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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                 printk(KERN_ERR "Trying to initialize invalid IRQ%d\n", irq);
  32                 WARN_ON(1);
  33                 return;
  34         }
  35
  36         /* Ensure we don't have left over values from a previous use of this irq */
  37         desc = irq_desc + 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         desc->affinity = CPU_MASK_ALL;
  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         if (irq >= NR_IRQS) {
  65                 printk(KERN_ERR "Trying to cleanup invalid IRQ%d\n", irq);
  66                 WARN_ON(1);
  67                 return;
  68         }
  69
  70         desc = irq_desc + irq;
  71         spin_lock_irqsave(&desc->lock, flags);
  72         if (desc->action) {
  73                 spin_unlock_irqrestore(&desc->lock, flags);
  74                 printk(KERN_ERR "Destroying IRQ%d without calling free_irq\n",
  75                         irq);
  76                 WARN_ON(1);
  77                 return;
  78         }
  79         desc->msi_desc = NULL;
  80         desc->handler_data = NULL;
  81         desc->chip_data = NULL;
  82         desc->handle_irq = handle_bad_irq;
  83         desc->chip = &no_irq_chip;
  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;
  96         unsigned long flags;
  97
  98         if (irq >= NR_IRQS) {
  99                 printk(KERN_ERR "Trying to install chip for IRQ%d\n", irq);
 100                 WARN_ON(1);
 101                 return -EINVAL;
 102         }
 103
 104         if (!chip)
 105                 chip = &no_irq_chip;
 106
 107         desc = irq_desc + irq;
 108         spin_lock_irqsave(&desc->lock, flags);
 109         irq_chip_set_defaults(chip);
 110         desc->chip = chip;
 111         spin_unlock_irqrestore(&desc->lock, flags);
 112
 113         return 0;
 114 }
 115 EXPORT_SYMBOL(set_irq_chip);
 116
 117 /**
 118  *      set_irq_type - set the irq type for an irq
 119  *      @irq:   irq number
 120  *      @type:  interrupt type - see include/linux/interrupt.h
 121  */
 122 int set_irq_type(unsigned int irq, unsigned int type)
 123 {
 124         struct irq_desc *desc;
 125         unsigned long flags;
 126         int ret = -ENXIO;
 127
 128         if (irq >= NR_IRQS) {
 129                 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
 130                 return -ENODEV;
 131         }
 132
 133         desc = irq_desc + irq;
 134         if (desc->chip->set_type) {
 135                 spin_lock_irqsave(&desc->lock, flags);
 136                 ret = desc->chip->set_type(irq, type);
 137                 spin_unlock_irqrestore(&desc->lock, flags);
 138         }
 139         return ret;
 140 }
 141 EXPORT_SYMBOL(set_irq_type);
 142
 143 /**
 144  *      set_irq_data - set irq type data for an irq
 145  *      @irq:   Interrupt number
 146  *      @data:  Pointer to interrupt specific data
 147  *
 148  *      Set the hardware irq controller data for an irq
 149  */
 150 int set_irq_data(unsigned int irq, void *data)
 151 {
 152         struct irq_desc *desc;
 153         unsigned long flags;
 154
 155         if (irq >= NR_IRQS) {
 156                 printk(KERN_ERR
 157                        "Trying to install controller data for IRQ%d\n", irq);
 158                 return -EINVAL;
 159         }
 160
 161         desc = irq_desc + irq;
 162         spin_lock_irqsave(&desc->lock, flags);
 163         desc->handler_data = data;
 164         spin_unlock_irqrestore(&desc->lock, flags);
 165         return 0;
 166 }
 167 EXPORT_SYMBOL(set_irq_data);
 168
 169 /**
 170  *      set_irq_data - set irq type data for an irq
 171  *      @irq:   Interrupt number
 172  *      @entry: Pointer to MSI descriptor data
 173  *
 174  *      Set the hardware irq controller data for an irq
 175  */
 176 int set_irq_msi(unsigned int irq, struct msi_desc *entry)
 177 {
 178         struct irq_desc *desc;
 179         unsigned long flags;
 180
 181         if (irq >= NR_IRQS) {
 182                 printk(KERN_ERR
 183                        "Trying to install msi data for IRQ%d\n", irq);
 184                 return -EINVAL;
 185         }
 186         desc = irq_desc + irq;
 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 = irq_desc + irq;
 205         unsigned long flags;
 206
 207         if (irq >= NR_IRQS || !desc->chip) {
 208                 printk(KERN_ERR "BUG: bad set_irq_chip_data(IRQ#%d)\n", irq);
 209                 return -EINVAL;
 210         }
 211
 212         spin_lock_irqsave(&desc->lock, flags);
 213         desc->chip_data = data;
 214         spin_unlock_irqrestore(&desc->lock, flags);
 215
 216         return 0;
 217 }
 218 EXPORT_SYMBOL(set_irq_chip_data);
 219
 220 /*
 221  * default enable function
 222  */
 223 static void default_enable(unsigned int irq)
 224 {
 225         struct irq_desc *desc = irq_desc + irq;
 226
 227         desc->chip->unmask(irq);
 228         desc->status &= ~IRQ_MASKED;
 229 }
 230
 231 /*
 232  * default disable function
 233  */
 234 static void default_disable(unsigned int irq)
 235 {
 236 }
 237
 238 /*
 239  * default startup function
 240  */
 241 static unsigned int default_startup(unsigned int irq)
 242 {
 243         irq_desc[irq].chip->enable(irq);
 244
 245         return 0;
 246 }
 247
 248 /*
 249  * default shutdown function
 250  */
 251 static void default_shutdown(unsigned int irq)
 252 {
 253         struct irq_desc *desc = irq_desc + irq;
 254
 255         desc->chip->mask(irq);
 256         desc->status |= IRQ_MASKED;
 257 }
 258
 259 /*
 260  * Fixup enable/disable function pointers
 261  */
 262 void irq_chip_set_defaults(struct irq_chip *chip)
 263 {
 264         if (!chip->enable)
 265                 chip->enable = default_enable;
 266         if (!chip->disable)
 267                 chip->disable = default_disable;
 268         if (!chip->startup)
 269                 chip->startup = default_startup;
 270         /*
 271          * We use chip->disable, when the user provided its own. When
 272          * we have default_disable set for chip->disable, then we need
 273          * to use default_shutdown, otherwise the irq line is not
 274          * disabled on free_irq():
 275          */
 276         if (!chip->shutdown)
 277                 chip->shutdown = chip->disable != default_disable ?
 278                         chip->disable : default_shutdown;
 279         if (!chip->name)
 280                 chip->name = chip->typename;
 281         if (!chip->end)
 282                 chip->end = dummy_irq_chip.end;
 283 }
 284
 285 static inline void mask_ack_irq(struct irq_desc *desc, int irq)
 286 {
 287         if (desc->chip->mask_ack)
 288                 desc->chip->mask_ack(irq);
 289         else {
 290                 desc->chip->mask(irq);
 291                 desc->chip->ack(irq);
 292         }
 293 }
 294
 295 /**
 296  *      handle_simple_irq - Simple and software-decoded IRQs.
 297  *      @irq:   the interrupt number
 298  *      @desc:  the interrupt description structure for this irq
 299  *
 300  *      Simple interrupts are either sent from a demultiplexing interrupt
 301  *      handler or come from hardware, where no interrupt hardware control
 302  *      is necessary.
 303  *
 304  *      Note: The caller is expected to handle the ack, clear, mask and
 305  *      unmask issues if necessary.
 306  */
 307 void
 308 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
 309 {
 310         struct irqaction *action;
 311         irqreturn_t action_ret;
 312         const unsigned int cpu = smp_processor_id();
 313
 314         spin_lock(&desc->lock);
 315
 316         if (unlikely(desc->status & IRQ_INPROGRESS))
 317                 goto out_unlock;
 318         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 319         kstat_cpu(cpu).irqs[irq]++;
 320
 321         action = desc->action;
 322         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 323                 goto out_unlock;
 324
 325         desc->status |= IRQ_INPROGRESS;
 326         spin_unlock(&desc->lock);
 327
 328         action_ret = handle_IRQ_event(irq, action);
 329         if (!noirqdebug)
 330                 note_interrupt(irq, desc, action_ret);
 331
 332         spin_lock(&desc->lock);
 333         desc->status &= ~IRQ_INPROGRESS;
 334 out_unlock:
 335         spin_unlock(&desc->lock);
 336 }
 337
 338 /**
 339  *      handle_level_irq - Level type irq handler
 340  *      @irq:   the interrupt number
 341  *      @desc:  the interrupt description structure for this irq
 342  *
 343  *      Level type interrupts are active as long as the hardware line has
 344  *      the active level. This may require to mask the interrupt and unmask
 345  *      it after the associated handler has acknowledged the device, so the
 346  *      interrupt line is back to inactive.
 347  */
 348 void
 349 handle_level_irq(unsigned int irq, struct irq_desc *desc)
 350 {
 351         unsigned int cpu = smp_processor_id();
 352         struct irqaction *action;
 353         irqreturn_t action_ret;
 354
 355         spin_lock(&desc->lock);
 356         mask_ack_irq(desc, irq);
 357
 358         if (unlikely(desc->status & IRQ_INPROGRESS))
 359                 goto out_unlock;
 360         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 361         kstat_cpu(cpu).irqs[irq]++;
 362
 363         /*
 364          * If its disabled or no action available
 365          * keep it masked and get out of here
 366          */
 367         action = desc->action;
 368         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 369                 goto out_unlock;
 370
 371         desc->status |= IRQ_INPROGRESS;
 372         spin_unlock(&desc->lock);
 373
 374         action_ret = handle_IRQ_event(irq, action);
 375         if (!noirqdebug)
 376                 note_interrupt(irq, desc, action_ret);
 377
 378         spin_lock(&desc->lock);
 379         desc->status &= ~IRQ_INPROGRESS;
 380         if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
 381                 desc->chip->unmask(irq);
 382 out_unlock:
 383         spin_unlock(&desc->lock);
 384 }
 385
 386 /**
 387  *      handle_fasteoi_irq - irq handler for transparent controllers
 388  *      @irq:   the interrupt number
 389  *      @desc:  the interrupt description structure for this irq
 390  *
 391  *      Only a single callback will be issued to the chip: an ->eoi()
 392  *      call when the interrupt has been serviced. This enables support
 393  *      for modern forms of interrupt handlers, which handle the flow
 394  *      details in hardware, transparently.
 395  */
 396 void
 397 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 398 {
 399         unsigned int cpu = smp_processor_id();
 400         struct irqaction *action;
 401         irqreturn_t action_ret;
 402
 403         spin_lock(&desc->lock);
 404
 405         if (unlikely(desc->status & IRQ_INPROGRESS))
 406                 goto out;
 407
 408         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 409         kstat_cpu(cpu).irqs[irq]++;
 410
 411         /*
 412          * If its disabled or no action available
 413          * then mask it and get out of here:
 414          */
 415         action = desc->action;
 416         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 417                 desc->status |= IRQ_PENDING;
 418                 if (desc->chip->mask)
 419                         desc->chip->mask(irq);
 420                 goto out;
 421         }
 422
 423         desc->status |= IRQ_INPROGRESS;
 424         desc->status &= ~IRQ_PENDING;
 425         spin_unlock(&desc->lock);
 426
 427         action_ret = handle_IRQ_event(irq, action);
 428         if (!noirqdebug)
 429                 note_interrupt(irq, desc, action_ret);
 430
 431         spin_lock(&desc->lock);
 432         desc->status &= ~IRQ_INPROGRESS;
 433 out:
 434         desc->chip->eoi(irq);
 435
 436         spin_unlock(&desc->lock);
 437 }
 438
 439 /**
 440  *      handle_edge_irq - edge type IRQ handler
 441  *      @irq:   the interrupt number
 442  *      @desc:  the interrupt description structure for this irq
 443  *
 444  *      Interrupt occures on the falling and/or rising edge of a hardware
 445  *      signal. The occurence is latched into the irq controller hardware
 446  *      and must be acked in order to be reenabled. After the ack another
 447  *      interrupt can happen on the same source even before the first one
 448  *      is handled by the assosiacted event handler. If this happens it
 449  *      might be necessary to disable (mask) the interrupt depending on the
 450  *      controller hardware. This requires to reenable the interrupt inside
 451  *      of the loop which handles the interrupts which have arrived while
 452  *      the handler was running. If all pending interrupts are handled, the
 453  *      loop is left.
 454  */
 455 void
 456 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
 457 {
 458         const unsigned int cpu = smp_processor_id();
 459
 460         spin_lock(&desc->lock);
 461
 462         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 463
 464         /*
 465          * If we're currently running this IRQ, or its disabled,
 466          * we shouldn't process the IRQ. Mark it pending, handle
 467          * the necessary masking and go out
 468          */
 469         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 470                     !desc->action)) {
 471                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 472                 mask_ack_irq(desc, irq);
 473                 goto out_unlock;
 474         }
 475
 476         kstat_cpu(cpu).irqs[irq]++;
 477
 478         /* Start handling the irq */
 479         desc->chip->ack(irq);
 480
 481         /* Mark the IRQ currently in progress.*/
 482         desc->status |= IRQ_INPROGRESS;
 483
 484         do {
 485                 struct irqaction *action = desc->action;
 486                 irqreturn_t action_ret;
 487
 488                 if (unlikely(!action)) {
 489                         desc->chip->mask(irq);
 490                         goto out_unlock;
 491                 }
 492
 493                 /*
 494                  * When another irq arrived while we were handling
 495                  * one, we could have masked the irq.
 496                  * Renable it, if it was not disabled in meantime.
 497                  */
 498                 if (unlikely((desc->status &
 499                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 500                               (IRQ_PENDING | IRQ_MASKED))) {
 501                         desc->chip->unmask(irq);
 502                         desc->status &= ~IRQ_MASKED;
 503                 }
 504
 505                 desc->status &= ~IRQ_PENDING;
 506                 spin_unlock(&desc->lock);
 507                 action_ret = handle_IRQ_event(irq, action);
 508                 if (!noirqdebug)
 509                         note_interrupt(irq, desc, action_ret);
 510                 spin_lock(&desc->lock);
 511
 512         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 513
 514         desc->status &= ~IRQ_INPROGRESS;
 515 out_unlock:
 516         spin_unlock(&desc->lock);
 517 }
 518
 519 /**
 520  *      handle_percpu_IRQ - Per CPU local irq handler
 521  *      @irq:   the interrupt number
 522  *      @desc:  the interrupt description structure for this irq
 523  *
 524  *      Per CPU interrupts on SMP machines without locking requirements
 525  */
 526 void
 527 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
 528 {
 529         irqreturn_t action_ret;
 530
 531         kstat_this_cpu.irqs[irq]++;
 532
 533         if (desc->chip->ack)
 534                 desc->chip->ack(irq);
 535
 536         action_ret = handle_IRQ_event(irq, desc->action);
 537         if (!noirqdebug)
 538                 note_interrupt(irq, desc, action_ret);
 539
 540         if (desc->chip->eoi)
 541                 desc->chip->eoi(irq);
 542 }
 543
 544 void
 545 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
 546                   const char *name)
 547 {
 548         struct irq_desc *desc;
 549         unsigned long flags;
 550
 551         if (irq >= NR_IRQS) {
 552                 printk(KERN_ERR
 553                        "Trying to install type control for IRQ%d\n", irq);
 554                 return;
 555         }
 556
 557         desc = irq_desc + irq;
 558
 559         if (!handle)
 560                 handle = handle_bad_irq;
 561         else if (desc->chip == &no_irq_chip) {
 562                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 563                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
 564                 /*
 565                  * Some ARM implementations install a handler for really dumb
 566                  * interrupt hardware without setting an irq_chip. This worked
 567                  * with the ARM no_irq_chip but the check in setup_irq would
 568                  * prevent us to setup the interrupt at all. Switch it to
 569                  * dummy_irq_chip for easy transition.
 570                  */
 571                 desc->chip = &dummy_irq_chip;
 572         }
 573
 574         spin_lock_irqsave(&desc->lock, flags);
 575
 576         /* Uninstall? */
 577         if (handle == handle_bad_irq) {
 578                 if (desc->chip != &no_irq_chip)
 579                         mask_ack_irq(desc, irq);
 580                 desc->status |= IRQ_DISABLED;
 581                 desc->depth = 1;
 582         }
 583         desc->handle_irq = handle;
 584         desc->name = name;
 585
 586         if (handle != handle_bad_irq && is_chained) {
 587                 desc->status &= ~IRQ_DISABLED;
 588                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 589                 desc->depth = 0;
 590                 desc->chip->unmask(irq);
 591         }
 592         spin_unlock_irqrestore(&desc->lock, flags);
 593 }
 594
 595 void
 596 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 597                          irq_flow_handler_t handle)
 598 {
 599         set_irq_chip(irq, chip);
 600         __set_irq_handler(irq, handle, 0, NULL);
 601 }
 602
 603 void
 604 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
 605                               irq_flow_handler_t handle, const char *name)
 606 {
 607         set_irq_chip(irq, chip);
 608         __set_irq_handler(irq, handle, 0, name);
 609 }
 610
 611 void __init set_irq_noprobe(unsigned int irq)
 612 {
 613         struct irq_desc *desc;
 614         unsigned long flags;
 615
 616         if (irq >= NR_IRQS) {
 617                 printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);
 618
 619                 return;
 620         }
 621
 622         desc = irq_desc + irq;
 623
 624         spin_lock_irqsave(&desc->lock, flags);
 625         desc->status |= IRQ_NOPROBE;
 626         spin_unlock_irqrestore(&desc->lock, flags);
 627 }
 628
 629 void __init set_irq_probe(unsigned int irq)
 630 {
 631         struct irq_desc *desc;
 632         unsigned long flags;
 633
 634         if (irq >= NR_IRQS) {
 635                 printk(KERN_ERR "Trying to mark IRQ%d probeable\n", irq);
 636
 637                 return;
 638         }
 639
 640         desc = irq_desc + irq;
 641
 642         spin_lock_irqsave(&desc->lock, flags);
 643         desc->status &= ~IRQ_NOPROBE;
 644         spin_unlock_irqrestore(&desc->lock, flags);
 645 }