xref: /openbmc/linux/drivers/usb/serial/omninet.c (revision fc28ab18)
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_attach(struct usb_serial *serial);
42 static int omninet_port_probe(struct usb_serial_port *port);
43 static int omninet_port_remove(struct usb_serial_port *port);
44 
45 static const struct usb_device_id id_table[] = {
46 	{ USB_DEVICE(ZYXEL_VENDOR_ID, ZYXEL_OMNINET_ID) },
47 	{ USB_DEVICE(ZYXEL_VENDOR_ID, BT_IGNITIONPRO_ID) },
48 	{ }						/* Terminating entry */
49 };
50 MODULE_DEVICE_TABLE(usb, id_table);
51 
52 static struct usb_serial_driver zyxel_omninet_device = {
53 	.driver = {
54 		.owner =	THIS_MODULE,
55 		.name =		"omninet",
56 	},
57 	.description =		"ZyXEL - omni.net lcd plus usb",
58 	.id_table =		id_table,
59 	.num_ports =		1,
60 	.attach =		omninet_attach,
61 	.port_probe =		omninet_port_probe,
62 	.port_remove =		omninet_port_remove,
63 	.open =			omninet_open,
64 	.write =		omninet_write,
65 	.write_room =		omninet_write_room,
66 	.write_bulk_callback =	omninet_write_bulk_callback,
67 	.process_read_urb =	omninet_process_read_urb,
68 	.disconnect =		omninet_disconnect,
69 };
70 
71 static struct usb_serial_driver * const serial_drivers[] = {
72 	&zyxel_omninet_device, NULL
73 };
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.
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 transmitted 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 transmitted frames
93  *	0: handshaking, unknown, usually set to 1 in transmitted 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 struct omninet_header {
99 	__u8	oh_seq;
100 	__u8	oh_len;
101 	__u8	oh_xxx;
102 	__u8	oh_pad;
103 };
104 
105 struct omninet_data {
106 	__u8	od_outseq;	/* Sequence number for bulk_out URBs */
107 };
108 
109 static int omninet_attach(struct usb_serial *serial)
110 {
111 	/* The second bulk-out endpoint is used for writing. */
112 	if (serial->num_bulk_out < 2) {
113 		dev_err(&serial->interface->dev, "missing endpoints\n");
114 		return -ENODEV;
115 	}
116 
117 	return 0;
118 }
119 
120 static int omninet_port_probe(struct usb_serial_port *port)
121 {
122 	struct omninet_data *od;
123 
124 	od = kzalloc(sizeof(*od), GFP_KERNEL);
125 	if (!od)
126 		return -ENOMEM;
127 
128 	usb_set_serial_port_data(port, od);
129 
130 	return 0;
131 }
132 
133 static int omninet_port_remove(struct usb_serial_port *port)
134 {
135 	struct omninet_data *od;
136 
137 	od = usb_get_serial_port_data(port);
138 	kfree(od);
139 
140 	return 0;
141 }
142 
143 static int omninet_open(struct tty_struct *tty, struct usb_serial_port *port)
144 {
145 	struct usb_serial	*serial = port->serial;
146 	struct usb_serial_port	*wport;
147 
148 	wport = serial->port[1];
149 	tty_port_tty_set(&wport->port, tty);
150 
151 	return usb_serial_generic_open(tty, port);
152 }
153 
154 #define OMNINET_HEADERLEN	4
155 #define OMNINET_BULKOUTSIZE	64
156 #define OMNINET_PAYLOADSIZE	(OMNINET_BULKOUTSIZE - OMNINET_HEADERLEN)
157 
158 static void omninet_process_read_urb(struct urb *urb)
159 {
160 	struct usb_serial_port *port = urb->context;
161 	const struct omninet_header *hdr = urb->transfer_buffer;
162 	const unsigned char *data;
163 	size_t data_len;
164 
165 	if (urb->actual_length <= OMNINET_HEADERLEN || !hdr->oh_len)
166 		return;
167 
168 	data = (char *)urb->transfer_buffer + OMNINET_HEADERLEN;
169 	data_len = min_t(size_t, urb->actual_length - OMNINET_HEADERLEN,
170 								hdr->oh_len);
171 	tty_insert_flip_string(&port->port, data, data_len);
172 	tty_flip_buffer_push(&port->port);
173 }
174 
175 static int omninet_write(struct tty_struct *tty, struct usb_serial_port *port,
176 					const unsigned char *buf, int count)
177 {
178 	struct usb_serial *serial = port->serial;
179 	struct usb_serial_port *wport = serial->port[1];
180 
181 	struct omninet_data *od = usb_get_serial_port_data(port);
182 	struct omninet_header *header = (struct omninet_header *)
183 					wport->write_urb->transfer_buffer;
184 
185 	int			result;
186 
187 	if (count == 0) {
188 		dev_dbg(&port->dev, "%s - write request of 0 bytes\n", __func__);
189 		return 0;
190 	}
191 
192 	if (!test_and_clear_bit(0, &port->write_urbs_free)) {
193 		dev_dbg(&port->dev, "%s - already writing\n", __func__);
194 		return 0;
195 	}
196 
197 	count = (count > OMNINET_PAYLOADSIZE) ? OMNINET_PAYLOADSIZE : count;
198 
199 	memcpy(wport->write_urb->transfer_buffer + OMNINET_HEADERLEN,
200 								buf, count);
201 
202 	usb_serial_debug_data(&port->dev, __func__, count,
203 			      wport->write_urb->transfer_buffer);
204 
205 	header->oh_seq 	= od->od_outseq++;
206 	header->oh_len 	= count;
207 	header->oh_xxx  = 0x03;
208 	header->oh_pad 	= 0x00;
209 
210 	/* send the data out the bulk port, always 64 bytes */
211 	wport->write_urb->transfer_buffer_length = OMNINET_BULKOUTSIZE;
212 
213 	result = usb_submit_urb(wport->write_urb, GFP_ATOMIC);
214 	if (result) {
215 		set_bit(0, &wport->write_urbs_free);
216 		dev_err_console(port,
217 			"%s - failed submitting write urb, error %d\n",
218 			__func__, result);
219 	} else
220 		result = count;
221 
222 	return result;
223 }
224 
225 
226 static int omninet_write_room(struct tty_struct *tty)
227 {
228 	struct usb_serial_port *port = tty->driver_data;
229 	struct usb_serial 	*serial = port->serial;
230 	struct usb_serial_port 	*wport 	= serial->port[1];
231 
232 	int room = 0; /* Default: no room */
233 
234 	if (test_bit(0, &wport->write_urbs_free))
235 		room = wport->bulk_out_size - OMNINET_HEADERLEN;
236 
237 	dev_dbg(&port->dev, "%s - returns %d\n", __func__, room);
238 
239 	return room;
240 }
241 
242 static void omninet_write_bulk_callback(struct urb *urb)
243 {
244 /*	struct omninet_header	*header = (struct omninet_header  *)
245 						urb->transfer_buffer; */
246 	struct usb_serial_port 	*port   =  urb->context;
247 	int status = urb->status;
248 
249 	set_bit(0, &port->write_urbs_free);
250 	if (status) {
251 		dev_dbg(&port->dev, "%s - nonzero write bulk status received: %d\n",
252 			__func__, status);
253 		return;
254 	}
255 
256 	usb_serial_port_softint(port);
257 }
258 
259 
260 static void omninet_disconnect(struct usb_serial *serial)
261 {
262 	struct usb_serial_port *wport = serial->port[1];
263 
264 	usb_kill_urb(wport->write_urb);
265 }
266 
267 module_usb_serial_driver(serial_drivers, id_table);
268 
269 MODULE_AUTHOR(DRIVER_AUTHOR);
270 MODULE_DESCRIPTION(DRIVER_DESC);
271 MODULE_LICENSE("GPL");
272