// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Think LMI BIOS configuration driver
 *
 * Copyright(C) 2019-2021 Lenovo
 *
 * Original code from Thinkpad-wmi project https://github.com/iksaif/thinkpad-wmi
 * Copyright(C) 2017 Corentin Chary <corentin.chary@gmail.com>
 * Distributed under the GPL-2.0 license
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/acpi.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/wmi.h>
#include "firmware_attributes_class.h"
#include "think-lmi.h"

static bool debug_support;
module_param(debug_support, bool, 0444);
MODULE_PARM_DESC(debug_support, "Enable debug command support");

/*
 * Name:
 *  Lenovo_BiosSetting
 * Description:
 *  Get item name and settings for current LMI instance.
 * Type:
 *  Query
 * Returns:
 *  "Item,Value"
 * Example:
 *  "WakeOnLAN,Enable"
 */
#define LENOVO_BIOS_SETTING_GUID "51F5230E-9677-46CD-A1CF-C0B23EE34DB7"

/*
 * Name:
 *  Lenovo_SetBiosSetting
 * Description:
 *  Change the BIOS setting to the desired value using the Lenovo_SetBiosSetting
 *  class. To save the settings, use the Lenovo_SaveBiosSetting class.
 *  BIOS settings and values are case sensitive.
 *  After making changes to the BIOS settings, you must reboot the computer
 *  before the changes will take effect.
 * Type:
 *  Method
 * Arguments:
 *  "Item,Value,Password,Encoding,KbdLang;"
 * Example:
 *  "WakeOnLAN,Disable,pa55w0rd,ascii,us;"
 */
#define LENOVO_SET_BIOS_SETTINGS_GUID "98479A64-33F5-4E33-A707-8E251EBBC3A1"

/*
 * Name:
 *  Lenovo_SaveBiosSettings
 * Description:
 *  Save any pending changes in settings.
 * Type:
 *  Method
 * Arguments:
 *  "Password,Encoding,KbdLang;"
 * Example:
 * "pa55w0rd,ascii,us;"
 */
#define LENOVO_SAVE_BIOS_SETTINGS_GUID "6A4B54EF-A5ED-4D33-9455-B0D9B48DF4B3"

/*
 * Name:
 *  Lenovo_BiosPasswordSettings
 * Description:
 *  Return BIOS Password settings
 * Type:
 *  Query
 * Returns:
 *  PasswordMode, PasswordState, MinLength, MaxLength,
 *  SupportedEncoding, SupportedKeyboard
 */
#define LENOVO_BIOS_PASSWORD_SETTINGS_GUID "8ADB159E-1E32-455C-BC93-308A7ED98246"

/*
 * Name:
 *  Lenovo_SetBiosPassword
 * Description:
 *  Change a specific password.
 *  - BIOS settings cannot be changed at the same boot as power-on
 *    passwords (POP) and hard disk passwords (HDP). If you want to change
 *    BIOS settings and POP or HDP, you must reboot the system after changing
 *    one of them.
 *  - A password cannot be set using this method when one does not already
 *    exist. Passwords can only be updated or cleared.
 * Type:
 *  Method
 * Arguments:
 *  "PasswordType,CurrentPassword,NewPassword,Encoding,KbdLang;"
 * Example:
 *  "pop,pa55w0rd,newpa55w0rd,ascii,us;”
 */
#define LENOVO_SET_BIOS_PASSWORD_GUID "2651D9FD-911C-4B69-B94E-D0DED5963BD7"

/*
 * Name:
 *  Lenovo_GetBiosSelections
 * Description:
 *  Return a list of valid settings for a given item.
 * Type:
 *  Method
 * Arguments:
 *  "Item"
 * Returns:
 *  "Value1,Value2,Value3,..."
 * Example:
 *  -> "FlashOverLAN"
 *  <- "Enabled,Disabled"
 */
#define LENOVO_GET_BIOS_SELECTIONS_GUID "7364651A-132F-4FE7-ADAA-40C6C7EE2E3B"

/*
 * Name:
 *  Lenovo_DebugCmdGUID
 * Description
 *  Debug entry GUID method for entering debug commands to the BIOS
 */
#define LENOVO_DEBUG_CMD_GUID "7FF47003-3B6C-4E5E-A227-E979824A85D1"

#define TLMI_POP_PWD (1 << 0)
#define TLMI_PAP_PWD (1 << 1)
#define to_tlmi_pwd_setting(kobj)  container_of(kobj, struct tlmi_pwd_setting, kobj)
#define to_tlmi_attr_setting(kobj)  container_of(kobj, struct tlmi_attr_setting, kobj)

static const struct tlmi_err_codes tlmi_errs[] = {
        {"Success", 0},
        {"Not Supported", -EOPNOTSUPP},
        {"Invalid Parameter", -EINVAL},
        {"Access Denied", -EACCES},
        {"System Busy", -EBUSY},
};

static const char * const encoding_options[] = {
        [TLMI_ENCODING_ASCII] = "ascii",
        [TLMI_ENCODING_SCANCODE] = "scancode",
};
static struct think_lmi tlmi_priv;
static struct class *fw_attr_class;

/* ------ Utility functions ------------*/
/* Convert BIOS WMI error string to suitable error code */
static int tlmi_errstr_to_err(const char *errstr)
{
        int i;

        for (i = 0; i < sizeof(tlmi_errs)/sizeof(struct tlmi_err_codes); i++) {
                if (!strcmp(tlmi_errs[i].err_str, errstr))
                        return tlmi_errs[i].err_code;
        }
        return -EPERM;
}

/* Extract error string from WMI return buffer */
static int tlmi_extract_error(const struct acpi_buffer *output)
{
        const union acpi_object *obj;

        obj = output->pointer;
        if (!obj)
                return -ENOMEM;
        if (obj->type != ACPI_TYPE_STRING || !obj->string.pointer)
                return -EIO;

        return tlmi_errstr_to_err(obj->string.pointer);
}

/* Utility function to execute WMI call to BIOS */
static int tlmi_simple_call(const char *guid, const char *arg)
{
        const struct acpi_buffer input = { strlen(arg), (char *)arg };
        struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
        acpi_status status;
        int i, err;

        /*
         * Duplicated call required to match BIOS workaround for behavior
         * seen when WMI accessed via scripting on other OS.
         */
        for (i = 0; i < 2; i++) {
                /* (re)initialize output buffer to default state */
                output.length = ACPI_ALLOCATE_BUFFER;
                output.pointer = NULL;

                status = wmi_evaluate_method(guid, 0, 0, &input, &output);
                if (ACPI_FAILURE(status)) {
                        kfree(output.pointer);
                        return -EIO;
                }
                err = tlmi_extract_error(&output);
                kfree(output.pointer);
                if (err)
                        return err;
        }
        return 0;
}

/* Extract output string from WMI return buffer */
static int tlmi_extract_output_string(const struct acpi_buffer *output,
                                      char **string)
{
        const union acpi_object *obj;
        char *s;

        obj = output->pointer;
        if (!obj)
                return -ENOMEM;
        if (obj->type != ACPI_TYPE_STRING || !obj->string.pointer)
                return -EIO;

        s = kstrdup(obj->string.pointer, GFP_KERNEL);
        if (!s)
                return -ENOMEM;
        *string = s;
        return 0;
}

/* ------ Core interface functions ------------*/

/* Get password settings from BIOS */
static int tlmi_get_pwd_settings(struct tlmi_pwdcfg *pwdcfg)
{
        struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
        const union acpi_object *obj;
        acpi_status status;

        if (!tlmi_priv.can_get_password_settings)
                return -EOPNOTSUPP;

        status = wmi_query_block(LENOVO_BIOS_PASSWORD_SETTINGS_GUID, 0,
                                 &output);
        if (ACPI_FAILURE(status))
                return -EIO;

        obj = output.pointer;
        if (!obj)
                return -ENOMEM;
        if (obj->type != ACPI_TYPE_BUFFER || !obj->buffer.pointer) {
                kfree(obj);
                return -EIO;
        }
        /*
         * The size of thinkpad_wmi_pcfg on ThinkStation is larger than ThinkPad.
         * To make the driver compatible on different brands, we permit it to get
         * the data in below case.
         */
        if (obj->buffer.length < sizeof(struct tlmi_pwdcfg)) {
                pr_warn("Unknown pwdcfg buffer length %d\n", obj->buffer.length);
                kfree(obj);
                return -EIO;
        }
        memcpy(pwdcfg, obj->buffer.pointer, sizeof(struct tlmi_pwdcfg));
        kfree(obj);
        return 0;
}

static int tlmi_save_bios_settings(const char *password)
{
        return tlmi_simple_call(LENOVO_SAVE_BIOS_SETTINGS_GUID,
                                password);
}

static int tlmi_setting(int item, char **value, const char *guid_string)
{
        struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
        acpi_status status;
        int ret;

        status = wmi_query_block(guid_string, item, &output);
        if (ACPI_FAILURE(status)) {
                kfree(output.pointer);
                return -EIO;
        }

        ret = tlmi_extract_output_string(&output, value);
        kfree(output.pointer);
        return ret;
}

static int tlmi_get_bios_selections(const char *item, char **value)
{
        const struct acpi_buffer input = { strlen(item), (char *)item };
        struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
        acpi_status status;
        int ret;

        status = wmi_evaluate_method(LENOVO_GET_BIOS_SELECTIONS_GUID,
                                     0, 0, &input, &output);

        if (ACPI_FAILURE(status)) {
                kfree(output.pointer);
                return -EIO;
        }

        ret = tlmi_extract_output_string(&output, value);
        kfree(output.pointer);
        return ret;
}

/* ---- Authentication sysfs --------------------------------------------------------- */
static ssize_t is_enabled_show(struct kobject *kobj, struct kobj_attribute *attr,
                                          char *buf)
{
        struct tlmi_pwd_setting *setting = to_tlmi_pwd_setting(kobj);

        return sysfs_emit(buf, "%d\n", setting->valid);
}

static struct kobj_attribute auth_is_pass_set = __ATTR_RO(is_enabled);

static ssize_t current_password_store(struct kobject *kobj,
                                      struct kobj_attribute *attr,
                                      const char *buf, size_t count)
{
        struct tlmi_pwd_setting *setting = to_tlmi_pwd_setting(kobj);
        size_t pwdlen;
        char *p;

        pwdlen = strlen(buf);
        /* pwdlen == 0 is allowed to clear the password */
        if (pwdlen && ((pwdlen < setting->minlen) || (pwdlen > setting->maxlen)))
                return -EINVAL;

        strscpy(setting->password, buf, setting->maxlen);
        /* Strip out CR if one is present, setting password won't work if it is present */
        p = strchrnul(setting->password, '\n');
        *p = '\0';
        return count;
}

static struct kobj_attribute auth_current_password = __ATTR_WO(current_password);

static ssize_t new_password_store(struct kobject *kobj,
                                  struct kobj_attribute *attr,
                                  const char *buf, size_t count)
{
        struct tlmi_pwd_setting *setting = to_tlmi_pwd_setting(kobj);
        char *auth_str, *new_pwd, *p;
        size_t pwdlen;
        int ret;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        if (!tlmi_priv.can_set_bios_password)
                return -EOPNOTSUPP;

        new_pwd = kstrdup(buf, GFP_KERNEL);
        if (!new_pwd)
                return -ENOMEM;

        /* Strip out CR if one is present, setting password won't work if it is present */
        p = strchrnul(new_pwd, '\n');
        *p = '\0';

        pwdlen = strlen(new_pwd);
        /* pwdlen == 0 is allowed to clear the password */
        if (pwdlen && ((pwdlen < setting->minlen) || (pwdlen > setting->maxlen))) {
                ret = -EINVAL;
                goto out;
        }

        /* Format: 'PasswordType,CurrentPw,NewPw,Encoding,KbdLang;' */
        auth_str = kasprintf(GFP_KERNEL, "%s,%s,%s,%s,%s;",
                 setting->pwd_type, setting->password, new_pwd,
                 encoding_options[setting->encoding], setting->kbdlang);
        if (!auth_str) {
                ret = -ENOMEM;
                goto out;
        }
        ret = tlmi_simple_call(LENOVO_SET_BIOS_PASSWORD_GUID, auth_str);
        kfree(auth_str);
out:
        kfree(new_pwd);
        return ret ?: count;
}

static struct kobj_attribute auth_new_password = __ATTR_WO(new_password);

static ssize_t min_password_length_show(struct kobject *kobj, struct kobj_attribute *attr,
                         char *buf)
{
        struct tlmi_pwd_setting *setting = to_tlmi_pwd_setting(kobj);

        return sysfs_emit(buf, "%d\n", setting->minlen);
}

static struct kobj_attribute auth_min_pass_length = __ATTR_RO(min_password_length);

static ssize_t max_password_length_show(struct kobject *kobj, struct kobj_attribute *attr,
                         char *buf)
{
        struct tlmi_pwd_setting *setting = to_tlmi_pwd_setting(kobj);

        return sysfs_emit(buf, "%d\n", setting->maxlen);
}
static struct kobj_attribute auth_max_pass_length = __ATTR_RO(max_password_length);

static ssize_t mechanism_show(struct kobject *kobj, struct kobj_attribute *attr,
                         char *buf)
{
        return sysfs_emit(buf, "password\n");
}
static struct kobj_attribute auth_mechanism = __ATTR_RO(mechanism);

static ssize_t encoding_show(struct kobject *kobj, struct kobj_attribute *attr,
                         char *buf)
{
        struct tlmi_pwd_setting *setting = to_tlmi_pwd_setting(kobj);

        return sysfs_emit(buf, "%s\n", encoding_options[setting->encoding]);
}

static ssize_t encoding_store(struct kobject *kobj,
                                  struct kobj_attribute *attr,
                                  const char *buf, size_t count)
{
        struct tlmi_pwd_setting *setting = to_tlmi_pwd_setting(kobj);
        int i;

        /* Scan for a matching profile */
        i = sysfs_match_string(encoding_options, buf);
        if (i < 0)
                return -EINVAL;

        setting->encoding = i;
        return count;
}

static struct kobj_attribute auth_encoding = __ATTR_RW(encoding);

static ssize_t kbdlang_show(struct kobject *kobj, struct kobj_attribute *attr,
                         char *buf)
{
        struct tlmi_pwd_setting *setting = to_tlmi_pwd_setting(kobj);

        return sysfs_emit(buf, "%s\n", setting->kbdlang);
}

static ssize_t kbdlang_store(struct kobject *kobj,
                                  struct kobj_attribute *attr,
                                  const char *buf, size_t count)
{
        struct tlmi_pwd_setting *setting = to_tlmi_pwd_setting(kobj);
        int length;

        /* Calculate length till '\n' or terminating 0 */
        length = strchrnul(buf, '\n') - buf;
        if (!length || length >= TLMI_LANG_MAXLEN)
                return -EINVAL;

        memcpy(setting->kbdlang, buf, length);
        setting->kbdlang[length] = '\0';
        return count;
}

static struct kobj_attribute auth_kbdlang = __ATTR_RW(kbdlang);

static ssize_t role_show(struct kobject *kobj, struct kobj_attribute *attr,
                         char *buf)
{
        struct tlmi_pwd_setting *setting = to_tlmi_pwd_setting(kobj);

        return sysfs_emit(buf, "%s\n", setting->role);
}
static struct kobj_attribute auth_role = __ATTR_RO(role);

static struct attribute *auth_attrs[] = {
        &auth_is_pass_set.attr,
        &auth_min_pass_length.attr,
        &auth_max_pass_length.attr,
        &auth_current_password.attr,
        &auth_new_password.attr,
        &auth_role.attr,
        &auth_mechanism.attr,
        &auth_encoding.attr,
        &auth_kbdlang.attr,
        NULL
};

static const struct attribute_group auth_attr_group = {
        .attrs = auth_attrs,
};

/* ---- Attributes sysfs --------------------------------------------------------- */
static ssize_t display_name_show(struct kobject *kobj, struct kobj_attribute *attr,
                char *buf)
{
        struct tlmi_attr_setting *setting = to_tlmi_attr_setting(kobj);

        return sysfs_emit(buf, "%s\n", setting->display_name);
}

static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
        struct tlmi_attr_setting *setting = to_tlmi_attr_setting(kobj);
        char *item, *value;
        int ret;

        ret = tlmi_setting(setting->index, &item, LENOVO_BIOS_SETTING_GUID);
        if (ret)
                return ret;

        /* validate and split from `item,value` -> `value` */
        value = strpbrk(item, ",");
        if (!value || value == item || !strlen(value + 1))
                return -EINVAL;

        ret = sysfs_emit(buf, "%s\n", value + 1);
        kfree(item);
        return ret;
}

static ssize_t possible_values_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
        struct tlmi_attr_setting *setting = to_tlmi_attr_setting(kobj);

        if (!tlmi_priv.can_get_bios_selections)
                return -EOPNOTSUPP;

        return sysfs_emit(buf, "%s\n", setting->possible_values);
}

static ssize_t current_value_store(struct kobject *kobj,
                struct kobj_attribute *attr,
                const char *buf, size_t count)
{
        struct tlmi_attr_setting *setting = to_tlmi_attr_setting(kobj);
        char *set_str = NULL, *new_setting = NULL;
        char *auth_str = NULL;
        char *p;
        int ret;

        if (!tlmi_priv.can_set_bios_settings)
                return -EOPNOTSUPP;

        new_setting = kstrdup(buf, GFP_KERNEL);
        if (!new_setting)
                return -ENOMEM;

        /* Strip out CR if one is present */
        p = strchrnul(new_setting, '\n');
        *p = '\0';

        if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password[0]) {
                auth_str = kasprintf(GFP_KERNEL, "%s,%s,%s;",
                                tlmi_priv.pwd_admin->password,
                                encoding_options[tlmi_priv.pwd_admin->encoding],
                                tlmi_priv.pwd_admin->kbdlang);
                if (!auth_str) {
                        ret = -ENOMEM;
                        goto out;
                }
        }

        if (auth_str)
                set_str = kasprintf(GFP_KERNEL, "%s,%s,%s", setting->display_name,
                                new_setting, auth_str);
        else
                set_str = kasprintf(GFP_KERNEL, "%s,%s;", setting->display_name,
                                new_setting);
        if (!set_str) {
                ret = -ENOMEM;
                goto out;
        }

        ret = tlmi_simple_call(LENOVO_SET_BIOS_SETTINGS_GUID, set_str);
        if (ret)
                goto out;

        if (auth_str)
                ret = tlmi_save_bios_settings(auth_str);
        else
                ret = tlmi_save_bios_settings("");

        if (!ret && !tlmi_priv.pending_changes) {
                tlmi_priv.pending_changes = true;
                /* let userland know it may need to check reboot pending again */
                kobject_uevent(&tlmi_priv.class_dev->kobj, KOBJ_CHANGE);
        }
out:
        kfree(auth_str);
        kfree(set_str);
        kfree(new_setting);
        return ret ?: count;
}

static struct kobj_attribute attr_displ_name = __ATTR_RO(display_name);

static struct kobj_attribute attr_possible_values = __ATTR_RO(possible_values);

static struct kobj_attribute attr_current_val = __ATTR_RW_MODE(current_value, 0600);

static struct attribute *tlmi_attrs[] = {
        &attr_displ_name.attr,
        &attr_current_val.attr,
        &attr_possible_values.attr,
        NULL
};

static const struct attribute_group tlmi_attr_group = {
        .attrs = tlmi_attrs,
};

static ssize_t tlmi_attr_show(struct kobject *kobj, struct attribute *attr,
                                    char *buf)
{
        struct kobj_attribute *kattr;

        kattr = container_of(attr, struct kobj_attribute, attr);
        if (kattr->show)
                return kattr->show(kobj, kattr, buf);
        return -EIO;
}

static ssize_t tlmi_attr_store(struct kobject *kobj, struct attribute *attr,
                                     const char *buf, size_t count)
{
        struct kobj_attribute *kattr;

        kattr = container_of(attr, struct kobj_attribute, attr);
        if (kattr->store)
                return kattr->store(kobj, kattr, buf, count);
        return -EIO;
}

static const struct sysfs_ops tlmi_kobj_sysfs_ops = {
        .show   = tlmi_attr_show,
        .store  = tlmi_attr_store,
};

static void tlmi_attr_setting_release(struct kobject *kobj)
{
        struct tlmi_attr_setting *setting = to_tlmi_attr_setting(kobj);

        kfree(setting->possible_values);
        kfree(setting);
}

static void tlmi_pwd_setting_release(struct kobject *kobj)
{
        struct tlmi_pwd_setting *setting = to_tlmi_pwd_setting(kobj);

        kfree(setting);
}

static struct kobj_type tlmi_attr_setting_ktype = {
        .release        = &tlmi_attr_setting_release,
        .sysfs_ops      = &tlmi_kobj_sysfs_ops,
};

static struct kobj_type tlmi_pwd_setting_ktype = {
        .release        = &tlmi_pwd_setting_release,
        .sysfs_ops      = &tlmi_kobj_sysfs_ops,
};

static ssize_t pending_reboot_show(struct kobject *kobj, struct kobj_attribute *attr,
                                   char *buf)
{
        return sprintf(buf, "%d\n", tlmi_priv.pending_changes);
}

static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot);

/* ---- Debug interface--------------------------------------------------------- */
static ssize_t debug_cmd_store(struct kobject *kobj, struct kobj_attribute *attr,
                                const char *buf, size_t count)
{
        char *set_str = NULL, *new_setting = NULL;
        char *auth_str = NULL;
        char *p;
        int ret;

        if (!tlmi_priv.can_debug_cmd)
                return -EOPNOTSUPP;

        new_setting = kstrdup(buf, GFP_KERNEL);
        if (!new_setting)
                return -ENOMEM;

        /* Strip out CR if one is present */
        p = strchrnul(new_setting, '\n');
        *p = '\0';

        if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password[0]) {
                auth_str = kasprintf(GFP_KERNEL, "%s,%s,%s;",
                                tlmi_priv.pwd_admin->password,
                                encoding_options[tlmi_priv.pwd_admin->encoding],
                                tlmi_priv.pwd_admin->kbdlang);
                if (!auth_str) {
                        ret = -ENOMEM;
                        goto out;
                }
        }

        if (auth_str)
                set_str = kasprintf(GFP_KERNEL, "%s,%s", new_setting, auth_str);
        else
                set_str = kasprintf(GFP_KERNEL, "%s;", new_setting);
        if (!set_str) {
                ret = -ENOMEM;
                goto out;
        }

        ret = tlmi_simple_call(LENOVO_DEBUG_CMD_GUID, set_str);
        if (ret)
                goto out;

        if (!ret && !tlmi_priv.pending_changes) {
                tlmi_priv.pending_changes = true;
                /* let userland know it may need to check reboot pending again */
                kobject_uevent(&tlmi_priv.class_dev->kobj, KOBJ_CHANGE);
        }
out:
        kfree(auth_str);
        kfree(set_str);
        kfree(new_setting);
        return ret ?: count;
}

static struct kobj_attribute debug_cmd = __ATTR_WO(debug_cmd);

/* ---- Initialisation --------------------------------------------------------- */
static void tlmi_release_attr(void)
{
        int i;

        /* Attribute structures */
        for (i = 0; i < TLMI_SETTINGS_COUNT; i++) {
                if (tlmi_priv.setting[i]) {
                        sysfs_remove_group(&tlmi_priv.setting[i]->kobj, &tlmi_attr_group);
                        kobject_put(&tlmi_priv.setting[i]->kobj);
                }
        }
        sysfs_remove_file(&tlmi_priv.attribute_kset->kobj, &pending_reboot.attr);
        if (tlmi_priv.can_debug_cmd && debug_support)
                sysfs_remove_file(&tlmi_priv.attribute_kset->kobj, &debug_cmd.attr);
        kset_unregister(tlmi_priv.attribute_kset);

        /* Authentication structures */
        sysfs_remove_group(&tlmi_priv.pwd_admin->kobj, &auth_attr_group);
        kobject_put(&tlmi_priv.pwd_admin->kobj);
        sysfs_remove_group(&tlmi_priv.pwd_power->kobj, &auth_attr_group);
        kobject_put(&tlmi_priv.pwd_power->kobj);
        kset_unregister(tlmi_priv.authentication_kset);
}

static int tlmi_sysfs_init(void)
{
        int i, ret;

        ret = fw_attributes_class_get(&fw_attr_class);
        if (ret)
                return ret;

        tlmi_priv.class_dev = device_create(fw_attr_class, NULL, MKDEV(0, 0),
                        NULL, "%s", "thinklmi");
        if (IS_ERR(tlmi_priv.class_dev)) {
                ret = PTR_ERR(tlmi_priv.class_dev);
                goto fail_class_created;
        }

        tlmi_priv.attribute_kset = kset_create_and_add("attributes", NULL,
                        &tlmi_priv.class_dev->kobj);
        if (!tlmi_priv.attribute_kset) {
                ret = -ENOMEM;
                goto fail_device_created;
        }

        for (i = 0; i < TLMI_SETTINGS_COUNT; i++) {
                /* Check if index is a valid setting - skip if it isn't */
                if (!tlmi_priv.setting[i])
                        continue;

                /* check for duplicate or reserved values */
                if (kset_find_obj(tlmi_priv.attribute_kset, tlmi_priv.setting[i]->display_name) ||
                    !strcmp(tlmi_priv.setting[i]->display_name, "Reserved")) {
                        pr_debug("duplicate or reserved attribute name found - %s\n",
                                tlmi_priv.setting[i]->display_name);
                        kfree(tlmi_priv.setting[i]->possible_values);
                        kfree(tlmi_priv.setting[i]);
                        tlmi_priv.setting[i] = NULL;
                        continue;
                }

                /* Build attribute */
                tlmi_priv.setting[i]->kobj.kset = tlmi_priv.attribute_kset;
                ret = kobject_add(&tlmi_priv.setting[i]->kobj, NULL,
                                  "%s", tlmi_priv.setting[i]->display_name);
                if (ret)
                        goto fail_create_attr;

                ret = sysfs_create_group(&tlmi_priv.setting[i]->kobj, &tlmi_attr_group);
                if (ret)
                        goto fail_create_attr;
        }

        ret = sysfs_create_file(&tlmi_priv.attribute_kset->kobj, &pending_reboot.attr);
        if (ret)
                goto fail_create_attr;

        if (tlmi_priv.can_debug_cmd && debug_support) {
                ret = sysfs_create_file(&tlmi_priv.attribute_kset->kobj, &debug_cmd.attr);
                if (ret)
                        goto fail_create_attr;
        }
        /* Create authentication entries */
        tlmi_priv.authentication_kset = kset_create_and_add("authentication", NULL,
                                                                &tlmi_priv.class_dev->kobj);
        if (!tlmi_priv.authentication_kset) {
                ret = -ENOMEM;
                goto fail_create_attr;
        }
        tlmi_priv.pwd_admin->kobj.kset = tlmi_priv.authentication_kset;
        ret = kobject_add(&tlmi_priv.pwd_admin->kobj, NULL, "%s", "Admin");
        if (ret)
                goto fail_create_attr;

        ret = sysfs_create_group(&tlmi_priv.pwd_admin->kobj, &auth_attr_group);
        if (ret)
                goto fail_create_attr;

        tlmi_priv.pwd_power->kobj.kset = tlmi_priv.authentication_kset;
        ret = kobject_add(&tlmi_priv.pwd_power->kobj, NULL, "%s", "System");
        if (ret)
                goto fail_create_attr;

        ret = sysfs_create_group(&tlmi_priv.pwd_power->kobj, &auth_attr_group);
        if (ret)
                goto fail_create_attr;

        return ret;

fail_create_attr:
        tlmi_release_attr();
fail_device_created:
        device_destroy(fw_attr_class, MKDEV(0, 0));
fail_class_created:
        fw_attributes_class_put();
        return ret;
}

/* ---- Base Driver -------------------------------------------------------- */
static int tlmi_analyze(void)
{
        struct tlmi_pwdcfg pwdcfg;
        acpi_status status;
        int i, ret;

        if (wmi_has_guid(LENOVO_SET_BIOS_SETTINGS_GUID) &&
            wmi_has_guid(LENOVO_SAVE_BIOS_SETTINGS_GUID))
                tlmi_priv.can_set_bios_settings = true;

        if (wmi_has_guid(LENOVO_GET_BIOS_SELECTIONS_GUID))
                tlmi_priv.can_get_bios_selections = true;

        if (wmi_has_guid(LENOVO_SET_BIOS_PASSWORD_GUID))
                tlmi_priv.can_set_bios_password = true;

        if (wmi_has_guid(LENOVO_BIOS_PASSWORD_SETTINGS_GUID))
                tlmi_priv.can_get_password_settings = true;

        if (wmi_has_guid(LENOVO_DEBUG_CMD_GUID))
                tlmi_priv.can_debug_cmd = true;

        /*
         * Try to find the number of valid settings of this machine
         * and use it to create sysfs attributes.
         */
        for (i = 0; i < TLMI_SETTINGS_COUNT; ++i) {
                struct tlmi_attr_setting *setting;
                char *item = NULL;
                char *p;

                tlmi_priv.setting[i] = NULL;
                status = tlmi_setting(i, &item, LENOVO_BIOS_SETTING_GUID);
                if (ACPI_FAILURE(status))
                        break;
                if (!item)
                        break;
                if (!*item)
                        continue;

                /* It is not allowed to have '/' for file name. Convert it into '\'. */
                strreplace(item, '/', '\\');

                /* Remove the value part */
                p = strchrnul(item, ',');
                *p = '\0';

                /* Create a setting entry */
                setting = kzalloc(sizeof(*setting), GFP_KERNEL);
                if (!setting) {
                        ret = -ENOMEM;
                        goto fail_clear_attr;
                }
                setting->index = i;
                strscpy(setting->display_name, item, TLMI_SETTINGS_MAXLEN);
                /* If BIOS selections supported, load those */
                if (tlmi_priv.can_get_bios_selections) {
                        ret = tlmi_get_bios_selections(setting->display_name,
                                        &setting->possible_values);
                        if (ret || !setting->possible_values)
                                pr_info("Error retrieving possible values for %d : %s\n",
                                                i, setting->display_name);
                }
                kobject_init(&setting->kobj, &tlmi_attr_setting_ktype);
                tlmi_priv.setting[i] = setting;
                tlmi_priv.settings_count++;
                kfree(item);
        }

        /* Create password setting structure */
        ret = tlmi_get_pwd_settings(&pwdcfg);
        if (ret)
                goto fail_clear_attr;

        tlmi_priv.pwd_admin = kzalloc(sizeof(struct tlmi_pwd_setting), GFP_KERNEL);
        if (!tlmi_priv.pwd_admin) {
                ret = -ENOMEM;
                goto fail_clear_attr;
        }
        strscpy(tlmi_priv.pwd_admin->kbdlang, "us", TLMI_LANG_MAXLEN);
        tlmi_priv.pwd_admin->encoding = TLMI_ENCODING_ASCII;
        tlmi_priv.pwd_admin->pwd_type = "pap";
        tlmi_priv.pwd_admin->role = "bios-admin";
        tlmi_priv.pwd_admin->minlen = pwdcfg.min_length;
        if (WARN_ON(pwdcfg.max_length >= TLMI_PWD_BUFSIZE))
                pwdcfg.max_length = TLMI_PWD_BUFSIZE - 1;
        tlmi_priv.pwd_admin->maxlen = pwdcfg.max_length;
        if (pwdcfg.password_state & TLMI_PAP_PWD)
                tlmi_priv.pwd_admin->valid = true;

        kobject_init(&tlmi_priv.pwd_admin->kobj, &tlmi_pwd_setting_ktype);

        tlmi_priv.pwd_power = kzalloc(sizeof(struct tlmi_pwd_setting), GFP_KERNEL);
        if (!tlmi_priv.pwd_power) {
                ret = -ENOMEM;
                goto fail_free_pwd_admin;
        }
        strscpy(tlmi_priv.pwd_power->kbdlang, "us", TLMI_LANG_MAXLEN);
        tlmi_priv.pwd_power->encoding = TLMI_ENCODING_ASCII;
        tlmi_priv.pwd_power->pwd_type = "pop";
        tlmi_priv.pwd_power->role = "power-on";
        tlmi_priv.pwd_power->minlen = pwdcfg.min_length;
        tlmi_priv.pwd_power->maxlen = pwdcfg.max_length;

        if (pwdcfg.password_state & TLMI_POP_PWD)
                tlmi_priv.pwd_power->valid = true;

        kobject_init(&tlmi_priv.pwd_power->kobj, &tlmi_pwd_setting_ktype);

        return 0;

fail_free_pwd_admin:
        kfree(tlmi_priv.pwd_admin);
fail_clear_attr:
        for (i = 0; i < TLMI_SETTINGS_COUNT; ++i) {
                if (tlmi_priv.setting[i]) {
                        kfree(tlmi_priv.setting[i]->possible_values);
                        kfree(tlmi_priv.setting[i]);
                }
        }
        return ret;
}

static void tlmi_remove(struct wmi_device *wdev)
{
        tlmi_release_attr();
        device_destroy(fw_attr_class, MKDEV(0, 0));
        fw_attributes_class_put();
}

static int tlmi_probe(struct wmi_device *wdev, const void *context)
{
        tlmi_analyze();
        return tlmi_sysfs_init();
}

static const struct wmi_device_id tlmi_id_table[] = {
        { .guid_string = LENOVO_BIOS_SETTING_GUID },
        { }
};
MODULE_DEVICE_TABLE(wmi, tlmi_id_table);

static struct wmi_driver tlmi_driver = {
        .driver = {
                .name = "think-lmi",
        },
        .id_table = tlmi_id_table,

        .probe = tlmi_probe,
        .remove = tlmi_remove,
};

MODULE_AUTHOR("Sugumaran L <slacshiminar@lenovo.com>");
MODULE_AUTHOR("Mark Pearson <markpearson@lenovo.com>");
MODULE_AUTHOR("Corentin Chary <corentin.chary@gmail.com>");
MODULE_DESCRIPTION("ThinkLMI Driver");
MODULE_LICENSE("GPL");

module_wmi_driver(tlmi_driver);