linux/include/linux/clockchips.h
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   1/*  linux/include/linux/clockchips.h
   2 *
   3 *  This file contains the structure definitions for clockchips.
   4 *
   5 *  If you are not a clockchip, or the time of day code, you should
   6 *  not be including this file!
   7 */
   8#ifndef _LINUX_CLOCKCHIPS_H
   9#define _LINUX_CLOCKCHIPS_H
  10
  11#ifdef CONFIG_GENERIC_CLOCKEVENTS_BUILD
  12
  13#include <linux/clocksource.h>
  14#include <linux/cpumask.h>
  15#include <linux/ktime.h>
  16#include <linux/notifier.h>
  17
  18struct clock_event_device;
  19
  20/* Clock event mode commands */
  21enum clock_event_mode {
  22        CLOCK_EVT_MODE_UNUSED = 0,
  23        CLOCK_EVT_MODE_SHUTDOWN,
  24        CLOCK_EVT_MODE_PERIODIC,
  25        CLOCK_EVT_MODE_ONESHOT,
  26        CLOCK_EVT_MODE_RESUME,
  27};
  28
  29/* Clock event notification values */
  30enum clock_event_nofitiers {
  31        CLOCK_EVT_NOTIFY_ADD,
  32        CLOCK_EVT_NOTIFY_BROADCAST_ON,
  33        CLOCK_EVT_NOTIFY_BROADCAST_OFF,
  34        CLOCK_EVT_NOTIFY_BROADCAST_FORCE,
  35        CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
  36        CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
  37        CLOCK_EVT_NOTIFY_SUSPEND,
  38        CLOCK_EVT_NOTIFY_RESUME,
  39        CLOCK_EVT_NOTIFY_CPU_DYING,
  40        CLOCK_EVT_NOTIFY_CPU_DEAD,
  41};
  42
  43/*
  44 * Clock event features
  45 */
  46#define CLOCK_EVT_FEAT_PERIODIC         0x000001
  47#define CLOCK_EVT_FEAT_ONESHOT          0x000002
  48/*
  49 * x86(64) specific misfeatures:
  50 *
  51 * - Clockevent source stops in C3 State and needs broadcast support.
  52 * - Local APIC timer is used as a dummy device.
  53 */
  54#define CLOCK_EVT_FEAT_C3STOP           0x000004
  55#define CLOCK_EVT_FEAT_DUMMY            0x000008
  56
  57/**
  58 * struct clock_event_device - clock event device descriptor
  59 * @name:               ptr to clock event name
  60 * @features:           features
  61 * @max_delta_ns:       maximum delta value in ns
  62 * @min_delta_ns:       minimum delta value in ns
  63 * @mult:               nanosecond to cycles multiplier
  64 * @shift:              nanoseconds to cycles divisor (power of two)
  65 * @rating:             variable to rate clock event devices
  66 * @irq:                IRQ number (only for non CPU local devices)
  67 * @cpumask:            cpumask to indicate for which CPUs this device works
  68 * @set_next_event:     set next event function
  69 * @set_mode:           set mode function
  70 * @event_handler:      Assigned by the framework to be called by the low
  71 *                      level handler of the event source
  72 * @broadcast:          function to broadcast events
  73 * @list:               list head for the management code
  74 * @mode:               operating mode assigned by the management code
  75 * @next_event:         local storage for the next event in oneshot mode
  76 * @retries:            number of forced programming retries
  77 */
  78struct clock_event_device {
  79        const char              *name;
  80        unsigned int            features;
  81        u64                     max_delta_ns;
  82        u64                     min_delta_ns;
  83        u32                     mult;
  84        u32                     shift;
  85        int                     rating;
  86        int                     irq;
  87        const struct cpumask    *cpumask;
  88        int                     (*set_next_event)(unsigned long evt,
  89                                                  struct clock_event_device *);
  90        void                    (*set_mode)(enum clock_event_mode mode,
  91                                            struct clock_event_device *);
  92        void                    (*event_handler)(struct clock_event_device *);
  93        void                    (*broadcast)(const struct cpumask *mask);
  94        struct list_head        list;
  95        enum clock_event_mode   mode;
  96        ktime_t                 next_event;
  97        unsigned long           retries;
  98};
  99
 100/*
 101 * Calculate a multiplication factor for scaled math, which is used to convert
 102 * nanoseconds based values to clock ticks:
 103 *
 104 * clock_ticks = (nanoseconds * factor) >> shift.
 105 *
 106 * div_sc is the rearranged equation to calculate a factor from a given clock
 107 * ticks / nanoseconds ratio:
 108 *
 109 * factor = (clock_ticks << shift) / nanoseconds
 110 */
 111static inline unsigned long div_sc(unsigned long ticks, unsigned long nsec,
 112                                   int shift)
 113{
 114        uint64_t tmp = ((uint64_t)ticks) << shift;
 115
 116        do_div(tmp, nsec);
 117        return (unsigned long) tmp;
 118}
 119
 120/* Clock event layer functions */
 121extern u64 clockevent_delta2ns(unsigned long latch,
 122                               struct clock_event_device *evt);
 123extern void clockevents_register_device(struct clock_event_device *dev);
 124
 125extern void clockevents_exchange_device(struct clock_event_device *old,
 126                                        struct clock_event_device *new);
 127extern void clockevents_set_mode(struct clock_event_device *dev,
 128                                 enum clock_event_mode mode);
 129extern int clockevents_register_notifier(struct notifier_block *nb);
 130extern int clockevents_program_event(struct clock_event_device *dev,
 131                                     ktime_t expires, ktime_t now);
 132
 133extern void clockevents_handle_noop(struct clock_event_device *dev);
 134
 135static inline void
 136clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 minsec)
 137{
 138        return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC,
 139                                      freq, minsec);
 140}
 141
 142#ifdef CONFIG_GENERIC_CLOCKEVENTS
 143extern void clockevents_notify(unsigned long reason, void *arg);
 144#else
 145# define clockevents_notify(reason, arg) do { } while (0)
 146#endif
 147
 148#else /* CONFIG_GENERIC_CLOCKEVENTS_BUILD */
 149
 150#define clockevents_notify(reason, arg) do { } while (0)
 151
 152#endif
 153
 154#endif
 155