[coreboot] v3 and partially memory-mapped ROMs

Carl-Daniel Hailfinger c-d.hailfinger.devel.2006 at gmx.net
Mon Aug 4 13:58:47 CEST 2008

On 04.08.2008 12:41, Stefan Reinauer wrote:
> Carl-Daniel Hailfinger wrote:
>> Hi,
>> this problem has been mentioned by me in the past, but I'd like to
>> remind people of it now that we're working on a M57SLI port to v3.
>> The LAR code and lots of other places can't cope with partially mapped
>> ROMs. There are two options:
> Are you talking about ROMs that can not be mapped completely at all?


> Have you encountered any of these anywhere? If so I would like to know
> what systems that were.

Gigabyte M57SLI rev 2.0 uses the LPC-to-SPI translation feature of the
IT8716F which can only map the top (not a movable window!) 512 kBytes of
the SPI chip in memory space. There's an additional 128 kByte region
(from 4G-1152kB to 4G-1024kB, not movable) which is sort of a "register
space" compatibility feature. Everything outside these "standard" areas
needs to be read with explicit read commands in 3-byte chunks.

So any modded M57SLI with a chip greater than 512kB has this problem. I
tried every possible undocumented workaround to no avail, and contacted
ITE with no response.

> In any other case, the bootblock's duty is to enable full mapping of the
> chip.

Fully agreed.



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