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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1/*
2 * S390 version
3 * Copyright IBM Corp. 1999
4 *
5 * Derived from "include/asm-i386/timex.h"
6 * Copyright (C) 1992, Linus Torvalds
7 */
8
9#ifndef _ASM_S390_TIMEX_H
10#define _ASM_S390_TIMEX_H
11
12#include <asm/lowcore.h>
13
14/* The value of the TOD clock for 1.1.1970. */
15#define TOD_UNIX_EPOCH 0x7d91048bca000000ULL
16
17/* Inline functions for clock register access. */
18static inline int set_tod_clock(__u64 time)
19{
20 int cc;
21
22 asm volatile(
23 " sck %1\n"
24 " ipm %0\n"
25 " srl %0,28\n"
26 : "=d" (cc) : "Q" (time) : "cc");
27 return cc;
28}
29
30static inline int store_tod_clock(__u64 *time)
31{
32 int cc;
33
34 asm volatile(
35 " stck %1\n"
36 " ipm %0\n"
37 " srl %0,28\n"
38 : "=d" (cc), "=Q" (*time) : : "cc");
39 return cc;
40}
41
42static inline void set_clock_comparator(__u64 time)
43{
44 asm volatile("sckc %0" : : "Q" (time));
45}
46
47static inline void store_clock_comparator(__u64 *time)
48{
49 asm volatile("stckc %0" : "=Q" (*time));
50}
51
52void clock_comparator_work(void);
53
54static inline unsigned long long local_tick_disable(void)
55{
56 unsigned long long old;
57
58 old = S390_lowcore.clock_comparator;
59 S390_lowcore.clock_comparator = -1ULL;
60 set_clock_comparator(S390_lowcore.clock_comparator);
61 return old;
62}
63
64static inline void local_tick_enable(unsigned long long comp)
65{
66 S390_lowcore.clock_comparator = comp;
67 set_clock_comparator(S390_lowcore.clock_comparator);
68}
69
70#define CLOCK_TICK_RATE 1193180 /* Underlying HZ */
71
72typedef unsigned long long cycles_t;
73
74static inline void get_tod_clock_ext(char clk[16])
75{
76 typedef struct { char _[sizeof(clk)]; } addrtype;
77
78 asm volatile("stcke %0" : "=Q" (*(addrtype *) clk) : : "cc");
79}
80
81static inline unsigned long long get_tod_clock(void)
82{
83 unsigned char clk[16];
84 get_tod_clock_ext(clk);
85 return *((unsigned long long *)&clk[1]);
86}
87
88static inline unsigned long long get_tod_clock_fast(void)
89{
90#ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES
91 unsigned long long clk;
92
93 asm volatile("stckf %0" : "=Q" (clk) : : "cc");
94 return clk;
95#else
96 return get_tod_clock();
97#endif
98}
99
100static inline cycles_t get_cycles(void)
101{
102 return (cycles_t) get_tod_clock() >> 2;
103}
104
105int get_sync_clock(unsigned long long *clock);
106void init_cpu_timer(void);
107unsigned long long monotonic_clock(void);
108
109void tod_to_timeval(__u64, struct timespec *);
110
111static inline
112void stck_to_timespec(unsigned long long stck, struct timespec *ts)
113{
114 tod_to_timeval(stck - TOD_UNIX_EPOCH, ts);
115}
116
117extern u64 sched_clock_base_cc;
118
119/**
120 * get_clock_monotonic - returns current time in clock rate units
121 *
122 * The caller must ensure that preemption is disabled.
123 * The clock and sched_clock_base get changed via stop_machine.
124 * Therefore preemption must be disabled when calling this
125 * function, otherwise the returned value is not guaranteed to
126 * be monotonic.
127 */
128static inline unsigned long long get_tod_clock_monotonic(void)
129{
130 return get_tod_clock() - sched_clock_base_cc;
131}
132
133/**
134 * tod_to_ns - convert a TOD format value to nanoseconds
135 * @todval: to be converted TOD format value
136 * Returns: number of nanoseconds that correspond to the TOD format value
137 *
138 * Converting a 64 Bit TOD format value to nanoseconds means that the value
139 * must be divided by 4.096. In order to achieve that we multiply with 125
140 * and divide by 512:
141 *
142 * ns = (todval * 125) >> 9;
143 *
144 * In order to avoid an overflow with the multiplication we can rewrite this.
145 * With a split todval == 2^32 * th + tl (th upper 32 bits, tl lower 32 bits)
146 * we end up with
147 *
148 * ns = ((2^32 * th + tl) * 125 ) >> 9;
149 * -> ns = (2^23 * th * 125) + ((tl * 125) >> 9);
150 *
151 */
152static inline unsigned long long tod_to_ns(unsigned long long todval)
153{
154 unsigned long long ns;
155
156 ns = ((todval >> 32) << 23) * 125;
157 ns += ((todval & 0xffffffff) * 125) >> 9;
158 return ns;
159}
160
161#endif