1/*
2 * USB ZyXEL omni.net LCD PLUS driver
3 *
4 *	This program is free software; you can redistribute it and/or
5 *	modify it under the terms of the GNU General Public License version
6 *	2 as published by the Free Software Foundation.
7 *
8 * See Documentation/usb/usb-serial.txt for more information on using this
9 * driver
10 *
11 * Please report both successes and troubles to the author at omninet@kroah.com
12 */
13
14#include <linux/kernel.h>
15#include <linux/errno.h>
16#include <linux/slab.h>
17#include <linux/tty.h>
18#include <linux/tty_driver.h>
19#include <linux/tty_flip.h>
20#include <linux/module.h>
21#include <linux/uaccess.h>
22#include <linux/usb.h>
23#include <linux/usb/serial.h>
24
25#define DRIVER_AUTHOR "Alessandro Zummo"
26#define DRIVER_DESC "USB ZyXEL omni.net LCD PLUS Driver"
27
28#define ZYXEL_VENDOR_ID		0x0586
29#define ZYXEL_OMNINET_ID	0x1000
30/* This one seems to be a re-branded ZyXEL device */
31#define BT_IGNITIONPRO_ID	0x2000
32
33/* function prototypes */
34static int  omninet_open(struct tty_struct *tty, struct usb_serial_port *port);
35static void omninet_process_read_urb(struct urb *urb);
36static void omninet_write_bulk_callback(struct urb *urb);
37static int  omninet_write(struct tty_struct *tty, struct usb_serial_port *port,
38				const unsigned char *buf, int count);
39static int  omninet_write_room(struct tty_struct *tty);
40static void omninet_disconnect(struct usb_serial *serial);
41static int omninet_port_probe(struct usb_serial_port *port);
42static int omninet_port_remove(struct usb_serial_port *port);
43
44static const struct usb_device_id id_table[] = {
45	{ USB_DEVICE(ZYXEL_VENDOR_ID, ZYXEL_OMNINET_ID) },
46	{ USB_DEVICE(ZYXEL_VENDOR_ID, BT_IGNITIONPRO_ID) },
47	{ }						/* Terminating entry */
48};
49MODULE_DEVICE_TABLE(usb, id_table);
50
51static struct usb_serial_driver zyxel_omninet_device = {
52	.driver = {
53		.owner =	THIS_MODULE,
54		.name =		"omninet",
55	},
56	.description =		"ZyXEL - omni.net lcd plus usb",
57	.id_table =		id_table,
58	.num_ports =		1,
59	.port_probe =		omninet_port_probe,
60	.port_remove =		omninet_port_remove,
61	.open =			omninet_open,
62	.write =		omninet_write,
63	.write_room =		omninet_write_room,
64	.write_bulk_callback =	omninet_write_bulk_callback,
65	.process_read_urb =	omninet_process_read_urb,
66	.disconnect =		omninet_disconnect,
67};
68
69static struct usb_serial_driver * const serial_drivers[] = {
70	&zyxel_omninet_device, NULL
71};
72
73
74/*
75 * The protocol.
76 *
77 * The omni.net always exchange 64 bytes of data with the host. The first
78 * four bytes are the control header.
79 *
80 * oh_seq is a sequence number. Don't know if/how it's used.
81 * oh_len is the length of the data bytes in the packet.
82 * oh_xxx Bit-mapped, related to handshaking and status info.
83 *	I normally set it to 0x03 in transmitted frames.
84 *	7: Active when the TA is in a CONNECTed state.
85 *	6: unknown
86 *	5: handshaking, unknown
87 *	4: handshaking, unknown
88 *	3: unknown, usually 0
89 *	2: unknown, usually 0
90 *	1: handshaking, unknown, usually set to 1 in transmitted frames
91 *	0: handshaking, unknown, usually set to 1 in transmitted frames
92 * oh_pad Probably a pad byte.
93 *
94 * After the header you will find data bytes if oh_len was greater than zero.
95 */
96struct omninet_header {
97	__u8	oh_seq;
98	__u8	oh_len;
99	__u8	oh_xxx;
100	__u8	oh_pad;
101};
102
103struct omninet_data {
104	__u8	od_outseq;	/* Sequence number for bulk_out URBs */
105};
106
107static int omninet_port_probe(struct usb_serial_port *port)
108{
109	struct omninet_data *od;
110
111	od = kzalloc(sizeof(*od), GFP_KERNEL);
112	if (!od)
113		return -ENOMEM;
114
115	usb_set_serial_port_data(port, od);
116
117	return 0;
118}
119
120static int omninet_port_remove(struct usb_serial_port *port)
121{
122	struct omninet_data *od;
123
124	od = usb_get_serial_port_data(port);
125	kfree(od);
126
127	return 0;
128}
129
130static int omninet_open(struct tty_struct *tty, struct usb_serial_port *port)
131{
132	struct usb_serial	*serial = port->serial;
133	struct usb_serial_port	*wport;
134
135	wport = serial->port[1];
136	tty_port_tty_set(&wport->port, tty);
137
138	return usb_serial_generic_open(tty, port);
139}
140
141#define OMNINET_HEADERLEN	4
142#define OMNINET_BULKOUTSIZE	64
143#define OMNINET_PAYLOADSIZE	(OMNINET_BULKOUTSIZE - OMNINET_HEADERLEN)
144
145static void omninet_process_read_urb(struct urb *urb)
146{
147	struct usb_serial_port *port = urb->context;
148	const struct omninet_header *hdr = urb->transfer_buffer;
149	const unsigned char *data;
150	size_t data_len;
151
152	if (urb->actual_length <= OMNINET_HEADERLEN || !hdr->oh_len)
153		return;
154
155	data = (char *)urb->transfer_buffer + OMNINET_HEADERLEN;
156	data_len = min_t(size_t, urb->actual_length - OMNINET_HEADERLEN,
157								hdr->oh_len);
158	tty_insert_flip_string(&port->port, data, data_len);
159	tty_flip_buffer_push(&port->port);
160}
161
162static int omninet_write(struct tty_struct *tty, struct usb_serial_port *port,
163					const unsigned char *buf, int count)
164{
165	struct usb_serial *serial = port->serial;
166	struct usb_serial_port *wport = serial->port[1];
167
168	struct omninet_data *od = usb_get_serial_port_data(port);
169	struct omninet_header *header = (struct omninet_header *)
170					wport->write_urb->transfer_buffer;
171
172	int			result;
173
174	if (count == 0) {
175		dev_dbg(&port->dev, "%s - write request of 0 bytes\n", __func__);
176		return 0;
177	}
178
179	if (!test_and_clear_bit(0, &port->write_urbs_free)) {
180		dev_dbg(&port->dev, "%s - already writing\n", __func__);
181		return 0;
182	}
183
184	count = (count > OMNINET_PAYLOADSIZE) ? OMNINET_PAYLOADSIZE : count;
185
186	memcpy(wport->write_urb->transfer_buffer + OMNINET_HEADERLEN,
187								buf, count);
188
189	usb_serial_debug_data(&port->dev, __func__, count,
190			      wport->write_urb->transfer_buffer);
191
192	header->oh_seq 	= od->od_outseq++;
193	header->oh_len 	= count;
194	header->oh_xxx  = 0x03;
195	header->oh_pad 	= 0x00;
196
197	/* send the data out the bulk port, always 64 bytes */
198	wport->write_urb->transfer_buffer_length = OMNINET_BULKOUTSIZE;
199
200	result = usb_submit_urb(wport->write_urb, GFP_ATOMIC);
201	if (result) {
202		set_bit(0, &wport->write_urbs_free);
203		dev_err_console(port,
204			"%s - failed submitting write urb, error %d\n",
205			__func__, result);
206	} else
207		result = count;
208
209	return result;
210}
211
212
213static int omninet_write_room(struct tty_struct *tty)
214{
215	struct usb_serial_port *port = tty->driver_data;
216	struct usb_serial 	*serial = port->serial;
217	struct usb_serial_port 	*wport 	= serial->port[1];
218
219	int room = 0; /* Default: no room */
220
221	if (test_bit(0, &wport->write_urbs_free))
222		room = wport->bulk_out_size - OMNINET_HEADERLEN;
223
224	dev_dbg(&port->dev, "%s - returns %d\n", __func__, room);
225
226	return room;
227}
228
229static void omninet_write_bulk_callback(struct urb *urb)
230{
231/*	struct omninet_header	*header = (struct omninet_header  *)
232						urb->transfer_buffer; */
233	struct usb_serial_port 	*port   =  urb->context;
234	int status = urb->status;
235
236	set_bit(0, &port->write_urbs_free);
237	if (status) {
238		dev_dbg(&port->dev, "%s - nonzero write bulk status received: %d\n",
239			__func__, status);
240		return;
241	}
242
243	usb_serial_port_softint(port);
244}
245
246
247static void omninet_disconnect(struct usb_serial *serial)
248{
249	struct usb_serial_port *wport = serial->port[1];
250
251	usb_kill_urb(wport->write_urb);
252}
253
254module_usb_serial_driver(serial_drivers, id_table);
255
256MODULE_AUTHOR(DRIVER_AUTHOR);
257MODULE_DESCRIPTION(DRIVER_DESC);
258MODULE_LICENSE("GPL");
259