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 pci_bus_put(slot->bus); 83 84 kfree(slot); 85 } 86 87 static struct pci_slot_attribute pci_slot_attr_address = 88 __ATTR(address, S_IRUGO, address_read_file, NULL); 89 static struct pci_slot_attribute pci_slot_attr_max_speed = 90 __ATTR(max_bus_speed, S_IRUGO, max_speed_read_file, NULL); 91 static struct pci_slot_attribute pci_slot_attr_cur_speed = 92 __ATTR(cur_bus_speed, S_IRUGO, cur_speed_read_file, NULL); 93 94 static struct attribute *pci_slot_default_attrs[] = { 95 &pci_slot_attr_address.attr, 96 &pci_slot_attr_max_speed.attr, 97 &pci_slot_attr_cur_speed.attr, 98 NULL, 99 }; 100 ATTRIBUTE_GROUPS(pci_slot_default); 101 102 static const struct kobj_type pci_slot_ktype = { 103 .sysfs_ops = &pci_slot_sysfs_ops, 104 .release = &pci_slot_release, 105 .default_groups = pci_slot_default_groups, 106 }; 107 108 static char *make_slot_name(const char *name) 109 { 110 char *new_name; 111 int len, max, dup; 112 113 new_name = kstrdup(name, GFP_KERNEL); 114 if (!new_name) 115 return NULL; 116 117 /* 118 * Make sure we hit the realloc case the first time through the 119 * loop. 'len' will be strlen(name) + 3 at that point which is 120 * enough space for "name-X" and the trailing NUL. 121 */ 122 len = strlen(name) + 2; 123 max = 1; 124 dup = 1; 125 126 for (;;) { 127 struct kobject *dup_slot; 128 dup_slot = kset_find_obj(pci_slots_kset, new_name); 129 if (!dup_slot) 130 break; 131 kobject_put(dup_slot); 132 if (dup == max) { 133 len++; 134 max *= 10; 135 kfree(new_name); 136 new_name = kmalloc(len, GFP_KERNEL); 137 if (!new_name) 138 break; 139 } 140 sprintf(new_name, "%s-%d", name, dup++); 141 } 142 143 return new_name; 144 } 145 146 static int rename_slot(struct pci_slot *slot, const char *name) 147 { 148 int result = 0; 149 char *slot_name; 150 151 if (strcmp(pci_slot_name(slot), name) == 0) 152 return result; 153 154 slot_name = make_slot_name(name); 155 if (!slot_name) 156 return -ENOMEM; 157 158 result = kobject_rename(&slot->kobj, slot_name); 159 kfree(slot_name); 160 161 return result; 162 } 163 164 void pci_dev_assign_slot(struct pci_dev *dev) 165 { 166 struct pci_slot *slot; 167 168 mutex_lock(&pci_slot_mutex); 169 list_for_each_entry(slot, &dev->bus->slots, list) 170 if (PCI_SLOT(dev->devfn) == slot->number) 171 dev->slot = slot; 172 mutex_unlock(&pci_slot_mutex); 173 } 174 175 static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr) 176 { 177 struct pci_slot *slot; 178 179 /* We already hold pci_slot_mutex */ 180 list_for_each_entry(slot, &parent->slots, list) 181 if (slot->number == slot_nr) { 182 kobject_get(&slot->kobj); 183 return slot; 184 } 185 186 return NULL; 187 } 188 189 /** 190 * pci_create_slot - create or increment refcount for physical PCI slot 191 * @parent: struct pci_bus of parent bridge 192 * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder 193 * @name: user visible string presented in /sys/bus/pci/slots/<name> 194 * @hotplug: set if caller is hotplug driver, NULL otherwise 195 * 196 * PCI slots have first class attributes such as address, speed, width, 197 * and a &struct pci_slot is used to manage them. This interface will 198 * either return a new &struct pci_slot to the caller, or if the pci_slot 199 * already exists, its refcount will be incremented. 200 * 201 * Slots are uniquely identified by a @pci_bus, @slot_nr tuple. 202 * 203 * There are known platforms with broken firmware that assign the same 204 * name to multiple slots. Workaround these broken platforms by renaming 205 * the slots on behalf of the caller. If firmware assigns name N to 206 * multiple slots: 207 * 208 * The first slot is assigned N 209 * The second slot is assigned N-1 210 * The third slot is assigned N-2 211 * etc. 212 * 213 * Placeholder slots: 214 * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify 215 * a slot. There is one notable exception - pSeries (rpaphp), where the 216 * @slot_nr cannot be determined until a device is actually inserted into 217 * the slot. In this scenario, the caller may pass -1 for @slot_nr. 218 * 219 * The following semantics are imposed when the caller passes @slot_nr == 220 * -1. First, we no longer check for an existing %struct pci_slot, as there 221 * may be many slots with @slot_nr of -1. The other change in semantics is 222 * user-visible, which is the 'address' parameter presented in sysfs will 223 * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the 224 * %struct pci_bus and bb is the bus number. In other words, the devfn of 225 * the 'placeholder' slot will not be displayed. 226 */ 227 struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr, 228 const char *name, 229 struct hotplug_slot *hotplug) 230 { 231 struct pci_dev *dev; 232 struct pci_slot *slot; 233 int err = 0; 234 char *slot_name = NULL; 235 236 mutex_lock(&pci_slot_mutex); 237 238 if (slot_nr == -1) 239 goto placeholder; 240 241 /* 242 * Hotplug drivers are allowed to rename an existing slot, 243 * but only if not already claimed. 244 */ 245 slot = get_slot(parent, slot_nr); 246 if (slot) { 247 if (hotplug) { 248 if (slot->hotplug) { 249 err = -EBUSY; 250 goto put_slot; 251 } 252 err = rename_slot(slot, name); 253 if (err) 254 goto put_slot; 255 } 256 goto out; 257 } 258 259 placeholder: 260 slot = kzalloc(sizeof(*slot), GFP_KERNEL); 261 if (!slot) { 262 err = -ENOMEM; 263 goto err; 264 } 265 266 slot->bus = pci_bus_get(parent); 267 slot->number = slot_nr; 268 269 slot->kobj.kset = pci_slots_kset; 270 271 slot_name = make_slot_name(name); 272 if (!slot_name) { 273 err = -ENOMEM; 274 pci_bus_put(slot->bus); 275 kfree(slot); 276 goto err; 277 } 278 279 INIT_LIST_HEAD(&slot->list); 280 list_add(&slot->list, &parent->slots); 281 282 err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL, 283 "%s", slot_name); 284 if (err) 285 goto put_slot; 286 287 down_read(&pci_bus_sem); 288 list_for_each_entry(dev, &parent->devices, bus_list) 289 if (PCI_SLOT(dev->devfn) == slot_nr) 290 dev->slot = slot; 291 up_read(&pci_bus_sem); 292 293 dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n", 294 slot_nr, pci_slot_name(slot)); 295 296 out: 297 kfree(slot_name); 298 mutex_unlock(&pci_slot_mutex); 299 return slot; 300 301 put_slot: 302 kobject_put(&slot->kobj); 303 err: 304 slot = ERR_PTR(err); 305 goto out; 306 } 307 EXPORT_SYMBOL_GPL(pci_create_slot); 308 309 /** 310 * pci_destroy_slot - decrement refcount for physical PCI slot 311 * @slot: struct pci_slot to decrement 312 * 313 * %struct pci_slot is refcounted, so destroying them is really easy; we 314 * just call kobject_put on its kobj and let our release methods do the 315 * rest. 316 */ 317 void pci_destroy_slot(struct pci_slot *slot) 318 { 319 dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n", 320 slot->number, kref_read(&slot->kobj.kref) - 1); 321 322 mutex_lock(&pci_slot_mutex); 323 kobject_put(&slot->kobj); 324 mutex_unlock(&pci_slot_mutex); 325 } 326 EXPORT_SYMBOL_GPL(pci_destroy_slot); 327 328 #if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE) 329 #include <linux/pci_hotplug.h> 330 /** 331 * pci_hp_create_module_link - create symbolic link to hotplug driver module 332 * @pci_slot: struct pci_slot 333 * 334 * Helper function for pci_hotplug_core.c to create symbolic link to 335 * the hotplug driver module. 336 */ 337 void pci_hp_create_module_link(struct pci_slot *pci_slot) 338 { 339 struct hotplug_slot *slot = pci_slot->hotplug; 340 struct kobject *kobj = NULL; 341 int ret; 342 343 if (!slot || !slot->ops) 344 return; 345 kobj = kset_find_obj(module_kset, slot->mod_name); 346 if (!kobj) 347 return; 348 ret = sysfs_create_link(&pci_slot->kobj, kobj, "module"); 349 if (ret) 350 dev_err(&pci_slot->bus->dev, "Error creating sysfs link (%d)\n", 351 ret); 352 kobject_put(kobj); 353 } 354 EXPORT_SYMBOL_GPL(pci_hp_create_module_link); 355 356 /** 357 * pci_hp_remove_module_link - remove symbolic link to the hotplug driver 358 * module. 359 * @pci_slot: struct pci_slot 360 * 361 * Helper function for pci_hotplug_core.c to remove symbolic link to 362 * the hotplug driver module. 363 */ 364 void pci_hp_remove_module_link(struct pci_slot *pci_slot) 365 { 366 sysfs_remove_link(&pci_slot->kobj, "module"); 367 } 368 EXPORT_SYMBOL_GPL(pci_hp_remove_module_link); 369 #endif 370 371 static int pci_slot_init(void) 372 { 373 struct kset *pci_bus_kset; 374 375 pci_bus_kset = bus_get_kset(&pci_bus_type); 376 pci_slots_kset = kset_create_and_add("slots", NULL, 377 &pci_bus_kset->kobj); 378 if (!pci_slots_kset) { 379 pr_err("PCI: Slot initialization failure\n"); 380 return -ENOMEM; 381 } 382 return 0; 383 } 384 385 subsys_initcall(pci_slot_init); 386