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. 21 * - for astronomical applications: add a new function to get 22 * non ambiguous timestamps even around leap seconds. This needs 23 * a new timestamp format and a good name. 24 * 25 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 26 * "A Kernel Model for Precision Timekeeping" by Dave Mills 27 * 28 * This program is free software; you can redistribute it and/or 29 * modify it under the terms of the GNU General Public License 30 * as published by the Free Software Foundation; either version 31 * 2 of the License, or (at your option) any later version. 32 */ 33 34 #include <linux/errno.h> 35 #include <linux/export.h> 36 #include <linux/sched.h> 37 #include <linux/kernel.h> 38 #include <linux/param.h> 39 #include <linux/string.h> 40 #include <linux/mm.h> 41 #include <linux/interrupt.h> 42 #include <linux/timex.h> 43 #include <linux/kernel_stat.h> 44 #include <linux/time.h> 45 #include <linux/clockchips.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 74 /* powerpc clocksource/clockevent code */ 75 76 #include <linux/clockchips.h> 77 #include <linux/timekeeper_internal.h> 78 79 static cycle_t rtc_read(struct clocksource *); 80 static struct clocksource clocksource_rtc = { 81 .name = "rtc", 82 .rating = 400, 83 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 84 .mask = CLOCKSOURCE_MASK(64), 85 .read = rtc_read, 86 }; 87 88 static cycle_t timebase_read(struct clocksource *); 89 static struct clocksource clocksource_timebase = { 90 .name = "timebase", 91 .rating = 400, 92 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 93 .mask = CLOCKSOURCE_MASK(64), 94 .read = timebase_read, 95 }; 96 97 #define DECREMENTER_MAX 0x7fffffff 98 99 static int decrementer_set_next_event(unsigned long evt, 100 struct clock_event_device *dev); 101 static void decrementer_set_mode(enum clock_event_mode mode, 102 struct clock_event_device *dev); 103 104 struct clock_event_device decrementer_clockevent = { 105 .name = "decrementer", 106 .rating = 200, 107 .irq = 0, 108 .set_next_event = decrementer_set_next_event, 109 .set_mode = decrementer_set_mode, 110 .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP, 111 }; 112 EXPORT_SYMBOL(decrementer_clockevent); 113 114 DEFINE_PER_CPU(u64, decrementers_next_tb); 115 static DEFINE_PER_CPU(struct clock_event_device, decrementers); 116 117 #define XSEC_PER_SEC (1024*1024) 118 119 #ifdef CONFIG_PPC64 120 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) 121 #else 122 /* compute ((xsec << 12) * max) >> 32 */ 123 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) 124 #endif 125 126 unsigned long tb_ticks_per_jiffy; 127 unsigned long tb_ticks_per_usec = 100; /* sane default */ 128 EXPORT_SYMBOL(tb_ticks_per_usec); 129 unsigned long tb_ticks_per_sec; 130 EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ 131 132 DEFINE_SPINLOCK(rtc_lock); 133 EXPORT_SYMBOL_GPL(rtc_lock); 134 135 static u64 tb_to_ns_scale __read_mostly; 136 static unsigned tb_to_ns_shift __read_mostly; 137 static u64 boot_tb __read_mostly; 138 139 extern struct timezone sys_tz; 140 static long timezone_offset; 141 142 unsigned long ppc_proc_freq; 143 EXPORT_SYMBOL_GPL(ppc_proc_freq); 144 unsigned long ppc_tb_freq; 145 EXPORT_SYMBOL_GPL(ppc_tb_freq); 146 147 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE 148 /* 149 * Factors for converting from cputime_t (timebase ticks) to 150 * jiffies, microseconds, seconds, and clock_t (1/USER_HZ seconds). 151 * These are all stored as 0.64 fixed-point binary fractions. 152 */ 153 u64 __cputime_jiffies_factor; 154 EXPORT_SYMBOL(__cputime_jiffies_factor); 155 u64 __cputime_usec_factor; 156 EXPORT_SYMBOL(__cputime_usec_factor); 157 u64 __cputime_sec_factor; 158 EXPORT_SYMBOL(__cputime_sec_factor); 159 u64 __cputime_clockt_factor; 160 EXPORT_SYMBOL(__cputime_clockt_factor); 161 DEFINE_PER_CPU(unsigned long, cputime_last_delta); 162 DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta); 163 164 cputime_t cputime_one_jiffy; 165 166 void (*dtl_consumer)(struct dtl_entry *, u64); 167 168 static void calc_cputime_factors(void) 169 { 170 struct div_result res; 171 172 div128_by_32(HZ, 0, tb_ticks_per_sec, &res); 173 __cputime_jiffies_factor = res.result_low; 174 div128_by_32(1000000, 0, tb_ticks_per_sec, &res); 175 __cputime_usec_factor = res.result_low; 176 div128_by_32(1, 0, tb_ticks_per_sec, &res); 177 __cputime_sec_factor = res.result_low; 178 div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res); 179 __cputime_clockt_factor = res.result_low; 180 } 181 182 /* 183 * Read the SPURR on systems that have it, otherwise the PURR, 184 * or if that doesn't exist return the timebase value passed in. 185 */ 186 static u64 read_spurr(u64 tb) 187 { 188 if (cpu_has_feature(CPU_FTR_SPURR)) 189 return mfspr(SPRN_SPURR); 190 if (cpu_has_feature(CPU_FTR_PURR)) 191 return mfspr(SPRN_PURR); 192 return tb; 193 } 194 195 #ifdef CONFIG_PPC_SPLPAR 196 197 /* 198 * Scan the dispatch trace log and count up the stolen time. 199 * Should be called with interrupts disabled. 200 */ 201 static u64 scan_dispatch_log(u64 stop_tb) 202 { 203 u64 i = local_paca->dtl_ridx; 204 struct dtl_entry *dtl = local_paca->dtl_curr; 205 struct dtl_entry *dtl_end = local_paca->dispatch_log_end; 206 struct lppaca *vpa = local_paca->lppaca_ptr; 207 u64 tb_delta; 208 u64 stolen = 0; 209 u64 dtb; 210 211 if (!dtl) 212 return 0; 213 214 if (i == be64_to_cpu(vpa->dtl_idx)) 215 return 0; 216 while (i < be64_to_cpu(vpa->dtl_idx)) { 217 dtb = be64_to_cpu(dtl->timebase); 218 tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) + 219 be32_to_cpu(dtl->ready_to_enqueue_time); 220 barrier(); 221 if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) { 222 /* buffer has overflowed */ 223 i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG; 224 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG); 225 continue; 226 } 227 if (dtb > stop_tb) 228 break; 229 if (dtl_consumer) 230 dtl_consumer(dtl, i); 231 stolen += tb_delta; 232 ++i; 233 ++dtl; 234 if (dtl == dtl_end) 235 dtl = local_paca->dispatch_log; 236 } 237 local_paca->dtl_ridx = i; 238 local_paca->dtl_curr = dtl; 239 return stolen; 240 } 241 242 /* 243 * Accumulate stolen time by scanning the dispatch trace log. 244 * Called on entry from user mode. 245 */ 246 void accumulate_stolen_time(void) 247 { 248 u64 sst, ust; 249 250 u8 save_soft_enabled = local_paca->soft_enabled; 251 252 /* We are called early in the exception entry, before 253 * soft/hard_enabled are sync'ed to the expected state 254 * for the exception. We are hard disabled but the PACA 255 * needs to reflect that so various debug stuff doesn't 256 * complain 257 */ 258 local_paca->soft_enabled = 0; 259 260 sst = scan_dispatch_log(local_paca->starttime_user); 261 ust = scan_dispatch_log(local_paca->starttime); 262 local_paca->system_time -= sst; 263 local_paca->user_time -= ust; 264 local_paca->stolen_time += ust + sst; 265 266 local_paca->soft_enabled = save_soft_enabled; 267 } 268 269 static inline u64 calculate_stolen_time(u64 stop_tb) 270 { 271 u64 stolen = 0; 272 273 if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx)) { 274 stolen = scan_dispatch_log(stop_tb); 275 get_paca()->system_time -= stolen; 276 } 277 278 stolen += get_paca()->stolen_time; 279 get_paca()->stolen_time = 0; 280 return stolen; 281 } 282 283 #else /* CONFIG_PPC_SPLPAR */ 284 static inline u64 calculate_stolen_time(u64 stop_tb) 285 { 286 return 0; 287 } 288 289 #endif /* CONFIG_PPC_SPLPAR */ 290 291 /* 292 * Account time for a transition between system, hard irq 293 * or soft irq state. 294 */ 295 static u64 vtime_delta(struct task_struct *tsk, 296 u64 *sys_scaled, u64 *stolen) 297 { 298 u64 now, nowscaled, deltascaled; 299 u64 udelta, delta, user_scaled; 300 301 WARN_ON_ONCE(!irqs_disabled()); 302 303 now = mftb(); 304 nowscaled = read_spurr(now); 305 get_paca()->system_time += now - get_paca()->starttime; 306 get_paca()->starttime = now; 307 deltascaled = nowscaled - get_paca()->startspurr; 308 get_paca()->startspurr = nowscaled; 309 310 *stolen = calculate_stolen_time(now); 311 312 delta = get_paca()->system_time; 313 get_paca()->system_time = 0; 314 udelta = get_paca()->user_time - get_paca()->utime_sspurr; 315 get_paca()->utime_sspurr = get_paca()->user_time; 316 317 /* 318 * Because we don't read the SPURR on every kernel entry/exit, 319 * deltascaled includes both user and system SPURR ticks. 320 * Apportion these ticks to system SPURR ticks and user 321 * SPURR ticks in the same ratio as the system time (delta) 322 * and user time (udelta) values obtained from the timebase 323 * over the same interval. The system ticks get accounted here; 324 * the user ticks get saved up in paca->user_time_scaled to be 325 * used by account_process_tick. 326 */ 327 *sys_scaled = delta; 328 user_scaled = udelta; 329 if (deltascaled != delta + udelta) { 330 if (udelta) { 331 *sys_scaled = deltascaled * delta / (delta + udelta); 332 user_scaled = deltascaled - *sys_scaled; 333 } else { 334 *sys_scaled = deltascaled; 335 } 336 } 337 get_paca()->user_time_scaled += user_scaled; 338 339 return delta; 340 } 341 342 void vtime_account_system(struct task_struct *tsk) 343 { 344 u64 delta, sys_scaled, stolen; 345 346 delta = vtime_delta(tsk, &sys_scaled, &stolen); 347 account_system_time(tsk, 0, delta, sys_scaled); 348 if (stolen) 349 account_steal_time(stolen); 350 } 351 EXPORT_SYMBOL_GPL(vtime_account_system); 352 353 void vtime_account_idle(struct task_struct *tsk) 354 { 355 u64 delta, sys_scaled, stolen; 356 357 delta = vtime_delta(tsk, &sys_scaled, &stolen); 358 account_idle_time(delta + stolen); 359 } 360 361 /* 362 * Transfer the user time accumulated in the paca 363 * by the exception entry and exit code to the generic 364 * process user time records. 365 * Must be called with interrupts disabled. 366 * Assumes that vtime_account_system/idle() has been called 367 * recently (i.e. since the last entry from usermode) so that 368 * get_paca()->user_time_scaled is up to date. 369 */ 370 void vtime_account_user(struct task_struct *tsk) 371 { 372 cputime_t utime, utimescaled; 373 374 utime = get_paca()->user_time; 375 utimescaled = get_paca()->user_time_scaled; 376 get_paca()->user_time = 0; 377 get_paca()->user_time_scaled = 0; 378 get_paca()->utime_sspurr = 0; 379 account_user_time(tsk, utime, utimescaled); 380 } 381 382 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ 383 #define calc_cputime_factors() 384 #endif 385 386 void __delay(unsigned long loops) 387 { 388 unsigned long start; 389 int diff; 390 391 if (__USE_RTC()) { 392 start = get_rtcl(); 393 do { 394 /* the RTCL register wraps at 1000000000 */ 395 diff = get_rtcl() - start; 396 if (diff < 0) 397 diff += 1000000000; 398 } while (diff < loops); 399 } else { 400 start = get_tbl(); 401 while (get_tbl() - start < loops) 402 HMT_low(); 403 HMT_medium(); 404 } 405 } 406 EXPORT_SYMBOL(__delay); 407 408 void udelay(unsigned long usecs) 409 { 410 __delay(tb_ticks_per_usec * usecs); 411 } 412 EXPORT_SYMBOL(udelay); 413 414 #ifdef CONFIG_SMP 415 unsigned long profile_pc(struct pt_regs *regs) 416 { 417 unsigned long pc = instruction_pointer(regs); 418 419 if (in_lock_functions(pc)) 420 return regs->link; 421 422 return pc; 423 } 424 EXPORT_SYMBOL(profile_pc); 425 #endif 426 427 #ifdef CONFIG_IRQ_WORK 428 429 /* 430 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable... 431 */ 432 #ifdef CONFIG_PPC64 433 static inline unsigned long test_irq_work_pending(void) 434 { 435 unsigned long x; 436 437 asm volatile("lbz %0,%1(13)" 438 : "=r" (x) 439 : "i" (offsetof(struct paca_struct, irq_work_pending))); 440 return x; 441 } 442 443 static inline void set_irq_work_pending_flag(void) 444 { 445 asm volatile("stb %0,%1(13)" : : 446 "r" (1), 447 "i" (offsetof(struct paca_struct, irq_work_pending))); 448 } 449 450 static inline void clear_irq_work_pending(void) 451 { 452 asm volatile("stb %0,%1(13)" : : 453 "r" (0), 454 "i" (offsetof(struct paca_struct, irq_work_pending))); 455 } 456 457 #else /* 32-bit */ 458 459 DEFINE_PER_CPU(u8, irq_work_pending); 460 461 #define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1) 462 #define test_irq_work_pending() __this_cpu_read(irq_work_pending) 463 #define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0) 464 465 #endif /* 32 vs 64 bit */ 466 467 void arch_irq_work_raise(void) 468 { 469 preempt_disable(); 470 set_irq_work_pending_flag(); 471 set_dec(1); 472 preempt_enable(); 473 } 474 475 #else /* CONFIG_IRQ_WORK */ 476 477 #define test_irq_work_pending() 0 478 #define clear_irq_work_pending() 479 480 #endif /* CONFIG_IRQ_WORK */ 481 482 static void __timer_interrupt(void) 483 { 484 struct pt_regs *regs = get_irq_regs(); 485 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 486 struct clock_event_device *evt = this_cpu_ptr(&decrementers); 487 u64 now; 488 489 trace_timer_interrupt_entry(regs); 490 491 if (test_irq_work_pending()) { 492 clear_irq_work_pending(); 493 irq_work_run(); 494 } 495 496 now = get_tb_or_rtc(); 497 if (now >= *next_tb) { 498 *next_tb = ~(u64)0; 499 if (evt->event_handler) 500 evt->event_handler(evt); 501 __this_cpu_inc(irq_stat.timer_irqs_event); 502 } else { 503 now = *next_tb - now; 504 if (now <= DECREMENTER_MAX) 505 set_dec((int)now); 506 /* We may have raced with new irq work */ 507 if (test_irq_work_pending()) 508 set_dec(1); 509 __this_cpu_inc(irq_stat.timer_irqs_others); 510 } 511 512 #ifdef CONFIG_PPC64 513 /* collect purr register values often, for accurate calculations */ 514 if (firmware_has_feature(FW_FEATURE_SPLPAR)) { 515 struct cpu_usage *cu = this_cpu_ptr(&cpu_usage_array); 516 cu->current_tb = mfspr(SPRN_PURR); 517 } 518 #endif 519 520 trace_timer_interrupt_exit(regs); 521 } 522 523 /* 524 * timer_interrupt - gets called when the decrementer overflows, 525 * with interrupts disabled. 526 */ 527 void timer_interrupt(struct pt_regs * regs) 528 { 529 struct pt_regs *old_regs; 530 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 531 532 /* Ensure a positive value is written to the decrementer, or else 533 * some CPUs will continue to take decrementer exceptions. 534 */ 535 set_dec(DECREMENTER_MAX); 536 537 /* Some implementations of hotplug will get timer interrupts while 538 * offline, just ignore these and we also need to set 539 * decrementers_next_tb as MAX to make sure __check_irq_replay 540 * don't replay timer interrupt when return, otherwise we'll trap 541 * here infinitely :( 542 */ 543 if (!cpu_online(smp_processor_id())) { 544 *next_tb = ~(u64)0; 545 return; 546 } 547 548 /* Conditionally hard-enable interrupts now that the DEC has been 549 * bumped to its maximum value 550 */ 551 may_hard_irq_enable(); 552 553 554 #if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC) 555 if (atomic_read(&ppc_n_lost_interrupts) != 0) 556 do_IRQ(regs); 557 #endif 558 559 old_regs = set_irq_regs(regs); 560 irq_enter(); 561 562 __timer_interrupt(); 563 irq_exit(); 564 set_irq_regs(old_regs); 565 } 566 567 /* 568 * Hypervisor decrementer interrupts shouldn't occur but are sometimes 569 * left pending on exit from a KVM guest. We don't need to do anything 570 * to clear them, as they are edge-triggered. 571 */ 572 void hdec_interrupt(struct pt_regs *regs) 573 { 574 } 575 576 #ifdef CONFIG_SUSPEND 577 static void generic_suspend_disable_irqs(void) 578 { 579 /* Disable the decrementer, so that it doesn't interfere 580 * with suspending. 581 */ 582 583 set_dec(DECREMENTER_MAX); 584 local_irq_disable(); 585 set_dec(DECREMENTER_MAX); 586 } 587 588 static void generic_suspend_enable_irqs(void) 589 { 590 local_irq_enable(); 591 } 592 593 /* Overrides the weak version in kernel/power/main.c */ 594 void arch_suspend_disable_irqs(void) 595 { 596 if (ppc_md.suspend_disable_irqs) 597 ppc_md.suspend_disable_irqs(); 598 generic_suspend_disable_irqs(); 599 } 600 601 /* Overrides the weak version in kernel/power/main.c */ 602 void arch_suspend_enable_irqs(void) 603 { 604 generic_suspend_enable_irqs(); 605 if (ppc_md.suspend_enable_irqs) 606 ppc_md.suspend_enable_irqs(); 607 } 608 #endif 609 610 /* 611 * Scheduler clock - returns current time in nanosec units. 612 * 613 * Note: mulhdu(a, b) (multiply high double unsigned) returns 614 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 615 * are 64-bit unsigned numbers. 616 */ 617 unsigned long long sched_clock(void) 618 { 619 if (__USE_RTC()) 620 return get_rtc(); 621 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 622 } 623 624 625 #ifdef CONFIG_PPC_PSERIES 626 627 /* 628 * Running clock - attempts to give a view of time passing for a virtualised 629 * kernels. 630 * Uses the VTB register if available otherwise a next best guess. 631 */ 632 unsigned long long running_clock(void) 633 { 634 /* 635 * Don't read the VTB as a host since KVM does not switch in host 636 * timebase into the VTB when it takes a guest off the CPU, reading the 637 * VTB would result in reading 'last switched out' guest VTB. 638 * 639 * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it 640 * would be unsafe to rely only on the #ifdef above. 641 */ 642 if (firmware_has_feature(FW_FEATURE_LPAR) && 643 cpu_has_feature(CPU_FTR_ARCH_207S)) 644 return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 645 646 /* 647 * This is a next best approximation without a VTB. 648 * On a host which is running bare metal there should never be any stolen 649 * time and on a host which doesn't do any virtualisation TB *should* equal 650 * VTB so it makes no difference anyway. 651 */ 652 return local_clock() - cputime_to_nsecs(kcpustat_this_cpu->cpustat[CPUTIME_STEAL]); 653 } 654 #endif 655 656 static int __init get_freq(char *name, int cells, unsigned long *val) 657 { 658 struct device_node *cpu; 659 const __be32 *fp; 660 int found = 0; 661 662 /* The cpu node should have timebase and clock frequency properties */ 663 cpu = of_find_node_by_type(NULL, "cpu"); 664 665 if (cpu) { 666 fp = of_get_property(cpu, name, NULL); 667 if (fp) { 668 found = 1; 669 *val = of_read_ulong(fp, cells); 670 } 671 672 of_node_put(cpu); 673 } 674 675 return found; 676 } 677 678 static void start_cpu_decrementer(void) 679 { 680 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) 681 /* Clear any pending timer interrupts */ 682 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 683 684 /* Enable decrementer interrupt */ 685 mtspr(SPRN_TCR, TCR_DIE); 686 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */ 687 } 688 689 void __init generic_calibrate_decr(void) 690 { 691 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 692 693 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 694 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 695 696 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 697 "(not found)\n"); 698 } 699 700 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 701 702 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 703 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 704 705 printk(KERN_ERR "WARNING: Estimating processor frequency " 706 "(not found)\n"); 707 } 708 } 709 710 int update_persistent_clock(struct timespec now) 711 { 712 struct rtc_time tm; 713 714 if (!ppc_md.set_rtc_time) 715 return -ENODEV; 716 717 to_tm(now.tv_sec + 1 + timezone_offset, &tm); 718 tm.tm_year -= 1900; 719 tm.tm_mon -= 1; 720 721 return ppc_md.set_rtc_time(&tm); 722 } 723 724 static void __read_persistent_clock(struct timespec *ts) 725 { 726 struct rtc_time tm; 727 static int first = 1; 728 729 ts->tv_nsec = 0; 730 /* XXX this is a litle fragile but will work okay in the short term */ 731 if (first) { 732 first = 0; 733 if (ppc_md.time_init) 734 timezone_offset = ppc_md.time_init(); 735 736 /* get_boot_time() isn't guaranteed to be safe to call late */ 737 if (ppc_md.get_boot_time) { 738 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 739 return; 740 } 741 } 742 if (!ppc_md.get_rtc_time) { 743 ts->tv_sec = 0; 744 return; 745 } 746 ppc_md.get_rtc_time(&tm); 747 748 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, 749 tm.tm_hour, tm.tm_min, tm.tm_sec); 750 } 751 752 void read_persistent_clock(struct timespec *ts) 753 { 754 __read_persistent_clock(ts); 755 756 /* Sanitize it in case real time clock is set below EPOCH */ 757 if (ts->tv_sec < 0) { 758 ts->tv_sec = 0; 759 ts->tv_nsec = 0; 760 } 761 762 } 763 764 /* clocksource code */ 765 static cycle_t rtc_read(struct clocksource *cs) 766 { 767 return (cycle_t)get_rtc(); 768 } 769 770 static cycle_t timebase_read(struct clocksource *cs) 771 { 772 return (cycle_t)get_tb(); 773 } 774 775 void update_vsyscall_old(struct timespec *wall_time, struct timespec *wtm, 776 struct clocksource *clock, u32 mult, cycle_t cycle_last) 777 { 778 u64 new_tb_to_xs, new_stamp_xsec; 779 u32 frac_sec; 780 781 if (clock != &clocksource_timebase) 782 return; 783 784 /* Make userspace gettimeofday spin until we're done. */ 785 ++vdso_data->tb_update_count; 786 smp_mb(); 787 788 /* 19342813113834067 ~= 2^(20+64) / 1e9 */ 789 new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift); 790 new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC; 791 do_div(new_stamp_xsec, 1000000000); 792 new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC; 793 794 BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC); 795 /* this is tv_nsec / 1e9 as a 0.32 fraction */ 796 frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32; 797 798 /* 799 * tb_update_count is used to allow the userspace gettimeofday code 800 * to assure itself that it sees a consistent view of the tb_to_xs and 801 * stamp_xsec variables. It reads the tb_update_count, then reads 802 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If 803 * the two values of tb_update_count match and are even then the 804 * tb_to_xs and stamp_xsec values are consistent. If not, then it 805 * loops back and reads them again until this criteria is met. 806 * We expect the caller to have done the first increment of 807 * vdso_data->tb_update_count already. 808 */ 809 vdso_data->tb_orig_stamp = cycle_last; 810 vdso_data->stamp_xsec = new_stamp_xsec; 811 vdso_data->tb_to_xs = new_tb_to_xs; 812 vdso_data->wtom_clock_sec = wtm->tv_sec; 813 vdso_data->wtom_clock_nsec = wtm->tv_nsec; 814 vdso_data->stamp_xtime = *wall_time; 815 vdso_data->stamp_sec_fraction = frac_sec; 816 smp_wmb(); 817 ++(vdso_data->tb_update_count); 818 } 819 820 void update_vsyscall_tz(void) 821 { 822 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; 823 vdso_data->tz_dsttime = sys_tz.tz_dsttime; 824 } 825 826 static void __init clocksource_init(void) 827 { 828 struct clocksource *clock; 829 830 if (__USE_RTC()) 831 clock = &clocksource_rtc; 832 else 833 clock = &clocksource_timebase; 834 835 if (clocksource_register_hz(clock, tb_ticks_per_sec)) { 836 printk(KERN_ERR "clocksource: %s is already registered\n", 837 clock->name); 838 return; 839 } 840 841 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 842 clock->name, clock->mult, clock->shift); 843 } 844 845 static int decrementer_set_next_event(unsigned long evt, 846 struct clock_event_device *dev) 847 { 848 __this_cpu_write(decrementers_next_tb, get_tb_or_rtc() + evt); 849 set_dec(evt); 850 851 /* We may have raced with new irq work */ 852 if (test_irq_work_pending()) 853 set_dec(1); 854 855 return 0; 856 } 857 858 static void decrementer_set_mode(enum clock_event_mode mode, 859 struct clock_event_device *dev) 860 { 861 if (mode != CLOCK_EVT_MODE_ONESHOT) 862 decrementer_set_next_event(DECREMENTER_MAX, dev); 863 } 864 865 /* Interrupt handler for the timer broadcast IPI */ 866 void tick_broadcast_ipi_handler(void) 867 { 868 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 869 870 *next_tb = get_tb_or_rtc(); 871 __timer_interrupt(); 872 } 873 874 static void register_decrementer_clockevent(int cpu) 875 { 876 struct clock_event_device *dec = &per_cpu(decrementers, cpu); 877 878 *dec = decrementer_clockevent; 879 dec->cpumask = cpumask_of(cpu); 880 881 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 882 dec->name, dec->mult, dec->shift, cpu); 883 884 clockevents_register_device(dec); 885 } 886 887 static void __init init_decrementer_clockevent(void) 888 { 889 int cpu = smp_processor_id(); 890 891 clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4); 892 893 decrementer_clockevent.max_delta_ns = 894 clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent); 895 decrementer_clockevent.min_delta_ns = 896 clockevent_delta2ns(2, &decrementer_clockevent); 897 898 register_decrementer_clockevent(cpu); 899 } 900 901 void secondary_cpu_time_init(void) 902 { 903 /* Start the decrementer on CPUs that have manual control 904 * such as BookE 905 */ 906 start_cpu_decrementer(); 907 908 /* FIME: Should make unrelatred change to move snapshot_timebase 909 * call here ! */ 910 register_decrementer_clockevent(smp_processor_id()); 911 } 912 913 /* This function is only called on the boot processor */ 914 void __init time_init(void) 915 { 916 struct div_result res; 917 u64 scale; 918 unsigned shift; 919 920 if (__USE_RTC()) { 921 /* 601 processor: dec counts down by 128 every 128ns */ 922 ppc_tb_freq = 1000000000; 923 } else { 924 /* Normal PowerPC with timebase register */ 925 ppc_md.calibrate_decr(); 926 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 927 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 928 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 929 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 930 } 931 932 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 933 tb_ticks_per_sec = ppc_tb_freq; 934 tb_ticks_per_usec = ppc_tb_freq / 1000000; 935 calc_cputime_factors(); 936 setup_cputime_one_jiffy(); 937 938 /* 939 * Compute scale factor for sched_clock. 940 * The calibrate_decr() function has set tb_ticks_per_sec, 941 * which is the timebase frequency. 942 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 943 * the 128-bit result as a 64.64 fixed-point number. 944 * We then shift that number right until it is less than 1.0, 945 * giving us the scale factor and shift count to use in 946 * sched_clock(). 947 */ 948 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 949 scale = res.result_low; 950 for (shift = 0; res.result_high != 0; ++shift) { 951 scale = (scale >> 1) | (res.result_high << 63); 952 res.result_high >>= 1; 953 } 954 tb_to_ns_scale = scale; 955 tb_to_ns_shift = shift; 956 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 957 boot_tb = get_tb_or_rtc(); 958 959 /* If platform provided a timezone (pmac), we correct the time */ 960 if (timezone_offset) { 961 sys_tz.tz_minuteswest = -timezone_offset / 60; 962 sys_tz.tz_dsttime = 0; 963 } 964 965 vdso_data->tb_update_count = 0; 966 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 967 968 /* Start the decrementer on CPUs that have manual control 969 * such as BookE 970 */ 971 start_cpu_decrementer(); 972 973 /* Register the clocksource */ 974 clocksource_init(); 975 976 init_decrementer_clockevent(); 977 tick_setup_hrtimer_broadcast(); 978 } 979 980 981 #define FEBRUARY 2 982 #define STARTOFTIME 1970 983 #define SECDAY 86400L 984 #define SECYR (SECDAY * 365) 985 #define leapyear(year) ((year) % 4 == 0 && \ 986 ((year) % 100 != 0 || (year) % 400 == 0)) 987 #define days_in_year(a) (leapyear(a) ? 366 : 365) 988 #define days_in_month(a) (month_days[(a) - 1]) 989 990 static int month_days[12] = { 991 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 992 }; 993 994 /* 995 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) 996 */ 997 void GregorianDay(struct rtc_time * tm) 998 { 999 int leapsToDate; 1000 int lastYear; 1001 int day; 1002 int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; 1003 1004 lastYear = tm->tm_year - 1; 1005 1006 /* 1007 * Number of leap corrections to apply up to end of last year 1008 */ 1009 leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400; 1010 1011 /* 1012 * This year is a leap year if it is divisible by 4 except when it is 1013 * divisible by 100 unless it is divisible by 400 1014 * 1015 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was 1016 */ 1017 day = tm->tm_mon > 2 && leapyear(tm->tm_year); 1018 1019 day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + 1020 tm->tm_mday; 1021 1022 tm->tm_wday = day % 7; 1023 } 1024 EXPORT_SYMBOL_GPL(GregorianDay); 1025 1026 void to_tm(int tim, struct rtc_time * tm) 1027 { 1028 register int i; 1029 register long hms, day; 1030 1031 day = tim / SECDAY; 1032 hms = tim % SECDAY; 1033 1034 /* Hours, minutes, seconds are easy */ 1035 tm->tm_hour = hms / 3600; 1036 tm->tm_min = (hms % 3600) / 60; 1037 tm->tm_sec = (hms % 3600) % 60; 1038 1039 /* Number of years in days */ 1040 for (i = STARTOFTIME; day >= days_in_year(i); i++) 1041 day -= days_in_year(i); 1042 tm->tm_year = i; 1043 1044 /* Number of months in days left */ 1045 if (leapyear(tm->tm_year)) 1046 days_in_month(FEBRUARY) = 29; 1047 for (i = 1; day >= days_in_month(i); i++) 1048 day -= days_in_month(i); 1049 days_in_month(FEBRUARY) = 28; 1050 tm->tm_mon = i; 1051 1052 /* Days are what is left over (+1) from all that. */ 1053 tm->tm_mday = day + 1; 1054 1055 /* 1056 * Determine the day of week 1057 */ 1058 GregorianDay(tm); 1059 } 1060 EXPORT_SYMBOL(to_tm); 1061 1062 /* 1063 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 1064 * result. 1065 */ 1066 void div128_by_32(u64 dividend_high, u64 dividend_low, 1067 unsigned divisor, struct div_result *dr) 1068 { 1069 unsigned long a, b, c, d; 1070 unsigned long w, x, y, z; 1071 u64 ra, rb, rc; 1072 1073 a = dividend_high >> 32; 1074 b = dividend_high & 0xffffffff; 1075 c = dividend_low >> 32; 1076 d = dividend_low & 0xffffffff; 1077 1078 w = a / divisor; 1079 ra = ((u64)(a - (w * divisor)) << 32) + b; 1080 1081 rb = ((u64) do_div(ra, divisor) << 32) + c; 1082 x = ra; 1083 1084 rc = ((u64) do_div(rb, divisor) << 32) + d; 1085 y = rb; 1086 1087 do_div(rc, divisor); 1088 z = rc; 1089 1090 dr->result_high = ((u64)w << 32) + x; 1091 dr->result_low = ((u64)y << 32) + z; 1092 1093 } 1094 1095 /* We don't need to calibrate delay, we use the CPU timebase for that */ 1096 void calibrate_delay(void) 1097 { 1098 /* Some generic code (such as spinlock debug) use loops_per_jiffy 1099 * as the number of __delay(1) in a jiffy, so make it so 1100 */ 1101 loops_per_jiffy = tb_ticks_per_jiffy; 1102 } 1103 1104 static int __init rtc_init(void) 1105 { 1106 struct platform_device *pdev; 1107 1108 if (!ppc_md.get_rtc_time) 1109 return -ENODEV; 1110 1111 pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0); 1112 1113 return PTR_ERR_OR_ZERO(pdev); 1114 } 1115 1116 module_init(rtc_init); 1117