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 <linux/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 u64 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 u64 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); 167 168 cputime_t cputime_one_jiffy; 169 170 #ifdef CONFIG_PPC_SPLPAR 171 void (*dtl_consumer)(struct dtl_entry *, u64); 172 #endif 173 174 #ifdef CONFIG_PPC64 175 #define get_accounting(tsk) (&get_paca()->accounting) 176 #else 177 #define get_accounting(tsk) (&task_thread_info(tsk)->accounting) 178 #endif 179 180 static void calc_cputime_factors(void) 181 { 182 struct div_result res; 183 184 div128_by_32(HZ, 0, tb_ticks_per_sec, &res); 185 __cputime_jiffies_factor = res.result_low; 186 div128_by_32(1000000, 0, tb_ticks_per_sec, &res); 187 __cputime_usec_factor = res.result_low; 188 div128_by_32(1, 0, tb_ticks_per_sec, &res); 189 __cputime_sec_factor = res.result_low; 190 div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res); 191 __cputime_clockt_factor = res.result_low; 192 } 193 194 /* 195 * Read the SPURR on systems that have it, otherwise the PURR, 196 * or if that doesn't exist return the timebase value passed in. 197 */ 198 static unsigned long read_spurr(unsigned long tb) 199 { 200 if (cpu_has_feature(CPU_FTR_SPURR)) 201 return mfspr(SPRN_SPURR); 202 if (cpu_has_feature(CPU_FTR_PURR)) 203 return mfspr(SPRN_PURR); 204 return tb; 205 } 206 207 #ifdef CONFIG_PPC_SPLPAR 208 209 /* 210 * Scan the dispatch trace log and count up the stolen time. 211 * Should be called with interrupts disabled. 212 */ 213 static u64 scan_dispatch_log(u64 stop_tb) 214 { 215 u64 i = local_paca->dtl_ridx; 216 struct dtl_entry *dtl = local_paca->dtl_curr; 217 struct dtl_entry *dtl_end = local_paca->dispatch_log_end; 218 struct lppaca *vpa = local_paca->lppaca_ptr; 219 u64 tb_delta; 220 u64 stolen = 0; 221 u64 dtb; 222 223 if (!dtl) 224 return 0; 225 226 if (i == be64_to_cpu(vpa->dtl_idx)) 227 return 0; 228 while (i < be64_to_cpu(vpa->dtl_idx)) { 229 dtb = be64_to_cpu(dtl->timebase); 230 tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) + 231 be32_to_cpu(dtl->ready_to_enqueue_time); 232 barrier(); 233 if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) { 234 /* buffer has overflowed */ 235 i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG; 236 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG); 237 continue; 238 } 239 if (dtb > stop_tb) 240 break; 241 if (dtl_consumer) 242 dtl_consumer(dtl, i); 243 stolen += tb_delta; 244 ++i; 245 ++dtl; 246 if (dtl == dtl_end) 247 dtl = local_paca->dispatch_log; 248 } 249 local_paca->dtl_ridx = i; 250 local_paca->dtl_curr = dtl; 251 return stolen; 252 } 253 254 /* 255 * Accumulate stolen time by scanning the dispatch trace log. 256 * Called on entry from user mode. 257 */ 258 void accumulate_stolen_time(void) 259 { 260 u64 sst, ust; 261 u8 save_soft_enabled = local_paca->soft_enabled; 262 struct cpu_accounting_data *acct = &local_paca->accounting; 263 264 /* We are called early in the exception entry, before 265 * soft/hard_enabled are sync'ed to the expected state 266 * for the exception. We are hard disabled but the PACA 267 * needs to reflect that so various debug stuff doesn't 268 * complain 269 */ 270 local_paca->soft_enabled = 0; 271 272 sst = scan_dispatch_log(acct->starttime_user); 273 ust = scan_dispatch_log(acct->starttime); 274 acct->stime -= sst; 275 acct->utime -= ust; 276 acct->steal_time += ust + sst; 277 278 local_paca->soft_enabled = save_soft_enabled; 279 } 280 281 static inline u64 calculate_stolen_time(u64 stop_tb) 282 { 283 u64 stolen = 0; 284 struct cpu_accounting_data *acct = &local_paca->accounting; 285 286 if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx)) { 287 stolen = scan_dispatch_log(stop_tb); 288 acct->stime -= stolen; 289 } 290 291 stolen += acct->steal_time; 292 acct->steal_time = 0; 293 return stolen; 294 } 295 296 #else /* CONFIG_PPC_SPLPAR */ 297 static inline u64 calculate_stolen_time(u64 stop_tb) 298 { 299 return 0; 300 } 301 302 #endif /* CONFIG_PPC_SPLPAR */ 303 304 /* 305 * Account time for a transition between system, hard irq 306 * or soft irq state. 307 */ 308 static unsigned long vtime_delta(struct task_struct *tsk, 309 unsigned long *sys_scaled, 310 unsigned long *stolen) 311 { 312 unsigned long now, nowscaled, deltascaled; 313 unsigned long udelta, delta, user_scaled; 314 struct cpu_accounting_data *acct = get_accounting(tsk); 315 316 WARN_ON_ONCE(!irqs_disabled()); 317 318 now = mftb(); 319 nowscaled = read_spurr(now); 320 acct->stime += now - acct->starttime; 321 acct->starttime = now; 322 deltascaled = nowscaled - acct->startspurr; 323 acct->startspurr = nowscaled; 324 325 *stolen = calculate_stolen_time(now); 326 327 delta = acct->stime; 328 acct->stime = 0; 329 udelta = acct->utime - acct->utime_sspurr; 330 acct->utime_sspurr = acct->utime; 331 332 /* 333 * Because we don't read the SPURR on every kernel entry/exit, 334 * deltascaled includes both user and system SPURR ticks. 335 * Apportion these ticks to system SPURR ticks and user 336 * SPURR ticks in the same ratio as the system time (delta) 337 * and user time (udelta) values obtained from the timebase 338 * over the same interval. The system ticks get accounted here; 339 * the user ticks get saved up in paca->user_time_scaled to be 340 * used by account_process_tick. 341 */ 342 *sys_scaled = delta; 343 user_scaled = udelta; 344 if (deltascaled != delta + udelta) { 345 if (udelta) { 346 *sys_scaled = deltascaled * delta / (delta + udelta); 347 user_scaled = deltascaled - *sys_scaled; 348 } else { 349 *sys_scaled = deltascaled; 350 } 351 } 352 acct->utime_scaled += user_scaled; 353 354 return delta; 355 } 356 357 void vtime_account_system(struct task_struct *tsk) 358 { 359 unsigned long delta, sys_scaled, stolen; 360 361 delta = vtime_delta(tsk, &sys_scaled, &stolen); 362 account_system_time(tsk, 0, delta); 363 tsk->stimescaled += 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->utime; 392 utimescaled = acct->utime_scaled; 393 acct->utime = 0; 394 acct->utime_scaled = 0; 395 acct->utime_sspurr = 0; 396 account_user_time(tsk, utime); 397 tsk->utimescaled += utimescaled; 398 } 399 400 #ifdef CONFIG_PPC32 401 /* 402 * Called from the context switch with interrupts disabled, to charge all 403 * accumulated times to the current process, and to prepare accounting on 404 * the next process. 405 */ 406 void arch_vtime_task_switch(struct task_struct *prev) 407 { 408 struct cpu_accounting_data *acct = get_accounting(current); 409 410 acct->starttime = get_accounting(prev)->starttime; 411 acct->startspurr = get_accounting(prev)->startspurr; 412 acct->stime = 0; 413 acct->utime = 0; 414 } 415 #endif /* CONFIG_PPC32 */ 416 417 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ 418 #define calc_cputime_factors() 419 #endif 420 421 void __delay(unsigned long loops) 422 { 423 unsigned long start; 424 int diff; 425 426 if (__USE_RTC()) { 427 start = get_rtcl(); 428 do { 429 /* the RTCL register wraps at 1000000000 */ 430 diff = get_rtcl() - start; 431 if (diff < 0) 432 diff += 1000000000; 433 } while (diff < loops); 434 } else { 435 start = get_tbl(); 436 while (get_tbl() - start < loops) 437 HMT_low(); 438 HMT_medium(); 439 } 440 } 441 EXPORT_SYMBOL(__delay); 442 443 void udelay(unsigned long usecs) 444 { 445 __delay(tb_ticks_per_usec * usecs); 446 } 447 EXPORT_SYMBOL(udelay); 448 449 #ifdef CONFIG_SMP 450 unsigned long profile_pc(struct pt_regs *regs) 451 { 452 unsigned long pc = instruction_pointer(regs); 453 454 if (in_lock_functions(pc)) 455 return regs->link; 456 457 return pc; 458 } 459 EXPORT_SYMBOL(profile_pc); 460 #endif 461 462 #ifdef CONFIG_IRQ_WORK 463 464 /* 465 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable... 466 */ 467 #ifdef CONFIG_PPC64 468 static inline unsigned long test_irq_work_pending(void) 469 { 470 unsigned long x; 471 472 asm volatile("lbz %0,%1(13)" 473 : "=r" (x) 474 : "i" (offsetof(struct paca_struct, irq_work_pending))); 475 return x; 476 } 477 478 static inline void set_irq_work_pending_flag(void) 479 { 480 asm volatile("stb %0,%1(13)" : : 481 "r" (1), 482 "i" (offsetof(struct paca_struct, irq_work_pending))); 483 } 484 485 static inline void clear_irq_work_pending(void) 486 { 487 asm volatile("stb %0,%1(13)" : : 488 "r" (0), 489 "i" (offsetof(struct paca_struct, irq_work_pending))); 490 } 491 492 #else /* 32-bit */ 493 494 DEFINE_PER_CPU(u8, irq_work_pending); 495 496 #define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1) 497 #define test_irq_work_pending() __this_cpu_read(irq_work_pending) 498 #define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0) 499 500 #endif /* 32 vs 64 bit */ 501 502 void arch_irq_work_raise(void) 503 { 504 preempt_disable(); 505 set_irq_work_pending_flag(); 506 set_dec(1); 507 preempt_enable(); 508 } 509 510 #else /* CONFIG_IRQ_WORK */ 511 512 #define test_irq_work_pending() 0 513 #define clear_irq_work_pending() 514 515 #endif /* CONFIG_IRQ_WORK */ 516 517 static void __timer_interrupt(void) 518 { 519 struct pt_regs *regs = get_irq_regs(); 520 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 521 struct clock_event_device *evt = this_cpu_ptr(&decrementers); 522 u64 now; 523 524 trace_timer_interrupt_entry(regs); 525 526 if (test_irq_work_pending()) { 527 clear_irq_work_pending(); 528 irq_work_run(); 529 } 530 531 now = get_tb_or_rtc(); 532 if (now >= *next_tb) { 533 *next_tb = ~(u64)0; 534 if (evt->event_handler) 535 evt->event_handler(evt); 536 __this_cpu_inc(irq_stat.timer_irqs_event); 537 } else { 538 now = *next_tb - now; 539 if (now <= decrementer_max) 540 set_dec(now); 541 /* We may have raced with new irq work */ 542 if (test_irq_work_pending()) 543 set_dec(1); 544 __this_cpu_inc(irq_stat.timer_irqs_others); 545 } 546 547 #ifdef CONFIG_PPC64 548 /* collect purr register values often, for accurate calculations */ 549 if (firmware_has_feature(FW_FEATURE_SPLPAR)) { 550 struct cpu_usage *cu = this_cpu_ptr(&cpu_usage_array); 551 cu->current_tb = mfspr(SPRN_PURR); 552 } 553 #endif 554 555 trace_timer_interrupt_exit(regs); 556 } 557 558 /* 559 * timer_interrupt - gets called when the decrementer overflows, 560 * with interrupts disabled. 561 */ 562 void timer_interrupt(struct pt_regs * regs) 563 { 564 struct pt_regs *old_regs; 565 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 566 567 /* Ensure a positive value is written to the decrementer, or else 568 * some CPUs will continue to take decrementer exceptions. 569 */ 570 set_dec(decrementer_max); 571 572 /* Some implementations of hotplug will get timer interrupts while 573 * offline, just ignore these and we also need to set 574 * decrementers_next_tb as MAX to make sure __check_irq_replay 575 * don't replay timer interrupt when return, otherwise we'll trap 576 * here infinitely :( 577 */ 578 if (!cpu_online(smp_processor_id())) { 579 *next_tb = ~(u64)0; 580 return; 581 } 582 583 /* Conditionally hard-enable interrupts now that the DEC has been 584 * bumped to its maximum value 585 */ 586 may_hard_irq_enable(); 587 588 589 #if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC) 590 if (atomic_read(&ppc_n_lost_interrupts) != 0) 591 do_IRQ(regs); 592 #endif 593 594 old_regs = set_irq_regs(regs); 595 irq_enter(); 596 597 __timer_interrupt(); 598 irq_exit(); 599 set_irq_regs(old_regs); 600 } 601 EXPORT_SYMBOL(timer_interrupt); 602 603 /* 604 * Hypervisor decrementer interrupts shouldn't occur but are sometimes 605 * left pending on exit from a KVM guest. We don't need to do anything 606 * to clear them, as they are edge-triggered. 607 */ 608 void hdec_interrupt(struct pt_regs *regs) 609 { 610 } 611 612 #ifdef CONFIG_SUSPEND 613 static void generic_suspend_disable_irqs(void) 614 { 615 /* Disable the decrementer, so that it doesn't interfere 616 * with suspending. 617 */ 618 619 set_dec(decrementer_max); 620 local_irq_disable(); 621 set_dec(decrementer_max); 622 } 623 624 static void generic_suspend_enable_irqs(void) 625 { 626 local_irq_enable(); 627 } 628 629 /* Overrides the weak version in kernel/power/main.c */ 630 void arch_suspend_disable_irqs(void) 631 { 632 if (ppc_md.suspend_disable_irqs) 633 ppc_md.suspend_disable_irqs(); 634 generic_suspend_disable_irqs(); 635 } 636 637 /* Overrides the weak version in kernel/power/main.c */ 638 void arch_suspend_enable_irqs(void) 639 { 640 generic_suspend_enable_irqs(); 641 if (ppc_md.suspend_enable_irqs) 642 ppc_md.suspend_enable_irqs(); 643 } 644 #endif 645 646 unsigned long long tb_to_ns(unsigned long long ticks) 647 { 648 return mulhdu(ticks, tb_to_ns_scale) << tb_to_ns_shift; 649 } 650 EXPORT_SYMBOL_GPL(tb_to_ns); 651 652 /* 653 * Scheduler clock - returns current time in nanosec units. 654 * 655 * Note: mulhdu(a, b) (multiply high double unsigned) returns 656 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 657 * are 64-bit unsigned numbers. 658 */ 659 unsigned long long sched_clock(void) 660 { 661 if (__USE_RTC()) 662 return get_rtc(); 663 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 664 } 665 666 667 #ifdef CONFIG_PPC_PSERIES 668 669 /* 670 * Running clock - attempts to give a view of time passing for a virtualised 671 * kernels. 672 * Uses the VTB register if available otherwise a next best guess. 673 */ 674 unsigned long long running_clock(void) 675 { 676 /* 677 * Don't read the VTB as a host since KVM does not switch in host 678 * timebase into the VTB when it takes a guest off the CPU, reading the 679 * VTB would result in reading 'last switched out' guest VTB. 680 * 681 * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it 682 * would be unsafe to rely only on the #ifdef above. 683 */ 684 if (firmware_has_feature(FW_FEATURE_LPAR) && 685 cpu_has_feature(CPU_FTR_ARCH_207S)) 686 return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 687 688 /* 689 * This is a next best approximation without a VTB. 690 * On a host which is running bare metal there should never be any stolen 691 * time and on a host which doesn't do any virtualisation TB *should* equal 692 * VTB so it makes no difference anyway. 693 */ 694 return local_clock() - cputime_to_nsecs(kcpustat_this_cpu->cpustat[CPUTIME_STEAL]); 695 } 696 #endif 697 698 static int __init get_freq(char *name, int cells, unsigned long *val) 699 { 700 struct device_node *cpu; 701 const __be32 *fp; 702 int found = 0; 703 704 /* The cpu node should have timebase and clock frequency properties */ 705 cpu = of_find_node_by_type(NULL, "cpu"); 706 707 if (cpu) { 708 fp = of_get_property(cpu, name, NULL); 709 if (fp) { 710 found = 1; 711 *val = of_read_ulong(fp, cells); 712 } 713 714 of_node_put(cpu); 715 } 716 717 return found; 718 } 719 720 static void start_cpu_decrementer(void) 721 { 722 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) 723 /* Clear any pending timer interrupts */ 724 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 725 726 /* Enable decrementer interrupt */ 727 mtspr(SPRN_TCR, TCR_DIE); 728 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */ 729 } 730 731 void __init generic_calibrate_decr(void) 732 { 733 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 734 735 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 736 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 737 738 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 739 "(not found)\n"); 740 } 741 742 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 743 744 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 745 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 746 747 printk(KERN_ERR "WARNING: Estimating processor frequency " 748 "(not found)\n"); 749 } 750 } 751 752 int update_persistent_clock(struct timespec now) 753 { 754 struct rtc_time tm; 755 756 if (!ppc_md.set_rtc_time) 757 return -ENODEV; 758 759 to_tm(now.tv_sec + 1 + timezone_offset, &tm); 760 tm.tm_year -= 1900; 761 tm.tm_mon -= 1; 762 763 return ppc_md.set_rtc_time(&tm); 764 } 765 766 static void __read_persistent_clock(struct timespec *ts) 767 { 768 struct rtc_time tm; 769 static int first = 1; 770 771 ts->tv_nsec = 0; 772 /* XXX this is a litle fragile but will work okay in the short term */ 773 if (first) { 774 first = 0; 775 if (ppc_md.time_init) 776 timezone_offset = ppc_md.time_init(); 777 778 /* get_boot_time() isn't guaranteed to be safe to call late */ 779 if (ppc_md.get_boot_time) { 780 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 781 return; 782 } 783 } 784 if (!ppc_md.get_rtc_time) { 785 ts->tv_sec = 0; 786 return; 787 } 788 ppc_md.get_rtc_time(&tm); 789 790 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, 791 tm.tm_hour, tm.tm_min, tm.tm_sec); 792 } 793 794 void read_persistent_clock(struct timespec *ts) 795 { 796 __read_persistent_clock(ts); 797 798 /* Sanitize it in case real time clock is set below EPOCH */ 799 if (ts->tv_sec < 0) { 800 ts->tv_sec = 0; 801 ts->tv_nsec = 0; 802 } 803 804 } 805 806 /* clocksource code */ 807 static u64 rtc_read(struct clocksource *cs) 808 { 809 return (u64)get_rtc(); 810 } 811 812 static u64 timebase_read(struct clocksource *cs) 813 { 814 return (u64)get_tb(); 815 } 816 817 void update_vsyscall_old(struct timespec *wall_time, struct timespec *wtm, 818 struct clocksource *clock, u32 mult, u64 cycle_last) 819 { 820 u64 new_tb_to_xs, new_stamp_xsec; 821 u32 frac_sec; 822 823 if (clock != &clocksource_timebase) 824 return; 825 826 /* Make userspace gettimeofday spin until we're done. */ 827 ++vdso_data->tb_update_count; 828 smp_mb(); 829 830 /* 19342813113834067 ~= 2^(20+64) / 1e9 */ 831 new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift); 832 new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC; 833 do_div(new_stamp_xsec, 1000000000); 834 new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC; 835 836 BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC); 837 /* this is tv_nsec / 1e9 as a 0.32 fraction */ 838 frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32; 839 840 /* 841 * tb_update_count is used to allow the userspace gettimeofday code 842 * to assure itself that it sees a consistent view of the tb_to_xs and 843 * stamp_xsec variables. It reads the tb_update_count, then reads 844 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If 845 * the two values of tb_update_count match and are even then the 846 * tb_to_xs and stamp_xsec values are consistent. If not, then it 847 * loops back and reads them again until this criteria is met. 848 * We expect the caller to have done the first increment of 849 * vdso_data->tb_update_count already. 850 */ 851 vdso_data->tb_orig_stamp = cycle_last; 852 vdso_data->stamp_xsec = new_stamp_xsec; 853 vdso_data->tb_to_xs = new_tb_to_xs; 854 vdso_data->wtom_clock_sec = wtm->tv_sec; 855 vdso_data->wtom_clock_nsec = wtm->tv_nsec; 856 vdso_data->stamp_xtime = *wall_time; 857 vdso_data->stamp_sec_fraction = frac_sec; 858 smp_wmb(); 859 ++(vdso_data->tb_update_count); 860 } 861 862 void update_vsyscall_tz(void) 863 { 864 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; 865 vdso_data->tz_dsttime = sys_tz.tz_dsttime; 866 } 867 868 static void __init clocksource_init(void) 869 { 870 struct clocksource *clock; 871 872 if (__USE_RTC()) 873 clock = &clocksource_rtc; 874 else 875 clock = &clocksource_timebase; 876 877 if (clocksource_register_hz(clock, tb_ticks_per_sec)) { 878 printk(KERN_ERR "clocksource: %s is already registered\n", 879 clock->name); 880 return; 881 } 882 883 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 884 clock->name, clock->mult, clock->shift); 885 } 886 887 static int decrementer_set_next_event(unsigned long evt, 888 struct clock_event_device *dev) 889 { 890 __this_cpu_write(decrementers_next_tb, get_tb_or_rtc() + evt); 891 set_dec(evt); 892 893 /* We may have raced with new irq work */ 894 if (test_irq_work_pending()) 895 set_dec(1); 896 897 return 0; 898 } 899 900 static int decrementer_shutdown(struct clock_event_device *dev) 901 { 902 decrementer_set_next_event(decrementer_max, dev); 903 return 0; 904 } 905 906 /* Interrupt handler for the timer broadcast IPI */ 907 void tick_broadcast_ipi_handler(void) 908 { 909 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 910 911 *next_tb = get_tb_or_rtc(); 912 __timer_interrupt(); 913 } 914 915 static void register_decrementer_clockevent(int cpu) 916 { 917 struct clock_event_device *dec = &per_cpu(decrementers, cpu); 918 919 *dec = decrementer_clockevent; 920 dec->cpumask = cpumask_of(cpu); 921 922 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 923 dec->name, dec->mult, dec->shift, cpu); 924 925 clockevents_register_device(dec); 926 } 927 928 static void enable_large_decrementer(void) 929 { 930 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 931 return; 932 933 if (decrementer_max <= DECREMENTER_DEFAULT_MAX) 934 return; 935 936 /* 937 * If we're running as the hypervisor we need to enable the LD manually 938 * otherwise firmware should have done it for us. 939 */ 940 if (cpu_has_feature(CPU_FTR_HVMODE)) 941 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_LD); 942 } 943 944 static void __init set_decrementer_max(void) 945 { 946 struct device_node *cpu; 947 u32 bits = 32; 948 949 /* Prior to ISAv3 the decrementer is always 32 bit */ 950 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 951 return; 952 953 cpu = of_find_node_by_type(NULL, "cpu"); 954 955 if (of_property_read_u32(cpu, "ibm,dec-bits", &bits) == 0) { 956 if (bits > 64 || bits < 32) { 957 pr_warn("time_init: firmware supplied invalid ibm,dec-bits"); 958 bits = 32; 959 } 960 961 /* calculate the signed maximum given this many bits */ 962 decrementer_max = (1ul << (bits - 1)) - 1; 963 } 964 965 of_node_put(cpu); 966 967 pr_info("time_init: %u bit decrementer (max: %llx)\n", 968 bits, decrementer_max); 969 } 970 971 static void __init init_decrementer_clockevent(void) 972 { 973 int cpu = smp_processor_id(); 974 975 clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4); 976 977 decrementer_clockevent.max_delta_ns = 978 clockevent_delta2ns(decrementer_max, &decrementer_clockevent); 979 decrementer_clockevent.min_delta_ns = 980 clockevent_delta2ns(2, &decrementer_clockevent); 981 982 register_decrementer_clockevent(cpu); 983 } 984 985 void secondary_cpu_time_init(void) 986 { 987 /* Enable and test the large decrementer for this cpu */ 988 enable_large_decrementer(); 989 990 /* Start the decrementer on CPUs that have manual control 991 * such as BookE 992 */ 993 start_cpu_decrementer(); 994 995 /* FIME: Should make unrelatred change to move snapshot_timebase 996 * call here ! */ 997 register_decrementer_clockevent(smp_processor_id()); 998 } 999 1000 /* This function is only called on the boot processor */ 1001 void __init time_init(void) 1002 { 1003 struct div_result res; 1004 u64 scale; 1005 unsigned shift; 1006 1007 if (__USE_RTC()) { 1008 /* 601 processor: dec counts down by 128 every 128ns */ 1009 ppc_tb_freq = 1000000000; 1010 } else { 1011 /* Normal PowerPC with timebase register */ 1012 ppc_md.calibrate_decr(); 1013 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 1014 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 1015 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 1016 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 1017 } 1018 1019 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 1020 tb_ticks_per_sec = ppc_tb_freq; 1021 tb_ticks_per_usec = ppc_tb_freq / 1000000; 1022 calc_cputime_factors(); 1023 setup_cputime_one_jiffy(); 1024 1025 /* 1026 * Compute scale factor for sched_clock. 1027 * The calibrate_decr() function has set tb_ticks_per_sec, 1028 * which is the timebase frequency. 1029 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 1030 * the 128-bit result as a 64.64 fixed-point number. 1031 * We then shift that number right until it is less than 1.0, 1032 * giving us the scale factor and shift count to use in 1033 * sched_clock(). 1034 */ 1035 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 1036 scale = res.result_low; 1037 for (shift = 0; res.result_high != 0; ++shift) { 1038 scale = (scale >> 1) | (res.result_high << 63); 1039 res.result_high >>= 1; 1040 } 1041 tb_to_ns_scale = scale; 1042 tb_to_ns_shift = shift; 1043 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 1044 boot_tb = get_tb_or_rtc(); 1045 1046 /* If platform provided a timezone (pmac), we correct the time */ 1047 if (timezone_offset) { 1048 sys_tz.tz_minuteswest = -timezone_offset / 60; 1049 sys_tz.tz_dsttime = 0; 1050 } 1051 1052 vdso_data->tb_update_count = 0; 1053 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 1054 1055 /* initialise and enable the large decrementer (if we have one) */ 1056 set_decrementer_max(); 1057 enable_large_decrementer(); 1058 1059 /* Start the decrementer on CPUs that have manual control 1060 * such as BookE 1061 */ 1062 start_cpu_decrementer(); 1063 1064 /* Register the clocksource */ 1065 clocksource_init(); 1066 1067 init_decrementer_clockevent(); 1068 tick_setup_hrtimer_broadcast(); 1069 1070 #ifdef CONFIG_COMMON_CLK 1071 of_clk_init(NULL); 1072 #endif 1073 } 1074 1075 1076 #define FEBRUARY 2 1077 #define STARTOFTIME 1970 1078 #define SECDAY 86400L 1079 #define SECYR (SECDAY * 365) 1080 #define leapyear(year) ((year) % 4 == 0 && \ 1081 ((year) % 100 != 0 || (year) % 400 == 0)) 1082 #define days_in_year(a) (leapyear(a) ? 366 : 365) 1083 #define days_in_month(a) (month_days[(a) - 1]) 1084 1085 static int month_days[12] = { 1086 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 1087 }; 1088 1089 void to_tm(int tim, struct rtc_time * tm) 1090 { 1091 register int i; 1092 register long hms, day; 1093 1094 day = tim / SECDAY; 1095 hms = tim % SECDAY; 1096 1097 /* Hours, minutes, seconds are easy */ 1098 tm->tm_hour = hms / 3600; 1099 tm->tm_min = (hms % 3600) / 60; 1100 tm->tm_sec = (hms % 3600) % 60; 1101 1102 /* Number of years in days */ 1103 for (i = STARTOFTIME; day >= days_in_year(i); i++) 1104 day -= days_in_year(i); 1105 tm->tm_year = i; 1106 1107 /* Number of months in days left */ 1108 if (leapyear(tm->tm_year)) 1109 days_in_month(FEBRUARY) = 29; 1110 for (i = 1; day >= days_in_month(i); i++) 1111 day -= days_in_month(i); 1112 days_in_month(FEBRUARY) = 28; 1113 tm->tm_mon = i; 1114 1115 /* Days are what is left over (+1) from all that. */ 1116 tm->tm_mday = day + 1; 1117 1118 /* 1119 * No-one uses the day of the week. 1120 */ 1121 tm->tm_wday = -1; 1122 } 1123 EXPORT_SYMBOL(to_tm); 1124 1125 /* 1126 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 1127 * result. 1128 */ 1129 void div128_by_32(u64 dividend_high, u64 dividend_low, 1130 unsigned divisor, struct div_result *dr) 1131 { 1132 unsigned long a, b, c, d; 1133 unsigned long w, x, y, z; 1134 u64 ra, rb, rc; 1135 1136 a = dividend_high >> 32; 1137 b = dividend_high & 0xffffffff; 1138 c = dividend_low >> 32; 1139 d = dividend_low & 0xffffffff; 1140 1141 w = a / divisor; 1142 ra = ((u64)(a - (w * divisor)) << 32) + b; 1143 1144 rb = ((u64) do_div(ra, divisor) << 32) + c; 1145 x = ra; 1146 1147 rc = ((u64) do_div(rb, divisor) << 32) + d; 1148 y = rb; 1149 1150 do_div(rc, divisor); 1151 z = rc; 1152 1153 dr->result_high = ((u64)w << 32) + x; 1154 dr->result_low = ((u64)y << 32) + z; 1155 1156 } 1157 1158 /* We don't need to calibrate delay, we use the CPU timebase for that */ 1159 void calibrate_delay(void) 1160 { 1161 /* Some generic code (such as spinlock debug) use loops_per_jiffy 1162 * as the number of __delay(1) in a jiffy, so make it so 1163 */ 1164 loops_per_jiffy = tb_ticks_per_jiffy; 1165 } 1166 1167 #if IS_ENABLED(CONFIG_RTC_DRV_GENERIC) 1168 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm) 1169 { 1170 ppc_md.get_rtc_time(tm); 1171 return rtc_valid_tm(tm); 1172 } 1173 1174 static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm) 1175 { 1176 if (!ppc_md.set_rtc_time) 1177 return -EOPNOTSUPP; 1178 1179 if (ppc_md.set_rtc_time(tm) < 0) 1180 return -EOPNOTSUPP; 1181 1182 return 0; 1183 } 1184 1185 static const struct rtc_class_ops rtc_generic_ops = { 1186 .read_time = rtc_generic_get_time, 1187 .set_time = rtc_generic_set_time, 1188 }; 1189 1190 static int __init rtc_init(void) 1191 { 1192 struct platform_device *pdev; 1193 1194 if (!ppc_md.get_rtc_time) 1195 return -ENODEV; 1196 1197 pdev = platform_device_register_data(NULL, "rtc-generic", -1, 1198 &rtc_generic_ops, 1199 sizeof(rtc_generic_ops)); 1200 1201 return PTR_ERR_OR_ZERO(pdev); 1202 } 1203 1204 device_initcall(rtc_init); 1205 #endif 1206