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=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED 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 A1B5CC43144 for ; Thu, 28 Jun 2018 01:12:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F95625982 for ; Thu, 28 Jun 2018 01:12:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5F95625982 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=mediatek.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753022AbeF1BMP (ORCPT ); Wed, 27 Jun 2018 21:12:15 -0400 Received: from mailgw02.mediatek.com ([1.203.163.81]:54041 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751272AbeF1BMN (ORCPT ); Wed, 27 Jun 2018 21:12:13 -0400 X-UUID: 00570ab034cf4081a656ec8d55ad862b-20180628 Received: from mtkcas34.mediatek.inc [(172.27.4.250)] by mailgw02.mediatek.com (envelope-from ) (mailgw01.mediatek.com ESMTP with TLS) with ESMTP id 1573740479; Thu, 28 Jun 2018 09:12:09 +0800 Received: from MTKCAS36.mediatek.inc (172.27.4.186) by MTKMBS31N1.mediatek.inc (172.27.4.69) with Microsoft SMTP Server (TLS) id 15.0.1210.3; Thu, 28 Jun 2018 09:12:08 +0800 Received: from [10.17.3.153] (10.17.3.153) by MTKCAS36.mediatek.inc (172.27.4.170) with Microsoft SMTP Server id 15.0.1210.3 via Frontend Transport; Thu, 28 Jun 2018 09:12:07 +0800 Message-ID: <1530148327.28284.1.camel@mhfsdcap03> Subject: Re: [PATCH 1/4] PCI: mediatek: fixup mtk_pcie_find_port logical From: Honghui Zhang To: Andy Shevchenko CC: Lorenzo Pieralisi , Marc Zyngier , Bjorn Helgaas , "Matthias Brugger" , linux-arm Mailing List , "moderated list:ARM/Mediatek SoC support" , , Linux Kernel Mailing List , devicetree , , Eddie Huang , , , , , YT Shen , Date: Thu, 28 Jun 2018 09:12:07 +0800 In-Reply-To: References: <1530091298-28120-1-git-send-email-honghui.zhang@mediatek.com> <1530091298-28120-2-git-send-email-honghui.zhang@mediatek.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit MIME-Version: 1.0 X-MTK: N Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2018-06-27 at 19:35 +0300, Andy Shevchenko wrote: > On Wed, Jun 27, 2018 at 12:21 PM, wrote: > > From: Honghui Zhang > > > > Mediatek's host controller have two slots, each have 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 > > > > While PCI emulation, 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 logical by using the slot's > > devfn for match. > > > > + list_for_each_entry(port, &pcie->ports, list) { > > + if (bus->number == 0 && port->slot == PCI_SLOT(devfn)) { > > return port; > > + } else if (bus->number != 0) { > > You can do it like (no need 'else') > > if (...) > return ...; > if (bus->number) { > ... > } > > > + pbus = bus; > > + do { > > + dev = pbus->self; > > + if (port->slot == PCI_SLOT(dev->devfn)) > > + return port; > > + > > + pbus = dev->bus; > > + } while (dev->bus->number != 0); > > This can be rewritten like > > pbus = bus; > while (pbus->number) { > dev = ...; > ... > pbus = dev->bus; > } > > and no need for if (bus->number) anymore. > Hi, Andy, thanks very much for your advise, I will change it in the next version. thanks. > > + } > > + } > > > > return NULL; > > } > > -- > > 2.6.4 > > > > >