sys/bluetooth: fix UART service not working after reconnect

If Bluetooth disconnected while sending data via the Nordic UART
service, then that service would no longer work after reconnecting.

This happened because of a combination of:

1. The current message never had the is_queued flag cleared because it
   was no longer in the queue and the send_done callback as never
   called.
2. Some of the Bluetooth drivers did not reset internal state properly
   after "power off" of the chip (contiki process stopped abruptly).

This is fixed by keeping the active message in the queue until either
send_done() or reset_all() is called. This guarantees that the message
will always be properly cleaned up.

The affected drivers are also fixed.

Issue: pybricks/support#325

Author: dlech

lib/pbio/drv/bluetooth/bluetooth_btstack.c

@@ -63,7 +63,7 @@ static void pybricks_can_send(void *context) {
     pbdrv_bluetooth_send_context_t *send = context;
 
     pybricks_service_server_send(pybricks_con_handle, send->data, send->size);
-    send->done(send);
+    send->done();
 }
 
 static void pybricks_data_received(hci_con_handle_t tx_con_handle, const uint8_t *data, uint16_t size) {
@@ -80,7 +80,7 @@ static void nordic_can_send(void *context) {
     pbdrv_bluetooth_send_context_t *send = context;
 
     nordic_spp_service_server_send(uart_con_handle, send->data, send->size);
-    send->done(send);
+    send->done();
 }
 
 static void nordic_spp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) {

lib/pbio/drv/bluetooth/bluetooth_stm32_bluenrg.c

@@ -308,7 +308,7 @@ static PT_THREAD(send_value_notification(struct pt *pt, void *context))
     }
 
 done:
-    send->done(send);
+    send->done();
 
     PT_END(pt);
 }
@@ -761,8 +761,11 @@ PROCESS_THREAD(pbdrv_bluetooth_spi_process, ev, data) {
     static struct pt child_pt;
 
     PROCESS_EXITHANDLER({
+        spi_disable_cs();
         bluetooth_reset(true);
-        bluetooth_ready = false;
+        bluetooth_ready = pybricks_notify_en = uart_tx_notify_en = false;
+        conn_handle = 0;
+        PROCESS_EXIT();
     });
 
     PROCESS_BEGIN();

lib/pbio/drv/bluetooth/bluetooth_stm32_cc2640.c

@@ -363,7 +363,7 @@ static PT_THREAD(send_value_notification(struct pt *pt, void *context))
     }
 
 done:
-    send->done(send);
+    send->done();
 
     PT_END(pt);
 }
@@ -1149,7 +1149,9 @@ PROCESS_THREAD(pbdrv_bluetooth_spi_process, ev, data) {
     PROCESS_EXITHANDLER({
         spi_set_mrdy(false);
         bluetooth_reset(RESET_STATE_OUT_LOW);
-        bluetooth_ready = false;
+        bluetooth_ready = pybricks_notify_en = uart_tx_notify_en = false;
+        conn_handle = NO_CONNECTION;
+        PROCESS_EXIT();
     });
 
     PROCESS_BEGIN();

lib/pbio/include/pbdrv/bluetooth.h

@@ -37,9 +37,8 @@ typedef void (*pbdrv_bluetooth_on_event_t)(void);
 
 /**
  * Callback that is called when sending a notification is done.
- * @param context  [in]     The context that was given to pbdrv_bluetooth_send().
  */
-typedef void (*pbdrv_bluetooth_send_done_t)(pbdrv_bluetooth_send_context_t *context);
+typedef void (*pbdrv_bluetooth_send_done_t)(void);
 
 /**
  * Callback that is called when BLE characteristic is written to.

lib/pbio/sys/bluetooth.c

@@ -160,8 +160,8 @@ static void handle_receive(pbdrv_bluetooth_connection_t connection, const uint8_
     }
 }
 
-static void send_done(pbdrv_bluetooth_send_context_t *context) {
-    send_msg_t *msg = PBIO_CONTAINER_OF(context, send_msg_t, context);
+static void send_done(void) {
+    send_msg_t *msg = list_pop(send_queue);
 
     if (msg->context.connection == PBDRV_BLUETOOTH_CONNECTION_UART && lwrb_get_full(&uart_tx_ring)) {
         // If there is more buffered data to send, put the message back in the queue
@@ -270,8 +270,8 @@ PROCESS_THREAD(pbsys_bluetooth_process, ev, data) {
             }
 
             if (!send_busy) {
-                send_msg_t *msg = list_pop(send_queue);
-                // msg->is_queued is set to false in send_done callback rather than here
+                // msg is removed from queue in send_done callback rather than here
+                send_msg_t *msg = list_head(send_queue);
                 if (msg) {
                     msg->context.done = send_done;
                     if (msg->context.connection == PBDRV_BLUETOOTH_CONNECTION_UART) {