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