I think it might be a good idea to have some porting plan with all those milestones etc. to get better motivation and feeling about work being done. Fortunately David Terei (GHC developer who implemented GHC LLVM backend) suggested such plan to me in a private email conversation and even agreed to allow putting it somewhere on web. I’ve entered this on GHC/LLVM Trac Wiki here. Please keep in mind this is really high-level plan what to do. For “how to do” you should consult at least linked design & documentation page and other related GHC and LLVM documents.
And if you are curious about where I’m with my GHC/LLVM/ARM port then I’m at (3) point now.