extmod/modbluetooth: Allow using mp_hal_get_mac as a static address.

Generally a controller should either have its own public address hardcoded,
or loaded by the driver (e.g. cywbt43).

However, for a controller that has no public address where you still want a
long-term stable address, this allows you to use a static address generated
by the port.  Typically on STM32 this will be an LAA, but a board might
override this.

1 files changed, 15 insertions, 3 deletions

diff --git a/extmod/nimble/modbluetooth_nimble.c b/extmod/nimble/modbluetooth_nimble.c
index 1c782943a..4222f58fa 100644
--- a/extmod/nimble/modbluetooth_nimble.c
+++ b/extmod/nimble/modbluetooth_nimble.c
@@ -157,10 +157,22 @@ STATIC bool has_public_address(void) {
 STATIC void set_random_address(bool nrpa) {
     int rc;
     (void)rc;
-    DEBUG_printf("sync_cb: Generating random static address\n");
     ble_addr_t addr;
-    rc = ble_hs_id_gen_rnd(nrpa ? 1 : 0, &addr);
-    assert(rc == 0);
+    #if MICROPY_BLUETOOTH_USE_MP_HAL_GET_MAC_STATIC_ADDRESS
+    if (!nrpa) {
+        DEBUG_printf("set_random_address: Generating static address using mp_hal_get_mac\n");
+        uint8_t hal_mac_addr[6];
+        mp_hal_get_mac(MP_HAL_MAC_BDADDR, hal_mac_addr);
+        addr = create_nimble_addr(BLE_ADDR_RANDOM, hal_mac_addr);
+        // Mark it as STATIC (not RPA or NRPA).
+        addr.val[5] |= 0xc0;
+    } else
+    #endif
+    {
+        DEBUG_printf("set_random_address: Generating random static address\n");
+        rc = ble_hs_id_gen_rnd(nrpa ? 1 : 0, &addr);
+        assert(rc == 0);
+    }
     rc = ble_hs_id_set_rnd(addr.val);
     assert(rc == 0);
     rc = ble_hs_util_ensure_addr(1);