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229 lines
5.6 KiB
229 lines
5.6 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Export the firmware instance and label associated with a PCI device to |
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* sysfs |
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* |
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* Copyright (C) 2010 Dell Inc. |
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* by Narendra K <[email protected]>, |
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* Jordan Hargrave <[email protected]> |
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* |
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* PCI Firmware Specification Revision 3.1 section 4.6.7 (DSM for Naming a |
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* PCI or PCI Express Device Under Operating Systems) defines an instance |
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* number and string name. This code retrieves them and exports them to sysfs. |
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* If the system firmware does not provide the ACPI _DSM (Device Specific |
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* Method), then the SMBIOS type 41 instance number and string is exported to |
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* sysfs. |
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* |
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* SMBIOS defines type 41 for onboard pci devices. This code retrieves |
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* the instance number and string from the type 41 record and exports |
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* it to sysfs. |
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* |
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* Please see https://linux.dell.com/files/biosdevname/ for more |
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* information. |
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*/ |
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#include <linux/dmi.h> |
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#include <linux/sysfs.h> |
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#include <linux/pci.h> |
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#include <linux/pci_ids.h> |
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#include <linux/module.h> |
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#include <linux/device.h> |
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#include <linux/nls.h> |
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#include <linux/acpi.h> |
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#include <linux/pci-acpi.h> |
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#include "pci.h" |
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static bool device_has_acpi_name(struct device *dev) |
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{ |
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#ifdef CONFIG_ACPI |
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acpi_handle handle = ACPI_HANDLE(dev); |
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if (!handle) |
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return false; |
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return acpi_check_dsm(handle, &pci_acpi_dsm_guid, 0x2, |
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1 << DSM_PCI_DEVICE_NAME); |
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#else |
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return false; |
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#endif |
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} |
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#ifdef CONFIG_DMI |
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enum smbios_attr_enum { |
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SMBIOS_ATTR_NONE = 0, |
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SMBIOS_ATTR_LABEL_SHOW, |
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SMBIOS_ATTR_INSTANCE_SHOW, |
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}; |
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static size_t find_smbios_instance_string(struct pci_dev *pdev, char *buf, |
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enum smbios_attr_enum attribute) |
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{ |
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const struct dmi_device *dmi; |
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struct dmi_dev_onboard *donboard; |
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int domain_nr = pci_domain_nr(pdev->bus); |
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int bus = pdev->bus->number; |
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int devfn = pdev->devfn; |
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dmi = NULL; |
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while ((dmi = dmi_find_device(DMI_DEV_TYPE_DEV_ONBOARD, |
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NULL, dmi)) != NULL) { |
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donboard = dmi->device_data; |
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if (donboard && donboard->segment == domain_nr && |
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donboard->bus == bus && |
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donboard->devfn == devfn) { |
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if (buf) { |
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if (attribute == SMBIOS_ATTR_INSTANCE_SHOW) |
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return sysfs_emit(buf, "%d\n", |
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donboard->instance); |
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else if (attribute == SMBIOS_ATTR_LABEL_SHOW) |
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return sysfs_emit(buf, "%s\n", |
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dmi->name); |
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} |
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return strlen(dmi->name); |
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} |
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} |
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return 0; |
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} |
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static ssize_t smbios_label_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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struct pci_dev *pdev = to_pci_dev(dev); |
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return find_smbios_instance_string(pdev, buf, |
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SMBIOS_ATTR_LABEL_SHOW); |
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} |
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static struct device_attribute dev_attr_smbios_label = __ATTR(label, 0444, |
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smbios_label_show, NULL); |
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static ssize_t index_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct pci_dev *pdev = to_pci_dev(dev); |
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return find_smbios_instance_string(pdev, buf, |
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SMBIOS_ATTR_INSTANCE_SHOW); |
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} |
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static DEVICE_ATTR_RO(index); |
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static struct attribute *smbios_attrs[] = { |
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&dev_attr_smbios_label.attr, |
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&dev_attr_index.attr, |
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NULL, |
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}; |
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static umode_t smbios_attr_is_visible(struct kobject *kobj, struct attribute *a, |
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int n) |
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{ |
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struct device *dev = kobj_to_dev(kobj); |
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struct pci_dev *pdev = to_pci_dev(dev); |
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if (device_has_acpi_name(dev)) |
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return 0; |
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if (!find_smbios_instance_string(pdev, NULL, SMBIOS_ATTR_NONE)) |
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return 0; |
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return a->mode; |
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} |
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const struct attribute_group pci_dev_smbios_attr_group = { |
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.attrs = smbios_attrs, |
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.is_visible = smbios_attr_is_visible, |
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}; |
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#endif |
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#ifdef CONFIG_ACPI |
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enum acpi_attr_enum { |
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ACPI_ATTR_LABEL_SHOW, |
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ACPI_ATTR_INDEX_SHOW, |
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}; |
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static void dsm_label_utf16s_to_utf8s(union acpi_object *obj, char *buf) |
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{ |
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int len; |
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len = utf16s_to_utf8s((const wchar_t *)obj->buffer.pointer, |
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obj->buffer.length, |
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UTF16_LITTLE_ENDIAN, |
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buf, PAGE_SIZE); |
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buf[len] = '\n'; |
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} |
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static int dsm_get_label(struct device *dev, char *buf, |
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enum acpi_attr_enum attr) |
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{ |
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acpi_handle handle = ACPI_HANDLE(dev); |
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union acpi_object *obj, *tmp; |
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int len = -1; |
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if (!handle) |
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return -1; |
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obj = acpi_evaluate_dsm(handle, &pci_acpi_dsm_guid, 0x2, |
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DSM_PCI_DEVICE_NAME, NULL); |
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if (!obj) |
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return -1; |
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tmp = obj->package.elements; |
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if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 2 && |
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tmp[0].type == ACPI_TYPE_INTEGER && |
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(tmp[1].type == ACPI_TYPE_STRING || |
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tmp[1].type == ACPI_TYPE_BUFFER)) { |
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/* |
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* The second string element is optional even when |
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* this _DSM is implemented; when not implemented, |
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* this entry must return a null string. |
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*/ |
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if (attr == ACPI_ATTR_INDEX_SHOW) { |
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scnprintf(buf, PAGE_SIZE, "%llu\n", tmp->integer.value); |
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} else if (attr == ACPI_ATTR_LABEL_SHOW) { |
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if (tmp[1].type == ACPI_TYPE_STRING) |
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scnprintf(buf, PAGE_SIZE, "%s\n", |
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tmp[1].string.pointer); |
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else if (tmp[1].type == ACPI_TYPE_BUFFER) |
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dsm_label_utf16s_to_utf8s(tmp + 1, buf); |
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} |
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len = strlen(buf) > 0 ? strlen(buf) : -1; |
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} |
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ACPI_FREE(obj); |
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return len; |
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} |
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static ssize_t label_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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return dsm_get_label(dev, buf, ACPI_ATTR_LABEL_SHOW); |
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} |
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static DEVICE_ATTR_RO(label); |
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static ssize_t acpi_index_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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return dsm_get_label(dev, buf, ACPI_ATTR_INDEX_SHOW); |
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} |
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static DEVICE_ATTR_RO(acpi_index); |
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static struct attribute *acpi_attrs[] = { |
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&dev_attr_label.attr, |
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&dev_attr_acpi_index.attr, |
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NULL, |
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}; |
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static umode_t acpi_attr_is_visible(struct kobject *kobj, struct attribute *a, |
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int n) |
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{ |
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struct device *dev = kobj_to_dev(kobj); |
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if (!device_has_acpi_name(dev)) |
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return 0; |
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return a->mode; |
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} |
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const struct attribute_group pci_dev_acpi_attr_group = { |
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.attrs = acpi_attrs, |
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.is_visible = acpi_attr_is_visible, |
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}; |
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#endif
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