From patchwork Sun Jun 6 06:05:22 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 12301833 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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 AECDFC4743E for ; Sun, 6 Jun 2021 06:05:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9CB28613F3 for ; Sun, 6 Jun 2021 06:05:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230130AbhFFGHO (ORCPT ); Sun, 6 Jun 2021 02:07:14 -0400 Received: from mga09.intel.com ([134.134.136.24]:65367 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230075AbhFFGHO (ORCPT ); Sun, 6 Jun 2021 02:07:14 -0400 IronPort-SDR: 7QXAiA/y2Gu2FRYJ+f/08tMELvkVbr4tXKEPPAq37xrszi9CrwSBVe3g1d9HhCXhSWFAZDFyUl BhwJ5fxFSl3g== X-IronPort-AV: E=McAfee;i="6200,9189,10006"; a="204456559" X-IronPort-AV: E=Sophos;i="5.83,252,1616482800"; d="scan'208";a="204456559" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jun 2021 23:05:25 -0700 IronPort-SDR: mXD91DzjKjQEQ4MU7FJI54jX2AM6QlqHjU7xbHiNCC9EXZsTMPnBKPYi701JWPWVka2tqW+y6l WMsqyuwWp42g== X-IronPort-AV: E=Sophos;i="5.83,252,1616482800"; d="scan'208";a="447133004" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.25]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jun 2021 23:05:22 -0700 Subject: [PATCH v5 5/6] cxl/acpi: Enumerate host bridge root ports From: Dan Williams To: linux-cxl@vger.kernel.org Cc: linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org Date: Sat, 05 Jun 2021 23:05:22 -0700 Message-ID: <162295952254.1109360.12071591891784594995.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <162295949351.1109360.10329014558746500142.stgit@dwillia2-desk3.amr.corp.intel.com> References: <162295949351.1109360.10329014558746500142.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-3-g996c MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org While the resources enumerated by the CEDT.CFMWS identify a cxl_port with host bridges as downstream ports, host bridges themselves are upstream ports that decode to downstream ports represented by PCIe Root Ports. Walk the PCIe Root Ports connected to a CXL Host Bridge, identified by the ACPI0016 _HID, and add each one as a cxl_dport of the host bridge cxl_port. For now, component registers are not enumerated, only the first order uport / dport relationships. Signed-off-by: Dan Williams Reviewed-by: Jonathan Cameron --- drivers/cxl/acpi.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 95 insertions(+), 2 deletions(-) diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c index 0ae7464b603d..ec324bf063b8 100644 --- a/drivers/cxl/acpi.c +++ b/drivers/cxl/acpi.c @@ -8,6 +8,48 @@ #include #include "cxl.h" +struct cxl_walk_context { + struct device *dev; + struct pci_bus *root; + struct cxl_port *port; + int error; + int count; +}; + +static int match_add_root_ports(struct pci_dev *pdev, void *data) +{ + struct cxl_walk_context *ctx = data; + struct pci_bus *root_bus = ctx->root; + struct cxl_port *port = ctx->port; + int type = pci_pcie_type(pdev); + struct device *dev = ctx->dev; + u32 lnkcap, port_num; + int rc; + + if (pdev->bus != root_bus) + return 0; + if (!pci_is_pcie(pdev)) + return 0; + if (type != PCI_EXP_TYPE_ROOT_PORT) + return 0; + if (pci_read_config_dword(pdev, pci_pcie_cap(pdev) + PCI_EXP_LNKCAP, + &lnkcap) != PCIBIOS_SUCCESSFUL) + return 0; + + /* TODO walk DVSEC to find component register base */ + port_num = FIELD_GET(PCI_EXP_LNKCAP_PN, lnkcap); + rc = cxl_add_dport(port, &pdev->dev, port_num, CXL_RESOURCE_NONE); + if (rc) { + ctx->error = rc; + return rc; + } + ctx->count++; + + dev_dbg(dev, "add dport%d: %s\n", port_num, dev_name(&pdev->dev)); + + return 0; +} + static struct acpi_device *to_cxl_host_bridge(struct device *dev) { struct acpi_device *adev = to_acpi_device(dev); @@ -17,6 +59,44 @@ static struct acpi_device *to_cxl_host_bridge(struct device *dev) return NULL; } +/* + * A host bridge is a dport to a CFMWS decode and it is a uport to the + * dport (PCIe Root Ports) in the host bridge. + */ +static int add_host_bridge_uport(struct device *match, void *arg) +{ + struct acpi_device *bridge = to_cxl_host_bridge(match); + struct cxl_port *root_port = arg; + struct device *host = root_port->dev.parent; + struct acpi_pci_root *pci_root; + struct cxl_walk_context ctx; + struct cxl_port *port; + + if (!bridge) + return 0; + + pci_root = acpi_pci_find_root(bridge->handle); + if (!pci_root) + return -ENXIO; + + /* TODO: fold in CEDT.CHBS retrieval */ + port = devm_cxl_add_port(host, match, CXL_RESOURCE_NONE, root_port); + if (IS_ERR(port)) + return PTR_ERR(port); + dev_dbg(host, "%s: add: %s\n", dev_name(match), dev_name(&port->dev)); + + ctx = (struct cxl_walk_context){ + .dev = host, + .root = pci_root->bus, + .port = port, + }; + pci_walk_bus(pci_root->bus, match_add_root_ports, &ctx); + + if (ctx.count == 0) + return -ENODEV; + return ctx.error; +} + static int add_host_bridge_dport(struct device *match, void *arg) { int rc; @@ -49,6 +129,7 @@ static int add_host_bridge_dport(struct device *match, void *arg) static int cxl_acpi_probe(struct platform_device *pdev) { + int rc; struct cxl_port *root_port; struct device *host = &pdev->dev; struct acpi_device *adev = ACPI_COMPANION(host); @@ -58,8 +139,20 @@ static int cxl_acpi_probe(struct platform_device *pdev) return PTR_ERR(root_port); dev_dbg(host, "add: %s\n", dev_name(&root_port->dev)); - return bus_for_each_dev(adev->dev.bus, NULL, root_port, - add_host_bridge_dport); + rc = bus_for_each_dev(adev->dev.bus, NULL, root_port, + add_host_bridge_dport); + if (rc) + return rc; + + /* + * Root level scanned with host-bridge as dports, now scan host-bridges + * for their role as CXL uports to their CXL-capable PCIe Root Ports. + */ + rc = bus_for_each_dev(adev->dev.bus, NULL, root_port, + add_host_bridge_uport); + if (rc) + dev_err(host, "failed to scan host bridges\n"); + return 0; } static const struct acpi_device_id cxl_acpi_ids[] = {