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 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
 37static 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
 77static 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
 85static const struct wmi_device_id wmi_bmof_id_table[] = {
 86	{ .guid_string = WMI_BMOF_GUID },
 87	{ },
 88};
 89
 90static 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
100module_wmi_driver(wmi_bmof_driver);
101
102MODULE_DEVICE_TABLE(wmi, wmi_bmof_id_table);
103MODULE_AUTHOR("Andrew Lutomirski <luto@kernel.org>");
104MODULE_DESCRIPTION("WMI embedded Binary MOF driver");
105MODULE_LICENSE("GPL");