Bluetooth: Audio: Media proxy

This commit adds the media proxy from the topic-le-audio branch.
This is a part of the upmerge of the le-audio media control files.

The media proxy adds a common API to register and access local media
players, and to discover and access remote media players over
bluetooth using the media control client and a remote media control
service.

The commit is a pure copy of the files and content in the
topic-le-audio branch, with the following exceptions:

- files are in bluetooth/audio instead of bluetooth/host/audio, with
  some include paths updated as a consequence
- as a consequence, CMake files and Kconfig files updates are done in
  other locations

Signed-off-by: Asbjørn Sæbø <asbjorn.sabo@nordicsemi.no>

subsys/bluetooth/audio/CMakeLists.txt

@@ -35,3 +35,5 @@ endif()
 zephyr_library_sources_ifdef(CONFIG_BT_OTC otc.c)
 
 zephyr_library_sources_ifdef(CONFIG_BT_MCC mcc.c)
+
+zephyr_library_sources_ifdef(CONFIG_BT_MCS media_proxy.c)

subsys/bluetooth/audio/media_proxy_internal.h

@@ -0,0 +1,129 @@
+/*
+ * Copyright (c) 2021 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_SUBSYS_BLUETOOTH_AUDIO_MEDIA_PROXY_INTERNAL_H_
+#define ZEPHYR_SUBSYS_BLUETOOTH_AUDIO_MEDIA_PROXY_INTERNAL_H_
+
+/** @brief Internal APIs for Bluetooth Media Control */
+
+#include <bluetooth/audio/media_proxy.h>
+
+#define MPL_NO_TRACK_ID 0
+
+/* Debug output of 48 bit Object ID value */
+/* (Zephyr does not yet support debug output of more than 32 bit values.) */
+/* Takes a text and a 64-bit integer as input */
+#define BT_DBG_OBJ_ID(text, id64) \
+	do { \
+		if (IS_ENABLED(CONFIG_BT_DEBUG_MCS)) { \
+			char t[BT_OTS_OBJ_ID_STR_LEN]; \
+			(void)bt_ots_obj_id_to_str(id64, t, sizeof(t)); \
+			BT_DBG(text "0x%s", log_strdup(t)); \
+		} \
+	} while (0)
+
+
+/* SYNCHRONOUS (CALL/RETURN) API FOR CONTROLLERS */
+
+/** @brief Callbacks to a controller, from the media proxy */
+struct media_proxy_sctrl_cbs {
+
+	void (*track_changed)(void);
+
+	void (*track_title)(const char *title);
+
+	void (*track_duration)(int32_t duration);
+
+	void (*track_position)(int32_t position);
+
+	void (*playback_speed)(int8_t speed);
+
+	void (*seeking_speed)(int8_t speed);
+#ifdef CONFIG_BT_OTS
+	void (*current_track_id)(uint64_t id);
+
+	void (*next_track_id)(uint64_t id);
+
+	void (*current_group_id)(uint64_t id);
+
+	void (*parent_group_id)(uint64_t id);
+#endif /* CONFIG_BT_OTS */
+
+	void (*playing_order)(uint8_t order);
+
+	void (*media_state)(uint8_t state);
+
+	void (*command)(struct mpl_cmd_ntf cmd_ntf);
+
+	void (*commands_supported)(uint32_t opcodes);
+
+#ifdef CONFIG_BT_OTS
+	void (*search)(uint8_t result_code);
+
+	void (*search_results_id)(uint64_t id);
+#endif /* CONFIG_BT_OTS */
+};
+
+/** @brief Register a controller with the media proxy */
+int media_proxy_sctrl_register(struct media_proxy_sctrl_cbs *sctrl_cbs);
+
+
+const char *media_proxy_sctrl_get_player_name(void);
+
+#ifdef CONFIG_BT_OTS
+uint64_t media_proxy_sctrl_get_icon_id(void);
+#endif /* CONFIG_BT_OTS */
+
+const char *media_proxy_sctrl_get_icon_url(void);
+
+
+const char *media_proxy_sctrl_get_track_title(void);
+
+int32_t media_proxy_sctrl_get_track_duration(void);
+
+int32_t media_proxy_sctrl_get_track_position(void);
+void media_proxy_sctrl_set_track_position(int32_t position);
+
+int8_t media_proxy_sctrl_get_playback_speed(void);
+void media_proxy_sctrl_set_playback_speed(int8_t speed);
+
+int8_t media_proxy_sctrl_get_seeking_speed(void);
+
+#ifdef CONFIG_BT_OTS
+uint64_t media_proxy_sctrl_get_track_segments_id(void);
+
+uint64_t media_proxy_sctrl_get_current_track_id(void);
+void media_proxy_sctrl_set_current_track_id(uint64_t id);
+
+uint64_t media_proxy_sctrl_get_next_track_id(void);
+void media_proxy_sctrl_set_next_track_id(uint64_t id);
+
+uint64_t media_proxy_sctrl_get_current_group_id(void);
+void media_proxy_sctrl_set_current_group_id(uint64_t id);
+
+uint64_t media_proxy_sctrl_get_parent_group_id(void);
+#endif /* CONFIG_BT_OTS */
+
+uint8_t media_proxy_sctrl_get_playing_order(void);
+void media_proxy_sctrl_set_playing_order(uint8_t order);
+
+uint16_t media_proxy_sctrl_get_playing_orders_supported(void);
+
+uint8_t media_proxy_sctrl_get_media_state(void);
+
+void media_proxy_sctrl_send_command(struct mpl_cmd command);
+
+uint32_t media_proxy_sctrl_get_commands_supported(void);
+
+#ifdef CONFIG_BT_OTS
+void media_proxy_sctrl_send_search(struct mpl_search search);
+
+uint64_t media_proxy_sctrl_get_search_results_id(void);
+#endif /* CONFIG_BT_OTS */
+
+uint8_t media_proxy_sctrl_get_content_ctrl_id(void);
+
+#endif /* ZEPHYR_SUBSYS_BLUETOOTH_AUDIO_MEDIA_PROXY_INTERNAL_H_ */