From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesse Barnes Subject: Re: iomapping a big endian area Date: Thu, 7 Apr 2005 16:57:53 -0700 Message-ID: <200504071657.54172.jbarnes@engr.sgi.com> References: <1112475134.5786.29.camel@mulgrave> <20050404141616.GA10384@infradead.org> <1112624705.5813.19.camel@mulgrave> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from omx2-ext.sgi.com ([192.48.171.19]:13540 "EHLO omx2.sgi.com") by vger.kernel.org with ESMTP id S262617AbVDHAAf (ORCPT ); Thu, 7 Apr 2005 20:00:35 -0400 In-Reply-To: <1112624705.5813.19.camel@mulgrave> Content-Disposition: inline Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: Christoph Hellwig , Benjamin Herrenschmidt , "David S. Miller" , matthew@wil.cx, SCSI Mailing List , Linux Kernel list On Monday, April 4, 2005 7:25 am, James Bottomley wrote: > On Mon, 2005-04-04 at 15:16 +0100, Christoph Hellwig wrote: > > The IOC4 device that provides IDE, serial ports and external interrupts > > on Altix systems has a big endian register layour, and the PCI-X bridge > > in those Altix systems can do the swapping if a special bit is set. > > > > In older kernels that bit was set from the driver through a special API, > > but it seems the firmware does that automatically now. > > We already have some unusual code in drivers to support other altix > design ... features ... do you regard this as something that's likely to > be replicated on other platforms, or is it more in the category of a one > off mistake that can be corrected in firmware? The whole line of altix pci bridges can do byteswapping, so it's more than just one product that could benefit (however slightly). Not sure about other bridges though. Jesse