On Tue, Oct 27, 2009 at 2:04 PM, Gregg Levine <[email protected]>wrote:
> On Tue, Oct 27, 2009 at 4:51 PM, David Hendricks <[email protected]> > wrote: > > On Tue, Oct 27, 2009 at 6:06 AM, Darmawan Salihun > > <[email protected]> wrote: > >> > >> What is the BIOS RAM in AMD SB7XX used for? > > > > Looks like scratchpad memory to me. From the public doc: > > > > 3.3 BIOS RAM > > The SB700 has 256 bytes of BIOS RAM. Data in this RAM is preserved until > > RSMRST# or S5 is > > asserted, or until power is lost. > > This RAM is accessed using index and data registers at CD4h/CD5h. > > > > Might it be enough to act as a very, very small cache-as-RAM substitute > > until CAR can be set up? > > > > On Tue, Oct 27, 2009 at 6:06 AM, Darmawan Salihun > > <[email protected]> wrote: > >> > >> Is it to buffer the BIOS contents from SPI flash chip prior to > >> execution of the very first instruction? > >> I recall that it's impossible to execute code directly in an SPI chip. > > > > That's correct, afaik. > > -- > > David Hendricks (dhendrix) > > Systems Software Engineer, Google Inc. > > > > -- > > coreboot mailing list: [email protected] > > http://www.coreboot.org/mailman/listinfo/coreboot > > > > Hello! > This is well and good David. Thank you! > And as it happens Google Mail goofed on its spam scanning, and even > mistook this one for a phishing scheme. According to other folk at > Google they themselves obviously use the Google Mail service > internally, so I do not see why this would have happened. > Weird! Maybe it's because of the external website link in my post. Thanks for catching that, Gregg. For reference, the public doc I referenced is available from AMD's main developer manual site: http://developer.amd.com/DOCUMENTATION/GUIDES/Pages/default.aspx The doc I referred to is here: http://developer.amd.com/assets/43366_sb7xx_bdg_pub_1.00.pdf . It's pretty vague, though. The register reference guide ( http://developer.amd.com/assets/43009_sb7xx_rrg_pub_1.00.pdf ) has some additional information on how to enable and utilize the BIOS RAM area for those curious.
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