From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935925AbcKWLVs (ORCPT ); Wed, 23 Nov 2016 06:21:48 -0500 Received: from mail-lf0-f45.google.com ([209.85.215.45]:36581 "EHLO mail-lf0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933826AbcKWLVH (ORCPT ); Wed, 23 Nov 2016 06:21:07 -0500 Subject: Re: [PATCH V9 11/11] ARM64/PCI: Support for ACPI based PCI host controller To: Bjorn Helgaas References: <1465588519-11334-1-git-send-email-tn@semihalf.com> <1465588519-11334-12-git-send-email-tn@semihalf.com> <20161122231321.GA20246@bhelgaas-glaptop.roam.corp.google.com> Cc: arnd@arndb.de, will.deacon@arm.com, catalin.marinas@arm.com, rafael@kernel.org, hanjun.guo@linaro.org, Lorenzo.Pieralisi@arm.com, okaya@codeaurora.org, jchandra@broadcom.com, robert.richter@caviumnetworks.com, mw@semihalf.com, Liviu.Dudau@arm.com, ddaney@caviumnetworks.com, wangyijing@huawei.com, Suravee.Suthikulpanit@amd.com, msalter@redhat.com, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linaro-acpi@lists.linaro.org, jcm@redhat.com, andrea.gallo@linaro.org, dhdang@apm.com, jeremy.linton@arm.com, liudongdong3@huawei.com, cov@codeaurora.org From: Tomasz Nowicki Message-ID: Date: Wed, 23 Nov 2016 12:21:03 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Firefox/45.0 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <20161122231321.GA20246@bhelgaas-glaptop.roam.corp.google.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Bjorn, On 23.11.2016 00:13, Bjorn Helgaas wrote: > Hi Tomasz, > > On Fri, Jun 10, 2016 at 09:55:19PM +0200, Tomasz Nowicki wrote: >> Implement pci_acpi_scan_root and other arch-specific call so that ARM64 >> can start using ACPI to setup and enumerate PCI buses. >> >> Prior to buses enumeration the pci_acpi_scan_root() implementation looks >> for configuration space start address (obtained through ACPI _CBA method or >> MCFG interface). If succeed, it uses ECAM library to create new mapping. >> Then it attaches generic ECAM ops (pci_generic_ecam_ops) which are used >> for accessing configuration space later on. >> ... > >> +static struct acpi_pci_root_ops acpi_pci_root_ops = { >> + .release_info = pci_acpi_generic_release_info, >> +}; >> + >> +/* Interface called from ACPI code to setup PCI host controller */ >> struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) >> { >> - /* TODO: Should be revisited when implementing PCI on ACPI */ >> - return NULL; >> + int node = acpi_get_node(root->device->handle); >> + struct acpi_pci_generic_root_info *ri; >> + struct pci_bus *bus, *child; >> + >> + ri = kzalloc_node(sizeof(*ri), GFP_KERNEL, node); >> + if (!ri) >> + return NULL; >> + >> + ri->cfg = pci_acpi_setup_ecam_mapping(root); >> + if (!ri->cfg) { >> + kfree(ri); >> + return NULL; >> + } >> + >> + acpi_pci_root_ops.pci_ops = &ri->cfg->ops->pci_ops; > > This has already been merged, but this isn't right, is it? We're > writing a host controller-specific pointer into the single system-wide > acpi_pci_root_ops, then passing it on to acpi_pci_root_create(). > > Today, I think ri->cfg->ops->pci_ops is always &pci_generic_ecam_ops, > from this path: > > ri->cfg = pci_acpi_setup_ecam_mapping > cfg = pci_ecam_create(..., &pci_generic_ecam_ops) > cfg = kzalloc(...) > cfg->ops = ops # &pci_generic_ecam_ops > > But we're about to merge the ECAM quirks series, which will mean it > may not be &pci_generic_ecam_ops. Even apart from the ECAM quirks, we > should avoid this pattern of putting device-specific info in a single > shared structure because it's too difficult to verify that it's > correct. > Well spotted. I agree, we need to fix this. How about this: diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c index fb439c7..31c0e1c 100644 --- a/arch/arm64/kernel/pci.c +++ b/arch/arm64/kernel/pci.c @@ -152,33 +152,35 @@ static void pci_acpi_generic_release_info(struct acpi_pci_root_info *ci) ri = container_of(ci, struct acpi_pci_generic_root_info, common); pci_ecam_free(ri->cfg); + kfree(ci->ops); kfree(ri); } -static struct acpi_pci_root_ops acpi_pci_root_ops = { - .release_info = pci_acpi_generic_release_info, -}; - /* Interface called from ACPI code to setup PCI host controller */ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) { int node = acpi_get_node(root->device->handle); struct acpi_pci_generic_root_info *ri; struct pci_bus *bus, *child; + struct acpi_pci_root_ops *root_ops; ri = kzalloc_node(sizeof(*ri), GFP_KERNEL, node); if (!ri) return NULL; + root_ops = kzalloc_node(sizeof(*root_ops), GFP_KERNEL, node); + if (!root_ops) + return NULL; + ri->cfg = pci_acpi_setup_ecam_mapping(root); if (!ri->cfg) { kfree(ri); + kfree(root_ops); return NULL; } - acpi_pci_root_ops.pci_ops = &ri->cfg->ops->pci_ops; - bus = acpi_pci_root_create(root, &acpi_pci_root_ops, &ri->common, - ri->cfg); + root_ops->release_info = pci_acpi_generic_release_info; + root_ops->pci_ops = &ri->cfg->ops->pci_ops; + bus = acpi_pci_root_create(root, root_ops, &ri->common, ri->cfg); if (!bus) return NULL; Of course, this should be the part of ECAM quirks core patches. The other option we have is to remove "struct pci_ops *pci_ops;" from acpi_pci_root_ops structure and pass struct pci_ops as an extra argument to acpi_pci_root_create(). What do you think? Thanks, Tomasz