Add GNSS HAL 2.1

Bug: 136136192
Bug: 141758837

Test: atest VtsHalGnssV2_1TargetTest
Change-Id: I8e6d52695c8ab0aeacacb0107a6c0c8271983ed3
diff --git a/gnss/2.1/IGnssCallback.hal b/gnss/2.1/IGnssCallback.hal
new file mode 100644
index 0000000..da70742
--- /dev/null
+++ b/gnss/2.1/IGnssCallback.hal
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.hardware.gnss@2.1;
+
+import @2.0::IGnssCallback;
+
+/**
+ * This interface is required for the HAL to communicate certain information
+ * like status and location info back to the platform, the platform implements
+ * the interfaces and passes a handle to the HAL.
+ */
+interface IGnssCallback extends @2.0::IGnssCallback {
+
+    /** Extends a GnssSvInfo, adding a basebandCN0DbHz. */
+    struct GnssSvInfo {
+        /**
+         * GNSS satellite information for a single satellite and frequency.
+         */
+        @2.0::IGnssCallback.GnssSvInfo v2_0;
+
+        /**
+         * Baseband Carrier-to-noise density in dB-Hz, typically in the range [0, 63]. It contains
+         * the measured C/N0 value for the signal measured at the baseband.
+         *
+         * This is typically a few dB weaker than the value estimated for C/N0 at the antenna port,
+         * which is reported in cN0DbHz.
+         *
+         * If a signal has separate components (e.g. Pilot and Data channels) and the receiver only
+         * processes one of the components, then the reported basebandCN0DbHz reflects only the
+         * component that is processed.
+         *
+         * This value is mandatory. Like cN0DbHz, it may be reported as 0 for satellites being
+         * reported that may be searched for, but not yet tracked.
+         */
+        double basebandCN0DbHz;
+    };
+
+    /**
+     * Callback for the HAL to pass a vector of GnssSvInfo back to the client.
+     *
+     * @param svInfoList SV info list information from HAL.
+     */
+    gnssSvStatusCb_2_1(vec<GnssSvInfo> svInfoList);
+};