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