[U-Boot-Users] Which board is similar to mine, and how do I build a custom config?

[Peter Asemann]

Hi there!

I need to make a u-boot config for my custom MPC875-based board.

Until now I just copied everything from esteem192e as it seemed most
similar to my hardware to me, and renamed everything to "esm" which is
the "codename" of the hardware.

Anyway, I'm not sure if there isn't a board that is more similar to mine
which I missed, that's why I'm asking you.

The board will have an MPC875 at 133MHz speed (the first problem, as the 
u-boot readme doesn't mention a CPU type CONFIG_MPC875, and there also 
is no CPU of the 870/875/880/885 family available).
It'll have an ethernet LXT970A PHY chip and an ISP1301 USB PHY chip for
net/usb, plus a three-pin serial interface connected directly to the CPU.

The RAM will consist of 2x K4S561632E SDRAM chips (2*32MB). The 2 chips
each take 16bits from the 32bit address bus, chip1 0-15, chip2 16-31.
For addressing the adress lines A17-A29 connect to both chips' inputs
A0-A12, address lines A6 and A7 connect to the chips' inputs BA0 and BA1.

The flash will consist of 4x AM29LV160D chips, each getting 8 bits of
the 32bit data bus, all being connected to the 21bit wide adress bus.
Address bus lines A1 to A20 connect to the chips' inputs A0-A19, the
chips' inputs called D15/A1 are connected to address bus line A0.

There will be more hardware available on the board, but I won't bother
with that as it's not important for the task of getting that PowerPC
subsystem running, I suppose.

I could send you schematic diagrams of the layout as graphics if these
explanations are not explanatory enough.

The README says of u-boot says for a custom config I'll need a
u-boot.lds, a flash.c, a board.c and some more things. Do I need to
change anything about the u-boot.lds, the flash.c or the board.c - I
hope a custom .../include/configs/ESM.h will suffice?

Thanks in advance,

Peter Asemann