GSoC 2015 H8S EC firmware

Hi community,

I’m Alexander Couzens on the list and in IRC known as lynxis. I’ve experience with embedded Linux and hardware integration of wireless devices using OpenWrt. I started modifying my vendor BIOS several years ago because my brand new Lenovo X201t didn’t allow me to use good wireless cards because it checked all pci networks devices against a white list. After my mainboard was replaced I had to do the same modification again or install coreboot. Of course I went for coreboot 🙂 While installing coreboot I also started developing it, my GSoC is the H8S Embedded Controller firmware. The EC controls a lot of things in your laptop. An EC controls the battery charging and discharging, the keyboards, docking and undocking, multiple sensors, thermals sensors, fan, lid switch and power regulators.

So the EC is a very important chip. To have open source firmware for this chip is also improving the coreboot support. The H8S is an old chip from Hitachi which is built into a lot of Thinkpads, beginning from early models (maybe even before x40) to modern models like the x220.

My first milestone is the ability to flash a H8S without turning the Laptop on. I’ve already started soldering additional wires to an old T40 a friend gave me, with the additional wires it should be possible to flash the H8S over a serial protocol supported by the ROM loader. After a successful flash I need to set up a proper toolchain I will start with small test application like blinking a led. In the End I’ll do a port of ChromeEC for the H8S.