Bluetooth: Emit controller suspend and resume events

Emit controller suspend and resume events when we are ready for suspend
and we've resumed from suspend.

The controller suspend event will report whatever suspend state was
successfully entered. The controller resume event will check the first
HCI event that was received after we finished preparing for suspend and,
if it was a connection event, store the address of the peer that caused
the event. If it was not a connection event, we mark the wake reason as
an unexpected event.

Here is a sample btmon trace with these events:

@ MGMT Event: Controller Suspended (0x002d) plen 1
        Suspend state: Page scanning and/or passive scanning (2)

@ MGMT Event: Controller Resumed (0x002e) plen 8
        Wake reason: Remote wake due to peer device connection (2)
        LE Address: CD:F3:CD:13:C5:9A (OUI CD-F3-CD)
Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Reviewed-by: Miao-chen Chou <mcchou@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

include/net/bluetooth/hci_core.h

@@ -484,6 +484,9 @@ struct hci_dev {
 	enum suspended_state	suspend_state;
 	bool			scanning_paused;
 	bool			suspended;
+	u8			wake_reason;
+	bdaddr_t		wake_addr;
+	u8			wake_addr_type;
 
 	wait_queue_head_t	suspend_wait_q;
 	DECLARE_BITMAP(suspend_tasks, __SUSPEND_NUM_TASKS);

include/net/bluetooth/mgmt.h

@@ -1042,3 +1042,7 @@ struct mgmt_ev_controller_resume {
 	__u8	wake_reason;
 	struct mgmt_addr_info addr;
 } __packed;
+
+#define MGMT_WAKE_REASON_NON_BT_WAKE		0x0
+#define MGMT_WAKE_REASON_UNEXPECTED		0x1
+#define MGMT_WAKE_REASON_REMOTE_WAKE		0x2

net/bluetooth/hci_core.c

@@ -3497,12 +3497,24 @@ static int hci_change_suspend_state(struct hci_dev *hdev,
 	return hci_suspend_wait_event(hdev);
 }
 
+static void hci_clear_wake_reason(struct hci_dev *hdev)
+{
+	hci_dev_lock(hdev);
+
+	hdev->wake_reason = 0;
+	bacpy(&hdev->wake_addr, BDADDR_ANY);
+	hdev->wake_addr_type = 0;
+
+	hci_dev_unlock(hdev);
+}
+
 static int hci_suspend_notifier(struct notifier_block *nb, unsigned long action,
 				void *data)
 {
 	struct hci_dev *hdev =
 		container_of(nb, struct hci_dev, suspend_notifier);
 	int ret = 0;
+	u8 state = BT_RUNNING;
 
 	/* If powering down, wait for completion. */
 	if (mgmt_powering_down(hdev)) {
@@ -3523,15 +3535,27 @@ static int hci_suspend_notifier(struct notifier_block *nb, unsigned long action,
 		 *  - Second, program event filter/whitelist and enable scan
 		 */
 		ret = hci_change_suspend_state(hdev, BT_SUSPEND_DISCONNECT);
+		if (!ret)
+			state = BT_SUSPEND_DISCONNECT;
 
 		/* Only configure whitelist if disconnect succeeded and wake
 		 * isn't being prevented.
 		 */
-		if (!ret && !(hdev->prevent_wake && hdev->prevent_wake(hdev)))
+		if (!ret && !(hdev->prevent_wake && hdev->prevent_wake(hdev))) {
 			ret = hci_change_suspend_state(hdev,
 						BT_SUSPEND_CONFIGURE_WAKE);
+			if (!ret)
+				state = BT_SUSPEND_CONFIGURE_WAKE;
+		}
+
+		hci_clear_wake_reason(hdev);
+		mgmt_suspending(hdev, state);
+
 	} else if (action == PM_POST_SUSPEND) {
 		ret = hci_change_suspend_state(hdev, BT_RUNNING);
+
+		mgmt_resuming(hdev, hdev->wake_reason, &hdev->wake_addr,
+			      hdev->wake_addr_type);
 	}
 
 done:

net/bluetooth/hci_event.c

@@ -6000,6 +6000,75 @@ static bool hci_get_cmd_complete(struct hci_dev *hdev, u16 opcode,
 	return true;
 }
 
+static void hci_store_wake_reason(struct hci_dev *hdev, u8 event,
+				  struct sk_buff *skb)
+{
+	struct hci_ev_le_advertising_info *adv;
+	struct hci_ev_le_direct_adv_info *direct_adv;
+	struct hci_ev_le_ext_adv_report *ext_adv;
+	const struct hci_ev_conn_complete *conn_complete = (void *)skb->data;
+	const struct hci_ev_conn_request *conn_request = (void *)skb->data;
+
+	hci_dev_lock(hdev);
+
+	/* If we are currently suspended and this is the first BT event seen,
+	 * save the wake reason associated with the event.
+	 */
+	if (!hdev->suspended || hdev->wake_reason)
+		goto unlock;
+
+	/* Default to remote wake. Values for wake_reason are documented in the
+	 * Bluez mgmt api docs.
+	 */
+	hdev->wake_reason = MGMT_WAKE_REASON_REMOTE_WAKE;
+
+	/* Once configured for remote wakeup, we should only wake up for
+	 * reconnections. It's useful to see which device is waking us up so
+	 * keep track of the bdaddr of the connection event that woke us up.
+	 */
+	if (event == HCI_EV_CONN_REQUEST) {
+		bacpy(&hdev->wake_addr, &conn_complete->bdaddr);
+		hdev->wake_addr_type = BDADDR_BREDR;
+	} else if (event == HCI_EV_CONN_COMPLETE) {
+		bacpy(&hdev->wake_addr, &conn_request->bdaddr);
+		hdev->wake_addr_type = BDADDR_BREDR;
+	} else if (event == HCI_EV_LE_META) {
+		struct hci_ev_le_meta *le_ev = (void *)skb->data;
+		u8 subevent = le_ev->subevent;
+		u8 *ptr = &skb->data[sizeof(*le_ev)];
+		u8 num_reports = *ptr;
+
+		if ((subevent == HCI_EV_LE_ADVERTISING_REPORT ||
+		     subevent == HCI_EV_LE_DIRECT_ADV_REPORT ||
+		     subevent == HCI_EV_LE_EXT_ADV_REPORT) &&
+		    num_reports) {
+			adv = (void *)(ptr + 1);
+			direct_adv = (void *)(ptr + 1);
+			ext_adv = (void *)(ptr + 1);
+
+			switch (subevent) {
+			case HCI_EV_LE_ADVERTISING_REPORT:
+				bacpy(&hdev->wake_addr, &adv->bdaddr);
+				hdev->wake_addr_type = adv->bdaddr_type;
+				break;
+			case HCI_EV_LE_DIRECT_ADV_REPORT:
+				bacpy(&hdev->wake_addr, &direct_adv->bdaddr);
+				hdev->wake_addr_type = direct_adv->bdaddr_type;
+				break;
+			case HCI_EV_LE_EXT_ADV_REPORT:
+				bacpy(&hdev->wake_addr, &ext_adv->bdaddr);
+				hdev->wake_addr_type = ext_adv->bdaddr_type;
+				break;
+			}
+		}
+	} else {
+		hdev->wake_reason = MGMT_WAKE_REASON_UNEXPECTED;
+	}
+
+unlock:
+	hci_dev_unlock(hdev);
+}
+
 void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb)
 {
 	struct hci_event_hdr *hdr = (void *) skb->data;
@@ -6033,6 +6102,9 @@ void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb)
 
 	skb_pull(skb, HCI_EVENT_HDR_SIZE);
 
+	/* Store wake reason if we're suspended */
+	hci_store_wake_reason(hdev, event, skb);
+
 	switch (event) {
 	case HCI_EV_INQUIRY_COMPLETE:
 		hci_inquiry_complete_evt(hdev, skb);