P4 fixes

resources/espressif__esp_hosted/common/proto/README.md

@@ -0,0 +1,53 @@
+# About Proto Files
+
+
+## Protobuf Submodule
+
+[protobuf-c](https://github.com/protobuf-c/protobuf-c) is open source code used as submodule in ESP-Hosted-FG in directory `../protobuf-c/`
+If this directory is empty, please run
+```sh
+$ cd esp-hosted
+$ git submodule update --init --recursive
+```
+
+## Files
+
+- `esp_hosted_rpc.proto`
+  - This is Ready-To-Use protobuf file which has messages for Request / Response / Events to communicate between Host and ESP
+  - User can add his own message field in `.proto` file and generate respective C files using 'protoc'
+
+- `esp_hosted_rpc.pb-c.c` & `esp_hosted_rpc.pb-c.h`
+  - Ready-To-Use Source Generated files using `esp_hosted_rpc.proto`
+  - These files also cached which was generated with current `esp_hosted_rpc.proto` file for easy use (No need to generate again)
+  - If any addition or modifications `esp_hosted_rpc.proto` done, these files need to be re-generated
+
+
+## Generate esp_hosted_rpc.pb-c.c & esp_hosted_rpc.pb-c.h
+
+If you want to add or modify existing set of RPC procedures supported, you need to modify `esp_hosted_rpc.proto` as needed and build it to generate new set of `esp_hosted_rpc.pb-c.c` & `esp_hosted_rpc.pb-c.h`.
+For this, third party software for protobuf C compiler is needed to be installed
+- Debian/Ubuntu
+  - sudo apt install protobuf-c-compiler
+- Mac OS
+  - brew install protobuf
+- Windows
+  - check https://github.com/protobuf-c/protobuf-c
+
+`protoc-c` command should be available once installed.
+
+This software might only be needed on development environment, Once esp_hosted_rpc.pb-c.c & esp_hosted_rpc.pb-c.h files are generated, could also be uninstalled.
+
+##### Steps to generate
+```sh
+$ cd <path/to/esp_hosted_fg>/common/proto
+$ protoc-c esp_hosted_rpc.proto --c_out=.
+```
+
+## Add new RPC message
+To send an new RPC request/response
+<TBD>
+1. Add C function in `host/host_common/commands.c`
+2. Create python binding in `host/linux/host_control/python_support/commands_map_py_to_c.py` and its python function in `host/linux/host_control/python_support/commands_lib.py`.
+3. Add ESP side C function in `esp/esp_driver/network_adapter/main/slave_commands.c`, respective to python function, to handle added message field.
+
+User can test added functionality using `host/linux/host_control/python_support/test.py`.