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 /* Clock event mode commands for legacy ->set_mode(): OBSOLETE */
  22 enum clock_event_mode {
  23         CLOCK_EVT_MODE_UNUSED,
  24         CLOCK_EVT_MODE_SHUTDOWN,
  25         CLOCK_EVT_MODE_PERIODIC,
  26         CLOCK_EVT_MODE_ONESHOT,
  27         CLOCK_EVT_MODE_RESUME,
  28 };
  29
  30 /*
  31  * Possible states of a clock event device.
  32  *
  33  * DETACHED:    Device is not used by clockevents core. Initial state or can be
  34  *              reached from SHUTDOWN.
  35  * SHUTDOWN:    Device is powered-off. Can be reached from PERIODIC or ONESHOT.
  36  * PERIODIC:    Device is programmed to generate events periodically. Can be
  37  *              reached from DETACHED or SHUTDOWN.
  38  * ONESHOT:     Device is programmed to generate event only once. Can be reached
  39  *              from DETACHED or SHUTDOWN.
  40  * ONESHOT_STOPPED: Device was programmed in ONESHOT mode and is temporarily
  41  *                  stopped.
  42  */
  43 enum clock_event_state {
  44         CLOCK_EVT_STATE_DETACHED,
  45         CLOCK_EVT_STATE_SHUTDOWN,
  46         CLOCK_EVT_STATE_PERIODIC,
  47         CLOCK_EVT_STATE_ONESHOT,
  48         CLOCK_EVT_STATE_ONESHOT_STOPPED,
  49 };
  50
  51 /*
  52  * Clock event features
  53  */
  54 # define CLOCK_EVT_FEAT_PERIODIC        0x000001
  55 # define CLOCK_EVT_FEAT_ONESHOT         0x000002
  56 # define CLOCK_EVT_FEAT_KTIME           0x000004
  57
  58 /*
  59  * x86(64) specific (mis)features:
  60  *
  61  * - Clockevent source stops in C3 State and needs broadcast support.
  62  * - Local APIC timer is used as a dummy device.
  63  */
  64 # define CLOCK_EVT_FEAT_C3STOP          0x000008
  65 # define CLOCK_EVT_FEAT_DUMMY           0x000010
  66
  67 /*
  68  * Core shall set the interrupt affinity dynamically in broadcast mode
  69  */
  70 # define CLOCK_EVT_FEAT_DYNIRQ          0x000020
  71 # define CLOCK_EVT_FEAT_PERCPU          0x000040
  72
  73 /*
  74  * Clockevent device is based on a hrtimer for broadcast
  75  */
  76 # define CLOCK_EVT_FEAT_HRTIMER         0x000080
  77
  78 /**
  79  * struct clock_event_device - clock event device descriptor
  80  * @event_handler:      Assigned by the framework to be called by the low
  81  *                      level handler of the event source
  82  * @set_next_event:     set next event function using a clocksource delta
  83  * @set_next_ktime:     set next event function using a direct ktime value
  84  * @next_event:         local storage for the next event in oneshot mode
  85  * @max_delta_ns:       maximum delta value in ns
  86  * @min_delta_ns:       minimum delta value in ns
  87  * @mult:               nanosecond to cycles multiplier
  88  * @shift:              nanoseconds to cycles divisor (power of two)
  89  * @mode:               operating mode, relevant only to ->set_mode(), OBSOLETE
  90  * @state_use_accessors:current state of the device, assigned by the core code
  91  * @features:           features
  92  * @retries:            number of forced programming retries
  93  * @set_mode:           legacy set mode function, only for modes <= CLOCK_EVT_MODE_RESUME.
  94  * @set_state_periodic: switch state to periodic, if !set_mode
  95  * @set_state_oneshot:  switch state to oneshot, if !set_mode
  96  * @set_state_oneshot_stopped: switch state to oneshot_stopped, if !set_mode
  97  * @set_state_shutdown: switch state to shutdown, if !set_mode
  98  * @tick_resume:        resume clkevt device, if !set_mode
  99  * @broadcast:          function to broadcast events
 100  * @min_delta_ticks:    minimum delta value in ticks stored for reconfiguration
 101  * @max_delta_ticks:    maximum delta value in ticks stored for reconfiguration
 102  * @name:               ptr to clock event name
 103  * @rating:             variable to rate clock event devices
 104  * @irq:                IRQ number (only for non CPU local devices)
 105  * @bound_on:           Bound on CPU
 106  * @cpumask:            cpumask to indicate for which CPUs this device works
 107  * @list:               list head for the management code
 108  * @owner:              module reference
 109  */
 110 struct clock_event_device {
 111         void                    (*event_handler)(struct clock_event_device *);
 112         int                     (*set_next_event)(unsigned long evt, struct clock_event_device *);
 113         int                     (*set_next_ktime)(ktime_t expires, struct clock_event_device *);
 114         ktime_t                 next_event;
 115         u64                     max_delta_ns;
 116         u64                     min_delta_ns;
 117         u32                     mult;
 118         u32                     shift;
 119         enum clock_event_mode   mode;
 120         enum clock_event_state  state_use_accessors;
 121         unsigned int            features;
 122         unsigned long           retries;
 123
 124         /*
 125          * State transition callback(s): Only one of the two groups should be
 126          * defined:
 127          * - set_mode(), only for modes <= CLOCK_EVT_MODE_RESUME.
 128          * - set_state_{shutdown|periodic|oneshot|oneshot_stopped}(), tick_resume().
 129          */
 130         void                    (*set_mode)(enum clock_event_mode mode, struct clock_event_device *);
 131         int                     (*set_state_periodic)(struct clock_event_device *);
 132         int                     (*set_state_oneshot)(struct clock_event_device *);
 133         int                     (*set_state_oneshot_stopped)(struct clock_event_device *);
 134         int                     (*set_state_shutdown)(struct clock_event_device *);
 135         int                     (*tick_resume)(struct clock_event_device *);
 136
 137         void                    (*broadcast)(const struct cpumask *mask);
 138         void                    (*suspend)(struct clock_event_device *);
 139         void                    (*resume)(struct clock_event_device *);
 140         unsigned long           min_delta_ticks;
 141         unsigned long           max_delta_ticks;
 142
 143         const char              *name;
 144         int                     rating;
 145         int                     irq;
 146         int                     bound_on;
 147         const struct cpumask    *cpumask;
 148         struct list_head        list;
 149         struct module           *owner;
 150 } ____cacheline_aligned;
 151
 152 /* Helpers to verify state of a clockevent device */
 153 static inline bool clockevent_state_detached(struct clock_event_device *dev)
 154 {
 155         return dev->state_use_accessors == CLOCK_EVT_STATE_DETACHED;
 156 }
 157
 158 static inline bool clockevent_state_shutdown(struct clock_event_device *dev)
 159 {
 160         return dev->state_use_accessors == CLOCK_EVT_STATE_SHUTDOWN;
 161 }
 162
 163 static inline bool clockevent_state_periodic(struct clock_event_device *dev)
 164 {
 165         return dev->state_use_accessors == CLOCK_EVT_STATE_PERIODIC;
 166 }
 167
 168 static inline bool clockevent_state_oneshot(struct clock_event_device *dev)
 169 {
 170         return dev->state_use_accessors == CLOCK_EVT_STATE_ONESHOT;
 171 }
 172
 173 static inline bool clockevent_state_oneshot_stopped(struct clock_event_device *dev)
 174 {
 175         return dev->state_use_accessors == CLOCK_EVT_STATE_ONESHOT_STOPPED;
 176 }
 177
 178 /*
 179  * Calculate a multiplication factor for scaled math, which is used to convert
 180  * nanoseconds based values to clock ticks:
 181  *
 182  * clock_ticks = (nanoseconds * factor) >> shift.
 183  *
 184  * div_sc is the rearranged equation to calculate a factor from a given clock
 185  * ticks / nanoseconds ratio:
 186  *
 187  * factor = (clock_ticks << shift) / nanoseconds
 188  */
 189 static inline unsigned long
 190 div_sc(unsigned long ticks, unsigned long nsec, int shift)
 191 {
 192         u64 tmp = ((u64)ticks) << shift;
 193
 194         do_div(tmp, nsec);
 195
 196         return (unsigned long) tmp;
 197 }
 198
 199 /* Clock event layer functions */
 200 extern u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt);
 201 extern void clockevents_register_device(struct clock_event_device *dev);
 202 extern int clockevents_unbind_device(struct clock_event_device *ced, int cpu);
 203
 204 extern void clockevents_config(struct clock_event_device *dev, u32 freq);
 205 extern void clockevents_config_and_register(struct clock_event_device *dev,
 206                                             u32 freq, unsigned long min_delta,
 207                                             unsigned long max_delta);
 208
 209 extern int clockevents_update_freq(struct clock_event_device *ce, u32 freq);
 210
 211 static inline void
 212 clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 minsec)
 213 {
 214         return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC, freq, minsec);
 215 }
 216
 217 extern void clockevents_suspend(void);
 218 extern void clockevents_resume(void);
 219
 220 # ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 221 #  ifdef CONFIG_ARCH_HAS_TICK_BROADCAST
 222 extern void tick_broadcast(const struct cpumask *mask);
 223 #  else
 224 #   define tick_broadcast       NULL
 225 #  endif
 226 extern int tick_receive_broadcast(void);
 227 # endif
 228
 229 # if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
 230 extern void tick_setup_hrtimer_broadcast(void);
 231 extern int tick_check_broadcast_expired(void);
 232 # else
 233 static inline int tick_check_broadcast_expired(void) { return 0; }
 234 static inline void tick_setup_hrtimer_broadcast(void) { }
 235 # endif
 236
 237 extern int clockevents_notify(unsigned long reason, void *arg);
 238
 239 #else /* !CONFIG_GENERIC_CLOCKEVENTS: */
 240
 241 static inline void clockevents_suspend(void) { }
 242 static inline void clockevents_resume(void) { }
 243 static inline int clockevents_notify(unsigned long reason, void *arg) { return 0; }
 244 static inline int tick_check_broadcast_expired(void) { return 0; }
 245 static inline void tick_setup_hrtimer_broadcast(void) { }
 246
 247 #endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 248
 249 #endif /* _LINUX_CLOCKCHIPS_H */