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_BUILD
  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
  20 /* Clock event mode commands */
  21 enum clock_event_mode {
  22         CLOCK_EVT_MODE_UNUSED = 0,
  23         CLOCK_EVT_MODE_SHUTDOWN,
  24         CLOCK_EVT_MODE_PERIODIC,
  25         CLOCK_EVT_MODE_ONESHOT,
  26         CLOCK_EVT_MODE_RESUME,
  27 };
  28
  29 /* Clock event notification values */
  30 enum clock_event_nofitiers {
  31         CLOCK_EVT_NOTIFY_ADD,
  32         CLOCK_EVT_NOTIFY_BROADCAST_ON,
  33         CLOCK_EVT_NOTIFY_BROADCAST_OFF,
  34         CLOCK_EVT_NOTIFY_BROADCAST_FORCE,
  35         CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
  36         CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
  37         CLOCK_EVT_NOTIFY_SUSPEND,
  38         CLOCK_EVT_NOTIFY_RESUME,
  39         CLOCK_EVT_NOTIFY_CPU_DYING,
  40         CLOCK_EVT_NOTIFY_CPU_DEAD,
  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  * x86(64) specific misfeatures:
  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  * struct clock_event_device - clock event device descriptor
  60  * @event_handler:      Assigned by the framework to be called by the low
  61  *                      level handler of the event source
  62  * @set_next_event:     set next event function using a clocksource delta
  63  * @set_next_ktime:     set next event function using a direct ktime value
  64  * @next_event:         local storage for the next event in oneshot mode
  65  * @max_delta_ns:       maximum delta value in ns
  66  * @min_delta_ns:       minimum delta value in ns
  67  * @mult:               nanosecond to cycles multiplier
  68  * @shift:              nanoseconds to cycles divisor (power of two)
  69  * @mode:               operating mode assigned by the management code
  70  * @features:           features
  71  * @retries:            number of forced programming retries
  72  * @set_mode:           set mode function
  73  * @broadcast:          function to broadcast events
  74  * @min_delta_ticks:    minimum delta value in ticks stored for reconfiguration
  75  * @max_delta_ticks:    maximum delta value in ticks stored for reconfiguration
  76  * @name:               ptr to clock event name
  77  * @rating:             variable to rate clock event devices
  78  * @irq:                IRQ number (only for non CPU local devices)
  79  * @cpumask:            cpumask to indicate for which CPUs this device works
  80  * @list:               list head for the management code
  81  */
  82 struct clock_event_device {
  83         void                    (*event_handler)(struct clock_event_device *);
  84         int                     (*set_next_event)(unsigned long evt,
  85                                                   struct clock_event_device *);
  86         int                     (*set_next_ktime)(ktime_t expires,
  87                                                   struct clock_event_device *);
  88         ktime_t                 next_event;
  89         u64                     max_delta_ns;
  90         u64                     min_delta_ns;
  91         u32                     mult;
  92         u32                     shift;
  93         enum clock_event_mode   mode;
  94         unsigned int            features;
  95         unsigned long           retries;
  96
  97         void                    (*broadcast)(const struct cpumask *mask);
  98         void                    (*set_mode)(enum clock_event_mode mode,
  99                                             struct clock_event_device *);
 100         unsigned long           min_delta_ticks;
 101         unsigned long           max_delta_ticks;
 102
 103         const char              *name;
 104         int                     rating;
 105         int                     irq;
 106         const struct cpumask    *cpumask;
 107         struct list_head        list;
 108 } ____cacheline_aligned;
 109
 110 /*
 111  * Calculate a multiplication factor for scaled math, which is used to convert
 112  * nanoseconds based values to clock ticks:
 113  *
 114  * clock_ticks = (nanoseconds * factor) >> shift.
 115  *
 116  * div_sc is the rearranged equation to calculate a factor from a given clock
 117  * ticks / nanoseconds ratio:
 118  *
 119  * factor = (clock_ticks << shift) / nanoseconds
 120  */
 121 static inline unsigned long div_sc(unsigned long ticks, unsigned long nsec,
 122                                    int shift)
 123 {
 124         uint64_t tmp = ((uint64_t)ticks) << shift;
 125
 126         do_div(tmp, nsec);
 127         return (unsigned long) tmp;
 128 }
 129
 130 /* Clock event layer functions */
 131 extern u64 clockevent_delta2ns(unsigned long latch,
 132                                struct clock_event_device *evt);
 133 extern void clockevents_register_device(struct clock_event_device *dev);
 134
 135 extern void clockevents_config_and_register(struct clock_event_device *dev,
 136                                             u32 freq, unsigned long min_delta,
 137                                             unsigned long max_delta);
 138
 139 extern int clockevents_update_freq(struct clock_event_device *ce, u32 freq);
 140
 141 extern void clockevents_exchange_device(struct clock_event_device *old,
 142                                         struct clock_event_device *new);
 143 extern void clockevents_set_mode(struct clock_event_device *dev,
 144                                  enum clock_event_mode mode);
 145 extern int clockevents_register_notifier(struct notifier_block *nb);
 146 extern int clockevents_program_event(struct clock_event_device *dev,
 147                                      ktime_t expires, bool force);
 148
 149 extern void clockevents_handle_noop(struct clock_event_device *dev);
 150
 151 static inline void
 152 clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 minsec)
 153 {
 154         return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC,
 155                                       freq, minsec);
 156 }
 157
 158 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 159 extern void clockevents_notify(unsigned long reason, void *arg);
 160 #else
 161 # define clockevents_notify(reason, arg) do { } while (0)
 162 #endif
 163
 164 #else /* CONFIG_GENERIC_CLOCKEVENTS_BUILD */
 165
 166 #define clockevents_notify(reason, arg) do { } while (0)
 167
 168 #endif
 169
 170 #endif