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