Bluetooth: Host: Add support for Advertising Coding Selection

Adds API for Advertising Coding Selection.

Introduces two new advertising options to configure the advertiser's
requirement concerning coding scheme when LE Coded PHY is configured.
While the Bluetooth v6.0 specification makes a distinction betweeen
preferred and required advertising PHY options, a simplification is
made to only expose the required PHY options. Inline with how LE Coded
PHY is implemented; this API will set both the primary and secondary
advertising PHY's to the same coding scheme.

The support is enabled by CONFIG_BT_EXT_ADV_CODING_SELECTION, and requires
a controller that selects CONFIG_BT_CTLR_ADV_EXT_CODING_SELECTION_SUPPORT.

Signed-off-by: Thomas Deppe <[email protected]>

Author: Thomas-Deppe

include/zephyr/bluetooth/bluetooth.h

@@ -784,6 +784,40 @@ enum {
 	 * @note Mutually exclusive with BT_LE_ADV_OPT_USE_IDENTITY.
 	 */
 	BT_LE_ADV_OPT_USE_NRPA = BIT(19),
+
+	/**
+	 * @brief Configures the advertiser to use the S=2 coding scheme for
+	 * LE Coded PHY.
+	 *
+	 * Sets the advertiser's required coding scheme to S=2, which is one
+	 * of the coding options available for LE Coded PHY. The S=2 coding
+	 * scheme offers higher data rates compared to S=8, with a trade-off
+	 * of reduced range. The coding scheme will only be set if both the
+	 * primary and secondary advertising channels indicate LE Coded Phy.
+	 * Additionally, the Controller must support the LE Feature Advertising
+	 * Coding Selection. If these conditions are not met, it will default to
+	 * no required coding scheme.
+	 *
+	 * @note Requires @kconfig{BT_EXT_ADV_CODING_SELECTION}
+	 */
+	BT_LE_ADV_OPT_REQUIRE_S2_CODING = BIT(20),
+
+	/**
+	 * @brief Configures the advertiser to use the S=8 coding scheme for
+	 * LE Coded PHY.
+	 *
+	 * Sets the advertiser's required coding scheme to S=8, which is one
+	 * of the coding options available for LE Coded PHY. The S=8 coding
+	 * scheme offers increased range compared to S=2, with a trade-off
+	 * of lower data rates. The coding scheme will only be set if both the
+	 * primary and secondary advertising channels indicate LE Coded Phy.
+	 * Additionally, the Controller must support the LE Feature Advertising
+	 * Coding Selection. If these conditions are not met, it will default to
+	 * no required coding scheme.
+	 *
+	 * @note Requires @kconfig{BT_EXT_ADV_CODING_SELECTION}
+	 */
+	BT_LE_ADV_OPT_REQUIRE_S8_CODING = BIT(21),
 };
 
 /** LE Advertising Parameters. */

include/zephyr/bluetooth/hci_types.h

@@ -198,6 +198,8 @@ struct bt_hci_cmd_hdr {
 #define BT_LE_FEAT_BIT_CONN_SUBRATING           37
 #define BT_LE_FEAT_BIT_CONN_SUBRATING_HOST_SUPP 38
 #define BT_LE_FEAT_BIT_CHANNEL_CLASSIFICATION   39
+#define BT_LE_FEAT_BIT_ADV_CODING_SEL           40
+#define BT_LE_FEAT_BIT_ADV_CODING_SEL_HOST      41
 
 #define BT_LE_FEAT_BIT_PAWR_ADVERTISER          43
 #define BT_LE_FEAT_BIT_PAWR_SCANNER             44
@@ -268,6 +270,10 @@ struct bt_hci_cmd_hdr {
 						  BT_LE_FEAT_BIT_CONN_SUBRATING_HOST_SUPP)
 #define BT_FEAT_LE_CHANNEL_CLASSIFICATION(feat)   BT_LE_FEAT_TEST(feat, \
 						  BT_LE_FEAT_BIT_CHANNEL_CLASSIFICATION)
+#define BT_FEAT_LE_ADV_CODING_SEL(feat)	          BT_LE_FEAT_TEST(feat, \
+						  BT_LE_FEAT_BIT_ADV_CODING_SEL)
+#define BT_FEAT_LE_ADV_CODING_SEL_HOST(feat)	  BT_LE_FEAT_TEST(feat, \
+						  BT_LE_FEAT_BIT_ADV_CODING_SEL_HOST)
 #define BT_FEAT_LE_PAWR_ADVERTISER(feat)	  BT_LE_FEAT_TEST(feat, \
 						  BT_LE_FEAT_BIT_PAWR_ADVERTISER)
 #define BT_FEAT_LE_PAWR_SCANNER(feat)             BT_LE_FEAT_TEST(feat, \
@@ -1538,6 +1544,30 @@ struct bt_hci_rp_le_set_ext_adv_param {
 	int8_t  tx_power;
 } __packed;
 
+#define BT_HCI_LE_ADV_PHY_OPTION_NO_REQUIRED 0x00
+#define BT_HCI_LE_ADV_PHY_OPTION_REQUIRE_S2  0x03
+#define BT_HCI_LE_ADV_PHY_OPTION_REQUIRE_S8  0x04
+
+#define BT_HCI_OP_LE_SET_EXT_ADV_PARAM_V2        BT_OP(BT_OGF_LE, 0x007F) /* 0x207F */
+struct bt_hci_cp_le_set_ext_adv_param_v2 {
+	uint8_t      handle;
+	uint16_t     props;
+	uint8_t      prim_min_interval[3];
+	uint8_t      prim_max_interval[3];
+	uint8_t      prim_channel_map;
+	uint8_t      own_addr_type;
+	bt_addr_le_t peer_addr;
+	uint8_t      filter_policy;
+	int8_t       tx_power;
+	uint8_t      prim_adv_phy;
+	uint8_t      sec_adv_max_skip;
+	uint8_t      sec_adv_phy;
+	uint8_t      sid;
+	uint8_t      scan_req_notify_enable;
+	uint8_t      prim_adv_phy_opt;
+	uint8_t      sec_adv_phy_opt;
+} __packed;
+
 #define BT_HCI_LE_EXT_ADV_OP_INTERM_FRAG        0x00
 #define BT_HCI_LE_EXT_ADV_OP_FIRST_FRAG         0x01
 #define BT_HCI_LE_EXT_ADV_OP_LAST_FRAG          0x02

subsys/bluetooth/Kconfig.adv

@@ -68,6 +68,14 @@ config BT_PER_ADV_SYNC_RSP
 	  Select this to enable Periodic Advertising with Responses Sync
 	  API support.
 
+config BT_EXT_ADV_CODING_SELECTION
+	bool "Advertising Coding Selection support"
+	depends on !HAS_BT_CTLR || BT_CTLR_PHY_CODED
+	help
+	  Select this to enable Advertising Coding Selection API support.
+	  This allows the Host to indicate their strict requirement
+	  concerning coding scheme when using Extended Advertising.
+
 if BT_PER_ADV_SYNC
 
 config BT_PER_ADV_SYNC_MAX

subsys/bluetooth/controller/Kconfig

@@ -45,6 +45,10 @@ config BT_CTLR_PHY_CODED_SUPPORT
 config BT_CTLR_ADV_EXT_SUPPORT
 	bool
 
+config BT_CTLR_ADV_EXT_CODING_SELECTION_SUPPORT
+	depends on BT_CTLR_PHY_CODED_SUPPORT
+	bool
+
 config BT_CTLR_ADV_PERIODIC_SUPPORT
 	depends on BT_CTLR_ADV_EXT_SUPPORT
 	bool
@@ -780,6 +784,14 @@ config BT_CTLR_ADV_PERIODIC_RSP
 	  Enable support for Bluetooth 5.4 LE Periodic Advertising with
 	  Responses in the Controller.
 
+config BT_CTLR_ADV_EXT_CODING_SELECTION
+	bool "Advertising Coding Selection support"
+	depends on BT_CTLR_PHY_CODED && BT_CTLR_ADV_EXT_CODING_SELECTION_SUPPORT
+	default y if BT_EXT_ADV_CODING_SELECTION
+	help
+	  Enable support for Bluetooth 6.0 Advertising Coding Selection
+	  in the Controller.
+
 if BT_CTLR_ADV_PERIODIC
 
 config BT_CTLR_ADV_PERIODIC_ADI_SUPPORT

subsys/bluetooth/host/adv.c

@@ -1121,20 +1121,32 @@ static int le_ext_adv_param_set(struct bt_le_ext_adv *adv,
 				const struct bt_le_adv_param *param,
 				bool  has_scan_data)
 {
-	struct bt_hci_cp_le_set_ext_adv_param *cp;
+	struct bt_hci_cp_le_set_ext_adv_param_v2 *cp;
+
+	uint16_t opcode;
+	uint16_t size;
 	bool dir_adv = param->peer != NULL, scannable;
 	struct net_buf *buf, *rsp;
 	int err;
 	enum adv_name_type name_type;
 	uint16_t props = 0;
 
-	buf = bt_hci_cmd_create(BT_HCI_OP_LE_SET_EXT_ADV_PARAM, sizeof(*cp));
+	if (IS_ENABLED(CONFIG_BT_EXT_ADV_CODING_SELECTION) &&
+	    BT_FEAT_LE_ADV_CODING_SEL(bt_dev.le.features)) {
+		opcode = BT_HCI_OP_LE_SET_EXT_ADV_PARAM_V2;
+		size = sizeof(struct bt_hci_cp_le_set_ext_adv_param_v2);
+	} else {
+		opcode = BT_HCI_OP_LE_SET_EXT_ADV_PARAM;
+		size = sizeof(struct bt_hci_cp_le_set_ext_adv_param);
+	}
+
+	buf = bt_hci_cmd_create(opcode, size);
 	if (!buf) {
 		return -ENOBUFS;
 	}
 
-	cp = net_buf_add(buf, sizeof(*cp));
-	(void)memset(cp, 0, sizeof(*cp));
+	cp = net_buf_add(buf, size);
+	(void)memset(cp, 0, size);
 
 	adv->options = param->options;
 
@@ -1171,6 +1183,22 @@ static int le_ext_adv_param_set(struct bt_le_ext_adv *adv,
 	if (param->options & BT_LE_ADV_OPT_CODED) {
 		cp->prim_adv_phy = BT_HCI_LE_PHY_CODED;
 		cp->sec_adv_phy = BT_HCI_LE_PHY_CODED;
+
+		if (IS_ENABLED(CONFIG_BT_EXT_ADV_CODING_SELECTION) &&
+		    opcode == BT_HCI_OP_LE_SET_EXT_ADV_PARAM_V2) {
+			uint8_t adv_phy_opt;
+
+			if (param->options & BT_LE_ADV_OPT_REQUIRE_S8_CODING) {
+				adv_phy_opt = BT_HCI_LE_ADV_PHY_OPTION_REQUIRE_S8;
+			} else if (param->options & BT_LE_ADV_OPT_REQUIRE_S2_CODING) {
+				adv_phy_opt = BT_HCI_LE_ADV_PHY_OPTION_REQUIRE_S2;
+			} else {
+				adv_phy_opt = BT_HCI_LE_ADV_PHY_OPTION_NO_REQUIRED;
+			}
+
+			cp->prim_adv_phy_opt = adv_phy_opt;
+			cp->sec_adv_phy_opt = adv_phy_opt;
+		}
 	}
 
 	if (!(param->options & BT_LE_ADV_OPT_EXT_ADV)) {
@@ -1222,7 +1250,7 @@ static int le_ext_adv_param_set(struct bt_le_ext_adv *adv,
 	cp->sec_adv_max_skip = param->secondary_max_skip;
 
 	cp->props = sys_cpu_to_le16(props);
-	err = bt_hci_cmd_send_sync(BT_HCI_OP_LE_SET_EXT_ADV_PARAM, buf, &rsp);
+	err = bt_hci_cmd_send_sync(opcode, buf, &rsp);
 	if (err) {
 		return err;
 	}

tests/bluetooth/init/prj_host_6_x.conf

@@ -0,0 +1,9 @@
+CONFIG_BT=y
+CONFIG_BT_BROADCASTER=y
+CONFIG_BT_PERIPHERAL=y
+CONFIG_BT_OBSERVER=y
+CONFIG_BT_CENTRAL=y
+CONFIG_BT_EXT_ADV=y
+CONFIG_BT_CTLR_PHY_CODED=y
+CONFIG_BT_EXT_ADV_CODING_SELECTION=y
+CONFIG_ZTEST=y

tests/bluetooth/init/testcase.yaml

@@ -349,3 +349,10 @@ tests:
       - CONFIG_BT_RECV_WORKQ_BT=y
     platform_allow:
       - nrf52840dk/nrf52840
+  bluetooth.init.test_host_6_x:
+    extra_args: CONF_FILE=prj_host_6_x.conf
+    platform_allow:
+      - qemu_cortex_m3
+      - nrf52840dk/nrf52840
+    integration_platforms:
+      - nrf52840dk/nrf52840