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 "pci.h"
  33
  34 #define DEVICE_LABEL_DSM        0x07
  35
  36 #ifdef CONFIG_DMI
  37 enum smbios_attr_enum {
  38         SMBIOS_ATTR_NONE = 0,
  39         SMBIOS_ATTR_LABEL_SHOW,
  40         SMBIOS_ATTR_INSTANCE_SHOW,
  41 };
  42
  43 static size_t
  44 find_smbios_instance_string(struct pci_dev *pdev, char *buf,
  45                             enum smbios_attr_enum attribute)
  46 {
  47         const struct dmi_device *dmi;
  48         struct dmi_dev_onboard *donboard;
  49         int bus;
  50         int devfn;
  51
  52         bus = pdev->bus->number;
  53         devfn = pdev->devfn;
  54
  55         dmi = NULL;
  56         while ((dmi = dmi_find_device(DMI_DEV_TYPE_DEV_ONBOARD,
  57                                       NULL, dmi)) != NULL) {
  58                 donboard = dmi->device_data;
  59                 if (donboard && donboard->bus == bus &&
  60                                         donboard->devfn == devfn) {
  61                         if (buf) {
  62                                 if (attribute == SMBIOS_ATTR_INSTANCE_SHOW)
  63                                         return scnprintf(buf, PAGE_SIZE,
  64                                                          "%d\n",
  65                                                          donboard->instance);
  66                                 else if (attribute == SMBIOS_ATTR_LABEL_SHOW)
  67                                         return scnprintf(buf, PAGE_SIZE,
  68                                                          "%s\n",
  69                                                          dmi->name);
  70                         }
  71                         return strlen(dmi->name);
  72                 }
  73         }
  74         return 0;
  75 }
  76
  77 static umode_t
  78 smbios_instance_string_exist(struct kobject *kobj, struct attribute *attr,
  79                              int n)
  80 {
  81         struct device *dev;
  82         struct pci_dev *pdev;
  83
  84         dev = container_of(kobj, struct device, kobj);
  85         pdev = to_pci_dev(dev);
  86
  87         return find_smbios_instance_string(pdev, NULL, SMBIOS_ATTR_NONE) ?
  88                                            S_IRUGO : 0;
  89 }
  90
  91 static ssize_t
  92 smbioslabel_show(struct device *dev, struct device_attribute *attr, char *buf)
  93 {
  94         struct pci_dev *pdev;
  95         pdev = to_pci_dev(dev);
  96
  97         return find_smbios_instance_string(pdev, buf,
  98                                            SMBIOS_ATTR_LABEL_SHOW);
  99 }
 100
 101 static ssize_t
 102 smbiosinstance_show(struct device *dev,
 103                     struct device_attribute *attr, char *buf)
 104 {
 105         struct pci_dev *pdev;
 106         pdev = to_pci_dev(dev);
 107
 108         return find_smbios_instance_string(pdev, buf,
 109                                            SMBIOS_ATTR_INSTANCE_SHOW);
 110 }
 111
 112 static struct device_attribute smbios_attr_label = {
 113         .attr = {.name = "label", .mode = 0444},
 114         .show = smbioslabel_show,
 115 };
 116
 117 static struct device_attribute smbios_attr_instance = {
 118         .attr = {.name = "index", .mode = 0444},
 119         .show = smbiosinstance_show,
 120 };
 121
 122 static struct attribute *smbios_attributes[] = {
 123         &smbios_attr_label.attr,
 124         &smbios_attr_instance.attr,
 125         NULL,
 126 };
 127
 128 static struct attribute_group smbios_attr_group = {
 129         .attrs = smbios_attributes,
 130         .is_visible = smbios_instance_string_exist,
 131 };
 132
 133 static int
 134 pci_create_smbiosname_file(struct pci_dev *pdev)
 135 {
 136         return sysfs_create_group(&pdev->dev.kobj, &smbios_attr_group);
 137 }
 138
 139 static void
 140 pci_remove_smbiosname_file(struct pci_dev *pdev)
 141 {
 142         sysfs_remove_group(&pdev->dev.kobj, &smbios_attr_group);
 143 }
 144 #else
 145 static inline int
 146 pci_create_smbiosname_file(struct pci_dev *pdev)
 147 {
 148         return -1;
 149 }
 150
 151 static inline void
 152 pci_remove_smbiosname_file(struct pci_dev *pdev)
 153 {
 154 }
 155 #endif
 156
 157 #ifdef CONFIG_ACPI
 158 static const char device_label_dsm_uuid[] = {
 159         0xD0, 0x37, 0xC9, 0xE5, 0x53, 0x35, 0x7A, 0x4D,
 160         0x91, 0x17, 0xEA, 0x4D, 0x19, 0xC3, 0x43, 0x4D
 161 };
 162
 163 enum acpi_attr_enum {
 164         ACPI_ATTR_LABEL_SHOW,
 165         ACPI_ATTR_INDEX_SHOW,
 166 };
 167
 168 static void dsm_label_utf16s_to_utf8s(union acpi_object *obj, char *buf)
 169 {
 170         int len;
 171         len = utf16s_to_utf8s((const wchar_t *)obj->string.pointer,
 172                               obj->string.length,
 173                               UTF16_LITTLE_ENDIAN,
 174                               buf, PAGE_SIZE);
 175         buf[len] = '\n';
 176 }
 177
 178 static int
 179 dsm_get_label(struct device *dev, char *buf, enum acpi_attr_enum attr)
 180 {
 181         acpi_handle handle;
 182         union acpi_object *obj, *tmp;
 183         int len = -1;
 184
 185         handle = ACPI_HANDLE(dev);
 186         if (!handle)
 187                 return -1;
 188
 189         obj = acpi_evaluate_dsm(handle, device_label_dsm_uuid, 0x2,
 190                                 DEVICE_LABEL_DSM, NULL);
 191         if (!obj)
 192                 return -1;
 193
 194         tmp = obj->package.elements;
 195         if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 2 &&
 196             tmp[0].type == ACPI_TYPE_INTEGER &&
 197             tmp[1].type == ACPI_TYPE_STRING) {
 198                 /*
 199                  * The second string element is optional even when
 200                  * this _DSM is implemented; when not implemented,
 201                  * this entry must return a null string.
 202                  */
 203                 if (attr == ACPI_ATTR_INDEX_SHOW)
 204                         scnprintf(buf, PAGE_SIZE, "%llu\n", tmp->integer.value);
 205                 else if (attr == ACPI_ATTR_LABEL_SHOW)
 206                         dsm_label_utf16s_to_utf8s(tmp + 1, buf);
 207                 len = strlen(buf) > 0 ? strlen(buf) : -1;
 208         }
 209
 210         ACPI_FREE(obj);
 211
 212         return len;
 213 }
 214
 215 static bool
 216 device_has_dsm(struct device *dev)
 217 {
 218         acpi_handle handle;
 219
 220         handle = ACPI_HANDLE(dev);
 221         if (!handle)
 222                 return false;
 223
 224         return !!acpi_check_dsm(handle, device_label_dsm_uuid, 0x2,
 225                                 1 << DEVICE_LABEL_DSM);
 226 }
 227
 228 static umode_t
 229 acpi_index_string_exist(struct kobject *kobj, struct attribute *attr, int n)
 230 {
 231         struct device *dev;
 232
 233         dev = container_of(kobj, struct device, kobj);
 234
 235         if (device_has_dsm(dev))
 236                 return S_IRUGO;
 237
 238         return 0;
 239 }
 240
 241 static ssize_t
 242 acpilabel_show(struct device *dev, struct device_attribute *attr, char *buf)
 243 {
 244         return dsm_get_label(dev, buf, ACPI_ATTR_LABEL_SHOW);
 245 }
 246
 247 static ssize_t
 248 acpiindex_show(struct device *dev, struct device_attribute *attr, char *buf)
 249 {
 250         return dsm_get_label(dev, buf, ACPI_ATTR_INDEX_SHOW);
 251 }
 252
 253 static struct device_attribute acpi_attr_label = {
 254         .attr = {.name = "label", .mode = 0444},
 255         .show = acpilabel_show,
 256 };
 257
 258 static struct device_attribute acpi_attr_index = {
 259         .attr = {.name = "acpi_index", .mode = 0444},
 260         .show = acpiindex_show,
 261 };
 262
 263 static struct attribute *acpi_attributes[] = {
 264         &acpi_attr_label.attr,
 265         &acpi_attr_index.attr,
 266         NULL,
 267 };
 268
 269 static struct attribute_group acpi_attr_group = {
 270         .attrs = acpi_attributes,
 271         .is_visible = acpi_index_string_exist,
 272 };
 273
 274 static int
 275 pci_create_acpi_index_label_files(struct pci_dev *pdev)
 276 {
 277         return sysfs_create_group(&pdev->dev.kobj, &acpi_attr_group);
 278 }
 279
 280 static int
 281 pci_remove_acpi_index_label_files(struct pci_dev *pdev)
 282 {
 283         sysfs_remove_group(&pdev->dev.kobj, &acpi_attr_group);
 284         return 0;
 285 }
 286 #else
 287 static inline int
 288 pci_create_acpi_index_label_files(struct pci_dev *pdev)
 289 {
 290         return -1;
 291 }
 292
 293 static inline int
 294 pci_remove_acpi_index_label_files(struct pci_dev *pdev)
 295 {
 296         return -1;
 297 }
 298
 299 static inline bool
 300 device_has_dsm(struct device *dev)
 301 {
 302         return false;
 303 }
 304 #endif
 305
 306 void pci_create_firmware_label_files(struct pci_dev *pdev)
 307 {
 308         if (device_has_dsm(&pdev->dev))
 309                 pci_create_acpi_index_label_files(pdev);
 310         else
 311                 pci_create_smbiosname_file(pdev);
 312 }
 313
 314 void pci_remove_firmware_label_files(struct pci_dev *pdev)
 315 {
 316         if (device_has_dsm(&pdev->dev))
 317                 pci_remove_acpi_index_label_files(pdev);
 318         else
 319                 pci_remove_smbiosname_file(pdev);
 320 }