Stefan Roese wrote:
Hi Wolfgang,
On Thursday 20 March 2008, Wolfgang Denk wrote:
This patch adds this workaround for the following 440EPx boards: sequoia, lwmon5. Others should probably follow this example.
OK, the default configs for Sequoia doesn't use shared log buffer, and the lwmon5 uses CONFIG_ALT_LB_ADDR (i. e. it puts the log buffer in OCM), so these boards will work.
But any changes to the configuration may easily break this again.
Understood.
I don't like the idea that each affected board has to fix this (probably differently) in it's board config file. I would prefer a fix (common to all affected boards) in one central location.
I don't like this either. But I have not come up with a "generic" solution till now. It's not so easy since the 440EPx SDRAM setup code is sometimes common (cpu/ppc4xx/denali_spd_ddr2.c) and sometimes board specific. And it gets even more complicated when ECC initialization is needed too. So currently I have no "better" solution as to do it in a board specific way.
As always, patches implementing a "better" more generic solution are welcome.
Thanks.
Best regards, Stefan
Hi Stefan,
Having multiple implementations of the 440EXp SDRAM setup code is, in itself, less than ideal. One alternative is to have a 440EPX board with on-board SDRAM chips fake an array of SPD bytes describing the chips, and pass it to the "denali_spd_ddr2.c" code. The SPD code then becomes the single location for the technology of how to configure the Denali SDRAM controller.
The additional benefit (for me, anyway :-) ) is having more eyeballs on the SPD code, with more opportunities for testing, bug fixing, and enhancements.
Best regards, Larry