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 #include <linux/delay.h> 56 #include <linux/irq_work.h> 57 #include <asm/trace.h> 58 59 #include <asm/io.h> 60 #include <asm/processor.h> 61 #include <asm/nvram.h> 62 #include <asm/cache.h> 63 #include <asm/machdep.h> 64 #include <asm/uaccess.h> 65 #include <asm/time.h> 66 #include <asm/prom.h> 67 #include <asm/irq.h> 68 #include <asm/div64.h> 69 #include <asm/smp.h> 70 #include <asm/vdso_datapage.h> 71 #include <asm/firmware.h> 72 #include <asm/cputime.h> 73 #ifdef CONFIG_PPC_ISERIES 74 #include <asm/iseries/it_lp_queue.h> 75 #include <asm/iseries/hv_call_xm.h> 76 #endif 77 78 /* powerpc clocksource/clockevent code */ 79 80 #include <linux/clockchips.h> 81 #include <linux/clocksource.h> 82 83 static cycle_t rtc_read(struct clocksource *); 84 static struct clocksource clocksource_rtc = { 85 .name = "rtc", 86 .rating = 400, 87 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 88 .mask = CLOCKSOURCE_MASK(64), 89 .shift = 22, 90 .mult = 0, /* To be filled in */ 91 .read = rtc_read, 92 }; 93 94 static cycle_t timebase_read(struct clocksource *); 95 static struct clocksource clocksource_timebase = { 96 .name = "timebase", 97 .rating = 400, 98 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 99 .mask = CLOCKSOURCE_MASK(64), 100 .shift = 22, 101 .mult = 0, /* To be filled in */ 102 .read = timebase_read, 103 }; 104 105 #define DECREMENTER_MAX 0x7fffffff 106 107 static int decrementer_set_next_event(unsigned long evt, 108 struct clock_event_device *dev); 109 static void decrementer_set_mode(enum clock_event_mode mode, 110 struct clock_event_device *dev); 111 112 static struct clock_event_device decrementer_clockevent = { 113 .name = "decrementer", 114 .rating = 200, 115 .shift = 0, /* To be filled in */ 116 .mult = 0, /* To be filled in */ 117 .irq = 0, 118 .set_next_event = decrementer_set_next_event, 119 .set_mode = decrementer_set_mode, 120 .features = CLOCK_EVT_FEAT_ONESHOT, 121 }; 122 123 struct decrementer_clock { 124 struct clock_event_device event; 125 u64 next_tb; 126 }; 127 128 static DEFINE_PER_CPU(struct decrementer_clock, decrementers); 129 130 #ifdef CONFIG_PPC_ISERIES 131 static unsigned long __initdata iSeries_recal_titan; 132 static signed long __initdata iSeries_recal_tb; 133 134 /* Forward declaration is only needed for iSereis compiles */ 135 static void __init clocksource_init(void); 136 #endif 137 138 #define XSEC_PER_SEC (1024*1024) 139 140 #ifdef CONFIG_PPC64 141 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) 142 #else 143 /* compute ((xsec << 12) * max) >> 32 */ 144 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) 145 #endif 146 147 unsigned long tb_ticks_per_jiffy; 148 unsigned long tb_ticks_per_usec = 100; /* sane default */ 149 EXPORT_SYMBOL(tb_ticks_per_usec); 150 unsigned long tb_ticks_per_sec; 151 EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ 152 153 DEFINE_SPINLOCK(rtc_lock); 154 EXPORT_SYMBOL_GPL(rtc_lock); 155 156 static u64 tb_to_ns_scale __read_mostly; 157 static unsigned tb_to_ns_shift __read_mostly; 158 static u64 boot_tb __read_mostly; 159 160 extern struct timezone sys_tz; 161 static long timezone_offset; 162 163 unsigned long ppc_proc_freq; 164 EXPORT_SYMBOL_GPL(ppc_proc_freq); 165 unsigned long ppc_tb_freq; 166 EXPORT_SYMBOL_GPL(ppc_tb_freq); 167 168 #ifdef CONFIG_VIRT_CPU_ACCOUNTING 169 /* 170 * Factors for converting from cputime_t (timebase ticks) to 171 * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds). 172 * These are all stored as 0.64 fixed-point binary fractions. 173 */ 174 u64 __cputime_jiffies_factor; 175 EXPORT_SYMBOL(__cputime_jiffies_factor); 176 u64 __cputime_msec_factor; 177 EXPORT_SYMBOL(__cputime_msec_factor); 178 u64 __cputime_sec_factor; 179 EXPORT_SYMBOL(__cputime_sec_factor); 180 u64 __cputime_clockt_factor; 181 EXPORT_SYMBOL(__cputime_clockt_factor); 182 DEFINE_PER_CPU(unsigned long, cputime_last_delta); 183 DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta); 184 185 cputime_t cputime_one_jiffy; 186 187 void (*dtl_consumer)(struct dtl_entry *, u64); 188 189 static void calc_cputime_factors(void) 190 { 191 struct div_result res; 192 193 div128_by_32(HZ, 0, tb_ticks_per_sec, &res); 194 __cputime_jiffies_factor = res.result_low; 195 div128_by_32(1000, 0, tb_ticks_per_sec, &res); 196 __cputime_msec_factor = res.result_low; 197 div128_by_32(1, 0, tb_ticks_per_sec, &res); 198 __cputime_sec_factor = res.result_low; 199 div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res); 200 __cputime_clockt_factor = res.result_low; 201 } 202 203 /* 204 * Read the SPURR on systems that have it, otherwise the PURR, 205 * or if that doesn't exist return the timebase value passed in. 206 */ 207 static u64 read_spurr(u64 tb) 208 { 209 if (cpu_has_feature(CPU_FTR_SPURR)) 210 return mfspr(SPRN_SPURR); 211 if (cpu_has_feature(CPU_FTR_PURR)) 212 return mfspr(SPRN_PURR); 213 return tb; 214 } 215 216 #ifdef CONFIG_PPC_SPLPAR 217 218 /* 219 * Scan the dispatch trace log and count up the stolen time. 220 * Should be called with interrupts disabled. 221 */ 222 static u64 scan_dispatch_log(u64 stop_tb) 223 { 224 u64 i = local_paca->dtl_ridx; 225 struct dtl_entry *dtl = local_paca->dtl_curr; 226 struct dtl_entry *dtl_end = local_paca->dispatch_log_end; 227 struct lppaca *vpa = local_paca->lppaca_ptr; 228 u64 tb_delta; 229 u64 stolen = 0; 230 u64 dtb; 231 232 if (!dtl) 233 return 0; 234 235 if (i == vpa->dtl_idx) 236 return 0; 237 while (i < vpa->dtl_idx) { 238 if (dtl_consumer) 239 dtl_consumer(dtl, i); 240 dtb = dtl->timebase; 241 tb_delta = dtl->enqueue_to_dispatch_time + 242 dtl->ready_to_enqueue_time; 243 barrier(); 244 if (i + N_DISPATCH_LOG < vpa->dtl_idx) { 245 /* buffer has overflowed */ 246 i = vpa->dtl_idx - N_DISPATCH_LOG; 247 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG); 248 continue; 249 } 250 if (dtb > stop_tb) 251 break; 252 stolen += tb_delta; 253 ++i; 254 ++dtl; 255 if (dtl == dtl_end) 256 dtl = local_paca->dispatch_log; 257 } 258 local_paca->dtl_ridx = i; 259 local_paca->dtl_curr = dtl; 260 return stolen; 261 } 262 263 /* 264 * Accumulate stolen time by scanning the dispatch trace log. 265 * Called on entry from user mode. 266 */ 267 void accumulate_stolen_time(void) 268 { 269 u64 sst, ust; 270 271 u8 save_soft_enabled = local_paca->soft_enabled; 272 u8 save_hard_enabled = local_paca->hard_enabled; 273 274 /* We are called early in the exception entry, before 275 * soft/hard_enabled are sync'ed to the expected state 276 * for the exception. We are hard disabled but the PACA 277 * needs to reflect that so various debug stuff doesn't 278 * complain 279 */ 280 local_paca->soft_enabled = 0; 281 local_paca->hard_enabled = 0; 282 283 sst = scan_dispatch_log(local_paca->starttime_user); 284 ust = scan_dispatch_log(local_paca->starttime); 285 local_paca->system_time -= sst; 286 local_paca->user_time -= ust; 287 local_paca->stolen_time += ust + sst; 288 289 local_paca->soft_enabled = save_soft_enabled; 290 local_paca->hard_enabled = save_hard_enabled; 291 } 292 293 static inline u64 calculate_stolen_time(u64 stop_tb) 294 { 295 u64 stolen = 0; 296 297 if (get_paca()->dtl_ridx != get_paca()->lppaca_ptr->dtl_idx) { 298 stolen = scan_dispatch_log(stop_tb); 299 get_paca()->system_time -= stolen; 300 } 301 302 stolen += get_paca()->stolen_time; 303 get_paca()->stolen_time = 0; 304 return stolen; 305 } 306 307 #else /* CONFIG_PPC_SPLPAR */ 308 static inline u64 calculate_stolen_time(u64 stop_tb) 309 { 310 return 0; 311 } 312 313 #endif /* CONFIG_PPC_SPLPAR */ 314 315 /* 316 * Account time for a transition between system, hard irq 317 * or soft irq state. 318 */ 319 void account_system_vtime(struct task_struct *tsk) 320 { 321 u64 now, nowscaled, delta, deltascaled; 322 unsigned long flags; 323 u64 stolen, udelta, sys_scaled, user_scaled; 324 325 local_irq_save(flags); 326 now = mftb(); 327 nowscaled = read_spurr(now); 328 get_paca()->system_time += now - get_paca()->starttime; 329 get_paca()->starttime = now; 330 deltascaled = nowscaled - get_paca()->startspurr; 331 get_paca()->startspurr = nowscaled; 332 333 stolen = calculate_stolen_time(now); 334 335 delta = get_paca()->system_time; 336 get_paca()->system_time = 0; 337 udelta = get_paca()->user_time - get_paca()->utime_sspurr; 338 get_paca()->utime_sspurr = get_paca()->user_time; 339 340 /* 341 * Because we don't read the SPURR on every kernel entry/exit, 342 * deltascaled includes both user and system SPURR ticks. 343 * Apportion these ticks to system SPURR ticks and user 344 * SPURR ticks in the same ratio as the system time (delta) 345 * and user time (udelta) values obtained from the timebase 346 * over the same interval. The system ticks get accounted here; 347 * the user ticks get saved up in paca->user_time_scaled to be 348 * used by account_process_tick. 349 */ 350 sys_scaled = delta; 351 user_scaled = udelta; 352 if (deltascaled != delta + udelta) { 353 if (udelta) { 354 sys_scaled = deltascaled * delta / (delta + udelta); 355 user_scaled = deltascaled - sys_scaled; 356 } else { 357 sys_scaled = deltascaled; 358 } 359 } 360 get_paca()->user_time_scaled += user_scaled; 361 362 if (in_interrupt() || idle_task(smp_processor_id()) != tsk) { 363 account_system_time(tsk, 0, delta, sys_scaled); 364 if (stolen) 365 account_steal_time(stolen); 366 } else { 367 account_idle_time(delta + stolen); 368 } 369 local_irq_restore(flags); 370 } 371 EXPORT_SYMBOL_GPL(account_system_vtime); 372 373 /* 374 * Transfer the user and system times accumulated in the paca 375 * by the exception entry and exit code to the generic process 376 * user and system time records. 377 * Must be called with interrupts disabled. 378 * Assumes that account_system_vtime() has been called recently 379 * (i.e. since the last entry from usermode) so that 380 * get_paca()->user_time_scaled is up to date. 381 */ 382 void account_process_tick(struct task_struct *tsk, int user_tick) 383 { 384 cputime_t utime, utimescaled; 385 386 utime = get_paca()->user_time; 387 utimescaled = get_paca()->user_time_scaled; 388 get_paca()->user_time = 0; 389 get_paca()->user_time_scaled = 0; 390 get_paca()->utime_sspurr = 0; 391 account_user_time(tsk, utime, utimescaled); 392 } 393 394 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */ 395 #define calc_cputime_factors() 396 #endif 397 398 void __delay(unsigned long loops) 399 { 400 unsigned long start; 401 int diff; 402 403 if (__USE_RTC()) { 404 start = get_rtcl(); 405 do { 406 /* the RTCL register wraps at 1000000000 */ 407 diff = get_rtcl() - start; 408 if (diff < 0) 409 diff += 1000000000; 410 } while (diff < loops); 411 } else { 412 start = get_tbl(); 413 while (get_tbl() - start < loops) 414 HMT_low(); 415 HMT_medium(); 416 } 417 } 418 EXPORT_SYMBOL(__delay); 419 420 void udelay(unsigned long usecs) 421 { 422 __delay(tb_ticks_per_usec * usecs); 423 } 424 EXPORT_SYMBOL(udelay); 425 426 #ifdef CONFIG_SMP 427 unsigned long profile_pc(struct pt_regs *regs) 428 { 429 unsigned long pc = instruction_pointer(regs); 430 431 if (in_lock_functions(pc)) 432 return regs->link; 433 434 return pc; 435 } 436 EXPORT_SYMBOL(profile_pc); 437 #endif 438 439 #ifdef CONFIG_PPC_ISERIES 440 441 /* 442 * This function recalibrates the timebase based on the 49-bit time-of-day 443 * value in the Titan chip. The Titan is much more accurate than the value 444 * returned by the service processor for the timebase frequency. 445 */ 446 447 static int __init iSeries_tb_recal(void) 448 { 449 unsigned long titan, tb; 450 451 /* Make sure we only run on iSeries */ 452 if (!firmware_has_feature(FW_FEATURE_ISERIES)) 453 return -ENODEV; 454 455 tb = get_tb(); 456 titan = HvCallXm_loadTod(); 457 if ( iSeries_recal_titan ) { 458 unsigned long tb_ticks = tb - iSeries_recal_tb; 459 unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12; 460 unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec; 461 unsigned long new_tb_ticks_per_jiffy = 462 DIV_ROUND_CLOSEST(new_tb_ticks_per_sec, HZ); 463 long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy; 464 char sign = '+'; 465 /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */ 466 new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ; 467 468 if ( tick_diff < 0 ) { 469 tick_diff = -tick_diff; 470 sign = '-'; 471 } 472 if ( tick_diff ) { 473 if ( tick_diff < tb_ticks_per_jiffy/25 ) { 474 printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n", 475 new_tb_ticks_per_jiffy, sign, tick_diff ); 476 tb_ticks_per_jiffy = new_tb_ticks_per_jiffy; 477 tb_ticks_per_sec = new_tb_ticks_per_sec; 478 calc_cputime_factors(); 479 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 480 setup_cputime_one_jiffy(); 481 } 482 else { 483 printk( "Titan recalibrate: FAILED (difference > 4 percent)\n" 484 " new tb_ticks_per_jiffy = %lu\n" 485 " old tb_ticks_per_jiffy = %lu\n", 486 new_tb_ticks_per_jiffy, tb_ticks_per_jiffy ); 487 } 488 } 489 } 490 iSeries_recal_titan = titan; 491 iSeries_recal_tb = tb; 492 493 /* Called here as now we know accurate values for the timebase */ 494 clocksource_init(); 495 return 0; 496 } 497 late_initcall(iSeries_tb_recal); 498 499 /* Called from platform early init */ 500 void __init iSeries_time_init_early(void) 501 { 502 iSeries_recal_tb = get_tb(); 503 iSeries_recal_titan = HvCallXm_loadTod(); 504 } 505 #endif /* CONFIG_PPC_ISERIES */ 506 507 #ifdef CONFIG_IRQ_WORK 508 509 /* 510 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable... 511 */ 512 #ifdef CONFIG_PPC64 513 static inline unsigned long test_irq_work_pending(void) 514 { 515 unsigned long x; 516 517 asm volatile("lbz %0,%1(13)" 518 : "=r" (x) 519 : "i" (offsetof(struct paca_struct, irq_work_pending))); 520 return x; 521 } 522 523 static inline void set_irq_work_pending_flag(void) 524 { 525 asm volatile("stb %0,%1(13)" : : 526 "r" (1), 527 "i" (offsetof(struct paca_struct, irq_work_pending))); 528 } 529 530 static inline void clear_irq_work_pending(void) 531 { 532 asm volatile("stb %0,%1(13)" : : 533 "r" (0), 534 "i" (offsetof(struct paca_struct, irq_work_pending))); 535 } 536 537 #else /* 32-bit */ 538 539 DEFINE_PER_CPU(u8, irq_work_pending); 540 541 #define set_irq_work_pending_flag() __get_cpu_var(irq_work_pending) = 1 542 #define test_irq_work_pending() __get_cpu_var(irq_work_pending) 543 #define clear_irq_work_pending() __get_cpu_var(irq_work_pending) = 0 544 545 #endif /* 32 vs 64 bit */ 546 547 void arch_irq_work_raise(void) 548 { 549 preempt_disable(); 550 set_irq_work_pending_flag(); 551 set_dec(1); 552 preempt_enable(); 553 } 554 555 #else /* CONFIG_IRQ_WORK */ 556 557 #define test_irq_work_pending() 0 558 #define clear_irq_work_pending() 559 560 #endif /* CONFIG_IRQ_WORK */ 561 562 /* 563 * For iSeries shared processors, we have to let the hypervisor 564 * set the hardware decrementer. We set a virtual decrementer 565 * in the lppaca and call the hypervisor if the virtual 566 * decrementer is less than the current value in the hardware 567 * decrementer. (almost always the new decrementer value will 568 * be greater than the current hardware decementer so the hypervisor 569 * call will not be needed) 570 */ 571 572 /* 573 * timer_interrupt - gets called when the decrementer overflows, 574 * with interrupts disabled. 575 */ 576 void timer_interrupt(struct pt_regs * regs) 577 { 578 struct pt_regs *old_regs; 579 struct decrementer_clock *decrementer = &__get_cpu_var(decrementers); 580 struct clock_event_device *evt = &decrementer->event; 581 u64 now; 582 583 /* Ensure a positive value is written to the decrementer, or else 584 * some CPUs will continue to take decrementer exceptions. 585 */ 586 set_dec(DECREMENTER_MAX); 587 588 /* Some implementations of hotplug will get timer interrupts while 589 * offline, just ignore these 590 */ 591 if (!cpu_online(smp_processor_id())) 592 return; 593 594 trace_timer_interrupt_entry(regs); 595 596 __get_cpu_var(irq_stat).timer_irqs++; 597 598 #if defined(CONFIG_PPC32) && defined(CONFIG_PMAC) 599 if (atomic_read(&ppc_n_lost_interrupts) != 0) 600 do_IRQ(regs); 601 #endif 602 603 old_regs = set_irq_regs(regs); 604 irq_enter(); 605 606 if (test_irq_work_pending()) { 607 clear_irq_work_pending(); 608 irq_work_run(); 609 } 610 611 #ifdef CONFIG_PPC_ISERIES 612 if (firmware_has_feature(FW_FEATURE_ISERIES)) 613 get_lppaca()->int_dword.fields.decr_int = 0; 614 #endif 615 616 now = get_tb_or_rtc(); 617 if (now >= decrementer->next_tb) { 618 decrementer->next_tb = ~(u64)0; 619 if (evt->event_handler) 620 evt->event_handler(evt); 621 } else { 622 now = decrementer->next_tb - now; 623 if (now <= DECREMENTER_MAX) 624 set_dec((int)now); 625 } 626 627 #ifdef CONFIG_PPC_ISERIES 628 if (firmware_has_feature(FW_FEATURE_ISERIES) && hvlpevent_is_pending()) 629 process_hvlpevents(); 630 #endif 631 632 #ifdef CONFIG_PPC64 633 /* collect purr register values often, for accurate calculations */ 634 if (firmware_has_feature(FW_FEATURE_SPLPAR)) { 635 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); 636 cu->current_tb = mfspr(SPRN_PURR); 637 } 638 #endif 639 640 irq_exit(); 641 set_irq_regs(old_regs); 642 643 trace_timer_interrupt_exit(regs); 644 } 645 646 #ifdef CONFIG_SUSPEND 647 static void generic_suspend_disable_irqs(void) 648 { 649 /* Disable the decrementer, so that it doesn't interfere 650 * with suspending. 651 */ 652 653 set_dec(0x7fffffff); 654 local_irq_disable(); 655 set_dec(0x7fffffff); 656 } 657 658 static void generic_suspend_enable_irqs(void) 659 { 660 local_irq_enable(); 661 } 662 663 /* Overrides the weak version in kernel/power/main.c */ 664 void arch_suspend_disable_irqs(void) 665 { 666 if (ppc_md.suspend_disable_irqs) 667 ppc_md.suspend_disable_irqs(); 668 generic_suspend_disable_irqs(); 669 } 670 671 /* Overrides the weak version in kernel/power/main.c */ 672 void arch_suspend_enable_irqs(void) 673 { 674 generic_suspend_enable_irqs(); 675 if (ppc_md.suspend_enable_irqs) 676 ppc_md.suspend_enable_irqs(); 677 } 678 #endif 679 680 /* 681 * Scheduler clock - returns current time in nanosec units. 682 * 683 * Note: mulhdu(a, b) (multiply high double unsigned) returns 684 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 685 * are 64-bit unsigned numbers. 686 */ 687 unsigned long long sched_clock(void) 688 { 689 if (__USE_RTC()) 690 return get_rtc(); 691 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 692 } 693 694 static int __init get_freq(char *name, int cells, unsigned long *val) 695 { 696 struct device_node *cpu; 697 const unsigned int *fp; 698 int found = 0; 699 700 /* The cpu node should have timebase and clock frequency properties */ 701 cpu = of_find_node_by_type(NULL, "cpu"); 702 703 if (cpu) { 704 fp = of_get_property(cpu, name, NULL); 705 if (fp) { 706 found = 1; 707 *val = of_read_ulong(fp, cells); 708 } 709 710 of_node_put(cpu); 711 } 712 713 return found; 714 } 715 716 /* should become __cpuinit when secondary_cpu_time_init also is */ 717 void start_cpu_decrementer(void) 718 { 719 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) 720 /* Clear any pending timer interrupts */ 721 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 722 723 /* Enable decrementer interrupt */ 724 mtspr(SPRN_TCR, TCR_DIE); 725 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */ 726 } 727 728 void __init generic_calibrate_decr(void) 729 { 730 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 731 732 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 733 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 734 735 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 736 "(not found)\n"); 737 } 738 739 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 740 741 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 742 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 743 744 printk(KERN_ERR "WARNING: Estimating processor frequency " 745 "(not found)\n"); 746 } 747 } 748 749 int update_persistent_clock(struct timespec now) 750 { 751 struct rtc_time tm; 752 753 if (!ppc_md.set_rtc_time) 754 return 0; 755 756 to_tm(now.tv_sec + 1 + timezone_offset, &tm); 757 tm.tm_year -= 1900; 758 tm.tm_mon -= 1; 759 760 return ppc_md.set_rtc_time(&tm); 761 } 762 763 static void __read_persistent_clock(struct timespec *ts) 764 { 765 struct rtc_time tm; 766 static int first = 1; 767 768 ts->tv_nsec = 0; 769 /* XXX this is a litle fragile but will work okay in the short term */ 770 if (first) { 771 first = 0; 772 if (ppc_md.time_init) 773 timezone_offset = ppc_md.time_init(); 774 775 /* get_boot_time() isn't guaranteed to be safe to call late */ 776 if (ppc_md.get_boot_time) { 777 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 778 return; 779 } 780 } 781 if (!ppc_md.get_rtc_time) { 782 ts->tv_sec = 0; 783 return; 784 } 785 ppc_md.get_rtc_time(&tm); 786 787 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, 788 tm.tm_hour, tm.tm_min, tm.tm_sec); 789 } 790 791 void read_persistent_clock(struct timespec *ts) 792 { 793 __read_persistent_clock(ts); 794 795 /* Sanitize it in case real time clock is set below EPOCH */ 796 if (ts->tv_sec < 0) { 797 ts->tv_sec = 0; 798 ts->tv_nsec = 0; 799 } 800 801 } 802 803 /* clocksource code */ 804 static cycle_t rtc_read(struct clocksource *cs) 805 { 806 return (cycle_t)get_rtc(); 807 } 808 809 static cycle_t timebase_read(struct clocksource *cs) 810 { 811 return (cycle_t)get_tb(); 812 } 813 814 void update_vsyscall(struct timespec *wall_time, struct timespec *wtm, 815 struct clocksource *clock, u32 mult) 816 { 817 u64 new_tb_to_xs, new_stamp_xsec; 818 u32 frac_sec; 819 820 if (clock != &clocksource_timebase) 821 return; 822 823 /* Make userspace gettimeofday spin until we're done. */ 824 ++vdso_data->tb_update_count; 825 smp_mb(); 826 827 /* XXX this assumes clock->shift == 22 */ 828 /* 4611686018 ~= 2^(20+64-22) / 1e9 */ 829 new_tb_to_xs = (u64) mult * 4611686018ULL; 830 new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC; 831 do_div(new_stamp_xsec, 1000000000); 832 new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC; 833 834 BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC); 835 /* this is tv_nsec / 1e9 as a 0.32 fraction */ 836 frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32; 837 838 /* 839 * tb_update_count is used to allow the userspace gettimeofday code 840 * to assure itself that it sees a consistent view of the tb_to_xs and 841 * stamp_xsec variables. It reads the tb_update_count, then reads 842 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If 843 * the two values of tb_update_count match and are even then the 844 * tb_to_xs and stamp_xsec values are consistent. If not, then it 845 * loops back and reads them again until this criteria is met. 846 * We expect the caller to have done the first increment of 847 * vdso_data->tb_update_count already. 848 */ 849 vdso_data->tb_orig_stamp = clock->cycle_last; 850 vdso_data->stamp_xsec = new_stamp_xsec; 851 vdso_data->tb_to_xs = new_tb_to_xs; 852 vdso_data->wtom_clock_sec = wtm->tv_sec; 853 vdso_data->wtom_clock_nsec = wtm->tv_nsec; 854 vdso_data->stamp_xtime = *wall_time; 855 vdso_data->stamp_sec_fraction = frac_sec; 856 smp_wmb(); 857 ++(vdso_data->tb_update_count); 858 } 859 860 void update_vsyscall_tz(void) 861 { 862 /* Make userspace gettimeofday spin until we're done. */ 863 ++vdso_data->tb_update_count; 864 smp_mb(); 865 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; 866 vdso_data->tz_dsttime = sys_tz.tz_dsttime; 867 smp_mb(); 868 ++vdso_data->tb_update_count; 869 } 870 871 static void __init clocksource_init(void) 872 { 873 struct clocksource *clock; 874 875 if (__USE_RTC()) 876 clock = &clocksource_rtc; 877 else 878 clock = &clocksource_timebase; 879 880 clock->mult = clocksource_hz2mult(tb_ticks_per_sec, clock->shift); 881 882 if (clocksource_register(clock)) { 883 printk(KERN_ERR "clocksource: %s is already registered\n", 884 clock->name); 885 return; 886 } 887 888 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 889 clock->name, clock->mult, clock->shift); 890 } 891 892 static int decrementer_set_next_event(unsigned long evt, 893 struct clock_event_device *dev) 894 { 895 __get_cpu_var(decrementers).next_tb = get_tb_or_rtc() + evt; 896 set_dec(evt); 897 return 0; 898 } 899 900 static void decrementer_set_mode(enum clock_event_mode mode, 901 struct clock_event_device *dev) 902 { 903 if (mode != CLOCK_EVT_MODE_ONESHOT) 904 decrementer_set_next_event(DECREMENTER_MAX, dev); 905 } 906 907 static inline uint64_t div_sc64(unsigned long ticks, unsigned long nsec, 908 int shift) 909 { 910 uint64_t tmp = ((uint64_t)ticks) << shift; 911 912 do_div(tmp, nsec); 913 return tmp; 914 } 915 916 static void __init setup_clockevent_multiplier(unsigned long hz) 917 { 918 u64 mult, shift = 32; 919 920 while (1) { 921 mult = div_sc64(hz, NSEC_PER_SEC, shift); 922 if (mult && (mult >> 32UL) == 0UL) 923 break; 924 925 shift--; 926 } 927 928 decrementer_clockevent.shift = shift; 929 decrementer_clockevent.mult = mult; 930 } 931 932 static void register_decrementer_clockevent(int cpu) 933 { 934 struct clock_event_device *dec = &per_cpu(decrementers, cpu).event; 935 936 *dec = decrementer_clockevent; 937 dec->cpumask = cpumask_of(cpu); 938 939 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 940 dec->name, dec->mult, dec->shift, cpu); 941 942 clockevents_register_device(dec); 943 } 944 945 static void __init init_decrementer_clockevent(void) 946 { 947 int cpu = smp_processor_id(); 948 949 setup_clockevent_multiplier(ppc_tb_freq); 950 decrementer_clockevent.max_delta_ns = 951 clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent); 952 decrementer_clockevent.min_delta_ns = 953 clockevent_delta2ns(2, &decrementer_clockevent); 954 955 register_decrementer_clockevent(cpu); 956 } 957 958 void secondary_cpu_time_init(void) 959 { 960 /* Start the decrementer on CPUs that have manual control 961 * such as BookE 962 */ 963 start_cpu_decrementer(); 964 965 /* FIME: Should make unrelatred change to move snapshot_timebase 966 * call here ! */ 967 register_decrementer_clockevent(smp_processor_id()); 968 } 969 970 /* This function is only called on the boot processor */ 971 void __init time_init(void) 972 { 973 struct div_result res; 974 u64 scale; 975 unsigned shift; 976 977 if (__USE_RTC()) { 978 /* 601 processor: dec counts down by 128 every 128ns */ 979 ppc_tb_freq = 1000000000; 980 } else { 981 /* Normal PowerPC with timebase register */ 982 ppc_md.calibrate_decr(); 983 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 984 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 985 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 986 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 987 } 988 989 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 990 tb_ticks_per_sec = ppc_tb_freq; 991 tb_ticks_per_usec = ppc_tb_freq / 1000000; 992 calc_cputime_factors(); 993 setup_cputime_one_jiffy(); 994 995 /* 996 * Compute scale factor for sched_clock. 997 * The calibrate_decr() function has set tb_ticks_per_sec, 998 * which is the timebase frequency. 999 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 1000 * the 128-bit result as a 64.64 fixed-point number. 1001 * We then shift that number right until it is less than 1.0, 1002 * giving us the scale factor and shift count to use in 1003 * sched_clock(). 1004 */ 1005 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 1006 scale = res.result_low; 1007 for (shift = 0; res.result_high != 0; ++shift) { 1008 scale = (scale >> 1) | (res.result_high << 63); 1009 res.result_high >>= 1; 1010 } 1011 tb_to_ns_scale = scale; 1012 tb_to_ns_shift = shift; 1013 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 1014 boot_tb = get_tb_or_rtc(); 1015 1016 /* If platform provided a timezone (pmac), we correct the time */ 1017 if (timezone_offset) { 1018 sys_tz.tz_minuteswest = -timezone_offset / 60; 1019 sys_tz.tz_dsttime = 0; 1020 } 1021 1022 vdso_data->tb_update_count = 0; 1023 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 1024 1025 /* Start the decrementer on CPUs that have manual control 1026 * such as BookE 1027 */ 1028 start_cpu_decrementer(); 1029 1030 /* Register the clocksource, if we're not running on iSeries */ 1031 if (!firmware_has_feature(FW_FEATURE_ISERIES)) 1032 clocksource_init(); 1033 1034 init_decrementer_clockevent(); 1035 } 1036 1037 1038 #define FEBRUARY 2 1039 #define STARTOFTIME 1970 1040 #define SECDAY 86400L 1041 #define SECYR (SECDAY * 365) 1042 #define leapyear(year) ((year) % 4 == 0 && \ 1043 ((year) % 100 != 0 || (year) % 400 == 0)) 1044 #define days_in_year(a) (leapyear(a) ? 366 : 365) 1045 #define days_in_month(a) (month_days[(a) - 1]) 1046 1047 static int month_days[12] = { 1048 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 1049 }; 1050 1051 /* 1052 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) 1053 */ 1054 void GregorianDay(struct rtc_time * tm) 1055 { 1056 int leapsToDate; 1057 int lastYear; 1058 int day; 1059 int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; 1060 1061 lastYear = tm->tm_year - 1; 1062 1063 /* 1064 * Number of leap corrections to apply up to end of last year 1065 */ 1066 leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400; 1067 1068 /* 1069 * This year is a leap year if it is divisible by 4 except when it is 1070 * divisible by 100 unless it is divisible by 400 1071 * 1072 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was 1073 */ 1074 day = tm->tm_mon > 2 && leapyear(tm->tm_year); 1075 1076 day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + 1077 tm->tm_mday; 1078 1079 tm->tm_wday = day % 7; 1080 } 1081 1082 void to_tm(int tim, struct rtc_time * tm) 1083 { 1084 register int i; 1085 register long hms, day; 1086 1087 day = tim / SECDAY; 1088 hms = tim % SECDAY; 1089 1090 /* Hours, minutes, seconds are easy */ 1091 tm->tm_hour = hms / 3600; 1092 tm->tm_min = (hms % 3600) / 60; 1093 tm->tm_sec = (hms % 3600) % 60; 1094 1095 /* Number of years in days */ 1096 for (i = STARTOFTIME; day >= days_in_year(i); i++) 1097 day -= days_in_year(i); 1098 tm->tm_year = i; 1099 1100 /* Number of months in days left */ 1101 if (leapyear(tm->tm_year)) 1102 days_in_month(FEBRUARY) = 29; 1103 for (i = 1; day >= days_in_month(i); i++) 1104 day -= days_in_month(i); 1105 days_in_month(FEBRUARY) = 28; 1106 tm->tm_mon = i; 1107 1108 /* Days are what is left over (+1) from all that. */ 1109 tm->tm_mday = day + 1; 1110 1111 /* 1112 * Determine the day of week 1113 */ 1114 GregorianDay(tm); 1115 } 1116 1117 /* 1118 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 1119 * result. 1120 */ 1121 void div128_by_32(u64 dividend_high, u64 dividend_low, 1122 unsigned divisor, struct div_result *dr) 1123 { 1124 unsigned long a, b, c, d; 1125 unsigned long w, x, y, z; 1126 u64 ra, rb, rc; 1127 1128 a = dividend_high >> 32; 1129 b = dividend_high & 0xffffffff; 1130 c = dividend_low >> 32; 1131 d = dividend_low & 0xffffffff; 1132 1133 w = a / divisor; 1134 ra = ((u64)(a - (w * divisor)) << 32) + b; 1135 1136 rb = ((u64) do_div(ra, divisor) << 32) + c; 1137 x = ra; 1138 1139 rc = ((u64) do_div(rb, divisor) << 32) + d; 1140 y = rb; 1141 1142 do_div(rc, divisor); 1143 z = rc; 1144 1145 dr->result_high = ((u64)w << 32) + x; 1146 dr->result_low = ((u64)y << 32) + z; 1147 1148 } 1149 1150 /* We don't need to calibrate delay, we use the CPU timebase for that */ 1151 void calibrate_delay(void) 1152 { 1153 /* Some generic code (such as spinlock debug) use loops_per_jiffy 1154 * as the number of __delay(1) in a jiffy, so make it so 1155 */ 1156 loops_per_jiffy = tb_ticks_per_jiffy; 1157 } 1158 1159 static int __init rtc_init(void) 1160 { 1161 struct platform_device *pdev; 1162 1163 if (!ppc_md.get_rtc_time) 1164 return -ENODEV; 1165 1166 pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0); 1167 if (IS_ERR(pdev)) 1168 return PTR_ERR(pdev); 1169 1170 return 0; 1171 } 1172 1173 module_init(rtc_init); 1174