drivers/usb/serial/symbolserial.c

   1 /*
   2  * Symbol USB barcode to serial driver
   3  *
   4  * Copyright (C) 2009 Greg Kroah-Hartman <gregkh@suse.de>
   5  * Copyright (C) 2009 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 const struct usb_device_id id_table[] = {
  25         { USB_DEVICE(0x05e0, 0x0600) },
  26         { },
  27 };
  28 MODULE_DEVICE_TABLE(usb, id_table);
  29
  30 /* This structure holds all of the individual device information */
  31 struct symbol_private {
  32         struct usb_device *udev;
  33         struct usb_serial *serial;
  34         struct usb_serial_port *port;
  35         unsigned char *int_buffer;
  36         struct urb *int_urb;
  37         int buffer_size;
  38         u8 bInterval;
  39         u8 int_address;
  40         spinlock_t lock;        /* protects the following flags */
  41         bool throttled;
  42         bool actually_throttled;
  43         bool rts;
  44 };
  45
  46 static void symbol_int_callback(struct urb *urb)
  47 {
  48         struct symbol_private *priv = urb->context;
  49         unsigned char *data = urb->transfer_buffer;
  50         struct usb_serial_port *port = priv->port;
  51         int status = urb->status;
  52         struct tty_struct *tty;
  53         int result;
  54         int available_room = 0;
  55         int data_length;
  56
  57         dbg("%s - port %d", __func__, port->number);
  58
  59         switch (status) {
  60         case 0:
  61                 /* success */
  62                 break;
  63         case -ECONNRESET:
  64         case -ENOENT:
  65         case -ESHUTDOWN:
  66                 /* this urb is terminated, clean up */
  67                 dbg("%s - urb shutting down with status: %d",
  68                     __func__, status);
  69                 return;
  70         default:
  71                 dbg("%s - nonzero urb status received: %d",
  72                     __func__, status);
  73                 goto exit;
  74         }
  75
  76         usb_serial_debug_data(debug, &port->dev, __func__, urb->actual_length,
  77                               data);
  78
  79         if (urb->actual_length > 1) {
  80                 data_length = urb->actual_length - 1;
  81
  82                 /*
  83                  * Data from the device comes with a 1 byte header:
  84                  *
  85                  * <size of data>data...
  86                  *      This is real data to be sent to the tty layer
  87                  * we pretty much just ignore the size and send everything
  88                  * else to the tty layer.
  89                  */
  90                 tty = tty_port_tty_get(&port->port);
  91                 if (tty) {
  92                         available_room = tty_buffer_request_room(tty,
  93                                                         data_length);
  94                         if (available_room) {
  95                                 tty_insert_flip_string(tty, &data[1],
  96                                                        available_room);
  97                                 tty_flip_buffer_push(tty);
  98                         }
  99                         tty_kref_put(tty);
 100                 }
 101         } else {
 102                 dev_dbg(&priv->udev->dev,
 103                         "Improper ammount of data received from the device, "
 104                         "%d bytes", urb->actual_length);
 105         }
 106
 107 exit:
 108         spin_lock(&priv->lock);
 109
 110         /* Continue trying to always read if we should */
 111         if (!priv->throttled) {
 112                 usb_fill_int_urb(priv->int_urb, priv->udev,
 113                                  usb_rcvintpipe(priv->udev,
 114                                                 priv->int_address),
 115                                  priv->int_buffer, priv->buffer_size,
 116                                  symbol_int_callback, priv, priv->bInterval);
 117                 result = usb_submit_urb(priv->int_urb, GFP_ATOMIC);
 118                 if (result)
 119                         dev_err(&port->dev,
 120                             "%s - failed resubmitting read urb, error %d\n",
 121                                                         __func__, result);
 122         } else
 123                 priv->actually_throttled = true;
 124         spin_unlock(&priv->lock);
 125 }
 126
 127 static int symbol_open(struct tty_struct *tty, struct usb_serial_port *port)
 128 {
 129         struct symbol_private *priv = usb_get_serial_data(port->serial);
 130         unsigned long flags;
 131         int result = 0;
 132
 133         dbg("%s - port %d", __func__, port->number);
 134
 135         spin_lock_irqsave(&priv->lock, flags);
 136         priv->throttled = false;
 137         priv->actually_throttled = false;
 138         priv->port = port;
 139         spin_unlock_irqrestore(&priv->lock, flags);
 140
 141         /* Start reading from the device */
 142         usb_fill_int_urb(priv->int_urb, priv->udev,
 143                          usb_rcvintpipe(priv->udev, priv->int_address),
 144                          priv->int_buffer, priv->buffer_size,
 145                          symbol_int_callback, priv, priv->bInterval);
 146         result = usb_submit_urb(priv->int_urb, GFP_KERNEL);
 147         if (result)
 148                 dev_err(&port->dev,
 149                         "%s - failed resubmitting read urb, error %d\n",
 150                         __func__, result);
 151         return result;
 152 }
 153
 154 static void symbol_close(struct usb_serial_port *port)
 155 {
 156         struct symbol_private *priv = usb_get_serial_data(port->serial);
 157
 158         dbg("%s - port %d", __func__, port->number);
 159
 160         /* shutdown our urbs */
 161         usb_kill_urb(priv->int_urb);
 162 }
 163
 164 static void symbol_throttle(struct tty_struct *tty)
 165 {
 166         struct usb_serial_port *port = tty->driver_data;
 167         struct symbol_private *priv = usb_get_serial_data(port->serial);
 168
 169         dbg("%s - port %d", __func__, port->number);
 170         spin_lock_irq(&priv->lock);
 171         priv->throttled = true;
 172         spin_unlock_irq(&priv->lock);
 173 }
 174
 175 static void symbol_unthrottle(struct tty_struct *tty)
 176 {
 177         struct usb_serial_port *port = tty->driver_data;
 178         struct symbol_private *priv = usb_get_serial_data(port->serial);
 179         int result;
 180         bool was_throttled;
 181
 182         dbg("%s - port %d", __func__, port->number);
 183
 184         spin_lock_irq(&priv->lock);
 185         priv->throttled = false;
 186         was_throttled = priv->actually_throttled;
 187         priv->actually_throttled = false;
 188         spin_unlock_irq(&priv->lock);
 189
 190         priv->int_urb->dev = port->serial->dev;
 191         if (was_throttled) {
 192                 result = usb_submit_urb(priv->int_urb, GFP_KERNEL);
 193                 if (result)
 194                         dev_err(&port->dev,
 195                                 "%s - failed submitting read urb, error %d\n",
 196                                                         __func__, result);
 197         }
 198 }
 199
 200 static int symbol_startup(struct usb_serial *serial)
 201 {
 202         struct symbol_private *priv;
 203         struct usb_host_interface *intf;
 204         int i;
 205         int retval = -ENOMEM;
 206         bool int_in_found = false;
 207
 208         /* create our private serial structure */
 209         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 210         if (priv == NULL) {
 211                 dev_err(&serial->dev->dev, "%s - Out of memory\n", __func__);
 212                 return -ENOMEM;
 213         }
 214         spin_lock_init(&priv->lock);
 215         priv->serial = serial;
 216         priv->port = serial->port[0];
 217         priv->udev = serial->dev;
 218
 219         /* find our interrupt endpoint */
 220         intf = serial->interface->altsetting;
 221         for (i = 0; i < intf->desc.bNumEndpoints; ++i) {
 222                 struct usb_endpoint_descriptor *endpoint;
 223
 224                 endpoint = &intf->endpoint[i].desc;
 225                 if (!usb_endpoint_is_int_in(endpoint))
 226                         continue;
 227
 228                 priv->int_urb = usb_alloc_urb(0, GFP_KERNEL);
 229                 if (!priv->int_urb) {
 230                         dev_err(&priv->udev->dev, "out of memory\n");
 231                         goto error;
 232                 }
 233
 234                 priv->buffer_size = le16_to_cpu(endpoint->wMaxPacketSize) * 2;
 235                 priv->int_buffer = kmalloc(priv->buffer_size, GFP_KERNEL);
 236                 if (!priv->int_buffer) {
 237                         dev_err(&priv->udev->dev, "out of memory\n");
 238                         goto error;
 239                 }
 240
 241                 priv->int_address = endpoint->bEndpointAddress;
 242                 priv->bInterval = endpoint->bInterval;
 243
 244                 /* set up our int urb */
 245                 usb_fill_int_urb(priv->int_urb, priv->udev,
 246                                  usb_rcvintpipe(priv->udev,
 247                                                 endpoint->bEndpointAddress),
 248                                  priv->int_buffer, priv->buffer_size,
 249                                  symbol_int_callback, priv, priv->bInterval);
 250
 251                 int_in_found = true;
 252                 break;
 253                 }
 254
 255         if (!int_in_found) {
 256                 dev_err(&priv->udev->dev,
 257                         "Error - the proper endpoints were not found!\n");
 258                 goto error;
 259         }
 260
 261         usb_set_serial_data(serial, priv);
 262         return 0;
 263
 264 error:
 265         usb_free_urb(priv->int_urb);
 266         kfree(priv->int_buffer);
 267         kfree(priv);
 268         return retval;
 269 }
 270
 271 static void symbol_disconnect(struct usb_serial *serial)
 272 {
 273         struct symbol_private *priv = usb_get_serial_data(serial);
 274
 275         dbg("%s", __func__);
 276
 277         usb_kill_urb(priv->int_urb);
 278         usb_free_urb(priv->int_urb);
 279 }
 280
 281 static void symbol_release(struct usb_serial *serial)
 282 {
 283         struct symbol_private *priv = usb_get_serial_data(serial);
 284
 285         dbg("%s", __func__);
 286
 287         kfree(priv->int_buffer);
 288         kfree(priv);
 289 }
 290
 291 static struct usb_driver symbol_driver = {
 292         .name =                 "symbol",
 293         .probe =                usb_serial_probe,
 294         .disconnect =           usb_serial_disconnect,
 295         .id_table =             id_table,
 296         .no_dynamic_id =        1,
 297 };
 298
 299 static struct usb_serial_driver symbol_device = {
 300         .driver = {
 301                 .owner =        THIS_MODULE,
 302                 .name =         "symbol",
 303         },
 304         .id_table =             id_table,
 305         .usb_driver =           &symbol_driver,
 306         .num_ports =            1,
 307         .attach =               symbol_startup,
 308         .open =                 symbol_open,
 309         .close =                symbol_close,
 310         .disconnect =           symbol_disconnect,
 311         .release =              symbol_release,
 312         .throttle =             symbol_throttle,
 313         .unthrottle =           symbol_unthrottle,
 314 };
 315
 316 static int __init symbol_init(void)
 317 {
 318         int retval;
 319
 320         retval = usb_serial_register(&symbol_device);
 321         if (retval)
 322                 return retval;
 323         retval = usb_register(&symbol_driver);
 324         if (retval)
 325                 usb_serial_deregister(&symbol_device);
 326         return retval;
 327 }
 328
 329 static void __exit symbol_exit(void)
 330 {
 331         usb_deregister(&symbol_driver);
 332         usb_serial_deregister(&symbol_device);
 333 }
 334
 335 module_init(symbol_init);
 336 module_exit(symbol_exit);
 337 MODULE_LICENSE("GPL");
 338
 339 module_param(debug, bool, S_IRUGO | S_IWUSR);
 340 MODULE_PARM_DESC(debug, "Debug enabled or not");