xref: /openbmc/linux/drivers/usb/serial/usb_debug.c (revision d2c43ff1)
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/tty.h>
14 #include <linux/module.h>
15 #include <linux/usb.h>
16 #include <linux/usb/serial.h>
17 
18 #define USB_DEBUG_MAX_PACKET_SIZE	8
19 #define USB_DEBUG_BRK_SIZE		8
20 static const char USB_DEBUG_BRK[USB_DEBUG_BRK_SIZE] = {
21 	0x00,
22 	0xff,
23 	0x01,
24 	0xfe,
25 	0x00,
26 	0xfe,
27 	0x01,
28 	0xff,
29 };
30 
31 static const struct usb_device_id id_table[] = {
32 	{ USB_DEVICE(0x0525, 0x127a) },
33 	{ },
34 };
35 
36 static const struct usb_device_id dbc_id_table[] = {
37 	{ USB_DEVICE(0x1d6b, 0x0004) },
38 	{ },
39 };
40 
41 static const struct usb_device_id id_table_combined[] = {
42 	{ USB_DEVICE(0x0525, 0x127a) },
43 	{ USB_DEVICE(0x1d6b, 0x0004) },
44 	{ },
45 };
46 MODULE_DEVICE_TABLE(usb, id_table_combined);
47 
48 /* This HW really does not support a serial break, so one will be
49  * emulated when ever the break state is set to true.
50  */
51 static void usb_debug_break_ctl(struct tty_struct *tty, int break_state)
52 {
53 	struct usb_serial_port *port = tty->driver_data;
54 	if (!break_state)
55 		return;
56 	usb_serial_generic_write(tty, port, USB_DEBUG_BRK, USB_DEBUG_BRK_SIZE);
57 }
58 
59 static void usb_debug_process_read_urb(struct urb *urb)
60 {
61 	struct usb_serial_port *port = urb->context;
62 
63 	if (urb->actual_length == USB_DEBUG_BRK_SIZE &&
64 		memcmp(urb->transfer_buffer, USB_DEBUG_BRK,
65 						USB_DEBUG_BRK_SIZE) == 0) {
66 		usb_serial_handle_break(port);
67 		return;
68 	}
69 
70 	usb_serial_generic_process_read_urb(urb);
71 }
72 
73 static struct usb_serial_driver debug_device = {
74 	.driver = {
75 		.owner =	THIS_MODULE,
76 		.name =		"debug",
77 	},
78 	.id_table =		id_table,
79 	.num_ports =		1,
80 	.bulk_out_size =	USB_DEBUG_MAX_PACKET_SIZE,
81 	.break_ctl =		usb_debug_break_ctl,
82 	.process_read_urb =	usb_debug_process_read_urb,
83 };
84 
85 static struct usb_serial_driver dbc_device = {
86 	.driver = {
87 		.owner =	THIS_MODULE,
88 		.name =		"xhci_dbc",
89 	},
90 	.id_table =		dbc_id_table,
91 	.num_ports =		1,
92 	.break_ctl =		usb_debug_break_ctl,
93 	.process_read_urb =	usb_debug_process_read_urb,
94 };
95 
96 static struct usb_serial_driver * const serial_drivers[] = {
97 	&debug_device, &dbc_device, NULL
98 };
99 
100 module_usb_serial_driver(serial_drivers, id_table_combined);
101 MODULE_LICENSE("GPL");
102