devices: unify band handling

This is basically common, but optional code.

Change-Id: I64f5a462451e967d4750d8e4f1d5832cbab41cff

2 files changed, 134 insertions, 1 deletions

diff --git a/Transceiver52M/device/common/Makefile.am b/Transceiver52M/device/common/Makefile.am
index 4d29e98..1a33592 100644
--- a/Transceiver52M/device/common/Makefile.am
+++ b/Transceiver52M/device/common/Makefile.am
@@ -4,7 +4,7 @@ AM_CPPFLAGS = -Wall $(STD_DEFINES_AND_INCLUDES)
 AM_CXXFLAGS = -lpthread $(LIBOSMOCORE_CFLAGS)
 
 
-noinst_HEADERS = radioDevice.h smpl_buf.h
+noinst_HEADERS = radioDevice.h smpl_buf.h bandmanager.h
 
 noinst_LTLIBRARIES = libdevice_common.la
 
diff --git a/Transceiver52M/device/common/bandmanager.h b/Transceiver52M/device/common/bandmanager.h
new file mode 100644
index 0000000..a198937
--- /dev/null
+++ b/Transceiver52M/device/common/bandmanager.h
@@ -0,0 +1,133 @@
+#pragma once
+/*
+ * (C) 2022 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
+ * All Rights Reserved
+ *
+ * Author: Eric Wild <ewild@sysmocom.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <string>
+#include <tuple>
+
+#include "Logger.h"
+
+extern "C" {
+#include <osmocom/gsm/gsm_utils.h>
+}
+
+template <typename powermapt, typename devmapt>
+class band_manager {
+	using powerkeyt = typename powermapt::key_type;
+	using powermappedt = typename powermapt::mapped_type;
+	using devkeyt = typename devmapt::key_type;
+	const devkeyt &m_dev_type;
+	const powermapt &m_power_map;
+	const devmapt &m_dev_map;
+	powerkeyt m_fallback;
+	enum gsm_band m_band;
+	powermappedt m_band_desc;
+	bool band_ass_curr_sess{}; /* true if  "band" was set after last POWEROFF */
+
+	// looks up either first tuple element (->enum) or straight enum
+	template <typename T, typename std::enable_if<std::is_enum<T>::value>::type *dummy = nullptr>
+	auto key_helper(T &t) -> T
+	{
+		return t;
+	}
+
+	template <typename T>
+	auto key_helper(T t) -> typename std::tuple_element<0, T>::type
+	{
+		return std::get<0>(t);
+	}
+
+	void assign_band_desc(enum gsm_band req_band)
+	{
+		auto key = key_helper(m_dev_type);
+		auto fallback_key = key_helper(m_fallback);
+		auto it = m_power_map.find({ key, req_band });
+		if (it == m_power_map.end()) {
+			auto desc = m_dev_map.at(m_dev_type);
+			LOGC(DDEV, ERROR) << "No Tx Power measurements exist for device " << desc.desc_str
+					  << " on band " << gsm_band_name(req_band) << ", using fallback..";
+			it = m_power_map.find({ fallback_key, req_band });
+		}
+		OSMO_ASSERT(it != m_power_map.end());
+		m_band_desc = it->second;
+	}
+
+	bool set_band(enum gsm_band req_band)
+	{
+		if (band_ass_curr_sess && req_band != m_band) {
+			LOGC(DDEV, ALERT) << "Requesting band " << gsm_band_name(req_band)
+					  << " different from previous band " << gsm_band_name(m_band);
+			return false;
+		}
+
+		if (req_band != m_band) {
+			m_band = req_band;
+			assign_band_desc(m_band);
+		}
+		band_ass_curr_sess = true;
+		return true;
+	}
+
+    public:
+	band_manager(const devkeyt &dev_type, const powermapt &power_map, const devmapt &dev_map, powerkeyt fallback)
+		: m_dev_type(dev_type), m_power_map(power_map), m_dev_map(dev_map), m_fallback(fallback),
+		  m_band((enum gsm_band)0)
+	{
+	}
+	band_manager(const powermapt &power_map, const devmapt &dev_map)
+		: m_dev_type(dev_map.begin()->first), m_power_map(power_map), m_dev_map(dev_map),
+		  m_fallback(m_power_map.begin()->first), m_band((enum gsm_band)0)
+	{
+	}
+	void band_reset()
+	{
+		band_ass_curr_sess = false;
+	}
+
+	void get_dev_band_desc(powermappedt &desc)
+	{
+		if (m_band == 0) {
+			LOGC(DDEV, ERROR)
+				<< "Power parameters requested before Tx Frequency was set! Providing band 900 by default...";
+			assign_band_desc(GSM_BAND_900);
+		}
+		desc = m_band_desc;
+	}
+
+	bool update_band_from_freq(double wFreq, int chan, bool is_tx)
+	{
+		enum gsm_band req_band;
+		auto dirstr = is_tx ? "Tx" : "Rx";
+		auto req_arfcn = gsm_freq102arfcn(wFreq / 1000 / 100, !is_tx);
+		if (req_arfcn == 0xffff) {
+			LOGCHAN(chan, DDEV, ALERT)
+				<< "Unknown ARFCN for " << dirstr << " Frequency " << wFreq / 1000 << " kHz";
+			return false;
+		}
+		if (gsm_arfcn2band_rc(req_arfcn, &req_band) < 0) {
+			LOGCHAN(chan, DDEV, ALERT) << "Unknown GSM band for " << dirstr << " Frequency " << wFreq
+						   << " Hz (ARFCN " << req_arfcn << " )";
+			return false;
+		}
+
+		return set_band(req_band);
+	}
+};
\ No newline at end of file