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/*
28 * ktime_t:
29 *
30 * A single 64-bit variable is used to store the hrtimers
31 * internal representation of time values in scalar nanoseconds. The
32 * design plays out best on 64-bit CPUs, where most conversions are
33 * NOPs and most arithmetic ktime_t operations are plain arithmetic
34 * operations.
35 *
36 */
37union ktime {
38	s64	tv64;
39};
40
41typedef union ktime ktime_t;		/* Kill this */
42
43/**
44 * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value
45 * @secs:	seconds to set
46 * @nsecs:	nanoseconds to set
47 *
48 * Return: The ktime_t representation of the value.
49 */
50static inline ktime_t ktime_set(const s64 secs, const unsigned long nsecs)
51{
52	if (unlikely(secs >= KTIME_SEC_MAX))
53		return (ktime_t){ .tv64 = KTIME_MAX };
54
55	return (ktime_t) { .tv64 = secs * NSEC_PER_SEC + (s64)nsecs };
56}
57
58/* Subtract two ktime_t variables. rem = lhs -rhs: */
59#define ktime_sub(lhs, rhs) \
60		({ (ktime_t){ .tv64 = (lhs).tv64 - (rhs).tv64 }; })
61
62/* Add two ktime_t variables. res = lhs + rhs: */
63#define ktime_add(lhs, rhs) \
64		({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; })
65
66/*
67 * Add a ktime_t variable and a scalar nanosecond value.
68 * res = kt + nsval:
69 */
70#define ktime_add_ns(kt, nsval) \
71		({ (ktime_t){ .tv64 = (kt).tv64 + (nsval) }; })
72
73/*
74 * Subtract a scalar nanosecod from a ktime_t variable
75 * res = kt - nsval:
76 */
77#define ktime_sub_ns(kt, nsval) \
78		({ (ktime_t){ .tv64 = (kt).tv64 - (nsval) }; })
79
80/* convert a timespec to ktime_t format: */
81static inline ktime_t timespec_to_ktime(struct timespec ts)
82{
83	return ktime_set(ts.tv_sec, ts.tv_nsec);
84}
85
86/* convert a timespec64 to ktime_t format: */
87static inline ktime_t timespec64_to_ktime(struct timespec64 ts)
88{
89	return ktime_set(ts.tv_sec, ts.tv_nsec);
90}
91
92/* convert a timeval to ktime_t format: */
93static inline ktime_t timeval_to_ktime(struct timeval tv)
94{
95	return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
96}
97
98/* Map the ktime_t to timespec conversion to ns_to_timespec function */
99#define ktime_to_timespec(kt)		ns_to_timespec((kt).tv64)
100
101/* Map the ktime_t to timespec conversion to ns_to_timespec function */
102#define ktime_to_timespec64(kt)		ns_to_timespec64((kt).tv64)
103
104/* Map the ktime_t to timeval conversion to ns_to_timeval function */
105#define ktime_to_timeval(kt)		ns_to_timeval((kt).tv64)
106
107/* Convert ktime_t to nanoseconds - NOP in the scalar storage format: */
108#define ktime_to_ns(kt)			((kt).tv64)
109
110
111/**
112 * ktime_equal - Compares two ktime_t variables to see if they are equal
113 * @cmp1:	comparable1
114 * @cmp2:	comparable2
115 *
116 * Compare two ktime_t variables.
117 *
118 * Return: 1 if equal.
119 */
120static inline int ktime_equal(const ktime_t cmp1, const ktime_t cmp2)
121{
122	return cmp1.tv64 == cmp2.tv64;
123}
124
125/**
126 * ktime_compare - Compares two ktime_t variables for less, greater or equal
127 * @cmp1:	comparable1
128 * @cmp2:	comparable2
129 *
130 * Return: ...
131 *   cmp1  < cmp2: return <0
132 *   cmp1 == cmp2: return 0
133 *   cmp1  > cmp2: return >0
134 */
135static inline int ktime_compare(const ktime_t cmp1, const ktime_t cmp2)
136{
137	if (cmp1.tv64 < cmp2.tv64)
138		return -1;
139	if (cmp1.tv64 > cmp2.tv64)
140		return 1;
141	return 0;
142}
143
144/**
145 * ktime_after - Compare if a ktime_t value is bigger than another one.
146 * @cmp1:	comparable1
147 * @cmp2:	comparable2
148 *
149 * Return: true if cmp1 happened after cmp2.
150 */
151static inline bool ktime_after(const ktime_t cmp1, const ktime_t cmp2)
152{
153	return ktime_compare(cmp1, cmp2) > 0;
154}
155
156/**
157 * ktime_before - Compare if a ktime_t value is smaller than another one.
158 * @cmp1:	comparable1
159 * @cmp2:	comparable2
160 *
161 * Return: true if cmp1 happened before cmp2.
162 */
163static inline bool ktime_before(const ktime_t cmp1, const ktime_t cmp2)
164{
165	return ktime_compare(cmp1, cmp2) < 0;
166}
167
168#if BITS_PER_LONG < 64
169extern s64 __ktime_divns(const ktime_t kt, s64 div);
170static inline s64 ktime_divns(const ktime_t kt, s64 div)
171{
172	/*
173	 * Negative divisors could cause an inf loop,
174	 * so bug out here.
175	 */
176	BUG_ON(div < 0);
177	if (__builtin_constant_p(div) && !(div >> 32)) {
178		s64 ns = kt.tv64;
179		u64 tmp = ns < 0 ? -ns : ns;
180
181		do_div(tmp, div);
182		return ns < 0 ? -tmp : tmp;
183	} else {
184		return __ktime_divns(kt, div);
185	}
186}
187#else /* BITS_PER_LONG < 64 */
188static inline s64 ktime_divns(const ktime_t kt, s64 div)
189{
190	/*
191	 * 32-bit implementation cannot handle negative divisors,
192	 * so catch them on 64bit as well.
193	 */
194	WARN_ON(div < 0);
195	return kt.tv64 / div;
196}
197#endif
198
199static inline s64 ktime_to_us(const ktime_t kt)
200{
201	return ktime_divns(kt, NSEC_PER_USEC);
202}
203
204static inline s64 ktime_to_ms(const ktime_t kt)
205{
206	return ktime_divns(kt, NSEC_PER_MSEC);
207}
208
209static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)
210{
211       return ktime_to_us(ktime_sub(later, earlier));
212}
213
214static inline s64 ktime_ms_delta(const ktime_t later, const ktime_t earlier)
215{
216	return ktime_to_ms(ktime_sub(later, earlier));
217}
218
219static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec)
220{
221	return ktime_add_ns(kt, usec * NSEC_PER_USEC);
222}
223
224static inline ktime_t ktime_add_ms(const ktime_t kt, const u64 msec)
225{
226	return ktime_add_ns(kt, msec * NSEC_PER_MSEC);
227}
228
229static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
230{
231	return ktime_sub_ns(kt, usec * NSEC_PER_USEC);
232}
233
234extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);
235
236/**
237 * ktime_to_timespec_cond - convert a ktime_t variable to timespec
238 *			    format only if the variable contains data
239 * @kt:		the ktime_t variable to convert
240 * @ts:		the timespec variable to store the result in
241 *
242 * Return: %true if there was a successful conversion, %false if kt was 0.
243 */
244static inline __must_check bool ktime_to_timespec_cond(const ktime_t kt,
245						       struct timespec *ts)
246{
247	if (kt.tv64) {
248		*ts = ktime_to_timespec(kt);
249		return true;
250	} else {
251		return false;
252	}
253}
254
255/**
256 * ktime_to_timespec64_cond - convert a ktime_t variable to timespec64
257 *			    format only if the variable contains data
258 * @kt:		the ktime_t variable to convert
259 * @ts:		the timespec variable to store the result in
260 *
261 * Return: %true if there was a successful conversion, %false if kt was 0.
262 */
263static inline __must_check bool ktime_to_timespec64_cond(const ktime_t kt,
264						       struct timespec64 *ts)
265{
266	if (kt.tv64) {
267		*ts = ktime_to_timespec64(kt);
268		return true;
269	} else {
270		return false;
271	}
272}
273
274/*
275 * The resolution of the clocks. The resolution value is returned in
276 * the clock_getres() system call to give application programmers an
277 * idea of the (in)accuracy of timers. Timer values are rounded up to
278 * this resolution values.
279 */
280#define LOW_RES_NSEC		TICK_NSEC
281#define KTIME_LOW_RES		(ktime_t){ .tv64 = LOW_RES_NSEC }
282
283static inline ktime_t ns_to_ktime(u64 ns)
284{
285	static const ktime_t ktime_zero = { .tv64 = 0 };
286
287	return ktime_add_ns(ktime_zero, ns);
288}
289
290static inline ktime_t ms_to_ktime(u64 ms)
291{
292	static const ktime_t ktime_zero = { .tv64 = 0 };
293
294	return ktime_add_ms(ktime_zero, ms);
295}
296
297# include <linux/timekeeping.h>
298
299#endif
300