/*
* processor_thermal.c - Passive cooling submodule of 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/sysdev.h>
#include <asm/uaccess.h>
#include <acpi/acpi_bus.h>
#include <acpi/processor.h>
#include <acpi/acpi_drivers.h>
#define PREFIX "ACPI: "
#define ACPI_PROCESSOR_CLASS "processor"
#define _COMPONENT ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME("processor_thermal");
/* --------------------------------------------------------------------------
Limit Interface
-------------------------------------------------------------------------- */
static int acpi_processor_apply_limit(struct acpi_processor *pr)
{
int result = 0;
u16 px = 0;
u16 tx = 0;
if (!pr)
return -EINVAL;
if (!pr->flags.limit)
return -ENODEV;
if (pr->flags.throttling) {
if (pr->limit.user.tx > tx)
tx = pr->limit.user.tx;
if (pr->limit.thermal.tx > tx)
tx = pr->limit.thermal.tx;
result = acpi_processor_set_throttling(pr, tx, false);
if (result)
goto end;
}
pr->limit.state.px = px;
pr->limit.state.tx = tx;
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Processor [%d] limit set to (P%d:T%d)\n", pr->id,
pr->limit.state.px, pr->limit.state.tx));
end:
if (result)
printk(KERN_ERR PREFIX "Unable to set limit\n");
return result;
}
#ifdef CONFIG_CPU_FREQ
/* If a passive cooling situation is detected, primarily CPUfreq is used, as it
* offers (in most cases) voltage scaling in addition to frequency scaling, and
* thus a cubic (instead of linear) reduction of energy. Also, we allow for
* _any_ cpufreq driver and not only the acpi-cpufreq driver.
*/
#define CPUFREQ_THERMAL_MIN_STEP 0
#define CPUFREQ_THERMAL_MAX_STEP 3
static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
static unsigned int acpi_thermal_cpufreq_is_init = 0;
static int cpu_has_cpufreq(unsigned int cpu)
{
struct cpufreq_policy policy;
if (!acpi_thermal_cpufreq_is_init || cpufreq_get_policy(&policy, cpu))
return 0;
return 1;
}
static int acpi_thermal_cpufreq_increase(unsigned int cpu)
{
if (!cpu_has_cpufreq(cpu))
return -ENODEV;
if (per_cpu(cpufreq_thermal_reduction_pctg, cpu) <
CPUFREQ_THERMAL_MAX_STEP) {
per_cpu(cpufreq_thermal_reduction_pctg, cpu)++;
cpufreq_update_policy(cpu);
return 0;
}
return -ERANGE;
}
static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
{
if (!cpu_has_cpufreq(cpu))
return -ENODEV;
if (per_cpu(cpufreq_thermal_reduction_pctg, cpu) >
(CPUFREQ_THERMAL_MIN_STEP + 1))
per_cpu(cpufreq_thermal_reduction_pctg, cpu)--;
else
per_cpu(cpufreq_thermal_reduction_pctg, cpu) = 0;
cpufreq_update_policy(cpu);
/* We reached max freq again and can leave passive mode */
return !per_cpu(cpufreq_thermal_reduction_pctg, cpu);
}
static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
unsigned long event, void *data)
{
struct cpufreq_policy *policy = data;
unsigned long max_freq = 0;
if (event != CPUFREQ_ADJUST)
goto out;
max_freq = (
policy->cpuinfo.max_freq *
(100 - per_cpu(cpufreq_thermal_reduction_pctg, policy->cpu) * 20)
) / 100;
cpufreq_verify_within_limits(policy, 0, max_freq);
out:
return 0;
}
static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
.notifier_call = acpi_thermal_cpufreq_notifier,
};
static int cpufreq_get_max_state(unsigned int cpu)
{
if (!cpu_has_cpufreq(cpu))
return 0;
return CPUFREQ_THERMAL_MAX_STEP;
}
static int cpufreq_get_cur_state(unsigned int cpu)
{
if (!cpu_has_cpufreq(cpu))
return 0;
return per_cpu(cpufreq_thermal_reduction_pctg, cpu);
}
static int cpufreq_set_cur_state(unsigned int cpu, int state)
{
if (!cpu_has_cpufreq(cpu))
return 0;
per_cpu(cpufreq_thermal_reduction_pctg, cpu) = state;
cpufreq_update_policy(cpu);
return 0;
}
void acpi_thermal_cpufreq_init(void)
{
int i;
for (i = 0; i < nr_cpu_ids; i++)
if (cpu_present(i))
per_cpu(cpufreq_thermal_reduction_pctg, i) = 0;
i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
CPUFREQ_POLICY_NOTIFIER);
if (!i)
acpi_thermal_cpufreq_is_init = 1;
}
void acpi_thermal_cpufreq_exit(void)
{
if (acpi_thermal_cpufreq_is_init)
cpufreq_unregister_notifier
(&acpi_thermal_cpufreq_notifier_block,
CPUFREQ_POLICY_NOTIFIER);
acpi_thermal_cpufreq_is_init = 0;
}
#else /* ! CONFIG_CPU_FREQ */
static int cpufreq_get_max_state(unsigned int cpu)
{
return 0;
}
static int cpufreq_get_cur_state(unsigned int cpu)
{
return 0;
}
static int cpufreq_set_cur_state(unsigned int cpu, int state)
{
return 0;
}
static int acpi_thermal_cpufreq_increase(unsigned int cpu)
{
return -ENODEV;
}
static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
{
return -ENODEV;
}
#endif
int acpi_processor_set_thermal_limit(acpi_handle handle, int type)
{
int result = 0;
struct acpi_processor *pr = NULL;
struct acpi_device *device = NULL;
int tx = 0, max_tx_px = 0;
if ((type < ACPI_PROCESSOR_LIMIT_NONE)
|| (type > ACPI_PROCESSOR_LIMIT_DECREMENT))
return -EINVAL;
result = acpi_bus_get_device(handle, &device);
if (result)
return result;
pr = acpi_driver_data(device);
if (!pr)
return -ENODEV;
/* Thermal limits are always relative to the current Px/Tx state. */
if (pr->flags.throttling)
pr->limit.thermal.tx = pr->throttling.state;
/*
* Our default policy is to only use throttling at the lowest
* performance state.
*/
tx = pr->limit.thermal.tx;
switch (type) {
case ACPI_PROCESSOR_LIMIT_NONE:
do {
result = acpi_thermal_cpufreq_decrease(pr->id);
} while (!result);
tx = 0;
break;
case ACPI_PROCESSOR_LIMIT_INCREMENT:
/* if going up: P-states first, T-states later */
result = acpi_thermal_cpufreq_increase(pr->id);
if (!result)
goto end;
else if (result == -ERANGE)
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"At maximum performance state\n"));
if (pr->flags.throttling) {
if (tx == (pr->throttling.state_count - 1))
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"At maximum throttling state\n"));
else
tx++;
}
break;
case ACPI_PROCESSOR_LIMIT_DECREMENT:
/* if going down: T-states first, P-states later */
if (pr->flags.throttling) {
if (tx == 0) {
max_tx_px = 1;
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"At minimum throttling state\n"));
} else {
tx--;
goto end;
}
}
result = acpi_thermal_cpufreq_decrease(pr->id);
if (result) {
/*
* We only could get -ERANGE, 1 or 0.
* In the first two cases we reached max freq again.
*/
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"At minimum performance state\n"));
max_tx_px = 1;
} else
max_tx_px = 0;
break;
}
end:
if (pr->flags.throttling) {
pr->limit.thermal.px = 0;
pr->limit.thermal.tx = tx;
result = acpi_processor_apply_limit(pr);
if (result)
printk(KERN_ERR PREFIX "Unable to set thermal limit\n");
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Thermal limit now (P%d:T%d)\n",
pr->limit.thermal.px, pr->limit.thermal.tx));
} else
result = 0;
if (max_tx_px)
return 1;
else
return result;
}
int acpi_processor_get_limit_info(struct acpi_processor *pr)
{
if (!pr)
return -EINVAL;
if (pr->flags.throttling)
pr->flags.limit = 1;
return 0;
}
/* thermal coolign device callbacks */
static int acpi_processor_max_state(struct acpi_processor *pr)
{
int max_state = 0;
/*
* There exists four states according to
* cpufreq_thermal_reduction_ptg. 0, 1, 2, 3
*/
max_state += cpufreq_get_max_state(pr->id);
if (pr->flags.throttling)
max_state += (pr->throttling.state_count -1);
return max_state;
}
static int
processor_get_max_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
struct acpi_device *device = cdev->devdata;
struct acpi_processor *pr = acpi_driver_data(device);
if (!device || !pr)
return -EINVAL;
*state = acpi_processor_max_state(pr);
return 0;
}
static int
processor_get_cur_state(struct thermal_cooling_device *cdev,
unsigned long *cur_state)
{
struct acpi_device *device = cdev->devdata;
struct acpi_processor *pr = acpi_driver_data(device);
if (!device || !pr)
return -EINVAL;
*cur_state = cpufreq_get_cur_state(pr->id);
if (pr->flags.throttling)
*cur_state += pr->throttling.state;
return 0;
}
static int
processor_set_cur_state(struct thermal_cooling_device *cdev,
unsigned long state)
{
struct acpi_device *device = cdev->devdata;
struct acpi_processor *pr = acpi_driver_data(device);
int result = 0;
int max_pstate;
if (!device || !pr)
return -EINVAL;
max_pstate = cpufreq_get_max_state(pr->id);
if (state > acpi_processor_max_state(pr))
return -EINVAL;
if (state <= max_pstate) {
if (pr->flags.throttling && pr->throttling.state)
result = acpi_processor_set_throttling(pr, 0, false);
cpufreq_set_cur_state(pr->id, state);
} else {
cpufreq_set_cur_state(pr->id, max_pstate);
result = acpi_processor_set_throttling(pr,
state - max_pstate, false);
}
return result;
}
struct thermal_cooling_device_ops processor_cooling_ops = {
.get_max_state = processor_get_max_state,
.get_cur_state = processor_get_cur_state,
.set_cur_state = processor_set_cur_state,
};
