Add audio role open/close support

Rework things so that the 4A audio role is only opened while playing,
and closed when stopped.  Further work will need to be done to handle
the possibility of the output device changing on subsequent opens,
both the RTL SDR and Kingfisher case have complications around doing
so:
- The RTL SDR helper application needs to be enhanced to add an
  output setting command.  Killing it and starting it again would
  also work, but likely will add noticeable UI latency.
- On the Kingfisher, the binding currently has no control over the
  output used for the loopback, as it is being set up down in the
  soft-mixer based on HAL values.

Change-Id: I4aa83c937972ec5d91f7b78421a11148c7fe0afc
Signed-off-by: Scott Murray <scott.murray@konsulko.com>
(cherry picked from commit f1d5902c92eafd3aad62e29298502603a9b56d81)

1 files changed, 78 insertions, 69 deletions

diff --git a/binding/radio-binding.c b/binding/radio-binding.c
index 5f67567..490af5b 100644
--- a/binding/radio-binding.c
+++ b/binding/radio-binding.c
@@ -20,6 +20,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdint.h>
+#include <stdbool.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <json-c/json.h>
@@ -53,6 +54,67 @@ static void scan_callback(uint32_t frequency, void *data)
 	afb_event_push(scan_event, json_object_get(jresp));
 }
 
+static int set_role_state(bool state, char **output)
+{
+	int rc;
+	json_object *response = NULL;
+	json_object *jsonData = json_object_new_object();
+
+	json_object_object_add(jsonData, "action", json_object_new_string(state ? "open" : "close"));
+	rc = afb_service_call_sync("ahl-4a", "radio", jsonData, &response);
+	if (rc < 0) {
+		AFB_ERROR("Failed to %s 4A 'radio' role", state ? "open" : "close");
+		goto failed;
+	}
+
+	if(!state) {
+		// No need to look at the response on close
+		goto done;
+	}
+
+	// Handle response on open
+	json_object *valJson = NULL;
+	json_object *val = NULL;
+	rc = json_object_object_get_ex(response, "response", &valJson);
+	if (rc == 0) {
+		AFB_ERROR("Reply from 4A is missing a 'response' field");
+		rc = -1;
+		goto failed_malformed;
+	}
+
+	rc = json_object_object_get_ex(valJson, "device_uri", &val);
+	if (rc == 0) {
+		AFB_ERROR("Reply from 4A is missing a 'device_uri' field");
+		rc = -1;
+		goto failed_malformed;
+	}
+
+	const char *jres_pcm = json_object_get_string(val);
+	char * p = strchr(jres_pcm, ':');
+
+	if (p == NULL) {
+		AFB_ERROR("Unable to parse 'device_uri' value field");
+		rc = -1;
+		goto failed_malformed;
+	}
+
+	if (output) {
+		if (asprintf(output, "hw:%s", p + 1) < 0) {
+			AFB_ERROR("Insufficient memory");
+			rc = -1;
+			goto failed_malformed;
+		}
+	}
+done:
+	rc = 0;
+
+failed_malformed:
+	json_object_put(response);
+
+failed:
+	return rc;
+}
+
 /*
  * Binding verb handlers
  */
@@ -306,7 +368,13 @@ static void frequency_step(struct afb_req request)
  */
 static void start(struct afb_req request)
 {
-	radio_impl_ops->start();
+	char *output = NULL;
+
+	if(set_role_state(true, &output) == 0) {
+		radio_impl_ops->set_output(output);
+		radio_impl_ops->start();
+		free(output);
+	}
 	afb_req_success(request, NULL, NULL);
 }
 
@@ -319,6 +387,7 @@ static void start(struct afb_req request)
 static void stop(struct afb_req request)
 {
 	radio_impl_ops->stop();
+	set_role_state(false, NULL);
 	afb_req_success(request, NULL, NULL);
 }
 
@@ -487,89 +556,29 @@ static const struct afb_verb_v2 verbs[]= {
 
 static int init()
 {
-	int rc;
-	char *output = NULL;
-
-#ifdef HAVE_4A_FRAMEWORK
-	json_object *response = NULL;
-	json_object *jsonData = json_object_new_object();
-
-	json_object_object_add(jsonData, "action", json_object_new_string("open"));
-	rc = afb_service_call_sync("ahl-4a", "get_roles", NULL, &response);
-	if (rc < 0) {
-		AFB_ERROR("Failed to query 4A about roles");
-		goto failed;
-	}
-	AFB_NOTICE("4A: available roles are '%s'", json_object_get_string(response));
-	json_object_put(response);
-
-	rc = afb_service_call_sync("ahl-4a", "radio", jsonData, &response);
-	if (rc < 0) {
-		AFB_ERROR("Failed to query 'radio' role to 4A");
-		goto failed;
-	}
-
-	json_object *valJson = NULL;
-	json_object *val = NULL;
-
-	rc = json_object_object_get_ex(response, "response", &valJson);
-	if (rc == 0) {
-		AFB_ERROR("Reply from 4A is missing a 'response' field");
-		goto failed_malformed;
-	}
-
-	rc = json_object_object_get_ex(valJson, "device_uri", &val);
-	if (rc == 0) {
-		AFB_ERROR("Reply from 4A is missing a 'device_uri' field");
-		goto failed_malformed;
-	}
-
-	const char *jres_pcm = json_object_get_string(val);
-	char * p = strchr(jres_pcm, ':');
-
-	if (p == NULL) {
-		AFB_ERROR("Unable to parse 'device_uri' value field");
-		rc = -1;
-		goto failed_malformed;
-	}
-
-	if (asprintf(&output, "hw:%s", p + 1) < 0) {
-		AFB_ERROR("Insufficient memory");
-		rc = -1;
-		goto failed_malformed;
-	}
-#endif /* HAVE_4A_FRAMEWORK */
-
-	// Initialize event structures
-	freq_event = afb_daemon_make_event("frequency");
-	scan_event = afb_daemon_make_event("station_found");
-
 	// Look for RTL-SDR USB adapter
 	radio_impl_ops = &rtlsdr_impl_ops;
-	rc = radio_impl_ops->init(output);
+	int rc = radio_impl_ops->init();
 	if(rc != 0) {
 		// Look for Kingfisher Si4689
 		radio_impl_ops = &kf_impl_ops;
-		rc = radio_impl_ops->init(output);
+		rc = radio_impl_ops->init();
 	}
 	if (rc != 0) {
 		AFB_ERROR("No radio device found, exiting");
-		goto failed;
 	}
-
 	if(rc == 0) {
 		AFB_NOTICE("%s found\n", radio_impl_ops->name);
 		radio_impl_ops->set_frequency_callback(freq_callback, NULL);
+	} else {
+		return rc;
 	}
-	free(output);
 
-#ifdef HAVE_4A_FRAMEWORK
-failed_malformed:
-	json_object_put(response);
-#endif /* HAVE_4A_FRAMEWORK */
+	// Initialize event structures
+	freq_event = afb_daemon_make_event("frequency");
+	scan_event = afb_daemon_make_event("station_found");
 
-failed:
-	return rc;
+	return 0;
 }
 
 const struct afb_binding_v2 afbBindingV2 = {