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, 32 insertions, 19 deletions

diff --git a/drivers/char/isicom.c b/drivers/char/isicom.c
index 04e4549299ba..b3da4858fd4a 100644
--- a/drivers/char/isicom.c
+++ b/drivers/char/isicom.c
@@ -830,20 +830,28 @@ static int isicom_setup_port(struct tty_struct *tty)
         return 0;
 }
 
+static int isicom_carrier_raised(struct tty_port *port)
+{
+        struct isi_port *ip = container_of(port, struct isi_port, port);
+        return (ip->status & ISI_DCD)?1 : 0;
+}
+
 static int block_til_ready(struct tty_struct *tty, struct file *filp,
-        struct isi_port *port)
+        struct isi_port *ip)
 {
-        struct isi_board *card = port->card;
+        struct isi_board *card = ip->card;
+        struct tty_port *port = &ip->port;
         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->port.flags & ASYNC_CLOSING) {
+        if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
                 pr_dbg("block_til_ready: close in progress.\n");
-                interruptible_sleep_on(&port->port.close_wait);
-                if (port->port.flags & ASYNC_HUP_NOTIFY)
+                interruptible_sleep_on(&port->close_wait);
+                if (port->flags & ASYNC_HUP_NOTIFY)
                         return -EAGAIN;
                 else
                         return -ERESTARTSYS;
@@ -854,7 +862,7 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
         if ((filp->f_flags & O_NONBLOCK) ||
                         (tty->flags & (1 << TTY_IO_ERROR))) {
                 pr_dbg("block_til_ready: non-block mode.\n");
-                port->port.flags |= ASYNC_NORMAL_ACTIVE;
+                port->flags |= ASYNC_NORMAL_ACTIVE;
                 return 0;
         }
 
@@ -864,29 +872,29 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
         /* block waiting for DCD to be asserted, and while
                                                 callout dev is busy */
         retval = 0;
-        add_wait_queue(&port->port.open_wait, &wait);
+        add_wait_queue(&port->open_wait, &wait);
 
         spin_lock_irqsave(&card->card_lock, flags);
         if (!tty_hung_up_p(filp))
-                port->port.count--;
-        port->port.blocked_open++;
+                port->count--;
+        port->blocked_open++;
         spin_unlock_irqrestore(&card->card_lock, flags);
 
         while (1) {
-                raise_dtr_rts(port);
+                raise_dtr_rts(ip);
 
                 set_current_state(TASK_INTERRUPTIBLE);
-                if (tty_hung_up_p(filp) || !(port->port.flags & ASYNC_INITIALIZED)) {
-                        if (port->port.flags & ASYNC_HUP_NOTIFY)
+                if (tty_hung_up_p(filp) || !(port->flags & ASYNC_INITIALIZED)) {
+                        if (port->flags & ASYNC_HUP_NOTIFY)
                                 retval = -EAGAIN;
                         else
                                 retval = -ERESTARTSYS;
                         break;
                 }
-                if (!(port->port.flags & ASYNC_CLOSING) &&
-                                (do_clocal || (port->status & ISI_DCD))) {
+                cd = tty_port_carrier_raised(port);
+                if (!(port->flags & ASYNC_CLOSING) &&
+                                (do_clocal || cd))
                         break;
-                }
                 if (signal_pending(current)) {
                         retval = -ERESTARTSYS;
                         break;
@@ -894,15 +902,15 @@ 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);
         spin_lock_irqsave(&card->card_lock, flags);
         if (!tty_hung_up_p(filp))
-                port->port.count++;
-        port->port.blocked_open--;
+                port->count++;
+        port->blocked_open--;
         spin_unlock_irqrestore(&card->card_lock, flags);
         if (retval)
                 return retval;
-        port->port.flags |= ASYNC_NORMAL_ACTIVE;
+        port->flags |= ASYNC_NORMAL_ACTIVE;
         return 0;
 }
 
@@ -1452,6 +1460,10 @@ static const struct tty_operations isicom_ops = {
         .break_ctl              = isicom_send_break,
 };
 
+static const struct tty_port_operations isicom_port_ops = {
+        .carrier_raised         = isicom_carrier_raised,
+};
+
 static int __devinit reset_card(struct pci_dev *pdev,
         const unsigned int card, unsigned int *signature)
 {
@@ -1794,6 +1806,7 @@ static int __init isicom_init(void)
                 spin_lock_init(&isi_card[idx].card_lock);
                 for (channel = 0; channel < 16; channel++, port++) {
                         tty_port_init(&port->port);
+                        port->port.ops = &isicom_port_ops;
                         port->magic = ISICOM_MAGIC;
                         port->card = &isi_card[idx];
                         port->channel = channel;