1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright(c) 2022 Intel Corporation. All rights reserved. */ 3 #include <linux/device.h> 4 #include <linux/module.h> 5 #include <linux/slab.h> 6 7 #include "cxlmem.h" 8 #include "cxlpci.h" 9 10 /** 11 * DOC: cxl port 12 * 13 * The port driver enumerates dport via PCI and scans for HDM 14 * (Host-managed-Device-Memory) decoder resources via the 15 * @component_reg_phys value passed in by the agent that registered the 16 * port. All descendant ports of a CXL root port (described by platform 17 * firmware) are managed in this drivers context. Each driver instance 18 * is responsible for tearing down the driver context of immediate 19 * descendant ports. The locking for this is validated by 20 * CONFIG_PROVE_CXL_LOCKING. 21 * 22 * The primary service this driver provides is presenting APIs to other 23 * drivers to utilize the decoders, and indicating to userspace (via bind 24 * status) the connectivity of the CXL.mem protocol throughout the 25 * PCIe topology. 26 */ 27 28 static void schedule_detach(void *cxlmd) 29 { 30 schedule_cxl_memdev_detach(cxlmd); 31 } 32 33 static int cxl_port_probe(struct device *dev) 34 { 35 struct cxl_port *port = to_cxl_port(dev); 36 struct cxl_hdm *cxlhdm; 37 int rc; 38 39 if (is_cxl_endpoint(port)) { 40 struct cxl_memdev *cxlmd = to_cxl_memdev(port->uport); 41 42 get_device(&cxlmd->dev); 43 rc = devm_add_action_or_reset(dev, schedule_detach, cxlmd); 44 if (rc) 45 return rc; 46 } else { 47 rc = devm_cxl_port_enumerate_dports(port); 48 if (rc < 0) 49 return rc; 50 if (rc == 1) 51 return devm_cxl_add_passthrough_decoder(port); 52 } 53 54 cxlhdm = devm_cxl_setup_hdm(port); 55 if (IS_ERR(cxlhdm)) 56 return PTR_ERR(cxlhdm); 57 58 rc = devm_cxl_enumerate_decoders(cxlhdm); 59 if (rc) { 60 dev_err(dev, "Couldn't enumerate decoders (%d)\n", rc); 61 return rc; 62 } 63 64 return 0; 65 } 66 67 static struct cxl_driver cxl_port_driver = { 68 .name = "cxl_port", 69 .probe = cxl_port_probe, 70 .id = CXL_DEVICE_PORT, 71 }; 72 73 module_cxl_driver(cxl_port_driver); 74 MODULE_LICENSE("GPL v2"); 75 MODULE_IMPORT_NS(CXL); 76 MODULE_ALIAS_CXL(CXL_DEVICE_PORT); 77