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