From: "David H. Lynch Jr." <dhlii@dlasys.net>
To: Michael Galassi <mgalassi@c-cor.com>
Cc: Robert Corley <rcorley@aegis-inc.net>,
linux linuxppc-embedded <linuxppc-embedded@ozlabs.org>
Subject: Re: uartlite with 2.6.17 kernel and kernel early text messages
Date: Sun, 15 Oct 2006 18:00:58 -0400 [thread overview]
Message-ID: <4532AF9A.50303@dlasys.net> (raw)
In-Reply-To: <200610132226.k9DMQ0xg050310@penguin.ncube.com>
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Michael Galassi wrote:
>> In an effort to get past the "Rebooting to System ACE Configuration
>> Address 6..." message, I have selected "support for early boot texts
>> over serial port" in kernel debugging.
>>
>
> This will not work. Unfortunately linux here shows its roots as PS OS,
> there is a vast amount of hardcoded NS8250/NS16550 knowledge in there.
> I'd started modularizing this so we could use a UART lite but the more I
> dug the lower my motivation. This is really ugly code in an area that
> is of virtually no interest. For now get rid of support for early boot
> texts over serial port" and use your JTAG to read the buffers if you
> panic before the console is up and running.
>
UartLite early boot text support is fairly trivial. It is also fairly
standalone.
You basically need about 5 lines of code to output a character.
David Bolcsfoldi has posted patches to Peter's driver that should work.
I have had working early boot text support long before I even had a
working driver.
There is atleast one other Uart family besides the 8250 with early
boot text support.
You can also fairly trivially fold my early boot text code into
Peter's driver.
The most disconcerting problem is the #ifdef that results with
something like 4 or cases.
The non-8250 support could be more modularized - but it still not a
major pain.
> -michael
> _______________________________________________
> Linuxppc-embedded mailing list
> Linuxppc-embedded@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-embedded
>
--
Dave Lynch DLA Systems
Software Development: Embedded Linux
717.627.3770 dhlii@dlasys.net http://www.dlasys.net
fax: 1.253.369.9244 Cell: 1.717.587.7774
Over 25 years' experience in platforms, languages, and technologies too numerous to list.
"Any intelligent fool can make things bigger and more complex... It takes a touch of genius - and a lot of courage to move in the opposite direction."
Albert Einstein
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next prev parent reply other threads:[~2006-10-15 22:04 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-13 20:44 uartlite with 2.6.17 kernel and kernel early text messages Robert Corley
2006-10-13 21:48 ` Eeek! page_mapcount(page) went negative! (-1) -2.6.16.2 kernel agnel juni
2006-10-13 22:26 ` uartlite with 2.6.17 kernel and kernel early text messages Michael Galassi
2006-10-15 22:00 ` David H. Lynch Jr. [this message]
2006-10-15 21:12 ` David H. Lynch Jr.
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