// SPDX-License-Identifier: GPL-2.0
/*
 * Functions corresponding to integer type attributes under
 * BIOS Enumeration GUID for use with hp-bioscfg driver.
 *
 * Copyright (c) 2022 Hewlett-Packard Inc.
 */

#include "bioscfg.h"

GET_INSTANCE_ID(integer);

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

        if (instance_id < 0)
                return -EIO;

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

/**
 * validate_integer_input() -
 * Validate input of current_value against lower and upper bound
 *
 * @instance_id: The instance on which input is validated
 * @buf: Input value
 */
static int validate_integer_input(int instance_id, char *buf)
{
        int in_val;
        int ret;
        struct integer_data *integer_data = &bioscfg_drv.integer_data[instance_id];

        /* BIOS treats it as a read only attribute */
        if (integer_data->common.is_readonly)
                return -EIO;

        ret = kstrtoint(buf, 10, &in_val);
        if (ret < 0)
                return ret;

        if (in_val < integer_data->lower_bound ||
            in_val > integer_data->upper_bound)
                return -ERANGE;

        return 0;
}

static void update_integer_value(int instance_id, char *attr_value)
{
        int in_val;
        int ret;
        struct integer_data *integer_data = &bioscfg_drv.integer_data[instance_id];

        ret = kstrtoint(attr_value, 10, &in_val);
        if (ret == 0)
                integer_data->current_value = in_val;
        else
                pr_warn("Invalid integer value found: %s\n", attr_value);
}

ATTRIBUTE_S_COMMON_PROPERTY_SHOW(display_name, integer);
static struct kobj_attribute integer_display_name =
        __ATTR_RO(display_name);

ATTRIBUTE_PROPERTY_STORE(current_value, integer);
static struct kobj_attribute integer_current_val =
        __ATTR_RW_MODE(current_value, 0644);

ATTRIBUTE_N_PROPERTY_SHOW(lower_bound, integer);
static struct kobj_attribute integer_lower_bound =
        __ATTR_RO(lower_bound);

ATTRIBUTE_N_PROPERTY_SHOW(upper_bound, integer);
static struct kobj_attribute integer_upper_bound =
        __ATTR_RO(upper_bound);

ATTRIBUTE_N_PROPERTY_SHOW(scalar_increment, integer);
static struct kobj_attribute integer_scalar_increment =
        __ATTR_RO(scalar_increment);

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

static struct kobj_attribute integer_type =
        __ATTR_RO(type);

static struct attribute *integer_attrs[] = {
        &common_display_langcode.attr,
        &integer_display_name.attr,
        &integer_current_val.attr,
        &integer_lower_bound.attr,
        &integer_upper_bound.attr,
        &integer_scalar_increment.attr,
        &integer_type.attr,
        NULL
};

static const struct attribute_group integer_attr_group = {
        .attrs = integer_attrs,
};

int hp_alloc_integer_data(void)
{
        bioscfg_drv.integer_instances_count = hp_get_instance_count(HP_WMI_BIOS_INTEGER_GUID);
        bioscfg_drv.integer_data = kzalloc_objs(*bioscfg_drv.integer_data,
                                                bioscfg_drv.integer_instances_count);

        if (!bioscfg_drv.integer_data) {
                bioscfg_drv.integer_instances_count = 0;
                return -ENOMEM;
        }
        return 0;
}

/* Expected Values types associated with each element */
static const acpi_object_type expected_integer_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,
        [INT_LOWER_BOUND] = ACPI_TYPE_INTEGER,
        [INT_UPPER_BOUND] = ACPI_TYPE_INTEGER,
        [INT_SCALAR_INCREMENT] = ACPI_TYPE_INTEGER,
};

static int hp_populate_integer_elements_from_package(union acpi_object *integer_obj,
                                                     int integer_obj_count,
                                                     int instance_id)
{
        char *str_value = NULL;
        int value_len;
        int ret;
        u32 int_value = 0;
        int elem;
        int reqs;
        int eloc;
        int size;
        struct integer_data *integer_data = &bioscfg_drv.integer_data[instance_id];

        if (!integer_obj)
                return -EINVAL;

        for (elem = 1, eloc = 1; elem < integer_obj_count; elem++, eloc++) {
                /* ONLY look at the first INTEGER_ELEM_CNT elements */
                if (eloc == INT_ELEM_CNT)
                        goto exit_integer_package;

                switch (integer_obj[elem].type) {
                case ACPI_TYPE_STRING:
                        if (elem != PREREQUISITES) {
                                ret = hp_convert_hexstr_to_str(integer_obj[elem].string.pointer,
                                                               integer_obj[elem].string.length,
                                                               &str_value, &value_len);
                                if (ret)
                                        continue;
                        }
                        break;
                case ACPI_TYPE_INTEGER:
                        int_value = (u32)integer_obj[elem].integer.value;
                        break;
                default:
                        pr_warn("Unsupported object type [%d]\n", integer_obj[elem].type);
                        continue;
                }
                /* Check that both expected and read object type match */
                if (expected_integer_types[eloc] != integer_obj[elem].type) {
                        pr_err("Error expected type %d for elem %d, but got type %d instead\n",
                               expected_integer_types[eloc], elem, integer_obj[elem].type);
                        kfree(str_value);
                        return -EIO;
                }
                /* Assign appropriate element value to corresponding field*/
                switch (eloc) {
                case VALUE:
                        ret = kstrtoint(str_value, 10, &int_value);
                        if (ret)
                                continue;

                        integer_data->current_value = int_value;
                        break;
                case PATH:
                        strscpy(integer_data->common.path, str_value);
                        break;
                case IS_READONLY:
                        integer_data->common.is_readonly = int_value;
                        break;
                case DISPLAY_IN_UI:
                        integer_data->common.display_in_ui = int_value;
                        break;
                case REQUIRES_PHYSICAL_PRESENCE:
                        integer_data->common.requires_physical_presence = int_value;
                        break;
                case SEQUENCE:
                        integer_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;
                        }
                        integer_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 (integer_data->common.prerequisites_size == 0)
                                eloc++;
                        break;
                case PREREQUISITES:
                        size = min_t(u32, integer_data->common.prerequisites_size, MAX_PREREQUISITES_SIZE);

                        for (reqs = 0; reqs < size; reqs++) {
                                if (elem + reqs >= integer_obj_count) {
                                        pr_err("Error elem-objects package is too small\n");
                                        return -EINVAL;
                                }

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

                                if (ret)
                                        continue;

                                strscpy(integer_data->common.prerequisites[reqs], str_value);
                                kfree(str_value);
                                str_value = NULL;
                        }
                        break;

                case SECURITY_LEVEL:
                        integer_data->common.security_level = int_value;
                        break;
                case INT_LOWER_BOUND:
                        integer_data->lower_bound = int_value;
                        break;
                case INT_UPPER_BOUND:
                        integer_data->upper_bound = int_value;
                        break;
                case INT_SCALAR_INCREMENT:
                        integer_data->scalar_increment = int_value;
                        break;
                default:
                        pr_warn("Invalid element: %d found in Integer attribute or data may be malformed\n", elem);
                        break;
                }

                kfree(str_value);
                str_value = NULL;
        }
exit_integer_package:
        kfree(str_value);
        return 0;
}

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

        integer_data->attr_name_kobj = attr_name_kobj;
        hp_populate_integer_elements_from_package(integer_obj,
                                                  integer_obj->package.count,
                                                  instance_id);
        hp_update_attribute_permissions(integer_data->common.is_readonly,
                                        &integer_current_val);
        hp_friendly_user_name_update(integer_data->common.path,
                                     attr_name_kobj->name,
                                     integer_data->common.display_name,
                                     sizeof(integer_data->common.display_name));
        return sysfs_create_group(attr_name_kobj, &integer_attr_group);
}

static int hp_populate_integer_elements_from_buffer(u8 *buffer_ptr, u32 *buffer_size,
                                                    int instance_id)
{
        char *dst = NULL;
        int dst_size = *buffer_size / sizeof(u16);
        struct integer_data *integer_data = &bioscfg_drv.integer_data[instance_id];
        int ret = 0;

        dst = kcalloc(dst_size, sizeof(char), GFP_KERNEL);
        if (!dst)
                return -ENOMEM;

        /*
         * 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:
        integer_data->current_value = 0;

        hp_get_string_from_buffer(&buffer_ptr, buffer_size, dst, dst_size);
        ret = kstrtoint(dst, 10, &integer_data->current_value);
        if (ret)
                pr_warn("Unable to convert string to integer: %s\n", dst);
        kfree(dst);

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

        // INT_LOWER_BOUND:
        ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
                                         &integer_data->lower_bound);
        if (ret < 0)
                goto buffer_exit;

        // INT_UPPER_BOUND:
        ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
                                         &integer_data->upper_bound);
        if (ret < 0)
                goto buffer_exit;

        // INT_SCALAR_INCREMENT:
        ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
                                         &integer_data->scalar_increment);

buffer_exit:
        return ret;
}

/**
 * hp_populate_integer_buffer_data() -
 * Populate all properties of an instance under integer 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_integer_buffer_data(u8 *buffer_ptr, u32 *buffer_size, int instance_id,
                                    struct kobject *attr_name_kobj)
{
        struct integer_data *integer_data = &bioscfg_drv.integer_data[instance_id];
        int ret = 0;

        integer_data->attr_name_kobj = attr_name_kobj;

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

        hp_update_attribute_permissions(integer_data->common.is_readonly,
                                        &integer_current_val);
        hp_friendly_user_name_update(integer_data->common.path,
                                     attr_name_kobj->name,
                                     integer_data->common.display_name,
                                     sizeof(integer_data->common.display_name));

        return sysfs_create_group(attr_name_kobj, &integer_attr_group);
}

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

        for (instance_id = 0; instance_id < bioscfg_drv.integer_instances_count;
             instance_id++) {
                struct kobject *attr_name_kobj =
                        bioscfg_drv.integer_data[instance_id].attr_name_kobj;

                if (attr_name_kobj)
                        sysfs_remove_group(attr_name_kobj, &integer_attr_group);
        }
        bioscfg_drv.integer_instances_count = 0;

        kfree(bioscfg_drv.integer_data);
        bioscfg_drv.integer_data = NULL;
}