Re: Redboot hanging during boot on EP9302

[Andrew McKay <amckay@iders.ca>]

Jonathan Larmour wrote:
> Hi Andrew,
> 
> You misaddressed this to ecos-devel-owner instead of ecos-devel. I've 
> CC'd it to ecos-devel for you in case anyone can help.

Thanks, silly me.

> 
> For what it's worth, in the 9 times out of 10 it works, is it solid? 
> Might it be worth trying out the eCos "heaptest" test (perhaps 
> increasing the iterations) to verify the stability of SDRAM in case the 
> timings are marginal?

It appears after sending this I ran across the problem.  I double checked the 
Errata for the EP9302 Rev2 part and found something wrong with the SDRAM controller.

 From Cirrus' Errata sheet:

----------------------------------------------------------------------------
When the SDRAM controller is configure for PRECHARGE ALL commnd, the actual 
sequence is not always issued to the SDRAM device(s).

Workaround:

Do a read from each SDRAM bank so that a PRECHARGE command is issued ot each 
bank of the SDRAM device.  This will satisfy the required SDRAM initialization 
sequence.

Due to the effectiveness and simplicity of the software workaround, no silicon 
fix is planned.
----------------------------------------------------------------------------

I made modifications as necessary to the SDRAM init code and all is well it appears.

Thanks for your time,
Andrew McKay