U Boot Porting Guide - lalilulelulz/Chromium-OS-Coreboot GitHub Wiki

This guide describes how to port U-Boot to a new Chrome OS platform. Although it specifically describes using U-Boot with Chrome OS, the general process, information, and examples apply to using U-Boot with any Chromium OS. The guide provides a conceptual framework for U-Boot porting tasks as well as task-oriented guidance for the porting process.

Overview of the Porting Process

High-level view of the porting process Development flow 2. Concepts Boot process Verified boot Development flow Firmware image Firmware development USB firmware download Device Firmware Update (DFU) - over the air Bundled firmware Secondary program loader (SPL) Flat device tree Keys and signing Environment 3. Drivers for Chrome OS Audio codec Clock Ethernet GPIO (General Purpose Input/Output) I2C (Inter-IC Communications) I2S (Inter-IC Sound) Keyboard LCD (Liquid Crystal Display) NAND (alternative to SDMMC if supported) Pinmux (Pin Multiplexing) Power PWM (Pulse Width Modulation) SDMMC (Secure Digital Multimedia Memory Card) and eMMC SPI SPI Flash (Serial Peripheral Interface Flash) Timer TMU (Thermal Management Unit) TPM (Trusted Platform Module) UART (Universal Asynchronous Receiver Transmitter) USB host

DSTREAM/ DS-5 - debug tools ICE/Trace - debug tools Appendix A. Using nv-U-Boot on the Samsung Chromebook