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Date:      Thu, 16 Apr 1998 11:38:46 -0700
From:      Mike Smith <mike@smith.net.au>
To:        Karl Pielorz <kpielorz@tdx.co.uk>
Cc:        hackers@FreeBSD.ORG
Subject:   Re: Memory mapping via Syscons? 
Message-ID:  <199804161838.LAA00640@dingo.cdrom.com>
In-Reply-To: Your message of "Thu, 16 Apr 1998 19:33:07 BST." <35364EE3.2043BF4A@tdx.co.uk> 

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> I've read somewhere that you can use syscons to map IO memory into
> 'userland'? Is this possible?

Yes.

> I have a simple ISA card that maps in at 0x240 - 0x24F - which I'd like to
> read and write to without going through creating a kernel device driver
> etc...

That's not memory, that's I/O space.  Open /dev/io and then use the 
functions in <machine/cpufunc.h> to perform I/O.

> A device driver will probably follow - but if I can just get to the card I
> can use a heap of existing code I've allready got to drive it - and worry
> about the driver when I have more time...

We built a commercial product using user-mode I/O that managed well 
over 1M/sec using that interface.  For many applications, there's no 
need to do anything more complex.

-- 
\\  Sometimes you're ahead,       \\  Mike Smith
\\  sometimes you're behind.      \\  mike@smith.net.au
\\  The race is long, and in the  \\  msmith@freebsd.org
\\  end it's only with yourself.  \\  msmith@cdrom.com



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