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/kernel.h>
  12 #include <linux/init.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 URB_DEBUG_MAX_IN_FLIGHT_URBS    4000
  19 #define USB_DEBUG_MAX_PACKET_SIZE       8
  20 #define USB_DEBUG_BRK_SIZE              8
  21 static char USB_DEBUG_BRK[USB_DEBUG_BRK_SIZE] = {
  22         0x00,
  23         0xff,
  24         0x01,
  25         0xfe,
  26         0x00,
  27         0xfe,
  28         0x01,
  29         0xff,
  30 };
  31
  32 static const struct usb_device_id id_table[] = {
  33         { USB_DEVICE(0x0525, 0x127a) },
  34         { },
  35 };
  36 MODULE_DEVICE_TABLE(usb, id_table);
  37
  38 static struct usb_driver debug_driver = {
  39         .name =         "debug",
  40         .probe =        usb_serial_probe,
  41         .disconnect =   usb_serial_disconnect,
  42         .id_table =     id_table,
  43         .no_dynamic_id =        1,
  44 };
  45
  46 static int usb_debug_open(struct tty_struct *tty, struct usb_serial_port *port)
  47 {
  48         port->bulk_out_size = USB_DEBUG_MAX_PACKET_SIZE;
  49         return usb_serial_generic_open(tty, port);
  50 }
  51
  52 /* This HW really does not support a serial break, so one will be
  53  * emulated when ever the break state is set to true.
  54  */
  55 static void usb_debug_break_ctl(struct tty_struct *tty, int break_state)
  56 {
  57         struct usb_serial_port *port = tty->driver_data;
  58         if (!break_state)
  59                 return;
  60         usb_serial_generic_write(tty, port, USB_DEBUG_BRK, USB_DEBUG_BRK_SIZE);
  61 }
  62
  63 static void usb_debug_read_bulk_callback(struct urb *urb)
  64 {
  65         struct usb_serial_port *port = urb->context;
  66
  67         if (urb->actual_length == USB_DEBUG_BRK_SIZE &&
  68             memcmp(urb->transfer_buffer, USB_DEBUG_BRK,
  69                    USB_DEBUG_BRK_SIZE) == 0) {
  70                 usb_serial_handle_break(port);
  71                 usb_serial_generic_resubmit_read_urb(port, GFP_ATOMIC);
  72                 return;
  73         }
  74
  75         usb_serial_generic_read_bulk_callback(urb);
  76 }
  77
  78 static struct usb_serial_driver debug_device = {
  79         .driver = {
  80                 .owner =        THIS_MODULE,
  81                 .name =         "debug",
  82         },
  83         .id_table =             id_table,
  84         .num_ports =            1,
  85         .open =                 usb_debug_open,
  86         .max_in_flight_urbs =   URB_DEBUG_MAX_IN_FLIGHT_URBS,
  87         .break_ctl =            usb_debug_break_ctl,
  88         .read_bulk_callback =   usb_debug_read_bulk_callback,
  89 };
  90
  91 static int __init debug_init(void)
  92 {
  93         int retval;
  94
  95         retval = usb_serial_register(&debug_device);
  96         if (retval)
  97                 return retval;
  98         retval = usb_register(&debug_driver);
  99         if (retval)
 100                 usb_serial_deregister(&debug_device);
 101         return retval;
 102 }
 103
 104 static void __exit debug_exit(void)
 105 {
 106         usb_deregister(&debug_driver);
 107         usb_serial_deregister(&debug_device);
 108 }
 109
 110 module_init(debug_init);
 111 module_exit(debug_exit);
 112 MODULE_LICENSE("GPL");