[U-Boot-Users] mtest issue on MPC8272

[Jerry Van Baren <gerald.vanbaren@smiths-aerospace.com>]

raymond yang wrote:
> Hi All,
> 
> My board got problems while running m_test, any idea, 
> 
> Looks like the high order two bytes mismatched, while
> low part correct.
> 
> Does this mean we failed to configure the SDRAM or due
> to hardwarer issue?
> 
> thanks!
> 
> Best Regards
> Raymond
> 
> 
> => mtest
> Pattern 00000000  Writing...  Reading...
> Mem error @ 0x00110000: found 00044000, expected
> 00004000
> 
> Mem error @ 0x00118000: found 40246000, expected
> 00006000
> 
> Mem error @ 0x001A0000: found 00268000, expected
> 00028000
> 
> Mem error @ 0x001B0000: found 0006C000, expected
> 0002C000
> 
> Mem error @ 0x001F8000: found 0427E000, expected
> 0003E000
> 
> Mem error @ 0x00200000: found CC320000, expected
> 00040000
> 
> Mem error @ 0x00208000: found C4322000, expected
> 00042000

Hi Raymond,

Suspicious: only one error per instance, and that on a 4KB boundary. 
Sounds like Something Bad[tm] is happening on a page boundary (e.g. page 
close, new page open).  For the common hardware faults of shorted 
address and/or data lines, you would get a whole burst of errors when 
the affected lines are exercised.

Questions:
* What is your memory configuration (x8, x16, x32)?  What is the SDRAM 
page size?
* Are these the only errors found?
* Can you use the command line to write to the error addresses and read 
back the proper values?  If not, what do you get?  Use various patterns, 
are the upper two bytes random or related to the lower two bytes?

Inquiring minds want to know...
gvb