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