LXR linux/drivers/platform/x86/wmi-bmof.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * WMI embedded Binary MOF driver
   4 *
   5 * Copyright (c) 2015 Andrew Lutomirski
   6 * Copyright (C) 2017 VMware, Inc. All Rights Reserved.
   7 */
   8
   9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11#include <linux/acpi.h>
  12#include <linux/device.h>
  13#include <linux/fs.h>
  14#include <linux/kernel.h>
  15#include <linux/module.h>
  16#include <linux/string.h>
  17#include <linux/sysfs.h>
  18#include <linux/types.h>
  19#include <linux/wmi.h>
  20
  21#define WMI_BMOF_GUID "05901221-D566-11D1-B2F0-00A0C9062910"
  22
  23struct bmof_priv {
  24        union acpi_object *bmofdata;
  25        struct bin_attribute bmof_bin_attr;
  26};
  27
  28static ssize_t
  29read_bmof(struct file *filp, struct kobject *kobj,
  30         struct bin_attribute *attr,
  31         char *buf, loff_t off, size_t count)
  32{
  33        struct bmof_priv *priv =
  34                container_of(attr, struct bmof_priv, bmof_bin_attr);
  35
  36        if (off < 0)
  37                return -EINVAL;
  38
  39        if (off >= priv->bmofdata->buffer.length)
  40                return 0;
  41
  42        if (count > priv->bmofdata->buffer.length - off)
  43                count = priv->bmofdata->buffer.length - off;
  44
  45        memcpy(buf, priv->bmofdata->buffer.pointer + off, count);
  46        return count;
  47}
  48
  49static int wmi_bmof_probe(struct wmi_device *wdev, const void *context)
  50{
  51        struct bmof_priv *priv;
  52        int ret;
  53
  54        priv = devm_kzalloc(&wdev->dev, sizeof(struct bmof_priv), GFP_KERNEL);
  55        if (!priv)
  56                return -ENOMEM;
  57
  58        dev_set_drvdata(&wdev->dev, priv);
  59
  60        priv->bmofdata = wmidev_block_query(wdev, 0);
  61        if (!priv->bmofdata) {
  62                dev_err(&wdev->dev, "failed to read Binary MOF\n");
  63                return -EIO;
  64        }
  65
  66        if (priv->bmofdata->type != ACPI_TYPE_BUFFER) {
  67                dev_err(&wdev->dev, "Binary MOF is not a buffer\n");
  68                ret = -EIO;
  69                goto err_free;
  70        }
  71
  72        sysfs_bin_attr_init(&priv->bmof_bin_attr);
  73        priv->bmof_bin_attr.attr.name = "bmof";
  74        priv->bmof_bin_attr.attr.mode = 0400;
  75        priv->bmof_bin_attr.read = read_bmof;
  76        priv->bmof_bin_attr.size = priv->bmofdata->buffer.length;
  77
  78        ret = sysfs_create_bin_file(&wdev->dev.kobj, &priv->bmof_bin_attr);
  79        if (ret)
  80                goto err_free;
  81
  82        return 0;
  83
  84 err_free:
  85        kfree(priv->bmofdata);
  86        return ret;
  87}
  88
  89static int wmi_bmof_remove(struct wmi_device *wdev)
  90{
  91        struct bmof_priv *priv = dev_get_drvdata(&wdev->dev);
  92
  93        sysfs_remove_bin_file(&wdev->dev.kobj, &priv->bmof_bin_attr);
  94        kfree(priv->bmofdata);
  95        return 0;
  96}
  97
  98static const struct wmi_device_id wmi_bmof_id_table[] = {
  99        { .guid_string = WMI_BMOF_GUID },
 100        { },
 101};
 102
 103static struct wmi_driver wmi_bmof_driver = {
 104        .driver = {
 105                .name = "wmi-bmof",
 106        },
 107        .probe = wmi_bmof_probe,
 108        .remove = wmi_bmof_remove,
 109        .id_table = wmi_bmof_id_table,
 110};
 111
 112module_wmi_driver(wmi_bmof_driver);
 113
 114MODULE_DEVICE_TABLE(wmi, wmi_bmof_id_table);
 115MODULE_AUTHOR("Andrew Lutomirski <luto@kernel.org>");
 116MODULE_DESCRIPTION("WMI embedded Binary MOF driver");
 117MODULE_LICENSE("GPL");
 118