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