florid_usb_protocol

This repository holds the shared USB protocol definitions used by Usb2Arm.

Current scope:

• bootloader control protocol on top of the vendored RPL framing
• packet definitions grouped under message/
• stream-session aliases grouped under session/
• byte-stream callback adapters grouped under transport/

Main header:

#include <florid_usb_protocol/protocol.hpp>

Current layout:

• florid_usb_protocol/message/upgrade.hpp
  • shared upgrade-control packet structs
• florid_usb_protocol/session/stream_session.hpp
  • generic stream-session alias over the vendored RPL request/ack machinery
• florid_usb_protocol/session/upgrade_control_session.hpp
  • the current upgrade-control message set bound onto a stream session
• florid_usb_protocol/transport/byte_stream_transport.hpp
  • small callback-based byte-stream adapters for USB CDC, TCP, or similar links

Upgrade control notes:

• request packets use RPL request/ack semantics
• data-bearing responses are separate packets carrying the original req_id
• this tree now only carries boot status, upgrade-mode switch, and reboot control packets; image upload is handled elsewhere

Zephyr module support:

• zephyr/module.yml exposes this repository as a standard Zephyr module
• zephyr/Kconfig gates the library behind CONFIG_FLORID_USB_PROTOCOL
• root CMakeLists.txt detects ZEPHYR_BASE and dispatches to cmake/Zephyr.cmake; otherwise it behaves like a normal standalone CMake subproject

Recommended Zephyr integration boundary:

• this library owns packet definitions, stream-session aliases, and byte-stream transport adapters
• the Zephyr app owns USB CDC I/O, protocol mode switching, upgrade policy, UpgradeManager, slot writes, and reboot policy
• a thin adapter layer should decode protocol requests and forward only the product-level actions upward, typically:
  • fill/respond boot status
  • request enter-upgrade mode
  • request reboot
  • pump transport RX/TX bytes between CDC and the protocol transport