[U-Boot] RAM Probing for ads5121rev4

Michele De Candia (VT) michele.decandia at valueteam.com
Tue Mar 31 18:00:48 CEST 2009

Wolfgang Denk wrote:
> Dear Emanuele Placidi,
> In message <7c4b93310902180021o56da8320w2084e6a8c09c9509 at mail.gmail.com> you wrote:
>>    In your opinion it is possible to probe the ram before initialize it?
>> Unfortunately there are some rev4 which are equipped with different ram
>> model.
>> Examples are welcomed.
> It is a standard feature in U-Boot (and has always  been  right  from
> the start with PPCBoot nearly 10 years ago) that we auto-detected the
> memory  configuration  on  the  boards,  both for RAM and flash. Some
> boards / architectures did not bother  to  implement  this,  but  the
> feature itself is present.
> The  details  depend  on  processor,  memory  controller  properties,
> specific RAM types used, etc.
> In case of the Micron/Elpida issue on the ADS5121, that should be not
> too difficult to solve.
The issue concerns the possibility to identify DDR chips type (e.g. by 
VendorId) before initialize them.
It doesn't concern configuration parameters (size, bus frequency, ecc..).
There isn't a DDR command to read this information, do you think it is 
possible to solve this problem in other ways?
> Best regards,
> Wolfgang Denk


*Michele Jr **De Candia*


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