3 * Copyright IBM Corp. 1999
5 * Derived from "include/asm-i386/timex.h"
6 * Copyright (C) 1992, Linus Torvalds
9 #ifndef _ASM_S390_TIMEX_H
10 #define _ASM_S390_TIMEX_H
12 #include <asm/lowcore.h>
13 #include <linux/time64.h>
15 /* The value of the TOD clock for 1.1.1970. */
16 #define TOD_UNIX_EPOCH 0x7d91048bca000000ULL
18 /* Inline functions for clock register access. */
19 static inline int set_tod_clock(__u64 time)
27 : "=d" (cc) : "Q" (time) : "cc");
31 static inline int store_tod_clock(__u64 *time)
39 : "=d" (cc), "=Q" (*time) : : "cc");
43 static inline void set_clock_comparator(__u64 time)
45 asm volatile("sckc %0" : : "Q" (time));
48 static inline void store_clock_comparator(__u64 *time)
50 asm volatile("stckc %0" : "=Q" (*time));
53 void clock_comparator_work(void);
55 static inline unsigned long long local_tick_disable(void)
57 unsigned long long old;
59 old = S390_lowcore.clock_comparator;
60 S390_lowcore.clock_comparator = -1ULL;
61 set_clock_comparator(S390_lowcore.clock_comparator);
65 static inline void local_tick_enable(unsigned long long comp)
67 S390_lowcore.clock_comparator = comp;
68 set_clock_comparator(S390_lowcore.clock_comparator);
71 #define CLOCK_TICK_RATE 1193180 /* Underlying HZ */
72 #define STORE_CLOCK_EXT_SIZE 16 /* stcke writes 16 bytes */
74 typedef unsigned long long cycles_t;
76 static inline void get_tod_clock_ext(char *clk)
78 typedef struct { char _[STORE_CLOCK_EXT_SIZE]; } addrtype;
80 asm volatile("stcke %0" : "=Q" (*(addrtype *) clk) : : "cc");
83 static inline unsigned long long get_tod_clock(void)
85 unsigned char clk[STORE_CLOCK_EXT_SIZE];
87 get_tod_clock_ext(clk);
88 return *((unsigned long long *)&clk[1]);
91 static inline unsigned long long get_tod_clock_fast(void)
93 #ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES
94 unsigned long long clk;
96 asm volatile("stckf %0" : "=Q" (clk) : : "cc");
99 return get_tod_clock();
103 static inline cycles_t get_cycles(void)
105 return (cycles_t) get_tod_clock() >> 2;
108 int get_sync_clock(unsigned long long *clock);
109 void init_cpu_timer(void);
110 unsigned long long monotonic_clock(void);
112 void tod_to_timeval(__u64 todval, struct timespec64 *xt);
115 void stck_to_timespec64(unsigned long long stck, struct timespec64 *ts)
117 tod_to_timeval(stck - TOD_UNIX_EPOCH, ts);
120 extern u64 sched_clock_base_cc;
123 * get_clock_monotonic - returns current time in clock rate units
125 * The caller must ensure that preemption is disabled.
126 * The clock and sched_clock_base get changed via stop_machine.
127 * Therefore preemption must be disabled when calling this
128 * function, otherwise the returned value is not guaranteed to
131 static inline unsigned long long get_tod_clock_monotonic(void)
133 return get_tod_clock() - sched_clock_base_cc;
137 * tod_to_ns - convert a TOD format value to nanoseconds
138 * @todval: to be converted TOD format value
139 * Returns: number of nanoseconds that correspond to the TOD format value
141 * Converting a 64 Bit TOD format value to nanoseconds means that the value
142 * must be divided by 4.096. In order to achieve that we multiply with 125
145 * ns = (todval * 125) >> 9;
147 * In order to avoid an overflow with the multiplication we can rewrite this.
148 * With a split todval == 2^32 * th + tl (th upper 32 bits, tl lower 32 bits)
151 * ns = ((2^32 * th + tl) * 125 ) >> 9;
152 * -> ns = (2^23 * th * 125) + ((tl * 125) >> 9);
155 static inline unsigned long long tod_to_ns(unsigned long long todval)
157 unsigned long long ns;
159 ns = ((todval >> 32) << 23) * 125;
160 ns += ((todval & 0xffffffff) * 125) >> 9;