drivers/usb/serial/opticon.c

   1 /*
   2  * Opticon USB barcode to serial driver
   3  *
   4  * Copyright (C) 2008 Greg Kroah-Hartman <gregkh@suse.de>
   5  * Copyright (C) 2008 Novell Inc.
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License version
   9  *      2 as published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/init.h>
  14 #include <linux/tty.h>
  15 #include <linux/tty_driver.h>
  16 #include <linux/tty_flip.h>
  17 #include <linux/module.h>
  18 #include <linux/usb.h>
  19 #include <linux/usb/serial.h>
  20 #include <linux/uaccess.h>
  21
  22 static int debug;
  23
  24 static struct usb_device_id id_table[] = {
  25         { USB_DEVICE(0x065a, 0x0009) },
  26         { },
  27 };
  28 MODULE_DEVICE_TABLE(usb, id_table);
  29
  30 /* This structure holds all of the individual device information */
  31 struct opticon_private {
  32         struct usb_device *udev;
  33         struct usb_serial *serial;
  34         struct usb_serial_port *port;
  35         unsigned char *bulk_in_buffer;
  36         struct urb *bulk_read_urb;
  37         int buffer_size;
  38         u8 bulk_address;
  39         spinlock_t lock;        /* protects the following flags */
  40         bool throttled;
  41         bool actually_throttled;
  42         bool rts;
  43 };
  44
  45 static void opticon_bulk_callback(struct urb *urb)
  46 {
  47         struct opticon_private *priv = urb->context;
  48         unsigned char *data = urb->transfer_buffer;
  49         struct usb_serial_port *port = priv->port;
  50         int status = urb->status;
  51         struct tty_struct *tty;
  52         int result;
  53         int available_room = 0;
  54         int data_length;
  55
  56         dbg("%s - port %d", __func__, port->number);
  57
  58         switch (status) {
  59         case 0:
  60                 /* success */
  61                 break;
  62         case -ECONNRESET:
  63         case -ENOENT:
  64         case -ESHUTDOWN:
  65                 /* this urb is terminated, clean up */
  66                 dbg("%s - urb shutting down with status: %d",
  67                     __func__, status);
  68                 return;
  69         default:
  70                 dbg("%s - nonzero urb status received: %d",
  71                     __func__, status);
  72                 goto exit;
  73         }
  74
  75         usb_serial_debug_data(debug, &port->dev, __func__, urb->actual_length,
  76                               data);
  77
  78         if (urb->actual_length > 2) {
  79                 data_length = urb->actual_length - 2;
  80
  81                 /*
  82                  * Data from the device comes with a 2 byte header:
  83                  *
  84                  * <0x00><0x00>data...
  85                  *      This is real data to be sent to the tty layer
  86                  * <0x00><0x01)level
  87                  *      This is a RTS level change, the third byte is the RTS
  88                  *      value (0 for low, 1 for high).
  89                  */
  90                 if ((data[0] == 0x00) && (data[1] == 0x00)) {
  91                         /* real data, send it to the tty layer */
  92                         tty = tty_port_tty_get(&port->port);
  93                         if (tty) {
  94                                 available_room = tty_buffer_request_room(tty,
  95                                                                 data_length);
  96                                 if (available_room) {
  97                                         tty_insert_flip_string(tty, data,
  98                                                                available_room);
  99                                         tty_flip_buffer_push(tty);
 100                                 }
 101                                 tty_kref_put(tty);
 102                         }
 103                 } else {
 104                         if ((data[0] == 0x00) && (data[1] == 0x01)) {
 105                                 if (data[2] == 0x00)
 106                                         priv->rts = false;
 107                                 else
 108                                         priv->rts = true;
 109                                 /* FIXME change the RTS level */
 110                         } else {
 111                         dev_dbg(&priv->udev->dev,
 112                                 "Unknown data packet received from the device:"
 113                                 " %2x %2x\n",
 114                                 data[0], data[1]);
 115                         }
 116                 }
 117         } else {
 118                 dev_dbg(&priv->udev->dev,
 119                         "Improper ammount of data received from the device, "
 120                         "%d bytes", urb->actual_length);
 121         }
 122
 123 exit:
 124         spin_lock(&priv->lock);
 125
 126         /* Continue trying to always read if we should */
 127         if (!priv->throttled) {
 128                 usb_fill_bulk_urb(priv->bulk_read_urb, priv->udev,
 129                                   usb_rcvbulkpipe(priv->udev,
 130                                                   priv->bulk_address),
 131                                   priv->bulk_in_buffer, priv->buffer_size,
 132                                   opticon_bulk_callback, priv);
 133                 result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
 134                 if (result)
 135                         dev_err(&port->dev,
 136                             "%s - failed resubmitting read urb, error %d\n",
 137                                                         __func__, result);
 138         } else
 139                 priv->actually_throttled = true;
 140         spin_unlock(&priv->lock);
 141 }
 142
 143 static int opticon_open(struct tty_struct *tty, struct usb_serial_port *port,
 144                         struct file *filp)
 145 {
 146         struct opticon_private *priv = usb_get_serial_data(port->serial);
 147         unsigned long flags;
 148         int result = 0;
 149
 150         dbg("%s - port %d", __func__, port->number);
 151
 152         spin_lock_irqsave(&priv->lock, flags);
 153         priv->throttled = false;
 154         priv->actually_throttled = false;
 155         priv->port = port;
 156         spin_unlock_irqrestore(&priv->lock, flags);
 157
 158         /*
 159          * Force low_latency on so that our tty_push actually forces the data
 160          * through, otherwise it is scheduled, and with high data rates (like
 161          * with OHCI) data can get lost.
 162          */
 163         if (tty)
 164                 tty->low_latency = 1;
 165
 166         /* Start reading from the device */
 167         usb_fill_bulk_urb(priv->bulk_read_urb, priv->udev,
 168                           usb_rcvbulkpipe(priv->udev,
 169                                           priv->bulk_address),
 170                           priv->bulk_in_buffer, priv->buffer_size,
 171                           opticon_bulk_callback, priv);
 172         result = usb_submit_urb(priv->bulk_read_urb, GFP_KERNEL);
 173         if (result)
 174                 dev_err(&port->dev,
 175                         "%s - failed resubmitting read urb, error %d\n",
 176                         __func__, result);
 177         return result;
 178 }
 179
 180 static void opticon_close(struct tty_struct *tty, struct usb_serial_port *port,
 181                           struct file *filp)
 182 {
 183         struct opticon_private *priv = usb_get_serial_data(port->serial);
 184
 185         dbg("%s - port %d", __func__, port->number);
 186
 187         /* shutdown our urbs */
 188         usb_kill_urb(priv->bulk_read_urb);
 189 }
 190
 191 static void opticon_throttle(struct tty_struct *tty)
 192 {
 193         struct usb_serial_port *port = tty->driver_data;
 194         struct opticon_private *priv = usb_get_serial_data(port->serial);
 195         unsigned long flags;
 196
 197         dbg("%s - port %d", __func__, port->number);
 198         spin_lock_irqsave(&priv->lock, flags);
 199         priv->throttled = true;
 200         spin_unlock_irqrestore(&priv->lock, flags);
 201 }
 202
 203
 204 static void opticon_unthrottle(struct tty_struct *tty)
 205 {
 206         struct usb_serial_port *port = tty->driver_data;
 207         struct opticon_private *priv = usb_get_serial_data(port->serial);
 208         unsigned long flags;
 209         int result;
 210
 211         dbg("%s - port %d", __func__, port->number);
 212
 213         spin_lock_irqsave(&priv->lock, flags);
 214         priv->throttled = false;
 215         priv->actually_throttled = false;
 216         spin_unlock_irqrestore(&priv->lock, flags);
 217
 218         priv->bulk_read_urb->dev = port->serial->dev;
 219         result = usb_submit_urb(priv->bulk_read_urb, GFP_ATOMIC);
 220         if (result)
 221                 dev_err(&port->dev,
 222                         "%s - failed submitting read urb, error %d\n",
 223                                                         __func__, result);
 224 }
 225
 226 static int opticon_startup(struct usb_serial *serial)
 227 {
 228         struct opticon_private *priv;
 229         struct usb_host_interface *intf;
 230         int i;
 231         int retval = -ENOMEM;
 232         bool bulk_in_found = false;
 233
 234         /* create our private serial structure */
 235         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 236         if (priv == NULL) {
 237                 dev_err(&serial->dev->dev, "%s - Out of memory\n", __func__);
 238                 return -ENOMEM;
 239         }
 240         spin_lock_init(&priv->lock);
 241         priv->serial = serial;
 242         priv->port = serial->port[0];
 243         priv->udev = serial->dev;
 244
 245         /* find our bulk endpoint */
 246         intf = serial->interface->altsetting;
 247         for (i = 0; i < intf->desc.bNumEndpoints; ++i) {
 248                 struct usb_endpoint_descriptor *endpoint;
 249
 250                 endpoint = &intf->endpoint[i].desc;
 251                 if (!usb_endpoint_is_bulk_in(endpoint))
 252                         continue;
 253
 254                 priv->bulk_read_urb = usb_alloc_urb(0, GFP_KERNEL);
 255                 if (!priv->bulk_read_urb) {
 256                         dev_err(&priv->udev->dev, "out of memory\n");
 257                         goto error;
 258                 }
 259
 260                 priv->buffer_size = le16_to_cpu(endpoint->wMaxPacketSize) * 2;
 261                 priv->bulk_in_buffer = kmalloc(priv->buffer_size, GFP_KERNEL);
 262                 if (!priv->bulk_in_buffer) {
 263                         dev_err(&priv->udev->dev, "out of memory\n");
 264                         goto error;
 265                 }
 266
 267                 priv->bulk_address = endpoint->bEndpointAddress;
 268
 269                 /* set up our bulk urb */
 270                 usb_fill_bulk_urb(priv->bulk_read_urb, priv->udev,
 271                                   usb_rcvbulkpipe(priv->udev,
 272                                                   endpoint->bEndpointAddress),
 273                                   priv->bulk_in_buffer, priv->buffer_size,
 274                                   opticon_bulk_callback, priv);
 275
 276                 bulk_in_found = true;
 277                 break;
 278                 }
 279
 280         if (!bulk_in_found) {
 281                 dev_err(&priv->udev->dev,
 282                         "Error - the proper endpoints were not found!\n");
 283                 goto error;
 284         }
 285
 286         usb_set_serial_data(serial, priv);
 287         return 0;
 288
 289 error:
 290         usb_free_urb(priv->bulk_read_urb);
 291         kfree(priv->bulk_in_buffer);
 292         kfree(priv);
 293         return retval;
 294 }
 295
 296 static void opticon_shutdown(struct usb_serial *serial)
 297 {
 298         struct opticon_private *priv = usb_get_serial_data(serial);
 299
 300         dbg("%s", __func__);
 301
 302         usb_kill_urb(priv->bulk_read_urb);
 303         usb_free_urb(priv->bulk_read_urb);
 304         kfree(priv->bulk_in_buffer);
 305         kfree(priv);
 306         usb_set_serial_data(serial, NULL);
 307 }
 308
 309
 310 static struct usb_driver opticon_driver = {
 311         .name =         "opticon",
 312         .probe =        usb_serial_probe,
 313         .disconnect =   usb_serial_disconnect,
 314         .id_table =     id_table,
 315         .no_dynamic_id =        1,
 316 };
 317
 318 static struct usb_serial_driver opticon_device = {
 319         .driver = {
 320                 .owner =        THIS_MODULE,
 321                 .name =         "opticon",
 322         },
 323         .id_table =             id_table,
 324         .usb_driver =           &opticon_driver,
 325         .num_ports =            1,
 326         .attach =               opticon_startup,
 327         .open =                 opticon_open,
 328         .close =                opticon_close,
 329         .shutdown =             opticon_shutdown,
 330         .throttle =             opticon_throttle,
 331         .unthrottle =           opticon_unthrottle,
 332 };
 333
 334 static int __init opticon_init(void)
 335 {
 336         int retval;
 337
 338         retval = usb_serial_register(&opticon_device);
 339         if (retval)
 340                 return retval;
 341         retval = usb_register(&opticon_driver);
 342         if (retval)
 343                 usb_serial_deregister(&opticon_device);
 344         return retval;
 345 }
 346
 347 static void __exit opticon_exit(void)
 348 {
 349         usb_deregister(&opticon_driver);
 350         usb_serial_deregister(&opticon_device);
 351 }
 352
 353 module_init(opticon_init);
 354 module_exit(opticon_exit);
 355 MODULE_LICENSE("GPL");
 356
 357 module_param(debug, bool, S_IRUGO | S_IWUSR);
 358 MODULE_PARM_DESC(debug, "Debug enabled or not");