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 #include <linux/time64.h>
  14
  15 /* The value of the TOD clock for 1.1.1970. */
  16 #define TOD_UNIX_EPOCH 0x7d91048bca000000ULL
  17
  18 /* Inline functions for clock register access. */
  19 static inline int set_tod_clock(__u64 time)
  20 {
  21         int cc;
  22
  23         asm volatile(
  24                 "   sck   %1\n"
  25                 "   ipm   %0\n"
  26                 "   srl   %0,28\n"
  27                 : "=d" (cc) : "Q" (time) : "cc");
  28         return cc;
  29 }
  30
  31 static inline int store_tod_clock(__u64 *time)
  32 {
  33         int cc;
  34
  35         asm volatile(
  36                 "   stck  %1\n"
  37                 "   ipm   %0\n"
  38                 "   srl   %0,28\n"
  39                 : "=d" (cc), "=Q" (*time) : : "cc");
  40         return cc;
  41 }
  42
  43 static inline void set_clock_comparator(__u64 time)
  44 {
  45         asm volatile("sckc %0" : : "Q" (time));
  46 }
  47
  48 static inline void store_clock_comparator(__u64 *time)
  49 {
  50         asm volatile("stckc %0" : "=Q" (*time));
  51 }
  52
  53 void clock_comparator_work(void);
  54
  55 static inline unsigned long long local_tick_disable(void)
  56 {
  57         unsigned long long old;
  58
  59         old = S390_lowcore.clock_comparator;
  60         S390_lowcore.clock_comparator = -1ULL;
  61         set_clock_comparator(S390_lowcore.clock_comparator);
  62         return old;
  63 }
  64
  65 static inline void local_tick_enable(unsigned long long comp)
  66 {
  67         S390_lowcore.clock_comparator = comp;
  68         set_clock_comparator(S390_lowcore.clock_comparator);
  69 }
  70
  71 #define CLOCK_TICK_RATE         1193180 /* Underlying HZ */
  72 #define STORE_CLOCK_EXT_SIZE    16      /* stcke writes 16 bytes */
  73
  74 typedef unsigned long long cycles_t;
  75
  76 static inline void get_tod_clock_ext(char *clk)
  77 {
  78         typedef struct { char _[STORE_CLOCK_EXT_SIZE]; } addrtype;
  79
  80         asm volatile("stcke %0" : "=Q" (*(addrtype *) clk) : : "cc");
  81 }
  82
  83 static inline unsigned long long get_tod_clock(void)
  84 {
  85         unsigned char clk[STORE_CLOCK_EXT_SIZE];
  86
  87         get_tod_clock_ext(clk);
  88         return *((unsigned long long *)&clk[1]);
  89 }
  90
  91 static inline unsigned long long get_tod_clock_fast(void)
  92 {
  93 #ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES
  94         unsigned long long clk;
  95
  96         asm volatile("stckf %0" : "=Q" (clk) : : "cc");
  97         return clk;
  98 #else
  99         return get_tod_clock();
 100 #endif
 101 }
 102
 103 static inline cycles_t get_cycles(void)
 104 {
 105         return (cycles_t) get_tod_clock() >> 2;
 106 }
 107
 108 int get_sync_clock(unsigned long long *clock);
 109 void init_cpu_timer(void);
 110 unsigned long long monotonic_clock(void);
 111
 112 void tod_to_timeval(__u64 todval, struct timespec64 *xt);
 113
 114 static inline
 115 void stck_to_timespec64(unsigned long long stck, struct timespec64 *ts)
 116 {
 117         tod_to_timeval(stck - TOD_UNIX_EPOCH, ts);
 118 }
 119
 120 extern u64 sched_clock_base_cc;
 121
 122 /**
 123  * get_clock_monotonic - returns current time in clock rate units
 124  *
 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
 129  * be monotonic.
 130  */
 131 static inline unsigned long long get_tod_clock_monotonic(void)
 132 {
 133         return get_tod_clock() - sched_clock_base_cc;
 134 }
 135
 136 /**
 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
 140  *
 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
 143  * and divide by 512:
 144  *
 145  *    ns = (todval * 125) >> 9;
 146  *
 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)
 149  * we end up with
 150  *
 151  *    ns = ((2^32 * th + tl) * 125 ) >> 9;
 152  * -> ns = (2^23 * th * 125) + ((tl * 125) >> 9);
 153  *
 154  */
 155 static inline unsigned long long tod_to_ns(unsigned long long todval)
 156 {
 157         unsigned long long ns;
 158
 159         ns = ((todval >> 32) << 23) * 125;
 160         ns += ((todval & 0xffffffff) * 125) >> 9;
 161         return ns;
 162 }
 163
 164 #endif