mxs auart driver problems

[Zach Sadecki]

I am having some problems with the mxs-auart driver in the mainline 
kernel on my mx28 board.  If I use minicom to access the port 
(/dev/ttyAPP1) it seems to behave.  If I just send it some characters 
using 'echo -n " " > /dev/ttyAPP1'  it appears to work the first time, 
then if I repeat the same command it hangs until I kill it with ^C.

After some experimentation it seems that it only works if I'm actively 
reading characters out of it 'cat /dev/ttyAPP1' (in background or a 2nd 
terminal) and if I have turned off 'echo' using 'stty -F /dev/ttyAPP1 
-echo'.  Without the '-echo' option the serial port spews random 
characters after sending it something.

Also, when it's in the hanging state, other ttys don't behave either 
(the AMBA serial console can't respawn the login process and I can't ssh 
into the system either).  Once I ^C the hanging 'echo' command 
immediately the console login respawns and ssh login works again.

Anybody else have this problem?  The Freescale kernel (driver with DMA) 
doesn't seem to have this issue (but it still suffers from the '-echo' 
problem described above).  Any ideas on what may be going on here?

Thanks,
   Zach