Commit 584abc37 authored by Alan Cox's avatar Alan Cox Committed by Greg Kroah-Hartman
Browse files

tty: sdio_uart: Switch to the open/close helpers 



Gets us proper tty semantics, removes some code and fixes up a few corner
case races (hangup during open etc)

Signed-off-by: default avatarAlan Cox <alan@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 0a68f64f

drivers/mmc/card/sdio_uart.c

+119 −82
Original line number Diff line number Diff line
@@ -77,7 +77,6 @@ struct sdio_uart_port { 
	struct kref		kref;

	struct tty_struct	*tty;

	unsigned int		index;

	unsigned int		opened;

	struct sdio_func	*func;

	struct mutex		func_lock;

	struct task_struct	*in_sdio_uart_irq;
@@ -150,6 +149,7 @@ static void sdio_uart_port_put(struct sdio_uart_port *port) 
static void sdio_uart_port_remove(struct sdio_uart_port *port)

{

	struct sdio_func *func;

	struct tty_struct *tty;



	BUG_ON(sdio_uart_table[port->index] != port);
@@ -170,10 +170,9 @@ static void sdio_uart_port_remove(struct sdio_uart_port *port) 
	sdio_claim_host(func);

	port->func = NULL;

	mutex_unlock(&port->func_lock);

	if (port->opened) {

		struct tty_struct *tty = tty_port_tty_get(&port->port);

	tty = tty_port_tty_get(&port->port);

	/* tty_hangup is async so is this safe as is ?? */

		if (tty)

	if (tty) {

		tty_hangup(tty);

		tty_kref_put(tty);

	}
@@ -560,13 +559,46 @@ static void sdio_uart_irq(struct sdio_func *func) 
	port->in_sdio_uart_irq = NULL;

}



static int sdio_uart_startup(struct sdio_uart_port *port)

/**

 *	uart_dtr_rts		-	 port helper to set uart signals

 *	@tport: tty port to be updated

 *	@onoff: set to turn on DTR/RTS

 *

 *	Called by the tty port helpers when the modem signals need to be

 *	adjusted during an open, close and hangup.

 */



static void uart_dtr_rts(struct tty_port *tport, int onoff)

{

	unsigned long page;

	int ret = -ENOMEM;

	struct tty_struct *tty = tty_port_tty_get(&port->port);

	struct sdio_uart_port *port =

			container_of(tport, struct sdio_uart_port, port);

	if (onoff == 0)

		sdio_uart_clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);

	else

		sdio_uart_set_mctrl(port, TIOCM_DTR | TIOCM_RTS);

}



	/* FIXME: What if it is NULL ?? */

/**

 *	sdio_uart_activate	-	start up hardware

 *	@tport: tty port to activate

 *	@tty: tty bound to this port

 *

 *	Activate a tty port. The port locking guarantees us this will be

 *	run exactly once per set of opens, and if successful will see the

 *	shutdown method run exactly once to match. Start up and shutdown are

 *	protected from each other by the internal locking and will not run

 *	at the same time even during a hangup event.

 *

 *	If we successfully start up the port we take an extra kref as we

 *	will keep it around until shutdown when the kref is dropped.

 */



static int sdio_uart_activate(struct tty_port *tport, struct tty_struct *tty)

{

	struct sdio_uart_port *port =

			container_of(tport, struct sdio_uart_port, port);

	unsigned long page;

	int ret;



	/*

	 * Set the TTY IO error marker - we will only clear this
@@ -577,7 +609,7 @@ static int sdio_uart_startup(struct sdio_uart_port *port) 
	/* Initialise and allocate the transmit buffer. */

	page = __get_free_page(GFP_KERNEL);

	if (!page)

		goto err0;

		return -ENOMEM;

	port->xmit.buf = (unsigned char *)page;

	circ_clear(&port->xmit);
@@ -631,7 +663,6 @@ static int sdio_uart_startup(struct sdio_uart_port *port) 
	sdio_uart_irq(port->func);



	sdio_uart_release_func(port);

	tty_kref_put(tty);

	return 0;



err3:
@@ -640,15 +671,25 @@ static int sdio_uart_startup(struct sdio_uart_port *port) 
	sdio_uart_release_func(port);

err1:

	free_page((unsigned long)port->xmit.buf);

err0:

	tty_kref_put(tty);

	return ret;

}



static void sdio_uart_shutdown(struct sdio_uart_port *port)



/**

 *	sdio_uart_shutdown	-	stop hardware

 *	@tport: tty port to shut down

 *

 *	Deactivate a tty port. The port locking guarantees us this will be

 *	run only if a successful matching activate already ran. The two are

 *	protected from each other by the internal locking and will not run

 *	at the same time even during a hangup event.

 */



static void sdio_uart_shutdown(struct tty_port *tport)

{

	struct sdio_uart_port *port =

			container_of(tport, struct sdio_uart_port, port);

	int ret;

	struct tty_struct *tty;



	ret = sdio_uart_claim_func(port);

	if (ret)
@@ -656,14 +697,6 @@ static void sdio_uart_shutdown(struct sdio_uart_port *port) 


	sdio_uart_stop_rx(port);



	/* TODO: wait here for TX FIFO to drain */



	tty = tty_port_tty_get(&port->port);

	/* Turn off DTR and RTS early. */

	if (tty && (tty->termios->c_cflag & HUPCL))

		sdio_uart_clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);

	tty_kref_put(tty);



	/* Disable interrupts from this port */

	sdio_release_irq(port->func);

	port->ier = 0;
@@ -688,74 +721,68 @@ static void sdio_uart_shutdown(struct sdio_uart_port *port) 
	free_page((unsigned long)port->xmit.buf);

}



static int sdio_uart_open(struct tty_struct *tty, struct file *filp)

{

	struct sdio_uart_port *port;

	int ret;



	port = sdio_uart_port_get(tty->index);

	if (!port)

		return -ENODEV;



	mutex_lock(&port->port.mutex);



	/*

	 * Make sure not to mess up with a dead port

	 * which has not been closed yet.

/**

 *	sdio_uart_install	-	install method

 *	@driver: the driver in use (sdio_uart in our case)

 *	@tty: the tty being bound

 *

 *	Look up and bind the tty and the driver together. Initialize

 *	any needed private data (in our case the termios)

 */

	if (tty->driver_data && tty->driver_data != port) {

		mutex_unlock(&port->port.mutex);

		sdio_uart_port_put(port);

		return -EBUSY;

	}



	if (!port->opened) {

static int sdio_uart_install(struct tty_driver *driver, struct tty_struct *tty)

{

	int idx = tty->index;

	struct sdio_uart_port *port = sdio_uart_port_get(idx);

	int ret = tty_init_termios(tty);



	if (ret == 0) {

		tty_driver_kref_get(driver);

		tty->count++;

		/* This is the ref sdio_uart_port get provided */

		tty->driver_data = port;

		tty_port_tty_set(&port->port, tty);

		ret = sdio_uart_startup(port);

		if (ret) {

			tty->driver_data = NULL;

			tty_port_tty_set(&port->port, NULL);

			mutex_unlock(&port->port.mutex);

		driver->ttys[idx] = tty;

	} else

		sdio_uart_port_put(port);

	return ret;

		}

	}

	port->opened++;

	mutex_unlock(&port->port.mutex);

	return 0;



}



static void sdio_uart_close(struct tty_struct *tty, struct file * filp)

/**

 *	sdio_uart_cleanup	-	called on the last tty kref drop

 *	@tty: the tty being destroyed

 *

 *	Called asynchronously when the last reference to the tty is dropped.

 *	We cannot destroy the tty->driver_data port kref until this point

 */



static void sdio_uart_cleanup(struct tty_struct *tty)

{

	struct sdio_uart_port *port = tty->driver_data;



	if (!port)

		return;



	mutex_lock(&port->port.mutex);

	BUG_ON(!port->opened);

	tty->driver_data = NULL;	/* Bug trap */

	sdio_uart_port_put(port);

}



/*

	 * This is messy.  The tty layer calls us even when open()

	 * returned an error.  Ignore this close request if tty->count

	 * is larger than port->count.

 *	Open/close/hangup is now entirely boilerplate

 */

	if (tty->count > port->opened) {

		mutex_unlock(&port->port.mutex);

		return;



static int sdio_uart_open(struct tty_struct *tty, struct file *filp)

{

	struct sdio_uart_port *port = tty->driver_data;

	return tty_port_open(&port->port, tty, filp);

}



	if (--port->opened == 0) {

		tty->closing = 1;

		sdio_uart_shutdown(port);

		tty_ldisc_flush(tty);

		tty_port_tty_set(&port->port, NULL);

		tty->driver_data = NULL;

		tty->closing = 0;

static void sdio_uart_close(struct tty_struct *tty, struct file * filp)

{

	struct sdio_uart_port *port = tty->driver_data;

	tty_port_close(&port->port, tty, filp);

}

	mutex_unlock(&port->port.mutex);

	sdio_uart_port_put(port);



static void sdio_uart_hangup(struct tty_struct *tty)

{

	struct sdio_uart_port *port = tty->driver_data;

	tty_port_hangup(&port->port);

}



static int sdio_uart_write(struct tty_struct * tty, const unsigned char *buf,
@@ -1021,6 +1048,12 @@ static const struct file_operations sdio_uart_proc_fops = { 
	.release	= single_release,

};



static const struct tty_port_operations sdio_uart_port_ops = {

	.dtr_rts = uart_dtr_rts,

	.shutdown = sdio_uart_shutdown,

	.activate = sdio_uart_activate,

};



static const struct tty_operations sdio_uart_ops = {

	.open			= sdio_uart_open,

	.close			= sdio_uart_close,
@@ -1031,9 +1064,12 @@ static const struct tty_operations sdio_uart_ops = { 
	.throttle		= sdio_uart_throttle,

	.unthrottle		= sdio_uart_unthrottle,

	.set_termios		= sdio_uart_set_termios,

	.hangup			= sdio_uart_hangup,

	.break_ctl		= sdio_uart_break_ctl,

	.tiocmget		= sdio_uart_tiocmget,

	.tiocmset		= sdio_uart_tiocmset,

	.install		= sdio_uart_install,

	.cleanup		= sdio_uart_cleanup,

	.proc_fops		= &sdio_uart_proc_fops,

};
@@ -1096,6 +1132,7 @@ static int sdio_uart_probe(struct sdio_func *func, 
	port->func = func;

	sdio_set_drvdata(func, port);

	tty_port_init(&port->port);

	port->port.ops = &sdio_uart_port_ops;



	ret = sdio_uart_add_port(port);

	if (ret) {