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 static DEFINE_MUTEX(pci_slot_mutex); 18 19 static ssize_t pci_slot_attr_show(struct kobject *kobj, 20 struct attribute *attr, char *buf) 21 { 22 struct pci_slot *slot = to_pci_slot(kobj); 23 struct pci_slot_attribute *attribute = to_pci_slot_attr(attr); 24 return attribute->show ? attribute->show(slot, buf) : -EIO; 25 } 26 27 static ssize_t pci_slot_attr_store(struct kobject *kobj, 28 struct attribute *attr, const char *buf, size_t len) 29 { 30 struct pci_slot *slot = to_pci_slot(kobj); 31 struct pci_slot_attribute *attribute = to_pci_slot_attr(attr); 32 return attribute->store ? attribute->store(slot, buf, len) : -EIO; 33 } 34 35 static const struct sysfs_ops pci_slot_sysfs_ops = { 36 .show = pci_slot_attr_show, 37 .store = pci_slot_attr_store, 38 }; 39 40 static ssize_t address_read_file(struct pci_slot *slot, char *buf) 41 { 42 if (slot->number == 0xff) 43 return sprintf(buf, "%04x:%02x\n", 44 pci_domain_nr(slot->bus), 45 slot->bus->number); 46 else 47 return sprintf(buf, "%04x:%02x:%02x\n", 48 pci_domain_nr(slot->bus), 49 slot->bus->number, 50 slot->number); 51 } 52 53 /* these strings match up with the values in pci_bus_speed */ 54 static const char *pci_bus_speed_strings[] = { 55 "33 MHz PCI", /* 0x00 */ 56 "66 MHz PCI", /* 0x01 */ 57 "66 MHz PCI-X", /* 0x02 */ 58 "100 MHz PCI-X", /* 0x03 */ 59 "133 MHz PCI-X", /* 0x04 */ 60 NULL, /* 0x05 */ 61 NULL, /* 0x06 */ 62 NULL, /* 0x07 */ 63 NULL, /* 0x08 */ 64 "66 MHz PCI-X 266", /* 0x09 */ 65 "100 MHz PCI-X 266", /* 0x0a */ 66 "133 MHz PCI-X 266", /* 0x0b */ 67 "Unknown AGP", /* 0x0c */ 68 "1x AGP", /* 0x0d */ 69 "2x AGP", /* 0x0e */ 70 "4x AGP", /* 0x0f */ 71 "8x AGP", /* 0x10 */ 72 "66 MHz PCI-X 533", /* 0x11 */ 73 "100 MHz PCI-X 533", /* 0x12 */ 74 "133 MHz PCI-X 533", /* 0x13 */ 75 "2.5 GT/s PCIe", /* 0x14 */ 76 "5.0 GT/s PCIe", /* 0x15 */ 77 "8.0 GT/s PCIe", /* 0x16 */ 78 "16.0 GT/s PCIe", /* 0x17 */ 79 }; 80 81 static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf) 82 { 83 const char *speed_string; 84 85 if (speed < ARRAY_SIZE(pci_bus_speed_strings)) 86 speed_string = pci_bus_speed_strings[speed]; 87 else 88 speed_string = "Unknown"; 89 90 return sprintf(buf, "%s\n", speed_string); 91 } 92 93 static ssize_t max_speed_read_file(struct pci_slot *slot, char *buf) 94 { 95 return bus_speed_read(slot->bus->max_bus_speed, buf); 96 } 97 98 static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf) 99 { 100 return bus_speed_read(slot->bus->cur_bus_speed, buf); 101 } 102 103 static void pci_slot_release(struct kobject *kobj) 104 { 105 struct pci_dev *dev; 106 struct pci_slot *slot = to_pci_slot(kobj); 107 108 dev_dbg(&slot->bus->dev, "dev %02x, released physical slot %s\n", 109 slot->number, pci_slot_name(slot)); 110 111 down_read(&pci_bus_sem); 112 list_for_each_entry(dev, &slot->bus->devices, bus_list) 113 if (PCI_SLOT(dev->devfn) == slot->number) 114 dev->slot = NULL; 115 up_read(&pci_bus_sem); 116 117 list_del(&slot->list); 118 119 kfree(slot); 120 } 121 122 static struct pci_slot_attribute pci_slot_attr_address = 123 __ATTR(address, S_IRUGO, address_read_file, NULL); 124 static struct pci_slot_attribute pci_slot_attr_max_speed = 125 __ATTR(max_bus_speed, S_IRUGO, max_speed_read_file, NULL); 126 static struct pci_slot_attribute pci_slot_attr_cur_speed = 127 __ATTR(cur_bus_speed, S_IRUGO, cur_speed_read_file, NULL); 128 129 static struct attribute *pci_slot_default_attrs[] = { 130 &pci_slot_attr_address.attr, 131 &pci_slot_attr_max_speed.attr, 132 &pci_slot_attr_cur_speed.attr, 133 NULL, 134 }; 135 136 static struct kobj_type pci_slot_ktype = { 137 .sysfs_ops = &pci_slot_sysfs_ops, 138 .release = &pci_slot_release, 139 .default_attrs = pci_slot_default_attrs, 140 }; 141 142 static char *make_slot_name(const char *name) 143 { 144 char *new_name; 145 int len, max, dup; 146 147 new_name = kstrdup(name, GFP_KERNEL); 148 if (!new_name) 149 return NULL; 150 151 /* 152 * Make sure we hit the realloc case the first time through the 153 * loop. 'len' will be strlen(name) + 3 at that point which is 154 * enough space for "name-X" and the trailing NUL. 155 */ 156 len = strlen(name) + 2; 157 max = 1; 158 dup = 1; 159 160 for (;;) { 161 struct kobject *dup_slot; 162 dup_slot = kset_find_obj(pci_slots_kset, new_name); 163 if (!dup_slot) 164 break; 165 kobject_put(dup_slot); 166 if (dup == max) { 167 len++; 168 max *= 10; 169 kfree(new_name); 170 new_name = kmalloc(len, GFP_KERNEL); 171 if (!new_name) 172 break; 173 } 174 sprintf(new_name, "%s-%d", name, dup++); 175 } 176 177 return new_name; 178 } 179 180 static int rename_slot(struct pci_slot *slot, const char *name) 181 { 182 int result = 0; 183 char *slot_name; 184 185 if (strcmp(pci_slot_name(slot), name) == 0) 186 return result; 187 188 slot_name = make_slot_name(name); 189 if (!slot_name) 190 return -ENOMEM; 191 192 result = kobject_rename(&slot->kobj, slot_name); 193 kfree(slot_name); 194 195 return result; 196 } 197 198 void pci_dev_assign_slot(struct pci_dev *dev) 199 { 200 struct pci_slot *slot; 201 202 mutex_lock(&pci_slot_mutex); 203 list_for_each_entry(slot, &dev->bus->slots, list) 204 if (PCI_SLOT(dev->devfn) == slot->number) 205 dev->slot = slot; 206 mutex_unlock(&pci_slot_mutex); 207 } 208 209 static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr) 210 { 211 struct pci_slot *slot; 212 213 /* We already hold pci_slot_mutex */ 214 list_for_each_entry(slot, &parent->slots, list) 215 if (slot->number == slot_nr) { 216 kobject_get(&slot->kobj); 217 return slot; 218 } 219 220 return NULL; 221 } 222 223 /** 224 * pci_create_slot - create or increment refcount for physical PCI slot 225 * @parent: struct pci_bus of parent bridge 226 * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder 227 * @name: user visible string presented in /sys/bus/pci/slots/<name> 228 * @hotplug: set if caller is hotplug driver, NULL otherwise 229 * 230 * PCI slots have first class attributes such as address, speed, width, 231 * and a &struct pci_slot is used to manage them. This interface will 232 * either return a new &struct pci_slot to the caller, or if the pci_slot 233 * already exists, its refcount will be incremented. 234 * 235 * Slots are uniquely identified by a @pci_bus, @slot_nr tuple. 236 * 237 * There are known platforms with broken firmware that assign the same 238 * name to multiple slots. Workaround these broken platforms by renaming 239 * the slots on behalf of the caller. If firmware assigns name N to 240 * multiple slots: 241 * 242 * The first slot is assigned N 243 * The second slot is assigned N-1 244 * The third slot is assigned N-2 245 * etc. 246 * 247 * Placeholder slots: 248 * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify 249 * a slot. There is one notable exception - pSeries (rpaphp), where the 250 * @slot_nr cannot be determined until a device is actually inserted into 251 * the slot. In this scenario, the caller may pass -1 for @slot_nr. 252 * 253 * The following semantics are imposed when the caller passes @slot_nr == 254 * -1. First, we no longer check for an existing %struct pci_slot, as there 255 * may be many slots with @slot_nr of -1. The other change in semantics is 256 * user-visible, which is the 'address' parameter presented in sysfs will 257 * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the 258 * %struct pci_bus and bb is the bus number. In other words, the devfn of 259 * the 'placeholder' slot will not be displayed. 260 */ 261 struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr, 262 const char *name, 263 struct hotplug_slot *hotplug) 264 { 265 struct pci_dev *dev; 266 struct pci_slot *slot; 267 int err = 0; 268 char *slot_name = NULL; 269 270 mutex_lock(&pci_slot_mutex); 271 272 if (slot_nr == -1) 273 goto placeholder; 274 275 /* 276 * Hotplug drivers are allowed to rename an existing slot, 277 * but only if not already claimed. 278 */ 279 slot = get_slot(parent, slot_nr); 280 if (slot) { 281 if (hotplug) { 282 if ((err = slot->hotplug ? -EBUSY : 0) 283 || (err = rename_slot(slot, name))) { 284 kobject_put(&slot->kobj); 285 slot = NULL; 286 goto err; 287 } 288 } 289 goto out; 290 } 291 292 placeholder: 293 slot = kzalloc(sizeof(*slot), GFP_KERNEL); 294 if (!slot) { 295 err = -ENOMEM; 296 goto err; 297 } 298 299 slot->bus = parent; 300 slot->number = slot_nr; 301 302 slot->kobj.kset = pci_slots_kset; 303 304 slot_name = make_slot_name(name); 305 if (!slot_name) { 306 err = -ENOMEM; 307 goto err; 308 } 309 310 err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL, 311 "%s", slot_name); 312 if (err) 313 goto err; 314 315 INIT_LIST_HEAD(&slot->list); 316 list_add(&slot->list, &parent->slots); 317 318 down_read(&pci_bus_sem); 319 list_for_each_entry(dev, &parent->devices, bus_list) 320 if (PCI_SLOT(dev->devfn) == slot_nr) 321 dev->slot = slot; 322 up_read(&pci_bus_sem); 323 324 dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n", 325 slot_nr, pci_slot_name(slot)); 326 327 out: 328 kfree(slot_name); 329 mutex_unlock(&pci_slot_mutex); 330 return slot; 331 err: 332 kfree(slot); 333 slot = ERR_PTR(err); 334 goto out; 335 } 336 EXPORT_SYMBOL_GPL(pci_create_slot); 337 338 /** 339 * pci_destroy_slot - decrement refcount for physical PCI slot 340 * @slot: struct pci_slot to decrement 341 * 342 * %struct pci_slot is refcounted, so destroying them is really easy; we 343 * just call kobject_put on its kobj and let our release methods do the 344 * rest. 345 */ 346 void pci_destroy_slot(struct pci_slot *slot) 347 { 348 dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n", 349 slot->number, kref_read(&slot->kobj.kref) - 1); 350 351 mutex_lock(&pci_slot_mutex); 352 kobject_put(&slot->kobj); 353 mutex_unlock(&pci_slot_mutex); 354 } 355 EXPORT_SYMBOL_GPL(pci_destroy_slot); 356 357 #if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE) 358 #include <linux/pci_hotplug.h> 359 /** 360 * pci_hp_create_link - create symbolic link to the hotplug driver module. 361 * @pci_slot: struct pci_slot 362 * 363 * Helper function for pci_hotplug_core.c to create symbolic link to 364 * the hotplug driver module. 365 */ 366 void pci_hp_create_module_link(struct pci_slot *pci_slot) 367 { 368 struct hotplug_slot *slot = pci_slot->hotplug; 369 struct kobject *kobj = NULL; 370 int ret; 371 372 if (!slot || !slot->ops) 373 return; 374 kobj = kset_find_obj(module_kset, slot->ops->mod_name); 375 if (!kobj) 376 return; 377 ret = sysfs_create_link(&pci_slot->kobj, kobj, "module"); 378 if (ret) 379 dev_err(&pci_slot->bus->dev, "Error creating sysfs link (%d)\n", 380 ret); 381 kobject_put(kobj); 382 } 383 EXPORT_SYMBOL_GPL(pci_hp_create_module_link); 384 385 /** 386 * pci_hp_remove_link - remove symbolic link to the hotplug driver module. 387 * @pci_slot: struct pci_slot 388 * 389 * Helper function for pci_hotplug_core.c to remove symbolic link to 390 * the hotplug driver module. 391 */ 392 void pci_hp_remove_module_link(struct pci_slot *pci_slot) 393 { 394 sysfs_remove_link(&pci_slot->kobj, "module"); 395 } 396 EXPORT_SYMBOL_GPL(pci_hp_remove_module_link); 397 #endif 398 399 static int pci_slot_init(void) 400 { 401 struct kset *pci_bus_kset; 402 403 pci_bus_kset = bus_get_kset(&pci_bus_type); 404 pci_slots_kset = kset_create_and_add("slots", NULL, 405 &pci_bus_kset->kobj); 406 if (!pci_slots_kset) { 407 printk(KERN_ERR "PCI: Slot initialization failure\n"); 408 return -ENOMEM; 409 } 410 return 0; 411 } 412 413 subsys_initcall(pci_slot_init); 414