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 #ifdef CONFIG_PPC32 581 if (atomic_read(&ppc_n_lost_interrupts) != 0) 582 do_IRQ(regs); 583 #endif 584 585 now = get_tb_or_rtc(); 586 if (now < decrementer->next_tb) { 587 /* not time for this event yet */ 588 now = decrementer->next_tb - now; 589 if (now <= DECREMENTER_MAX) 590 set_dec((int)now); 591 trace_timer_interrupt_exit(regs); 592 return; 593 } 594 old_regs = set_irq_regs(regs); 595 irq_enter(); 596 597 calculate_steal_time(); 598 599 if (test_perf_event_pending()) { 600 clear_perf_event_pending(); 601 perf_event_do_pending(); 602 } 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 #ifdef CONFIG_SUSPEND 632 static void generic_suspend_disable_irqs(void) 633 { 634 /* Disable the decrementer, so that it doesn't interfere 635 * with suspending. 636 */ 637 638 set_dec(0x7fffffff); 639 local_irq_disable(); 640 set_dec(0x7fffffff); 641 } 642 643 static void generic_suspend_enable_irqs(void) 644 { 645 local_irq_enable(); 646 } 647 648 /* Overrides the weak version in kernel/power/main.c */ 649 void arch_suspend_disable_irqs(void) 650 { 651 if (ppc_md.suspend_disable_irqs) 652 ppc_md.suspend_disable_irqs(); 653 generic_suspend_disable_irqs(); 654 } 655 656 /* Overrides the weak version in kernel/power/main.c */ 657 void arch_suspend_enable_irqs(void) 658 { 659 generic_suspend_enable_irqs(); 660 if (ppc_md.suspend_enable_irqs) 661 ppc_md.suspend_enable_irqs(); 662 } 663 #endif 664 665 /* 666 * Scheduler clock - returns current time in nanosec units. 667 * 668 * Note: mulhdu(a, b) (multiply high double unsigned) returns 669 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 670 * are 64-bit unsigned numbers. 671 */ 672 unsigned long long sched_clock(void) 673 { 674 if (__USE_RTC()) 675 return get_rtc(); 676 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 677 } 678 679 static int __init get_freq(char *name, int cells, unsigned long *val) 680 { 681 struct device_node *cpu; 682 const unsigned int *fp; 683 int found = 0; 684 685 /* The cpu node should have timebase and clock frequency properties */ 686 cpu = of_find_node_by_type(NULL, "cpu"); 687 688 if (cpu) { 689 fp = of_get_property(cpu, name, NULL); 690 if (fp) { 691 found = 1; 692 *val = of_read_ulong(fp, cells); 693 } 694 695 of_node_put(cpu); 696 } 697 698 return found; 699 } 700 701 /* should become __cpuinit when secondary_cpu_time_init also is */ 702 void start_cpu_decrementer(void) 703 { 704 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) 705 /* Clear any pending timer interrupts */ 706 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 707 708 /* Enable decrementer interrupt */ 709 mtspr(SPRN_TCR, TCR_DIE); 710 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */ 711 } 712 713 void __init generic_calibrate_decr(void) 714 { 715 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 716 717 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 718 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 719 720 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 721 "(not found)\n"); 722 } 723 724 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 725 726 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 727 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 728 729 printk(KERN_ERR "WARNING: Estimating processor frequency " 730 "(not found)\n"); 731 } 732 } 733 734 int update_persistent_clock(struct timespec now) 735 { 736 struct rtc_time tm; 737 738 if (!ppc_md.set_rtc_time) 739 return 0; 740 741 to_tm(now.tv_sec + 1 + timezone_offset, &tm); 742 tm.tm_year -= 1900; 743 tm.tm_mon -= 1; 744 745 return ppc_md.set_rtc_time(&tm); 746 } 747 748 static void __read_persistent_clock(struct timespec *ts) 749 { 750 struct rtc_time tm; 751 static int first = 1; 752 753 ts->tv_nsec = 0; 754 /* XXX this is a litle fragile but will work okay in the short term */ 755 if (first) { 756 first = 0; 757 if (ppc_md.time_init) 758 timezone_offset = ppc_md.time_init(); 759 760 /* get_boot_time() isn't guaranteed to be safe to call late */ 761 if (ppc_md.get_boot_time) { 762 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 763 return; 764 } 765 } 766 if (!ppc_md.get_rtc_time) { 767 ts->tv_sec = 0; 768 return; 769 } 770 ppc_md.get_rtc_time(&tm); 771 772 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, 773 tm.tm_hour, tm.tm_min, tm.tm_sec); 774 } 775 776 void read_persistent_clock(struct timespec *ts) 777 { 778 __read_persistent_clock(ts); 779 780 /* Sanitize it in case real time clock is set below EPOCH */ 781 if (ts->tv_sec < 0) { 782 ts->tv_sec = 0; 783 ts->tv_nsec = 0; 784 } 785 786 } 787 788 /* clocksource code */ 789 static cycle_t rtc_read(struct clocksource *cs) 790 { 791 return (cycle_t)get_rtc(); 792 } 793 794 static cycle_t timebase_read(struct clocksource *cs) 795 { 796 return (cycle_t)get_tb(); 797 } 798 799 void update_vsyscall(struct timespec *wall_time, struct timespec *wtm, 800 struct clocksource *clock, u32 mult) 801 { 802 u64 new_tb_to_xs, new_stamp_xsec; 803 u32 frac_sec; 804 805 if (clock != &clocksource_timebase) 806 return; 807 808 /* Make userspace gettimeofday spin until we're done. */ 809 ++vdso_data->tb_update_count; 810 smp_mb(); 811 812 /* XXX this assumes clock->shift == 22 */ 813 /* 4611686018 ~= 2^(20+64-22) / 1e9 */ 814 new_tb_to_xs = (u64) mult * 4611686018ULL; 815 new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC; 816 do_div(new_stamp_xsec, 1000000000); 817 new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC; 818 819 BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC); 820 /* this is tv_nsec / 1e9 as a 0.32 fraction */ 821 frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32; 822 823 /* 824 * tb_update_count is used to allow the userspace gettimeofday code 825 * to assure itself that it sees a consistent view of the tb_to_xs and 826 * stamp_xsec variables. It reads the tb_update_count, then reads 827 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If 828 * the two values of tb_update_count match and are even then the 829 * tb_to_xs and stamp_xsec values are consistent. If not, then it 830 * loops back and reads them again until this criteria is met. 831 * We expect the caller to have done the first increment of 832 * vdso_data->tb_update_count already. 833 */ 834 vdso_data->tb_orig_stamp = clock->cycle_last; 835 vdso_data->stamp_xsec = new_stamp_xsec; 836 vdso_data->tb_to_xs = new_tb_to_xs; 837 vdso_data->wtom_clock_sec = wtm->tv_sec; 838 vdso_data->wtom_clock_nsec = wtm->tv_nsec; 839 vdso_data->stamp_xtime = *wall_time; 840 vdso_data->stamp_sec_fraction = frac_sec; 841 smp_wmb(); 842 ++(vdso_data->tb_update_count); 843 } 844 845 void update_vsyscall_tz(void) 846 { 847 /* Make userspace gettimeofday spin until we're done. */ 848 ++vdso_data->tb_update_count; 849 smp_mb(); 850 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; 851 vdso_data->tz_dsttime = sys_tz.tz_dsttime; 852 smp_mb(); 853 ++vdso_data->tb_update_count; 854 } 855 856 static void __init clocksource_init(void) 857 { 858 struct clocksource *clock; 859 860 if (__USE_RTC()) 861 clock = &clocksource_rtc; 862 else 863 clock = &clocksource_timebase; 864 865 clock->mult = clocksource_hz2mult(tb_ticks_per_sec, clock->shift); 866 867 if (clocksource_register(clock)) { 868 printk(KERN_ERR "clocksource: %s is already registered\n", 869 clock->name); 870 return; 871 } 872 873 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 874 clock->name, clock->mult, clock->shift); 875 } 876 877 static int decrementer_set_next_event(unsigned long evt, 878 struct clock_event_device *dev) 879 { 880 __get_cpu_var(decrementers).next_tb = get_tb_or_rtc() + evt; 881 set_dec(evt); 882 return 0; 883 } 884 885 static void decrementer_set_mode(enum clock_event_mode mode, 886 struct clock_event_device *dev) 887 { 888 if (mode != CLOCK_EVT_MODE_ONESHOT) 889 decrementer_set_next_event(DECREMENTER_MAX, dev); 890 } 891 892 static inline uint64_t div_sc64(unsigned long ticks, unsigned long nsec, 893 int shift) 894 { 895 uint64_t tmp = ((uint64_t)ticks) << shift; 896 897 do_div(tmp, nsec); 898 return tmp; 899 } 900 901 static void __init setup_clockevent_multiplier(unsigned long hz) 902 { 903 u64 mult, shift = 32; 904 905 while (1) { 906 mult = div_sc64(hz, NSEC_PER_SEC, shift); 907 if (mult && (mult >> 32UL) == 0UL) 908 break; 909 910 shift--; 911 } 912 913 decrementer_clockevent.shift = shift; 914 decrementer_clockevent.mult = mult; 915 } 916 917 static void register_decrementer_clockevent(int cpu) 918 { 919 struct clock_event_device *dec = &per_cpu(decrementers, cpu).event; 920 921 *dec = decrementer_clockevent; 922 dec->cpumask = cpumask_of(cpu); 923 924 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 925 dec->name, dec->mult, dec->shift, cpu); 926 927 clockevents_register_device(dec); 928 } 929 930 static void __init init_decrementer_clockevent(void) 931 { 932 int cpu = smp_processor_id(); 933 934 setup_clockevent_multiplier(ppc_tb_freq); 935 decrementer_clockevent.max_delta_ns = 936 clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent); 937 decrementer_clockevent.min_delta_ns = 938 clockevent_delta2ns(2, &decrementer_clockevent); 939 940 register_decrementer_clockevent(cpu); 941 } 942 943 void secondary_cpu_time_init(void) 944 { 945 /* Start the decrementer on CPUs that have manual control 946 * such as BookE 947 */ 948 start_cpu_decrementer(); 949 950 /* FIME: Should make unrelatred change to move snapshot_timebase 951 * call here ! */ 952 register_decrementer_clockevent(smp_processor_id()); 953 } 954 955 /* This function is only called on the boot processor */ 956 void __init time_init(void) 957 { 958 struct div_result res; 959 u64 scale; 960 unsigned shift; 961 962 if (__USE_RTC()) { 963 /* 601 processor: dec counts down by 128 every 128ns */ 964 ppc_tb_freq = 1000000000; 965 } else { 966 /* Normal PowerPC with timebase register */ 967 ppc_md.calibrate_decr(); 968 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 969 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 970 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 971 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 972 } 973 974 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 975 tb_ticks_per_sec = ppc_tb_freq; 976 tb_ticks_per_usec = ppc_tb_freq / 1000000; 977 calc_cputime_factors(); 978 setup_cputime_one_jiffy(); 979 980 /* 981 * Compute scale factor for sched_clock. 982 * The calibrate_decr() function has set tb_ticks_per_sec, 983 * which is the timebase frequency. 984 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 985 * the 128-bit result as a 64.64 fixed-point number. 986 * We then shift that number right until it is less than 1.0, 987 * giving us the scale factor and shift count to use in 988 * sched_clock(). 989 */ 990 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 991 scale = res.result_low; 992 for (shift = 0; res.result_high != 0; ++shift) { 993 scale = (scale >> 1) | (res.result_high << 63); 994 res.result_high >>= 1; 995 } 996 tb_to_ns_scale = scale; 997 tb_to_ns_shift = shift; 998 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 999 boot_tb = get_tb_or_rtc(); 1000 1001 /* If platform provided a timezone (pmac), we correct the time */ 1002 if (timezone_offset) { 1003 sys_tz.tz_minuteswest = -timezone_offset / 60; 1004 sys_tz.tz_dsttime = 0; 1005 } 1006 1007 vdso_data->tb_update_count = 0; 1008 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 1009 1010 /* Start the decrementer on CPUs that have manual control 1011 * such as BookE 1012 */ 1013 start_cpu_decrementer(); 1014 1015 /* Register the clocksource, if we're not running on iSeries */ 1016 if (!firmware_has_feature(FW_FEATURE_ISERIES)) 1017 clocksource_init(); 1018 1019 init_decrementer_clockevent(); 1020 } 1021 1022 1023 #define FEBRUARY 2 1024 #define STARTOFTIME 1970 1025 #define SECDAY 86400L 1026 #define SECYR (SECDAY * 365) 1027 #define leapyear(year) ((year) % 4 == 0 && \ 1028 ((year) % 100 != 0 || (year) % 400 == 0)) 1029 #define days_in_year(a) (leapyear(a) ? 366 : 365) 1030 #define days_in_month(a) (month_days[(a) - 1]) 1031 1032 static int month_days[12] = { 1033 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 1034 }; 1035 1036 /* 1037 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) 1038 */ 1039 void GregorianDay(struct rtc_time * tm) 1040 { 1041 int leapsToDate; 1042 int lastYear; 1043 int day; 1044 int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; 1045 1046 lastYear = tm->tm_year - 1; 1047 1048 /* 1049 * Number of leap corrections to apply up to end of last year 1050 */ 1051 leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400; 1052 1053 /* 1054 * This year is a leap year if it is divisible by 4 except when it is 1055 * divisible by 100 unless it is divisible by 400 1056 * 1057 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was 1058 */ 1059 day = tm->tm_mon > 2 && leapyear(tm->tm_year); 1060 1061 day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + 1062 tm->tm_mday; 1063 1064 tm->tm_wday = day % 7; 1065 } 1066 1067 void to_tm(int tim, struct rtc_time * tm) 1068 { 1069 register int i; 1070 register long hms, day; 1071 1072 day = tim / SECDAY; 1073 hms = tim % SECDAY; 1074 1075 /* Hours, minutes, seconds are easy */ 1076 tm->tm_hour = hms / 3600; 1077 tm->tm_min = (hms % 3600) / 60; 1078 tm->tm_sec = (hms % 3600) % 60; 1079 1080 /* Number of years in days */ 1081 for (i = STARTOFTIME; day >= days_in_year(i); i++) 1082 day -= days_in_year(i); 1083 tm->tm_year = i; 1084 1085 /* Number of months in days left */ 1086 if (leapyear(tm->tm_year)) 1087 days_in_month(FEBRUARY) = 29; 1088 for (i = 1; day >= days_in_month(i); i++) 1089 day -= days_in_month(i); 1090 days_in_month(FEBRUARY) = 28; 1091 tm->tm_mon = i; 1092 1093 /* Days are what is left over (+1) from all that. */ 1094 tm->tm_mday = day + 1; 1095 1096 /* 1097 * Determine the day of week 1098 */ 1099 GregorianDay(tm); 1100 } 1101 1102 /* 1103 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 1104 * result. 1105 */ 1106 void div128_by_32(u64 dividend_high, u64 dividend_low, 1107 unsigned divisor, struct div_result *dr) 1108 { 1109 unsigned long a, b, c, d; 1110 unsigned long w, x, y, z; 1111 u64 ra, rb, rc; 1112 1113 a = dividend_high >> 32; 1114 b = dividend_high & 0xffffffff; 1115 c = dividend_low >> 32; 1116 d = dividend_low & 0xffffffff; 1117 1118 w = a / divisor; 1119 ra = ((u64)(a - (w * divisor)) << 32) + b; 1120 1121 rb = ((u64) do_div(ra, divisor) << 32) + c; 1122 x = ra; 1123 1124 rc = ((u64) do_div(rb, divisor) << 32) + d; 1125 y = rb; 1126 1127 do_div(rc, divisor); 1128 z = rc; 1129 1130 dr->result_high = ((u64)w << 32) + x; 1131 dr->result_low = ((u64)y << 32) + z; 1132 1133 } 1134 1135 /* We don't need to calibrate delay, we use the CPU timebase for that */ 1136 void calibrate_delay(void) 1137 { 1138 /* Some generic code (such as spinlock debug) use loops_per_jiffy 1139 * as the number of __delay(1) in a jiffy, so make it so 1140 */ 1141 loops_per_jiffy = tb_ticks_per_jiffy; 1142 } 1143 1144 static int __init rtc_init(void) 1145 { 1146 struct platform_device *pdev; 1147 1148 if (!ppc_md.get_rtc_time) 1149 return -ENODEV; 1150 1151 pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0); 1152 if (IS_ERR(pdev)) 1153 return PTR_ERR(pdev); 1154 1155 return 0; 1156 } 1157 1158 module_init(rtc_init); 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