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