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Message-ID: <9b55f78a-1d29-4391-c43e-124772b7aa9f@roeck-us.net>
Date: Thu, 5 Jul 2018 08:37:33 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Shilpasri G Bhat <shilpa.bhat@...ux.vnet.ibm.com>,
mpe@...erman.id.au, linuxppc-dev@...ts.ozlabs.org,
linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org,
ego@...ux.vnet.ibm.com
Subject: Re: [PATCH v3 2/3] hwmon: ibmpowernv: Add attributes to
enable/disable sensor groups
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@...ux.vnet.ibm.com>
> ---
> 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).
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;
> }
>
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