/* * processor_idle - idle state submodule to the ACPI processor driver * * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com> * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com> * Copyright (C) 2004, 2005 Dominik Brodowski <linux@brodo.de> * Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> * - Added processor hotplug support * Copyright (C) 2005 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> * - Added support for C3 on SMP * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or (at * your option) any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/cpufreq.h> #include <linux/proc_fs.h> #include <linux/seq_file.h> #include <linux/acpi.h> #include <linux/dmi.h> #include <linux/moduleparam.h> #include <linux/sched.h> /* need_resched() */ #include <linux/latency.h> #include <linux/clockchips.h> /* * Include the apic definitions for x86 to have the APIC timer related defines * available also for UP (on SMP it gets magically included via linux/smp.h). * asm/acpi.h is not an option, as it would require more include magic. Also * creating an empty asm-ia64/apic.h would just trade pest vs. cholera. */ #ifdef CONFIG_X86 #include <asm/apic.h> #endif #include <asm/io.h> #include <asm/uaccess.h> #include <acpi/acpi_bus.h> #include <acpi/processor.h> #define ACPI_PROCESSOR_COMPONENT 0x01000000 #define ACPI_PROCESSOR_CLASS "processor" #define _COMPONENT ACPI_PROCESSOR_COMPONENT ACPI_MODULE_NAME("processor_idle"); #define ACPI_PROCESSOR_FILE_POWER "power" #define US_TO_PM_TIMER_TICKS(t) ((t * (PM_TIMER_FREQUENCY/1000)) / 1000) #define C2_OVERHEAD 4 /* 1us (3.579 ticks per us) */ #define C3_OVERHEAD 4 /* 1us (3.579 ticks per us) */ static void (*pm_idle_save) (void) __read_mostly; module_param(max_cstate, uint, 0644); static unsigned int nocst __read_mostly; module_param(nocst, uint, 0000); /* * bm_history -- bit-mask with a bit per jiffy of bus-master activity * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms * 100 HZ: 0x0000000F: 4 jiffies = 40ms * reduce history for more aggressive entry into C3 */ static unsigned int bm_history __read_mostly = (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1)); module_param(bm_history, uint, 0644); /* -------------------------------------------------------------------------- Power Management -------------------------------------------------------------------------- */ /* * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3. * For now disable this. Probably a bug somewhere else. * * To skip this limit, boot/load with a large max_cstate limit. */ static int set_max_cstate(struct dmi_system_id *id) { if (max_cstate > ACPI_PROCESSOR_MAX_POWER) return 0; printk(KERN_NOTICE PREFIX "%s detected - limiting to C%ld max_cstate." " Override with \"processor.max_cstate=%d\"\n", id->ident, (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1); max_cstate = (long)id->driver_data; return 0; } /* Actually this shouldn't be __cpuinitdata, would be better to fix the callers to only run once -AK */ static struct dmi_system_id __cpuinitdata processor_power_dmi_table[] = { { set_max_cstate, "IBM ThinkPad R40e", { DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), DMI_MATCH(DMI_BIOS_VERSION,"1SET70WW")}, (void *)1}, { set_max_cstate, "IBM ThinkPad R40e", { DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW")}, (void *)1}, { set_max_cstate, "IBM ThinkPad R40e", { DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), DMI_MATCH(DMI_BIOS_VERSION,"1SET43WW") }, (void*)1}, { set_max_cstate, "IBM ThinkPad R40e", { DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), DMI_MATCH(DMI_BIOS_VERSION,"1SET45WW") }, (void*)1}, { set_max_cstate, "IBM ThinkPad R40e", { DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), DMI_MATCH(DMI_BIOS_VERSION,"1SET47WW") }, (void*)1}, { set_max_cstate, "IBM ThinkPad R40e", { DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), DMI_MATCH(DMI_BIOS_VERSION,"1SET50WW") }, (void*)1}, { set_max_cstate, "IBM ThinkPad R40e", { DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), DMI_MATCH(DMI_BIOS_VERSION,"1SET52WW") }, (void*)1}, { set_max_cstate, "IBM ThinkPad R40e", { DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), DMI_MATCH(DMI_BIOS_VERSION,"1SET55WW") }, (void*)1}, { set_max_cstate, "IBM ThinkPad R40e", { DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), DMI_MATCH(DMI_BIOS_VERSION,"1SET56WW") }, (void*)1}, { set_max_cstate, "IBM ThinkPad R40e", { DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), DMI_MATCH(DMI_BIOS_VERSION,"1SET59WW") }, (void*)1}, { set_max_cstate, "IBM ThinkPad R40e", { DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW") }, (void*)1}, { set_max_cstate, "IBM ThinkPad R40e", { DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), DMI_MATCH(DMI_BIOS_VERSION,"1SET61WW") }, (void*)1}, { set_max_cstate, "IBM ThinkPad R40e", { DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), DMI_MATCH(DMI_BIOS_VERSION,"1SET62WW") }, (void*)1}, { set_max_cstate, "IBM ThinkPad R40e", { DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), DMI_MATCH(DMI_BIOS_VERSION,"1SET64WW") }, (void*)1}, { set_max_cstate, "IBM ThinkPad R40e", { DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), DMI_MATCH(DMI_BIOS_VERSION,"1SET65WW") }, (void*)1}, { set_max_cstate, "IBM ThinkPad R40e", { DMI_MATCH(DMI_BIOS_VENDOR,"IBM"), DMI_MATCH(DMI_BIOS_VERSION,"1SET68WW") }, (void*)1}, { set_max_cstate, "Medion 41700", { DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"), DMI_MATCH(DMI_BIOS_VERSION,"R01-A1J")}, (void *)1}, { set_max_cstate, "Clevo 5600D", { DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"), DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")}, (void *)2}, {}, }; static inline u32 ticks_elapsed(u32 t1, u32 t2) { if (t2 >= t1) return (t2 - t1); else if (!(acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER)) return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF); else return ((0xFFFFFFFF - t1) + t2); } static void acpi_processor_power_activate(struct acpi_processor *pr, struct acpi_processor_cx *new) { struct acpi_processor_cx *old; if (!pr || !new) return; old = pr->power.state; if (old) old->promotion.count = 0; new->demotion.count = 0; /* Cleanup from old state. */ if (old) { switch (old->type) { case ACPI_STATE_C3: /* Disable bus master reload */ if (new->type != ACPI_STATE_C3 && pr->flags.bm_check) acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0); break; } } /* Prepare to use new state. */ switch (new->type) { case ACPI_STATE_C3: /* Enable bus master reload */ if (old->type != ACPI_STATE_C3 && pr->flags.bm_check) acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1); break; } pr->power.state = new; return; } static void acpi_safe_halt(void) { current_thread_info()->status &= ~TS_POLLING; /* * TS_POLLING-cleared state must be visible before we * test NEED_RESCHED: */ smp_mb(); if (!need_resched()) safe_halt(); current_thread_info()->status |= TS_POLLING; } static atomic_t c3_cpu_count; /* Common C-state entry for C2, C3, .. */ static void acpi_cstate_enter(struct acpi_processor_cx *cstate) { if (cstate->space_id == ACPI_CSTATE_FFH) { /* Call into architectural FFH based C-state */ acpi_processor_ffh_cstate_enter(cstate); } else { int unused; /* IO port based C-state */ inb(cstate->address); /* Dummy wait op - must do something useless after P_LVL2 read because chipsets cannot guarantee that STPCLK# signal gets asserted in time to freeze execution properly. */ unused = inl(acpi_gbl_FADT.xpm_timer_block.address); } } #ifdef ARCH_APICTIMER_STOPS_ON_C3 /* * Some BIOS implementations switch to C3 in the published C2 state. * This seems to be a common problem on AMD boxen, but other vendors * are affected too. We pick the most conservative approach: we assume * that the local APIC stops in both C2 and C3. */ static void acpi_timer_check_state(int state, struct acpi_processor *pr, struct acpi_processor_cx *cx) { struct acpi_processor_power *pwr = &pr->power; u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2; /* * Check, if one of the previous states already marked the lapic * unstable */ if (pwr->timer_broadcast_on_state < state) return; if (cx->type >= type) pr->power.timer_broadcast_on_state = state; } static void acpi_propagate_timer_broadcast(struct acpi_processor *pr) { #ifdef CONFIG_GENERIC_CLOCKEVENTS unsigned long reason; reason = pr->power.timer_broadcast_on_state < INT_MAX ? CLOCK_EVT_NOTIFY_BROADCAST_ON : CLOCK_EVT_NOTIFY_BROADCAST_OFF; clockevents_notify(reason, &pr->id); #else cpumask_t mask = cpumask_of_cpu(pr->id); if (pr->power.timer_broadcast_on_state < INT_MAX) on_each_cpu(switch_APIC_timer_to_ipi, &mask, 1, 1); else on_each_cpu(switch_ipi_to_APIC_timer, &mask, 1, 1); #endif } /* Power(C) State timer broadcast control */ static void acpi_state_timer_broadcast(struct acpi_processor *pr, struct acpi_processor_cx *cx, int broadcast) { #ifdef CONFIG_GENERIC_CLOCKEVENTS int state = cx - pr->power.states; if (state >= pr->power.timer_broadcast_on_state) { unsigned long reason; reason = broadcast ? CLOCK_EVT_NOTIFY_BROADCAST_ENTER : CLOCK_EVT_NOTIFY_BROADCAST_EXIT; clockevents_notify(reason, &pr->id); } #endif } #else static void acpi_timer_check_state(int state, struct acpi_processor *pr, struct acpi_processor_cx *cstate) { } static void acpi_propagate_timer_broadcast(struct acpi_processor *pr) { } static void acpi_state_timer_broadcast(struct acpi_processor *pr, struct acpi_processor_cx *cx, int broadcast) { } #endif static void acpi_processor_idle(void) { struct acpi_processor *pr = NULL; struct acpi_processor_cx *cx = NULL; struct acpi_processor_cx *next_state = NULL; int sleep_ticks = 0; u32 t1, t2 = 0; /* * Interrupts must be disabled during bus mastering calculations and * for C2/C3 transitions. */ local_irq_disable(); pr = processors[smp_processor_id()]; if (!pr) { local_irq_enable(); return; } /* * Check whether we truly need to go idle, or should * reschedule: */ if (unlikely(need_resched())) { local_irq_enable(); return; } cx = pr->power.state; if (!cx) { if (pm_idle_save) pm_idle_save(); else acpi_safe_halt(); return; } /* * Check BM Activity * ----------------- * Check for bus mastering activity (if required), record, and check * for demotion. */ if (pr->flags.bm_check) { u32 bm_status = 0; unsigned long diff = jiffies - pr->power.bm_check_timestamp; if (diff > 31) diff = 31; pr->power.bm_activity <<= diff; acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status); if (bm_status) { pr->power.bm_activity |= 0x1; acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1); } /* * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect * the true state of bus mastering activity; forcing us to * manually check the BMIDEA bit of each IDE channel. */ else if (errata.piix4.bmisx) { if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01) || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01)) pr->power.bm_activity |= 0x1; } pr->power.bm_check_timestamp = jiffies; /* * If bus mastering is or was active this jiffy, demote * to avoid a faulty transition. Note that the processor * won't enter a low-power state during this call (to this * function) but should upon the next. * * TBD: A better policy might be to fallback to the demotion * state (use it for this quantum only) istead of * demoting -- and rely on duration as our sole demotion * qualification. This may, however, introduce DMA * issues (e.g. floppy DMA transfer overrun/underrun). */ if ((pr->power.bm_activity & 0x1) && cx->demotion.threshold.bm) { local_irq_enable(); next_state = cx->demotion.state; goto end; } } #ifdef CONFIG_HOTPLUG_CPU /* * Check for P_LVL2_UP flag before entering C2 and above on * an SMP system. We do it here instead of doing it at _CST/P_LVL * detection phase, to work cleanly with logical CPU hotplug. */ if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) && !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED)) cx = &pr->power.states[ACPI_STATE_C1]; #endif /* * Sleep: * ------ * Invoke the current Cx state to put the processor to sleep. */ if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) { current_thread_info()->status &= ~TS_POLLING; /* * TS_POLLING-cleared state must be visible before we * test NEED_RESCHED: */ smp_mb(); if (need_resched()) { current_thread_info()->status |= TS_POLLING; local_irq_enable(); return; } } switch (cx->type) { case ACPI_STATE_C1: /* * Invoke C1. * Use the appropriate idle routine, the one that would * be used without acpi C-states. */ if (pm_idle_save) pm_idle_save(); else acpi_safe_halt(); /* * TBD: Can't get time duration while in C1, as resumes * go to an ISR rather than here. Need to instrument * base interrupt handler. */ sleep_ticks = 0xFFFFFFFF; break; case ACPI_STATE_C2: /* Get start time (ticks) */ t1 = inl(acpi_gbl_FADT.xpm_timer_block.address); /* Invoke C2 */ acpi_state_timer_broadcast(pr, cx, 1); acpi_cstate_enter(cx); /* Get end time (ticks) */ t2 = inl(acpi_gbl_FADT.xpm_timer_block.address); #ifdef CONFIG_GENERIC_TIME /* TSC halts in C2, so notify users */ mark_tsc_unstable("possible TSC halt in C2"); #endif /* Re-enable interrupts */ local_irq_enable(); current_thread_info()->status |= TS_POLLING; /* Compute time (ticks) that we were actually asleep */ sleep_ticks = ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD; acpi_state_timer_broadcast(pr, cx, 0); break; case ACPI_STATE_C3: if (pr->flags.bm_check) { if (atomic_inc_return(&c3_cpu_count) == num_online_cpus()) { /* * All CPUs are trying to go to C3 * Disable bus master arbitration */ acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1); } } else { /* SMP with no shared cache... Invalidate cache */ ACPI_FLUSH_CPU_CACHE(); } /* Get start time (ticks) */ t1 = inl(acpi_gbl_FADT.xpm_timer_block.address); /* Invoke C3 */ acpi_state_timer_broadcast(pr, cx, 1); acpi_cstate_enter(cx); /* Get end time (ticks) */ t2 = inl(acpi_gbl_FADT.xpm_timer_block.address); if (pr->flags.bm_check) { /* Enable bus master arbitration */ atomic_dec(&c3_cpu_count); acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0); } #ifdef CONFIG_GENERIC_TIME /* TSC halts in C3, so notify users */ mark_tsc_unstable("TSC halts in C3"); #endif /* Re-enable interrupts */ local_irq_enable(); current_thread_info()->status |= TS_POLLING; /* Compute time (ticks) that we were actually asleep */ sleep_ticks = ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD; acpi_state_timer_broadcast(pr, cx, 0); break; default: local_irq_enable(); return; } cx->usage++; if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0)) cx->time += sleep_ticks; next_state = pr->power.state; #ifdef CONFIG_HOTPLUG_CPU /* Don't do promotion/demotion */ if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) && !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED)) { next_state = cx; goto end; } #endif /* * Promotion? * ---------- * Track the number of longs (time asleep is greater than threshold) * and promote when the count threshold is reached. Note that bus * mastering activity may prevent promotions. * Do not promote above max_cstate. */ if (cx->promotion.state && ((cx->promotion.state - pr->power.states) <= max_cstate)) { if (sleep_ticks > cx->promotion.threshold.ticks && cx->promotion.state->latency <= system_latency_constraint()) { cx->promotion.count++; cx->demotion.count = 0; if (cx->promotion.count >= cx->promotion.threshold.count) { if (pr->flags.bm_check) { if (! (pr->power.bm_activity & cx-> promotion.threshold.bm)) { next_state = cx->promotion.state; goto end; } } else { next_state = cx->promotion.state; goto end; } } } } /* * Demotion? * --------- * Track the number of shorts (time asleep is less than time threshold) * and demote when the usage threshold is reached. */ if (cx->demotion.state) { if (sleep_ticks < cx->demotion.threshold.ticks) { cx->demotion.count++; cx->promotion.count = 0; if (cx->demotion.count >= cx->demotion.threshold.count) { next_state = cx->demotion.state; goto end; } } } end: /* * Demote if current state exceeds max_cstate * or if the latency of the current state is unacceptable */ if ((pr->power.state - pr->power.states) > max_cstate || pr->power.state->latency > system_latency_constraint()) { if (cx->demotion.state) next_state = cx->demotion.state; } /* * New Cx State? * ------------- * If we're going to start using a new Cx state we must clean up * from the previous and prepare to use the new. */ if (next_state != pr->power.state) acpi_processor_power_activate(pr, next_state); } static int acpi_processor_set_power_policy(struct acpi_processor *pr) { unsigned int i; unsigned int state_is_set = 0; struct acpi_processor_cx *lower = NULL; struct acpi_processor_cx *higher = NULL; struct acpi_processor_cx *cx; if (!pr) return -EINVAL; /* * This function sets the default Cx state policy (OS idle handler). * Our scheme is to promote quickly to C2 but more conservatively * to C3. We're favoring C2 for its characteristics of low latency * (quick response), good power savings, and ability to allow bus * mastering activity. Note that the Cx state policy is completely * customizable and can be altered dynamically. */ /* startup state */ for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { cx = &pr->power.states[i]; if (!cx->valid) continue; if (!state_is_set) pr->power.state = cx; state_is_set++; break; } if (!state_is_set) return -ENODEV; /* demotion */ for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { cx = &pr->power.states[i]; if (!cx->valid) continue; if (lower) { cx->demotion.state = lower; cx->demotion.threshold.ticks = cx->latency_ticks; cx->demotion.threshold.count = 1; if (cx->type == ACPI_STATE_C3) cx->demotion.threshold.bm = bm_history; } lower = cx; } /* promotion */ for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) { cx = &pr->power.states[i]; if (!cx->valid) continue; if (higher) { cx->promotion.state = higher; cx->promotion.threshold.ticks = cx->latency_ticks; if (cx->type >= ACPI_STATE_C2) cx->promotion.threshold.count = 4; else cx->promotion.threshold.count = 10; if (higher->type == ACPI_STATE_C3) cx->promotion.threshold.bm = bm_history; } higher = cx; } return 0; } static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr) { if (!pr) return -EINVAL; if (!pr->pblk) return -ENODEV; /* if info is obtained from pblk/fadt, type equals state */ pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2; pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3; #ifndef CONFIG_HOTPLUG_CPU /* * Check for P_LVL2_UP flag before entering C2 and above on * an SMP system. */ if ((num_online_cpus() > 1) && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED)) return -ENODEV; #endif /* determine C2 and C3 address from pblk */ pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4; pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5; /* determine latencies from FADT */ pr->power.states[ACPI_STATE_C2].latency = acpi_gbl_FADT.C2latency; pr->power.states[ACPI_STATE_C3].latency = acpi_gbl_FADT.C3latency; ACPI_DEBUG_PRINT((ACPI_DB_INFO, "lvl2[0x%08x] lvl3[0x%08x]\n", pr->power.states[ACPI_STATE_C2].address, pr->power.states[ACPI_STATE_C3].address)); return 0; } static int acpi_processor_get_power_info_default(struct acpi_processor *pr) { if (!pr->power.states[ACPI_STATE_C1].valid) { /* set the first C-State to C1 */ /* all processors need to support C1 */ pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1; pr->power.states[ACPI_STATE_C1].valid = 1; } /* the C0 state only exists as a filler in our array */ pr->power.states[ACPI_STATE_C0].valid = 1; return 0; } static int acpi_processor_get_power_info_cst(struct acpi_processor *pr) { acpi_status status = 0; acpi_integer count; int current_count; int i; struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; union acpi_object *cst; if (nocst) return -ENODEV; current_count = 0; status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer); if (ACPI_FAILURE(status)) { ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n")); return -ENODEV; } cst = buffer.pointer; /* There must be at least 2 elements */ if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) { printk(KERN_ERR PREFIX "not enough elements in _CST\n"); status = -EFAULT; goto end; } count = cst->package.elements[0].integer.value; /* Validate number of power states. */ if (count < 1 || count != cst->package.count - 1) { printk(KERN_ERR PREFIX "count given by _CST is not valid\n"); status = -EFAULT; goto end; } /* Tell driver that at least _CST is supported. */ pr->flags.has_cst = 1; for (i = 1; i <= count; i++) { union acpi_object *element; union acpi_object *obj; struct acpi_power_register *reg; struct acpi_processor_cx cx; memset(&cx, 0, sizeof(cx)); element = &(cst->package.elements[i]); if (element->type != ACPI_TYPE_PACKAGE) continue; if (element->package.count != 4) continue; obj = &(element->package.elements[0]); if (obj->type != ACPI_TYPE_BUFFER) continue; reg = (struct acpi_power_register *)obj->buffer.pointer; if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO && (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)) continue; /* There should be an easy way to extract an integer... */ obj = &(element->package.elements[1]); if (obj->type != ACPI_TYPE_INTEGER) continue; cx.type = obj->integer.value; /* * Some buggy BIOSes won't list C1 in _CST - * Let acpi_processor_get_power_info_default() handle them later */ if (i == 1 && cx.type != ACPI_STATE_C1) current_count++; cx.address = reg->address; cx.index = current_count + 1; cx.space_id = ACPI_CSTATE_SYSTEMIO; if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) { if (acpi_processor_ffh_cstate_probe (pr->id, &cx, reg) == 0) { cx.space_id = ACPI_CSTATE_FFH; } else if (cx.type != ACPI_STATE_C1) { /* * C1 is a special case where FIXED_HARDWARE * can be handled in non-MWAIT way as well. * In that case, save this _CST entry info. * That is, we retain space_id of SYSTEM_IO for * halt based C1. * Otherwise, ignore this info and continue. */ continue; } } obj = &(element->package.elements[2]); if (obj->type != ACPI_TYPE_INTEGER) continue; cx.latency = obj->integer.value; obj = &(element->package.elements[3]); if (obj->type != ACPI_TYPE_INTEGER) continue; cx.power = obj->integer.value; current_count++; memcpy(&(pr->power.states[current_count]), &cx, sizeof(cx)); /* * We support total ACPI_PROCESSOR_MAX_POWER - 1 * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1) */ if (current_count >= (ACPI_PROCESSOR_MAX_POWER - 1)) { printk(KERN_WARNING "Limiting number of power states to max (%d)\n", ACPI_PROCESSOR_MAX_POWER); printk(KERN_WARNING "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n"); break; } } ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n", current_count)); /* Validate number of power states discovered */ if (current_count < 2) status = -EFAULT; end: kfree(buffer.pointer); return status; } static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx) { if (!cx->address) return; /* * C2 latency must be less than or equal to 100 * microseconds. */ else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) { ACPI_DEBUG_PRINT((ACPI_DB_INFO, "latency too large [%d]\n", cx->latency)); return; } /* * Otherwise we've met all of our C2 requirements. * Normalize the C2 latency to expidite policy */ cx->valid = 1; cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency); return; } static void acpi_processor_power_verify_c3(struct acpi_processor *pr, struct acpi_processor_cx *cx) { static int bm_check_flag; if (!cx->address) return; /* * C3 latency must be less than or equal to 1000 * microseconds. */ else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) { ACPI_DEBUG_PRINT((ACPI_DB_INFO, "latency too large [%d]\n", cx->latency)); return; } /* * PIIX4 Erratum #18: We don't support C3 when Type-F (fast) * DMA transfers are used by any ISA device to avoid livelock. * Note that we could disable Type-F DMA (as recommended by * the erratum), but this is known to disrupt certain ISA * devices thus we take the conservative approach. */ else if (errata.piix4.fdma) { ACPI_DEBUG_PRINT((ACPI_DB_INFO, "C3 not supported on PIIX4 with Type-F DMA\n")); return; } /* All the logic here assumes flags.bm_check is same across all CPUs */ if (!bm_check_flag) { /* Determine whether bm_check is needed based on CPU */ acpi_processor_power_init_bm_check(&(pr->flags), pr->id); bm_check_flag = pr->flags.bm_check; } else { pr->flags.bm_check = bm_check_flag; } if (pr->flags.bm_check) { /* bus mastering control is necessary */ if (!pr->flags.bm_control) { ACPI_DEBUG_PRINT((ACPI_DB_INFO, "C3 support requires bus mastering control\n")); return; } } else { /* * WBINVD should be set in fadt, for C3 state to be * supported on when bm_check is not required. */ if (!(acpi_gbl_FADT.flags & ACPI_FADT_WBINVD)) { ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Cache invalidation should work properly" " for C3 to be enabled on SMP systems\n")); return; } acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0); } /* * Otherwise we've met all of our C3 requirements. * Normalize the C3 latency to expidite policy. Enable * checking of bus mastering status (bm_check) so we can * use this in our C3 policy */ cx->valid = 1; cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency); return; } static int acpi_processor_power_verify(struct acpi_processor *pr) { unsigned int i; unsigned int working = 0; pr->power.timer_broadcast_on_state = INT_MAX; for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { struct acpi_processor_cx *cx = &pr->power.states[i]; switch (cx->type) { case ACPI_STATE_C1: cx->valid = 1; break; case ACPI_STATE_C2: acpi_processor_power_verify_c2(cx); if (cx->valid) acpi_timer_check_state(i, pr, cx); break; case ACPI_STATE_C3: acpi_processor_power_verify_c3(pr, cx); if (cx->valid) acpi_timer_check_state(i, pr, cx); break; } if (cx->valid) working++; } acpi_propagate_timer_broadcast(pr); return (working); } static int acpi_processor_get_power_info(struct acpi_processor *pr) { unsigned int i; int result; /* NOTE: the idle thread may not be running while calling * this function */ /* Zero initialize all the C-states info. */ memset(pr->power.states, 0, sizeof(pr->power.states)); result = acpi_processor_get_power_info_cst(pr); if (result == -ENODEV) result = acpi_processor_get_power_info_fadt(pr); if (result) return result; acpi_processor_get_power_info_default(pr); pr->power.count = acpi_processor_power_verify(pr); /* * Set Default Policy * ------------------ * Now that we know which states are supported, set the default * policy. Note that this policy can be changed dynamically * (e.g. encourage deeper sleeps to conserve battery life when * not on AC). */ result = acpi_processor_set_power_policy(pr); if (result) return result; /* * if one state of type C2 or C3 is available, mark this * CPU as being "idle manageable" */ for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { if (pr->power.states[i].valid) { pr->power.count = i; if (pr->power.states[i].type >= ACPI_STATE_C2) pr->flags.power = 1; } } return 0; } int acpi_processor_cst_has_changed(struct acpi_processor *pr) { int result = 0; if (!pr) return -EINVAL; if (nocst) { return -ENODEV; } if (!pr->flags.power_setup_done) return -ENODEV; /* Fall back to the default idle loop */ pm_idle = pm_idle_save; synchronize_sched(); /* Relies on interrupts forcing exit from idle. */ pr->flags.power = 0; result = acpi_processor_get_power_info(pr); if ((pr->flags.power == 1) && (pr->flags.power_setup_done)) pm_idle = acpi_processor_idle; return result; } /* proc interface */ static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset) { struct acpi_processor *pr = seq->private; unsigned int i; if (!pr) goto end; seq_printf(seq, "active state: C%zd\n" "max_cstate: C%d\n" "bus master activity: %08x\n" "maximum allowed latency: %d usec\n", pr->power.state ? pr->power.state - pr->power.states : 0, max_cstate, (unsigned)pr->power.bm_activity, system_latency_constraint()); seq_puts(seq, "states:\n"); for (i = 1; i <= pr->power.count; i++) { seq_printf(seq, " %cC%d: ", (&pr->power.states[i] == pr->power.state ? '*' : ' '), i); if (!pr->power.states[i].valid) { seq_puts(seq, "<not supported>\n"); continue; } switch (pr->power.states[i].type) { case ACPI_STATE_C1: seq_printf(seq, "type[C1] "); break; case ACPI_STATE_C2: seq_printf(seq, "type[C2] "); break; case ACPI_STATE_C3: seq_printf(seq, "type[C3] "); break; default: seq_printf(seq, "type[--] "); break; } if (pr->power.states[i].promotion.state) seq_printf(seq, "promotion[C%zd] ", (pr->power.states[i].promotion.state - pr->power.states)); else seq_puts(seq, "promotion[--] "); if (pr->power.states[i].demotion.state) seq_printf(seq, "demotion[C%zd] ", (pr->power.states[i].demotion.state - pr->power.states)); else seq_puts(seq, "demotion[--] "); seq_printf(seq, "latency[%03d] usage[%08d] duration[%020llu]\n", pr->power.states[i].latency, pr->power.states[i].usage, (unsigned long long)pr->power.states[i].time); } end: return 0; } static int acpi_processor_power_open_fs(struct inode *inode, struct file *file) { return single_open(file, acpi_processor_power_seq_show, PDE(inode)->data); } static const struct file_operations acpi_processor_power_fops = { .open = acpi_processor_power_open_fs, .read = seq_read, .llseek = seq_lseek, .release = single_release, }; #ifdef CONFIG_SMP static void smp_callback(void *v) { /* we already woke the CPU up, nothing more to do */ } /* * This function gets called when a part of the kernel has a new latency * requirement. This means we need to get all processors out of their C-state, * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that * wakes them all right up. */ static int acpi_processor_latency_notify(struct notifier_block *b, unsigned long l, void *v) { smp_call_function(smp_callback, NULL, 0, 1); return NOTIFY_OK; } static struct notifier_block acpi_processor_latency_notifier = { .notifier_call = acpi_processor_latency_notify, }; #endif int __cpuinit acpi_processor_power_init(struct acpi_processor *pr, struct acpi_device *device) { acpi_status status = 0; static int first_run; struct proc_dir_entry *entry = NULL; unsigned int i; if (!first_run) { dmi_check_system(processor_power_dmi_table); if (max_cstate < ACPI_C_STATES_MAX) printk(KERN_NOTICE "ACPI: processor limited to max C-state %d\n", max_cstate); first_run++; #ifdef CONFIG_SMP register_latency_notifier(&acpi_processor_latency_notifier); #endif } if (!pr) return -EINVAL; if (acpi_gbl_FADT.cst_control && !nocst) { status = acpi_os_write_port(acpi_gbl_FADT.smi_command, acpi_gbl_FADT.cst_control, 8); if (ACPI_FAILURE(status)) { ACPI_EXCEPTION((AE_INFO, status, "Notifying BIOS of _CST ability failed")); } } acpi_processor_get_power_info(pr); /* * Install the idle handler if processor power management is supported. * Note that we use previously set idle handler will be used on * platforms that only support C1. */ if ((pr->flags.power) && (!boot_option_idle_override)) { printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id); for (i = 1; i <= pr->power.count; i++) if (pr->power.states[i].valid) printk(" C%d[C%d]", i, pr->power.states[i].type); printk(")\n"); if (pr->id == 0) { pm_idle_save = pm_idle; pm_idle = acpi_processor_idle; } } /* 'power' [R] */ entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER, S_IRUGO, acpi_device_dir(device)); if (!entry) return -EIO; else { entry->proc_fops = &acpi_processor_power_fops; entry->data = acpi_driver_data(device); entry->owner = THIS_MODULE; } pr->flags.power_setup_done = 1; return 0; } int acpi_processor_power_exit(struct acpi_processor *pr, struct acpi_device *device) { pr->flags.power_setup_done = 0; if (acpi_device_dir(device)) remove_proc_entry(ACPI_PROCESSOR_FILE_POWER, acpi_device_dir(device)); /* Unregister the idle handler when processor #0 is removed. */ if (pr->id == 0) { pm_idle = pm_idle_save; /* * We are about to unload the current idle thread pm callback * (pm_idle), Wait for all processors to update cached/local * copies of pm_idle before proceeding. */ cpu_idle_wait(); #ifdef CONFIG_SMP unregister_latency_notifier(&acpi_processor_latency_notifier); #endif } return 0; }