[Buildroot] can't create /dev/ttys0 on cirrus ARM EP93XX

[Thomas Petazzoni]

Hello Anthony,

On Sat, 7 Aug 2010 17:10:42 +0100
anthony henderson <development at fair-games.com> wrote:

> So I've ran buildroot for the ARM 920T.  All seems fine.  As the board has
> no keyboard ect development is done via serial port.  This is set in the old
> rootfs from etc/initab via
> ttyAM0::askfirst:-/bin/sh

Correct.

> I tried to start the new rootfs, but it appears to want to start from video
> command prompt.  So I copied the inittab from the old working system to the
> new rootfs, this gave an error finding ttyAM0.

Just modify Buildroot /etc/inittab instead.

> On searching the new rootfs I can see dev doesn't have this node.

Yes, it must be created. So, add the following line to
target/generic/device_table.txt:

/dev/ttyAM     c       666     0       0       204     16      0	1       4

It will make that /dev/ttyAM0, /dev/ttyAM1, /dev/ttyAM2 and /dev/ttyAM3
are created when building the root filesystem.

If you want to automate the adaptation of the /etc/inittab, just add an
entry in target/generic/Config.in.

Regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com