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thermal/drivers/hisi: Remove costly sensor inspection
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The sensor is all setup, bind, resetted, acked, etc... every single second.

That was the way to workaround a problem with the interrupt bouncing again and
again.

With the following changes, we fix all in one:

 - Do the setup, one time, at probe time

 - Add the IRQF_ONESHOT, ack the interrupt in the threaded handler

 - Remove the interrupt handler

 - Set the correct value for the LAG register

 - Remove all the irq_enabled stuff in the code as the interruption
   handling is fixed

 - Remove the 3ms delay

 - Reorder the initialization routine to be in the right order

It ends up to a nicer code and more efficient, the 3-5ms delay is removed from
the get_temp() path.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Leo Yan <leo.yan@linaro.org>
Tested-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
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Daniel Lezcano authored and Eduardo Valentin committed Nov 1, 2017
1 parent b424315 commit 10d7e9a
Showing 1 changed file with 93 additions and 110 deletions.
203 changes: 93 additions & 110 deletions drivers/thermal/hisi_thermal.c
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Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,7 @@
#define HISI_TEMP_BASE (-60000)
#define HISI_TEMP_RESET (100000)
#define HISI_TEMP_STEP (784)
#define HISI_TEMP_LAG (3500)

#define HISI_MAX_SENSORS 4
#define HISI_DEFAULT_SENSOR 2
Expand All @@ -60,8 +61,6 @@ struct hisi_thermal_data {
struct clk *clk;
struct hisi_thermal_sensor sensors;
int irq;
bool irq_enabled;

void __iomem *regs;
};

Expand Down Expand Up @@ -99,9 +98,40 @@ static inline long hisi_thermal_round_temp(int temp)
hisi_thermal_temp_to_step(temp));
}

/*
* The lag register contains 5 bits encoding the temperature in steps.
*
* Each time the temperature crosses the threshold boundary, an
* interrupt is raised. It could be when the temperature is going
* above the threshold or below. However, if the temperature is
* fluctuating around this value due to the load, we can receive
* several interrupts which may not desired.
*
* We can setup a temperature representing the delta between the
* threshold and the current temperature when the temperature is
* decreasing.
*
* For instance: the lag register is 5°C, the threshold is 65°C, when
* the temperature reaches 65°C an interrupt is raised and when the
* temperature decrease to 65°C - 5°C another interrupt is raised.
*
* A very short lag can lead to an interrupt storm, a long lag
* increase the latency to react to the temperature changes. In our
* case, that is not really a problem as we are polling the
* temperature.
*
* [0:4] : lag register
*
* The temperature is coded in steps, cf. HISI_TEMP_STEP.
*
* Min : 0x00 : 0.0 °C
* Max : 0x1F : 24.3 °C
*
* The 'value' parameter is in milliCelsius.
*/
static inline void hisi_thermal_set_lag(void __iomem *addr, int value)
{
writel(value, addr + TEMP0_LAG);
writel((value / HISI_TEMP_STEP) & 0x1F, addr + TEMP0_LAG);
}

static inline void hisi_thermal_alarm_clear(void __iomem *addr, int value)
Expand Down Expand Up @@ -171,71 +201,6 @@ static inline void hisi_thermal_hdak_set(void __iomem *addr, int value)
(value << 4), addr + TEMP0_CFG);
}

static long hisi_thermal_get_sensor_temp(struct hisi_thermal_data *data,
struct hisi_thermal_sensor *sensor)
{
long val;

mutex_lock(&data->thermal_lock);

/* disable interrupt */
hisi_thermal_alarm_enable(data->regs, 0);
hisi_thermal_alarm_clear(data->regs, 1);

/* disable module firstly */
hisi_thermal_enable(data->regs, 0);

/* select sensor id */
hisi_thermal_sensor_select(data->regs, sensor->id);

/* enable module */
hisi_thermal_enable(data->regs, 1);

usleep_range(3000, 5000);

val = hisi_thermal_get_temperature(data->regs);

mutex_unlock(&data->thermal_lock);

return val;
}

static void hisi_thermal_enable_bind_irq_sensor
(struct hisi_thermal_data *data)
{
struct hisi_thermal_sensor *sensor;

mutex_lock(&data->thermal_lock);

sensor = &data->sensors;

/* setting the hdak time */
hisi_thermal_hdak_set(data->regs, 0);

/* disable module firstly */
hisi_thermal_reset_enable(data->regs, 0);
hisi_thermal_enable(data->regs, 0);

/* select sensor id */
hisi_thermal_sensor_select(data->regs, sensor->id);

/* enable for interrupt */
hisi_thermal_alarm_set(data->regs, sensor->thres_temp);

hisi_thermal_reset_set(data->regs, HISI_TEMP_RESET);

/* enable module */
hisi_thermal_reset_enable(data->regs, 1);
hisi_thermal_enable(data->regs, 1);

hisi_thermal_alarm_clear(data->regs, 0);
hisi_thermal_alarm_enable(data->regs, 1);

usleep_range(3000, 5000);

mutex_unlock(&data->thermal_lock);
}

static void hisi_thermal_disable_sensor(struct hisi_thermal_data *data)
{
mutex_lock(&data->thermal_lock);
Expand All @@ -253,25 +218,10 @@ static int hisi_thermal_get_temp(void *_sensor, int *temp)
struct hisi_thermal_sensor *sensor = _sensor;
struct hisi_thermal_data *data = sensor->thermal;

*temp = hisi_thermal_get_sensor_temp(data, sensor);

dev_dbg(&data->pdev->dev, "id=%d, irq=%d, temp=%d, thres=%d\n",
sensor->id, data->irq_enabled, *temp, sensor->thres_temp);
/*
* Bind irq to sensor for two cases:
* Reenable alarm IRQ if temperature below threshold;
* if irq has been enabled, always set it;
*/
if (data->irq_enabled) {
hisi_thermal_enable_bind_irq_sensor(data);
return 0;
}
*temp = hisi_thermal_get_temperature(data->regs);

if (*temp < sensor->thres_temp) {
data->irq_enabled = true;
hisi_thermal_enable_bind_irq_sensor(data);
enable_irq(data->irq);
}
dev_dbg(&data->pdev->dev, "id=%d, temp=%d, thres=%d\n",
sensor->id, *temp, sensor->thres_temp);

return 0;
}
Expand All @@ -280,26 +230,27 @@ static const struct thermal_zone_of_device_ops hisi_of_thermal_ops = {
.get_temp = hisi_thermal_get_temp,
};

static irqreturn_t hisi_thermal_alarm_irq(int irq, void *dev)
static irqreturn_t hisi_thermal_alarm_irq_thread(int irq, void *dev)
{
struct hisi_thermal_data *data = dev;
struct hisi_thermal_sensor *sensor = &data->sensors;
int temp;

disable_irq_nosync(irq);
data->irq_enabled = false;
hisi_thermal_alarm_clear(data->regs, 1);

return IRQ_WAKE_THREAD;
}
temp = hisi_thermal_get_temperature(data->regs);

static irqreturn_t hisi_thermal_alarm_irq_thread(int irq, void *dev)
{
struct hisi_thermal_data *data = dev;
struct hisi_thermal_sensor *sensor = &data->sensors;
if (temp >= sensor->thres_temp) {
dev_crit(&data->pdev->dev, "THERMAL ALARM: %d > %d\n",
temp, sensor->thres_temp);

dev_crit(&data->pdev->dev, "THERMAL ALARM: T > %d\n",
sensor->thres_temp);
thermal_zone_device_update(data->sensors.tzd,
THERMAL_EVENT_UNSPECIFIED);

thermal_zone_device_update(data->sensors.tzd,
THERMAL_EVENT_UNSPECIFIED);
} else if (temp < sensor->thres_temp) {
dev_crit(&data->pdev->dev, "THERMAL ALARM stopped: %d < %d\n",
temp, sensor->thres_temp);
}

return IRQ_HANDLED;
}
Expand Down Expand Up @@ -352,6 +303,40 @@ static void hisi_thermal_toggle_sensor(struct hisi_thermal_sensor *sensor,
on ? THERMAL_DEVICE_ENABLED : THERMAL_DEVICE_DISABLED);
}

static int hisi_thermal_setup(struct hisi_thermal_data *data)
{
struct hisi_thermal_sensor *sensor;

sensor = &data->sensors;

/* disable module firstly */
hisi_thermal_reset_enable(data->regs, 0);
hisi_thermal_enable(data->regs, 0);

/* select sensor id */
hisi_thermal_sensor_select(data->regs, sensor->id);

/* setting the hdak time */
hisi_thermal_hdak_set(data->regs, 0);

/* setting lag value between current temp and the threshold */
hisi_thermal_set_lag(data->regs, HISI_TEMP_LAG);

/* enable for interrupt */
hisi_thermal_alarm_set(data->regs, sensor->thres_temp);

hisi_thermal_reset_set(data->regs, HISI_TEMP_RESET);

/* enable module */
hisi_thermal_reset_enable(data->regs, 1);
hisi_thermal_enable(data->regs, 1);

hisi_thermal_alarm_clear(data->regs, 0);
hisi_thermal_alarm_enable(data->regs, 1);

return 0;
}

static int hisi_thermal_probe(struct platform_device *pdev)
{
struct hisi_thermal_data *data;
Expand Down Expand Up @@ -394,9 +379,6 @@ static int hisi_thermal_probe(struct platform_device *pdev)
return ret;
}

hisi_thermal_enable_bind_irq_sensor(data);
data->irq_enabled = true;

ret = hisi_thermal_register_sensor(pdev, data,
&data->sensors,
HISI_DEFAULT_SENSOR);
Expand All @@ -406,18 +388,21 @@ static int hisi_thermal_probe(struct platform_device *pdev)
return ret;
}

hisi_thermal_toggle_sensor(&data->sensors, true);
ret = hisi_thermal_setup(data);
if (ret) {
dev_err(&pdev->dev, "Failed to setup the sensor: %d\n", ret);
return ret;
}

ret = devm_request_threaded_irq(&pdev->dev, data->irq,
hisi_thermal_alarm_irq,
ret = devm_request_threaded_irq(&pdev->dev, data->irq, NULL,
hisi_thermal_alarm_irq_thread,
0, "hisi_thermal", data);
IRQF_ONESHOT, "hisi_thermal", data);
if (ret < 0) {
dev_err(&pdev->dev, "failed to request alarm irq: %d\n", ret);
return ret;
}

enable_irq(data->irq);
hisi_thermal_toggle_sensor(&data->sensors, true);

return 0;
}
Expand All @@ -440,7 +425,6 @@ static int hisi_thermal_suspend(struct device *dev)
struct hisi_thermal_data *data = dev_get_drvdata(dev);

hisi_thermal_disable_sensor(data);
data->irq_enabled = false;

clk_disable_unprepare(data->clk);

Expand All @@ -456,8 +440,7 @@ static int hisi_thermal_resume(struct device *dev)
if (ret)
return ret;

data->irq_enabled = true;
hisi_thermal_enable_bind_irq_sensor(data);
hisi_thermal_setup(data);

return 0;
}
Expand Down

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