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  */
ktime_set(const s64 secs,const unsigned long nsecs)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: */
timespec_to_ktime(struct timespec ts)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: */
timespec64_to_ktime(struct timespec64 ts)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: */
timeval_to_ktime(struct timeval tv)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 */
ktime_to_ns(const ktime_t kt)97 static inline s64 ktime_to_ns(const ktime_t kt)
98 {
99 	return kt;
100 }
101 
102 /**
103  * ktime_compare - Compares two ktime_t variables for less, greater or equal
104  * @cmp1:	comparable1
105  * @cmp2:	comparable2
106  *
107  * Return: ...
108  *   cmp1  < cmp2: return <0
109  *   cmp1 == cmp2: return 0
110  *   cmp1  > cmp2: return >0
111  */
ktime_compare(const ktime_t cmp1,const ktime_t cmp2)112 static inline int ktime_compare(const ktime_t cmp1, const ktime_t cmp2)
113 {
114 	if (cmp1 < cmp2)
115 		return -1;
116 	if (cmp1 > cmp2)
117 		return 1;
118 	return 0;
119 }
120 
121 /**
122  * ktime_after - Compare if a ktime_t value is bigger than another one.
123  * @cmp1:	comparable1
124  * @cmp2:	comparable2
125  *
126  * Return: true if cmp1 happened after cmp2.
127  */
ktime_after(const ktime_t cmp1,const ktime_t cmp2)128 static inline bool ktime_after(const ktime_t cmp1, const ktime_t cmp2)
129 {
130 	return ktime_compare(cmp1, cmp2) > 0;
131 }
132 
133 /**
134  * ktime_before - Compare if a ktime_t value is smaller than another one.
135  * @cmp1:	comparable1
136  * @cmp2:	comparable2
137  *
138  * Return: true if cmp1 happened before cmp2.
139  */
ktime_before(const ktime_t cmp1,const ktime_t cmp2)140 static inline bool ktime_before(const ktime_t cmp1, const ktime_t cmp2)
141 {
142 	return ktime_compare(cmp1, cmp2) < 0;
143 }
144 
145 #if BITS_PER_LONG < 64
146 extern s64 __ktime_divns(const ktime_t kt, s64 div);
ktime_divns(const ktime_t kt,s64 div)147 static inline s64 ktime_divns(const ktime_t kt, s64 div)
148 {
149 	/*
150 	 * Negative divisors could cause an inf loop,
151 	 * so bug out here.
152 	 */
153 	BUG_ON(div < 0);
154 	if (__builtin_constant_p(div) && !(div >> 32)) {
155 		s64 ns = kt;
156 		u64 tmp = ns < 0 ? -ns : ns;
157 
158 		do_div(tmp, div);
159 		return ns < 0 ? -tmp : tmp;
160 	} else {
161 		return __ktime_divns(kt, div);
162 	}
163 }
164 #else /* BITS_PER_LONG < 64 */
ktime_divns(const ktime_t kt,s64 div)165 static inline s64 ktime_divns(const ktime_t kt, s64 div)
166 {
167 	/*
168 	 * 32-bit implementation cannot handle negative divisors,
169 	 * so catch them on 64bit as well.
170 	 */
171 	WARN_ON(div < 0);
172 	return kt / div;
173 }
174 #endif
175 
ktime_to_us(const ktime_t kt)176 static inline s64 ktime_to_us(const ktime_t kt)
177 {
178 	return ktime_divns(kt, NSEC_PER_USEC);
179 }
180 
ktime_to_ms(const ktime_t kt)181 static inline s64 ktime_to_ms(const ktime_t kt)
182 {
183 	return ktime_divns(kt, NSEC_PER_MSEC);
184 }
185 
ktime_us_delta(const ktime_t later,const ktime_t earlier)186 static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)
187 {
188        return ktime_to_us(ktime_sub(later, earlier));
189 }
190 
ktime_ms_delta(const ktime_t later,const ktime_t earlier)191 static inline s64 ktime_ms_delta(const ktime_t later, const ktime_t earlier)
192 {
193 	return ktime_to_ms(ktime_sub(later, earlier));
194 }
195 
ktime_add_us(const ktime_t kt,const u64 usec)196 static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec)
197 {
198 	return ktime_add_ns(kt, usec * NSEC_PER_USEC);
199 }
200 
ktime_add_ms(const ktime_t kt,const u64 msec)201 static inline ktime_t ktime_add_ms(const ktime_t kt, const u64 msec)
202 {
203 	return ktime_add_ns(kt, msec * NSEC_PER_MSEC);
204 }
205 
ktime_sub_us(const ktime_t kt,const u64 usec)206 static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
207 {
208 	return ktime_sub_ns(kt, usec * NSEC_PER_USEC);
209 }
210 
ktime_sub_ms(const ktime_t kt,const u64 msec)211 static inline ktime_t ktime_sub_ms(const ktime_t kt, const u64 msec)
212 {
213 	return ktime_sub_ns(kt, msec * NSEC_PER_MSEC);
214 }
215 
216 extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);
217 
218 /**
219  * ktime_to_timespec_cond - convert a ktime_t variable to timespec
220  *			    format only if the variable contains data
221  * @kt:		the ktime_t variable to convert
222  * @ts:		the timespec variable to store the result in
223  *
224  * Return: %true if there was a successful conversion, %false if kt was 0.
225  */
ktime_to_timespec_cond(const ktime_t kt,struct timespec * ts)226 static inline __must_check bool ktime_to_timespec_cond(const ktime_t kt,
227 						       struct timespec *ts)
228 {
229 	if (kt) {
230 		*ts = ktime_to_timespec(kt);
231 		return true;
232 	} else {
233 		return false;
234 	}
235 }
236 
237 /**
238  * ktime_to_timespec64_cond - convert a ktime_t variable to timespec64
239  *			    format only if the variable contains data
240  * @kt:		the ktime_t variable to convert
241  * @ts:		the timespec variable to store the result in
242  *
243  * Return: %true if there was a successful conversion, %false if kt was 0.
244  */
ktime_to_timespec64_cond(const ktime_t kt,struct timespec64 * ts)245 static inline __must_check bool ktime_to_timespec64_cond(const ktime_t kt,
246 						       struct timespec64 *ts)
247 {
248 	if (kt) {
249 		*ts = ktime_to_timespec64(kt);
250 		return true;
251 	} else {
252 		return false;
253 	}
254 }
255 
256 /*
257  * The resolution of the clocks. The resolution value is returned in
258  * the clock_getres() system call to give application programmers an
259  * idea of the (in)accuracy of timers. Timer values are rounded up to
260  * this resolution values.
261  */
262 #define LOW_RES_NSEC		TICK_NSEC
263 #define KTIME_LOW_RES		(LOW_RES_NSEC)
264 
ns_to_ktime(u64 ns)265 static inline ktime_t ns_to_ktime(u64 ns)
266 {
267 	return ns;
268 }
269 
ms_to_ktime(u64 ms)270 static inline ktime_t ms_to_ktime(u64 ms)
271 {
272 	return ms * NSEC_PER_MSEC;
273 }
274 
275 # include <linux/timekeeping.h>
276 # include <linux/timekeeping32.h>
277 
278 #endif
279