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