linux/drivers/pci/slot.c
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   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/slab.h>
  10#include <linux/pci.h>
  11#include <linux/err.h>
  12#include "pci.h"
  13
  14struct kset *pci_slots_kset;
  15EXPORT_SYMBOL_GPL(pci_slots_kset);
  16
  17static 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
  25static 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
  33static const struct sysfs_ops pci_slot_sysfs_ops = {
  34        .show = pci_slot_attr_show,
  35        .store = pci_slot_attr_store,
  36};
  37
  38static ssize_t address_read_file(struct pci_slot *slot, char *buf)
  39{
  40        if (slot->number == 0xff)
  41                return sprintf(buf, "%04x:%02x\n",
  42                                pci_domain_nr(slot->bus),
  43                                slot->bus->number);
  44        else
  45                return sprintf(buf, "%04x:%02x:%02x\n",
  46                                pci_domain_nr(slot->bus),
  47                                slot->bus->number,
  48                                slot->number);
  49}
  50
  51/* these strings match up with the values in pci_bus_speed */
  52static const char *pci_bus_speed_strings[] = {
  53        "33 MHz PCI",           /* 0x00 */
  54        "66 MHz PCI",           /* 0x01 */
  55        "66 MHz PCI-X",         /* 0x02 */
  56        "100 MHz PCI-X",        /* 0x03 */
  57        "133 MHz PCI-X",        /* 0x04 */
  58        NULL,                   /* 0x05 */
  59        NULL,                   /* 0x06 */
  60        NULL,                   /* 0x07 */
  61        NULL,                   /* 0x08 */
  62        "66 MHz PCI-X 266",     /* 0x09 */
  63        "100 MHz PCI-X 266",    /* 0x0a */
  64        "133 MHz PCI-X 266",    /* 0x0b */
  65        "Unknown AGP",          /* 0x0c */
  66        "1x AGP",               /* 0x0d */
  67        "2x AGP",               /* 0x0e */
  68        "4x AGP",               /* 0x0f */
  69        "8x AGP",               /* 0x10 */
  70        "66 MHz PCI-X 533",     /* 0x11 */
  71        "100 MHz PCI-X 533",    /* 0x12 */
  72        "133 MHz PCI-X 533",    /* 0x13 */
  73        "2.5 GT/s PCIe",        /* 0x14 */
  74        "5.0 GT/s PCIe",        /* 0x15 */
  75        "8.0 GT/s PCIe",        /* 0x16 */
  76};
  77
  78static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf)
  79{
  80        const char *speed_string;
  81
  82        if (speed < ARRAY_SIZE(pci_bus_speed_strings))
  83                speed_string = pci_bus_speed_strings[speed];
  84        else
  85                speed_string = "Unknown";
  86
  87        return sprintf(buf, "%s\n", speed_string);
  88}
  89
  90static ssize_t max_speed_read_file(struct pci_slot *slot, char *buf)
  91{
  92        return bus_speed_read(slot->bus->max_bus_speed, buf);
  93}
  94
  95static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf)
  96{
  97        return bus_speed_read(slot->bus->cur_bus_speed, buf);
  98}
  99
 100static void pci_slot_release(struct kobject *kobj)
 101{
 102        struct pci_dev *dev;
 103        struct pci_slot *slot = to_pci_slot(kobj);
 104
 105        dev_dbg(&slot->bus->dev, "dev %02x, released physical slot %s\n",
 106                slot->number, pci_slot_name(slot));
 107
 108        list_for_each_entry(dev, &slot->bus->devices, bus_list)
 109                if (PCI_SLOT(dev->devfn) == slot->number)
 110                        dev->slot = NULL;
 111
 112        list_del(&slot->list);
 113
 114        kfree(slot);
 115}
 116
 117static struct pci_slot_attribute pci_slot_attr_address =
 118        __ATTR(address, (S_IFREG | S_IRUGO), address_read_file, NULL);
 119static struct pci_slot_attribute pci_slot_attr_max_speed =
 120        __ATTR(max_bus_speed, (S_IFREG | S_IRUGO), max_speed_read_file, NULL);
 121static struct pci_slot_attribute pci_slot_attr_cur_speed =
 122        __ATTR(cur_bus_speed, (S_IFREG | S_IRUGO), cur_speed_read_file, NULL);
 123
 124static struct attribute *pci_slot_default_attrs[] = {
 125        &pci_slot_attr_address.attr,
 126        &pci_slot_attr_max_speed.attr,
 127        &pci_slot_attr_cur_speed.attr,
 128        NULL,
 129};
 130
 131static struct kobj_type pci_slot_ktype = {
 132        .sysfs_ops = &pci_slot_sysfs_ops,
 133        .release = &pci_slot_release,
 134        .default_attrs = pci_slot_default_attrs,
 135};
 136
 137static char *make_slot_name(const char *name)
 138{
 139        char *new_name;
 140        int len, max, dup;
 141
 142        new_name = kstrdup(name, GFP_KERNEL);
 143        if (!new_name)
 144                return NULL;
 145
 146        /*
 147         * Make sure we hit the realloc case the first time through the
 148         * loop.  'len' will be strlen(name) + 3 at that point which is
 149         * enough space for "name-X" and the trailing NUL.
 150         */
 151        len = strlen(name) + 2;
 152        max = 1;
 153        dup = 1;
 154
 155        for (;;) {
 156                struct kobject *dup_slot;
 157                dup_slot = kset_find_obj(pci_slots_kset, new_name);
 158                if (!dup_slot)
 159                        break;
 160                kobject_put(dup_slot);
 161                if (dup == max) {
 162                        len++;
 163                        max *= 10;
 164                        kfree(new_name);
 165                        new_name = kmalloc(len, GFP_KERNEL);
 166                        if (!new_name)
 167                                break;
 168                }
 169                sprintf(new_name, "%s-%d", name, dup++);
 170        }
 171
 172        return new_name;
 173}
 174
 175static int rename_slot(struct pci_slot *slot, const char *name)
 176{
 177        int result = 0;
 178        char *slot_name;
 179
 180        if (strcmp(pci_slot_name(slot), name) == 0)
 181                return result;
 182
 183        slot_name = make_slot_name(name);
 184        if (!slot_name)
 185                return -ENOMEM;
 186
 187        result = kobject_rename(&slot->kobj, slot_name);
 188        kfree(slot_name);
 189
 190        return result;
 191}
 192
 193static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr)
 194{
 195        struct pci_slot *slot;
 196        /*
 197         * We already hold pci_bus_sem so don't worry
 198         */
 199        list_for_each_entry(slot, &parent->slots, list)
 200                if (slot->number == slot_nr) {
 201                        kobject_get(&slot->kobj);
 202                        return slot;
 203                }
 204
 205        return NULL;
 206}
 207
 208/**
 209 * pci_create_slot - create or increment refcount for physical PCI slot
 210 * @parent: struct pci_bus of parent bridge
 211 * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder
 212 * @name: user visible string presented in /sys/bus/pci/slots/<name>
 213 * @hotplug: set if caller is hotplug driver, NULL otherwise
 214 *
 215 * PCI slots have first class attributes such as address, speed, width,
 216 * and a &struct pci_slot is used to manage them. This interface will
 217 * either return a new &struct pci_slot to the caller, or if the pci_slot
 218 * already exists, its refcount will be incremented.
 219 *
 220 * Slots are uniquely identified by a @pci_bus, @slot_nr tuple.
 221 *
 222 * There are known platforms with broken firmware that assign the same
 223 * name to multiple slots. Workaround these broken platforms by renaming
 224 * the slots on behalf of the caller. If firmware assigns name N to
 225 * multiple slots:
 226 *
 227 * The first slot is assigned N
 228 * The second slot is assigned N-1
 229 * The third slot is assigned N-2
 230 * etc.
 231 *
 232 * Placeholder slots:
 233 * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify
 234 * a slot. There is one notable exception - pSeries (rpaphp), where the
 235 * @slot_nr cannot be determined until a device is actually inserted into
 236 * the slot. In this scenario, the caller may pass -1 for @slot_nr.
 237 *
 238 * The following semantics are imposed when the caller passes @slot_nr ==
 239 * -1. First, we no longer check for an existing %struct pci_slot, as there
 240 * may be many slots with @slot_nr of -1.  The other change in semantics is
 241 * user-visible, which is the 'address' parameter presented in sysfs will
 242 * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the
 243 * %struct pci_bus and bb is the bus number. In other words, the devfn of
 244 * the 'placeholder' slot will not be displayed.
 245 */
 246struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
 247                                 const char *name,
 248                                 struct hotplug_slot *hotplug)
 249{
 250        struct pci_dev *dev;
 251        struct pci_slot *slot;
 252        int err = 0;
 253        char *slot_name = NULL;
 254
 255        down_write(&pci_bus_sem);
 256
 257        if (slot_nr == -1)
 258                goto placeholder;
 259
 260        /*
 261         * Hotplug drivers are allowed to rename an existing slot,
 262         * but only if not already claimed.
 263         */
 264        slot = get_slot(parent, slot_nr);
 265        if (slot) {
 266                if (hotplug) {
 267                        if ((err = slot->hotplug ? -EBUSY : 0)
 268                             || (err = rename_slot(slot, name))) {
 269                                kobject_put(&slot->kobj);
 270                                slot = NULL;
 271                                goto err;
 272                        }
 273                }
 274                goto out;
 275        }
 276
 277placeholder:
 278        slot = kzalloc(sizeof(*slot), GFP_KERNEL);
 279        if (!slot) {
 280                err = -ENOMEM;
 281                goto err;
 282        }
 283
 284        slot->bus = parent;
 285        slot->number = slot_nr;
 286
 287        slot->kobj.kset = pci_slots_kset;
 288
 289        slot_name = make_slot_name(name);
 290        if (!slot_name) {
 291                err = -ENOMEM;
 292                goto err;
 293        }
 294
 295        err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL,
 296                                   "%s", slot_name);
 297        if (err)
 298                goto err;
 299
 300        INIT_LIST_HEAD(&slot->list);
 301        list_add(&slot->list, &parent->slots);
 302
 303        list_for_each_entry(dev, &parent->devices, bus_list)
 304                if (PCI_SLOT(dev->devfn) == slot_nr)
 305                        dev->slot = slot;
 306
 307        dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n",
 308                slot_nr, pci_slot_name(slot));
 309
 310out:
 311        kfree(slot_name);
 312        up_write(&pci_bus_sem);
 313        return slot;
 314err:
 315        kfree(slot);
 316        slot = ERR_PTR(err);
 317        goto out;
 318}
 319EXPORT_SYMBOL_GPL(pci_create_slot);
 320
 321/**
 322 * pci_renumber_slot - update %struct pci_slot -> number
 323 * @slot: &struct pci_slot to update
 324 * @slot_nr: new number for slot
 325 *
 326 * The primary purpose of this interface is to allow callers who earlier
 327 * created a placeholder slot in pci_create_slot() by passing a -1 as
 328 * slot_nr, to update their %struct pci_slot with the correct @slot_nr.
 329 */
 330void pci_renumber_slot(struct pci_slot *slot, int slot_nr)
 331{
 332        struct pci_slot *tmp;
 333
 334        down_write(&pci_bus_sem);
 335
 336        list_for_each_entry(tmp, &slot->bus->slots, list) {
 337                WARN_ON(tmp->number == slot_nr);
 338                goto out;
 339        }
 340
 341        slot->number = slot_nr;
 342out:
 343        up_write(&pci_bus_sem);
 344}
 345EXPORT_SYMBOL_GPL(pci_renumber_slot);
 346
 347/**
 348 * pci_destroy_slot - decrement refcount for physical PCI slot
 349 * @slot: struct pci_slot to decrement
 350 *
 351 * %struct pci_slot is refcounted, so destroying them is really easy; we
 352 * just call kobject_put on its kobj and let our release methods do the
 353 * rest.
 354 */
 355void pci_destroy_slot(struct pci_slot *slot)
 356{
 357        dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n",
 358                slot->number, atomic_read(&slot->kobj.kref.refcount) - 1);
 359
 360        down_write(&pci_bus_sem);
 361        kobject_put(&slot->kobj);
 362        up_write(&pci_bus_sem);
 363}
 364EXPORT_SYMBOL_GPL(pci_destroy_slot);
 365
 366#if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE)
 367#include <linux/pci_hotplug.h>
 368/**
 369 * pci_hp_create_link - create symbolic link to the hotplug driver module.
 370 * @pci_slot: struct pci_slot
 371 *
 372 * Helper function for pci_hotplug_core.c to create symbolic link to
 373 * the hotplug driver module.
 374 */
 375void pci_hp_create_module_link(struct pci_slot *pci_slot)
 376{
 377        struct hotplug_slot *slot = pci_slot->hotplug;
 378        struct kobject *kobj = NULL;
 379        int no_warn;
 380
 381        if (!slot || !slot->ops)
 382                return;
 383        kobj = kset_find_obj(module_kset, slot->ops->mod_name);
 384        if (!kobj)
 385                return;
 386        no_warn = sysfs_create_link(&pci_slot->kobj, kobj, "module");
 387        kobject_put(kobj);
 388}
 389EXPORT_SYMBOL_GPL(pci_hp_create_module_link);
 390
 391/**
 392 * pci_hp_remove_link - remove symbolic link to the hotplug driver module.
 393 * @pci_slot: struct pci_slot
 394 *
 395 * Helper function for pci_hotplug_core.c to remove symbolic link to
 396 * the hotplug driver module.
 397 */
 398void pci_hp_remove_module_link(struct pci_slot *pci_slot)
 399{
 400        sysfs_remove_link(&pci_slot->kobj, "module");
 401}
 402EXPORT_SYMBOL_GPL(pci_hp_remove_module_link);
 403#endif
 404
 405static int pci_slot_init(void)
 406{
 407        struct kset *pci_bus_kset;
 408
 409        pci_bus_kset = bus_get_kset(&pci_bus_type);
 410        pci_slots_kset = kset_create_and_add("slots", NULL,
 411                                                &pci_bus_kset->kobj);
 412        if (!pci_slots_kset) {
 413                printk(KERN_ERR "PCI: Slot initialization failure\n");
 414                return -ENOMEM;
 415        }
 416        return 0;
 417}
 418
 419subsys_initcall(pci_slot_init);
 420
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