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>

drivers/thunderbolt/Makefile

 obj-${CONFIG_THUNDERBOLT} := thunderbolt.o
 thunderbolt-objs := nhi.o ctl.o tb.o switch.o cap.o path.o tunnel_pci.o eeprom.o
-thunderbolt-objs += domain.o dma_port.o icm.o
+thunderbolt-objs += domain.o dma_port.o icm.o property.o

include/linux/thunderbolt.h

+/*
+ * Thunderbolt service API
+ *
+ * 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.
+ */
+
+#ifndef THUNDERBOLT_H_
+#define THUNDERBOLT_H_
+
+#include <linux/list.h>
+#include <linux/uuid.h>
+
+/**
+ * struct tb_property_dir - XDomain property directory
+ * @uuid: Directory UUID or %NULL if root directory
+ * @properties: List of properties in this directory
+ *
+ * User needs to provide serialization if needed.
+ */
+struct tb_property_dir {
+	const uuid_t *uuid;
+	struct list_head properties;
+};
+
+enum tb_property_type {
+	TB_PROPERTY_TYPE_UNKNOWN = 0x00,
+	TB_PROPERTY_TYPE_DIRECTORY = 0x44,
+	TB_PROPERTY_TYPE_DATA = 0x64,
+	TB_PROPERTY_TYPE_TEXT = 0x74,
+	TB_PROPERTY_TYPE_VALUE = 0x76,
+};
+
+#define TB_PROPERTY_KEY_SIZE	8
+
+/**
+ * struct tb_property - XDomain property
+ * @list: Used to link properties together in a directory
+ * @key: Key for the property (always terminated).
+ * @type: Type of the property
+ * @length: Length of the property data in dwords
+ * @value: Property value
+ *
+ * Users use @type to determine which field in @value is filled.
+ */
+struct tb_property {
+	struct list_head list;
+	char key[TB_PROPERTY_KEY_SIZE + 1];
+	enum tb_property_type type;
+	size_t length;
+	union {
+		struct tb_property_dir *dir;
+		u8 *data;
+		char *text;
+		u32 immediate;
+	} value;
+};
+
+struct tb_property_dir *tb_property_parse_dir(const u32 *block,
+					      size_t block_len);
+ssize_t tb_property_format_dir(const struct tb_property_dir *dir, u32 *block,
+			       size_t block_len);
+struct tb_property_dir *tb_property_create_dir(const uuid_t *uuid);
+void tb_property_free_dir(struct tb_property_dir *dir);
+int tb_property_add_immediate(struct tb_property_dir *parent, const char *key,
+			      u32 value);
+int tb_property_add_data(struct tb_property_dir *parent, const char *key,
+			 const void *buf, size_t buflen);
+int tb_property_add_text(struct tb_property_dir *parent, const char *key,
+			 const char *text);
+int tb_property_add_dir(struct tb_property_dir *parent, const char *key,
+			struct tb_property_dir *dir);
+void tb_property_remove(struct tb_property *tb_property);
+struct tb_property *tb_property_find(struct tb_property_dir *dir,
+			const char *key, enum tb_property_type type);
+struct tb_property *tb_property_get_next(struct tb_property_dir *dir,
+					 struct tb_property *prev);
+
+#define tb_property_for_each(dir, property)			\
+	for (property = tb_property_get_next(dir, NULL);	\
+	     property;						\
+	     property = tb_property_get_next(dir, property))
+
+#endif /* THUNDERBOLT_H_ */