| 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * Export the firmware instance and label associated with a PCI device to |
| 4 | * sysfs |
| 5 | * |
| 6 | * Copyright (C) 2010 Dell Inc. |
| 7 | * by Narendra K <Narendra_K@dell.com>, |
| 8 | * Jordan Hargrave <Jordan_Hargrave@dell.com> |
| 9 | * |
| 10 | * PCI Firmware Specification Revision 3.1 section 4.6.7 (DSM for Naming a |
| 11 | * PCI or PCI Express Device Under Operating Systems) defines an instance |
| 12 | * number and string name. This code retrieves them and exports them to sysfs. |
| 13 | * If the system firmware does not provide the ACPI _DSM (Device Specific |
| 14 | * Method), then the SMBIOS type 41 instance number and string is exported to |
| 15 | * sysfs. |
| 16 | * |
| 17 | * SMBIOS defines type 41 for onboard pci devices. This code retrieves |
| 18 | * the instance number and string from the type 41 record and exports |
| 19 | * it to sysfs. |
| 20 | * |
| 21 | * Please see https://linux.dell.com/files/biosdevname/ for more |
| 22 | * information. |
| 23 | */ |
| 24 | |
| 25 | #include <linux/dmi.h> |
| 26 | #include <linux/sysfs.h> |
| 27 | #include <linux/pci.h> |
| 28 | #include <linux/pci_ids.h> |
| 29 | #include <linux/module.h> |
| 30 | #include <linux/device.h> |
| 31 | #include <linux/nls.h> |
| 32 | #include <linux/acpi.h> |
| 33 | #include <linux/pci-acpi.h> |
| 34 | #include "pci.h" |
| 35 | |
| 36 | static bool device_has_acpi_name(struct device *dev) |
| 37 | { |
| 38 | #ifdef CONFIG_ACPI |
| 39 | acpi_handle handle = ACPI_HANDLE(dev); |
| 40 | |
| 41 | if (!handle) |
| 42 | return false; |
| 43 | |
| 44 | return acpi_check_dsm(handle, &pci_acpi_dsm_guid, 0x2, |
| 45 | 1 << DSM_PCI_DEVICE_NAME); |
| 46 | #else |
| 47 | return false; |
| 48 | #endif |
| 49 | } |
| 50 | |
| 51 | #ifdef CONFIG_DMI |
| 52 | enum smbios_attr_enum { |
| 53 | SMBIOS_ATTR_NONE = 0, |
| 54 | SMBIOS_ATTR_LABEL_SHOW, |
| 55 | SMBIOS_ATTR_INSTANCE_SHOW, |
| 56 | }; |
| 57 | |
| 58 | static size_t find_smbios_instance_string(struct pci_dev *pdev, char *buf, |
| 59 | enum smbios_attr_enum attribute) |
| 60 | { |
| 61 | const struct dmi_device *dmi; |
| 62 | struct dmi_dev_onboard *donboard; |
| 63 | int domain_nr = pci_domain_nr(pdev->bus); |
| 64 | int bus = pdev->bus->number; |
| 65 | int devfn = pdev->devfn; |
| 66 | |
| 67 | dmi = NULL; |
| 68 | while ((dmi = dmi_find_device(DMI_DEV_TYPE_DEV_ONBOARD, |
| 69 | NULL, dmi)) != NULL) { |
| 70 | donboard = dmi->device_data; |
| 71 | if (donboard && donboard->segment == domain_nr && |
| 72 | donboard->bus == bus && |
| 73 | donboard->devfn == devfn) { |
| 74 | if (buf) { |
| 75 | if (attribute == SMBIOS_ATTR_INSTANCE_SHOW) |
| 76 | return sysfs_emit(buf, "%d\n", |
| 77 | donboard->instance); |
| 78 | else if (attribute == SMBIOS_ATTR_LABEL_SHOW) |
| 79 | return sysfs_emit(buf, "%s\n", |
| 80 | dmi->name); |
| 81 | } |
| 82 | return strlen(dmi->name); |
| 83 | } |
| 84 | } |
| 85 | return 0; |
| 86 | } |
| 87 | |
| 88 | static ssize_t smbios_label_show(struct device *dev, |
| 89 | struct device_attribute *attr, char *buf) |
| 90 | { |
| 91 | struct pci_dev *pdev = to_pci_dev(dev); |
| 92 | |
| 93 | return find_smbios_instance_string(pdev, buf, |
| 94 | SMBIOS_ATTR_LABEL_SHOW); |
| 95 | } |
| 96 | static struct device_attribute dev_attr_smbios_label = __ATTR(label, 0444, |
| 97 | smbios_label_show, NULL); |
| 98 | |
| 99 | static ssize_t index_show(struct device *dev, struct device_attribute *attr, |
| 100 | char *buf) |
| 101 | { |
| 102 | struct pci_dev *pdev = to_pci_dev(dev); |
| 103 | |
| 104 | return find_smbios_instance_string(pdev, buf, |
| 105 | SMBIOS_ATTR_INSTANCE_SHOW); |
| 106 | } |
| 107 | static DEVICE_ATTR_RO(index); |
| 108 | |
| 109 | static struct attribute *smbios_attrs[] = { |
| 110 | &dev_attr_smbios_label.attr, |
| 111 | &dev_attr_index.attr, |
| 112 | NULL, |
| 113 | }; |
| 114 | |
| 115 | static umode_t smbios_attr_is_visible(struct kobject *kobj, struct attribute *a, |
| 116 | int n) |
| 117 | { |
| 118 | struct device *dev = kobj_to_dev(kobj); |
| 119 | struct pci_dev *pdev = to_pci_dev(dev); |
| 120 | |
| 121 | if (device_has_acpi_name(dev)) |
| 122 | return 0; |
| 123 | |
| 124 | if (!find_smbios_instance_string(pdev, NULL, SMBIOS_ATTR_NONE)) |
| 125 | return 0; |
| 126 | |
| 127 | return a->mode; |
| 128 | } |
| 129 | |
| 130 | const struct attribute_group pci_dev_smbios_attr_group = { |
| 131 | .attrs = smbios_attrs, |
| 132 | .is_visible = smbios_attr_is_visible, |
| 133 | }; |
| 134 | #endif |
| 135 | |
| 136 | #ifdef CONFIG_ACPI |
| 137 | enum acpi_attr_enum { |
| 138 | ACPI_ATTR_LABEL_SHOW, |
| 139 | ACPI_ATTR_INDEX_SHOW, |
| 140 | }; |
| 141 | |
| 142 | static int dsm_label_utf16s_to_utf8s(union acpi_object *obj, char *buf) |
| 143 | { |
| 144 | int len; |
| 145 | |
| 146 | len = utf16s_to_utf8s((const wchar_t *)obj->buffer.pointer, |
| 147 | obj->buffer.length, |
| 148 | UTF16_LITTLE_ENDIAN, |
| 149 | buf, PAGE_SIZE - 1); |
| 150 | buf[len++] = '\n'; |
| 151 | |
| 152 | return len; |
| 153 | } |
| 154 | |
| 155 | static int dsm_get_label(struct device *dev, char *buf, |
| 156 | enum acpi_attr_enum attr) |
| 157 | { |
| 158 | acpi_handle handle = ACPI_HANDLE(dev); |
| 159 | union acpi_object *obj, *tmp; |
| 160 | int len = 0; |
| 161 | |
| 162 | if (!handle) |
| 163 | return -1; |
| 164 | |
| 165 | obj = acpi_evaluate_dsm(handle, &pci_acpi_dsm_guid, 0x2, |
| 166 | DSM_PCI_DEVICE_NAME, NULL); |
| 167 | if (!obj) |
| 168 | return -1; |
| 169 | |
| 170 | tmp = obj->package.elements; |
| 171 | if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 2 && |
| 172 | tmp[0].type == ACPI_TYPE_INTEGER && |
| 173 | (tmp[1].type == ACPI_TYPE_STRING || |
| 174 | tmp[1].type == ACPI_TYPE_BUFFER)) { |
| 175 | /* |
| 176 | * The second string element is optional even when |
| 177 | * this _DSM is implemented; when not implemented, |
| 178 | * this entry must return a null string. |
| 179 | */ |
| 180 | if (attr == ACPI_ATTR_INDEX_SHOW) { |
| 181 | len = sysfs_emit(buf, "%llu\n", tmp->integer.value); |
| 182 | } else if (attr == ACPI_ATTR_LABEL_SHOW) { |
| 183 | if (tmp[1].type == ACPI_TYPE_STRING) |
| 184 | len = sysfs_emit(buf, "%s\n", |
| 185 | tmp[1].string.pointer); |
| 186 | else if (tmp[1].type == ACPI_TYPE_BUFFER) |
| 187 | len = dsm_label_utf16s_to_utf8s(tmp + 1, buf); |
| 188 | } |
| 189 | } |
| 190 | |
| 191 | ACPI_FREE(obj); |
| 192 | |
| 193 | return len > 0 ? len : -1; |
| 194 | } |
| 195 | |
| 196 | static ssize_t label_show(struct device *dev, struct device_attribute *attr, |
| 197 | char *buf) |
| 198 | { |
| 199 | return dsm_get_label(dev, buf, ACPI_ATTR_LABEL_SHOW); |
| 200 | } |
| 201 | static DEVICE_ATTR_RO(label); |
| 202 | |
| 203 | static ssize_t acpi_index_show(struct device *dev, |
| 204 | struct device_attribute *attr, char *buf) |
| 205 | { |
| 206 | return dsm_get_label(dev, buf, ACPI_ATTR_INDEX_SHOW); |
| 207 | } |
| 208 | static DEVICE_ATTR_RO(acpi_index); |
| 209 | |
| 210 | static struct attribute *acpi_attrs[] = { |
| 211 | &dev_attr_label.attr, |
| 212 | &dev_attr_acpi_index.attr, |
| 213 | NULL, |
| 214 | }; |
| 215 | |
| 216 | static umode_t acpi_attr_is_visible(struct kobject *kobj, struct attribute *a, |
| 217 | int n) |
| 218 | { |
| 219 | struct device *dev = kobj_to_dev(kobj); |
| 220 | |
| 221 | if (!device_has_acpi_name(dev)) |
| 222 | return 0; |
| 223 | |
| 224 | return a->mode; |
| 225 | } |
| 226 | |
| 227 | const struct attribute_group pci_dev_acpi_attr_group = { |
| 228 | .attrs = acpi_attrs, |
| 229 | .is_visible = acpi_attr_is_visible, |
| 230 | }; |
| 231 | #endif |