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