LXR linux/include/linux/clockchips.h

   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
  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;
  19struct module;
  20
  21/*
  22 * Possible states of a clock event device.
  23 *
  24 * DETACHED:    Device is not used by clockevents core. Initial state or can be
  25 *              reached from SHUTDOWN.
  26 * SHUTDOWN:    Device is powered-off. Can be reached from PERIODIC or ONESHOT.
  27 * PERIODIC:    Device is programmed to generate events periodically. Can be
  28 *              reached from DETACHED or SHUTDOWN.
  29 * ONESHOT:     Device is programmed to generate event only once. Can be reached
  30 *              from DETACHED or SHUTDOWN.
  31 * ONESHOT_STOPPED: Device was programmed in ONESHOT mode and is temporarily
  32 *                  stopped.
  33 */
  34enum clock_event_state {
  35        CLOCK_EVT_STATE_DETACHED,
  36        CLOCK_EVT_STATE_SHUTDOWN,
  37        CLOCK_EVT_STATE_PERIODIC,
  38        CLOCK_EVT_STATE_ONESHOT,
  39        CLOCK_EVT_STATE_ONESHOT_STOPPED,
  40};
  41
  42/*
  43 * Clock event features
  44 */
  45# define CLOCK_EVT_FEAT_PERIODIC        0x000001
  46# define CLOCK_EVT_FEAT_ONESHOT         0x000002
  47# define CLOCK_EVT_FEAT_KTIME           0x000004
  48
  49/*
  50 * x86(64) specific (mis)features:
  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 * Core shall set the interrupt affinity dynamically in broadcast mode
  60 */
  61# define CLOCK_EVT_FEAT_DYNIRQ          0x000020
  62# define CLOCK_EVT_FEAT_PERCPU          0x000040
  63
  64/*
  65 * Clockevent device is based on a hrtimer for broadcast
  66 */
  67# define CLOCK_EVT_FEAT_HRTIMER         0x000080
  68
  69/**
  70 * struct clock_event_device - clock event device descriptor
  71 * @event_handler:      Assigned by the framework to be called by the low
  72 *                      level handler of the event source
  73 * @set_next_event:     set next event function using a clocksource delta
  74 * @set_next_ktime:     set next event function using a direct ktime value
  75 * @next_event:         local storage for the next event in oneshot mode
  76 * @max_delta_ns:       maximum delta value in ns
  77 * @min_delta_ns:       minimum delta value in ns
  78 * @mult:               nanosecond to cycles multiplier
  79 * @shift:              nanoseconds to cycles divisor (power of two)
  80 * @state_use_accessors:current state of the device, assigned by the core code
  81 * @features:           features
  82 * @retries:            number of forced programming retries
  83 * @set_state_periodic: switch state to periodic
  84 * @set_state_oneshot:  switch state to oneshot
  85 * @set_state_oneshot_stopped: switch state to oneshot_stopped
  86 * @set_state_shutdown: switch state to shutdown
  87 * @tick_resume:        resume clkevt device
  88 * @broadcast:          function to broadcast events
  89 * @min_delta_ticks:    minimum delta value in ticks stored for reconfiguration
  90 * @max_delta_ticks:    maximum delta value in ticks stored for reconfiguration
  91 * @name:               ptr to clock event name
  92 * @rating:             variable to rate clock event devices
  93 * @irq:                IRQ number (only for non CPU local devices)
  94 * @bound_on:           Bound on CPU
  95 * @cpumask:            cpumask to indicate for which CPUs this device works
  96 * @list:               list head for the management code
  97 * @owner:              module reference
  98 */
  99struct clock_event_device {
 100        void                    (*event_handler)(struct clock_event_device *);
 101        int                     (*set_next_event)(unsigned long evt, struct clock_event_device *);
 102        int                     (*set_next_ktime)(ktime_t expires, struct clock_event_device *);
 103        ktime_t                 next_event;
 104        u64                     max_delta_ns;
 105        u64                     min_delta_ns;
 106        u32                     mult;
 107        u32                     shift;
 108        enum clock_event_state  state_use_accessors;
 109        unsigned int            features;
 110        unsigned long           retries;
 111
 112        int                     (*set_state_periodic)(struct clock_event_device *);
 113        int                     (*set_state_oneshot)(struct clock_event_device *);
 114        int                     (*set_state_oneshot_stopped)(struct clock_event_device *);
 115        int                     (*set_state_shutdown)(struct clock_event_device *);
 116        int                     (*tick_resume)(struct clock_event_device *);
 117
 118        void                    (*broadcast)(const struct cpumask *mask);
 119        void                    (*suspend)(struct clock_event_device *);
 120        void                    (*resume)(struct clock_event_device *);
 121        unsigned long           min_delta_ticks;
 122        unsigned long           max_delta_ticks;
 123
 124        const char              *name;
 125        int                     rating;
 126        int                     irq;
 127        int                     bound_on;
 128        const struct cpumask    *cpumask;
 129        struct list_head        list;
 130        struct module           *owner;
 131} ____cacheline_aligned;
 132
 133/* Helpers to verify state of a clockevent device */
 134static inline bool clockevent_state_detached(struct clock_event_device *dev)
 135{
 136        return dev->state_use_accessors == CLOCK_EVT_STATE_DETACHED;
 137}
 138
 139static inline bool clockevent_state_shutdown(struct clock_event_device *dev)
 140{
 141        return dev->state_use_accessors == CLOCK_EVT_STATE_SHUTDOWN;
 142}
 143
 144static inline bool clockevent_state_periodic(struct clock_event_device *dev)
 145{
 146        return dev->state_use_accessors == CLOCK_EVT_STATE_PERIODIC;
 147}
 148
 149static inline bool clockevent_state_oneshot(struct clock_event_device *dev)
 150{
 151        return dev->state_use_accessors == CLOCK_EVT_STATE_ONESHOT;
 152}
 153
 154static inline bool clockevent_state_oneshot_stopped(struct clock_event_device *dev)
 155{
 156        return dev->state_use_accessors == CLOCK_EVT_STATE_ONESHOT_STOPPED;
 157}
 158
 159/*
 160 * Calculate a multiplication factor for scaled math, which is used to convert
 161 * nanoseconds based values to clock ticks:
 162 *
 163 * clock_ticks = (nanoseconds * factor) >> shift.
 164 *
 165 * div_sc is the rearranged equation to calculate a factor from a given clock
 166 * ticks / nanoseconds ratio:
 167 *
 168 * factor = (clock_ticks << shift) / nanoseconds
 169 */
 170static inline unsigned long
 171div_sc(unsigned long ticks, unsigned long nsec, int shift)
 172{
 173        u64 tmp = ((u64)ticks) << shift;
 174
 175        do_div(tmp, nsec);
 176
 177        return (unsigned long) tmp;
 178}
 179
 180/* Clock event layer functions */
 181extern u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt);
 182extern void clockevents_register_device(struct clock_event_device *dev);
 183extern int clockevents_unbind_device(struct clock_event_device *ced, int cpu);
 184
 185extern void clockevents_config(struct clock_event_device *dev, u32 freq);
 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