[U-Boot] [PATCH 3/6] serial: Reorder serial_assign()

Allen Martin
2012-10-22T17:23:27Z

On Sat, Oct 20, 2012 at 01:19:00AM -0700, Marek Vasut wrote:
> Dear Allen Martin,
>
> [...]
> >
> > Hi Marek, the change to return value here broke serial output on
> > tegra. What I see is that the serial device name (s->name) is
> > "eserial0" as set by serial_ns16550.c, and the name passed in from the
> > stdout environment is "serial" so they don't match and it fails. This
> > always used to be ok because the return code didn't indicate failure
> > and iomux_doenv() would continue on happily, but now it causes
> > iomux_doenv() to fail and no printfs() work after that.
> >
> > Not sure what the right fix is, should stdout really be set to
> > "eserial0"? It seems "serial" should mean "the default serial device"
> > which for the normal case is the one and only device.
>
> Looking at the source, the obvious course of action is to fix iomux.c .
>

I've been looking at this call to serial_assign() from iomux.c and I'm
not convinced this code does anything meaningful at all. It passes
the name of a struct stdio_dev device which serial_assign() then tries
to match against the registered struct serial_devices, which will
never match.

What I don't understand is the case where you have a board that
actually has more than one physical serial port and how the mapping
from stdio_dev to serial_device happens.

Also, looking at the code to cmd_nvedit, I think your change also broke
"setenv stdout" for boards that don't define CONFIG_CONSOLE_MUX. We
always have this on for tegra, so we don't go down this code path, but
it looks identical to the code in iomux.c

-Allen
--
nvpublic