1 files changed, 41 insertions, 0 deletions

diff --git a/drivers/usb/serial/usb_debug.c b/drivers/usb/serial/usb_debug.c
index 6c9cbb59552a..614800972dc3 100644
--- a/drivers/usb/serial/usb_debug.c
+++ b/drivers/usb/serial/usb_debug.c
@@ -15,7 +15,19 @@
 #include <linux/usb.h>
 #include <linux/usb/serial.h>
 
+#define URB_DEBUG_MAX_IN_FLIGHT_URBS    4000
 #define USB_DEBUG_MAX_PACKET_SIZE       8
+#define USB_DEBUG_BRK_SIZE              8
+static char USB_DEBUG_BRK[USB_DEBUG_BRK_SIZE] = {
+        0x00,
+        0xff,
+        0x01,
+        0xfe,
+        0x00,
+        0xfe,
+        0x01,
+        0xff,
+};
 
 static struct usb_device_id id_table [] = {
         { USB_DEVICE(0x0525, 0x127a) },
@@ -38,6 +50,32 @@ static int usb_debug_open(struct tty_struct *tty, struct usb_serial_port *port,
         return usb_serial_generic_open(tty, port, filp);
 }
 
+/* This HW really does not support a serial break, so one will be
+ * emulated when ever the break state is set to true.
+ */
+static void usb_debug_break_ctl(struct tty_struct *tty, int break_state)
+{
+        struct usb_serial_port *port = tty->driver_data;
+        if (!break_state)
+                return;
+        usb_serial_generic_write(tty, port, USB_DEBUG_BRK, USB_DEBUG_BRK_SIZE);
+}
+
+static void usb_debug_read_bulk_callback(struct urb *urb)
+{
+        struct usb_serial_port *port = urb->context;
+
+        if (urb->actual_length == USB_DEBUG_BRK_SIZE &&
+            memcmp(urb->transfer_buffer, USB_DEBUG_BRK,
+                   USB_DEBUG_BRK_SIZE) == 0) {
+                usb_serial_handle_break(port);
+                usb_serial_generic_resubmit_read_urb(port, GFP_ATOMIC);
+                return;
+        }
+
+        usb_serial_generic_read_bulk_callback(urb);
+}
+
 static struct usb_serial_driver debug_device = {
         .driver = {
                 .owner =        THIS_MODULE,
@@ -46,6 +84,9 @@ static struct usb_serial_driver debug_device = {
         .id_table =             id_table,
         .num_ports =            1,
         .open =                 usb_debug_open,
+        .max_in_flight_urbs =   URB_DEBUG_MAX_IN_FLIGHT_URBS,
+        .break_ctl =            usb_debug_break_ctl,
+        .read_bulk_callback =   usb_debug_read_bulk_callback,
 };
 
 static int __init debug_init(void)