1 /* 2 * Common time routines among all ppc machines. 3 * 4 * Written by Cort Dougan (cort@cs.nmt.edu) to merge 5 * Paul Mackerras' version and mine for PReP and Pmac. 6 * MPC8xx/MBX changes by Dan Malek (dmalek@jlc.net). 7 * Converted for 64-bit by Mike Corrigan (mikejc@us.ibm.com) 8 * 9 * First round of bugfixes by Gabriel Paubert (paubert@iram.es) 10 * to make clock more stable (2.4.0-test5). The only thing 11 * that this code assumes is that the timebases have been synchronized 12 * by firmware on SMP and are never stopped (never do sleep 13 * on SMP then, nap and doze are OK). 14 * 15 * Speeded up do_gettimeofday by getting rid of references to 16 * xtime (which required locks for consistency). (mikejc@us.ibm.com) 17 * 18 * TODO (not necessarily in this file): 19 * - improve precision and reproducibility of timebase frequency 20 * measurement at boot time. (for iSeries, we calibrate the timebase 21 * against the Titan chip's clock.) 22 * - for astronomical applications: add a new function to get 23 * non ambiguous timestamps even around leap seconds. This needs 24 * a new timestamp format and a good name. 25 * 26 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 27 * "A Kernel Model for Precision Timekeeping" by Dave Mills 28 * 29 * This program is free software; you can redistribute it and/or 30 * modify it under the terms of the GNU General Public License 31 * as published by the Free Software Foundation; either version 32 * 2 of the License, or (at your option) any later version. 33 */ 34 35 #include <linux/errno.h> 36 #include <linux/module.h> 37 #include <linux/sched.h> 38 #include <linux/kernel.h> 39 #include <linux/param.h> 40 #include <linux/string.h> 41 #include <linux/mm.h> 42 #include <linux/interrupt.h> 43 #include <linux/timex.h> 44 #include <linux/kernel_stat.h> 45 #include <linux/time.h> 46 #include <linux/init.h> 47 #include <linux/profile.h> 48 #include <linux/cpu.h> 49 #include <linux/security.h> 50 #include <linux/percpu.h> 51 #include <linux/rtc.h> 52 #include <linux/jiffies.h> 53 #include <linux/posix-timers.h> 54 #include <linux/irq.h> 55 #include <linux/delay.h> 56 #include <linux/irq_work.h> 57 #include <asm/trace.h> 58 59 #include <asm/io.h> 60 #include <asm/processor.h> 61 #include <asm/nvram.h> 62 #include <asm/cache.h> 63 #include <asm/machdep.h> 64 #include <asm/uaccess.h> 65 #include <asm/time.h> 66 #include <asm/prom.h> 67 #include <asm/irq.h> 68 #include <asm/div64.h> 69 #include <asm/smp.h> 70 #include <asm/vdso_datapage.h> 71 #include <asm/firmware.h> 72 #include <asm/cputime.h> 73 #ifdef CONFIG_PPC_ISERIES 74 #include <asm/iseries/it_lp_queue.h> 75 #include <asm/iseries/hv_call_xm.h> 76 #endif 77 78 /* powerpc clocksource/clockevent code */ 79 80 #include <linux/clockchips.h> 81 #include <linux/clocksource.h> 82 83 static cycle_t rtc_read(struct clocksource *); 84 static struct clocksource clocksource_rtc = { 85 .name = "rtc", 86 .rating = 400, 87 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 88 .mask = CLOCKSOURCE_MASK(64), 89 .shift = 22, 90 .mult = 0, /* To be filled in */ 91 .read = rtc_read, 92 }; 93 94 static cycle_t timebase_read(struct clocksource *); 95 static struct clocksource clocksource_timebase = { 96 .name = "timebase", 97 .rating = 400, 98 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 99 .mask = CLOCKSOURCE_MASK(64), 100 .shift = 22, 101 .mult = 0, /* To be filled in */ 102 .read = timebase_read, 103 }; 104 105 #define DECREMENTER_MAX 0x7fffffff 106 107 static int decrementer_set_next_event(unsigned long evt, 108 struct clock_event_device *dev); 109 static void decrementer_set_mode(enum clock_event_mode mode, 110 struct clock_event_device *dev); 111 112 static struct clock_event_device decrementer_clockevent = { 113 .name = "decrementer", 114 .rating = 200, 115 .shift = 0, /* To be filled in */ 116 .mult = 0, /* To be filled in */ 117 .irq = 0, 118 .set_next_event = decrementer_set_next_event, 119 .set_mode = decrementer_set_mode, 120 .features = CLOCK_EVT_FEAT_ONESHOT, 121 }; 122 123 struct decrementer_clock { 124 struct clock_event_device event; 125 u64 next_tb; 126 }; 127 128 static DEFINE_PER_CPU(struct decrementer_clock, decrementers); 129 130 #ifdef CONFIG_PPC_ISERIES 131 static unsigned long __initdata iSeries_recal_titan; 132 static signed long __initdata iSeries_recal_tb; 133 134 /* Forward declaration is only needed for iSereis compiles */ 135 static void __init clocksource_init(void); 136 #endif 137 138 #define XSEC_PER_SEC (1024*1024) 139 140 #ifdef CONFIG_PPC64 141 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) 142 #else 143 /* compute ((xsec << 12) * max) >> 32 */ 144 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) 145 #endif 146 147 unsigned long tb_ticks_per_jiffy; 148 unsigned long tb_ticks_per_usec = 100; /* sane default */ 149 EXPORT_SYMBOL(tb_ticks_per_usec); 150 unsigned long tb_ticks_per_sec; 151 EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ 152 153 DEFINE_SPINLOCK(rtc_lock); 154 EXPORT_SYMBOL_GPL(rtc_lock); 155 156 static u64 tb_to_ns_scale __read_mostly; 157 static unsigned tb_to_ns_shift __read_mostly; 158 static u64 boot_tb __read_mostly; 159 160 extern struct timezone sys_tz; 161 static long timezone_offset; 162 163 unsigned long ppc_proc_freq; 164 EXPORT_SYMBOL_GPL(ppc_proc_freq); 165 unsigned long ppc_tb_freq; 166 EXPORT_SYMBOL_GPL(ppc_tb_freq); 167 168 #ifdef CONFIG_VIRT_CPU_ACCOUNTING 169 /* 170 * Factors for converting from cputime_t (timebase ticks) to 171 * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds). 172 * These are all stored as 0.64 fixed-point binary fractions. 173 */ 174 u64 __cputime_jiffies_factor; 175 EXPORT_SYMBOL(__cputime_jiffies_factor); 176 u64 __cputime_msec_factor; 177 EXPORT_SYMBOL(__cputime_msec_factor); 178 u64 __cputime_sec_factor; 179 EXPORT_SYMBOL(__cputime_sec_factor); 180 u64 __cputime_clockt_factor; 181 EXPORT_SYMBOL(__cputime_clockt_factor); 182 DEFINE_PER_CPU(unsigned long, cputime_last_delta); 183 DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta); 184 185 cputime_t cputime_one_jiffy; 186 187 void (*dtl_consumer)(struct dtl_entry *, u64); 188 189 static void calc_cputime_factors(void) 190 { 191 struct div_result res; 192 193 div128_by_32(HZ, 0, tb_ticks_per_sec, &res); 194 __cputime_jiffies_factor = res.result_low; 195 div128_by_32(1000, 0, tb_ticks_per_sec, &res); 196 __cputime_msec_factor = res.result_low; 197 div128_by_32(1, 0, tb_ticks_per_sec, &res); 198 __cputime_sec_factor = res.result_low; 199 div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res); 200 __cputime_clockt_factor = res.result_low; 201 } 202 203 /* 204 * Read the SPURR on systems that have it, otherwise the PURR, 205 * or if that doesn't exist return the timebase value passed in. 206 */ 207 static u64 read_spurr(u64 tb) 208 { 209 if (cpu_has_feature(CPU_FTR_SPURR)) 210 return mfspr(SPRN_SPURR); 211 if (cpu_has_feature(CPU_FTR_PURR)) 212 return mfspr(SPRN_PURR); 213 return tb; 214 } 215 216 #ifdef CONFIG_PPC_SPLPAR 217 218 /* 219 * Scan the dispatch trace log and count up the stolen time. 220 * Should be called with interrupts disabled. 221 */ 222 static u64 scan_dispatch_log(u64 stop_tb) 223 { 224 u64 i = local_paca->dtl_ridx; 225 struct dtl_entry *dtl = local_paca->dtl_curr; 226 struct dtl_entry *dtl_end = local_paca->dispatch_log_end; 227 struct lppaca *vpa = local_paca->lppaca_ptr; 228 u64 tb_delta; 229 u64 stolen = 0; 230 u64 dtb; 231 232 if (i == vpa->dtl_idx) 233 return 0; 234 while (i < vpa->dtl_idx) { 235 if (dtl_consumer) 236 dtl_consumer(dtl, i); 237 dtb = dtl->timebase; 238 tb_delta = dtl->enqueue_to_dispatch_time + 239 dtl->ready_to_enqueue_time; 240 barrier(); 241 if (i + N_DISPATCH_LOG < vpa->dtl_idx) { 242 /* buffer has overflowed */ 243 i = vpa->dtl_idx - N_DISPATCH_LOG; 244 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG); 245 continue; 246 } 247 if (dtb > stop_tb) 248 break; 249 stolen += tb_delta; 250 ++i; 251 ++dtl; 252 if (dtl == dtl_end) 253 dtl = local_paca->dispatch_log; 254 } 255 local_paca->dtl_ridx = i; 256 local_paca->dtl_curr = dtl; 257 return stolen; 258 } 259 260 /* 261 * Accumulate stolen time by scanning the dispatch trace log. 262 * Called on entry from user mode. 263 */ 264 void accumulate_stolen_time(void) 265 { 266 u64 sst, ust; 267 268 u8 save_soft_enabled = local_paca->soft_enabled; 269 u8 save_hard_enabled = local_paca->hard_enabled; 270 271 /* We are called early in the exception entry, before 272 * soft/hard_enabled are sync'ed to the expected state 273 * for the exception. We are hard disabled but the PACA 274 * needs to reflect that so various debug stuff doesn't 275 * complain 276 */ 277 local_paca->soft_enabled = 0; 278 local_paca->hard_enabled = 0; 279 280 sst = scan_dispatch_log(local_paca->starttime_user); 281 ust = scan_dispatch_log(local_paca->starttime); 282 local_paca->system_time -= sst; 283 local_paca->user_time -= ust; 284 local_paca->stolen_time += ust + sst; 285 286 local_paca->soft_enabled = save_soft_enabled; 287 local_paca->hard_enabled = save_hard_enabled; 288 } 289 290 static inline u64 calculate_stolen_time(u64 stop_tb) 291 { 292 u64 stolen = 0; 293 294 if (get_paca()->dtl_ridx != get_paca()->lppaca_ptr->dtl_idx) { 295 stolen = scan_dispatch_log(stop_tb); 296 get_paca()->system_time -= stolen; 297 } 298 299 stolen += get_paca()->stolen_time; 300 get_paca()->stolen_time = 0; 301 return stolen; 302 } 303 304 #else /* CONFIG_PPC_SPLPAR */ 305 static inline u64 calculate_stolen_time(u64 stop_tb) 306 { 307 return 0; 308 } 309 310 #endif /* CONFIG_PPC_SPLPAR */ 311 312 /* 313 * Account time for a transition between system, hard irq 314 * or soft irq state. 315 */ 316 void account_system_vtime(struct task_struct *tsk) 317 { 318 u64 now, nowscaled, delta, deltascaled; 319 unsigned long flags; 320 u64 stolen, udelta, sys_scaled, user_scaled; 321 322 local_irq_save(flags); 323 now = mftb(); 324 nowscaled = read_spurr(now); 325 get_paca()->system_time += now - get_paca()->starttime; 326 get_paca()->starttime = now; 327 deltascaled = nowscaled - get_paca()->startspurr; 328 get_paca()->startspurr = nowscaled; 329 330 stolen = calculate_stolen_time(now); 331 332 delta = get_paca()->system_time; 333 get_paca()->system_time = 0; 334 udelta = get_paca()->user_time - get_paca()->utime_sspurr; 335 get_paca()->utime_sspurr = get_paca()->user_time; 336 337 /* 338 * Because we don't read the SPURR on every kernel entry/exit, 339 * deltascaled includes both user and system SPURR ticks. 340 * Apportion these ticks to system SPURR ticks and user 341 * SPURR ticks in the same ratio as the system time (delta) 342 * and user time (udelta) values obtained from the timebase 343 * over the same interval. The system ticks get accounted here; 344 * the user ticks get saved up in paca->user_time_scaled to be 345 * used by account_process_tick. 346 */ 347 sys_scaled = delta; 348 user_scaled = udelta; 349 if (deltascaled != delta + udelta) { 350 if (udelta) { 351 sys_scaled = deltascaled * delta / (delta + udelta); 352 user_scaled = deltascaled - sys_scaled; 353 } else { 354 sys_scaled = deltascaled; 355 } 356 } 357 get_paca()->user_time_scaled += user_scaled; 358 359 if (in_irq() || idle_task(smp_processor_id()) != tsk) { 360 account_system_time(tsk, 0, delta, sys_scaled); 361 if (stolen) 362 account_steal_time(stolen); 363 } else { 364 account_idle_time(delta + stolen); 365 } 366 local_irq_restore(flags); 367 } 368 EXPORT_SYMBOL_GPL(account_system_vtime); 369 370 /* 371 * Transfer the user and system times accumulated in the paca 372 * by the exception entry and exit code to the generic process 373 * user and system time records. 374 * Must be called with interrupts disabled. 375 * Assumes that account_system_vtime() has been called recently 376 * (i.e. since the last entry from usermode) so that 377 * get_paca()->user_time_scaled is up to date. 378 */ 379 void account_process_tick(struct task_struct *tsk, int user_tick) 380 { 381 cputime_t utime, utimescaled; 382 383 utime = get_paca()->user_time; 384 utimescaled = get_paca()->user_time_scaled; 385 get_paca()->user_time = 0; 386 get_paca()->user_time_scaled = 0; 387 get_paca()->utime_sspurr = 0; 388 account_user_time(tsk, utime, utimescaled); 389 } 390 391 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */ 392 #define calc_cputime_factors() 393 #endif 394 395 void __delay(unsigned long loops) 396 { 397 unsigned long start; 398 int diff; 399 400 if (__USE_RTC()) { 401 start = get_rtcl(); 402 do { 403 /* the RTCL register wraps at 1000000000 */ 404 diff = get_rtcl() - start; 405 if (diff < 0) 406 diff += 1000000000; 407 } while (diff < loops); 408 } else { 409 start = get_tbl(); 410 while (get_tbl() - start < loops) 411 HMT_low(); 412 HMT_medium(); 413 } 414 } 415 EXPORT_SYMBOL(__delay); 416 417 void udelay(unsigned long usecs) 418 { 419 __delay(tb_ticks_per_usec * usecs); 420 } 421 EXPORT_SYMBOL(udelay); 422 423 #ifdef CONFIG_SMP 424 unsigned long profile_pc(struct pt_regs *regs) 425 { 426 unsigned long pc = instruction_pointer(regs); 427 428 if (in_lock_functions(pc)) 429 return regs->link; 430 431 return pc; 432 } 433 EXPORT_SYMBOL(profile_pc); 434 #endif 435 436 #ifdef CONFIG_PPC_ISERIES 437 438 /* 439 * This function recalibrates the timebase based on the 49-bit time-of-day 440 * value in the Titan chip. The Titan is much more accurate than the value 441 * returned by the service processor for the timebase frequency. 442 */ 443 444 static int __init iSeries_tb_recal(void) 445 { 446 unsigned long titan, tb; 447 448 /* Make sure we only run on iSeries */ 449 if (!firmware_has_feature(FW_FEATURE_ISERIES)) 450 return -ENODEV; 451 452 tb = get_tb(); 453 titan = HvCallXm_loadTod(); 454 if ( iSeries_recal_titan ) { 455 unsigned long tb_ticks = tb - iSeries_recal_tb; 456 unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12; 457 unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec; 458 unsigned long new_tb_ticks_per_jiffy = 459 DIV_ROUND_CLOSEST(new_tb_ticks_per_sec, HZ); 460 long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy; 461 char sign = '+'; 462 /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */ 463 new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ; 464 465 if ( tick_diff < 0 ) { 466 tick_diff = -tick_diff; 467 sign = '-'; 468 } 469 if ( tick_diff ) { 470 if ( tick_diff < tb_ticks_per_jiffy/25 ) { 471 printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n", 472 new_tb_ticks_per_jiffy, sign, tick_diff ); 473 tb_ticks_per_jiffy = new_tb_ticks_per_jiffy; 474 tb_ticks_per_sec = new_tb_ticks_per_sec; 475 calc_cputime_factors(); 476 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 477 setup_cputime_one_jiffy(); 478 } 479 else { 480 printk( "Titan recalibrate: FAILED (difference > 4 percent)\n" 481 " new tb_ticks_per_jiffy = %lu\n" 482 " old tb_ticks_per_jiffy = %lu\n", 483 new_tb_ticks_per_jiffy, tb_ticks_per_jiffy ); 484 } 485 } 486 } 487 iSeries_recal_titan = titan; 488 iSeries_recal_tb = tb; 489 490 /* Called here as now we know accurate values for the timebase */ 491 clocksource_init(); 492 return 0; 493 } 494 late_initcall(iSeries_tb_recal); 495 496 /* Called from platform early init */ 497 void __init iSeries_time_init_early(void) 498 { 499 iSeries_recal_tb = get_tb(); 500 iSeries_recal_titan = HvCallXm_loadTod(); 501 } 502 #endif /* CONFIG_PPC_ISERIES */ 503 504 #ifdef CONFIG_IRQ_WORK 505 506 /* 507 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable... 508 */ 509 #ifdef CONFIG_PPC64 510 static inline unsigned long test_irq_work_pending(void) 511 { 512 unsigned long x; 513 514 asm volatile("lbz %0,%1(13)" 515 : "=r" (x) 516 : "i" (offsetof(struct paca_struct, irq_work_pending))); 517 return x; 518 } 519 520 static inline void set_irq_work_pending_flag(void) 521 { 522 asm volatile("stb %0,%1(13)" : : 523 "r" (1), 524 "i" (offsetof(struct paca_struct, irq_work_pending))); 525 } 526 527 static inline void clear_irq_work_pending(void) 528 { 529 asm volatile("stb %0,%1(13)" : : 530 "r" (0), 531 "i" (offsetof(struct paca_struct, irq_work_pending))); 532 } 533 534 #else /* 32-bit */ 535 536 DEFINE_PER_CPU(u8, irq_work_pending); 537 538 #define set_irq_work_pending_flag() __get_cpu_var(irq_work_pending) = 1 539 #define test_irq_work_pending() __get_cpu_var(irq_work_pending) 540 #define clear_irq_work_pending() __get_cpu_var(irq_work_pending) = 0 541 542 #endif /* 32 vs 64 bit */ 543 544 void set_irq_work_pending(void) 545 { 546 preempt_disable(); 547 set_irq_work_pending_flag(); 548 set_dec(1); 549 preempt_enable(); 550 } 551 552 #else /* CONFIG_IRQ_WORK */ 553 554 #define test_irq_work_pending() 0 555 #define clear_irq_work_pending() 556 557 #endif /* CONFIG_IRQ_WORK */ 558 559 /* 560 * For iSeries shared processors, we have to let the hypervisor 561 * set the hardware decrementer. We set a virtual decrementer 562 * in the lppaca and call the hypervisor if the virtual 563 * decrementer is less than the current value in the hardware 564 * decrementer. (almost always the new decrementer value will 565 * be greater than the current hardware decementer so the hypervisor 566 * call will not be needed) 567 */ 568 569 /* 570 * timer_interrupt - gets called when the decrementer overflows, 571 * with interrupts disabled. 572 */ 573 void timer_interrupt(struct pt_regs * regs) 574 { 575 struct pt_regs *old_regs; 576 struct decrementer_clock *decrementer = &__get_cpu_var(decrementers); 577 struct clock_event_device *evt = &decrementer->event; 578 u64 now; 579 580 trace_timer_interrupt_entry(regs); 581 582 __get_cpu_var(irq_stat).timer_irqs++; 583 584 /* Ensure a positive value is written to the decrementer, or else 585 * some CPUs will continuue to take decrementer exceptions */ 586 set_dec(DECREMENTER_MAX); 587 588 #if defined(CONFIG_PPC32) && defined(CONFIG_PMAC) 589 if (atomic_read(&ppc_n_lost_interrupts) != 0) 590 do_IRQ(regs); 591 #endif 592 593 old_regs = set_irq_regs(regs); 594 irq_enter(); 595 596 if (test_irq_work_pending()) { 597 clear_irq_work_pending(); 598 irq_work_run(); 599 } 600 601 #ifdef CONFIG_PPC_ISERIES 602 if (firmware_has_feature(FW_FEATURE_ISERIES)) 603 get_lppaca()->int_dword.fields.decr_int = 0; 604 #endif 605 606 now = get_tb_or_rtc(); 607 if (now >= decrementer->next_tb) { 608 decrementer->next_tb = ~(u64)0; 609 if (evt->event_handler) 610 evt->event_handler(evt); 611 } else { 612 now = decrementer->next_tb - now; 613 if (now <= DECREMENTER_MAX) 614 set_dec((int)now); 615 } 616 617 #ifdef CONFIG_PPC_ISERIES 618 if (firmware_has_feature(FW_FEATURE_ISERIES) && hvlpevent_is_pending()) 619 process_hvlpevents(); 620 #endif 621 622 #ifdef CONFIG_PPC64 623 /* collect purr register values often, for accurate calculations */ 624 if (firmware_has_feature(FW_FEATURE_SPLPAR)) { 625 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); 626 cu->current_tb = mfspr(SPRN_PURR); 627 } 628 #endif 629 630 irq_exit(); 631 set_irq_regs(old_regs); 632 633 trace_timer_interrupt_exit(regs); 634 } 635 636 #ifdef CONFIG_SUSPEND 637 static void generic_suspend_disable_irqs(void) 638 { 639 /* Disable the decrementer, so that it doesn't interfere 640 * with suspending. 641 */ 642 643 set_dec(0x7fffffff); 644 local_irq_disable(); 645 set_dec(0x7fffffff); 646 } 647 648 static void generic_suspend_enable_irqs(void) 649 { 650 local_irq_enable(); 651 } 652 653 /* Overrides the weak version in kernel/power/main.c */ 654 void arch_suspend_disable_irqs(void) 655 { 656 if (ppc_md.suspend_disable_irqs) 657 ppc_md.suspend_disable_irqs(); 658 generic_suspend_disable_irqs(); 659 } 660 661 /* Overrides the weak version in kernel/power/main.c */ 662 void arch_suspend_enable_irqs(void) 663 { 664 generic_suspend_enable_irqs(); 665 if (ppc_md.suspend_enable_irqs) 666 ppc_md.suspend_enable_irqs(); 667 } 668 #endif 669 670 /* 671 * Scheduler clock - returns current time in nanosec units. 672 * 673 * Note: mulhdu(a, b) (multiply high double unsigned) returns 674 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 675 * are 64-bit unsigned numbers. 676 */ 677 unsigned long long sched_clock(void) 678 { 679 if (__USE_RTC()) 680 return get_rtc(); 681 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 682 } 683 684 static int __init get_freq(char *name, int cells, unsigned long *val) 685 { 686 struct device_node *cpu; 687 const unsigned int *fp; 688 int found = 0; 689 690 /* The cpu node should have timebase and clock frequency properties */ 691 cpu = of_find_node_by_type(NULL, "cpu"); 692 693 if (cpu) { 694 fp = of_get_property(cpu, name, NULL); 695 if (fp) { 696 found = 1; 697 *val = of_read_ulong(fp, cells); 698 } 699 700 of_node_put(cpu); 701 } 702 703 return found; 704 } 705 706 /* should become __cpuinit when secondary_cpu_time_init also is */ 707 void start_cpu_decrementer(void) 708 { 709 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) 710 /* Clear any pending timer interrupts */ 711 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 712 713 /* Enable decrementer interrupt */ 714 mtspr(SPRN_TCR, TCR_DIE); 715 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */ 716 } 717 718 void __init generic_calibrate_decr(void) 719 { 720 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 721 722 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 723 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 724 725 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 726 "(not found)\n"); 727 } 728 729 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 730 731 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 732 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 733 734 printk(KERN_ERR "WARNING: Estimating processor frequency " 735 "(not found)\n"); 736 } 737 } 738 739 int update_persistent_clock(struct timespec now) 740 { 741 struct rtc_time tm; 742 743 if (!ppc_md.set_rtc_time) 744 return 0; 745 746 to_tm(now.tv_sec + 1 + timezone_offset, &tm); 747 tm.tm_year -= 1900; 748 tm.tm_mon -= 1; 749 750 return ppc_md.set_rtc_time(&tm); 751 } 752 753 static void __read_persistent_clock(struct timespec *ts) 754 { 755 struct rtc_time tm; 756 static int first = 1; 757 758 ts->tv_nsec = 0; 759 /* XXX this is a litle fragile but will work okay in the short term */ 760 if (first) { 761 first = 0; 762 if (ppc_md.time_init) 763 timezone_offset = ppc_md.time_init(); 764 765 /* get_boot_time() isn't guaranteed to be safe to call late */ 766 if (ppc_md.get_boot_time) { 767 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 768 return; 769 } 770 } 771 if (!ppc_md.get_rtc_time) { 772 ts->tv_sec = 0; 773 return; 774 } 775 ppc_md.get_rtc_time(&tm); 776 777 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, 778 tm.tm_hour, tm.tm_min, tm.tm_sec); 779 } 780 781 void read_persistent_clock(struct timespec *ts) 782 { 783 __read_persistent_clock(ts); 784 785 /* Sanitize it in case real time clock is set below EPOCH */ 786 if (ts->tv_sec < 0) { 787 ts->tv_sec = 0; 788 ts->tv_nsec = 0; 789 } 790 791 } 792 793 /* clocksource code */ 794 static cycle_t rtc_read(struct clocksource *cs) 795 { 796 return (cycle_t)get_rtc(); 797 } 798 799 static cycle_t timebase_read(struct clocksource *cs) 800 { 801 return (cycle_t)get_tb(); 802 } 803 804 void update_vsyscall(struct timespec *wall_time, struct timespec *wtm, 805 struct clocksource *clock, u32 mult) 806 { 807 u64 new_tb_to_xs, new_stamp_xsec; 808 u32 frac_sec; 809 810 if (clock != &clocksource_timebase) 811 return; 812 813 /* Make userspace gettimeofday spin until we're done. */ 814 ++vdso_data->tb_update_count; 815 smp_mb(); 816 817 /* XXX this assumes clock->shift == 22 */ 818 /* 4611686018 ~= 2^(20+64-22) / 1e9 */ 819 new_tb_to_xs = (u64) mult * 4611686018ULL; 820 new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC; 821 do_div(new_stamp_xsec, 1000000000); 822 new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC; 823 824 BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC); 825 /* this is tv_nsec / 1e9 as a 0.32 fraction */ 826 frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32; 827 828 /* 829 * tb_update_count is used to allow the userspace gettimeofday code 830 * to assure itself that it sees a consistent view of the tb_to_xs and 831 * stamp_xsec variables. It reads the tb_update_count, then reads 832 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If 833 * the two values of tb_update_count match and are even then the 834 * tb_to_xs and stamp_xsec values are consistent. If not, then it 835 * loops back and reads them again until this criteria is met. 836 * We expect the caller to have done the first increment of 837 * vdso_data->tb_update_count already. 838 */ 839 vdso_data->tb_orig_stamp = clock->cycle_last; 840 vdso_data->stamp_xsec = new_stamp_xsec; 841 vdso_data->tb_to_xs = new_tb_to_xs; 842 vdso_data->wtom_clock_sec = wtm->tv_sec; 843 vdso_data->wtom_clock_nsec = wtm->tv_nsec; 844 vdso_data->stamp_xtime = *wall_time; 845 vdso_data->stamp_sec_fraction = frac_sec; 846 smp_wmb(); 847 ++(vdso_data->tb_update_count); 848 } 849 850 void update_vsyscall_tz(void) 851 { 852 /* Make userspace gettimeofday spin until we're done. */ 853 ++vdso_data->tb_update_count; 854 smp_mb(); 855 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; 856 vdso_data->tz_dsttime = sys_tz.tz_dsttime; 857 smp_mb(); 858 ++vdso_data->tb_update_count; 859 } 860 861 static void __init clocksource_init(void) 862 { 863 struct clocksource *clock; 864 865 if (__USE_RTC()) 866 clock = &clocksource_rtc; 867 else 868 clock = &clocksource_timebase; 869 870 clock->mult = clocksource_hz2mult(tb_ticks_per_sec, clock->shift); 871 872 if (clocksource_register(clock)) { 873 printk(KERN_ERR "clocksource: %s is already registered\n", 874 clock->name); 875 return; 876 } 877 878 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 879 clock->name, clock->mult, clock->shift); 880 } 881 882 static int decrementer_set_next_event(unsigned long evt, 883 struct clock_event_device *dev) 884 { 885 __get_cpu_var(decrementers).next_tb = get_tb_or_rtc() + evt; 886 set_dec(evt); 887 return 0; 888 } 889 890 static void decrementer_set_mode(enum clock_event_mode mode, 891 struct clock_event_device *dev) 892 { 893 if (mode != CLOCK_EVT_MODE_ONESHOT) 894 decrementer_set_next_event(DECREMENTER_MAX, dev); 895 } 896 897 static inline uint64_t div_sc64(unsigned long ticks, unsigned long nsec, 898 int shift) 899 { 900 uint64_t tmp = ((uint64_t)ticks) << shift; 901 902 do_div(tmp, nsec); 903 return tmp; 904 } 905 906 static void __init setup_clockevent_multiplier(unsigned long hz) 907 { 908 u64 mult, shift = 32; 909 910 while (1) { 911 mult = div_sc64(hz, NSEC_PER_SEC, shift); 912 if (mult && (mult >> 32UL) == 0UL) 913 break; 914 915 shift--; 916 } 917 918 decrementer_clockevent.shift = shift; 919 decrementer_clockevent.mult = mult; 920 } 921 922 static void register_decrementer_clockevent(int cpu) 923 { 924 struct clock_event_device *dec = &per_cpu(decrementers, cpu).event; 925 926 *dec = decrementer_clockevent; 927 dec->cpumask = cpumask_of(cpu); 928 929 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 930 dec->name, dec->mult, dec->shift, cpu); 931 932 clockevents_register_device(dec); 933 } 934 935 static void __init init_decrementer_clockevent(void) 936 { 937 int cpu = smp_processor_id(); 938 939 setup_clockevent_multiplier(ppc_tb_freq); 940 decrementer_clockevent.max_delta_ns = 941 clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent); 942 decrementer_clockevent.min_delta_ns = 943 clockevent_delta2ns(2, &decrementer_clockevent); 944 945 register_decrementer_clockevent(cpu); 946 } 947 948 void secondary_cpu_time_init(void) 949 { 950 /* Start the decrementer on CPUs that have manual control 951 * such as BookE 952 */ 953 start_cpu_decrementer(); 954 955 /* FIME: Should make unrelatred change to move snapshot_timebase 956 * call here ! */ 957 register_decrementer_clockevent(smp_processor_id()); 958 } 959 960 /* This function is only called on the boot processor */ 961 void __init time_init(void) 962 { 963 struct div_result res; 964 u64 scale; 965 unsigned shift; 966 967 if (__USE_RTC()) { 968 /* 601 processor: dec counts down by 128 every 128ns */ 969 ppc_tb_freq = 1000000000; 970 } else { 971 /* Normal PowerPC with timebase register */ 972 ppc_md.calibrate_decr(); 973 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 974 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 975 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 976 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 977 } 978 979 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 980 tb_ticks_per_sec = ppc_tb_freq; 981 tb_ticks_per_usec = ppc_tb_freq / 1000000; 982 calc_cputime_factors(); 983 setup_cputime_one_jiffy(); 984 985 /* 986 * Compute scale factor for sched_clock. 987 * The calibrate_decr() function has set tb_ticks_per_sec, 988 * which is the timebase frequency. 989 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 990 * the 128-bit result as a 64.64 fixed-point number. 991 * We then shift that number right until it is less than 1.0, 992 * giving us the scale factor and shift count to use in 993 * sched_clock(). 994 */ 995 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 996 scale = res.result_low; 997 for (shift = 0; res.result_high != 0; ++shift) { 998 scale = (scale >> 1) | (res.result_high << 63); 999 res.result_high >>= 1; 1000 } 1001 tb_to_ns_scale = scale; 1002 tb_to_ns_shift = shift; 1003 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 1004 boot_tb = get_tb_or_rtc(); 1005 1006 /* If platform provided a timezone (pmac), we correct the time */ 1007 if (timezone_offset) { 1008 sys_tz.tz_minuteswest = -timezone_offset / 60; 1009 sys_tz.tz_dsttime = 0; 1010 } 1011 1012 vdso_data->tb_update_count = 0; 1013 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 1014 1015 /* Start the decrementer on CPUs that have manual control 1016 * such as BookE 1017 */ 1018 start_cpu_decrementer(); 1019 1020 /* Register the clocksource, if we're not running on iSeries */ 1021 if (!firmware_has_feature(FW_FEATURE_ISERIES)) 1022 clocksource_init(); 1023 1024 init_decrementer_clockevent(); 1025 } 1026 1027 1028 #define FEBRUARY 2 1029 #define STARTOFTIME 1970 1030 #define SECDAY 86400L 1031 #define SECYR (SECDAY * 365) 1032 #define leapyear(year) ((year) % 4 == 0 && \ 1033 ((year) % 100 != 0 || (year) % 400 == 0)) 1034 #define days_in_year(a) (leapyear(a) ? 366 : 365) 1035 #define days_in_month(a) (month_days[(a) - 1]) 1036 1037 static int month_days[12] = { 1038 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 1039 }; 1040 1041 /* 1042 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) 1043 */ 1044 void GregorianDay(struct rtc_time * tm) 1045 { 1046 int leapsToDate; 1047 int lastYear; 1048 int day; 1049 int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; 1050 1051 lastYear = tm->tm_year - 1; 1052 1053 /* 1054 * Number of leap corrections to apply up to end of last year 1055 */ 1056 leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400; 1057 1058 /* 1059 * This year is a leap year if it is divisible by 4 except when it is 1060 * divisible by 100 unless it is divisible by 400 1061 * 1062 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was 1063 */ 1064 day = tm->tm_mon > 2 && leapyear(tm->tm_year); 1065 1066 day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + 1067 tm->tm_mday; 1068 1069 tm->tm_wday = day % 7; 1070 } 1071 1072 void to_tm(int tim, struct rtc_time * tm) 1073 { 1074 register int i; 1075 register long hms, day; 1076 1077 day = tim / SECDAY; 1078 hms = tim % SECDAY; 1079 1080 /* Hours, minutes, seconds are easy */ 1081 tm->tm_hour = hms / 3600; 1082 tm->tm_min = (hms % 3600) / 60; 1083 tm->tm_sec = (hms % 3600) % 60; 1084 1085 /* Number of years in days */ 1086 for (i = STARTOFTIME; day >= days_in_year(i); i++) 1087 day -= days_in_year(i); 1088 tm->tm_year = i; 1089 1090 /* Number of months in days left */ 1091 if (leapyear(tm->tm_year)) 1092 days_in_month(FEBRUARY) = 29; 1093 for (i = 1; day >= days_in_month(i); i++) 1094 day -= days_in_month(i); 1095 days_in_month(FEBRUARY) = 28; 1096 tm->tm_mon = i; 1097 1098 /* Days are what is left over (+1) from all that. */ 1099 tm->tm_mday = day + 1; 1100 1101 /* 1102 * Determine the day of week 1103 */ 1104 GregorianDay(tm); 1105 } 1106 1107 /* 1108 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 1109 * result. 1110 */ 1111 void div128_by_32(u64 dividend_high, u64 dividend_low, 1112 unsigned divisor, struct div_result *dr) 1113 { 1114 unsigned long a, b, c, d; 1115 unsigned long w, x, y, z; 1116 u64 ra, rb, rc; 1117 1118 a = dividend_high >> 32; 1119 b = dividend_high & 0xffffffff; 1120 c = dividend_low >> 32; 1121 d = dividend_low & 0xffffffff; 1122 1123 w = a / divisor; 1124 ra = ((u64)(a - (w * divisor)) << 32) + b; 1125 1126 rb = ((u64) do_div(ra, divisor) << 32) + c; 1127 x = ra; 1128 1129 rc = ((u64) do_div(rb, divisor) << 32) + d; 1130 y = rb; 1131 1132 do_div(rc, divisor); 1133 z = rc; 1134 1135 dr->result_high = ((u64)w << 32) + x; 1136 dr->result_low = ((u64)y << 32) + z; 1137 1138 } 1139 1140 /* We don't need to calibrate delay, we use the CPU timebase for that */ 1141 void calibrate_delay(void) 1142 { 1143 /* Some generic code (such as spinlock debug) use loops_per_jiffy 1144 * as the number of __delay(1) in a jiffy, so make it so 1145 */ 1146 loops_per_jiffy = tb_ticks_per_jiffy; 1147 } 1148 1149 static int __init rtc_init(void) 1150 { 1151 struct platform_device *pdev; 1152 1153 if (!ppc_md.get_rtc_time) 1154 return -ENODEV; 1155 1156 pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0); 1157 if (IS_ERR(pdev)) 1158 return PTR_ERR(pdev); 1159 1160 return 0; 1161 } 1162 1163 module_init(rtc_init); 1164