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-rw-r--r--radio_impl_rtlsdr.c254
1 files changed, 254 insertions, 0 deletions
diff --git a/radio_impl_rtlsdr.c b/radio_impl_rtlsdr.c
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+/*
+ * 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
+}