From owner-freebsd-hackers  Sat Dec 23 01:34:47 1995
Return-Path: owner-hackers
Received: (from root@localhost)
          by freefall.freebsd.org (8.7.3/8.7.3) id BAA28627
          for hackers-outgoing; Sat, 23 Dec 1995 01:34:47 -0800 (PST)
Received: from hda.com (hda.com [199.232.40.182])
          by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id BAA28609
          for <hackers@FreeBSD.org>; Sat, 23 Dec 1995 01:34:42 -0800 (PST)
Received: (from dufault@localhost) by hda.com (8.6.11/8.6.9) id EAA02713; Sat, 23 Dec 1995 04:44:42 -0500
From: Peter Dufault <dufault@hda.com>
Message-Id: <199512230944.EAA02713@hda.com>
Subject: Re: Help with lkm's please
To: terry@lambert.org (Terry Lambert)
Date: Sat, 23 Dec 1995 04:44:42 -0500 (EST)
Cc: pc012@svcc.seqeb.gov.au, hackers@FreeBSD.org
In-Reply-To: <199512230711.AAA21580@phaeton.artisoft.com> from "Terry Lambert" at Dec 23, 95 00:11:05 am
X-Mailer: ELM [version 2.4 PL24]
Content-Type: text
Sender: owner-hackers@FreeBSD.org
Precedence: bulk

> 
> > I am writing an lkm device driver for a digital IO board. I have worked 
> > out how to move bytes from the user space to the kernel space but not 
> > vice-versa. Can anyone give me any clues on how I move data from the 
> > kernel space to the user space. Do I use the uiomove() function, if so how.
> 
> Are you using uio structures in all cases?  If you are not required to,
> it would probably be simpler (and faster) to call copyin/copyout directly
> if you know the source/destination to be in user space and the
> destination/source to be in system space (if they are both in system space,
> use bcopy instead).
> 
> Look at the uiomove source in /sys/kern/kern_subr.c.

...

Or use a strategy function and go through physio.

The labpc driver does digital I/O to and from the board's digital
port.  That part of the driver is just a quick hack that copies
all the bytes directly to the port.  Look at "digital_in_strategy"
and "digital_out_strategy".  For something interrupt driven look
at ad_strategy.

--

Peter Dufault               Real Time Machine Control and Simulation
HD Associates, Inc.         Voice: 508 433 6936
dufault@hda.com             Fax:   508 433 5267