lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

tty_port: Add a port level carrier detect operation

Browse Source 
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
Download Patch File Download Diff File Expand all files Collapse all files

43
drivers/char/generic_serial.c
View File

@@ -397,7 +397,8 @@ void gs_hangup(struct tty_struct *tty)
int gs_block_til_ready(void *port_, struct file * filp)
{
struct gs_port *port = port_;
struct gs_port *gp = port_;
struct tty_port *port = &gp->port;
DECLARE_WAITQUEUE(wait, current);
int retval;
int do_clocal = 0;
@@ -409,16 +410,16 @@ int gs_block_til_ready(void *port_, struct file * filp)
if (!port) return 0;
tty = port->port.tty;
tty = port->tty;
gs_dprintk (GS_DEBUG_BTR, "Entering gs_block_till_ready.\n");
/*
* If the device is in the middle of being closed, then block
* until it's done, and then try again.
*/
if (tty_hung_up_p(filp) || port->port.flags & ASYNC_CLOSING) {
interruptible_sleep_on(&port->port.close_wait);
if (port->port.flags & ASYNC_HUP_NOTIFY)
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;
@@ -432,7 +433,7 @@ int gs_block_til_ready(void *port_, struct file * filp)
*/
if ((filp->f_flags & O_NONBLOCK) ||
(tty->flags & (1 << TTY_IO_ERROR))) {
port->port.flags |= ASYNC_NORMAL_ACTIVE;
port->flags |= ASYNC_NORMAL_ACTIVE;
return 0;
}
@@ -444,34 +445,34 @@ int gs_block_til_ready(void *port_, struct file * filp)
/*
* Block waiting for the carrier detect and the line to become
* free (i.e., not in use by the callout). While we are in
* this loop, port->port.count is dropped by one, so that
* this loop, port->count is dropped by one, so that
* rs_close() knows when to free things. We restore it upon
* exit, either normal or abnormal.
*/
retval = 0;
add_wait_queue(&port->port.open_wait, &wait);
add_wait_queue(&port->open_wait, &wait);
gs_dprintk (GS_DEBUG_BTR, "after add waitq.\n");
spin_lock_irqsave(&port->driver_lock, flags);
spin_lock_irqsave(&gp->driver_lock, flags);
if (!tty_hung_up_p(filp)) {
port->port.count--;
port->count--;
}
spin_unlock_irqrestore(&port->driver_lock, flags);
port->port.blocked_open++;
spin_unlock_irqrestore(&gp->driver_lock, flags);
port->blocked_open++;
while (1) {
CD = port->rd->get_CD (port);
CD = tty_port_carrier_raised(port);
gs_dprintk (GS_DEBUG_BTR, "CD is now %d.\n", CD);
set_current_state (TASK_INTERRUPTIBLE);
if (tty_hung_up_p(filp) ||
!(port->port.flags & ASYNC_INITIALIZED)) {
if (port->port.flags & ASYNC_HUP_NOTIFY)
!(port->flags & ASYNC_INITIALIZED)) {
if (port->flags & ASYNC_HUP_NOTIFY)
retval = -EAGAIN;
else
retval = -ERESTARTSYS;
break;
}
if (!(port->port.flags & ASYNC_CLOSING) &&
if (!(port->flags & ASYNC_CLOSING) &&
(do_clocal || CD))
break;
gs_dprintk (GS_DEBUG_BTR, "signal_pending is now: %d (%lx)\n",
@@ -483,17 +484,17 @@ int gs_block_til_ready(void *port_, struct file * filp)
schedule();
}
gs_dprintk (GS_DEBUG_BTR, "Got out of the loop. (%d)\n",
port->port.blocked_open);
port->blocked_open);
set_current_state (TASK_RUNNING);
remove_wait_queue(&port->port.open_wait, &wait);
remove_wait_queue(&port->open_wait, &wait);
if (!tty_hung_up_p(filp)) {
port->port.count++;
port->count++;
}
port->port.blocked_open--;
port->blocked_open--;
if (retval)
return retval;
port->port.flags |= ASYNC_NORMAL_ACTIVE;
port->flags |= ASYNC_NORMAL_ACTIVE;
func_exit ();
return 0;
}