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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         desc = irq_to_desc(irq);
  31         if (!desc) {
  32                 WARN(1, KERN_ERR "Trying to initialize invalid IRQ%d\n", irq);
  33                 return;
  34         }
  35
  36         /* Ensure we don't have left over values from a previous use of this 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         cpus_setall(desc->affinity);
  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         desc = __irq_to_desc(irq);
  64         if (!desc) {
  65                 WARN(1, KERN_ERR "Trying to cleanup invalid IRQ%d\n", irq);
  66                 return;
  67         }
  68
  69         spin_lock_irqsave(&desc->lock, flags);
  70         if (desc->action) {
  71                 spin_unlock_irqrestore(&desc->lock, flags);
  72                 WARN(1, KERN_ERR "Destroying IRQ%d without calling free_irq\n",
  73                         irq);
  74                 return;
  75         }
  76         desc->msi_desc = NULL;
  77         desc->handler_data = NULL;
  78         desc->chip_data = NULL;
  79         desc->handle_irq = handle_bad_irq;
  80         desc->chip = &no_irq_chip;
  81         spin_unlock_irqrestore(&desc->lock, flags);
  82 }
  83
  84
  85 /**
  86  *      set_irq_chip - set the irq chip for an irq
  87  *      @irq:   irq number
  88  *      @chip:  pointer to irq chip description structure
  89  */
  90 int set_irq_chip(unsigned int irq, struct irq_chip *chip)
  91 {
  92         struct irq_desc *desc;
  93         unsigned long flags;
  94
  95         desc = __irq_to_desc(irq);
  96         if (!desc) {
  97                 WARN(1, KERN_ERR "Trying to install chip for IRQ%d\n", irq);
  98                 return -EINVAL;
  99         }
 100
 101         if (!chip)
 102                 chip = &no_irq_chip;
 103
 104         desc = irq_to_desc(irq);
 105         spin_lock_irqsave(&desc->lock, flags);
 106         irq_chip_set_defaults(chip);
 107         desc->chip = chip;
 108         spin_unlock_irqrestore(&desc->lock, flags);
 109
 110         return 0;
 111 }
 112 EXPORT_SYMBOL(set_irq_chip);
 113
 114 /**
 115  *      set_irq_type - set the irq trigger type for an irq
 116  *      @irq:   irq number
 117  *      @type:  IRQ_TYPE_{LEVEL,EDGE}_* value - see include/linux/irq.h
 118  */
 119 int set_irq_type(unsigned int irq, unsigned int type)
 120 {
 121         struct irq_desc *desc;
 122         unsigned long flags;
 123         int ret = -ENXIO;
 124
 125         desc = __irq_to_desc(irq);
 126         if (!desc) {
 127                 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
 128                 return -ENODEV;
 129         }
 130
 131         if (type == IRQ_TYPE_NONE)
 132                 return 0;
 133
 134         spin_lock_irqsave(&desc->lock, flags);
 135         ret = __irq_set_trigger(desc, irq, flags);
 136         spin_unlock_irqrestore(&desc->lock, flags);
 137         return ret;
 138 }
 139 EXPORT_SYMBOL(set_irq_type);
 140
 141 /**
 142  *      set_irq_data - set irq type data for an irq
 143  *      @irq:   Interrupt number
 144  *      @data:  Pointer to interrupt specific data
 145  *
 146  *      Set the hardware irq controller data for an irq
 147  */
 148 int set_irq_data(unsigned int irq, void *data)
 149 {
 150         struct irq_desc *desc;
 151         unsigned long flags;
 152
 153         desc = __irq_to_desc(irq);
 154         if (!desc) {
 155                 printk(KERN_ERR
 156                        "Trying to install controller data for IRQ%d\n", irq);
 157                 return -EINVAL;
 158         }
 159
 160         spin_lock_irqsave(&desc->lock, flags);
 161         desc->handler_data = data;
 162         spin_unlock_irqrestore(&desc->lock, flags);
 163         return 0;
 164 }
 165 EXPORT_SYMBOL(set_irq_data);
 166
 167 /**
 168  *      set_irq_data - set irq type data for an irq
 169  *      @irq:   Interrupt number
 170  *      @entry: Pointer to MSI descriptor data
 171  *
 172  *      Set the hardware irq controller data for an irq
 173  */
 174 int set_irq_msi(unsigned int irq, struct msi_desc *entry)
 175 {
 176         struct irq_desc *desc;
 177         unsigned long flags;
 178
 179         desc = __irq_to_desc(irq);
 180         if (!desc) {
 181                 printk(KERN_ERR
 182                        "Trying to install msi data for IRQ%d\n", irq);
 183                 return -EINVAL;
 184         }
 185
 186         spin_lock_irqsave(&desc->lock, flags);
 187         desc->msi_desc = entry;
 188         if (entry)
 189                 entry->irq = irq;
 190         spin_unlock_irqrestore(&desc->lock, flags);
 191         return 0;
 192 }
 193
 194 /**
 195  *      set_irq_chip_data - set irq chip data for an irq
 196  *      @irq:   Interrupt number
 197  *      @data:  Pointer to chip specific data
 198  *
 199  *      Set the hardware irq chip data for an irq
 200  */
 201 int set_irq_chip_data(unsigned int irq, void *data)
 202 {
 203         struct irq_desc *desc;
 204         unsigned long flags;
 205
 206         desc = __irq_to_desc(irq);
 207         if (!desc) {
 208                 printk(KERN_ERR
 209                        "Trying to install chip data for IRQ%d\n", irq);
 210                 return -EINVAL;
 211         }
 212
 213         if (!desc->chip) {
 214                 printk(KERN_ERR "BUG: bad set_irq_chip_data(IRQ#%d)\n", irq);
 215                 return -EINVAL;
 216         }
 217
 218         spin_lock_irqsave(&desc->lock, flags);
 219         desc->chip_data = data;
 220         spin_unlock_irqrestore(&desc->lock, flags);
 221
 222         return 0;
 223 }
 224 EXPORT_SYMBOL(set_irq_chip_data);
 225
 226 /*
 227  * default enable function
 228  */
 229 static void default_enable(unsigned int irq)
 230 {
 231         struct irq_desc *desc;
 232
 233         desc = irq_to_desc(irq);
 234         desc->chip->unmask(irq);
 235         desc->status &= ~IRQ_MASKED;
 236 }
 237
 238 /*
 239  * default disable function
 240  */
 241 static void default_disable(unsigned int irq)
 242 {
 243 }
 244
 245 /*
 246  * default startup function
 247  */
 248 static unsigned int default_startup(unsigned int irq)
 249 {
 250         struct irq_desc *desc;
 251
 252         desc = irq_to_desc(irq);
 253         desc->chip->enable(irq);
 254
 255         return 0;
 256 }
 257
 258 /*
 259  * default shutdown function
 260  */
 261 static void default_shutdown(unsigned int irq)
 262 {
 263         struct irq_desc *desc;
 264
 265         desc = irq_to_desc(irq);
 266         desc->chip->mask(irq);
 267         desc->status |= IRQ_MASKED;
 268 }
 269
 270 /*
 271  * Fixup enable/disable function pointers
 272  */
 273 void irq_chip_set_defaults(struct irq_chip *chip)
 274 {
 275         if (!chip->enable)
 276                 chip->enable = default_enable;
 277         if (!chip->disable)
 278                 chip->disable = default_disable;
 279         if (!chip->startup)
 280                 chip->startup = default_startup;
 281         /*
 282          * We use chip->disable, when the user provided its own. When
 283          * we have default_disable set for chip->disable, then we need
 284          * to use default_shutdown, otherwise the irq line is not
 285          * disabled on free_irq():
 286          */
 287         if (!chip->shutdown)
 288                 chip->shutdown = chip->disable != default_disable ?
 289                         chip->disable : default_shutdown;
 290         if (!chip->name)
 291                 chip->name = chip->typename;
 292         if (!chip->end)
 293                 chip->end = dummy_irq_chip.end;
 294 }
 295
 296 static inline void mask_ack_irq(struct irq_desc *desc, int irq)
 297 {
 298         if (desc->chip->mask_ack)
 299                 desc->chip->mask_ack(irq);
 300         else {
 301                 desc->chip->mask(irq);
 302                 desc->chip->ack(irq);
 303         }
 304 }
 305
 306 /**
 307  *      handle_simple_irq - Simple and software-decoded IRQs.
 308  *      @irq:   the interrupt number
 309  *      @desc:  the interrupt description structure for this irq
 310  *
 311  *      Simple interrupts are either sent from a demultiplexing interrupt
 312  *      handler or come from hardware, where no interrupt hardware control
 313  *      is necessary.
 314  *
 315  *      Note: The caller is expected to handle the ack, clear, mask and
 316  *      unmask issues if necessary.
 317  */
 318 void
 319 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
 320 {
 321         struct irqaction *action;
 322         irqreturn_t action_ret;
 323
 324         spin_lock(&desc->lock);
 325
 326         if (unlikely(desc->status & IRQ_INPROGRESS))
 327                 goto out_unlock;
 328         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 329         kstat_irqs_this_cpu(desc)++;
 330
 331         action = desc->action;
 332         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 333                 goto out_unlock;
 334
 335         desc->status |= IRQ_INPROGRESS;
 336         spin_unlock(&desc->lock);
 337
 338         action_ret = handle_IRQ_event(irq, action);
 339         if (!noirqdebug)
 340                 note_interrupt(irq, desc, action_ret);
 341
 342         spin_lock(&desc->lock);
 343         desc->status &= ~IRQ_INPROGRESS;
 344 out_unlock:
 345         spin_unlock(&desc->lock);
 346 }
 347
 348 /**
 349  *      handle_level_irq - Level type irq handler
 350  *      @irq:   the interrupt number
 351  *      @desc:  the interrupt description structure for this irq
 352  *
 353  *      Level type interrupts are active as long as the hardware line has
 354  *      the active level. This may require to mask the interrupt and unmask
 355  *      it after the associated handler has acknowledged the device, so the
 356  *      interrupt line is back to inactive.
 357  */
 358 void
 359 handle_level_irq(unsigned int irq, struct irq_desc *desc)
 360 {
 361         struct irqaction *action;
 362         irqreturn_t action_ret;
 363
 364         spin_lock(&desc->lock);
 365         mask_ack_irq(desc, irq);
 366
 367         if (unlikely(desc->status & IRQ_INPROGRESS))
 368                 goto out_unlock;
 369         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 370         kstat_irqs_this_cpu(desc)++;
 371
 372         /*
 373          * If its disabled or no action available
 374          * keep it masked and get out of here
 375          */
 376         action = desc->action;
 377         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 378                 goto out_unlock;
 379
 380         desc->status |= IRQ_INPROGRESS;
 381         spin_unlock(&desc->lock);
 382
 383         action_ret = handle_IRQ_event(irq, action);
 384         if (!noirqdebug)
 385                 note_interrupt(irq, desc, action_ret);
 386
 387         spin_lock(&desc->lock);
 388         desc->status &= ~IRQ_INPROGRESS;
 389         if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
 390                 desc->chip->unmask(irq);
 391 out_unlock:
 392         spin_unlock(&desc->lock);
 393 }
 394
 395 /**
 396  *      handle_fasteoi_irq - irq handler for transparent controllers
 397  *      @irq:   the interrupt number
 398  *      @desc:  the interrupt description structure for this irq
 399  *
 400  *      Only a single callback will be issued to the chip: an ->eoi()
 401  *      call when the interrupt has been serviced. This enables support
 402  *      for modern forms of interrupt handlers, which handle the flow
 403  *      details in hardware, transparently.
 404  */
 405 void
 406 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 407 {
 408         struct irqaction *action;
 409         irqreturn_t action_ret;
 410
 411         spin_lock(&desc->lock);
 412
 413         if (unlikely(desc->status & IRQ_INPROGRESS))
 414                 goto out;
 415
 416         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 417         kstat_irqs_this_cpu(desc)++;
 418
 419         /*
 420          * If its disabled or no action available
 421          * then mask it and get out of here:
 422          */
 423         action = desc->action;
 424         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 425                 desc->status |= IRQ_PENDING;
 426                 if (desc->chip->mask)
 427                         desc->chip->mask(irq);
 428                 goto out;
 429         }
 430
 431         desc->status |= IRQ_INPROGRESS;
 432         desc->status &= ~IRQ_PENDING;
 433         spin_unlock(&desc->lock);
 434
 435         action_ret = handle_IRQ_event(irq, action);
 436         if (!noirqdebug)
 437                 note_interrupt(irq, desc, action_ret);
 438
 439         spin_lock(&desc->lock);
 440         desc->status &= ~IRQ_INPROGRESS;
 441 out:
 442         desc->chip->eoi(irq);
 443
 444         spin_unlock(&desc->lock);
 445 }
 446
 447 /**
 448  *      handle_edge_irq - edge type IRQ handler
 449  *      @irq:   the interrupt number
 450  *      @desc:  the interrupt description structure for this irq
 451  *
 452  *      Interrupt occures on the falling and/or rising edge of a hardware
 453  *      signal. The occurence is latched into the irq controller hardware
 454  *      and must be acked in order to be reenabled. After the ack another
 455  *      interrupt can happen on the same source even before the first one
 456  *      is handled by the assosiacted event handler. If this happens it
 457  *      might be necessary to disable (mask) the interrupt depending on the
 458  *      controller hardware. This requires to reenable the interrupt inside
 459  *      of the loop which handles the interrupts which have arrived while
 460  *      the handler was running. If all pending interrupts are handled, the
 461  *      loop is left.
 462  */
 463 void
 464 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
 465 {
 466         spin_lock(&desc->lock);
 467
 468         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 469
 470         /*
 471          * If we're currently running this IRQ, or its disabled,
 472          * we shouldn't process the IRQ. Mark it pending, handle
 473          * the necessary masking and go out
 474          */
 475         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 476                     !desc->action)) {
 477                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 478                 mask_ack_irq(desc, irq);
 479                 goto out_unlock;
 480         }
 481
 482         kstat_irqs_this_cpu(desc)++;
 483
 484         /* Start handling the irq */
 485         desc->chip->ack(irq);
 486
 487         /* Mark the IRQ currently in progress.*/
 488         desc->status |= IRQ_INPROGRESS;
 489
 490         do {
 491                 struct irqaction *action = desc->action;
 492                 irqreturn_t action_ret;
 493
 494                 if (unlikely(!action)) {
 495                         desc->chip->mask(irq);
 496                         goto out_unlock;
 497                 }
 498
 499                 /*
 500                  * When another irq arrived while we were handling
 501                  * one, we could have masked the irq.
 502                  * Renable it, if it was not disabled in meantime.
 503                  */
 504                 if (unlikely((desc->status &
 505                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 506                               (IRQ_PENDING | IRQ_MASKED))) {
 507                         desc->chip->unmask(irq);
 508                         desc->status &= ~IRQ_MASKED;
 509                 }
 510
 511                 desc->status &= ~IRQ_PENDING;
 512                 spin_unlock(&desc->lock);
 513                 action_ret = handle_IRQ_event(irq, action);
 514                 if (!noirqdebug)
 515                         note_interrupt(irq, desc, action_ret);
 516                 spin_lock(&desc->lock);
 517
 518         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 519
 520         desc->status &= ~IRQ_INPROGRESS;
 521 out_unlock:
 522         spin_unlock(&desc->lock);
 523 }
 524
 525 /**
 526  *      handle_percpu_IRQ - Per CPU local irq handler
 527  *      @irq:   the interrupt number
 528  *      @desc:  the interrupt description structure for this irq
 529  *
 530  *      Per CPU interrupts on SMP machines without locking requirements
 531  */
 532 void
 533 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
 534 {
 535         irqreturn_t action_ret;
 536
 537         kstat_irqs_this_cpu(desc)++;
 538
 539         if (desc->chip->ack)
 540                 desc->chip->ack(irq);
 541
 542         action_ret = handle_IRQ_event(irq, desc->action);
 543         if (!noirqdebug)
 544                 note_interrupt(irq, desc, action_ret);
 545
 546         if (desc->chip->eoi)
 547                 desc->chip->eoi(irq);
 548 }
 549
 550 void
 551 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
 552                   const char *name)
 553 {
 554         struct irq_desc *desc;
 555         unsigned long flags;
 556
 557         desc = __irq_to_desc(irq);
 558         if (!desc) {
 559                 printk(KERN_ERR
 560                        "Trying to install type control for IRQ%d\n", irq);
 561                 return;
 562         }
 563
 564         if (!handle)
 565                 handle = handle_bad_irq;
 566         else if (desc->chip == &no_irq_chip) {
 567                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 568                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
 569                 /*
 570                  * Some ARM implementations install a handler for really dumb
 571                  * interrupt hardware without setting an irq_chip. This worked
 572                  * with the ARM no_irq_chip but the check in setup_irq would
 573                  * prevent us to setup the interrupt at all. Switch it to
 574                  * dummy_irq_chip for easy transition.
 575                  */
 576                 desc->chip = &dummy_irq_chip;
 577         }
 578
 579         spin_lock_irqsave(&desc->lock, flags);
 580
 581         /* Uninstall? */
 582         if (handle == handle_bad_irq) {
 583                 if (desc->chip != &no_irq_chip)
 584                         mask_ack_irq(desc, irq);
 585                 desc->status |= IRQ_DISABLED;
 586                 desc->depth = 1;
 587         }
 588         desc->handle_irq = handle;
 589         desc->name = name;
 590
 591         if (handle != handle_bad_irq && is_chained) {
 592                 desc->status &= ~IRQ_DISABLED;
 593                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 594                 desc->depth = 0;
 595                 desc->chip->startup(irq);
 596         }
 597         spin_unlock_irqrestore(&desc->lock, flags);
 598 }
 599
 600 void
 601 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 602                          irq_flow_handler_t handle)
 603 {
 604         set_irq_chip(irq, chip);
 605         __set_irq_handler(irq, handle, 0, NULL);
 606 }
 607
 608 void
 609 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
 610                               irq_flow_handler_t handle, const char *name)
 611 {
 612         set_irq_chip(irq, chip);
 613         __set_irq_handler(irq, handle, 0, name);
 614 }
 615
 616 void __init set_irq_noprobe(unsigned int irq)
 617 {
 618         struct irq_desc *desc;
 619         unsigned long flags;
 620
 621         desc = __irq_to_desc(irq);
 622         if (!desc) {
 623                 printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);
 624
 625                 return;
 626         }
 627
 628         spin_lock_irqsave(&desc->lock, flags);
 629         desc->status |= IRQ_NOPROBE;
 630         spin_unlock_irqrestore(&desc->lock, flags);
 631 }
 632
 633 void __init set_irq_probe(unsigned int irq)
 634 {
 635         struct irq_desc *desc;
 636         unsigned long flags;
 637
 638         desc = __irq_to_desc(irq);
 639         if (!desc) {
 640                 printk(KERN_ERR "Trying to mark IRQ%d probeable\n", irq);
 641
 642                 return;
 643         }
 644
 645         spin_lock_irqsave(&desc->lock, flags);
 646         desc->status &= ~IRQ_NOPROBE;
 647         spin_unlock_irqrestore(&desc->lock, flags);
 648 }