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/*

 *  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>

/*

 * ktime_t:

 *

 * On 64-bit CPUs a single 64-bit variable is used to store the hrtimers

 * internal representation of time values in scalar nanoseconds. The

 * design plays out best on 64-bit CPUs, where most conversions are

 * NOPs and most arithmetic ktime_t operations are plain arithmetic

 * operations.

 *

 * On 32-bit CPUs an optimized representation of the timespec structure

 * is used to avoid expensive conversions from and to timespecs. The

 * endian-aware order of the tv struct members is choosen to allow

 * mathematical operations on the tv64 member of the union too, which

 * for certain operations produces better code.

 *

 * For architectures with efficient support for 64/32-bit conversions the

 * plain scalar nanosecond based representation can be selected by the

 * config switch CONFIG_KTIME_SCALAR.

 */

union ktime {

        s64     tv64;

#if BITS_PER_LONG != 64 && !defined(CONFIG_KTIME_SCALAR)

        struct {

# ifdef __BIG_ENDIAN

        s32     sec, nsec;

# else

        s32     nsec, sec;

# endif

        } tv;

#endif

};

typedef union ktime ktime_t;            /* Kill this */

#define KTIME_MAX                       ((s64)~((u64)1 << 63))

#if (BITS_PER_LONG == 64)

# define KTIME_SEC_MAX                  (KTIME_MAX / NSEC_PER_SEC)

#else

# define KTIME_SEC_MAX                  LONG_MAX

#endif

/*

 * ktime_t definitions when using the 64-bit scalar representation:

 */

#if (BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)

/**

 * 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 long secs, const unsigned long nsecs)

{

#if (BITS_PER_LONG == 64)

        if (unlikely(secs >= KTIME_SEC_MAX))

                return (ktime_t){ .tv64 = KTIME_MAX };

#endif

        return (ktime_t) { .tv64 = (s64)secs * NSEC_PER_SEC + (s64)nsecs };

}

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

#define ktime_sub(lhs, rhs) \

                ({ (ktime_t){ .tv64 = (lhs).tv64 - (rhs).tv64 }; })

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

#define ktime_add(lhs, rhs) \

                ({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; })

/*

 * Add a ktime_t variable and a scalar nanosecond value.

 * res = kt + nsval:

 */

#define ktime_add_ns(kt, nsval) \

                ({ (ktime_t){ .tv64 = (kt).tv64 + (nsval) }; })

/*

 * Subtract a scalar nanosecod from a ktime_t variable

 * res = kt - nsval:

 */

#define ktime_sub_ns(kt, nsval) \

                ({ (ktime_t){ .tv64 = (kt).tv64 - (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 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).tv64)

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

#define ktime_to_timeval(kt)            ns_to_timeval((kt).tv64)

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

#define ktime_to_ns(kt)                 ((kt).tv64)

#else

/*

 * Helper macros/inlines to get the ktime_t math right in the timespec

 * representation. The macros are sometimes ugly - their actual use is

 * pretty okay-ish, given the circumstances. We do all this for

 * performance reasons. The pure scalar nsec_t based code was nice and

 * simple, but created too many 64-bit / 32-bit conversions and divisions.

 *

 * Be especially aware that negative values are represented in a way

 * that the tv.sec field is negative and the tv.nsec field is greater

 * or equal to zero but less than nanoseconds per second. This is the

 * same representation which is used by timespecs.

 *

 *   tv.sec < 0 and 0 >= tv.nsec < NSEC_PER_SEC

 */

/* Set a ktime_t variable to a value in sec/nsec representation: */

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

{

        return (ktime_t) { .tv = { .sec = secs, .nsec = nsecs } };

}

/**

 * ktime_sub - subtract two ktime_t variables

 * @lhs:        minuend

 * @rhs:        subtrahend

 *

 * Returns the remainder of the substraction

 */

static inline ktime_t ktime_sub(const ktime_t lhs, const ktime_t rhs)

{

        ktime_t res;

        res.tv64 = lhs.tv64 - rhs.tv64;

        if (res.tv.nsec < 0)

                res.tv.nsec += NSEC_PER_SEC;

        return res;

}

/**

 * ktime_add - add two ktime_t variables

 * @add1:       addend1

 * @add2:       addend2

 *

 * Returns the sum of @add1 and @add2.

 */

static inline ktime_t ktime_add(const ktime_t add1, const ktime_t add2)

{

        ktime_t res;

        res.tv64 = add1.tv64 + add2.tv64;

        /*

         * performance trick: the (u32) -NSEC gives 0x00000000Fxxxxxxx

         * so we subtract NSEC_PER_SEC and add 1 to the upper 32 bit.

         *

         * it's equivalent to:

         *   tv.nsec -= NSEC_PER_SEC

         *   tv.sec ++;

         */

        if (res.tv.nsec >= NSEC_PER_SEC)

                res.tv64 += (u32)-NSEC_PER_SEC;

        return res;

}

/**

 * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable

 * @kt:         addend

 * @nsec:       the scalar nsec value to add

 *

 * Returns the sum of @kt and @nsec in ktime_t format

 */

extern ktime_t ktime_add_ns(const ktime_t kt, u64 nsec);

/**

 * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable

 * @kt:         minuend

 * @nsec:       the scalar nsec value to subtract

 *

 * Returns the subtraction of @nsec from @kt in ktime_t format

 */

extern ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec);

/**

 * timespec_to_ktime - convert a timespec to ktime_t format

 * @ts:         the timespec variable to convert

 *

 * Returns a ktime_t variable with the converted timespec value

 */

static inline ktime_t timespec_to_ktime(const struct timespec ts)

{

        return (ktime_t) { .tv = { .sec = (s32)ts.tv_sec,

                                   .nsec = (s32)ts.tv_nsec } };

}

/**

 * timeval_to_ktime - convert a timeval to ktime_t format

 * @tv:         the timeval variable to convert

 *

 * Returns a ktime_t variable with the converted timeval value

 */

static inline ktime_t timeval_to_ktime(const struct timeval tv)

{

        return (ktime_t) { .tv = { .sec = (s32)tv.tv_sec,

                                   .nsec = (s32)tv.tv_usec * 1000 } };

}

/**

 * ktime_to_timespec - convert a ktime_t variable to timespec format

 * @kt:         the ktime_t variable to convert

 *

 * Returns the timespec representation of the ktime value

 */

static inline struct timespec ktime_to_timespec(const ktime_t kt)

{

        return (struct timespec) { .tv_sec = (time_t) kt.tv.sec,

                                   .tv_nsec = (long) kt.tv.nsec };

}

/**

 * ktime_to_timeval - convert a ktime_t variable to timeval format

 * @kt:         the ktime_t variable to convert

 *

 * Returns the timeval representation of the ktime value

 */

static inline struct timeval ktime_to_timeval(const ktime_t kt)

{

        return (struct timeval) {

                .tv_sec = (time_t) kt.tv.sec,

                .tv_usec = (suseconds_t) (kt.tv.nsec / NSEC_PER_USEC) };

}

/**

 * ktime_to_ns - convert a ktime_t variable to scalar nanoseconds

 * @kt:         the ktime_t variable to convert

 *

 * Returns the scalar nanoseconds representation of @kt

 */

static inline s64 ktime_to_ns(const ktime_t kt)

{

        return (s64) kt.tv.sec * NSEC_PER_SEC + kt.tv.nsec;

}

#endif

/**

 * ktime_equal - Compares two ktime_t variables to see if they are equal

 * @cmp1:       comparable1

 * @cmp2:       comparable2

 *

 * Compare two ktime_t variables, returns 1 if equal

 */

static inline int ktime_equal(const ktime_t cmp1, const ktime_t cmp2)

{

        return cmp1.tv64 == cmp2.tv64;

}

static inline s64 ktime_to_us(const ktime_t kt)

{

        struct timeval tv = ktime_to_timeval(kt);

        return (s64) tv.tv_sec * USEC_PER_SEC + tv.tv_usec;

}

static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)

{

       return ktime_to_us(ktime_sub(later, earlier));

}

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

{

        return ktime_add_ns(kt, usec * 1000);

}

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

{

        return ktime_sub_ns(kt, usec * 1000);

}

/*

 * 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 KTIME_LOW_RES           (ktime_t){ .tv64 = TICK_NSEC }

/* Get the monotonic time in timespec format: */

extern void ktime_get_ts(struct timespec *ts);

/* Get the real (wall-) time in timespec format: */

#define ktime_get_real_ts(ts)   getnstimeofday(ts)

#endif