1 // SPDX-License-Identifier: GPL-2.0
3 * Purpose: Export the firmware instance and label associated with
4 * a pci device to sysfs
5 * Copyright (C) 2010 Dell Inc.
6 * by Narendra K <Narendra_K@dell.com>,
7 * Jordan Hargrave <Jordan_Hargrave@dell.com>
9 * PCI Firmware Specification Revision 3.1 section 4.6.7 (DSM for Naming a
10 * PCI or PCI Express Device Under Operating Systems) defines an instance
11 * number and string name. This code retrieves them and exports them to sysfs.
12 * If the system firmware does not provide the ACPI _DSM (Device Specific
13 * Method), then the SMBIOS type 41 instance number and string is exported to
16 * SMBIOS defines type 41 for onboard pci devices. This code retrieves
17 * the instance number and string from the type 41 record and exports
20 * Please see http://linux.dell.com/files/biosdevname/ for more
24 #include <linux/dmi.h>
25 #include <linux/sysfs.h>
26 #include <linux/pci.h>
27 #include <linux/pci_ids.h>
28 #include <linux/module.h>
29 #include <linux/device.h>
30 #include <linux/nls.h>
31 #include <linux/acpi.h>
32 #include <linux/pci-acpi.h>
36 enum smbios_attr_enum {
38 SMBIOS_ATTR_LABEL_SHOW,
39 SMBIOS_ATTR_INSTANCE_SHOW,
42 static size_t find_smbios_instance_string(struct pci_dev *pdev, char *buf,
43 enum smbios_attr_enum attribute)
45 const struct dmi_device *dmi;
46 struct dmi_dev_onboard *donboard;
51 domain_nr = pci_domain_nr(pdev->bus);
52 bus = pdev->bus->number;
56 while ((dmi = dmi_find_device(DMI_DEV_TYPE_DEV_ONBOARD,
57 NULL, dmi)) != NULL) {
58 donboard = dmi->device_data;
59 if (donboard && donboard->segment == domain_nr &&
60 donboard->bus == bus &&
61 donboard->devfn == devfn) {
63 if (attribute == SMBIOS_ATTR_INSTANCE_SHOW)
64 return scnprintf(buf, PAGE_SIZE,
67 else if (attribute == SMBIOS_ATTR_LABEL_SHOW)
68 return scnprintf(buf, PAGE_SIZE,
72 return strlen(dmi->name);
78 static umode_t smbios_instance_string_exist(struct kobject *kobj,
79 struct attribute *attr, int n)
84 dev = kobj_to_dev(kobj);
85 pdev = to_pci_dev(dev);
87 return find_smbios_instance_string(pdev, NULL, SMBIOS_ATTR_NONE) ?
91 static ssize_t smbioslabel_show(struct device *dev,
92 struct device_attribute *attr, char *buf)
95 pdev = to_pci_dev(dev);
97 return find_smbios_instance_string(pdev, buf,
98 SMBIOS_ATTR_LABEL_SHOW);
101 static ssize_t smbiosinstance_show(struct device *dev,
102 struct device_attribute *attr, char *buf)
104 struct pci_dev *pdev;
105 pdev = to_pci_dev(dev);
107 return find_smbios_instance_string(pdev, buf,
108 SMBIOS_ATTR_INSTANCE_SHOW);
111 static struct device_attribute smbios_attr_label = {
112 .attr = {.name = "label", .mode = 0444},
113 .show = smbioslabel_show,
116 static struct device_attribute smbios_attr_instance = {
117 .attr = {.name = "index", .mode = 0444},
118 .show = smbiosinstance_show,
121 static struct attribute *smbios_attributes[] = {
122 &smbios_attr_label.attr,
123 &smbios_attr_instance.attr,
127 static const struct attribute_group smbios_attr_group = {
128 .attrs = smbios_attributes,
129 .is_visible = smbios_instance_string_exist,
132 static int pci_create_smbiosname_file(struct pci_dev *pdev)
134 return sysfs_create_group(&pdev->dev.kobj, &smbios_attr_group);
137 static void pci_remove_smbiosname_file(struct pci_dev *pdev)
139 sysfs_remove_group(&pdev->dev.kobj, &smbios_attr_group);
142 static inline int pci_create_smbiosname_file(struct pci_dev *pdev)
147 static inline void pci_remove_smbiosname_file(struct pci_dev *pdev)
153 enum acpi_attr_enum {
154 ACPI_ATTR_LABEL_SHOW,
155 ACPI_ATTR_INDEX_SHOW,
158 static void dsm_label_utf16s_to_utf8s(union acpi_object *obj, char *buf)
161 len = utf16s_to_utf8s((const wchar_t *)obj->buffer.pointer,
168 static int dsm_get_label(struct device *dev, char *buf,
169 enum acpi_attr_enum attr)
172 union acpi_object *obj, *tmp;
175 handle = ACPI_HANDLE(dev);
179 obj = acpi_evaluate_dsm(handle, &pci_acpi_dsm_guid, 0x2,
180 DEVICE_LABEL_DSM, NULL);
184 tmp = obj->package.elements;
185 if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 2 &&
186 tmp[0].type == ACPI_TYPE_INTEGER &&
187 (tmp[1].type == ACPI_TYPE_STRING ||
188 tmp[1].type == ACPI_TYPE_BUFFER)) {
190 * The second string element is optional even when
191 * this _DSM is implemented; when not implemented,
192 * this entry must return a null string.
194 if (attr == ACPI_ATTR_INDEX_SHOW) {
195 scnprintf(buf, PAGE_SIZE, "%llu\n", tmp->integer.value);
196 } else if (attr == ACPI_ATTR_LABEL_SHOW) {
197 if (tmp[1].type == ACPI_TYPE_STRING)
198 scnprintf(buf, PAGE_SIZE, "%s\n",
199 tmp[1].string.pointer);
200 else if (tmp[1].type == ACPI_TYPE_BUFFER)
201 dsm_label_utf16s_to_utf8s(tmp + 1, buf);
203 len = strlen(buf) > 0 ? strlen(buf) : -1;
211 static bool device_has_dsm(struct device *dev)
215 handle = ACPI_HANDLE(dev);
219 return !!acpi_check_dsm(handle, &pci_acpi_dsm_guid, 0x2,
220 1 << DEVICE_LABEL_DSM);
223 static umode_t acpi_index_string_exist(struct kobject *kobj,
224 struct attribute *attr, int n)
228 dev = kobj_to_dev(kobj);
230 if (device_has_dsm(dev))
236 static ssize_t acpilabel_show(struct device *dev,
237 struct device_attribute *attr, char *buf)
239 return dsm_get_label(dev, buf, ACPI_ATTR_LABEL_SHOW);
242 static ssize_t acpiindex_show(struct device *dev,
243 struct device_attribute *attr, char *buf)
245 return dsm_get_label(dev, buf, ACPI_ATTR_INDEX_SHOW);
248 static struct device_attribute acpi_attr_label = {
249 .attr = {.name = "label", .mode = 0444},
250 .show = acpilabel_show,
253 static struct device_attribute acpi_attr_index = {
254 .attr = {.name = "acpi_index", .mode = 0444},
255 .show = acpiindex_show,
258 static struct attribute *acpi_attributes[] = {
259 &acpi_attr_label.attr,
260 &acpi_attr_index.attr,
264 static const struct attribute_group acpi_attr_group = {
265 .attrs = acpi_attributes,
266 .is_visible = acpi_index_string_exist,
269 static int pci_create_acpi_index_label_files(struct pci_dev *pdev)
271 return sysfs_create_group(&pdev->dev.kobj, &acpi_attr_group);
274 static int pci_remove_acpi_index_label_files(struct pci_dev *pdev)
276 sysfs_remove_group(&pdev->dev.kobj, &acpi_attr_group);
280 static inline int pci_create_acpi_index_label_files(struct pci_dev *pdev)
285 static inline int pci_remove_acpi_index_label_files(struct pci_dev *pdev)
290 static inline bool device_has_dsm(struct device *dev)
296 void pci_create_firmware_label_files(struct pci_dev *pdev)
298 if (device_has_dsm(&pdev->dev))
299 pci_create_acpi_index_label_files(pdev);
301 pci_create_smbiosname_file(pdev);
304 void pci_remove_firmware_label_files(struct pci_dev *pdev)
306 if (device_has_dsm(&pdev->dev))
307 pci_remove_acpi_index_label_files(pdev);
309 pci_remove_smbiosname_file(pdev);