From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Subject: Re: [PATCHv2] PCI: QDF2432 32 bit config space accessors To: Bjorn Helgaas References: <20160921173129.GA20006@localhost> <20160921223805.21652-1-cov@codeaurora.org> <20161031214833.GB14603@bhelgaas-glaptop.roam.corp.google.com> <20161102160820.GA6568@bhelgaas-glaptop.roam.corp.google.com> <3fd26a0d-a5c2-c385-866e-b957dffb7dda@codeaurora.org> <20161103140058.GA31142@bhelgaas-glaptop.roam.corp.google.com> Cc: cov@codeaurora.org, Tomasz Nowicki , will.deacon@arm.com, catalin.marinas@arm.com, rafael@kernel.org, Lorenzo.Pieralisi@arm.com, arnd@arndb.de, hanjun.guo@linaro.org, jchandra@broadcom.com, dhdang@apm.com, ard.biesheuvel@linaro.org, robert.richter@caviumnetworks.com, mw@semihalf.com, Liviu.Dudau@arm.com, ddaney@caviumnetworks.com, wangyijing@huawei.com, msalter@redhat.com, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linaro-acpi@lists.linaro.org, jcm@redhat.com, andrea.gallo@linaro.org, jeremy.linton@arm.com, liudongdong3@huawei.com, gabriele.paoloni@huawei.com, jhugo@codeaurora.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org From: Sinan Kaya Message-ID: Date: Thu, 3 Nov 2016 13:06:28 -0400 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 List-ID: On 11/3/2016 12:58 PM, Sinan Kaya wrote: >> > This is the crucial point I have failed to communicate clearly: the >> > PNP0C02 resource is *always* required, even if the MCFG is correct. >> > > Interesting... > > It looks like there is a lot of lessons learnt here from history. > > I think this requirement is only true if your system DDR space and PCIe > space overlaps in the memory map. I understand that Intel systems allow > sharing of these two memory ranges. An OS could potentially reclaim this > address range. > > If there is no overlap and PCI is not enabled, there can't be any SW entity > to reclaim this space. > > Did I miss something? > For protection, it makes sense to reserve this range. I'm trying to understand who would claim this range. -- Sinan Kaya Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.