[U-Boot-Users] lost between in_ram and "bl board_init_r"

Antonio Di Bacco antonio.dibacco at aruba.it
Thu May 11 21:46:36 CEST 2006

Problem was solved thanks to Denk suggestions. SDRAM has an internal "mode set 
register" that can be programmed putting the desired value over the address 
lines (for example you can configure the burst length), then a special cycle 
has to be RUN on the cas, ras ... and other lines. If you have  power PC you 
have register MCR, MAR to accomplish the task. 
You put the SDRAM register value in MAR, then you use MCR to issue the RUN 
special cycle that execute a pattern on the bus lines.
Anyway you should read the SDRAM datasheet and processor datasheet.

Probably I was the only not to know this. Anyway, if someone is in trouble I 
can be more detailed.


On Tuesday 09 May 2006 21:25, Wolfgang Denk wrote:
> In message <200605091940.29621.antonio.dibacco at aruba.it> you wrote:
> > I'm trying to run u-boot 1.1.4 on a MPC880 board with 16MB ram and 8MB
> > flash. After a long porting phase now the processor has arrived to
> > relocate_code and once entered there it loops forever between in_ram
> > (start.S) and "bl board_init_r"  without calling board_init_r. The u-boot
> > seems to be corrected
> So there is a 99.999 % likelyhood that your SDRAM  init  sequence  is
> incorrect and/or incomplete.
> > relocated at 0x00FCA000, the stack seems to be correctly setup but it
> > seems that the printf in board_init_r is never called. I've also enabled
> > a CFG_DRAM_TEST and it is successfull, then I hope no DRAM problems.
> You do. You can be sure of it.
> Best regards,
> Wolfgang Denk

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