drivers/pci/slot.c

   1 /*
   2  * drivers/pci/slot.c
   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/pci.h>
  10 #include <linux/err.h>
  11 #include "pci.h"
  12
  13 struct kset *pci_slots_kset;
  14 EXPORT_SYMBOL_GPL(pci_slots_kset);
  15
  16 static ssize_t pci_slot_attr_show(struct kobject *kobj,
  17                                         struct attribute *attr, char *buf)
  18 {
  19         struct pci_slot *slot = to_pci_slot(kobj);
  20         struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);
  21         return attribute->show ? attribute->show(slot, buf) : -EIO;
  22 }
  23
  24 static ssize_t pci_slot_attr_store(struct kobject *kobj,
  25                         struct attribute *attr, const char *buf, size_t len)
  26 {
  27         struct pci_slot *slot = to_pci_slot(kobj);
  28         struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);
  29         return attribute->store ? attribute->store(slot, buf, len) : -EIO;
  30 }
  31
  32 static const struct sysfs_ops pci_slot_sysfs_ops = {
  33         .show = pci_slot_attr_show,
  34         .store = pci_slot_attr_store,
  35 };
  36
  37 static ssize_t address_read_file(struct pci_slot *slot, char *buf)
  38 {
  39         if (slot->number == 0xff)
  40                 return sprintf(buf, "%04x:%02x\n",
  41                                 pci_domain_nr(slot->bus),
  42                                 slot->bus->number);
  43         else
  44                 return sprintf(buf, "%04x:%02x:%02x\n",
  45                                 pci_domain_nr(slot->bus),
  46                                 slot->bus->number,
  47                                 slot->number);
  48 }
  49
  50 /* these strings match up with the values in pci_bus_speed */
  51 static char *pci_bus_speed_strings[] = {
  52         "33 MHz PCI",           /* 0x00 */
  53         "66 MHz PCI",           /* 0x01 */
  54         "66 MHz PCI-X",         /* 0x02 */
  55         "100 MHz PCI-X",        /* 0x03 */
  56         "133 MHz PCI-X",        /* 0x04 */
  57         NULL,                   /* 0x05 */
  58         NULL,                   /* 0x06 */
  59         NULL,                   /* 0x07 */
  60         NULL,                   /* 0x08 */
  61         "66 MHz PCI-X 266",     /* 0x09 */
  62         "100 MHz PCI-X 266",    /* 0x0a */
  63         "133 MHz PCI-X 266",    /* 0x0b */
  64         "Unknown AGP",          /* 0x0c */
  65         "1x AGP",               /* 0x0d */
  66         "2x AGP",               /* 0x0e */
  67         "4x AGP",               /* 0x0f */
  68         "8x AGP",               /* 0x10 */
  69         "66 MHz PCI-X 533",     /* 0x11 */
  70         "100 MHz PCI-X 533",    /* 0x12 */
  71         "133 MHz PCI-X 533",    /* 0x13 */
  72         "2.5 GT/s PCIe",        /* 0x14 */
  73         "5.0 GT/s PCIe",        /* 0x15 */
  74         "8.0 GT/s PCIe",        /* 0x16 */
  75 };
  76
  77 static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf)
  78 {
  79         const char *speed_string;
  80
  81         if (speed < ARRAY_SIZE(pci_bus_speed_strings))
  82                 speed_string = pci_bus_speed_strings[speed];
  83         else
  84                 speed_string = "Unknown";
  85
  86         return sprintf(buf, "%s\n", speed_string);
  87 }
  88
  89 static ssize_t max_speed_read_file(struct pci_slot *slot, char *buf)
  90 {
  91         return bus_speed_read(slot->bus->max_bus_speed, buf);
  92 }
  93
  94 static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf)
  95 {
  96         return bus_speed_read(slot->bus->cur_bus_speed, buf);
  97 }
  98
  99 static void pci_slot_release(struct kobject *kobj)
 100 {
 101         struct pci_dev *dev;
 102         struct pci_slot *slot = to_pci_slot(kobj);
 103
 104         dev_dbg(&slot->bus->dev, "dev %02x, released physical slot %s\n",
 105                 slot->number, pci_slot_name(slot));
 106
 107         list_for_each_entry(dev, &slot->bus->devices, bus_list)
 108                 if (PCI_SLOT(dev->devfn) == slot->number)
 109                         dev->slot = NULL;
 110
 111         list_del(&slot->list);
 112
 113         kfree(slot);
 114 }
 115
 116 static struct pci_slot_attribute pci_slot_attr_address =
 117         __ATTR(address, (S_IFREG | S_IRUGO), address_read_file, NULL);
 118 static struct pci_slot_attribute pci_slot_attr_max_speed =
 119         __ATTR(max_bus_speed, (S_IFREG | S_IRUGO), max_speed_read_file, NULL);
 120 static struct pci_slot_attribute pci_slot_attr_cur_speed =
 121         __ATTR(cur_bus_speed, (S_IFREG | S_IRUGO), cur_speed_read_file, NULL);
 122
 123 static struct attribute *pci_slot_default_attrs[] = {
 124         &pci_slot_attr_address.attr,
 125         &pci_slot_attr_max_speed.attr,
 126         &pci_slot_attr_cur_speed.attr,
 127         NULL,
 128 };
 129
 130 static struct kobj_type pci_slot_ktype = {
 131         .sysfs_ops = &pci_slot_sysfs_ops,
 132         .release = &pci_slot_release,
 133         .default_attrs = pci_slot_default_attrs,
 134 };
 135
 136 static char *make_slot_name(const char *name)
 137 {
 138         char *new_name;
 139         int len, max, dup;
 140
 141         new_name = kstrdup(name, GFP_KERNEL);
 142         if (!new_name)
 143                 return NULL;
 144
 145         /*
 146          * Make sure we hit the realloc case the first time through the
 147          * loop.  'len' will be strlen(name) + 3 at that point which is
 148          * enough space for "name-X" and the trailing NUL.
 149          */
 150         len = strlen(name) + 2;
 151         max = 1;
 152         dup = 1;
 153
 154         for (;;) {
 155                 struct kobject *dup_slot;
 156                 dup_slot = kset_find_obj(pci_slots_kset, new_name);
 157                 if (!dup_slot)
 158                         break;
 159                 kobject_put(dup_slot);
 160                 if (dup == max) {
 161                         len++;
 162                         max *= 10;
 163                         kfree(new_name);
 164                         new_name = kmalloc(len, GFP_KERNEL);
 165                         if (!new_name)
 166                                 break;
 167                 }
 168                 sprintf(new_name, "%s-%d", name, dup++);
 169         }
 170
 171         return new_name;
 172 }
 173
 174 static int rename_slot(struct pci_slot *slot, const char *name)
 175 {
 176         int result = 0;
 177         char *slot_name;
 178
 179         if (strcmp(pci_slot_name(slot), name) == 0)
 180                 return result;
 181
 182         slot_name = make_slot_name(name);
 183         if (!slot_name)
 184                 return -ENOMEM;
 185
 186         result = kobject_rename(&slot->kobj, slot_name);
 187         kfree(slot_name);
 188
 189         return result;
 190 }
 191
 192 static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr)
 193 {
 194         struct pci_slot *slot;
 195         /*
 196          * We already hold pci_bus_sem so don't worry
 197          */
 198         list_for_each_entry(slot, &parent->slots, list)
 199                 if (slot->number == slot_nr) {
 200                         kobject_get(&slot->kobj);
 201                         return slot;
 202                 }
 203
 204         return NULL;
 205 }
 206
 207 /**
 208  * pci_create_slot - create or increment refcount for physical PCI slot
 209  * @parent: struct pci_bus of parent bridge
 210  * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder
 211  * @name: user visible string presented in /sys/bus/pci/slots/<name>
 212  * @hotplug: set if caller is hotplug driver, NULL otherwise
 213  *
 214  * PCI slots have first class attributes such as address, speed, width,
 215  * and a &struct pci_slot is used to manage them. This interface will
 216  * either return a new &struct pci_slot to the caller, or if the pci_slot
 217  * already exists, its refcount will be incremented.
 218  *
 219  * Slots are uniquely identified by a @pci_bus, @slot_nr tuple.
 220  *
 221  * There are known platforms with broken firmware that assign the same
 222  * name to multiple slots. Workaround these broken platforms by renaming
 223  * the slots on behalf of the caller. If firmware assigns name N to
 224  * multiple slots:
 225  *
 226  * The first slot is assigned N
 227  * The second slot is assigned N-1
 228  * The third slot is assigned N-2
 229  * etc.
 230  *
 231  * Placeholder slots:
 232  * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify
 233  * a slot. There is one notable exception - pSeries (rpaphp), where the
 234  * @slot_nr cannot be determined until a device is actually inserted into
 235  * the slot. In this scenario, the caller may pass -1 for @slot_nr.
 236  *
 237  * The following semantics are imposed when the caller passes @slot_nr ==
 238  * -1. First, we no longer check for an existing %struct pci_slot, as there
 239  * may be many slots with @slot_nr of -1.  The other change in semantics is
 240  * user-visible, which is the 'address' parameter presented in sysfs will
 241  * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the
 242  * %struct pci_bus and bb is the bus number. In other words, the devfn of
 243  * the 'placeholder' slot will not be displayed.
 244  */
 245 struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
 246                                  const char *name,
 247                                  struct hotplug_slot *hotplug)
 248 {
 249         struct pci_dev *dev;
 250         struct pci_slot *slot;
 251         int err = 0;
 252         char *slot_name = NULL;
 253
 254         down_write(&pci_bus_sem);
 255
 256         if (slot_nr == -1)
 257                 goto placeholder;
 258
 259         /*
 260          * Hotplug drivers are allowed to rename an existing slot,
 261          * but only if not already claimed.
 262          */
 263         slot = get_slot(parent, slot_nr);
 264         if (slot) {
 265                 if (hotplug) {
 266                         if ((err = slot->hotplug ? -EBUSY : 0)
 267                              || (err = rename_slot(slot, name))) {
 268                                 kobject_put(&slot->kobj);
 269                                 slot = NULL;
 270                                 goto err;
 271                         }
 272                 }
 273                 goto out;
 274         }
 275
 276 placeholder:
 277         slot = kzalloc(sizeof(*slot), GFP_KERNEL);
 278         if (!slot) {
 279                 err = -ENOMEM;
 280                 goto err;
 281         }
 282
 283         slot->bus = parent;
 284         slot->number = slot_nr;
 285
 286         slot->kobj.kset = pci_slots_kset;
 287
 288         slot_name = make_slot_name(name);
 289         if (!slot_name) {
 290                 err = -ENOMEM;
 291                 goto err;
 292         }
 293
 294         err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL,
 295                                    "%s", slot_name);
 296         if (err)
 297                 goto err;
 298
 299         INIT_LIST_HEAD(&slot->list);
 300         list_add(&slot->list, &parent->slots);
 301
 302         list_for_each_entry(dev, &parent->devices, bus_list)
 303                 if (PCI_SLOT(dev->devfn) == slot_nr)
 304                         dev->slot = slot;
 305
 306         dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n",
 307                 slot_nr, pci_slot_name(slot));
 308
 309 out:
 310         kfree(slot_name);
 311         up_write(&pci_bus_sem);
 312         return slot;
 313 err:
 314         kfree(slot);
 315         slot = ERR_PTR(err);
 316         goto out;
 317 }
 318 EXPORT_SYMBOL_GPL(pci_create_slot);
 319
 320 /**
 321  * pci_renumber_slot - update %struct pci_slot -> number
 322  * @slot: &struct pci_slot to update
 323  * @slot_nr: new number for slot
 324  *
 325  * The primary purpose of this interface is to allow callers who earlier
 326  * created a placeholder slot in pci_create_slot() by passing a -1 as
 327  * slot_nr, to update their %struct pci_slot with the correct @slot_nr.
 328  */
 329 void pci_renumber_slot(struct pci_slot *slot, int slot_nr)
 330 {
 331         struct pci_slot *tmp;
 332
 333         down_write(&pci_bus_sem);
 334
 335         list_for_each_entry(tmp, &slot->bus->slots, list) {
 336                 WARN_ON(tmp->number == slot_nr);
 337                 goto out;
 338         }
 339
 340         slot->number = slot_nr;
 341 out:
 342         up_write(&pci_bus_sem);
 343 }
 344 EXPORT_SYMBOL_GPL(pci_renumber_slot);
 345
 346 /**
 347  * pci_destroy_slot - decrement refcount for physical PCI slot
 348  * @slot: struct pci_slot to decrement
 349  *
 350  * %struct pci_slot is refcounted, so destroying them is really easy; we
 351  * just call kobject_put on its kobj and let our release methods do the
 352  * rest.
 353  */
 354 void pci_destroy_slot(struct pci_slot *slot)
 355 {
 356         dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n",
 357                 slot->number, atomic_read(&slot->kobj.kref.refcount) - 1);
 358
 359         down_write(&pci_bus_sem);
 360         kobject_put(&slot->kobj);
 361         up_write(&pci_bus_sem);
 362 }
 363 EXPORT_SYMBOL_GPL(pci_destroy_slot);
 364
 365 #if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE)
 366 #include <linux/pci_hotplug.h>
 367 /**
 368  * pci_hp_create_link - create symbolic link to the hotplug driver module.
 369  * @pci_slot: struct pci_slot
 370  *
 371  * Helper function for pci_hotplug_core.c to create symbolic link to
 372  * the hotplug driver module.
 373  */
 374 void pci_hp_create_module_link(struct pci_slot *pci_slot)
 375 {
 376         struct hotplug_slot *slot = pci_slot->hotplug;
 377         struct kobject *kobj = NULL;
 378         int no_warn;
 379
 380         if (!slot || !slot->ops)
 381                 return;
 382         kobj = kset_find_obj(module_kset, slot->ops->mod_name);
 383         if (!kobj)
 384                 return;
 385         no_warn = sysfs_create_link(&pci_slot->kobj, kobj, "module");
 386         kobject_put(kobj);
 387 }
 388 EXPORT_SYMBOL_GPL(pci_hp_create_module_link);
 389
 390 /**
 391  * pci_hp_remove_link - remove symbolic link to the hotplug driver module.
 392  * @pci_slot: struct pci_slot
 393  *
 394  * Helper function for pci_hotplug_core.c to remove symbolic link to
 395  * the hotplug driver module.
 396  */
 397 void pci_hp_remove_module_link(struct pci_slot *pci_slot)
 398 {
 399         sysfs_remove_link(&pci_slot->kobj, "module");
 400 }
 401 EXPORT_SYMBOL_GPL(pci_hp_remove_module_link);
 402 #endif
 403
 404 static int pci_slot_init(void)
 405 {
 406         struct kset *pci_bus_kset;
 407
 408         pci_bus_kset = bus_get_kset(&pci_bus_type);
 409         pci_slots_kset = kset_create_and_add("slots", NULL,
 410                                                 &pci_bus_kset->kobj);
 411         if (!pci_slots_kset) {
 412                 printk(KERN_ERR "PCI: Slot initialization failure\n");
 413                 return -ENOMEM;
 414         }
 415         return 0;
 416 }
 417
 418 subsys_initcall(pci_slot_init);