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linux/drivers/acpi/processor_idle.c
Ingo Molnar 39c715b717 [PATCH] smp_processor_id() cleanup 
This patch implements a number of smp_processor_id() cleanup ideas that
Arjan van de Ven and I came up with.

The previous __smp_processor_id/_smp_processor_id/smp_processor_id API
spaghetti was hard to follow both on the implementational and on the
usage side.

Some of the complexity arose from picking wrong names, some of the
complexity comes from the fact that not all architectures defined
__smp_processor_id.

In the new code, there are two externally visible symbols:

 - smp_processor_id(): debug variant.

 - raw_smp_processor_id(): nondebug variant. Replaces all existing
   uses of _smp_processor_id() and __smp_processor_id(). Defined
   by every SMP architecture in include/asm-*/smp.h.

There is one new internal symbol, dependent on DEBUG_PREEMPT:

 - debug_smp_processor_id(): internal debug variant, mapped to
                             smp_processor_id().

Also, i moved debug_smp_processor_id() from lib/kernel_lock.c into a new
lib/smp_processor_id.c file.  All related comments got updated and/or
clarified.

I have build/boot tested the following 8 .config combinations on x86:

 {SMP,UP} x {PREEMPT,!PREEMPT} x {DEBUG_PREEMPT,!DEBUG_PREEMPT}

I have also build/boot tested x64 on UP/PREEMPT/DEBUG_PREEMPT.  (Other
architectures are untested, but should work just fine.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-21 18:46:13 -07:00

1018 lines
26 KiB
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/*
* 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 Dominik Brodowski <linux@brodo.de>
* Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
* - Added processor hotplug support
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* 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 <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 ACPI_PROCESSOR_DRIVER_NAME "ACPI Processor Driver"
#define _COMPONENT ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME ("acpi_processor")
#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);
module_param(max_cstate, uint, 0644);
static unsigned int nocst = 0;
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 = (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 no_c2c3(struct dmi_system_id *id)
{
if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
return 0;
printk(KERN_NOTICE PREFIX "%s detected - C2,C3 disabled."
" Override with \"processor.max_cstate=%d\"\n", id->ident,
ACPI_PROCESSOR_MAX_POWER + 1);
max_cstate = 1;
return 0;
}
static struct dmi_system_id __initdata processor_power_dmi_table[] = {
{ no_c2c3, "IBM ThinkPad R40e", {
DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW") }},
{ no_c2c3, "Medion 41700", {
DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
DMI_MATCH(DMI_BIOS_VERSION,"R01-A1J") }},
{},
};
static inline u32
ticks_elapsed (
u32 t1,
u32 t2)
{
if (t2 >= t1)
return (t2 - t1);
else if (!acpi_fadt.tmr_val_ext)
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)
acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0, ACPI_MTX_DO_NOT_LOCK);
break;
}
}
/* Prepare to use new state. */
switch (new->type) {
case ACPI_STATE_C3:
/* Enable bus master reload */
if (old->type != ACPI_STATE_C3)
acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1, ACPI_MTX_DO_NOT_LOCK);
break;
}
pr->power.state = new;
return;
}
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;
pr = processors[raw_smp_processor_id()];
if (!pr)
return;
/*
* Interrupts must be disabled during bus mastering calculations and
* for C2/C3 transitions.
*/
local_irq_disable();
/*
* 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)
goto easy_out;
/*
* 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 > 32)
diff = 32;
while (diff) {
/* if we didn't get called, assume there was busmaster activity */
diff--;
if (diff)
pr->power.bm_activity |= 0x1;
pr->power.bm_activity <<= 1;
}
acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS,
&bm_status, ACPI_MTX_DO_NOT_LOCK);
if (bm_status) {
pr->power.bm_activity++;
acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS,
1, ACPI_MTX_DO_NOT_LOCK);
}
/*
* 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++;
}
pr->power.bm_check_timestamp = jiffies;
/*
* Apply bus mastering demotion policy. Automatically demote
* to avoid a faulty transition. Note that the processor
* won't enter a low-power state during this call (to this
* funciton) 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 & cx->demotion.threshold.bm) {
local_irq_enable();
next_state = cx->demotion.state;
goto end;
}
}
cx->usage++;
/*
* Sleep:
* ------
* Invoke the current Cx state to put the processor to sleep.
*/
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
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_fadt.xpm_tmr_blk.address);
/* Invoke C2 */
inb(cx->address);
/* Dummy op - must do something useless after P_LVL2 read */
t2 = inl(acpi_fadt.xpm_tmr_blk.address);
/* Get end time (ticks) */
t2 = inl(acpi_fadt.xpm_tmr_blk.address);
/* Re-enable interrupts */
local_irq_enable();
/* Compute time (ticks) that we were actually asleep */
sleep_ticks = ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
break;
case ACPI_STATE_C3:
/* Disable bus master arbitration */
acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1, ACPI_MTX_DO_NOT_LOCK);
/* Get start time (ticks) */
t1 = inl(acpi_fadt.xpm_tmr_blk.address);
/* Invoke C3 */
inb(cx->address);
/* Dummy op - must do something useless after P_LVL3 read */
t2 = inl(acpi_fadt.xpm_tmr_blk.address);
/* Get end time (ticks) */
t2 = inl(acpi_fadt.xpm_tmr_blk.address);
/* Enable bus master arbitration */
acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0, ACPI_MTX_DO_NOT_LOCK);
/* Re-enable interrupts */
local_irq_enable();
/* Compute time (ticks) that we were actually asleep */
sleep_ticks = ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;
break;
default:
local_irq_enable();
return;
}
next_state = pr->power.state;
/*
* 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.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
*/
if ((pr->power.state - pr->power.states) > max_cstate) {
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);
return;
easy_out:
/* do C1 instead of busy loop */
if (pm_idle_save)
pm_idle_save();
else
safe_halt();
return;
}
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;
ACPI_FUNCTION_TRACE("acpi_processor_set_power_policy");
if (!pr)
return_VALUE(-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_VALUE(-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_VALUE(0);
}
static int acpi_processor_get_power_info_fadt (struct acpi_processor *pr)
{
int i;
ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_fadt");
if (!pr)
return_VALUE(-EINVAL);
if (!pr->pblk)
return_VALUE(-ENODEV);
for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
memset(pr->power.states, 0, sizeof(struct acpi_processor_cx));
/* if info is obtained from pblk/fadt, type equals state */
pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
/* the C0 state only exists as a filler in our array,
* and all processors need to support C1 */
pr->power.states[ACPI_STATE_C0].valid = 1;
pr->power.states[ACPI_STATE_C1].valid = 1;
/* 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_fadt.plvl2_lat;
pr->power.states[ACPI_STATE_C3].latency = acpi_fadt.plvl3_lat;
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_VALUE(0);
}
static int acpi_processor_get_power_info_cst (struct acpi_processor *pr)
{
acpi_status status = 0;
acpi_integer count;
int i;
struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
union acpi_object *cst;
ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_cst");
if (errata.smp)
return_VALUE(-ENODEV);
if (nocst)
return_VALUE(-ENODEV);
pr->power.count = 0;
for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
memset(pr->power.states, 0, sizeof(struct acpi_processor_cx));
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_VALUE(-ENODEV);
}
cst = (union acpi_object *) buffer.pointer;
/* There must be at least 2 elements */
if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "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) {
ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "count given by _CST is not valid\n"));
status = -EFAULT;
goto end;
}
/* We support up to ACPI_PROCESSOR_MAX_POWER. */
if (count > ACPI_PROCESSOR_MAX_POWER) {
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");
count = ACPI_PROCESSOR_MAX_POWER;
}
/* 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 = (union acpi_object *) &(cst->package.elements[i]);
if (element->type != ACPI_TYPE_PACKAGE)
continue;
if (element->package.count != 4)
continue;
obj = (union acpi_object *) &(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;
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_C1) ||
(cx.type > ACPI_STATE_C3))
continue;
obj = (union acpi_object *) &(element->package.elements[2]);
if (obj->type != ACPI_TYPE_INTEGER)
continue;
cx.latency = obj->integer.value;
obj = (union acpi_object *) &(element->package.elements[3]);
if (obj->type != ACPI_TYPE_INTEGER)
continue;
cx.power = obj->integer.value;
(pr->power.count)++;
memcpy(&(pr->power.states[pr->power.count]), &cx, sizeof(cx));
}
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n", pr->power.count));
/* Validate number of power states discovered */
if (pr->power.count < 2)
status = -ENODEV;
end:
acpi_os_free(buffer.pointer);
return_VALUE(status);
}
static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
{
ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c2");
if (!cx->address)
return_VOID;
/*
* 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_VOID;
}
/* We're (currently) only supporting C2 on UP */
else if (errata.smp) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"C2 not supported in SMP mode\n"));
return_VOID;
}
/*
* 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_VOID;
}
static void acpi_processor_power_verify_c3(
struct acpi_processor *pr,
struct acpi_processor_cx *cx)
{
ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c3");
if (!cx->address)
return_VOID;
/*
* 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_VOID;
}
/* bus mastering control is necessary */
else if (!pr->flags.bm_control) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"C3 support requires bus mastering control\n"));
return_VOID;
}
/* We're (currently) only supporting C2 on UP */
else if (errata.smp) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"C3 not supported in SMP mode\n"));
return_VOID;
}
/*
* 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_VOID;
}
/*
* 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);
pr->flags.bm_check = 1;
return_VOID;
}
static int acpi_processor_power_verify(struct acpi_processor *pr)
{
unsigned int i;
unsigned int working = 0;
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);
break;
case ACPI_STATE_C3:
acpi_processor_power_verify_c3(pr, cx);
break;
}
if (cx->valid)
working++;
}
return (working);
}
static int acpi_processor_get_power_info (
struct acpi_processor *pr)
{
unsigned int i;
int result;
ACPI_FUNCTION_TRACE("acpi_processor_get_power_info");
/* NOTE: the idle thread may not be running while calling
* this function */
result = acpi_processor_get_power_info_cst(pr);
if ((result) || (acpi_processor_power_verify(pr) < 2)) {
result = acpi_processor_get_power_info_fadt(pr);
if (result)
return_VALUE(result);
if (acpi_processor_power_verify(pr) < 2)
return_VALUE(-ENODEV);
}
/*
* 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_VALUE(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].valid) &&
(pr->power.states[i].type >= ACPI_STATE_C2))
pr->flags.power = 1;
}
return_VALUE(0);
}
int acpi_processor_cst_has_changed (struct acpi_processor *pr)
{
int result = 0;
ACPI_FUNCTION_TRACE("acpi_processor_cst_has_changed");
if (!pr)
return_VALUE(-EINVAL);
if (errata.smp || nocst) {
return_VALUE(-ENODEV);
}
if (!pr->flags.power_setup_done)
return_VALUE(-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_VALUE(result);
}
/* proc interface */
static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
{
struct acpi_processor *pr = (struct acpi_processor *)seq->private;
unsigned int i;
ACPI_FUNCTION_TRACE("acpi_processor_power_seq_show");
if (!pr)
goto end;
seq_printf(seq, "active state: C%zd\n"
"max_cstate: C%d\n"
"bus master activity: %08x\n",
pr->power.state ? pr->power.state - pr->power.states : 0,
max_cstate,
(unsigned)pr->power.bm_activity);
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]\n",
pr->power.states[i].latency,
pr->power.states[i].usage);
}
end:
return_VALUE(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 struct file_operations acpi_processor_power_fops = {
.open = acpi_processor_power_open_fs,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
int acpi_processor_power_init(struct acpi_processor *pr, struct acpi_device *device)
{
acpi_status status = 0;
static int first_run = 0;
struct proc_dir_entry *entry = NULL;
unsigned int i;
ACPI_FUNCTION_TRACE("acpi_processor_power_init");
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++;
}
if (!errata.smp && (pr->id == 0) && acpi_fadt.cst_cnt && !nocst) {
status = acpi_os_write_port(acpi_fadt.smi_cmd, acpi_fadt.cst_cnt, 8);
if (ACPI_FAILURE(status)) {
ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
"Notifying BIOS of _CST ability failed\n"));
}
}
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)
ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
"Unable to create '%s' fs entry\n",
ACPI_PROCESSOR_FILE_POWER));
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_VALUE(0);
}
int acpi_processor_power_exit(struct acpi_processor *pr, struct acpi_device *device)
{
ACPI_FUNCTION_TRACE("acpi_processor_power_exit");
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();
}
return_VALUE(0);
}
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