altos: Add support for reflashing skytraq GPS chips

This simply switches the skytraq port to 115200 baud and then
essentially connects it directly to the USB port by forwarding bytes
in both directions.

Once started, the only way out is to reboot the board.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/src/drivers/ao_gps_skytraq.c b/src/drivers/ao_gps_skytraq.c
index d80da97c..b7dc0a86 100644
--- a/src/drivers/ao_gps_skytraq.c
+++ b/src/drivers/ao_gps_skytraq.c
@@ -21,6 +21,7 @@
 
 #ifndef ao_gps_getchar
 #define ao_gps_getchar	ao_serial1_getchar
+#define ao_gps_fifo	ao_serial1_rx_fifo
 #endif
 
 #ifndef ao_gps_putchar
@@ -453,6 +454,8 @@ ao_gps_nmea_parse(void)
 	}
 }
 
+static uint8_t	ao_gps_updating;
+
 void
 ao_gps(void) __reentrant
 {
@@ -468,6 +471,13 @@ ao_gps(void) __reentrant
 		if (ao_gps_getchar() == '$') {
 			ao_gps_nmea_parse();
 		}
+#ifndef AO_GPS_TEST
+		while (ao_gps_updating) {
+			ao_usb_putchar(ao_gps_getchar());
+			if (ao_fifo_empty(ao_gps_fifo))
+				flush();
+		}
+#endif
 	}
 }
 
@@ -492,8 +502,29 @@ gps_dump(void) __reentrant
 	ao_mutex_put(&ao_gps_mutex);
 }
 
+static __code uint8_t ao_gps_115200[] = {
+	SKYTRAQ_MSG_3(5,0,5,0)	/* Set to 115200 baud */
+};
+
+static void
+gps_update(void) __reentrant
+{
+	ao_gps_updating = 1;
+	ao_task_minimize_latency = 1;
+#if HAS_ADC
+	ao_timer_set_adc_interval(0);
+#endif
+	ao_skytraq_sendstruct(ao_gps_115200);
+	ao_gps_set_speed(AO_SERIAL_SPEED_115200);
+
+	/* It's a binary protocol; abandon attempts to escape */
+	for (;;)
+		ao_gps_putchar(ao_usb_getchar());
+}
+
 __code struct ao_cmds ao_gps_cmds[] = {
 	{ gps_dump, 	"g\0Display GPS" },
+	{ gps_update,	"U\0Update GPS firmware" },
 	{ 0, NULL },
 };