[U-Boot] U-boot memory test results

[Wolfgang Denk]

Dear Joe Kulikauskas,

In message <CAExZSpSd6ErzkvDEA7Y7ZFKVGPAe-H3WA0wM8+UBRjhf3rFqig at mail.gmail.com> you wrote:
>
> > I want to perform memory test (FLASH) during U-boot and read the results
> > after the operating system (Linux) is booted up.
> > Is it possible? If so, can anyone guide me to do so?
> 
> This could work by setting a u-boot environment variable with the POST
> result. It would probably require adding some u-boot code, the baseline
> puts POST results just into console output and maybe a memory loc IIRC.

this  makes no sense.  Thebest approach is , as already suggested, to
interface directly to the Linux logbuffer mechanism  this is how it
was designed from the beginning, and all prerequisites are in place
and have been working in the past.  They were just not synchronized
with the latest changes in the Linux logbuffer handling, so these
parts must be reworked.

Note that this brings a number of nice features - not only can you
handle your POST results in in Linux using standard application code
(as ypu are accessing a standard interface), but you can then also
access the Linux log buffer in U-Boot for example after a crash for
post-mortem analysis, etc.

> If you had the environment variable, then you could get result from Linux
> with fw_printenv.

This would work, but you would define a new interface for this, and
you would run into problems quickly for things like multi-line output
etc.  Not to mention that it's not a nice thing to write the
environment for every boot - it wears the flahs, and makes the system
less robust.

Best regards,

Wolfgang Denk

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