Rework to add and use a binding for radio control

A radio binding has been added in the new binding directory, and the
application has been reworked to use it.  The binding uses a modified
version of the rtl_fm code used in the qtmultimedia radio plugin that
was previously used, and some new code has been added to output to
PulseAudio using the asynchronous API to ensure compatibility with
stream corking.  The rtl_fm code has been enhanced to add seeking
support, and the application has been tweaked to use it.

Bug-AGL: SPEC-581

Change-Id: I011e98374accc2cad2b36c93ac800948ee51f2aa
Signed-off-by: Scott Murray <scott.murray@konsulko.com>

1 files changed, 254 insertions, 0 deletions

diff --git a/radio_impl_rtlsdr.c b/radio_impl_rtlsdr.c
new file mode 100644
index 0000000..4364fd5
--- /dev/null
+++ b/radio_impl_rtlsdr.c
@@ -0,0 +1,254 @@
+/*
+ * Copyright (C) 2017 Konsulko Group
+ *
+ * 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.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+#include <glib.h>
+
+#include "radio_impl.h"
+#include "radio_output.h"
+#include "rtl_fm.h"
+
+// Structure to describe FM band plans, all values in Hz.
+typedef struct {
+	char *name;
+	uint32_t min;
+	uint32_t max;
+	uint32_t step;
+} fm_band_plan_t;
+
+static fm_band_plan_t known_fm_band_plans[5] = {
+	{ .name = "US", .min = 87900000, .max = 107900000, .step = 200000 },
+	{ .name = "JP", .min = 76100000, .max = 89900000, .step = 100000 },
+	{ .name = "EU", .min = 87500000, .max = 108000000, .step = 50000 },
+	{ .name = "ITU-1", .min = 87500000, .max = 108000000, .step = 50000 },
+	{ .name = "ITU-2", .min = 87900000, .max = 107900000, .step = 50000 }
+};
+
+static unsigned int bandplan;
+static bool present;
+static bool active;
+static uint32_t current_frequency;
+
+static void rtl_output_callback(int16_t *result, int result_len, void *ctx)
+{
+    if(active)
+	    radio_output_write((char*) result, result_len * 2);
+}
+
+int radio_impl_init(void)
+{
+	GKeyFile* conf_file;
+	int conf_file_present = 0;
+	char *value_str;
+
+	if(present)
+		return -1;
+
+	// Load settings from configuration file if it exists
+	conf_file = g_key_file_new();
+	if(conf_file &&
+	   g_key_file_load_from_dirs(conf_file,
+				     "AGL.conf",
+				     (const gchar**) g_get_system_config_dirs(),
+				     NULL,
+				     G_KEY_FILE_KEEP_COMMENTS,
+				     NULL) == TRUE) {
+		conf_file_present = 1;
+
+		// Set band plan if it is specified
+		value_str = g_key_file_get_string(conf_file,
+						  "radio",
+						  "fmbandplan",
+						  NULL);
+		if(value_str) {
+			unsigned int i;
+			for(i = 0;
+			    i < sizeof(known_fm_band_plans) / sizeof(fm_band_plan_t);
+			    i++) {
+				if(!strcasecmp(value_str, known_fm_band_plans[i].name)) {
+					bandplan = i;
+					break;
+				}
+			}
+		}
+	}
+	fprintf(stderr, "Using FM Bandplan: %s\n", known_fm_band_plans[bandplan].name);
+
+	current_frequency = radio_impl_get_min_frequency(BAND_FM);
+	if(rtl_fm_init(current_frequency, 200000, 48000, rtl_output_callback, NULL) < 0) {
+		return -1;
+	}
+
+	if(conf_file_present) {
+		GError *error = NULL;
+		int n;
+
+		// Allow over-riding scanning parameters just in case a demo
+		// setup needs to do so to work reliably.
+		n = g_key_file_get_integer(conf_file,
+					   "radio",
+					   "scan_squelch_level",
+					   &error);
+		//error->code != G_KEY_FILE_ERROR_KEY_NOT_FOUND &&
+		//error->code != G_KEY_FILE_ERROR_INVALID_VALUE) {
+		if(!error) {
+			fprintf(stderr, "Scanning squelch level set to %d\n", n);
+			rtl_fm_scan_set_squelch_level(n);
+		}
+
+		error = NULL;
+		n = g_key_file_get_integer(conf_file,
+					   "radio",
+					   "scan_squelch_limit",
+					   &error);
+		if(!error) {
+			fprintf(stderr, "Scanning squelch limit set to %d\n", n);
+			rtl_fm_scan_set_squelch_limit(n);
+		}
+
+		g_key_file_free(conf_file);
+	}
+
+	present = true;
+	return 0;
+}
+
+uint32_t radio_impl_get_frequency(void)
+{
+	return current_frequency;
+}
+
+void radio_impl_set_frequency(uint32_t frequency)
+{
+	if(!present)
+		return;
+
+	if(frequency < known_fm_band_plans[bandplan].min ||
+	   frequency > known_fm_band_plans[bandplan].max)
+		return;
+
+	radio_impl_scan_stop();
+	current_frequency = frequency;
+	rtl_fm_set_freq(frequency);
+}
+
+void radio_impl_set_frequency_callback(radio_freq_callback_t callback,
+				       void *data)
+{
+	rtl_fm_set_freq_callback(callback, data);
+}
+
+radio_band_t radio_impl_get_band(void)
+{
+	return BAND_FM;
+}
+
+void radio_impl_set_band(radio_band_t band)
+{
+	// We only support FM, so do nothing
+}
+
+int radio_impl_band_supported(radio_band_t band)
+{
+	if(band == BAND_FM)
+		return 1;
+	return 0;
+}
+
+uint32_t radio_impl_get_min_frequency(radio_band_t band)
+{
+	return known_fm_band_plans[bandplan].min;
+}
+
+uint32_t radio_impl_get_max_frequency(radio_band_t band)
+{
+	return known_fm_band_plans[bandplan].max;
+}
+
+uint32_t radio_impl_get_frequency_step(radio_band_t band)
+{
+	uint32_t ret = 0;
+
+	switch (band) {
+	case BAND_AM:
+		ret = 1000; // 1 kHz
+		break;
+	case BAND_FM:
+		ret = known_fm_band_plans[bandplan].step;
+		break;
+	default:
+		break;
+	}
+	return ret;
+}
+
+void radio_impl_start(void)
+{
+	if(!present)
+		return;
+
+	if(!active) {
+		if(radio_output_start() != 0)
+			return;
+
+		rtl_fm_start();
+		active = true;
+	}
+}
+
+void radio_impl_stop(void)
+{
+	if(!present)
+		return;
+
+	if(active) {
+		active = false;
+		radio_output_stop();
+		rtl_fm_stop();
+
+	}
+}
+
+void radio_impl_scan_start(radio_scan_direction_t direction,
+			   radio_scan_callback_t callback,
+			   void *data)
+{
+	rtl_fm_scan_start(direction == SCAN_FORWARD ? 0 : 1,
+			  callback,
+			  data,
+			  radio_impl_get_frequency_step(BAND_FM),
+			  radio_impl_get_min_frequency(BAND_FM),
+			  radio_impl_get_max_frequency(BAND_FM));
+}
+
+void radio_impl_scan_stop(void)
+{
+	rtl_fm_scan_stop();
+}
+
+radio_stereo_mode_t radio_impl_get_stereo_mode(void)
+{
+	return STEREO;
+}
+
+void radio_impl_set_stereo_mode(radio_stereo_mode_t mode)
+{
+	// We only support stereo, so do nothing
+}