nimble/host: Fix legacy advertising API with EXT_ADV enabled

Configured advertisign instance is required in order to set advertising
data when extended advertising HCI is used. Since when legacy PDU are
in use we can set both AD and SCAN_RSP we can easily pre-configure
selected instance just for this purpose and re-configure it before
starting advertising without affecting set AD/SCAN_RSP.

nimble/host/src/ble_gap.c

@@ -202,6 +202,10 @@ struct ble_gap_slave_state {
 
 static bssnz_t struct ble_gap_slave_state ble_gap_slave[BLE_ADV_INSTANCES];
 
+#if MYNEWT_VAL(BLE_EXT_ADV)
+static bool ext_adv_legacy_configured = false;
+#endif
+
 struct ble_gap_update_entry {
     SLIST_ENTRY(ble_gap_update_entry) next;
     struct ble_gap_upd_params params;
@@ -1471,6 +1475,8 @@ ble_gap_reset_state(int reason)
             ble_gap_adv_finished(i, reason, 0, 0);
         }
     }
+
+    ext_adv_legacy_configured = false;
 #else
     if (ble_gap_adv_active_instance(0)) {
         /* Indicate to application that advertising has stopped. */
@@ -2540,7 +2546,13 @@ ble_gap_adv_stop(void)
         return rc;
     }
 
-    return ble_gap_ext_adv_remove(MYNEWT_VAL(BLE_HS_EXT_ADV_LEGACY_INSTANCE));
+    rc = ble_gap_ext_adv_remove(MYNEWT_VAL(BLE_HS_EXT_ADV_LEGACY_INSTANCE));
+    if (rc) {
+        return rc;
+    }
+
+    ext_adv_legacy_configured = false;
+    return 0;
 #else
     int rc;
 
@@ -2792,13 +2804,15 @@ ble_gap_adv_start(uint8_t own_addr_type, const ble_addr_t *direct_addr,
     ext_params.filter_policy = adv_params->filter_policy;
     ext_params.high_duty_directed = adv_params->high_duty_cycle;
 
-    /* configure instance 0 */
+    /* configure legacy instance */
     rc = ble_gap_ext_adv_configure(MYNEWT_VAL(BLE_HS_EXT_ADV_LEGACY_INSTANCE),
                                    &ext_params, NULL, cb, cb_arg);
     if (rc) {
         return rc;
     }
 
+    ext_adv_legacy_configured = true;
+
     if (duration_ms == BLE_HS_FOREVER) {
         duration = 0;
     } else {
@@ -2888,6 +2902,38 @@ ble_gap_adv_start(uint8_t own_addr_type, const ble_addr_t *direct_addr,
 #endif
 }
 
+#if MYNEWT_VAL(BLE_EXT_ADV)
+static int
+ble_gap_ext_adv_legacy_preconfigure(void)
+{
+    struct ble_gap_ext_adv_params ext_params;
+    int rc;
+
+    if (ext_adv_legacy_configured) {
+        return 0;
+    }
+
+    memset(&ext_params, 0, sizeof(ext_params));
+    ext_params.own_addr_type = BLE_ADDR_RANDOM;
+    ext_params.primary_phy = BLE_HCI_LE_PHY_1M;
+    ext_params.secondary_phy = BLE_HCI_LE_PHY_1M;
+    ext_params.tx_power = 127;
+    ext_params.sid = 0;
+    ext_params.legacy_pdu = 1;
+    ext_params.scannable = 1;
+    ext_params.connectable = 1;
+
+    rc = ble_gap_ext_adv_configure(MYNEWT_VAL(BLE_HS_EXT_ADV_LEGACY_INSTANCE),
+                                   &ext_params, NULL, NULL, NULL);
+    if (rc) {
+        return rc;
+    }
+
+    ext_adv_legacy_configured = true;
+    return 0;
+}
+#endif
+
 int
 ble_gap_adv_set_data(const uint8_t *data, int data_len)
 {
@@ -2901,6 +2947,11 @@ ble_gap_adv_set_data(const uint8_t *data, int data_len)
         return BLE_HS_EINVAL;
     }
 
+    rc = ble_gap_ext_adv_legacy_preconfigure();
+    if (rc) {
+        return rc;
+    }
+
     mbuf = os_msys_get_pkthdr(data_len, 0);
     if (!mbuf) {
         return BLE_HS_ENOMEM;
@@ -2954,6 +3005,11 @@ ble_gap_adv_rsp_set_data(const uint8_t *data, int data_len)
         return BLE_HS_EINVAL;
     }
 
+    rc = ble_gap_ext_adv_legacy_preconfigure();
+    if (rc) {
+        return rc;
+    }
+
     mbuf = os_msys_get_pkthdr(data_len, 0);
     if (!mbuf) {
         return BLE_HS_ENOMEM;