/*
   *  include/linux/ktime.h
   *
   *  ktime_t - nanosecond-resolution time format.
   *
   *   Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
   *   Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
   *
   *  data type definitions, declarations, prototypes and macros.
   *
   *  Started by: Thomas Gleixner and Ingo Molnar
   *

   *  Credits:
   *
   *  	Roman Zippel provided the ideas and primary code snippets of
   *  	the ktime_t union and further simplifications of the original
   *  	code.
   *

   *  For licencing details see kernel-base/COPYING
   */
  #ifndef _LINUX_KTIME_H
  #define _LINUX_KTIME_H
  
  #include <linux/time.h>
  #include <linux/jiffies.h>

  /* Nanosecond scalar representation for kernel time values */
  typedef s64	ktime_t;

  /**
   * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value

   * @secs:	seconds to set
   * @nsecs:	nanoseconds to set
   *

   * Return: The ktime_t representation of the value.

   */

  static inline ktime_t ktime_set(const s64 secs, const unsigned long nsecs)

  {

  	if (unlikely(secs >= KTIME_SEC_MAX))

  		return KTIME_MAX;

  	return secs * NSEC_PER_SEC + (s64)nsecs;

  }
  
  /* Subtract two ktime_t variables. rem = lhs -rhs: */

  #define ktime_sub(lhs, rhs)	((lhs) - (rhs))

  
  /* Add two ktime_t variables. res = lhs + rhs: */

  #define ktime_add(lhs, rhs)	((lhs) + (rhs))

  
  /*

   * Same as ktime_add(), but avoids undefined behaviour on overflow; however,
   * this means that you must check the result for overflow yourself.
   */

  #define ktime_add_unsafe(lhs, rhs)	((u64) (lhs) + (rhs))

  
  /*

   * Add a ktime_t variable and a scalar nanosecond value.
   * res = kt + nsval:
   */

  #define ktime_add_ns(kt, nsval)		((kt) + (nsval))

  /*
   * Subtract a scalar nanosecod from a ktime_t variable
   * res = kt - nsval:
   */

  #define ktime_sub_ns(kt, nsval)		((kt) - (nsval))

  /* convert a timespec to ktime_t format: */

  static inline ktime_t timespec_to_ktime(struct timespec ts)
  {
  	return ktime_set(ts.tv_sec, ts.tv_nsec);
  }

  /* convert a timespec64 to ktime_t format: */
  static inline ktime_t timespec64_to_ktime(struct timespec64 ts)
  {
  	return ktime_set(ts.tv_sec, ts.tv_nsec);
  }

  /* convert a timeval to ktime_t format: */

  static inline ktime_t timeval_to_ktime(struct timeval tv)
  {
  	return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
  }

  
  /* Map the ktime_t to timespec conversion to ns_to_timespec function */

  #define ktime_to_timespec(kt)		ns_to_timespec((kt))

  /* Map the ktime_t to timespec conversion to ns_to_timespec function */

  #define ktime_to_timespec64(kt)		ns_to_timespec64((kt))

  /* Map the ktime_t to timeval conversion to ns_to_timeval function */

  #define ktime_to_timeval(kt)		ns_to_timeval((kt))

  /* Convert ktime_t to nanoseconds - NOP in the scalar storage format: */

  #define ktime_to_ns(kt)			(kt)

  /**
   * ktime_compare - Compares two ktime_t variables for less, greater or equal
   * @cmp1:	comparable1
   * @cmp2:	comparable2
   *

   * Return: ...

   *   cmp1  < cmp2: return <0
   *   cmp1 == cmp2: return 0
   *   cmp1  > cmp2: return >0
   */
  static inline int ktime_compare(const ktime_t cmp1, const ktime_t cmp2)
  {

  	if (cmp1 < cmp2)

  		return -1;

  	if (cmp1 > cmp2)

  		return 1;
  	return 0;
  }

  /**
   * ktime_after - Compare if a ktime_t value is bigger than another one.
   * @cmp1:	comparable1
   * @cmp2:	comparable2
   *
   * Return: true if cmp1 happened after cmp2.
   */
  static inline bool ktime_after(const ktime_t cmp1, const ktime_t cmp2)
  {
  	return ktime_compare(cmp1, cmp2) > 0;
  }
  
  /**
   * ktime_before - Compare if a ktime_t value is smaller than another one.
   * @cmp1:	comparable1
   * @cmp2:	comparable2
   *
   * Return: true if cmp1 happened before cmp2.
   */
  static inline bool ktime_before(const ktime_t cmp1, const ktime_t cmp2)
  {
  	return ktime_compare(cmp1, cmp2) < 0;
  }

  #if BITS_PER_LONG < 64

  extern s64 __ktime_divns(const ktime_t kt, s64 div);
  static inline s64 ktime_divns(const ktime_t kt, s64 div)

  {

  	/*
  	 * Negative divisors could cause an inf loop,
  	 * so bug out here.
  	 */
  	BUG_ON(div < 0);

  	if (__builtin_constant_p(div) && !(div >> 32)) {

  		s64 ns = kt;

  		u64 tmp = ns < 0 ? -ns : ns;
  
  		do_div(tmp, div);
  		return ns < 0 ? -tmp : tmp;

  	} else {
  		return __ktime_divns(kt, div);
  	}
  }

  #else /* BITS_PER_LONG < 64 */

  static inline s64 ktime_divns(const ktime_t kt, s64 div)
  {
  	/*
  	 * 32-bit implementation cannot handle negative divisors,
  	 * so catch them on 64bit as well.
  	 */
  	WARN_ON(div < 0);

  	return kt / div;

  }

  #endif

  static inline s64 ktime_to_us(const ktime_t kt)
  {

  	return ktime_divns(kt, NSEC_PER_USEC);

  }

  static inline s64 ktime_to_ms(const ktime_t kt)
  {

  	return ktime_divns(kt, NSEC_PER_MSEC);

  }

  static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)
  {
         return ktime_to_us(ktime_sub(later, earlier));
  }

  static inline s64 ktime_ms_delta(const ktime_t later, const ktime_t earlier)
  {
  	return ktime_to_ms(ktime_sub(later, earlier));
  }

  static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec)
  {

  	return ktime_add_ns(kt, usec * NSEC_PER_USEC);

  }

  static inline ktime_t ktime_add_ms(const ktime_t kt, const u64 msec)
  {
  	return ktime_add_ns(kt, msec * NSEC_PER_MSEC);
  }

  static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
  {

  	return ktime_sub_ns(kt, usec * NSEC_PER_USEC);

  }

  static inline ktime_t ktime_sub_ms(const ktime_t kt, const u64 msec)
  {
  	return ktime_sub_ns(kt, msec * NSEC_PER_MSEC);
  }

  extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);

  /**
   * ktime_to_timespec_cond - convert a ktime_t variable to timespec
   *			    format only if the variable contains data
   * @kt:		the ktime_t variable to convert
   * @ts:		the timespec variable to store the result in
   *

   * Return: %true if there was a successful conversion, %false if kt was 0.

   */

  static inline __must_check bool ktime_to_timespec_cond(const ktime_t kt,
  						       struct timespec *ts)

  {

  	if (kt) {

  		*ts = ktime_to_timespec(kt);
  		return true;
  	} else {
  		return false;
  	}
  }

  /**
   * ktime_to_timespec64_cond - convert a ktime_t variable to timespec64
   *			    format only if the variable contains data
   * @kt:		the ktime_t variable to convert
   * @ts:		the timespec variable to store the result in
   *
   * Return: %true if there was a successful conversion, %false if kt was 0.
   */
  static inline __must_check bool ktime_to_timespec64_cond(const ktime_t kt,
  						       struct timespec64 *ts)
  {

  	if (kt) {

  		*ts = ktime_to_timespec64(kt);
  		return true;
  	} else {
  		return false;
  	}
  }

  /*
   * The resolution of the clocks. The resolution value is returned in
   * the clock_getres() system call to give application programmers an
   * idea of the (in)accuracy of timers. Timer values are rounded up to
   * this resolution values.
   */

  #define LOW_RES_NSEC		TICK_NSEC

  #define KTIME_LOW_RES		(LOW_RES_NSEC)

  static inline ktime_t ns_to_ktime(u64 ns)
  {

  	return ns;

  }

  static inline ktime_t ms_to_ktime(u64 ms)
  {

  	return ms * NSEC_PER_MSEC;

  }

  # include <linux/timekeeping.h>

  #endif