Bluetooth: Add MGMT capability flags for tx power and ext advertising

For new advertising features, it will be important for userspace to
know the capabilities of the controller and kernel. If the controller
and kernel support extended advertising, we include flags indicating
hardware offloading support and support for setting tx power of adv
instances.

In the future, vendor-specific commands may allow the setting of tx
power in advertising instances, but for now this feature is only
marked available if extended advertising is supported.

This change is manually verified in userspace by ensuring the
advertising manager's supported_flags field is updated with new flags on
hatch chromebook (ext advertising supported).
Signed-off-by: NDaniel Winkler <danielwinkler@google.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

include/net/bluetooth/mgmt.h

@@ -572,6 +572,8 @@ struct mgmt_rp_add_advertising {
 #define MGMT_ADV_FLAG_SEC_1M 		BIT(7)
 #define MGMT_ADV_FLAG_SEC_2M 		BIT(8)
 #define MGMT_ADV_FLAG_SEC_CODED 	BIT(9)
+#define MGMT_ADV_FLAG_CAN_SET_TX_POWER	BIT(10)
+#define MGMT_ADV_FLAG_HW_OFFLOAD	BIT(11)
 
 #define MGMT_ADV_FLAG_SEC_MASK	(MGMT_ADV_FLAG_SEC_1M | MGMT_ADV_FLAG_SEC_2M | \
 				 MGMT_ADV_FLAG_SEC_CODED)

net/bluetooth/mgmt.c

@@ -7206,6 +7206,8 @@ static u32 get_supported_adv_flags(struct hci_dev *hdev)
 
 	if (ext_adv_capable(hdev)) {
 		flags |= MGMT_ADV_FLAG_SEC_1M;
+		flags |= MGMT_ADV_FLAG_HW_OFFLOAD;
+		flags |= MGMT_ADV_FLAG_CAN_SET_TX_POWER;
 
 		if (hdev->le_features[1] & HCI_LE_PHY_2M)
 			flags |= MGMT_ADV_FLAG_SEC_2M;