1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * Common time routines among all ppc machines. 4 * 5 * Written by Cort Dougan (cort@cs.nmt.edu) to merge 6 * Paul Mackerras' version and mine for PReP and Pmac. 7 * MPC8xx/MBX changes by Dan Malek (dmalek@jlc.net). 8 * Converted for 64-bit by Mike Corrigan (mikejc@us.ibm.com) 9 * 10 * First round of bugfixes by Gabriel Paubert (paubert@iram.es) 11 * to make clock more stable (2.4.0-test5). The only thing 12 * that this code assumes is that the timebases have been synchronized 13 * by firmware on SMP and are never stopped (never do sleep 14 * on SMP then, nap and doze are OK). 15 * 16 * Speeded up do_gettimeofday by getting rid of references to 17 * xtime (which required locks for consistency). (mikejc@us.ibm.com) 18 * 19 * TODO (not necessarily in this file): 20 * - improve precision and reproducibility of timebase frequency 21 * measurement at boot time. 22 * - for astronomical applications: add a new function to get 23 * non ambiguous timestamps even around leap seconds. This needs 24 * a new timestamp format and a good name. 25 * 26 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 27 * "A Kernel Model for Precision Timekeeping" by Dave Mills 28 */ 29 30#include <linux/errno.h> 31#include <linux/export.h> 32#include <linux/sched.h> 33#include <linux/sched/clock.h> 34#include <linux/sched/cputime.h> 35#include <linux/kernel.h> 36#include <linux/param.h> 37#include <linux/string.h> 38#include <linux/mm.h> 39#include <linux/interrupt.h> 40#include <linux/timex.h> 41#include <linux/kernel_stat.h> 42#include <linux/time.h> 43#include <linux/init.h> 44#include <linux/profile.h> 45#include <linux/cpu.h> 46#include <linux/security.h> 47#include <linux/percpu.h> 48#include <linux/rtc.h> 49#include <linux/jiffies.h> 50#include <linux/posix-timers.h> 51#include <linux/irq.h> 52#include <linux/delay.h> 53#include <linux/irq_work.h> 54#include <linux/of_clk.h> 55#include <linux/suspend.h> 56#include <linux/processor.h> 57#include <linux/mc146818rtc.h> 58#include <linux/platform_device.h> 59 60#include <asm/trace.h> 61#include <asm/interrupt.h> 62#include <asm/io.h> 63#include <asm/nvram.h> 64#include <asm/cache.h> 65#include <asm/machdep.h> 66#include <linux/uaccess.h> 67#include <asm/time.h> 68#include <asm/irq.h> 69#include <asm/div64.h> 70#include <asm/smp.h> 71#include <asm/vdso_datapage.h> 72#include <asm/firmware.h> 73#include <asm/mce.h> 74 75/* powerpc clocksource/clockevent code */ 76 77#include <linux/clockchips.h> 78#include <linux/timekeeper_internal.h> 79 80static u64 timebase_read(struct clocksource *); 81static struct clocksource clocksource_timebase = { 82 .name = "timebase", 83 .rating = 400, 84 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 85 .mask = CLOCKSOURCE_MASK(64), 86 .read = timebase_read, 87 .vdso_clock_mode = VDSO_CLOCKMODE_ARCHTIMER, 88}; 89 90#define DECREMENTER_DEFAULT_MAX 0x7FFFFFFF 91u64 decrementer_max = DECREMENTER_DEFAULT_MAX; 92EXPORT_SYMBOL_GPL(decrementer_max); /* for KVM HDEC */ 93 94static int decrementer_set_next_event(unsigned long evt, 95 struct clock_event_device *dev); 96static int decrementer_shutdown(struct clock_event_device *evt); 97 98struct clock_event_device decrementer_clockevent = { 99 .name = "decrementer", 100 .rating = 200, 101 .irq = 0, 102 .set_next_event = decrementer_set_next_event, 103 .set_state_oneshot_stopped = decrementer_shutdown, 104 .set_state_shutdown = decrementer_shutdown, 105 .tick_resume = decrementer_shutdown, 106 .features = CLOCK_EVT_FEAT_ONESHOT | 107 CLOCK_EVT_FEAT_C3STOP, 108}; 109EXPORT_SYMBOL(decrementer_clockevent); 110 111/* 112 * This always puts next_tb beyond now, so the clock event will never fire 113 * with the usual comparison, no need for a separate test for stopped. 114 */ 115#define DEC_CLOCKEVENT_STOPPED ~0ULL 116DEFINE_PER_CPU(u64, decrementers_next_tb) = DEC_CLOCKEVENT_STOPPED; 117EXPORT_SYMBOL_GPL(decrementers_next_tb); 118static DEFINE_PER_CPU(struct clock_event_device, decrementers); 119 120#define XSEC_PER_SEC (1024*1024) 121 122#ifdef CONFIG_PPC64 123#define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) 124#else 125/* compute ((xsec << 12) * max) >> 32 */ 126#define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) 127#endif 128 129unsigned long tb_ticks_per_jiffy; 130unsigned long tb_ticks_per_usec = 100; /* sane default */ 131EXPORT_SYMBOL(tb_ticks_per_usec); 132unsigned long tb_ticks_per_sec; 133EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime conversions */ 134 135DEFINE_SPINLOCK(rtc_lock); 136EXPORT_SYMBOL_GPL(rtc_lock); 137 138static u64 tb_to_ns_scale __read_mostly; 139static unsigned tb_to_ns_shift __read_mostly; 140static u64 boot_tb __read_mostly; 141 142extern struct timezone sys_tz; 143static long timezone_offset; 144 145unsigned long ppc_proc_freq; 146EXPORT_SYMBOL_GPL(ppc_proc_freq); 147unsigned long ppc_tb_freq; 148EXPORT_SYMBOL_GPL(ppc_tb_freq); 149 150bool tb_invalid; 151 152#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE 153/* 154 * Read the SPURR on systems that have it, otherwise the PURR, 155 * or if that doesn't exist return the timebase value passed in. 156 */ 157static inline unsigned long read_spurr(unsigned long tb) 158{ 159 if (cpu_has_feature(CPU_FTR_SPURR)) 160 return mfspr(SPRN_SPURR); 161 if (cpu_has_feature(CPU_FTR_PURR)) 162 return mfspr(SPRN_PURR); 163 return tb; 164} 165 166/* 167 * Account time for a transition between system, hard irq 168 * or soft irq state. 169 */ 170static unsigned long vtime_delta_scaled(struct cpu_accounting_data *acct, 171 unsigned long now, unsigned long stime) 172{ 173 unsigned long stime_scaled = 0; 174#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME 175 unsigned long nowscaled, deltascaled; 176 unsigned long utime, utime_scaled; 177 178 nowscaled = read_spurr(now); 179 deltascaled = nowscaled - acct->startspurr; 180 acct->startspurr = nowscaled; 181 utime = acct->utime - acct->utime_sspurr; 182 acct->utime_sspurr = acct->utime; 183 184 /* 185 * Because we don't read the SPURR on every kernel entry/exit, 186 * deltascaled includes both user and system SPURR ticks. 187 * Apportion these ticks to system SPURR ticks and user 188 * SPURR ticks in the same ratio as the system time (delta) 189 * and user time (udelta) values obtained from the timebase 190 * over the same interval. The system ticks get accounted here; 191 * the user ticks get saved up in paca->user_time_scaled to be 192 * used by account_process_tick. 193 */ 194 stime_scaled = stime; 195 utime_scaled = utime; 196 if (deltascaled != stime + utime) { 197 if (utime) { 198 stime_scaled = deltascaled * stime / (stime + utime); 199 utime_scaled = deltascaled - stime_scaled; 200 } else { 201 stime_scaled = deltascaled; 202 } 203 } 204 acct->utime_scaled += utime_scaled; 205#endif 206 207 return stime_scaled; 208} 209 210static unsigned long vtime_delta(struct cpu_accounting_data *acct, 211 unsigned long *stime_scaled, 212 unsigned long *steal_time) 213{ 214 unsigned long now, stime; 215 216 WARN_ON_ONCE(!irqs_disabled()); 217 218 now = mftb(); 219 stime = now - acct->starttime; 220 acct->starttime = now; 221 222 *stime_scaled = vtime_delta_scaled(acct, now, stime); 223 224 if (IS_ENABLED(CONFIG_PPC_SPLPAR) && 225 firmware_has_feature(FW_FEATURE_SPLPAR)) 226 *steal_time = pseries_calculate_stolen_time(now); 227 else 228 *steal_time = 0; 229 230 return stime; 231} 232 233static void vtime_delta_kernel(struct cpu_accounting_data *acct, 234 unsigned long *stime, unsigned long *stime_scaled) 235{ 236 unsigned long steal_time; 237 238 *stime = vtime_delta(acct, stime_scaled, &steal_time); 239 *stime -= min(*stime, steal_time); 240 acct->steal_time += steal_time; 241} 242 243void vtime_account_kernel(struct task_struct *tsk) 244{ 245 struct cpu_accounting_data *acct = get_accounting(tsk); 246 unsigned long stime, stime_scaled; 247 248 vtime_delta_kernel(acct, &stime, &stime_scaled); 249 250 if (tsk->flags & PF_VCPU) { 251 acct->gtime += stime; 252#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME 253 acct->utime_scaled += stime_scaled; 254#endif 255 } else { 256 acct->stime += stime; 257#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME 258 acct->stime_scaled += stime_scaled; 259#endif 260 } 261} 262EXPORT_SYMBOL_GPL(vtime_account_kernel); 263 264void vtime_account_idle(struct task_struct *tsk) 265{ 266 unsigned long stime, stime_scaled, steal_time; 267 struct cpu_accounting_data *acct = get_accounting(tsk); 268 269 stime = vtime_delta(acct, &stime_scaled, &steal_time); 270 acct->idle_time += stime + steal_time; 271} 272 273static void vtime_account_irq_field(struct cpu_accounting_data *acct, 274 unsigned long *field) 275{ 276 unsigned long stime, stime_scaled; 277 278 vtime_delta_kernel(acct, &stime, &stime_scaled); 279 *field += stime; 280#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME 281 acct->stime_scaled += stime_scaled; 282#endif 283} 284 285void vtime_account_softirq(struct task_struct *tsk) 286{ 287 struct cpu_accounting_data *acct = get_accounting(tsk); 288 vtime_account_irq_field(acct, &acct->softirq_time); 289} 290 291void vtime_account_hardirq(struct task_struct *tsk) 292{ 293 struct cpu_accounting_data *acct = get_accounting(tsk); 294 vtime_account_irq_field(acct, &acct->hardirq_time); 295} 296 297static void vtime_flush_scaled(struct task_struct *tsk, 298 struct cpu_accounting_data *acct) 299{ 300#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME 301 if (acct->utime_scaled) 302 tsk->utimescaled += cputime_to_nsecs(acct->utime_scaled); 303 if (acct->stime_scaled) 304 tsk->stimescaled += cputime_to_nsecs(acct->stime_scaled); 305 306 acct->utime_scaled = 0; 307 acct->utime_sspurr = 0; 308 acct->stime_scaled = 0; 309#endif 310} 311 312/* 313 * Account the whole cputime accumulated in the paca 314 * Must be called with interrupts disabled. 315 * Assumes that vtime_account_kernel/idle() has been called 316 * recently (i.e. since the last entry from usermode) so that 317 * get_paca()->user_time_scaled is up to date. 318 */ 319void vtime_flush(struct task_struct *tsk) 320{ 321 struct cpu_accounting_data *acct = get_accounting(tsk); 322 323 if (acct->utime) 324 account_user_time(tsk, cputime_to_nsecs(acct->utime)); 325 326 if (acct->gtime) 327 account_guest_time(tsk, cputime_to_nsecs(acct->gtime)); 328 329 if (IS_ENABLED(CONFIG_PPC_SPLPAR) && acct->steal_time) { 330 account_steal_time(cputime_to_nsecs(acct->steal_time)); 331 acct->steal_time = 0; 332 } 333 334 if (acct->idle_time) 335 account_idle_time(cputime_to_nsecs(acct->idle_time)); 336 337 if (acct->stime) 338 account_system_index_time(tsk, cputime_to_nsecs(acct->stime), 339 CPUTIME_SYSTEM); 340 341 if (acct->hardirq_time) 342 account_system_index_time(tsk, cputime_to_nsecs(acct->hardirq_time), 343 CPUTIME_IRQ); 344 if (acct->softirq_time) 345 account_system_index_time(tsk, cputime_to_nsecs(acct->softirq_time), 346 CPUTIME_SOFTIRQ); 347 348 vtime_flush_scaled(tsk, acct); 349 350 acct->utime = 0; 351 acct->gtime = 0; 352 acct->idle_time = 0; 353 acct->stime = 0; 354 acct->hardirq_time = 0; 355 acct->softirq_time = 0; 356} 357#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ 358 359void __no_kcsan __delay(unsigned long loops) 360{ 361 unsigned long start; 362 363 spin_begin(); 364 if (tb_invalid) { 365 /* 366 * TB is in error state and isn't ticking anymore. 367 * HMI handler was unable to recover from TB error. 368 * Return immediately, so that kernel won't get stuck here. 369 */ 370 spin_cpu_relax(); 371 } else { 372 start = mftb(); 373 while (mftb() - start < loops) 374 spin_cpu_relax(); 375 } 376 spin_end(); 377} 378EXPORT_SYMBOL(__delay); 379 380void __no_kcsan udelay(unsigned long usecs) 381{ 382 __delay(tb_ticks_per_usec * usecs); 383} 384EXPORT_SYMBOL(udelay); 385 386#ifdef CONFIG_SMP 387unsigned long profile_pc(struct pt_regs *regs) 388{ 389 unsigned long pc = instruction_pointer(regs); 390 391 if (in_lock_functions(pc)) 392 return regs->link; 393 394 return pc; 395} 396EXPORT_SYMBOL(profile_pc); 397#endif 398 399#ifdef CONFIG_IRQ_WORK 400 401/* 402 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable... 403 */ 404#ifdef CONFIG_PPC64 405static inline unsigned long test_irq_work_pending(void) 406{ 407 unsigned long x; 408 409 asm volatile("lbz %0,%1(13)" 410 : "=r" (x) 411 : "i" (offsetof(struct paca_struct, irq_work_pending))); 412 return x; 413} 414 415static inline void set_irq_work_pending_flag(void) 416{ 417 asm volatile("stb %0,%1(13)" : : 418 "r" (1), 419 "i" (offsetof(struct paca_struct, irq_work_pending))); 420} 421 422static inline void clear_irq_work_pending(void) 423{ 424 asm volatile("stb %0,%1(13)" : : 425 "r" (0), 426 "i" (offsetof(struct paca_struct, irq_work_pending))); 427} 428 429#else /* 32-bit */ 430 431DEFINE_PER_CPU(u8, irq_work_pending); 432 433#define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1) 434#define test_irq_work_pending() __this_cpu_read(irq_work_pending) 435#define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0) 436 437#endif /* 32 vs 64 bit */ 438 439void arch_irq_work_raise(void) 440{ 441 /* 442 * 64-bit code that uses irq soft-mask can just cause an immediate 443 * interrupt here that gets soft masked, if this is called under 444 * local_irq_disable(). It might be possible to prevent that happening 445 * by noticing interrupts are disabled and setting decrementer pending 446 * to be replayed when irqs are enabled. The problem there is that 447 * tracing can call irq_work_raise, including in code that does low 448 * level manipulations of irq soft-mask state (e.g., trace_hardirqs_on) 449 * which could get tangled up if we're messing with the same state 450 * here. 451 */ 452 preempt_disable(); 453 set_irq_work_pending_flag(); 454 set_dec(1); 455 preempt_enable(); 456} 457 458static void set_dec_or_work(u64 val) 459{ 460 set_dec(val); 461 /* We may have raced with new irq work */ 462 if (unlikely(test_irq_work_pending())) 463 set_dec(1); 464} 465 466#else /* CONFIG_IRQ_WORK */ 467 468#define test_irq_work_pending() 0 469#define clear_irq_work_pending() 470 471static void set_dec_or_work(u64 val) 472{ 473 set_dec(val); 474} 475#endif /* CONFIG_IRQ_WORK */ 476 477#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE 478void timer_rearm_host_dec(u64 now) 479{ 480 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 481 482 WARN_ON_ONCE(!arch_irqs_disabled()); 483 WARN_ON_ONCE(mfmsr() & MSR_EE); 484 485 if (now >= *next_tb) { 486 local_paca->irq_happened |= PACA_IRQ_DEC; 487 } else { 488 now = *next_tb - now; 489 if (now > decrementer_max) 490 now = decrementer_max; 491 set_dec_or_work(now); 492 } 493} 494EXPORT_SYMBOL_GPL(timer_rearm_host_dec); 495#endif 496 497/* 498 * timer_interrupt - gets called when the decrementer overflows, 499 * with interrupts disabled. 500 */ 501DEFINE_INTERRUPT_HANDLER_ASYNC(timer_interrupt) 502{ 503 struct clock_event_device *evt = this_cpu_ptr(&decrementers); 504 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 505 struct pt_regs *old_regs; 506 u64 now; 507 508 /* 509 * Some implementations of hotplug will get timer interrupts while 510 * offline, just ignore these. 511 */ 512 if (unlikely(!cpu_online(smp_processor_id()))) { 513 set_dec(decrementer_max); 514 return; 515 } 516 517 /* Conditionally hard-enable interrupts. */ 518 if (should_hard_irq_enable(regs)) { 519 /* 520 * Ensure a positive value is written to the decrementer, or 521 * else some CPUs will continue to take decrementer exceptions. 522 * When the PPC_WATCHDOG (decrementer based) is configured, 523 * keep this at most 31 bits, which is about 4 seconds on most 524 * systems, which gives the watchdog a chance of catching timer 525 * interrupt hard lockups. 526 */ 527 if (IS_ENABLED(CONFIG_PPC_WATCHDOG)) 528 set_dec(0x7fffffff); 529 else 530 set_dec(decrementer_max); 531 532 do_hard_irq_enable(); 533 } 534 535#if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC) 536 if (atomic_read(&ppc_n_lost_interrupts) != 0) 537 __do_IRQ(regs); 538#endif 539 540 old_regs = set_irq_regs(regs); 541 542 trace_timer_interrupt_entry(regs); 543 544 if (test_irq_work_pending()) { 545 clear_irq_work_pending(); 546 mce_run_irq_context_handlers(); 547 irq_work_run(); 548 } 549 550 now = get_tb(); 551 if (now >= *next_tb) { 552 evt->event_handler(evt); 553 __this_cpu_inc(irq_stat.timer_irqs_event); 554 } else { 555 now = *next_tb - now; 556 if (now > decrementer_max) 557 now = decrementer_max; 558 set_dec_or_work(now); 559 __this_cpu_inc(irq_stat.timer_irqs_others); 560 } 561 562 trace_timer_interrupt_exit(regs); 563 564 set_irq_regs(old_regs); 565} 566EXPORT_SYMBOL(timer_interrupt); 567 568#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST 569void timer_broadcast_interrupt(void) 570{ 571 tick_receive_broadcast(); 572 __this_cpu_inc(irq_stat.broadcast_irqs_event); 573} 574#endif 575 576#ifdef CONFIG_SUSPEND 577/* Overrides the weak version in kernel/power/main.c */ 578void arch_suspend_disable_irqs(void) 579{ 580 if (ppc_md.suspend_disable_irqs) 581 ppc_md.suspend_disable_irqs(); 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/* Overrides the weak version in kernel/power/main.c */ 593void arch_suspend_enable_irqs(void) 594{ 595 local_irq_enable(); 596 597 if (ppc_md.suspend_enable_irqs) 598 ppc_md.suspend_enable_irqs(); 599} 600#endif 601 602unsigned long long tb_to_ns(unsigned long long ticks) 603{ 604 return mulhdu(ticks, tb_to_ns_scale) << tb_to_ns_shift; 605} 606EXPORT_SYMBOL_GPL(tb_to_ns); 607 608/* 609 * Scheduler clock - returns current time in nanosec units. 610 * 611 * Note: mulhdu(a, b) (multiply high double unsigned) returns 612 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 613 * are 64-bit unsigned numbers. 614 */ 615notrace unsigned long long sched_clock(void) 616{ 617 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 618} 619 620 621#ifdef CONFIG_PPC_PSERIES 622 623/* 624 * Running clock - attempts to give a view of time passing for a virtualised 625 * kernels. 626 * Uses the VTB register if available otherwise a next best guess. 627 */ 628unsigned long long running_clock(void) 629{ 630 /* 631 * Don't read the VTB as a host since KVM does not switch in host 632 * timebase into the VTB when it takes a guest off the CPU, reading the 633 * VTB would result in reading 'last switched out' guest VTB. 634 * 635 * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it 636 * would be unsafe to rely only on the #ifdef above. 637 */ 638 if (firmware_has_feature(FW_FEATURE_LPAR) && 639 cpu_has_feature(CPU_FTR_ARCH_207S)) 640 return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 641 642 /* 643 * This is a next best approximation without a VTB. 644 * On a host which is running bare metal there should never be any stolen 645 * time and on a host which doesn't do any virtualisation TB *should* equal 646 * VTB so it makes no difference anyway. 647 */ 648 return local_clock() - kcpustat_this_cpu->cpustat[CPUTIME_STEAL]; 649} 650#endif 651 652static int __init get_freq(char *name, int cells, unsigned long *val) 653{ 654 struct device_node *cpu; 655 const __be32 *fp; 656 int found = 0; 657 658 /* The cpu node should have timebase and clock frequency properties */ 659 cpu = of_find_node_by_type(NULL, "cpu"); 660 661 if (cpu) { 662 fp = of_get_property(cpu, name, NULL); 663 if (fp) { 664 found = 1; 665 *val = of_read_ulong(fp, cells); 666 } 667 668 of_node_put(cpu); 669 } 670 671 return found; 672} 673 674static void start_cpu_decrementer(void) 675{ 676#ifdef CONFIG_BOOKE_OR_40x 677 unsigned int tcr; 678 679 /* Clear any pending timer interrupts */ 680 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 681 682 tcr = mfspr(SPRN_TCR); 683 /* 684 * The watchdog may have already been enabled by u-boot. So leave 685 * TRC[WP] (Watchdog Period) alone. 686 */ 687 tcr &= TCR_WP_MASK; /* Clear all bits except for TCR[WP] */ 688 tcr |= TCR_DIE; /* Enable decrementer */ 689 mtspr(SPRN_TCR, tcr); 690#endif 691} 692 693void __init generic_calibrate_decr(void) 694{ 695 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 696 697 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 698 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 699 700 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 701 "(not found)\n"); 702 } 703 704 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 705 706 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 707 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 708 709 printk(KERN_ERR "WARNING: Estimating processor frequency " 710 "(not found)\n"); 711 } 712} 713 714int update_persistent_clock64(struct timespec64 now) 715{ 716 struct rtc_time tm; 717 718 if (!ppc_md.set_rtc_time) 719 return -ENODEV; 720 721 rtc_time64_to_tm(now.tv_sec + 1 + timezone_offset, &tm); 722 723 return ppc_md.set_rtc_time(&tm); 724} 725 726static void __read_persistent_clock(struct timespec64 *ts) 727{ 728 struct rtc_time tm; 729 static int first = 1; 730 731 ts->tv_nsec = 0; 732 /* XXX this is a little fragile but will work okay in the short term */ 733 if (first) { 734 first = 0; 735 if (ppc_md.time_init) 736 timezone_offset = ppc_md.time_init(); 737 738 /* get_boot_time() isn't guaranteed to be safe to call late */ 739 if (ppc_md.get_boot_time) { 740 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 741 return; 742 } 743 } 744 if (!ppc_md.get_rtc_time) { 745 ts->tv_sec = 0; 746 return; 747 } 748 ppc_md.get_rtc_time(&tm); 749 750 ts->tv_sec = rtc_tm_to_time64(&tm); 751} 752 753void read_persistent_clock64(struct timespec64 *ts) 754{ 755 __read_persistent_clock(ts); 756 757 /* Sanitize it in case real time clock is set below EPOCH */ 758 if (ts->tv_sec < 0) { 759 ts->tv_sec = 0; 760 ts->tv_nsec = 0; 761 } 762 763} 764 765/* clocksource code */ 766static notrace u64 timebase_read(struct clocksource *cs) 767{ 768 return (u64)get_tb(); 769} 770 771static void __init clocksource_init(void) 772{ 773 struct clocksource *clock = &clocksource_timebase; 774 775 if (clocksource_register_hz(clock, tb_ticks_per_sec)) { 776 printk(KERN_ERR "clocksource: %s is already registered\n", 777 clock->name); 778 return; 779 } 780 781 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 782 clock->name, clock->mult, clock->shift); 783} 784 785static int decrementer_set_next_event(unsigned long evt, 786 struct clock_event_device *dev) 787{ 788 __this_cpu_write(decrementers_next_tb, get_tb() + evt); 789 set_dec_or_work(evt); 790 791 return 0; 792} 793 794static int decrementer_shutdown(struct clock_event_device *dev) 795{ 796 __this_cpu_write(decrementers_next_tb, DEC_CLOCKEVENT_STOPPED); 797 set_dec_or_work(decrementer_max); 798 799 return 0; 800} 801 802static void register_decrementer_clockevent(int cpu) 803{ 804 struct clock_event_device *dec = &per_cpu(decrementers, cpu); 805 806 *dec = decrementer_clockevent; 807 dec->cpumask = cpumask_of(cpu); 808 809 clockevents_config_and_register(dec, ppc_tb_freq, 2, decrementer_max); 810 811 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 812 dec->name, dec->mult, dec->shift, cpu); 813 814 /* Set values for KVM, see kvm_emulate_dec() */ 815 decrementer_clockevent.mult = dec->mult; 816 decrementer_clockevent.shift = dec->shift; 817} 818 819static void enable_large_decrementer(void) 820{ 821 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 822 return; 823 824 if (decrementer_max <= DECREMENTER_DEFAULT_MAX) 825 return; 826 827 /* 828 * If we're running as the hypervisor we need to enable the LD manually 829 * otherwise firmware should have done it for us. 830 */ 831 if (cpu_has_feature(CPU_FTR_HVMODE)) 832 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_LD); 833} 834 835static void __init set_decrementer_max(void) 836{ 837 struct device_node *cpu; 838 u32 bits = 32; 839 840 /* Prior to ISAv3 the decrementer is always 32 bit */ 841 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 842 return; 843 844 cpu = of_find_node_by_type(NULL, "cpu"); 845 846 if (of_property_read_u32(cpu, "ibm,dec-bits", &bits) == 0) { 847 if (bits > 64 || bits < 32) { 848 pr_warn("time_init: firmware supplied invalid ibm,dec-bits"); 849 bits = 32; 850 } 851 852 /* calculate the signed maximum given this many bits */ 853 decrementer_max = (1ul << (bits - 1)) - 1; 854 } 855 856 of_node_put(cpu); 857 858 pr_info("time_init: %u bit decrementer (max: %llx)\n", 859 bits, decrementer_max); 860} 861 862static void __init init_decrementer_clockevent(void) 863{ 864 register_decrementer_clockevent(smp_processor_id()); 865} 866 867void secondary_cpu_time_init(void) 868{ 869 /* Enable and test the large decrementer for this cpu */ 870 enable_large_decrementer(); 871 872 /* Start the decrementer on CPUs that have manual control 873 * such as BookE 874 */ 875 start_cpu_decrementer(); 876 877 /* FIME: Should make unrelated change to move snapshot_timebase 878 * call here ! */ 879 register_decrementer_clockevent(smp_processor_id()); 880} 881 882/* This function is only called on the boot processor */ 883void __init time_init(void) 884{ 885 struct div_result res; 886 u64 scale; 887 unsigned shift; 888 889 /* Normal PowerPC with timebase register */ 890 if (ppc_md.calibrate_decr) 891 ppc_md.calibrate_decr(); 892 else 893 generic_calibrate_decr(); 894 895 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 896 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 897 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 898 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 899 900 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 901 tb_ticks_per_sec = ppc_tb_freq; 902 tb_ticks_per_usec = ppc_tb_freq / 1000000; 903 904 /* 905 * Compute scale factor for sched_clock. 906 * The calibrate_decr() function has set tb_ticks_per_sec, 907 * which is the timebase frequency. 908 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 909 * the 128-bit result as a 64.64 fixed-point number. 910 * We then shift that number right until it is less than 1.0, 911 * giving us the scale factor and shift count to use in 912 * sched_clock(). 913 */ 914 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 915 scale = res.result_low; 916 for (shift = 0; res.result_high != 0; ++shift) { 917 scale = (scale >> 1) | (res.result_high << 63); 918 res.result_high >>= 1; 919 } 920 tb_to_ns_scale = scale; 921 tb_to_ns_shift = shift; 922 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 923 boot_tb = get_tb(); 924 925 /* If platform provided a timezone (pmac), we correct the time */ 926 if (timezone_offset) { 927 sys_tz.tz_minuteswest = -timezone_offset / 60; 928 sys_tz.tz_dsttime = 0; 929 } 930 931 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 932 933 /* initialise and enable the large decrementer (if we have one) */ 934 set_decrementer_max(); 935 enable_large_decrementer(); 936 937 /* Start the decrementer on CPUs that have manual control 938 * such as BookE 939 */ 940 start_cpu_decrementer(); 941 942 /* Register the clocksource */ 943 clocksource_init(); 944 945 init_decrementer_clockevent(); 946 tick_setup_hrtimer_broadcast(); 947 948 of_clk_init(NULL); 949 enable_sched_clock_irqtime(); 950} 951 952/* 953 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 954 * result. 955 */ 956void div128_by_32(u64 dividend_high, u64 dividend_low, 957 unsigned divisor, struct div_result *dr) 958{ 959 unsigned long a, b, c, d; 960 unsigned long w, x, y, z; 961 u64 ra, rb, rc; 962 963 a = dividend_high >> 32; 964 b = dividend_high & 0xffffffff; 965 c = dividend_low >> 32; 966 d = dividend_low & 0xffffffff; 967 968 w = a / divisor; 969 ra = ((u64)(a - (w * divisor)) << 32) + b; 970 971 rb = ((u64) do_div(ra, divisor) << 32) + c; 972 x = ra; 973 974 rc = ((u64) do_div(rb, divisor) << 32) + d; 975 y = rb; 976 977 do_div(rc, divisor); 978 z = rc; 979 980 dr->result_high = ((u64)w << 32) + x; 981 dr->result_low = ((u64)y << 32) + z; 982 983} 984 985/* We don't need to calibrate delay, we use the CPU timebase for that */ 986void calibrate_delay(void) 987{ 988 /* Some generic code (such as spinlock debug) use loops_per_jiffy 989 * as the number of __delay(1) in a jiffy, so make it so 990 */ 991 loops_per_jiffy = tb_ticks_per_jiffy; 992} 993 994#if IS_ENABLED(CONFIG_RTC_DRV_GENERIC) 995static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm) 996{ 997 ppc_md.get_rtc_time(tm); 998 return 0; 999} 1000 1001static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm) 1002{ 1003 if (!ppc_md.set_rtc_time) 1004 return -EOPNOTSUPP; 1005 1006 if (ppc_md.set_rtc_time(tm) < 0) 1007 return -EOPNOTSUPP; 1008 1009 return 0; 1010} 1011 1012static const struct rtc_class_ops rtc_generic_ops = { 1013 .read_time = rtc_generic_get_time, 1014 .set_time = rtc_generic_set_time, 1015}; 1016 1017static int __init rtc_init(void) 1018{ 1019 struct platform_device *pdev; 1020 1021 if (!ppc_md.get_rtc_time) 1022 return -ENODEV; 1023 1024 pdev = platform_device_register_data(NULL, "rtc-generic", -1, 1025 &rtc_generic_ops, 1026 sizeof(rtc_generic_ops)); 1027 1028 return PTR_ERR_OR_ZERO(pdev); 1029} 1030 1031device_initcall(rtc_init); 1032#endif 1033