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Refactor scan_gatt_event_handler to make characteristic discovery easier
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@shermp
shermp committed Sep 16, 2024
1 parent 8dcb327 commit 91ebda2
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Showing 2 changed files with 70 additions and 108 deletions.
171 changes: 66 additions & 105 deletions src/asha_bt.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -153,6 +153,8 @@ void ScanResult::reset()
service_found = false;
ha = HA();
report = AdvertisingReport();
services.clear();
services_it = services.end();
}

static void handle_bt_audio_pending_worker(async_context_t *context, async_when_pending_worker_t *worker)
Expand Down Expand Up @@ -658,6 +660,14 @@ static void l2cap_cbm_event_handler (uint8_t packet_type, uint16_t channel, uint
}
}

#define GATT_QUERY_ASSERT(cmd, msg) { \
auto res = (cmd); \
if (res != ERROR_CODE_SUCCESS) { \
LOG_ERROR(msg ": 0x%02x", static_cast<unsigned int>(res)); \
scan_state = ScanState::Disconnecting; \
gap_disconnect(curr_scan.ha.conn_handle); \
}}

/* Handler for reading GATT service and characteristic values
and subscribing to the AudioStatusPoint characteristic notification
during the connection process.
Expand All @@ -675,42 +685,41 @@ static void scan_gatt_event_handler (uint8_t packet_type, uint16_t channel, uint
if (service.uuid16 == AshaUUID::service16 || uuid_eq(service.uuid128, AshaUUID::service)) {
memcpy(&curr_scan.ha.asha_service.service, &service, sizeof(service));
curr_scan.service_found = true;
curr_scan.services.push_back(&curr_scan.ha.asha_service.service);
LOG_INFO("ASHA service found");
} else if (service.uuid16 == GapUUID::service16) {
LOG_INFO("GAP service found");
memcpy(&curr_scan.ha.gap_service.service, &service, sizeof(service));
curr_scan.services.push_back(&curr_scan.ha.gap_service.service);
} else if (service.uuid16 == GattUUID::service16) {
LOG_INFO("GATT service found");
memcpy(&curr_scan.ha.gatt_service.service, &service, sizeof(service));
curr_scan.services.push_back(&curr_scan.ha.gatt_service.service);
}

break;
case GATT_EVENT_QUERY_COMPLETE:
{
// Older hearing aids may support MFI but not ASHA
if (!curr_scan.service_found) {
if (!curr_scan.service_found || curr_scan.services.empty()) {
LOG_INFO("ASHA service not found. Continuing scanning");
scan_state = ScanState::Disconnecting;
gap_disconnect(curr_scan.ha.conn_handle);
break;
}
scan_state = ScanState::ServiceChangedCharDiscovery;
curr_scan.services_it = curr_scan.services.begin();
scan_state = ScanState::CharDiscovery;
// Service found. Discover characteristics
auto res = gatt_client_discover_characteristics_for_service(
&scan_gatt_event_handler,
curr_scan.ha.conn_handle,
&curr_scan.ha.gatt_service.service
);
if (res != ERROR_CODE_SUCCESS) {
LOG_ERROR("Could not register GATT characteristics query: %d", static_cast<int>(res));
scan_state = ScanState::Disconnecting;
gap_disconnect(curr_scan.ha.conn_handle);
}
LOG_INFO("Discovering characteristics for found services");
GATT_QUERY_ASSERT(gatt_client_discover_characteristics_for_service(
&scan_gatt_event_handler, curr_scan.ha.conn_handle, *curr_scan.services_it),
"Could not register GATT characteristics query");
break;
}
}
break;
}
case ScanState::ServiceChangedCharDiscovery:
case ScanState::CharDiscovery:
{
gatt_client_characteristic_t characteristic;
switch (hci_event_packet_get_type(packet)) {
Expand All @@ -719,24 +728,48 @@ static void scan_gatt_event_handler (uint8_t packet_type, uint16_t channel, uint
if (characteristic.uuid16 == GattUUID::serviceChanged) {
LOG_INFO("Got Service Changed Characteristic");
curr_scan.ha.gatt_service.service_changed = characteristic;
} else if (characteristic.uuid16 == GapUUID::deviceName16) {
LOG_INFO("Got Device Name Characteristic");
curr_scan.ha.gap_service.device_name = characteristic;
} else if (uuid_eq(characteristic.uuid128, AshaUUID::readOnlyProps)) {
LOG_INFO("Got ROP Characteristic");
curr_scan.ha.asha_service.rop = characteristic;
} else if (uuid_eq(characteristic.uuid128, AshaUUID::audioControlPoint)) {
LOG_INFO("Got ACP Characteristic");
curr_scan.ha.asha_service.acp = characteristic;
} else if (uuid_eq(characteristic.uuid128, AshaUUID::audioStatus)) {
LOG_INFO("Got AUS Characteristic");
curr_scan.ha.asha_service.asp = characteristic;
} else if (uuid_eq(characteristic.uuid128, AshaUUID::volume)) {
LOG_INFO("Got VOL Characteristic");
curr_scan.ha.asha_service.vol = characteristic;
} else if (uuid_eq(characteristic.uuid128, AshaUUID::psm)) {
LOG_INFO("Got PSM Characteristic");
curr_scan.ha.asha_service.psm = characteristic;
}
// LOG_INFO("Characteristic handles: Start: 0x%04hx Value: 0x%04hx End: 0x%04hx",
// characteristic.start_handle, characteristic.value_handle, characteristic.end_handle);
break;
case GATT_EVENT_QUERY_COMPLETE:
LOG_INFO("GATT service characteristic discovery complete");
// Start ASHA characteristic discovery
LOG_INFO("Characteristic discovery complete");
curr_scan.services_it++;
if (curr_scan.services_it != curr_scan.services.end()) {
LOG_INFO("Continue discovering more characteristics");

GATT_QUERY_ASSERT(gatt_client_discover_characteristics_for_service(
&scan_gatt_event_handler, curr_scan.ha.conn_handle, *curr_scan.services_it
), "Could not register GATT characteristics query");
return;
} else {
LOG_INFO("Characteristic discovery complete");
}
scan_state = ScanState::ServiceChangedNotification;
// Service found. Discover characteristics
auto res = gatt_client_write_client_characteristic_configuration(
GATT_QUERY_ASSERT(gatt_client_write_client_characteristic_configuration(
scan_gatt_event_handler,
curr_scan.ha.conn_handle,
&curr_scan.ha.gatt_service.service_changed,
GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_INDICATION
);
if (res != ERROR_CODE_SUCCESS) {
LOG_ERROR("Could not register GATT service changed indication config: %d", static_cast<int>(res));
scan_state = ScanState::Disconnecting;
gap_disconnect(curr_scan.ha.conn_handle);
}
), "Could not register GATT service changed indication config");
break;
}
break;
Expand All @@ -748,96 +781,23 @@ static void scan_gatt_event_handler (uint8_t packet_type, uint16_t channel, uint
{
auto att_res = gatt_event_query_complete_get_att_status(packet);
if (att_res != ATT_ERROR_SUCCESS) {
LOG_ERROR("Subscribing to GATT Service changed indication failed: %d", static_cast<int>(att_res));
LOG_ERROR("Subscribing to GATT Service changed indication failed: 0x%02x", static_cast<unsigned int>(att_res));
scan_state = ScanState::Disconnecting;
gap_disconnect(curr_scan.ha.conn_handle);
break;
return;
}

LOG_INFO("Subscribed to GATT Service changed indication");
scan_state = ScanState::DeviceNameCharDiscovery;
// Service found. Discover characteristics
auto res = gatt_client_discover_characteristics_for_service(
&scan_gatt_event_handler,
curr_scan.ha.conn_handle,
&curr_scan.ha.gap_service.service
);
if (res != ERROR_CODE_SUCCESS) {
LOG_ERROR("Could not register device name characteristics query: %d", static_cast<int>(res));
scan_state = ScanState::Disconnecting;
gap_disconnect(curr_scan.ha.conn_handle);
}
break;
}
}
break;
}
case ScanState::DeviceNameCharDiscovery:
{
gatt_client_characteristic_t characteristic;
switch (hci_event_packet_get_type(packet)) {
case GATT_EVENT_CHARACTERISTIC_QUERY_RESULT:
gatt_event_characteristic_query_result_get_characteristic(packet, &characteristic);
if (characteristic.uuid16 == GapUUID::deviceName16) {
LOG_INFO("Got Device Name Characteristic");
curr_scan.ha.gap_service.device_name = characteristic;
}
break;
case GATT_EVENT_QUERY_COMPLETE:
LOG_INFO("Device name characteristic discovery complete");
// Start ASHA characteristic discovery
scan_state = ScanState::CharDiscovery;
// Service found. Discover characteristics
auto res = gatt_client_discover_characteristics_for_service(
&scan_gatt_event_handler,
curr_scan.ha.conn_handle,
&curr_scan.ha.asha_service.service
);
if (res != ERROR_CODE_SUCCESS) {
LOG_ERROR("Could not register asha characteristics query: %d", static_cast<int>(res));
scan_state = ScanState::Disconnecting;
gap_disconnect(curr_scan.ha.conn_handle);
}
break;
}
break;
}
case ScanState::CharDiscovery:
{
gatt_client_characteristic_t characteristic;
switch (hci_event_packet_get_type(packet)) {
case GATT_EVENT_CHARACTERISTIC_QUERY_RESULT:
gatt_event_characteristic_query_result_get_characteristic(packet, &characteristic);
if (uuid_eq(characteristic.uuid128, AshaUUID::readOnlyProps)) {
LOG_INFO("Got ROP Characteristic");
curr_scan.ha.asha_service.rop = characteristic;
} else if (uuid_eq(characteristic.uuid128, AshaUUID::audioControlPoint)) {
LOG_INFO("Got ACP Characteristic");
curr_scan.ha.asha_service.acp = characteristic;
} else if (uuid_eq(characteristic.uuid128, AshaUUID::audioStatus)) {
LOG_INFO("Got AUS Characteristic");
curr_scan.ha.asha_service.asp = characteristic;
} else if (uuid_eq(characteristic.uuid128, AshaUUID::volume)) {
LOG_INFO("Got VOL Characteristic");
curr_scan.ha.asha_service.vol = characteristic;
} else if (uuid_eq(characteristic.uuid128, AshaUUID::psm)) {
LOG_INFO("Got PSM Characteristic");
curr_scan.ha.asha_service.psm = characteristic;
}
// LOG_INFO("Characteristic handles: Start: 0x%04hx Value: 0x%04hx End: 0x%04hx",
// characteristic.start_handle, characteristic.value_handle, characteristic.end_handle);
break;
case GATT_EVENT_QUERY_COMPLETE:
LOG_INFO("ASHA characteristic discovery complete");
// Start reading the Device name characteristic
scan_state = ScanState::ReadDeviceName;
gatt_client_read_value_of_characteristic(
GATT_QUERY_ASSERT(gatt_client_read_value_of_characteristic(
&scan_gatt_event_handler,
curr_scan.ha.conn_handle,
&curr_scan.ha.gap_service.device_name
);
), "Could not register read of device name");
break;
}
}
break;
}
case ScanState::ReadDeviceName:
Expand All @@ -856,11 +816,11 @@ static void scan_gatt_event_handler (uint8_t packet_type, uint16_t channel, uint
LOG_INFO("Completed value read of Device Name");
// Start reading the Read Only Properties characteristic
scan_state = ScanState::ReadROP;
gatt_client_read_value_of_characteristic(
GATT_QUERY_ASSERT(gatt_client_read_value_of_characteristic(
&scan_gatt_event_handler,
curr_scan.ha.conn_handle,
&curr_scan.ha.asha_service.rop
);
), "Could not register read of ROP");
break;
}
break;
Expand All @@ -877,11 +837,11 @@ static void scan_gatt_event_handler (uint8_t packet_type, uint16_t channel, uint
LOG_INFO("Completed value read of ReadOnlyProperties");
/* Next get the PSM value */
scan_state = ScanState::ReadPSM;
gatt_client_read_value_of_characteristic(
GATT_QUERY_ASSERT(gatt_client_read_value_of_characteristic(
&scan_gatt_event_handler,
curr_scan.ha.conn_handle,
&curr_scan.ha.asha_service.psm
);
), "Could not register read of PSM");
break;
}
break;
Expand Down Expand Up @@ -960,6 +920,7 @@ static void finalise_curr_discovery()
curr_scan.ha.l2cap_packet_handler = &l2cap_cbm_event_handler;
curr_scan.ha.gatt_packet_handler = &connected_gatt_event_handler;
auto& ha = ha_mgr.add(curr_scan.ha);
curr_scan.reset();
if (!ha) {
LOG_ERROR("Error adding this device.");
scan_state = ScanState::Scan;
Expand Down
7 changes: 4 additions & 3 deletions src/asha_bt.hpp
View file
Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
#pragma once

#include <cstdint>
#include "etl/vector.h"
#include "btstack.h"

#include "hearing_aid.hpp"
Expand All @@ -16,10 +17,8 @@ enum class ScanState {
Disconnecting,
DataLen,
ServiceDiscovery,
ServiceChangedCharDiscovery,
ServiceChangedNotification,
DeviceNameCharDiscovery,
CharDiscovery,
ServiceChangedNotification,
ReadDeviceName,
ReadROP,
ReadPSM,
Expand Down Expand Up @@ -55,6 +54,8 @@ struct ScanResult {
bool service_found = false;
HA ha = HA();
AdvertisingReport report = AdvertisingReport();
etl::vector<gatt_client_service_t*, 8> services = {};
gatt_client_service_t** services_it = services.end();
void reset();
};

Expand Down

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