DTX DL AMR: rewrite FSM recursion

Add explicit state for recursion (sending the different payload data in
response to the RTS request for same FN) and corresponding
transition. Remove ST_FACCH_V as with new explicit recursion handling it
becomes unreacheable. This makes it easier to maintain
preemption (interruption of current procedure due to FACCH or
Inhibition). This also reduces the number of possible transitions out of
each state thus reducing graph's cyclomatic complexity.

Change-Id: If39b68083d23a4a35f468a5d75f54eb733ebfd14

1 files changed, 93 insertions, 54 deletions

diff --git a/src/common/dtx_dl_amr_fsm.c b/src/common/dtx_dl_amr_fsm.c
index 50759572..d903b0cf 100644
--- a/src/common/dtx_dl_amr_fsm.c
+++ b/src/common/dtx_dl_amr_fsm.c
@@ -96,11 +96,8 @@ void dtx_fsm_sid_f2(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 void dtx_fsm_f1_inh(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 {
 	switch (event) {
-	case E_VOICE:
-		osmo_fsm_inst_state_chg(fi, ST_ONSET_V, 0, 0);
-		break;
-	case E_FACCH:
-		osmo_fsm_inst_state_chg(fi, ST_ONSET_F, 0, 0);
+	case E_COMPL:
+		osmo_fsm_inst_state_chg(fi, ST_F1_INH_REC, 0, 0);
 		break;
 	default:
 		LOGP(DL1P, LOGL_ERROR, "Unexpected event %d\n", event);
@@ -112,11 +109,34 @@ void dtx_fsm_f1_inh(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 void dtx_fsm_u_inh(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 {
 	switch (event) {
-	case E_VOICE:
+	case E_COMPL:
+		osmo_fsm_inst_state_chg(fi, ST_U_INH_REC, 0, 0);
+		break;
+	default:
+		LOGP(DL1P, LOGL_ERROR, "Unexpected event %d\n", event);
+		OSMO_ASSERT(0);
+		break;
+	}
+}
+
+void dtx_fsm_f1_inh_rec(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	switch (event) {
+	case E_COMPL:
 		osmo_fsm_inst_state_chg(fi, ST_VOICE, 0, 0);
 		break;
-	case E_FACCH:
-		osmo_fsm_inst_state_chg(fi, ST_FACCH, 0, 0);
+	default:
+		LOGP(DL1P, LOGL_ERROR, "Unexpected event %d\n", event);
+		OSMO_ASSERT(0);
+		break;
+	}
+}
+
+void dtx_fsm_u_inh_rec(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	switch (event) {
+	case E_COMPL:
+		osmo_fsm_inst_state_chg(fi, ST_VOICE, 0, 0);
 		break;
 	default:
 		LOGP(DL1P, LOGL_ERROR, "Unexpected event %d\n", event);
@@ -155,13 +175,8 @@ void dtx_fsm_sid_upd(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 void dtx_fsm_onset_v(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 {
 	switch (event) {
-	case E_SID_F:
-	case E_SID_U:
-	case E_VOICE:
-		osmo_fsm_inst_state_chg(fi, ST_VOICE, 0, 0);
-		break;
-	case E_FACCH:
-		osmo_fsm_inst_state_chg(fi, ST_FACCH_V, 0, 0);
+	case E_COMPL:
+		osmo_fsm_inst_state_chg(fi, ST_ONSET_V_REC, 0, 0);
 		break;
 	default:
 		LOGP(DL1P, LOGL_ERROR, "Unexpected event %d\n", event);
@@ -173,14 +188,8 @@ void dtx_fsm_onset_v(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 void dtx_fsm_onset_f(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 {
 	switch (event) {
-	case E_SID_F:
-	case E_SID_U:
-		break;
-	case E_VOICE:
-		osmo_fsm_inst_state_chg(fi, ST_VOICE, 0, 0);
-		break;
-	case E_FACCH:
-		osmo_fsm_inst_state_chg(fi, ST_FACCH, 0, 0);
+	case E_COMPL:
+		osmo_fsm_inst_state_chg(fi, ST_ONSET_F_REC, 0, 0);
 		break;
 	default:
 		LOGP(DL1P, LOGL_ERROR, "Unexpected event %d\n", event);
@@ -189,17 +198,24 @@ void dtx_fsm_onset_f(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 	}
 }
 
-void dtx_fsm_facch_v(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+void dtx_fsm_onset_v_rec(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 {
 	switch (event) {
-	case E_FACCH:
-		break;
-	case E_VOICE:
+	case E_COMPL:
 		osmo_fsm_inst_state_chg(fi, ST_VOICE, 0, 0);
 		break;
-	case E_SID_U:
+	default:
+		LOGP(DL1P, LOGL_ERROR, "Unexpected event %d\n", event);
+		OSMO_ASSERT(0);
 		break;
-	case E_SID_F:
+	}
+}
+
+void dtx_fsm_onset_f_rec(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+{
+	switch (event) {
+	case E_COMPL:
+		osmo_fsm_inst_state_chg(fi, ST_FACCH, 0, 0);
 		break;
 	default:
 		LOGP(DL1P, LOGL_ERROR, "Unexpected event %d\n", event);
@@ -211,13 +227,14 @@ void dtx_fsm_facch_v(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 void dtx_fsm_facch(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 {
 	switch (event) {
+	case E_SID_U:
+	case E_SID_F:
 	case E_FACCH:
 		break;
 	case E_VOICE:
 		osmo_fsm_inst_state_chg(fi, ST_VOICE, 0, 0);
 		break;
-	case E_SID_U:
-	case E_SID_F:
+	case E_COMPL:
 		osmo_fsm_inst_state_chg(fi, ST_SID_F1, 0, 0);
 		break;
 	default:
@@ -244,29 +261,43 @@ static struct osmo_fsm_state dtx_dl_amr_fsm_states[] = {
 		.action = dtx_fsm_sid_f1,
 	},
 	/* SID-FIRST P2 (only for AMR HR):
-	   actual start of silence period in case of AMR HR*/
+	   actual start of silence period in case of AMR HR */
 	[ST_SID_F2]= {
 		.in_event_mask = X(E_SID_U) | X(E_VOICE) | X(E_FACCH) | X(E_ONSET),
 		.out_state_mask = X(ST_SID_U) | X(ST_VOICE) | X(ST_ONSET_F) | X(ST_ONSET_V),
 		.name = "SID-FIRST (P2)",
 		.action = dtx_fsm_sid_f2,
 	},
-	/* SID-FIRST Inhibited:
-	   incoming SPEECH or FACCH (only for AMR HR) */
+	/* SID-FIRST Inhibited: incoming SPEECH (only for AMR HR) */
 	[ST_F1_INH]= {
-		.in_event_mask = X(E_VOICE) | X(E_FACCH),
-		.out_state_mask = X(ST_VOICE) | X(ST_FACCH_V),
+		.in_event_mask = X(E_COMPL),
+		.out_state_mask = X(ST_F1_INH_REC),
 		.name = "SID-FIRST (Inh)",
 		.action = dtx_fsm_f1_inh,
 	},
-	/* SID-UPDATE Inhibited:
-	   incoming SPEECH or FACCH (only for AMR HR) */
+	/* SID-UPDATE Inhibited: incoming SPEECH (only for AMR HR) */
 	[ST_U_INH]= {
-		.in_event_mask = X(E_VOICE) | X(E_FACCH),
-		.out_state_mask = X(ST_VOICE) | X(ST_FACCH),
+		.in_event_mask = X(E_COMPL),
+		.out_state_mask = X(ST_U_INH_REC),
 		.name = "SID-UPDATE (Inh)",
 		.action = dtx_fsm_u_inh,
 	},
+	/* SID-FIRST Inhibition recursion in progress:
+	   Inhibit itself was already sent, now have to send the voice that caused it */
+	[ST_F1_INH_REC]= {
+		.in_event_mask = X(E_COMPL),
+		.out_state_mask = X(ST_VOICE),
+		.name = "SID-FIRST (Inh, Rec)",
+		.action = dtx_fsm_f1_inh_rec,
+	},
+	/* SID-UPDATE Inhibition recursion in progress:
+	   Inhibit itself was already sent, now have to send the voice that caused it */
+	[ST_U_INH_REC]= {
+		.in_event_mask = X(E_COMPL),
+		.out_state_mask = X(ST_VOICE),
+		.name = "SID-UPDATE (Inh, Rec)",
+		.action = dtx_fsm_u_inh_rec,
+	},
 	/* Silence period with periodic comfort noise data updates */
 	[ST_SID_U]= {
 		.in_event_mask = X(E_FACCH) | X(E_VOICE) | X(E_INHIB) | X(E_SID_U) | X(E_SID_F) | X(E_ONSET),
@@ -276,31 +307,39 @@ static struct osmo_fsm_state dtx_dl_amr_fsm_states[] = {
 	},
 	/* ONSET - end of silent period due to incoming SPEECH frame */
 	[ST_ONSET_V]= {
-		.in_event_mask = X(E_SID_F) | X(E_SID_U) | X(E_VOICE) | X(E_FACCH),
-		.out_state_mask = X(ST_VOICE) | X(ST_FACCH_V),
+		.in_event_mask = X(E_COMPL),
+		.out_state_mask = X(ST_ONSET_V_REC),
 		.name = "ONSET (SPEECH)",
 		.action = dtx_fsm_onset_v,
 	},
 	/* ONSET - end of silent period due to incoming FACCH frame */
 	[ST_ONSET_F]= {
-		.in_event_mask = X(E_VOICE) | X(E_FACCH) | X(E_SID_U) | X(E_SID_F),
-		.out_state_mask = X(ST_VOICE) | X(ST_FACCH),
+		.in_event_mask = X(E_COMPL),
+		.out_state_mask = X(ST_ONSET_F_REC),
 		.name = "ONSET (FACCH)",
 		.action = dtx_fsm_onset_f,
 	},
-	/* FACCH sending state: SPEECH was observed before so once we're done
-	   FSM should get back to VOICE state */
-	[ST_FACCH_V]= {
-		.in_event_mask = X(E_FACCH) | X(E_VOICE) | X(E_SID_U) | X(E_SID_F),
-		.out_state_mask = X(ST_FACCH_V) | X(ST_VOICE) | X(ST_SID_F1),
-		.name = "FACCH (SPEECH)",
-		.action = dtx_fsm_facch_v,
+	/* ONSET recursion in progress:
+	   ONSET itself was already sent, now have to send the voice that caused it */
+	[ST_ONSET_V_REC]= {
+		.in_event_mask = X(E_COMPL),
+		.out_state_mask = X(ST_VOICE),
+		.name = "ONSET (SPEECH, Rec)",
+		.action = dtx_fsm_onset_v_rec,
+	},
+	/* ONSET recursion in progress:
+	   ONSET itself was already sent, now have to send the data that caused it */
+	[ST_ONSET_F_REC]= {
+		.in_event_mask = X(E_COMPL),
+		.out_state_mask = X(ST_FACCH),
+		.name = "ONSET (FACCH, Rec)",
+		.action = dtx_fsm_onset_f_rec,
 	},
 	/* FACCH sending state: no SPEECH was observed before so once we're done
 	   FSM should get back to silent period via SID-FIRST */
 	[ST_FACCH]= {
-		.in_event_mask = X(E_FACCH) | X(E_VOICE) | X(E_SID_U) | X(E_SID_F),
-		.out_state_mask = X(ST_FACCH_V) | X(ST_VOICE) | X(ST_SID_F1),
+		.in_event_mask = X(E_FACCH) | X(E_VOICE) | X(E_COMPL) | X(E_SID_U) | X(E_SID_F),
+		.out_state_mask = X(ST_VOICE) | X(ST_SID_F1),
 		.name = "FACCH",
 		.action = dtx_fsm_facch,
 	},
@@ -310,7 +349,7 @@ const struct value_string dtx_dl_amr_fsm_event_names[] = {
 	{ E_VOICE,	"Voice" },
 	{ E_ONSET,	"ONSET" },
 	{ E_FACCH,	"FACCH" },
-	{ E_COMPL,	"Complete P1 -> P2" },
+	{ E_COMPL,	"Complete" },
 	{ E_INHIB,	"Inhibit" },
 	{ E_SID_F,	"SID-FIRST" },
 	{ E_SID_U,	"SID-UPDATE" },