Date: Tue, 19 Aug 2008 18:11:28 +0100 From: Matt Sealey <matt@genesi-usa.com> To: Nathan Whitehorn <nwhitehorn@freebsd.org> Cc: ppc@freebsd.org, vi0@freebsd.org Subject: Re: Efika OF problems Message-ID: <48AAFEC0.9060007@genesi-usa.com> In-Reply-To: <48AAFB31.4010702@freebsd.org> References: <4810C7A2.40206@semihalf.com> <4811C774.9000407@genesi-usa.com> <4826CEA9.7020705@semihalf.com> <4827A9A0.3030102@genesi-usa.com> <48AAED83.1090403@semihalf.com> <48AAEFC6.1050205@genesi-usa.com> <48AAFB31.4010702@freebsd.org>
index | next in thread | previous in thread | raw e-mail
The best way I can think of is to instantiate RTAS then copy the device tree then get the hell out of Open Firmware. You don't have to trash it, just stop using it after you've set up the MMU. It's not ideal; you lose a few things in the process, but they are pretty much nothing anyone is going to use anyway (certainly most of what can and should be done should be done just before/after you get RTAS and copy the device tree). -- Matt Sealey <matt@genesi-usa.com> Genesi, Manager, Developer Relations Nathan Whitehorn wrote: > Matt Sealey wrote: >> There are two problems with OF calls in FreeBSD; one is that FreeBSD >> has no >> support for a "real mode" Open Firmware - Apple's runs in "virtual mode" >> which means it has all kinds of MMU stuff set up. >> >> Solaris had the same problem and Sun fixed it by implementing a slim >> "VOF" >> on top of our real OF, which implemented the virtual mode stuff. >> >> There is very, very little point in addressing this issue in firmware and >> implementing virtual addressing inside firmware, as OF client calls are >> stupidly slow. What you need to do is get it up and running and get >> all the >> OF stuff *well* out of the way *well* before any MMU stuff is set up by >> the OS itself. >> >> NetBSD manages it somehow, I don't know how. You could have a chat with >> Frank Wille.. (see the port-ofppc@netbsd.org list) > We badly need a solution to this problem. I think the VOF route might > not be a bad one for machines with hard-to-use firmwares -- we support > runtime-switchable Open Firmware interfaces already, and we need support > for Linux FDTs as well. > -Nathanhome | help
Want to link to this message? Use this
URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?48AAFEC0.9060007>