linux/drivers/usb/serial/cypress_m8.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * USB Cypress M8 driver
   4 *
   5 *      Copyright (C) 2004
   6 *          Lonnie Mendez (dignome@gmail.com)
   7 *      Copyright (C) 2003,2004
   8 *          Neil Whelchel (koyama@firstlight.net)
   9 *
  10 * See Documentation/usb/usb-serial.rst for more information on using this
  11 * driver
  12 *
  13 * See http://geocities.com/i0xox0i for information on this driver and the
  14 * earthmate usb device.
  15 */
  16
  17/* Thanks to Neil Whelchel for writing the first cypress m8 implementation
  18   for linux. */
  19/* Thanks to cypress for providing references for the hid reports. */
  20/* Thanks to Jiang Zhang for providing links and for general help. */
  21/* Code originates and was built up from ftdi_sio, belkin, pl2303 and others.*/
  22
  23
  24#include <linux/kernel.h>
  25#include <linux/errno.h>
  26#include <linux/slab.h>
  27#include <linux/tty.h>
  28#include <linux/tty_driver.h>
  29#include <linux/tty_flip.h>
  30#include <linux/module.h>
  31#include <linux/moduleparam.h>
  32#include <linux/spinlock.h>
  33#include <linux/usb.h>
  34#include <linux/usb/serial.h>
  35#include <linux/serial.h>
  36#include <linux/kfifo.h>
  37#include <linux/delay.h>
  38#include <linux/uaccess.h>
  39#include <asm/unaligned.h>
  40
  41#include "cypress_m8.h"
  42
  43
  44static bool stats;
  45static int interval;
  46static bool unstable_bauds;
  47
  48#define DRIVER_AUTHOR "Lonnie Mendez <dignome@gmail.com>, Neil Whelchel <koyama@firstlight.net>"
  49#define DRIVER_DESC "Cypress USB to Serial Driver"
  50
  51/* write buffer size defines */
  52#define CYPRESS_BUF_SIZE        1024
  53
  54static const struct usb_device_id id_table_earthmate[] = {
  55        { USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
  56        { USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
  57        { }                                             /* Terminating entry */
  58};
  59
  60static const struct usb_device_id id_table_cyphidcomrs232[] = {
  61        { USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
  62        { USB_DEVICE(VENDOR_ID_SAI, PRODUCT_ID_CYPHIDCOM) },
  63        { USB_DEVICE(VENDOR_ID_POWERCOM, PRODUCT_ID_UPS) },
  64        { USB_DEVICE(VENDOR_ID_FRWD, PRODUCT_ID_CYPHIDCOM_FRWD) },
  65        { }                                             /* Terminating entry */
  66};
  67
  68static const struct usb_device_id id_table_nokiaca42v2[] = {
  69        { USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
  70        { }                                             /* Terminating entry */
  71};
  72
  73static const struct usb_device_id id_table_combined[] = {
  74        { USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
  75        { USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
  76        { USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
  77        { USB_DEVICE(VENDOR_ID_SAI, PRODUCT_ID_CYPHIDCOM) },
  78        { USB_DEVICE(VENDOR_ID_POWERCOM, PRODUCT_ID_UPS) },
  79        { USB_DEVICE(VENDOR_ID_FRWD, PRODUCT_ID_CYPHIDCOM_FRWD) },
  80        { USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
  81        { }                                             /* Terminating entry */
  82};
  83
  84MODULE_DEVICE_TABLE(usb, id_table_combined);
  85
  86enum packet_format {
  87        packet_format_1,  /* b0:status, b1:payload count */
  88        packet_format_2   /* b0[7:3]:status, b0[2:0]:payload count */
  89};
  90
  91struct cypress_private {
  92        spinlock_t lock;                   /* private lock */
  93        int chiptype;                      /* identifier of device, for quirks/etc */
  94        int bytes_in;                      /* used for statistics */
  95        int bytes_out;                     /* used for statistics */
  96        int cmd_count;                     /* used for statistics */
  97        int cmd_ctrl;                      /* always set this to 1 before issuing a command */
  98        struct kfifo write_fifo;           /* write fifo */
  99        int write_urb_in_use;              /* write urb in use indicator */
 100        int write_urb_interval;            /* interval to use for write urb */
 101        int read_urb_interval;             /* interval to use for read urb */
 102        int comm_is_ok;                    /* true if communication is (still) ok */
 103        __u8 line_control;                 /* holds dtr / rts value */
 104        __u8 current_status;               /* received from last read - info on dsr,cts,cd,ri,etc */
 105        __u8 current_config;               /* stores the current configuration byte */
 106        __u8 rx_flags;                     /* throttling - used from whiteheat/ftdi_sio */
 107        enum packet_format pkt_fmt;        /* format to use for packet send / receive */
 108        int get_cfg_unsafe;                /* If true, the CYPRESS_GET_CONFIG is unsafe */
 109        int baud_rate;                     /* stores current baud rate in
 110                                              integer form */
 111        char prev_status;                  /* used for TIOCMIWAIT */
 112};
 113
 114/* function prototypes for the Cypress USB to serial device */
 115static int  cypress_earthmate_port_probe(struct usb_serial_port *port);
 116static int  cypress_hidcom_port_probe(struct usb_serial_port *port);
 117static int  cypress_ca42v2_port_probe(struct usb_serial_port *port);
 118static void cypress_port_remove(struct usb_serial_port *port);
 119static int  cypress_open(struct tty_struct *tty, struct usb_serial_port *port);
 120static void cypress_close(struct usb_serial_port *port);
 121static void cypress_dtr_rts(struct usb_serial_port *port, int on);
 122static int  cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
 123                        const unsigned char *buf, int count);
 124static void cypress_send(struct usb_serial_port *port);
 125static unsigned int cypress_write_room(struct tty_struct *tty);
 126static void cypress_earthmate_init_termios(struct tty_struct *tty);
 127static void cypress_set_termios(struct tty_struct *tty,
 128                        struct usb_serial_port *port, struct ktermios *old);
 129static int  cypress_tiocmget(struct tty_struct *tty);
 130static int  cypress_tiocmset(struct tty_struct *tty,
 131                        unsigned int set, unsigned int clear);
 132static unsigned int cypress_chars_in_buffer(struct tty_struct *tty);
 133static void cypress_throttle(struct tty_struct *tty);
 134static void cypress_unthrottle(struct tty_struct *tty);
 135static void cypress_set_dead(struct usb_serial_port *port);
 136static void cypress_read_int_callback(struct urb *urb);
 137static void cypress_write_int_callback(struct urb *urb);
 138
 139static struct usb_serial_driver cypress_earthmate_device = {
 140        .driver = {
 141                .owner =                THIS_MODULE,
 142                .name =                 "earthmate",
 143        },
 144        .description =                  "DeLorme Earthmate USB",
 145        .id_table =                     id_table_earthmate,
 146        .num_ports =                    1,
 147        .port_probe =                   cypress_earthmate_port_probe,
 148        .port_remove =                  cypress_port_remove,
 149        .open =                         cypress_open,
 150        .close =                        cypress_close,
 151        .dtr_rts =                      cypress_dtr_rts,
 152        .write =                        cypress_write,
 153        .write_room =                   cypress_write_room,
 154        .init_termios =                 cypress_earthmate_init_termios,
 155        .set_termios =                  cypress_set_termios,
 156        .tiocmget =                     cypress_tiocmget,
 157        .tiocmset =                     cypress_tiocmset,
 158        .tiocmiwait =                   usb_serial_generic_tiocmiwait,
 159        .chars_in_buffer =              cypress_chars_in_buffer,
 160        .throttle =                     cypress_throttle,
 161        .unthrottle =                   cypress_unthrottle,
 162        .read_int_callback =            cypress_read_int_callback,
 163        .write_int_callback =           cypress_write_int_callback,
 164};
 165
 166static struct usb_serial_driver cypress_hidcom_device = {
 167        .driver = {
 168                .owner =                THIS_MODULE,
 169                .name =                 "cyphidcom",
 170        },
 171        .description =                  "HID->COM RS232 Adapter",
 172        .id_table =                     id_table_cyphidcomrs232,
 173        .num_ports =                    1,
 174        .port_probe =                   cypress_hidcom_port_probe,
 175        .port_remove =                  cypress_port_remove,
 176        .open =                         cypress_open,
 177        .close =                        cypress_close,
 178        .dtr_rts =                      cypress_dtr_rts,
 179        .write =                        cypress_write,
 180        .write_room =                   cypress_write_room,
 181        .set_termios =                  cypress_set_termios,
 182        .tiocmget =                     cypress_tiocmget,
 183        .tiocmset =                     cypress_tiocmset,
 184        .tiocmiwait =                   usb_serial_generic_tiocmiwait,
 185        .chars_in_buffer =              cypress_chars_in_buffer,
 186        .throttle =                     cypress_throttle,
 187        .unthrottle =                   cypress_unthrottle,
 188        .read_int_callback =            cypress_read_int_callback,
 189        .write_int_callback =           cypress_write_int_callback,
 190};
 191
 192static struct usb_serial_driver cypress_ca42v2_device = {
 193        .driver = {
 194                .owner =                THIS_MODULE,
 195                .name =                 "nokiaca42v2",
 196        },
 197        .description =                  "Nokia CA-42 V2 Adapter",
 198        .id_table =                     id_table_nokiaca42v2,
 199        .num_ports =                    1,
 200        .port_probe =                   cypress_ca42v2_port_probe,
 201        .port_remove =                  cypress_port_remove,
 202        .open =                         cypress_open,
 203        .close =                        cypress_close,
 204        .dtr_rts =                      cypress_dtr_rts,
 205        .write =                        cypress_write,
 206        .write_room =                   cypress_write_room,
 207        .set_termios =                  cypress_set_termios,
 208        .tiocmget =                     cypress_tiocmget,
 209        .tiocmset =                     cypress_tiocmset,
 210        .tiocmiwait =                   usb_serial_generic_tiocmiwait,
 211        .chars_in_buffer =              cypress_chars_in_buffer,
 212        .throttle =                     cypress_throttle,
 213        .unthrottle =                   cypress_unthrottle,
 214        .read_int_callback =            cypress_read_int_callback,
 215        .write_int_callback =           cypress_write_int_callback,
 216};
 217
 218static struct usb_serial_driver * const serial_drivers[] = {
 219        &cypress_earthmate_device, &cypress_hidcom_device,
 220        &cypress_ca42v2_device, NULL
 221};
 222
 223/*****************************************************************************
 224 * Cypress serial helper functions
 225 *****************************************************************************/
 226
 227/* FRWD Dongle hidcom needs to skip reset and speed checks */
 228static inline bool is_frwd(struct usb_device *dev)
 229{
 230        return ((le16_to_cpu(dev->descriptor.idVendor) == VENDOR_ID_FRWD) &&
 231                (le16_to_cpu(dev->descriptor.idProduct) == PRODUCT_ID_CYPHIDCOM_FRWD));
 232}
 233
 234static int analyze_baud_rate(struct usb_serial_port *port, speed_t new_rate)
 235{
 236        struct cypress_private *priv;
 237        priv = usb_get_serial_port_data(port);
 238
 239        if (unstable_bauds)
 240                return new_rate;
 241
 242        /* FRWD Dongle uses 115200 bps */
 243        if (is_frwd(port->serial->dev))
 244                return new_rate;
 245
 246        /*
 247         * The general purpose firmware for the Cypress M8 allows for
 248         * a maximum speed of 57600bps (I have no idea whether DeLorme
 249         * chose to use the general purpose firmware or not), if you
 250         * need to modify this speed setting for your own project
 251         * please add your own chiptype and modify the code likewise.
 252         * The Cypress HID->COM device will work successfully up to
 253         * 115200bps (but the actual throughput is around 3kBps).
 254         */
 255        if (port->serial->dev->speed == USB_SPEED_LOW) {
 256                /*
 257                 * Mike Isely <isely@pobox.com> 2-Feb-2008: The
 258                 * Cypress app note that describes this mechanism
 259                 * states the the low-speed part can't handle more
 260                 * than 800 bytes/sec, in which case 4800 baud is the
 261                 * safest speed for a part like that.
 262                 */
 263                if (new_rate > 4800) {
 264                        dev_dbg(&port->dev,
 265                                "%s - failed setting baud rate, device incapable speed %d\n",
 266                                __func__, new_rate);
 267                        return -1;
 268                }
 269        }
 270        switch (priv->chiptype) {
 271        case CT_EARTHMATE:
 272                if (new_rate <= 600) {
 273                        /* 300 and 600 baud rates are supported under
 274                         * the generic firmware, but are not used with
 275                         * NMEA and SiRF protocols */
 276                        dev_dbg(&port->dev,
 277                                "%s - failed setting baud rate, unsupported speed of %d on Earthmate GPS\n",
 278                                __func__, new_rate);
 279                        return -1;
 280                }
 281                break;
 282        default:
 283                break;
 284        }
 285        return new_rate;
 286}
 287
 288
 289/* This function can either set or retrieve the current serial line settings */
 290static int cypress_serial_control(struct tty_struct *tty,
 291        struct usb_serial_port *port, speed_t baud_rate, int data_bits,
 292        int stop_bits, int parity_enable, int parity_type, int reset,
 293        int cypress_request_type)
 294{
 295        int new_baudrate = 0, retval = 0, tries = 0;
 296        struct cypress_private *priv;
 297        struct device *dev = &port->dev;
 298        u8 *feature_buffer;
 299        const unsigned int feature_len = 5;
 300        unsigned long flags;
 301
 302        priv = usb_get_serial_port_data(port);
 303
 304        if (!priv->comm_is_ok)
 305                return -ENODEV;
 306
 307        feature_buffer = kcalloc(feature_len, sizeof(u8), GFP_KERNEL);
 308        if (!feature_buffer)
 309                return -ENOMEM;
 310
 311        switch (cypress_request_type) {
 312        case CYPRESS_SET_CONFIG:
 313                /* 0 means 'Hang up' so doesn't change the true bit rate */
 314                new_baudrate = priv->baud_rate;
 315                if (baud_rate && baud_rate != priv->baud_rate) {
 316                        dev_dbg(dev, "%s - baud rate is changing\n", __func__);
 317                        retval = analyze_baud_rate(port, baud_rate);
 318                        if (retval >= 0) {
 319                                new_baudrate = retval;
 320                                dev_dbg(dev, "%s - New baud rate set to %d\n",
 321                                        __func__, new_baudrate);
 322                        }
 323                }
 324                dev_dbg(dev, "%s - baud rate is being sent as %d\n", __func__,
 325                        new_baudrate);
 326
 327                /* fill the feature_buffer with new configuration */
 328                put_unaligned_le32(new_baudrate, feature_buffer);
 329                feature_buffer[4] |= data_bits - 5;   /* assign data bits in 2 bit space ( max 3 ) */
 330                /* 1 bit gap */
 331                feature_buffer[4] |= (stop_bits << 3);   /* assign stop bits in 1 bit space */
 332                feature_buffer[4] |= (parity_enable << 4);   /* assign parity flag in 1 bit space */
 333                feature_buffer[4] |= (parity_type << 5);   /* assign parity type in 1 bit space */
 334                /* 1 bit gap */
 335                feature_buffer[4] |= (reset << 7);   /* assign reset at end of byte, 1 bit space */
 336
 337                dev_dbg(dev, "%s - device is being sent this feature report:\n", __func__);
 338                dev_dbg(dev, "%s - %02X - %02X - %02X - %02X - %02X\n", __func__,
 339                        feature_buffer[0], feature_buffer[1],
 340                        feature_buffer[2], feature_buffer[3],
 341                        feature_buffer[4]);
 342
 343                do {
 344                        retval = usb_control_msg(port->serial->dev,
 345                                        usb_sndctrlpipe(port->serial->dev, 0),
 346                                        HID_REQ_SET_REPORT,
 347                                        USB_DIR_OUT | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
 348                                        0x0300, 0, feature_buffer,
 349                                        feature_len, 500);
 350
 351                        if (tries++ >= 3)
 352                                break;
 353
 354                } while (retval != feature_len &&
 355                         retval != -ENODEV);
 356
 357                if (retval != feature_len) {
 358                        dev_err(dev, "%s - failed sending serial line settings - %d\n",
 359                                __func__, retval);
 360                        cypress_set_dead(port);
 361                } else {
 362                        spin_lock_irqsave(&priv->lock, flags);
 363                        priv->baud_rate = new_baudrate;
 364                        priv->current_config = feature_buffer[4];
 365                        spin_unlock_irqrestore(&priv->lock, flags);
 366                        /* If we asked for a speed change encode it */
 367                        if (baud_rate)
 368                                tty_encode_baud_rate(tty,
 369                                        new_baudrate, new_baudrate);
 370                }
 371        break;
 372        case CYPRESS_GET_CONFIG:
 373                if (priv->get_cfg_unsafe) {
 374                        /* Not implemented for this device,
 375                           and if we try to do it we're likely
 376                           to crash the hardware. */
 377                        retval = -ENOTTY;
 378                        goto out;
 379                }
 380                dev_dbg(dev, "%s - retrieving serial line settings\n", __func__);
 381                do {
 382                        retval = usb_control_msg(port->serial->dev,
 383                                        usb_rcvctrlpipe(port->serial->dev, 0),
 384                                        HID_REQ_GET_REPORT,
 385                                        USB_DIR_IN | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
 386                                        0x0300, 0, feature_buffer,
 387                                        feature_len, 500);
 388
 389                        if (tries++ >= 3)
 390                                break;
 391                } while (retval != feature_len
 392                                                && retval != -ENODEV);
 393
 394                if (retval != feature_len) {
 395                        dev_err(dev, "%s - failed to retrieve serial line settings - %d\n",
 396                                __func__, retval);
 397                        cypress_set_dead(port);
 398                        goto out;
 399                } else {
 400                        spin_lock_irqsave(&priv->lock, flags);
 401                        /* store the config in one byte, and later
 402                           use bit masks to check values */
 403                        priv->current_config = feature_buffer[4];
 404                        priv->baud_rate = get_unaligned_le32(feature_buffer);
 405                        spin_unlock_irqrestore(&priv->lock, flags);
 406                }
 407        }
 408        spin_lock_irqsave(&priv->lock, flags);
 409        ++priv->cmd_count;
 410        spin_unlock_irqrestore(&priv->lock, flags);
 411out:
 412        kfree(feature_buffer);
 413        return retval;
 414} /* cypress_serial_control */
 415
 416
 417static void cypress_set_dead(struct usb_serial_port *port)
 418{
 419        struct cypress_private *priv = usb_get_serial_port_data(port);
 420        unsigned long flags;
 421
 422        spin_lock_irqsave(&priv->lock, flags);
 423        if (!priv->comm_is_ok) {
 424                spin_unlock_irqrestore(&priv->lock, flags);
 425                return;
 426        }
 427        priv->comm_is_ok = 0;
 428        spin_unlock_irqrestore(&priv->lock, flags);
 429
 430        dev_err(&port->dev, "cypress_m8 suspending failing port %d - "
 431                "interval might be too short\n", port->port_number);
 432}
 433
 434
 435/*****************************************************************************
 436 * Cypress serial driver functions
 437 *****************************************************************************/
 438
 439
 440static int cypress_generic_port_probe(struct usb_serial_port *port)
 441{
 442        struct usb_serial *serial = port->serial;
 443        struct cypress_private *priv;
 444
 445        if (!port->interrupt_out_urb || !port->interrupt_in_urb) {
 446                dev_err(&port->dev, "required endpoint is missing\n");
 447                return -ENODEV;
 448        }
 449
 450        priv = kzalloc(sizeof(struct cypress_private), GFP_KERNEL);
 451        if (!priv)
 452                return -ENOMEM;
 453
 454        priv->comm_is_ok = !0;
 455        spin_lock_init(&priv->lock);
 456        if (kfifo_alloc(&priv->write_fifo, CYPRESS_BUF_SIZE, GFP_KERNEL)) {
 457                kfree(priv);
 458                return -ENOMEM;
 459        }
 460
 461        /* Skip reset for FRWD device. It is a workaound:
 462           device hangs if it receives SET_CONFIGURE in Configured
 463           state. */
 464        if (!is_frwd(serial->dev))
 465                usb_reset_configuration(serial->dev);
 466
 467        priv->cmd_ctrl = 0;
 468        priv->line_control = 0;
 469        priv->rx_flags = 0;
 470        /* Default packet format setting is determined by packet size.
 471           Anything with a size larger then 9 must have a separate
 472           count field since the 3 bit count field is otherwise too
 473           small.  Otherwise we can use the slightly more compact
 474           format.  This is in accordance with the cypress_m8 serial
 475           converter app note. */
 476        if (port->interrupt_out_size > 9)
 477                priv->pkt_fmt = packet_format_1;
 478        else
 479                priv->pkt_fmt = packet_format_2;
 480
 481        if (interval > 0) {
 482                priv->write_urb_interval = interval;
 483                priv->read_urb_interval = interval;
 484                dev_dbg(&port->dev, "%s - read & write intervals forced to %d\n",
 485                        __func__, interval);
 486        } else {
 487                priv->write_urb_interval = port->interrupt_out_urb->interval;
 488                priv->read_urb_interval = port->interrupt_in_urb->interval;
 489                dev_dbg(&port->dev, "%s - intervals: read=%d write=%d\n",
 490                        __func__, priv->read_urb_interval,
 491                        priv->write_urb_interval);
 492        }
 493        usb_set_serial_port_data(port, priv);
 494
 495        port->port.drain_delay = 256;
 496
 497        return 0;
 498}
 499
 500
 501static int cypress_earthmate_port_probe(struct usb_serial_port *port)
 502{
 503        struct usb_serial *serial = port->serial;
 504        struct cypress_private *priv;
 505        int ret;
 506
 507        ret = cypress_generic_port_probe(port);
 508        if (ret) {
 509                dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
 510                return ret;
 511        }
 512
 513        priv = usb_get_serial_port_data(port);
 514        priv->chiptype = CT_EARTHMATE;
 515        /* All Earthmate devices use the separated-count packet
 516           format!  Idiotic. */
 517        priv->pkt_fmt = packet_format_1;
 518        if (serial->dev->descriptor.idProduct !=
 519                                cpu_to_le16(PRODUCT_ID_EARTHMATEUSB)) {
 520                /* The old original USB Earthmate seemed able to
 521                   handle GET_CONFIG requests; everything they've
 522                   produced since that time crashes if this command is
 523                   attempted :-( */
 524                dev_dbg(&port->dev,
 525                        "%s - Marking this device as unsafe for GET_CONFIG commands\n",
 526                        __func__);
 527                priv->get_cfg_unsafe = !0;
 528        }
 529
 530        return 0;
 531}
 532
 533static int cypress_hidcom_port_probe(struct usb_serial_port *port)
 534{
 535        struct cypress_private *priv;
 536        int ret;
 537
 538        ret = cypress_generic_port_probe(port);
 539        if (ret) {
 540                dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
 541                return ret;
 542        }
 543
 544        priv = usb_get_serial_port_data(port);
 545        priv->chiptype = CT_CYPHIDCOM;
 546
 547        return 0;
 548}
 549
 550static int cypress_ca42v2_port_probe(struct usb_serial_port *port)
 551{
 552        struct cypress_private *priv;
 553        int ret;
 554
 555        ret = cypress_generic_port_probe(port);
 556        if (ret) {
 557                dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
 558                return ret;
 559        }
 560
 561        priv = usb_get_serial_port_data(port);
 562        priv->chiptype = CT_CA42V2;
 563
 564        return 0;
 565}
 566
 567static void cypress_port_remove(struct usb_serial_port *port)
 568{
 569        struct cypress_private *priv;
 570
 571        priv = usb_get_serial_port_data(port);
 572
 573        kfifo_free(&priv->write_fifo);
 574        kfree(priv);
 575}
 576
 577static int cypress_open(struct tty_struct *tty, struct usb_serial_port *port)
 578{
 579        struct cypress_private *priv = usb_get_serial_port_data(port);
 580        struct usb_serial *serial = port->serial;
 581        unsigned long flags;
 582        int result = 0;
 583
 584        if (!priv->comm_is_ok)
 585                return -EIO;
 586
 587        /* clear halts before open */
 588        usb_clear_halt(serial->dev, 0x81);
 589        usb_clear_halt(serial->dev, 0x02);
 590
 591        spin_lock_irqsave(&priv->lock, flags);
 592        /* reset read/write statistics */
 593        priv->bytes_in = 0;
 594        priv->bytes_out = 0;
 595        priv->cmd_count = 0;
 596        priv->rx_flags = 0;
 597        spin_unlock_irqrestore(&priv->lock, flags);
 598
 599        /* Set termios */
 600        cypress_send(port);
 601
 602        if (tty)
 603                cypress_set_termios(tty, port, NULL);
 604
 605        /* setup the port and start reading from the device */
 606        usb_fill_int_urb(port->interrupt_in_urb, serial->dev,
 607                usb_rcvintpipe(serial->dev, port->interrupt_in_endpointAddress),
 608                port->interrupt_in_urb->transfer_buffer,
 609                port->interrupt_in_urb->transfer_buffer_length,
 610                cypress_read_int_callback, port, priv->read_urb_interval);
 611        result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
 612
 613        if (result) {
 614                dev_err(&port->dev,
 615                        "%s - failed submitting read urb, error %d\n",
 616                                                        __func__, result);
 617                cypress_set_dead(port);
 618        }
 619
 620        return result;
 621} /* cypress_open */
 622
 623static void cypress_dtr_rts(struct usb_serial_port *port, int on)
 624{
 625        struct cypress_private *priv = usb_get_serial_port_data(port);
 626        /* drop dtr and rts */
 627        spin_lock_irq(&priv->lock);
 628        if (on == 0)
 629                priv->line_control = 0;
 630        else 
 631                priv->line_control = CONTROL_DTR | CONTROL_RTS;
 632        priv->cmd_ctrl = 1;
 633        spin_unlock_irq(&priv->lock);
 634        cypress_write(NULL, port, NULL, 0);
 635}
 636
 637static void cypress_close(struct usb_serial_port *port)
 638{
 639        struct cypress_private *priv = usb_get_serial_port_data(port);
 640        unsigned long flags;
 641
 642        spin_lock_irqsave(&priv->lock, flags);
 643        kfifo_reset_out(&priv->write_fifo);
 644        spin_unlock_irqrestore(&priv->lock, flags);
 645
 646        dev_dbg(&port->dev, "%s - stopping urbs\n", __func__);
 647        usb_kill_urb(port->interrupt_in_urb);
 648        usb_kill_urb(port->interrupt_out_urb);
 649
 650        if (stats)
 651                dev_info(&port->dev, "Statistics: %d Bytes In | %d Bytes Out | %d Commands Issued\n",
 652                        priv->bytes_in, priv->bytes_out, priv->cmd_count);
 653} /* cypress_close */
 654
 655
 656static int cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
 657                                        const unsigned char *buf, int count)
 658{
 659        struct cypress_private *priv = usb_get_serial_port_data(port);
 660
 661        dev_dbg(&port->dev, "%s - %d bytes\n", __func__, count);
 662
 663        /* line control commands, which need to be executed immediately,
 664           are not put into the buffer for obvious reasons.
 665         */
 666        if (priv->cmd_ctrl) {
 667                count = 0;
 668                goto finish;
 669        }
 670
 671        if (!count)
 672                return count;
 673
 674        count = kfifo_in_locked(&priv->write_fifo, buf, count, &priv->lock);
 675
 676finish:
 677        cypress_send(port);
 678
 679        return count;
 680} /* cypress_write */
 681
 682
 683static void cypress_send(struct usb_serial_port *port)
 684{
 685        int count = 0, result, offset, actual_size;
 686        struct cypress_private *priv = usb_get_serial_port_data(port);
 687        struct device *dev = &port->dev;
 688        unsigned long flags;
 689
 690        if (!priv->comm_is_ok)
 691                return;
 692
 693        dev_dbg(dev, "%s - interrupt out size is %d\n", __func__,
 694                port->interrupt_out_size);
 695
 696        spin_lock_irqsave(&priv->lock, flags);
 697        if (priv->write_urb_in_use) {
 698                dev_dbg(dev, "%s - can't write, urb in use\n", __func__);
 699                spin_unlock_irqrestore(&priv->lock, flags);
 700                return;
 701        }
 702        spin_unlock_irqrestore(&priv->lock, flags);
 703
 704        /* clear buffer */
 705        memset(port->interrupt_out_urb->transfer_buffer, 0,
 706                                                port->interrupt_out_size);
 707
 708        spin_lock_irqsave(&priv->lock, flags);
 709        switch (priv->pkt_fmt) {
 710        default:
 711        case packet_format_1:
 712                /* this is for the CY7C64013... */
 713                offset = 2;
 714                port->interrupt_out_buffer[0] = priv->line_control;
 715                break;
 716        case packet_format_2:
 717                /* this is for the CY7C63743... */
 718                offset = 1;
 719                port->interrupt_out_buffer[0] = priv->line_control;
 720                break;
 721        }
 722
 723        if (priv->line_control & CONTROL_RESET)
 724                priv->line_control &= ~CONTROL_RESET;
 725
 726        if (priv->cmd_ctrl) {
 727                priv->cmd_count++;
 728                dev_dbg(dev, "%s - line control command being issued\n", __func__);
 729                spin_unlock_irqrestore(&priv->lock, flags);
 730                goto send;
 731        } else
 732                spin_unlock_irqrestore(&priv->lock, flags);
 733
 734        count = kfifo_out_locked(&priv->write_fifo,
 735                                        &port->interrupt_out_buffer[offset],
 736                                        port->interrupt_out_size - offset,
 737                                        &priv->lock);
 738        if (count == 0)
 739                return;
 740
 741        switch (priv->pkt_fmt) {
 742        default:
 743        case packet_format_1:
 744                port->interrupt_out_buffer[1] = count;
 745                break;
 746        case packet_format_2:
 747                port->interrupt_out_buffer[0] |= count;
 748        }
 749
 750        dev_dbg(dev, "%s - count is %d\n", __func__, count);
 751
 752send:
 753        spin_lock_irqsave(&priv->lock, flags);
 754        priv->write_urb_in_use = 1;
 755        spin_unlock_irqrestore(&priv->lock, flags);
 756
 757        if (priv->cmd_ctrl)
 758                actual_size = 1;
 759        else
 760                actual_size = count +
 761                              (priv->pkt_fmt == packet_format_1 ? 2 : 1);
 762
 763        usb_serial_debug_data(dev, __func__, port->interrupt_out_size,
 764                              port->interrupt_out_urb->transfer_buffer);
 765
 766        usb_fill_int_urb(port->interrupt_out_urb, port->serial->dev,
 767                usb_sndintpipe(port->serial->dev, port->interrupt_out_endpointAddress),
 768                port->interrupt_out_buffer, actual_size,
 769                cypress_write_int_callback, port, priv->write_urb_interval);
 770        result = usb_submit_urb(port->interrupt_out_urb, GFP_ATOMIC);
 771        if (result) {
 772                dev_err_console(port,
 773                                "%s - failed submitting write urb, error %d\n",
 774                                                        __func__, result);
 775                priv->write_urb_in_use = 0;
 776                cypress_set_dead(port);
 777        }
 778
 779        spin_lock_irqsave(&priv->lock, flags);
 780        if (priv->cmd_ctrl)
 781                priv->cmd_ctrl = 0;
 782
 783        /* do not count the line control and size bytes */
 784        priv->bytes_out += count;
 785        spin_unlock_irqrestore(&priv->lock, flags);
 786
 787        usb_serial_port_softint(port);
 788} /* cypress_send */
 789
 790
 791/* returns how much space is available in the soft buffer */
 792static unsigned int cypress_write_room(struct tty_struct *tty)
 793{
 794        struct usb_serial_port *port = tty->driver_data;
 795        struct cypress_private *priv = usb_get_serial_port_data(port);
 796        unsigned int room;
 797        unsigned long flags;
 798
 799        spin_lock_irqsave(&priv->lock, flags);
 800        room = kfifo_avail(&priv->write_fifo);
 801        spin_unlock_irqrestore(&priv->lock, flags);
 802
 803        dev_dbg(&port->dev, "%s - returns %u\n", __func__, room);
 804        return room;
 805}
 806
 807
 808static int cypress_tiocmget(struct tty_struct *tty)
 809{
 810        struct usb_serial_port *port = tty->driver_data;
 811        struct cypress_private *priv = usb_get_serial_port_data(port);
 812        __u8 status, control;
 813        unsigned int result = 0;
 814        unsigned long flags;
 815
 816        spin_lock_irqsave(&priv->lock, flags);
 817        control = priv->line_control;
 818        status = priv->current_status;
 819        spin_unlock_irqrestore(&priv->lock, flags);
 820
 821        result = ((control & CONTROL_DTR)        ? TIOCM_DTR : 0)
 822                | ((control & CONTROL_RTS)       ? TIOCM_RTS : 0)
 823                | ((status & UART_CTS)        ? TIOCM_CTS : 0)
 824                | ((status & UART_DSR)        ? TIOCM_DSR : 0)
 825                | ((status & UART_RI)         ? TIOCM_RI  : 0)
 826                | ((status & UART_CD)         ? TIOCM_CD  : 0);
 827
 828        dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
 829
 830        return result;
 831}
 832
 833
 834static int cypress_tiocmset(struct tty_struct *tty,
 835                               unsigned int set, unsigned int clear)
 836{
 837        struct usb_serial_port *port = tty->driver_data;
 838        struct cypress_private *priv = usb_get_serial_port_data(port);
 839        unsigned long flags;
 840
 841        spin_lock_irqsave(&priv->lock, flags);
 842        if (set & TIOCM_RTS)
 843                priv->line_control |= CONTROL_RTS;
 844        if (set & TIOCM_DTR)
 845                priv->line_control |= CONTROL_DTR;
 846        if (clear & TIOCM_RTS)
 847                priv->line_control &= ~CONTROL_RTS;
 848        if (clear & TIOCM_DTR)
 849                priv->line_control &= ~CONTROL_DTR;
 850        priv->cmd_ctrl = 1;
 851        spin_unlock_irqrestore(&priv->lock, flags);
 852
 853        return cypress_write(tty, port, NULL, 0);
 854}
 855
 856static void cypress_earthmate_init_termios(struct tty_struct *tty)
 857{
 858        tty_encode_baud_rate(tty, 4800, 4800);
 859}
 860
 861static void cypress_set_termios(struct tty_struct *tty,
 862        struct usb_serial_port *port, struct ktermios *old_termios)
 863{
 864        struct cypress_private *priv = usb_get_serial_port_data(port);
 865        struct device *dev = &port->dev;
 866        int data_bits, stop_bits, parity_type, parity_enable;
 867        unsigned int cflag;
 868        unsigned long flags;
 869        __u8 oldlines;
 870        int linechange = 0;
 871
 872        /* Unsupported features need clearing */
 873        tty->termios.c_cflag &= ~(CMSPAR|CRTSCTS);
 874
 875        cflag = tty->termios.c_cflag;
 876
 877        /* set number of data bits, parity, stop bits */
 878        /* when parity is disabled the parity type bit is ignored */
 879
 880        /* 1 means 2 stop bits, 0 means 1 stop bit */
 881        stop_bits = cflag & CSTOPB ? 1 : 0;
 882
 883        if (cflag & PARENB) {
 884                parity_enable = 1;
 885                /* 1 means odd parity, 0 means even parity */
 886                parity_type = cflag & PARODD ? 1 : 0;
 887        } else
 888                parity_enable = parity_type = 0;
 889
 890        data_bits = tty_get_char_size(cflag);
 891
 892        spin_lock_irqsave(&priv->lock, flags);
 893        oldlines = priv->line_control;
 894        if ((cflag & CBAUD) == B0) {
 895                /* drop dtr and rts */
 896                dev_dbg(dev, "%s - dropping the lines, baud rate 0bps\n", __func__);
 897                priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
 898        } else
 899                priv->line_control = (CONTROL_DTR | CONTROL_RTS);
 900        spin_unlock_irqrestore(&priv->lock, flags);
 901
 902        dev_dbg(dev, "%s - sending %d stop_bits, %d parity_enable, %d parity_type, %d data_bits (+5)\n",
 903                __func__, stop_bits, parity_enable, parity_type, data_bits);
 904
 905        cypress_serial_control(tty, port, tty_get_baud_rate(tty),
 906                        data_bits, stop_bits,
 907                        parity_enable, parity_type,
 908                        0, CYPRESS_SET_CONFIG);
 909
 910        /* we perform a CYPRESS_GET_CONFIG so that the current settings are
 911         * filled into the private structure this should confirm that all is
 912         * working if it returns what we just set */
 913        cypress_serial_control(tty, port, 0, 0, 0, 0, 0, 0, CYPRESS_GET_CONFIG);
 914
 915        /* Here we can define custom tty settings for devices; the main tty
 916         * termios flag base comes from empeg.c */
 917
 918        spin_lock_irqsave(&priv->lock, flags);
 919        if (priv->chiptype == CT_EARTHMATE && priv->baud_rate == 4800) {
 920                dev_dbg(dev, "Using custom termios settings for a baud rate of 4800bps.\n");
 921                /* define custom termios settings for NMEA protocol */
 922
 923                tty->termios.c_iflag /* input modes - */
 924                        &= ~(IGNBRK  /* disable ignore break */
 925                        | BRKINT     /* disable break causes interrupt */
 926                        | PARMRK     /* disable mark parity errors */
 927                        | ISTRIP     /* disable clear high bit of input char */
 928                        | INLCR      /* disable translate NL to CR */
 929                        | IGNCR      /* disable ignore CR */
 930                        | ICRNL      /* disable translate CR to NL */
 931                        | IXON);     /* disable enable XON/XOFF flow control */
 932
 933                tty->termios.c_oflag /* output modes */
 934                        &= ~OPOST;    /* disable postprocess output char */
 935
 936                tty->termios.c_lflag /* line discipline modes */
 937                        &= ~(ECHO     /* disable echo input characters */
 938                        | ECHONL      /* disable echo new line */
 939                        | ICANON      /* disable erase, kill, werase, and rprnt
 940                                         special characters */
 941                        | ISIG        /* disable interrupt, quit, and suspend
 942                                         special characters */
 943                        | IEXTEN);    /* disable non-POSIX special characters */
 944        } /* CT_CYPHIDCOM: Application should handle this for device */
 945
 946        linechange = (priv->line_control != oldlines);
 947        spin_unlock_irqrestore(&priv->lock, flags);
 948
 949        /* if necessary, set lines */
 950        if (linechange) {
 951                priv->cmd_ctrl = 1;
 952                cypress_write(tty, port, NULL, 0);
 953        }
 954} /* cypress_set_termios */
 955
 956
 957/* returns amount of data still left in soft buffer */
 958static unsigned int cypress_chars_in_buffer(struct tty_struct *tty)
 959{
 960        struct usb_serial_port *port = tty->driver_data;
 961        struct cypress_private *priv = usb_get_serial_port_data(port);
 962        unsigned int chars;
 963        unsigned long flags;
 964
 965        spin_lock_irqsave(&priv->lock, flags);
 966        chars = kfifo_len(&priv->write_fifo);
 967        spin_unlock_irqrestore(&priv->lock, flags);
 968
 969        dev_dbg(&port->dev, "%s - returns %u\n", __func__, chars);
 970        return chars;
 971}
 972
 973
 974static void cypress_throttle(struct tty_struct *tty)
 975{
 976        struct usb_serial_port *port = tty->driver_data;
 977        struct cypress_private *priv = usb_get_serial_port_data(port);
 978
 979        spin_lock_irq(&priv->lock);
 980        priv->rx_flags = THROTTLED;
 981        spin_unlock_irq(&priv->lock);
 982}
 983
 984
 985static void cypress_unthrottle(struct tty_struct *tty)
 986{
 987        struct usb_serial_port *port = tty->driver_data;
 988        struct cypress_private *priv = usb_get_serial_port_data(port);
 989        int actually_throttled, result;
 990
 991        spin_lock_irq(&priv->lock);
 992        actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
 993        priv->rx_flags = 0;
 994        spin_unlock_irq(&priv->lock);
 995
 996        if (!priv->comm_is_ok)
 997                return;
 998
 999        if (actually_throttled) {
1000                result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
1001                if (result) {
1002                        dev_err(&port->dev, "%s - failed submitting read urb, "
1003                                        "error %d\n", __func__, result);
1004                        cypress_set_dead(port);
1005                }
1006        }
1007}
1008
1009
1010static void cypress_read_int_callback(struct urb *urb)
1011{
1012        struct usb_serial_port *port = urb->context;
1013        struct cypress_private *priv = usb_get_serial_port_data(port);
1014        struct device *dev = &urb->dev->dev;
1015        struct tty_struct *tty;
1016        unsigned char *data = urb->transfer_buffer;
1017        unsigned long flags;
1018        char tty_flag = TTY_NORMAL;
1019        int bytes = 0;
1020        int result;
1021        int i = 0;
1022        int status = urb->status;
1023
1024        switch (status) {
1025        case 0: /* success */
1026                break;
1027        case -ECONNRESET:
1028        case -ENOENT:
1029        case -ESHUTDOWN:
1030                /* precursor to disconnect so just go away */
1031                return;
1032        case -EPIPE:
1033                /* Can't call usb_clear_halt while in_interrupt */
1034                fallthrough;
1035        default:
1036                /* something ugly is going on... */
1037                dev_err(dev, "%s - unexpected nonzero read status received: %d\n",
1038                        __func__, status);
1039                cypress_set_dead(port);
1040                return;
1041        }
1042
1043        spin_lock_irqsave(&priv->lock, flags);
1044        if (priv->rx_flags & THROTTLED) {
1045                dev_dbg(dev, "%s - now throttling\n", __func__);
1046                priv->rx_flags |= ACTUALLY_THROTTLED;
1047                spin_unlock_irqrestore(&priv->lock, flags);
1048                return;
1049        }
1050        spin_unlock_irqrestore(&priv->lock, flags);
1051
1052        tty = tty_port_tty_get(&port->port);
1053        if (!tty) {
1054                dev_dbg(dev, "%s - bad tty pointer - exiting\n", __func__);
1055                return;
1056        }
1057
1058        spin_lock_irqsave(&priv->lock, flags);
1059        result = urb->actual_length;
1060        switch (priv->pkt_fmt) {
1061        default:
1062        case packet_format_1:
1063                /* This is for the CY7C64013... */
1064                priv->current_status = data[0] & 0xF8;
1065                bytes = data[1] + 2;
1066                i = 2;
1067                break;
1068        case packet_format_2:
1069                /* This is for the CY7C63743... */
1070                priv->current_status = data[0] & 0xF8;
1071                bytes = (data[0] & 0x07) + 1;
1072                i = 1;
1073                break;
1074        }
1075        spin_unlock_irqrestore(&priv->lock, flags);
1076        if (result < bytes) {
1077                dev_dbg(dev,
1078                        "%s - wrong packet size - received %d bytes but packet said %d bytes\n",
1079                        __func__, result, bytes);
1080                goto continue_read;
1081        }
1082
1083        usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
1084
1085        spin_lock_irqsave(&priv->lock, flags);
1086        /* check to see if status has changed */
1087        if (priv->current_status != priv->prev_status) {
1088                u8 delta = priv->current_status ^ priv->prev_status;
1089
1090                if (delta & UART_MSR_MASK) {
1091                        if (delta & UART_CTS)
1092                                port->icount.cts++;
1093                        if (delta & UART_DSR)
1094                                port->icount.dsr++;
1095                        if (delta & UART_RI)
1096                                port->icount.rng++;
1097                        if (delta & UART_CD)
1098                                port->icount.dcd++;
1099
1100                        wake_up_interruptible(&port->port.delta_msr_wait);
1101                }
1102
1103                priv->prev_status = priv->current_status;
1104        }
1105        spin_unlock_irqrestore(&priv->lock, flags);
1106
1107        /* hangup, as defined in acm.c... this might be a bad place for it
1108         * though */
1109        if (tty && !C_CLOCAL(tty) && !(priv->current_status & UART_CD)) {
1110                dev_dbg(dev, "%s - calling hangup\n", __func__);
1111                tty_hangup(tty);
1112                goto continue_read;
1113        }
1114
1115        /* There is one error bit... I'm assuming it is a parity error
1116         * indicator as the generic firmware will set this bit to 1 if a
1117         * parity error occurs.
1118         * I can not find reference to any other error events. */
1119        spin_lock_irqsave(&priv->lock, flags);
1120        if (priv->current_status & CYP_ERROR) {
1121                spin_unlock_irqrestore(&priv->lock, flags);
1122                tty_flag = TTY_PARITY;
1123                dev_dbg(dev, "%s - Parity Error detected\n", __func__);
1124        } else
1125                spin_unlock_irqrestore(&priv->lock, flags);
1126
1127        /* process read if there is data other than line status */
1128        if (bytes > i) {
1129                tty_insert_flip_string_fixed_flag(&port->port, data + i,
1130                                tty_flag, bytes - i);
1131                tty_flip_buffer_push(&port->port);
1132        }
1133
1134        spin_lock_irqsave(&priv->lock, flags);
1135        /* control and status byte(s) are also counted */
1136        priv->bytes_in += bytes;
1137        spin_unlock_irqrestore(&priv->lock, flags);
1138
1139continue_read:
1140        tty_kref_put(tty);
1141
1142        /* Continue trying to always read */
1143
1144        if (priv->comm_is_ok) {
1145                usb_fill_int_urb(port->interrupt_in_urb, port->serial->dev,
1146                                usb_rcvintpipe(port->serial->dev,
1147                                        port->interrupt_in_endpointAddress),
1148                                port->interrupt_in_urb->transfer_buffer,
1149                                port->interrupt_in_urb->transfer_buffer_length,
1150                                cypress_read_int_callback, port,
1151                                priv->read_urb_interval);
1152                result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1153                if (result && result != -EPERM) {
1154                        dev_err(dev, "%s - failed resubmitting read urb, error %d\n",
1155                                __func__, result);
1156                        cypress_set_dead(port);
1157                }
1158        }
1159} /* cypress_read_int_callback */
1160
1161
1162static void cypress_write_int_callback(struct urb *urb)
1163{
1164        struct usb_serial_port *port = urb->context;
1165        struct cypress_private *priv = usb_get_serial_port_data(port);
1166        struct device *dev = &urb->dev->dev;
1167        int status = urb->status;
1168
1169        switch (status) {
1170        case 0:
1171                /* success */
1172                break;
1173        case -ECONNRESET:
1174        case -ENOENT:
1175        case -ESHUTDOWN:
1176                /* this urb is terminated, clean up */
1177                dev_dbg(dev, "%s - urb shutting down with status: %d\n",
1178                        __func__, status);
1179                priv->write_urb_in_use = 0;
1180                return;
1181        case -EPIPE:
1182                /* Cannot call usb_clear_halt while in_interrupt */
1183                fallthrough;
1184        default:
1185                dev_err(dev, "%s - unexpected nonzero write status received: %d\n",
1186                        __func__, status);
1187                cypress_set_dead(port);
1188                break;
1189        }
1190        priv->write_urb_in_use = 0;
1191
1192        /* send any buffered data */
1193        cypress_send(port);
1194}
1195
1196module_usb_serial_driver(serial_drivers, id_table_combined);
1197
1198MODULE_AUTHOR(DRIVER_AUTHOR);
1199MODULE_DESCRIPTION(DRIVER_DESC);
1200MODULE_LICENSE("GPL");
1201
1202module_param(stats, bool, S_IRUGO | S_IWUSR);
1203MODULE_PARM_DESC(stats, "Enable statistics or not");
1204module_param(interval, int, S_IRUGO | S_IWUSR);
1205MODULE_PARM_DESC(interval, "Overrides interrupt interval");
1206module_param(unstable_bauds, bool, S_IRUGO | S_IWUSR);
1207MODULE_PARM_DESC(unstable_bauds, "Allow unstable baud rates");
1208