drm/amd/display: Try RGB before YCbCr 4:4:4 in stream validationgrafted

amdgpu_dm_create_validate_stream_for_sink() walks encoding_order[] and
uses the first encoding that validates. YCbCr 4:4:4 is listed before
RGB, so an HDMI sink that advertises 4:4:4 gets YCbCr 4:4:4 whenever the
"color format" property is left at AUTO, even though RGB fits the same
link.

That contradicts the documented AUTO behaviour for HDMI in enum
drm_connector_color_format (RGB, falling back to YCbCr 4:2:0 only when
the bandwidth is not available or the mode is 4:2:0-only), which the
amdgpu implementation of the property also describes. It also leaves
the "Broadcast RGB" property without effect on such sinks, since the
quantization range it selects only applies to RGB output.

Try RGB first. The mask still holds every encoding the sink supports,
so a mode that cannot carry RGB falls back exactly as before.

For reference, v7.2 picked RGB here unless YCbCr 4:4:4 was forced
through debugfs, while earlier kernels picked YCbCr 4:4:4 for any HDMI
sink that advertised it.

Fixes: 0b0ff65d3ca1 ("drm/amd/display: Refactor stream validation")
Suggested-by: Adolfo Rodrigues <adolfotregosa@gmail.com>
Assisted-by: Claude Code:claude-fable-5-1
Signed-off-by: Adrian Betschart <adrian.betschart@cinemaone.ch>
Reviewed-by: Fangzhi Zuo <jerry.zuo@amd.com>
Tested-by: Adolfo Rodrigues <adolfotregosa@gmail.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 7de432bc753133764dc40d37f9388da56de251e7)

1 files changed, 858 insertions, 0 deletions

diff --git a/drivers/thunderbolt/property.c b/drivers/thunderbolt/property.c
new file mode 100644
index 000000000..df18a6d69
--- /dev/null
+++ b/drivers/thunderbolt/property.c
@@ -0,0 +1,858 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Thunderbolt XDomain property support
+ *
+ * Copyright (C) 2017, Intel Corporation
+ * Authors: Michael Jamet <michael.jamet@intel.com>
+ *          Mika Westerberg <mika.westerberg@linux.intel.com>
+ */
+
+#include <linux/err.h>
+#include <linux/overflow.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/uuid.h>
+#include <linux/thunderbolt.h>
+
+struct tb_property_entry {
+	u32 key_hi;
+	u32 key_lo;
+	u16 length;
+	u8 reserved;
+	u8 type;
+	u32 value;
+};
+
+struct tb_property_rootdir_entry {
+	u32 magic;
+	u32 length;
+	struct tb_property_entry entries[];
+};
+
+struct tb_property_dir_entry {
+	u32 uuid[4];
+	struct tb_property_entry entries[];
+};
+
+#define TB_PROPERTY_ROOTDIR_MAGIC	0x55584401
+#define TB_PROPERTY_MAX_DEPTH		8
+
+static struct tb_property_dir *__tb_property_parse_dir(const u32 *block,
+	size_t block_len, unsigned int dir_offset, size_t dir_len,
+	bool is_root, unsigned int depth);
+static struct tb_property *tb_property_copy(const struct tb_property *property);
+
+static inline void parse_dwdata(void *dst, const void *src, size_t dwords)
+{
+	be32_to_cpu_array(dst, src, dwords);
+}
+
+static inline void format_dwdata(void *dst, const void *src, size_t dwords)
+{
+	cpu_to_be32_array(dst, src, dwords);
+}
+
+static bool tb_property_entry_valid(const struct tb_property_entry *entry,
+				  size_t block_len)
+{
+	u32 end;
+
+	switch (entry->type) {
+	case TB_PROPERTY_TYPE_DIRECTORY:
+	case TB_PROPERTY_TYPE_DATA:
+	case TB_PROPERTY_TYPE_TEXT:
+		if (!entry->length)
+			return false;
+		if (entry->length > block_len)
+			return false;
+		if (check_add_overflow(entry->value, entry->length, &end) ||
+		    end > block_len)
+			return false;
+		break;
+
+	case TB_PROPERTY_TYPE_VALUE:
+		if (entry->length != 1)
+			return false;
+		break;
+	}
+
+	return true;
+}
+
+static bool tb_property_key_valid(const char *key)
+{
+	return key && strlen(key) <= TB_PROPERTY_KEY_SIZE;
+}
+
+static struct tb_property *
+tb_property_alloc(const char *key, enum tb_property_type type)
+{
+	struct tb_property *property;
+
+	property = kzalloc_obj(*property);
+	if (!property)
+		return NULL;
+
+	strcpy(property->key, key);
+	property->type = type;
+	INIT_LIST_HEAD(&property->list);
+
+	return property;
+}
+
+static struct tb_property *tb_property_parse(const u32 *block, size_t block_len,
+					const struct tb_property_entry *entry,
+					unsigned int depth)
+{
+	char key[TB_PROPERTY_KEY_SIZE + 1];
+	struct tb_property *property;
+	struct tb_property_dir *dir;
+
+	if (!tb_property_entry_valid(entry, block_len))
+		return NULL;
+
+	parse_dwdata(key, entry, 2);
+	key[TB_PROPERTY_KEY_SIZE] = '\0';
+
+	property = tb_property_alloc(key, entry->type);
+	if (!property)
+		return NULL;
+
+	property->length = entry->length;
+
+	switch (property->type) {
+	case TB_PROPERTY_TYPE_DIRECTORY:
+		dir = __tb_property_parse_dir(block, block_len, entry->value,
+					      entry->length, false, depth + 1);
+		if (!dir) {
+			kfree(property);
+			return NULL;
+		}
+		property->value.dir = dir;
+		break;
+
+	case TB_PROPERTY_TYPE_DATA:
+		property->value.data = kcalloc(property->length, sizeof(u32),
+					       GFP_KERNEL);
+		if (!property->value.data) {
+			kfree(property);
+			return NULL;
+		}
+		parse_dwdata(property->value.data, block + entry->value,
+			     entry->length);
+		break;
+
+	case TB_PROPERTY_TYPE_TEXT:
+		property->value.text = kcalloc(property->length, sizeof(u32),
+					       GFP_KERNEL);
+		if (!property->value.text) {
+			kfree(property);
+			return NULL;
+		}
+		parse_dwdata(property->value.text, block + entry->value,
+			     entry->length);
+		/* Force null termination */
+		property->value.text[property->length * 4 - 1] = '\0';
+		break;
+
+	case TB_PROPERTY_TYPE_VALUE:
+		property->value.immediate = entry->value;
+		break;
+
+	default:
+		property->type = TB_PROPERTY_TYPE_UNKNOWN;
+		break;
+	}
+
+	return property;
+}
+
+static struct tb_property_dir *__tb_property_parse_dir(const u32 *block,
+	size_t block_len, unsigned int dir_offset, size_t dir_len, bool is_root,
+	unsigned int depth)
+{
+	const struct tb_property_entry *entries;
+	size_t i, content_len, nentries;
+	unsigned int content_offset;
+	struct tb_property_dir *dir;
+
+	if (depth > TB_PROPERTY_MAX_DEPTH)
+		return NULL;
+
+	dir = kzalloc_obj(*dir);
+	if (!dir)
+		return NULL;
+
+	INIT_LIST_HEAD(&dir->properties);
+
+	if (is_root) {
+		content_offset = dir_offset + 2;
+		content_len = dir_len;
+		if (content_offset + content_len > block_len) {
+			tb_property_free_dir(dir);
+			return NULL;
+		}
+	} else {
+		if (dir_len < 4) {
+			tb_property_free_dir(dir);
+			return NULL;
+		}
+		dir->uuid = kmemdup(&block[dir_offset], sizeof(*dir->uuid),
+				    GFP_KERNEL);
+		if (!dir->uuid) {
+			tb_property_free_dir(dir);
+			return NULL;
+		}
+		content_offset = dir_offset + 4;
+		content_len = dir_len - 4; /* Length includes UUID */
+	}
+
+	entries = (const struct tb_property_entry *)&block[content_offset];
+	nentries = content_len / (sizeof(*entries) / 4);
+
+	for (i = 0; i < nentries; i++) {
+		struct tb_property *property;
+
+		property = tb_property_parse(block, block_len, &entries[i], depth);
+		if (!property) {
+			tb_property_free_dir(dir);
+			return NULL;
+		}
+
+		list_add_tail(&property->list, &dir->properties);
+	}
+
+	return dir;
+}
+
+/**
+ * tb_property_parse_dir() - Parses properties from given property block
+ * @block: Property block to parse
+ * @block_len: Number of dword elements in the property block
+ *
+ * This function parses the XDomain properties data block into format that
+ * can be traversed using the helper functions provided by this module.
+ *
+ * The resulting &struct tb_property_dir needs to be released by
+ * calling tb_property_free_dir() when not needed anymore.
+ *
+ * The @block is expected to be root directory.
+ *
+ * Return: Pointer to &struct tb_property_dir, %NULL in case of failure.
+ */
+struct tb_property_dir *tb_property_parse_dir(const u32 *block,
+					      size_t block_len)
+{
+	const struct tb_property_rootdir_entry *rootdir =
+		(const struct tb_property_rootdir_entry *)block;
+
+	if (rootdir->magic != TB_PROPERTY_ROOTDIR_MAGIC)
+		return NULL;
+	if (rootdir->length > block_len)
+		return NULL;
+
+	return __tb_property_parse_dir(block, block_len, 0, rootdir->length,
+				       true, 0);
+}
+
+/**
+ * tb_property_create_dir() - Creates new property directory
+ * @uuid: UUID used to identify the particular directory
+ *
+ * Creates new, empty property directory. If @uuid is %NULL then the
+ * directory is assumed to be root directory.
+ *
+ * Return: Pointer to &struct tb_property_dir, %NULL in case of failure.
+ */
+struct tb_property_dir *tb_property_create_dir(const uuid_t *uuid)
+{
+	struct tb_property_dir *dir;
+
+	dir = kzalloc_obj(*dir);
+	if (!dir)
+		return NULL;
+
+	INIT_LIST_HEAD(&dir->properties);
+	if (uuid) {
+		dir->uuid = kmemdup(uuid, sizeof(*dir->uuid), GFP_KERNEL);
+		if (!dir->uuid) {
+			kfree(dir);
+			return NULL;
+		}
+	}
+
+	return dir;
+}
+EXPORT_SYMBOL_GPL(tb_property_create_dir);
+
+static void tb_property_free(struct tb_property *property)
+{
+	switch (property->type) {
+	case TB_PROPERTY_TYPE_DIRECTORY:
+		tb_property_free_dir(property->value.dir);
+		break;
+
+	case TB_PROPERTY_TYPE_DATA:
+		kfree(property->value.data);
+		break;
+
+	case TB_PROPERTY_TYPE_TEXT:
+		kfree(property->value.text);
+		break;
+
+	default:
+		break;
+	}
+
+	kfree(property);
+}
+
+/**
+ * tb_property_free_dir() - Release memory allocated for property directory
+ * @dir: Directory to release
+ *
+ * This will release all the memory the directory occupies including all
+ * descendants. It is OK to pass %NULL @dir, then the function does
+ * nothing.
+ */
+void tb_property_free_dir(struct tb_property_dir *dir)
+{
+	struct tb_property *property, *tmp;
+
+	if (!dir)
+		return;
+
+	list_for_each_entry_safe(property, tmp, &dir->properties, list) {
+		list_del(&property->list);
+		tb_property_free(property);
+	}
+	kfree(dir->uuid);
+	kfree(dir);
+}
+EXPORT_SYMBOL_GPL(tb_property_free_dir);
+
+static size_t tb_property_dir_length(const struct tb_property_dir *dir,
+				     bool recurse, size_t *data_len)
+{
+	const struct tb_property *property;
+	size_t len = 0;
+
+	if (dir->uuid)
+		len += sizeof(*dir->uuid) / 4;
+	else
+		len += sizeof(struct tb_property_rootdir_entry) / 4;
+
+	list_for_each_entry(property, &dir->properties, list) {
+		len += sizeof(struct tb_property_entry) / 4;
+
+		switch (property->type) {
+		case TB_PROPERTY_TYPE_DIRECTORY:
+			if (recurse) {
+				len += tb_property_dir_length(
+					property->value.dir, recurse, data_len);
+			}
+			/* Reserve dword padding after each directory */
+			if (data_len)
+				*data_len += 1;
+			break;
+
+		case TB_PROPERTY_TYPE_DATA:
+		case TB_PROPERTY_TYPE_TEXT:
+			if (data_len)
+				*data_len += property->length;
+			break;
+
+		default:
+			break;
+		}
+	}
+
+	return len;
+}
+
+static ssize_t __tb_property_format_dir(const struct tb_property_dir *dir,
+	u32 *block, unsigned int start_offset, size_t block_len)
+{
+	unsigned int data_offset, dir_end;
+	const struct tb_property *property;
+	struct tb_property_entry *entry;
+	size_t dir_len, data_len = 0;
+	int ret;
+
+	/*
+	 * The structure of property block looks like following. Leaf
+	 * data/text is included right after the directory and each
+	 * directory follows each other (even nested ones).
+	 *
+	 * +----------+ <-- start_offset
+	 * |  header  | <-- root directory header
+	 * +----------+ ---
+	 * |  entry 0 | -^--------------------.
+	 * +----------+  |                    |
+	 * |  entry 1 | -|--------------------|--.
+	 * +----------+  |                    |  |
+	 * |  entry 2 | -|-----------------.  |  |
+	 * +----------+  |                 |  |  |
+	 * :          :  |  dir_len        |  |  |
+	 * .          .  |                 |  |  |
+	 * :          :  |                 |  |  |
+	 * +----------+  |                 |  |  |
+	 * |  entry n |  v                 |  |  |
+	 * +----------+ <-- data_offset    |  |  |
+	 * |  data 0  | <------------------|--'  |
+	 * +----------+                    |     |
+	 * |  data 1  | <------------------|-----'
+	 * +----------+                    |
+	 * | 00000000 | padding            |
+	 * +----------+ <-- dir_end <------'
+	 * |   UUID   | <-- directory UUID (child directory)
+	 * +----------+
+	 * |  entry 0 |
+	 * +----------+
+	 * |  entry 1 |
+	 * +----------+
+	 * :          :
+	 * .          .
+	 * :          :
+	 * +----------+
+	 * |  entry n |
+	 * +----------+
+	 * |  data 0  |
+	 * +----------+
+	 *
+	 * We use dir_end to hold pointer to the end of the directory. It
+	 * will increase as we add directories and each directory should be
+	 * added starting from previous dir_end.
+	 */
+	dir_len = tb_property_dir_length(dir, false, &data_len);
+	data_offset = start_offset + dir_len;
+	dir_end = start_offset + data_len + dir_len;
+
+	if (data_offset > dir_end)
+		return -EINVAL;
+	if (dir_end > block_len)
+		return -EINVAL;
+
+	/* Write headers first */
+	if (dir->uuid) {
+		struct tb_property_dir_entry *pe;
+
+		pe = (struct tb_property_dir_entry *)&block[start_offset];
+		memcpy(pe->uuid, dir->uuid, sizeof(pe->uuid));
+		entry = pe->entries;
+	} else {
+		struct tb_property_rootdir_entry *re;
+
+		re = (struct tb_property_rootdir_entry *)&block[start_offset];
+		re->magic = TB_PROPERTY_ROOTDIR_MAGIC;
+		re->length = dir_len - sizeof(*re) / 4;
+		entry = re->entries;
+	}
+
+	list_for_each_entry(property, &dir->properties, list) {
+		const struct tb_property_dir *child;
+
+		format_dwdata(entry, property->key, 2);
+		entry->type = property->type;
+
+		switch (property->type) {
+		case TB_PROPERTY_TYPE_DIRECTORY:
+			child = property->value.dir;
+			ret = __tb_property_format_dir(child, block, dir_end,
+						       block_len);
+			if (ret < 0)
+				return ret;
+			entry->length = tb_property_dir_length(child, false,
+							       NULL);
+			entry->value = dir_end;
+			dir_end = ret;
+			break;
+
+		case TB_PROPERTY_TYPE_DATA:
+			format_dwdata(&block[data_offset], property->value.data,
+				      property->length);
+			entry->length = property->length;
+			entry->value = data_offset;
+			data_offset += entry->length;
+			break;
+
+		case TB_PROPERTY_TYPE_TEXT:
+			format_dwdata(&block[data_offset], property->value.text,
+				      property->length);
+			entry->length = property->length;
+			entry->value = data_offset;
+			data_offset += entry->length;
+			break;
+
+		case TB_PROPERTY_TYPE_VALUE:
+			entry->length = property->length;
+			entry->value = property->value.immediate;
+			break;
+
+		default:
+			break;
+		}
+
+		entry++;
+	}
+
+	return dir_end;
+}
+
+/**
+ * tb_property_format_dir() - Formats directory to the packed XDomain format
+ * @dir: Directory to format
+ * @block: Property block where the packed data is placed
+ * @block_len: Length of the property block
+ *
+ * This function formats the directory to the packed format that can be
+ * then sent over the thunderbolt fabric to receiving host.
+ *
+ * Passing %NULL in @block returns number of entries the block takes.
+ *
+ * Return: %0 on success, negative errno otherwise.
+ */
+ssize_t tb_property_format_dir(const struct tb_property_dir *dir, u32 *block,
+			       size_t block_len)
+{
+	ssize_t ret;
+
+	if (!block) {
+		size_t dir_len, data_len = 0;
+
+		dir_len = tb_property_dir_length(dir, true, &data_len);
+		return dir_len + data_len;
+	}
+
+	ret = __tb_property_format_dir(dir, block, 0, block_len);
+	return ret < 0 ? ret : 0;
+}
+
+static struct tb_property_dir *copy_dir(const struct tb_property_dir *dir)
+{
+	struct tb_property *property, *p;
+	struct tb_property_dir *d;
+
+	if (!dir)
+		return NULL;
+
+	d = tb_property_create_dir(dir->uuid);
+	if (!d)
+		return NULL;
+
+	list_for_each_entry(property, &dir->properties, list) {
+		p = tb_property_copy(property);
+		if (!p)
+			goto err_free;
+		list_add_tail(&p->list, &d->properties);
+	}
+
+	return d;
+
+err_free:
+	tb_property_free_dir(d);
+	return NULL;
+}
+
+static struct tb_property *tb_property_copy(const struct tb_property *property)
+{
+	struct tb_property *p;
+
+	p = tb_property_alloc(property->key, property->type);
+	if (!p)
+		return NULL;
+
+	p->length = property->length;
+	switch (property->type) {
+	case TB_PROPERTY_TYPE_DIRECTORY:
+		p->value.dir = copy_dir(property->value.dir);
+		if (!p->value.dir)
+			goto err_free;
+		break;
+
+	case TB_PROPERTY_TYPE_DATA:
+		p->value.data = kmemdup(property->value.data,
+					property->length * 4,
+					GFP_KERNEL);
+		if (!p->value.data)
+			goto err_free;
+		break;
+
+	case TB_PROPERTY_TYPE_TEXT:
+		p->value.text = kzalloc(p->length * 4, GFP_KERNEL);
+		if (!p->value.text)
+			goto err_free;
+		strcpy(p->value.text, property->value.text);
+		break;
+
+	case TB_PROPERTY_TYPE_VALUE:
+		p->value.immediate = property->value.immediate;
+		break;
+
+	default:
+		break;
+	}
+
+	return p;
+
+err_free:
+	kfree(p);
+	return NULL;
+}
+
+/**
+ * tb_property_copy_dir() - Take a deep copy of directory
+ * @dir: Directory to copy
+ *
+ * The resulting directory needs to be released by calling tb_property_free_dir().
+ *
+ * Return: Pointer to &struct tb_property_dir, %NULL in case of failure.
+ */
+struct tb_property_dir *tb_property_copy_dir(const struct tb_property_dir *dir)
+{
+	return copy_dir(dir);
+}
+EXPORT_SYMBOL_GPL(tb_property_copy_dir);
+
+/**
+ * tb_property_merge_dir() - Merges directory into parent
+ * @parent: Directory to merge @dir
+ * @dir: Directory that is merged
+ * @replace: Replace existing entries
+ *
+ * This will merge @dir into @parent. Both must have same UUID. The
+ * properties in @dir will overwrite overlapping properties in @parent
+ * if @replace is %true. Contents of @dir is copied (so if it is not
+ * needed afterwards it needs to relesed by calling tb_property_free_dir()).
+ */
+int tb_property_merge_dir(struct tb_property_dir *parent,
+			  const struct tb_property_dir *dir,
+			  bool replace)
+{
+	const struct tb_property *property;
+
+	if (WARN_ON(parent == dir))
+		return -EINVAL;
+
+	if (!uuid_equal(parent->uuid, dir->uuid))
+		return -EINVAL;
+
+	list_for_each_entry(property, &dir->properties, list) {
+		struct tb_property *p, *tmp;
+
+		tmp = tb_property_copy(property);
+		if (!tmp)
+			return -ENOMEM;
+
+		p = tb_property_find(parent, property->key, property->type);
+		if (p) {
+			if (replace) {
+				/*
+				 * Found existing property in parent so
+				 * replace with the new one.
+				 */
+				list_replace(&p->list, &tmp->list);
+				tb_property_free(p);
+			} else {
+				tb_property_free(tmp);
+				continue;
+			}
+		} else {
+			list_add_tail(&tmp->list, &parent->properties);
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(tb_property_merge_dir);
+
+/**
+ * tb_property_add_immediate() - Add immediate property to directory
+ * @parent: Directory to add the property
+ * @key: Key for the property
+ * @value: Immediate value to store with the property
+ *
+ * Return: %0 on success, negative errno otherwise.
+ */
+int tb_property_add_immediate(struct tb_property_dir *parent, const char *key,
+			      u32 value)
+{
+	struct tb_property *property;
+
+	if (!tb_property_key_valid(key))
+		return -EINVAL;
+
+	property = tb_property_alloc(key, TB_PROPERTY_TYPE_VALUE);
+	if (!property)
+		return -ENOMEM;
+
+	property->length = 1;
+	property->value.immediate = value;
+
+	list_add_tail(&property->list, &parent->properties);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(tb_property_add_immediate);
+
+/**
+ * tb_property_add_data() - Adds arbitrary data property to directory
+ * @parent: Directory to add the property
+ * @key: Key for the property
+ * @buf: Data buffer to add
+ * @buflen: Number of bytes in the data buffer
+ *
+ * Function takes a copy of @buf and adds it to the directory.
+ *
+ * Return: %0 on success, negative errno otherwise.
+ */
+int tb_property_add_data(struct tb_property_dir *parent, const char *key,
+			 const void *buf, size_t buflen)
+{
+	/* Need to pad to dword boundary */
+	size_t size = round_up(buflen, 4);
+	struct tb_property *property;
+
+	if (!tb_property_key_valid(key))
+		return -EINVAL;
+
+	property = tb_property_alloc(key, TB_PROPERTY_TYPE_DATA);
+	if (!property)
+		return -ENOMEM;
+
+	property->length = size / 4;
+	property->value.data = kzalloc(size, GFP_KERNEL);
+	if (!property->value.data) {
+		kfree(property);
+		return -ENOMEM;
+	}
+
+	memcpy(property->value.data, buf, buflen);
+
+	list_add_tail(&property->list, &parent->properties);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(tb_property_add_data);
+
+/**
+ * tb_property_add_text() - Adds string property to directory
+ * @parent: Directory to add the property
+ * @key: Key for the property
+ * @text: String to add
+ *
+ * Function takes a copy of @text and adds it to the directory.
+ *
+ * Return: %0 on success, negative errno otherwise.
+ */
+int tb_property_add_text(struct tb_property_dir *parent, const char *key,
+			 const char *text)
+{
+	/* Need to pad to dword boundary */
+	size_t size = round_up(strlen(text) + 1, 4);
+	struct tb_property *property;
+
+	if (!tb_property_key_valid(key))
+		return -EINVAL;
+
+	property = tb_property_alloc(key, TB_PROPERTY_TYPE_TEXT);
+	if (!property)
+		return -ENOMEM;
+
+	property->length = size / 4;
+	property->value.text = kzalloc(size, GFP_KERNEL);
+	if (!property->value.text) {
+		kfree(property);
+		return -ENOMEM;
+	}
+
+	strcpy(property->value.text, text);
+
+	list_add_tail(&property->list, &parent->properties);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(tb_property_add_text);
+
+/**
+ * tb_property_add_dir() - Adds a directory to the parent directory
+ * @parent: Directory to add the property
+ * @key: Key for the property
+ * @dir: Directory to add
+ *
+ * Return: %0 on success, negative errno otherwise.
+ */
+int tb_property_add_dir(struct tb_property_dir *parent, const char *key,
+			struct tb_property_dir *dir)
+{
+	struct tb_property *property;
+
+	if (!tb_property_key_valid(key))
+		return -EINVAL;
+
+	property = tb_property_alloc(key, TB_PROPERTY_TYPE_DIRECTORY);
+	if (!property)
+		return -ENOMEM;
+
+	property->value.dir = dir;
+
+	list_add_tail(&property->list, &parent->properties);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(tb_property_add_dir);
+
+/**
+ * tb_property_remove() - Removes property from a parent directory
+ * @property: Property to remove
+ *
+ * Note memory for @property is released as well so it is not allowed to
+ * touch the object after call to this function.
+ */
+void tb_property_remove(struct tb_property *property)
+{
+	list_del(&property->list);
+	kfree(property);
+}
+EXPORT_SYMBOL_GPL(tb_property_remove);
+
+/**
+ * tb_property_find() - Find a property from a directory
+ * @dir: Directory where the property is searched
+ * @key: Key to look for
+ * @type: Type of the property
+ *
+ * Finds and returns property from the given directory. Does not
+ * recurse into sub-directories.
+ *
+ * Return: Pointer to &struct tb_property, %NULL if the property was not found.
+ */
+struct tb_property *tb_property_find(struct tb_property_dir *dir,
+	const char *key, enum tb_property_type type)
+{
+	struct tb_property *property;
+
+	list_for_each_entry(property, &dir->properties, list) {
+		if (property->type == type && !strcmp(property->key, key))
+			return property;
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(tb_property_find);
+
+/**
+ * tb_property_get_next() - Get next property from directory
+ * @dir: Directory holding properties
+ * @prev: Previous property in the directory (%NULL returns the first)
+ *
+ * Return: Pointer to &struct tb_property, %NULL if property was not found.
+ */
+struct tb_property *tb_property_get_next(struct tb_property_dir *dir,
+					 struct tb_property *prev)
+{
+	if (prev) {
+		if (list_is_last(&prev->list, &dir->properties))
+			return NULL;
+		return list_next_entry(prev, list);
+	}
+	return list_first_entry_or_null(&dir->properties, struct tb_property,
+					list);
+}
+EXPORT_SYMBOL_GPL(tb_property_get_next);