USB: serial: add wait_until_sent operation

commit 0693196fe7bbb5e6cafd255dfce91ff6d10bc18f upstream.

Add wait_until_sent operation which can be used to wait for hardware
buffers to drain.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 5d9b178484fdf805bfd9a6e264732d5082216088..d7bffb6fafc19a87732076a329bfa518132a10bd 100644 (file)
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -379,6 +379,22 @@ static int serial_chars_in_buffer(struct tty_struct *tty)
        return count;
 }
 
+static void serial_wait_until_sent(struct tty_struct *tty, int timeout)
+{
+       struct usb_serial_port *port = tty->driver_data;
+       struct usb_serial *serial = port->serial;
+
+       dev_dbg(tty->dev, "%s\n", __func__);
+
+       if (!port->serial->type->wait_until_sent)
+               return;
+
+       mutex_lock(&serial->disc_mutex);
+       if (!serial->disconnected)
+               port->serial->type->wait_until_sent(tty, timeout);
+       mutex_unlock(&serial->disc_mutex);
+}
+
 static void serial_throttle(struct tty_struct *tty)
 {
        struct usb_serial_port *port = tty->driver_data;
@@ -1204,6 +1220,7 @@ static const struct tty_operations serial_ops = {
        .unthrottle =           serial_unthrottle,
        .break_ctl =            serial_break,
        .chars_in_buffer =      serial_chars_in_buffer,
+       .wait_until_sent =      serial_wait_until_sent,
        .tiocmget =             serial_tiocmget,
        .tiocmset =             serial_tiocmset,
        .get_icount =           serial_get_icount,

diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index 1819b59aab2a697aa573cbf8fe4e1081292dc713..826e6fc3a24547a6a2e21244192c7bc2d9b5a48b 100644 (file)
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -267,6 +267,7 @@ struct usb_serial_driver {
                        struct usb_serial_port *port, struct ktermios *old);
        void (*break_ctl)(struct tty_struct *tty, int break_state);
        int  (*chars_in_buffer)(struct tty_struct *tty);
+       void (*wait_until_sent)(struct tty_struct *tty, long timeout);
        void (*throttle)(struct tty_struct *tty);
        void (*unthrottle)(struct tty_struct *tty);
        int  (*tiocmget)(struct tty_struct *tty);