Introduce BTS feature BTS_FEAT_MS_PWR_CTRL_DSP

It indicates whether BTS model supports managing an MS Power Control
Loop over HW/DSP instead of using the software based osmocom algorithm
present in osmo-bts.
osmo-bts-trx own loop implementation is considered to be a "DSP/HW" one
since it acts on lower layers and interferes with osmocom algorithm
since it controls the same end variable "lchan->ms_power_ctrl.current",
this way we make sure both aren't enabled at the same time.
Old behavior in kept: if common upper-layer algo is not enabled
explicitly in VTY (ms-power-control osmo) and bts-trx specific lower
layer algo is neither enabled (osmotrx ms-power-loop <xyz>), then no
power control is done at all.

Related: OS#1851
Change-Id: I49706926b1e962b18791174627bc3cc0cd0cd9d5

8 files changed, 22 insertions, 4 deletions

diff --git a/src/common/bts.c b/src/common/bts.c
index 3809eb3e..da411761 100644
--- a/src/common/bts.c
+++ b/src/common/bts.c
@@ -256,6 +256,10 @@ int bts_trx_init(struct gsm_bts_trx *trx)
 	tpp->ramp.step_size_mdB = to_mdB(2);
 	tpp->ramp.step_interval_sec = 1;
 
+	/* IF BTS model doesn't DSP/HW support MS Power Control Loop, enable osmo algo by default: */
+	if (!gsm_bts_has_feature(trx->bts, BTS_FEAT_MS_PWR_CTRL_DSP))
+		trx->ms_pwr_ctl_soft = true;
+
 	rc = bts_model_trx_init(trx);
 	if (rc < 0) {
 		llist_del(&trx->list);
diff --git a/src/common/gsm_data_shared.c b/src/common/gsm_data_shared.c
index 80acabcb..b31d458b 100644
--- a/src/common/gsm_data_shared.c
+++ b/src/common/gsm_data_shared.c
@@ -108,6 +108,7 @@ const struct value_string gsm_bts_features_descs[] = {
 	{ BTS_FEAT_SPEECH_F_AMR,	"Fullrate speech AMR" },
 	{ BTS_FEAT_SPEECH_H_AMR,	"Halfrate speech AMR" },
 	{ BTS_FEAT_ETWS_PN,		"ETWS Primary Notification on PCH" },
+	{ BTS_FEAT_MS_PWR_CTRL_DSP,	"DSP/HW based MS Power Control Loop" },
 	{ 0, NULL }
 };
 
diff --git a/src/common/vty.c b/src/common/vty.c
index 514d1202..2558ba85 100644
--- a/src/common/vty.c
+++ b/src/common/vty.c
@@ -789,8 +789,14 @@ DEFUN(cfg_trx_ms_power_control, cfg_trx_ms_power_control_cmd,
 	"Handled by DSP\n" "Handled by OsmoBTS\n")
 {
 	struct gsm_bts_trx *trx = vty->index;
+	bool soft = !strcmp(argv[0], "osmo");
 
-	trx->ms_pwr_ctl_soft = !strcmp(argv[0], "osmo");
+	if (!soft && !gsm_bts_has_feature(trx->bts, BTS_FEAT_MS_PWR_CTRL_DSP)) {
+		vty_out(vty, "This BTS model has no DSP/HW MS Power Control support%s", VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	trx->ms_pwr_ctl_soft = soft;
 	return CMD_SUCCESS;
 }
 
diff --git a/src/osmo-bts-litecell15/main.c b/src/osmo-bts-litecell15/main.c
index b0d725b8..6f3fc006 100644
--- a/src/osmo-bts-litecell15/main.c
+++ b/src/osmo-bts-litecell15/main.c
@@ -112,6 +112,7 @@ int bts_model_init(struct gsm_bts *bts)
 	gsm_bts_set_feature(bts, BTS_FEAT_SPEECH_F_EFR);
 	gsm_bts_set_feature(bts, BTS_FEAT_SPEECH_F_AMR);
 	gsm_bts_set_feature(bts, BTS_FEAT_SPEECH_H_AMR);
+	gsm_bts_set_feature(bts, BTS_FEAT_MS_PWR_CTRL_DSP);
 
 	bts_model_vty_init(bts);
 
diff --git a/src/osmo-bts-oc2g/main.c b/src/osmo-bts-oc2g/main.c
index cbf5c420..f9bb0cb1 100644
--- a/src/osmo-bts-oc2g/main.c
+++ b/src/osmo-bts-oc2g/main.c
@@ -120,6 +120,7 @@ int bts_model_init(struct gsm_bts *bts)
 	gsm_bts_set_feature(bts, BTS_FEAT_SPEECH_F_EFR);
 	gsm_bts_set_feature(bts, BTS_FEAT_SPEECH_F_AMR);
 	gsm_bts_set_feature(bts, BTS_FEAT_SPEECH_H_AMR);
+	gsm_bts_set_feature(bts, BTS_FEAT_MS_PWR_CTRL_DSP);
 
 	bts_model_vty_init(bts);
 
diff --git a/src/osmo-bts-sysmo/main.c b/src/osmo-bts-sysmo/main.c
index ad7118ae..bb2c4363 100644
--- a/src/osmo-bts-sysmo/main.c
+++ b/src/osmo-bts-sysmo/main.c
@@ -86,6 +86,7 @@ int bts_model_init(struct gsm_bts *bts)
 	gsm_bts_set_feature(bts, BTS_FEAT_SPEECH_F_EFR);
 	gsm_bts_set_feature(bts, BTS_FEAT_SPEECH_F_AMR);
 	gsm_bts_set_feature(bts, BTS_FEAT_SPEECH_H_AMR);
+	gsm_bts_set_feature(bts, BTS_FEAT_MS_PWR_CTRL_DSP);
 
 	bts_model_vty_init(bts);
 
diff --git a/src/osmo-bts-trx/loops.c b/src/osmo-bts-trx/loops.c
index 1f54feec..e73d842c 100644
--- a/src/osmo-bts-trx/loops.c
+++ b/src/osmo-bts-trx/loops.c
@@ -237,8 +237,9 @@ void trx_loop_sacch_input(struct l1sched_trx *l1t, uint8_t chan_nr,
 					.lchan[l1sap_chan2ss(chan_nr)];
 	struct phy_instance *pinst = trx_phy_instance(l1t->trx);
 
-	/* if MS power control loop is enabled, handle it */
-	if (pinst->phy_link->u.osmotrx.trx_ms_power_loop)
+	/* if common upper layer MS power control loop is disabled
+	   and lower layer MS power control loop is enabled, handle it */
+	if (!l1t->trx->ms_pwr_ctl_soft && pinst->phy_link->u.osmotrx.trx_ms_power_loop)
 		ms_power_val(lchan, chan_state, rssi);
 
 	/* if TA loop is enabled, handle it */
@@ -257,7 +258,9 @@ void trx_loop_sacch_clock(struct l1sched_trx *l1t, uint8_t chan_nr,
 	if (lchan->ms_power_ctrl.fixed)
 	        return;
 
-	if (pinst->phy_link->u.osmotrx.trx_ms_power_loop)
+	/* if common upper layer MS power control loop is disabled
+	   and lower layer MS power control loop is enabled, handle it */
+	if (!l1t->trx->ms_pwr_ctl_soft && pinst->phy_link->u.osmotrx.trx_ms_power_loop)
 		ms_power_clock(lchan, chan_state);
 
 	/* count the number of SACCH clocks */
diff --git a/src/osmo-bts-trx/main.c b/src/osmo-bts-trx/main.c
index cf40ea3f..9a29b3b2 100644
--- a/src/osmo-bts-trx/main.c
+++ b/src/osmo-bts-trx/main.c
@@ -116,6 +116,7 @@ int bts_model_init(struct gsm_bts *bts)
 	gsm_bts_set_feature(bts, BTS_FEAT_SPEECH_F_AMR);
 	gsm_bts_set_feature(bts, BTS_FEAT_SPEECH_H_AMR);
 	gsm_bts_set_feature(bts, BTS_FEAT_CBCH);
+	gsm_bts_set_feature(bts, BTS_FEAT_MS_PWR_CTRL_DSP);
 
 	bts_model_vty_init(bts);