Bluetooth: Add support for reading LE supported states

The LE supported states indicate the states and state combinations that
the link layer supports. This is important information for knowing what
operations are possible when dealing with multiple connected devices.
This patch adds reading of the supported states to the HCI init
sequence.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

include/net/bluetooth/hci.h

@@ -1045,6 +1045,12 @@ struct hci_rp_le_ltk_neg_reply {
 	__le16	handle;
 } __packed;
 
+#define HCI_OP_LE_READ_SUPPORTED_STATES	0x201c
+struct hci_rp_le_read_supported_states {
+	__u8	status;
+	__u8	le_states[8];
+} __packed;
+
 /* ---- HCI Events ---- */
 #define HCI_EV_INQUIRY_COMPLETE		0x01
 

include/net/bluetooth/hci_core.h

@@ -154,6 +154,7 @@ struct hci_dev {
 	__u8		host_features[8];
 	__u8		le_features[8];
 	__u8		le_white_list_size;
+	__u8		le_states[8];
 	__u8		commands[64];
 	__u8		hci_ver;
 	__u16		hci_rev;

net/bluetooth/hci_event.c

@@ -617,6 +617,9 @@ static void le_setup(struct hci_dev *hdev)
 
 	/* Read LE White List Size */
 	hci_send_cmd(hdev, HCI_OP_LE_READ_WHITE_LIST_SIZE, 0, NULL);
+
+	/* Read LE Supported States */
+	hci_send_cmd(hdev, HCI_OP_LE_READ_SUPPORTED_STATES, 0, NULL);
 }
 
 static void hci_setup(struct hci_dev *hdev)
@@ -1346,6 +1349,19 @@ static void hci_cc_le_ltk_neg_reply(struct hci_dev *hdev, struct sk_buff *skb)
 	hci_req_complete(hdev, HCI_OP_LE_LTK_NEG_REPLY, rp->status);
 }
 
+static void hci_cc_le_read_supported_states(struct hci_dev *hdev,
+					    struct sk_buff *skb)
+{
+	struct hci_rp_le_read_supported_states *rp = (void *) skb->data;
+
+	BT_DBG("%s status 0x%2.2x", hdev->name, rp->status);
+
+	if (!rp->status)
+		memcpy(hdev->le_states, rp->le_states, 8);
+
+	hci_req_complete(hdev, HCI_OP_LE_READ_SUPPORTED_STATES, rp->status);
+}
+
 static void hci_cc_write_le_host_supported(struct hci_dev *hdev,
 					   struct sk_buff *skb)
 {
@@ -2712,6 +2728,10 @@ static void hci_cmd_complete_evt(struct hci_dev *hdev, struct sk_buff *skb)
 		hci_cc_le_ltk_neg_reply(hdev, skb);
 		break;
 
+	case HCI_OP_LE_READ_SUPPORTED_STATES:
+		hci_cc_le_read_supported_states(hdev, skb);
+		break;
+
 	case HCI_OP_WRITE_LE_HOST_SUPPORTED:
 		hci_cc_write_le_host_supported(hdev, skb);
 		break;