Repurpose into gRPC service

Repurpose repository into a spiritual successor of the previous
binding.  The backend code is retained behind a new gRPC API
defined in protos/radio.proto.  The simpler synchronous gRPC API
had been used for expediency, this may warrant revisiting to
rework into an async or callback API based server instead.  As
well, authentication has been left until some consensus on an
approach can be worked out.

Bug-AGL: SPEC-4665

Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Change-Id: I28b122ce6e0ecfc7504aa08b90394cb1b9e22976
(cherry picked from commit dd23c157bdba1b25bbb50cdb99a60aa597735f43)

1 files changed, 279 insertions, 0 deletions

diff --git a/src/radio_impl_null.c b/src/radio_impl_null.c
new file mode 100644
index 0000000..60dbab2
--- /dev/null
+++ b/src/radio_impl_null.c
@@ -0,0 +1,279 @@
+/*
+ * Copyright (C) 2017,2018,2020 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.
+ */
+
+/*
+ * NOTE: Some locking around frequency and scanning state may be
+ *       required if this null implementation ever needs to be used
+ *       beyond basic functionality testing.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+#include <strings.h>
+#include <unistd.h>
+#include <pthread.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <glib.h>
+
+#include "radio_impl.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 = 76000000, .max = 95000000, .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 initialized;
+static bool active;
+static bool scanning;
+static uint32_t current_frequency;
+static radio_freq_callback_t freq_callback;
+static void *freq_callback_data;
+
+static uint32_t null_get_min_frequency(radio_band_t band);
+static void null_set_frequency(uint32_t frequency);
+
+static int null_probe(void)
+{
+	present = true;
+	return 0;
+}
+
+static int null_init(void)
+{
+	GKeyFile *conf_file;
+	char *value_str;
+
+	if(!present)
+		return -1;
+
+	if(initialized)
+		return 0;
+
+	// 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) {
+
+		// 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;
+				}
+			}
+		}
+	}
+
+	// Start off with minimum bandplan frequency
+	current_frequency = null_get_min_frequency(RADIO_BAND_FM);
+
+	initialized = true;
+	null_set_frequency(current_frequency);
+
+	return 0;
+}
+
+static void null_set_output(const char *output)
+{
+}
+
+static uint32_t null_get_frequency(void)
+{
+	return current_frequency;
+}
+
+static void null_set_frequency(uint32_t frequency)
+{
+	if(frequency < known_fm_band_plans[bandplan].min ||
+	   frequency > known_fm_band_plans[bandplan].max)
+		return;
+
+	current_frequency = frequency;
+
+	if(freq_callback)
+		freq_callback(current_frequency, freq_callback_data);
+}
+
+static void null_set_frequency_callback(radio_freq_callback_t callback,
+					void *data)
+{
+	freq_callback = callback;
+	freq_callback_data = data;
+}
+
+static radio_band_t null_get_band(void)
+{
+	// We only support FM
+	return RADIO_BAND_FM;
+}
+
+static void null_set_band(radio_band_t band)
+{
+	// We only support FM, so do nothing
+}
+
+static int null_band_supported(radio_band_t band)
+{
+	if(band == RADIO_BAND_FM)
+		return 1;
+	return 0;
+}
+
+static uint32_t null_get_min_frequency(radio_band_t band)
+{
+	return known_fm_band_plans[bandplan].min;
+}
+
+static uint32_t null_get_max_frequency(radio_band_t band)
+{
+	return known_fm_band_plans[bandplan].max;
+}
+
+static uint32_t null_get_frequency_step(radio_band_t band)
+{
+	uint32_t ret = 0;
+
+	switch (band) {
+	case RADIO_BAND_AM:
+		ret = 1000; // 1 kHz
+		break;
+	case RADIO_BAND_FM:
+		ret = known_fm_band_plans[bandplan].step;
+		break;
+	default:
+		break;
+	}
+	return ret;
+}
+
+static void null_start(void)
+{
+	if(!initialized)
+		return;
+
+	if(active)
+		return;
+
+	active = true;
+}
+
+static void null_stop(void)
+{
+	if(!initialized)
+		return;
+
+	if (!active)
+		return;
+
+	active = false;
+}
+
+static void null_scan_start(radio_scan_direction_t direction,
+			    radio_scan_callback_t callback,
+			    void *data)
+{
+	int frequency;
+
+	if(!active || scanning)
+		return;
+
+	scanning = true;
+
+	// Just go to the next frequency step up or down
+	frequency = current_frequency;
+	if(direction == RADIO_SCAN_FORWARD) {
+		frequency += known_fm_band_plans[bandplan].step;
+	} else {
+		frequency -= known_fm_band_plans[bandplan].step;
+	}
+	if(frequency < known_fm_band_plans[bandplan].min)
+		frequency = known_fm_band_plans[bandplan].max;
+	else if(frequency > known_fm_band_plans[bandplan].max)
+		frequency = known_fm_band_plans[bandplan].min;
+
+	scanning = false;
+	null_set_frequency(frequency);
+	if(callback)
+		callback(frequency, data);
+}
+
+static void null_scan_stop(void)
+{
+	scanning = false;
+}
+
+static radio_stereo_mode_t null_get_stereo_mode(void)
+{
+	// We only support stereo
+	return RADIO_MODE_STEREO;
+}
+
+static void null_set_stereo_mode(radio_stereo_mode_t mode)
+{
+	// We only support stereo, so do nothing
+}
+
+radio_impl_ops_t null_impl_ops = {
+	.name = "null/mock radio",
+	.probe = null_probe,
+	.init = null_init,
+	.set_output = null_set_output,
+	.get_frequency = null_get_frequency,
+	.set_frequency = null_set_frequency,
+	.set_frequency_callback = null_set_frequency_callback,
+	.get_band = null_get_band,
+	.set_band = null_set_band,
+	.band_supported = null_band_supported,
+	.get_min_frequency = null_get_min_frequency,
+	.get_max_frequency = null_get_max_frequency,
+	.get_frequency_step = null_get_frequency_step,
+	.start = null_start,
+	.stop = null_stop,
+	.scan_start = null_scan_start,
+	.scan_stop = null_scan_stop,
+	.get_stereo_mode = null_get_stereo_mode,
+	.set_stereo_mode = null_set_stereo_mode
+};