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
  18 struct clock_event_device;
  19 struct 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  */
  34 enum 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  */
  99 struct 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 */
 134 static inline bool clockevent_state_detached(struct clock_event_device *dev)
 135 {
 136         return dev->state_use_accessors == CLOCK_EVT_STATE_DETACHED;
 137 }
 138
 139 static inline bool clockevent_state_shutdown(struct clock_event_device *dev)
 140 {
 141         return dev->state_use_accessors == CLOCK_EVT_STATE_SHUTDOWN;
 142 }
 143
 144 static inline bool clockevent_state_periodic(struct clock_event_device *dev)
 145 {
 146         return dev->state_use_accessors == CLOCK_EVT_STATE_PERIODIC;
 147 }
 148
 149 static inline bool clockevent_state_oneshot(struct clock_event_device *dev)
 150 {
 151         return dev->state_use_accessors == CLOCK_EVT_STATE_ONESHOT;
 152 }
 153
 154 static 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  */
 170 static inline unsigned long
 171 div_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 */
 181 extern u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt);
 182 extern void clockevents_register_device(struct clock_event_device *dev);
 183 extern int clockevents_unbind_device(struct clock_event_device *ced, int cpu);
 184
 185 extern void clockevents_config(struct clock_event_device *dev, u32 freq);
 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 */