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/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 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 */
  52 static 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
  78 static 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
  90 static 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
  95 static 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
 100 static 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
 117 static struct pci_slot_attribute pci_slot_attr_address =
 118         __ATTR(address, (S_IFREG | S_IRUGO), address_read_file, NULL);
 119 static struct pci_slot_attribute pci_slot_attr_max_speed =
 120         __ATTR(max_bus_speed, (S_IFREG | S_IRUGO), max_speed_read_file, NULL);
 121 static struct pci_slot_attribute pci_slot_attr_cur_speed =
 122         __ATTR(cur_bus_speed, (S_IFREG | S_IRUGO), cur_speed_read_file, NULL);
 123
 124 static 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
 131 static 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
 137 static 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
 175 static 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
 193 static 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  */
 246 struct 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
 277 placeholder:
 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
 310 out:
 311         kfree(slot_name);
 312         up_write(&pci_bus_sem);
 313         return slot;
 314 err:
 315         kfree(slot);
 316         slot = ERR_PTR(err);
 317         goto out;
 318 }
 319 EXPORT_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  */
 330 void 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;
 342 out:
 343         up_write(&pci_bus_sem);
 344 }
 345 EXPORT_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  */
 355 void 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 }
 364 EXPORT_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  */
 375 void 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 }
 389 EXPORT_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  */
 398 void pci_hp_remove_module_link(struct pci_slot *pci_slot)
 399 {
 400         sysfs_remove_link(&pci_slot->kobj, "module");
 401 }
 402 EXPORT_SYMBOL_GPL(pci_hp_remove_module_link);
 403 #endif
 404
 405 static 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
 419 subsys_initcall(pci_slot_init);