| 1 | /* |
| 2 | * Common time routines among all ppc machines. |
| 3 | * |
| 4 | * Written by Cort Dougan (cort@cs.nmt.edu) to merge |
| 5 | * Paul Mackerras' version and mine for PReP and Pmac. |
| 6 | * MPC8xx/MBX changes by Dan Malek (dmalek@jlc.net). |
| 7 | * Converted for 64-bit by Mike Corrigan (mikejc@us.ibm.com) |
| 8 | * |
| 9 | * First round of bugfixes by Gabriel Paubert (paubert@iram.es) |
| 10 | * to make clock more stable (2.4.0-test5). The only thing |
| 11 | * that this code assumes is that the timebases have been synchronized |
| 12 | * by firmware on SMP and are never stopped (never do sleep |
| 13 | * on SMP then, nap and doze are OK). |
| 14 | * |
| 15 | * Speeded up do_gettimeofday by getting rid of references to |
| 16 | * xtime (which required locks for consistency). (mikejc@us.ibm.com) |
| 17 | * |
| 18 | * TODO (not necessarily in this file): |
| 19 | * - improve precision and reproducibility of timebase frequency |
| 20 | * measurement at boot time. (for iSeries, we calibrate the timebase |
| 21 | * against the Titan chip's clock.) |
| 22 | * - for astronomical applications: add a new function to get |
| 23 | * non ambiguous timestamps even around leap seconds. This needs |
| 24 | * a new timestamp format and a good name. |
| 25 | * |
| 26 | * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 |
| 27 | * "A Kernel Model for Precision Timekeeping" by Dave Mills |
| 28 | * |
| 29 | * This program is free software; you can redistribute it and/or |
| 30 | * modify it under the terms of the GNU General Public License |
| 31 | * as published by the Free Software Foundation; either version |
| 32 | * 2 of the License, or (at your option) any later version. |
| 33 | */ |
| 34 | |
| 35 | #include <linux/errno.h> |
| 36 | #include <linux/module.h> |
| 37 | #include <linux/sched.h> |
| 38 | #include <linux/kernel.h> |
| 39 | #include <linux/param.h> |
| 40 | #include <linux/string.h> |
| 41 | #include <linux/mm.h> |
| 42 | #include <linux/interrupt.h> |
| 43 | #include <linux/timex.h> |
| 44 | #include <linux/kernel_stat.h> |
| 45 | #include <linux/time.h> |
| 46 | #include <linux/init.h> |
| 47 | #include <linux/profile.h> |
| 48 | #include <linux/cpu.h> |
| 49 | #include <linux/security.h> |
| 50 | #include <linux/percpu.h> |
| 51 | #include <linux/rtc.h> |
| 52 | #include <linux/jiffies.h> |
| 53 | #include <linux/posix-timers.h> |
| 54 | #include <linux/irq.h> |
| 55 | |
| 56 | #include <asm/io.h> |
| 57 | #include <asm/processor.h> |
| 58 | #include <asm/nvram.h> |
| 59 | #include <asm/cache.h> |
| 60 | #include <asm/machdep.h> |
| 61 | #include <asm/uaccess.h> |
| 62 | #include <asm/time.h> |
| 63 | #include <asm/prom.h> |
| 64 | #include <asm/irq.h> |
| 65 | #include <asm/div64.h> |
| 66 | #include <asm/smp.h> |
| 67 | #include <asm/vdso_datapage.h> |
| 68 | #ifdef CONFIG_PPC64 |
| 69 | #include <asm/firmware.h> |
| 70 | #endif |
| 71 | #ifdef CONFIG_PPC_ISERIES |
| 72 | #include <asm/iseries/it_lp_queue.h> |
| 73 | #include <asm/iseries/hv_call_xm.h> |
| 74 | #endif |
| 75 | #include <asm/smp.h> |
| 76 | |
| 77 | /* keep track of when we need to update the rtc */ |
| 78 | time_t last_rtc_update; |
| 79 | #ifdef CONFIG_PPC_ISERIES |
| 80 | static unsigned long __initdata iSeries_recal_titan; |
| 81 | static signed long __initdata iSeries_recal_tb; |
| 82 | #endif |
| 83 | |
| 84 | /* The decrementer counts down by 128 every 128ns on a 601. */ |
| 85 | #define DECREMENTER_COUNT_601 (1000000000 / HZ) |
| 86 | |
| 87 | #define XSEC_PER_SEC (1024*1024) |
| 88 | |
| 89 | #ifdef CONFIG_PPC64 |
| 90 | #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) |
| 91 | #else |
| 92 | /* compute ((xsec << 12) * max) >> 32 */ |
| 93 | #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) |
| 94 | #endif |
| 95 | |
| 96 | unsigned long tb_ticks_per_jiffy; |
| 97 | unsigned long tb_ticks_per_usec = 100; /* sane default */ |
| 98 | EXPORT_SYMBOL(tb_ticks_per_usec); |
| 99 | unsigned long tb_ticks_per_sec; |
| 100 | EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ |
| 101 | u64 tb_to_xs; |
| 102 | unsigned tb_to_us; |
| 103 | |
| 104 | #define TICKLEN_SCALE TICK_LENGTH_SHIFT |
| 105 | u64 last_tick_len; /* units are ns / 2^TICKLEN_SCALE */ |
| 106 | u64 ticklen_to_xs; /* 0.64 fraction */ |
| 107 | |
| 108 | /* If last_tick_len corresponds to about 1/HZ seconds, then |
| 109 | last_tick_len << TICKLEN_SHIFT will be about 2^63. */ |
| 110 | #define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ) |
| 111 | |
| 112 | DEFINE_SPINLOCK(rtc_lock); |
| 113 | EXPORT_SYMBOL_GPL(rtc_lock); |
| 114 | |
| 115 | static u64 tb_to_ns_scale __read_mostly; |
| 116 | static unsigned tb_to_ns_shift __read_mostly; |
| 117 | static unsigned long boot_tb __read_mostly; |
| 118 | |
| 119 | struct gettimeofday_struct do_gtod; |
| 120 | |
| 121 | extern struct timezone sys_tz; |
| 122 | static long timezone_offset; |
| 123 | |
| 124 | unsigned long ppc_proc_freq; |
| 125 | unsigned long ppc_tb_freq; |
| 126 | |
| 127 | static u64 tb_last_jiffy __cacheline_aligned_in_smp; |
| 128 | static DEFINE_PER_CPU(u64, last_jiffy); |
| 129 | |
| 130 | #ifdef CONFIG_VIRT_CPU_ACCOUNTING |
| 131 | /* |
| 132 | * Factors for converting from cputime_t (timebase ticks) to |
| 133 | * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds). |
| 134 | * These are all stored as 0.64 fixed-point binary fractions. |
| 135 | */ |
| 136 | u64 __cputime_jiffies_factor; |
| 137 | EXPORT_SYMBOL(__cputime_jiffies_factor); |
| 138 | u64 __cputime_msec_factor; |
| 139 | EXPORT_SYMBOL(__cputime_msec_factor); |
| 140 | u64 __cputime_sec_factor; |
| 141 | EXPORT_SYMBOL(__cputime_sec_factor); |
| 142 | u64 __cputime_clockt_factor; |
| 143 | EXPORT_SYMBOL(__cputime_clockt_factor); |
| 144 | |
| 145 | static void calc_cputime_factors(void) |
| 146 | { |
| 147 | struct div_result res; |
| 148 | |
| 149 | div128_by_32(HZ, 0, tb_ticks_per_sec, &res); |
| 150 | __cputime_jiffies_factor = res.result_low; |
| 151 | div128_by_32(1000, 0, tb_ticks_per_sec, &res); |
| 152 | __cputime_msec_factor = res.result_low; |
| 153 | div128_by_32(1, 0, tb_ticks_per_sec, &res); |
| 154 | __cputime_sec_factor = res.result_low; |
| 155 | div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res); |
| 156 | __cputime_clockt_factor = res.result_low; |
| 157 | } |
| 158 | |
| 159 | /* |
| 160 | * Read the PURR on systems that have it, otherwise the timebase. |
| 161 | */ |
| 162 | static u64 read_purr(void) |
| 163 | { |
| 164 | if (cpu_has_feature(CPU_FTR_PURR)) |
| 165 | return mfspr(SPRN_PURR); |
| 166 | return mftb(); |
| 167 | } |
| 168 | |
| 169 | /* |
| 170 | * Account time for a transition between system, hard irq |
| 171 | * or soft irq state. |
| 172 | */ |
| 173 | void account_system_vtime(struct task_struct *tsk) |
| 174 | { |
| 175 | u64 now, delta; |
| 176 | unsigned long flags; |
| 177 | |
| 178 | local_irq_save(flags); |
| 179 | now = read_purr(); |
| 180 | delta = now - get_paca()->startpurr; |
| 181 | get_paca()->startpurr = now; |
| 182 | if (!in_interrupt()) { |
| 183 | delta += get_paca()->system_time; |
| 184 | get_paca()->system_time = 0; |
| 185 | } |
| 186 | account_system_time(tsk, 0, delta); |
| 187 | local_irq_restore(flags); |
| 188 | } |
| 189 | |
| 190 | /* |
| 191 | * Transfer the user and system times accumulated in the paca |
| 192 | * by the exception entry and exit code to the generic process |
| 193 | * user and system time records. |
| 194 | * Must be called with interrupts disabled. |
| 195 | */ |
| 196 | void account_process_vtime(struct task_struct *tsk) |
| 197 | { |
| 198 | cputime_t utime; |
| 199 | |
| 200 | utime = get_paca()->user_time; |
| 201 | get_paca()->user_time = 0; |
| 202 | account_user_time(tsk, utime); |
| 203 | } |
| 204 | |
| 205 | static void account_process_time(struct pt_regs *regs) |
| 206 | { |
| 207 | int cpu = smp_processor_id(); |
| 208 | |
| 209 | account_process_vtime(current); |
| 210 | run_local_timers(); |
| 211 | if (rcu_pending(cpu)) |
| 212 | rcu_check_callbacks(cpu, user_mode(regs)); |
| 213 | scheduler_tick(); |
| 214 | run_posix_cpu_timers(current); |
| 215 | } |
| 216 | |
| 217 | /* |
| 218 | * Stuff for accounting stolen time. |
| 219 | */ |
| 220 | struct cpu_purr_data { |
| 221 | int initialized; /* thread is running */ |
| 222 | u64 tb; /* last TB value read */ |
| 223 | u64 purr; /* last PURR value read */ |
| 224 | }; |
| 225 | |
| 226 | /* |
| 227 | * Each entry in the cpu_purr_data array is manipulated only by its |
| 228 | * "owner" cpu -- usually in the timer interrupt but also occasionally |
| 229 | * in process context for cpu online. As long as cpus do not touch |
| 230 | * each others' cpu_purr_data, disabling local interrupts is |
| 231 | * sufficient to serialize accesses. |
| 232 | */ |
| 233 | static DEFINE_PER_CPU(struct cpu_purr_data, cpu_purr_data); |
| 234 | |
| 235 | static void snapshot_tb_and_purr(void *data) |
| 236 | { |
| 237 | unsigned long flags; |
| 238 | struct cpu_purr_data *p = &__get_cpu_var(cpu_purr_data); |
| 239 | |
| 240 | local_irq_save(flags); |
| 241 | p->tb = mftb(); |
| 242 | p->purr = mfspr(SPRN_PURR); |
| 243 | wmb(); |
| 244 | p->initialized = 1; |
| 245 | local_irq_restore(flags); |
| 246 | } |
| 247 | |
| 248 | /* |
| 249 | * Called during boot when all cpus have come up. |
| 250 | */ |
| 251 | void snapshot_timebases(void) |
| 252 | { |
| 253 | if (!cpu_has_feature(CPU_FTR_PURR)) |
| 254 | return; |
| 255 | on_each_cpu(snapshot_tb_and_purr, NULL, 0, 1); |
| 256 | } |
| 257 | |
| 258 | /* |
| 259 | * Must be called with interrupts disabled. |
| 260 | */ |
| 261 | void calculate_steal_time(void) |
| 262 | { |
| 263 | u64 tb, purr; |
| 264 | s64 stolen; |
| 265 | struct cpu_purr_data *pme; |
| 266 | |
| 267 | if (!cpu_has_feature(CPU_FTR_PURR)) |
| 268 | return; |
| 269 | pme = &per_cpu(cpu_purr_data, smp_processor_id()); |
| 270 | if (!pme->initialized) |
| 271 | return; /* this can happen in early boot */ |
| 272 | tb = mftb(); |
| 273 | purr = mfspr(SPRN_PURR); |
| 274 | stolen = (tb - pme->tb) - (purr - pme->purr); |
| 275 | if (stolen > 0) |
| 276 | account_steal_time(current, stolen); |
| 277 | pme->tb = tb; |
| 278 | pme->purr = purr; |
| 279 | } |
| 280 | |
| 281 | #ifdef CONFIG_PPC_SPLPAR |
| 282 | /* |
| 283 | * Must be called before the cpu is added to the online map when |
| 284 | * a cpu is being brought up at runtime. |
| 285 | */ |
| 286 | static void snapshot_purr(void) |
| 287 | { |
| 288 | struct cpu_purr_data *pme; |
| 289 | unsigned long flags; |
| 290 | |
| 291 | if (!cpu_has_feature(CPU_FTR_PURR)) |
| 292 | return; |
| 293 | local_irq_save(flags); |
| 294 | pme = &per_cpu(cpu_purr_data, smp_processor_id()); |
| 295 | pme->tb = mftb(); |
| 296 | pme->purr = mfspr(SPRN_PURR); |
| 297 | pme->initialized = 1; |
| 298 | local_irq_restore(flags); |
| 299 | } |
| 300 | |
| 301 | #endif /* CONFIG_PPC_SPLPAR */ |
| 302 | |
| 303 | #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */ |
| 304 | #define calc_cputime_factors() |
| 305 | #define account_process_time(regs) update_process_times(user_mode(regs)) |
| 306 | #define calculate_steal_time() do { } while (0) |
| 307 | #endif |
| 308 | |
| 309 | #if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR)) |
| 310 | #define snapshot_purr() do { } while (0) |
| 311 | #endif |
| 312 | |
| 313 | /* |
| 314 | * Called when a cpu comes up after the system has finished booting, |
| 315 | * i.e. as a result of a hotplug cpu action. |
| 316 | */ |
| 317 | void snapshot_timebase(void) |
| 318 | { |
| 319 | __get_cpu_var(last_jiffy) = get_tb(); |
| 320 | snapshot_purr(); |
| 321 | } |
| 322 | |
| 323 | void __delay(unsigned long loops) |
| 324 | { |
| 325 | unsigned long start; |
| 326 | int diff; |
| 327 | |
| 328 | if (__USE_RTC()) { |
| 329 | start = get_rtcl(); |
| 330 | do { |
| 331 | /* the RTCL register wraps at 1000000000 */ |
| 332 | diff = get_rtcl() - start; |
| 333 | if (diff < 0) |
| 334 | diff += 1000000000; |
| 335 | } while (diff < loops); |
| 336 | } else { |
| 337 | start = get_tbl(); |
| 338 | while (get_tbl() - start < loops) |
| 339 | HMT_low(); |
| 340 | HMT_medium(); |
| 341 | } |
| 342 | } |
| 343 | EXPORT_SYMBOL(__delay); |
| 344 | |
| 345 | void udelay(unsigned long usecs) |
| 346 | { |
| 347 | __delay(tb_ticks_per_usec * usecs); |
| 348 | } |
| 349 | EXPORT_SYMBOL(udelay); |
| 350 | |
| 351 | static __inline__ void timer_check_rtc(void) |
| 352 | { |
| 353 | /* |
| 354 | * update the rtc when needed, this should be performed on the |
| 355 | * right fraction of a second. Half or full second ? |
| 356 | * Full second works on mk48t59 clocks, others need testing. |
| 357 | * Note that this update is basically only used through |
| 358 | * the adjtimex system calls. Setting the HW clock in |
| 359 | * any other way is a /dev/rtc and userland business. |
| 360 | * This is still wrong by -0.5/+1.5 jiffies because of the |
| 361 | * timer interrupt resolution and possible delay, but here we |
| 362 | * hit a quantization limit which can only be solved by higher |
| 363 | * resolution timers and decoupling time management from timer |
| 364 | * interrupts. This is also wrong on the clocks |
| 365 | * which require being written at the half second boundary. |
| 366 | * We should have an rtc call that only sets the minutes and |
| 367 | * seconds like on Intel to avoid problems with non UTC clocks. |
| 368 | */ |
| 369 | if (ppc_md.set_rtc_time && ntp_synced() && |
| 370 | xtime.tv_sec - last_rtc_update >= 659 && |
| 371 | abs((xtime.tv_nsec/1000) - (1000000-1000000/HZ)) < 500000/HZ) { |
| 372 | struct rtc_time tm; |
| 373 | to_tm(xtime.tv_sec + 1 + timezone_offset, &tm); |
| 374 | tm.tm_year -= 1900; |
| 375 | tm.tm_mon -= 1; |
| 376 | if (ppc_md.set_rtc_time(&tm) == 0) |
| 377 | last_rtc_update = xtime.tv_sec + 1; |
| 378 | else |
| 379 | /* Try again one minute later */ |
| 380 | last_rtc_update += 60; |
| 381 | } |
| 382 | } |
| 383 | |
| 384 | /* |
| 385 | * This version of gettimeofday has microsecond resolution. |
| 386 | */ |
| 387 | static inline void __do_gettimeofday(struct timeval *tv) |
| 388 | { |
| 389 | unsigned long sec, usec; |
| 390 | u64 tb_ticks, xsec; |
| 391 | struct gettimeofday_vars *temp_varp; |
| 392 | u64 temp_tb_to_xs, temp_stamp_xsec; |
| 393 | |
| 394 | /* |
| 395 | * These calculations are faster (gets rid of divides) |
| 396 | * if done in units of 1/2^20 rather than microseconds. |
| 397 | * The conversion to microseconds at the end is done |
| 398 | * without a divide (and in fact, without a multiply) |
| 399 | */ |
| 400 | temp_varp = do_gtod.varp; |
| 401 | |
| 402 | /* Sampling the time base must be done after loading |
| 403 | * do_gtod.varp in order to avoid racing with update_gtod. |
| 404 | */ |
| 405 | data_barrier(temp_varp); |
| 406 | tb_ticks = get_tb() - temp_varp->tb_orig_stamp; |
| 407 | temp_tb_to_xs = temp_varp->tb_to_xs; |
| 408 | temp_stamp_xsec = temp_varp->stamp_xsec; |
| 409 | xsec = temp_stamp_xsec + mulhdu(tb_ticks, temp_tb_to_xs); |
| 410 | sec = xsec / XSEC_PER_SEC; |
| 411 | usec = (unsigned long)xsec & (XSEC_PER_SEC - 1); |
| 412 | usec = SCALE_XSEC(usec, 1000000); |
| 413 | |
| 414 | tv->tv_sec = sec; |
| 415 | tv->tv_usec = usec; |
| 416 | } |
| 417 | |
| 418 | void do_gettimeofday(struct timeval *tv) |
| 419 | { |
| 420 | if (__USE_RTC()) { |
| 421 | /* do this the old way */ |
| 422 | unsigned long flags, seq; |
| 423 | unsigned int sec, nsec, usec; |
| 424 | |
| 425 | do { |
| 426 | seq = read_seqbegin_irqsave(&xtime_lock, flags); |
| 427 | sec = xtime.tv_sec; |
| 428 | nsec = xtime.tv_nsec + tb_ticks_since(tb_last_jiffy); |
| 429 | } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); |
| 430 | usec = nsec / 1000; |
| 431 | while (usec >= 1000000) { |
| 432 | usec -= 1000000; |
| 433 | ++sec; |
| 434 | } |
| 435 | tv->tv_sec = sec; |
| 436 | tv->tv_usec = usec; |
| 437 | return; |
| 438 | } |
| 439 | __do_gettimeofday(tv); |
| 440 | } |
| 441 | |
| 442 | EXPORT_SYMBOL(do_gettimeofday); |
| 443 | |
| 444 | /* |
| 445 | * There are two copies of tb_to_xs and stamp_xsec so that no |
| 446 | * lock is needed to access and use these values in |
| 447 | * do_gettimeofday. We alternate the copies and as long as a |
| 448 | * reasonable time elapses between changes, there will never |
| 449 | * be inconsistent values. ntpd has a minimum of one minute |
| 450 | * between updates. |
| 451 | */ |
| 452 | static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec, |
| 453 | u64 new_tb_to_xs) |
| 454 | { |
| 455 | unsigned temp_idx; |
| 456 | struct gettimeofday_vars *temp_varp; |
| 457 | |
| 458 | temp_idx = (do_gtod.var_idx == 0); |
| 459 | temp_varp = &do_gtod.vars[temp_idx]; |
| 460 | |
| 461 | temp_varp->tb_to_xs = new_tb_to_xs; |
| 462 | temp_varp->tb_orig_stamp = new_tb_stamp; |
| 463 | temp_varp->stamp_xsec = new_stamp_xsec; |
| 464 | smp_mb(); |
| 465 | do_gtod.varp = temp_varp; |
| 466 | do_gtod.var_idx = temp_idx; |
| 467 | |
| 468 | /* |
| 469 | * tb_update_count is used to allow the userspace gettimeofday code |
| 470 | * to assure itself that it sees a consistent view of the tb_to_xs and |
| 471 | * stamp_xsec variables. It reads the tb_update_count, then reads |
| 472 | * tb_to_xs and stamp_xsec and then reads tb_update_count again. If |
| 473 | * the two values of tb_update_count match and are even then the |
| 474 | * tb_to_xs and stamp_xsec values are consistent. If not, then it |
| 475 | * loops back and reads them again until this criteria is met. |
| 476 | * We expect the caller to have done the first increment of |
| 477 | * vdso_data->tb_update_count already. |
| 478 | */ |
| 479 | vdso_data->tb_orig_stamp = new_tb_stamp; |
| 480 | vdso_data->stamp_xsec = new_stamp_xsec; |
| 481 | vdso_data->tb_to_xs = new_tb_to_xs; |
| 482 | vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec; |
| 483 | vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec; |
| 484 | smp_wmb(); |
| 485 | ++(vdso_data->tb_update_count); |
| 486 | } |
| 487 | |
| 488 | /* |
| 489 | * When the timebase - tb_orig_stamp gets too big, we do a manipulation |
| 490 | * between tb_orig_stamp and stamp_xsec. The goal here is to keep the |
| 491 | * difference tb - tb_orig_stamp small enough to always fit inside a |
| 492 | * 32 bits number. This is a requirement of our fast 32 bits userland |
| 493 | * implementation in the vdso. If we "miss" a call to this function |
| 494 | * (interrupt latency, CPU locked in a spinlock, ...) and we end up |
| 495 | * with a too big difference, then the vdso will fallback to calling |
| 496 | * the syscall |
| 497 | */ |
| 498 | static __inline__ void timer_recalc_offset(u64 cur_tb) |
| 499 | { |
| 500 | unsigned long offset; |
| 501 | u64 new_stamp_xsec; |
| 502 | u64 tlen, t2x; |
| 503 | u64 tb, xsec_old, xsec_new; |
| 504 | struct gettimeofday_vars *varp; |
| 505 | |
| 506 | if (__USE_RTC()) |
| 507 | return; |
| 508 | tlen = current_tick_length(); |
| 509 | offset = cur_tb - do_gtod.varp->tb_orig_stamp; |
| 510 | if (tlen == last_tick_len && offset < 0x80000000u) |
| 511 | return; |
| 512 | if (tlen != last_tick_len) { |
| 513 | t2x = mulhdu(tlen << TICKLEN_SHIFT, ticklen_to_xs); |
| 514 | last_tick_len = tlen; |
| 515 | } else |
| 516 | t2x = do_gtod.varp->tb_to_xs; |
| 517 | new_stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC; |
| 518 | do_div(new_stamp_xsec, 1000000000); |
| 519 | new_stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC; |
| 520 | |
| 521 | ++vdso_data->tb_update_count; |
| 522 | smp_mb(); |
| 523 | |
| 524 | /* |
| 525 | * Make sure time doesn't go backwards for userspace gettimeofday. |
| 526 | */ |
| 527 | tb = get_tb(); |
| 528 | varp = do_gtod.varp; |
| 529 | xsec_old = mulhdu(tb - varp->tb_orig_stamp, varp->tb_to_xs) |
| 530 | + varp->stamp_xsec; |
| 531 | xsec_new = mulhdu(tb - cur_tb, t2x) + new_stamp_xsec; |
| 532 | if (xsec_new < xsec_old) |
| 533 | new_stamp_xsec += xsec_old - xsec_new; |
| 534 | |
| 535 | update_gtod(cur_tb, new_stamp_xsec, t2x); |
| 536 | } |
| 537 | |
| 538 | #ifdef CONFIG_SMP |
| 539 | unsigned long profile_pc(struct pt_regs *regs) |
| 540 | { |
| 541 | unsigned long pc = instruction_pointer(regs); |
| 542 | |
| 543 | if (in_lock_functions(pc)) |
| 544 | return regs->link; |
| 545 | |
| 546 | return pc; |
| 547 | } |
| 548 | EXPORT_SYMBOL(profile_pc); |
| 549 | #endif |
| 550 | |
| 551 | #ifdef CONFIG_PPC_ISERIES |
| 552 | |
| 553 | /* |
| 554 | * This function recalibrates the timebase based on the 49-bit time-of-day |
| 555 | * value in the Titan chip. The Titan is much more accurate than the value |
| 556 | * returned by the service processor for the timebase frequency. |
| 557 | */ |
| 558 | |
| 559 | static int __init iSeries_tb_recal(void) |
| 560 | { |
| 561 | struct div_result divres; |
| 562 | unsigned long titan, tb; |
| 563 | |
| 564 | /* Make sure we only run on iSeries */ |
| 565 | if (!firmware_has_feature(FW_FEATURE_ISERIES)) |
| 566 | return -ENODEV; |
| 567 | |
| 568 | tb = get_tb(); |
| 569 | titan = HvCallXm_loadTod(); |
| 570 | if ( iSeries_recal_titan ) { |
| 571 | unsigned long tb_ticks = tb - iSeries_recal_tb; |
| 572 | unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12; |
| 573 | unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec; |
| 574 | unsigned long new_tb_ticks_per_jiffy = (new_tb_ticks_per_sec+(HZ/2))/HZ; |
| 575 | long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy; |
| 576 | char sign = '+'; |
| 577 | /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */ |
| 578 | new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ; |
| 579 | |
| 580 | if ( tick_diff < 0 ) { |
| 581 | tick_diff = -tick_diff; |
| 582 | sign = '-'; |
| 583 | } |
| 584 | if ( tick_diff ) { |
| 585 | if ( tick_diff < tb_ticks_per_jiffy/25 ) { |
| 586 | printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n", |
| 587 | new_tb_ticks_per_jiffy, sign, tick_diff ); |
| 588 | tb_ticks_per_jiffy = new_tb_ticks_per_jiffy; |
| 589 | tb_ticks_per_sec = new_tb_ticks_per_sec; |
| 590 | calc_cputime_factors(); |
| 591 | div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres ); |
| 592 | do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; |
| 593 | tb_to_xs = divres.result_low; |
| 594 | do_gtod.varp->tb_to_xs = tb_to_xs; |
| 595 | vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; |
| 596 | vdso_data->tb_to_xs = tb_to_xs; |
| 597 | } |
| 598 | else { |
| 599 | printk( "Titan recalibrate: FAILED (difference > 4 percent)\n" |
| 600 | " new tb_ticks_per_jiffy = %lu\n" |
| 601 | " old tb_ticks_per_jiffy = %lu\n", |
| 602 | new_tb_ticks_per_jiffy, tb_ticks_per_jiffy ); |
| 603 | } |
| 604 | } |
| 605 | } |
| 606 | iSeries_recal_titan = titan; |
| 607 | iSeries_recal_tb = tb; |
| 608 | |
| 609 | return 0; |
| 610 | } |
| 611 | late_initcall(iSeries_tb_recal); |
| 612 | |
| 613 | /* Called from platform early init */ |
| 614 | void __init iSeries_time_init_early(void) |
| 615 | { |
| 616 | iSeries_recal_tb = get_tb(); |
| 617 | iSeries_recal_titan = HvCallXm_loadTod(); |
| 618 | } |
| 619 | #endif /* CONFIG_PPC_ISERIES */ |
| 620 | |
| 621 | /* |
| 622 | * For iSeries shared processors, we have to let the hypervisor |
| 623 | * set the hardware decrementer. We set a virtual decrementer |
| 624 | * in the lppaca and call the hypervisor if the virtual |
| 625 | * decrementer is less than the current value in the hardware |
| 626 | * decrementer. (almost always the new decrementer value will |
| 627 | * be greater than the current hardware decementer so the hypervisor |
| 628 | * call will not be needed) |
| 629 | */ |
| 630 | |
| 631 | /* |
| 632 | * timer_interrupt - gets called when the decrementer overflows, |
| 633 | * with interrupts disabled. |
| 634 | */ |
| 635 | void timer_interrupt(struct pt_regs * regs) |
| 636 | { |
| 637 | struct pt_regs *old_regs; |
| 638 | int next_dec; |
| 639 | int cpu = smp_processor_id(); |
| 640 | unsigned long ticks; |
| 641 | u64 tb_next_jiffy; |
| 642 | |
| 643 | #ifdef CONFIG_PPC32 |
| 644 | if (atomic_read(&ppc_n_lost_interrupts) != 0) |
| 645 | do_IRQ(regs); |
| 646 | #endif |
| 647 | |
| 648 | old_regs = set_irq_regs(regs); |
| 649 | irq_enter(); |
| 650 | |
| 651 | profile_tick(CPU_PROFILING); |
| 652 | calculate_steal_time(); |
| 653 | |
| 654 | #ifdef CONFIG_PPC_ISERIES |
| 655 | if (firmware_has_feature(FW_FEATURE_ISERIES)) |
| 656 | get_lppaca()->int_dword.fields.decr_int = 0; |
| 657 | #endif |
| 658 | |
| 659 | while ((ticks = tb_ticks_since(per_cpu(last_jiffy, cpu))) |
| 660 | >= tb_ticks_per_jiffy) { |
| 661 | /* Update last_jiffy */ |
| 662 | per_cpu(last_jiffy, cpu) += tb_ticks_per_jiffy; |
| 663 | /* Handle RTCL overflow on 601 */ |
| 664 | if (__USE_RTC() && per_cpu(last_jiffy, cpu) >= 1000000000) |
| 665 | per_cpu(last_jiffy, cpu) -= 1000000000; |
| 666 | |
| 667 | /* |
| 668 | * We cannot disable the decrementer, so in the period |
| 669 | * between this cpu's being marked offline in cpu_online_map |
| 670 | * and calling stop-self, it is taking timer interrupts. |
| 671 | * Avoid calling into the scheduler rebalancing code if this |
| 672 | * is the case. |
| 673 | */ |
| 674 | if (!cpu_is_offline(cpu)) |
| 675 | account_process_time(regs); |
| 676 | |
| 677 | /* |
| 678 | * No need to check whether cpu is offline here; boot_cpuid |
| 679 | * should have been fixed up by now. |
| 680 | */ |
| 681 | if (cpu != boot_cpuid) |
| 682 | continue; |
| 683 | |
| 684 | write_seqlock(&xtime_lock); |
| 685 | tb_next_jiffy = tb_last_jiffy + tb_ticks_per_jiffy; |
| 686 | if (per_cpu(last_jiffy, cpu) >= tb_next_jiffy) { |
| 687 | tb_last_jiffy = tb_next_jiffy; |
| 688 | do_timer(1); |
| 689 | timer_recalc_offset(tb_last_jiffy); |
| 690 | timer_check_rtc(); |
| 691 | } |
| 692 | write_sequnlock(&xtime_lock); |
| 693 | } |
| 694 | |
| 695 | next_dec = tb_ticks_per_jiffy - ticks; |
| 696 | set_dec(next_dec); |
| 697 | |
| 698 | #ifdef CONFIG_PPC_ISERIES |
| 699 | if (firmware_has_feature(FW_FEATURE_ISERIES) && hvlpevent_is_pending()) |
| 700 | process_hvlpevents(); |
| 701 | #endif |
| 702 | |
| 703 | #ifdef CONFIG_PPC64 |
| 704 | /* collect purr register values often, for accurate calculations */ |
| 705 | if (firmware_has_feature(FW_FEATURE_SPLPAR)) { |
| 706 | struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); |
| 707 | cu->current_tb = mfspr(SPRN_PURR); |
| 708 | } |
| 709 | #endif |
| 710 | |
| 711 | irq_exit(); |
| 712 | set_irq_regs(old_regs); |
| 713 | } |
| 714 | |
| 715 | void wakeup_decrementer(void) |
| 716 | { |
| 717 | unsigned long ticks; |
| 718 | |
| 719 | /* |
| 720 | * The timebase gets saved on sleep and restored on wakeup, |
| 721 | * so all we need to do is to reset the decrementer. |
| 722 | */ |
| 723 | ticks = tb_ticks_since(__get_cpu_var(last_jiffy)); |
| 724 | if (ticks < tb_ticks_per_jiffy) |
| 725 | ticks = tb_ticks_per_jiffy - ticks; |
| 726 | else |
| 727 | ticks = 1; |
| 728 | set_dec(ticks); |
| 729 | } |
| 730 | |
| 731 | #ifdef CONFIG_SMP |
| 732 | void __init smp_space_timers(unsigned int max_cpus) |
| 733 | { |
| 734 | int i; |
| 735 | u64 previous_tb = per_cpu(last_jiffy, boot_cpuid); |
| 736 | |
| 737 | /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */ |
| 738 | previous_tb -= tb_ticks_per_jiffy; |
| 739 | |
| 740 | for_each_possible_cpu(i) { |
| 741 | if (i == boot_cpuid) |
| 742 | continue; |
| 743 | per_cpu(last_jiffy, i) = previous_tb; |
| 744 | } |
| 745 | } |
| 746 | #endif |
| 747 | |
| 748 | /* |
| 749 | * Scheduler clock - returns current time in nanosec units. |
| 750 | * |
| 751 | * Note: mulhdu(a, b) (multiply high double unsigned) returns |
| 752 | * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b |
| 753 | * are 64-bit unsigned numbers. |
| 754 | */ |
| 755 | unsigned long long sched_clock(void) |
| 756 | { |
| 757 | if (__USE_RTC()) |
| 758 | return get_rtc(); |
| 759 | return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; |
| 760 | } |
| 761 | |
| 762 | int do_settimeofday(struct timespec *tv) |
| 763 | { |
| 764 | time_t wtm_sec, new_sec = tv->tv_sec; |
| 765 | long wtm_nsec, new_nsec = tv->tv_nsec; |
| 766 | unsigned long flags; |
| 767 | u64 new_xsec; |
| 768 | unsigned long tb_delta; |
| 769 | |
| 770 | if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) |
| 771 | return -EINVAL; |
| 772 | |
| 773 | write_seqlock_irqsave(&xtime_lock, flags); |
| 774 | |
| 775 | /* |
| 776 | * Updating the RTC is not the job of this code. If the time is |
| 777 | * stepped under NTP, the RTC will be updated after STA_UNSYNC |
| 778 | * is cleared. Tools like clock/hwclock either copy the RTC |
| 779 | * to the system time, in which case there is no point in writing |
| 780 | * to the RTC again, or write to the RTC but then they don't call |
| 781 | * settimeofday to perform this operation. |
| 782 | */ |
| 783 | |
| 784 | /* Make userspace gettimeofday spin until we're done. */ |
| 785 | ++vdso_data->tb_update_count; |
| 786 | smp_mb(); |
| 787 | |
| 788 | /* |
| 789 | * Subtract off the number of nanoseconds since the |
| 790 | * beginning of the last tick. |
| 791 | */ |
| 792 | tb_delta = tb_ticks_since(tb_last_jiffy); |
| 793 | tb_delta = mulhdu(tb_delta, do_gtod.varp->tb_to_xs); /* in xsec */ |
| 794 | new_nsec -= SCALE_XSEC(tb_delta, 1000000000); |
| 795 | |
| 796 | wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - new_sec); |
| 797 | wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - new_nsec); |
| 798 | |
| 799 | set_normalized_timespec(&xtime, new_sec, new_nsec); |
| 800 | set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); |
| 801 | |
| 802 | /* In case of a large backwards jump in time with NTP, we want the |
| 803 | * clock to be updated as soon as the PLL is again in lock. |
| 804 | */ |
| 805 | last_rtc_update = new_sec - 658; |
| 806 | |
| 807 | ntp_clear(); |
| 808 | |
| 809 | new_xsec = xtime.tv_nsec; |
| 810 | if (new_xsec != 0) { |
| 811 | new_xsec *= XSEC_PER_SEC; |
| 812 | do_div(new_xsec, NSEC_PER_SEC); |
| 813 | } |
| 814 | new_xsec += (u64)xtime.tv_sec * XSEC_PER_SEC; |
| 815 | update_gtod(tb_last_jiffy, new_xsec, do_gtod.varp->tb_to_xs); |
| 816 | |
| 817 | vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; |
| 818 | vdso_data->tz_dsttime = sys_tz.tz_dsttime; |
| 819 | |
| 820 | write_sequnlock_irqrestore(&xtime_lock, flags); |
| 821 | clock_was_set(); |
| 822 | return 0; |
| 823 | } |
| 824 | |
| 825 | EXPORT_SYMBOL(do_settimeofday); |
| 826 | |
| 827 | static int __init get_freq(char *name, int cells, unsigned long *val) |
| 828 | { |
| 829 | struct device_node *cpu; |
| 830 | const unsigned int *fp; |
| 831 | int found = 0; |
| 832 | |
| 833 | /* The cpu node should have timebase and clock frequency properties */ |
| 834 | cpu = of_find_node_by_type(NULL, "cpu"); |
| 835 | |
| 836 | if (cpu) { |
| 837 | fp = of_get_property(cpu, name, NULL); |
| 838 | if (fp) { |
| 839 | found = 1; |
| 840 | *val = of_read_ulong(fp, cells); |
| 841 | } |
| 842 | |
| 843 | of_node_put(cpu); |
| 844 | } |
| 845 | |
| 846 | return found; |
| 847 | } |
| 848 | |
| 849 | void __init generic_calibrate_decr(void) |
| 850 | { |
| 851 | ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ |
| 852 | |
| 853 | if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && |
| 854 | !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { |
| 855 | |
| 856 | printk(KERN_ERR "WARNING: Estimating decrementer frequency " |
| 857 | "(not found)\n"); |
| 858 | } |
| 859 | |
| 860 | ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ |
| 861 | |
| 862 | if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && |
| 863 | !get_freq("clock-frequency", 1, &ppc_proc_freq)) { |
| 864 | |
| 865 | printk(KERN_ERR "WARNING: Estimating processor frequency " |
| 866 | "(not found)\n"); |
| 867 | } |
| 868 | |
| 869 | #ifdef CONFIG_BOOKE |
| 870 | /* Set the time base to zero */ |
| 871 | mtspr(SPRN_TBWL, 0); |
| 872 | mtspr(SPRN_TBWU, 0); |
| 873 | |
| 874 | /* Clear any pending timer interrupts */ |
| 875 | mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); |
| 876 | |
| 877 | /* Enable decrementer interrupt */ |
| 878 | mtspr(SPRN_TCR, TCR_DIE); |
| 879 | #endif |
| 880 | } |
| 881 | |
| 882 | unsigned long get_boot_time(void) |
| 883 | { |
| 884 | struct rtc_time tm; |
| 885 | |
| 886 | if (ppc_md.get_boot_time) |
| 887 | return ppc_md.get_boot_time(); |
| 888 | if (!ppc_md.get_rtc_time) |
| 889 | return 0; |
| 890 | ppc_md.get_rtc_time(&tm); |
| 891 | return mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, |
| 892 | tm.tm_hour, tm.tm_min, tm.tm_sec); |
| 893 | } |
| 894 | |
| 895 | /* This function is only called on the boot processor */ |
| 896 | void __init time_init(void) |
| 897 | { |
| 898 | unsigned long flags; |
| 899 | unsigned long tm = 0; |
| 900 | struct div_result res; |
| 901 | u64 scale, x; |
| 902 | unsigned shift; |
| 903 | |
| 904 | if (ppc_md.time_init != NULL) |
| 905 | timezone_offset = ppc_md.time_init(); |
| 906 | |
| 907 | if (__USE_RTC()) { |
| 908 | /* 601 processor: dec counts down by 128 every 128ns */ |
| 909 | ppc_tb_freq = 1000000000; |
| 910 | tb_last_jiffy = get_rtcl(); |
| 911 | } else { |
| 912 | /* Normal PowerPC with timebase register */ |
| 913 | ppc_md.calibrate_decr(); |
| 914 | printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", |
| 915 | ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); |
| 916 | printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", |
| 917 | ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); |
| 918 | tb_last_jiffy = get_tb(); |
| 919 | } |
| 920 | |
| 921 | tb_ticks_per_jiffy = ppc_tb_freq / HZ; |
| 922 | tb_ticks_per_sec = ppc_tb_freq; |
| 923 | tb_ticks_per_usec = ppc_tb_freq / 1000000; |
| 924 | tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000); |
| 925 | calc_cputime_factors(); |
| 926 | |
| 927 | /* |
| 928 | * Calculate the length of each tick in ns. It will not be |
| 929 | * exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ. |
| 930 | * We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq, |
| 931 | * rounded up. |
| 932 | */ |
| 933 | x = (u64) NSEC_PER_SEC * tb_ticks_per_jiffy + ppc_tb_freq - 1; |
| 934 | do_div(x, ppc_tb_freq); |
| 935 | tick_nsec = x; |
| 936 | last_tick_len = x << TICKLEN_SCALE; |
| 937 | |
| 938 | /* |
| 939 | * Compute ticklen_to_xs, which is a factor which gets multiplied |
| 940 | * by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value. |
| 941 | * It is computed as: |
| 942 | * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9) |
| 943 | * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT |
| 944 | * which turns out to be N = 51 - SHIFT_HZ. |
| 945 | * This gives the result as a 0.64 fixed-point fraction. |
| 946 | * That value is reduced by an offset amounting to 1 xsec per |
| 947 | * 2^31 timebase ticks to avoid problems with time going backwards |
| 948 | * by 1 xsec when we do timer_recalc_offset due to losing the |
| 949 | * fractional xsec. That offset is equal to ppc_tb_freq/2^51 |
| 950 | * since there are 2^20 xsec in a second. |
| 951 | */ |
| 952 | div128_by_32((1ULL << 51) - ppc_tb_freq, 0, |
| 953 | tb_ticks_per_jiffy << SHIFT_HZ, &res); |
| 954 | div128_by_32(res.result_high, res.result_low, NSEC_PER_SEC, &res); |
| 955 | ticklen_to_xs = res.result_low; |
| 956 | |
| 957 | /* Compute tb_to_xs from tick_nsec */ |
| 958 | tb_to_xs = mulhdu(last_tick_len << TICKLEN_SHIFT, ticklen_to_xs); |
| 959 | |
| 960 | /* |
| 961 | * Compute scale factor for sched_clock. |
| 962 | * The calibrate_decr() function has set tb_ticks_per_sec, |
| 963 | * which is the timebase frequency. |
| 964 | * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret |
| 965 | * the 128-bit result as a 64.64 fixed-point number. |
| 966 | * We then shift that number right until it is less than 1.0, |
| 967 | * giving us the scale factor and shift count to use in |
| 968 | * sched_clock(). |
| 969 | */ |
| 970 | div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); |
| 971 | scale = res.result_low; |
| 972 | for (shift = 0; res.result_high != 0; ++shift) { |
| 973 | scale = (scale >> 1) | (res.result_high << 63); |
| 974 | res.result_high >>= 1; |
| 975 | } |
| 976 | tb_to_ns_scale = scale; |
| 977 | tb_to_ns_shift = shift; |
| 978 | /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ |
| 979 | boot_tb = get_tb(); |
| 980 | |
| 981 | tm = get_boot_time(); |
| 982 | |
| 983 | write_seqlock_irqsave(&xtime_lock, flags); |
| 984 | |
| 985 | /* If platform provided a timezone (pmac), we correct the time */ |
| 986 | if (timezone_offset) { |
| 987 | sys_tz.tz_minuteswest = -timezone_offset / 60; |
| 988 | sys_tz.tz_dsttime = 0; |
| 989 | tm -= timezone_offset; |
| 990 | } |
| 991 | |
| 992 | xtime.tv_sec = tm; |
| 993 | xtime.tv_nsec = 0; |
| 994 | do_gtod.varp = &do_gtod.vars[0]; |
| 995 | do_gtod.var_idx = 0; |
| 996 | do_gtod.varp->tb_orig_stamp = tb_last_jiffy; |
| 997 | __get_cpu_var(last_jiffy) = tb_last_jiffy; |
| 998 | do_gtod.varp->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC; |
| 999 | do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; |
| 1000 | do_gtod.varp->tb_to_xs = tb_to_xs; |
| 1001 | do_gtod.tb_to_us = tb_to_us; |
| 1002 | |
| 1003 | vdso_data->tb_orig_stamp = tb_last_jiffy; |
| 1004 | vdso_data->tb_update_count = 0; |
| 1005 | vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; |
| 1006 | vdso_data->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC; |
| 1007 | vdso_data->tb_to_xs = tb_to_xs; |
| 1008 | |
| 1009 | time_freq = 0; |
| 1010 | |
| 1011 | last_rtc_update = xtime.tv_sec; |
| 1012 | set_normalized_timespec(&wall_to_monotonic, |
| 1013 | -xtime.tv_sec, -xtime.tv_nsec); |
| 1014 | write_sequnlock_irqrestore(&xtime_lock, flags); |
| 1015 | |
| 1016 | /* Not exact, but the timer interrupt takes care of this */ |
| 1017 | set_dec(tb_ticks_per_jiffy); |
| 1018 | } |
| 1019 | |
| 1020 | |
| 1021 | #define FEBRUARY 2 |
| 1022 | #define STARTOFTIME 1970 |
| 1023 | #define SECDAY 86400L |
| 1024 | #define SECYR (SECDAY * 365) |
| 1025 | #define leapyear(year) ((year) % 4 == 0 && \ |
| 1026 | ((year) % 100 != 0 || (year) % 400 == 0)) |
| 1027 | #define days_in_year(a) (leapyear(a) ? 366 : 365) |
| 1028 | #define days_in_month(a) (month_days[(a) - 1]) |
| 1029 | |
| 1030 | static int month_days[12] = { |
| 1031 | 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 |
| 1032 | }; |
| 1033 | |
| 1034 | /* |
| 1035 | * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) |
| 1036 | */ |
| 1037 | void GregorianDay(struct rtc_time * tm) |
| 1038 | { |
| 1039 | int leapsToDate; |
| 1040 | int lastYear; |
| 1041 | int day; |
| 1042 | int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; |
| 1043 | |
| 1044 | lastYear = tm->tm_year - 1; |
| 1045 | |
| 1046 | /* |
| 1047 | * Number of leap corrections to apply up to end of last year |
| 1048 | */ |
| 1049 | leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400; |
| 1050 | |
| 1051 | /* |
| 1052 | * This year is a leap year if it is divisible by 4 except when it is |
| 1053 | * divisible by 100 unless it is divisible by 400 |
| 1054 | * |
| 1055 | * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was |
| 1056 | */ |
| 1057 | day = tm->tm_mon > 2 && leapyear(tm->tm_year); |
| 1058 | |
| 1059 | day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + |
| 1060 | tm->tm_mday; |
| 1061 | |
| 1062 | tm->tm_wday = day % 7; |
| 1063 | } |
| 1064 | |
| 1065 | void to_tm(int tim, struct rtc_time * tm) |
| 1066 | { |
| 1067 | register int i; |
| 1068 | register long hms, day; |
| 1069 | |
| 1070 | day = tim / SECDAY; |
| 1071 | hms = tim % SECDAY; |
| 1072 | |
| 1073 | /* Hours, minutes, seconds are easy */ |
| 1074 | tm->tm_hour = hms / 3600; |
| 1075 | tm->tm_min = (hms % 3600) / 60; |
| 1076 | tm->tm_sec = (hms % 3600) % 60; |
| 1077 | |
| 1078 | /* Number of years in days */ |
| 1079 | for (i = STARTOFTIME; day >= days_in_year(i); i++) |
| 1080 | day -= days_in_year(i); |
| 1081 | tm->tm_year = i; |
| 1082 | |
| 1083 | /* Number of months in days left */ |
| 1084 | if (leapyear(tm->tm_year)) |
| 1085 | days_in_month(FEBRUARY) = 29; |
| 1086 | for (i = 1; day >= days_in_month(i); i++) |
| 1087 | day -= days_in_month(i); |
| 1088 | days_in_month(FEBRUARY) = 28; |
| 1089 | tm->tm_mon = i; |
| 1090 | |
| 1091 | /* Days are what is left over (+1) from all that. */ |
| 1092 | tm->tm_mday = day + 1; |
| 1093 | |
| 1094 | /* |
| 1095 | * Determine the day of week |
| 1096 | */ |
| 1097 | GregorianDay(tm); |
| 1098 | } |
| 1099 | |
| 1100 | /* Auxiliary function to compute scaling factors */ |
| 1101 | /* Actually the choice of a timebase running at 1/4 the of the bus |
| 1102 | * frequency giving resolution of a few tens of nanoseconds is quite nice. |
| 1103 | * It makes this computation very precise (27-28 bits typically) which |
| 1104 | * is optimistic considering the stability of most processor clock |
| 1105 | * oscillators and the precision with which the timebase frequency |
| 1106 | * is measured but does not harm. |
| 1107 | */ |
| 1108 | unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale) |
| 1109 | { |
| 1110 | unsigned mlt=0, tmp, err; |
| 1111 | /* No concern for performance, it's done once: use a stupid |
| 1112 | * but safe and compact method to find the multiplier. |
| 1113 | */ |
| 1114 | |
| 1115 | for (tmp = 1U<<31; tmp != 0; tmp >>= 1) { |
| 1116 | if (mulhwu(inscale, mlt|tmp) < outscale) |
| 1117 | mlt |= tmp; |
| 1118 | } |
| 1119 | |
| 1120 | /* We might still be off by 1 for the best approximation. |
| 1121 | * A side effect of this is that if outscale is too large |
| 1122 | * the returned value will be zero. |
| 1123 | * Many corner cases have been checked and seem to work, |
| 1124 | * some might have been forgotten in the test however. |
| 1125 | */ |
| 1126 | |
| 1127 | err = inscale * (mlt+1); |
| 1128 | if (err <= inscale/2) |
| 1129 | mlt++; |
| 1130 | return mlt; |
| 1131 | } |
| 1132 | |
| 1133 | /* |
| 1134 | * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit |
| 1135 | * result. |
| 1136 | */ |
| 1137 | void div128_by_32(u64 dividend_high, u64 dividend_low, |
| 1138 | unsigned divisor, struct div_result *dr) |
| 1139 | { |
| 1140 | unsigned long a, b, c, d; |
| 1141 | unsigned long w, x, y, z; |
| 1142 | u64 ra, rb, rc; |
| 1143 | |
| 1144 | a = dividend_high >> 32; |
| 1145 | b = dividend_high & 0xffffffff; |
| 1146 | c = dividend_low >> 32; |
| 1147 | d = dividend_low & 0xffffffff; |
| 1148 | |
| 1149 | w = a / divisor; |
| 1150 | ra = ((u64)(a - (w * divisor)) << 32) + b; |
| 1151 | |
| 1152 | rb = ((u64) do_div(ra, divisor) << 32) + c; |
| 1153 | x = ra; |
| 1154 | |
| 1155 | rc = ((u64) do_div(rb, divisor) << 32) + d; |
| 1156 | y = rb; |
| 1157 | |
| 1158 | do_div(rc, divisor); |
| 1159 | z = rc; |
| 1160 | |
| 1161 | dr->result_high = ((u64)w << 32) + x; |
| 1162 | dr->result_low = ((u64)y << 32) + z; |
| 1163 | |
| 1164 | } |