Bluetooth: controller: Implement ADV re-schedule for new scheduler

The new JIT scheduler does not have slot reservation, which means that
the ticker extension feature for automatically re-scheduling a colliding
non-anchored event, e.g. ADV, cannot be used.

This implementaion reacts to ADV envent done with result ABORTED or
TOO_LATE, and in those cases attempts to re-schedule the ADV event again
within the 10 ms pertubation window.

As the original scheduling, the re-scheduling is randomized, so there
is no absolute predictability as to how many attempts will be made. The
advertiser will attempt with randomly delayed re-schdules until the
window is exhausted.

If re-scheduling is unsuccessful, the weight of the ADV event is
increased, improving it's chances of success in the next event.

Signed-off-by: Morten Priess <[email protected]>

Author: mtpr-ot

subsys/bluetooth/controller/ll_sw/lll.h

@@ -134,6 +134,12 @@ enum {
 
 #define TICKER_ID_ULL_BASE ((TICKER_ID_LLL_PREEMPT) + 1)
 
+enum done_result {
+	DONE_COMPLETED,
+	DONE_ABORTED,
+	DONE_LATE
+};
+
 struct ull_hdr {
 	uint8_t volatile ref;  /* Number of ongoing (between Prepare and Done)
 				* events
@@ -331,11 +337,11 @@ enum {
 	EVENT_DONE_EXTRA_TYPE_CONN,
 #endif /* CONFIG_BT_CONN */
 
-#if defined(CONFIG_BT_CTLR_ADV_EXT)
+#if defined(CONFIG_BT_CTLR_ADV_EXT) || defined(CONFIG_BT_CTLR_JIT_SCHEDULING)
 #if defined(CONFIG_BT_BROADCASTER)
 	EVENT_DONE_EXTRA_TYPE_ADV,
 #endif /* CONFIG_BT_BROADCASTER */
-#endif /* CONFIG_BT_CTLR_ADV_EXT */
+#endif /* CONFIG_BT_CTLR_ADV_EXT || CONFIG_BT_CTLR_JIT_SCHEDULING */
 
 #if defined(CONFIG_BT_OBSERVER)
 #if defined(CONFIG_BT_CTLR_ADV_EXT)
@@ -368,6 +374,9 @@ struct event_done_extra_drift {
 
 struct event_done_extra {
 	uint8_t type;
+#if defined(CONFIG_BT_CTLR_JIT_SCHEDULING)
+	uint8_t result;
+#endif /* CONFIG_BT_CTLR_JIT_SCHEDULING */
 	union {
 		struct {
 			uint16_t trx_cnt;
@@ -402,7 +411,7 @@ static inline void lll_hdr_init(void *lll, void *parent)
 #endif /* CONFIG_BT_CTLR_JIT_SCHEDULING */
 }
 
-void lll_done_score(void *param, uint8_t too_late, uint8_t aborted);
+void lll_done_score(void *param, uint8_t result);
 
 int lll_init(void);
 int lll_reset(void);

subsys/bluetooth/controller/ll_sw/lll_common.c

@@ -80,15 +80,15 @@ void lll_resume(void *param)
 }
 
 #if defined(CONFIG_BT_CTLR_JIT_SCHEDULING)
-void lll_done_score(void *param, uint8_t too_late, uint8_t aborted)
+void lll_done_score(void *param, uint8_t result)
 {
 	struct lll_hdr *hdr = param;
 
 	if (!hdr) {
 		return;
 	}
 
-	if (!too_late && !aborted) {
+	if (result == DONE_COMPLETED) {
 		hdr->score  = 0;
 		hdr->latency = 0;
 	} else {

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

@@ -344,7 +344,19 @@ int lll_done(void *param)
 #endif /* !CONFIG_BT_CTLR_LOW_LAT_ULL_DONE */
 
 #if defined(CONFIG_BT_CTLR_JIT_SCHEDULING)
-	lll_done_score(param, 0, 0); /* TODO */
+	struct event_done_extra *extra;
+	uint8_t result;
+
+	/* TODO: Pass from calling function */
+	result = DONE_COMPLETED;
+
+	lll_done_score(param, result);
+
+	extra = ull_event_done_extra_get();
+	LL_ASSERT(extra);
+
+	/* Set result in done extra data - type was set by the role */
+	extra->result = result;
 #endif /* CONFIG_BT_CTLR_JIT_SCHEDULING */
 
 	/* Let ULL know about LLL event done */

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

@@ -45,6 +45,8 @@
 #include "lll_prof_internal.h"
 #include "lll_df_internal.h"
 
+#include "ull_internal.h"
+
 #define BT_DBG_ENABLED IS_ENABLED(CONFIG_BT_DEBUG_HCI_DRIVER)
 #define LOG_MODULE_NAME bt_ctlr_lll_adv
 #include "common/log.h"
@@ -1209,14 +1211,9 @@ static void isr_done(void *param)
 	}
 #endif /* CONFIG_BT_CTLR_ADV_INDICATION */
 
-#if defined(CONFIG_BT_CTLR_ADV_EXT)
-	struct event_done_extra *extra;
-
-	extra = ull_event_done_extra_get();
-	LL_ASSERT(extra);
-
-	extra->type = EVENT_DONE_EXTRA_TYPE_ADV;
-#endif  /* CONFIG_BT_CTLR_ADV_EXT */
+#if defined(CONFIG_BT_CTLR_ADV_EXT) || defined(CONFIG_BT_CTLR_JIT_SCHEDULING)
+	ull_done_extra_type_set(EVENT_DONE_EXTRA_TYPE_ADV);
+#endif /* CONFIG_BT_CTLR_ADV_EXT || CONFIG_BT_CTLR_JIT_SCHEDULING */
 
 	lll_isr_cleanup(param);
 }

subsys/bluetooth/controller/ll_sw/ull.c

@@ -2484,13 +2484,16 @@ static inline void rx_demux_event_done(memq_link_t *link,
 		break;
 #endif /* CONFIG_BT_CONN */
 
-#if defined(CONFIG_BT_CTLR_ADV_EXT)
 #if defined(CONFIG_BT_BROADCASTER)
+#if defined(CONFIG_BT_CTLR_ADV_EXT) || \
+	defined(CONFIG_BT_CTLR_JIT_SCHEDULING)
 	case EVENT_DONE_EXTRA_TYPE_ADV:
 		ull_adv_done(done);
 		break;
+#endif /* CONFIG_BT_CTLR_ADV_EXT || CONFIG_BT_CTLR_JIT_SCHEDULING */
 #endif /* CONFIG_BT_BROADCASTER */
 
+#if defined(CONFIG_BT_CTLR_ADV_EXT)
 #if defined(CONFIG_BT_OBSERVER)
 	case EVENT_DONE_EXTRA_TYPE_SCAN:
 		ull_scan_done(done);
@@ -2553,3 +2556,15 @@ static void disabled_cb(void *param)
 {
 	k_sem_give(param);
 }
+
+struct event_done_extra *ull_done_extra_type_set(uint8_t type)
+{
+	struct event_done_extra *extra;
+
+	extra = ull_event_done_extra_get();
+	LL_ASSERT(extra);
+
+	extra->type = type;
+
+	return extra;
+}

subsys/bluetooth/controller/ll_sw/ull_adv.c

@@ -16,6 +16,7 @@
 #include "hal/ccm.h"
 #include "hal/radio.h"
 #include "hal/ticker.h"
+#include "hal/cntr.h"
 
 #include "util/util.h"
 #include "util/mem.h"
@@ -1732,20 +1733,109 @@ uint8_t ull_scan_rsp_set(struct ll_adv_set *adv, uint8_t len,
 	return 0;
 }
 
-#if defined(CONFIG_BT_CTLR_ADV_EXT)
+static uint32_t ticker_update_rand(struct ll_adv_set *adv, uint32_t ticks_delay_window,
+				   uint32_t ticks_delay_window_offset,
+				   uint32_t ticks_adjust_minus)
+{
+	uint32_t random_delay;
+	uint32_t ret;
+
+	/* Get pseudo-random number in the range [0..ticks_delay_window].
+	 * Please note that using modulo of 2^32 samle space has an uneven
+	 * distribution, slightly favoring smaller values.
+	 */
+	lll_rand_isr_get(&random_delay, sizeof(random_delay));
+	random_delay %= ticks_delay_window;
+	random_delay += (ticks_delay_window_offset + 1);
+
+	ret = ticker_update(TICKER_INSTANCE_ID_CTLR,
+			    TICKER_USER_ID_ULL_HIGH,
+			    TICKER_ID_ADV_BASE + ull_adv_handle_get(adv),
+			    random_delay,
+			    ticks_adjust_minus, 0, 0, 0, 0,
+			    ticker_op_update_cb, adv);
+
+	LL_ASSERT((ret == TICKER_STATUS_SUCCESS) ||
+		  (ret == TICKER_STATUS_BUSY));
+
+#if defined(CONFIG_BT_CTLR_JIT_SCHEDULING)
+	adv->delay = random_delay;
+#endif
+	return random_delay;
+}
+
+#if defined(CONFIG_BT_CTLR_ADV_EXT) || \
+	defined(CONFIG_BT_CTLR_JIT_SCHEDULING)
 void ull_adv_done(struct node_rx_event_done *done)
 {
+#if defined(CONFIG_BT_CTLR_ADV_EXT)
 	struct lll_adv_aux *lll_aux;
 	struct node_rx_hdr *rx_hdr;
-	struct ll_adv_set *adv;
-	struct lll_adv *lll;
 	uint8_t handle;
 	uint32_t ret;
+#endif /* CONFIG_BT_CTLR_ADV_EXT */
+	struct ll_adv_set *adv;
+	struct lll_adv *lll;
 
 	/* Get reference to ULL context */
 	adv = CONTAINER_OF(done->param, struct ll_adv_set, ull);
 	lll = &adv->lll;
 
+#if defined(CONFIG_BT_CTLR_JIT_SCHEDULING)
+	if (done->extra.result == DONE_COMPLETED) {
+		/* Event completed successfully */
+		adv->delay_remain = ULL_ADV_RANDOM_DELAY;
+	} else {
+		/* Event aborted or too late - try to re-schedule */
+		uint32_t ticks_elapsed;
+		uint32_t ticks_now;
+
+		const uint32_t prepare_overhead =
+			HAL_TICKER_US_TO_TICKS(EVENT_OVERHEAD_START_US);
+		const uint32_t ticks_adv_airtime = adv->ticks_at_expire +
+			prepare_overhead;
+
+		ticks_elapsed = 0;
+
+		ticks_now = cntr_cnt_get();
+		if ((int32_t)(ticks_now - ticks_adv_airtime) > 0) {
+			ticks_elapsed = ticks_now - ticks_adv_airtime;
+		}
+
+		if (adv->delay_remain >= adv->delay + ticks_elapsed) {
+			/* The perturbation window is still open */
+			adv->delay_remain -= (adv->delay + ticks_elapsed);
+		} else {
+			adv->delay_remain = 0;
+		}
+
+		/* Check if we have enough time to re-schedule */
+		if (adv->delay_remain > prepare_overhead) {
+			uint32_t ticks_adjust_minus;
+
+			/* Get negative ticker adjustment needed to pull back ADV one
+			 * interval plus the randomized delay. This means that the ticker
+			 * will be updated to expire in time frame of now + start
+			 * overhead, until 10 ms window is exhausted.
+			 */
+			ticks_adjust_minus = HAL_TICKER_US_TO_TICKS(
+				(uint64_t)adv->interval * ADV_INT_UNIT_US) + adv->delay;
+
+			/* Apply random delay in range [prepare_overhead..delay_remain] */
+			ticker_update_rand(adv, adv->delay_remain - prepare_overhead,
+					   prepare_overhead, ticks_adjust_minus);
+
+			/* Score of the event was increased due to the result, but since
+			 * we're getting a another chance we'll set it back.
+			 */
+			adv->lll.hdr.score -= 1;
+		} else {
+			adv->delay_remain = ULL_ADV_RANDOM_DELAY;
+		}
+	}
+#endif /* CONFIG_BT_CTLR_JIT_SCHEDULING */
+
+#if defined(CONFIG_BT_CTLR_ADV_EXT)
 	if (adv->max_events && (adv->event_counter >= adv->max_events)) {
 		adv->max_events = 0;
 
@@ -1791,8 +1881,9 @@ void ull_adv_done(struct node_rx_event_done *done)
 
 	LL_ASSERT((ret == TICKER_STATUS_SUCCESS) ||
 		  (ret == TICKER_STATUS_BUSY));
-}
 #endif /* CONFIG_BT_CTLR_ADV_EXT */
+}
+#endif /* CONFIG_BT_CTLR_ADV_EXT || CONFIG_BT_CTLR_JIT_SCHEDULING */
 
 const uint8_t *ull_adv_pdu_update_addrs(struct ll_adv_set *adv,
 					struct pdu_adv *pdu)
@@ -1971,6 +2062,7 @@ static void ticker_cb(uint32_t ticks_at_expire, uint32_t remainder, uint16_t laz
 	static struct mayfly mfy = {0, 0, &link, NULL, lll_adv_prepare};
 	static struct lll_prepare_param p;
 	struct ll_adv_set *adv = param;
+	uint32_t random_delay;
 	struct lll_adv *lll;
 	uint32_t ret;
 	uint8_t ref;
@@ -1997,29 +2089,19 @@ static void ticker_cb(uint32_t ticks_at_expire, uint32_t remainder, uint16_t laz
 		ret = mayfly_enqueue(TICKER_USER_ID_ULL_HIGH,
 				     TICKER_USER_ID_LLL, 0, &mfy);
 		LL_ASSERT(!ret);
+
+#if defined(CONFIG_BT_CTLR_JIT_SCHEDULING)
+		adv->ticks_at_expire = ticks_at_expire;
+#endif /* CONFIG_BT_CTLR_JIT_SCHEDULING */
 	}
 
 	/* Apply adv random delay */
 #if defined(CONFIG_BT_PERIPHERAL)
 	if (!lll->is_hdcd)
 #endif /* CONFIG_BT_PERIPHERAL */
 	{
-		uint32_t random_delay;
-		uint32_t ret;
-
-		lll_rand_isr_get(&random_delay, sizeof(random_delay));
-		random_delay %= ULL_ADV_RANDOM_DELAY;
-		random_delay += 1;
-
-		ret = ticker_update(TICKER_INSTANCE_ID_CTLR,
-				    TICKER_USER_ID_ULL_HIGH,
-				    (TICKER_ID_ADV_BASE +
-				     ull_adv_handle_get(adv)),
-				    random_delay,
-				    0, 0, 0, 0, 0,
-				    ticker_op_update_cb, adv);
-		LL_ASSERT((ret == TICKER_STATUS_SUCCESS) ||
-			  (ret == TICKER_STATUS_BUSY));
+		/* Apply random delay in range [0..ULL_ADV_RANDOM_DELAY] */
+		random_delay = ticker_update_rand(adv, ULL_ADV_RANDOM_DELAY, 0, 0);
 
 #if defined(CONFIG_BT_CTLR_ADV_EXT)
 		adv->event_counter += (lazy + 1);
@@ -2581,6 +2663,9 @@ static void init_set(struct ll_adv_set *adv)
 #endif /* CONFIG_BT_CTLR_PRIVACY */
 	adv->lll.chan_map = BT_LE_ADV_CHAN_MAP_ALL;
 	adv->lll.filter_policy = BT_LE_ADV_FP_NO_WHITELIST;
+#if defined(CONFIG_BT_CTLR_JIT_SCHEDULING)
+	adv->delay_remain = ULL_ADV_RANDOM_DELAY;
+#endif /* ONFIG_BT_CTLR_JIT_SCHEDULING */
 
 	init_pdu(lll_adv_data_peek(&ll_adv[0].lll), PDU_ADV_TYPE_ADV_IND);
 	init_pdu(lll_adv_scan_rsp_peek(&ll_adv[0].lll), PDU_ADV_TYPE_SCAN_RSP);

subsys/bluetooth/controller/ll_sw/ull_adv_types.h

@@ -57,6 +57,11 @@ struct ll_adv_set {
 #if defined(CONFIG_BT_CTLR_DF_ADV_CTE_TX)
 	struct lll_df_adv_cfg *df_cfg;
 #endif /* CONFIG_BT_CTLR_DF_ADV_CTE_TX */
+#if defined(CONFIG_BT_CTLR_JIT_SCHEDULING)
+	uint32_t delay;
+	uint32_t delay_remain;
+	uint32_t ticks_at_expire;
+#endif /* CONFIG_BT_CTLR_JIT_SCHEDULING */
 };
 
 #if defined(CONFIG_BT_CTLR_ADV_EXT)

subsys/bluetooth/controller/ll_sw/ull_internal.h

@@ -53,3 +53,4 @@ int ull_disable(void *param);
 void ull_drift_ticks_get(struct node_rx_event_done *done,
 			 uint32_t *ticks_drift_plus,
 			 uint32_t *ticks_drift_minus);
+struct event_done_extra *ull_done_extra_type_set(uint8_t type);