[U-Boot] U-Boot Timer Qualification

Mike Frysinger vapier at gentoo.org
Tue Apr 28 17:53:18 CEST 2009


On Tuesday 28 April 2009 09:41:07 Wolfgang Denk wrote:
> In message Mike Frysinger wrote:
> > i too would prefer a POST case that can be classified as a mathematically
> > sound proof.  did i miss something, or was such a case proposed ?
>
> No.
>
> And I think it's actually difficult  to  implement,  as  it's  highly
> system-dependent.  Testing against the RTC was mentioned - there is a
> plethora of different RTC being usedon different  boards,  some  more
> and  some less suitable for such a test. Some board don't even have a
> RTC (quite alot of them actually), and other systems have an internal
> RTC that runs from the same clock as the main CPU so you can  measure
> anything  but  you  cannot  measure wallclock times because you don't
> have an independent reference clock.
>
> Yes, being able to test sucha thing is nice, but I want to make clear
> that this is not a mandatory prerequisite to get any code accepted.

i proposed any RTC POST as a method of being able to somewhat validate things 
sanely, not as a complete or required solution.  i know that RTCs are not a 
given in the embedded world, but they are common enough that you should 
hopefully have a board with one to validate *arch* changes and give you an 
idea that things should be working.  pretty much all Blackfin boards from ADI 
have an RTC on it with a dedicated crystal, so it makes things easy for me.
-mike
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