xref: /btstack/src/classic/avrcp_controller.c (revision ccfcd81e62b29377c582b532cdd618dcb7ae5c21)
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->last_confirmed_transaction_id) & 0x0f;
71     return delta < 15;
72 }
73 
74 static void avrcp_controller_custome_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){
92     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
93     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
94     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
95     connection->subunit_id = AVRCP_SUBUNIT_ID;
96     connection->company_id = BT_SIG_COMPANY_ID;
97 
98     connection->command_type = command_type;
99     connection->pdu_id = pdu_id;
100     connection->data = connection->cmd_operands;
101     connection->data_offset = 0;
102     connection->data_len = 0;
103 }
104 
105 static void avrcp_controller_pass_through_command_data_init(avrcp_connection_t * connection, avrcp_operation_id_t opid){
106     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
107     connection->command_opcode =  AVRCP_CMD_OPCODE_PASS_THROUGH;
108     connection->command_type = AVRCP_CTYPE_CONTROL;
109     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
110     connection->subunit_id =   AVRCP_SUBUNIT_ID;
111 
112     connection->company_id = 0;
113     connection->pdu_id = 0;
114     connection->operation_id = opid;
115 
116     connection->data = connection->cmd_operands;
117     connection->data_offset = 0;
118     connection->data_len = 0;
119 }
120 static int avrcp_controller_supports_browsing(uint16_t controller_supported_features){
121     return controller_supported_features & AVRCP_FEATURE_MASK_BROWSING;
122 }
123 
124 static void avrcp_controller_emit_notification_complete(avrcp_connection_t * connection, uint8_t status, uint8_t event_id, bool enabled){
125     uint8_t event[8];
126     uint8_t pos = 0;
127     event[pos++] = HCI_EVENT_AVRCP_META;
128     event[pos++] = sizeof(event) - 2;
129     event[pos++] = AVRCP_SUBEVENT_NOTIFICATION_STATE;
130     little_endian_store_16(event, pos, connection->avrcp_cid);
131     pos += 2;
132     event[pos++] = status;
133     event[pos++] = enabled ? 1 : 0;
134     event[pos++] = event_id;
135     UNUSED(pos);
136     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
137 }
138 
139 static void avrcp_controller_emit_supported_events(avrcp_connection_t * connection){
140     uint8_t ctype = (uint8_t) AVRCP_CTYPE_RESPONSE_CHANGED_STABLE;
141     uint8_t event_id;
142 
143     for (event_id = (uint8_t) AVRCP_NOTIFICATION_EVENT_FIRST_INDEX; event_id < (uint8_t) AVRCP_NOTIFICATION_EVENT_LAST_INDEX; event_id++){
144         if ( (connection->target_supported_notifications & (1<<event_id)) == 0){
145             continue;
146         }
147         uint8_t event[8];
148         uint8_t pos = 0;
149         event[pos++] = HCI_EVENT_AVRCP_META;
150         event[pos++] = sizeof(event) - 2;
151         event[pos++] = AVRCP_SUBEVENT_GET_CAPABILITY_EVENT_ID;
152         little_endian_store_16(event, pos, connection->avrcp_cid);
153         pos += 2;
154         event[pos++] = ctype;
155         event[pos++] = 0;
156         event[pos++] = event_id;
157         UNUSED(pos);
158         (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
159     }
160 
161     uint8_t event[7];
162     uint8_t pos = 0;
163     event[pos++] = HCI_EVENT_AVRCP_META;
164     event[pos++] = sizeof(event) - 2;
165     event[pos++] = AVRCP_SUBEVENT_GET_CAPABILITY_EVENT_ID_DONE;
166     little_endian_store_16(event, pos, connection->avrcp_cid);
167     pos += 2;
168     event[pos++] = ctype;
169     event[pos++] = 0;
170     UNUSED(pos);
171     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
172 }
173 
174 static void avrcp_controller_emit_notification_for_event_id(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id,
175                                                             avrcp_command_type_t ctype, const uint8_t *payload,
176                                                             uint16_t size) {
177     switch (event_id){
178         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_POS_CHANGED:{
179             if (size < 4) break;
180             uint32_t song_position = big_endian_read_32(payload, 0);
181             uint16_t offset = 0;
182             uint8_t event[10];
183             event[offset++] = HCI_EVENT_AVRCP_META;
184             event[offset++] = sizeof(event) - 2;
185             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_PLAYBACK_POS_CHANGED;
186             little_endian_store_16(event, offset, avrcp_cid);
187             offset += 2;
188             event[offset++] = ctype;
189             little_endian_store_32(event, offset, song_position);
190             offset += 4;
191             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
192             break;
193         }
194         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED:{
195             if (size < 1) break;
196             uint16_t offset = 0;
197             uint8_t event[7];
198             event[offset++] = HCI_EVENT_AVRCP_META;
199             event[offset++] = sizeof(event) - 2;
200             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_PLAYBACK_STATUS_CHANGED;
201             little_endian_store_16(event, offset, avrcp_cid);
202             offset += 2;
203             event[offset++] = ctype;
204             event[offset++] = payload[0];
205             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
206             break;
207         }
208         case AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED:{
209             uint16_t offset = 0;
210             uint8_t event[6];
211             event[offset++] = HCI_EVENT_AVRCP_META;
212             event[offset++] = sizeof(event) - 2;
213             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_TRACK_CHANGED;
214             little_endian_store_16(event, offset, avrcp_cid);
215             offset += 2;
216             event[offset++] = ctype;
217             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
218             break;
219         }
220         case AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED:{
221             uint16_t offset = 0;
222             uint8_t event[6];
223             event[offset++] = HCI_EVENT_AVRCP_META;
224             event[offset++] = sizeof(event) - 2;
225             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_NOW_PLAYING_CONTENT_CHANGED;
226             little_endian_store_16(event, offset, avrcp_cid);
227             offset += 2;
228             event[offset++] = ctype;
229             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
230             break;
231         }
232         case AVRCP_NOTIFICATION_EVENT_AVAILABLE_PLAYERS_CHANGED:{
233             uint16_t offset = 0;
234             uint8_t event[6];
235             event[offset++] = HCI_EVENT_AVRCP_META;
236             event[offset++] = sizeof(event) - 2;
237             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_AVAILABLE_PLAYERS_CHANGED;
238             little_endian_store_16(event, offset, avrcp_cid);
239             offset += 2;
240             event[offset++] = ctype;
241             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
242             break;
243         }
244         case AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED:{
245             if (size < 1) break;
246             uint16_t offset = 0;
247             uint8_t event[7];
248             event[offset++] = HCI_EVENT_AVRCP_META;
249             event[offset++] = sizeof(event) - 2;
250             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_VOLUME_CHANGED;
251             little_endian_store_16(event, offset, avrcp_cid);
252             offset += 2;
253             event[offset++] = ctype;
254             event[offset++] = payload[0] & 0x7F;
255             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
256             break;
257         }
258         case AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED:{
259             if (size < 2) break;
260             uint8_t event[8];
261             uint16_t offset = 0;
262             uint16_t uuid = big_endian_read_16(payload, 0);
263             event[offset++] = HCI_EVENT_AVRCP_META;
264             event[offset++] = sizeof(event) - 2;
265             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_UIDS_CHANGED;
266             little_endian_store_16(event, offset, avrcp_cid);
267             offset += 2;
268             event[offset++] = ctype;
269             little_endian_store_16(event, offset, uuid);
270             offset += 2;
271             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
272             break;
273         }
274 
275         case AVRCP_NOTIFICATION_EVENT_TRACK_REACHED_END:{
276             uint16_t offset = 0;
277             uint8_t event[6];
278             event[offset++] = HCI_EVENT_AVRCP_META;
279             event[offset++] = sizeof(event) - 2;
280             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_TRACK_REACHED_END;
281             little_endian_store_16(event, offset, avrcp_cid);
282             offset += 2;
283             event[offset++] = ctype;
284             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
285             break;
286         }
287         case AVRCP_NOTIFICATION_EVENT_TRACK_REACHED_START:{
288             uint16_t offset = 0;
289             uint8_t event[6];
290             event[offset++] = HCI_EVENT_AVRCP_META;
291             event[offset++] = sizeof(event) - 2;
292             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_TRACK_REACHED_START;
293             little_endian_store_16(event, offset, avrcp_cid);
294             offset += 2;
295             event[offset++] = ctype;
296             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
297             break;
298         }
299         case AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED:{
300             if (size < 1) break;
301             uint16_t offset = 0;
302             uint8_t event[7];
303             event[offset++] = HCI_EVENT_AVRCP_META;
304             event[offset++] = sizeof(event) - 2;
305             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_BATT_STATUS_CHANGED;
306             little_endian_store_16(event, offset, avrcp_cid);
307             offset += 2;
308             event[offset++] = ctype;
309             event[offset++] = payload[0];
310             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
311             break;
312         }
313 
314         case AVRCP_NOTIFICATION_EVENT_SYSTEM_STATUS_CHANGED:{
315             if (size < 1) break;
316             uint16_t offset = 0;
317             uint8_t event[7];
318             event[offset++] = HCI_EVENT_AVRCP_META;
319             event[offset++] = sizeof(event) - 2;
320             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_SYSTEM_STATUS_CHANGED;
321             little_endian_store_16(event, offset, avrcp_cid);
322             offset += 2;
323             event[offset++] = ctype;
324             event[offset++] = payload[0];
325             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
326             break;
327         }
328 
329         case AVRCP_NOTIFICATION_EVENT_PLAYER_APPLICATION_SETTING_CHANGED:
330         default:
331             log_info("avrcp: not implemented");
332             break;
333     }
334 }
335 
336 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){
337     btstack_assert(callback != NULL);
338 
339     uint8_t event[8];
340     int pos = 0;
341     event[pos++] = HCI_EVENT_AVRCP_META;
342     event[pos++] = sizeof(event) - 2;
343     event[pos++] = AVRCP_SUBEVENT_SHUFFLE_AND_REPEAT_MODE;
344     little_endian_store_16(event, pos, avrcp_cid);
345     pos += 2;
346     event[pos++] = ctype;
347     event[pos++] = repeat_mode;
348     event[pos++] = shuffle_mode;
349     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
350 }
351 
352 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){
353     uint8_t event[7];
354     int pos = 0;
355     event[pos++] = HCI_EVENT_AVRCP_META;
356     event[pos++] = sizeof(event) - 2;
357     event[pos++] = AVRCP_SUBEVENT_NOW_PLAYING_INFO_DONE;
358     little_endian_store_16(event, pos, avrcp_cid);
359     pos += 2;
360     event[pos++] = ctype;
361     event[pos++] = status;
362     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
363 }
364 
365 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){
366     uint8_t event[HCI_EVENT_BUFFER_SIZE];
367     int pos = 0;
368     event[pos++] = HCI_EVENT_AVRCP_META;
369     // reserve one byte for subevent type and data len
370     int data_len_pos = pos;
371     pos++;
372     int subevent_type_pos = pos;
373     pos++;
374     little_endian_store_16(event, pos, avrcp_cid);
375     pos += 2;
376     event[pos++] = ctype;
377 
378     switch (attr_id){
379         case AVRCP_MEDIA_ATTR_TITLE:
380             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TITLE_INFO;
381             event[pos++] = value_len;
382             (void)memcpy(event + pos, value, value_len);
383             break;
384         case AVRCP_MEDIA_ATTR_ARTIST:
385             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_ARTIST_INFO;
386             event[pos++] = value_len;
387             (void)memcpy(event + pos, value, value_len);
388             break;
389         case AVRCP_MEDIA_ATTR_ALBUM:
390             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_ALBUM_INFO;
391             event[pos++] = value_len;
392             (void)memcpy(event + pos, value, value_len);
393             break;
394         case AVRCP_MEDIA_ATTR_GENRE:
395             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_GENRE_INFO;
396             event[pos++] = value_len;
397             (void)memcpy(event + pos, value, value_len);
398             break;
399         case AVRCP_MEDIA_ATTR_SONG_LENGTH_MS:
400             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_SONG_LENGTH_MS_INFO;
401             if (value){
402                 little_endian_store_32(event, pos, btstack_atoi((char *)value));
403             } else {
404                 little_endian_store_32(event, pos, 0);
405             }
406             pos += 4;
407             break;
408         case AVRCP_MEDIA_ATTR_TRACK:
409             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TRACK_INFO;
410             if (value){
411                 event[pos++] = btstack_atoi((char *)value);
412             } else {
413                 event[pos++] = 0;
414             }
415             break;
416         case AVRCP_MEDIA_ATTR_TOTAL_NUM_ITEMS:
417             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TOTAL_TRACKS_INFO;
418             if (value){
419                 event[pos++] = btstack_atoi((char *)value);
420             } else {
421                 event[pos++] = 0;
422             }
423             break;
424         default:
425             break;
426     }
427     event[data_len_pos] = pos - 2;
428     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
429 }
430 
431 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){
432     btstack_assert(callback != NULL);
433 
434     uint8_t event[7];
435     int pos = 0;
436     event[pos++] = HCI_EVENT_AVRCP_META;
437     event[pos++] = sizeof(event) - 2;
438     event[pos++] = subevent;
439     little_endian_store_16(event, pos, avrcp_cid);
440     pos += 2;
441     event[pos++] = ctype;
442     event[pos++] = operation_id;
443     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
444 }
445 
446 static void avrcp_parser_reset(avrcp_connection_t * connection){
447     connection->list_offset = 0;
448     connection->num_attributes = 0;
449     connection->num_parsed_attributes = 0;
450     connection->parser_attribute_header_pos = 0;
451     connection->num_received_fragments = 0;
452     connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
453 }
454 
455 static void avrcp_parser_process_byte(uint8_t byte, avrcp_connection_t * connection, avrcp_command_type_t ctype){
456     uint16_t attribute_total_value_len;
457     uint32_t attribute_id;
458     switch(connection->parser_state){
459         case AVRCP_PARSER_GET_ATTRIBUTE_HEADER:
460             connection->parser_attribute_header[connection->parser_attribute_header_pos++] = byte;
461             connection->list_offset++;
462 
463             if (connection->parser_attribute_header_pos < AVRCP_ATTRIBUTE_HEADER_LEN) return;
464 
465             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
466             connection->attribute_value_len = btstack_min(attribute_total_value_len, AVRCP_MAX_ATTRIBUTE_SIZE);
467             if (connection->attribute_value_len > 0){
468                 // get ready for attribute value
469                 connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_VALUE;
470                 return;
471             }
472 
473             // emit empty attribute
474             attribute_id = big_endian_read_32(connection->parser_attribute_header, 0);
475             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);
476 
477             // done, see below
478             break;
479 
480         case AVRCP_PARSER_GET_ATTRIBUTE_VALUE:
481             connection->attribute_value[connection->attribute_value_offset++] = byte;
482             connection->list_offset++;
483 
484             if (connection->attribute_value_offset < connection->attribute_value_len) return;
485 
486             // emit (potentially partial) attribute
487             attribute_id = big_endian_read_32(connection->parser_attribute_header, 0);
488             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);
489 
490             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
491             if (connection->attribute_value_offset < attribute_total_value_len){
492                 // ignore rest of attribute
493                 connection->parser_state = AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE;
494                 return;
495             }
496 
497             // done, see below
498             break;
499 
500         case AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE:
501             connection->attribute_value_offset++;
502             connection->list_offset++;
503 
504             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
505             if (connection->attribute_value_offset < attribute_total_value_len) return;
506 
507             // done, see below
508             break;
509 
510         default:
511             return;
512     }
513 
514     // attribute fully read, check if more to come
515     if (connection->list_offset < connection->list_size){
516         // more to come, reset parser
517         connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
518         connection->parser_attribute_header_pos = 0;
519         connection->attribute_value_offset = 0;
520     } else {
521         // fully done
522         avrcp_parser_reset(connection);
523         avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 0);
524     }
525 }
526 
527 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){
528     int i;
529     for (i=0;i<num_bytes_to_read;i++){
530         avrcp_parser_process_byte(packet[i], connection, ctype);
531     }
532 }
533 
534 static void avrcp_send_cmd_with_avctp_fragmentation(avrcp_connection_t * connection){
535     l2cap_reserve_packet_buffer();
536     uint8_t * command = l2cap_get_outgoing_buffer();
537 
538     uint16_t max_payload_size;
539     avctp_packet_type_t avctp_packet_type = avctp_get_packet_type(connection, &max_payload_size);
540 
541     // non-fragmented: transport header (1) + PID (2)
542     // fragmented:     transport header (1) + num packets (1) + PID (2)
543 
544     // AVCTP header
545     // transport header : transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
546     uint16_t pos = 0;
547     command[pos++] = (connection->transaction_id << 4) | (avctp_packet_type << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
548 
549     switch (avctp_packet_type){
550         case AVCTP_SINGLE_PACKET:
551         case AVCTP_START_PACKET:
552             if (avctp_packet_type == AVCTP_START_PACKET){
553                 // num packets
554                 command[pos++] = ((connection->data_len + max_payload_size - 1) / max_payload_size);
555             }
556 
557             // Profile IDentifier (PID)
558             command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
559             command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
560 
561             // command_type
562             command[pos++] = connection->command_type;
563             // subunit_type | subunit ID
564             command[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
565             // opcode
566             command[pos++] = (uint8_t)connection->command_opcode;
567 
568             switch (connection->command_opcode){
569                 case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
570                     big_endian_store_24(command, pos, connection->company_id);
571                     pos += 3;
572                     command[pos++] = connection->pdu_id;
573                     command[pos++] = 0;                       // reserved(upper 6) | packet_type -> 0
574                     big_endian_store_16(command, pos, connection->data_len);     // parameter length
575                     pos += 2;
576                     break;
577                 case AVRCP_CMD_OPCODE_PASS_THROUGH:
578                     command[pos++] = connection->operation_id;
579                     command[pos++] = (uint8_t)connection->data_len;     // parameter length
580                     pos += 2;
581                     break;
582                 case AVRCP_CMD_OPCODE_UNIT_INFO:
583                     break;
584                 case AVRCP_CMD_OPCODE_SUBUNIT_INFO:
585                     break;
586                 default:
587                     btstack_assert(false);
588                     return;
589             }
590             break;
591         case AVCTP_CONTINUE_PACKET:
592         case AVCTP_END_PACKET:
593             break;
594         default:
595             btstack_assert(false);
596             return;
597     }
598     // compare number of bytes to store with the remaining buffer size
599     uint16_t bytes_to_copy = btstack_min(connection->data_len - connection->data_offset, max_payload_size - pos);
600 
601     (void)memcpy(command + pos, &connection->data[connection->data_offset], bytes_to_copy);
602     pos += bytes_to_copy;
603     connection->data_offset += bytes_to_copy;
604 
605     l2cap_send_prepared(connection->l2cap_signaling_cid, pos);
606 }
607 
608 static int avrcp_send_register_notification(avrcp_connection_t * connection, uint8_t event_id){
609     uint8_t command[18];
610     uint16_t pos = 0;
611     // transport header : transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
612     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
613     command[pos++] = (connection->transaction_id << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
614 
615     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
616     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
617     command[pos++] = AVRCP_CTYPE_NOTIFY;
618     command[pos++] = (AVRCP_SUBUNIT_TYPE_PANEL << 3) | AVRCP_SUBUNIT_ID;
619     command[pos++] = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
620 
621     big_endian_store_24(command, pos, BT_SIG_COMPANY_ID);
622     pos += 3;
623     command[pos++] = AVRCP_PDU_ID_REGISTER_NOTIFICATION;
624     command[pos++] = 0;                       // reserved(upper 6) | packet_type -> 0
625     big_endian_store_16(command, pos, 5);     // parameter length
626     pos += 2;
627     command[pos++] = event_id;
628     big_endian_store_32(command, pos, 1);     // send notification on playback position every second, for other notifications it is ignored
629     pos += 4;
630     return l2cap_send(connection->l2cap_signaling_cid, command, pos);
631 }
632 
633 static void avrcp_press_and_hold_timeout_handler(btstack_timer_source_t * timer){
634     UNUSED(timer);
635     avrcp_connection_t * connection = (avrcp_connection_t*) btstack_run_loop_get_timer_context(timer);
636     btstack_run_loop_set_timer(&connection->press_and_hold_cmd_timer, 2000); // 2 seconds timeout
637     btstack_run_loop_add_timer(&connection->press_and_hold_cmd_timer);
638     connection->state = AVCTP_W2_SEND_PRESS_COMMAND;
639     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
640 }
641 
642 static void avrcp_press_and_hold_timer_start(avrcp_connection_t * connection){
643     btstack_run_loop_remove_timer(&connection->press_and_hold_cmd_timer);
644     btstack_run_loop_set_timer_handler(&connection->press_and_hold_cmd_timer, avrcp_press_and_hold_timeout_handler);
645     btstack_run_loop_set_timer_context(&connection->press_and_hold_cmd_timer, connection);
646     btstack_run_loop_set_timer(&connection->press_and_hold_cmd_timer, 2000); // 2 seconds timeout
647     btstack_run_loop_add_timer(&connection->press_and_hold_cmd_timer);
648 }
649 
650 static void avrcp_press_and_hold_timer_stop(avrcp_connection_t * connection){
651     connection->press_and_hold_cmd_active = false;
652     btstack_run_loop_remove_timer(&connection->press_and_hold_cmd_timer);
653 }
654 
655 
656 static uint8_t avrcp_controller_request_pass_through_release_control_cmd(avrcp_connection_t * connection){
657     connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
658     if (connection->press_and_hold_cmd_active){
659         avrcp_press_and_hold_timer_stop(connection);
660     }
661     connection->operation_id = (avrcp_operation_id_t)(0x80 | connection->operation_id);
662     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
663     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
664     return ERROR_CODE_SUCCESS;
665 }
666 
667 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){
668     log_info("Send command %d", opid);
669     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
670     if (!connection){
671         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
672     }
673 
674     if (connection->state != AVCTP_CONNECTION_OPENED){
675         log_error("Connection in wrong state %d, expected %d. avrcp cid 0x%02x", connection->state, AVCTP_CONNECTION_OPENED, avrcp_cid);
676         return ERROR_CODE_COMMAND_DISALLOWED;
677     }
678     connection->state = AVCTP_W2_SEND_PRESS_COMMAND;
679     avrcp_controller_pass_through_command_data_init(connection, opid);
680 
681     if (playback_speed > 0){
682         connection->data[0] = playback_speed;
683         connection->data_len = 1;
684     }
685 
686     connection->press_and_hold_cmd_active = continuous_cmd;
687     if (connection->press_and_hold_cmd_active){
688         avrcp_press_and_hold_timer_start(connection);
689     }
690 
691     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
692     return ERROR_CODE_SUCCESS;
693 }
694 
695 static uint8_t request_single_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed){
696     return avrcp_controller_request_pass_through_press_control_cmd(avrcp_cid, opid, playback_speed, false);
697 }
698 
699 static uint8_t request_continuous_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed){
700     return avrcp_controller_request_pass_through_press_control_cmd(avrcp_cid, opid, playback_speed, true);
701 }
702 
703 static void avrcp_controller_get_capabilities_for_connection(avrcp_connection_t * connection, uint8_t capability_id){
704     connection->state = AVCTP_W2_SEND_COMMAND;
705     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_STATUS, AVRCP_PDU_ID_GET_CAPABILITIES);
706 
707     // Parameter Length
708     connection->data_len = 1;
709     connection->data[0] = capability_id;  // capability ID
710 
711     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
712 }
713 
714 static uint8_t avrcp_controller_register_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t event_id){
715     if (connection->target_supported_notifications_queried && (connection->target_supported_notifications & (1 << event_id)) == 0){
716         return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
717     }
718     if ( (connection->notifications_to_deregister & (1 << event_id)) != 0){
719         return ERROR_CODE_COMMAND_DISALLOWED;
720     }
721     if ( (connection->notifications_enabled & (1 << event_id)) != 0){
722         return ERROR_CODE_SUCCESS;
723     }
724     connection->notifications_to_register |= (1 << event_id);
725 
726     if (!connection->target_supported_notifications_queried){
727         connection->target_supported_notifications_suppress_emit_result = true;
728         avrcp_controller_get_capabilities_for_connection(connection, AVRCP_CAPABILITY_ID_EVENT);
729         return ERROR_CODE_SUCCESS;
730     }
731     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
732     return ERROR_CODE_SUCCESS;
733 }
734 
735 static uint8_t avrcp_controller_request_continuation(avrcp_connection_t * connection, avrcp_pdu_id_t pdu_id){
736     connection->state = AVCTP_W2_SEND_COMMAND;
737     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_CONTROL, pdu_id);
738 
739     // Parameter Length
740     connection->data_len = 3;
741     big_endian_store_16(connection->data, 0, 1);
742     connection->data[2] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
743 
744     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
745     return ERROR_CODE_SUCCESS;
746 }
747 
748 static uint8_t avrcp_controller_request_abort_continuation(avrcp_connection_t * connection){
749     return avrcp_controller_request_continuation(connection, AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE);
750 }
751 
752 static uint8_t avrcp_controller_request_continue_response(avrcp_connection_t * connection){
753     return avrcp_controller_request_continuation(connection, AVRCP_PDU_ID_REQUEST_CONTINUING_RESPONSE);
754 }
755 
756 static void avrcp_controller_handle_notification(avrcp_connection_t *connection, avrcp_command_type_t ctype, uint8_t *payload, uint16_t size) {
757     if (size < 1) return;
758     uint16_t pos = 0;
759     avrcp_notification_event_id_t event_id = (avrcp_notification_event_id_t) payload[pos++];
760     if ( (event_id < AVRCP_NOTIFICATION_EVENT_FIRST_INDEX) || (event_id > AVRCP_NOTIFICATION_EVENT_LAST_INDEX)){
761         return;
762     }
763 
764     uint16_t event_mask = (1 << event_id);
765     uint16_t reset_event_mask = ~event_mask;
766 
767     switch (ctype){
768         case AVRCP_CTYPE_RESPONSE_REJECTED:
769             connection->notifications_to_deregister &= reset_event_mask;
770             connection->notifications_to_register   &= reset_event_mask;
771             connection->initial_status_reported     &= reset_event_mask;
772             avrcp_controller_emit_notification_complete(connection, ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE, event_id, false);
773             return;
774 
775         case AVRCP_CTYPE_RESPONSE_INTERIM:
776             // register as enabled
777             connection->notifications_enabled |= event_mask;
778 
779             // check if initial value is already sent
780             if ( (connection->initial_status_reported & event_mask) != 0 ){
781                 return;
782             }
783             // emit event only once, initially
784             avrcp_controller_emit_notification_complete(connection, ERROR_CODE_SUCCESS, event_id, true);
785             connection->initial_status_reported |= event_mask;
786             // emit initial value after this switch
787             break;
788 
789         case AVRCP_CTYPE_RESPONSE_CHANGED_STABLE:
790             // received change, event is considered de-registered
791             // we are re-enabling it automatically, if it is not
792             // explicitly disabled
793             connection->notifications_enabled &= reset_event_mask;
794             if ((connection->notifications_to_deregister & event_mask) == 0){
795                 avrcp_controller_register_notification(connection, event_id);
796             } else {
797                 connection->notifications_to_deregister &= reset_event_mask;
798                 connection->notifications_to_register   &= reset_event_mask;
799                 connection->initial_status_reported     &= reset_event_mask;
800                 avrcp_controller_emit_notification_complete(connection, ERROR_CODE_SUCCESS, event_id, false);
801             }
802             break;
803 
804         default:
805             return;
806     }
807 
808     avrcp_controller_emit_notification_for_event_id(connection->avrcp_cid, event_id, ctype, payload + pos, size - pos);
809 }
810 
811 #ifdef ENABLE_AVCTP_FRAGMENTATION
812 static void avctp_reassemble_message(avrcp_connection_t * connection, avctp_packet_type_t packet_type, uint8_t *packet, uint16_t size){
813     // after header (transaction label and packet type)
814     uint16_t pos;
815     uint16_t bytes_to_store;
816 
817     switch (packet_type){
818         case AVCTP_START_PACKET:
819             if (size < 2) return;
820 
821             // store header
822             pos = 0;
823             connection->avctp_reassembly_buffer[pos] = packet[pos];
824             pos++;
825             connection->avctp_reassembly_size = pos;
826 
827             // NOTE: num packets not needed for reassembly, ignoring it does not pose security risk -> no need to store it
828             pos++;
829 
830             // PID in reassembled packet is at offset 1, it will be read later after the avctp_reassemble_message with AVCTP_END_PACKET is called
831 
832             bytes_to_store = btstack_min(size - pos, sizeof(connection->avctp_reassembly_buffer) - connection->avctp_reassembly_size);
833             memcpy(&connection->avctp_reassembly_buffer[connection->avctp_reassembly_size], &packet[pos], bytes_to_store);
834             connection->avctp_reassembly_size += bytes_to_store;
835             break;
836 
837         case AVCTP_CONTINUE_PACKET:
838         case AVCTP_END_PACKET:
839             if (size < 1) return;
840 
841             // store remaining data, ignore header
842             pos = 1;
843             bytes_to_store = btstack_min(size - pos, sizeof(connection->avctp_reassembly_buffer) - connection->avctp_reassembly_size);
844             memcpy(&connection->avctp_reassembly_buffer[connection->avctp_reassembly_size], &packet[pos], bytes_to_store);
845             connection->avctp_reassembly_size += bytes_to_store;
846             break;
847 
848         default:
849             return;
850     }
851 }
852 #endif
853 
854 static void avrcp_handle_l2cap_data_packet_for_signaling_connection(avrcp_connection_t * connection, uint8_t *packet, uint16_t size){
855     if (size < 6u) return;
856     uint8_t  pdu_id;
857     avrcp_packet_type_t  vendor_dependent_packet_type;
858 
859     uint16_t pos = 0;
860     connection->last_confirmed_transaction_id = packet[pos] >> 4;
861     avrcp_frame_type_t  frame_type =  (avrcp_frame_type_t)((packet[pos] >> 1) & 0x01);
862     avctp_packet_type_t packet_type = (avctp_packet_type_t)((packet[pos] >> 2) & 0x03);
863     pos++;
864 
865     if (frame_type != AVRCP_RESPONSE_FRAME) return;
866 
867     switch (packet_type){
868         case AVCTP_SINGLE_PACKET:
869             break;
870 
871 #ifdef ENABLE_AVCTP_FRAGMENTATION
872         case AVCTP_START_PACKET:
873         case AVCTP_CONTINUE_PACKET:
874             avctp_reassemble_message(connection, packet_type, packet, size);
875             return;
876 
877         case AVCTP_END_PACKET:
878             avctp_reassemble_message(connection, packet_type, packet, size);
879 
880             packet = connection->avctp_reassembly_buffer;
881             size   = connection->avctp_reassembly_size;
882             break;
883 #endif
884 
885         default:
886             return;
887     }
888 
889     pos += 2; // PID
890 
891     avrcp_command_type_t ctype = (avrcp_command_type_t) packet[pos++];
892 
893 #ifdef ENABLE_LOG_INFO
894     uint8_t byte_value = packet[pos];
895     avrcp_subunit_type_t subunit_type = (avrcp_subunit_type_t) (byte_value >> 3);
896     avrcp_subunit_type_t subunit_id   = (avrcp_subunit_type_t) (byte_value & 0x07);
897 #endif
898     pos++;
899 
900     uint8_t opcode = packet[pos++];
901     uint16_t param_length;
902 
903     switch (opcode){
904         case AVRCP_CMD_OPCODE_SUBUNIT_INFO:{
905             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
906             connection->state = AVCTP_CONNECTION_OPENED;
907 
908 #ifdef ENABLE_LOG_INFO
909             // page, extension code (1)
910             pos++;
911             uint8_t unit_type = packet[pos] >> 3;
912             uint8_t max_subunit_ID = packet[pos] & 0x07;
913             log_info("SUBUNIT INFO response: ctype 0x%02x (0C), subunit_type 0x%02x (1F), subunit_id 0x%02x (07), opcode 0x%02x (30), unit_type 0x%02x, max_subunit_ID %d", ctype, subunit_type, subunit_id, opcode, unit_type, max_subunit_ID);
914 #endif
915             break;
916         }
917         case AVRCP_CMD_OPCODE_UNIT_INFO:{
918             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
919             connection->state = AVCTP_CONNECTION_OPENED;
920 
921 #ifdef ENABLE_LOG_INFO
922             // byte value 7 (1)
923             pos++;
924             uint8_t unit_type = packet[pos] >> 3;
925             uint8_t unit = packet[pos] & 0x07;
926             pos++;
927             uint32_t company_id = big_endian_read_24(packet, pos);
928             log_info("UNIT INFO response: ctype 0x%02x (0C), subunit_type 0x%02x (1F), subunit_id 0x%02x (07), opcode 0x%02x (30), unit_type 0x%02x, unit %d, company_id 0x%06" PRIx32,
929                 ctype, subunit_type, subunit_id, opcode, unit_type, unit, company_id);
930 #endif
931             break;
932         }
933         case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
934 
935             if ((size - pos) < 7) return;
936 
937             // Company ID (3)
938             pos += 3;
939             pdu_id = packet[pos++];
940             vendor_dependent_packet_type = (avrcp_packet_type_t)(packet[pos++] & 0x03);
941             param_length = big_endian_read_16(packet, pos);
942             pos += 2;
943 
944             if ((size - pos) < param_length) return;
945 
946             // handle asynchronous notifications, without changing state
947             if (pdu_id == AVRCP_PDU_ID_REGISTER_NOTIFICATION){
948                 avrcp_controller_handle_notification(connection, ctype, packet + pos, size - pos);
949                 break;
950             }
951 
952             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE){
953                 log_info("AVRCP_CMD_OPCODE_VENDOR_DEPENDENT state %d", connection->state);
954                 return;
955             }
956             connection->state = AVCTP_CONNECTION_OPENED;
957 
958             log_info("VENDOR DEPENDENT response: pdu id 0x%02x, param_length %d, status %s", pdu_id, param_length, avrcp_ctype2str(ctype));
959             switch (pdu_id){
960                 case AVRCP_PDU_ID_GET_CURRENT_PLAYER_APPLICATION_SETTING_VALUE:{
961                     uint8_t num_attributes = packet[pos++];
962                     int i;
963                     avrcp_repeat_mode_t  repeat_mode =  AVRCP_REPEAT_MODE_INVALID;
964                     avrcp_shuffle_mode_t shuffle_mode = AVRCP_SHUFFLE_MODE_INVALID;
965                     for (i = 0; i < num_attributes; i++){
966                         uint8_t attribute_id    = packet[pos++];
967                         uint8_t value = packet[pos++];
968                         switch (attribute_id){
969                             case 0x02:
970                                 repeat_mode = (avrcp_repeat_mode_t) value;
971                                 break;
972                             case 0x03:
973                                 shuffle_mode = (avrcp_shuffle_mode_t) value;
974                                 break;
975                             default:
976                                 break;
977                         }
978                     }
979                     avrcp_controller_emit_repeat_and_shuffle_mode(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, repeat_mode, shuffle_mode);
980                     break;
981                 }
982 
983                 case AVRCP_PDU_ID_SET_PLAYER_APPLICATION_SETTING_VALUE:{
984                     uint16_t offset = 0;
985                     uint8_t event[6];
986                     event[offset++] = HCI_EVENT_AVRCP_META;
987                     event[offset++] = sizeof(event) - 2;
988                     event[offset++] = AVRCP_SUBEVENT_PLAYER_APPLICATION_VALUE_RESPONSE;
989                     little_endian_store_16(event, offset, connection->avrcp_cid);
990                     offset += 2;
991                     event[offset++] = ctype;
992                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
993                     break;
994                 }
995 
996                 case AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME:{
997                     uint16_t offset = 0;
998                     uint8_t event[7];
999                     event[offset++] = HCI_EVENT_AVRCP_META;
1000                     event[offset++] = sizeof(event) - 2;
1001                     event[offset++] = AVRCP_SUBEVENT_SET_ABSOLUTE_VOLUME_RESPONSE;
1002                     little_endian_store_16(event, offset, connection->avrcp_cid);
1003                     offset += 2;
1004                     event[offset++] = ctype;
1005                     event[offset++] = packet[pos++];
1006                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
1007                     break;
1008                 }
1009 
1010                 case AVRCP_PDU_ID_GET_CAPABILITIES:{
1011                     avrcp_capability_id_t capability_id = (avrcp_capability_id_t) packet[pos++];
1012                     uint8_t capability_count = 0;
1013                     if (param_length > 1){
1014                         capability_count = packet[pos++];
1015                     }
1016                     uint16_t i;
1017                     uint16_t offset = 0;
1018                     uint8_t event[10];
1019 
1020                     switch (capability_id){
1021 
1022                         case AVRCP_CAPABILITY_ID_COMPANY:
1023                             for (i = 0; (i < capability_count) && ((size - pos) >= 3); i++){
1024                                 uint32_t company_id = big_endian_read_24(packet, pos);
1025                                 pos += 3;
1026                                 log_info("  0x%06" PRIx32 ", ", company_id);
1027 
1028                                 offset = 0;
1029                                 event[offset++] = HCI_EVENT_AVRCP_META;
1030                                 event[offset++] = sizeof(event) - 2;
1031                                 event[offset++] = AVRCP_SUBEVENT_GET_CAPABILITY_COMPANY_ID;
1032                                 little_endian_store_16(event, offset, connection->avrcp_cid);
1033                                 offset += 2;
1034                                 event[offset++] = ctype;
1035                                 event[offset++] = 0;
1036                                 little_endian_store_24(event, offset, company_id);
1037                                 offset += 3;
1038                                 (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, offset);
1039                             }
1040 
1041                             offset = 0;
1042                             event[offset++] = HCI_EVENT_AVRCP_META;
1043                             event[offset++] = sizeof(event) - 2;
1044                             event[offset++] = AVRCP_SUBEVENT_GET_CAPABILITY_COMPANY_ID_DONE;
1045                             little_endian_store_16(event, offset, connection->avrcp_cid);
1046                             offset += 2;
1047                             event[offset++] = ctype;
1048                             event[offset++] = 0;
1049                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, offset);
1050                             break;
1051 
1052                         case AVRCP_CAPABILITY_ID_EVENT:
1053                             for (i = 0; (i < capability_count) && ((size - pos) >= 1); i++){
1054                                 uint8_t event_id = packet[pos++];
1055                                 connection->target_supported_notifications |= (1 << event_id);
1056                             }
1057 
1058                             // if the get supported events query is triggered by avrcp_controller_enable_notification call,
1059                             // avrcp_controller_emit_supported_events should be suppressed
1060                             if (connection->target_supported_notifications_suppress_emit_result){
1061                                 connection->target_supported_notifications_suppress_emit_result = false;
1062                                 // also, notification might not be supported
1063                                 // if so, emit AVRCP_SUBEVENT_ENABLE_NOTIFICATION_COMPLETE event to app,
1064                                 // and update notifications_to_register bitmap
1065                                 for (i = (uint8_t)AVRCP_NOTIFICATION_EVENT_FIRST_INDEX; i < (uint8_t) AVRCP_NOTIFICATION_EVENT_LAST_INDEX; i++){
1066                                     if ((connection->notifications_to_register & (1<<i)) != 0){
1067                                         if ((connection->target_supported_notifications & (1<<i)) == 0){
1068                                             avrcp_controller_emit_notification_complete(connection, ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE, i, false);
1069                                             connection->notifications_to_register &= ~(1 << i);
1070                                         }
1071                                     }
1072                                 }
1073                                 break;
1074                             }
1075                             // supported events are emitted only if the get supported events query
1076                             // is triggered by avrcp_controller_get_supported_events call
1077                             avrcp_controller_emit_supported_events(connection);
1078                             break;
1079 
1080                         default:
1081                             // ignore
1082                             break;
1083                     }
1084                     break;
1085                 }
1086 
1087                 case AVRCP_PDU_ID_GET_PLAY_STATUS:{
1088                     uint32_t song_length = big_endian_read_32(packet, pos);
1089                     pos += 4;
1090                     uint32_t song_position = big_endian_read_32(packet, pos);
1091                     pos += 4;
1092                     uint8_t play_status = packet[pos];
1093 
1094                     uint8_t event[15];
1095                     int offset = 0;
1096                     event[offset++] = HCI_EVENT_AVRCP_META;
1097                     event[offset++] = sizeof(event) - 2;
1098                     event[offset++] = AVRCP_SUBEVENT_PLAY_STATUS;
1099                     little_endian_store_16(event, offset, connection->avrcp_cid);
1100                     offset += 2;
1101                     event[offset++] = ctype;
1102                     little_endian_store_32(event, offset, song_length);
1103                     offset += 4;
1104                     little_endian_store_32(event, offset, song_position);
1105                     offset += 4;
1106                     event[offset++] = play_status;
1107                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
1108                     break;
1109                 }
1110 
1111                 case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:{
1112                     // TODO Review
1113                     switch (vendor_dependent_packet_type){
1114                         case AVRCP_START_PACKET:
1115                         case AVRCP_SINGLE_PACKET:
1116                             avrcp_parser_reset(connection);
1117                             connection->list_size = param_length;
1118                             connection->num_attributes = packet[pos++];
1119 
1120                             avrcp_controller_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
1121                             if (vendor_dependent_packet_type == AVRCP_START_PACKET){
1122                                 avrcp_controller_request_continue_response(connection);
1123                             }
1124                             break;
1125                         case AVRCP_CONTINUE_PACKET:
1126                         case AVRCP_END_PACKET:
1127                             connection->num_received_fragments++;
1128 
1129                             if (connection->num_received_fragments < connection->max_num_fragments){
1130                                 avrcp_controller_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
1131 
1132                                 if (vendor_dependent_packet_type == AVRCP_CONTINUE_PACKET){
1133                                     avrcp_controller_request_continue_response(connection);
1134                                 }
1135                             } else {
1136                                 avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 1);
1137                                 avrcp_parser_reset(connection);
1138                                 avrcp_controller_request_abort_continuation(connection);
1139                             }
1140                             break;
1141                         default:
1142                             // TODO check
1143                             btstack_assert(false);
1144                             break;
1145                     }
1146                 }
1147                 default:
1148                     break;
1149             }
1150             break;
1151         case AVRCP_CMD_OPCODE_PASS_THROUGH:{
1152             if ((size - pos) < 1) return;
1153             uint8_t operation_id = packet[pos++];
1154             switch (connection->state){
1155                 case AVCTP_W2_RECEIVE_PRESS_RESPONSE:
1156                     // trigger release for simple command:
1157                     if (!connection->press_and_hold_cmd_active){
1158                         connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
1159                         break;
1160                     }
1161                     // for press and hold, send release if it just has been requested, otherwise, wait for next repeat
1162                     if (connection->press_and_hold_cmd_release){
1163                         connection->press_and_hold_cmd_release = false;
1164                         connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
1165                     } else {
1166                         connection->state = AVCTP_W4_STOP;
1167                     }
1168                     break;
1169                 case AVCTP_W2_RECEIVE_RESPONSE:
1170                     connection->state = AVCTP_CONNECTION_OPENED;
1171                     break;
1172                 default:
1173                     break;
1174             }
1175             if (connection->state == AVCTP_W4_STOP){
1176                 avrcp_controller_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_START, connection->avrcp_cid, ctype, operation_id);
1177             }
1178             if (connection->state == AVCTP_CONNECTION_OPENED) {
1179                 // RELEASE response
1180                 operation_id = operation_id & 0x7F;
1181                 avrcp_controller_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_COMPLETE, connection->avrcp_cid, ctype, operation_id);
1182             }
1183             if (connection->state == AVCTP_W2_SEND_RELEASE_COMMAND){
1184                 // PRESS response
1185                 avrcp_controller_request_pass_through_release_control_cmd(connection);
1186             }
1187             break;
1188         }
1189         default:
1190             break;
1191     }
1192 
1193     // trigger pending notification reqistrations
1194     if ((connection->state == AVCTP_CONNECTION_OPENED) && connection->notifications_to_register){
1195         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1196     }
1197 }
1198 
1199 static void avrcp_controller_handle_can_send_now(avrcp_connection_t * connection){
1200     switch (connection->state){
1201         case AVCTP_W2_SEND_PRESS_COMMAND:
1202         case AVCTP_W2_SEND_COMMAND:
1203         case AVCTP_W2_SEND_RELEASE_COMMAND:
1204         case AVCTP_W2_SEND_AVCTP_FRAGMENTED_MESSAGE:
1205             avrcp_send_cmd_with_avctp_fragmentation(connection);
1206 
1207             if (connection->data_offset < connection->data_len){
1208                 avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1209                 return;
1210             }
1211             if (connection->state == AVCTP_W2_SEND_PRESS_COMMAND){
1212                 connection->state = AVCTP_W2_RECEIVE_PRESS_RESPONSE;
1213             } else {
1214                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
1215             }
1216             break;
1217         default:
1218             break;
1219     }
1220 
1221     // send register notification if queued
1222     if (connection->notifications_to_register != 0){
1223         uint8_t event_id;
1224         for (event_id = (uint8_t)AVRCP_NOTIFICATION_EVENT_FIRST_INDEX; event_id < (uint8_t)AVRCP_NOTIFICATION_EVENT_LAST_INDEX; event_id++){
1225             if (connection->notifications_to_register & (1<<event_id)){
1226                 connection->notifications_to_register &= ~ (1 << event_id);
1227                 avrcp_send_register_notification(connection, event_id);
1228                 return;
1229             }
1230         }
1231     }
1232 }
1233 
1234 static void avrcp_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
1235     avrcp_connection_t * connection;
1236 
1237     switch (packet_type) {
1238         case L2CAP_DATA_PACKET:
1239             connection = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, channel);
1240             avrcp_handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
1241             break;
1242 
1243         case HCI_EVENT_PACKET:
1244             switch (hci_event_packet_get_type(packet)){
1245                 case L2CAP_EVENT_CAN_SEND_NOW:
1246                     connection = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, channel);
1247                     avrcp_controller_handle_can_send_now(connection);
1248                     break;
1249             default:
1250                 break;
1251         }
1252         default:
1253             break;
1254     }
1255 }
1256 
1257 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){
1258     avrcp_create_sdp_record(1, service, service_record_handle, avrcp_controller_supports_browsing(supported_features), supported_features, service_name, service_provider_name);
1259 }
1260 
1261 void avrcp_controller_init(void){
1262     avrcp_controller_context.role = AVRCP_CONTROLLER;
1263     avrcp_controller_context.packet_handler = avrcp_controller_packet_handler;
1264     avrcp_register_controller_packet_handler(&avrcp_controller_packet_handler);
1265 }
1266 
1267 void avrcp_controller_deinit(void){
1268     memset(&avrcp_controller_context, 0, sizeof(avrcp_context_t));
1269 }
1270 
1271 void avrcp_controller_register_packet_handler(btstack_packet_handler_t callback){
1272     btstack_assert(callback != NULL);
1273     avrcp_controller_context.avrcp_callback = callback;
1274 }
1275 
1276 
1277 uint8_t avrcp_controller_play(uint16_t avrcp_cid){
1278     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PLAY, 0);
1279 }
1280 
1281 uint8_t avrcp_controller_stop(uint16_t avrcp_cid){
1282     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_STOP, 0);
1283 }
1284 
1285 uint8_t avrcp_controller_pause(uint16_t avrcp_cid){
1286     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PAUSE, 0);
1287 }
1288 
1289 uint8_t avrcp_controller_forward(uint16_t avrcp_cid){
1290     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FORWARD, 0);
1291 }
1292 
1293 uint8_t avrcp_controller_backward(uint16_t avrcp_cid){
1294     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_BACKWARD, 0);
1295 }
1296 
1297 uint8_t avrcp_controller_volume_up(uint16_t avrcp_cid){
1298     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_UP, 0);
1299 }
1300 
1301 uint8_t avrcp_controller_volume_down(uint16_t avrcp_cid){
1302     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_DOWN, 0);
1303 }
1304 
1305 uint8_t avrcp_controller_mute(uint16_t avrcp_cid){
1306     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_MUTE, 0);
1307 }
1308 
1309 uint8_t avrcp_controller_skip(uint16_t avrcp_cid){
1310     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_SKIP, 0);
1311 }
1312 
1313 uint8_t avrcp_controller_fast_forward(uint16_t avrcp_cid){
1314     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1315 }
1316 
1317 uint8_t avrcp_controller_rewind(uint16_t avrcp_cid){
1318     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
1319 }
1320 
1321 /* start continuous cmds */
1322 
1323 uint8_t avrcp_controller_start_press_and_hold_cmd(uint16_t avrcp_cid, avrcp_operation_id_t operation_id){
1324     return request_continuous_pass_through_press_control_cmd(avrcp_cid, operation_id, 0);
1325 }
1326 
1327 uint8_t avrcp_controller_press_and_hold_play(uint16_t avrcp_cid){
1328     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PLAY, 0);
1329 }
1330 uint8_t avrcp_controller_press_and_hold_stop(uint16_t avrcp_cid){
1331     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_STOP, 0);
1332 }
1333 uint8_t avrcp_controller_press_and_hold_pause(uint16_t avrcp_cid){
1334     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PAUSE, 0);
1335 }
1336 uint8_t avrcp_controller_press_and_hold_forward(uint16_t avrcp_cid){
1337     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FORWARD, 0);
1338 }
1339 uint8_t avrcp_controller_press_and_hold_backward(uint16_t avrcp_cid){
1340     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_BACKWARD, 0);
1341 }
1342 uint8_t avrcp_controller_press_and_hold_fast_forward(uint16_t avrcp_cid){
1343     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1344 }
1345 uint8_t avrcp_controller_press_and_hold_rewind(uint16_t avrcp_cid){
1346     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
1347 }
1348 uint8_t avrcp_controller_press_and_hold_volume_up(uint16_t avrcp_cid){
1349     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_UP, 0);
1350 }
1351 uint8_t avrcp_controller_press_and_hold_volume_down(uint16_t avrcp_cid){
1352     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_DOWN, 0);
1353 }
1354 uint8_t avrcp_controller_press_and_hold_mute(uint16_t avrcp_cid){
1355     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_MUTE, 0);
1356 }
1357 
1358 /* stop continuous cmds */
1359 uint8_t avrcp_controller_release_press_and_hold_cmd(uint16_t avrcp_cid){
1360     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1361     if (!connection){
1362         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1363     }
1364 
1365     switch (connection->state){
1366         // respond when we receive response for (repeated) press command
1367         case AVCTP_W2_RECEIVE_PRESS_RESPONSE:
1368             connection->press_and_hold_cmd_release = true;
1369             break;
1370 
1371         // release already sent or on the way, nothing to do
1372         case AVCTP_W2_RECEIVE_RESPONSE:
1373         case AVCTP_W2_SEND_RELEASE_COMMAND:
1374             break;
1375 
1376         // about to send next repeated press command or wait for it -> release right away
1377         case AVCTP_W2_SEND_PRESS_COMMAND:
1378         case AVCTP_W4_STOP:
1379             return avrcp_controller_request_pass_through_release_control_cmd(connection);
1380 
1381         // otherwise reject request
1382         default:
1383             return ERROR_CODE_COMMAND_DISALLOWED;
1384     }
1385     return ERROR_CODE_SUCCESS;
1386 }
1387 
1388 uint8_t avrcp_controller_enable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1389     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1390     if (!connection){
1391         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1392     }
1393     return avrcp_controller_register_notification(connection, event_id);
1394 }
1395 
1396 uint8_t avrcp_controller_disable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1397     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1398     if (!connection){
1399         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1400     }
1401     if (!connection->target_supported_notifications_queried){
1402         return ERROR_CODE_COMMAND_DISALLOWED;
1403     }
1404 
1405     if ((connection->target_supported_notifications & (1 << event_id)) == 0){
1406         return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1407     }
1408 
1409     if ((connection->notifications_enabled & (1 << event_id)) == 0){
1410         return ERROR_CODE_SUCCESS;
1411     }
1412 
1413     connection->notifications_to_deregister |= (1 << event_id);
1414     return ERROR_CODE_SUCCESS;
1415 }
1416 
1417 uint8_t avrcp_controller_unit_info(uint16_t avrcp_cid){
1418     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1419     if (!connection){
1420         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1421     }
1422     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1423 
1424     connection->state = AVCTP_W2_SEND_COMMAND;
1425     avrcp_controller_custome_command_data_init(connection, AVRCP_CMD_OPCODE_UNIT_INFO, AVRCP_CTYPE_STATUS, AVRCP_SUBUNIT_TYPE_UNIT, AVRCP_SUBUNIT_ID_IGNORE, 0, 0);
1426 
1427     memset(connection->data, 0xFF, 5);
1428     connection->data_len = 5;
1429     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1430     return ERROR_CODE_SUCCESS;
1431 }
1432 
1433 uint8_t avrcp_controller_subunit_info(uint16_t avrcp_cid){
1434     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1435     if (!connection){
1436         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1437     }
1438     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1439 
1440     connection->state = AVCTP_W2_SEND_COMMAND;
1441     avrcp_controller_custome_command_data_init(connection, AVRCP_CMD_OPCODE_SUBUNIT_INFO, AVRCP_CTYPE_STATUS, AVRCP_SUBUNIT_TYPE_UNIT, AVRCP_SUBUNIT_ID_IGNORE, 0, 0);
1442 
1443     memset(connection->data, 0xFF, 5);
1444     connection->data[0] = 7; // page: 0, extention_code: 7
1445     connection->data_len = 5;
1446     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1447     return ERROR_CODE_SUCCESS;
1448 }
1449 
1450 uint8_t avrcp_controller_get_supported_company_ids(uint16_t avrcp_cid){
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->state != AVCTP_CONNECTION_OPENED){
1456         return ERROR_CODE_COMMAND_DISALLOWED;
1457     }
1458     avrcp_controller_get_capabilities_for_connection(connection, AVRCP_CAPABILITY_ID_COMPANY);
1459     return ERROR_CODE_SUCCESS;
1460 }
1461 
1462 uint8_t avrcp_controller_get_supported_events(uint16_t avrcp_cid){
1463     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1464     if (!connection){
1465         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1466     }
1467     if (connection->state != AVCTP_CONNECTION_OPENED){
1468         return ERROR_CODE_COMMAND_DISALLOWED;
1469     }
1470 
1471     if (!connection->target_supported_notifications_queried){
1472         connection->target_supported_notifications_queried = true;
1473         avrcp_controller_get_capabilities_for_connection(connection, AVRCP_CAPABILITY_ID_EVENT);
1474         return ERROR_CODE_SUCCESS;
1475     }
1476 
1477     avrcp_controller_emit_supported_events(connection);
1478     return ERROR_CODE_SUCCESS;
1479 }
1480 
1481 uint8_t avrcp_controller_get_play_status(uint16_t avrcp_cid){
1482     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1483     if (!connection){
1484         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1485     }
1486     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1487 
1488     connection->state = AVCTP_W2_SEND_COMMAND;
1489     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_STATUS, AVRCP_PDU_ID_GET_PLAY_STATUS);
1490 
1491     connection->data_len = 0;
1492     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1493     return ERROR_CODE_SUCCESS;
1494 }
1495 
1496 uint8_t avrcp_controller_set_addressed_player(uint16_t avrcp_cid, uint16_t addressed_player_id){
1497     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1498     if (!connection){
1499         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1500     }
1501     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1502 
1503     connection->state = AVCTP_W2_SEND_COMMAND;
1504     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_CONTROL, AVRCP_PDU_ID_SET_ADDRESSED_PLAYER);
1505 
1506     connection->data_len = 2;
1507     big_endian_store_16(connection->data, 0, addressed_player_id);
1508 
1509     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1510     return ERROR_CODE_SUCCESS;
1511 }
1512 
1513 uint8_t avrcp_controller_get_element_attributes(uint16_t avrcp_cid, uint8_t num_attributes, avrcp_media_attribute_id_t * attributes){
1514     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1515     if (!connection){
1516         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1517     }
1518 
1519     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1520 
1521     if (num_attributes >= AVRCP_MEDIA_ATTR_RESERVED) {
1522         return ERROR_CODE_INVALID_HCI_COMMAND_PARAMETERS;
1523     }
1524 
1525     connection->state = AVCTP_W2_SEND_COMMAND;
1526     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_STATUS, AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES);
1527 
1528     uint8_t pos = 0;
1529     // write 8 bytes value
1530     memset(connection->data, pos, 8); // identifier: PLAYING
1531     pos += 8;
1532 
1533     uint8_t num_attributes_index = pos;
1534     pos++;
1535 
1536     // If num_attributes is set to zero, all attribute information shall be returned,
1537     // and the AttributeID field is omitted
1538     connection->data[num_attributes_index] = 0;
1539     uint8_t i;
1540     for (i = 0; i < num_attributes; i++){
1541         // ignore invalid attribute ID and "get all attributes"
1542         if (AVRCP_MEDIA_ATTR_ALL > attributes[i] && attributes[i] < AVRCP_MEDIA_ATTR_RESERVED){
1543             // every attribute is 4 bytes long
1544             big_endian_store_32(connection->data, pos, attributes[i]);
1545             pos += 4;
1546             connection->data[num_attributes_index]++;
1547         }
1548     }
1549 
1550     // Parameter Length
1551     connection->data_len = pos;
1552 
1553     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1554     return ERROR_CODE_SUCCESS;
1555 }
1556 
1557 uint8_t avrcp_controller_get_now_playing_info(uint16_t avrcp_cid){
1558     return avrcp_controller_get_element_attributes(avrcp_cid, 0, NULL);
1559 }
1560 
1561 uint8_t avrcp_controller_get_now_playing_info_for_media_attribute_id(uint16_t avrcp_cid, avrcp_media_attribute_id_t media_attribute_id){
1562     if (media_attribute_id == AVRCP_MEDIA_ATTR_ALL){
1563         return avrcp_controller_get_now_playing_info(avrcp_cid);
1564     }
1565     return avrcp_controller_get_element_attributes(avrcp_cid, 1, &media_attribute_id);
1566 }
1567 
1568 uint8_t avrcp_controller_set_absolute_volume(uint16_t avrcp_cid, uint8_t volume){
1569      avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1570     if (!connection){
1571         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1572     }
1573 
1574     //
1575     // allow sending of multiple set abs volume commands without waiting for response
1576     //
1577     uint8_t status = ERROR_CODE_COMMAND_DISALLOWED;
1578     switch (connection->state){
1579         case AVCTP_CONNECTION_OPENED:
1580             status = ERROR_CODE_SUCCESS;
1581             break;
1582         case AVCTP_W2_RECEIVE_RESPONSE:
1583             // - is pending response also set abs volume
1584             if (connection->command_opcode  != AVRCP_CMD_OPCODE_VENDOR_DEPENDENT) break;
1585             if (connection->command_type    != AVRCP_CTYPE_CONTROL)               break;
1586             if (connection->subunit_type    != AVRCP_SUBUNIT_TYPE_PANEL)          break;
1587             if (connection->subunit_id      != AVRCP_SUBUNIT_ID)                  break;
1588             if (connection->pdu_id          != AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME)  break;
1589             // - is next transaction id valid in window
1590             if (avrcp_controller_is_transaction_id_valid(connection, avrcp_controller_calc_next_transaction_label(connection->transaction_id_counter)) == false) break;
1591             status = ERROR_CODE_SUCCESS;
1592             break;
1593         default:
1594             break;
1595     }
1596     if (status != ERROR_CODE_SUCCESS) return status;
1597 
1598     connection->state = AVCTP_W2_SEND_COMMAND;
1599     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_CONTROL, AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME);
1600 
1601     // Parameter Length
1602     connection->data_len = 1;
1603     connection->data[0] = volume;
1604 
1605     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1606     return ERROR_CODE_SUCCESS;
1607 }
1608 
1609 uint8_t avrcp_controller_query_shuffle_and_repeat_modes(uint16_t avrcp_cid){
1610     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1611     if (!connection){
1612         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1613     }
1614     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1615 
1616     connection->state = AVCTP_W2_SEND_COMMAND;
1617     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_STATUS, AVRCP_PDU_ID_GET_CURRENT_PLAYER_APPLICATION_SETTING_VALUE);
1618 
1619     connection->data_len = 5;
1620     connection->data[0] = 4;                     // NumPlayerApplicationSettingAttributeID
1621     // PlayerApplicationSettingAttributeID1 AVRCP Spec, Appendix F, 133
1622     connection->data[1] = 0x01;   // equalizer  (1-OFF, 2-ON)
1623     connection->data[2] = 0x02;   // repeat     (1-off, 2-single track, 3-all tracks, 4-group repeat)
1624     connection->data[3] = 0x03;   // shuffle    (1-off, 2-all tracks, 3-group shuffle)
1625     connection->data[4] = 0x04;   // scan       (1-off, 2-all tracks, 3-group scan)
1626 
1627     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1628     return ERROR_CODE_SUCCESS;
1629 }
1630 
1631 static uint8_t avrcp_controller_set_current_player_application_setting_value(uint16_t avrcp_cid, uint8_t attr_id, uint8_t attr_value){
1632     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1633     if (!connection){
1634         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1635     }
1636     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1637 
1638     connection->state = AVCTP_W2_SEND_COMMAND;
1639     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_CONTROL, AVRCP_PDU_ID_SET_PLAYER_APPLICATION_SETTING_VALUE);
1640 
1641     // Parameter Length
1642     connection->data_len = 3;
1643     connection->data[0]  = 2;
1644     connection->data[1]  = attr_id;
1645     connection->data[2]  = attr_value;
1646 
1647     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1648     return ERROR_CODE_SUCCESS;
1649 }
1650 
1651 uint8_t avrcp_controller_set_shuffle_mode(uint16_t avrcp_cid, avrcp_shuffle_mode_t mode){
1652     if ((mode < AVRCP_SHUFFLE_MODE_OFF) || (mode > AVRCP_SHUFFLE_MODE_GROUP)) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1653     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x03, mode);
1654 }
1655 
1656 uint8_t avrcp_controller_set_repeat_mode(uint16_t avrcp_cid, avrcp_repeat_mode_t mode){
1657     if ((mode < AVRCP_REPEAT_MODE_OFF) || (mode > AVRCP_REPEAT_MODE_GROUP)) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1658     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x02, mode);
1659 }
1660 
1661 uint8_t avrcp_controller_play_item_for_scope(uint16_t avrcp_cid, uint8_t * uid, uint16_t uid_counter, avrcp_browsing_scope_t scope){
1662     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1663     if (!connection){
1664         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1665     }
1666     if (connection->state != AVCTP_CONNECTION_OPENED){
1667         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1668         return ERROR_CODE_COMMAND_DISALLOWED;
1669     }
1670     connection->state = AVCTP_W2_SEND_COMMAND;
1671     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_CONTROL, AVRCP_PDU_ID_PLAY_ITEM);
1672 
1673     // Parameter Length
1674     connection->data_len = 11;
1675     connection->data[0]  = scope;
1676     memset(&connection->data[1], 0, 8);
1677     if (uid){
1678         (void)memcpy(&connection->data[1], uid, 8);
1679     }
1680     big_endian_store_16(connection->data, 9, uid_counter);
1681 
1682     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1683     return ERROR_CODE_SUCCESS;
1684 }
1685 
1686 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){
1687     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1688     if (!connection){
1689         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1690     }
1691     if (connection->state != AVCTP_CONNECTION_OPENED){
1692         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1693         return ERROR_CODE_COMMAND_DISALLOWED;
1694     }
1695 
1696     connection->state = AVCTP_W2_SEND_COMMAND;
1697     avrcp_controller_vendor_dependent_command_data_init(connection, AVRCP_CTYPE_CONTROL, AVRCP_PDU_ID_ADD_TO_NOW_PLAYING);
1698 
1699     // Parameter Length
1700     connection->data_len = 11;
1701     connection->data[0]  = scope;
1702     memset(&connection->data[1], 0, 8);
1703     if (uid){
1704         (void)memcpy(&connection->data[1], uid, 8);
1705     }
1706     big_endian_store_16(connection->data, 9, uid_counter);
1707 
1708     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1709     return ERROR_CODE_SUCCESS;
1710 }
1711 
1712 uint8_t avrcp_controller_set_max_num_fragments(uint16_t avrcp_cid, uint8_t max_num_fragments){
1713     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1714     if (!connection){
1715         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1716     }
1717     connection->max_num_fragments = max_num_fragments;
1718     return ERROR_CODE_SUCCESS;
1719 }
1720 
1721 
1722 uint8_t avrcp_controller_send_custom_command(uint16_t avrcp_cid,
1723     avrcp_command_type_t command_type,
1724     avrcp_subunit_type_t subunit_type, avrcp_subunit_id_t subunit_id,
1725     avrcp_pdu_id_t pdu_id, uint32_t company_id,
1726     const uint8_t * data, uint16_t data_len){
1727 
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) return ERROR_CODE_COMMAND_DISALLOWED;
1733 
1734     connection->state = AVCTP_W2_SEND_AVCTP_FRAGMENTED_MESSAGE;
1735     avrcp_controller_custome_command_data_init(connection, AVRCP_CMD_OPCODE_VENDOR_DEPENDENT, command_type, subunit_type, subunit_id, pdu_id, company_id);
1736 
1737     connection->data = (uint8_t *)data;
1738     connection->data_len = data_len;
1739 
1740     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1741     return ERROR_CODE_SUCCESS;
1742 }
1743