Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932489AbbFLIFB (ORCPT ); Fri, 12 Jun 2015 04:05:01 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:58599 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752695AbbFLIEw (ORCPT ); Fri, 12 Jun 2015 04:04:52 -0400 Message-ID: <557A9292.30901@roeck-us.net> Date: Fri, 12 Jun 2015 01:04:34 -0700 From: Guenter Roeck User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Lorenzo Pieralisi , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org CC: Ralf Baechle , "James E.J. Bottomley" , Michael Ellerman , Bjorn Helgaas , Richard Henderson , Benjamin Herrenschmidt , David Howells , Russell King , Tony Luck , "David S. Miller" , Ingo Molnar , Michal Simek , Chris Zankel , Arnd Bergmann , Krzysztof Halasa , Phil Edworthy , Jason Gunthorpe , Jingoo Han , Lucas Stach , Simon Horman , Minghuan Lian , Murali Karicheri , Tanmay Inamdar , Kishon Vijay Abraham I , Thierry Reding , Thomas Petazzoni , Will Deacon , Jayachandran C , Suravee Suthikulpanit Subject: Re: [RFC/RFT PATCH v2] PCI: move pci_read_bridge_bases to the generic PCI layer References: <1433840506-20083-1-git-send-email-lorenzo.pieralisi@arm.com> In-Reply-To: <1433840506-20083-1-git-send-email-lorenzo.pieralisi@arm.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated_sender: linux@roeck-us.net X-OutGoing-Spam-Status: No, score=0.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: linux@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2444 Lines: 55 On 06/09/2015 02:01 AM, Lorenzo Pieralisi wrote: > When a PCI bus is scanned, upon PCI bridge detection the kernel > has to read the bridge registers to set-up its resources so that > the PCI resource hierarchy can be validated properly. > > Most if not all architectures read PCI bridge registers in the > pcibios_fixup_bus hook, that is called by the PCI generic layer > whenever a PCI bus is scanned. > > Since pci_read_bridge_bases is an arch agnostic operation (and it > is carried out on all architectures) it can be moved to the generic > PCI layer in order to consolidate code and remove the respective > calls from the architectures back-ends. > > The PCI_PROBE_ONLY flag is not checked before calling > pci_read_bridge_buses in the generic layer since reading the bridge > bases is not related to resources assignment; this implies that it > can be carried out safely on PCI_PROBE_ONLY systems too and should > not affect architectures (alpha, mips) that check the PCI_PROBE_ONLY > flag before reading the bridge bases. > > In order to validate the resource hierarchy as soon as the resources > themselves are probed (ie read from the bridge), this patch also adds > code to pci_read_bridge_bases that claims the bridge resources, so that > they are validated and inserted in the resource hierarchy as soon as > the bridge bases are probed. > > Signed-off-by: Lorenzo Pieralisi > Cc: Ralf Baechle > Cc: James E.J. Bottomley > Cc: Michael Ellerman > Cc: Bjorn Helgaas > Cc: Richard Henderson > Cc: Benjamin Herrenschmidt > Cc: David Howells > Cc: Russell King > Cc: Tony Luck > Cc: David S. Miller > Cc: Ingo Molnar > Cc: Guenter Roeck > Cc: Michal Simek > Cc: Chris Zankel Working fine on powerpc (tested with Freescale P2020 and P5020) as well as x86 (tested on two different server class systems). Tested-by: Guenter Roeck Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/