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