1/*
2 * USB Wishbone-Serial adapter driver
3 *
4 * Copyright (C) 2013 Wesley W. Terpstra <w.terpstra@gsi.de>
5 * Copyright (C) 2013 GSI Helmholtz Centre for Heavy Ion Research GmbH
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version 2
10 * of the License, or (at your option) any later version.
11 */
12
13#include <linux/kernel.h>
14#include <linux/tty.h>
15#include <linux/module.h>
16#include <linux/usb.h>
17#include <linux/usb/serial.h>
18#include <linux/uaccess.h>
19
20#define GSI_VENDOR_OPENCLOSE 0xB0
21
22static const struct usb_device_id id_table[] = {
23	{ USB_DEVICE_AND_INTERFACE_INFO(0x1D50, 0x6062, 0xFF, 0xFF, 0xFF) },
24	{ },
25};
26MODULE_DEVICE_TABLE(usb, id_table);
27
28/*
29 * Etherbone must be told that a new stream has begun before data arrives.
30 * This is necessary to restart the negotiation of Wishbone bus parameters.
31 * Similarly, when the stream ends, Etherbone must be told so that the cycle
32 * line can be driven low in the case that userspace failed to do so.
33 */
34static int usb_gsi_openclose(struct usb_serial_port *port, int value)
35{
36	struct usb_device *dev = port->serial->dev;
37
38	return usb_control_msg(
39		dev,
40		usb_sndctrlpipe(dev, 0), /* Send to EP0OUT */
41		GSI_VENDOR_OPENCLOSE,
42		USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
43		value, /* wValue = device is open(1) or closed(0) */
44		port->serial->interface->cur_altsetting->desc.bInterfaceNumber,
45		NULL, 0,  /* There is no data stage */
46		5000); /* Timeout till operation fails */
47}
48
49static int wishbone_serial_open(struct tty_struct *tty,
50				struct usb_serial_port *port)
51{
52	int retval;
53
54	retval = usb_gsi_openclose(port, 1);
55	if (retval) {
56		dev_err(&port->serial->dev->dev,
57		       "Could not mark device as open (%d)\n",
58		       retval);
59		return retval;
60	}
61
62	retval = usb_serial_generic_open(tty, port);
63	if (retval)
64		usb_gsi_openclose(port, 0);
65
66	return retval;
67}
68
69static void wishbone_serial_close(struct usb_serial_port *port)
70{
71	usb_serial_generic_close(port);
72	usb_gsi_openclose(port, 0);
73}
74
75static struct usb_serial_driver wishbone_serial_device = {
76	.driver = {
77		.owner =	THIS_MODULE,
78		.name =		"wishbone_serial",
79	},
80	.id_table =		id_table,
81	.num_ports =		1,
82	.open =			&wishbone_serial_open,
83	.close =		&wishbone_serial_close,
84};
85
86static struct usb_serial_driver * const serial_drivers[] = {
87	&wishbone_serial_device, NULL
88};
89
90module_usb_serial_driver(serial_drivers, id_table);
91
92MODULE_AUTHOR("Wesley W. Terpstra <w.terpstra@gsi.de>");
93MODULE_DESCRIPTION("USB Wishbone-Serial adapter");
94MODULE_LICENSE("GPL");
95