Subject: com rumblings...
To: None <>
From: Garrett D'Amore <>
List: tech-kern
Date: 06/14/2006 00:04:44
I'm in the process of hacking up a com.c that has an #ifdef
COM_USE_REGMAP that does register remapping.  (I.e. actual register
offsets are located in an array in the softc.)  This would be
conditionally compiled, to minimize impact on VAX, i386, m68k, etc.

What this would do is let me get rid of custom aucom.c, and weird bus
space mapping logic ( a custom bus space just for this chip!) in
com_arbus.c.  I'm also hoping this will resolve a bug in aucom.c.

One question cropped up though.  I noticed that if COM_HAYESP is
defined, the probe for a HAYESP device is used, which just uses the ISA
trick of writing to special ports.

This is fine for ISA, but it is a really bad idea on other busses, e.g.
PCI where writing to the named addresses might result in a system crash
or other unexplainable behavior on non-i386 systems.

I'd like to move this code to com_isa.c, if we can confirm that it
really is ISA specific.  I.e., are there PCI or PUC devices that match
this logic?  I _suspect_ the answer is _no_, but I'm interested to hear
more specific details.

Any objection with relocating the HAYESP support to com_isa.c (still
leaving it #ifdef COM_HAYESP, of course)?

Garrett D'Amore, Principal Software Engineer
Tadpole Computer / Computing Technologies Division,
General Dynamics C4 Systems
Phone: 951 325-2134  Fax: 951 325-2191