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