1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Lenovo Legion WMI helpers driver.
4 *
5 * The Lenovo Legion WMI interface is broken up into multiple GUID interfaces
6 * that require cross-references between GUID's for some functionality. The
7 * "Custom Mode" interface is a legacy interface for managing and displaying
8 * CPU & GPU power and hwmon settings and readings. The "Other Mode" interface
9 * is a modern interface that replaces or extends the "Custom Mode" interface
10 * methods. The "Gamezone" interface adds advanced features such as fan
11 * profiles and overclocking. The "Lighting" interface adds control of various
12 * status lights related to different hardware components. Each of these
13 * drivers uses a common procedure to get data from the WMI interface,
14 * enumerated here.
15 *
16 * Copyright (C) 2025 Derek J. Clark <derekjohn.clark@gmail.com>
17 */
18
19 #include <linux/acpi.h>
20 #include <linux/cleanup.h>
21 #include <linux/errno.h>
22 #include <linux/export.h>
23 #include <linux/module.h>
24 #include <linux/unaligned.h>
25 #include <linux/wmi.h>
26
27 #include "wmi-helpers.h"
28
29 /**
30 * lwmi_dev_evaluate_int() - Helper function for calling WMI methods that
31 * return an integer.
32 * @wdev: Pointer to the WMI device to be called.
33 * @instance: Instance of the called method.
34 * @method_id: WMI Method ID for the method to be called.
35 * @buf: Buffer of all arguments for the given method_id.
36 * @size: Length of the buffer.
37 * @retval: Pointer for the return value to be assigned.
38 *
39 * Calls wmidev_evaluate_method for Lenovo WMI devices that return an ACPI
40 * integer. Validates the return value type and assigns the value to the
41 * retval pointer.
42 *
43 * Return: 0 on success, or an error code.
44 */
lwmi_dev_evaluate_int(struct wmi_device * wdev,u8 instance,u32 method_id,unsigned char * buf,size_t size,u32 * retval)45 int lwmi_dev_evaluate_int(struct wmi_device *wdev, u8 instance, u32 method_id,
46 unsigned char *buf, size_t size, u32 *retval)
47 {
48 struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
49 union acpi_object *ret_obj __free(kfree) = NULL;
50 struct acpi_buffer input = { size, buf };
51 acpi_status status;
52
53 status = wmidev_evaluate_method(wdev, instance, method_id, &input,
54 &output);
55 if (ACPI_FAILURE(status))
56 return -EIO;
57
58 if (retval) {
59 ret_obj = output.pointer;
60 if (!ret_obj)
61 return -ENODATA;
62
63 switch (ret_obj->type) {
64 /*
65 * The ACPI method may simply return a buffer when a u32
66 * is expected. This is valid on Windows as its WMI-ACPI
67 * driver converts everything to a common buffer.
68 */
69 case ACPI_TYPE_BUFFER:
70 if (ret_obj->buffer.length < sizeof(u32))
71 return -ENXIO;
72
73 *retval = get_unaligned_le32(ret_obj->buffer.pointer);
74 return 0;
75 case ACPI_TYPE_INTEGER:
76 *retval = (u32)ret_obj->integer.value;
77 return 0;
78 default:
79 return -ENXIO;
80 }
81 }
82
83 return 0;
84 };
85 EXPORT_SYMBOL_NS_GPL(lwmi_dev_evaluate_int, "LENOVO_WMI_HELPERS");
86
87 MODULE_AUTHOR("Derek J. Clark <derekjohn.clark@gmail.com>");
88 MODULE_DESCRIPTION("Lenovo WMI Helpers Driver");
89 MODULE_LICENSE("GPL");
90