linux/drivers/pci/pci-label.c
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   1/*
   2 * Purpose: Export the firmware instance and label associated with
   3 * a pci device to sysfs
   4 * Copyright (C) 2010 Dell Inc.
   5 * by Narendra K <Narendra_K@dell.com>,
   6 * Jordan Hargrave <Jordan_Hargrave@dell.com>
   7 *
   8 * PCI Firmware Specification Revision 3.1 section 4.6.7 (DSM for Naming a
   9 * PCI or PCI Express Device Under Operating Systems) defines an instance
  10 * number and string name. This code retrieves them and exports them to sysfs.
  11 * If the system firmware does not provide the ACPI _DSM (Device Specific
  12 * Method), then the SMBIOS type 41 instance number and string is exported to
  13 * sysfs.
  14 *
  15 * SMBIOS defines type 41 for onboard pci devices. This code retrieves
  16 * the instance number and string from the type 41 record and exports
  17 * it to sysfs.
  18 *
  19 * Please see http://linux.dell.com/wiki/index.php/Oss/libnetdevname for more
  20 * information.
  21 */
  22
  23#include <linux/dmi.h>
  24#include <linux/sysfs.h>
  25#include <linux/pci.h>
  26#include <linux/pci_ids.h>
  27#include <linux/module.h>
  28#include <linux/device.h>
  29#include <linux/nls.h>
  30#include <linux/acpi.h>
  31#include <linux/pci-acpi.h>
  32#include <acpi/acpi_bus.h>
  33#include "pci.h"
  34
  35#define DEVICE_LABEL_DSM        0x07
  36
  37#ifndef CONFIG_DMI
  38
  39static inline int
  40pci_create_smbiosname_file(struct pci_dev *pdev)
  41{
  42        return -1;
  43}
  44
  45static inline void
  46pci_remove_smbiosname_file(struct pci_dev *pdev)
  47{
  48}
  49
  50#else
  51
  52enum smbios_attr_enum {
  53        SMBIOS_ATTR_NONE = 0,
  54        SMBIOS_ATTR_LABEL_SHOW,
  55        SMBIOS_ATTR_INSTANCE_SHOW,
  56};
  57
  58static size_t
  59find_smbios_instance_string(struct pci_dev *pdev, char *buf,
  60                            enum smbios_attr_enum attribute)
  61{
  62        const struct dmi_device *dmi;
  63        struct dmi_dev_onboard *donboard;
  64        int bus;
  65        int devfn;
  66
  67        bus = pdev->bus->number;
  68        devfn = pdev->devfn;
  69
  70        dmi = NULL;
  71        while ((dmi = dmi_find_device(DMI_DEV_TYPE_DEV_ONBOARD,
  72                                      NULL, dmi)) != NULL) {
  73                donboard = dmi->device_data;
  74                if (donboard && donboard->bus == bus &&
  75                                        donboard->devfn == devfn) {
  76                        if (buf) {
  77                                if (attribute == SMBIOS_ATTR_INSTANCE_SHOW)
  78                                        return scnprintf(buf, PAGE_SIZE,
  79                                                         "%d\n",
  80                                                         donboard->instance);
  81                                else if (attribute == SMBIOS_ATTR_LABEL_SHOW)
  82                                        return scnprintf(buf, PAGE_SIZE,
  83                                                         "%s\n",
  84                                                         dmi->name);
  85                        }
  86                        return strlen(dmi->name);
  87                }
  88        }
  89        return 0;
  90}
  91
  92static umode_t
  93smbios_instance_string_exist(struct kobject *kobj, struct attribute *attr,
  94                             int n)
  95{
  96        struct device *dev;
  97        struct pci_dev *pdev;
  98
  99        dev = container_of(kobj, struct device, kobj);
 100        pdev = to_pci_dev(dev);
 101
 102        return find_smbios_instance_string(pdev, NULL, SMBIOS_ATTR_NONE) ?
 103                                           S_IRUGO : 0;
 104}
 105
 106static ssize_t
 107smbioslabel_show(struct device *dev, struct device_attribute *attr, char *buf)
 108{
 109        struct pci_dev *pdev;
 110        pdev = to_pci_dev(dev);
 111
 112        return find_smbios_instance_string(pdev, buf,
 113                                           SMBIOS_ATTR_LABEL_SHOW);
 114}
 115
 116static ssize_t
 117smbiosinstance_show(struct device *dev,
 118                    struct device_attribute *attr, char *buf)
 119{
 120        struct pci_dev *pdev;
 121        pdev = to_pci_dev(dev);
 122
 123        return find_smbios_instance_string(pdev, buf,
 124                                           SMBIOS_ATTR_INSTANCE_SHOW);
 125}
 126
 127static struct device_attribute smbios_attr_label = {
 128        .attr = {.name = "label", .mode = 0444},
 129        .show = smbioslabel_show,
 130};
 131
 132static struct device_attribute smbios_attr_instance = {
 133        .attr = {.name = "index", .mode = 0444},
 134        .show = smbiosinstance_show,
 135};
 136
 137static struct attribute *smbios_attributes[] = {
 138        &smbios_attr_label.attr,
 139        &smbios_attr_instance.attr,
 140        NULL,
 141};
 142
 143static struct attribute_group smbios_attr_group = {
 144        .attrs = smbios_attributes,
 145        .is_visible = smbios_instance_string_exist,
 146};
 147
 148static int
 149pci_create_smbiosname_file(struct pci_dev *pdev)
 150{
 151        return sysfs_create_group(&pdev->dev.kobj, &smbios_attr_group);
 152}
 153
 154static void
 155pci_remove_smbiosname_file(struct pci_dev *pdev)
 156{
 157        sysfs_remove_group(&pdev->dev.kobj, &smbios_attr_group);
 158}
 159
 160#endif
 161
 162#ifndef CONFIG_ACPI
 163
 164static inline int
 165pci_create_acpi_index_label_files(struct pci_dev *pdev)
 166{
 167        return -1;
 168}
 169
 170static inline int
 171pci_remove_acpi_index_label_files(struct pci_dev *pdev)
 172{
 173        return -1;
 174}
 175
 176static inline bool
 177device_has_dsm(struct device *dev)
 178{
 179        return false;
 180}
 181
 182#else
 183
 184static const char device_label_dsm_uuid[] = {
 185        0xD0, 0x37, 0xC9, 0xE5, 0x53, 0x35, 0x7A, 0x4D,
 186        0x91, 0x17, 0xEA, 0x4D, 0x19, 0xC3, 0x43, 0x4D
 187};
 188
 189enum acpi_attr_enum {
 190        ACPI_ATTR_NONE = 0,
 191        ACPI_ATTR_LABEL_SHOW,
 192        ACPI_ATTR_INDEX_SHOW,
 193};
 194
 195static void dsm_label_utf16s_to_utf8s(union acpi_object *obj, char *buf)
 196{
 197        int len;
 198        len = utf16s_to_utf8s((const wchar_t *)obj->
 199                              package.elements[1].string.pointer,
 200                              obj->package.elements[1].string.length,
 201                              UTF16_LITTLE_ENDIAN,
 202                              buf, PAGE_SIZE);
 203        buf[len] = '\n';
 204}
 205
 206static int
 207dsm_get_label(acpi_handle handle, int func,
 208              struct acpi_buffer *output,
 209              char *buf, enum acpi_attr_enum attribute)
 210{
 211        struct acpi_object_list input;
 212        union acpi_object params[4];
 213        union acpi_object *obj;
 214        int len = 0;
 215
 216        int err;
 217
 218        input.count = 4;
 219        input.pointer = params;
 220        params[0].type = ACPI_TYPE_BUFFER;
 221        params[0].buffer.length = sizeof(device_label_dsm_uuid);
 222        params[0].buffer.pointer = (char *)device_label_dsm_uuid;
 223        params[1].type = ACPI_TYPE_INTEGER;
 224        params[1].integer.value = 0x02;
 225        params[2].type = ACPI_TYPE_INTEGER;
 226        params[2].integer.value = func;
 227        params[3].type = ACPI_TYPE_PACKAGE;
 228        params[3].package.count = 0;
 229        params[3].package.elements = NULL;
 230
 231        err = acpi_evaluate_object(handle, "_DSM", &input, output);
 232        if (err)
 233                return -1;
 234
 235        obj = (union acpi_object *)output->pointer;
 236
 237        switch (obj->type) {
 238        case ACPI_TYPE_PACKAGE:
 239                if (obj->package.count != 2)
 240                        break;
 241                len = obj->package.elements[0].integer.value;
 242                if (buf) {
 243                        if (attribute == ACPI_ATTR_INDEX_SHOW)
 244                                scnprintf(buf, PAGE_SIZE, "%llu\n",
 245                                obj->package.elements[0].integer.value);
 246                        else if (attribute == ACPI_ATTR_LABEL_SHOW)
 247                                dsm_label_utf16s_to_utf8s(obj, buf);
 248                        kfree(output->pointer);
 249                        return strlen(buf);
 250                }
 251                kfree(output->pointer);
 252                return len;
 253        break;
 254        default:
 255                kfree(output->pointer);
 256        }
 257        return -1;
 258}
 259
 260static bool
 261device_has_dsm(struct device *dev)
 262{
 263        acpi_handle handle;
 264        struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
 265
 266        handle = DEVICE_ACPI_HANDLE(dev);
 267
 268        if (!handle)
 269                return FALSE;
 270
 271        if (dsm_get_label(handle, DEVICE_LABEL_DSM, &output, NULL,
 272                          ACPI_ATTR_NONE) > 0)
 273                return TRUE;
 274
 275        return FALSE;
 276}
 277
 278static umode_t
 279acpi_index_string_exist(struct kobject *kobj, struct attribute *attr, int n)
 280{
 281        struct device *dev;
 282
 283        dev = container_of(kobj, struct device, kobj);
 284
 285        if (device_has_dsm(dev))
 286                return S_IRUGO;
 287
 288        return 0;
 289}
 290
 291static ssize_t
 292acpilabel_show(struct device *dev, struct device_attribute *attr, char *buf)
 293{
 294        struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
 295        acpi_handle handle;
 296        int length;
 297
 298        handle = DEVICE_ACPI_HANDLE(dev);
 299
 300        if (!handle)
 301                return -1;
 302
 303        length = dsm_get_label(handle, DEVICE_LABEL_DSM,
 304                               &output, buf, ACPI_ATTR_LABEL_SHOW);
 305
 306        if (length < 1)
 307                return -1;
 308
 309        return length;
 310}
 311
 312static ssize_t
 313acpiindex_show(struct device *dev, struct device_attribute *attr, char *buf)
 314{
 315        struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
 316        acpi_handle handle;
 317        int length;
 318
 319        handle = DEVICE_ACPI_HANDLE(dev);
 320
 321        if (!handle)
 322                return -1;
 323
 324        length = dsm_get_label(handle, DEVICE_LABEL_DSM,
 325                               &output, buf, ACPI_ATTR_INDEX_SHOW);
 326
 327        if (length < 0)
 328                return -1;
 329
 330        return length;
 331
 332}
 333
 334static struct device_attribute acpi_attr_label = {
 335        .attr = {.name = "label", .mode = 0444},
 336        .show = acpilabel_show,
 337};
 338
 339static struct device_attribute acpi_attr_index = {
 340        .attr = {.name = "acpi_index", .mode = 0444},
 341        .show = acpiindex_show,
 342};
 343
 344static struct attribute *acpi_attributes[] = {
 345        &acpi_attr_label.attr,
 346        &acpi_attr_index.attr,
 347        NULL,
 348};
 349
 350static struct attribute_group acpi_attr_group = {
 351        .attrs = acpi_attributes,
 352        .is_visible = acpi_index_string_exist,
 353};
 354
 355static int
 356pci_create_acpi_index_label_files(struct pci_dev *pdev)
 357{
 358        return sysfs_create_group(&pdev->dev.kobj, &acpi_attr_group);
 359}
 360
 361static int
 362pci_remove_acpi_index_label_files(struct pci_dev *pdev)
 363{
 364        sysfs_remove_group(&pdev->dev.kobj, &acpi_attr_group);
 365        return 0;
 366}
 367#endif
 368
 369void pci_create_firmware_label_files(struct pci_dev *pdev)
 370{
 371        if (device_has_dsm(&pdev->dev))
 372                pci_create_acpi_index_label_files(pdev);
 373        else
 374                pci_create_smbiosname_file(pdev);
 375}
 376
 377void pci_remove_firmware_label_files(struct pci_dev *pdev)
 378{
 379        if (device_has_dsm(&pdev->dev))
 380                pci_remove_acpi_index_label_files(pdev);
 381        else
 382                pci_remove_smbiosname_file(pdev);
 383}
 384
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