From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Nowicki Subject: Re: [RFC PATCH 1/3] pci, acpi: Match PCI config space accessors against platfrom specific ECAM quirks. Date: Thu, 2 Jun 2016 15:35:34 +0200 Message-ID: <57503626.9050208@semihalf.com> References: <1464856864-18049-1-git-send-email-tn@semihalf.com> <4347711.qDrKz2s8lr@wuerfel> <5750218F.9030406@semihalf.com> <9294389.sZPDtyjoUs@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-lf0-f44.google.com ([209.85.215.44]:32995 "EHLO mail-lf0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751650AbcFBNfk (ORCPT ); Thu, 2 Jun 2016 09:35:40 -0400 Received: by mail-lf0-f44.google.com with SMTP id s64so34181832lfe.0 for ; Thu, 02 Jun 2016 06:35:39 -0700 (PDT) In-Reply-To: <9294389.sZPDtyjoUs@wuerfel> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Arnd Bergmann , linux-arm-kernel@lists.infradead.org Cc: rafael@kernel.org, linux-pci@vger.kernel.org, will.deacon@arm.com, okaya@codeaurora.org, wangyijing@huawei.com, andrea.gallo@linaro.org, Lorenzo.Pieralisi@arm.com, linaro-acpi@lists.linaro.org, ddaney@caviumnetworks.com, linux-acpi@vger.kernel.org, robert.richter@caviumnetworks.com, helgaas@kernel.org, liudongdong3@huawei.com, catalin.marinas@arm.com, Liviu.Dudau@arm.com, jcm@redhat.com, msalter@redhat.com, cov@codeaurora.org, mw@semihalf.com, jchandra@broadcom.com, dhdang@apm.com, linux-kernel@vger.kernel.org, jeremy.linton@arm.com, hanjun.guo@linaro.org, Suravee.Suthikulpanit@amd.com On 02.06.2016 14:32, Arnd Bergmann wrote: > On Thursday, June 2, 2016 2:07:43 PM CEST Tomasz Nowicki wrote: >> On 02.06.2016 13:42, Arnd Bergmann wrote: >>> On Thursday, June 2, 2016 10:41:01 AM CEST Tomasz Nowicki wrote: >>>> +struct pci_ecam_ops *pci_mcfg_get_ops(struct acpi_pci_root *root) >>>> +{ >>>> + int bus_num = root->secondary.start; >>>> + int domain = root->segment; >>>> + struct pci_cfg_fixup *f; >>>> + >>>> + if (!mcfg_table) >>>> + return &pci_generic_ecam_ops; >>>> + >>>> + /* >>>> + * Match against platform specific quirks and return corresponding >>>> + * CAM ops. >>>> + * >>>> + * First match against PCI topology then use OEM ID and >>>> + * OEM revision from MCFG table standard header. >>>> + */ >>>> + for (f = __start_acpi_mcfg_fixups; f < __end_acpi_mcfg_fixups; f++) { >>>> + if ((f->domain == domain || f->domain == PCI_MCFG_DOMAIN_ANY) && >>>> + (f->bus_num == bus_num || f->bus_num == PCI_MCFG_BUS_ANY) && >>>> + (!strncmp(f->oem_id, mcfg_table->header.oem_id, >>>> + ACPI_OEM_ID_SIZE)) && >>>> + (f->oem_revision == mcfg_table->header.oem_revision)) >>>> + return f->ops; >>>> + } >>>> + /* No quirks, use ECAM */ >>>> + return &pci_generic_ecam_ops; >>>> +} >>>> + >>>> int pci_mcfg_lookup(struct acpi_pci_root *root) >>> >>> Can you explain the use of pci_ecam_ops instead of pci_ops here? >>> >> >> I wanted to get associated bus_shift and use it to setup configuration >> region properly before calling pci_ecam_create. Please see next patch. >> > > I see. It feels really odd to do it this way though, since having a > nonstandard bus_shift essentially means not using anything resembling > ECAM to start with. > > I realize that a lot of the host bridges are not ECAM, but because > of this, it would be more logical to have their own pci_ops instead > of pci_ecam_ops. Well, we have bus_shift there to express bus shift differentiation. So I would say we should change just structure name to prevent misunderstanding. Thanks, Tomasz