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