[U-Boot] How can I make a second serial port on a motorola 8248 Chip known to Linux.

From: AGKohler <ANDREWGKOHLER@gmail.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] How can I make a second serial port on a motorola 8248 Chip known to Linux.
Date: Wed, 26 Aug 2009 13:15:39 -0700 (PDT)	[thread overview]
Message-ID: <25157108.post@talk.nabble.com> (raw)
In-Reply-To: <20090825175620.GA4333@b07421-ec1.am.freescale.net>

I am using u-boot version 1.1.3, kernel, Linux(Debian) is version 2.6.12.
I searched through the kernel configuration options via menuconfig, i could
not find 
anything that configures the number of serial ports. In LINUX, i tried
creating ttyS1 with
"mknod -m 660 /dev/ttS1 c 4 65". A /dev/ttyS1 shows up in the directory
listing, but I am unable to
transmit/receive characters on it.

Thanks.

Scott Wood-2 wrote:
> 
> On Tue, Aug 25, 2009 at 08:37:11AM -0700, AGKohler wrote:
>> 
>> Hello,
>> 
>> I am working with a mpc8260ads(actually QUICC 8248 processor) based
>> board. 
>> There are two hardware rs-232 ports available. 
>> I can switch the console between the two by switching the
>> CONFIG_CONS_INDEX 
>> configuration variable between 1 and 4.
>> I would like to have both ports in service, when Linux comes up. One as
>> the
>> console and the second to communicate with(i.e. acquire data from) a
>> third
>> party rs-232 device. Eventually, the third party device may be a
>> telephone
>> modem. Can anyone explain how to accomplish this, and if not, what
>> constraints are blocking the accomplishment of my requirements. Any
>> suggestions will be appreciated.
> 
> This isn't a U-Boot issue, except insofar as U-Boot passes a device tree
> to Linux (assuming it does even that -- you don't mention which kernel or
> u-boot version you're using).
> 
> If your device tree contains both serial ports, then Linux should be able
> to use them both.  If it doesn't work, make sure all the pins are
> configured correctly, typically by Linux platform code for your board
> (though ideally U-Boot should set them up as well).
> 
> -Scott
> _______________________________________________
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> U-Boot at lists.denx.de
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> 
> 

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