[PATCH 4/6] hwmon: amd_energy: let user enable/disable the sw accumulation

Naveen Krishna Chatradhi
2020-09-05T14:33:04Z

Provide an option "accumulator_status" via sysfs to enable/disable
the software accumulation of energy counters.

Signed-off-by: Naveen Krishna Chatradhi <nchatrad@amd.com>
---
drivers/hwmon/amd_energy.c | 104 ++++++++++++++++++++++++++++++-------
1 file changed, 86 insertions(+), 18 deletions(-)

diff --git a/drivers/hwmon/amd_energy.c b/drivers/hwmon/amd_energy.c
index 96c61784d05c..c294bea56c02 100644
--- a/drivers/hwmon/amd_energy.c
+++ b/drivers/hwmon/amd_energy.c
@@ -32,6 +32,8 @@
#define AMD_ENERGY_UNIT_MASK 0x01F00
#define AMD_ENERGY_MASK 0xFFFFFFFF

+static struct device_attribute accumulate_attr;
+
struct sensor_accumulator {
u64 energy_ctr;
u64 prev_value;
@@ -42,10 +44,12 @@ struct amd_energy_data {
const struct hwmon_channel_info *info[2];
struct hwmon_chip_info chip;
struct task_struct *wrap_accumulate;
+ struct device *hwmon_dev;
/* Lock around the accumulator */
struct mutex lock;
/* An accumulator for each core and socket */
struct sensor_accumulator *accums;
+ bool accumulator_status;
/* Energy Status Units */
u64 energy_units;
unsigned int timeout;
@@ -128,13 +132,15 @@ static void amd_add_delta(struct amd_energy_data *data, int ch,
rdmsrl_safe_on_cpu(cpu, reg, &input);
input &= AMD_ENERGY_MASK;

- accum = &data->accums[ch];
- if (input >= accum->prev_value)
- input += accum->energy_ctr -
- accum->prev_value;
- else
- input += UINT_MAX - accum->prev_value +
- accum->energy_ctr;
+ if (data->accumulator_status) {
+ accum = &data->accums[ch];
+ if (input >= accum->prev_value)
+ input += accum->energy_ctr -
+ accum->prev_value;
+ else
+ input += UINT_MAX - accum->prev_value +
+ accum->energy_ctr;
+ }

/* Energy consumed = (1/(2^ESU) * RAW * 1000000UL) μJoules */
*val = div64_ul(input * 1000000UL, BIT(data->energy_units));
@@ -264,9 +270,67 @@ static int amd_create_sensor(struct device *dev,
return 0;
}

+static ssize_t amd_energy_accumulate_show(struct device *dev,
+ struct device_attribute *dev_attr,
+ char *buf)
+{
+ struct amd_energy_data *data = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n", data->accumulator_status);
+}
+
+static ssize_t amd_energy_accumulate_store(struct device *dev,
+ struct device_attribute *dev_attr,
+ const char *buf, size_t count)
+{
+ struct amd_energy_data *data = dev_get_drvdata(dev);
+ bool input;
+ int ret;
+
+ ret = kstrtobool(buf, &input);
+ if (ret)
+ return ret;
+
+ if (data->accumulator_status == input)
+ return count;
+
+ if (input) {
+ memset(data->accums, 0, (data->nr_cpus + data->nr_socks) *
+ sizeof(struct sensor_accumulator));
+
+ if (!data->wrap_accumulate) {
+ data->wrap_accumulate =
+ kthread_run(energy_accumulator,
+ data, "%s", dev_name(dev));
+ if (IS_ERR(data->wrap_accumulate))
+ return PTR_ERR(data->wrap_accumulate);
+ }
+ } else {
+ if (data && data->wrap_accumulate) {
+ ret = kthread_stop(data->wrap_accumulate);
+ if (ret)
+ return ret;
+ data->wrap_accumulate = NULL;
+ }
+ }
+ data->accumulator_status = input;
+
+ return count;
+}
+
+static int create_accumulate_status_file(struct amd_energy_data *data)
+{
+ accumulate_attr.attr.name = "accumulator_status";
+ accumulate_attr.attr.mode = 0664;
+ accumulate_attr.show = amd_energy_accumulate_show;
+ accumulate_attr.store = amd_energy_accumulate_store;
+
+ return sysfs_create_file(&data->hwmon_dev->kobj,
+ &accumulate_attr.attr);
+}
+
static int amd_energy_probe(struct platform_device *pdev)
{
- struct device *hwmon_dev;
struct amd_energy_data *data;
struct device *dev = &pdev->dev;
int ret;
@@ -290,12 +354,12 @@ static int amd_energy_probe(struct platform_device *pdev)
mutex_init(&data->lock);
get_energy_units(data);

- hwmon_dev = devm_hwmon_device_register_with_info(dev, DRVNAME,
- data,
- &data->chip,
- NULL);
- if (IS_ERR(hwmon_dev))
- return PTR_ERR(hwmon_dev);
+ data->hwmon_dev = devm_hwmon_device_register_with_info(dev, DRVNAME,
+ data,
+ &data->chip,
+ NULL);
+ if (IS_ERR(data->hwmon_dev))
+ return PTR_ERR(data->hwmon_dev);

/* Once in 3 minutes for a resolution of 1/2*16 */
if (data->energy_units == 0x10)
@@ -305,10 +369,12 @@ static int amd_energy_probe(struct platform_device *pdev)
if (data->energy_units == 0x6)
data->timeout = 3 * 24 * 60 * 60;

- data->wrap_accumulate = kthread_run(energy_accumulator, data,
- "%s", dev_name(hwmon_dev));
- if (IS_ERR(data->wrap_accumulate))
- return PTR_ERR(data->wrap_accumulate);
+ /* Disabling the energy accumulation by default */
+ data->accumulator_status = 0;
+
+ ret = create_accumulate_status_file(data);
+ if (ret)
+ return ret;

return 0;
}
@@ -317,6 +383,8 @@ static int amd_energy_remove(struct platform_device *pdev)
{
struct amd_energy_data *data = dev_get_drvdata(&pdev->dev);

+ sysfs_remove_file(&data->hwmon_dev->kobj, &accumulate_attr.attr);
+
if (data && data->wrap_accumulate)
kthread_stop(data->wrap_accumulate);

--
2.26.2