On Wed, Aug 11, 2010 at 12:15 PM, Votier, Sean (DS-1) SVotier@drs-ds.com wrote:
I’ve been on and off the list for a few months. My email system doesn’t seem to like list traffic so it’s a bit touch and go so I will have to see how long it lasts. It’s been interesting reading but now I have a question….
I’m writing some BIOS code for the I7520 chipset. In general, with these chipsets is there some basic legacy I/O mapping for parallel, serial and other real mode devices by default on power up? I’m hoping that something similar happens to the way that the Firmware Hub is made to look like a BIOS rom on power up. I need to read one GPIO pin very early in the bios initialisation and hope I can just look at a bit at I/O address 378.
I don't have any chipset-specific information, but here are a couple of thoughts: - Is there a Super IO chip? Generally the Super IO chip handles serial & has some GPIO pins. - To allow the Super IO to function correctly, the IO there is often subtractively decoded (if the chipset doesn't claim an address, it passes it on.) - I would think that there would be a register in the PCI space for the chipset that controls the address of the GPIO pins.
Myles