drivers/pci/pci-label.c

   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
  39 static inline int
  40 pci_create_smbiosname_file(struct pci_dev *pdev)
  41 {
  42         return -1;
  43 }
  44
  45 static inline void
  46 pci_remove_smbiosname_file(struct pci_dev *pdev)
  47 {
  48 }
  49
  50 #else
  51
  52 enum smbios_attr_enum {
  53         SMBIOS_ATTR_NONE = 0,
  54         SMBIOS_ATTR_LABEL_SHOW,
  55         SMBIOS_ATTR_INSTANCE_SHOW,
  56 };
  57
  58 static size_t
  59 find_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
  92 static mode_t
  93 smbios_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
 106 static ssize_t
 107 smbioslabel_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
 116 static ssize_t
 117 smbiosinstance_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
 127 static struct device_attribute smbios_attr_label = {
 128         .attr = {.name = "label", .mode = 0444},
 129         .show = smbioslabel_show,
 130 };
 131
 132 static struct device_attribute smbios_attr_instance = {
 133         .attr = {.name = "index", .mode = 0444},
 134         .show = smbiosinstance_show,
 135 };
 136
 137 static struct attribute *smbios_attributes[] = {
 138         &smbios_attr_label.attr,
 139         &smbios_attr_instance.attr,
 140         NULL,
 141 };
 142
 143 static struct attribute_group smbios_attr_group = {
 144         .attrs = smbios_attributes,
 145         .is_visible = smbios_instance_string_exist,
 146 };
 147
 148 static int
 149 pci_create_smbiosname_file(struct pci_dev *pdev)
 150 {
 151         return sysfs_create_group(&pdev->dev.kobj, &smbios_attr_group);
 152 }
 153
 154 static void
 155 pci_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
 164 static inline int
 165 pci_create_acpi_index_label_files(struct pci_dev *pdev)
 166 {
 167         return -1;
 168 }
 169
 170 static inline int
 171 pci_remove_acpi_index_label_files(struct pci_dev *pdev)
 172 {
 173         return -1;
 174 }
 175
 176 static inline bool
 177 device_has_dsm(struct device *dev)
 178 {
 179         return false;
 180 }
 181
 182 #else
 183
 184 static 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
 189 enum acpi_attr_enum {
 190         ACPI_ATTR_NONE = 0,
 191         ACPI_ATTR_LABEL_SHOW,
 192         ACPI_ATTR_INDEX_SHOW,
 193 };
 194
 195 static 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
 206 static int
 207 dsm_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
 260 static bool
 261 device_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
 278 static mode_t
 279 acpi_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
 291 static ssize_t
 292 acpilabel_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
 312 static ssize_t
 313 acpiindex_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
 334 static struct device_attribute acpi_attr_label = {
 335         .attr = {.name = "label", .mode = 0444},
 336         .show = acpilabel_show,
 337 };
 338
 339 static struct device_attribute acpi_attr_index = {
 340         .attr = {.name = "acpi_index", .mode = 0444},
 341         .show = acpiindex_show,
 342 };
 343
 344 static struct attribute *acpi_attributes[] = {
 345         &acpi_attr_label.attr,
 346         &acpi_attr_index.attr,
 347         NULL,
 348 };
 349
 350 static struct attribute_group acpi_attr_group = {
 351         .attrs = acpi_attributes,
 352         .is_visible = acpi_index_string_exist,
 353 };
 354
 355 static int
 356 pci_create_acpi_index_label_files(struct pci_dev *pdev)
 357 {
 358         return sysfs_create_group(&pdev->dev.kobj, &acpi_attr_group);
 359 }
 360
 361 static int
 362 pci_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
 369 void 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
 377 void 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 }