5 files changed, 61 insertions, 19 deletions

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index e185db36f8ad..c05c5af5aa04 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -96,6 +96,7 @@
 #include <linux/bitops.h>
 #include <linux/delay.h>
 #include <linux/seq_file.h>
+#include <linux/serial.h>
 
 #include <linux/uaccess.h>
 #include <asm/system.h>
@@ -2511,6 +2512,20 @@ static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int
         return tty->ops->tiocmset(tty, file, set, clear);
 }
 
+static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
+{
+        int retval = -EINVAL;
+        struct serial_icounter_struct icount;
+        memset(&icount, 0, sizeof(icount));
+        if (tty->ops->get_icount)
+                retval = tty->ops->get_icount(tty, &icount);
+        if (retval != 0)
+                return retval;
+        if (copy_to_user(arg, &icount, sizeof(icount)))
+                return -EFAULT;
+        return 0;
+}
+
 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
 {
         if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
@@ -2631,6 +2646,12 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
         case TIOCMBIC:
         case TIOCMBIS:
                 return tty_tiocmset(tty, file, cmd, p);
+        case TIOCGICOUNT:
+                retval = tty_tiocgicount(tty, p);
+                /* For the moment allow fall through to the old method */
+                if (retval != -EINVAL)
+                        return retval;
+                break;
         case TCFLSH:
                 switch (arg) {
                 case TCIFLUSH:
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index bc6cddd10294..c4ea14670d44 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1074,10 +1074,10 @@ uart_wait_modem_status(struct uart_state *state, unsigned long arg)
  * NB: both 1->0 and 0->1 transitions are counted except for
  *     RI where only 0->1 is counted.
  */
-static int uart_get_count(struct uart_state *state,
-                          struct serial_icounter_struct __user *icnt)
+static int uart_get_icount(struct tty_struct *tty,
+                          struct serial_icounter_struct *icount)
 {
-        struct serial_icounter_struct icount;
+        struct uart_state *state = tty->driver_data;
         struct uart_icount cnow;
         struct uart_port *uport = state->uart_port;
 
@@ -1085,19 +1085,19 @@ static int uart_get_count(struct uart_state *state,
         memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
         spin_unlock_irq(&uport->lock);
 
-        icount.cts         = cnow.cts;
-        icount.dsr         = cnow.dsr;
-        icount.rng         = cnow.rng;
-        icount.dcd         = cnow.dcd;
-        icount.rx          = cnow.rx;
-        icount.tx          = cnow.tx;
-        icount.frame       = cnow.frame;
-        icount.overrun     = cnow.overrun;
-        icount.parity      = cnow.parity;
-        icount.brk         = cnow.brk;
-        icount.buf_overrun = cnow.buf_overrun;
+        icount->cts         = cnow.cts;
+        icount->dsr         = cnow.dsr;
+        icount->rng         = cnow.rng;
+        icount->dcd         = cnow.dcd;
+        icount->rx          = cnow.rx;
+        icount->tx          = cnow.tx;
+        icount->frame       = cnow.frame;
+        icount->overrun     = cnow.overrun;
+        icount->parity      = cnow.parity;
+        icount->brk         = cnow.brk;
+        icount->buf_overrun = cnow.buf_overrun;
 
-        return copy_to_user(icnt, &icount, sizeof(icount)) ? -EFAULT : 0;
+        return 0;
 }
 
 /*
@@ -1150,10 +1150,6 @@ uart_ioctl(struct tty_struct *tty, struct file *filp, unsigned int cmd,
         case TIOCMIWAIT:
                 ret = uart_wait_modem_status(state, arg);
                 break;
-
-        case TIOCGICOUNT:
-                ret = uart_get_count(state, uarg);
-                break;
         }
 
         if (ret != -ENOIOCTLCMD)
@@ -2295,6 +2291,7 @@ static const struct tty_operations uart_ops = {
 #endif
         .tiocmget       = uart_tiocmget,
         .tiocmset       = uart_tiocmset,
+        .get_icount     = uart_get_icount,
 #ifdef CONFIG_CONSOLE_POLL
         .poll_init      = uart_poll_init,
         .poll_get_char  = uart_poll_get_char,
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 7a2177c79bde..e64da74bdcc5 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -519,6 +519,18 @@ static int serial_tiocmset(struct tty_struct *tty, struct file *file,
         return -EINVAL;
 }
 
+static int serial_get_icount(struct tty_struct *tty,
+                                struct serial_icounter_struct *icount)
+{
+        struct usb_serial_port *port = tty->driver_data;
+
+        dbg("%s - port %d", __func__, port->number);
+
+        if (port->serial->type->get_icount)
+                return port->serial->type->get_icount(tty, icount);
+        return -EINVAL;
+}
+
 /*
  * We would be calling tty_wakeup here, but unfortunately some line
  * disciplines have an annoying habit of calling tty->write from
@@ -1195,6 +1207,7 @@ static const struct tty_operations serial_ops = {
         .chars_in_buffer =      serial_chars_in_buffer,
         .tiocmget =             serial_tiocmget,
         .tiocmset =             serial_tiocmset,
+        .get_icount =           serial_get_icount,
         .cleanup =              serial_cleanup,
         .install =              serial_install,
         .proc_fops =            &serial_proc_fops,
diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index b08677982525..db2d227694da 100644
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -224,6 +224,12 @@
  *      unless the tty also has a valid tty->termiox pointer.
  *
  *      Optional: Called under the termios lock
+ *
+ * int (*get_icount)(struct tty_struct *tty, struct serial_icounter *icount);
+ *
+ *      Called when the device receives a TIOCGICOUNT ioctl. Passed a kernel
+ *      structure to complete. This method is optional and will only be called
+ *      if provided (otherwise EINVAL will be returned).
  */
 
 #include <linux/fs.h>
@@ -232,6 +238,7 @@
 
 struct tty_struct;
 struct tty_driver;
+struct serial_icounter_struct;
 
 struct tty_operations {
         struct tty_struct * (*lookup)(struct tty_driver *driver,
@@ -268,6 +275,8 @@ struct tty_operations {
                         unsigned int set, unsigned int clear);
         int (*resize)(struct tty_struct *tty, struct winsize *ws);
         int (*set_termiox)(struct tty_struct *tty, struct termiox *tnew);
+        int (*get_icount)(struct tty_struct *tty,
+                                struct serial_icounter_struct *icount);
 #ifdef CONFIG_CONSOLE_POLL
         int (*poll_init)(struct tty_driver *driver, int line, char *options);
         int (*poll_get_char)(struct tty_driver *driver, int line);
diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index 55675b1efb28..16d682f4f7c3 100644
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -271,6 +271,8 @@ struct usb_serial_driver {
         int  (*tiocmget)(struct tty_struct *tty, struct file *file);
         int  (*tiocmset)(struct tty_struct *tty, struct file *file,
                          unsigned int set, unsigned int clear);
+        int  (*get_icount)(struct tty_struct *tty,
+                        struct serial_icounter_struct *icount);
         /* Called by the tty layer for port level work. There may or may not
            be an attached tty at this point */
         void (*dtr_rts)(struct usb_serial_port *port, int on);