1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * USB Wishbone-Serial adapter driver
4 *
5 * Copyright (C) 2013 Wesley W. Terpstra <w.terpstra@gsi.de>
6 * Copyright (C) 2013 GSI Helmholtz Centre for Heavy Ion Research GmbH
7 */
8
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#include <linux/uaccess.h>
15
16#define GSI_VENDOR_OPENCLOSE 0xB0
17
18static const struct usb_device_id id_table[] = {
19	{ USB_DEVICE_AND_INTERFACE_INFO(0x1D50, 0x6062, 0xFF, 0xFF, 0xFF) },
20	{ },
21};
22MODULE_DEVICE_TABLE(usb, id_table);
23
24/*
25 * Etherbone must be told that a new stream has begun before data arrives.
26 * This is necessary to restart the negotiation of Wishbone bus parameters.
27 * Similarly, when the stream ends, Etherbone must be told so that the cycle
28 * line can be driven low in the case that userspace failed to do so.
29 */
30static int usb_gsi_openclose(struct usb_serial_port *port, int value)
31{
32	struct usb_device *dev = port->serial->dev;
33
34	return usb_control_msg(
35		dev,
36		usb_sndctrlpipe(dev, 0), /* Send to EP0OUT */
37		GSI_VENDOR_OPENCLOSE,
38		USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
39		value, /* wValue = device is open(1) or closed(0) */
40		port->serial->interface->cur_altsetting->desc.bInterfaceNumber,
41		NULL, 0,  /* There is no data stage */
42		5000); /* Timeout till operation fails */
43}
44
45static int wishbone_serial_open(struct tty_struct *tty,
46				struct usb_serial_port *port)
47{
48	int retval;
49
50	retval = usb_gsi_openclose(port, 1);
51	if (retval) {
52		dev_err(&port->serial->dev->dev,
53		       "Could not mark device as open (%d)\n",
54		       retval);
55		return retval;
56	}
57
58	retval = usb_serial_generic_open(tty, port);
59	if (retval)
60		usb_gsi_openclose(port, 0);
61
62	return retval;
63}
64
65static void wishbone_serial_close(struct usb_serial_port *port)
66{
67	usb_serial_generic_close(port);
68	usb_gsi_openclose(port, 0);
69}
70
71static struct usb_serial_driver wishbone_serial_device = {
72	.driver = {
73		.owner =	THIS_MODULE,
74		.name =		"wishbone_serial",
75	},
76	.id_table =		id_table,
77	.num_ports =		1,
78	.open =			&wishbone_serial_open,
79	.close =		&wishbone_serial_close,
80};
81
82static struct usb_serial_driver * const serial_drivers[] = {
83	&wishbone_serial_device, NULL
84};
85
86module_usb_serial_driver(serial_drivers, id_table);
87
88MODULE_AUTHOR("Wesley W. Terpstra <w.terpstra@gsi.de>");
89MODULE_DESCRIPTION("USB Wishbone-Serial adapter");
90MODULE_LICENSE("GPL");
91