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/module.h>
  11#include <linux/pci.h>
  12#include <linux/err.h>
  13#include "pci.h"
  14
  15struct kset *pci_slots_kset;
  16EXPORT_SYMBOL_GPL(pci_slots_kset);
  17
  18static 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
  26static 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
  34static const struct sysfs_ops pci_slot_sysfs_ops = {
  35        .show = pci_slot_attr_show,
  36        .store = pci_slot_attr_store,
  37};
  38
  39static 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 */
  53static 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};
  78
  79static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf)
  80{
  81        const char *speed_string;
  82
  83        if (speed < ARRAY_SIZE(pci_bus_speed_strings))
  84                speed_string = pci_bus_speed_strings[speed];
  85        else
  86                speed_string = "Unknown";
  87
  88        return sprintf(buf, "%s\n", speed_string);
  89}
  90
  91static ssize_t max_speed_read_file(struct pci_slot *slot, char *buf)
  92{
  93        return bus_speed_read(slot->bus->max_bus_speed, buf);
  94}
  95
  96static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf)
  97{
  98        return bus_speed_read(slot->bus->cur_bus_speed, buf);
  99}
 100
 101static void pci_slot_release(struct kobject *kobj)
 102{
 103        struct pci_dev *dev;
 104        struct pci_slot *slot = to_pci_slot(kobj);
 105
 106        dev_dbg(&slot->bus->dev, "dev %02x, released physical slot %s\n",
 107                slot->number, pci_slot_name(slot));
 108
 109        list_for_each_entry(dev, &slot->bus->devices, bus_list)
 110                if (PCI_SLOT(dev->devfn) == slot->number)
 111                        dev->slot = NULL;
 112
 113        list_del(&slot->list);
 114
 115        kfree(slot);
 116}
 117
 118static struct pci_slot_attribute pci_slot_attr_address =
 119        __ATTR(address, (S_IFREG | S_IRUGO), address_read_file, NULL);
 120static struct pci_slot_attribute pci_slot_attr_max_speed =
 121        __ATTR(max_bus_speed, (S_IFREG | S_IRUGO), max_speed_read_file, NULL);
 122static struct pci_slot_attribute pci_slot_attr_cur_speed =
 123        __ATTR(cur_bus_speed, (S_IFREG | S_IRUGO), cur_speed_read_file, NULL);
 124
 125static struct attribute *pci_slot_default_attrs[] = {
 126        &pci_slot_attr_address.attr,
 127        &pci_slot_attr_max_speed.attr,
 128        &pci_slot_attr_cur_speed.attr,
 129        NULL,
 130};
 131
 132static struct kobj_type pci_slot_ktype = {
 133        .sysfs_ops = &pci_slot_sysfs_ops,
 134        .release = &pci_slot_release,
 135        .default_attrs = pci_slot_default_attrs,
 136};
 137
 138static char *make_slot_name(const char *name)
 139{
 140        char *new_name;
 141        int len, max, dup;
 142
 143        new_name = kstrdup(name, GFP_KERNEL);
 144        if (!new_name)
 145                return NULL;
 146
 147        /*
 148         * Make sure we hit the realloc case the first time through the
 149         * loop.  'len' will be strlen(name) + 3 at that point which is
 150         * enough space for "name-X" and the trailing NUL.
 151         */
 152        len = strlen(name) + 2;
 153        max = 1;
 154        dup = 1;
 155
 156        for (;;) {
 157                struct kobject *dup_slot;
 158                dup_slot = kset_find_obj(pci_slots_kset, new_name);
 159                if (!dup_slot)
 160                        break;
 161                kobject_put(dup_slot);
 162                if (dup == max) {
 163                        len++;
 164                        max *= 10;
 165                        kfree(new_name);
 166                        new_name = kmalloc(len, GFP_KERNEL);
 167                        if (!new_name)
 168                                break;
 169                }
 170                sprintf(new_name, "%s-%d", name, dup++);
 171        }
 172
 173        return new_name;
 174}
 175
 176static int rename_slot(struct pci_slot *slot, const char *name)
 177{
 178        int result = 0;
 179        char *slot_name;
 180
 181        if (strcmp(pci_slot_name(slot), name) == 0)
 182                return result;
 183
 184        slot_name = make_slot_name(name);
 185        if (!slot_name)
 186                return -ENOMEM;
 187
 188        result = kobject_rename(&slot->kobj, slot_name);
 189        kfree(slot_name);
 190
 191        return result;
 192}
 193
 194static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr)
 195{
 196        struct pci_slot *slot;
 197        /*
 198         * We already hold pci_bus_sem so don't worry
 199         */
 200        list_for_each_entry(slot, &parent->slots, list)
 201                if (slot->number == slot_nr) {
 202                        kobject_get(&slot->kobj);
 203                        return slot;
 204                }
 205
 206        return NULL;
 207}
 208
 209/**
 210 * pci_create_slot - create or increment refcount for physical PCI slot
 211 * @parent: struct pci_bus of parent bridge
 212 * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder
 213 * @name: user visible string presented in /sys/bus/pci/slots/<name>
 214 * @hotplug: set if caller is hotplug driver, NULL otherwise
 215 *
 216 * PCI slots have first class attributes such as address, speed, width,
 217 * and a &struct pci_slot is used to manage them. This interface will
 218 * either return a new &struct pci_slot to the caller, or if the pci_slot
 219 * already exists, its refcount will be incremented.
 220 *
 221 * Slots are uniquely identified by a @pci_bus, @slot_nr tuple.
 222 *
 223 * There are known platforms with broken firmware that assign the same
 224 * name to multiple slots. Workaround these broken platforms by renaming
 225 * the slots on behalf of the caller. If firmware assigns name N to
 226 * multiple slots:
 227 *
 228 * The first slot is assigned N
 229 * The second slot is assigned N-1
 230 * The third slot is assigned N-2
 231 * etc.
 232 *
 233 * Placeholder slots:
 234 * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify
 235 * a slot. There is one notable exception - pSeries (rpaphp), where the
 236 * @slot_nr cannot be determined until a device is actually inserted into
 237 * the slot. In this scenario, the caller may pass -1 for @slot_nr.
 238 *
 239 * The following semantics are imposed when the caller passes @slot_nr ==
 240 * -1. First, we no longer check for an existing %struct pci_slot, as there
 241 * may be many slots with @slot_nr of -1.  The other change in semantics is
 242 * user-visible, which is the 'address' parameter presented in sysfs will
 243 * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the
 244 * %struct pci_bus and bb is the bus number. In other words, the devfn of
 245 * the 'placeholder' slot will not be displayed.
 246 */
 247struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
 248                                 const char *name,
 249                                 struct hotplug_slot *hotplug)
 250{
 251        struct pci_dev *dev;
 252        struct pci_slot *slot;
 253        int err = 0;
 254        char *slot_name = NULL;
 255
 256        down_write(&pci_bus_sem);
 257
 258        if (slot_nr == -1)
 259                goto placeholder;
 260
 261        /*
 262         * Hotplug drivers are allowed to rename an existing slot,
 263         * but only if not already claimed.
 264         */
 265        slot = get_slot(parent, slot_nr);
 266        if (slot) {
 267                if (hotplug) {
 268                        if ((err = slot->hotplug ? -EBUSY : 0)
 269                             || (err = rename_slot(slot, name))) {
 270                                kobject_put(&slot->kobj);
 271                                slot = NULL;
 272                                goto err;
 273                        }
 274                }
 275                goto out;
 276        }
 277
 278placeholder:
 279        slot = kzalloc(sizeof(*slot), GFP_KERNEL);
 280        if (!slot) {
 281                err = -ENOMEM;
 282                goto err;
 283        }
 284
 285        slot->bus = parent;
 286        slot->number = slot_nr;
 287
 288        slot->kobj.kset = pci_slots_kset;
 289
 290        slot_name = make_slot_name(name);
 291        if (!slot_name) {
 292                err = -ENOMEM;
 293                goto err;
 294        }
 295
 296        err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL,
 297                                   "%s", slot_name);
 298        if (err)
 299                goto err;
 300
 301        INIT_LIST_HEAD(&slot->list);
 302        list_add(&slot->list, &parent->slots);
 303
 304        list_for_each_entry(dev, &parent->devices, bus_list)
 305                if (PCI_SLOT(dev->devfn) == slot_nr)
 306                        dev->slot = slot;
 307
 308        dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n",
 309                slot_nr, pci_slot_name(slot));
 310
 311out:
 312        kfree(slot_name);
 313        up_write(&pci_bus_sem);
 314        return slot;
 315err:
 316        kfree(slot);
 317        slot = ERR_PTR(err);
 318        goto out;
 319}
 320EXPORT_SYMBOL_GPL(pci_create_slot);
 321
 322/**
 323 * pci_renumber_slot - update %struct pci_slot -> number
 324 * @slot: &struct pci_slot to update
 325 * @slot_nr: new number for slot
 326 *
 327 * The primary purpose of this interface is to allow callers who earlier
 328 * created a placeholder slot in pci_create_slot() by passing a -1 as
 329 * slot_nr, to update their %struct pci_slot with the correct @slot_nr.
 330 */
 331void pci_renumber_slot(struct pci_slot *slot, int slot_nr)
 332{
 333        struct pci_slot *tmp;
 334
 335        down_write(&pci_bus_sem);
 336
 337        list_for_each_entry(tmp, &slot->bus->slots, list) {
 338                WARN_ON(tmp->number == slot_nr);
 339                goto out;
 340        }
 341
 342        slot->number = slot_nr;
 343out:
 344        up_write(&pci_bus_sem);
 345}
 346EXPORT_SYMBOL_GPL(pci_renumber_slot);
 347
 348/**
 349 * pci_destroy_slot - decrement refcount for physical PCI slot
 350 * @slot: struct pci_slot to decrement
 351 *
 352 * %struct pci_slot is refcounted, so destroying them is really easy; we
 353 * just call kobject_put on its kobj and let our release methods do the
 354 * rest.
 355 */
 356void pci_destroy_slot(struct pci_slot *slot)
 357{
 358        dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n",
 359                slot->number, atomic_read(&slot->kobj.kref.refcount) - 1);
 360
 361        down_write(&pci_bus_sem);
 362        kobject_put(&slot->kobj);
 363        up_write(&pci_bus_sem);
 364}
 365EXPORT_SYMBOL_GPL(pci_destroy_slot);
 366
 367#if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE)
 368#include <linux/pci_hotplug.h>
 369/**
 370 * pci_hp_create_link - create symbolic link to the hotplug driver module.
 371 * @pci_slot: struct pci_slot
 372 *
 373 * Helper function for pci_hotplug_core.c to create symbolic link to
 374 * the hotplug driver module.
 375 */
 376void pci_hp_create_module_link(struct pci_slot *pci_slot)
 377{
 378        struct hotplug_slot *slot = pci_slot->hotplug;
 379        struct kobject *kobj = NULL;
 380        int no_warn;
 381
 382        if (!slot || !slot->ops)
 383                return;
 384        kobj = kset_find_obj(module_kset, slot->ops->mod_name);
 385        if (!kobj)
 386                return;
 387        no_warn = sysfs_create_link(&pci_slot->kobj, kobj, "module");
 388        kobject_put(kobj);
 389}
 390EXPORT_SYMBOL_GPL(pci_hp_create_module_link);
 391
 392/**
 393 * pci_hp_remove_link - remove symbolic link to the hotplug driver module.
 394 * @pci_slot: struct pci_slot
 395 *
 396 * Helper function for pci_hotplug_core.c to remove symbolic link to
 397 * the hotplug driver module.
 398 */
 399void pci_hp_remove_module_link(struct pci_slot *pci_slot)
 400{
 401        sysfs_remove_link(&pci_slot->kobj, "module");
 402}
 403EXPORT_SYMBOL_GPL(pci_hp_remove_module_link);
 404#endif
 405
 406static int pci_slot_init(void)
 407{
 408        struct kset *pci_bus_kset;
 409
 410        pci_bus_kset = bus_get_kset(&pci_bus_type);
 411        pci_slots_kset = kset_create_and_add("slots", NULL,
 412                                                &pci_bus_kset->kobj);
 413        if (!pci_slots_kset) {
 414                printk(KERN_ERR "PCI: Slot initialization failure\n");
 415                return -ENOMEM;
 416        }
 417        return 0;
 418}
 419
 420subsys_initcall(pci_slot_init);
 421
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