1 // SPDX-License-Identifier: GPL-2.0
3 * Common methods for use with dell-wmi-sysman
5 * Copyright (c) 2020 Dell Inc.
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11 #include <linux/dmi.h>
12 #include <linux/module.h>
13 #include <linux/kernel.h>
14 #include <linux/wmi.h>
15 #include "dell-wmi-sysman.h"
18 #include <linux/nls.h>
20 static struct class firmware_attributes_class = {
21 .name = "firmware-attributes",
24 struct wmi_sysman_priv wmi_priv = {
25 .mutex = __MUTEX_INITIALIZER(wmi_priv.mutex),
28 /* reset bios to defaults */
29 static const char * const reset_types[] = {"builtinsafe", "lastknowngood", "factory", "custom"};
30 static int reset_option = -1;
34 * populate_string_buffer() - populates a string buffer
35 * @buffer: the start of the destination buffer
36 * @buffer_len: length of the destination buffer
37 * @str: the string to insert into buffer
39 ssize_t populate_string_buffer(char *buffer, size_t buffer_len, const char *str)
41 u16 *length = (u16 *)buffer;
42 u16 *target = length + 1;
45 ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN,
46 target, buffer_len - sizeof(u16));
48 dev_err(wmi_priv.class_dev, "UTF16 conversion failed\n");
52 if ((ret * sizeof(u16)) > U16_MAX) {
53 dev_err(wmi_priv.class_dev, "Error string too long\n");
57 *length = ret * sizeof(u16);
58 return sizeof(u16) + *length;
62 * calculate_string_buffer() - determines size of string buffer for use with BIOS communication
63 * @str: the string to calculate based upon
66 size_t calculate_string_buffer(const char *str)
68 /* u16 length field + one UTF16 char for each input char */
69 return sizeof(u16) + strlen(str) * sizeof(u16);
73 * calculate_security_buffer() - determines size of security buffer for authentication scheme
74 * @authentication: the authentication content
76 * Currently only supported type is Admin password
78 size_t calculate_security_buffer(char *authentication)
80 if (strlen(authentication) > 0) {
81 return (sizeof(u32) * 2) + strlen(authentication) +
82 strlen(authentication) % 2;
84 return sizeof(u32) * 2;
88 * populate_security_buffer() - builds a security buffer for authentication scheme
89 * @buffer: the buffer to populate
90 * @authentication: the authentication content
92 * Currently only supported type is PLAIN TEXT
94 void populate_security_buffer(char *buffer, char *authentication)
96 char *auth = buffer + sizeof(u32) * 2;
97 u32 *sectype = (u32 *) buffer;
98 u32 *seclen = sectype + 1;
100 *sectype = strlen(authentication) > 0 ? 1 : 0;
101 *seclen = strlen(authentication);
104 if (strlen(authentication) > 0)
105 memcpy(auth, authentication, *seclen);
109 * map_wmi_error() - map errors from WMI methods to kernel error codes
110 * @error_code: integer error code returned from Dell's firmware
112 int map_wmi_error(int error_code)
114 switch (error_code) {
122 /* invalid parameter */
137 /* unspecified error */
142 * reset_bios_show() - sysfs implementaton for read reset_bios
143 * @kobj: Kernel object for this attribute
144 * @attr: Kernel object attribute
145 * @buf: The buffer to display to userspace
147 static ssize_t reset_bios_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
152 for (i = 0; i < MAX_TYPES; i++) {
153 if (i == reset_option)
154 buf += sprintf(buf, "[%s] ", reset_types[i]);
156 buf += sprintf(buf, "%s ", reset_types[i]);
158 buf += sprintf(buf, "\n");
163 * reset_bios_store() - sysfs implementaton for write reset_bios
164 * @kobj: Kernel object for this attribute
165 * @attr: Kernel object attribute
166 * @buf: The buffer from userspace
167 * @count: the size of the buffer from userspace
169 static ssize_t reset_bios_store(struct kobject *kobj,
170 struct kobj_attribute *attr, const char *buf, size_t count)
172 int type = sysfs_match_string(reset_types, buf);
178 ret = set_bios_defaults(type);
179 pr_debug("reset all attributes request type %d: %d\n", type, ret);
189 * pending_reboot_show() - sysfs implementaton for read pending_reboot
190 * @kobj: Kernel object for this attribute
191 * @attr: Kernel object attribute
192 * @buf: The buffer to display to userspace
194 * Stores default value as 0
195 * When current_value is changed this attribute is set to 1 to notify reboot may be required
197 static ssize_t pending_reboot_show(struct kobject *kobj, struct kobj_attribute *attr,
200 return sprintf(buf, "%d\n", wmi_priv.pending_changes);
203 static struct kobj_attribute reset_bios = __ATTR_RW(reset_bios);
204 static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot);
208 * create_attributes_level_sysfs_files() - Creates reset_bios and
209 * pending_reboot attributes
211 static int create_attributes_level_sysfs_files(void)
213 int ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
216 pr_debug("could not create reset_bios file\n");
220 ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
222 pr_debug("could not create changing_pending_reboot file\n");
223 sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
228 static void release_reset_bios_data(void)
230 sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
231 sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
234 static ssize_t wmi_sysman_attr_show(struct kobject *kobj, struct attribute *attr,
237 struct kobj_attribute *kattr;
240 kattr = container_of(attr, struct kobj_attribute, attr);
242 ret = kattr->show(kobj, kattr, buf);
246 static ssize_t wmi_sysman_attr_store(struct kobject *kobj, struct attribute *attr,
247 const char *buf, size_t count)
249 struct kobj_attribute *kattr;
252 kattr = container_of(attr, struct kobj_attribute, attr);
254 ret = kattr->store(kobj, kattr, buf, count);
258 const struct sysfs_ops wmi_sysman_kobj_sysfs_ops = {
259 .show = wmi_sysman_attr_show,
260 .store = wmi_sysman_attr_store,
263 static void attr_name_release(struct kobject *kobj)
268 static struct kobj_type attr_name_ktype = {
269 .release = attr_name_release,
270 .sysfs_ops = &wmi_sysman_kobj_sysfs_ops,
274 * strlcpy_attr - Copy a length-limited, NULL-terminated string with bound checks
275 * @dest: Where to copy the string to
276 * @src: Where to copy the string from
278 void strlcpy_attr(char *dest, char *src)
280 size_t len = strlen(src) + 1;
282 if (len > 1 && len <= MAX_BUFF)
283 strlcpy(dest, src, len);
285 /*len can be zero because any property not-applicable to attribute can
286 * be empty so check only for too long buffers and log error
289 pr_err("Source string returned from BIOS is out of bound!\n");
293 * get_wmiobj_pointer() - Get Content of WMI block for particular instance
294 * @instance_id: WMI instance ID
295 * @guid_string: WMI GUID (in str form)
297 * Fetches the content for WMI block (instance_id) under GUID (guid_string)
298 * Caller must kfree the return
300 union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string)
302 struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
305 status = wmi_query_block(guid_string, instance_id, &out);
307 return ACPI_SUCCESS(status) ? (union acpi_object *)out.pointer : NULL;
311 * get_instance_count() - Compute total number of instances under guid_string
312 * @guid_string: WMI GUID (in string form)
314 int get_instance_count(const char *guid_string)
316 union acpi_object *wmi_obj = NULL;
321 wmi_obj = get_wmiobj_pointer(i, guid_string);
329 * alloc_attributes_data() - Allocate attributes data for a particular type
330 * @attr_type: Attribute type to allocate
332 static int alloc_attributes_data(int attr_type)
338 retval = alloc_enum_data();
341 retval = alloc_int_data();
344 retval = alloc_str_data();
347 retval = alloc_po_data();
357 * destroy_attribute_objs() - Free a kset of kobjects
358 * @kset: The kset to destroy
360 * Fress kobjects created for each attribute_name under attribute type kset
362 static void destroy_attribute_objs(struct kset *kset)
364 struct kobject *pos, *next;
366 list_for_each_entry_safe(pos, next, &kset->list, entry) {
372 * release_attributes_data() - Clean-up all sysfs directories and files created
374 static void release_attributes_data(void)
376 release_reset_bios_data();
378 mutex_lock(&wmi_priv.mutex);
379 exit_enum_attributes();
380 exit_int_attributes();
381 exit_str_attributes();
382 exit_po_attributes();
383 if (wmi_priv.authentication_dir_kset) {
384 destroy_attribute_objs(wmi_priv.authentication_dir_kset);
385 kset_unregister(wmi_priv.authentication_dir_kset);
386 wmi_priv.authentication_dir_kset = NULL;
388 if (wmi_priv.main_dir_kset) {
389 destroy_attribute_objs(wmi_priv.main_dir_kset);
390 kset_unregister(wmi_priv.main_dir_kset);
392 mutex_unlock(&wmi_priv.mutex);
397 * init_bios_attributes() - Initialize all attributes for a type
398 * @attr_type: The attribute type to initialize
399 * @guid: The WMI GUID associated with this type to initialize
401 * Initialiaze all 4 types of attributes enumeration, integer, string and password object.
402 * Populates each attrbute typ's respective properties under sysfs files
404 static int init_bios_attributes(int attr_type, const char *guid)
406 struct kobject *attr_name_kobj; //individual attribute names
407 union acpi_object *obj = NULL;
408 union acpi_object *elements;
409 struct kset *tmp_set;
411 /* instance_id needs to be reset for each type GUID
412 * also, instance IDs are unique within GUID but not across
417 retval = alloc_attributes_data(attr_type);
420 /* need to use specific instance_id and guid combination to get right data */
421 obj = get_wmiobj_pointer(instance_id, guid);
424 elements = obj->package.elements;
426 mutex_lock(&wmi_priv.mutex);
428 /* sanity checking */
429 if (strlen(elements[ATTR_NAME].string.pointer) == 0) {
430 pr_debug("empty attribute found\n");
434 tmp_set = wmi_priv.authentication_dir_kset;
436 tmp_set = wmi_priv.main_dir_kset;
438 if (kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer)) {
439 pr_debug("duplicate attribute name found - %s\n",
440 elements[ATTR_NAME].string.pointer);
444 /* build attribute */
445 attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL);
449 attr_name_kobj->kset = tmp_set;
451 retval = kobject_init_and_add(attr_name_kobj, &attr_name_ktype, NULL, "%s",
452 elements[ATTR_NAME].string.pointer);
454 kobject_put(attr_name_kobj);
458 /* enumerate all of this attribute */
461 retval = populate_enum_data(elements, instance_id, attr_name_kobj);
464 retval = populate_int_data(elements, instance_id, attr_name_kobj);
467 retval = populate_str_data(elements, instance_id, attr_name_kobj);
470 retval = populate_po_data(elements, instance_id, attr_name_kobj);
477 pr_debug("failed to populate %s\n",
478 elements[ATTR_NAME].string.pointer);
485 obj = get_wmiobj_pointer(instance_id, guid);
486 elements = obj ? obj->package.elements : NULL;
492 release_attributes_data();
495 mutex_unlock(&wmi_priv.mutex);
499 static int __init sysman_init(void)
503 if (!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL) &&
504 !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "www.dell.com", NULL)) {
505 pr_err("Unable to run on non-Dell system\n");
509 ret = init_bios_attr_set_interface();
510 if (ret || !wmi_priv.bios_attr_wdev) {
511 pr_debug("failed to initialize set interface\n");
512 goto fail_set_interface;
515 ret = init_bios_attr_pass_interface();
516 if (ret || !wmi_priv.password_attr_wdev) {
517 pr_debug("failed to initialize pass interface\n");
518 goto fail_pass_interface;
521 ret = class_register(&firmware_attributes_class);
525 wmi_priv.class_dev = device_create(&firmware_attributes_class, NULL, MKDEV(0, 0),
526 NULL, "%s", DRIVER_NAME);
527 if (IS_ERR(wmi_priv.class_dev)) {
528 ret = PTR_ERR(wmi_priv.class_dev);
532 wmi_priv.main_dir_kset = kset_create_and_add("attributes", NULL,
533 &wmi_priv.class_dev->kobj);
534 if (!wmi_priv.main_dir_kset) {
539 wmi_priv.authentication_dir_kset = kset_create_and_add("authentication", NULL,
540 &wmi_priv.class_dev->kobj);
541 if (!wmi_priv.authentication_dir_kset) {
543 goto fail_authentication_kset;
546 ret = create_attributes_level_sysfs_files();
548 pr_debug("could not create reset BIOS attribute\n");
549 goto fail_reset_bios;
552 ret = init_bios_attributes(ENUM, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
554 pr_debug("failed to populate enumeration type attributes\n");
555 goto fail_create_group;
558 ret = init_bios_attributes(INT, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
560 pr_debug("failed to populate integer type attributes\n");
561 goto fail_create_group;
564 ret = init_bios_attributes(STR, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
566 pr_debug("failed to populate string type attributes\n");
567 goto fail_create_group;
570 ret = init_bios_attributes(PO, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
572 pr_debug("failed to populate pass object type attributes\n");
573 goto fail_create_group;
579 release_attributes_data();
582 if (wmi_priv.authentication_dir_kset) {
583 kset_unregister(wmi_priv.authentication_dir_kset);
584 wmi_priv.authentication_dir_kset = NULL;
587 fail_authentication_kset:
588 if (wmi_priv.main_dir_kset) {
589 kset_unregister(wmi_priv.main_dir_kset);
590 wmi_priv.main_dir_kset = NULL;
594 device_destroy(&firmware_attributes_class, MKDEV(0, 0));
597 class_unregister(&firmware_attributes_class);
600 exit_bios_attr_pass_interface();
603 exit_bios_attr_set_interface();
609 static void __exit sysman_exit(void)
611 release_attributes_data();
612 device_destroy(&firmware_attributes_class, MKDEV(0, 0));
613 class_unregister(&firmware_attributes_class);
614 exit_bios_attr_set_interface();
615 exit_bios_attr_pass_interface();
618 module_init(sysman_init);
619 module_exit(sysman_exit);
621 MODULE_AUTHOR("Mario Limonciello <mario.limonciello@dell.com>");
622 MODULE_AUTHOR("Prasanth Ksr <prasanth.ksr@dell.com>");
623 MODULE_AUTHOR("Divya Bharathi <divya.bharathi@dell.com>");
624 MODULE_DESCRIPTION("Dell platform setting control interface");
625 MODULE_LICENSE("GPL");