[deliverable/linux.git] / drivers / char / tty_port.c

/*
 * Tty port functions
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/timer.h>
#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>
#include <linux/module.h>

void tty_port_init(struct tty_port *port)
{
	memset(port, 0, sizeof(*port));
	init_waitqueue_head(&port->open_wait);
	init_waitqueue_head(&port->close_wait);
	init_waitqueue_head(&port->delta_msr_wait);
	mutex_init(&port->mutex);
	spin_lock_init(&port->lock);
	port->close_delay = (50 * HZ) / 100;
	port->closing_wait = (3000 * HZ) / 100;
}
EXPORT_SYMBOL(tty_port_init);

int tty_port_alloc_xmit_buf(struct tty_port *port)
{
	/* We may sleep in get_zeroed_page() */
	mutex_lock(&port->mutex);
	if (port->xmit_buf == NULL)
		port->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL);
	mutex_unlock(&port->mutex);
	if (port->xmit_buf == NULL)
		return -ENOMEM;
	return 0;
}
EXPORT_SYMBOL(tty_port_alloc_xmit_buf);

void tty_port_free_xmit_buf(struct tty_port *port)
{
	mutex_lock(&port->mutex);
	if (port->xmit_buf != NULL) {
		free_page((unsigned long)port->xmit_buf);
		port->xmit_buf = NULL;
	}
	mutex_unlock(&port->mutex);
}
EXPORT_SYMBOL(tty_port_free_xmit_buf);


/**
 *	tty_port_tty_get	-	get a tty reference
 *	@port: tty port
 *
 *	Return a refcount protected tty instance or NULL if the port is not
 *	associated with a tty (eg due to close or hangup)
 */

struct tty_struct *tty_port_tty_get(struct tty_port *port)
{
	unsigned long flags;
	struct tty_struct *tty;

	spin_lock_irqsave(&port->lock, flags);
	tty = tty_kref_get(port->tty);
	spin_unlock_irqrestore(&port->lock, flags);
	return tty;
}
EXPORT_SYMBOL(tty_port_tty_get);

/**
 *	tty_port_tty_set	-	set the tty of a port
 *	@port: tty port
 *	@tty: the tty
 *
 *	Associate the port and tty pair. Manages any internal refcounts.
 *	Pass NULL to deassociate a port
 */

void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty)
{
	unsigned long flags;

	spin_lock_irqsave(&port->lock, flags);
	if (port->tty)
		tty_kref_put(port->tty);
	port->tty = tty_kref_get(tty);
	spin_unlock_irqrestore(&port->lock, flags);
}
EXPORT_SYMBOL(tty_port_tty_set);

static void tty_port_shutdown(struct tty_port *port)
{
	if (port->ops->shutdown &&
		test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags))
			port->ops->shutdown(port);

}

/**
 *	tty_port_hangup		-	hangup helper
 *	@port: tty port
 *
 *	Perform port level tty hangup flag and count changes. Drop the tty
 *	reference.
 */

void tty_port_hangup(struct tty_port *port)
{
	unsigned long flags;

	spin_lock_irqsave(&port->lock, flags);
	port->count = 0;
	port->flags &= ~ASYNC_NORMAL_ACTIVE;
	if (port->tty)
		tty_kref_put(port->tty);
	port->tty = NULL;
	spin_unlock_irqrestore(&port->lock, flags);
	wake_up_interruptible(&port->open_wait);
	wake_up_interruptible(&port->delta_msr_wait);
	tty_port_shutdown(port);
}
EXPORT_SYMBOL(tty_port_hangup);

/**
 *	tty_port_carrier_raised	-	carrier raised check
 *	@port: tty port
 *
 *	Wrapper for the carrier detect logic. For the moment this is used
 *	to hide some internal details. This will eventually become entirely
 *	internal to the tty port.
 */

int tty_port_carrier_raised(struct tty_port *port)
{
	if (port->ops->carrier_raised == NULL)
		return 1;
	return port->ops->carrier_raised(port);
}
EXPORT_SYMBOL(tty_port_carrier_raised);

/**
 *	tty_port_raise_dtr_rts	-	Raise DTR/RTS
 *	@port: tty port
 *
 *	Wrapper for the DTR/RTS raise logic. For the moment this is used
 *	to hide some internal details. This will eventually become entirely
 *	internal to the tty port.
 */

void tty_port_raise_dtr_rts(struct tty_port *port)
{
	if (port->ops->dtr_rts)
		port->ops->dtr_rts(port, 1);
}
EXPORT_SYMBOL(tty_port_raise_dtr_rts);

/**
 *	tty_port_lower_dtr_rts	-	Lower DTR/RTS
 *	@port: tty port
 *
 *	Wrapper for the DTR/RTS raise logic. For the moment this is used
 *	to hide some internal details. This will eventually become entirely
 *	internal to the tty port.
 */

void tty_port_lower_dtr_rts(struct tty_port *port)
{
	if (port->ops->dtr_rts)
		port->ops->dtr_rts(port, 0);
}
EXPORT_SYMBOL(tty_port_lower_dtr_rts);

/**
 *	tty_port_block_til_ready	-	Waiting logic for tty open
 *	@port: the tty port being opened
 *	@tty: the tty device being bound
 *	@filp: the file pointer of the opener
 *
 *	Implement the core POSIX/SuS tty behaviour when opening a tty device.
 *	Handles:
 *		- hangup (both before and during)
 *		- non blocking open
 *		- rts/dtr/dcd
 *		- signals
 *		- port flags and counts
 *
 *	The passed tty_port must implement the carrier_raised method if it can
 *	do carrier detect and the dtr_rts method if it supports software
 *	management of these lines. Note that the dtr/rts raise is done each
 *	iteration as a hangup may have previously dropped them while we wait.
 */
 
int tty_port_block_til_ready(struct tty_port *port,
				struct tty_struct *tty, struct file *filp)
{
	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(port->close_wait,
				!(port->flags & ASYNC_CLOSING));
		if (port->flags & ASYNC_HUP_NOTIFY)
			return -EAGAIN;
		else
			return -ERESTARTSYS;
	}

	/* if non-blocking mode is set we can pass directly to open unless
	   the port has just hung up or is in another error state */
	if ((filp->f_flags & O_NONBLOCK) ||
			(tty->flags & (1 << TTY_IO_ERROR))) {
		port->flags |= ASYNC_NORMAL_ACTIVE;
		return 0;
	}

	if (C_CLOCAL(tty))
		do_clocal = 1;

	/* Block waiting until we can proceed. We may need to wait for the
	   carrier, but we must also wait for any close that is in progress
	   before the next open may complete */

	retval = 0;

	/* The port lock protects the port counts */
	spin_lock_irqsave(&port->lock, flags);
	if (!tty_hung_up_p(filp))
		port->count--;
	port->blocked_open++;
	spin_unlock_irqrestore(&port->lock, flags);

	while (1) {
		/* Indicate we are open */
		if (tty->termios->c_cflag & CBAUD)
			tty_port_raise_dtr_rts(port);

		prepare_to_wait(&port->open_wait, &wait, TASK_INTERRUPTIBLE);
		/* Check for a hangup or uninitialised port. Return accordingly */
		if (tty_hung_up_p(filp) || !(port->flags & ASYNC_INITIALIZED)) {
			if (port->flags & ASYNC_HUP_NOTIFY)
				retval = -EAGAIN;
			else
				retval = -ERESTARTSYS;
			break;
		}
		/* Probe the carrier. For devices with no carrier detect this
		   will always return true */
		cd = tty_port_carrier_raised(port);
		if (!(port->flags & ASYNC_CLOSING) &&
				(do_clocal || cd))
			break;
		if (signal_pending(current)) {
			retval = -ERESTARTSYS;
			break;
		}
		schedule();
	}
	finish_wait(&port->open_wait, &wait);

	/* Update counts. A parallel hangup will have set count to zero and
	   we must not mess that up further */
	spin_lock_irqsave(&port->lock, flags);
	if (!tty_hung_up_p(filp))
		port->count++;
	port->blocked_open--;
	if (retval == 0)
		port->flags |= ASYNC_NORMAL_ACTIVE;
	spin_unlock_irqrestore(&port->lock, flags);
	return retval;
	
}
EXPORT_SYMBOL(tty_port_block_til_ready);

int tty_port_close_start(struct tty_port *port, struct tty_struct *tty, struct file *filp)
{
	unsigned long flags;

	spin_lock_irqsave(&port->lock, flags);
	if (tty_hung_up_p(filp)) {
		spin_unlock_irqrestore(&port->lock, flags);
		return 0;
	}

	if( tty->count == 1 && port->count != 1) {
		printk(KERN_WARNING
		    "tty_port_close_start: tty->count = 1 port count = %d.\n",
								port->count);
		port->count = 1;
	}
	if (--port->count < 0) {
		printk(KERN_WARNING "tty_port_close_start: count = %d\n",
								port->count);
		port->count = 0;
	}

	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);
	}
	/* 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 */
	return 1;
}
EXPORT_SYMBOL(tty_port_close_start);

void tty_port_close_end(struct tty_port *port, struct tty_struct *tty)
{
	unsigned long flags;

	tty_ldisc_flush(tty);

	if (tty->termios->c_cflag & HUPCL)
		tty_port_lower_dtr_rts(port);

	spin_lock_irqsave(&port->lock, flags);
	tty->closing = 0;

	if (port->blocked_open) {
		spin_unlock_irqrestore(&port->lock, flags);
		if (port->close_delay) {
			msleep_interruptible(
				jiffies_to_msecs(port->close_delay));
		}
		spin_lock_irqsave(&port->lock, flags);
		wake_up_interruptible(&port->open_wait);
	}
	port->flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_CLOSING);
	wake_up_interruptible(&port->close_wait);
	spin_unlock_irqrestore(&port->lock, flags);
}
EXPORT_SYMBOL(tty_port_close_end);

void tty_port_close(struct tty_port *port, struct tty_struct *tty,
							struct file *filp)
{
	if (tty_port_close_start(port, tty, filp) == 0)
		return;
	tty_port_shutdown(port);
	tty_port_close_end(port, tty);
	tty_port_tty_set(port, NULL);
}
EXPORT_SYMBOL(tty_port_close);
Commit	Line	Data
9e48565d AC	1	/*
	2	* Tty port functions
	3	*/
	4
	5	#include <linux/types.h>
	6	#include <linux/errno.h>
	7	#include <linux/tty.h>
	8	#include <linux/tty_driver.h>
	9	#include <linux/tty_flip.h>
3e61696b	10	#include <linux/serial.h>
9e48565d AC	11	#include <linux/timer.h>
	12	#include <linux/string.h>
	13	#include <linux/slab.h>
	14	#include <linux/sched.h>
	15	#include <linux/init.h>
	16	#include <linux/wait.h>
	17	#include <linux/bitops.h>
	18	#include <linux/delay.h>
	19	#include <linux/module.h>
	20
	21	void tty_port_init(struct tty_port *port)
	22	{
	23	memset(port, 0, sizeof(*port));
	24	init_waitqueue_head(&port->open_wait);
	25	init_waitqueue_head(&port->close_wait);
bdc04e31	26	init_waitqueue_head(&port->delta_msr_wait);
9e48565d	27	mutex_init(&port->mutex);
4a90f09b	28	spin_lock_init(&port->lock);
9e48565d AC	29	port->close_delay = (50 * HZ) / 100;
	30	port->closing_wait = (3000 * HZ) / 100;
	31	}
	32	EXPORT_SYMBOL(tty_port_init);
	33
	34	int tty_port_alloc_xmit_buf(struct tty_port *port)
	35	{
	36	/* We may sleep in get_zeroed_page() */
	37	mutex_lock(&port->mutex);
	38	if (port->xmit_buf == NULL)
	39	port->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL);
	40	mutex_unlock(&port->mutex);
	41	if (port->xmit_buf == NULL)
	42	return -ENOMEM;
	43	return 0;
	44	}
	45	EXPORT_SYMBOL(tty_port_alloc_xmit_buf);
	46
	47	void tty_port_free_xmit_buf(struct tty_port *port)
	48	{
	49	mutex_lock(&port->mutex);
	50	if (port->xmit_buf != NULL) {
	51	free_page((unsigned long)port->xmit_buf);
	52	port->xmit_buf = NULL;
	53	}
	54	mutex_unlock(&port->mutex);
	55	}
	56	EXPORT_SYMBOL(tty_port_free_xmit_buf);
	57
	58
4a90f09b AC	59	/**
	60	* tty_port_tty_get - get a tty reference
	61	* @port: tty port
	62	*
	63	* Return a refcount protected tty instance or NULL if the port is not
	64	* associated with a tty (eg due to close or hangup)
	65	*/
	66
	67	struct tty_struct tty_port_tty_get(struct tty_port port)
	68	{
	69	unsigned long flags;
	70	struct tty_struct *tty;
	71
	72	spin_lock_irqsave(&port->lock, flags);
	73	tty = tty_kref_get(port->tty);
	74	spin_unlock_irqrestore(&port->lock, flags);
	75	return tty;
	76	}
	77	EXPORT_SYMBOL(tty_port_tty_get);
	78
	79	/**
	80	* tty_port_tty_set - set the tty of a port
	81	* @port: tty port
	82	* @tty: the tty
	83	*
	84	* Associate the port and tty pair. Manages any internal refcounts.
	85	* Pass NULL to deassociate a port
	86	*/
	87
	88	void tty_port_tty_set(struct tty_port port, struct tty_struct tty)
	89	{
	90	unsigned long flags;
	91
	92	spin_lock_irqsave(&port->lock, flags);
	93	if (port->tty)
	94	tty_kref_put(port->tty);
cb4bca35	95	port->tty = tty_kref_get(tty);
4a90f09b AC	96	spin_unlock_irqrestore(&port->lock, flags);
	97	}
	98	EXPORT_SYMBOL(tty_port_tty_set);
31f35939	99
7ca0ff9a AC	100	static void tty_port_shutdown(struct tty_port *port)
	101	{
	102	if (port->ops->shutdown &&
1f5c13fa	103	test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags))
7ca0ff9a AC	104	port->ops->shutdown(port);
	105
	106	}
	107
3e61696b AC	108	/**
	109	* tty_port_hangup - hangup helper
	110	* @port: tty port
	111	*
	112	* Perform port level tty hangup flag and count changes. Drop the tty
	113	* reference.
	114	*/
	115
	116	void tty_port_hangup(struct tty_port *port)
	117	{
	118	unsigned long flags;
	119
	120	spin_lock_irqsave(&port->lock, flags);
	121	port->count = 0;
	122	port->flags &= ~ASYNC_NORMAL_ACTIVE;
	123	if (port->tty)
	124	tty_kref_put(port->tty);
	125	port->tty = NULL;
	126	spin_unlock_irqrestore(&port->lock, flags);
	127	wake_up_interruptible(&port->open_wait);
bdc04e31	128	wake_up_interruptible(&port->delta_msr_wait);
7ca0ff9a	129	tty_port_shutdown(port);
3e61696b AC	130	}
	131	EXPORT_SYMBOL(tty_port_hangup);
	132
31f35939 AC	133	/**
	134	* tty_port_carrier_raised - carrier raised check
	135	* @port: tty port
	136	*
	137	* Wrapper for the carrier detect logic. For the moment this is used
	138	* to hide some internal details. This will eventually become entirely
	139	* internal to the tty port.
	140	*/
	141
	142	int tty_port_carrier_raised(struct tty_port *port)
	143	{
	144	if (port->ops->carrier_raised == NULL)
	145	return 1;
	146	return port->ops->carrier_raised(port);
	147	}
	148	EXPORT_SYMBOL(tty_port_carrier_raised);
5d951fb4 AC	149
5d951fb4 AC	150	/**
fcc8ac18	151	* tty_port_raise_dtr_rts - Raise DTR/RTS
5d951fb4 AC	152	* @port: tty port
	153	*
	154	* Wrapper for the DTR/RTS raise logic. For the moment this is used
	155	* to hide some internal details. This will eventually become entirely
	156	* internal to the tty port.
	157	*/
	158
	159	void tty_port_raise_dtr_rts(struct tty_port *port)
	160	{
fcc8ac18 AC	161	if (port->ops->dtr_rts)
fcc8ac18 AC	162	port->ops->dtr_rts(port, 1);
5d951fb4 AC	163	}
5d951fb4 AC	164	EXPORT_SYMBOL(tty_port_raise_dtr_rts);
36c621d8	165
fcc8ac18 AC	166	/**
	167	* tty_port_lower_dtr_rts - Lower DTR/RTS
	168	* @port: tty port
	169	*
	170	* Wrapper for the DTR/RTS raise logic. For the moment this is used
	171	* to hide some internal details. This will eventually become entirely
	172	* internal to the tty port.
	173	*/
	174
	175	void tty_port_lower_dtr_rts(struct tty_port *port)
	176	{
	177	if (port->ops->dtr_rts)
	178	port->ops->dtr_rts(port, 0);
	179	}
	180	EXPORT_SYMBOL(tty_port_lower_dtr_rts);
	181
36c621d8 AC	182	/**
	183	* tty_port_block_til_ready - Waiting logic for tty open
	184	* @port: the tty port being opened
	185	* @tty: the tty device being bound
	186	* @filp: the file pointer of the opener
	187	*
	188	* Implement the core POSIX/SuS tty behaviour when opening a tty device.
	189	* Handles:
	190	* - hangup (both before and during)
	191	* - non blocking open
	192	* - rts/dtr/dcd
	193	* - signals
	194	* - port flags and counts
	195	*
	196	* The passed tty_port must implement the carrier_raised method if it can
fcc8ac18	197	* do carrier detect and the dtr_rts method if it supports software
36c621d8 AC	198	* management of these lines. Note that the dtr/rts raise is done each
	199	* iteration as a hangup may have previously dropped them while we wait.
	200	*/
	201
	202	int tty_port_block_til_ready(struct tty_port *port,
	203	struct tty_struct tty, struct file filp)
	204	{
	205	int do_clocal = 0, retval;
	206	unsigned long flags;
6af9a43d	207	DEFINE_WAIT(wait);
36c621d8 AC	208	int cd;
	209
	210	/* block if port is in the process of being closed */
	211	if (tty_hung_up_p(filp) \|\| port->flags & ASYNC_CLOSING) {
5fc5b42a JS	212	wait_event_interruptible(port->close_wait,
5fc5b42a JS	213	!(port->flags & ASYNC_CLOSING));
36c621d8 AC	214	if (port->flags & ASYNC_HUP_NOTIFY)
	215	return -EAGAIN;
	216	else
	217	return -ERESTARTSYS;
	218	}
	219
	220	/* if non-blocking mode is set we can pass directly to open unless
	221	the port has just hung up or is in another error state */
	222	if ((filp->f_flags & O_NONBLOCK) \|\|
	223	(tty->flags & (1 << TTY_IO_ERROR))) {
	224	port->flags \|= ASYNC_NORMAL_ACTIVE;
	225	return 0;
	226	}
	227
	228	if (C_CLOCAL(tty))
	229	do_clocal = 1;
	230
	231	/* Block waiting until we can proceed. We may need to wait for the
	232	carrier, but we must also wait for any close that is in progress
	233	before the next open may complete */
	234
	235	retval = 0;
36c621d8 AC	236
	237	/* The port lock protects the port counts */
	238	spin_lock_irqsave(&port->lock, flags);
	239	if (!tty_hung_up_p(filp))
	240	port->count--;
	241	port->blocked_open++;
	242	spin_unlock_irqrestore(&port->lock, flags);
	243
	244	while (1) {
	245	/* Indicate we are open */
7834909f AC	246	if (tty->termios->c_cflag & CBAUD)
7834909f AC	247	tty_port_raise_dtr_rts(port);
36c621d8	248
3e3b5c08	249	prepare_to_wait(&port->open_wait, &wait, TASK_INTERRUPTIBLE);
36c621d8 AC	250	/* Check for a hangup or uninitialised port. Return accordingly */
	251	if (tty_hung_up_p(filp) \|\| !(port->flags & ASYNC_INITIALIZED)) {
	252	if (port->flags & ASYNC_HUP_NOTIFY)
	253	retval = -EAGAIN;
	254	else
	255	retval = -ERESTARTSYS;
	256	break;
	257	}
	258	/* Probe the carrier. For devices with no carrier detect this
	259	will always return true */
	260	cd = tty_port_carrier_raised(port);
	261	if (!(port->flags & ASYNC_CLOSING) &&
	262	(do_clocal \|\| cd))
	263	break;
	264	if (signal_pending(current)) {
	265	retval = -ERESTARTSYS;
	266	break;
	267	}
	268	schedule();
	269	}
3e3b5c08	270	finish_wait(&port->open_wait, &wait);
36c621d8 AC	271
	272	/* Update counts. A parallel hangup will have set count to zero and
	273	we must not mess that up further */
	274	spin_lock_irqsave(&port->lock, flags);
	275	if (!tty_hung_up_p(filp))
	276	port->count++;
	277	port->blocked_open--;
	278	if (retval == 0)
	279	port->flags \|= ASYNC_NORMAL_ACTIVE;
	280	spin_unlock_irqrestore(&port->lock, flags);
ecc2e05e	281	return retval;
36c621d8 AC	282
	283	}
	284	EXPORT_SYMBOL(tty_port_block_til_ready);
	285
a6614999 AC	286	int tty_port_close_start(struct tty_port port, struct tty_struct tty, struct file *filp)
	287	{
	288	unsigned long flags;
	289
	290	spin_lock_irqsave(&port->lock, flags);
	291	if (tty_hung_up_p(filp)) {
	292	spin_unlock_irqrestore(&port->lock, flags);
	293	return 0;
	294	}
	295
	296	if( tty->count == 1 && port->count != 1) {
	297	printk(KERN_WARNING
	298	"tty_port_close_start: tty->count = 1 port count = %d.\n",
	299	port->count);
	300	port->count = 1;
	301	}
	302	if (--port->count < 0) {
	303	printk(KERN_WARNING "tty_port_close_start: count = %d\n",
	304	port->count);
	305	port->count = 0;
	306	}
	307
	308	if (port->count) {
	309	spin_unlock_irqrestore(&port->lock, flags);
7ca0ff9a AC	310	if (port->ops->drop)
7ca0ff9a AC	311	port->ops->drop(port);
a6614999 AC	312	return 0;
a6614999 AC	313	}
1f5c13fa	314	set_bit(ASYNCB_CLOSING, &port->flags);
a6614999 AC	315	tty->closing = 1;
a6614999 AC	316	spin_unlock_irqrestore(&port->lock, flags);
fba85e01 AC	317	/* Don't block on a stalled port, just pull the chain */
	318	if (tty->flow_stopped)
	319	tty_driver_flush_buffer(tty);
7ca0ff9a	320	if (test_bit(ASYNCB_INITIALIZED, &port->flags) &&
6ed1dbae	321	port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
a6614999	322	tty_wait_until_sent(tty, port->closing_wait);
1ec739be AC	323	if (port->drain_delay) {
	324	unsigned int bps = tty_get_baud_rate(tty);
	325	long timeout;
	326
	327	if (bps > 1200)
	328	timeout = max_t(long, (HZ * 10 * port->drain_delay) / bps,
	329	HZ / 10);
	330	else
	331	timeout = 2 * HZ;
	332	schedule_timeout_interruptible(timeout);
	333	}
7ca0ff9a AC	334	/* Don't call port->drop for the last reference. Callers will want
	335	to drop the last active reference in ->shutdown() or the tty
	336	shutdown path */
a6614999 AC	337	return 1;
	338	}
	339	EXPORT_SYMBOL(tty_port_close_start);
	340
	341	void tty_port_close_end(struct tty_port port, struct tty_struct tty)
	342	{
	343	unsigned long flags;
	344
	345	tty_ldisc_flush(tty);
	346
fcc8ac18 AC	347	if (tty->termios->c_cflag & HUPCL)
	348	tty_port_lower_dtr_rts(port);
	349
a6614999 AC	350	spin_lock_irqsave(&port->lock, flags);
	351	tty->closing = 0;
	352
	353	if (port->blocked_open) {
	354	spin_unlock_irqrestore(&port->lock, flags);
	355	if (port->close_delay) {
	356	msleep_interruptible(
	357	jiffies_to_msecs(port->close_delay));
	358	}
	359	spin_lock_irqsave(&port->lock, flags);
	360	wake_up_interruptible(&port->open_wait);
	361	}
	362	port->flags &= ~(ASYNC_NORMAL_ACTIVE \| ASYNC_CLOSING);
	363	wake_up_interruptible(&port->close_wait);
	364	spin_unlock_irqrestore(&port->lock, flags);
	365	}
	366	EXPORT_SYMBOL(tty_port_close_end);
7ca0ff9a AC	367
	368	void tty_port_close(struct tty_port port, struct tty_struct tty,
	369	struct file *filp)
	370	{
	371	if (tty_port_close_start(port, tty, filp) == 0)
	372	return;
	373	tty_port_shutdown(port);
	374	tty_port_close_end(port, tty);
	375	tty_port_tty_set(port, NULL);
	376	}
	377	EXPORT_SYMBOL(tty_port_close);