MTK平台配置GNSS的不同模式

Android 5.1 相关源码：
hardware/mediatek/gps/mnl/mnl_aosp/mnld/src/mnld.c
hardware/mediatek/gps/mnl/mnl_aosp/inc/mtk_gps_type.h

Android 8.1 相关源码：
vendor/mediatek/proprietary/hardware/connectivity/gps/mtk_mnld/mnld_entity/src/gps_controller.c
vendor/mediatek/proprietary/hardware/connectivity/gps/mtk_mnld/mnl/inc/mtk_gps_type.h

不同GNSS模式的枚举定义：

// ******************   Important Notice *************************//
// In oder to make sure the GNSS configuration works correctly,
// Please delete "mtk_gps.dat" after change the MTK_GNSS_CONFIGURATION setting.
typedef enum
{MTK_CONFIG_GPS_GLONASS = 0,MTK_CONFIG_GPS_BEIDOU,MTK_CONFIG_GPS_GLONASS_BEIDOU,MTK_CONFIG_GPS_ONLY,MTK_CONFIG_BEIDOU_ONLY,MTK_CONFIG_GLONASS_ONLY,MTK_CONFIG_GPS_GLONASS_BEIDOU_GALILEO
} MTK_GNSS_CONFIGURATION;

源码配置使用的结构体，其中成员“GNSSOPMode”决定GNSS的模式：

static MNL_CONFIG_T mnl_config = {.init_speed = 38400,.link_speed = 921600,.debug_nmea = 1,.debug_mnl  = MNL_NEMA_DEBUG_SENTENCE,  /*MNL_NMEA_DEBUG_NORMAL,*/.pmtk_conn  = PMTK_CONNECTION_SOCKET,#ifdef GPS_SOCKET_ENABLE.socket_port = 7000,#else.socket_port = 0xFFFFF,#endif.dev_dbg = DBG_DEV,.dev_dsp = DSP_DEV,.dev_gps = "UseCallback",.bee_path = BEE_PATH,.epo_file = EPO_FILE,.epo_update_file = EPO_UPDATE_HAL,.qepo_file = QEPO_FILE,.qepo_update_file = QEPO_UPDATE_HAL,.delay_reset_dsp = 500,.nmea2file = 0,.dbg2file = 0,.nmea2socket = 1,.dbg2socket = 0,.timeout_init = 0,.timeout_monitor = 0,.timeout_wakeup = 0,.timeout_sleep = 0,.timeout_pwroff = 0,.timeout_ttff = 0,.EPO_enabled = 1,.BEE_enabled = 0,.SUPL_enabled = 1,.SUPLSI_enabled = 1,.EPO_priority = 64,.BEE_priority = 32,.SUPL_priority = 96,.fgGpsAosp_Ver = 1,.AVAILIABLE_AGE = 2,.RTC_DRIFT = 30,.TIME_INTERVAL = 10,.u1AgpsMachine = 0,  // default use spirent "0".ACCURACY_SNR = 1,/********************* 这里决定GNSS的模式 *************************/.GNSSOPMode = MTK_CONFIG_GPS_GLONASS_BEIDOU,/******************************************************************/.dbglog_file_max_size = 25*1024*1024,.dbglog_folder_max_size = 300*1024*1024
};

使用枚举“MTK_GNSS_CONFIGURATION”的值，修改上面结构体的成员“GNSSOPMode”的值，可以决定使用的GNSS模式！

此处修改之后，再搜索源码，看下有没有其他地方改动了“GNSSOPMode”的值，如果有改动，需要改成和上面结构体一样，如下：

 } else if (strcmp(chip_id, "0x8163") == 0) {mnl_config.GNSSOPMode = 3;  //如果用到的是这个主控，这里需要修改init_cfg.reservedy = (void *)MTK_GPS_CHIP_KEY_MT6735M;init_cfg.reservedx = MT6735M_E1;} else if (strcmp(chip_id, "0x6580") == 0) {