[U-Boot-Users] DDR SDRAM in DIMM module for Yosemite-like PPC440EP board.

Ben Warren bwarren at qstreams.com
Fri Oct 20 18:04:21 CEST 2006


On Fri, 2006-10-20 at 08:57 -0700, Leonid wrote:
> On Friday, October 20, 2006 4:59 AM Stefan Roese wrote:
> > If you are using DIMM modules, please don't use the board specific DDR 
> > init code of the Yosemite, but the cpu specific DDR init code für DDR DIMM 
> > modules, like the other 440 AMCC eval boards do (e.g. ocotea, bamboo).
> 
> [Leonid] I'll try to do that, thank you. Yet I probably didn't make myself clear: I connect BDI2000 first whose configuration file can initialize all registers (though one can skip directly to code by "reset run" BDI command). Neither code is running in this moment (except BDI's firmware) and I expect that if BDI config file is correct, SDRAM will be available even BEFORE u-boot code takes over, but it's not: Mode Register Set Command never get completed and WORKSPACE command from config file doesn't work. I'll take a look into BDI config files for other AMCC boards - like ocotea & bamboo if I'll be able to find them.
>  
> > Please modify your U-Boot configuration to use the cpu/ppc4xx/spd_sdram.c 
> > code. The following lines should be added to your board config file (with 
> > the correct I2C addresses of course):
> 
> > #define CONFIG_SPD_EEPROM     1        /* Use SPD EEPROM for setup     */
> > #define SPD_EEPROM_ADDRESS {0x53,0x52}  /* SPD i2c spd addresses        */
> 
> [Leonid] You mean to use option G or H to read bootstrap from serial EEPROM? Or some another exercise with EEPROM I must do because I'm using DIMM module? I'll read this code to see what it does.
> 
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...

regards,
Ben





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