xref: /openbmc/linux/arch/s390/include/asm/timex.h (revision c4ee0af3)
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. */
18 static 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 
30 static 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 
42 static inline void set_clock_comparator(__u64 time)
43 {
44 	asm volatile("sckc %0" : : "Q" (time));
45 }
46 
47 static inline void store_clock_comparator(__u64 *time)
48 {
49 	asm volatile("stckc %0" : "=Q" (*time));
50 }
51 
52 void clock_comparator_work(void);
53 
54 static 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 
64 static 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 
72 typedef unsigned long long cycles_t;
73 
74 static 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 
81 static 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 
88 static 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 
100 static inline cycles_t get_cycles(void)
101 {
102 	return (cycles_t) get_tod_clock() >> 2;
103 }
104 
105 int get_sync_clock(unsigned long long *clock);
106 void init_cpu_timer(void);
107 unsigned long long monotonic_clock(void);
108 
109 void tod_to_timeval(__u64, struct timespec *);
110 
111 static inline
112 void stck_to_timespec(unsigned long long stck, struct timespec *ts)
113 {
114 	tod_to_timeval(stck - TOD_UNIX_EPOCH, ts);
115 }
116 
117 extern 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  */
128 static 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  */
152 static 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
162