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 <greg@kroah.com>
   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, 0x0011) },
  35         { },
  36 };
  37
  38 static const struct usb_device_id id_table_combined[] = {
  39         { USB_DEVICE(0x0525, 0x127a) },
  40         { USB_DEVICE(0x1d6b, 0x0011) },
  41         { },
  42 };
  43 MODULE_DEVICE_TABLE(usb, id_table_combined);
  44
  45 /* This HW really does not support a serial break, so one will be
  46  * emulated when ever the break state is set to true.
  47  */
  48 static void usb_debug_break_ctl(struct tty_struct *tty, int break_state)
  49 {
  50         struct usb_serial_port *port = tty->driver_data;
  51         if (!break_state)
  52                 return;
  53         usb_serial_generic_write(tty, port, USB_DEBUG_BRK, USB_DEBUG_BRK_SIZE);
  54 }
  55
  56 static void usb_debug_process_read_urb(struct urb *urb)
  57 {
  58         struct usb_serial_port *port = urb->context;
  59
  60         if (urb->actual_length == USB_DEBUG_BRK_SIZE &&
  61                 memcmp(urb->transfer_buffer, USB_DEBUG_BRK,
  62                                                 USB_DEBUG_BRK_SIZE) == 0) {
  63                 usb_serial_handle_break(port);
  64                 return;
  65         }
  66
  67         usb_serial_generic_process_read_urb(urb);
  68 }
  69
  70 static struct usb_serial_driver debug_device = {
  71         .driver = {
  72                 .owner =        THIS_MODULE,
  73                 .name =         "debug",
  74         },
  75         .id_table =             id_table,
  76         .num_ports =            1,
  77         .bulk_out_size =        USB_DEBUG_MAX_PACKET_SIZE,
  78         .break_ctl =            usb_debug_break_ctl,
  79         .process_read_urb =     usb_debug_process_read_urb,
  80 };
  81
  82 static struct usb_serial_driver dbc_device = {
  83         .driver = {
  84                 .owner =        THIS_MODULE,
  85                 .name =         "xhci_dbc",
  86         },
  87         .id_table =             dbc_id_table,
  88         .num_ports =            1,
  89         .break_ctl =            usb_debug_break_ctl,
  90         .process_read_urb =     usb_debug_process_read_urb,
  91 };
  92
  93 static struct usb_serial_driver * const serial_drivers[] = {
  94         &debug_device, &dbc_device, NULL
  95 };
  96
  97 module_usb_serial_driver(serial_drivers, id_table_combined);
  98 MODULE_LICENSE("GPL v2");