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