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/init.h>
  14 #include <linux/tty.h>
  15 #include <linux/module.h>
  16 #include <linux/usb.h>
  17 #include <linux/usb/serial.h>
  18
  19 #define URB_DEBUG_MAX_IN_FLIGHT_URBS    4000
  20 #define USB_DEBUG_MAX_PACKET_SIZE       8
  21 #define USB_DEBUG_BRK_SIZE              8
  22 static char USB_DEBUG_BRK[USB_DEBUG_BRK_SIZE] = {
  23         0x00,
  24         0xff,
  25         0x01,
  26         0xfe,
  27         0x00,
  28         0xfe,
  29         0x01,
  30         0xff,
  31 };
  32
  33 static const struct usb_device_id id_table[] = {
  34         { USB_DEVICE(0x0525, 0x127a) },
  35         { },
  36 };
  37 MODULE_DEVICE_TABLE(usb, id_table);
  38
  39 static struct usb_driver debug_driver = {
  40         .name =         "debug",
  41         .probe =        usb_serial_probe,
  42         .disconnect =   usb_serial_disconnect,
  43         .id_table =     id_table,
  44         .no_dynamic_id =        1,
  45 };
  46
  47 static int usb_debug_open(struct tty_struct *tty, struct usb_serial_port *port)
  48 {
  49         port->bulk_out_size = USB_DEBUG_MAX_PACKET_SIZE;
  50         return usb_serial_generic_open(tty, port);
  51 }
  52
  53 /* This HW really does not support a serial break, so one will be
  54  * emulated when ever the break state is set to true.
  55  */
  56 static void usb_debug_break_ctl(struct tty_struct *tty, int break_state)
  57 {
  58         struct usb_serial_port *port = tty->driver_data;
  59         if (!break_state)
  60                 return;
  61         usb_serial_generic_write(tty, port, USB_DEBUG_BRK, USB_DEBUG_BRK_SIZE);
  62 }
  63
  64 static void usb_debug_read_bulk_callback(struct urb *urb)
  65 {
  66         struct usb_serial_port *port = urb->context;
  67
  68         if (urb->actual_length == USB_DEBUG_BRK_SIZE &&
  69             memcmp(urb->transfer_buffer, USB_DEBUG_BRK,
  70                    USB_DEBUG_BRK_SIZE) == 0) {
  71                 usb_serial_handle_break(port);
  72                 usb_serial_generic_resubmit_read_urb(port, GFP_ATOMIC);
  73                 return;
  74         }
  75
  76         usb_serial_generic_read_bulk_callback(urb);
  77 }
  78
  79 static struct usb_serial_driver debug_device = {
  80         .driver = {
  81                 .owner =        THIS_MODULE,
  82                 .name =         "debug",
  83         },
  84         .id_table =             id_table,
  85         .num_ports =            1,
  86         .open =                 usb_debug_open,
  87         .max_in_flight_urbs =   URB_DEBUG_MAX_IN_FLIGHT_URBS,
  88         .break_ctl =            usb_debug_break_ctl,
  89         .read_bulk_callback =   usb_debug_read_bulk_callback,
  90 };
  91
  92 static int __init debug_init(void)
  93 {
  94         int retval;
  95
  96         retval = usb_serial_register(&debug_device);
  97         if (retval)
  98                 return retval;
  99         retval = usb_register(&debug_driver);
 100         if (retval)
 101                 usb_serial_deregister(&debug_device);
 102         return retval;
 103 }
 104
 105 static void __exit debug_exit(void)
 106 {
 107         usb_deregister(&debug_driver);
 108         usb_serial_deregister(&debug_device);
 109 }
 110
 111 module_init(debug_init);
 112 module_exit(debug_exit);
 113 MODULE_LICENSE("GPL");