kernel/irq/handle.c

   1 /*
   2  * linux/kernel/irq/handle.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.
   8  *
   9  * Detailed information is available in Documentation/DocBook/genericirq
  10  *
  11  */
  12
  13 #include <linux/irq.h>
  14 #include <linux/module.h>
  15 #include <linux/random.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/kernel_stat.h>
  18
  19 #include "internals.h"
  20
  21 #ifdef CONFIG_TRACE_IRQFLAGS
  22
  23 /*
  24  * lockdep: we want to handle all irq_desc locks as a single lock-class:
  25  */
  26 static struct lock_class_key irq_desc_lock_class;
  27 #endif
  28
  29 /**
  30  * handle_bad_irq - handle spurious and unhandled irqs
  31  * @irq:       the interrupt number
  32  * @desc:      description of the interrupt
  33  *
  34  * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
  35  */
  36 void
  37 handle_bad_irq(unsigned int irq, struct irq_desc *desc)
  38 {
  39         print_irq_desc(irq, desc);
  40         kstat_irqs_this_cpu(desc)++;
  41         ack_bad_irq(irq);
  42 }
  43
  44 /*
  45  * Linux has a controller-independent interrupt architecture.
  46  * Every controller has a 'controller-template', that is used
  47  * by the main code to do the right thing. Each driver-visible
  48  * interrupt source is transparently wired to the appropriate
  49  * controller. Thus drivers need not be aware of the
  50  * interrupt-controller.
  51  *
  52  * The code is designed to be easily extended with new/different
  53  * interrupt controllers, without having to do assembly magic or
  54  * having to touch the generic code.
  55  *
  56  * Controller mappings for all interrupt sources:
  57  */
  58 int nr_irqs = NR_IRQS;
  59 EXPORT_SYMBOL_GPL(nr_irqs);
  60
  61 #ifdef CONFIG_HAVE_DYN_ARRAY
  62 static struct irq_desc irq_desc_init = {
  63         .irq = -1U,
  64         .status = IRQ_DISABLED,
  65         .chip = &no_irq_chip,
  66         .handle_irq = handle_bad_irq,
  67         .depth = 1,
  68         .lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
  69 #ifdef CONFIG_SMP
  70         .affinity = CPU_MASK_ALL
  71 #endif
  72 };
  73
  74
  75 static void init_one_irq_desc(struct irq_desc *desc)
  76 {
  77         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
  78 #ifdef CONFIG_TRACE_IRQFLAGS
  79         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
  80 #endif
  81 }
  82
  83 extern int after_bootmem;
  84 extern void *__alloc_bootmem_nopanic(unsigned long size,
  85                              unsigned long align,
  86                              unsigned long goal);
  87
  88 static void init_kstat_irqs(struct irq_desc *desc, int nr_desc, int nr)
  89 {
  90         unsigned long bytes, total_bytes;
  91         char *ptr;
  92         int i;
  93         unsigned long phys;
  94
  95         /* Compute how many bytes we need per irq and allocate them */
  96         bytes = nr * sizeof(unsigned int);
  97         total_bytes = bytes * nr_desc;
  98         if (after_bootmem)
  99                 ptr = kzalloc(total_bytes, GFP_ATOMIC);
 100         else
 101                 ptr = __alloc_bootmem_nopanic(total_bytes, PAGE_SIZE, 0);
 102
 103         if (!ptr)
 104                 panic(" can not allocate kstat_irqs\n");
 105
 106         phys = __pa(ptr);
 107         printk(KERN_DEBUG "kstat_irqs ==> [%#lx - %#lx]\n", phys, phys + total_bytes);
 108
 109         for (i = 0; i < nr_desc; i++) {
 110                 desc[i].kstat_irqs = (unsigned int *)ptr;
 111                 ptr += bytes;
 112         }
 113 }
 114
 115 #ifdef CONFIG_HAVE_SPARSE_IRQ
 116 static struct irq_desc *sparse_irqs_free;
 117 struct irq_desc *sparse_irqs;
 118 #endif
 119
 120 static void __init init_work(void *data)
 121 {
 122         struct dyn_array *da = data;
 123         int i;
 124         struct  irq_desc *desc;
 125
 126         desc = *da->name;
 127
 128         for (i = 0; i < *da->nr; i++) {
 129                 init_one_irq_desc(&desc[i]);
 130 #ifndef CONFIG_HAVE_SPARSE_IRQ
 131                 desc[i].irq = i;
 132 #endif
 133         }
 134
 135         /* init kstat_irqs, nr_cpu_ids is ready already */
 136         init_kstat_irqs(desc, *da->nr, nr_cpu_ids);
 137
 138 #ifdef CONFIG_HAVE_SPARSE_IRQ
 139         for (i = 1; i < *da->nr; i++)
 140                 desc[i-1].next = &desc[i];
 141
 142         sparse_irqs_free = sparse_irqs;
 143         sparse_irqs = NULL;
 144 #endif
 145 }
 146
 147 #ifdef CONFIG_HAVE_SPARSE_IRQ
 148 static int nr_irq_desc = 32;
 149
 150 static int __init parse_nr_irq_desc(char *arg)
 151 {
 152         if (arg)
 153                 nr_irq_desc = simple_strtoul(arg, NULL, 0);
 154         return 0;
 155 }
 156
 157 early_param("nr_irq_desc", parse_nr_irq_desc);
 158
 159 DEFINE_DYN_ARRAY(sparse_irqs, sizeof(struct irq_desc), nr_irq_desc, PAGE_SIZE, init_work);
 160
 161 struct irq_desc *irq_to_desc(unsigned int irq)
 162 {
 163         struct irq_desc *desc;
 164
 165         desc = sparse_irqs;
 166         while (desc) {
 167                 if (desc->irq == irq)
 168                         return desc;
 169
 170                 desc = desc->next;
 171         }
 172         return NULL;
 173 }
 174 struct irq_desc *irq_to_desc_alloc(unsigned int irq)
 175 {
 176         struct irq_desc *desc, *desc_pri;
 177         int i;
 178         int count = 0;
 179
 180         desc_pri = desc = sparse_irqs;
 181         while (desc) {
 182                 if (desc->irq == irq)
 183                         return desc;
 184
 185                 desc_pri = desc;
 186                 desc = desc->next;
 187                 count++;
 188         }
 189
 190         /*
 191          *  we run out of pre-allocate ones, allocate more
 192          */
 193         if (!sparse_irqs_free) {
 194                 unsigned long phys;
 195                 unsigned long total_bytes;
 196
 197                 printk(KERN_DEBUG "try to get more irq_desc %d\n", nr_irq_desc);
 198
 199                 total_bytes = sizeof(struct irq_desc) * nr_irq_desc;
 200                 if (after_bootmem)
 201                         desc = kzalloc(total_bytes, GFP_ATOMIC);
 202                 else
 203                         desc = __alloc_bootmem_nopanic(total_bytes, PAGE_SIZE, 0);
 204
 205                 if (!desc)
 206                         panic("please boot with nr_irq_desc= %d\n", count * 2);
 207
 208                 phys = __pa(desc);
 209                 printk(KERN_DEBUG "irq_desc ==> [%#lx - %#lx]\n", phys, phys + total_bytes);
 210
 211                 for (i = 0; i < nr_irq_desc; i++)
 212                         init_one_irq_desc(&desc[i]);
 213
 214                 for (i = 1; i < nr_irq_desc; i++)
 215                         desc[i-1].next = &desc[i];
 216
 217                 /* init kstat_irqs, nr_cpu_ids is ready already */
 218                 init_kstat_irqs(desc, nr_irq_desc, nr_cpu_ids);
 219
 220                 sparse_irqs_free = desc;
 221         }
 222
 223         desc = sparse_irqs_free;
 224         sparse_irqs_free = sparse_irqs_free->next;
 225         desc->next = NULL;
 226         if (desc_pri)
 227                 desc_pri->next = desc;
 228         else
 229                 sparse_irqs = desc;
 230         desc->irq = irq;
 231         printk(KERN_DEBUG "found new irq_desc for irq %d\n", desc->irq);
 232 #ifdef CONFIG_HAVE_SPARSE_IRQ_DEBUG
 233         {
 234                 /* dump the results */
 235                 struct irq_desc *desc;
 236                 unsigned long phys;
 237                 unsigned long bytes = sizeof(struct irq_desc);
 238                 unsigned int irqx;
 239
 240                 printk(KERN_DEBUG "=========================== %d\n", irq);
 241                 printk(KERN_DEBUG "irq_desc dump after get that for %d\n", irq);
 242                 for_each_irq_desc(irqx, desc) {
 243                         phys = __pa(desc);
 244                         printk(KERN_DEBUG "irq_desc %d ==> [%#lx - %#lx]\n", irqx, phys, phys + bytes);
 245                 }
 246                 printk(KERN_DEBUG "===========================\n");
 247         }
 248 #endif
 249         return desc;
 250 }
 251 #else
 252 struct irq_desc *irq_desc;
 253 DEFINE_DYN_ARRAY(irq_desc, sizeof(struct irq_desc), nr_irqs, PAGE_SIZE, init_work);
 254
 255 #endif
 256
 257 #else
 258
 259 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 260         [0 ... NR_IRQS-1] = {
 261                 .status = IRQ_DISABLED,
 262                 .chip = &no_irq_chip,
 263                 .handle_irq = handle_bad_irq,
 264                 .depth = 1,
 265                 .lock = __SPIN_LOCK_UNLOCKED(sparse_irqs->lock),
 266 #ifdef CONFIG_SMP
 267                 .affinity = CPU_MASK_ALL
 268 #endif
 269         }
 270 };
 271
 272 #endif
 273
 274 #ifndef CONFIG_HAVE_SPARSE_IRQ
 275 struct irq_desc *irq_to_desc(unsigned int irq)
 276 {
 277         if (irq < nr_irqs)
 278                 return &irq_desc[irq];
 279
 280         return NULL;
 281 }
 282 struct irq_desc *irq_to_desc_alloc(unsigned int irq)
 283 {
 284         return irq_to_desc(irq);
 285 }
 286 #endif
 287
 288 /*
 289  * What should we do if we get a hw irq event on an illegal vector?
 290  * Each architecture has to answer this themself.
 291  */
 292 static void ack_bad(unsigned int irq)
 293 {
 294         struct irq_desc *desc;
 295
 296         desc = irq_to_desc(irq);
 297         print_irq_desc(irq, desc);
 298         ack_bad_irq(irq);
 299 }
 300
 301 /*
 302  * NOP functions
 303  */
 304 static void noop(unsigned int irq)
 305 {
 306 }
 307
 308 static unsigned int noop_ret(unsigned int irq)
 309 {
 310         return 0;
 311 }
 312
 313 /*
 314  * Generic no controller implementation
 315  */
 316 struct irq_chip no_irq_chip = {
 317         .name           = "none",
 318         .startup        = noop_ret,
 319         .shutdown       = noop,
 320         .enable         = noop,
 321         .disable        = noop,
 322         .ack            = ack_bad,
 323         .end            = noop,
 324 };
 325
 326 /*
 327  * Generic dummy implementation which can be used for
 328  * real dumb interrupt sources
 329  */
 330 struct irq_chip dummy_irq_chip = {
 331         .name           = "dummy",
 332         .startup        = noop_ret,
 333         .shutdown       = noop,
 334         .enable         = noop,
 335         .disable        = noop,
 336         .ack            = noop,
 337         .mask           = noop,
 338         .unmask         = noop,
 339         .end            = noop,
 340 };
 341
 342 /*
 343  * Special, empty irq handler:
 344  */
 345 irqreturn_t no_action(int cpl, void *dev_id)
 346 {
 347         return IRQ_NONE;
 348 }
 349
 350 /**
 351  * handle_IRQ_event - irq action chain handler
 352  * @irq:        the interrupt number
 353  * @action:     the interrupt action chain for this irq
 354  *
 355  * Handles the action chain of an irq event
 356  */
 357 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 358 {
 359         irqreturn_t ret, retval = IRQ_NONE;
 360         unsigned int status = 0;
 361
 362         if (!(action->flags & IRQF_DISABLED))
 363                 local_irq_enable_in_hardirq();
 364
 365         do {
 366                 ret = action->handler(irq, action->dev_id);
 367                 if (ret == IRQ_HANDLED)
 368                         status |= action->flags;
 369                 retval |= ret;
 370                 action = action->next;
 371         } while (action);
 372
 373         if (status & IRQF_SAMPLE_RANDOM)
 374                 add_interrupt_randomness(irq);
 375         local_irq_disable();
 376
 377         return retval;
 378 }
 379
 380 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 381 /**
 382  * __do_IRQ - original all in one highlevel IRQ handler
 383  * @irq:        the interrupt number
 384  *
 385  * __do_IRQ handles all normal device IRQ's (the special
 386  * SMP cross-CPU interrupts have their own specific
 387  * handlers).
 388  *
 389  * This is the original x86 implementation which is used for every
 390  * interrupt type.
 391  */
 392 unsigned int __do_IRQ(unsigned int irq)
 393 {
 394         struct irq_desc *desc = irq_to_desc(irq);
 395         struct irqaction *action;
 396         unsigned int status;
 397
 398         kstat_irqs_this_cpu(desc)++;
 399         if (CHECK_IRQ_PER_CPU(desc->status)) {
 400                 irqreturn_t action_ret;
 401
 402                 /*
 403                  * No locking required for CPU-local interrupts:
 404                  */
 405                 if (desc->chip->ack)
 406                         desc->chip->ack(irq);
 407                 if (likely(!(desc->status & IRQ_DISABLED))) {
 408                         action_ret = handle_IRQ_event(irq, desc->action);
 409                         if (!noirqdebug)
 410                                 note_interrupt(irq, desc, action_ret);
 411                 }
 412                 desc->chip->end(irq);
 413                 return 1;
 414         }
 415
 416         spin_lock(&desc->lock);
 417         if (desc->chip->ack)
 418                 desc->chip->ack(irq);
 419         /*
 420          * REPLAY is when Linux resends an IRQ that was dropped earlier
 421          * WAITING is used by probe to mark irqs that are being tested
 422          */
 423         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 424         status |= IRQ_PENDING; /* we _want_ to handle it */
 425
 426         /*
 427          * If the IRQ is disabled for whatever reason, we cannot
 428          * use the action we have.
 429          */
 430         action = NULL;
 431         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 432                 action = desc->action;
 433                 status &= ~IRQ_PENDING; /* we commit to handling */
 434                 status |= IRQ_INPROGRESS; /* we are handling it */
 435         }
 436         desc->status = status;
 437
 438         /*
 439          * If there is no IRQ handler or it was disabled, exit early.
 440          * Since we set PENDING, if another processor is handling
 441          * a different instance of this same irq, the other processor
 442          * will take care of it.
 443          */
 444         if (unlikely(!action))
 445                 goto out;
 446
 447         /*
 448          * Edge triggered interrupts need to remember
 449          * pending events.
 450          * This applies to any hw interrupts that allow a second
 451          * instance of the same irq to arrive while we are in do_IRQ
 452          * or in the handler. But the code here only handles the _second_
 453          * instance of the irq, not the third or fourth. So it is mostly
 454          * useful for irq hardware that does not mask cleanly in an
 455          * SMP environment.
 456          */
 457         for (;;) {
 458                 irqreturn_t action_ret;
 459
 460                 spin_unlock(&desc->lock);
 461
 462                 action_ret = handle_IRQ_event(irq, action);
 463                 if (!noirqdebug)
 464                         note_interrupt(irq, desc, action_ret);
 465
 466                 spin_lock(&desc->lock);
 467                 if (likely(!(desc->status & IRQ_PENDING)))
 468                         break;
 469                 desc->status &= ~IRQ_PENDING;
 470         }
 471         desc->status &= ~IRQ_INPROGRESS;
 472
 473 out:
 474         /*
 475          * The ->end() handler has to deal with interrupts which got
 476          * disabled while the handler was running.
 477          */
 478         desc->chip->end(irq);
 479         spin_unlock(&desc->lock);
 480
 481         return 1;
 482 }
 483 #endif
 484
 485
 486 #ifdef CONFIG_TRACE_IRQFLAGS
 487 void early_init_irq_lock_class(void)
 488 {
 489 #ifndef CONFIG_HAVE_DYN_ARRAY
 490         int i;
 491
 492         for (i = 0; i < nr_irqs; i++)
 493                 lockdep_set_class(&irq_desc[i].lock, &irq_desc_lock_class);
 494 #endif
 495 }
 496 #endif
 497
 498 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 499 {
 500         struct irq_desc *desc = irq_to_desc(irq);
 501         return desc->kstat_irqs[cpu];
 502 }
 503 EXPORT_SYMBOL(kstat_irqs_cpu);
 504