cdc-acm: add TIOCGICOUNT

Simple straightforward implementation. Just returning the statistics
gathered for TIOCMIWAIT

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 7c0051710a047272d534e522b88d07828f6dc595..92e28ecda83459addd4ef7c01167595c9088099b 100644 (file)
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -853,6 +853,27 @@ static int wait_serial_change(struct acm *acm, unsigned long arg)
        return rv;
 }
 
+static int get_serial_usage(struct acm *acm,
+                           struct serial_icounter_struct __user *count)
+{
+       struct serial_icounter_struct icount;
+       int rv = 0;
+
+       memset(&icount, 0, sizeof(icount));
+       icount.dsr = acm->iocount.dsr;
+       icount.rng = acm->iocount.rng;
+       icount.dcd = acm->iocount.dcd;
+       icount.frame = acm->iocount.frame;
+       icount.overrun = acm->iocount.overrun;
+       icount.parity = acm->iocount.parity;
+       icount.brk = acm->iocount.brk;
+
+       if (copy_to_user(count, &icount, sizeof(icount)) > 0)
+               rv = -EFAULT;
+
+       return rv;
+}
+
 static int acm_tty_ioctl(struct tty_struct *tty,
                                        unsigned int cmd, unsigned long arg)
 {
@@ -869,6 +890,9 @@ static int acm_tty_ioctl(struct tty_struct *tty,
        case TIOCMIWAIT:
                rv = wait_serial_change(acm, arg);
                break;
+       case TIOCGICOUNT:
+               rv = get_serial_usage(acm, (struct serial_icounter_struct __user *) arg);
+               break;
        }
 
        return rv;