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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 DDDA5C54FD0 for ; Mon, 27 Apr 2020 15:45:55 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5834B20661 for ; Mon, 27 Apr 2020 15:45:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5834B20661 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 499pyl5dSRzDqcN for ; Tue, 28 Apr 2020 01:45:51 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=linux.intel.com (client-ip=192.55.52.88; helo=mga01.intel.com; envelope-from=sathyanarayanan.kuppuswamy@linux.intel.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.intel.com Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 499pvd4C1PzDqYV for ; Tue, 28 Apr 2020 01:43:08 +1000 (AEST) IronPort-SDR: ualyudOXaQB0vSfoRxNU7auk4BX/3HXh4sH7mSOydcPT4V+/lDDfTFXSTwWQTIC/97DePbCZTJ FfCbMlhjNKDA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Apr 2020 08:43:04 -0700 IronPort-SDR: xzyccRZCToBiEJJk7VKV/GPt/PAPE3bvggxB4tPyWAm6ywDykKrxSp9+ORjMHYMItH+bBWnPKY gPL7deJG9Vfw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,324,1583222400"; d="scan'208";a="336331704" Received: from djmuller-mobl.amr.corp.intel.com (HELO [10.255.231.74]) ([10.255.231.74]) by orsmga001.jf.intel.com with ESMTP; 27 Apr 2020 08:43:04 -0700 Subject: Re: [PATCH v2 2/2] PCI/DPC: Allow Native DPC Host Bridges to use DPC To: "Derrick, Jonathan" , "helgaas@kernel.org" References: <1587418630-13562-1-git-send-email-jonathan.derrick@intel.com> <1587418630-13562-3-git-send-email-jonathan.derrick@intel.com> <0058b993-0663-7fed-ed31-cb0adf845a39@linux.intel.com> <7e574cc1-a24b-5c4b-7d4f-3fda3f395390@linux.intel.com> <6344a9afcc585504c5dfbc00174280613683064d.camel@intel.com> From: "Kuppuswamy, Sathyanarayanan" Message-ID: <6ee30f16-0a91-04cd-c8ba-72d177fab8f4@linux.intel.com> Date: Mon, 27 Apr 2020 08:43:03 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <6344a9afcc585504c5dfbc00174280613683064d.camel@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "bhelgaas@google.com" , "Patel, Mayurkumar" , "fred@fredlawl.com" , "sbobroff@linux.ibm.com" , "linuxppc-dev@lists.ozlabs.org" , "Wysocki, Rafael J" , "linux-pci@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "andriy.shevchenko@linux.intel.com" , "olof@lixom.net" , "alex.williamson@redhat.com" , "oohall@gmail.com" , "kbusch@kernel.org" , "rajatja@google.com" , "mika.westerberg@linux.intel.com" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 4/27/20 8:15 AM, Derrick, Jonathan wrote: > Hi Sathyanarayanan, > > On Sat, 2020-04-25 at 13:46 -0700, Kuppuswamy, Sathyanarayanan wrote: >> >> On 4/23/20 8:11 AM, Derrick, Jonathan wrote: >>> Hi Sathyanarayanan, >>> >>> On Wed, 2020-04-22 at 15:50 -0700, Kuppuswamy, Sathyanarayanan wrote: >>>> On 4/20/20 2:37 PM, Jon Derrick wrote: >>>>> The existing portdrv model prevents DPC services without either OS >>>>> control (_OSC) granted to AER services, a Host Bridge requesting Native >>>>> AER, or using one of the 'pcie_ports=' parameters of 'native' or >>>>> 'dpc-native'. >>>>> >>>>> The DPC port service driver itself will also fail to probe if the kernel >>>>> assumes the port is using Firmware-First AER. It's a reasonable >>>>> expectation that a port using Firmware-First AER will also be using >>>>> Firmware-First DPC, however if a Host Bridge requests Native DPC, the >>>>> DPC driver should allow it and not fail to bind due to AER capability >>>>> settings. >>>>> >>>>> Host Bridges which request Native DPC port services will also likely >>>>> request Native AER, however it shouldn't be a requirement. This patch >>>>> allows ports on those Host Bridges to have DPC port services. >>>>> >>>>> This will avoid the unlikely situation where the port is Firmware-First >>>>> AER and Native DPC, and a BIOS or switch firmware preconfiguration of >>>>> the DPC trigger could result in unhandled DPC events. >>>>> >>>>> Signed-off-by: Jon Derrick >>>>> --- >>>>> drivers/pci/pcie/dpc.c | 3 ++- >>>>> drivers/pci/pcie/portdrv_core.c | 3 ++- >>>>> 2 files changed, 4 insertions(+), 2 deletions(-) >>>>> >>>>> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c >>>>> index 7621704..3f3106f 100644 >>>>> --- a/drivers/pci/pcie/dpc.c >>>>> +++ b/drivers/pci/pcie/dpc.c >>>>> @@ -284,7 +284,8 @@ static int dpc_probe(struct pcie_device *dev) >>>>> int status; >>>>> u16 ctl, cap; >>>>> >>>>> - if (pcie_aer_get_firmware_first(pdev) && !pcie_ports_dpc_native) >>>>> + if (pcie_aer_get_firmware_first(pdev) && !pcie_ports_dpc_native && >>>>> + !pci_find_host_bridge(pdev->bus)->native_dpc) >>>> Why do it in probe as well ? if host->native_dpc is not set then the >>>> device DPC probe it self won't happen right ? >>> >>> Portdrv only enables the interrupt and allows the probe to occur. >> >> Please check the following snippet of code (from portdrv_core.c). >> >> IIUC, pcie_device_init() will not be called if PCIE_PORT_SERVICE_DPC is >> not set in capabilities. Your change in portdrv_core.c already >> selectively enables the PCIE_PORT_SERVICE_DPC service based on >> native_dpc value. >> > That's right. So pcie_device_init registers the port service driver > allowing the services enumeration to occur. > >> So IMO, adding native_dpc check in dpc_probe() is redundant. >> >> int pcie_port_device_register(struct pci_dev *dev) >> /* Allocate child services if any */ >> status = -ENODEV; >> nr_service = 0; >> for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++) { >> int service = 1 << i; >> if (!(capabilities & service)) >> continue; >> if (!pcie_device_init(dev, service, irqs[i])) >> nr_service++; >> } >> > This is the tricky part > There's still a check in dpc_probe for AER FFS or pcie_ports=dpc- > native: > > if (pcie_aer_get_firmware_first(pdev) && !pcie_ports_dpc_native) > return -ENOTSUPP; > > One option is to move that to get_port_device_capability and remove the > dpc_probe check Yes, its better to group them together in get_port_device_capability(). But it should be done in a separate patch. > >>> The probe itself will still fail if there's a mixed-mode _OSC >>> negotiated AER & DPC, due to pcie_aer_get_firmware_first returning 1 >>> for AER and no check for DPC. >>> >>> I don't know if such a platform will exist, but the kernel is already >>> wired for 'dpc-native' so it makes sense to extend it for this.. >>> >>> This transform might be more readable: >>> if (pcie_aer_get_firmware_first(pdev) && >>> !(pcie_ports_dpc_native || hb->native_dpc)) >>> >>> >>> >>>>> return -ENOTSUPP; >>>>> >>>>> status = devm_request_threaded_irq(device, dev->irq, dpc_irq, >>>>> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c >>>>> index 50a9522..f2139a1 100644 >>>>> --- a/drivers/pci/pcie/portdrv_core.c >>>>> +++ b/drivers/pci/pcie/portdrv_core.c >>>>> @@ -256,7 +256,8 @@ static int get_port_device_capability(struct pci_dev *dev) >>>>> */ >>>>> if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) && >>>>> pci_aer_available() && >>>>> - (pcie_ports_dpc_native || (services & PCIE_PORT_SERVICE_AER))) >>>>> + (pcie_ports_dpc_native || host->native_dpc || >>>>> + (services & PCIE_PORT_SERVICE_AER))) >>>>> services |= PCIE_PORT_SERVICE_DPC; >>>>> >>>>> if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM || >>>>>