From owner-freebsd-sparc Tue Aug 10 15:14: 3 1999 Delivered-To: freebsd-sparc@freebsd.org Received: from mail.rwth-aachen.de (mail.RWTH-Aachen.DE [137.226.144.9]) by hub.freebsd.org (Postfix) with ESMTP id 832D51508F for ; Tue, 10 Aug 1999 15:13:46 -0700 (PDT) (envelope-from gh046171@post.rwth-aachen.de) Received: from post.rwth-aachen.de (s4m229.dialup.RWTH-Aachen.DE) by mail.rwth-aachen.de (PMDF V5.1-12 #D3869) with ESMTP id <01JEMDP8Y1XU0004F7@mail.rwth-aachen.de> for freebsd-sparc@freebsd.org; Wed, 11 Aug 1999 00:14:11 +0200 Date: Wed, 11 Aug 1999 00:13:09 +0200 From: Gerald Heinig Subject: Fwd: Boot PROM functions To: freebsd-sparc@freebsd.org Reply-To: heinig@hdz-ima.rwth-aachen.de Message-id: <37B0A3F5.3825ACE7@post.rwth-aachen.de> Organization: Institute of Computer Science in Mechanical Engineering MIME-version: 1.0 X-Mailer: Mozilla 4.6 [en] (X11; I; FreeBSD 3.1-RELEASE i386) Content-type: text/plain; charset=us-ascii Content-transfer-encoding: 7bit X-Accept-Language: en Sender: owner-freebsd-sparc@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Hi folks, here's another piece of the puzzle that's fallen into place for me. I thought I'd share it :-) Gerald > Gerald Heinig wrote: > > > I have a question on Openboot Proms. As I understand it, when the > > machine boots, the Forth monitor checks all the installed devices, > > buses, cards etc and creates a device tree. It also calls each card's > > selftest routine (on SBus, at any rate). My question is: does this > > device tree get passed to the kernel which is then booted, or does the > > kernel do the whole thing over again for itself? > > I know that on Solaris x86 the monitor creates a device tree for all > > devices found and then passes the results of this probe to the program > > that is subsequently booted (normally the kernel, obviously). Presumably > > the Openboot monitor does this on Sparc machines too. Does it? > > > > I'll assume the answer to the question is yes. How, exactly, does this > > device tree get passed to the kernel? Are the data structures/parameter > > passing mechanisms documented anywhere? > > > > The OBP stuff is now an IEEE standard - IEEE 1275. Start at > http://playground.sun.com/1275/ for info on this. > > Solaris has an IEEE 1275 prom interface that the kernel uses to > make use of prom services. Among these is the facility to > receive the device tree as constructed by the prom. > The prom library used by the kernel is an IEEE 1275 > *implementation* - it's not documented itself. > > > Also, when the kernel boots ie. when the "Copyright Sun Microsystems > > .."etc etc stuff comes up with the little rotating bar, does the kernel > > use the prom routines to output its messages, or does it at this stage > > already use its own video drivers? > > > > Very early in boot we call prom_init() which sets the kernel > up to be able to use the prom services. One of the services > is prom_printf, and very early boot messages (and error messages > if any) are produced with this. > > Cheers > > Gavin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-sparc" in the body of the message