1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef _LINUX_JIFFIES_H |
3 | #define _LINUX_JIFFIES_H |
4 | |
5 | #include <linux/cache.h> |
6 | #include <linux/limits.h> |
7 | #include <linux/math64.h> |
8 | #include <linux/minmax.h> |
9 | #include <linux/types.h> |
10 | #include <linux/time.h> |
11 | #include <linux/timex.h> |
12 | #include <vdso/jiffies.h> |
13 | #include <asm/param.h> /* for HZ */ |
14 | #include <generated/timeconst.h> |
15 | |
16 | /* |
17 | * The following defines establish the engineering parameters of the PLL |
18 | * model. The HZ variable establishes the timer interrupt frequency, 100 Hz |
19 | * for the SunOS kernel, 256 Hz for the Ultrix kernel and 1024 Hz for the |
20 | * OSF/1 kernel. The SHIFT_HZ define expresses the same value as the |
21 | * nearest power of two in order to avoid hardware multiply operations. |
22 | */ |
23 | #if HZ >= 12 && HZ < 24 |
24 | # define SHIFT_HZ 4 |
25 | #elif HZ >= 24 && HZ < 48 |
26 | # define SHIFT_HZ 5 |
27 | #elif HZ >= 48 && HZ < 96 |
28 | # define SHIFT_HZ 6 |
29 | #elif HZ >= 96 && HZ < 192 |
30 | # define SHIFT_HZ 7 |
31 | #elif HZ >= 192 && HZ < 384 |
32 | # define SHIFT_HZ 8 |
33 | #elif HZ >= 384 && HZ < 768 |
34 | # define SHIFT_HZ 9 |
35 | #elif HZ >= 768 && HZ < 1536 |
36 | # define SHIFT_HZ 10 |
37 | #elif HZ >= 1536 && HZ < 3072 |
38 | # define SHIFT_HZ 11 |
39 | #elif HZ >= 3072 && HZ < 6144 |
40 | # define SHIFT_HZ 12 |
41 | #elif HZ >= 6144 && HZ < 12288 |
42 | # define SHIFT_HZ 13 |
43 | #else |
44 | # error Invalid value of HZ. |
45 | #endif |
46 | |
47 | /* Suppose we want to divide two numbers NOM and DEN: NOM/DEN, then we can |
48 | * improve accuracy by shifting LSH bits, hence calculating: |
49 | * (NOM << LSH) / DEN |
50 | * This however means trouble for large NOM, because (NOM << LSH) may no |
51 | * longer fit in 32 bits. The following way of calculating this gives us |
52 | * some slack, under the following conditions: |
53 | * - (NOM / DEN) fits in (32 - LSH) bits. |
54 | * - (NOM % DEN) fits in (32 - LSH) bits. |
55 | */ |
56 | #define SH_DIV(NOM,DEN,LSH) ( (((NOM) / (DEN)) << (LSH)) \ |
57 | + ((((NOM) % (DEN)) << (LSH)) + (DEN) / 2) / (DEN)) |
58 | |
59 | /* LATCH is used in the interval timer and ftape setup. */ |
60 | #define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ) /* For divider */ |
61 | |
62 | extern int register_refined_jiffies(long clock_tick_rate); |
63 | |
64 | /* TICK_USEC is the time between ticks in usec assuming SHIFTED_HZ */ |
65 | #define TICK_USEC ((USEC_PER_SEC + HZ/2) / HZ) |
66 | |
67 | /* USER_TICK_USEC is the time between ticks in usec assuming fake USER_HZ */ |
68 | #define USER_TICK_USEC ((1000000UL + USER_HZ/2) / USER_HZ) |
69 | |
70 | #ifndef __jiffy_arch_data |
71 | #define __jiffy_arch_data |
72 | #endif |
73 | |
74 | /* |
75 | * The 64-bit value is not atomic on 32-bit systems - you MUST NOT read it |
76 | * without sampling the sequence number in jiffies_lock. |
77 | * get_jiffies_64() will do this for you as appropriate. |
78 | * |
79 | * jiffies and jiffies_64 are at the same address for little-endian systems |
80 | * and for 64-bit big-endian systems. |
81 | * On 32-bit big-endian systems, jiffies is the lower 32 bits of jiffies_64 |
82 | * (i.e., at address @jiffies_64 + 4). |
83 | * See arch/ARCH/kernel/vmlinux.lds.S |
84 | */ |
85 | extern u64 __cacheline_aligned_in_smp jiffies_64; |
86 | extern unsigned long volatile __cacheline_aligned_in_smp __jiffy_arch_data jiffies; |
87 | |
88 | #if (BITS_PER_LONG < 64) |
89 | u64 get_jiffies_64(void); |
90 | #else |
91 | /** |
92 | * get_jiffies_64 - read the 64-bit non-atomic jiffies_64 value |
93 | * |
94 | * When BITS_PER_LONG < 64, this uses sequence number sampling using |
95 | * jiffies_lock to protect the 64-bit read. |
96 | * |
97 | * Return: current 64-bit jiffies value |
98 | */ |
99 | static inline u64 get_jiffies_64(void) |
100 | { |
101 | return (u64)jiffies; |
102 | } |
103 | #endif |
104 | |
105 | /* |
106 | * These inlines deal with timer wrapping correctly. You are |
107 | * strongly encouraged to use them: |
108 | * 1. Because people otherwise forget |
109 | * 2. Because if the timer wrap changes in future you won't have to |
110 | * alter your driver code. |
111 | */ |
112 | |
113 | /** |
114 | * time_after - returns true if the time a is after time b. |
115 | * @a: first comparable as unsigned long |
116 | * @b: second comparable as unsigned long |
117 | * |
118 | * Do this with "<0" and ">=0" to only test the sign of the result. A |
119 | * good compiler would generate better code (and a really good compiler |
120 | * wouldn't care). Gcc is currently neither. |
121 | * |
122 | * Return: %true is time a is after time b, otherwise %false. |
123 | */ |
124 | #define time_after(a,b) \ |
125 | (typecheck(unsigned long, a) && \ |
126 | typecheck(unsigned long, b) && \ |
127 | ((long)((b) - (a)) < 0)) |
128 | /** |
129 | * time_before - returns true if the time a is before time b. |
130 | * @a: first comparable as unsigned long |
131 | * @b: second comparable as unsigned long |
132 | * |
133 | * Return: %true is time a is before time b, otherwise %false. |
134 | */ |
135 | #define time_before(a,b) time_after(b,a) |
136 | |
137 | /** |
138 | * time_after_eq - returns true if the time a is after or the same as time b. |
139 | * @a: first comparable as unsigned long |
140 | * @b: second comparable as unsigned long |
141 | * |
142 | * Return: %true is time a is after or the same as time b, otherwise %false. |
143 | */ |
144 | #define time_after_eq(a,b) \ |
145 | (typecheck(unsigned long, a) && \ |
146 | typecheck(unsigned long, b) && \ |
147 | ((long)((a) - (b)) >= 0)) |
148 | /** |
149 | * time_before_eq - returns true if the time a is before or the same as time b. |
150 | * @a: first comparable as unsigned long |
151 | * @b: second comparable as unsigned long |
152 | * |
153 | * Return: %true is time a is before or the same as time b, otherwise %false. |
154 | */ |
155 | #define time_before_eq(a,b) time_after_eq(b,a) |
156 | |
157 | /** |
158 | * time_in_range - Calculate whether a is in the range of [b, c]. |
159 | * @a: time to test |
160 | * @b: beginning of the range |
161 | * @c: end of the range |
162 | * |
163 | * Return: %true is time a is in the range [b, c], otherwise %false. |
164 | */ |
165 | #define time_in_range(a,b,c) \ |
166 | (time_after_eq(a,b) && \ |
167 | time_before_eq(a,c)) |
168 | |
169 | /** |
170 | * time_in_range_open - Calculate whether a is in the range of [b, c). |
171 | * @a: time to test |
172 | * @b: beginning of the range |
173 | * @c: end of the range |
174 | * |
175 | * Return: %true is time a is in the range [b, c), otherwise %false. |
176 | */ |
177 | #define time_in_range_open(a,b,c) \ |
178 | (time_after_eq(a,b) && \ |
179 | time_before(a,c)) |
180 | |
181 | /* Same as above, but does so with platform independent 64bit types. |
182 | * These must be used when utilizing jiffies_64 (i.e. return value of |
183 | * get_jiffies_64()). */ |
184 | |
185 | /** |
186 | * time_after64 - returns true if the time a is after time b. |
187 | * @a: first comparable as __u64 |
188 | * @b: second comparable as __u64 |
189 | * |
190 | * This must be used when utilizing jiffies_64 (i.e. return value of |
191 | * get_jiffies_64()). |
192 | * |
193 | * Return: %true is time a is after time b, otherwise %false. |
194 | */ |
195 | #define time_after64(a,b) \ |
196 | (typecheck(__u64, a) && \ |
197 | typecheck(__u64, b) && \ |
198 | ((__s64)((b) - (a)) < 0)) |
199 | /** |
200 | * time_before64 - returns true if the time a is before time b. |
201 | * @a: first comparable as __u64 |
202 | * @b: second comparable as __u64 |
203 | * |
204 | * This must be used when utilizing jiffies_64 (i.e. return value of |
205 | * get_jiffies_64()). |
206 | * |
207 | * Return: %true is time a is before time b, otherwise %false. |
208 | */ |
209 | #define time_before64(a,b) time_after64(b,a) |
210 | |
211 | /** |
212 | * time_after_eq64 - returns true if the time a is after or the same as time b. |
213 | * @a: first comparable as __u64 |
214 | * @b: second comparable as __u64 |
215 | * |
216 | * This must be used when utilizing jiffies_64 (i.e. return value of |
217 | * get_jiffies_64()). |
218 | * |
219 | * Return: %true is time a is after or the same as time b, otherwise %false. |
220 | */ |
221 | #define time_after_eq64(a,b) \ |
222 | (typecheck(__u64, a) && \ |
223 | typecheck(__u64, b) && \ |
224 | ((__s64)((a) - (b)) >= 0)) |
225 | /** |
226 | * time_before_eq64 - returns true if the time a is before or the same as time b. |
227 | * @a: first comparable as __u64 |
228 | * @b: second comparable as __u64 |
229 | * |
230 | * This must be used when utilizing jiffies_64 (i.e. return value of |
231 | * get_jiffies_64()). |
232 | * |
233 | * Return: %true is time a is before or the same as time b, otherwise %false. |
234 | */ |
235 | #define time_before_eq64(a,b) time_after_eq64(b,a) |
236 | |
237 | /** |
238 | * time_in_range64 - Calculate whether a is in the range of [b, c]. |
239 | * @a: time to test |
240 | * @b: beginning of the range |
241 | * @c: end of the range |
242 | * |
243 | * Return: %true is time a is in the range [b, c], otherwise %false. |
244 | */ |
245 | #define time_in_range64(a, b, c) \ |
246 | (time_after_eq64(a, b) && \ |
247 | time_before_eq64(a, c)) |
248 | |
249 | /* |
250 | * These eight macros compare jiffies[_64] and 'a' for convenience. |
251 | */ |
252 | |
253 | /** |
254 | * time_is_before_jiffies - return true if a is before jiffies |
255 | * @a: time (unsigned long) to compare to jiffies |
256 | * |
257 | * Return: %true is time a is before jiffies, otherwise %false. |
258 | */ |
259 | #define time_is_before_jiffies(a) time_after(jiffies, a) |
260 | /** |
261 | * time_is_before_jiffies64 - return true if a is before jiffies_64 |
262 | * @a: time (__u64) to compare to jiffies_64 |
263 | * |
264 | * Return: %true is time a is before jiffies_64, otherwise %false. |
265 | */ |
266 | #define time_is_before_jiffies64(a) time_after64(get_jiffies_64(), a) |
267 | |
268 | /** |
269 | * time_is_after_jiffies - return true if a is after jiffies |
270 | * @a: time (unsigned long) to compare to jiffies |
271 | * |
272 | * Return: %true is time a is after jiffies, otherwise %false. |
273 | */ |
274 | #define time_is_after_jiffies(a) time_before(jiffies, a) |
275 | /** |
276 | * time_is_after_jiffies64 - return true if a is after jiffies_64 |
277 | * @a: time (__u64) to compare to jiffies_64 |
278 | * |
279 | * Return: %true is time a is after jiffies_64, otherwise %false. |
280 | */ |
281 | #define time_is_after_jiffies64(a) time_before64(get_jiffies_64(), a) |
282 | |
283 | /** |
284 | * time_is_before_eq_jiffies - return true if a is before or equal to jiffies |
285 | * @a: time (unsigned long) to compare to jiffies |
286 | * |
287 | * Return: %true is time a is before or the same as jiffies, otherwise %false. |
288 | */ |
289 | #define time_is_before_eq_jiffies(a) time_after_eq(jiffies, a) |
290 | /** |
291 | * time_is_before_eq_jiffies64 - return true if a is before or equal to jiffies_64 |
292 | * @a: time (__u64) to compare to jiffies_64 |
293 | * |
294 | * Return: %true is time a is before or the same jiffies_64, otherwise %false. |
295 | */ |
296 | #define time_is_before_eq_jiffies64(a) time_after_eq64(get_jiffies_64(), a) |
297 | |
298 | /** |
299 | * time_is_after_eq_jiffies - return true if a is after or equal to jiffies |
300 | * @a: time (unsigned long) to compare to jiffies |
301 | * |
302 | * Return: %true is time a is after or the same as jiffies, otherwise %false. |
303 | */ |
304 | #define time_is_after_eq_jiffies(a) time_before_eq(jiffies, a) |
305 | /** |
306 | * time_is_after_eq_jiffies64 - return true if a is after or equal to jiffies_64 |
307 | * @a: time (__u64) to compare to jiffies_64 |
308 | * |
309 | * Return: %true is time a is after or the same as jiffies_64, otherwise %false. |
310 | */ |
311 | #define time_is_after_eq_jiffies64(a) time_before_eq64(get_jiffies_64(), a) |
312 | |
313 | /* |
314 | * Have the 32-bit jiffies value wrap 5 minutes after boot |
315 | * so jiffies wrap bugs show up earlier. |
316 | */ |
317 | #define INITIAL_JIFFIES ((unsigned long)(unsigned int) (-300*HZ)) |
318 | |
319 | /* |
320 | * Change timeval to jiffies, trying to avoid the |
321 | * most obvious overflows.. |
322 | * |
323 | * And some not so obvious. |
324 | * |
325 | * Note that we don't want to return LONG_MAX, because |
326 | * for various timeout reasons we often end up having |
327 | * to wait "jiffies+1" in order to guarantee that we wait |
328 | * at _least_ "jiffies" - so "jiffies+1" had better still |
329 | * be positive. |
330 | */ |
331 | #define MAX_JIFFY_OFFSET ((LONG_MAX >> 1)-1) |
332 | |
333 | extern unsigned long preset_lpj; |
334 | |
335 | /* |
336 | * We want to do realistic conversions of time so we need to use the same |
337 | * values the update wall clock code uses as the jiffies size. This value |
338 | * is: TICK_NSEC (which is defined in timex.h). This |
339 | * is a constant and is in nanoseconds. We will use scaled math |
340 | * with a set of scales defined here as SEC_JIFFIE_SC, USEC_JIFFIE_SC and |
341 | * NSEC_JIFFIE_SC. Note that these defines contain nothing but |
342 | * constants and so are computed at compile time. SHIFT_HZ (computed in |
343 | * timex.h) adjusts the scaling for different HZ values. |
344 | |
345 | * Scaled math??? What is that? |
346 | * |
347 | * Scaled math is a way to do integer math on values that would, |
348 | * otherwise, either overflow, underflow, or cause undesired div |
349 | * instructions to appear in the execution path. In short, we "scale" |
350 | * up the operands so they take more bits (more precision, less |
351 | * underflow), do the desired operation and then "scale" the result back |
352 | * by the same amount. If we do the scaling by shifting we avoid the |
353 | * costly mpy and the dastardly div instructions. |
354 | |
355 | * Suppose, for example, we want to convert from seconds to jiffies |
356 | * where jiffies is defined in nanoseconds as NSEC_PER_JIFFIE. The |
357 | * simple math is: jiff = (sec * NSEC_PER_SEC) / NSEC_PER_JIFFIE; We |
358 | * observe that (NSEC_PER_SEC / NSEC_PER_JIFFIE) is a constant which we |
359 | * might calculate at compile time, however, the result will only have |
360 | * about 3-4 bits of precision (less for smaller values of HZ). |
361 | * |
362 | * So, we scale as follows: |
363 | * jiff = (sec) * (NSEC_PER_SEC / NSEC_PER_JIFFIE); |
364 | * jiff = ((sec) * ((NSEC_PER_SEC * SCALE)/ NSEC_PER_JIFFIE)) / SCALE; |
365 | * Then we make SCALE a power of two so: |
366 | * jiff = ((sec) * ((NSEC_PER_SEC << SCALE)/ NSEC_PER_JIFFIE)) >> SCALE; |
367 | * Now we define: |
368 | * #define SEC_CONV = ((NSEC_PER_SEC << SCALE)/ NSEC_PER_JIFFIE)) |
369 | * jiff = (sec * SEC_CONV) >> SCALE; |
370 | * |
371 | * Often the math we use will expand beyond 32-bits so we tell C how to |
372 | * do this and pass the 64-bit result of the mpy through the ">> SCALE" |
373 | * which should take the result back to 32-bits. We want this expansion |
374 | * to capture as much precision as possible. At the same time we don't |
375 | * want to overflow so we pick the SCALE to avoid this. In this file, |
376 | * that means using a different scale for each range of HZ values (as |
377 | * defined in timex.h). |
378 | * |
379 | * For those who want to know, gcc will give a 64-bit result from a "*" |
380 | * operator if the result is a long long AND at least one of the |
381 | * operands is cast to long long (usually just prior to the "*" so as |
382 | * not to confuse it into thinking it really has a 64-bit operand, |
383 | * which, buy the way, it can do, but it takes more code and at least 2 |
384 | * mpys). |
385 | |
386 | * We also need to be aware that one second in nanoseconds is only a |
387 | * couple of bits away from overflowing a 32-bit word, so we MUST use |
388 | * 64-bits to get the full range time in nanoseconds. |
389 | |
390 | */ |
391 | |
392 | /* |
393 | * Here are the scales we will use. One for seconds, nanoseconds and |
394 | * microseconds. |
395 | * |
396 | * Within the limits of cpp we do a rough cut at the SEC_JIFFIE_SC and |
397 | * check if the sign bit is set. If not, we bump the shift count by 1. |
398 | * (Gets an extra bit of precision where we can use it.) |
399 | * We know it is set for HZ = 1024 and HZ = 100 not for 1000. |
400 | * Haven't tested others. |
401 | |
402 | * Limits of cpp (for #if expressions) only long (no long long), but |
403 | * then we only need the most signicant bit. |
404 | */ |
405 | |
406 | #define SEC_JIFFIE_SC (31 - SHIFT_HZ) |
407 | #if !((((NSEC_PER_SEC << 2) / TICK_NSEC) << (SEC_JIFFIE_SC - 2)) & 0x80000000) |
408 | #undef SEC_JIFFIE_SC |
409 | #define SEC_JIFFIE_SC (32 - SHIFT_HZ) |
410 | #endif |
411 | #define NSEC_JIFFIE_SC (SEC_JIFFIE_SC + 29) |
412 | #define SEC_CONVERSION ((unsigned long)((((u64)NSEC_PER_SEC << SEC_JIFFIE_SC) +\ |
413 | TICK_NSEC -1) / (u64)TICK_NSEC)) |
414 | |
415 | #define NSEC_CONVERSION ((unsigned long)((((u64)1 << NSEC_JIFFIE_SC) +\ |
416 | TICK_NSEC -1) / (u64)TICK_NSEC)) |
417 | /* |
418 | * The maximum jiffie value is (MAX_INT >> 1). Here we translate that |
419 | * into seconds. The 64-bit case will overflow if we are not careful, |
420 | * so use the messy SH_DIV macro to do it. Still all constants. |
421 | */ |
422 | #if BITS_PER_LONG < 64 |
423 | # define MAX_SEC_IN_JIFFIES \ |
424 | (long)((u64)((u64)MAX_JIFFY_OFFSET * TICK_NSEC) / NSEC_PER_SEC) |
425 | #else /* take care of overflow on 64-bit machines */ |
426 | # define MAX_SEC_IN_JIFFIES \ |
427 | (SH_DIV((MAX_JIFFY_OFFSET >> SEC_JIFFIE_SC) * TICK_NSEC, NSEC_PER_SEC, 1) - 1) |
428 | |
429 | #endif |
430 | |
431 | /* |
432 | * Convert various time units to each other: |
433 | */ |
434 | extern unsigned int jiffies_to_msecs(const unsigned long j); |
435 | extern unsigned int jiffies_to_usecs(const unsigned long j); |
436 | |
437 | /** |
438 | * jiffies_to_nsecs - Convert jiffies to nanoseconds |
439 | * @j: jiffies value |
440 | * |
441 | * Return: nanoseconds value |
442 | */ |
443 | static inline u64 jiffies_to_nsecs(const unsigned long j) |
444 | { |
445 | return (u64)jiffies_to_usecs(j) * NSEC_PER_USEC; |
446 | } |
447 | |
448 | extern u64 jiffies64_to_nsecs(u64 j); |
449 | extern u64 jiffies64_to_msecs(u64 j); |
450 | |
451 | extern unsigned long __msecs_to_jiffies(const unsigned int m); |
452 | #if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ) |
453 | /* |
454 | * HZ is equal to or smaller than 1000, and 1000 is a nice round |
455 | * multiple of HZ, divide with the factor between them, but round |
456 | * upwards: |
457 | */ |
458 | static inline unsigned long _msecs_to_jiffies(const unsigned int m) |
459 | { |
460 | return (m + (MSEC_PER_SEC / HZ) - 1) / (MSEC_PER_SEC / HZ); |
461 | } |
462 | #elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC) |
463 | /* |
464 | * HZ is larger than 1000, and HZ is a nice round multiple of 1000 - |
465 | * simply multiply with the factor between them. |
466 | * |
467 | * But first make sure the multiplication result cannot overflow: |
468 | */ |
469 | static inline unsigned long _msecs_to_jiffies(const unsigned int m) |
470 | { |
471 | if (m > jiffies_to_msecs(MAX_JIFFY_OFFSET)) |
472 | return MAX_JIFFY_OFFSET; |
473 | return m * (HZ / MSEC_PER_SEC); |
474 | } |
475 | #else |
476 | /* |
477 | * Generic case - multiply, round and divide. But first check that if |
478 | * we are doing a net multiplication, that we wouldn't overflow: |
479 | */ |
480 | static inline unsigned long _msecs_to_jiffies(const unsigned int m) |
481 | { |
482 | if (HZ > MSEC_PER_SEC && m > jiffies_to_msecs(MAX_JIFFY_OFFSET)) |
483 | return MAX_JIFFY_OFFSET; |
484 | |
485 | return (MSEC_TO_HZ_MUL32 * m + MSEC_TO_HZ_ADJ32) >> MSEC_TO_HZ_SHR32; |
486 | } |
487 | #endif |
488 | /** |
489 | * msecs_to_jiffies: - convert milliseconds to jiffies |
490 | * @m: time in milliseconds |
491 | * |
492 | * conversion is done as follows: |
493 | * |
494 | * - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET) |
495 | * |
496 | * - 'too large' values [that would result in larger than |
497 | * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too. |
498 | * |
499 | * - all other values are converted to jiffies by either multiplying |
500 | * the input value by a factor or dividing it with a factor and |
501 | * handling any 32-bit overflows. |
502 | * for the details see __msecs_to_jiffies() |
503 | * |
504 | * msecs_to_jiffies() checks for the passed in value being a constant |
505 | * via __builtin_constant_p() allowing gcc to eliminate most of the |
506 | * code. __msecs_to_jiffies() is called if the value passed does not |
507 | * allow constant folding and the actual conversion must be done at |
508 | * runtime. |
509 | * The HZ range specific helpers _msecs_to_jiffies() are called both |
510 | * directly here and from __msecs_to_jiffies() in the case where |
511 | * constant folding is not possible. |
512 | * |
513 | * Return: jiffies value |
514 | */ |
515 | static __always_inline unsigned long msecs_to_jiffies(const unsigned int m) |
516 | { |
517 | if (__builtin_constant_p(m)) { |
518 | if ((int)m < 0) |
519 | return MAX_JIFFY_OFFSET; |
520 | return _msecs_to_jiffies(m); |
521 | } else { |
522 | return __msecs_to_jiffies(m); |
523 | } |
524 | } |
525 | |
526 | extern unsigned long __usecs_to_jiffies(const unsigned int u); |
527 | #if !(USEC_PER_SEC % HZ) |
528 | static inline unsigned long _usecs_to_jiffies(const unsigned int u) |
529 | { |
530 | return (u + (USEC_PER_SEC / HZ) - 1) / (USEC_PER_SEC / HZ); |
531 | } |
532 | #else |
533 | static inline unsigned long _usecs_to_jiffies(const unsigned int u) |
534 | { |
535 | return (USEC_TO_HZ_MUL32 * u + USEC_TO_HZ_ADJ32) |
536 | >> USEC_TO_HZ_SHR32; |
537 | } |
538 | #endif |
539 | |
540 | /** |
541 | * usecs_to_jiffies: - convert microseconds to jiffies |
542 | * @u: time in microseconds |
543 | * |
544 | * conversion is done as follows: |
545 | * |
546 | * - 'too large' values [that would result in larger than |
547 | * MAX_JIFFY_OFFSET values] mean 'infinite timeout' too. |
548 | * |
549 | * - all other values are converted to jiffies by either multiplying |
550 | * the input value by a factor or dividing it with a factor and |
551 | * handling any 32-bit overflows as for msecs_to_jiffies. |
552 | * |
553 | * usecs_to_jiffies() checks for the passed in value being a constant |
554 | * via __builtin_constant_p() allowing gcc to eliminate most of the |
555 | * code. __usecs_to_jiffies() is called if the value passed does not |
556 | * allow constant folding and the actual conversion must be done at |
557 | * runtime. |
558 | * The HZ range specific helpers _usecs_to_jiffies() are called both |
559 | * directly here and from __msecs_to_jiffies() in the case where |
560 | * constant folding is not possible. |
561 | * |
562 | * Return: jiffies value |
563 | */ |
564 | static __always_inline unsigned long usecs_to_jiffies(const unsigned int u) |
565 | { |
566 | if (__builtin_constant_p(u)) { |
567 | if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET)) |
568 | return MAX_JIFFY_OFFSET; |
569 | return _usecs_to_jiffies(u); |
570 | } else { |
571 | return __usecs_to_jiffies(u); |
572 | } |
573 | } |
574 | |
575 | extern unsigned long timespec64_to_jiffies(const struct timespec64 *value); |
576 | extern void jiffies_to_timespec64(const unsigned long jiffies, |
577 | struct timespec64 *value); |
578 | extern clock_t jiffies_to_clock_t(unsigned long x); |
579 | |
580 | static inline clock_t jiffies_delta_to_clock_t(long delta) |
581 | { |
582 | return jiffies_to_clock_t(max(0L, delta)); |
583 | } |
584 | |
585 | static inline unsigned int jiffies_delta_to_msecs(long delta) |
586 | { |
587 | return jiffies_to_msecs(max(0L, delta)); |
588 | } |
589 | |
590 | extern unsigned long clock_t_to_jiffies(unsigned long x); |
591 | extern u64 jiffies_64_to_clock_t(u64 x); |
592 | extern u64 nsec_to_clock_t(u64 x); |
593 | extern u64 nsecs_to_jiffies64(u64 n); |
594 | extern unsigned long nsecs_to_jiffies(u64 n); |
595 | |
596 | #define TIMESTAMP_SIZE 30 |
597 | |
598 | #endif |
599 | |