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 <linux/suspend.h> 59 #include <asm/trace.h> 60 61 #include <asm/io.h> 62 #include <asm/processor.h> 63 #include <asm/nvram.h> 64 #include <asm/cache.h> 65 #include <asm/machdep.h> 66 #include <asm/uaccess.h> 67 #include <asm/time.h> 68 #include <asm/prom.h> 69 #include <asm/irq.h> 70 #include <asm/div64.h> 71 #include <asm/smp.h> 72 #include <asm/vdso_datapage.h> 73 #include <asm/firmware.h> 74 #include <asm/cputime.h> 75 76 /* powerpc clocksource/clockevent code */ 77 78 #include <linux/clockchips.h> 79 #include <linux/timekeeper_internal.h> 80 81 static cycle_t rtc_read(struct clocksource *); 82 static struct clocksource clocksource_rtc = { 83 .name = "rtc", 84 .rating = 400, 85 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 86 .mask = CLOCKSOURCE_MASK(64), 87 .read = rtc_read, 88 }; 89 90 static cycle_t timebase_read(struct clocksource *); 91 static struct clocksource clocksource_timebase = { 92 .name = "timebase", 93 .rating = 400, 94 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 95 .mask = CLOCKSOURCE_MASK(64), 96 .read = timebase_read, 97 }; 98 99 #define DECREMENTER_DEFAULT_MAX 0x7FFFFFFF 100 u64 decrementer_max = DECREMENTER_DEFAULT_MAX; 101 102 static int decrementer_set_next_event(unsigned long evt, 103 struct clock_event_device *dev); 104 static int decrementer_shutdown(struct clock_event_device *evt); 105 106 struct clock_event_device decrementer_clockevent = { 107 .name = "decrementer", 108 .rating = 200, 109 .irq = 0, 110 .set_next_event = decrementer_set_next_event, 111 .set_state_shutdown = decrementer_shutdown, 112 .tick_resume = decrementer_shutdown, 113 .features = CLOCK_EVT_FEAT_ONESHOT | 114 CLOCK_EVT_FEAT_C3STOP, 115 }; 116 EXPORT_SYMBOL(decrementer_clockevent); 117 118 DEFINE_PER_CPU(u64, decrementers_next_tb); 119 static DEFINE_PER_CPU(struct clock_event_device, decrementers); 120 121 #define XSEC_PER_SEC (1024*1024) 122 123 #ifdef CONFIG_PPC64 124 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) 125 #else 126 /* compute ((xsec << 12) * max) >> 32 */ 127 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) 128 #endif 129 130 unsigned long tb_ticks_per_jiffy; 131 unsigned long tb_ticks_per_usec = 100; /* sane default */ 132 EXPORT_SYMBOL(tb_ticks_per_usec); 133 unsigned long tb_ticks_per_sec; 134 EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ 135 136 DEFINE_SPINLOCK(rtc_lock); 137 EXPORT_SYMBOL_GPL(rtc_lock); 138 139 static u64 tb_to_ns_scale __read_mostly; 140 static unsigned tb_to_ns_shift __read_mostly; 141 static u64 boot_tb __read_mostly; 142 143 extern struct timezone sys_tz; 144 static long timezone_offset; 145 146 unsigned long ppc_proc_freq; 147 EXPORT_SYMBOL_GPL(ppc_proc_freq); 148 unsigned long ppc_tb_freq; 149 EXPORT_SYMBOL_GPL(ppc_tb_freq); 150 151 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE 152 /* 153 * Factors for converting from cputime_t (timebase ticks) to 154 * jiffies, microseconds, seconds, and clock_t (1/USER_HZ seconds). 155 * These are all stored as 0.64 fixed-point binary fractions. 156 */ 157 u64 __cputime_jiffies_factor; 158 EXPORT_SYMBOL(__cputime_jiffies_factor); 159 u64 __cputime_usec_factor; 160 EXPORT_SYMBOL(__cputime_usec_factor); 161 u64 __cputime_sec_factor; 162 EXPORT_SYMBOL(__cputime_sec_factor); 163 u64 __cputime_clockt_factor; 164 EXPORT_SYMBOL(__cputime_clockt_factor); 165 DEFINE_PER_CPU(unsigned long, cputime_last_delta); 166 DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta); 167 168 cputime_t cputime_one_jiffy; 169 170 void (*dtl_consumer)(struct dtl_entry *, u64); 171 172 static void calc_cputime_factors(void) 173 { 174 struct div_result res; 175 176 div128_by_32(HZ, 0, tb_ticks_per_sec, &res); 177 __cputime_jiffies_factor = res.result_low; 178 div128_by_32(1000000, 0, tb_ticks_per_sec, &res); 179 __cputime_usec_factor = res.result_low; 180 div128_by_32(1, 0, tb_ticks_per_sec, &res); 181 __cputime_sec_factor = res.result_low; 182 div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res); 183 __cputime_clockt_factor = res.result_low; 184 } 185 186 /* 187 * Read the SPURR on systems that have it, otherwise the PURR, 188 * or if that doesn't exist return the timebase value passed in. 189 */ 190 static u64 read_spurr(u64 tb) 191 { 192 if (cpu_has_feature(CPU_FTR_SPURR)) 193 return mfspr(SPRN_SPURR); 194 if (cpu_has_feature(CPU_FTR_PURR)) 195 return mfspr(SPRN_PURR); 196 return tb; 197 } 198 199 #ifdef CONFIG_PPC_SPLPAR 200 201 /* 202 * Scan the dispatch trace log and count up the stolen time. 203 * Should be called with interrupts disabled. 204 */ 205 static u64 scan_dispatch_log(u64 stop_tb) 206 { 207 u64 i = local_paca->dtl_ridx; 208 struct dtl_entry *dtl = local_paca->dtl_curr; 209 struct dtl_entry *dtl_end = local_paca->dispatch_log_end; 210 struct lppaca *vpa = local_paca->lppaca_ptr; 211 u64 tb_delta; 212 u64 stolen = 0; 213 u64 dtb; 214 215 if (!dtl) 216 return 0; 217 218 if (i == be64_to_cpu(vpa->dtl_idx)) 219 return 0; 220 while (i < be64_to_cpu(vpa->dtl_idx)) { 221 dtb = be64_to_cpu(dtl->timebase); 222 tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) + 223 be32_to_cpu(dtl->ready_to_enqueue_time); 224 barrier(); 225 if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) { 226 /* buffer has overflowed */ 227 i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG; 228 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG); 229 continue; 230 } 231 if (dtb > stop_tb) 232 break; 233 if (dtl_consumer) 234 dtl_consumer(dtl, i); 235 stolen += tb_delta; 236 ++i; 237 ++dtl; 238 if (dtl == dtl_end) 239 dtl = local_paca->dispatch_log; 240 } 241 local_paca->dtl_ridx = i; 242 local_paca->dtl_curr = dtl; 243 return stolen; 244 } 245 246 /* 247 * Accumulate stolen time by scanning the dispatch trace log. 248 * Called on entry from user mode. 249 */ 250 void accumulate_stolen_time(void) 251 { 252 u64 sst, ust; 253 254 u8 save_soft_enabled = local_paca->soft_enabled; 255 256 /* We are called early in the exception entry, before 257 * soft/hard_enabled are sync'ed to the expected state 258 * for the exception. We are hard disabled but the PACA 259 * needs to reflect that so various debug stuff doesn't 260 * complain 261 */ 262 local_paca->soft_enabled = 0; 263 264 sst = scan_dispatch_log(local_paca->starttime_user); 265 ust = scan_dispatch_log(local_paca->starttime); 266 local_paca->system_time -= sst; 267 local_paca->user_time -= ust; 268 local_paca->stolen_time += ust + sst; 269 270 local_paca->soft_enabled = save_soft_enabled; 271 } 272 273 static inline u64 calculate_stolen_time(u64 stop_tb) 274 { 275 u64 stolen = 0; 276 277 if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx)) { 278 stolen = scan_dispatch_log(stop_tb); 279 get_paca()->system_time -= stolen; 280 } 281 282 stolen += get_paca()->stolen_time; 283 get_paca()->stolen_time = 0; 284 return stolen; 285 } 286 287 #else /* CONFIG_PPC_SPLPAR */ 288 static inline u64 calculate_stolen_time(u64 stop_tb) 289 { 290 return 0; 291 } 292 293 #endif /* CONFIG_PPC_SPLPAR */ 294 295 /* 296 * Account time for a transition between system, hard irq 297 * or soft irq state. 298 */ 299 static u64 vtime_delta(struct task_struct *tsk, 300 u64 *sys_scaled, u64 *stolen) 301 { 302 u64 now, nowscaled, deltascaled; 303 u64 udelta, delta, user_scaled; 304 305 WARN_ON_ONCE(!irqs_disabled()); 306 307 now = mftb(); 308 nowscaled = read_spurr(now); 309 get_paca()->system_time += now - get_paca()->starttime; 310 get_paca()->starttime = now; 311 deltascaled = nowscaled - get_paca()->startspurr; 312 get_paca()->startspurr = nowscaled; 313 314 *stolen = calculate_stolen_time(now); 315 316 delta = get_paca()->system_time; 317 get_paca()->system_time = 0; 318 udelta = get_paca()->user_time - get_paca()->utime_sspurr; 319 get_paca()->utime_sspurr = get_paca()->user_time; 320 321 /* 322 * Because we don't read the SPURR on every kernel entry/exit, 323 * deltascaled includes both user and system SPURR ticks. 324 * Apportion these ticks to system SPURR ticks and user 325 * SPURR ticks in the same ratio as the system time (delta) 326 * and user time (udelta) values obtained from the timebase 327 * over the same interval. The system ticks get accounted here; 328 * the user ticks get saved up in paca->user_time_scaled to be 329 * used by account_process_tick. 330 */ 331 *sys_scaled = delta; 332 user_scaled = udelta; 333 if (deltascaled != delta + udelta) { 334 if (udelta) { 335 *sys_scaled = deltascaled * delta / (delta + udelta); 336 user_scaled = deltascaled - *sys_scaled; 337 } else { 338 *sys_scaled = deltascaled; 339 } 340 } 341 get_paca()->user_time_scaled += user_scaled; 342 343 return delta; 344 } 345 346 void vtime_account_system(struct task_struct *tsk) 347 { 348 u64 delta, sys_scaled, stolen; 349 350 delta = vtime_delta(tsk, &sys_scaled, &stolen); 351 account_system_time(tsk, 0, delta, sys_scaled); 352 if (stolen) 353 account_steal_time(stolen); 354 } 355 EXPORT_SYMBOL_GPL(vtime_account_system); 356 357 void vtime_account_idle(struct task_struct *tsk) 358 { 359 u64 delta, sys_scaled, stolen; 360 361 delta = vtime_delta(tsk, &sys_scaled, &stolen); 362 account_idle_time(delta + stolen); 363 } 364 365 /* 366 * Transfer the user time accumulated in the paca 367 * by the exception entry and exit code to the generic 368 * process user time records. 369 * Must be called with interrupts disabled. 370 * Assumes that vtime_account_system/idle() has been called 371 * recently (i.e. since the last entry from usermode) so that 372 * get_paca()->user_time_scaled is up to date. 373 */ 374 void vtime_account_user(struct task_struct *tsk) 375 { 376 cputime_t utime, utimescaled; 377 378 utime = get_paca()->user_time; 379 utimescaled = get_paca()->user_time_scaled; 380 get_paca()->user_time = 0; 381 get_paca()->user_time_scaled = 0; 382 get_paca()->utime_sspurr = 0; 383 account_user_time(tsk, utime, utimescaled); 384 } 385 386 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ 387 #define calc_cputime_factors() 388 #endif 389 390 void __delay(unsigned long loops) 391 { 392 unsigned long start; 393 int diff; 394 395 if (__USE_RTC()) { 396 start = get_rtcl(); 397 do { 398 /* the RTCL register wraps at 1000000000 */ 399 diff = get_rtcl() - start; 400 if (diff < 0) 401 diff += 1000000000; 402 } while (diff < loops); 403 } else { 404 start = get_tbl(); 405 while (get_tbl() - start < loops) 406 HMT_low(); 407 HMT_medium(); 408 } 409 } 410 EXPORT_SYMBOL(__delay); 411 412 void udelay(unsigned long usecs) 413 { 414 __delay(tb_ticks_per_usec * usecs); 415 } 416 EXPORT_SYMBOL(udelay); 417 418 #ifdef CONFIG_SMP 419 unsigned long profile_pc(struct pt_regs *regs) 420 { 421 unsigned long pc = instruction_pointer(regs); 422 423 if (in_lock_functions(pc)) 424 return regs->link; 425 426 return pc; 427 } 428 EXPORT_SYMBOL(profile_pc); 429 #endif 430 431 #ifdef CONFIG_IRQ_WORK 432 433 /* 434 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable... 435 */ 436 #ifdef CONFIG_PPC64 437 static inline unsigned long test_irq_work_pending(void) 438 { 439 unsigned long x; 440 441 asm volatile("lbz %0,%1(13)" 442 : "=r" (x) 443 : "i" (offsetof(struct paca_struct, irq_work_pending))); 444 return x; 445 } 446 447 static inline void set_irq_work_pending_flag(void) 448 { 449 asm volatile("stb %0,%1(13)" : : 450 "r" (1), 451 "i" (offsetof(struct paca_struct, irq_work_pending))); 452 } 453 454 static inline void clear_irq_work_pending(void) 455 { 456 asm volatile("stb %0,%1(13)" : : 457 "r" (0), 458 "i" (offsetof(struct paca_struct, irq_work_pending))); 459 } 460 461 #else /* 32-bit */ 462 463 DEFINE_PER_CPU(u8, irq_work_pending); 464 465 #define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1) 466 #define test_irq_work_pending() __this_cpu_read(irq_work_pending) 467 #define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0) 468 469 #endif /* 32 vs 64 bit */ 470 471 void arch_irq_work_raise(void) 472 { 473 preempt_disable(); 474 set_irq_work_pending_flag(); 475 set_dec(1); 476 preempt_enable(); 477 } 478 479 #else /* CONFIG_IRQ_WORK */ 480 481 #define test_irq_work_pending() 0 482 #define clear_irq_work_pending() 483 484 #endif /* CONFIG_IRQ_WORK */ 485 486 static void __timer_interrupt(void) 487 { 488 struct pt_regs *regs = get_irq_regs(); 489 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 490 struct clock_event_device *evt = this_cpu_ptr(&decrementers); 491 u64 now; 492 493 trace_timer_interrupt_entry(regs); 494 495 if (test_irq_work_pending()) { 496 clear_irq_work_pending(); 497 irq_work_run(); 498 } 499 500 now = get_tb_or_rtc(); 501 if (now >= *next_tb) { 502 *next_tb = ~(u64)0; 503 if (evt->event_handler) 504 evt->event_handler(evt); 505 __this_cpu_inc(irq_stat.timer_irqs_event); 506 } else { 507 now = *next_tb - now; 508 if (now <= decrementer_max) 509 set_dec(now); 510 /* We may have raced with new irq work */ 511 if (test_irq_work_pending()) 512 set_dec(1); 513 __this_cpu_inc(irq_stat.timer_irqs_others); 514 } 515 516 #ifdef CONFIG_PPC64 517 /* collect purr register values often, for accurate calculations */ 518 if (firmware_has_feature(FW_FEATURE_SPLPAR)) { 519 struct cpu_usage *cu = this_cpu_ptr(&cpu_usage_array); 520 cu->current_tb = mfspr(SPRN_PURR); 521 } 522 #endif 523 524 trace_timer_interrupt_exit(regs); 525 } 526 527 /* 528 * timer_interrupt - gets called when the decrementer overflows, 529 * with interrupts disabled. 530 */ 531 void timer_interrupt(struct pt_regs * regs) 532 { 533 struct pt_regs *old_regs; 534 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 535 536 /* Ensure a positive value is written to the decrementer, or else 537 * some CPUs will continue to take decrementer exceptions. 538 */ 539 set_dec(decrementer_max); 540 541 /* Some implementations of hotplug will get timer interrupts while 542 * offline, just ignore these and we also need to set 543 * decrementers_next_tb as MAX to make sure __check_irq_replay 544 * don't replay timer interrupt when return, otherwise we'll trap 545 * here infinitely :( 546 */ 547 if (!cpu_online(smp_processor_id())) { 548 *next_tb = ~(u64)0; 549 return; 550 } 551 552 /* Conditionally hard-enable interrupts now that the DEC has been 553 * bumped to its maximum value 554 */ 555 may_hard_irq_enable(); 556 557 558 #if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC) 559 if (atomic_read(&ppc_n_lost_interrupts) != 0) 560 do_IRQ(regs); 561 #endif 562 563 old_regs = set_irq_regs(regs); 564 irq_enter(); 565 566 __timer_interrupt(); 567 irq_exit(); 568 set_irq_regs(old_regs); 569 } 570 571 /* 572 * Hypervisor decrementer interrupts shouldn't occur but are sometimes 573 * left pending on exit from a KVM guest. We don't need to do anything 574 * to clear them, as they are edge-triggered. 575 */ 576 void hdec_interrupt(struct pt_regs *regs) 577 { 578 } 579 580 #ifdef CONFIG_SUSPEND 581 static void generic_suspend_disable_irqs(void) 582 { 583 /* Disable the decrementer, so that it doesn't interfere 584 * with suspending. 585 */ 586 587 set_dec(decrementer_max); 588 local_irq_disable(); 589 set_dec(decrementer_max); 590 } 591 592 static void generic_suspend_enable_irqs(void) 593 { 594 local_irq_enable(); 595 } 596 597 /* Overrides the weak version in kernel/power/main.c */ 598 void arch_suspend_disable_irqs(void) 599 { 600 if (ppc_md.suspend_disable_irqs) 601 ppc_md.suspend_disable_irqs(); 602 generic_suspend_disable_irqs(); 603 } 604 605 /* Overrides the weak version in kernel/power/main.c */ 606 void arch_suspend_enable_irqs(void) 607 { 608 generic_suspend_enable_irqs(); 609 if (ppc_md.suspend_enable_irqs) 610 ppc_md.suspend_enable_irqs(); 611 } 612 #endif 613 614 unsigned long long tb_to_ns(unsigned long long ticks) 615 { 616 return mulhdu(ticks, tb_to_ns_scale) << tb_to_ns_shift; 617 } 618 EXPORT_SYMBOL_GPL(tb_to_ns); 619 620 /* 621 * Scheduler clock - returns current time in nanosec units. 622 * 623 * Note: mulhdu(a, b) (multiply high double unsigned) returns 624 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 625 * are 64-bit unsigned numbers. 626 */ 627 unsigned long long sched_clock(void) 628 { 629 if (__USE_RTC()) 630 return get_rtc(); 631 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 632 } 633 634 635 #ifdef CONFIG_PPC_PSERIES 636 637 /* 638 * Running clock - attempts to give a view of time passing for a virtualised 639 * kernels. 640 * Uses the VTB register if available otherwise a next best guess. 641 */ 642 unsigned long long running_clock(void) 643 { 644 /* 645 * Don't read the VTB as a host since KVM does not switch in host 646 * timebase into the VTB when it takes a guest off the CPU, reading the 647 * VTB would result in reading 'last switched out' guest VTB. 648 * 649 * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it 650 * would be unsafe to rely only on the #ifdef above. 651 */ 652 if (firmware_has_feature(FW_FEATURE_LPAR) && 653 cpu_has_feature(CPU_FTR_ARCH_207S)) 654 return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 655 656 /* 657 * This is a next best approximation without a VTB. 658 * On a host which is running bare metal there should never be any stolen 659 * time and on a host which doesn't do any virtualisation TB *should* equal 660 * VTB so it makes no difference anyway. 661 */ 662 return local_clock() - cputime_to_nsecs(kcpustat_this_cpu->cpustat[CPUTIME_STEAL]); 663 } 664 #endif 665 666 static int __init get_freq(char *name, int cells, unsigned long *val) 667 { 668 struct device_node *cpu; 669 const __be32 *fp; 670 int found = 0; 671 672 /* The cpu node should have timebase and clock frequency properties */ 673 cpu = of_find_node_by_type(NULL, "cpu"); 674 675 if (cpu) { 676 fp = of_get_property(cpu, name, NULL); 677 if (fp) { 678 found = 1; 679 *val = of_read_ulong(fp, cells); 680 } 681 682 of_node_put(cpu); 683 } 684 685 return found; 686 } 687 688 static void start_cpu_decrementer(void) 689 { 690 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) 691 /* Clear any pending timer interrupts */ 692 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 693 694 /* Enable decrementer interrupt */ 695 mtspr(SPRN_TCR, TCR_DIE); 696 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */ 697 } 698 699 void __init generic_calibrate_decr(void) 700 { 701 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 702 703 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 704 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 705 706 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 707 "(not found)\n"); 708 } 709 710 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 711 712 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 713 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 714 715 printk(KERN_ERR "WARNING: Estimating processor frequency " 716 "(not found)\n"); 717 } 718 } 719 720 int update_persistent_clock(struct timespec now) 721 { 722 struct rtc_time tm; 723 724 if (!ppc_md.set_rtc_time) 725 return -ENODEV; 726 727 to_tm(now.tv_sec + 1 + timezone_offset, &tm); 728 tm.tm_year -= 1900; 729 tm.tm_mon -= 1; 730 731 return ppc_md.set_rtc_time(&tm); 732 } 733 734 static void __read_persistent_clock(struct timespec *ts) 735 { 736 struct rtc_time tm; 737 static int first = 1; 738 739 ts->tv_nsec = 0; 740 /* XXX this is a litle fragile but will work okay in the short term */ 741 if (first) { 742 first = 0; 743 if (ppc_md.time_init) 744 timezone_offset = ppc_md.time_init(); 745 746 /* get_boot_time() isn't guaranteed to be safe to call late */ 747 if (ppc_md.get_boot_time) { 748 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 749 return; 750 } 751 } 752 if (!ppc_md.get_rtc_time) { 753 ts->tv_sec = 0; 754 return; 755 } 756 ppc_md.get_rtc_time(&tm); 757 758 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, 759 tm.tm_hour, tm.tm_min, tm.tm_sec); 760 } 761 762 void read_persistent_clock(struct timespec *ts) 763 { 764 __read_persistent_clock(ts); 765 766 /* Sanitize it in case real time clock is set below EPOCH */ 767 if (ts->tv_sec < 0) { 768 ts->tv_sec = 0; 769 ts->tv_nsec = 0; 770 } 771 772 } 773 774 /* clocksource code */ 775 static cycle_t rtc_read(struct clocksource *cs) 776 { 777 return (cycle_t)get_rtc(); 778 } 779 780 static cycle_t timebase_read(struct clocksource *cs) 781 { 782 return (cycle_t)get_tb(); 783 } 784 785 void update_vsyscall_old(struct timespec *wall_time, struct timespec *wtm, 786 struct clocksource *clock, u32 mult, cycle_t cycle_last) 787 { 788 u64 new_tb_to_xs, new_stamp_xsec; 789 u32 frac_sec; 790 791 if (clock != &clocksource_timebase) 792 return; 793 794 /* Make userspace gettimeofday spin until we're done. */ 795 ++vdso_data->tb_update_count; 796 smp_mb(); 797 798 /* 19342813113834067 ~= 2^(20+64) / 1e9 */ 799 new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift); 800 new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC; 801 do_div(new_stamp_xsec, 1000000000); 802 new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC; 803 804 BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC); 805 /* this is tv_nsec / 1e9 as a 0.32 fraction */ 806 frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32; 807 808 /* 809 * tb_update_count is used to allow the userspace gettimeofday code 810 * to assure itself that it sees a consistent view of the tb_to_xs and 811 * stamp_xsec variables. It reads the tb_update_count, then reads 812 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If 813 * the two values of tb_update_count match and are even then the 814 * tb_to_xs and stamp_xsec values are consistent. If not, then it 815 * loops back and reads them again until this criteria is met. 816 * We expect the caller to have done the first increment of 817 * vdso_data->tb_update_count already. 818 */ 819 vdso_data->tb_orig_stamp = cycle_last; 820 vdso_data->stamp_xsec = new_stamp_xsec; 821 vdso_data->tb_to_xs = new_tb_to_xs; 822 vdso_data->wtom_clock_sec = wtm->tv_sec; 823 vdso_data->wtom_clock_nsec = wtm->tv_nsec; 824 vdso_data->stamp_xtime = *wall_time; 825 vdso_data->stamp_sec_fraction = frac_sec; 826 smp_wmb(); 827 ++(vdso_data->tb_update_count); 828 } 829 830 void update_vsyscall_tz(void) 831 { 832 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; 833 vdso_data->tz_dsttime = sys_tz.tz_dsttime; 834 } 835 836 static void __init clocksource_init(void) 837 { 838 struct clocksource *clock; 839 840 if (__USE_RTC()) 841 clock = &clocksource_rtc; 842 else 843 clock = &clocksource_timebase; 844 845 if (clocksource_register_hz(clock, tb_ticks_per_sec)) { 846 printk(KERN_ERR "clocksource: %s is already registered\n", 847 clock->name); 848 return; 849 } 850 851 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 852 clock->name, clock->mult, clock->shift); 853 } 854 855 static int decrementer_set_next_event(unsigned long evt, 856 struct clock_event_device *dev) 857 { 858 __this_cpu_write(decrementers_next_tb, get_tb_or_rtc() + evt); 859 set_dec(evt); 860 861 /* We may have raced with new irq work */ 862 if (test_irq_work_pending()) 863 set_dec(1); 864 865 return 0; 866 } 867 868 static int decrementer_shutdown(struct clock_event_device *dev) 869 { 870 decrementer_set_next_event(decrementer_max, dev); 871 return 0; 872 } 873 874 /* Interrupt handler for the timer broadcast IPI */ 875 void tick_broadcast_ipi_handler(void) 876 { 877 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 878 879 *next_tb = get_tb_or_rtc(); 880 __timer_interrupt(); 881 } 882 883 static void register_decrementer_clockevent(int cpu) 884 { 885 struct clock_event_device *dec = &per_cpu(decrementers, cpu); 886 887 *dec = decrementer_clockevent; 888 dec->cpumask = cpumask_of(cpu); 889 890 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 891 dec->name, dec->mult, dec->shift, cpu); 892 893 clockevents_register_device(dec); 894 } 895 896 static void enable_large_decrementer(void) 897 { 898 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 899 return; 900 901 if (decrementer_max <= DECREMENTER_DEFAULT_MAX) 902 return; 903 904 /* 905 * If we're running as the hypervisor we need to enable the LD manually 906 * otherwise firmware should have done it for us. 907 */ 908 if (cpu_has_feature(CPU_FTR_HVMODE)) 909 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_LD); 910 } 911 912 static void __init set_decrementer_max(void) 913 { 914 struct device_node *cpu; 915 u32 bits = 32; 916 917 /* Prior to ISAv3 the decrementer is always 32 bit */ 918 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 919 return; 920 921 cpu = of_find_node_by_type(NULL, "cpu"); 922 923 if (of_property_read_u32(cpu, "ibm,dec-bits", &bits) == 0) { 924 if (bits > 64 || bits < 32) { 925 pr_warn("time_init: firmware supplied invalid ibm,dec-bits"); 926 bits = 32; 927 } 928 929 /* calculate the signed maximum given this many bits */ 930 decrementer_max = (1ul << (bits - 1)) - 1; 931 } 932 933 of_node_put(cpu); 934 935 pr_info("time_init: %u bit decrementer (max: %llx)\n", 936 bits, decrementer_max); 937 } 938 939 static void __init init_decrementer_clockevent(void) 940 { 941 int cpu = smp_processor_id(); 942 943 clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4); 944 945 decrementer_clockevent.max_delta_ns = 946 clockevent_delta2ns(decrementer_max, &decrementer_clockevent); 947 decrementer_clockevent.min_delta_ns = 948 clockevent_delta2ns(2, &decrementer_clockevent); 949 950 register_decrementer_clockevent(cpu); 951 } 952 953 void secondary_cpu_time_init(void) 954 { 955 /* Enable and test the large decrementer for this cpu */ 956 enable_large_decrementer(); 957 958 /* Start the decrementer on CPUs that have manual control 959 * such as BookE 960 */ 961 start_cpu_decrementer(); 962 963 /* FIME: Should make unrelatred change to move snapshot_timebase 964 * call here ! */ 965 register_decrementer_clockevent(smp_processor_id()); 966 } 967 968 /* This function is only called on the boot processor */ 969 void __init time_init(void) 970 { 971 struct div_result res; 972 u64 scale; 973 unsigned shift; 974 975 if (__USE_RTC()) { 976 /* 601 processor: dec counts down by 128 every 128ns */ 977 ppc_tb_freq = 1000000000; 978 } else { 979 /* Normal PowerPC with timebase register */ 980 ppc_md.calibrate_decr(); 981 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 982 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 983 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 984 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 985 } 986 987 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 988 tb_ticks_per_sec = ppc_tb_freq; 989 tb_ticks_per_usec = ppc_tb_freq / 1000000; 990 calc_cputime_factors(); 991 setup_cputime_one_jiffy(); 992 993 /* 994 * Compute scale factor for sched_clock. 995 * The calibrate_decr() function has set tb_ticks_per_sec, 996 * which is the timebase frequency. 997 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 998 * the 128-bit result as a 64.64 fixed-point number. 999 * We then shift that number right until it is less than 1.0, 1000 * giving us the scale factor and shift count to use in 1001 * sched_clock(). 1002 */ 1003 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 1004 scale = res.result_low; 1005 for (shift = 0; res.result_high != 0; ++shift) { 1006 scale = (scale >> 1) | (res.result_high << 63); 1007 res.result_high >>= 1; 1008 } 1009 tb_to_ns_scale = scale; 1010 tb_to_ns_shift = shift; 1011 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 1012 boot_tb = get_tb_or_rtc(); 1013 1014 /* If platform provided a timezone (pmac), we correct the time */ 1015 if (timezone_offset) { 1016 sys_tz.tz_minuteswest = -timezone_offset / 60; 1017 sys_tz.tz_dsttime = 0; 1018 } 1019 1020 vdso_data->tb_update_count = 0; 1021 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 1022 1023 /* initialise and enable the large decrementer (if we have one) */ 1024 set_decrementer_max(); 1025 enable_large_decrementer(); 1026 1027 /* Start the decrementer on CPUs that have manual control 1028 * such as BookE 1029 */ 1030 start_cpu_decrementer(); 1031 1032 /* Register the clocksource */ 1033 clocksource_init(); 1034 1035 init_decrementer_clockevent(); 1036 tick_setup_hrtimer_broadcast(); 1037 1038 #ifdef CONFIG_COMMON_CLK 1039 of_clk_init(NULL); 1040 #endif 1041 } 1042 1043 1044 #define FEBRUARY 2 1045 #define STARTOFTIME 1970 1046 #define SECDAY 86400L 1047 #define SECYR (SECDAY * 365) 1048 #define leapyear(year) ((year) % 4 == 0 && \ 1049 ((year) % 100 != 0 || (year) % 400 == 0)) 1050 #define days_in_year(a) (leapyear(a) ? 366 : 365) 1051 #define days_in_month(a) (month_days[(a) - 1]) 1052 1053 static int month_days[12] = { 1054 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 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 * No-one uses the day of the week. 1088 */ 1089 tm->tm_wday = -1; 1090 } 1091 EXPORT_SYMBOL(to_tm); 1092 1093 /* 1094 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 1095 * result. 1096 */ 1097 void div128_by_32(u64 dividend_high, u64 dividend_low, 1098 unsigned divisor, struct div_result *dr) 1099 { 1100 unsigned long a, b, c, d; 1101 unsigned long w, x, y, z; 1102 u64 ra, rb, rc; 1103 1104 a = dividend_high >> 32; 1105 b = dividend_high & 0xffffffff; 1106 c = dividend_low >> 32; 1107 d = dividend_low & 0xffffffff; 1108 1109 w = a / divisor; 1110 ra = ((u64)(a - (w * divisor)) << 32) + b; 1111 1112 rb = ((u64) do_div(ra, divisor) << 32) + c; 1113 x = ra; 1114 1115 rc = ((u64) do_div(rb, divisor) << 32) + d; 1116 y = rb; 1117 1118 do_div(rc, divisor); 1119 z = rc; 1120 1121 dr->result_high = ((u64)w << 32) + x; 1122 dr->result_low = ((u64)y << 32) + z; 1123 1124 } 1125 1126 /* We don't need to calibrate delay, we use the CPU timebase for that */ 1127 void calibrate_delay(void) 1128 { 1129 /* Some generic code (such as spinlock debug) use loops_per_jiffy 1130 * as the number of __delay(1) in a jiffy, so make it so 1131 */ 1132 loops_per_jiffy = tb_ticks_per_jiffy; 1133 } 1134 1135 static int __init rtc_init(void) 1136 { 1137 struct platform_device *pdev; 1138 1139 if (!ppc_md.get_rtc_time) 1140 return -ENODEV; 1141 1142 pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0); 1143 1144 return PTR_ERR_OR_ZERO(pdev); 1145 } 1146 1147 device_initcall(rtc_init); 1148