1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2006 Matthew Wilcox <matthew@wil.cx> 4 * Copyright (C) 2006-2009 Hewlett-Packard Development Company, L.P. 5 * Alex Chiang <achiang@hp.com> 6 */ 7 8 #include <linux/kobject.h> 9 #include <linux/slab.h> 10 #include <linux/module.h> 11 #include <linux/pci.h> 12 #include <linux/err.h> 13 #include "pci.h" 14 15 struct kset *pci_slots_kset; 16 EXPORT_SYMBOL_GPL(pci_slots_kset); 17 18 static ssize_t pci_slot_attr_show(struct kobject *kobj, 19 struct attribute *attr, char *buf) 20 { 21 struct pci_slot *slot = to_pci_slot(kobj); 22 struct pci_slot_attribute *attribute = to_pci_slot_attr(attr); 23 return attribute->show ? attribute->show(slot, buf) : -EIO; 24 } 25 26 static ssize_t pci_slot_attr_store(struct kobject *kobj, 27 struct attribute *attr, const char *buf, size_t len) 28 { 29 struct pci_slot *slot = to_pci_slot(kobj); 30 struct pci_slot_attribute *attribute = to_pci_slot_attr(attr); 31 return attribute->store ? attribute->store(slot, buf, len) : -EIO; 32 } 33 34 static const struct sysfs_ops pci_slot_sysfs_ops = { 35 .show = pci_slot_attr_show, 36 .store = pci_slot_attr_store, 37 }; 38 39 static ssize_t address_read_file(struct pci_slot *slot, char *buf) 40 { 41 if (slot->number == 0xff) 42 return sysfs_emit(buf, "%04x:%02x\n", 43 pci_domain_nr(slot->bus), 44 slot->bus->number); 45 46 return sysfs_emit(buf, "%04x:%02x:%02x\n", 47 pci_domain_nr(slot->bus), 48 slot->bus->number, 49 slot->number); 50 } 51 52 static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf) 53 { 54 return sysfs_emit(buf, "%s\n", pci_speed_string(speed)); 55 } 56 57 static ssize_t max_speed_read_file(struct pci_slot *slot, char *buf) 58 { 59 return bus_speed_read(slot->bus->max_bus_speed, buf); 60 } 61 62 static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf) 63 { 64 return bus_speed_read(slot->bus->cur_bus_speed, buf); 65 } 66 67 static void pci_slot_release(struct kobject *kobj) 68 { 69 struct pci_dev *dev; 70 struct pci_slot *slot = to_pci_slot(kobj); 71 72 dev_dbg(&slot->bus->dev, "dev %02x, released physical slot %s\n", 73 slot->number, pci_slot_name(slot)); 74 75 down_read(&pci_bus_sem); 76 list_for_each_entry(dev, &slot->bus->devices, bus_list) 77 if (PCI_SLOT(dev->devfn) == slot->number) 78 dev->slot = NULL; 79 up_read(&pci_bus_sem); 80 81 list_del(&slot->list); 82 83 kfree(slot); 84 } 85 86 static struct pci_slot_attribute pci_slot_attr_address = 87 __ATTR(address, S_IRUGO, address_read_file, NULL); 88 static struct pci_slot_attribute pci_slot_attr_max_speed = 89 __ATTR(max_bus_speed, S_IRUGO, max_speed_read_file, NULL); 90 static struct pci_slot_attribute pci_slot_attr_cur_speed = 91 __ATTR(cur_bus_speed, S_IRUGO, cur_speed_read_file, NULL); 92 93 static struct attribute *pci_slot_default_attrs[] = { 94 &pci_slot_attr_address.attr, 95 &pci_slot_attr_max_speed.attr, 96 &pci_slot_attr_cur_speed.attr, 97 NULL, 98 }; 99 ATTRIBUTE_GROUPS(pci_slot_default); 100 101 static struct kobj_type pci_slot_ktype = { 102 .sysfs_ops = &pci_slot_sysfs_ops, 103 .release = &pci_slot_release, 104 .default_groups = pci_slot_default_groups, 105 }; 106 107 static char *make_slot_name(const char *name) 108 { 109 char *new_name; 110 int len, max, dup; 111 112 new_name = kstrdup(name, GFP_KERNEL); 113 if (!new_name) 114 return NULL; 115 116 /* 117 * Make sure we hit the realloc case the first time through the 118 * loop. 'len' will be strlen(name) + 3 at that point which is 119 * enough space for "name-X" and the trailing NUL. 120 */ 121 len = strlen(name) + 2; 122 max = 1; 123 dup = 1; 124 125 for (;;) { 126 struct kobject *dup_slot; 127 dup_slot = kset_find_obj(pci_slots_kset, new_name); 128 if (!dup_slot) 129 break; 130 kobject_put(dup_slot); 131 if (dup == max) { 132 len++; 133 max *= 10; 134 kfree(new_name); 135 new_name = kmalloc(len, GFP_KERNEL); 136 if (!new_name) 137 break; 138 } 139 sprintf(new_name, "%s-%d", name, dup++); 140 } 141 142 return new_name; 143 } 144 145 static int rename_slot(struct pci_slot *slot, const char *name) 146 { 147 int result = 0; 148 char *slot_name; 149 150 if (strcmp(pci_slot_name(slot), name) == 0) 151 return result; 152 153 slot_name = make_slot_name(name); 154 if (!slot_name) 155 return -ENOMEM; 156 157 result = kobject_rename(&slot->kobj, slot_name); 158 kfree(slot_name); 159 160 return result; 161 } 162 163 void pci_dev_assign_slot(struct pci_dev *dev) 164 { 165 struct pci_slot *slot; 166 167 mutex_lock(&pci_slot_mutex); 168 list_for_each_entry(slot, &dev->bus->slots, list) 169 if (PCI_SLOT(dev->devfn) == slot->number) 170 dev->slot = slot; 171 mutex_unlock(&pci_slot_mutex); 172 } 173 174 static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr) 175 { 176 struct pci_slot *slot; 177 178 /* We already hold pci_slot_mutex */ 179 list_for_each_entry(slot, &parent->slots, list) 180 if (slot->number == slot_nr) { 181 kobject_get(&slot->kobj); 182 return slot; 183 } 184 185 return NULL; 186 } 187 188 /** 189 * pci_create_slot - create or increment refcount for physical PCI slot 190 * @parent: struct pci_bus of parent bridge 191 * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder 192 * @name: user visible string presented in /sys/bus/pci/slots/<name> 193 * @hotplug: set if caller is hotplug driver, NULL otherwise 194 * 195 * PCI slots have first class attributes such as address, speed, width, 196 * and a &struct pci_slot is used to manage them. This interface will 197 * either return a new &struct pci_slot to the caller, or if the pci_slot 198 * already exists, its refcount will be incremented. 199 * 200 * Slots are uniquely identified by a @pci_bus, @slot_nr tuple. 201 * 202 * There are known platforms with broken firmware that assign the same 203 * name to multiple slots. Workaround these broken platforms by renaming 204 * the slots on behalf of the caller. If firmware assigns name N to 205 * multiple slots: 206 * 207 * The first slot is assigned N 208 * The second slot is assigned N-1 209 * The third slot is assigned N-2 210 * etc. 211 * 212 * Placeholder slots: 213 * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify 214 * a slot. There is one notable exception - pSeries (rpaphp), where the 215 * @slot_nr cannot be determined until a device is actually inserted into 216 * the slot. In this scenario, the caller may pass -1 for @slot_nr. 217 * 218 * The following semantics are imposed when the caller passes @slot_nr == 219 * -1. First, we no longer check for an existing %struct pci_slot, as there 220 * may be many slots with @slot_nr of -1. The other change in semantics is 221 * user-visible, which is the 'address' parameter presented in sysfs will 222 * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the 223 * %struct pci_bus and bb is the bus number. In other words, the devfn of 224 * the 'placeholder' slot will not be displayed. 225 */ 226 struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr, 227 const char *name, 228 struct hotplug_slot *hotplug) 229 { 230 struct pci_dev *dev; 231 struct pci_slot *slot; 232 int err = 0; 233 char *slot_name = NULL; 234 235 mutex_lock(&pci_slot_mutex); 236 237 if (slot_nr == -1) 238 goto placeholder; 239 240 /* 241 * Hotplug drivers are allowed to rename an existing slot, 242 * but only if not already claimed. 243 */ 244 slot = get_slot(parent, slot_nr); 245 if (slot) { 246 if (hotplug) { 247 if ((err = slot->hotplug ? -EBUSY : 0) 248 || (err = rename_slot(slot, name))) { 249 kobject_put(&slot->kobj); 250 slot = NULL; 251 goto err; 252 } 253 } 254 goto out; 255 } 256 257 placeholder: 258 slot = kzalloc(sizeof(*slot), GFP_KERNEL); 259 if (!slot) { 260 err = -ENOMEM; 261 goto err; 262 } 263 264 slot->bus = parent; 265 slot->number = slot_nr; 266 267 slot->kobj.kset = pci_slots_kset; 268 269 slot_name = make_slot_name(name); 270 if (!slot_name) { 271 err = -ENOMEM; 272 kfree(slot); 273 goto err; 274 } 275 276 INIT_LIST_HEAD(&slot->list); 277 list_add(&slot->list, &parent->slots); 278 279 err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL, 280 "%s", slot_name); 281 if (err) { 282 kobject_put(&slot->kobj); 283 goto err; 284 } 285 286 down_read(&pci_bus_sem); 287 list_for_each_entry(dev, &parent->devices, bus_list) 288 if (PCI_SLOT(dev->devfn) == slot_nr) 289 dev->slot = slot; 290 up_read(&pci_bus_sem); 291 292 dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n", 293 slot_nr, pci_slot_name(slot)); 294 295 out: 296 kfree(slot_name); 297 mutex_unlock(&pci_slot_mutex); 298 return slot; 299 err: 300 slot = ERR_PTR(err); 301 goto out; 302 } 303 EXPORT_SYMBOL_GPL(pci_create_slot); 304 305 /** 306 * pci_destroy_slot - decrement refcount for physical PCI slot 307 * @slot: struct pci_slot to decrement 308 * 309 * %struct pci_slot is refcounted, so destroying them is really easy; we 310 * just call kobject_put on its kobj and let our release methods do the 311 * rest. 312 */ 313 void pci_destroy_slot(struct pci_slot *slot) 314 { 315 dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n", 316 slot->number, kref_read(&slot->kobj.kref) - 1); 317 318 mutex_lock(&pci_slot_mutex); 319 kobject_put(&slot->kobj); 320 mutex_unlock(&pci_slot_mutex); 321 } 322 EXPORT_SYMBOL_GPL(pci_destroy_slot); 323 324 #if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE) 325 #include <linux/pci_hotplug.h> 326 /** 327 * pci_hp_create_module_link - create symbolic link to hotplug driver module 328 * @pci_slot: struct pci_slot 329 * 330 * Helper function for pci_hotplug_core.c to create symbolic link to 331 * the hotplug driver module. 332 */ 333 void pci_hp_create_module_link(struct pci_slot *pci_slot) 334 { 335 struct hotplug_slot *slot = pci_slot->hotplug; 336 struct kobject *kobj = NULL; 337 int ret; 338 339 if (!slot || !slot->ops) 340 return; 341 kobj = kset_find_obj(module_kset, slot->mod_name); 342 if (!kobj) 343 return; 344 ret = sysfs_create_link(&pci_slot->kobj, kobj, "module"); 345 if (ret) 346 dev_err(&pci_slot->bus->dev, "Error creating sysfs link (%d)\n", 347 ret); 348 kobject_put(kobj); 349 } 350 EXPORT_SYMBOL_GPL(pci_hp_create_module_link); 351 352 /** 353 * pci_hp_remove_module_link - remove symbolic link to the hotplug driver 354 * module. 355 * @pci_slot: struct pci_slot 356 * 357 * Helper function for pci_hotplug_core.c to remove symbolic link to 358 * the hotplug driver module. 359 */ 360 void pci_hp_remove_module_link(struct pci_slot *pci_slot) 361 { 362 sysfs_remove_link(&pci_slot->kobj, "module"); 363 } 364 EXPORT_SYMBOL_GPL(pci_hp_remove_module_link); 365 #endif 366 367 static int pci_slot_init(void) 368 { 369 struct kset *pci_bus_kset; 370 371 pci_bus_kset = bus_get_kset(&pci_bus_type); 372 pci_slots_kset = kset_create_and_add("slots", NULL, 373 &pci_bus_kset->kobj); 374 if (!pci_slots_kset) { 375 pr_err("PCI: Slot initialization failure\n"); 376 return -ENOMEM; 377 } 378 return 0; 379 } 380 381 subsys_initcall(pci_slot_init); 382