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 /* Nanosecond scalar representation for kernel time values */
  28 typedef s64     ktime_t;
  29
  30 /**
  31  * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value
  32  * @secs:       seconds to set
  33  * @nsecs:      nanoseconds to set
  34  *
  35  * Return: The ktime_t representation of the value.
  36  */
  37 static inline ktime_t ktime_set(const s64 secs, const unsigned long nsecs)
  38 {
  39         if (unlikely(secs >= KTIME_SEC_MAX))
  40                 return KTIME_MAX;
  41
  42         return secs * NSEC_PER_SEC + (s64)nsecs;
  43 }
  44
  45 /* Subtract two ktime_t variables. rem = lhs -rhs: */
  46 #define ktime_sub(lhs, rhs)     ((lhs) - (rhs))
  47
  48 /* Add two ktime_t variables. res = lhs + rhs: */
  49 #define ktime_add(lhs, rhs)     ((lhs) + (rhs))
  50
  51 /*
  52  * Same as ktime_add(), but avoids undefined behaviour on overflow; however,
  53  * this means that you must check the result for overflow yourself.
  54  */
  55 #define ktime_add_unsafe(lhs, rhs)      ((u64) (lhs) + (rhs))
  56
  57 /*
  58  * Add a ktime_t variable and a scalar nanosecond value.
  59  * res = kt + nsval:
  60  */
  61 #define ktime_add_ns(kt, nsval)         ((kt) + (nsval))
  62
  63 /*
  64  * Subtract a scalar nanosecod from a ktime_t variable
  65  * res = kt - nsval:
  66  */
  67 #define ktime_sub_ns(kt, nsval)         ((kt) - (nsval))
  68
  69 /* convert a timespec to ktime_t format: */
  70 static inline ktime_t timespec_to_ktime(struct timespec ts)
  71 {
  72         return ktime_set(ts.tv_sec, ts.tv_nsec);
  73 }
  74
  75 /* convert a timespec64 to ktime_t format: */
  76 static inline ktime_t timespec64_to_ktime(struct timespec64 ts)
  77 {
  78         return ktime_set(ts.tv_sec, ts.tv_nsec);
  79 }
  80
  81 /* convert a timeval to ktime_t format: */
  82 static inline ktime_t timeval_to_ktime(struct timeval tv)
  83 {
  84         return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
  85 }
  86
  87 /* Map the ktime_t to timespec conversion to ns_to_timespec function */
  88 #define ktime_to_timespec(kt)           ns_to_timespec((kt))
  89
  90 /* Map the ktime_t to timespec conversion to ns_to_timespec function */
  91 #define ktime_to_timespec64(kt)         ns_to_timespec64((kt))
  92
  93 /* Map the ktime_t to timeval conversion to ns_to_timeval function */
  94 #define ktime_to_timeval(kt)            ns_to_timeval((kt))
  95
  96 /* Convert ktime_t to nanoseconds */
  97 static inline s64 ktime_to_ns(const ktime_t kt)
  98 {
  99         return kt;
 100 }
 101
 102 /**
 103  * ktime_compare - Compares two ktime_t variables for less, greater or equal
 104  * @cmp1:       comparable1
 105  * @cmp2:       comparable2
 106  *
 107  * Return: ...
 108  *   cmp1  < cmp2: return <0
 109  *   cmp1 == cmp2: return 0
 110  *   cmp1  > cmp2: return >0
 111  */
 112 static inline int ktime_compare(const ktime_t cmp1, const ktime_t cmp2)
 113 {
 114         if (cmp1 < cmp2)
 115                 return -1;
 116         if (cmp1 > cmp2)
 117                 return 1;
 118         return 0;
 119 }
 120
 121 /**
 122  * ktime_after - Compare if a ktime_t value is bigger than another one.
 123  * @cmp1:       comparable1
 124  * @cmp2:       comparable2
 125  *
 126  * Return: true if cmp1 happened after cmp2.
 127  */
 128 static inline bool ktime_after(const ktime_t cmp1, const ktime_t cmp2)
 129 {
 130         return ktime_compare(cmp1, cmp2) > 0;
 131 }
 132
 133 /**
 134  * ktime_before - Compare if a ktime_t value is smaller than another one.
 135  * @cmp1:       comparable1
 136  * @cmp2:       comparable2
 137  *
 138  * Return: true if cmp1 happened before cmp2.
 139  */
 140 static inline bool ktime_before(const ktime_t cmp1, const ktime_t cmp2)
 141 {
 142         return ktime_compare(cmp1, cmp2) < 0;
 143 }
 144
 145 #if BITS_PER_LONG < 64
 146 extern s64 __ktime_divns(const ktime_t kt, s64 div);
 147 static inline s64 ktime_divns(const ktime_t kt, s64 div)
 148 {
 149         /*
 150          * Negative divisors could cause an inf loop,
 151          * so bug out here.
 152          */
 153         BUG_ON(div < 0);
 154         if (__builtin_constant_p(div) && !(div >> 32)) {
 155                 s64 ns = kt;
 156                 u64 tmp = ns < 0 ? -ns : ns;
 157
 158                 do_div(tmp, div);
 159                 return ns < 0 ? -tmp : tmp;
 160         } else {
 161                 return __ktime_divns(kt, div);
 162         }
 163 }
 164 #else /* BITS_PER_LONG < 64 */
 165 static inline s64 ktime_divns(const ktime_t kt, s64 div)
 166 {
 167         /*
 168          * 32-bit implementation cannot handle negative divisors,
 169          * so catch them on 64bit as well.
 170          */
 171         WARN_ON(div < 0);
 172         return kt / div;
 173 }
 174 #endif
 175
 176 static inline s64 ktime_to_us(const ktime_t kt)
 177 {
 178         return ktime_divns(kt, NSEC_PER_USEC);
 179 }
 180
 181 static inline s64 ktime_to_ms(const ktime_t kt)
 182 {
 183         return ktime_divns(kt, NSEC_PER_MSEC);
 184 }
 185
 186 static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)
 187 {
 188        return ktime_to_us(ktime_sub(later, earlier));
 189 }
 190
 191 static inline s64 ktime_ms_delta(const ktime_t later, const ktime_t earlier)
 192 {
 193         return ktime_to_ms(ktime_sub(later, earlier));
 194 }
 195
 196 static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec)
 197 {
 198         return ktime_add_ns(kt, usec * NSEC_PER_USEC);
 199 }
 200
 201 static inline ktime_t ktime_add_ms(const ktime_t kt, const u64 msec)
 202 {
 203         return ktime_add_ns(kt, msec * NSEC_PER_MSEC);
 204 }
 205
 206 static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
 207 {
 208         return ktime_sub_ns(kt, usec * NSEC_PER_USEC);
 209 }
 210
 211 static inline ktime_t ktime_sub_ms(const ktime_t kt, const u64 msec)
 212 {
 213         return ktime_sub_ns(kt, msec * NSEC_PER_MSEC);
 214 }
 215
 216 extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);
 217
 218 /**
 219  * ktime_to_timespec_cond - convert a ktime_t variable to timespec
 220  *                          format only if the variable contains data
 221  * @kt:         the ktime_t variable to convert
 222  * @ts:         the timespec variable to store the result in
 223  *
 224  * Return: %true if there was a successful conversion, %false if kt was 0.
 225  */
 226 static inline __must_check bool ktime_to_timespec_cond(const ktime_t kt,
 227                                                        struct timespec *ts)
 228 {
 229         if (kt) {
 230                 *ts = ktime_to_timespec(kt);
 231                 return true;
 232         } else {
 233                 return false;
 234         }
 235 }
 236
 237 /**
 238  * ktime_to_timespec64_cond - convert a ktime_t variable to timespec64
 239  *                          format only if the variable contains data
 240  * @kt:         the ktime_t variable to convert
 241  * @ts:         the timespec variable to store the result in
 242  *
 243  * Return: %true if there was a successful conversion, %false if kt was 0.
 244  */
 245 static inline __must_check bool ktime_to_timespec64_cond(const ktime_t kt,
 246                                                        struct timespec64 *ts)
 247 {
 248         if (kt) {
 249                 *ts = ktime_to_timespec64(kt);
 250                 return true;
 251         } else {
 252                 return false;
 253         }
 254 }
 255
 256 /*
 257  * The resolution of the clocks. The resolution value is returned in
 258  * the clock_getres() system call to give application programmers an
 259  * idea of the (in)accuracy of timers. Timer values are rounded up to
 260  * this resolution values.
 261  */
 262 #define LOW_RES_NSEC            TICK_NSEC
 263 #define KTIME_LOW_RES           (LOW_RES_NSEC)
 264
 265 static inline ktime_t ns_to_ktime(u64 ns)
 266 {
 267         return ns;
 268 }
 269
 270 static inline ktime_t ms_to_ktime(u64 ms)
 271 {
 272         return ms * NSEC_PER_MSEC;
 273 }
 274
 275 # include <linux/timekeeping.h>
 276 # include <linux/timekeeping32.h>
 277
 278 #endif