drivers/usb/serial/opticon.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Opticon USB barcode to serial driver
   4  *
   5  * Copyright (C) 2011 - 2012 Johan Hovold <jhovold@gmail.com>
   6  * Copyright (C) 2011 Martin Jansen <martin.jansen@opticon.com>
   7  * Copyright (C) 2008 - 2009 Greg Kroah-Hartman <gregkh@suse.de>
   8  * Copyright (C) 2008 - 2009 Novell Inc.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/tty.h>
  13 #include <linux/tty_driver.h>
  14 #include <linux/slab.h>
  15 #include <linux/tty_flip.h>
  16 #include <linux/serial.h>
  17 #include <linux/module.h>
  18 #include <linux/usb.h>
  19 #include <linux/usb/serial.h>
  20 #include <linux/uaccess.h>
  21
  22 #define CONTROL_RTS                     0x02
  23 #define RESEND_CTS_STATE        0x03
  24
  25 /* max number of write urbs in flight */
  26 #define URB_UPPER_LIMIT 8
  27
  28 /* This driver works for the Opticon 1D barcode reader
  29  * an examples of 1D barcode types are EAN, UPC, Code39, IATA etc.. */
  30 #define DRIVER_DESC     "Opticon USB barcode to serial driver (1D)"
  31
  32 static const struct usb_device_id id_table[] = {
  33         { USB_DEVICE(0x065a, 0x0009) },
  34         { },
  35 };
  36 MODULE_DEVICE_TABLE(usb, id_table);
  37
  38 /* This structure holds all of the individual device information */
  39 struct opticon_private {
  40         spinlock_t lock;        /* protects the following flags */
  41         bool rts;
  42         bool cts;
  43         int outstanding_urbs;
  44         int outstanding_bytes;
  45
  46         struct usb_anchor anchor;
  47 };
  48
  49
  50 static void opticon_process_data_packet(struct usb_serial_port *port,
  51                                         const unsigned char *buf, size_t len)
  52 {
  53         tty_insert_flip_string(&port->port, buf, len);
  54         tty_flip_buffer_push(&port->port);
  55 }
  56
  57 static void opticon_process_status_packet(struct usb_serial_port *port,
  58                                         const unsigned char *buf, size_t len)
  59 {
  60         struct opticon_private *priv = usb_get_serial_port_data(port);
  61         unsigned long flags;
  62
  63         spin_lock_irqsave(&priv->lock, flags);
  64         if (buf[0] == 0x00)
  65                 priv->cts = false;
  66         else
  67                 priv->cts = true;
  68         spin_unlock_irqrestore(&priv->lock, flags);
  69 }
  70
  71 static void opticon_process_read_urb(struct urb *urb)
  72 {
  73         struct usb_serial_port *port = urb->context;
  74         const unsigned char *hdr = urb->transfer_buffer;
  75         const unsigned char *data = hdr + 2;
  76         size_t data_len = urb->actual_length - 2;
  77
  78         if (urb->actual_length <= 2) {
  79                 dev_dbg(&port->dev, "malformed packet received: %d bytes\n",
  80                                                         urb->actual_length);
  81                 return;
  82         }
  83         /*
  84          * Data from the device comes with a 2 byte header:
  85          *
  86          * <0x00><0x00>data...
  87          *      This is real data to be sent to the tty layer
  88          * <0x00><0x01>level
  89          *      This is a CTS level change, the third byte is the CTS
  90          *      value (0 for low, 1 for high).
  91          */
  92         if ((hdr[0] == 0x00) && (hdr[1] == 0x00)) {
  93                 opticon_process_data_packet(port, data, data_len);
  94         } else if ((hdr[0] == 0x00) && (hdr[1] == 0x01)) {
  95                 opticon_process_status_packet(port, data, data_len);
  96         } else {
  97                 dev_dbg(&port->dev, "unknown packet received: %02x %02x\n",
  98                                                         hdr[0], hdr[1]);
  99         }
 100 }
 101
 102 static int send_control_msg(struct usb_serial_port *port, u8 requesttype,
 103                                 u8 val)
 104 {
 105         struct usb_serial *serial = port->serial;
 106         int retval;
 107         u8 *buffer;
 108
 109         buffer = kzalloc(1, GFP_KERNEL);
 110         if (!buffer)
 111                 return -ENOMEM;
 112
 113         buffer[0] = val;
 114         /* Send the message to the vendor control endpoint
 115          * of the connected device */
 116         retval = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
 117                                 requesttype,
 118                                 USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
 119                                 0, 0, buffer, 1, USB_CTRL_SET_TIMEOUT);
 120         kfree(buffer);
 121
 122         if (retval < 0)
 123                 return retval;
 124
 125         return 0;
 126 }
 127
 128 static int opticon_open(struct tty_struct *tty, struct usb_serial_port *port)
 129 {
 130         struct opticon_private *priv = usb_get_serial_port_data(port);
 131         unsigned long flags;
 132         int res;
 133
 134         spin_lock_irqsave(&priv->lock, flags);
 135         priv->rts = false;
 136         spin_unlock_irqrestore(&priv->lock, flags);
 137
 138         /* Clear RTS line */
 139         send_control_msg(port, CONTROL_RTS, 0);
 140
 141         /* clear the halt status of the endpoint */
 142         usb_clear_halt(port->serial->dev, port->read_urb->pipe);
 143
 144         res = usb_serial_generic_open(tty, port);
 145         if (res)
 146                 return res;
 147
 148         /* Request CTS line state, sometimes during opening the current
 149          * CTS state can be missed. */
 150         send_control_msg(port, RESEND_CTS_STATE, 1);
 151
 152         return res;
 153 }
 154
 155 static void opticon_close(struct usb_serial_port *port)
 156 {
 157         struct opticon_private *priv = usb_get_serial_port_data(port);
 158
 159         usb_kill_anchored_urbs(&priv->anchor);
 160
 161         usb_serial_generic_close(port);
 162 }
 163
 164 static void opticon_write_control_callback(struct urb *urb)
 165 {
 166         struct usb_serial_port *port = urb->context;
 167         struct opticon_private *priv = usb_get_serial_port_data(port);
 168         int status = urb->status;
 169         unsigned long flags;
 170
 171         /* free up the transfer buffer, as usb_free_urb() does not do this */
 172         kfree(urb->transfer_buffer);
 173
 174         /* setup packet may be set if we're using it for writing */
 175         kfree(urb->setup_packet);
 176
 177         if (status)
 178                 dev_dbg(&port->dev,
 179                         "%s - non-zero urb status received: %d\n",
 180                         __func__, status);
 181
 182         spin_lock_irqsave(&priv->lock, flags);
 183         --priv->outstanding_urbs;
 184         priv->outstanding_bytes -= urb->transfer_buffer_length;
 185         spin_unlock_irqrestore(&priv->lock, flags);
 186
 187         usb_serial_port_softint(port);
 188 }
 189
 190 static int opticon_write(struct tty_struct *tty, struct usb_serial_port *port,
 191                          const unsigned char *buf, int count)
 192 {
 193         struct opticon_private *priv = usb_get_serial_port_data(port);
 194         struct usb_serial *serial = port->serial;
 195         struct urb *urb;
 196         unsigned char *buffer;
 197         unsigned long flags;
 198         struct usb_ctrlrequest *dr;
 199         int ret = -ENOMEM;
 200
 201         spin_lock_irqsave(&priv->lock, flags);
 202         if (priv->outstanding_urbs > URB_UPPER_LIMIT) {
 203                 spin_unlock_irqrestore(&priv->lock, flags);
 204                 dev_dbg(&port->dev, "%s - write limit hit\n", __func__);
 205                 return 0;
 206         }
 207         priv->outstanding_urbs++;
 208         priv->outstanding_bytes += count;
 209         spin_unlock_irqrestore(&priv->lock, flags);
 210
 211         buffer = kmemdup(buf, count, GFP_ATOMIC);
 212         if (!buffer)
 213                 goto error_no_buffer;
 214
 215         urb = usb_alloc_urb(0, GFP_ATOMIC);
 216         if (!urb)
 217                 goto error_no_urb;
 218
 219         usb_serial_debug_data(&port->dev, __func__, count, buffer);
 220
 221         /* The connected devices do not have a bulk write endpoint,
 222          * to transmit data to de barcode device the control endpoint is used */
 223         dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
 224         if (!dr)
 225                 goto error_no_dr;
 226
 227         dr->bRequestType = USB_TYPE_VENDOR | USB_RECIP_INTERFACE | USB_DIR_OUT;
 228         dr->bRequest = 0x01;
 229         dr->wValue = 0;
 230         dr->wIndex = 0;
 231         dr->wLength = cpu_to_le16(count);
 232
 233         usb_fill_control_urb(urb, serial->dev,
 234                 usb_sndctrlpipe(serial->dev, 0),
 235                 (unsigned char *)dr, buffer, count,
 236                 opticon_write_control_callback, port);
 237
 238         usb_anchor_urb(urb, &priv->anchor);
 239
 240         /* send it down the pipe */
 241         ret = usb_submit_urb(urb, GFP_ATOMIC);
 242         if (ret) {
 243                 dev_err(&port->dev, "failed to submit write urb: %d\n", ret);
 244                 usb_unanchor_urb(urb);
 245                 goto error;
 246         }
 247
 248         /* we are done with this urb, so let the host driver
 249          * really free it when it is finished with it */
 250         usb_free_urb(urb);
 251
 252         return count;
 253 error:
 254         kfree(dr);
 255 error_no_dr:
 256         usb_free_urb(urb);
 257 error_no_urb:
 258         kfree(buffer);
 259 error_no_buffer:
 260         spin_lock_irqsave(&priv->lock, flags);
 261         --priv->outstanding_urbs;
 262         priv->outstanding_bytes -= count;
 263         spin_unlock_irqrestore(&priv->lock, flags);
 264
 265         return ret;
 266 }
 267
 268 static unsigned int opticon_write_room(struct tty_struct *tty)
 269 {
 270         struct usb_serial_port *port = tty->driver_data;
 271         struct opticon_private *priv = usb_get_serial_port_data(port);
 272         unsigned long flags;
 273
 274         /*
 275          * We really can take almost anything the user throws at us
 276          * but let's pick a nice big number to tell the tty
 277          * layer that we have lots of free space, unless we don't.
 278          */
 279         spin_lock_irqsave(&priv->lock, flags);
 280         if (priv->outstanding_urbs > URB_UPPER_LIMIT * 2 / 3) {
 281                 spin_unlock_irqrestore(&priv->lock, flags);
 282                 dev_dbg(&port->dev, "%s - write limit hit\n", __func__);
 283                 return 0;
 284         }
 285         spin_unlock_irqrestore(&priv->lock, flags);
 286
 287         return 2048;
 288 }
 289
 290 static unsigned int opticon_chars_in_buffer(struct tty_struct *tty)
 291 {
 292         struct usb_serial_port *port = tty->driver_data;
 293         struct opticon_private *priv = usb_get_serial_port_data(port);
 294         unsigned long flags;
 295         unsigned int count;
 296
 297         spin_lock_irqsave(&priv->lock, flags);
 298         count = priv->outstanding_bytes;
 299         spin_unlock_irqrestore(&priv->lock, flags);
 300
 301         return count;
 302 }
 303
 304 static int opticon_tiocmget(struct tty_struct *tty)
 305 {
 306         struct usb_serial_port *port = tty->driver_data;
 307         struct opticon_private *priv = usb_get_serial_port_data(port);
 308         unsigned long flags;
 309         int result = 0;
 310
 311         spin_lock_irqsave(&priv->lock, flags);
 312         if (priv->rts)
 313                 result |= TIOCM_RTS;
 314         if (priv->cts)
 315                 result |= TIOCM_CTS;
 316         spin_unlock_irqrestore(&priv->lock, flags);
 317
 318         dev_dbg(&port->dev, "%s - %x\n", __func__, result);
 319         return result;
 320 }
 321
 322 static int opticon_tiocmset(struct tty_struct *tty,
 323                            unsigned int set, unsigned int clear)
 324 {
 325         struct usb_serial_port *port = tty->driver_data;
 326         struct opticon_private *priv = usb_get_serial_port_data(port);
 327         unsigned long flags;
 328         bool rts;
 329         bool changed = false;
 330         int ret;
 331
 332         /* We only support RTS so we only handle that */
 333         spin_lock_irqsave(&priv->lock, flags);
 334
 335         rts = priv->rts;
 336         if (set & TIOCM_RTS)
 337                 priv->rts = true;
 338         if (clear & TIOCM_RTS)
 339                 priv->rts = false;
 340         changed = rts ^ priv->rts;
 341         spin_unlock_irqrestore(&priv->lock, flags);
 342
 343         if (!changed)
 344                 return 0;
 345
 346         ret = send_control_msg(port, CONTROL_RTS, !rts);
 347         if (ret)
 348                 return usb_translate_errors(ret);
 349
 350         return 0;
 351 }
 352
 353 static int opticon_port_probe(struct usb_serial_port *port)
 354 {
 355         struct opticon_private *priv;
 356
 357         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 358         if (!priv)
 359                 return -ENOMEM;
 360
 361         spin_lock_init(&priv->lock);
 362         init_usb_anchor(&priv->anchor);
 363
 364         usb_set_serial_port_data(port, priv);
 365
 366         return 0;
 367 }
 368
 369 static void opticon_port_remove(struct usb_serial_port *port)
 370 {
 371         struct opticon_private *priv = usb_get_serial_port_data(port);
 372
 373         kfree(priv);
 374 }
 375
 376 static struct usb_serial_driver opticon_device = {
 377         .driver = {
 378                 .owner =        THIS_MODULE,
 379                 .name =         "opticon",
 380         },
 381         .id_table =             id_table,
 382         .num_ports =            1,
 383         .num_bulk_in =          1,
 384         .bulk_in_size =         256,
 385         .port_probe =           opticon_port_probe,
 386         .port_remove =          opticon_port_remove,
 387         .open =                 opticon_open,
 388         .close =                opticon_close,
 389         .write =                opticon_write,
 390         .write_room =           opticon_write_room,
 391         .chars_in_buffer =      opticon_chars_in_buffer,
 392         .throttle =             usb_serial_generic_throttle,
 393         .unthrottle =           usb_serial_generic_unthrottle,
 394         .tiocmget =             opticon_tiocmget,
 395         .tiocmset =             opticon_tiocmset,
 396         .process_read_urb =     opticon_process_read_urb,
 397 };
 398
 399 static struct usb_serial_driver * const serial_drivers[] = {
 400         &opticon_device, NULL
 401 };
 402
 403 module_usb_serial_driver(serial_drivers, id_table);
 404
 405 MODULE_DESCRIPTION(DRIVER_DESC);
 406 MODULE_LICENSE("GPL v2");