extmod/btstack: Reset pending_value_handle before calling read-done cb.

Similar to the previous commit but for MP_BLUETOOTH_IRQ_GATTC_READ_DONE:
the pending_value_handle needs to be reset before calling
mp_bluetooth_gattc_on_read_write_status(), which will call the Python IRQ
handler, which may in turn call back into BTstack to perform an action like
a write.  In that case the pending_value_handle will need to be available
for the write/read/etc to proceed.

Fixes issue #13634.

Signed-off-by: Damien George <damien@micropython.org>

extmod/btstack/modbluetooth_btstack.c

@@ -462,8 +462,9 @@ STATIC void btstack_packet_handler_read(uint8_t packet_type, uint16_t channel, u
         if (!conn) {
             return;
         }
-        mp_bluetooth_gattc_on_read_write_status(MP_BLUETOOTH_IRQ_GATTC_READ_DONE, conn_handle, conn->pending_value_handle, status);
+        uint16_t value_handle = conn->pending_value_handle;
         conn->pending_value_handle = 0xffff;
+        mp_bluetooth_gattc_on_read_write_status(MP_BLUETOOTH_IRQ_GATTC_READ_DONE, conn_handle, value_handle, status);
     } else if (event_type == GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT) {
         DEBUG_printf("  --> gatt characteristic value query result\n");
         uint16_t conn_handle = gatt_event_characteristic_value_query_result_get_handle(packet);

tests/multi_bluetooth/ble_irq_calls.py

@@ -65,8 +65,9 @@ class Central:
         self.done = False
         self._conn_handle = None
         self._service = None
-        self._characteristic = None
+        self._characteristic_handle = None
         self._cccd_handle = None
+        self._reads_remaining = None
         ble.active(1)
         ble.irq(self._ble_event_handler)
         ble.gap_connect(*BDADDR)
@@ -101,7 +102,8 @@ class Central:
             _, end_handle, value_handle, properties, uuid = data
             assert uuid == STATE_UUID
             print("characteristic found:", uuid)
-            self._characteristic = (end_handle, value_handle, properties)
+            assert self._characteristic_handle is None
+            self._characteristic_handle = value_handle
 
         elif event == _IRQ_GATTC_CHARACTERISTIC_DONE:
             start_handle, end_handle = self._service
@@ -128,17 +130,21 @@ class Central:
         elif event == _IRQ_GATTC_WRITE_DONE:
             conn_handle, _, result = data
             print("CCCD write result:", result)
-            _, state_handle, _ = self._characteristic
             print("issue gattc_read")
-            ble.gattc_read(self._conn_handle, state_handle)
+            self._reads_remaining = 2
+            ble.gattc_read(self._conn_handle, self._characteristic_handle)
 
         elif event == _IRQ_GATTC_READ_RESULT:
             _, _, char_data = data
             print("gattc_read result:", bytes(char_data))
 
         elif event == _IRQ_GATTC_READ_DONE:
-            self.done = True
-            ble.gap_disconnect(self._conn_handle)
+            self._reads_remaining -= 1
+            if self._reads_remaining > 0:
+                ble.gattc_read(self._conn_handle, self._characteristic_handle)
+            else:
+                self.done = True
+                ble.gap_disconnect(self._conn_handle)
 
 
 class Peripheral:

tests/multi_bluetooth/ble_irq_calls.py.exp

@@ -3,6 +3,7 @@ peripheral start
 _IRQ_CENTRAL_CONNECT
 _IRQ_MTU_EXCHANGED
 _IRQ_GATTS_READ_REQUEST
+_IRQ_GATTS_READ_REQUEST
 _IRQ_CENTRAL_DISCONNECT
 --- instance1 ---
 central start
@@ -27,5 +28,8 @@ issue gattc_read
 _IRQ_GATTC_READ_RESULT
 gattc_read result: b''
 _IRQ_GATTC_READ_DONE
+_IRQ_GATTC_READ_RESULT
+gattc_read result: b''
+_IRQ_GATTC_READ_DONE
 _IRQ_PERIPHERAL_DISCONNECT
 connection closed