large refactoring: use FSMs for lchans; add inter-BSC HO

Add FSMs:

- timeslot_fsm: handle dynamic timeslots and OML+RSL availability.
- lchan_fsm: handle an individual lchan activation, RTP stream and release,
  signal the appropriate calling FSMs on success, failure, release.
- mgw_endpoint_fsm: handle one entire endpoint with several CI.
- assignment_fsm: BSSMAP Assignment Request.
- handover_fsm: all of intra, inter-MO and inter-MT handover.

Above FSMs absorb large parts of the gscon FSM. The gscon FSM was surpassing
the maximum amount events (32), and it is more logical to treat assignment,
handover and MGW procedures in separate FSMs.

- Add logging macros for each FSM type:
  - LOG_TS()
  - LOG_LCHAN()
  - LOG_MGWEP(), LOG_CI()
  - LOG_ASSIGNMENT()
  - LOG_HO()
  These log with the osmo_fsm_inst where present.
  New style decision: logging without a final newline char is awkward,
  especially for gsmtap logging and when other logs interleave LOGPC() calls;
  we have various cases where the final \n goes missing, and also this invokes
  the log category checking N times instead of once.
  So I decided to make these macros *always* append a newline, but only if
  there is no final newline yet. I hope that the compiler optimizes the
  strlen() of the constant format strings away. Thus I can log with or without
  typing "\n" and always get an \n termination anyway.

General:

- replace osmo_timers, state enums and program-wide osmo_signal_dispatch()
  with dedicated FSM timeouts, states and events.

- introduce a common way to handle Tnnn timers: gsm_timers.h/.c: struct T_def.
  These can be used (with some macro magic) to define a state's timeout once,
  and not make mistakes for each osmo_fsm_inst_state_chg().

Details:

bsc_subscr_conn_fsm.c:

- move most states of this FSM to lchan_fsm, assignment_fsm, handover_fsm and
  mgw_endpoint_fsm.

- There is exactly one state for an ongoing Assignment, with all details
  handled in conn->assignment.fi. The state relies on the assignment_fsm's
  timeout.

- There is one state for an ongoing Handover; except for an incoming Handover
  from a remote BSS, the gscon remains in ST_INIT until the new lchan and conn
  are both established.

- move bssmap_add_lcls_status() to osmo_bsc_lcls.c

abis_rsl.c:

- move all dynamic timeslot logic away into timeslot_fsm. Only keep plain send/receive functions in
  abis_rsl.c

- reduce some rsl functions to merely send a message, rename to "_tx_".
  - rsl_ipacc_mdcx(): add '_tx_' in the name; move parts that change the lchan state out into the
    lchan_fsm, the lchan->abis_ip.* are now set there prior to invoking this function.

- move all timers and error/release handling away into various FSMs.

- tweak ipa_smod_s_for_lchan() and ipa_rtp_pt_for_lchan() to not require an
  lchan passed, but just mode,type that they require. Rename to
  ipacc_speech_mode*() and ipacc_payload_type().

- add rsl_forward_layer3_info, used for inter-BSC HO MO, to just send the RR
  message received during BSSMAP Handover Command.

- move various logging to LOG_LCHAN() in order to log with the lchan FSM instance.
  One drawback is that the lchan FSM is limited to one logging category, i.e. this moves some logging
  from DRR to DRSL. It might actually make sense to combine those categories.

- lose LOGP...LOGPC logging cascades: they are bad for gsmtap logging and for performance.

- handle_classmark_chg(): change logging, move cm2 len check out of the cm3 condition (I hope that's
  correct).

- gsm48_send_ho_cmd(): split off gsm48_make_ho_cmd() which doesn't send right away, so that during
  inter-bsc HO we can make an RR Handover Command to send via the MSC to the remote BSS.

assignment_fsm.c:

- the Chan Mode Modify in case of re-using the same lchan is not implemented
  yet, because this was also missing in the previous implementation (OS#3357).

osmo_bsc_api.c:

- simplify bsc_mr_config() and move to lchan_fsm.c, the only caller; rename to
  lchan_mr_config(). (bsc_mr_config() used to copy the values to mr_bts_lv
  twice, once by member assignment and then again with a memcpy.)

- During handover, we used to copy the MR config from the old lchan. Since we
  may handover between FR and HR, rather set the MR Config anew every time, so
  that FR rates are always available on FR lchans, and never on HR lchans.

Depends: I03ee7ce840ecfa0b6a33358e7385528aabd4873f (libosmocore),
         I1f2918418c38918c5ac70acaa51a47adfca12b5e (libosmocore)
Change-Id: I82e3f918295daa83274a4cf803f046979f284366

1 files changed, 7 insertions, 575 deletions

diff --git a/src/osmo-bsc/chan_alloc.c b/src/osmo-bsc/chan_alloc.c
index c73ecb74b..9c434145f 100644
--- a/src/osmo-bsc/chan_alloc.c
+++ b/src/osmo-bsc/chan_alloc.c
@@ -31,576 +31,12 @@
 #include <osmocom/bsc/abis_rsl.h>
 #include <osmocom/bsc/debug.h>
 #include <osmocom/bsc/signal.h>
+#include <osmocom/bsc/timeslot_fsm.h>
+#include <osmocom/bsc/lchan_fsm.h>
 #include <osmocom/bsc/gsm_04_08_rr.h>
 
 #include <osmocom/core/talloc.h>
 
-bool ts_is_usable(const struct gsm_bts_trx_ts *ts)
-{
-	if (!trx_is_usable(ts->trx)) {
-		LOGP(DRLL, LOGL_DEBUG, "%s not usable\n", gsm_trx_name(ts->trx));
-		return false;
-	}
-
-	/* If a TCH/F_PDCH TS is busy changing, it is already taken or not
-	 * yet available. */
-	if (ts->pchan == GSM_PCHAN_TCH_F_PDCH) {
-		if (ts->flags & TS_F_PDCH_PENDING_MASK) {
-			LOGP(DRLL, LOGL_DEBUG, "%s in switchover, not available\n",
-			     gsm_ts_and_pchan_name(ts));
-			return false;
-		}
-	}
-
-	/* If a dynamic channel is busy changing, it is already taken or not
-	 * yet available. */
-	if (ts->pchan == GSM_PCHAN_TCH_F_TCH_H_PDCH) {
-		if (ts->dyn.pchan_is != ts->dyn.pchan_want) {
-			LOGP(DRLL, LOGL_DEBUG, "%s in switchover, not available\n",
-			     gsm_ts_and_pchan_name(ts));
-			return false;
-		}
-	}
-
-	return true;
-}
-
-static int trx_count_free_ts(struct gsm_bts_trx *trx, enum gsm_phys_chan_config pchan)
-{
-	struct gsm_bts_trx_ts *ts;
-	int j, ss;
-	int count = 0;
-
-	if (!trx_is_usable(trx))
-		return 0;
-
-	for (j = 0; j < ARRAY_SIZE(trx->ts); j++) {
-		enum gsm_phys_chan_config ts_pchan_is;
-		ts = &trx->ts[j];
-		if (!ts_is_usable(ts))
-			continue;
-
-		ts_pchan_is = ts_pchan(ts);
-
-		if (ts_pchan_is == GSM_PCHAN_PDCH) {
-			/* Dynamic timeslots in PDCH mode will become TCH if needed. */
-			switch (ts->pchan) {
-			case GSM_PCHAN_TCH_F_PDCH:
-				if (pchan == GSM_PCHAN_TCH_F)
-					count++;
-				continue;
-
-			case GSM_PCHAN_TCH_F_TCH_H_PDCH:
-				if (pchan == GSM_PCHAN_TCH_F)
-					count++;
-				else if (pchan == GSM_PCHAN_TCH_H)
-					count += 2;
-				continue;
-
-			default:
-				/* Not dynamic, not applicable. */
-				continue;
-			}
-		}
-
-		if (ts_pchan_is != pchan)
-			continue;
-		/* check if all sub-slots are allocated yet */
-		for (ss = 0; ss < ts_subslots(ts); ss++) {
-			struct gsm_lchan *lc = &ts->lchan[ss];
-			if (lc->type == GSM_LCHAN_NONE &&
-			    lc->state == LCHAN_S_NONE)
-				count++;
-		}
-	}
-
-	return count;
-}
-
-/* Count number of free TS of given pchan type */
-int bts_count_free_ts(struct gsm_bts *bts, enum gsm_phys_chan_config pchan)
-{
-	struct gsm_bts_trx *trx;
-	int count = 0;
-
-	llist_for_each_entry(trx, &bts->trx_list, list)
-		count += trx_count_free_ts(trx, pchan);
-
-	return count;
-}
-
-static bool ts_usable_as_pchan(struct gsm_bts_trx_ts *ts,
-			       enum gsm_phys_chan_config as_pchan)
-{
-	switch (ts->pchan) {
-	case GSM_PCHAN_TCH_F_PDCH:
-		if (ts->flags & TS_F_PDCH_PENDING_MASK) {
-			/* currently being switched over. Not usable. */
-			return false;
-		}
-		switch (as_pchan) {
-		case GSM_PCHAN_TCH_F:
-		case GSM_PCHAN_PDCH:
-			/* continue to check below. */
-			break;
-		default:
-			return false;
-		}
-		break;
-
-	case GSM_PCHAN_TCH_F_TCH_H_PDCH:
-		if (ts->dyn.pchan_is != ts->dyn.pchan_want) {
-			/* currently being switched over. Not usable. */
-			return false;
-		}
-		switch (as_pchan) {
-		case GSM_PCHAN_TCH_F:
-		case GSM_PCHAN_TCH_H:
-		case GSM_PCHAN_PDCH:
-			/* continue to check below. */
-			break;
-		default:
-			return false;
-		}
-		break;
-
-	default:
-		/* static timeslots never switch. */
-		return ts->pchan == as_pchan;
-	}
-
-	/* Dynamic timeslots -- Checks depending on the current actual pchan mode: */
-	switch (ts_pchan(ts)) {
-	case GSM_PCHAN_NONE:
-		/* Not initialized, possibly because GPRS was disabled. We may switch. */
-		return true;
-
-	case GSM_PCHAN_PDCH:
-		/* This slot is in PDCH mode and available to switch pchan mode. But check for
-		 * error states: */
-		if (ts->lchan->state != LCHAN_S_NONE && ts->lchan->state != LCHAN_S_ACTIVE)
-			return false;
-		return true;
-
-	case GSM_PCHAN_TCH_F:
-	case GSM_PCHAN_TCH_H:
-		/* No need to switch at all? */
-		if (ts_pchan(ts) == as_pchan)
-			return true;
-
-		/* If any lchan is in use, we can't change the pchan kind */
-		{
-			int ss;
-			int subslots = ts_subslots(ts);
-			for (ss = 0; ss < subslots; ss++) {
-				struct gsm_lchan *lc = &ts->lchan[ss];
-				if (lc->type != GSM_LCHAN_NONE || lc->state != LCHAN_S_NONE)
-					return false;
-			}
-		}
-		return true;
-
-	default:
-		/* Not implemented. */
-		return false;
-	}
-}
-
-static struct gsm_lchan *
-_lc_find_trx(struct gsm_bts_trx *trx, enum gsm_phys_chan_config pchan,
-	     enum gsm_phys_chan_config as_pchan)
-{
-	struct gsm_bts_trx_ts *ts;
-	int j, start, stop, dir, ss;
-	int check_subslots;
-
-#define LOGPLCHANALLOC(fmt, args...) \
-		LOGP(DRLL, LOGL_DEBUG, "looking for lchan %s as %s: " fmt, \
-		     gsm_pchan_name(pchan), gsm_pchan_name(as_pchan), ## args)
-
-	if (!trx_is_usable(trx)) {
-		LOGPLCHANALLOC("%s trx not usable\n", gsm_trx_name(trx));
-		return NULL;
-	}
-
-	if (trx->bts->chan_alloc_reverse) {
-		/* check TS 7..0 */
-		start = 7;
-		stop = -1;
-		dir = -1;
-	} else {
-		/* check TS 0..7 */
-		start = 0;
-		stop = 8;
-		dir = 1;
-	}
-
-	for (j = start; j != stop; j += dir) {
-		ts = &trx->ts[j];
-		if (!ts_is_usable(ts))
-			continue;
-		/* The caller first selects what kind of TS to search in, e.g. looking for exact
-		 * GSM_PCHAN_TCH_F, or maybe among dynamic GSM_PCHAN_TCH_F_TCH_H_PDCH... */
-		if (ts->pchan != pchan) {
-			LOGPLCHANALLOC("%s is != %s\n", gsm_ts_and_pchan_name(ts),
-				       gsm_pchan_name(pchan));
-			continue;
-		}
-		/* Next, is this timeslot in or can it be switched to the pchan we want to use it for? */
-		if (!ts_usable_as_pchan(ts, as_pchan)) {
-			LOGPLCHANALLOC("%s is not usable as %s\n", gsm_ts_and_pchan_name(ts),
-				       gsm_pchan_name(as_pchan));
-			continue;
-		}
-		/* If we need to switch it, after above check we are also allowed to switch it, and we
-		 * will always use the first lchan after the switch. Return that lchan and rely on the
-		 * caller to perform the pchan switchover. */
-		if (ts_pchan(ts) != as_pchan) {
-			LOGPLCHANALLOC("%s is a match, will switch to %s\n", gsm_ts_and_pchan_name(ts),
-				       gsm_pchan_name(as_pchan));
-			return ts->lchan;
-		}
-
-		/* TS is in desired pchan mode. Go ahead and check for an available lchan. */
-		check_subslots = ts_subslots(ts);
-		for (ss = 0; ss < check_subslots; ss++) {
-			struct gsm_lchan *lc = &ts->lchan[ss];
-			if (lc->type == GSM_LCHAN_NONE &&
-			    lc->state == LCHAN_S_NONE) {
-				LOGPLCHANALLOC("%s ss=%d is available\n", gsm_ts_and_pchan_name(ts),
-					       lc->nr);
-				return lc;
-			}
-			LOGPLCHANALLOC("%s ss=%d in type=%s,state=%s not suitable\n",
-				       gsm_ts_and_pchan_name(ts), lc->nr, gsm_lchant_name(lc->type),
-				       gsm_lchans_name(lc->state));
-		}
-	}
-
-	return NULL;
-#undef LOGPLCHANALLOC
-}
-
-static struct gsm_lchan *
-_lc_dyn_find_bts(struct gsm_bts *bts, enum gsm_phys_chan_config pchan,
-		 enum gsm_phys_chan_config dyn_as_pchan)
-{
-	struct gsm_bts_trx *trx;
-	struct gsm_lchan *lc;
-
-	if (bts->chan_alloc_reverse) {
-		llist_for_each_entry_reverse(trx, &bts->trx_list, list) {
-			lc = _lc_find_trx(trx, pchan, dyn_as_pchan);
-			if (lc)
-				return lc;
-		}
-	} else {
-		llist_for_each_entry(trx, &bts->trx_list, list) {
-			lc = _lc_find_trx(trx, pchan, dyn_as_pchan);
-			if (lc)
-				return lc;
-		}
-	}
-
-	return NULL;
-}
-
-static struct gsm_lchan *
-_lc_find_bts(struct gsm_bts *bts, enum gsm_phys_chan_config pchan)
-{
-	return _lc_dyn_find_bts(bts, pchan, pchan);
-}
-
-/* Allocate a logical channel.
- *
- * Dynamic channel types: we always prefer a dedicated TS, and only pick +
- * switch a dynamic TS if no pure TS of the requested PCHAN is available.
- *
- * TCH_F/PDCH: if we pick a PDCH ACT style dynamic TS as TCH/F channel, PDCH
- * will be disabled in rsl_chan_activate_lchan(); there is no need to check
- * whether PDCH mode is currently active, here.
- */
-struct gsm_lchan *lchan_alloc(struct gsm_bts *bts, enum gsm_chan_t type,
-			      int allow_bigger)
-{
-	struct gsm_lchan *lchan = NULL;
-	enum gsm_phys_chan_config first, first_cbch, second, second_cbch;
-
-	LOGP(DRLL, LOGL_DEBUG, "(bts=%d) lchan_alloc(%s)\n", bts->nr, gsm_lchant_name(type));
-
-	switch (type) {
-	case GSM_LCHAN_SDCCH:
-		if (bts->chan_alloc_reverse) {
-			first = GSM_PCHAN_SDCCH8_SACCH8C;
-			first_cbch = GSM_PCHAN_SDCCH8_SACCH8C_CBCH;
-			second = GSM_PCHAN_CCCH_SDCCH4;
-			second_cbch = GSM_PCHAN_CCCH_SDCCH4_CBCH;
-		} else {
-			first = GSM_PCHAN_CCCH_SDCCH4;
-			first_cbch = GSM_PCHAN_CCCH_SDCCH4_CBCH;
-			second = GSM_PCHAN_SDCCH8_SACCH8C;
-			second_cbch = GSM_PCHAN_SDCCH8_SACCH8C_CBCH;
-		}
-
-		lchan = _lc_find_bts(bts, first);
-		if (lchan == NULL)
-			lchan = _lc_find_bts(bts, first_cbch);
-		if (lchan == NULL)
-			lchan = _lc_find_bts(bts, second);
-		if (lchan == NULL)
-			lchan = _lc_find_bts(bts, second_cbch);
-
-		/* allow to assign bigger channels */
-		if (allow_bigger) {
-			if (lchan == NULL) {
-				lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_H);
-				if (lchan)
-					type = GSM_LCHAN_TCH_H;
-			}
-
-			if (lchan == NULL) {
-				lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_F);
-				if (lchan)
-					type = GSM_LCHAN_TCH_F;
-			}
-
-			/* try dynamic TCH/F_PDCH */
-			if (lchan == NULL) {
-				lchan = _lc_dyn_find_bts(bts, GSM_PCHAN_TCH_F_PDCH,
-							 GSM_PCHAN_TCH_F);
-				/* TCH/F_PDCH will be used as TCH/F */
-				if (lchan)
-					type = GSM_LCHAN_TCH_F;
-			}
-
-			/* try fully dynamic TCH/F_TCH/H_PDCH */
-			if (lchan == NULL) {
-				lchan = _lc_dyn_find_bts(bts, GSM_PCHAN_TCH_F_TCH_H_PDCH,
-							 GSM_PCHAN_TCH_H);
-				if (lchan)
-					type = GSM_LCHAN_TCH_H;
-			}
-			/*
-			 * No need to check fully dynamic channels for TCH/F:
-			 * if no TCH/H was available, neither will be TCH/F.
-			 */
-		}
-		break;
-	case GSM_LCHAN_TCH_F:
-		lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_F);
-		/* If we don't have TCH/F available, fall-back to TCH/H */
-		if (!lchan) {
-			lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_H);
-			if (lchan)
-				type = GSM_LCHAN_TCH_H;
-		}
-		/* If we don't have TCH/H either, try dynamic TCH/F_PDCH */
-		if (!lchan) {
-			lchan = _lc_dyn_find_bts(bts, GSM_PCHAN_TCH_F_PDCH,
-						 GSM_PCHAN_TCH_F);
-			/* TCH/F_PDCH used as TCH/F -- here, type is already
-			 * set to GSM_LCHAN_TCH_F, but for clarity's sake... */
-			if (lchan)
-				type = GSM_LCHAN_TCH_F;
-		}
-
-		/* Try fully dynamic TCH/F_TCH/H_PDCH as TCH/F... */
-		if (!lchan && bts->network->dyn_ts_allow_tch_f) {
-			lchan = _lc_dyn_find_bts(bts,
-						 GSM_PCHAN_TCH_F_TCH_H_PDCH,
-						 GSM_PCHAN_TCH_F);
-			if (lchan)
-				type = GSM_LCHAN_TCH_F;
-		}
-		/* ...and as TCH/H. */
-		if (!lchan) {
-			lchan = _lc_dyn_find_bts(bts,
-						 GSM_PCHAN_TCH_F_TCH_H_PDCH,
-						 GSM_PCHAN_TCH_H);
-			if (lchan)
-				type = GSM_LCHAN_TCH_H;
-		}
-		break;
-	case GSM_LCHAN_TCH_H:
-		lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_H);
-		/* If we don't have TCH/H available, fall-back to TCH/F */
-		if (!lchan) {
-			lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_F);
-			if (lchan)
-				type = GSM_LCHAN_TCH_F;
-		}
-		/* No dedicated TCH/x available -- try fully dynamic
-		 * TCH/F_TCH/H_PDCH */
-		if (!lchan) {
-			lchan = _lc_dyn_find_bts(bts,
-						 GSM_PCHAN_TCH_F_TCH_H_PDCH,
-						 GSM_PCHAN_TCH_H);
-			if (lchan)
-				type = GSM_LCHAN_TCH_H;
-		}
-		/*
-		 * No need to check TCH/F_TCH/H_PDCH channels for TCH/F:
-		 * if no TCH/H was available, neither will be TCH/F.
-		 */
-		/* If we don't have TCH/F either, try dynamic TCH/F_PDCH */
-		if (!lchan) {
-			lchan = _lc_dyn_find_bts(bts, GSM_PCHAN_TCH_F_PDCH,
-						 GSM_PCHAN_TCH_F);
-			if (lchan)
-				type = GSM_LCHAN_TCH_F;
-		}
-		break;
-	default:
-		LOGP(DRLL, LOGL_ERROR, "Unknown gsm_chan_t %u\n", type);
-	}
-
-	if (lchan) {
-		lchan->type = type;
-
-		LOGP(DRLL, LOGL_INFO, "%s Allocating lchan=%u as %s\n",
-		     gsm_ts_and_pchan_name(lchan->ts),
-		     lchan->nr, gsm_lchant_name(lchan->type));
-
-		/* reset measurement report counter and index */
-	        lchan->meas_rep_count = 0;
-	        lchan->meas_rep_idx = 0;
-	        lchan->meas_rep_last_seen_nr = 255;
-
-		/* clear sapis */
-		memset(lchan->sapis, 0, ARRAY_SIZE(lchan->sapis));
-
-		/* clear multi rate config */
-		memset(&lchan->mr_ms_lv, 0, sizeof(lchan->mr_ms_lv));
-		memset(&lchan->mr_bts_lv, 0, sizeof(lchan->mr_bts_lv));
-		lchan->broken_reason = "";
-	} else {
-		struct challoc_signal_data sig;
-
-		LOGP(DRLL, LOGL_ERROR, "(bts=%d) Failed to allocate %s channel\n",
-		     bts->nr, gsm_lchant_name(type));
-
-		sig.bts = bts;
-		sig.type = type;
-		osmo_signal_dispatch(SS_CHALLOC, S_CHALLOC_ALLOC_FAIL, &sig);
-	}
-
-	return lchan;
-}
-
-/* Free a logical channel */
-void lchan_free(struct gsm_lchan *lchan)
-{
-	struct challoc_signal_data sig;
-	int i;
-
-	sig.type = lchan->type;
-	lchan->type = GSM_LCHAN_NONE;
-
-
-	if (lchan->conn
-	    && !(lchan->ts->pchan == GSM_PCHAN_TCH_F_TCH_H_PDCH
-		 && lchan->ts->dyn.pchan_is != lchan->ts->dyn.pchan_want)) {
-		struct lchan_signal_data sig;
-
-		/* We might kill an active channel... */
-		sig.lchan = lchan;
-		sig.mr = NULL;
-		osmo_signal_dispatch(SS_LCHAN, S_LCHAN_UNEXPECTED_RELEASE, &sig);
-	}
-
-	/* stop the timer */
-	osmo_timer_del(&lchan->T3101);
-
-	/* clear cached measuement reports */
-	lchan->meas_rep_idx = 0;
-	for (i = 0; i < ARRAY_SIZE(lchan->meas_rep); i++) {
-		lchan->meas_rep[i].flags = 0;
-		lchan->meas_rep[i].nr = 0;
-	}
-	for (i = 0; i < ARRAY_SIZE(lchan->neigh_meas); i++)
-		lchan->neigh_meas[i].arfcn = 0;
-
-	if (lchan->rqd_ref) {
-		talloc_free(lchan->rqd_ref);
-		lchan->rqd_ref = NULL;
-		lchan->rqd_ta = 0;
-	}
-
-	sig.lchan = lchan;
-	sig.bts = lchan->ts->trx->bts;
-	osmo_signal_dispatch(SS_CHALLOC, S_CHALLOC_FREED, &sig);
-
-	if (lchan->conn
-	    && !(lchan->ts->pchan == GSM_PCHAN_TCH_F_TCH_H_PDCH
-		 && lchan->ts->dyn.pchan_is != lchan->ts->dyn.pchan_want)) {
-		LOGP(DRLL, LOGL_ERROR, "the subscriber connection should be gone.\n");
-		lchan->conn = NULL;
-	}
-
-	/* FIXME: ts_free() the timeslot, if we're the last logical
-	 * channel using it */
-
-	/* reset RTP voice connection related data */
-	memset(&lchan->abis_ip, 0, sizeof(lchan->abis_ip));
-}
-
-/*
- * There was an error with the TRX and we need to forget
- * any state so that a lchan can be allocated again after
- * the trx is fully usable.
- *
- * This should be called after lchan_free to force a channel
- * be available for allocation again. This means that this
- * method will stop the "delay after error"-timer and set the
- * state to LCHAN_S_NONE.
- */
-void lchan_reset(struct gsm_lchan *lchan)
-{
-	osmo_timer_del(&lchan->T3101);
-	osmo_timer_del(&lchan->T3109);
-	osmo_timer_del(&lchan->T3111);
-	osmo_timer_del(&lchan->error_timer);
-
-	lchan->type = GSM_LCHAN_NONE;
-	rsl_lchan_set_state(lchan, LCHAN_S_NONE);
-}
-
-/* Drive the release process of the lchan */
-static void _lchan_handle_release(struct gsm_lchan *lchan,
-				  int sacch_deact, int mode)
-{
-	/* Release all SAPIs on the local end and continue */
-	rsl_release_sapis_from(lchan, 1, RSL_REL_LOCAL_END);
-
-	/*
-	 * Shall we send a RR Release, start T3109 and wait for the
-	 * release indication from the BTS or just take it down (e.g.
-	 * on assignment requests)
-	 */
-	if (sacch_deact) {
-		gsm48_send_rr_release(lchan);
-
-		/* Deactivate the SACCH on the BTS side */
-		rsl_deact_sacch(lchan);
-		rsl_start_t3109(lchan);
-	} else if (lchan->sapis[0] == LCHAN_SAPI_UNUSED) {
-		rsl_direct_rf_release(lchan);
-	} else {
-		rsl_release_request(lchan, 0, mode);
-	}
-}
-
-/* Consider releasing the channel now */
-int lchan_release(struct gsm_lchan *lchan, int sacch_deact, enum rsl_rel_mode mode)
-{
-	DEBUGP(DRLL, "%s starting release sequence\n", gsm_lchan_name(lchan));
-	rsl_lchan_set_state(lchan, LCHAN_S_REL_REQ);
-
-	lchan->conn = NULL;
-	_lchan_handle_release(lchan, sacch_deact, mode);
-	return 1;
-}
-
 void bts_chan_load(struct pchan_load *cl, const struct gsm_bts *bts)
 {
 	struct gsm_bts_trx *trx;
@@ -615,22 +51,18 @@ void bts_chan_load(struct pchan_load *cl, const struct gsm_bts *bts)
 
 		for (i = 0; i < ARRAY_SIZE(trx->ts); i++) {
 			struct gsm_bts_trx_ts *ts = &trx->ts[i];
-			struct load_counter *pl = &cl->pchan[ts->pchan];
-			int j;
-			int subslots;
+			struct load_counter *pl = &cl->pchan[ts->pchan_on_init];
+			struct gsm_lchan *lchan;
 
 			/* skip administratively deactivated timeslots */
 			if (!nm_is_running(&ts->mo.nm_state))
 				continue;
 
-			subslots = ts_subslots(ts);
-			for (j = 0; j < subslots; j++) {
-				struct gsm_lchan *lchan = &ts->lchan[j];
-
+			ts_for_each_lchan(lchan, ts) {
 				pl->total++;
 
-				switch (lchan->state) {
-				case LCHAN_S_NONE:
+				switch (lchan->fi->state) {
+				case LCHAN_ST_UNUSED:
 					break;
 				default:
 					pl->used++;