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/module.h>
  11 #include <linux/pci.h>
  12 #include <linux/err.h>
  13 #include "pci.h"
  14
  15 struct kset *pci_slots_kset;
  16 EXPORT_SYMBOL_GPL(pci_slots_kset);
  17
  18 static 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
  26 static 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
  34 static const struct sysfs_ops pci_slot_sysfs_ops = {
  35         .show = pci_slot_attr_show,
  36         .store = pci_slot_attr_store,
  37 };
  38
  39 static 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 */
  53 static 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
  79 static 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
  91 static 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
  96 static 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
 101 static 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
 118 static struct pci_slot_attribute pci_slot_attr_address =
 119         __ATTR(address, S_IRUGO, address_read_file, NULL);
 120 static struct pci_slot_attribute pci_slot_attr_max_speed =
 121         __ATTR(max_bus_speed, S_IRUGO, max_speed_read_file, NULL);
 122 static struct pci_slot_attribute pci_slot_attr_cur_speed =
 123         __ATTR(cur_bus_speed, S_IRUGO, cur_speed_read_file, NULL);
 124
 125 static 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
 132 static 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
 138 static 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
 176 static 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
 194 static 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  */
 247 struct 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
 278 placeholder:
 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
 311 out:
 312         kfree(slot_name);
 313         up_write(&pci_bus_sem);
 314         return slot;
 315 err:
 316         kfree(slot);
 317         slot = ERR_PTR(err);
 318         goto out;
 319 }
 320 EXPORT_SYMBOL_GPL(pci_create_slot);
 321
 322 /**
 323  * pci_destroy_slot - decrement refcount for physical PCI slot
 324  * @slot: struct pci_slot to decrement
 325  *
 326  * %struct pci_slot is refcounted, so destroying them is really easy; we
 327  * just call kobject_put on its kobj and let our release methods do the
 328  * rest.
 329  */
 330 void pci_destroy_slot(struct pci_slot *slot)
 331 {
 332         dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n",
 333                 slot->number, atomic_read(&slot->kobj.kref.refcount) - 1);
 334
 335         down_write(&pci_bus_sem);
 336         kobject_put(&slot->kobj);
 337         up_write(&pci_bus_sem);
 338 }
 339 EXPORT_SYMBOL_GPL(pci_destroy_slot);
 340
 341 #if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE)
 342 #include <linux/pci_hotplug.h>
 343 /**
 344  * pci_hp_create_link - create symbolic link to the hotplug driver module.
 345  * @pci_slot: struct pci_slot
 346  *
 347  * Helper function for pci_hotplug_core.c to create symbolic link to
 348  * the hotplug driver module.
 349  */
 350 void pci_hp_create_module_link(struct pci_slot *pci_slot)
 351 {
 352         struct hotplug_slot *slot = pci_slot->hotplug;
 353         struct kobject *kobj = NULL;
 354         int ret;
 355
 356         if (!slot || !slot->ops)
 357                 return;
 358         kobj = kset_find_obj(module_kset, slot->ops->mod_name);
 359         if (!kobj)
 360                 return;
 361         ret = sysfs_create_link(&pci_slot->kobj, kobj, "module");
 362         if (ret)
 363                 dev_err(&pci_slot->bus->dev, "Error creating sysfs link (%d)\n",
 364                         ret);
 365         kobject_put(kobj);
 366 }
 367 EXPORT_SYMBOL_GPL(pci_hp_create_module_link);
 368
 369 /**
 370  * pci_hp_remove_link - remove symbolic link to the hotplug driver module.
 371  * @pci_slot: struct pci_slot
 372  *
 373  * Helper function for pci_hotplug_core.c to remove symbolic link to
 374  * the hotplug driver module.
 375  */
 376 void pci_hp_remove_module_link(struct pci_slot *pci_slot)
 377 {
 378         sysfs_remove_link(&pci_slot->kobj, "module");
 379 }
 380 EXPORT_SYMBOL_GPL(pci_hp_remove_module_link);
 381 #endif
 382
 383 static int pci_slot_init(void)
 384 {
 385         struct kset *pci_bus_kset;
 386
 387         pci_bus_kset = bus_get_kset(&pci_bus_type);
 388         pci_slots_kset = kset_create_and_add("slots", NULL,
 389                                                 &pci_bus_kset->kobj);
 390         if (!pci_slots_kset) {
 391                 printk(KERN_ERR "PCI: Slot initialization failure\n");
 392                 return -ENOMEM;
 393         }
 394         return 0;
 395 }
 396
 397 subsys_initcall(pci_slot_init);