From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758654AbXKLMT0 (ORCPT ); Mon, 12 Nov 2007 07:19:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753144AbXKLMTS (ORCPT ); Mon, 12 Nov 2007 07:19:18 -0500 Received: from mx1.redhat.com ([66.187.233.31]:37450 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752858AbXKLMTR (ORCPT ); Mon, 12 Nov 2007 07:19:17 -0500 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20071111164244.52a17203@the-village.bc.nu> References: <20071111164244.52a17203@the-village.bc.nu> <20071111151835.7917a565@the-village.bc.nu> <20071110200935.60d375de@the-village.bc.nu> <20071109195303.edbdc631.akpm@linux-foundation.org> <20071109153432.20803.69832.stgit@warthog.procyon.org.uk> <20071109153458.20803.10594.stgit@warthog.procyon.org.uk> <24343.1194697130@redhat.com> <1658.1194792517@redhat.com> <2414.1194799004@redhat.com> To: Alan Cox Cc: dhowells@redhat.com, Andrew Morton , torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, linux-am33-list@redhat.com Subject: Re: [PATCH 5/6] MN10300: Add the MN10300/AM33 architecture to the kernel [try #5] X-Mailer: MH-E 8.0.3+cvs; nmh 1.2-20070115cvs; GNU Emacs 23.0.50 Date: Mon, 12 Nov 2007 12:19:04 +0000 Message-ID: <4094.1194869944@redhat.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Alan Cox wrote: > > Some are part of the CPU core and affect things like CPU core itself, CPU > > caches, MMU/TLB and exceptions/interrupts. Others are on-silicon devices > > such as the serial ports, the bus controller, the SDRAM controller. > > How are they addressed - as CPU registers or as memory/IO space ? Well, they're all accessed as memory locations within a special range of addresses (all of 0xCxxxxxxx and 0xDxxxxxxx). This includes the magic CPU registers. This is hard coded by the CPU before the MMU gets its hands on the addresses, AFAIK. I also wondered what about the boot wrapper (the kernel decompressor): Is that permitted to use readb() and co? David