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