1 /* 2 * Common time routines among all ppc machines. 3 * 4 * Written by Cort Dougan (cort@cs.nmt.edu) to merge 5 * Paul Mackerras' version and mine for PReP and Pmac. 6 * MPC8xx/MBX changes by Dan Malek (dmalek@jlc.net). 7 * Converted for 64-bit by Mike Corrigan (mikejc@us.ibm.com) 8 * 9 * First round of bugfixes by Gabriel Paubert (paubert@iram.es) 10 * to make clock more stable (2.4.0-test5). The only thing 11 * that this code assumes is that the timebases have been synchronized 12 * by firmware on SMP and are never stopped (never do sleep 13 * on SMP then, nap and doze are OK). 14 * 15 * Speeded up do_gettimeofday by getting rid of references to 16 * xtime (which required locks for consistency). (mikejc@us.ibm.com) 17 * 18 * TODO (not necessarily in this file): 19 * - improve precision and reproducibility of timebase frequency 20 * measurement at boot time. 21 * - for astronomical applications: add a new function to get 22 * non ambiguous timestamps even around leap seconds. This needs 23 * a new timestamp format and a good name. 24 * 25 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 26 * "A Kernel Model for Precision Timekeeping" by Dave Mills 27 * 28 * This program is free software; you can redistribute it and/or 29 * modify it under the terms of the GNU General Public License 30 * as published by the Free Software Foundation; either version 31 * 2 of the License, or (at your option) any later version. 32 */ 33 34 #include <linux/errno.h> 35 #include <linux/export.h> 36 #include <linux/sched.h> 37 #include <linux/kernel.h> 38 #include <linux/param.h> 39 #include <linux/string.h> 40 #include <linux/mm.h> 41 #include <linux/interrupt.h> 42 #include <linux/timex.h> 43 #include <linux/kernel_stat.h> 44 #include <linux/time.h> 45 #include <linux/clockchips.h> 46 #include <linux/init.h> 47 #include <linux/profile.h> 48 #include <linux/cpu.h> 49 #include <linux/security.h> 50 #include <linux/percpu.h> 51 #include <linux/rtc.h> 52 #include <linux/jiffies.h> 53 #include <linux/posix-timers.h> 54 #include <linux/irq.h> 55 #include <linux/delay.h> 56 #include <linux/irq_work.h> 57 #include <linux/clk-provider.h> 58 #include <linux/suspend.h> 59 #include <linux/rtc.h> 60 #include <asm/trace.h> 61 62 #include <asm/io.h> 63 #include <asm/processor.h> 64 #include <asm/nvram.h> 65 #include <asm/cache.h> 66 #include <asm/machdep.h> 67 #include <asm/uaccess.h> 68 #include <asm/time.h> 69 #include <asm/prom.h> 70 #include <asm/irq.h> 71 #include <asm/div64.h> 72 #include <asm/smp.h> 73 #include <asm/vdso_datapage.h> 74 #include <asm/firmware.h> 75 #include <asm/cputime.h> 76 77 /* powerpc clocksource/clockevent code */ 78 79 #include <linux/clockchips.h> 80 #include <linux/timekeeper_internal.h> 81 82 static cycle_t rtc_read(struct clocksource *); 83 static struct clocksource clocksource_rtc = { 84 .name = "rtc", 85 .rating = 400, 86 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 87 .mask = CLOCKSOURCE_MASK(64), 88 .read = rtc_read, 89 }; 90 91 static cycle_t timebase_read(struct clocksource *); 92 static struct clocksource clocksource_timebase = { 93 .name = "timebase", 94 .rating = 400, 95 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 96 .mask = CLOCKSOURCE_MASK(64), 97 .read = timebase_read, 98 }; 99 100 #define DECREMENTER_DEFAULT_MAX 0x7FFFFFFF 101 u64 decrementer_max = DECREMENTER_DEFAULT_MAX; 102 103 static int decrementer_set_next_event(unsigned long evt, 104 struct clock_event_device *dev); 105 static int decrementer_shutdown(struct clock_event_device *evt); 106 107 struct clock_event_device decrementer_clockevent = { 108 .name = "decrementer", 109 .rating = 200, 110 .irq = 0, 111 .set_next_event = decrementer_set_next_event, 112 .set_state_shutdown = decrementer_shutdown, 113 .tick_resume = decrementer_shutdown, 114 .features = CLOCK_EVT_FEAT_ONESHOT | 115 CLOCK_EVT_FEAT_C3STOP, 116 }; 117 EXPORT_SYMBOL(decrementer_clockevent); 118 119 DEFINE_PER_CPU(u64, decrementers_next_tb); 120 static DEFINE_PER_CPU(struct clock_event_device, decrementers); 121 122 #define XSEC_PER_SEC (1024*1024) 123 124 #ifdef CONFIG_PPC64 125 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) 126 #else 127 /* compute ((xsec << 12) * max) >> 32 */ 128 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) 129 #endif 130 131 unsigned long tb_ticks_per_jiffy; 132 unsigned long tb_ticks_per_usec = 100; /* sane default */ 133 EXPORT_SYMBOL(tb_ticks_per_usec); 134 unsigned long tb_ticks_per_sec; 135 EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ 136 137 DEFINE_SPINLOCK(rtc_lock); 138 EXPORT_SYMBOL_GPL(rtc_lock); 139 140 static u64 tb_to_ns_scale __read_mostly; 141 static unsigned tb_to_ns_shift __read_mostly; 142 static u64 boot_tb __read_mostly; 143 144 extern struct timezone sys_tz; 145 static long timezone_offset; 146 147 unsigned long ppc_proc_freq; 148 EXPORT_SYMBOL_GPL(ppc_proc_freq); 149 unsigned long ppc_tb_freq; 150 EXPORT_SYMBOL_GPL(ppc_tb_freq); 151 152 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE 153 /* 154 * Factors for converting from cputime_t (timebase ticks) to 155 * jiffies, microseconds, seconds, and clock_t (1/USER_HZ seconds). 156 * These are all stored as 0.64 fixed-point binary fractions. 157 */ 158 u64 __cputime_jiffies_factor; 159 EXPORT_SYMBOL(__cputime_jiffies_factor); 160 u64 __cputime_usec_factor; 161 EXPORT_SYMBOL(__cputime_usec_factor); 162 u64 __cputime_sec_factor; 163 EXPORT_SYMBOL(__cputime_sec_factor); 164 u64 __cputime_clockt_factor; 165 EXPORT_SYMBOL(__cputime_clockt_factor); 166 DEFINE_PER_CPU(unsigned long, cputime_last_delta); 167 DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta); 168 169 cputime_t cputime_one_jiffy; 170 171 #ifdef CONFIG_PPC_SPLPAR 172 void (*dtl_consumer)(struct dtl_entry *, u64); 173 #endif 174 175 #ifdef CONFIG_PPC64 176 #define get_accounting(tsk) (&get_paca()->accounting) 177 #else 178 #define get_accounting(tsk) (&task_thread_info(tsk)->accounting) 179 #endif 180 181 static void calc_cputime_factors(void) 182 { 183 struct div_result res; 184 185 div128_by_32(HZ, 0, tb_ticks_per_sec, &res); 186 __cputime_jiffies_factor = res.result_low; 187 div128_by_32(1000000, 0, tb_ticks_per_sec, &res); 188 __cputime_usec_factor = res.result_low; 189 div128_by_32(1, 0, tb_ticks_per_sec, &res); 190 __cputime_sec_factor = res.result_low; 191 div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res); 192 __cputime_clockt_factor = res.result_low; 193 } 194 195 /* 196 * Read the SPURR on systems that have it, otherwise the PURR, 197 * or if that doesn't exist return the timebase value passed in. 198 */ 199 static unsigned long read_spurr(unsigned long tb) 200 { 201 if (cpu_has_feature(CPU_FTR_SPURR)) 202 return mfspr(SPRN_SPURR); 203 if (cpu_has_feature(CPU_FTR_PURR)) 204 return mfspr(SPRN_PURR); 205 return tb; 206 } 207 208 #ifdef CONFIG_PPC_SPLPAR 209 210 /* 211 * Scan the dispatch trace log and count up the stolen time. 212 * Should be called with interrupts disabled. 213 */ 214 static u64 scan_dispatch_log(u64 stop_tb) 215 { 216 u64 i = local_paca->dtl_ridx; 217 struct dtl_entry *dtl = local_paca->dtl_curr; 218 struct dtl_entry *dtl_end = local_paca->dispatch_log_end; 219 struct lppaca *vpa = local_paca->lppaca_ptr; 220 u64 tb_delta; 221 u64 stolen = 0; 222 u64 dtb; 223 224 if (!dtl) 225 return 0; 226 227 if (i == be64_to_cpu(vpa->dtl_idx)) 228 return 0; 229 while (i < be64_to_cpu(vpa->dtl_idx)) { 230 dtb = be64_to_cpu(dtl->timebase); 231 tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) + 232 be32_to_cpu(dtl->ready_to_enqueue_time); 233 barrier(); 234 if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) { 235 /* buffer has overflowed */ 236 i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG; 237 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG); 238 continue; 239 } 240 if (dtb > stop_tb) 241 break; 242 if (dtl_consumer) 243 dtl_consumer(dtl, i); 244 stolen += tb_delta; 245 ++i; 246 ++dtl; 247 if (dtl == dtl_end) 248 dtl = local_paca->dispatch_log; 249 } 250 local_paca->dtl_ridx = i; 251 local_paca->dtl_curr = dtl; 252 return stolen; 253 } 254 255 /* 256 * Accumulate stolen time by scanning the dispatch trace log. 257 * Called on entry from user mode. 258 */ 259 void accumulate_stolen_time(void) 260 { 261 u64 sst, ust; 262 u8 save_soft_enabled = local_paca->soft_enabled; 263 struct cpu_accounting_data *acct = &local_paca->accounting; 264 265 /* We are called early in the exception entry, before 266 * soft/hard_enabled are sync'ed to the expected state 267 * for the exception. We are hard disabled but the PACA 268 * needs to reflect that so various debug stuff doesn't 269 * complain 270 */ 271 local_paca->soft_enabled = 0; 272 273 sst = scan_dispatch_log(acct->starttime_user); 274 ust = scan_dispatch_log(acct->starttime); 275 acct->system_time -= sst; 276 acct->user_time -= ust; 277 local_paca->stolen_time += ust + sst; 278 279 local_paca->soft_enabled = save_soft_enabled; 280 } 281 282 static inline u64 calculate_stolen_time(u64 stop_tb) 283 { 284 u64 stolen = 0; 285 286 if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx)) { 287 stolen = scan_dispatch_log(stop_tb); 288 get_paca()->accounting.system_time -= stolen; 289 } 290 291 stolen += get_paca()->stolen_time; 292 get_paca()->stolen_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->system_time += 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->system_time; 328 acct->system_time = 0; 329 udelta = acct->user_time - acct->utime_sspurr; 330 acct->utime_sspurr = acct->user_time; 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->user_time_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, sys_scaled); 363 if (stolen) 364 account_steal_time(stolen); 365 } 366 EXPORT_SYMBOL_GPL(vtime_account_system); 367 368 void vtime_account_idle(struct task_struct *tsk) 369 { 370 unsigned long delta, sys_scaled, stolen; 371 372 delta = vtime_delta(tsk, &sys_scaled, &stolen); 373 account_idle_time(delta + stolen); 374 } 375 376 /* 377 * Transfer the user time accumulated in the paca 378 * by the exception entry and exit code to the generic 379 * process user time records. 380 * Must be called with interrupts disabled. 381 * Assumes that vtime_account_system/idle() has been called 382 * recently (i.e. since the last entry from usermode) so that 383 * get_paca()->user_time_scaled is up to date. 384 */ 385 void vtime_account_user(struct task_struct *tsk) 386 { 387 cputime_t utime, utimescaled; 388 struct cpu_accounting_data *acct = get_accounting(tsk); 389 390 utime = acct->user_time; 391 utimescaled = acct->user_time_scaled; 392 acct->user_time = 0; 393 acct->user_time_scaled = 0; 394 acct->utime_sspurr = 0; 395 account_user_time(tsk, utime, utimescaled); 396 } 397 398 #ifdef CONFIG_PPC32 399 /* 400 * Called from the context switch with interrupts disabled, to charge all 401 * accumulated times to the current process, and to prepare accounting on 402 * the next process. 403 */ 404 void arch_vtime_task_switch(struct task_struct *prev) 405 { 406 struct cpu_accounting_data *acct = get_accounting(current); 407 408 acct->starttime = get_accounting(prev)->starttime; 409 acct->system_time = 0; 410 acct->user_time = 0; 411 } 412 #endif /* CONFIG_PPC32 */ 413 414 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ 415 #define calc_cputime_factors() 416 #endif 417 418 void __delay(unsigned long loops) 419 { 420 unsigned long start; 421 int diff; 422 423 if (__USE_RTC()) { 424 start = get_rtcl(); 425 do { 426 /* the RTCL register wraps at 1000000000 */ 427 diff = get_rtcl() - start; 428 if (diff < 0) 429 diff += 1000000000; 430 } while (diff < loops); 431 } else { 432 start = get_tbl(); 433 while (get_tbl() - start < loops) 434 HMT_low(); 435 HMT_medium(); 436 } 437 } 438 EXPORT_SYMBOL(__delay); 439 440 void udelay(unsigned long usecs) 441 { 442 __delay(tb_ticks_per_usec * usecs); 443 } 444 EXPORT_SYMBOL(udelay); 445 446 #ifdef CONFIG_SMP 447 unsigned long profile_pc(struct pt_regs *regs) 448 { 449 unsigned long pc = instruction_pointer(regs); 450 451 if (in_lock_functions(pc)) 452 return regs->link; 453 454 return pc; 455 } 456 EXPORT_SYMBOL(profile_pc); 457 #endif 458 459 #ifdef CONFIG_IRQ_WORK 460 461 /* 462 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable... 463 */ 464 #ifdef CONFIG_PPC64 465 static inline unsigned long test_irq_work_pending(void) 466 { 467 unsigned long x; 468 469 asm volatile("lbz %0,%1(13)" 470 : "=r" (x) 471 : "i" (offsetof(struct paca_struct, irq_work_pending))); 472 return x; 473 } 474 475 static inline void set_irq_work_pending_flag(void) 476 { 477 asm volatile("stb %0,%1(13)" : : 478 "r" (1), 479 "i" (offsetof(struct paca_struct, irq_work_pending))); 480 } 481 482 static inline void clear_irq_work_pending(void) 483 { 484 asm volatile("stb %0,%1(13)" : : 485 "r" (0), 486 "i" (offsetof(struct paca_struct, irq_work_pending))); 487 } 488 489 #else /* 32-bit */ 490 491 DEFINE_PER_CPU(u8, irq_work_pending); 492 493 #define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1) 494 #define test_irq_work_pending() __this_cpu_read(irq_work_pending) 495 #define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0) 496 497 #endif /* 32 vs 64 bit */ 498 499 void arch_irq_work_raise(void) 500 { 501 preempt_disable(); 502 set_irq_work_pending_flag(); 503 set_dec(1); 504 preempt_enable(); 505 } 506 507 #else /* CONFIG_IRQ_WORK */ 508 509 #define test_irq_work_pending() 0 510 #define clear_irq_work_pending() 511 512 #endif /* CONFIG_IRQ_WORK */ 513 514 static void __timer_interrupt(void) 515 { 516 struct pt_regs *regs = get_irq_regs(); 517 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 518 struct clock_event_device *evt = this_cpu_ptr(&decrementers); 519 u64 now; 520 521 trace_timer_interrupt_entry(regs); 522 523 if (test_irq_work_pending()) { 524 clear_irq_work_pending(); 525 irq_work_run(); 526 } 527 528 now = get_tb_or_rtc(); 529 if (now >= *next_tb) { 530 *next_tb = ~(u64)0; 531 if (evt->event_handler) 532 evt->event_handler(evt); 533 __this_cpu_inc(irq_stat.timer_irqs_event); 534 } else { 535 now = *next_tb - now; 536 if (now <= decrementer_max) 537 set_dec(now); 538 /* We may have raced with new irq work */ 539 if (test_irq_work_pending()) 540 set_dec(1); 541 __this_cpu_inc(irq_stat.timer_irqs_others); 542 } 543 544 #ifdef CONFIG_PPC64 545 /* collect purr register values often, for accurate calculations */ 546 if (firmware_has_feature(FW_FEATURE_SPLPAR)) { 547 struct cpu_usage *cu = this_cpu_ptr(&cpu_usage_array); 548 cu->current_tb = mfspr(SPRN_PURR); 549 } 550 #endif 551 552 trace_timer_interrupt_exit(regs); 553 } 554 555 /* 556 * timer_interrupt - gets called when the decrementer overflows, 557 * with interrupts disabled. 558 */ 559 void timer_interrupt(struct pt_regs * regs) 560 { 561 struct pt_regs *old_regs; 562 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 563 564 /* Ensure a positive value is written to the decrementer, or else 565 * some CPUs will continue to take decrementer exceptions. 566 */ 567 set_dec(decrementer_max); 568 569 /* Some implementations of hotplug will get timer interrupts while 570 * offline, just ignore these and we also need to set 571 * decrementers_next_tb as MAX to make sure __check_irq_replay 572 * don't replay timer interrupt when return, otherwise we'll trap 573 * here infinitely :( 574 */ 575 if (!cpu_online(smp_processor_id())) { 576 *next_tb = ~(u64)0; 577 return; 578 } 579 580 /* Conditionally hard-enable interrupts now that the DEC has been 581 * bumped to its maximum value 582 */ 583 may_hard_irq_enable(); 584 585 586 #if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC) 587 if (atomic_read(&ppc_n_lost_interrupts) != 0) 588 do_IRQ(regs); 589 #endif 590 591 old_regs = set_irq_regs(regs); 592 irq_enter(); 593 594 __timer_interrupt(); 595 irq_exit(); 596 set_irq_regs(old_regs); 597 } 598 EXPORT_SYMBOL(timer_interrupt); 599 600 /* 601 * Hypervisor decrementer interrupts shouldn't occur but are sometimes 602 * left pending on exit from a KVM guest. We don't need to do anything 603 * to clear them, as they are edge-triggered. 604 */ 605 void hdec_interrupt(struct pt_regs *regs) 606 { 607 } 608 609 #ifdef CONFIG_SUSPEND 610 static void generic_suspend_disable_irqs(void) 611 { 612 /* Disable the decrementer, so that it doesn't interfere 613 * with suspending. 614 */ 615 616 set_dec(decrementer_max); 617 local_irq_disable(); 618 set_dec(decrementer_max); 619 } 620 621 static void generic_suspend_enable_irqs(void) 622 { 623 local_irq_enable(); 624 } 625 626 /* Overrides the weak version in kernel/power/main.c */ 627 void arch_suspend_disable_irqs(void) 628 { 629 if (ppc_md.suspend_disable_irqs) 630 ppc_md.suspend_disable_irqs(); 631 generic_suspend_disable_irqs(); 632 } 633 634 /* Overrides the weak version in kernel/power/main.c */ 635 void arch_suspend_enable_irqs(void) 636 { 637 generic_suspend_enable_irqs(); 638 if (ppc_md.suspend_enable_irqs) 639 ppc_md.suspend_enable_irqs(); 640 } 641 #endif 642 643 unsigned long long tb_to_ns(unsigned long long ticks) 644 { 645 return mulhdu(ticks, tb_to_ns_scale) << tb_to_ns_shift; 646 } 647 EXPORT_SYMBOL_GPL(tb_to_ns); 648 649 /* 650 * Scheduler clock - returns current time in nanosec units. 651 * 652 * Note: mulhdu(a, b) (multiply high double unsigned) returns 653 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 654 * are 64-bit unsigned numbers. 655 */ 656 unsigned long long sched_clock(void) 657 { 658 if (__USE_RTC()) 659 return get_rtc(); 660 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 661 } 662 663 664 #ifdef CONFIG_PPC_PSERIES 665 666 /* 667 * Running clock - attempts to give a view of time passing for a virtualised 668 * kernels. 669 * Uses the VTB register if available otherwise a next best guess. 670 */ 671 unsigned long long running_clock(void) 672 { 673 /* 674 * Don't read the VTB as a host since KVM does not switch in host 675 * timebase into the VTB when it takes a guest off the CPU, reading the 676 * VTB would result in reading 'last switched out' guest VTB. 677 * 678 * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it 679 * would be unsafe to rely only on the #ifdef above. 680 */ 681 if (firmware_has_feature(FW_FEATURE_LPAR) && 682 cpu_has_feature(CPU_FTR_ARCH_207S)) 683 return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 684 685 /* 686 * This is a next best approximation without a VTB. 687 * On a host which is running bare metal there should never be any stolen 688 * time and on a host which doesn't do any virtualisation TB *should* equal 689 * VTB so it makes no difference anyway. 690 */ 691 return local_clock() - cputime_to_nsecs(kcpustat_this_cpu->cpustat[CPUTIME_STEAL]); 692 } 693 #endif 694 695 static int __init get_freq(char *name, int cells, unsigned long *val) 696 { 697 struct device_node *cpu; 698 const __be32 *fp; 699 int found = 0; 700 701 /* The cpu node should have timebase and clock frequency properties */ 702 cpu = of_find_node_by_type(NULL, "cpu"); 703 704 if (cpu) { 705 fp = of_get_property(cpu, name, NULL); 706 if (fp) { 707 found = 1; 708 *val = of_read_ulong(fp, cells); 709 } 710 711 of_node_put(cpu); 712 } 713 714 return found; 715 } 716 717 static void start_cpu_decrementer(void) 718 { 719 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) 720 /* Clear any pending timer interrupts */ 721 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 722 723 /* Enable decrementer interrupt */ 724 mtspr(SPRN_TCR, TCR_DIE); 725 #endif /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */ 726 } 727 728 void __init generic_calibrate_decr(void) 729 { 730 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 731 732 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 733 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 734 735 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 736 "(not found)\n"); 737 } 738 739 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 740 741 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 742 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 743 744 printk(KERN_ERR "WARNING: Estimating processor frequency " 745 "(not found)\n"); 746 } 747 } 748 749 int update_persistent_clock(struct timespec now) 750 { 751 struct rtc_time tm; 752 753 if (!ppc_md.set_rtc_time) 754 return -ENODEV; 755 756 to_tm(now.tv_sec + 1 + timezone_offset, &tm); 757 tm.tm_year -= 1900; 758 tm.tm_mon -= 1; 759 760 return ppc_md.set_rtc_time(&tm); 761 } 762 763 static void __read_persistent_clock(struct timespec *ts) 764 { 765 struct rtc_time tm; 766 static int first = 1; 767 768 ts->tv_nsec = 0; 769 /* XXX this is a litle fragile but will work okay in the short term */ 770 if (first) { 771 first = 0; 772 if (ppc_md.time_init) 773 timezone_offset = ppc_md.time_init(); 774 775 /* get_boot_time() isn't guaranteed to be safe to call late */ 776 if (ppc_md.get_boot_time) { 777 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 778 return; 779 } 780 } 781 if (!ppc_md.get_rtc_time) { 782 ts->tv_sec = 0; 783 return; 784 } 785 ppc_md.get_rtc_time(&tm); 786 787 ts->tv_sec = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, 788 tm.tm_hour, tm.tm_min, tm.tm_sec); 789 } 790 791 void read_persistent_clock(struct timespec *ts) 792 { 793 __read_persistent_clock(ts); 794 795 /* Sanitize it in case real time clock is set below EPOCH */ 796 if (ts->tv_sec < 0) { 797 ts->tv_sec = 0; 798 ts->tv_nsec = 0; 799 } 800 801 } 802 803 /* clocksource code */ 804 static cycle_t rtc_read(struct clocksource *cs) 805 { 806 return (cycle_t)get_rtc(); 807 } 808 809 static cycle_t timebase_read(struct clocksource *cs) 810 { 811 return (cycle_t)get_tb(); 812 } 813 814 void update_vsyscall_old(struct timespec *wall_time, struct timespec *wtm, 815 struct clocksource *clock, u32 mult, cycle_t cycle_last) 816 { 817 u64 new_tb_to_xs, new_stamp_xsec; 818 u32 frac_sec; 819 820 if (clock != &clocksource_timebase) 821 return; 822 823 /* Make userspace gettimeofday spin until we're done. */ 824 ++vdso_data->tb_update_count; 825 smp_mb(); 826 827 /* 19342813113834067 ~= 2^(20+64) / 1e9 */ 828 new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift); 829 new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC; 830 do_div(new_stamp_xsec, 1000000000); 831 new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC; 832 833 BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC); 834 /* this is tv_nsec / 1e9 as a 0.32 fraction */ 835 frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32; 836 837 /* 838 * tb_update_count is used to allow the userspace gettimeofday code 839 * to assure itself that it sees a consistent view of the tb_to_xs and 840 * stamp_xsec variables. It reads the tb_update_count, then reads 841 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If 842 * the two values of tb_update_count match and are even then the 843 * tb_to_xs and stamp_xsec values are consistent. If not, then it 844 * loops back and reads them again until this criteria is met. 845 * We expect the caller to have done the first increment of 846 * vdso_data->tb_update_count already. 847 */ 848 vdso_data->tb_orig_stamp = cycle_last; 849 vdso_data->stamp_xsec = new_stamp_xsec; 850 vdso_data->tb_to_xs = new_tb_to_xs; 851 vdso_data->wtom_clock_sec = wtm->tv_sec; 852 vdso_data->wtom_clock_nsec = wtm->tv_nsec; 853 vdso_data->stamp_xtime = *wall_time; 854 vdso_data->stamp_sec_fraction = frac_sec; 855 smp_wmb(); 856 ++(vdso_data->tb_update_count); 857 } 858 859 void update_vsyscall_tz(void) 860 { 861 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; 862 vdso_data->tz_dsttime = sys_tz.tz_dsttime; 863 } 864 865 static void __init clocksource_init(void) 866 { 867 struct clocksource *clock; 868 869 if (__USE_RTC()) 870 clock = &clocksource_rtc; 871 else 872 clock = &clocksource_timebase; 873 874 if (clocksource_register_hz(clock, tb_ticks_per_sec)) { 875 printk(KERN_ERR "clocksource: %s is already registered\n", 876 clock->name); 877 return; 878 } 879 880 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 881 clock->name, clock->mult, clock->shift); 882 } 883 884 static int decrementer_set_next_event(unsigned long evt, 885 struct clock_event_device *dev) 886 { 887 __this_cpu_write(decrementers_next_tb, get_tb_or_rtc() + evt); 888 set_dec(evt); 889 890 /* We may have raced with new irq work */ 891 if (test_irq_work_pending()) 892 set_dec(1); 893 894 return 0; 895 } 896 897 static int decrementer_shutdown(struct clock_event_device *dev) 898 { 899 decrementer_set_next_event(decrementer_max, dev); 900 return 0; 901 } 902 903 /* Interrupt handler for the timer broadcast IPI */ 904 void tick_broadcast_ipi_handler(void) 905 { 906 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 907 908 *next_tb = get_tb_or_rtc(); 909 __timer_interrupt(); 910 } 911 912 static void register_decrementer_clockevent(int cpu) 913 { 914 struct clock_event_device *dec = &per_cpu(decrementers, cpu); 915 916 *dec = decrementer_clockevent; 917 dec->cpumask = cpumask_of(cpu); 918 919 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 920 dec->name, dec->mult, dec->shift, cpu); 921 922 clockevents_register_device(dec); 923 } 924 925 static void enable_large_decrementer(void) 926 { 927 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 928 return; 929 930 if (decrementer_max <= DECREMENTER_DEFAULT_MAX) 931 return; 932 933 /* 934 * If we're running as the hypervisor we need to enable the LD manually 935 * otherwise firmware should have done it for us. 936 */ 937 if (cpu_has_feature(CPU_FTR_HVMODE)) 938 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_LD); 939 } 940 941 static void __init set_decrementer_max(void) 942 { 943 struct device_node *cpu; 944 u32 bits = 32; 945 946 /* Prior to ISAv3 the decrementer is always 32 bit */ 947 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 948 return; 949 950 cpu = of_find_node_by_type(NULL, "cpu"); 951 952 if (of_property_read_u32(cpu, "ibm,dec-bits", &bits) == 0) { 953 if (bits > 64 || bits < 32) { 954 pr_warn("time_init: firmware supplied invalid ibm,dec-bits"); 955 bits = 32; 956 } 957 958 /* calculate the signed maximum given this many bits */ 959 decrementer_max = (1ul << (bits - 1)) - 1; 960 } 961 962 of_node_put(cpu); 963 964 pr_info("time_init: %u bit decrementer (max: %llx)\n", 965 bits, decrementer_max); 966 } 967 968 static void __init init_decrementer_clockevent(void) 969 { 970 int cpu = smp_processor_id(); 971 972 clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4); 973 974 decrementer_clockevent.max_delta_ns = 975 clockevent_delta2ns(decrementer_max, &decrementer_clockevent); 976 decrementer_clockevent.min_delta_ns = 977 clockevent_delta2ns(2, &decrementer_clockevent); 978 979 register_decrementer_clockevent(cpu); 980 } 981 982 void secondary_cpu_time_init(void) 983 { 984 /* Enable and test the large decrementer for this cpu */ 985 enable_large_decrementer(); 986 987 /* Start the decrementer on CPUs that have manual control 988 * such as BookE 989 */ 990 start_cpu_decrementer(); 991 992 /* FIME: Should make unrelatred change to move snapshot_timebase 993 * call here ! */ 994 register_decrementer_clockevent(smp_processor_id()); 995 } 996 997 /* This function is only called on the boot processor */ 998 void __init time_init(void) 999 { 1000 struct div_result res; 1001 u64 scale; 1002 unsigned shift; 1003 1004 if (__USE_RTC()) { 1005 /* 601 processor: dec counts down by 128 every 128ns */ 1006 ppc_tb_freq = 1000000000; 1007 } else { 1008 /* Normal PowerPC with timebase register */ 1009 ppc_md.calibrate_decr(); 1010 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 1011 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 1012 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 1013 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 1014 } 1015 1016 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 1017 tb_ticks_per_sec = ppc_tb_freq; 1018 tb_ticks_per_usec = ppc_tb_freq / 1000000; 1019 calc_cputime_factors(); 1020 setup_cputime_one_jiffy(); 1021 1022 /* 1023 * Compute scale factor for sched_clock. 1024 * The calibrate_decr() function has set tb_ticks_per_sec, 1025 * which is the timebase frequency. 1026 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 1027 * the 128-bit result as a 64.64 fixed-point number. 1028 * We then shift that number right until it is less than 1.0, 1029 * giving us the scale factor and shift count to use in 1030 * sched_clock(). 1031 */ 1032 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 1033 scale = res.result_low; 1034 for (shift = 0; res.result_high != 0; ++shift) { 1035 scale = (scale >> 1) | (res.result_high << 63); 1036 res.result_high >>= 1; 1037 } 1038 tb_to_ns_scale = scale; 1039 tb_to_ns_shift = shift; 1040 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 1041 boot_tb = get_tb_or_rtc(); 1042 1043 /* If platform provided a timezone (pmac), we correct the time */ 1044 if (timezone_offset) { 1045 sys_tz.tz_minuteswest = -timezone_offset / 60; 1046 sys_tz.tz_dsttime = 0; 1047 } 1048 1049 vdso_data->tb_update_count = 0; 1050 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 1051 1052 /* initialise and enable the large decrementer (if we have one) */ 1053 set_decrementer_max(); 1054 enable_large_decrementer(); 1055 1056 /* Start the decrementer on CPUs that have manual control 1057 * such as BookE 1058 */ 1059 start_cpu_decrementer(); 1060 1061 /* Register the clocksource */ 1062 clocksource_init(); 1063 1064 init_decrementer_clockevent(); 1065 tick_setup_hrtimer_broadcast(); 1066 1067 #ifdef CONFIG_COMMON_CLK 1068 of_clk_init(NULL); 1069 #endif 1070 } 1071 1072 1073 #define FEBRUARY 2 1074 #define STARTOFTIME 1970 1075 #define SECDAY 86400L 1076 #define SECYR (SECDAY * 365) 1077 #define leapyear(year) ((year) % 4 == 0 && \ 1078 ((year) % 100 != 0 || (year) % 400 == 0)) 1079 #define days_in_year(a) (leapyear(a) ? 366 : 365) 1080 #define days_in_month(a) (month_days[(a) - 1]) 1081 1082 static int month_days[12] = { 1083 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 1084 }; 1085 1086 void to_tm(int tim, struct rtc_time * tm) 1087 { 1088 register int i; 1089 register long hms, day; 1090 1091 day = tim / SECDAY; 1092 hms = tim % SECDAY; 1093 1094 /* Hours, minutes, seconds are easy */ 1095 tm->tm_hour = hms / 3600; 1096 tm->tm_min = (hms % 3600) / 60; 1097 tm->tm_sec = (hms % 3600) % 60; 1098 1099 /* Number of years in days */ 1100 for (i = STARTOFTIME; day >= days_in_year(i); i++) 1101 day -= days_in_year(i); 1102 tm->tm_year = i; 1103 1104 /* Number of months in days left */ 1105 if (leapyear(tm->tm_year)) 1106 days_in_month(FEBRUARY) = 29; 1107 for (i = 1; day >= days_in_month(i); i++) 1108 day -= days_in_month(i); 1109 days_in_month(FEBRUARY) = 28; 1110 tm->tm_mon = i; 1111 1112 /* Days are what is left over (+1) from all that. */ 1113 tm->tm_mday = day + 1; 1114 1115 /* 1116 * No-one uses the day of the week. 1117 */ 1118 tm->tm_wday = -1; 1119 } 1120 EXPORT_SYMBOL(to_tm); 1121 1122 /* 1123 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 1124 * result. 1125 */ 1126 void div128_by_32(u64 dividend_high, u64 dividend_low, 1127 unsigned divisor, struct div_result *dr) 1128 { 1129 unsigned long a, b, c, d; 1130 unsigned long w, x, y, z; 1131 u64 ra, rb, rc; 1132 1133 a = dividend_high >> 32; 1134 b = dividend_high & 0xffffffff; 1135 c = dividend_low >> 32; 1136 d = dividend_low & 0xffffffff; 1137 1138 w = a / divisor; 1139 ra = ((u64)(a - (w * divisor)) << 32) + b; 1140 1141 rb = ((u64) do_div(ra, divisor) << 32) + c; 1142 x = ra; 1143 1144 rc = ((u64) do_div(rb, divisor) << 32) + d; 1145 y = rb; 1146 1147 do_div(rc, divisor); 1148 z = rc; 1149 1150 dr->result_high = ((u64)w << 32) + x; 1151 dr->result_low = ((u64)y << 32) + z; 1152 1153 } 1154 1155 /* We don't need to calibrate delay, we use the CPU timebase for that */ 1156 void calibrate_delay(void) 1157 { 1158 /* Some generic code (such as spinlock debug) use loops_per_jiffy 1159 * as the number of __delay(1) in a jiffy, so make it so 1160 */ 1161 loops_per_jiffy = tb_ticks_per_jiffy; 1162 } 1163 1164 #if IS_ENABLED(CONFIG_RTC_DRV_GENERIC) 1165 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm) 1166 { 1167 ppc_md.get_rtc_time(tm); 1168 return rtc_valid_tm(tm); 1169 } 1170 1171 static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm) 1172 { 1173 if (!ppc_md.set_rtc_time) 1174 return -EOPNOTSUPP; 1175 1176 if (ppc_md.set_rtc_time(tm) < 0) 1177 return -EOPNOTSUPP; 1178 1179 return 0; 1180 } 1181 1182 static const struct rtc_class_ops rtc_generic_ops = { 1183 .read_time = rtc_generic_get_time, 1184 .set_time = rtc_generic_set_time, 1185 }; 1186 1187 static int __init rtc_init(void) 1188 { 1189 struct platform_device *pdev; 1190 1191 if (!ppc_md.get_rtc_time) 1192 return -ENODEV; 1193 1194 pdev = platform_device_register_data(NULL, "rtc-generic", -1, 1195 &rtc_generic_ops, 1196 sizeof(rtc_generic_ops)); 1197 1198 return PTR_ERR_OR_ZERO(pdev); 1199 } 1200 1201 device_initcall(rtc_init); 1202 #endif 1203