232 lines
10 KiB
Markdown
232 lines
10 KiB
Markdown
|
# Multi-host Postcode Support
|
||
|
|
|
||
|
|
Author: Manikandan Elumalai, [manikandan.hcl.ers.epl@gmail.com]
|
||
|
|
|
||
|
|
Other contributors: None
|
||
|
|
|
||
|
|
Created: 2020-07-02
|
||
|
|
|
||
|
|
## Problem Description
|
||
|
|
|
||
|
|
The current implementation in the phosphor-host-postd supports only single host
|
||
|
|
postcode access through LPC interface.
|
||
|
|
|
||
|
|
As the open BMC architecture is evolving, the single host support becomes
|
||
|
|
contingent and needs multiple-host post code access to be implemented.
|
||
|
|
|
||
|
|
## Background and References
|
||
|
|
|
||
|
|
The below component diagram shows the design for single-host postcode and
|
||
|
|
history at high-level overview. The single-host design is updated slightly from
|
||
|
|
the original to better comply with community conventions (using suffix 0 on
|
||
|
|
D-Bus objects).
|
||
|
|
|
||
|
|
Diagram Legend: |Label|Signifies| |-----|---------| |`I:` |D-Bus interface|
|
||
|
|
|`S:` |D-Bus service name (well-known bus name)| |`R:` |Repository name| |`U:`
|
||
|
|
|Systemd service unit name| |`A:` |Executable name| |`H:` |HW Module|
|
||
|
|
|
||
|
|
```
|
||
|
|
+-----------+
|
||
|
|
+------+ | 7 segment |
|
||
|
|
| Host | | display |
|
||
|
|
+--+---+ +-----^-----+
|
||
|
|
| |
|
||
|
|
+-------------------------+--------------------+--------+
|
||
|
|
| BMC | | |
|
||
|
|
| +--v----+ +-----+-----+ |
|
||
|
|
| | H:LPC +---------> H:(S)GPIO | |
|
||
|
|
| +--+----+ +-----------+ |
|
||
|
|
| | |
|
||
|
|
| +-----------------------v--------------+ |
|
||
|
|
| | U:lpcsnoop | |
|
||
|
|
| | | |
|
||
|
|
| | Current POST code: | |
|
||
|
|
| | S:xyz.openbmc_project.State.Boot.Raw | |
|
||
|
|
| | /xyz/openbmc_project/state/boot/raw0 | |
|
||
|
|
| | I:xyz.openbmc_project.State.Boot.Raw >----+ |
|
||
|
|
| +--------------------------------------+ | |
|
||
|
|
| | |
|
||
|
|
| +-------------------------------------------v---+ |
|
||
|
|
| | U:xyz.openbmc_project.State.Boot.PostCode | |
|
||
|
|
| | POST code history: | |
|
||
|
|
| | +-------------------------------------------+ | |
|
||
|
|
| | | S:xyz.openbmc_project.State.Boot.PostCode0| | |
|
||
|
|
| | | /xyz/openbmc_project/State/Boot/PostCode0 | | |
|
||
|
|
| | | I:xyz.openbmc_project.State.Boot.PostCode >----+ |
|
||
|
|
| | +-------------------------------------------+ | | |
|
||
|
|
| +-----------------------------------------------+ | |
|
||
|
|
| | |
|
||
|
|
| +--------------------------------+ | |
|
||
|
|
| | Other consumers of POST codes: <------------+ |
|
||
|
|
| | Redfish, etc... | |
|
||
|
|
| +--------------------------------+ |
|
||
|
|
+-------------------------------------------------------+
|
||
|
|
```
|
||
|
|
|
||
|
|
Since multiple hosts cannot coherently write their POST codes to the same place,
|
||
|
|
an additional datapath is needed to receive POST codes from each host. Since
|
||
|
|
this new datapath would not have built-in support in ASPEED hardware, additional
|
||
|
|
logic is also needed drive the 7-segment display.
|
||
|
|
|
||
|
|
## Requirements
|
||
|
|
|
||
|
|
- Read postcode from all servers.
|
||
|
|
- Display the host postcode to the 7 segment display based on host position
|
||
|
|
selection.
|
||
|
|
- Provide a command interface for user to see any server(multi-host) current
|
||
|
|
postcode.
|
||
|
|
- Provide a command interface for user to see any server(multi-host) postcode
|
||
|
|
history.
|
||
|
|
- Support for hot-plug-able host.
|
||
|
|
|
||
|
|
## Proposed Design
|
||
|
|
|
||
|
|
This document proposes a new design engaging the IPMB interface to read the
|
||
|
|
port-80 post code from multiple-host. The existing single host LPC snooping
|
||
|
|
mechanism remains unaffected, and is not shown in diagrams below. This design
|
||
|
|
also supports host discovery including the hot-plug-able host connected in the
|
||
|
|
slot.
|
||
|
|
|
||
|
|
Following modules will be updated for this implementation
|
||
|
|
|
||
|
|
- phosphor-host-postd.
|
||
|
|
- phosphor-post-code-manager.
|
||
|
|
- platform specific OEM handler (fb-ipmi-oem).
|
||
|
|
- bmcweb (redfish logging service).
|
||
|
|
|
||
|
|
**Interface Diagram**
|
||
|
|
|
||
|
|
Provided below the post code interface diagram with flow sequence
|
||
|
|
|
||
|
|
```
|
||
|
|
+---------------------------------------------------+
|
||
|
|
| BMC |
|
||
|
|
| |
|
||
|
|
| +-----------------------+ +----------------+ | +----+-------------+
|
||
|
|
| | A:ipmid | | IPMB Bridge <--+--IPMB-+-|BIC | |
|
||
|
|
| | | | (R:ipmbbridge) | | | | | Host1 |
|
||
|
|
| | +-------------------+ | +--------+-------+ | | +------------------+
|
||
|
|
| | | OEM IPMI Handlers | | | | | .
|
||
|
|
| | | (R:fb-ipmi-oem) <-+-------------+ | | .
|
||
|
|
| | --------------------+ | +----------------+ | | .
|
||
|
|
| +-+---------------------+ | Host selection | | | +------------------+
|
||
|
|
| | | monitoring <---+--+ +-|BIC | |
|
||
|
|
| | +---------+------+ | | | | HostN |
|
||
|
|
| | | | | +------------------+
|
||
|
|
| | +---------------------------------v------+ | |
|
||
|
|
| | | R:phosphor-host-postd (1 process) | | | +---------------+
|
||
|
|
| | | Per-host POST code object: | | +-GPIO-| Button/switch |
|
||
|
|
| | | /xyz/openbmc_project/state/boot/raw<N> | | | input device |
|
||
|
|
| +-> I:xyz.openbmc_project.State.Boot.Raw >-+ | +---------------+
|
||
|
|
| +---------------------------------+------+ | |
|
||
|
|
| | | | +-------------------+
|
||
|
|
| +--------+-+----GPIO-> 7-segment display |
|
||
|
|
| | | +-------------------+
|
||
|
|
| | +------+
|
||
|
|
| | |
|
||
|
|
| +----------------------------------------------v---+ |
|
||
|
|
| | R:phosphor-post-code-manager (N processes) | |
|
||
|
|
| | Per-host POST code history service: | |
|
||
|
|
| | +----------------------------------------------+ | |
|
||
|
|
| | | S:xyz.openbmc_project.State.Boot.PostCode<N> | | |
|
||
|
|
| | | /xyz/openbmc_project/State/Boot/PostCode<N> | | |
|
||
|
|
| | | I:xyz.openbmc_project.State.Boot.PostCode >-+-+ |
|
||
|
|
| | +----------------------------------------------+ | | |
|
||
|
|
| | ... | | |
|
||
|
|
| +--------------------------------------------------+ | |
|
||
|
|
| | |
|
||
|
|
| +--------------------------------+ | |
|
||
|
|
| | Other consumers of POST codes: <--------------+ |
|
||
|
|
| | Redfish, CLI, etc... | |
|
||
|
|
| +--------------------------------+ |
|
||
|
|
| |
|
||
|
|
+----------------------------------------------------------+
|
||
|
|
```
|
||
|
|
|
||
|
|
**Postcode Flow:**
|
||
|
|
|
||
|
|
- BMC power-on the host.
|
||
|
|
- Host starts sending the postcode IPMI message continuously to the BMC.
|
||
|
|
- The ipmbbridged (phosphor-ipmi-ipmb) passes along the message to IPMI daemon.
|
||
|
|
- The ipmid (phosphor-ipmi-host) appends host information with postcode and
|
||
|
|
writes value to appropriate D-Bus object hosted by phosphor-host-postd.
|
||
|
|
- phosphor-host-postd displays postcode in the seven segment display based on
|
||
|
|
host position reads through D-bus interface.
|
||
|
|
- phosphor-post-code-manager receives new POST codes via D-Bus signal and stores
|
||
|
|
the postcode as history in the /var directory.
|
||
|
|
|
||
|
|
## Platform Specific OEM Handler (fb-ipmi-oem)
|
||
|
|
|
||
|
|
This library is part of the
|
||
|
|
[phosphor-ipmi-host](https://github.com/openbmc/phosphor-host-ipmid) and gets
|
||
|
|
the postcode from host through
|
||
|
|
[phosphor-ipmi-ipmb](https://github.com/openbmc/ipmbbridge).
|
||
|
|
|
||
|
|
- Register IPMI OEM postcode callback handler.
|
||
|
|
- Extract postcode from IPMI message (phosphor-ipmi-host/phosphor-ipmi-ipmb).
|
||
|
|
- Sets `Value` property on appropriate D-Bus `Raw` object hosted by
|
||
|
|
`phosphor-host-postd`. Other programs (e.g. `phosphor-post-code-manager`) can
|
||
|
|
subscribe to `PropertiesChanged` signals on this object to get the updates.
|
||
|
|
|
||
|
|
## phosphor-host-postd
|
||
|
|
|
||
|
|
This implementation involves the following changes in the phosphor-host-postd.
|
||
|
|
|
||
|
|
- `phosphor-host-postd` handles property set events for the `Value` property on
|
||
|
|
each instance of the `xyz.openbmc_project.State.Boot.Raw` interface.
|
||
|
|
- phosphor-host-postd reads the host selection from the dbus property.
|
||
|
|
- Display the latest postcode of the selected host read through D-Bus on a
|
||
|
|
7-segment display.
|
||
|
|
|
||
|
|
**D-Bus interface**
|
||
|
|
|
||
|
|
The following D-Bus names need to be created for the multi-host post-code.
|
||
|
|
|
||
|
|
Service name -- xyz.openbmc_project.State.Boot.Raw
|
||
|
|
|
||
|
|
Obj path name -- /xyz/openbmc_project/State/Boot/RawX(1,2..N)
|
||
|
|
|
||
|
|
Interface name -- xyz.openbmc_project.State.Boot.Raw
|
||
|
|
|
||
|
|
## phosphor-post-code-manager
|
||
|
|
|
||
|
|
The phosphor-post-code-manager is a multi service design for multi-host. The
|
||
|
|
single host postcode handling D-bus naming conventions will be updated to comply
|
||
|
|
with the community naming scheme.
|
||
|
|
|
||
|
|
- Create D-Bus service names for single-host and multi-host system accordingly.
|
||
|
|
The community follows conventions Host0 for single host and Host1 to N for
|
||
|
|
multi-host.
|
||
|
|
- phosphor-post-code-manager subscribes to changes on the `Raw<N>` object hosted
|
||
|
|
by `phosphor-host-postd`.
|
||
|
|
- Store/retrieve post-code from directory (/var/lib/phosphor-post-code-manager/
|
||
|
|
hostX(1,2,3..N)) based on event received from phosphor-host-postd.
|
||
|
|
|
||
|
|
**D-Bus interface**
|
||
|
|
|
||
|
|
The following D-Bus names needs to be created for multi-host post-code.
|
||
|
|
|
||
|
|
Service name -- xyz.openbmc_project.State.Boot.PostCodeX(1,2..N)
|
||
|
|
|
||
|
|
Obj path name -- /xyz/openbmc_project/State/Boot/PostCodeX(1,2..N)
|
||
|
|
|
||
|
|
Interface name -- xyz.openbmc_project.State.Boot.PostCode
|
||
|
|
|
||
|
|
## bmcweb
|
||
|
|
|
||
|
|
The postcode history needs to be handled for the multi-host through redfish
|
||
|
|
logging service.
|
||
|
|
|
||
|
|
## Alternate design
|
||
|
|
|
||
|
|
**phosphor-post-code-manager single process approach**
|
||
|
|
|
||
|
|
This implementation consider single service to handle multi-host postcode. In
|
||
|
|
this approach, all D-Bus handling will taken care by the single process.
|
||
|
|
|
||
|
|
Single service is different than existing x86-power-control and obmc-console
|
||
|
|
where multi-service approach is used.
|
||
|
|
|
||
|
|
Multi-service approach is more scalable to handle multi-host than the single
|
||
|
|
service.
|