From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 1 May 2001 17:32:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 1 May 2001 17:32:35 -0400 Received: from www.linux.org.uk ([195.92.249.252]:12050 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id ; Tue, 1 May 2001 17:32:28 -0400 Date: Tue, 1 May 2001 22:31:54 +0100 From: Russell King To: Linus Torvalds Cc: linux-kernel@vger.kernel.org Subject: Re: isa_read/write not available on ppc - solution suggestions ?? Message-ID: <20010501223154.G3541@flint.arm.linux.org.uk> Mail-Followup-To: Russell King , Linus Torvalds , linux-kernel@vger.kernel.org In-Reply-To: <20010501204543.B3541@flint.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: ; from torvalds@transmeta.com on Tue, May 01, 2001 at 02:19:33PM -0700 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 01, 2001 at 02:19:33PM -0700, Linus Torvalds wrote: > On Tue, 1 May 2001, Russell King wrote: > > Talking around this issue, is there any chance of getting the > > official use of the first parameter to ioremap documented in > > Documentation/IO-mapping.txt please? There appears to be > > confusion as to whether it is: > > > > a) PCI bus address > > b) CPU untranslated address > > It's neither. > > It's a cookie that you can do arithmetic off and pass on to the > readx/writex, and nothing more. You cannot make any assumptions at all > about what it means. > > In particular, you can _not_ assume that it is a PCI bus address ("WHICH > bus?") and you can absolutely not assume that it is a CPU address (many > CPU's do not "memory map" PCI at all). In which case, can we change the following in IO-mapping.txt please? /* * remap framebuffer PCI memory area at 0xFC000000, * size 1MB, so that we can access it: We can directly * access only the 640k-1MB area, so anything else * has to be remapped. */ char * baseptr = ioremap(0xFC000000, 1024*1024); since its not true? (since 0xfc000000 is a cookie). -- Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux http://www.arm.linux.org.uk/personal/aboutme.html