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-rw-r--r--include/linux/clocksource.h102
1 files changed, 0 insertions, 102 deletions
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index abcafaa20b86..9c78d15d33e4 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -18,8 +18,6 @@
18#include <asm/div64.h> 18#include <asm/div64.h>
19#include <asm/io.h> 19#include <asm/io.h>
20 20
21/* clocksource cycle base type */
22typedef u64 cycle_t;
23struct clocksource; 21struct clocksource;
24struct module; 22struct module;
25 23
@@ -28,106 +26,6 @@ struct module;
28#endif 26#endif
29 27
30/** 28/**
31 * struct cyclecounter - hardware abstraction for a free running counter
32 * Provides completely state-free accessors to the underlying hardware.
33 * Depending on which hardware it reads, the cycle counter may wrap
34 * around quickly. Locking rules (if necessary) have to be defined
35 * by the implementor and user of specific instances of this API.
36 *
37 * @read: returns the current cycle value
38 * @mask: bitmask for two's complement
39 * subtraction of non 64 bit counters,
40 * see CLOCKSOURCE_MASK() helper macro
41 * @mult: cycle to nanosecond multiplier
42 * @shift: cycle to nanosecond divisor (power of two)
43 */
44struct cyclecounter {
45 cycle_t (*read)(const struct cyclecounter *cc);
46 cycle_t mask;
47 u32 mult;
48 u32 shift;
49};
50
51/**
52 * struct timecounter - layer above a %struct cyclecounter which counts nanoseconds
53 * Contains the state needed by timecounter_read() to detect
54 * cycle counter wrap around. Initialize with
55 * timecounter_init(). Also used to convert cycle counts into the
56 * corresponding nanosecond counts with timecounter_cyc2time(). Users
57 * of this code are responsible for initializing the underlying
58 * cycle counter hardware, locking issues and reading the time
59 * more often than the cycle counter wraps around. The nanosecond
60 * counter will only wrap around after ~585 years.
61 *
62 * @cc: the cycle counter used by this instance
63 * @cycle_last: most recent cycle counter value seen by
64 * timecounter_read()
65 * @nsec: continuously increasing count
66 */
67struct timecounter {
68 const struct cyclecounter *cc;
69 cycle_t cycle_last;
70 u64 nsec;
71};
72
73/**
74 * cyclecounter_cyc2ns - converts cycle counter cycles to nanoseconds
75 * @cc: Pointer to cycle counter.
76 * @cycles: Cycles
77 *
78 * XXX - This could use some mult_lxl_ll() asm optimization. Same code
79 * as in cyc2ns, but with unsigned result.
80 */
81static inline u64 cyclecounter_cyc2ns(const struct cyclecounter *cc,
82 cycle_t cycles)
83{
84 u64 ret = (u64)cycles;
85 ret = (ret * cc->mult) >> cc->shift;
86 return ret;
87}
88
89/**
90 * timecounter_init - initialize a time counter
91 * @tc: Pointer to time counter which is to be initialized/reset
92 * @cc: A cycle counter, ready to be used.
93 * @start_tstamp: Arbitrary initial time stamp.
94 *
95 * After this call the current cycle register (roughly) corresponds to
96 * the initial time stamp. Every call to timecounter_read() increments
97 * the time stamp counter by the number of elapsed nanoseconds.
98 */
99extern void timecounter_init(struct timecounter *tc,
100 const struct cyclecounter *cc,
101 u64 start_tstamp);
102
103/**
104 * timecounter_read - return nanoseconds elapsed since timecounter_init()
105 * plus the initial time stamp
106 * @tc: Pointer to time counter.
107 *
108 * In other words, keeps track of time since the same epoch as
109 * the function which generated the initial time stamp.
110 */
111extern u64 timecounter_read(struct timecounter *tc);
112
113/**
114 * timecounter_cyc2time - convert a cycle counter to same
115 * time base as values returned by
116 * timecounter_read()
117 * @tc: Pointer to time counter.
118 * @cycle_tstamp: a value returned by tc->cc->read()
119 *
120 * Cycle counts that are converted correctly as long as they
121 * fall into the interval [-1/2 max cycle count, +1/2 max cycle count],
122 * with "max cycle count" == cs->mask+1.
123 *
124 * This allows conversion of cycle counter values which were generated
125 * in the past.
126 */
127extern u64 timecounter_cyc2time(struct timecounter *tc,
128 cycle_t cycle_tstamp);
129
130/**
131 * struct clocksource - hardware abstraction for a free running counter 29 * struct clocksource - hardware abstraction for a free running counter
132 * Provides mostly state-free accessors to the underlying hardware. 30 * Provides mostly state-free accessors to the underlying hardware.
133 * This is the structure used for system time. 31 * This is the structure used for system time.