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
  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 };
  27
  28 /* Clock event notification values */
  29 enum clock_event_nofitiers {
  30         CLOCK_EVT_NOTIFY_ADD,
  31         CLOCK_EVT_NOTIFY_BROADCAST_ON,
  32         CLOCK_EVT_NOTIFY_BROADCAST_OFF,
  33         CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
  34         CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
  35         CLOCK_EVT_NOTIFY_SUSPEND,
  36         CLOCK_EVT_NOTIFY_RESUME,
  37         CLOCK_EVT_NOTIFY_CPU_DEAD,
  38 };
  39
  40 /*
  41  * Clock event features
  42  */
  43 #define CLOCK_EVT_FEAT_PERIODIC         0x000001
  44 #define CLOCK_EVT_FEAT_ONESHOT          0x000002
  45 /*
  46  * x86(64) specific misfeatures:
  47  *
  48  * - Clockevent source stops in C3 State and needs broadcast support.
  49  * - Local APIC timer is used as a dummy device.
  50  */
  51 #define CLOCK_EVT_FEAT_C3STOP           0x000004
  52 #define CLOCK_EVT_FEAT_DUMMY            0x000008
  53
  54 /**
  55  * struct clock_event_device - clock event device descriptor
  56  * @name:               ptr to clock event name
  57  * @features:           features
  58  * @max_delta_ns:       maximum delta value in ns
  59  * @min_delta_ns:       minimum delta value in ns
  60  * @mult:               nanosecond to cycles multiplier
  61  * @shift:              nanoseconds to cycles divisor (power of two)
  62  * @rating:             variable to rate clock event devices
  63  * @irq:                IRQ number (only for non CPU local devices)
  64  * @cpumask:            cpumask to indicate for which CPUs this device works
  65  * @set_next_event:     set next event function
  66  * @set_mode:           set mode function
  67  * @event_handler:      Assigned by the framework to be called by the low
  68  *                      level handler of the event source
  69  * @broadcast:          function to broadcast events
  70  * @list:               list head for the management code
  71  * @mode:               operating mode assigned by the management code
  72  * @next_event:         local storage for the next event in oneshot mode
  73  */
  74 struct clock_event_device {
  75         const char              *name;
  76         unsigned int            features;
  77         unsigned long           max_delta_ns;
  78         unsigned long           min_delta_ns;
  79         unsigned long           mult;
  80         int                     shift;
  81         int                     rating;
  82         int                     irq;
  83         cpumask_t               cpumask;
  84         int                     (*set_next_event)(unsigned long evt,
  85                                                   struct clock_event_device *);
  86         void                    (*set_mode)(enum clock_event_mode mode,
  87                                             struct clock_event_device *);
  88         void                    (*event_handler)(struct clock_event_device *);
  89         void                    (*broadcast)(cpumask_t mask);
  90         struct list_head        list;
  91         enum clock_event_mode   mode;
  92         ktime_t                 next_event;
  93 };
  94
  95 /*
  96  * Calculate a multiplication factor for scaled math, which is used to convert
  97  * nanoseconds based values to clock ticks:
  98  *
  99  * clock_ticks = (nanoseconds * factor) >> shift.
 100  *
 101  * div_sc is the rearranged equation to calculate a factor from a given clock
 102  * ticks / nanoseconds ratio:
 103  *
 104  * factor = (clock_ticks << shift) / nanoseconds
 105  */
 106 static inline unsigned long div_sc(unsigned long ticks, unsigned long nsec,
 107                                    int shift)
 108 {
 109         uint64_t tmp = ((uint64_t)ticks) << shift;
 110
 111         do_div(tmp, nsec);
 112         return (unsigned long) tmp;
 113 }
 114
 115 /* Clock event layer functions */
 116 extern unsigned long clockevent_delta2ns(unsigned long latch,
 117                                          struct clock_event_device *evt);
 118 extern void clockevents_register_device(struct clock_event_device *dev);
 119
 120 extern void clockevents_exchange_device(struct clock_event_device *old,
 121                                         struct clock_event_device *new);
 122 extern
 123 struct clock_event_device *clockevents_request_device(unsigned int features,
 124                                                       cpumask_t cpumask);
 125 extern void clockevents_release_device(struct clock_event_device *dev);
 126 extern void clockevents_set_mode(struct clock_event_device *dev,
 127                                  enum clock_event_mode mode);
 128 extern int clockevents_register_notifier(struct notifier_block *nb);
 129 extern void clockevents_unregister_notifier(struct notifier_block *nb);
 130 extern int clockevents_program_event(struct clock_event_device *dev,
 131                                      ktime_t expires, ktime_t now);
 132
 133 extern void clockevents_notify(unsigned long reason, void *arg);
 134
 135 #else
 136
 137 static inline void clockevents_resume_events(void) { }
 138 #define clockevents_notify(reason, arg) do { } while (0)
 139
 140 #endif
 141
 142 #endif