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Date:   Fri, 26 May 2023 17:27:59 +0200
From:   Thomas =?utf-8?Q?Wei=C3=9Fschuh?= <thomas@t-8ch.de>
To:     Jorge Lopez <jorgealtxwork@gmail.com>
Cc:     hdegoede@redhat.com, platform-driver-x86@vger.kernel.org,
        linux-kernel@vger.kernel.org, ilpo.jarvinen@linux.intel.com
Subject: Re: [PATCH v15 03/13] hp-bioscfg: bioscfg
Message-ID: <f147240d-7da8-4fd7-9201-a11476b0b9e6@t-8ch.de>
References: <20230519201300.12964-1-jorge.lopez2@hp.com>
 <20230519201300.12964-4-jorge.lopez2@hp.com>
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In-Reply-To: <20230519201300.12964-4-jorge.lopez2@hp.com>
Precedence: bulk

On 2023-05-19 15:12:50-0500, Jorge Lopez wrote:

<snip>

> ---
>  drivers/platform/x86/hp/hp-bioscfg/bioscfg.c | 988 +++++++++++++++++++
>  1 file changed, 988 insertions(+)
>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/bioscfg.c
> 
> diff --git a/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c
> new file mode 100644
> index 000000000000..fe0be40c8dee
> --- /dev/null
> +++ b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c
> @@ -0,0 +1,988 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Common methods for use with hp-bioscfg driver
> + *
> + *  Copyright (c) 2022 HP Development Company, L.P.
> + */
> +
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#include <linux/fs.h>
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/wmi.h>
> +#include "bioscfg.h"
> +#include "../../firmware_attributes_class.h"
> +#include <linux/nls.h>
> +#include <linux/errno.h>
> +
> +MODULE_AUTHOR("Jorge Lopez <jorge.lopez2@hp.com>");
> +MODULE_DESCRIPTION("HP BIOS Configuration Driver");
> +MODULE_LICENSE("GPL");
> +
> +struct bioscfg_priv bioscfg_drv = {
> +	.mutex = __MUTEX_INITIALIZER(bioscfg_drv.mutex),
> +};
> +
> +static struct class *fw_attr_class;
> +
> +ssize_t display_name_language_code_show(struct kobject *kobj,
> +					struct kobj_attribute *attr,
> +					char *buf)
> +{
> +	return sysfs_emit(buf, "%s\n", bioscfg_drv.display_name_language_code);
> +}

You probably can also define the "struct attribute" for this callback
right here.
Then there don't have to be attribute definitions everywhere.

As the language code is always the same anyways this can just print the
constant. Also remove the variables and explicit setting from all the
attributes.

> +
> +int hp_get_integer_from_buffer(u8 **buffer, u32 *buffer_size, u32 *integer)
> +{
> +	int *ptr = PTR_ALIGN((int *)*buffer, 4);

4 -> sizeof(int)

> +
> +	/* Ensure there is enough space remaining to read the integer */
> +	if (*buffer_size < sizeof(int))
> +		return -EINVAL;
> +
> +	*integer = *(ptr++);
> +	*buffer = (u8 *)ptr;
> +	*buffer_size -= sizeof(int);
> +
> +	return 0;
> +}
> +
> +int hp_get_string_from_buffer(u8 **buffer, u32 *buffer_size, char *dst, u32 dst_size)
> +{
> +	u16 *src = (u16 *)*buffer;
> +	u16 src_size;
> +
> +	u16 size;
> +	int i;
> +	int conv_dst_size;
> +
> +	if (*buffer_size < sizeof(u16))
> +		return -EINVAL;
> +
> +	src_size = *(src++);
> +	/* size value in u16 chars */
> +	size = src_size / sizeof(u16);
> +
> +	/* Ensure there is enough space remaining to read and convert
> +	 * the string
> +	 */
> +	if (*buffer_size < src_size)
> +		return -EINVAL;
> +
> +	for (i = 0; i < size; i++)
> +		if (src[i] == '\\' ||
> +		    src[i] == '\r' ||
> +		    src[i] == '\n' ||
> +		    src[i] == '\t')
> +			size++;
> +
> +	/*
> +	 * Conversion is limited to destination string max number of
> +	 * bytes.
> +	 */
> +	conv_dst_size = size;
> +	if (size > dst_size)
> +		conv_dst_size = dst_size - 1;
> +
> +	/*
> +	 * convert from UTF-16 unicode to ASCII
> +	 */
> +	utf16s_to_utf8s(src, src_size, UTF16_HOST_ENDIAN, dst, conv_dst_size);
> +	dst[conv_dst_size] = 0;
> +
> +	for (i = 0; i < size && i < conv_dst_size; i++) {
> +		if (*src == '\\' ||
> +		    *src == '\r' ||
> +		    *src == '\n' ||
> +		    *src == '\t')
> +			dst[i++] = '\\';
> +
> +		if (*src == '\r')
> +			dst[i] = 'r';
> +		else if (*src == '\n')
> +			dst[i] = 'n';
> +		else if (*src == '\t')
> +			dst[i] = 't';
> +		else if (*src == '"')
> +			dst[i] = '\'';
> +		else
> +			dst[i] = *src;
> +		src++;
> +	}
> +
> +	*buffer = (u8 *)src;
> +	*buffer_size -= size * sizeof(u16);
> +
> +	return size;
> +}
> +
> +int hp_enforce_single_line_input(char *buf, size_t count)
> +{
> +	char *p;
> +
> +	p = memchr(buf, '\n', count);
> +
> +	if (p == buf + count - 1)
> +		*p = '\0'; /* strip trailing newline */
> +	else if (p)
> +		return -EINVAL;  /* enforce single line input */
> +
> +	return 0;
> +}
> +
> +/* Set pending reboot value and generate KOBJ_NAME event */
> +void hp_set_reboot_and_signal_event(void)
> +{
> +	bioscfg_drv.pending_reboot = true;
> +	kobject_uevent(&bioscfg_drv.class_dev->kobj, KOBJ_CHANGE);
> +}
> +
> +/**
> + * hp_calculate_string_buffer() - determines size of string buffer for
> + * use with BIOS communication
> + *
> + * @str: the string to calculate based upon
> + */
> +size_t hp_calculate_string_buffer(const char *str)
> +{
> +	size_t length = strlen(str);
> +
> +	/* BIOS expects 4 bytes when an empty string is found */
> +	if (length == 0)
> +		return 4;
> +
> +	/* u16 length field + one UTF16 char for each input char */
> +	return sizeof(u16) + strlen(str) * sizeof(u16);
> +}
> +
> +int hp_wmi_error_and_message(int error_code)
> +{
> +	char *error_msg = NULL;
> +	int ret;
> +
> +	switch (error_code) {
> +	case SUCCESS:
> +		error_msg = "Success";
> +		ret = 0;
> +		break;
> +	case CMD_FAILED:
> +		error_msg = "Command failed";
> +		ret = -EINVAL;
> +		break;
> +	case INVALID_SIGN:
> +		error_msg = "Invalid signature";
> +		ret = -EINVAL;
> +		break;
> +	case INVALID_CMD_VALUE:
> +		error_msg = "Invalid command value/Feature not supported";
> +		ret = -EOPNOTSUPP;
> +		break;
> +	case INVALID_CMD_TYPE:
> +		error_msg = "Invalid command type";
> +		ret = -EINVAL;
> +		break;
> +	case INVALID_DATA_SIZE:
> +		error_msg = "Invalid data size";
> +		ret = -EINVAL;
> +		break;
> +	case INVALID_CMD_PARAM:
> +		error_msg = "Invalid command parameter";
> +		ret = -EINVAL;
> +		break;
> +	case ENCRYP_CMD_REQUIRED:
> +		error_msg = "Secure/encrypted command required";
> +		ret = -EACCES;
> +		break;
> +	case NO_SECURE_SESSION:
> +		error_msg = "No secure session established";
> +		ret = -EACCES;
> +		break;
> +	case SECURE_SESSION_FOUND:
> +		error_msg = "Secure session already established";
> +		ret = -EACCES;
> +		break;
> +	case SECURE_SESSION_FAILED:
> +		error_msg = "Secure session failed";
> +		ret = -EIO;
> +		break;
> +	case AUTH_FAILED:
> +		error_msg = "Other permission/Authentication failed";
> +		ret = -EACCES;
> +		break;
> +	case INVALID_BIOS_AUTH:
> +		error_msg = "Invalid BIOS administrator password";
> +		ret = -EINVAL;
> +		break;
> +	case NONCE_DID_NOT_MATCH:
> +		error_msg = "Nonce did not match";
> +		ret = -EINVAL;
> +		break;
> +	case GENERIC_ERROR:
> +		error_msg = "Generic/Other error";
> +		ret = -EIO;
> +		break;
> +	case BIOS_ADMIN_POLICY_NOT_MET:
> +		error_msg = "BIOS Admin password does not meet password policy requirements";
> +		ret = -EINVAL;
> +		break;
> +	case BIOS_ADMIN_NOT_SET:
> +		error_msg = "BIOS Setup password is not set";
> +		ret = -EPERM;
> +		break;
> +	case P21_NO_PROVISIONED:
> +		error_msg = "P21 is not provisioned";
> +		ret = -EPERM;
> +		break;
> +	case P21_PROVISION_IN_PROGRESS:
> +		error_msg = "P21 is already provisioned or provisioning is in progress and a signing key has already been sent";
> +		ret = -EINPROGRESS;
> +		break;
> +	case P21_IN_USE:
> +		error_msg = "P21 in use (cannot deprovision)";
> +		ret = -EPERM;
> +		break;
> +	case HEP_NOT_ACTIVE:
> +		error_msg = "HEP not activated";
> +		ret = -EPERM;
> +		break;
> +	case HEP_ALREADY_SET:
> +		error_msg = "HEP Transport already set";
> +		ret = -EINVAL;
> +		break;
> +	case HEP_CHECK_STATE:
> +		error_msg = "Check the current HEP state";
> +		ret = -EINVAL;
> +		break;
> +	default:
> +		error_msg = "Generic/Other error";
> +		ret = -EIO;
> +		break;
> +	}
> +
> +	if (error_code)
> +		pr_warn_ratelimited("Returned error 0x%x, \"%s\"\n", error_code, error_msg);
> +
> +	return ret;
> +}
> +
> +static ssize_t pending_reboot_show(struct kobject *kobj,
> +				   struct kobj_attribute *attr,
> +				   char *buf)
> +{
> +	return sysfs_emit(buf, "%d\n", bioscfg_drv.pending_reboot);
> +}
> +
> +static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot);
> +
> +/*
> + * create_attributes_level_sysfs_files() - Creates pending_reboot attributes
> + */
> +static int create_attributes_level_sysfs_files(void)
> +{
> +	return  sysfs_create_file(&bioscfg_drv.main_dir_kset->kobj,
> +				&pending_reboot.attr);
> +}
> +
> +static void attr_name_release(struct kobject *kobj)
> +{
> +	kfree(kobj);
> +}
> +
> +static const struct kobj_type attr_name_ktype = {
> +	.release	= attr_name_release,
> +	.sysfs_ops	= &kobj_sysfs_ops,
> +};
> +
> +/**
> + * hp_get_wmiobj_pointer() - Get Content of WMI block for particular instance
> + *
> + * @instance_id: WMI instance ID
> + * @guid_string: WMI GUID (in str form)
> + *
> + * Fetches the content for WMI block (instance_id) under GUID (guid_string)
> + * Caller must kfree the return
> + */
> +union acpi_object *hp_get_wmiobj_pointer(int instance_id, const char *guid_string)
> +{
> +	struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
> +	acpi_status status;
> +
> +	status = wmi_query_block(guid_string, instance_id, &out);
> +	return ACPI_SUCCESS(status) ? (union acpi_object *)out.pointer : NULL;
> +}
> +
> +/**
> + * hp_get_instance_count() - Compute total number of instances under guid_string
> + *
> + * @guid_string: WMI GUID (in string form)
> + */
> +int hp_get_instance_count(const char *guid_string)
> +{
> +	union acpi_object *wmi_obj = NULL;
> +	int i = 0;
> +
> +	do {
> +		kfree(wmi_obj);
> +		wmi_obj = hp_get_wmiobj_pointer(i, guid_string);
> +		i++;
> +	} while (wmi_obj);
> +
> +	return i - 1;
> +}
> +
> +/**
> + * hp_alloc_attributes_data() - Allocate attributes data for a particular type
> + *
> + * @attr_type: Attribute type to allocate
> + */
> +static int hp_alloc_attributes_data(int attr_type)
> +{
> +	switch (attr_type) {
> +	case HPWMI_STRING_TYPE:
> +		return hp_alloc_string_data();
> +
> +	case HPWMI_INTEGER_TYPE:
> +		return hp_alloc_integer_data();
> +
> +	case HPWMI_ENUMERATION_TYPE:
> +		return hp_alloc_enumeration_data();
> +
> +	case HPWMI_ORDERED_LIST_TYPE:
> +		return hp_alloc_ordered_list_data();
> +
> +	case HPWMI_PASSWORD_TYPE:
> +		return hp_alloc_password_data();
> +
> +	default:
> +		return 0;
> +	}
> +}
> +
> +int hp_convert_hexstr_to_str(const char *input, u32 input_len, char **str, int *len)
> +{
> +	int ret = 0;
> +	int new_len = 0;
> +	char tmp[] = "0x00";
> +	char *new_str = NULL;
> +	long  ch;
> +	int i;
> +
> +	if (input_len <= 0 || !input || !str || !len)
> +		return -EINVAL;
> +
> +	*len = 0;
> +	*str = NULL;
> +
> +	new_str = kmalloc(input_len, GFP_KERNEL);
> +	if (!new_str)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < input_len; i += 5) {
> +		strncpy(tmp, input + i, strlen(tmp));
> +		if (kstrtol(tmp, 16, &ch) == 0) {
> +			// escape char
> +			if (ch == '\\' ||
> +			    ch == '\r' ||
> +			    ch == '\n' || ch == '\t') {
> +				if (ch == '\r')
> +					ch = 'r';
> +				else if (ch == '\n')
> +					ch = 'n';
> +				else if (ch == '\t')
> +					ch = 't';
> +				new_str[new_len++] = '\\';
> +			}
> +			new_str[new_len++] = ch;
> +			if (ch == '\0')
> +				break;
> +		}
> +	}
> +
> +	if (new_len) {
> +		new_str[new_len] = '\0';
> +		*str = krealloc(new_str, (new_len + 1) * sizeof(char),
> +				GFP_KERNEL);
> +		if (*str)
> +			*len = new_len;
> +		else
> +			ret = -ENOMEM;
> +	} else {
> +		ret = -EFAULT;
> +	}
> +
> +	if (ret)
> +		kfree(new_str);
> +	return ret;
> +}
> +
> +/* map output size to the corresponding WMI method id */
> +int hp_encode_outsize_for_pvsz(int outsize)
> +{
> +	if (outsize > 4096)
> +		return -EINVAL;
> +	if (outsize > 1024)
> +		return 5;
> +	if (outsize > 128)
> +		return 4;
> +	if (outsize > 4)
> +		return 3;
> +	if (outsize > 0)
> +		return 2;
> +	return 1;
> +}
> +
> +/*
> + * Update friendly display name for several attributes associated to
> + * 'Schedule Power-On'
> + */
> +void hp_friendly_user_name_update(char *path, const char *attr_name,
> +				  char *attr_display, int attr_size)
> +{
> +	if (strstr(path, SCHEDULE_POWER_ON))
> +		snprintf(attr_display, attr_size, "%s - %s", SCHEDULE_POWER_ON, attr_name);
> +	else
> +		strscpy(attr_display, attr_name, attr_size);
> +}
> +
> +/**
> + * hp_update_attribute_permissions() - Update attributes permissions when
> + * isReadOnly value is 1
> + *
> + * @is_readonly:  bool value to indicate if it a readonly attribute.
> + * @current_val: kobj_attribute corresponding to attribute.
> + *
> + */
> +void hp_update_attribute_permissions(bool is_readonly, struct kobj_attribute *current_val)
> +{
> +	current_val->attr.mode = is_readonly ? 0444 : 0644;
> +}
> +
> +/**
> + * destroy_attribute_objs() - Free a kset of kobjects
> + * @kset: The kset to destroy
> + *
> + * Fress kobjects created for each attribute_name under attribute type kset
> + */
> +static void destroy_attribute_objs(struct kset *kset)
> +{
> +	struct kobject *pos, *next;
> +
> +	list_for_each_entry_safe(pos, next, &kset->list, entry)
> +		kobject_put(pos);
> +}
> +
> +/**
> + * release_attributes_data() - Clean-up all sysfs directories and files created
> + */
> +static void release_attributes_data(void)
> +{
> +	mutex_lock(&bioscfg_drv.mutex);
> +
> +	hp_exit_string_attributes();
> +	hp_exit_integer_attributes();
> +	hp_exit_enumeration_attributes();
> +	hp_exit_ordered_list_attributes();
> +	hp_exit_password_attributes();
> +	hp_exit_sure_start_attributes();
> +	hp_exit_secure_platform_attributes();
> +
> +	if (bioscfg_drv.authentication_dir_kset) {
> +		destroy_attribute_objs(bioscfg_drv.authentication_dir_kset);
> +		kset_unregister(bioscfg_drv.authentication_dir_kset);
> +		bioscfg_drv.authentication_dir_kset = NULL;
> +	}
> +	if (bioscfg_drv.main_dir_kset) {
> +		sysfs_remove_file(&bioscfg_drv.main_dir_kset->kobj, &pending_reboot.attr);
> +		destroy_attribute_objs(bioscfg_drv.main_dir_kset);
> +		kset_unregister(bioscfg_drv.main_dir_kset);
> +		bioscfg_drv.main_dir_kset = NULL;
> +	}
> +	mutex_unlock(&bioscfg_drv.mutex);
> +}
> +
> +/**
> + * hp_add_other_attributes() - Initialize HP custom attributes not
> + * reported by BIOS and required to support Secure Platform and Sure
> + * Start.
> + *
> + * @attr_type: Custom HP attribute not reported by BIOS
> + *
> + * Initialize all 2 types of attributes: Platform and Sure Start
> + * object.  Populates each attribute types respective properties
> + * under sysfs files.
> + *
> + * Returns zero(0) if successful. Otherwise, a negative value.
> + */
> +static int hp_add_other_attributes(int attr_type)
> +{
> +	struct kobject *attr_name_kobj;
> +	union acpi_object *obj = NULL;
> +	int retval;
> +	char *attr_name;
> +
> +	mutex_lock(&bioscfg_drv.mutex);
> +
> +	attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL);
> +	if (!attr_name_kobj) {
> +		retval = -ENOMEM;
> +		goto err_other_attr_init;
> +	}
> +
> +	/* Check if attribute type is supported */
> +	switch (attr_type) {
> +	case HPWMI_SECURE_PLATFORM_TYPE:
> +		attr_name_kobj->kset = bioscfg_drv.authentication_dir_kset;
> +		attr_name = SPM_STR;
> +		break;
> +
> +	case HPWMI_SURE_START_TYPE:
> +		attr_name_kobj->kset = bioscfg_drv.main_dir_kset;
> +		attr_name = SURE_START_STR;
> +		break;
> +
> +	default:
> +		pr_err("Error: Unknown attr_type: %d\n", attr_type);
> +		retval = -EINVAL;
> +		goto err_other_attr_init;
> +	}
> +
> +	retval = kobject_init_and_add(attr_name_kobj, &attr_name_ktype,
> +				      NULL, "%s", attr_name);
> +	if (retval) {
> +		pr_err("Error encountered [%d]\n", retval);
> +		kobject_put(attr_name_kobj);
> +		goto err_other_attr_init;
> +	}
> +
> +	/* Populate attribute data */
> +	switch (attr_type) {
> +	case HPWMI_SECURE_PLATFORM_TYPE:
> +		retval = hp_populate_secure_platform_data(attr_name_kobj);
> +		break;
> +
> +	case HPWMI_SURE_START_TYPE:
> +		retval = hp_populate_sure_start_data(attr_name_kobj);
> +		break;
> +
> +	default:
> +		goto err_other_attr_init;
> +	}
> +
> +	mutex_unlock(&bioscfg_drv.mutex);
> +	return 0;
> +
> +err_other_attr_init:
> +	mutex_unlock(&bioscfg_drv.mutex);
> +	kfree(obj);
> +	return retval;
> +}
> +
> +static int hp_init_bios_package_attribute(enum hp_wmi_data_type attr_type,
> +					  union acpi_object *obj,
> +					  const char *guid, int min_elements,
> +					  int instance_id)
> +{
> +	struct kobject *attr_name_kobj;
> +	union acpi_object *elements;
> +	struct kset *temp_kset;
> +
> +	char *str_value = NULL;
> +	int str_len;
> +	int retval = 0;
> +
> +	/* Take action appropriate to each ACPI TYPE */
> +	if (obj->package.count < min_elements) {
> +		pr_err("ACPI-package does not have enough elements: %d < %d\n",
> +		       obj->package.count, min_elements);
> +		goto pack_attr_exit;
> +	}
> +
> +	elements = obj->package.elements;
> +
> +	/* sanity checking */
> +	if (elements[NAME].type != ACPI_TYPE_STRING) {
> +		pr_debug("incorrect element type\n");
> +		goto pack_attr_exit;
> +	}
> +	if (strlen(elements[NAME].string.pointer) == 0) {
> +		pr_debug("empty attribute found\n");
> +		goto pack_attr_exit;
> +	}
> +
> +	if (attr_type == HPWMI_PASSWORD_TYPE)
> +		temp_kset = bioscfg_drv.authentication_dir_kset;
> +	else
> +		temp_kset = bioscfg_drv.main_dir_kset;
> +
> +	/* convert attribute name to string */
> +	retval = hp_convert_hexstr_to_str(elements[NAME].string.pointer,
> +					  elements[NAME].string.length,
> +					  &str_value, &str_len);
> +
> +	if (retval) {
> +		pr_debug("Failed to populate integer package data. Error [0%0x]\n",
> +			 retval);
> +		kfree(str_value);
> +		return retval;
> +	}
> +
> +	/* All duplicate attributes found are ignored */
> +	if (kset_find_obj(temp_kset, str_value)) {
> +		pr_debug("Duplicate attribute name found - %s\n",
> +			 str_value);
> +		goto pack_attr_exit;
> +	}
> +
> +	/* build attribute */
> +	attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL);
> +	if (!attr_name_kobj) {
> +		retval = -ENOMEM;
> +		goto pack_attr_exit;
> +	}
> +
> +	attr_name_kobj->kset = temp_kset;
> +
> +	retval = kobject_init_and_add(attr_name_kobj, &attr_name_ktype,
> +				      NULL, "%s", str_value);
> +
> +	if (retval) {
> +		kobject_put(attr_name_kobj);
> +		goto pack_attr_exit;
> +	}
> +
> +	/* enumerate all of these attributes */
> +	switch (attr_type) {
> +	case HPWMI_STRING_TYPE:
> +		retval = hp_populate_string_package_data(elements,
> +							 instance_id,
> +							 attr_name_kobj);
> +		break;
> +	case HPWMI_INTEGER_TYPE:
> +		retval = hp_populate_integer_package_data(elements,
> +							  instance_id,
> +							  attr_name_kobj);
> +		break;
> +	case HPWMI_ENUMERATION_TYPE:
> +		retval = hp_populate_enumeration_package_data(elements,
> +							      instance_id,
> +							      attr_name_kobj);
> +		break;
> +	case HPWMI_ORDERED_LIST_TYPE:
> +		retval = hp_populate_ordered_list_package_data(elements,
> +							       instance_id,
> +							       attr_name_kobj);
> +		break;
> +	case HPWMI_PASSWORD_TYPE:
> +		retval = hp_populate_password_package_data(elements,
> +							   instance_id,
> +							   attr_name_kobj);
> +		break;
> +	default:
> +		pr_debug("Unknown attribute type found: 0x%x\n", attr_type);
> +		break;
> +	}
> +
> +pack_attr_exit:
> +	kfree(str_value);
> +	return retval;
> +}
> +
> +static int hp_init_bios_buffer_attribute(enum hp_wmi_data_type attr_type,
> +					 union acpi_object *obj,
> +					 const char *guid, int min_elements,
> +					 int instance_id)
> +{
> +	struct kobject *attr_name_kobj;
> +	struct kset *temp_kset;
> +	char str[MAX_BUFF_SIZE];
> +
> +	char *temp_str = NULL;
> +	char *str_value = NULL;
> +	u8 *buffer_ptr = NULL;
> +	int buffer_size;
> +	int retval = 0;
> +
> +	buffer_size = obj->buffer.length;
> +	buffer_ptr = obj->buffer.pointer;
> +
> +	retval = hp_get_string_from_buffer(&buffer_ptr,
> +					   &buffer_size, str, MAX_BUFF_SIZE);
> +
> +	if (retval < 0)
> +		goto buff_attr_exit;
> +
> +	if (attr_type == HPWMI_PASSWORD_TYPE ||
> +	    attr_type == HPWMI_SECURE_PLATFORM_TYPE)
> +		temp_kset = bioscfg_drv.authentication_dir_kset;
> +	else
> +		temp_kset = bioscfg_drv.main_dir_kset;
> +
> +	/* All duplicate attributes found are ignored */
> +	if (kset_find_obj(temp_kset, str)) {
> +		pr_debug("Duplicate attribute name found - %s\n", str);
> +		goto buff_attr_exit;
> +	}
> +
> +	/* build attribute */
> +	attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL);
> +	if (!attr_name_kobj) {
> +		retval = -ENOMEM;
> +		goto buff_attr_exit;
> +	}
> +
> +	attr_name_kobj->kset = temp_kset;
> +
> +	temp_str = str;
> +	if (attr_type == HPWMI_SECURE_PLATFORM_TYPE)
> +		temp_str = "SPM";
> +
> +	retval = kobject_init_and_add(attr_name_kobj,
> +				      &attr_name_ktype, NULL, "%s",
> +				      temp_str);
> +	if (retval) {
> +		kobject_put(attr_name_kobj);
> +		goto buff_attr_exit;
> +	}
> +
> +	/* enumerate all of these attributes */
> +	switch (attr_type) {
> +	case HPWMI_STRING_TYPE:
> +		retval = hp_populate_string_buffer_data(buffer_ptr,
> +							&buffer_size,
> +							instance_id,
> +							attr_name_kobj);
> +		break;
> +	case HPWMI_INTEGER_TYPE:
> +		retval = hp_populate_integer_buffer_data(buffer_ptr,
> +							 &buffer_size,
> +							 instance_id,
> +							 attr_name_kobj);
> +		break;
> +	case HPWMI_ENUMERATION_TYPE:
> +		retval = hp_populate_enumeration_buffer_data(buffer_ptr,
> +							     &buffer_size,
> +							     instance_id,
> +							     attr_name_kobj);
> +		break;
> +	case HPWMI_ORDERED_LIST_TYPE:
> +		retval = hp_populate_ordered_list_buffer_data(buffer_ptr,
> +							      &buffer_size,
> +							      instance_id,
> +							      attr_name_kobj);
> +		break;
> +	case HPWMI_PASSWORD_TYPE:
> +		retval = hp_populate_password_buffer_data(buffer_ptr,
> +							  &buffer_size,
> +							  instance_id,
> +							  attr_name_kobj);
> +		break;
> +	default:
> +		pr_debug("Unknown attribute type found: 0x%x\n", attr_type);
> +		break;
> +	}
> +
> +buff_attr_exit:
> +	kfree(str_value);
> +	return retval;
> +}
> +
> +/**
> + * hp_init_bios_attributes() - Initialize all attributes for a type
> + * @attr_type: The attribute type to initialize
> + * @guid: The WMI GUID associated with this type to initialize
> + *
> + * Initialiaze all 5 types of attributes: enumeration, integer,

"Initialize"

> + * string, password, ordered list  object.  Populates each attrbute types
> + * respective properties under sysfs files
> + */
> +static int hp_init_bios_attributes(enum hp_wmi_data_type attr_type, const char *guid)
> +{
> +	union acpi_object *obj = NULL;
> +	int min_elements;
> +
> +	/* instance_id needs to be reset for each type GUID
> +	 * also, instance IDs are unique within GUID but not across
> +	 */
> +	int instance_id = 0;
> +	int retval = 0;

More common would be just "ret" instead of "retval".
Same everywhere else.

> +
> +	retval = hp_alloc_attributes_data(attr_type);
> +	if (retval)
> +		return retval;
> +
> +	switch (attr_type) {
> +	case HPWMI_STRING_TYPE:
> +		min_elements = STR_ELEM_CNT;
> +		break;
> +	case HPWMI_INTEGER_TYPE:
> +		min_elements = INT_ELEM_CNT;
> +		break;
> +	case HPWMI_ENUMERATION_TYPE:
> +		min_elements = ENUM_ELEM_CNT;
> +		break;
> +	case HPWMI_ORDERED_LIST_TYPE:
> +		min_elements = ORD_ELEM_CNT;
> +		break;
> +	case HPWMI_PASSWORD_TYPE:
> +		min_elements = PSWD_ELEM_CNT;
> +		break;
> +	default:
> +		pr_err("Error: Unknown attr_type: %d\n", attr_type);
> +		return -EINVAL;
> +	}
> +
> +	/* Report display name language code */
> +	strscpy(bioscfg_drv.display_name_language_code,
> +		LANG_CODE_STR,
> +		sizeof(bioscfg_drv.display_name_language_code));
> +
> +	/* need to use specific instance_id and guid combination to get right data */
> +	obj = hp_get_wmiobj_pointer(instance_id, guid);
> +	if (!obj)
> +		return -ENODEV;
> +
> +	mutex_lock(&bioscfg_drv.mutex);
> +	while (obj) {
> +		/* Take action appropriate to each ACPI TYPE */
> +		if (obj->type == ACPI_TYPE_PACKAGE) {
> +			retval = hp_init_bios_package_attribute(attr_type, obj,
> +								guid, min_elements,
> +								instance_id);
> +			if (retval)
> +				goto err_attr_init;
> +		} else if (obj->type == ACPI_TYPE_BUFFER) {
> +			retval = hp_init_bios_buffer_attribute(attr_type, obj,
> +							       guid, min_elements,
> +							       instance_id);
> +			if (retval)
> +				goto err_attr_init;
> +		} else {
> +			pr_err("Expected ACPI-package or buffer type, got: %d\n",
> +			       obj->type);
> +			retval = -EIO;
> +			goto err_attr_init;
> +		}
> +
> +		kfree(obj);
> +		instance_id++;
> +		obj = hp_get_wmiobj_pointer(instance_id, guid);
> +	}
> +
> +err_attr_init:
> +	mutex_unlock(&bioscfg_drv.mutex);
> +	kfree(obj);
> +	return retval;
> +}
> +
> +static int __init hp_init(void)
> +{
> +	int ret;
> +	int hp_bios_capable = wmi_has_guid(HP_WMI_BIOS_GUID);
> +	int set_bios_settings = wmi_has_guid(HP_WMI_SET_BIOS_SETTING_GUID);
> +
> +	if (!hp_bios_capable) {
> +		pr_err("Unable to run on non-HP system\n");
> +		return -ENODEV;
> +	}
> +
> +	if (!set_bios_settings) {
> +		pr_err("Unable to set BIOS settings on HP systems\n");
> +		return -ENODEV;
> +	}
> +
> +	ret = hp_init_attr_set_interface();
> +	if (ret)
> +		return ret;
> +
> +	ret = fw_attributes_class_get(&fw_attr_class);
> +	if (ret)
> +		goto err_unregister_class;
> +
> +	bioscfg_drv.class_dev = device_create(fw_attr_class, NULL, MKDEV(0, 0),
> +					      NULL, "%s", DRIVER_NAME);
> +	if (IS_ERR(bioscfg_drv.class_dev)) {
> +		ret = PTR_ERR(bioscfg_drv.class_dev);
> +		goto err_unregister_class;
> +	}
> +
> +	bioscfg_drv.main_dir_kset = kset_create_and_add("attributes", NULL,
> +							&bioscfg_drv.class_dev->kobj);
> +	if (!bioscfg_drv.main_dir_kset) {
> +		ret = -ENOMEM;
> +		pr_debug("Failed to create and add attributes\n");
> +		goto err_destroy_classdev;
> +	}
> +
> +	bioscfg_drv.authentication_dir_kset = kset_create_and_add("authentication", NULL,
> +								  &bioscfg_drv.class_dev->kobj);
> +	if (!bioscfg_drv.authentication_dir_kset) {
> +		ret = -ENOMEM;
> +		pr_debug("Failed to create and add authentication\n");
> +		goto err_release_attributes_data;
> +	}
> +
> +	/*
> +	 * sysfs level attributes.
> +	 * - pending_reboot
> +	 */
> +	ret = create_attributes_level_sysfs_files();
> +	if (ret)
> +		pr_debug("Failed to create sysfs level attributes\n");
> +
> +	ret = hp_init_bios_attributes(HPWMI_STRING_TYPE, HP_WMI_BIOS_STRING_GUID);
> +	if (ret)
> +		pr_debug("Failed to populate string type attributes\n");
> +
> +	ret = hp_init_bios_attributes(HPWMI_INTEGER_TYPE, HP_WMI_BIOS_INTEGER_GUID);
> +	if (ret)
> +		pr_debug("Failed to populate integer type attributes\n");
> +
> +	ret = hp_init_bios_attributes(HPWMI_ENUMERATION_TYPE, HP_WMI_BIOS_ENUMERATION_GUID);
> +	if (ret)
> +		pr_debug("Failed to populate enumeration type attributes\n");
> +
> +	ret = hp_init_bios_attributes(HPWMI_ORDERED_LIST_TYPE, HP_WMI_BIOS_ORDERED_LIST_GUID);
> +	if (ret)
> +		pr_debug("Failed to populate ordered list object type attributes\n");
> +
> +	ret = hp_init_bios_attributes(HPWMI_PASSWORD_TYPE, HP_WMI_BIOS_PASSWORD_GUID);
> +	if (ret)
> +		pr_debug("Failed to populate password object type attributes\n");
> +
> +	bioscfg_drv.spm_data.attr_name_kobj = NULL;
> +	ret = hp_add_other_attributes(HPWMI_SECURE_PLATFORM_TYPE);
> +	if (ret)
> +		pr_debug("Failed to populate secure platform object type attribute\n");
> +
> +	bioscfg_drv.sure_start_attr_kobj = NULL;
> +	ret = hp_add_other_attributes(HPWMI_SURE_START_TYPE);
> +	if (ret)
> +		pr_debug("Failed to populate sure start object type attribute\n");
> +
> +	return 0;
> +
> +err_release_attributes_data:
> +	release_attributes_data();
> +
> +err_destroy_classdev:
> +	device_destroy(fw_attr_class, MKDEV(0, 0));
> +
> +err_unregister_class:
> +	fw_attributes_class_put();
> +	hp_exit_attr_set_interface();
> +
> +	return ret;
> +}
> +
> +static void __exit hp_exit(void)
> +{
> +	release_attributes_data();
> +	device_destroy(fw_attr_class, MKDEV(0, 0));
> +
> +	fw_attributes_class_put();
> +	hp_exit_attr_set_interface();
> +}
> +
> +module_init(hp_init);
> +module_exit(hp_exit);
> -- 
> 2.34.1
>