[coreboot] [PATCH] RAM detection for 440BX

[Keith Hui]

On Sat, Mar 6, 2010 at 2:01 PM, ron minnich <rminnich at gmail.com> wrote:

> This activity is really impressive. It got me to wondering: how old is
> the 440bx chipset? I know it's been around a while. It sure seems to
> live one ...
>
> ron
>

Yup, 440BX is alive and well. :-)

I got scored by romcc again in the battle to complete its support.

Attached is my working copy of src/northbridge/intel/i440bx/raminit.c with
more or less complete SDRAM support at 100MHz. There is one problem: romcc
segfaults on it. Because of this, it is not patch ready. It compiles fine on
gcc for my test jig. Anything I added to make it compile for my jig did not
cause this, as I removed them all and it still segfaults.

Any help is again appreciated.

There is also preliminary work done to combine

    sdram_set_registers();
    sdram_set_spd_registers();
    sdram_enable();

into sdram_initialize(), like i82830. I also added a parameter to it for the
motherboard's FSB, so the motherboard romstage can get the FSB off the clock
chip and pass it to raminit.c where SDRAM timings are programmed.

I ended up just dumping the configuration space with three 256MB PC133 DIMMs
installed in all kind of combinations and analyze that. I tested this code
by comparing its output through my test jig with my collected dumps.
SerialICE still not involved. :-)

Joseph, the code to initialize the DIMMs are already there before I came
onboard. Instead of sending the sequence to one row at a time, the 440BX
code sends one command to all populated DIMM rows together. I figure we
could save some execution time as this method is not unlike boiling 8 eggs
all at once.

By the way where in the source tree would one put code to initialize
non-DRAM related aspects of northbridge?

Thanks
Keith
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