// SPDX-License-Identifier: GPL-2.0-only /* Copyright(c) 2022 Intel Corporation. All rights reserved. */ #include <linux/device.h> #include <linux/module.h> #include <linux/slab.h> #include "cxlmem.h" #include "cxlpci.h" /** * DOC: cxl port * * The port driver enumerates dport via PCI and scans for HDM * (Host-managed-Device-Memory) decoder resources via the * @component_reg_phys value passed in by the agent that registered the * port. All descendant ports of a CXL root port (described by platform * firmware) are managed in this drivers context. Each driver instance * is responsible for tearing down the driver context of immediate * descendant ports. The locking for this is validated by * CONFIG_PROVE_CXL_LOCKING. * * The primary service this driver provides is presenting APIs to other * drivers to utilize the decoders, and indicating to userspace (via bind * status) the connectivity of the CXL.mem protocol throughout the * PCIe topology. */ static void schedule_detach(void *cxlmd) { schedule_cxl_memdev_detach(cxlmd); } static int cxl_port_probe(struct device *dev) { struct cxl_port *port = to_cxl_port(dev); struct cxl_hdm *cxlhdm; int rc; if (!is_cxl_endpoint(port)) { rc = devm_cxl_port_enumerate_dports(port); if (rc < 0) return rc; if (rc == 1) return devm_cxl_add_passthrough_decoder(port); } cxlhdm = devm_cxl_setup_hdm(port); if (IS_ERR(cxlhdm)) return PTR_ERR(cxlhdm); if (is_cxl_endpoint(port)) { struct cxl_memdev *cxlmd = to_cxl_memdev(port->uport); struct cxl_dev_state *cxlds = cxlmd->cxlds; /* Cache the data early to ensure is_visible() works */ read_cdat_data(port); get_device(&cxlmd->dev); rc = devm_add_action_or_reset(dev, schedule_detach, cxlmd); if (rc) return rc; rc = cxl_hdm_decode_init(cxlds, cxlhdm); if (rc) return rc; rc = cxl_await_media_ready(cxlds); if (rc) { dev_err(dev, "Media not active (%d)\n", rc); return rc; } } rc = devm_cxl_enumerate_decoders(cxlhdm); if (rc) { dev_err(dev, "Couldn't enumerate decoders (%d)\n", rc); return rc; } return 0; } static ssize_t CDAT_read(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t offset, size_t count) { struct device *dev = kobj_to_dev(kobj); struct cxl_port *port = to_cxl_port(dev); if (!port->cdat_available) return -ENXIO; if (!port->cdat.table) return 0; return memory_read_from_buffer(buf, count, &offset, port->cdat.table, port->cdat.length); } static BIN_ATTR_ADMIN_RO(CDAT, 0); static umode_t cxl_port_bin_attr_is_visible(struct kobject *kobj, struct bin_attribute *attr, int i) { struct device *dev = kobj_to_dev(kobj); struct cxl_port *port = to_cxl_port(dev); if ((attr == &bin_attr_CDAT) && port->cdat_available) return attr->attr.mode; return 0; } static struct bin_attribute *cxl_cdat_bin_attributes[] = { &bin_attr_CDAT, NULL, }; static struct attribute_group cxl_cdat_attribute_group = { .bin_attrs = cxl_cdat_bin_attributes, .is_bin_visible = cxl_port_bin_attr_is_visible, }; static const struct attribute_group *cxl_port_attribute_groups[] = { &cxl_cdat_attribute_group, NULL, }; static struct cxl_driver cxl_port_driver = { .name = "cxl_port", .probe = cxl_port_probe, .id = CXL_DEVICE_PORT, .drv = { .dev_groups = cxl_port_attribute_groups, }, }; module_cxl_driver(cxl_port_driver); MODULE_LICENSE("GPL v2"); MODULE_IMPORT_NS(CXL); MODULE_ALIAS_CXL(CXL_DEVICE_PORT);