Skip to main content

Bootloader for DE-2 board with OpenRISC

The last days have been filled with a lot of Verilog and ModelSim, so I thought it would be nice with some softer programing for a change.

After spending more time than I care to admit on hunting down the architecture reference guide (it is here if you need it) I figured I could as well write the bootloader that my OpenRISC platform will require. Since I haven't written anything about what I have in mind, here is a quick overview what I'm looking at creating:

  • Implement OpenRISC
  • Make the platform fit the DE-2 board from Terasic
  • It must be able to boot Linux
  • It would be awesome if I can get the DM9000 network controller working

That is the very formal (hmm) requirement specification I have in mind.

Anyhow, to boot Linux on the DE-2 platform I would need to have a big RAM (hence the SDRAM controller) of a couple megabytes at least. I would also need to have some permanent storage to boot from; the flash memory will be good for that I think.

When booting Linux the kernel expect that it resides in RAM space and will begin writing to memory. This is not so good when booting from flash. Therefore I need to transfer the kernel from flash to SDRAM and then execute the kernel from there. The bootloader would possibly need to update interrupt tables and such.

I present the version 0.1 bootloader. It prints a nice message, copies an image from directly after the bootloader to 0x0 and then jumps there. No interrupt handling for now.


Popular posts from this blog

Buying an IBM Mainframe

I bought an IBM mainframe for personal use. I am doing this for learning and figuring out how it works. If you are curious about what goes into this process, I hope this post will interest you. I am not the first one by far to do something like this. There are some people on the internet that I know have their own personal mainframes, and I have drawn inspiration from each and every one of them. You should follow them if you are interested in these things: @connorkrukosky @sebastian_wind @faultywarrior @kevinbowling1 This post is about buying an IBM z114 mainframe (picture 1) but should translate well to any of the IBM mainframes from z9 to z14. Picture 1: An IBM z114 mainframe in all its glory Source: IBM What to expect of the process Buying a mainframe takes time. I never spent so much time on a purchase before. In fact - I purchased my first apartment with probably less planning and research. Compared to buying an apartment you have no guard rails. You are left

Brocade Fabric OS downloads

Fabric OS is what runs on the SAN switches I will be using for the mainframe. It has a bit of annoying upgrade path as the guldmyr blog can attest to. TL;DR is that you need to do minor upgrades (6.3 -> 6.4 -> 7.0 -> ... > 7.4) which requires you to get all  Fabric OS images for those versions. Not always easy. So, let's make it a bit easier. Hopefully this will not end up with the links being taken down, but at least it helped somebody I hope. These downloads worked for me and are hash-verified when I could find a hash to verify against. Use at your own risk etc. The URLs are: ftp://ftp.hp.c

Updating a Mainframe

I have done systems administration for as long as I remember, and while I have set up countless of services and servers - I have quite limited experience working with the full life-cycle of truly enterprise software. Therefor, I thought it would be interesting to understand more on how one would plan for and execute updates on an IBM Z Series mainframe.