From 991528d7348667924176f3e29addea0675298944 Mon Sep 17 00:00:00 2001 From: Venkatesh Pallipadi Date: Mon, 25 Sep 2006 16:28:13 -0700 Subject: ACPI: Processor native C-states using MWAIT Intel processors starting with the Core Duo support support processor native C-state using the MWAIT instruction. Refer: Intel Architecture Software Developer's Manual http://www.intel.com/design/Pentium4/manuals/253668.htm Platform firmware exports the support for Native C-state to OS using ACPI _PDC and _CST methods. Refer: Intel Processor Vendor-Specific ACPI: Interface Specification http://www.intel.com/technology/iapc/acpi/downloads/302223.htm With Processor Native C-state, we use 'MWAIT' instruction on the processor to enter different C-states (C1, C2, C3). We won't use the special IO ports to enter C-state and no SMM mode etc required to enter C-state. Overall this will mean better C-state support. One major advantage of using MWAIT for all C-states is, with this and "treat interrupt as break event" feature of MWAIT, we can now get accurate timing for the time spent in C1, C2, .. states. Signed-off-by: Venkatesh Pallipadi Signed-off-by: Andrew Morton Signed-off-by: Len Brown --- drivers/acpi/processor_idle.c | 101 ++++++++++++++++++++++++++---------------- 1 file changed, 63 insertions(+), 38 deletions(-) (limited to 'drivers/acpi') diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 0a395fca843..429a39dbd75 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -219,6 +219,23 @@ static void acpi_safe_halt(void) 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_fadt.xpm_tmr_blk.address); + } +} + static void acpi_processor_idle(void) { struct acpi_processor *pr = NULL; @@ -361,11 +378,7 @@ static void acpi_processor_idle(void) /* Get start time (ticks) */ t1 = inl(acpi_fadt.xpm_tmr_blk.address); /* Invoke C2 */ - inb(cx->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. */ - t2 = inl(acpi_fadt.xpm_tmr_blk.address); + acpi_cstate_enter(cx); /* Get end time (ticks) */ t2 = inl(acpi_fadt.xpm_tmr_blk.address); @@ -401,9 +414,7 @@ static void acpi_processor_idle(void) /* Get start time (ticks) */ t1 = inl(acpi_fadt.xpm_tmr_blk.address); /* Invoke C3 */ - inb(cx->address); - /* Dummy wait op (see above) */ - t2 = inl(acpi_fadt.xpm_tmr_blk.address); + acpi_cstate_enter(cx); /* Get end time (ticks) */ t2 = inl(acpi_fadt.xpm_tmr_blk.address); if (pr->flags.bm_check) { @@ -628,20 +639,16 @@ static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr) return 0; } -static int acpi_processor_get_power_info_default_c1(struct acpi_processor *pr) +static int acpi_processor_get_power_info_default(struct acpi_processor *pr) { - - /* Zero initialize all the C-states info. */ - memset(pr->power.states, 0, sizeof(pr->power.states)); - - /* set the first C-State to C1 */ - pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1; - - /* the C0 state only exists as a filler in our array, - * and all processors need to support C1 */ + 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; - pr->power.states[ACPI_STATE_C1].valid = 1; - return 0; } @@ -658,12 +665,7 @@ static int acpi_processor_get_power_info_cst(struct acpi_processor *pr) if (nocst) return -ENODEV; - current_count = 1; - - /* Zero initialize C2 onwards and prepare for fresh CST lookup */ - for (i = 2; i < ACPI_PROCESSOR_MAX_POWER; i++) - memset(&(pr->power.states[i]), 0, - sizeof(struct acpi_processor_cx)); + current_count = 0; status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer); if (ACPI_FAILURE(status)) { @@ -718,22 +720,39 @@ static int acpi_processor_get_power_info_cst(struct acpi_processor *pr) (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)) continue; - cx.address = (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) ? - 0 : reg->address; - /* There should be an easy way to extract an integer... */ obj = (union acpi_object *)&(element->package.elements[1]); if (obj->type != ACPI_TYPE_INTEGER) continue; cx.type = obj->integer.value; - - if ((cx.type != ACPI_STATE_C1) && - (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO)) - continue; - - if ((cx.type < ACPI_STATE_C2) || (cx.type > ACPI_STATE_C3)) - continue; + /* + * 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 = (union acpi_object *)&(element->package.elements[2]); if (obj->type != ACPI_TYPE_INTEGER) @@ -938,12 +957,18 @@ static int acpi_processor_get_power_info(struct acpi_processor *pr) /* NOTE: the idle thread may not be running while calling * this function */ - /* Adding C1 state */ - acpi_processor_get_power_info_default_c1(pr); + /* 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) 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); /* -- cgit v1.2.3