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