Bluetooth: Controller: Separate Tx/Rx frame spacing

subsys/bluetooth/controller/Kconfig.ll_sw_split

@@ -900,6 +900,13 @@ config BT_CTLR_RADIO_ENABLE_FAST
 	help
 	  Enable use of fast radio ramp-up mode.
 
+config BT_CTLR_RADIO_TIMER_ISR
+	# Hidden, enables use of timer ISR callback
+	bool
+	depends on SOC_COMPATIBLE_NRF52X || SOC_COMPATIBLE_NRF53X
+	help
+	  Enables use of timer ISR callback.
+
 config BT_CTLR_TIFS_HW
 	bool "H/w Accelerated tIFS Trx switching"
 	depends on !BT_CTLR_RADIO_ENABLE_FAST && BT_CTLR_TIFS_HW_SUPPORT
@@ -1013,6 +1020,14 @@ config BT_CTLR_TX_RETRY_DISABLE
 	  would happen in the next connection event instead of repeated retries
 	  in the current connection event.
 
+config BT_CTLR_TX_DEFER
+	bool "Deferred ACL Tx packet transmission setup"
+	select BT_CTLR_RADIO_TIMER_ISR
+	help
+	  Enable deferred ACL Tx packet transmission setup by radio, so that an
+	  enqueued ACL Data packet by the upper layer can be transmitted with
+	  the shortest latency.
+
 config BT_CTLR_THROUGHPUT
 	bool "Measure incoming Tx throughput"
 	help
@@ -1073,6 +1088,19 @@ config BT_CTLR_ALLOW_SAME_PEER_CONN
 	  WARNING: This option enables behavior that violates the Bluetooth
 	  specification.
 
+config BT_CTLR_CONN_INTERVAL_LOW_LATENCY
+	bool "Allow low latency connection intervals"
+	help
+	  Allow low latency connection intervals.
+
+config BT_CTLR_EVENT_IFS_LOW_LAT_US
+	prompt "Low latency tIFS value in microseconds" if BT_CTLR_CONN_INTERVAL_LOW_LATENCY
+	int
+	default 52 if BT_CTLR_CONN_INTERVAL_LOW_LATENCY
+	default 150
+	help
+	  Set low latency tIFS value.
+
 endif # BT_CONN
 
 config BT_CTLR_ADV_INDICATION

subsys/bluetooth/controller/ll_sw/lll.h

@@ -16,11 +16,12 @@
 
 #define EVENT_PIPELINE_MAX 7
 
-#define ADV_INT_UNIT_US      625U
-#define SCAN_INT_UNIT_US     625U
-#define CONN_INT_UNIT_US     1250U
-#define ISO_INT_UNIT_US      CONN_INT_UNIT_US
-#define PERIODIC_INT_UNIT_US CONN_INT_UNIT_US
+#define ADV_INT_UNIT_US          625U
+#define SCAN_INT_UNIT_US         625U
+#define CONN_INT_UNIT_US         1250U
+#define ISO_INT_UNIT_US          CONN_INT_UNIT_US
+#define PERIODIC_INT_UNIT_US     CONN_INT_UNIT_US
+#define CONN_LOW_LAT_INT_UNIT_US 500U
 
 #define ISO_INTERVAL_TO_US(interval) ((interval) * ISO_INT_UNIT_US)
 

subsys/bluetooth/controller/ll_sw/lll_conn.h

@@ -43,10 +43,15 @@
 	uint8_t access_addr[4];
 	uint8_t crc_init[3];
 
+	uint16_t tifs_tx_us;
+	uint16_t tifs_rx_us;
+	uint16_t tifs_hcto_us;
+	uint16_t tifs_cis_us;
+
 	uint16_t handle;
 	uint16_t interval;
-	uint16_t latency;
 
+	uint16_t latency;
 	uint16_t latency_prepare;
 	uint16_t lazy_prepare;
 	uint16_t latency_event;
@@ -170,8 +175,11 @@
 void lll_conn_flush(uint16_t handle, struct lll_conn *lll);
 
 void lll_conn_prepare_reset(void);
-int lll_conn_is_abort_cb(void *next, void *curr, lll_prepare_cb_t *resume_cb);
+int lll_conn_central_is_abort_cb(void *next, void *curr,
+				 lll_prepare_cb_t *resume_cb);
+int lll_conn_peripheral_is_abort_cb(void *next, void *curr,
+				    lll_prepare_cb_t *resume_cb);
 void lll_conn_abort_cb(struct lll_prepare_param *prepare_param, void *param);
 void lll_conn_isr_rx(void *param);
 void lll_conn_isr_tx(void *param);
 void lll_conn_rx_pkt_set(struct lll_conn *lll);

subsys/bluetooth/controller/ll_sw/lll_conn_iso.h

@@ -36,6 +36,11 @@ struct lll_conn_iso_stream {
 	uint32_t offset;            /* Offset of CIS from start of CIG in us */
 	uint32_t sub_interval;      /* Interval between subevents in us */
 	uint8_t  nse:5;             /* Number of subevents */
+
+	/* Frame Spacing */
+	uint16_t tifs_us;
+
+	/* Stream parameters */
 	struct lll_conn_iso_stream_rxtx rx; /* RX parameters */
 	struct lll_conn_iso_stream_rxtx tx; /* TX parameters */
 

subsys/bluetooth/controller/ll_sw/nordic/hal/nrf5/radio/radio.c

@@ -620,7 +620,7 @@
 		 * Note: this depends on the function being called exactly once
 		 * in the ISR function.
 		 */
-		last_pdu_end_us += EVENT_TIMER->CC[2];
+		last_pdu_end_us += EVENT_TIMER->CC[HAL_EVENT_TIMER_TRX_END_CC_OFFSET];
 		return 1;
 	} else {
 		return 0;
@@ -1153,6 +1153,56 @@
 	return (NRF_RADIO->EVENTS_BCMATCH != 0);
 }
 
+#if defined(CONFIG_BT_CTLR_RADIO_TIMER_ISR)
+static radio_isr_cb_t isr_radio_tmr_cb;
+static void           *isr_radio_tmr_cb_param;
+
+void isr_radio_tmr(void)
+{
+	irq_disable(TIMER0_IRQn);
+	nrf_timer_int_disable(EVENT_TIMER, TIMER_INTENSET_COMPARE2_Msk);
+	nrf_timer_event_clear(EVENT_TIMER, HAL_EVENT_TIMER_DEFERRED_TX_EVENT);
+
+	isr_radio_tmr_cb(isr_radio_tmr_cb_param);
+}
+
+uint32_t radio_tmr_isr_set(uint32_t start_us, radio_isr_cb_t cb, void *param)
+{
+	irq_disable(TIMER0_IRQn);
+
+	isr_radio_tmr_cb_param = param;
+	isr_radio_tmr_cb = cb;
+
+	/* start_us could be the current count in the timer */
+	uint32_t now_us = start_us;
+
+	/* Setup timer compare while determining the latency in doing so */
+	do {
+		/* Set start to be, now plus the determined latency */
+		start_us = (now_us << 1) - start_us;
+
+		/* Setup compare event with min. 1 us offset */
+		nrf_timer_event_clear(EVENT_TIMER, HAL_EVENT_TIMER_DEFERRED_TX_EVENT);
+		nrf_timer_cc_set(EVENT_TIMER, HAL_EVENT_TIMER_DEFERRED_TRX_CC_OFFSET,
+				 start_us + 1U);
+
+		/* Capture the current time */
+		nrf_timer_task_trigger(EVENT_TIMER, HAL_EVENT_TIMER_SAMPLE_TASK);
+
+		now_us = EVENT_TIMER->CC[HAL_EVENT_TIMER_SAMPLE_CC_OFFSET];
+	} while ((now_us > start_us) &&
+		 (EVENT_TIMER->EVENTS_COMPARE[HAL_EVENT_TIMER_DEFERRED_TRX_CC_OFFSET] == 0U));
+
+	nrf_timer_int_enable(EVENT_TIMER, TIMER_INTENSET_COMPARE2_Msk);
+
+	NVIC_ClearPendingIRQ(TIMER0_IRQn);
+
+	irq_enable(TIMER0_IRQn);
+
+	return start_us + 1U;
+}
+#endif /* CONFIG_BT_CTLR_RADIO_TIMER_ISR */
+
 void radio_tmr_status_reset(void)
 {
 #if defined(CONFIG_BT_CTLR_NRF_GRTC)
@@ -1362,7 +1412,7 @@
 	EVENT_TIMER->PRESCALER = HAL_EVENT_TIMER_PRESCALER_VALUE;
 	EVENT_TIMER->BITMODE = 2;	/* 24 - bit */
 
-	nrf_timer_cc_set(EVENT_TIMER, 0, remainder);
+	nrf_timer_cc_set(EVENT_TIMER, HAL_EVENT_TIMER_TRX_CC_OFFSET, remainder);
 
 #if defined(CONFIG_BT_CTLR_NRF_GRTC)
 	uint32_t cntr_l, cntr_h, cntr_h_overflow, stale;
@@ -1486,7 +1536,7 @@
 	nrf_timer_task_trigger(EVENT_TIMER, NRF_TIMER_TASK_STOP);
 	nrf_timer_task_trigger(EVENT_TIMER, NRF_TIMER_TASK_CLEAR);
 
-	nrf_timer_cc_set(EVENT_TIMER, 0, remainder_us);
+	nrf_timer_cc_set(EVENT_TIMER, HAL_EVENT_TIMER_TRX_CC_OFFSET, remainder_us);
 
 #if defined(CONFIG_BT_CTLR_NRF_GRTC)
 	uint32_t cntr_l, cntr_h, cntr_h_overflow, stale;
@@ -1602,7 +1652,7 @@
 	uint32_t now_us = start_us;
 	uint32_t actual_us;
 
-	/* Setup PPI while determining the latency in doing so */
+	/* Setup timer compare while determining the latency in doing so */
 	do {
 		/* Set start to be, now plus the determined latency */
 		start_us = (now_us << 1) - start_us;
@@ -1624,15 +1674,15 @@
 		actual_us += latency_us;
 #endif /* !CONFIG_BT_CTLR_SW_SWITCH_SINGLE_TIMER */
 
-		nrf_timer_event_clear(EVENT_TIMER, NRF_TIMER_EVENT_COMPARE0);
-		nrf_timer_cc_set(EVENT_TIMER, 0, actual_us);
+		nrf_timer_event_clear(EVENT_TIMER, HAL_EVENT_TIMER_TRX_EVENT);
+		nrf_timer_cc_set(EVENT_TIMER, HAL_EVENT_TIMER_TRX_CC_OFFSET, actual_us);
 
 		/* Capture the current time */
-		nrf_timer_task_trigger(EVENT_TIMER,
-				       HAL_EVENT_TIMER_SAMPLE_TASK);
+		nrf_timer_task_trigger(EVENT_TIMER, HAL_EVENT_TIMER_SAMPLE_TASK);
 
 		now_us = EVENT_TIMER->CC[HAL_EVENT_TIMER_SAMPLE_CC_OFFSET];
-	} while ((now_us > start_us) && (EVENT_TIMER->EVENTS_COMPARE[0] == 0U));
+	} while ((now_us > start_us) &&
+		 (EVENT_TIMER->EVENTS_COMPARE[HAL_EVENT_TIMER_TRX_CC_OFFSET] == 0U));
 
 	return actual_us;
 }
@@ -1688,7 +1738,7 @@
 
 void radio_tmr_hcto_configure(uint32_t hcto)
 {
-	nrf_timer_cc_set(EVENT_TIMER, 1, hcto);
+	nrf_timer_cc_set(EVENT_TIMER, HAL_EVENT_TIMER_HCTO_CC_OFFSET, hcto);
 
 	hal_radio_recv_timeout_cancel_ppi_config();
 	hal_radio_disable_on_hcto_ppi_config();
@@ -1708,7 +1758,7 @@
 
 uint32_t radio_tmr_aa_get(void)
 {
-	return EVENT_TIMER->CC[1];
+	return EVENT_TIMER->CC[HAL_EVENT_TIMER_HCTO_CC_OFFSET];
 }
 
 static uint32_t radio_tmr_aa;
@@ -1726,7 +1776,7 @@
 
 uint32_t radio_tmr_ready_get(void)
 {
-	return EVENT_TIMER->CC[0];
+	return EVENT_TIMER->CC[HAL_EVENT_TIMER_TRX_CC_OFFSET];
 }
 
 static uint32_t radio_tmr_ready;
@@ -1765,7 +1815,7 @@
 #if defined(CONFIG_BT_CTLR_SW_SWITCH_SINGLE_TIMER)
 	return last_pdu_end_us;
 #else /* !CONFIG_BT_CTLR_SW_SWITCH_SINGLE_TIMER */
-	return EVENT_TIMER->CC[2];
+	return EVENT_TIMER->CC[HAL_EVENT_TIMER_TRX_END_CC_OFFSET];
 #endif /* !CONFIG_BT_CTLR_SW_SWITCH_SINGLE_TIMER */
 }
 
@@ -1909,9 +1959,10 @@
 
 void radio_gpio_pa_lna_enable(uint32_t trx_us)
 {
-	nrf_timer_cc_set(EVENT_TIMER, 2, trx_us);
+	nrf_timer_cc_set(EVENT_TIMER, HAL_EVENT_TIMER_PA_LNA_CC_OFFSET, trx_us);
 #if defined(HAL_RADIO_FEM_IS_NRF21540) && DT_NODE_HAS_PROP(FEM_NODE, pdn_gpios)
-	nrf_timer_cc_set(EVENT_TIMER, 3, (trx_us - NRF_GPIO_PDN_OFFSET));
+	nrf_timer_cc_set(EVENT_TIMER, HAL_EVENT_TIMER_PA_LNA_PDN_CC_OFFSET,
+			 (trx_us - NRF_GPIO_PDN_OFFSET));
 	hal_radio_nrf_ppi_channels_enable(BIT(HAL_ENABLE_PALNA_PPI) |
 					  BIT(HAL_DISABLE_PALNA_PPI) |
 					  BIT(HAL_ENABLE_FEM_PPI) |

subsys/bluetooth/controller/ll_sw/nordic/hal/nrf5/radio/radio.h

@@ -130,6 +130,9 @@ void radio_bc_configure(uint32_t n);
 void radio_bc_status_reset(void);
 uint32_t radio_bc_has_match(void);
 
+void isr_radio_tmr(void);
+uint32_t radio_tmr_isr_set(uint32_t start_us, radio_isr_cb_t cb, void *param);
+
 void radio_tmr_status_reset(void);
 void radio_tmr_tx_status_reset(void);
 void radio_tmr_rx_status_reset(void);

subsys/bluetooth/controller/ll_sw/nordic/hal/nrf5/radio/radio_nrf5.h

@@ -109,3 +109,6 @@
 #else /* For simulated targets there is no delay for the PPI task -> TIMER start */
 #define HAL_RADIO_TMR_START_DELAY_US 0U
 #endif
+
+/* This is the minimum prepare duration required to setup radio for deferred transmission */
+#define HAL_RADIO_TMR_DEFERRED_TX_DELAY_US 50U

subsys/bluetooth/controller/ll_sw/nordic/hal/nrf5/radio/radio_nrf5_resources.h

@@ -25,9 +25,21 @@
  */
 #define NRF_RADIO_SHORTS_TRX_END_DISABLE_Msk HAL_RADIO_SHORTS_TRX_END_DISABLE_Msk
 
-#define HAL_EVENT_TIMER_SAMPLE_CC_OFFSET 3
-#define HAL_EVENT_TIMER_SAMPLE_TASK NRF_TIMER_TASK_CAPTURE3
+#define HAL_EVENT_TIMER_TRX_CC_OFFSET          0
+#define HAL_EVENT_TIMER_TRX_EVENT              NRF_TIMER_EVENT_COMPARE0
+
+#define HAL_EVENT_TIMER_HCTO_CC_OFFSET         1
+#define HAL_EVENT_TIMER_TRX_END_CC_OFFSET      2
+
+#define HAL_EVENT_TIMER_DEFERRED_TRX_CC_OFFSET 2
+#define HAL_EVENT_TIMER_DEFERRED_TX_EVENT      NRF_TIMER_EVENT_COMPARE2
+
+#define HAL_EVENT_TIMER_SAMPLE_CC_OFFSET       3
+#define HAL_EVENT_TIMER_SAMPLE_TASK            NRF_TIMER_TASK_CAPTURE3
+
+#define HAL_EVENT_TIMER_PA_LNA_CC_OFFSET       2
+#define HAL_EVENT_TIMER_PA_LNA_PDN_CC_OFFSET   3
 
 #else /* !CONFIG_BT_CTLR_TIFS_HW */
 #if defined(CONFIG_BT_CTLR_SW_SWITCH_SINGLE_TIMER)
 #define EVENT_TIMER_ID 4
@@ -56,9 +68,21 @@
  */
 #define NRF_RADIO_SHORTS_TRX_END_DISABLE_Msk HAL_RADIO_SHORTS_TRX_END_DISABLE_Msk
 
-#define HAL_EVENT_TIMER_SAMPLE_CC_OFFSET 2
-#define HAL_EVENT_TIMER_SAMPLE_TASK NRF_TIMER_TASK_CAPTURE2
+#define HAL_EVENT_TIMER_TRX_CC_OFFSET          0
+#define HAL_EVENT_TIMER_TRX_EVENT              NRF_TIMER_EVENT_COMPARE0
+
+#define HAL_EVENT_TIMER_HCTO_CC_OFFSET         1
+#define HAL_EVENT_TIMER_TRX_END_CC_OFFSET      2
+
+#define HAL_EVENT_TIMER_DEFERRED_TRX_CC_OFFSET 2
+#define HAL_EVENT_TIMER_DEFERRED_TX_EVENT      NRF_TIMER_EVENT_COMPARE2
+
+#define HAL_EVENT_TIMER_SAMPLE_CC_OFFSET       2
+#define HAL_EVENT_TIMER_SAMPLE_TASK            NRF_TIMER_TASK_CAPTURE2
+
+#define HAL_EVENT_TIMER_PA_LNA_CC_OFFSET       2
+#define HAL_EVENT_TIMER_PA_LNA_PDN_CC_OFFSET   3
 
 #else /* !CONFIG_BT_CTLR_PHY_CODED */
 #define SW_SWITCH_TIMER_EVTS_COMP_BASE 4
 
@@ -73,9 +97,21 @@
  */
 #define NRF_RADIO_SHORTS_TRX_END_DISABLE_Msk HAL_RADIO_SHORTS_TRX_END_DISABLE_Msk
 
-#define HAL_EVENT_TIMER_SAMPLE_CC_OFFSET 3
-#define HAL_EVENT_TIMER_SAMPLE_TASK NRF_TIMER_TASK_CAPTURE3
+#define HAL_EVENT_TIMER_TRX_CC_OFFSET          0
+#define HAL_EVENT_TIMER_TRX_EVENT              NRF_TIMER_EVENT_COMPARE0
+
+#define HAL_EVENT_TIMER_HCTO_CC_OFFSET         1
+#define HAL_EVENT_TIMER_TRX_END_CC_OFFSET      2
+
+#define HAL_EVENT_TIMER_DEFERRED_TRX_CC_OFFSET 2
+#define HAL_EVENT_TIMER_DEFERRED_TX_EVENT      NRF_TIMER_EVENT_COMPARE2
+
+#define HAL_EVENT_TIMER_SAMPLE_CC_OFFSET       3
+#define HAL_EVENT_TIMER_SAMPLE_TASK            NRF_TIMER_TASK_CAPTURE3
+
+#define HAL_EVENT_TIMER_PA_LNA_CC_OFFSET       2
+#define HAL_EVENT_TIMER_PA_LNA_PDN_CC_OFFSET   3
 #endif /* !CONFIG_BT_CTLR_PHY_CODED */
 
 #else /* !CONFIG_BT_CTLR_SW_SWITCH_SINGLE_TIMER */
 #define EVENT_TIMER_ID 0
@@ -142,7 +178,19 @@
 #define NRF_RADIO_SHORTS_TRX_END_DISABLE_Msk HAL_RADIO_SHORTS_TRX_END_DISABLE_Msk
 #endif /* !CONFIG_BT_CTLR_DF */
 
-#define HAL_EVENT_TIMER_SAMPLE_CC_OFFSET 3
-#define HAL_EVENT_TIMER_SAMPLE_TASK NRF_TIMER_TASK_CAPTURE3
+#define HAL_EVENT_TIMER_TRX_CC_OFFSET          0
+#define HAL_EVENT_TIMER_TRX_EVENT              NRF_TIMER_EVENT_COMPARE0
+
+#define HAL_EVENT_TIMER_HCTO_CC_OFFSET         1
+#define HAL_EVENT_TIMER_TRX_END_CC_OFFSET      2
+
+#define HAL_EVENT_TIMER_DEFERRED_TRX_CC_OFFSET 2
+#define HAL_EVENT_TIMER_DEFERRED_TX_EVENT      NRF_TIMER_EVENT_COMPARE2
+
+#define HAL_EVENT_TIMER_SAMPLE_CC_OFFSET       3
+#define HAL_EVENT_TIMER_SAMPLE_TASK            NRF_TIMER_TASK_CAPTURE3
+
+#define HAL_EVENT_TIMER_PA_LNA_CC_OFFSET       2
+#define HAL_EVENT_TIMER_PA_LNA_PDN_CC_OFFSET   3
 #endif /* !CONFIG_BT_CTLR_SW_SWITCH_SINGLE_TIMER */
 #endif /* !CONFIG_BT_CTLR_TIFS_HW */