Bluetooth: Controller: Enable Connection Subrating support in the SDC

subsys/bluetooth/controller/Kconfig

@@ -38,6 +38,7 @@ config BT_LL_SOFTDEVICE
 	select BT_HAS_HCI_VS
 	select BT_CTLR_DF_SUPPORT if HAS_HW_NRF_RADIO_DFE
 	select BT_CTLR_LE_POWER_CONTROL_SUPPORT
+	select BT_CTLR_SUBRATING_SUPPORT
 	depends on (SOC_SERIES_BSIM_NRFXX || SOC_SERIES_NRF52X || SOC_COMPATIBLE_NRF5340_CPUNET ||\
 			    SOC_NRF54H20_CPURAD || SOC_SERIES_NRF54LX)
 	help
@@ -563,5 +564,9 @@ config BT_CTLR_SDC_CIS_SUBEVENT_LENGTH_US
 	  If this parameter is set to zero, the subevent length
 	  is chosen by the controller.
 
+config BT_CTLR_SUBRATING
+	bool "LE Connection Subrating [EXPERIMENTAL]"
+	select EXPERIMENTAL
+
 endmenu
 endif  # BT_LL_SOFTDEVICE

subsys/bluetooth/controller/hci_driver.c

@@ -175,6 +175,12 @@ BUILD_ASSERT(!IS_ENABLED(CONFIG_BT_PERIPHERAL) ||
 #define SDC_LE_POWER_CONTROL_MEM_SIZE 0
 #endif
 
+#if defined(CONFIG_BT_CTLR_SUBRATING)
+#define SDC_SUBRATING_MEM_SIZE SDC_MEM_SUBRATING(SDC_CENTRAL_COUNT + PERIPHERAL_COUNT)
+#else
+#define SDC_SUBRATING_MEM_SIZE 0
+#endif
+
 #if defined(CONFIG_BT_CTLR_CONN_ISO)
 #define SDC_MEM_CIG SDC_MEM_PER_CIG(CONFIG_BT_CTLR_CONN_ISO_GROUPS)
 #define SDC_MEM_CIS \
@@ -242,6 +248,7 @@ BUILD_ASSERT(!IS_ENABLED(CONFIG_BT_PERIPHERAL) ||
 		      (SDC_CENTRAL_COUNT * CENTRAL_MEM_SIZE) + \
 		      (SDC_ADV_SET_MEM_SIZE) + \
 		      (SDC_LE_POWER_CONTROL_MEM_SIZE) + \
+		      (SDC_SUBRATING_MEM_SIZE) + \
 		      (SDC_PERIODIC_ADV_MEM_SIZE) + \
 		      (SDC_PERIODIC_ADV_RSP_MEM_SIZE) + \
 		      (SDC_PERIODIC_SYNC_MEM_SIZE) + \
@@ -860,6 +867,21 @@ static int configure_supported_features(void)
 	}
 #endif
 
+	if (IS_ENABLED(CONFIG_BT_CTLR_SUBRATING)) {
+		if (IS_ENABLED(CONFIG_BT_CENTRAL)) {
+			err = sdc_support_connection_subrating_central();
+			if (err) {
+				return -ENOTSUP;
+			}
+		}
+		if (IS_ENABLED(CONFIG_BT_PERIPHERAL)) {
+			err = sdc_support_connection_subrating_peripheral();
+			if (err) {
+				return -ENOTSUP;
+			}
+		}
+	}
+
 	return 0;
 }
 

subsys/bluetooth/controller/hci_internal.c

@@ -65,6 +65,7 @@ static bool command_generates_command_complete_event(uint16_t hci_opcode)
 	case SDC_HCI_OPCODE_CMD_LE_CREATE_BIG:
 	case SDC_HCI_OPCODE_CMD_LE_CREATE_BIG_TEST:
 	case SDC_HCI_OPCODE_CMD_LE_TERMINATE_BIG:
+	case SDC_HCI_OPCODE_CMD_LE_SUBRATE_REQUEST:
 		return false;
 	default:
 		return true;
@@ -611,6 +612,13 @@ void hci_internal_supported_commands(sdc_hci_ip_supported_commands_t *cmds)
 #if defined(CONFIG_BT_CTLR_ISO_RX_BUFFERS)
 	cmds->hci_le_iso_receive_test = 1;
 #endif
+
+#if defined(CONFIG_BT_CTLR_SUBRATING)
+#if defined(CONFIG_BT_CENTRAL)
+	cmds->hci_le_set_default_subrate_command = 1;
+#endif
+	cmds->hci_le_subrate_request_command = 1;
+#endif /* CONFIG_BT_CTLR_SUBRATING */
 }
 
 #if defined(CONFIG_BT_HCI_VS)
@@ -785,6 +793,10 @@ void hci_internal_le_supported_features(
 #if defined(CONFIG_BT_CTLR_SDC_PAWR_SYNC)
 	features->params.periodic_advertising_with_responses_scanner = 1;
 #endif
+
+#if defined(CONFIG_BT_CTLR_SUBRATING)
+	features->params.connection_subrating = 1;
+#endif
 }
 
 static void le_read_supported_states(uint8_t *buf)
@@ -1534,6 +1546,15 @@ static uint8_t le_controller_cmd_put(uint8_t const * const cmd,
 									(void *)event_out_params);
 #endif
 
+#if defined(CONFIG_BT_CTLR_SUBRATING)
+#if defined(CONFIG_BT_CENTRAL)
+	case SDC_HCI_OPCODE_CMD_LE_SET_DEFAULT_SUBRATE:
+		return sdc_hci_cmd_le_set_default_subrate((void *)cmd_params);
+#endif
+	case SDC_HCI_OPCODE_CMD_LE_SUBRATE_REQUEST:
+		return sdc_hci_cmd_le_subrate_request((void *)cmd_params);
+#endif /* CONFIG_BT_CTLR_SUBRATING */
+
 	default:
 		return BT_HCI_ERR_UNKNOWN_CMD;
 	}