MFC: r294362, r294414, r294753

- Fix tty_drain() and, thus, TIOCDRAIN of the current tty(4) incarnation
  to actually wait until the TX FIFOs of UARTs have be drained before
  returning. This is done by bringing the equivalent of the TS_BUSY flag
  found in the previous implementation back in an ABI-preserving way.
  Reported and tested by: Patrick Powell
- Make the code consistent with itself style-wise and bring it closer
  to style(9).
- Mark unused arguments as such.
- Make the ttystates table const.

1 files changed, 30 insertions, 7 deletions

diff --git a/sys/dev/uart/uart_tty.c b/sys/dev/uart/uart_tty.c
index e676d50..c42fe7a 100644
--- a/sys/dev/uart/uart_tty.c
+++ b/sys/dev/uart/uart_tty.c
@@ -57,6 +57,16 @@ static cn_putc_t uart_cnputc;
 static cn_grab_t uart_cngrab;
 static cn_ungrab_t uart_cnungrab;
 
+static tsw_open_t uart_tty_open;
+static tsw_close_t uart_tty_close;
+static tsw_outwakeup_t uart_tty_outwakeup;
+static tsw_inwakeup_t uart_tty_inwakeup;
+static tsw_ioctl_t uart_tty_ioctl;
+static tsw_param_t uart_tty_param;
+static tsw_modem_t uart_tty_modem;
+static tsw_free_t uart_tty_free;
+static tsw_busy_t uart_tty_busy;
+
 CONSOLE_DRIVER(uart);
 
 static struct uart_devinfo uart_console;
@@ -157,7 +167,7 @@ uart_tty_close(struct tty *tp)
 	struct uart_softc *sc;
 
 	sc = tty_softc(tp);
-	if (sc == NULL || sc->sc_leaving || !sc->sc_opened) 
+	if (sc == NULL || sc->sc_leaving || !sc->sc_opened)
 		return;
 
 	if (sc->sc_hwiflow)
@@ -169,7 +179,6 @@ uart_tty_close(struct tty *tp)
 
 	wakeup(sc);
 	sc->sc_opened = 0;
-	return;
 }
 
 static void
@@ -215,7 +224,8 @@ uart_tty_inwakeup(struct tty *tp)
 }
 
 static int
-uart_tty_ioctl(struct tty *tp, u_long cmd, caddr_t data, struct thread *td)
+uart_tty_ioctl(struct tty *tp, u_long cmd, caddr_t data,
+    struct thread *td __unused)
 {
 	struct uart_softc *sc;
 
@@ -262,8 +272,8 @@ uart_tty_param(struct tty *tp, struct termios *t)
 	}
 	stopbits = (t->c_cflag & CSTOPB) ? 2 : 1;
 	if (t->c_cflag & PARENB)
-		parity = (t->c_cflag & PARODD) ? UART_PARITY_ODD
-		    : UART_PARITY_EVEN;
+		parity = (t->c_cflag & PARODD) ? UART_PARITY_ODD :
+		    UART_PARITY_EVEN;
 	else
 		parity = UART_PARITY_NONE;
 	if (UART_PARAM(sc, t->c_ospeed, databits, stopbits, parity) != 0)
@@ -291,7 +301,7 @@ uart_tty_modem(struct tty *tp, int biton, int bitoff)
 
 	sc = tty_softc(tp);
 	if (biton != 0 || bitoff != 0)
-		UART_SETSIG(sc, SER_DELTA(bitoff|biton) | biton);
+		UART_SETSIG(sc, SER_DELTA(bitoff | biton) | biton);
 	return (sc->sc_hwsig);
 }
 
@@ -350,7 +360,7 @@ uart_tty_intr(void *arg)
 }
 
 static void
-uart_tty_free(void *arg)
+uart_tty_free(void *arg __unused)
 {
 
 	/*
@@ -361,6 +371,18 @@ uart_tty_free(void *arg)
 	 */
 }
 
+static bool
+uart_tty_busy(struct tty *tp)
+{
+	struct uart_softc *sc;
+
+	sc = tty_softc(tp);
+	if (sc == NULL || sc->sc_leaving)
+                return (FALSE);
+
+	return (sc->sc_txbusy);
+}
+
 static struct ttydevsw uart_tty_class = {
 	.tsw_flags	= TF_INITLOCK|TF_CALLOUT,
 	.tsw_open	= uart_tty_open,
@@ -371,6 +393,7 @@ static struct ttydevsw uart_tty_class = {
 	.tsw_param	= uart_tty_param,
 	.tsw_modem	= uart_tty_modem,
 	.tsw_free	= uart_tty_free,
+	.tsw_busy	= uart_tty_busy,
 };
 
 int