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