The phosphor-power-sequencer application powers all the chassis in the system on and off. It also monitors the power good (pgood) state in each chassis.
Note: Many changes have been made to this documentation to define how multiple chassis support will work. This support is not yet implemented in this application. The support is also dependent on changes to the existing phosphor-chassis-state-manager application and the planned new phosphor-chassis-power application. This disclaimer will be removed when this support is fully implemented.
phosphor-power-sequencer is a single-threaded C++ executable. It is a daemon process that runs continually. It is launched by systemd when the BMC reaches the Ready state and before the system is powered on.
phosphor-power-sequencer is driven by an optional, system-specific JSON configuration file. The config file is found and parsed at runtime. The parsing process creates a collection of C++ objects. These objects represent the chassis, power sequencer devices, voltage rails, GPIOs, and fault checks to perform.
See Internal Design for more information.
A power sequencer device enables (turns on) the voltage rails in the correct order and monitors them for pgood faults.
phosphor-power-sequencer currently supports the following power sequencer device types:
Additional device types can be supported by creating a new sub-class within the PowerSequencerDevice class hierarchy. See Internal Design for more information.
If the power sequencer device type is not supported, phosphor-power-sequencer can still power the system on/off and detect chassis pgood faults. However, it will not be able to determine which voltage rail caused a pgood fault.
phosphor-power-sequencer uses the power sequencer device to power on all main (non-standby) voltage rails in each chassis.
See Powering On for more information.
phosphor-power-sequencer uses the power sequencer device to power off all main (non-standby) voltage rails in each chassis.
See Powering Off for more information.
phosphor-power-sequencer periodically reads the chassis pgood state from the power sequencer device. See Monitoring Chassis Power Good for more information.
If the chassis pgood state is false when it should be true, a chassis pgood fault has occurred. phosphor-power-sequencer uses information from the power sequencer device to determine the cause.
See Power Good Faults for more information.
phosphor-power-sequencer is configured by an optional JSON configuration file. The configuration file defines the voltage rails in the system and how they should be monitored.
JSON configuration files are system-specific and are stored in the config_files sub-directory.
Documentation is available on the configuration file format.
If no configuration file is found for the current system, phosphor-power-sequencer can still power the system on/off and detect chassis pgood faults. However, it will not be able to determine which voltage rail caused a pgood fault.
Automated test cases exist for most of the code in this application. See Testing for more information.
The phosphor-chassis-state-manager application exists in the phosphor-state-manager repository. It supports user requests to power on and off the system hardware. It publishes the xyz.openbmc_project.State.Chassis D-Bus interface.
The phosphor-chassis-power application exists in the phosphor-power repository. It monitors the chassis input power state using GPIOs.
The phosphor-power-supply application exists in the phosphor-power repository. It monitors the power supply devices within each chassis.