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