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/sched/clock.h> 38 #include <linux/kernel.h> 39 #include <linux/param.h> 40 #include <linux/string.h> 41 #include <linux/mm.h> 42 #include <linux/interrupt.h> 43 #include <linux/timex.h> 44 #include <linux/kernel_stat.h> 45 #include <linux/time.h> 46 #include <linux/clockchips.h> 47 #include <linux/init.h> 48 #include <linux/profile.h> 49 #include <linux/cpu.h> 50 #include <linux/security.h> 51 #include <linux/percpu.h> 52 #include <linux/rtc.h> 53 #include <linux/jiffies.h> 54 #include <linux/posix-timers.h> 55 #include <linux/irq.h> 56 #include <linux/delay.h> 57 #include <linux/irq_work.h> 58 #include <linux/clk-provider.h> 59 #include <linux/suspend.h> 60 #include <linux/rtc.h> 61 #include <linux/sched/cputime.h> 62 #include <asm/trace.h> 63 64 #include <asm/io.h> 65 #include <asm/processor.h> 66 #include <asm/nvram.h> 67 #include <asm/cache.h> 68 #include <asm/machdep.h> 69 #include <linux/uaccess.h> 70 #include <asm/time.h> 71 #include <asm/prom.h> 72 #include <asm/irq.h> 73 #include <asm/div64.h> 74 #include <asm/smp.h> 75 #include <asm/vdso_datapage.h> 76 #include <asm/firmware.h> 77 #include <asm/asm-prototypes.h> 78 79 /* powerpc clocksource/clockevent code */ 80 81 #include <linux/clockchips.h> 82 #include <linux/timekeeper_internal.h> 83 84 static u64 rtc_read(struct clocksource *); 85 static struct clocksource clocksource_rtc = { 86 .name = "rtc", 87 .rating = 400, 88 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 89 .mask = CLOCKSOURCE_MASK(64), 90 .read = rtc_read, 91 }; 92 93 static u64 timebase_read(struct clocksource *); 94 static struct clocksource clocksource_timebase = { 95 .name = "timebase", 96 .rating = 400, 97 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 98 .mask = CLOCKSOURCE_MASK(64), 99 .read = timebase_read, 100 }; 101 102 #define DECREMENTER_DEFAULT_MAX 0x7FFFFFFF 103 u64 decrementer_max = DECREMENTER_DEFAULT_MAX; 104 105 static int decrementer_set_next_event(unsigned long evt, 106 struct clock_event_device *dev); 107 static int decrementer_shutdown(struct clock_event_device *evt); 108 109 struct clock_event_device decrementer_clockevent = { 110 .name = "decrementer", 111 .rating = 200, 112 .irq = 0, 113 .set_next_event = decrementer_set_next_event, 114 .set_state_shutdown = decrementer_shutdown, 115 .tick_resume = decrementer_shutdown, 116 .features = CLOCK_EVT_FEAT_ONESHOT | 117 CLOCK_EVT_FEAT_C3STOP, 118 }; 119 EXPORT_SYMBOL(decrementer_clockevent); 120 121 DEFINE_PER_CPU(u64, decrementers_next_tb); 122 static DEFINE_PER_CPU(struct clock_event_device, decrementers); 123 124 #define XSEC_PER_SEC (1024*1024) 125 126 #ifdef CONFIG_PPC64 127 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) 128 #else 129 /* compute ((xsec << 12) * max) >> 32 */ 130 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) 131 #endif 132 133 unsigned long tb_ticks_per_jiffy; 134 unsigned long tb_ticks_per_usec = 100; /* sane default */ 135 EXPORT_SYMBOL(tb_ticks_per_usec); 136 unsigned long tb_ticks_per_sec; 137 EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ 138 139 DEFINE_SPINLOCK(rtc_lock); 140 EXPORT_SYMBOL_GPL(rtc_lock); 141 142 static u64 tb_to_ns_scale __read_mostly; 143 static unsigned tb_to_ns_shift __read_mostly; 144 static u64 boot_tb __read_mostly; 145 146 extern struct timezone sys_tz; 147 static long timezone_offset; 148 149 unsigned long ppc_proc_freq; 150 EXPORT_SYMBOL_GPL(ppc_proc_freq); 151 unsigned long ppc_tb_freq; 152 EXPORT_SYMBOL_GPL(ppc_tb_freq); 153 154 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE 155 /* 156 * Factor for converting from cputime_t (timebase ticks) to 157 * microseconds. This is stored as 0.64 fixed-point binary fraction. 158 */ 159 u64 __cputime_usec_factor; 160 EXPORT_SYMBOL(__cputime_usec_factor); 161 162 #ifdef CONFIG_PPC_SPLPAR 163 void (*dtl_consumer)(struct dtl_entry *, u64); 164 #endif 165 166 #ifdef CONFIG_PPC64 167 #define get_accounting(tsk) (&get_paca()->accounting) 168 #else 169 #define get_accounting(tsk) (&task_thread_info(tsk)->accounting) 170 #endif 171 172 static void calc_cputime_factors(void) 173 { 174 struct div_result res; 175 176 div128_by_32(1000000, 0, tb_ticks_per_sec, &res); 177 __cputime_usec_factor = res.result_low; 178 } 179 180 /* 181 * Read the SPURR on systems that have it, otherwise the PURR, 182 * or if that doesn't exist return the timebase value passed in. 183 */ 184 static unsigned long read_spurr(unsigned long tb) 185 { 186 if (cpu_has_feature(CPU_FTR_SPURR)) 187 return mfspr(SPRN_SPURR); 188 if (cpu_has_feature(CPU_FTR_PURR)) 189 return mfspr(SPRN_PURR); 190 return tb; 191 } 192 193 #ifdef CONFIG_PPC_SPLPAR 194 195 /* 196 * Scan the dispatch trace log and count up the stolen time. 197 * Should be called with interrupts disabled. 198 */ 199 static u64 scan_dispatch_log(u64 stop_tb) 200 { 201 u64 i = local_paca->dtl_ridx; 202 struct dtl_entry *dtl = local_paca->dtl_curr; 203 struct dtl_entry *dtl_end = local_paca->dispatch_log_end; 204 struct lppaca *vpa = local_paca->lppaca_ptr; 205 u64 tb_delta; 206 u64 stolen = 0; 207 u64 dtb; 208 209 if (!dtl) 210 return 0; 211 212 if (i == be64_to_cpu(vpa->dtl_idx)) 213 return 0; 214 while (i < be64_to_cpu(vpa->dtl_idx)) { 215 dtb = be64_to_cpu(dtl->timebase); 216 tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) + 217 be32_to_cpu(dtl->ready_to_enqueue_time); 218 barrier(); 219 if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) { 220 /* buffer has overflowed */ 221 i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG; 222 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG); 223 continue; 224 } 225 if (dtb > stop_tb) 226 break; 227 if (dtl_consumer) 228 dtl_consumer(dtl, i); 229 stolen += tb_delta; 230 ++i; 231 ++dtl; 232 if (dtl == dtl_end) 233 dtl = local_paca->dispatch_log; 234 } 235 local_paca->dtl_ridx = i; 236 local_paca->dtl_curr = dtl; 237 return stolen; 238 } 239 240 /* 241 * Accumulate stolen time by scanning the dispatch trace log. 242 * Called on entry from user mode. 243 */ 244 void accumulate_stolen_time(void) 245 { 246 u64 sst, ust; 247 u8 save_soft_enabled = local_paca->soft_enabled; 248 struct cpu_accounting_data *acct = &local_paca->accounting; 249 250 /* We are called early in the exception entry, before 251 * soft/hard_enabled are sync'ed to the expected state 252 * for the exception. We are hard disabled but the PACA 253 * needs to reflect that so various debug stuff doesn't 254 * complain 255 */ 256 local_paca->soft_enabled = 0; 257 258 sst = scan_dispatch_log(acct->starttime_user); 259 ust = scan_dispatch_log(acct->starttime); 260 acct->stime -= sst; 261 acct->utime -= ust; 262 acct->steal_time += ust + sst; 263 264 local_paca->soft_enabled = save_soft_enabled; 265 } 266 267 static inline u64 calculate_stolen_time(u64 stop_tb) 268 { 269 if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx)) 270 return scan_dispatch_log(stop_tb); 271 272 return 0; 273 } 274 275 #else /* CONFIG_PPC_SPLPAR */ 276 static inline u64 calculate_stolen_time(u64 stop_tb) 277 { 278 return 0; 279 } 280 281 #endif /* CONFIG_PPC_SPLPAR */ 282 283 /* 284 * Account time for a transition between system, hard irq 285 * or soft irq state. 286 */ 287 static unsigned long vtime_delta(struct task_struct *tsk, 288 unsigned long *stime_scaled, 289 unsigned long *steal_time) 290 { 291 unsigned long now, nowscaled, deltascaled; 292 unsigned long stime; 293 unsigned long utime, utime_scaled; 294 struct cpu_accounting_data *acct = get_accounting(tsk); 295 296 WARN_ON_ONCE(!irqs_disabled()); 297 298 now = mftb(); 299 nowscaled = read_spurr(now); 300 stime = now - acct->starttime; 301 acct->starttime = now; 302 deltascaled = nowscaled - acct->startspurr; 303 acct->startspurr = nowscaled; 304 305 *steal_time = calculate_stolen_time(now); 306 307 utime = acct->utime - acct->utime_sspurr; 308 acct->utime_sspurr = acct->utime; 309 310 /* 311 * Because we don't read the SPURR on every kernel entry/exit, 312 * deltascaled includes both user and system SPURR ticks. 313 * Apportion these ticks to system SPURR ticks and user 314 * SPURR ticks in the same ratio as the system time (delta) 315 * and user time (udelta) values obtained from the timebase 316 * over the same interval. The system ticks get accounted here; 317 * the user ticks get saved up in paca->user_time_scaled to be 318 * used by account_process_tick. 319 */ 320 *stime_scaled = stime; 321 utime_scaled = utime; 322 if (deltascaled != stime + utime) { 323 if (utime) { 324 *stime_scaled = deltascaled * stime / (stime + utime); 325 utime_scaled = deltascaled - *stime_scaled; 326 } else { 327 *stime_scaled = deltascaled; 328 } 329 } 330 acct->utime_scaled += utime_scaled; 331 332 return stime; 333 } 334 335 void vtime_account_system(struct task_struct *tsk) 336 { 337 unsigned long stime, stime_scaled, steal_time; 338 struct cpu_accounting_data *acct = get_accounting(tsk); 339 340 stime = vtime_delta(tsk, &stime_scaled, &steal_time); 341 342 stime -= min(stime, steal_time); 343 acct->steal_time += steal_time; 344 345 if ((tsk->flags & PF_VCPU) && !irq_count()) { 346 acct->gtime += stime; 347 acct->utime_scaled += stime_scaled; 348 } else { 349 if (hardirq_count()) 350 acct->hardirq_time += stime; 351 else if (in_serving_softirq()) 352 acct->softirq_time += stime; 353 else 354 acct->stime += stime; 355 356 acct->stime_scaled += stime_scaled; 357 } 358 } 359 EXPORT_SYMBOL_GPL(vtime_account_system); 360 361 void vtime_account_idle(struct task_struct *tsk) 362 { 363 unsigned long stime, stime_scaled, steal_time; 364 struct cpu_accounting_data *acct = get_accounting(tsk); 365 366 stime = vtime_delta(tsk, &stime_scaled, &steal_time); 367 acct->idle_time += stime + steal_time; 368 } 369 370 /* 371 * Account the whole cputime accumulated in the paca 372 * Must be called with interrupts disabled. 373 * Assumes that vtime_account_system/idle() has been called 374 * recently (i.e. since the last entry from usermode) so that 375 * get_paca()->user_time_scaled is up to date. 376 */ 377 void vtime_flush(struct task_struct *tsk) 378 { 379 struct cpu_accounting_data *acct = get_accounting(tsk); 380 381 if (acct->utime) 382 account_user_time(tsk, cputime_to_nsecs(acct->utime)); 383 384 if (acct->utime_scaled) 385 tsk->utimescaled += cputime_to_nsecs(acct->utime_scaled); 386 387 if (acct->gtime) 388 account_guest_time(tsk, cputime_to_nsecs(acct->gtime)); 389 390 if (acct->steal_time) 391 account_steal_time(cputime_to_nsecs(acct->steal_time)); 392 393 if (acct->idle_time) 394 account_idle_time(cputime_to_nsecs(acct->idle_time)); 395 396 if (acct->stime) 397 account_system_index_time(tsk, cputime_to_nsecs(acct->stime), 398 CPUTIME_SYSTEM); 399 if (acct->stime_scaled) 400 tsk->stimescaled += cputime_to_nsecs(acct->stime_scaled); 401 402 if (acct->hardirq_time) 403 account_system_index_time(tsk, cputime_to_nsecs(acct->hardirq_time), 404 CPUTIME_IRQ); 405 if (acct->softirq_time) 406 account_system_index_time(tsk, cputime_to_nsecs(acct->softirq_time), 407 CPUTIME_SOFTIRQ); 408 409 acct->utime = 0; 410 acct->utime_scaled = 0; 411 acct->utime_sspurr = 0; 412 acct->gtime = 0; 413 acct->steal_time = 0; 414 acct->idle_time = 0; 415 acct->stime = 0; 416 acct->stime_scaled = 0; 417 acct->hardirq_time = 0; 418 acct->softirq_time = 0; 419 } 420 421 #ifdef CONFIG_PPC32 422 /* 423 * Called from the context switch with interrupts disabled, to charge all 424 * accumulated times to the current process, and to prepare accounting on 425 * the next process. 426 */ 427 void arch_vtime_task_switch(struct task_struct *prev) 428 { 429 struct cpu_accounting_data *acct = get_accounting(current); 430 431 acct->starttime = get_accounting(prev)->starttime; 432 acct->startspurr = get_accounting(prev)->startspurr; 433 } 434 #endif /* CONFIG_PPC32 */ 435 436 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ 437 #define calc_cputime_factors() 438 #endif 439 440 void __delay(unsigned long loops) 441 { 442 unsigned long start; 443 int diff; 444 445 if (__USE_RTC()) { 446 start = get_rtcl(); 447 do { 448 /* the RTCL register wraps at 1000000000 */ 449 diff = get_rtcl() - start; 450 if (diff < 0) 451 diff += 1000000000; 452 } while (diff < loops); 453 } else { 454 start = get_tbl(); 455 while (get_tbl() - start < loops) 456 HMT_low(); 457 HMT_medium(); 458 } 459 } 460 EXPORT_SYMBOL(__delay); 461 462 void udelay(unsigned long usecs) 463 { 464 __delay(tb_ticks_per_usec * usecs); 465 } 466 EXPORT_SYMBOL(udelay); 467 468 #ifdef CONFIG_SMP 469 unsigned long profile_pc(struct pt_regs *regs) 470 { 471 unsigned long pc = instruction_pointer(regs); 472 473 if (in_lock_functions(pc)) 474 return regs->link; 475 476 return pc; 477 } 478 EXPORT_SYMBOL(profile_pc); 479 #endif 480 481 #ifdef CONFIG_IRQ_WORK 482 483 /* 484 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable... 485 */ 486 #ifdef CONFIG_PPC64 487 static inline unsigned long test_irq_work_pending(void) 488 { 489 unsigned long x; 490 491 asm volatile("lbz %0,%1(13)" 492 : "=r" (x) 493 : "i" (offsetof(struct paca_struct, irq_work_pending))); 494 return x; 495 } 496 497 static inline void set_irq_work_pending_flag(void) 498 { 499 asm volatile("stb %0,%1(13)" : : 500 "r" (1), 501 "i" (offsetof(struct paca_struct, irq_work_pending))); 502 } 503 504 static inline void clear_irq_work_pending(void) 505 { 506 asm volatile("stb %0,%1(13)" : : 507 "r" (0), 508 "i" (offsetof(struct paca_struct, irq_work_pending))); 509 } 510 511 #else /* 32-bit */ 512 513 DEFINE_PER_CPU(u8, irq_work_pending); 514 515 #define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1) 516 #define test_irq_work_pending() __this_cpu_read(irq_work_pending) 517 #define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0) 518 519 #endif /* 32 vs 64 bit */ 520 521 void arch_irq_work_raise(void) 522 { 523 preempt_disable(); 524 set_irq_work_pending_flag(); 525 set_dec(1); 526 preempt_enable(); 527 } 528 529 #else /* CONFIG_IRQ_WORK */ 530 531 #define test_irq_work_pending() 0 532 #define clear_irq_work_pending() 533 534 #endif /* CONFIG_IRQ_WORK */ 535 536 static void __timer_interrupt(void) 537 { 538 struct pt_regs *regs = get_irq_regs(); 539 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 540 struct clock_event_device *evt = this_cpu_ptr(&decrementers); 541 u64 now; 542 543 trace_timer_interrupt_entry(regs); 544 545 if (test_irq_work_pending()) { 546 clear_irq_work_pending(); 547 irq_work_run(); 548 } 549 550 now = get_tb_or_rtc(); 551 if (now >= *next_tb) { 552 *next_tb = ~(u64)0; 553 if (evt->event_handler) 554 evt->event_handler(evt); 555 __this_cpu_inc(irq_stat.timer_irqs_event); 556 } else { 557 now = *next_tb - now; 558 if (now <= decrementer_max) 559 set_dec(now); 560 /* We may have raced with new irq work */ 561 if (test_irq_work_pending()) 562 set_dec(1); 563 __this_cpu_inc(irq_stat.timer_irqs_others); 564 } 565 566 #ifdef CONFIG_PPC64 567 /* collect purr register values often, for accurate calculations */ 568 if (firmware_has_feature(FW_FEATURE_SPLPAR)) { 569 struct cpu_usage *cu = this_cpu_ptr(&cpu_usage_array); 570 cu->current_tb = mfspr(SPRN_PURR); 571 } 572 #endif 573 574 trace_timer_interrupt_exit(regs); 575 } 576 577 /* 578 * timer_interrupt - gets called when the decrementer overflows, 579 * with interrupts disabled. 580 */ 581 void timer_interrupt(struct pt_regs * regs) 582 { 583 struct pt_regs *old_regs; 584 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 585 586 /* Ensure a positive value is written to the decrementer, or else 587 * some CPUs will continue to take decrementer exceptions. 588 */ 589 set_dec(decrementer_max); 590 591 /* Some implementations of hotplug will get timer interrupts while 592 * offline, just ignore these and we also need to set 593 * decrementers_next_tb as MAX to make sure __check_irq_replay 594 * don't replay timer interrupt when return, otherwise we'll trap 595 * here infinitely :( 596 */ 597 if (!cpu_online(smp_processor_id())) { 598 *next_tb = ~(u64)0; 599 return; 600 } 601 602 /* Conditionally hard-enable interrupts now that the DEC has been 603 * bumped to its maximum value 604 */ 605 may_hard_irq_enable(); 606 607 608 #if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC) 609 if (atomic_read(&ppc_n_lost_interrupts) != 0) 610 do_IRQ(regs); 611 #endif 612 613 old_regs = set_irq_regs(regs); 614 irq_enter(); 615 616 __timer_interrupt(); 617 irq_exit(); 618 set_irq_regs(old_regs); 619 } 620 EXPORT_SYMBOL(timer_interrupt); 621 622 /* 623 * Hypervisor decrementer interrupts shouldn't occur but are sometimes 624 * left pending on exit from a KVM guest. We don't need to do anything 625 * to clear them, as they are edge-triggered. 626 */ 627 void hdec_interrupt(struct pt_regs *regs) 628 { 629 } 630 631 #ifdef CONFIG_SUSPEND 632 static void generic_suspend_disable_irqs(void) 633 { 634 /* Disable the decrementer, so that it doesn't interfere 635 * with suspending. 636 */ 637 638 set_dec(decrementer_max); 639 local_irq_disable(); 640 set_dec(decrementer_max); 641 } 642 643 static void generic_suspend_enable_irqs(void) 644 { 645 local_irq_enable(); 646 } 647 648 /* Overrides the weak version in kernel/power/main.c */ 649 void arch_suspend_disable_irqs(void) 650 { 651 if (ppc_md.suspend_disable_irqs) 652 ppc_md.suspend_disable_irqs(); 653 generic_suspend_disable_irqs(); 654 } 655 656 /* Overrides the weak version in kernel/power/main.c */ 657 void arch_suspend_enable_irqs(void) 658 { 659 generic_suspend_enable_irqs(); 660 if (ppc_md.suspend_enable_irqs) 661 ppc_md.suspend_enable_irqs(); 662 } 663 #endif 664 665 unsigned long long tb_to_ns(unsigned long long ticks) 666 { 667 return mulhdu(ticks, tb_to_ns_scale) << tb_to_ns_shift; 668 } 669 EXPORT_SYMBOL_GPL(tb_to_ns); 670 671 /* 672 * Scheduler clock - returns current time in nanosec units. 673 * 674 * Note: mulhdu(a, b) (multiply high double unsigned) returns 675 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 676 * are 64-bit unsigned numbers. 677 */ 678 unsigned long long sched_clock(void) 679 { 680 if (__USE_RTC()) 681 return get_rtc(); 682 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 683 } 684 685 686 #ifdef CONFIG_PPC_PSERIES 687 688 /* 689 * Running clock - attempts to give a view of time passing for a virtualised 690 * kernels. 691 * Uses the VTB register if available otherwise a next best guess. 692 */ 693 unsigned long long running_clock(void) 694 { 695 /* 696 * Don't read the VTB as a host since KVM does not switch in host 697 * timebase into the VTB when it takes a guest off the CPU, reading the 698 * VTB would result in reading 'last switched out' guest VTB. 699 * 700 * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it 701 * would be unsafe to rely only on the #ifdef above. 702 */ 703 if (firmware_has_feature(FW_FEATURE_LPAR) && 704 cpu_has_feature(CPU_FTR_ARCH_207S)) 705 return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 706 707 /* 708 * This is a next best approximation without a VTB. 709 * On a host which is running bare metal there should never be any stolen 710 * time and on a host which doesn't do any virtualisation TB *should* equal 711 * VTB so it makes no difference anyway. 712 */ 713 return local_clock() - kcpustat_this_cpu->cpustat[CPUTIME_STEAL]; 714 } 715 #endif 716 717 static int __init get_freq(char *name, int cells, unsigned long *val) 718 { 719 struct device_node *cpu; 720 const __be32 *fp; 721 int found = 0; 722 723 /* The cpu node should have timebase and clock frequency properties */ 724 cpu = of_find_node_by_type(NULL, "cpu"); 725 726 if (cpu) { 727 fp = of_get_property(cpu, name, NULL); 728 if (fp) { 729 found = 1; 730 *val = of_read_ulong(fp, cells); 731 } 732 733 of_node_put(cpu); 734 } 735 736 return found; 737 } 738 739 static void start_cpu_decrementer(void) 740 { 741 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) 742 /* Clear any pending timer interrupts */ 743 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 744 745 /* Enable decrementer interrupt */ 746 mtspr(SPRN_TCR, TCR_DIE); 747 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */ 748 } 749 750 void __init generic_calibrate_decr(void) 751 { 752 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 753 754 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 755 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 756 757 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 758 "(not found)\n"); 759 } 760 761 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 762 763 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 764 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 765 766 printk(KERN_ERR "WARNING: Estimating processor frequency " 767 "(not found)\n"); 768 } 769 } 770 771 int update_persistent_clock(struct timespec now) 772 { 773 struct rtc_time tm; 774 775 if (!ppc_md.set_rtc_time) 776 return -ENODEV; 777 778 to_tm(now.tv_sec + 1 + timezone_offset, &tm); 779 tm.tm_year -= 1900; 780 tm.tm_mon -= 1; 781 782 return ppc_md.set_rtc_time(&tm); 783 } 784 785 static void __read_persistent_clock(struct timespec *ts) 786 { 787 struct rtc_time tm; 788 static int first = 1; 789 790 ts->tv_nsec = 0; 791 /* XXX this is a litle fragile but will work okay in the short term */ 792 if (first) { 793 first = 0; 794 if (ppc_md.time_init) 795 timezone_offset = ppc_md.time_init(); 796 797 /* get_boot_time() isn't guaranteed to be safe to call late */ 798 if (ppc_md.get_boot_time) { 799 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 800 return; 801 } 802 } 803 if (!ppc_md.get_rtc_time) { 804 ts->tv_sec = 0; 805 return; 806 } 807 ppc_md.get_rtc_time(&tm); 808 809 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, 810 tm.tm_hour, tm.tm_min, tm.tm_sec); 811 } 812 813 void read_persistent_clock(struct timespec *ts) 814 { 815 __read_persistent_clock(ts); 816 817 /* Sanitize it in case real time clock is set below EPOCH */ 818 if (ts->tv_sec < 0) { 819 ts->tv_sec = 0; 820 ts->tv_nsec = 0; 821 } 822 823 } 824 825 /* clocksource code */ 826 static u64 rtc_read(struct clocksource *cs) 827 { 828 return (u64)get_rtc(); 829 } 830 831 static u64 timebase_read(struct clocksource *cs) 832 { 833 return (u64)get_tb(); 834 } 835 836 void update_vsyscall_old(struct timespec *wall_time, struct timespec *wtm, 837 struct clocksource *clock, u32 mult, u64 cycle_last) 838 { 839 u64 new_tb_to_xs, new_stamp_xsec; 840 u32 frac_sec; 841 842 if (clock != &clocksource_timebase) 843 return; 844 845 /* Make userspace gettimeofday spin until we're done. */ 846 ++vdso_data->tb_update_count; 847 smp_mb(); 848 849 /* 19342813113834067 ~= 2^(20+64) / 1e9 */ 850 new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift); 851 new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC; 852 do_div(new_stamp_xsec, 1000000000); 853 new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC; 854 855 BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC); 856 /* this is tv_nsec / 1e9 as a 0.32 fraction */ 857 frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32; 858 859 /* 860 * tb_update_count is used to allow the userspace gettimeofday code 861 * to assure itself that it sees a consistent view of the tb_to_xs and 862 * stamp_xsec variables. It reads the tb_update_count, then reads 863 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If 864 * the two values of tb_update_count match and are even then the 865 * tb_to_xs and stamp_xsec values are consistent. If not, then it 866 * loops back and reads them again until this criteria is met. 867 * We expect the caller to have done the first increment of 868 * vdso_data->tb_update_count already. 869 */ 870 vdso_data->tb_orig_stamp = cycle_last; 871 vdso_data->stamp_xsec = new_stamp_xsec; 872 vdso_data->tb_to_xs = new_tb_to_xs; 873 vdso_data->wtom_clock_sec = wtm->tv_sec; 874 vdso_data->wtom_clock_nsec = wtm->tv_nsec; 875 vdso_data->stamp_xtime = *wall_time; 876 vdso_data->stamp_sec_fraction = frac_sec; 877 smp_wmb(); 878 ++(vdso_data->tb_update_count); 879 } 880 881 void update_vsyscall_tz(void) 882 { 883 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; 884 vdso_data->tz_dsttime = sys_tz.tz_dsttime; 885 } 886 887 static void __init clocksource_init(void) 888 { 889 struct clocksource *clock; 890 891 if (__USE_RTC()) 892 clock = &clocksource_rtc; 893 else 894 clock = &clocksource_timebase; 895 896 if (clocksource_register_hz(clock, tb_ticks_per_sec)) { 897 printk(KERN_ERR "clocksource: %s is already registered\n", 898 clock->name); 899 return; 900 } 901 902 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 903 clock->name, clock->mult, clock->shift); 904 } 905 906 static int decrementer_set_next_event(unsigned long evt, 907 struct clock_event_device *dev) 908 { 909 __this_cpu_write(decrementers_next_tb, get_tb_or_rtc() + evt); 910 set_dec(evt); 911 912 /* We may have raced with new irq work */ 913 if (test_irq_work_pending()) 914 set_dec(1); 915 916 return 0; 917 } 918 919 static int decrementer_shutdown(struct clock_event_device *dev) 920 { 921 decrementer_set_next_event(decrementer_max, dev); 922 return 0; 923 } 924 925 /* Interrupt handler for the timer broadcast IPI */ 926 void tick_broadcast_ipi_handler(void) 927 { 928 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 929 930 *next_tb = get_tb_or_rtc(); 931 __timer_interrupt(); 932 } 933 934 static void register_decrementer_clockevent(int cpu) 935 { 936 struct clock_event_device *dec = &per_cpu(decrementers, cpu); 937 938 *dec = decrementer_clockevent; 939 dec->cpumask = cpumask_of(cpu); 940 941 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 942 dec->name, dec->mult, dec->shift, cpu); 943 944 clockevents_register_device(dec); 945 } 946 947 static void enable_large_decrementer(void) 948 { 949 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 950 return; 951 952 if (decrementer_max <= DECREMENTER_DEFAULT_MAX) 953 return; 954 955 /* 956 * If we're running as the hypervisor we need to enable the LD manually 957 * otherwise firmware should have done it for us. 958 */ 959 if (cpu_has_feature(CPU_FTR_HVMODE)) 960 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_LD); 961 } 962 963 static void __init set_decrementer_max(void) 964 { 965 struct device_node *cpu; 966 u32 bits = 32; 967 968 /* Prior to ISAv3 the decrementer is always 32 bit */ 969 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 970 return; 971 972 cpu = of_find_node_by_type(NULL, "cpu"); 973 974 if (of_property_read_u32(cpu, "ibm,dec-bits", &bits) == 0) { 975 if (bits > 64 || bits < 32) { 976 pr_warn("time_init: firmware supplied invalid ibm,dec-bits"); 977 bits = 32; 978 } 979 980 /* calculate the signed maximum given this many bits */ 981 decrementer_max = (1ul << (bits - 1)) - 1; 982 } 983 984 of_node_put(cpu); 985 986 pr_info("time_init: %u bit decrementer (max: %llx)\n", 987 bits, decrementer_max); 988 } 989 990 static void __init init_decrementer_clockevent(void) 991 { 992 int cpu = smp_processor_id(); 993 994 clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4); 995 996 decrementer_clockevent.max_delta_ns = 997 clockevent_delta2ns(decrementer_max, &decrementer_clockevent); 998 decrementer_clockevent.min_delta_ns = 999 clockevent_delta2ns(2, &decrementer_clockevent); 1000 1001 register_decrementer_clockevent(cpu); 1002 } 1003 1004 void secondary_cpu_time_init(void) 1005 { 1006 /* Enable and test the large decrementer for this cpu */ 1007 enable_large_decrementer(); 1008 1009 /* Start the decrementer on CPUs that have manual control 1010 * such as BookE 1011 */ 1012 start_cpu_decrementer(); 1013 1014 /* FIME: Should make unrelatred change to move snapshot_timebase 1015 * call here ! */ 1016 register_decrementer_clockevent(smp_processor_id()); 1017 } 1018 1019 /* This function is only called on the boot processor */ 1020 void __init time_init(void) 1021 { 1022 struct div_result res; 1023 u64 scale; 1024 unsigned shift; 1025 1026 if (__USE_RTC()) { 1027 /* 601 processor: dec counts down by 128 every 128ns */ 1028 ppc_tb_freq = 1000000000; 1029 } else { 1030 /* Normal PowerPC with timebase register */ 1031 ppc_md.calibrate_decr(); 1032 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 1033 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 1034 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 1035 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 1036 } 1037 1038 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 1039 tb_ticks_per_sec = ppc_tb_freq; 1040 tb_ticks_per_usec = ppc_tb_freq / 1000000; 1041 calc_cputime_factors(); 1042 1043 /* 1044 * Compute scale factor for sched_clock. 1045 * The calibrate_decr() function has set tb_ticks_per_sec, 1046 * which is the timebase frequency. 1047 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 1048 * the 128-bit result as a 64.64 fixed-point number. 1049 * We then shift that number right until it is less than 1.0, 1050 * giving us the scale factor and shift count to use in 1051 * sched_clock(). 1052 */ 1053 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 1054 scale = res.result_low; 1055 for (shift = 0; res.result_high != 0; ++shift) { 1056 scale = (scale >> 1) | (res.result_high << 63); 1057 res.result_high >>= 1; 1058 } 1059 tb_to_ns_scale = scale; 1060 tb_to_ns_shift = shift; 1061 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 1062 boot_tb = get_tb_or_rtc(); 1063 1064 /* If platform provided a timezone (pmac), we correct the time */ 1065 if (timezone_offset) { 1066 sys_tz.tz_minuteswest = -timezone_offset / 60; 1067 sys_tz.tz_dsttime = 0; 1068 } 1069 1070 vdso_data->tb_update_count = 0; 1071 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 1072 1073 /* initialise and enable the large decrementer (if we have one) */ 1074 set_decrementer_max(); 1075 enable_large_decrementer(); 1076 1077 /* Start the decrementer on CPUs that have manual control 1078 * such as BookE 1079 */ 1080 start_cpu_decrementer(); 1081 1082 /* Register the clocksource */ 1083 clocksource_init(); 1084 1085 init_decrementer_clockevent(); 1086 tick_setup_hrtimer_broadcast(); 1087 1088 #ifdef CONFIG_COMMON_CLK 1089 of_clk_init(NULL); 1090 #endif 1091 } 1092 1093 1094 #define FEBRUARY 2 1095 #define STARTOFTIME 1970 1096 #define SECDAY 86400L 1097 #define SECYR (SECDAY * 365) 1098 #define leapyear(year) ((year) % 4 == 0 && \ 1099 ((year) % 100 != 0 || (year) % 400 == 0)) 1100 #define days_in_year(a) (leapyear(a) ? 366 : 365) 1101 #define days_in_month(a) (month_days[(a) - 1]) 1102 1103 static int month_days[12] = { 1104 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 1105 }; 1106 1107 void to_tm(int tim, struct rtc_time * tm) 1108 { 1109 register int i; 1110 register long hms, day; 1111 1112 day = tim / SECDAY; 1113 hms = tim % SECDAY; 1114 1115 /* Hours, minutes, seconds are easy */ 1116 tm->tm_hour = hms / 3600; 1117 tm->tm_min = (hms % 3600) / 60; 1118 tm->tm_sec = (hms % 3600) % 60; 1119 1120 /* Number of years in days */ 1121 for (i = STARTOFTIME; day >= days_in_year(i); i++) 1122 day -= days_in_year(i); 1123 tm->tm_year = i; 1124 1125 /* Number of months in days left */ 1126 if (leapyear(tm->tm_year)) 1127 days_in_month(FEBRUARY) = 29; 1128 for (i = 1; day >= days_in_month(i); i++) 1129 day -= days_in_month(i); 1130 days_in_month(FEBRUARY) = 28; 1131 tm->tm_mon = i; 1132 1133 /* Days are what is left over (+1) from all that. */ 1134 tm->tm_mday = day + 1; 1135 1136 /* 1137 * No-one uses the day of the week. 1138 */ 1139 tm->tm_wday = -1; 1140 } 1141 EXPORT_SYMBOL(to_tm); 1142 1143 /* 1144 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 1145 * result. 1146 */ 1147 void div128_by_32(u64 dividend_high, u64 dividend_low, 1148 unsigned divisor, struct div_result *dr) 1149 { 1150 unsigned long a, b, c, d; 1151 unsigned long w, x, y, z; 1152 u64 ra, rb, rc; 1153 1154 a = dividend_high >> 32; 1155 b = dividend_high & 0xffffffff; 1156 c = dividend_low >> 32; 1157 d = dividend_low & 0xffffffff; 1158 1159 w = a / divisor; 1160 ra = ((u64)(a - (w * divisor)) << 32) + b; 1161 1162 rb = ((u64) do_div(ra, divisor) << 32) + c; 1163 x = ra; 1164 1165 rc = ((u64) do_div(rb, divisor) << 32) + d; 1166 y = rb; 1167 1168 do_div(rc, divisor); 1169 z = rc; 1170 1171 dr->result_high = ((u64)w << 32) + x; 1172 dr->result_low = ((u64)y << 32) + z; 1173 1174 } 1175 1176 /* We don't need to calibrate delay, we use the CPU timebase for that */ 1177 void calibrate_delay(void) 1178 { 1179 /* Some generic code (such as spinlock debug) use loops_per_jiffy 1180 * as the number of __delay(1) in a jiffy, so make it so 1181 */ 1182 loops_per_jiffy = tb_ticks_per_jiffy; 1183 } 1184 1185 #if IS_ENABLED(CONFIG_RTC_DRV_GENERIC) 1186 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm) 1187 { 1188 ppc_md.get_rtc_time(tm); 1189 return rtc_valid_tm(tm); 1190 } 1191 1192 static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm) 1193 { 1194 if (!ppc_md.set_rtc_time) 1195 return -EOPNOTSUPP; 1196 1197 if (ppc_md.set_rtc_time(tm) < 0) 1198 return -EOPNOTSUPP; 1199 1200 return 0; 1201 } 1202 1203 static const struct rtc_class_ops rtc_generic_ops = { 1204 .read_time = rtc_generic_get_time, 1205 .set_time = rtc_generic_set_time, 1206 }; 1207 1208 static int __init rtc_init(void) 1209 { 1210 struct platform_device *pdev; 1211 1212 if (!ppc_md.get_rtc_time) 1213 return -ENODEV; 1214 1215 pdev = platform_device_register_data(NULL, "rtc-generic", -1, 1216 &rtc_generic_ops, 1217 sizeof(rtc_generic_ops)); 1218 1219 return PTR_ERR_OR_ZERO(pdev); 1220 } 1221 1222 device_initcall(rtc_init); 1223 #endif 1224