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 sprintf(buf, "%04x:%02x\n", 43 pci_domain_nr(slot->bus), 44 slot->bus->number); 45 else 46 return sprintf(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 sprintf(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 }; 99 100 static struct kobj_type pci_slot_ktype = { 101 .sysfs_ops = &pci_slot_sysfs_ops, 102 .release = &pci_slot_release, 103 .default_attrs = pci_slot_default_attrs, 104 }; 105 106 static char *make_slot_name(const char *name) 107 { 108 char *new_name; 109 int len, max, dup; 110 111 new_name = kstrdup(name, GFP_KERNEL); 112 if (!new_name) 113 return NULL; 114 115 /* 116 * Make sure we hit the realloc case the first time through the 117 * loop. 'len' will be strlen(name) + 3 at that point which is 118 * enough space for "name-X" and the trailing NUL. 119 */ 120 len = strlen(name) + 2; 121 max = 1; 122 dup = 1; 123 124 for (;;) { 125 struct kobject *dup_slot; 126 dup_slot = kset_find_obj(pci_slots_kset, new_name); 127 if (!dup_slot) 128 break; 129 kobject_put(dup_slot); 130 if (dup == max) { 131 len++; 132 max *= 10; 133 kfree(new_name); 134 new_name = kmalloc(len, GFP_KERNEL); 135 if (!new_name) 136 break; 137 } 138 sprintf(new_name, "%s-%d", name, dup++); 139 } 140 141 return new_name; 142 } 143 144 static int rename_slot(struct pci_slot *slot, const char *name) 145 { 146 int result = 0; 147 char *slot_name; 148 149 if (strcmp(pci_slot_name(slot), name) == 0) 150 return result; 151 152 slot_name = make_slot_name(name); 153 if (!slot_name) 154 return -ENOMEM; 155 156 result = kobject_rename(&slot->kobj, slot_name); 157 kfree(slot_name); 158 159 return result; 160 } 161 162 void pci_dev_assign_slot(struct pci_dev *dev) 163 { 164 struct pci_slot *slot; 165 166 mutex_lock(&pci_slot_mutex); 167 list_for_each_entry(slot, &dev->bus->slots, list) 168 if (PCI_SLOT(dev->devfn) == slot->number) 169 dev->slot = slot; 170 mutex_unlock(&pci_slot_mutex); 171 } 172 173 static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr) 174 { 175 struct pci_slot *slot; 176 177 /* We already hold pci_slot_mutex */ 178 list_for_each_entry(slot, &parent->slots, list) 179 if (slot->number == slot_nr) { 180 kobject_get(&slot->kobj); 181 return slot; 182 } 183 184 return NULL; 185 } 186 187 /** 188 * pci_create_slot - create or increment refcount for physical PCI slot 189 * @parent: struct pci_bus of parent bridge 190 * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder 191 * @name: user visible string presented in /sys/bus/pci/slots/<name> 192 * @hotplug: set if caller is hotplug driver, NULL otherwise 193 * 194 * PCI slots have first class attributes such as address, speed, width, 195 * and a &struct pci_slot is used to manage them. This interface will 196 * either return a new &struct pci_slot to the caller, or if the pci_slot 197 * already exists, its refcount will be incremented. 198 * 199 * Slots are uniquely identified by a @pci_bus, @slot_nr tuple. 200 * 201 * There are known platforms with broken firmware that assign the same 202 * name to multiple slots. Workaround these broken platforms by renaming 203 * the slots on behalf of the caller. If firmware assigns name N to 204 * multiple slots: 205 * 206 * The first slot is assigned N 207 * The second slot is assigned N-1 208 * The third slot is assigned N-2 209 * etc. 210 * 211 * Placeholder slots: 212 * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify 213 * a slot. There is one notable exception - pSeries (rpaphp), where the 214 * @slot_nr cannot be determined until a device is actually inserted into 215 * the slot. In this scenario, the caller may pass -1 for @slot_nr. 216 * 217 * The following semantics are imposed when the caller passes @slot_nr == 218 * -1. First, we no longer check for an existing %struct pci_slot, as there 219 * may be many slots with @slot_nr of -1. The other change in semantics is 220 * user-visible, which is the 'address' parameter presented in sysfs will 221 * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the 222 * %struct pci_bus and bb is the bus number. In other words, the devfn of 223 * the 'placeholder' slot will not be displayed. 224 */ 225 struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr, 226 const char *name, 227 struct hotplug_slot *hotplug) 228 { 229 struct pci_dev *dev; 230 struct pci_slot *slot; 231 int err = 0; 232 char *slot_name = NULL; 233 234 mutex_lock(&pci_slot_mutex); 235 236 if (slot_nr == -1) 237 goto placeholder; 238 239 /* 240 * Hotplug drivers are allowed to rename an existing slot, 241 * but only if not already claimed. 242 */ 243 slot = get_slot(parent, slot_nr); 244 if (slot) { 245 if (hotplug) { 246 if ((err = slot->hotplug ? -EBUSY : 0) 247 || (err = rename_slot(slot, name))) { 248 kobject_put(&slot->kobj); 249 slot = NULL; 250 goto err; 251 } 252 } 253 goto out; 254 } 255 256 placeholder: 257 slot = kzalloc(sizeof(*slot), GFP_KERNEL); 258 if (!slot) { 259 err = -ENOMEM; 260 goto err; 261 } 262 263 slot->bus = parent; 264 slot->number = slot_nr; 265 266 slot->kobj.kset = pci_slots_kset; 267 268 slot_name = make_slot_name(name); 269 if (!slot_name) { 270 err = -ENOMEM; 271 goto err; 272 } 273 274 err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL, 275 "%s", slot_name); 276 if (err) 277 goto err; 278 279 INIT_LIST_HEAD(&slot->list); 280 list_add(&slot->list, &parent->slots); 281 282 down_read(&pci_bus_sem); 283 list_for_each_entry(dev, &parent->devices, bus_list) 284 if (PCI_SLOT(dev->devfn) == slot_nr) 285 dev->slot = slot; 286 up_read(&pci_bus_sem); 287 288 dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n", 289 slot_nr, pci_slot_name(slot)); 290 291 out: 292 kfree(slot_name); 293 mutex_unlock(&pci_slot_mutex); 294 return slot; 295 err: 296 kfree(slot); 297 slot = ERR_PTR(err); 298 goto out; 299 } 300 EXPORT_SYMBOL_GPL(pci_create_slot); 301 302 /** 303 * pci_destroy_slot - decrement refcount for physical PCI slot 304 * @slot: struct pci_slot to decrement 305 * 306 * %struct pci_slot is refcounted, so destroying them is really easy; we 307 * just call kobject_put on its kobj and let our release methods do the 308 * rest. 309 */ 310 void pci_destroy_slot(struct pci_slot *slot) 311 { 312 dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n", 313 slot->number, kref_read(&slot->kobj.kref) - 1); 314 315 mutex_lock(&pci_slot_mutex); 316 kobject_put(&slot->kobj); 317 mutex_unlock(&pci_slot_mutex); 318 } 319 EXPORT_SYMBOL_GPL(pci_destroy_slot); 320 321 #if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE) 322 #include <linux/pci_hotplug.h> 323 /** 324 * pci_hp_create_link - create symbolic link to the hotplug driver module. 325 * @pci_slot: struct pci_slot 326 * 327 * Helper function for pci_hotplug_core.c to create symbolic link to 328 * the hotplug driver module. 329 */ 330 void pci_hp_create_module_link(struct pci_slot *pci_slot) 331 { 332 struct hotplug_slot *slot = pci_slot->hotplug; 333 struct kobject *kobj = NULL; 334 int ret; 335 336 if (!slot || !slot->ops) 337 return; 338 kobj = kset_find_obj(module_kset, slot->mod_name); 339 if (!kobj) 340 return; 341 ret = sysfs_create_link(&pci_slot->kobj, kobj, "module"); 342 if (ret) 343 dev_err(&pci_slot->bus->dev, "Error creating sysfs link (%d)\n", 344 ret); 345 kobject_put(kobj); 346 } 347 EXPORT_SYMBOL_GPL(pci_hp_create_module_link); 348 349 /** 350 * pci_hp_remove_link - remove symbolic link to the hotplug driver module. 351 * @pci_slot: struct pci_slot 352 * 353 * Helper function for pci_hotplug_core.c to remove symbolic link to 354 * the hotplug driver module. 355 */ 356 void pci_hp_remove_module_link(struct pci_slot *pci_slot) 357 { 358 sysfs_remove_link(&pci_slot->kobj, "module"); 359 } 360 EXPORT_SYMBOL_GPL(pci_hp_remove_module_link); 361 #endif 362 363 static int pci_slot_init(void) 364 { 365 struct kset *pci_bus_kset; 366 367 pci_bus_kset = bus_get_kset(&pci_bus_type); 368 pci_slots_kset = kset_create_and_add("slots", NULL, 369 &pci_bus_kset->kobj); 370 if (!pci_slots_kset) { 371 pr_err("PCI: Slot initialization failure\n"); 372 return -ENOMEM; 373 } 374 return 0; 375 } 376 377 subsys_initcall(pci_slot_init); 378