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/pci.h> 11 #include <linux/err.h> 12 #include "pci.h" 13 14 struct kset *pci_slots_kset; 15 EXPORT_SYMBOL_GPL(pci_slots_kset); 16 17 static ssize_t pci_slot_attr_show(struct kobject *kobj, 18 struct attribute *attr, char *buf) 19 { 20 struct pci_slot *slot = to_pci_slot(kobj); 21 struct pci_slot_attribute *attribute = to_pci_slot_attr(attr); 22 return attribute->show ? attribute->show(slot, buf) : -EIO; 23 } 24 25 static ssize_t pci_slot_attr_store(struct kobject *kobj, 26 struct attribute *attr, const char *buf, size_t len) 27 { 28 struct pci_slot *slot = to_pci_slot(kobj); 29 struct pci_slot_attribute *attribute = to_pci_slot_attr(attr); 30 return attribute->store ? attribute->store(slot, buf, len) : -EIO; 31 } 32 33 static const struct sysfs_ops pci_slot_sysfs_ops = { 34 .show = pci_slot_attr_show, 35 .store = pci_slot_attr_store, 36 }; 37 38 static ssize_t address_read_file(struct pci_slot *slot, char *buf) 39 { 40 if (slot->number == PCI_SLOT_PLACEHOLDER) 41 return sysfs_emit(buf, "%04x:%02x\n", 42 pci_domain_nr(slot->bus), 43 slot->bus->number); 44 45 /* 46 * Preserve legacy ABI expectations that hotplug drivers that manage 47 * multiple devices per slot emit 0 for the device number. 48 */ 49 if (slot->number == PCI_SLOT_ALL_DEVICES) 50 return sysfs_emit(buf, "%04x:%02x:00\n", 51 pci_domain_nr(slot->bus), 52 slot->bus->number); 53 54 return sysfs_emit(buf, "%04x:%02x:%02x\n", 55 pci_domain_nr(slot->bus), 56 slot->bus->number, 57 slot->number); 58 } 59 60 static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf) 61 { 62 return sysfs_emit(buf, "%s\n", pci_speed_string(speed)); 63 } 64 65 static ssize_t max_speed_read_file(struct pci_slot *slot, char *buf) 66 { 67 return bus_speed_read(slot->bus->max_bus_speed, buf); 68 } 69 70 static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf) 71 { 72 return bus_speed_read(slot->bus->cur_bus_speed, buf); 73 } 74 75 static bool pci_dev_matches_slot(struct pci_dev *dev, struct pci_slot *slot) 76 { 77 if (slot->per_func_slot) 78 return dev->devfn == slot->number; 79 80 return slot->number == PCI_SLOT_ALL_DEVICES || 81 PCI_SLOT(dev->devfn) == slot->number; 82 } 83 84 static bool pci_slot_enabled_per_func(void) 85 { 86 if (IS_ENABLED(CONFIG_S390)) 87 return true; 88 89 return false; 90 } 91 92 static void pci_slot_release(struct kobject *kobj) 93 { 94 struct pci_dev *dev; 95 struct pci_slot *slot = to_pci_slot(kobj); 96 97 dev_dbg(&slot->bus->dev, "dev %02x, released physical slot %s\n", 98 slot->number, pci_slot_name(slot)); 99 100 down_read(&pci_bus_sem); 101 list_for_each_entry(dev, &slot->bus->devices, bus_list) 102 if (pci_dev_matches_slot(dev, slot)) 103 dev->slot = NULL; 104 up_read(&pci_bus_sem); 105 106 list_del(&slot->list); 107 pci_bus_put(slot->bus); 108 109 kfree(slot); 110 } 111 112 static struct pci_slot_attribute pci_slot_attr_address = 113 __ATTR(address, S_IRUGO, address_read_file, NULL); 114 static struct pci_slot_attribute pci_slot_attr_max_speed = 115 __ATTR(max_bus_speed, S_IRUGO, max_speed_read_file, NULL); 116 static struct pci_slot_attribute pci_slot_attr_cur_speed = 117 __ATTR(cur_bus_speed, S_IRUGO, cur_speed_read_file, NULL); 118 119 static struct attribute *pci_slot_default_attrs[] = { 120 &pci_slot_attr_address.attr, 121 &pci_slot_attr_max_speed.attr, 122 &pci_slot_attr_cur_speed.attr, 123 NULL, 124 }; 125 126 static const struct attribute_group pci_slot_default_group = { 127 .attrs = pci_slot_default_attrs, 128 }; 129 130 static const struct attribute_group *pci_slot_default_groups[] = { 131 &pci_slot_default_group, 132 #ifdef ARCH_PCI_SLOT_GROUPS 133 ARCH_PCI_SLOT_GROUPS, 134 #endif 135 NULL, 136 }; 137 138 static const struct kobj_type pci_slot_ktype = { 139 .sysfs_ops = &pci_slot_sysfs_ops, 140 .release = &pci_slot_release, 141 .default_groups = pci_slot_default_groups, 142 }; 143 144 static char *make_slot_name(const char *name) 145 { 146 char *new_name; 147 int len, max, dup; 148 149 new_name = kstrdup(name, GFP_KERNEL); 150 if (!new_name) 151 return NULL; 152 153 /* 154 * Make sure we hit the realloc case the first time through the 155 * loop. 'len' will be strlen(name) + 3 at that point which is 156 * enough space for "name-X" and the trailing NUL. 157 */ 158 len = strlen(name) + 2; 159 max = 1; 160 dup = 1; 161 162 for (;;) { 163 struct kobject *dup_slot; 164 dup_slot = kset_find_obj(pci_slots_kset, new_name); 165 if (!dup_slot) 166 break; 167 kobject_put(dup_slot); 168 if (dup == max) { 169 len++; 170 max *= 10; 171 kfree(new_name); 172 new_name = kmalloc(len, GFP_KERNEL); 173 if (!new_name) 174 break; 175 } 176 sprintf(new_name, "%s-%d", name, dup++); 177 } 178 179 return new_name; 180 } 181 182 static int rename_slot(struct pci_slot *slot, const char *name) 183 { 184 int result = 0; 185 char *slot_name; 186 187 if (strcmp(pci_slot_name(slot), name) == 0) 188 return result; 189 190 slot_name = make_slot_name(name); 191 if (!slot_name) 192 return -ENOMEM; 193 194 result = kobject_rename(&slot->kobj, slot_name); 195 kfree(slot_name); 196 197 return result; 198 } 199 200 void pci_dev_assign_slot(struct pci_dev *dev) 201 { 202 struct pci_slot *slot; 203 204 mutex_lock(&pci_slot_mutex); 205 list_for_each_entry(slot, &dev->bus->slots, list) 206 if (pci_dev_matches_slot(dev, slot)) 207 dev->slot = slot; 208 mutex_unlock(&pci_slot_mutex); 209 } 210 211 static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr) 212 { 213 struct pci_slot *slot; 214 215 /* We already hold pci_slot_mutex */ 216 list_for_each_entry(slot, &parent->slots, list) 217 if (slot->number == slot_nr) { 218 kobject_get(&slot->kobj); 219 return slot; 220 } 221 222 return NULL; 223 } 224 225 /** 226 * pci_create_slot - create or increment refcount for physical PCI slot 227 * @parent: struct pci_bus of parent bridge 228 * @slot_nr: PCI_SLOT(pci_dev->devfn), PCI_SLOT_PLACEHOLDER for placeholder, or 229 * PCI_SLOT_ALL_DEVICES 230 * @name: user visible string presented in /sys/bus/pci/slots/<name> 231 * @hotplug: set if caller is hotplug driver, NULL otherwise 232 * 233 * PCI slots have first class attributes such as address, speed, width, 234 * and a &struct pci_slot is used to manage them. This interface will 235 * either return a new &struct pci_slot to the caller, or if the pci_slot 236 * already exists, its refcount will be incremented. 237 * 238 * Slots are uniquely identified by a @pci_bus, @slot_nr tuple. 239 * 240 * There are known platforms with broken firmware that assign the same 241 * name to multiple slots. Workaround these broken platforms by renaming 242 * the slots on behalf of the caller. If firmware assigns name N to 243 * multiple slots: 244 * 245 * The first slot is assigned N 246 * The second slot is assigned N-1 247 * The third slot is assigned N-2 248 * etc. 249 * 250 * Placeholder slots: 251 * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify 252 * a slot. There is one notable exception - pSeries (rpaphp), where the 253 * @slot_nr cannot be determined until a device is actually inserted into 254 * the slot. In this scenario, the caller may pass PCI_SLOT_PLACEHOLDER for @slot_nr. 255 * 256 * The following semantics are imposed when the caller passes @slot_nr == 257 * PCI_SLOT_PLACEHOLDER. First, we no longer check for an existing %struct 258 * pci_slot, as there may be many slots with @slot_nr of 259 * PCI_SLOT_PLACEHOLDER. The other change in semantics is user-visible, 260 * which is the 'address' parameter presented in sysfs will consist solely 261 * of a dddd:bb tuple, where dddd is the PCI domain of the %struct pci_bus 262 * and bb is the bus number. In other words, the devfn of the 'placeholder' 263 * slot will not be displayed. 264 * 265 * Bus-wide slots: 266 * For PCIe hotplug, the physical slot encompasses the entire secondary 267 * bus, not just a single device number. If the device supports ARI and ARI 268 * Forwarding is enabled in the upstream bridge, a multi-function device 269 * may include functions that appear to have several different device 270 * numbers, i.e., PCI_SLOT() values. Pass @slot_nr == PCI_SLOT_ALL_DEVICES 271 * to create a slot that matches all devices on the bus. Unlike placeholder 272 * slots, bus-wide slots go through normal slot lookup and reuse existing 273 * slots if present. 274 */ 275 struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr, 276 const char *name, 277 struct hotplug_slot *hotplug) 278 { 279 struct pci_dev *dev; 280 struct pci_slot *slot; 281 int err = 0; 282 char *slot_name = NULL; 283 284 mutex_lock(&pci_slot_mutex); 285 286 if (slot_nr == PCI_SLOT_PLACEHOLDER) 287 goto placeholder; 288 289 /* 290 * Hotplug drivers are allowed to rename an existing slot, 291 * but only if not already claimed. 292 */ 293 slot = get_slot(parent, slot_nr); 294 if (slot) { 295 if (hotplug) { 296 if (slot->hotplug) { 297 err = -EBUSY; 298 goto put_slot; 299 } 300 err = rename_slot(slot, name); 301 if (err) 302 goto put_slot; 303 } 304 goto out; 305 } 306 307 placeholder: 308 slot = kzalloc_obj(*slot); 309 if (!slot) { 310 err = -ENOMEM; 311 goto err; 312 } 313 314 slot->bus = pci_bus_get(parent); 315 slot->number = slot_nr; 316 317 if (pci_slot_enabled_per_func()) 318 slot->per_func_slot = 1; 319 320 slot->kobj.kset = pci_slots_kset; 321 322 slot_name = make_slot_name(name); 323 if (!slot_name) { 324 err = -ENOMEM; 325 pci_bus_put(slot->bus); 326 kfree(slot); 327 goto err; 328 } 329 330 INIT_LIST_HEAD(&slot->list); 331 list_add(&slot->list, &parent->slots); 332 333 err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL, 334 "%s", slot_name); 335 if (err) 336 goto put_slot; 337 338 down_read(&pci_bus_sem); 339 list_for_each_entry(dev, &parent->devices, bus_list) 340 if (pci_dev_matches_slot(dev, slot)) 341 dev->slot = slot; 342 up_read(&pci_bus_sem); 343 344 dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n", 345 slot_nr, pci_slot_name(slot)); 346 347 out: 348 kfree(slot_name); 349 mutex_unlock(&pci_slot_mutex); 350 return slot; 351 352 put_slot: 353 kobject_put(&slot->kobj); 354 err: 355 slot = ERR_PTR(err); 356 goto out; 357 } 358 EXPORT_SYMBOL_GPL(pci_create_slot); 359 360 /** 361 * pci_destroy_slot - decrement refcount for physical PCI slot 362 * @slot: struct pci_slot to decrement 363 * 364 * %struct pci_slot is refcounted, so destroying them is really easy; we 365 * just call kobject_put on its kobj and let our release methods do the 366 * rest. 367 */ 368 void pci_destroy_slot(struct pci_slot *slot) 369 { 370 dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n", 371 slot->number, kref_read(&slot->kobj.kref) - 1); 372 373 mutex_lock(&pci_slot_mutex); 374 kobject_put(&slot->kobj); 375 mutex_unlock(&pci_slot_mutex); 376 } 377 EXPORT_SYMBOL_GPL(pci_destroy_slot); 378 379 static int pci_slot_init(void) 380 { 381 struct kset *pci_bus_kset; 382 383 pci_bus_kset = bus_get_kset(&pci_bus_type); 384 pci_slots_kset = kset_create_and_add("slots", NULL, 385 &pci_bus_kset->kobj); 386 if (!pci_slots_kset) { 387 pr_err("PCI: Slot initialization failure\n"); 388 return -ENOMEM; 389 } 390 return 0; 391 } 392 393 subsys_initcall(pci_slot_init); 394