git.maemo.org Git - h-e-n/blob - 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(irq_desc->lock),
 257 #ifdef CONFIG_SMP
 258                 .affinity = CPU_MASK_ALL
 259 #endif
 260         }
 261 };
 262
 263 #endif
 264
 265 /*
 266  * What should we do if we get a hw irq event on an illegal vector?
 267  * Each architecture has to answer this themself.
 268  */
 269 static void ack_bad(unsigned int irq)
 270 {
 271         struct irq_desc *desc;
 272
 273         desc = irq_to_desc(irq);
 274         print_irq_desc(irq, desc);
 275         ack_bad_irq(irq);
 276 }
 277
 278 /*
 279  * NOP functions
 280  */
 281 static void noop(unsigned int irq)
 282 {
 283 }
 284
 285 static unsigned int noop_ret(unsigned int irq)
 286 {
 287         return 0;
 288 }
 289
 290 /*
 291  * Generic no controller implementation
 292  */
 293 struct irq_chip no_irq_chip = {
 294         .name           = "none",
 295         .startup        = noop_ret,
 296         .shutdown       = noop,
 297         .enable         = noop,
 298         .disable        = noop,
 299         .ack            = ack_bad,
 300         .end            = noop,
 301 };
 302
 303 /*
 304  * Generic dummy implementation which can be used for
 305  * real dumb interrupt sources
 306  */
 307 struct irq_chip dummy_irq_chip = {
 308         .name           = "dummy",
 309         .startup        = noop_ret,
 310         .shutdown       = noop,
 311         .enable         = noop,
 312         .disable        = noop,
 313         .ack            = noop,
 314         .mask           = noop,
 315         .unmask         = noop,
 316         .end            = noop,
 317 };
 318
 319 /*
 320  * Special, empty irq handler:
 321  */
 322 irqreturn_t no_action(int cpl, void *dev_id)
 323 {
 324         return IRQ_NONE;
 325 }
 326
 327 /**
 328  * handle_IRQ_event - irq action chain handler
 329  * @irq:        the interrupt number
 330  * @action:     the interrupt action chain for this irq
 331  *
 332  * Handles the action chain of an irq event
 333  */
 334 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 335 {
 336         irqreturn_t ret, retval = IRQ_NONE;
 337         unsigned int status = 0;
 338
 339         if (!(action->flags & IRQF_DISABLED))
 340                 local_irq_enable_in_hardirq();
 341
 342         do {
 343                 ret = action->handler(irq, action->dev_id);
 344                 if (ret == IRQ_HANDLED)
 345                         status |= action->flags;
 346                 retval |= ret;
 347                 action = action->next;
 348         } while (action);
 349
 350         if (status & IRQF_SAMPLE_RANDOM)
 351                 add_interrupt_randomness(irq);
 352         local_irq_disable();
 353
 354         return retval;
 355 }
 356
 357 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 358 /**
 359  * __do_IRQ - original all in one highlevel IRQ handler
 360  * @irq:        the interrupt number
 361  *
 362  * __do_IRQ handles all normal device IRQ's (the special
 363  * SMP cross-CPU interrupts have their own specific
 364  * handlers).
 365  *
 366  * This is the original x86 implementation which is used for every
 367  * interrupt type.
 368  */
 369 unsigned int __do_IRQ(unsigned int irq)
 370 {
 371         struct irq_desc *desc = irq_to_desc(irq);
 372         struct irqaction *action;
 373         unsigned int status;
 374
 375 #ifdef CONFIG_HAVE_DYN_ARRAY
 376         kstat_irqs_this_cpu(desc)++;
 377 #else
 378         kstat_irqs_this_cpu(irq)++;
 379 #endif
 380         if (CHECK_IRQ_PER_CPU(desc->status)) {
 381                 irqreturn_t action_ret;
 382
 383                 /*
 384                  * No locking required for CPU-local interrupts:
 385                  */
 386                 if (desc->chip->ack)
 387                         desc->chip->ack(irq);
 388                 if (likely(!(desc->status & IRQ_DISABLED))) {
 389                         action_ret = handle_IRQ_event(irq, desc->action);
 390                         if (!noirqdebug)
 391                                 note_interrupt(irq, desc, action_ret);
 392                 }
 393                 desc->chip->end(irq);
 394                 return 1;
 395         }
 396
 397         spin_lock(&desc->lock);
 398         if (desc->chip->ack)
 399                 desc->chip->ack(irq);
 400         /*
 401          * REPLAY is when Linux resends an IRQ that was dropped earlier
 402          * WAITING is used by probe to mark irqs that are being tested
 403          */
 404         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 405         status |= IRQ_PENDING; /* we _want_ to handle it */
 406
 407         /*
 408          * If the IRQ is disabled for whatever reason, we cannot
 409          * use the action we have.
 410          */
 411         action = NULL;
 412         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 413                 action = desc->action;
 414                 status &= ~IRQ_PENDING; /* we commit to handling */
 415                 status |= IRQ_INPROGRESS; /* we are handling it */
 416         }
 417         desc->status = status;
 418
 419         /*
 420          * If there is no IRQ handler or it was disabled, exit early.
 421          * Since we set PENDING, if another processor is handling
 422          * a different instance of this same irq, the other processor
 423          * will take care of it.
 424          */
 425         if (unlikely(!action))
 426                 goto out;
 427
 428         /*
 429          * Edge triggered interrupts need to remember
 430          * pending events.
 431          * This applies to any hw interrupts that allow a second
 432          * instance of the same irq to arrive while we are in do_IRQ
 433          * or in the handler. But the code here only handles the _second_
 434          * instance of the irq, not the third or fourth. So it is mostly
 435          * useful for irq hardware that does not mask cleanly in an
 436          * SMP environment.
 437          */
 438         for (;;) {
 439                 irqreturn_t action_ret;
 440
 441                 spin_unlock(&desc->lock);
 442
 443                 action_ret = handle_IRQ_event(irq, action);
 444                 if (!noirqdebug)
 445                         note_interrupt(irq, desc, action_ret);
 446
 447                 spin_lock(&desc->lock);
 448                 if (likely(!(desc->status & IRQ_PENDING)))
 449                         break;
 450                 desc->status &= ~IRQ_PENDING;
 451         }
 452         desc->status &= ~IRQ_INPROGRESS;
 453
 454 out:
 455         /*
 456          * The ->end() handler has to deal with interrupts which got
 457          * disabled while the handler was running.
 458          */
 459         desc->chip->end(irq);
 460         spin_unlock(&desc->lock);
 461
 462         return 1;
 463 }
 464 #endif
 465
 466
 467 #ifdef CONFIG_TRACE_IRQFLAGS
 468 void early_init_irq_lock_class(void)
 469 {
 470 #ifndef CONFIG_HAVE_DYN_ARRAY
 471         int i;
 472
 473         for (i = 0; i < nr_irqs; i++)
 474                 lockdep_set_class(&irq_desc[i].lock, &irq_desc_lock_class);
 475 #endif
 476 }
 477 #endif
 478
 479 #ifdef CONFIG_HAVE_DYN_ARRAY
 480 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 481 {
 482         struct irq_desc *desc = irq_to_desc(irq);
 483         return desc->kstat_irqs[cpu];
 484 }
 485 #endif
 486 EXPORT_SYMBOL(kstat_irqs_cpu);
 487