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 bool 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         switch (status) {
  58         case 0:
  59                 /* success */
  60                 break;
  61         case -ECONNRESET:
  62         case -ENOENT:
  63         case -ESHUTDOWN:
  64                 /* this urb is terminated, clean up */
  65                 dev_dbg(&port->dev, "%s - urb shutting down with status: %d\n",
  66                         __func__, status);
  67                 return;
  68         default:
  69                 dev_dbg(&port->dev, "%s - nonzero urb status received: %d\n",
  70                         __func__, status);
  71                 goto exit;
  72         }
  73
  74         usb_serial_debug_data(debug, &port->dev, __func__, urb->actual_length,
  75                               data);
  76
  77         if (urb->actual_length > 1) {
  78                 data_length = urb->actual_length - 1;
  79
  80                 /*
  81                  * Data from the device comes with a 1 byte header:
  82                  *
  83                  * <size of data>data...
  84                  *      This is real data to be sent to the tty layer
  85                  * we pretty much just ignore the size and send everything
  86                  * else to the tty layer.
  87                  */
  88                 tty = tty_port_tty_get(&port->port);
  89                 if (tty) {
  90                         tty_insert_flip_string(tty, &data[1], data_length);
  91                         tty_flip_buffer_push(tty);
  92                         tty_kref_put(tty);
  93                 }
  94         } else {
  95                 dev_dbg(&priv->udev->dev,
  96                         "Improper amount of data received from the device, "
  97                         "%d bytes", urb->actual_length);
  98         }
  99
 100 exit:
 101         spin_lock(&priv->lock);
 102
 103         /* Continue trying to always read if we should */
 104         if (!priv->throttled) {
 105                 usb_fill_int_urb(priv->int_urb, priv->udev,
 106                                  usb_rcvintpipe(priv->udev,
 107                                                 priv->int_address),
 108                                  priv->int_buffer, priv->buffer_size,
 109                                  symbol_int_callback, priv, priv->bInterval);
 110                 result = usb_submit_urb(priv->int_urb, GFP_ATOMIC);
 111                 if (result)
 112                         dev_err(&port->dev,
 113                             "%s - failed resubmitting read urb, error %d\n",
 114                                                         __func__, result);
 115         } else
 116                 priv->actually_throttled = true;
 117         spin_unlock(&priv->lock);
 118 }
 119
 120 static int symbol_open(struct tty_struct *tty, struct usb_serial_port *port)
 121 {
 122         struct symbol_private *priv = usb_get_serial_data(port->serial);
 123         unsigned long flags;
 124         int result = 0;
 125
 126         spin_lock_irqsave(&priv->lock, flags);
 127         priv->throttled = false;
 128         priv->actually_throttled = false;
 129         priv->port = port;
 130         spin_unlock_irqrestore(&priv->lock, flags);
 131
 132         /* Start reading from the device */
 133         usb_fill_int_urb(priv->int_urb, priv->udev,
 134                          usb_rcvintpipe(priv->udev, priv->int_address),
 135                          priv->int_buffer, priv->buffer_size,
 136                          symbol_int_callback, priv, priv->bInterval);
 137         result = usb_submit_urb(priv->int_urb, GFP_KERNEL);
 138         if (result)
 139                 dev_err(&port->dev,
 140                         "%s - failed resubmitting read urb, error %d\n",
 141                         __func__, result);
 142         return result;
 143 }
 144
 145 static void symbol_close(struct usb_serial_port *port)
 146 {
 147         struct symbol_private *priv = usb_get_serial_data(port->serial);
 148
 149         /* shutdown our urbs */
 150         usb_kill_urb(priv->int_urb);
 151 }
 152
 153 static void symbol_throttle(struct tty_struct *tty)
 154 {
 155         struct usb_serial_port *port = tty->driver_data;
 156         struct symbol_private *priv = usb_get_serial_data(port->serial);
 157
 158         spin_lock_irq(&priv->lock);
 159         priv->throttled = true;
 160         spin_unlock_irq(&priv->lock);
 161 }
 162
 163 static void symbol_unthrottle(struct tty_struct *tty)
 164 {
 165         struct usb_serial_port *port = tty->driver_data;
 166         struct symbol_private *priv = usb_get_serial_data(port->serial);
 167         int result;
 168         bool was_throttled;
 169
 170         spin_lock_irq(&priv->lock);
 171         priv->throttled = false;
 172         was_throttled = priv->actually_throttled;
 173         priv->actually_throttled = false;
 174         spin_unlock_irq(&priv->lock);
 175
 176         if (was_throttled) {
 177                 result = usb_submit_urb(priv->int_urb, GFP_KERNEL);
 178                 if (result)
 179                         dev_err(&port->dev,
 180                                 "%s - failed submitting read urb, error %d\n",
 181                                                         __func__, result);
 182         }
 183 }
 184
 185 static int symbol_startup(struct usb_serial *serial)
 186 {
 187         struct symbol_private *priv;
 188         struct usb_host_interface *intf;
 189         int i;
 190         int retval = -ENOMEM;
 191         bool int_in_found = false;
 192
 193         /* create our private serial structure */
 194         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 195         if (priv == NULL) {
 196                 dev_err(&serial->dev->dev, "%s - Out of memory\n", __func__);
 197                 return -ENOMEM;
 198         }
 199         spin_lock_init(&priv->lock);
 200         priv->serial = serial;
 201         priv->port = serial->port[0];
 202         priv->udev = serial->dev;
 203
 204         /* find our interrupt endpoint */
 205         intf = serial->interface->altsetting;
 206         for (i = 0; i < intf->desc.bNumEndpoints; ++i) {
 207                 struct usb_endpoint_descriptor *endpoint;
 208
 209                 endpoint = &intf->endpoint[i].desc;
 210                 if (!usb_endpoint_is_int_in(endpoint))
 211                         continue;
 212
 213                 priv->int_urb = usb_alloc_urb(0, GFP_KERNEL);
 214                 if (!priv->int_urb) {
 215                         dev_err(&priv->udev->dev, "out of memory\n");
 216                         goto error;
 217                 }
 218
 219                 priv->buffer_size = usb_endpoint_maxp(endpoint) * 2;
 220                 priv->int_buffer = kmalloc(priv->buffer_size, GFP_KERNEL);
 221                 if (!priv->int_buffer) {
 222                         dev_err(&priv->udev->dev, "out of memory\n");
 223                         goto error;
 224                 }
 225
 226                 priv->int_address = endpoint->bEndpointAddress;
 227                 priv->bInterval = endpoint->bInterval;
 228
 229                 /* set up our int urb */
 230                 usb_fill_int_urb(priv->int_urb, priv->udev,
 231                                  usb_rcvintpipe(priv->udev,
 232                                                 endpoint->bEndpointAddress),
 233                                  priv->int_buffer, priv->buffer_size,
 234                                  symbol_int_callback, priv, priv->bInterval);
 235
 236                 int_in_found = true;
 237                 break;
 238                 }
 239
 240         if (!int_in_found) {
 241                 dev_err(&priv->udev->dev,
 242                         "Error - the proper endpoints were not found!\n");
 243                 goto error;
 244         }
 245
 246         usb_set_serial_data(serial, priv);
 247         return 0;
 248
 249 error:
 250         usb_free_urb(priv->int_urb);
 251         kfree(priv->int_buffer);
 252         kfree(priv);
 253         return retval;
 254 }
 255
 256 static void symbol_disconnect(struct usb_serial *serial)
 257 {
 258         struct symbol_private *priv = usb_get_serial_data(serial);
 259
 260         usb_kill_urb(priv->int_urb);
 261         usb_free_urb(priv->int_urb);
 262 }
 263
 264 static void symbol_release(struct usb_serial *serial)
 265 {
 266         struct symbol_private *priv = usb_get_serial_data(serial);
 267
 268         kfree(priv->int_buffer);
 269         kfree(priv);
 270 }
 271
 272 static struct usb_serial_driver symbol_device = {
 273         .driver = {
 274                 .owner =        THIS_MODULE,
 275                 .name =         "symbol",
 276         },
 277         .id_table =             id_table,
 278         .num_ports =            1,
 279         .attach =               symbol_startup,
 280         .open =                 symbol_open,
 281         .close =                symbol_close,
 282         .disconnect =           symbol_disconnect,
 283         .release =              symbol_release,
 284         .throttle =             symbol_throttle,
 285         .unthrottle =           symbol_unthrottle,
 286 };
 287
 288 static struct usb_serial_driver * const serial_drivers[] = {
 289         &symbol_device, NULL
 290 };
 291
 292 module_usb_serial_driver(serial_drivers, id_table);
 293
 294 MODULE_LICENSE("GPL");
 295
 296 module_param(debug, bool, S_IRUGO | S_IWUSR);
 297 MODULE_PARM_DESC(debug, "Debug enabled or not");