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/slab.h>
  16 #include <linux/tty_driver.h>
  17 #include <linux/tty_flip.h>
  18 #include <linux/module.h>
  19 #include <linux/usb.h>
  20 #include <linux/usb/serial.h>
  21 #include <linux/uaccess.h>
  22
  23 static int debug;
  24
  25 static const struct usb_device_id id_table[] = {
  26         { USB_DEVICE(0x05e0, 0x0600) },
  27         { },
  28 };
  29 MODULE_DEVICE_TABLE(usb, id_table);
  30
  31 /* This structure holds all of the individual device information */
  32 struct symbol_private {
  33         struct usb_device *udev;
  34         struct usb_serial *serial;
  35         struct usb_serial_port *port;
  36         unsigned char *int_buffer;
  37         struct urb *int_urb;
  38         int buffer_size;
  39         u8 bInterval;
  40         u8 int_address;
  41         spinlock_t lock;        /* protects the following flags */
  42         bool throttled;
  43         bool actually_throttled;
  44         bool rts;
  45 };
  46
  47 static void symbol_int_callback(struct urb *urb)
  48 {
  49         struct symbol_private *priv = urb->context;
  50         unsigned char *data = urb->transfer_buffer;
  51         struct usb_serial_port *port = priv->port;
  52         int status = urb->status;
  53         struct tty_struct *tty;
  54         int result;
  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                         tty_insert_flip_string(tty, &data[1], data_length);
  93                         tty_flip_buffer_push(tty);
  94                         tty_kref_put(tty);
  95                 }
  96         } else {
  97                 dev_dbg(&priv->udev->dev,
  98                         "Improper amount of data received from the device, "
  99                         "%d bytes", urb->actual_length);
 100         }
 101
 102 exit:
 103         spin_lock(&priv->lock);
 104
 105         /* Continue trying to always read if we should */
 106         if (!priv->throttled) {
 107                 usb_fill_int_urb(priv->int_urb, priv->udev,
 108                                  usb_rcvintpipe(priv->udev,
 109                                                 priv->int_address),
 110                                  priv->int_buffer, priv->buffer_size,
 111                                  symbol_int_callback, priv, priv->bInterval);
 112                 result = usb_submit_urb(priv->int_urb, GFP_ATOMIC);
 113                 if (result)
 114                         dev_err(&port->dev,
 115                             "%s - failed resubmitting read urb, error %d\n",
 116                                                         __func__, result);
 117         } else
 118                 priv->actually_throttled = true;
 119         spin_unlock(&priv->lock);
 120 }
 121
 122 static int symbol_open(struct tty_struct *tty, struct usb_serial_port *port)
 123 {
 124         struct symbol_private *priv = usb_get_serial_data(port->serial);
 125         unsigned long flags;
 126         int result = 0;
 127
 128         dbg("%s - port %d", __func__, port->number);
 129
 130         spin_lock_irqsave(&priv->lock, flags);
 131         priv->throttled = false;
 132         priv->actually_throttled = false;
 133         priv->port = port;
 134         spin_unlock_irqrestore(&priv->lock, flags);
 135
 136         /* Start reading from the device */
 137         usb_fill_int_urb(priv->int_urb, priv->udev,
 138                          usb_rcvintpipe(priv->udev, priv->int_address),
 139                          priv->int_buffer, priv->buffer_size,
 140                          symbol_int_callback, priv, priv->bInterval);
 141         result = usb_submit_urb(priv->int_urb, GFP_KERNEL);
 142         if (result)
 143                 dev_err(&port->dev,
 144                         "%s - failed resubmitting read urb, error %d\n",
 145                         __func__, result);
 146         return result;
 147 }
 148
 149 static void symbol_close(struct usb_serial_port *port)
 150 {
 151         struct symbol_private *priv = usb_get_serial_data(port->serial);
 152
 153         dbg("%s - port %d", __func__, port->number);
 154
 155         /* shutdown our urbs */
 156         usb_kill_urb(priv->int_urb);
 157 }
 158
 159 static void symbol_throttle(struct tty_struct *tty)
 160 {
 161         struct usb_serial_port *port = tty->driver_data;
 162         struct symbol_private *priv = usb_get_serial_data(port->serial);
 163
 164         dbg("%s - port %d", __func__, port->number);
 165         spin_lock_irq(&priv->lock);
 166         priv->throttled = true;
 167         spin_unlock_irq(&priv->lock);
 168 }
 169
 170 static void symbol_unthrottle(struct tty_struct *tty)
 171 {
 172         struct usb_serial_port *port = tty->driver_data;
 173         struct symbol_private *priv = usb_get_serial_data(port->serial);
 174         int result;
 175         bool was_throttled;
 176
 177         dbg("%s - port %d", __func__, port->number);
 178
 179         spin_lock_irq(&priv->lock);
 180         priv->throttled = false;
 181         was_throttled = priv->actually_throttled;
 182         priv->actually_throttled = false;
 183         spin_unlock_irq(&priv->lock);
 184
 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 = usb_endpoint_maxp(endpoint) * 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");