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 EXPORT_SYMBOL_GPL(account_system_vtime); 273 274 /* 275 * Transfer the user and system times accumulated in the paca 276 * by the exception entry and exit code to the generic process 277 * user and system time records. 278 * Must be called with interrupts disabled. 279 */ 280 void account_process_tick(struct task_struct *tsk, int user_tick) 281 { 282 cputime_t utime, utimescaled; 283 284 utime = get_paca()->user_time; 285 get_paca()->user_time = 0; 286 utimescaled = cputime_to_scaled(utime); 287 account_user_time(tsk, utime, utimescaled); 288 } 289 290 /* 291 * Stuff for accounting stolen time. 292 */ 293 struct cpu_purr_data { 294 int initialized; /* thread is running */ 295 u64 tb; /* last TB value read */ 296 u64 purr; /* last PURR value read */ 297 u64 spurr; /* last SPURR value read */ 298 }; 299 300 /* 301 * Each entry in the cpu_purr_data array is manipulated only by its 302 * "owner" cpu -- usually in the timer interrupt but also occasionally 303 * in process context for cpu online. As long as cpus do not touch 304 * each others' cpu_purr_data, disabling local interrupts is 305 * sufficient to serialize accesses. 306 */ 307 static DEFINE_PER_CPU(struct cpu_purr_data, cpu_purr_data); 308 309 static void snapshot_tb_and_purr(void *data) 310 { 311 unsigned long flags; 312 struct cpu_purr_data *p = &__get_cpu_var(cpu_purr_data); 313 314 local_irq_save(flags); 315 p->tb = get_tb_or_rtc(); 316 p->purr = mfspr(SPRN_PURR); 317 wmb(); 318 p->initialized = 1; 319 local_irq_restore(flags); 320 } 321 322 /* 323 * Called during boot when all cpus have come up. 324 */ 325 void snapshot_timebases(void) 326 { 327 if (!cpu_has_feature(CPU_FTR_PURR)) 328 return; 329 on_each_cpu(snapshot_tb_and_purr, NULL, 1); 330 } 331 332 /* 333 * Must be called with interrupts disabled. 334 */ 335 void calculate_steal_time(void) 336 { 337 u64 tb, purr; 338 s64 stolen; 339 struct cpu_purr_data *pme; 340 341 pme = &__get_cpu_var(cpu_purr_data); 342 if (!pme->initialized) 343 return; /* !CPU_FTR_PURR or early in early boot */ 344 tb = mftb(); 345 purr = mfspr(SPRN_PURR); 346 stolen = (tb - pme->tb) - (purr - pme->purr); 347 if (stolen > 0) { 348 if (idle_task(smp_processor_id()) != current) 349 account_steal_time(stolen); 350 else 351 account_idle_time(stolen); 352 } 353 pme->tb = tb; 354 pme->purr = purr; 355 } 356 357 #ifdef CONFIG_PPC_SPLPAR 358 /* 359 * Must be called before the cpu is added to the online map when 360 * a cpu is being brought up at runtime. 361 */ 362 static void snapshot_purr(void) 363 { 364 struct cpu_purr_data *pme; 365 unsigned long flags; 366 367 if (!cpu_has_feature(CPU_FTR_PURR)) 368 return; 369 local_irq_save(flags); 370 pme = &__get_cpu_var(cpu_purr_data); 371 pme->tb = mftb(); 372 pme->purr = mfspr(SPRN_PURR); 373 pme->initialized = 1; 374 local_irq_restore(flags); 375 } 376 377 #endif /* CONFIG_PPC_SPLPAR */ 378 379 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */ 380 #define calc_cputime_factors() 381 #define calculate_steal_time() do { } while (0) 382 #endif 383 384 #if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR)) 385 #define snapshot_purr() do { } while (0) 386 #endif 387 388 /* 389 * Called when a cpu comes up after the system has finished booting, 390 * i.e. as a result of a hotplug cpu action. 391 */ 392 void snapshot_timebase(void) 393 { 394 __get_cpu_var(last_jiffy) = get_tb_or_rtc(); 395 snapshot_purr(); 396 } 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 static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec, 427 u64 new_tb_to_xs) 428 { 429 /* 430 * tb_update_count is used to allow the userspace gettimeofday code 431 * to assure itself that it sees a consistent view of the tb_to_xs and 432 * stamp_xsec variables. It reads the tb_update_count, then reads 433 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If 434 * the two values of tb_update_count match and are even then the 435 * tb_to_xs and stamp_xsec values are consistent. If not, then it 436 * loops back and reads them again until this criteria is met. 437 * We expect the caller to have done the first increment of 438 * vdso_data->tb_update_count already. 439 */ 440 vdso_data->tb_orig_stamp = new_tb_stamp; 441 vdso_data->stamp_xsec = new_stamp_xsec; 442 vdso_data->tb_to_xs = new_tb_to_xs; 443 vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec; 444 vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec; 445 vdso_data->stamp_xtime = xtime; 446 smp_wmb(); 447 ++(vdso_data->tb_update_count); 448 } 449 450 #ifdef CONFIG_SMP 451 unsigned long profile_pc(struct pt_regs *regs) 452 { 453 unsigned long pc = instruction_pointer(regs); 454 455 if (in_lock_functions(pc)) 456 return regs->link; 457 458 return pc; 459 } 460 EXPORT_SYMBOL(profile_pc); 461 #endif 462 463 #ifdef CONFIG_PPC_ISERIES 464 465 /* 466 * This function recalibrates the timebase based on the 49-bit time-of-day 467 * value in the Titan chip. The Titan is much more accurate than the value 468 * returned by the service processor for the timebase frequency. 469 */ 470 471 static int __init iSeries_tb_recal(void) 472 { 473 struct div_result divres; 474 unsigned long titan, tb; 475 476 /* Make sure we only run on iSeries */ 477 if (!firmware_has_feature(FW_FEATURE_ISERIES)) 478 return -ENODEV; 479 480 tb = get_tb(); 481 titan = HvCallXm_loadTod(); 482 if ( iSeries_recal_titan ) { 483 unsigned long tb_ticks = tb - iSeries_recal_tb; 484 unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12; 485 unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec; 486 unsigned long new_tb_ticks_per_jiffy = 487 DIV_ROUND_CLOSEST(new_tb_ticks_per_sec, HZ); 488 long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy; 489 char sign = '+'; 490 /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */ 491 new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ; 492 493 if ( tick_diff < 0 ) { 494 tick_diff = -tick_diff; 495 sign = '-'; 496 } 497 if ( tick_diff ) { 498 if ( tick_diff < tb_ticks_per_jiffy/25 ) { 499 printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n", 500 new_tb_ticks_per_jiffy, sign, tick_diff ); 501 tb_ticks_per_jiffy = new_tb_ticks_per_jiffy; 502 tb_ticks_per_sec = new_tb_ticks_per_sec; 503 calc_cputime_factors(); 504 div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres ); 505 tb_to_xs = divres.result_low; 506 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 507 vdso_data->tb_to_xs = tb_to_xs; 508 setup_cputime_one_jiffy(); 509 } 510 else { 511 printk( "Titan recalibrate: FAILED (difference > 4 percent)\n" 512 " new tb_ticks_per_jiffy = %lu\n" 513 " old tb_ticks_per_jiffy = %lu\n", 514 new_tb_ticks_per_jiffy, tb_ticks_per_jiffy ); 515 } 516 } 517 } 518 iSeries_recal_titan = titan; 519 iSeries_recal_tb = tb; 520 521 /* Called here as now we know accurate values for the timebase */ 522 clocksource_init(); 523 return 0; 524 } 525 late_initcall(iSeries_tb_recal); 526 527 /* Called from platform early init */ 528 void __init iSeries_time_init_early(void) 529 { 530 iSeries_recal_tb = get_tb(); 531 iSeries_recal_titan = HvCallXm_loadTod(); 532 } 533 #endif /* CONFIG_PPC_ISERIES */ 534 535 #if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_PPC32) 536 DEFINE_PER_CPU(u8, perf_event_pending); 537 538 void set_perf_event_pending(void) 539 { 540 get_cpu_var(perf_event_pending) = 1; 541 set_dec(1); 542 put_cpu_var(perf_event_pending); 543 } 544 545 #define test_perf_event_pending() __get_cpu_var(perf_event_pending) 546 #define clear_perf_event_pending() __get_cpu_var(perf_event_pending) = 0 547 548 #else /* CONFIG_PERF_EVENTS && CONFIG_PPC32 */ 549 550 #define test_perf_event_pending() 0 551 #define clear_perf_event_pending() 552 553 #endif /* CONFIG_PERF_EVENTS && CONFIG_PPC32 */ 554 555 /* 556 * For iSeries shared processors, we have to let the hypervisor 557 * set the hardware decrementer. We set a virtual decrementer 558 * in the lppaca and call the hypervisor if the virtual 559 * decrementer is less than the current value in the hardware 560 * decrementer. (almost always the new decrementer value will 561 * be greater than the current hardware decementer so the hypervisor 562 * call will not be needed) 563 */ 564 565 /* 566 * timer_interrupt - gets called when the decrementer overflows, 567 * with interrupts disabled. 568 */ 569 void timer_interrupt(struct pt_regs * regs) 570 { 571 struct pt_regs *old_regs; 572 struct decrementer_clock *decrementer = &__get_cpu_var(decrementers); 573 struct clock_event_device *evt = &decrementer->event; 574 u64 now; 575 576 trace_timer_interrupt_entry(regs); 577 578 /* Ensure a positive value is written to the decrementer, or else 579 * some CPUs will continuue to take decrementer exceptions */ 580 set_dec(DECREMENTER_MAX); 581 582 #ifdef CONFIG_PPC32 583 if (test_perf_event_pending()) { 584 clear_perf_event_pending(); 585 perf_event_do_pending(); 586 } 587 if (atomic_read(&ppc_n_lost_interrupts) != 0) 588 do_IRQ(regs); 589 #endif 590 591 now = get_tb_or_rtc(); 592 if (now < decrementer->next_tb) { 593 /* not time for this event yet */ 594 now = decrementer->next_tb - now; 595 if (now <= DECREMENTER_MAX) 596 set_dec((int)now); 597 trace_timer_interrupt_exit(regs); 598 return; 599 } 600 old_regs = set_irq_regs(regs); 601 irq_enter(); 602 603 calculate_steal_time(); 604 605 #ifdef CONFIG_PPC_ISERIES 606 if (firmware_has_feature(FW_FEATURE_ISERIES)) 607 get_lppaca()->int_dword.fields.decr_int = 0; 608 #endif 609 610 if (evt->event_handler) 611 evt->event_handler(evt); 612 613 #ifdef CONFIG_PPC_ISERIES 614 if (firmware_has_feature(FW_FEATURE_ISERIES) && hvlpevent_is_pending()) 615 process_hvlpevents(); 616 #endif 617 618 #ifdef CONFIG_PPC64 619 /* collect purr register values often, for accurate calculations */ 620 if (firmware_has_feature(FW_FEATURE_SPLPAR)) { 621 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); 622 cu->current_tb = mfspr(SPRN_PURR); 623 } 624 #endif 625 626 irq_exit(); 627 set_irq_regs(old_regs); 628 629 trace_timer_interrupt_exit(regs); 630 } 631 632 void wakeup_decrementer(void) 633 { 634 unsigned long ticks; 635 636 /* 637 * The timebase gets saved on sleep and restored on wakeup, 638 * so all we need to do is to reset the decrementer. 639 */ 640 ticks = tb_ticks_since(__get_cpu_var(last_jiffy)); 641 if (ticks < tb_ticks_per_jiffy) 642 ticks = tb_ticks_per_jiffy - ticks; 643 else 644 ticks = 1; 645 set_dec(ticks); 646 } 647 648 #ifdef CONFIG_SUSPEND 649 void generic_suspend_disable_irqs(void) 650 { 651 preempt_disable(); 652 653 /* Disable the decrementer, so that it doesn't interfere 654 * with suspending. 655 */ 656 657 set_dec(0x7fffffff); 658 local_irq_disable(); 659 set_dec(0x7fffffff); 660 } 661 662 void generic_suspend_enable_irqs(void) 663 { 664 wakeup_decrementer(); 665 666 local_irq_enable(); 667 preempt_enable(); 668 } 669 670 /* Overrides the weak version in kernel/power/main.c */ 671 void arch_suspend_disable_irqs(void) 672 { 673 if (ppc_md.suspend_disable_irqs) 674 ppc_md.suspend_disable_irqs(); 675 generic_suspend_disable_irqs(); 676 } 677 678 /* Overrides the weak version in kernel/power/main.c */ 679 void arch_suspend_enable_irqs(void) 680 { 681 generic_suspend_enable_irqs(); 682 if (ppc_md.suspend_enable_irqs) 683 ppc_md.suspend_enable_irqs(); 684 } 685 #endif 686 687 #ifdef CONFIG_SMP 688 void __init smp_space_timers(unsigned int max_cpus) 689 { 690 int i; 691 u64 previous_tb = per_cpu(last_jiffy, boot_cpuid); 692 693 /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */ 694 previous_tb -= tb_ticks_per_jiffy; 695 696 for_each_possible_cpu(i) { 697 if (i == boot_cpuid) 698 continue; 699 per_cpu(last_jiffy, i) = previous_tb; 700 } 701 } 702 #endif 703 704 /* 705 * Scheduler clock - returns current time in nanosec units. 706 * 707 * Note: mulhdu(a, b) (multiply high double unsigned) returns 708 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 709 * are 64-bit unsigned numbers. 710 */ 711 unsigned long long sched_clock(void) 712 { 713 if (__USE_RTC()) 714 return get_rtc(); 715 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 716 } 717 718 static int __init get_freq(char *name, int cells, unsigned long *val) 719 { 720 struct device_node *cpu; 721 const unsigned int *fp; 722 int found = 0; 723 724 /* The cpu node should have timebase and clock frequency properties */ 725 cpu = of_find_node_by_type(NULL, "cpu"); 726 727 if (cpu) { 728 fp = of_get_property(cpu, name, NULL); 729 if (fp) { 730 found = 1; 731 *val = of_read_ulong(fp, cells); 732 } 733 734 of_node_put(cpu); 735 } 736 737 return found; 738 } 739 740 /* should become __cpuinit when secondary_cpu_time_init also is */ 741 void start_cpu_decrementer(void) 742 { 743 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) 744 /* Clear any pending timer interrupts */ 745 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 746 747 /* Enable decrementer interrupt */ 748 mtspr(SPRN_TCR, TCR_DIE); 749 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */ 750 } 751 752 void __init generic_calibrate_decr(void) 753 { 754 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 755 756 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 757 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 758 759 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 760 "(not found)\n"); 761 } 762 763 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 764 765 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 766 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 767 768 printk(KERN_ERR "WARNING: Estimating processor frequency " 769 "(not found)\n"); 770 } 771 } 772 773 int update_persistent_clock(struct timespec now) 774 { 775 struct rtc_time tm; 776 777 if (!ppc_md.set_rtc_time) 778 return 0; 779 780 to_tm(now.tv_sec + 1 + timezone_offset, &tm); 781 tm.tm_year -= 1900; 782 tm.tm_mon -= 1; 783 784 return ppc_md.set_rtc_time(&tm); 785 } 786 787 static void __read_persistent_clock(struct timespec *ts) 788 { 789 struct rtc_time tm; 790 static int first = 1; 791 792 ts->tv_nsec = 0; 793 /* XXX this is a litle fragile but will work okay in the short term */ 794 if (first) { 795 first = 0; 796 if (ppc_md.time_init) 797 timezone_offset = ppc_md.time_init(); 798 799 /* get_boot_time() isn't guaranteed to be safe to call late */ 800 if (ppc_md.get_boot_time) { 801 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 802 return; 803 } 804 } 805 if (!ppc_md.get_rtc_time) { 806 ts->tv_sec = 0; 807 return; 808 } 809 ppc_md.get_rtc_time(&tm); 810 811 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, 812 tm.tm_hour, tm.tm_min, tm.tm_sec); 813 } 814 815 void read_persistent_clock(struct timespec *ts) 816 { 817 __read_persistent_clock(ts); 818 819 /* Sanitize it in case real time clock is set below EPOCH */ 820 if (ts->tv_sec < 0) { 821 ts->tv_sec = 0; 822 ts->tv_nsec = 0; 823 } 824 825 } 826 827 /* clocksource code */ 828 static cycle_t rtc_read(struct clocksource *cs) 829 { 830 return (cycle_t)get_rtc(); 831 } 832 833 static cycle_t timebase_read(struct clocksource *cs) 834 { 835 return (cycle_t)get_tb(); 836 } 837 838 void update_vsyscall(struct timespec *wall_time, struct clocksource *clock, 839 u32 mult) 840 { 841 u64 t2x, stamp_xsec; 842 843 if (clock != &clocksource_timebase) 844 return; 845 846 /* Make userspace gettimeofday spin until we're done. */ 847 ++vdso_data->tb_update_count; 848 smp_mb(); 849 850 /* XXX this assumes clock->shift == 22 */ 851 /* 4611686018 ~= 2^(20+64-22) / 1e9 */ 852 t2x = (u64) mult * 4611686018ULL; 853 stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC; 854 do_div(stamp_xsec, 1000000000); 855 stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC; 856 update_gtod(clock->cycle_last, stamp_xsec, t2x); 857 } 858 859 void update_vsyscall_tz(void) 860 { 861 /* Make userspace gettimeofday spin until we're done. */ 862 ++vdso_data->tb_update_count; 863 smp_mb(); 864 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; 865 vdso_data->tz_dsttime = sys_tz.tz_dsttime; 866 smp_mb(); 867 ++vdso_data->tb_update_count; 868 } 869 870 static void __init clocksource_init(void) 871 { 872 struct clocksource *clock; 873 874 if (__USE_RTC()) 875 clock = &clocksource_rtc; 876 else 877 clock = &clocksource_timebase; 878 879 clock->mult = clocksource_hz2mult(tb_ticks_per_sec, clock->shift); 880 881 if (clocksource_register(clock)) { 882 printk(KERN_ERR "clocksource: %s is already registered\n", 883 clock->name); 884 return; 885 } 886 887 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 888 clock->name, clock->mult, clock->shift); 889 } 890 891 static int decrementer_set_next_event(unsigned long evt, 892 struct clock_event_device *dev) 893 { 894 __get_cpu_var(decrementers).next_tb = get_tb_or_rtc() + evt; 895 set_dec(evt); 896 return 0; 897 } 898 899 static void decrementer_set_mode(enum clock_event_mode mode, 900 struct clock_event_device *dev) 901 { 902 if (mode != CLOCK_EVT_MODE_ONESHOT) 903 decrementer_set_next_event(DECREMENTER_MAX, dev); 904 } 905 906 static inline uint64_t div_sc64(unsigned long ticks, unsigned long nsec, 907 int shift) 908 { 909 uint64_t tmp = ((uint64_t)ticks) << shift; 910 911 do_div(tmp, nsec); 912 return tmp; 913 } 914 915 static void __init setup_clockevent_multiplier(unsigned long hz) 916 { 917 u64 mult, shift = 32; 918 919 while (1) { 920 mult = div_sc64(hz, NSEC_PER_SEC, shift); 921 if (mult && (mult >> 32UL) == 0UL) 922 break; 923 924 shift--; 925 } 926 927 decrementer_clockevent.shift = shift; 928 decrementer_clockevent.mult = mult; 929 } 930 931 static void register_decrementer_clockevent(int cpu) 932 { 933 struct clock_event_device *dec = &per_cpu(decrementers, cpu).event; 934 935 *dec = decrementer_clockevent; 936 dec->cpumask = cpumask_of(cpu); 937 938 printk(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 939 dec->name, dec->mult, dec->shift, cpu); 940 941 clockevents_register_device(dec); 942 } 943 944 static void __init init_decrementer_clockevent(void) 945 { 946 int cpu = smp_processor_id(); 947 948 setup_clockevent_multiplier(ppc_tb_freq); 949 decrementer_clockevent.max_delta_ns = 950 clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent); 951 decrementer_clockevent.min_delta_ns = 952 clockevent_delta2ns(2, &decrementer_clockevent); 953 954 register_decrementer_clockevent(cpu); 955 } 956 957 void secondary_cpu_time_init(void) 958 { 959 /* Start the decrementer on CPUs that have manual control 960 * such as BookE 961 */ 962 start_cpu_decrementer(); 963 964 /* FIME: Should make unrelatred change to move snapshot_timebase 965 * call here ! */ 966 register_decrementer_clockevent(smp_processor_id()); 967 } 968 969 /* This function is only called on the boot processor */ 970 void __init time_init(void) 971 { 972 unsigned long flags; 973 struct div_result res; 974 u64 scale, x; 975 unsigned shift; 976 977 if (__USE_RTC()) { 978 /* 601 processor: dec counts down by 128 every 128ns */ 979 ppc_tb_freq = 1000000000; 980 tb_last_jiffy = get_rtcl(); 981 } else { 982 /* Normal PowerPC with timebase register */ 983 ppc_md.calibrate_decr(); 984 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 985 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 986 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 987 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 988 tb_last_jiffy = get_tb(); 989 } 990 991 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 992 tb_ticks_per_sec = ppc_tb_freq; 993 tb_ticks_per_usec = ppc_tb_freq / 1000000; 994 tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000); 995 calc_cputime_factors(); 996 setup_cputime_one_jiffy(); 997 998 /* 999 * Calculate the length of each tick in ns. It will not be 1000 * exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ. 1001 * We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq, 1002 * rounded up. 1003 */ 1004 x = (u64) NSEC_PER_SEC * tb_ticks_per_jiffy + ppc_tb_freq - 1; 1005 do_div(x, ppc_tb_freq); 1006 tick_nsec = x; 1007 last_tick_len = x << TICKLEN_SCALE; 1008 1009 /* 1010 * Compute ticklen_to_xs, which is a factor which gets multiplied 1011 * by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value. 1012 * It is computed as: 1013 * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9) 1014 * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT 1015 * which turns out to be N = 51 - SHIFT_HZ. 1016 * This gives the result as a 0.64 fixed-point fraction. 1017 * That value is reduced by an offset amounting to 1 xsec per 1018 * 2^31 timebase ticks to avoid problems with time going backwards 1019 * by 1 xsec when we do timer_recalc_offset due to losing the 1020 * fractional xsec. That offset is equal to ppc_tb_freq/2^51 1021 * since there are 2^20 xsec in a second. 1022 */ 1023 div128_by_32((1ULL << 51) - ppc_tb_freq, 0, 1024 tb_ticks_per_jiffy << SHIFT_HZ, &res); 1025 div128_by_32(res.result_high, res.result_low, NSEC_PER_SEC, &res); 1026 ticklen_to_xs = res.result_low; 1027 1028 /* Compute tb_to_xs from tick_nsec */ 1029 tb_to_xs = mulhdu(last_tick_len << TICKLEN_SHIFT, ticklen_to_xs); 1030 1031 /* 1032 * Compute scale factor for sched_clock. 1033 * The calibrate_decr() function has set tb_ticks_per_sec, 1034 * which is the timebase frequency. 1035 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 1036 * the 128-bit result as a 64.64 fixed-point number. 1037 * We then shift that number right until it is less than 1.0, 1038 * giving us the scale factor and shift count to use in 1039 * sched_clock(). 1040 */ 1041 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 1042 scale = res.result_low; 1043 for (shift = 0; res.result_high != 0; ++shift) { 1044 scale = (scale >> 1) | (res.result_high << 63); 1045 res.result_high >>= 1; 1046 } 1047 tb_to_ns_scale = scale; 1048 tb_to_ns_shift = shift; 1049 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 1050 boot_tb = get_tb_or_rtc(); 1051 1052 write_seqlock_irqsave(&xtime_lock, flags); 1053 1054 /* If platform provided a timezone (pmac), we correct the time */ 1055 if (timezone_offset) { 1056 sys_tz.tz_minuteswest = -timezone_offset / 60; 1057 sys_tz.tz_dsttime = 0; 1058 } 1059 1060 vdso_data->tb_orig_stamp = tb_last_jiffy; 1061 vdso_data->tb_update_count = 0; 1062 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 1063 vdso_data->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC; 1064 vdso_data->tb_to_xs = tb_to_xs; 1065 1066 write_sequnlock_irqrestore(&xtime_lock, flags); 1067 1068 /* Start the decrementer on CPUs that have manual control 1069 * such as BookE 1070 */ 1071 start_cpu_decrementer(); 1072 1073 /* Register the clocksource, if we're not running on iSeries */ 1074 if (!firmware_has_feature(FW_FEATURE_ISERIES)) 1075 clocksource_init(); 1076 1077 init_decrementer_clockevent(); 1078 } 1079 1080 1081 #define FEBRUARY 2 1082 #define STARTOFTIME 1970 1083 #define SECDAY 86400L 1084 #define SECYR (SECDAY * 365) 1085 #define leapyear(year) ((year) % 4 == 0 && \ 1086 ((year) % 100 != 0 || (year) % 400 == 0)) 1087 #define days_in_year(a) (leapyear(a) ? 366 : 365) 1088 #define days_in_month(a) (month_days[(a) - 1]) 1089 1090 static int month_days[12] = { 1091 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 1092 }; 1093 1094 /* 1095 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) 1096 */ 1097 void GregorianDay(struct rtc_time * tm) 1098 { 1099 int leapsToDate; 1100 int lastYear; 1101 int day; 1102 int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; 1103 1104 lastYear = tm->tm_year - 1; 1105 1106 /* 1107 * Number of leap corrections to apply up to end of last year 1108 */ 1109 leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400; 1110 1111 /* 1112 * This year is a leap year if it is divisible by 4 except when it is 1113 * divisible by 100 unless it is divisible by 400 1114 * 1115 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was 1116 */ 1117 day = tm->tm_mon > 2 && leapyear(tm->tm_year); 1118 1119 day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + 1120 tm->tm_mday; 1121 1122 tm->tm_wday = day % 7; 1123 } 1124 1125 void to_tm(int tim, struct rtc_time * tm) 1126 { 1127 register int i; 1128 register long hms, day; 1129 1130 day = tim / SECDAY; 1131 hms = tim % SECDAY; 1132 1133 /* Hours, minutes, seconds are easy */ 1134 tm->tm_hour = hms / 3600; 1135 tm->tm_min = (hms % 3600) / 60; 1136 tm->tm_sec = (hms % 3600) % 60; 1137 1138 /* Number of years in days */ 1139 for (i = STARTOFTIME; day >= days_in_year(i); i++) 1140 day -= days_in_year(i); 1141 tm->tm_year = i; 1142 1143 /* Number of months in days left */ 1144 if (leapyear(tm->tm_year)) 1145 days_in_month(FEBRUARY) = 29; 1146 for (i = 1; day >= days_in_month(i); i++) 1147 day -= days_in_month(i); 1148 days_in_month(FEBRUARY) = 28; 1149 tm->tm_mon = i; 1150 1151 /* Days are what is left over (+1) from all that. */ 1152 tm->tm_mday = day + 1; 1153 1154 /* 1155 * Determine the day of week 1156 */ 1157 GregorianDay(tm); 1158 } 1159 1160 /* Auxiliary function to compute scaling factors */ 1161 /* Actually the choice of a timebase running at 1/4 the of the bus 1162 * frequency giving resolution of a few tens of nanoseconds is quite nice. 1163 * It makes this computation very precise (27-28 bits typically) which 1164 * is optimistic considering the stability of most processor clock 1165 * oscillators and the precision with which the timebase frequency 1166 * is measured but does not harm. 1167 */ 1168 unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale) 1169 { 1170 unsigned mlt=0, tmp, err; 1171 /* No concern for performance, it's done once: use a stupid 1172 * but safe and compact method to find the multiplier. 1173 */ 1174 1175 for (tmp = 1U<<31; tmp != 0; tmp >>= 1) { 1176 if (mulhwu(inscale, mlt|tmp) < outscale) 1177 mlt |= tmp; 1178 } 1179 1180 /* We might still be off by 1 for the best approximation. 1181 * A side effect of this is that if outscale is too large 1182 * the returned value will be zero. 1183 * Many corner cases have been checked and seem to work, 1184 * some might have been forgotten in the test however. 1185 */ 1186 1187 err = inscale * (mlt+1); 1188 if (err <= inscale/2) 1189 mlt++; 1190 return mlt; 1191 } 1192 1193 /* 1194 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 1195 * result. 1196 */ 1197 void div128_by_32(u64 dividend_high, u64 dividend_low, 1198 unsigned divisor, struct div_result *dr) 1199 { 1200 unsigned long a, b, c, d; 1201 unsigned long w, x, y, z; 1202 u64 ra, rb, rc; 1203 1204 a = dividend_high >> 32; 1205 b = dividend_high & 0xffffffff; 1206 c = dividend_low >> 32; 1207 d = dividend_low & 0xffffffff; 1208 1209 w = a / divisor; 1210 ra = ((u64)(a - (w * divisor)) << 32) + b; 1211 1212 rb = ((u64) do_div(ra, divisor) << 32) + c; 1213 x = ra; 1214 1215 rc = ((u64) do_div(rb, divisor) << 32) + d; 1216 y = rb; 1217 1218 do_div(rc, divisor); 1219 z = rc; 1220 1221 dr->result_high = ((u64)w << 32) + x; 1222 dr->result_low = ((u64)y << 32) + z; 1223 1224 } 1225 1226 /* We don't need to calibrate delay, we use the CPU timebase for that */ 1227 void calibrate_delay(void) 1228 { 1229 /* Some generic code (such as spinlock debug) use loops_per_jiffy 1230 * as the number of __delay(1) in a jiffy, so make it so 1231 */ 1232 loops_per_jiffy = tb_ticks_per_jiffy; 1233 } 1234 1235 static int __init rtc_init(void) 1236 { 1237 struct platform_device *pdev; 1238 1239 if (!ppc_md.get_rtc_time) 1240 return -ENODEV; 1241 1242 pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0); 1243 if (IS_ERR(pdev)) 1244 return PTR_ERR(pdev); 1245 1246 return 0; 1247 } 1248 1249 module_init(rtc_init); 1250