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 <linux/rtc.h> 60 #include <asm/trace.h> 61 62 #include <asm/io.h> 63 #include <asm/processor.h> 64 #include <asm/nvram.h> 65 #include <asm/cache.h> 66 #include <asm/machdep.h> 67 #include <asm/uaccess.h> 68 #include <asm/time.h> 69 #include <asm/prom.h> 70 #include <asm/irq.h> 71 #include <asm/div64.h> 72 #include <asm/smp.h> 73 #include <asm/vdso_datapage.h> 74 #include <asm/firmware.h> 75 #include <asm/cputime.h> 76 #include <asm/asm-prototypes.h> 77 78 /* powerpc clocksource/clockevent code */ 79 80 #include <linux/clockchips.h> 81 #include <linux/timekeeper_internal.h> 82 83 static cycle_t rtc_read(struct clocksource *); 84 static struct clocksource clocksource_rtc = { 85 .name = "rtc", 86 .rating = 400, 87 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 88 .mask = CLOCKSOURCE_MASK(64), 89 .read = rtc_read, 90 }; 91 92 static cycle_t timebase_read(struct clocksource *); 93 static struct clocksource clocksource_timebase = { 94 .name = "timebase", 95 .rating = 400, 96 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 97 .mask = CLOCKSOURCE_MASK(64), 98 .read = timebase_read, 99 }; 100 101 #define DECREMENTER_DEFAULT_MAX 0x7FFFFFFF 102 u64 decrementer_max = DECREMENTER_DEFAULT_MAX; 103 104 static int decrementer_set_next_event(unsigned long evt, 105 struct clock_event_device *dev); 106 static int decrementer_shutdown(struct clock_event_device *evt); 107 108 struct clock_event_device decrementer_clockevent = { 109 .name = "decrementer", 110 .rating = 200, 111 .irq = 0, 112 .set_next_event = decrementer_set_next_event, 113 .set_state_shutdown = decrementer_shutdown, 114 .tick_resume = decrementer_shutdown, 115 .features = CLOCK_EVT_FEAT_ONESHOT | 116 CLOCK_EVT_FEAT_C3STOP, 117 }; 118 EXPORT_SYMBOL(decrementer_clockevent); 119 120 DEFINE_PER_CPU(u64, decrementers_next_tb); 121 static DEFINE_PER_CPU(struct clock_event_device, decrementers); 122 123 #define XSEC_PER_SEC (1024*1024) 124 125 #ifdef CONFIG_PPC64 126 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) 127 #else 128 /* compute ((xsec << 12) * max) >> 32 */ 129 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) 130 #endif 131 132 unsigned long tb_ticks_per_jiffy; 133 unsigned long tb_ticks_per_usec = 100; /* sane default */ 134 EXPORT_SYMBOL(tb_ticks_per_usec); 135 unsigned long tb_ticks_per_sec; 136 EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ 137 138 DEFINE_SPINLOCK(rtc_lock); 139 EXPORT_SYMBOL_GPL(rtc_lock); 140 141 static u64 tb_to_ns_scale __read_mostly; 142 static unsigned tb_to_ns_shift __read_mostly; 143 static u64 boot_tb __read_mostly; 144 145 extern struct timezone sys_tz; 146 static long timezone_offset; 147 148 unsigned long ppc_proc_freq; 149 EXPORT_SYMBOL_GPL(ppc_proc_freq); 150 unsigned long ppc_tb_freq; 151 EXPORT_SYMBOL_GPL(ppc_tb_freq); 152 153 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE 154 /* 155 * Factors for converting from cputime_t (timebase ticks) to 156 * jiffies, microseconds, seconds, and clock_t (1/USER_HZ seconds). 157 * These are all stored as 0.64 fixed-point binary fractions. 158 */ 159 u64 __cputime_jiffies_factor; 160 EXPORT_SYMBOL(__cputime_jiffies_factor); 161 u64 __cputime_usec_factor; 162 EXPORT_SYMBOL(__cputime_usec_factor); 163 u64 __cputime_sec_factor; 164 EXPORT_SYMBOL(__cputime_sec_factor); 165 u64 __cputime_clockt_factor; 166 EXPORT_SYMBOL(__cputime_clockt_factor); 167 DEFINE_PER_CPU(unsigned long, cputime_last_delta); 168 DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta); 169 170 cputime_t cputime_one_jiffy; 171 172 #ifdef CONFIG_PPC_SPLPAR 173 void (*dtl_consumer)(struct dtl_entry *, u64); 174 #endif 175 176 #ifdef CONFIG_PPC64 177 #define get_accounting(tsk) (&get_paca()->accounting) 178 #else 179 #define get_accounting(tsk) (&task_thread_info(tsk)->accounting) 180 #endif 181 182 static void calc_cputime_factors(void) 183 { 184 struct div_result res; 185 186 div128_by_32(HZ, 0, tb_ticks_per_sec, &res); 187 __cputime_jiffies_factor = res.result_low; 188 div128_by_32(1000000, 0, tb_ticks_per_sec, &res); 189 __cputime_usec_factor = res.result_low; 190 div128_by_32(1, 0, tb_ticks_per_sec, &res); 191 __cputime_sec_factor = res.result_low; 192 div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res); 193 __cputime_clockt_factor = res.result_low; 194 } 195 196 /* 197 * Read the SPURR on systems that have it, otherwise the PURR, 198 * or if that doesn't exist return the timebase value passed in. 199 */ 200 static unsigned long read_spurr(unsigned long tb) 201 { 202 if (cpu_has_feature(CPU_FTR_SPURR)) 203 return mfspr(SPRN_SPURR); 204 if (cpu_has_feature(CPU_FTR_PURR)) 205 return mfspr(SPRN_PURR); 206 return tb; 207 } 208 209 #ifdef CONFIG_PPC_SPLPAR 210 211 /* 212 * Scan the dispatch trace log and count up the stolen time. 213 * Should be called with interrupts disabled. 214 */ 215 static u64 scan_dispatch_log(u64 stop_tb) 216 { 217 u64 i = local_paca->dtl_ridx; 218 struct dtl_entry *dtl = local_paca->dtl_curr; 219 struct dtl_entry *dtl_end = local_paca->dispatch_log_end; 220 struct lppaca *vpa = local_paca->lppaca_ptr; 221 u64 tb_delta; 222 u64 stolen = 0; 223 u64 dtb; 224 225 if (!dtl) 226 return 0; 227 228 if (i == be64_to_cpu(vpa->dtl_idx)) 229 return 0; 230 while (i < be64_to_cpu(vpa->dtl_idx)) { 231 dtb = be64_to_cpu(dtl->timebase); 232 tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) + 233 be32_to_cpu(dtl->ready_to_enqueue_time); 234 barrier(); 235 if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) { 236 /* buffer has overflowed */ 237 i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG; 238 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG); 239 continue; 240 } 241 if (dtb > stop_tb) 242 break; 243 if (dtl_consumer) 244 dtl_consumer(dtl, i); 245 stolen += tb_delta; 246 ++i; 247 ++dtl; 248 if (dtl == dtl_end) 249 dtl = local_paca->dispatch_log; 250 } 251 local_paca->dtl_ridx = i; 252 local_paca->dtl_curr = dtl; 253 return stolen; 254 } 255 256 /* 257 * Accumulate stolen time by scanning the dispatch trace log. 258 * Called on entry from user mode. 259 */ 260 void accumulate_stolen_time(void) 261 { 262 u64 sst, ust; 263 u8 save_soft_enabled = local_paca->soft_enabled; 264 struct cpu_accounting_data *acct = &local_paca->accounting; 265 266 /* We are called early in the exception entry, before 267 * soft/hard_enabled are sync'ed to the expected state 268 * for the exception. We are hard disabled but the PACA 269 * needs to reflect that so various debug stuff doesn't 270 * complain 271 */ 272 local_paca->soft_enabled = 0; 273 274 sst = scan_dispatch_log(acct->starttime_user); 275 ust = scan_dispatch_log(acct->starttime); 276 acct->system_time -= sst; 277 acct->user_time -= ust; 278 local_paca->stolen_time += ust + sst; 279 280 local_paca->soft_enabled = save_soft_enabled; 281 } 282 283 static inline u64 calculate_stolen_time(u64 stop_tb) 284 { 285 u64 stolen = 0; 286 287 if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx)) { 288 stolen = scan_dispatch_log(stop_tb); 289 get_paca()->accounting.system_time -= stolen; 290 } 291 292 stolen += get_paca()->stolen_time; 293 get_paca()->stolen_time = 0; 294 return stolen; 295 } 296 297 #else /* CONFIG_PPC_SPLPAR */ 298 static inline u64 calculate_stolen_time(u64 stop_tb) 299 { 300 return 0; 301 } 302 303 #endif /* CONFIG_PPC_SPLPAR */ 304 305 /* 306 * Account time for a transition between system, hard irq 307 * or soft irq state. 308 */ 309 static unsigned long vtime_delta(struct task_struct *tsk, 310 unsigned long *sys_scaled, 311 unsigned long *stolen) 312 { 313 unsigned long now, nowscaled, deltascaled; 314 unsigned long udelta, delta, user_scaled; 315 struct cpu_accounting_data *acct = get_accounting(tsk); 316 317 WARN_ON_ONCE(!irqs_disabled()); 318 319 now = mftb(); 320 nowscaled = read_spurr(now); 321 acct->system_time += now - acct->starttime; 322 acct->starttime = now; 323 deltascaled = nowscaled - acct->startspurr; 324 acct->startspurr = nowscaled; 325 326 *stolen = calculate_stolen_time(now); 327 328 delta = acct->system_time; 329 acct->system_time = 0; 330 udelta = acct->user_time - acct->utime_sspurr; 331 acct->utime_sspurr = acct->user_time; 332 333 /* 334 * Because we don't read the SPURR on every kernel entry/exit, 335 * deltascaled includes both user and system SPURR ticks. 336 * Apportion these ticks to system SPURR ticks and user 337 * SPURR ticks in the same ratio as the system time (delta) 338 * and user time (udelta) values obtained from the timebase 339 * over the same interval. The system ticks get accounted here; 340 * the user ticks get saved up in paca->user_time_scaled to be 341 * used by account_process_tick. 342 */ 343 *sys_scaled = delta; 344 user_scaled = udelta; 345 if (deltascaled != delta + udelta) { 346 if (udelta) { 347 *sys_scaled = deltascaled * delta / (delta + udelta); 348 user_scaled = deltascaled - *sys_scaled; 349 } else { 350 *sys_scaled = deltascaled; 351 } 352 } 353 acct->user_time_scaled += user_scaled; 354 355 return delta; 356 } 357 358 void vtime_account_system(struct task_struct *tsk) 359 { 360 unsigned long delta, sys_scaled, stolen; 361 362 delta = vtime_delta(tsk, &sys_scaled, &stolen); 363 account_system_time(tsk, 0, delta, sys_scaled); 364 if (stolen) 365 account_steal_time(stolen); 366 } 367 EXPORT_SYMBOL_GPL(vtime_account_system); 368 369 void vtime_account_idle(struct task_struct *tsk) 370 { 371 unsigned long delta, sys_scaled, stolen; 372 373 delta = vtime_delta(tsk, &sys_scaled, &stolen); 374 account_idle_time(delta + stolen); 375 } 376 377 /* 378 * Transfer the user time accumulated in the paca 379 * by the exception entry and exit code to the generic 380 * process user time records. 381 * Must be called with interrupts disabled. 382 * Assumes that vtime_account_system/idle() has been called 383 * recently (i.e. since the last entry from usermode) so that 384 * get_paca()->user_time_scaled is up to date. 385 */ 386 void vtime_account_user(struct task_struct *tsk) 387 { 388 cputime_t utime, utimescaled; 389 struct cpu_accounting_data *acct = get_accounting(tsk); 390 391 utime = acct->user_time; 392 utimescaled = acct->user_time_scaled; 393 acct->user_time = 0; 394 acct->user_time_scaled = 0; 395 acct->utime_sspurr = 0; 396 account_user_time(tsk, utime, utimescaled); 397 } 398 399 #ifdef CONFIG_PPC32 400 /* 401 * Called from the context switch with interrupts disabled, to charge all 402 * accumulated times to the current process, and to prepare accounting on 403 * the next process. 404 */ 405 void arch_vtime_task_switch(struct task_struct *prev) 406 { 407 struct cpu_accounting_data *acct = get_accounting(current); 408 409 acct->starttime = get_accounting(prev)->starttime; 410 acct->system_time = 0; 411 acct->user_time = 0; 412 } 413 #endif /* CONFIG_PPC32 */ 414 415 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ 416 #define calc_cputime_factors() 417 #endif 418 419 void __delay(unsigned long loops) 420 { 421 unsigned long start; 422 int diff; 423 424 if (__USE_RTC()) { 425 start = get_rtcl(); 426 do { 427 /* the RTCL register wraps at 1000000000 */ 428 diff = get_rtcl() - start; 429 if (diff < 0) 430 diff += 1000000000; 431 } while (diff < loops); 432 } else { 433 start = get_tbl(); 434 while (get_tbl() - start < loops) 435 HMT_low(); 436 HMT_medium(); 437 } 438 } 439 EXPORT_SYMBOL(__delay); 440 441 void udelay(unsigned long usecs) 442 { 443 __delay(tb_ticks_per_usec * usecs); 444 } 445 EXPORT_SYMBOL(udelay); 446 447 #ifdef CONFIG_SMP 448 unsigned long profile_pc(struct pt_regs *regs) 449 { 450 unsigned long pc = instruction_pointer(regs); 451 452 if (in_lock_functions(pc)) 453 return regs->link; 454 455 return pc; 456 } 457 EXPORT_SYMBOL(profile_pc); 458 #endif 459 460 #ifdef CONFIG_IRQ_WORK 461 462 /* 463 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable... 464 */ 465 #ifdef CONFIG_PPC64 466 static inline unsigned long test_irq_work_pending(void) 467 { 468 unsigned long x; 469 470 asm volatile("lbz %0,%1(13)" 471 : "=r" (x) 472 : "i" (offsetof(struct paca_struct, irq_work_pending))); 473 return x; 474 } 475 476 static inline void set_irq_work_pending_flag(void) 477 { 478 asm volatile("stb %0,%1(13)" : : 479 "r" (1), 480 "i" (offsetof(struct paca_struct, irq_work_pending))); 481 } 482 483 static inline void clear_irq_work_pending(void) 484 { 485 asm volatile("stb %0,%1(13)" : : 486 "r" (0), 487 "i" (offsetof(struct paca_struct, irq_work_pending))); 488 } 489 490 #else /* 32-bit */ 491 492 DEFINE_PER_CPU(u8, irq_work_pending); 493 494 #define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1) 495 #define test_irq_work_pending() __this_cpu_read(irq_work_pending) 496 #define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0) 497 498 #endif /* 32 vs 64 bit */ 499 500 void arch_irq_work_raise(void) 501 { 502 preempt_disable(); 503 set_irq_work_pending_flag(); 504 set_dec(1); 505 preempt_enable(); 506 } 507 508 #else /* CONFIG_IRQ_WORK */ 509 510 #define test_irq_work_pending() 0 511 #define clear_irq_work_pending() 512 513 #endif /* CONFIG_IRQ_WORK */ 514 515 static void __timer_interrupt(void) 516 { 517 struct pt_regs *regs = get_irq_regs(); 518 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 519 struct clock_event_device *evt = this_cpu_ptr(&decrementers); 520 u64 now; 521 522 trace_timer_interrupt_entry(regs); 523 524 if (test_irq_work_pending()) { 525 clear_irq_work_pending(); 526 irq_work_run(); 527 } 528 529 now = get_tb_or_rtc(); 530 if (now >= *next_tb) { 531 *next_tb = ~(u64)0; 532 if (evt->event_handler) 533 evt->event_handler(evt); 534 __this_cpu_inc(irq_stat.timer_irqs_event); 535 } else { 536 now = *next_tb - now; 537 if (now <= decrementer_max) 538 set_dec(now); 539 /* We may have raced with new irq work */ 540 if (test_irq_work_pending()) 541 set_dec(1); 542 __this_cpu_inc(irq_stat.timer_irqs_others); 543 } 544 545 #ifdef CONFIG_PPC64 546 /* collect purr register values often, for accurate calculations */ 547 if (firmware_has_feature(FW_FEATURE_SPLPAR)) { 548 struct cpu_usage *cu = this_cpu_ptr(&cpu_usage_array); 549 cu->current_tb = mfspr(SPRN_PURR); 550 } 551 #endif 552 553 trace_timer_interrupt_exit(regs); 554 } 555 556 /* 557 * timer_interrupt - gets called when the decrementer overflows, 558 * with interrupts disabled. 559 */ 560 void timer_interrupt(struct pt_regs * regs) 561 { 562 struct pt_regs *old_regs; 563 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 564 565 /* Ensure a positive value is written to the decrementer, or else 566 * some CPUs will continue to take decrementer exceptions. 567 */ 568 set_dec(decrementer_max); 569 570 /* Some implementations of hotplug will get timer interrupts while 571 * offline, just ignore these and we also need to set 572 * decrementers_next_tb as MAX to make sure __check_irq_replay 573 * don't replay timer interrupt when return, otherwise we'll trap 574 * here infinitely :( 575 */ 576 if (!cpu_online(smp_processor_id())) { 577 *next_tb = ~(u64)0; 578 return; 579 } 580 581 /* Conditionally hard-enable interrupts now that the DEC has been 582 * bumped to its maximum value 583 */ 584 may_hard_irq_enable(); 585 586 587 #if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC) 588 if (atomic_read(&ppc_n_lost_interrupts) != 0) 589 do_IRQ(regs); 590 #endif 591 592 old_regs = set_irq_regs(regs); 593 irq_enter(); 594 595 __timer_interrupt(); 596 irq_exit(); 597 set_irq_regs(old_regs); 598 } 599 EXPORT_SYMBOL(timer_interrupt); 600 601 /* 602 * Hypervisor decrementer interrupts shouldn't occur but are sometimes 603 * left pending on exit from a KVM guest. We don't need to do anything 604 * to clear them, as they are edge-triggered. 605 */ 606 void hdec_interrupt(struct pt_regs *regs) 607 { 608 } 609 610 #ifdef CONFIG_SUSPEND 611 static void generic_suspend_disable_irqs(void) 612 { 613 /* Disable the decrementer, so that it doesn't interfere 614 * with suspending. 615 */ 616 617 set_dec(decrementer_max); 618 local_irq_disable(); 619 set_dec(decrementer_max); 620 } 621 622 static void generic_suspend_enable_irqs(void) 623 { 624 local_irq_enable(); 625 } 626 627 /* Overrides the weak version in kernel/power/main.c */ 628 void arch_suspend_disable_irqs(void) 629 { 630 if (ppc_md.suspend_disable_irqs) 631 ppc_md.suspend_disable_irqs(); 632 generic_suspend_disable_irqs(); 633 } 634 635 /* Overrides the weak version in kernel/power/main.c */ 636 void arch_suspend_enable_irqs(void) 637 { 638 generic_suspend_enable_irqs(); 639 if (ppc_md.suspend_enable_irqs) 640 ppc_md.suspend_enable_irqs(); 641 } 642 #endif 643 644 unsigned long long tb_to_ns(unsigned long long ticks) 645 { 646 return mulhdu(ticks, tb_to_ns_scale) << tb_to_ns_shift; 647 } 648 EXPORT_SYMBOL_GPL(tb_to_ns); 649 650 /* 651 * Scheduler clock - returns current time in nanosec units. 652 * 653 * Note: mulhdu(a, b) (multiply high double unsigned) returns 654 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 655 * are 64-bit unsigned numbers. 656 */ 657 unsigned long long sched_clock(void) 658 { 659 if (__USE_RTC()) 660 return get_rtc(); 661 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 662 } 663 664 665 #ifdef CONFIG_PPC_PSERIES 666 667 /* 668 * Running clock - attempts to give a view of time passing for a virtualised 669 * kernels. 670 * Uses the VTB register if available otherwise a next best guess. 671 */ 672 unsigned long long running_clock(void) 673 { 674 /* 675 * Don't read the VTB as a host since KVM does not switch in host 676 * timebase into the VTB when it takes a guest off the CPU, reading the 677 * VTB would result in reading 'last switched out' guest VTB. 678 * 679 * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it 680 * would be unsafe to rely only on the #ifdef above. 681 */ 682 if (firmware_has_feature(FW_FEATURE_LPAR) && 683 cpu_has_feature(CPU_FTR_ARCH_207S)) 684 return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 685 686 /* 687 * This is a next best approximation without a VTB. 688 * On a host which is running bare metal there should never be any stolen 689 * time and on a host which doesn't do any virtualisation TB *should* equal 690 * VTB so it makes no difference anyway. 691 */ 692 return local_clock() - cputime_to_nsecs(kcpustat_this_cpu->cpustat[CPUTIME_STEAL]); 693 } 694 #endif 695 696 static int __init get_freq(char *name, int cells, unsigned long *val) 697 { 698 struct device_node *cpu; 699 const __be32 *fp; 700 int found = 0; 701 702 /* The cpu node should have timebase and clock frequency properties */ 703 cpu = of_find_node_by_type(NULL, "cpu"); 704 705 if (cpu) { 706 fp = of_get_property(cpu, name, NULL); 707 if (fp) { 708 found = 1; 709 *val = of_read_ulong(fp, cells); 710 } 711 712 of_node_put(cpu); 713 } 714 715 return found; 716 } 717 718 static void start_cpu_decrementer(void) 719 { 720 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) 721 /* Clear any pending timer interrupts */ 722 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 723 724 /* Enable decrementer interrupt */ 725 mtspr(SPRN_TCR, TCR_DIE); 726 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */ 727 } 728 729 void __init generic_calibrate_decr(void) 730 { 731 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 732 733 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 734 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 735 736 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 737 "(not found)\n"); 738 } 739 740 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 741 742 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 743 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 744 745 printk(KERN_ERR "WARNING: Estimating processor frequency " 746 "(not found)\n"); 747 } 748 } 749 750 int update_persistent_clock(struct timespec now) 751 { 752 struct rtc_time tm; 753 754 if (!ppc_md.set_rtc_time) 755 return -ENODEV; 756 757 to_tm(now.tv_sec + 1 + timezone_offset, &tm); 758 tm.tm_year -= 1900; 759 tm.tm_mon -= 1; 760 761 return ppc_md.set_rtc_time(&tm); 762 } 763 764 static void __read_persistent_clock(struct timespec *ts) 765 { 766 struct rtc_time tm; 767 static int first = 1; 768 769 ts->tv_nsec = 0; 770 /* XXX this is a litle fragile but will work okay in the short term */ 771 if (first) { 772 first = 0; 773 if (ppc_md.time_init) 774 timezone_offset = ppc_md.time_init(); 775 776 /* get_boot_time() isn't guaranteed to be safe to call late */ 777 if (ppc_md.get_boot_time) { 778 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 779 return; 780 } 781 } 782 if (!ppc_md.get_rtc_time) { 783 ts->tv_sec = 0; 784 return; 785 } 786 ppc_md.get_rtc_time(&tm); 787 788 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, 789 tm.tm_hour, tm.tm_min, tm.tm_sec); 790 } 791 792 void read_persistent_clock(struct timespec *ts) 793 { 794 __read_persistent_clock(ts); 795 796 /* Sanitize it in case real time clock is set below EPOCH */ 797 if (ts->tv_sec < 0) { 798 ts->tv_sec = 0; 799 ts->tv_nsec = 0; 800 } 801 802 } 803 804 /* clocksource code */ 805 static cycle_t rtc_read(struct clocksource *cs) 806 { 807 return (cycle_t)get_rtc(); 808 } 809 810 static cycle_t timebase_read(struct clocksource *cs) 811 { 812 return (cycle_t)get_tb(); 813 } 814 815 void update_vsyscall_old(struct timespec *wall_time, struct timespec *wtm, 816 struct clocksource *clock, u32 mult, cycle_t cycle_last) 817 { 818 u64 new_tb_to_xs, new_stamp_xsec; 819 u32 frac_sec; 820 821 if (clock != &clocksource_timebase) 822 return; 823 824 /* Make userspace gettimeofday spin until we're done. */ 825 ++vdso_data->tb_update_count; 826 smp_mb(); 827 828 /* 19342813113834067 ~= 2^(20+64) / 1e9 */ 829 new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift); 830 new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC; 831 do_div(new_stamp_xsec, 1000000000); 832 new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC; 833 834 BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC); 835 /* this is tv_nsec / 1e9 as a 0.32 fraction */ 836 frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32; 837 838 /* 839 * tb_update_count is used to allow the userspace gettimeofday code 840 * to assure itself that it sees a consistent view of the tb_to_xs and 841 * stamp_xsec variables. It reads the tb_update_count, then reads 842 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If 843 * the two values of tb_update_count match and are even then the 844 * tb_to_xs and stamp_xsec values are consistent. If not, then it 845 * loops back and reads them again until this criteria is met. 846 * We expect the caller to have done the first increment of 847 * vdso_data->tb_update_count already. 848 */ 849 vdso_data->tb_orig_stamp = cycle_last; 850 vdso_data->stamp_xsec = new_stamp_xsec; 851 vdso_data->tb_to_xs = new_tb_to_xs; 852 vdso_data->wtom_clock_sec = wtm->tv_sec; 853 vdso_data->wtom_clock_nsec = wtm->tv_nsec; 854 vdso_data->stamp_xtime = *wall_time; 855 vdso_data->stamp_sec_fraction = frac_sec; 856 smp_wmb(); 857 ++(vdso_data->tb_update_count); 858 } 859 860 void update_vsyscall_tz(void) 861 { 862 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; 863 vdso_data->tz_dsttime = sys_tz.tz_dsttime; 864 } 865 866 static void __init clocksource_init(void) 867 { 868 struct clocksource *clock; 869 870 if (__USE_RTC()) 871 clock = &clocksource_rtc; 872 else 873 clock = &clocksource_timebase; 874 875 if (clocksource_register_hz(clock, tb_ticks_per_sec)) { 876 printk(KERN_ERR "clocksource: %s is already registered\n", 877 clock->name); 878 return; 879 } 880 881 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 882 clock->name, clock->mult, clock->shift); 883 } 884 885 static int decrementer_set_next_event(unsigned long evt, 886 struct clock_event_device *dev) 887 { 888 __this_cpu_write(decrementers_next_tb, get_tb_or_rtc() + evt); 889 set_dec(evt); 890 891 /* We may have raced with new irq work */ 892 if (test_irq_work_pending()) 893 set_dec(1); 894 895 return 0; 896 } 897 898 static int decrementer_shutdown(struct clock_event_device *dev) 899 { 900 decrementer_set_next_event(decrementer_max, dev); 901 return 0; 902 } 903 904 /* Interrupt handler for the timer broadcast IPI */ 905 void tick_broadcast_ipi_handler(void) 906 { 907 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 908 909 *next_tb = get_tb_or_rtc(); 910 __timer_interrupt(); 911 } 912 913 static void register_decrementer_clockevent(int cpu) 914 { 915 struct clock_event_device *dec = &per_cpu(decrementers, cpu); 916 917 *dec = decrementer_clockevent; 918 dec->cpumask = cpumask_of(cpu); 919 920 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 921 dec->name, dec->mult, dec->shift, cpu); 922 923 clockevents_register_device(dec); 924 } 925 926 static void enable_large_decrementer(void) 927 { 928 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 929 return; 930 931 if (decrementer_max <= DECREMENTER_DEFAULT_MAX) 932 return; 933 934 /* 935 * If we're running as the hypervisor we need to enable the LD manually 936 * otherwise firmware should have done it for us. 937 */ 938 if (cpu_has_feature(CPU_FTR_HVMODE)) 939 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_LD); 940 } 941 942 static void __init set_decrementer_max(void) 943 { 944 struct device_node *cpu; 945 u32 bits = 32; 946 947 /* Prior to ISAv3 the decrementer is always 32 bit */ 948 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 949 return; 950 951 cpu = of_find_node_by_type(NULL, "cpu"); 952 953 if (of_property_read_u32(cpu, "ibm,dec-bits", &bits) == 0) { 954 if (bits > 64 || bits < 32) { 955 pr_warn("time_init: firmware supplied invalid ibm,dec-bits"); 956 bits = 32; 957 } 958 959 /* calculate the signed maximum given this many bits */ 960 decrementer_max = (1ul << (bits - 1)) - 1; 961 } 962 963 of_node_put(cpu); 964 965 pr_info("time_init: %u bit decrementer (max: %llx)\n", 966 bits, decrementer_max); 967 } 968 969 static void __init init_decrementer_clockevent(void) 970 { 971 int cpu = smp_processor_id(); 972 973 clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4); 974 975 decrementer_clockevent.max_delta_ns = 976 clockevent_delta2ns(decrementer_max, &decrementer_clockevent); 977 decrementer_clockevent.min_delta_ns = 978 clockevent_delta2ns(2, &decrementer_clockevent); 979 980 register_decrementer_clockevent(cpu); 981 } 982 983 void secondary_cpu_time_init(void) 984 { 985 /* Enable and test the large decrementer for this cpu */ 986 enable_large_decrementer(); 987 988 /* Start the decrementer on CPUs that have manual control 989 * such as BookE 990 */ 991 start_cpu_decrementer(); 992 993 /* FIME: Should make unrelatred change to move snapshot_timebase 994 * call here ! */ 995 register_decrementer_clockevent(smp_processor_id()); 996 } 997 998 /* This function is only called on the boot processor */ 999 void __init time_init(void) 1000 { 1001 struct div_result res; 1002 u64 scale; 1003 unsigned shift; 1004 1005 if (__USE_RTC()) { 1006 /* 601 processor: dec counts down by 128 every 128ns */ 1007 ppc_tb_freq = 1000000000; 1008 } else { 1009 /* Normal PowerPC with timebase register */ 1010 ppc_md.calibrate_decr(); 1011 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 1012 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 1013 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 1014 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 1015 } 1016 1017 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 1018 tb_ticks_per_sec = ppc_tb_freq; 1019 tb_ticks_per_usec = ppc_tb_freq / 1000000; 1020 calc_cputime_factors(); 1021 setup_cputime_one_jiffy(); 1022 1023 /* 1024 * Compute scale factor for sched_clock. 1025 * The calibrate_decr() function has set tb_ticks_per_sec, 1026 * which is the timebase frequency. 1027 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 1028 * the 128-bit result as a 64.64 fixed-point number. 1029 * We then shift that number right until it is less than 1.0, 1030 * giving us the scale factor and shift count to use in 1031 * sched_clock(). 1032 */ 1033 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 1034 scale = res.result_low; 1035 for (shift = 0; res.result_high != 0; ++shift) { 1036 scale = (scale >> 1) | (res.result_high << 63); 1037 res.result_high >>= 1; 1038 } 1039 tb_to_ns_scale = scale; 1040 tb_to_ns_shift = shift; 1041 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 1042 boot_tb = get_tb_or_rtc(); 1043 1044 /* If platform provided a timezone (pmac), we correct the time */ 1045 if (timezone_offset) { 1046 sys_tz.tz_minuteswest = -timezone_offset / 60; 1047 sys_tz.tz_dsttime = 0; 1048 } 1049 1050 vdso_data->tb_update_count = 0; 1051 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 1052 1053 /* initialise and enable the large decrementer (if we have one) */ 1054 set_decrementer_max(); 1055 enable_large_decrementer(); 1056 1057 /* Start the decrementer on CPUs that have manual control 1058 * such as BookE 1059 */ 1060 start_cpu_decrementer(); 1061 1062 /* Register the clocksource */ 1063 clocksource_init(); 1064 1065 init_decrementer_clockevent(); 1066 tick_setup_hrtimer_broadcast(); 1067 1068 #ifdef CONFIG_COMMON_CLK 1069 of_clk_init(NULL); 1070 #endif 1071 } 1072 1073 1074 #define FEBRUARY 2 1075 #define STARTOFTIME 1970 1076 #define SECDAY 86400L 1077 #define SECYR (SECDAY * 365) 1078 #define leapyear(year) ((year) % 4 == 0 && \ 1079 ((year) % 100 != 0 || (year) % 400 == 0)) 1080 #define days_in_year(a) (leapyear(a) ? 366 : 365) 1081 #define days_in_month(a) (month_days[(a) - 1]) 1082 1083 static int month_days[12] = { 1084 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 1085 }; 1086 1087 void to_tm(int tim, struct rtc_time * tm) 1088 { 1089 register int i; 1090 register long hms, day; 1091 1092 day = tim / SECDAY; 1093 hms = tim % SECDAY; 1094 1095 /* Hours, minutes, seconds are easy */ 1096 tm->tm_hour = hms / 3600; 1097 tm->tm_min = (hms % 3600) / 60; 1098 tm->tm_sec = (hms % 3600) % 60; 1099 1100 /* Number of years in days */ 1101 for (i = STARTOFTIME; day >= days_in_year(i); i++) 1102 day -= days_in_year(i); 1103 tm->tm_year = i; 1104 1105 /* Number of months in days left */ 1106 if (leapyear(tm->tm_year)) 1107 days_in_month(FEBRUARY) = 29; 1108 for (i = 1; day >= days_in_month(i); i++) 1109 day -= days_in_month(i); 1110 days_in_month(FEBRUARY) = 28; 1111 tm->tm_mon = i; 1112 1113 /* Days are what is left over (+1) from all that. */ 1114 tm->tm_mday = day + 1; 1115 1116 /* 1117 * No-one uses the day of the week. 1118 */ 1119 tm->tm_wday = -1; 1120 } 1121 EXPORT_SYMBOL(to_tm); 1122 1123 /* 1124 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 1125 * result. 1126 */ 1127 void div128_by_32(u64 dividend_high, u64 dividend_low, 1128 unsigned divisor, struct div_result *dr) 1129 { 1130 unsigned long a, b, c, d; 1131 unsigned long w, x, y, z; 1132 u64 ra, rb, rc; 1133 1134 a = dividend_high >> 32; 1135 b = dividend_high & 0xffffffff; 1136 c = dividend_low >> 32; 1137 d = dividend_low & 0xffffffff; 1138 1139 w = a / divisor; 1140 ra = ((u64)(a - (w * divisor)) << 32) + b; 1141 1142 rb = ((u64) do_div(ra, divisor) << 32) + c; 1143 x = ra; 1144 1145 rc = ((u64) do_div(rb, divisor) << 32) + d; 1146 y = rb; 1147 1148 do_div(rc, divisor); 1149 z = rc; 1150 1151 dr->result_high = ((u64)w << 32) + x; 1152 dr->result_low = ((u64)y << 32) + z; 1153 1154 } 1155 1156 /* We don't need to calibrate delay, we use the CPU timebase for that */ 1157 void calibrate_delay(void) 1158 { 1159 /* Some generic code (such as spinlock debug) use loops_per_jiffy 1160 * as the number of __delay(1) in a jiffy, so make it so 1161 */ 1162 loops_per_jiffy = tb_ticks_per_jiffy; 1163 } 1164 1165 #if IS_ENABLED(CONFIG_RTC_DRV_GENERIC) 1166 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm) 1167 { 1168 ppc_md.get_rtc_time(tm); 1169 return rtc_valid_tm(tm); 1170 } 1171 1172 static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm) 1173 { 1174 if (!ppc_md.set_rtc_time) 1175 return -EOPNOTSUPP; 1176 1177 if (ppc_md.set_rtc_time(tm) < 0) 1178 return -EOPNOTSUPP; 1179 1180 return 0; 1181 } 1182 1183 static const struct rtc_class_ops rtc_generic_ops = { 1184 .read_time = rtc_generic_get_time, 1185 .set_time = rtc_generic_set_time, 1186 }; 1187 1188 static int __init rtc_init(void) 1189 { 1190 struct platform_device *pdev; 1191 1192 if (!ppc_md.get_rtc_time) 1193 return -ENODEV; 1194 1195 pdev = platform_device_register_data(NULL, "rtc-generic", -1, 1196 &rtc_generic_ops, 1197 sizeof(rtc_generic_ops)); 1198 1199 return PTR_ERR_OR_ZERO(pdev); 1200 } 1201 1202 device_initcall(rtc_init); 1203 #endif 1204