[U-Boot] Improper assumption of serial port

[Simon Glass]

Hi Vladimir,

On Sun, Apr 7, 2013 at 8:42 AM, Vladimir 'φ-coder/phcoder' Serbinenko
<phcoder at gmail.com> wrote:
> U-boot on coreboot assumes that serial port is always available and
> improperly interprets missing ones as stream of 0xff. What would be the
> proper way to handle this? Is it acceptable to probe at it's address
> whether we have a valid ns8250/ns16550 device (we can read back the
> divisor and compare with what we have set) and dropping the serial if
> none is available?

Typically we can deal with this using environment variables - e.g.
stdin/stdout. However, if there is no serial port, what is the
intended console? The VGA?

I think probing is maybe acceptable. Another way might be to create a
new device tree alongside link.dts.

Regards,
Simon