From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:26335 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S268282AbUIPWap (ORCPT ); Thu, 16 Sep 2004 18:30:45 -0400 Date: Thu, 16 Sep 2004 23:30:42 +0100 From: Matthew Wilcox Subject: Re: RFC: being more anal about iospace accesses.. Message-ID: <20040916223042.GO642@parcelfarce.linux.theplanet.co.uk> References: <1095287935.1688.4.camel@mulgrave> <20040916023325.GJ642@parcelfarce.linux.theplanet.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: To: Linus Torvalds Cc: Matthew Wilcox , James Bottomley , Geert Uytterhoeven , Linux Arch list , Al Viro , Andrew Morton , Alan Cox , "David S. Miller" , Jeff Garzik List-ID: On Wed, Sep 15, 2004 at 09:28:01PM -0700, Linus Torvalds wrote: > Indeed. Once created, the cookie is "bus-agnostic", which is very much the > point. Unlike the original pci DMA interfaces, there are no real bus > assumtions in the interfaces once set up. In designing the new iomap interface for PA, I noticed a problem. 2004/09/14 torvalds | * They do _not_ update the port address. If you 2004/09/14 torvalds | * want MMIO that copies stuff laid out in MMIO 2004/09/14 torvalds | * memory across multiple ports, use "memcpy_toio()" 2004/09/14 torvalds | * and friends. That implies you can pass an iomap cookie to memcpy_toio(), which makes designing the iomap interface significantly harder. Could I ask for iocopy_to(), iocopy_from() and ioset() interfaces too? -- "Next the statesmen will invent cheap lies, putting the blame upon the nation that is attacked, and every man will be glad of those conscience-soothing falsities, and will diligently study them, and refuse to examine any refutations of them; and thus he will by and by convince himself that the war is just, and will thank God for the better sleep he enjoys after this process of grotesque self-deception." -- Mark Twain