power/sysmobts: Add a manual ms power level control

Currently the DSP is instructed to achieve a given uplink
power target but there are circumstances (e.g. EMV testing)
where we need more control over it. The "manual/software/osmo"
power control can only be implemented per TRX and not per
lchan. Add a very very basic control that checks the MS Power
used by the phone, the actual receive level and then adjust
the power.

The code doesn't take the history into account, if the phone
can not reach the requested power level the code will be stuck
(e.g. no timeout based on multiframes). It has a mode for a
fixed power control but no way to set it yet.

The change of the mode requires a restart of the software.

2 files changed, 58 insertions, 0 deletions

diff --git a/tests/sysmobts/sysmobts_test.c b/tests/sysmobts/sysmobts_test.c
index acbc09c9..7db12485 100644
--- a/tests/sysmobts/sysmobts_test.c
+++ b/tests/sysmobts/sysmobts_test.c
@@ -179,11 +179,68 @@ static void test_sysmobts_cipher(void)
 	OSMO_ASSERT(lchan.ciph_state == LCHAN_CIPH_TXRX_REQ);
 }
 
+static void test_sysmobts_loop(void)
+{
+	struct gsm_bts bts;
+	struct gsm_bts_trx trx;
+	struct gsm_bts_trx_ts ts;
+	struct gsm_lchan *lchan;
+	int ret;
+
+	memset(&bts, 0, sizeof(bts));
+	memset(&trx, 0, sizeof(trx));
+	memset(&ts, 0, sizeof(ts));
+
+	lchan = &ts.lchan[0];
+	lchan->ts = &ts;
+	ts.trx = &trx;
+	trx.bts = &bts;
+	bts.band = GSM_BAND_1800;
+	trx.ms_power_control = 1;
+
+	printf("Testing sysmobts power control\n");
+
+	/* Simply clamping */
+	lchan->state = LCHAN_S_NONE;
+	lchan->ms_power_ctrl.current = ms_pwr_ctl_lvl(GSM_BAND_1800, 0);
+	OSMO_ASSERT(lchan->ms_power_ctrl.current == 15);
+	ret = l1if_ms_pwr_ctrl(lchan, -75, lchan->ms_power_ctrl.current, -60);
+	OSMO_ASSERT(ret == 0);
+	OSMO_ASSERT(lchan->ms_power_ctrl.current == 15);
+
+
+	/*
+	 * Now 15 dB too little and we should power it up. Could be a
+	 * power level of 7 or 8 for 15 dBm
+	 */
+	ret = l1if_ms_pwr_ctrl(lchan, -75, lchan->ms_power_ctrl.current, -90);
+	OSMO_ASSERT(ret == 1);
+	OSMO_ASSERT(lchan->ms_power_ctrl.current == 7);
+
+	/* It should be clamped to level 0 and 30 dBm */
+	ret = l1if_ms_pwr_ctrl(lchan, -75, lchan->ms_power_ctrl.current, -100);
+	OSMO_ASSERT(ret == 1);
+	OSMO_ASSERT(lchan->ms_power_ctrl.current == 0);
+
+	/* Fix it and jump down */
+	lchan->ms_power_ctrl.fixed = 1;
+	ret = l1if_ms_pwr_ctrl(lchan, -75, lchan->ms_power_ctrl.current, -60);
+	OSMO_ASSERT(ret == 0);
+	OSMO_ASSERT(lchan->ms_power_ctrl.current == 0);
+
+	/* And leave it again */
+	lchan->ms_power_ctrl.fixed = 0;
+	ret = l1if_ms_pwr_ctrl(lchan, -75, lchan->ms_power_ctrl.current, -40);
+	OSMO_ASSERT(ret == 1);
+	OSMO_ASSERT(lchan->ms_power_ctrl.current == 15);
+}
+
 int main(int argc, char **argv)
 {
 	printf("Testing sysmobts routines\n");
 	test_sysmobts_auto_band();
 	test_sysmobts_cipher();
+	test_sysmobts_loop();
 	return 0;
 }
 
diff --git a/tests/sysmobts/sysmobts_test.ok b/tests/sysmobts/sysmobts_test.ok
index 1f534172..07d79fd3 100644
--- a/tests/sysmobts/sysmobts_test.ok
+++ b/tests/sysmobts/sysmobts_test.ok
@@ -17,3 +17,4 @@ Checking PCS to PCS
 PCS to PCS band(1) arfcn(512) want(3) got(3)
 PCS to PCS band(8) arfcn(128) want(0) got(0)
 PCS to PCS band(2) arfcn(438) want(-1) got(-1)
+Testing sysmobts power control