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