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         int result;
  52         int data_length;
  53
  54         switch (status) {
  55         case 0:
  56                 /* success */
  57                 break;
  58         case -ECONNRESET:
  59         case -ENOENT:
  60         case -ESHUTDOWN:
  61                 /* this urb is terminated, clean up */
  62                 dev_dbg(&port->dev, "%s - urb shutting down with status: %d\n",
  63                         __func__, status);
  64                 return;
  65         default:
  66                 dev_dbg(&port->dev, "%s - nonzero urb status received: %d\n",
  67                         __func__, status);
  68                 goto exit;
  69         }
  70
  71         usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
  72
  73         if (urb->actual_length > 1) {
  74                 data_length = urb->actual_length - 1;
  75
  76                 /*
  77                  * Data from the device comes with a 1 byte header:
  78                  *
  79                  * <size of data>data...
  80                  *      This is real data to be sent to the tty layer
  81                  * we pretty much just ignore the size and send everything
  82                  * else to the tty layer.
  83                  */
  84                 tty_insert_flip_string(&port->port, &data[1], data_length);
  85                 tty_flip_buffer_push(&port->port);
  86         } else {
  87                 dev_dbg(&priv->udev->dev,
  88                         "Improper amount of data received from the device, "
  89                         "%d bytes", urb->actual_length);
  90         }
  91
  92 exit:
  93         spin_lock(&priv->lock);
  94
  95         /* Continue trying to always read if we should */
  96         if (!priv->throttled) {
  97                 usb_fill_int_urb(priv->int_urb, priv->udev,
  98                                  usb_rcvintpipe(priv->udev,
  99                                                 priv->int_address),
 100                                  priv->int_buffer, priv->buffer_size,
 101                                  symbol_int_callback, priv, priv->bInterval);
 102                 result = usb_submit_urb(priv->int_urb, GFP_ATOMIC);
 103                 if (result)
 104                         dev_err(&port->dev,
 105                             "%s - failed resubmitting read urb, error %d\n",
 106                                                         __func__, result);
 107         } else
 108                 priv->actually_throttled = true;
 109         spin_unlock(&priv->lock);
 110 }
 111
 112 static int symbol_open(struct tty_struct *tty, struct usb_serial_port *port)
 113 {
 114         struct symbol_private *priv = usb_get_serial_data(port->serial);
 115         unsigned long flags;
 116         int result = 0;
 117
 118         spin_lock_irqsave(&priv->lock, flags);
 119         priv->throttled = false;
 120         priv->actually_throttled = false;
 121         priv->port = port;
 122         spin_unlock_irqrestore(&priv->lock, flags);
 123
 124         /* Start reading from the device */
 125         usb_fill_int_urb(priv->int_urb, priv->udev,
 126                          usb_rcvintpipe(priv->udev, priv->int_address),
 127                          priv->int_buffer, priv->buffer_size,
 128                          symbol_int_callback, priv, priv->bInterval);
 129         result = usb_submit_urb(priv->int_urb, GFP_KERNEL);
 130         if (result)
 131                 dev_err(&port->dev,
 132                         "%s - failed resubmitting read urb, error %d\n",
 133                         __func__, result);
 134         return result;
 135 }
 136
 137 static void symbol_close(struct usb_serial_port *port)
 138 {
 139         struct symbol_private *priv = usb_get_serial_data(port->serial);
 140
 141         /* shutdown our urbs */
 142         usb_kill_urb(priv->int_urb);
 143 }
 144
 145 static void symbol_throttle(struct tty_struct *tty)
 146 {
 147         struct usb_serial_port *port = tty->driver_data;
 148         struct symbol_private *priv = usb_get_serial_data(port->serial);
 149
 150         spin_lock_irq(&priv->lock);
 151         priv->throttled = true;
 152         spin_unlock_irq(&priv->lock);
 153 }
 154
 155 static void symbol_unthrottle(struct tty_struct *tty)
 156 {
 157         struct usb_serial_port *port = tty->driver_data;
 158         struct symbol_private *priv = usb_get_serial_data(port->serial);
 159         int result;
 160         bool was_throttled;
 161
 162         spin_lock_irq(&priv->lock);
 163         priv->throttled = false;
 164         was_throttled = priv->actually_throttled;
 165         priv->actually_throttled = false;
 166         spin_unlock_irq(&priv->lock);
 167
 168         if (was_throttled) {
 169                 result = usb_submit_urb(priv->int_urb, GFP_KERNEL);
 170                 if (result)
 171                         dev_err(&port->dev,
 172                                 "%s - failed submitting read urb, error %d\n",
 173                                                         __func__, result);
 174         }
 175 }
 176
 177 static int symbol_startup(struct usb_serial *serial)
 178 {
 179         struct symbol_private *priv;
 180         struct usb_host_interface *intf;
 181         int i;
 182         int retval = -ENOMEM;
 183         bool int_in_found = false;
 184
 185         /* create our private serial structure */
 186         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 187         if (priv == NULL) {
 188                 dev_err(&serial->dev->dev, "%s - Out of memory\n", __func__);
 189                 return -ENOMEM;
 190         }
 191         spin_lock_init(&priv->lock);
 192         priv->serial = serial;
 193         priv->port = serial->port[0];
 194         priv->udev = serial->dev;
 195
 196         /* find our interrupt endpoint */
 197         intf = serial->interface->altsetting;
 198         for (i = 0; i < intf->desc.bNumEndpoints; ++i) {
 199                 struct usb_endpoint_descriptor *endpoint;
 200
 201                 endpoint = &intf->endpoint[i].desc;
 202                 if (!usb_endpoint_is_int_in(endpoint))
 203                         continue;
 204
 205                 priv->int_urb = usb_alloc_urb(0, GFP_KERNEL);
 206                 if (!priv->int_urb) {
 207                         dev_err(&priv->udev->dev, "out of memory\n");
 208                         goto error;
 209                 }
 210
 211                 priv->buffer_size = usb_endpoint_maxp(endpoint) * 2;
 212                 priv->int_buffer = kmalloc(priv->buffer_size, GFP_KERNEL);
 213                 if (!priv->int_buffer) {
 214                         dev_err(&priv->udev->dev, "out of memory\n");
 215                         goto error;
 216                 }
 217
 218                 priv->int_address = endpoint->bEndpointAddress;
 219                 priv->bInterval = endpoint->bInterval;
 220
 221                 /* set up our int urb */
 222                 usb_fill_int_urb(priv->int_urb, priv->udev,
 223                                  usb_rcvintpipe(priv->udev,
 224                                                 endpoint->bEndpointAddress),
 225                                  priv->int_buffer, priv->buffer_size,
 226                                  symbol_int_callback, priv, priv->bInterval);
 227
 228                 int_in_found = true;
 229                 break;
 230                 }
 231
 232         if (!int_in_found) {
 233                 dev_err(&priv->udev->dev,
 234                         "Error - the proper endpoints were not found!\n");
 235                 goto error;
 236         }
 237
 238         usb_set_serial_data(serial, priv);
 239         return 0;
 240
 241 error:
 242         usb_free_urb(priv->int_urb);
 243         kfree(priv->int_buffer);
 244         kfree(priv);
 245         return retval;
 246 }
 247
 248 static void symbol_disconnect(struct usb_serial *serial)
 249 {
 250         struct symbol_private *priv = usb_get_serial_data(serial);
 251
 252         usb_kill_urb(priv->int_urb);
 253         usb_free_urb(priv->int_urb);
 254 }
 255
 256 static void symbol_release(struct usb_serial *serial)
 257 {
 258         struct symbol_private *priv = usb_get_serial_data(serial);
 259
 260         kfree(priv->int_buffer);
 261         kfree(priv);
 262 }
 263
 264 static struct usb_serial_driver symbol_device = {
 265         .driver = {
 266                 .owner =        THIS_MODULE,
 267                 .name =         "symbol",
 268         },
 269         .id_table =             id_table,
 270         .num_ports =            1,
 271         .attach =               symbol_startup,
 272         .open =                 symbol_open,
 273         .close =                symbol_close,
 274         .disconnect =           symbol_disconnect,
 275         .release =              symbol_release,
 276         .throttle =             symbol_throttle,
 277         .unthrottle =           symbol_unthrottle,
 278 };
 279
 280 static struct usb_serial_driver * const serial_drivers[] = {
 281         &symbol_device, NULL
 282 };
 283
 284 module_usb_serial_driver(serial_drivers, id_table);
 285
 286 MODULE_LICENSE("GPL");