[PATCH 10/14] tty/serial: Add kgdb_nmi driver

[Alan Cox]

On Sun, 9 Sep 2012 21:14:12 -0700
Anton Vorontsov <anton.vorontsov at linaro.org> wrote:

> This special driver makes it possible to temporary use NMI debugger port
> as a normal console by issuing 'nmi_console' command (assuming that the
> port is attached to KGDB).

No ref counting, no tty port, no compliance with the tty behaviour.
Concept looks fine but it needs porting to reflect a kernel newer than
about 2.6.18 8)

I would take a quick look at the tty_port helpers and also check v -next
which makes the tty_port mandatory. That'll pretty much cover your needs
for locking, semantics and the like.

Alan