xref: /btstack/src/classic/avrcp_controller.c (revision c824d78c0a34df89b57d535abafcc7dacf30bb06)
1 /*
2  * Copyright (C) 2016 BlueKitchen GmbH
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the copyright holders nor the names of
14  *    contributors may be used to endorse or promote products derived
15  *    from this software without specific prior written permission.
16  * 4. Any redistribution, use, or modification is done solely for
17  *    personal benefit and not for any commercial purpose or for
18  *    monetary gain.
19  *
20  * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BLUEKITCHEN
24  * GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
27  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
30  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * Please inquire about commercial licensing options at
34  * [email protected]
35  *
36  */
37 
38 #define BTSTACK_FILE__ "avrcp_controller.c"
39 
40 #include <stdint.h>
41 #include <string.h>
42 #include <inttypes.h>
43 
44 #include "classic/avrcp.h"
45 #include "classic/avrcp_controller.h"
46 
47 #include "bluetooth_sdp.h"
48 #include "btstack_debug.h"
49 #include "btstack_event.h"
50 #include "btstack_util.h"
51 #include "l2cap.h"
52 
53 // made public in avrcp_controller.h
54 avrcp_context_t avrcp_controller_context;
55 
56 static uint8_t avrcp_controller_calc_next_transaction_label(uint8_t current_transaction_label){
57     current_transaction_label++;
58     if (current_transaction_label == 16){
59         current_transaction_label = 1;
60     }
61     return current_transaction_label;
62 }
63 
64 static uint8_t avrcp_controller_get_next_transaction_label(avrcp_connection_t * connection){
65     connection->transaction_id_counter = avrcp_controller_calc_next_transaction_label(connection->transaction_id_counter);
66     return connection->transaction_id_counter;
67 }
68 
69 static bool avrcp_controller_is_transaction_id_valid(avrcp_connection_t * connection, uint8_t transaction_id){
70     uint8_t delta = ((int8_t) transaction_id - connection->controller_last_confirmed_transaction_id) & 0x0f;
71     return delta < 15;
72 }
73 
74 static void avrcp_controller_custom_command_data_init(avrcp_connection_t * connection,
75                                                       avrcp_command_opcode_t opcode, avrcp_command_type_t command_type,
76                                                       avrcp_subunit_type_t subunit_type, avrcp_subunit_id_t subunit_id,
77                                                       avrcp_pdu_id_t pdu_id, uint32_t company_id){
78 
79     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
80     connection->command_opcode = opcode;
81     connection->command_type = command_type;
82     connection->subunit_type = subunit_type;
83     connection->subunit_id = subunit_id;
84     connection->company_id = company_id;
85     connection->pdu_id = pdu_id;
86     connection->data = NULL;
87     connection->data_offset = 0;
88     connection->data_len = 0;
89 }
90 
91 static void avrcp_controller_vendor_dependent_command_data_init(avrcp_connection_t * connection, avrcp_command_type_t command_type, avrcp_pdu_id_t pdu_id, bool get_next_transaction_label){
92     if (get_next_transaction_label){
93         connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
94     }
95     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
96     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
97     connection->subunit_id = AVRCP_SUBUNIT_ID;
98     connection->company_id = BT_SIG_COMPANY_ID;
99 
100     connection->command_type = command_type;
101     connection->pdu_id = pdu_id;
102     connection->data = connection->message_body;
103     connection->data_offset = 0;
104     connection->data_len = 0;
105 }
106 
107 static void avrcp_controller_pass_through_command_data_init(avrcp_connection_t * connection, avrcp_operation_id_t opid){
108     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
109     connection->command_opcode =  AVRCP_CMD_OPCODE_PASS_THROUGH;
110     connection->command_type = AVRCP_CTYPE_CONTROL;
111     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
112     connection->subunit_id =   AVRCP_SUBUNIT_ID;
113 
114     connection->company_id = 0;
115     connection->pdu_id = AVRCP_PDU_ID_UNDEFINED;
116     connection->operation_id = opid;
117 
118     connection->data = connection->message_body;
119     connection->data_offset = 0;
120     connection->data_len = 0;
121 }
122 
123 static int avrcp_controller_supports_browsing(uint16_t controller_supported_features){
124     return controller_supported_features & AVRCP_FEATURE_MASK_BROWSING;
125 }
126 
127 static void avrcp_controller_prepare_custom_command_response(avrcp_connection_t * connection, uint16_t response_len, uint8_t * in_place_buffer){
128     uint8_t pos = 0;
129     in_place_buffer[pos++] = HCI_EVENT_AVRCP_META;
130     // skip len
131     pos++;
132     in_place_buffer[pos++] = AVRCP_SUBEVENT_CUSTOM_COMMAND_RESPONSE;
133     little_endian_store_16(in_place_buffer, pos, connection->avrcp_cid);
134     pos += 2;
135     in_place_buffer[pos++] = (uint8_t)connection->command_type;
136     in_place_buffer[pos++] = (uint8_t)connection->pdu_id;
137     little_endian_store_16(in_place_buffer, pos, response_len);
138     pos += 2;
139     in_place_buffer[1] = pos + response_len - 2;
140 }
141 
142 static void avrcp_controller_emit_notification_complete(avrcp_connection_t * connection, uint8_t status, uint8_t event_id, bool enabled){
143     uint8_t event[8];
144     uint8_t pos = 0;
145     event[pos++] = HCI_EVENT_AVRCP_META;
146     event[pos++] = sizeof(event) - 2;
147     event[pos++] = AVRCP_SUBEVENT_NOTIFICATION_STATE;
148     little_endian_store_16(event, pos, connection->avrcp_cid);
149     pos += 2;
150     event[pos++] = status;
151     event[pos++] = enabled ? 1 : 0;
152     event[pos++] = event_id;
153     UNUSED(pos);
154     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
155 }
156 
157 static void avrcp_controller_emit_supported_events(avrcp_connection_t * connection){
158     uint8_t ctype = (uint8_t) AVRCP_CTYPE_RESPONSE_CHANGED_STABLE;
159     uint8_t event_id;
160 
161     for (event_id = (uint8_t) AVRCP_NOTIFICATION_EVENT_FIRST_INDEX; event_id < (uint8_t) AVRCP_NOTIFICATION_EVENT_LAST_INDEX; event_id++){
162         if ((connection->notifications_supported_by_target & (1 << event_id)) == 0){
163             continue;
164         }
165         uint8_t event[8];
166         uint8_t pos = 0;
167         event[pos++] = HCI_EVENT_AVRCP_META;
168         event[pos++] = sizeof(event) - 2;
169         event[pos++] = AVRCP_SUBEVENT_GET_CAPABILITY_EVENT_ID;
170         little_endian_store_16(event, pos, connection->avrcp_cid);
171         pos += 2;
172         event[pos++] = ctype;
173         event[pos++] = 0;
174         event[pos++] = event_id;
175         UNUSED(pos);
176         (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
177     }
178 
179     uint8_t event[7];
180     uint8_t pos = 0;
181     event[pos++] = HCI_EVENT_AVRCP_META;
182     event[pos++] = sizeof(event) - 2;
183     event[pos++] = AVRCP_SUBEVENT_GET_CAPABILITY_EVENT_ID_DONE;
184     little_endian_store_16(event, pos, connection->avrcp_cid);
185     pos += 2;
186     event[pos++] = ctype;
187     event[pos++] = 0;
188     UNUSED(pos);
189     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
190 }
191 
192 static void avrcp_controller_emit_notification_for_event_id(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id,
193                                                             avrcp_command_type_t ctype, const uint8_t *payload,
194                                                             uint16_t size) {
195     switch (event_id){
196         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_POS_CHANGED:{
197             if (size < 4) break;
198             uint32_t song_position = big_endian_read_32(payload, 0);
199             uint16_t offset = 0;
200             uint8_t event[10];
201             event[offset++] = HCI_EVENT_AVRCP_META;
202             event[offset++] = sizeof(event) - 2;
203             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_PLAYBACK_POS_CHANGED;
204             little_endian_store_16(event, offset, avrcp_cid);
205             offset += 2;
206             event[offset++] = ctype;
207             little_endian_store_32(event, offset, song_position);
208             offset += 4;
209             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
210             break;
211         }
212         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED:{
213             if (size < 1) break;
214             uint16_t offset = 0;
215             uint8_t event[7];
216             event[offset++] = HCI_EVENT_AVRCP_META;
217             event[offset++] = sizeof(event) - 2;
218             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_PLAYBACK_STATUS_CHANGED;
219             little_endian_store_16(event, offset, avrcp_cid);
220             offset += 2;
221             event[offset++] = ctype;
222             event[offset++] = payload[0];
223             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
224             break;
225         }
226         case AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED:{
227             uint16_t offset = 0;
228             uint8_t event[6];
229             event[offset++] = HCI_EVENT_AVRCP_META;
230             event[offset++] = sizeof(event) - 2;
231             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_TRACK_CHANGED;
232             little_endian_store_16(event, offset, avrcp_cid);
233             offset += 2;
234             event[offset++] = ctype;
235             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
236             break;
237         }
238         case AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED:{
239             uint16_t offset = 0;
240             uint8_t event[6];
241             event[offset++] = HCI_EVENT_AVRCP_META;
242             event[offset++] = sizeof(event) - 2;
243             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_NOW_PLAYING_CONTENT_CHANGED;
244             little_endian_store_16(event, offset, avrcp_cid);
245             offset += 2;
246             event[offset++] = ctype;
247             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
248             break;
249         }
250         case AVRCP_NOTIFICATION_EVENT_AVAILABLE_PLAYERS_CHANGED:{
251             uint16_t offset = 0;
252             uint8_t event[6];
253             event[offset++] = HCI_EVENT_AVRCP_META;
254             event[offset++] = sizeof(event) - 2;
255             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_AVAILABLE_PLAYERS_CHANGED;
256             little_endian_store_16(event, offset, avrcp_cid);
257             offset += 2;
258             event[offset++] = ctype;
259             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
260             break;
261         }
262         case AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED:{
263             if (size < 1) break;
264             uint16_t offset = 0;
265             uint8_t event[7];
266             event[offset++] = HCI_EVENT_AVRCP_META;
267             event[offset++] = sizeof(event) - 2;
268             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_VOLUME_CHANGED;
269             little_endian_store_16(event, offset, avrcp_cid);
270             offset += 2;
271             event[offset++] = ctype;
272             event[offset++] = payload[0] & 0x7F;
273             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
274             break;
275         }
276         case AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED:{
277             if (size < 2) break;
278             uint8_t event[8];
279             uint16_t offset = 0;
280             uint16_t uuid = big_endian_read_16(payload, 0);
281             event[offset++] = HCI_EVENT_AVRCP_META;
282             event[offset++] = sizeof(event) - 2;
283             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_UIDS_CHANGED;
284             little_endian_store_16(event, offset, avrcp_cid);
285             offset += 2;
286             event[offset++] = ctype;
287             little_endian_store_16(event, offset, uuid);
288             offset += 2;
289             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
290             break;
291         }
292 
293         case AVRCP_NOTIFICATION_EVENT_TRACK_REACHED_END:{
294             uint16_t offset = 0;
295             uint8_t event[6];
296             event[offset++] = HCI_EVENT_AVRCP_META;
297             event[offset++] = sizeof(event) - 2;
298             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_TRACK_REACHED_END;
299             little_endian_store_16(event, offset, avrcp_cid);
300             offset += 2;
301             event[offset++] = ctype;
302             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
303             break;
304         }
305         case AVRCP_NOTIFICATION_EVENT_TRACK_REACHED_START:{
306             uint16_t offset = 0;
307             uint8_t event[6];
308             event[offset++] = HCI_EVENT_AVRCP_META;
309             event[offset++] = sizeof(event) - 2;
310             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_TRACK_REACHED_START;
311             little_endian_store_16(event, offset, avrcp_cid);
312             offset += 2;
313             event[offset++] = ctype;
314             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
315             break;
316         }
317         case AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED:{
318             if (size < 1) break;
319             uint16_t offset = 0;
320             uint8_t event[7];
321             event[offset++] = HCI_EVENT_AVRCP_META;
322             event[offset++] = sizeof(event) - 2;
323             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_BATT_STATUS_CHANGED;
324             little_endian_store_16(event, offset, avrcp_cid);
325             offset += 2;
326             event[offset++] = ctype;
327             event[offset++] = payload[0];
328             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
329             break;
330         }
331 
332         case AVRCP_NOTIFICATION_EVENT_SYSTEM_STATUS_CHANGED:{
333             if (size < 1) break;
334             uint16_t offset = 0;
335             uint8_t event[7];
336             event[offset++] = HCI_EVENT_AVRCP_META;
337             event[offset++] = sizeof(event) - 2;
338             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_SYSTEM_STATUS_CHANGED;
339             little_endian_store_16(event, offset, avrcp_cid);
340             offset += 2;
341             event[offset++] = ctype;
342             event[offset++] = payload[0];
343             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
344             break;
345         }
346 
347         case AVRCP_NOTIFICATION_EVENT_PLAYER_APPLICATION_SETTING_CHANGED:
348         default:
349             log_info("avrcp: not implemented");
350             break;
351     }
352 }
353 
354 static void avrcp_controller_emit_repeat_and_shuffle_mode(btstack_packet_handler_t callback, uint16_t avrcp_cid, uint8_t ctype, avrcp_repeat_mode_t repeat_mode, avrcp_shuffle_mode_t shuffle_mode){
355     btstack_assert(callback != NULL);
356 
357     uint8_t event[8];
358     int pos = 0;
359     event[pos++] = HCI_EVENT_AVRCP_META;
360     event[pos++] = sizeof(event) - 2;
361     event[pos++] = AVRCP_SUBEVENT_SHUFFLE_AND_REPEAT_MODE;
362     little_endian_store_16(event, pos, avrcp_cid);
363     pos += 2;
364     event[pos++] = ctype;
365     event[pos++] = repeat_mode;
366     event[pos++] = shuffle_mode;
367     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
368 }
369 
370 static void avrcp_controller_emit_now_playing_info_event_done(btstack_packet_handler_t callback, uint16_t avrcp_cid, uint8_t ctype, uint8_t status){
371     uint8_t event[7];
372     int pos = 0;
373     event[pos++] = HCI_EVENT_AVRCP_META;
374     event[pos++] = sizeof(event) - 2;
375     event[pos++] = AVRCP_SUBEVENT_NOW_PLAYING_INFO_DONE;
376     little_endian_store_16(event, pos, avrcp_cid);
377     pos += 2;
378     event[pos++] = ctype;
379     event[pos++] = status;
380     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
381 }
382 
383 static void avrcp_controller_emit_now_playing_info_event(btstack_packet_handler_t callback, uint16_t avrcp_cid, uint8_t ctype, avrcp_media_attribute_id_t attr_id, uint8_t * value, uint16_t value_len){
384     uint8_t event[HCI_EVENT_BUFFER_SIZE];
385     uint16_t pos = 0;
386     event[pos++] = HCI_EVENT_AVRCP_META;
387     // reserve one byte for subevent type and data len
388 	uint16_t data_len_pos = pos;
389     pos++;
390 	uint16_t subevent_type_pos = pos;
391     pos++;
392     little_endian_store_16(event, pos, avrcp_cid);
393     pos += 2;
394     event[pos++] = ctype;
395 
396     switch (attr_id){
397         case AVRCP_MEDIA_ATTR_TITLE:
398             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TITLE_INFO;
399 			btstack_assert(value_len <= 255);
400             event[pos++] = (uint8_t) value_len;
401             (void)memcpy(event + pos, value, value_len);
402             break;
403         case AVRCP_MEDIA_ATTR_ARTIST:
404             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_ARTIST_INFO;
405 			btstack_assert(value_len <= 255);
406 			event[pos++] = (uint8_t) value_len;
407             (void)memcpy(event + pos, value, value_len);
408             break;
409         case AVRCP_MEDIA_ATTR_ALBUM:
410             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_ALBUM_INFO;
411 			btstack_assert(value_len <= 255);
412 			event[pos++] = (uint8_t) value_len;
413             (void)memcpy(event + pos, value, value_len);
414             break;
415         case AVRCP_MEDIA_ATTR_GENRE:
416             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_GENRE_INFO;
417 			btstack_assert(value_len <= 255);
418 			event[pos++] = (uint8_t) value_len;
419             (void)memcpy(event + pos, value, value_len);
420             break;
421         case AVRCP_MEDIA_ATTR_SONG_LENGTH_MS:
422             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_SONG_LENGTH_MS_INFO;
423             if (value){
424                 little_endian_store_32(event, pos, btstack_atoi((char *)value));
425             } else {
426                 little_endian_store_32(event, pos, 0);
427             }
428             pos += 4;
429             break;
430         case AVRCP_MEDIA_ATTR_TRACK:
431             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TRACK_INFO;
432             if (value){
433                 event[pos++] = btstack_atoi((char *)value);
434             } else {
435                 event[pos++] = 0;
436             }
437             break;
438         case AVRCP_MEDIA_ATTR_TOTAL_NUM_ITEMS:
439             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TOTAL_TRACKS_INFO;
440             if (value){
441                 event[pos++] = btstack_atoi((char *)value);
442             } else {
443                 event[pos++] = 0;
444             }
445             break;
446         default:
447             break;
448     }
449     event[data_len_pos] = pos - 2;
450     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
451 }
452 
453 static void avrcp_controller_emit_operation_status(btstack_packet_handler_t callback, uint8_t subevent, uint16_t avrcp_cid, uint8_t ctype, uint8_t operation_id){
454     btstack_assert(callback != NULL);
455 
456     uint8_t event[7];
457     int pos = 0;
458     event[pos++] = HCI_EVENT_AVRCP_META;
459     event[pos++] = sizeof(event) - 2;
460     event[pos++] = subevent;
461     little_endian_store_16(event, pos, avrcp_cid);
462     pos += 2;
463     event[pos++] = ctype;
464     event[pos++] = operation_id;
465     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
466 }
467 
468 static void avrcp_parser_reset(avrcp_connection_t * connection){
469     connection->list_offset = 0;
470     connection->parser_attribute_header_pos = 0;
471     connection->controller_num_received_fragments = 0;
472     connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
473 }
474 
475 static void avrcp_parser_process_byte(uint8_t byte, avrcp_connection_t * connection, avrcp_command_type_t ctype){
476     uint16_t attribute_total_value_len;
477     uint32_t attribute_id;
478     switch(connection->parser_state){
479         case AVRCP_PARSER_GET_ATTRIBUTE_HEADER:
480             connection->parser_attribute_header[connection->parser_attribute_header_pos++] = byte;
481             connection->list_offset++;
482 
483             if (connection->parser_attribute_header_pos < AVRCP_ATTRIBUTE_HEADER_LEN) return;
484 
485             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
486             connection->attribute_value_len = btstack_min(attribute_total_value_len, AVRCP_MAX_ATTRIBUTE_SIZE);
487             if (connection->attribute_value_len > 0){
488                 // get ready for attribute value
489                 connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_VALUE;
490                 return;
491             }
492 
493             // emit empty attribute
494             attribute_id = big_endian_read_32(connection->parser_attribute_header, 0);
495             avrcp_controller_emit_now_playing_info_event(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, (avrcp_media_attribute_id_t) attribute_id, connection->attribute_value, connection->attribute_value_len);
496 
497             // done, see below
498             break;
499 
500         case AVRCP_PARSER_GET_ATTRIBUTE_VALUE:
501             connection->attribute_value[connection->attribute_value_offset++] = byte;
502             connection->list_offset++;
503 
504             if (connection->attribute_value_offset < connection->attribute_value_len) return;
505 
506             // emit (potentially partial) attribute
507             attribute_id = big_endian_read_32(connection->parser_attribute_header, 0);
508             avrcp_controller_emit_now_playing_info_event(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, (avrcp_media_attribute_id_t) attribute_id, connection->attribute_value, connection->attribute_value_len);
509 
510             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
511             if (connection->attribute_value_offset < attribute_total_value_len){
512                 // ignore rest of attribute
513                 connection->parser_state = AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE;
514                 return;
515             }
516 
517             // done, see below
518             break;
519 
520         case AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE:
521             connection->attribute_value_offset++;
522             connection->list_offset++;
523 
524             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
525             if (connection->attribute_value_offset < attribute_total_value_len) return;
526 
527             // done, see below
528             break;
529 
530         default:
531             return;
532     }
533 
534     // attribute fully read, check if more to come
535     if (connection->list_offset < connection->list_size){
536         // more to come, reset parser
537         connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
538         connection->parser_attribute_header_pos = 0;
539         connection->attribute_value_offset = 0;
540     } else {
541         // fully done
542         avrcp_parser_reset(connection);
543         avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 0);
544     }
545 }
546 
547 static void avrcp_controller_parse_and_emit_element_attrs(uint8_t * packet, uint16_t num_bytes_to_read, avrcp_connection_t * connection, avrcp_command_type_t ctype){
548     int i;
549     for (i=0;i<num_bytes_to_read;i++){
550         avrcp_parser_process_byte(packet[i], connection, ctype);
551     }
552 }
553 
554 static void avrcp_send_cmd_with_avctp_fragmentation(avrcp_connection_t * connection){
555     l2cap_reserve_packet_buffer();
556     uint8_t * packet = l2cap_get_outgoing_buffer();
557 
558     uint16_t max_payload_size;
559     connection->avctp_packet_type = avctp_get_packet_type(connection, &max_payload_size);
560     connection->avrcp_packet_type = avrcp_get_packet_type(connection);
561 
562     // non-fragmented: transport header (1) + PID (2)
563     // fragmented:     transport header (1) + num packets (1) + PID (2)
564 
565     uint16_t param_len = connection->data_len;
566     // AVCTP header
567     // transport header : transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
568     uint16_t pos = 0;
569     packet[pos++] = (connection->transaction_id << 4) | (connection->avctp_packet_type << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
570 
571     if (connection->avctp_packet_type == AVCTP_START_PACKET){
572         uint16_t max_frame_size = btstack_min(connection->l2cap_mtu, AVRCP_MAX_AV_C_MESSAGE_FRAME_SIZE);
573         // first packet: max_payload_size
574         // rest packets
575         uint16_t num_payload_bytes = param_len - max_payload_size;
576         uint16_t frame_size_for_continue_packet = max_frame_size - avctp_get_num_bytes_for_header(AVCTP_CONTINUE_PACKET);
577         uint16_t num_avctp_packets = (num_payload_bytes + frame_size_for_continue_packet - 1)/frame_size_for_continue_packet + 1;
578 		btstack_assert(num_avctp_packets <= 255);
579         packet[pos++] = (uint8_t) num_avctp_packets;
580     }
581 
582     switch (connection->avctp_packet_type){
583         case AVCTP_SINGLE_PACKET:
584         case AVCTP_START_PACKET:
585             // Profile IDentifier (PID)
586             packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
587             packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
588 
589             // command_type
590             packet[pos++] = connection->command_type;
591             // subunit_type | subunit ID
592             packet[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
593             // opcode
594             packet[pos++] = (uint8_t)connection->command_opcode;
595 
596             switch (connection->command_opcode){
597                 case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
598                     big_endian_store_24(packet, pos, connection->company_id);
599                     pos += 3;
600                     packet[pos++] = connection->pdu_id;
601                     packet[pos++] = connection->avrcp_packet_type;              // reserved(upper 6) | AVRCP packet_type
602                     big_endian_store_16(packet, pos, connection->data_len);     // parameter length
603                     pos += 2;
604                     break;
605                 case AVRCP_CMD_OPCODE_PASS_THROUGH:
606                     packet[pos++] = connection->operation_id;
607                     packet[pos++] = (uint8_t)connection->data_len;     // parameter length
608                     pos += 2;
609                     break;
610                 case AVRCP_CMD_OPCODE_UNIT_INFO:
611                     break;
612                 case AVRCP_CMD_OPCODE_SUBUNIT_INFO:
613                     break;
614                 default:
615                     btstack_assert(false);
616                     return;
617             }
618             break;
619         case AVCTP_CONTINUE_PACKET:
620         case AVCTP_END_PACKET:
621             break;
622         default:
623             btstack_assert(false);
624             return;
625     }
626     // compare number of bytes to store with the remaining buffer size
627     uint16_t bytes_to_copy = btstack_min(connection->data_len - connection->data_offset, max_payload_size - pos);
628 
629     (void)memcpy(packet + pos, &connection->data[connection->data_offset], bytes_to_copy);
630     pos += bytes_to_copy;
631     connection->data_offset += bytes_to_copy;
632 
633     l2cap_send_prepared(connection->l2cap_signaling_cid, pos);
634 }
635 
636 static int avrcp_send_register_notification(avrcp_connection_t * connection, uint8_t event_id){
637     uint8_t command[18];
638     uint16_t pos = 0;
639     // transport header : transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
640     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
641     command[pos++] = (connection->transaction_id << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
642 
643     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
644     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
645     command[pos++] = AVRCP_CTYPE_NOTIFY;
646     command[pos++] = (AVRCP_SUBUNIT_TYPE_PANEL << 3) | AVRCP_SUBUNIT_ID;
647     command[pos++] = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
648 
649     big_endian_store_24(command, pos, BT_SIG_COMPANY_ID);
650     pos += 3;
651     command[pos++] = AVRCP_PDU_ID_REGISTER_NOTIFICATION;
652     command[pos++] = 0;                       // reserved(upper 6) | packet_type -> 0
653     big_endian_store_16(command, pos, 5);     // parameter length
654     pos += 2;
655     command[pos++] = event_id;
656     big_endian_store_32(command, pos, 1);     // send notification on playback position every second, for other notifications it is ignored
657     pos += 4;
658     return l2cap_send(connection->l2cap_signaling_cid, command, pos);
659 }
660 
661 static void avrcp_press_and_hold_timeout_handler(btstack_timer_source_t * timer){
662     UNUSED(timer);
663     avrcp_connection_t * connection = (avrcp_connection_t*) btstack_run_loop_get_timer_context(timer);
664     btstack_run_loop_set_timer(&connection->controller_press_and_hold_cmd_timer, 2000); // 2 seconds timeout
665     btstack_run_loop_add_timer(&connection->controller_press_and_hold_cmd_timer);
666     connection->state = AVCTP_W2_SEND_PRESS_COMMAND;
667     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
668 }
669 
670 static void avrcp_press_and_hold_timer_start(avrcp_connection_t * connection){
671     btstack_run_loop_remove_timer(&connection->controller_press_and_hold_cmd_timer);
672     btstack_run_loop_set_timer_handler(&connection->controller_press_and_hold_cmd_timer, avrcp_press_and_hold_timeout_handler);
673     btstack_run_loop_set_timer_context(&connection->controller_press_and_hold_cmd_timer, connection);
674     btstack_run_loop_set_timer(&connection->controller_press_and_hold_cmd_timer, 2000); // 2 seconds timeout
675     btstack_run_loop_add_timer(&connection->controller_press_and_hold_cmd_timer);
676 }
677 
678 static void avrcp_press_and_hold_timer_stop(avrcp_connection_t * connection){
679     connection->controller_press_and_hold_cmd_active = false;
680     btstack_run_loop_remove_timer(&connection->controller_press_and_hold_cmd_timer);
681 }
682 
683 
684 static uint8_t avrcp_controller_request_pass_through_release_control_cmd(avrcp_connection_t * connection){
685     connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
686     if (connection->controller_press_and_hold_cmd_active){
687         avrcp_press_and_hold_timer_stop(connection);
688     }
689     connection->operation_id = (avrcp_operation_id_t)(0x80 | connection->operation_id);
690     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
691     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
692     return ERROR_CODE_SUCCESS;
693 }
694 
695 static uint8_t avrcp_controller_request_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed, bool continuous_cmd){
696 	UNUSED(playback_speed);
697 
698 	log_info("Send command %d", opid);
699     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
700     if (!connection){
701         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
702     }
703 
704     if (connection->state != AVCTP_CONNECTION_OPENED){
705         log_error("Connection in wrong state %d, expected %d. avrcp cid 0x%02x", connection->state, AVCTP_CONNECTION_OPENED, avrcp_cid);
706         return ERROR_CODE_COMMAND_DISALLOWED;
707     }
708     connection->state = AVCTP_W2_SEND_PRESS_COMMAND;
709     avrcp_controller_pass_through_command_data_init(connection, opid);
710 
711     connection->controller_press_and_hold_cmd_active = continuous_cmd;
712     if (connection->controller_press_and_hold_cmd_active){
713         avrcp_press_and_hold_timer_start(connection);
714     }
715 
716     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
717     return ERROR_CODE_SUCCESS;
718 }
719 
720 static uint8_t request_single_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed){
721     return avrcp_controller_request_pass_through_press_control_cmd(avrcp_cid, opid, playback_speed, false);
722 }
723 
724 static uint8_t request_continuous_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed){
725     return avrcp_controller_request_pass_through_press_control_cmd(avrcp_cid, opid, playback_speed, true);
726 }
727 
728 static void avrcp_controller_get_capabilities_for_connection(avrcp_connection_t * connection, uint8_t capability_id){
729     connection->state = AVCTP_W2_SEND_COMMAND;
730     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_STATUS, AVRCP_PDU_ID_GET_CAPABILITIES, true);
731 
732     // Parameter Length
733     connection->data_len = 1;
734     connection->data[0] = capability_id;  // capability ID
735 
736     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
737 }
738 
739 static uint8_t avrcp_controller_register_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t event_id){
740     if ((connection->remote_capabilities_state == AVRCP_REMOTE_CAPABILITIES_KNOWN) && (connection->notifications_supported_by_target & (1 << event_id)) == 0){
741         return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
742     }
743     if ((connection->controller_notifications_to_deregister & (1 << event_id)) != 0){
744         return ERROR_CODE_COMMAND_DISALLOWED;
745     }
746     if ( (connection->notifications_enabled & (1 << event_id)) != 0){
747         return ERROR_CODE_SUCCESS;
748     }
749     connection->controller_notifications_to_register |= (1 << event_id);
750 
751     switch (connection->remote_capabilities_state){
752         case AVRCP_REMOTE_CAPABILITIES_NONE:
753             connection->remote_capabilities_state = AVRCP_REMOTE_CAPABILITIES_W4_QUERY_RESULT;
754             connection->controller_notifications_supported_by_target_suppress_emit_result = true;
755             avrcp_controller_get_capabilities_for_connection(connection, AVRCP_CAPABILITY_ID_EVENT);
756             break;
757         case AVRCP_REMOTE_CAPABILITIES_KNOWN:
758             avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
759             break;
760         default:
761             break;
762     }
763     return ERROR_CODE_SUCCESS;
764 }
765 
766 static uint8_t avrcp_controller_request_continuation(avrcp_connection_t * connection, avrcp_pdu_id_t pdu_id){
767     connection->state = AVCTP_W2_SEND_COMMAND;
768     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_CONTROL, pdu_id, false);
769 
770     // Parameter Length
771     connection->data_len = 3;
772     big_endian_store_16(connection->data, 0, 1);
773     connection->data[2] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
774 
775     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
776     return ERROR_CODE_SUCCESS;
777 }
778 
779 static uint8_t avrcp_controller_request_abort_continuation(avrcp_connection_t * connection){
780     return avrcp_controller_request_continuation(connection, AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE);
781 }
782 
783 static uint8_t avrcp_controller_request_continue_response(avrcp_connection_t * connection){
784     return avrcp_controller_request_continuation(connection, AVRCP_PDU_ID_REQUEST_CONTINUING_RESPONSE);
785 }
786 
787 static void avrcp_controller_handle_notification(avrcp_connection_t *connection, avrcp_command_type_t ctype, uint8_t *payload, uint16_t size) {
788     if (size < 1) return;
789     uint16_t pos = 0;
790     avrcp_notification_event_id_t event_id = (avrcp_notification_event_id_t) payload[pos++];
791     if ( (event_id < AVRCP_NOTIFICATION_EVENT_FIRST_INDEX) || (event_id > AVRCP_NOTIFICATION_EVENT_LAST_INDEX)){
792         return;
793     }
794 
795     uint16_t event_mask = (1 << event_id);
796     uint16_t reset_event_mask = ~event_mask;
797 
798     switch (ctype){
799         case AVRCP_CTYPE_RESPONSE_REJECTED:
800             connection->controller_notifications_to_deregister &= reset_event_mask;
801             connection->controller_notifications_to_register   &= reset_event_mask;
802             connection->controller_initial_status_reported     &= reset_event_mask;
803             avrcp_controller_emit_notification_complete(connection, ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE, event_id, false);
804             return;
805 
806         case AVRCP_CTYPE_RESPONSE_INTERIM:
807             // register as enabled
808             connection->notifications_enabled |= event_mask;
809 
810             // check if initial value is already sent
811             if ((connection->controller_initial_status_reported & event_mask) != 0 ){
812                 return;
813             }
814             // emit event only once, initially
815             avrcp_controller_emit_notification_complete(connection, ERROR_CODE_SUCCESS, event_id, true);
816             connection->controller_initial_status_reported |= event_mask;
817             // emit initial value after this switch
818             break;
819 
820         case AVRCP_CTYPE_RESPONSE_CHANGED_STABLE:
821             // received change, event is considered de-registered
822             // we are re-enabling it automatically, if it is not
823             // explicitly disabled
824             connection->notifications_enabled &= reset_event_mask;
825             if ((connection->controller_notifications_to_deregister & event_mask) == 0){
826                 avrcp_controller_register_notification(connection, event_id);
827             } else {
828                 connection->controller_notifications_to_deregister &= reset_event_mask;
829                 connection->controller_notifications_to_register   &= reset_event_mask;
830                 connection->controller_initial_status_reported     &= reset_event_mask;
831                 avrcp_controller_emit_notification_complete(connection, ERROR_CODE_SUCCESS, event_id, false);
832             }
833             break;
834 
835         default:
836             return;
837     }
838 
839     avrcp_controller_emit_notification_for_event_id(connection->avrcp_cid, event_id, ctype, payload + pos, size - pos);
840 }
841 
842 #ifdef ENABLE_AVCTP_FRAGMENTATION
843 static void avctp_reassemble_message(avrcp_connection_t * connection, avctp_packet_type_t packet_type, uint8_t *packet, uint16_t size){
844     // after header (transaction label and packet type)
845     uint16_t pos;
846     uint16_t bytes_to_store;
847 
848     switch (packet_type){
849         case AVCTP_START_PACKET:
850             if (size < 2) return;
851 
852             // store header
853             pos = 0;
854             connection->avctp_reassembly_buffer[pos] = packet[pos];
855             pos++;
856             connection->avctp_reassembly_size = pos;
857 
858             // NOTE: num packets not needed for reassembly, ignoring it does not pose security risk -> no need to store it
859             pos++;
860 
861             // PID in reassembled packet is at offset 1, it will be read later after the avctp_reassemble_message with AVCTP_END_PACKET is called
862 
863             bytes_to_store = btstack_min(size - pos, sizeof(connection->avctp_reassembly_buffer) - connection->avctp_reassembly_size);
864             memcpy(&connection->avctp_reassembly_buffer[connection->avctp_reassembly_size], &packet[pos], bytes_to_store);
865             connection->avctp_reassembly_size += bytes_to_store;
866             break;
867 
868         case AVCTP_CONTINUE_PACKET:
869         case AVCTP_END_PACKET:
870             if (size < 1) return;
871 
872             // store remaining data, ignore header
873             pos = 1;
874             bytes_to_store = btstack_min(size - pos, sizeof(connection->avctp_reassembly_buffer) - connection->avctp_reassembly_size);
875             memcpy(&connection->avctp_reassembly_buffer[connection->avctp_reassembly_size], &packet[pos], bytes_to_store);
876             connection->avctp_reassembly_size += bytes_to_store;
877             break;
878 
879         default:
880             return;
881     }
882 }
883 #endif
884 
885 static void avrcp_handle_l2cap_data_packet_for_signaling_connection(avrcp_connection_t * connection, uint8_t *packet, uint16_t size){
886     if (size < 6u) return;
887     uint8_t  pdu_id;
888     avrcp_packet_type_t  vendor_dependent_avrcp_packet_type;
889 
890     uint16_t pos = 0;
891     connection->controller_last_confirmed_transaction_id = packet[pos] >> 4;
892     avrcp_frame_type_t  frame_type =  (avrcp_frame_type_t)((packet[pos] >> 1) & 0x01);
893     avctp_packet_type_t packet_type = (avctp_packet_type_t)((packet[pos] >> 2) & 0x03);
894     pos++;
895 
896     if (frame_type != AVRCP_RESPONSE_FRAME) return;
897 
898     switch (packet_type){
899         case AVCTP_SINGLE_PACKET:
900             break;
901 
902 #ifdef ENABLE_AVCTP_FRAGMENTATION
903         case AVCTP_START_PACKET:
904         case AVCTP_CONTINUE_PACKET:
905             avctp_reassemble_message(connection, packet_type, packet, size);
906             return;
907 
908         case AVCTP_END_PACKET:
909             avctp_reassemble_message(connection, packet_type, packet, size);
910 
911             packet = connection->avctp_reassembly_buffer;
912             size   = connection->avctp_reassembly_size;
913             break;
914 #endif
915 
916         default:
917             return;
918     }
919 
920     pos += 2; // PID
921 
922     avrcp_command_type_t ctype = (avrcp_command_type_t) packet[pos++];
923 
924 #ifdef ENABLE_LOG_INFO
925     uint8_t byte_value = packet[pos];
926     avrcp_subunit_type_t subunit_type = (avrcp_subunit_type_t) (byte_value >> 3);
927     avrcp_subunit_type_t subunit_id   = (avrcp_subunit_type_t) (byte_value & 0x07);
928 #endif
929     pos++;
930 
931     uint8_t opcode = packet[pos++];
932     uint16_t param_length;
933 
934     switch (opcode){
935         case AVRCP_CMD_OPCODE_SUBUNIT_INFO:{
936             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
937             connection->state = AVCTP_CONNECTION_OPENED;
938 
939 #ifdef ENABLE_LOG_INFO
940             // page, extension code (1)
941             pos++;
942             uint8_t unit_type = packet[pos] >> 3;
943             uint8_t max_subunit_ID = packet[pos] & 0x07;
944             log_info("SUBUNIT INFO response: ctype 0x%02x (0C), subunit_type 0x%02x (1F), subunit_id 0x%02x (07), opcode 0x%02x (30), target_unit_type 0x%02x, max_subunit_ID %d", ctype, subunit_type, subunit_id, opcode, unit_type, max_subunit_ID);
945 #endif
946             break;
947         }
948         case AVRCP_CMD_OPCODE_UNIT_INFO:{
949             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
950             connection->state = AVCTP_CONNECTION_OPENED;
951 
952 #ifdef ENABLE_LOG_INFO
953             // byte value 7 (1)
954             pos++;
955             uint8_t unit_type = packet[pos] >> 3;
956             uint8_t unit = packet[pos] & 0x07;
957             pos++;
958             uint32_t company_id = big_endian_read_24(packet, pos);
959             log_info("UNIT INFO response: ctype 0x%02x (0C), subunit_type 0x%02x (1F), subunit_id 0x%02x (07), opcode 0x%02x (30), target_unit_type 0x%02x, unit %d, company_id 0x%06" PRIx32,
960                 ctype, subunit_type, subunit_id, opcode, unit_type, unit, company_id);
961 #endif
962             break;
963         }
964         case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
965             if ((size - pos) < 7){
966                 return;
967             }
968             // Company ID (3)
969             pos += 3;
970             pdu_id = packet[pos++];
971             vendor_dependent_avrcp_packet_type = (avrcp_packet_type_t)(packet[pos++] & 0x03);
972             param_length = big_endian_read_16(packet, pos);
973             pos += 2;
974 
975             if ((size - pos) < param_length) {
976                 return;
977             }
978 
979             // handle asynchronous notifications, without changing state
980             if (pdu_id == AVRCP_PDU_ID_REGISTER_NOTIFICATION){
981                 avrcp_controller_handle_notification(connection, ctype, packet + pos, size - pos);
982                 break;
983             }
984             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
985             connection->state = AVCTP_CONNECTION_OPENED;
986 
987             log_info("VENDOR DEPENDENT response: pdu id 0x%02x, param_length %d, status %s", pdu_id, param_length, avrcp_ctype2str(ctype));
988             switch (pdu_id){
989                 case AVRCP_PDU_ID_GET_CURRENT_PLAYER_APPLICATION_SETTING_VALUE:{
990                     uint8_t num_attributes = packet[pos++];
991                     int i;
992                     avrcp_repeat_mode_t  repeat_mode =  AVRCP_REPEAT_MODE_INVALID;
993                     avrcp_shuffle_mode_t shuffle_mode = AVRCP_SHUFFLE_MODE_INVALID;
994                     for (i = 0; i < num_attributes; i++){
995                         uint8_t attribute_id    = packet[pos++];
996                         uint8_t value = packet[pos++];
997                         switch (attribute_id){
998                             case 0x02:
999                                 repeat_mode = (avrcp_repeat_mode_t) value;
1000                                 break;
1001                             case 0x03:
1002                                 shuffle_mode = (avrcp_shuffle_mode_t) value;
1003                                 break;
1004                             default:
1005                                 break;
1006                         }
1007                     }
1008                     avrcp_controller_emit_repeat_and_shuffle_mode(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, repeat_mode, shuffle_mode);
1009                     break;
1010                 }
1011 
1012                 case AVRCP_PDU_ID_SET_PLAYER_APPLICATION_SETTING_VALUE:{
1013                     uint16_t offset = 0;
1014                     uint8_t event[6];
1015                     event[offset++] = HCI_EVENT_AVRCP_META;
1016                     event[offset++] = sizeof(event) - 2;
1017                     event[offset++] = AVRCP_SUBEVENT_PLAYER_APPLICATION_VALUE_RESPONSE;
1018                     little_endian_store_16(event, offset, connection->avrcp_cid);
1019                     offset += 2;
1020                     event[offset++] = ctype;
1021                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
1022                     break;
1023                 }
1024 
1025                 case AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME:{
1026                     uint16_t offset = 0;
1027                     uint8_t event[7];
1028                     event[offset++] = HCI_EVENT_AVRCP_META;
1029                     event[offset++] = sizeof(event) - 2;
1030                     event[offset++] = AVRCP_SUBEVENT_SET_ABSOLUTE_VOLUME_RESPONSE;
1031                     little_endian_store_16(event, offset, connection->avrcp_cid);
1032                     offset += 2;
1033                     event[offset++] = ctype;
1034                     event[offset++] = packet[pos++];
1035                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
1036                     break;
1037                 }
1038 
1039                 case AVRCP_PDU_ID_GET_CAPABILITIES:{
1040                     avrcp_capability_id_t capability_id = (avrcp_capability_id_t) packet[pos++];
1041                     uint8_t capability_count = 0;
1042                     if (param_length > 1){
1043                         capability_count = packet[pos++];
1044                     }
1045                     uint16_t i;
1046                     uint16_t offset = 0;
1047                     uint8_t event[10];
1048 
1049                     switch (capability_id){
1050 
1051                         case AVRCP_CAPABILITY_ID_COMPANY:
1052                             for (i = 0; (i < capability_count) && ((size - pos) >= 3); i++){
1053                                 uint32_t company_id = big_endian_read_24(packet, pos);
1054                                 pos += 3;
1055                                 log_info("  0x%06" PRIx32 ", ", company_id);
1056 
1057                                 offset = 0;
1058                                 event[offset++] = HCI_EVENT_AVRCP_META;
1059                                 event[offset++] = sizeof(event) - 2;
1060                                 event[offset++] = AVRCP_SUBEVENT_GET_CAPABILITY_COMPANY_ID;
1061                                 little_endian_store_16(event, offset, connection->avrcp_cid);
1062                                 offset += 2;
1063                                 event[offset++] = ctype;
1064                                 event[offset++] = 0;
1065                                 little_endian_store_24(event, offset, company_id);
1066                                 offset += 3;
1067                                 (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, offset);
1068                             }
1069 
1070                             offset = 0;
1071                             event[offset++] = HCI_EVENT_AVRCP_META;
1072                             event[offset++] = sizeof(event) - 2;
1073                             event[offset++] = AVRCP_SUBEVENT_GET_CAPABILITY_COMPANY_ID_DONE;
1074                             little_endian_store_16(event, offset, connection->avrcp_cid);
1075                             offset += 2;
1076                             event[offset++] = ctype;
1077                             event[offset++] = 0;
1078                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, offset);
1079                             break;
1080 
1081                         case AVRCP_CAPABILITY_ID_EVENT:
1082                             for (i = 0; (i < capability_count) && ((size - pos) >= 1); i++){
1083                                 uint8_t event_id = packet[pos++];
1084                                 connection->notifications_supported_by_target |= (1 << event_id);
1085                             }
1086 
1087                             connection->remote_capabilities_state = AVRCP_REMOTE_CAPABILITIES_KNOWN;
1088 
1089                             // if the get supported events query is triggered by avrcp_controller_enable_notification call,
1090                             // avrcp_controller_emit_supported_events should be suppressed
1091                             if (connection->controller_notifications_supported_by_target_suppress_emit_result){
1092                                 connection->controller_notifications_supported_by_target_suppress_emit_result = false;
1093                                 // also, notification might not be supported
1094                                 // if so, emit AVRCP_SUBEVENT_ENABLE_NOTIFICATION_COMPLETE event to app,
1095                                 // and update controller_notifications_to_register bitmap
1096                                 for (i = (uint8_t)AVRCP_NOTIFICATION_EVENT_FIRST_INDEX; i < (uint8_t) AVRCP_NOTIFICATION_EVENT_LAST_INDEX; i++){
1097                                     if ((connection->controller_notifications_to_register & (1 << i)) != 0){
1098                                         if ((connection->notifications_supported_by_target & (1 << i)) == 0){
1099                                             avrcp_controller_emit_notification_complete(connection, ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE, (uint8_t) i, false);
1100                                             connection->controller_notifications_to_register &= ~(1 << i);
1101                                         }
1102                                     }
1103                                 }
1104                                 break;
1105                             }
1106                             // supported events are emitted only if the get supported events query
1107                             // is triggered by avrcp_controller_get_supported_events call
1108                             avrcp_controller_emit_supported_events(connection);
1109                             break;
1110 
1111                         default:
1112                             // ignore
1113                             break;
1114                     }
1115                     break;
1116                 }
1117 
1118                 case AVRCP_PDU_ID_GET_PLAY_STATUS:{
1119                     uint32_t song_length = big_endian_read_32(packet, pos);
1120                     pos += 4;
1121                     uint32_t song_position = big_endian_read_32(packet, pos);
1122                     pos += 4;
1123                     uint8_t play_status = packet[pos];
1124 
1125                     uint8_t event[15];
1126                     int offset = 0;
1127                     event[offset++] = HCI_EVENT_AVRCP_META;
1128                     event[offset++] = sizeof(event) - 2;
1129                     event[offset++] = AVRCP_SUBEVENT_PLAY_STATUS;
1130                     little_endian_store_16(event, offset, connection->avrcp_cid);
1131                     offset += 2;
1132                     event[offset++] = ctype;
1133                     little_endian_store_32(event, offset, song_length);
1134                     offset += 4;
1135                     little_endian_store_32(event, offset, song_position);
1136                     offset += 4;
1137                     event[offset++] = play_status;
1138                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
1139                     break;
1140                 }
1141 
1142                 case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:
1143                     switch (vendor_dependent_avrcp_packet_type){
1144                         case AVRCP_START_PACKET:
1145                         case AVRCP_SINGLE_PACKET:
1146                             avrcp_parser_reset(connection);
1147                             connection->list_size = param_length;
1148                             // num_attributes
1149                             pos++;
1150 
1151                             avrcp_controller_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
1152                             if (vendor_dependent_avrcp_packet_type == AVRCP_START_PACKET){
1153                                 avrcp_controller_request_continue_response(connection);
1154                                 return;
1155                             }
1156                             break;
1157                         case AVRCP_CONTINUE_PACKET:
1158                         case AVRCP_END_PACKET:
1159                             connection->controller_num_received_fragments++;
1160 
1161                             if (connection->controller_num_received_fragments < connection->controller_max_num_fragments){
1162                                 avrcp_controller_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
1163 
1164                                 if (vendor_dependent_avrcp_packet_type == AVRCP_CONTINUE_PACKET){
1165                                     avrcp_controller_request_continue_response(connection);
1166                                     return;
1167                                 }
1168                             } else {
1169                                 avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 1);
1170                                 avrcp_parser_reset(connection);
1171                                 avrcp_controller_request_abort_continuation(connection);
1172                                 return;
1173                             }
1174                             break;
1175                         default:
1176                             btstack_assert(false);
1177                             break;
1178                     }
1179                     break;
1180 
1181                 default:
1182                     // custom command response comes here
1183                     switch (pdu_id){
1184                         case AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE:
1185                             avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 0);
1186                             break;
1187                         default:
1188                             if (pdu_id != connection->pdu_id) {
1189                                 break;
1190                             }
1191                             uint8_t *in_place_buffer = packet + pos - 9;
1192                             avrcp_controller_prepare_custom_command_response(connection, param_length,
1193                                                                              in_place_buffer);
1194                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, in_place_buffer,
1195                                                                        param_length + 9);
1196 
1197                             break;
1198                     }
1199                     break;
1200             }
1201             break;
1202         case AVRCP_CMD_OPCODE_PASS_THROUGH:{
1203             if ((size - pos) < 1) return;
1204             uint8_t operation_id = packet[pos++];
1205             switch (connection->state){
1206                 case AVCTP_W2_RECEIVE_PRESS_RESPONSE:
1207                     // trigger release for simple command:
1208                     if (!connection->controller_press_and_hold_cmd_active){
1209                         connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
1210                         break;
1211                     }
1212                     // for press and hold, send release if it just has been requested, otherwise, wait for next repeat
1213                     if (connection->controller_press_and_hold_cmd_release){
1214                         connection->controller_press_and_hold_cmd_release = false;
1215                         connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
1216                     } else {
1217                         connection->state = AVCTP_W4_STOP;
1218                     }
1219                     break;
1220                 case AVCTP_W2_RECEIVE_RESPONSE:
1221                     connection->state = AVCTP_CONNECTION_OPENED;
1222                     break;
1223                 default:
1224                     break;
1225             }
1226             if (connection->state == AVCTP_W4_STOP){
1227                 avrcp_controller_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_START, connection->avrcp_cid, ctype, operation_id);
1228             }
1229             if (connection->state == AVCTP_CONNECTION_OPENED) {
1230                 // RELEASE response
1231                 operation_id = operation_id & 0x7F;
1232                 avrcp_controller_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_COMPLETE, connection->avrcp_cid, ctype, operation_id);
1233             }
1234             if (connection->state == AVCTP_W2_SEND_RELEASE_COMMAND){
1235                 // PRESS response
1236                 avrcp_controller_request_pass_through_release_control_cmd(connection);
1237             }
1238             break;
1239         }
1240         default:
1241             break;
1242     }
1243 
1244     // trigger pending notification reqistrations
1245     if ((connection->state == AVCTP_CONNECTION_OPENED) && connection->controller_notifications_to_register){
1246         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1247     }
1248 }
1249 
1250 static void avrcp_controller_handle_can_send_now(avrcp_connection_t * connection){
1251     switch (connection->state){
1252         case AVCTP_W2_SEND_PRESS_COMMAND:
1253             avrcp_send_cmd_with_avctp_fragmentation(connection);
1254             connection->state = AVCTP_W2_RECEIVE_PRESS_RESPONSE;
1255             break;
1256 
1257         case AVCTP_W2_SEND_RELEASE_COMMAND:
1258             avrcp_send_cmd_with_avctp_fragmentation(connection);
1259             connection->state = AVCTP_W2_RECEIVE_RESPONSE;
1260             break;
1261 
1262         case AVCTP_W2_SEND_COMMAND:
1263             avrcp_send_cmd_with_avctp_fragmentation(connection);
1264             if (connection->data_offset < connection->data_len){
1265                 // continue AVCTP fragmentation
1266                 avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1267                 return;
1268             }
1269             connection->state = AVCTP_W2_RECEIVE_RESPONSE;
1270             return;
1271         default:
1272             break;
1273     }
1274 
1275     // send register notification if queued
1276     if (connection->controller_notifications_to_register != 0){
1277         uint8_t event_id;
1278         for (event_id = (uint8_t)AVRCP_NOTIFICATION_EVENT_FIRST_INDEX; event_id < (uint8_t)AVRCP_NOTIFICATION_EVENT_LAST_INDEX; event_id++){
1279             if (connection->controller_notifications_to_register & (1 << event_id)){
1280                 connection->controller_notifications_to_register &= ~ (1 << event_id);
1281                 avrcp_send_register_notification(connection, event_id);
1282                 return;
1283             }
1284         }
1285     }
1286 }
1287 
1288 static void avrcp_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
1289     avrcp_connection_t * connection;
1290 
1291     switch (packet_type) {
1292         case L2CAP_DATA_PACKET:
1293             connection = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, channel);
1294             avrcp_handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
1295             break;
1296 
1297         case HCI_EVENT_PACKET:
1298             switch (hci_event_packet_get_type(packet)){
1299                 case L2CAP_EVENT_CAN_SEND_NOW:
1300                     connection = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, channel);
1301                     avrcp_controller_handle_can_send_now(connection);
1302                     break;
1303             default:
1304                 break;
1305         }
1306         default:
1307             break;
1308     }
1309 }
1310 
1311 void avrcp_controller_create_sdp_record(uint8_t * service, uint32_t service_record_handle, uint16_t supported_features, const char * service_name, const char * service_provider_name){
1312     avrcp_create_sdp_record(1, service, service_record_handle, avrcp_controller_supports_browsing(supported_features), supported_features, service_name, service_provider_name);
1313 }
1314 
1315 void avrcp_controller_init(void){
1316     avrcp_controller_context.role = AVRCP_CONTROLLER;
1317     avrcp_controller_context.packet_handler = avrcp_controller_packet_handler;
1318     avrcp_register_controller_packet_handler(&avrcp_controller_packet_handler);
1319 }
1320 
1321 void avrcp_controller_deinit(void){
1322     memset(&avrcp_controller_context, 0, sizeof(avrcp_context_t));
1323 }
1324 
1325 void avrcp_controller_register_packet_handler(btstack_packet_handler_t callback){
1326     btstack_assert(callback != NULL);
1327     avrcp_controller_context.avrcp_callback = callback;
1328 }
1329 
1330 
1331 uint8_t avrcp_controller_play(uint16_t avrcp_cid){
1332     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PLAY, 0);
1333 }
1334 
1335 uint8_t avrcp_controller_stop(uint16_t avrcp_cid){
1336     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_STOP, 0);
1337 }
1338 
1339 uint8_t avrcp_controller_pause(uint16_t avrcp_cid){
1340     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PAUSE, 0);
1341 }
1342 
1343 uint8_t avrcp_controller_forward(uint16_t avrcp_cid){
1344     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FORWARD, 0);
1345 }
1346 
1347 uint8_t avrcp_controller_backward(uint16_t avrcp_cid){
1348     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_BACKWARD, 0);
1349 }
1350 
1351 uint8_t avrcp_controller_volume_up(uint16_t avrcp_cid){
1352     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_UP, 0);
1353 }
1354 
1355 uint8_t avrcp_controller_volume_down(uint16_t avrcp_cid){
1356     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_DOWN, 0);
1357 }
1358 
1359 uint8_t avrcp_controller_mute(uint16_t avrcp_cid){
1360     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_MUTE, 0);
1361 }
1362 
1363 uint8_t avrcp_controller_skip(uint16_t avrcp_cid){
1364     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_SKIP, 0);
1365 }
1366 
1367 uint8_t avrcp_controller_fast_forward(uint16_t avrcp_cid){
1368     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1369 }
1370 
1371 uint8_t avrcp_controller_rewind(uint16_t avrcp_cid){
1372     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
1373 }
1374 
1375 /* start continuous cmds */
1376 
1377 uint8_t avrcp_controller_start_press_and_hold_cmd(uint16_t avrcp_cid, avrcp_operation_id_t operation_id){
1378     return request_continuous_pass_through_press_control_cmd(avrcp_cid, operation_id, 0);
1379 }
1380 
1381 uint8_t avrcp_controller_press_and_hold_play(uint16_t avrcp_cid){
1382     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PLAY, 0);
1383 }
1384 uint8_t avrcp_controller_press_and_hold_stop(uint16_t avrcp_cid){
1385     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_STOP, 0);
1386 }
1387 uint8_t avrcp_controller_press_and_hold_pause(uint16_t avrcp_cid){
1388     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PAUSE, 0);
1389 }
1390 uint8_t avrcp_controller_press_and_hold_forward(uint16_t avrcp_cid){
1391     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FORWARD, 0);
1392 }
1393 uint8_t avrcp_controller_press_and_hold_backward(uint16_t avrcp_cid){
1394     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_BACKWARD, 0);
1395 }
1396 uint8_t avrcp_controller_press_and_hold_fast_forward(uint16_t avrcp_cid){
1397     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1398 }
1399 uint8_t avrcp_controller_press_and_hold_rewind(uint16_t avrcp_cid){
1400     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
1401 }
1402 uint8_t avrcp_controller_press_and_hold_volume_up(uint16_t avrcp_cid){
1403     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_UP, 0);
1404 }
1405 uint8_t avrcp_controller_press_and_hold_volume_down(uint16_t avrcp_cid){
1406     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_DOWN, 0);
1407 }
1408 uint8_t avrcp_controller_press_and_hold_mute(uint16_t avrcp_cid){
1409     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_MUTE, 0);
1410 }
1411 
1412 /* stop continuous cmds */
1413 uint8_t avrcp_controller_release_press_and_hold_cmd(uint16_t avrcp_cid){
1414     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1415     if (!connection){
1416         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1417     }
1418 
1419     switch (connection->state){
1420         // respond when we receive response for (repeated) press command
1421         case AVCTP_W2_RECEIVE_PRESS_RESPONSE:
1422             connection->controller_press_and_hold_cmd_release = true;
1423             break;
1424 
1425         // release already sent or on the way, nothing to do
1426         case AVCTP_W2_RECEIVE_RESPONSE:
1427         case AVCTP_W2_SEND_RELEASE_COMMAND:
1428             break;
1429 
1430         // about to send next repeated press command or wait for it -> release right away
1431         case AVCTP_W2_SEND_PRESS_COMMAND:
1432         case AVCTP_W4_STOP:
1433             return avrcp_controller_request_pass_through_release_control_cmd(connection);
1434 
1435         // otherwise reject request
1436         default:
1437             return ERROR_CODE_COMMAND_DISALLOWED;
1438     }
1439     return ERROR_CODE_SUCCESS;
1440 }
1441 
1442 uint8_t avrcp_controller_enable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1443     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1444     if (!connection){
1445         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1446     }
1447     return avrcp_controller_register_notification(connection, event_id);
1448 }
1449 
1450 uint8_t avrcp_controller_disable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1451     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1452     if (!connection){
1453         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1454     }
1455     if (connection->remote_capabilities_state != AVRCP_REMOTE_CAPABILITIES_KNOWN){
1456         return ERROR_CODE_COMMAND_DISALLOWED;
1457     }
1458 
1459     if ((connection->notifications_supported_by_target & (1 << event_id)) == 0){
1460         return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1461     }
1462 
1463     if ((connection->notifications_enabled & (1 << event_id)) == 0){
1464         return ERROR_CODE_SUCCESS;
1465     }
1466 
1467     connection->controller_notifications_to_deregister |= (1 << event_id);
1468     return ERROR_CODE_SUCCESS;
1469 }
1470 
1471 uint8_t avrcp_controller_unit_info(uint16_t avrcp_cid){
1472     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1473     if (!connection){
1474         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1475     }
1476     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1477 
1478     connection->state = AVCTP_W2_SEND_COMMAND;
1479     avrcp_controller_custom_command_data_init(connection, AVRCP_CMD_OPCODE_UNIT_INFO, AVRCP_CTYPE_STATUS,
1480                                               AVRCP_SUBUNIT_TYPE_UNIT, AVRCP_SUBUNIT_ID_IGNORE, AVRCP_PDU_ID_UNDEFINED,
1481                                               0);
1482 
1483     connection->data = connection->message_body;
1484     memset(connection->data, 0xFF, 5);
1485     connection->data_len = 5;
1486     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1487     return ERROR_CODE_SUCCESS;
1488 }
1489 
1490 uint8_t avrcp_controller_subunit_info(uint16_t avrcp_cid){
1491     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1492     if (!connection){
1493         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1494     }
1495     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1496 
1497     connection->state = AVCTP_W2_SEND_COMMAND;
1498     avrcp_controller_custom_command_data_init(connection, AVRCP_CMD_OPCODE_SUBUNIT_INFO, AVRCP_CTYPE_STATUS,
1499                                               AVRCP_SUBUNIT_TYPE_UNIT, AVRCP_SUBUNIT_ID_IGNORE, AVRCP_PDU_ID_UNDEFINED,
1500                                               0);
1501 
1502     connection->data = connection->message_body;
1503     memset(connection->data, 0xFF, 5);
1504     connection->data[0] = 7; // page: 0, extension_code: 7
1505     connection->data_len = 5;
1506     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1507     return ERROR_CODE_SUCCESS;
1508 }
1509 
1510 uint8_t avrcp_controller_get_supported_company_ids(uint16_t avrcp_cid){
1511     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1512     if (!connection){
1513         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1514     }
1515     if (connection->state != AVCTP_CONNECTION_OPENED){
1516         return ERROR_CODE_COMMAND_DISALLOWED;
1517     }
1518     avrcp_controller_get_capabilities_for_connection(connection, AVRCP_CAPABILITY_ID_COMPANY);
1519     return ERROR_CODE_SUCCESS;
1520 }
1521 
1522 uint8_t avrcp_controller_get_supported_events(uint16_t avrcp_cid){
1523     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1524     if (!connection){
1525         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1526     }
1527     if (connection->state != AVCTP_CONNECTION_OPENED){
1528         return ERROR_CODE_COMMAND_DISALLOWED;
1529     }
1530 
1531     switch (connection->remote_capabilities_state){
1532         case AVRCP_REMOTE_CAPABILITIES_NONE:
1533             connection->remote_capabilities_state = AVRCP_REMOTE_CAPABILITIES_W4_QUERY_RESULT;
1534             avrcp_controller_get_capabilities_for_connection(connection, AVRCP_CAPABILITY_ID_EVENT);
1535             break;
1536         case AVRCP_REMOTE_CAPABILITIES_KNOWN:
1537             avrcp_controller_emit_supported_events(connection);
1538             break;
1539         default:
1540             break;
1541     }
1542     return ERROR_CODE_SUCCESS;
1543 }
1544 
1545 uint8_t avrcp_controller_get_play_status(uint16_t avrcp_cid){
1546     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1547     if (!connection){
1548         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1549     }
1550     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1551 
1552     connection->state = AVCTP_W2_SEND_COMMAND;
1553     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_STATUS, AVRCP_PDU_ID_GET_PLAY_STATUS, true);
1554 
1555     connection->data_len = 0;
1556     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1557     return ERROR_CODE_SUCCESS;
1558 }
1559 
1560 uint8_t avrcp_controller_set_addressed_player(uint16_t avrcp_cid, uint16_t addressed_player_id){
1561     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1562     if (!connection){
1563         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1564     }
1565     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1566 
1567     connection->state = AVCTP_W2_SEND_COMMAND;
1568     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_CONTROL, AVRCP_PDU_ID_SET_ADDRESSED_PLAYER, true);
1569 
1570     connection->data_len = 2;
1571     big_endian_store_16(connection->data, 0, addressed_player_id);
1572 
1573     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1574     return ERROR_CODE_SUCCESS;
1575 }
1576 
1577 uint8_t avrcp_controller_get_element_attributes(uint16_t avrcp_cid, uint8_t num_attributes, avrcp_media_attribute_id_t * attributes){
1578     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1579     if (!connection){
1580         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1581     }
1582 
1583     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1584 
1585     if (num_attributes >= AVRCP_MEDIA_ATTR_RESERVED) {
1586         return ERROR_CODE_INVALID_HCI_COMMAND_PARAMETERS;
1587     }
1588 
1589     connection->state = AVCTP_W2_SEND_COMMAND;
1590     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_STATUS, AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES, true);
1591 
1592     uint8_t pos = 0;
1593     // write 8 bytes value
1594     memset(connection->data, pos, 8); // identifier: PLAYING
1595     pos += 8;
1596 
1597     uint8_t num_attributes_index = pos;
1598     pos++;
1599 
1600     // If num_attributes is set to zero, all attribute information shall be returned,
1601     // and the AttributeID field is omitted
1602     connection->data[num_attributes_index] = 0;
1603     uint8_t i;
1604     for (i = 0; i < num_attributes; i++){
1605         // ignore invalid attribute ID and "get all attributes"
1606         if (AVRCP_MEDIA_ATTR_ALL < attributes[i] && attributes[i] < AVRCP_MEDIA_ATTR_RESERVED){
1607             // every attribute is 4 bytes long
1608             big_endian_store_32(connection->data, pos, attributes[i]);
1609             pos += 4;
1610             connection->data[num_attributes_index]++;
1611         }
1612     }
1613 
1614     // Parameter Length
1615     connection->data_len = pos;
1616 
1617     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1618     return ERROR_CODE_SUCCESS;
1619 }
1620 
1621 uint8_t avrcp_controller_get_now_playing_info(uint16_t avrcp_cid){
1622     return avrcp_controller_get_element_attributes(avrcp_cid, 0, NULL);
1623 }
1624 
1625 uint8_t avrcp_controller_get_now_playing_info_for_media_attribute_id(uint16_t avrcp_cid, avrcp_media_attribute_id_t media_attribute_id){
1626     if (media_attribute_id == AVRCP_MEDIA_ATTR_ALL){
1627         return avrcp_controller_get_now_playing_info(avrcp_cid);
1628     }
1629     avrcp_media_attribute_id_t media_attrs[1];
1630     media_attrs[0] = media_attribute_id;
1631     return avrcp_controller_get_element_attributes(avrcp_cid, 1, media_attrs);
1632 }
1633 
1634 uint8_t avrcp_controller_set_absolute_volume(uint16_t avrcp_cid, uint8_t volume){
1635      avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1636     if (!connection){
1637         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1638     }
1639 
1640     //
1641     // allow sending of multiple set abs volume commands without waiting for response
1642     //
1643     uint8_t status = ERROR_CODE_COMMAND_DISALLOWED;
1644     switch (connection->state){
1645         case AVCTP_CONNECTION_OPENED:
1646             status = ERROR_CODE_SUCCESS;
1647             break;
1648         case AVCTP_W2_RECEIVE_RESPONSE:
1649             // - is pending response also set abs volume
1650             if (connection->command_opcode  != AVRCP_CMD_OPCODE_VENDOR_DEPENDENT) break;
1651             if (connection->command_type    != AVRCP_CTYPE_CONTROL)               break;
1652             if (connection->subunit_type    != AVRCP_SUBUNIT_TYPE_PANEL)          break;
1653             if (connection->subunit_id      != AVRCP_SUBUNIT_ID)                  break;
1654             if (connection->pdu_id          != AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME)  break;
1655             // - is next transaction id valid in window
1656             if (avrcp_controller_is_transaction_id_valid(connection, avrcp_controller_calc_next_transaction_label(connection->transaction_id_counter)) == false) break;
1657             status = ERROR_CODE_SUCCESS;
1658             break;
1659         default:
1660             break;
1661     }
1662     if (status != ERROR_CODE_SUCCESS) return status;
1663 
1664     connection->state = AVCTP_W2_SEND_COMMAND;
1665     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_CONTROL, AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME, true);
1666 
1667     // Parameter Length
1668     connection->data_len = 1;
1669     connection->data[0] = volume;
1670 
1671     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1672     return ERROR_CODE_SUCCESS;
1673 }
1674 
1675 uint8_t avrcp_controller_query_shuffle_and_repeat_modes(uint16_t avrcp_cid){
1676     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1677     if (!connection){
1678         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1679     }
1680     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1681 
1682     connection->state = AVCTP_W2_SEND_COMMAND;
1683     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_STATUS, AVRCP_PDU_ID_GET_CURRENT_PLAYER_APPLICATION_SETTING_VALUE, true);
1684 
1685     connection->data_len = 5;
1686     connection->data[0] = 4;                     // NumPlayerApplicationSettingAttributeID
1687     // PlayerApplicationSettingAttributeID1 AVRCP Spec, Appendix F, 133
1688     connection->data[1] = 0x01;   // equalizer  (1-OFF, 2-ON)
1689     connection->data[2] = 0x02;   // repeat     (1-off, 2-single track, 3-all tracks, 4-group repeat)
1690     connection->data[3] = 0x03;   // shuffle    (1-off, 2-all tracks, 3-group shuffle)
1691     connection->data[4] = 0x04;   // scan       (1-off, 2-all tracks, 3-group scan)
1692 
1693     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1694     return ERROR_CODE_SUCCESS;
1695 }
1696 
1697 static uint8_t avrcp_controller_set_current_player_application_setting_value(uint16_t avrcp_cid, uint8_t attr_id, uint8_t attr_value){
1698     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1699     if (!connection){
1700         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1701     }
1702     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1703 
1704     connection->state = AVCTP_W2_SEND_COMMAND;
1705     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_CONTROL, AVRCP_PDU_ID_SET_PLAYER_APPLICATION_SETTING_VALUE, true);
1706 
1707     // Parameter Length
1708     connection->data_len = 3;
1709     connection->data[0]  = 2;
1710     connection->data[1]  = attr_id;
1711     connection->data[2]  = attr_value;
1712 
1713     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1714     return ERROR_CODE_SUCCESS;
1715 }
1716 
1717 uint8_t avrcp_controller_set_shuffle_mode(uint16_t avrcp_cid, avrcp_shuffle_mode_t mode){
1718     if ((mode < AVRCP_SHUFFLE_MODE_OFF) || (mode > AVRCP_SHUFFLE_MODE_GROUP)) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1719     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x03, mode);
1720 }
1721 
1722 uint8_t avrcp_controller_set_repeat_mode(uint16_t avrcp_cid, avrcp_repeat_mode_t mode){
1723     if ((mode < AVRCP_REPEAT_MODE_OFF) || (mode > AVRCP_REPEAT_MODE_GROUP)) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1724     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x02, mode);
1725 }
1726 
1727 uint8_t avrcp_controller_play_item_for_scope(uint16_t avrcp_cid, uint8_t * uid, uint16_t uid_counter, avrcp_browsing_scope_t scope){
1728     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1729     if (!connection){
1730         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1731     }
1732     if (connection->state != AVCTP_CONNECTION_OPENED){
1733         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1734         return ERROR_CODE_COMMAND_DISALLOWED;
1735     }
1736     connection->state = AVCTP_W2_SEND_COMMAND;
1737     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_CONTROL, AVRCP_PDU_ID_PLAY_ITEM, true);
1738 
1739     // Parameter Length
1740     connection->data_len = 11;
1741     connection->data[0]  = scope;
1742     memset(&connection->data[1], 0, 8);
1743     if (uid){
1744         (void)memcpy(&connection->data[1], uid, 8);
1745     }
1746     big_endian_store_16(connection->data, 9, uid_counter);
1747 
1748     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1749     return ERROR_CODE_SUCCESS;
1750 }
1751 
1752 uint8_t avrcp_controller_add_item_from_scope_to_now_playing_list(uint16_t avrcp_cid, uint8_t * uid, uint16_t uid_counter, avrcp_browsing_scope_t scope){
1753     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1754     if (!connection){
1755         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1756     }
1757     if (connection->state != AVCTP_CONNECTION_OPENED){
1758         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1759         return ERROR_CODE_COMMAND_DISALLOWED;
1760     }
1761 
1762     connection->state = AVCTP_W2_SEND_COMMAND;
1763     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_CONTROL, AVRCP_PDU_ID_ADD_TO_NOW_PLAYING, true);
1764 
1765     // Parameter Length
1766     connection->data_len = 11;
1767     connection->data[0]  = scope;
1768     memset(&connection->data[1], 0, 8);
1769     if (uid){
1770         (void)memcpy(&connection->data[1], uid, 8);
1771     }
1772     big_endian_store_16(connection->data, 9, uid_counter);
1773 
1774     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1775     return ERROR_CODE_SUCCESS;
1776 }
1777 
1778 uint8_t avrcp_controller_set_max_num_fragments(uint16_t avrcp_cid, uint8_t max_num_fragments){
1779     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1780     if (!connection){
1781         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1782     }
1783     connection->controller_max_num_fragments = max_num_fragments;
1784     return ERROR_CODE_SUCCESS;
1785 }
1786 
1787 
1788 uint8_t avrcp_controller_send_custom_command(uint16_t avrcp_cid,
1789     avrcp_command_type_t command_type,
1790     avrcp_subunit_type_t subunit_type, avrcp_subunit_id_t subunit_id,
1791     avrcp_pdu_id_t pdu_id, uint32_t company_id,
1792     const uint8_t * data, uint16_t data_len){
1793 
1794     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1795     if (!connection){
1796         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1797     }
1798     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1799 
1800     connection->state = AVCTP_W2_SEND_COMMAND;
1801     avrcp_controller_custom_command_data_init(connection, AVRCP_CMD_OPCODE_VENDOR_DEPENDENT, command_type, subunit_type,
1802                                               subunit_id, pdu_id, company_id);
1803 
1804     connection->data = (uint8_t *)data;
1805     connection->data_len = data_len;
1806 
1807     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1808     return ERROR_CODE_SUCCESS;
1809 }
1810 
1811 uint8_t avrcp_controller_force_send_press_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid){
1812     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1813     if (!connection){
1814         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1815     }
1816     if (connection->state < AVCTP_CONNECTION_OPENED){
1817         return ERROR_CODE_COMMAND_DISALLOWED;
1818     }
1819 
1820     connection->state = AVCTP_W2_SEND_COMMAND;
1821     avrcp_controller_pass_through_command_data_init(connection, opid);
1822     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1823     return ERROR_CODE_SUCCESS;
1824 }