Bluetooth: Controller: Fix incorrect elapsed events value

Fix incorrect elapsed events value when LLL event prepare_cb
was invoked but was aborted before anchor point sync. This
caused premature supervision timeouts under applications
configured with CONFIG_BT_CTLR_EVENT_OVERHEAD_RESERVE_MAX=n
and CONFIG_BT_CTLR_PERIPHERAL_RESERVE_MAX=n.

Fixes commit 247037bd3e ("Bluetooth: Controller: Fix
incorrect elapsed events value").

Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>

subsys/bluetooth/controller/ll_sw/lll_sync_iso.h

@@ -30,8 +30,10 @@ struct lll_sync_iso {
 
 	uint16_t iso_interval;
 
+	uint16_t lazy_prepare;
 	uint16_t latency_prepare;
 	uint16_t latency_event;
+
 	union {
 		struct lll_sync_iso_data_chan data_chan;
 

subsys/bluetooth/controller/ll_sw/nordic/lll/lll_sync.c

@@ -46,7 +46,6 @@
 #include "hal/debug.h"
 
 static int init_reset(void);
-static void prepare(void *param);
 static int create_prepare_cb(struct lll_prepare_param *p);
 static int prepare_cb(struct lll_prepare_param *p);
 static int prepare_cb_common(struct lll_prepare_param *p, uint8_t chan_idx);
@@ -100,7 +99,9 @@ void lll_sync_create_prepare(void *param)
 {
 	int err;
 
-	prepare(param);
+	/* Request to start HF Clock */
+	err = lll_hfclock_on();
+	LL_ASSERT(err >= 0);
 
 	/* Invoke common pipeline handling of prepare */
 	err = lll_prepare(is_abort_cb, abort_cb, create_prepare_cb, 0, param);
@@ -111,35 +112,13 @@ void lll_sync_prepare(void *param)
 {
 	int err;
 
-	prepare(param);
-
-	/* Invoke common pipeline handling of prepare */
-	err = lll_prepare(is_abort_cb, abort_cb, prepare_cb, 0, param);
-	LL_ASSERT(!err || err == -EINPROGRESS);
-}
-
-static void prepare(void *param)
-{
-	struct lll_prepare_param *p;
-	struct lll_sync *lll;
-	int err;
-
 	/* Request to start HF Clock */
 	err = lll_hfclock_on();
 	LL_ASSERT(err >= 0);
 
-	p = param;
+	/* Invoke common pipeline handling of prepare */
-
+	err = lll_prepare(is_abort_cb, abort_cb, prepare_cb, 0, param);
-	lll = p->param;
+	LL_ASSERT(err == 0 || err == -EINPROGRESS);
-
-	lll->lazy_prepare = p->lazy;
-
-	/* Accumulate window widening */
-	lll->window_widening_prepare_us += lll->window_widening_periodic_us *
-					   (lll->lazy_prepare + 1U);
-	if (lll->window_widening_prepare_us > lll->window_widening_max_us) {
-		lll->window_widening_prepare_us = lll->window_widening_max_us;
-	}
 }
 
 void lll_sync_aux_prepare_cb(struct lll_sync *lll,
@@ -274,6 +253,7 @@ static int create_prepare_cb(struct lll_prepare_param *p)
 	lll = p->param;
 
 	/* Calculate the current event latency */
+	lll->lazy_prepare = p->lazy;
 	lll->skip_event = lll->skip_prepare + lll->lazy_prepare;
 
 	/* Calculate the current event counter value */
@@ -362,6 +342,7 @@ static int prepare_cb(struct lll_prepare_param *p)
 	lll = p->param;
 
 	/* Calculate the current event latency */
+	lll->lazy_prepare = p->lazy;
 	lll->skip_event = lll->skip_prepare + lll->lazy_prepare;
 
 	/* Calculate the current event counter value */
@@ -442,6 +423,13 @@ static int prepare_cb_common(struct lll_prepare_param *p, uint8_t chan_idx)
 
 	lll = p->param;
 
+	/* Accumulate window widening */
+	lll->window_widening_prepare_us += lll->window_widening_periodic_us *
+					   (lll->lazy_prepare + 1U);
+	if (lll->window_widening_prepare_us > lll->window_widening_max_us) {
+		lll->window_widening_prepare_us = lll->window_widening_max_us;
+	}
+
 	/* Current window widening */
 	lll->window_widening_event_us += lll->window_widening_prepare_us;
 	lll->window_widening_prepare_us = 0;
@@ -631,10 +619,20 @@ static void abort_cb(struct lll_prepare_param *prepare_param, void *param)
 	err = lll_hfclock_off();
 	LL_ASSERT(err >= 0);
 
-	/* Accumulate the latency as event is aborted while being in pipeline */
+	/* Get reference to LLL connection context */
 	lll = prepare_param->param;
+
+	/* Accumulate the latency as event is aborted while being in pipeline */
+	lll->lazy_prepare = prepare_param->lazy;
 	lll->skip_prepare += (lll->lazy_prepare + 1U);
 
+	/* Accumulate window widening */
+	lll->window_widening_prepare_us += lll->window_widening_periodic_us *
+					   (prepare_param->lazy + 1);
+	if (lll->window_widening_prepare_us > lll->window_widening_max_us) {
+		lll->window_widening_prepare_us = lll->window_widening_max_us;
+	}
+
 	/* Extra done event, to check sync lost */
 	e = ull_event_done_extra_get();
 	LL_ASSERT(e);

subsys/bluetooth/controller/ll_sw/nordic/lll/lll_sync_iso.c

@@ -40,9 +40,6 @@
 #include "hal/debug.h"
 
 static int init_reset(void);
-static void prepare(void *param);
-static void create_prepare_bh(void *param);
-static void prepare_bh(void *param);
 static int create_prepare_cb(struct lll_prepare_param *p);
 static int prepare_cb(struct lll_prepare_param *p);
 static int prepare_cb_common(struct lll_prepare_param *p);
@@ -101,14 +98,25 @@ int lll_sync_iso_reset(void)
 
 void lll_sync_iso_create_prepare(void *param)
 {
-	prepare(param);
+	int err;
-	create_prepare_bh(param);
+
+	err = lll_hfclock_on();
+	LL_ASSERT(err >= 0);
+
+	err = lll_prepare(is_abort_cb, abort_cb, create_prepare_cb, 0U,
+			  param);
+	LL_ASSERT(err == 0 || err == -EINPROGRESS);
 }
 
 void lll_sync_iso_prepare(void *param)
 {
-	prepare(param);
+	int err;
-	prepare_bh(param);
+
+	err = lll_hfclock_on();
+	LL_ASSERT(err >= 0);
+
+	err = lll_prepare(is_abort_cb, abort_cb, prepare_cb, 0U, param);
+	LL_ASSERT(err == 0 || err == -EINPROGRESS);
 }
 
 void lll_sync_iso_flush(uint8_t handle, struct lll_sync_iso *lll)
@@ -122,53 +130,6 @@ static int init_reset(void)
 	return 0;
 }
 
-static void prepare(void *param)
-{
-	struct lll_prepare_param *p;
-	struct lll_sync_iso *lll;
-	uint16_t elapsed;
-	int err;
-
-	err = lll_hfclock_on();
-	LL_ASSERT(err >= 0);
-
-	p = param;
-
-	/* Instants elapsed */
-	elapsed = p->lazy + 1U;
-
-	lll = p->param;
-
-	/* Save the (latency + 1) for use in event */
-	lll->latency_prepare += elapsed;
-
-	/* Accumulate window widening */
-	lll->window_widening_prepare_us += lll->window_widening_periodic_us *
-					   elapsed;
-	if (lll->window_widening_prepare_us > lll->window_widening_max_us) {
-		lll->window_widening_prepare_us = lll->window_widening_max_us;
-	}
-}
-
-static void create_prepare_bh(void *param)
-{
-	int err;
-
-	/* Invoke common pipeline handling of prepare */
-	err = lll_prepare(is_abort_cb, abort_cb, create_prepare_cb, 0U,
-			  param);
-	LL_ASSERT(!err || err == -EINPROGRESS);
-}
-
-static void prepare_bh(void *param)
-{
-	int err;
-
-	/* Invoke common pipeline handling of prepare */
-	err = lll_prepare(is_abort_cb, abort_cb, prepare_cb, 0U, param);
-	LL_ASSERT(!err || err == -EINPROGRESS);
-}
-
 static int create_prepare_cb(struct lll_prepare_param *p)
 {
 	int err;
@@ -225,18 +186,26 @@ static int prepare_cb_common(struct lll_prepare_param *p)
 
 	lll = p->param;
 
-	/* Deduce the latency */
+	/* Calculate the current event latency */
-	lll->latency_event = lll->latency_prepare - 1U;
+	lll->lazy_prepare = p->lazy;
+	lll->latency_event = lll->latency_prepare + lll->lazy_prepare;
 
 	/* Calculate the current event counter value */
 	event_counter = (lll->payload_count / lll->bn) + lll->latency_event;
 
 	/* Update BIS packet counter to next value */
-	lll->payload_count += (lll->latency_prepare * lll->bn);
+	lll->payload_count += (lll->latency_event + 1U) * lll->bn;
 
 	/* Reset accumulated latencies */
 	lll->latency_prepare = 0U;
 
+	/* Accumulate window widening */
+	lll->window_widening_prepare_us += lll->window_widening_periodic_us *
+					   (lll->lazy_prepare + 1U);
+	if (lll->window_widening_prepare_us > lll->window_widening_max_us) {
+		lll->window_widening_prepare_us = lll->window_widening_max_us;
+	}
+
 	/* Current window widening */
 	lll->window_widening_event_us += lll->window_widening_prepare_us;
 	lll->window_widening_prepare_us = 0U;
@@ -476,6 +445,7 @@ static int is_abort_cb(void *next, void *curr, lll_prepare_cb_t *resume_cb)
 static void abort_cb(struct lll_prepare_param *prepare_param, void *param)
 {
 	struct event_done_extra *e;
+	struct lll_sync_iso *lll;
 	int err;
 
 	/* NOTE: This is not a prepare being cancelled */
@@ -484,7 +454,7 @@ static void abort_cb(struct lll_prepare_param *prepare_param, void *param)
 		radio_disable();
 
 		if (IS_ENABLED(CONFIG_BT_CTLR_BROADCAST_ISO_ENC)) {
-			const struct lll_sync_iso *lll = param;
+			lll = param;
 
 			if (lll->enc) {
 				radio_ccm_disable();
@@ -500,6 +470,20 @@ static void abort_cb(struct lll_prepare_param *prepare_param, void *param)
 	err = lll_hfclock_off();
 	LL_ASSERT(err >= 0);
 
+	/* Get reference to LLL connection context */
+	lll = prepare_param->param;
+
+	/* Accumulate the latency as event is aborted while being in pipeline */
+	lll->lazy_prepare = prepare_param->lazy;
+	lll->latency_prepare += (lll->lazy_prepare + 1U);
+
+	/* Accumulate window widening */
+	lll->window_widening_prepare_us += lll->window_widening_periodic_us *
+					   (prepare_param->lazy + 1);
+	if (lll->window_widening_prepare_us > lll->window_widening_max_us) {
+		lll->window_widening_prepare_us = lll->window_widening_max_us;
+	}
+
 	/* Extra done event, to check sync lost */
 	e = ull_event_done_extra_get();
 	LL_ASSERT(e);

subsys/bluetooth/controller/ll_sw/ull_conn.c

@@ -1129,7 +1129,7 @@ void ull_conn_done(struct node_rx_event_done *done)
 #endif /* CONFIG_BT_PERIPHERAL */
 	}
 
-	elapsed_event = latency_event + lll->lazy_prepare + 1U;
+	elapsed_event = lll->lazy_prepare + 1U;
 
 	/* Reset supervision countdown */
 	if (done->extra.crc_valid && !done->extra.is_aborted) {

subsys/bluetooth/controller/ll_sw/ull_sync.c

@@ -1342,7 +1342,7 @@ void ull_sync_done(struct node_rx_event_done *done)
 			sync->sync_expire = 0U;
 		}
 
-		elapsed_event = skip_event + lll->lazy_prepare + 1U;
+		elapsed_event = lll->lazy_prepare + 1U;
 
 		/* Reset supervision countdown */
 		if (done->extra.crc_valid) {

subsys/bluetooth/controller/ll_sw/ull_sync_iso.c

@@ -185,6 +185,7 @@ uint8_t ll_big_sync_create(uint8_t big_handle, uint16_t sync_handle,
 
 	/* Initialize sync LLL context */
 	lll = &sync_iso->lll;
+	lll->lazy_prepare = 0U;
 	lll->latency_prepare = 0U;
 	lll->latency_event = 0U;
 	lll->window_widening_prepare_us = 0U;
@@ -762,11 +763,6 @@ void ull_sync_iso_done(struct node_rx_event_done *done)
 
 	/* Events elapsed used in timeout checks below */
 	latency_event = lll->latency_event;
-	if (lll->latency_prepare) {
-		elapsed_event = latency_event + lll->latency_prepare;
-	} else {
-		elapsed_event = latency_event + 1U;
-	}
 
 	/* Check for establishmet failure */
 	if (done->extra.estab_failed) {
@@ -800,6 +796,8 @@ void ull_sync_iso_done(struct node_rx_event_done *done)
 		}
 	}
 
+	elapsed_event = lll->lazy_prepare + 1U;
+
 	/* check timeout */
 	force = 0U;
 	if (sync_iso->timeout_expire) {