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, 35 insertions, 20 deletions

diff --git a/drivers/char/synclinkmp.c b/drivers/char/synclinkmp.c
index 6bdb44f7bec2..fcf1ec77450d 100644
--- a/drivers/char/synclinkmp.c
+++ b/drivers/char/synclinkmp.c
@@ -558,6 +558,7 @@ static void release_resources(SLMP_INFO *info);
 
 static int  startup(SLMP_INFO *info);
 static int  block_til_ready(struct tty_struct *tty, struct file * filp,SLMP_INFO *info);
+static int carrier_raised(struct tty_port *port);
 static void shutdown(SLMP_INFO *info);
 static void program_hw(SLMP_INFO *info);
 static void change_params(SLMP_INFO *info);
@@ -3318,7 +3319,17 @@ static int tiocmset(struct tty_struct *tty, struct file *file,
         return 0;
 }
 
+static int carrier_raised(struct tty_port *port)
+{
+        SLMP_INFO *info = container_of(port, SLMP_INFO, port);
+        unsigned long flags;
 
+        spin_lock_irqsave(&info->lock,flags);
+        get_signals(info);
+        spin_unlock_irqrestore(&info->lock,flags);
+
+        return (info->serial_signals & SerialSignal_DCD) ? 1 : 0;
+}
 
 /* Block the current process until the specified port is ready to open.
  */
@@ -3330,6 +3341,8 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
         bool            do_clocal = false;
         bool            extra_count = false;
         unsigned long   flags;
+        int             cd;
+        struct tty_port *port = &info->port;
 
         if (debug_level >= DEBUG_LEVEL_INFO)
                 printk("%s(%d):%s block_til_ready()\n",
@@ -3338,7 +3351,7 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
         if (filp->f_flags & O_NONBLOCK || tty->flags & (1 << TTY_IO_ERROR)){
                 /* nonblock mode is set or port is not enabled */
                 /* just verify that callout device is not active */
-                info->port.flags |= ASYNC_NORMAL_ACTIVE;
+                port->flags |= ASYNC_NORMAL_ACTIVE;
                 return 0;
         }
 
@@ -3347,25 +3360,25 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
 
         /* 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
          * 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):%s block_til_ready() before block, count=%d\n",
-                         __FILE__,__LINE__, tty->driver->name, info->port.count );
+                         __FILE__,__LINE__, tty->driver->name, port->count );
 
         spin_lock_irqsave(&info->lock, flags);
         if (!tty_hung_up_p(filp)) {
                 extra_count = true;
-                info->port.count--;
+                port->count--;
         }
         spin_unlock_irqrestore(&info->lock, flags);
-        info->port.blocked_open++;
+        port->blocked_open++;
 
         while (1) {
                 if ((tty->termios->c_cflag & CBAUD)) {
@@ -3377,20 +3390,16 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
 
                 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->lock,flags);
-                get_signals(info);
-                spin_unlock_irqrestore(&info->lock,flags);
+                cd = tty_port_carrier_raised(port);
 
-                if (!(info->port.flags & ASYNC_CLOSING) &&
-                    (do_clocal || (info->serial_signals & SerialSignal_DCD)) ) {
+                if (!(port->flags & ASYNC_CLOSING) && (do_clocal || cd))
                         break;
-                }
 
                 if (signal_pending(current)) {
                         retval = -ERESTARTSYS;
@@ -3399,24 +3408,24 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
 
                 if (debug_level >= DEBUG_LEVEL_INFO)
                         printk("%s(%d):%s block_til_ready() 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):%s block_til_ready() after, 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;
 }
@@ -3782,6 +3791,10 @@ static void add_device(SLMP_INFO *info)
 #endif
 }
 
+static const struct tty_port_operations port_ops = {
+        .carrier_raised = carrier_raised,
+};
+
 /* Allocate and initialize a device instance structure
  *
  * Return Value:        pointer to SLMP_INFO if success, otherwise NULL
@@ -3798,6 +3811,7 @@ static SLMP_INFO *alloc_dev(int adapter_num, int port_num, struct pci_dev *pdev)
                         __FILE__,__LINE__, adapter_num, port_num);
         } else {
                 tty_port_init(&info->port);
+                info->port.ops = &port_ops;
                 info->magic = MGSL_MAGIC;
                 INIT_WORK(&info->task, bh_handler);
                 info->max_frame_size = 4096;
@@ -3940,6 +3954,7 @@ static const struct tty_operations ops = {
         .tiocmset = tiocmset,
 };
 
+
 static void synclinkmp_cleanup(void)
 {
         int rc;