ARM, earlyconsole and io mapping

Robert Jarzmik robert.jarzmik at free.fr
Tue Mar 31 02:11:09 PDT 2015


Peter Hurley <peter at hurleysoftware.com> writes:

> Hi Robert,
>
> On 03/30/2015 08:05 AM, Robert Jarzmik wrote:
>> Hi,
>> 
>> I was wondering how the earlyconsole was supposed to work in order to add
>> support to the pxa architecture. More specifically, I don't understand how the
>> memory mapping is supposed to be available at the early parameters parsing.
> Fixmap support has not been upstreamed yet, but if you're desperate, here's
> the latest patch version:
> http://lists.infradead.org/pipermail/linux-arm-kernel/2015-January/318372.html

Ah I'm not desperate, that would be nice to have tool on my automation
platform. I've gone the DEBUG_LL + JTAG/__log_buf memory dump so far.

And yet I remember viewing early concole patches a few monthes back, and I
wondered how the authors could make them work ... And as my memory didn't serve
me well, I couldn't remember your name.

> If you're using /chosen/stdout-path, earlycon gets turned off at dummy
> VT console load, so for right now, specify your earlycon and consoles on the
> command line.
Ah I'm using device-tree in only 1/3rd of the PXA tests :
 - 1/3rd for legacy platform_data tests
 - 1/3rd for device-tree pxa platforms
 - 1/3rd for multiplatform kernel

Anyway, I hope you'll have Russell's comments addressed, and that your patch
will make it upstream. Thanks for the information, it is exactly what I was
asking for.

Cheers.

-- 
Robert



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