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thermal: devfreq_cooling: Use PM QoS to set frequency limits

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Now that devfreq supports limiting the frequency range of a device
through PM QoS make use of it instead of disabling OPPs that should
not be used.

The switch from disabling OPPs to PM QoS introduces a subtle behavioral
change in case of conflicting requests (min > max): PM QoS gives
precedence to the MIN_FREQUENCY request, while higher OPPs disabled
with dev_pm_opp_disable() would override MIN_FREQUENCY.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200318114548.19916-4-lukasz.luba@arm.com
This commit is contained in:
Matthias Kaehlcke 2020-03-18 11:45:46 +00:00 committed by Daniel Lezcano
parent 44fc73223e
commit 04fa9c804b
1 changed files with 23 additions and 47 deletions
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70
drivers/thermal/devfreq_cooling.c
View File

@ -24,11 +24,13 @@
#include <linux/idr.h>
#include <linux/slab.h>
#include <linux/pm_opp.h>
#include <linux/pm_qos.h>
#include <linux/thermal.h>
#include <trace/events/thermal.h>
#define SCALE_ERROR_MITIGATION 100
#define HZ_PER_KHZ 1000
#define SCALE_ERROR_MITIGATION 100
static DEFINE_IDA(devfreq_ida);
@ -54,6 +56,8 @@ static DEFINE_IDA(devfreq_ida);
* The 'res_util' range is from 100 to (power_table[state] * 100)
* for the corresponding 'state'.
* @capped_state: index to cooling state with in dynamic power budget
* @req_max_freq: PM QoS request for limiting the maximum frequency
* of the devfreq device.
*/
struct devfreq_cooling_device {
int id;
@ -66,49 +70,9 @@ struct devfreq_cooling_device {
struct devfreq_cooling_power *power_ops;
u32 res_util;
int capped_state;
struct dev_pm_qos_request req_max_freq;
};
/**
* partition_enable_opps() - disable all opps above a given state
* @dfc: Pointer to devfreq we are operating on
* @cdev_state: cooling device state we're setting
*
* Go through the OPPs of the device, enabling all OPPs until
* @cdev_state and disabling those frequencies above it.
*/
static int partition_enable_opps(struct devfreq_cooling_device *dfc,
unsigned long cdev_state)
{
int i;
struct device *dev = dfc->devfreq->dev.parent;
for (i = 0; i < dfc->freq_table_size; i++) {
struct dev_pm_opp *opp;
int ret = 0;
unsigned int freq = dfc->freq_table[i];
bool want_enable = i >= cdev_state ? true : false;
opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable);
if (PTR_ERR(opp) == -ERANGE)
continue;
else if (IS_ERR(opp))
return PTR_ERR(opp);
dev_pm_opp_put(opp);
if (want_enable)
ret = dev_pm_opp_enable(dev, freq);
else
ret = dev_pm_opp_disable(dev, freq);
if (ret)
return ret;
}
return 0;
}
static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
@ -135,7 +99,7 @@ static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
struct devfreq_cooling_device *dfc = cdev->devdata;
struct devfreq *df = dfc->devfreq;
struct device *dev = df->dev.parent;
int ret;
unsigned long freq;
if (state == dfc->cooling_state)
return 0;
@ -145,9 +109,10 @@ static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
if (state >= dfc->freq_table_size)
return -EINVAL;
ret = partition_enable_opps(dfc, state);
if (ret)
return ret;
freq = dfc->freq_table[state];
dev_pm_qos_update_request(&dfc->req_max_freq,
DIV_ROUND_UP(freq, HZ_PER_KHZ));
dfc->cooling_state = state;
@ -530,9 +495,15 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
if (err)
goto free_dfc;
err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL);
err = dev_pm_qos_add_request(df->dev.parent, &dfc->req_max_freq,
DEV_PM_QOS_MAX_FREQUENCY,
PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
if (err < 0)
goto free_tables;
err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL);
if (err < 0)
goto remove_qos_req;
dfc->id = err;
snprintf(dev_name, sizeof(dev_name), "thermal-devfreq-%d", dfc->id);
@ -553,6 +524,10 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
release_ida:
ida_simple_remove(&devfreq_ida, dfc->id);
remove_qos_req:
dev_pm_qos_remove_request(&dfc->req_max_freq);
free_tables:
kfree(dfc->power_table);
kfree(dfc->freq_table);
@ -601,6 +576,7 @@ void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
thermal_cooling_device_unregister(dfc->cdev);
ida_simple_remove(&devfreq_ida, dfc->id);
dev_pm_qos_remove_request(&dfc->req_max_freq);
kfree(dfc->power_table);
kfree(dfc->freq_table);