kernel/drivers/usb/serial/usb_debug.c

   1 /*
   2  * USB Debug cable driver
   3  *
   4  * Copyright (C) 2006 Greg Kroah-Hartman <greg@kroah.com>
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License version
   8  *      2 as published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/gfp.h>
  12 #include <linux/kernel.h>
  13 #include <linux/tty.h>
  14 #include <linux/module.h>
  15 #include <linux/usb.h>
  16 #include <linux/usb/serial.h>
  17
  18 #define USB_DEBUG_MAX_PACKET_SIZE       8
  19 #define USB_DEBUG_BRK_SIZE              8
  20 static char USB_DEBUG_BRK[USB_DEBUG_BRK_SIZE] = {
  21         0x00,
  22         0xff,
  23         0x01,
  24         0xfe,
  25         0x00,
  26         0xfe,
  27         0x01,
  28         0xff,
  29 };
  30
  31 static const struct usb_device_id id_table[] = {
  32         { USB_DEVICE(0x0525, 0x127a) },
  33         { },
  34 };
  35 MODULE_DEVICE_TABLE(usb, id_table);
  36
  37 /* This HW really does not support a serial break, so one will be
  38  * emulated when ever the break state is set to true.
  39  */
  40 static void usb_debug_break_ctl(struct tty_struct *tty, int break_state)
  41 {
  42         struct usb_serial_port *port = tty->driver_data;
  43         if (!break_state)
  44                 return;
  45         usb_serial_generic_write(tty, port, USB_DEBUG_BRK, USB_DEBUG_BRK_SIZE);
  46 }
  47
  48 static void usb_debug_process_read_urb(struct urb *urb)
  49 {
  50         struct usb_serial_port *port = urb->context;
  51
  52         if (urb->actual_length == USB_DEBUG_BRK_SIZE &&
  53                 memcmp(urb->transfer_buffer, USB_DEBUG_BRK,
  54                                                 USB_DEBUG_BRK_SIZE) == 0) {
  55                 usb_serial_handle_break(port);
  56                 return;
  57         }
  58
  59         usb_serial_generic_process_read_urb(urb);
  60 }
  61
  62 static struct usb_serial_driver debug_device = {
  63         .driver = {
  64                 .owner =        THIS_MODULE,
  65                 .name =         "debug",
  66         },
  67         .id_table =             id_table,
  68         .num_ports =            1,
  69         .bulk_out_size =        USB_DEBUG_MAX_PACKET_SIZE,
  70         .break_ctl =            usb_debug_break_ctl,
  71         .process_read_urb =     usb_debug_process_read_urb,
  72 };
  73
  74 static struct usb_serial_driver * const serial_drivers[] = {
  75         &debug_device, NULL
  76 };
  77
  78 module_usb_serial_driver(serial_drivers, id_table);
  79 MODULE_LICENSE("GPL");