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From: Detlev Zundel <dzu@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] Question about baud rate
Date: Thu, 17 Nov 2011 21:11:24 +0100	[thread overview]
Message-ID: <m2k46yo6fn.fsf@ohwell.denx.de> (raw)
In-Reply-To: <2dd51a0f2a27d2e09f887ca0bc497804@stevens.edu> (djantzen@stevens.edu's message of "Thu, 17 Nov 2011 13:12:16 -0500")

Hi Dan,

>> Why doe you want to setup this parameters "from the outside"?  Really
>> only the serial device used for a console needs to be setup by
>> firmware.  All other serial devices should be initialized by the user
>> space programs using them.
>
> I would like my startup script to cat messages to ttyS1, as well as to
> the console (ttyS0). Basically for the purpose of informing users that
> the firmware cannot execute for some reason (we don't like to give
> access to the console). I was trying to avoid including stty or
> setserial, but if this is the accepted way to configure the serial
> port it's not a big deal ;-)

Personally I believe that every software task should setup as much as
possible from what it knows to be needed for its own work.  For a serial
program this includes setting the baud rate and the communications
parameter like 8/n/1.

>>> For each of the three uarts, the device tree has the following line:
>>>
>>> current-speed = <0>; /* Filled in by U-Boot */
>>
>> Checking current U-Boot code, I believe this comment is simply
>> wrong. I
>> cannot see any part in the canyonlands / or generic 4xx
>> infrastructure
>> that fixes up these properties.  Maybe Stefan can comment on this
>> though.
>>
>
> Interesting...I also tried manually entering a value here, but it
> didn't seem to have any effect. Maybe it just isn't used?

This may very well be the case.  An answer can probably be found on the
linux ppc mailing list[1] ;)

>>> Sorry for the silly question!
>>
>> I don;t think its a silly question, but I also think that you do not
>> need the configuration ;)
>>
>> Cheers
>>   Detlev
>
> Thanks for your response!

You're welcome!
  Detlev

[1] http://dir.gmane.org/gmane.linux.ports.ppc64.devel
    "PowerPC developers ML" <linuxppc-dev@ozlabs.org>

-- 
Every time history repeats itself the price goes up.
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DENX Software Engineering GmbH,      MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich,  Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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      reply	other threads:[~2011-11-17 20:11 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-14 17:55 [U-Boot] Question about baud rate djantzen
2011-11-17 17:50 ` Detlev Zundel
2011-11-17 18:12   ` djantzen
2011-11-17 20:11     ` Detlev Zundel [this message]

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