From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: 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 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> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: youlin.pei@mediatek.com, devicetree , hongkun.cao@mediatek.com, Lorenzo Pieralisi , Marc Zyngier , linux-pci@vger.kernel.org, sean.wang@mediatek.com, Linux Kernel Mailing List , YT Shen , Matthias Brugger , ryder.lee@mediatek.com, "moderated list:ARM/Mediatek SoC support" , yong.wu@mediatek.com, Bjorn Helgaas , yingjoe.chen@mediatek.com, Eddie Huang , linux-arm Mailing List Content-Type: text/plain; charset="us-ascii" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+bjorn=helgaas.com@lists.infradead.org List-ID: 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 > > > > > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel