Bluetooth: Controller: Adds path loss monitoring functionality

This functionality is implemented in the HCI-facing side of the
controller and the ULL. LLL functionality is not implemented in this
commit.

Furthermore, this removes a dependency for LE Power Control, as the
features are related, but not necessarily required.

Signed-off-by: Tyler Joseph Huffman <tyhu@demant.com>

Author: tyler-huffman-demant

include/zephyr/bluetooth/hci_types.h

@@ -706,6 +706,7 @@ struct bt_hci_cp_le_set_tx_power_report_enable {
 	uint8_t  remote_enable;
 } __packed;
 
+#define BT_HCI_OP_LE_SET_PATH_LOSS_REPORTING_PARAMETERS BT_OP(BT_OGF_LE, 0x0078) /* 0x2078 */
 struct bt_hci_cp_le_set_path_loss_reporting_parameters {
 	uint16_t handle;
 	uint8_t  high_threshold;
@@ -715,17 +716,28 @@ struct bt_hci_cp_le_set_path_loss_reporting_parameters {
 	uint16_t min_time_spent;
 } __packed;
 
-struct bt_hci_cp_le_set_path_loss_reporting_enable {
+struct bt_hci_rp_le_set_path_loss_reporting_parameters {
 	uint16_t handle;
-	uint8_t  enable;
+	uint8_t  status;
 } __packed;
 
-#define BT_HCI_OP_LE_SET_PATH_LOSS_REPORTING_PARAMETERS BT_OP(BT_OGF_LE, 0x0078) /* 0x2078 */
 
 #define BT_HCI_LE_PATH_LOSS_REPORTING_DISABLE       0x00
 #define BT_HCI_LE_PATH_LOSS_REPORTING_ENABLE        0x01
 #define BT_HCI_OP_LE_SET_PATH_LOSS_REPORTING_ENABLE BT_OP(BT_OGF_LE, 0x0079) /* 0x2079 */
 
+struct bt_hci_cp_le_set_path_loss_reporting_enable {
+	uint16_t handle;
+	uint8_t  enable;
+} __packed;
+
+struct bt_hci_rp_le_set_path_loss_reporting_enable {
+	uint16_t handle;
+	uint8_t  status;
+} __packed;
+
+#define BT_HCI_OP_LE_SET_DEFAULT_SUBRATE BT_OP(BT_OGF_LE, 0x007D) /* 0x207D */
+
 struct bt_hci_cp_le_set_default_subrate {
 	uint16_t subrate_min;
 	uint16_t subrate_max;
@@ -734,6 +746,8 @@ struct bt_hci_cp_le_set_default_subrate {
 	uint16_t supervision_timeout;
 } __packed;
 
+#define BT_HCI_OP_LE_SUBRATE_REQUEST     BT_OP(BT_OGF_LE, 0x007E) /* 0x207E */
+
 struct bt_hci_cp_le_subrate_request {
 	uint16_t handle;
 	uint16_t subrate_min;
@@ -743,9 +757,6 @@ struct bt_hci_cp_le_subrate_request {
 	uint16_t supervision_timeout;
 } __packed;
 
-#define BT_HCI_OP_LE_SET_DEFAULT_SUBRATE BT_OP(BT_OGF_LE, 0x007D) /* 0x207D */
-#define BT_HCI_OP_LE_SUBRATE_REQUEST     BT_OP(BT_OGF_LE, 0x007E) /* 0x207E */
-
 #define BT_HCI_CTL_TO_HOST_FLOW_DISABLE         0x00
 #define BT_HCI_CTL_TO_HOST_FLOW_ENABLE          0x01
 #define BT_HCI_OP_SET_CTL_TO_HOST_FLOW          BT_OP(BT_OGF_BASEBAND, 0x0031) /* 0x0c31 */

subsys/bluetooth/controller/Kconfig

@@ -119,7 +119,6 @@ config BT_CTLR_LE_POWER_CONTROL_SUPPORT
 	bool
 
 config BT_CTLR_LE_PATH_LOSS_MONITORING_SUPPORT
-	depends on BT_CTLR_LE_POWER_CONTROL_SUPPORT
 	bool
 
 config BT_CTLR_SUBRATING_SUPPORT
@@ -661,7 +660,6 @@ config BT_CTLR_LE_PATH_LOSS_MONITORING
 	bool "LE Path Loss Monitoring Feature"
 	depends on BT_CTLR_LE_PATH_LOSS_MONITORING_SUPPORT
 	default y if BT_PATH_LOSS_MONITORING
-	select BT_CTLR_LE_POWER_CONTROL
 	help
 	  Enable support for LE Path Loss Monitoring feature that is defined in the
 	  Bluetooth Core specification, Version 5.4 | Vol 6, Part B, Section 4.6.32.

subsys/bluetooth/controller/hci/hci.c

@@ -2793,6 +2793,53 @@ static void le_set_phy(struct net_buf *buf, struct net_buf **evt)
 	*evt = cmd_status(status);
 }
 #endif /* CONFIG_BT_CTLR_PHY */
+
+
+#if defined(CONFIG_BT_CTLR_LE_PATH_LOSS_MONITORING)
+
+#define PATH_LOSS_FACTOR_INVALID 0xFF
+static void le_path_loss_set_parameters(struct net_buf *buf, struct net_buf **evt)
+{
+	struct bt_hci_cp_le_set_path_loss_reporting_parameters *cmd = (void *)buf->data;
+	struct bt_hci_rp_le_set_path_loss_reporting_parameters *rp;
+
+	uint16_t handle = sys_le16_to_cpu(cmd->handle);
+	uint16_t min_time_spent = sys_le16_to_cpu(cmd->min_time_spent);
+
+	rp = hci_cmd_complete(evt, sizeof(*rp));
+	rp->handle = handle;
+
+	if (cmd->high_threshold + cmd->high_hysteresis > PATH_LOSS_FACTOR_INVALID ||
+	    cmd->low_threshold < cmd->low_hysteresis                              ||
+	    cmd->low_threshold > cmd->high_threshold                              ||
+	    cmd->low_threshold + cmd->low_hysteresis > cmd->high_threshold - cmd->high_hysteresis) {
+		rp->status = BT_HCI_ERR_INVALID_PARAM;
+		return;
+	}
+
+	rp->status = ll_conn_set_path_loss_parameters(handle, cmd->high_threshold,
+						      cmd->high_hysteresis, cmd->low_threshold,
+						      cmd->low_hysteresis, min_time_spent);
+}
+
+static void le_path_loss_enable(struct net_buf *buf, struct net_buf **evt)
+{
+	struct bt_hci_cp_le_set_path_loss_reporting_enable *cmd = (void *)buf->data;
+	struct bt_hci_rp_le_set_path_loss_reporting_enable *rp;
+
+	uint16_t handle = sys_le16_to_cpu(cmd->handle);
+
+	rp = hci_cmd_complete(evt, sizeof(*rp));
+	rp->handle = handle;
+
+	/* Anything beyond 0x00 or 0x01 is reserved */
+	if (cmd->enable > 0x01) {
+		rp->status = BT_HCI_ERR_INVALID_PARAM;
+	}
+
+	rp->status = ll_conn_set_path_loss_reporting(handle, cmd->enable);
+}
+#endif /* CONFIG_BT_CTLR_LE_PATH_LOSS_MONITORING */
 #endif /* CONFIG_BT_CONN */
 
 #if defined(CONFIG_BT_CTLR_PRIVACY)
@@ -4767,6 +4814,17 @@ static int controller_cmd_handle(uint16_t  ocf, struct net_buf *cmd,
 		le_set_phy(cmd, evt);
 		break;
 #endif /* CONFIG_BT_CTLR_PHY */
+
+#if defined(CONFIG_BT_CTLR_LE_PATH_LOSS_MONITORING)
+	case BT_OCF(BT_HCI_OP_LE_SET_PATH_LOSS_REPORTING_PARAMETERS):
+		le_path_loss_set_parameters(cmd, evt);
+		break;
+
+	case BT_OCF(BT_HCI_OP_LE_SET_PATH_LOSS_REPORTING_ENABLE):
+		le_path_loss_enable(cmd, evt);
+		break;
+
+#endif /* CONFIG_BT_CTLR_LE_PATH_LOSS_MONITORING */
 #endif /* CONFIG_BT_CONN */
 
 #if defined(CONFIG_BT_CTLR_ADV_EXT)
@@ -8645,6 +8703,28 @@ static void le_req_peer_sca_complete(struct pdu_data *pdu, uint16_t handle,
 	sep->sca = scau->sca;
 }
 #endif /* CONFIG_BT_CTLR_SCA_UPDATE */
+#if defined(CONFIG_BT_CTLR_LE_PATH_LOSS_MONITORING)
+static void le_path_loss_threshold(struct pdu_data *pdu,
+				   uint16_t handle,
+				   struct net_buf *buf)
+{
+	struct bt_hci_evt_le_path_loss_threshold *sep;
+	struct node_rx_path_loss *pl_pdu;
+
+	pl_pdu = (void *)pdu;
+
+	if (!(event_mask & BT_EVT_MASK_LE_META_EVENT) ||
+	    !(le_event_mask & BT_EVT_MASK_LE_PATH_LOSS_THRESHOLD)) {
+		return;
+	}
+
+	sep = meta_evt(buf, BT_HCI_EVT_LE_PATH_LOSS_THRESHOLD, sizeof(*sep));
+
+	sep->handle = sys_cpu_to_le16(handle);
+	sep->current_path_loss = pl_pdu->current_path_loss;
+	sep->zone_entered      = pl_pdu->zone_entered;
+}
+#endif /* CONFIG_BT_CTLR_LE_PATH_LOSS_MONITORING */
 #endif /* CONFIG_BT_CONN */
 
 #if defined(CONFIG_BT_HCI_MESH_EXT)
@@ -8847,6 +8927,12 @@ static void encode_control(struct node_rx_pdu *node_rx,
 #endif /* CONFIG_BT_CTLR_DF_VS_CONN_IQ_REPORT_16_BITS_IQ_SAMPLES */
 		return;
 #endif /* CONFIG_BT_CTLR_DF_CONN_CTE_RX */
+
+#if defined(CONFIG_BT_CTLR_LE_PATH_LOSS_MONITORING)
+	case NODE_RX_TYPE_PATH_LOSS:
+		le_path_loss_threshold(pdu_data, handle, buf);
+		return;
+#endif /* CONFIG_BT_CTLR_LE_PATH_LOSS_MONITORING */
 #endif /* CONFIG_BT_CONN */
 
 #if defined(CONFIG_BT_CTLR_ADV_INDICATION)
@@ -9332,6 +9418,10 @@ uint8_t hci_get_class(struct node_rx_pdu *node_rx)
 #endif /* CONFIG_BT_CTLR_PHY */
 
 			return HCI_CLASS_EVT_CONNECTION;
+#if defined(CONFIG_BT_CTLR_LE_PATH_LOSS_MONITORING)
+		case NODE_RX_TYPE_PATH_LOSS:
+			return HCI_CLASS_EVT_REQUIRED;
+#endif /* CONFIG_BT_CTLR_LE_PATH_LOSS_MONITORING */
 #endif /* CONFIG_BT_CONN */
 
 #if defined(CONFIG_BT_CTLR_SYNC_ISO) || defined(CONFIG_BT_CTLR_CONN_ISO)

subsys/bluetooth/controller/include/ll.h

@@ -343,3 +343,12 @@ void ll_coex_ticker_id_get(uint8_t * const instance_index,
 				uint8_t * const ticker_id);
 void ll_radio_state_abort(void);
 uint32_t ll_radio_state_is_idle(void);
+
+uint8_t ll_conn_set_path_loss_parameters(uint16_t handle,
+					 uint8_t  high_threshold,
+					 uint8_t  high_hysteresis,
+					 uint8_t  low_threshold,
+					 uint8_t  low_hysteresis,
+					 uint16_t min_time_spent);
+
+uint8_t ll_conn_set_path_loss_reporting(uint16_t handle, uint8_t enable);

subsys/bluetooth/controller/ll_sw/lll.h

@@ -309,6 +309,7 @@ enum node_rx_type {
 	NODE_RX_TYPE_IQ_SAMPLE_REPORT_ULL_RELEASE,
 	NODE_RX_TYPE_IQ_SAMPLE_REPORT_LLL_RELEASE,
 	NODE_RX_TYPE_SYNC_TRANSFER_RECEIVED,
+	NODE_RX_TYPE_PATH_LOSS,
 	/* Signals retention (ie non-release) of rx node */
 	NODE_RX_TYPE_RETAIN,
 

subsys/bluetooth/controller/ll_sw/lll_conn.h

@@ -14,6 +14,22 @@
 #define LLL_CONN_MIC_PASS 1
 #define LLL_CONN_MIC_FAIL 2
 
+
+struct path_loss_params {
+	uint16_t min_time_spent;
+	uint8_t  enabled;
+	uint8_t  high_threshold;
+	uint8_t  high_hysteresis;
+	uint8_t  low_threshold;
+	uint8_t  low_hysteresis;
+} __packed;
+
+struct path_loss_state {
+	uint16_t conn_handle;
+	uint16_t min_time_counter;
+	uint8_t  new_zone;
+} __packed;
+
 struct lll_tx {
 	uint16_t handle;
 	void *node;
@@ -157,6 +173,11 @@ struct lll_conn {
 	uint8_t  rssi_sample_count;
 #endif /* CONFIG_BT_CTLR_CONN_RSSI_EVENT */
 #endif /* CONFIG_BT_CTLR_CONN_RSSI */
+#if defined(CONFIG_BT_CTLR_LE_PATH_LOSS_MONITORING)
+	struct path_loss_params pl_params;
+	struct path_loss_state	pl_state;
+	uint8_t pl_current_zone;
+#endif /* CONFIG_BT_CTLR_LE_PATH_LOSS_MONITORING */
 
 #if defined(CONFIG_BT_CTLR_CONN_META)
 	struct lll_conn_meta conn_meta;

subsys/bluetooth/controller/ll_sw/ull.c

@@ -1392,6 +1392,7 @@ void ll_rx_dequeue(void)
 #if defined(CONFIG_BT_CTLR_DTM_HCI_DF_IQ_REPORT)
 	case NODE_RX_TYPE_DTM_IQ_SAMPLE_REPORT:
 #endif /* CONFIG_BT_CTLR_DTM_HCI_DF_IQ_REPORT */
+	case NODE_RX_TYPE_PATH_LOSS:
 
 	/* Ensure that at least one 'case' statement is present for this
 	 * code block.
@@ -1582,6 +1583,7 @@ void ll_rx_mem_release(void **node_rx)
 #if defined(CONFIG_BT_CTLR_ISO)
 		case NODE_RX_TYPE_ISO_PDU:
 #endif
+		case NODE_RX_TYPE_PATH_LOSS:
 
 		/* Ensure that at least one 'case' statement is present for this
 		 * code block.
@@ -2965,6 +2967,7 @@ static inline void rx_demux_rx(memq_link_t *link, struct node_rx_hdr *rx)
 #if defined(CONFIG_BT_CTLR_SCAN_INDICATION)
 	case NODE_RX_TYPE_SCAN_INDICATION:
 #endif /* CONFIG_BT_CTLR_SCAN_INDICATION */
+	case NODE_RX_TYPE_PATH_LOSS:
 
 	case NODE_RX_TYPE_RELEASE:
 	{

subsys/bluetooth/controller/ll_sw/ull_conn.c

@@ -2910,6 +2910,56 @@ uint8_t ull_conn_lll_phy_active(struct ll_conn *conn, uint8_t phys)
 	return 1;
 }
 
+#if defined(CONFIG_BT_CTLR_LE_PATH_LOSS_MONITORING)
+uint8_t ll_conn_set_path_loss_parameters(uint16_t handle,
+					 uint8_t  high_threshold,
+					 uint8_t  high_hysteresis,
+					 uint8_t  low_threshold,
+					 uint8_t  low_hysteresis,
+					 uint16_t min_time_spent)
+{
+	struct ll_conn *conn;
+
+	conn = ll_connected_get(handle);
+
+	if (!conn) {
+		return BT_HCI_ERR_UNKNOWN_CONN_ID;
+	}
+
+	conn->lll.pl_params.high_threshold  = high_threshold;
+	conn->lll.pl_params.high_hysteresis = high_hysteresis;
+	conn->lll.pl_params.low_threshold   = low_threshold;
+	conn->lll.pl_params.low_hysteresis  = low_hysteresis;
+	conn->lll.pl_params.min_time_spent  = min_time_spent;
+
+	/* Reset the counter and zone after any update from the host */
+	conn->lll.pl_state.min_time_counter = 0;
+	conn->lll.pl_current_zone = BT_HCI_LE_ZONE_ENTERED_LOW;
+
+	return BT_HCI_ERR_SUCCESS;
+}
+
+uint8_t ll_conn_set_path_loss_reporting(uint16_t handle, uint8_t enable)
+{
+	struct ll_conn *conn;
+
+	conn = ll_connected_get(handle);
+
+	if (!conn) {
+		return BT_HCI_ERR_UNKNOWN_CONN_ID;
+	}
+
+	conn->lll.pl_params.enabled = enable;
+
+	/* Reset the counter and zone after any update from the host */
+	conn->lll.pl_state.min_time_counter = 0;
+	conn->lll.pl_current_zone = BT_HCI_LE_ZONE_ENTERED_LOW;
+
+	return BT_HCI_ERR_SUCCESS;
+
+}
+#endif /* CONFIG_BT_CTLR_LE_PATH_LOSS_MONITORING */
+
 uint8_t ull_is_lll_tx_queue_empty(struct ll_conn *conn)
 {
 	return (memq_peek(conn->lll.memq_tx.head, conn->lll.memq_tx.tail, NULL) == NULL);

subsys/bluetooth/controller/ll_sw/ull_conn_internal.h

@@ -138,3 +138,13 @@ void ull_conn_resume_rx_data(struct ll_conn *conn);
  * @brief Check if the lower link layer transmit queue is empty
  */
 uint8_t ull_is_lll_tx_queue_empty(struct ll_conn *conn);
+
+/**
+ * @brief Set path loss parameters
+ */
+void ull_path_loss_set_parameters(void);
+
+/**
+ * @brief Enable path loss reporting
+ */
+void ull_enable_path_loss_reporting(void);

subsys/bluetooth/controller/ll_sw/ull_conn_types.h

@@ -301,3 +301,8 @@ struct node_rx_sca {
 	uint8_t status;
 	uint8_t sca;
 };
+
+struct node_rx_path_loss {
+	uint8_t current_path_loss;
+	uint8_t zone_entered;
+};