[U-Boot-Users] Re: Moving u-boot location in ram to do full mem-test?

Martin Egholm Nielsen martin at egholm-nielsen.dk
Wed Nov 23 09:42:53 CET 2005

>>I'm using "mtest" to test the sdram somewhat, but parts of the ram is 
>>ofcourse left untested doing so - due to stack- and u-boot positioning.
> Not to forget exception vectors.
Oki :-)

>>So, I would like to make a new u-boot binary that offered me the 
>>possibility to test the first part - from "0x0" to "0x108F" and from 
>>"0x3f8af37" to "0x3ffffff".
> Ummm... I seriously doubt  if  this  is  worth  the  effort.  Typical
> problems  like  unconnected  or  shorted  data  or  address  lines or
> crosstalk will show up very reliably with the existing test. 
But couldn't there be an error for a specific address segment - say 
"0x3ff0000"-"0x3ff00ff", which contains u-boot data never being used in 
u-boot, and not possible to test with mtest?

> And the really  nasty  problems  usually happen with burst mode
> accesses, and these are *not* covered by any such memory test at all.
> In my opinion the test as is is good enough  as  is  to  find  coarse
> problems, and if you really want to stress test your memory just boot
> Linux  with  root  file  system  mounted over NFS and compile a Linux
> kernel on the target. No smiley here, I really mean it.
Yes, but that would take days, if at all possible, on my 133 Mhz 
PPC405EP with 32 megs.

Then, I would rather have a "similar" memory exhausting test-application 
for Linux...

  Martin Egholm

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