err.no Git - linux-2.6/blob - 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  *      @regs:  pointer to a register structure
 253  *
 254  *      Simple interrupts are either sent from a demultiplexing interrupt
 255  *      handler or come from hardware, where no interrupt hardware control
 256  *      is necessary.
 257  *
 258  *      Note: The caller is expected to handle the ack, clear, mask and
 259  *      unmask issues if necessary.
 260  */
 261 void fastcall
 262 handle_simple_irq(unsigned int irq, struct irq_desc *desc, struct pt_regs *regs)
 263 {
 264         struct irqaction *action;
 265         irqreturn_t action_ret;
 266         const unsigned int cpu = smp_processor_id();
 267
 268         spin_lock(&desc->lock);
 269
 270         if (unlikely(desc->status & IRQ_INPROGRESS))
 271                 goto out_unlock;
 272         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 273         kstat_cpu(cpu).irqs[irq]++;
 274
 275         action = desc->action;
 276         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 277                 goto out_unlock;
 278
 279         desc->status |= IRQ_INPROGRESS;
 280         spin_unlock(&desc->lock);
 281
 282         action_ret = handle_IRQ_event(irq, regs, action);
 283         if (!noirqdebug)
 284                 note_interrupt(irq, desc, action_ret, regs);
 285
 286         spin_lock(&desc->lock);
 287         desc->status &= ~IRQ_INPROGRESS;
 288 out_unlock:
 289         spin_unlock(&desc->lock);
 290 }
 291
 292 /**
 293  *      handle_level_irq - Level type irq handler
 294  *      @irq:   the interrupt number
 295  *      @desc:  the interrupt description structure for this irq
 296  *      @regs:  pointer to a register structure
 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, struct pt_regs *regs)
 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, regs, action);
 333         if (!noirqdebug)
 334                 note_interrupt(irq, desc, action_ret, regs);
 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  *      @regs:  pointer to a register structure
 349  *
 350  *      Only a single callback will be issued to the chip: an ->eoi()
 351  *      call when the interrupt has been serviced. This enables support
 352  *      for modern forms of interrupt handlers, which handle the flow
 353  *      details in hardware, transparently.
 354  */
 355 void fastcall
 356 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc,
 357                    struct pt_regs *regs)
 358 {
 359         unsigned int cpu = smp_processor_id();
 360         struct irqaction *action;
 361         irqreturn_t action_ret;
 362
 363         spin_lock(&desc->lock);
 364
 365         if (unlikely(desc->status & IRQ_INPROGRESS))
 366                 goto out;
 367
 368         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 369         kstat_cpu(cpu).irqs[irq]++;
 370
 371         /*
 372          * If its disabled or no action available
 373          * keep it masked and get out of here
 374          */
 375         action = desc->action;
 376         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 377                 desc->status |= IRQ_PENDING;
 378                 goto out;
 379         }
 380
 381         desc->status |= IRQ_INPROGRESS;
 382         desc->status &= ~IRQ_PENDING;
 383         spin_unlock(&desc->lock);
 384
 385         action_ret = handle_IRQ_event(irq, regs, action);
 386         if (!noirqdebug)
 387                 note_interrupt(irq, desc, action_ret, regs);
 388
 389         spin_lock(&desc->lock);
 390         desc->status &= ~IRQ_INPROGRESS;
 391 out:
 392         desc->chip->eoi(irq);
 393
 394         spin_unlock(&desc->lock);
 395 }
 396
 397 /**
 398  *      handle_edge_irq - edge type IRQ handler
 399  *      @irq:   the interrupt number
 400  *      @desc:  the interrupt description structure for this irq
 401  *      @regs:  pointer to a register structure
 402  *
 403  *      Interrupt occures on the falling and/or rising edge of a hardware
 404  *      signal. The occurence is latched into the irq controller hardware
 405  *      and must be acked in order to be reenabled. After the ack another
 406  *      interrupt can happen on the same source even before the first one
 407  *      is handled by the assosiacted event handler. If this happens it
 408  *      might be necessary to disable (mask) the interrupt depending on the
 409  *      controller hardware. This requires to reenable the interrupt inside
 410  *      of the loop which handles the interrupts which have arrived while
 411  *      the handler was running. If all pending interrupts are handled, the
 412  *      loop is left.
 413  */
 414 void fastcall
 415 handle_edge_irq(unsigned int irq, struct irq_desc *desc, struct pt_regs *regs)
 416 {
 417         const unsigned int cpu = smp_processor_id();
 418
 419         spin_lock(&desc->lock);
 420
 421         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 422
 423         /*
 424          * If we're currently running this IRQ, or its disabled,
 425          * we shouldn't process the IRQ. Mark it pending, handle
 426          * the necessary masking and go out
 427          */
 428         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 429                     !desc->action)) {
 430                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 431                 mask_ack_irq(desc, irq);
 432                 goto out_unlock;
 433         }
 434
 435         kstat_cpu(cpu).irqs[irq]++;
 436
 437         /* Start handling the irq */
 438         desc->chip->ack(irq);
 439
 440         /* Mark the IRQ currently in progress.*/
 441         desc->status |= IRQ_INPROGRESS;
 442
 443         do {
 444                 struct irqaction *action = desc->action;
 445                 irqreturn_t action_ret;
 446
 447                 if (unlikely(!action)) {
 448                         desc->chip->mask(irq);
 449                         goto out_unlock;
 450                 }
 451
 452                 /*
 453                  * When another irq arrived while we were handling
 454                  * one, we could have masked the irq.
 455                  * Renable it, if it was not disabled in meantime.
 456                  */
 457                 if (unlikely((desc->status &
 458                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 459                               (IRQ_PENDING | IRQ_MASKED))) {
 460                         desc->chip->unmask(irq);
 461                         desc->status &= ~IRQ_MASKED;
 462                 }
 463
 464                 desc->status &= ~IRQ_PENDING;
 465                 spin_unlock(&desc->lock);
 466                 action_ret = handle_IRQ_event(irq, regs, action);
 467                 if (!noirqdebug)
 468                         note_interrupt(irq, desc, action_ret, regs);
 469                 spin_lock(&desc->lock);
 470
 471         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 472
 473         desc->status &= ~IRQ_INPROGRESS;
 474 out_unlock:
 475         spin_unlock(&desc->lock);
 476 }
 477
 478 #ifdef CONFIG_SMP
 479 /**
 480  *      handle_percpu_IRQ - Per CPU local irq handler
 481  *      @irq:   the interrupt number
 482  *      @desc:  the interrupt description structure for this irq
 483  *      @regs:  pointer to a register structure
 484  *
 485  *      Per CPU interrupts on SMP machines without locking requirements
 486  */
 487 void fastcall
 488 handle_percpu_irq(unsigned int irq, struct irq_desc *desc, struct pt_regs *regs)
 489 {
 490         irqreturn_t action_ret;
 491
 492         kstat_this_cpu.irqs[irq]++;
 493
 494         if (desc->chip->ack)
 495                 desc->chip->ack(irq);
 496
 497         action_ret = handle_IRQ_event(irq, regs, desc->action);
 498         if (!noirqdebug)
 499                 note_interrupt(irq, desc, action_ret, regs);
 500
 501         if (desc->chip->eoi)
 502                 desc->chip->eoi(irq);
 503 }
 504
 505 #endif /* CONFIG_SMP */
 506
 507 void
 508 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained)
 509 {
 510         struct irq_desc *desc;
 511         unsigned long flags;
 512
 513         if (irq >= NR_IRQS) {
 514                 printk(KERN_ERR
 515                        "Trying to install type control for IRQ%d\n", irq);
 516                 return;
 517         }
 518
 519         desc = irq_desc + irq;
 520
 521         if (!handle)
 522                 handle = handle_bad_irq;
 523
 524         if (desc->chip == &no_irq_chip) {
 525                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 526                        "for IRQ%d\n", is_chained ? "chained " : " ", irq);
 527                 /*
 528                  * Some ARM implementations install a handler for really dumb
 529                  * interrupt hardware without setting an irq_chip. This worked
 530                  * with the ARM no_irq_chip but the check in setup_irq would
 531                  * prevent us to setup the interrupt at all. Switch it to
 532                  * dummy_irq_chip for easy transition.
 533                  */
 534                 desc->chip = &dummy_irq_chip;
 535         }
 536
 537         spin_lock_irqsave(&desc->lock, flags);
 538
 539         /* Uninstall? */
 540         if (handle == handle_bad_irq) {
 541                 if (desc->chip != &no_irq_chip) {
 542                         desc->chip->mask(irq);
 543                         desc->chip->ack(irq);
 544                 }
 545                 desc->status |= IRQ_DISABLED;
 546                 desc->depth = 1;
 547         }
 548         desc->handle_irq = handle;
 549
 550         if (handle != handle_bad_irq && is_chained) {
 551                 desc->status &= ~IRQ_DISABLED;
 552                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 553                 desc->depth = 0;
 554                 desc->chip->unmask(irq);
 555         }
 556         spin_unlock_irqrestore(&desc->lock, flags);
 557 }
 558
 559 void
 560 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 561                          irq_flow_handler_t handle)
 562 {
 563         set_irq_chip(irq, chip);
 564         __set_irq_handler(irq, handle, 0);
 565 }
 566
 567 /*
 568  * Get a descriptive string for the highlevel handler, for
 569  * /proc/interrupts output:
 570  */
 571 const char *
 572 handle_irq_name(irq_flow_handler_t handle)
 573 {
 574         if (handle == handle_level_irq)
 575                 return "level  ";
 576         if (handle == handle_fasteoi_irq)
 577                 return "fasteoi";
 578         if (handle == handle_edge_irq)
 579                 return "edge   ";
 580         if (handle == handle_simple_irq)
 581                 return "simple ";
 582 #ifdef CONFIG_SMP
 583         if (handle == handle_percpu_irq)
 584                 return "percpu ";
 585 #endif
 586         if (handle == handle_bad_irq)
 587                 return "bad    ";
 588
 589         return NULL;
 590 }