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, 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 */
usb_debug_break_ctl(struct tty_struct * tty,int break_state)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
usb_debug_process_read_urb(struct urb * urb)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
usb_debug_init_termios(struct tty_struct * tty)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");
114