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 |