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 return sysfs_emit(buf, "%04x:%02x:%02x\n", 46 pci_domain_nr(slot->bus), 47 slot->bus->number, 48 slot->number); 49 } 50 51 static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf) 52 { 53 return sysfs_emit(buf, "%s\n", pci_speed_string(speed)); 54 } 55 56 static ssize_t max_speed_read_file(struct pci_slot *slot, char *buf) 57 { 58 return bus_speed_read(slot->bus->max_bus_speed, buf); 59 } 60 61 static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf) 62 { 63 return bus_speed_read(slot->bus->cur_bus_speed, buf); 64 } 65 66 static void pci_slot_release(struct kobject *kobj) 67 { 68 struct pci_dev *dev; 69 struct pci_slot *slot = to_pci_slot(kobj); 70 71 dev_dbg(&slot->bus->dev, "dev %02x, released physical slot %s\n", 72 slot->number, pci_slot_name(slot)); 73 74 down_read(&pci_bus_sem); 75 list_for_each_entry(dev, &slot->bus->devices, bus_list) 76 if (PCI_SLOT(dev->devfn) == slot->number) 77 dev->slot = NULL; 78 up_read(&pci_bus_sem); 79 80 list_del(&slot->list); 81 pci_bus_put(slot->bus); 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 ATTRIBUTE_GROUPS(pci_slot_default); 100 101 static const struct kobj_type pci_slot_ktype = { 102 .sysfs_ops = &pci_slot_sysfs_ops, 103 .release = &pci_slot_release, 104 .default_groups = pci_slot_default_groups, 105 }; 106 107 static char *make_slot_name(const char *name) 108 { 109 char *new_name; 110 int len, max, dup; 111 112 new_name = kstrdup(name, GFP_KERNEL); 113 if (!new_name) 114 return NULL; 115 116 /* 117 * Make sure we hit the realloc case the first time through the 118 * loop. 'len' will be strlen(name) + 3 at that point which is 119 * enough space for "name-X" and the trailing NUL. 120 */ 121 len = strlen(name) + 2; 122 max = 1; 123 dup = 1; 124 125 for (;;) { 126 struct kobject *dup_slot; 127 dup_slot = kset_find_obj(pci_slots_kset, new_name); 128 if (!dup_slot) 129 break; 130 kobject_put(dup_slot); 131 if (dup == max) { 132 len++; 133 max *= 10; 134 kfree(new_name); 135 new_name = kmalloc(len, GFP_KERNEL); 136 if (!new_name) 137 break; 138 } 139 sprintf(new_name, "%s-%d", name, dup++); 140 } 141 142 return new_name; 143 } 144 145 static int rename_slot(struct pci_slot *slot, const char *name) 146 { 147 int result = 0; 148 char *slot_name; 149 150 if (strcmp(pci_slot_name(slot), name) == 0) 151 return result; 152 153 slot_name = make_slot_name(name); 154 if (!slot_name) 155 return -ENOMEM; 156 157 result = kobject_rename(&slot->kobj, slot_name); 158 kfree(slot_name); 159 160 return result; 161 } 162 163 void pci_dev_assign_slot(struct pci_dev *dev) 164 { 165 struct pci_slot *slot; 166 167 mutex_lock(&pci_slot_mutex); 168 list_for_each_entry(slot, &dev->bus->slots, list) 169 if (PCI_SLOT(dev->devfn) == slot->number) 170 dev->slot = slot; 171 mutex_unlock(&pci_slot_mutex); 172 } 173 174 static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr) 175 { 176 struct pci_slot *slot; 177 178 /* We already hold pci_slot_mutex */ 179 list_for_each_entry(slot, &parent->slots, list) 180 if (slot->number == slot_nr) { 181 kobject_get(&slot->kobj); 182 return slot; 183 } 184 185 return NULL; 186 } 187 188 /** 189 * pci_create_slot - create or increment refcount for physical PCI slot 190 * @parent: struct pci_bus of parent bridge 191 * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder 192 * @name: user visible string presented in /sys/bus/pci/slots/<name> 193 * @hotplug: set if caller is hotplug driver, NULL otherwise 194 * 195 * PCI slots have first class attributes such as address, speed, width, 196 * and a &struct pci_slot is used to manage them. This interface will 197 * either return a new &struct pci_slot to the caller, or if the pci_slot 198 * already exists, its refcount will be incremented. 199 * 200 * Slots are uniquely identified by a @pci_bus, @slot_nr tuple. 201 * 202 * There are known platforms with broken firmware that assign the same 203 * name to multiple slots. Workaround these broken platforms by renaming 204 * the slots on behalf of the caller. If firmware assigns name N to 205 * multiple slots: 206 * 207 * The first slot is assigned N 208 * The second slot is assigned N-1 209 * The third slot is assigned N-2 210 * etc. 211 * 212 * Placeholder slots: 213 * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify 214 * a slot. There is one notable exception - pSeries (rpaphp), where the 215 * @slot_nr cannot be determined until a device is actually inserted into 216 * the slot. In this scenario, the caller may pass -1 for @slot_nr. 217 * 218 * The following semantics are imposed when the caller passes @slot_nr == 219 * -1. First, we no longer check for an existing %struct pci_slot, as there 220 * may be many slots with @slot_nr of -1. The other change in semantics is 221 * user-visible, which is the 'address' parameter presented in sysfs will 222 * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the 223 * %struct pci_bus and bb is the bus number. In other words, the devfn of 224 * the 'placeholder' slot will not be displayed. 225 */ 226 struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr, 227 const char *name, 228 struct hotplug_slot *hotplug) 229 { 230 struct pci_dev *dev; 231 struct pci_slot *slot; 232 int err = 0; 233 char *slot_name = NULL; 234 235 mutex_lock(&pci_slot_mutex); 236 237 if (slot_nr == -1) 238 goto placeholder; 239 240 /* 241 * Hotplug drivers are allowed to rename an existing slot, 242 * but only if not already claimed. 243 */ 244 slot = get_slot(parent, slot_nr); 245 if (slot) { 246 if (hotplug) { 247 if (slot->hotplug) { 248 err = -EBUSY; 249 goto put_slot; 250 } 251 err = rename_slot(slot, name); 252 if (err) 253 goto put_slot; 254 } 255 goto out; 256 } 257 258 placeholder: 259 slot = kzalloc(sizeof(*slot), GFP_KERNEL); 260 if (!slot) { 261 err = -ENOMEM; 262 goto err; 263 } 264 265 slot->bus = pci_bus_get(parent); 266 slot->number = slot_nr; 267 268 slot->kobj.kset = pci_slots_kset; 269 270 slot_name = make_slot_name(name); 271 if (!slot_name) { 272 err = -ENOMEM; 273 pci_bus_put(slot->bus); 274 kfree(slot); 275 goto err; 276 } 277 278 INIT_LIST_HEAD(&slot->list); 279 list_add(&slot->list, &parent->slots); 280 281 err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL, 282 "%s", slot_name); 283 if (err) 284 goto put_slot; 285 286 down_read(&pci_bus_sem); 287 list_for_each_entry(dev, &parent->devices, bus_list) 288 if (PCI_SLOT(dev->devfn) == slot_nr) 289 dev->slot = slot; 290 up_read(&pci_bus_sem); 291 292 dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n", 293 slot_nr, pci_slot_name(slot)); 294 295 out: 296 kfree(slot_name); 297 mutex_unlock(&pci_slot_mutex); 298 return slot; 299 300 put_slot: 301 kobject_put(&slot->kobj); 302 err: 303 slot = ERR_PTR(err); 304 goto out; 305 } 306 EXPORT_SYMBOL_GPL(pci_create_slot); 307 308 /** 309 * pci_destroy_slot - decrement refcount for physical PCI slot 310 * @slot: struct pci_slot to decrement 311 * 312 * %struct pci_slot is refcounted, so destroying them is really easy; we 313 * just call kobject_put on its kobj and let our release methods do the 314 * rest. 315 */ 316 void pci_destroy_slot(struct pci_slot *slot) 317 { 318 dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n", 319 slot->number, kref_read(&slot->kobj.kref) - 1); 320 321 mutex_lock(&pci_slot_mutex); 322 kobject_put(&slot->kobj); 323 mutex_unlock(&pci_slot_mutex); 324 } 325 EXPORT_SYMBOL_GPL(pci_destroy_slot); 326 327 static int pci_slot_init(void) 328 { 329 struct kset *pci_bus_kset; 330 331 pci_bus_kset = bus_get_kset(&pci_bus_type); 332 pci_slots_kset = kset_create_and_add("slots", NULL, 333 &pci_bus_kset->kobj); 334 if (!pci_slots_kset) { 335 pr_err("PCI: Slot initialization failure\n"); 336 return -ENOMEM; 337 } 338 return 0; 339 } 340 341 subsys_initcall(pci_slot_init); 342