I'm basically using this code in auto.c (based on bitworks/ims stuff):
sdram_initialize(sizeof(cpu)/sizeof(cpu[0]), cpu); enable_mainboard_devices(); ram_check(0x10000000, 0x2000000);
Is that the canonical way to test whether RAM init works?
The "canonical" way is to attach a memory bus analyser to your board. Failing that, you can run some stress tests (like, boot Linux and do some disk+network load on it, or similar). If everything works, your memory works, eh? :-)
What's the absolute minimum config I need to get _something_ to boot, so that I can verify that RAM init works?
You can dump out the PCI config space of the memory controller after its init -- so you can check if that looks good (against the data sheet). After that, try a "Hello, World!" payload. Take little steps at a time :-)
Segher