extmod/nimble: Add timeout to deinit.

If the BLE radio stops responding before deinit is called the
function can get stuck waiting for an event that is never received, particularly if the radio is external or on a separate core.

Signed-off-by: Andrew Leech <andrew.leech@planetinnovation.com.au>

Author: pi-anl

extmod/nimble/modbluetooth_nimble.c

@@ -60,6 +60,7 @@
 static uint8_t nimble_address_mode = BLE_OWN_ADDR_RANDOM;
 
 #define NIMBLE_STARTUP_TIMEOUT 2000
+#define NIMBLE_SHUTDOWN_TIMEOUT 500
 
 // Any BLE_HS_xxx code not in this table will default to MP_EIO.
 static int8_t ble_hs_err_to_errno_table[] = {
@@ -562,8 +563,19 @@ void mp_bluetooth_nimble_port_shutdown(void) {
 
     ble_hs_stop(&ble_hs_shutdown_stop_listener, ble_hs_shutdown_stop_cb, NULL);
 
+    mp_uint_t start = mp_hal_ticks_ms();
     while (mp_bluetooth_nimble_ble_state != MP_BLUETOOTH_NIMBLE_BLE_STATE_OFF) {
-        mp_event_wait_indefinite();
+        if ((mp_hal_ticks_ms() - start) > NIMBLE_SHUTDOWN_TIMEOUT) {
+            break;
+        }
+        mp_event_wait_ms(1);
+    }
+
+    // Failure to correctly shutdown can be detected in application by querying
+    // BLE().active(), else as part of shutdown sequece will usually be resolved
+    // after reset anyway.
+    if (mp_bluetooth_nimble_ble_state != MP_BLUETOOTH_NIMBLE_BLE_STATE_OFF) {
+        DEBUG_printf("mp_bluetooth_nimble_port_shutdown failed: timeout\n");
     }
 }
 
@@ -629,13 +641,12 @@ int mp_bluetooth_init(void) {
 
     // Run the scheduler while we wait for stack startup.
     // On non-ringbuffer builds (NimBLE on STM32/Unix) this will also poll the UART and run the event queue.
-    mp_uint_t timeout_start_ticks_ms = mp_hal_ticks_ms();
+    volatile mp_uint_t start = mp_hal_ticks_ms();
     while (mp_bluetooth_nimble_ble_state != MP_BLUETOOTH_NIMBLE_BLE_STATE_ACTIVE) {
-        uint32_t elapsed = mp_hal_ticks_ms() - timeout_start_ticks_ms;
-        if (elapsed > NIMBLE_STARTUP_TIMEOUT) {
+        if ((mp_hal_ticks_ms() - start) > NIMBLE_STARTUP_TIMEOUT) {
             break;
         }
-        mp_event_wait_ms(NIMBLE_STARTUP_TIMEOUT - elapsed);
+        mp_event_wait_ms(1);
     }
 
     if (mp_bluetooth_nimble_ble_state != MP_BLUETOOTH_NIMBLE_BLE_STATE_ACTIVE) {