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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: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Cox
Greg Kroah-Hartman
parent
0a68f64feb
commit
584abc3775
@ -77,7 +77,6 @@ struct sdio_uart_port {
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struct kref kref;
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struct tty_struct *tty;
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unsigned int index;
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unsigned int opened;
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struct sdio_func *func;
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struct mutex func_lock;
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struct task_struct *in_sdio_uart_irq;
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@ -150,6 +149,7 @@ static void sdio_uart_port_put(struct sdio_uart_port *port)
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static void sdio_uart_port_remove(struct sdio_uart_port *port)
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{
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struct sdio_func *func;
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struct tty_struct *tty;
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BUG_ON(sdio_uart_table[port->index] != port);
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@ -170,11 +170,10 @@ static void sdio_uart_port_remove(struct sdio_uart_port *port)
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sdio_claim_host(func);
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port->func = NULL;
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mutex_unlock(&port->func_lock);
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if (port->opened) {
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struct tty_struct *tty = tty_port_tty_get(&port->port);
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/* tty_hangup is async so is this safe as is ?? */
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if (tty)
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tty_hangup(tty);
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tty = tty_port_tty_get(&port->port);
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/* tty_hangup is async so is this safe as is ?? */
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if (tty) {
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tty_hangup(tty);
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tty_kref_put(tty);
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}
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mutex_unlock(&port->port.mutex);
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@ -560,13 +559,46 @@ static void sdio_uart_irq(struct sdio_func *func)
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port->in_sdio_uart_irq = NULL;
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}
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static int sdio_uart_startup(struct sdio_uart_port *port)
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{
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unsigned long page;
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int ret = -ENOMEM;
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struct tty_struct *tty = tty_port_tty_get(&port->port);
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/**
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* uart_dtr_rts - port helper to set uart signals
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* @tport: tty port to be updated
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* @onoff: set to turn on DTR/RTS
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*
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* Called by the tty port helpers when the modem signals need to be
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* adjusted during an open, close and hangup.
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*/
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/* FIXME: What if it is NULL ?? */
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static void uart_dtr_rts(struct tty_port *tport, int onoff)
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{
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struct sdio_uart_port *port =
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container_of(tport, struct sdio_uart_port, port);
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if (onoff == 0)
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sdio_uart_clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);
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else
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sdio_uart_set_mctrl(port, TIOCM_DTR | TIOCM_RTS);
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}
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/**
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* sdio_uart_activate - start up hardware
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* @tport: tty port to activate
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* @tty: tty bound to this port
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*
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* Activate a tty port. The port locking guarantees us this will be
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* run exactly once per set of opens, and if successful will see the
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* shutdown method run exactly once to match. Start up and shutdown are
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* protected from each other by the internal locking and will not run
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* at the same time even during a hangup event.
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*
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* If we successfully start up the port we take an extra kref as we
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* will keep it around until shutdown when the kref is dropped.
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*/
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static int sdio_uart_activate(struct tty_port *tport, struct tty_struct *tty)
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{
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struct sdio_uart_port *port =
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container_of(tport, struct sdio_uart_port, port);
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unsigned long page;
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int ret;
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/*
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* Set the TTY IO error marker - we will only clear this
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@ -577,7 +609,7 @@ static int sdio_uart_startup(struct sdio_uart_port *port)
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/* Initialise and allocate the transmit buffer. */
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page = __get_free_page(GFP_KERNEL);
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if (!page)
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goto err0;
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return -ENOMEM;
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port->xmit.buf = (unsigned char *)page;
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circ_clear(&port->xmit);
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@ -631,7 +663,6 @@ static int sdio_uart_startup(struct sdio_uart_port *port)
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sdio_uart_irq(port->func);
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sdio_uart_release_func(port);
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tty_kref_put(tty);
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return 0;
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err3:
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@ -640,15 +671,25 @@ err2:
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sdio_uart_release_func(port);
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err1:
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free_page((unsigned long)port->xmit.buf);
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err0:
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tty_kref_put(tty);
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return ret;
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}
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static void sdio_uart_shutdown(struct sdio_uart_port *port)
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/**
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* sdio_uart_shutdown - stop hardware
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* @tport: tty port to shut down
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*
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* Deactivate a tty port. The port locking guarantees us this will be
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* run only if a successful matching activate already ran. The two are
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* protected from each other by the internal locking and will not run
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* at the same time even during a hangup event.
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*/
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static void sdio_uart_shutdown(struct tty_port *tport)
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{
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struct sdio_uart_port *port =
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container_of(tport, struct sdio_uart_port, port);
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int ret;
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struct tty_struct *tty;
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ret = sdio_uart_claim_func(port);
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if (ret)
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@ -656,14 +697,6 @@ static void sdio_uart_shutdown(struct sdio_uart_port *port)
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sdio_uart_stop_rx(port);
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/* TODO: wait here for TX FIFO to drain */
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tty = tty_port_tty_get(&port->port);
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/* Turn off DTR and RTS early. */
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if (tty && (tty->termios->c_cflag & HUPCL))
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sdio_uart_clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);
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tty_kref_put(tty);
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/* Disable interrupts from this port */
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sdio_release_irq(port->func);
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port->ier = 0;
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@ -688,74 +721,68 @@ skip:
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free_page((unsigned long)port->xmit.buf);
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}
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/**
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* sdio_uart_install - install method
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* @driver: the driver in use (sdio_uart in our case)
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* @tty: the tty being bound
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*
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* Look up and bind the tty and the driver together. Initialize
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* any needed private data (in our case the termios)
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*/
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static int sdio_uart_install(struct tty_driver *driver, struct tty_struct *tty)
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{
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int idx = tty->index;
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struct sdio_uart_port *port = sdio_uart_port_get(idx);
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int ret = tty_init_termios(tty);
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if (ret == 0) {
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tty_driver_kref_get(driver);
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tty->count++;
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/* This is the ref sdio_uart_port get provided */
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tty->driver_data = port;
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driver->ttys[idx] = tty;
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} else
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sdio_uart_port_put(port);
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return ret;
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}
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/**
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* sdio_uart_cleanup - called on the last tty kref drop
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* @tty: the tty being destroyed
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*
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* Called asynchronously when the last reference to the tty is dropped.
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* We cannot destroy the tty->driver_data port kref until this point
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*/
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static void sdio_uart_cleanup(struct tty_struct *tty)
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{
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struct sdio_uart_port *port = tty->driver_data;
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tty->driver_data = NULL; /* Bug trap */
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sdio_uart_port_put(port);
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}
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/*
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* Open/close/hangup is now entirely boilerplate
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*/
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static int sdio_uart_open(struct tty_struct *tty, struct file *filp)
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{
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struct sdio_uart_port *port;
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int ret;
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port = sdio_uart_port_get(tty->index);
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if (!port)
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return -ENODEV;
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mutex_lock(&port->port.mutex);
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/*
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* Make sure not to mess up with a dead port
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* which has not been closed yet.
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*/
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if (tty->driver_data && tty->driver_data != port) {
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mutex_unlock(&port->port.mutex);
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sdio_uart_port_put(port);
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return -EBUSY;
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}
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if (!port->opened) {
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tty->driver_data = port;
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tty_port_tty_set(&port->port, tty);
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ret = sdio_uart_startup(port);
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if (ret) {
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tty->driver_data = NULL;
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tty_port_tty_set(&port->port, NULL);
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mutex_unlock(&port->port.mutex);
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sdio_uart_port_put(port);
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return ret;
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}
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}
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port->opened++;
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mutex_unlock(&port->port.mutex);
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return 0;
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struct sdio_uart_port *port = tty->driver_data;
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return tty_port_open(&port->port, tty, filp);
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}
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static void sdio_uart_close(struct tty_struct *tty, struct file * filp)
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{
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struct sdio_uart_port *port = tty->driver_data;
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tty_port_close(&port->port, tty, filp);
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}
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if (!port)
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return;
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mutex_lock(&port->port.mutex);
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BUG_ON(!port->opened);
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/*
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* This is messy. The tty layer calls us even when open()
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* returned an error. Ignore this close request if tty->count
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* is larger than port->count.
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*/
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if (tty->count > port->opened) {
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mutex_unlock(&port->port.mutex);
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return;
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}
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if (--port->opened == 0) {
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tty->closing = 1;
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sdio_uart_shutdown(port);
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tty_ldisc_flush(tty);
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tty_port_tty_set(&port->port, NULL);
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tty->driver_data = NULL;
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tty->closing = 0;
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}
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mutex_unlock(&port->port.mutex);
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sdio_uart_port_put(port);
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static void sdio_uart_hangup(struct tty_struct *tty)
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{
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struct sdio_uart_port *port = tty->driver_data;
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tty_port_hangup(&port->port);
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}
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static int sdio_uart_write(struct tty_struct * tty, const unsigned char *buf,
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@ -1021,6 +1048,12 @@ static const struct file_operations sdio_uart_proc_fops = {
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.release = single_release,
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};
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static const struct tty_port_operations sdio_uart_port_ops = {
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.dtr_rts = uart_dtr_rts,
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.shutdown = sdio_uart_shutdown,
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.activate = sdio_uart_activate,
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};
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static const struct tty_operations sdio_uart_ops = {
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.open = sdio_uart_open,
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.close = sdio_uart_close,
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@ -1031,9 +1064,12 @@ static const struct tty_operations sdio_uart_ops = {
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.throttle = sdio_uart_throttle,
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.unthrottle = sdio_uart_unthrottle,
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.set_termios = sdio_uart_set_termios,
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.hangup = sdio_uart_hangup,
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.break_ctl = sdio_uart_break_ctl,
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.tiocmget = sdio_uart_tiocmget,
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.tiocmset = sdio_uart_tiocmset,
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.install = sdio_uart_install,
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.cleanup = sdio_uart_cleanup,
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.proc_fops = &sdio_uart_proc_fops,
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};
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@ -1096,6 +1132,7 @@ static int sdio_uart_probe(struct sdio_func *func,
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port->func = func;
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sdio_set_drvdata(func, port);
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tty_port_init(&port->port);
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port->port.ops = &sdio_uart_port_ops;
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ret = sdio_uart_add_port(port);
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if (ret) {
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