using SCC4 on MPC8272ADS

Landau, Bracha BLandau at
Wed Sep 21 21:33:39 EST 2005

I reconfigured the kernel so that only SCC1 and SCC4 are supported. The same thing happens as before.
Another bit of info is that if I run with console=ttyCPM1 as a kernel command line parameter, so that u-boot outputs to one port and the kernel outputs to the other, if I type "ls > /dev/ttyCPM0" the system hangs.

-----Original Message-----
From: Vitaly Bordug [mailto:vbordug at]
Sent: Wednesday, September 21, 2005 1:56 PM
To: Landau, Bracha
Cc: linuxppc-embedded at
Subject: Re: using SCC4 on MPC8272ADS

Landau, Bracha wrote:
> I am using the MPC8272ADS with kernel 2.6.10. The kernel is configured to support 4 CPM SCCs, of which 1 and 4 are connected on the board.
> I created device files as follows:
> mknod /dev/ttyCPM0 c 204 46
> mknod /dev/ttyCPM1 c 204 47
> mknod /dev/ttyCPM2 c 204 48
> mknod /dev/ttyCPM3 c 204 49
> If I boot the kernel using console=ttyCPM3 I see that it uses SCC4. But when I boot with console=ttyCPM0 and write to the second port using a command like "echo hello > /dev/ttyCPM3" I don't see that anything is being outputted to the second console.
> What am I doing wrong?
Funny - you said that SCC 1 and 4 are connected to the board; than why 
you are enabling SCC2 and SCC3?

This board does have 2 SCCs assigned for UARTs. No need to configure 
SCC2 and SCC3 - this is useless and may lead to kernel crash. This board 
will use in the correct configuration /dev/ttyCPM0 <SCC1> and 
/dev/ttyCPM1 <SCC4>.

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