Subject: Re: Converting from physical to virtual?
To: None <firstname.lastname@example.org, amiga-dev@NetBSD.ORG>
From: Daniel Widenfalk <email@example.com>
Date: 05/31/1995 12:52:13
> I'm working on adding disconnect/reselect logic to the sbic driver, and I
> need to poke a few (5-10) bytes into some random part of physical memory
> to clean up partial transfers. What's the preferred method of converting
> from a physical address to something the CPU can use to poke at memory
> with? I have some ideas, but I prefer not to create and then destroy a
> mapping just to store a half-dozen bytes. And I don't want to start
> fooling around with the CPU's registers either.
I had a similar problem when I developed my Fastlane driver and the easiest
method IMHO is to create a temporary mapping using one page. It's almost
cost-efficient and it's not much work. You could take a look in my source
(sfas.c) and see what I've done. Search for NEED_VM_FIX.