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