include/linux/ktime.h

   1 /*
   2  *  include/linux/ktime.h
   3  *
   4  *  ktime_t - nanosecond-resolution time format.
   5  *
   6  *   Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
   7  *   Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
   8  *
   9  *  data type definitions, declarations, prototypes and macros.
  10  *
  11  *  Started by: Thomas Gleixner and Ingo Molnar
  12  *
  13  *  Credits:
  14  *
  15  *      Roman Zippel provided the ideas and primary code snippets of
  16  *      the ktime_t union and further simplifications of the original
  17  *      code.
  18  *
  19  *  For licencing details see kernel-base/COPYING
  20  */
  21 #ifndef _LINUX_KTIME_H
  22 #define _LINUX_KTIME_H
  23
  24 #include <linux/time.h>
  25 #include <linux/jiffies.h>
  26
  27 /*
  28  * ktime_t:
  29  *
  30  * A single 64-bit variable is used to store the hrtimers
  31  * internal representation of time values in scalar nanoseconds. The
  32  * design plays out best on 64-bit CPUs, where most conversions are
  33  * NOPs and most arithmetic ktime_t operations are plain arithmetic
  34  * operations.
  35  *
  36  */
  37 union ktime {
  38         s64     tv64;
  39 };
  40
  41 typedef union ktime ktime_t;            /* Kill this */
  42
  43 /**
  44  * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value
  45  * @secs:       seconds to set
  46  * @nsecs:      nanoseconds to set
  47  *
  48  * Return: The ktime_t representation of the value.
  49  */
  50 static inline ktime_t ktime_set(const s64 secs, const unsigned long nsecs)
  51 {
  52         if (unlikely(secs >= KTIME_SEC_MAX))
  53                 return (ktime_t){ .tv64 = KTIME_MAX };
  54
  55         return (ktime_t) { .tv64 = secs * NSEC_PER_SEC + (s64)nsecs };
  56 }
  57
  58 /* Subtract two ktime_t variables. rem = lhs -rhs: */
  59 #define ktime_sub(lhs, rhs) \
  60                 ({ (ktime_t){ .tv64 = (lhs).tv64 - (rhs).tv64 }; })
  61
  62 /* Add two ktime_t variables. res = lhs + rhs: */
  63 #define ktime_add(lhs, rhs) \
  64                 ({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; })
  65
  66 /*
  67  * Add a ktime_t variable and a scalar nanosecond value.
  68  * res = kt + nsval:
  69  */
  70 #define ktime_add_ns(kt, nsval) \
  71                 ({ (ktime_t){ .tv64 = (kt).tv64 + (nsval) }; })
  72
  73 /*
  74  * Subtract a scalar nanosecod from a ktime_t variable
  75  * res = kt - nsval:
  76  */
  77 #define ktime_sub_ns(kt, nsval) \
  78                 ({ (ktime_t){ .tv64 = (kt).tv64 - (nsval) }; })
  79
  80 /* convert a timespec to ktime_t format: */
  81 static inline ktime_t timespec_to_ktime(struct timespec ts)
  82 {
  83         return ktime_set(ts.tv_sec, ts.tv_nsec);
  84 }
  85
  86 /* convert a timeval to ktime_t format: */
  87 static inline ktime_t timeval_to_ktime(struct timeval tv)
  88 {
  89         return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
  90 }
  91
  92 /* Map the ktime_t to timespec conversion to ns_to_timespec function */
  93 #define ktime_to_timespec(kt)           ns_to_timespec((kt).tv64)
  94
  95 /* Map the ktime_t to timeval conversion to ns_to_timeval function */
  96 #define ktime_to_timeval(kt)            ns_to_timeval((kt).tv64)
  97
  98 /* Convert ktime_t to nanoseconds - NOP in the scalar storage format: */
  99 #define ktime_to_ns(kt)                 ((kt).tv64)
 100
 101
 102 /**
 103  * ktime_equal - Compares two ktime_t variables to see if they are equal
 104  * @cmp1:       comparable1
 105  * @cmp2:       comparable2
 106  *
 107  * Compare two ktime_t variables.
 108  *
 109  * Return: 1 if equal.
 110  */
 111 static inline int ktime_equal(const ktime_t cmp1, const ktime_t cmp2)
 112 {
 113         return cmp1.tv64 == cmp2.tv64;
 114 }
 115
 116 /**
 117  * ktime_compare - Compares two ktime_t variables for less, greater or equal
 118  * @cmp1:       comparable1
 119  * @cmp2:       comparable2
 120  *
 121  * Return: ...
 122  *   cmp1  < cmp2: return <0
 123  *   cmp1 == cmp2: return 0
 124  *   cmp1  > cmp2: return >0
 125  */
 126 static inline int ktime_compare(const ktime_t cmp1, const ktime_t cmp2)
 127 {
 128         if (cmp1.tv64 < cmp2.tv64)
 129                 return -1;
 130         if (cmp1.tv64 > cmp2.tv64)
 131                 return 1;
 132         return 0;
 133 }
 134
 135 /**
 136  * ktime_after - Compare if a ktime_t value is bigger than another one.
 137  * @cmp1:       comparable1
 138  * @cmp2:       comparable2
 139  *
 140  * Return: true if cmp1 happened after cmp2.
 141  */
 142 static inline bool ktime_after(const ktime_t cmp1, const ktime_t cmp2)
 143 {
 144         return ktime_compare(cmp1, cmp2) > 0;
 145 }
 146
 147 /**
 148  * ktime_before - Compare if a ktime_t value is smaller than another one.
 149  * @cmp1:       comparable1
 150  * @cmp2:       comparable2
 151  *
 152  * Return: true if cmp1 happened before cmp2.
 153  */
 154 static inline bool ktime_before(const ktime_t cmp1, const ktime_t cmp2)
 155 {
 156         return ktime_compare(cmp1, cmp2) < 0;
 157 }
 158
 159 #if BITS_PER_LONG < 64
 160 extern u64 ktime_divns(const ktime_t kt, s64 div);
 161 #else /* BITS_PER_LONG < 64 */
 162 # define ktime_divns(kt, div)           (u64)((kt).tv64 / (div))
 163 #endif
 164
 165 static inline s64 ktime_to_us(const ktime_t kt)
 166 {
 167         return ktime_divns(kt, NSEC_PER_USEC);
 168 }
 169
 170 static inline s64 ktime_to_ms(const ktime_t kt)
 171 {
 172         return ktime_divns(kt, NSEC_PER_MSEC);
 173 }
 174
 175 static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)
 176 {
 177        return ktime_to_us(ktime_sub(later, earlier));
 178 }
 179
 180 static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec)
 181 {
 182         return ktime_add_ns(kt, usec * NSEC_PER_USEC);
 183 }
 184
 185 static inline ktime_t ktime_add_ms(const ktime_t kt, const u64 msec)
 186 {
 187         return ktime_add_ns(kt, msec * NSEC_PER_MSEC);
 188 }
 189
 190 static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
 191 {
 192         return ktime_sub_ns(kt, usec * NSEC_PER_USEC);
 193 }
 194
 195 extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);
 196
 197 /**
 198  * ktime_to_timespec_cond - convert a ktime_t variable to timespec
 199  *                          format only if the variable contains data
 200  * @kt:         the ktime_t variable to convert
 201  * @ts:         the timespec variable to store the result in
 202  *
 203  * Return: %true if there was a successful conversion, %false if kt was 0.
 204  */
 205 static inline __must_check bool ktime_to_timespec_cond(const ktime_t kt,
 206                                                        struct timespec *ts)
 207 {
 208         if (kt.tv64) {
 209                 *ts = ktime_to_timespec(kt);
 210                 return true;
 211         } else {
 212                 return false;
 213         }
 214 }
 215
 216 /*
 217  * The resolution of the clocks. The resolution value is returned in
 218  * the clock_getres() system call to give application programmers an
 219  * idea of the (in)accuracy of timers. Timer values are rounded up to
 220  * this resolution values.
 221  */
 222 #define LOW_RES_NSEC            TICK_NSEC
 223 #define KTIME_LOW_RES           (ktime_t){ .tv64 = LOW_RES_NSEC }
 224
 225 /* Get the monotonic time in timespec format: */
 226 extern void ktime_get_ts(struct timespec *ts);
 227
 228 /* Get the real (wall-) time in timespec format: */
 229 #define ktime_get_real_ts(ts)   getnstimeofday(ts)
 230
 231 static inline ktime_t ns_to_ktime(u64 ns)
 232 {
 233         static const ktime_t ktime_zero = { .tv64 = 0 };
 234
 235         return ktime_add_ns(ktime_zero, ns);
 236 }
 237
 238 static inline ktime_t ms_to_ktime(u64 ms)
 239 {
 240         static const ktime_t ktime_zero = { .tv64 = 0 };
 241
 242         return ktime_add_ms(ktime_zero, ms);
 243 }
 244
 245 #endif