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->handler_data = NULL;
  43         desc->chip_data = NULL;
  44         desc->action = NULL;
  45         desc->irq_count = 0;
  46         desc->irqs_unhandled = 0;
  47 #ifdef CONFIG_SMP
  48         desc->affinity = CPU_MASK_ALL;
  49 #endif
  50         spin_unlock_irqrestore(&desc->lock, flags);
  51 }
  52
  53 /**
  54  *      dynamic_irq_cleanup - cleanup a dynamically allocated irq
  55  *      @irq:   irq number to initialize
  56  */
  57 void dynamic_irq_cleanup(unsigned int irq)
  58 {
  59         struct irq_desc *desc;
  60         unsigned long flags;
  61
  62         if (irq >= NR_IRQS) {
  63                 printk(KERN_ERR "Trying to cleanup invalid IRQ%d\n", irq);
  64                 WARN_ON(1);
  65                 return;
  66         }
  67
  68         desc = irq_desc + irq;
  69         spin_lock_irqsave(&desc->lock, flags);
  70         if (desc->action) {
  71                 spin_unlock_irqrestore(&desc->lock, flags);
  72                 printk(KERN_ERR "Destroying IRQ%d without calling free_irq\n",
  73                         irq);
  74                 WARN_ON(1);
  75                 return;
  76         }
  77         desc->handle_irq = handle_bad_irq;
  78         desc->chip = &no_irq_chip;
  79         spin_unlock_irqrestore(&desc->lock, flags);
  80 }
  81
  82
  83 /**
  84  *      set_irq_chip - set the irq chip for an irq
  85  *      @irq:   irq number
  86  *      @chip:  pointer to irq chip description structure
  87  */
  88 int set_irq_chip(unsigned int irq, struct irq_chip *chip)
  89 {
  90         struct irq_desc *desc;
  91         unsigned long flags;
  92
  93         if (irq >= NR_IRQS) {
  94                 printk(KERN_ERR "Trying to install chip for IRQ%d\n", irq);
  95                 WARN_ON(1);
  96                 return -EINVAL;
  97         }
  98
  99         if (!chip)
 100                 chip = &no_irq_chip;
 101
 102         desc = irq_desc + irq;
 103         spin_lock_irqsave(&desc->lock, flags);
 104         irq_chip_set_defaults(chip);
 105         desc->chip = chip;
 106         spin_unlock_irqrestore(&desc->lock, flags);
 107
 108         return 0;
 109 }
 110 EXPORT_SYMBOL(set_irq_chip);
 111
 112 /**
 113  *      set_irq_type - set the irq type for an irq
 114  *      @irq:   irq number
 115  *      @type:  interrupt type - see include/linux/interrupt.h
 116  */
 117 int set_irq_type(unsigned int irq, unsigned int type)
 118 {
 119         struct irq_desc *desc;
 120         unsigned long flags;
 121         int ret = -ENXIO;
 122
 123         if (irq >= NR_IRQS) {
 124                 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
 125                 return -ENODEV;
 126         }
 127
 128         desc = irq_desc + irq;
 129         if (desc->chip->set_type) {
 130                 spin_lock_irqsave(&desc->lock, flags);
 131                 ret = desc->chip->set_type(irq, type);
 132                 spin_unlock_irqrestore(&desc->lock, flags);
 133         }
 134         return ret;
 135 }
 136 EXPORT_SYMBOL(set_irq_type);
 137
 138 /**
 139  *      set_irq_data - set irq type data for an irq
 140  *      @irq:   Interrupt number
 141  *      @data:  Pointer to interrupt specific data
 142  *
 143  *      Set the hardware irq controller data for an irq
 144  */
 145 int set_irq_data(unsigned int irq, void *data)
 146 {
 147         struct irq_desc *desc;
 148         unsigned long flags;
 149
 150         if (irq >= NR_IRQS) {
 151                 printk(KERN_ERR
 152                        "Trying to install controller data for IRQ%d\n", irq);
 153                 return -EINVAL;
 154         }
 155
 156         desc = irq_desc + irq;
 157         spin_lock_irqsave(&desc->lock, flags);
 158         desc->handler_data = data;
 159         spin_unlock_irqrestore(&desc->lock, flags);
 160         return 0;
 161 }
 162 EXPORT_SYMBOL(set_irq_data);
 163
 164 /**
 165  *      set_irq_chip_data - set irq chip data for an irq
 166  *      @irq:   Interrupt number
 167  *      @data:  Pointer to chip specific data
 168  *
 169  *      Set the hardware irq chip data for an irq
 170  */
 171 int set_irq_chip_data(unsigned int irq, void *data)
 172 {
 173         struct irq_desc *desc = irq_desc + irq;
 174         unsigned long flags;
 175
 176         if (irq >= NR_IRQS || !desc->chip) {
 177                 printk(KERN_ERR "BUG: bad set_irq_chip_data(IRQ#%d)\n", irq);
 178                 return -EINVAL;
 179         }
 180
 181         spin_lock_irqsave(&desc->lock, flags);
 182         desc->chip_data = data;
 183         spin_unlock_irqrestore(&desc->lock, flags);
 184
 185         return 0;
 186 }
 187 EXPORT_SYMBOL(set_irq_chip_data);
 188
 189 /*
 190  * default enable function
 191  */
 192 static void default_enable(unsigned int irq)
 193 {
 194         struct irq_desc *desc = irq_desc + irq;
 195
 196         desc->chip->unmask(irq);
 197         desc->status &= ~IRQ_MASKED;
 198 }
 199
 200 /*
 201  * default disable function
 202  */
 203 static void default_disable(unsigned int irq)
 204 {
 205         struct irq_desc *desc = irq_desc + irq;
 206
 207         if (!(desc->status & IRQ_DELAYED_DISABLE))
 208                 desc->chip->mask(irq);
 209 }
 210
 211 /*
 212  * default startup function
 213  */
 214 static unsigned int default_startup(unsigned int irq)
 215 {
 216         irq_desc[irq].chip->enable(irq);
 217
 218         return 0;
 219 }
 220
 221 /*
 222  * Fixup enable/disable function pointers
 223  */
 224 void irq_chip_set_defaults(struct irq_chip *chip)
 225 {
 226         if (!chip->enable)
 227                 chip->enable = default_enable;
 228         if (!chip->disable)
 229                 chip->disable = default_disable;
 230         if (!chip->startup)
 231                 chip->startup = default_startup;
 232         if (!chip->shutdown)
 233                 chip->shutdown = chip->disable;
 234         if (!chip->name)
 235                 chip->name = chip->typename;
 236 }
 237
 238 static inline void mask_ack_irq(struct irq_desc *desc, int irq)
 239 {
 240         if (desc->chip->mask_ack)
 241                 desc->chip->mask_ack(irq);
 242         else {
 243                 desc->chip->mask(irq);
 244                 desc->chip->ack(irq);
 245         }
 246 }
 247
 248 /**
 249  *      handle_simple_irq - Simple and software-decoded IRQs.
 250  *      @irq:   the interrupt number
 251  *      @desc:  the interrupt description structure for this irq
 252  *
 253  *      Simple interrupts are either sent from a demultiplexing interrupt
 254  *      handler or come from hardware, where no interrupt hardware control
 255  *      is necessary.
 256  *
 257  *      Note: The caller is expected to handle the ack, clear, mask and
 258  *      unmask issues if necessary.
 259  */
 260 void fastcall
 261 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
 262 {
 263         struct irqaction *action;
 264         irqreturn_t action_ret;
 265         const unsigned int cpu = smp_processor_id();
 266
 267         spin_lock(&desc->lock);
 268
 269         if (unlikely(desc->status & IRQ_INPROGRESS))
 270                 goto out_unlock;
 271         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 272         kstat_cpu(cpu).irqs[irq]++;
 273
 274         action = desc->action;
 275         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 276                 goto out_unlock;
 277
 278         desc->status |= IRQ_INPROGRESS;
 279         spin_unlock(&desc->lock);
 280
 281         action_ret = handle_IRQ_event(irq, action);
 282         if (!noirqdebug)
 283                 note_interrupt(irq, desc, action_ret);
 284
 285         spin_lock(&desc->lock);
 286         desc->status &= ~IRQ_INPROGRESS;
 287 out_unlock:
 288         spin_unlock(&desc->lock);
 289 }
 290
 291 /**
 292  *      handle_level_irq - Level type irq handler
 293  *      @irq:   the interrupt number
 294  *      @desc:  the interrupt description structure for this irq
 295  *
 296  *      Level type interrupts are active as long as the hardware line has
 297  *      the active level. This may require to mask the interrupt and unmask
 298  *      it after the associated handler has acknowledged the device, so the
 299  *      interrupt line is back to inactive.
 300  */
 301 void fastcall
 302 handle_level_irq(unsigned int irq, struct irq_desc *desc)
 303 {
 304         unsigned int cpu = smp_processor_id();
 305         struct irqaction *action;
 306         irqreturn_t action_ret;
 307
 308         spin_lock(&desc->lock);
 309         mask_ack_irq(desc, irq);
 310
 311         if (unlikely(desc->status & IRQ_INPROGRESS))
 312                 goto out_unlock;
 313         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 314         kstat_cpu(cpu).irqs[irq]++;
 315
 316         /*
 317          * If its disabled or no action available
 318          * keep it masked and get out of here
 319          */
 320         action = desc->action;
 321         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 322                 desc->status |= IRQ_PENDING;
 323                 goto out_unlock;
 324         }
 325
 326         desc->status |= IRQ_INPROGRESS;
 327         desc->status &= ~IRQ_PENDING;
 328         spin_unlock(&desc->lock);
 329
 330         action_ret = handle_IRQ_event(irq, action);
 331         if (!noirqdebug)
 332                 note_interrupt(irq, desc, action_ret);
 333
 334         spin_lock(&desc->lock);
 335         desc->status &= ~IRQ_INPROGRESS;
 336         if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
 337                 desc->chip->unmask(irq);
 338 out_unlock:
 339         spin_unlock(&desc->lock);
 340 }
 341
 342 /**
 343  *      handle_fasteoi_irq - irq handler for transparent controllers
 344  *      @irq:   the interrupt number
 345  *      @desc:  the interrupt description structure for this irq
 346  *
 347  *      Only a single callback will be issued to the chip: an ->eoi()
 348  *      call when the interrupt has been serviced. This enables support
 349  *      for modern forms of interrupt handlers, which handle the flow
 350  *      details in hardware, transparently.
 351  */
 352 void fastcall
 353 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 354 {
 355         unsigned int cpu = smp_processor_id();
 356         struct irqaction *action;
 357         irqreturn_t action_ret;
 358
 359         spin_lock(&desc->lock);
 360
 361         if (unlikely(desc->status & IRQ_INPROGRESS))
 362                 goto out;
 363
 364         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 365         kstat_cpu(cpu).irqs[irq]++;
 366
 367         /*
 368          * If its disabled or no action available
 369          * keep it masked and get out of here
 370          */
 371         action = desc->action;
 372         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 373                 desc->status |= IRQ_PENDING;
 374                 goto out;
 375         }
 376
 377         desc->status |= IRQ_INPROGRESS;
 378         desc->status &= ~IRQ_PENDING;
 379         spin_unlock(&desc->lock);
 380
 381         action_ret = handle_IRQ_event(irq, action);
 382         if (!noirqdebug)
 383                 note_interrupt(irq, desc, action_ret);
 384
 385         spin_lock(&desc->lock);
 386         desc->status &= ~IRQ_INPROGRESS;
 387 out:
 388         desc->chip->eoi(irq);
 389
 390         spin_unlock(&desc->lock);
 391 }
 392
 393 /**
 394  *      handle_edge_irq - edge type IRQ handler
 395  *      @irq:   the interrupt number
 396  *      @desc:  the interrupt description structure for this irq
 397  *
 398  *      Interrupt occures on the falling and/or rising edge of a hardware
 399  *      signal. The occurence is latched into the irq controller hardware
 400  *      and must be acked in order to be reenabled. After the ack another
 401  *      interrupt can happen on the same source even before the first one
 402  *      is handled by the assosiacted event handler. If this happens it
 403  *      might be necessary to disable (mask) the interrupt depending on the
 404  *      controller hardware. This requires to reenable the interrupt inside
 405  *      of the loop which handles the interrupts which have arrived while
 406  *      the handler was running. If all pending interrupts are handled, the
 407  *      loop is left.
 408  */
 409 void fastcall
 410 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
 411 {
 412         const unsigned int cpu = smp_processor_id();
 413
 414         spin_lock(&desc->lock);
 415
 416         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 417
 418         /*
 419          * If we're currently running this IRQ, or its disabled,
 420          * we shouldn't process the IRQ. Mark it pending, handle
 421          * the necessary masking and go out
 422          */
 423         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 424                     !desc->action)) {
 425                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 426                 mask_ack_irq(desc, irq);
 427                 goto out_unlock;
 428         }
 429
 430         kstat_cpu(cpu).irqs[irq]++;
 431
 432         /* Start handling the irq */
 433         desc->chip->ack(irq);
 434
 435         /* Mark the IRQ currently in progress.*/
 436         desc->status |= IRQ_INPROGRESS;
 437
 438         do {
 439                 struct irqaction *action = desc->action;
 440                 irqreturn_t action_ret;
 441
 442                 if (unlikely(!action)) {
 443                         desc->chip->mask(irq);
 444                         goto out_unlock;
 445                 }
 446
 447                 /*
 448                  * When another irq arrived while we were handling
 449                  * one, we could have masked the irq.
 450                  * Renable it, if it was not disabled in meantime.
 451                  */
 452                 if (unlikely((desc->status &
 453                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 454                               (IRQ_PENDING | IRQ_MASKED))) {
 455                         desc->chip->unmask(irq);
 456                         desc->status &= ~IRQ_MASKED;
 457                 }
 458
 459                 desc->status &= ~IRQ_PENDING;
 460                 spin_unlock(&desc->lock);
 461                 action_ret = handle_IRQ_event(irq, action);
 462                 if (!noirqdebug)
 463                         note_interrupt(irq, desc, action_ret);
 464                 spin_lock(&desc->lock);
 465
 466         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 467
 468         desc->status &= ~IRQ_INPROGRESS;
 469 out_unlock:
 470         spin_unlock(&desc->lock);
 471 }
 472
 473 #ifdef CONFIG_SMP
 474 /**
 475  *      handle_percpu_IRQ - Per CPU local irq handler
 476  *      @irq:   the interrupt number
 477  *      @desc:  the interrupt description structure for this irq
 478  *
 479  *      Per CPU interrupts on SMP machines without locking requirements
 480  */
 481 void fastcall
 482 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
 483 {
 484         irqreturn_t action_ret;
 485
 486         kstat_this_cpu.irqs[irq]++;
 487
 488         if (desc->chip->ack)
 489                 desc->chip->ack(irq);
 490
 491         action_ret = handle_IRQ_event(irq, desc->action);
 492         if (!noirqdebug)
 493                 note_interrupt(irq, desc, action_ret);
 494
 495         if (desc->chip->eoi)
 496                 desc->chip->eoi(irq);
 497 }
 498
 499 #endif /* CONFIG_SMP */
 500
 501 void
 502 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained)
 503 {
 504         struct irq_desc *desc;
 505         unsigned long flags;
 506
 507         if (irq >= NR_IRQS) {
 508                 printk(KERN_ERR
 509                        "Trying to install type control for IRQ%d\n", irq);
 510                 return;
 511         }
 512
 513         desc = irq_desc + irq;
 514
 515         if (!handle)
 516                 handle = handle_bad_irq;
 517
 518         if (desc->chip == &no_irq_chip) {
 519                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 520                        "for IRQ%d\n", is_chained ? "chained " : " ", irq);
 521                 /*
 522                  * Some ARM implementations install a handler for really dumb
 523                  * interrupt hardware without setting an irq_chip. This worked
 524                  * with the ARM no_irq_chip but the check in setup_irq would
 525                  * prevent us to setup the interrupt at all. Switch it to
 526                  * dummy_irq_chip for easy transition.
 527                  */
 528                 desc->chip = &dummy_irq_chip;
 529         }
 530
 531         spin_lock_irqsave(&desc->lock, flags);
 532
 533         /* Uninstall? */
 534         if (handle == handle_bad_irq) {
 535                 if (desc->chip != &no_irq_chip) {
 536                         desc->chip->mask(irq);
 537                         desc->chip->ack(irq);
 538                 }
 539                 desc->status |= IRQ_DISABLED;
 540                 desc->depth = 1;
 541         }
 542         desc->handle_irq = handle;
 543
 544         if (handle != handle_bad_irq && is_chained) {
 545                 desc->status &= ~IRQ_DISABLED;
 546                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 547                 desc->depth = 0;
 548                 desc->chip->unmask(irq);
 549         }
 550         spin_unlock_irqrestore(&desc->lock, flags);
 551 }
 552
 553 void
 554 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 555                          irq_flow_handler_t handle)
 556 {
 557         set_irq_chip(irq, chip);
 558         __set_irq_handler(irq, handle, 0);
 559 }
 560
 561 /*
 562  * Get a descriptive string for the highlevel handler, for
 563  * /proc/interrupts output:
 564  */
 565 const char *
 566 handle_irq_name(irq_flow_handler_t handle)
 567 {
 568         if (handle == handle_level_irq)
 569                 return "level  ";
 570         if (handle == handle_fasteoi_irq)
 571                 return "fasteoi";
 572         if (handle == handle_edge_irq)
 573                 return "edge   ";
 574         if (handle == handle_simple_irq)
 575                 return "simple ";
 576 #ifdef CONFIG_SMP
 577         if (handle == handle_percpu_irq)
 578                 return "percpu ";
 579 #endif
 580         if (handle == handle_bad_irq)
 581                 return "bad    ";
 582
 583         return NULL;
 584 }