From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH 6/13] devres: implement managed iomap interface Date: Tue, 08 Apr 2008 18:55:13 +0400 Message-ID: <47FB8751.3040301@ru.mvista.com> References: <11684073371547-git-send-email-htejun@gmail.com> <47FA4FD2.8060808@ru.mvista.com> <47FB85CB.2070506@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from homer.mvista.com ([63.81.120.155]:41643 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752628AbYDHOzz (ORCPT ); Tue, 8 Apr 2008 10:55:55 -0400 In-Reply-To: <47FB85CB.2070506@gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: jgarzik@pobox.com, gregkh@suse.de, alan@lxorguk.ukuu.org.uk, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, linuxppc-dev@ozlabs.org Tejun Heo wrote: >> A very late comment but nevertheless... :-) > Better late than never. :-) >> Those functions are going to break on 32-bit platforms with >> extended physical address (well, that's starting with Pentiums which >> had 36-bit PAE :-) AND devices mapped beyond 4 GB (e.g. PowerPC 44x). >> You should have used resource_size_t for the 'offset' parameter. As >> this most probably means that libata is broken on such platforms, I'm >> going to submit a patch... It's broken with drivers using MMIO, I meant to say. > Yeah, right please go ahead. But I wonder whether any BIOS was actually > crazy enough to map mmio region above 4G on 32bit machine. This is a *hardware* mapping on some non-x86 platforms (like PPC 44x or MIPS Alchemy). The arch/ppc/ and arch/mips/ kernels have special hooks called from ioremap() which help create an illusion that the PCI memory space on such platforms (not only it) is mapped below 4 GB; arch/powerpc/ kernel doesn't do this anymore -- hence this newly encountered issue. WBR, Sergei