ta: Create TimingAdvance class and make it belong to the BTS

This allows us to easily flush the state in case a PCU/BTS
connection is lost.

TODO

@@ -7,3 +7,4 @@
 * Replace trx/ts with pointers. E.g. a PDCH should know the trx
   it is on... then we can omit trx, ts and parameters and just pass
   the pdch.
+* On global free/reset... also flush the timing advance..

src/Makefile.am

@@ -82,7 +82,8 @@ noinst_HEADERS = \
 	tbf.h \
 	bts.h \
 	poll_controller.h \
-	encoding.h
+	encoding.h \
+	ta.h
 
 osmo_pcu_SOURCES = pcu_main.cpp
 

src/bts.h

@@ -28,6 +28,7 @@ extern "C" {
 }
 
 #include "poll_controller.h"
+#include "ta.h"
 #endif
 
 #include <stdint.h>
@@ -122,6 +123,7 @@ public:
 	static BTS* main_bts();
 
 	struct gprs_rlcmac_bts *bts_data();
+	TimingAdvance *timing_advance();
 
 	/** TODO: change the number to unsigned */
 	void set_current_frame_number(int frame_number);
@@ -134,6 +136,7 @@ private:
 	int m_cur_fn;
 	struct gprs_rlcmac_bts m_bts;
 	PollController m_pollController;
+	TimingAdvance m_ta;
 
 private:
 	/* disable copying to avoid slicing */
@@ -145,6 +148,11 @@ inline int BTS::current_frame_number() const
 {
 	return m_cur_fn;
 }
+
+inline TimingAdvance *BTS::timing_advance()
+{
+	return &m_ta;
+}
 #endif
 
 #ifdef __cplusplus

src/gprs_rlcmac.h

@@ -161,12 +161,6 @@ int gprs_rlcmac_rcv_rts_block(struct gprs_rlcmac_bts *bts,
 
 int gprs_rlcmac_imm_ass_cnf(uint8_t *data, uint32_t fn);
 
-int remember_timing_advance(uint32_t tlli, uint8_t ta);
-
-int recall_timing_advance(uint32_t tlli);
-
-int flush_timing_advance(void);
-
 extern "C" {
 #endif
 int alloc_algorithm_a(struct gprs_rlcmac_bts *bts,

src/gprs_rlcmac_data.cpp

@@ -397,14 +397,14 @@ int gprs_rlcmac_rcv_control_block(struct gprs_rlcmac_bts *bts,
 						"in packet ressource request of single "
 						"block, but there is no resource request "
 						"scheduled!\n");
-					rc = recall_timing_advance(tlli);
+					rc = bts->bts->timing_advance()->recall(tlli);
 					if (rc >= 0)
 						ta = rc;
 					else
 						ta = 0;
 				} else {
 					ta = sba->ta;
-					remember_timing_advance(tlli, ta);
+					bts->bts->timing_advance()->remember(tlli, ta);
 					llist_del(&sba->list);
 					talloc_free(sba);
 				}
@@ -452,7 +452,7 @@ int gprs_rlcmac_rcv_control_block(struct gprs_rlcmac_bts *bts,
 				"block, but there is no resource request "
 				"scheduled!\n");
 		} else {
-			remember_timing_advance(ul_control_block->u.Packet_Measurement_Report.TLLI, sba->ta);
+			bts->bts->timing_advance()->remember(ul_control_block->u.Packet_Measurement_Report.TLLI, sba->ta);
 			llist_del(&sba->list);
 			talloc_free(sba);
 		}
@@ -820,7 +820,7 @@ int gprs_rlcmac_rcv_data_block_acknowledged(struct gprs_rlcmac_bts *bts,
 		/* mark TLLI valid now */
 		tbf->tlli_valid = 1;
 		/* store current timing advance */
-		remember_timing_advance(tbf->tlli, tbf->ta);
+		bts->bts->timing_advance()->remember(tbf->tlli, tbf->ta);
 	/* already have TLLI, but we stille get another one */
 	} else if (rh->ti) {
 		uint32_t tlli;

src/pcu_main.cpp

@@ -250,7 +250,7 @@ int main(int argc, char *argv[])
 
 	pcu_l1if_close();
 
-	flush_timing_advance();
+	bts->bts->timing_advance()->flush();
 
 	talloc_report_full(tall_pcu_ctx, stderr);
 	talloc_free(tall_pcu_ctx);

src/ta.cpp

@@ -19,6 +19,7 @@
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  */
 
+#include <ta.h>
 #include <gprs_rlcmac.h>
 
 extern "C" {
@@ -36,22 +37,25 @@ extern void *tall_pcu_ctx;
 /* enable to debug timing advance memory */
 //#define DEBUG_TA
 
-static LLIST_HEAD(gprs_rlcmac_ta_list);
-static int gprs_rlcmac_ta_num = 0;
-
 struct gprs_rlcmac_ta {
 	struct llist_head	list;
 	uint32_t		tlli;
 	uint8_t			ta;
 };
 
+TimingAdvance::TimingAdvance()
+	: m_ta_len(0)
+{
+	INIT_LLIST_HEAD(&m_ta_list);
+}
+
 /* remember timing advance of a given TLLI */
-int remember_timing_advance(uint32_t tlli, uint8_t ta)
+int TimingAdvance::remember(uint32_t tlli, uint8_t ta)
 {
 	struct gprs_rlcmac_ta *ta_entry;
 
 	/* check for existing entry */
-	llist_for_each_entry(ta_entry, &gprs_rlcmac_ta_list, list) {
+	llist_for_each_entry(ta_entry, &m_ta_list, list) {
 		if (ta_entry->tlli == tlli) {
 #ifdef DEBUG_TA
 			fprintf(stderr, "update %08x %d\n", tlli, ta);
@@ -59,7 +63,7 @@ int remember_timing_advance(uint32_t tlli, uint8_t ta)
 			ta_entry->ta = ta;
 			/* relink to end of list */
 			llist_del(&ta_entry->list);
-			llist_add_tail(&ta_entry->list, &gprs_rlcmac_ta_list);
+			llist_add_tail(&ta_entry->list, &m_ta_list);
 			return 0;
 		}
 	}
@@ -68,12 +72,12 @@ int remember_timing_advance(uint32_t tlli, uint8_t ta)
 	fprintf(stderr, "remember %08x %d\n", tlli, ta);
 #endif
 	/* if list is full, remove oldest entry */
-	if (gprs_rlcmac_ta_num == 30) {
-		ta_entry = llist_entry(gprs_rlcmac_ta_list.next,
+	if (m_ta_len == 30) {
+		ta_entry = llist_entry(m_ta_list.next,
 			struct gprs_rlcmac_ta, list);
 	        llist_del(&ta_entry->list);
 		talloc_free(ta_entry);
-		gprs_rlcmac_ta_num--;
+		m_ta_len--;
 	}
 
 	/* create new TA entry */
@@ -83,18 +87,18 @@ int remember_timing_advance(uint32_t tlli, uint8_t ta)
 
 	ta_entry->tlli = tlli;
 	ta_entry->ta = ta;
-	llist_add_tail(&ta_entry->list, &gprs_rlcmac_ta_list);
-	gprs_rlcmac_ta_num++;
+	llist_add_tail(&ta_entry->list, &m_ta_list);
+	m_ta_len++;
 
 	return 0;
 }
 
-int recall_timing_advance(uint32_t tlli)
+int TimingAdvance::recall(uint32_t tlli)
 {
 	struct gprs_rlcmac_ta *ta_entry;
 	uint8_t ta;
 
-	llist_for_each_entry(ta_entry, &gprs_rlcmac_ta_list, list) {
+	llist_for_each_entry(ta_entry, &m_ta_list, list) {
 		if (ta_entry->tlli == tlli) {
 			ta = ta_entry->ta;
 #ifdef DEBUG_TA
@@ -110,13 +114,13 @@ int recall_timing_advance(uint32_t tlli)
 	return -EINVAL;
 }
 
-int flush_timing_advance(void)
+int TimingAdvance::flush()
 {
 	struct gprs_rlcmac_ta *ta_entry;
 	int count = 0;
 
-	while (!llist_empty(&gprs_rlcmac_ta_list)) {
-		ta_entry = llist_entry(gprs_rlcmac_ta_list.next,
+	while (!llist_empty(&m_ta_list)) {
+		ta_entry = llist_entry(m_ta_list.next,
 			struct gprs_rlcmac_ta, list);
 #ifdef DEBUG_TA
 		fprintf(stderr, "flush entry %08x %d\n", ta_entry->tlli,
@@ -126,7 +130,7 @@ int flush_timing_advance(void)
 		talloc_free(ta_entry);
 		count++;
 	}
-	gprs_rlcmac_ta_num = 0;
+	m_ta_len = 0;
 
 	return count;
 }

src/ta.h

@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2012 Ivan Klyuchnikov
+ * Copyright (C) 2012 Andreas Eversberg <jolly@eversberg.eu>
+ * Copyright (C) 2013 by Holger Hans Peter Freyther
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+#pragma once
+
+extern "C" {
+#include <osmocom/core/linuxlist.h>
+}
+
+#include <stdint.h>
+
+class TimingAdvance {
+public:
+	TimingAdvance();
+
+	int remember(uint32_t tlli, uint8_t ta);
+	int recall(uint32_t tlli);
+	int flush();
+
+private:
+	size_t m_ta_len;
+	llist_head m_ta_list;	
+};

src/tbf.cpp

@@ -135,7 +135,7 @@ static int tbf_new_dl_assignment(struct gprs_rlcmac_bts *bts,
 			ta = tbf->ta;
 		else {
 			/* recall TA */
-			rc = recall_timing_advance(tlli);
+			rc = bts->bts->timing_advance()->recall(tlli);
 			if (rc < 0) {
 				LOGP(DRLCMAC, LOGL_NOTICE, "TA unknown"
 					", assuming 0\n");