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

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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