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