xref: /openbmc/linux/drivers/usb/serial/omninet.c (revision 54cbac81)
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/init.h>
17 #include <linux/slab.h>
18 #include <linux/tty.h>
19 #include <linux/tty_driver.h>
20 #include <linux/tty_flip.h>
21 #include <linux/module.h>
22 #include <linux/uaccess.h>
23 #include <linux/usb.h>
24 #include <linux/usb/serial.h>
25 
26 #define DRIVER_AUTHOR "Alessandro Zummo"
27 #define DRIVER_DESC "USB ZyXEL omni.net LCD PLUS Driver"
28 
29 #define ZYXEL_VENDOR_ID		0x0586
30 #define ZYXEL_OMNINET_ID	0x1000
31 /* This one seems to be a re-branded ZyXEL device */
32 #define BT_IGNITIONPRO_ID	0x2000
33 
34 /* function prototypes */
35 static int  omninet_open(struct tty_struct *tty, struct usb_serial_port *port);
36 static void omninet_close(struct usb_serial_port *port);
37 static void omninet_read_bulk_callback(struct urb *urb);
38 static void omninet_write_bulk_callback(struct urb *urb);
39 static int  omninet_write(struct tty_struct *tty, struct usb_serial_port *port,
40 				const unsigned char *buf, int count);
41 static int  omninet_write_room(struct tty_struct *tty);
42 static void omninet_disconnect(struct usb_serial *serial);
43 static int omninet_port_probe(struct usb_serial_port *port);
44 static int omninet_port_remove(struct usb_serial_port *port);
45 
46 static const struct usb_device_id id_table[] = {
47 	{ USB_DEVICE(ZYXEL_VENDOR_ID, ZYXEL_OMNINET_ID) },
48 	{ USB_DEVICE(ZYXEL_VENDOR_ID, BT_IGNITIONPRO_ID) },
49 	{ }						/* Terminating entry */
50 };
51 MODULE_DEVICE_TABLE(usb, id_table);
52 
53 static struct usb_serial_driver zyxel_omninet_device = {
54 	.driver = {
55 		.owner =	THIS_MODULE,
56 		.name =		"omninet",
57 	},
58 	.description =		"ZyXEL - omni.net lcd plus usb",
59 	.id_table =		id_table,
60 	.num_ports =		1,
61 	.port_probe =		omninet_port_probe,
62 	.port_remove =		omninet_port_remove,
63 	.open =			omninet_open,
64 	.close =		omninet_close,
65 	.write =		omninet_write,
66 	.write_room =		omninet_write_room,
67 	.read_bulk_callback =	omninet_read_bulk_callback,
68 	.write_bulk_callback =	omninet_write_bulk_callback,
69 	.disconnect =		omninet_disconnect,
70 };
71 
72 static struct usb_serial_driver * const serial_drivers[] = {
73 	&zyxel_omninet_device, NULL
74 };
75 
76 
77 /* The protocol.
78  *
79  * The omni.net always exchange 64 bytes of data with the host. The first
80  * four bytes are the control header, you can see it in the above structure.
81  *
82  * oh_seq is a sequence number. Don't know if/how it's used.
83  * oh_len is the length of the data bytes in the packet.
84  * oh_xxx Bit-mapped, related to handshaking and status info.
85  *	I normally set it to 0x03 in trasmitted frames.
86  *	7: Active when the TA is in a CONNECTed state.
87  *	6: unknown
88  *	5: handshaking, unknown
89  *	4: handshaking, unknown
90  *	3: unknown, usually 0
91  *	2: unknown, usually 0
92  *	1: handshaking, unknown, usually set to 1 in trasmitted frames
93  *	0: handshaking, unknown, usually set to 1 in trasmitted frames
94  * oh_pad Probably a pad byte.
95  *
96  * After the header you will find data bytes if oh_len was greater than zero.
97  *
98  */
99 
100 struct omninet_header {
101 	__u8	oh_seq;
102 	__u8	oh_len;
103 	__u8	oh_xxx;
104 	__u8	oh_pad;
105 };
106 
107 struct omninet_data {
108 	__u8	od_outseq;	/* Sequence number for bulk_out URBs */
109 };
110 
111 static int omninet_port_probe(struct usb_serial_port *port)
112 {
113 	struct omninet_data *od;
114 
115 	od = kmalloc(sizeof(struct omninet_data), GFP_KERNEL);
116 	if (!od)
117 		return -ENOMEM;
118 
119 	usb_set_serial_port_data(port, od);
120 
121 	return 0;
122 }
123 
124 static int omninet_port_remove(struct usb_serial_port *port)
125 {
126 	struct omninet_data *od;
127 
128 	od = usb_get_serial_port_data(port);
129 	kfree(od);
130 
131 	return 0;
132 }
133 
134 static int omninet_open(struct tty_struct *tty, struct usb_serial_port *port)
135 {
136 	struct usb_serial	*serial = port->serial;
137 	struct usb_serial_port	*wport;
138 	int			result = 0;
139 
140 	wport = serial->port[1];
141 	tty_port_tty_set(&wport->port, tty);
142 
143 	/* Start reading from the device */
144 	result = usb_submit_urb(port->read_urb, GFP_KERNEL);
145 	if (result)
146 		dev_err(&port->dev,
147 			"%s - failed submitting read urb, error %d\n",
148 			__func__, result);
149 	return result;
150 }
151 
152 static void omninet_close(struct usb_serial_port *port)
153 {
154 	usb_kill_urb(port->read_urb);
155 }
156 
157 
158 #define OMNINET_DATAOFFSET	0x04
159 #define OMNINET_HEADERLEN	sizeof(struct omninet_header)
160 #define OMNINET_BULKOUTSIZE 	(64 - OMNINET_HEADERLEN)
161 
162 static void omninet_read_bulk_callback(struct urb *urb)
163 {
164 	struct usb_serial_port 	*port 	= urb->context;
165 	unsigned char 		*data 	= urb->transfer_buffer;
166 	struct omninet_header 	*header = (struct omninet_header *) &data[0];
167 	int status = urb->status;
168 	int result;
169 
170 	if (status) {
171 		dev_dbg(&port->dev, "%s - nonzero read bulk status received: %d\n",
172 			__func__, status);
173 		return;
174 	}
175 
176 	if (urb->actual_length && header->oh_len) {
177 		struct tty_struct *tty = tty_port_tty_get(&port->port);
178 		if (tty) {
179 			tty_insert_flip_string(tty, data + OMNINET_DATAOFFSET,
180 							header->oh_len);
181 			tty_flip_buffer_push(tty);
182 			tty_kref_put(tty);
183 		}
184 	}
185 
186 	/* Continue trying to always read  */
187 	result = usb_submit_urb(urb, GFP_ATOMIC);
188 	if (result)
189 		dev_err(&port->dev,
190 			"%s - failed resubmitting read urb, error %d\n",
191 			__func__, result);
192 }
193 
194 static int omninet_write(struct tty_struct *tty, struct usb_serial_port *port,
195 					const unsigned char *buf, int count)
196 {
197 	struct usb_serial *serial = port->serial;
198 	struct usb_serial_port *wport = serial->port[1];
199 
200 	struct omninet_data *od = usb_get_serial_port_data(port);
201 	struct omninet_header *header = (struct omninet_header *)
202 					wport->write_urb->transfer_buffer;
203 
204 	int			result;
205 
206 	if (count == 0) {
207 		dev_dbg(&port->dev, "%s - write request of 0 bytes\n", __func__);
208 		return 0;
209 	}
210 
211 	if (!test_and_clear_bit(0, &port->write_urbs_free)) {
212 		dev_dbg(&port->dev, "%s - already writing\n", __func__);
213 		return 0;
214 	}
215 
216 	count = (count > OMNINET_BULKOUTSIZE) ? OMNINET_BULKOUTSIZE : count;
217 
218 	memcpy(wport->write_urb->transfer_buffer + OMNINET_DATAOFFSET,
219 								buf, count);
220 
221 	usb_serial_debug_data(&port->dev, __func__, count,
222 			      wport->write_urb->transfer_buffer);
223 
224 	header->oh_seq 	= od->od_outseq++;
225 	header->oh_len 	= count;
226 	header->oh_xxx  = 0x03;
227 	header->oh_pad 	= 0x00;
228 
229 	/* send the data out the bulk port, always 64 bytes */
230 	wport->write_urb->transfer_buffer_length = 64;
231 
232 	result = usb_submit_urb(wport->write_urb, GFP_ATOMIC);
233 	if (result) {
234 		set_bit(0, &wport->write_urbs_free);
235 		dev_err_console(port,
236 			"%s - failed submitting write urb, error %d\n",
237 			__func__, result);
238 	} else
239 		result = count;
240 
241 	return result;
242 }
243 
244 
245 static int omninet_write_room(struct tty_struct *tty)
246 {
247 	struct usb_serial_port *port = tty->driver_data;
248 	struct usb_serial 	*serial = port->serial;
249 	struct usb_serial_port 	*wport 	= serial->port[1];
250 
251 	int room = 0; /* Default: no room */
252 
253 	if (test_bit(0, &wport->write_urbs_free))
254 		room = wport->bulk_out_size - OMNINET_HEADERLEN;
255 
256 	dev_dbg(&port->dev, "%s - returns %d\n", __func__, room);
257 
258 	return room;
259 }
260 
261 static void omninet_write_bulk_callback(struct urb *urb)
262 {
263 /*	struct omninet_header	*header = (struct omninet_header  *)
264 						urb->transfer_buffer; */
265 	struct usb_serial_port 	*port   =  urb->context;
266 	int status = urb->status;
267 
268 	set_bit(0, &port->write_urbs_free);
269 	if (status) {
270 		dev_dbg(&port->dev, "%s - nonzero write bulk status received: %d\n",
271 			__func__, status);
272 		return;
273 	}
274 
275 	usb_serial_port_softint(port);
276 }
277 
278 
279 static void omninet_disconnect(struct usb_serial *serial)
280 {
281 	struct usb_serial_port *wport = serial->port[1];
282 
283 	usb_kill_urb(wport->write_urb);
284 }
285 
286 module_usb_serial_driver(serial_drivers, id_table);
287 
288 MODULE_AUTHOR(DRIVER_AUTHOR);
289 MODULE_DESCRIPTION(DRIVER_DESC);
290 MODULE_LICENSE("GPL");
291