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

Leonid Leonid at a-k-a.net
Sun Oct 22 04:38:32 CEST 2006


On Saturday, October 21, 2006 3:19 AM Stefan Roese wrote:
> > But please note that bamboo (440EP) is not a perfect example for DDR

> > init on 440 systems, since it has one bank of DDR soldered onboard 
> > _plus_ the DIMM module(s).

> I just realized that we have another 440EP board in the U-Boot tree
that 
> matches your SDRAM setup better. The "pcs440ep". It has one DIMM
module 
> and no onboard SDRAM.

[Leonid] Actually I could make spd_sdram work for my board (our HW guy
hooked up DIMM EEPROM connections for me). I stepped through code using
debugger and found out that EEPROM (address 0x51 on our board) has been
successfully read, all parameters were sane and SDRAM registers have
been updated accordantly. However sdram0_mcsts register's most
significant bit never becomes 1, meaning SDRAM controller cannot
complete memory initialization and code stays in endless loop:

	/*
	 * wait for SDRAM_CFG0_DC_EN to complete
	 */
	while (1) {
		mfsdram(mem_mcsts, mcsts);
		if ((mcsts & SDRAM_MCSTS_MRSC) != 0) {
			break;
		}
	}

That looks like HW problem for me. Of course, I'll look through actual
registers' values more carefully - may be spd_sdram() just parsed EEPROM
parameters wrongly but I doubt that.

Just in case - did you happen to have BDI config file for that board -
brief search in the ftp://ftp.denx.de/pub/BDI2000/ directory didn't
provide results.

Best regards,
Leonid.




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