n7100: some more GPS fixes

1 files changed, 1884 insertions, 0 deletions

diff --git a/include/hardware/gps.h b/include/hardware/gps.h
new file mode 100644
index 0000000..361e811
--- /dev/null
+++ b/include/hardware/gps.h
@@ -0,0 +1,1884 @@
+/*
+ * Copyright (C) 2010 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.
+ */
+
+#ifndef ANDROID_INCLUDE_HARDWARE_GPS_H
+#define ANDROID_INCLUDE_HARDWARE_GPS_H
+
+#include <stdint.h>
+#include <sys/cdefs.h>
+#include <sys/types.h>
+#include <pthread.h>
+#include <sys/socket.h>
+#include <stdbool.h>
+
+#include <hardware/hardware.h>
+
+__BEGIN_DECLS
+
+/**
+ * The id of this module
+ */
+#define GPS_HARDWARE_MODULE_ID "gps"
+
+
+/** Milliseconds since January 1, 1970 */
+typedef int64_t GpsUtcTime;
+
+/** Maximum number of SVs for gps_sv_status_callback(). */
+#define GPS_MAX_SVS 32
+
+/** Maximum number of Measurements in gps_measurement_callback(). */
+#define GPS_MAX_MEASUREMENT   32
+
+/** Requested operational mode for GPS operation. */
+typedef uint32_t GpsPositionMode;
+// IMPORTANT: Note that the following values must match
+// constants in GpsLocationProvider.java.
+/** Mode for running GPS standalone (no assistance). */
+#define GPS_POSITION_MODE_STANDALONE    0
+/** AGPS MS-Based mode. */
+#define GPS_POSITION_MODE_MS_BASED      1
+/**
+ * AGPS MS-Assisted mode. This mode is not maintained by the platform anymore.
+ * It is strongly recommended to use GPS_POSITION_MODE_MS_BASE instead.
+ */
+#define GPS_POSITION_MODE_MS_ASSISTED   2
+
+/** Requested recurrence mode for GPS operation. */
+typedef uint32_t GpsPositionRecurrence;
+// IMPORTANT: Note that the following values must match
+// constants in GpsLocationProvider.java.
+/** Receive GPS fixes on a recurring basis at a specified period. */
+#define GPS_POSITION_RECURRENCE_PERIODIC    0
+/** Request a single shot GPS fix. */
+#define GPS_POSITION_RECURRENCE_SINGLE      1
+
+/** GPS status event values. */
+typedef uint16_t GpsStatusValue;
+// IMPORTANT: Note that the following values must match
+// constants in GpsLocationProvider.java.
+/** GPS status unknown. */
+#define GPS_STATUS_NONE             0
+/** GPS has begun navigating. */
+#define GPS_STATUS_SESSION_BEGIN    1
+/** GPS has stopped navigating. */
+#define GPS_STATUS_SESSION_END      2
+/** GPS has powered on but is not navigating. */
+#define GPS_STATUS_ENGINE_ON        3
+/** GPS is powered off. */
+#define GPS_STATUS_ENGINE_OFF       4
+
+/** Flags to indicate which values are valid in a GpsLocation. */
+typedef uint16_t GpsLocationFlags;
+// IMPORTANT: Note that the following values must match
+// constants in GpsLocationProvider.java.
+/** GpsLocation has valid latitude and longitude. */
+#define GPS_LOCATION_HAS_LAT_LONG   0x0001
+/** GpsLocation has valid altitude. */
+#define GPS_LOCATION_HAS_ALTITUDE   0x0002
+/** GpsLocation has valid speed. */
+#define GPS_LOCATION_HAS_SPEED      0x0004
+/** GpsLocation has valid bearing. */
+#define GPS_LOCATION_HAS_BEARING    0x0008
+/** GpsLocation has valid accuracy. */
+#define GPS_LOCATION_HAS_ACCURACY   0x0010
+
+/** Flags for the gps_set_capabilities callback. */
+
+/** GPS HAL schedules fixes for GPS_POSITION_RECURRENCE_PERIODIC mode.
+    If this is not set, then the framework will use 1000ms for min_interval
+    and will start and call start() and stop() to schedule the GPS.
+ */
+#define GPS_CAPABILITY_SCHEDULING       0x0000001
+/** GPS supports MS-Based AGPS mode */
+#define GPS_CAPABILITY_MSB              0x0000002
+/** GPS supports MS-Assisted AGPS mode */
+#define GPS_CAPABILITY_MSA              0x0000004
+/** GPS supports single-shot fixes */
+#define GPS_CAPABILITY_SINGLE_SHOT      0x0000008
+/** GPS supports on demand time injection */
+#define GPS_CAPABILITY_ON_DEMAND_TIME   0x0000010
+/** GPS supports Geofencing  */
+#define GPS_CAPABILITY_GEOFENCING       0x0000020
+/** GPS supports Measurements */
+#define GPS_CAPABILITY_MEASUREMENTS     0x0000040
+/** GPS supports Navigation Messages */
+#define GPS_CAPABILITY_NAV_MESSAGES     0x0000080
+
+/** Flags used to specify which aiding data to delete
+    when calling delete_aiding_data(). */
+typedef uint16_t GpsAidingData;
+// IMPORTANT: Note that the following values must match
+// constants in GpsLocationProvider.java.
+#define GPS_DELETE_EPHEMERIS        0x0001
+#define GPS_DELETE_ALMANAC          0x0002
+#define GPS_DELETE_POSITION         0x0004
+#define GPS_DELETE_TIME             0x0008
+#define GPS_DELETE_IONO             0x0010
+#define GPS_DELETE_UTC              0x0020
+#define GPS_DELETE_HEALTH           0x0040
+#define GPS_DELETE_SVDIR            0x0080
+#define GPS_DELETE_SVSTEER          0x0100
+#define GPS_DELETE_SADATA           0x0200
+#define GPS_DELETE_RTI              0x0400
+#define GPS_DELETE_CELLDB_INFO      0x8000
+#define GPS_DELETE_ALL              0xFFFF
+
+/** AGPS type */
+typedef uint16_t AGpsType;
+#define AGPS_TYPE_SUPL          1
+#define AGPS_TYPE_C2K           2
+
+typedef uint16_t AGpsSetIDType;
+#define AGPS_SETID_TYPE_NONE    0
+#define AGPS_SETID_TYPE_IMSI    1
+#define AGPS_SETID_TYPE_MSISDN  2
+
+typedef uint16_t ApnIpType;
+#define APN_IP_INVALID          0
+#define APN_IP_IPV4             1
+#define APN_IP_IPV6             2
+#define APN_IP_IPV4V6           3
+
+/**
+ * String length constants
+ */
+#define GPS_NI_SHORT_STRING_MAXLEN      256
+#define GPS_NI_LONG_STRING_MAXLEN       2048
+
+/**
+ * GpsNiType constants
+ */
+typedef uint32_t GpsNiType;
+#define GPS_NI_TYPE_VOICE              1
+#define GPS_NI_TYPE_UMTS_SUPL          2
+#define GPS_NI_TYPE_UMTS_CTRL_PLANE    3
+
+/**
+ * GpsNiNotifyFlags constants
+ */
+typedef uint32_t GpsNiNotifyFlags;
+/** NI requires notification */
+#define GPS_NI_NEED_NOTIFY          0x0001
+/** NI requires verification */
+#define GPS_NI_NEED_VERIFY          0x0002
+/** NI requires privacy override, no notification/minimal trace */
+#define GPS_NI_PRIVACY_OVERRIDE     0x0004
+
+/**
+ * GPS NI responses, used to define the response in
+ * NI structures
+ */
+typedef int GpsUserResponseType;
+#define GPS_NI_RESPONSE_ACCEPT         1
+#define GPS_NI_RESPONSE_DENY           2
+#define GPS_NI_RESPONSE_NORESP         3
+
+/**
+ * NI data encoding scheme
+ */
+typedef int GpsNiEncodingType;
+#define GPS_ENC_NONE                   0
+#define GPS_ENC_SUPL_GSM_DEFAULT       1
+#define GPS_ENC_SUPL_UTF8              2
+#define GPS_ENC_SUPL_UCS2              3
+#define GPS_ENC_UNKNOWN                -1
+
+/** AGPS status event values. */
+typedef uint16_t AGpsStatusValue;
+/** GPS requests data connection for AGPS. */
+#define GPS_REQUEST_AGPS_DATA_CONN  1
+/** GPS releases the AGPS data connection. */
+#define GPS_RELEASE_AGPS_DATA_CONN  2
+/** AGPS data connection initiated */
+#define GPS_AGPS_DATA_CONNECTED     3
+/** AGPS data connection completed */
+#define GPS_AGPS_DATA_CONN_DONE     4
+/** AGPS data connection failed */
+#define GPS_AGPS_DATA_CONN_FAILED   5
+
+#define AGPS_REF_LOCATION_TYPE_GSM_CELLID   1
+#define AGPS_REF_LOCATION_TYPE_UMTS_CELLID  2
+#define AGPS_REG_LOCATION_TYPE_MAC          3
+
+/** Network types for update_network_state "type" parameter */
+#define AGPS_RIL_NETWORK_TYPE_MOBILE        0
+#define AGPS_RIL_NETWORK_TYPE_WIFI          1
+#define AGPS_RIL_NETWORK_TYPE_MOBILE_MMS    2
+#define AGPS_RIL_NETWORK_TYPE_MOBILE_SUPL   3
+#define AGPS_RIL_NETWORK_TTYPE_MOBILE_DUN   4
+#define AGPS_RIL_NETWORK_TTYPE_MOBILE_HIPRI 5
+#define AGPS_RIL_NETWORK_TTYPE_WIMAX        6
+
+/**
+ * Flags to indicate what fields in GpsClock are valid.
+ */
+typedef uint16_t GpsClockFlags;
+/** A valid 'leap second' is stored in the data structure. */
+#define GPS_CLOCK_HAS_LEAP_SECOND               (1<<0)
+/** A valid 'time uncertainty' is stored in the data structure. */
+#define GPS_CLOCK_HAS_TIME_UNCERTAINTY          (1<<1)
+/** A valid 'full bias' is stored in the data structure. */
+#define GPS_CLOCK_HAS_FULL_BIAS                 (1<<2)
+/** A valid 'bias' is stored in the data structure. */
+#define GPS_CLOCK_HAS_BIAS                      (1<<3)
+/** A valid 'bias uncertainty' is stored in the data structure. */
+#define GPS_CLOCK_HAS_BIAS_UNCERTAINTY          (1<<4)
+/** A valid 'drift' is stored in the data structure. */
+#define GPS_CLOCK_HAS_DRIFT                     (1<<5)
+/** A valid 'drift uncertainty' is stored in the data structure. */
+#define GPS_CLOCK_HAS_DRIFT_UNCERTAINTY         (1<<6)
+
+/**
+ * Enumeration of the available values for the GPS Clock type.
+ */
+typedef uint8_t GpsClockType;
+/** The type is not available ot it is unknown. */
+#define GPS_CLOCK_TYPE_UNKNOWN                  0
+/** The source of the time value reported by GPS clock is the local hardware clock. */
+#define GPS_CLOCK_TYPE_LOCAL_HW_TIME            1
+/**
+ * The source of the time value reported by GPS clock is the GPS time derived from satellites
+ * (epoch = Jan 6, 1980)
+ */
+#define GPS_CLOCK_TYPE_GPS_TIME                 2
+
+/**
+ * Flags to indicate what fields in GpsMeasurement are valid.
+ */
+typedef uint32_t GpsMeasurementFlags;
+/** A valid 'snr' is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_SNR                               (1<<0)
+/** A valid 'elevation' is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_ELEVATION                         (1<<1)
+/** A valid 'elevation uncertainty' is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_ELEVATION_UNCERTAINTY             (1<<2)
+/** A valid 'azimuth' is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_AZIMUTH                           (1<<3)
+/** A valid 'azimuth uncertainty' is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_AZIMUTH_UNCERTAINTY               (1<<4)
+/** A valid 'pseudorange' is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_PSEUDORANGE                       (1<<5)
+/** A valid 'pseudorange uncertainty' is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_PSEUDORANGE_UNCERTAINTY           (1<<6)
+/** A valid 'code phase' is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_CODE_PHASE                        (1<<7)
+/** A valid 'code phase uncertainty' is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_CODE_PHASE_UNCERTAINTY            (1<<8)
+/** A valid 'carrier frequency' is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_CARRIER_FREQUENCY                 (1<<9)
+/** A valid 'carrier cycles' is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_CARRIER_CYCLES                    (1<<10)
+/** A valid 'carrier phase' is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_CARRIER_PHASE                     (1<<11)
+/** A valid 'carrier phase uncertainty' is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_CARRIER_PHASE_UNCERTAINTY         (1<<12)
+/** A valid 'bit number' is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_BIT_NUMBER                        (1<<13)
+/** A valid 'time from last bit' is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_TIME_FROM_LAST_BIT                (1<<14)
+/** A valid 'doppler shift' is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_DOPPLER_SHIFT                     (1<<15)
+/** A valid 'doppler shift uncertainty' is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_DOPPLER_SHIFT_UNCERTAINTY         (1<<16)
+/** A valid 'used in fix' flag is stored in the data structure. */
+#define GPS_MEASUREMENT_HAS_USED_IN_FIX                       (1<<17)
+/** The value of 'pseudorange rate' is uncorrected. */
+#define GPS_MEASUREMENT_HAS_UNCORRECTED_PSEUDORANGE_RATE      (1<<18)
+
+/**
+ * Enumeration of the available values for the GPS Measurement's loss of lock.
+ */
+typedef uint8_t GpsLossOfLock;
+/** The indicator is not available or it is unknown. */
+#define GPS_LOSS_OF_LOCK_UNKNOWN                            0
+/** The measurement does not present any indication of loss of lock. */
+#define GPS_LOSS_OF_LOCK_OK                                 1
+/** Loss of lock between previous and current observation: cycle slip possible. */
+#define GPS_LOSS_OF_LOCK_CYCLE_SLIP                         2
+
+/**
+ * Enumeration of available values for the GPS Measurement's multipath indicator.
+ */
+typedef uint8_t GpsMultipathIndicator;
+/** The indicator is not available or unknown. */
+#define GPS_MULTIPATH_INDICATOR_UNKNOWN                 0
+/** The measurement has been indicated to use multipath. */
+#define GPS_MULTIPATH_INDICATOR_DETECTED                1
+/** The measurement has been indicated Not to use multipath. */
+#define GPS_MULTIPATH_INDICATOR_NOT_USED                2
+
+/**
+ * Flags indicating the GPS measurement state.
+ * The expected behavior here is for GPS HAL to set all the flags that applies. For
+ * example, if the state for a satellite is only C/A code locked and bit synchronized,
+ * and there is still millisecond ambiguity, the state should be set as:
+ * GPS_MEASUREMENT_STATE_CODE_LOCK|GPS_MEASUREMENT_STATE_BIT_SYNC|GPS_MEASUREMENT_STATE_MSEC_AMBIGUOUS
+ * If GPS is still searching for a satellite, the corresponding state should be set to
+ * GPS_MEASUREMENT_STATE_UNKNOWN(0).
+ */
+typedef uint16_t GpsMeasurementState;
+#define GPS_MEASUREMENT_STATE_UNKNOWN                   0
+#define GPS_MEASUREMENT_STATE_CODE_LOCK             (1<<0)
+#define GPS_MEASUREMENT_STATE_BIT_SYNC              (1<<1)
+#define GPS_MEASUREMENT_STATE_SUBFRAME_SYNC         (1<<2)
+#define GPS_MEASUREMENT_STATE_TOW_DECODED           (1<<3)
+#define GPS_MEASUREMENT_STATE_MSEC_AMBIGUOUS        (1<<4)
+
+/**
+ * Flags indicating the Accumulated Delta Range's states.
+ */
+typedef uint16_t GpsAccumulatedDeltaRangeState;
+#define GPS_ADR_STATE_UNKNOWN                       0
+#define GPS_ADR_STATE_VALID                     (1<<0)
+#define GPS_ADR_STATE_RESET                     (1<<1)
+#define GPS_ADR_STATE_CYCLE_SLIP                (1<<2)
+
+/**
+ * Enumeration of available values to indicate the available GPS Navigation message types.
+ */
+typedef uint8_t GpsNavigationMessageType;
+/** The message type is unknown. */
+#define GPS_NAVIGATION_MESSAGE_TYPE_UNKNOWN         0
+/** L1 C/A message contained in the structure.  */
+#define GPS_NAVIGATION_MESSAGE_TYPE_L1CA            1
+/** L2-CNAV message contained in the structure. */
+#define GPS_NAVIGATION_MESSAGE_TYPE_L2CNAV          2
+/** L5-CNAV message contained in the structure. */
+#define GPS_NAVIGATION_MESSAGE_TYPE_L5CNAV          3
+/** CNAV-2 message contained in the structure. */
+#define GPS_NAVIGATION_MESSAGE_TYPE_CNAV2           4
+
+/**
+ * Status of Navigation Message
+ * When a message is received properly without any parity error in its navigation words, the
+ * status should be set to NAV_MESSAGE_STATUS_PARITY_PASSED. But if a message is received
+ * with words that failed parity check, but GPS is able to correct those words, the status
+ * should be set to NAV_MESSAGE_STATUS_PARITY_REBUILT.
+ * No need to send any navigation message that contains words with parity error and cannot be
+ * corrected.
+ */
+typedef uint16_t NavigationMessageStatus;
+#define NAV_MESSAGE_STATUS_UNKONW              0
+#define NAV_MESSAGE_STATUS_PARITY_PASSED   (1<<0)
+#define NAV_MESSAGE_STATUS_PARITY_REBUILT  (1<<1)
+
+/**
+ * Name for the GPS XTRA interface.
+ */
+#define GPS_XTRA_INTERFACE      "gps-xtra"
+
+/**
+ * Name for the GPS DEBUG interface.
+ */
+#define GPS_DEBUG_INTERFACE      "gps-debug"
+
+/**
+ * Name for the AGPS interface.
+ */
+#define AGPS_INTERFACE      "agps"
+
+/**
+ * Name of the Supl Certificate interface.
+ */
+#define SUPL_CERTIFICATE_INTERFACE  "supl-certificate"
+
+/**
+ * Name for NI interface
+ */
+#define GPS_NI_INTERFACE "gps-ni"
+
+/**
+ * Name for the AGPS-RIL interface.
+ */
+#define AGPS_RIL_INTERFACE      "agps_ril"
+
+/**
+ * The GPS chipset can use Psc for AGPS.
+ */
+#define AGPS_USE_PSC
+
+/**
+ * Name for the GPS_Geofencing interface.
+ */
+#define GPS_GEOFENCING_INTERFACE   "gps_geofencing"
+
+/**
+ * Name of the GPS Measurements interface.
+ */
+#define GPS_MEASUREMENT_INTERFACE   "gps_measurement"
+
+/**
+ * Name of the GPS navigation message interface.
+ */
+#define GPS_NAVIGATION_MESSAGE_INTERFACE     "gps_navigation_message"
+
+/**
+ * Name of the GNSS/GPS configuration interface.
+ */
+#define GNSS_CONFIGURATION_INTERFACE     "gnss_configuration"
+
+
+/** Represents a location. */
+typedef struct {
+    /** set to sizeof(GpsLocation) */
+    size_t          size;
+    /** Contains GpsLocationFlags bits. */
+    uint16_t        flags;
+    /** Represents latitude in degrees. */
+    double          latitude;
+    /** Represents longitude in degrees. */
+    double          longitude;
+    /** Represents altitude in meters above the WGS 84 reference
+     * ellipsoid. */
+    double          altitude;
+    /** Represents speed in meters per second. */
+    float           speed;
+    /** Represents heading in degrees. */
+    float           bearing;
+    /** Represents expected accuracy in meters. */
+    float           accuracy;
+    /** Timestamp for the location fix. */
+    GpsUtcTime      timestamp;
+} GpsLocation;
+
+/** Represents the status. */
+typedef struct {
+    /** set to sizeof(GpsStatus) */
+    size_t          size;
+    GpsStatusValue status;
+} GpsStatus;
+
+/** Represents SV information. */
+typedef struct {
+    /** set to sizeof(GpsSvInfo) */
+    size_t          size;
+    /** Pseudo-random number for the SV. */
+    int     prn;
+    /** Signal to noise ratio. */
+    float   snr;
+    /** Elevation of SV in degrees. */
+    float   elevation;
+    /** Azimuth of SV in degrees. */
+    float   azimuth;
+    /** Unknown field in Samsung I9100 libgps
+        May be an indicator for constellation type
+        (GPS, GLONASS, Galileo)?
+        Used on GT-I9100, likely also present on GT-N7000,
+        SGH-I717, SGH-I727 but this needs confirmation.
+    */
+    int unknown_samsung_field;
+} GpsSvInfo;
+
+/** Represents SV status. */
+typedef struct {
+    /** set to sizeof(GpsSvStatus) */
+    size_t          size;
+
+    /** Number of SVs currently visible. */
+    int         num_svs;
+
+    /** Contains an array of SV information. */
+    GpsSvInfo   sv_list[GPS_MAX_SVS];
+
+    /** Represents a bit mask indicating which SVs
+     * have ephemeris data.
+     */
+    uint32_t    ephemeris_mask;
+
+    /** Represents a bit mask indicating which SVs
+     * have almanac data.
+     */
+    uint32_t    almanac_mask;
+
+    /**
+     * Represents a bit mask indicating which SVs
+     * were used for computing the most recent position fix.
+     */
+    uint32_t    used_in_fix_mask;
+} GpsSvStatus;
+
+
+/* 2G and 3G */
+/* In 3G lac is discarded */
+typedef struct {
+    uint16_t type;
+    uint16_t mcc;
+    uint16_t mnc;
+    uint16_t lac;
+#ifdef AGPS_USE_PSC
+    uint16_t psc;
+#endif
+    uint32_t cid;
+} AGpsRefLocationCellID;
+
+typedef struct {
+    uint8_t mac[6];
+} AGpsRefLocationMac;
+
+/** Represents ref locations */
+typedef struct {
+    uint16_t type;
+    union {
+        AGpsRefLocationCellID   cellID;
+        AGpsRefLocationMac      mac;
+    } u;
+} AGpsRefLocation;
+
+/** Callback with location information.
+ *  Can only be called from a thread created by create_thread_cb.
+ */
+typedef void (* gps_location_callback)(GpsLocation* location);
+
+/** Callback with status information.
+ *  Can only be called from a thread created by create_thread_cb.
+ */
+typedef void (* gps_status_callback)(GpsStatus* status);
+
+/**
+ * Callback with SV status information.
+ * Can only be called from a thread created by create_thread_cb.
+ */
+typedef void (* gps_sv_status_callback)(GpsSvStatus* sv_info);
+
+/** Callback for reporting NMEA sentences.
+ *  Can only be called from a thread created by create_thread_cb.
+ */
+typedef void (* gps_nmea_callback)(GpsUtcTime timestamp, const char* nmea, int length);
+
+/** Callback to inform framework of the GPS engine's capabilities.
+ *  Capability parameter is a bit field of GPS_CAPABILITY_* flags.
+ */
+typedef void (* gps_set_capabilities)(uint32_t capabilities);
+
+/** Callback utility for acquiring the GPS wakelock.
+ *  This can be used to prevent the CPU from suspending while handling GPS events.
+ */
+typedef void (* gps_acquire_wakelock)();
+
+/** Callback utility for releasing the GPS wakelock. */
+typedef void (* gps_release_wakelock)();
+
+/** Callback for requesting NTP time */
+typedef void (* gps_request_utc_time)();
+
+/** Callback for creating a thread that can call into the Java framework code.
+ *  This must be used to create any threads that report events up to the framework.
+ */
+typedef pthread_t (* gps_create_thread)(const char* name, void (*start)(void *), void* arg);
+
+/** GPS callback structure. */
+typedef struct {
+    /** set to sizeof(GpsCallbacks) */
+    size_t      size;
+    gps_location_callback location_cb;
+    gps_status_callback status_cb;
+    gps_sv_status_callback sv_status_cb;
+    gps_nmea_callback nmea_cb;
+    gps_set_capabilities set_capabilities_cb;
+    gps_acquire_wakelock acquire_wakelock_cb;
+    gps_release_wakelock release_wakelock_cb;
+    gps_create_thread create_thread_cb;
+    gps_request_utc_time request_utc_time_cb;
+} GpsCallbacks;
+
+
+/** Represents the standard GPS interface. */
+typedef struct {
+    /** set to sizeof(GpsInterface) */
+    size_t          size;
+    /**
+     * Opens the interface and provides the callback routines
+     * to the implementation of this interface.
+     */
+    int   (*init)( GpsCallbacks* callbacks );
+
+    /** Starts navigating. */
+    int   (*start)( void );
+
+    /** Stops navigating. */
+    int   (*stop)( void );
+
+    /** Closes the interface. */
+    void  (*cleanup)( void );
+
+    /** Injects the current time. */
+    int   (*inject_time)(GpsUtcTime time, int64_t timeReference,
+                         int uncertainty);
+
+    /** Injects current location from another location provider
+     *  (typically cell ID).
+     *  latitude and longitude are measured in degrees
+     *  expected accuracy is measured in meters
+     */
+    int  (*inject_location)(double latitude, double longitude, float accuracy);
+
+    /**
+     * Specifies that the next call to start will not use the
+     * information defined in the flags. GPS_DELETE_ALL is passed for
+     * a cold start.
+     */
+    void  (*delete_aiding_data)(GpsAidingData flags);
+
+    /**
+     * min_interval represents the time between fixes in milliseconds.
+     * preferred_accuracy represents the requested fix accuracy in meters.
+     * preferred_time represents the requested time to first fix in milliseconds.
+     *
+     * 'mode' parameter should be one of GPS_POSITION_MODE_MS_BASE
+     * or GPS_POSITION_MODE_STANDALONE.
+     * It is allowed by the platform (and it is recommended) to fallback to
+     * GPS_POSITION_MODE_MS_BASE if GPS_POSITION_MODE_MS_ASSISTED is passed in, and
+     * GPS_POSITION_MODE_MS_BASED is supported.
+     */
+    int   (*set_position_mode)(GpsPositionMode mode, GpsPositionRecurrence recurrence,
+            uint32_t min_interval, uint32_t preferred_accuracy, uint32_t preferred_time);
+
+    /** Get a pointer to extension information. */
+    const void* (*get_extension)(const char* name);
+} GpsInterface;
+
+/** Callback to request the client to download XTRA data.
+ *  The client should download XTRA data and inject it by calling inject_xtra_data().
+ *  Can only be called from a thread created by create_thread_cb.
+ */
+typedef void (* gps_xtra_download_request)();
+
+/** Callback structure for the XTRA interface. */
+typedef struct {
+    gps_xtra_download_request download_request_cb;
+    gps_create_thread create_thread_cb;
+} GpsXtraCallbacks;
+
+/** Extended interface for XTRA support. */
+typedef struct {
+    /** set to sizeof(GpsXtraInterface) */
+    size_t          size;
+    /**
+     * Opens the XTRA interface and provides the callback routines
+     * to the implementation of this interface.
+     */
+    int  (*init)( GpsXtraCallbacks* callbacks );
+    /** Injects XTRA data into the GPS. */
+    int  (*inject_xtra_data)( char* data, int length );
+} GpsXtraInterface;
+
+/** Extended interface for DEBUG support. */
+typedef struct {
+    /** set to sizeof(GpsDebugInterface) */
+    size_t          size;
+
+    /**
+     * This function should return any information that the native
+     * implementation wishes to include in a bugreport.
+     */
+    size_t (*get_internal_state)(char* buffer, size_t bufferSize);
+} GpsDebugInterface;
+
+#pragma pack(push,4)
+// We need to keep the alignment of this data structure to 4-bytes, to ensure that in 64-bit
+// environments the size of this legacy definition does not collide with _v2. Implementations should
+// be using _v2 and _v3, so it's OK to pay the 'unaligned' penalty in 64-bit if an old
+// implementation is still in use.
+
+/** Represents the status of AGPS. */
+typedef struct {
+    /** set to sizeof(AGpsStatus_v1) */
+    size_t          size;
+
+    AGpsType        type;
+    AGpsStatusValue status;
+} AGpsStatus_v1;
+
+#pragma pack(pop)
+
+/** Represents the status of AGPS augmented with a IPv4 address field. */
+typedef struct {
+    /** set to sizeof(AGpsStatus_v2) */
+    size_t          size;
+
+    AGpsType        type;
+    AGpsStatusValue status;
+    uint32_t        ipaddr;
+} AGpsStatus_v2;
+
+/* Represents the status of AGPS augmented to support IPv4 and IPv6. */
+typedef struct {
+    /** set to sizeof(AGpsStatus_v3) */
+    size_t                  size;
+
+    AGpsType                type;
+    AGpsStatusValue         status;
+
+    /**
+     * Must be set to a valid IPv4 address if the field 'addr' contains an IPv4
+     * address, or set to INADDR_NONE otherwise.
+     */
+    uint32_t                ipaddr;
+
+    /**
+     * Must contain the IPv4 (AF_INET) or IPv6 (AF_INET6) address to report.
+     * Any other value of addr.ss_family will be rejected.
+     * */
+    struct sockaddr_storage addr;
+} AGpsStatus_v3;
+
+typedef AGpsStatus_v3     AGpsStatus;
+
+/** Callback with AGPS status information.
+ *  Can only be called from a thread created by create_thread_cb.
+ */
+typedef void (* agps_status_callback)(AGpsStatus* status);
+
+/** Callback structure for the AGPS interface. */
+typedef struct {
+    agps_status_callback status_cb;
+    gps_create_thread create_thread_cb;
+} AGpsCallbacks;
+
+
+/** Extended interface for AGPS support. */
+typedef struct {
+    /** set to sizeof(AGpsInterface_v1) */
+    size_t          size;
+
+    /**
+     * Opens the AGPS interface and provides the callback routines
+     * to the implementation of this interface.
+     */
+    void  (*init)( AGpsCallbacks* callbacks );
+    /**
+     * Notifies that a data connection is available and sets
+     * the name of the APN to be used for SUPL.
+     */
+    int  (*data_conn_open)( const char* apn );
+    /**
+     * Notifies that the AGPS data connection has been closed.
+     */
+    int  (*data_conn_closed)();
+    /**
+     * Notifies that a data connection is not available for AGPS.
+     */
+    int  (*data_conn_failed)();
+    /**
+     * Sets the hostname and port for the AGPS server.
+     */
+    int  (*set_server)( AGpsType type, const char* hostname, int port );
+} AGpsInterface_v1;
+
+/**
+ * Extended interface for AGPS support, it is augmented to enable to pass
+ * extra APN data.
+ */
+typedef struct {
+    /** set to sizeof(AGpsInterface_v2) */
+    size_t size;
+
+    /**
+     * Opens the AGPS interface and provides the callback routines to the
+     * implementation of this interface.
+     */
+    void (*init)(AGpsCallbacks* callbacks);
+    /**
+     * Deprecated.
+     * If the HAL supports AGpsInterface_v2 this API will not be used, see
+     * data_conn_open_with_apn_ip_type for more information.
+     */
+    int (*data_conn_open)(const char* apn);
+    /**
+     * Notifies that the AGPS data connection has been closed.
+     */
+    int (*data_conn_closed)();
+    /**
+     * Notifies that a data connection is not available for AGPS.
+     */
+    int (*data_conn_failed)();
+    /**
+     * Sets the hostname and port for the AGPS server.
+     */
+    int (*set_server)(AGpsType type, const char* hostname, int port);
+
+    /**
+     * Notifies that a data connection is available and sets the name of the
+     * APN, and its IP type, to be used for SUPL connections.
+     */
+    int (*data_conn_open_with_apn_ip_type)(
+            const char* apn,
+            ApnIpType apnIpType);
+} AGpsInterface_v2;
+
+typedef AGpsInterface_v2    AGpsInterface;
+
+/** Error codes associated with certificate operations */
+#define AGPS_CERTIFICATE_OPERATION_SUCCESS               0
+#define AGPS_CERTIFICATE_ERROR_GENERIC                -100
+#define AGPS_CERTIFICATE_ERROR_TOO_MANY_CERTIFICATES  -101
+
+/** A data structure that represents an X.509 certificate using DER encoding */
+typedef struct {
+    size_t  length;
+    u_char* data;
+} DerEncodedCertificate;
+
+/**
+ * A type definition for SHA1 Fingerprints used to identify X.509 Certificates
+ * The Fingerprint is a digest of the DER Certificate that uniquely identifies it.
+ */
+typedef struct {
+    u_char data[20];
+} Sha1CertificateFingerprint;
+
+/** AGPS Interface to handle SUPL certificate operations */
+typedef struct {
+    /** set to sizeof(SuplCertificateInterface) */
+    size_t size;
+
+    /**
+     * Installs a set of Certificates used for SUPL connections to the AGPS server.
+     * If needed the HAL should find out internally any certificates that need to be removed to
+     * accommodate the certificates to install.
+     * The certificates installed represent a full set of valid certificates needed to connect to
+     * AGPS SUPL servers.
+     * The list of certificates is required, and all must be available at the same time, when trying
+     * to establish a connection with the AGPS Server.
+     *
+     * Parameters:
+     *      certificates - A pointer to an array of DER encoded certificates that are need to be
+     *                     installed in the HAL.
+     *      length - The number of certificates to install.
+     * Returns:
+     *      AGPS_CERTIFICATE_OPERATION_SUCCESS if the operation is completed successfully
+     *      AGPS_CERTIFICATE_ERROR_TOO_MANY_CERTIFICATES if the HAL cannot store the number of
+     *          certificates attempted to be installed, the state of the certificates stored should
+     *          remain the same as before on this error case.
+     *
+     * IMPORTANT:
+     *      If needed the HAL should find out internally the set of certificates that need to be
+     *      removed to accommodate the certificates to install.
+     */
+    int  (*install_certificates) ( const DerEncodedCertificate* certificates, size_t length );
+
+    /**
+     * Notifies the HAL that a list of certificates used for SUPL connections are revoked. It is
+     * expected that the given set of certificates is removed from the internal store of the HAL.
+     *
+     * Parameters:
+     *      fingerprints - A pointer to an array of SHA1 Fingerprints to identify the set of
+     *                     certificates to revoke.
+     *      length - The number of fingerprints provided.
+     * Returns:
+     *      AGPS_CERTIFICATE_OPERATION_SUCCESS if the operation is completed successfully.
+     *
+     * IMPORTANT:
+     *      If any of the certificates provided (through its fingerprint) is not known by the HAL,
+     *      it should be ignored and continue revoking/deleting the rest of them.
+     */
+    int  (*revoke_certificates) ( const Sha1CertificateFingerprint* fingerprints, size_t length );
+} SuplCertificateInterface;
+
+/** Represents an NI request */
+typedef struct {
+    /** set to sizeof(GpsNiNotification) */
+    size_t          size;
+
+    /**
+     * An ID generated by HAL to associate NI notifications and UI
+     * responses
+     */
+    int             notification_id;
+
+    /**
+     * An NI type used to distinguish different categories of NI
+     * events, such as GPS_NI_TYPE_VOICE, GPS_NI_TYPE_UMTS_SUPL, ...
+     */
+    GpsNiType       ni_type;
+
+    /**
+     * Notification/verification options, combinations of GpsNiNotifyFlags constants
+     */
+    GpsNiNotifyFlags notify_flags;
+
+    /**
+     * Timeout period to wait for user response.
+     * Set to 0 for no time out limit.
+     */
+    int             timeout;
+
+    /**
+     * Default response when time out.
+     */
+    GpsUserResponseType default_response;
+
+    /**
+     * Requestor ID
+     */
+    char            requestor_id[GPS_NI_SHORT_STRING_MAXLEN];
+
+    /**
+     * Notification message. It can also be used to store client_id in some cases
+     */
+    char            text[GPS_NI_LONG_STRING_MAXLEN];
+
+    /**
+     * Client name decoding scheme
+     */
+    GpsNiEncodingType requestor_id_encoding;
+
+    /**
+     * Client name decoding scheme
+     */
+    GpsNiEncodingType text_encoding;
+
+    /**
+     * A pointer to extra data. Format:
+     * key_1 = value_1
+     * key_2 = value_2
+     */
+    char           extras[GPS_NI_LONG_STRING_MAXLEN];
+
+} GpsNiNotification;
+
+/** Callback with NI notification.
+ *  Can only be called from a thread created by create_thread_cb.
+ */
+typedef void (*gps_ni_notify_callback)(GpsNiNotification *notification);
+
+/** GPS NI callback structure. */
+typedef struct
+{
+    /**
+     * Sends the notification request from HAL to GPSLocationProvider.
+     */
+    gps_ni_notify_callback notify_cb;
+    gps_create_thread create_thread_cb;
+} GpsNiCallbacks;
+
+/**
+ * Extended interface for Network-initiated (NI) support.
+ */
+typedef struct
+{
+    /** set to sizeof(GpsNiInterface) */
+    size_t          size;
+
+   /** Registers the callbacks for HAL to use. */
+   void (*init) (GpsNiCallbacks *callbacks);
+
+   /** Sends a response to HAL. */
+   void (*respond) (int notif_id, GpsUserResponseType user_response);
+} GpsNiInterface;
+
+struct gps_device_t {
+    struct hw_device_t common;
+
+    /**
+     * Set the provided lights to the provided values.
+     *
+     * Returns: 0 on succes, error code on failure.
+     */
+    const GpsInterface* (*get_gps_interface)(struct gps_device_t* dev);
+};
+
+#define AGPS_RIL_REQUEST_SETID_IMSI     (1<<0L)
+#define AGPS_RIL_REQUEST_SETID_MSISDN   (1<<1L)
+
+#define AGPS_RIL_REQUEST_REFLOC_CELLID  (1<<0L)
+#define AGPS_RIL_REQUEST_REFLOC_MAC     (1<<1L)
+
+typedef void (*agps_ril_request_set_id)(uint32_t flags);
+typedef void (*agps_ril_request_ref_loc)(uint32_t flags);
+
+typedef struct {
+    agps_ril_request_set_id request_setid;
+    agps_ril_request_ref_loc request_refloc;
+    gps_create_thread create_thread_cb;
+} AGpsRilCallbacks;
+
+/** Extended interface for AGPS_RIL support. */
+typedef struct {
+    /** set to sizeof(AGpsRilInterface) */
+    size_t          size;
+    /**
+     * Opens the AGPS interface and provides the callback routines
+     * to the implementation of this interface.
+     */
+    void  (*init)( AGpsRilCallbacks* callbacks );
+
+    /**
+     * Sets the reference location.
+     */
+    void (*set_ref_location) (const AGpsRefLocation *agps_reflocation, size_t sz_struct);
+    /**
+     * Sets the set ID.
+     */
+    void (*set_set_id) (AGpsSetIDType type, const char* setid);
+
+    /**
+     * Send network initiated message.
+     */
+    void (*ni_message) (uint8_t *msg, size_t len);
+
+    /**
+     * Notify GPS of network status changes.
+     * These parameters match values in the android.net.NetworkInfo class.
+     */
+    void (*update_network_state) (int connected, int type, int roaming, const char* extra_info);
+
+    /**
+     * Notify GPS of network status changes.
+     * These parameters match values in the android.net.NetworkInfo class.
+     */
+    void (*update_network_availability) (int avaiable, const char* apn);
+} AGpsRilInterface;
+
+/**
+ * GPS Geofence.
+ *      There are 3 states associated with a Geofence: Inside, Outside, Unknown.
+ * There are 3 transitions: ENTERED, EXITED, UNCERTAIN.
+ *
+ * An example state diagram with confidence level: 95% and Unknown time limit
+ * set as 30 secs is shown below. (confidence level and Unknown time limit are
+ * explained latter)
+ *                         ____________________________
+ *                        |       Unknown (30 secs)   |
+ *                         """"""""""""""""""""""""""""
+ *                            ^ |                  |  ^
+ *                   UNCERTAIN| |ENTERED     EXITED|  |UNCERTAIN
+ *                            | v                  v  |
+ *                        ________    EXITED     _________
+ *                       | Inside | -----------> | Outside |
+ *                       |        | <----------- |         |
+ *                        """"""""    ENTERED    """""""""
+ *
+ * Inside state: We are 95% confident that the user is inside the geofence.
+ * Outside state: We are 95% confident that the user is outside the geofence
+ * Unknown state: Rest of the time.
+ *
+ * The Unknown state is better explained with an example:
+ *
+ *                            __________
+ *                           |         c|
+ *                           |  ___     |    _______
+ *                           |  |a|     |   |   b   |
+ *                           |  """     |    """""""
+ *                           |          |
+ *                            """"""""""
+ * In the diagram above, "a" and "b" are 2 geofences and "c" is the accuracy
+ * circle reported by the GPS subsystem. Now with regard to "b", the system is
+ * confident that the user is outside. But with regard to "a" is not confident
+ * whether it is inside or outside the geofence. If the accuracy remains the
+ * same for a sufficient period of time, the UNCERTAIN transition would be
+ * triggered with the state set to Unknown. If the accuracy improves later, an
+ * appropriate transition should be triggered.  This "sufficient period of time"
+ * is defined by the parameter in the add_geofence_area API.
+ *     In other words, Unknown state can be interpreted as a state in which the
+ * GPS subsystem isn't confident enough that the user is either inside or
+ * outside the Geofence. It moves to Unknown state only after the expiry of the
+ * timeout.
+ *
+ * The geofence callback needs to be triggered for the ENTERED and EXITED
+ * transitions, when the GPS system is confident that the user has entered
+ * (Inside state) or exited (Outside state) the Geofence. An implementation
+ * which uses a value of 95% as the confidence is recommended. The callback
+ * should be triggered only for the transitions requested by the
+ * add_geofence_area call.
+ *
+ * Even though the diagram and explanation talks about states and transitions,
+ * the callee is only interested in the transistions. The states are mentioned
+ * here for illustrative purposes.
+ *
+ * Startup Scenario: When the device boots up, if an application adds geofences,
+ * and then we get an accurate GPS location fix, it needs to trigger the
+ * appropriate (ENTERED or EXITED) transition for every Geofence it knows about.
+ * By default, all the Geofences will be in the Unknown state.
+ *
+ * When the GPS system is unavailable, gps_geofence_status_callback should be
+ * called to inform the upper layers of the same. Similarly, when it becomes
+ * available the callback should be called. This is a global state while the
+ * UNKNOWN transition described above is per geofence.
+ *
+ * An important aspect to note is that users of this API (framework), will use
+ * other subsystems like wifi, sensors, cell to handle Unknown case and
+ * hopefully provide a definitive state transition to the third party
+ * application. GPS Geofence will just be a signal indicating what the GPS
+ * subsystem knows about the Geofence.
+ *
+ */
+#define GPS_GEOFENCE_ENTERED     (1<<0L)
+#define GPS_GEOFENCE_EXITED      (1<<1L)
+#define GPS_GEOFENCE_UNCERTAIN   (1<<2L)
+
+#define GPS_GEOFENCE_UNAVAILABLE (1<<0L)
+#define GPS_GEOFENCE_AVAILABLE   (1<<1L)
+
+#define GPS_GEOFENCE_OPERATION_SUCCESS           0
+#define GPS_GEOFENCE_ERROR_TOO_MANY_GEOFENCES -100
+#define GPS_GEOFENCE_ERROR_ID_EXISTS          -101
+#define GPS_GEOFENCE_ERROR_ID_UNKNOWN         -102
+#define GPS_GEOFENCE_ERROR_INVALID_TRANSITION -103
+#define GPS_GEOFENCE_ERROR_GENERIC            -149
+
+/**
+ * The callback associated with the geofence.
+ * Parameters:
+ *      geofence_id - The id associated with the add_geofence_area.
+ *      location    - The current GPS location.
+ *      transition  - Can be one of GPS_GEOFENCE_ENTERED, GPS_GEOFENCE_EXITED,
+ *                    GPS_GEOFENCE_UNCERTAIN.
+ *      timestamp   - Timestamp when the transition was detected.
+ *
+ * The callback should only be called when the caller is interested in that
+ * particular transition. For instance, if the caller is interested only in
+ * ENTERED transition, then the callback should NOT be called with the EXITED
+ * transition.
+ *
+ * IMPORTANT: If a transition is triggered resulting in this callback, the GPS
+ * subsystem will wake up the application processor, if its in suspend state.
+ */
+typedef void (*gps_geofence_transition_callback) (int32_t geofence_id,  GpsLocation* location,
+        int32_t transition, GpsUtcTime timestamp);
+
+/**
+ * The callback associated with the availability of the GPS system for geofencing
+ * monitoring. If the GPS system determines that it cannot monitor geofences
+ * because of lack of reliability or unavailability of the GPS signals, it will
+ * call this callback with GPS_GEOFENCE_UNAVAILABLE parameter.
+ *
+ * Parameters:
+ *  status - GPS_GEOFENCE_UNAVAILABLE or GPS_GEOFENCE_AVAILABLE.
+ *  last_location - Last known location.
+ */
+typedef void (*gps_geofence_status_callback) (int32_t status, GpsLocation* last_location);
+
+/**
+ * The callback associated with the add_geofence call.
+ *
+ * Parameter:
+ * geofence_id - Id of the geofence.
+ * status - GPS_GEOFENCE_OPERATION_SUCCESS
+ *          GPS_GEOFENCE_ERROR_TOO_MANY_GEOFENCES  - geofence limit has been reached.
+ *          GPS_GEOFENCE_ERROR_ID_EXISTS  - geofence with id already exists
+ *          GPS_GEOFENCE_ERROR_INVALID_TRANSITION - the monitorTransition contains an
+ *              invalid transition
+ *          GPS_GEOFENCE_ERROR_GENERIC - for other errors.
+ */
+typedef void (*gps_geofence_add_callback) (int32_t geofence_id, int32_t status);
+
+/**
+ * The callback associated with the remove_geofence call.
+ *
+ * Parameter:
+ * geofence_id - Id of the geofence.
+ * status - GPS_GEOFENCE_OPERATION_SUCCESS
+ *          GPS_GEOFENCE_ERROR_ID_UNKNOWN - for invalid id
+ *          GPS_GEOFENCE_ERROR_GENERIC for others.
+ */
+typedef void (*gps_geofence_remove_callback) (int32_t geofence_id, int32_t status);
+
+
+/**
+ * The callback associated with the pause_geofence call.
+ *
+ * Parameter:
+ * geofence_id - Id of the geofence.
+ * status - GPS_GEOFENCE_OPERATION_SUCCESS
+ *          GPS_GEOFENCE_ERROR_ID_UNKNOWN - for invalid id
+ *          GPS_GEOFENCE_ERROR_INVALID_TRANSITION -
+ *                    when monitor_transitions is invalid
+ *          GPS_GEOFENCE_ERROR_GENERIC for others.
+ */
+typedef void (*gps_geofence_pause_callback) (int32_t geofence_id, int32_t status);
+
+/**
+ * The callback associated with the resume_geofence call.
+ *
+ * Parameter:
+ * geofence_id - Id of the geofence.
+ * status - GPS_GEOFENCE_OPERATION_SUCCESS
+ *          GPS_GEOFENCE_ERROR_ID_UNKNOWN - for invalid id
+ *          GPS_GEOFENCE_ERROR_GENERIC for others.
+ */
+typedef void (*gps_geofence_resume_callback) (int32_t geofence_id, int32_t status);
+
+typedef struct {
+    gps_geofence_transition_callback geofence_transition_callback;
+    gps_geofence_status_callback geofence_status_callback;
+    gps_geofence_add_callback geofence_add_callback;
+    gps_geofence_remove_callback geofence_remove_callback;
+    gps_geofence_pause_callback geofence_pause_callback;
+    gps_geofence_resume_callback geofence_resume_callback;
+    gps_create_thread create_thread_cb;
+} GpsGeofenceCallbacks;
+
+/** Extended interface for GPS_Geofencing support */
+typedef struct {
+   /** set to sizeof(GpsGeofencingInterface) */
+   size_t          size;
+
+   /**
+    * Opens the geofence interface and provides the callback routines
+    * to the implementation of this interface.
+    */
+   void  (*init)( GpsGeofenceCallbacks* callbacks );
+
+   /**
+    * Add a geofence area. This api currently supports circular geofences.
+    * Parameters:
+    *    geofence_id - The id for the geofence. If a geofence with this id
+    *       already exists, an error value (GPS_GEOFENCE_ERROR_ID_EXISTS)
+    *       should be returned.
+    *    latitude, longtitude, radius_meters - The lat, long and radius
+    *       (in meters) for the geofence
+    *    last_transition - The current state of the geofence. For example, if
+    *       the system already knows that the user is inside the geofence,
+    *       this will be set to GPS_GEOFENCE_ENTERED. In most cases, it
+    *       will be GPS_GEOFENCE_UNCERTAIN.
+    *    monitor_transition - Which transitions to monitor. Bitwise OR of
+    *       GPS_GEOFENCE_ENTERED, GPS_GEOFENCE_EXITED and
+    *       GPS_GEOFENCE_UNCERTAIN.
+    *    notification_responsiveness_ms - Defines the best-effort description
+    *       of how soon should the callback be called when the transition
+    *       associated with the Geofence is triggered. For instance, if set
+    *       to 1000 millseconds with GPS_GEOFENCE_ENTERED, the callback
+    *       should be called 1000 milliseconds within entering the geofence.
+    *       This parameter is defined in milliseconds.
+    *       NOTE: This is not to be confused with the rate that the GPS is
+    *       polled at. It is acceptable to dynamically vary the rate of
+    *       sampling the GPS for power-saving reasons; thus the rate of
+    *       sampling may be faster or slower than this.
+    *    unknown_timer_ms - The time limit after which the UNCERTAIN transition
+    *       should be triggered. This parameter is defined in milliseconds.
+    *       See above for a detailed explanation.
+    */
+   void (*add_geofence_area) (int32_t geofence_id, double latitude, double longitude,
+       double radius_meters, int last_transition, int monitor_transitions,
+       int notification_responsiveness_ms, int unknown_timer_ms);
+
+   /**
+    * Pause monitoring a particular geofence.
+    * Parameters:
+    *   geofence_id - The id for the geofence.
+    */
+   void (*pause_geofence) (int32_t geofence_id);
+
+   /**
+    * Resume monitoring a particular geofence.
+    * Parameters:
+    *   geofence_id - The id for the geofence.
+    *   monitor_transitions - Which transitions to monitor. Bitwise OR of
+    *       GPS_GEOFENCE_ENTERED, GPS_GEOFENCE_EXITED and
+    *       GPS_GEOFENCE_UNCERTAIN.
+    *       This supersedes the value associated provided in the
+    *       add_geofence_area call.
+    */
+   void (*resume_geofence) (int32_t geofence_id, int monitor_transitions);
+
+   /**
+    * Remove a geofence area. After the function returns, no notifications
+    * should be sent.
+    * Parameter:
+    *   geofence_id - The id for the geofence.
+    */
+   void (*remove_geofence_area) (int32_t geofence_id);
+} GpsGeofencingInterface;
+
+
+/**
+ * Represents an estimate of the GPS clock time.
+ */
+typedef struct {
+    /** set to sizeof(GpsClock) */
+    size_t size;
+
+    /** A set of flags indicating the validity of the fields in this data structure. */
+    GpsClockFlags flags;
+
+    /**
+     * Leap second data.
+     * The sign of the value is defined by the following equation:
+     *      utc_time_ns = time_ns + (full_bias_ns + bias_ns) - leap_second * 1,000,000,000
+     *
+     * If the data is available 'flags' must contain GPS_CLOCK_HAS_LEAP_SECOND.
+     */
+    int16_t leap_second;
+
+    /**
+     * Indicates the type of time reported by the 'time_ns' field.
+     * This is a Mandatory field.
+     */
+    GpsClockType type;
+
+    /**
+     * The GPS receiver internal clock value. This can be either the local hardware clock value
+     * (GPS_CLOCK_TYPE_LOCAL_HW_TIME), or the current GPS time derived inside GPS receiver
+     * (GPS_CLOCK_TYPE_GPS_TIME). The field 'type' defines the time reported.
+     *
+     * For local hardware clock, this value is expected to be monotonically increasing during
+     * the reporting session. The real GPS time can be derived by compensating the 'full bias'
+     * (when it is available) from this value.
+     *
+     * For GPS time, this value is expected to be the best estimation of current GPS time that GPS
+     * receiver can achieve. Set the 'time uncertainty' appropriately when GPS time is specified.
+     *
+     * Sub-nanosecond accuracy can be provided by means of the 'bias' field.
+     * The value contains the 'time uncertainty' in it.
+     *
+     * This is a Mandatory field.
+     */
+    int64_t time_ns;
+
+    /**
+     * 1-Sigma uncertainty associated with the clock's time in nanoseconds.
+     * The uncertainty is represented as an absolute (single sided) value.
+     *
+     * This value should be set if GPS_CLOCK_TYPE_GPS_TIME is set.
+     * If the data is available 'flags' must contain GPS_CLOCK_HAS_TIME_UNCERTAINTY.
+     */
+    double time_uncertainty_ns;
+
+    /**
+     * The difference between hardware clock ('time' field) inside GPS receiver and the true GPS
+     * time since 0000Z, January 6, 1980, in nanoseconds.
+     * This value is used if and only if GPS_CLOCK_TYPE_LOCAL_HW_TIME is set, and GPS receiver
+     * has solved the clock for GPS time.
+     * The caller is responsible for using the 'bias uncertainty' field for quality check.
+     *
+     * The sign of the value is defined by the following equation:
+     *      true time (GPS time) = time_ns + (full_bias_ns + bias_ns)
+     *
+     * This value contains the 'bias uncertainty' in it.
+     * If the data is available 'flags' must contain GPS_CLOCK_HAS_FULL_BIAS.
+     */
+    int64_t full_bias_ns;
+
+    /**
+     * Sub-nanosecond bias.
+     * The value contains the 'bias uncertainty' in it.
+     *
+     * If the data is available 'flags' must contain GPS_CLOCK_HAS_BIAS.
+     */
+    double bias_ns;
+
+    /**
+     * 1-Sigma uncertainty associated with the clock's bias in nanoseconds.
+     * The uncertainty is represented as an absolute (single sided) value.
+     *
+     * If the data is available 'flags' must contain GPS_CLOCK_HAS_BIAS_UNCERTAINTY.
+     */
+    double bias_uncertainty_ns;
+
+    /**
+     * The clock's drift in nanoseconds (per second).
+     * A positive value means that the frequency is higher than the nominal frequency.
+     *
+     * The value contains the 'drift uncertainty' in it.
+     * If the data is available 'flags' must contain GPS_CLOCK_HAS_DRIFT.
+     *
+     * If GpsMeasurement's 'flags' field contains GPS_MEASUREMENT_HAS_UNCORRECTED_PSEUDORANGE_RATE,
+     * it is encouraged that this field is also provided.
+     */
+    double drift_nsps;
+
+    /**
+     * 1-Sigma uncertainty associated with the clock's drift in nanoseconds (per second).
+     * The uncertainty is represented as an absolute (single sided) value.
+     *
+     * If the data is available 'flags' must contain GPS_CLOCK_HAS_DRIFT_UNCERTAINTY.
+     */
+    double drift_uncertainty_nsps;
+} GpsClock;
+
+/**
+ * Represents a GPS Measurement, it contains raw and computed information.
+ */
+typedef struct {
+    /** set to sizeof(GpsMeasurement) */
+    size_t size;
+
+    /** A set of flags indicating the validity of the fields in this data structure. */
+    GpsMeasurementFlags flags;
+
+    /**
+     * Pseudo-random number in the range of [1, 32]
+     * This is a Mandatory value.
+     */
+    int8_t prn;
+
+    /**
+     * Time offset at which the measurement was taken in nanoseconds.
+     * The reference receiver's time is specified by GpsData::clock::time_ns and should be
+     * interpreted in the same way as indicated by GpsClock::type.
+     *
+     * The sign of time_offset_ns is given by the following equation:
+     *      measurement time = GpsClock::time_ns + time_offset_ns
+     *
+     * It provides an individual time-stamp for the measurement, and allows sub-nanosecond accuracy.
+     * This is a Mandatory value.
+     */
+    double time_offset_ns;
+
+    /**
+     * Per satellite sync state. It represents the current sync state for the associated satellite.
+     * Based on the sync state, the 'received GPS tow' field should be interpreted accordingly.
+     *
+     * This is a Mandatory value.
+     */
+    GpsMeasurementState state;
+
+    /**
+     * Received GPS Time-of-Week at the measurement time, in nanoseconds.
+     * The value is relative to the beginning of the current GPS week.
+     *
+     * Given the highest sync state that can be achieved, per each satellite, valid range for
+     * this field can be:
+     *     Searching       : [ 0       ]   : GPS_MEASUREMENT_STATE_UNKNOWN
+     *     C/A code lock   : [ 0   1ms ]   : GPS_MEASUREMENT_STATE_CODE_LOCK is set
+     *     Bit sync        : [ 0  20ms ]   : GPS_MEASUREMENT_STATE_BIT_SYNC is set
+     *     Subframe sync   : [ 0    6s ]   : GPS_MEASUREMENT_STATE_SUBFRAME_SYNC is set
+     *     TOW decoded     : [ 0 1week ]   : GPS_MEASUREMENT_STATE_TOW_DECODED is set
+     *
+     * However, if there is any ambiguity in integer millisecond,
+     * GPS_MEASUREMENT_STATE_MSEC_AMBIGUOUS should be set accordingly, in the 'state' field.
+     *
+     * This value must be populated if 'state' != GPS_MEASUREMENT_STATE_UNKNOWN.
+     */
+    int64_t received_gps_tow_ns;
+
+    /**
+     * 1-Sigma uncertainty of the Received GPS Time-of-Week in nanoseconds.
+     *
+     * This value must be populated if 'state' != GPS_MEASUREMENT_STATE_UNKNOWN.
+     */
+    int64_t received_gps_tow_uncertainty_ns;
+
+    /**
+     * Carrier-to-noise density in dB-Hz, in the range [0, 63].
+     * It contains the measured C/N0 value for the signal at the antenna input.
+     *
+     * This is a Mandatory value.
+     */
+    double c_n0_dbhz;
+
+    /**
+     * Pseudorange rate at the timestamp in m/s.
+     * The correction of a given Pseudorange Rate value includes corrections for receiver and
+     * satellite clock frequency errors.
+     *
+     * If GPS_MEASUREMENT_HAS_UNCORRECTED_PSEUDORANGE_RATE is set in 'flags' field, this field must
+     * be populated with the 'uncorrected' reading.
+     * If GPS_MEASUREMENT_HAS_UNCORRECTED_PSEUDORANGE_RATE is not set in 'flags' field, this field
+     * must be populated with the 'corrected' reading. This is the default behavior.
+     *
+     * It is encouraged to provide the 'uncorrected' 'pseudorange rate', and provide GpsClock's
+     * 'drift' field as well.
+     *
+     * The value includes the 'pseudorange rate uncertainty' in it.
+     * A positive 'uncorrected' value indicates that the SV is moving away from the receiver.
+     *
+     * The sign of the 'uncorrected' 'pseudorange rate' and its relation to the sign of 'doppler
+     * shift' is given by the equation:
+     *      pseudorange rate = -k * doppler shift   (where k is a constant)
+     *
+     * This is a Mandatory value.
+     */
+    double pseudorange_rate_mps;
+
+    /**
+     * 1-Sigma uncertainty of the pseudurange rate in m/s.
+     * The uncertainty is represented as an absolute (single sided) value.
+     *
+     * This is a Mandatory value.
+     */
+    double pseudorange_rate_uncertainty_mps;
+
+    /**
+     * Accumulated delta range's state. It indicates whether ADR is reset or there is a cycle slip
+     * (indicating loss of lock).
+     *
+     * This is a Mandatory value.
+     */
+    GpsAccumulatedDeltaRangeState accumulated_delta_range_state;
+
+    /**
+     * Accumulated delta range since the last channel reset in meters.
+     * A positive value indicates that the SV is moving away from the receiver.
+     *
+     * The sign of the 'accumulated delta range' and its relation to the sign of 'carrier phase'
+     * is given by the equation:
+     *          accumulated delta range = -k * carrier phase    (where k is a constant)
+     *
+     * This value must be populated if 'accumulated delta range state' != GPS_ADR_STATE_UNKNOWN.
+     * However, it is expected that the data is only accurate when:
+     *      'accumulated delta range state' == GPS_ADR_STATE_VALID.
+     */
+    double accumulated_delta_range_m;
+
+    /**
+     * 1-Sigma uncertainty of the accumulated delta range in meters.
+     * This value must be populated if 'accumulated delta range state' != GPS_ADR_STATE_UNKNOWN.
+     */
+    double accumulated_delta_range_uncertainty_m;
+
+    /**
+     * Best derived Pseudorange by the chip-set, in meters.
+     * The value contains the 'pseudorange uncertainty' in it.
+     *
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_PSEUDORANGE.
+     */
+    double pseudorange_m;
+
+    /**
+     * 1-Sigma uncertainty of the pseudorange in meters.
+     * The value contains the 'pseudorange' and 'clock' uncertainty in it.
+     * The uncertainty is represented as an absolute (single sided) value.
+     *
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_PSEUDORANGE_UNCERTAINTY.
+     */
+    double pseudorange_uncertainty_m;
+
+    /**
+     * A fraction of the current C/A code cycle, in the range [0.0, 1023.0]
+     * This value contains the time (in Chip units) since the last C/A code cycle (GPS Msec epoch).
+     *
+     * The reference frequency is given by the field 'carrier_frequency_hz'.
+     * The value contains the 'code-phase uncertainty' in it.
+     *
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_CODE_PHASE.
+     */
+    double code_phase_chips;
+
+    /**
+     * 1-Sigma uncertainty of the code-phase, in a fraction of chips.
+     * The uncertainty is represented as an absolute (single sided) value.
+     *
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_CODE_PHASE_UNCERTAINTY.
+     */
+    double code_phase_uncertainty_chips;
+
+    /**
+     * Carrier frequency at which codes and messages are modulated, it can be L1 or L2.
+     * If the field is not set, the carrier frequency is assumed to be L1.
+     *
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_CARRIER_FREQUENCY.
+     */
+    float carrier_frequency_hz;
+
+    /**
+     * The number of full carrier cycles between the satellite and the receiver.
+     * The reference frequency is given by the field 'carrier_frequency_hz'.
+     *
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_CARRIER_CYCLES.
+     */
+    int64_t carrier_cycles;
+
+    /**
+     * The RF phase detected by the receiver, in the range [0.0, 1.0].
+     * This is usually the fractional part of the complete carrier phase measurement.
+     *
+     * The reference frequency is given by the field 'carrier_frequency_hz'.
+     * The value contains the 'carrier-phase uncertainty' in it.
+     *
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_CARRIER_PHASE.
+     */
+    double carrier_phase;
+
+    /**
+     * 1-Sigma uncertainty of the carrier-phase.
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_CARRIER_PHASE_UNCERTAINTY.
+     */
+    double carrier_phase_uncertainty;
+
+    /**
+     * An enumeration that indicates the 'loss of lock' state of the event.
+     */
+    GpsLossOfLock loss_of_lock;
+
+    /**
+     * The number of GPS bits transmitted since Sat-Sun midnight (GPS week).
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_BIT_NUMBER.
+     */
+    int32_t bit_number;
+
+    /**
+     * The elapsed time since the last received bit in milliseconds, in the range [0, 20]
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_TIME_FROM_LAST_BIT.
+     */
+    int16_t time_from_last_bit_ms;
+
+    /**
+     * Doppler shift in Hz.
+     * A positive value indicates that the SV is moving toward the receiver.
+     *
+     * The reference frequency is given by the field 'carrier_frequency_hz'.
+     * The value contains the 'doppler shift uncertainty' in it.
+     *
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_DOPPLER_SHIFT.
+     */
+    double doppler_shift_hz;
+
+    /**
+     * 1-Sigma uncertainty of the doppler shift in Hz.
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_DOPPLER_SHIFT_UNCERTAINTY.
+     */
+    double doppler_shift_uncertainty_hz;
+
+    /**
+     * An enumeration that indicates the 'multipath' state of the event.
+     */
+    GpsMultipathIndicator multipath_indicator;
+
+    /**
+     * Signal-to-noise ratio in dB.
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_SNR.
+     */
+    double snr_db;
+
+    /**
+     * Elevation in degrees, the valid range is [-90, 90].
+     * The value contains the 'elevation uncertainty' in it.
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_ELEVATION.
+     */
+    double elevation_deg;
+
+    /**
+     * 1-Sigma uncertainty of the elevation in degrees, the valid range is [0, 90].
+     * The uncertainty is represented as the absolute (single sided) value.
+     *
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_ELEVATION_UNCERTAINTY.
+     */
+    double elevation_uncertainty_deg;
+
+    /**
+     * Azimuth in degrees, in the range [0, 360).
+     * The value contains the 'azimuth uncertainty' in it.
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_AZIMUTH.
+     *  */
+    double azimuth_deg;
+
+    /**
+     * 1-Sigma uncertainty of the azimuth in degrees, the valid range is [0, 180].
+     * The uncertainty is represented as an absolute (single sided) value.
+     *
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_AZIMUTH_UNCERTAINTY.
+     */
+    double azimuth_uncertainty_deg;
+
+    /**
+     * Whether the GPS represented by the measurement was used for computing the most recent fix.
+     * If the data is available, 'flags' must contain GPS_MEASUREMENT_HAS_USED_IN_FIX.
+     */
+    bool used_in_fix;
+} GpsMeasurement;
+
+/** Represents a reading of GPS measurements. */
+typedef struct {
+    /** set to sizeof(GpsData) */
+    size_t size;
+
+    /** Number of measurements. */
+    size_t measurement_count;
+
+    /** The array of measurements. */
+    GpsMeasurement measurements[GPS_MAX_MEASUREMENT];
+
+    /** The GPS clock time reading. */
+    GpsClock clock;
+} GpsData;
+
+/**
+ * The callback for to report measurements from the HAL.
+ *
+ * Parameters:
+ *    data - A data structure containing the measurements.
+ */
+typedef void (*gps_measurement_callback) (GpsData* data);
+
+typedef struct {
+    /** set to sizeof(GpsMeasurementCallbacks) */
+    size_t size;
+    gps_measurement_callback measurement_callback;
+} GpsMeasurementCallbacks;
+
+#define GPS_MEASUREMENT_OPERATION_SUCCESS          0
+#define GPS_MEASUREMENT_ERROR_ALREADY_INIT      -100
+#define GPS_MEASUREMENT_ERROR_GENERIC           -101
+
+/**
+ * Extended interface for GPS Measurements support.
+ */
+typedef struct {
+    /** Set to sizeof(GpsMeasurementInterface) */
+    size_t size;
+
+    /**
+     * Initializes the interface and registers the callback routines with the HAL.
+     * After a successful call to 'init' the HAL must begin to provide updates at its own phase.
+     *
+     * Status:
+     *    GPS_MEASUREMENT_OPERATION_SUCCESS
+     *    GPS_MEASUREMENT_ERROR_ALREADY_INIT - if a callback has already been registered without a
+     *              corresponding call to 'close'
+     *    GPS_MEASUREMENT_ERROR_GENERIC - if any other error occurred, it is expected that the HAL
+     *              will not generate any updates upon returning this error code.
+     */
+    int (*init) (GpsMeasurementCallbacks* callbacks);
+
+    /**
+     * Stops updates from the HAL, and unregisters the callback routines.
+     * After a call to stop, the previously registered callbacks must be considered invalid by the
+     * HAL.
+     * If stop is invoked without a previous 'init', this function should perform no work.
+     */
+    void (*close) ();
+
+} GpsMeasurementInterface;
+
+
+/** Represents a GPS navigation message (or a fragment of it). */
+typedef struct {
+    /** set to sizeof(GpsNavigationMessage) */
+    size_t size;
+
+    /**
+     * Pseudo-random number in the range of [1, 32]
+     * This is a Mandatory value.
+     */
+    int8_t prn;
+
+    /**
+     * The type of message contained in the structure.
+     * This is a Mandatory value.
+     */
+    GpsNavigationMessageType type;
+
+    /**
+     * The status of the received navigation message.
+     * No need to send any navigation message that contains words with parity error and cannot be
+     * corrected.
+     */
+    NavigationMessageStatus status;
+
+    /**
+     * Message identifier.
+     * It provides an index so the complete Navigation Message can be assembled. i.e. fo L1 C/A
+     * subframe 4 and 5, this value corresponds to the 'frame id' of the navigation message.
+     * Subframe 1, 2, 3 does not contain a 'frame id' and this value can be set to -1.
+     */
+    int16_t message_id;
+
+    /**
+     * Sub-message identifier.
+     * If required by the message 'type', this value contains a sub-index within the current
+     * message (or frame) that is being transmitted.
+     * i.e. for L1 C/A the submessage id corresponds to the sub-frame id of the navigation message.
+     */
+    int16_t submessage_id;
+
+    /**
+     * The length of the data (in bytes) contained in the current message.
+     * If this value is different from zero, 'data' must point to an array of the same size.
+     * e.g. for L1 C/A the size of the sub-frame will be 40 bytes (10 words, 30 bits/word).
+     *
+     * This is a Mandatory value.
+     */
+    size_t data_length;
+
+    /**
+     * The data of the reported GPS message.
+     * The bytes (or words) specified using big endian format (MSB first).
+     *
+     * For L1 C/A, each subframe contains 10 30-bit GPS words. Each GPS word (30 bits) should be
+     * fitted into the last 30 bits in a 4-byte word (skip B31 and B32), with MSB first.
+     */
+    uint8_t* data;
+
+} GpsNavigationMessage;
+
+/**
+ * The callback to report an available fragment of a GPS navigation messages from the HAL.
+ *
+ * Parameters:
+ *      message - The GPS navigation submessage/subframe representation.
+ */
+typedef void (*gps_navigation_message_callback) (GpsNavigationMessage* message);
+
+typedef struct {
+    /** set to sizeof(GpsNavigationMessageCallbacks) */
+    size_t size;
+    gps_navigation_message_callback navigation_message_callback;
+} GpsNavigationMessageCallbacks;
+
+#define GPS_NAVIGATION_MESSAGE_OPERATION_SUCCESS             0
+#define GPS_NAVIGATION_MESSAGE_ERROR_ALREADY_INIT         -100
+#define GPS_NAVIGATION_MESSAGE_ERROR_GENERIC              -101
+
+/**
+ * Extended interface for GPS navigation message reporting support.
+ */
+typedef struct {
+    /** Set to sizeof(GpsNavigationMessageInterface) */
+    size_t size;
+
+    /**
+     * Initializes the interface and registers the callback routines with the HAL.
+     * After a successful call to 'init' the HAL must begin to provide updates as they become
+     * available.
+     *
+     * Status:
+     *      GPS_NAVIGATION_MESSAGE_OPERATION_SUCCESS
+     *      GPS_NAVIGATION_MESSAGE_ERROR_ALREADY_INIT - if a callback has already been registered
+     *              without a corresponding call to 'close'.
+     *      GPS_NAVIGATION_MESSAGE_ERROR_GENERIC - if any other error occurred, it is expected that
+     *              the HAL will not generate any updates upon returning this error code.
+     */
+    int (*init) (GpsNavigationMessageCallbacks* callbacks);
+
+    /**
+     * Stops updates from the HAL, and unregisters the callback routines.
+     * After a call to stop, the previously registered callbacks must be considered invalid by the
+     * HAL.
+     * If stop is invoked without a previous 'init', this function should perform no work.
+     */
+    void (*close) ();
+
+} GpsNavigationMessageInterface;
+
+/**
+ * Interface for passing GNSS configuration contents from platform to HAL.
+ */
+typedef struct {
+    /** Set to sizeof(GnssConfigurationInterface) */
+    size_t size;
+
+    /**
+     * Deliver GNSS configuration contents to HAL.
+     * Parameters:
+     *     config_data - a pointer to a char array which holds what usually is expected from
+                         file(/etc/gps.conf), i.e., a sequence of UTF8 strings separated by '\n'.
+     *     length - total number of UTF8 characters in configuraiton data.
+     *
+     * IMPORTANT:
+     *      GPS HAL should expect this function can be called multiple times. And it may be
+     *      called even when GpsLocationProvider is already constructed and enabled. GPS HAL
+     *      should maintain the existing requests for various callback regardless the change
+     *      in configuration data.
+     */
+    void (*configuration_update) (const char* config_data, int32_t length);
+} GnssConfigurationInterface;
+
+__END_DECLS
+
+#endif /* ANDROID_INCLUDE_HARDWARE_GPS_H */