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