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 timespec64 to ktime_t format: */
  87 static inline ktime_t timespec64_to_ktime(struct timespec64 ts)
  88 {
  89         return ktime_set(ts.tv_sec, ts.tv_nsec);
  90 }
  91
  92 /* convert a timeval to ktime_t format: */
  93 static inline ktime_t timeval_to_ktime(struct timeval tv)
  94 {
  95         return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
  96 }
  97
  98 /* Map the ktime_t to timespec conversion to ns_to_timespec function */
  99 #define ktime_to_timespec(kt)           ns_to_timespec((kt).tv64)
 100
 101 /* Map the ktime_t to timespec conversion to ns_to_timespec function */
 102 #define ktime_to_timespec64(kt)         ns_to_timespec64((kt).tv64)
 103
 104 /* Map the ktime_t to timeval conversion to ns_to_timeval function */
 105 #define ktime_to_timeval(kt)            ns_to_timeval((kt).tv64)
 106
 107 /* Convert ktime_t to nanoseconds - NOP in the scalar storage format: */
 108 #define ktime_to_ns(kt)                 ((kt).tv64)
 109
 110
 111 /**
 112  * ktime_equal - Compares two ktime_t variables to see if they are equal
 113  * @cmp1:       comparable1
 114  * @cmp2:       comparable2
 115  *
 116  * Compare two ktime_t variables.
 117  *
 118  * Return: 1 if equal.
 119  */
 120 static inline int ktime_equal(const ktime_t cmp1, const ktime_t cmp2)
 121 {
 122         return cmp1.tv64 == cmp2.tv64;
 123 }
 124
 125 /**
 126  * ktime_compare - Compares two ktime_t variables for less, greater or equal
 127  * @cmp1:       comparable1
 128  * @cmp2:       comparable2
 129  *
 130  * Return: ...
 131  *   cmp1  < cmp2: return <0
 132  *   cmp1 == cmp2: return 0
 133  *   cmp1  > cmp2: return >0
 134  */
 135 static inline int ktime_compare(const ktime_t cmp1, const ktime_t cmp2)
 136 {
 137         if (cmp1.tv64 < cmp2.tv64)
 138                 return -1;
 139         if (cmp1.tv64 > cmp2.tv64)
 140                 return 1;
 141         return 0;
 142 }
 143
 144 /**
 145  * ktime_after - Compare if a ktime_t value is bigger than another one.
 146  * @cmp1:       comparable1
 147  * @cmp2:       comparable2
 148  *
 149  * Return: true if cmp1 happened after cmp2.
 150  */
 151 static inline bool ktime_after(const ktime_t cmp1, const ktime_t cmp2)
 152 {
 153         return ktime_compare(cmp1, cmp2) > 0;
 154 }
 155
 156 /**
 157  * ktime_before - Compare if a ktime_t value is smaller than another one.
 158  * @cmp1:       comparable1
 159  * @cmp2:       comparable2
 160  *
 161  * Return: true if cmp1 happened before cmp2.
 162  */
 163 static inline bool ktime_before(const ktime_t cmp1, const ktime_t cmp2)
 164 {
 165         return ktime_compare(cmp1, cmp2) < 0;
 166 }
 167
 168 #if BITS_PER_LONG < 64
 169 extern s64 __ktime_divns(const ktime_t kt, s64 div);
 170 static inline s64 ktime_divns(const ktime_t kt, s64 div)
 171 {
 172         /*
 173          * Negative divisors could cause an inf loop,
 174          * so bug out here.
 175          */
 176         BUG_ON(div < 0);
 177         if (__builtin_constant_p(div) && !(div >> 32)) {
 178                 s64 ns = kt.tv64;
 179                 u64 tmp = ns < 0 ? -ns : ns;
 180
 181                 do_div(tmp, div);
 182                 return ns < 0 ? -tmp : tmp;
 183         } else {
 184                 return __ktime_divns(kt, div);
 185         }
 186 }
 187 #else /* BITS_PER_LONG < 64 */
 188 static inline s64 ktime_divns(const ktime_t kt, s64 div)
 189 {
 190         /*
 191          * 32-bit implementation cannot handle negative divisors,
 192          * so catch them on 64bit as well.
 193          */
 194         WARN_ON(div < 0);
 195         return kt.tv64 / div;
 196 }
 197 #endif
 198
 199 static inline s64 ktime_to_us(const ktime_t kt)
 200 {
 201         return ktime_divns(kt, NSEC_PER_USEC);
 202 }
 203
 204 static inline s64 ktime_to_ms(const ktime_t kt)
 205 {
 206         return ktime_divns(kt, NSEC_PER_MSEC);
 207 }
 208
 209 static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)
 210 {
 211        return ktime_to_us(ktime_sub(later, earlier));
 212 }
 213
 214 static inline s64 ktime_ms_delta(const ktime_t later, const ktime_t earlier)
 215 {
 216         return ktime_to_ms(ktime_sub(later, earlier));
 217 }
 218
 219 static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec)
 220 {
 221         return ktime_add_ns(kt, usec * NSEC_PER_USEC);
 222 }
 223
 224 static inline ktime_t ktime_add_ms(const ktime_t kt, const u64 msec)
 225 {
 226         return ktime_add_ns(kt, msec * NSEC_PER_MSEC);
 227 }
 228
 229 static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
 230 {
 231         return ktime_sub_ns(kt, usec * NSEC_PER_USEC);
 232 }
 233
 234 extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);
 235
 236 /**
 237  * ktime_to_timespec_cond - convert a ktime_t variable to timespec
 238  *                          format only if the variable contains data
 239  * @kt:         the ktime_t variable to convert
 240  * @ts:         the timespec variable to store the result in
 241  *
 242  * Return: %true if there was a successful conversion, %false if kt was 0.
 243  */
 244 static inline __must_check bool ktime_to_timespec_cond(const ktime_t kt,
 245                                                        struct timespec *ts)
 246 {
 247         if (kt.tv64) {
 248                 *ts = ktime_to_timespec(kt);
 249                 return true;
 250         } else {
 251                 return false;
 252         }
 253 }
 254
 255 /**
 256  * ktime_to_timespec64_cond - convert a ktime_t variable to timespec64
 257  *                          format only if the variable contains data
 258  * @kt:         the ktime_t variable to convert
 259  * @ts:         the timespec variable to store the result in
 260  *
 261  * Return: %true if there was a successful conversion, %false if kt was 0.
 262  */
 263 static inline __must_check bool ktime_to_timespec64_cond(const ktime_t kt,
 264                                                        struct timespec64 *ts)
 265 {
 266         if (kt.tv64) {
 267                 *ts = ktime_to_timespec64(kt);
 268                 return true;
 269         } else {
 270                 return false;
 271         }
 272 }
 273
 274 /*
 275  * The resolution of the clocks. The resolution value is returned in
 276  * the clock_getres() system call to give application programmers an
 277  * idea of the (in)accuracy of timers. Timer values are rounded up to
 278  * this resolution values.
 279  */
 280 #define LOW_RES_NSEC            TICK_NSEC
 281 #define KTIME_LOW_RES           (ktime_t){ .tv64 = LOW_RES_NSEC }
 282
 283 static inline ktime_t ns_to_ktime(u64 ns)
 284 {
 285         static const ktime_t ktime_zero = { .tv64 = 0 };
 286
 287         return ktime_add_ns(ktime_zero, ns);
 288 }
 289
 290 static inline ktime_t ms_to_ktime(u64 ms)
 291 {
 292         static const ktime_t ktime_zero = { .tv64 = 0 };
 293
 294         return ktime_add_ms(ktime_zero, ms);
 295 }
 296
 297 # include <linux/timekeeping.h>
 298
 299 #endif