From owner-freebsd-arch Mon Jul 17 11:38:39 2000 Delivered-To: freebsd-arch@freebsd.org Received: from mass.osd.bsdi.com (adsl-63-202-177-51.dsl.snfc21.pacbell.net [63.202.177.51]) by hub.freebsd.org (Postfix) with ESMTP id 3B0EB37B761 for ; Mon, 17 Jul 2000 11:38:35 -0700 (PDT) (envelope-from msmith@mass.osd.bsdi.com) Received: from mass.osd.bsdi.com (localhost [127.0.0.1]) by mass.osd.bsdi.com (8.9.3/8.9.3) with ESMTP id LAA10760; Mon, 17 Jul 2000 11:47:23 -0700 (PDT) (envelope-from msmith@mass.osd.bsdi.com) Message-Id: <200007171847.LAA10760@mass.osd.bsdi.com> X-Mailer: exmh version 2.1.1 10/15/1999 To: Chuck Paterson Cc: arch@freebsd.org Subject: Re: removal of kvtop() on i386 In-reply-to: Your message of "Mon, 17 Jul 2000 08:41:00 MDT." <200007171441.IAA22202@berserker.bsdi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Mon, 17 Jul 2000 11:47:23 -0700 From: Mike Smith Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > > Has anybody though about how to change this for > architectures like Sparc where the whole idea of handing > a physical address to the drivers on a bus doesn't apply, and > where a unmapping/cache flushing operation must be done > at io completion. Yes. The busspace/busdma abstractions hide all of this by giving you a set of functions which translate from "virtual space" to "bus space" where the latter reflects a device on a specific buss' perception of physical memory. This abstraction includes map/unmap as well as pre and post sync hooks, functions to allocate bus-visible memory, scatter/gather list generation, etc. About the only thing currently missing is explicit support for mbuf chains, and the NetBSD folks have had code to handle that for quite some time now. -- ... every activity meets with opposition, everyone who acts has his rivals and unfortunately opponents also. But not because people want to be opponents, rather because the tasks and relationships force people to take different points of view. [Dr. Fritz Todt] To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message