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linux-stable/drivers/acpi/processor_idle.c
Len Brown 927fe18397 Pull 5165 into release branch
2005-12-05 17:08:40 -05:00

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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
* 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 <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 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;
}
static struct dmi_system_id __initdata processor_power_dmi_table[] = {
{set_max_cstate, "IBM ThinkPad R40e", {
DMI_MATCH(DMI_BIOS_VENDOR,
"IBM"),
DMI_MATCH(DMI_BIOS_VERSION,
"1SET60WW")},
(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_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 && pr->flags.bm_check)
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 && pr->flags.bm_check)
acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1,
ACPI_MTX_DO_NOT_LOCK);
break;
}
pr->power.state = new;
return;
}
static void acpi_safe_halt(void)
{
clear_thread_flag(TIF_POLLING_NRFLAG);
smp_mb__after_clear_bit();
if (!need_resched())
safe_halt();
set_thread_flag(TIF_POLLING_NRFLAG);
}
static atomic_t c3_cpu_count;
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[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) {
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 > 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;
}
}
#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_fadt.plvl2_up)
cx = &pr->power.states[ACPI_STATE_C1];
#endif
cx->usage++;
/*
* Sleep:
* ------
* Invoke the current Cx state to put the processor to sleep.
*/
if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
clear_thread_flag(TIF_POLLING_NRFLAG);
smp_mb__after_clear_bit();
if (need_resched()) {
set_thread_flag(TIF_POLLING_NRFLAG);
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_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();
set_thread_flag(TIF_POLLING_NRFLAG);
/* Compute time (ticks) that we were actually asleep */
sleep_ticks =
ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
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,
ACPI_MTX_DO_NOT_LOCK);
}
} else {
/* SMP with no shared cache... Invalidate cache */
ACPI_FLUSH_CPU_CACHE();
}
/* 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);
if (pr->flags.bm_check) {
/* Enable bus master arbitration */
atomic_dec(&c3_cpu_count);
acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0,
ACPI_MTX_DO_NOT_LOCK);
}
/* Re-enable interrupts */
local_irq_enable();
set_thread_flag(TIF_POLLING_NRFLAG);
/* 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;
#ifdef CONFIG_HOTPLUG_CPU
/* Don't do promotion/demotion */
if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) &&
!pr->flags.has_cst && !acpi_fadt.plvl2_up) {
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.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);
}
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)
{
ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_fadt");
if (!pr)
return_VALUE(-EINVAL);
if (!pr->pblk)
return_VALUE(-ENODEV);
memset(pr->power.states, 0, sizeof(pr->power.states));
/* 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;
#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_fadt.plvl2_up)
return_VALUE(-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_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_default_c1(struct acpi_processor *pr)
{
ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_default_c1");
memset(pr->power.states, 0, sizeof(pr->power.states));
/* 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;
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 (nocst)
return_VALUE(-ENODEV);
pr->power.count = 0;
for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
memset(&(pr->power.states[i]), 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 = -EFAULT;
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;
}
/*
* 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)
{
static int bm_check_flag;
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;
}
/*
* 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;
}
/* 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_VOID;
}
} else {
/*
* WBINVD should be set in fadt, for C3 state to be
* supported on when bm_check is not required.
*/
if (acpi_fadt.wb_invd != 1) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Cache invalidation should work properly"
" for C3 to be enabled on SMP systems\n"));
return_VOID;
}
acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD,
0, ACPI_MTX_DO_NOT_LOCK);
}
/*
* 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_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 == -ENODEV)
result = acpi_processor_get_power_info_fadt(pr);
if ((result) || (acpi_processor_power_verify(pr) < 2))
result = acpi_processor_get_power_info_default_c1(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_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].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 (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 (!pr)
return_VALUE(-EINVAL);
if (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_power_init_pdc(&(pr->power), pr->id);
acpi_processor_set_pdc(pr, pr->power.pdc);
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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