From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964989AbcKXLKw (ORCPT ); Thu, 24 Nov 2016 06:10:52 -0500 Received: from mail-lf0-f42.google.com ([209.85.215.42]:35211 "EHLO mail-lf0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964890AbcKXLKt (ORCPT ); Thu, 24 Nov 2016 06:10:49 -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> <20161123182243.GF16033@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: Thu, 24 Nov 2016 12:10:44 +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: <20161123182243.GF16033@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 On 23.11.2016 19:22, Bjorn Helgaas wrote: > On Wed, Nov 23, 2016 at 12:21:03PM +0100, Tomasz Nowicki wrote: >> 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? > > I think your patch above is fine and avoids the need to change the x86 and > ia64 code. Would you mind packaging this up with a changelog and > signed-off-by? I can take care of putting it in the ECAM series. > Sure, I have just sent the patch in replay to ECAM quirks V6 patch set. Let us know when you update your branch so we base our quirks on it. Thanks, Tomasz