assignment_fsm: Properly support assigning signalling mode TCH/x

To support the 3 possible preferences, the changes needed were:
 - Replace 'full_rate' bool with a 3 option enum to represent
   the channels types for signalling
 - Switch from _pref/_alt to using an array sorted in preference
   order

Change-Id: I4c7499c8c866ea3ff7b1327edb3615d003d927d3
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>

2 files changed, 11 insertions, 8 deletions

diff --git a/include/osmocom/bsc/gsm_data.h b/include/osmocom/bsc/gsm_data.h
index c4315c07f..fb0735aee 100644
--- a/include/osmocom/bsc/gsm_data.h
+++ b/include/osmocom/bsc/gsm_data.h
@@ -98,9 +98,15 @@ enum subscr_sccp_state {
 	SUBSCR_SCCP_ST_CONNECTED
 };
 
+enum channel_rate {
+	CH_RATE_SDCCH,
+	CH_RATE_HALF,
+	CH_RATE_FULL,
+};
+
 struct channel_mode_and_rate {
 	enum gsm48_chan_mode chan_mode;
-	bool full_rate;
+	enum channel_rate chan_rate;
 	uint16_t s15_s0;
 };
 
@@ -115,12 +121,9 @@ struct assignment_request {
 	char msc_rtp_addr[INET_ADDRSTRLEN];
 	uint16_t msc_rtp_port;
 
-	/* Prefered rate/codec setting (mandatory) */
-	struct channel_mode_and_rate ch_mode_rate_pref;
-
-	/* Alternate rate/codec setting (optional) */
-	bool ch_mode_rate_alt_present;
-	struct channel_mode_and_rate ch_mode_rate_alt;
+	/* Rate/codec setting in preference order (need at least 1 !) */
+	int n_ch_mode_rate;
+	struct channel_mode_and_rate ch_mode_rate[3];
 };
 
 /* State of an ongoing Assignment, while the assignment_fsm is still busy. This serves as state separation to keep the
diff --git a/include/osmocom/bsc/lchan_select.h b/include/osmocom/bsc/lchan_select.h
index 4aecdf676..865181bf5 100644
--- a/include/osmocom/bsc/lchan_select.h
+++ b/include/osmocom/bsc/lchan_select.h
@@ -3,4 +3,4 @@
 
 struct gsm_lchan *lchan_select_by_type(struct gsm_bts *bts, enum gsm_chan_t type);
 struct gsm_lchan *lchan_select_by_chan_mode(struct gsm_bts *bts,
-					    enum gsm48_chan_mode chan_mode, bool full_rate);
+					    enum gsm48_chan_mode chan_mode, enum channel_rate chan_rate);