[U-Boot] RAM Probing for ads5121rev4

m marx mmarx at silicontkx.com
Wed Apr 1 12:15:08 CEST 2009


Hello Michele De Candia
Besides using a CPLD register - I thought perhaps this would be a great application for using one of the 256 user programmable fuses.  Unfortunately -- this ads5121 rev has this feature disabled for now.

John Rigby will be re-submitting those 2 patches along with a slew of others including hibernation (requiring the Elpida patch to be slightly bigger) which he is getting ready for his next BSP release.

-Martha

-----Original Message-----
From: Michele De Candia (VT) michele.decandia at valueteam.com
Sent 3/31/2009 5:37:16 PM
To: Wolfgang Denk wd at denx.de
Cc: Emanuele Placidi emanuele.placidi at gmail.com, u-boot at lists.denx.de, Martha Marx mmarx at silicontkx.com
Subject: Re: [U-Boot] RAM Probing for ads5121rev4

Wolfgang Denk wrote:
 Dear "Michele De Candia (VT)",

 In message 49D23E30.4060205 at valueteam.com you wrote:

 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?


 Yes, of course it is possible to solve this problem otherwise.

 In a sane hardware design you can read this information from some
 board configuration register or so; for example, on the ADS5121 there
 could be such a register implemented in the CPLD. But alas, there
 ain't none.

 Martha Marx posted pretty good patches (identifyung board revisions
 based on the MAC address) more than a month ago, but then failed to
 address the last review comments.

 If you want to get that fixed, please pick up her patches (or nudge
 her to do it for you).

Hi Mr. Denk,
thanks for the suggestions, we've already picked up Martha Marx patches 
and they work fine on ADS5121.
We want to avoid DDR identification by board revisions because we don't 
know which DDR will be used in the future and it isn't a flexible way to 
do that.
After all, if it is the only way, we'll use this one.

Thanks,
Michele De Candia
 Best regards,

 Wolfgang Denk




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*Michele Jr **De Candia*

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