arch/s390/include/asm/timex.h

   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 unsigned long long get_tod_clock(void)
  75 {
  76         unsigned long long clk;
  77
  78 #ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES
  79         asm volatile(".insn s,0xb27c0000,%0" : "=Q" (clk) : : "cc");
  80 #else
  81         asm volatile("stck %0" : "=Q" (clk) : : "cc");
  82 #endif
  83         return clk;
  84 }
  85
  86 static inline void get_tod_clock_ext(char *clk)
  87 {
  88         asm volatile("stcke %0" : "=Q" (*clk) : : "cc");
  89 }
  90
  91 static inline unsigned long long get_tod_clock_xt(void)
  92 {
  93         unsigned char clk[16];
  94         get_tod_clock_ext(clk);
  95         return *((unsigned long long *)&clk[1]);
  96 }
  97
  98 static inline cycles_t get_cycles(void)
  99 {
 100         return (cycles_t) get_tod_clock() >> 2;
 101 }
 102
 103 int get_sync_clock(unsigned long long *clock);
 104 void init_cpu_timer(void);
 105 unsigned long long monotonic_clock(void);
 106
 107 void tod_to_timeval(__u64, struct timespec *);
 108
 109 static inline
 110 void stck_to_timespec(unsigned long long stck, struct timespec *ts)
 111 {
 112         tod_to_timeval(stck - TOD_UNIX_EPOCH, ts);
 113 }
 114
 115 extern 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  */
 126 static inline unsigned long long get_tod_clock_monotonic(void)
 127 {
 128         return get_tod_clock_xt() - 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  */
 150 static 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