intrusionsensor: Add hwmon reading method

This commit adds a new reading method for intrusionsensor, which reads
the chassis intrusion status from hwmon.

Example:
    {
         "Class": "Aspeed2600_Hwmon",
         "Name": "Chassis_Intrusion_Status",
         "Type": "ChassisIntrusionSensor"
    }

intrusionsensor will search for the sysfs hwmon name string in the
compatibleHwmonNames map using the Class string (e.g intrusion0_alarm
for Aspeed2600_Hwmon class) and read the chassis intrusion status from
it. This currently just supports Aspeed2600_Hwmon class which is based
on the aspeed-chassis driver from Aspeed SDK. The driver reads the
Intrusion Status bit in the CHAI10 register from AST2600. This bit
needs to be cleared every read in order to get the current state (which
means to write 0 to the hwmon file). In the condition of being cleared
every read, it will show 0 in hwmon for the normal state, and 1 for the
intrusion state.

Tested:

$ busctl get-property xyz.openbmc_project.IntrusionSensor \
 /xyz/openbmc_project/Chassis/Intrusion \
 xyz.openbmc_project.Chassis.Intrusion Status

If the chassis cover is closed: "Normal"
If the chassis cover is open: "HardwareIntrusion"

Signed-off-by: Chau Ly <chaul@amperecomputing.com>
Change-Id: I6f6a42592c8acae7be4f10e65a8b52ee30a4bd4f
3 files changed
tree: b04c392c99c3fb4989820423e938e93e7791c558
  1. include/
  2. service_files/
  3. src/
  4. subprojects/
  5. tests/
  6. .clang-format
  7. .clang-tidy
  8. .gitignore
  9. LICENSE
  10. meson.build
  11. meson_options.txt
  12. OWNERS
  13. README.md
README.md

dbus-sensors

dbus-sensors is a collection of sensor applications that provide the xyz.openbmc_project.Sensor collection of interfaces. They read sensor values from hwmon, d-bus, or direct driver access to provide readings. Some advance non-sensor features such as fan presence, pwm control, and automatic cpu detection (x86) are also supported.

key features

  • runtime re-configurable from d-bus (entity-manager or the like)

  • isolated: each sensor type is isolated into its own daemon, so a bug in one sensor is unlikely to affect another, and single sensor modifications are possible

  • async single-threaded: uses sdbusplus/asio bindings

  • multiple data inputs: hwmon, d-bus, direct driver access

dbus interfaces

A typical dbus-sensors object support the following dbus interfaces:

Path        /xyz/openbmc_project/sensors/<type>/<sensor_name>

Interfaces  xyz.openbmc_project.Sensor.Value
            xyz.openbmc_project.Sensor.Threshold.Critical
            xyz.openbmc_project.Sensor.Threshold.Warning
            xyz.openbmc_project.State.Decorator.Availability
            xyz.openbmc_project.State.Decorator.OperationalStatus
            xyz.openbmc_project.Association.Definitions

Sensor interfaces collection are described here.

Consumer examples of these interfaces are Redfish, Phosphor-Pid-Control, IPMI SDR.

Reactor

dbus-sensor daemons are reactors that dynamically create and update sensors configuration when system configuration gets updated.

Using asio timers and async calls, dbus-sensor daemons read sensor values and check thresholds periodically. PropertiesChanged signals will be broadcasted for other services to consume when value or threshold status change. OperationStatus is set to false if the sensor is determined to be faulty.

A simple sensor example can be found here.

configuration

Sensor devices are described using Exposes records in configuration file. Name and Type fields are required. Different sensor types have different fields. Refer to entity manager schema for complete list.

sensor documentation