[LinuxBIOS] Clarification of Raminit.c
roger at eskimo.com
Sun May 13 11:06:30 CEST 2007
On Sun, 2007-05-13 at 01:39 -0700, roger wrote:
> I'm kind of confused on this one...
> How would I specify a DRAMC or CAS setting (after referring to the 440BX
> intel spec pdf)?
> For example:
> --- Snip from Intel pdf ---
> NBXCFG—NBX Configuration Register (Device 0)
> Offset: 50–53h
> Default: bits 31–16: 0000h
> bits 15–0: 00S0-0000-000S-0S00b
> Access: Read/
> Size: 32 bits
> 13:12 00 = 100 MHz, 11 = Reserved
> --- End Snip from Intel pdf ---
> Again, just using this as an example as values should be provided by SPD
> values. In i440bx/raminit.c, we set this with the following values:
> NBXCFG, 0x00000000, 0xff00a00c,
> I'm guessing the "0x00000000" & "0xff00a00c" values are calculated by
> somehow adding all the settings possible for NBX and somehow, the value
> is uniquely recognized by the Northbridge??
Looking at the function within raminit.c a comment reveals:
/* Table format: register, bitmask, value. */
So, I presume:
register == NBXCFG ???
bitmask == 0x00000000 ???
value == 0xff00a00c ???
Also presuming these hexadecimal word (32 bit) values were converted
from the original decimal notation.
Key fingerprint = 8977 A252 2623 F567 70CD 1261 640F C963 1005 1D61
Sun May 13 02:06:28 PDT 2007
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