rsl: Assign recv pwr to lchan's max ms power

Otherwise older ms_power value will be kept and used as a maximum.

From TS 08.58 sec 4.8 "MS power control":
"""
If power control is supported by BTS and it is to be used,
this is indicated by optional parameters in the MS POWER CONTROL
message (or the CHANNEL ACTIVATION message). Based on the
measurements performed on the uplink, TRX then attempts to keep
the power control parameters within the limits set by the
MS POWER CONTROL message (or by the CHANNEL ACTIVATION message).
"""

Change-Id: I0583eef477c33279ee5bfcda80141f365413a276

1 files changed, 22 insertions, 2 deletions

diff --git a/src/common/rsl.c b/src/common/rsl.c
index de51e6f4..e460693c 100644
--- a/src/common/rsl.c
+++ b/src/common/rsl.c
@@ -26,6 +26,7 @@
 #include <errno.h>
 #include <netdb.h>
 #include <stdbool.h>
+#include <inttypes.h>
 #include <sys/types.h>
 #include <arpa/inet.h>
 
@@ -1623,8 +1624,10 @@ static int rsl_rx_ms_pwr_ctrl(struct msgb *msg)
 {
 	struct abis_rsl_dchan_hdr *dch = msgb_l2(msg);
 	struct gsm_lchan *lchan = msg->lchan;
+	struct gsm_bts *bts = lchan->ts->trx->bts;
 	struct tlv_parsed tp;
 	uint8_t pwr;
+	int max_pwr, curr_pwr;
 
 	rsl_tlv_parse(&tp, msgb_l3(msg), msgb_l3len(msg));
 
@@ -1633,9 +1636,9 @@ static int rsl_rx_ms_pwr_ctrl(struct msgb *msg)
 		return rsl_tx_error_report(msg->trx, RSL_ERR_MAND_IE_ERROR, &dch->chan_nr, NULL, msg);
 
 	pwr = *TLVP_VAL(&tp, RSL_IE_MS_POWER) & 0x1F;
-	lchan->ms_power_ctrl.current = pwr;
+	lchan->ms_power = pwr;
 
-	LOGPLCHAN(lchan, DRSL, LOGL_NOTICE, "Rx MS POWER CONTROL %d\n", lchan->ms_power_ctrl.current);
+	LOGPLCHAN(lchan, DRSL, LOGL_INFO, "Rx MS POWER CONTROL %d\n", lchan->ms_power_ctrl.current);
 
 	/* 9.3.31 MS Power Parameters (O) */
 	if (TLVP_PRESENT(&tp, RSL_IE_MS_POWER_PARAM))
@@ -1647,6 +1650,23 @@ static int rsl_rx_ms_pwr_ctrl(struct msgb *msg)
 		lchan->ms_power_ctrl.fixed = 1;
 	}
 
+	/* Only set current to lchan->ms_power if actual value of current
+	   in dBm > value in dBm from lchan->ms_power, or if fixed=1. */
+	if (lchan->ms_power_ctrl.fixed) {
+		lchan->ms_power_ctrl.current = lchan->ms_power;
+	} else {
+		max_pwr = ms_pwr_dbm(bts->band, lchan->ms_power);
+		curr_pwr = ms_pwr_dbm(bts->band, lchan->ms_power_ctrl.current);
+		if (max_pwr < 0 || curr_pwr < 0) {
+			LOGPLCHAN(lchan, DRSL, LOGL_ERROR,
+				  "Unable to calculate power levels to dBm: %" PRIu8 " -> %d, %" PRIu8 " -> %d\n",
+				  lchan->ms_power, max_pwr,
+				  lchan->ms_power_ctrl.current, curr_pwr);
+		} else if (curr_pwr > max_pwr) {
+			lchan->ms_power_ctrl.current = lchan->ms_power;
+		}
+	}
+
 	bts_model_adjst_ms_pwr(lchan);
 
 	return 0;