Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Received-SPF: Pass (protection.outlook.com: domain of amd.com designates
 165.204.84.17 as permitted sender) receiver=protection.outlook.com;
 client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; pr=C
From:   Robert Richter <rrichter@amd.com>
To:     Alison Schofield <alison.schofield@intel.com>,
        Vishal Verma <vishal.l.verma@intel.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Ben Widawsky <bwidawsk@kernel.org>,
        Dan Williams <dan.j.williams@intel.com>
CC:     <linux-cxl@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Len Brown <lenb@kernel.org>, Robert Richter <rrichter@amd.com>
Subject: [PATCH 08/15] cxl/acpi: Check RCH's CXL DVSEC capabilities
Date:   Wed, 31 Aug 2022 10:15:56 +0200
Message-ID: <20220831081603.3415-9-rrichter@amd.com>
In-Reply-To: <20220831081603.3415-1-rrichter@amd.com>
References: <20220831081603.3415-1-rrichter@amd.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 31 Aug 2022 08:17:00.4959
 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: f7b1bb8d-d717-4eed-8d69-08da8b292deb
X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com]
X-MS-Exchange-CrossTenant-AuthSource: CO1NAM11FT051.eop-nam11.prod.protection.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Anonymous
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL1PR12MB5350
X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,
        RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,SPF_PASS,T_SCC_BODY_TEXT_LINE
        autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

An RCH has an RCiEP connected to it with CXL DVSEC capabilities
present and the CXL PCIe DVSEC included. Check this.

Signed-off-by: Robert Richter <rrichter@amd.com>
---
 drivers/cxl/acpi.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index ffdf439adb87..f9cdf23a91a8 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -322,6 +322,8 @@ struct pci_host_bridge *cxl_find_next_rch(struct pci_host_bridge *host)
 {
 	struct pci_bus *bus = host ? host->bus : NULL;
 	struct acpi_device *adev;
+	struct pci_dev *pdev;
+	bool is_restricted_host;
 
 	while ((bus = pci_find_next_bus(bus)) != NULL) {
 		host = bus ? to_pci_host_bridge(bus->bridge) : NULL;
@@ -343,6 +345,20 @@ struct pci_host_bridge *cxl_find_next_rch(struct pci_host_bridge *host)
 		dev_dbg(&host->dev, "PCI ACPI host found: %s\n",
 			acpi_dev_name(adev));
 
+		/* Check CXL DVSEC of dev 0 func 0 */
+		pdev = pci_get_slot(bus, PCI_DEVFN(0, 0));
+		is_restricted_host = pdev
+			&& (pci_pcie_type(pdev) == PCI_EXP_TYPE_RC_END)
+			&& pci_find_dvsec_capability(pdev,
+						PCI_DVSEC_VENDOR_ID_CXL,
+						CXL_DVSEC_PCIE_DEVICE);
+		pci_dev_put(pdev);
+
+		if (!is_restricted_host)
+			continue;
+
+		dev_dbg(&host->dev, "CXL restricted host found\n");
+
 		return host;
 	}
 
@@ -354,6 +370,7 @@ static int __init cxl_restricted_host_probe(struct platform_device *pdev)
 	struct pci_host_bridge *host = NULL;
 
 	while ((host = cxl_find_next_rch(host)) != NULL) {
+		dev_info(&host->dev, "host supports CXL\n");
 	}
 
 	return 0;
-- 
2.30.2