linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * Export the firmware instance and label associated with a PCI device to

 * sysfs

 *

 * Copyright (C) 2010 Dell Inc.

 * by Narendra K <Narendra_K@dell.com>,

 * Jordan Hargrave <Jordan_Hargrave@dell.com>

 *

 * PCI Firmware Specification Revision 3.1 section 4.6.7 (DSM for Naming a

 * PCI or PCI Express Device Under Operating Systems) defines an instance

 * number and string name. This code retrieves them and exports them to sysfs.

 * If the system firmware does not provide the ACPI _DSM (Device Specific

 * Method), then the SMBIOS type 41 instance number and string is exported to

 * sysfs.

 *

 * SMBIOS defines type 41 for onboard pci devices. This code retrieves

 * the instance number and string from the type 41 record and exports

 * it to sysfs.

 *

 * Please see http://linux.dell.com/files/biosdevname/ for more

 * information.

 */

​

#include <linux/dmi.h>

#include <linux/sysfs.h>

#include <linux/pci.h>

#include <linux/pci_ids.h>

#include <linux/module.h>

#include <linux/device.h>

#include <linux/nls.h>

#include <linux/acpi.h>

#include <linux/pci-acpi.h>

#include "pci.h"

​

#ifdef CONFIG_DMI

enum smbios_attr_enum {

    SMBIOS_ATTR_NONE = 0,

    SMBIOS_ATTR_LABEL_SHOW,

    SMBIOS_ATTR_INSTANCE_SHOW,

};

​

static size_t find_smbios_instance_string(struct pci_dev *pdev, char *buf,

                      enum smbios_attr_enum attribute)

{

    const struct dmi_device *dmi;

    struct dmi_dev_onboard *donboard;

    int domain_nr;

    int bus;

    int devfn;

​

    domain_nr = pci_domain_nr(pdev->bus);

    bus = pdev->bus->number;

    devfn = pdev->devfn;

​

    dmi = NULL;

    while ((dmi = dmi_find_device(DMI_DEV_TYPE_DEV_ONBOARD,

                      NULL, dmi)) != NULL) {

        donboard = dmi->device_data;

        if (donboard && donboard->segment == domain_nr &&

                donboard->bus == bus &&

                donboard->devfn == devfn) {

            if (buf) {

                if (attribute == SMBIOS_ATTR_INSTANCE_SHOW)

                    return scnprintf(buf, PAGE_SIZE,

                             "%d\n",

                             donboard->instance);

                else if (attribute == SMBIOS_ATTR_LABEL_SHOW)

                    return scnprintf(buf, PAGE_SIZE,

                             "%s\n",

                             dmi->name);

            }

            return strlen(dmi->name);

        }

    }

    return 0;

}

​

static umode_t smbios_instance_string_exist(struct kobject *kobj,

                        struct attribute *attr, int n)

{

    struct device *dev;

    struct pci_dev *pdev;

​

    dev = kobj_to_dev(kobj);

    pdev = to_pci_dev(dev);

​

    return find_smbios_instance_string(pdev, NULL, SMBIOS_ATTR_NONE) ?

                       S_IRUGO : 0;

}

​

static ssize_t smbioslabel_show(struct device *dev,