Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265315AbTIDRZF (ORCPT ); Thu, 4 Sep 2003 13:25:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265316AbTIDRZF (ORCPT ); Thu, 4 Sep 2003 13:25:05 -0400 Received: from fw.osdl.org ([65.172.181.6]:36789 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S265315AbTIDRY7 (ORCPT ); Thu, 4 Sep 2003 13:24:59 -0400 Date: Thu, 4 Sep 2003 10:24:38 -0700 (PDT) From: Linus Torvalds To: Jeff Garzik cc: Geert Uytterhoeven , Paul Mackerras , Christoph Hellwig , "David S. Miller" , Linux Kernel Development Subject: Re: [PATCH] fix ppc ioremap prototype In-Reply-To: <3F5772B2.402@pobox.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1379 Lines: 34 On Thu, 4 Sep 2003, Jeff Garzik wrote: > > Would still be nice to have a sysdata or struct device pointer in struct > resource, then. I'm not a fan of wacky > bus-info-encoded-in-another-number schemes. But it _isn't_ "bus info". It's a unique number. It has no bus information embedded in it. It's a number that tells ioremap() what area to remap. It's a "hardware dependent iomem address". What the address _means_ is entirely up to the architecture, and depends on how devices are acccessed, and what is most convenient to make them accessible (with the first level of that access translation being done "statically" by ioremap(), and the second level of the access translation being done by "read[bwl]()" and friends). You could make "ioremap()" be a no-op and do all translation dynamically. Of you could make "ioremap()" be complex, and do no dynamic translation (x86). Or you can have a combination of the two. The numbers don't have "meaning" per se. The inputs to "ioremap()" are "ranges of something". They are the exact same "somethings" as lives in "iomem_resource" "resources of something". Linus - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/