Rework hardware probing and RTL-SDR helper startup

The lazy startup of the separate helper program for the RTL-SDR
backend on playback start was incorrect with respect to the expected
behavior the frequency setting verbs.  This was not visible during
usage by the radio application, but was triggering failures in
several tests in the pyagl binding wrapper test suite.  To facilitate
starting the helper during backend initialization, the probing part
of the backend "init" has been split into a separate "probe" function,
and all backends have been updated to reflect this change.  Logic has
been added to enforce that "init" is only called after "probe" has
succeeded for a backend, and a comment has been added to radio_impl.h
to document this intended behavior.

Bug-AGL: SPEC-3717

Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Change-Id: Ic37331a92bae7cc01ee448e69894fa5f49d08a74

1 files changed, 34 insertions, 12 deletions

diff --git a/binding/radio_impl_tef665x.c b/binding/radio_impl_tef665x.c
index 504f155..9bad684 100644
--- a/binding/radio_impl_tef665x.c
+++ b/binding/radio_impl_tef665x.c
@@ -137,9 +137,10 @@ static band_plan_t known_am_band_plans[1] = {
 
 static unsigned int fm_bandplan = 2;
 static unsigned int am_bandplan = 0;
-static bool corking = false;
-static bool present = false;
-static bool scanning = false;
+static bool corking;
+static bool present;
+static bool initialized;
+static bool scanning;
 
 // stream state
 static GstElement *pipeline;
@@ -1626,7 +1627,8 @@ static int i2c_init(const char *i2c, int state, uint32_t *i2c_file_desc)
 static void tef665x_start(void)
 {
 	int ret;
-	 if(!present)
+
+	if(!initialized)
 		return;
 
 	_debug("file_desc ", file_desc);
@@ -2078,7 +2080,7 @@ static void tef665x_stop(void)
 	GstEvent *event;
 	audio_set_mute(file_desc, 1);
 
-	 if(present && running) {
+	 if(initialized && running) {
 		// Stop pipeline
 		running = false;
 		ret = gst_element_set_state(pipeline, GST_STATE_PAUSED);
@@ -2093,13 +2095,12 @@ static void tef665x_stop(void)
 	}
 }
 
-static int tef665x_init()
+static int tef665x_probe()
 {
-	char gst_pipeline_str[GST_PIPELINE_LEN];
 	int rc;
 
-	current_am_frequency = known_am_band_plans[am_bandplan].min;
-	current_fm_frequency = known_fm_band_plans[fm_bandplan].min;
+	if(present)
+		return 0;
 
 	rc = i2c_init(I2C_DEV, _open, &file_desc);
 	if(rc < 0) {
@@ -2114,6 +2115,24 @@ static int tef665x_init()
 		return -1;
 	}
 
+	present = true;
+	return 0;
+}
+
+static int tef665x_init()
+{
+	char gst_pipeline_str[GST_PIPELINE_LEN];
+	int rc;
+
+	if(!present)
+		return -1;
+
+	if(initialized)
+		return 0;
+
+	current_am_frequency = known_am_band_plans[am_bandplan].min;
+	current_fm_frequency = known_fm_band_plans[fm_bandplan].min;
+
 	current_band = BAND_AM;
 
 	radio_powerSwitch(file_desc, 1);
@@ -2150,12 +2169,12 @@ static int tef665x_init()
 	rc = gst_bus_add_watch(gst_element_get_bus(pipeline), (GstBusFunc) handle_message, NULL);
 	_debug("gst_bus_add_watch   rc", rc);
 
-	present = true;
-
 	//Initialize Mutex Lock for Scan and RDS
 	pthread_mutex_init(&scan_mutex, NULL);
 	pthread_mutex_init (&RDS_Mutex, NULL);
 
+	initialized = true;
+
 	tef665x_start();
 	return 0;
 }
@@ -2226,7 +2245,8 @@ static void tef665x_set_alternative_frequency(uint32_t frequency)
 static void tef665x_set_frequency(uint32_t frequency)
 {
 	uint32_t fd = 0;
-	if(!present)
+
+	if(!initialized)
 		return;
 
 	if(scanning)
@@ -2357,8 +2377,10 @@ static uint32_t tef665x_get_frequency_step(radio_band_t band)
 	}
 	return ret;
 }
+
 radio_impl_ops_t tef665x_impl_ops = {
 	.name = "TEF665x",
+	.probe = tef665x_probe,
 	.init = tef665x_init,
 	.start = tef665x_start,
 	.stop = tef665x_stop,