Change in osmocom-bb[master]: l1ctl_proto.h: extend ccch_mode enum with CBCH

[Vadim Yanitskiy]

Vadim Yanitskiy has uploaded this change for review. ( https://gerrit.osmocom.org/11183


Change subject: l1ctl_proto.h: extend ccch_mode enum with CBCH
......................................................................

l1ctl_proto.h: extend ccch_mode enum with CBCH

According to GSM TS 05.02, there are two ways to enable CBCH:

  a) replace sub-slot number 2 of CCCH+SDCCH/4 (comb. V),
  b) replace sub-slot number 2 of SDCCH/8 (comb. VII).

Unlike SDCCH/8 (case b), CCCH+SDCCH/4 can be allocated on TS0
only, and shall not use frequency hopping. This means that
implementing CBCH support on SDCCH/8 would require much more
efforts than on combined CCCH+SDCCH/4, as in last case CBCH
messages can be received without the need to switch from
idle to dedicated mode.

This change introduces a new ccch_mode item, which should be
used by the higher layers to indicate presence of CBCH channel
on C0/TS0, so the PHY would enable decoding of CBCH messages
on CCCH+SDCCH/4 (case a) in idle mode.

Regarding to CBCH on SDCCH/8 (case b), it makes sense to
extend the 'l1ctl_dm_est_req', so it would be handled in
dedicated mode on request from the higher layers.

Change-Id: Ia94ebf22a2ec439dfe1f31d703b832ae57b48ef2
---
M include/l1ctl_proto.h
M src/host/trxcon/l1ctl.c
M src/target/firmware/layer1/l23_api.c
M src/target/firmware/layer1/prim_fbsb.c
4 files changed, 11 insertions(+), 1 deletion(-)



  git pull ssh://gerrit.osmocom.org:29418/osmocom-bb refs/changes/83/11183/1

diff --git a/include/l1ctl_proto.h b/include/l1ctl_proto.h
index 9d548bc..f1bff86 100644
--- a/include/l1ctl_proto.h
+++ b/include/l1ctl_proto.h
@@ -70,6 +70,7 @@
 	CCCH_MODE_NONE = 0,
 	CCCH_MODE_NON_COMBINED,
 	CCCH_MODE_COMBINED,
+	CCCH_MODE_COMBINED_CBCH,
 };
 
 enum neigh_mode {
diff --git a/src/host/trxcon/l1ctl.c b/src/host/trxcon/l1ctl.c
index f7f48af..83cdc2e 100644
--- a/src/host/trxcon/l1ctl.c
+++ b/src/host/trxcon/l1ctl.c
@@ -264,9 +264,10 @@
 	case CCCH_MODE_NONE:
 		return GSM_PCHAN_CCCH;
 
-	/* TODO: distinguish CBCH */
 	case CCCH_MODE_COMBINED:
 		return GSM_PCHAN_CCCH_SDCCH4;
+	case CCCH_MODE_COMBINED_CBCH:
+		return GSM_PCHAN_CCCH_SDCCH4_CBCH;
 
 	default:
 		LOGP(DL1C, LOGL_NOTICE, "Undandled CCCH mode (%u), "
diff --git a/src/target/firmware/layer1/l23_api.c b/src/target/firmware/layer1/l23_api.c
index e46ca09..311c521 100644
--- a/src/target/firmware/layer1/l23_api.c
+++ b/src/target/firmware/layer1/l23_api.c
@@ -479,6 +479,10 @@
 		mframe_enable(MF_TASK_CCCH_COMB);
 	else if (ccch_mode == CCCH_MODE_NON_COMBINED)
 		mframe_enable(MF_TASK_CCCH);
+	else if (ccch_mode == CCCH_MODE_COMBINED_CBCH) {
+		mframe_enable(MF_TASK_CCCH_COMB);
+		mframe_enable(MF_TASK_SDCCH4_CBCH);
+	}
 
 	l1ctl_tx_ccch_mode_conf(ccch_mode);
 }
diff --git a/src/target/firmware/layer1/prim_fbsb.c b/src/target/firmware/layer1/prim_fbsb.c
index 9eb56c6..50acefc 100644
--- a/src/target/firmware/layer1/prim_fbsb.c
+++ b/src/target/firmware/layer1/prim_fbsb.c
@@ -262,6 +262,10 @@
 		mframe_enable(MF_TASK_CCCH_COMB);
 	else if (l1s.serving_cell.ccch_mode == CCCH_MODE_NON_COMBINED)
 		mframe_enable(MF_TASK_CCCH);
+	else if (l1s.serving_cell.ccch_mode == CCCH_MODE_COMBINED_CBCH) {
+		mframe_enable(MF_TASK_CCCH_COMB);
+		mframe_enable(MF_TASK_SDCCH4_CBCH);
+	}
 
 	l1s_compl_sched(L1_COMPL_FB);
 

-- 
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Gerrit-Project: osmocom-bb
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: Ia94ebf22a2ec439dfe1f31d703b832ae57b48ef2
Gerrit-Change-Number: 11183
Gerrit-PatchSet: 1
Gerrit-Owner: Vadim Yanitskiy <axilirator at gmail.com>
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