diff options
Diffstat (limited to 'drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c')
-rw-r--r-- | drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c | 312 |
1 files changed, 312 insertions, 0 deletions
diff --git a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c new file mode 100644 index 0000000000..dea54f35b8 --- /dev/null +++ b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c @@ -0,0 +1,312 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Functions corresponding to methods under BIOS interface GUID + * for use with hp-bioscfg driver. + * + * Copyright (c) 2022 Hewlett-Packard Inc. + */ + +#include <linux/wmi.h> +#include "bioscfg.h" + +/* + * struct bios_args buffer is dynamically allocated. New WMI command types + * were introduced that exceeds 128-byte data size. Changes to handle + * the data size allocation scheme were kept in hp_wmi_perform_query function. + */ +struct bios_args { + u32 signature; + u32 command; + u32 commandtype; + u32 datasize; + u8 data[]; +}; + +/** + * hp_set_attribute + * + * @a_name: The attribute name + * @a_value: The attribute value + * + * Sets an attribute to new value + * + * Returns zero on success + * -ENODEV if device is not found + * -EINVAL if the instance of 'Setup Admin' password is not found. + * -ENOMEM unable to allocate memory + */ +int hp_set_attribute(const char *a_name, const char *a_value) +{ + int security_area_size; + int a_name_size, a_value_size; + u16 *buffer = NULL; + u16 *start; + int buffer_size, instance, ret; + char *auth_token_choice; + + mutex_lock(&bioscfg_drv.mutex); + + instance = hp_get_password_instance_for_type(SETUP_PASSWD); + if (instance < 0) { + ret = -EINVAL; + goto out_set_attribute; + } + + /* Select which auth token to use; password or [auth token] */ + if (bioscfg_drv.spm_data.auth_token) + auth_token_choice = bioscfg_drv.spm_data.auth_token; + else + auth_token_choice = bioscfg_drv.password_data[instance].current_password; + + a_name_size = hp_calculate_string_buffer(a_name); + a_value_size = hp_calculate_string_buffer(a_value); + security_area_size = hp_calculate_security_buffer(auth_token_choice); + buffer_size = a_name_size + a_value_size + security_area_size; + + buffer = kmalloc(buffer_size + 1, GFP_KERNEL); + if (!buffer) { + ret = -ENOMEM; + goto out_set_attribute; + } + + /* build variables to set */ + start = buffer; + start = hp_ascii_to_utf16_unicode(start, a_name); + if (!start) { + ret = -EINVAL; + goto out_set_attribute; + } + + start = hp_ascii_to_utf16_unicode(start, a_value); + if (!start) { + ret = -EINVAL; + goto out_set_attribute; + } + + ret = hp_populate_security_buffer(start, auth_token_choice); + if (ret < 0) + goto out_set_attribute; + + ret = hp_wmi_set_bios_setting(buffer, buffer_size); + +out_set_attribute: + kfree(buffer); + mutex_unlock(&bioscfg_drv.mutex); + return ret; +} + +/** + * hp_wmi_perform_query + * + * @query: The commandtype (enum hp_wmi_commandtype) + * @command: The command (enum hp_wmi_command) + * @buffer: Buffer used as input and/or output + * @insize: Size of input buffer + * @outsize: Size of output buffer + * + * returns zero on success + * an HP WMI query specific error code (which is positive) + * -EINVAL if the query was not successful at all + * -EINVAL if the output buffer size exceeds buffersize + * + * Note: The buffersize must at least be the maximum of the input and output + * size. E.g. Battery info query is defined to have 1 byte input + * and 128 byte output. The caller would do: + * buffer = kzalloc(128, GFP_KERNEL); + * ret = hp_wmi_perform_query(HPWMI_BATTERY_QUERY, HPWMI_READ, + * buffer, 1, 128) + */ +int hp_wmi_perform_query(int query, enum hp_wmi_command command, void *buffer, + u32 insize, u32 outsize) +{ + struct acpi_buffer input, output = { ACPI_ALLOCATE_BUFFER, NULL }; + struct bios_return *bios_return; + union acpi_object *obj = NULL; + struct bios_args *args = NULL; + int mid, actual_outsize, ret; + size_t bios_args_size; + + mid = hp_encode_outsize_for_pvsz(outsize); + if (WARN_ON(mid < 0)) + return mid; + + bios_args_size = struct_size(args, data, insize); + args = kmalloc(bios_args_size, GFP_KERNEL); + if (!args) + return -ENOMEM; + + input.length = bios_args_size; + input.pointer = args; + + /* BIOS expects 'SECU' in hex as the signature value*/ + args->signature = 0x55434553; + args->command = command; + args->commandtype = query; + args->datasize = insize; + memcpy(args->data, buffer, flex_array_size(args, data, insize)); + + ret = wmi_evaluate_method(HP_WMI_BIOS_GUID, 0, mid, &input, &output); + if (ret) + goto out_free; + + obj = output.pointer; + if (!obj) { + ret = -EINVAL; + goto out_free; + } + + if (obj->type != ACPI_TYPE_BUFFER || + obj->buffer.length < sizeof(*bios_return)) { + pr_warn("query 0x%x returned wrong type or too small buffer\n", query); + ret = -EINVAL; + goto out_free; + } + + bios_return = (struct bios_return *)obj->buffer.pointer; + ret = bios_return->return_code; + if (ret) { + if (ret != INVALID_CMD_VALUE && ret != INVALID_CMD_TYPE) + pr_warn("query 0x%x returned error 0x%x\n", query, ret); + goto out_free; + } + + /* Ignore output data of zero size */ + if (!outsize) + goto out_free; + + actual_outsize = min_t(u32, outsize, obj->buffer.length - sizeof(*bios_return)); + memcpy_and_pad(buffer, outsize, obj->buffer.pointer + sizeof(*bios_return), + actual_outsize, 0); + +out_free: + ret = hp_wmi_error_and_message(ret); + + kfree(obj); + kfree(args); + return ret; +} + +static void *utf16_empty_string(u16 *p) +{ + *p++ = 2; + *p++ = 0x00; + return p; +} + +/** + * hp_ascii_to_utf16_unicode - Convert ascii string to UTF-16 unicode + * + * BIOS supports UTF-16 characters that are 2 bytes long. No variable + * multi-byte language supported. + * + * @p: Unicode buffer address + * @str: string to convert to unicode + * + * Returns a void pointer to the buffer string + */ +void *hp_ascii_to_utf16_unicode(u16 *p, const u8 *str) +{ + int len = strlen(str); + int ret; + + /* + * Add null character when reading an empty string + * "02 00 00 00" + */ + if (len == 0) + return utf16_empty_string(p); + + /* Move pointer len * 2 number of bytes */ + *p++ = len * 2; + ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN, p, len); + if (ret < 0) { + dev_err(bioscfg_drv.class_dev, "UTF16 conversion failed\n"); + return NULL; + } + + if (ret * sizeof(u16) > U16_MAX) { + dev_err(bioscfg_drv.class_dev, "Error string too long\n"); + return NULL; + } + + p += len; + return p; +} + +/** + * hp_wmi_set_bios_setting - Set setting's value in BIOS + * + * @input_buffer: Input buffer address + * @input_size: Input buffer size + * + * Returns: Count of unicode characters written to BIOS if successful, otherwise + * -ENOMEM unable to allocate memory + * -EINVAL buffer not allocated or too small + */ +int hp_wmi_set_bios_setting(u16 *input_buffer, u32 input_size) +{ + union acpi_object *obj; + struct acpi_buffer input = {input_size, input_buffer}; + struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL}; + int ret; + + ret = wmi_evaluate_method(HP_WMI_SET_BIOS_SETTING_GUID, 0, 1, &input, &output); + + obj = output.pointer; + if (!obj) + return -EINVAL; + + if (obj->type != ACPI_TYPE_INTEGER) { + ret = -EINVAL; + goto out_free; + } + + ret = obj->integer.value; + if (ret) { + ret = hp_wmi_error_and_message(ret); + goto out_free; + } + +out_free: + kfree(obj); + return ret; +} + +static int hp_attr_set_interface_probe(struct wmi_device *wdev, const void *context) +{ + mutex_lock(&bioscfg_drv.mutex); + mutex_unlock(&bioscfg_drv.mutex); + return 0; +} + +static void hp_attr_set_interface_remove(struct wmi_device *wdev) +{ + mutex_lock(&bioscfg_drv.mutex); + mutex_unlock(&bioscfg_drv.mutex); +} + +static const struct wmi_device_id hp_attr_set_interface_id_table[] = { + { .guid_string = HP_WMI_BIOS_GUID}, + { } +}; + +static struct wmi_driver hp_attr_set_interface_driver = { + .driver = { + .name = DRIVER_NAME, + }, + .probe = hp_attr_set_interface_probe, + .remove = hp_attr_set_interface_remove, + .id_table = hp_attr_set_interface_id_table, +}; + +int hp_init_attr_set_interface(void) +{ + return wmi_driver_register(&hp_attr_set_interface_driver); +} + +void hp_exit_attr_set_interface(void) +{ + wmi_driver_unregister(&hp_attr_set_interface_driver); +} + +MODULE_DEVICE_TABLE(wmi, hp_attr_set_interface_id_table); |