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