11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * processor_idle - idle state submodule to the ACPI processor driver 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com> 51da177e4SLinus Torvalds * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com> 61da177e4SLinus Torvalds * Copyright (C) 2004 Dominik Brodowski <linux@brodo.de> 71da177e4SLinus Torvalds * Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> 81da177e4SLinus Torvalds * - Added processor hotplug support 902df8b93SVenkatesh Pallipadi * Copyright (C) 2005 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> 1002df8b93SVenkatesh Pallipadi * - Added support for C3 on SMP 111da177e4SLinus Torvalds * 121da177e4SLinus Torvalds * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 131da177e4SLinus Torvalds * 141da177e4SLinus Torvalds * This program is free software; you can redistribute it and/or modify 151da177e4SLinus Torvalds * it under the terms of the GNU General Public License as published by 161da177e4SLinus Torvalds * the Free Software Foundation; either version 2 of the License, or (at 171da177e4SLinus Torvalds * your option) any later version. 181da177e4SLinus Torvalds * 191da177e4SLinus Torvalds * This program is distributed in the hope that it will be useful, but 201da177e4SLinus Torvalds * WITHOUT ANY WARRANTY; without even the implied warranty of 211da177e4SLinus Torvalds * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 221da177e4SLinus Torvalds * General Public License for more details. 231da177e4SLinus Torvalds * 241da177e4SLinus Torvalds * You should have received a copy of the GNU General Public License along 251da177e4SLinus Torvalds * with this program; if not, write to the Free Software Foundation, Inc., 261da177e4SLinus Torvalds * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. 271da177e4SLinus Torvalds * 281da177e4SLinus Torvalds * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 291da177e4SLinus Torvalds */ 301da177e4SLinus Torvalds 311da177e4SLinus Torvalds #include <linux/kernel.h> 321da177e4SLinus Torvalds #include <linux/module.h> 331da177e4SLinus Torvalds #include <linux/init.h> 341da177e4SLinus Torvalds #include <linux/cpufreq.h> 351da177e4SLinus Torvalds #include <linux/proc_fs.h> 361da177e4SLinus Torvalds #include <linux/seq_file.h> 371da177e4SLinus Torvalds #include <linux/acpi.h> 381da177e4SLinus Torvalds #include <linux/dmi.h> 391da177e4SLinus Torvalds #include <linux/moduleparam.h> 404e57b681STim Schmielau #include <linux/sched.h> /* need_resched() */ 411da177e4SLinus Torvalds 421da177e4SLinus Torvalds #include <asm/io.h> 431da177e4SLinus Torvalds #include <asm/uaccess.h> 441da177e4SLinus Torvalds 451da177e4SLinus Torvalds #include <acpi/acpi_bus.h> 461da177e4SLinus Torvalds #include <acpi/processor.h> 471da177e4SLinus Torvalds 481da177e4SLinus Torvalds #define ACPI_PROCESSOR_COMPONENT 0x01000000 491da177e4SLinus Torvalds #define ACPI_PROCESSOR_CLASS "processor" 501da177e4SLinus Torvalds #define ACPI_PROCESSOR_DRIVER_NAME "ACPI Processor Driver" 511da177e4SLinus Torvalds #define _COMPONENT ACPI_PROCESSOR_COMPONENT 521da177e4SLinus Torvalds ACPI_MODULE_NAME("acpi_processor") 531da177e4SLinus Torvalds #define ACPI_PROCESSOR_FILE_POWER "power" 541da177e4SLinus Torvalds #define US_TO_PM_TIMER_TICKS(t) ((t * (PM_TIMER_FREQUENCY/1000)) / 1000) 551da177e4SLinus Torvalds #define C2_OVERHEAD 4 /* 1us (3.579 ticks per us) */ 561da177e4SLinus Torvalds #define C3_OVERHEAD 4 /* 1us (3.579 ticks per us) */ 571da177e4SLinus Torvalds static void (*pm_idle_save) (void); 581da177e4SLinus Torvalds module_param(max_cstate, uint, 0644); 591da177e4SLinus Torvalds 601da177e4SLinus Torvalds static unsigned int nocst = 0; 611da177e4SLinus Torvalds module_param(nocst, uint, 0000); 621da177e4SLinus Torvalds 631da177e4SLinus Torvalds /* 641da177e4SLinus Torvalds * bm_history -- bit-mask with a bit per jiffy of bus-master activity 651da177e4SLinus Torvalds * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms 661da177e4SLinus Torvalds * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms 671da177e4SLinus Torvalds * 100 HZ: 0x0000000F: 4 jiffies = 40ms 681da177e4SLinus Torvalds * reduce history for more aggressive entry into C3 691da177e4SLinus Torvalds */ 704be44fcdSLen Brown static unsigned int bm_history = 714be44fcdSLen Brown (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1)); 721da177e4SLinus Torvalds module_param(bm_history, uint, 0644); 731da177e4SLinus Torvalds /* -------------------------------------------------------------------------- 741da177e4SLinus Torvalds Power Management 751da177e4SLinus Torvalds -------------------------------------------------------------------------- */ 761da177e4SLinus Torvalds 771da177e4SLinus Torvalds /* 781da177e4SLinus Torvalds * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3. 791da177e4SLinus Torvalds * For now disable this. Probably a bug somewhere else. 801da177e4SLinus Torvalds * 811da177e4SLinus Torvalds * To skip this limit, boot/load with a large max_cstate limit. 821da177e4SLinus Torvalds */ 83335f16beSDavid Shaohua Li static int set_max_cstate(struct dmi_system_id *id) 841da177e4SLinus Torvalds { 851da177e4SLinus Torvalds if (max_cstate > ACPI_PROCESSOR_MAX_POWER) 861da177e4SLinus Torvalds return 0; 871da177e4SLinus Torvalds 883d35600aSLen Brown printk(KERN_NOTICE PREFIX "%s detected - limiting to C%ld max_cstate." 891da177e4SLinus Torvalds " Override with \"processor.max_cstate=%d\"\n", id->ident, 903d35600aSLen Brown (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1); 911da177e4SLinus Torvalds 923d35600aSLen Brown max_cstate = (long)id->driver_data; 931da177e4SLinus Torvalds 941da177e4SLinus Torvalds return 0; 951da177e4SLinus Torvalds } 961da177e4SLinus Torvalds 971da177e4SLinus Torvalds static struct dmi_system_id __initdata processor_power_dmi_table[] = { 98335f16beSDavid Shaohua Li {set_max_cstate, "IBM ThinkPad R40e", { 994be44fcdSLen Brown DMI_MATCH(DMI_BIOS_VENDOR, 1004be44fcdSLen Brown "IBM"), 1014be44fcdSLen Brown DMI_MATCH(DMI_BIOS_VERSION, 1024be44fcdSLen Brown "1SET60WW")}, 1034be44fcdSLen Brown (void *)1}, 104335f16beSDavid Shaohua Li {set_max_cstate, "Medion 41700", { 1054be44fcdSLen Brown DMI_MATCH(DMI_BIOS_VENDOR, 1064be44fcdSLen Brown "Phoenix Technologies LTD"), 1074be44fcdSLen Brown DMI_MATCH(DMI_BIOS_VERSION, 1084be44fcdSLen Brown "R01-A1J")}, (void *)1}, 109335f16beSDavid Shaohua Li {set_max_cstate, "Clevo 5600D", { 1104be44fcdSLen Brown DMI_MATCH(DMI_BIOS_VENDOR, 1114be44fcdSLen Brown "Phoenix Technologies LTD"), 1124be44fcdSLen Brown DMI_MATCH(DMI_BIOS_VERSION, 1134be44fcdSLen Brown "SHE845M0.86C.0013.D.0302131307")}, 114335f16beSDavid Shaohua Li (void *)2}, 1151da177e4SLinus Torvalds {}, 1161da177e4SLinus Torvalds }; 1171da177e4SLinus Torvalds 1184be44fcdSLen Brown static inline u32 ticks_elapsed(u32 t1, u32 t2) 1191da177e4SLinus Torvalds { 1201da177e4SLinus Torvalds if (t2 >= t1) 1211da177e4SLinus Torvalds return (t2 - t1); 1221da177e4SLinus Torvalds else if (!acpi_fadt.tmr_val_ext) 1231da177e4SLinus Torvalds return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF); 1241da177e4SLinus Torvalds else 1251da177e4SLinus Torvalds return ((0xFFFFFFFF - t1) + t2); 1261da177e4SLinus Torvalds } 1271da177e4SLinus Torvalds 1281da177e4SLinus Torvalds static void 1294be44fcdSLen Brown acpi_processor_power_activate(struct acpi_processor *pr, 1301da177e4SLinus Torvalds struct acpi_processor_cx *new) 1311da177e4SLinus Torvalds { 1321da177e4SLinus Torvalds struct acpi_processor_cx *old; 1331da177e4SLinus Torvalds 1341da177e4SLinus Torvalds if (!pr || !new) 1351da177e4SLinus Torvalds return; 1361da177e4SLinus Torvalds 1371da177e4SLinus Torvalds old = pr->power.state; 1381da177e4SLinus Torvalds 1391da177e4SLinus Torvalds if (old) 1401da177e4SLinus Torvalds old->promotion.count = 0; 1411da177e4SLinus Torvalds new->demotion.count = 0; 1421da177e4SLinus Torvalds 1431da177e4SLinus Torvalds /* Cleanup from old state. */ 1441da177e4SLinus Torvalds if (old) { 1451da177e4SLinus Torvalds switch (old->type) { 1461da177e4SLinus Torvalds case ACPI_STATE_C3: 1471da177e4SLinus Torvalds /* Disable bus master reload */ 14802df8b93SVenkatesh Pallipadi if (new->type != ACPI_STATE_C3 && pr->flags.bm_check) 1494be44fcdSLen Brown acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0, 1504be44fcdSLen Brown ACPI_MTX_DO_NOT_LOCK); 1511da177e4SLinus Torvalds break; 1521da177e4SLinus Torvalds } 1531da177e4SLinus Torvalds } 1541da177e4SLinus Torvalds 1551da177e4SLinus Torvalds /* Prepare to use new state. */ 1561da177e4SLinus Torvalds switch (new->type) { 1571da177e4SLinus Torvalds case ACPI_STATE_C3: 1581da177e4SLinus Torvalds /* Enable bus master reload */ 15902df8b93SVenkatesh Pallipadi if (old->type != ACPI_STATE_C3 && pr->flags.bm_check) 1604be44fcdSLen Brown acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1, 1614be44fcdSLen Brown ACPI_MTX_DO_NOT_LOCK); 1621da177e4SLinus Torvalds break; 1631da177e4SLinus Torvalds } 1641da177e4SLinus Torvalds 1651da177e4SLinus Torvalds pr->power.state = new; 1661da177e4SLinus Torvalds 1671da177e4SLinus Torvalds return; 1681da177e4SLinus Torvalds } 1691da177e4SLinus Torvalds 17064c7c8f8SNick Piggin static void acpi_safe_halt(void) 17164c7c8f8SNick Piggin { 17264c7c8f8SNick Piggin int polling = test_thread_flag(TIF_POLLING_NRFLAG); 17364c7c8f8SNick Piggin if (polling) { 17464c7c8f8SNick Piggin clear_thread_flag(TIF_POLLING_NRFLAG); 17564c7c8f8SNick Piggin smp_mb__after_clear_bit(); 17664c7c8f8SNick Piggin } 17764c7c8f8SNick Piggin if (!need_resched()) 17864c7c8f8SNick Piggin safe_halt(); 17964c7c8f8SNick Piggin if (polling) 18064c7c8f8SNick Piggin set_thread_flag(TIF_POLLING_NRFLAG); 18164c7c8f8SNick Piggin } 18264c7c8f8SNick Piggin 18302df8b93SVenkatesh Pallipadi static atomic_t c3_cpu_count; 18402df8b93SVenkatesh Pallipadi 1851da177e4SLinus Torvalds static void acpi_processor_idle(void) 1861da177e4SLinus Torvalds { 1871da177e4SLinus Torvalds struct acpi_processor *pr = NULL; 1881da177e4SLinus Torvalds struct acpi_processor_cx *cx = NULL; 1891da177e4SLinus Torvalds struct acpi_processor_cx *next_state = NULL; 1901da177e4SLinus Torvalds int sleep_ticks = 0; 1911da177e4SLinus Torvalds u32 t1, t2 = 0; 1921da177e4SLinus Torvalds 19364c7c8f8SNick Piggin pr = processors[smp_processor_id()]; 1941da177e4SLinus Torvalds if (!pr) 1951da177e4SLinus Torvalds return; 1961da177e4SLinus Torvalds 1971da177e4SLinus Torvalds /* 1981da177e4SLinus Torvalds * Interrupts must be disabled during bus mastering calculations and 1991da177e4SLinus Torvalds * for C2/C3 transitions. 2001da177e4SLinus Torvalds */ 2011da177e4SLinus Torvalds local_irq_disable(); 2021da177e4SLinus Torvalds 2031da177e4SLinus Torvalds /* 2041da177e4SLinus Torvalds * Check whether we truly need to go idle, or should 2051da177e4SLinus Torvalds * reschedule: 2061da177e4SLinus Torvalds */ 2071da177e4SLinus Torvalds if (unlikely(need_resched())) { 2081da177e4SLinus Torvalds local_irq_enable(); 2091da177e4SLinus Torvalds return; 2101da177e4SLinus Torvalds } 2111da177e4SLinus Torvalds 2121da177e4SLinus Torvalds cx = pr->power.state; 21364c7c8f8SNick Piggin if (!cx) { 21464c7c8f8SNick Piggin if (pm_idle_save) 21564c7c8f8SNick Piggin pm_idle_save(); 21664c7c8f8SNick Piggin else 21764c7c8f8SNick Piggin acpi_safe_halt(); 21864c7c8f8SNick Piggin return; 21964c7c8f8SNick Piggin } 2201da177e4SLinus Torvalds 2211da177e4SLinus Torvalds /* 2221da177e4SLinus Torvalds * Check BM Activity 2231da177e4SLinus Torvalds * ----------------- 2241da177e4SLinus Torvalds * Check for bus mastering activity (if required), record, and check 2251da177e4SLinus Torvalds * for demotion. 2261da177e4SLinus Torvalds */ 2271da177e4SLinus Torvalds if (pr->flags.bm_check) { 2281da177e4SLinus Torvalds u32 bm_status = 0; 2291da177e4SLinus Torvalds unsigned long diff = jiffies - pr->power.bm_check_timestamp; 2301da177e4SLinus Torvalds 2311da177e4SLinus Torvalds if (diff > 32) 2321da177e4SLinus Torvalds diff = 32; 2331da177e4SLinus Torvalds 2341da177e4SLinus Torvalds while (diff) { 2351da177e4SLinus Torvalds /* if we didn't get called, assume there was busmaster activity */ 2361da177e4SLinus Torvalds diff--; 2371da177e4SLinus Torvalds if (diff) 2381da177e4SLinus Torvalds pr->power.bm_activity |= 0x1; 2391da177e4SLinus Torvalds pr->power.bm_activity <<= 1; 2401da177e4SLinus Torvalds } 2411da177e4SLinus Torvalds 2421da177e4SLinus Torvalds acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, 2431da177e4SLinus Torvalds &bm_status, ACPI_MTX_DO_NOT_LOCK); 2441da177e4SLinus Torvalds if (bm_status) { 2451da177e4SLinus Torvalds pr->power.bm_activity++; 2461da177e4SLinus Torvalds acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 2471da177e4SLinus Torvalds 1, ACPI_MTX_DO_NOT_LOCK); 2481da177e4SLinus Torvalds } 2491da177e4SLinus Torvalds /* 2501da177e4SLinus Torvalds * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect 2511da177e4SLinus Torvalds * the true state of bus mastering activity; forcing us to 2521da177e4SLinus Torvalds * manually check the BMIDEA bit of each IDE channel. 2531da177e4SLinus Torvalds */ 2541da177e4SLinus Torvalds else if (errata.piix4.bmisx) { 2551da177e4SLinus Torvalds if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01) 2561da177e4SLinus Torvalds || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01)) 2571da177e4SLinus Torvalds pr->power.bm_activity++; 2581da177e4SLinus Torvalds } 2591da177e4SLinus Torvalds 2601da177e4SLinus Torvalds pr->power.bm_check_timestamp = jiffies; 2611da177e4SLinus Torvalds 2621da177e4SLinus Torvalds /* 2631da177e4SLinus Torvalds * Apply bus mastering demotion policy. Automatically demote 2641da177e4SLinus Torvalds * to avoid a faulty transition. Note that the processor 2651da177e4SLinus Torvalds * won't enter a low-power state during this call (to this 2661da177e4SLinus Torvalds * funciton) but should upon the next. 2671da177e4SLinus Torvalds * 2681da177e4SLinus Torvalds * TBD: A better policy might be to fallback to the demotion 2691da177e4SLinus Torvalds * state (use it for this quantum only) istead of 2701da177e4SLinus Torvalds * demoting -- and rely on duration as our sole demotion 2711da177e4SLinus Torvalds * qualification. This may, however, introduce DMA 2721da177e4SLinus Torvalds * issues (e.g. floppy DMA transfer overrun/underrun). 2731da177e4SLinus Torvalds */ 2741da177e4SLinus Torvalds if (pr->power.bm_activity & cx->demotion.threshold.bm) { 2751da177e4SLinus Torvalds local_irq_enable(); 2761da177e4SLinus Torvalds next_state = cx->demotion.state; 2771da177e4SLinus Torvalds goto end; 2781da177e4SLinus Torvalds } 2791da177e4SLinus Torvalds } 2801da177e4SLinus Torvalds 2811da177e4SLinus Torvalds cx->usage++; 2821da177e4SLinus Torvalds 2834c033552SVenkatesh Pallipadi #ifdef CONFIG_HOTPLUG_CPU 2844c033552SVenkatesh Pallipadi /* 2854c033552SVenkatesh Pallipadi * Check for P_LVL2_UP flag before entering C2 and above on 2864c033552SVenkatesh Pallipadi * an SMP system. We do it here instead of doing it at _CST/P_LVL 2874c033552SVenkatesh Pallipadi * detection phase, to work cleanly with logical CPU hotplug. 2884c033552SVenkatesh Pallipadi */ 2894c033552SVenkatesh Pallipadi if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) && 2904c033552SVenkatesh Pallipadi !pr->flags.has_cst && acpi_fadt.plvl2_up) 2914c033552SVenkatesh Pallipadi cx->type = ACPI_STATE_C1; 2924c033552SVenkatesh Pallipadi #endif 2931da177e4SLinus Torvalds /* 2941da177e4SLinus Torvalds * Sleep: 2951da177e4SLinus Torvalds * ------ 2961da177e4SLinus Torvalds * Invoke the current Cx state to put the processor to sleep. 2971da177e4SLinus Torvalds */ 2981da177e4SLinus Torvalds switch (cx->type) { 2991da177e4SLinus Torvalds 3001da177e4SLinus Torvalds case ACPI_STATE_C1: 3011da177e4SLinus Torvalds /* 3021da177e4SLinus Torvalds * Invoke C1. 3031da177e4SLinus Torvalds * Use the appropriate idle routine, the one that would 3041da177e4SLinus Torvalds * be used without acpi C-states. 3051da177e4SLinus Torvalds */ 3061da177e4SLinus Torvalds if (pm_idle_save) 3071da177e4SLinus Torvalds pm_idle_save(); 3081da177e4SLinus Torvalds else 30964c7c8f8SNick Piggin acpi_safe_halt(); 31064c7c8f8SNick Piggin 3111da177e4SLinus Torvalds /* 3121da177e4SLinus Torvalds * TBD: Can't get time duration while in C1, as resumes 3131da177e4SLinus Torvalds * go to an ISR rather than here. Need to instrument 3141da177e4SLinus Torvalds * base interrupt handler. 3151da177e4SLinus Torvalds */ 3161da177e4SLinus Torvalds sleep_ticks = 0xFFFFFFFF; 3171da177e4SLinus Torvalds break; 3181da177e4SLinus Torvalds 3191da177e4SLinus Torvalds case ACPI_STATE_C2: 3201da177e4SLinus Torvalds /* Get start time (ticks) */ 3211da177e4SLinus Torvalds t1 = inl(acpi_fadt.xpm_tmr_blk.address); 3221da177e4SLinus Torvalds /* Invoke C2 */ 3231da177e4SLinus Torvalds inb(cx->address); 3241da177e4SLinus Torvalds /* Dummy op - must do something useless after P_LVL2 read */ 3251da177e4SLinus Torvalds t2 = inl(acpi_fadt.xpm_tmr_blk.address); 3261da177e4SLinus Torvalds /* Get end time (ticks) */ 3271da177e4SLinus Torvalds t2 = inl(acpi_fadt.xpm_tmr_blk.address); 3281da177e4SLinus Torvalds /* Re-enable interrupts */ 3291da177e4SLinus Torvalds local_irq_enable(); 3301da177e4SLinus Torvalds /* Compute time (ticks) that we were actually asleep */ 3314be44fcdSLen Brown sleep_ticks = 3324be44fcdSLen Brown ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD; 3331da177e4SLinus Torvalds break; 3341da177e4SLinus Torvalds 3351da177e4SLinus Torvalds case ACPI_STATE_C3: 33602df8b93SVenkatesh Pallipadi 33702df8b93SVenkatesh Pallipadi if (pr->flags.bm_check) { 33802df8b93SVenkatesh Pallipadi if (atomic_inc_return(&c3_cpu_count) == 33902df8b93SVenkatesh Pallipadi num_online_cpus()) { 34002df8b93SVenkatesh Pallipadi /* 34102df8b93SVenkatesh Pallipadi * All CPUs are trying to go to C3 34202df8b93SVenkatesh Pallipadi * Disable bus master arbitration 34302df8b93SVenkatesh Pallipadi */ 34402df8b93SVenkatesh Pallipadi acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1, 34502df8b93SVenkatesh Pallipadi ACPI_MTX_DO_NOT_LOCK); 34602df8b93SVenkatesh Pallipadi } 34702df8b93SVenkatesh Pallipadi } else { 34802df8b93SVenkatesh Pallipadi /* SMP with no shared cache... Invalidate cache */ 34902df8b93SVenkatesh Pallipadi ACPI_FLUSH_CPU_CACHE(); 35002df8b93SVenkatesh Pallipadi } 35102df8b93SVenkatesh Pallipadi 3521da177e4SLinus Torvalds /* Get start time (ticks) */ 3531da177e4SLinus Torvalds t1 = inl(acpi_fadt.xpm_tmr_blk.address); 3541da177e4SLinus Torvalds /* Invoke C3 */ 3551da177e4SLinus Torvalds inb(cx->address); 3561da177e4SLinus Torvalds /* Dummy op - must do something useless after P_LVL3 read */ 3571da177e4SLinus Torvalds t2 = inl(acpi_fadt.xpm_tmr_blk.address); 3581da177e4SLinus Torvalds /* Get end time (ticks) */ 3591da177e4SLinus Torvalds t2 = inl(acpi_fadt.xpm_tmr_blk.address); 36002df8b93SVenkatesh Pallipadi if (pr->flags.bm_check) { 3611da177e4SLinus Torvalds /* Enable bus master arbitration */ 36202df8b93SVenkatesh Pallipadi atomic_dec(&c3_cpu_count); 3634be44fcdSLen Brown acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0, 3644be44fcdSLen Brown ACPI_MTX_DO_NOT_LOCK); 36502df8b93SVenkatesh Pallipadi } 36602df8b93SVenkatesh Pallipadi 3671da177e4SLinus Torvalds /* Re-enable interrupts */ 3681da177e4SLinus Torvalds local_irq_enable(); 3691da177e4SLinus Torvalds /* Compute time (ticks) that we were actually asleep */ 3704be44fcdSLen Brown sleep_ticks = 3714be44fcdSLen Brown ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD; 3721da177e4SLinus Torvalds break; 3731da177e4SLinus Torvalds 3741da177e4SLinus Torvalds default: 3751da177e4SLinus Torvalds local_irq_enable(); 3761da177e4SLinus Torvalds return; 3771da177e4SLinus Torvalds } 3781da177e4SLinus Torvalds 3791da177e4SLinus Torvalds next_state = pr->power.state; 3801da177e4SLinus Torvalds 3811da177e4SLinus Torvalds /* 3821da177e4SLinus Torvalds * Promotion? 3831da177e4SLinus Torvalds * ---------- 3841da177e4SLinus Torvalds * Track the number of longs (time asleep is greater than threshold) 3851da177e4SLinus Torvalds * and promote when the count threshold is reached. Note that bus 3861da177e4SLinus Torvalds * mastering activity may prevent promotions. 3871da177e4SLinus Torvalds * Do not promote above max_cstate. 3881da177e4SLinus Torvalds */ 3891da177e4SLinus Torvalds if (cx->promotion.state && 3901da177e4SLinus Torvalds ((cx->promotion.state - pr->power.states) <= max_cstate)) { 3911da177e4SLinus Torvalds if (sleep_ticks > cx->promotion.threshold.ticks) { 3921da177e4SLinus Torvalds cx->promotion.count++; 3931da177e4SLinus Torvalds cx->demotion.count = 0; 3944be44fcdSLen Brown if (cx->promotion.count >= 3954be44fcdSLen Brown cx->promotion.threshold.count) { 3961da177e4SLinus Torvalds if (pr->flags.bm_check) { 3974be44fcdSLen Brown if (! 3984be44fcdSLen Brown (pr->power.bm_activity & cx-> 3994be44fcdSLen Brown promotion.threshold.bm)) { 4004be44fcdSLen Brown next_state = 4014be44fcdSLen Brown cx->promotion.state; 4021da177e4SLinus Torvalds goto end; 4031da177e4SLinus Torvalds } 4044be44fcdSLen Brown } else { 4051da177e4SLinus Torvalds next_state = cx->promotion.state; 4061da177e4SLinus Torvalds goto end; 4071da177e4SLinus Torvalds } 4081da177e4SLinus Torvalds } 4091da177e4SLinus Torvalds } 4101da177e4SLinus Torvalds } 4111da177e4SLinus Torvalds 4121da177e4SLinus Torvalds /* 4131da177e4SLinus Torvalds * Demotion? 4141da177e4SLinus Torvalds * --------- 4151da177e4SLinus Torvalds * Track the number of shorts (time asleep is less than time threshold) 4161da177e4SLinus Torvalds * and demote when the usage threshold is reached. 4171da177e4SLinus Torvalds */ 4181da177e4SLinus Torvalds if (cx->demotion.state) { 4191da177e4SLinus Torvalds if (sleep_ticks < cx->demotion.threshold.ticks) { 4201da177e4SLinus Torvalds cx->demotion.count++; 4211da177e4SLinus Torvalds cx->promotion.count = 0; 4221da177e4SLinus Torvalds if (cx->demotion.count >= cx->demotion.threshold.count) { 4231da177e4SLinus Torvalds next_state = cx->demotion.state; 4241da177e4SLinus Torvalds goto end; 4251da177e4SLinus Torvalds } 4261da177e4SLinus Torvalds } 4271da177e4SLinus Torvalds } 4281da177e4SLinus Torvalds 4291da177e4SLinus Torvalds end: 4301da177e4SLinus Torvalds /* 4311da177e4SLinus Torvalds * Demote if current state exceeds max_cstate 4321da177e4SLinus Torvalds */ 4331da177e4SLinus Torvalds if ((pr->power.state - pr->power.states) > max_cstate) { 4341da177e4SLinus Torvalds if (cx->demotion.state) 4351da177e4SLinus Torvalds next_state = cx->demotion.state; 4361da177e4SLinus Torvalds } 4371da177e4SLinus Torvalds 4381da177e4SLinus Torvalds /* 4391da177e4SLinus Torvalds * New Cx State? 4401da177e4SLinus Torvalds * ------------- 4411da177e4SLinus Torvalds * If we're going to start using a new Cx state we must clean up 4421da177e4SLinus Torvalds * from the previous and prepare to use the new. 4431da177e4SLinus Torvalds */ 4441da177e4SLinus Torvalds if (next_state != pr->power.state) 4451da177e4SLinus Torvalds acpi_processor_power_activate(pr, next_state); 4461da177e4SLinus Torvalds } 4471da177e4SLinus Torvalds 4484be44fcdSLen Brown static int acpi_processor_set_power_policy(struct acpi_processor *pr) 4491da177e4SLinus Torvalds { 4501da177e4SLinus Torvalds unsigned int i; 4511da177e4SLinus Torvalds unsigned int state_is_set = 0; 4521da177e4SLinus Torvalds struct acpi_processor_cx *lower = NULL; 4531da177e4SLinus Torvalds struct acpi_processor_cx *higher = NULL; 4541da177e4SLinus Torvalds struct acpi_processor_cx *cx; 4551da177e4SLinus Torvalds 4561da177e4SLinus Torvalds ACPI_FUNCTION_TRACE("acpi_processor_set_power_policy"); 4571da177e4SLinus Torvalds 4581da177e4SLinus Torvalds if (!pr) 4591da177e4SLinus Torvalds return_VALUE(-EINVAL); 4601da177e4SLinus Torvalds 4611da177e4SLinus Torvalds /* 4621da177e4SLinus Torvalds * This function sets the default Cx state policy (OS idle handler). 4631da177e4SLinus Torvalds * Our scheme is to promote quickly to C2 but more conservatively 4641da177e4SLinus Torvalds * to C3. We're favoring C2 for its characteristics of low latency 4651da177e4SLinus Torvalds * (quick response), good power savings, and ability to allow bus 4661da177e4SLinus Torvalds * mastering activity. Note that the Cx state policy is completely 4671da177e4SLinus Torvalds * customizable and can be altered dynamically. 4681da177e4SLinus Torvalds */ 4691da177e4SLinus Torvalds 4701da177e4SLinus Torvalds /* startup state */ 4711da177e4SLinus Torvalds for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { 4721da177e4SLinus Torvalds cx = &pr->power.states[i]; 4731da177e4SLinus Torvalds if (!cx->valid) 4741da177e4SLinus Torvalds continue; 4751da177e4SLinus Torvalds 4761da177e4SLinus Torvalds if (!state_is_set) 4771da177e4SLinus Torvalds pr->power.state = cx; 4781da177e4SLinus Torvalds state_is_set++; 4791da177e4SLinus Torvalds break; 4801da177e4SLinus Torvalds } 4811da177e4SLinus Torvalds 4821da177e4SLinus Torvalds if (!state_is_set) 4831da177e4SLinus Torvalds return_VALUE(-ENODEV); 4841da177e4SLinus Torvalds 4851da177e4SLinus Torvalds /* demotion */ 4861da177e4SLinus Torvalds for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { 4871da177e4SLinus Torvalds cx = &pr->power.states[i]; 4881da177e4SLinus Torvalds if (!cx->valid) 4891da177e4SLinus Torvalds continue; 4901da177e4SLinus Torvalds 4911da177e4SLinus Torvalds if (lower) { 4921da177e4SLinus Torvalds cx->demotion.state = lower; 4931da177e4SLinus Torvalds cx->demotion.threshold.ticks = cx->latency_ticks; 4941da177e4SLinus Torvalds cx->demotion.threshold.count = 1; 4951da177e4SLinus Torvalds if (cx->type == ACPI_STATE_C3) 4961da177e4SLinus Torvalds cx->demotion.threshold.bm = bm_history; 4971da177e4SLinus Torvalds } 4981da177e4SLinus Torvalds 4991da177e4SLinus Torvalds lower = cx; 5001da177e4SLinus Torvalds } 5011da177e4SLinus Torvalds 5021da177e4SLinus Torvalds /* promotion */ 5031da177e4SLinus Torvalds for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) { 5041da177e4SLinus Torvalds cx = &pr->power.states[i]; 5051da177e4SLinus Torvalds if (!cx->valid) 5061da177e4SLinus Torvalds continue; 5071da177e4SLinus Torvalds 5081da177e4SLinus Torvalds if (higher) { 5091da177e4SLinus Torvalds cx->promotion.state = higher; 5101da177e4SLinus Torvalds cx->promotion.threshold.ticks = cx->latency_ticks; 5111da177e4SLinus Torvalds if (cx->type >= ACPI_STATE_C2) 5121da177e4SLinus Torvalds cx->promotion.threshold.count = 4; 5131da177e4SLinus Torvalds else 5141da177e4SLinus Torvalds cx->promotion.threshold.count = 10; 5151da177e4SLinus Torvalds if (higher->type == ACPI_STATE_C3) 5161da177e4SLinus Torvalds cx->promotion.threshold.bm = bm_history; 5171da177e4SLinus Torvalds } 5181da177e4SLinus Torvalds 5191da177e4SLinus Torvalds higher = cx; 5201da177e4SLinus Torvalds } 5211da177e4SLinus Torvalds 5221da177e4SLinus Torvalds return_VALUE(0); 5231da177e4SLinus Torvalds } 5241da177e4SLinus Torvalds 5251da177e4SLinus Torvalds static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr) 5261da177e4SLinus Torvalds { 5271da177e4SLinus Torvalds ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_fadt"); 5281da177e4SLinus Torvalds 5291da177e4SLinus Torvalds if (!pr) 5301da177e4SLinus Torvalds return_VALUE(-EINVAL); 5311da177e4SLinus Torvalds 5321da177e4SLinus Torvalds if (!pr->pblk) 5331da177e4SLinus Torvalds return_VALUE(-ENODEV); 5341da177e4SLinus Torvalds 5352203d6edSLinus Torvalds memset(pr->power.states, 0, sizeof(pr->power.states)); 5361da177e4SLinus Torvalds 5371da177e4SLinus Torvalds /* if info is obtained from pblk/fadt, type equals state */ 5381da177e4SLinus Torvalds pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1; 5391da177e4SLinus Torvalds pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2; 5401da177e4SLinus Torvalds pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3; 5411da177e4SLinus Torvalds 5421da177e4SLinus Torvalds /* the C0 state only exists as a filler in our array, 5431da177e4SLinus Torvalds * and all processors need to support C1 */ 5441da177e4SLinus Torvalds pr->power.states[ACPI_STATE_C0].valid = 1; 5451da177e4SLinus Torvalds pr->power.states[ACPI_STATE_C1].valid = 1; 5461da177e4SLinus Torvalds 5474c033552SVenkatesh Pallipadi #ifndef CONFIG_HOTPLUG_CPU 5484c033552SVenkatesh Pallipadi /* 5494c033552SVenkatesh Pallipadi * Check for P_LVL2_UP flag before entering C2 and above on 5504c033552SVenkatesh Pallipadi * an SMP system. 5514c033552SVenkatesh Pallipadi */ 5524c033552SVenkatesh Pallipadi if ((num_online_cpus() > 1) && acpi_fadt.plvl2_up) 5534c033552SVenkatesh Pallipadi return_VALUE(-ENODEV); 5544c033552SVenkatesh Pallipadi #endif 5554c033552SVenkatesh Pallipadi 5561da177e4SLinus Torvalds /* determine C2 and C3 address from pblk */ 5571da177e4SLinus Torvalds pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4; 5581da177e4SLinus Torvalds pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5; 5591da177e4SLinus Torvalds 5601da177e4SLinus Torvalds /* determine latencies from FADT */ 5611da177e4SLinus Torvalds pr->power.states[ACPI_STATE_C2].latency = acpi_fadt.plvl2_lat; 5621da177e4SLinus Torvalds pr->power.states[ACPI_STATE_C3].latency = acpi_fadt.plvl3_lat; 5631da177e4SLinus Torvalds 5641da177e4SLinus Torvalds ACPI_DEBUG_PRINT((ACPI_DB_INFO, 5651da177e4SLinus Torvalds "lvl2[0x%08x] lvl3[0x%08x]\n", 5661da177e4SLinus Torvalds pr->power.states[ACPI_STATE_C2].address, 5671da177e4SLinus Torvalds pr->power.states[ACPI_STATE_C3].address)); 5681da177e4SLinus Torvalds 5691da177e4SLinus Torvalds return_VALUE(0); 5701da177e4SLinus Torvalds } 5711da177e4SLinus Torvalds 572acf05f4bSVenkatesh Pallipadi static int acpi_processor_get_power_info_default_c1(struct acpi_processor *pr) 573acf05f4bSVenkatesh Pallipadi { 574acf05f4bSVenkatesh Pallipadi ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_default_c1"); 575acf05f4bSVenkatesh Pallipadi 5762203d6edSLinus Torvalds memset(pr->power.states, 0, sizeof(pr->power.states)); 577acf05f4bSVenkatesh Pallipadi 578acf05f4bSVenkatesh Pallipadi /* if info is obtained from pblk/fadt, type equals state */ 579acf05f4bSVenkatesh Pallipadi pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1; 580acf05f4bSVenkatesh Pallipadi pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2; 581acf05f4bSVenkatesh Pallipadi pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3; 582acf05f4bSVenkatesh Pallipadi 583acf05f4bSVenkatesh Pallipadi /* the C0 state only exists as a filler in our array, 584acf05f4bSVenkatesh Pallipadi * and all processors need to support C1 */ 585acf05f4bSVenkatesh Pallipadi pr->power.states[ACPI_STATE_C0].valid = 1; 586acf05f4bSVenkatesh Pallipadi pr->power.states[ACPI_STATE_C1].valid = 1; 587acf05f4bSVenkatesh Pallipadi 588acf05f4bSVenkatesh Pallipadi return_VALUE(0); 589acf05f4bSVenkatesh Pallipadi } 590acf05f4bSVenkatesh Pallipadi 5911da177e4SLinus Torvalds static int acpi_processor_get_power_info_cst(struct acpi_processor *pr) 5921da177e4SLinus Torvalds { 5931da177e4SLinus Torvalds acpi_status status = 0; 5941da177e4SLinus Torvalds acpi_integer count; 5951da177e4SLinus Torvalds int i; 5961da177e4SLinus Torvalds struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; 5971da177e4SLinus Torvalds union acpi_object *cst; 5981da177e4SLinus Torvalds 5991da177e4SLinus Torvalds ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_cst"); 6001da177e4SLinus Torvalds 6011da177e4SLinus Torvalds if (nocst) 6021da177e4SLinus Torvalds return_VALUE(-ENODEV); 6031da177e4SLinus Torvalds 6041da177e4SLinus Torvalds pr->power.count = 0; 6051da177e4SLinus Torvalds for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++) 6060b6b2f08SVenkatesh Pallipadi memset(&(pr->power.states[i]), 0, 6070b6b2f08SVenkatesh Pallipadi sizeof(struct acpi_processor_cx)); 6081da177e4SLinus Torvalds 6091da177e4SLinus Torvalds status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer); 6101da177e4SLinus Torvalds if (ACPI_FAILURE(status)) { 6111da177e4SLinus Torvalds ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n")); 6121da177e4SLinus Torvalds return_VALUE(-ENODEV); 6131da177e4SLinus Torvalds } 6141da177e4SLinus Torvalds 6151da177e4SLinus Torvalds cst = (union acpi_object *)buffer.pointer; 6161da177e4SLinus Torvalds 6171da177e4SLinus Torvalds /* There must be at least 2 elements */ 6181da177e4SLinus Torvalds if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) { 6194be44fcdSLen Brown ACPI_DEBUG_PRINT((ACPI_DB_ERROR, 6204be44fcdSLen Brown "not enough elements in _CST\n")); 6211da177e4SLinus Torvalds status = -EFAULT; 6221da177e4SLinus Torvalds goto end; 6231da177e4SLinus Torvalds } 6241da177e4SLinus Torvalds 6251da177e4SLinus Torvalds count = cst->package.elements[0].integer.value; 6261da177e4SLinus Torvalds 6271da177e4SLinus Torvalds /* Validate number of power states. */ 6281da177e4SLinus Torvalds if (count < 1 || count != cst->package.count - 1) { 6294be44fcdSLen Brown ACPI_DEBUG_PRINT((ACPI_DB_ERROR, 6304be44fcdSLen Brown "count given by _CST is not valid\n")); 6311da177e4SLinus Torvalds status = -EFAULT; 6321da177e4SLinus Torvalds goto end; 6331da177e4SLinus Torvalds } 6341da177e4SLinus Torvalds 6351da177e4SLinus Torvalds /* We support up to ACPI_PROCESSOR_MAX_POWER. */ 6361da177e4SLinus Torvalds if (count > ACPI_PROCESSOR_MAX_POWER) { 6374be44fcdSLen Brown printk(KERN_WARNING 6384be44fcdSLen Brown "Limiting number of power states to max (%d)\n", 6394be44fcdSLen Brown ACPI_PROCESSOR_MAX_POWER); 6404be44fcdSLen Brown printk(KERN_WARNING 6414be44fcdSLen Brown "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n"); 6421da177e4SLinus Torvalds count = ACPI_PROCESSOR_MAX_POWER; 6431da177e4SLinus Torvalds } 6441da177e4SLinus Torvalds 6451da177e4SLinus Torvalds /* Tell driver that at least _CST is supported. */ 6461da177e4SLinus Torvalds pr->flags.has_cst = 1; 6471da177e4SLinus Torvalds 6481da177e4SLinus Torvalds for (i = 1; i <= count; i++) { 6491da177e4SLinus Torvalds union acpi_object *element; 6501da177e4SLinus Torvalds union acpi_object *obj; 6511da177e4SLinus Torvalds struct acpi_power_register *reg; 6521da177e4SLinus Torvalds struct acpi_processor_cx cx; 6531da177e4SLinus Torvalds 6541da177e4SLinus Torvalds memset(&cx, 0, sizeof(cx)); 6551da177e4SLinus Torvalds 6561da177e4SLinus Torvalds element = (union acpi_object *)&(cst->package.elements[i]); 6571da177e4SLinus Torvalds if (element->type != ACPI_TYPE_PACKAGE) 6581da177e4SLinus Torvalds continue; 6591da177e4SLinus Torvalds 6601da177e4SLinus Torvalds if (element->package.count != 4) 6611da177e4SLinus Torvalds continue; 6621da177e4SLinus Torvalds 6631da177e4SLinus Torvalds obj = (union acpi_object *)&(element->package.elements[0]); 6641da177e4SLinus Torvalds 6651da177e4SLinus Torvalds if (obj->type != ACPI_TYPE_BUFFER) 6661da177e4SLinus Torvalds continue; 6671da177e4SLinus Torvalds 6681da177e4SLinus Torvalds reg = (struct acpi_power_register *)obj->buffer.pointer; 6691da177e4SLinus Torvalds 6701da177e4SLinus Torvalds if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO && 6711da177e4SLinus Torvalds (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)) 6721da177e4SLinus Torvalds continue; 6731da177e4SLinus Torvalds 6741da177e4SLinus Torvalds cx.address = (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) ? 6751da177e4SLinus Torvalds 0 : reg->address; 6761da177e4SLinus Torvalds 6771da177e4SLinus Torvalds /* There should be an easy way to extract an integer... */ 6781da177e4SLinus Torvalds obj = (union acpi_object *)&(element->package.elements[1]); 6791da177e4SLinus Torvalds if (obj->type != ACPI_TYPE_INTEGER) 6801da177e4SLinus Torvalds continue; 6811da177e4SLinus Torvalds 6821da177e4SLinus Torvalds cx.type = obj->integer.value; 6831da177e4SLinus Torvalds 6841da177e4SLinus Torvalds if ((cx.type != ACPI_STATE_C1) && 6851da177e4SLinus Torvalds (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO)) 6861da177e4SLinus Torvalds continue; 6871da177e4SLinus Torvalds 6884be44fcdSLen Brown if ((cx.type < ACPI_STATE_C1) || (cx.type > ACPI_STATE_C3)) 6891da177e4SLinus Torvalds continue; 6901da177e4SLinus Torvalds 6911da177e4SLinus Torvalds obj = (union acpi_object *)&(element->package.elements[2]); 6921da177e4SLinus Torvalds if (obj->type != ACPI_TYPE_INTEGER) 6931da177e4SLinus Torvalds continue; 6941da177e4SLinus Torvalds 6951da177e4SLinus Torvalds cx.latency = obj->integer.value; 6961da177e4SLinus Torvalds 6971da177e4SLinus Torvalds obj = (union acpi_object *)&(element->package.elements[3]); 6981da177e4SLinus Torvalds if (obj->type != ACPI_TYPE_INTEGER) 6991da177e4SLinus Torvalds continue; 7001da177e4SLinus Torvalds 7011da177e4SLinus Torvalds cx.power = obj->integer.value; 7021da177e4SLinus Torvalds 7031da177e4SLinus Torvalds (pr->power.count)++; 7041da177e4SLinus Torvalds memcpy(&(pr->power.states[pr->power.count]), &cx, sizeof(cx)); 7051da177e4SLinus Torvalds } 7061da177e4SLinus Torvalds 7074be44fcdSLen Brown ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n", 7084be44fcdSLen Brown pr->power.count)); 7091da177e4SLinus Torvalds 7101da177e4SLinus Torvalds /* Validate number of power states discovered */ 7111da177e4SLinus Torvalds if (pr->power.count < 2) 7126d93c648SVenkatesh Pallipadi status = -EFAULT; 7131da177e4SLinus Torvalds 7141da177e4SLinus Torvalds end: 7151da177e4SLinus Torvalds acpi_os_free(buffer.pointer); 7161da177e4SLinus Torvalds 7171da177e4SLinus Torvalds return_VALUE(status); 7181da177e4SLinus Torvalds } 7191da177e4SLinus Torvalds 7201da177e4SLinus Torvalds static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx) 7211da177e4SLinus Torvalds { 7221da177e4SLinus Torvalds ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c2"); 7231da177e4SLinus Torvalds 7241da177e4SLinus Torvalds if (!cx->address) 7251da177e4SLinus Torvalds return_VOID; 7261da177e4SLinus Torvalds 7271da177e4SLinus Torvalds /* 7281da177e4SLinus Torvalds * C2 latency must be less than or equal to 100 7291da177e4SLinus Torvalds * microseconds. 7301da177e4SLinus Torvalds */ 7311da177e4SLinus Torvalds else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) { 7321da177e4SLinus Torvalds ACPI_DEBUG_PRINT((ACPI_DB_INFO, 7334be44fcdSLen Brown "latency too large [%d]\n", cx->latency)); 7341da177e4SLinus Torvalds return_VOID; 7351da177e4SLinus Torvalds } 7361da177e4SLinus Torvalds 7371da177e4SLinus Torvalds /* 7381da177e4SLinus Torvalds * Otherwise we've met all of our C2 requirements. 7391da177e4SLinus Torvalds * Normalize the C2 latency to expidite policy 7401da177e4SLinus Torvalds */ 7411da177e4SLinus Torvalds cx->valid = 1; 7421da177e4SLinus Torvalds cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency); 7431da177e4SLinus Torvalds 7441da177e4SLinus Torvalds return_VOID; 7451da177e4SLinus Torvalds } 7461da177e4SLinus Torvalds 7474be44fcdSLen Brown static void acpi_processor_power_verify_c3(struct acpi_processor *pr, 7481da177e4SLinus Torvalds struct acpi_processor_cx *cx) 7491da177e4SLinus Torvalds { 75002df8b93SVenkatesh Pallipadi static int bm_check_flag; 75102df8b93SVenkatesh Pallipadi 7521da177e4SLinus Torvalds ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c3"); 7531da177e4SLinus Torvalds 7541da177e4SLinus Torvalds if (!cx->address) 7551da177e4SLinus Torvalds return_VOID; 7561da177e4SLinus Torvalds 7571da177e4SLinus Torvalds /* 7581da177e4SLinus Torvalds * C3 latency must be less than or equal to 1000 7591da177e4SLinus Torvalds * microseconds. 7601da177e4SLinus Torvalds */ 7611da177e4SLinus Torvalds else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) { 7621da177e4SLinus Torvalds ACPI_DEBUG_PRINT((ACPI_DB_INFO, 7634be44fcdSLen Brown "latency too large [%d]\n", cx->latency)); 7641da177e4SLinus Torvalds return_VOID; 7651da177e4SLinus Torvalds } 7661da177e4SLinus Torvalds 7671da177e4SLinus Torvalds /* 7681da177e4SLinus Torvalds * PIIX4 Erratum #18: We don't support C3 when Type-F (fast) 7691da177e4SLinus Torvalds * DMA transfers are used by any ISA device to avoid livelock. 7701da177e4SLinus Torvalds * Note that we could disable Type-F DMA (as recommended by 7711da177e4SLinus Torvalds * the erratum), but this is known to disrupt certain ISA 7721da177e4SLinus Torvalds * devices thus we take the conservative approach. 7731da177e4SLinus Torvalds */ 7741da177e4SLinus Torvalds else if (errata.piix4.fdma) { 7751da177e4SLinus Torvalds ACPI_DEBUG_PRINT((ACPI_DB_INFO, 7761da177e4SLinus Torvalds "C3 not supported on PIIX4 with Type-F DMA\n")); 7771da177e4SLinus Torvalds return_VOID; 7781da177e4SLinus Torvalds } 7791da177e4SLinus Torvalds 78002df8b93SVenkatesh Pallipadi /* All the logic here assumes flags.bm_check is same across all CPUs */ 78102df8b93SVenkatesh Pallipadi if (!bm_check_flag) { 78202df8b93SVenkatesh Pallipadi /* Determine whether bm_check is needed based on CPU */ 78302df8b93SVenkatesh Pallipadi acpi_processor_power_init_bm_check(&(pr->flags), pr->id); 78402df8b93SVenkatesh Pallipadi bm_check_flag = pr->flags.bm_check; 78502df8b93SVenkatesh Pallipadi } else { 78602df8b93SVenkatesh Pallipadi pr->flags.bm_check = bm_check_flag; 78702df8b93SVenkatesh Pallipadi } 78802df8b93SVenkatesh Pallipadi 78902df8b93SVenkatesh Pallipadi if (pr->flags.bm_check) { 79002df8b93SVenkatesh Pallipadi /* bus mastering control is necessary */ 79102df8b93SVenkatesh Pallipadi if (!pr->flags.bm_control) { 79202df8b93SVenkatesh Pallipadi ACPI_DEBUG_PRINT((ACPI_DB_INFO, 79302df8b93SVenkatesh Pallipadi "C3 support requires bus mastering control\n")); 79402df8b93SVenkatesh Pallipadi return_VOID; 79502df8b93SVenkatesh Pallipadi } 79602df8b93SVenkatesh Pallipadi } else { 79702df8b93SVenkatesh Pallipadi /* 79802df8b93SVenkatesh Pallipadi * WBINVD should be set in fadt, for C3 state to be 79902df8b93SVenkatesh Pallipadi * supported on when bm_check is not required. 80002df8b93SVenkatesh Pallipadi */ 80102df8b93SVenkatesh Pallipadi if (acpi_fadt.wb_invd != 1) { 80202df8b93SVenkatesh Pallipadi ACPI_DEBUG_PRINT((ACPI_DB_INFO, 80302df8b93SVenkatesh Pallipadi "Cache invalidation should work properly" 80402df8b93SVenkatesh Pallipadi " for C3 to be enabled on SMP systems\n")); 80502df8b93SVenkatesh Pallipadi return_VOID; 80602df8b93SVenkatesh Pallipadi } 80702df8b93SVenkatesh Pallipadi acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 80802df8b93SVenkatesh Pallipadi 0, ACPI_MTX_DO_NOT_LOCK); 80902df8b93SVenkatesh Pallipadi } 81002df8b93SVenkatesh Pallipadi 8111da177e4SLinus Torvalds /* 8121da177e4SLinus Torvalds * Otherwise we've met all of our C3 requirements. 8131da177e4SLinus Torvalds * Normalize the C3 latency to expidite policy. Enable 8141da177e4SLinus Torvalds * checking of bus mastering status (bm_check) so we can 8151da177e4SLinus Torvalds * use this in our C3 policy 8161da177e4SLinus Torvalds */ 8171da177e4SLinus Torvalds cx->valid = 1; 8181da177e4SLinus Torvalds cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency); 8191da177e4SLinus Torvalds 8201da177e4SLinus Torvalds return_VOID; 8211da177e4SLinus Torvalds } 8221da177e4SLinus Torvalds 8231da177e4SLinus Torvalds static int acpi_processor_power_verify(struct acpi_processor *pr) 8241da177e4SLinus Torvalds { 8251da177e4SLinus Torvalds unsigned int i; 8261da177e4SLinus Torvalds unsigned int working = 0; 8271da177e4SLinus Torvalds 8281da177e4SLinus Torvalds for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { 8291da177e4SLinus Torvalds struct acpi_processor_cx *cx = &pr->power.states[i]; 8301da177e4SLinus Torvalds 8311da177e4SLinus Torvalds switch (cx->type) { 8321da177e4SLinus Torvalds case ACPI_STATE_C1: 8331da177e4SLinus Torvalds cx->valid = 1; 8341da177e4SLinus Torvalds break; 8351da177e4SLinus Torvalds 8361da177e4SLinus Torvalds case ACPI_STATE_C2: 8371da177e4SLinus Torvalds acpi_processor_power_verify_c2(cx); 8381da177e4SLinus Torvalds break; 8391da177e4SLinus Torvalds 8401da177e4SLinus Torvalds case ACPI_STATE_C3: 8411da177e4SLinus Torvalds acpi_processor_power_verify_c3(pr, cx); 8421da177e4SLinus Torvalds break; 8431da177e4SLinus Torvalds } 8441da177e4SLinus Torvalds 8451da177e4SLinus Torvalds if (cx->valid) 8461da177e4SLinus Torvalds working++; 8471da177e4SLinus Torvalds } 8481da177e4SLinus Torvalds 8491da177e4SLinus Torvalds return (working); 8501da177e4SLinus Torvalds } 8511da177e4SLinus Torvalds 8524be44fcdSLen Brown static int acpi_processor_get_power_info(struct acpi_processor *pr) 8531da177e4SLinus Torvalds { 8541da177e4SLinus Torvalds unsigned int i; 8551da177e4SLinus Torvalds int result; 8561da177e4SLinus Torvalds 8571da177e4SLinus Torvalds ACPI_FUNCTION_TRACE("acpi_processor_get_power_info"); 8581da177e4SLinus Torvalds 8591da177e4SLinus Torvalds /* NOTE: the idle thread may not be running while calling 8601da177e4SLinus Torvalds * this function */ 8611da177e4SLinus Torvalds 8621da177e4SLinus Torvalds result = acpi_processor_get_power_info_cst(pr); 8636d93c648SVenkatesh Pallipadi if (result == -ENODEV) 8641da177e4SLinus Torvalds result = acpi_processor_get_power_info_fadt(pr); 8656d93c648SVenkatesh Pallipadi 8664a716402SVenkatesh Pallipadi if ((result) || (acpi_processor_power_verify(pr) < 2)) 867acf05f4bSVenkatesh Pallipadi result = acpi_processor_get_power_info_default_c1(pr); 8681da177e4SLinus Torvalds 8691da177e4SLinus Torvalds /* 8701da177e4SLinus Torvalds * Set Default Policy 8711da177e4SLinus Torvalds * ------------------ 8721da177e4SLinus Torvalds * Now that we know which states are supported, set the default 8731da177e4SLinus Torvalds * policy. Note that this policy can be changed dynamically 8741da177e4SLinus Torvalds * (e.g. encourage deeper sleeps to conserve battery life when 8751da177e4SLinus Torvalds * not on AC). 8761da177e4SLinus Torvalds */ 8771da177e4SLinus Torvalds result = acpi_processor_set_power_policy(pr); 8781da177e4SLinus Torvalds if (result) 8791da177e4SLinus Torvalds return_VALUE(result); 8801da177e4SLinus Torvalds 8811da177e4SLinus Torvalds /* 8821da177e4SLinus Torvalds * if one state of type C2 or C3 is available, mark this 8831da177e4SLinus Torvalds * CPU as being "idle manageable" 8841da177e4SLinus Torvalds */ 8851da177e4SLinus Torvalds for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { 886acf05f4bSVenkatesh Pallipadi if (pr->power.states[i].valid) { 8871da177e4SLinus Torvalds pr->power.count = i; 8882203d6edSLinus Torvalds if (pr->power.states[i].type >= ACPI_STATE_C2) 8891da177e4SLinus Torvalds pr->flags.power = 1; 8901da177e4SLinus Torvalds } 891acf05f4bSVenkatesh Pallipadi } 8921da177e4SLinus Torvalds 8931da177e4SLinus Torvalds return_VALUE(0); 8941da177e4SLinus Torvalds } 8951da177e4SLinus Torvalds 8961da177e4SLinus Torvalds int acpi_processor_cst_has_changed(struct acpi_processor *pr) 8971da177e4SLinus Torvalds { 8981da177e4SLinus Torvalds int result = 0; 8991da177e4SLinus Torvalds 9001da177e4SLinus Torvalds ACPI_FUNCTION_TRACE("acpi_processor_cst_has_changed"); 9011da177e4SLinus Torvalds 9021da177e4SLinus Torvalds if (!pr) 9031da177e4SLinus Torvalds return_VALUE(-EINVAL); 9041da177e4SLinus Torvalds 90502df8b93SVenkatesh Pallipadi if (nocst) { 9061da177e4SLinus Torvalds return_VALUE(-ENODEV); 9071da177e4SLinus Torvalds } 9081da177e4SLinus Torvalds 9091da177e4SLinus Torvalds if (!pr->flags.power_setup_done) 9101da177e4SLinus Torvalds return_VALUE(-ENODEV); 9111da177e4SLinus Torvalds 9121da177e4SLinus Torvalds /* Fall back to the default idle loop */ 9131da177e4SLinus Torvalds pm_idle = pm_idle_save; 914fbd568a3SPaul E. McKenney synchronize_sched(); /* Relies on interrupts forcing exit from idle. */ 9151da177e4SLinus Torvalds 9161da177e4SLinus Torvalds pr->flags.power = 0; 9171da177e4SLinus Torvalds result = acpi_processor_get_power_info(pr); 9181da177e4SLinus Torvalds if ((pr->flags.power == 1) && (pr->flags.power_setup_done)) 9191da177e4SLinus Torvalds pm_idle = acpi_processor_idle; 9201da177e4SLinus Torvalds 9211da177e4SLinus Torvalds return_VALUE(result); 9221da177e4SLinus Torvalds } 9231da177e4SLinus Torvalds 9241da177e4SLinus Torvalds /* proc interface */ 9251da177e4SLinus Torvalds 9261da177e4SLinus Torvalds static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset) 9271da177e4SLinus Torvalds { 9281da177e4SLinus Torvalds struct acpi_processor *pr = (struct acpi_processor *)seq->private; 9291da177e4SLinus Torvalds unsigned int i; 9301da177e4SLinus Torvalds 9311da177e4SLinus Torvalds ACPI_FUNCTION_TRACE("acpi_processor_power_seq_show"); 9321da177e4SLinus Torvalds 9331da177e4SLinus Torvalds if (!pr) 9341da177e4SLinus Torvalds goto end; 9351da177e4SLinus Torvalds 9361da177e4SLinus Torvalds seq_printf(seq, "active state: C%zd\n" 9371da177e4SLinus Torvalds "max_cstate: C%d\n" 9381da177e4SLinus Torvalds "bus master activity: %08x\n", 9391da177e4SLinus Torvalds pr->power.state ? pr->power.state - pr->power.states : 0, 9404be44fcdSLen Brown max_cstate, (unsigned)pr->power.bm_activity); 9411da177e4SLinus Torvalds 9421da177e4SLinus Torvalds seq_puts(seq, "states:\n"); 9431da177e4SLinus Torvalds 9441da177e4SLinus Torvalds for (i = 1; i <= pr->power.count; i++) { 9451da177e4SLinus Torvalds seq_printf(seq, " %cC%d: ", 9464be44fcdSLen Brown (&pr->power.states[i] == 9474be44fcdSLen Brown pr->power.state ? '*' : ' '), i); 9481da177e4SLinus Torvalds 9491da177e4SLinus Torvalds if (!pr->power.states[i].valid) { 9501da177e4SLinus Torvalds seq_puts(seq, "<not supported>\n"); 9511da177e4SLinus Torvalds continue; 9521da177e4SLinus Torvalds } 9531da177e4SLinus Torvalds 9541da177e4SLinus Torvalds switch (pr->power.states[i].type) { 9551da177e4SLinus Torvalds case ACPI_STATE_C1: 9561da177e4SLinus Torvalds seq_printf(seq, "type[C1] "); 9571da177e4SLinus Torvalds break; 9581da177e4SLinus Torvalds case ACPI_STATE_C2: 9591da177e4SLinus Torvalds seq_printf(seq, "type[C2] "); 9601da177e4SLinus Torvalds break; 9611da177e4SLinus Torvalds case ACPI_STATE_C3: 9621da177e4SLinus Torvalds seq_printf(seq, "type[C3] "); 9631da177e4SLinus Torvalds break; 9641da177e4SLinus Torvalds default: 9651da177e4SLinus Torvalds seq_printf(seq, "type[--] "); 9661da177e4SLinus Torvalds break; 9671da177e4SLinus Torvalds } 9681da177e4SLinus Torvalds 9691da177e4SLinus Torvalds if (pr->power.states[i].promotion.state) 9701da177e4SLinus Torvalds seq_printf(seq, "promotion[C%zd] ", 9711da177e4SLinus Torvalds (pr->power.states[i].promotion.state - 9721da177e4SLinus Torvalds pr->power.states)); 9731da177e4SLinus Torvalds else 9741da177e4SLinus Torvalds seq_puts(seq, "promotion[--] "); 9751da177e4SLinus Torvalds 9761da177e4SLinus Torvalds if (pr->power.states[i].demotion.state) 9771da177e4SLinus Torvalds seq_printf(seq, "demotion[C%zd] ", 9781da177e4SLinus Torvalds (pr->power.states[i].demotion.state - 9791da177e4SLinus Torvalds pr->power.states)); 9801da177e4SLinus Torvalds else 9811da177e4SLinus Torvalds seq_puts(seq, "demotion[--] "); 9821da177e4SLinus Torvalds 9831da177e4SLinus Torvalds seq_printf(seq, "latency[%03d] usage[%08d]\n", 9841da177e4SLinus Torvalds pr->power.states[i].latency, 9851da177e4SLinus Torvalds pr->power.states[i].usage); 9861da177e4SLinus Torvalds } 9871da177e4SLinus Torvalds 9881da177e4SLinus Torvalds end: 9891da177e4SLinus Torvalds return_VALUE(0); 9901da177e4SLinus Torvalds } 9911da177e4SLinus Torvalds 9921da177e4SLinus Torvalds static int acpi_processor_power_open_fs(struct inode *inode, struct file *file) 9931da177e4SLinus Torvalds { 9941da177e4SLinus Torvalds return single_open(file, acpi_processor_power_seq_show, 9951da177e4SLinus Torvalds PDE(inode)->data); 9961da177e4SLinus Torvalds } 9971da177e4SLinus Torvalds 9981da177e4SLinus Torvalds static struct file_operations acpi_processor_power_fops = { 9991da177e4SLinus Torvalds .open = acpi_processor_power_open_fs, 10001da177e4SLinus Torvalds .read = seq_read, 10011da177e4SLinus Torvalds .llseek = seq_lseek, 10021da177e4SLinus Torvalds .release = single_release, 10031da177e4SLinus Torvalds }; 10041da177e4SLinus Torvalds 10054be44fcdSLen Brown int acpi_processor_power_init(struct acpi_processor *pr, 10064be44fcdSLen Brown struct acpi_device *device) 10071da177e4SLinus Torvalds { 10081da177e4SLinus Torvalds acpi_status status = 0; 10091da177e4SLinus Torvalds static int first_run = 0; 10101da177e4SLinus Torvalds struct proc_dir_entry *entry = NULL; 10111da177e4SLinus Torvalds unsigned int i; 10121da177e4SLinus Torvalds 10131da177e4SLinus Torvalds ACPI_FUNCTION_TRACE("acpi_processor_power_init"); 10141da177e4SLinus Torvalds 10151da177e4SLinus Torvalds if (!first_run) { 10161da177e4SLinus Torvalds dmi_check_system(processor_power_dmi_table); 10171da177e4SLinus Torvalds if (max_cstate < ACPI_C_STATES_MAX) 10184be44fcdSLen Brown printk(KERN_NOTICE 10194be44fcdSLen Brown "ACPI: processor limited to max C-state %d\n", 10204be44fcdSLen Brown max_cstate); 10211da177e4SLinus Torvalds first_run++; 10221da177e4SLinus Torvalds } 10231da177e4SLinus Torvalds 102402df8b93SVenkatesh Pallipadi if (!pr) 102502df8b93SVenkatesh Pallipadi return_VALUE(-EINVAL); 102602df8b93SVenkatesh Pallipadi 102702df8b93SVenkatesh Pallipadi if (acpi_fadt.cst_cnt && !nocst) { 10284be44fcdSLen Brown status = 10294be44fcdSLen Brown acpi_os_write_port(acpi_fadt.smi_cmd, acpi_fadt.cst_cnt, 8); 10301da177e4SLinus Torvalds if (ACPI_FAILURE(status)) { 10311da177e4SLinus Torvalds ACPI_DEBUG_PRINT((ACPI_DB_ERROR, 10321da177e4SLinus Torvalds "Notifying BIOS of _CST ability failed\n")); 10331da177e4SLinus Torvalds } 10341da177e4SLinus Torvalds } 10351da177e4SLinus Torvalds 103602df8b93SVenkatesh Pallipadi acpi_processor_power_init_pdc(&(pr->power), pr->id); 103702df8b93SVenkatesh Pallipadi acpi_processor_set_pdc(pr, pr->power.pdc); 10381da177e4SLinus Torvalds acpi_processor_get_power_info(pr); 10391da177e4SLinus Torvalds 10401da177e4SLinus Torvalds /* 10411da177e4SLinus Torvalds * Install the idle handler if processor power management is supported. 10421da177e4SLinus Torvalds * Note that we use previously set idle handler will be used on 10431da177e4SLinus Torvalds * platforms that only support C1. 10441da177e4SLinus Torvalds */ 10451da177e4SLinus Torvalds if ((pr->flags.power) && (!boot_option_idle_override)) { 10461da177e4SLinus Torvalds printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id); 10471da177e4SLinus Torvalds for (i = 1; i <= pr->power.count; i++) 10481da177e4SLinus Torvalds if (pr->power.states[i].valid) 10494be44fcdSLen Brown printk(" C%d[C%d]", i, 10504be44fcdSLen Brown pr->power.states[i].type); 10511da177e4SLinus Torvalds printk(")\n"); 10521da177e4SLinus Torvalds 10531da177e4SLinus Torvalds if (pr->id == 0) { 10541da177e4SLinus Torvalds pm_idle_save = pm_idle; 10551da177e4SLinus Torvalds pm_idle = acpi_processor_idle; 10561da177e4SLinus Torvalds } 10571da177e4SLinus Torvalds } 10581da177e4SLinus Torvalds 10591da177e4SLinus Torvalds /* 'power' [R] */ 10601da177e4SLinus Torvalds entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER, 10611da177e4SLinus Torvalds S_IRUGO, acpi_device_dir(device)); 10621da177e4SLinus Torvalds if (!entry) 10631da177e4SLinus Torvalds ACPI_DEBUG_PRINT((ACPI_DB_ERROR, 10641da177e4SLinus Torvalds "Unable to create '%s' fs entry\n", 10651da177e4SLinus Torvalds ACPI_PROCESSOR_FILE_POWER)); 10661da177e4SLinus Torvalds else { 10671da177e4SLinus Torvalds entry->proc_fops = &acpi_processor_power_fops; 10681da177e4SLinus Torvalds entry->data = acpi_driver_data(device); 10691da177e4SLinus Torvalds entry->owner = THIS_MODULE; 10701da177e4SLinus Torvalds } 10711da177e4SLinus Torvalds 10721da177e4SLinus Torvalds pr->flags.power_setup_done = 1; 10731da177e4SLinus Torvalds 10741da177e4SLinus Torvalds return_VALUE(0); 10751da177e4SLinus Torvalds } 10761da177e4SLinus Torvalds 10774be44fcdSLen Brown int acpi_processor_power_exit(struct acpi_processor *pr, 10784be44fcdSLen Brown struct acpi_device *device) 10791da177e4SLinus Torvalds { 10801da177e4SLinus Torvalds ACPI_FUNCTION_TRACE("acpi_processor_power_exit"); 10811da177e4SLinus Torvalds 10821da177e4SLinus Torvalds pr->flags.power_setup_done = 0; 10831da177e4SLinus Torvalds 10841da177e4SLinus Torvalds if (acpi_device_dir(device)) 10854be44fcdSLen Brown remove_proc_entry(ACPI_PROCESSOR_FILE_POWER, 10864be44fcdSLen Brown acpi_device_dir(device)); 10871da177e4SLinus Torvalds 10881da177e4SLinus Torvalds /* Unregister the idle handler when processor #0 is removed. */ 10891da177e4SLinus Torvalds if (pr->id == 0) { 10901da177e4SLinus Torvalds pm_idle = pm_idle_save; 10911da177e4SLinus Torvalds 10921da177e4SLinus Torvalds /* 10931da177e4SLinus Torvalds * We are about to unload the current idle thread pm callback 10941da177e4SLinus Torvalds * (pm_idle), Wait for all processors to update cached/local 10951da177e4SLinus Torvalds * copies of pm_idle before proceeding. 10961da177e4SLinus Torvalds */ 10971da177e4SLinus Torvalds cpu_idle_wait(); 10981da177e4SLinus Torvalds } 10991da177e4SLinus Torvalds 11001da177e4SLinus Torvalds return_VALUE(0); 11011da177e4SLinus Torvalds } 1102