[PATCH 1/2] thermal: devfreq_cooling: Use PM QoS to set frequency limits

From: Matthias Kaehlcke
Date: Fri Jan 10 2020 - 12:49:27 EST


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.

Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
---

drivers/thermal/devfreq_cooling.c | 66 ++++++++++---------------------
1 file changed, 20 insertions(+), 46 deletions(-)

diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c
index ef59256887ff..3a63603afcf2 100644
--- a/drivers/thermal/devfreq_cooling.c
+++ b/drivers/thermal/devfreq_cooling.c
@@ -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);

@@ -65,49 +67,9 @@ 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)
{
@@ -134,7 +96,7 @@ 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;
@@ -144,9 +106,10 @@ 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;

@@ -529,6 +492,12 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
if (err)
goto free_dfc;

+ 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 remove_qos_req;
+
err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL);
if (err < 0)
goto free_tables;
@@ -552,6 +521,10 @@ 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);
@@ -600,6 +573,7 @@ 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);

--
2.25.0.rc1.283.g88dfdc4193-goog