// SPDX-License-Identifier: GPL-2.0
/*
 * Functions corresponding to enumeration type attributes under
 * BIOS Enumeration GUID for use with hp-bioscfg driver.
 *
 * Copyright (c) 2022 HP Development Company, L.P.
 */

#include "bioscfg.h"

GET_INSTANCE_ID(enumeration);

static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
        int instance_id = get_enumeration_instance_id(kobj);

        if (instance_id < 0)
                return -EIO;

        return sysfs_emit(buf, "%s\n",
                         bioscfg_drv.enumeration_data[instance_id].current_value);
}

/**
 * validate_enumeration_input() -
 * Validate input of current_value against possible values
 *
 * @instance_id: The instance on which input is validated
 * @buf: Input value
 */
static int validate_enumeration_input(int instance_id, const char *buf)
{
        int i;
        int found = 0;
        struct enumeration_data *enum_data = &bioscfg_drv.enumeration_data[instance_id];

        /* Is it a read only attribute */
        if (enum_data->common.is_readonly)
                return -EIO;

        for (i = 0; i < enum_data->possible_values_size && !found; i++)
                if (!strcmp(enum_data->possible_values[i], buf))
                        found = 1;

        if (!found)
                return -EINVAL;

        return 0;
}

static void update_enumeration_value(int instance_id, char *attr_value)
{
        struct enumeration_data *enum_data = &bioscfg_drv.enumeration_data[instance_id];

        strscpy(enum_data->current_value, attr_value);
}

ATTRIBUTE_S_COMMON_PROPERTY_SHOW(display_name, enumeration);
static struct kobj_attribute enumeration_display_name =
                __ATTR_RO(display_name);

ATTRIBUTE_PROPERTY_STORE(current_value, enumeration);
static struct kobj_attribute enumeration_current_val =
                __ATTR_RW(current_value);

ATTRIBUTE_VALUES_PROPERTY_SHOW(possible_values, enumeration, SEMICOLON_SEP);
static struct kobj_attribute enumeration_poss_val =
                __ATTR_RO(possible_values);

static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr,
                         char *buf)
{
        return sysfs_emit(buf, "enumeration\n");
}

static struct kobj_attribute enumeration_type =
                __ATTR_RO(type);

static struct attribute *enumeration_attrs[] = {
        &common_display_langcode.attr,
        &enumeration_display_name.attr,
        &enumeration_current_val.attr,
        &enumeration_poss_val.attr,
        &enumeration_type.attr,
        NULL
};

static const struct attribute_group enumeration_attr_group = {
        .attrs = enumeration_attrs,
};

int hp_alloc_enumeration_data(void)
{
        bioscfg_drv.enumeration_instances_count =
                hp_get_instance_count(HP_WMI_BIOS_ENUMERATION_GUID);

        if (!bioscfg_drv.enumeration_instances_count)
                return -EINVAL;
        bioscfg_drv.enumeration_data = kvcalloc(bioscfg_drv.enumeration_instances_count,
                                                sizeof(*bioscfg_drv.enumeration_data), GFP_KERNEL);

        if (!bioscfg_drv.enumeration_data) {
                bioscfg_drv.enumeration_instances_count = 0;
                return -ENOMEM;
        }
        return 0;
}

/* Expected Values types associated with each element */
static const acpi_object_type expected_enum_types[] = {
        [NAME] = ACPI_TYPE_STRING,
        [VALUE] = ACPI_TYPE_STRING,
        [PATH] = ACPI_TYPE_STRING,
        [IS_READONLY] = ACPI_TYPE_INTEGER,
        [DISPLAY_IN_UI] = ACPI_TYPE_INTEGER,
        [REQUIRES_PHYSICAL_PRESENCE] = ACPI_TYPE_INTEGER,
        [SEQUENCE] = ACPI_TYPE_INTEGER,
        [PREREQUISITES_SIZE] = ACPI_TYPE_INTEGER,
        [PREREQUISITES] = ACPI_TYPE_STRING,
        [SECURITY_LEVEL] = ACPI_TYPE_INTEGER,
        [ENUM_CURRENT_VALUE] = ACPI_TYPE_STRING,
        [ENUM_SIZE] = ACPI_TYPE_INTEGER,
        [ENUM_POSSIBLE_VALUES] = ACPI_TYPE_STRING,
};

static int hp_populate_enumeration_elements_from_package(union acpi_object *enum_obj,
                                                         int enum_obj_count,
                                                         int instance_id)
{
        char *str_value = NULL;
        int value_len;
        u32 size = 0;
        u32 int_value = 0;
        int elem = 0;
        int reqs;
        int pos_values;
        int ret;
        int eloc;
        struct enumeration_data *enum_data = &bioscfg_drv.enumeration_data[instance_id];

        for (elem = 1, eloc = 1; elem < enum_obj_count; elem++, eloc++) {
                /* ONLY look at the first ENUM_ELEM_CNT elements */
                if (eloc == ENUM_ELEM_CNT)
                        goto exit_enumeration_package;

                switch (enum_obj[elem].type) {
                case ACPI_TYPE_STRING:
                        if (PREREQUISITES != elem && ENUM_POSSIBLE_VALUES != elem) {
                                ret = hp_convert_hexstr_to_str(enum_obj[elem].string.pointer,
                                                               enum_obj[elem].string.length,
                                                               &str_value, &value_len);
                                if (ret)
                                        return -EINVAL;
                        }
                        break;
                case ACPI_TYPE_INTEGER:
                        int_value = (u32)enum_obj[elem].integer.value;
                        break;
                default:
                        pr_warn("Unsupported object type [%d]\n", enum_obj[elem].type);
                        continue;
                }

                /* Check that both expected and read object type match */
                if (expected_enum_types[eloc] != enum_obj[elem].type) {
                        pr_err("Error expected type %d for elem %d, but got type %d instead\n",
                               expected_enum_types[eloc], elem, enum_obj[elem].type);
                        kfree(str_value);
                        return -EIO;
                }

                /* Assign appropriate element value to corresponding field */
                switch (eloc) {
                case NAME:
                case VALUE:
                        break;
                case PATH:
                        strscpy(enum_data->common.path, str_value);
                        break;
                case IS_READONLY:
                        enum_data->common.is_readonly = int_value;
                        break;
                case DISPLAY_IN_UI:
                        enum_data->common.display_in_ui = int_value;
                        break;
                case REQUIRES_PHYSICAL_PRESENCE:
                        enum_data->common.requires_physical_presence = int_value;
                        break;
                case SEQUENCE:
                        enum_data->common.sequence = int_value;
                        break;
                case PREREQUISITES_SIZE:
                        if (int_value > MAX_PREREQUISITES_SIZE) {
                                pr_warn("Prerequisites size value exceeded the maximum number of elements supported or data may be malformed\n");
                                int_value = MAX_PREREQUISITES_SIZE;
                        }
                        enum_data->common.prerequisites_size = int_value;

                        /*
                         * This step is needed to keep the expected
                         * element list pointing to the right obj[elem].type
                         * when the size is zero. PREREQUISITES
                         * object is omitted by BIOS when the size is
                         * zero.
                         */
                        if (int_value == 0)
                                eloc++;
                        break;

                case PREREQUISITES:
                        size = min_t(u32, enum_data->common.prerequisites_size, MAX_PREREQUISITES_SIZE);
                        for (reqs = 0; reqs < size; reqs++) {
                                if (elem + reqs >= enum_obj_count) {
                                        pr_err("Error enum-objects package is too small\n");
                                        return -EINVAL;
                                }

                                ret = hp_convert_hexstr_to_str(enum_obj[elem + reqs].string.pointer,
                                                               enum_obj[elem + reqs].string.length,
                                                               &str_value, &value_len);

                                if (ret)
                                        return -EINVAL;

                                strscpy(enum_data->common.prerequisites[reqs], str_value);

                                kfree(str_value);
                                str_value = NULL;
                        }
                        break;

                case SECURITY_LEVEL:
                        enum_data->common.security_level = int_value;
                        break;

                case ENUM_CURRENT_VALUE:
                        strscpy(enum_data->current_value, str_value);
                        break;
                case ENUM_SIZE:
                        if (int_value > MAX_VALUES_SIZE) {
                                pr_warn("Possible number values size value exceeded the maximum number of elements supported or data may be malformed\n");
                                int_value = MAX_VALUES_SIZE;
                        }
                        enum_data->possible_values_size = int_value;

                        /*
                         * This step is needed to keep the expected
                         * element list pointing to the right obj[elem].type
                         * when the size is zero. POSSIBLE_VALUES
                         * object is omitted by BIOS when the size is zero.
                         */
                        if (int_value == 0)
                                eloc++;
                        break;

                case ENUM_POSSIBLE_VALUES:
                        size = enum_data->possible_values_size;

                        for (pos_values = 0; pos_values < size && pos_values < MAX_VALUES_SIZE;
                             pos_values++) {
                                if (elem + pos_values >= enum_obj_count) {
                                        pr_err("Error enum-objects package is too small\n");
                                        return -EINVAL;
                                }

                                ret = hp_convert_hexstr_to_str(enum_obj[elem + pos_values].string.pointer,
                                                               enum_obj[elem + pos_values].string.length,
                                                               &str_value, &value_len);

                                if (ret)
                                        return -EINVAL;

                                /*
                                 * ignore strings when possible values size
                                 * is greater than MAX_VALUES_SIZE
                                 */
                                if (size < MAX_VALUES_SIZE)
                                        strscpy(enum_data->possible_values[pos_values], str_value);

                                kfree(str_value);
                                str_value = NULL;
                        }
                        break;
                default:
                        pr_warn("Invalid element: %d found in Enumeration attribute or data may be malformed\n", elem);
                        break;
                }

                kfree(str_value);
                str_value = NULL;
        }

exit_enumeration_package:
        kfree(str_value);
        return 0;
}

/**
 * hp_populate_enumeration_package_data() -
 * Populate all properties of an instance under enumeration attribute
 *
 * @enum_obj: ACPI object with enumeration data
 * @instance_id: The instance to enumerate
 * @attr_name_kobj: The parent kernel object
 */
int hp_populate_enumeration_package_data(union acpi_object *enum_obj,
                                         int instance_id,
                                         struct kobject *attr_name_kobj)
{
        struct enumeration_data *enum_data = &bioscfg_drv.enumeration_data[instance_id];

        enum_data->attr_name_kobj = attr_name_kobj;

        hp_populate_enumeration_elements_from_package(enum_obj,
                                                      enum_obj->package.count,
                                                      instance_id);
        hp_update_attribute_permissions(enum_data->common.is_readonly,
                                        &enumeration_current_val);
        /*
         * Several attributes have names such "MONDAY". Friendly
         * user nane is generated to make the name more descriptive
         */
        hp_friendly_user_name_update(enum_data->common.path,
                                     attr_name_kobj->name,
                                     enum_data->common.display_name,
                                     sizeof(enum_data->common.display_name));
        return sysfs_create_group(attr_name_kobj, &enumeration_attr_group);
}

static int hp_populate_enumeration_elements_from_buffer(u8 *buffer_ptr, u32 *buffer_size,
                                                        int instance_id)
{
        int values;
        struct enumeration_data *enum_data = &bioscfg_drv.enumeration_data[instance_id];
        int ret = 0;

        /*
         * Only data relevant to this driver and its functionality is
         * read. BIOS defines the order in which each * element is
         * read. Element 0 data is not relevant to this
         * driver hence it is ignored. For clarity, all element names
         * (DISPLAY_IN_UI) which defines the order in which is read
         * and the name matches the variable where the data is stored.
         *
         * In earlier implementation, reported errors were ignored
         * causing the data to remain uninitialized. It is not
         * possible to determine if data read from BIOS is valid or
         * not. It is for this reason functions may return a error
         * without validating the data itself.
         */

        // VALUE:
        ret = hp_get_string_from_buffer(&buffer_ptr, buffer_size, enum_data->current_value,
                                        sizeof(enum_data->current_value));
        if (ret < 0)
                goto buffer_exit;

        // COMMON:
        ret = hp_get_common_data_from_buffer(&buffer_ptr, buffer_size, &enum_data->common);
        if (ret < 0)
                goto buffer_exit;

        // ENUM_CURRENT_VALUE:
        ret = hp_get_string_from_buffer(&buffer_ptr, buffer_size,
                                        enum_data->current_value,
                                        sizeof(enum_data->current_value));
        if (ret < 0)
                goto buffer_exit;

        // ENUM_SIZE:
        ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
                                         &enum_data->possible_values_size);

        if (enum_data->possible_values_size > MAX_VALUES_SIZE) {
                /* Report a message and limit possible values size to maximum value */
                pr_warn("Enum Possible size value exceeded the maximum number of elements supported or data may be malformed\n");
                enum_data->possible_values_size = MAX_VALUES_SIZE;
        }

        // ENUM_POSSIBLE_VALUES:
        for (values = 0; values < enum_data->possible_values_size; values++) {
                ret = hp_get_string_from_buffer(&buffer_ptr, buffer_size,
                                                enum_data->possible_values[values],
                                                sizeof(enum_data->possible_values[values]));
                if (ret < 0)
                        break;
        }

buffer_exit:
        return ret;
}

/**
 * hp_populate_enumeration_buffer_data() -
 * Populate all properties of an instance under enumeration attribute
 *
 * @buffer_ptr: Buffer pointer
 * @buffer_size: Buffer size
 * @instance_id: The instance to enumerate
 * @attr_name_kobj: The parent kernel object
 */
int hp_populate_enumeration_buffer_data(u8 *buffer_ptr, u32 *buffer_size,
                                        int instance_id,
                                        struct kobject *attr_name_kobj)
{
        struct enumeration_data *enum_data = &bioscfg_drv.enumeration_data[instance_id];
        int ret = 0;

        enum_data->attr_name_kobj = attr_name_kobj;

        /* Populate enumeration elements */
        ret = hp_populate_enumeration_elements_from_buffer(buffer_ptr, buffer_size,
                                                           instance_id);
        if (ret < 0)
                return ret;

        hp_update_attribute_permissions(enum_data->common.is_readonly,
                                        &enumeration_current_val);
        /*
         * Several attributes have names such "MONDAY". A Friendlier
         * user nane is generated to make the name more descriptive
         */
        hp_friendly_user_name_update(enum_data->common.path,
                                     attr_name_kobj->name,
                                     enum_data->common.display_name,
                                     sizeof(enum_data->common.display_name));

        return sysfs_create_group(attr_name_kobj, &enumeration_attr_group);
}

/**
 * hp_exit_enumeration_attributes() - Clear all attribute data
 *
 * Clears all data allocated for this group of attributes
 */
void hp_exit_enumeration_attributes(void)
{
        int instance_id;

        for (instance_id = 0; instance_id < bioscfg_drv.enumeration_instances_count;
             instance_id++) {
                struct enumeration_data *enum_data = &bioscfg_drv.enumeration_data[instance_id];
                struct kobject *attr_name_kobj = enum_data->attr_name_kobj;

                if (attr_name_kobj)
                        sysfs_remove_group(attr_name_kobj, &enumeration_attr_group);
        }
        bioscfg_drv.enumeration_instances_count = 0;

        kvfree(bioscfg_drv.enumeration_data);
        bioscfg_drv.enumeration_data = NULL;
}