From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <54A6E0DE.6090309@amd.com> Date: Fri, 2 Jan 2015 12:18:06 -0600 From: Suravee Suthikulanit MIME-Version: 1.0 To: Lorenzo Pieralisi CC: Arnd Bergmann , Liviu Dudau , "linux-arm-kernel@lists.infradead.org" , Mark Rutland , "devicetree@vger.kernel.org" , "jason@lakedaemon.net" , "linux-doc@vger.kernel.org" , Marc Zyngier , "linux-pci@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Will Deacon , "robh+dt@kernel.org" , "Catalin Marinas" , "bhelgaas@google.com" , "tglx@linutronix.de" Subject: Re: [RFC 2/4] PCI: generic: Add support for ARM64 and MSI(x) References: <1411937610-22125-1-git-send-email-suravee.suthikulpanit@amd.com> <2148776.X8NPqiYA6S@wuerfel> <20141023091309.GF25302@e106497-lin.cambridge.arm.com> <2355100.WsW1DXh57P@wuerfel> <54A1AC5C.7000903@amd.com> <20150102115533.GA25573@red-moon> In-Reply-To: <20150102115533.GA25573@red-moon> Content-Type: text/plain; charset="windows-1252"; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: On 1/2/2015 5:55 AM, Lorenzo Pieralisi wrote: > Hi Suravee, > > On Mon, Dec 29, 2014 at 07:32:44PM +0000, Suravee Suthikulpanit wrote: >> >Hi, >> > >> >I am not sure if this thread is still alive. I'm trying to see what I >> >can do to help clean up/convert to make the PCI GHC also works for arm64 >> >w/ zero or minimal ifdefs. >> > >> >Please let me know if someone is already working on this. I noticed that >> >Lorenzo's patches has already been in 3.19-rc1, and in Bjorn's >> >pci/domain branch. Otherwise, I'll try to continue the work based on the >> >sample patch from Arnd here. > If I am not mistaken, the only bit missing to remove pci_sys_data (and so > having a generic host controller driver that works on ARM32/64) is generic > MSI management. Lorenzo, Do you mean to remove pci_sys_data from pci-host-generic.c or removing it completely? I assume the former case. So, looking at the current code in the pci-host-generic.c, my understanding is that the: *gen_pci = pci_bus->sysdata->private_data will be changed to: *gen_pci = pci_bus->sysdata Then, we can simply just call pci_scan_root_bus() directly since we no longer need to declare hw_pci for calling pci_common_init_dev(). > I know for certain Marc is working on it, and the solution is WIP, > I think we should prevent adding more churn to pci_sys_data, since > I managed to remove most of the dependencies (domain, mem_offset). Thanks for cleaning up the domain and mem_offset. I saw Marc's irq/msi_domain patch series (http://git.kernel.org/cgit/linux/kernel/git/maz/arm-platforms.git/log/?h=irq/msi_domain). My understanding is that deals with associating the newly introduced msi_domain to each device, which replaces the need for pci_bus->msi and hw_pci->msi_ctrl when configure with CONFIG_PCI_MSI_IRQ_DOMAIN (not sure if this would be the plan for all arm32). For ARM32, if not define CONFIG_PCI_MSI_IRQ_DOMAIN, it would still fall back to using the [pci_sys_data|hw_pci]->msi_ctrl. However, I noticed that the hw_pci->msi_controller is not even used for the pci-host-generic. So, this should not be blocking the work to free pci-host-generic from pci_sys_data and hw_pci, as the MSI stuff can go in separately. Am I missing something? > So to sum it up, to have a generic host controller driver for ARM32/64 > we just need to work out how to handle the MSI data, patches will be > on the lists shortly to handle that, please review. > > Thanks, > Lorenzo > Thanks for the update and the summary. I'll help review/test the MSI patch once posted. Thanks, Suravee