android 2.3 GPS 移植实战

刚刚开始接触 ANDROID GPS 的时候一头雾水，只好在网上找了很多关于GPS流程的说明。大致了解了GPS于哪几个文件有关

/framework/base/services/jni/com_android_server_location_GpsLocationProvider.cpp

hardware/libhardware_legacy/gps
hardware/libhardware_legacy/include/hardware_legacy/gps.h

通过查看文件，发现我的源码包里面 hardware/libhardware_legacy 目录里面没 GPS 文件夹。

咋整呢？

没办法，自己创建一个 

hardware/libhardware/modules/  下创建一个 GPS 文件夹， 在 hardware/libhardware_legacy/ 这下面也一样的，

记得修改 Android.mk 就可以了。

修改 hardware/libhardware/ 下的  Android.mk 文件

include $(addsuffix /Android.mk, $(addprefix $(LOCAL_PATH)/, \
modules/gralloc \
modules/gps \
tests \
))

把GPS文件夹包含的编译文件里面。

由于 android 模拟器有模拟 GPS 的源码，依葫芦画瓢呗。

把 gps_qemu.c 文件 COPY 到 刚刚创建的 GPS 文件夹内。

这样文件有了，就差一个 Android.mk 文件了。 

本人对这个文件并不熟悉，没办法，还是 COPY 把，把类似的 文件夹里面的 Android.mk 文件 COPY 过来做一些修改。

修改里面包含的文件啊，路径之类的。

我的 Android.mk 文件如下：

LOCAL_PATH := $(call my-dir)
# HAL module implemenation, not prelinked and stored in
# hw/<OVERLAY_HARDWARE_MODULE_ID>.<ro.product.board>.so
include $(CLEAR_VARS)
LOCAL_PRELINK_MODULE := false
LOCAL_MODULE_TAGS := eng
LOCAL_MODULE_PATH := $(TARGET_OUT_SHARED_LIBRARIES)/hw
LOCAL_SHARED_LIBRARIES := liblog libcutils
LOCAL_SRC_FILES :=  \
gps_qemu.c
LOCAL_MODULE := gps.default
#LOCAL_CFLAGS:= -DLOG_TAG=\"gps\"
ifeq ($(BOARD_NO_PAGE_FLIPPING),true)
LOCAL_CFLAGS += -DNO_PAGE_FLIPPING
endif
include $(BUILD_SHARED_LIBRARY)

下一步就是 gps_qemu.c 的修改了

首先是 gps_state_init 打开串口设备

state->fd = open(GPS_Serial_Name, O_RDONLY );

这里打开串口，GPS_Serial_Name 这根据自己的设备查找对应串口的设备节点。

设置串口事件

// disable echo on serial lines
    if ( isatty( state->fd ) ) {
        struct termios  ios;
        tcgetattr( state->fd, &ios );
        ios.c_lflag = 0;  /* disable ECHO, ICANON, etc... */
        ios.c_oflag &= (~ONLCR); /* Stop \n -> \r\n translation on output */
        ios.c_iflag &= (~(ICRNL | INLCR)); /* Stop \r -> \n & \n -> \r translation on input */
        ios.c_iflag |= (IGNCR | IXOFF);  /* Ignore \r & XON/XOFF on input */
cfsetispeed(&ios, B38400);
    cfsetospeed(&ios, B38400);
        tcsetattr( state->fd, TCSANOW, &ios );
    }

这一步非常重要，如果没有这一步，那么在 GPS HAL 线程里面不会接收串口数据。

这样 Android 的 HAL 层于串口就接通了。

接下来就是解析串口数据，由于模拟器里面已经有解析 RMC 的GPS结构。

所以直接测试就可以了。

直接测试后发现当有 GPS 数据调用 CALLBACK 函数

 if (r->callback) 
{
            r->callback( &r->fix );
            r->fix.flags = 0;

}

后 ANDROID 重启了，查询网上资料，发现很多同志在 2.3 也碰到这问题，主要是创建线程的问题。

把创建线程的函数换一下就好了。

/*
    if ( pthread_create( &state->thread, NULL, gps_state_thread, state ) != 0 ) {
        LOGE("could not create gps thread: %s", strerror(errno));
        goto Fail;
    }
*/
    state->thread = state->callbacks.create_thread_cb("qemu_gps",  gps_state_thread, state);

这样系统就能正常启动并接收经纬度了。

接收经纬度后 关闭 GPS 再打开，发现 GPS 没有经纬度了，奇怪

通过跟踪，发现在 GPS 关闭后会调用 HAL 层  qemu_gps_cleanup 把串口关闭，

当重新开启的时候 调用 JNI 

/framework/base/services/jni/com_android_server_location_GpsLocationProvider.cpp

里面的 android_location_GpsLocationProvider_init，发现里面的 sGpsInterface 指针已经存在，

就不会调用 sGpsInterface->init 函数。

所以在 JNI 层的 cleanup 函数里面把这个指针清除。

static void android_location_GpsLocationProvider_cleanup(JNIEnv* env, jobject obj)
{
    const GpsInterface* interface = GetGpsInterface(env, obj);
    LOGE("%s \n", __FUNCTION__);
    if (interface)
        interface->cleanup();
    sGpsInterface = NULL ;
}

这样就可以啦， GPS 移植已经 OK 现在还有一个 BUG 就是状态栏那个 GPS 图标，

关闭 GPS 后不知道为什么不会消失，还需要进一步研究。

下面是我的 gps_qemu.c 文件。

/*
 * 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.
 */

/* this implements a GPS hardware library for the Android emulator.
 * the following code should be built as a shared library that will be
 * placed into /system/lib/hw/gps.goldfish.so
 *
 * it will be loaded by the code in hardware/libhardware/hardware.c
 * which is itself called from android_location_GpsLocationProvider.cpp
 */
#include <errno.h>
#include <pthread.h>
#include <termios.h>
#include <fcntl.h>
#include <sys/epoll.h>
#include <math.h>
#include <time.h>
#include <semaphore.h>
#include <signal.h>
#include <unistd.h>

#define  LOG_TAG  "gps_qemu"
#include <cutils/log.h>
#include <cutils/sockets.h>
#include <cutils/properties.h>
//#include <hardware_legacy/gps.h>
#include <hardware/gps.h>
//frank

/* the name of the qemud-controlled socket */
#define  QEMU_CHANNEL_NAME  "gps"
#define  GPS_DEBUG  1
#define GPS_TestData "$GPRMC,053322.682,A,2502.6538,N,12121.4838,E,0.00,080905,,,A*6F\n"
#define GPS_Serial_Name "/dev/s3c2410_serial3"
#if GPS_DEBUG
#  define  D(...)   LOGD(__VA_ARGS__)
#else
#  define  D(...)   ((void)0)
#endif

/*****************************************************************/
/*****************************************************************/
/*****                                                       *****/
/*****       N M E A   T O K E N I Z E R                     *****/
/*****                                                       *****/
/*****************************************************************/
/*****************************************************************/
static const void * qemu_gps_get_extension(const char* name);

/* this is the state of our connection to the qemu_gpsd daemon */
typedef struct {
    int                     init;
    int                     fd;
    GpsCallbacks            callbacks;
    pthread_t               thread;
    sem_t                   fix_sem;
    int                     control[2];
} GpsState;
static GpsState  _gps_state[1];
static GpsState *gps_state = _gps_state;

/* Since NMEA parser requires lcoks */
#define GPS_STATE_LOCK_FIX(_s)         \
{                                      \
  int ret;                             \
  do {                                 \
    ret = sem_wait(&(_s)->fix_sem);    \
  } while (ret < 0 && errno == EINTR);   \
} 
  
#define GPS_STATE_UNLOCK_FIX(_s)       \
  sem_post(&(_s)->fix_sem)
  
typedef struct {
    const char*  p;
    const char*  end;
} Token;

#define  MAX_NMEA_TOKENS  16

typedef struct {
    int     count;
    Token   tokens[ MAX_NMEA_TOKENS ];
} NmeaTokenizer;

static int
nmea_tokenizer_init( NmeaTokenizer*  t, const char*  p, const char*  end )
{
    int    count = 0;
    char*  q;

    // the initial '$' is optional
    if (p < end && p[0] == '$')
        p += 1;

    // remove trailing newline
    if (end > p && end[-1] == '\n') {
        end -= 1;
        if (end > p && end[-1] == '\r')
            end -= 1;
    }

    // get rid of checksum at the end of the sentecne
    if (end >= p+3 && end[-3] == '*') {
        end -= 3;
    }

    while (p < end) {
        const char*  q = p;
        q = memchr(p, ',', end-p);
        if (q == NULL)
            q = end;
        if (q > p) {
            if (count < MAX_NMEA_TOKENS) {
                t->tokens[count].p   = p;
                t->tokens[count].end = q;
                count += 1;
            }
        }
        if (q < end)
            q += 1;
        p = q;
    }

    t->count = count;
    return count;
}

static Token
nmea_tokenizer_get( NmeaTokenizer*  t, int  index )
{
    Token  tok;
    static const char*  dummy = "";
    if (index < 0 || index >= t->count) {
        tok.p = tok.end = dummy;
    } else
        tok = t->tokens[index];

    return tok;
}

static int
str2int( const char*  p, const char*  end )
{
    int   result = 0;
    int   len    = end - p;
    for ( ; len > 0; len--, p++ )
    {
        int  c;
        if (p >= end)
            goto Fail;

        c = *p - '0';
        if ((unsigned)c >= 10)
            goto Fail;

        result = result*10 + c;
    }
    return  result;

Fail:
    return -1;
}

static double
str2float( const char*  p, const char*  end )
{
    int   result = 0;
    int   len    = end - p;
    char  temp[16];
    if (len >= (int)sizeof(temp))
        return 0.;
    memcpy( temp, p, len );
    temp[len] = 0;
    return strtod( temp, NULL );
}

/*****************************************************************/
/*****************************************************************/
/*****                                                       *****/
/*****       N M E A   P A R S E R                           *****/
/*****                                                       *****/
/*****************************************************************/
/*****************************************************************/

#define  NMEA_MAX_SIZE  83

typedef struct {
    int     pos;
    int     overflow;
    int     utc_year;
    int     utc_mon;
    int     utc_day;
    int     utc_diff;
    GpsLocation  fix;
    GpsSvStatus  sv_status;
    gps_location_callback  callback;
    int     sv_status_changed;
    char    in[ NMEA_MAX_SIZE+1 ];
} NmeaReader;

static void
nmea_reader_update_utc_diff( NmeaReader*  r )
{
    time_t         now = time(NULL);
    struct tm      tm_local;
    struct tm      tm_utc;
    long           time_local, time_utc;

    gmtime_r( &now, &tm_utc );
    localtime_r( &now, &tm_local );

    time_local = tm_local.tm_sec +
                 60*(tm_local.tm_min +
                 60*(tm_local.tm_hour +
                 24*(tm_local.tm_yday +
                 365*tm_local.tm_year)));
    time_utc = tm_utc.tm_sec +
               60*(tm_utc.tm_min +
               60*(tm_utc.tm_hour +
               24*(tm_utc.tm_yday +
               365*tm_utc.tm_year)));
    r->utc_diff = time_utc - time_local;
}

static void
nmea_reader_init( NmeaReader*  r )
{
    memset( r, 0, sizeof(*r) );

    r->pos      = 0;
    r->overflow = 0;
    r->utc_year = -1;
    r->utc_mon  = -1;
    r->utc_day  = -1;
    r->callback = NULL;
    r->fix.size = sizeof(r->fix);
    nmea_reader_update_utc_diff( r );
}

static void
nmea_reader_set_callback( NmeaReader*  r, gps_location_callback  cb )
{
    r->callback = cb;
//r->fix.flags=0x0008;//data for test callback
   // D("%s: callback=%x flags=%d \n", __FUNCTION__,cb,r->fix.flags);
    if (cb != NULL && r->fix.flags != 0) {
        D("%s: sending latest fix to new callback", __FUNCTION__);
        r->callback( &r->fix );
        r->fix.flags = 0;
    }
}

static int
nmea_reader_update_time( NmeaReader*  r, Token  tok )
{
    int        hour, minute;
    double     seconds;
    struct tm  tm;
    time_t     fix_time;
    if (tok.p + 6 > tok.end)
        return -1;

    if (r->utc_year < 0) {
        // no date yet, get current one
        time_t  now = time(NULL);
        gmtime_r( &now, &tm );
        r->utc_year = tm.tm_year + 1900;
        r->utc_mon  = tm.tm_mon + 1;
        r->utc_day  = tm.tm_mday;
    }

    hour    = str2int(tok.p,   tok.p+2);
    minute  = str2int(tok.p+2, tok.p+4);
    seconds = str2float(tok.p+4, tok.end);
    tm.tm_hour  = hour;
    tm.tm_min   = minute;
    tm.tm_sec   = (int) seconds;
    tm.tm_year  = r->utc_year - 1900;
    tm.tm_mon   = r->utc_mon - 1;
    tm.tm_mday  = r->utc_day;
    tm.tm_isdst = -1;

    fix_time = mktime( &tm ) + r->utc_diff;
    r->fix.timestamp = (long long)fix_time * 1000;
    return 0;
}

static int
nmea_reader_update_date( NmeaReader*  r, Token  date, Token  time )
{
    Token  tok = date;
    int    day, mon, year;

    if (tok.p + 6 != tok.end) {
        D("date not properly formatted: '%.*s'", tok.end-tok.p, tok.p);
        return -1;
    }
    day  = str2int(tok.p, tok.p+2);
    mon  = str2int(tok.p+2, tok.p+4);
    year = str2int(tok.p+4, tok.p+6) + 2000;

    if ((day|mon|year) < 0) {
        D("date not properly formatted: '%.*s'", tok.end-tok.p, tok.p);
        return -1;
    }

    r->utc_year  = year;
    r->utc_mon   = mon;
    r->utc_day   = day;

    return nmea_reader_update_time( r, time );
}

static double
convert_from_hhmm( Token  tok )
{
    double  val     = str2float(tok.p, tok.end);
    int     degrees = (int)(floor(val) / 100);
    double  minutes = val - degrees*100.;
    double  dcoord  = degrees + minutes / 60.0;
    return dcoord;
}

static int
nmea_reader_update_latlong( NmeaReader*  r,
                            Token        latitude,
                            char         latitudeHemi,
                            Token        longitude,
                            char         longitudeHemi )
{
    double   lat, lon;
    Token    tok;

    D("%s \n", __FUNCTION__);
    tok = latitude;
    if (tok.p + 6 > tok.end) {
        D("latitude is too short: '%.*s'", tok.end-tok.p, tok.p);
        return -1;
    }
    lat = convert_from_hhmm(tok);
    if (latitudeHemi == 'S')
        lat = -lat;
    tok = longitude;
    if (tok.p + 6 > tok.end) {
        D("longitude is too short: '%.*s'", tok.end-tok.p, tok.p);
        return -1;
    }
    lon = convert_from_hhmm(tok);
    if (longitudeHemi == 'W')
        lon = -lon;
    //D("GPS_LOCATION_HAS_LAT_LONG \n");
    r->fix.flags    |= GPS_LOCATION_HAS_LAT_LONG;
    r->fix.latitude  = lat;
    r->fix.longitude = lon;
    return 0;
}

static int
nmea_reader_update_altitude( NmeaReader*  r,
                             Token        altitude,
                             Token        units )
{
    double  alt;
    Token   tok = altitude;
    D("%s \n", __FUNCTION__);
    if (tok.p >= tok.end)
        return -1;
//D("longitude is too short GPS_LOCATION_HAS_ALTITUDE \n");
    r->fix.flags   |= GPS_LOCATION_HAS_ALTITUDE;
    r->fix.altitude = str2float(tok.p, tok.end);
    return 0;
}

static int
nmea_reader_update_bearing( NmeaReader*  r,
                            Token        bearing )
{
    double  alt;
    Token   tok = bearing;

   // D("%s \n", __FUNCTION__);
    if (tok.p >= tok.end)
        return -1;
//D("GPS_LOCATION_HAS_BEARING \n");
    r->fix.flags   |= GPS_LOCATION_HAS_BEARING;
    r->fix.bearing  = str2float(tok.p, tok.end);
    return 0;
}

static int
nmea_reader_update_cdate( NmeaReader*  r, Token  tok_d, Token tok_m, Token tok_y )
{
    if ( (tok_d.p + 2 > tok_d.end) ||
         (tok_m.p + 2 > tok_m.end) ||
         (tok_y.p + 4 > tok_y.end) )
        return -1;
 
    r->utc_day = str2int(tok_d.p,   tok_d.p+2);
    r->utc_mon = str2int(tok_m.p, tok_m.p+2);
    r->utc_year = str2int(tok_y.p, tok_y.end+4);
 
    return 0;
}

static int
nmea_reader_update_speed( NmeaReader*  r,
                          Token        speed )
{
    double  alt;
    Token   tok = speed;
    //D("%s \n", __FUNCTION__);
    if (tok.p >= tok.end)
        return -1;
//D("GPS_LOCATION_HAS_SPEED \n");
    r->fix.flags   |= GPS_LOCATION_HAS_SPEED;
    r->fix.speed    = str2float(tok.p, tok.end);
    return 0;
}
static int
nmea_reader_update_accuracy( NmeaReader*  r,
                             Token        accuracy )
{
    double  acc;
    Token   tok = accuracy;
 
    if (tok.p >= tok.end)
        return -1;
    r->fix.accuracy = str2float(tok.p, tok.end);
    if (r->fix.accuracy == 99.99){
      return 0;
    }
 //frank
//LOGD("nmea_reader_update_accuracy");
    r->fix.flags   |= GPS_LOCATION_HAS_ACCURACY;
    return 0;
}
 
static void
nmea_reader_parse( NmeaReader*  r )
{
   /* we received a complete sentence, now parse it to generate
    * a new GPS fix...
    */
    NmeaTokenizer  tzer[1];
    Token          tok;
    D("Received: '%.*s'", r->pos, r->in);
    if (r->pos < 9) {
        D("Too short. discarded.");
        return;
    }
    nmea_tokenizer_init(tzer, r->in, r->in + r->pos);
//#if GPS_DEBUG
#if 0
    {
        int  n;
        D("Found %d tokens", tzer->count);
        for (n = 0; n < tzer->count; n++) {
            Token  tok = nmea_tokenizer_get(tzer,n);
            D("%2d: '%.*s'", n, tok.end-tok.p, tok.p);
        }
    }
#endif
    tok = nmea_tokenizer_get(tzer, 0);
    if (tok.p + 5 > tok.end) {
        D("sentence id '%.*s' too short, ignored.", tok.end-tok.p, tok.p);
        return;
    }
    // ignore first two characters.
    tok.p += 2;
    if ( !memcmp(tok.p, "GGA", 3) ) {
        // GPS fix
        Token  tok_time          = nmea_tokenizer_get(tzer,1);
        Token  tok_latitude      = nmea_tokenizer_get(tzer,2);
        Token  tok_latitudeHemi  = nmea_tokenizer_get(tzer,3);
        Token  tok_longitude     = nmea_tokenizer_get(tzer,4);
        Token  tok_longitudeHemi = nmea_tokenizer_get(tzer,5);
        Token  tok_altitude      = nmea_tokenizer_get(tzer,9);
        Token  tok_altitudeUnits = nmea_tokenizer_get(tzer,10);
        nmea_reader_update_time(r, tok_time);
        nmea_reader_update_latlong(r, tok_latitude,
                                      tok_latitudeHemi.p[0],
                                      tok_longitude,
                                      tok_longitudeHemi.p[0]);
        nmea_reader_update_altitude(r, tok_altitude, tok_altitudeUnits);
    } else if ( !memcmp(tok.p, "GLL", 3) ) {
LOGD(">>>>>>>> GLL string");
 
        Token  tok_fixstaus      = nmea_tokenizer_get(tzer,6);
        if (tok_fixstaus.p[0] == 'A') {
 
          Token  tok_latitude      = nmea_tokenizer_get(tzer,1);
          Token  tok_latitudeHemi  = nmea_tokenizer_get(tzer,2);
          Token  tok_longitude     = nmea_tokenizer_get(tzer,3);
          Token  tok_longitudeHemi = nmea_tokenizer_get(tzer,4);
          Token  tok_time          = nmea_tokenizer_get(tzer,5);
 
          nmea_reader_update_time(r, tok_time);
          nmea_reader_update_latlong(r, tok_latitude,
                                        tok_latitudeHemi.p[0],
                                        tok_longitude,
                                        tok_longitudeHemi.p[0]);
        }
 
    }else if ( !memcmp(tok.p, "GSA", 3) ) {
        // do something ?
LOGD(">>>>>>>> GSA string");
        Token  tok_fixStatus   = nmea_tokenizer_get(tzer, 2);
        int i;
 
        if (tok_fixStatus.p[0] != '\0' && tok_fixStatus.p[0] != '1') {
          Token  tok_accuracy      = nmea_tokenizer_get(tzer, 15);
          nmea_reader_update_accuracy(r, tok_accuracy);
          r->sv_status.used_in_fix_mask = 0ul;
          for (i = 3; i <= 14; ++i){
            Token  tok_prn  = nmea_tokenizer_get(tzer, i);
            int prn = str2int(tok_prn.p, tok_prn.end);
            if (prn > 0){
              r->sv_status.used_in_fix_mask |= (1ul << (32 - prn));
              r->sv_status_changed = 1;
            //  D("%s: fix mask is %d", __FUNCTION__, r->sv_status.used_in_fix_mask);
            }
          }
        }
    } else if ( !memcmp(tok.p, "GSV", 3) ) {
        Token  tok_noSatellites  = nmea_tokenizer_get(tzer, 3);
        int    noSatellites = str2int(tok_noSatellites.p, tok_noSatellites.end);
      
        if (noSatellites > 0) {
          Token  tok_noSentences   = nmea_tokenizer_get(tzer, 1);
          Token  tok_sentence      = nmea_tokenizer_get(tzer, 2);
          int sentence = str2int(tok_sentence.p, tok_sentence.end);
          int totalSentences = str2int(tok_noSentences.p, tok_noSentences.end);
          int curr;
          int i;
          if (sentence == 1) {
              r->sv_status_changed = 0;
              r->sv_status.num_svs = 0;
          }
          curr = r->sv_status.num_svs;
          i = 0;
          while (i < 4 && r->sv_status.num_svs < noSatellites){
                 Token  tok_prn = nmea_tokenizer_get(tzer, i * 4 + 4);
                 Token  tok_elevation = nmea_tokenizer_get(tzer, i * 4 + 5);
                 Token  tok_azimuth = nmea_tokenizer_get(tzer, i * 4 + 6);
                 Token  tok_snr = nmea_tokenizer_get(tzer, i * 4 + 7);
 
                 r->sv_status.sv_list[curr].prn = str2int(tok_prn.p, tok_prn.end);
                 r->sv_status.sv_list[curr].elevation = str2float(tok_elevation.p, tok_elevation.end);
                 r->sv_status.sv_list[curr].azimuth = str2float(tok_azimuth.p, tok_azimuth.end);
                 r->sv_status.sv_list[curr].snr = str2float(tok_snr.p, tok_snr.end);
 
                 r->sv_status.num_svs += 1;
                 curr += 1;
                 i += 1;
          }
 
          if (sentence == totalSentences) {
              r->sv_status_changed = 1;
          }
         // LOGD("%s: GSV message with total satellites %d", __FUNCTION__, noSatellites);   
        }
    } else if ( !memcmp(tok.p, "RMC", 3) ) {
        Token  tok_time          = nmea_tokenizer_get(tzer,1);
        Token  tok_fixStatus     = nmea_tokenizer_get(tzer,2);
        Token  tok_latitude      = nmea_tokenizer_get(tzer,3);
        Token  tok_latitudeHemi  = nmea_tokenizer_get(tzer,4);
        Token  tok_longitude     = nmea_tokenizer_get(tzer,5);
        Token  tok_longitudeHemi = nmea_tokenizer_get(tzer,6);
        Token  tok_speed         = nmea_tokenizer_get(tzer,7);
        Token  tok_bearing       = nmea_tokenizer_get(tzer,8);
        Token  tok_date          = nmea_tokenizer_get(tzer,9);

        D("in RMC, fixStatus=%c", tok_fixStatus.p[0]);
        if (tok_fixStatus.p[0] == 'A')
        {
            nmea_reader_update_date( r, tok_date, tok_time );
            nmea_reader_update_latlong( r, tok_latitude,
                                           tok_latitudeHemi.p[0],
                                           tok_longitude,
                                           tok_longitudeHemi.p[0] );
            nmea_reader_update_bearing( r, tok_bearing );
            nmea_reader_update_speed  ( r, tok_speed );
        }
    } else if ( !memcmp(tok.p, "VTG", 3) ) {
        Token  tok_fixStatus     = nmea_tokenizer_get(tzer,9);
        if (tok_fixStatus.p[0] != '\0' && tok_fixStatus.p[0] != 'N')
        {
            Token  tok_bearing       = nmea_tokenizer_get(tzer,1);
            Token  tok_speed         = nmea_tokenizer_get(tzer,5);
 
            nmea_reader_update_bearing( r, tok_bearing );
            nmea_reader_update_speed  ( r, tok_speed );
        }
    } else if ( !memcmp(tok.p, "ZDA", 3) ) {
        Token  tok_time;
        Token  tok_year  = nmea_tokenizer_get(tzer,4);
        if (tok_year.p[0] != '\0') {
          Token  tok_day   = nmea_tokenizer_get(tzer,2);
          Token  tok_mon   = nmea_tokenizer_get(tzer,3);
          nmea_reader_update_cdate( r, tok_day, tok_mon, tok_year );
        }

        tok_time  = nmea_tokenizer_get(tzer,1);
        if (tok_time.p[0] != '\0') {
          nmea_reader_update_time(r, tok_time);
        }
    }else {
        tok.p -= 2;
        D("unknown sentence '%.*s", tok.end-tok.p, tok.p);
    }
    if (r->fix.flags != 0) {
#if GPS_DEBUG
        char   temp[256];
        char*  p   = temp;
        char*  end = p + sizeof(temp);
        struct tm   utc;
        p += snprintf( p, end-p, "sending fix" );
        if (r->fix.flags & GPS_LOCATION_HAS_LAT_LONG) {
            p += snprintf(p, end-p, " lat=%g lon=%g", r->fix.latitude, r->fix.longitude);
        }
        if (r->fix.flags & GPS_LOCATION_HAS_ALTITUDE) {
            p += snprintf(p, end-p, " altitude=%g", r->fix.altitude);
        }
        if (r->fix.flags & GPS_LOCATION_HAS_SPEED) {
            p += snprintf(p, end-p, " speed=%g", r->fix.speed);
        }
        if (r->fix.flags & GPS_LOCATION_HAS_BEARING) {
            p += snprintf(p, end-p, " bearing=%g", r->fix.bearing);
        }
        if (r->fix.flags & GPS_LOCATION_HAS_ACCURACY) {
            p += snprintf(p,end-p, " accuracy=%g", r->fix.accuracy);
        }
        gmtime_r( (time_t*) &r->fix.timestamp, &utc );
        p += snprintf(p, end-p, " time=%s", asctime( &utc ) );
        D("%s",temp);
#endif
        if (r->callback) 
{
            r->callback( &r->fix );
            r->fix.flags = 0;
    if (r->sv_status_changed != 0) 
    {
LOGD("gps sv status callback");
if (gps_state->callbacks.sv_status_cb) 
{
    //frank
    LOGD("gps sv status callback---2");
    gps_state->callbacks.sv_status_cb( &r->sv_status );
    r->sv_status_changed = 0;
}
    }
        }
        else {
            D("no callback, keeping data until needed !");
        }
    }
}


static void
nmea_reader_addc( NmeaReader*  r, int  c )
{
    if (r->overflow) {
        r->overflow = (c != '\n');
        return;
    }
    if (r->pos >= (int) sizeof(r->in)-1 ) {
        r->overflow = 1;
        r->pos      = 0;
        return;
    }
    r->in[r->pos] = (char)c;
    r->pos       += 1;
    if (c == '\n') {
GPS_STATE_LOCK_FIX(gps_state);//--frank--2011-10-13
        nmea_reader_parse( r );
GPS_STATE_UNLOCK_FIX(gps_state);//--frank--2011-10-13
        r->pos = 0;
    }
}

/*****************************************************************/
/*****************************************************************/
/*****                                                       *****/
/*****       C O N N E C T I O N   S T A T E                 *****/
/*****                                                       *****/
/*****************************************************************/
/*****************************************************************/
/* commands sent to the gps thread */
enum {
    CMD_QUIT  = 0,
    CMD_START = 1,
    CMD_STOP  = 2
};

static void
gps_state_done( GpsState*  s )
{
    // tell the thread to quit, and wait for it
    char   cmd = CMD_QUIT;
    int ret;
    void*  dummy;
    D("gps send quit command");
    do{
        ret = write( s->control[0], &cmd, 1 );
    }while(ret<0 && errno == EINTR);
    pthread_join(s->thread, &dummy);
    // close the control socket pair
    close( s->control[0] ); s->control[0] = -1;
    close( s->control[1] ); s->control[1] = -1;
    // close connection to the QEMU GPS daemon
    close( s->fd ); s->fd = -1;
    sem_destroy(&s->fix_sem);
    s->init = 0;
    D("gps send quit end");
}

static void
gps_state_start( GpsState*  s )
{
    char  cmd = CMD_START;
    int   ret;
    do { ret=write( s->control[0], &cmd, 1 ); }
    while (ret < 0 && errno == EINTR);
    if (ret != 1)
        D("%s: could not send CMD_START command: ret=%d: %s",
          __FUNCTION__, ret, strerror(errno));
}

static void
gps_state_stop( GpsState*  s )
{
    char  cmd = CMD_STOP;
    int   ret;
    do { ret=write( s->control[0], &cmd, 1 ); }
    while (ret < 0 && errno == EINTR);
    if (ret != 1)
        D("%s: could not send CMD_STOP command: ret=%d: %s",
          __FUNCTION__, ret, strerror(errno));
}

static int
epoll_register( int  epoll_fd, int  fd )
{
    struct epoll_event  ev;
    int                 ret, flags;
    /* important: make the fd non-blocking */
    flags = fcntl(fd, F_GETFL);
    fcntl(fd, F_SETFL, flags | O_NONBLOCK);
    ev.events  = EPOLLIN;
    ev.data.fd = fd;
    do {
        ret = epoll_ctl( epoll_fd, EPOLL_CTL_ADD, fd, &ev );
    } while (ret < 0 && errno == EINTR);
    return ret;
}

static int
epoll_deregister( int  epoll_fd, int  fd )
{
    int  ret;
    do {
        ret = epoll_ctl( epoll_fd, EPOLL_CTL_DEL, fd, NULL );
    } while (ret < 0 && errno == EINTR);
    return ret;
}

/* this is the main thread, it waits for commands from gps_state_start/stop and,
 * when started, messages from the QEMU GPS daemon. these are simple NMEA sentences
 * that must be parsed to be converted into GPS fixes sent to the framework
 */
static void*
gps_state_thread( void*  arg )
{
    GpsState*   state = (GpsState*) arg;
    NmeaReader  reader[1];
    int         epoll_fd   = epoll_create(2);
    int         started    = 0;
    int         gps_fd     = state->fd;
    int         control_fd = state->control[1];
    nmea_reader_init( reader );
    // register control file descriptors for polling
    epoll_register( epoll_fd, control_fd );
    epoll_register( epoll_fd, gps_fd );
    D("gps thread running");
    // now loop
    for (;;) {
        struct epoll_event   events[2];
        int                  ne, nevents;
        nevents = epoll_wait( epoll_fd, events, 2, -1 );
        if (nevents < 0) {
            if (errno != EINTR)
                LOGE("epoll_wait() unexpected error: %s", strerror(errno));
            continue;
        }
        //D("gps thread received %d events", nevents);
        for (ne = 0; ne < nevents; ne++) {
            if ((events[ne].events & (EPOLLERR|EPOLLHUP)) != 0) {
                LOGE("EPOLLERR or EPOLLHUP after epoll_wait() !?");
                goto Exit;
            }
            if ((events[ne].events & EPOLLIN) != 0) {
                int  fd = events[ne].data.fd;
                if (fd == control_fd)
                {
                    char  cmd = 255;
                    int   ret;
                    D("gps control fd event");
                    do {
                        ret = read( fd, &cmd, 1 );
                    } while (ret < 0 && errno == EINTR);

                    if (cmd == CMD_QUIT) {
                        D("gps thread quitting on demand");
                        goto Exit;
                    }
                    else if (cmd == CMD_START) {
                        if (!started) {
                            D("gps thread starting  location_cb=%p", state->callbacks.location_cb);
                            started = 1;
                            nmea_reader_set_callback( reader, state->callbacks.location_cb );
    if(state->callbacks.location_cb != NULL)
    {
state->callbacks.location_cb(NULL);
    }
/*    char testbuf[100];
    int nn;
    sprintf(testbuf,"%s",GPS_TestData);
    for (nn = 0; nn < strlen(testbuf); nn++)
{
   // D("%02x ",buff[nn]);
                    nmea_reader_addc( reader, testbuf[nn] );
}*/
                        }
                    }
                    else if (cmd == CMD_STOP) {
                        if (started) {
                            D("gps thread stopping");
                            started = 0;
                            nmea_reader_set_callback( reader, NULL );
                        }
                    }
                }
                else if (fd == gps_fd)
                {
                    char  buff[32];
                 //   D("gps fd event\n");
                    for (;;) {
                        int  nn, ret;
                        ret = read( fd, buff, sizeof(buff) );
                        if (ret < 0) {
                            if (errno == EINTR)
                                continue;
                            if (errno != EWOULDBLOCK)
                                LOGE("error while reading from gps daemon socket: %s:", strerror(errno));
                            break;
                        }
                        //D("received %d bytes: %.*s", ret, ret, buff);
                        for (nn = 0; nn < ret; nn++)
{
   // D("%02x ",buff[nn]);
                            nmea_reader_addc( reader, buff[nn] );
}
                    }
                    //D("\ngps fd event end\n");
                }
                else
                {
                    LOGE("epoll_wait() returned unkown fd %d ?", fd);
                }
            }
        }
    }
Exit:
    D("%s Exit\n", __FUNCTION__);
    return NULL;
}

static void
gps_state_init( GpsState*  state )
{
    state->init       = 1;
    state->control[0] = -1;
    state->control[1] = -1;
    state->fd         = -1;
D("%s: GPS hardware init !!\n", __FUNCTION__);
    if (sem_init(&state->fix_sem, 0, 1) != 0) {
      D("gps semaphore initialization failed! errno = %d", errno);
      return;
    }
    //state->fd = qemud_channel_open(QEMU_CHANNEL_NAME);
    state->fd = open(GPS_Serial_Name, O_RDONLY );//frank --2011.8.9
    if (state->fd < 0) {
        D("gps Open SerialPort fail\n");
 state->init       = 0;
        return;
    }

// disable echo on serial lines
    if ( isatty( state->fd ) ) {
        struct termios  ios;
        tcgetattr( state->fd, &ios );
        ios.c_lflag = 0;  /* disable ECHO, ICANON, etc... */
        ios.c_oflag &= (~ONLCR); /* Stop \n -> \r\n translation on output */
        ios.c_iflag &= (~(ICRNL | INLCR)); /* Stop \r -> \n & \n -> \r translation on input */
        ios.c_iflag |= (IGNCR | IXOFF);  /* Ignore \r & XON/XOFF on input */
cfsetispeed(&ios, B38400);
    cfsetospeed(&ios, B38400);
        tcsetattr( state->fd, TCSANOW, &ios );
    }

    D("gps emulation will read from '%s' qemud channel", GPS_Serial_Name );
    if ( socketpair( AF_LOCAL, SOCK_STREAM, 0, state->control ) < 0 ) {
        LOGE("could not create thread control socket pair: %s", strerror(errno));
        goto Fail;
    }
/*
    if ( pthread_create( &state->thread, NULL, gps_state_thread, state ) != 0 ) {
        LOGE("could not create gps thread: %s", strerror(errno));
        goto Fail;
    }
*/
    state->thread = state->callbacks.create_thread_cb("qemu_gps",  gps_state_thread, state);

    D("gps state initialized");
    return;
Fail:
    gps_state_done( state );
}

/*****************************************************************/
/*****************************************************************/
/*****                                                       *****/
/*****       I N T E R F A C E                               *****/
/*****                                                       *****/
/*****************************************************************/
/*****************************************************************/
static int
qemu_gps_init(GpsCallbacks* callbacks)
{
    GpsState*  s = _gps_state;
D("%s: GPS init !!\n", __FUNCTION__);

    s->callbacks = *callbacks;
    if (!s->init)
        gps_state_init(s);

    if (s->fd < 0)
        return -1;

   // s->callbacks = *callbacks;
    return 0;
}

static void
qemu_gps_cleanup(void)
{
    GpsState*  s = _gps_state;
D("%s: GPS cleanup !!\n", __FUNCTION__);
    if (s->init)
        gps_state_done(s);
}


static int
qemu_gps_start()
{
    GpsState*  s = _gps_state;

D("%s: GPS start !!\n", __FUNCTION__);
    if (!s->init) {
        D("%s: called with uninitialized state %d!!", __FUNCTION__,s->init);
        return -1;
    }
    D("%s: called", __FUNCTION__);
    gps_state_start(s);
    return 0;
}

static int
qemu_gps_stop()
{
    GpsState*  s = _gps_state;
D("%s: GPS stop !!\n", __FUNCTION__);
    if (!s->init) {
        D("%s: called with uninitialized state !!", __FUNCTION__);
        return -1;
    }

    D("%s: called", __FUNCTION__);
    gps_state_stop(s);
    return 0;
}

static int
qemu_gps_inject_time(GpsUtcTime time, int64_t timeReference, int uncertainty)
{
    D("%s \n", __FUNCTION__);
    return 0;
}

static int
qemu_gps_inject_location(double latitude, double longitude, float accuracy)
{
    D("%s \n", __FUNCTION__);
    return 0;
}

static void
qemu_gps_delete_aiding_data(GpsAidingData flags)
{
    D("%s \n", __FUNCTION__);
}

static int qemu_gps_set_position_mode(GpsPositionMode mode, int fix_frequency)
{
    // FIXME - support fix_frequency
    
    D("%s \n", __FUNCTION__);
    return 0;
}

static const GpsInterface  qemuGpsInterface = {
    sizeof(GpsInterface),
    qemu_gps_init,
    qemu_gps_start,
    qemu_gps_stop,
    qemu_gps_cleanup,
    qemu_gps_inject_time,
    qemu_gps_inject_location,
    qemu_gps_delete_aiding_data,
    qemu_gps_set_position_mode,
    qemu_gps_get_extension,
};

static const void*
qemu_gps_get_extension(const char* name)
{
    // no extensions supported
    
    D("%s : %s\n", __FUNCTION__,name);
    return &qemuGpsInterface;
    //return NULL;
}

const GpsInterface* gps__get_gps_interface(struct gps_device_t* dev)
{
    return &qemuGpsInterface;
}

static int open_gps(const struct hw_module_t* module, char const* name,
        struct hw_device_t** device)
{
    struct gps_device_t *dev = malloc(sizeof(struct gps_device_t));
    memset(dev, 0, sizeof(*dev));
    D("%s: GPS OPEN !!\n", __FUNCTION__);

    dev->common.tag = HARDWARE_DEVICE_TAG;
    dev->common.version = 0;
    dev->common.module = (struct hw_module_t*)module;
//    dev->common.close = (int (*)(struct hw_device_t*))close_lights;
    dev->get_gps_interface = gps__get_gps_interface;

    *device = (struct hw_device_t*)dev;
    return 0;
}

static struct hw_module_methods_t gps_module_methods = {
    .open = open_gps
};

const struct hw_module_t HAL_MODULE_INFO_SYM = {
    .tag = HARDWARE_MODULE_TAG,
    .version_major = 1,
    .version_minor = 0,
    .id = GPS_HARDWARE_MODULE_ID,
    .name = "Goldfish GPS Module",
    .author = "The Android Open Source Project",
    .methods = &gps_module_methods,
};