drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c

// 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);

	bioscfg_drv.enumeration_data = kcalloc(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 >= 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 >= 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;

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