xref: /openbmc/linux/drivers/usb/serial/omninet.c (revision 9cfc5c90)
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 */
34 static int  omninet_open(struct tty_struct *tty, struct usb_serial_port *port);
35 static void omninet_process_read_urb(struct urb *urb);
36 static void omninet_write_bulk_callback(struct urb *urb);
37 static int  omninet_write(struct tty_struct *tty, struct usb_serial_port *port,
38 				const unsigned char *buf, int count);
39 static int  omninet_write_room(struct tty_struct *tty);
40 static void omninet_disconnect(struct usb_serial *serial);
41 static int omninet_port_probe(struct usb_serial_port *port);
42 static int omninet_port_remove(struct usb_serial_port *port);
43 
44 static 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 };
49 MODULE_DEVICE_TABLE(usb, id_table);
50 
51 static 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 
69 static 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  */
96 struct omninet_header {
97 	__u8	oh_seq;
98 	__u8	oh_len;
99 	__u8	oh_xxx;
100 	__u8	oh_pad;
101 };
102 
103 struct omninet_data {
104 	__u8	od_outseq;	/* Sequence number for bulk_out URBs */
105 };
106 
107 static 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 
120 static 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 
130 static 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 
145 static 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 
162 static 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 
213 static 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 
229 static 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 
247 static 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 
254 module_usb_serial_driver(serial_drivers, id_table);
255 
256 MODULE_AUTHOR(DRIVER_AUTHOR);
257 MODULE_DESCRIPTION(DRIVER_DESC);
258 MODULE_LICENSE("GPL");
259