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SYSMON_ENVSYS(9) Kernel Developer's Manual SYSMON_ENVSYS(9)
NAME
sysmon_envsys - kernel part of the envsys 2 framework
SYNOPSIS
#include <dev/sysmon/sysmonvar.h>
struct sysmon_envsys *
sysmon_envsys_create(void);
void
sysmon_envsys_destroy(struct sysmon_envsys *);
int
sysmon_envsys_register(struct sysmon_envsys *);
void
sysmon_envsys_unregister(struct sysmon_envsys *);
int
sysmon_envsys_sensor_attach(struct sysmon_envsys *, envsys_data_t *);
int
sysmon_envsys_sensor_detach(struct sysmon_envsys *, envsys_data_t *);
void
sysmon_envsys_sensor_event(struct sysmon_envsys *, envsys_data_t *, int);
void
sysmon_envsys_foreach_sensor(sysmon_envsys_callback_t, void *, bool);
int
sysmon_envsys_update_limits(struct sysmon_envsys *, envsys_data_t *);
DESCRIPTION
sysmon_envsys is the kernel part of the envsys(4) framework. With this
framework you are able to register and unregister a sysmon_envsys device,
attach or detach sensors into a device, and enable or disable automatic
monitoring for some sensors without any user interactivity, among other
things.
HOW TO USE THE FRAMEWORK
To register a new driver to the sysmon_envsys framework, a sysmon_envsys
object must be allocated and initialized; the sysmon_envsys_create()
function is used for this. This returns a zero'ed pointer to a
sysmon_envsys structure.
Once the object has been initialized, actual sensors may be initialized
and attached (see the SENSOR DETAILS section for more information). This
is accomplished by the sysmon_envsys_sensor_attach() function, which will
attach the envsys_data_t (a sensor) specified as second argument into the
sysmon_envsys object specified in the first argument.
Finally, after all sensors have been attached, the device needs to set
some required (and optional) members of the sysmon_envsys structure
before calling the sysmon_envsys_register() function to register the
device.
In case of errors during the initialization, the sysmon_envsys_destroy()
function should be used. This detaches all previously attached sensors
and deallocates the sysmon_envsys object.
Some sensors can be monitored, and when the sensor value changes an event
can be delivered to the powerd(8) daemon. Sensor monitoring can be
performed by the sysmon_envsys framework on a polled basis.
Alternatively, the sensor's device driver can call the
sysmon_envsys_sensor_event() function to deliver the event without
waiting for the device to be polled.
The sysmon_envsys_foreach_sensor() function can be used by other parts of
the kernel to iterate over all registered sensors. This capability is
used by the i386/apm(4) driver to summarize the state of all battery
sensors.
Drivers can also call the sysmon_envsys_update_limits() function when it
is necessary to reinitialize a sensor's threshold values. This is used
by the acpibat(4) driver when a new battery is inserted.
The sysmon_envsys structure is defined as follows (only the public
members are shown):
struct sysmon_envsys {
const char *sme_name;
int sme_flags;
int sme_class;
uint64_t sme_events_timeout;
void *sme_cookie;
void (*sme_refresh)(struct sysmon_envsys *, envsys_data_t *);
void (*sme_set_limits)(struct sysmon_envsys *, envsys_data_t *,
sysmon_envsys_lim_t *, uint32_t *);
void (*sme_get_limits)(struct sysmon_envsys *, envsys_data_t *,
sysmon_envsys_lim_t *, uint32_t *);
};
The members have the following meaning:
sme_class This specifies the class of the sysmon envsys device.
See the DEVICE CLASSES section for more information
(OPTIONAL).
sme_name The name that will be used in the driver (REQUIRED).
sme_flags Additional flags for the sysmon_envsys device.
Currently supporting SME_DISABLE_REFRESH. If
enabled, the sme_refresh function callback won't be
used to refresh sensor data and the driver will use
its own method (OPTIONAL).
sme_events_timeout This is used to specify the default timeout value (in
seconds) that will be used to check for critical
events if any monitoring flag was set (OPTIONAL).
If the driver wants to refresh sensors data via the sysmon_envsys
framework, the following members may be specified:
sme_cookie Typically a pointer to the device struct (also called
"softc"). This may be used in the sme_refresh,
sme_get_limits, or sme_set_limits function callbacks.
sme_refresh Pointer to a function that will be used to refresh
sensor data in the device. This can be used to set
the state and other properties of the sensor
depending on the data returned by the driver. NOTE:
You don't have to refresh all sensors, only the
sensor specified by the edata->sensor index. If this
member is not specified, the device driver will be
totally responsible for all updates of this sensor;
the sysmon_envsys framework will not be able to
update the sensor value.
sme_get_limits Pointer to a function that will be used to obtain
from the driver the initial limits (or thresholds)
used when monitoring a sensor's value. (See the
SENSOR DETAILS section for more information.) If
this member is not specified, the ENVSYS_FMONLIMITS
flag will be ignored, and limit monitoring will not
occur until appropriate limits are enabled from
userland via envstat(8).
sme_set_limits Pointer to a function that alerts the device driver
whenever monitoring limits (or thresholds) are
updated by the user. Setting this function allows
the device driver to reprogram hardware limits (if
provided by the device) when the user-specificied
limits are updated, and gives the driver direct
control over setting the sensor's state based on
hardware status.
The sme_set_limits callback can be invoked with the
third argument (a pointer to the new limits) set to a
NULL pointer. Device drivers must recognize this as
a request to restore the sensor limits to their
original, boot-time values.
If the sme_set_limits member is not specified, the
device driver is not informed of changes to the
sensor's limit values, and the sysmon_envsys
framework performs all limit checks in software.
Note that it's not necessary to refresh the sensors data before the
driver is registered, only do it if you need the data in your driver to
check for a specific condition.
The timeout value for the monitoring events on a device may be changed
via the ENVSYS_SETDICTIONARY ioctl(2) or the envstat(8) command.
To unregister a driver previously registered with the sysmon_envsys
framework, the sysmon_envsys_unregister() function must be used. If
there were monitoring events registered for the driver, they all will be
destroyed before the device is unregistered and its sensors are detached.
Finally the sysmon_envsys object will be freed, so there's no need to
call sysmon_envsys_destroy().
DEVICE CLASSES
The sme_class member of the sysmon_envsys structure is an optional flag
that specifies the class of the sysmon envsys device. Currently there
are two classes:
SME_CLASS_ACADAPTER
This class is for devices that want to act as an AC adapter. The
device writer must ensure that at least there is a sensor with
units of ENVSYS_INDICATOR. This will be used to report its
current state (on/off).
SME_CLASS_BATTERY
This class is for devices that want to act as a Battery. The
device writer must ensure that at least there are two sensors with
units of ENVSYS_BATTERY_CAPACITY and ENVSYS_BATTERY_CHARGE.
These two sensors are used to ensure that the battery device can
send a low-power event to the powerd(8) daemon (if running) when
all battery devices are in a critical state. (The critical state
occurs when a battery is not currently charging and its charge
state is low or critical.) When the low-power condition is met,
an event is sent to the powerd(8) daemon (if running), which will
shutdown the system gracefully by executing the
/etc/powerd/scripts/sensor_battery script.
If powerd(8) is not running, the system will be powered off via
the cpu_reboot(9) call with the RB_POWERDOWN flag.
NOTE: If a SME_CLASS_ACADAPTER or SME_CLASS_BATTERY class device doesn't
have the sensors required, the low-power event will never be sent, and
the graceful shutdown won't be possible.
SENSOR DETAILS
Each sensor uses a envsys_data_t structure, it's defined as follows (only
the public members are shown);
typedef struct envsys_data {
uint32_t units;
uint32_t state;
uint32_t flags;
uint32_t rpms;
int32_t rfact;
int32_t value_cur;
int32_t value_max;
int32_t value_min;
int32_t value_avg;
sysmon_envsys_lim_t limits;
int upropset;
char desc[ENVSYS_DESCLEN];
} envsys_data_t;
The members for the envsys_data_t structure have the following meaning:
units Used to set the units type.
state Used to set the current state.
flags Used to set additional flags. Among other uses, if one or
more of the ENVSYS_FMONxxx flags are set, automatic sensor
monitoring will be enabled. Periodically, the sensor's
value will be checked and if certain conditions are met,
an event will be sent to the powerd(8) daemon. NOTE that
limits (or thresholds) can be set at any time to enable
monitoring that the sensor's value remains within those
limits.
rpms Used to set the nominal RPM value for fan sensors.
rfact Used to set the rfact value for voltage sensors.
value_cur Used to set the current value.
value_max Used to set the maximum value.
value_min Used to set the minimum value.
value_avg Used to set the average value.
limits Structure used to contain the sensor's alarm thresholds.
upropset Used to keep track of which sensor properties are set.
desc Used to set the description string. NOTE that the
description string must be unique in a device, and sensors
with duplicate or empty description will simply be
ignored.
Users of this framework must take care about the following points:
⊕ The desc member needs to have a valid description, unique in a device
and non empty to be valid.
⊕ The units type must be valid. The following units are defined:
ENVSYS_STEMP For temperature sensors, in microkelvins.
ENVSYS_SFANRPM For fan sensors.
ENVSYS_SVOLTS_AC For AC Voltage.
ENVSYS_SVOLTS_DC For DC Voltage.
ENVSYS_SOHMS For Ohms.
ENVSYS_SWATTS For Watts.
ENVSYS_SAMPS For Ampere.
ENVSYS_SWATTHOUR For Watts hour.
ENVSYS_SAMPHOUR For Ampere hour.
ENVSYS_INDICATOR For sensors that only want a boolean type.
ENVSYS_INTEGER For sensors that only want an integer type.
ENVSYS_DRIVE For drive sensors.
ENVSYS_BATTERY_CAPACITY For Battery device classes. This sensor
unit uses the ENVSYS_BATTERY_CAPACITY_*
values in value_cur to report its current
capacity to userland. Mandatory if
sme_class is set to SME_CLASS_BATTERY.
ENVSYS_BATTERY_CHARGE For Battery device classes. This sensor is
equivalent to the Indicator type, it's a
boolean. Use it to specify in what state is
the Battery state: true if the battery is
currently charging or false otherwise.
Mandatory if sme_class is set to
SME_CLASS_BATTERY.
⊕ When initializing or refreshing the sensor, the state member should
be set to a known state (otherwise it will be in unknown state).
Possible values:
ENVSYS_SVALID Sets the sensor to a valid state.
ENVSYS_SINVALID Sets the sensor to an invalid state.
ENVSYS_SCRITICAL Sets the sensor to a critical state.
ENVSYS_SCRITUNDER Sets the sensor to a critical under state.
ENVSYS_SCRITOVER Sets the sensor to a critical over state.
ENVSYS_SWARNUNDER Sets the sensor to a warning under state.
ENVSYS_SWARNOVER Sets the sensor to a warning over state.
⊕ The flags member accepts one or more of the following flags:
ENVSYS_FCHANGERFACT Marks the sensor with ability to change the
rfact value on the fly (in voltage sensors).
The rfact member must be used in the correct
place of the code that retrieves and converts
the value of the sensor.
ENVSYS_FPERCENT This uses the value_cur and value_max members
to make a percentage. Both values must be
enabled and have data.
ENVSYS_FVALID_MAX Marks the value_max value as valid.
ENVSYS_FVALID_MIN Marks the value_min value as valid.
ENVSYS_FVALID_AVG Marks the value_avg value as valid.
ENVSYS_FMONCRITICAL Enables and registers a new event to monitor a
critical state.
ENVSYS_FMONLIMITS Enables and registers a new event to monitor a
sensor's value crossing limits or thresholds.
ENVSYS_FMONSTCHANGED Enables and registers a new event to monitor
battery capacity or drive state sensors. The
flag is not effective if the units member is
not ENVSYS_DRIVE or ENVSYS_BATTERY_CAPACITY.
ENVSYS_FMONNOTSUPP Disallows setting of limits (or thresholds)
via the ENVSYS_SETDICTIONARY ioctl(2). This
flag only disables setting the limits from
userland. It has no effect on monitoring
flags set by the driver.
ENVSYS_FHAS_ENTROPY Allows this sensor to provide entropy for
rnd(4).
If the driver has to use any of the value_max, value_min, or
value_avg members, they should be marked as valid with the
appropriate flag.
⊕ If units is set to ENVSYS_DRIVE, the value_cur member must be set to
one of the following predefined states:
ENVSYS_DRIVE_EMPTY Drive state is unknown.
ENVSYS_DRIVE_READY Drive is ready.
ENVSYS_DRIVE_POWERUP Drive is powering up.
ENVSYS_DRIVE_ONLINE Drive is online.
ENVSYS_DRIVE_OFFLINE Drive is offline.
ENVSYS_DRIVE_IDLE Drive is idle.
ENVSYS_DRIVE_ACTIVE Drive is active.
ENVSYS_DRIVE_BUILD Drive is building.
ENVSYS_DRIVE_REBUILD Drive is rebuilding.
ENVSYS_DRIVE_POWERDOWN Drive is powering down.
ENVSYS_DRIVE_FAIL Drive has failed.
ENVSYS_DRIVE_PFAIL Drive has been degraded.
ENVSYS_DRIVE_MIGRATING Drive is migrating.
ENVSYS_DRIVE_CHECK Drive is checking its state.
⊕ If units is set to ENVSYS_BATTERY_CAPACITY, the value_cur member must
be set to one of the following predefined capacity states:
ENVSYS_BATTERY_CAPACITY_NORMAL Battery charge is normal.
ENVSYS_BATTERY_CAPACITY_CRITICAL Battery charge is critical.
ENVSYS_BATTERY_CAPACITY_LOW Battery charge is low.
ENVSYS_BATTERY_CAPACITY_WARNING Battery charge is on or below the
warning capacity.
⊕ The envsys(4) framework expects to have the values converted to a
unit that can be converted to another one easily. That means the
user should convert the value returned by the driver to the
appropriate unit. For example voltage sensors to mV, temperature
sensors to uK, Watts to mW, Ampere to mA, etc.
The following types shouldn't need any conversion:
ENVSYS_BATTERY_CAPACITY, ENVSYS_BATTERY_CHARGE, ENVSYS_INDICATOR,
ENVSYS_INTEGER, and ENVSYS_DRIVE.
PLEASE NOTE THAT YOU MUST AVOID USING FLOATING POINT OPERATIONS IN
KERNEL WHEN CONVERTING THE DATA RETURNED BY THE DRIVER TO THE
APPROPRIATE UNIT, IT'S NOT ALLOWED.
HOW TO ENABLE AUTOMATIC MONITORING IN SENSORS
The following example illustrates how to enable automatic monitoring in a
virtual driver for a critical state in the first sensor (sc_sensor[0]):
int
mydriver_initialize_sensors(struct mysoftc *sc)
{
...
/* sensor is initialized with a valid state */
sc->sc_sensor[0].state = ENVSYS_SVALID;
/*
* the monitor member must be true to enable
* automatic monitoring.
*/
sc->sc_sensor[0].monitor = true;
/* and now we specify the type of the monitoring event */
sc->sc_sensor[0].flags |= ENVSYS_FMONCRITICAL;
...
}
int
mydriver_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
{
struct mysoftc *sc = sme->sme_cookie;
/* we get current data from the driver */
edata->value_cur = sc->sc_getdata();
/*
* if value is too high, mark the sensor in
* critical state.
*/
if (edata->value_cur > MYDRIVER_SENSOR0_HIWAT) {
edata->state = ENVSYS_SCRITICAL;
/* a critical event will be sent now automatically */
} else {
/*
* if value is within the limits, and we came from
* a critical state make sure to change sensor's state
* to valid.
*/
edata->state = ENVSYS_SVALID;
}
...
}
CODE REFERENCES
The envsys 2 framework is implemented within the files:
sys/dev/sysmon/sysmon_envsys.c
sys/dev/sysmon/sysmon_envsys_events.c
sys/dev/sysmon/sysmon_envsys_tables.c
sys/dev/sysmon/sysmon_envsys_util.c
SEE ALSO
envsys(4), envstat(8)
HISTORY
The first envsys framework first appeared in NetBSD 1.5. The envsys 2
framework first appeared in NetBSD 5.0.
AUTHORS
The (current) envsys 2 framework was implemented by Juan Romero Pardines.
Additional input on the design was provided by many NetBSD developers
around the world.
The first envsys framework was implemented by Jason R. Thorpe, Tim
Rightnour, and Bill Squier.
NetBSD 10.99 July 13, 2012 NetBSD 10.99