platform/x86: Introduce support for Systems Management Driver over WMI for Dell Systems

The Dell WMI Systems Management Driver provides a sysfs
interface for systems management to enable BIOS configuration
capability on certain Dell Systems.

This driver allows user to configure Dell systems with a
uniform common interface. To facilitate this, the patch
introduces a generic way for driver to be able to create
configurable BIOS Attributes available in Setup (F2) screen.

Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: mark gross <mgross@linux.intel.com>

Co-developed-by: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Co-developed-by: Prasanth KSR <prasanth.ksr@dell.com>
Signed-off-by: Prasanth KSR <prasanth.ksr@dell.com>
Signed-off-by: Divya Bharathi <divya.bharathi@dell.com>
Link: https://lore.kernel.org/r/20201027134944.316730-1-divya.bharathi@dell.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 159 insertions, 0 deletions

diff --git a/drivers/platform/x86/dell-wmi-sysman/string-attributes.c b/drivers/platform/x86/dell-wmi-sysman/string-attributes.c
new file mode 100644
index 000000000000..ac75dce88a4c
--- /dev/null
+++ b/drivers/platform/x86/dell-wmi-sysman/string-attributes.c
@@ -0,0 +1,159 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions corresponding to string type attributes under BIOS String GUID for use with
+ * dell-wmi-sysman
+ *
+ *  Copyright (c) 2020 Dell Inc.
+ */
+
+#include "dell-wmi-sysman.h"
+
+enum string_properties {MIN_LEN = 6, MAX_LEN};
+
+get_instance_id(str);
+
+static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	int instance_id = get_str_instance_id(kobj);
+	union acpi_object *obj;
+	ssize_t ret;
+
+	if (instance_id < 0)
+		return -EIO;
+
+	/* need to use specific instance_id and guid combination to get right data */
+	obj = get_wmiobj_pointer(instance_id, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
+	if (!obj)
+		return -EIO;
+	if (obj->package.elements[CURRENT_VAL].type != ACPI_TYPE_STRING) {
+		kfree(obj);
+		return -EINVAL;
+	}
+	ret = snprintf(buf, PAGE_SIZE, "%s\n", obj->package.elements[CURRENT_VAL].string.pointer);
+	kfree(obj);
+	return ret;
+}
+
+/**
+ * validate_str_input() - Validate input of current_value against min and max lengths
+ * @instance_id: The instance on which input is validated
+ * @buf: Input value
+ */
+static int validate_str_input(int instance_id, const char *buf)
+{
+	int in_len = strlen(buf);
+
+	if ((in_len < wmi_priv.str_data[instance_id].min_length) ||
+			(in_len > wmi_priv.str_data[instance_id].max_length))
+		return -EINVAL;
+
+	return 0;
+}
+
+attribute_s_property_show(display_name_language_code, str);
+static struct kobj_attribute str_displ_langcode =
+		__ATTR_RO(display_name_language_code);
+
+attribute_s_property_show(display_name, str);
+static struct kobj_attribute str_displ_name =
+		__ATTR_RO(display_name);
+
+attribute_s_property_show(default_value, str);
+static struct kobj_attribute str_default_val =
+		__ATTR_RO(default_value);
+
+attribute_property_store(current_value, str);
+static struct kobj_attribute str_current_val =
+		__ATTR_RW_MODE(current_value, 0600);
+
+attribute_s_property_show(dell_modifier, str);
+static struct kobj_attribute str_modifier =
+		__ATTR_RO(dell_modifier);
+
+attribute_n_property_show(min_length, str);
+static struct kobj_attribute str_min_length =
+		__ATTR_RO(min_length);
+
+attribute_n_property_show(max_length, str);
+static struct kobj_attribute str_max_length =
+		__ATTR_RO(max_length);
+
+static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr,
+			 char *buf)
+{
+	return sprintf(buf, "string\n");
+}
+static struct kobj_attribute str_type =
+	__ATTR_RO(type);
+
+static struct attribute *str_attrs[] = {
+	&str_displ_langcode.attr,
+	&str_displ_name.attr,
+	&str_default_val.attr,
+	&str_current_val.attr,
+	&str_modifier.attr,
+	&str_min_length.attr,
+	&str_max_length.attr,
+	&str_type.attr,
+	NULL,
+};
+
+static const struct attribute_group str_attr_group = {
+	.attrs = str_attrs,
+};
+
+int alloc_str_data(void)
+{
+	int ret = 0;
+
+	wmi_priv.str_instances_count = get_instance_count(DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
+	wmi_priv.str_data = kcalloc(wmi_priv.str_instances_count,
+					sizeof(struct str_data), GFP_KERNEL);
+	if (!wmi_priv.str_data) {
+		wmi_priv.str_instances_count = 0;
+		ret = -ENOMEM;
+	}
+	return ret;
+}
+
+/**
+ * populate_str_data() - Populate all properties of an instance under string attribute
+ * @str_obj: ACPI object with integer data
+ * @instance_id: The instance to enumerate
+ * @attr_name_kobj: The parent kernel object
+ */
+int populate_str_data(union acpi_object *str_obj, int instance_id, struct kobject *attr_name_kobj)
+{
+	wmi_priv.str_data[instance_id].attr_name_kobj = attr_name_kobj;
+	strlcpy_attr(wmi_priv.str_data[instance_id].attribute_name,
+		     str_obj[ATTR_NAME].string.pointer);
+	strlcpy_attr(wmi_priv.str_data[instance_id].display_name_language_code,
+		     str_obj[DISPL_NAME_LANG_CODE].string.pointer);
+	strlcpy_attr(wmi_priv.str_data[instance_id].display_name,
+		     str_obj[DISPLAY_NAME].string.pointer);
+	strlcpy_attr(wmi_priv.str_data[instance_id].default_value,
+		     str_obj[DEFAULT_VAL].string.pointer);
+	strlcpy_attr(wmi_priv.str_data[instance_id].dell_modifier,
+		     str_obj[MODIFIER].string.pointer);
+	wmi_priv.str_data[instance_id].min_length = (uintptr_t)str_obj[MIN_LEN].string.pointer;
+	wmi_priv.str_data[instance_id].max_length = (uintptr_t) str_obj[MAX_LEN].string.pointer;
+
+	return sysfs_create_group(attr_name_kobj, &str_attr_group);
+}
+
+/**
+ * exit_str_attributes() - Clear all attribute data
+ *
+ * Clears all data allocated for this group of attributes
+ */
+void exit_str_attributes(void)
+{
+	int instance_id;
+
+	for (instance_id = 0; instance_id < wmi_priv.str_instances_count; instance_id++) {
+		if (wmi_priv.str_data[instance_id].attr_name_kobj)
+			sysfs_remove_group(wmi_priv.str_data[instance_id].attr_name_kobj,
+								&str_attr_group);
+	}
+	kfree(wmi_priv.str_data);
+}