sched_lchan_tch_x: use functions to determine AMR tranmssion phase

The AMR transmission phase directly depends on the frame number. The
transmission phase is used to tell if a received AMR frame contains a
CMI (frame type that is currently used) or CMR (frame type that the
receiver should use) codec identifier. The formulas in the present
implementation seem to be correct but they do not reflect the numbers in
the spec very well, nor do they have unit-tests. Lets replace them with
more readble functions and test those functions with unit-tests.

Change-Id: I94a934a6b3b397b4cd0e9da3577325de58814335
Related: SYS#5549

3 files changed, 314 insertions, 0 deletions

diff --git a/tests/amr/Makefile.am b/tests/amr/Makefile.am
new file mode 100644
index 00000000..dc0f1b81
--- /dev/null
+++ b/tests/amr/Makefile.am
@@ -0,0 +1,11 @@
+AM_CPPFLAGS = $(all_includes) -I$(top_srcdir)/include
+AM_CFLAGS = -Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS) $(LIBOSMOCODEC_CFLAGS) \
+	$(LIBOSMOABIS_CFLAGS) $(LIBOSMOTRAU_CFLAGS)
+LDADD = $(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS) $(LIBOSMOCODEC_LIBS) \
+	$(LIBOSMOABIS_LIBS) $(LIBOSMOTRAU_LIBS)
+noinst_PROGRAMS = amr_test
+EXTRA_DIST = amr_test.ok
+
+misc_test_SOURCES = amr_test.c
+misc_test_LDADD = $(top_builddir)/src/common/libbts.a \
+		$(LDADD)
diff --git a/tests/amr/amr_test.c b/tests/amr/amr_test.c
new file mode 100644
index 00000000..4efbf402
--- /dev/null
+++ b/tests/amr/amr_test.c
@@ -0,0 +1,151 @@
+/* (C) 2021 by sysmocom s.f.m.c. GmbH
+ * All Rights Reserved
+ *
+ * Author: Philipp Maier
+ *
+ * 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 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 <osmo-bts/logging.h>
+#include <osmocom/core/utils.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include "../../src/osmo-bts-trx/sched_utils.h"
+
+struct amr_cmi_test_data {
+	/* Frame number that marks the beginning of the voice block */
+	uint32_t gsm_fn;
+	/* In uplink: True, when the voice block is a CMI block, false otherwise. */
+	/* In downlink: False, when the voice block is a CMI block, true otherwise. */
+	bool is_cmi;
+};
+
+/* The behavior of AHS in subslot 0 and AFS is the same */
+static const struct amr_cmi_test_data testvec_ahs_h0_and_afs[] = {
+	{ 0, true },
+	{ 4, false },
+	{ 8, true },
+	{ 13, false },
+	{ 17, true },
+	{ 21, false },
+	{ 26, true },
+	{ 30, false },
+	{ 34, true },
+	{ 39, false },
+	{ 43, true },
+	{ 47, false },
+	{ 52, true },
+	{ 56, false },
+	{ 60, true },
+	{ 65, false },
+	{ 69, true },
+	{ 73, false },
+	{ 78, true },
+	{ 82, false },
+	{ 86, true },
+	{ 91, false },
+	{ 95, true },
+	{ 99, false },
+};
+
+static const struct amr_cmi_test_data testvec_ahs_h1[] = {
+	{ 1, true },
+	{ 5, false },
+	{ 9, true },
+	{ 14, false },
+	{ 18, true },
+	{ 22, false },
+	{ 27, true },
+	{ 31, false },
+	{ 35, true },
+	{ 40, false },
+	{ 44, true },
+	{ 48, false },
+	{ 53, true },
+	{ 57, false },
+	{ 61, true },
+	{ 66, false },
+	{ 70, true },
+	{ 74, false },
+	{ 79, true },
+	{ 83, false },
+	{ 87, true },
+	{ 92, false },
+	{ 96, true },
+	{ 100, false },
+};
+
+static void test_amr_cmi_sched(void)
+{
+	unsigned int i;
+	bool res;
+
+	printf("AMR transmission phase (CMI) in relation to GSM FN:\n");
+
+	for (i = 0; i < ARRAY_SIZE(testvec_ahs_h0_and_afs); i++) {
+		res = ul_amr_fn_is_cmi(testvec_ahs_h0_and_afs[i].gsm_fn);
+		printf("Uplink, AMR AHS on HR subslot 0: fn_begin=%u, CMI=%u\n", testvec_ahs_h0_and_afs[i].gsm_fn, res);
+		OSMO_ASSERT(res == testvec_ahs_h0_and_afs[i].is_cmi);
+	}
+
+	printf("\n");
+
+	for (i = 0; i < ARRAY_SIZE(testvec_ahs_h0_and_afs); i++) {
+		res = dl_amr_fn_is_cmi(testvec_ahs_h0_and_afs[i].gsm_fn);
+		printf("Downlink, AMR AHS on HR subslot 0: fn_begin=%u, CMI=%u\n", testvec_ahs_h0_and_afs[i].gsm_fn, res);
+		OSMO_ASSERT(res == !testvec_ahs_h0_and_afs[i].is_cmi);
+	}
+
+	printf("\n");
+	printf("\n");
+
+	for (i = 0; i < ARRAY_SIZE(testvec_ahs_h1); i++) {
+		res = ul_amr_fn_is_cmi(testvec_ahs_h1[i].gsm_fn);
+		printf("Uplink, AMR AHS on HR subslot 1: fn_begin=%u, CMI=%u\n", testvec_ahs_h1[i].gsm_fn, res);
+		OSMO_ASSERT(res == testvec_ahs_h1[i].is_cmi);
+	}
+
+	printf("\n");
+
+	for (i = 0; i < ARRAY_SIZE(testvec_ahs_h1); i++) {
+		res = dl_amr_fn_is_cmi(testvec_ahs_h1[i].gsm_fn);
+		printf("Downlink, AMR AHS on HR subslot 1: fn_begin=%u, CMI=%u\n", testvec_ahs_h1[i].gsm_fn, res);
+		OSMO_ASSERT(res == !testvec_ahs_h1[i].is_cmi);
+	}
+
+	printf("\n");
+	printf("\n");
+
+	for (i = 0; i < ARRAY_SIZE(testvec_ahs_h0_and_afs); i++) {
+		res = ul_amr_fn_is_cmi(testvec_ahs_h0_and_afs[i].gsm_fn);
+		printf("Uplink, AMR AFS: fn_begin=%u, CMI=%u\n", testvec_ahs_h0_and_afs[i].gsm_fn, res);
+		OSMO_ASSERT(res == testvec_ahs_h0_and_afs[i].is_cmi);
+	}
+
+	printf("\n");
+
+	for (i = 0; i < ARRAY_SIZE(testvec_ahs_h0_and_afs); i++) {
+		res = dl_amr_fn_is_cmi(testvec_ahs_h0_and_afs[i].gsm_fn);
+		printf("Downlink, AMR AFS: fn_begin=%u, CMI=%u\n", testvec_ahs_h0_and_afs[i].gsm_fn, res);
+		OSMO_ASSERT(res == !testvec_ahs_h0_and_afs[i].is_cmi);
+	}
+}
+
+int main(int argc, char **argv)
+{
+
+	test_amr_cmi_sched();
+	return EXIT_SUCCESS;
+}
diff --git a/tests/amr/amr_test.ok b/tests/amr/amr_test.ok
new file mode 100644
index 00000000..ec1d1a08
--- /dev/null
+++ b/tests/amr/amr_test.ok
@@ -0,0 +1,152 @@
+AMR transmission phase (CMI) in relation to GSM FN:
+Uplink, AMR AHS on HR subslot 0: fn_begin=0, CMI=1
+Uplink, AMR AHS on HR subslot 0: fn_begin=4, CMI=0
+Uplink, AMR AHS on HR subslot 0: fn_begin=8, CMI=1
+Uplink, AMR AHS on HR subslot 0: fn_begin=13, CMI=0
+Uplink, AMR AHS on HR subslot 0: fn_begin=17, CMI=1
+Uplink, AMR AHS on HR subslot 0: fn_begin=21, CMI=0
+Uplink, AMR AHS on HR subslot 0: fn_begin=26, CMI=1
+Uplink, AMR AHS on HR subslot 0: fn_begin=30, CMI=0
+Uplink, AMR AHS on HR subslot 0: fn_begin=34, CMI=1
+Uplink, AMR AHS on HR subslot 0: fn_begin=39, CMI=0
+Uplink, AMR AHS on HR subslot 0: fn_begin=43, CMI=1
+Uplink, AMR AHS on HR subslot 0: fn_begin=47, CMI=0
+Uplink, AMR AHS on HR subslot 0: fn_begin=52, CMI=1
+Uplink, AMR AHS on HR subslot 0: fn_begin=56, CMI=0
+Uplink, AMR AHS on HR subslot 0: fn_begin=60, CMI=1
+Uplink, AMR AHS on HR subslot 0: fn_begin=65, CMI=0
+Uplink, AMR AHS on HR subslot 0: fn_begin=69, CMI=1
+Uplink, AMR AHS on HR subslot 0: fn_begin=73, CMI=0
+Uplink, AMR AHS on HR subslot 0: fn_begin=78, CMI=1
+Uplink, AMR AHS on HR subslot 0: fn_begin=82, CMI=0
+Uplink, AMR AHS on HR subslot 0: fn_begin=86, CMI=1
+Uplink, AMR AHS on HR subslot 0: fn_begin=91, CMI=0
+Uplink, AMR AHS on HR subslot 0: fn_begin=95, CMI=1
+Uplink, AMR AHS on HR subslot 0: fn_begin=99, CMI=0
+
+Downlink, AMR AHS on HR subslot 0: fn_begin=0, CMI=0
+Downlink, AMR AHS on HR subslot 0: fn_begin=4, CMI=1
+Downlink, AMR AHS on HR subslot 0: fn_begin=8, CMI=0
+Downlink, AMR AHS on HR subslot 0: fn_begin=13, CMI=1
+Downlink, AMR AHS on HR subslot 0: fn_begin=17, CMI=0
+Downlink, AMR AHS on HR subslot 0: fn_begin=21, CMI=1
+Downlink, AMR AHS on HR subslot 0: fn_begin=26, CMI=0
+Downlink, AMR AHS on HR subslot 0: fn_begin=30, CMI=1
+Downlink, AMR AHS on HR subslot 0: fn_begin=34, CMI=0
+Downlink, AMR AHS on HR subslot 0: fn_begin=39, CMI=1
+Downlink, AMR AHS on HR subslot 0: fn_begin=43, CMI=0
+Downlink, AMR AHS on HR subslot 0: fn_begin=47, CMI=1
+Downlink, AMR AHS on HR subslot 0: fn_begin=52, CMI=0
+Downlink, AMR AHS on HR subslot 0: fn_begin=56, CMI=1
+Downlink, AMR AHS on HR subslot 0: fn_begin=60, CMI=0
+Downlink, AMR AHS on HR subslot 0: fn_begin=65, CMI=1
+Downlink, AMR AHS on HR subslot 0: fn_begin=69, CMI=0
+Downlink, AMR AHS on HR subslot 0: fn_begin=73, CMI=1
+Downlink, AMR AHS on HR subslot 0: fn_begin=78, CMI=0
+Downlink, AMR AHS on HR subslot 0: fn_begin=82, CMI=1
+Downlink, AMR AHS on HR subslot 0: fn_begin=86, CMI=0
+Downlink, AMR AHS on HR subslot 0: fn_begin=91, CMI=1
+Downlink, AMR AHS on HR subslot 0: fn_begin=95, CMI=0
+Downlink, AMR AHS on HR subslot 0: fn_begin=99, CMI=1
+
+
+Uplink, AMR AHS on HR subslot 1: fn_begin=1, CMI=1
+Uplink, AMR AHS on HR subslot 1: fn_begin=5, CMI=0
+Uplink, AMR AHS on HR subslot 1: fn_begin=9, CMI=1
+Uplink, AMR AHS on HR subslot 1: fn_begin=14, CMI=0
+Uplink, AMR AHS on HR subslot 1: fn_begin=18, CMI=1
+Uplink, AMR AHS on HR subslot 1: fn_begin=22, CMI=0
+Uplink, AMR AHS on HR subslot 1: fn_begin=27, CMI=1
+Uplink, AMR AHS on HR subslot 1: fn_begin=31, CMI=0
+Uplink, AMR AHS on HR subslot 1: fn_begin=35, CMI=1
+Uplink, AMR AHS on HR subslot 1: fn_begin=40, CMI=0
+Uplink, AMR AHS on HR subslot 1: fn_begin=44, CMI=1
+Uplink, AMR AHS on HR subslot 1: fn_begin=48, CMI=0
+Uplink, AMR AHS on HR subslot 1: fn_begin=53, CMI=1
+Uplink, AMR AHS on HR subslot 1: fn_begin=57, CMI=0
+Uplink, AMR AHS on HR subslot 1: fn_begin=61, CMI=1
+Uplink, AMR AHS on HR subslot 1: fn_begin=66, CMI=0
+Uplink, AMR AHS on HR subslot 1: fn_begin=70, CMI=1
+Uplink, AMR AHS on HR subslot 1: fn_begin=74, CMI=0
+Uplink, AMR AHS on HR subslot 1: fn_begin=79, CMI=1
+Uplink, AMR AHS on HR subslot 1: fn_begin=83, CMI=0
+Uplink, AMR AHS on HR subslot 1: fn_begin=87, CMI=1
+Uplink, AMR AHS on HR subslot 1: fn_begin=92, CMI=0
+Uplink, AMR AHS on HR subslot 1: fn_begin=96, CMI=1
+Uplink, AMR AHS on HR subslot 1: fn_begin=100, CMI=0
+
+Downlink, AMR AHS on HR subslot 1: fn_begin=1, CMI=0
+Downlink, AMR AHS on HR subslot 1: fn_begin=5, CMI=1
+Downlink, AMR AHS on HR subslot 1: fn_begin=9, CMI=0
+Downlink, AMR AHS on HR subslot 1: fn_begin=14, CMI=1
+Downlink, AMR AHS on HR subslot 1: fn_begin=18, CMI=0
+Downlink, AMR AHS on HR subslot 1: fn_begin=22, CMI=1
+Downlink, AMR AHS on HR subslot 1: fn_begin=27, CMI=0
+Downlink, AMR AHS on HR subslot 1: fn_begin=31, CMI=1
+Downlink, AMR AHS on HR subslot 1: fn_begin=35, CMI=0
+Downlink, AMR AHS on HR subslot 1: fn_begin=40, CMI=1
+Downlink, AMR AHS on HR subslot 1: fn_begin=44, CMI=0
+Downlink, AMR AHS on HR subslot 1: fn_begin=48, CMI=1
+Downlink, AMR AHS on HR subslot 1: fn_begin=53, CMI=0
+Downlink, AMR AHS on HR subslot 1: fn_begin=57, CMI=1
+Downlink, AMR AHS on HR subslot 1: fn_begin=61, CMI=0
+Downlink, AMR AHS on HR subslot 1: fn_begin=66, CMI=1
+Downlink, AMR AHS on HR subslot 1: fn_begin=70, CMI=0
+Downlink, AMR AHS on HR subslot 1: fn_begin=74, CMI=1
+Downlink, AMR AHS on HR subslot 1: fn_begin=79, CMI=0
+Downlink, AMR AHS on HR subslot 1: fn_begin=83, CMI=1
+Downlink, AMR AHS on HR subslot 1: fn_begin=87, CMI=0
+Downlink, AMR AHS on HR subslot 1: fn_begin=92, CMI=1
+Downlink, AMR AHS on HR subslot 1: fn_begin=96, CMI=0
+Downlink, AMR AHS on HR subslot 1: fn_begin=100, CMI=1
+
+
+Uplink, AMR AFS: fn_begin=0, CMI=1
+Uplink, AMR AFS: fn_begin=4, CMI=0
+Uplink, AMR AFS: fn_begin=8, CMI=1
+Uplink, AMR AFS: fn_begin=13, CMI=0
+Uplink, AMR AFS: fn_begin=17, CMI=1
+Uplink, AMR AFS: fn_begin=21, CMI=0
+Uplink, AMR AFS: fn_begin=26, CMI=1
+Uplink, AMR AFS: fn_begin=30, CMI=0
+Uplink, AMR AFS: fn_begin=34, CMI=1
+Uplink, AMR AFS: fn_begin=39, CMI=0
+Uplink, AMR AFS: fn_begin=43, CMI=1
+Uplink, AMR AFS: fn_begin=47, CMI=0
+Uplink, AMR AFS: fn_begin=52, CMI=1
+Uplink, AMR AFS: fn_begin=56, CMI=0
+Uplink, AMR AFS: fn_begin=60, CMI=1
+Uplink, AMR AFS: fn_begin=65, CMI=0
+Uplink, AMR AFS: fn_begin=69, CMI=1
+Uplink, AMR AFS: fn_begin=73, CMI=0
+Uplink, AMR AFS: fn_begin=78, CMI=1
+Uplink, AMR AFS: fn_begin=82, CMI=0
+Uplink, AMR AFS: fn_begin=86, CMI=1
+Uplink, AMR AFS: fn_begin=91, CMI=0
+Uplink, AMR AFS: fn_begin=95, CMI=1
+Uplink, AMR AFS: fn_begin=99, CMI=0
+
+Downlink, AMR AFS: fn_begin=0, CMI=0
+Downlink, AMR AFS: fn_begin=4, CMI=1
+Downlink, AMR AFS: fn_begin=8, CMI=0
+Downlink, AMR AFS: fn_begin=13, CMI=1
+Downlink, AMR AFS: fn_begin=17, CMI=0
+Downlink, AMR AFS: fn_begin=21, CMI=1
+Downlink, AMR AFS: fn_begin=26, CMI=0
+Downlink, AMR AFS: fn_begin=30, CMI=1
+Downlink, AMR AFS: fn_begin=34, CMI=0
+Downlink, AMR AFS: fn_begin=39, CMI=1
+Downlink, AMR AFS: fn_begin=43, CMI=0
+Downlink, AMR AFS: fn_begin=47, CMI=1
+Downlink, AMR AFS: fn_begin=52, CMI=0
+Downlink, AMR AFS: fn_begin=56, CMI=1
+Downlink, AMR AFS: fn_begin=60, CMI=0
+Downlink, AMR AFS: fn_begin=65, CMI=1
+Downlink, AMR AFS: fn_begin=69, CMI=0
+Downlink, AMR AFS: fn_begin=73, CMI=1
+Downlink, AMR AFS: fn_begin=78, CMI=0
+Downlink, AMR AFS: fn_begin=82, CMI=1
+Downlink, AMR AFS: fn_begin=86, CMI=0
+Downlink, AMR AFS: fn_begin=91, CMI=1
+Downlink, AMR AFS: fn_begin=95, CMI=0
+Downlink, AMR AFS: fn_begin=99, CMI=1