[U-Boot] [RFC] ARM: omap3: Add option to disable errata workarounds.

[Andreas Bießmann]

Hi Andreas,

On 07/09/2013 11:10 AM, Albert ARIBAUD wrote:
> Hi Andreas,
> 
> On Tue, 09 Jul 2013 10:08:10 +0200, Andreas Naumann <dev at andin.de>
> wrote:
> 
>> Hi,
>>
>> It seems that all three ARM errata workarounds done in omap3 board-init 
>> (#454179 #430973 #621766) are solved/not longer needed e.g. in the 
>> AM/DM37xx chips. Other people have noticed this:
>> http://e2e.ti.com/support/arm/sitara_arm/f/791/t/254742.aspx
>>
>> When still applying them (especcially #430973), lots of segmentations 
>> faults and other strange stuff begin to appear.

I read your link the other way round. If the #430973 errata fix is _not_
applied to r3p2 it gives a lot of segfaults. Unfortunately the thread
has noc more information on that.

>> So as a simple solution I propose adding a config option to remove these 
>> workarounds for boards/silicon that dont need them. Is this sensible or 
>> should there be more automatism?
>>
>>
>> regards,
>> Andreas
>>
>>
>> PS. Does anybody have the "ARM Core Cortex-A8 (AT400/AT401) errata" 
>> document to make sure my assumption above holds true?

I have rev 20.0 from 13-Apr-10. The three mentioned errata should be
fixed in r2p1.

<snip>

> Two remarks:
> 
> 1. I would prefer the option to be the other way around, i.e. forcing
> the inclusion of the workaround when defined rather than when not
> defined; e.g. CONFIG_SYS_CORTEXA8_WORK_AROUND_ERRATA
> 
> 2. (if applicable) I would prefer erratum-specific options, e.g.
> CONFIG_SYS_CORTEXA8_WORK_AROUND_ERRATUM_430973 -- ok, "ERRATA" will be
> fine too; what I want is easing the search for errata by number.

I join Albert's suggestion. Another solution could be to read the
silicon revision and enable erratum workarounds on that information. It
would be a step towards single binary.

Best regards

Andreas Bießmann