1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright(c) 2022 Intel Corporation. All rights reserved. */ 3 #include <linux/debugfs.h> 4 #include <linux/device.h> 5 #include <linux/module.h> 6 #include <linux/pci.h> 7 8 #include "cxlmem.h" 9 #include "cxlpci.h" 10 11 /** 12 * DOC: cxl mem 13 * 14 * CXL memory endpoint devices and switches are CXL capable devices that are 15 * participating in CXL.mem protocol. Their functionality builds on top of the 16 * CXL.io protocol that allows enumerating and configuring components via 17 * standard PCI mechanisms. 18 * 19 * The cxl_mem driver owns kicking off the enumeration of this CXL.mem 20 * capability. With the detection of a CXL capable endpoint, the driver will 21 * walk up to find the platform specific port it is connected to, and determine 22 * if there are intervening switches in the path. If there are switches, a 23 * secondary action is to enumerate those (implemented in cxl_core). Finally the 24 * cxl_mem driver adds the device it is bound to as a CXL endpoint-port for use 25 * in higher level operations. 26 */ 27 28 static void enable_suspend(void *data) 29 { 30 cxl_mem_active_dec(); 31 } 32 33 static void remove_debugfs(void *dentry) 34 { 35 debugfs_remove_recursive(dentry); 36 } 37 38 static int cxl_mem_dpa_show(struct seq_file *file, void *data) 39 { 40 struct device *dev = file->private; 41 struct cxl_memdev *cxlmd = to_cxl_memdev(dev); 42 43 cxl_dpa_debug(file, cxlmd->cxlds); 44 45 return 0; 46 } 47 48 static int devm_cxl_add_endpoint(struct device *host, struct cxl_memdev *cxlmd, 49 struct cxl_dport *parent_dport) 50 { 51 struct cxl_port *parent_port = parent_dport->port; 52 struct cxl_port *endpoint, *iter, *down; 53 int rc; 54 55 /* 56 * Now that the path to the root is established record all the 57 * intervening ports in the chain. 58 */ 59 for (iter = parent_port, down = NULL; !is_cxl_root(iter); 60 down = iter, iter = to_cxl_port(iter->dev.parent)) { 61 struct cxl_ep *ep; 62 63 ep = cxl_ep_load(iter, cxlmd); 64 ep->next = down; 65 } 66 67 /* Note: endpoint port component registers are derived from @cxlds */ 68 endpoint = devm_cxl_add_port(host, &cxlmd->dev, CXL_RESOURCE_NONE, 69 parent_dport); 70 if (IS_ERR(endpoint)) 71 return PTR_ERR(endpoint); 72 73 rc = cxl_endpoint_autoremove(cxlmd, endpoint); 74 if (rc) 75 return rc; 76 77 if (!endpoint->dev.driver) { 78 dev_err(&cxlmd->dev, "%s failed probe\n", 79 dev_name(&endpoint->dev)); 80 return -ENXIO; 81 } 82 83 return 0; 84 } 85 86 static int cxl_debugfs_poison_inject(void *data, u64 dpa) 87 { 88 struct cxl_memdev *cxlmd = data; 89 90 return cxl_inject_poison(cxlmd, dpa); 91 } 92 93 DEFINE_DEBUGFS_ATTRIBUTE(cxl_poison_inject_fops, NULL, 94 cxl_debugfs_poison_inject, "%llx\n"); 95 96 static int cxl_debugfs_poison_clear(void *data, u64 dpa) 97 { 98 struct cxl_memdev *cxlmd = data; 99 100 return cxl_clear_poison(cxlmd, dpa); 101 } 102 103 DEFINE_DEBUGFS_ATTRIBUTE(cxl_poison_clear_fops, NULL, 104 cxl_debugfs_poison_clear, "%llx\n"); 105 106 static int cxl_mem_probe(struct device *dev) 107 { 108 struct cxl_memdev *cxlmd = to_cxl_memdev(dev); 109 struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds); 110 struct cxl_dev_state *cxlds = cxlmd->cxlds; 111 struct device *endpoint_parent; 112 struct cxl_port *parent_port; 113 struct cxl_dport *dport; 114 struct dentry *dentry; 115 int rc; 116 117 if (!cxlds->media_ready) 118 return -EBUSY; 119 120 /* 121 * Someone is trying to reattach this device after it lost its port 122 * connection (an endpoint port previously registered by this memdev was 123 * disabled). This racy check is ok because if the port is still gone, 124 * no harm done, and if the port hierarchy comes back it will re-trigger 125 * this probe. Port rescan and memdev detach work share the same 126 * single-threaded workqueue. 127 */ 128 if (work_pending(&cxlmd->detach_work)) 129 return -EBUSY; 130 131 dentry = cxl_debugfs_create_dir(dev_name(dev)); 132 debugfs_create_devm_seqfile(dev, "dpamem", dentry, cxl_mem_dpa_show); 133 134 if (test_bit(CXL_POISON_ENABLED_INJECT, mds->poison.enabled_cmds)) 135 debugfs_create_file("inject_poison", 0200, dentry, cxlmd, 136 &cxl_poison_inject_fops); 137 if (test_bit(CXL_POISON_ENABLED_CLEAR, mds->poison.enabled_cmds)) 138 debugfs_create_file("clear_poison", 0200, dentry, cxlmd, 139 &cxl_poison_clear_fops); 140 141 rc = devm_add_action_or_reset(dev, remove_debugfs, dentry); 142 if (rc) 143 return rc; 144 145 rc = devm_cxl_enumerate_ports(cxlmd); 146 if (rc) 147 return rc; 148 149 parent_port = cxl_mem_find_port(cxlmd, &dport); 150 if (!parent_port) { 151 dev_err(dev, "CXL port topology not found\n"); 152 return -ENXIO; 153 } 154 155 if (dport->rch) 156 endpoint_parent = parent_port->uport_dev; 157 else 158 endpoint_parent = &parent_port->dev; 159 160 cxl_setup_parent_dport(dev, dport); 161 162 device_lock(endpoint_parent); 163 if (!endpoint_parent->driver) { 164 dev_err(dev, "CXL port topology %s not enabled\n", 165 dev_name(endpoint_parent)); 166 rc = -ENXIO; 167 goto unlock; 168 } 169 170 rc = devm_cxl_add_endpoint(endpoint_parent, cxlmd, dport); 171 unlock: 172 device_unlock(endpoint_parent); 173 put_device(&parent_port->dev); 174 if (rc) 175 return rc; 176 177 if (resource_size(&cxlds->pmem_res) && IS_ENABLED(CONFIG_CXL_PMEM)) { 178 rc = devm_cxl_add_nvdimm(cxlmd); 179 if (rc == -ENODEV) 180 dev_info(dev, "PMEM disabled by platform\n"); 181 else 182 return rc; 183 } 184 185 /* 186 * The kernel may be operating out of CXL memory on this device, 187 * there is no spec defined way to determine whether this device 188 * preserves contents over suspend, and there is no simple way 189 * to arrange for the suspend image to avoid CXL memory which 190 * would setup a circular dependency between PCI resume and save 191 * state restoration. 192 * 193 * TODO: support suspend when all the regions this device is 194 * hosting are locked and covered by the system address map, 195 * i.e. platform firmware owns restoring the HDM configuration 196 * that it locked. 197 */ 198 cxl_mem_active_inc(); 199 return devm_add_action_or_reset(dev, enable_suspend, NULL); 200 } 201 202 static ssize_t trigger_poison_list_store(struct device *dev, 203 struct device_attribute *attr, 204 const char *buf, size_t len) 205 { 206 bool trigger; 207 int rc; 208 209 if (kstrtobool(buf, &trigger) || !trigger) 210 return -EINVAL; 211 212 rc = cxl_trigger_poison_list(to_cxl_memdev(dev)); 213 214 return rc ? rc : len; 215 } 216 static DEVICE_ATTR_WO(trigger_poison_list); 217 218 static umode_t cxl_mem_visible(struct kobject *kobj, struct attribute *a, int n) 219 { 220 if (a == &dev_attr_trigger_poison_list.attr) { 221 struct device *dev = kobj_to_dev(kobj); 222 struct cxl_memdev *cxlmd = to_cxl_memdev(dev); 223 struct cxl_memdev_state *mds = 224 to_cxl_memdev_state(cxlmd->cxlds); 225 226 if (!test_bit(CXL_POISON_ENABLED_LIST, 227 mds->poison.enabled_cmds)) 228 return 0; 229 } 230 return a->mode; 231 } 232 233 static struct attribute *cxl_mem_attrs[] = { 234 &dev_attr_trigger_poison_list.attr, 235 NULL 236 }; 237 238 static struct attribute_group cxl_mem_group = { 239 .attrs = cxl_mem_attrs, 240 .is_visible = cxl_mem_visible, 241 }; 242 243 __ATTRIBUTE_GROUPS(cxl_mem); 244 245 static struct cxl_driver cxl_mem_driver = { 246 .name = "cxl_mem", 247 .probe = cxl_mem_probe, 248 .id = CXL_DEVICE_MEMORY_EXPANDER, 249 .drv = { 250 .dev_groups = cxl_mem_groups, 251 }, 252 }; 253 254 module_cxl_driver(cxl_mem_driver); 255 256 MODULE_LICENSE("GPL v2"); 257 MODULE_IMPORT_NS(CXL); 258 MODULE_ALIAS_CXL(CXL_DEVICE_MEMORY_EXPANDER); 259 /* 260 * create_endpoint() wants to validate port driver attach immediately after 261 * endpoint registration. 262 */ 263 MODULE_SOFTDEP("pre: cxl_port"); 264