Re: DDR problem

[Dave Ashley]

I think this problem is configuration of Rx58 bits 7-5, you have 10/11
bit column address but it is behaving like 9 bit column address.

From looking at the code for ddr init it looks like cpu address
shifted right by 3 bits is the address going into the chip. So
accessing 0x150 is really like accessing 0x02a on the ddr chips.
Accessing 0x1000 is chip address 0x200 which overflows 9 bits.

I can get this same behaviour with to DDR rams. However when I try to
configure ddram control matching award bios settings, it works better
but fails later during vga init I think. Passes ramtest also.

-Dave
> SDRAM verify:
> 00000000:00001000
> 00000004:00001004
> 00000008:00001008
> 0000000c:0000100c
> 00000010:00001010
> 00000014:00001014
> 00000018:00001018
> 0000001c:0000101c
> 00000020:00001020
> 00000024:00001024
> 00000028:00001028
> 0000002c:0000102c
> 00000030:00001030
> 00000034:00001034
> 00000038:00001038
> 0000003c:0000103c
> Too many errors.