sysmon_envsys(9)
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SYSMON_ENVSYS(9) NetBSD 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 *);
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 sys-
mon_envsys structure and takes care of initialization of some private
features.
Once we have the object we could start initializing sensors (see the
SENSOR DETAILS section for more information) and attaching them to the
device, this is acomplished by the sysmon_envsys_sensor_attach() func-
tion. This function attachs the envsys_data_t (sensor) specified as sec-
ond argument into the sysmon_envsys object specified in the first argu-
ment.
Finally when the sensors are already attached, the device needs to set
some required (and optional) members of the sysmon_envsys struct before
calling the sysmon_envsys_register() function to register the device.
If there's some error before registering the device, the
sysmon_envsys_destroy() function must be used to detach the sensors pre-
viously attached and free the sysmon_envsys object allocated by the
sysmon_envsys_create() function.
The sysmon_envsys structure is defined as follow (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 *);
};
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 sensors data and the
driver will use its own method. Hence
sme_cookie won't be necessary either
(OPTIONAL).
sme_events_timeout This is used to specify the default timeout
value that will be used to check for critical
events if any monitoring flag was set. The
value is used as seconds (OPTIONAL).
If the driver wants to refresh sensors data via the sysmon_envsys frame-
work, the following members must be specified:
sme_cookie Pointer to the device struct (also called
``softc'' ). This may be used in the
sme_refresh function callback.
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 of the returned data by
the driver. NOTE: You don't have to refresh
all sensors, only the sensor specified by the
edata->sensor index.
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 will be
detached; finally the sysmon_envsys object will be freed, so there's no
need to call sysmon_envsys_destroy() if we are going to unregister a
device.
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 cur-
rent state (on/off).
SME_CLASS_BATTERY
This class is for devices that want to act as an 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 won't
never send a low-power event to the powerd(8) daemon (if running)
when all battery devices are in a critical state. The critical
state means that 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) and
will shutdown the system gracefully via 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 don't have the
sensors required, the low-power event will never be sent, and the grace-
ful shutdown won't be possible.
SENSOR DETAILS
Each sensor uses a envsys_data_t structure, it's defined as follow (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;
bool monitor;
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.
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.
monitor Used to enable automatic sensor monitoring (by default
it's disabled). The automatic sensor monitoring will check
if a condition is met periodically and will send an event
to the powerd(8) daemon (if running). The monitoring event
will be registered when this flag is true and one or more
of the ENVSYS_FMONFOO flags were set in the flags member.
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.
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). Pos-
sible 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_FMONCRITUNDER Enables and registers a new event to monitor a
critical under state.
ENVSYS_FMONCRITOVER Enables and registers a new event to monitor a
critical over state.
ENVSYS_FMONWARNUNDER Enables and registers a new event to monitor a
warning under state.
ENVSYS_FMONWARNOVER Enables and registers a new event to monitor a
warning over state.
ENVSYS_FMONSTCHANGED Enables and registers a new event to monitor
Battery capacity or drive state sensors. It
won't be effective if the units member is not
set to ENVSYS_DRIVE or
ENVSYS_BATTERY_CAPACITY.
ENVSYS_FMONNOTSUPP Disallows to set a critical limit via the
ENVSYS_SETDICTIONARY ioctl(2). This flag has
not any effect for monitoring flags set in the
driver and it's only meant to disable setting
critical limits from userland.
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 appropiate flag.
· If units is set to ENVSYS_DRIVE, there are some predefined states
that must be set (only one) to the value_cur member:
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, there are some predefined
capacity states that must be set (only one) to the value_cur member:
ENVSYS_BATTERY_CAPACITY_NORMAL Battery charge is in normal capac-
ity.
ENVSYS_BATTERY_CAPACITY_CRITICAL Battery charge is in critical
capacity.
ENVSYS_BATTERY_CAPACITY_LOW Battery charge is in low capacity.
ENVSYS_BATTERY_CAPACITY_WARNING Battery charge is in warning capac-
ity.
· 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 appropiate
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
APPROPIATE 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
This section describes places within the NetBSD source tree where actual
code implementing the envsys 2 framework can be found. All pathnames are
relative to /usr/src.
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
There's an example LKM driver that shows how the framework works in:
sys/lkm/misc/envsys2/lkminit_envsys2.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 Right-
nour and Bill Squier.
NetBSD 5.0 February 28, 2008 NetBSD 5.0
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