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#define CLOCK_EVT_FEAT_KTIME            0x000004
  49/*
  50 * x86(64) specific misfeatures:
  51 *
  52 * - Clockevent source stops in C3 State and needs broadcast support.
  53 * - Local APIC timer is used as a dummy device.
  54 */
  55#define CLOCK_EVT_FEAT_C3STOP           0x000008
  56#define CLOCK_EVT_FEAT_DUMMY            0x000010
  57
  58/**
  59 * struct clock_event_device - clock event device descriptor
  60 * @event_handler:      Assigned by the framework to be called by the low
  61 *                      level handler of the event source
  62 * @set_next_event:     set next event function using a clocksource delta
  63 * @set_next_ktime:     set next event function using a direct ktime value
  64 * @next_event:         local storage for the next event in oneshot mode
  65 * @max_delta_ns:       maximum delta value in ns
  66 * @min_delta_ns:       minimum delta value in ns
  67 * @mult:               nanosecond to cycles multiplier
  68 * @shift:              nanoseconds to cycles divisor (power of two)
  69 * @mode:               operating mode assigned by the management code
  70 * @features:           features
  71 * @retries:            number of forced programming retries
  72 * @set_mode:           set mode function
  73 * @broadcast:          function to broadcast events
  74 * @min_delta_ticks:    minimum delta value in ticks stored for reconfiguration
  75 * @max_delta_ticks:    maximum delta value in ticks stored for reconfiguration
  76 * @name:               ptr to clock event name
  77 * @rating:             variable to rate clock event devices
  78 * @irq:                IRQ number (only for non CPU local devices)
  79 * @cpumask:            cpumask to indicate for which CPUs this device works
  80 * @list:               list head for the management code
  81 */
  82struct clock_event_device {
  83        void                    (*event_handler)(struct clock_event_device *);
  84        int                     (*set_next_event)(unsigned long evt,
  85                                                  struct clock_event_device *);
  86        int                     (*set_next_ktime)(ktime_t expires,
  87                                                  struct clock_event_device *);
  88        ktime_t                 next_event;
  89        u64                     max_delta_ns;
  90        u64                     min_delta_ns;
  91        u32                     mult;
  92        u32                     shift;
  93        enum clock_event_mode   mode;
  94        unsigned int            features;
  95        unsigned long           retries;
  96
  97        void                    (*broadcast)(const struct cpumask *mask);
  98        void                    (*set_mode)(enum clock_event_mode mode,
  99                                            struct clock_event_device *);
 100        unsigned long           min_delta_ticks;
 101        unsigned long           max_delta_ticks;
 102
 103        const char              *name;
 104        int                     rating;
 105        int                     irq;
 106        const struct cpumask    *cpumask;
 107        struct list_head        list;
 108} ____cacheline_aligned;
 109
 110/*
 111 * Calculate a multiplication factor for scaled math, which is used to convert
 112 * nanoseconds based values to clock ticks:
 113 *
 114 * clock_ticks = (nanoseconds * factor) >> shift.
 115 *
 116 * div_sc is the rearranged equation to calculate a factor from a given clock
 117 * ticks / nanoseconds ratio:
 118 *
 119 * factor = (clock_ticks << shift) / nanoseconds
 120 */
 121static inline unsigned long div_sc(unsigned long ticks, unsigned long nsec,
 122                                   int shift)
 123{
 124        uint64_t tmp = ((uint64_t)ticks) << shift;
 125
 126        do_div(tmp, nsec);
 127        return (unsigned long) tmp;
 128}
 129
 130/* Clock event layer functions */
 131extern u64 clockevent_delta2ns(unsigned long latch,
 132                               struct clock_event_device *evt);
 133extern void clockevents_register_device(struct clock_event_device *dev);
 134
 135extern void clockevents_config(struct clock_event_device *dev, u32 freq);
 136extern void clockevents_config_and_register(struct clock_event_device *dev,
 137                                            u32 freq, unsigned long min_delta,
 138                                            unsigned long max_delta);
 139
 140extern int clockevents_update_freq(struct clock_event_device *ce, u32 freq);
 141
 142extern void clockevents_exchange_device(struct clock_event_device *old,
 143                                        struct clock_event_device *new);
 144extern void clockevents_set_mode(struct clock_event_device *dev,
 145                                 enum clock_event_mode mode);
 146extern int clockevents_register_notifier(struct notifier_block *nb);
 147extern int clockevents_program_event(struct clock_event_device *dev,
 148                                     ktime_t expires, bool force);
 149
 150extern void clockevents_handle_noop(struct clock_event_device *dev);
 151
 152static inline void
 153clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 minsec)
 154{
 155        return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC,
 156                                      freq, minsec);
 157}
 158
 159#ifdef CONFIG_GENERIC_CLOCKEVENTS
 160extern void clockevents_notify(unsigned long reason, void *arg);
 161#else
 162# define clockevents_notify(reason, arg) do { } while (0)
 163#endif
 164
 165#else /* CONFIG_GENERIC_CLOCKEVENTS_BUILD */
 166
 167#define clockevents_notify(reason, arg) do { } while (0)
 168
 169#endif
 170
 171#endif
 172
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