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 <linux/clk-provider.h> 58 #include <asm/trace.h> 59 60 #include <asm/io.h> 61 #include <asm/processor.h> 62 #include <asm/nvram.h> 63 #include <asm/cache.h> 64 #include <asm/machdep.h> 65 #include <asm/uaccess.h> 66 #include <asm/time.h> 67 #include <asm/prom.h> 68 #include <asm/irq.h> 69 #include <asm/div64.h> 70 #include <asm/smp.h> 71 #include <asm/vdso_datapage.h> 72 #include <asm/firmware.h> 73 #include <asm/cputime.h> 74 75 /* powerpc clocksource/clockevent code */ 76 77 #include <linux/clockchips.h> 78 #include <linux/timekeeper_internal.h> 79 80 static cycle_t rtc_read(struct clocksource *); 81 static struct clocksource clocksource_rtc = { 82 .name = "rtc", 83 .rating = 400, 84 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 85 .mask = CLOCKSOURCE_MASK(64), 86 .read = rtc_read, 87 }; 88 89 static cycle_t timebase_read(struct clocksource *); 90 static struct clocksource clocksource_timebase = { 91 .name = "timebase", 92 .rating = 400, 93 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 94 .mask = CLOCKSOURCE_MASK(64), 95 .read = timebase_read, 96 }; 97 98 #define DECREMENTER_MAX 0x7fffffff 99 100 static int decrementer_set_next_event(unsigned long evt, 101 struct clock_event_device *dev); 102 static void decrementer_set_mode(enum clock_event_mode mode, 103 struct clock_event_device *dev); 104 105 struct clock_event_device decrementer_clockevent = { 106 .name = "decrementer", 107 .rating = 200, 108 .irq = 0, 109 .set_next_event = decrementer_set_next_event, 110 .set_mode = decrementer_set_mode, 111 .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP, 112 }; 113 EXPORT_SYMBOL(decrementer_clockevent); 114 115 DEFINE_PER_CPU(u64, decrementers_next_tb); 116 static DEFINE_PER_CPU(struct clock_event_device, decrementers); 117 118 #define XSEC_PER_SEC (1024*1024) 119 120 #ifdef CONFIG_PPC64 121 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) 122 #else 123 /* compute ((xsec << 12) * max) >> 32 */ 124 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) 125 #endif 126 127 unsigned long tb_ticks_per_jiffy; 128 unsigned long tb_ticks_per_usec = 100; /* sane default */ 129 EXPORT_SYMBOL(tb_ticks_per_usec); 130 unsigned long tb_ticks_per_sec; 131 EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ 132 133 DEFINE_SPINLOCK(rtc_lock); 134 EXPORT_SYMBOL_GPL(rtc_lock); 135 136 static u64 tb_to_ns_scale __read_mostly; 137 static unsigned tb_to_ns_shift __read_mostly; 138 static u64 boot_tb __read_mostly; 139 140 extern struct timezone sys_tz; 141 static long timezone_offset; 142 143 unsigned long ppc_proc_freq; 144 EXPORT_SYMBOL_GPL(ppc_proc_freq); 145 unsigned long ppc_tb_freq; 146 EXPORT_SYMBOL_GPL(ppc_tb_freq); 147 148 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE 149 /* 150 * Factors for converting from cputime_t (timebase ticks) to 151 * jiffies, microseconds, seconds, and clock_t (1/USER_HZ seconds). 152 * These are all stored as 0.64 fixed-point binary fractions. 153 */ 154 u64 __cputime_jiffies_factor; 155 EXPORT_SYMBOL(__cputime_jiffies_factor); 156 u64 __cputime_usec_factor; 157 EXPORT_SYMBOL(__cputime_usec_factor); 158 u64 __cputime_sec_factor; 159 EXPORT_SYMBOL(__cputime_sec_factor); 160 u64 __cputime_clockt_factor; 161 EXPORT_SYMBOL(__cputime_clockt_factor); 162 DEFINE_PER_CPU(unsigned long, cputime_last_delta); 163 DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta); 164 165 cputime_t cputime_one_jiffy; 166 167 void (*dtl_consumer)(struct dtl_entry *, u64); 168 169 static void calc_cputime_factors(void) 170 { 171 struct div_result res; 172 173 div128_by_32(HZ, 0, tb_ticks_per_sec, &res); 174 __cputime_jiffies_factor = res.result_low; 175 div128_by_32(1000000, 0, tb_ticks_per_sec, &res); 176 __cputime_usec_factor = res.result_low; 177 div128_by_32(1, 0, tb_ticks_per_sec, &res); 178 __cputime_sec_factor = res.result_low; 179 div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res); 180 __cputime_clockt_factor = res.result_low; 181 } 182 183 /* 184 * Read the SPURR on systems that have it, otherwise the PURR, 185 * or if that doesn't exist return the timebase value passed in. 186 */ 187 static u64 read_spurr(u64 tb) 188 { 189 if (cpu_has_feature(CPU_FTR_SPURR)) 190 return mfspr(SPRN_SPURR); 191 if (cpu_has_feature(CPU_FTR_PURR)) 192 return mfspr(SPRN_PURR); 193 return tb; 194 } 195 196 #ifdef CONFIG_PPC_SPLPAR 197 198 /* 199 * Scan the dispatch trace log and count up the stolen time. 200 * Should be called with interrupts disabled. 201 */ 202 static u64 scan_dispatch_log(u64 stop_tb) 203 { 204 u64 i = local_paca->dtl_ridx; 205 struct dtl_entry *dtl = local_paca->dtl_curr; 206 struct dtl_entry *dtl_end = local_paca->dispatch_log_end; 207 struct lppaca *vpa = local_paca->lppaca_ptr; 208 u64 tb_delta; 209 u64 stolen = 0; 210 u64 dtb; 211 212 if (!dtl) 213 return 0; 214 215 if (i == be64_to_cpu(vpa->dtl_idx)) 216 return 0; 217 while (i < be64_to_cpu(vpa->dtl_idx)) { 218 dtb = be64_to_cpu(dtl->timebase); 219 tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) + 220 be32_to_cpu(dtl->ready_to_enqueue_time); 221 barrier(); 222 if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) { 223 /* buffer has overflowed */ 224 i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG; 225 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG); 226 continue; 227 } 228 if (dtb > stop_tb) 229 break; 230 if (dtl_consumer) 231 dtl_consumer(dtl, i); 232 stolen += tb_delta; 233 ++i; 234 ++dtl; 235 if (dtl == dtl_end) 236 dtl = local_paca->dispatch_log; 237 } 238 local_paca->dtl_ridx = i; 239 local_paca->dtl_curr = dtl; 240 return stolen; 241 } 242 243 /* 244 * Accumulate stolen time by scanning the dispatch trace log. 245 * Called on entry from user mode. 246 */ 247 void accumulate_stolen_time(void) 248 { 249 u64 sst, ust; 250 251 u8 save_soft_enabled = local_paca->soft_enabled; 252 253 /* We are called early in the exception entry, before 254 * soft/hard_enabled are sync'ed to the expected state 255 * for the exception. We are hard disabled but the PACA 256 * needs to reflect that so various debug stuff doesn't 257 * complain 258 */ 259 local_paca->soft_enabled = 0; 260 261 sst = scan_dispatch_log(local_paca->starttime_user); 262 ust = scan_dispatch_log(local_paca->starttime); 263 local_paca->system_time -= sst; 264 local_paca->user_time -= ust; 265 local_paca->stolen_time += ust + sst; 266 267 local_paca->soft_enabled = save_soft_enabled; 268 } 269 270 static inline u64 calculate_stolen_time(u64 stop_tb) 271 { 272 u64 stolen = 0; 273 274 if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx)) { 275 stolen = scan_dispatch_log(stop_tb); 276 get_paca()->system_time -= stolen; 277 } 278 279 stolen += get_paca()->stolen_time; 280 get_paca()->stolen_time = 0; 281 return stolen; 282 } 283 284 #else /* CONFIG_PPC_SPLPAR */ 285 static inline u64 calculate_stolen_time(u64 stop_tb) 286 { 287 return 0; 288 } 289 290 #endif /* CONFIG_PPC_SPLPAR */ 291 292 /* 293 * Account time for a transition between system, hard irq 294 * or soft irq state. 295 */ 296 static u64 vtime_delta(struct task_struct *tsk, 297 u64 *sys_scaled, u64 *stolen) 298 { 299 u64 now, nowscaled, deltascaled; 300 u64 udelta, delta, user_scaled; 301 302 WARN_ON_ONCE(!irqs_disabled()); 303 304 now = mftb(); 305 nowscaled = read_spurr(now); 306 get_paca()->system_time += now - get_paca()->starttime; 307 get_paca()->starttime = now; 308 deltascaled = nowscaled - get_paca()->startspurr; 309 get_paca()->startspurr = nowscaled; 310 311 *stolen = calculate_stolen_time(now); 312 313 delta = get_paca()->system_time; 314 get_paca()->system_time = 0; 315 udelta = get_paca()->user_time - get_paca()->utime_sspurr; 316 get_paca()->utime_sspurr = get_paca()->user_time; 317 318 /* 319 * Because we don't read the SPURR on every kernel entry/exit, 320 * deltascaled includes both user and system SPURR ticks. 321 * Apportion these ticks to system SPURR ticks and user 322 * SPURR ticks in the same ratio as the system time (delta) 323 * and user time (udelta) values obtained from the timebase 324 * over the same interval. The system ticks get accounted here; 325 * the user ticks get saved up in paca->user_time_scaled to be 326 * used by account_process_tick. 327 */ 328 *sys_scaled = delta; 329 user_scaled = udelta; 330 if (deltascaled != delta + udelta) { 331 if (udelta) { 332 *sys_scaled = deltascaled * delta / (delta + udelta); 333 user_scaled = deltascaled - *sys_scaled; 334 } else { 335 *sys_scaled = deltascaled; 336 } 337 } 338 get_paca()->user_time_scaled += user_scaled; 339 340 return delta; 341 } 342 343 void vtime_account_system(struct task_struct *tsk) 344 { 345 u64 delta, sys_scaled, stolen; 346 347 delta = vtime_delta(tsk, &sys_scaled, &stolen); 348 account_system_time(tsk, 0, delta, sys_scaled); 349 if (stolen) 350 account_steal_time(stolen); 351 } 352 EXPORT_SYMBOL_GPL(vtime_account_system); 353 354 void vtime_account_idle(struct task_struct *tsk) 355 { 356 u64 delta, sys_scaled, stolen; 357 358 delta = vtime_delta(tsk, &sys_scaled, &stolen); 359 account_idle_time(delta + stolen); 360 } 361 362 /* 363 * Transfer the user time accumulated in the paca 364 * by the exception entry and exit code to the generic 365 * process user time records. 366 * Must be called with interrupts disabled. 367 * Assumes that vtime_account_system/idle() has been called 368 * recently (i.e. since the last entry from usermode) so that 369 * get_paca()->user_time_scaled is up to date. 370 */ 371 void vtime_account_user(struct task_struct *tsk) 372 { 373 cputime_t utime, utimescaled; 374 375 utime = get_paca()->user_time; 376 utimescaled = get_paca()->user_time_scaled; 377 get_paca()->user_time = 0; 378 get_paca()->user_time_scaled = 0; 379 get_paca()->utime_sspurr = 0; 380 account_user_time(tsk, utime, utimescaled); 381 } 382 383 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ 384 #define calc_cputime_factors() 385 #endif 386 387 void __delay(unsigned long loops) 388 { 389 unsigned long start; 390 int diff; 391 392 if (__USE_RTC()) { 393 start = get_rtcl(); 394 do { 395 /* the RTCL register wraps at 1000000000 */ 396 diff = get_rtcl() - start; 397 if (diff < 0) 398 diff += 1000000000; 399 } while (diff < loops); 400 } else { 401 start = get_tbl(); 402 while (get_tbl() - start < loops) 403 HMT_low(); 404 HMT_medium(); 405 } 406 } 407 EXPORT_SYMBOL(__delay); 408 409 void udelay(unsigned long usecs) 410 { 411 __delay(tb_ticks_per_usec * usecs); 412 } 413 EXPORT_SYMBOL(udelay); 414 415 #ifdef CONFIG_SMP 416 unsigned long profile_pc(struct pt_regs *regs) 417 { 418 unsigned long pc = instruction_pointer(regs); 419 420 if (in_lock_functions(pc)) 421 return regs->link; 422 423 return pc; 424 } 425 EXPORT_SYMBOL(profile_pc); 426 #endif 427 428 #ifdef CONFIG_IRQ_WORK 429 430 /* 431 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable... 432 */ 433 #ifdef CONFIG_PPC64 434 static inline unsigned long test_irq_work_pending(void) 435 { 436 unsigned long x; 437 438 asm volatile("lbz %0,%1(13)" 439 : "=r" (x) 440 : "i" (offsetof(struct paca_struct, irq_work_pending))); 441 return x; 442 } 443 444 static inline void set_irq_work_pending_flag(void) 445 { 446 asm volatile("stb %0,%1(13)" : : 447 "r" (1), 448 "i" (offsetof(struct paca_struct, irq_work_pending))); 449 } 450 451 static inline void clear_irq_work_pending(void) 452 { 453 asm volatile("stb %0,%1(13)" : : 454 "r" (0), 455 "i" (offsetof(struct paca_struct, irq_work_pending))); 456 } 457 458 #else /* 32-bit */ 459 460 DEFINE_PER_CPU(u8, irq_work_pending); 461 462 #define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1) 463 #define test_irq_work_pending() __this_cpu_read(irq_work_pending) 464 #define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0) 465 466 #endif /* 32 vs 64 bit */ 467 468 void arch_irq_work_raise(void) 469 { 470 preempt_disable(); 471 set_irq_work_pending_flag(); 472 set_dec(1); 473 preempt_enable(); 474 } 475 476 #else /* CONFIG_IRQ_WORK */ 477 478 #define test_irq_work_pending() 0 479 #define clear_irq_work_pending() 480 481 #endif /* CONFIG_IRQ_WORK */ 482 483 static void __timer_interrupt(void) 484 { 485 struct pt_regs *regs = get_irq_regs(); 486 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 487 struct clock_event_device *evt = this_cpu_ptr(&decrementers); 488 u64 now; 489 490 trace_timer_interrupt_entry(regs); 491 492 if (test_irq_work_pending()) { 493 clear_irq_work_pending(); 494 irq_work_run(); 495 } 496 497 now = get_tb_or_rtc(); 498 if (now >= *next_tb) { 499 *next_tb = ~(u64)0; 500 if (evt->event_handler) 501 evt->event_handler(evt); 502 __this_cpu_inc(irq_stat.timer_irqs_event); 503 } else { 504 now = *next_tb - now; 505 if (now <= DECREMENTER_MAX) 506 set_dec((int)now); 507 /* We may have raced with new irq work */ 508 if (test_irq_work_pending()) 509 set_dec(1); 510 __this_cpu_inc(irq_stat.timer_irqs_others); 511 } 512 513 #ifdef CONFIG_PPC64 514 /* collect purr register values often, for accurate calculations */ 515 if (firmware_has_feature(FW_FEATURE_SPLPAR)) { 516 struct cpu_usage *cu = this_cpu_ptr(&cpu_usage_array); 517 cu->current_tb = mfspr(SPRN_PURR); 518 } 519 #endif 520 521 trace_timer_interrupt_exit(regs); 522 } 523 524 /* 525 * timer_interrupt - gets called when the decrementer overflows, 526 * with interrupts disabled. 527 */ 528 void timer_interrupt(struct pt_regs * regs) 529 { 530 struct pt_regs *old_regs; 531 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 532 533 /* Ensure a positive value is written to the decrementer, or else 534 * some CPUs will continue to take decrementer exceptions. 535 */ 536 set_dec(DECREMENTER_MAX); 537 538 /* Some implementations of hotplug will get timer interrupts while 539 * offline, just ignore these and we also need to set 540 * decrementers_next_tb as MAX to make sure __check_irq_replay 541 * don't replay timer interrupt when return, otherwise we'll trap 542 * here infinitely :( 543 */ 544 if (!cpu_online(smp_processor_id())) { 545 *next_tb = ~(u64)0; 546 return; 547 } 548 549 /* Conditionally hard-enable interrupts now that the DEC has been 550 * bumped to its maximum value 551 */ 552 may_hard_irq_enable(); 553 554 555 #if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC) 556 if (atomic_read(&ppc_n_lost_interrupts) != 0) 557 do_IRQ(regs); 558 #endif 559 560 old_regs = set_irq_regs(regs); 561 irq_enter(); 562 563 __timer_interrupt(); 564 irq_exit(); 565 set_irq_regs(old_regs); 566 } 567 568 /* 569 * Hypervisor decrementer interrupts shouldn't occur but are sometimes 570 * left pending on exit from a KVM guest. We don't need to do anything 571 * to clear them, as they are edge-triggered. 572 */ 573 void hdec_interrupt(struct pt_regs *regs) 574 { 575 } 576 577 #ifdef CONFIG_SUSPEND 578 static void generic_suspend_disable_irqs(void) 579 { 580 /* Disable the decrementer, so that it doesn't interfere 581 * with suspending. 582 */ 583 584 set_dec(DECREMENTER_MAX); 585 local_irq_disable(); 586 set_dec(DECREMENTER_MAX); 587 } 588 589 static void generic_suspend_enable_irqs(void) 590 { 591 local_irq_enable(); 592 } 593 594 /* Overrides the weak version in kernel/power/main.c */ 595 void arch_suspend_disable_irqs(void) 596 { 597 if (ppc_md.suspend_disable_irqs) 598 ppc_md.suspend_disable_irqs(); 599 generic_suspend_disable_irqs(); 600 } 601 602 /* Overrides the weak version in kernel/power/main.c */ 603 void arch_suspend_enable_irqs(void) 604 { 605 generic_suspend_enable_irqs(); 606 if (ppc_md.suspend_enable_irqs) 607 ppc_md.suspend_enable_irqs(); 608 } 609 #endif 610 611 unsigned long long tb_to_ns(unsigned long long ticks) 612 { 613 return mulhdu(ticks, tb_to_ns_scale) << tb_to_ns_shift; 614 } 615 EXPORT_SYMBOL_GPL(tb_to_ns); 616 617 /* 618 * Scheduler clock - returns current time in nanosec units. 619 * 620 * Note: mulhdu(a, b) (multiply high double unsigned) returns 621 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 622 * are 64-bit unsigned numbers. 623 */ 624 unsigned long long sched_clock(void) 625 { 626 if (__USE_RTC()) 627 return get_rtc(); 628 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 629 } 630 631 632 #ifdef CONFIG_PPC_PSERIES 633 634 /* 635 * Running clock - attempts to give a view of time passing for a virtualised 636 * kernels. 637 * Uses the VTB register if available otherwise a next best guess. 638 */ 639 unsigned long long running_clock(void) 640 { 641 /* 642 * Don't read the VTB as a host since KVM does not switch in host 643 * timebase into the VTB when it takes a guest off the CPU, reading the 644 * VTB would result in reading 'last switched out' guest VTB. 645 * 646 * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it 647 * would be unsafe to rely only on the #ifdef above. 648 */ 649 if (firmware_has_feature(FW_FEATURE_LPAR) && 650 cpu_has_feature(CPU_FTR_ARCH_207S)) 651 return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 652 653 /* 654 * This is a next best approximation without a VTB. 655 * On a host which is running bare metal there should never be any stolen 656 * time and on a host which doesn't do any virtualisation TB *should* equal 657 * VTB so it makes no difference anyway. 658 */ 659 return local_clock() - cputime_to_nsecs(kcpustat_this_cpu->cpustat[CPUTIME_STEAL]); 660 } 661 #endif 662 663 static int __init get_freq(char *name, int cells, unsigned long *val) 664 { 665 struct device_node *cpu; 666 const __be32 *fp; 667 int found = 0; 668 669 /* The cpu node should have timebase and clock frequency properties */ 670 cpu = of_find_node_by_type(NULL, "cpu"); 671 672 if (cpu) { 673 fp = of_get_property(cpu, name, NULL); 674 if (fp) { 675 found = 1; 676 *val = of_read_ulong(fp, cells); 677 } 678 679 of_node_put(cpu); 680 } 681 682 return found; 683 } 684 685 static void start_cpu_decrementer(void) 686 { 687 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) 688 /* Clear any pending timer interrupts */ 689 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 690 691 /* Enable decrementer interrupt */ 692 mtspr(SPRN_TCR, TCR_DIE); 693 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */ 694 } 695 696 void __init generic_calibrate_decr(void) 697 { 698 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 699 700 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 701 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 702 703 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 704 "(not found)\n"); 705 } 706 707 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 708 709 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 710 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 711 712 printk(KERN_ERR "WARNING: Estimating processor frequency " 713 "(not found)\n"); 714 } 715 } 716 717 int update_persistent_clock(struct timespec now) 718 { 719 struct rtc_time tm; 720 721 if (!ppc_md.set_rtc_time) 722 return -ENODEV; 723 724 to_tm(now.tv_sec + 1 + timezone_offset, &tm); 725 tm.tm_year -= 1900; 726 tm.tm_mon -= 1; 727 728 return ppc_md.set_rtc_time(&tm); 729 } 730 731 static void __read_persistent_clock(struct timespec *ts) 732 { 733 struct rtc_time tm; 734 static int first = 1; 735 736 ts->tv_nsec = 0; 737 /* XXX this is a litle fragile but will work okay in the short term */ 738 if (first) { 739 first = 0; 740 if (ppc_md.time_init) 741 timezone_offset = ppc_md.time_init(); 742 743 /* get_boot_time() isn't guaranteed to be safe to call late */ 744 if (ppc_md.get_boot_time) { 745 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 746 return; 747 } 748 } 749 if (!ppc_md.get_rtc_time) { 750 ts->tv_sec = 0; 751 return; 752 } 753 ppc_md.get_rtc_time(&tm); 754 755 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, 756 tm.tm_hour, tm.tm_min, tm.tm_sec); 757 } 758 759 void read_persistent_clock(struct timespec *ts) 760 { 761 __read_persistent_clock(ts); 762 763 /* Sanitize it in case real time clock is set below EPOCH */ 764 if (ts->tv_sec < 0) { 765 ts->tv_sec = 0; 766 ts->tv_nsec = 0; 767 } 768 769 } 770 771 /* clocksource code */ 772 static cycle_t rtc_read(struct clocksource *cs) 773 { 774 return (cycle_t)get_rtc(); 775 } 776 777 static cycle_t timebase_read(struct clocksource *cs) 778 { 779 return (cycle_t)get_tb(); 780 } 781 782 void update_vsyscall_old(struct timespec *wall_time, struct timespec *wtm, 783 struct clocksource *clock, u32 mult, cycle_t cycle_last) 784 { 785 u64 new_tb_to_xs, new_stamp_xsec; 786 u32 frac_sec; 787 788 if (clock != &clocksource_timebase) 789 return; 790 791 /* Make userspace gettimeofday spin until we're done. */ 792 ++vdso_data->tb_update_count; 793 smp_mb(); 794 795 /* 19342813113834067 ~= 2^(20+64) / 1e9 */ 796 new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift); 797 new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC; 798 do_div(new_stamp_xsec, 1000000000); 799 new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC; 800 801 BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC); 802 /* this is tv_nsec / 1e9 as a 0.32 fraction */ 803 frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32; 804 805 /* 806 * tb_update_count is used to allow the userspace gettimeofday code 807 * to assure itself that it sees a consistent view of the tb_to_xs and 808 * stamp_xsec variables. It reads the tb_update_count, then reads 809 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If 810 * the two values of tb_update_count match and are even then the 811 * tb_to_xs and stamp_xsec values are consistent. If not, then it 812 * loops back and reads them again until this criteria is met. 813 * We expect the caller to have done the first increment of 814 * vdso_data->tb_update_count already. 815 */ 816 vdso_data->tb_orig_stamp = cycle_last; 817 vdso_data->stamp_xsec = new_stamp_xsec; 818 vdso_data->tb_to_xs = new_tb_to_xs; 819 vdso_data->wtom_clock_sec = wtm->tv_sec; 820 vdso_data->wtom_clock_nsec = wtm->tv_nsec; 821 vdso_data->stamp_xtime = *wall_time; 822 vdso_data->stamp_sec_fraction = frac_sec; 823 smp_wmb(); 824 ++(vdso_data->tb_update_count); 825 } 826 827 void update_vsyscall_tz(void) 828 { 829 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; 830 vdso_data->tz_dsttime = sys_tz.tz_dsttime; 831 } 832 833 static void __init clocksource_init(void) 834 { 835 struct clocksource *clock; 836 837 if (__USE_RTC()) 838 clock = &clocksource_rtc; 839 else 840 clock = &clocksource_timebase; 841 842 if (clocksource_register_hz(clock, tb_ticks_per_sec)) { 843 printk(KERN_ERR "clocksource: %s is already registered\n", 844 clock->name); 845 return; 846 } 847 848 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 849 clock->name, clock->mult, clock->shift); 850 } 851 852 static int decrementer_set_next_event(unsigned long evt, 853 struct clock_event_device *dev) 854 { 855 __this_cpu_write(decrementers_next_tb, get_tb_or_rtc() + evt); 856 set_dec(evt); 857 858 /* We may have raced with new irq work */ 859 if (test_irq_work_pending()) 860 set_dec(1); 861 862 return 0; 863 } 864 865 static void decrementer_set_mode(enum clock_event_mode mode, 866 struct clock_event_device *dev) 867 { 868 if (mode != CLOCK_EVT_MODE_ONESHOT) 869 decrementer_set_next_event(DECREMENTER_MAX, dev); 870 } 871 872 /* Interrupt handler for the timer broadcast IPI */ 873 void tick_broadcast_ipi_handler(void) 874 { 875 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 876 877 *next_tb = get_tb_or_rtc(); 878 __timer_interrupt(); 879 } 880 881 static void register_decrementer_clockevent(int cpu) 882 { 883 struct clock_event_device *dec = &per_cpu(decrementers, cpu); 884 885 *dec = decrementer_clockevent; 886 dec->cpumask = cpumask_of(cpu); 887 888 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 889 dec->name, dec->mult, dec->shift, cpu); 890 891 clockevents_register_device(dec); 892 } 893 894 static void __init init_decrementer_clockevent(void) 895 { 896 int cpu = smp_processor_id(); 897 898 clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4); 899 900 decrementer_clockevent.max_delta_ns = 901 clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent); 902 decrementer_clockevent.min_delta_ns = 903 clockevent_delta2ns(2, &decrementer_clockevent); 904 905 register_decrementer_clockevent(cpu); 906 } 907 908 void secondary_cpu_time_init(void) 909 { 910 /* Start the decrementer on CPUs that have manual control 911 * such as BookE 912 */ 913 start_cpu_decrementer(); 914 915 /* FIME: Should make unrelatred change to move snapshot_timebase 916 * call here ! */ 917 register_decrementer_clockevent(smp_processor_id()); 918 } 919 920 /* This function is only called on the boot processor */ 921 void __init time_init(void) 922 { 923 struct div_result res; 924 u64 scale; 925 unsigned shift; 926 927 if (__USE_RTC()) { 928 /* 601 processor: dec counts down by 128 every 128ns */ 929 ppc_tb_freq = 1000000000; 930 } else { 931 /* Normal PowerPC with timebase register */ 932 ppc_md.calibrate_decr(); 933 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 934 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 935 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 936 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 937 } 938 939 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 940 tb_ticks_per_sec = ppc_tb_freq; 941 tb_ticks_per_usec = ppc_tb_freq / 1000000; 942 calc_cputime_factors(); 943 setup_cputime_one_jiffy(); 944 945 /* 946 * Compute scale factor for sched_clock. 947 * The calibrate_decr() function has set tb_ticks_per_sec, 948 * which is the timebase frequency. 949 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 950 * the 128-bit result as a 64.64 fixed-point number. 951 * We then shift that number right until it is less than 1.0, 952 * giving us the scale factor and shift count to use in 953 * sched_clock(). 954 */ 955 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 956 scale = res.result_low; 957 for (shift = 0; res.result_high != 0; ++shift) { 958 scale = (scale >> 1) | (res.result_high << 63); 959 res.result_high >>= 1; 960 } 961 tb_to_ns_scale = scale; 962 tb_to_ns_shift = shift; 963 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 964 boot_tb = get_tb_or_rtc(); 965 966 /* If platform provided a timezone (pmac), we correct the time */ 967 if (timezone_offset) { 968 sys_tz.tz_minuteswest = -timezone_offset / 60; 969 sys_tz.tz_dsttime = 0; 970 } 971 972 vdso_data->tb_update_count = 0; 973 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 974 975 /* Start the decrementer on CPUs that have manual control 976 * such as BookE 977 */ 978 start_cpu_decrementer(); 979 980 /* Register the clocksource */ 981 clocksource_init(); 982 983 init_decrementer_clockevent(); 984 tick_setup_hrtimer_broadcast(); 985 986 #ifdef CONFIG_COMMON_CLK 987 of_clk_init(NULL); 988 #endif 989 } 990 991 992 #define FEBRUARY 2 993 #define STARTOFTIME 1970 994 #define SECDAY 86400L 995 #define SECYR (SECDAY * 365) 996 #define leapyear(year) ((year) % 4 == 0 && \ 997 ((year) % 100 != 0 || (year) % 400 == 0)) 998 #define days_in_year(a) (leapyear(a) ? 366 : 365) 999 #define days_in_month(a) (month_days[(a) - 1]) 1000 1001 static int month_days[12] = { 1002 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 1003 }; 1004 1005 /* 1006 * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) 1007 */ 1008 void GregorianDay(struct rtc_time * tm) 1009 { 1010 int leapsToDate; 1011 int lastYear; 1012 int day; 1013 int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; 1014 1015 lastYear = tm->tm_year - 1; 1016 1017 /* 1018 * Number of leap corrections to apply up to end of last year 1019 */ 1020 leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400; 1021 1022 /* 1023 * This year is a leap year if it is divisible by 4 except when it is 1024 * divisible by 100 unless it is divisible by 400 1025 * 1026 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was 1027 */ 1028 day = tm->tm_mon > 2 && leapyear(tm->tm_year); 1029 1030 day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + 1031 tm->tm_mday; 1032 1033 tm->tm_wday = day % 7; 1034 } 1035 EXPORT_SYMBOL_GPL(GregorianDay); 1036 1037 void to_tm(int tim, struct rtc_time * tm) 1038 { 1039 register int i; 1040 register long hms, day; 1041 1042 day = tim / SECDAY; 1043 hms = tim % SECDAY; 1044 1045 /* Hours, minutes, seconds are easy */ 1046 tm->tm_hour = hms / 3600; 1047 tm->tm_min = (hms % 3600) / 60; 1048 tm->tm_sec = (hms % 3600) % 60; 1049 1050 /* Number of years in days */ 1051 for (i = STARTOFTIME; day >= days_in_year(i); i++) 1052 day -= days_in_year(i); 1053 tm->tm_year = i; 1054 1055 /* Number of months in days left */ 1056 if (leapyear(tm->tm_year)) 1057 days_in_month(FEBRUARY) = 29; 1058 for (i = 1; day >= days_in_month(i); i++) 1059 day -= days_in_month(i); 1060 days_in_month(FEBRUARY) = 28; 1061 tm->tm_mon = i; 1062 1063 /* Days are what is left over (+1) from all that. */ 1064 tm->tm_mday = day + 1; 1065 1066 /* 1067 * Determine the day of week 1068 */ 1069 GregorianDay(tm); 1070 } 1071 EXPORT_SYMBOL(to_tm); 1072 1073 /* 1074 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 1075 * result. 1076 */ 1077 void div128_by_32(u64 dividend_high, u64 dividend_low, 1078 unsigned divisor, struct div_result *dr) 1079 { 1080 unsigned long a, b, c, d; 1081 unsigned long w, x, y, z; 1082 u64 ra, rb, rc; 1083 1084 a = dividend_high >> 32; 1085 b = dividend_high & 0xffffffff; 1086 c = dividend_low >> 32; 1087 d = dividend_low & 0xffffffff; 1088 1089 w = a / divisor; 1090 ra = ((u64)(a - (w * divisor)) << 32) + b; 1091 1092 rb = ((u64) do_div(ra, divisor) << 32) + c; 1093 x = ra; 1094 1095 rc = ((u64) do_div(rb, divisor) << 32) + d; 1096 y = rb; 1097 1098 do_div(rc, divisor); 1099 z = rc; 1100 1101 dr->result_high = ((u64)w << 32) + x; 1102 dr->result_low = ((u64)y << 32) + z; 1103 1104 } 1105 1106 /* We don't need to calibrate delay, we use the CPU timebase for that */ 1107 void calibrate_delay(void) 1108 { 1109 /* Some generic code (such as spinlock debug) use loops_per_jiffy 1110 * as the number of __delay(1) in a jiffy, so make it so 1111 */ 1112 loops_per_jiffy = tb_ticks_per_jiffy; 1113 } 1114 1115 static int __init rtc_init(void) 1116 { 1117 struct platform_device *pdev; 1118 1119 if (!ppc_md.get_rtc_time) 1120 return -ENODEV; 1121 1122 pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0); 1123 1124 return PTR_ERR_OR_ZERO(pdev); 1125 } 1126 1127 module_init(rtc_init); 1128