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Message-ID: <e3a013fb-eaf0-8d45-2f23-3be8b3e5640b@roeck-us.net>
Date: Wed, 4 Jul 2018 07:46:32 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Shilpasri G Bhat <shilpa.bhat@...ux.vnet.ibm.com>,
mpe@...erman.id.au
Cc: linuxppc-dev@...ts.ozlabs.org, linux-hwmon@...r.kernel.org,
linux-kernel@...r.kernel.org, ego@...ux.vnet.ibm.com
Subject: Re: [PATCH v2 2/2] hwmon: ibmpowernv: Add attributes to
enable/disable sensor groups
On 07/04/2018 02:16 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 v1:
> - Add per-sensor 'enable' attribute
> - Return -ENODATA when sensor is disabled
>
> Documentation/hwmon/sysfs-interface | 22 +++
> drivers/hwmon/ibmpowernv.c | 281 +++++++++++++++++++++++++++++++-----
> 2 files changed, 264 insertions(+), 39 deletions(-)
>
> diff --git a/Documentation/hwmon/sysfs-interface b/Documentation/hwmon/sysfs-interface
> index fc337c3..38ab05c 100644
> --- a/Documentation/hwmon/sysfs-interface
> +++ b/Documentation/hwmon/sysfs-interface
Separate patch please.
> @@ -184,6 +184,11 @@ vrm Voltage Regulator Module version number.
> Affects the way the driver calculates the CPU core reference
> voltage from the vid pins.
>
> +in[0-*]_enable Enable or disable the sensor
> + 1 : Enable
> + 0 : Disable
> + RW
> +
> Also see the Alarms section for status flags associated with voltages.
>
>
> @@ -409,6 +414,12 @@ temp_reset_history
> Reset temp_lowest and temp_highest for all sensors
> WO
>
> +temp[1-*]_enable
> + Enable or disable the sensor
> + 1 : Enable
> + 0 : Disable > + RW
> +
> Some chips measure temperature using external thermistors and an ADC, and
> report the temperature measurement as a voltage. Converting this voltage
> back to a temperature (or the other way around for limits) requires
> @@ -468,6 +479,12 @@ curr_reset_history
> Reset currX_lowest and currX_highest for all sensors
> WO
>
> +curr[1-*]_enable
> + Enable or disable the sensor
> + 1 : Enable
> + 0 : Disable
> + RW
> +
> Also see the Alarms section for status flags associated with currents.
>
> *********
> @@ -566,6 +583,11 @@ power[1-*]_crit Critical maximum power.
> Unit: microWatt
> RW
>
> +power[1-*]_enable Enable or disable the sensor
> + 1 : Enable
> + 0 : Disable
> + RW
> +
> Also see the Alarms section for status flags associated with power readings.
>
Any reason for excluding fan, energy, humidity ?
> **********
> diff --git a/drivers/hwmon/ibmpowernv.c b/drivers/hwmon/ibmpowernv.c
> index f829dad..61e04cf 100644
> --- a/drivers/hwmon/ibmpowernv.c
> +++ b/drivers/hwmon/ibmpowernv.c
> @@ -90,8 +90,28 @@ struct sensor_data {
> char label[MAX_LABEL_LEN];
> char name[MAX_ATTR_LEN];
> struct device_attribute dev_attr;
> + struct sensor_group_data *sgdata;
> + struct sensor_data *sdata[3];
> + bool enable;
> };
>
> +static struct sensor_group_data {
> + u32 gid;
> + u32 nr_phandle;
> + u32 nr_sensor;
> + enum sensors type;
> + const __be32 *phandles;
> + struct sensor_data **sensors;
> + bool enable;
> +} *sg_data;
> +
> +/*
> + * To synchronise writes to struct sensor_data.enable and
> + * struct sensor_group_data.enable
> + */
> +DEFINE_MUTEX(sensor_groups_mutex);
Not as global variable, please.
> +static int nr_sensor_groups;
> +
Do those have to be static variables ? Why not in struct platform_data ?
> struct platform_data {
> const struct attribute_group *attr_groups[MAX_SENSOR_TYPE + 1];
> u32 sensors_count; /* Total count of sensors from each group */
> @@ -105,6 +125,9 @@ static ssize_t show_sensor(struct device *dev, struct device_attribute *devattr,
> ssize_t ret;
> u64 x;
>
> + if (sdata->sgdata && !sdata->enable)
> + return -ENODATA;
> +
This return code should be documented in the ABI.
> ret = opal_get_sensor_data_u64(sdata->id, &x);
>
> if (ret)
> @@ -120,6 +143,74 @@ 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", sdata->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_data *sg = sdata->sgdata;
> + u32 data;
> + int ret, i;
> + bool send_command;
> +
> + ret = kstrtoint(buf, 0, &data);
Use kstrtobool(), please. Then you won't need the additional range check below.
> + if (ret)
> + return ret;
> +
> + if (data != 0 && data != 1)
> + return -EIO;
This is not an IO error.
> +
> + ret = mutex_lock_interruptible(&sensor_groups_mutex);
> + if (ret)
> + return ret;
> +
> + sdata->enable = data;
> + if ((data && sg->enable) || (!data && !sg->enable)) {
> + send_command = false;
If data is bool you can use a simple comparison.
> + } else if (data && !sg->enable) {
!sg->enable is unnecessary.
> + /* Enable if first sensor in the group */
> + send_command = true; > + } else if (!data && sg->enable) {
This if statement is always true and thus unnecessary.
Overall, you could use
send_command = data != sg->enable;
if (send_command && !data) {
for (...) {
> + /* Disable if last sensor in the group */
> + send_command = true;
> + for (i = 0; i < sg->nr_sensor; i++) {
> + struct sensor_data *sd = sg->sensors[i];
> +
> + if (sd->enable) {
> + send_command = false;
> + break;
> + }
This is weird. So there are situations where a request to disable
a sensor is accepted, but effectively ignored ? Shouldn't that
return, say, -EBUSY ?
> + }
> + }
> +
> + if (send_command) {
> + ret = sensor_group_enable(sg->gid, data);
> + if (!ret)
> + sg->enable = data;
> + }
> +
> + if (!ret) {
> + for (i = 0; i < ARRAY_SIZE(sdata->sdata); i++)
> + sdata->sdata[i]->enable = data;
> + ret = count;
> + } else {
> + ret = -EIO;
No overriding error codes, please.
> + }
> +
> + mutex_unlock(&sensor_groups_mutex);
> + return ret;
> +}
> +
> static ssize_t show_label(struct device *dev, struct device_attribute *devattr,
> char *buf)
> {
> @@ -292,6 +383,90 @@ 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 *sensor_groups, *sg;
> + enum sensors type;
> + int count = 0, ret = 0;
> +
> + sensor_groups = of_find_node_by_path("/ibm,opal/sensor-groups");
> + if (!sensor_groups)
> + return ret;
> +
> + for_each_child_of_node(sensor_groups, sg) {
> + type = get_sensor_type(sg);
> + if (type != MAX_SENSOR_TYPE)
> + nr_sensor_groups++;
> + }
> +
> + if (!nr_sensor_groups)
> + goto out;
> +
> + sg_data = devm_kzalloc(&pdev->dev, nr_sensor_groups * sizeof(*sg_data),
> + GFP_KERNEL);
> + if (!sg_data) {
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> + for_each_child_of_node(sensor_groups, sg) {
> + const __be32 *phandles;
> + int len, gid;
> +
> + type = get_sensor_type(sg);
> + if (type == MAX_SENSOR_TYPE)
> + continue;
> +
> + if (of_property_read_u32(sg, "sensor-group-id", &gid))
> + continue;
> +
> + phandles = of_get_property(sg, "sensors", &len);
> + if (!phandles)
> + continue;
> +
> + len /= sizeof(u32);
> + if (!len)
> + continue;
> +
> + sg_data[count].sensors = devm_kzalloc(&pdev->dev,
> + len * sizeof(struct sensor_data *),
> + GFP_KERNEL);
> + if (!sg_data[count].sensors) {
> + ret = -ENOMEM;
> + break;
Doesn't this result in a missing of_node_put() on sg ?
> + }
> +
> + sg_data[count].nr_sensor = 0;
> + sg_data[count].gid = gid;
> + sg_data[count].type = type;
> + sg_data[count].nr_phandle = len;
> + sg_data[count].phandles = phandles;
> + sg_data[count++].enable = true;
> + }
> +out:
> + of_node_put(sensor_groups);
> + return ret;
> +}
> +
> +static struct sensor_group_data *get_sensor_group(struct device_node *np,
> + enum sensors type)
> +{
> + int i, j;
> +
> + for (i = 0; i < nr_sensor_groups; i++) {
> + const __be32 *phandles = sg_data[i].phandles;
> +
> + if (type != sg_data[i].type)
> + continue;
> +
> + for (j = 0; j < sg_data[i].nr_phandle; j++)
> + if (be32_to_cpu(phandles[j]) == np->phandle)
> + return &sg_data[i];
> + }
> +
> + return NULL;
> +}
> +
> static int populate_attr_groups(struct platform_device *pdev)
> {
> struct platform_data *pdata = platform_get_drvdata(pdev);
> @@ -299,6 +474,9 @@ static int populate_attr_groups(struct platform_device *pdev)
> struct device_node *opal, *np;
> enum sensors type;
>
> + if (init_sensor_group_data(pdev))
> + return -ENOMEM;
> +
init_sensor_group_data() returns an error code which you should pass on.
> opal = of_find_node_by_path("/ibm,opal/sensors");
> for_each_child_of_node(opal, np) {
> const char *label;
> @@ -313,7 +491,7 @@ 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 +499,8 @@ 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 (get_sensor_group(np, type))
> + sensor_groups[type].attr_count++;
> }
>
> of_node_put(opal);
> @@ -344,7 +524,10 @@ 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,
> @@ -352,23 +535,34 @@ 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,
> const char *attr_name, enum sensors type,
> const struct attribute_group *pgroup,
> + struct sensor_group_data *sgdata,
> 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;
> + sdata->enable = true;
> + sdata->sgdata = sgdata;
> }
>
> static char *get_max_attr(enum sensors type)
> @@ -408,18 +602,17 @@ 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) {
> + struct sensor_group_data *sgdata;
> const char *attr_name;
> - u32 opal_index;
> + u32 opal_index, hw_id;
> const char *label;
>
> if (np->name == NULL)
> @@ -456,14 +649,43 @@ 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);
> + hw_id = get_sensor_hwmon_index(&sdata[count], sdata, count);
> + sgdata = get_sensor_group(np, type);
> + populate_sensor(&sdata[count], opal_index, hw_id, sensor_id,
> + attr_name, type, pgroups[type], sgdata,
> + show_sensor, 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, hw_id,
> + sensor_id, attr_name, type,
> + pgroups[type], sgdata, 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, hw_id,
> + sensor_id, attr_name, type,
> + pgroups[type], sgdata, show_sensor,
> + NULL);
> + count++;
> + }
>
> - create_hwmon_attr(&sdata[count], attr_name, show_sensor);
> + if (sgdata) {
> + int i;
>
> - pgroups[type]->attrs[sensor_groups[type].attr_count++] =
> - &sdata[count++].dev_attr.attr;
> + sgdata->sensors[sgdata->nr_sensor++] = &sdata[count];
> + populate_sensor(&sdata[count], opal_index, hw_id,
> + sgdata->gid, "enable", type,
> + pgroups[type], sgdata, show_enable,
> + store_enable);
> + for (i = 0; i < ARRAY_SIZE(sdata[count].sdata); i++)
> + sdata[count].sdata[i] = &sdata[count - i - 1];
> + count++;
> + }
>
> if (!of_property_read_string(np, "label", &label)) {
> /*
> @@ -474,34 +696,15 @@ 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);
> - 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,
> - sensor_id, attr_name, type,
> - pgroups[type], show_sensor);
> - 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,
> - sensor_id, attr_name, type,
> - pgroups[type], show_sensor);
> + NULL, show_label, NULL);
> count++;
> }
> }
>
> -exit_put_node:
> of_node_put(opal);
> +
> return err;
> }
>
>
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