drivers/usb/serial/usb_debug.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * USB Debug cable driver
   4  *
   5  * Copyright (C) 2006 Greg Kroah-Hartman <[email protected]>
   6  */
   7
   8 #include <linux/gfp.h>
   9 #include <linux/kernel.h>
  10 #include <linux/tty.h>
  11 #include <linux/module.h>
  12 #include <linux/usb.h>
  13 #include <linux/usb/serial.h>
  14
  15 #define USB_DEBUG_MAX_PACKET_SIZE       8
  16 #define USB_DEBUG_BRK_SIZE              8
  17 static const char USB_DEBUG_BRK[USB_DEBUG_BRK_SIZE] = {
  18         0x00,
  19         0xff,
  20         0x01,
  21         0xfe,
  22         0x00,
  23         0xfe,
  24         0x01,
  25         0xff,
  26 };
  27
  28 static const struct usb_device_id id_table[] = {
  29         { USB_DEVICE(0x0525, 0x127a) },
  30         { },
  31 };
  32
  33 static const struct usb_device_id dbc_id_table[] = {
  34         { USB_DEVICE(0x1d6b, 0x0010) },
  35         { USB_DEVICE(0x1d6b, 0x0011) },
  36         { },
  37 };
  38
  39 static const struct usb_device_id id_table_combined[] = {
  40         { USB_DEVICE(0x0525, 0x127a) },
  41         { USB_DEVICE(0x1d6b, 0x0010) },
  42         { USB_DEVICE(0x1d6b, 0x0011) },
  43         { },
  44 };
  45 MODULE_DEVICE_TABLE(usb, id_table_combined);
  46
  47 /* This HW really does not support a serial break, so one will be
  48  * emulated when ever the break state is set to true.
  49  */
  50 static int usb_debug_break_ctl(struct tty_struct *tty, int break_state)
  51 {
  52         struct usb_serial_port *port = tty->driver_data;
  53         int ret;
  54
  55         if (!break_state)
  56                 return 0;
  57
  58         ret = usb_serial_generic_write(tty, port, USB_DEBUG_BRK, USB_DEBUG_BRK_SIZE);
  59         if (ret < 0)
  60                 return ret;
  61
  62         return 0;
  63 }
  64
  65 static void usb_debug_process_read_urb(struct urb *urb)
  66 {
  67         struct usb_serial_port *port = urb->context;
  68
  69         if (urb->actual_length == USB_DEBUG_BRK_SIZE &&
  70                 memcmp(urb->transfer_buffer, USB_DEBUG_BRK,
  71                                                 USB_DEBUG_BRK_SIZE) == 0) {
  72                 usb_serial_handle_break(port);
  73                 return;
  74         }
  75
  76         usb_serial_generic_process_read_urb(urb);
  77 }
  78
  79 static void usb_debug_init_termios(struct tty_struct *tty)
  80 {
  81         tty->termios.c_lflag &= ~(ECHO | ECHONL);
  82 }
  83
  84 static struct usb_serial_driver debug_device = {
  85         .driver = {
  86                 .name =         "debug",
  87         },
  88         .id_table =             id_table,
  89         .num_ports =            1,
  90         .bulk_out_size =        USB_DEBUG_MAX_PACKET_SIZE,
  91         .break_ctl =            usb_debug_break_ctl,
  92         .init_termios =         usb_debug_init_termios,
  93         .process_read_urb =     usb_debug_process_read_urb,
  94 };
  95
  96 static struct usb_serial_driver dbc_device = {
  97         .driver = {
  98                 .name =         "xhci_dbc",
  99         },
 100         .id_table =             dbc_id_table,
 101         .num_ports =            1,
 102         .break_ctl =            usb_debug_break_ctl,
 103         .init_termios =         usb_debug_init_termios,
 104         .process_read_urb =     usb_debug_process_read_urb,
 105 };
 106
 107 static struct usb_serial_driver * const serial_drivers[] = {
 108         &debug_device, &dbc_device, NULL
 109 };
 110
 111 module_usb_serial_driver(serial_drivers, id_table_combined);
 112 MODULE_DESCRIPTION("USB Debug cable driver");
 113 MODULE_LICENSE("GPL v2");