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/perf_event.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 u64 tb_to_xs; 153 unsigned tb_to_us; 154 155 #define TICKLEN_SCALE NTP_SCALE_SHIFT 156 static u64 last_tick_len; /* units are ns / 2^TICKLEN_SCALE */ 157 static u64 ticklen_to_xs; /* 0.64 fraction */ 158 159 /* If last_tick_len corresponds to about 1/HZ seconds, then 160 last_tick_len << TICKLEN_SHIFT will be about 2^63. */ 161 #define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ) 162 163 DEFINE_SPINLOCK(rtc_lock); 164 EXPORT_SYMBOL_GPL(rtc_lock); 165 166 static u64 tb_to_ns_scale __read_mostly; 167 static unsigned tb_to_ns_shift __read_mostly; 168 static unsigned long boot_tb __read_mostly; 169 170 extern struct timezone sys_tz; 171 static long timezone_offset; 172 173 unsigned long ppc_proc_freq; 174 EXPORT_SYMBOL(ppc_proc_freq); 175 unsigned long ppc_tb_freq; 176 177 static u64 tb_last_jiffy __cacheline_aligned_in_smp; 178 static DEFINE_PER_CPU(u64, last_jiffy); 179 180 #ifdef CONFIG_VIRT_CPU_ACCOUNTING 181 /* 182 * Factors for converting from cputime_t (timebase ticks) to 183 * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds). 184 * These are all stored as 0.64 fixed-point binary fractions. 185 */ 186 u64 __cputime_jiffies_factor; 187 EXPORT_SYMBOL(__cputime_jiffies_factor); 188 u64 __cputime_msec_factor; 189 EXPORT_SYMBOL(__cputime_msec_factor); 190 u64 __cputime_sec_factor; 191 EXPORT_SYMBOL(__cputime_sec_factor); 192 u64 __cputime_clockt_factor; 193 EXPORT_SYMBOL(__cputime_clockt_factor); 194 DEFINE_PER_CPU(unsigned long, cputime_last_delta); 195 DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta); 196 197 cputime_t cputime_one_jiffy; 198 199 static void calc_cputime_factors(void) 200 { 201 struct div_result res; 202 203 div128_by_32(HZ, 0, tb_ticks_per_sec, &res); 204 __cputime_jiffies_factor = res.result_low; 205 div128_by_32(1000, 0, tb_ticks_per_sec, &res); 206 __cputime_msec_factor = res.result_low; 207 div128_by_32(1, 0, tb_ticks_per_sec, &res); 208 __cputime_sec_factor = res.result_low; 209 div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res); 210 __cputime_clockt_factor = res.result_low; 211 } 212 213 /* 214 * Read the PURR on systems that have it, otherwise the timebase. 215 */ 216 static u64 read_purr(void) 217 { 218 if (cpu_has_feature(CPU_FTR_PURR)) 219 return mfspr(SPRN_PURR); 220 return mftb(); 221 } 222 223 /* 224 * Read the SPURR on systems that have it, otherwise the purr 225 */ 226 static u64 read_spurr(u64 purr) 227 { 228 /* 229 * cpus without PURR won't have a SPURR 230 * We already know the former when we use this, so tell gcc 231 */ 232 if (cpu_has_feature(CPU_FTR_PURR) && cpu_has_feature(CPU_FTR_SPURR)) 233 return mfspr(SPRN_SPURR); 234 return purr; 235 } 236 237 /* 238 * Account time for a transition between system, hard irq 239 * or soft irq state. 240 */ 241 void account_system_vtime(struct task_struct *tsk) 242 { 243 u64 now, nowscaled, delta, deltascaled, sys_time; 244 unsigned long flags; 245 246 local_irq_save(flags); 247 now = read_purr(); 248 nowscaled = read_spurr(now); 249 delta = now - get_paca()->startpurr; 250 deltascaled = nowscaled - get_paca()->startspurr; 251 get_paca()->startpurr = now; 252 get_paca()->startspurr = nowscaled; 253 if (!in_interrupt()) { 254 /* deltascaled includes both user and system time. 255 * Hence scale it based on the purr ratio to estimate 256 * the system time */ 257 sys_time = get_paca()->system_time; 258 if (get_paca()->user_time) 259 deltascaled = deltascaled * sys_time / 260 (sys_time + get_paca()->user_time); 261 delta += sys_time; 262 get_paca()->system_time = 0; 263 } 264 if (in_irq() || idle_task(smp_processor_id()) != tsk) 265 account_system_time(tsk, 0, delta, deltascaled); 266 else 267 account_idle_time(delta); 268 per_cpu(cputime_last_delta, smp_processor_id()) = delta; 269 per_cpu(cputime_scaled_last_delta, smp_processor_id()) = deltascaled; 270 local_irq_restore(flags); 271 } 272 273 /* 274 * Transfer the user and system times accumulated in the paca 275 * by the exception entry and exit code to the generic process 276 * user and system time records. 277 * Must be called with interrupts disabled. 278 */ 279 void account_process_tick(struct task_struct *tsk, int user_tick) 280 { 281 cputime_t utime, utimescaled; 282 283 utime = get_paca()->user_time; 284 get_paca()->user_time = 0; 285 utimescaled = cputime_to_scaled(utime); 286 account_user_time(tsk, utime, utimescaled); 287 } 288 289 /* 290 * Stuff for accounting stolen time. 291 */ 292 struct cpu_purr_data { 293 int initialized; /* thread is running */ 294 u64 tb; /* last TB value read */ 295 u64 purr; /* last PURR value read */ 296 u64 spurr; /* last SPURR value read */ 297 }; 298 299 /* 300 * Each entry in the cpu_purr_data array is manipulated only by its 301 * "owner" cpu -- usually in the timer interrupt but also occasionally 302 * in process context for cpu online. As long as cpus do not touch 303 * each others' cpu_purr_data, disabling local interrupts is 304 * sufficient to serialize accesses. 305 */ 306 static DEFINE_PER_CPU(struct cpu_purr_data, cpu_purr_data); 307 308 static void snapshot_tb_and_purr(void *data) 309 { 310 unsigned long flags; 311 struct cpu_purr_data *p = &__get_cpu_var(cpu_purr_data); 312 313 local_irq_save(flags); 314 p->tb = get_tb_or_rtc(); 315 p->purr = mfspr(SPRN_PURR); 316 wmb(); 317 p->initialized = 1; 318 local_irq_restore(flags); 319 } 320 321 /* 322 * Called during boot when all cpus have come up. 323 */ 324 void snapshot_timebases(void) 325 { 326 if (!cpu_has_feature(CPU_FTR_PURR)) 327 return; 328 on_each_cpu(snapshot_tb_and_purr, NULL, 1); 329 } 330 331 /* 332 * Must be called with interrupts disabled. 333 */ 334 void calculate_steal_time(void) 335 { 336 u64 tb, purr; 337 s64 stolen; 338 struct cpu_purr_data *pme; 339 340 pme = &__get_cpu_var(cpu_purr_data); 341 if (!pme->initialized) 342 return; /* !CPU_FTR_PURR or early in early boot */ 343 tb = mftb(); 344 purr = mfspr(SPRN_PURR); 345 stolen = (tb - pme->tb) - (purr - pme->purr); 346 if (stolen > 0) { 347 if (idle_task(smp_processor_id()) != current) 348 account_steal_time(stolen); 349 else 350 account_idle_time(stolen); 351 } 352 pme->tb = tb; 353 pme->purr = purr; 354 } 355 356 #ifdef CONFIG_PPC_SPLPAR 357 /* 358 * Must be called before the cpu is added to the online map when 359 * a cpu is being brought up at runtime. 360 */ 361 static void snapshot_purr(void) 362 { 363 struct cpu_purr_data *pme; 364 unsigned long flags; 365 366 if (!cpu_has_feature(CPU_FTR_PURR)) 367 return; 368 local_irq_save(flags); 369 pme = &__get_cpu_var(cpu_purr_data); 370 pme->tb = mftb(); 371 pme->purr = mfspr(SPRN_PURR); 372 pme->initialized = 1; 373 local_irq_restore(flags); 374 } 375 376 #endif /* CONFIG_PPC_SPLPAR */ 377 378 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */ 379 #define calc_cputime_factors() 380 #define calculate_steal_time() do { } while (0) 381 #endif 382 383 #if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR)) 384 #define snapshot_purr() do { } while (0) 385 #endif 386 387 /* 388 * Called when a cpu comes up after the system has finished booting, 389 * i.e. as a result of a hotplug cpu action. 390 */ 391 void snapshot_timebase(void) 392 { 393 __get_cpu_var(last_jiffy) = get_tb_or_rtc(); 394 snapshot_purr(); 395 } 396 397 void __delay(unsigned long loops) 398 { 399 unsigned long start; 400 int diff; 401 402 if (__USE_RTC()) { 403 start = get_rtcl(); 404 do { 405 /* the RTCL register wraps at 1000000000 */ 406 diff = get_rtcl() - start; 407 if (diff < 0) 408 diff += 1000000000; 409 } while (diff < loops); 410 } else { 411 start = get_tbl(); 412 while (get_tbl() - start < loops) 413 HMT_low(); 414 HMT_medium(); 415 } 416 } 417 EXPORT_SYMBOL(__delay); 418 419 void udelay(unsigned long usecs) 420 { 421 __delay(tb_ticks_per_usec * usecs); 422 } 423 EXPORT_SYMBOL(udelay); 424 425 static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec, 426 u64 new_tb_to_xs) 427 { 428 /* 429 * tb_update_count is used to allow the userspace gettimeofday code 430 * to assure itself that it sees a consistent view of the tb_to_xs and 431 * stamp_xsec variables. It reads the tb_update_count, then reads 432 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If 433 * the two values of tb_update_count match and are even then the 434 * tb_to_xs and stamp_xsec values are consistent. If not, then it 435 * loops back and reads them again until this criteria is met. 436 * We expect the caller to have done the first increment of 437 * vdso_data->tb_update_count already. 438 */ 439 vdso_data->tb_orig_stamp = new_tb_stamp; 440 vdso_data->stamp_xsec = new_stamp_xsec; 441 vdso_data->tb_to_xs = new_tb_to_xs; 442 vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec; 443 vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec; 444 vdso_data->stamp_xtime = xtime; 445 smp_wmb(); 446 ++(vdso_data->tb_update_count); 447 } 448 449 #ifdef CONFIG_SMP 450 unsigned long profile_pc(struct pt_regs *regs) 451 { 452 unsigned long pc = instruction_pointer(regs); 453 454 if (in_lock_functions(pc)) 455 return regs->link; 456 457 return pc; 458 } 459 EXPORT_SYMBOL(profile_pc); 460 #endif 461 462 #ifdef CONFIG_PPC_ISERIES 463 464 /* 465 * This function recalibrates the timebase based on the 49-bit time-of-day 466 * value in the Titan chip. The Titan is much more accurate than the value 467 * returned by the service processor for the timebase frequency. 468 */ 469 470 static int __init iSeries_tb_recal(void) 471 { 472 struct div_result divres; 473 unsigned long titan, tb; 474 475 /* Make sure we only run on iSeries */ 476 if (!firmware_has_feature(FW_FEATURE_ISERIES)) 477 return -ENODEV; 478 479 tb = get_tb(); 480 titan = HvCallXm_loadTod(); 481 if ( iSeries_recal_titan ) { 482 unsigned long tb_ticks = tb - iSeries_recal_tb; 483 unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12; 484 unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec; 485 unsigned long new_tb_ticks_per_jiffy = 486 DIV_ROUND_CLOSEST(new_tb_ticks_per_sec, HZ); 487 long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy; 488 char sign = '+'; 489 /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */ 490 new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ; 491 492 if ( tick_diff < 0 ) { 493 tick_diff = -tick_diff; 494 sign = '-'; 495 } 496 if ( tick_diff ) { 497 if ( tick_diff < tb_ticks_per_jiffy/25 ) { 498 printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n", 499 new_tb_ticks_per_jiffy, sign, tick_diff ); 500 tb_ticks_per_jiffy = new_tb_ticks_per_jiffy; 501 tb_ticks_per_sec = new_tb_ticks_per_sec; 502 calc_cputime_factors(); 503 div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres ); 504 tb_to_xs = divres.result_low; 505 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 506 vdso_data->tb_to_xs = tb_to_xs; 507 setup_cputime_one_jiffy(); 508 } 509 else { 510 printk( "Titan recalibrate: FAILED (difference > 4 percent)\n" 511 " new tb_ticks_per_jiffy = %lu\n" 512 " old tb_ticks_per_jiffy = %lu\n", 513 new_tb_ticks_per_jiffy, tb_ticks_per_jiffy ); 514 } 515 } 516 } 517 iSeries_recal_titan = titan; 518 iSeries_recal_tb = tb; 519 520 /* Called here as now we know accurate values for the timebase */ 521 clocksource_init(); 522 return 0; 523 } 524 late_initcall(iSeries_tb_recal); 525 526 /* Called from platform early init */ 527 void __init iSeries_time_init_early(void) 528 { 529 iSeries_recal_tb = get_tb(); 530 iSeries_recal_titan = HvCallXm_loadTod(); 531 } 532 #endif /* CONFIG_PPC_ISERIES */ 533 534 #if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_PPC32) 535 DEFINE_PER_CPU(u8, perf_event_pending); 536 537 void set_perf_event_pending(void) 538 { 539 get_cpu_var(perf_event_pending) = 1; 540 set_dec(1); 541 put_cpu_var(perf_event_pending); 542 } 543 544 #define test_perf_event_pending() __get_cpu_var(perf_event_pending) 545 #define clear_perf_event_pending() __get_cpu_var(perf_event_pending) = 0 546 547 #else /* CONFIG_PERF_EVENTS && CONFIG_PPC32 */ 548 549 #define test_perf_event_pending() 0 550 #define clear_perf_event_pending() 551 552 #endif /* CONFIG_PERF_EVENTS && CONFIG_PPC32 */ 553 554 /* 555 * For iSeries shared processors, we have to let the hypervisor 556 * set the hardware decrementer. We set a virtual decrementer 557 * in the lppaca and call the hypervisor if the virtual 558 * decrementer is less than the current value in the hardware 559 * decrementer. (almost always the new decrementer value will 560 * be greater than the current hardware decementer so the hypervisor 561 * call will not be needed) 562 */ 563 564 /* 565 * timer_interrupt - gets called when the decrementer overflows, 566 * with interrupts disabled. 567 */ 568 void timer_interrupt(struct pt_regs * regs) 569 { 570 struct pt_regs *old_regs; 571 struct decrementer_clock *decrementer = &__get_cpu_var(decrementers); 572 struct clock_event_device *evt = &decrementer->event; 573 u64 now; 574 575 trace_timer_interrupt_entry(regs); 576 577 /* Ensure a positive value is written to the decrementer, or else 578 * some CPUs will continuue to take decrementer exceptions */ 579 set_dec(DECREMENTER_MAX); 580 581 #ifdef CONFIG_PPC32 582 if (test_perf_event_pending()) { 583 clear_perf_event_pending(); 584 perf_event_do_pending(); 585 } 586 if (atomic_read(&ppc_n_lost_interrupts) != 0) 587 do_IRQ(regs); 588 #endif 589 590 now = get_tb_or_rtc(); 591 if (now < decrementer->next_tb) { 592 /* not time for this event yet */ 593 now = decrementer->next_tb - now; 594 if (now <= DECREMENTER_MAX) 595 set_dec((int)now); 596 trace_timer_interrupt_exit(regs); 597 return; 598 } 599 old_regs = set_irq_regs(regs); 600 irq_enter(); 601 602 calculate_steal_time(); 603 604 #ifdef CONFIG_PPC_ISERIES 605 if (firmware_has_feature(FW_FEATURE_ISERIES)) 606 get_lppaca()->int_dword.fields.decr_int = 0; 607 #endif 608 609 if (evt->event_handler) 610 evt->event_handler(evt); 611 612 #ifdef CONFIG_PPC_ISERIES 613 if (firmware_has_feature(FW_FEATURE_ISERIES) && hvlpevent_is_pending()) 614 process_hvlpevents(); 615 #endif 616 617 #ifdef CONFIG_PPC64 618 /* collect purr register values often, for accurate calculations */ 619 if (firmware_has_feature(FW_FEATURE_SPLPAR)) { 620 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); 621 cu->current_tb = mfspr(SPRN_PURR); 622 } 623 #endif 624 625 irq_exit(); 626 set_irq_regs(old_regs); 627 628 trace_timer_interrupt_exit(regs); 629 } 630 631 void wakeup_decrementer(void) 632 { 633 unsigned long ticks; 634 635 /* 636 * The timebase gets saved on sleep and restored on wakeup, 637 * so all we need to do is to reset the decrementer. 638 */ 639 ticks = tb_ticks_since(__get_cpu_var(last_jiffy)); 640 if (ticks < tb_ticks_per_jiffy) 641 ticks = tb_ticks_per_jiffy - ticks; 642 else 643 ticks = 1; 644 set_dec(ticks); 645 } 646 647 #ifdef CONFIG_SUSPEND 648 void generic_suspend_disable_irqs(void) 649 { 650 preempt_disable(); 651 652 /* Disable the decrementer, so that it doesn't interfere 653 * with suspending. 654 */ 655 656 set_dec(0x7fffffff); 657 local_irq_disable(); 658 set_dec(0x7fffffff); 659 } 660 661 void generic_suspend_enable_irqs(void) 662 { 663 wakeup_decrementer(); 664 665 local_irq_enable(); 666 preempt_enable(); 667 } 668 669 /* Overrides the weak version in kernel/power/main.c */ 670 void arch_suspend_disable_irqs(void) 671 { 672 if (ppc_md.suspend_disable_irqs) 673 ppc_md.suspend_disable_irqs(); 674 generic_suspend_disable_irqs(); 675 } 676 677 /* Overrides the weak version in kernel/power/main.c */ 678 void arch_suspend_enable_irqs(void) 679 { 680 generic_suspend_enable_irqs(); 681 if (ppc_md.suspend_enable_irqs) 682 ppc_md.suspend_enable_irqs(); 683 } 684 #endif 685 686 #ifdef CONFIG_SMP 687 void __init smp_space_timers(unsigned int max_cpus) 688 { 689 int i; 690 u64 previous_tb = per_cpu(last_jiffy, boot_cpuid); 691 692 /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */ 693 previous_tb -= tb_ticks_per_jiffy; 694 695 for_each_possible_cpu(i) { 696 if (i == boot_cpuid) 697 continue; 698 per_cpu(last_jiffy, i) = previous_tb; 699 } 700 } 701 #endif 702 703 /* 704 * Scheduler clock - returns current time in nanosec units. 705 * 706 * Note: mulhdu(a, b) (multiply high double unsigned) returns 707 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 708 * are 64-bit unsigned numbers. 709 */ 710 unsigned long long sched_clock(void) 711 { 712 if (__USE_RTC()) 713 return get_rtc(); 714 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 715 } 716 717 static int __init get_freq(char *name, int cells, unsigned long *val) 718 { 719 struct device_node *cpu; 720 const unsigned int *fp; 721 int found = 0; 722 723 /* The cpu node should have timebase and clock frequency properties */ 724 cpu = of_find_node_by_type(NULL, "cpu"); 725 726 if (cpu) { 727 fp = of_get_property(cpu, name, NULL); 728 if (fp) { 729 found = 1; 730 *val = of_read_ulong(fp, cells); 731 } 732 733 of_node_put(cpu); 734 } 735 736 return found; 737 } 738 739 /* should become __cpuinit when secondary_cpu_time_init also is */ 740 void start_cpu_decrementer(void) 741 { 742 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) 743 /* Clear any pending timer interrupts */ 744 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 745 746 /* Enable decrementer interrupt */ 747 mtspr(SPRN_TCR, TCR_DIE); 748 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */ 749 } 750 751 void __init generic_calibrate_decr(void) 752 { 753 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 754 755 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 756 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 757 758 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 759 "(not found)\n"); 760 } 761 762 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 763 764 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 765 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 766 767 printk(KERN_ERR "WARNING: Estimating processor frequency " 768 "(not found)\n"); 769 } 770 } 771 772 int update_persistent_clock(struct timespec now) 773 { 774 struct rtc_time tm; 775 776 if (!ppc_md.set_rtc_time) 777 return 0; 778 779 to_tm(now.tv_sec + 1 + timezone_offset, &tm); 780 tm.tm_year -= 1900; 781 tm.tm_mon -= 1; 782 783 return ppc_md.set_rtc_time(&tm); 784 } 785 786 static void __read_persistent_clock(struct timespec *ts) 787 { 788 struct rtc_time tm; 789 static int first = 1; 790 791 ts->tv_nsec = 0; 792 /* XXX this is a litle fragile but will work okay in the short term */ 793 if (first) { 794 first = 0; 795 if (ppc_md.time_init) 796 timezone_offset = ppc_md.time_init(); 797 798 /* get_boot_time() isn't guaranteed to be safe to call late */ 799 if (ppc_md.get_boot_time) { 800 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 801 return; 802 } 803 } 804 if (!ppc_md.get_rtc_time) { 805 ts->tv_sec = 0; 806 return; 807 } 808 ppc_md.get_rtc_time(&tm); 809 810 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, 811 tm.tm_hour, tm.tm_min, tm.tm_sec); 812 } 813 814 void read_persistent_clock(struct timespec *ts) 815 { 816 __read_persistent_clock(ts); 817 818 /* Sanitize it in case real time clock is set below EPOCH */ 819 if (ts->tv_sec < 0) { 820 ts->tv_sec = 0; 821 ts->tv_nsec = 0; 822 } 823 824 } 825 826 /* clocksource code */ 827 static cycle_t rtc_read(struct clocksource *cs) 828 { 829 return (cycle_t)get_rtc(); 830 } 831 832 static cycle_t timebase_read(struct clocksource *cs) 833 { 834 return (cycle_t)get_tb(); 835 } 836 837 void update_vsyscall(struct timespec *wall_time, struct clocksource *clock, 838 u32 mult) 839 { 840 u64 t2x, stamp_xsec; 841 842 if (clock != &clocksource_timebase) 843 return; 844 845 /* Make userspace gettimeofday spin until we're done. */ 846 ++vdso_data->tb_update_count; 847 smp_mb(); 848 849 /* XXX this assumes clock->shift == 22 */ 850 /* 4611686018 ~= 2^(20+64-22) / 1e9 */ 851 t2x = (u64) mult * 4611686018ULL; 852 stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC; 853 do_div(stamp_xsec, 1000000000); 854 stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC; 855 update_gtod(clock->cycle_last, stamp_xsec, t2x); 856 } 857 858 void update_vsyscall_tz(void) 859 { 860 /* Make userspace gettimeofday spin until we're done. */ 861 ++vdso_data->tb_update_count; 862 smp_mb(); 863 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; 864 vdso_data->tz_dsttime = sys_tz.tz_dsttime; 865 smp_mb(); 866 ++vdso_data->tb_update_count; 867 } 868 869 static void __init clocksource_init(void) 870 { 871 struct clocksource *clock; 872 873 if (__USE_RTC()) 874 clock = &clocksource_rtc; 875 else 876 clock = &clocksource_timebase; 877 878 clock->mult = clocksource_hz2mult(tb_ticks_per_sec, clock->shift); 879 880 if (clocksource_register(clock)) { 881 printk(KERN_ERR "clocksource: %s is already registered\n", 882 clock->name); 883 return; 884 } 885 886 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 887 clock->name, clock->mult, clock->shift); 888 } 889 890 static int decrementer_set_next_event(unsigned long evt, 891 struct clock_event_device *dev) 892 { 893 __get_cpu_var(decrementers).next_tb = get_tb_or_rtc() + evt; 894 set_dec(evt); 895 return 0; 896 } 897 898 static void decrementer_set_mode(enum clock_event_mode mode, 899 struct clock_event_device *dev) 900 { 901 if (mode != CLOCK_EVT_MODE_ONESHOT) 902 decrementer_set_next_event(DECREMENTER_MAX, dev); 903 } 904 905 static void __init setup_clockevent_multiplier(unsigned long hz) 906 { 907 u64 mult, shift = 32; 908 909 while (1) { 910 mult = div_sc(hz, NSEC_PER_SEC, shift); 911 if (mult && (mult >> 32UL) == 0UL) 912 break; 913 914 shift--; 915 } 916 917 decrementer_clockevent.shift = shift; 918 decrementer_clockevent.mult = mult; 919 } 920 921 static void register_decrementer_clockevent(int cpu) 922 { 923 struct clock_event_device *dec = &per_cpu(decrementers, cpu).event; 924 925 *dec = decrementer_clockevent; 926 dec->cpumask = cpumask_of(cpu); 927 928 printk(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 929 dec->name, dec->mult, dec->shift, cpu); 930 931 clockevents_register_device(dec); 932 } 933 934 static void __init init_decrementer_clockevent(void) 935 { 936 int cpu = smp_processor_id(); 937 938 setup_clockevent_multiplier(ppc_tb_freq); 939 decrementer_clockevent.max_delta_ns = 940 clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent); 941 decrementer_clockevent.min_delta_ns = 942 clockevent_delta2ns(2, &decrementer_clockevent); 943 944 register_decrementer_clockevent(cpu); 945 } 946 947 void secondary_cpu_time_init(void) 948 { 949 /* Start the decrementer on CPUs that have manual control 950 * such as BookE 951 */ 952 start_cpu_decrementer(); 953 954 /* FIME: Should make unrelatred change to move snapshot_timebase 955 * call here ! */ 956 register_decrementer_clockevent(smp_processor_id()); 957 } 958 959 /* This function is only called on the boot processor */ 960 void __init time_init(void) 961 { 962 unsigned long flags; 963 struct div_result res; 964 u64 scale, x; 965 unsigned shift; 966 967 if (__USE_RTC()) { 968 /* 601 processor: dec counts down by 128 every 128ns */ 969 ppc_tb_freq = 1000000000; 970 tb_last_jiffy = get_rtcl(); 971 } else { 972 /* Normal PowerPC with timebase register */ 973 ppc_md.calibrate_decr(); 974 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 975 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 976 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 977 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 978 tb_last_jiffy = get_tb(); 979 } 980 981 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 982 tb_ticks_per_sec = ppc_tb_freq; 983 tb_ticks_per_usec = ppc_tb_freq / 1000000; 984 tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000); 985 calc_cputime_factors(); 986 setup_cputime_one_jiffy(); 987 988 /* 989 * Calculate the length of each tick in ns. It will not be 990 * exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ. 991 * We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq, 992 * rounded up. 993 */ 994 x = (u64) NSEC_PER_SEC * tb_ticks_per_jiffy + ppc_tb_freq - 1; 995 do_div(x, ppc_tb_freq); 996 tick_nsec = x; 997 last_tick_len = x << TICKLEN_SCALE; 998 999 /* 1000 * Compute ticklen_to_xs, which is a factor which gets multiplied 1001 * by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value. 1002 * It is computed as: 1003 * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9) 1004 * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT 1005 * which turns out to be N = 51 - SHIFT_HZ. 1006 * This gives the result as a 0.64 fixed-point fraction. 1007 * That value is reduced by an offset amounting to 1 xsec per 1008 * 2^31 timebase ticks to avoid problems with time going backwards 1009 * by 1 xsec when we do timer_recalc_offset due to losing the 1010 * fractional xsec. That offset is equal to ppc_tb_freq/2^51 1011 * since there are 2^20 xsec in a second. 1012 */ 1013 div128_by_32((1ULL << 51) - ppc_tb_freq, 0, 1014 tb_ticks_per_jiffy << SHIFT_HZ, &res); 1015 div128_by_32(res.result_high, res.result_low, NSEC_PER_SEC, &res); 1016 ticklen_to_xs = res.result_low; 1017 1018 /* Compute tb_to_xs from tick_nsec */ 1019 tb_to_xs = mulhdu(last_tick_len << TICKLEN_SHIFT, ticklen_to_xs); 1020 1021 /* 1022 * Compute scale factor for sched_clock. 1023 * The calibrate_decr() function has set tb_ticks_per_sec, 1024 * which is the timebase frequency. 1025 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 1026 * the 128-bit result as a 64.64 fixed-point number. 1027 * We then shift that number right until it is less than 1.0, 1028 * giving us the scale factor and shift count to use in 1029 * sched_clock(). 1030 */ 1031 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 1032 scale = res.result_low; 1033 for (shift = 0; res.result_high != 0; ++shift) { 1034 scale = (scale >> 1) | (res.result_high << 63); 1035 res.result_high >>= 1; 1036 } 1037 tb_to_ns_scale = scale; 1038 tb_to_ns_shift = shift; 1039 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 1040 boot_tb = get_tb_or_rtc(); 1041 1042 write_seqlock_irqsave(&xtime_lock, flags); 1043 1044 /* If platform provided a timezone (pmac), we correct the time */ 1045 if (timezone_offset) { 1046 sys_tz.tz_minuteswest = -timezone_offset / 60; 1047 sys_tz.tz_dsttime = 0; 1048 } 1049 1050 vdso_data->tb_orig_stamp = tb_last_jiffy; 1051 vdso_data->tb_update_count = 0; 1052 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 1053 vdso_data->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC; 1054 vdso_data->tb_to_xs = tb_to_xs; 1055 1056 write_sequnlock_irqrestore(&xtime_lock, flags); 1057 1058 /* Start the decrementer on CPUs that have manual control 1059 * such as BookE 1060 */ 1061 start_cpu_decrementer(); 1062 1063 /* Register the clocksource, if we're not running on iSeries */ 1064 if (!firmware_has_feature(FW_FEATURE_ISERIES)) 1065 clocksource_init(); 1066 1067 init_decrementer_clockevent(); 1068 } 1069 1070 1071 #define FEBRUARY 2 1072 #define STARTOFTIME 1970 1073 #define SECDAY 86400L 1074 #define SECYR (SECDAY * 365) 1075 #define leapyear(year) ((year) % 4 == 0 && \ 1076 ((year) % 100 != 0 || (year) % 400 == 0)) 1077 #define days_in_year(a) (leapyear(a) ? 366 : 365) 1078 #define days_in_month(a) (month_days[(a) - 1]) 1079 1080 static int month_days[12] = { 1081 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 1082 }; 1083 1084 /* 1085 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) 1086 */ 1087 void GregorianDay(struct rtc_time * tm) 1088 { 1089 int leapsToDate; 1090 int lastYear; 1091 int day; 1092 int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; 1093 1094 lastYear = tm->tm_year - 1; 1095 1096 /* 1097 * Number of leap corrections to apply up to end of last year 1098 */ 1099 leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400; 1100 1101 /* 1102 * This year is a leap year if it is divisible by 4 except when it is 1103 * divisible by 100 unless it is divisible by 400 1104 * 1105 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was 1106 */ 1107 day = tm->tm_mon > 2 && leapyear(tm->tm_year); 1108 1109 day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + 1110 tm->tm_mday; 1111 1112 tm->tm_wday = day % 7; 1113 } 1114 1115 void to_tm(int tim, struct rtc_time * tm) 1116 { 1117 register int i; 1118 register long hms, day; 1119 1120 day = tim / SECDAY; 1121 hms = tim % SECDAY; 1122 1123 /* Hours, minutes, seconds are easy */ 1124 tm->tm_hour = hms / 3600; 1125 tm->tm_min = (hms % 3600) / 60; 1126 tm->tm_sec = (hms % 3600) % 60; 1127 1128 /* Number of years in days */ 1129 for (i = STARTOFTIME; day >= days_in_year(i); i++) 1130 day -= days_in_year(i); 1131 tm->tm_year = i; 1132 1133 /* Number of months in days left */ 1134 if (leapyear(tm->tm_year)) 1135 days_in_month(FEBRUARY) = 29; 1136 for (i = 1; day >= days_in_month(i); i++) 1137 day -= days_in_month(i); 1138 days_in_month(FEBRUARY) = 28; 1139 tm->tm_mon = i; 1140 1141 /* Days are what is left over (+1) from all that. */ 1142 tm->tm_mday = day + 1; 1143 1144 /* 1145 * Determine the day of week 1146 */ 1147 GregorianDay(tm); 1148 } 1149 1150 /* Auxiliary function to compute scaling factors */ 1151 /* Actually the choice of a timebase running at 1/4 the of the bus 1152 * frequency giving resolution of a few tens of nanoseconds is quite nice. 1153 * It makes this computation very precise (27-28 bits typically) which 1154 * is optimistic considering the stability of most processor clock 1155 * oscillators and the precision with which the timebase frequency 1156 * is measured but does not harm. 1157 */ 1158 unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale) 1159 { 1160 unsigned mlt=0, tmp, err; 1161 /* No concern for performance, it's done once: use a stupid 1162 * but safe and compact method to find the multiplier. 1163 */ 1164 1165 for (tmp = 1U<<31; tmp != 0; tmp >>= 1) { 1166 if (mulhwu(inscale, mlt|tmp) < outscale) 1167 mlt |= tmp; 1168 } 1169 1170 /* We might still be off by 1 for the best approximation. 1171 * A side effect of this is that if outscale is too large 1172 * the returned value will be zero. 1173 * Many corner cases have been checked and seem to work, 1174 * some might have been forgotten in the test however. 1175 */ 1176 1177 err = inscale * (mlt+1); 1178 if (err <= inscale/2) 1179 mlt++; 1180 return mlt; 1181 } 1182 1183 /* 1184 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 1185 * result. 1186 */ 1187 void div128_by_32(u64 dividend_high, u64 dividend_low, 1188 unsigned divisor, struct div_result *dr) 1189 { 1190 unsigned long a, b, c, d; 1191 unsigned long w, x, y, z; 1192 u64 ra, rb, rc; 1193 1194 a = dividend_high >> 32; 1195 b = dividend_high & 0xffffffff; 1196 c = dividend_low >> 32; 1197 d = dividend_low & 0xffffffff; 1198 1199 w = a / divisor; 1200 ra = ((u64)(a - (w * divisor)) << 32) + b; 1201 1202 rb = ((u64) do_div(ra, divisor) << 32) + c; 1203 x = ra; 1204 1205 rc = ((u64) do_div(rb, divisor) << 32) + d; 1206 y = rb; 1207 1208 do_div(rc, divisor); 1209 z = rc; 1210 1211 dr->result_high = ((u64)w << 32) + x; 1212 dr->result_low = ((u64)y << 32) + z; 1213 1214 } 1215 1216 /* We don't need to calibrate delay, we use the CPU timebase for that */ 1217 void calibrate_delay(void) 1218 { 1219 /* Some generic code (such as spinlock debug) use loops_per_jiffy 1220 * as the number of __delay(1) in a jiffy, so make it so 1221 */ 1222 loops_per_jiffy = tb_ticks_per_jiffy; 1223 } 1224 1225 static int __init rtc_init(void) 1226 { 1227 struct platform_device *pdev; 1228 1229 if (!ppc_md.get_rtc_time) 1230 return -ENODEV; 1231 1232 pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0); 1233 if (IS_ERR(pdev)) 1234 return PTR_ERR(pdev); 1235 1236 return 0; 1237 } 1238 1239 module_init(rtc_init); 1240