linux/include/linux/interrupt.h
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   1/* interrupt.h */
   2#ifndef _LINUX_INTERRUPT_H
   3#define _LINUX_INTERRUPT_H
   4
   5#include <linux/kernel.h>
   6#include <linux/linkage.h>
   7#include <linux/bitops.h>
   8#include <linux/preempt.h>
   9#include <linux/cpumask.h>
  10#include <linux/irqreturn.h>
  11#include <linux/irqnr.h>
  12#include <linux/hardirq.h>
  13#include <linux/irqflags.h>
  14#include <linux/smp.h>
  15#include <linux/percpu.h>
  16#include <linux/hrtimer.h>
  17#include <linux/kref.h>
  18#include <linux/workqueue.h>
  19
  20#include <linux/atomic.h>
  21#include <asm/ptrace.h>
  22
  23/*
  24 * These correspond to the IORESOURCE_IRQ_* defines in
  25 * linux/ioport.h to select the interrupt line behaviour.  When
  26 * requesting an interrupt without specifying a IRQF_TRIGGER, the
  27 * setting should be assumed to be "as already configured", which
  28 * may be as per machine or firmware initialisation.
  29 */
  30#define IRQF_TRIGGER_NONE       0x00000000
  31#define IRQF_TRIGGER_RISING     0x00000001
  32#define IRQF_TRIGGER_FALLING    0x00000002
  33#define IRQF_TRIGGER_HIGH       0x00000004
  34#define IRQF_TRIGGER_LOW        0x00000008
  35#define IRQF_TRIGGER_MASK       (IRQF_TRIGGER_HIGH | IRQF_TRIGGER_LOW | \
  36                                 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)
  37#define IRQF_TRIGGER_PROBE      0x00000010
  38
  39/*
  40 * These flags used only by the kernel as part of the
  41 * irq handling routines.
  42 *
  43 * IRQF_DISABLED - keep irqs disabled when calling the action handler.
  44 *                 DEPRECATED. This flag is a NOOP and scheduled to be removed
  45 * IRQF_SHARED - allow sharing the irq among several devices
  46 * IRQF_PROBE_SHARED - set by callers when they expect sharing mismatches to occur
  47 * IRQF_TIMER - Flag to mark this interrupt as timer interrupt
  48 * IRQF_PERCPU - Interrupt is per cpu
  49 * IRQF_NOBALANCING - Flag to exclude this interrupt from irq balancing
  50 * IRQF_IRQPOLL - Interrupt is used for polling (only the interrupt that is
  51 *                registered first in an shared interrupt is considered for
  52 *                performance reasons)
  53 * IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler finished.
  54 *                Used by threaded interrupts which need to keep the
  55 *                irq line disabled until the threaded handler has been run.
  56 * IRQF_NO_SUSPEND - Do not disable this IRQ during suspend
  57 * IRQF_FORCE_RESUME - Force enable it on resume even if IRQF_NO_SUSPEND is set
  58 * IRQF_NO_THREAD - Interrupt cannot be threaded
  59 * IRQF_EARLY_RESUME - Resume IRQ early during syscore instead of at device
  60 *                resume time.
  61 */
  62#define IRQF_DISABLED           0x00000020
  63#define IRQF_SHARED             0x00000080
  64#define IRQF_PROBE_SHARED       0x00000100
  65#define __IRQF_TIMER            0x00000200
  66#define IRQF_PERCPU             0x00000400
  67#define IRQF_NOBALANCING        0x00000800
  68#define IRQF_IRQPOLL            0x00001000
  69#define IRQF_ONESHOT            0x00002000
  70#define IRQF_NO_SUSPEND         0x00004000
  71#define IRQF_FORCE_RESUME       0x00008000
  72#define IRQF_NO_THREAD          0x00010000
  73#define IRQF_EARLY_RESUME       0x00020000
  74
  75#define IRQF_TIMER              (__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD)
  76
  77/*
  78 * These values can be returned by request_any_context_irq() and
  79 * describe the context the interrupt will be run in.
  80 *
  81 * IRQC_IS_HARDIRQ - interrupt runs in hardirq context
  82 * IRQC_IS_NESTED - interrupt runs in a nested threaded context
  83 */
  84enum {
  85        IRQC_IS_HARDIRQ = 0,
  86        IRQC_IS_NESTED,
  87};
  88
  89typedef irqreturn_t (*irq_handler_t)(int, void *);
  90
  91/**
  92 * struct irqaction - per interrupt action descriptor
  93 * @handler:    interrupt handler function
  94 * @name:       name of the device
  95 * @dev_id:     cookie to identify the device
  96 * @percpu_dev_id:      cookie to identify the device
  97 * @next:       pointer to the next irqaction for shared interrupts
  98 * @irq:        interrupt number
  99 * @flags:      flags (see IRQF_* above)
 100 * @thread_fn:  interrupt handler function for threaded interrupts
 101 * @thread:     thread pointer for threaded interrupts
 102 * @thread_flags:       flags related to @thread
 103 * @thread_mask:        bitmask for keeping track of @thread activity
 104 * @dir:        pointer to the proc/irq/NN/name entry
 105 */
 106struct irqaction {
 107        irq_handler_t           handler;
 108        void                    *dev_id;
 109        void __percpu           *percpu_dev_id;
 110        struct irqaction        *next;
 111        irq_handler_t           thread_fn;
 112        struct task_struct      *thread;
 113        unsigned int            irq;
 114        unsigned int            flags;
 115        unsigned long           thread_flags;
 116        unsigned long           thread_mask;
 117        const char              *name;
 118        struct proc_dir_entry   *dir;
 119} ____cacheline_internodealigned_in_smp;
 120
 121extern irqreturn_t no_action(int cpl, void *dev_id);
 122
 123#ifdef CONFIG_GENERIC_HARDIRQS
 124extern int __must_check
 125request_threaded_irq(unsigned int irq, irq_handler_t handler,
 126                     irq_handler_t thread_fn,
 127                     unsigned long flags, const char *name, void *dev);
 128
 129static inline int __must_check
 130request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,
 131            const char *name, void *dev)
 132{
 133        return request_threaded_irq(irq, handler, NULL, flags, name, dev);
 134}
 135
 136extern int __must_check
 137request_any_context_irq(unsigned int irq, irq_handler_t handler,
 138                        unsigned long flags, const char *name, void *dev_id);
 139
 140extern int __must_check
 141request_percpu_irq(unsigned int irq, irq_handler_t handler,
 142                   const char *devname, void __percpu *percpu_dev_id);
 143#else
 144
 145extern int __must_check
 146request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,
 147            const char *name, void *dev);
 148
 149/*
 150 * Special function to avoid ifdeffery in kernel/irq/devres.c which
 151 * gets magically built by GENERIC_HARDIRQS=n architectures (sparc,
 152 * m68k). I really love these $@%#!* obvious Makefile references:
 153 * ../../../kernel/irq/devres.o
 154 */
 155static inline int __must_check
 156request_threaded_irq(unsigned int irq, irq_handler_t handler,
 157                     irq_handler_t thread_fn,
 158                     unsigned long flags, const char *name, void *dev)
 159{
 160        return request_irq(irq, handler, flags, name, dev);
 161}
 162
 163static inline int __must_check
 164request_any_context_irq(unsigned int irq, irq_handler_t handler,
 165                        unsigned long flags, const char *name, void *dev_id)
 166{
 167        return request_irq(irq, handler, flags, name, dev_id);
 168}
 169
 170static inline int __must_check
 171request_percpu_irq(unsigned int irq, irq_handler_t handler,
 172                   const char *devname, void __percpu *percpu_dev_id)
 173{
 174        return request_irq(irq, handler, 0, devname, percpu_dev_id);
 175}
 176#endif
 177
 178extern void free_irq(unsigned int, void *);
 179extern void free_percpu_irq(unsigned int, void __percpu *);
 180
 181struct device;
 182
 183extern int __must_check
 184devm_request_threaded_irq(struct device *dev, unsigned int irq,
 185                          irq_handler_t handler, irq_handler_t thread_fn,
 186                          unsigned long irqflags, const char *devname,
 187                          void *dev_id);
 188
 189static inline int __must_check
 190devm_request_irq(struct device *dev, unsigned int irq, irq_handler_t handler,
 191                 unsigned long irqflags, const char *devname, void *dev_id)
 192{
 193        return devm_request_threaded_irq(dev, irq, handler, NULL, irqflags,
 194                                         devname, dev_id);
 195}
 196
 197extern void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id);
 198
 199/*
 200 * On lockdep we dont want to enable hardirqs in hardirq
 201 * context. Use local_irq_enable_in_hardirq() to annotate
 202 * kernel code that has to do this nevertheless (pretty much
 203 * the only valid case is for old/broken hardware that is
 204 * insanely slow).
 205 *
 206 * NOTE: in theory this might break fragile code that relies
 207 * on hardirq delivery - in practice we dont seem to have such
 208 * places left. So the only effect should be slightly increased
 209 * irqs-off latencies.
 210 */
 211#ifdef CONFIG_LOCKDEP
 212# define local_irq_enable_in_hardirq()  do { } while (0)
 213#else
 214# define local_irq_enable_in_hardirq()  local_irq_enable()
 215#endif
 216
 217extern void disable_irq_nosync(unsigned int irq);
 218extern void disable_irq(unsigned int irq);
 219extern void disable_percpu_irq(unsigned int irq);
 220extern void enable_irq(unsigned int irq);
 221extern void enable_percpu_irq(unsigned int irq, unsigned int type);
 222
 223/* The following three functions are for the core kernel use only. */
 224#ifdef CONFIG_GENERIC_HARDIRQS
 225extern void suspend_device_irqs(void);
 226extern void resume_device_irqs(void);
 227#ifdef CONFIG_PM_SLEEP
 228extern int check_wakeup_irqs(void);
 229#else
 230static inline int check_wakeup_irqs(void) { return 0; }
 231#endif
 232#else
 233static inline void suspend_device_irqs(void) { };
 234static inline void resume_device_irqs(void) { };
 235static inline int check_wakeup_irqs(void) { return 0; }
 236#endif
 237
 238#if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_HARDIRQS)
 239
 240extern cpumask_var_t irq_default_affinity;
 241
 242extern int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask);
 243extern int irq_can_set_affinity(unsigned int irq);
 244extern int irq_select_affinity(unsigned int irq);
 245
 246extern int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m);
 247
 248/**
 249 * struct irq_affinity_notify - context for notification of IRQ affinity changes
 250 * @irq:                Interrupt to which notification applies
 251 * @kref:               Reference count, for internal use
 252 * @work:               Work item, for internal use
 253 * @notify:             Function to be called on change.  This will be
 254 *                      called in process context.
 255 * @release:            Function to be called on release.  This will be
 256 *                      called in process context.  Once registered, the
 257 *                      structure must only be freed when this function is
 258 *                      called or later.
 259 */
 260struct irq_affinity_notify {
 261        unsigned int irq;
 262        struct kref kref;
 263        struct work_struct work;
 264        void (*notify)(struct irq_affinity_notify *, const cpumask_t *mask);
 265        void (*release)(struct kref *ref);
 266};
 267
 268extern int
 269irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify);
 270
 271static inline void irq_run_affinity_notifiers(void)
 272{
 273        flush_scheduled_work();
 274}
 275
 276#else /* CONFIG_SMP */
 277
 278static inline int irq_set_affinity(unsigned int irq, const struct cpumask *m)
 279{
 280        return -EINVAL;
 281}
 282
 283static inline int irq_can_set_affinity(unsigned int irq)
 284{
 285        return 0;
 286}
 287
 288static inline int irq_select_affinity(unsigned int irq)  { return 0; }
 289
 290static inline int irq_set_affinity_hint(unsigned int irq,
 291                                        const struct cpumask *m)
 292{
 293        return -EINVAL;
 294}
 295#endif /* CONFIG_SMP && CONFIG_GENERIC_HARDIRQS */
 296
 297#ifdef CONFIG_GENERIC_HARDIRQS
 298/*
 299 * Special lockdep variants of irq disabling/enabling.
 300 * These should be used for locking constructs that
 301 * know that a particular irq context which is disabled,
 302 * and which is the only irq-context user of a lock,
 303 * that it's safe to take the lock in the irq-disabled
 304 * section without disabling hardirqs.
 305 *
 306 * On !CONFIG_LOCKDEP they are equivalent to the normal
 307 * irq disable/enable methods.
 308 */
 309static inline void disable_irq_nosync_lockdep(unsigned int irq)
 310{
 311        disable_irq_nosync(irq);
 312#ifdef CONFIG_LOCKDEP
 313        local_irq_disable();
 314#endif
 315}
 316
 317static inline void disable_irq_nosync_lockdep_irqsave(unsigned int irq, unsigned long *flags)
 318{
 319        disable_irq_nosync(irq);
 320#ifdef CONFIG_LOCKDEP
 321        local_irq_save(*flags);
 322#endif
 323}
 324
 325static inline void disable_irq_lockdep(unsigned int irq)
 326{
 327        disable_irq(irq);
 328#ifdef CONFIG_LOCKDEP
 329        local_irq_disable();
 330#endif
 331}
 332
 333static inline void enable_irq_lockdep(unsigned int irq)
 334{
 335#ifdef CONFIG_LOCKDEP
 336        local_irq_enable();
 337#endif
 338        enable_irq(irq);
 339}
 340
 341static inline void enable_irq_lockdep_irqrestore(unsigned int irq, unsigned long *flags)
 342{
 343#ifdef CONFIG_LOCKDEP
 344        local_irq_restore(*flags);
 345#endif
 346        enable_irq(irq);
 347}
 348
 349/* IRQ wakeup (PM) control: */
 350extern int irq_set_irq_wake(unsigned int irq, unsigned int on);
 351
 352static inline int enable_irq_wake(unsigned int irq)
 353{
 354        return irq_set_irq_wake(irq, 1);
 355}
 356
 357static inline int disable_irq_wake(unsigned int irq)
 358{
 359        return irq_set_irq_wake(irq, 0);
 360}
 361
 362#else /* !CONFIG_GENERIC_HARDIRQS */
 363/*
 364 * NOTE: non-genirq architectures, if they want to support the lock
 365 * validator need to define the methods below in their asm/irq.h
 366 * files, under an #ifdef CONFIG_LOCKDEP section.
 367 */
 368#ifndef CONFIG_LOCKDEP
 369#  define disable_irq_nosync_lockdep(irq)       disable_irq_nosync(irq)
 370#  define disable_irq_nosync_lockdep_irqsave(irq, flags) \
 371                                                disable_irq_nosync(irq)
 372#  define disable_irq_lockdep(irq)              disable_irq(irq)
 373#  define enable_irq_lockdep(irq)               enable_irq(irq)
 374#  define enable_irq_lockdep_irqrestore(irq, flags) \
 375                                                enable_irq(irq)
 376# endif
 377
 378static inline int enable_irq_wake(unsigned int irq)
 379{
 380        return 0;
 381}
 382
 383static inline int disable_irq_wake(unsigned int irq)
 384{
 385        return 0;
 386}
 387#endif /* CONFIG_GENERIC_HARDIRQS */
 388
 389
 390#ifdef CONFIG_IRQ_FORCED_THREADING
 391extern bool force_irqthreads;
 392#else
 393#define force_irqthreads        (0)
 394#endif
 395
 396#ifndef __ARCH_SET_SOFTIRQ_PENDING
 397#define set_softirq_pending(x) (local_softirq_pending() = (x))
 398#define or_softirq_pending(x)  (local_softirq_pending() |= (x))
 399#endif
 400
 401/* Some architectures might implement lazy enabling/disabling of
 402 * interrupts. In some cases, such as stop_machine, we might want
 403 * to ensure that after a local_irq_disable(), interrupts have
 404 * really been disabled in hardware. Such architectures need to
 405 * implement the following hook.
 406 */
 407#ifndef hard_irq_disable
 408#define hard_irq_disable()      do { } while(0)
 409#endif
 410
 411/* PLEASE, avoid to allocate new softirqs, if you need not _really_ high
 412   frequency threaded job scheduling. For almost all the purposes
 413   tasklets are more than enough. F.e. all serial device BHs et
 414   al. should be converted to tasklets, not to softirqs.
 415 */
 416
 417enum
 418{
 419        HI_SOFTIRQ=0,
 420        TIMER_SOFTIRQ,
 421        NET_TX_SOFTIRQ,
 422        NET_RX_SOFTIRQ,
 423        BLOCK_SOFTIRQ,
 424        BLOCK_IOPOLL_SOFTIRQ,
 425        TASKLET_SOFTIRQ,
 426        SCHED_SOFTIRQ,
 427        HRTIMER_SOFTIRQ,
 428        RCU_SOFTIRQ,    /* Preferable RCU should always be the last softirq */
 429
 430        NR_SOFTIRQS
 431};
 432
 433/* map softirq index to softirq name. update 'softirq_to_name' in
 434 * kernel/softirq.c when adding a new softirq.
 435 */
 436extern char *softirq_to_name[NR_SOFTIRQS];
 437
 438/* softirq mask and active fields moved to irq_cpustat_t in
 439 * asm/hardirq.h to get better cache usage.  KAO
 440 */
 441
 442struct softirq_action
 443{
 444        void    (*action)(struct softirq_action *);
 445};
 446
 447asmlinkage void do_softirq(void);
 448asmlinkage void __do_softirq(void);
 449extern void open_softirq(int nr, void (*action)(struct softirq_action *));
 450extern void softirq_init(void);
 451extern void __raise_softirq_irqoff(unsigned int nr);
 452
 453extern void raise_softirq_irqoff(unsigned int nr);
 454extern void raise_softirq(unsigned int nr);
 455
 456/* This is the worklist that queues up per-cpu softirq work.
 457 *
 458 * send_remote_sendirq() adds work to these lists, and
 459 * the softirq handler itself dequeues from them.  The queues
 460 * are protected by disabling local cpu interrupts and they must
 461 * only be accessed by the local cpu that they are for.
 462 */
 463DECLARE_PER_CPU(struct list_head [NR_SOFTIRQS], softirq_work_list);
 464
 465DECLARE_PER_CPU(struct task_struct *, ksoftirqd);
 466
 467static inline struct task_struct *this_cpu_ksoftirqd(void)
 468{
 469        return this_cpu_read(ksoftirqd);
 470}
 471
 472/* Try to send a softirq to a remote cpu.  If this cannot be done, the
 473 * work will be queued to the local cpu.
 474 */
 475extern void send_remote_softirq(struct call_single_data *cp, int cpu, int softirq);
 476
 477/* Like send_remote_softirq(), but the caller must disable local cpu interrupts
 478 * and compute the current cpu, passed in as 'this_cpu'.
 479 */
 480extern void __send_remote_softirq(struct call_single_data *cp, int cpu,
 481                                  int this_cpu, int softirq);
 482
 483/* Tasklets --- multithreaded analogue of BHs.
 484
 485   Main feature differing them of generic softirqs: tasklet
 486   is running only on one CPU simultaneously.
 487
 488   Main feature differing them of BHs: different tasklets
 489   may be run simultaneously on different CPUs.
 490
 491   Properties:
 492   * If tasklet_schedule() is called, then tasklet is guaranteed
 493     to be executed on some cpu at least once after this.
 494   * If the tasklet is already scheduled, but its execution is still not
 495     started, it will be executed only once.
 496   * If this tasklet is already running on another CPU (or schedule is called
 497     from tasklet itself), it is rescheduled for later.
 498   * Tasklet is strictly serialized wrt itself, but not
 499     wrt another tasklets. If client needs some intertask synchronization,
 500     he makes it with spinlocks.
 501 */
 502
 503struct tasklet_struct
 504{
 505        struct tasklet_struct *next;
 506        unsigned long state;
 507        atomic_t count;
 508        void (*func)(unsigned long);
 509        unsigned long data;
 510};
 511
 512#define DECLARE_TASKLET(name, func, data) \
 513struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(0), func, data }
 514
 515#define DECLARE_TASKLET_DISABLED(name, func, data) \
 516struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(1), func, data }
 517
 518
 519enum
 520{
 521        TASKLET_STATE_SCHED,    /* Tasklet is scheduled for execution */
 522        TASKLET_STATE_RUN       /* Tasklet is running (SMP only) */
 523};
 524
 525#ifdef CONFIG_SMP
 526static inline int tasklet_trylock(struct tasklet_struct *t)
 527{
 528        return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state);
 529}
 530
 531static inline void tasklet_unlock(struct tasklet_struct *t)
 532{
 533        smp_mb__before_clear_bit(); 
 534        clear_bit(TASKLET_STATE_RUN, &(t)->state);
 535}
 536
 537static inline void tasklet_unlock_wait(struct tasklet_struct *t)
 538{
 539        while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
 540}
 541#else
 542#define tasklet_trylock(t) 1
 543#define tasklet_unlock_wait(t) do { } while (0)
 544#define tasklet_unlock(t) do { } while (0)
 545#endif
 546
 547extern void __tasklet_schedule(struct tasklet_struct *t);
 548
 549static inline void tasklet_schedule(struct tasklet_struct *t)
 550{
 551        if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
 552                __tasklet_schedule(t);
 553}
 554
 555extern void __tasklet_hi_schedule(struct tasklet_struct *t);
 556
 557static inline void tasklet_hi_schedule(struct tasklet_struct *t)
 558{
 559        if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
 560                __tasklet_hi_schedule(t);
 561}
 562
 563extern void __tasklet_hi_schedule_first(struct tasklet_struct *t);
 564
 565/*
 566 * This version avoids touching any other tasklets. Needed for kmemcheck
 567 * in order not to take any page faults while enqueueing this tasklet;
 568 * consider VERY carefully whether you really need this or
 569 * tasklet_hi_schedule()...
 570 */
 571static inline void tasklet_hi_schedule_first(struct tasklet_struct *t)
 572{
 573        if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
 574                __tasklet_hi_schedule_first(t);
 575}
 576
 577
 578static inline void tasklet_disable_nosync(struct tasklet_struct *t)
 579{
 580        atomic_inc(&t->count);
 581        smp_mb__after_atomic_inc();
 582}
 583
 584static inline void tasklet_disable(struct tasklet_struct *t)
 585{
 586        tasklet_disable_nosync(t);
 587        tasklet_unlock_wait(t);
 588        smp_mb();
 589}
 590
 591static inline void tasklet_enable(struct tasklet_struct *t)
 592{
 593        smp_mb__before_atomic_dec();
 594        atomic_dec(&t->count);
 595}
 596
 597static inline void tasklet_hi_enable(struct tasklet_struct *t)
 598{
 599        smp_mb__before_atomic_dec();
 600        atomic_dec(&t->count);
 601}
 602
 603extern void tasklet_kill(struct tasklet_struct *t);
 604extern void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu);
 605extern void tasklet_init(struct tasklet_struct *t,
 606                         void (*func)(unsigned long), unsigned long data);
 607
 608struct tasklet_hrtimer {
 609        struct hrtimer          timer;
 610        struct tasklet_struct   tasklet;
 611        enum hrtimer_restart    (*function)(struct hrtimer *);
 612};
 613
 614extern void
 615tasklet_hrtimer_init(struct tasklet_hrtimer *ttimer,
 616                     enum hrtimer_restart (*function)(struct hrtimer *),
 617                     clockid_t which_clock, enum hrtimer_mode mode);
 618
 619static inline
 620int tasklet_hrtimer_start(struct tasklet_hrtimer *ttimer, ktime_t time,
 621                          const enum hrtimer_mode mode)
 622{
 623        return hrtimer_start(&ttimer->timer, time, mode);
 624}
 625
 626static inline
 627void tasklet_hrtimer_cancel(struct tasklet_hrtimer *ttimer)
 628{
 629        hrtimer_cancel(&ttimer->timer);
 630        tasklet_kill(&ttimer->tasklet);
 631}
 632
 633/*
 634 * Autoprobing for irqs:
 635 *
 636 * probe_irq_on() and probe_irq_off() provide robust primitives
 637 * for accurate IRQ probing during kernel initialization.  They are
 638 * reasonably simple to use, are not "fooled" by spurious interrupts,
 639 * and, unlike other attempts at IRQ probing, they do not get hung on
 640 * stuck interrupts (such as unused PS2 mouse interfaces on ASUS boards).
 641 *
 642 * For reasonably foolproof probing, use them as follows:
 643 *
 644 * 1. clear and/or mask the device's internal interrupt.
 645 * 2. sti();
 646 * 3. irqs = probe_irq_on();      // "take over" all unassigned idle IRQs
 647 * 4. enable the device and cause it to trigger an interrupt.
 648 * 5. wait for the device to interrupt, using non-intrusive polling or a delay.
 649 * 6. irq = probe_irq_off(irqs);  // get IRQ number, 0=none, negative=multiple
 650 * 7. service the device to clear its pending interrupt.
 651 * 8. loop again if paranoia is required.
 652 *
 653 * probe_irq_on() returns a mask of allocated irq's.
 654 *
 655 * probe_irq_off() takes the mask as a parameter,
 656 * and returns the irq number which occurred,
 657 * or zero if none occurred, or a negative irq number
 658 * if more than one irq occurred.
 659 */
 660
 661#if defined(CONFIG_GENERIC_HARDIRQS) && !defined(CONFIG_GENERIC_IRQ_PROBE) 
 662static inline unsigned long probe_irq_on(void)
 663{
 664        return 0;
 665}
 666static inline int probe_irq_off(unsigned long val)
 667{
 668        return 0;
 669}
 670static inline unsigned int probe_irq_mask(unsigned long val)
 671{
 672        return 0;
 673}
 674#else
 675extern unsigned long probe_irq_on(void);        /* returns 0 on failure */
 676extern int probe_irq_off(unsigned long);        /* returns 0 or negative on failure */
 677extern unsigned int probe_irq_mask(unsigned long);      /* returns mask of ISA interrupts */
 678#endif
 679
 680#ifdef CONFIG_PROC_FS
 681/* Initialize /proc/irq/ */
 682extern void init_irq_proc(void);
 683#else
 684static inline void init_irq_proc(void)
 685{
 686}
 687#endif
 688
 689struct seq_file;
 690int show_interrupts(struct seq_file *p, void *v);
 691int arch_show_interrupts(struct seq_file *p, int prec);
 692
 693extern int early_irq_init(void);
 694extern int arch_probe_nr_irqs(void);
 695extern int arch_early_irq_init(void);
 696
 697#endif
 698
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