post-code-manager: Add documentation
This commit would attempt to add few basic details on how
to build post-code-manager & the dbus service that it exposes.
Signed-off-by: Manojkiran Eda <manojkiran.eda@gmail.com>
Change-Id: I6b9b350e6009f008fb5c186320884f527b97624a
diff --git a/README.md b/README.md
index 074a0d1..b0c75d9 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,25 @@
-# phosphor-post-code-manager
\ No newline at end of file
+# phosphor-post-code-manager
+
+This phosphor-post-code-manager repository provides an infrastructure to persist the POST codes in BMC filesystem & it also owns
+the systemd services that are responsible for exposing the BIOS Post Codes to rest of the world via redfish.
+
+## To Build
+
+To build phosphor-post-code-manager package , do the following steps:
+
+``` bash
+meson <build directory>
+ninja -C <build directory>
+```
+
+## Hosted Services
+
+This repository ships `xyz.openbmc_project.State.Boot.PostCode.service` systemd service along with its [template version](https://github.com/openbmc/docs/blob/master/designs/multi-host-postcode.md) and a tiny binary that exposes the necessary [dbus interfaces & methods](https://github.com/openbmc/phosphor-dbus-interfaces/blob/master/yaml/xyz/openbmc_project/State/Boot/PostCode.interface.yaml) to extract the POST codes per boot cycle.
+
+## Architecture
+
+This repository is tightly coupled with [phosphor-host-postd](https://github.com/openbmc/phosphor-host-postd) OpenBMC respository which is responsible for emitting the dbus signals for every new POST Code.
+
+phosphor-post-code-manager is architected to look for the property changed signals which are being emitted from the service that hosts [Value](https://github.com/openbmc/phosphor-dbus-interfaces/blob/master/yaml/xyz/openbmc_project/State/Boot/Raw.interface.yaml) property on `xyz.openbmc_project.State.Boot.Raw` interface & archive them per boot on the filesystem, so that those can be exposed over [redfish](https://github.com/openbmc/docs/blob/master/designs/redfish-postcodes.md)
+
+