tjh.dev
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)
75{
76 asm volatile("stcke %0" : "=Q" (*clk) : : "cc");
77}
78
79static inline unsigned long long get_tod_clock(void)
80{
81 unsigned char clk[16];
82 get_tod_clock_ext(clk);
83 return *((unsigned long long *)&clk[1]);
84}
85
86static inline unsigned long long get_tod_clock_fast(void)
87{
88#ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES
89 unsigned long long clk;
90
91 asm volatile("stckf %0" : "=Q" (clk) : : "cc");
92 return clk;
93#else
94 return get_tod_clock();
95#endif
96}
97
98static inline cycles_t get_cycles(void)
99{
100 return (cycles_t) get_tod_clock() >> 2;
101}
102
103int get_sync_clock(unsigned long long *clock);
104void init_cpu_timer(void);
105unsigned long long monotonic_clock(void);
106
107void tod_to_timeval(__u64, struct timespec *);
108
109static inline
110void stck_to_timespec(unsigned long long stck, struct timespec *ts)
111{
112 tod_to_timeval(stck - TOD_UNIX_EPOCH, ts);
113}
114
115extern u64 sched_clock_base_cc;
116
117/**
118 * get_clock_monotonic - returns current time in clock rate units
119 *
120 * The caller must ensure that preemption is disabled.
121 * The clock and sched_clock_base get changed via stop_machine.
122 * Therefore preemption must be disabled when calling this
123 * function, otherwise the returned value is not guaranteed to
124 * be monotonic.
125 */
126static inline unsigned long long get_tod_clock_monotonic(void)
127{
128 return get_tod_clock() - sched_clock_base_cc;
129}
130
131/**
132 * tod_to_ns - convert a TOD format value to nanoseconds
133 * @todval: to be converted TOD format value
134 * Returns: number of nanoseconds that correspond to the TOD format value
135 *
136 * Converting a 64 Bit TOD format value to nanoseconds means that the value
137 * must be divided by 4.096. In order to achieve that we multiply with 125
138 * and divide by 512:
139 *
140 * ns = (todval * 125) >> 9;
141 *
142 * In order to avoid an overflow with the multiplication we can rewrite this.
143 * With a split todval == 2^32 * th + tl (th upper 32 bits, tl lower 32 bits)
144 * we end up with
145 *
146 * ns = ((2^32 * th + tl) * 125 ) >> 9;
147 * -> ns = (2^23 * th * 125) + ((tl * 125) >> 9);
148 *
149 */
150static inline unsigned long long tod_to_ns(unsigned long long todval)
151{
152 unsigned long long ns;
153
154 ns = ((todval >> 32) << 23) * 125;
155 ns += ((todval & 0xffffffff) * 125) >> 9;
156 return ns;
157}
158
159#endif