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From: Terry Lambert <terry@lambert.org>
Message-Id: <199606192330.QAA14478@phaeton.artisoft.com>
Subject: Re: ?: allocating physical memory for a driver
To: msaal@qosnet.com (Michael Saal)
Date: Wed, 19 Jun 1996 16:30:36 -0700 (MST)
Cc: questions@FreeBSD.org
In-Reply-To: <31C80975.41C67EA6@qosnet.com> from "Michael Saal" at Jun 19, 96 02:06:45 pm
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> I am writing a driver for a bus mastering ISA card.
> 
> How do I allocate physical memory and make sure that is located below
> the 16M boundry addressable by the ISA bus?
> 
> Is malloc("memory size", M_DEVBUF, M_NOWAIT) sufficient? If it is I
> don't see how you can make sure the memory is in the right range with
> out testing the resulting pointer.

Look at the DMA stuff in (for instance) the aha1542 driver; it's pretty
straight-forward.  If you use the standard routines, bouncing will
be done for you.


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.