[U-Boot] [POST] retrieving the results in Linux ?

[U-Boot] [POST] retrieving the results in Linux ?

[Valentin Longchamp]

Hello,

In the POST documentation, it is clearly stated:

> 2) The results of tests shall be saved so that it will be possible to
>    retrieve them from Linux.

I have two questions here:

- I don't find where the result actually is saved. Was this implemented already
? Was the logbuffer intented for this (call to logbuff_log in post_log) ?

- If I was wrong for the first question (the results actually are saved), where
can I find some information about how to retrieve these results ?


-- 
Valentin Longchamp
Embedded Software Engineer
Hardware and Chip Integration
______________________________________
KEYMILE AG
Schwarzenburgstr. 73
CH-3097 Liebefeld
Phone +41 31 377 1318
Fax   +41 31 377 1212
valentin.longchamp at keymile.com
www.keymile.com
______________________________________
KEYMILE: A Specialist as a Partner

[U-Boot] [POST] retrieving the results in Linux ?

[Wolfgang Denk]

Dear Valentin Longchamp,

In message <4E146E9F.4000705@keymile.com> you wrote:
> 
> In the POST documentation, it is clearly stated:
> 
> > 2) The results of tests shall be saved so that it will be possible to
> >    retrieve them from Linux.
> 
> I have two questions here:
> 
> - I don't find where the result actually is saved. Was this implemented already
> ? Was the logbuffer intented for this (call to logbuff_log in post_log) ?

Yes.  The idea is to share the log buffer between U-Boot and Linux
(hence it's allocation at the very end of the RAM).  Of course you
need support for this feature in Linux, too.  IIRC this has not yet
made it's way into mainline.

> - If I was wrong for the first question (the results actually are saved), where
> can I find some information about how to retrieve these results ?

The plan is to share the log buffer, in both directions: Linux can
read the POST results, and U-Boot can read the last Linux messages
after a crash / reboot.  Actually, after a reboot you can read the
last messages from the _previously_ running kernel in Linux, too
(assuming there are no wraparounds, of course).

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
One difference between a man and a machine is that a machine is quiet
when well oiled.

[U-Boot] [POST] retrieving the results in Linux ?

[Albert ARIBAUD]

Le 06/07/2011 23:25, Wolfgang Denk a ?crit :

> The plan is to share the log buffer, in both directions: Linux can
> read the POST results, and U-Boot can read the last Linux messages
> after a crash / reboot.  Actually, after a reboot you can read the
> last messages from the _previously_ running kernel in Linux, too
> (assuming there are no wraparounds, of course).

Even with wraparounds, you could still be able to read the last 
messages; only overwrites would prevent it.

> Best regards,
>
> Wolfgang Denk

Amicalement,
-- 
Albert.

[U-Boot] [POST] retrieving the results in Linux ?

[Wolfgang Denk]

Dear Albert,

In message <4E15DCD4.7000608@aribaud.net> you wrote:
> 
> > The plan is to share the log buffer, in both directions: Linux can
> > read the POST results, and U-Boot can read the last Linux messages
> > after a crash / reboot.  Actually, after a reboot you can read the
> > last messages from the _previously_ running kernel in Linux, too
> > (assuming there are no wraparounds, of course).
> 
> Even with wraparounds, you could still be able to read the last
> messages; only overwrites would prevent it.

Well, what I meant was: when the new kernel produces enough boot
messages to cause a wrap-around of the log buffer, then all traces of
the previous kernel's messages will be lost.

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
When a woman marries again it is because she detested her first  hus-
band.  When  a  man  marries again, it is because he adored his first
wife.                                                  -- Oscar Wilde