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tty_port: Add a port level carrier detect operation

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This is the first step to generalising the various pieces of waiting logic
duplicated in all sorts of serial drivers.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alan Cox
2009-01-02 13:45:05 +00:00
committed by Linus Torvalds
parent c9b3976e3f
commit 31f35939d1
19 changed files with 428 additions and 240 deletions
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26
drivers/char/moxa.c
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@@ -206,6 +206,7 @@ static void moxa_poll(unsigned long);
static void moxa_set_tty_param(struct tty_struct *, struct ktermios *);
static void moxa_setup_empty_event(struct tty_struct *);
static void moxa_shut_down(struct tty_struct *);
static int moxa_carrier_raised(struct tty_port *);
/*
* moxa board interface functions:
*/
@@ -405,6 +406,10 @@ static const struct tty_operations moxa_ops = {
.tiocmset = moxa_tiocmset,
};
static const struct tty_port_operations moxa_port_ops = {
.carrier_raised = moxa_carrier_raised,
};
static struct tty_driver *moxaDriver;
static DEFINE_TIMER(moxaTimer, moxa_poll, 0, 0);
static DEFINE_SPINLOCK(moxa_lock);
@@ -826,6 +831,7 @@ static int moxa_init_board(struct moxa_board_conf *brd, struct device *dev)
for (i = 0, p = brd->ports; i < MAX_PORTS_PER_BOARD; i++, p++) {
tty_port_init(&p->port);
p->port.ops = &moxa_port_ops;
p->type = PORT_16550A;
p->cflag = B9600 | CS8 | CREAD | CLOCAL | HUPCL;
}
@@ -1115,15 +1121,27 @@ static void moxa_close_port(struct tty_struct *tty)
tty_port_tty_set(&ch->port, NULL);
}
static int moxa_carrier_raised(struct tty_port *port)
{
struct moxa_port *ch = container_of(port, struct moxa_port, port);
int dcd;
spin_lock_bh(&moxa_lock);
dcd = ch->DCDState;
spin_unlock_bh(&moxa_lock);
return dcd;
}
static int moxa_block_till_ready(struct tty_struct *tty, struct file *filp,
struct moxa_port *ch)
{
struct tty_port *port = &ch->port;
DEFINE_WAIT(wait);
int retval = 0;
u8 dcd;
while (1) {
prepare_to_wait(&ch->port.open_wait, &wait, TASK_INTERRUPTIBLE);
prepare_to_wait(&port->open_wait, &wait, TASK_INTERRUPTIBLE);
if (tty_hung_up_p(filp)) {
#ifdef SERIAL_DO_RESTART
retval = -ERESTARTSYS;
@@ -1132,9 +1150,7 @@ static int moxa_block_till_ready(struct tty_struct *tty, struct file *filp,
#endif
break;
}
spin_lock_bh(&moxa_lock);
dcd = ch->DCDState;
spin_unlock_bh(&moxa_lock);
dcd = tty_port_carrier_raised(port);
if (dcd)
break;
@@ -1144,7 +1160,7 @@ static int moxa_block_till_ready(struct tty_struct *tty, struct file *filp,
}
schedule();
}
finish_wait(&ch->port.open_wait, &wait);
finish_wait(&port->open_wait, &wait);
return retval;
}