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1// SPDX-License-Identifier: GPL-2.02/*3 * Functions corresponding to methods under BIOS interface GUID4 * for use with hp-bioscfg driver.5 *6 * Copyright (c) 2022 Hewlett-Packard Inc.7 */8 9#include <linux/wmi.h>10#include "bioscfg.h"11 12/*13 * struct bios_args buffer is dynamically allocated. New WMI command types14 * were introduced that exceeds 128-byte data size. Changes to handle15 * the data size allocation scheme were kept in hp_wmi_perform_query function.16 */17struct bios_args {18 u32 signature;19 u32 command;20 u32 commandtype;21 u32 datasize;22 u8 data[] __counted_by(datasize);23};24 25/**26 * hp_set_attribute27 *28 * @a_name: The attribute name29 * @a_value: The attribute value30 *31 * Sets an attribute to new value32 *33 * Returns zero on success34 * -ENODEV if device is not found35 * -EINVAL if the instance of 'Setup Admin' password is not found.36 * -ENOMEM unable to allocate memory37 */38int hp_set_attribute(const char *a_name, const char *a_value)39{40 int security_area_size;41 int a_name_size, a_value_size;42 u16 *buffer = NULL;43 u16 *start;44 int buffer_size, instance, ret;45 char *auth_token_choice;46 47 mutex_lock(&bioscfg_drv.mutex);48 49 instance = hp_get_password_instance_for_type(SETUP_PASSWD);50 if (instance < 0) {51 ret = -EINVAL;52 goto out_set_attribute;53 }54 55 /* Select which auth token to use; password or [auth token] */56 if (bioscfg_drv.spm_data.auth_token)57 auth_token_choice = bioscfg_drv.spm_data.auth_token;58 else59 auth_token_choice = bioscfg_drv.password_data[instance].current_password;60 61 a_name_size = hp_calculate_string_buffer(a_name);62 a_value_size = hp_calculate_string_buffer(a_value);63 security_area_size = hp_calculate_security_buffer(auth_token_choice);64 buffer_size = a_name_size + a_value_size + security_area_size;65 66 buffer = kmalloc(buffer_size + 1, GFP_KERNEL);67 if (!buffer) {68 ret = -ENOMEM;69 goto out_set_attribute;70 }71 72 /* build variables to set */73 start = buffer;74 start = hp_ascii_to_utf16_unicode(start, a_name);75 if (!start) {76 ret = -EINVAL;77 goto out_set_attribute;78 }79 80 start = hp_ascii_to_utf16_unicode(start, a_value);81 if (!start) {82 ret = -EINVAL;83 goto out_set_attribute;84 }85 86 ret = hp_populate_security_buffer(start, auth_token_choice);87 if (ret < 0)88 goto out_set_attribute;89 90 ret = hp_wmi_set_bios_setting(buffer, buffer_size);91 92out_set_attribute:93 kfree(buffer);94 mutex_unlock(&bioscfg_drv.mutex);95 return ret;96}97 98/**99 * hp_wmi_perform_query100 *101 * @query: The commandtype (enum hp_wmi_commandtype)102 * @command: The command (enum hp_wmi_command)103 * @buffer: Buffer used as input and/or output104 * @insize: Size of input buffer105 * @outsize: Size of output buffer106 *107 * returns zero on success108 * an HP WMI query specific error code (which is positive)109 * -EINVAL if the query was not successful at all110 * -EINVAL if the output buffer size exceeds buffersize111 *112 * Note: The buffersize must at least be the maximum of the input and output113 * size. E.g. Battery info query is defined to have 1 byte input114 * and 128 byte output. The caller would do:115 * buffer = kzalloc(128, GFP_KERNEL);116 * ret = hp_wmi_perform_query(HPWMI_BATTERY_QUERY, HPWMI_READ,117 * buffer, 1, 128)118 */119int hp_wmi_perform_query(int query, enum hp_wmi_command command, void *buffer,120 u32 insize, u32 outsize)121{122 struct acpi_buffer input, output = { ACPI_ALLOCATE_BUFFER, NULL };123 struct bios_return *bios_return;124 union acpi_object *obj = NULL;125 struct bios_args *args = NULL;126 int mid, actual_outsize, ret;127 size_t bios_args_size;128 129 mid = hp_encode_outsize_for_pvsz(outsize);130 if (WARN_ON(mid < 0))131 return mid;132 133 bios_args_size = struct_size(args, data, insize);134 args = kmalloc(bios_args_size, GFP_KERNEL);135 if (!args)136 return -ENOMEM;137 138 input.length = bios_args_size;139 input.pointer = args;140 141 /* BIOS expects 'SECU' in hex as the signature value*/142 args->signature = 0x55434553;143 args->command = command;144 args->commandtype = query;145 args->datasize = insize;146 memcpy(args->data, buffer, flex_array_size(args, data, insize));147 148 ret = wmi_evaluate_method(HP_WMI_BIOS_GUID, 0, mid, &input, &output);149 if (ret)150 goto out_free;151 152 obj = output.pointer;153 if (!obj) {154 ret = -EINVAL;155 goto out_free;156 }157 158 if (obj->type != ACPI_TYPE_BUFFER ||159 obj->buffer.length < sizeof(*bios_return)) {160 pr_warn("query 0x%x returned wrong type or too small buffer\n", query);161 ret = -EINVAL;162 goto out_free;163 }164 165 bios_return = (struct bios_return *)obj->buffer.pointer;166 ret = bios_return->return_code;167 if (ret) {168 if (ret != INVALID_CMD_VALUE && ret != INVALID_CMD_TYPE)169 pr_warn("query 0x%x returned error 0x%x\n", query, ret);170 goto out_free;171 }172 173 /* Ignore output data of zero size */174 if (!outsize)175 goto out_free;176 177 actual_outsize = min_t(u32, outsize, obj->buffer.length - sizeof(*bios_return));178 memcpy_and_pad(buffer, outsize, obj->buffer.pointer + sizeof(*bios_return),179 actual_outsize, 0);180 181out_free:182 ret = hp_wmi_error_and_message(ret);183 184 kfree(obj);185 kfree(args);186 return ret;187}188 189static void *utf16_empty_string(u16 *p)190{191 *p++ = 2;192 *p++ = 0x00;193 return p;194}195 196/**197 * hp_ascii_to_utf16_unicode - Convert ascii string to UTF-16 unicode198 *199 * BIOS supports UTF-16 characters that are 2 bytes long. No variable200 * multi-byte language supported.201 *202 * @p: Unicode buffer address203 * @str: string to convert to unicode204 *205 * Returns a void pointer to the buffer string206 */207void *hp_ascii_to_utf16_unicode(u16 *p, const u8 *str)208{209 int len = strlen(str);210 int ret;211 212 /*213 * Add null character when reading an empty string214 * "02 00 00 00"215 */216 if (len == 0)217 return utf16_empty_string(p);218 219 /* Move pointer len * 2 number of bytes */220 *p++ = len * 2;221 ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN, p, len);222 if (ret < 0) {223 dev_err(bioscfg_drv.class_dev, "UTF16 conversion failed\n");224 return NULL;225 }226 227 if (ret * sizeof(u16) > U16_MAX) {228 dev_err(bioscfg_drv.class_dev, "Error string too long\n");229 return NULL;230 }231 232 p += len;233 return p;234}235 236/**237 * hp_wmi_set_bios_setting - Set setting's value in BIOS238 *239 * @input_buffer: Input buffer address240 * @input_size: Input buffer size241 *242 * Returns: Count of unicode characters written to BIOS if successful, otherwise243 * -ENOMEM unable to allocate memory244 * -EINVAL buffer not allocated or too small245 */246int hp_wmi_set_bios_setting(u16 *input_buffer, u32 input_size)247{248 union acpi_object *obj;249 struct acpi_buffer input = {input_size, input_buffer};250 struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};251 int ret;252 253 ret = wmi_evaluate_method(HP_WMI_SET_BIOS_SETTING_GUID, 0, 1, &input, &output);254 255 obj = output.pointer;256 if (!obj)257 return -EINVAL;258 259 if (obj->type != ACPI_TYPE_INTEGER) {260 ret = -EINVAL;261 goto out_free;262 }263 264 ret = obj->integer.value;265 if (ret) {266 ret = hp_wmi_error_and_message(ret);267 goto out_free;268 }269 270out_free:271 kfree(obj);272 return ret;273}274 275static int hp_attr_set_interface_probe(struct wmi_device *wdev, const void *context)276{277 mutex_lock(&bioscfg_drv.mutex);278 mutex_unlock(&bioscfg_drv.mutex);279 return 0;280}281 282static void hp_attr_set_interface_remove(struct wmi_device *wdev)283{284 mutex_lock(&bioscfg_drv.mutex);285 mutex_unlock(&bioscfg_drv.mutex);286}287 288static const struct wmi_device_id hp_attr_set_interface_id_table[] = {289 { .guid_string = HP_WMI_BIOS_GUID},290 { }291};292 293static struct wmi_driver hp_attr_set_interface_driver = {294 .driver = {295 .name = DRIVER_NAME,296 },297 .probe = hp_attr_set_interface_probe,298 .remove = hp_attr_set_interface_remove,299 .id_table = hp_attr_set_interface_id_table,300};301 302int hp_init_attr_set_interface(void)303{304 return wmi_driver_register(&hp_attr_set_interface_driver);305}306 307void hp_exit_attr_set_interface(void)308{309 wmi_driver_unregister(&hp_attr_set_interface_driver);310}311 312MODULE_DEVICE_TABLE(wmi, hp_attr_set_interface_id_table);313