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
  23 struct bmof_priv {
  24         union acpi_object *bmofdata;
  25         struct bin_attribute bmof_bin_attr;
  26 };
  27
  28 static ssize_t read_bmof(struct file *filp, struct kobject *kobj, struct bin_attribute *attr,
  29                          char *buf, loff_t off, size_t count)
  30 {
  31         struct bmof_priv *priv = container_of(attr, struct bmof_priv, bmof_bin_attr);
  32
  33         return memory_read_from_buffer(buf, count, &off, priv->bmofdata->buffer.pointer,
  34                                        priv->bmofdata->buffer.length);
  35 }
  36
  37 static int wmi_bmof_probe(struct wmi_device *wdev, const void *context)
  38 {
  39         struct bmof_priv *priv;
  40         int ret;
  41
  42         priv = devm_kzalloc(&wdev->dev, sizeof(struct bmof_priv), GFP_KERNEL);
  43         if (!priv)
  44                 return -ENOMEM;
  45
  46         dev_set_drvdata(&wdev->dev, priv);
  47
  48         priv->bmofdata = wmidev_block_query(wdev, 0);
  49         if (!priv->bmofdata) {
  50                 dev_err(&wdev->dev, "failed to read Binary MOF\n");
  51                 return -EIO;
  52         }
  53
  54         if (priv->bmofdata->type != ACPI_TYPE_BUFFER) {
  55                 dev_err(&wdev->dev, "Binary MOF is not a buffer\n");
  56                 ret = -EIO;
  57                 goto err_free;
  58         }
  59
  60         sysfs_bin_attr_init(&priv->bmof_bin_attr);
  61         priv->bmof_bin_attr.attr.name = "bmof";
  62         priv->bmof_bin_attr.attr.mode = 0400;
  63         priv->bmof_bin_attr.read = read_bmof;
  64         priv->bmof_bin_attr.size = priv->bmofdata->buffer.length;
  65
  66         ret = device_create_bin_file(&wdev->dev, &priv->bmof_bin_attr);
  67         if (ret)
  68                 goto err_free;
  69
  70         return 0;
  71
  72  err_free:
  73         kfree(priv->bmofdata);
  74         return ret;
  75 }
  76
  77 static void wmi_bmof_remove(struct wmi_device *wdev)
  78 {
  79         struct bmof_priv *priv = dev_get_drvdata(&wdev->dev);
  80
  81         device_remove_bin_file(&wdev->dev, &priv->bmof_bin_attr);
  82         kfree(priv->bmofdata);
  83 }
  84
  85 static const struct wmi_device_id wmi_bmof_id_table[] = {
  86         { .guid_string = WMI_BMOF_GUID },
  87         { },
  88 };
  89
  90 static struct wmi_driver wmi_bmof_driver = {
  91         .driver = {
  92                 .name = "wmi-bmof",
  93         },
  94         .probe = wmi_bmof_probe,
  95         .remove = wmi_bmof_remove,
  96         .id_table = wmi_bmof_id_table,
  97         .no_singleton = true,
  98 };
  99
 100 module_wmi_driver(wmi_bmof_driver);
 101
 102 MODULE_DEVICE_TABLE(wmi, wmi_bmof_id_table);
 103 MODULE_AUTHOR("Andrew Lutomirski <luto@kernel.org>");
 104 MODULE_DESCRIPTION("WMI embedded Binary MOF driver");
 105 MODULE_LICENSE("GPL");