Work on PSP Linux has started at PSP Linux. Check it out, especially if you're a developer. It should be pretty easy to get it running, since the PSP uses a memory stick and can load applications on there, but for now nobody knows for sure.
Short bit of specs:
- two MIPS32R2 cores with no TLB
- 128bit Bus
- 1 - 333MHz @ 1.2V (currently capped at 222MHz (The 222MHZ cap is software based and lies in the executed files, it is not firmware based so is easily bypassed))
- Main Memory: 32MB, 4MB eDRAM
- Bus Bandwidth: 2.6GB/sec
- I-Cache, D-Cache
- FPU, VFPU (Vector Unit) @ 2.6GFlops
- 3D-CG Extended Instructions
The description should be taken with a grain of salt. For instance, even the CPU core is not clear - maybe it is MIPS 4KE, but maybe 24K... The Coprocessor seems to be totally custom.
Lack of MMU makes this machine pretty much worthless except as a toy - which is what it was devised for, after all.
There is none and there won't be any despite some people's foolish claims and attempts. The hardware lacks a TLB and as such is too primitive to run a real Linux kernel. µClinux would be a potential alternative but that would mean no binary compatibility with existing Linux/MIPS.