drivers/platform/x86/dell-wmi-sysman/biosattr-interface.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Functions corresponding to SET methods under BIOS attributes interface GUID for use
   4  * with dell-wmi-sysman
   5  *
   6  *  Copyright (c) 2020 Dell Inc.
   7  */
   8
   9 #include <linux/wmi.h>
  10 #include "dell-wmi-sysman.h"
  11
  12 #define SETDEFAULTVALUES_METHOD_ID                                      0x02
  13 #define SETBIOSDEFAULTS_METHOD_ID                                       0x03
  14 #define SETATTRIBUTE_METHOD_ID                                          0x04
  15
  16 static int call_biosattributes_interface(struct wmi_device *wdev, char *in_args, size_t size,
  17                                         int method_id)
  18 {
  19         struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
  20         struct acpi_buffer input;
  21         union acpi_object *obj;
  22         acpi_status status;
  23         int ret = -EIO;
  24
  25         input.length =  (acpi_size) size;
  26         input.pointer = in_args;
  27         status = wmidev_evaluate_method(wdev, 0, method_id, &input, &output);
  28         if (ACPI_FAILURE(status))
  29                 return -EIO;
  30         obj = (union acpi_object *)output.pointer;
  31         if (obj->type == ACPI_TYPE_INTEGER)
  32                 ret = obj->integer.value;
  33
  34         if (wmi_priv.pending_changes == 0) {
  35                 wmi_priv.pending_changes = 1;
  36                 /* let userland know it may need to check reboot pending again */
  37                 kobject_uevent(&wmi_priv.class_dev->kobj, KOBJ_CHANGE);
  38         }
  39         kfree(output.pointer);
  40         return map_wmi_error(ret);
  41 }
  42
  43 /**
  44  * set_attribute() - Update an attribute value
  45  * @a_name: The attribute name
  46  * @a_value: The attribute value
  47  *
  48  * Sets an attribute to new value
  49  */
  50 int set_attribute(const char *a_name, const char *a_value)
  51 {
  52         size_t security_area_size, buffer_size;
  53         size_t a_name_size, a_value_size;
  54         char *buffer = NULL, *start;
  55         int ret;
  56
  57         mutex_lock(&wmi_priv.mutex);
  58         if (!wmi_priv.bios_attr_wdev) {
  59                 ret = -ENODEV;
  60                 goto out;
  61         }
  62
  63         /* build/calculate buffer */
  64         security_area_size = calculate_security_buffer(wmi_priv.current_admin_password);
  65         a_name_size = calculate_string_buffer(a_name);
  66         a_value_size = calculate_string_buffer(a_value);
  67         buffer_size = security_area_size + a_name_size + a_value_size;
  68         buffer = kzalloc(buffer_size, GFP_KERNEL);
  69         if (!buffer) {
  70                 ret = -ENOMEM;
  71                 goto out;
  72         }
  73
  74         /* build security area */
  75         populate_security_buffer(buffer, wmi_priv.current_admin_password);
  76
  77         /* build variables to set */
  78         start = buffer + security_area_size;
  79         ret = populate_string_buffer(start, a_name_size, a_name);
  80         if (ret < 0)
  81                 goto out;
  82         start += ret;
  83         ret = populate_string_buffer(start, a_value_size, a_value);
  84         if (ret < 0)
  85                 goto out;
  86
  87         print_hex_dump_bytes("set attribute data: ", DUMP_PREFIX_NONE, buffer, buffer_size);
  88         ret = call_biosattributes_interface(wmi_priv.bios_attr_wdev,
  89                                             buffer, buffer_size,
  90                                             SETATTRIBUTE_METHOD_ID);
  91         if (ret == -EOPNOTSUPP)
  92                 dev_err(&wmi_priv.bios_attr_wdev->dev, "admin password must be configured\n");
  93         else if (ret == -EACCES)
  94                 dev_err(&wmi_priv.bios_attr_wdev->dev, "invalid password\n");
  95
  96 out:
  97         kfree(buffer);
  98         mutex_unlock(&wmi_priv.mutex);
  99         return ret;
 100 }
 101
 102 /**
 103  * set_bios_defaults() - Resets BIOS defaults
 104  * @deftype: the type of BIOS value reset to issue.
 105  *
 106  * Resets BIOS defaults
 107  */
 108 int set_bios_defaults(u8 deftype)
 109 {
 110         size_t security_area_size, buffer_size;
 111         size_t integer_area_size = sizeof(u8);
 112         char *buffer = NULL;
 113         u8 *defaultType;
 114         int ret;
 115
 116         mutex_lock(&wmi_priv.mutex);
 117         if (!wmi_priv.bios_attr_wdev) {
 118                 ret = -ENODEV;
 119                 goto out;
 120         }
 121
 122         security_area_size = calculate_security_buffer(wmi_priv.current_admin_password);
 123         buffer_size = security_area_size + integer_area_size;
 124         buffer = kzalloc(buffer_size, GFP_KERNEL);
 125         if (!buffer) {
 126                 ret = -ENOMEM;
 127                 goto out;
 128         }
 129
 130         /* build security area */
 131         populate_security_buffer(buffer, wmi_priv.current_admin_password);
 132
 133         defaultType = buffer + security_area_size;
 134         *defaultType = deftype;
 135
 136         ret = call_biosattributes_interface(wmi_priv.bios_attr_wdev, buffer, buffer_size,
 137                                             SETBIOSDEFAULTS_METHOD_ID);
 138         if (ret)
 139                 dev_err(&wmi_priv.bios_attr_wdev->dev, "reset BIOS defaults failed: %d\n", ret);
 140
 141         kfree(buffer);
 142 out:
 143         mutex_unlock(&wmi_priv.mutex);
 144         return ret;
 145 }
 146
 147 static int bios_attr_set_interface_probe(struct wmi_device *wdev, const void *context)
 148 {
 149         mutex_lock(&wmi_priv.mutex);
 150         wmi_priv.bios_attr_wdev = wdev;
 151         mutex_unlock(&wmi_priv.mutex);
 152         return 0;
 153 }
 154
 155 static int bios_attr_set_interface_remove(struct wmi_device *wdev)
 156 {
 157         mutex_lock(&wmi_priv.mutex);
 158         wmi_priv.bios_attr_wdev = NULL;
 159         mutex_unlock(&wmi_priv.mutex);
 160         return 0;
 161 }
 162
 163 static const struct wmi_device_id bios_attr_set_interface_id_table[] = {
 164         { .guid_string = DELL_WMI_BIOS_ATTRIBUTES_INTERFACE_GUID },
 165         { },
 166 };
 167 static struct wmi_driver bios_attr_set_interface_driver = {
 168         .driver = {
 169                 .name = DRIVER_NAME
 170         },
 171         .probe = bios_attr_set_interface_probe,
 172         .remove = bios_attr_set_interface_remove,
 173         .id_table = bios_attr_set_interface_id_table,
 174 };
 175
 176 int init_bios_attr_set_interface(void)
 177 {
 178         return wmi_driver_register(&bios_attr_set_interface_driver);
 179 }
 180
 181 void exit_bios_attr_set_interface(void)
 182 {
 183         wmi_driver_unregister(&bios_attr_set_interface_driver);
 184 }
 185
 186 MODULE_DEVICE_TABLE(wmi, bios_attr_set_interface_id_table);