Re: [PATCH v3 2/3] hwmon: ibmpowernv: Add attributes to enable/disable sensor groups

From: Shilpasri G Bhat
Date: Thu Jul 05 2018 - 13:35:58 EST

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In reply to: Guenter Roeck: "Re: [PATCH v3 2/3] hwmon: ibmpowernv: Add attributes to enable/disable sensor groups"
Next in thread: Shilpasri G Bhat: "[PATCH v3 3/3] hwmon: Document the sensor enable attribute and update ibmpowernv"
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Hi,

On 07/05/2018 09:07 PM, Guenter Roeck wrote:
> On 07/05/2018 06:51 AM, Shilpasri G Bhat wrote:
>> On-Chip-Controller(OCC) is an embedded micro-processor in POWER9 chip
>> which measures various system and chip level sensors. These sensors
>> comprises of environmental sensors (like power, temperature, current
>> and voltage) and performance sensors (like utilization, frequency).
>> All these sensors are copied to main memory at a regular interval of
>> 100ms. OCC provides a way to select a group of sensors that is copied
>> to the main memory to increase the update frequency of selected sensor
>> groups. When a sensor-group is disabled, OCC will not copy it to main
>> memory and those sensors read 0 values.
>>
>> This patch provides support for enabling/disabling the sensor groups
>> like power, temperature, current and voltage. This patch adds new
>> per-senor sysfs attribute to disable and enable them.
>>
>> Signed-off-by: Shilpasri G Bhat <shilpa.bhat@xxxxxxxxxxxxxxxxxx>
>> ---
>> Changes from v2:
>> - Writes to first 'enable' attribute of the sensor group will affect all the
>> sensors in the group
>> - Removed global mutex and made it per sensor-group
>>
>> drivers/hwmon/ibmpowernv.c | 184 ++++++++++++++++++++++++++++++++++++++-------
>> 1 file changed, 155 insertions(+), 29 deletions(-)
>>
>> diff --git a/drivers/hwmon/ibmpowernv.c b/drivers/hwmon/ibmpowernv.c
>> index f829dad..9c6adee 100644
>> --- a/drivers/hwmon/ibmpowernv.c
>> +++ b/drivers/hwmon/ibmpowernv.c
>> @@ -73,6 +73,10 @@ enum sensors {
>> struct attribute_group group;
>> u32 attr_count;
>> u32 hwmon_index;
>> + struct mutex mutex;
>> + u32 *gid;
>> + u32 nr_gid;
>> + bool enable;
>> } sensor_groups[] = {
>> { "fan" },
>> { "temp" },
>> @@ -105,6 +109,9 @@ static ssize_t show_sensor(struct device *dev, struct
>> device_attribute *devattr,
>> ssize_t ret;
>> u64 x;
>> + if (!sensor_groups[sdata->type].enable)
>> + return -ENODATA;
>> +
>> ret = opal_get_sensor_data_u64(sdata->id, &x);
>> if (ret)
>> @@ -120,6 +127,46 @@ static ssize_t show_sensor(struct device *dev, struct
>> device_attribute *devattr,
>> return sprintf(buf, "%llu\n", x);
>> }
>> +static ssize_t show_enable(struct device *dev,
>> + struct device_attribute *devattr, char *buf)
>> +{
>> + struct sensor_data *sdata = container_of(devattr, struct sensor_data,
>> + dev_attr);
>> +
>> + return sprintf(buf, "%u\n", sensor_groups[sdata->type].enable);
>> +}
>> +
>> +static ssize_t store_enable(struct device *dev,
>> + struct device_attribute *devattr,
>> + const char *buf, size_t count)
>> +{
>> + struct sensor_data *sdata = container_of(devattr, struct sensor_data,
>> + dev_attr);
>> + struct sensor_group *sg = &sensor_groups[sdata->type];
>> + int ret, i;
>> + bool data;
>> +
>> + ret = kstrtobool(buf, &data);
>> + if (ret)
>> + return ret;
>> +
>> + ret = mutex_lock_interruptible(&sg->mutex);
>> + if (ret)
>> + return ret;
>> +
>> + if (data != sg->enable)
>> + for (i = 0; i < sg->nr_gid && !ret; i++)
>> + ret = sensor_group_enable(sg->gid[i], data);
>> +
>
> Wouldn't it be better to have a separate attribute for each of the
> affected groups if there can be more than one ? Just wondering.
>
> The idea was to widen the scope to a point where there is a 1:1 match
> between the hardware capabilities and attributes. Clearly having
> a separate attribute for all sensors was inappropriate, but the code
> above now suggests that a single attribute for all sensors may have
> widened the scope too much (because the hardware can do better than
> this).
>

Yup it would be better to have 'enable' attribute for each sub-group.

Thanks and Regards,
Shilpa

> Thanks,
> Guenter
>
>> + if (!ret) {
>> + sg->enable = data;
>> + ret = count;
>> + }
>> +
>> + mutex_unlock(&sg->mutex);
>> + return ret;
>> +}
>> +
>> static ssize_t show_label(struct device *dev, struct device_attribute *devattr,
>> char *buf)
>> {
>> @@ -292,13 +339,68 @@ static u32 get_sensor_hwmon_index(struct sensor_data
>> *sdata,
>> return ++sensor_groups[sdata->type].hwmon_index;
>> }
>> +static int init_sensor_group_data(struct platform_device *pdev)
>> +{
>> + struct device_node *groups, *sg;
>> + enum sensors type;
>> + int ret = 0, i;
>> +
>> + for (i = 0; i < MAX_SENSOR_TYPE; i++) {
>> + sensor_groups[i].nr_gid = 0;
>> + sensor_groups[i].enable = true;
>> + }
>> +
>> + groups = of_find_node_by_path("/ibm,opal/sensor-groups");
>> + if (!groups)
>> + return ret;
>> +
>> + for (i = 0; i < MAX_SENSOR_TYPE; i++) {
>> + u32 gid[256];
>> + u32 id, size;
>> +
>> + for_each_child_of_node(groups, sg) {
>> + type = get_sensor_type(sg);
>> + if (type != i)
>> + continue;
>> +
>> + if (of_property_read_u32(sg, "sensor-group-id", &id))
>> + continue;
>> +
>> + gid[sensor_groups[i].nr_gid++] = id;
>> + }
>> +
>> + if (!sensor_groups[i].nr_gid)
>> + continue;
>> +
>> + size = sensor_groups[i].nr_gid * sizeof(u32);
>> + sensor_groups[i].gid = devm_kzalloc(&pdev->dev, size,
>> + GFP_KERNEL);
>> + if (!sensor_groups[i].gid) {
>> + ret = -ENOMEM;
>> + break;
>> + }
>> +
>> + memcpy(sensor_groups[i].gid, gid, size);
>> + sensor_groups[i].enable = false;
>> + mutex_init(&sensor_groups[i].mutex);
>> + }
>> +
>> + of_node_put(groups);
>> + return ret;
>> +}
>> +
>> static int populate_attr_groups(struct platform_device *pdev)
>> {
>> struct platform_data *pdata = platform_get_drvdata(pdev);
>> const struct attribute_group **pgroups = pdata->attr_groups;
>> struct device_node *opal, *np;
>> + int ret;
>> enum sensors type;
>> + ret = init_sensor_group_data(pdev);
>> + if (ret)
>> + return ret;
>> +
>> opal = of_find_node_by_path("/ibm,opal/sensors");
>> for_each_child_of_node(opal, np) {
>> const char *label;
>> @@ -313,7 +415,7 @@ static int populate_attr_groups(struct platform_device *pdev)
>> sensor_groups[type].attr_count++;
>> /*
>> - * add attributes for labels, min and max
>> + * add attributes for labels, min, max and enable
>> */
>> if (!of_property_read_string(np, "label", &label))
>> sensor_groups[type].attr_count++;
>> @@ -321,6 +423,8 @@ static int populate_attr_groups(struct platform_device *pdev)
>> sensor_groups[type].attr_count++;
>> if (of_find_property(np, "sensor-data-max", NULL))
>> sensor_groups[type].attr_count++;
>> + if (sensor_groups[type].nr_gid)
>> + sensor_groups[type].attr_count++;
>> }
>> of_node_put(opal);
>> @@ -344,7 +448,10 @@ static int populate_attr_groups(struct platform_device
>> *pdev)
>> static void create_hwmon_attr(struct sensor_data *sdata, const char *attr_name,
>> ssize_t (*show)(struct device *dev,
>> struct device_attribute *attr,
>> - char *buf))
>> + char *buf),
>> + ssize_t (*store)(struct device *dev,
>> + struct device_attribute *attr,
>> + const char *buf, size_t count))
>> {
>> snprintf(sdata->name, MAX_ATTR_LEN, "%s%d_%s",
>> sensor_groups[sdata->type].name, sdata->hwmon_index,
>> @@ -352,8 +459,13 @@ static void create_hwmon_attr(struct sensor_data *sdata,
>> const char *attr_name,
>> sysfs_attr_init(&sdata->dev_attr.attr);
>> sdata->dev_attr.attr.name = sdata->name;
>> - sdata->dev_attr.attr.mode = S_IRUGO;
>> sdata->dev_attr.show = show;
>> + if (store) {
>> + sdata->dev_attr.store = store;
>> + sdata->dev_attr.attr.mode = 0664;
>> + } else {
>> + sdata->dev_attr.attr.mode = 0444;
>> + }
>> }
>> static void populate_sensor(struct sensor_data *sdata, int od, int hd, int
>> sid,
>> @@ -361,13 +473,16 @@ static void populate_sensor(struct sensor_data *sdata,
>> int od, int hd, int sid,
>> const struct attribute_group *pgroup,
>> ssize_t (*show)(struct device *dev,
>> struct device_attribute *attr,
>> - char *buf))
>> + char *buf),
>> + ssize_t (*store)(struct device *dev,
>> + struct device_attribute *attr,
>> + const char *buf, size_t count))
>> {
>> sdata->id = sid;
>> sdata->type = type;
>> sdata->opal_index = od;
>> sdata->hwmon_index = hd;
>> - create_hwmon_attr(sdata, attr_name, show);
>> + create_hwmon_attr(sdata, attr_name, show, store);
>> pgroup->attrs[sensor_groups[type].attr_count++] = &sdata->dev_attr.attr;
>> }
>> @@ -408,18 +523,16 @@ static int create_device_attrs(struct platform_device
>> *pdev)
>> u32 count = 0;
>> int err = 0;
>> - opal = of_find_node_by_path("/ibm,opal/sensors");
>> sdata = devm_kcalloc(&pdev->dev,
>> pdata->sensors_count, sizeof(*sdata),
>> GFP_KERNEL);
>> - if (!sdata) {
>> - err = -ENOMEM;
>> - goto exit_put_node;
>> - }
>> + if (!sdata)
>> + return -ENOMEM;
>> + opal = of_find_node_by_path("/ibm,opal/sensors");
>> for_each_child_of_node(opal, np) {
>> const char *attr_name;
>> - u32 opal_index;
>> + u32 opal_index, hw_id;
>> const char *label;
>> if (np->name == NULL)
>> @@ -456,14 +569,11 @@ static int create_device_attrs(struct platform_device
>> *pdev)
>> opal_index = INVALID_INDEX;
>> }
>> - sdata[count].opal_index = opal_index;
>> - sdata[count].hwmon_index =
>> - get_sensor_hwmon_index(&sdata[count], sdata, count);
>> -
>> - create_hwmon_attr(&sdata[count], attr_name, show_sensor);
>> -
>> - pgroups[type]->attrs[sensor_groups[type].attr_count++] =
>> - &sdata[count++].dev_attr.attr;
>> + hw_id = get_sensor_hwmon_index(&sdata[count], sdata, count);
>> + populate_sensor(&sdata[count], opal_index, hw_id, sensor_id,
>> + attr_name, type, pgroups[type], show_sensor,
>> + NULL);
>> + count++;
>> if (!of_property_read_string(np, "label", &label)) {
>> /*
>> @@ -474,33 +584,49 @@ static int create_device_attrs(struct platform_device
>> *pdev)
>> */
>> make_sensor_label(np, &sdata[count], label);
>> - populate_sensor(&sdata[count], opal_index,
>> - sdata[count - 1].hwmon_index,
>> + populate_sensor(&sdata[count], opal_index, hw_id,
>> sensor_id, "label", type, pgroups[type],
>> - show_label);
>> + show_label, NULL);
>> count++;
>> }
>> if (!of_property_read_u32(np, "sensor-data-max", &sensor_id)) {
>> attr_name = get_max_attr(type);
>> - populate_sensor(&sdata[count], opal_index,
>> - sdata[count - 1].hwmon_index,
>> + populate_sensor(&sdata[count], opal_index, hw_id,
>> sensor_id, attr_name, type,
>> - pgroups[type], show_sensor);
>> + pgroups[type], show_sensor, NULL);
>> count++;
>> }
>> if (!of_property_read_u32(np, "sensor-data-min", &sensor_id)) {
>> attr_name = get_min_attr(type);
>> - populate_sensor(&sdata[count], opal_index,
>> - sdata[count - 1].hwmon_index,
>> + populate_sensor(&sdata[count], opal_index, hw_id,
>> sensor_id, attr_name, type,
>> - pgroups[type], show_sensor);
>> + pgroups[type], show_sensor, NULL);
>> count++;
>> }
>> +
>> + if (sensor_groups[type].nr_gid) {
>> + ssize_t (*store)(struct device *dev,
>> + struct device_attribute *attr,
>> + const char *buf, size_t count);
>> +
>> + if (!sensor_groups[type].enable) {
>> + sensor_groups[type].enable = true;
>> + store = store_enable;
>> + } else {
>> + store = NULL;
>> + }
>> +
>> + sensor_groups[type].enable = true;
>> + populate_sensor(&sdata[count], opal_index, hw_id,
>> + sensor_id, "enable", type,
>> + pgroups[type], show_enable, store);
>> + count++;
>> + }
>> +
>> }
>> -exit_put_node:
>> of_node_put(opal);
>> return err;
>> }
>>
>

Next message: Eric W. Biederman: "Re: [PATCH] Revert "vfs: Allow userns root to call mknod on owned filesystems.""
Previous message: Christian Brauner: "Re: [PATCH] Revert "vfs: Allow userns root to call mknod on owned filesystems.""
In reply to: Guenter Roeck: "Re: [PATCH v3 2/3] hwmon: ibmpowernv: Add attributes to enable/disable sensor groups"
Next in thread: Shilpasri G Bhat: "[PATCH v3 3/3] hwmon: Document the sensor enable attribute and update ibmpowernv"
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