[U-Boot-Users] SDRAM initialization process - U-BOOT1.1.1

Jerry Van Baren gerald.vanbaren at smiths-aerospace.com
Mon Jan 30 23:39:32 CET 2006

ronen no wrote:
> Hello,
> we are in the process of initializing the SDRAM refresh procedure with 
> MPC8260.
> As we get started, we have seen that u-boot.1.1.1 code includes two 
> functions
> which includes:
> board/mpc8260ads/mpc8260ads.c   initdram()
> cpu/cpu.c                                    upmconfig()
> we have seen that initdram() is called from  init_func_ram() in 
> board/lib_ppc/board.c
> Also, init_func_ram() is a function pointer in the array init_sequence[].
> we have not seen that the function upmconfig() is ever called for 
> MPC8260ads, and
> we would like to know whether we should call it.
> Currently, we have the u-boot1.1.1 reaching the relocate_code to the 
> point where
> the kernel image is copied from Flash to SDRAM, but the image in the 
> SDRAM is corrupted.
> The question is: is there a bug in the mpc8260ads that does not call the 
> upmconfig()
> or we should not call it at all?
> Looking forward for your input.
> Regards,
> Ronen

The SDRAM is controlled by the SDRAM machine which is initialized by 
initdram().  The UPM machine is not used to control the SDRAM (at least 
in any 82xx system I'm aware of), so not calling upmconfig() is not an 
error unless your board uses the upm for something (sounds like not).

You probably have a problem in your SDRAM initialization: this is a 
tough area to set up correctly because it depends on your SDRAM and 
other hardware.  Make sure your initialization matches the 
manufacturer's recommended initialization.



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