1 files changed, 194 insertions, 47 deletions

diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index 33d37d230f8..3f746c8eb0d 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -12,7 +12,6 @@
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
-#include <linux/init.h>
 #include <linux/wait.h>
 #include <linux/bitops.h>
 #include <linux/delay.h>
@@ -21,6 +20,7 @@
 void tty_port_init(struct tty_port *port)
 {
 	memset(port, 0, sizeof(*port));
+	tty_buffer_init(port);
 	init_waitqueue_head(&port->open_wait);
 	init_waitqueue_head(&port->close_wait);
 	init_waitqueue_head(&port->delta_msr_wait);
@@ -33,6 +33,70 @@ void tty_port_init(struct tty_port *port)
 }
 EXPORT_SYMBOL(tty_port_init);
 
+/**
+ * tty_port_link_device - link tty and tty_port
+ * @port: tty_port of the device
+ * @driver: tty_driver for this device
+ * @index: index of the tty
+ *
+ * Provide the tty layer wit ha link from a tty (specified by @index) to a
+ * tty_port (@port). Use this only if neither tty_port_register_device nor
+ * tty_port_install is used in the driver. If used, this has to be called before
+ * tty_register_driver.
+ */
+void tty_port_link_device(struct tty_port *port,
+		struct tty_driver *driver, unsigned index)
+{
+	if (WARN_ON(index >= driver->num))
+		return;
+	driver->ports[index] = port;
+}
+EXPORT_SYMBOL_GPL(tty_port_link_device);
+
+/**
+ * tty_port_register_device - register tty device
+ * @port: tty_port of the device
+ * @driver: tty_driver for this device
+ * @index: index of the tty
+ * @device: parent if exists, otherwise NULL
+ *
+ * It is the same as tty_register_device except the provided @port is linked to
+ * a concrete tty specified by @index. Use this or tty_port_install (or both).
+ * Call tty_port_link_device as a last resort.
+ */
+struct device *tty_port_register_device(struct tty_port *port,
+		struct tty_driver *driver, unsigned index,
+		struct device *device)
+{
+	tty_port_link_device(port, driver, index);
+	return tty_register_device(driver, index, device);
+}
+EXPORT_SYMBOL_GPL(tty_port_register_device);
+
+/**
+ * tty_port_register_device_attr - register tty device
+ * @port: tty_port of the device
+ * @driver: tty_driver for this device
+ * @index: index of the tty
+ * @device: parent if exists, otherwise NULL
+ * @drvdata: Driver data to be set to device.
+ * @attr_grp: Attribute group to be set on device.
+ *
+ * It is the same as tty_register_device_attr except the provided @port is
+ * linked to a concrete tty specified by @index. Use this or tty_port_install
+ * (or both). Call tty_port_link_device as a last resort.
+ */
+struct device *tty_port_register_device_attr(struct tty_port *port,
+		struct tty_driver *driver, unsigned index,
+		struct device *device, void *drvdata,
+		const struct attribute_group **attr_grp)
+{
+	tty_port_link_device(port, driver, index);
+	return tty_register_device_attr(driver, index, device, drvdata,
+			attr_grp);
+}
+EXPORT_SYMBOL_GPL(tty_port_register_device_attr);
+
 int tty_port_alloc_xmit_buf(struct tty_port *port)
 {
 	/* We may sleep in get_zeroed_page() */
@@ -57,12 +121,32 @@ void tty_port_free_xmit_buf(struct tty_port *port)
 }
 EXPORT_SYMBOL(tty_port_free_xmit_buf);
 
+/**
+ * tty_port_destroy -- destroy inited port
+ * @port: tty port to be doestroyed
+ *
+ * When a port was initialized using tty_port_init, one has to destroy the
+ * port by this function. Either indirectly by using tty_port refcounting
+ * (tty_port_put) or directly if refcounting is not used.
+ */
+void tty_port_destroy(struct tty_port *port)
+{
+	cancel_work_sync(&port->buf.work);
+	tty_buffer_free_all(port);
+}
+EXPORT_SYMBOL(tty_port_destroy);
+
 static void tty_port_destructor(struct kref *kref)
 {
 	struct tty_port *port = container_of(kref, struct tty_port, kref);
+
+	/* check if last port ref was dropped before tty release */
+	if (WARN_ON(port->itty))
+		return;
 	if (port->xmit_buf)
 		free_page((unsigned long)port->xmit_buf);
-	if (port->ops->destruct)
+	tty_port_destroy(port);
+	if (port->ops && port->ops->destruct)
 		port->ops->destruct(port);
 	else
 		kfree(port);
@@ -116,12 +200,24 @@ void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty)
 }
 EXPORT_SYMBOL(tty_port_tty_set);
 
-static void tty_port_shutdown(struct tty_port *port)
+static void tty_port_shutdown(struct tty_port *port, struct tty_struct *tty)
 {
 	mutex_lock(&port->mutex);
-	if (port->ops->shutdown && !port->console &&
-		test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags))
+	if (port->console)
+		goto out;
+
+	if (test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags)) {
+		/*
+		 * Drop DTR/RTS if HUPCL is set. This causes any attached
+		 * modem to hang up the line.
+		 */
+		if (tty && C_HUPCL(tty))
+			tty_port_lower_dtr_rts(port);
+
+		if (port->ops->shutdown)
 			port->ops->shutdown(port);
+	}
+out:
 	mutex_unlock(&port->mutex);
 }
 
@@ -135,24 +231,57 @@ static void tty_port_shutdown(struct tty_port *port)
 
 void tty_port_hangup(struct tty_port *port)
 {
+	struct tty_struct *tty;
 	unsigned long flags;
 
 	spin_lock_irqsave(&port->lock, flags);
 	port->count = 0;
 	port->flags &= ~ASYNC_NORMAL_ACTIVE;
-	if (port->tty) {
-		set_bit(TTY_IO_ERROR, &port->tty->flags);
-		tty_kref_put(port->tty);
-	}
+	tty = port->tty;
+	if (tty)
+		set_bit(TTY_IO_ERROR, &tty->flags);
 	port->tty = NULL;
 	spin_unlock_irqrestore(&port->lock, flags);
+	tty_port_shutdown(port, tty);
+	tty_kref_put(tty);
 	wake_up_interruptible(&port->open_wait);
 	wake_up_interruptible(&port->delta_msr_wait);
-	tty_port_shutdown(port);
 }
 EXPORT_SYMBOL(tty_port_hangup);
 
 /**
+ * tty_port_tty_hangup - helper to hang up a tty
+ *
+ * @port: tty port
+ * @check_clocal: hang only ttys with CLOCAL unset?
+ */
+void tty_port_tty_hangup(struct tty_port *port, bool check_clocal)
+{
+	struct tty_struct *tty = tty_port_tty_get(port);
+
+	if (tty && (!check_clocal || !C_CLOCAL(tty)))
+		tty_hangup(tty);
+	tty_kref_put(tty);
+}
+EXPORT_SYMBOL_GPL(tty_port_tty_hangup);
+
+/**
+ * tty_port_tty_wakeup - helper to wake up a tty
+ *
+ * @port: tty port
+ */
+void tty_port_tty_wakeup(struct tty_port *port)
+{
+	struct tty_struct *tty = tty_port_tty_get(port);
+
+	if (tty) {
+		tty_wakeup(tty);
+		tty_kref_put(tty);
+	}
+}
+EXPORT_SYMBOL_GPL(tty_port_tty_wakeup);
+
+/**
  *	tty_port_carrier_raised	-	carrier raised check
  *	@port: tty port
  *
@@ -227,11 +356,10 @@ int tty_port_block_til_ready(struct tty_port *port,
 	int do_clocal = 0, retval;
 	unsigned long flags;
 	DEFINE_WAIT(wait);
-	int cd;
 
 	/* block if port is in the process of being closed */
 	if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
-		wait_event_interruptible_tty(port->close_wait,
+		wait_event_interruptible_tty(tty, port->close_wait,
 				!(port->flags & ASYNC_CLOSING));
 		if (port->flags & ASYNC_HUP_NOTIFY)
 			return -EAGAIN;
@@ -247,7 +375,7 @@ int tty_port_block_til_ready(struct tty_port *port,
 	}
 	if (filp->f_flags & O_NONBLOCK) {
 		/* Indicate we are open */
-		if (tty->termios->c_cflag & CBAUD)
+		if (tty->termios.c_cflag & CBAUD)
 			tty_port_raise_dtr_rts(port);
 		port->flags |= ASYNC_NORMAL_ACTIVE;
 		return 0;
@@ -271,7 +399,7 @@ int tty_port_block_til_ready(struct tty_port *port,
 
 	while (1) {
 		/* Indicate we are open */
-		if (tty->termios->c_cflag & CBAUD)
+		if (C_BAUD(tty) && test_bit(ASYNCB_INITIALIZED, &port->flags))
 			tty_port_raise_dtr_rts(port);
 
 		prepare_to_wait(&port->open_wait, &wait, TASK_INTERRUPTIBLE);
@@ -284,19 +412,22 @@ int tty_port_block_til_ready(struct tty_port *port,
 				retval = -ERESTARTSYS;
 			break;
 		}
-		/* Probe the carrier. For devices with no carrier detect this
-		   will always return true */
-		cd = tty_port_carrier_raised(port);
+		/*
+		 * Probe the carrier. For devices with no carrier detect
+		 * tty_port_carrier_raised will always return true.
+		 * Never ask drivers if CLOCAL is set, this causes troubles
+		 * on some hardware.
+		 */
 		if (!(port->flags & ASYNC_CLOSING) &&
-				(do_clocal || cd))
+				(do_clocal || tty_port_carrier_raised(port)))
 			break;
 		if (signal_pending(current)) {
 			retval = -ERESTARTSYS;
 			break;
 		}
-		tty_unlock();
+		tty_unlock(tty);
 		schedule();
-		tty_lock();
+		tty_lock(tty);
 	}
 	finish_wait(&port->open_wait, &wait);
 
@@ -313,6 +444,20 @@ int tty_port_block_til_ready(struct tty_port *port,
 }
 EXPORT_SYMBOL(tty_port_block_til_ready);
 
+static void tty_port_drain_delay(struct tty_port *port, struct tty_struct *tty)
+{
+	unsigned int bps = tty_get_baud_rate(tty);
+	long timeout;
+
+	if (bps > 1200) {
+		timeout = (HZ * 10 * port->drain_delay) / bps;
+		timeout = max_t(long, timeout, HZ / 10);
+	} else {
+		timeout = 2 * HZ;
+	}
+	schedule_timeout_interruptible(timeout);
+}
+
 int tty_port_close_start(struct tty_port *port,
 				struct tty_struct *tty, struct file *filp)
 {
@@ -338,41 +483,25 @@ int tty_port_close_start(struct tty_port *port,
 
 	if (port->count) {
 		spin_unlock_irqrestore(&port->lock, flags);
-		if (port->ops->drop)
-			port->ops->drop(port);
 		return 0;
 	}
 	set_bit(ASYNCB_CLOSING, &port->flags);
 	tty->closing = 1;
 	spin_unlock_irqrestore(&port->lock, flags);
-	/* Don't block on a stalled port, just pull the chain */
-	if (tty->flow_stopped)
-		tty_driver_flush_buffer(tty);
-	if (test_bit(ASYNCB_INITIALIZED, &port->flags) &&
-			port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
-		tty_wait_until_sent(tty, port->closing_wait);
-	if (port->drain_delay) {
-		unsigned int bps = tty_get_baud_rate(tty);
-		long timeout;
-
-		if (bps > 1200)
-			timeout = max_t(long,
-				(HZ * 10 * port->drain_delay) / bps, HZ / 10);
-		else
-			timeout = 2 * HZ;
-		schedule_timeout_interruptible(timeout);
+
+	if (test_bit(ASYNCB_INITIALIZED, &port->flags)) {
+		/* Don't block on a stalled port, just pull the chain */
+		if (tty->flow_stopped)
+			tty_driver_flush_buffer(tty);
+		if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
+			tty_wait_until_sent_from_close(tty, port->closing_wait);
+		if (port->drain_delay)
+			tty_port_drain_delay(port, tty);
 	}
 	/* Flush the ldisc buffering */
 	tty_ldisc_flush(tty);
 
-	/* Drop DTR/RTS if HUPCL is set. This causes any attached modem to
-	   hang up the line */
-	if (tty->termios->c_cflag & HUPCL)
-		tty_port_lower_dtr_rts(port);
-
-	/* Don't call port->drop for the last reference. Callers will want
-	   to drop the last active reference in ->shutdown() or the tty
-	   shutdown path */
+	/* Report to caller this is the last port reference */
 	return 1;
 }
 EXPORT_SYMBOL(tty_port_close_start);
@@ -404,13 +533,31 @@ void tty_port_close(struct tty_port *port, struct tty_struct *tty,
 {
 	if (tty_port_close_start(port, tty, filp) == 0)
 		return;
-	tty_port_shutdown(port);
+	tty_port_shutdown(port, tty);
 	set_bit(TTY_IO_ERROR, &tty->flags);
 	tty_port_close_end(port, tty);
 	tty_port_tty_set(port, NULL);
 }
 EXPORT_SYMBOL(tty_port_close);
 
+/**
+ * tty_port_install - generic tty->ops->install handler
+ * @port: tty_port of the device
+ * @driver: tty_driver for this device
+ * @tty: tty to be installed
+ *
+ * It is the same as tty_standard_install except the provided @port is linked
+ * to a concrete tty specified by @tty. Use this or tty_port_register_device
+ * (or both). Call tty_port_link_device as a last resort.
+ */
+int tty_port_install(struct tty_port *port, struct tty_driver *driver,
+		struct tty_struct *tty)
+{
+	tty->port = port;
+	return tty_standard_install(driver, tty);
+}
+EXPORT_SYMBOL_GPL(tty_port_install);
+
 int tty_port_open(struct tty_port *port, struct tty_struct *tty,
 							struct file *filp)
 {