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. 21 * - for astronomical applications: add a new function to get 22 * non ambiguous timestamps even around leap seconds. This needs 23 * a new timestamp format and a good name. 24 * 25 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 26 * "A Kernel Model for Precision Timekeeping" by Dave Mills 27 * 28 * This program is free software; you can redistribute it and/or 29 * modify it under the terms of the GNU General Public License 30 * as published by the Free Software Foundation; either version 31 * 2 of the License, or (at your option) any later version. 32 */ 33 34 #include <linux/errno.h> 35 #include <linux/export.h> 36 #include <linux/sched.h> 37 #include <linux/kernel.h> 38 #include <linux/param.h> 39 #include <linux/string.h> 40 #include <linux/mm.h> 41 #include <linux/interrupt.h> 42 #include <linux/timex.h> 43 #include <linux/kernel_stat.h> 44 #include <linux/time.h> 45 #include <linux/init.h> 46 #include <linux/profile.h> 47 #include <linux/cpu.h> 48 #include <linux/security.h> 49 #include <linux/percpu.h> 50 #include <linux/rtc.h> 51 #include <linux/jiffies.h> 52 #include <linux/posix-timers.h> 53 #include <linux/irq.h> 54 #include <linux/delay.h> 55 #include <linux/irq_work.h> 56 #include <asm/trace.h> 57 58 #include <asm/io.h> 59 #include <asm/processor.h> 60 #include <asm/nvram.h> 61 #include <asm/cache.h> 62 #include <asm/machdep.h> 63 #include <asm/uaccess.h> 64 #include <asm/time.h> 65 #include <asm/prom.h> 66 #include <asm/irq.h> 67 #include <asm/div64.h> 68 #include <asm/smp.h> 69 #include <asm/vdso_datapage.h> 70 #include <asm/firmware.h> 71 #include <asm/cputime.h> 72 73 /* powerpc clocksource/clockevent code */ 74 75 #include <linux/clockchips.h> 76 #include <linux/clocksource.h> 77 78 static cycle_t rtc_read(struct clocksource *); 79 static struct clocksource clocksource_rtc = { 80 .name = "rtc", 81 .rating = 400, 82 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 83 .mask = CLOCKSOURCE_MASK(64), 84 .read = rtc_read, 85 }; 86 87 static cycle_t timebase_read(struct clocksource *); 88 static struct clocksource clocksource_timebase = { 89 .name = "timebase", 90 .rating = 400, 91 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 92 .mask = CLOCKSOURCE_MASK(64), 93 .read = timebase_read, 94 }; 95 96 #define DECREMENTER_MAX 0x7fffffff 97 98 static int decrementer_set_next_event(unsigned long evt, 99 struct clock_event_device *dev); 100 static void decrementer_set_mode(enum clock_event_mode mode, 101 struct clock_event_device *dev); 102 103 struct clock_event_device decrementer_clockevent = { 104 .name = "decrementer", 105 .rating = 200, 106 .irq = 0, 107 .set_next_event = decrementer_set_next_event, 108 .set_mode = decrementer_set_mode, 109 .features = CLOCK_EVT_FEAT_ONESHOT, 110 }; 111 EXPORT_SYMBOL(decrementer_clockevent); 112 113 DEFINE_PER_CPU(u64, decrementers_next_tb); 114 static DEFINE_PER_CPU(struct clock_event_device, decrementers); 115 116 #define XSEC_PER_SEC (1024*1024) 117 118 #ifdef CONFIG_PPC64 119 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) 120 #else 121 /* compute ((xsec << 12) * max) >> 32 */ 122 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) 123 #endif 124 125 unsigned long tb_ticks_per_jiffy; 126 unsigned long tb_ticks_per_usec = 100; /* sane default */ 127 EXPORT_SYMBOL(tb_ticks_per_usec); 128 unsigned long tb_ticks_per_sec; 129 EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ 130 131 DEFINE_SPINLOCK(rtc_lock); 132 EXPORT_SYMBOL_GPL(rtc_lock); 133 134 static u64 tb_to_ns_scale __read_mostly; 135 static unsigned tb_to_ns_shift __read_mostly; 136 static u64 boot_tb __read_mostly; 137 138 extern struct timezone sys_tz; 139 static long timezone_offset; 140 141 unsigned long ppc_proc_freq; 142 EXPORT_SYMBOL_GPL(ppc_proc_freq); 143 unsigned long ppc_tb_freq; 144 EXPORT_SYMBOL_GPL(ppc_tb_freq); 145 146 #ifdef CONFIG_VIRT_CPU_ACCOUNTING 147 /* 148 * Factors for converting from cputime_t (timebase ticks) to 149 * jiffies, microseconds, seconds, and clock_t (1/USER_HZ seconds). 150 * These are all stored as 0.64 fixed-point binary fractions. 151 */ 152 u64 __cputime_jiffies_factor; 153 EXPORT_SYMBOL(__cputime_jiffies_factor); 154 u64 __cputime_usec_factor; 155 EXPORT_SYMBOL(__cputime_usec_factor); 156 u64 __cputime_sec_factor; 157 EXPORT_SYMBOL(__cputime_sec_factor); 158 u64 __cputime_clockt_factor; 159 EXPORT_SYMBOL(__cputime_clockt_factor); 160 DEFINE_PER_CPU(unsigned long, cputime_last_delta); 161 DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta); 162 163 cputime_t cputime_one_jiffy; 164 165 void (*dtl_consumer)(struct dtl_entry *, u64); 166 167 static void calc_cputime_factors(void) 168 { 169 struct div_result res; 170 171 div128_by_32(HZ, 0, tb_ticks_per_sec, &res); 172 __cputime_jiffies_factor = res.result_low; 173 div128_by_32(1000000, 0, tb_ticks_per_sec, &res); 174 __cputime_usec_factor = res.result_low; 175 div128_by_32(1, 0, tb_ticks_per_sec, &res); 176 __cputime_sec_factor = res.result_low; 177 div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res); 178 __cputime_clockt_factor = res.result_low; 179 } 180 181 /* 182 * Read the SPURR on systems that have it, otherwise the PURR, 183 * or if that doesn't exist return the timebase value passed in. 184 */ 185 static u64 read_spurr(u64 tb) 186 { 187 if (cpu_has_feature(CPU_FTR_SPURR)) 188 return mfspr(SPRN_SPURR); 189 if (cpu_has_feature(CPU_FTR_PURR)) 190 return mfspr(SPRN_PURR); 191 return tb; 192 } 193 194 #ifdef CONFIG_PPC_SPLPAR 195 196 /* 197 * Scan the dispatch trace log and count up the stolen time. 198 * Should be called with interrupts disabled. 199 */ 200 static u64 scan_dispatch_log(u64 stop_tb) 201 { 202 u64 i = local_paca->dtl_ridx; 203 struct dtl_entry *dtl = local_paca->dtl_curr; 204 struct dtl_entry *dtl_end = local_paca->dispatch_log_end; 205 struct lppaca *vpa = local_paca->lppaca_ptr; 206 u64 tb_delta; 207 u64 stolen = 0; 208 u64 dtb; 209 210 if (!dtl) 211 return 0; 212 213 if (i == vpa->dtl_idx) 214 return 0; 215 while (i < vpa->dtl_idx) { 216 if (dtl_consumer) 217 dtl_consumer(dtl, i); 218 dtb = dtl->timebase; 219 tb_delta = dtl->enqueue_to_dispatch_time + 220 dtl->ready_to_enqueue_time; 221 barrier(); 222 if (i + N_DISPATCH_LOG < vpa->dtl_idx) { 223 /* buffer has overflowed */ 224 i = vpa->dtl_idx - N_DISPATCH_LOG; 225 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG); 226 continue; 227 } 228 if (dtb > stop_tb) 229 break; 230 stolen += tb_delta; 231 ++i; 232 ++dtl; 233 if (dtl == dtl_end) 234 dtl = local_paca->dispatch_log; 235 } 236 local_paca->dtl_ridx = i; 237 local_paca->dtl_curr = dtl; 238 return stolen; 239 } 240 241 /* 242 * Accumulate stolen time by scanning the dispatch trace log. 243 * Called on entry from user mode. 244 */ 245 void accumulate_stolen_time(void) 246 { 247 u64 sst, ust; 248 249 u8 save_soft_enabled = local_paca->soft_enabled; 250 251 /* We are called early in the exception entry, before 252 * soft/hard_enabled are sync'ed to the expected state 253 * for the exception. We are hard disabled but the PACA 254 * needs to reflect that so various debug stuff doesn't 255 * complain 256 */ 257 local_paca->soft_enabled = 0; 258 259 sst = scan_dispatch_log(local_paca->starttime_user); 260 ust = scan_dispatch_log(local_paca->starttime); 261 local_paca->system_time -= sst; 262 local_paca->user_time -= ust; 263 local_paca->stolen_time += ust + sst; 264 265 local_paca->soft_enabled = save_soft_enabled; 266 } 267 268 static inline u64 calculate_stolen_time(u64 stop_tb) 269 { 270 u64 stolen = 0; 271 272 if (get_paca()->dtl_ridx != get_paca()->lppaca_ptr->dtl_idx) { 273 stolen = scan_dispatch_log(stop_tb); 274 get_paca()->system_time -= stolen; 275 } 276 277 stolen += get_paca()->stolen_time; 278 get_paca()->stolen_time = 0; 279 return stolen; 280 } 281 282 #else /* CONFIG_PPC_SPLPAR */ 283 static inline u64 calculate_stolen_time(u64 stop_tb) 284 { 285 return 0; 286 } 287 288 #endif /* CONFIG_PPC_SPLPAR */ 289 290 /* 291 * Account time for a transition between system, hard irq 292 * or soft irq state. 293 */ 294 void account_system_vtime(struct task_struct *tsk) 295 { 296 u64 now, nowscaled, delta, deltascaled; 297 unsigned long flags; 298 u64 stolen, udelta, sys_scaled, user_scaled; 299 300 local_irq_save(flags); 301 now = mftb(); 302 nowscaled = read_spurr(now); 303 get_paca()->system_time += now - get_paca()->starttime; 304 get_paca()->starttime = now; 305 deltascaled = nowscaled - get_paca()->startspurr; 306 get_paca()->startspurr = nowscaled; 307 308 stolen = calculate_stolen_time(now); 309 310 delta = get_paca()->system_time; 311 get_paca()->system_time = 0; 312 udelta = get_paca()->user_time - get_paca()->utime_sspurr; 313 get_paca()->utime_sspurr = get_paca()->user_time; 314 315 /* 316 * Because we don't read the SPURR on every kernel entry/exit, 317 * deltascaled includes both user and system SPURR ticks. 318 * Apportion these ticks to system SPURR ticks and user 319 * SPURR ticks in the same ratio as the system time (delta) 320 * and user time (udelta) values obtained from the timebase 321 * over the same interval. The system ticks get accounted here; 322 * the user ticks get saved up in paca->user_time_scaled to be 323 * used by account_process_tick. 324 */ 325 sys_scaled = delta; 326 user_scaled = udelta; 327 if (deltascaled != delta + udelta) { 328 if (udelta) { 329 sys_scaled = deltascaled * delta / (delta + udelta); 330 user_scaled = deltascaled - sys_scaled; 331 } else { 332 sys_scaled = deltascaled; 333 } 334 } 335 get_paca()->user_time_scaled += user_scaled; 336 337 if (in_interrupt() || idle_task(smp_processor_id()) != tsk) { 338 account_system_time(tsk, 0, delta, sys_scaled); 339 if (stolen) 340 account_steal_time(stolen); 341 } else { 342 account_idle_time(delta + stolen); 343 } 344 local_irq_restore(flags); 345 } 346 EXPORT_SYMBOL_GPL(account_system_vtime); 347 348 /* 349 * Transfer the user and system times accumulated in the paca 350 * by the exception entry and exit code to the generic process 351 * user and system time records. 352 * Must be called with interrupts disabled. 353 * Assumes that account_system_vtime() has been called recently 354 * (i.e. since the last entry from usermode) so that 355 * get_paca()->user_time_scaled is up to date. 356 */ 357 void account_process_tick(struct task_struct *tsk, int user_tick) 358 { 359 cputime_t utime, utimescaled; 360 361 utime = get_paca()->user_time; 362 utimescaled = get_paca()->user_time_scaled; 363 get_paca()->user_time = 0; 364 get_paca()->user_time_scaled = 0; 365 get_paca()->utime_sspurr = 0; 366 account_user_time(tsk, utime, utimescaled); 367 } 368 369 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */ 370 #define calc_cputime_factors() 371 #endif 372 373 void __delay(unsigned long loops) 374 { 375 unsigned long start; 376 int diff; 377 378 if (__USE_RTC()) { 379 start = get_rtcl(); 380 do { 381 /* the RTCL register wraps at 1000000000 */ 382 diff = get_rtcl() - start; 383 if (diff < 0) 384 diff += 1000000000; 385 } while (diff < loops); 386 } else { 387 start = get_tbl(); 388 while (get_tbl() - start < loops) 389 HMT_low(); 390 HMT_medium(); 391 } 392 } 393 EXPORT_SYMBOL(__delay); 394 395 void udelay(unsigned long usecs) 396 { 397 __delay(tb_ticks_per_usec * usecs); 398 } 399 EXPORT_SYMBOL(udelay); 400 401 #ifdef CONFIG_SMP 402 unsigned long profile_pc(struct pt_regs *regs) 403 { 404 unsigned long pc = instruction_pointer(regs); 405 406 if (in_lock_functions(pc)) 407 return regs->link; 408 409 return pc; 410 } 411 EXPORT_SYMBOL(profile_pc); 412 #endif 413 414 #ifdef CONFIG_IRQ_WORK 415 416 /* 417 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable... 418 */ 419 #ifdef CONFIG_PPC64 420 static inline unsigned long test_irq_work_pending(void) 421 { 422 unsigned long x; 423 424 asm volatile("lbz %0,%1(13)" 425 : "=r" (x) 426 : "i" (offsetof(struct paca_struct, irq_work_pending))); 427 return x; 428 } 429 430 static inline void set_irq_work_pending_flag(void) 431 { 432 asm volatile("stb %0,%1(13)" : : 433 "r" (1), 434 "i" (offsetof(struct paca_struct, irq_work_pending))); 435 } 436 437 static inline void clear_irq_work_pending(void) 438 { 439 asm volatile("stb %0,%1(13)" : : 440 "r" (0), 441 "i" (offsetof(struct paca_struct, irq_work_pending))); 442 } 443 444 #else /* 32-bit */ 445 446 DEFINE_PER_CPU(u8, irq_work_pending); 447 448 #define set_irq_work_pending_flag() __get_cpu_var(irq_work_pending) = 1 449 #define test_irq_work_pending() __get_cpu_var(irq_work_pending) 450 #define clear_irq_work_pending() __get_cpu_var(irq_work_pending) = 0 451 452 #endif /* 32 vs 64 bit */ 453 454 void arch_irq_work_raise(void) 455 { 456 preempt_disable(); 457 set_irq_work_pending_flag(); 458 set_dec(1); 459 preempt_enable(); 460 } 461 462 #else /* CONFIG_IRQ_WORK */ 463 464 #define test_irq_work_pending() 0 465 #define clear_irq_work_pending() 466 467 #endif /* CONFIG_IRQ_WORK */ 468 469 /* 470 * timer_interrupt - gets called when the decrementer overflows, 471 * with interrupts disabled. 472 */ 473 void timer_interrupt(struct pt_regs * regs) 474 { 475 struct pt_regs *old_regs; 476 u64 *next_tb = &__get_cpu_var(decrementers_next_tb); 477 struct clock_event_device *evt = &__get_cpu_var(decrementers); 478 479 /* Ensure a positive value is written to the decrementer, or else 480 * some CPUs will continue to take decrementer exceptions. 481 */ 482 set_dec(DECREMENTER_MAX); 483 484 /* Some implementations of hotplug will get timer interrupts while 485 * offline, just ignore these 486 */ 487 if (!cpu_online(smp_processor_id())) 488 return; 489 490 /* Conditionally hard-enable interrupts now that the DEC has been 491 * bumped to its maximum value 492 */ 493 may_hard_irq_enable(); 494 495 trace_timer_interrupt_entry(regs); 496 497 __get_cpu_var(irq_stat).timer_irqs++; 498 499 #if defined(CONFIG_PPC32) && defined(CONFIG_PMAC) 500 if (atomic_read(&ppc_n_lost_interrupts) != 0) 501 do_IRQ(regs); 502 #endif 503 504 old_regs = set_irq_regs(regs); 505 irq_enter(); 506 507 if (test_irq_work_pending()) { 508 clear_irq_work_pending(); 509 irq_work_run(); 510 } 511 512 *next_tb = ~(u64)0; 513 if (evt->event_handler) 514 evt->event_handler(evt); 515 516 #ifdef CONFIG_PPC64 517 /* collect purr register values often, for accurate calculations */ 518 if (firmware_has_feature(FW_FEATURE_SPLPAR)) { 519 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); 520 cu->current_tb = mfspr(SPRN_PURR); 521 } 522 #endif 523 524 irq_exit(); 525 set_irq_regs(old_regs); 526 527 trace_timer_interrupt_exit(regs); 528 } 529 530 #ifdef CONFIG_SUSPEND 531 static void generic_suspend_disable_irqs(void) 532 { 533 /* Disable the decrementer, so that it doesn't interfere 534 * with suspending. 535 */ 536 537 set_dec(DECREMENTER_MAX); 538 local_irq_disable(); 539 set_dec(DECREMENTER_MAX); 540 } 541 542 static void generic_suspend_enable_irqs(void) 543 { 544 local_irq_enable(); 545 } 546 547 /* Overrides the weak version in kernel/power/main.c */ 548 void arch_suspend_disable_irqs(void) 549 { 550 if (ppc_md.suspend_disable_irqs) 551 ppc_md.suspend_disable_irqs(); 552 generic_suspend_disable_irqs(); 553 } 554 555 /* Overrides the weak version in kernel/power/main.c */ 556 void arch_suspend_enable_irqs(void) 557 { 558 generic_suspend_enable_irqs(); 559 if (ppc_md.suspend_enable_irqs) 560 ppc_md.suspend_enable_irqs(); 561 } 562 #endif 563 564 /* 565 * Scheduler clock - returns current time in nanosec units. 566 * 567 * Note: mulhdu(a, b) (multiply high double unsigned) returns 568 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 569 * are 64-bit unsigned numbers. 570 */ 571 unsigned long long sched_clock(void) 572 { 573 if (__USE_RTC()) 574 return get_rtc(); 575 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 576 } 577 578 static int __init get_freq(char *name, int cells, unsigned long *val) 579 { 580 struct device_node *cpu; 581 const unsigned int *fp; 582 int found = 0; 583 584 /* The cpu node should have timebase and clock frequency properties */ 585 cpu = of_find_node_by_type(NULL, "cpu"); 586 587 if (cpu) { 588 fp = of_get_property(cpu, name, NULL); 589 if (fp) { 590 found = 1; 591 *val = of_read_ulong(fp, cells); 592 } 593 594 of_node_put(cpu); 595 } 596 597 return found; 598 } 599 600 /* should become __cpuinit when secondary_cpu_time_init also is */ 601 void start_cpu_decrementer(void) 602 { 603 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) 604 /* Clear any pending timer interrupts */ 605 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 606 607 /* Enable decrementer interrupt */ 608 mtspr(SPRN_TCR, TCR_DIE); 609 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */ 610 } 611 612 void __init generic_calibrate_decr(void) 613 { 614 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 615 616 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 617 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 618 619 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 620 "(not found)\n"); 621 } 622 623 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 624 625 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 626 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 627 628 printk(KERN_ERR "WARNING: Estimating processor frequency " 629 "(not found)\n"); 630 } 631 } 632 633 int update_persistent_clock(struct timespec now) 634 { 635 struct rtc_time tm; 636 637 if (!ppc_md.set_rtc_time) 638 return 0; 639 640 to_tm(now.tv_sec + 1 + timezone_offset, &tm); 641 tm.tm_year -= 1900; 642 tm.tm_mon -= 1; 643 644 return ppc_md.set_rtc_time(&tm); 645 } 646 647 static void __read_persistent_clock(struct timespec *ts) 648 { 649 struct rtc_time tm; 650 static int first = 1; 651 652 ts->tv_nsec = 0; 653 /* XXX this is a litle fragile but will work okay in the short term */ 654 if (first) { 655 first = 0; 656 if (ppc_md.time_init) 657 timezone_offset = ppc_md.time_init(); 658 659 /* get_boot_time() isn't guaranteed to be safe to call late */ 660 if (ppc_md.get_boot_time) { 661 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 662 return; 663 } 664 } 665 if (!ppc_md.get_rtc_time) { 666 ts->tv_sec = 0; 667 return; 668 } 669 ppc_md.get_rtc_time(&tm); 670 671 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, 672 tm.tm_hour, tm.tm_min, tm.tm_sec); 673 } 674 675 void read_persistent_clock(struct timespec *ts) 676 { 677 __read_persistent_clock(ts); 678 679 /* Sanitize it in case real time clock is set below EPOCH */ 680 if (ts->tv_sec < 0) { 681 ts->tv_sec = 0; 682 ts->tv_nsec = 0; 683 } 684 685 } 686 687 /* clocksource code */ 688 static cycle_t rtc_read(struct clocksource *cs) 689 { 690 return (cycle_t)get_rtc(); 691 } 692 693 static cycle_t timebase_read(struct clocksource *cs) 694 { 695 return (cycle_t)get_tb(); 696 } 697 698 void update_vsyscall(struct timespec *wall_time, struct timespec *wtm, 699 struct clocksource *clock, u32 mult) 700 { 701 u64 new_tb_to_xs, new_stamp_xsec; 702 u32 frac_sec; 703 704 if (clock != &clocksource_timebase) 705 return; 706 707 /* Make userspace gettimeofday spin until we're done. */ 708 ++vdso_data->tb_update_count; 709 smp_mb(); 710 711 /* 19342813113834067 ~= 2^(20+64) / 1e9 */ 712 new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift); 713 new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC; 714 do_div(new_stamp_xsec, 1000000000); 715 new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC; 716 717 BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC); 718 /* this is tv_nsec / 1e9 as a 0.32 fraction */ 719 frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32; 720 721 /* 722 * tb_update_count is used to allow the userspace gettimeofday code 723 * to assure itself that it sees a consistent view of the tb_to_xs and 724 * stamp_xsec variables. It reads the tb_update_count, then reads 725 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If 726 * the two values of tb_update_count match and are even then the 727 * tb_to_xs and stamp_xsec values are consistent. If not, then it 728 * loops back and reads them again until this criteria is met. 729 * We expect the caller to have done the first increment of 730 * vdso_data->tb_update_count already. 731 */ 732 vdso_data->tb_orig_stamp = clock->cycle_last; 733 vdso_data->stamp_xsec = new_stamp_xsec; 734 vdso_data->tb_to_xs = new_tb_to_xs; 735 vdso_data->wtom_clock_sec = wtm->tv_sec; 736 vdso_data->wtom_clock_nsec = wtm->tv_nsec; 737 vdso_data->stamp_xtime = *wall_time; 738 vdso_data->stamp_sec_fraction = frac_sec; 739 smp_wmb(); 740 ++(vdso_data->tb_update_count); 741 } 742 743 void update_vsyscall_tz(void) 744 { 745 /* Make userspace gettimeofday spin until we're done. */ 746 ++vdso_data->tb_update_count; 747 smp_mb(); 748 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; 749 vdso_data->tz_dsttime = sys_tz.tz_dsttime; 750 smp_mb(); 751 ++vdso_data->tb_update_count; 752 } 753 754 static void __init clocksource_init(void) 755 { 756 struct clocksource *clock; 757 758 if (__USE_RTC()) 759 clock = &clocksource_rtc; 760 else 761 clock = &clocksource_timebase; 762 763 if (clocksource_register_hz(clock, tb_ticks_per_sec)) { 764 printk(KERN_ERR "clocksource: %s is already registered\n", 765 clock->name); 766 return; 767 } 768 769 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 770 clock->name, clock->mult, clock->shift); 771 } 772 773 static int decrementer_set_next_event(unsigned long evt, 774 struct clock_event_device *dev) 775 { 776 __get_cpu_var(decrementers_next_tb) = get_tb_or_rtc() + evt; 777 set_dec(evt); 778 return 0; 779 } 780 781 static void decrementer_set_mode(enum clock_event_mode mode, 782 struct clock_event_device *dev) 783 { 784 if (mode != CLOCK_EVT_MODE_ONESHOT) 785 decrementer_set_next_event(DECREMENTER_MAX, dev); 786 } 787 788 static void register_decrementer_clockevent(int cpu) 789 { 790 struct clock_event_device *dec = &per_cpu(decrementers, cpu); 791 792 *dec = decrementer_clockevent; 793 dec->cpumask = cpumask_of(cpu); 794 795 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 796 dec->name, dec->mult, dec->shift, cpu); 797 798 clockevents_register_device(dec); 799 } 800 801 static void __init init_decrementer_clockevent(void) 802 { 803 int cpu = smp_processor_id(); 804 805 clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4); 806 807 decrementer_clockevent.max_delta_ns = 808 clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent); 809 decrementer_clockevent.min_delta_ns = 810 clockevent_delta2ns(2, &decrementer_clockevent); 811 812 register_decrementer_clockevent(cpu); 813 } 814 815 void secondary_cpu_time_init(void) 816 { 817 /* Start the decrementer on CPUs that have manual control 818 * such as BookE 819 */ 820 start_cpu_decrementer(); 821 822 /* FIME: Should make unrelatred change to move snapshot_timebase 823 * call here ! */ 824 register_decrementer_clockevent(smp_processor_id()); 825 } 826 827 /* This function is only called on the boot processor */ 828 void __init time_init(void) 829 { 830 struct div_result res; 831 u64 scale; 832 unsigned shift; 833 834 if (__USE_RTC()) { 835 /* 601 processor: dec counts down by 128 every 128ns */ 836 ppc_tb_freq = 1000000000; 837 } else { 838 /* Normal PowerPC with timebase register */ 839 ppc_md.calibrate_decr(); 840 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 841 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 842 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 843 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 844 } 845 846 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 847 tb_ticks_per_sec = ppc_tb_freq; 848 tb_ticks_per_usec = ppc_tb_freq / 1000000; 849 calc_cputime_factors(); 850 setup_cputime_one_jiffy(); 851 852 /* 853 * Compute scale factor for sched_clock. 854 * The calibrate_decr() function has set tb_ticks_per_sec, 855 * which is the timebase frequency. 856 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 857 * the 128-bit result as a 64.64 fixed-point number. 858 * We then shift that number right until it is less than 1.0, 859 * giving us the scale factor and shift count to use in 860 * sched_clock(). 861 */ 862 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 863 scale = res.result_low; 864 for (shift = 0; res.result_high != 0; ++shift) { 865 scale = (scale >> 1) | (res.result_high << 63); 866 res.result_high >>= 1; 867 } 868 tb_to_ns_scale = scale; 869 tb_to_ns_shift = shift; 870 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 871 boot_tb = get_tb_or_rtc(); 872 873 /* If platform provided a timezone (pmac), we correct the time */ 874 if (timezone_offset) { 875 sys_tz.tz_minuteswest = -timezone_offset / 60; 876 sys_tz.tz_dsttime = 0; 877 } 878 879 vdso_data->tb_update_count = 0; 880 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 881 882 /* Start the decrementer on CPUs that have manual control 883 * such as BookE 884 */ 885 start_cpu_decrementer(); 886 887 /* Register the clocksource */ 888 clocksource_init(); 889 890 init_decrementer_clockevent(); 891 } 892 893 894 #define FEBRUARY 2 895 #define STARTOFTIME 1970 896 #define SECDAY 86400L 897 #define SECYR (SECDAY * 365) 898 #define leapyear(year) ((year) % 4 == 0 && \ 899 ((year) % 100 != 0 || (year) % 400 == 0)) 900 #define days_in_year(a) (leapyear(a) ? 366 : 365) 901 #define days_in_month(a) (month_days[(a) - 1]) 902 903 static int month_days[12] = { 904 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 905 }; 906 907 /* 908 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) 909 */ 910 void GregorianDay(struct rtc_time * tm) 911 { 912 int leapsToDate; 913 int lastYear; 914 int day; 915 int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; 916 917 lastYear = tm->tm_year - 1; 918 919 /* 920 * Number of leap corrections to apply up to end of last year 921 */ 922 leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400; 923 924 /* 925 * This year is a leap year if it is divisible by 4 except when it is 926 * divisible by 100 unless it is divisible by 400 927 * 928 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was 929 */ 930 day = tm->tm_mon > 2 && leapyear(tm->tm_year); 931 932 day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + 933 tm->tm_mday; 934 935 tm->tm_wday = day % 7; 936 } 937 938 void to_tm(int tim, struct rtc_time * tm) 939 { 940 register int i; 941 register long hms, day; 942 943 day = tim / SECDAY; 944 hms = tim % SECDAY; 945 946 /* Hours, minutes, seconds are easy */ 947 tm->tm_hour = hms / 3600; 948 tm->tm_min = (hms % 3600) / 60; 949 tm->tm_sec = (hms % 3600) % 60; 950 951 /* Number of years in days */ 952 for (i = STARTOFTIME; day >= days_in_year(i); i++) 953 day -= days_in_year(i); 954 tm->tm_year = i; 955 956 /* Number of months in days left */ 957 if (leapyear(tm->tm_year)) 958 days_in_month(FEBRUARY) = 29; 959 for (i = 1; day >= days_in_month(i); i++) 960 day -= days_in_month(i); 961 days_in_month(FEBRUARY) = 28; 962 tm->tm_mon = i; 963 964 /* Days are what is left over (+1) from all that. */ 965 tm->tm_mday = day + 1; 966 967 /* 968 * Determine the day of week 969 */ 970 GregorianDay(tm); 971 } 972 973 /* 974 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 975 * result. 976 */ 977 void div128_by_32(u64 dividend_high, u64 dividend_low, 978 unsigned divisor, struct div_result *dr) 979 { 980 unsigned long a, b, c, d; 981 unsigned long w, x, y, z; 982 u64 ra, rb, rc; 983 984 a = dividend_high >> 32; 985 b = dividend_high & 0xffffffff; 986 c = dividend_low >> 32; 987 d = dividend_low & 0xffffffff; 988 989 w = a / divisor; 990 ra = ((u64)(a - (w * divisor)) << 32) + b; 991 992 rb = ((u64) do_div(ra, divisor) << 32) + c; 993 x = ra; 994 995 rc = ((u64) do_div(rb, divisor) << 32) + d; 996 y = rb; 997 998 do_div(rc, divisor); 999 z = rc; 1000 1001 dr->result_high = ((u64)w << 32) + x; 1002 dr->result_low = ((u64)y << 32) + z; 1003 1004 } 1005 1006 /* We don't need to calibrate delay, we use the CPU timebase for that */ 1007 void calibrate_delay(void) 1008 { 1009 /* Some generic code (such as spinlock debug) use loops_per_jiffy 1010 * as the number of __delay(1) in a jiffy, so make it so 1011 */ 1012 loops_per_jiffy = tb_ticks_per_jiffy; 1013 } 1014 1015 static int __init rtc_init(void) 1016 { 1017 struct platform_device *pdev; 1018 1019 if (!ppc_md.get_rtc_time) 1020 return -ENODEV; 1021 1022 pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0); 1023 if (IS_ERR(pdev)) 1024 return PTR_ERR(pdev); 1025 1026 return 0; 1027 } 1028 1029 module_init(rtc_init); 1030