usb: typec: ucsi: Store the notification mask

The driver needs to ignore any Connector Change Events
before the Connector Change Indication notifications have
actually been enabled. This adds a check to
ucsi_connector_change() function to make sure the function
does not try to process the event unless the Connector
Change notifications have been enabled.

It is quite common that the firmware representing the "PPM"
(Platform Policy Manager) starts generating Connector Change
notifications even when only the Command Completion
notifications are enabled.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20191230133431.63445-2-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/ucsi/ucsi.c

@@ -189,7 +189,7 @@ int ucsi_resume(struct ucsi *ucsi)
 	u64 command;
 
 	/* Restore UCSI notification enable mask after system resume */
-	command = UCSI_SET_NOTIFICATION_ENABLE | UCSI_ENABLE_NTFY_ALL;
+	command = UCSI_SET_NOTIFICATION_ENABLE | ucsi->ntfy;
 
 	return ucsi_send_command(ucsi, command, NULL, 0);
 }
@@ -589,6 +589,11 @@ void ucsi_connector_change(struct ucsi *ucsi, u8 num)
 {
 	struct ucsi_connector *con = &ucsi->connector[num - 1];
 
+	if (!(ucsi->ntfy & UCSI_ENABLE_NTFY_CONNECTOR_CHANGE)) {
+		dev_dbg(ucsi->dev, "Bogus connetor change event\n");
+		return;
+	}
+
 	if (!test_and_set_bit(EVENT_PENDING, &ucsi->flags))
 		schedule_work(&con->work);
 }
@@ -656,7 +661,7 @@ static int ucsi_role_cmd(struct ucsi_connector *con, u64 command)
 		ucsi_reset_ppm(con->ucsi);
 		mutex_unlock(&con->ucsi->ppm_lock);
 
-		c = UCSI_SET_NOTIFICATION_ENABLE | UCSI_ENABLE_NTFY_ALL;
+		c = UCSI_SET_NOTIFICATION_ENABLE | con->ucsi->ntfy;
 		ucsi_send_command(con->ucsi, c, NULL, 0);
 
 		ucsi_reset_connector(con, true);
@@ -890,8 +895,8 @@ int ucsi_init(struct ucsi *ucsi)
 	}
 
 	/* Enable basic notifications */
-	command = UCSI_SET_NOTIFICATION_ENABLE;
-	command |= UCSI_ENABLE_NTFY_CMD_COMPLETE | UCSI_ENABLE_NTFY_ERROR;
+	ucsi->ntfy = UCSI_ENABLE_NTFY_CMD_COMPLETE | UCSI_ENABLE_NTFY_ERROR;
+	command = UCSI_SET_NOTIFICATION_ENABLE | ucsi->ntfy;
 	ret = ucsi_run_command(ucsi, command, NULL, 0);
 	if (ret < 0)
 		goto err_reset;
@@ -923,7 +928,7 @@ int ucsi_init(struct ucsi *ucsi)
 	}
 
 	/* Enable all notifications */
-	command = UCSI_SET_NOTIFICATION_ENABLE | UCSI_ENABLE_NTFY_ALL;
+	command = UCSI_SET_NOTIFICATION_ENABLE | ucsi->ntfy;
 	ret = ucsi_run_command(ucsi, command, NULL, 0);
 	if (ret < 0)
 		goto err_unregister;

drivers/usb/typec/ucsi/ucsi.h

@@ -269,6 +269,9 @@ struct ucsi {
 	/* PPM Communication lock */
 	struct mutex ppm_lock;
 
+	/* The latest "Notification Enable" bits (SET_NOTIFICATION_ENABLE) */
+	u64 ntfy;
+
 	/* PPM communication flags */
 	unsigned long flags;
 #define EVENT_PENDING	0