From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Nowicki Subject: Re: [Patch v7 4/7] PCI/ACPI: Add interface acpi_pci_root_create() Date: Fri, 27 Nov 2015 07:59:22 +0100 Message-ID: <5657FF4A.2080804@semihalf.com> References: <564185B6.8040006@linux.intel.com> <20151111174647.GA30051@red-moon> <56445117.8090307@linux.intel.com> <56449246.2010308@semihalf.com> <56449C55.2090001@linux.intel.com> <5644A613.2010304@semihalf.com> <5644AAB9.6010700@linux.intel.com> <5645DE3A.7040406@semihalf.com> <20151113170316.GB15253@red-moon> <56462294.3060701@linux.intel.com> <20151120101840.GD15819@red-moon> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-lf0-f47.google.com ([209.85.215.47]:34108 "EHLO mail-lf0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751544AbbK0HBJ (ORCPT ); Fri, 27 Nov 2015 02:01:09 -0500 Received: by lffu14 with SMTP id u14so119108237lff.1 for ; Thu, 26 Nov 2015 23:01:07 -0800 (PST) In-Reply-To: <20151120101840.GD15819@red-moon> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Jiang Liu Cc: Lorenzo Pieralisi , Arnd Bergmann , Bjorn Helgaas , "Rafael J . Wysocki" , Marc Zyngier , Hanjun Guo , Liviu Dudau , linux-acpi@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org On 20.11.2015 11:18, Lorenzo Pieralisi wrote: > Hi Jiang, > > On Sat, Nov 14, 2015 at 01:49:08AM +0800, Jiang Liu wrote: > > [...] > >>> Not really. My concern is that there might be platforms out there with >>> an offset between the CPU and PCI physical address spaces, and if we >>> remove the offset value in acpi_decode_space we can break them, >>> because in the kernel struct resource data we have to have CPU physical >>> addresses, not PCI ones. If offset == 0, we are home and dry, I do not >>> understand why that's a given, which is what we would assume if Jiang's >>> patch is merged as-is unless I am mistaken. >> We try to exclude offset from struct resource in generic ACPI code, >> and it's the arch's responsibility to decide how to manipulate struct >> resource object if offset is not zero. >> >> Currently offset is always zero for x86, and IA64 has arch specific >> code to handle non-zero offset. So we should be safe without breaking >> existing code. For ARM64, it's a little different from IA64 so it's >> hard to share code between IA64 and ARM64. > > Can you drop the patch on the mailing lists please, we actually need it > to get ACPI ARM64 PCIe support in the kernel, please let me know how > you want to handle this and if you need any help. > Kindly reminder. Regards, Tomasz