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 /* these strings match up with the values in pci_bus_speed */ 53 static const char *pci_bus_speed_strings[] = { 54 "33 MHz PCI", /* 0x00 */ 55 "66 MHz PCI", /* 0x01 */ 56 "66 MHz PCI-X", /* 0x02 */ 57 "100 MHz PCI-X", /* 0x03 */ 58 "133 MHz PCI-X", /* 0x04 */ 59 NULL, /* 0x05 */ 60 NULL, /* 0x06 */ 61 NULL, /* 0x07 */ 62 NULL, /* 0x08 */ 63 "66 MHz PCI-X 266", /* 0x09 */ 64 "100 MHz PCI-X 266", /* 0x0a */ 65 "133 MHz PCI-X 266", /* 0x0b */ 66 "Unknown AGP", /* 0x0c */ 67 "1x AGP", /* 0x0d */ 68 "2x AGP", /* 0x0e */ 69 "4x AGP", /* 0x0f */ 70 "8x AGP", /* 0x10 */ 71 "66 MHz PCI-X 533", /* 0x11 */ 72 "100 MHz PCI-X 533", /* 0x12 */ 73 "133 MHz PCI-X 533", /* 0x13 */ 74 "2.5 GT/s PCIe", /* 0x14 */ 75 "5.0 GT/s PCIe", /* 0x15 */ 76 "8.0 GT/s PCIe", /* 0x16 */ 77 "16.0 GT/s PCIe", /* 0x17 */ 78 }; 79 80 static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf) 81 { 82 const char *speed_string; 83 84 if (speed < ARRAY_SIZE(pci_bus_speed_strings)) 85 speed_string = pci_bus_speed_strings[speed]; 86 else 87 speed_string = "Unknown"; 88 89 return sprintf(buf, "%s\n", speed_string); 90 } 91 92 static ssize_t max_speed_read_file(struct pci_slot *slot, char *buf) 93 { 94 return bus_speed_read(slot->bus->max_bus_speed, buf); 95 } 96 97 static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf) 98 { 99 return bus_speed_read(slot->bus->cur_bus_speed, buf); 100 } 101 102 static void pci_slot_release(struct kobject *kobj) 103 { 104 struct pci_dev *dev; 105 struct pci_slot *slot = to_pci_slot(kobj); 106 107 dev_dbg(&slot->bus->dev, "dev %02x, released physical slot %s\n", 108 slot->number, pci_slot_name(slot)); 109 110 down_read(&pci_bus_sem); 111 list_for_each_entry(dev, &slot->bus->devices, bus_list) 112 if (PCI_SLOT(dev->devfn) == slot->number) 113 dev->slot = NULL; 114 up_read(&pci_bus_sem); 115 116 list_del(&slot->list); 117 118 kfree(slot); 119 } 120 121 static struct pci_slot_attribute pci_slot_attr_address = 122 __ATTR(address, S_IRUGO, address_read_file, NULL); 123 static struct pci_slot_attribute pci_slot_attr_max_speed = 124 __ATTR(max_bus_speed, S_IRUGO, max_speed_read_file, NULL); 125 static struct pci_slot_attribute pci_slot_attr_cur_speed = 126 __ATTR(cur_bus_speed, S_IRUGO, cur_speed_read_file, NULL); 127 128 static struct attribute *pci_slot_default_attrs[] = { 129 &pci_slot_attr_address.attr, 130 &pci_slot_attr_max_speed.attr, 131 &pci_slot_attr_cur_speed.attr, 132 NULL, 133 }; 134 135 static struct kobj_type pci_slot_ktype = { 136 .sysfs_ops = &pci_slot_sysfs_ops, 137 .release = &pci_slot_release, 138 .default_attrs = pci_slot_default_attrs, 139 }; 140 141 static char *make_slot_name(const char *name) 142 { 143 char *new_name; 144 int len, max, dup; 145 146 new_name = kstrdup(name, GFP_KERNEL); 147 if (!new_name) 148 return NULL; 149 150 /* 151 * Make sure we hit the realloc case the first time through the 152 * loop. 'len' will be strlen(name) + 3 at that point which is 153 * enough space for "name-X" and the trailing NUL. 154 */ 155 len = strlen(name) + 2; 156 max = 1; 157 dup = 1; 158 159 for (;;) { 160 struct kobject *dup_slot; 161 dup_slot = kset_find_obj(pci_slots_kset, new_name); 162 if (!dup_slot) 163 break; 164 kobject_put(dup_slot); 165 if (dup == max) { 166 len++; 167 max *= 10; 168 kfree(new_name); 169 new_name = kmalloc(len, GFP_KERNEL); 170 if (!new_name) 171 break; 172 } 173 sprintf(new_name, "%s-%d", name, dup++); 174 } 175 176 return new_name; 177 } 178 179 static int rename_slot(struct pci_slot *slot, const char *name) 180 { 181 int result = 0; 182 char *slot_name; 183 184 if (strcmp(pci_slot_name(slot), name) == 0) 185 return result; 186 187 slot_name = make_slot_name(name); 188 if (!slot_name) 189 return -ENOMEM; 190 191 result = kobject_rename(&slot->kobj, slot_name); 192 kfree(slot_name); 193 194 return result; 195 } 196 197 void pci_dev_assign_slot(struct pci_dev *dev) 198 { 199 struct pci_slot *slot; 200 201 mutex_lock(&pci_slot_mutex); 202 list_for_each_entry(slot, &dev->bus->slots, list) 203 if (PCI_SLOT(dev->devfn) == slot->number) 204 dev->slot = slot; 205 mutex_unlock(&pci_slot_mutex); 206 } 207 208 static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr) 209 { 210 struct pci_slot *slot; 211 212 /* We already hold pci_slot_mutex */ 213 list_for_each_entry(slot, &parent->slots, list) 214 if (slot->number == slot_nr) { 215 kobject_get(&slot->kobj); 216 return slot; 217 } 218 219 return NULL; 220 } 221 222 /** 223 * pci_create_slot - create or increment refcount for physical PCI slot 224 * @parent: struct pci_bus of parent bridge 225 * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder 226 * @name: user visible string presented in /sys/bus/pci/slots/<name> 227 * @hotplug: set if caller is hotplug driver, NULL otherwise 228 * 229 * PCI slots have first class attributes such as address, speed, width, 230 * and a &struct pci_slot is used to manage them. This interface will 231 * either return a new &struct pci_slot to the caller, or if the pci_slot 232 * already exists, its refcount will be incremented. 233 * 234 * Slots are uniquely identified by a @pci_bus, @slot_nr tuple. 235 * 236 * There are known platforms with broken firmware that assign the same 237 * name to multiple slots. Workaround these broken platforms by renaming 238 * the slots on behalf of the caller. If firmware assigns name N to 239 * multiple slots: 240 * 241 * The first slot is assigned N 242 * The second slot is assigned N-1 243 * The third slot is assigned N-2 244 * etc. 245 * 246 * Placeholder slots: 247 * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify 248 * a slot. There is one notable exception - pSeries (rpaphp), where the 249 * @slot_nr cannot be determined until a device is actually inserted into 250 * the slot. In this scenario, the caller may pass -1 for @slot_nr. 251 * 252 * The following semantics are imposed when the caller passes @slot_nr == 253 * -1. First, we no longer check for an existing %struct pci_slot, as there 254 * may be many slots with @slot_nr of -1. The other change in semantics is 255 * user-visible, which is the 'address' parameter presented in sysfs will 256 * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the 257 * %struct pci_bus and bb is the bus number. In other words, the devfn of 258 * the 'placeholder' slot will not be displayed. 259 */ 260 struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr, 261 const char *name, 262 struct hotplug_slot *hotplug) 263 { 264 struct pci_dev *dev; 265 struct pci_slot *slot; 266 int err = 0; 267 char *slot_name = NULL; 268 269 mutex_lock(&pci_slot_mutex); 270 271 if (slot_nr == -1) 272 goto placeholder; 273 274 /* 275 * Hotplug drivers are allowed to rename an existing slot, 276 * but only if not already claimed. 277 */ 278 slot = get_slot(parent, slot_nr); 279 if (slot) { 280 if (hotplug) { 281 if ((err = slot->hotplug ? -EBUSY : 0) 282 || (err = rename_slot(slot, name))) { 283 kobject_put(&slot->kobj); 284 slot = NULL; 285 goto err; 286 } 287 } 288 goto out; 289 } 290 291 placeholder: 292 slot = kzalloc(sizeof(*slot), GFP_KERNEL); 293 if (!slot) { 294 err = -ENOMEM; 295 goto err; 296 } 297 298 slot->bus = 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 goto err; 307 } 308 309 err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL, 310 "%s", slot_name); 311 if (err) 312 goto err; 313 314 INIT_LIST_HEAD(&slot->list); 315 list_add(&slot->list, &parent->slots); 316 317 down_read(&pci_bus_sem); 318 list_for_each_entry(dev, &parent->devices, bus_list) 319 if (PCI_SLOT(dev->devfn) == slot_nr) 320 dev->slot = slot; 321 up_read(&pci_bus_sem); 322 323 dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n", 324 slot_nr, pci_slot_name(slot)); 325 326 out: 327 kfree(slot_name); 328 mutex_unlock(&pci_slot_mutex); 329 return slot; 330 err: 331 kfree(slot); 332 slot = ERR_PTR(err); 333 goto out; 334 } 335 EXPORT_SYMBOL_GPL(pci_create_slot); 336 337 /** 338 * pci_destroy_slot - decrement refcount for physical PCI slot 339 * @slot: struct pci_slot to decrement 340 * 341 * %struct pci_slot is refcounted, so destroying them is really easy; we 342 * just call kobject_put on its kobj and let our release methods do the 343 * rest. 344 */ 345 void pci_destroy_slot(struct pci_slot *slot) 346 { 347 dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n", 348 slot->number, kref_read(&slot->kobj.kref) - 1); 349 350 mutex_lock(&pci_slot_mutex); 351 kobject_put(&slot->kobj); 352 mutex_unlock(&pci_slot_mutex); 353 } 354 EXPORT_SYMBOL_GPL(pci_destroy_slot); 355 356 #if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE) 357 #include <linux/pci_hotplug.h> 358 /** 359 * pci_hp_create_link - create symbolic link to the hotplug driver module. 360 * @pci_slot: struct pci_slot 361 * 362 * Helper function for pci_hotplug_core.c to create symbolic link to 363 * the hotplug driver module. 364 */ 365 void pci_hp_create_module_link(struct pci_slot *pci_slot) 366 { 367 struct hotplug_slot *slot = pci_slot->hotplug; 368 struct kobject *kobj = NULL; 369 int ret; 370 371 if (!slot || !slot->ops) 372 return; 373 kobj = kset_find_obj(module_kset, slot->mod_name); 374 if (!kobj) 375 return; 376 ret = sysfs_create_link(&pci_slot->kobj, kobj, "module"); 377 if (ret) 378 dev_err(&pci_slot->bus->dev, "Error creating sysfs link (%d)\n", 379 ret); 380 kobject_put(kobj); 381 } 382 EXPORT_SYMBOL_GPL(pci_hp_create_module_link); 383 384 /** 385 * pci_hp_remove_link - remove symbolic link to the hotplug driver module. 386 * @pci_slot: struct pci_slot 387 * 388 * Helper function for pci_hotplug_core.c to remove symbolic link to 389 * the hotplug driver module. 390 */ 391 void pci_hp_remove_module_link(struct pci_slot *pci_slot) 392 { 393 sysfs_remove_link(&pci_slot->kobj, "module"); 394 } 395 EXPORT_SYMBOL_GPL(pci_hp_remove_module_link); 396 #endif 397 398 static int pci_slot_init(void) 399 { 400 struct kset *pci_bus_kset; 401 402 pci_bus_kset = bus_get_kset(&pci_bus_type); 403 pci_slots_kset = kset_create_and_add("slots", NULL, 404 &pci_bus_kset->kobj); 405 if (!pci_slots_kset) { 406 pr_err("PCI: Slot initialization failure\n"); 407 return -ENOMEM; 408 } 409 return 0; 410 } 411 412 subsys_initcall(pci_slot_init); 413