linux/drivers/watchdog/pcwd_usb.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 *      Berkshire USB-PC Watchdog Card Driver
   4 *
   5 *      (c) Copyright 2004-2007 Wim Van Sebroeck <wim@iguana.be>.
   6 *
   7 *      Based on source code of the following authors:
   8 *        Ken Hollis <kenji@bitgate.com>,
   9 *        Alan Cox <alan@lxorguk.ukuu.org.uk>,
  10 *        Matt Domsch <Matt_Domsch@dell.com>,
  11 *        Rob Radez <rob@osinvestor.com>,
  12 *        Greg Kroah-Hartman <greg@kroah.com>
  13 *
  14 *      Neither Wim Van Sebroeck nor Iguana vzw. admit liability nor
  15 *      provide warranty for any of this software. This material is
  16 *      provided "AS-IS" and at no charge.
  17 *
  18 *      Thanks also to Simon Machell at Berkshire Products Inc. for
  19 *      providing the test hardware. More info is available at
  20 *      http://www.berkprod.com/ or http://www.pcwatchdog.com/
  21 */
  22
  23#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  24
  25#include <linux/module.h>       /* For module specific items */
  26#include <linux/moduleparam.h>  /* For new moduleparam's */
  27#include <linux/types.h>        /* For standard types (like size_t) */
  28#include <linux/errno.h>        /* For the -ENODEV/... values */
  29#include <linux/kernel.h>       /* For printk/panic/... */
  30#include <linux/delay.h>        /* For mdelay function */
  31#include <linux/miscdevice.h>   /* For struct miscdevice */
  32#include <linux/watchdog.h>     /* For the watchdog specific items */
  33#include <linux/notifier.h>     /* For notifier support */
  34#include <linux/reboot.h>       /* For reboot_notifier stuff */
  35#include <linux/init.h>         /* For __init/__exit/... */
  36#include <linux/fs.h>           /* For file operations */
  37#include <linux/usb.h>          /* For USB functions */
  38#include <linux/slab.h>         /* For kmalloc, ... */
  39#include <linux/mutex.h>        /* For mutex locking */
  40#include <linux/hid.h>          /* For HID_REQ_SET_REPORT & HID_DT_REPORT */
  41#include <linux/uaccess.h>      /* For copy_to_user/put_user/... */
  42
  43
  44/* Module and Version Information */
  45#define DRIVER_VERSION "1.02"
  46#define DRIVER_AUTHOR "Wim Van Sebroeck <wim@iguana.be>"
  47#define DRIVER_DESC "Berkshire USB-PC Watchdog driver"
  48#define DRIVER_NAME "pcwd_usb"
  49
  50MODULE_AUTHOR(DRIVER_AUTHOR);
  51MODULE_DESCRIPTION(DRIVER_DESC);
  52MODULE_LICENSE("GPL");
  53
  54#define WATCHDOG_HEARTBEAT 0    /* default heartbeat =
  55                                                delay-time from dip-switches */
  56static int heartbeat = WATCHDOG_HEARTBEAT;
  57module_param(heartbeat, int, 0);
  58MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. "
  59        "(0<heartbeat<65536 or 0=delay-time from dip-switches, default="
  60                                __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
  61
  62static bool nowayout = WATCHDOG_NOWAYOUT;
  63module_param(nowayout, bool, 0);
  64MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  65                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  66
  67/* The vendor and product id's for the USB-PC Watchdog card */
  68#define USB_PCWD_VENDOR_ID      0x0c98
  69#define USB_PCWD_PRODUCT_ID     0x1140
  70
  71/* table of devices that work with this driver */
  72static const struct usb_device_id usb_pcwd_table[] = {
  73        { USB_DEVICE(USB_PCWD_VENDOR_ID, USB_PCWD_PRODUCT_ID) },
  74        { }                                     /* Terminating entry */
  75};
  76MODULE_DEVICE_TABLE(usb, usb_pcwd_table);
  77
  78/* according to documentation max. time to process a command for the USB
  79 * watchdog card is 100 or 200 ms, so we give it 250 ms to do it's job */
  80#define USB_COMMAND_TIMEOUT     250
  81
  82/* Watchdog's internal commands */
  83#define CMD_READ_TEMP                   0x02    /* Read Temperature;
  84                                                        Re-trigger Watchdog */
  85#define CMD_TRIGGER                     CMD_READ_TEMP
  86#define CMD_GET_STATUS                  0x04    /* Get Status Information */
  87#define CMD_GET_FIRMWARE_VERSION        0x08    /* Get Firmware Version */
  88#define CMD_GET_DIP_SWITCH_SETTINGS     0x0c    /* Get Dip Switch Settings */
  89#define CMD_READ_WATCHDOG_TIMEOUT       0x18    /* Read Current Watchdog Time */
  90#define CMD_WRITE_WATCHDOG_TIMEOUT      0x19    /* Write Current WatchdogTime */
  91#define CMD_ENABLE_WATCHDOG             0x30    /* Enable / Disable Watchdog */
  92#define CMD_DISABLE_WATCHDOG            CMD_ENABLE_WATCHDOG
  93
  94/* Watchdog's Dip Switch heartbeat values */
  95static const int heartbeat_tbl[] = {
  96        5,      /* OFF-OFF-OFF  =  5 Sec  */
  97        10,     /* OFF-OFF-ON   = 10 Sec  */
  98        30,     /* OFF-ON-OFF   = 30 Sec  */
  99        60,     /* OFF-ON-ON    =  1 Min  */
 100        300,    /* ON-OFF-OFF   =  5 Min  */
 101        600,    /* ON-OFF-ON    = 10 Min  */
 102        1800,   /* ON-ON-OFF    = 30 Min  */
 103        3600,   /* ON-ON-ON     =  1 hour */
 104};
 105
 106/* We can only use 1 card due to the /dev/watchdog restriction */
 107static int cards_found;
 108
 109/* some internal variables */
 110static unsigned long is_active;
 111static char expect_release;
 112
 113/* Structure to hold all of our device specific stuff */
 114struct usb_pcwd_private {
 115        /* save off the usb device pointer */
 116        struct usb_device       *udev;
 117        /* the interface for this device */
 118        struct usb_interface    *interface;
 119
 120        /* the interface number used for cmd's */
 121        unsigned int            interface_number;
 122
 123        /* the buffer to intr data */
 124        unsigned char           *intr_buffer;
 125        /* the dma address for the intr buffer */
 126        dma_addr_t              intr_dma;
 127        /* the size of the intr buffer */
 128        size_t                  intr_size;
 129        /* the urb used for the intr pipe */
 130        struct urb              *intr_urb;
 131
 132        /* The command that is reported back */
 133        unsigned char           cmd_command;
 134        /* The data MSB that is reported back */
 135        unsigned char           cmd_data_msb;
 136        /* The data LSB that is reported back */
 137        unsigned char           cmd_data_lsb;
 138        /* true if we received a report after a command */
 139        atomic_t                cmd_received;
 140
 141        /* Wether or not the device exists */
 142        int                     exists;
 143        /* locks this structure */
 144        struct mutex            mtx;
 145};
 146static struct usb_pcwd_private *usb_pcwd_device;
 147
 148/* prevent races between open() and disconnect() */
 149static DEFINE_MUTEX(disconnect_mutex);
 150
 151/* local function prototypes */
 152static int usb_pcwd_probe(struct usb_interface *interface,
 153                                                const struct usb_device_id *id);
 154static void usb_pcwd_disconnect(struct usb_interface *interface);
 155
 156/* usb specific object needed to register this driver with the usb subsystem */
 157static struct usb_driver usb_pcwd_driver = {
 158        .name =         DRIVER_NAME,
 159        .probe =        usb_pcwd_probe,
 160        .disconnect =   usb_pcwd_disconnect,
 161        .id_table =     usb_pcwd_table,
 162};
 163
 164
 165static void usb_pcwd_intr_done(struct urb *urb)
 166{
 167        struct usb_pcwd_private *usb_pcwd =
 168                                (struct usb_pcwd_private *)urb->context;
 169        unsigned char *data = usb_pcwd->intr_buffer;
 170        struct device *dev = &usb_pcwd->interface->dev;
 171        int retval;
 172
 173        switch (urb->status) {
 174        case 0:                 /* success */
 175                break;
 176        case -ECONNRESET:       /* unlink */
 177        case -ENOENT:
 178        case -ESHUTDOWN:
 179                /* this urb is terminated, clean up */
 180                dev_dbg(dev, "%s - urb shutting down with status: %d",
 181                        __func__, urb->status);
 182                return;
 183        /* -EPIPE:  should clear the halt */
 184        default:                /* error */
 185                dev_dbg(dev, "%s - nonzero urb status received: %d",
 186                        __func__, urb->status);
 187                goto resubmit;
 188        }
 189
 190        dev_dbg(dev, "received following data cmd=0x%02x msb=0x%02x lsb=0x%02x",
 191                data[0], data[1], data[2]);
 192
 193        usb_pcwd->cmd_command  = data[0];
 194        usb_pcwd->cmd_data_msb = data[1];
 195        usb_pcwd->cmd_data_lsb = data[2];
 196
 197        /* notify anyone waiting that the cmd has finished */
 198        atomic_set(&usb_pcwd->cmd_received, 1);
 199
 200resubmit:
 201        retval = usb_submit_urb(urb, GFP_ATOMIC);
 202        if (retval)
 203                pr_err("can't resubmit intr, usb_submit_urb failed with result %d\n",
 204                       retval);
 205}
 206
 207static int usb_pcwd_send_command(struct usb_pcwd_private *usb_pcwd,
 208                unsigned char cmd, unsigned char *msb, unsigned char *lsb)
 209{
 210        int got_response, count;
 211        unsigned char *buf;
 212
 213        /* We will not send any commands if the USB PCWD device does
 214         * not exist */
 215        if ((!usb_pcwd) || (!usb_pcwd->exists))
 216                return -1;
 217
 218        buf = kmalloc(6, GFP_KERNEL);
 219        if (buf == NULL)
 220                return 0;
 221
 222        /* The USB PC Watchdog uses a 6 byte report format.
 223         * The board currently uses only 3 of the six bytes of the report. */
 224        buf[0] = cmd;                   /* Byte 0 = CMD */
 225        buf[1] = *msb;                  /* Byte 1 = Data MSB */
 226        buf[2] = *lsb;                  /* Byte 2 = Data LSB */
 227        buf[3] = buf[4] = buf[5] = 0;   /* All other bytes not used */
 228
 229        dev_dbg(&usb_pcwd->interface->dev,
 230                "sending following data cmd=0x%02x msb=0x%02x lsb=0x%02x",
 231                buf[0], buf[1], buf[2]);
 232
 233        atomic_set(&usb_pcwd->cmd_received, 0);
 234
 235        if (usb_control_msg(usb_pcwd->udev, usb_sndctrlpipe(usb_pcwd->udev, 0),
 236                        HID_REQ_SET_REPORT, HID_DT_REPORT,
 237                        0x0200, usb_pcwd->interface_number, buf, 6,
 238                        USB_COMMAND_TIMEOUT) != 6) {
 239                dev_dbg(&usb_pcwd->interface->dev,
 240                        "usb_pcwd_send_command: error in usb_control_msg for cmd 0x%x 0x%x 0x%x\n",
 241                        cmd, *msb, *lsb);
 242        }
 243        /* wait till the usb card processed the command,
 244         * with a max. timeout of USB_COMMAND_TIMEOUT */
 245        got_response = 0;
 246        for (count = 0; (count < USB_COMMAND_TIMEOUT) && (!got_response);
 247                                                                count++) {
 248                mdelay(1);
 249                if (atomic_read(&usb_pcwd->cmd_received))
 250                        got_response = 1;
 251        }
 252
 253        if ((got_response) && (cmd == usb_pcwd->cmd_command)) {
 254                /* read back response */
 255                *msb = usb_pcwd->cmd_data_msb;
 256                *lsb = usb_pcwd->cmd_data_lsb;
 257        }
 258
 259        kfree(buf);
 260
 261        return got_response;
 262}
 263
 264static int usb_pcwd_start(struct usb_pcwd_private *usb_pcwd)
 265{
 266        unsigned char msb = 0x00;
 267        unsigned char lsb = 0x00;
 268        int retval;
 269
 270        /* Enable Watchdog */
 271        retval = usb_pcwd_send_command(usb_pcwd, CMD_ENABLE_WATCHDOG,
 272                                                                &msb, &lsb);
 273
 274        if ((retval == 0) || (lsb == 0)) {
 275                pr_err("Card did not acknowledge enable attempt\n");
 276                return -1;
 277        }
 278
 279        return 0;
 280}
 281
 282static int usb_pcwd_stop(struct usb_pcwd_private *usb_pcwd)
 283{
 284        unsigned char msb = 0xA5;
 285        unsigned char lsb = 0xC3;
 286        int retval;
 287
 288        /* Disable Watchdog */
 289        retval = usb_pcwd_send_command(usb_pcwd, CMD_DISABLE_WATCHDOG,
 290                                                                &msb, &lsb);
 291
 292        if ((retval == 0) || (lsb != 0)) {
 293                pr_err("Card did not acknowledge disable attempt\n");
 294                return -1;
 295        }
 296
 297        return 0;
 298}
 299
 300static int usb_pcwd_keepalive(struct usb_pcwd_private *usb_pcwd)
 301{
 302        unsigned char dummy;
 303
 304        /* Re-trigger Watchdog */
 305        usb_pcwd_send_command(usb_pcwd, CMD_TRIGGER, &dummy, &dummy);
 306
 307        return 0;
 308}
 309
 310static int usb_pcwd_set_heartbeat(struct usb_pcwd_private *usb_pcwd, int t)
 311{
 312        unsigned char msb = t / 256;
 313        unsigned char lsb = t % 256;
 314
 315        if ((t < 0x0001) || (t > 0xFFFF))
 316                return -EINVAL;
 317
 318        /* Write new heartbeat to watchdog */
 319        usb_pcwd_send_command(usb_pcwd, CMD_WRITE_WATCHDOG_TIMEOUT, &msb, &lsb);
 320
 321        heartbeat = t;
 322        return 0;
 323}
 324
 325static int usb_pcwd_get_temperature(struct usb_pcwd_private *usb_pcwd,
 326                                                        int *temperature)
 327{
 328        unsigned char msb, lsb;
 329
 330        usb_pcwd_send_command(usb_pcwd, CMD_READ_TEMP, &msb, &lsb);
 331
 332        /*
 333         * Convert celsius to fahrenheit, since this was
 334         * the decided 'standard' for this return value.
 335         */
 336        *temperature = (lsb * 9 / 5) + 32;
 337
 338        return 0;
 339}
 340
 341static int usb_pcwd_get_timeleft(struct usb_pcwd_private *usb_pcwd,
 342                                                                int *time_left)
 343{
 344        unsigned char msb, lsb;
 345
 346        /* Read the time that's left before rebooting */
 347        /* Note: if the board is not yet armed then we will read 0xFFFF */
 348        usb_pcwd_send_command(usb_pcwd, CMD_READ_WATCHDOG_TIMEOUT, &msb, &lsb);
 349
 350        *time_left = (msb << 8) + lsb;
 351
 352        return 0;
 353}
 354
 355/*
 356 *      /dev/watchdog handling
 357 */
 358
 359static ssize_t usb_pcwd_write(struct file *file, const char __user *data,
 360                                                size_t len, loff_t *ppos)
 361{
 362        /* See if we got the magic character 'V' and reload the timer */
 363        if (len) {
 364                if (!nowayout) {
 365                        size_t i;
 366
 367                        /* note: just in case someone wrote the magic character
 368                         * five months ago... */
 369                        expect_release = 0;
 370
 371                        /* scan to see whether or not we got the
 372                         * magic character */
 373                        for (i = 0; i != len; i++) {
 374                                char c;
 375                                if (get_user(c, data + i))
 376                                        return -EFAULT;
 377                                if (c == 'V')
 378                                        expect_release = 42;
 379                        }
 380                }
 381
 382                /* someone wrote to us, we should reload the timer */
 383                usb_pcwd_keepalive(usb_pcwd_device);
 384        }
 385        return len;
 386}
 387
 388static long usb_pcwd_ioctl(struct file *file, unsigned int cmd,
 389                                                unsigned long arg)
 390{
 391        void __user *argp = (void __user *)arg;
 392        int __user *p = argp;
 393        static const struct watchdog_info ident = {
 394                .options =              WDIOF_KEEPALIVEPING |
 395                                        WDIOF_SETTIMEOUT |
 396                                        WDIOF_MAGICCLOSE,
 397                .firmware_version =     1,
 398                .identity =             DRIVER_NAME,
 399        };
 400
 401        switch (cmd) {
 402        case WDIOC_GETSUPPORT:
 403                return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 404
 405        case WDIOC_GETSTATUS:
 406        case WDIOC_GETBOOTSTATUS:
 407                return put_user(0, p);
 408
 409        case WDIOC_GETTEMP:
 410        {
 411                int temperature;
 412
 413                if (usb_pcwd_get_temperature(usb_pcwd_device, &temperature))
 414                        return -EFAULT;
 415
 416                return put_user(temperature, p);
 417        }
 418
 419        case WDIOC_SETOPTIONS:
 420        {
 421                int new_options, retval = -EINVAL;
 422
 423                if (get_user(new_options, p))
 424                        return -EFAULT;
 425
 426                if (new_options & WDIOS_DISABLECARD) {
 427                        usb_pcwd_stop(usb_pcwd_device);
 428                        retval = 0;
 429                }
 430
 431                if (new_options & WDIOS_ENABLECARD) {
 432                        usb_pcwd_start(usb_pcwd_device);
 433                        retval = 0;
 434                }
 435
 436                return retval;
 437        }
 438
 439        case WDIOC_KEEPALIVE:
 440                usb_pcwd_keepalive(usb_pcwd_device);
 441                return 0;
 442
 443        case WDIOC_SETTIMEOUT:
 444        {
 445                int new_heartbeat;
 446
 447                if (get_user(new_heartbeat, p))
 448                        return -EFAULT;
 449
 450                if (usb_pcwd_set_heartbeat(usb_pcwd_device, new_heartbeat))
 451                        return -EINVAL;
 452
 453                usb_pcwd_keepalive(usb_pcwd_device);
 454        }
 455                fallthrough;
 456
 457        case WDIOC_GETTIMEOUT:
 458                return put_user(heartbeat, p);
 459
 460        case WDIOC_GETTIMELEFT:
 461        {
 462                int time_left;
 463
 464                if (usb_pcwd_get_timeleft(usb_pcwd_device, &time_left))
 465                        return -EFAULT;
 466
 467                return put_user(time_left, p);
 468        }
 469
 470        default:
 471                return -ENOTTY;
 472        }
 473}
 474
 475static int usb_pcwd_open(struct inode *inode, struct file *file)
 476{
 477        /* /dev/watchdog can only be opened once */
 478        if (test_and_set_bit(0, &is_active))
 479                return -EBUSY;
 480
 481        /* Activate */
 482        usb_pcwd_start(usb_pcwd_device);
 483        usb_pcwd_keepalive(usb_pcwd_device);
 484        return stream_open(inode, file);
 485}
 486
 487static int usb_pcwd_release(struct inode *inode, struct file *file)
 488{
 489        /*
 490         *      Shut off the timer.
 491         */
 492        if (expect_release == 42) {
 493                usb_pcwd_stop(usb_pcwd_device);
 494        } else {
 495                pr_crit("Unexpected close, not stopping watchdog!\n");
 496                usb_pcwd_keepalive(usb_pcwd_device);
 497        }
 498        expect_release = 0;
 499        clear_bit(0, &is_active);
 500        return 0;
 501}
 502
 503/*
 504 *      /dev/temperature handling
 505 */
 506
 507static ssize_t usb_pcwd_temperature_read(struct file *file, char __user *data,
 508                                size_t len, loff_t *ppos)
 509{
 510        int temperature;
 511
 512        if (usb_pcwd_get_temperature(usb_pcwd_device, &temperature))
 513                return -EFAULT;
 514
 515        if (copy_to_user(data, &temperature, 1))
 516                return -EFAULT;
 517
 518        return 1;
 519}
 520
 521static int usb_pcwd_temperature_open(struct inode *inode, struct file *file)
 522{
 523        return stream_open(inode, file);
 524}
 525
 526static int usb_pcwd_temperature_release(struct inode *inode, struct file *file)
 527{
 528        return 0;
 529}
 530
 531/*
 532 *      Notify system
 533 */
 534
 535static int usb_pcwd_notify_sys(struct notifier_block *this, unsigned long code,
 536                                                                void *unused)
 537{
 538        if (code == SYS_DOWN || code == SYS_HALT)
 539                usb_pcwd_stop(usb_pcwd_device); /* Turn the WDT off */
 540
 541        return NOTIFY_DONE;
 542}
 543
 544/*
 545 *      Kernel Interfaces
 546 */
 547
 548static const struct file_operations usb_pcwd_fops = {
 549        .owner =        THIS_MODULE,
 550        .llseek =       no_llseek,
 551        .write =        usb_pcwd_write,
 552        .unlocked_ioctl = usb_pcwd_ioctl,
 553        .compat_ioctl = compat_ptr_ioctl,
 554        .open =         usb_pcwd_open,
 555        .release =      usb_pcwd_release,
 556};
 557
 558static struct miscdevice usb_pcwd_miscdev = {
 559        .minor =        WATCHDOG_MINOR,
 560        .name =         "watchdog",
 561        .fops =         &usb_pcwd_fops,
 562};
 563
 564static const struct file_operations usb_pcwd_temperature_fops = {
 565        .owner =        THIS_MODULE,
 566        .llseek =       no_llseek,
 567        .read =         usb_pcwd_temperature_read,
 568        .open =         usb_pcwd_temperature_open,
 569        .release =      usb_pcwd_temperature_release,
 570};
 571
 572static struct miscdevice usb_pcwd_temperature_miscdev = {
 573        .minor =        TEMP_MINOR,
 574        .name =         "temperature",
 575        .fops =         &usb_pcwd_temperature_fops,
 576};
 577
 578static struct notifier_block usb_pcwd_notifier = {
 579        .notifier_call =        usb_pcwd_notify_sys,
 580};
 581
 582/**
 583 *      usb_pcwd_delete
 584 */
 585static inline void usb_pcwd_delete(struct usb_pcwd_private *usb_pcwd)
 586{
 587        usb_free_urb(usb_pcwd->intr_urb);
 588        usb_free_coherent(usb_pcwd->udev, usb_pcwd->intr_size,
 589                          usb_pcwd->intr_buffer, usb_pcwd->intr_dma);
 590        kfree(usb_pcwd);
 591}
 592
 593/**
 594 *      usb_pcwd_probe
 595 *
 596 *      Called by the usb core when a new device is connected that it thinks
 597 *      this driver might be interested in.
 598 */
 599static int usb_pcwd_probe(struct usb_interface *interface,
 600                                                const struct usb_device_id *id)
 601{
 602        struct usb_device *udev = interface_to_usbdev(interface);
 603        struct usb_host_interface *iface_desc;
 604        struct usb_endpoint_descriptor *endpoint;
 605        struct usb_pcwd_private *usb_pcwd = NULL;
 606        int pipe;
 607        int retval = -ENOMEM;
 608        int got_fw_rev;
 609        unsigned char fw_rev_major, fw_rev_minor;
 610        char fw_ver_str[20];
 611        unsigned char option_switches, dummy;
 612
 613        cards_found++;
 614        if (cards_found > 1) {
 615                pr_err("This driver only supports 1 device\n");
 616                return -ENODEV;
 617        }
 618
 619        /* get the active interface descriptor */
 620        iface_desc = interface->cur_altsetting;
 621
 622        /* check out that we have a HID device */
 623        if (!(iface_desc->desc.bInterfaceClass == USB_CLASS_HID)) {
 624                pr_err("The device isn't a Human Interface Device\n");
 625                return -ENODEV;
 626        }
 627
 628        if (iface_desc->desc.bNumEndpoints < 1)
 629                return -ENODEV;
 630
 631        /* check out the endpoint: it has to be Interrupt & IN */
 632        endpoint = &iface_desc->endpoint[0].desc;
 633
 634        if (!usb_endpoint_is_int_in(endpoint)) {
 635                /* we didn't find a Interrupt endpoint with direction IN */
 636                pr_err("Couldn't find an INTR & IN endpoint\n");
 637                return -ENODEV;
 638        }
 639
 640        /* get a handle to the interrupt data pipe */
 641        pipe = usb_rcvintpipe(udev, endpoint->bEndpointAddress);
 642
 643        /* allocate memory for our device and initialize it */
 644        usb_pcwd = kzalloc(sizeof(struct usb_pcwd_private), GFP_KERNEL);
 645        if (usb_pcwd == NULL)
 646                goto error;
 647
 648        usb_pcwd_device = usb_pcwd;
 649
 650        mutex_init(&usb_pcwd->mtx);
 651        usb_pcwd->udev = udev;
 652        usb_pcwd->interface = interface;
 653        usb_pcwd->interface_number = iface_desc->desc.bInterfaceNumber;
 654        usb_pcwd->intr_size = (le16_to_cpu(endpoint->wMaxPacketSize) > 8 ?
 655                                le16_to_cpu(endpoint->wMaxPacketSize) : 8);
 656
 657        /* set up the memory buffer's */
 658        usb_pcwd->intr_buffer = usb_alloc_coherent(udev, usb_pcwd->intr_size,
 659                                        GFP_KERNEL, &usb_pcwd->intr_dma);
 660        if (!usb_pcwd->intr_buffer) {
 661                pr_err("Out of memory\n");
 662                goto error;
 663        }
 664
 665        /* allocate the urb's */
 666        usb_pcwd->intr_urb = usb_alloc_urb(0, GFP_KERNEL);
 667        if (!usb_pcwd->intr_urb)
 668                goto error;
 669
 670        /* initialise the intr urb's */
 671        usb_fill_int_urb(usb_pcwd->intr_urb, udev, pipe,
 672                        usb_pcwd->intr_buffer, usb_pcwd->intr_size,
 673                        usb_pcwd_intr_done, usb_pcwd, endpoint->bInterval);
 674        usb_pcwd->intr_urb->transfer_dma = usb_pcwd->intr_dma;
 675        usb_pcwd->intr_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 676
 677        /* register our interrupt URB with the USB system */
 678        if (usb_submit_urb(usb_pcwd->intr_urb, GFP_KERNEL)) {
 679                pr_err("Problem registering interrupt URB\n");
 680                retval = -EIO; /* failure */
 681                goto error;
 682        }
 683
 684        /* The device exists and can be communicated with */
 685        usb_pcwd->exists = 1;
 686
 687        /* disable card */
 688        usb_pcwd_stop(usb_pcwd);
 689
 690        /* Get the Firmware Version */
 691        got_fw_rev = usb_pcwd_send_command(usb_pcwd, CMD_GET_FIRMWARE_VERSION,
 692                                                &fw_rev_major, &fw_rev_minor);
 693        if (got_fw_rev)
 694                sprintf(fw_ver_str, "%u.%02u", fw_rev_major, fw_rev_minor);
 695        else
 696                sprintf(fw_ver_str, "<card no answer>");
 697
 698        pr_info("Found card (Firmware: %s) with temp option\n", fw_ver_str);
 699
 700        /* Get switch settings */
 701        usb_pcwd_send_command(usb_pcwd, CMD_GET_DIP_SWITCH_SETTINGS, &dummy,
 702                                                        &option_switches);
 703
 704        pr_info("Option switches (0x%02x): Temperature Reset Enable=%s, Power On Delay=%s\n",
 705                option_switches,
 706                ((option_switches & 0x10) ? "ON" : "OFF"),
 707                ((option_switches & 0x08) ? "ON" : "OFF"));
 708
 709        /* If heartbeat = 0 then we use the heartbeat from the dip-switches */
 710        if (heartbeat == 0)
 711                heartbeat = heartbeat_tbl[(option_switches & 0x07)];
 712
 713        /* Check that the heartbeat value is within it's range ;
 714         * if not reset to the default */
 715        if (usb_pcwd_set_heartbeat(usb_pcwd, heartbeat)) {
 716                usb_pcwd_set_heartbeat(usb_pcwd, WATCHDOG_HEARTBEAT);
 717                pr_info("heartbeat value must be 0<heartbeat<65536, using %d\n",
 718                        WATCHDOG_HEARTBEAT);
 719        }
 720
 721        retval = register_reboot_notifier(&usb_pcwd_notifier);
 722        if (retval != 0) {
 723                pr_err("cannot register reboot notifier (err=%d)\n", retval);
 724                goto error;
 725        }
 726
 727        retval = misc_register(&usb_pcwd_temperature_miscdev);
 728        if (retval != 0) {
 729                pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 730                       TEMP_MINOR, retval);
 731                goto err_out_unregister_reboot;
 732        }
 733
 734        retval = misc_register(&usb_pcwd_miscdev);
 735        if (retval != 0) {
 736                pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 737                       WATCHDOG_MINOR, retval);
 738                goto err_out_misc_deregister;
 739        }
 740
 741        /* we can register the device now, as it is ready */
 742        usb_set_intfdata(interface, usb_pcwd);
 743
 744        pr_info("initialized. heartbeat=%d sec (nowayout=%d)\n",
 745                heartbeat, nowayout);
 746
 747        return 0;
 748
 749err_out_misc_deregister:
 750        misc_deregister(&usb_pcwd_temperature_miscdev);
 751err_out_unregister_reboot:
 752        unregister_reboot_notifier(&usb_pcwd_notifier);
 753error:
 754        if (usb_pcwd)
 755                usb_pcwd_delete(usb_pcwd);
 756        usb_pcwd_device = NULL;
 757        return retval;
 758}
 759
 760
 761/**
 762 *      usb_pcwd_disconnect
 763 *
 764 *      Called by the usb core when the device is removed from the system.
 765 *
 766 *      This routine guarantees that the driver will not submit any more urbs
 767 *      by clearing dev->udev.
 768 */
 769static void usb_pcwd_disconnect(struct usb_interface *interface)
 770{
 771        struct usb_pcwd_private *usb_pcwd;
 772
 773        /* prevent races with open() */
 774        mutex_lock(&disconnect_mutex);
 775
 776        usb_pcwd = usb_get_intfdata(interface);
 777        usb_set_intfdata(interface, NULL);
 778
 779        mutex_lock(&usb_pcwd->mtx);
 780
 781        /* Stop the timer before we leave */
 782        if (!nowayout)
 783                usb_pcwd_stop(usb_pcwd);
 784
 785        /* We should now stop communicating with the USB PCWD device */
 786        usb_pcwd->exists = 0;
 787
 788        /* Deregister */
 789        misc_deregister(&usb_pcwd_miscdev);
 790        misc_deregister(&usb_pcwd_temperature_miscdev);
 791        unregister_reboot_notifier(&usb_pcwd_notifier);
 792
 793        mutex_unlock(&usb_pcwd->mtx);
 794
 795        /* Delete the USB PCWD device */
 796        usb_pcwd_delete(usb_pcwd);
 797
 798        cards_found--;
 799
 800        mutex_unlock(&disconnect_mutex);
 801
 802        pr_info("USB PC Watchdog disconnected\n");
 803}
 804
 805module_usb_driver(usb_pcwd_driver);
 806