From patchwork Wed May 12 14:37:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dongdong Liu X-Patchwork-Id: 12253963 X-Patchwork-Delegate: bhelgaas@google.com 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 F2C4CC433B4 for ; Wed, 12 May 2021 14:38:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C3D5861407 for ; Wed, 12 May 2021 14:38:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231352AbhELOjL (ORCPT ); Wed, 12 May 2021 10:39:11 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:3736 "EHLO szxga04-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230398AbhELOjK (ORCPT ); Wed, 12 May 2021 10:39:10 -0400 Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4FgHP83hMMzqTY6; Wed, 12 May 2021 22:34:36 +0800 (CST) Received: from SZX1000464847.huawei.com (10.21.59.169) by DGGEMS406-HUB.china.huawei.com (10.3.19.206) with Microsoft SMTP Server id 14.3.498.0; Wed, 12 May 2021 22:37:56 +0800 From: Dongdong Liu To: , , , , CC: , Subject: [PATCH V3 6/6] PCI: Enable 10-Bit tag support for PCIe RP devices Date: Wed, 12 May 2021 22:37:37 +0800 Message-ID: <20210512143737.42352-7-liudongdong3@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210512143737.42352-1-liudongdong3@huawei.com> References: <20210512143737.42352-1-liudongdong3@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.21.59.169] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org PCIe spec 5.0r1.0 section 2.2.6.2 implementation note, In configurations where a Requester with 10-Bit Tag Requester capability needs to target multiple Completers, one needs to ensure that the Requester sends 10-Bit Tag Requests only to Completers that have 10-Bit Tag Completer capability. So we enable 10-Bit Tag Requester for root port only when the devices under the root port support 10-Bit Tag Completer. Signed-off-by: Dongdong Liu --- drivers/pci/pcie/portdrv_pci.c | 75 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c index c7ff1ee..baf413f 100644 --- a/drivers/pci/pcie/portdrv_pci.c +++ b/drivers/pci/pcie/portdrv_pci.c @@ -90,6 +90,78 @@ static const struct dev_pm_ops pcie_portdrv_pm_ops = { #define PCIE_PORTDRV_PM_OPS NULL #endif /* !PM */ +static int pci_10bit_tag_comp_support(struct pci_dev *dev, void *data) +{ + u8 *support = data; + + if (*support == 0) + return 0; + + if (!pci_is_pcie(dev)) { + *support = 0; + return 0; + } + + /* + * PCIe spec 5.0r1.0 section 2.2.6.2 implementation note. + * For configurations where a Requester with 10-Bit Tag Requester + * capability targets Completers where some do and some do not have + * 10-Bit Tag Completer capability, how the Requester determines which + * NPRs include 10-Bit Tags is outside the scope of this specification. + * So we do not consider hotplug scenario. + */ + if (dev->is_hotplug_bridge) { + *support = 0; + return 0; + } + + if (!(dev->pcie_devcap2 & PCI_EXP_DEVCAP2_10BIT_TAG_COMP)) { + *support = 0; + return 0; + } + + return 0; +} + +static void pci_configure_rp_10bit_tag(struct pci_dev *dev) +{ + u8 support = 1; + struct pci_dev *pchild; + + if (dev->subordinate == NULL) + return; + + /* If no devices under the root port, no need to enable 10-Bit Tag. */ + pchild = list_first_entry_or_null(&dev->subordinate->devices, + struct pci_dev, bus_list); + if (pchild == NULL) + return; + + pci_10bit_tag_comp_support(dev, &support); + if (!support) + return; + + /* + * PCIe spec 5.0r1.0 section 2.2.6.2 implementation note. + * In configurations where a Requester with 10-Bit Tag Requester + * capability needs to target multiple Completers, one needs to ensure + * that the Requester sends 10-Bit Tag Requests only to Completers + * that have 10-Bit Tag Completer capability. So we enable 10-Bit Tag + * Requester for root port only when the devices under the root port + * support 10-Bit Tag Completer. + */ + pci_walk_bus(dev->subordinate, pci_10bit_tag_comp_support, &support); + if (!support) + return; + + if (!(dev->pcie_devcap2 & PCI_EXP_DEVCAP2_10BIT_TAG_REQ)) + return; + + pci_dbg(dev, "enabling 10-Bit Tag Requester\n"); + pcie_capability_set_word(dev, PCI_EXP_DEVCTL2, + PCI_EXP_DEVCTL2_10BIT_TAG_REQ_EN); +} + /* * pcie_portdrv_probe - Probe PCI-Express port devices * @dev: PCI-Express port device being probed @@ -111,6 +183,9 @@ static int pcie_portdrv_probe(struct pci_dev *dev, (type != PCI_EXP_TYPE_RC_EC))) return -ENODEV; + if (type == PCI_EXP_TYPE_ROOT_PORT) + pci_configure_rp_10bit_tag(dev); + if (type == PCI_EXP_TYPE_RC_EC) pcie_link_rcec(dev);