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
  19 #include "internals.h"
  20
  21 /*
  22  * lockdep: we want to handle all irq_desc locks as a single lock-class:
  23  */
  24 static struct lock_class_key irq_desc_lock_class;
  25
  26 /**
  27  * handle_bad_irq - handle spurious and unhandled irqs
  28  * @irq:       the interrupt number
  29  * @desc:      description of the interrupt
  30  *
  31  * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
  32  */
  33 void
  34 handle_bad_irq(unsigned int irq, struct irq_desc *desc)
  35 {
  36         print_irq_desc(irq, desc);
  37         kstat_irqs_this_cpu(desc)++;
  38         ack_bad_irq(irq);
  39 }
  40
  41 /*
  42  * Linux has a controller-independent interrupt architecture.
  43  * Every controller has a 'controller-template', that is used
  44  * by the main code to do the right thing. Each driver-visible
  45  * interrupt source is transparently wired to the appropriate
  46  * controller. Thus drivers need not be aware of the
  47  * interrupt-controller.
  48  *
  49  * The code is designed to be easily extended with new/different
  50  * interrupt controllers, without having to do assembly magic or
  51  * having to touch the generic code.
  52  *
  53  * Controller mappings for all interrupt sources:
  54  */
  55 int nr_irqs = NR_IRQS;
  56 EXPORT_SYMBOL_GPL(nr_irqs);
  57
  58 #ifdef CONFIG_HAVE_DYN_ARRAY
  59 static struct irq_desc irq_desc_init = {
  60         .irq = -1U,
  61         .status = IRQ_DISABLED,
  62         .chip = &no_irq_chip,
  63         .handle_irq = handle_bad_irq,
  64         .depth = 1,
  65         .lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
  66 #ifdef CONFIG_SMP
  67         .affinity = CPU_MASK_ALL
  68 #endif
  69 };
  70
  71
  72 static void init_one_irq_desc(struct irq_desc *desc)
  73 {
  74         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
  75         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
  76 }
  77
  78 extern int after_bootmem;
  79 extern void *__alloc_bootmem_nopanic(unsigned long size,
  80                              unsigned long align,
  81                              unsigned long goal);
  82
  83 static void init_kstat_irqs(struct irq_desc *desc, int nr_desc, int nr)
  84 {
  85         unsigned long bytes, total_bytes;
  86         char *ptr;
  87         int i;
  88         unsigned long phys;
  89
  90         /* Compute how many bytes we need per irq and allocate them */
  91         bytes = nr * sizeof(unsigned int);
  92         total_bytes = bytes * nr_desc;
  93         if (after_bootmem)
  94                 ptr = kzalloc(total_bytes, GFP_ATOMIC);
  95         else
  96                 ptr = __alloc_bootmem_nopanic(total_bytes, PAGE_SIZE, 0);
  97
  98         if (!ptr)
  99                 panic(" can not allocate kstat_irqs\n");
 100
 101         phys = __pa(ptr);
 102         printk(KERN_DEBUG "kstat_irqs ==> [%#lx - %#lx]\n", phys, phys + total_bytes);
 103
 104         for (i = 0; i < nr_desc; i++) {
 105                 desc[i].kstat_irqs = (unsigned int *)ptr;
 106                 ptr += bytes;
 107         }
 108 }
 109
 110 #ifdef CONFIG_HAVE_SPARSE_IRQ
 111 static struct irq_desc *sparse_irqs_free;
 112 struct irq_desc *sparse_irqs;
 113 #endif
 114
 115 static void __init init_work(void *data)
 116 {
 117         struct dyn_array *da = data;
 118         int i;
 119         struct  irq_desc *desc;
 120
 121         desc = *da->name;
 122
 123         for (i = 0; i < *da->nr; i++) {
 124                 init_one_irq_desc(&desc[i]);
 125 #ifndef CONFIG_HAVE_SPARSE_IRQ
 126                 desc[i].irq = i;
 127 #endif
 128         }
 129
 130         /* init kstat_irqs, nr_cpu_ids is ready already */
 131         init_kstat_irqs(desc, *da->nr, nr_cpu_ids);
 132
 133 #ifdef CONFIG_HAVE_SPARSE_IRQ
 134         for (i = 1; i < *da->nr; i++)
 135                 desc[i-1].next = &desc[i];
 136
 137         sparse_irqs_free = sparse_irqs;
 138         sparse_irqs = NULL;
 139 #endif
 140 }
 141
 142 #ifdef CONFIG_HAVE_SPARSE_IRQ
 143 static int nr_irq_desc = 32;
 144
 145 static int __init parse_nr_irq_desc(char *arg)
 146 {
 147         if (arg)
 148                 nr_irq_desc = simple_strtoul(arg, NULL, 0);
 149         return 0;
 150 }
 151
 152 early_param("nr_irq_desc", parse_nr_irq_desc);
 153
 154 DEFINE_DYN_ARRAY(sparse_irqs, sizeof(struct irq_desc), nr_irq_desc, PAGE_SIZE, init_work);
 155
 156 struct irq_desc *irq_to_desc(unsigned int irq)
 157 {
 158         struct irq_desc *desc;
 159
 160         desc = sparse_irqs;
 161         while (desc) {
 162                 if (desc->irq == irq)
 163                         return desc;
 164
 165                 desc = desc->next;
 166         }
 167         return NULL;
 168 }
 169 struct irq_desc *irq_to_desc_alloc(unsigned int irq)
 170 {
 171         struct irq_desc *desc, *desc_pri;
 172         int i;
 173         int count = 0;
 174
 175         desc_pri = desc = sparse_irqs;
 176         while (desc) {
 177                 if (desc->irq == irq)
 178                         return desc;
 179
 180                 desc_pri = desc;
 181                 desc = desc->next;
 182                 count++;
 183         }
 184
 185         /*
 186          *  we run out of pre-allocate ones, allocate more
 187          */
 188         if (!sparse_irqs_free) {
 189                 unsigned long phys;
 190                 unsigned long total_bytes;
 191
 192                 printk(KERN_DEBUG "try to get more irq_desc %d\n", nr_irq_desc);
 193
 194                 total_bytes = sizeof(struct irq_desc) * nr_irq_desc;
 195                 if (after_bootmem)
 196                         desc = kzalloc(total_bytes, GFP_ATOMIC);
 197                 else
 198                         desc = __alloc_bootmem_nopanic(total_bytes, PAGE_SIZE, 0);
 199
 200                 if (!desc)
 201                         panic("please boot with nr_irq_desc= %d\n", count * 2);
 202
 203                 phys = __pa(desc);
 204                 printk(KERN_DEBUG "irq_desc ==> [%#lx - %#lx]\n", phys, phys + total_bytes);
 205
 206                 for (i = 0; i < nr_irq_desc; i++)
 207                         init_one_irq_desc(&desc[i]);
 208
 209                 for (i = 1; i < nr_irq_desc; i++)
 210                         desc[i-1].next = &desc[i];
 211
 212                 /* init kstat_irqs, nr_cpu_ids is ready already */
 213                 init_kstat_irqs(desc, nr_irq_desc, nr_cpu_ids);
 214
 215                 sparse_irqs_free = desc;
 216         }
 217
 218         desc = sparse_irqs_free;
 219         sparse_irqs_free = sparse_irqs_free->next;
 220         desc->next = NULL;
 221         if (desc_pri)
 222                 desc_pri->next = desc;
 223         else
 224                 sparse_irqs = desc;
 225         desc->irq = irq;
 226         printk(KERN_DEBUG "found new irq_desc for irq %d\n", desc->irq);
 227 #ifdef CONFIG_HAVE_SPARSE_IRQ_DEBUG
 228         {
 229                 /* dump the results */
 230                 struct irq_desc *desc;
 231                 unsigned long phys;
 232                 unsigned long bytes = sizeof(struct irq_desc);
 233                 unsigned int irqx;
 234
 235                 printk(KERN_DEBUG "=========================== %d\n", irq);
 236                 printk(KERN_DEBUG "irq_desc dump after get that for %d\n", irq);
 237                 for_each_irq_desc(irqx, desc) {
 238                         phys = __pa(desc);
 239                         printk(KERN_DEBUG "irq_desc %d ==> [%#lx - %#lx]\n", irqx, phys, phys + bytes);
 240                 }
 241                 printk(KERN_DEBUG "===========================\n");
 242         }
 243 #endif
 244         return desc;
 245 }
 246 #else
 247 struct irq_desc *irq_desc;
 248 DEFINE_DYN_ARRAY(irq_desc, sizeof(struct irq_desc), nr_irqs, PAGE_SIZE, init_work);
 249
 250 #endif
 251
 252 #else
 253
 254 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 255         [0 ... NR_IRQS-1] = {
 256                 .status = IRQ_DISABLED,
 257                 .chip = &no_irq_chip,
 258                 .handle_irq = handle_bad_irq,
 259                 .depth = 1,
 260                 .lock = __SPIN_LOCK_UNLOCKED(sparse_irqs->lock),
 261 #ifdef CONFIG_SMP
 262                 .affinity = CPU_MASK_ALL
 263 #endif
 264         }
 265 };
 266
 267 #endif
 268
 269 #ifndef CONFIG_HAVE_SPARSE_IRQ
 270 struct irq_desc *irq_to_desc(unsigned int irq)
 271 {
 272         if (irq < nr_irqs)
 273                 return &irq_desc[irq];
 274
 275         return NULL;
 276 }
 277 struct irq_desc *irq_to_desc_alloc(unsigned int irq)
 278 {
 279         return irq_to_desc(irq);
 280 }
 281 #endif
 282
 283 /*
 284  * What should we do if we get a hw irq event on an illegal vector?
 285  * Each architecture has to answer this themself.
 286  */
 287 static void ack_bad(unsigned int irq)
 288 {
 289         struct irq_desc *desc;
 290
 291         desc = irq_to_desc(irq);
 292         print_irq_desc(irq, desc);
 293         ack_bad_irq(irq);
 294 }
 295
 296 /*
 297  * NOP functions
 298  */
 299 static void noop(unsigned int irq)
 300 {
 301 }
 302
 303 static unsigned int noop_ret(unsigned int irq)
 304 {
 305         return 0;
 306 }
 307
 308 /*
 309  * Generic no controller implementation
 310  */
 311 struct irq_chip no_irq_chip = {
 312         .name           = "none",
 313         .startup        = noop_ret,
 314         .shutdown       = noop,
 315         .enable         = noop,
 316         .disable        = noop,
 317         .ack            = ack_bad,
 318         .end            = noop,
 319 };
 320
 321 /*
 322  * Generic dummy implementation which can be used for
 323  * real dumb interrupt sources
 324  */
 325 struct irq_chip dummy_irq_chip = {
 326         .name           = "dummy",
 327         .startup        = noop_ret,
 328         .shutdown       = noop,
 329         .enable         = noop,
 330         .disable        = noop,
 331         .ack            = noop,
 332         .mask           = noop,
 333         .unmask         = noop,
 334         .end            = noop,
 335 };
 336
 337 /*
 338  * Special, empty irq handler:
 339  */
 340 irqreturn_t no_action(int cpl, void *dev_id)
 341 {
 342         return IRQ_NONE;
 343 }
 344
 345 /**
 346  * handle_IRQ_event - irq action chain handler
 347  * @irq:        the interrupt number
 348  * @action:     the interrupt action chain for this irq
 349  *
 350  * Handles the action chain of an irq event
 351  */
 352 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 353 {
 354         irqreturn_t ret, retval = IRQ_NONE;
 355         unsigned int status = 0;
 356
 357         if (!(action->flags & IRQF_DISABLED))
 358                 local_irq_enable_in_hardirq();
 359
 360         do {
 361                 ret = action->handler(irq, action->dev_id);
 362                 if (ret == IRQ_HANDLED)
 363                         status |= action->flags;
 364                 retval |= ret;
 365                 action = action->next;
 366         } while (action);
 367
 368         if (status & IRQF_SAMPLE_RANDOM)
 369                 add_interrupt_randomness(irq);
 370         local_irq_disable();
 371
 372         return retval;
 373 }
 374
 375 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 376 /**
 377  * __do_IRQ - original all in one highlevel IRQ handler
 378  * @irq:        the interrupt number
 379  *
 380  * __do_IRQ handles all normal device IRQ's (the special
 381  * SMP cross-CPU interrupts have their own specific
 382  * handlers).
 383  *
 384  * This is the original x86 implementation which is used for every
 385  * interrupt type.
 386  */
 387 unsigned int __do_IRQ(unsigned int irq)
 388 {
 389         struct irq_desc *desc = irq_to_desc(irq);
 390         struct irqaction *action;
 391         unsigned int status;
 392
 393         kstat_irqs_this_cpu(desc)++;
 394         if (CHECK_IRQ_PER_CPU(desc->status)) {
 395                 irqreturn_t action_ret;
 396
 397                 /*
 398                  * No locking required for CPU-local interrupts:
 399                  */
 400                 if (desc->chip->ack)
 401                         desc->chip->ack(irq);
 402                 if (likely(!(desc->status & IRQ_DISABLED))) {
 403                         action_ret = handle_IRQ_event(irq, desc->action);
 404                         if (!noirqdebug)
 405                                 note_interrupt(irq, desc, action_ret);
 406                 }
 407                 desc->chip->end(irq);
 408                 return 1;
 409         }
 410
 411         spin_lock(&desc->lock);
 412         if (desc->chip->ack)
 413                 desc->chip->ack(irq);
 414         /*
 415          * REPLAY is when Linux resends an IRQ that was dropped earlier
 416          * WAITING is used by probe to mark irqs that are being tested
 417          */
 418         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 419         status |= IRQ_PENDING; /* we _want_ to handle it */
 420
 421         /*
 422          * If the IRQ is disabled for whatever reason, we cannot
 423          * use the action we have.
 424          */
 425         action = NULL;
 426         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 427                 action = desc->action;
 428                 status &= ~IRQ_PENDING; /* we commit to handling */
 429                 status |= IRQ_INPROGRESS; /* we are handling it */
 430         }
 431         desc->status = status;
 432
 433         /*
 434          * If there is no IRQ handler or it was disabled, exit early.
 435          * Since we set PENDING, if another processor is handling
 436          * a different instance of this same irq, the other processor
 437          * will take care of it.
 438          */
 439         if (unlikely(!action))
 440                 goto out;
 441
 442         /*
 443          * Edge triggered interrupts need to remember
 444          * pending events.
 445          * This applies to any hw interrupts that allow a second
 446          * instance of the same irq to arrive while we are in do_IRQ
 447          * or in the handler. But the code here only handles the _second_
 448          * instance of the irq, not the third or fourth. So it is mostly
 449          * useful for irq hardware that does not mask cleanly in an
 450          * SMP environment.
 451          */
 452         for (;;) {
 453                 irqreturn_t action_ret;
 454
 455                 spin_unlock(&desc->lock);
 456
 457                 action_ret = handle_IRQ_event(irq, action);
 458                 if (!noirqdebug)
 459                         note_interrupt(irq, desc, action_ret);
 460
 461                 spin_lock(&desc->lock);
 462                 if (likely(!(desc->status & IRQ_PENDING)))
 463                         break;
 464                 desc->status &= ~IRQ_PENDING;
 465         }
 466         desc->status &= ~IRQ_INPROGRESS;
 467
 468 out:
 469         /*
 470          * The ->end() handler has to deal with interrupts which got
 471          * disabled while the handler was running.
 472          */
 473         desc->chip->end(irq);
 474         spin_unlock(&desc->lock);
 475
 476         return 1;
 477 }
 478 #endif
 479
 480
 481 #ifdef CONFIG_TRACE_IRQFLAGS
 482 void early_init_irq_lock_class(void)
 483 {
 484 #ifndef CONFIG_HAVE_DYN_ARRAY
 485         int i;
 486
 487         for (i = 0; i < nr_irqs; i++)
 488                 lockdep_set_class(&irq_desc[i].lock, &irq_desc_lock_class);
 489 #endif
 490 }
 491 #endif
 492
 493 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 494 {
 495         struct irq_desc *desc = irq_to_desc(irq);
 496         return desc->kstat_irqs[cpu];
 497 }
 498 EXPORT_SYMBOL(kstat_irqs_cpu);
 499