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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 /*
  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 /*
 115  * Protect the sparse_irqs_free freelist:
 116  */
 117 static DEFINE_SPINLOCK(sparse_irq_lock);
 118
 119 #ifdef CONFIG_HAVE_SPARSE_IRQ
 120 static struct irq_desc *sparse_irqs_free;
 121 struct irq_desc *sparse_irqs;
 122 #endif
 123
 124 static void __init init_work(void *data)
 125 {
 126         struct dyn_array *da = data;
 127         int i;
 128         struct  irq_desc *desc;
 129
 130         desc = *da->name;
 131
 132         for (i = 0; i < *da->nr; i++) {
 133                 init_one_irq_desc(&desc[i]);
 134 #ifndef CONFIG_HAVE_SPARSE_IRQ
 135                 desc[i].irq = i;
 136 #endif
 137         }
 138
 139         /* init kstat_irqs, nr_cpu_ids is ready already */
 140         init_kstat_irqs(desc, *da->nr, nr_cpu_ids);
 141
 142 #ifdef CONFIG_HAVE_SPARSE_IRQ
 143         for (i = 1; i < *da->nr; i++)
 144                 desc[i-1].next = &desc[i];
 145
 146         sparse_irqs_free = sparse_irqs;
 147         sparse_irqs = NULL;
 148 #endif
 149 }
 150
 151 #ifdef CONFIG_HAVE_SPARSE_IRQ
 152 static int nr_irq_desc = 32;
 153
 154 static int __init parse_nr_irq_desc(char *arg)
 155 {
 156         if (arg)
 157                 nr_irq_desc = simple_strtoul(arg, NULL, 0);
 158         return 0;
 159 }
 160
 161 early_param("nr_irq_desc", parse_nr_irq_desc);
 162
 163 DEFINE_DYN_ARRAY(sparse_irqs, sizeof(struct irq_desc), nr_irq_desc, PAGE_SIZE, init_work);
 164
 165 struct irq_desc *irq_to_desc(unsigned int irq)
 166 {
 167         struct irq_desc *desc;
 168
 169         desc = sparse_irqs;
 170         while (desc) {
 171                 if (desc->irq == irq)
 172                         return desc;
 173
 174                 desc = desc->next;
 175         }
 176         return NULL;
 177 }
 178
 179 struct irq_desc *irq_to_desc_alloc(unsigned int irq)
 180 {
 181         struct irq_desc *desc, *desc_pri;
 182         unsigned long flags;
 183         int count = 0;
 184         int i;
 185
 186         desc_pri = desc = sparse_irqs;
 187         while (desc) {
 188                 if (desc->irq == irq)
 189                         return desc;
 190
 191                 desc_pri = desc;
 192                 desc = desc->next;
 193                 count++;
 194         }
 195
 196         spin_lock_irqsave(&sparse_irq_lock, flags);
 197         /*
 198          *  we run out of pre-allocate ones, allocate more
 199          */
 200         if (!sparse_irqs_free) {
 201                 unsigned long phys;
 202                 unsigned long total_bytes;
 203
 204                 printk(KERN_DEBUG "try to get more irq_desc %d\n", nr_irq_desc);
 205
 206                 total_bytes = sizeof(struct irq_desc) * nr_irq_desc;
 207                 if (after_bootmem)
 208                         desc = kzalloc(total_bytes, GFP_ATOMIC);
 209                 else
 210                         desc = __alloc_bootmem_nopanic(total_bytes, PAGE_SIZE, 0);
 211
 212                 if (!desc)
 213                         panic("please boot with nr_irq_desc= %d\n", count * 2);
 214
 215                 phys = __pa(desc);
 216                 printk(KERN_DEBUG "irq_desc ==> [%#lx - %#lx]\n", phys, phys + total_bytes);
 217
 218                 for (i = 0; i < nr_irq_desc; i++)
 219                         init_one_irq_desc(&desc[i]);
 220
 221                 for (i = 1; i < nr_irq_desc; i++)
 222                         desc[i-1].next = &desc[i];
 223
 224                 /* init kstat_irqs, nr_cpu_ids is ready already */
 225                 init_kstat_irqs(desc, nr_irq_desc, nr_cpu_ids);
 226
 227                 sparse_irqs_free = desc;
 228         }
 229
 230         desc = sparse_irqs_free;
 231         sparse_irqs_free = sparse_irqs_free->next;
 232         desc->next = NULL;
 233         if (desc_pri)
 234                 desc_pri->next = desc;
 235         else
 236                 sparse_irqs = desc;
 237         desc->irq = irq;
 238
 239         spin_unlock_irqrestore(&sparse_irq_lock, flags);
 240
 241         printk(KERN_DEBUG "found new irq_desc for irq %d\n", desc->irq);
 242 #ifdef CONFIG_HAVE_SPARSE_IRQ_DEBUG
 243         {
 244                 /* dump the results */
 245                 struct irq_desc *desc;
 246                 unsigned long phys;
 247                 unsigned long bytes = sizeof(struct irq_desc);
 248                 unsigned int irqx;
 249
 250                 printk(KERN_DEBUG "=========================== %d\n", irq);
 251                 printk(KERN_DEBUG "irq_desc dump after get that for %d\n", irq);
 252                 for_each_irq_desc(irqx, desc) {
 253                         phys = __pa(desc);
 254                         printk(KERN_DEBUG "irq_desc %d ==> [%#lx - %#lx]\n", irqx, phys, phys + bytes);
 255                 }
 256                 printk(KERN_DEBUG "===========================\n");
 257         }
 258 #endif
 259         return desc;
 260 }
 261 #else
 262 struct irq_desc *irq_desc;
 263 DEFINE_DYN_ARRAY(irq_desc, sizeof(struct irq_desc), nr_irqs, PAGE_SIZE, init_work);
 264
 265 #endif
 266
 267 #else
 268
 269 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 270         [0 ... NR_IRQS-1] = {
 271                 .status = IRQ_DISABLED,
 272                 .chip = &no_irq_chip,
 273                 .handle_irq = handle_bad_irq,
 274                 .depth = 1,
 275                 .lock = __SPIN_LOCK_UNLOCKED(sparse_irqs->lock),
 276 #ifdef CONFIG_SMP
 277                 .affinity = CPU_MASK_ALL
 278 #endif
 279         }
 280 };
 281
 282 #endif
 283
 284 #ifndef CONFIG_HAVE_SPARSE_IRQ
 285 struct irq_desc *irq_to_desc(unsigned int irq)
 286 {
 287         if (irq < nr_irqs)
 288                 return &irq_desc[irq];
 289
 290         return NULL;
 291 }
 292 struct irq_desc *irq_to_desc_alloc(unsigned int irq)
 293 {
 294         return irq_to_desc(irq);
 295 }
 296 #endif
 297
 298 /*
 299  * What should we do if we get a hw irq event on an illegal vector?
 300  * Each architecture has to answer this themself.
 301  */
 302 static void ack_bad(unsigned int irq)
 303 {
 304         struct irq_desc *desc;
 305
 306         desc = irq_to_desc(irq);
 307         print_irq_desc(irq, desc);
 308         ack_bad_irq(irq);
 309 }
 310
 311 /*
 312  * NOP functions
 313  */
 314 static void noop(unsigned int irq)
 315 {
 316 }
 317
 318 static unsigned int noop_ret(unsigned int irq)
 319 {
 320         return 0;
 321 }
 322
 323 /*
 324  * Generic no controller implementation
 325  */
 326 struct irq_chip no_irq_chip = {
 327         .name           = "none",
 328         .startup        = noop_ret,
 329         .shutdown       = noop,
 330         .enable         = noop,
 331         .disable        = noop,
 332         .ack            = ack_bad,
 333         .end            = noop,
 334 };
 335
 336 /*
 337  * Generic dummy implementation which can be used for
 338  * real dumb interrupt sources
 339  */
 340 struct irq_chip dummy_irq_chip = {
 341         .name           = "dummy",
 342         .startup        = noop_ret,
 343         .shutdown       = noop,
 344         .enable         = noop,
 345         .disable        = noop,
 346         .ack            = noop,
 347         .mask           = noop,
 348         .unmask         = noop,
 349         .end            = noop,
 350 };
 351
 352 /*
 353  * Special, empty irq handler:
 354  */
 355 irqreturn_t no_action(int cpl, void *dev_id)
 356 {
 357         return IRQ_NONE;
 358 }
 359
 360 /**
 361  * handle_IRQ_event - irq action chain handler
 362  * @irq:        the interrupt number
 363  * @action:     the interrupt action chain for this irq
 364  *
 365  * Handles the action chain of an irq event
 366  */
 367 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 368 {
 369         irqreturn_t ret, retval = IRQ_NONE;
 370         unsigned int status = 0;
 371
 372         if (!(action->flags & IRQF_DISABLED))
 373                 local_irq_enable_in_hardirq();
 374
 375         do {
 376                 ret = action->handler(irq, action->dev_id);
 377                 if (ret == IRQ_HANDLED)
 378                         status |= action->flags;
 379                 retval |= ret;
 380                 action = action->next;
 381         } while (action);
 382
 383         if (status & IRQF_SAMPLE_RANDOM)
 384                 add_interrupt_randomness(irq);
 385         local_irq_disable();
 386
 387         return retval;
 388 }
 389
 390 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 391 /**
 392  * __do_IRQ - original all in one highlevel IRQ handler
 393  * @irq:        the interrupt number
 394  *
 395  * __do_IRQ handles all normal device IRQ's (the special
 396  * SMP cross-CPU interrupts have their own specific
 397  * handlers).
 398  *
 399  * This is the original x86 implementation which is used for every
 400  * interrupt type.
 401  */
 402 unsigned int __do_IRQ(unsigned int irq)
 403 {
 404         struct irq_desc *desc = irq_to_desc(irq);
 405         struct irqaction *action;
 406         unsigned int status;
 407
 408 #ifdef CONFIG_HAVE_DYN_ARRAY
 409         kstat_irqs_this_cpu(desc)++;
 410 #else
 411         kstat_irqs_this_cpu(irq)++;
 412 #endif
 413         if (CHECK_IRQ_PER_CPU(desc->status)) {
 414                 irqreturn_t action_ret;
 415
 416                 /*
 417                  * No locking required for CPU-local interrupts:
 418                  */
 419                 if (desc->chip->ack)
 420                         desc->chip->ack(irq);
 421                 if (likely(!(desc->status & IRQ_DISABLED))) {
 422                         action_ret = handle_IRQ_event(irq, desc->action);
 423                         if (!noirqdebug)
 424                                 note_interrupt(irq, desc, action_ret);
 425                 }
 426                 desc->chip->end(irq);
 427                 return 1;
 428         }
 429
 430         spin_lock(&desc->lock);
 431         if (desc->chip->ack)
 432                 desc->chip->ack(irq);
 433         /*
 434          * REPLAY is when Linux resends an IRQ that was dropped earlier
 435          * WAITING is used by probe to mark irqs that are being tested
 436          */
 437         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 438         status |= IRQ_PENDING; /* we _want_ to handle it */
 439
 440         /*
 441          * If the IRQ is disabled for whatever reason, we cannot
 442          * use the action we have.
 443          */
 444         action = NULL;
 445         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 446                 action = desc->action;
 447                 status &= ~IRQ_PENDING; /* we commit to handling */
 448                 status |= IRQ_INPROGRESS; /* we are handling it */
 449         }
 450         desc->status = status;
 451
 452         /*
 453          * If there is no IRQ handler or it was disabled, exit early.
 454          * Since we set PENDING, if another processor is handling
 455          * a different instance of this same irq, the other processor
 456          * will take care of it.
 457          */
 458         if (unlikely(!action))
 459                 goto out;
 460
 461         /*
 462          * Edge triggered interrupts need to remember
 463          * pending events.
 464          * This applies to any hw interrupts that allow a second
 465          * instance of the same irq to arrive while we are in do_IRQ
 466          * or in the handler. But the code here only handles the _second_
 467          * instance of the irq, not the third or fourth. So it is mostly
 468          * useful for irq hardware that does not mask cleanly in an
 469          * SMP environment.
 470          */
 471         for (;;) {
 472                 irqreturn_t action_ret;
 473
 474                 spin_unlock(&desc->lock);
 475
 476                 action_ret = handle_IRQ_event(irq, action);
 477                 if (!noirqdebug)
 478                         note_interrupt(irq, desc, action_ret);
 479
 480                 spin_lock(&desc->lock);
 481                 if (likely(!(desc->status & IRQ_PENDING)))
 482                         break;
 483                 desc->status &= ~IRQ_PENDING;
 484         }
 485         desc->status &= ~IRQ_INPROGRESS;
 486
 487 out:
 488         /*
 489          * The ->end() handler has to deal with interrupts which got
 490          * disabled while the handler was running.
 491          */
 492         desc->chip->end(irq);
 493         spin_unlock(&desc->lock);
 494
 495         return 1;
 496 }
 497 #endif
 498
 499
 500 #ifdef CONFIG_TRACE_IRQFLAGS
 501 void early_init_irq_lock_class(void)
 502 {
 503 #ifndef CONFIG_HAVE_DYN_ARRAY
 504         int i;
 505
 506         for (i = 0; i < nr_irqs; i++)
 507                 lockdep_set_class(&irq_desc[i].lock, &irq_desc_lock_class);
 508 #endif
 509 }
 510 #endif
 511
 512 #ifdef CONFIG_HAVE_DYN_ARRAY
 513 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 514 {
 515         struct irq_desc *desc = irq_to_desc(irq);
 516         return desc->kstat_irqs[cpu];
 517 }
 518 #endif
 519 EXPORT_SYMBOL(kstat_irqs_cpu);
 520