Using DTB overlays in OP-TEE
summary
Upstream OP-TEE adds an in-memory device tree overlay mechanism so a board port supplies an overlay that U-Boot merges into the kernel DTB at boot, avoiding hardcoding and allowing independent FIP/FIT updates. Implementation is small — roughly 5–10 lines of code plus a build flag config_external_dtb_overlay — and uses U-Boot to extract the FIT DTB and run fdt apply; it needs only to publish the memory reserve address. It runs on Warp 7 and at least one other board and is being ported to two more.
AI-written summary · about
chapters (5)
- 0:00Start
- 0:35Introduction
- 1:28Arm Mbed Linux OS (MBL)
- 5:35MBL Boot Flow Arm32
- 6:23Solution is OP-TEE DTB Overlay • OP-TEE provides a DTB overlay at a known location
related talks
01h 10mBoF: Devicetree
50mRethinking U-Boot Devicetree Story
55mImplementing State-of-the-Art U-Boot Port, 2018 Edition
51mShipping Multiple Devicetrees: How to Identify Which DTB Is for My Board?
29mChallenges in Device Tree Sync - kernel, Zephyr, U-boot, System DT
26mBridging Worlds: Using Device Tree Overlays To Support Complex PCI Devices in Linux
40mSecond Source Component Probing on Device Tree Platforms
11mOP-TEE open-source security for the mass-market