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 /*
 111  * Protect the sparse_irqs_free freelist:
 112  */
 113 static DEFINE_SPINLOCK(sparse_irq_lock);
 114
 115 #ifdef CONFIG_HAVE_SPARSE_IRQ
 116 static struct irq_desc *sparse_irqs_free;
 117 struct irq_desc *sparse_irqs;
 118 #endif
 119
 120 static void __init init_work(void *data)
 121 {
 122         struct dyn_array *da = data;
 123         int i;
 124         struct  irq_desc *desc;
 125
 126         desc = *da->name;
 127
 128         for (i = 0; i < *da->nr; i++) {
 129                 init_one_irq_desc(&desc[i]);
 130 #ifndef CONFIG_HAVE_SPARSE_IRQ
 131                 desc[i].irq = i;
 132 #endif
 133         }
 134
 135         /* init kstat_irqs, nr_cpu_ids is ready already */
 136         init_kstat_irqs(desc, *da->nr, nr_cpu_ids);
 137
 138 #ifdef CONFIG_HAVE_SPARSE_IRQ
 139         for (i = 1; i < *da->nr; i++)
 140                 desc[i-1].next = &desc[i];
 141
 142         sparse_irqs_free = sparse_irqs;
 143         sparse_irqs = NULL;
 144 #endif
 145 }
 146
 147 #ifdef CONFIG_HAVE_SPARSE_IRQ
 148 static int nr_irq_desc = 32;
 149
 150 static int __init parse_nr_irq_desc(char *arg)
 151 {
 152         if (arg)
 153                 nr_irq_desc = simple_strtoul(arg, NULL, 0);
 154         return 0;
 155 }
 156
 157 early_param("nr_irq_desc", parse_nr_irq_desc);
 158
 159 DEFINE_DYN_ARRAY(sparse_irqs, sizeof(struct irq_desc), nr_irq_desc, PAGE_SIZE, init_work);
 160
 161 struct irq_desc *irq_to_desc(unsigned int irq)
 162 {
 163         struct irq_desc *desc;
 164
 165         desc = sparse_irqs;
 166         while (desc) {
 167                 if (desc->irq == irq)
 168                         return desc;
 169
 170                 desc = desc->next;
 171         }
 172         return NULL;
 173 }
 174
 175 struct irq_desc *irq_to_desc_alloc(unsigned int irq)
 176 {
 177         struct irq_desc *desc, *desc_pri;
 178         unsigned long flags;
 179         int count = 0;
 180         int i;
 181
 182         desc_pri = desc = sparse_irqs;
 183         while (desc) {
 184                 if (desc->irq == irq)
 185                         return desc;
 186
 187                 desc_pri = desc;
 188                 desc = desc->next;
 189                 count++;
 190         }
 191
 192         spin_lock_irqsave(&sparse_irq_lock, flags);
 193         /*
 194          *  we run out of pre-allocate ones, allocate more
 195          */
 196         if (!sparse_irqs_free) {
 197                 unsigned long phys;
 198                 unsigned long total_bytes;
 199
 200                 printk(KERN_DEBUG "try to get more irq_desc %d\n", nr_irq_desc);
 201
 202                 total_bytes = sizeof(struct irq_desc) * nr_irq_desc;
 203                 if (after_bootmem)
 204                         desc = kzalloc(total_bytes, GFP_ATOMIC);
 205                 else
 206                         desc = __alloc_bootmem_nopanic(total_bytes, PAGE_SIZE, 0);
 207
 208                 if (!desc)
 209                         panic("please boot with nr_irq_desc= %d\n", count * 2);
 210
 211                 phys = __pa(desc);
 212                 printk(KERN_DEBUG "irq_desc ==> [%#lx - %#lx]\n", phys, phys + total_bytes);
 213
 214                 for (i = 0; i < nr_irq_desc; i++)
 215                         init_one_irq_desc(&desc[i]);
 216
 217                 for (i = 1; i < nr_irq_desc; i++)
 218                         desc[i-1].next = &desc[i];
 219
 220                 /* init kstat_irqs, nr_cpu_ids is ready already */
 221                 init_kstat_irqs(desc, nr_irq_desc, nr_cpu_ids);
 222
 223                 sparse_irqs_free = desc;
 224         }
 225
 226         desc = sparse_irqs_free;
 227         sparse_irqs_free = sparse_irqs_free->next;
 228         desc->next = NULL;
 229         if (desc_pri)
 230                 desc_pri->next = desc;
 231         else
 232                 sparse_irqs = desc;
 233         desc->irq = irq;
 234
 235         spin_unlock_irqrestore(&sparse_irq_lock, flags);
 236
 237         printk(KERN_DEBUG "found new irq_desc for irq %d\n", desc->irq);
 238 #ifdef CONFIG_HAVE_SPARSE_IRQ_DEBUG
 239         {
 240                 /* dump the results */
 241                 struct irq_desc *desc;
 242                 unsigned long phys;
 243                 unsigned long bytes = sizeof(struct irq_desc);
 244                 unsigned int irqx;
 245
 246                 printk(KERN_DEBUG "=========================== %d\n", irq);
 247                 printk(KERN_DEBUG "irq_desc dump after get that for %d\n", irq);
 248                 for_each_irq_desc(irqx, desc) {
 249                         phys = __pa(desc);
 250                         printk(KERN_DEBUG "irq_desc %d ==> [%#lx - %#lx]\n", irqx, phys, phys + bytes);
 251                 }
 252                 printk(KERN_DEBUG "===========================\n");
 253         }
 254 #endif
 255         return desc;
 256 }
 257 #else
 258 struct irq_desc *irq_desc;
 259 DEFINE_DYN_ARRAY(irq_desc, sizeof(struct irq_desc), nr_irqs, PAGE_SIZE, init_work);
 260
 261 #endif
 262
 263 #else
 264
 265 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 266         [0 ... NR_IRQS-1] = {
 267                 .status = IRQ_DISABLED,
 268                 .chip = &no_irq_chip,
 269                 .handle_irq = handle_bad_irq,
 270                 .depth = 1,
 271                 .lock = __SPIN_LOCK_UNLOCKED(sparse_irqs->lock),
 272 #ifdef CONFIG_SMP
 273                 .affinity = CPU_MASK_ALL
 274 #endif
 275         }
 276 };
 277
 278 #endif
 279
 280 #ifndef CONFIG_HAVE_SPARSE_IRQ
 281 struct irq_desc *irq_to_desc(unsigned int irq)
 282 {
 283         if (irq < nr_irqs)
 284                 return &irq_desc[irq];
 285
 286         return NULL;
 287 }
 288 struct irq_desc *irq_to_desc_alloc(unsigned int irq)
 289 {
 290         return irq_to_desc(irq);
 291 }
 292 #endif
 293
 294 /*
 295  * What should we do if we get a hw irq event on an illegal vector?
 296  * Each architecture has to answer this themself.
 297  */
 298 static void ack_bad(unsigned int irq)
 299 {
 300         struct irq_desc *desc;
 301
 302         desc = irq_to_desc(irq);
 303         print_irq_desc(irq, desc);
 304         ack_bad_irq(irq);
 305 }
 306
 307 /*
 308  * NOP functions
 309  */
 310 static void noop(unsigned int irq)
 311 {
 312 }
 313
 314 static unsigned int noop_ret(unsigned int irq)
 315 {
 316         return 0;
 317 }
 318
 319 /*
 320  * Generic no controller implementation
 321  */
 322 struct irq_chip no_irq_chip = {
 323         .name           = "none",
 324         .startup        = noop_ret,
 325         .shutdown       = noop,
 326         .enable         = noop,
 327         .disable        = noop,
 328         .ack            = ack_bad,
 329         .end            = noop,
 330 };
 331
 332 /*
 333  * Generic dummy implementation which can be used for
 334  * real dumb interrupt sources
 335  */
 336 struct irq_chip dummy_irq_chip = {
 337         .name           = "dummy",
 338         .startup        = noop_ret,
 339         .shutdown       = noop,
 340         .enable         = noop,
 341         .disable        = noop,
 342         .ack            = noop,
 343         .mask           = noop,
 344         .unmask         = noop,
 345         .end            = noop,
 346 };
 347
 348 /*
 349  * Special, empty irq handler:
 350  */
 351 irqreturn_t no_action(int cpl, void *dev_id)
 352 {
 353         return IRQ_NONE;
 354 }
 355
 356 /**
 357  * handle_IRQ_event - irq action chain handler
 358  * @irq:        the interrupt number
 359  * @action:     the interrupt action chain for this irq
 360  *
 361  * Handles the action chain of an irq event
 362  */
 363 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 364 {
 365         irqreturn_t ret, retval = IRQ_NONE;
 366         unsigned int status = 0;
 367
 368         if (!(action->flags & IRQF_DISABLED))
 369                 local_irq_enable_in_hardirq();
 370
 371         do {
 372                 ret = action->handler(irq, action->dev_id);
 373                 if (ret == IRQ_HANDLED)
 374                         status |= action->flags;
 375                 retval |= ret;
 376                 action = action->next;
 377         } while (action);
 378
 379         if (status & IRQF_SAMPLE_RANDOM)
 380                 add_interrupt_randomness(irq);
 381         local_irq_disable();
 382
 383         return retval;
 384 }
 385
 386 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 387 /**
 388  * __do_IRQ - original all in one highlevel IRQ handler
 389  * @irq:        the interrupt number
 390  *
 391  * __do_IRQ handles all normal device IRQ's (the special
 392  * SMP cross-CPU interrupts have their own specific
 393  * handlers).
 394  *
 395  * This is the original x86 implementation which is used for every
 396  * interrupt type.
 397  */
 398 unsigned int __do_IRQ(unsigned int irq)
 399 {
 400         struct irq_desc *desc = irq_to_desc(irq);
 401         struct irqaction *action;
 402         unsigned int status;
 403
 404         kstat_irqs_this_cpu(desc)++;
 405         if (CHECK_IRQ_PER_CPU(desc->status)) {
 406                 irqreturn_t action_ret;
 407
 408                 /*
 409                  * No locking required for CPU-local interrupts:
 410                  */
 411                 if (desc->chip->ack)
 412                         desc->chip->ack(irq);
 413                 if (likely(!(desc->status & IRQ_DISABLED))) {
 414                         action_ret = handle_IRQ_event(irq, desc->action);
 415                         if (!noirqdebug)
 416                                 note_interrupt(irq, desc, action_ret);
 417                 }
 418                 desc->chip->end(irq);
 419                 return 1;
 420         }
 421
 422         spin_lock(&desc->lock);
 423         if (desc->chip->ack)
 424                 desc->chip->ack(irq);
 425         /*
 426          * REPLAY is when Linux resends an IRQ that was dropped earlier
 427          * WAITING is used by probe to mark irqs that are being tested
 428          */
 429         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 430         status |= IRQ_PENDING; /* we _want_ to handle it */
 431
 432         /*
 433          * If the IRQ is disabled for whatever reason, we cannot
 434          * use the action we have.
 435          */
 436         action = NULL;
 437         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 438                 action = desc->action;
 439                 status &= ~IRQ_PENDING; /* we commit to handling */
 440                 status |= IRQ_INPROGRESS; /* we are handling it */
 441         }
 442         desc->status = status;
 443
 444         /*
 445          * If there is no IRQ handler or it was disabled, exit early.
 446          * Since we set PENDING, if another processor is handling
 447          * a different instance of this same irq, the other processor
 448          * will take care of it.
 449          */
 450         if (unlikely(!action))
 451                 goto out;
 452
 453         /*
 454          * Edge triggered interrupts need to remember
 455          * pending events.
 456          * This applies to any hw interrupts that allow a second
 457          * instance of the same irq to arrive while we are in do_IRQ
 458          * or in the handler. But the code here only handles the _second_
 459          * instance of the irq, not the third or fourth. So it is mostly
 460          * useful for irq hardware that does not mask cleanly in an
 461          * SMP environment.
 462          */
 463         for (;;) {
 464                 irqreturn_t action_ret;
 465
 466                 spin_unlock(&desc->lock);
 467
 468                 action_ret = handle_IRQ_event(irq, action);
 469                 if (!noirqdebug)
 470                         note_interrupt(irq, desc, action_ret);
 471
 472                 spin_lock(&desc->lock);
 473                 if (likely(!(desc->status & IRQ_PENDING)))
 474                         break;
 475                 desc->status &= ~IRQ_PENDING;
 476         }
 477         desc->status &= ~IRQ_INPROGRESS;
 478
 479 out:
 480         /*
 481          * The ->end() handler has to deal with interrupts which got
 482          * disabled while the handler was running.
 483          */
 484         desc->chip->end(irq);
 485         spin_unlock(&desc->lock);
 486
 487         return 1;
 488 }
 489 #endif
 490
 491
 492 #ifdef CONFIG_TRACE_IRQFLAGS
 493 void early_init_irq_lock_class(void)
 494 {
 495 #ifndef CONFIG_HAVE_DYN_ARRAY
 496         int i;
 497
 498         for (i = 0; i < nr_irqs; i++)
 499                 lockdep_set_class(&irq_desc[i].lock, &irq_desc_lock_class);
 500 #endif
 501 }
 502 #endif
 503
 504 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 505 {
 506         struct irq_desc *desc = irq_to_desc(irq);
 507         return desc->kstat_irqs[cpu];
 508 }
 509 EXPORT_SYMBOL(kstat_irqs_cpu);
 510