From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Sat, 29 Nov 2014 00:50:24 +0100 (CET) Received: from unicorn.mansr.com ([81.2.72.234]:54690 "EHLO unicorn.mansr.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S27007454AbaK1XuWfKpGN convert rfc822-to-8bit (ORCPT ); Sat, 29 Nov 2014 00:50:22 +0100 Received: by unicorn.mansr.com (Postfix, from userid 51770) id 89C5E1538A; Fri, 28 Nov 2014 23:50:16 +0000 (GMT) From: =?iso-8859-1?Q?M=E5ns_Rullg=E5rd?= To: linux-mips@linux-mips.org Subject: fast_iob() vs PHYS_OFFSET Date: Fri, 28 Nov 2014 23:50:16 +0000 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 44517 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: mans@mansr.com Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips I'm a little confused over the interaction between fast_iob() and non-zero PHYS_OFFSET. The __fast_iob() macro performs a load from CKSEG1. AFAICT, CKSEG1 is always (on 32-bit systems) defined to 0xa0000000. In case of a non-zero PHYS_OFFSET, this address might not map to anything in particular, and almost certainly not RAM. There is a special case for IP28, but this is not the only system with an unusual address map. What am I missing? -- Måns Rullgård mans@mansr.com