[coreboot] Quick question on vt8237 smbus

Corey Osgood corey.osgood at gmail.com
Mon Oct 13 20:36:14 CEST 2008

I'm working on vt8237 smbus in v3, and I had a quick question, mostly for
Rudolf Marek and Bari, but feel free to jump in with your 2 cents:

u8 smbus_read_byte(u16 dimm, u8 offset, u16 smbus_io_base)
    u8 val;

    printk(BIOS_SPEW, "SMBus Read from DIMM %1x at address 0x%4x\n",
                dimm, offset);


    /* Clear host data port. */
    outb(0x00, smbus_io_base + SMBHSTDAT0);

    dimm = (dimm << 1) | 1;

    outb(dimm, smbus_io_base + SMBXMITADD);

The dimm = (dimm << 1) | 1 is something that came from a via southbridge
porting guide (NOT the one for the vt8237r, I don't have that one). With it,
my spd addresses are 0x50, 0x51, etc, without it, they'd be 0xa1, 0xa3, etc.
Which would be preferred? Do you think we'd ever need a 0xa0 or 0xa2

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.coreboot.org/pipermail/coreboot/attachments/20081013/08654fdf/attachment.html>

More information about the coreboot mailing list