tty/hvc_console: Add DTR/RTS callback to handle HUPCL control

Introduce a new callback to explicitly handle the HUPCL termios control flag.
This prepares for a follow-up commit for the hvc_iucv device driver to
improve handling when to drop an established network connection.

The callback naming is based on the recently added tty_port interface to
facilitate a potential refactoring of the hvc_console to use tty_port
functions.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 13 insertions, 1 deletions

diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c
index eb255e807c06..9eba119bcdd3 100644
--- a/drivers/tty/hvc/hvc_console.c
+++ b/drivers/tty/hvc/hvc_console.c
@@ -361,7 +361,12 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
                 tty->driver_data = NULL;
                 tty_port_put(&hp->port);
                 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
-        }
+        } else
+                /* We are ready... raise DTR/RTS */
+                if (C_BAUD(tty))
+                        if (hp->ops->dtr_rts)
+                                hp->ops->dtr_rts(hp, 1);
+
         /* Force wakeup of the polling thread */
         hvc_kick();
 
@@ -393,6 +398,10 @@ static void hvc_close(struct tty_struct *tty, struct file * filp)
                 /* We are done with the tty pointer now. */
                 tty_port_tty_set(&hp->port, NULL);
 
+                if (C_HUPCL(tty))
+                        if (hp->ops->dtr_rts)
+                                hp->ops->dtr_rts(hp, 0);
+
                 if (hp->ops->notifier_del)
                         hp->ops->notifier_del(hp, hp->data);
 
diff --git a/drivers/tty/hvc/hvc_console.h b/drivers/tty/hvc/hvc_console.h
index 674d23cb919a..913101980827 100644
--- a/drivers/tty/hvc/hvc_console.h
+++ b/drivers/tty/hvc/hvc_console.h
@@ -75,6 +75,9 @@ struct hv_ops {
         /* tiocmget/set implementation */
         int (*tiocmget)(struct hvc_struct *hp);
         int (*tiocmset)(struct hvc_struct *hp, unsigned int set, unsigned int clear);
+
+        /* Callbacks to handle tty ports */
+        void (*dtr_rts)(struct hvc_struct *hp, int raise);
 };
 
 /* Register a vterm and a slot index for use as a console (console_init) */