Add a new capability to the generic driver structure: wakeup...

...a function to be called just after the autobaud hunt sets the line
speed each time.  Use this to get rid of the internal baud hunt loop
in the True North driver; instead, the ID query and rate-setting
strings will be sent by the wakeup hook.

Note: this patch is untested.  I'm pretty certain it will work, but
somebody needs to try it on live hardware.

1 files changed, 18 insertions, 90 deletions

diff --git a/truenorth.c b/truenorth.c
index c207542f..853073c5 100644
--- a/truenorth.c
+++ b/truenorth.c
@@ -29,10 +29,6 @@
 
 #ifdef TNT_ENABLE
 
-enum {
-#include "packet_states.h"
-};
-
 static void tnt_add_checksum(char *sentence)
 {
     unsigned char sum = '\0';
@@ -73,101 +69,33 @@ static int tnt_send(int fd, const char *fmt, ... )
     }
 }
 
-#define TNT_SNIFF_RETRIES       100
 /*
- * The True North compass won't start talking
- * unless you ask it to. So to identify it we
- * need to query for it's ID string.
+ * The True North compass won't start talking unless you ask it to. To
+ * wake it up, we query for its ID string just after each speed change
+ * in the autobaud hunt.  Then we send codes to start the flow of data.
  */
-static int tnt_packet_sniff(struct gps_device_t *session)
-{
-    unsigned int n, count = 0;
-
-    gpsd_report(5, "tnt_packet_sniff begins\n");
-    for (n = 0; n < TNT_SNIFF_RETRIES; n++) 
-    {
-      count = 0;
-      (void)tnt_send(session->gpsdata.gps_fd, "@X?");
-      if (ioctl(session->gpsdata.gps_fd, FIONREAD, &count) < 0)
-          return BAD_PACKET;
-      if (count == 0) {
-          //int delay = 10000000000.0 / session->gpsdata.baudrate;
-          //gpsd_report(5, "usleep(%d)\n", delay);
-          //usleep(delay);
-          gpsd_report(5, "sleep(1)\n");
-          (void)sleep(1);
-      } else if (packet_get(session) >= 0) {
-        if((session->packet_type == NMEA_PACKET)&&(session->packet_state == NMEA_RECOGNIZED))
-        {
-          gpsd_report(5, "tnt_packet_sniff returns %d\n",session->packet_type);
-          return session->packet_type;
-        }
-      }
-    }
-
-    gpsd_report(5, "tnt_packet_sniff found no packet\n");
-    return BAD_PACKET;
-}
-
-
-static void tnt_initializer(struct gps_device_t *session)
-{
-  // Send codes to start the flow of data
-  //tnt_send(session->gpsdata.gps_fd, "@BA?"); // Query current rate
-  //tnt_send(session->gpsdata.gps_fd, "@BA=8"); // Start HTM packet at 1Hz
-  /*
-   * Sending this twice seems to make it more reliable!!
-   * I think it gets the input on the unit synced up.
-   */
-  (void)tnt_send(session->gpsdata.gps_fd, "@BA=15"); // Start HTM packet at 1200 per minute
-  (void)tnt_send(session->gpsdata.gps_fd, "@BA=15"); // Start HTM packet at 1200 per minute
-}
-
-static bool tnt_probe(struct gps_device_t *session)
+static int tnt_wakeup(struct gps_device_t *session)
 {
-  unsigned int *ip;
-#ifdef FIXED_PORT_SPEED
-    /* just the one fixed port speed... */
-    static unsigned int rates[] = {FIXED_PORT_SPEED};
-#else /* FIXED_PORT_SPEED not defined */
-  /* The supported baud rates */
-  static unsigned int rates[] = {38400, 19200, 2400, 4800, 9600 };
-#endif /* FIXED_PORT_SPEED defined */
-
-  gpsd_report(1, "Probing TrueNorth Compass\n");
-
-  /*
-   * Only block until we get at least one character, whatever the
-   * third arg of read(2) says.
-   */
-  /*@ ignore @*/
-  memset(session->ttyset.c_cc,0,sizeof(session->ttyset.c_cc));
-  session->ttyset.c_cc[VMIN] = 1;
-  /*@ end @*/
-
-  session->ttyset.c_cflag &= ~(PARENB | PARODD | CRTSCTS);
-  session->ttyset.c_cflag |= CREAD | CLOCAL;
-  session->ttyset.c_iflag = session->ttyset.c_oflag = session->ttyset.c_lflag = (tcflag_t) 0;
-
-  session->baudindex = 0;
-  for (ip = rates; ip < rates + sizeof(rates)/sizeof(rates[0]); ip++)
-      if (ip == rates || *ip != rates[0])
-      {
-          gpsd_report(1, "hunting at speed %d\n", *ip);
-          gpsd_set_speed(session, *ip, 'N',1);
-          if (tnt_packet_sniff(session) != BAD_PACKET)
-              return true;
-      }
-  return false;
+    (void)tnt_send(session->gpsdata.gps_fd, "@X?");
+    //tnt_send(session->gpsdata.gps_fd, "@BA?"); // Query current rate
+    //tnt_send(session->gpsdata.gps_fd, "@BA=8"); // Start HTM packet at 1Hz
+    /*
+     * Sending this twice seems to make it more reliable!!
+     * I think it gets the input on the unit synced up.
+     * The intent is to start HTM packet reporting at 1200 per minute.
+     */
+    (void)tnt_send(session->gpsdata.gps_fd, "@BA=15");
+    (void)tnt_send(session->gpsdata.gps_fd, "@BA=15");
 }
 
 struct gps_type_t trueNorth = {
     .typename       = "True North",	/* full name of type */
     .trigger        = " TNT1500",
     .channels       = 0,		/* not an actual GPS at all */
-    .probe          = tnt_probe,	/* probe by sending ID query */
-    .initializer    = tnt_initializer,	/* probe for True North Digital Compass */
-    .get_packet     = packet_get,		/* how to get a packet */
+    .wakeup         = tnt_wakeup,	/* wakeup by sending ID query */
+    .probe          = NULL,		/* no probe */
+    .initializer    = NULL,		/* no initializer */
+    .get_packet     = packet_get,	/* how to get a packet */
     .parse_packet   = nmea_parse_input,	/* how to interpret a packet */
     .rtcm_writer    = NULL,	        /* Don't send */
     .speed_switcher = NULL,		/* no speed switcher */