[U-Boot] RAM Probing for ads5121rev4

[U-Boot] RAM Probing for ads5121rev4

[Emanuele Placidi]

Hi all,
   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.

   B.R.
     Emanuele

[U-Boot] RAM Probing for ads5121rev4

[Wolfgang Denk]

Dear Emanuele Placidi,

In message <7c4b93310902180021o56da8320w2084e6a8c09c9509@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.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
How many QA engineers does it take to screw in a lightbulb? 3:  1  to
screw it in and 2 to say "I told you so" when it doesn't work.

[U-Boot] RAM Probing for ads5121rev4

[Michele De Candia]

Wolfgang Denk wrote:
> Dear Emanuele Placidi,
>
> In message <7c4b93310902180021o56da8320w2084e6a8c09c9509@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*

------------------------------------------------------------------------

Value Team

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Tel. +39 0248985722
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http://www.valueteam.com

 

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[U-Boot] RAM Probing for ads5121rev4

[Wolfgang Denk]

Dear "Michele De Candia (VT)",

In message <49D23E30.4060205@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).

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"If you own a machine, you are in turn owned by it,  and  spend  your
time serving it..."    - Marion Zimmer Bradley, _The Forbidden Tower_

[U-Boot] RAM Probing for ads5121rev4

[Michele De Candia]

Wolfgang Denk wrote:
> Dear "Michele De Candia (VT)",
>
> In message <49D23E30.4060205@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
>
>   


-- 

*Michele Jr **De Candia*

------------------------------------------------------------------------

Value Team

Via Vespri Siciliani, 9
20146 Milano
Tel. +39 0248985722
michele.decandia at valueteam.com <mailto:michele.decandia@valueteam.com>
http://www.valueteam.com

 

CONFIDENTIALITY NOTICE -This message and its attachments (if any) may 
contain confidential, proprietary or legally privileged information and 
is intended only for the use of the addressee named above. No 
confidentiality or privilege is waived or lost by any mistransmission. 
If you are not the intended recipient of this message you are hereby 
notified that you must not use, disseminate, copy it in any form or take 
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please delete it and any copies of it and kindly inform the sender of 
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[U-Boot] RAM Probing for ads5121rev4

[m marx]

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




-- 

*Michele Jr **De Candia*

------------------------------------------------------------------------

Value Team

Via Vespri Siciliani, 9
20146 Milano
Tel. +39 0248985722
michele.decandia at valueteam.com mailto:michele.decandia at valueteam.com
http://www.valueteam.com



CONFIDENTIALITY NOTICE -This message and its attachments (if any) may 
contain confidential, proprietary or legally privileged information and 
is intended only for the use of the addressee named above. No 
confidentiality or privilege is waived or lost by any mistransmission. 
If you are not the intended recipient of this message you are hereby 
notified that you must not use, disseminate, copy it in any form or take 
any action in reliance on it. If you have received this message in error 
please delete it and any copies of it and kindly inform the sender of 
this e-mail by replying or go to www.valueteam.com 
http://www.valueteam.com on 'contacts'.