1 files changed, 474 insertions, 183 deletions

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 246b823c1b2..fbf6c5ad222 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -50,16 +50,11 @@ static struct lock_class_key port_lock_key;
 
 #define HIGH_BITS_OFFSET	((sizeof(long)-sizeof(int))*8)
 
-#ifdef CONFIG_SERIAL_CORE_CONSOLE
-#define uart_console(port)	((port)->cons && (port)->cons->index == (port)->line)
-#else
-#define uart_console(port)	(0)
-#endif
-
 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
 					struct ktermios *old_termios);
 static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
-static void uart_change_pm(struct uart_state *state, int pm_state);
+static void uart_change_pm(struct uart_state *state,
+			   enum uart_pm_state pm_state);
 
 static void uart_port_shutdown(struct tty_port *port);
 
@@ -94,8 +89,7 @@ static void __uart_start(struct tty_struct *tty)
 	struct uart_state *state = tty->driver_data;
 	struct uart_port *port = state->uart_port;
 
-	if (!uart_circ_empty(&state->xmit) && state->xmit.buf &&
-	    !tty->stopped && !tty->hw_stopped)
+	if (!tty->stopped && !tty->hw_stopped)
 		port->ops->start_tx(port);
 }
 
@@ -143,6 +137,11 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
 		return 1;
 
 	/*
+	 * Make sure the device is in D0 state.
+	 */
+	uart_change_pm(state, UART_PM_STATE_ON);
+
+	/*
 	 * Initialise and allocate the transmit and temporary
 	 * buffer.
 	 */
@@ -159,7 +158,7 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
 	retval = uport->ops->startup(uport);
 	if (retval == 0) {
 		if (uart_console(uport) && uport->cons->cflag) {
-			tty->termios->c_cflag = uport->cons->cflag;
+			tty->termios.c_cflag = uport->cons->cflag;
 			uport->cons->cflag = 0;
 		}
 		/*
@@ -172,11 +171,15 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
 			 * Setup the RTS and DTR signals once the
 			 * port is open and ready to respond.
 			 */
-			if (tty->termios->c_cflag & CBAUD)
+			if (tty->termios.c_cflag & CBAUD)
 				uart_set_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
 		}
-
-		if (port->flags & ASYNC_CTS_FLOW) {
+		/*
+		 * if hw support flow control without software intervention,
+		 * then skip the below check
+		 */
+		if (tty_port_cts_enabled(port) &&
+		    !(uport->flags & UPF_HARD_FLOW)) {
 			spin_lock_irq(&uport->lock);
 			if (!(uport->ops->get_mctrl(uport) & TIOCM_CTS))
 				tty->hw_stopped = 1;
@@ -240,7 +243,7 @@ static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
 		/*
 		 * Turn off DTR and RTS early.
 		 */
-		if (!tty || (tty->termios->c_cflag & HUPCL))
+		if (!tty || (tty->termios.c_cflag & HUPCL))
 			uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
 
 		uart_port_shutdown(port);
@@ -440,10 +443,10 @@ static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
 	 * If we have no tty, termios, or the port does not exist,
 	 * then we can't set the parameters for this port.
 	 */
-	if (!tty || !tty->termios || uport->type == PORT_UNKNOWN)
+	if (!tty || uport->type == PORT_UNKNOWN)
 		return;
 
-	termios = tty->termios;
+	termios = &tty->termios;
 
 	/*
 	 * Set flags based on termios cflag
@@ -610,105 +613,126 @@ static void uart_send_xchar(struct tty_struct *tty, char ch)
 static void uart_throttle(struct tty_struct *tty)
 {
 	struct uart_state *state = tty->driver_data;
+	struct uart_port *port = state->uart_port;
+	uint32_t mask = 0;
 
 	if (I_IXOFF(tty))
+		mask |= UPF_SOFT_FLOW;
+	if (tty->termios.c_cflag & CRTSCTS)
+		mask |= UPF_HARD_FLOW;
+
+	if (port->flags & mask) {
+		port->ops->throttle(port);
+		mask &= ~port->flags;
+	}
+
+	if (mask & UPF_SOFT_FLOW)
 		uart_send_xchar(tty, STOP_CHAR(tty));
 
-	if (tty->termios->c_cflag & CRTSCTS)
-		uart_clear_mctrl(state->uart_port, TIOCM_RTS);
+	if (mask & UPF_HARD_FLOW)
+		uart_clear_mctrl(port, TIOCM_RTS);
 }
 
 static void uart_unthrottle(struct tty_struct *tty)
 {
 	struct uart_state *state = tty->driver_data;
 	struct uart_port *port = state->uart_port;
+	uint32_t mask = 0;
 
-	if (I_IXOFF(tty)) {
+	if (I_IXOFF(tty))
+		mask |= UPF_SOFT_FLOW;
+	if (tty->termios.c_cflag & CRTSCTS)
+		mask |= UPF_HARD_FLOW;
+
+	if (port->flags & mask) {
+		port->ops->unthrottle(port);
+		mask &= ~port->flags;
+	}
+
+	if (mask & UPF_SOFT_FLOW) {
 		if (port->x_char)
 			port->x_char = 0;
 		else
 			uart_send_xchar(tty, START_CHAR(tty));
 	}
 
-	if (tty->termios->c_cflag & CRTSCTS)
+	if (mask & UPF_HARD_FLOW)
 		uart_set_mctrl(port, TIOCM_RTS);
 }
 
-static int uart_get_info(struct uart_state *state,
-			 struct serial_struct __user *retinfo)
+static void do_uart_get_info(struct tty_port *port,
+			struct serial_struct *retinfo)
 {
+	struct uart_state *state = container_of(port, struct uart_state, port);
 	struct uart_port *uport = state->uart_port;
-	struct tty_port *port = &state->port;
-	struct serial_struct tmp;
-
-	memset(&tmp, 0, sizeof(tmp));
 
-	/* Ensure the state we copy is consistent and no hardware changes
-	   occur as we go */
-	mutex_lock(&port->mutex);
+	memset(retinfo, 0, sizeof(*retinfo));
 
-	tmp.type	    = uport->type;
-	tmp.line	    = uport->line;
-	tmp.port	    = uport->iobase;
+	retinfo->type	    = uport->type;
+	retinfo->line	    = uport->line;
+	retinfo->port	    = uport->iobase;
 	if (HIGH_BITS_OFFSET)
-		tmp.port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
-	tmp.irq		    = uport->irq;
-	tmp.flags	    = uport->flags;
-	tmp.xmit_fifo_size  = uport->fifosize;
-	tmp.baud_base	    = uport->uartclk / 16;
-	tmp.close_delay	    = jiffies_to_msecs(port->close_delay) / 10;
-	tmp.closing_wait    = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
+		retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
+	retinfo->irq		    = uport->irq;
+	retinfo->flags	    = uport->flags;
+	retinfo->xmit_fifo_size  = uport->fifosize;
+	retinfo->baud_base	    = uport->uartclk / 16;
+	retinfo->close_delay	    = jiffies_to_msecs(port->close_delay) / 10;
+	retinfo->closing_wait    = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 				ASYNC_CLOSING_WAIT_NONE :
 				jiffies_to_msecs(port->closing_wait) / 10;
-	tmp.custom_divisor  = uport->custom_divisor;
-	tmp.hub6	    = uport->hub6;
-	tmp.io_type         = uport->iotype;
-	tmp.iomem_reg_shift = uport->regshift;
-	tmp.iomem_base      = (void *)(unsigned long)uport->mapbase;
+	retinfo->custom_divisor  = uport->custom_divisor;
+	retinfo->hub6	    = uport->hub6;
+	retinfo->io_type         = uport->iotype;
+	retinfo->iomem_reg_shift = uport->regshift;
+	retinfo->iomem_base      = (void *)(unsigned long)uport->mapbase;
+}
 
+static void uart_get_info(struct tty_port *port,
+			struct serial_struct *retinfo)
+{
+	/* Ensure the state we copy is consistent and no hardware changes
+	   occur as we go */
+	mutex_lock(&port->mutex);
+	do_uart_get_info(port, retinfo);
 	mutex_unlock(&port->mutex);
+}
+
+static int uart_get_info_user(struct tty_port *port,
+			 struct serial_struct __user *retinfo)
+{
+	struct serial_struct tmp;
+	uart_get_info(port, &tmp);
 
 	if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
 		return -EFAULT;
 	return 0;
 }
 
-static int uart_set_info(struct tty_struct *tty, struct uart_state *state,
-			 struct serial_struct __user *newinfo)
+static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
+			 struct uart_state *state,
+			 struct serial_struct *new_info)
 {
-	struct serial_struct new_serial;
 	struct uart_port *uport = state->uart_port;
-	struct tty_port *port = &state->port;
 	unsigned long new_port;
 	unsigned int change_irq, change_port, closing_wait;
 	unsigned int old_custom_divisor, close_delay;
 	upf_t old_flags, new_flags;
 	int retval = 0;
 
-	if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
-		return -EFAULT;
-
-	new_port = new_serial.port;
+	new_port = new_info->port;
 	if (HIGH_BITS_OFFSET)
-		new_port += (unsigned long) new_serial.port_high << HIGH_BITS_OFFSET;
+		new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
 
-	new_serial.irq = irq_canonicalize(new_serial.irq);
-	close_delay = msecs_to_jiffies(new_serial.close_delay * 10);
-	closing_wait = new_serial.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
+	new_info->irq = irq_canonicalize(new_info->irq);
+	close_delay = msecs_to_jiffies(new_info->close_delay * 10);
+	closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 			ASYNC_CLOSING_WAIT_NONE :
-			msecs_to_jiffies(new_serial.closing_wait * 10);
+			msecs_to_jiffies(new_info->closing_wait * 10);
 
-	/*
-	 * This semaphore protects port->count.  It is also
-	 * very useful to prevent opens.  Also, take the
-	 * port configuration semaphore to make sure that a
-	 * module insertion/removal doesn't change anything
-	 * under us.
-	 */
-	mutex_lock(&port->mutex);
 
 	change_irq  = !(uport->flags & UPF_FIXED_PORT)
-		&& new_serial.irq != uport->irq;
+		&& new_info->irq != uport->irq;
 
 	/*
 	 * Since changing the 'type' of the port changes its resource
@@ -717,29 +741,29 @@ static int uart_set_info(struct tty_struct *tty, struct uart_state *state,
 	 */
 	change_port = !(uport->flags & UPF_FIXED_PORT)
 		&& (new_port != uport->iobase ||
-		    (unsigned long)new_serial.iomem_base != uport->mapbase ||
-		    new_serial.hub6 != uport->hub6 ||
-		    new_serial.io_type != uport->iotype ||
-		    new_serial.iomem_reg_shift != uport->regshift ||
-		    new_serial.type != uport->type);
+		    (unsigned long)new_info->iomem_base != uport->mapbase ||
+		    new_info->hub6 != uport->hub6 ||
+		    new_info->io_type != uport->iotype ||
+		    new_info->iomem_reg_shift != uport->regshift ||
+		    new_info->type != uport->type);
 
 	old_flags = uport->flags;
-	new_flags = new_serial.flags;
+	new_flags = new_info->flags;
 	old_custom_divisor = uport->custom_divisor;
 
 	if (!capable(CAP_SYS_ADMIN)) {
 		retval = -EPERM;
 		if (change_irq || change_port ||
-		    (new_serial.baud_base != uport->uartclk / 16) ||
+		    (new_info->baud_base != uport->uartclk / 16) ||
 		    (close_delay != port->close_delay) ||
 		    (closing_wait != port->closing_wait) ||
-		    (new_serial.xmit_fifo_size &&
-		     new_serial.xmit_fifo_size != uport->fifosize) ||
+		    (new_info->xmit_fifo_size &&
+		     new_info->xmit_fifo_size != uport->fifosize) ||
 		    (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
 			goto exit;
 		uport->flags = ((uport->flags & ~UPF_USR_MASK) |
 			       (new_flags & UPF_USR_MASK));
-		uport->custom_divisor = new_serial.custom_divisor;
+		uport->custom_divisor = new_info->custom_divisor;
 		goto check_and_exit;
 	}
 
@@ -747,10 +771,10 @@ static int uart_set_info(struct tty_struct *tty, struct uart_state *state,
 	 * Ask the low level driver to verify the settings.
 	 */
 	if (uport->ops->verify_port)
-		retval = uport->ops->verify_port(uport, &new_serial);
+		retval = uport->ops->verify_port(uport, new_info);
 
-	if ((new_serial.irq >= nr_irqs) || (new_serial.irq < 0) ||
-	    (new_serial.baud_base < 9600))
+	if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
+	    (new_info->baud_base < 9600))
 		retval = -EINVAL;
 
 	if (retval)
@@ -790,11 +814,11 @@ static int uart_set_info(struct tty_struct *tty, struct uart_state *state,
 			uport->ops->release_port(uport);
 
 		uport->iobase = new_port;
-		uport->type = new_serial.type;
-		uport->hub6 = new_serial.hub6;
-		uport->iotype = new_serial.io_type;
-		uport->regshift = new_serial.iomem_reg_shift;
-		uport->mapbase = (unsigned long)new_serial.iomem_base;
+		uport->type = new_info->type;
+		uport->hub6 = new_info->hub6;
+		uport->iotype = new_info->io_type;
+		uport->regshift = new_info->iomem_reg_shift;
+		uport->mapbase = (unsigned long)new_info->iomem_base;
 
 		/*
 		 * Claim and map the new regions
@@ -810,44 +834,46 @@ static int uart_set_info(struct tty_struct *tty, struct uart_state *state,
 		 * If we fail to request resources for the
 		 * new port, try to restore the old settings.
 		 */
-		if (retval && old_type != PORT_UNKNOWN) {
+		if (retval) {
 			uport->iobase = old_iobase;
 			uport->type = old_type;
 			uport->hub6 = old_hub6;
 			uport->iotype = old_iotype;
 			uport->regshift = old_shift;
 			uport->mapbase = old_mapbase;
-			retval = uport->ops->request_port(uport);
-			/*
-			 * If we failed to restore the old settings,
-			 * we fail like this.
-			 */
-			if (retval)
-				uport->type = PORT_UNKNOWN;
 
-			/*
-			 * We failed anyway.
-			 */
-			retval = -EBUSY;
+			if (old_type != PORT_UNKNOWN) {
+				retval = uport->ops->request_port(uport);
+				/*
+				 * If we failed to restore the old settings,
+				 * we fail like this.
+				 */
+				if (retval)
+					uport->type = PORT_UNKNOWN;
+
+				/*
+				 * We failed anyway.
+				 */
+				retval = -EBUSY;
+			}
+
 			/* Added to return the correct error -Ram Gupta */
 			goto exit;
 		}
 	}
 
 	if (change_irq)
-		uport->irq      = new_serial.irq;
+		uport->irq      = new_info->irq;
 	if (!(uport->flags & UPF_FIXED_PORT))
-		uport->uartclk  = new_serial.baud_base * 16;
+		uport->uartclk  = new_info->baud_base * 16;
 	uport->flags            = (uport->flags & ~UPF_CHANGE_MASK) |
 				 (new_flags & UPF_CHANGE_MASK);
-	uport->custom_divisor   = new_serial.custom_divisor;
+	uport->custom_divisor   = new_info->custom_divisor;
 	port->close_delay     = close_delay;
 	port->closing_wait    = closing_wait;
-	if (new_serial.xmit_fifo_size)
-		uport->fifosize = new_serial.xmit_fifo_size;
-	if (port->tty)
-		port->tty->low_latency =
-			(uport->flags & UPF_LOW_LATENCY) ? 1 : 0;
+	if (new_info->xmit_fifo_size)
+		uport->fifosize = new_info->xmit_fifo_size;
+	port->low_latency = (uport->flags & UPF_LOW_LATENCY) ? 1 : 0;
 
  check_and_exit:
 	retval = 0;
@@ -873,6 +899,28 @@ static int uart_set_info(struct tty_struct *tty, struct uart_state *state,
 	} else
 		retval = uart_startup(tty, state, 1);
  exit:
+	return retval;
+}
+
+static int uart_set_info_user(struct tty_struct *tty, struct uart_state *state,
+			 struct serial_struct __user *newinfo)
+{
+	struct serial_struct new_serial;
+	struct tty_port *port = &state->port;
+	int retval;
+
+	if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
+		return -EFAULT;
+
+	/*
+	 * This semaphore protects port->count.  It is also
+	 * very useful to prevent opens.  Also, take the
+	 * port configuration semaphore to make sure that a
+	 * module insertion/removal doesn't change anything
+	 * under us.
+	 */
+	mutex_lock(&port->mutex);
+	retval = uart_set_info(tty, port, state, &new_serial);
 	mutex_unlock(&port->mutex);
 	return retval;
 }
@@ -1115,11 +1163,11 @@ uart_ioctl(struct tty_struct *tty, unsigned int cmd,
 	 */
 	switch (cmd) {
 	case TIOCGSERIAL:
-		ret = uart_get_info(state, uarg);
+		ret = uart_get_info_user(port, uarg);
 		break;
 
 	case TIOCSSERIAL:
-		ret = uart_set_info(tty, state, uarg);
+		ret = uart_set_info_user(tty, state, uarg);
 		break;
 
 	case TIOCSERCONFIG:
@@ -1187,16 +1235,29 @@ static void uart_set_ldisc(struct tty_struct *tty)
 	struct uart_port *uport = state->uart_port;
 
 	if (uport->ops->set_ldisc)
-		uport->ops->set_ldisc(uport, tty->termios->c_line);
+		uport->ops->set_ldisc(uport, tty->termios.c_line);
 }
 
 static void uart_set_termios(struct tty_struct *tty,
 						struct ktermios *old_termios)
 {
 	struct uart_state *state = tty->driver_data;
+	struct uart_port *uport = state->uart_port;
 	unsigned long flags;
-	unsigned int cflag = tty->termios->c_cflag;
+	unsigned int cflag = tty->termios.c_cflag;
+	unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
+	bool sw_changed = false;
 
+	/*
+	 * Drivers doing software flow control also need to know
+	 * about changes to these input settings.
+	 */
+	if (uport->flags & UPF_SOFT_FLOW) {
+		iflag_mask |= IXANY|IXON|IXOFF;
+		sw_changed =
+		   tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
+		   tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
+	}
 
 	/*
 	 * These are the bits that are used to setup various
@@ -1204,11 +1265,11 @@ static void uart_set_termios(struct tty_struct *tty,
 	 * bits in c_cflag; c_[io]speed will always be set
 	 * appropriately by set_termios() in tty_ioctl.c
 	 */
-#define RELEVANT_IFLAG(iflag)	((iflag) & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))
 	if ((cflag ^ old_termios->c_cflag) == 0 &&
-	    tty->termios->c_ospeed == old_termios->c_ospeed &&
-	    tty->termios->c_ispeed == old_termios->c_ispeed &&
-	    RELEVANT_IFLAG(tty->termios->c_iflag ^ old_termios->c_iflag) == 0) {
+	    tty->termios.c_ospeed == old_termios->c_ospeed &&
+	    tty->termios.c_ispeed == old_termios->c_ispeed &&
+	    ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
+	    !sw_changed) {
 		return;
 	}
 
@@ -1216,38 +1277,46 @@ static void uart_set_termios(struct tty_struct *tty,
 
 	/* Handle transition to B0 status */
 	if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
-		uart_clear_mctrl(state->uart_port, TIOCM_RTS | TIOCM_DTR);
+		uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
 	/* Handle transition away from B0 status */
 	else if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
 		unsigned int mask = TIOCM_DTR;
 		if (!(cflag & CRTSCTS) ||
 		    !test_bit(TTY_THROTTLED, &tty->flags))
 			mask |= TIOCM_RTS;
-		uart_set_mctrl(state->uart_port, mask);
+		uart_set_mctrl(uport, mask);
 	}
 
+	/*
+	 * If the port is doing h/w assisted flow control, do nothing.
+	 * We assume that tty->hw_stopped has never been set.
+	 */
+	if (uport->flags & UPF_HARD_FLOW)
+		return;
+
 	/* Handle turning off CRTSCTS */
 	if ((old_termios->c_cflag & CRTSCTS) && !(cflag & CRTSCTS)) {
-		spin_lock_irqsave(&state->uart_port->lock, flags);
+		spin_lock_irqsave(&uport->lock, flags);
 		tty->hw_stopped = 0;
 		__uart_start(tty);
-		spin_unlock_irqrestore(&state->uart_port->lock, flags);
+		spin_unlock_irqrestore(&uport->lock, flags);
 	}
 	/* Handle turning on CRTSCTS */
 	else if (!(old_termios->c_cflag & CRTSCTS) && (cflag & CRTSCTS)) {
-		spin_lock_irqsave(&state->uart_port->lock, flags);
-		if (!(state->uart_port->ops->get_mctrl(state->uart_port) & TIOCM_CTS)) {
+		spin_lock_irqsave(&uport->lock, flags);
+		if (!(uport->ops->get_mctrl(uport) & TIOCM_CTS)) {
 			tty->hw_stopped = 1;
-			state->uart_port->ops->stop_tx(state->uart_port);
+			uport->ops->stop_tx(uport);
 		}
-		spin_unlock_irqrestore(&state->uart_port->lock, flags);
+		spin_unlock_irqrestore(&uport->lock, flags);
 	}
 }
 
 /*
- * In 2.4.5, calls to this will be serialized via the BKL in
- *  linux/drivers/char/tty_io.c:tty_release()
- *  linux/drivers/char/tty_io.c:do_tty_handup()
+ * Calls to uart_close() are serialised via the tty_lock in
+ *   drivers/tty/tty_io.c:tty_release()
+ *   drivers/tty/tty_io.c:do_tty_hangup()
+ * This runs from a workqueue and can sleep for a _short_ time only.
  */
 static void uart_close(struct tty_struct *tty, struct file *filp)
 {
@@ -1262,9 +1331,9 @@ static void uart_close(struct tty_struct *tty, struct file *filp)
 	uport = state->uart_port;
 	port = &state->port;
 
-	pr_debug("uart_close(%d) called\n", uport->line);
+	pr_debug("uart_close(%d) called\n", uport ? uport->line : -1);
 
-	if (tty_port_close_start(port, tty, filp) == 0)
+	if (!port->count || tty_port_close_start(port, tty, filp) == 0)
 		return;
 
 	/*
@@ -1302,7 +1371,7 @@ static void uart_close(struct tty_struct *tty, struct file *filp)
 		spin_lock_irqsave(&port->lock, flags);
 	} else if (!uart_console(uport)) {
 		spin_unlock_irqrestore(&port->lock, flags);
-		uart_change_pm(state, 3);
+		uart_change_pm(state, UART_PM_STATE_OFF);
 		spin_lock_irqsave(&port->lock, flags);
 	}
 
@@ -1374,10 +1443,9 @@ static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
 }
 
 /*
- * This is called with the BKL held in
- *  linux/drivers/char/tty_io.c:do_tty_hangup()
- * We're called from the eventd thread, so we can sleep for
- * a _short_ time only.
+ * Calls to uart_hangup() are serialised by the tty_lock in
+ *   drivers/tty/tty_io.c:do_tty_hangup()
+ * This runs from a workqueue and can sleep for a _short_ time only.
  */
 static void uart_hangup(struct tty_struct *tty)
 {
@@ -1396,6 +1464,8 @@ static void uart_hangup(struct tty_struct *tty)
 		clear_bit(ASYNCB_NORMAL_ACTIVE, &port->flags);
 		spin_unlock_irqrestore(&port->lock, flags);
 		tty_port_tty_set(port, NULL);
+		if (!uart_console(state->uart_port))
+			uart_change_pm(state, UART_PM_STATE_OFF);
 		wake_up_interruptible(&port->open_wait);
 		wake_up_interruptible(&port->delta_msr_wait);
 	}
@@ -1458,8 +1528,8 @@ static void uart_dtr_rts(struct tty_port *port, int onoff)
 }
 
 /*
- * calls to uart_open are serialised by the BKL in
- *   fs/char_dev.c:chrdev_open()
+ * Calls to uart_open are serialised by the tty_lock in
+ *   drivers/tty/tty_io.c:tty_open()
  * Note that if this fails, then uart_close() _will_ be called.
  *
  * In time, we want to scrap the "opening nonpresent ports"
@@ -1501,7 +1571,8 @@ static int uart_open(struct tty_struct *tty, struct file *filp)
 	 */
 	tty->driver_data = state;
 	state->uart_port->state = state;
-	tty->low_latency = (state->uart_port->flags & UPF_LOW_LATENCY) ? 1 : 0;
+	state->port.low_latency =
+		(state->uart_port->flags & UPF_LOW_LATENCY) ? 1 : 0;
 	tty_port_tty_set(port, tty);
 
 	/*
@@ -1513,12 +1584,6 @@ static int uart_open(struct tty_struct *tty, struct file *filp)
 	}
 
 	/*
-	 * Make sure the device is in D0 state.
-	 */
-	if (port->count == 1)
-		uart_change_pm(state, 0);
-
-	/*
 	 * Start up the serial port.
 	 */
 	retval = uart_startup(tty, state, 0);
@@ -1557,7 +1622,7 @@ static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
 {
 	struct uart_state *state = drv->state + i;
 	struct tty_port *port = &state->port;
-	int pm_state;
+	enum uart_pm_state pm_state;
 	struct uart_port *uport = state->uart_port;
 	char stat_buf[32];
 	unsigned int status;
@@ -1582,12 +1647,12 @@ static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
 	if (capable(CAP_SYS_ADMIN)) {
 		mutex_lock(&port->mutex);
 		pm_state = state->pm_state;
-		if (pm_state)
-			uart_change_pm(state, 0);
+		if (pm_state != UART_PM_STATE_ON)
+			uart_change_pm(state, UART_PM_STATE_ON);
 		spin_lock_irq(&uport->lock);
 		status = uport->ops->get_mctrl(uport);
 		spin_unlock_irq(&uport->lock);
-		if (pm_state)
+		if (pm_state != UART_PM_STATE_ON)
 			uart_change_pm(state, pm_state);
 		mutex_unlock(&port->mutex);
 
@@ -1648,7 +1713,7 @@ static int uart_proc_show(struct seq_file *m, void *v)
 
 static int uart_proc_open(struct inode *inode, struct file *file)
 {
-	return single_open(file, uart_proc_show, PDE(inode)->data);
+	return single_open(file, uart_proc_show, PDE_DATA(inode));
 }
 
 static const struct file_operations uart_proc_fops = {
@@ -1705,7 +1770,7 @@ uart_get_console(struct uart_port *ports, int nr, struct console *co)
 }
 
 /**
- *	uart_parse_options - Parse serial port baud/parity/bits/flow contro.
+ *	uart_parse_options - Parse serial port baud/parity/bits/flow control.
  *	@options: pointer to option string
  *	@baud: pointer to an 'int' variable for the baud rate.
  *	@parity: pointer to an 'int' variable for the parity.
@@ -1773,9 +1838,13 @@ uart_set_options(struct uart_port *port, struct console *co,
 	/*
 	 * Ensure that the serial console lock is initialised
 	 * early.
+	 * If this port is a console, then the spinlock is already
+	 * initialised.
 	 */
-	spin_lock_init(&port->lock);
-	lockdep_set_class(&port->lock, &port_lock_key);
+	if (!(uart_console(port) && (port->cons->flags & CON_ENABLED))) {
+		spin_lock_init(&port->lock);
+		lockdep_set_class(&port->lock, &port_lock_key);
+	}
 
 	memset(&termios, 0, sizeof(struct ktermios));
 
@@ -1834,7 +1903,8 @@ EXPORT_SYMBOL_GPL(uart_set_options);
  *
  * Locking: port->mutex has to be held
  */
-static void uart_change_pm(struct uart_state *state, int pm_state)
+static void uart_change_pm(struct uart_state *state,
+			   enum uart_pm_state pm_state)
 {
 	struct uart_port *port = state->uart_port;
 
@@ -1877,6 +1947,8 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
 		mutex_unlock(&port->mutex);
 		return 0;
 	}
+	put_device(tty_dev);
+
 	if (console_suspend_enabled || !uart_console(uport))
 		uport->suspended = 1;
 
@@ -1919,7 +1991,7 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
 		console_stop(uport->cons);
 
 	if (console_suspend_enabled || !uart_console(uport))
-		uart_change_pm(state, 3);
+		uart_change_pm(state, UART_PM_STATE_OFF);
 
 	mutex_unlock(&port->mutex);
 
@@ -1942,9 +2014,11 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
 			disable_irq_wake(uport->irq);
 			uport->irq_wake = 0;
 		}
+		put_device(tty_dev);
 		mutex_unlock(&port->mutex);
 		return 0;
 	}
+	put_device(tty_dev);
 	uport->suspended = 0;
 
 	/*
@@ -1960,11 +2034,11 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
 		/*
 		 * If that's unset, use the tty termios setting.
 		 */
-		if (port->tty && port->tty->termios && termios.c_cflag == 0)
-			termios = *(port->tty->termios);
+		if (port->tty && termios.c_cflag == 0)
+			termios = port->tty->termios;
 
 		if (console_suspend_enabled)
-			uart_change_pm(state, 0);
+			uart_change_pm(state, UART_PM_STATE_ON);
 		uport->ops->set_termios(uport, &termios, NULL);
 		if (console_suspend_enabled)
 			console_start(uport->cons);
@@ -1974,7 +2048,7 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
 		const struct uart_ops *ops = uport->ops;
 		int ret;
 
-		uart_change_pm(state, 0);
+		uart_change_pm(state, UART_PM_STATE_ON);
 		spin_lock_irq(&uport->lock);
 		ops->set_mctrl(uport, 0);
 		spin_unlock_irq(&uport->lock);
@@ -2033,12 +2107,12 @@ uart_report_port(struct uart_driver *drv, struct uart_port *port)
 		break;
 	}
 
-	printk(KERN_INFO "%s%s%s%d at %s (irq = %d) is a %s\n",
+	printk(KERN_INFO "%s%s%s%d at %s (irq = %d, base_baud = %d) is a %s\n",
 	       port->dev ? dev_name(port->dev) : "",
 	       port->dev ? ": " : "",
 	       drv->dev_name,
 	       drv->tty_driver->name_base + port->line,
-	       address, port->irq, uart_type(port));
+	       address, port->irq, port->uartclk / 16, uart_type(port));
 }
 
 static void
@@ -2074,7 +2148,7 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,
 		uart_report_port(drv, port);
 
 		/* Power up port for set_mctrl() */
-		uart_change_pm(state, 0);
+		uart_change_pm(state, UART_PM_STATE_ON);
 
 		/*
 		 * Ensure that the modem control lines are de-activated.
@@ -2098,7 +2172,7 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,
 		 * console if we have one.
 		 */
 		if (!uart_console(port))
-			uart_change_pm(state, 3);
+			uart_change_pm(state, UART_PM_STATE_OFF);
 	}
 }
 
@@ -2113,6 +2187,7 @@ static int uart_poll_init(struct tty_driver *driver, int line, char *options)
 	int bits = 8;
 	int parity = 'n';
 	int flow = 'n';
+	int ret;
 
 	if (!state || !state->uart_port)
 		return -1;
@@ -2121,6 +2196,22 @@ static int uart_poll_init(struct tty_driver *driver, int line, char *options)
 	if (!(port->ops->poll_get_char && port->ops->poll_put_char))
 		return -1;
 
+	if (port->ops->poll_init) {
+		struct tty_port *tport = &state->port;
+
+		ret = 0;
+		mutex_lock(&tport->mutex);
+		/*
+		 * We don't set ASYNCB_INITIALIZED as we only initialized the
+		 * hw, e.g. state->xmit is still uninitialized.
+		 */
+		if (!test_bit(ASYNCB_INITIALIZED, &tport->flags))
+			ret = port->ops->poll_init(port);
+		mutex_unlock(&tport->mutex);
+		if (ret)
+			return ret;
+	}
+
 	if (options) {
 		uart_parse_options(options, &baud, &parity, &bits, &flow);
 		return uart_set_options(port, NULL, baud, parity, bits, flow);
@@ -2152,6 +2243,9 @@ static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
 		return;
 
 	port = state->uart_port;
+
+	if (ch == '\n')
+		port->ops->poll_put_char(port, '\r');
 	port->ops->poll_put_char(port, ch);
 }
 #endif
@@ -2260,6 +2354,8 @@ int uart_register_driver(struct uart_driver *drv)
 	if (retval >= 0)
 		return retval;
 
+	for (i = 0; i < drv->nr; i++)
+		tty_port_destroy(&drv->state[i].port);
 	put_tty_driver(normal);
 out_kfree:
 	kfree(drv->state);
@@ -2279,8 +2375,12 @@ out:
 void uart_unregister_driver(struct uart_driver *drv)
 {
 	struct tty_driver *p = drv->tty_driver;
+	unsigned int i;
+
 	tty_unregister_driver(p);
 	put_tty_driver(p);
+	for (i = 0; i < drv->nr; i++)
+		tty_port_destroy(&drv->state[i].port);
 	kfree(drv->state);
 	drv->state = NULL;
 	drv->tty_driver = NULL;
@@ -2293,6 +2393,182 @@ struct tty_driver *uart_console_device(struct console *co, int *index)
 	return p->tty_driver;
 }
 
+static ssize_t uart_get_attr_uartclk(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct serial_struct tmp;
+	struct tty_port *port = dev_get_drvdata(dev);
+
+	uart_get_info(port, &tmp);
+	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.baud_base * 16);
+}
+
+static ssize_t uart_get_attr_type(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct serial_struct tmp;
+	struct tty_port *port = dev_get_drvdata(dev);
+
+	uart_get_info(port, &tmp);
+	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.type);
+}
+static ssize_t uart_get_attr_line(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct serial_struct tmp;
+	struct tty_port *port = dev_get_drvdata(dev);
+
+	uart_get_info(port, &tmp);
+	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.line);
+}
+
+static ssize_t uart_get_attr_port(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct serial_struct tmp;
+	struct tty_port *port = dev_get_drvdata(dev);
+	unsigned long ioaddr;
+
+	uart_get_info(port, &tmp);
+	ioaddr = tmp.port;
+	if (HIGH_BITS_OFFSET)
+		ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
+	return snprintf(buf, PAGE_SIZE, "0x%lX\n", ioaddr);
+}
+
+static ssize_t uart_get_attr_irq(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct serial_struct tmp;
+	struct tty_port *port = dev_get_drvdata(dev);
+
+	uart_get_info(port, &tmp);
+	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.irq);
+}
+
+static ssize_t uart_get_attr_flags(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct serial_struct tmp;
+	struct tty_port *port = dev_get_drvdata(dev);
+
+	uart_get_info(port, &tmp);
+	return snprintf(buf, PAGE_SIZE, "0x%X\n", tmp.flags);
+}
+
+static ssize_t uart_get_attr_xmit_fifo_size(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct serial_struct tmp;
+	struct tty_port *port = dev_get_drvdata(dev);
+
+	uart_get_info(port, &tmp);
+	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.xmit_fifo_size);
+}
+
+
+static ssize_t uart_get_attr_close_delay(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct serial_struct tmp;
+	struct tty_port *port = dev_get_drvdata(dev);
+
+	uart_get_info(port, &tmp);
+	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.close_delay);
+}
+
+
+static ssize_t uart_get_attr_closing_wait(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct serial_struct tmp;
+	struct tty_port *port = dev_get_drvdata(dev);
+
+	uart_get_info(port, &tmp);
+	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.closing_wait);
+}
+
+static ssize_t uart_get_attr_custom_divisor(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct serial_struct tmp;
+	struct tty_port *port = dev_get_drvdata(dev);
+
+	uart_get_info(port, &tmp);
+	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.custom_divisor);
+}
+
+static ssize_t uart_get_attr_io_type(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct serial_struct tmp;
+	struct tty_port *port = dev_get_drvdata(dev);
+
+	uart_get_info(port, &tmp);
+	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.io_type);
+}
+
+static ssize_t uart_get_attr_iomem_base(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct serial_struct tmp;
+	struct tty_port *port = dev_get_drvdata(dev);
+
+	uart_get_info(port, &tmp);
+	return snprintf(buf, PAGE_SIZE, "0x%lX\n", (unsigned long)tmp.iomem_base);
+}
+
+static ssize_t uart_get_attr_iomem_reg_shift(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct serial_struct tmp;
+	struct tty_port *port = dev_get_drvdata(dev);
+
+	uart_get_info(port, &tmp);
+	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.iomem_reg_shift);
+}
+
+static DEVICE_ATTR(type, S_IRUSR | S_IRGRP, uart_get_attr_type, NULL);
+static DEVICE_ATTR(line, S_IRUSR | S_IRGRP, uart_get_attr_line, NULL);
+static DEVICE_ATTR(port, S_IRUSR | S_IRGRP, uart_get_attr_port, NULL);
+static DEVICE_ATTR(irq, S_IRUSR | S_IRGRP, uart_get_attr_irq, NULL);
+static DEVICE_ATTR(flags, S_IRUSR | S_IRGRP, uart_get_attr_flags, NULL);
+static DEVICE_ATTR(xmit_fifo_size, S_IRUSR | S_IRGRP, uart_get_attr_xmit_fifo_size, NULL);
+static DEVICE_ATTR(uartclk, S_IRUSR | S_IRGRP, uart_get_attr_uartclk, NULL);
+static DEVICE_ATTR(close_delay, S_IRUSR | S_IRGRP, uart_get_attr_close_delay, NULL);
+static DEVICE_ATTR(closing_wait, S_IRUSR | S_IRGRP, uart_get_attr_closing_wait, NULL);
+static DEVICE_ATTR(custom_divisor, S_IRUSR | S_IRGRP, uart_get_attr_custom_divisor, NULL);
+static DEVICE_ATTR(io_type, S_IRUSR | S_IRGRP, uart_get_attr_io_type, NULL);
+static DEVICE_ATTR(iomem_base, S_IRUSR | S_IRGRP, uart_get_attr_iomem_base, NULL);
+static DEVICE_ATTR(iomem_reg_shift, S_IRUSR | S_IRGRP, uart_get_attr_iomem_reg_shift, NULL);
+
+static struct attribute *tty_dev_attrs[] = {
+	&dev_attr_type.attr,
+	&dev_attr_line.attr,
+	&dev_attr_port.attr,
+	&dev_attr_irq.attr,
+	&dev_attr_flags.attr,
+	&dev_attr_xmit_fifo_size.attr,
+	&dev_attr_uartclk.attr,
+	&dev_attr_close_delay.attr,
+	&dev_attr_closing_wait.attr,
+	&dev_attr_custom_divisor.attr,
+	&dev_attr_io_type.attr,
+	&dev_attr_iomem_base.attr,
+	&dev_attr_iomem_reg_shift.attr,
+	NULL,
+	};
+
+static const struct attribute_group tty_dev_attr_group = {
+	.attrs = tty_dev_attrs,
+	};
+
+static const struct attribute_group *tty_dev_attr_groups[] = {
+	&tty_dev_attr_group,
+	NULL
+	};
+
+
 /**
  *	uart_add_one_port - attach a driver-defined port structure
  *	@drv: pointer to the uart low level driver structure for this port
@@ -2326,7 +2602,7 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
 	}
 
 	state->uart_port = uport;
-	state->pm_state = -1;
+	state->pm_state = UART_PM_STATE_UNDEFINED;
 
 	uport->cons = drv->cons;
 	uport->state = state;
@@ -2344,9 +2620,10 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
 
 	/*
 	 * Register the port whether it's detected or not.  This allows
-	 * setserial to be used to alter this ports parameters.
+	 * setserial to be used to alter this port's parameters.
 	 */
-	tty_dev = tty_register_device(drv->tty_driver, uport->line, uport->dev);
+	tty_dev = tty_port_register_device_attr(port, drv->tty_driver,
+			uport->line, uport->dev, port, tty_dev_attr_groups);
 	if (likely(!IS_ERR(tty_dev))) {
 		device_set_wakeup_capable(tty_dev, 1);
 	} else {
@@ -2379,6 +2656,8 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
 {
 	struct uart_state *state = drv->state + uport->line;
 	struct tty_port *port = &state->port;
+	struct tty_struct *tty;
+	int ret = 0;
 
 	BUG_ON(in_interrupt());
 
@@ -2393,6 +2672,11 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
 	 * succeeding while we shut down the port.
 	 */
 	mutex_lock(&port->mutex);
+	if (!state->uart_port) {
+		mutex_unlock(&port->mutex);
+		ret = -EINVAL;
+		goto out;
+	}
 	uport->flags |= UPF_DEAD;
 	mutex_unlock(&port->mutex);
 
@@ -2401,8 +2685,17 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
 	 */
 	tty_unregister_device(drv->tty_driver, uport->line);
 
-	if (port->tty)
+	tty = tty_port_tty_get(port);
+	if (tty) {
 		tty_vhangup(port->tty);
+		tty_kref_put(tty);
+	}
+
+	/*
+	 * If the port is used as a console, unregister it
+	 */
+	if (uart_console(uport))
+		unregister_console(uport->cons);
 
 	/*
 	 * Free the port IO and memory resources, if any.
@@ -2416,9 +2709,10 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
 	uport->type = PORT_UNKNOWN;
 
 	state->uart_port = NULL;
+out:
 	mutex_unlock(&port_mutex);
 
-	return 0;
+	return ret;
 }
 
 /*
@@ -2452,31 +2746,24 @@ EXPORT_SYMBOL(uart_match_port);
  */
 void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
 {
-	struct uart_state *state = uport->state;
-	struct tty_port *port = &state->port;
-	struct tty_ldisc *ld = tty_ldisc_ref(port->tty);
-	struct pps_event_time ts;
+	struct tty_port *port = &uport->state->port;
+	struct tty_struct *tty = port->tty;
+	struct tty_ldisc *ld = tty ? tty_ldisc_ref(tty) : NULL;
 
-	if (ld && ld->ops->dcd_change)
-		pps_get_ts(&ts);
+	if (ld) {
+		if (ld->ops->dcd_change)
+			ld->ops->dcd_change(tty, status);
+		tty_ldisc_deref(ld);
+	}
 
 	uport->icount.dcd++;
-#ifdef CONFIG_HARD_PPS
-	if ((uport->flags & UPF_HARDPPS_CD) && status)
-		hardpps();
-#endif
 
 	if (port->flags & ASYNC_CHECK_CD) {
 		if (status)
 			wake_up_interruptible(&port->open_wait);
-		else if (port->tty)
-			tty_hangup(port->tty);
+		else if (tty)
+			tty_hangup(tty);
 	}
-
-	if (ld && ld->ops->dcd_change)
-		ld->ops->dcd_change(port->tty, status, &ts);
-	if (ld)
-		tty_ldisc_deref(ld);
 }
 EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
 
@@ -2492,7 +2779,9 @@ void uart_handle_cts_change(struct uart_port *uport, unsigned int status)
 
 	uport->icount.cts++;
 
-	if (port->flags & ASYNC_CTS_FLOW) {
+	/* skip below code if the hw flow control is supported */
+	if (tty_port_cts_enabled(port) &&
+	    !(uport->flags & UPF_HARD_FLOW)) {
 		if (tty->hw_stopped) {
 			if (status) {
 				tty->hw_stopped = 0;
@@ -2524,17 +2813,19 @@ EXPORT_SYMBOL_GPL(uart_handle_cts_change);
 void uart_insert_char(struct uart_port *port, unsigned int status,
 		 unsigned int overrun, unsigned int ch, unsigned int flag)
 {
-	struct tty_struct *tty = port->state->port.tty;
+	struct tty_port *tport = &port->state->port;
 
 	if ((status & port->ignore_status_mask & ~overrun) == 0)
-		tty_insert_flip_char(tty, ch, flag);
+		if (tty_insert_flip_char(tport, ch, flag) == 0)
+			++port->icount.buf_overrun;
 
 	/*
 	 * Overrun is special.  Since it's reported immediately,
 	 * it doesn't affect the current character.
 	 */
 	if (status & ~port->ignore_status_mask & overrun)
-		tty_insert_flip_char(tty, 0, TTY_OVERRUN);
+		if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
+			++port->icount.buf_overrun;
 }
 EXPORT_SYMBOL_GPL(uart_insert_char);