lkml.org 
[lkml]   [2002]   [Jul]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectSerial core problems on embedded PPC
I've been trying to get the new serial core stuff working on a PPC 4xx
machine (an EP405 board, specifically). This is proving more
difficult than I expected.

In 8250.c, it appears that in order for a port to be used for the
serial console it must be defined "old style" with SERIAL_PORT_DFNS,
rather than being registered with register_serial() (because
serial8250_console_setup() indexs into the serial8250_ports array)).
This presents a small problem for 4xx, since it's serial ports are
memory mapped and the new old_serial_port structure can't represent
these. I added support for these into 8250.c, but ran into further
troubles.

The kernel now gets into an infinite loop when trying to open
/dev/console in init(). The loop is occuring in tty_open() - the open
fails and it loops back to the retry_open: label. This seems to be
happening because the uart_port structure is ending up with the type
field set to PORT_UNKNOWN. However, I'm getting confused attempting
to work out where this field ought to be set, and why it isn't.

The current plethora of similar-but-not-the-same structures describing
serial ports (serial_state, serial_struct, uart_port, old_serial_port)
is also rather confusing. I'm guessing some of these are deprecated
and remain only as an aid to transition, but I'm not sure which.

--
David Gibson | For every complex problem there is a
david@gibson.dropbear.id.au | solution which is simple, neat and
| wrong.
http://www.ozlabs.org/people/dgibson
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:22    [W:0.097 / U:0.760 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site