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