if (!chip->name)
 259                 chip->name = chip->typename;
 260         if (!chip->end)
 261                 chip->end = dummy_irq_chip.end;
 262 }
 263
 264 static inline void mask_ack_irq(struct irq_desc *desc, int irq)
 265 {
 266         if (desc->chip->mask_ack)
 267                 desc->chip->mask_ack(irq);
 268         else {
 269                 desc->chip->mask(irq);
 270                 desc->chip->ack(irq);
 271         }
 272 }
 273
 274 /**
 275  *      handle_simple_irq - Simple and software-decoded IRQs.
 276  *      @irq:   the interrupt number
 277  *      @desc:  the interrupt description structure for this irq
 278  *
 279  *      Simple interrupts are either sent from a demultiplexing interrupt
 280  *      handler or come from hardware, where no interrupt hardware control
 281  *      is necessary.
 282  *
 283  *      Note: The caller is expected to handle the ack, clear, mask and
 284  *      unmask issues if necessary.
 285  */
 286 void fastcall
 287 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
 288 {
 289         struct irqaction *action;
 290         irqreturn_t action_ret;
 291         const unsigned int cpu = smp_processor_id();
 292
 293         spin_lock(&desc->lock);
 294
 295         if (unlikely(desc->status & IRQ_INPROGRESS))
 296                 goto out_unlock;
 297         kstat_cpu(cpu).irqs[irq]++;
 298
 299         action = desc->action;
 300         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 301                 if (desc->chip->mask)
 302                         desc->chip->mask(irq);
 303                 desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 304                 desc->status |= IRQ_PENDING;
 305                 goto out_unlock;
 306         }
 307
 308         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING | IRQ_PENDING);
 309         desc->status |= IRQ_INPROGRESS;
 310         spin_unlock(&desc->lock);
 311
 312         action_ret = handle_IRQ_event(irq, action);
 313         if (!noirqdebug)
 314                 note_interrupt(irq, desc, action_ret);
 315
 316         spin_lock(&desc->lock);
 317         desc->status &= ~IRQ_INPROGRESS;
 318 out_unlock:
 319         spin_unlock(&desc->lock);
 320 }
 321
 322 /**
 323  *      handle_level_irq - Level type irq handler
 324  *      @irq:   the interrupt number
 325  *      @desc:  the interrupt description structure for this irq
 326  *
 327  *      Level type interrupts are active as long as the hardware line has
 328  *      the active level. This may require to mask the interrupt and unmask
 329  *      it after the associated handler has acknowledged the device, so the
 330  *      interrupt line is back to inactive.
 331  */
 332 void fastcall
 333 handle_level_irq(unsigned int irq, struct irq_desc *desc)
 334 {
 335         unsigned int cpu = smp_processor_id();
 336         struct irqaction *action;
 337         irqreturn_t action_ret;
 338
 339         spin_lock(&desc->lock);
 340         mask_ack_irq(desc, irq);
 341
 342         if (unlikely(desc->status & IRQ_INPROGRESS))
 343                 goto out_unlock;
 344         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 345         kstat_cpu(cpu).irqs[irq]++;
 346
 347         /*
 348          * If its disabled or no action available
 349          * keep it masked and get out of here
 350          */
 351         action = desc->action;
 352         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 353                 desc->status |= IRQ_PENDING;
 354                 goto out_unlock;
 355         }
 356
 357         desc->status |= IRQ_INPROGRESS;
 358         desc->status &= ~IRQ_PENDING;
 359         spin_unlock(&desc->lock);
 360
 361         action_ret = handle_IRQ_event(irq, action);
 362         if (!noirqdebug)
 363                 note_interrupt(irq, desc, action_ret);
 364
 365         spin_lock(&desc->lock);
 366         desc->status &= ~IRQ_INPROGRESS;
 367         if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
 368                 desc->chip->unmask(irq);
 369 out_unlock:
 370         spin_unlock(&desc->lock);
 371 }
 372
 373 /**
 374  *      handle_fasteoi_irq - irq handler for transparent controllers
 375  *      @irq:   the interrupt number
 376  *      @desc:  the interrupt description structure for this irq
 377  *
 378  *      Only a single callback will be issued to the chip: an ->eoi()
 379  *      call when the interrupt has been serviced. This enables support
 380  *      for modern forms of interrupt handlers, which handle the flow
 381  *      details in hardware, transparently.
 382  */
 383 void fastcall
 384 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 385 {
 386         unsigned int cpu = smp_processor_id();
 387         struct irqaction *action;
 388         irqreturn_t action_ret;
 389
 390         spin_lock(&desc->lock);
 391
 392         if (unlikely(desc->status & IRQ_INPROGRESS))
 393                 goto out;
 394
 395         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 396         kstat_cpu(cpu).irqs[irq]++;
 397
 398         /*
 399          * If its disabled or no action available
 400          * then mask it and get out of here:
 401          */
 402         action = desc->action;
 403         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 404                 desc->status |= IRQ_PENDING;
 405                 if (desc->chip->mask)
 406                         desc->chip->mask(irq);
 407                 goto out;
 408         }
 409
 410         desc->status |= IRQ_INPROGRESS;
 411         desc->status &= ~IRQ_PENDING;
 412         spin_unlock(&desc->lock);
 413
 414         action_ret = handle_IRQ_event(irq, action);
 415         if (!noirqdebug)
 416                 note_interrupt(irq, desc, action_ret);
 417
 418         spin_lock(&desc->lock);
 419         desc->status &= ~IRQ_INPROGRESS;
 420 out:
 421         desc->chip->eoi(irq);
 422
 423         spin_unlock(&desc->lock);
 424 }
 425
 426 /**
 427  *      handle_edge_irq - edge type IRQ handler
 428  *      @irq:   the interrupt number
 429  *      @desc:  the interrupt description structure for this irq
 430  *
 431  *      Interrupt occures on the falling and/or rising edge of a hardware
 432  *      signal. The occurence is latched into the irq controller hardware
 433  *      and must be acked in order to be reenabled. After the ack another
 434  *      interrupt can happen on the same source even before the first one
 435  *      is handled by the assosiacted event handler. If this happens it
 436  *      might be necessary to disable (mask) the interrupt depending on the
 437  *      controller hardware. This requires to reenable the interrupt inside
 438  *      of the loop which handles the interrupts which have arrived while
 439  *      the handler was running. If all pending interrupts are handled, the
 440  *      loop is left.
 441  */
 442 void fastcall
 443 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
 444 {
 445         const unsigned int cpu = smp_processor_id();
 446
 447         spin_lock(&desc->lock);
 448
 449         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 450
 451         /*
 452          * If we're currently running this IRQ, or its disabled,
 453          * we shouldn't process the IRQ. Mark it pending, handle
 454          * the necessary masking and go out
 455          */
 456         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 457                     !desc->action)) {
 458                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 459                 mask_ack_irq(desc, irq);
 460                 goto out_unlock;
 461         }
 462
 463         kstat_cpu(cpu).irqs[irq]++;
 464
 465         /* Start handling the irq */
 466         desc->chip->ack(irq);
 467
 468         /* Mark the IRQ currently in progress.*/
 469         desc->status |= IRQ_INPROGRESS;
 470
 471         do {
 472                 struct irqaction *action = desc->action;
 473                 irqreturn_t action_ret;
 474
 475                 if (unlikely(!action)) {
 476                         desc->chip->mask(irq);
 477                         goto out_unlock;
 478                 }
 479
 480                 /*
 481                  * When another irq arrived while we were handling
 482                  * one, we could have masked the irq.
 483                  * Renable it, if it was not disabled in meantime.
 484                  */
 485                 if (unlikely((desc->status &
 486                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 487                               (IRQ_PENDING | IRQ_MASKED))) {
 488                         desc->chip->unmask(irq);
 489                         desc->status &= ~IRQ_MASKED;
 490                 }
 491
 492                 desc->status &= ~IRQ_PENDING;
 493                 spin_unlock(&desc->lock);
 494                 action_ret = handle_IRQ_event(irq, action);
 495                 if (!noirqdebug)
 496                         note_interrupt(irq, desc, action_ret);
 497                 spin_lock(&desc->lock);
 498
 499         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 500
 501         desc->status &= ~IRQ_INPROGRESS;
 502 out_unlock:
 503         spin_unlock(&desc->lock);
 504 }
 505
 506 #ifdef CONFIG_SMP
 507 /**
 508  *      handle_percpu_IRQ - Per CPU local irq handler
 509  *      @irq:   the interrupt number
 510  *      @desc:  the interrupt description structure for this irq
 511  *
 512  *      Per CPU interrupts on SMP machines without locking requirements
 513  */
 514 void fastcall
 515 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
 516 {
 517         irqreturn_t action_ret;
 518
 519         kstat_this_cpu.irqs[irq]++;
 520
 521         if (desc->chip->ack)
 522                 desc->chip->ack(irq);
 523
 524         action_ret = handle_IRQ_event(irq, desc->action);
 525         if (!noirqdebug)
 526                 note_interrupt(irq, desc, action_ret);
 527
 528         if (desc->chip->eoi)
 529                 desc->chip->eoi(irq);
 530 }
 531
 532 #endif /* CONFIG_SMP */
 533
 534 void
 535 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
 536                   const char *name)
 537 {
 538         struct irq_desc *desc;
 539         unsigned long flags;
 540
 541         if (irq >= NR_IRQS) {
 542                 printk(KERN_ERR
 543                        "Trying to install type control for IRQ%d\n", irq);
 544                 return;
 545         }
 546
 547         desc = irq_desc + irq;
 548
 549         if (!handle)
 550                 handle = handle_bad_irq;
 551         else if (desc->chip == &no_irq_chip) {
 552                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 553                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
 554                 /*
 555                  * Some ARM implementations install a handler for really dumb
 556                  * interrupt hardware without setting an irq_chip. This worked
 557                  * with the ARM no_irq_chip but the check in setup_irq would
 558                  * prevent us to setup the interrupt at all. Switch it to
 559                  * dummy_irq_chip for easy transition.
 560                  */
 561                 desc->chip = &dummy_irq_chip;
 562         }
 563
 564         spin_lock_irqsave(&desc->lock, flags);
 565
 566         /* Uninstall? */
 567         if (handle == handle_bad_irq) {
 568                 if (desc->chip != &no_irq_chip) {
 569                         desc->chip->mask(irq);
 570                         desc->chip->ack(irq);
 571                 }
 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->unmask(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 }