From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A439BC43143 for ; Mon, 1 Oct 2018 14:36:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 75998208AE for ; Mon, 1 Oct 2018 14:36:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 75998208AE Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-pci-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729452AbeJAVOG (ORCPT ); Mon, 1 Oct 2018 17:14:06 -0400 Received: from foss.arm.com ([217.140.101.70]:50636 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729378AbeJAVOF (ORCPT ); Mon, 1 Oct 2018 17:14:05 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id BBE6C18A; Mon, 1 Oct 2018 07:35:58 -0700 (PDT) Received: from red-moon (red-moon.emea.arm.com [10.4.13.120]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0138E3F5B3; Mon, 1 Oct 2018 07:35:55 -0700 (PDT) Date: Mon, 1 Oct 2018 15:36:41 +0100 From: Lorenzo Pieralisi To: honghui.zhang@mediatek.com Cc: bhelgaas@google.com, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, ryder.lee@mediatek.com, ulf.hansson@linaro.org, marc.zyngier@arm.com, matthias.bgg@gmail.com, devicetree@vger.kernel.org, yingjoe.chen@mediatek.com, eddie.huang@mediatek.com, youlin.pei@mediatek.com, yt.shen@mediatek.com, sean.wang@mediatek.com Subject: Re: [PATCH v5 1/9] PCI: mediatek: Using slot's devfn for compare to fix mtk_pcie_find_port logic Message-ID: <20181001143641.GB13049@red-moon> References: <1538129080-8206-1-git-send-email-honghui.zhang@mediatek.com> <1538129080-8206-2-git-send-email-honghui.zhang@mediatek.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1538129080-8206-2-git-send-email-honghui.zhang@mediatek.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Fri, Sep 28, 2018 at 06:04:32PM +0800, honghui.zhang@mediatek.com wrote: > From: Honghui Zhang > > The Mediatek's host controller has two slots, each with it's own control > registers. The host driver need to identify which slot was connected > in order to access the device's configuration space. There's problem > for current host driver to find out which slot was connected to for > a given EP device. > > Assuming each slot have connect with one EP device as below: > > host bridge > bus 0 --> __________|_______ > | | > | | > slot 0 slot 1 > bus 1 -->| bus 2 --> | > | | > EP 0 EP 1 > > During PCI enumeration, system software will scan all the PCI device > starting from devfn 0. So it will get the proper port for slot0 and > slot1 device when using PCI_SLOT(devfn) for match. But it will get > the wrong slot for EP1: The devfn will be start from 0 when scanning > EP1 behind slot1, it will get port0 since the PCI_SLOT(EP1) is match > for port0's slot value. So the host driver should not using EP's devfn > but the slot's devfn(the slot which EP was connected to) for match. > > This patch fix the mtk_pcie_find_port's logic by using the slot's > devfn for match if finding device connected to the subordinate bus. > > Signed-off-by: Honghui Zhang > --- > drivers/pci/controller/pcie-mediatek.c | 17 ++++++++++++++++- > 1 file changed, 16 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c > index 9999dae..264e03f 100644 > --- a/drivers/pci/controller/pcie-mediatek.c > +++ b/drivers/pci/controller/pcie-mediatek.c > @@ -337,10 +337,25 @@ static struct mtk_pcie_port *mtk_pcie_find_port(struct pci_bus *bus, > { > struct mtk_pcie *pcie = bus->sysdata; > struct mtk_pcie_port *port; > + struct pci_dev *dev = NULL; > + > + /* > + * Walk the bus hierarchy to get the devfn value > + * of the port in the root bus. > + */ > + while (bus && bus->number) { > + dev = bus->self; > + bus = dev->bus; If you add: devfn = dev->devfn; here > + } > + > + list_for_each_entry(port, &pcie->ports, list) { > + /* Using slot's devfn to compare for subordinary bus. */ > + if (dev) > + devfn = dev->devfn; You can remove this ugly hunk altogether (and dev initialization to NULL). Lorenzo > - list_for_each_entry(port, &pcie->ports, list) > if (port->slot == PCI_SLOT(devfn)) > return port; > + } > > return NULL; > } > -- > 2.6.4 >