sys/bluetooth: keep Bluetooth chip on when not connected

This changes the logic in sys/bluetooth to keep the Bluetooth chip on
while a user program is running, even when not connected to a central.
This allows the program to initiate a connection to a Bluetooth device
like the Powered Up remote control.

This also required implementing a new drv/bluetooth function to stop
advertising when a user program starts.

Author: dlech

CHANGELOG.md

@@ -12,6 +12,7 @@
 - Added configuration option to run a simplified version of motor PID control.
   It is activated on the Move Hub to reduce build size. Motor performance on
   the other hubs is unaffected.
+- Experimental support for the Powered Up remote control ([support#186]).
 
 ### Changed
 - Updated MicroPython to v1.16.
@@ -43,6 +44,7 @@ Prerelease changes are documented at [support#48].
 [issue#49]: https://github.com/pybricks/pybricks-micropython/issues/49
 [support#48]: https://github.com/pybricks/support/issues/48
 [support#52]: https://github.com/pybricks/support/issues/52
+[support#186]: https://github.com/pybricks/support/issues/186
 [support#321]: https://github.com/pybricks/support/issues/321
 [support#347]: https://github.com/pybricks/support/issues/347
 [support#352]: https://github.com/pybricks/support/issues/352

lib/BlueNRG-MS/hci/controller/bluenrg_gap_aci.c

@@ -66,17 +66,28 @@ tBleStatus aci_gap_init_end(uint16_t* service_handle, uint16_t* dev_name_char_ha
   return 0;
 }
 
-tBleStatus aci_gap_set_non_discoverable(void)
+tBleStatus aci_gap_set_non_discoverable_begin(void)
 {
   struct hci_request rq;
-  uint8_t status;
 
   memset(&rq, 0, sizeof(rq));
   rq.opcode = cmd_opcode_pack(OGF_VENDOR_CMD, OCF_GAP_SET_NON_DISCOVERABLE);
+
+  hci_send_req(&rq);
+
+  return 0;
+}
+
+tBleStatus aci_gap_set_non_discoverable_end(void)
+{
+  struct hci_response rq;
+  uint8_t status;
+
+  memset(&rq, 0, sizeof(rq));
   rq.rparam = &status;
   rq.rlen = 1;
 
-  hci_send_req(&rq);
+  hci_recv_resp(&rq);
 
   return status;
 }

lib/BlueNRG-MS/includes/bluenrg_gap_aci.h

@@ -76,7 +76,9 @@ tBleStatus aci_gap_init_end(uint16_t* service_handle,
   * @note    This command will disable the LL advertising.
   * @retval  tBleStatus Value indicating success or error code.
   */
-tBleStatus aci_gap_set_non_discoverable(void);
+tBleStatus aci_gap_set_non_discoverable_begin(void);
+
+tBleStatus aci_gap_set_non_discoverable_end(void);
 
 /**
  * @brief  Put the device in limited discoverable mode

lib/pbio/drv/bluetooth/bluetooth_btstack.c

@@ -259,6 +259,10 @@ void pbdrv_bluetooth_start_advertising(void) {
     gap_advertisements_enable(true);
 }
 
+void pbdrv_bluetooth_stop_advertising(void) {
+    gap_advertisements_enable(false);
+}
+
 bool pbdrv_bluetooth_is_connected(pbdrv_bluetooth_connection_t connection) {
     if (connection == PBDRV_BLUETOOTH_CONNECTION_LE && le_con_handle != HCI_CON_HANDLE_INVALID) {
         return true;

lib/pbio/drv/bluetooth/bluetooth_stm32_bluenrg.c

@@ -238,6 +238,25 @@ void pbdrv_bluetooth_start_advertising(void) {
     pbio_task_start(task_queue, &task);
 }
 
+static PT_THREAD(set_non_discoverable(struct pt *pt, pbio_task_t *task)) {
+    PT_BEGIN(pt);
+
+    PT_WAIT_WHILE(pt, write_xfer_size);
+    aci_gap_set_non_discoverable_begin();
+    PT_WAIT_UNTIL(pt, hci_command_complete);
+    aci_gap_set_non_discoverable_end();
+
+    task->status = PBIO_SUCCESS;
+
+    PT_END(pt);
+}
+
+void pbdrv_bluetooth_stop_advertising(void) {
+    static pbio_task_t task;
+    pbio_task_init(&task, set_non_discoverable, NULL);
+    pbio_task_start(task_queue, &task);
+}
+
 bool pbdrv_bluetooth_is_connected(pbdrv_bluetooth_connection_t connection) {
     if (connection == PBDRV_BLUETOOTH_CONNECTION_LE && conn_handle) {
         return true;

lib/pbio/drv/bluetooth/bluetooth_stm32_cc2640.c

@@ -289,6 +289,28 @@ void pbdrv_bluetooth_start_advertising(void) {
     pbio_task_start(task_queue, &task);
 }
 
+static PT_THREAD(set_non_discoverable(struct pt *pt, pbio_task_t *task)) {
+    PT_BEGIN(pt);
+
+    PT_WAIT_WHILE(pt, write_xfer_size);
+    GAP_endDiscoverable();
+    PT_WAIT_UNTIL(pt, hci_command_complete);
+    // ignoring response data
+
+    // REVISIT: technically, this isn't complete until GAP_EndDiscoverableDone
+    // event is received
+
+    task->status = PBIO_SUCCESS;
+
+    PT_END(pt);
+}
+
+void pbdrv_bluetooth_stop_advertising(void) {
+    static pbio_task_t task;
+    pbio_task_init(&task, set_non_discoverable, NULL);
+    pbio_task_start(task_queue, &task);
+}
+
 bool pbdrv_bluetooth_is_connected(pbdrv_bluetooth_connection_t connection) {
     if (connection == PBDRV_BLUETOOTH_CONNECTION_LE && conn_handle != NO_CONNECTION) {
         return true;

lib/pbio/include/pbdrv/bluetooth.h

@@ -89,6 +89,13 @@ bool pbdrv_bluetooth_is_ready(void);
  */
 void pbdrv_bluetooth_start_advertising(void);
 
+/**
+ * Stops the advertising process.
+ *
+ * This only needs to be called when no central connects to the hub.
+ */
+void pbdrv_bluetooth_stop_advertising(void);
+
 /**
  * Tests if a central is connected to the Bluetooth chip.
  * @param [in]  connection  The type of connection of interest.

lib/pbio/sys/bluetooth.c

@@ -249,6 +249,12 @@ PROCESS_THREAD(pbsys_bluetooth_process, ev, data) {
         pbsys_status_set(PBIO_PYBRICKS_STATUS_BLE_ADVERTISING);
         PROCESS_WAIT_UNTIL(pbdrv_bluetooth_is_connected(PBDRV_BLUETOOTH_CONNECTION_LE) ||
             pbsys_status_test(PBIO_PYBRICKS_STATUS_USER_PROGRAM_RUNNING));
+
+        if (!pbdrv_bluetooth_is_connected(PBDRV_BLUETOOTH_CONNECTION_LE)) {
+            // if a connection wasn't made, we need to manually stop advertising
+            pbdrv_bluetooth_stop_advertising();
+        }
+
         pbsys_status_clear(PBIO_PYBRICKS_STATUS_BLE_ADVERTISING);
 
         PT_INIT(&status_monitor_pt);
@@ -288,11 +294,11 @@ PROCESS_THREAD(pbsys_bluetooth_process, ev, data) {
         }
 
         reset_all();
+        PROCESS_WAIT_WHILE(pbsys_status_test(PBIO_PYBRICKS_STATUS_USER_PROGRAM_RUNNING));
 
         // reset Bluetooth chip
         pbdrv_bluetooth_power_on(false);
         PROCESS_WAIT_WHILE(pbdrv_bluetooth_is_ready());
-        PROCESS_WAIT_WHILE(pbsys_status_test(PBIO_PYBRICKS_STATUS_USER_PROGRAM_RUNNING));
     }
 
     PROCESS_END();