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_this_cpu.irqs[irq]++;
  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 #ifdef CONFIG_HAVE_SPARSE_IRQ
  84 static int nr_irq_desc = 32;
  85
  86 static int __init parse_nr_irq_desc(char *arg)
  87 {
  88         if (arg)
  89                 nr_irq_desc = simple_strtoul(arg, NULL, 0);
  90         return 0;
  91 }
  92
  93 early_param("nr_irq_desc", parse_nr_irq_desc);
  94
  95 static void __init init_work(void *data)
  96 {
  97         struct dyn_array *da = data;
  98         int i;
  99         struct  irq_desc *desc;
 100
 101         desc = *da->name;
 102
 103         for (i = 0; i < *da->nr; i++)
 104                 init_one_irq_desc(&desc[i]);
 105
 106         for (i = 1; i < *da->nr; i++)
 107                 desc[i-1].next = &desc[i];
 108 }
 109
 110 static struct irq_desc *sparse_irqs;
 111 DEFINE_DYN_ARRAY(sparse_irqs, sizeof(struct irq_desc), nr_irq_desc, PAGE_SIZE, init_work);
 112
 113 extern int after_bootmem;
 114 extern void *__alloc_bootmem_nopanic(unsigned long size,
 115                              unsigned long align,
 116                              unsigned long goal);
 117 struct irq_desc *irq_to_desc(unsigned int irq)
 118 {
 119         struct irq_desc *desc, *desc_pri;
 120         int i;
 121         int count = 0;
 122
 123         BUG_ON(irq == -1U);
 124
 125         desc_pri = desc = &sparse_irqs[0];
 126         while (desc) {
 127                 if (desc->irq == irq)
 128                         return desc;
 129
 130                 if (desc->irq == -1U) {
 131                         desc->irq = irq;
 132                         return desc;
 133                 }
 134                 desc_pri = desc;
 135                 desc = desc->next;
 136                 count++;
 137         }
 138
 139         /*
 140          *  we run out of pre-allocate ones, allocate more
 141          */
 142         printk(KERN_DEBUG "try to get more irq_desc %d\n", nr_irq_desc);
 143
 144         if (after_bootmem)
 145                 desc = kzalloc(sizeof(struct irq_desc)*nr_irq_desc, GFP_ATOMIC);
 146         else
 147                 desc = __alloc_bootmem_nopanic(sizeof(struct irq_desc)*nr_irq_desc, PAGE_SIZE, 0);
 148
 149         if (!desc)
 150                 panic("please boot with nr_irq_desc= %d\n", count * 2);
 151
 152         for (i = 0; i < nr_irq_desc; i++)
 153                 init_one_irq_desc(&desc[i]);
 154
 155         for (i = 1; i < nr_irq_desc; i++)
 156                 desc[i-1].next = &desc[i];
 157
 158         desc->irq = irq;
 159         desc_pri->next = desc;
 160
 161         return desc;
 162 }
 163 #else
 164 static void __init init_work(void *data)
 165 {
 166         struct dyn_array *da = data;
 167         int i;
 168         struct  irq_desc *desc;
 169
 170         desc = *da->name;
 171
 172         for (i = 0; i < *da->nr; i++)
 173                 init_one_irq_desc(&desc[i]);
 174
 175 }
 176 static struct irq_desc *irq_desc;
 177 DEFINE_DYN_ARRAY(irq_desc, sizeof(struct irq_desc), nr_irqs, PAGE_SIZE, init_work);
 178
 179 #endif
 180
 181 #else
 182
 183 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 184         [0 ... NR_IRQS-1] = {
 185                 .status = IRQ_DISABLED,
 186                 .chip = &no_irq_chip,
 187                 .handle_irq = handle_bad_irq,
 188                 .depth = 1,
 189                 .lock = __SPIN_LOCK_UNLOCKED(sparse_irqs->lock),
 190 #ifdef CONFIG_SMP
 191                 .affinity = CPU_MASK_ALL
 192 #endif
 193         }
 194 };
 195
 196 #endif
 197
 198 #ifndef CONFIG_HAVE_SPARSE_IRQ
 199 struct irq_desc *irq_to_desc(unsigned int irq)
 200 {
 201         if (irq < nr_irqs)
 202                 return &irq_desc[irq];
 203
 204         return NULL;
 205 }
 206 #endif
 207
 208 /*
 209  * What should we do if we get a hw irq event on an illegal vector?
 210  * Each architecture has to answer this themself.
 211  */
 212 static void ack_bad(unsigned int irq)
 213 {
 214         struct irq_desc *desc;
 215
 216         desc = irq_to_desc(irq);
 217         print_irq_desc(irq, desc);
 218         ack_bad_irq(irq);
 219 }
 220
 221 /*
 222  * NOP functions
 223  */
 224 static void noop(unsigned int irq)
 225 {
 226 }
 227
 228 static unsigned int noop_ret(unsigned int irq)
 229 {
 230         return 0;
 231 }
 232
 233 /*
 234  * Generic no controller implementation
 235  */
 236 struct irq_chip no_irq_chip = {
 237         .name           = "none",
 238         .startup        = noop_ret,
 239         .shutdown       = noop,
 240         .enable         = noop,
 241         .disable        = noop,
 242         .ack            = ack_bad,
 243         .end            = noop,
 244 };
 245
 246 /*
 247  * Generic dummy implementation which can be used for
 248  * real dumb interrupt sources
 249  */
 250 struct irq_chip dummy_irq_chip = {
 251         .name           = "dummy",
 252         .startup        = noop_ret,
 253         .shutdown       = noop,
 254         .enable         = noop,
 255         .disable        = noop,
 256         .ack            = noop,
 257         .mask           = noop,
 258         .unmask         = noop,
 259         .end            = noop,
 260 };
 261
 262 /*
 263  * Special, empty irq handler:
 264  */
 265 irqreturn_t no_action(int cpl, void *dev_id)
 266 {
 267         return IRQ_NONE;
 268 }
 269
 270 /**
 271  * handle_IRQ_event - irq action chain handler
 272  * @irq:        the interrupt number
 273  * @action:     the interrupt action chain for this irq
 274  *
 275  * Handles the action chain of an irq event
 276  */
 277 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 278 {
 279         irqreturn_t ret, retval = IRQ_NONE;
 280         unsigned int status = 0;
 281
 282         if (!(action->flags & IRQF_DISABLED))
 283                 local_irq_enable_in_hardirq();
 284
 285         do {
 286                 ret = action->handler(irq, action->dev_id);
 287                 if (ret == IRQ_HANDLED)
 288                         status |= action->flags;
 289                 retval |= ret;
 290                 action = action->next;
 291         } while (action);
 292
 293         if (status & IRQF_SAMPLE_RANDOM)
 294                 add_interrupt_randomness(irq);
 295         local_irq_disable();
 296
 297         return retval;
 298 }
 299
 300 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 301 /**
 302  * __do_IRQ - original all in one highlevel IRQ handler
 303  * @irq:        the interrupt number
 304  *
 305  * __do_IRQ handles all normal device IRQ's (the special
 306  * SMP cross-CPU interrupts have their own specific
 307  * handlers).
 308  *
 309  * This is the original x86 implementation which is used for every
 310  * interrupt type.
 311  */
 312 unsigned int __do_IRQ(unsigned int irq)
 313 {
 314         struct irq_desc *desc = irq_to_desc(irq);
 315         struct irqaction *action;
 316         unsigned int status;
 317
 318         kstat_this_cpu.irqs[irq]++;
 319         if (CHECK_IRQ_PER_CPU(desc->status)) {
 320                 irqreturn_t action_ret;
 321
 322                 /*
 323                  * No locking required for CPU-local interrupts:
 324                  */
 325                 if (desc->chip->ack)
 326                         desc->chip->ack(irq);
 327                 if (likely(!(desc->status & IRQ_DISABLED))) {
 328                         action_ret = handle_IRQ_event(irq, desc->action);
 329                         if (!noirqdebug)
 330                                 note_interrupt(irq, desc, action_ret);
 331                 }
 332                 desc->chip->end(irq);
 333                 return 1;
 334         }
 335
 336         spin_lock(&desc->lock);
 337         if (desc->chip->ack)
 338                 desc->chip->ack(irq);
 339         /*
 340          * REPLAY is when Linux resends an IRQ that was dropped earlier
 341          * WAITING is used by probe to mark irqs that are being tested
 342          */
 343         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 344         status |= IRQ_PENDING; /* we _want_ to handle it */
 345
 346         /*
 347          * If the IRQ is disabled for whatever reason, we cannot
 348          * use the action we have.
 349          */
 350         action = NULL;
 351         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 352                 action = desc->action;
 353                 status &= ~IRQ_PENDING; /* we commit to handling */
 354                 status |= IRQ_INPROGRESS; /* we are handling it */
 355         }
 356         desc->status = status;
 357
 358         /*
 359          * If there is no IRQ handler or it was disabled, exit early.
 360          * Since we set PENDING, if another processor is handling
 361          * a different instance of this same irq, the other processor
 362          * will take care of it.
 363          */
 364         if (unlikely(!action))
 365                 goto out;
 366
 367         /*
 368          * Edge triggered interrupts need to remember
 369          * pending events.
 370          * This applies to any hw interrupts that allow a second
 371          * instance of the same irq to arrive while we are in do_IRQ
 372          * or in the handler. But the code here only handles the _second_
 373          * instance of the irq, not the third or fourth. So it is mostly
 374          * useful for irq hardware that does not mask cleanly in an
 375          * SMP environment.
 376          */
 377         for (;;) {
 378                 irqreturn_t action_ret;
 379
 380                 spin_unlock(&desc->lock);
 381
 382                 action_ret = handle_IRQ_event(irq, action);
 383                 if (!noirqdebug)
 384                         note_interrupt(irq, desc, action_ret);
 385
 386                 spin_lock(&desc->lock);
 387                 if (likely(!(desc->status & IRQ_PENDING)))
 388                         break;
 389                 desc->status &= ~IRQ_PENDING;
 390         }
 391         desc->status &= ~IRQ_INPROGRESS;
 392
 393 out:
 394         /*
 395          * The ->end() handler has to deal with interrupts which got
 396          * disabled while the handler was running.
 397          */
 398         desc->chip->end(irq);
 399         spin_unlock(&desc->lock);
 400
 401         return 1;
 402 }
 403 #endif
 404
 405
 406 #ifdef CONFIG_TRACE_IRQFLAGS
 407 void early_init_irq_lock_class(void)
 408 {
 409 #ifndef CONFIG_HAVE_DYN_ARRAY
 410         int i;
 411
 412         for (i = 0; i < nr_irqs; i++)
 413                 lockdep_set_class(&irq_desc[i].lock, &irq_desc_lock_class);
 414 #endif
 415 }
 416 #endif
 417