xref: /btstack/src/ble/gatt-service/cycling_power_service_server.c (revision a8d51f092f1b660d0f6921369ad2bc3f9368296c)
1 /*
2  * Copyright (C) 2014 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 MATTHIAS
24  * RINGWALD 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__ "cycling_power_service_server.c"
39 
40 
41 #include "bluetooth.h"
42 #include "btstack_defines.h"
43 #include "bluetooth_data_types.h"
44 #include "btstack_event.h"
45 #include "ble/att_db.h"
46 #include "ble/att_server.h"
47 #include "btstack_util.h"
48 #include "bluetooth_gatt.h"
49 #include "btstack_debug.h"
50 #include "l2cap.h"
51 #include "hci.h"
52 
53 #include "ble/gatt-service/cycling_power_service_server.h"
54 
55 #define CYCLING_POWER_MAX_BROACAST_MSG_SIZE         31
56 #define CONTROL_POINT_PROCEDURE_TIMEOUT_MS          30
57 #define CYCLING_POWER_MEASUREMENT_FLAGS_CLEARED     0xFFFF
58 
59 typedef enum {
60     CP_MASK_BIT_PEDAL_POWER_BALANCE = 0,
61     CP_MASK_BIT_ACCUMULATED_TORQUE,
62     CP_MASK_BIT_WHEEL_REVOLUTION_DATA,
63     CP_MASK_BIT_CRANK_REVOLUTION_DATA,
64     CP_MASK_BIT_EXTREME_MAGNITUDES,
65     CP_MASK_BIT_EXTREME_ANGLES,
66     CP_MASK_BIT_TOP_DEAD_SPOT_ANGLE,
67     CP_MASK_BIT_BOTTOM_DEAD_SPOT_ANGLE,
68     CP_MASK_BIT_ACCUMULATED_ENERGY,
69     CP_MASK_BIT_RESERVED
70 } cycling_power_mask_bit_t;
71 
72 typedef enum {
73     CP_OPCODE_IDLE = 0,
74     CP_OPCODE_SET_CUMULATIVE_VALUE,
75     CP_OPCODE_UPDATE_SENSOR_LOCATION,
76     CP_OPCODE_REQUEST_SUPPORTED_SENSOR_LOCATIONS,
77     CP_OPCODE_SET_CRANK_LENGTH,
78     CP_OPCODE_REQUEST_CRANK_LENGTH,
79     CP_OPCODE_SET_CHAIN_LENGTH,
80     CP_OPCODE_REQUEST_CHAIN_LENGTH,
81     CP_OPCODE_SET_CHAIN_WEIGHT,
82     CP_OPCODE_REQUEST_CHAIN_WEIGHT,
83     CP_OPCODE_SET_SPAN_LENGTH,
84     CP_OPCODE_REQUEST_SPAN_LENGTH,
85     CP_OPCODE_START_OFFSET_COMPENSATION,
86     CP_OPCODE_MASK_CYCLING_POWER_MEASUREMENT_CHARACTERISTIC_CONTENT,
87     CP_OPCODE_REQUEST_SAMPLING_RATE,
88     CP_OPCODE_REQUEST_FACTORY_CALIBRATION_DATE,
89     CP_OPCODE_START_ENHANCED_OFFSET_COMPENSATION,
90     CP_OPCODE_RESPONSE_CODE = 32
91 } cycling_power_opcode_t;
92 
93 typedef enum {
94     CP_RESPONSE_VALUE_SUCCESS = 1,
95     CP_RESPONSE_VALUE_OP_CODE_NOT_SUPPORTED,
96     CP_RESPONSE_VALUE_INVALID_PARAMETER,
97     CP_RESPONSE_VALUE_OPERATION_FAILED,
98     CP_RESPONSE_VALUE_NOT_AVAILABLE,
99     CP_RESPONSE_VALUE_W4_VALUE_AVAILABLE
100 } cycling_power_response_value_t;
101 
102 typedef enum {
103     CP_CONNECTION_INTERVAL_STATUS_NONE = 0,
104     CP_CONNECTION_INTERVAL_STATUS_RECEIVED,
105     CP_CONNECTION_INTERVAL_STATUS_ACCEPTED,
106     CP_CONNECTION_INTERVAL_STATUS_W4_L2CAP_RESPONSE,
107     CP_CONNECTION_INTERVAL_STATUS_W4_UPDATE,
108     CP_CONNECTION_INTERVAL_STATUS_REJECTED
109 } cycling_power_con_interval_status_t;
110 
111 typedef struct {
112     hci_con_handle_t con_handle;
113     // GATT connection management
114     uint16_t con_interval;
115     uint16_t con_interval_min;
116     uint16_t con_interval_max;
117     cycling_power_con_interval_status_t  con_interval_status;
118 
119     // Cycling Power Measurement
120     uint16_t measurement_value_handle;
121     int16_t  instantaneous_power_watt;
122 
123     cycling_power_pedal_power_balance_reference_t  pedal_power_balance_reference;
124     uint8_t  pedal_power_balance_percentage;    // percentage, resolution 1/2,
125                                                 // If the sensor provides the power balance referenced to the left pedal,
126                                                 // the power balance is calculated as [LeftPower/(LeftPower + RightPower)]*100 in units of percent
127 
128     cycling_power_torque_source_t torque_source;
129     uint16_t accumulated_torque_m;              // meters, resolution 1/32,
130                                                 // The Accumulated Torque value may decrease
131     // wheel revolution data:
132     uint32_t cumulative_wheel_revolutions;      // CANNOT roll over
133     uint16_t last_wheel_event_time_s;           // seconds, resolution 1/2048
134     // crank revolution data:
135     uint16_t cumulative_crank_revolutions;
136     uint16_t last_crank_event_time_s;           // seconds, resolution 1/1024
137     // extreme force magnitudes
138     int16_t  maximum_force_magnitude_newton;
139     int16_t  minimum_force_magnitude_newton;
140     int16_t  maximum_torque_magnitude_newton_m;     // newton meters, resolution 1/32
141     int16_t  minimum_torque_magnitude_newton_m;     // newton meters, resolution 1/32
142     // extreme angles
143     uint16_t maximum_angle_deg;                 // 12bit, degrees
144     uint16_t minimum_angle_deg;                 // 12bit, degrees, concatenated with previous into 3 octets
145                                                 // i.e. if the Maximum Angle is 0xABC and the Minimum Angle is 0x123, the transmitted value is 0x123ABC.
146     uint16_t top_dead_spot_angle_deg;
147     uint16_t bottom_dead_spot_angle_deg;            // The Bottom Dead Spot Angle field represents the crank angle when the value of the Instantaneous Power value becomes negative.
148     uint16_t accumulated_energy_kJ;             // kilojoules; CANNOT roll over
149 
150     // uint8_t  offset_compensation;
151 
152     // CP Measurement Notification (Client Characteristic Configuration)
153     uint16_t measurement_client_configuration_descriptor_handle;
154     uint16_t measurement_client_configuration_descriptor_notify;
155     btstack_context_callback_registration_t measurement_notify_callback;
156 
157     // CP Measurement Broadcast (Server Characteristic Configuration)
158     uint16_t measurement_server_configuration_descriptor_handle;
159     uint16_t measurement_server_configuration_descriptor_broadcast;
160     btstack_context_callback_registration_t measurement_broadcast_callback;
161 
162     // Cycling Power Feature
163     uint16_t feature_value_handle;
164     uint32_t feature_flags;                             // see cycling_power_feature_flag_t
165     uint16_t masked_measurement_flags;
166     uint16_t default_measurement_flags;
167 
168     // Sensor Location
169     uint16_t sensor_location_value_handle;
170     cycling_power_sensor_location_t sensor_location;    // see cycling_power_sensor_location_t
171     cycling_power_sensor_location_t * supported_sensor_locations;
172     uint16_t num_supported_sensor_locations;
173     uint16_t crank_length_mm;                           // resolution 1/2 mm
174     uint16_t chain_length_mm;                           // resolution 1 mm
175     uint16_t chain_weight_g;                            // resolution 1 gram
176     uint16_t span_length_mm;                            // resolution 1 mm
177 
178     gatt_date_time_t factory_calibration_date;
179 
180     uint8_t  sampling_rate_hz;                          // resolution 1 Herz
181 
182     int16_t  current_force_magnitude_newton;
183     int16_t  current_torque_magnitude_newton_m;     // newton meters, resolution 1/32
184     uint16_t manufacturer_company_id;
185     uint8_t num_manufacturer_specific_data;
186     uint8_t * manufacturer_specific_data;
187 
188     // Cycling Power Vector
189     uint16_t vector_value_handle;
190     uint16_t vector_cumulative_crank_revolutions;
191     uint16_t vector_last_crank_event_time_s;                            // seconds, resolution 1/1024
192     uint16_t vector_first_crank_measurement_angle_deg;
193     int16_t  * vector_instantaneous_force_magnitude_newton_array;           // newton
194     int force_magnitude_count;
195     int16_t  * vector_instantaneous_torque_magnitude_newton_per_m_array;    // newton per meter, resolution 1/32
196     int torque_magnitude_count;
197     cycling_power_instantaneous_measurement_direction_t vector_instantaneous_measurement_direction;
198 
199     // CP Vector Notification (Client Characteristic Configuration)
200     uint16_t vector_client_configuration_descriptor_handle;
201     uint16_t vector_client_configuration_descriptor_notify;
202     btstack_context_callback_registration_t vector_notify_callback;
203 
204     // CP Control Point
205     uint16_t control_point_value_handle;
206     // CP Control Point Indication (Client Characteristic Configuration)
207     uint16_t control_point_client_configuration_descriptor_handle;
208     uint16_t control_point_client_configuration_descriptor_indicate;
209     btstack_context_callback_registration_t control_point_indicate_callback;
210 
211     cycling_power_opcode_t request_opcode;
212     cycling_power_response_value_t response_value;
213 
214     btstack_packet_handler_t calibration_callback;
215     uint8_t w4_indication_complete;
216 } cycling_power_t;
217 
218 static att_service_handler_t cycling_power_service;
219 static cycling_power_t cycling_power;
220 static btstack_packet_callback_registration_t hci_event_callback_registration;
221 
222 static uint16_t cycling_power_service_read_callback(hci_con_handle_t con_handle, uint16_t attribute_handle, uint16_t offset, uint8_t * buffer, uint16_t buffer_size){
223     UNUSED(con_handle);
224     UNUSED(attribute_handle);
225     UNUSED(offset);
226     cycling_power_t * instance = &cycling_power;
227 
228     if (attribute_handle == instance->measurement_client_configuration_descriptor_handle){
229         if (buffer && (buffer_size >= 2u)){
230             little_endian_store_16(buffer, 0, instance->measurement_client_configuration_descriptor_notify);
231         }
232         return 2;
233     }
234 
235     if (attribute_handle == instance->measurement_server_configuration_descriptor_handle){
236         if (buffer && (buffer_size >= 2u)){
237             little_endian_store_16(buffer, 0, instance->measurement_server_configuration_descriptor_broadcast);
238         }
239         return 2;
240     }
241 
242     if (attribute_handle == instance->vector_client_configuration_descriptor_handle){
243         if (buffer && (buffer_size >= 2u)){
244             little_endian_store_16(buffer, 0, instance->vector_client_configuration_descriptor_notify);
245         }
246         return 2;
247     }
248 
249     if (attribute_handle == instance->control_point_client_configuration_descriptor_handle){
250         if (buffer && (buffer_size >= 2u)){
251             little_endian_store_16(buffer, 0, instance->control_point_client_configuration_descriptor_indicate);
252         }
253         return 2;
254     }
255 
256     if (attribute_handle == instance->feature_value_handle){
257         if (buffer && (buffer_size >= 4u)){
258             little_endian_store_32(buffer, 0, instance->feature_flags);
259         }
260         return 4;
261     }
262 
263     if (attribute_handle == instance->sensor_location_value_handle){
264         if (buffer && (buffer_size >= 1u)){
265             buffer[0] = instance->sensor_location;
266         }
267         return 1;
268     }
269     return 0;
270 }
271 
272 static int has_feature(cycling_power_feature_flag_t feature){
273     cycling_power_t * instance = &cycling_power;
274     return (instance->feature_flags & (1u << feature)) != 0u;
275 }
276 
277 static int cycling_power_vector_instantaneous_measurement_direction(void){
278     cycling_power_t * instance = &cycling_power;
279     return instance->vector_instantaneous_measurement_direction;
280 }
281 
282 static uint16_t cycling_power_service_default_measurement_flags(void){
283     cycling_power_t * instance = &cycling_power;
284     uint16_t measurement_flags = 0;
285     uint8_t flag[] = {
286         (uint8_t) has_feature(CP_FEATURE_FLAG_PEDAL_POWER_BALANCE_SUPPORTED),
287         (uint8_t) has_feature(CP_FEATURE_FLAG_PEDAL_POWER_BALANCE_SUPPORTED) && instance->pedal_power_balance_reference,
288         (uint8_t) has_feature(CP_FEATURE_FLAG_ACCUMULATED_TORQUE_SUPPORTED),
289         (uint8_t) has_feature(CP_FEATURE_FLAG_ACCUMULATED_TORQUE_SUPPORTED) && instance->torque_source,
290         (uint8_t) has_feature(CP_FEATURE_FLAG_WHEEL_REVOLUTION_DATA_SUPPORTED),
291         (uint8_t) has_feature(CP_FEATURE_FLAG_CRANK_REVOLUTION_DATA_SUPPORTED),
292         (uint8_t) has_feature(CP_FEATURE_FLAG_EXTREME_MAGNITUDES_SUPPORTED) && (has_feature(CP_FEATURE_FLAG_SENSOR_MEASUREMENT_CONTEXT) == CP_SENSOR_MEASUREMENT_CONTEXT_FORCE),
293         (uint8_t) has_feature(CP_FEATURE_FLAG_EXTREME_MAGNITUDES_SUPPORTED) && (has_feature(CP_FEATURE_FLAG_SENSOR_MEASUREMENT_CONTEXT) == CP_SENSOR_MEASUREMENT_CONTEXT_TORQUE),
294         (uint8_t) has_feature(CP_FEATURE_FLAG_EXTREME_ANGLES_SUPPORTED),
295         (uint8_t) has_feature(CP_FEATURE_FLAG_TOP_AND_BOTTOM_DEAD_SPOT_ANGLE_SUPPORTED),
296         (uint8_t) has_feature(CP_FEATURE_FLAG_TOP_AND_BOTTOM_DEAD_SPOT_ANGLE_SUPPORTED),
297         (uint8_t) has_feature(CP_FEATURE_FLAG_ACCUMULATED_ENERGY_SUPPORTED),
298         (uint8_t) has_feature(CP_FEATURE_FLAG_OFFSET_COMPENSATION_INDICATOR_SUPPORTED)
299     };
300 
301     int i;
302     for (i = CP_MEASUREMENT_FLAG_PEDAL_POWER_BALANCE_PRESENT; i <= CP_MEASUREMENT_FLAG_OFFSET_COMPENSATION_INDICATOR; i++){
303         measurement_flags |= flag[i] << i;
304     }
305 
306     return measurement_flags;
307 }
308 
309 static uint16_t cycling_power_service_get_measurement_flags(cycling_power_t * instance){
310     if (!instance) return 0;
311     if (instance->masked_measurement_flags != CYCLING_POWER_MEASUREMENT_FLAGS_CLEARED){
312         return instance->masked_measurement_flags;
313     }
314     if (instance->default_measurement_flags == CYCLING_POWER_MEASUREMENT_FLAGS_CLEARED){
315         instance->default_measurement_flags = cycling_power_service_default_measurement_flags();
316     }
317     return instance->default_measurement_flags;
318 }
319 
320 
321 uint16_t cycling_power_service_measurement_flags(void){
322     cycling_power_t * instance = &cycling_power;
323     return cycling_power_service_get_measurement_flags(instance);
324 }
325 
326 uint8_t cycling_power_service_vector_flags(void){
327     uint8_t vector_flags = 0;
328     uint8_t flag[] = {
329         (uint8_t )has_feature(CP_FEATURE_FLAG_CRANK_REVOLUTION_DATA_SUPPORTED),
330         (uint8_t )has_feature(CP_FEATURE_FLAG_EXTREME_ANGLES_SUPPORTED),
331         (uint8_t )has_feature(CP_FEATURE_FLAG_EXTREME_MAGNITUDES_SUPPORTED) && (has_feature(CP_FEATURE_FLAG_SENSOR_MEASUREMENT_CONTEXT) == CP_SENSOR_MEASUREMENT_CONTEXT_FORCE),
332         (uint8_t )has_feature(CP_FEATURE_FLAG_EXTREME_MAGNITUDES_SUPPORTED) && (has_feature(CP_FEATURE_FLAG_SENSOR_MEASUREMENT_CONTEXT) == CP_SENSOR_MEASUREMENT_CONTEXT_TORQUE),
333         (uint8_t )has_feature(CP_FEATURE_FLAG_INSTANTANEOUS_MEASUREMENT_DIRECTION_SUPPORTED) && cycling_power_vector_instantaneous_measurement_direction()
334     };
335 
336     int i;
337     for (i = CP_VECTOR_FLAG_CRANK_REVOLUTION_DATA_PRESENT; i <= CP_VECTOR_FLAG_INSTANTANEOUS_MEASUREMENT_DIRECTION; i++){
338         vector_flags |= flag[i] << i;
339     }
340     return vector_flags;
341 }
342 
343 static void cycling_power_service_vector_can_send_now(void * context){
344     cycling_power_t * instance = (cycling_power_t *) context;
345     if (!instance){
346         log_error("cycling_power_service_measurement_can_send_now: instance is null");
347         return;
348     }
349     uint8_t value[50];
350     uint8_t vector_flags = cycling_power_service_vector_flags();
351     int pos = 0;
352 
353     value[pos++] = vector_flags;
354     int i;
355     for (i = CP_VECTOR_FLAG_CRANK_REVOLUTION_DATA_PRESENT; i <= CP_VECTOR_FLAG_INSTANTANEOUS_MEASUREMENT_DIRECTION; i++){
356         if ((vector_flags & (1u << i)) == 0u) continue;
357         switch ((cycling_power_vector_flag_t) i){
358             case CP_VECTOR_FLAG_CRANK_REVOLUTION_DATA_PRESENT:
359                 little_endian_store_16(value, pos, instance->cumulative_crank_revolutions);
360                 pos += 2;
361                 little_endian_store_16(value, pos, instance->last_crank_event_time_s);
362                 pos += 2;
363                 break;
364             case CP_VECTOR_FLAG_INSTANTANEOUS_FORCE_MAGNITUDE_ARRAY_PRESENT:{
365                 uint16_t att_mtu = att_server_get_mtu(instance->con_handle);
366                 uint16_t bytes_left = 0;
367                 if (att_mtu > (pos + 3u)){
368                     bytes_left = btstack_min(sizeof(value), att_mtu - 3u - pos);
369                 }
370                 while ((bytes_left > 2u) && instance->force_magnitude_count){
371                     little_endian_store_16(value, pos, instance->vector_instantaneous_force_magnitude_newton_array[0]);
372                     pos += 2;
373                     bytes_left -= 2u;
374                     instance->vector_instantaneous_force_magnitude_newton_array++;
375                     instance->force_magnitude_count--;
376                 }
377                 break;
378             }
379             case CP_VECTOR_FLAG_INSTANTANEOUS_TORQUE_MAGNITUDE_ARRAY_PRESENT:{
380                 uint16_t att_mtu = att_server_get_mtu(instance->con_handle);
381                 uint16_t bytes_left = 0;
382                 if (att_mtu > (pos + 3u)){
383                     bytes_left = btstack_min(sizeof(value), att_mtu - 3u - pos);
384                 }
385 
386                 while ((bytes_left > 2u) && instance->torque_magnitude_count){
387                     little_endian_store_16(value, pos, instance->vector_instantaneous_torque_magnitude_newton_per_m_array[0]);
388                     pos += 2;
389                     bytes_left -= 2u;
390                     instance->vector_instantaneous_torque_magnitude_newton_per_m_array++;
391                     instance->torque_magnitude_count--;
392                 }
393                 break;
394             }
395             case CP_VECTOR_FLAG_FIRST_CRANK_MEASUREMENT_ANGLE_PRESENT:
396                 // printf("CP_VECTOR_FLAG_FIRST_CRANK_MEASUREMENT_ANGLE_PRESENT \n");
397                 little_endian_store_16(value, pos, instance->vector_first_crank_measurement_angle_deg);
398                 pos += 2;
399                 break;
400             case CP_VECTOR_FLAG_INSTANTANEOUS_MEASUREMENT_DIRECTION:
401                 break;
402             default:
403                 break;
404         }
405     }
406 
407     att_server_notify(instance->con_handle, instance->vector_value_handle, &value[0], pos);
408 }
409 
410 static int cycling_power_measurement_flag_value_size(cycling_power_measurement_flag_t flag){
411     switch (flag){
412         case CP_MEASUREMENT_FLAG_PEDAL_POWER_BALANCE_PRESENT:
413             return 1;
414         case CP_MEASUREMENT_FLAG_WHEEL_REVOLUTION_DATA_PRESENT:
415             return 6;
416         case CP_MEASUREMENT_FLAG_CRANK_REVOLUTION_DATA_PRESENT:
417         case CP_MEASUREMENT_FLAG_EXTREME_FORCE_MAGNITUDES_PRESENT:
418         case CP_MEASUREMENT_FLAG_EXTREME_TORQUE_MAGNITUDES_PRESENT:
419             return 4;
420         case CP_MEASUREMENT_FLAG_EXTREME_ANGLES_PRESENT:
421             return 3;
422         case CP_MEASUREMENT_FLAG_ACCUMULATED_TORQUE_PRESENT:
423         case CP_MEASUREMENT_FLAG_TOP_DEAD_SPOT_ANGLE_PRESENT:
424         case CP_MEASUREMENT_FLAG_BOTTOM_DEAD_SPOT_ANGLE_PRESENT:
425         case CP_MEASUREMENT_FLAG_ACCUMULATED_ENERGY_PRESENT:
426             return 2;
427         default:
428             return 0;
429     }
430 }
431 
432 static int cycling_power_store_measurement_flag_value(cycling_power_t * instance, cycling_power_measurement_flag_t flag, uint8_t * value){
433     if (!instance) return 0;
434 
435     int pos = 0;
436     switch (flag){
437         case CP_MEASUREMENT_FLAG_PEDAL_POWER_BALANCE_PRESENT:
438             value[pos++] = instance->pedal_power_balance_percentage;
439             break;
440         case CP_MEASUREMENT_FLAG_ACCUMULATED_TORQUE_PRESENT:
441             little_endian_store_16(value, pos, instance->accumulated_torque_m);
442             pos += 2;
443             break;
444         case CP_MEASUREMENT_FLAG_WHEEL_REVOLUTION_DATA_PRESENT:
445             little_endian_store_32(value, pos, instance->cumulative_wheel_revolutions);
446             pos += 4;
447             little_endian_store_16(value, pos, instance->last_wheel_event_time_s);
448             pos += 2;
449             break;
450         case CP_MEASUREMENT_FLAG_CRANK_REVOLUTION_DATA_PRESENT:
451             little_endian_store_16(value, pos, instance->cumulative_crank_revolutions);
452             pos += 2;
453             little_endian_store_16(value, pos, instance->last_crank_event_time_s);
454             pos += 2;
455             break;
456         case CP_MEASUREMENT_FLAG_EXTREME_FORCE_MAGNITUDES_PRESENT:
457             little_endian_store_16(value, pos, (uint16_t)instance->maximum_force_magnitude_newton);
458             pos += 2;
459             little_endian_store_16(value, pos, (uint16_t)instance->minimum_force_magnitude_newton);
460             pos += 2;
461             break;
462         case CP_MEASUREMENT_FLAG_EXTREME_TORQUE_MAGNITUDES_PRESENT:
463             little_endian_store_16(value, pos, (uint16_t)instance->maximum_torque_magnitude_newton_m);
464             pos += 2;
465             little_endian_store_16(value, pos, (uint16_t)instance->minimum_torque_magnitude_newton_m);
466             pos += 2;
467             break;
468         case CP_MEASUREMENT_FLAG_EXTREME_ANGLES_PRESENT:
469             little_endian_store_24(value, pos, (instance->maximum_angle_deg << 12) | instance->minimum_angle_deg);
470             pos += 3;
471             break;
472         case CP_MEASUREMENT_FLAG_TOP_DEAD_SPOT_ANGLE_PRESENT:
473             little_endian_store_16(value, pos, (uint16_t)instance->top_dead_spot_angle_deg);
474             pos += 2;
475             break;
476         case CP_MEASUREMENT_FLAG_BOTTOM_DEAD_SPOT_ANGLE_PRESENT:
477             little_endian_store_16(value, pos, (uint16_t)instance->bottom_dead_spot_angle_deg);
478             pos += 2;
479             break;
480         case CP_MEASUREMENT_FLAG_ACCUMULATED_ENERGY_PRESENT:
481             little_endian_store_16(value, pos, (uint16_t)instance->accumulated_energy_kJ);
482             pos += 2;
483             break;
484         default:
485             break;
486     }
487     return pos;
488 }
489 
490 
491 static int cycling_power_store_measurement(cycling_power_t * instance, uint8_t * value, uint16_t max_value_size){
492     if (max_value_size < 4u) return 0u;
493     if (!instance) return 0;
494 
495     uint16_t measurement_flags = cycling_power_service_get_measurement_flags(instance);
496     int pos = 0;
497     little_endian_store_16(value, 0, measurement_flags);
498     pos += 2;
499     little_endian_store_16(value, 2, instance->instantaneous_power_watt);
500     pos += 2;
501     int flag_index;
502     uint16_t bytes_left = max_value_size - pos;
503     for (flag_index = 0; flag_index < CP_MEASUREMENT_FLAG_RESERVED; flag_index++){
504         if ((measurement_flags & (1u << flag_index)) == 0u) continue;
505         cycling_power_measurement_flag_t flag = (cycling_power_measurement_flag_t) flag_index;
506         uint16_t value_size = cycling_power_measurement_flag_value_size(flag);
507         if (value_size > bytes_left ) return pos;
508         cycling_power_store_measurement_flag_value(instance, flag, &value[pos]);
509         pos += value_size;
510         bytes_left -= value_size;
511     }
512     return pos;
513 }
514 
515 int cycling_power_get_measurement_adv(uint16_t adv_interval, uint8_t * broadcast_adv, uint16_t max_value_size){
516     if (max_value_size < 12u) return 0u;
517     cycling_power_t * instance =  &cycling_power;
518     int pos = 0;
519     // adv flags
520     broadcast_adv[pos++] = 2;
521     broadcast_adv[pos++] = BLUETOOTH_DATA_TYPE_FLAGS;
522     broadcast_adv[pos++] = 0x4;
523 
524     // adv interval
525     broadcast_adv[pos++] = 3;
526     broadcast_adv[pos++] = BLUETOOTH_DATA_TYPE_ADVERTISING_INTERVAL;
527     little_endian_store_16(broadcast_adv, pos, adv_interval);
528     pos += 2;
529     //
530     int value_len = cycling_power_store_measurement(instance, &broadcast_adv[pos+4], CYCLING_POWER_MAX_BROACAST_MSG_SIZE - (pos + 4));
531     broadcast_adv[pos++] = 3 + value_len;
532     broadcast_adv[pos++] = BLUETOOTH_DATA_TYPE_SERVICE_DATA_16_BIT_UUID;
533     little_endian_store_16(broadcast_adv, pos, ORG_BLUETOOTH_SERVICE_CYCLING_POWER);
534     pos += 2;
535     // value data already in place cycling_power_get_measurement
536     pos += value_len;
537     // set ADV_NONCONN_IND
538     return pos;
539 }
540 
541 static void cycling_power_service_broadcast_can_send_now(void * context){
542     cycling_power_t * instance = (cycling_power_t *) context;
543     if (!instance){
544         log_error("cycling_power_service_broadcast_can_send_now: instance is null");
545         return;
546     }
547     uint8_t value[CYCLING_POWER_MAX_BROACAST_MSG_SIZE];
548     int pos = cycling_power_store_measurement(instance, &value[0], sizeof(value));
549     att_server_notify(instance->con_handle, instance->measurement_value_handle, &value[0], pos);
550 }
551 
552 static void cycling_power_service_measurement_can_send_now(void * context){
553     cycling_power_t * instance = (cycling_power_t *) context;
554     if (!instance){
555         log_error("cycling_power_service_measurement_can_send_now: instance is null");
556         return;
557     }
558     uint8_t value[40];
559     int pos = cycling_power_store_measurement(instance, &value[0], sizeof(value));
560     att_server_notify(instance->con_handle, instance->measurement_value_handle, &value[0], pos);
561 }
562 
563 static void cycling_power_service_response_can_send_now(void * context){
564     cycling_power_t * instance = (cycling_power_t *) context;
565     if (!instance){
566         log_error("cycling_power_service_response_can_send_now: instance is null");
567         return;
568     }
569 
570     if (instance->response_value == CP_RESPONSE_VALUE_W4_VALUE_AVAILABLE){
571         log_error("cycling_power_service_response_can_send_now: CP_RESPONSE_VALUE_W4_VALUE_AVAILABLE");
572         return;
573     }
574 
575     // if (instance->w4_indication_complete){
576     //     printf("cycling_power_service_response_can_send_now: w4_indication_complete\n");
577     //     return;
578     // }
579 
580     // use preprocessor instead of btstack_max to get compile-time constant
581 #if (CP_SENSOR_LOCATION_RESERVED > (CYCLING_POWER_MANUFACTURER_SPECIFIC_DATA_MAX_SIZE + 5))
582     #define MAX_RESPONSE_PAYLOAD CP_SENSOR_LOCATION_RESERVED
583 #else
584     #define MAX_RESPONSE_PAYLOAD (CYCLING_POWER_MANUFACTURER_SPECIFIC_DATA_MAX_SIZE + 5)
585 #endif
586 
587     uint8_t value[3 + MAX_RESPONSE_PAYLOAD];
588     int pos = 0;
589     value[pos++] = CP_OPCODE_RESPONSE_CODE;
590     value[pos++] = instance->request_opcode;
591     value[pos++] = instance->response_value;
592     if (instance->response_value == CP_RESPONSE_VALUE_SUCCESS){
593         switch (instance->request_opcode){
594             case CP_OPCODE_REQUEST_SUPPORTED_SENSOR_LOCATIONS:{
595                 int i;
596                 for (i=0; i<instance->num_supported_sensor_locations; i++){
597                     value[pos++] = instance->supported_sensor_locations[i];
598                 }
599                 break;
600             }
601             case CP_OPCODE_REQUEST_CRANK_LENGTH:
602                 little_endian_store_16(value, pos, instance->crank_length_mm);
603                 pos += 2;
604                 break;
605             case CP_OPCODE_REQUEST_CHAIN_LENGTH:
606                 little_endian_store_16(value, pos, instance->chain_length_mm);
607                 pos += 2;
608                 break;
609             case CP_OPCODE_REQUEST_CHAIN_WEIGHT:
610                 little_endian_store_16(value, pos, instance->chain_weight_g);
611                 pos += 2;
612                 break;
613             case CP_OPCODE_REQUEST_SPAN_LENGTH:
614                 little_endian_store_16(value, pos, instance->span_length_mm);
615                 pos += 2;
616                 break;
617             case CP_OPCODE_REQUEST_FACTORY_CALIBRATION_DATE:
618                 little_endian_store_16(value, pos, instance->factory_calibration_date.year);
619                 pos += 2;
620                 value[pos++] = instance->factory_calibration_date.month;
621                 value[pos++] = instance->factory_calibration_date.day;
622                 value[pos++] = instance->factory_calibration_date.hours;
623                 value[pos++] = instance->factory_calibration_date.minutes;
624                 value[pos++] = instance->factory_calibration_date.seconds;
625                 break;
626             case CP_OPCODE_REQUEST_SAMPLING_RATE:
627                 value[pos++] = instance->sampling_rate_hz;
628                 break;
629             case CP_OPCODE_START_OFFSET_COMPENSATION:
630             case CP_OPCODE_START_ENHANCED_OFFSET_COMPENSATION:{
631                 uint16_t calibrated_value = 0xffff;
632                 if (has_feature(CP_FEATURE_FLAG_EXTREME_MAGNITUDES_SUPPORTED)){
633                     if (has_feature(CP_FEATURE_FLAG_SENSOR_MEASUREMENT_CONTEXT) == CP_SENSOR_MEASUREMENT_CONTEXT_FORCE) {
634                         calibrated_value = instance->current_force_magnitude_newton;
635                     } else if (has_feature(CP_FEATURE_FLAG_SENSOR_MEASUREMENT_CONTEXT) == CP_SENSOR_MEASUREMENT_CONTEXT_TORQUE){
636                         calibrated_value = instance->current_torque_magnitude_newton_m;
637                     }
638                 }
639 
640                 if (calibrated_value == CP_CALIBRATION_STATUS_INCORRECT_CALIBRATION_POSITION){
641                      value[pos++] = calibrated_value;
642                      // do not include manufacturer ID and data
643                      break;
644                 } else if (calibrated_value == CP_CALIBRATION_STATUS_MANUFACTURER_SPECIFIC_ERROR_FOLLOWS){
645                     value[pos++] = calibrated_value;
646                 } else {
647                     little_endian_store_16(value, pos, calibrated_value);
648                     pos += 2;
649 
650                 }
651 
652                 if (instance->request_opcode == CP_OPCODE_START_OFFSET_COMPENSATION) break;
653                 little_endian_store_16(value, pos, instance->manufacturer_company_id);
654                 pos += 2;
655                 int data_len = (instance->num_manufacturer_specific_data < CYCLING_POWER_MANUFACTURER_SPECIFIC_DATA_MAX_SIZE) ? instance->num_manufacturer_specific_data : (CYCLING_POWER_MANUFACTURER_SPECIFIC_DATA_MAX_SIZE - 1);
656                 value[pos++] = data_len;
657                 (void)memcpy(&value[pos],
658                              instance->manufacturer_specific_data, data_len);
659                 pos += data_len;
660                 value[pos++] = 0;
661                 break;
662             }
663             case CP_OPCODE_MASK_CYCLING_POWER_MEASUREMENT_CHARACTERISTIC_CONTENT:
664                 break;
665             default:
666                 break;
667         }
668     }
669     uint8_t status = att_server_indicate(instance->con_handle, instance->control_point_value_handle, &value[0], pos);
670     if (status == ERROR_CODE_SUCCESS){
671         instance->w4_indication_complete = 1;
672         // printf("cycling_power_service_response_can_send_now: set w4_indication_complete\n");
673         // printf("can_send_now set opcode to CP_OPCODE_IDLE\n");
674         instance->request_opcode = CP_OPCODE_IDLE;
675     } else {
676         log_error("can_send_now failed 0x%2x", status);
677     }
678 }
679 
680 static int cycling_power_service_write_callback(hci_con_handle_t con_handle, uint16_t attribute_handle, uint16_t transaction_mode, uint16_t offset, uint8_t *buffer, uint16_t buffer_size){
681     UNUSED(con_handle);
682     UNUSED(transaction_mode);
683     UNUSED(offset);
684     UNUSED(buffer_size);
685     int i;
686     cycling_power_sensor_location_t location;
687     cycling_power_t * instance = &cycling_power;
688 
689     // printf("cycling_power_service_write_callback: attr handle 0x%02x\n", attribute_handle);
690     if (attribute_handle == instance->measurement_client_configuration_descriptor_handle){
691         if (buffer_size < 2u){
692             return ATT_ERROR_INVALID_OFFSET;
693         }
694         instance->measurement_client_configuration_descriptor_notify = little_endian_read_16(buffer, 0);
695         instance->con_handle = con_handle;
696         log_info("cycling_power_service_write_callback: measurement enabled %d", instance->measurement_client_configuration_descriptor_notify);
697         return 0;
698     }
699 
700     if (attribute_handle == instance->measurement_server_configuration_descriptor_handle){
701         if (buffer_size < 2u){
702             return ATT_ERROR_INVALID_OFFSET;
703         }
704         instance->measurement_server_configuration_descriptor_broadcast = little_endian_read_16(buffer, 0);
705         instance->con_handle = con_handle;
706         uint8_t event[5];
707         int index = 0;
708         event[index++] = HCI_EVENT_GATTSERVICE_META;
709         event[index++] = sizeof(event) - 2u;
710 
711         if (instance->measurement_server_configuration_descriptor_broadcast){
712             event[index++] = GATTSERVICE_SUBEVENT_CYCLING_POWER_BROADCAST_START;
713             log_info("cycling_power_service_write_callback: start broadcast");
714         } else {
715             event[index++] = GATTSERVICE_SUBEVENT_CYCLING_POWER_BROADCAST_STOP;
716             log_info("cycling_power_service_write_callback: stop broadcast");
717         }
718         little_endian_store_16(event, index, con_handle);
719         index += 2;
720         (*instance->calibration_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
721         return 0;
722     }
723 
724     if (attribute_handle == instance->vector_client_configuration_descriptor_handle){
725         if (buffer_size < 2u){
726             return ATT_ERROR_INVALID_OFFSET;
727         }
728         instance->con_handle = con_handle;
729 
730 #ifdef ENABLE_ATT_DELAYED_RESPONSE
731         switch (instance->con_interval_status){
732             case CP_CONNECTION_INTERVAL_STATUS_REJECTED:
733                 return CYCLING_POWER_ERROR_CODE_INAPPROPRIATE_CONNECTION_PARAMETERS;
734 
735             case CP_CONNECTION_INTERVAL_STATUS_ACCEPTED:
736             case CP_CONNECTION_INTERVAL_STATUS_RECEIVED:
737                 if ((instance->con_interval > instance->con_interval_max) || (instance->con_interval < instance->con_interval_min)){
738                     instance->con_interval_status = CP_CONNECTION_INTERVAL_STATUS_W4_L2CAP_RESPONSE;
739                     gap_request_connection_parameter_update(instance->con_handle, instance->con_interval_min, instance->con_interval_max, 4, 100);    // 15 ms, 4, 1s
740                     return ATT_ERROR_WRITE_RESPONSE_PENDING;
741                 }
742                 instance->vector_client_configuration_descriptor_notify = little_endian_read_16(buffer, 0);
743                 return 0;
744             default:
745                 return ATT_ERROR_WRITE_RESPONSE_PENDING;
746 
747         }
748 #endif
749     }
750 
751     if (attribute_handle == instance->control_point_client_configuration_descriptor_handle){
752         if (buffer_size < 2u){
753             return ATT_ERROR_INVALID_OFFSET;
754         }
755         instance->control_point_client_configuration_descriptor_indicate = little_endian_read_16(buffer, 0);
756         instance->con_handle = con_handle;
757         log_info("cycling_power_service_write_callback: indication enabled %d", instance->control_point_client_configuration_descriptor_indicate);
758         return 0;
759     }
760 
761     if (attribute_handle == instance->feature_value_handle){
762         if (buffer_size < 4u){
763             return ATT_ERROR_INVALID_OFFSET;
764         }
765         instance->feature_flags = little_endian_read_32(buffer, 0);
766         return 0;
767     }
768 
769     if (attribute_handle == instance->control_point_value_handle){
770         if (instance->control_point_client_configuration_descriptor_indicate == 0u) return CYCLING_POWER_ERROR_CODE_CCC_DESCRIPTOR_IMPROPERLY_CONFIGURED;
771         if (instance->w4_indication_complete != 0u){
772             return CYCLING_POWER_ERROR_CODE_PROCEDURE_ALREADY_IN_PROGRESS;
773         }
774         int pos = 0;
775         instance->request_opcode = (cycling_power_opcode_t) buffer[pos++];
776         instance->response_value = CP_RESPONSE_VALUE_OP_CODE_NOT_SUPPORTED;
777 
778         switch (instance->request_opcode){
779             case CP_OPCODE_SET_CUMULATIVE_VALUE:
780                 if (!has_feature(CP_FEATURE_FLAG_WHEEL_REVOLUTION_DATA_SUPPORTED)) break;
781                 instance->cumulative_wheel_revolutions = little_endian_read_32(buffer, pos);
782                 instance->response_value = CP_RESPONSE_VALUE_SUCCESS;
783                 break;
784 
785             case CP_OPCODE_REQUEST_SUPPORTED_SENSOR_LOCATIONS:
786                 if (!has_feature(CP_FEATURE_FLAG_MULTIPLE_SENSOR_LOCATIONS_SUPPORTED)) break;
787                 instance->response_value = CP_RESPONSE_VALUE_SUCCESS;
788                 break;
789 
790             case CP_OPCODE_UPDATE_SENSOR_LOCATION:
791                 if (!has_feature(CP_FEATURE_FLAG_MULTIPLE_SENSOR_LOCATIONS_SUPPORTED)) break;
792                 location = (cycling_power_sensor_location_t) buffer[pos];
793                 instance->response_value = CP_RESPONSE_VALUE_INVALID_PARAMETER;
794                 for (i=0; i<instance->num_supported_sensor_locations; i++){
795                     if (instance->supported_sensor_locations[i] == location){
796                         instance->sensor_location = location;
797                         instance->response_value = CP_RESPONSE_VALUE_SUCCESS;
798                         break;
799                     }
800                 }
801                 break;
802 
803             case CP_OPCODE_REQUEST_CRANK_LENGTH:
804                 if (!has_feature(CP_FEATURE_FLAG_CRANK_LENGTH_ADJUSTMENT_SUPPORTED)) break;
805                 instance->response_value = CP_RESPONSE_VALUE_SUCCESS;
806                 break;
807             case CP_OPCODE_SET_CRANK_LENGTH:
808                 if (!has_feature(CP_FEATURE_FLAG_CRANK_LENGTH_ADJUSTMENT_SUPPORTED)) break;
809                 instance->crank_length_mm = little_endian_read_16(buffer, pos);
810                 instance->response_value = CP_RESPONSE_VALUE_SUCCESS;
811                 break;
812 
813             case CP_OPCODE_REQUEST_CHAIN_LENGTH:
814                 if (!has_feature(CP_FEATURE_FLAG_CHAIN_LENGTH_ADJUSTMENT_SUPPORTED)) break;
815                 instance->response_value = CP_RESPONSE_VALUE_SUCCESS;
816                 break;
817             case CP_OPCODE_SET_CHAIN_LENGTH:
818                 if (!has_feature(CP_FEATURE_FLAG_CHAIN_LENGTH_ADJUSTMENT_SUPPORTED)) break;
819                 instance->chain_length_mm = little_endian_read_16(buffer, pos);
820                 instance->response_value = CP_RESPONSE_VALUE_SUCCESS;
821                 break;
822 
823             case CP_OPCODE_REQUEST_CHAIN_WEIGHT:
824                 if (!has_feature(CP_FEATURE_FLAG_CHAIN_WEIGHT_ADJUSTMENT_SUPPORTED)) break;
825                 instance->response_value = CP_RESPONSE_VALUE_SUCCESS;
826                 break;
827             case CP_OPCODE_SET_CHAIN_WEIGHT:
828                 if (!has_feature(CP_FEATURE_FLAG_CHAIN_WEIGHT_ADJUSTMENT_SUPPORTED)) break;
829                 instance->chain_weight_g = little_endian_read_16(buffer, pos);
830                 instance->response_value = CP_RESPONSE_VALUE_SUCCESS;
831                 break;
832 
833             case CP_OPCODE_REQUEST_SPAN_LENGTH:
834                 if (!has_feature(CP_FEATURE_FLAG_SPAN_LENGTH_ADJUSTMENT_SUPPORTED)) break;
835                 instance->response_value = CP_RESPONSE_VALUE_SUCCESS;
836                 break;
837             case CP_OPCODE_SET_SPAN_LENGTH:
838                 if (!has_feature(CP_FEATURE_FLAG_SPAN_LENGTH_ADJUSTMENT_SUPPORTED)) break;
839                 instance->span_length_mm = little_endian_read_16(buffer, pos);
840                 instance->response_value = CP_RESPONSE_VALUE_SUCCESS;
841                 break;
842 
843             case CP_OPCODE_REQUEST_FACTORY_CALIBRATION_DATE:
844                 if (!has_feature(CP_FEATURE_FLAG_FACTORY_CALIBRATION_DATE_SUPPORTED)) break;
845                 instance->response_value = CP_RESPONSE_VALUE_SUCCESS;
846                 break;
847 
848             case CP_OPCODE_REQUEST_SAMPLING_RATE:
849                 if (!instance->vector_value_handle) break;
850                 instance->response_value = CP_RESPONSE_VALUE_SUCCESS;
851                 break;
852 
853             case CP_OPCODE_START_OFFSET_COMPENSATION:
854             case CP_OPCODE_START_ENHANCED_OFFSET_COMPENSATION:
855                 if (!has_feature(CP_FEATURE_FLAG_OFFSET_COMPENSATION_SUPPORTED)){
856                     instance->response_value = CP_RESPONSE_VALUE_INVALID_PARAMETER;
857                     break;
858                 }
859                 if (has_feature(CP_FEATURE_FLAG_EXTREME_MAGNITUDES_SUPPORTED) &&
860                         ((has_feature(CP_FEATURE_FLAG_SENSOR_MEASUREMENT_CONTEXT) == CP_SENSOR_MEASUREMENT_CONTEXT_FORCE) ||
861                          (has_feature(CP_FEATURE_FLAG_SENSOR_MEASUREMENT_CONTEXT) == CP_SENSOR_MEASUREMENT_CONTEXT_TORQUE))
862                 ){
863                     // printf("start offset compensation procedure, enhanced %d\n", (instance->request_opcode == CP_OPCODE_START_ENHANCED_OFFSET_COMPENSATION));
864                     uint8_t event[7];
865                     int index = 0;
866                     event[index++] = HCI_EVENT_GATTSERVICE_META;
867                     event[index++] = sizeof(event) - 2u;
868                     event[index++] = GATTSERVICE_SUBEVENT_CYCLING_POWER_START_CALIBRATION;
869                     little_endian_store_16(event, index, con_handle);
870                     index += 2;
871                     event[index++] = has_feature(CP_FEATURE_FLAG_SENSOR_MEASUREMENT_CONTEXT) == CP_SENSOR_MEASUREMENT_CONTEXT_TORQUE;
872                     event[index++] = (instance->request_opcode == CP_OPCODE_START_ENHANCED_OFFSET_COMPENSATION);
873                     instance->response_value = CP_RESPONSE_VALUE_W4_VALUE_AVAILABLE;
874                     (*instance->calibration_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
875                     return 0;
876                 }
877                 instance->current_force_magnitude_newton = 0xffff;
878                 instance->current_torque_magnitude_newton_m = 0xffff;
879                 break;
880 
881             case CP_OPCODE_MASK_CYCLING_POWER_MEASUREMENT_CHARACTERISTIC_CONTENT:{
882                 if (!has_feature(CP_FEATURE_FLAG_CYCLING_POWER_MEASUREMENT_CHARACTERISTIC_CONTENT_MASKING_SUPPORTED)) break;
883                 uint16_t mask_bitmap = little_endian_read_16(buffer, pos);
884                 uint16_t masked_measurement_flags = instance->default_measurement_flags;
885                 uint16_t index = 0;
886 
887                 for (i = 0; i < CP_MASK_BIT_RESERVED; i++){
888                     uint8_t clear_bit = (mask_bitmap & (1u << i)) ? 1u : 0u;
889 
890                     masked_measurement_flags &= ~(clear_bit << index);
891                     index++;
892                     // following measurement flags have additional flag
893                     switch ((cycling_power_mask_bit_t)i){
894                         case CP_MASK_BIT_PEDAL_POWER_BALANCE:
895                         case CP_MASK_BIT_ACCUMULATED_TORQUE:
896                         case CP_MASK_BIT_EXTREME_MAGNITUDES:
897                             masked_measurement_flags &= ~(clear_bit << index);
898                             index++;
899                             break;
900                         default:
901                             break;
902                     }
903                 }
904                 instance->masked_measurement_flags = masked_measurement_flags;
905                 instance->response_value = CP_RESPONSE_VALUE_SUCCESS;
906                 break;
907             }
908             default:
909                 break;
910         }
911 
912         if (instance->control_point_client_configuration_descriptor_indicate){
913             instance->control_point_indicate_callback.callback = &cycling_power_service_response_can_send_now;
914             instance->control_point_indicate_callback.context  = (void*) instance;
915             att_server_register_can_send_now_callback(&instance->control_point_indicate_callback, instance->con_handle);
916         }
917         return 0;
918     }
919     return 0;
920 }
921 
922 static void packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
923     UNUSED(channel);
924     UNUSED(size);
925     cycling_power_t * instance = &cycling_power;
926     uint8_t event_type = hci_event_packet_get_type(packet);
927     uint16_t con_handle;
928 
929     if (packet_type != HCI_EVENT_PACKET) return;
930     switch (event_type){
931         case HCI_EVENT_LE_META:
932             switch (hci_event_le_meta_get_subevent_code(packet)){
933                 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE:
934                     instance->con_handle = hci_subevent_le_connection_complete_get_connection_handle(packet);
935                     // print connection parameters (without using float operations)
936                     instance->con_interval = hci_subevent_le_connection_complete_get_conn_interval(packet);
937                     // printf("Initial Connection Interval: %u, %u.%02u ms\n", instance->con_interval, instance->con_interval * 125 / 100, 25 * (instance->con_interval & 3));
938                     // printf("Initial Connection Latency: %u\n", hci_subevent_le_connection_complete_get_conn_latency(packet));
939                     instance->con_interval_status = CP_CONNECTION_INTERVAL_STATUS_RECEIVED;
940                     break;
941 
942 #ifdef ENABLE_ATT_DELAYED_RESPONSE
943                 case HCI_SUBEVENT_LE_CONNECTION_UPDATE_COMPLETE:
944                     if (instance->con_interval_status != CP_CONNECTION_INTERVAL_STATUS_W4_UPDATE) return;
945 
946                     if ((instance->con_interval > instance->con_interval_max) || (instance->con_interval < instance->con_interval_min)){
947                         instance->con_interval = hci_subevent_le_connection_update_complete_get_conn_interval(packet);
948                         instance->con_interval_status = CP_CONNECTION_INTERVAL_STATUS_ACCEPTED;
949                     } else {
950                         instance->con_interval_status = CP_CONNECTION_INTERVAL_STATUS_REJECTED;
951                     }
952                     att_server_response_ready(l2cap_event_connection_parameter_update_response_get_handle(packet));
953                     break;
954 #endif
955                 default:
956                     break;
957             }
958             break;
959 
960 #ifdef ENABLE_ATT_DELAYED_RESPONSE
961         case L2CAP_EVENT_CONNECTION_PARAMETER_UPDATE_RESPONSE:
962             if (instance->con_interval_status != CP_CONNECTION_INTERVAL_STATUS_W4_L2CAP_RESPONSE) return;
963 
964             if (l2cap_event_connection_parameter_update_response_get_result(packet) == ERROR_CODE_SUCCESS){
965                 instance->con_interval_status = CP_CONNECTION_INTERVAL_STATUS_W4_UPDATE;
966             } else {
967                 instance->con_interval_status = CP_CONNECTION_INTERVAL_STATUS_REJECTED;
968                 att_server_response_ready(l2cap_event_connection_parameter_update_response_get_handle(packet));
969             }
970             break;
971 #endif
972 
973         case HCI_EVENT_DISCONNECTION_COMPLETE:{
974             if (!instance) return;
975             con_handle = hci_event_disconnection_complete_get_connection_handle(packet);
976             if (con_handle == HCI_CON_HANDLE_INVALID) return;
977 
978             instance->masked_measurement_flags = CYCLING_POWER_MEASUREMENT_FLAGS_CLEARED;
979             instance->w4_indication_complete = 0;
980 
981             uint8_t event[5];
982             int index = 0;
983             event[index++] = HCI_EVENT_GATTSERVICE_META;
984             event[index++] = sizeof(event) - 2u;
985 
986             event[index++] = GATTSERVICE_SUBEVENT_CYCLING_POWER_BROADCAST_STOP;
987             little_endian_store_16(event, index, con_handle);
988             index += 2;
989             (*instance->calibration_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
990 
991             break;
992         }
993         case ATT_EVENT_HANDLE_VALUE_INDICATION_COMPLETE:
994             instance->w4_indication_complete = 0;
995             break;
996         default:
997             break;
998      }
999 }
1000 
1001 void cycling_power_service_server_init(uint32_t feature_flags,
1002     cycling_power_pedal_power_balance_reference_t reference, cycling_power_torque_source_t torque_source,
1003     cycling_power_sensor_location_t * supported_sensor_locations, uint16_t num_supported_sensor_locations,
1004     cycling_power_sensor_location_t   current_sensor_location){
1005 
1006     cycling_power_t * instance = &cycling_power;
1007     // TODO: remove hardcoded initialization
1008     instance->con_interval_min = 6;
1009     instance->con_interval_max = 6;
1010     instance->con_interval_status = CP_CONNECTION_INTERVAL_STATUS_NONE;
1011     instance->w4_indication_complete = 0;
1012     hci_event_callback_registration.callback = &packet_handler;
1013     hci_add_event_handler(&hci_event_callback_registration);
1014     l2cap_register_packet_handler(&packet_handler);
1015 
1016     instance->sensor_location = current_sensor_location;
1017     instance->num_supported_sensor_locations = 0;
1018     if (supported_sensor_locations != NULL){
1019         instance->num_supported_sensor_locations = num_supported_sensor_locations;
1020         instance->supported_sensor_locations = supported_sensor_locations;
1021     }
1022 
1023     instance->feature_flags = feature_flags;
1024     instance->default_measurement_flags = CYCLING_POWER_MEASUREMENT_FLAGS_CLEARED;
1025     instance->masked_measurement_flags  = CYCLING_POWER_MEASUREMENT_FLAGS_CLEARED;
1026     instance->pedal_power_balance_reference = reference;
1027     instance->torque_source = torque_source;
1028 
1029     // get service handle range
1030     uint16_t start_handle = 0;
1031     uint16_t end_handle   = 0xffff;
1032     int service_found = gatt_server_get_get_handle_range_for_service_with_uuid16(ORG_BLUETOOTH_SERVICE_CYCLING_POWER, &start_handle, &end_handle);
1033     btstack_assert(service_found != 0);
1034 	UNUSED(service_found);
1035 
1036     // get CP Mesurement characteristic value handle and client configuration handle
1037     instance->measurement_value_handle = gatt_server_get_value_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_CYCLING_POWER_MEASUREMENT);
1038     instance->measurement_client_configuration_descriptor_handle = gatt_server_get_client_configuration_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_CYCLING_POWER_MEASUREMENT);
1039     instance->measurement_server_configuration_descriptor_handle = gatt_server_get_server_configuration_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_CYCLING_POWER_MEASUREMENT);
1040 
1041     // get CP Feature characteristic value handle and client configuration handle
1042     instance->feature_value_handle = gatt_server_get_value_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_CYCLING_POWER_FEATURE);
1043     // get CP Sensor Location characteristic value handle and client configuration handle
1044     instance->sensor_location_value_handle = gatt_server_get_value_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_SENSOR_LOCATION);
1045 
1046     // get CP Vector characteristic value handle and client configuration handle
1047     instance->vector_value_handle = gatt_server_get_value_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_CYCLING_POWER_VECTOR);
1048     instance->vector_client_configuration_descriptor_handle = gatt_server_get_client_configuration_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_CYCLING_POWER_VECTOR);
1049 
1050     // get Body Sensor Location characteristic value handle and client configuration handle
1051     instance->sensor_location_value_handle = gatt_server_get_value_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_SENSOR_LOCATION);
1052 
1053     // get SP Control Point characteristic value handle and client configuration handle
1054     instance->control_point_value_handle = gatt_server_get_value_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_CYCLING_POWER_CONTROL_POINT);
1055     instance->control_point_client_configuration_descriptor_handle = gatt_server_get_client_configuration_handle_for_characteristic_with_uuid16(start_handle, end_handle, ORG_BLUETOOTH_CHARACTERISTIC_CYCLING_POWER_CONTROL_POINT);
1056 
1057     log_info("Measurement     value handle 0x%02x", instance->measurement_value_handle);
1058     log_info("M. Client Cfg   value handle 0x%02x", instance->measurement_client_configuration_descriptor_handle);
1059     log_info("M. Server Cfg   value handle 0x%02x", instance->measurement_server_configuration_descriptor_handle);
1060 
1061     log_info("Feature         value handle 0x%02x", instance->feature_value_handle);
1062     log_info("Sensor location value handle 0x%02x", instance->sensor_location_value_handle);
1063 
1064     log_info("Vector          value handle 0x%02x", instance->vector_value_handle);
1065     log_info("Vector Cfg.     value handle 0x%02x", instance->vector_client_configuration_descriptor_handle);
1066 
1067     log_info("Control Point   value handle 0x%02x", instance->control_point_value_handle);
1068     log_info("Control P. Cfg. value handle 0x%02x", instance->control_point_client_configuration_descriptor_handle);
1069 
1070     cycling_power_service.start_handle   = start_handle;
1071     cycling_power_service.end_handle     = end_handle;
1072     cycling_power_service.read_callback  = &cycling_power_service_read_callback;
1073     cycling_power_service.write_callback = &cycling_power_service_write_callback;
1074     cycling_power_service.packet_handler = &packet_handler;
1075     att_server_register_service_handler(&cycling_power_service);
1076 }
1077 
1078 
1079 void cycling_power_service_server_add_torque(int16_t torque_m){
1080     cycling_power_t * instance = &cycling_power;
1081     instance->accumulated_torque_m += torque_m;
1082 }
1083 
1084 void cycling_power_service_server_add_wheel_revolution(int32_t wheel_revolution, uint16_t wheel_event_time_s){
1085     cycling_power_t * instance = &cycling_power;
1086     instance->last_wheel_event_time_s = wheel_event_time_s;
1087     if (wheel_revolution < 0){
1088         if (instance->cumulative_wheel_revolutions > -wheel_revolution){
1089             instance->cumulative_wheel_revolutions += wheel_revolution;
1090         } else {
1091             instance->cumulative_wheel_revolutions = 0;
1092         }
1093     } else {
1094         if (instance->cumulative_wheel_revolutions < (0xffffffff - wheel_revolution)){
1095             instance->cumulative_wheel_revolutions += wheel_revolution;
1096         } else {
1097             instance->cumulative_wheel_revolutions = 0xffffffff;
1098         }
1099     }
1100 }
1101 
1102 void cycling_power_service_server_add_crank_revolution(uint16_t crank_revolution, uint16_t crank_event_time_s){
1103     cycling_power_t * instance = &cycling_power;
1104     instance->last_crank_event_time_s = crank_event_time_s;
1105     instance->cumulative_crank_revolutions += crank_revolution;
1106 }
1107 
1108 void cycling_power_service_add_energy(uint16_t energy_kJ){
1109     cycling_power_t * instance = &cycling_power;
1110     if (instance->accumulated_energy_kJ <= (0xffffu - energy_kJ)){
1111         instance->accumulated_energy_kJ += energy_kJ;
1112     } else {
1113         instance->accumulated_energy_kJ = 0xffff;
1114     }
1115     // printf("energy %d\n", instance->accumulated_energy_kJ);
1116 }
1117 
1118 void cycling_power_service_server_set_instantaneous_power(int16_t instantaneous_power_watt){
1119     cycling_power_t * instance = &cycling_power;
1120     instance->instantaneous_power_watt = instantaneous_power_watt;
1121 }
1122 
1123 void cycling_power_service_server_set_pedal_power_balance(uint8_t pedal_power_balance_percentage){
1124     cycling_power_t * instance = &cycling_power;
1125     instance->pedal_power_balance_percentage = pedal_power_balance_percentage;
1126 }
1127 
1128 void cycling_power_service_server_set_force_magnitude_values(int force_magnitude_count, int16_t * force_magnitude_newton_array){
1129     cycling_power_t * instance = &cycling_power;
1130     instance->force_magnitude_count = force_magnitude_count;
1131     instance->vector_instantaneous_force_magnitude_newton_array = force_magnitude_newton_array;
1132 }
1133 
1134 void cycling_power_service_server_set_torque_magnitude_values(int torque_magnitude_count, int16_t * torque_magnitude_newton_array){
1135     cycling_power_t * instance = &cycling_power;
1136     instance->torque_magnitude_count = torque_magnitude_count;
1137     instance->vector_instantaneous_torque_magnitude_newton_per_m_array = torque_magnitude_newton_array;
1138 }
1139 
1140 void cycling_power_service_server_set_first_crank_measurement_angle(uint16_t first_crank_measurement_angle_deg){
1141     cycling_power_t * instance = &cycling_power;
1142     instance->vector_first_crank_measurement_angle_deg = first_crank_measurement_angle_deg;
1143 }
1144 
1145 void cycling_power_service_server_set_instantaneous_measurement_direction(cycling_power_instantaneous_measurement_direction_t direction){
1146     cycling_power_t * instance = &cycling_power;
1147     instance->vector_instantaneous_measurement_direction = direction;
1148 }
1149 
1150 void cycling_power_service_server_set_force_magnitude(int16_t min_force_magnitude_newton, int16_t max_force_magnitude_newton){
1151     cycling_power_t * instance = &cycling_power;
1152     instance->minimum_force_magnitude_newton = min_force_magnitude_newton;
1153     instance->maximum_force_magnitude_newton = max_force_magnitude_newton;
1154 }
1155 
1156 void cycling_power_service_server_set_torque_magnitude(int16_t min_torque_magnitude_newton, int16_t max_torque_magnitude_newton){
1157     cycling_power_t * instance = &cycling_power;
1158     instance->minimum_torque_magnitude_newton_m = min_torque_magnitude_newton;
1159     instance->maximum_torque_magnitude_newton_m = max_torque_magnitude_newton;
1160 }
1161 
1162 void cycling_power_service_server_set_angle(uint16_t min_angle_deg, uint16_t max_angle_deg){
1163     cycling_power_t * instance = &cycling_power;
1164     instance->minimum_angle_deg = min_angle_deg;
1165     instance->maximum_angle_deg = max_angle_deg;
1166 }
1167 
1168 void cycling_power_service_server_set_top_dead_spot_angle(uint16_t top_dead_spot_angle_deg){
1169     cycling_power_t * instance = &cycling_power;
1170     instance->top_dead_spot_angle_deg = top_dead_spot_angle_deg;
1171 }
1172 
1173 void cycling_power_service_server_set_bottom_dead_spot_angle(uint16_t bottom_dead_spot_angle_deg){
1174     cycling_power_t * instance = &cycling_power;
1175     instance->bottom_dead_spot_angle_deg = bottom_dead_spot_angle_deg;
1176 }
1177 
1178 static int gatt_date_is_valid(gatt_date_time_t date){
1179     if ((date.year != 0u) && ((date.year < 1582u) || (date.year > 9999u))) return 0u;
1180     if ((date.month != 0u) && (date.month > 12u)) return 0u;
1181     if ((date.day != 0u) && (date.day > 31u)) return 0u;
1182 
1183     if (date.hours > 23u) return 0u;
1184     if (date.minutes > 59u) return 0u;
1185     if (date.seconds > 59u) return 0u;
1186     return 1;
1187 }
1188 
1189 int cycling_power_service_server_set_factory_calibration_date(gatt_date_time_t date){
1190     if (!gatt_date_is_valid(date)) return 0;
1191 
1192     cycling_power_t * instance = &cycling_power;
1193     instance->factory_calibration_date = date;
1194     return 1;
1195 }
1196 
1197 void cycling_power_service_server_set_sampling_rate(uint8_t sampling_rate_hz){
1198     cycling_power_t * instance = &cycling_power;
1199     instance->sampling_rate_hz = sampling_rate_hz;
1200 }
1201 
1202 
1203 void cycling_power_service_server_update_values(void){
1204     cycling_power_t * instance = &cycling_power;
1205 
1206     if (instance->measurement_server_configuration_descriptor_broadcast){
1207         instance->measurement_broadcast_callback.callback = &cycling_power_service_broadcast_can_send_now;
1208         instance->measurement_broadcast_callback.context  = (void*) instance;
1209         att_server_register_can_send_now_callback(&instance->measurement_broadcast_callback, instance->con_handle);
1210     }
1211 
1212     if (instance->measurement_client_configuration_descriptor_notify){
1213         instance->measurement_notify_callback.callback = &cycling_power_service_measurement_can_send_now;
1214         instance->measurement_notify_callback.context  = (void*) instance;
1215         att_server_register_can_send_now_callback(&instance->measurement_notify_callback, instance->con_handle);
1216     }
1217 
1218     if (instance->vector_client_configuration_descriptor_notify){
1219         instance->vector_notify_callback.callback = &cycling_power_service_vector_can_send_now;
1220         instance->vector_notify_callback.context  = (void*) instance;
1221         att_server_register_can_send_now_callback(&instance->vector_notify_callback, instance->con_handle);
1222     }
1223 }
1224 
1225 void cycling_power_service_server_packet_handler(btstack_packet_handler_t callback){
1226     if (callback == NULL){
1227         log_error("cycling_power_service_server_packet_handler called with NULL callback");
1228         return;
1229     }
1230     cycling_power_t * instance = &cycling_power;
1231     instance->calibration_callback = callback;
1232 }
1233 
1234 void cycling_power_server_calibration_done(cycling_power_sensor_measurement_context_t measurement_type, uint16_t calibrated_value){
1235     cycling_power_t * instance = &cycling_power;
1236     if (instance->response_value != CP_RESPONSE_VALUE_W4_VALUE_AVAILABLE){
1237         // printf("cycling_power_server_calibration_done : CP_RESPONSE_VALUE_W4_VALUE_AVAILABLE con_handle 0x%02x\n", instance->con_handle);
1238         return;
1239     }
1240     instance->response_value = CP_RESPONSE_VALUE_SUCCESS;
1241 
1242     switch (measurement_type){
1243         case CP_SENSOR_MEASUREMENT_CONTEXT_FORCE:
1244             instance->current_force_magnitude_newton = calibrated_value;
1245             break;
1246         case CP_SENSOR_MEASUREMENT_CONTEXT_TORQUE:
1247             instance->current_torque_magnitude_newton_m = calibrated_value;
1248             break;
1249         default:
1250             instance->response_value = CP_RESPONSE_VALUE_INVALID_PARAMETER;
1251             break;
1252     }
1253 
1254     if (instance->response_value == CP_RESPONSE_VALUE_SUCCESS){
1255         switch (calibrated_value){
1256             case CP_CALIBRATION_STATUS_INCORRECT_CALIBRATION_POSITION:
1257             case CP_CALIBRATION_STATUS_MANUFACTURER_SPECIFIC_ERROR_FOLLOWS:
1258                 instance->response_value = CP_RESPONSE_VALUE_OPERATION_FAILED;
1259                 instance->response_value = CP_RESPONSE_VALUE_OPERATION_FAILED;
1260                 break;
1261             default:
1262                 break;
1263         }
1264     }
1265 
1266     if (instance->control_point_client_configuration_descriptor_indicate){
1267         instance->control_point_indicate_callback.callback = &cycling_power_service_response_can_send_now;
1268         instance->control_point_indicate_callback.context  = (void*) instance;
1269         att_server_register_can_send_now_callback(&instance->control_point_indicate_callback, instance->con_handle);
1270     }
1271 }
1272 
1273 void cycling_power_server_enhanced_calibration_done(cycling_power_sensor_measurement_context_t measurement_type,
1274                 uint16_t calibrated_value, uint16_t manufacturer_company_id,
1275                 uint8_t num_manufacturer_specific_data, uint8_t * manufacturer_specific_data){
1276     cycling_power_t * instance = &cycling_power;
1277     if (instance->response_value != CP_RESPONSE_VALUE_W4_VALUE_AVAILABLE) return;
1278     instance->response_value = CP_RESPONSE_VALUE_SUCCESS;
1279 
1280     switch (measurement_type){
1281         case CP_SENSOR_MEASUREMENT_CONTEXT_FORCE:
1282             instance->current_force_magnitude_newton = calibrated_value;
1283             break;
1284         case CP_SENSOR_MEASUREMENT_CONTEXT_TORQUE:
1285             instance->current_torque_magnitude_newton_m = calibrated_value;
1286             break;
1287         default:
1288             instance->response_value = CP_RESPONSE_VALUE_INVALID_PARAMETER;
1289             break;
1290     }
1291 
1292     if (instance->response_value == CP_RESPONSE_VALUE_SUCCESS){
1293         switch (calibrated_value){
1294             case CP_CALIBRATION_STATUS_INCORRECT_CALIBRATION_POSITION:
1295             case CP_CALIBRATION_STATUS_MANUFACTURER_SPECIFIC_ERROR_FOLLOWS:
1296                 instance->response_value = CP_RESPONSE_VALUE_OPERATION_FAILED;
1297                 instance->response_value = CP_RESPONSE_VALUE_OPERATION_FAILED;
1298                 break;
1299             default:
1300                 break;
1301         }
1302         instance->manufacturer_company_id = manufacturer_company_id;
1303         instance->num_manufacturer_specific_data = num_manufacturer_specific_data;
1304         instance->manufacturer_specific_data = manufacturer_specific_data;
1305     }
1306 
1307     if (instance->control_point_client_configuration_descriptor_indicate){
1308         instance->control_point_indicate_callback.callback = &cycling_power_service_response_can_send_now;
1309         instance->control_point_indicate_callback.context  = (void*) instance;
1310         att_server_register_can_send_now_callback(&instance->control_point_indicate_callback, instance->con_handle);
1311     }
1312 }
1313