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 */ 152 153 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 unsigned long 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(ppc_proc_freq); 165 unsigned long ppc_tb_freq; 166 167 static DEFINE_PER_CPU(u64, last_jiffy); 168 169 #ifdef CONFIG_VIRT_CPU_ACCOUNTING 170 /* 171 * Factors for converting from cputime_t (timebase ticks) to 172 * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds). 173 * These are all stored as 0.64 fixed-point binary fractions. 174 */ 175 u64 __cputime_jiffies_factor; 176 EXPORT_SYMBOL(__cputime_jiffies_factor); 177 u64 __cputime_msec_factor; 178 EXPORT_SYMBOL(__cputime_msec_factor); 179 u64 __cputime_sec_factor; 180 EXPORT_SYMBOL(__cputime_sec_factor); 181 u64 __cputime_clockt_factor; 182 EXPORT_SYMBOL(__cputime_clockt_factor); 183 DEFINE_PER_CPU(unsigned long, cputime_last_delta); 184 DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta); 185 186 cputime_t cputime_one_jiffy; 187 188 static void calc_cputime_factors(void) 189 { 190 struct div_result res; 191 192 div128_by_32(HZ, 0, tb_ticks_per_sec, &res); 193 __cputime_jiffies_factor = res.result_low; 194 div128_by_32(1000, 0, tb_ticks_per_sec, &res); 195 __cputime_msec_factor = res.result_low; 196 div128_by_32(1, 0, tb_ticks_per_sec, &res); 197 __cputime_sec_factor = res.result_low; 198 div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res); 199 __cputime_clockt_factor = res.result_low; 200 } 201 202 /* 203 * Read the PURR on systems that have it, otherwise the timebase. 204 */ 205 static u64 read_purr(void) 206 { 207 if (cpu_has_feature(CPU_FTR_PURR)) 208 return mfspr(SPRN_PURR); 209 return mftb(); 210 } 211 212 /* 213 * Read the SPURR on systems that have it, otherwise the purr 214 */ 215 static u64 read_spurr(u64 purr) 216 { 217 /* 218 * cpus without PURR won't have a SPURR 219 * We already know the former when we use this, so tell gcc 220 */ 221 if (cpu_has_feature(CPU_FTR_PURR) && cpu_has_feature(CPU_FTR_SPURR)) 222 return mfspr(SPRN_SPURR); 223 return purr; 224 } 225 226 /* 227 * Account time for a transition between system, hard irq 228 * or soft irq state. 229 */ 230 void account_system_vtime(struct task_struct *tsk) 231 { 232 u64 now, nowscaled, delta, deltascaled, sys_time; 233 unsigned long flags; 234 235 local_irq_save(flags); 236 now = read_purr(); 237 nowscaled = read_spurr(now); 238 delta = now - get_paca()->startpurr; 239 deltascaled = nowscaled - get_paca()->startspurr; 240 get_paca()->startpurr = now; 241 get_paca()->startspurr = nowscaled; 242 if (!in_interrupt()) { 243 /* deltascaled includes both user and system time. 244 * Hence scale it based on the purr ratio to estimate 245 * the system time */ 246 sys_time = get_paca()->system_time; 247 if (get_paca()->user_time) 248 deltascaled = deltascaled * sys_time / 249 (sys_time + get_paca()->user_time); 250 delta += sys_time; 251 get_paca()->system_time = 0; 252 } 253 if (in_irq() || idle_task(smp_processor_id()) != tsk) 254 account_system_time(tsk, 0, delta, deltascaled); 255 else 256 account_idle_time(delta); 257 __get_cpu_var(cputime_last_delta) = delta; 258 __get_cpu_var(cputime_scaled_last_delta) = deltascaled; 259 local_irq_restore(flags); 260 } 261 EXPORT_SYMBOL_GPL(account_system_vtime); 262 263 /* 264 * Transfer the user and system times accumulated in the paca 265 * by the exception entry and exit code to the generic process 266 * user and system time records. 267 * Must be called with interrupts disabled. 268 */ 269 void account_process_tick(struct task_struct *tsk, int user_tick) 270 { 271 cputime_t utime, utimescaled; 272 273 utime = get_paca()->user_time; 274 get_paca()->user_time = 0; 275 utimescaled = cputime_to_scaled(utime); 276 account_user_time(tsk, utime, utimescaled); 277 } 278 279 /* 280 * Stuff for accounting stolen time. 281 */ 282 struct cpu_purr_data { 283 int initialized; /* thread is running */ 284 u64 tb; /* last TB value read */ 285 u64 purr; /* last PURR value read */ 286 u64 spurr; /* last SPURR value read */ 287 }; 288 289 /* 290 * Each entry in the cpu_purr_data array is manipulated only by its 291 * "owner" cpu -- usually in the timer interrupt but also occasionally 292 * in process context for cpu online. As long as cpus do not touch 293 * each others' cpu_purr_data, disabling local interrupts is 294 * sufficient to serialize accesses. 295 */ 296 static DEFINE_PER_CPU(struct cpu_purr_data, cpu_purr_data); 297 298 static void snapshot_tb_and_purr(void *data) 299 { 300 unsigned long flags; 301 struct cpu_purr_data *p = &__get_cpu_var(cpu_purr_data); 302 303 local_irq_save(flags); 304 p->tb = get_tb_or_rtc(); 305 p->purr = mfspr(SPRN_PURR); 306 wmb(); 307 p->initialized = 1; 308 local_irq_restore(flags); 309 } 310 311 /* 312 * Called during boot when all cpus have come up. 313 */ 314 void snapshot_timebases(void) 315 { 316 if (!cpu_has_feature(CPU_FTR_PURR)) 317 return; 318 on_each_cpu(snapshot_tb_and_purr, NULL, 1); 319 } 320 321 /* 322 * Must be called with interrupts disabled. 323 */ 324 void calculate_steal_time(void) 325 { 326 u64 tb, purr; 327 s64 stolen; 328 struct cpu_purr_data *pme; 329 330 pme = &__get_cpu_var(cpu_purr_data); 331 if (!pme->initialized) 332 return; /* !CPU_FTR_PURR or early in early boot */ 333 tb = mftb(); 334 purr = mfspr(SPRN_PURR); 335 stolen = (tb - pme->tb) - (purr - pme->purr); 336 if (stolen > 0) { 337 if (idle_task(smp_processor_id()) != current) 338 account_steal_time(stolen); 339 else 340 account_idle_time(stolen); 341 } 342 pme->tb = tb; 343 pme->purr = purr; 344 } 345 346 #ifdef CONFIG_PPC_SPLPAR 347 /* 348 * Must be called before the cpu is added to the online map when 349 * a cpu is being brought up at runtime. 350 */ 351 static void snapshot_purr(void) 352 { 353 struct cpu_purr_data *pme; 354 unsigned long flags; 355 356 if (!cpu_has_feature(CPU_FTR_PURR)) 357 return; 358 local_irq_save(flags); 359 pme = &__get_cpu_var(cpu_purr_data); 360 pme->tb = mftb(); 361 pme->purr = mfspr(SPRN_PURR); 362 pme->initialized = 1; 363 local_irq_restore(flags); 364 } 365 366 #endif /* CONFIG_PPC_SPLPAR */ 367 368 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */ 369 #define calc_cputime_factors() 370 #define calculate_steal_time() do { } while (0) 371 #endif 372 373 #if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR)) 374 #define snapshot_purr() do { } while (0) 375 #endif 376 377 /* 378 * Called when a cpu comes up after the system has finished booting, 379 * i.e. as a result of a hotplug cpu action. 380 */ 381 void snapshot_timebase(void) 382 { 383 __get_cpu_var(last_jiffy) = get_tb_or_rtc(); 384 snapshot_purr(); 385 } 386 387 void __delay(unsigned long loops) 388 { 389 unsigned long start; 390 int diff; 391 392 if (__USE_RTC()) { 393 start = get_rtcl(); 394 do { 395 /* the RTCL register wraps at 1000000000 */ 396 diff = get_rtcl() - start; 397 if (diff < 0) 398 diff += 1000000000; 399 } while (diff < loops); 400 } else { 401 start = get_tbl(); 402 while (get_tbl() - start < loops) 403 HMT_low(); 404 HMT_medium(); 405 } 406 } 407 EXPORT_SYMBOL(__delay); 408 409 void udelay(unsigned long usecs) 410 { 411 __delay(tb_ticks_per_usec * usecs); 412 } 413 EXPORT_SYMBOL(udelay); 414 415 #ifdef CONFIG_SMP 416 unsigned long profile_pc(struct pt_regs *regs) 417 { 418 unsigned long pc = instruction_pointer(regs); 419 420 if (in_lock_functions(pc)) 421 return regs->link; 422 423 return pc; 424 } 425 EXPORT_SYMBOL(profile_pc); 426 #endif 427 428 #ifdef CONFIG_PPC_ISERIES 429 430 /* 431 * This function recalibrates the timebase based on the 49-bit time-of-day 432 * value in the Titan chip. The Titan is much more accurate than the value 433 * returned by the service processor for the timebase frequency. 434 */ 435 436 static int __init iSeries_tb_recal(void) 437 { 438 unsigned long titan, tb; 439 440 /* Make sure we only run on iSeries */ 441 if (!firmware_has_feature(FW_FEATURE_ISERIES)) 442 return -ENODEV; 443 444 tb = get_tb(); 445 titan = HvCallXm_loadTod(); 446 if ( iSeries_recal_titan ) { 447 unsigned long tb_ticks = tb - iSeries_recal_tb; 448 unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12; 449 unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec; 450 unsigned long new_tb_ticks_per_jiffy = 451 DIV_ROUND_CLOSEST(new_tb_ticks_per_sec, HZ); 452 long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy; 453 char sign = '+'; 454 /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */ 455 new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ; 456 457 if ( tick_diff < 0 ) { 458 tick_diff = -tick_diff; 459 sign = '-'; 460 } 461 if ( tick_diff ) { 462 if ( tick_diff < tb_ticks_per_jiffy/25 ) { 463 printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n", 464 new_tb_ticks_per_jiffy, sign, tick_diff ); 465 tb_ticks_per_jiffy = new_tb_ticks_per_jiffy; 466 tb_ticks_per_sec = new_tb_ticks_per_sec; 467 calc_cputime_factors(); 468 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 469 setup_cputime_one_jiffy(); 470 } 471 else { 472 printk( "Titan recalibrate: FAILED (difference > 4 percent)\n" 473 " new tb_ticks_per_jiffy = %lu\n" 474 " old tb_ticks_per_jiffy = %lu\n", 475 new_tb_ticks_per_jiffy, tb_ticks_per_jiffy ); 476 } 477 } 478 } 479 iSeries_recal_titan = titan; 480 iSeries_recal_tb = tb; 481 482 /* Called here as now we know accurate values for the timebase */ 483 clocksource_init(); 484 return 0; 485 } 486 late_initcall(iSeries_tb_recal); 487 488 /* Called from platform early init */ 489 void __init iSeries_time_init_early(void) 490 { 491 iSeries_recal_tb = get_tb(); 492 iSeries_recal_titan = HvCallXm_loadTod(); 493 } 494 #endif /* CONFIG_PPC_ISERIES */ 495 496 #ifdef CONFIG_PERF_EVENTS 497 498 /* 499 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable... 500 */ 501 #ifdef CONFIG_PPC64 502 static inline unsigned long test_perf_event_pending(void) 503 { 504 unsigned long x; 505 506 asm volatile("lbz %0,%1(13)" 507 : "=r" (x) 508 : "i" (offsetof(struct paca_struct, perf_event_pending))); 509 return x; 510 } 511 512 static inline void set_perf_event_pending_flag(void) 513 { 514 asm volatile("stb %0,%1(13)" : : 515 "r" (1), 516 "i" (offsetof(struct paca_struct, perf_event_pending))); 517 } 518 519 static inline void clear_perf_event_pending(void) 520 { 521 asm volatile("stb %0,%1(13)" : : 522 "r" (0), 523 "i" (offsetof(struct paca_struct, perf_event_pending))); 524 } 525 526 #else /* 32-bit */ 527 528 DEFINE_PER_CPU(u8, perf_event_pending); 529 530 #define set_perf_event_pending_flag() __get_cpu_var(perf_event_pending) = 1 531 #define test_perf_event_pending() __get_cpu_var(perf_event_pending) 532 #define clear_perf_event_pending() __get_cpu_var(perf_event_pending) = 0 533 534 #endif /* 32 vs 64 bit */ 535 536 void set_perf_event_pending(void) 537 { 538 preempt_disable(); 539 set_perf_event_pending_flag(); 540 set_dec(1); 541 preempt_enable(); 542 } 543 544 #else /* CONFIG_PERF_EVENTS */ 545 546 #define test_perf_event_pending() 0 547 #define clear_perf_event_pending() 548 549 #endif /* CONFIG_PERF_EVENTS */ 550 551 /* 552 * For iSeries shared processors, we have to let the hypervisor 553 * set the hardware decrementer. We set a virtual decrementer 554 * in the lppaca and call the hypervisor if the virtual 555 * decrementer is less than the current value in the hardware 556 * decrementer. (almost always the new decrementer value will 557 * be greater than the current hardware decementer so the hypervisor 558 * call will not be needed) 559 */ 560 561 /* 562 * timer_interrupt - gets called when the decrementer overflows, 563 * with interrupts disabled. 564 */ 565 void timer_interrupt(struct pt_regs * regs) 566 { 567 struct pt_regs *old_regs; 568 struct decrementer_clock *decrementer = &__get_cpu_var(decrementers); 569 struct clock_event_device *evt = &decrementer->event; 570 u64 now; 571 572 trace_timer_interrupt_entry(regs); 573 574 __get_cpu_var(irq_stat).timer_irqs++; 575 576 /* Ensure a positive value is written to the decrementer, or else 577 * some CPUs will continuue to take decrementer exceptions */ 578 set_dec(DECREMENTER_MAX); 579 580 #if defined(CONFIG_PPC32) && defined(CONFIG_PMAC) 581 if (atomic_read(&ppc_n_lost_interrupts) != 0) 582 do_IRQ(regs); 583 #endif 584 585 old_regs = set_irq_regs(regs); 586 irq_enter(); 587 588 calculate_steal_time(); 589 590 if (test_perf_event_pending()) { 591 clear_perf_event_pending(); 592 perf_event_do_pending(); 593 } 594 595 #ifdef CONFIG_PPC_ISERIES 596 if (firmware_has_feature(FW_FEATURE_ISERIES)) 597 get_lppaca()->int_dword.fields.decr_int = 0; 598 #endif 599 600 now = get_tb_or_rtc(); 601 if (now >= decrementer->next_tb) { 602 decrementer->next_tb = ~(u64)0; 603 if (evt->event_handler) 604 evt->event_handler(evt); 605 } else { 606 now = decrementer->next_tb - now; 607 if (now <= DECREMENTER_MAX) 608 set_dec((int)now); 609 } 610 611 #ifdef CONFIG_PPC_ISERIES 612 if (firmware_has_feature(FW_FEATURE_ISERIES) && hvlpevent_is_pending()) 613 process_hvlpevents(); 614 #endif 615 616 #ifdef CONFIG_PPC64 617 /* collect purr register values often, for accurate calculations */ 618 if (firmware_has_feature(FW_FEATURE_SPLPAR)) { 619 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); 620 cu->current_tb = mfspr(SPRN_PURR); 621 } 622 #endif 623 624 irq_exit(); 625 set_irq_regs(old_regs); 626 627 trace_timer_interrupt_exit(regs); 628 } 629 630 #ifdef CONFIG_SUSPEND 631 static void generic_suspend_disable_irqs(void) 632 { 633 /* Disable the decrementer, so that it doesn't interfere 634 * with suspending. 635 */ 636 637 set_dec(0x7fffffff); 638 local_irq_disable(); 639 set_dec(0x7fffffff); 640 } 641 642 static void generic_suspend_enable_irqs(void) 643 { 644 local_irq_enable(); 645 } 646 647 /* Overrides the weak version in kernel/power/main.c */ 648 void arch_suspend_disable_irqs(void) 649 { 650 if (ppc_md.suspend_disable_irqs) 651 ppc_md.suspend_disable_irqs(); 652 generic_suspend_disable_irqs(); 653 } 654 655 /* Overrides the weak version in kernel/power/main.c */ 656 void arch_suspend_enable_irqs(void) 657 { 658 generic_suspend_enable_irqs(); 659 if (ppc_md.suspend_enable_irqs) 660 ppc_md.suspend_enable_irqs(); 661 } 662 #endif 663 664 /* 665 * Scheduler clock - returns current time in nanosec units. 666 * 667 * Note: mulhdu(a, b) (multiply high double unsigned) returns 668 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 669 * are 64-bit unsigned numbers. 670 */ 671 unsigned long long sched_clock(void) 672 { 673 if (__USE_RTC()) 674 return get_rtc(); 675 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 676 } 677 678 static int __init get_freq(char *name, int cells, unsigned long *val) 679 { 680 struct device_node *cpu; 681 const unsigned int *fp; 682 int found = 0; 683 684 /* The cpu node should have timebase and clock frequency properties */ 685 cpu = of_find_node_by_type(NULL, "cpu"); 686 687 if (cpu) { 688 fp = of_get_property(cpu, name, NULL); 689 if (fp) { 690 found = 1; 691 *val = of_read_ulong(fp, cells); 692 } 693 694 of_node_put(cpu); 695 } 696 697 return found; 698 } 699 700 /* should become __cpuinit when secondary_cpu_time_init also is */ 701 void start_cpu_decrementer(void) 702 { 703 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) 704 /* Clear any pending timer interrupts */ 705 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 706 707 /* Enable decrementer interrupt */ 708 mtspr(SPRN_TCR, TCR_DIE); 709 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */ 710 } 711 712 void __init generic_calibrate_decr(void) 713 { 714 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 715 716 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 717 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 718 719 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 720 "(not found)\n"); 721 } 722 723 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 724 725 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 726 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 727 728 printk(KERN_ERR "WARNING: Estimating processor frequency " 729 "(not found)\n"); 730 } 731 } 732 733 int update_persistent_clock(struct timespec now) 734 { 735 struct rtc_time tm; 736 737 if (!ppc_md.set_rtc_time) 738 return 0; 739 740 to_tm(now.tv_sec + 1 + timezone_offset, &tm); 741 tm.tm_year -= 1900; 742 tm.tm_mon -= 1; 743 744 return ppc_md.set_rtc_time(&tm); 745 } 746 747 static void __read_persistent_clock(struct timespec *ts) 748 { 749 struct rtc_time tm; 750 static int first = 1; 751 752 ts->tv_nsec = 0; 753 /* XXX this is a litle fragile but will work okay in the short term */ 754 if (first) { 755 first = 0; 756 if (ppc_md.time_init) 757 timezone_offset = ppc_md.time_init(); 758 759 /* get_boot_time() isn't guaranteed to be safe to call late */ 760 if (ppc_md.get_boot_time) { 761 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 762 return; 763 } 764 } 765 if (!ppc_md.get_rtc_time) { 766 ts->tv_sec = 0; 767 return; 768 } 769 ppc_md.get_rtc_time(&tm); 770 771 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, 772 tm.tm_hour, tm.tm_min, tm.tm_sec); 773 } 774 775 void read_persistent_clock(struct timespec *ts) 776 { 777 __read_persistent_clock(ts); 778 779 /* Sanitize it in case real time clock is set below EPOCH */ 780 if (ts->tv_sec < 0) { 781 ts->tv_sec = 0; 782 ts->tv_nsec = 0; 783 } 784 785 } 786 787 /* clocksource code */ 788 static cycle_t rtc_read(struct clocksource *cs) 789 { 790 return (cycle_t)get_rtc(); 791 } 792 793 static cycle_t timebase_read(struct clocksource *cs) 794 { 795 return (cycle_t)get_tb(); 796 } 797 798 void update_vsyscall(struct timespec *wall_time, struct timespec *wtm, 799 struct clocksource *clock, u32 mult) 800 { 801 u64 new_tb_to_xs, new_stamp_xsec; 802 u32 frac_sec; 803 804 if (clock != &clocksource_timebase) 805 return; 806 807 /* Make userspace gettimeofday spin until we're done. */ 808 ++vdso_data->tb_update_count; 809 smp_mb(); 810 811 /* XXX this assumes clock->shift == 22 */ 812 /* 4611686018 ~= 2^(20+64-22) / 1e9 */ 813 new_tb_to_xs = (u64) mult * 4611686018ULL; 814 new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC; 815 do_div(new_stamp_xsec, 1000000000); 816 new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC; 817 818 BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC); 819 /* this is tv_nsec / 1e9 as a 0.32 fraction */ 820 frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32; 821 822 /* 823 * tb_update_count is used to allow the userspace gettimeofday code 824 * to assure itself that it sees a consistent view of the tb_to_xs and 825 * stamp_xsec variables. It reads the tb_update_count, then reads 826 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If 827 * the two values of tb_update_count match and are even then the 828 * tb_to_xs and stamp_xsec values are consistent. If not, then it 829 * loops back and reads them again until this criteria is met. 830 * We expect the caller to have done the first increment of 831 * vdso_data->tb_update_count already. 832 */ 833 vdso_data->tb_orig_stamp = clock->cycle_last; 834 vdso_data->stamp_xsec = new_stamp_xsec; 835 vdso_data->tb_to_xs = new_tb_to_xs; 836 vdso_data->wtom_clock_sec = wtm->tv_sec; 837 vdso_data->wtom_clock_nsec = wtm->tv_nsec; 838 vdso_data->stamp_xtime = *wall_time; 839 vdso_data->stamp_sec_fraction = frac_sec; 840 smp_wmb(); 841 ++(vdso_data->tb_update_count); 842 } 843 844 void update_vsyscall_tz(void) 845 { 846 /* Make userspace gettimeofday spin until we're done. */ 847 ++vdso_data->tb_update_count; 848 smp_mb(); 849 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; 850 vdso_data->tz_dsttime = sys_tz.tz_dsttime; 851 smp_mb(); 852 ++vdso_data->tb_update_count; 853 } 854 855 static void __init clocksource_init(void) 856 { 857 struct clocksource *clock; 858 859 if (__USE_RTC()) 860 clock = &clocksource_rtc; 861 else 862 clock = &clocksource_timebase; 863 864 clock->mult = clocksource_hz2mult(tb_ticks_per_sec, clock->shift); 865 866 if (clocksource_register(clock)) { 867 printk(KERN_ERR "clocksource: %s is already registered\n", 868 clock->name); 869 return; 870 } 871 872 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 873 clock->name, clock->mult, clock->shift); 874 } 875 876 static int decrementer_set_next_event(unsigned long evt, 877 struct clock_event_device *dev) 878 { 879 __get_cpu_var(decrementers).next_tb = get_tb_or_rtc() + evt; 880 set_dec(evt); 881 return 0; 882 } 883 884 static void decrementer_set_mode(enum clock_event_mode mode, 885 struct clock_event_device *dev) 886 { 887 if (mode != CLOCK_EVT_MODE_ONESHOT) 888 decrementer_set_next_event(DECREMENTER_MAX, dev); 889 } 890 891 static inline uint64_t div_sc64(unsigned long ticks, unsigned long nsec, 892 int shift) 893 { 894 uint64_t tmp = ((uint64_t)ticks) << shift; 895 896 do_div(tmp, nsec); 897 return tmp; 898 } 899 900 static void __init setup_clockevent_multiplier(unsigned long hz) 901 { 902 u64 mult, shift = 32; 903 904 while (1) { 905 mult = div_sc64(hz, NSEC_PER_SEC, shift); 906 if (mult && (mult >> 32UL) == 0UL) 907 break; 908 909 shift--; 910 } 911 912 decrementer_clockevent.shift = shift; 913 decrementer_clockevent.mult = mult; 914 } 915 916 static void register_decrementer_clockevent(int cpu) 917 { 918 struct clock_event_device *dec = &per_cpu(decrementers, cpu).event; 919 920 *dec = decrementer_clockevent; 921 dec->cpumask = cpumask_of(cpu); 922 923 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 924 dec->name, dec->mult, dec->shift, cpu); 925 926 clockevents_register_device(dec); 927 } 928 929 static void __init init_decrementer_clockevent(void) 930 { 931 int cpu = smp_processor_id(); 932 933 setup_clockevent_multiplier(ppc_tb_freq); 934 decrementer_clockevent.max_delta_ns = 935 clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent); 936 decrementer_clockevent.min_delta_ns = 937 clockevent_delta2ns(2, &decrementer_clockevent); 938 939 register_decrementer_clockevent(cpu); 940 } 941 942 void secondary_cpu_time_init(void) 943 { 944 /* Start the decrementer on CPUs that have manual control 945 * such as BookE 946 */ 947 start_cpu_decrementer(); 948 949 /* FIME: Should make unrelatred change to move snapshot_timebase 950 * call here ! */ 951 register_decrementer_clockevent(smp_processor_id()); 952 } 953 954 /* This function is only called on the boot processor */ 955 void __init time_init(void) 956 { 957 struct div_result res; 958 u64 scale; 959 unsigned shift; 960 961 if (__USE_RTC()) { 962 /* 601 processor: dec counts down by 128 every 128ns */ 963 ppc_tb_freq = 1000000000; 964 } else { 965 /* Normal PowerPC with timebase register */ 966 ppc_md.calibrate_decr(); 967 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 968 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 969 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 970 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 971 } 972 973 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 974 tb_ticks_per_sec = ppc_tb_freq; 975 tb_ticks_per_usec = ppc_tb_freq / 1000000; 976 calc_cputime_factors(); 977 setup_cputime_one_jiffy(); 978 979 /* 980 * Compute scale factor for sched_clock. 981 * The calibrate_decr() function has set tb_ticks_per_sec, 982 * which is the timebase frequency. 983 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 984 * the 128-bit result as a 64.64 fixed-point number. 985 * We then shift that number right until it is less than 1.0, 986 * giving us the scale factor and shift count to use in 987 * sched_clock(). 988 */ 989 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 990 scale = res.result_low; 991 for (shift = 0; res.result_high != 0; ++shift) { 992 scale = (scale >> 1) | (res.result_high << 63); 993 res.result_high >>= 1; 994 } 995 tb_to_ns_scale = scale; 996 tb_to_ns_shift = shift; 997 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 998 boot_tb = get_tb_or_rtc(); 999 1000 /* If platform provided a timezone (pmac), we correct the time */ 1001 if (timezone_offset) { 1002 sys_tz.tz_minuteswest = -timezone_offset / 60; 1003 sys_tz.tz_dsttime = 0; 1004 } 1005 1006 vdso_data->tb_update_count = 0; 1007 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 1008 1009 /* Start the decrementer on CPUs that have manual control 1010 * such as BookE 1011 */ 1012 start_cpu_decrementer(); 1013 1014 /* Register the clocksource, if we're not running on iSeries */ 1015 if (!firmware_has_feature(FW_FEATURE_ISERIES)) 1016 clocksource_init(); 1017 1018 init_decrementer_clockevent(); 1019 } 1020 1021 1022 #define FEBRUARY 2 1023 #define STARTOFTIME 1970 1024 #define SECDAY 86400L 1025 #define SECYR (SECDAY * 365) 1026 #define leapyear(year) ((year) % 4 == 0 && \ 1027 ((year) % 100 != 0 || (year) % 400 == 0)) 1028 #define days_in_year(a) (leapyear(a) ? 366 : 365) 1029 #define days_in_month(a) (month_days[(a) - 1]) 1030 1031 static int month_days[12] = { 1032 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 1033 }; 1034 1035 /* 1036 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) 1037 */ 1038 void GregorianDay(struct rtc_time * tm) 1039 { 1040 int leapsToDate; 1041 int lastYear; 1042 int day; 1043 int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; 1044 1045 lastYear = tm->tm_year - 1; 1046 1047 /* 1048 * Number of leap corrections to apply up to end of last year 1049 */ 1050 leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400; 1051 1052 /* 1053 * This year is a leap year if it is divisible by 4 except when it is 1054 * divisible by 100 unless it is divisible by 400 1055 * 1056 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was 1057 */ 1058 day = tm->tm_mon > 2 && leapyear(tm->tm_year); 1059 1060 day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + 1061 tm->tm_mday; 1062 1063 tm->tm_wday = day % 7; 1064 } 1065 1066 void to_tm(int tim, struct rtc_time * tm) 1067 { 1068 register int i; 1069 register long hms, day; 1070 1071 day = tim / SECDAY; 1072 hms = tim % SECDAY; 1073 1074 /* Hours, minutes, seconds are easy */ 1075 tm->tm_hour = hms / 3600; 1076 tm->tm_min = (hms % 3600) / 60; 1077 tm->tm_sec = (hms % 3600) % 60; 1078 1079 /* Number of years in days */ 1080 for (i = STARTOFTIME; day >= days_in_year(i); i++) 1081 day -= days_in_year(i); 1082 tm->tm_year = i; 1083 1084 /* Number of months in days left */ 1085 if (leapyear(tm->tm_year)) 1086 days_in_month(FEBRUARY) = 29; 1087 for (i = 1; day >= days_in_month(i); i++) 1088 day -= days_in_month(i); 1089 days_in_month(FEBRUARY) = 28; 1090 tm->tm_mon = i; 1091 1092 /* Days are what is left over (+1) from all that. */ 1093 tm->tm_mday = day + 1; 1094 1095 /* 1096 * Determine the day of week 1097 */ 1098 GregorianDay(tm); 1099 } 1100 1101 /* 1102 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 1103 * result. 1104 */ 1105 void div128_by_32(u64 dividend_high, u64 dividend_low, 1106 unsigned divisor, struct div_result *dr) 1107 { 1108 unsigned long a, b, c, d; 1109 unsigned long w, x, y, z; 1110 u64 ra, rb, rc; 1111 1112 a = dividend_high >> 32; 1113 b = dividend_high & 0xffffffff; 1114 c = dividend_low >> 32; 1115 d = dividend_low & 0xffffffff; 1116 1117 w = a / divisor; 1118 ra = ((u64)(a - (w * divisor)) << 32) + b; 1119 1120 rb = ((u64) do_div(ra, divisor) << 32) + c; 1121 x = ra; 1122 1123 rc = ((u64) do_div(rb, divisor) << 32) + d; 1124 y = rb; 1125 1126 do_div(rc, divisor); 1127 z = rc; 1128 1129 dr->result_high = ((u64)w << 32) + x; 1130 dr->result_low = ((u64)y << 32) + z; 1131 1132 } 1133 1134 /* We don't need to calibrate delay, we use the CPU timebase for that */ 1135 void calibrate_delay(void) 1136 { 1137 /* Some generic code (such as spinlock debug) use loops_per_jiffy 1138 * as the number of __delay(1) in a jiffy, so make it so 1139 */ 1140 loops_per_jiffy = tb_ticks_per_jiffy; 1141 } 1142 1143 static int __init rtc_init(void) 1144 { 1145 struct platform_device *pdev; 1146 1147 if (!ppc_md.get_rtc_time) 1148 return -ENODEV; 1149 1150 pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0); 1151 if (IS_ERR(pdev)) 1152 return PTR_ERR(pdev); 1153 1154 return 0; 1155 } 1156 1157 module_init(rtc_init); 1158