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 *);

     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 detachs 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 per-
     formed 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 sen-
     sors.

     Drivers can also call the sysmon_envsys_update_limits() function when it
     is necessary to reinitialize a sensor's threshhold 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 mem-
     bers 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.  Cur-
                         rently 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 frame-
     work, 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 depend-
                         ing 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 user-
                         land 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 con-
                         trol over setting the sensor's state based on hard-
                         ware 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 orig-
                         inal, boot-time values.

                         If the sme_set_limits member is not specified, the
                         device driver is not informed of changes to the sen-
                         sor'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 cur-
            rent 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.
         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_* val-
                                  ues 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.

         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 appropri-
         ate 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 Right-
     nour, and Bill Squier.

NetBSD 6.0.1                    April 10, 2010                    NetBSD 6.0.1

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