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>

1 files changed, 40 insertions, 25 deletions

diff --git a/drivers/char/riscom8.c b/drivers/char/riscom8.c
index 2c6c8f33d6b4..6ad1c2aa2a98 100644
--- a/drivers/char/riscom8.c
+++ b/drivers/char/riscom8.c
@@ -857,23 +857,40 @@ static void rc_shutdown_port(struct tty_struct *tty,
                 rc_shutdown_board(bp);
 }
 
+static int carrier_raised(struct tty_port *port)
+{
+        struct riscom_port *p = container_of(port, struct riscom_port, port);
+        struct riscom_board *bp = port_Board(p);
+        unsigned long flags;
+        int CD;
+        
+        spin_lock_irqsave(&riscom_lock, flags);
+        rc_out(bp, CD180_CAR, port_No(p));
+        CD = rc_in(bp, CD180_MSVR) & MSVR_CD;
+        rc_out(bp, CD180_MSVR, MSVR_RTS);
+        bp->DTR &= ~(1u << port_No(p));
+        rc_out(bp, RC_DTR, bp->DTR);
+        spin_unlock_irqrestore(&riscom_lock, flags);
+        return CD;
+}
+
 static int block_til_ready(struct tty_struct *tty, struct file *filp,
-                           struct riscom_port *port)
+                           struct riscom_port *rp)
 {
         DECLARE_WAITQUEUE(wait, current);
-        struct riscom_board *bp = port_Board(port);
         int    retval;
         int    do_clocal = 0;
         int    CD;
         unsigned long flags;
+        struct tty_port *port = &rp->port;
 
         /*
          * 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;
@@ -885,7 +902,7 @@ static int block_til_ready(struct tty_struct *tty, 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;
         }
 
@@ -900,37 +917,29 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
          * exit, either normal or abnormal.
          */
         retval = 0;
-        add_wait_queue(&port->port.open_wait, &wait);
+        add_wait_queue(&port->open_wait, &wait);
 
         spin_lock_irqsave(&riscom_lock, flags);
 
         if (!tty_hung_up_p(filp))
-                port->port.count--;
+                port->count--;
 
         spin_unlock_irqrestore(&riscom_lock, flags);
 
-        port->port.blocked_open++;
+        port->blocked_open++;
         while (1) {
-                spin_lock_irqsave(&riscom_lock, flags);
-
-                rc_out(bp, CD180_CAR, port_No(port));
-                CD = rc_in(bp, CD180_MSVR) & MSVR_CD;
-                rc_out(bp, CD180_MSVR, MSVR_RTS);
-                bp->DTR &= ~(1u << port_No(port));
-                rc_out(bp, RC_DTR, bp->DTR);
-
-                spin_unlock_irqrestore(&riscom_lock, flags);
 
+                CD = tty_port_carrier_raised(port);
                 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;
                 if (signal_pending(current)) {
@@ -940,14 +949,14 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
                 schedule();
         }
         __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->port.blocked_open--;
+                port->count++;
+        port->blocked_open--;
         if (retval)
                 return retval;
 
-        port->port.flags |= ASYNC_NORMAL_ACTIVE;
+        port->flags |= ASYNC_NORMAL_ACTIVE;
         return 0;
 }
 
@@ -1510,6 +1519,11 @@ static const struct tty_operations riscom_ops = {
         .break_ctl = rc_send_break,
 };
 
+static const struct tty_port_operations riscom_port_ops = {
+        .carrier_raised = carrier_raised,
+};
+
+
 static int __init rc_init_drivers(void)
 {
         int error;
@@ -1541,6 +1555,7 @@ static int __init rc_init_drivers(void)
         memset(rc_port, 0, sizeof(rc_port));
         for (i = 0; i < RC_NPORT * RC_NBOARD; i++)  {
                 tty_port_init(&rc_port[i].port);
+                rc_port[i].port.ops = &riscom_port_ops;
                 rc_port[i].magic = RISCOM8_MAGIC;
         }
         return 0;