linux/include/linux/clockchips.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*  linux/include/linux/clockchips.h
   3 *
   4 *  This file contains the structure definitions for clockchips.
   5 *
   6 *  If you are not a clockchip, or the time of day code, you should
   7 *  not be including this file!
   8 */
   9#ifndef _LINUX_CLOCKCHIPS_H
  10#define _LINUX_CLOCKCHIPS_H
  11
  12#ifdef CONFIG_GENERIC_CLOCKEVENTS
  13
  14# include <linux/clocksource.h>
  15# include <linux/cpumask.h>
  16# include <linux/ktime.h>
  17# include <linux/notifier.h>
  18
  19struct clock_event_device;
  20struct module;
  21
  22/*
  23 * Possible states of a clock event device.
  24 *
  25 * DETACHED:    Device is not used by clockevents core. Initial state or can be
  26 *              reached from SHUTDOWN.
  27 * SHUTDOWN:    Device is powered-off. Can be reached from PERIODIC or ONESHOT.
  28 * PERIODIC:    Device is programmed to generate events periodically. Can be
  29 *              reached from DETACHED or SHUTDOWN.
  30 * ONESHOT:     Device is programmed to generate event only once. Can be reached
  31 *              from DETACHED or SHUTDOWN.
  32 * ONESHOT_STOPPED: Device was programmed in ONESHOT mode and is temporarily
  33 *                  stopped.
  34 */
  35enum clock_event_state {
  36        CLOCK_EVT_STATE_DETACHED,
  37        CLOCK_EVT_STATE_SHUTDOWN,
  38        CLOCK_EVT_STATE_PERIODIC,
  39        CLOCK_EVT_STATE_ONESHOT,
  40        CLOCK_EVT_STATE_ONESHOT_STOPPED,
  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/*
  51 * x86(64) specific (mis)features:
  52 *
  53 * - Clockevent source stops in C3 State and needs broadcast support.
  54 * - Local APIC timer is used as a dummy device.
  55 */
  56# define CLOCK_EVT_FEAT_C3STOP          0x000008
  57# define CLOCK_EVT_FEAT_DUMMY           0x000010
  58
  59/*
  60 * Core shall set the interrupt affinity dynamically in broadcast mode
  61 */
  62# define CLOCK_EVT_FEAT_DYNIRQ          0x000020
  63# define CLOCK_EVT_FEAT_PERCPU          0x000040
  64
  65/*
  66 * Clockevent device is based on a hrtimer for broadcast
  67 */
  68# define CLOCK_EVT_FEAT_HRTIMER         0x000080
  69
  70/**
  71 * struct clock_event_device - clock event device descriptor
  72 * @event_handler:      Assigned by the framework to be called by the low
  73 *                      level handler of the event source
  74 * @set_next_event:     set next event function using a clocksource delta
  75 * @set_next_ktime:     set next event function using a direct ktime value
  76 * @next_event:         local storage for the next event in oneshot mode
  77 * @max_delta_ns:       maximum delta value in ns
  78 * @min_delta_ns:       minimum delta value in ns
  79 * @mult:               nanosecond to cycles multiplier
  80 * @shift:              nanoseconds to cycles divisor (power of two)
  81 * @state_use_accessors:current state of the device, assigned by the core code
  82 * @features:           features
  83 * @retries:            number of forced programming retries
  84 * @set_state_periodic: switch state to periodic
  85 * @set_state_oneshot:  switch state to oneshot
  86 * @set_state_oneshot_stopped: switch state to oneshot_stopped
  87 * @set_state_shutdown: switch state to shutdown
  88 * @tick_resume:        resume clkevt device
  89 * @broadcast:          function to broadcast events
  90 * @min_delta_ticks:    minimum delta value in ticks stored for reconfiguration
  91 * @max_delta_ticks:    maximum delta value in ticks stored for reconfiguration
  92 * @name:               ptr to clock event name
  93 * @rating:             variable to rate clock event devices
  94 * @irq:                IRQ number (only for non CPU local devices)
  95 * @bound_on:           Bound on CPU
  96 * @cpumask:            cpumask to indicate for which CPUs this device works
  97 * @list:               list head for the management code
  98 * @owner:              module reference
  99 */
 100struct clock_event_device {
 101        void                    (*event_handler)(struct clock_event_device *);
 102        int                     (*set_next_event)(unsigned long evt, struct clock_event_device *);
 103        int                     (*set_next_ktime)(ktime_t expires, struct clock_event_device *);
 104        ktime_t                 next_event;
 105        u64                     max_delta_ns;
 106        u64                     min_delta_ns;
 107        u32                     mult;
 108        u32                     shift;
 109        enum clock_event_state  state_use_accessors;
 110        unsigned int            features;
 111        unsigned long           retries;
 112
 113        int                     (*set_state_periodic)(struct clock_event_device *);
 114        int                     (*set_state_oneshot)(struct clock_event_device *);
 115        int                     (*set_state_oneshot_stopped)(struct clock_event_device *);
 116        int                     (*set_state_shutdown)(struct clock_event_device *);
 117        int                     (*tick_resume)(struct clock_event_device *);
 118
 119        void                    (*broadcast)(const struct cpumask *mask);
 120        void                    (*suspend)(struct clock_event_device *);
 121        void                    (*resume)(struct clock_event_device *);
 122        unsigned long           min_delta_ticks;
 123        unsigned long           max_delta_ticks;
 124
 125        const char              *name;
 126        int                     rating;
 127        int                     irq;
 128        int                     bound_on;
 129        const struct cpumask    *cpumask;
 130        struct list_head        list;
 131        struct module           *owner;
 132} ____cacheline_aligned;
 133
 134/* Helpers to verify state of a clockevent device */
 135static inline bool clockevent_state_detached(struct clock_event_device *dev)
 136{
 137        return dev->state_use_accessors == CLOCK_EVT_STATE_DETACHED;
 138}
 139
 140static inline bool clockevent_state_shutdown(struct clock_event_device *dev)
 141{
 142        return dev->state_use_accessors == CLOCK_EVT_STATE_SHUTDOWN;
 143}
 144
 145static inline bool clockevent_state_periodic(struct clock_event_device *dev)
 146{
 147        return dev->state_use_accessors == CLOCK_EVT_STATE_PERIODIC;
 148}
 149
 150static inline bool clockevent_state_oneshot(struct clock_event_device *dev)
 151{
 152        return dev->state_use_accessors == CLOCK_EVT_STATE_ONESHOT;
 153}
 154
 155static inline bool clockevent_state_oneshot_stopped(struct clock_event_device *dev)
 156{
 157        return dev->state_use_accessors == CLOCK_EVT_STATE_ONESHOT_STOPPED;
 158}
 159
 160/*
 161 * Calculate a multiplication factor for scaled math, which is used to convert
 162 * nanoseconds based values to clock ticks:
 163 *
 164 * clock_ticks = (nanoseconds * factor) >> shift.
 165 *
 166 * div_sc is the rearranged equation to calculate a factor from a given clock
 167 * ticks / nanoseconds ratio:
 168 *
 169 * factor = (clock_ticks << shift) / nanoseconds
 170 */
 171static inline unsigned long
 172div_sc(unsigned long ticks, unsigned long nsec, int shift)
 173{
 174        u64 tmp = ((u64)ticks) << shift;
 175
 176        do_div(tmp, nsec);
 177
 178        return (unsigned long) tmp;
 179}
 180
 181/* Clock event layer functions */
 182extern u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt);
 183extern void clockevents_register_device(struct clock_event_device *dev);
 184extern int clockevents_unbind_device(struct clock_event_device *ced, int cpu);
 185
 186extern void clockevents_config_and_register(struct clock_event_device *dev,
 187                                            u32 freq, unsigned long min_delta,
 188                                            unsigned long max_delta);
 189
 190extern int clockevents_update_freq(struct clock_event_device *ce, u32 freq);
 191
 192static inline void
 193clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 maxsec)
 194{
 195        return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC, freq, maxsec);
 196}
 197
 198extern void clockevents_suspend(void);
 199extern void clockevents_resume(void);
 200
 201# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 202#  ifdef CONFIG_ARCH_HAS_TICK_BROADCAST
 203extern void tick_broadcast(const struct cpumask *mask);
 204#  else
 205#   define tick_broadcast       NULL
 206#  endif
 207extern int tick_receive_broadcast(void);
 208# endif
 209
 210# if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
 211extern void tick_setup_hrtimer_broadcast(void);
 212extern int tick_check_broadcast_expired(void);
 213# else
 214static inline int tick_check_broadcast_expired(void) { return 0; }
 215static inline void tick_setup_hrtimer_broadcast(void) { }
 216# endif
 217
 218#else /* !CONFIG_GENERIC_CLOCKEVENTS: */
 219
 220static inline void clockevents_suspend(void) { }
 221static inline void clockevents_resume(void) { }
 222static inline int tick_check_broadcast_expired(void) { return 0; }
 223static inline void tick_setup_hrtimer_broadcast(void) { }
 224
 225#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 226
 227#endif /* _LINUX_CLOCKCHIPS_H */
 228
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