[U-Boot] repurposing uboot's console UART after booting

[U-Boot] repurposing uboot's console UART after booting

[CAIannello]

Hi Everybody.

I'm fooling around with a Kindle 3G. I have it setup so I can SSH to it via
Wifi, and I can also get a shell through the "accessory port" which happens
to be the UART (ttymxc0) that U-Boot uses for console IO. 

After booting, I would like to use this UART for other things besides shells
and U-Boot status.  I want to attach custom peripherals to it instead. 

I tried killing the ttymxc0's shell process from my ssh session, but another
one pops right up.

In case its not obvious, I'm new to linux, but eager to learn.  If possible,
I'd rather not rebuild/reinstall U-boot on this device.  Instead, I would
like to try to make U-Boot release the UART programatically after booting.

Any tips?

Thanks in advance for your help,
Craig






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[U-Boot] repurposing uboot's console UART after booting

[Mike Frysinger]

On Sat, Apr 23, 2011 at 9:03 PM, CAIannello wrote:
> I'm fooling around with a Kindle 3G. I have it setup so I can SSH to it via
> Wifi, and I can also get a shell through the "accessory port" which happens
> to be the UART (ttymxc0) that U-Boot uses for console IO.
>
> After booting, I would like to use this UART for other things besides shells
> and U-Boot status. ?I want to attach custom peripherals to it instead.
>
> I tried killing the ttymxc0's shell process from my ssh session, but another
> one pops right up.
>
> In case its not obvious, I'm new to linux, but eager to learn. ?If possible,
> I'd rather not rebuild/reinstall U-boot on this device. ?Instead, I would
> like to try to make U-Boot release the UART programatically after booting.

this isnt a u-boot issue.  once linux boots, u-boot has nothing to do
with things.  post your question to whoever your distro maker is.
-mike

[U-Boot] repurposing uboot's console UART after booting

[Eric Cooper]

On Sat, Apr 23, 2011 at 06:03:46PM -0700, CAIannello wrote:
> After booting, I would like to use this UART for other things besides shells
> and U-Boot status.  I want to attach custom peripherals to it instead. 
> 
> I tried killing the ttymxc0's shell process from my ssh session, but another
> one pops right up.

This has nothing to do with U-Boot.  Linux typically uses the file
/etc/inittab to specify whether to spawn login processes on serial
lines.  Look at that, along with the Linux man page for "init".

-- 
Eric Cooper             e c c @ c m u . e d u

[U-Boot] repurposing uboot's console UART after booting

[Wolfgang Denk]

Dear CAIannello,

In message <31463780.post@talk.nabble.com> you wrote:
> 
> After booting, I would like to use this UART for other things besides shells
> and U-Boot status.  I want to attach custom peripherals to it instead. 
> 
> I tried killing the ttymxc0's shell process from my ssh session, but another
> one pops right up.

CXheck /etc/inittab ...

> In case its not obvious, I'm new to linux, but eager to learn.  If possible,
> I'd rather not rebuild/reinstall U-boot on this device.  Instead, I would
> like to try to make U-Boot release the UART programatically after booting.
> 
> Any tips?

Well, try posting on a mailing list that deals with Linux questions.
This issue is in no way related to U-Boot.

Best regards,

Wolfgang Denk

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HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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