drivers/usb/serial/omninet.c

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