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