root/include/linux/clockchips.h

INCLUDED FROM

DEFINITIONS

1. clockevent_state_detached
2. clockevent_state_shutdown
3. clockevent_state_periodic
4. clockevent_state_oneshot
5. clockevent_state_oneshot_stopped
6. div_sc
7. clockevents_calc_mult_shift
8. tick_check_broadcast_expired
9. tick_setup_hrtimer_broadcast
10. clockevents_suspend
11. clockevents_resume
12. tick_check_broadcast_expired
13. tick_setup_hrtimer_broadcast

   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 
  19 struct clock_event_device;
  20 struct 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  */
  35 enum 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  */
 100 struct 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 */
 135 static inline bool clockevent_state_detached(struct clock_event_device *dev)
 136 {
 137         return dev->state_use_accessors == CLOCK_EVT_STATE_DETACHED;
 138 }
 139 
 140 static inline bool clockevent_state_shutdown(struct clock_event_device *dev)
 141 {
 142         return dev->state_use_accessors == CLOCK_EVT_STATE_SHUTDOWN;
 143 }
 144 
 145 static inline bool clockevent_state_periodic(struct clock_event_device *dev)
 146 {
 147         return dev->state_use_accessors == CLOCK_EVT_STATE_PERIODIC;
 148 }
 149 
 150 static inline bool clockevent_state_oneshot(struct clock_event_device *dev)
 151 {
 152         return dev->state_use_accessors == CLOCK_EVT_STATE_ONESHOT;
 153 }
 154 
 155 static 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  */
 171 static inline unsigned long
 172 div_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 */
 182 extern u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt);
 183 extern void clockevents_register_device(struct clock_event_device *dev);
 184 extern int clockevents_unbind_device(struct clock_event_device *ced, int cpu);
 185 
 186 extern void clockevents_config_and_register(struct clock_event_device *dev,
 187                                             u32 freq, unsigned long min_delta,
 188                                             unsigned long max_delta);
 189 
 190 extern int clockevents_update_freq(struct clock_event_device *ce, u32 freq);
 191 
 192 static inline void
 193 clockevents_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 
 198 extern void clockevents_suspend(void);
 199 extern void clockevents_resume(void);
 200 
 201 # ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 202 #  ifdef CONFIG_ARCH_HAS_TICK_BROADCAST
 203 extern void tick_broadcast(const struct cpumask *mask);
 204 #  else
 205 #   define tick_broadcast       NULL
 206 #  endif
 207 extern int tick_receive_broadcast(void);
 208 # endif
 209 
 210 # if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
 211 extern void tick_setup_hrtimer_broadcast(void);
 212 extern int tick_check_broadcast_expired(void);
 213 # else
 214 static inline int tick_check_broadcast_expired(void) { return 0; }
 215 static inline void tick_setup_hrtimer_broadcast(void) { }
 216 # endif
 217 
 218 #else /* !CONFIG_GENERIC_CLOCKEVENTS: */
 219 
 220 static inline void clockevents_suspend(void) { }
 221 static inline void clockevents_resume(void) { }
 222 static inline int tick_check_broadcast_expired(void) { return 0; }
 223 static inline void tick_setup_hrtimer_broadcast(void) { }
 224 
 225 #endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 226 
 227 #endif /* _LINUX_CLOCKCHIPS_H */