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         struct irq_desc *desc = irq_desc + irq;
 234
 235         if (!(desc->status & IRQ_DELAYED_DISABLE))
 236                 desc->chip->mask(irq);
 237 }
 238
 239 /*
 240  * default startup function
 241  */
 242 static unsigned int default_startup(unsigned int irq)
 243 {
 244         irq_desc[irq].chip->enable(irq);
 245
 246         return 0;
 247 }
 248
 249 /*
 250  * Fixup enable/disable function pointers
 251  */
 252 void irq_chip_set_defaults(struct irq_chip *chip)
 253 {
 254         if (!chip->enable)
 255                 chip->enable = default_enable;
 256         if (!chip->disable)
 257                 chip->disable = default_disable;
 258         if (!chip->startup)
 259                 chip->startup = default_startup;
 260         if (!chip->shutdown)
 261                 chip->shutdown = chip->disable;
 262         if (!chip->name)
 263                 chip->name = chip->typename;
 264         if (!chip->end)
 265                 chip->end = dummy_irq_chip.end;
 266 }
 267
 268 static inline void mask_ack_irq(struct irq_desc *desc, int irq)
 269 {
 270         if (desc->chip->mask_ack)
 271                 desc->chip->mask_ack(irq);
 272         else {
 273                 desc->chip->mask(irq);
 274                 desc->chip->ack(irq);
 275         }
 276 }
 277
 278 /**
 279  *      handle_simple_irq - Simple and software-decoded IRQs.
 280  *      @irq:   the interrupt number
 281  *      @desc:  the interrupt description structure for this irq
 282  *
 283  *      Simple interrupts are either sent from a demultiplexing interrupt
 284  *      handler or come from hardware, where no interrupt hardware control
 285  *      is necessary.
 286  *
 287  *      Note: The caller is expected to handle the ack, clear, mask and
 288  *      unmask issues if necessary.
 289  */
 290 void fastcall
 291 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
 292 {
 293         struct irqaction *action;
 294         irqreturn_t action_ret;
 295         const unsigned int cpu = smp_processor_id();
 296
 297         spin_lock(&desc->lock);
 298
 299         if (unlikely(desc->status & IRQ_INPROGRESS))
 300                 goto out_unlock;
 301         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 302         kstat_cpu(cpu).irqs[irq]++;
 303
 304         action = desc->action;
 305         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 306                 goto out_unlock;
 307
 308         desc->status |= IRQ_INPROGRESS;
 309         spin_unlock(&desc->lock);
 310
 311         action_ret = handle_IRQ_event(irq, action);
 312         if (!noirqdebug)
 313                 note_interrupt(irq, desc, action_ret);
 314
 315         spin_lock(&desc->lock);
 316         desc->status &= ~IRQ_INPROGRESS;
 317 out_unlock:
 318         spin_unlock(&desc->lock);
 319 }
 320
 321 /**
 322  *      handle_level_irq - Level type irq handler
 323  *      @irq:   the interrupt number
 324  *      @desc:  the interrupt description structure for this irq
 325  *
 326  *      Level type interrupts are active as long as the hardware line has
 327  *      the active level. This may require to mask the interrupt and unmask
 328  *      it after the associated handler has acknowledged the device, so the
 329  *      interrupt line is back to inactive.
 330  */
 331 void fastcall
 332 handle_level_irq(unsigned int irq, struct irq_desc *desc)
 333 {
 334         unsigned int cpu = smp_processor_id();
 335         struct irqaction *action;
 336         irqreturn_t action_ret;
 337
 338         spin_lock(&desc->lock);
 339         mask_ack_irq(desc, irq);
 340
 341         if (unlikely(desc->status & IRQ_INPROGRESS))
 342                 goto out_unlock;
 343         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 344         kstat_cpu(cpu).irqs[irq]++;
 345
 346         /*
 347          * If its disabled or no action available
 348          * keep it masked and get out of here
 349          */
 350         action = desc->action;
 351         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 352                 desc->status |= IRQ_PENDING;
 353                 goto out_unlock;
 354         }
 355
 356         desc->status |= IRQ_INPROGRESS;
 357         desc->status &= ~IRQ_PENDING;
 358         spin_unlock(&desc->lock);
 359
 360         action_ret = handle_IRQ_event(irq, action);
 361         if (!noirqdebug)
 362                 note_interrupt(irq, desc, action_ret);
 363
 364         spin_lock(&desc->lock);
 365         desc->status &= ~IRQ_INPROGRESS;
 366         if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
 367                 desc->chip->unmask(irq);
 368 out_unlock:
 369         spin_unlock(&desc->lock);
 370 }
 371
 372 /**
 373  *      handle_fasteoi_irq - irq handler for transparent controllers
 374  *      @irq:   the interrupt number
 375  *      @desc:  the interrupt description structure for this irq
 376  *
 377  *      Only a single callback will be issued to the chip: an ->eoi()
 378  *      call when the interrupt has been serviced. This enables support
 379  *      for modern forms of interrupt handlers, which handle the flow
 380  *      details in hardware, transparently.
 381  */
 382 void fastcall
 383 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 384 {
 385         unsigned int cpu = smp_processor_id();
 386         struct irqaction *action;
 387         irqreturn_t action_ret;
 388
 389         spin_lock(&desc->lock);
 390
 391         if (unlikely(desc->status & IRQ_INPROGRESS))
 392                 goto out;
 393
 394         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 395         kstat_cpu(cpu).irqs[irq]++;
 396
 397         /*
 398          * If its disabled or no action available
 399          * keep it masked and get out of here
 400          */
 401         action = desc->action;
 402         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 403                 desc->status |= IRQ_PENDING;
 404                 goto out;
 405         }
 406
 407         desc->status |= IRQ_INPROGRESS;
 408         desc->status &= ~IRQ_PENDING;
 409         spin_unlock(&desc->lock);
 410
 411         action_ret = handle_IRQ_event(irq, action);
 412         if (!noirqdebug)
 413                 note_interrupt(irq, desc, action_ret);
 414
 415         spin_lock(&desc->lock);
 416         desc->status &= ~IRQ_INPROGRESS;
 417 out:
 418         desc->chip->eoi(irq);
 419
 420         spin_unlock(&desc->lock);
 421 }
 422
 423 /**
 424  *      handle_edge_irq - edge type IRQ handler
 425  *      @irq:   the interrupt number
 426  *      @desc:  the interrupt description structure for this irq
 427  *
 428  *      Interrupt occures on the falling and/or rising edge of a hardware
 429  *      signal. The occurence is latched into the irq controller hardware
 430  *      and must be acked in order to be reenabled. After the ack another
 431  *      interrupt can happen on the same source even before the first one
 432  *      is handled by the assosiacted event handler. If this happens it
 433  *      might be necessary to disable (mask) the interrupt depending on the
 434  *      controller hardware. This requires to reenable the interrupt inside
 435  *      of the loop which handles the interrupts which have arrived while
 436  *      the handler was running. If all pending interrupts are handled, the
 437  *      loop is left.
 438  */
 439 void fastcall
 440 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
 441 {
 442         const unsigned int cpu = smp_processor_id();
 443
 444         spin_lock(&desc->lock);
 445
 446         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 447
 448         /*
 449          * If we're currently running this IRQ, or its disabled,
 450          * we shouldn't process the IRQ. Mark it pending, handle
 451          * the necessary masking and go out
 452          */
 453         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 454                     !desc->action)) {
 455                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 456                 mask_ack_irq(desc, irq);
 457                 goto out_unlock;
 458         }
 459
 460         kstat_cpu(cpu).irqs[irq]++;
 461
 462         /* Start handling the irq */
 463         desc->chip->ack(irq);
 464
 465         /* Mark the IRQ currently in progress.*/
 466         desc->status |= IRQ_INPROGRESS;
 467
 468         do {
 469                 struct irqaction *action = desc->action;
 470                 irqreturn_t action_ret;
 471
 472                 if (unlikely(!action)) {
 473                         desc->chip->mask(irq);
 474                         goto out_unlock;
 475                 }
 476
 477                 /*
 478                  * When another irq arrived while we were handling
 479                  * one, we could have masked the irq.
 480                  * Renable it, if it was not disabled in meantime.
 481                  */
 482                 if (unlikely((desc->status &
 483                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 484                               (IRQ_PENDING | IRQ_MASKED))) {
 485                         desc->chip->unmask(irq);
 486                         desc->status &= ~IRQ_MASKED;
 487                 }
 488
 489                 desc->status &= ~IRQ_PENDING;
 490                 spin_unlock(&desc->lock);
 491                 action_ret = handle_IRQ_event(irq, action);
 492                 if (!noirqdebug)
 493                         note_interrupt(irq, desc, action_ret);
 494                 spin_lock(&desc->lock);
 495
 496         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 497
 498         desc->status &= ~IRQ_INPROGRESS;
 499 out_unlock:
 500         spin_unlock(&desc->lock);
 501 }
 502
 503 #ifdef CONFIG_SMP
 504 /**
 505  *      handle_percpu_IRQ - Per CPU local irq handler
 506  *      @irq:   the interrupt number
 507  *      @desc:  the interrupt description structure for this irq
 508  *
 509  *      Per CPU interrupts on SMP machines without locking requirements
 510  */
 511 void fastcall
 512 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
 513 {
 514         irqreturn_t action_ret;
 515
 516         kstat_this_cpu.irqs[irq]++;
 517
 518         if (desc->chip->ack)
 519                 desc->chip->ack(irq);
 520
 521         action_ret = handle_IRQ_event(irq, desc->action);
 522         if (!noirqdebug)
 523                 note_interrupt(irq, desc, action_ret);
 524
 525         if (desc->chip->eoi)
 526                 desc->chip->eoi(irq);
 527 }
 528
 529 #endif /* CONFIG_SMP */
 530
 531 void
 532 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
 533                   const char *name)
 534 {
 535         struct irq_desc *desc;
 536         unsigned long flags;
 537
 538         if (irq >= NR_IRQS) {
 539                 printk(KERN_ERR
 540                        "Trying to install type control for IRQ%d\n", irq);
 541                 return;
 542         }
 543
 544         desc = irq_desc + irq;
 545
 546         if (!handle)
 547                 handle = handle_bad_irq;
 548         else if (desc->chip == &no_irq_chip) {
 549                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 550                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
 551                 /*
 552                  * Some ARM implementations install a handler for really dumb
 553                  * interrupt hardware without setting an irq_chip. This worked
 554                  * with the ARM no_irq_chip but the check in setup_irq would
 555                  * prevent us to setup the interrupt at all. Switch it to
 556                  * dummy_irq_chip for easy transition.
 557                  */
 558                 desc->chip = &dummy_irq_chip;
 559         }
 560
 561         spin_lock_irqsave(&desc->lock, flags);
 562
 563         /* Uninstall? */
 564         if (handle == handle_bad_irq) {
 565                 if (desc->chip != &no_irq_chip) {
 566                         desc->chip->mask(irq);
 567                         desc->chip->ack(irq);
 568                 }
 569                 desc->status |= IRQ_DISABLED;
 570                 desc->depth = 1;
 571         }
 572         desc->handle_irq = handle;
 573         desc->name = name;
 574
 575         if (handle != handle_bad_irq && is_chained) {
 576                 desc->status &= ~IRQ_DISABLED;
 577                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 578                 desc->depth = 0;
 579                 desc->chip->unmask(irq);
 580         }
 581         spin_unlock_irqrestore(&desc->lock, flags);
 582 }
 583
 584 void
 585 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 586                          irq_flow_handler_t handle)
 587 {
 588         set_irq_chip(irq, chip);
 589         __set_irq_handler(irq, handle, 0, NULL);
 590 }
 591
 592 void
 593 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
 594                               irq_flow_handler_t handle, const char *name)
 595 {
 596         set_irq_chip(irq, chip);
 597         __set_irq_handler(irq, handle, 0, name);
 598 }