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 #ifdef CONFIG_HAVE_DYN_ARRAY
  38         kstat_irqs_this_cpu(desc)++;
  39 #else
  40         kstat_irqs_this_cpu(irq)++;
  41 #endif
  42         ack_bad_irq(irq);
  43 }
  44
  45 /*
  46  * Linux has a controller-independent interrupt architecture.
  47  * Every controller has a 'controller-template', that is used
  48  * by the main code to do the right thing. Each driver-visible
  49  * interrupt source is transparently wired to the appropriate
  50  * controller. Thus drivers need not be aware of the
  51  * interrupt-controller.
  52  *
  53  * The code is designed to be easily extended with new/different
  54  * interrupt controllers, without having to do assembly magic or
  55  * having to touch the generic code.
  56  *
  57  * Controller mappings for all interrupt sources:
  58  */
  59 int nr_irqs = NR_IRQS;
  60 EXPORT_SYMBOL_GPL(nr_irqs);
  61
  62 #ifdef CONFIG_HAVE_DYN_ARRAY
  63 static struct irq_desc irq_desc_init = {
  64         .irq = -1U,
  65         .status = IRQ_DISABLED,
  66         .chip = &no_irq_chip,
  67         .handle_irq = handle_bad_irq,
  68         .depth = 1,
  69         .lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
  70 #ifdef CONFIG_SMP
  71         .affinity = CPU_MASK_ALL
  72 #endif
  73 };
  74
  75
  76 static void init_one_irq_desc(struct irq_desc *desc)
  77 {
  78         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
  79         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
  80 }
  81
  82 extern int after_bootmem;
  83 extern void *__alloc_bootmem_nopanic(unsigned long size,
  84                              unsigned long align,
  85                              unsigned long goal);
  86
  87 static void init_kstat_irqs(struct irq_desc *desc, int nr_desc, int nr)
  88 {
  89         unsigned long bytes, total_bytes;
  90         char *ptr;
  91         int i;
  92         unsigned long phys;
  93
  94         /* Compute how many bytes we need per irq and allocate them */
  95         bytes = nr * sizeof(unsigned int);
  96         total_bytes = bytes * nr_desc;
  97         if (after_bootmem)
  98                 ptr = kzalloc(total_bytes, GFP_ATOMIC);
  99         else
 100                 ptr = __alloc_bootmem_nopanic(total_bytes, PAGE_SIZE, 0);
 101
 102         if (!ptr)
 103                 panic(" can not allocate kstat_irqs\n");
 104
 105         phys = __pa(ptr);
 106         printk(KERN_DEBUG "kstat_irqs ==> [%#lx - %#lx]\n", phys, phys + total_bytes);
 107
 108         for (i = 0; i < nr_desc; i++) {
 109                 desc[i].kstat_irqs = (unsigned int *)ptr;
 110                 ptr += bytes;
 111         }
 112 }
 113
 114 #ifdef CONFIG_HAVE_SPARSE_IRQ
 115 /*
 116  * Protect the sparse_irqs_free freelist:
 117  */
 118 static DEFINE_SPINLOCK(sparse_irq_lock);
 119 static struct irq_desc *sparse_irqs_free;
 120 struct irq_desc *sparse_irqs;
 121 #endif
 122
 123 static void __init init_work(void *data)
 124 {
 125         struct dyn_array *da = data;
 126         int i;
 127         struct  irq_desc *desc;
 128
 129         desc = *da->name;
 130
 131         for (i = 0; i < *da->nr; i++) {
 132                 init_one_irq_desc(&desc[i]);
 133 #ifndef CONFIG_HAVE_SPARSE_IRQ
 134                 desc[i].irq = i;
 135 #endif
 136         }
 137
 138         /* init kstat_irqs, nr_cpu_ids is ready already */
 139         init_kstat_irqs(desc, *da->nr, nr_cpu_ids);
 140
 141 #ifdef CONFIG_HAVE_SPARSE_IRQ
 142         for (i = 1; i < *da->nr; i++)
 143                 desc[i-1].next = &desc[i];
 144
 145         sparse_irqs_free = sparse_irqs;
 146         sparse_irqs = NULL;
 147 #endif
 148 }
 149
 150 #ifdef CONFIG_HAVE_SPARSE_IRQ
 151 static int nr_irq_desc = 32;
 152
 153 static int __init parse_nr_irq_desc(char *arg)
 154 {
 155         if (arg)
 156                 nr_irq_desc = simple_strtoul(arg, NULL, 0);
 157         return 0;
 158 }
 159
 160 early_param("nr_irq_desc", parse_nr_irq_desc);
 161
 162 DEFINE_DYN_ARRAY(sparse_irqs, sizeof(struct irq_desc), nr_irq_desc, PAGE_SIZE, init_work);
 163
 164 struct irq_desc *irq_to_desc(unsigned int irq)
 165 {
 166         struct irq_desc *desc;
 167
 168         desc = sparse_irqs;
 169         while (desc) {
 170                 if (desc->irq == irq)
 171                         return desc;
 172
 173                 desc = desc->next;
 174         }
 175         return NULL;
 176 }
 177
 178 struct irq_desc *irq_to_desc_alloc(unsigned int irq)
 179 {
 180         struct irq_desc *desc, *desc_pri;
 181         unsigned long flags;
 182         int count = 0;
 183         int i;
 184
 185         desc_pri = desc = sparse_irqs;
 186         while (desc) {
 187                 if (desc->irq == irq)
 188                         return desc;
 189
 190                 desc_pri = desc;
 191                 desc = desc->next;
 192                 count++;
 193         }
 194
 195         spin_lock_irqsave(&sparse_irq_lock, flags);
 196         /*
 197          *  we run out of pre-allocate ones, allocate more
 198          */
 199         if (!sparse_irqs_free) {
 200                 unsigned long phys;
 201                 unsigned long total_bytes;
 202
 203                 printk(KERN_DEBUG "try to get more irq_desc %d\n", nr_irq_desc);
 204
 205                 total_bytes = sizeof(struct irq_desc) * nr_irq_desc;
 206                 if (after_bootmem)
 207                         desc = kzalloc(total_bytes, GFP_ATOMIC);
 208                 else
 209                         desc = __alloc_bootmem_nopanic(total_bytes, PAGE_SIZE, 0);
 210
 211                 if (!desc)
 212                         panic("please boot with nr_irq_desc= %d\n", count * 2);
 213
 214                 phys = __pa(desc);
 215                 printk(KERN_DEBUG "irq_desc ==> [%#lx - %#lx]\n", phys, phys + total_bytes);
 216
 217                 for (i = 0; i < nr_irq_desc; i++)
 218                         init_one_irq_desc(&desc[i]);
 219
 220                 for (i = 1; i < nr_irq_desc; i++)
 221                         desc[i-1].next = &desc[i];
 222
 223                 /* init kstat_irqs, nr_cpu_ids is ready already */
 224                 init_kstat_irqs(desc, nr_irq_desc, nr_cpu_ids);
 225
 226                 sparse_irqs_free = desc;
 227         }
 228
 229         desc = sparse_irqs_free;
 230         sparse_irqs_free = sparse_irqs_free->next;
 231         desc->next = NULL;
 232         if (desc_pri)
 233                 desc_pri->next = desc;
 234         else
 235                 sparse_irqs = desc;
 236         desc->irq = irq;
 237
 238         spin_unlock_irqrestore(&sparse_irq_lock, flags);
 239
 240         return desc;
 241 }
 242 #else
 243 struct irq_desc *irq_desc;
 244 DEFINE_DYN_ARRAY(irq_desc, sizeof(struct irq_desc), nr_irqs, PAGE_SIZE, init_work);
 245
 246 #endif
 247
 248 #else
 249
 250 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 251         [0 ... NR_IRQS-1] = {
 252                 .status = IRQ_DISABLED,
 253                 .chip = &no_irq_chip,
 254                 .handle_irq = handle_bad_irq,
 255                 .depth = 1,
 256                 .lock = __SPIN_LOCK_UNLOCKED(sparse_irqs->lock),
 257 #ifdef CONFIG_SMP
 258                 .affinity = CPU_MASK_ALL
 259 #endif
 260         }
 261 };
 262
 263 #endif
 264
 265 #ifndef CONFIG_HAVE_SPARSE_IRQ
 266 struct irq_desc *irq_to_desc(unsigned int irq)
 267 {
 268         if (irq < nr_irqs)
 269                 return &irq_desc[irq];
 270
 271         return NULL;
 272 }
 273 struct irq_desc *irq_to_desc_alloc(unsigned int irq)
 274 {
 275         return irq_to_desc(irq);
 276 }
 277 #endif
 278
 279 /*
 280  * What should we do if we get a hw irq event on an illegal vector?
 281  * Each architecture has to answer this themself.
 282  */
 283 static void ack_bad(unsigned int irq)
 284 {
 285         struct irq_desc *desc;
 286
 287         desc = irq_to_desc(irq);
 288         print_irq_desc(irq, desc);
 289         ack_bad_irq(irq);
 290 }
 291
 292 /*
 293  * NOP functions
 294  */
 295 static void noop(unsigned int irq)
 296 {
 297 }
 298
 299 static unsigned int noop_ret(unsigned int irq)
 300 {
 301         return 0;
 302 }
 303
 304 /*
 305  * Generic no controller implementation
 306  */
 307 struct irq_chip no_irq_chip = {
 308         .name           = "none",
 309         .startup        = noop_ret,
 310         .shutdown       = noop,
 311         .enable         = noop,
 312         .disable        = noop,
 313         .ack            = ack_bad,
 314         .end            = noop,
 315 };
 316
 317 /*
 318  * Generic dummy implementation which can be used for
 319  * real dumb interrupt sources
 320  */
 321 struct irq_chip dummy_irq_chip = {
 322         .name           = "dummy",
 323         .startup        = noop_ret,
 324         .shutdown       = noop,
 325         .enable         = noop,
 326         .disable        = noop,
 327         .ack            = noop,
 328         .mask           = noop,
 329         .unmask         = noop,
 330         .end            = noop,
 331 };
 332
 333 /*
 334  * Special, empty irq handler:
 335  */
 336 irqreturn_t no_action(int cpl, void *dev_id)
 337 {
 338         return IRQ_NONE;
 339 }
 340
 341 /**
 342  * handle_IRQ_event - irq action chain handler
 343  * @irq:        the interrupt number
 344  * @action:     the interrupt action chain for this irq
 345  *
 346  * Handles the action chain of an irq event
 347  */
 348 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 349 {
 350         irqreturn_t ret, retval = IRQ_NONE;
 351         unsigned int status = 0;
 352
 353         if (!(action->flags & IRQF_DISABLED))
 354                 local_irq_enable_in_hardirq();
 355
 356         do {
 357                 ret = action->handler(irq, action->dev_id);
 358                 if (ret == IRQ_HANDLED)
 359                         status |= action->flags;
 360                 retval |= ret;
 361                 action = action->next;
 362         } while (action);
 363
 364         if (status & IRQF_SAMPLE_RANDOM)
 365                 add_interrupt_randomness(irq);
 366         local_irq_disable();
 367
 368         return retval;
 369 }
 370
 371 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 372 /**
 373  * __do_IRQ - original all in one highlevel IRQ handler
 374  * @irq:        the interrupt number
 375  *
 376  * __do_IRQ handles all normal device IRQ's (the special
 377  * SMP cross-CPU interrupts have their own specific
 378  * handlers).
 379  *
 380  * This is the original x86 implementation which is used for every
 381  * interrupt type.
 382  */
 383 unsigned int __do_IRQ(unsigned int irq)
 384 {
 385         struct irq_desc *desc = irq_to_desc(irq);
 386         struct irqaction *action;
 387         unsigned int status;
 388
 389 #ifdef CONFIG_HAVE_DYN_ARRAY
 390         kstat_irqs_this_cpu(desc)++;
 391 #else
 392         kstat_irqs_this_cpu(irq)++;
 393 #endif
 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 #ifdef CONFIG_HAVE_DYN_ARRAY
 494 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 495 {
 496         struct irq_desc *desc = irq_to_desc(irq);
 497         return desc->kstat_irqs[cpu];
 498 }
 499 #endif
 500 EXPORT_SYMBOL(kstat_irqs_cpu);
 501