Fix the NVRAM access functions to work correctly for the

upper 128 bytes of NVRAM (if enabled).

For most chipsets this means using I/O ports 0x72/0x73, but at least
on some VIA chipsets (I tested the VIA VT8237R on actual hardware)
these ports won't work and you have to use 0x74/0x75. Thus, make this
a Kconfig option for now.

Signed-off-by: Uwe Hermann <uwe@hermann-uwe.de>
Acked-by: Jordan Crouse <jordan.crouse@amd.com>



git-svn-id: svn://svn.coreboot.org/coreboot/trunk@3202 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
This commit is contained in:
Uwe Hermann
2008-03-31 20:21:49 +00:00
parent 2d758b8bf6
commit 30d789bcbd
3 changed files with 48 additions and 6 deletions

View File

@@ -72,6 +72,22 @@ config NVRAM
bool "Support for reading/writing NVRAM bytes"
default y
config RTC_PORT_EXTENDED_VIA
bool "Extended RTC ports are 0x74/0x75"
default n
help
For recent chipsets with 256 NVRAM bytes, you have to access the
upper 128 bytes (128-255) using two different I/O ports,
usually 0x72/0x73.
On some chipsets this can be a different set of ports, though.
The VIA VT8237R for example only recognizes the ports 0x74/0x75
for accessing the high 128 NVRAM bytes (as seems to be the case for
multiple VIA chipsets).
If you want to read or write CMOS bytes on computers with one of
these chipsets, say 'y' here.
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