SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 #include <linux/bootmem.h>
  21
  22 #include "internals.h"
  23
  24 /*
  25  * lockdep: we want to handle all irq_desc locks as a single lock-class:
  26  */
  27 struct lock_class_key irq_desc_lock_class;
  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 handle_bad_irq(unsigned int irq, struct irq_desc *desc)
  37 {
  38         print_irq_desc(irq, desc);
  39         kstat_incr_irqs_this_cpu(irq, desc);
  40         ack_bad_irq(irq);
  41 }
  42
  43 /*
  44  * Linux has a controller-independent interrupt architecture.
  45  * Every controller has a 'controller-template', that is used
  46  * by the main code to do the right thing. Each driver-visible
  47  * interrupt source is transparently wired to the appropriate
  48  * controller. Thus drivers need not be aware of the
  49  * interrupt-controller.
  50  *
  51  * The code is designed to be easily extended with new/different
  52  * interrupt controllers, without having to do assembly magic or
  53  * having to touch the generic code.
  54  *
  55  * Controller mappings for all interrupt sources:
  56  */
  57 int nr_irqs = NR_IRQS;
  58 EXPORT_SYMBOL_GPL(nr_irqs);
  59
  60 #ifdef CONFIG_SPARSE_IRQ
  61
  62 #ifndef max_nr_irqs
  63 #define max_nr_irqs(nr_cpus)    NR_IRQS
  64 #endif
  65
  66 static struct irq_desc irq_desc_init = {
  67         .irq        = -1,
  68         .status     = IRQ_DISABLED,
  69         .chip       = &no_irq_chip,
  70         .handle_irq = handle_bad_irq,
  71         .depth      = 1,
  72         .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
  73 };
  74
  75 void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
  76 {
  77         unsigned long bytes;
  78         char *ptr;
  79         int node;
  80
  81         /* Compute how many bytes we need per irq and allocate them */
  82         bytes = nr * sizeof(unsigned int);
  83
  84         node = cpu_to_node(cpu);
  85         ptr = kzalloc_node(bytes, GFP_ATOMIC, node);
  86         printk(KERN_DEBUG "  alloc kstat_irqs on cpu %d node %d\n", cpu, node);
  87
  88         if (ptr)
  89                 desc->kstat_irqs = (unsigned int *)ptr;
  90 }
  91
  92 static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
  93 {
  94         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
  95
  96         spin_lock_init(&desc->lock);
  97         desc->irq = irq;
  98 #ifdef CONFIG_SMP
  99         desc->cpu = cpu;
 100 #endif
 101         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 102         init_kstat_irqs(desc, cpu, nr_cpu_ids);
 103         if (!desc->kstat_irqs) {
 104                 printk(KERN_ERR "can not alloc kstat_irqs\n");
 105                 BUG_ON(1);
 106         }
 107         if (!init_alloc_desc_masks(desc, cpu, false)) {
 108                 printk(KERN_ERR "can not alloc irq_desc cpumasks\n");
 109                 BUG_ON(1);
 110         }
 111         arch_init_chip_data(desc, cpu);
 112 }
 113
 114 /*
 115  * Protect the sparse_irqs:
 116  */
 117 DEFINE_SPINLOCK(sparse_irq_lock);
 118
 119 struct irq_desc **irq_desc_ptrs __read_mostly;
 120
 121 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
 122         [0 ... NR_IRQS_LEGACY-1] = {
 123                 .irq        = -1,
 124                 .status     = IRQ_DISABLED,
 125                 .chip       = &no_irq_chip,
 126                 .handle_irq = handle_bad_irq,
 127                 .depth      = 1,
 128                 .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
 129         }
 130 };
 131
 132 static unsigned int *kstat_irqs_legacy;
 133
 134 int __init early_irq_init(void)
 135 {
 136         struct irq_desc *desc;
 137         int legacy_count;
 138         int i;
 139
 140         /* initialize nr_irqs based on nr_cpu_ids */
 141         nr_irqs = max_nr_irqs(nr_cpu_ids);
 142
 143         printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs);
 144
 145         desc = irq_desc_legacy;
 146         legacy_count = ARRAY_SIZE(irq_desc_legacy);
 147
 148         /* allocate irq_desc_ptrs array based on nr_irqs */
 149         irq_desc_ptrs = alloc_bootmem(nr_irqs * sizeof(void *));
 150
 151         /* allocate based on nr_cpu_ids */
 152         /* FIXME: invert kstat_irgs, and it'd be a per_cpu_alloc'd thing */
 153         kstat_irqs_legacy = alloc_bootmem(NR_IRQS_LEGACY * nr_cpu_ids *
 154                                           sizeof(int));
 155
 156         for (i = 0; i < legacy_count; i++) {
 157                 desc[i].irq = i;
 158                 desc[i].kstat_irqs = kstat_irqs_legacy + i * nr_cpu_ids;
 159                 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
 160                 init_alloc_desc_masks(&desc[i], 0, true);
 161                 irq_desc_ptrs[i] = desc + i;
 162         }
 163
 164         for (i = legacy_count; i < nr_irqs; i++)
 165                 irq_desc_ptrs[i] = NULL;
 166
 167         return arch_early_irq_init();
 168 }
 169
 170 struct irq_desc *irq_to_desc(unsigned int irq)
 171 {
 172         if (irq_desc_ptrs && irq < nr_irqs)
 173                 return irq_desc_ptrs[irq];
 174
 175         return NULL;
 176 }
 177
 178 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
 179 {
 180         struct irq_desc *desc;
 181         unsigned long flags;
 182         int node;
 183
 184         if (irq >= nr_irqs) {
 185                 WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
 186                         irq, nr_irqs);
 187                 return NULL;
 188         }
 189
 190         desc = irq_desc_ptrs[irq];
 191         if (desc)
 192                 return desc;
 193
 194         spin_lock_irqsave(&sparse_irq_lock, flags);
 195
 196         /* We have to check it to avoid races with another CPU */
 197         desc = irq_desc_ptrs[irq];
 198         if (desc)
 199                 goto out_unlock;
 200
 201         node = cpu_to_node(cpu);
 202         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
 203         printk(KERN_DEBUG "  alloc irq_desc for %d on cpu %d node %d\n",
 204                  irq, cpu, node);
 205         if (!desc) {
 206                 printk(KERN_ERR "can not alloc irq_desc\n");
 207                 BUG_ON(1);
 208         }
 209         init_one_irq_desc(irq, desc, cpu);
 210
 211         irq_desc_ptrs[irq] = desc;
 212
 213 out_unlock:
 214         spin_unlock_irqrestore(&sparse_irq_lock, flags);
 215
 216         return desc;
 217 }
 218
 219 #else /* !CONFIG_SPARSE_IRQ */
 220
 221 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 222         [0 ... NR_IRQS-1] = {
 223                 .status = IRQ_DISABLED,
 224                 .chip = &no_irq_chip,
 225                 .handle_irq = handle_bad_irq,
 226                 .depth = 1,
 227                 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
 228         }
 229 };
 230
 231 int __init early_irq_init(void)
 232 {
 233         struct irq_desc *desc;
 234         int count;
 235         int i;
 236
 237         printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
 238
 239         desc = irq_desc;
 240         count = ARRAY_SIZE(irq_desc);
 241
 242         for (i = 0; i < count; i++) {
 243                 desc[i].irq = i;
 244                 init_alloc_desc_masks(&desc[i], 0, true);
 245         }
 246         return arch_early_irq_init();
 247 }
 248
 249 struct irq_desc *irq_to_desc(unsigned int irq)
 250 {
 251         return (irq < NR_IRQS) ? irq_desc + irq : NULL;
 252 }
 253
 254 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
 255 {
 256         return irq_to_desc(irq);
 257 }
 258 #endif /* !CONFIG_SPARSE_IRQ */
 259
 260 /*
 261  * What should we do if we get a hw irq event on an illegal vector?
 262  * Each architecture has to answer this themself.
 263  */
 264 static void ack_bad(unsigned int irq)
 265 {
 266         struct irq_desc *desc = irq_to_desc(irq);
 267
 268         print_irq_desc(irq, desc);
 269         ack_bad_irq(irq);
 270 }
 271
 272 /*
 273  * NOP functions
 274  */
 275 static void noop(unsigned int irq)
 276 {
 277 }
 278
 279 static unsigned int noop_ret(unsigned int irq)
 280 {
 281         return 0;
 282 }
 283
 284 /*
 285  * Generic no controller implementation
 286  */
 287 struct irq_chip no_irq_chip = {
 288         .name           = "none",
 289         .startup        = noop_ret,
 290         .shutdown       = noop,
 291         .enable         = noop,
 292         .disable        = noop,
 293         .ack            = ack_bad,
 294         .end            = noop,
 295 };
 296
 297 /*
 298  * Generic dummy implementation which can be used for
 299  * real dumb interrupt sources
 300  */
 301 struct irq_chip dummy_irq_chip = {
 302         .name           = "dummy",
 303         .startup        = noop_ret,
 304         .shutdown       = noop,
 305         .enable         = noop,
 306         .disable        = noop,
 307         .ack            = noop,
 308         .mask           = noop,
 309         .unmask         = noop,
 310         .end            = noop,
 311 };
 312
 313 /*
 314  * Special, empty irq handler:
 315  */
 316 irqreturn_t no_action(int cpl, void *dev_id)
 317 {
 318         return IRQ_NONE;
 319 }
 320
 321 /**
 322  * handle_IRQ_event - irq action chain handler
 323  * @irq:        the interrupt number
 324  * @action:     the interrupt action chain for this irq
 325  *
 326  * Handles the action chain of an irq event
 327  */
 328 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 329 {
 330         irqreturn_t ret, retval = IRQ_NONE;
 331         unsigned int status = 0;
 332
 333         if (!(action->flags & IRQF_DISABLED))
 334                 local_irq_enable_in_hardirq();
 335
 336         do {
 337                 ret = action->handler(irq, action->dev_id);
 338                 if (ret == IRQ_HANDLED)
 339                         status |= action->flags;
 340                 retval |= ret;
 341                 action = action->next;
 342         } while (action);
 343
 344         if (status & IRQF_SAMPLE_RANDOM)
 345                 add_interrupt_randomness(irq);
 346         local_irq_disable();
 347
 348         return retval;
 349 }
 350
 351 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 352 /**
 353  * __do_IRQ - original all in one highlevel IRQ handler
 354  * @irq:        the interrupt number
 355  *
 356  * __do_IRQ handles all normal device IRQ's (the special
 357  * SMP cross-CPU interrupts have their own specific
 358  * handlers).
 359  *
 360  * This is the original x86 implementation which is used for every
 361  * interrupt type.
 362  */
 363 unsigned int __do_IRQ(unsigned int irq)
 364 {
 365         struct irq_desc *desc = irq_to_desc(irq);
 366         struct irqaction *action;
 367         unsigned int status;
 368
 369         kstat_incr_irqs_this_cpu(irq, desc);
 370
 371         if (CHECK_IRQ_PER_CPU(desc->status)) {
 372                 irqreturn_t action_ret;
 373
 374                 /*
 375                  * No locking required for CPU-local interrupts:
 376                  */
 377                 if (desc->chip->ack) {
 378                         desc->chip->ack(irq);
 379                         /* get new one */
 380                         desc = irq_remap_to_desc(irq, desc);
 381                 }
 382                 if (likely(!(desc->status & IRQ_DISABLED))) {
 383                         action_ret = handle_IRQ_event(irq, desc->action);
 384                         if (!noirqdebug)
 385                                 note_interrupt(irq, desc, action_ret);
 386                 }
 387                 desc->chip->end(irq);
 388                 return 1;
 389         }
 390
 391         spin_lock(&desc->lock);
 392         if (desc->chip->ack) {
 393                 desc->chip->ack(irq);
 394                 desc = irq_remap_to_desc(irq, desc);
 395         }
 396         /*
 397          * REPLAY is when Linux resends an IRQ that was dropped earlier
 398          * WAITING is used by probe to mark irqs that are being tested
 399          */
 400         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 401         status |= IRQ_PENDING; /* we _want_ to handle it */
 402
 403         /*
 404          * If the IRQ is disabled for whatever reason, we cannot
 405          * use the action we have.
 406          */
 407         action = NULL;
 408         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 409                 action = desc->action;
 410                 status &= ~IRQ_PENDING; /* we commit to handling */
 411                 status |= IRQ_INPROGRESS; /* we are handling it */
 412         }
 413         desc->status = status;
 414
 415         /*
 416          * If there is no IRQ handler or it was disabled, exit early.
 417          * Since we set PENDING, if another processor is handling
 418          * a different instance of this same irq, the other processor
 419          * will take care of it.
 420          */
 421         if (unlikely(!action))
 422                 goto out;
 423
 424         /*
 425          * Edge triggered interrupts need to remember
 426          * pending events.
 427          * This applies to any hw interrupts that allow a second
 428          * instance of the same irq to arrive while we are in do_IRQ
 429          * or in the handler. But the code here only handles the _second_
 430          * instance of the irq, not the third or fourth. So it is mostly
 431          * useful for irq hardware that does not mask cleanly in an
 432          * SMP environment.
 433          */
 434         for (;;) {
 435                 irqreturn_t action_ret;
 436
 437                 spin_unlock(&desc->lock);
 438
 439                 action_ret = handle_IRQ_event(irq, action);
 440                 if (!noirqdebug)
 441                         note_interrupt(irq, desc, action_ret);
 442
 443                 spin_lock(&desc->lock);
 444                 if (likely(!(desc->status & IRQ_PENDING)))
 445                         break;
 446                 desc->status &= ~IRQ_PENDING;
 447         }
 448         desc->status &= ~IRQ_INPROGRESS;
 449
 450 out:
 451         /*
 452          * The ->end() handler has to deal with interrupts which got
 453          * disabled while the handler was running.
 454          */
 455         desc->chip->end(irq);
 456         spin_unlock(&desc->lock);
 457
 458         return 1;
 459 }
 460 #endif
 461
 462 void early_init_irq_lock_class(void)
 463 {
 464         struct irq_desc *desc;
 465         int i;
 466
 467         for_each_irq_desc(i, desc) {
 468                 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 469         }
 470 }
 471
 472 #ifdef CONFIG_SPARSE_IRQ
 473 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 474 {
 475         struct irq_desc *desc = irq_to_desc(irq);
 476         return desc ? desc->kstat_irqs[cpu] : 0;
 477 }
 478 #endif
 479 EXPORT_SYMBOL(kstat_irqs_cpu);
 480