From 3955f605b4722373586dca20401aa2b440de3273 Mon Sep 17 00:00:00 2001
From: Linus Walleij <linus.walleij@stericsson.com>
Date: Wed, 23 Jun 2010 23:32:44 +0200
Subject: [PATCH 54/54] Revert "serial: Use block_til_ready helper"

This reverts commit 34ffc9670d67fe068f9d8582dd4d2a18d9a61205.
---
 drivers/serial/serial_core.c |   87 +++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 86 insertions(+), 1 deletions(-)

diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 78b1eac..ce10627 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1539,6 +1539,91 @@ static void uart_dtr_rts(struct tty_port *port, int onoff)
 		uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
 }
 
+/*
+ * Block the open until the port is ready.  We must be called with
+ * the per-port semaphore held.
+ */
+static int
+uart_block_til_ready(struct file *filp, struct uart_state *state)
+{
+	DECLARE_WAITQUEUE(wait, current);
+	struct tty_port *port = &state->port;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+	if (!tty_hung_up_p(filp))
+		port->count--;
+	port->blocked_open++;
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	add_wait_queue(&port->open_wait, &wait);
+	while (1) {
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		/*
+		 * If we have been hung up, tell userspace/restart open.
+		 */
+		if (tty_hung_up_p(filp) || port->tty == NULL)
+			break;
+
+		/*
+		 * If the port has been closed, tell userspace/restart open.
+		 */
+		if (!(port->flags & ASYNC_INITIALIZED))
+			break;
+
+		/*
+		 * If non-blocking mode is set, or CLOCAL mode is set,
+		 * we don't want to wait for the modem status lines to
+		 * indicate that the port is ready.
+		 *
+		 * Also, if the port is not enabled/configured, we want
+		 * to allow the open to succeed here.  Note that we will
+		 * have set TTY_IO_ERROR for a non-existant port.
+		 */
+		if ((filp->f_flags & O_NONBLOCK) ||
+		    (port->tty->termios->c_cflag & CLOCAL) ||
+		    (port->tty->flags & (1 << TTY_IO_ERROR)))
+			break;
+
+		/*
+		 * Set DTR to allow modem to know we're waiting.  Do
+		 * not set RTS here - we want to make sure we catch
+		 * the data from the modem.
+		 */
+		if (port->tty->termios->c_cflag & CBAUD)
+			tty_port_raise_dtr_rts(port);
+
+		/*
+		 * and wait for the carrier to indicate that the
+		 * modem is ready for us.
+		 */
+		if (tty_port_carrier_raised(port))
+			break;
+
+		schedule();
+
+		if (signal_pending(current))
+			break;
+	}
+	set_current_state(TASK_RUNNING);
+	remove_wait_queue(&port->open_wait, &wait);
+
+	spin_lock_irqsave(&port->lock, flags);
+	if (!tty_hung_up_p(filp))
+		port->count++;
+	port->blocked_open--;
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	if (signal_pending(current))
+		return -ERESTARTSYS;
+
+	if (!port->tty || tty_hung_up_p(filp))
+		return -EAGAIN;
+
+	return 0;
+}
+
 static struct uart_state *uart_get(struct uart_driver *drv, int line)
 {
 	struct uart_state *state;
@@ -1647,7 +1732,7 @@ static int uart_open(struct tty_struct *tty, struct file *filp)
 	 */
 	mutex_unlock(&port->mutex);
 	if (retval == 0)
-		retval = tty_port_block_til_ready(port, tty, filp);
+		retval = uart_block_til_ready(filp, state);
 
 	/*
 	 * If this is the first open to succeed, adjust things to suit.
-- 
1.6.3.3