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 discover_region(struct device *dev, void *root) 34 { 35 struct cxl_endpoint_decoder *cxled; 36 int rc; 37 38 if (!is_endpoint_decoder(dev)) 39 return 0; 40 41 cxled = to_cxl_endpoint_decoder(dev); 42 if ((cxled->cxld.flags & CXL_DECODER_F_ENABLE) == 0) 43 return 0; 44 45 if (cxled->state != CXL_DECODER_STATE_AUTO) 46 return 0; 47 48 /* 49 * Region enumeration is opportunistic, if this add-event fails, 50 * continue to the next endpoint decoder. 51 */ 52 rc = cxl_add_to_region(root, cxled); 53 if (rc) 54 dev_dbg(dev, "failed to add to region: %#llx-%#llx\n", 55 cxled->cxld.hpa_range.start, cxled->cxld.hpa_range.end); 56 57 return 0; 58 } 59 60 static int cxl_switch_port_probe(struct cxl_port *port) 61 { 62 struct cxl_hdm *cxlhdm; 63 int rc; 64 65 /* Cache the data early to ensure is_visible() works */ 66 read_cdat_data(port); 67 68 rc = devm_cxl_port_enumerate_dports(port); 69 if (rc < 0) 70 return rc; 71 72 cxlhdm = devm_cxl_setup_hdm(port, NULL); 73 if (!IS_ERR(cxlhdm)) 74 return devm_cxl_enumerate_decoders(cxlhdm, NULL); 75 76 if (PTR_ERR(cxlhdm) != -ENODEV) { 77 dev_err(&port->dev, "Failed to map HDM decoder capability\n"); 78 return PTR_ERR(cxlhdm); 79 } 80 81 if (rc == 1) { 82 dev_dbg(&port->dev, "Fallback to passthrough decoder\n"); 83 return devm_cxl_add_passthrough_decoder(port); 84 } 85 86 dev_err(&port->dev, "HDM decoder capability not found\n"); 87 return -ENXIO; 88 } 89 90 static int cxl_endpoint_port_probe(struct cxl_port *port) 91 { 92 struct cxl_endpoint_dvsec_info info = { .port = port }; 93 struct cxl_memdev *cxlmd = to_cxl_memdev(port->uport_dev); 94 struct cxl_dev_state *cxlds = cxlmd->cxlds; 95 struct cxl_hdm *cxlhdm; 96 struct cxl_port *root; 97 int rc; 98 99 rc = cxl_dvsec_rr_decode(cxlds->dev, cxlds->cxl_dvsec, &info); 100 if (rc < 0) 101 return rc; 102 103 cxlhdm = devm_cxl_setup_hdm(port, &info); 104 if (IS_ERR(cxlhdm)) { 105 if (PTR_ERR(cxlhdm) == -ENODEV) 106 dev_err(&port->dev, "HDM decoder registers not found\n"); 107 return PTR_ERR(cxlhdm); 108 } 109 110 /* Cache the data early to ensure is_visible() works */ 111 read_cdat_data(port); 112 113 get_device(&cxlmd->dev); 114 rc = devm_add_action_or_reset(&port->dev, schedule_detach, cxlmd); 115 if (rc) 116 return rc; 117 118 rc = cxl_hdm_decode_init(cxlds, cxlhdm, &info); 119 if (rc) 120 return rc; 121 122 rc = devm_cxl_enumerate_decoders(cxlhdm, &info); 123 if (rc) 124 return rc; 125 126 /* 127 * This can't fail in practice as CXL root exit unregisters all 128 * descendant ports and that in turn synchronizes with cxl_port_probe() 129 */ 130 root = find_cxl_root(port); 131 132 /* 133 * Now that all endpoint decoders are successfully enumerated, try to 134 * assemble regions from committed decoders 135 */ 136 device_for_each_child(&port->dev, root, discover_region); 137 put_device(&root->dev); 138 139 return 0; 140 } 141 142 static int cxl_port_probe(struct device *dev) 143 { 144 struct cxl_port *port = to_cxl_port(dev); 145 146 if (is_cxl_endpoint(port)) 147 return cxl_endpoint_port_probe(port); 148 return cxl_switch_port_probe(port); 149 } 150 151 static ssize_t CDAT_read(struct file *filp, struct kobject *kobj, 152 struct bin_attribute *bin_attr, char *buf, 153 loff_t offset, size_t count) 154 { 155 struct device *dev = kobj_to_dev(kobj); 156 struct cxl_port *port = to_cxl_port(dev); 157 158 if (!port->cdat_available) 159 return -ENXIO; 160 161 if (!port->cdat.table) 162 return 0; 163 164 return memory_read_from_buffer(buf, count, &offset, 165 port->cdat.table, 166 port->cdat.length); 167 } 168 169 static BIN_ATTR_ADMIN_RO(CDAT, 0); 170 171 static umode_t cxl_port_bin_attr_is_visible(struct kobject *kobj, 172 struct bin_attribute *attr, int i) 173 { 174 struct device *dev = kobj_to_dev(kobj); 175 struct cxl_port *port = to_cxl_port(dev); 176 177 if ((attr == &bin_attr_CDAT) && port->cdat_available) 178 return attr->attr.mode; 179 180 return 0; 181 } 182 183 static struct bin_attribute *cxl_cdat_bin_attributes[] = { 184 &bin_attr_CDAT, 185 NULL, 186 }; 187 188 static struct attribute_group cxl_cdat_attribute_group = { 189 .bin_attrs = cxl_cdat_bin_attributes, 190 .is_bin_visible = cxl_port_bin_attr_is_visible, 191 }; 192 193 static const struct attribute_group *cxl_port_attribute_groups[] = { 194 &cxl_cdat_attribute_group, 195 NULL, 196 }; 197 198 static struct cxl_driver cxl_port_driver = { 199 .name = "cxl_port", 200 .probe = cxl_port_probe, 201 .id = CXL_DEVICE_PORT, 202 .drv = { 203 .dev_groups = cxl_port_attribute_groups, 204 }, 205 }; 206 207 module_cxl_driver(cxl_port_driver); 208 MODULE_LICENSE("GPL v2"); 209 MODULE_IMPORT_NS(CXL); 210 MODULE_ALIAS_CXL(CXL_DEVICE_PORT); 211