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