From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753216AbZAUUGn (ORCPT ); Wed, 21 Jan 2009 15:06:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751414AbZAUUGd (ORCPT ); Wed, 21 Jan 2009 15:06:33 -0500 Received: from www.tglx.de ([62.245.132.106]:53569 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751319AbZAUUGd (ORCPT ); Wed, 21 Jan 2009 15:06:33 -0500 Date: Wed, 21 Jan 2009 21:06:12 +0100 From: "Hans J. Koch" To: Brandon Philips Cc: "Hans J. Koch" , Greg KH , linux-kernel@vger.kernel.org Subject: Re: uio: add the uio_aec driver Message-ID: <20090121200612.GA9626@local> References: <20090120204729.GA26477@jenkins.ifup.org> <20090120214832.GE3027@local> <20090121170116.GA18567@jenkins.ifup.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090121170116.GA18567@jenkins.ifup.org> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 21, 2009 at 09:01:16AM -0800, Brandon Philips wrote: > > The portio feature is available since .29-rc1, please use it. > > Sounds good. I will rework it along with your suggestions below. Fine. I had a look at their homepage, seems to be interesting hardware. > > > > uioport is designed to be a setuid program and checks the permissions of > > > the /dev/uio* node and if the user has write permissions it will use > > > iopl and out*/in* to access the device. > > > > What happens with PCI on PowerPC ? > > I don't know. I could use /dev/port but my concern is that the device > spec sheet specifies that some writes should be done with outb and > others with outl. /dev/port only uses outb. Do you know if outl is > different than four outb's to a device? It is very probably different (4 WR pulses instead of one), the question is if that causes different hardware behaviour. If there's a spec for it, then you should definitly obey it. What I had in mind was that those ioport regions cannot be mmapped on x86, but it's possible on ppc, AFAIK. Furthermore, you need to think about correct endianness handling. Thanks, Hans