tty_port: Add a port level carrier detect operation
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>
diff --git a/drivers/char/synclink.c b/drivers/char/synclink.c
index 500f517..fb2e6b5 100644
--- a/drivers/char/synclink.c
+++ b/drivers/char/synclink.c
@@ -3281,6 +3281,23 @@
} /* end of mgsl_hangup() */
+/*
+ * carrier_raised()
+ *
+ * Return true if carrier is raised
+ */
+
+static int carrier_raised(struct tty_port *port)
+{
+ unsigned long flags;
+ struct mgsl_struct *info = container_of(port, struct mgsl_struct, port);
+
+ spin_lock_irqsave(&info->irq_spinlock, flags);
+ usc_get_serial_signals(info);
+ spin_unlock_irqrestore(&info->irq_spinlock, flags);
+ return (info->serial_signals & SerialSignal_DCD) ? 1 : 0;
+}
+
/* block_til_ready()
*
* Block the current process until the specified port
@@ -3302,6 +3319,8 @@
bool do_clocal = false;
bool extra_count = false;
unsigned long flags;
+ int dcd;
+ struct tty_port *port = &info->port;
if (debug_level >= DEBUG_LEVEL_INFO)
printk("%s(%d):block_til_ready on %s\n",
@@ -3309,7 +3328,7 @@
if (filp->f_flags & O_NONBLOCK || tty->flags & (1 << TTY_IO_ERROR)){
/* nonblock mode is set or port is not enabled */
- info->port.flags |= ASYNC_NORMAL_ACTIVE;
+ port->flags |= ASYNC_NORMAL_ACTIVE;
return 0;
}
@@ -3318,25 +3337,25 @@
/* Wait for carrier detect and the line to become
* free (i.e., not in use by the callout). While we are in
- * this loop, info->port.count is dropped by one, so that
+ * this loop, port->count is dropped by one, so that
* mgsl_close() knows when to free things. We restore it upon
* exit, either normal or abnormal.
*/
retval = 0;
- add_wait_queue(&info->port.open_wait, &wait);
+ add_wait_queue(&port->open_wait, &wait);
if (debug_level >= DEBUG_LEVEL_INFO)
printk("%s(%d):block_til_ready before block on %s count=%d\n",
- __FILE__,__LINE__, tty->driver->name, info->port.count );
+ __FILE__,__LINE__, tty->driver->name, port->count );
spin_lock_irqsave(&info->irq_spinlock, flags);
if (!tty_hung_up_p(filp)) {
extra_count = true;
- info->port.count--;
+ port->count--;
}
spin_unlock_irqrestore(&info->irq_spinlock, flags);
- info->port.blocked_open++;
+ port->blocked_open++;
while (1) {
if (tty->termios->c_cflag & CBAUD) {
@@ -3348,20 +3367,16 @@
set_current_state(TASK_INTERRUPTIBLE);
- if (tty_hung_up_p(filp) || !(info->port.flags & ASYNC_INITIALIZED)){
- retval = (info->port.flags & ASYNC_HUP_NOTIFY) ?
+ if (tty_hung_up_p(filp) || !(port->flags & ASYNC_INITIALIZED)){
+ retval = (port->flags & ASYNC_HUP_NOTIFY) ?
-EAGAIN : -ERESTARTSYS;
break;
}
- spin_lock_irqsave(&info->irq_spinlock,flags);
- usc_get_serial_signals(info);
- spin_unlock_irqrestore(&info->irq_spinlock,flags);
+ dcd = tty_port_carrier_raised(&info->port);
- if (!(info->port.flags & ASYNC_CLOSING) &&
- (do_clocal || (info->serial_signals & SerialSignal_DCD)) ) {
+ if (!(port->flags & ASYNC_CLOSING) && (do_clocal || dcd))
break;
- }
if (signal_pending(current)) {
retval = -ERESTARTSYS;
@@ -3370,24 +3385,24 @@
if (debug_level >= DEBUG_LEVEL_INFO)
printk("%s(%d):block_til_ready blocking on %s count=%d\n",
- __FILE__,__LINE__, tty->driver->name, info->port.count );
+ __FILE__,__LINE__, tty->driver->name, port->count );
schedule();
}
set_current_state(TASK_RUNNING);
- remove_wait_queue(&info->port.open_wait, &wait);
+ remove_wait_queue(&port->open_wait, &wait);
if (extra_count)
- info->port.count++;
- info->port.blocked_open--;
+ port->count++;
+ port->blocked_open--;
if (debug_level >= DEBUG_LEVEL_INFO)
printk("%s(%d):block_til_ready after blocking on %s count=%d\n",
- __FILE__,__LINE__, tty->driver->name, info->port.count );
+ __FILE__,__LINE__, tty->driver->name, port->count );
if (!retval)
- info->port.flags |= ASYNC_NORMAL_ACTIVE;
+ port->flags |= ASYNC_NORMAL_ACTIVE;
return retval;
@@ -4304,6 +4319,11 @@
} /* end of mgsl_add_device() */
+static const struct tty_port_operations mgsl_port_ops = {
+ .carrier_raised = carrier_raised,
+};
+
+
/* mgsl_allocate_device()
*
* Allocate and initialize a device instance structure
@@ -4322,6 +4342,7 @@
printk("Error can't allocate device instance data\n");
} else {
tty_port_init(&info->port);
+ info->port.ops = &mgsl_port_ops;
info->magic = MGSL_MAGIC;
INIT_WORK(&info->task, mgsl_bh_handler);
info->max_frame_size = 4096;