kgdb and GetDebugChar/PutDebugChar

kgdb and GetDebugChar/PutDebugChar

[Brown, David (dbrown03)]

Re: http://lists.linuxppc.org/listarcs/linuxppc-dev/200003/msg00097.html

When KGDB is enabled, no GetDebugChar/PutDebugChar functions exist.
The answer given in the message above was that you have to write your own,
based on the hardware.

Surely, someone here has done that for the ppc8xx, using maybe SMC2?
Shouldn't such functions be in 8xx_io/uart.c?
If SMC2 is used for KGDB, I assume it shouldn't be included in rs_table?
--
Dave Brown <dbrown03@harris.com>

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: kgdb and GetDebugChar/PutDebugChar

[Dan Malek]

"Brown, David (dbrown03)" wrote:

> When KGDB is enabled, no GetDebugChar/PutDebugChar functions exist.

If KGDB works in the rest of the kernel, the functions are there.


> Surely, someone here has done that for the ppc8xx, using maybe SMC2?

It exists in the MontaVista 2.2.13 kernel, and in the 2.3.99 kernel.
The latter is better because it starts very early in the boot, and
you can debug almost anything in the kernel (except stepping over
instructions that disable the interrupts).  I will back port the
2.3.xx into the 2.2.14 kernel shortly, or you can do it and send
me the patches.

It uses SMC1 because it is convenient, and it allows debugging
data comm or other features that use SMC2.  When you boot a kernel
that uses KGDB, you provide the initial console input to the Linux
prompt, then disconnect your terminal emulator from the serial port,
and start up GDB on the serial port.

You can also use XMON, which is sometimes more useful that gdb.



	-- Dan

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