[U-Boot-Users] DDR SDRAM in DIMM module for Yosemite-likePPC440EP board.

[Ben Warren]

On Fri, 2006-10-20 at 09:23 -0700, Leonid wrote:
> On Friday, October 20, 2006 9:04 AM Ben Warren wrote:
> 
> > SPD_EEPROM is not a bootstrap EEPROM.  It's an I2C eeprom on the DIMM
> > itself that is filled in by the manufacturer to include all sorts of
> > timing and configuration information.  You should use this whenever
> > possible because in theory it makes DDR DIMMs plug & play.  This of
> > course assumes that your controller is wired and laid out properly and
> > that your spd_eeprom parsing code works...
> 
> [Leonid] I see, that may be it - this way u-boot may be workable. Is it
> the only way to work with DIMM module? How I can initialize such SDRAM
> inside BDI2000 config file? Because I cannot use WORKSPACE otherwise and
> code burning takes long time... 

Of course you don't have to use the SPD stuff, but you should.  If the
BDI won't work as-is, you need to learn more about your DDR controller
and your particular DIMM's timing information, both of which should be
readily available.  While DDR control is fairly complicated, there
aren't that many knobs to turn and you may get lucky early on.

Another approach that's less systematic is to get U-boot working, dump
the DDR controller register contents and use those in your BDI config
file.  This will involve a few painful workspace-less flash burns,
though...  You can save a bit of pain by stripping your U-boot image to
bare-bones.

Sorry there's no easier answer, but if your hardware is wired right
you'll probably nail this quickly.

regards,
Ben