fix nanobts: timeslot FSM: use flags to remember OML,RSL status

Before this patch, the timeslot FSM receives OML and RSL ready events.
Afterwards, it relies on examining the RSL and OML status to match the received
events. This doesn't work for the ip.access nanobts, which fails to change the
CHANNEL OM's operational status even though it has sent an Opstart ACK.  We
receive OML CHANNEL Opstart ACK, but the mo's state left at OP_STATE=Disabled.
We apparently cannot rely on the gsm_abis_mo state as assumed before this
patch, since changing the state depends on each BTS vendor's OML
implementation.

Also, implementation wise, it is better to not include assumptions on RSL and
OML implementations in the timeslot FSM. Simply receive the OML and RSL ready
events and remember that they arrived in dedicated flags.

Remove the no longer needed oml_is_ts_ready() callback from struct
gsm_bts_model added in:

  commit 91aa68f762218906e45be4817c6ea54b480da5e1
  "dyn TS: init only when both RSL and the Channel OM are established"
  I99f29d2ba079f6f4b77f0af12d9784588d2f56b3

This keeps osmo-bts operational while fixing ip.access nanobts, where the
CHANNEL OM's state prevented the timeslot FSM from entering operation.

Change-Id: I4843d03b3237cdcca0ad2041ef6895ff253d8419

1 files changed, 5 insertions, 1 deletions

diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index ce563ef17..750c02794 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -605,6 +605,11 @@ struct gsm_bts_trx_ts {
 	 * enters IN_USE state, i.e. after each TCH use we try to PDCH ACT once again. */
 	bool pdch_act_allowed;
 
+	/* Whether TS_EV_OML_READY was received */
+	bool is_oml_ready;
+	/* Whether TS_EV_RSL_READY was received */
+	bool is_rsl_ready;
+
 	struct gsm_abis_mo mo;
 	struct tlv_parsed nm_attr;
 	uint8_t nm_chan_comb;
@@ -739,7 +744,6 @@ struct gsm_bts_model {
 	int (*start)(struct gsm_network *net);
 	int (*oml_rcvmsg)(struct msgb *msg);
 	char * (*oml_status)(const struct gsm_bts *bts);
-	bool (*oml_is_ts_ready)(const struct gsm_bts_trx_ts *ts);
 
 	void (*e1line_bind_ops)(struct e1inp_line *line);