Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity
kernel-fxtec-pro1x/drivers/acpi/processor_idle.c
Arjan van de Ven 5c87579e65 [PATCH] maximum latency tracking infrastructure 
Add infrastructure to track "maximum allowable latency" for power saving
policies.

The reason for adding this infrastructure is that power management in the
idle loop needs to make a tradeoff between latency and power savings
(deeper power save modes have a longer latency to running code again).  The
code that today makes this tradeoff just does a rather simple algorithm;
however this is not good enough: There are devices and use cases where a
lower latency is required than that the higher power saving states provide.
 An example would be audio playback, but another example is the ipw2100
wireless driver that right now has a very direct and ugly acpi hook to
disable some higher power states randomly when it gets certain types of
error.

The proposed solution is to have an interface where drivers can

* announce the maximum latency (in microseconds) that they can deal with
* modify this latency
* give up their constraint

and a function where the code that decides on power saving strategy can
query the current global desired maximum.

This patch has a user of each side: on the consumer side, ACPI is patched
to use this, on the producer side the ipw2100 driver is patched.

A generic maximum latency is also registered of 2 timer ticks (more and you
lose accurate time tracking after all).

While the existing users of the patch are x86 specific, the infrastructure
is not.  I'd like to ask the arch maintainers of other architectures if the
infrastructure is generic enough for their use (assuming the architecture
has such a tradeoff as concept at all), and the sound/multimedia driver
owners to look at the driver facing API to see if this is something they
can use.

[akpm@osdl.org: cleanups]
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Jesse Barnes <jesse.barnes@intel.com>
Cc: "Brown, Len" <len.brown@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-01 00:39:19 -07:00

1200 lines
31 KiB
C
Raw Blame History

/*
* 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 <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) __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_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)
{
current_thread_info()->status &= ~TS_POLLING;
smp_mb__after_clear_bit();
if (!need_resched())
safe_halt();
current_thread_info()->status |= TS_POLLING;
}
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 > 31)
diff = 31;
pr->power.bm_activity <<= diff;
acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS,
&bm_status, ACPI_MTX_DO_NOT_LOCK);
if (bm_status) {
pr->power.bm_activity |= 0x1;
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 |= 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_fadt.plvl2_up)
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;
smp_mb__after_clear_bit();
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_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);
/* Get end time (ticks) */
t2 = inl(acpi_fadt.xpm_tmr_blk.address);
#ifdef CONFIG_GENERIC_TIME
/* TSC halts in C2, so notify users */
mark_tsc_unstable();
#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;
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 wait op (see above) */
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);
}
#ifdef CONFIG_GENERIC_TIME
/* TSC halts in C3, so notify users */
mark_tsc_unstable();
#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;
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_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.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_fadt.plvl2_up)
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_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 0;
}
static int acpi_processor_get_power_info_default_c1(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 */
pr->power.states[ACPI_STATE_C0].valid = 1;
pr->power.states[ACPI_STATE_C1].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 = 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));
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 = (union acpi_object *)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 = (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_C2) || (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;
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_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;
}
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;
}
static int acpi_processor_power_verify(struct acpi_processor *pr)
{
unsigned int i;
unsigned int working = 0;
#ifdef ARCH_APICTIMER_STOPS_ON_C3
int timer_broadcast = 0;
cpumask_t mask = cpumask_of_cpu(pr->id);
on_each_cpu(switch_ipi_to_APIC_timer, &mask, 1, 1);
#endif
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);
#ifdef ARCH_APICTIMER_STOPS_ON_C3
/* Some AMD systems fake C3 as C2, but still
have timer troubles */
if (cx->valid &&
boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
timer_broadcast++;
#endif
break;
case ACPI_STATE_C3:
acpi_processor_power_verify_c3(pr, cx);
#ifdef ARCH_APICTIMER_STOPS_ON_C3
if (cx->valid)
timer_broadcast++;
#endif
break;
}
if (cx->valid)
working++;
}
#ifdef ARCH_APICTIMER_STOPS_ON_C3
if (timer_broadcast)
on_each_cpu(switch_APIC_timer_to_ipi, &mask, 1, 1);
#endif
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 */
/* Adding C1 state */
acpi_processor_get_power_info_default_c1(pr);
result = acpi_processor_get_power_info_cst(pr);
if (result == -ENODEV)
acpi_processor_get_power_info_fadt(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 = (struct acpi_processor *)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,
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,
};
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,
};
int 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++;
register_latency_notifier(&acpi_processor_latency_notifier);
}
if (!pr)
return -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_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();
unregister_latency_notifier(&acpi_processor_latency_notifier);
}
return 0;
}
Reference in a new issue View git blame Copy permalink