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/init.h>
15 #include <linux/tty.h>
16 #include <linux/module.h>
17 #include <linux/usb.h>
18 #include <linux/usb/serial.h>
19 #include <linux/uaccess.h>
20 
21 #define GSI_VENDOR_OPENCLOSE 0xB0
22 
23 static const struct usb_device_id id_table[] = {
24 	{ USB_DEVICE_AND_INTERFACE_INFO(0x1D50, 0x6062, 0xFF, 0xFF, 0xFF) },
25 	{ },
26 };
27 MODULE_DEVICE_TABLE(usb, id_table);
28 
29 /*
30  * Etherbone must be told that a new stream has begun before data arrives.
31  * This is necessary to restart the negotiation of Wishbone bus parameters.
32  * Similarly, when the stream ends, Etherbone must be told so that the cycle
33  * line can be driven low in the case that userspace failed to do so.
34  */
35 static int usb_gsi_openclose(struct usb_serial_port *port, int value)
36 {
37 	struct usb_device *dev = port->serial->dev;
38 
39 	return usb_control_msg(
40 		dev,
41 		usb_sndctrlpipe(dev, 0), /* Send to EP0OUT */
42 		GSI_VENDOR_OPENCLOSE,
43 		USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
44 		value, /* wValue = device is open(1) or closed(0) */
45 		port->serial->interface->cur_altsetting->desc.bInterfaceNumber,
46 		NULL, 0,  /* There is no data stage */
47 		5000); /* Timeout till operation fails */
48 }
49 
50 static int wishbone_serial_open(struct tty_struct *tty,
51 				struct usb_serial_port *port)
52 {
53 	int retval;
54 
55 	retval = usb_gsi_openclose(port, 1);
56 	if (retval) {
57 		dev_err(&port->serial->dev->dev,
58 		       "Could not mark device as open (%d)\n",
59 		       retval);
60 		return retval;
61 	}
62 
63 	retval = usb_serial_generic_open(tty, port);
64 	if (retval)
65 		usb_gsi_openclose(port, 0);
66 
67 	return retval;
68 }
69 
70 static void wishbone_serial_close(struct usb_serial_port *port)
71 {
72 	usb_serial_generic_close(port);
73 	usb_gsi_openclose(port, 0);
74 }
75 
76 static struct usb_serial_driver wishbone_serial_device = {
77 	.driver = {
78 		.owner =	THIS_MODULE,
79 		.name =		"wishbone_serial",
80 	},
81 	.id_table =		id_table,
82 	.num_ports =		1,
83 	.open =			&wishbone_serial_open,
84 	.close =		&wishbone_serial_close,
85 };
86 
87 static struct usb_serial_driver * const serial_drivers[] = {
88 	&wishbone_serial_device, NULL
89 };
90 
91 module_usb_serial_driver(serial_drivers, id_table);
92 
93 MODULE_AUTHOR("Wesley W. Terpstra <w.terpstra@gsi.de>");
94 MODULE_DESCRIPTION("USB Wishbone-Serial adapter");
95 MODULE_LICENSE("GPL");
96