Le 17/12/2010 04:05, Jason Liu a écrit :
There is pretty much different with I.MX51 ROM, we will not use DCD data file to config the DDR script since ROM has the DCD size limitation and use the advance feature of what we called plug-in, the plug-in code must be in the first 2K of MMC card from 0x400 offset, that's why we need put this code section before start.S.
This implication is simply not true, as far as I can tell. You do need to have this "plug-in" (will you explain in the end what it is exactly?) in the first 2K of MMC; but that does not mean it has to be put in u-boot and u-boot stored at start of MMC. You could just as well put the "plug-in" alone in the first 2K and u-boot from the second 2K onward, for all I understand:
The plug-in code will be called by boot ROM to do DDR init first and copy u-boot to DDR and jump to _start to run it.
If it has to copy u-boot to DDR, then it should ne be part of u-boot.
Does anyone of expert like you and Albert and Wolfgang tell me how to do it? It's very important for FSL coming many SOCs support, since we will use plug-in feature of boot ROM.
The first thing, I think, would be to get back to gathering your exact requirements, and only those, as per your SoC specs. From what you say of these, the requirements are not "have u-boot start in the first 2K of MMC with the "plug-in' coming first", but "have some routine in the first 2K of MMC, said routine assumed to do DDR init and payload copy"; and then, start from these reqs *only*.
Amicalement,