Add board enable for ASUS P4SC-E

I does this by setting bits 3..2 of register 0x24 on the ITE IT8707F,
while keeping bit 3 of register 0x23 set while manipulating the first
register.

AFAIK, there is no public datasheet available for this super i/o chip, but
the above is how the vendor BIOS does it. Also, registers 0x23 and 0x24 seem
to have the same meaning as on the ITE IT8710F.

Matching on NB/SB.

Tested on a P4SC-E with SST 39SF020A flash. Probe, read, erase, write
all work.

lspci/superio output:
http://www.flashrom.org/pipermail/flashrom/2010-July/004090.html

flashrom output:
http://www.flashrom.org/pipermail/flashrom/2010-August/004566.html

Many thanks to Reinder de Haan for help with reverse engineering this!

Corresponding to flashrom svn r1161.

Signed-off-by: Mattias Mattsson <vitplister@gmail.com>
Acked-by: Uwe Hermann <uwe@hermann-uwe.de>
2 files changed