1// SPDX-License-Identifier: GPL-2.0
2/*
3 * USB ZyXEL omni.net driver
4 *
5 * Copyright (C) 2013,2017 Johan Hovold <johan@kernel.org>
6 *
7 * See Documentation/usb/usb-serial.rst for more information on using this
8 * driver
9 *
10 * Please report both successes and troubles to the author at omninet@kroah.com
11 */
12
13#include <linux/kernel.h>
14#include <linux/errno.h>
15#include <linux/slab.h>
16#include <linux/tty.h>
17#include <linux/tty_driver.h>
18#include <linux/tty_flip.h>
19#include <linux/module.h>
20#include <linux/uaccess.h>
21#include <linux/usb.h>
22#include <linux/usb/serial.h>
23
24#define DRIVER_AUTHOR "Alessandro Zummo"
25#define DRIVER_DESC "USB ZyXEL omni.net Driver"
26
27#define ZYXEL_VENDOR_ID		0x0586
28#define ZYXEL_OMNINET_ID	0x1000
29#define ZYXEL_OMNI_56K_PLUS_ID	0x1500
30/* This one seems to be a re-branded ZyXEL device */
31#define BT_IGNITIONPRO_ID	0x2000
32
33/* function prototypes */
34static void omninet_process_read_urb(struct urb *urb);
35static int omninet_prepare_write_buffer(struct usb_serial_port *port,
36				void *buf, size_t count);
37static int omninet_calc_num_ports(struct usb_serial *serial,
38				struct usb_serial_endpoints *epds);
39static int omninet_port_probe(struct usb_serial_port *port);
40static void omninet_port_remove(struct usb_serial_port *port);
41
42static const struct usb_device_id id_table[] = {
43	{ USB_DEVICE(ZYXEL_VENDOR_ID, ZYXEL_OMNINET_ID) },
44	{ USB_DEVICE(ZYXEL_VENDOR_ID, ZYXEL_OMNI_56K_PLUS_ID) },
45	{ USB_DEVICE(ZYXEL_VENDOR_ID, BT_IGNITIONPRO_ID) },
46	{ }						/* Terminating entry */
47};
48MODULE_DEVICE_TABLE(usb, id_table);
49
50static struct usb_serial_driver zyxel_omninet_device = {
51	.driver = {
52		.owner =	THIS_MODULE,
53		.name =		"omninet",
54	},
55	.description =		"ZyXEL - omni.net usb",
56	.id_table =		id_table,
57	.num_bulk_out =		2,
58	.calc_num_ports =	omninet_calc_num_ports,
59	.port_probe =		omninet_port_probe,
60	.port_remove =		omninet_port_remove,
61	.process_read_urb =	omninet_process_read_urb,
62	.prepare_write_buffer =	omninet_prepare_write_buffer,
63};
64
65static struct usb_serial_driver * const serial_drivers[] = {
66	&zyxel_omninet_device, NULL
67};
68
69
70/*
71 * The protocol.
72 *
73 * The omni.net always exchange 64 bytes of data with the host. The first
74 * four bytes are the control header.
75 *
76 * oh_seq is a sequence number. Don't know if/how it's used.
77 * oh_len is the length of the data bytes in the packet.
78 * oh_xxx Bit-mapped, related to handshaking and status info.
79 *	I normally set it to 0x03 in transmitted frames.
80 *	7: Active when the TA is in a CONNECTed state.
81 *	6: unknown
82 *	5: handshaking, unknown
83 *	4: handshaking, unknown
84 *	3: unknown, usually 0
85 *	2: unknown, usually 0
86 *	1: handshaking, unknown, usually set to 1 in transmitted frames
87 *	0: handshaking, unknown, usually set to 1 in transmitted frames
88 * oh_pad Probably a pad byte.
89 *
90 * After the header you will find data bytes if oh_len was greater than zero.
91 */
92struct omninet_header {
93	__u8	oh_seq;
94	__u8	oh_len;
95	__u8	oh_xxx;
96	__u8	oh_pad;
97};
98
99struct omninet_data {
100	__u8	od_outseq;	/* Sequence number for bulk_out URBs */
101};
102
103static int omninet_calc_num_ports(struct usb_serial *serial,
104					struct usb_serial_endpoints *epds)
105{
106	/* We need only the second bulk-out for our single-port device. */
107	epds->bulk_out[0] = epds->bulk_out[1];
108	epds->num_bulk_out = 1;
109
110	return 1;
111}
112
113static int omninet_port_probe(struct usb_serial_port *port)
114{
115	struct omninet_data *od;
116
117	od = kzalloc(sizeof(*od), GFP_KERNEL);
118	if (!od)
119		return -ENOMEM;
120
121	usb_set_serial_port_data(port, od);
122
123	return 0;
124}
125
126static void omninet_port_remove(struct usb_serial_port *port)
127{
128	struct omninet_data *od;
129
130	od = usb_get_serial_port_data(port);
131	kfree(od);
132}
133
134#define OMNINET_HEADERLEN	4
135#define OMNINET_BULKOUTSIZE	64
136#define OMNINET_PAYLOADSIZE	(OMNINET_BULKOUTSIZE - OMNINET_HEADERLEN)
137
138static void omninet_process_read_urb(struct urb *urb)
139{
140	struct usb_serial_port *port = urb->context;
141	const struct omninet_header *hdr = urb->transfer_buffer;
142	const unsigned char *data;
143	size_t data_len;
144
145	if (urb->actual_length <= OMNINET_HEADERLEN || !hdr->oh_len)
146		return;
147
148	data = (char *)urb->transfer_buffer + OMNINET_HEADERLEN;
149	data_len = min_t(size_t, urb->actual_length - OMNINET_HEADERLEN,
150								hdr->oh_len);
151	tty_insert_flip_string(&port->port, data, data_len);
152	tty_flip_buffer_push(&port->port);
153}
154
155static int omninet_prepare_write_buffer(struct usb_serial_port *port,
156					void *buf, size_t count)
157{
158	struct omninet_data *od = usb_get_serial_port_data(port);
159	struct omninet_header *header = buf;
160
161	count = min_t(size_t, count, OMNINET_PAYLOADSIZE);
162
163	count = kfifo_out_locked(&port->write_fifo, buf + OMNINET_HEADERLEN,
164			count, &port->lock);
165
166	header->oh_seq = od->od_outseq++;
167	header->oh_len = count;
168	header->oh_xxx = 0x03;
169	header->oh_pad = 0x00;
170
171	/* always 64 bytes */
172	return OMNINET_BULKOUTSIZE;
173}
174
175module_usb_serial_driver(serial_drivers, id_table);
176
177MODULE_AUTHOR(DRIVER_AUTHOR);
178MODULE_DESCRIPTION(DRIVER_DESC);
179MODULE_LICENSE("GPL v2");
180