X-Git-Url: http://pilppa.org/gitweb/?a=blobdiff_plain;f=drivers%2Fchar%2Ftty_port.c;h=9b8004c72686a45f6ea577f1cd342e001dbbfa49;hb=c36c63c511fa088fcc247a8e888b04f248be8435;hp=553b0e9d8d17a5513747337ddf5bcf49caaba95b;hpb=b9d7ccf56be1ac77b71a284a1c0e6337f9a7aff0;p=linux-2.6-omap-h63xx.git diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c index 553b0e9d8d1..9b8004c7268 100644 --- a/drivers/char/tty_port.c +++ b/drivers/char/tty_port.c @@ -7,6 +7,7 @@ #include #include #include +#include #include #include #include @@ -90,7 +91,231 @@ void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty) spin_lock_irqsave(&port->lock, flags); if (port->tty) tty_kref_put(port->tty); - port->tty = tty; + port->tty = tty_kref_get(tty); spin_unlock_irqrestore(&port->lock, flags); } EXPORT_SYMBOL(tty_port_tty_set); + +/** + * 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); +} +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 - Riase 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->raise_dtr_rts) + port->ops->raise_dtr_rts(port); +} +EXPORT_SYMBOL(tty_port_raise_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 raise_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; + DECLARE_WAITQUEUE(wait, current); + int cd; + + /* block if port is in the process of being closed */ + if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) { + interruptible_sleep_on(&port->close_wait); + 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; + add_wait_queue(&port->open_wait, &wait); + + /* 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); + + set_current_state(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(); + } + set_current_state(TASK_RUNNING); + remove_wait_queue(&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 0; + +} +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); + return 0; + } + port->flags |= ASYNC_CLOSING; + 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 (port->flags & ASYNC_INITIALIZED && + port->closing_wait != ASYNC_CLOSING_WAIT_NONE) + tty_wait_until_sent(tty, port->closing_wait); + 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); + + 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);