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RE: MCM boot-up problems - possible filesystem or flash issues?



Hi,

>Further investigation showed that while the client
>bootloader was loading the flash image file fimage (which is 0x200018 bytes
>long) to the RAM starting at address 0xc0004000, the memory was wrapping
>around after 0x200000 bytes and the last 28 bytes were overwriting the start
>of the buffer!!

Good, a classic memory mirroring

>I think that "the problem of not being able to start the 'init' process" is
>possibly linked with this situation. If the kernel expects a separate memory
>at the 0xc0204000 address but this actually wraps around and overwrites the
>memory at 0xc0004000 when accessed, it is normal for the machine to hang
>when accessing this memory.

Yes, I agree. 

SDRAM memories are divided in 4 banks. In the MCM each bank would hence
be 2 MB. Which bank to use is selected with the BA[01] pins. If these
pins are not connected correctly you will get exactly the kind of 
mirroring that you see. I think the BA[01] pins inside the MCM is 
configured with the CONF[0-4] pins on the MCM. You should therefore
verify that these are really correclty connected. The same problem
can also occur with an incorrect R_SDRAM_CONFIG. 

Magnus Martensson (magnusmn@xxxxxxx.com) will possibly send you more
info about the magics of the CONF pins and R_SDRAM_CONFIG.

/Mikael