/* SPDX-License-Identifier: GPL-2.0 */

#ifndef _LINUX_JIFFIES_H

#define _LINUX_JIFFIES_H

#include <linux/cache.h>

#include <linux/limits.h>

#include <linux/math64.h>

#include <linux/minmax.h>

#include <linux/types.h>

#include <linux/time.h>

#include <linux/timex.h>

#include <vdso/jiffies.h>

#include <asm/param.h> /* for HZ */

#include <generated/timeconst.h>

/*

* The following defines establish the engineering parameters of the PLL

* model. The HZ variable establishes the timer interrupt frequency, 100 Hz

* for the SunOS kernel, 256 Hz for the Ultrix kernel and 1024 Hz for the

* OSF/1 kernel. The SHIFT_HZ define expresses the same value as the

* nearest power of two in order to avoid hardware multiply operations.

*/

#if HZ >= 12 && HZ < 24

# define SHIFT_HZ 4

#elif HZ >= 24 && HZ < 48

# define SHIFT_HZ 5

#elif HZ >= 48 && HZ < 96

# define SHIFT_HZ 6

#elif HZ >= 96 && HZ < 192

# define SHIFT_HZ 7

#elif HZ >= 192 && HZ < 384

# define SHIFT_HZ 8

#elif HZ >= 384 && HZ < 768

# define SHIFT_HZ 9

#elif HZ >= 768 && HZ < 1536

# define SHIFT_HZ 10

#elif HZ >= 1536 && HZ < 3072

# define SHIFT_HZ 11

#elif HZ >= 3072 && HZ < 6144

# define SHIFT_HZ 12

#elif HZ >= 6144 && HZ < 12288

# define SHIFT_HZ 13

#else

# error Invalid value of HZ.

#endif

/* Suppose we want to divide two numbers NOM and DEN: NOM/DEN, then we can

* improve accuracy by shifting LSH bits, hence calculating:

* (NOM << LSH) / DEN

* This however means trouble for large NOM, because (NOM << LSH) may no

* longer fit in 32 bits. The following way of calculating this gives us

* some slack, under the following conditions:

* - (NOM / DEN) fits in (32 - LSH) bits.

* - (NOM % DEN) fits in (32 - LSH) bits.

*/

#define SH_DIV(NOM,DEN,LSH) ( (((NOM) / (DEN)) << (LSH)) \

+ ((((NOM) % (DEN)) << (LSH)) + (DEN) / 2) / (DEN))

/* LATCH is used in the interval timer and ftape setup. */

#define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ) /* For divider */

extern int register_refined_jiffies(long clock_tick_rate);

/* TICK_USEC is the time between ticks in usec assuming SHIFTED_HZ */

#define TICK_USEC ((USEC_PER_SEC + HZ/2) / HZ)

/* USER_TICK_USEC is the time between ticks in usec assuming fake USER_HZ */

#define USER_TICK_USEC ((1000000UL + USER_HZ/2) / USER_HZ)

#ifndef __jiffy_arch_data

#define __jiffy_arch_data

#endif

/*

* The 64-bit value is not atomic - you MUST NOT read it

* without sampling the sequence number in jiffies_lock.

* get_jiffies_64() will do this for you as appropriate.

*/

extern u64 __cacheline_aligned_in_smp jiffies_64;

extern unsigned long volatile __cacheline_aligned_in_smp __jiffy_arch_data jiffies;

#if (BITS_PER_LONG < 64)

u64 get_jiffies_64(void);

#else

static inline u64 get_jiffies_64(void)

{

return (u64)jiffies;

}

#endif

/*

* These inlines deal with timer wrapping correctly. You are

* strongly encouraged to use them

* 1. Because people otherwise forget

* 2. Because if the timer wrap changes in future you won't have to

* alter your driver code.

*

* time_after(a,b) returns true if the time a is after time b.

*

* Do this with "<0" and ">=0" to only test the sign of the result. A

* good compiler would generate better code (and a really good compiler

* wouldn't care). Gcc is currently neither.

*/

#define time_after(a,b) \

(typecheck(unsigned long, a) && \

typecheck(unsigned long, b) && \

((long)((b) - (a)) < 0))

#define time_before(a,b) time_after(b,a)

#define time_after_eq(a,b) \

(typecheck(unsigned long, a) && \

typecheck(unsigned long, b) && \

((long)((a) - (b)) >= 0))

#define time_before_eq(a,b) time_after_eq(b,a)

/*

* Calculate whether a is in the range of [b, c].

*/

#define time_in_range(a,b,c) \

(time_after_eq(a,b) && \

time_before_eq(a,c))

/*

* Calculate whether a is in the range of [b, c).

*/

#define time_in_range_open(a,b,c) \

(time_after_eq(a,b) && \

time_before(a,c))

/* Same as above, but does so with platform independent 64bit types.

* These must be used when utilizing jiffies_64 (i.e. return value of

* get_jiffies_64() */

#define time_after64(a,b) \

(typecheck(__u64, a) && \

typecheck(__u64, b) && \

((__s64)((b) - (a)) < 0))

#define time_before64(a,b) time_after64(b,a)

#define time_after_eq64(a,b) \

(typecheck(__u64, a) && \

typecheck(__u64, b) && \

((__s64)((a) - (b)) >= 0))

#define time_before_eq64(a,b) time_after_eq64(b,a)

#define time_in_range64(a, b, c) \

(time_after_eq64(a, b) && \

time_before_eq64(a, c))

/*

* These four macros compare jiffies and 'a' for convenience.

*/

/* time_is_before_jiffies(a) return true if a is before jiffies */

#define time_is_before_jiffies(a) time_after(jiffies, a)

#define time_is_before_jiffies64(a) time_after64(get_jiffies_64(), a)

/* time_is_after_jiffies(a) return true if a is after jiffies */

#define time_is_after_jiffies(a) time_before(jiffies, a)

#define time_is_after_jiffies64(a) time_before64(get_jiffies_64(), a)

/* time_is_before_eq_jiffies(a) return true if a is before or equal to jiffies*/

#define time_is_before_eq_jiffies(a) time_after_eq(jiffies, a)

#define time_is_before_eq_jiffies64(a) time_after_eq64(get_jiffies_64(), a)

/* time_is_after_eq_jiffies(a) return true if a is after or equal to jiffies*/

#define time_is_after_eq_jiffies(a) time_before_eq(jiffies, a)

#define time_is_after_eq_jiffies64(a) time_before_eq64(get_jiffies_64(), a)

/*

* Have the 32 bit jiffies value wrap 5 minutes after boot

* so jiffies wrap bugs show up earlier.

*/

#define INITIAL_JIFFIES ((unsigned long)(unsigned int) (-300*HZ))

/*

* Change timeval to jiffies, trying to avoid the

* most obvious overflows..

*

* And some not so obvious.

*

* Note that we don't want to return LONG_MAX, because

* for various timeout reasons we often end up having

* to wait "jiffies+1" in order to guarantee that we wait

* at _least_ "jiffies" - so "jiffies+1" had better still

* be positive.

*/

#define MAX_JIFFY_OFFSET ((LONG_MAX >> 1)-1)

extern unsigned long preset_lpj;

/*

* We want to do realistic conversions of time so we need to use the same

* values the update wall clock code uses as the jiffies size. This value

* is: TICK_NSEC (which is defined in timex.h). This

* is a constant and is in nanoseconds. We will use scaled math

* with a set of scales defined here as SEC_JIFFIE_SC, USEC_JIFFIE_SC and

* NSEC_JIFFIE_SC. Note that these defines contain nothing but

* constants and so are computed at compile time. SHIFT_HZ (computed in

* timex.h) adjusts the scaling for different HZ values.

* Scaled math??? What is that?

*

* Scaled math is a way to do integer math on values that would,

* otherwise, either overflow, underflow, or cause undesired div

* instructions to appear in the execution path. In short, we "scale"

* up the operands so they take more bits (more precision, less

* underflow), do the desired operation and then "scale" the result back

* by the same amount. If we do the scaling by shifting we avoid the

* costly mpy and the dastardly div instructions.

* Suppose, for example, we want to convert from seconds to jiffies

* where jiffies is defined in nanoseconds as NSEC_PER_JIFFIE. The

* simple math is: jiff = (sec * NSEC_PER_SEC) / NSEC_PER_JIFFIE; We

* observe that (NSEC_PER_SEC / NSEC_PER_JIFFIE) is a constant which we

* might calculate at compile time, however, the result will only have

* about 3-4 bits of precision (less for smaller values of HZ).

*

* So, we scale as follows:

* jiff = (sec) * (NSEC_PER_SEC / NSEC_PER_JIFFIE);

* jiff = ((sec) * ((NSEC_PER_SEC * SCALE)/ NSEC_PER_JIFFIE)) / SCALE;

* Then we make SCALE a power of two so:

* jiff = ((sec) * ((NSEC_PER_SEC << SCALE)/ NSEC_PER_JIFFIE)) >> SCALE;

* Now we define:

* #define SEC_CONV = ((NSEC_PER_SEC << SCALE)/ NSEC_PER_JIFFIE))

* jiff = (sec * SEC_CONV) >> SCALE;

*

* Often the math we use will expand beyond 32-bits so we tell C how to

* do this and pass the 64-bit result of the mpy through the ">> SCALE"

* which should take the result back to 32-bits. We want this expansion

* to capture as much precision as possible. At the same time we don't

* want to overflow so we pick the SCALE to avoid this. In this file,

* that means using a different scale for each range of HZ values (as

* defined in timex.h).

*

* For those who want to know, gcc will give a 64-bit result from a "*"

* operator if the result is a long long AND at least one of the

* operands is cast to long long (usually just prior to the "*" so as

* not to confuse it into thinking it really has a 64-bit operand,

* which, buy the way, it can do, but it takes more code and at least 2

* mpys).

* We also need to be aware that one second in nanoseconds is only a

* couple of bits away from overflowing a 32-bit word, so we MUST use

* 64-bits to get the full range time in nanoseconds.

*/

/*

* Here are the scales we will use. One for seconds, nanoseconds and

* microseconds.

*

* Within the limits of cpp we do a rough cut at the SEC_JIFFIE_SC and

* check if the sign bit is set. If not, we bump the shift count by 1.

* (Gets an extra bit of precision where we can use it.)

* We know it is set for HZ = 1024 and HZ = 100 not for 1000.

* Haven't tested others.

* Limits of cpp (for #if expressions) only long (no long long), but

* then we only need the most signicant bit.

*/

#define SEC_JIFFIE_SC (31 - SHIFT_HZ)

#if !((((NSEC_PER_SEC << 2) / TICK_NSEC) << (SEC_JIFFIE_SC - 2)) & 0x80000000)

#undef SEC_JIFFIE_SC

#define SEC_JIFFIE_SC (32 - SHIFT_HZ)

#endif

#define NSEC_JIFFIE_SC (SEC_JIFFIE_SC + 29)

#define SEC_CONVERSION ((unsigned long)((((u64)NSEC_PER_SEC << SEC_JIFFIE_SC) +\

TICK_NSEC -1) / (u64)TICK_NSEC))

#define NSEC_CONVERSION ((unsigned long)((((u64)1 << NSEC_JIFFIE_SC) +\

TICK_NSEC -1) / (u64)TICK_NSEC))

/*

* The maximum jiffie value is (MAX_INT >> 1). Here we translate that

* into seconds. The 64-bit case will overflow if we are not careful,

* so use the messy SH_DIV macro to do it. Still all constants.

*/

#if BITS_PER_LONG < 64

# define MAX_SEC_IN_JIFFIES \

(long)((u64)((u64)MAX_JIFFY_OFFSET * TICK_NSEC) / NSEC_PER_SEC)

#else /* take care of overflow on 64 bits machines */

# define MAX_SEC_IN_JIFFIES \

(SH_DIV((MAX_JIFFY_OFFSET >> SEC_JIFFIE_SC) * TICK_NSEC, NSEC_PER_SEC, 1) - 1)

#endif

/*

* Convert various time units to each other:

*/

extern unsigned int jiffies_to_msecs(const unsigned long j);

extern unsigned int jiffies_to_usecs(const unsigned long j);

static inline u64 jiffies_to_nsecs(const unsigned long j)

{

return (u64)jiffies_to_usecs(j) * NSEC_PER_USEC;

}

extern u64 jiffies64_to_nsecs(u64 j);

extern u64 jiffies64_to_msecs(u64 j);

extern unsigned long __msecs_to_jiffies(const unsigned int m);

#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)

/*

* HZ is equal to or smaller than 1000, and 1000 is a nice round

* multiple of HZ, divide with the factor between them, but round

* upwards:

*/

static inline unsigned long _msecs_to_jiffies(const unsigned int m)

{

return (m + (MSEC_PER_SEC / HZ) - 1) / (MSEC_PER_SEC / HZ);

}

#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)

/*

* HZ is larger than 1000, and HZ is a nice round multiple of 1000 -

* simply multiply with the factor between them.

*

* But first make sure the multiplication result cannot overflow:

*/

static inline unsigned long _msecs_to_jiffies(const unsigned int m)

{

if (m > jiffies_to_msecs(MAX_JIFFY_OFFSET))

return MAX_JIFFY_OFFSET;

return m * (HZ / MSEC_PER_SEC);

}

#else

/*

* Generic case - multiply, round and divide. But first check that if

* we are doing a net multiplication, that we wouldn't overflow:

*/

static inline unsigned long _msecs_to_jiffies(const unsigned int m)

{

if (HZ > MSEC_PER_SEC && m > jiffies_to_msecs(MAX_JIFFY_OFFSET))

return MAX_JIFFY_OFFSET;

return (MSEC_TO_HZ_MUL32 * m + MSEC_TO_HZ_ADJ32) >> MSEC_TO_HZ_SHR32;

}

#endif

/**

* msecs_to_jiffies: - convert milliseconds to jiffies

* @m: time in milliseconds

*

* conversion is done as follows:

*

* - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET)

*

* - 'too large' values [that would result in larger than

* MAX_JIFFY_OFFSET values] mean 'infinite timeout' too.

*

* - all other values are converted to jiffies by either multiplying

* the input value by a factor or dividing it with a factor and

* handling any 32-bit overflows.

* for the details see __msecs_to_jiffies()

*

* msecs_to_jiffies() checks for the passed in value being a constant

* via __builtin_constant_p() allowing gcc to eliminate most of the

* code, __msecs_to_jiffies() is called if the value passed does not

* allow constant folding and the actual conversion must be done at

* runtime.

* the HZ range specific helpers _msecs_to_jiffies() are called both

* directly here and from __msecs_to_jiffies() in the case where

* constant folding is not possible.

*/

static __always_inline unsigned long msecs_to_jiffies(const unsigned int m)

{

if (__builtin_constant_p(m)) {

if ((int)m < 0)

return MAX_JIFFY_OFFSET;

return _msecs_to_jiffies(m);

} else {

return __msecs_to_jiffies(m);

}

}

extern unsigned long __usecs_to_jiffies(const unsigned int u);

#if !(USEC_PER_SEC % HZ)

static inline unsigned long _usecs_to_jiffies(const unsigned int u)

{

return (u + (USEC_PER_SEC / HZ) - 1) / (USEC_PER_SEC / HZ);

}

#else

static inline unsigned long _usecs_to_jiffies(const unsigned int u)

{

return (USEC_TO_HZ_MUL32 * u + USEC_TO_HZ_ADJ32)

>> USEC_TO_HZ_SHR32;

}

#endif

/**

* usecs_to_jiffies: - convert microseconds to jiffies

* @u: time in microseconds

*

* conversion is done as follows:

*

* - 'too large' values [that would result in larger than

* MAX_JIFFY_OFFSET values] mean 'infinite timeout' too.

*

* - all other values are converted to jiffies by either multiplying

* the input value by a factor or dividing it with a factor and

* handling any 32-bit overflows as for msecs_to_jiffies.

*

* usecs_to_jiffies() checks for the passed in value being a constant

* via __builtin_constant_p() allowing gcc to eliminate most of the

* code, __usecs_to_jiffies() is called if the value passed does not

* allow constant folding and the actual conversion must be done at

* runtime.

* the HZ range specific helpers _usecs_to_jiffies() are called both

* directly here and from __msecs_to_jiffies() in the case where

* constant folding is not possible.

*/

static __always_inline unsigned long usecs_to_jiffies(const unsigned int u)

{

if (__builtin_constant_p(u)) {

if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET))

return MAX_JIFFY_OFFSET;

return _usecs_to_jiffies(u);

} else {

return __usecs_to_jiffies(u);

}

}

extern unsigned long timespec64_to_jiffies(const struct timespec64 *value);

extern void jiffies_to_timespec64(const unsigned long jiffies,

struct timespec64 *value);

extern clock_t jiffies_to_clock_t(unsigned long x);

static inline clock_t jiffies_delta_to_clock_t(long delta)

{

return jiffies_to_clock_t(max(0L, delta));

}

static inline unsigned int jiffies_delta_to_msecs(long delta)

{

return jiffies_to_msecs(max(0L, delta));

}

extern unsigned long clock_t_to_jiffies(unsigned long x);

extern u64 jiffies_64_to_clock_t(u64 x);

extern u64 nsec_to_clock_t(u64 x);

extern u64 nsecs_to_jiffies64(u64 n);

extern unsigned long nsecs_to_jiffies(u64 n);

#define TIMESTAMP_SIZE 30

#endif