thunderbolt: Add support for XDomain properties

Thunderbolt XDomain discovery protocol uses directories which contain
properties and other directories to exchange information about what
capabilities the remote host supports. This also includes identification
information like device ID and name.

This adds support for parsing and formatting these properties and
establishes an API drivers can use in addition to the core Thunderbolt
driver. This API is exposed in a new header: include/linux/thunderbolt.h.

This code is based on the work done by Amir Levy and Michael Jamet.

Signed-off-by: Michael Jamet <michael.jamet@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 670 insertions, 0 deletions

diff --git a/drivers/thunderbolt/property.c b/drivers/thunderbolt/property.c
new file mode 100644
index 000000000000..8fe913a95b4a
--- /dev/null
+++ b/drivers/thunderbolt/property.c
@@ -0,0 +1,670 @@
+/*
+ * Thunderbolt XDomain property support
+ *
+ * Copyright (C) 2017, Intel Corporation
+ * Authors: Michael Jamet <michael.jamet@intel.com>
+ *          Mika Westerberg <mika.westerberg@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/err.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
+
+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);
+
+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)
+{
+	switch (entry->type) {
+	case TB_PROPERTY_TYPE_DIRECTORY:
+	case TB_PROPERTY_TYPE_DATA:
+	case TB_PROPERTY_TYPE_TEXT:
+		if (entry->length > block_len)
+			return false;
+		if (entry->value + entry->length > 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(sizeof(*property), GFP_KERNEL);
+	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)
+{
+	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);
+		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)
+{
+	const struct tb_property_entry *entries;
+	size_t i, content_len, nentries;
+	unsigned int content_offset;
+	struct tb_property_dir *dir;
+
+	dir = kzalloc(sizeof(*dir), GFP_KERNEL);
+	if (!dir)
+		return NULL;
+
+	if (is_root) {
+		content_offset = dir_offset + 2;
+		content_len = dir_len;
+	} else {
+		dir->uuid = kmemdup(&block[dir_offset], sizeof(*dir->uuid),
+				    GFP_KERNEL);
+		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);
+
+	INIT_LIST_HEAD(&dir->properties);
+
+	for (i = 0; i < nentries; i++) {
+		struct tb_property *property;
+
+		property = tb_property_parse(block, block_len, &entries[i]);
+		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.
+ * Upon success returns the parsed directory. In case of error returns
+ * %NULL. 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.
+ */
+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);
+}
+
+/**
+ * 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.
+ */
+struct tb_property_dir *tb_property_create_dir(const uuid_t *uuid)
+{
+	struct tb_property_dir *dir;
+
+	dir = kzalloc(sizeof(*dir), GFP_KERNEL);
+	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 send over the thunderbolt fabric to receiving host. Returns %0 in
+ * case of success and negative errno on faulure. Passing %NULL in @block
+ * returns number of entries the block takes.
+ */
+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;
+}
+
+/**
+ * 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
+ */
+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.
+ */
+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);
+	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.
+ */
+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.data = kzalloc(size, GFP_KERNEL);
+	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
+ */
+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. Returns %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)
+ */
+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);