[U-Boot] Hangs at relocation on 460EX Target

[Stefan Roese <sr@denx.de>]

Felix,

On Thursday 23 October 2008, Felix Radensky wrote:
> I had the same problem with u-boot-1.3.4 on custom 460EX board with
> registered SODIMM. The SPD code in 4xx_spd_ddr2.c (program_copt1())
> checks two  SPD fields to decide whether DIMM is registered: DDRII DIMM
> type (offset 20) and SDRAM module attributes (offset 21).
>
> In my case, the values in these fields do not match what code is looking
> for.
> See http://www.micron.com/products/spddetail.aspx?part=MT9HTF6472RHY-667F1
> I had to modify the following peice in program_copt1() to make it work:
>
>             if (dimm_num == 0) {
>                 if (dimm_populated[dimm_num] == SDRAM_DDR1) /* DDR1 type */
>                     mcopt1 |= SDRAM_MCOPT1_DDR1_TYPE;
>                 if (dimm_populated[dimm_num] == SDRAM_DDR2) /* DDR2 type */
>                     mcopt1 |= SDRAM_MCOPT1_DDR2_TYPE;
>                 if (registered == 1) { /* DDR2 always buffered */
>                     /* TODO: what about above  comments ? */
>                     mcopt1 |= SDRAM_MCOPT1_RDEN;
>                     buf0 = TRUE;
>                 } else {
>                     /* TODO: the mask 0x02 doesn't match Samsung def for
> byte 21. */

So it seems already to be know that here is a problem.

>                     if ((attribute & 0x02) == 0x00) {
>                         /* buffered not supported */
>                         buf0 = FALSE;
>                     } else {
>                         mcopt1 |= SDRAM_MCOPT1_RDEN;
>                         buf0 = TRUE;
>                     }
>                 }
>             }
>
> I've changed
>
> if ((attribute & 0x02) == 0x00)
>
> to be
>
> if (((attribute & 0x02) == 0x00) && (attribute != 0x04))

Why did you change it this way? Which DDR2 module are you using? And what's 
the value of SPD register 21?

> I'm not sure this is generic enough to go into mainline, but if yes,
> I can try to submit a patch.

We should try to provide a generic fix now. Unfortunately I don't have the 
time right now to dig into the DDR2 SPD definitions and the different 
implementation for different brands (Micron, Samsung...). Perhaps somebody 
else could check what the correct check for registered DIMM is.

Thanks.

Best regards,
Stefan

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