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 const 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 const 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 } 310