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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         /* 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 #ifdef CONFIG_HAVE_DYN_ARRAY
 331         kstat_irqs_this_cpu(desc)++;
 332 #else
 333         kstat_irqs_this_cpu(irq)++;
 334 #endif
 335
 336         action = desc->action;
 337         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 338                 goto out_unlock;
 339
 340         desc->status |= IRQ_INPROGRESS;
 341         spin_unlock(&desc->lock);
 342
 343         action_ret = handle_IRQ_event(irq, action);
 344         if (!noirqdebug)
 345                 note_interrupt(irq, desc, action_ret);
 346
 347         spin_lock(&desc->lock);
 348         desc->status &= ~IRQ_INPROGRESS;
 349 out_unlock:
 350         spin_unlock(&desc->lock);
 351 }
 352
 353 /**
 354  *      handle_level_irq - Level type irq handler
 355  *      @irq:   the interrupt number
 356  *      @desc:  the interrupt description structure for this irq
 357  *
 358  *      Level type interrupts are active as long as the hardware line has
 359  *      the active level. This may require to mask the interrupt and unmask
 360  *      it after the associated handler has acknowledged the device, so the
 361  *      interrupt line is back to inactive.
 362  */
 363 void
 364 handle_level_irq(unsigned int irq, struct irq_desc *desc)
 365 {
 366         struct irqaction *action;
 367         irqreturn_t action_ret;
 368
 369         spin_lock(&desc->lock);
 370         mask_ack_irq(desc, irq);
 371
 372         if (unlikely(desc->status & IRQ_INPROGRESS))
 373                 goto out_unlock;
 374         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 375 #ifdef CONFIG_HAVE_DYN_ARRAY
 376         kstat_irqs_this_cpu(desc)++;
 377 #else
 378         kstat_irqs_this_cpu(irq)++;
 379 #endif
 380
 381         /*
 382          * If its disabled or no action available
 383          * keep it masked and get out of here
 384          */
 385         action = desc->action;
 386         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 387                 goto out_unlock;
 388
 389         desc->status |= IRQ_INPROGRESS;
 390         spin_unlock(&desc->lock);
 391
 392         action_ret = handle_IRQ_event(irq, action);
 393         if (!noirqdebug)
 394                 note_interrupt(irq, desc, action_ret);
 395
 396         spin_lock(&desc->lock);
 397         desc->status &= ~IRQ_INPROGRESS;
 398         if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
 399                 desc->chip->unmask(irq);
 400 out_unlock:
 401         spin_unlock(&desc->lock);
 402 }
 403
 404 /**
 405  *      handle_fasteoi_irq - irq handler for transparent controllers
 406  *      @irq:   the interrupt number
 407  *      @desc:  the interrupt description structure for this irq
 408  *
 409  *      Only a single callback will be issued to the chip: an ->eoi()
 410  *      call when the interrupt has been serviced. This enables support
 411  *      for modern forms of interrupt handlers, which handle the flow
 412  *      details in hardware, transparently.
 413  */
 414 void
 415 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 416 {
 417         struct irqaction *action;
 418         irqreturn_t action_ret;
 419
 420         spin_lock(&desc->lock);
 421
 422         if (unlikely(desc->status & IRQ_INPROGRESS))
 423                 goto out;
 424
 425         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 426 #ifdef CONFIG_HAVE_DYN_ARRAY
 427         kstat_irqs_this_cpu(desc)++;
 428 #else
 429         kstat_irqs_this_cpu(irq)++;
 430 #endif
 431
 432         /*
 433          * If its disabled or no action available
 434          * then mask it and get out of here:
 435          */
 436         action = desc->action;
 437         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 438                 desc->status |= IRQ_PENDING;
 439                 if (desc->chip->mask)
 440                         desc->chip->mask(irq);
 441                 goto out;
 442         }
 443
 444         desc->status |= IRQ_INPROGRESS;
 445         desc->status &= ~IRQ_PENDING;
 446         spin_unlock(&desc->lock);
 447
 448         action_ret = handle_IRQ_event(irq, action);
 449         if (!noirqdebug)
 450                 note_interrupt(irq, desc, action_ret);
 451
 452         spin_lock(&desc->lock);
 453         desc->status &= ~IRQ_INPROGRESS;
 454 out:
 455         desc->chip->eoi(irq);
 456
 457         spin_unlock(&desc->lock);
 458 }
 459
 460 /**
 461  *      handle_edge_irq - edge type IRQ handler
 462  *      @irq:   the interrupt number
 463  *      @desc:  the interrupt description structure for this irq
 464  *
 465  *      Interrupt occures on the falling and/or rising edge of a hardware
 466  *      signal. The occurence is latched into the irq controller hardware
 467  *      and must be acked in order to be reenabled. After the ack another
 468  *      interrupt can happen on the same source even before the first one
 469  *      is handled by the assosiacted event handler. If this happens it
 470  *      might be necessary to disable (mask) the interrupt depending on the
 471  *      controller hardware. This requires to reenable the interrupt inside
 472  *      of the loop which handles the interrupts which have arrived while
 473  *      the handler was running. If all pending interrupts are handled, the
 474  *      loop is left.
 475  */
 476 void
 477 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
 478 {
 479         spin_lock(&desc->lock);
 480
 481         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 482
 483         /*
 484          * If we're currently running this IRQ, or its disabled,
 485          * we shouldn't process the IRQ. Mark it pending, handle
 486          * the necessary masking and go out
 487          */
 488         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 489                     !desc->action)) {
 490                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 491                 mask_ack_irq(desc, irq);
 492                 goto out_unlock;
 493         }
 494 #ifdef CONFIG_HAVE_DYN_ARRAY
 495         kstat_irqs_this_cpu(desc)++;
 496 #else
 497         kstat_irqs_this_cpu(irq)++;
 498 #endif
 499
 500         /* Start handling the irq */
 501         desc->chip->ack(irq);
 502
 503         /* Mark the IRQ currently in progress.*/
 504         desc->status |= IRQ_INPROGRESS;
 505
 506         do {
 507                 struct irqaction *action = desc->action;
 508                 irqreturn_t action_ret;
 509
 510                 if (unlikely(!action)) {
 511                         desc->chip->mask(irq);
 512                         goto out_unlock;
 513                 }
 514
 515                 /*
 516                  * When another irq arrived while we were handling
 517                  * one, we could have masked the irq.
 518                  * Renable it, if it was not disabled in meantime.
 519                  */
 520                 if (unlikely((desc->status &
 521                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 522                               (IRQ_PENDING | IRQ_MASKED))) {
 523                         desc->chip->unmask(irq);
 524                         desc->status &= ~IRQ_MASKED;
 525                 }
 526
 527                 desc->status &= ~IRQ_PENDING;
 528                 spin_unlock(&desc->lock);
 529                 action_ret = handle_IRQ_event(irq, action);
 530                 if (!noirqdebug)
 531                         note_interrupt(irq, desc, action_ret);
 532                 spin_lock(&desc->lock);
 533
 534         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 535
 536         desc->status &= ~IRQ_INPROGRESS;
 537 out_unlock:
 538         spin_unlock(&desc->lock);
 539 }
 540
 541 /**
 542  *      handle_percpu_IRQ - Per CPU local irq handler
 543  *      @irq:   the interrupt number
 544  *      @desc:  the interrupt description structure for this irq
 545  *
 546  *      Per CPU interrupts on SMP machines without locking requirements
 547  */
 548 void
 549 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
 550 {
 551         irqreturn_t action_ret;
 552
 553 #ifdef CONFIG_HAVE_DYN_ARRAY
 554         kstat_irqs_this_cpu(desc)++;
 555 #else
 556         kstat_irqs_this_cpu(irq)++;
 557 #endif
 558
 559         if (desc->chip->ack)
 560                 desc->chip->ack(irq);
 561
 562         action_ret = handle_IRQ_event(irq, desc->action);
 563         if (!noirqdebug)
 564                 note_interrupt(irq, desc, action_ret);
 565
 566         if (desc->chip->eoi)
 567                 desc->chip->eoi(irq);
 568 }
 569
 570 void
 571 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
 572                   const char *name)
 573 {
 574         struct irq_desc *desc;
 575         unsigned long flags;
 576
 577         desc = irq_to_desc(irq);
 578         if (!desc) {
 579                 printk(KERN_ERR
 580                        "Trying to install type control for IRQ%d\n", irq);
 581                 return;
 582         }
 583
 584         if (!handle)
 585                 handle = handle_bad_irq;
 586         else if (desc->chip == &no_irq_chip) {
 587                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 588                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
 589                 /*
 590                  * Some ARM implementations install a handler for really dumb
 591                  * interrupt hardware without setting an irq_chip. This worked
 592                  * with the ARM no_irq_chip but the check in setup_irq would
 593                  * prevent us to setup the interrupt at all. Switch it to
 594                  * dummy_irq_chip for easy transition.
 595                  */
 596                 desc->chip = &dummy_irq_chip;
 597         }
 598
 599         spin_lock_irqsave(&desc->lock, flags);
 600
 601         /* Uninstall? */
 602         if (handle == handle_bad_irq) {
 603                 if (desc->chip != &no_irq_chip)
 604                         mask_ack_irq(desc, irq);
 605                 desc->status |= IRQ_DISABLED;
 606                 desc->depth = 1;
 607         }
 608         desc->handle_irq = handle;
 609         desc->name = name;
 610
 611         if (handle != handle_bad_irq && is_chained) {
 612                 desc->status &= ~IRQ_DISABLED;
 613                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 614                 desc->depth = 0;
 615                 desc->chip->startup(irq);
 616         }
 617         spin_unlock_irqrestore(&desc->lock, flags);
 618 }
 619
 620 void
 621 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 622                          irq_flow_handler_t handle)
 623 {
 624         set_irq_chip(irq, chip);
 625         __set_irq_handler(irq, handle, 0, NULL);
 626 }
 627
 628 void
 629 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
 630                               irq_flow_handler_t handle, const char *name)
 631 {
 632         set_irq_chip(irq, chip);
 633         __set_irq_handler(irq, handle, 0, name);
 634 }
 635
 636 void __init set_irq_noprobe(unsigned int irq)
 637 {
 638         struct irq_desc *desc;
 639         unsigned long flags;
 640
 641         desc = irq_to_desc(irq);
 642         if (!desc) {
 643                 printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);
 644
 645                 return;
 646         }
 647
 648         spin_lock_irqsave(&desc->lock, flags);
 649         desc->status |= IRQ_NOPROBE;
 650         spin_unlock_irqrestore(&desc->lock, flags);
 651 }
 652
 653 void __init set_irq_probe(unsigned int irq)
 654 {
 655         struct irq_desc *desc;
 656         unsigned long flags;
 657
 658         desc = irq_to_desc(irq);
 659         if (!desc) {
 660                 printk(KERN_ERR "Trying to mark IRQ%d probeable\n", irq);
 661
 662                 return;
 663         }
 664
 665         spin_lock_irqsave(&desc->lock, flags);
 666         desc->status &= ~IRQ_NOPROBE;
 667         spin_unlock_irqrestore(&desc->lock, flags);
 668 }