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