Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755532AbcDGIjP (ORCPT ); Thu, 7 Apr 2016 04:39:15 -0400 Received: from mx0b-0016f401.pphosted.com ([67.231.156.173]:20727 "EHLO mx0b-0016f401.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755194AbcDGIjL (ORCPT ); Thu, 7 Apr 2016 04:39:11 -0400 Date: Thu, 7 Apr 2016 16:34:43 +0800 From: Jisheng Zhang To: Gabriele Paoloni CC: "jingoohan1@gmail.com" , "pratyush.anand@gmail.com" , "bhelgaas@google.com" , "linux-pci@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH v2] PCI: designware: move remaining rc setup code to dw_pcie_setup_rc() Message-ID: <20160407163443.291fbd49@xhacker> In-Reply-To: References: <1458128433-3020-1-git-send-email-jszhang@marvell.com> <20160407103734.55e72da7@xhacker> X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-04-07_07:,, signatures=0 X-Proofpoint-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1601100000 definitions=main-1604070127 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3017 Lines: 86 Hi Gabriele, On Thu, 7 Apr 2016 08:20:28 +0000 Gabriele Paoloni wrote: > Hi Jisheng > > Thanks for your reply > > > -----Original Message----- > > From: Jisheng Zhang [mailto:jszhang@marvell.com] > > Sent: 07 April 2016 03:38 > > To: Gabriele Paoloni; jingoohan1@gmail.com; pratyush.anand@gmail.com; > > bhelgaas@google.com > > Cc: linux-pci@vger.kernel.org; linux-kernel@vger.kernel.org; linux-arm- > > kernel@lists.infradead.org > > Subject: Re: [PATCH v2] PCI: designware: move remaining rc setup code > > to dw_pcie_setup_rc() > > > > Hi Gabriele, > > > > On Wed, 6 Apr 2016 14:50:29 +0000 Gabriele Paoloni wrote: > > > > > Hi, sorry to be late on this > > > > > > > -----Original Message----- > > > > From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel- > > > > owner@vger.kernel.org] On Behalf Of Jisheng Zhang > > > > Sent: 16 March 2016 11:41 > > > > To: jingoohan1@gmail.com; pratyush.anand@gmail.com; > > bhelgaas@google.com > > > > Cc: linux-pci@vger.kernel.org; linux-kernel@vger.kernel.org; linux- > > arm- > > > > kernel@lists.infradead.org; Jisheng Zhang > > > > Subject: [PATCH v2] PCI: designware: move remaining rc setup code > > to > > > > dw_pcie_setup_rc() > > > > > > > > dw_pcie_setup_rc(), as its name indicates, setups the RC. But > > current > > > > dw_pcie_host_init() also contains some necessary rc setup code. > > > > > > > > Another reason: the host may lost power during suspend to ram, the > > RC > > > > need to be re-setup after resume. The rc can't be correctly resumed > > > > without the rc setup code in dw_pcie_host_init(). > > > > > > > > So this patch moves the code to dw_pcie_setup_rc() to address the > > above > > > > two issues. After this patch, each pcie designware driver users > > could > > > > call dw_pcie_setup_rc() to re-setup rc when resume back. > > > > > > I think this patch breaks the Hisilicon driver... > > > > > > Our driver performs linkup setup in UEFI therefore we do not call > > > dw_pcie_setup_rc(), we only call dw_pcie_host_init(). > > > > Thanks for the information. So pcie-hisi rely on UEFI to do something > > similar > > in dw_pcie_setup_rc(), this comes to a common driver implement > > question: should > > linux device driver rely on bootloader to configure HW device? > > I don't see any issue with this... > > > > > Is it acceptable that pcie-hisi adds a call to dw_pcie_setup_rc() in > > hisi_add_pcie_port()? > > I don't think so...that would try to overwrite what is already set by > the bootloader; so it is wrong in principle and maybe it can lead to > undefined behaviours... make sense! This commit is intend to re-setup the rc when waken from s2ram (in s2ram state, the host lost power) I have no good solution but to introduce one function e.g dw_pcie_setup_rc_after_linkup(), then move related code from dw_pcie_host_init to it, then let my host driver resume hook to call. Hi Pratyush, Jingoo and Bjorn etc. any suggestions are appreciated! Thanks, Jisheng