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 void usb_debug_break_ctl(struct tty_struct *tty, int break_state)
51 {
52 	struct usb_serial_port *port = tty->driver_data;
53 	if (!break_state)
54 		return;
55 	usb_serial_generic_write(tty, port, USB_DEBUG_BRK, USB_DEBUG_BRK_SIZE);
56 }
57 
usb_debug_process_read_urb(struct urb * urb)58 static void usb_debug_process_read_urb(struct urb *urb)
59 {
60 	struct usb_serial_port *port = urb->context;
61 
62 	if (urb->actual_length == USB_DEBUG_BRK_SIZE &&
63 		memcmp(urb->transfer_buffer, USB_DEBUG_BRK,
64 						USB_DEBUG_BRK_SIZE) == 0) {
65 		usb_serial_handle_break(port);
66 		return;
67 	}
68 
69 	usb_serial_generic_process_read_urb(urb);
70 }
71 
72 static struct usb_serial_driver debug_device = {
73 	.driver = {
74 		.owner =	THIS_MODULE,
75 		.name =		"debug",
76 	},
77 	.id_table =		id_table,
78 	.num_ports =		1,
79 	.bulk_out_size =	USB_DEBUG_MAX_PACKET_SIZE,
80 	.break_ctl =		usb_debug_break_ctl,
81 	.process_read_urb =	usb_debug_process_read_urb,
82 };
83 
84 static struct usb_serial_driver dbc_device = {
85 	.driver = {
86 		.owner =	THIS_MODULE,
87 		.name =		"xhci_dbc",
88 	},
89 	.id_table =		dbc_id_table,
90 	.num_ports =		1,
91 	.break_ctl =		usb_debug_break_ctl,
92 	.process_read_urb =	usb_debug_process_read_urb,
93 };
94 
95 static struct usb_serial_driver * const serial_drivers[] = {
96 	&debug_device, &dbc_device, NULL
97 };
98 
99 module_usb_serial_driver(serial_drivers, id_table_combined);
100 MODULE_LICENSE("GPL v2");
101