linux/drivers/s390/char/tape_core.c
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   1/*
   2 *  drivers/s390/char/tape_core.c
   3 *    basic function of the tape device driver
   4 *
   5 *  S390 and zSeries version
   6 *    Copyright IBM Corp. 2001, 2009
   7 *    Author(s): Carsten Otte <cotte@de.ibm.com>
   8 *               Michael Holzheu <holzheu@de.ibm.com>
   9 *               Tuan Ngo-Anh <ngoanh@de.ibm.com>
  10 *               Martin Schwidefsky <schwidefsky@de.ibm.com>
  11 *               Stefan Bader <shbader@de.ibm.com>
  12 */
  13
  14#define KMSG_COMPONENT "tape"
  15#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  16
  17#include <linux/module.h>
  18#include <linux/init.h>      // for kernel parameters
  19#include <linux/kmod.h>      // for requesting modules
  20#include <linux/spinlock.h>  // for locks
  21#include <linux/vmalloc.h>
  22#include <linux/list.h>
  23#include <linux/slab.h>
  24
  25#include <asm/types.h>       // for variable types
  26
  27#define TAPE_DBF_AREA   tape_core_dbf
  28
  29#include "tape.h"
  30#include "tape_std.h"
  31
  32#define LONG_BUSY_TIMEOUT 180 /* seconds */
  33
  34static void __tape_do_irq (struct ccw_device *, unsigned long, struct irb *);
  35static void tape_delayed_next_request(struct work_struct *);
  36static void tape_long_busy_timeout(unsigned long data);
  37
  38/*
  39 * One list to contain all tape devices of all disciplines, so
  40 * we can assign the devices to minor numbers of the same major
  41 * The list is protected by the rwlock
  42 */
  43static LIST_HEAD(tape_device_list);
  44static DEFINE_RWLOCK(tape_device_lock);
  45
  46/*
  47 * Pointer to debug area.
  48 */
  49debug_info_t *TAPE_DBF_AREA = NULL;
  50EXPORT_SYMBOL(TAPE_DBF_AREA);
  51
  52/*
  53 * Printable strings for tape enumerations.
  54 */
  55const char *tape_state_verbose[TS_SIZE] =
  56{
  57        [TS_UNUSED]   = "UNUSED",
  58        [TS_IN_USE]   = "IN_USE",
  59        [TS_BLKUSE]   = "BLKUSE",
  60        [TS_INIT]     = "INIT  ",
  61        [TS_NOT_OPER] = "NOT_OP"
  62};
  63
  64const char *tape_op_verbose[TO_SIZE] =
  65{
  66        [TO_BLOCK] = "BLK",     [TO_BSB] = "BSB",
  67        [TO_BSF] = "BSF",       [TO_DSE] = "DSE",
  68        [TO_FSB] = "FSB",       [TO_FSF] = "FSF",
  69        [TO_LBL] = "LBL",       [TO_NOP] = "NOP",
  70        [TO_RBA] = "RBA",       [TO_RBI] = "RBI",
  71        [TO_RFO] = "RFO",       [TO_REW] = "REW",
  72        [TO_RUN] = "RUN",       [TO_WRI] = "WRI",
  73        [TO_WTM] = "WTM",       [TO_MSEN] = "MSN",
  74        [TO_LOAD] = "LOA",      [TO_READ_CONFIG] = "RCF",
  75        [TO_READ_ATTMSG] = "RAT",
  76        [TO_DIS] = "DIS",       [TO_ASSIGN] = "ASS",
  77        [TO_UNASSIGN] = "UAS",  [TO_CRYPT_ON] = "CON",
  78        [TO_CRYPT_OFF] = "COF", [TO_KEKL_SET] = "KLS",
  79        [TO_KEKL_QUERY] = "KLQ",[TO_RDC] = "RDC",
  80};
  81
  82static int devid_to_int(struct ccw_dev_id *dev_id)
  83{
  84        return dev_id->devno + (dev_id->ssid << 16);
  85}
  86
  87/*
  88 * Some channel attached tape specific attributes.
  89 *
  90 * FIXME: In the future the first_minor and blocksize attribute should be
  91 *        replaced by a link to the cdev tree.
  92 */
  93static ssize_t
  94tape_medium_state_show(struct device *dev, struct device_attribute *attr, char *buf)
  95{
  96        struct tape_device *tdev;
  97
  98        tdev = dev_get_drvdata(dev);
  99        return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->medium_state);
 100}
 101
 102static
 103DEVICE_ATTR(medium_state, 0444, tape_medium_state_show, NULL);
 104
 105static ssize_t
 106tape_first_minor_show(struct device *dev, struct device_attribute *attr, char *buf)
 107{
 108        struct tape_device *tdev;
 109
 110        tdev = dev_get_drvdata(dev);
 111        return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->first_minor);
 112}
 113
 114static
 115DEVICE_ATTR(first_minor, 0444, tape_first_minor_show, NULL);
 116
 117static ssize_t
 118tape_state_show(struct device *dev, struct device_attribute *attr, char *buf)
 119{
 120        struct tape_device *tdev;
 121
 122        tdev = dev_get_drvdata(dev);
 123        return scnprintf(buf, PAGE_SIZE, "%s\n", (tdev->first_minor < 0) ?
 124                "OFFLINE" : tape_state_verbose[tdev->tape_state]);
 125}
 126
 127static
 128DEVICE_ATTR(state, 0444, tape_state_show, NULL);
 129
 130static ssize_t
 131tape_operation_show(struct device *dev, struct device_attribute *attr, char *buf)
 132{
 133        struct tape_device *tdev;
 134        ssize_t rc;
 135
 136        tdev = dev_get_drvdata(dev);
 137        if (tdev->first_minor < 0)
 138                return scnprintf(buf, PAGE_SIZE, "N/A\n");
 139
 140        spin_lock_irq(get_ccwdev_lock(tdev->cdev));
 141        if (list_empty(&tdev->req_queue))
 142                rc = scnprintf(buf, PAGE_SIZE, "---\n");
 143        else {
 144                struct tape_request *req;
 145
 146                req = list_entry(tdev->req_queue.next, struct tape_request,
 147                        list);
 148                rc = scnprintf(buf,PAGE_SIZE, "%s\n", tape_op_verbose[req->op]);
 149        }
 150        spin_unlock_irq(get_ccwdev_lock(tdev->cdev));
 151        return rc;
 152}
 153
 154static
 155DEVICE_ATTR(operation, 0444, tape_operation_show, NULL);
 156
 157static ssize_t
 158tape_blocksize_show(struct device *dev, struct device_attribute *attr, char *buf)
 159{
 160        struct tape_device *tdev;
 161
 162        tdev = dev_get_drvdata(dev);
 163
 164        return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->char_data.block_size);
 165}
 166
 167static
 168DEVICE_ATTR(blocksize, 0444, tape_blocksize_show, NULL);
 169
 170static struct attribute *tape_attrs[] = {
 171        &dev_attr_medium_state.attr,
 172        &dev_attr_first_minor.attr,
 173        &dev_attr_state.attr,
 174        &dev_attr_operation.attr,
 175        &dev_attr_blocksize.attr,
 176        NULL
 177};
 178
 179static struct attribute_group tape_attr_group = {
 180        .attrs = tape_attrs,
 181};
 182
 183/*
 184 * Tape state functions
 185 */
 186void
 187tape_state_set(struct tape_device *device, enum tape_state newstate)
 188{
 189        const char *str;
 190
 191        if (device->tape_state == TS_NOT_OPER) {
 192                DBF_EVENT(3, "ts_set err: not oper\n");
 193                return;
 194        }
 195        DBF_EVENT(4, "ts. dev:  %x\n", device->first_minor);
 196        DBF_EVENT(4, "old ts:\t\n");
 197        if (device->tape_state < TS_SIZE && device->tape_state >=0 )
 198                str = tape_state_verbose[device->tape_state];
 199        else
 200                str = "UNKNOWN TS";
 201        DBF_EVENT(4, "%s\n", str);
 202        DBF_EVENT(4, "new ts:\t\n");
 203        if (newstate < TS_SIZE && newstate >= 0)
 204                str = tape_state_verbose[newstate];
 205        else
 206                str = "UNKNOWN TS";
 207        DBF_EVENT(4, "%s\n", str);
 208        device->tape_state = newstate;
 209        wake_up(&device->state_change_wq);
 210}
 211
 212void
 213tape_med_state_set(struct tape_device *device, enum tape_medium_state newstate)
 214{
 215        if (device->medium_state == newstate)
 216                return;
 217        switch(newstate){
 218        case MS_UNLOADED:
 219                device->tape_generic_status |= GMT_DR_OPEN(~0);
 220                if (device->medium_state == MS_LOADED)
 221                        pr_info("%s: The tape cartridge has been successfully "
 222                                "unloaded\n", dev_name(&device->cdev->dev));
 223                break;
 224        case MS_LOADED:
 225                device->tape_generic_status &= ~GMT_DR_OPEN(~0);
 226                if (device->medium_state == MS_UNLOADED)
 227                        pr_info("%s: A tape cartridge has been mounted\n",
 228                                dev_name(&device->cdev->dev));
 229                break;
 230        default:
 231                // print nothing
 232                break;
 233        }
 234        device->medium_state = newstate;
 235        wake_up(&device->state_change_wq);
 236}
 237
 238/*
 239 * Stop running ccw. Has to be called with the device lock held.
 240 */
 241static int
 242__tape_cancel_io(struct tape_device *device, struct tape_request *request)
 243{
 244        int retries;
 245        int rc;
 246
 247        /* Check if interrupt has already been processed */
 248        if (request->callback == NULL)
 249                return 0;
 250
 251        rc = 0;
 252        for (retries = 0; retries < 5; retries++) {
 253                rc = ccw_device_clear(device->cdev, (long) request);
 254
 255                switch (rc) {
 256                        case 0:
 257                                request->status = TAPE_REQUEST_DONE;
 258                                return 0;
 259                        case -EBUSY:
 260                                request->status = TAPE_REQUEST_CANCEL;
 261                                schedule_delayed_work(&device->tape_dnr, 0);
 262                                return 0;
 263                        case -ENODEV:
 264                                DBF_EXCEPTION(2, "device gone, retry\n");
 265                                break;
 266                        case -EIO:
 267                                DBF_EXCEPTION(2, "I/O error, retry\n");
 268                                break;
 269                        default:
 270                                BUG();
 271                }
 272        }
 273
 274        return rc;
 275}
 276
 277/*
 278 * Add device into the sorted list, giving it the first
 279 * available minor number.
 280 */
 281static int
 282tape_assign_minor(struct tape_device *device)
 283{
 284        struct tape_device *tmp;
 285        int minor;
 286
 287        minor = 0;
 288        write_lock(&tape_device_lock);
 289        list_for_each_entry(tmp, &tape_device_list, node) {
 290                if (minor < tmp->first_minor)
 291                        break;
 292                minor += TAPE_MINORS_PER_DEV;
 293        }
 294        if (minor >= 256) {
 295                write_unlock(&tape_device_lock);
 296                return -ENODEV;
 297        }
 298        device->first_minor = minor;
 299        list_add_tail(&device->node, &tmp->node);
 300        write_unlock(&tape_device_lock);
 301        return 0;
 302}
 303
 304/* remove device from the list */
 305static void
 306tape_remove_minor(struct tape_device *device)
 307{
 308        write_lock(&tape_device_lock);
 309        list_del_init(&device->node);
 310        device->first_minor = -1;
 311        write_unlock(&tape_device_lock);
 312}
 313
 314/*
 315 * Set a device online.
 316 *
 317 * This function is called by the common I/O layer to move a device from the
 318 * detected but offline into the online state.
 319 * If we return an error (RC < 0) the device remains in the offline state. This
 320 * can happen if the device is assigned somewhere else, for example.
 321 */
 322int
 323tape_generic_online(struct tape_device *device,
 324                   struct tape_discipline *discipline)
 325{
 326        int rc;
 327
 328        DBF_LH(6, "tape_enable_device(%p, %p)\n", device, discipline);
 329
 330        if (device->tape_state != TS_INIT) {
 331                DBF_LH(3, "Tapestate not INIT (%d)\n", device->tape_state);
 332                return -EINVAL;
 333        }
 334
 335        init_timer(&device->lb_timeout);
 336        device->lb_timeout.function = tape_long_busy_timeout;
 337
 338        /* Let the discipline have a go at the device. */
 339        device->discipline = discipline;
 340        if (!try_module_get(discipline->owner)) {
 341                return -EINVAL;
 342        }
 343
 344        rc = discipline->setup_device(device);
 345        if (rc)
 346                goto out;
 347        rc = tape_assign_minor(device);
 348        if (rc)
 349                goto out_discipline;
 350
 351        rc = tapechar_setup_device(device);
 352        if (rc)
 353                goto out_minor;
 354        rc = tapeblock_setup_device(device);
 355        if (rc)
 356                goto out_char;
 357
 358        tape_state_set(device, TS_UNUSED);
 359
 360        DBF_LH(3, "(%08x): Drive set online\n", device->cdev_id);
 361
 362        return 0;
 363
 364out_char:
 365        tapechar_cleanup_device(device);
 366out_minor:
 367        tape_remove_minor(device);
 368out_discipline:
 369        device->discipline->cleanup_device(device);
 370        device->discipline = NULL;
 371out:
 372        module_put(discipline->owner);
 373        return rc;
 374}
 375
 376static void
 377tape_cleanup_device(struct tape_device *device)
 378{
 379        tapeblock_cleanup_device(device);
 380        tapechar_cleanup_device(device);
 381        device->discipline->cleanup_device(device);
 382        module_put(device->discipline->owner);
 383        tape_remove_minor(device);
 384        tape_med_state_set(device, MS_UNKNOWN);
 385}
 386
 387/*
 388 * Suspend device.
 389 *
 390 * Called by the common I/O layer if the drive should be suspended on user
 391 * request. We refuse to suspend if the device is loaded or in use for the
 392 * following reason:
 393 * While the Linux guest is suspended, it might be logged off which causes
 394 * devices to be detached. Tape devices are automatically rewound and unloaded
 395 * during DETACH processing (unless the tape device was attached with the
 396 * NOASSIGN or MULTIUSER option). After rewind/unload, there is no way to
 397 * resume the original state of the tape device, since we would need to
 398 * manually re-load the cartridge which was active at suspend time.
 399 */
 400int tape_generic_pm_suspend(struct ccw_device *cdev)
 401{
 402        struct tape_device *device;
 403
 404        device = dev_get_drvdata(&cdev->dev);
 405        if (!device) {
 406                return -ENODEV;
 407        }
 408
 409        DBF_LH(3, "(%08x): tape_generic_pm_suspend(%p)\n",
 410                device->cdev_id, device);
 411
 412        if (device->medium_state != MS_UNLOADED) {
 413                pr_err("A cartridge is loaded in tape device %s, "
 414                       "refusing to suspend\n", dev_name(&cdev->dev));
 415                return -EBUSY;
 416        }
 417
 418        spin_lock_irq(get_ccwdev_lock(device->cdev));
 419        switch (device->tape_state) {
 420                case TS_INIT:
 421                case TS_NOT_OPER:
 422                case TS_UNUSED:
 423                        spin_unlock_irq(get_ccwdev_lock(device->cdev));
 424                        break;
 425                default:
 426                        pr_err("Tape device %s is busy, refusing to "
 427                               "suspend\n", dev_name(&cdev->dev));
 428                        spin_unlock_irq(get_ccwdev_lock(device->cdev));
 429                        return -EBUSY;
 430        }
 431
 432        DBF_LH(3, "(%08x): Drive suspended.\n", device->cdev_id);
 433        return 0;
 434}
 435
 436/*
 437 * Set device offline.
 438 *
 439 * Called by the common I/O layer if the drive should set offline on user
 440 * request. We may prevent this by returning an error.
 441 * Manual offline is only allowed while the drive is not in use.
 442 */
 443int
 444tape_generic_offline(struct ccw_device *cdev)
 445{
 446        struct tape_device *device;
 447
 448        device = dev_get_drvdata(&cdev->dev);
 449        if (!device) {
 450                return -ENODEV;
 451        }
 452
 453        DBF_LH(3, "(%08x): tape_generic_offline(%p)\n",
 454                device->cdev_id, device);
 455
 456        spin_lock_irq(get_ccwdev_lock(device->cdev));
 457        switch (device->tape_state) {
 458                case TS_INIT:
 459                case TS_NOT_OPER:
 460                        spin_unlock_irq(get_ccwdev_lock(device->cdev));
 461                        break;
 462                case TS_UNUSED:
 463                        tape_state_set(device, TS_INIT);
 464                        spin_unlock_irq(get_ccwdev_lock(device->cdev));
 465                        tape_cleanup_device(device);
 466                        break;
 467                default:
 468                        DBF_EVENT(3, "(%08x): Set offline failed "
 469                                "- drive in use.\n",
 470                                device->cdev_id);
 471                        spin_unlock_irq(get_ccwdev_lock(device->cdev));
 472                        return -EBUSY;
 473        }
 474
 475        DBF_LH(3, "(%08x): Drive set offline.\n", device->cdev_id);
 476        return 0;
 477}
 478
 479/*
 480 * Allocate memory for a new device structure.
 481 */
 482static struct tape_device *
 483tape_alloc_device(void)
 484{
 485        struct tape_device *device;
 486
 487        device = kzalloc(sizeof(struct tape_device), GFP_KERNEL);
 488        if (device == NULL) {
 489                DBF_EXCEPTION(2, "ti:no mem\n");
 490                return ERR_PTR(-ENOMEM);
 491        }
 492        device->modeset_byte = kmalloc(1, GFP_KERNEL | GFP_DMA);
 493        if (device->modeset_byte == NULL) {
 494                DBF_EXCEPTION(2, "ti:no mem\n");
 495                kfree(device);
 496                return ERR_PTR(-ENOMEM);
 497        }
 498        mutex_init(&device->mutex);
 499        INIT_LIST_HEAD(&device->req_queue);
 500        INIT_LIST_HEAD(&device->node);
 501        init_waitqueue_head(&device->state_change_wq);
 502        init_waitqueue_head(&device->wait_queue);
 503        device->tape_state = TS_INIT;
 504        device->medium_state = MS_UNKNOWN;
 505        *device->modeset_byte = 0;
 506        device->first_minor = -1;
 507        atomic_set(&device->ref_count, 1);
 508        INIT_DELAYED_WORK(&device->tape_dnr, tape_delayed_next_request);
 509
 510        return device;
 511}
 512
 513/*
 514 * Get a reference to an existing device structure. This will automatically
 515 * increment the reference count.
 516 */
 517struct tape_device *
 518tape_get_device(struct tape_device *device)
 519{
 520        int count;
 521
 522        count = atomic_inc_return(&device->ref_count);
 523        DBF_EVENT(4, "tape_get_device(%p) = %i\n", device, count);
 524        return device;
 525}
 526
 527/*
 528 * Decrease the reference counter of a devices structure. If the
 529 * reference counter reaches zero free the device structure.
 530 * The function returns a NULL pointer to be used by the caller
 531 * for clearing reference pointers.
 532 */
 533void
 534tape_put_device(struct tape_device *device)
 535{
 536        int count;
 537
 538        count = atomic_dec_return(&device->ref_count);
 539        DBF_EVENT(4, "tape_put_device(%p) -> %i\n", device, count);
 540        BUG_ON(count < 0);
 541        if (count == 0) {
 542                kfree(device->modeset_byte);
 543                kfree(device);
 544        }
 545}
 546
 547/*
 548 * Find tape device by a device index.
 549 */
 550struct tape_device *
 551tape_find_device(int devindex)
 552{
 553        struct tape_device *device, *tmp;
 554
 555        device = ERR_PTR(-ENODEV);
 556        read_lock(&tape_device_lock);
 557        list_for_each_entry(tmp, &tape_device_list, node) {
 558                if (tmp->first_minor / TAPE_MINORS_PER_DEV == devindex) {
 559                        device = tape_get_device(tmp);
 560                        break;
 561                }
 562        }
 563        read_unlock(&tape_device_lock);
 564        return device;
 565}
 566
 567/*
 568 * Driverfs tape probe function.
 569 */
 570int
 571tape_generic_probe(struct ccw_device *cdev)
 572{
 573        struct tape_device *device;
 574        int ret;
 575        struct ccw_dev_id dev_id;
 576
 577        device = tape_alloc_device();
 578        if (IS_ERR(device))
 579                return -ENODEV;
 580        ccw_device_set_options(cdev, CCWDEV_DO_PATHGROUP |
 581                                     CCWDEV_DO_MULTIPATH);
 582        ret = sysfs_create_group(&cdev->dev.kobj, &tape_attr_group);
 583        if (ret) {
 584                tape_put_device(device);
 585                return ret;
 586        }
 587        dev_set_drvdata(&cdev->dev, device);
 588        cdev->handler = __tape_do_irq;
 589        device->cdev = cdev;
 590        ccw_device_get_id(cdev, &dev_id);
 591        device->cdev_id = devid_to_int(&dev_id);
 592        return ret;
 593}
 594
 595static void
 596__tape_discard_requests(struct tape_device *device)
 597{
 598        struct tape_request *   request;
 599        struct list_head *      l, *n;
 600
 601        list_for_each_safe(l, n, &device->req_queue) {
 602                request = list_entry(l, struct tape_request, list);
 603                if (request->status == TAPE_REQUEST_IN_IO)
 604                        request->status = TAPE_REQUEST_DONE;
 605                list_del(&request->list);
 606
 607                /* Decrease ref_count for removed request. */
 608                request->device = NULL;
 609                tape_put_device(device);
 610                request->rc = -EIO;
 611                if (request->callback != NULL)
 612                        request->callback(request, request->callback_data);
 613        }
 614}
 615
 616/*
 617 * Driverfs tape remove function.
 618 *
 619 * This function is called whenever the common I/O layer detects the device
 620 * gone. This can happen at any time and we cannot refuse.
 621 */
 622void
 623tape_generic_remove(struct ccw_device *cdev)
 624{
 625        struct tape_device *    device;
 626
 627        device = dev_get_drvdata(&cdev->dev);
 628        if (!device) {
 629                return;
 630        }
 631        DBF_LH(3, "(%08x): tape_generic_remove(%p)\n", device->cdev_id, cdev);
 632
 633        spin_lock_irq(get_ccwdev_lock(device->cdev));
 634        switch (device->tape_state) {
 635                case TS_INIT:
 636                        tape_state_set(device, TS_NOT_OPER);
 637                case TS_NOT_OPER:
 638                        /*
 639                         * Nothing to do.
 640                         */
 641                        spin_unlock_irq(get_ccwdev_lock(device->cdev));
 642                        break;
 643                case TS_UNUSED:
 644                        /*
 645                         * Need only to release the device.
 646                         */
 647                        tape_state_set(device, TS_NOT_OPER);
 648                        spin_unlock_irq(get_ccwdev_lock(device->cdev));
 649                        tape_cleanup_device(device);
 650                        break;
 651                default:
 652                        /*
 653                         * There may be requests on the queue. We will not get
 654                         * an interrupt for a request that was running. So we
 655                         * just post them all as I/O errors.
 656                         */
 657                        DBF_EVENT(3, "(%08x): Drive in use vanished!\n",
 658                                device->cdev_id);
 659                        pr_warning("%s: A tape unit was detached while in "
 660                                   "use\n", dev_name(&device->cdev->dev));
 661                        tape_state_set(device, TS_NOT_OPER);
 662                        __tape_discard_requests(device);
 663                        spin_unlock_irq(get_ccwdev_lock(device->cdev));
 664                        tape_cleanup_device(device);
 665        }
 666
 667        device = dev_get_drvdata(&cdev->dev);
 668        if (device) {
 669                sysfs_remove_group(&cdev->dev.kobj, &tape_attr_group);
 670                dev_set_drvdata(&cdev->dev, NULL);
 671                tape_put_device(device);
 672        }
 673}
 674
 675/*
 676 * Allocate a new tape ccw request
 677 */
 678struct tape_request *
 679tape_alloc_request(int cplength, int datasize)
 680{
 681        struct tape_request *request;
 682
 683        BUG_ON(datasize > PAGE_SIZE || (cplength*sizeof(struct ccw1)) > PAGE_SIZE);
 684
 685        DBF_LH(6, "tape_alloc_request(%d, %d)\n", cplength, datasize);
 686
 687        request = kzalloc(sizeof(struct tape_request), GFP_KERNEL);
 688        if (request == NULL) {
 689                DBF_EXCEPTION(1, "cqra nomem\n");
 690                return ERR_PTR(-ENOMEM);
 691        }
 692        /* allocate channel program */
 693        if (cplength > 0) {
 694                request->cpaddr = kcalloc(cplength, sizeof(struct ccw1),
 695                                          GFP_ATOMIC | GFP_DMA);
 696                if (request->cpaddr == NULL) {
 697                        DBF_EXCEPTION(1, "cqra nomem\n");
 698                        kfree(request);
 699                        return ERR_PTR(-ENOMEM);
 700                }
 701        }
 702        /* alloc small kernel buffer */
 703        if (datasize > 0) {
 704                request->cpdata = kzalloc(datasize, GFP_KERNEL | GFP_DMA);
 705                if (request->cpdata == NULL) {
 706                        DBF_EXCEPTION(1, "cqra nomem\n");
 707                        kfree(request->cpaddr);
 708                        kfree(request);
 709                        return ERR_PTR(-ENOMEM);
 710                }
 711        }
 712        DBF_LH(6, "New request %p(%p/%p)\n", request, request->cpaddr,
 713                request->cpdata);
 714
 715        return request;
 716}
 717
 718/*
 719 * Free tape ccw request
 720 */
 721void
 722tape_free_request (struct tape_request * request)
 723{
 724        DBF_LH(6, "Free request %p\n", request);
 725
 726        if (request->device)
 727                tape_put_device(request->device);
 728        kfree(request->cpdata);
 729        kfree(request->cpaddr);
 730        kfree(request);
 731}
 732
 733static int
 734__tape_start_io(struct tape_device *device, struct tape_request *request)
 735{
 736        int rc;
 737
 738#ifdef CONFIG_S390_TAPE_BLOCK
 739        if (request->op == TO_BLOCK)
 740                device->discipline->check_locate(device, request);
 741#endif
 742        rc = ccw_device_start(
 743                device->cdev,
 744                request->cpaddr,
 745                (unsigned long) request,
 746                0x00,
 747                request->options
 748        );
 749        if (rc == 0) {
 750                request->status = TAPE_REQUEST_IN_IO;
 751        } else if (rc == -EBUSY) {
 752                /* The common I/O subsystem is currently busy. Retry later. */
 753                request->status = TAPE_REQUEST_QUEUED;
 754                schedule_delayed_work(&device->tape_dnr, 0);
 755                rc = 0;
 756        } else {
 757                /* Start failed. Remove request and indicate failure. */
 758                DBF_EVENT(1, "tape: start request failed with RC = %i\n", rc);
 759        }
 760        return rc;
 761}
 762
 763static void
 764__tape_start_next_request(struct tape_device *device)
 765{
 766        struct list_head *l, *n;
 767        struct tape_request *request;
 768        int rc;
 769
 770        DBF_LH(6, "__tape_start_next_request(%p)\n", device);
 771        /*
 772         * Try to start each request on request queue until one is
 773         * started successful.
 774         */
 775        list_for_each_safe(l, n, &device->req_queue) {
 776                request = list_entry(l, struct tape_request, list);
 777
 778                /*
 779                 * Avoid race condition if bottom-half was triggered more than
 780                 * once.
 781                 */
 782                if (request->status == TAPE_REQUEST_IN_IO)
 783                        return;
 784                /*
 785                 * Request has already been stopped. We have to wait until
 786                 * the request is removed from the queue in the interrupt
 787                 * handling.
 788                 */
 789                if (request->status == TAPE_REQUEST_DONE)
 790                        return;
 791
 792                /*
 793                 * We wanted to cancel the request but the common I/O layer
 794                 * was busy at that time. This can only happen if this
 795                 * function is called by delayed_next_request.
 796                 * Otherwise we start the next request on the queue.
 797                 */
 798                if (request->status == TAPE_REQUEST_CANCEL) {
 799                        rc = __tape_cancel_io(device, request);
 800                } else {
 801                        rc = __tape_start_io(device, request);
 802                }
 803                if (rc == 0)
 804                        return;
 805
 806                /* Set ending status. */
 807                request->rc = rc;
 808                request->status = TAPE_REQUEST_DONE;
 809
 810                /* Remove from request queue. */
 811                list_del(&request->list);
 812
 813                /* Do callback. */
 814                if (request->callback != NULL)
 815                        request->callback(request, request->callback_data);
 816        }
 817}
 818
 819static void
 820tape_delayed_next_request(struct work_struct *work)
 821{
 822        struct tape_device *device =
 823                container_of(work, struct tape_device, tape_dnr.work);
 824
 825        DBF_LH(6, "tape_delayed_next_request(%p)\n", device);
 826        spin_lock_irq(get_ccwdev_lock(device->cdev));
 827        __tape_start_next_request(device);
 828        spin_unlock_irq(get_ccwdev_lock(device->cdev));
 829}
 830
 831static void tape_long_busy_timeout(unsigned long data)
 832{
 833        struct tape_request *request;
 834        struct tape_device *device;
 835
 836        device = (struct tape_device *) data;
 837        spin_lock_irq(get_ccwdev_lock(device->cdev));
 838        request = list_entry(device->req_queue.next, struct tape_request, list);
 839        BUG_ON(request->status != TAPE_REQUEST_LONG_BUSY);
 840        DBF_LH(6, "%08x: Long busy timeout.\n", device->cdev_id);
 841        __tape_start_next_request(device);
 842        device->lb_timeout.data = 0UL;
 843        tape_put_device(device);
 844        spin_unlock_irq(get_ccwdev_lock(device->cdev));
 845}
 846
 847static void
 848__tape_end_request(
 849        struct tape_device *    device,
 850        struct tape_request *   request,
 851        int                     rc)
 852{
 853        DBF_LH(6, "__tape_end_request(%p, %p, %i)\n", device, request, rc);
 854        if (request) {
 855                request->rc = rc;
 856                request->status = TAPE_REQUEST_DONE;
 857
 858                /* Remove from request queue. */
 859                list_del(&request->list);
 860
 861                /* Do callback. */
 862                if (request->callback != NULL)
 863                        request->callback(request, request->callback_data);
 864        }
 865
 866        /* Start next request. */
 867        if (!list_empty(&device->req_queue))
 868                __tape_start_next_request(device);
 869}
 870
 871/*
 872 * Write sense data to dbf
 873 */
 874void
 875tape_dump_sense_dbf(struct tape_device *device, struct tape_request *request,
 876                    struct irb *irb)
 877{
 878        unsigned int *sptr;
 879        const char* op;
 880
 881        if (request != NULL)
 882                op = tape_op_verbose[request->op];
 883        else
 884                op = "---";
 885        DBF_EVENT(3, "DSTAT : %02x   CSTAT: %02x\n",
 886                  irb->scsw.cmd.dstat, irb->scsw.cmd.cstat);
 887        DBF_EVENT(3, "DEVICE: %08x OP\t: %s\n", device->cdev_id, op);
 888        sptr = (unsigned int *) irb->ecw;
 889        DBF_EVENT(3, "%08x %08x\n", sptr[0], sptr[1]);
 890        DBF_EVENT(3, "%08x %08x\n", sptr[2], sptr[3]);
 891        DBF_EVENT(3, "%08x %08x\n", sptr[4], sptr[5]);
 892        DBF_EVENT(3, "%08x %08x\n", sptr[6], sptr[7]);
 893}
 894
 895/*
 896 * I/O helper function. Adds the request to the request queue
 897 * and starts it if the tape is idle. Has to be called with
 898 * the device lock held.
 899 */
 900static int
 901__tape_start_request(struct tape_device *device, struct tape_request *request)
 902{
 903        int rc;
 904
 905        switch (request->op) {
 906                case TO_MSEN:
 907                case TO_ASSIGN:
 908                case TO_UNASSIGN:
 909                case TO_READ_ATTMSG:
 910                case TO_RDC:
 911                        if (device->tape_state == TS_INIT)
 912                                break;
 913                        if (device->tape_state == TS_UNUSED)
 914                                break;
 915                default:
 916                        if (device->tape_state == TS_BLKUSE)
 917                                break;
 918                        if (device->tape_state != TS_IN_USE)
 919                                return -ENODEV;
 920        }
 921
 922        /* Increase use count of device for the added request. */
 923        request->device = tape_get_device(device);
 924
 925        if (list_empty(&device->req_queue)) {
 926                /* No other requests are on the queue. Start this one. */
 927                rc = __tape_start_io(device, request);
 928                if (rc)
 929                        return rc;
 930
 931                DBF_LH(5, "Request %p added for execution.\n", request);
 932                list_add(&request->list, &device->req_queue);
 933        } else {
 934                DBF_LH(5, "Request %p add to queue.\n", request);
 935                request->status = TAPE_REQUEST_QUEUED;
 936                list_add_tail(&request->list, &device->req_queue);
 937        }
 938        return 0;
 939}
 940
 941/*
 942 * Add the request to the request queue, try to start it if the
 943 * tape is idle. Return without waiting for end of i/o.
 944 */
 945int
 946tape_do_io_async(struct tape_device *device, struct tape_request *request)
 947{
 948        int rc;
 949
 950        DBF_LH(6, "tape_do_io_async(%p, %p)\n", device, request);
 951
 952        spin_lock_irq(get_ccwdev_lock(device->cdev));
 953        /* Add request to request queue and try to start it. */
 954        rc = __tape_start_request(device, request);
 955        spin_unlock_irq(get_ccwdev_lock(device->cdev));
 956        return rc;
 957}
 958
 959/*
 960 * tape_do_io/__tape_wake_up
 961 * Add the request to the request queue, try to start it if the
 962 * tape is idle and wait uninterruptible for its completion.
 963 */
 964static void
 965__tape_wake_up(struct tape_request *request, void *data)
 966{
 967        request->callback = NULL;
 968        wake_up((wait_queue_head_t *) data);
 969}
 970
 971int
 972tape_do_io(struct tape_device *device, struct tape_request *request)
 973{
 974        int rc;
 975
 976        spin_lock_irq(get_ccwdev_lock(device->cdev));
 977        /* Setup callback */
 978        request->callback = __tape_wake_up;
 979        request->callback_data = &device->wait_queue;
 980        /* Add request to request queue and try to start it. */
 981        rc = __tape_start_request(device, request);
 982        spin_unlock_irq(get_ccwdev_lock(device->cdev));
 983        if (rc)
 984                return rc;
 985        /* Request added to the queue. Wait for its completion. */
 986        wait_event(device->wait_queue, (request->callback == NULL));
 987        /* Get rc from request */
 988        return request->rc;
 989}
 990
 991/*
 992 * tape_do_io_interruptible/__tape_wake_up_interruptible
 993 * Add the request to the request queue, try to start it if the
 994 * tape is idle and wait uninterruptible for its completion.
 995 */
 996static void
 997__tape_wake_up_interruptible(struct tape_request *request, void *data)
 998{
 999        request->callback = NULL;
1000        wake_up_interruptible((wait_queue_head_t *) data);
1001}
1002
1003int
1004tape_do_io_interruptible(struct tape_device *device,
1005                         struct tape_request *request)
1006{
1007        int rc;
1008
1009        spin_lock_irq(get_ccwdev_lock(device->cdev));
1010        /* Setup callback */
1011        request->callback = __tape_wake_up_interruptible;
1012        request->callback_data = &device->wait_queue;
1013        rc = __tape_start_request(device, request);
1014        spin_unlock_irq(get_ccwdev_lock(device->cdev));
1015        if (rc)
1016                return rc;
1017        /* Request added to the queue. Wait for its completion. */
1018        rc = wait_event_interruptible(device->wait_queue,
1019                                      (request->callback == NULL));
1020        if (rc != -ERESTARTSYS)
1021                /* Request finished normally. */
1022                return request->rc;
1023
1024        /* Interrupted by a signal. We have to stop the current request. */
1025        spin_lock_irq(get_ccwdev_lock(device->cdev));
1026        rc = __tape_cancel_io(device, request);
1027        spin_unlock_irq(get_ccwdev_lock(device->cdev));
1028        if (rc == 0) {
1029                /* Wait for the interrupt that acknowledges the halt. */
1030                do {
1031                        rc = wait_event_interruptible(
1032                                device->wait_queue,
1033                                (request->callback == NULL)
1034                        );
1035                } while (rc == -ERESTARTSYS);
1036
1037                DBF_EVENT(3, "IO stopped on %08x\n", device->cdev_id);
1038                rc = -ERESTARTSYS;
1039        }
1040        return rc;
1041}
1042
1043/*
1044 * Stop running ccw.
1045 */
1046int
1047tape_cancel_io(struct tape_device *device, struct tape_request *request)
1048{
1049        int rc;
1050
1051        spin_lock_irq(get_ccwdev_lock(device->cdev));
1052        rc = __tape_cancel_io(device, request);
1053        spin_unlock_irq(get_ccwdev_lock(device->cdev));
1054        return rc;
1055}
1056
1057/*
1058 * Tape interrupt routine, called from the ccw_device layer
1059 */
1060static void
1061__tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
1062{
1063        struct tape_device *device;
1064        struct tape_request *request;
1065        int rc;
1066
1067        device = dev_get_drvdata(&cdev->dev);
1068        if (device == NULL) {
1069                return;
1070        }
1071        request = (struct tape_request *) intparm;
1072
1073        DBF_LH(6, "__tape_do_irq(device=%p, request=%p)\n", device, request);
1074
1075        /* On special conditions irb is an error pointer */
1076        if (IS_ERR(irb)) {
1077                /* FIXME: What to do with the request? */
1078                switch (PTR_ERR(irb)) {
1079                        case -ETIMEDOUT:
1080                                DBF_LH(1, "(%s): Request timed out\n",
1081                                        dev_name(&cdev->dev));
1082                        case -EIO:
1083                                __tape_end_request(device, request, -EIO);
1084                                break;
1085                        default:
1086                                DBF_LH(1, "(%s): Unexpected i/o error %li\n",
1087                                        dev_name(&cdev->dev),
1088                                        PTR_ERR(irb));
1089                }
1090                return;
1091        }
1092
1093        /*
1094         * If the condition code is not zero and the start function bit is
1095         * still set, this is an deferred error and the last start I/O did
1096         * not succeed. At this point the condition that caused the deferred
1097         * error might still apply. So we just schedule the request to be
1098         * started later.
1099         */
1100        if (irb->scsw.cmd.cc != 0 &&
1101            (irb->scsw.cmd.fctl & SCSW_FCTL_START_FUNC) &&
1102            (request->status == TAPE_REQUEST_IN_IO)) {
1103                DBF_EVENT(3,"(%08x): deferred cc=%i, fctl=%i. restarting\n",
1104                        device->cdev_id, irb->scsw.cmd.cc, irb->scsw.cmd.fctl);
1105                request->status = TAPE_REQUEST_QUEUED;
1106                schedule_delayed_work(&device->tape_dnr, HZ);
1107                return;
1108        }
1109
1110        /* May be an unsolicited irq */
1111        if(request != NULL)
1112                request->rescnt = irb->scsw.cmd.count;
1113        else if ((irb->scsw.cmd.dstat == 0x85 || irb->scsw.cmd.dstat == 0x80) &&
1114                 !list_empty(&device->req_queue)) {
1115                /* Not Ready to Ready after long busy ? */
1116                struct tape_request *req;
1117                req = list_entry(device->req_queue.next,
1118                                 struct tape_request, list);
1119                if (req->status == TAPE_REQUEST_LONG_BUSY) {
1120                        DBF_EVENT(3, "(%08x): del timer\n", device->cdev_id);
1121                        if (del_timer(&device->lb_timeout)) {
1122                                device->lb_timeout.data = 0UL;
1123                                tape_put_device(device);
1124                                __tape_start_next_request(device);
1125                        }
1126                        return;
1127                }
1128        }
1129        if (irb->scsw.cmd.dstat != 0x0c) {
1130                /* Set the 'ONLINE' flag depending on sense byte 1 */
1131                if(*(((__u8 *) irb->ecw) + 1) & SENSE_DRIVE_ONLINE)
1132                        device->tape_generic_status |= GMT_ONLINE(~0);
1133                else
1134                        device->tape_generic_status &= ~GMT_ONLINE(~0);
1135
1136                /*
1137                 * Any request that does not come back with channel end
1138                 * and device end is unusual. Log the sense data.
1139                 */
1140                DBF_EVENT(3,"-- Tape Interrupthandler --\n");
1141                tape_dump_sense_dbf(device, request, irb);
1142        } else {
1143                /* Upon normal completion the device _is_ online */
1144                device->tape_generic_status |= GMT_ONLINE(~0);
1145        }
1146        if (device->tape_state == TS_NOT_OPER) {
1147                DBF_EVENT(6, "tape:device is not operational\n");
1148                return;
1149        }
1150
1151        /*
1152         * Request that were canceled still come back with an interrupt.
1153         * To detect these request the state will be set to TAPE_REQUEST_DONE.
1154         */
1155        if(request != NULL && request->status == TAPE_REQUEST_DONE) {
1156                __tape_end_request(device, request, -EIO);
1157                return;
1158        }
1159
1160        rc = device->discipline->irq(device, request, irb);
1161        /*
1162         * rc < 0 : request finished unsuccessfully.
1163         * rc == TAPE_IO_SUCCESS: request finished successfully.
1164         * rc == TAPE_IO_PENDING: request is still running. Ignore rc.
1165         * rc == TAPE_IO_RETRY: request finished but needs another go.
1166         * rc == TAPE_IO_STOP: request needs to get terminated.
1167         */
1168        switch (rc) {
1169                case TAPE_IO_SUCCESS:
1170                        /* Upon normal completion the device _is_ online */
1171                        device->tape_generic_status |= GMT_ONLINE(~0);
1172                        __tape_end_request(device, request, rc);
1173                        break;
1174                case TAPE_IO_PENDING:
1175                        break;
1176                case TAPE_IO_LONG_BUSY:
1177                        device->lb_timeout.data =
1178                                (unsigned long) tape_get_device(device);
1179                        device->lb_timeout.expires = jiffies +
1180                                LONG_BUSY_TIMEOUT * HZ;
1181                        DBF_EVENT(3, "(%08x): add timer\n", device->cdev_id);
1182                        add_timer(&device->lb_timeout);
1183                        request->status = TAPE_REQUEST_LONG_BUSY;
1184                        break;
1185                case TAPE_IO_RETRY:
1186                        rc = __tape_start_io(device, request);
1187                        if (rc)
1188                                __tape_end_request(device, request, rc);
1189                        break;
1190                case TAPE_IO_STOP:
1191                        rc = __tape_cancel_io(device, request);
1192                        if (rc)
1193                                __tape_end_request(device, request, rc);
1194                        break;
1195                default:
1196                        if (rc > 0) {
1197                                DBF_EVENT(6, "xunknownrc\n");
1198                                __tape_end_request(device, request, -EIO);
1199                        } else {
1200                                __tape_end_request(device, request, rc);
1201                        }
1202                        break;
1203        }
1204}
1205
1206/*
1207 * Tape device open function used by tape_char & tape_block frontends.
1208 */
1209int
1210tape_open(struct tape_device *device)
1211{
1212        int rc;
1213
1214        spin_lock_irq(get_ccwdev_lock(device->cdev));
1215        if (device->tape_state == TS_NOT_OPER) {
1216                DBF_EVENT(6, "TAPE:nodev\n");
1217                rc = -ENODEV;
1218        } else if (device->tape_state == TS_IN_USE) {
1219                DBF_EVENT(6, "TAPE:dbusy\n");
1220                rc = -EBUSY;
1221        } else if (device->tape_state == TS_BLKUSE) {
1222                DBF_EVENT(6, "TAPE:dbusy\n");
1223                rc = -EBUSY;
1224        } else if (device->discipline != NULL &&
1225                   !try_module_get(device->discipline->owner)) {
1226                DBF_EVENT(6, "TAPE:nodisc\n");
1227                rc = -ENODEV;
1228        } else {
1229                tape_state_set(device, TS_IN_USE);
1230                rc = 0;
1231        }
1232        spin_unlock_irq(get_ccwdev_lock(device->cdev));
1233        return rc;
1234}
1235
1236/*
1237 * Tape device release function used by tape_char & tape_block frontends.
1238 */
1239int
1240tape_release(struct tape_device *device)
1241{
1242        spin_lock_irq(get_ccwdev_lock(device->cdev));
1243        if (device->tape_state == TS_IN_USE)
1244                tape_state_set(device, TS_UNUSED);
1245        module_put(device->discipline->owner);
1246        spin_unlock_irq(get_ccwdev_lock(device->cdev));
1247        return 0;
1248}
1249
1250/*
1251 * Execute a magnetic tape command a number of times.
1252 */
1253int
1254tape_mtop(struct tape_device *device, int mt_op, int mt_count)
1255{
1256        tape_mtop_fn fn;
1257        int rc;
1258
1259        DBF_EVENT(6, "TAPE:mtio\n");
1260        DBF_EVENT(6, "TAPE:ioop: %x\n", mt_op);
1261        DBF_EVENT(6, "TAPE:arg:  %x\n", mt_count);
1262
1263        if (mt_op < 0 || mt_op >= TAPE_NR_MTOPS)
1264                return -EINVAL;
1265        fn = device->discipline->mtop_array[mt_op];
1266        if (fn == NULL)
1267                return -EINVAL;
1268
1269        /* We assume that the backends can handle count up to 500. */
1270        if (mt_op == MTBSR  || mt_op == MTFSR  || mt_op == MTFSF  ||
1271            mt_op == MTBSF  || mt_op == MTFSFM || mt_op == MTBSFM) {
1272                rc = 0;
1273                for (; mt_count > 500; mt_count -= 500)
1274                        if ((rc = fn(device, 500)) != 0)
1275                                break;
1276                if (rc == 0)
1277                        rc = fn(device, mt_count);
1278        } else
1279                rc = fn(device, mt_count);
1280        return rc;
1281
1282}
1283
1284/*
1285 * Tape init function.
1286 */
1287static int
1288tape_init (void)
1289{
1290        TAPE_DBF_AREA = debug_register ( "tape", 2, 2, 4*sizeof(long));
1291        debug_register_view(TAPE_DBF_AREA, &debug_sprintf_view);
1292#ifdef DBF_LIKE_HELL
1293        debug_set_level(TAPE_DBF_AREA, 6);
1294#endif
1295        DBF_EVENT(3, "tape init\n");
1296        tape_proc_init();
1297        tapechar_init ();
1298        tapeblock_init ();
1299        return 0;
1300}
1301
1302/*
1303 * Tape exit function.
1304 */
1305static void
1306tape_exit(void)
1307{
1308        DBF_EVENT(6, "tape exit\n");
1309
1310        /* Get rid of the frontends */
1311        tapechar_exit();
1312        tapeblock_exit();
1313        tape_proc_cleanup();
1314        debug_unregister (TAPE_DBF_AREA);
1315}
1316
1317MODULE_AUTHOR("(C) 2001 IBM Deutschland Entwicklung GmbH by Carsten Otte and "
1318              "Michael Holzheu (cotte@de.ibm.com,holzheu@de.ibm.com)");
1319MODULE_DESCRIPTION("Linux on zSeries channel attached tape device driver");
1320MODULE_LICENSE("GPL");
1321
1322module_init(tape_init);
1323module_exit(tape_exit);
1324
1325EXPORT_SYMBOL(tape_generic_remove);
1326EXPORT_SYMBOL(tape_generic_probe);
1327EXPORT_SYMBOL(tape_generic_online);
1328EXPORT_SYMBOL(tape_generic_offline);
1329EXPORT_SYMBOL(tape_generic_pm_suspend);
1330EXPORT_SYMBOL(tape_put_device);
1331EXPORT_SYMBOL(tape_get_device);
1332EXPORT_SYMBOL(tape_state_verbose);
1333EXPORT_SYMBOL(tape_op_verbose);
1334EXPORT_SYMBOL(tape_state_set);
1335EXPORT_SYMBOL(tape_med_state_set);
1336EXPORT_SYMBOL(tape_alloc_request);
1337EXPORT_SYMBOL(tape_free_request);
1338EXPORT_SYMBOL(tape_dump_sense_dbf);
1339EXPORT_SYMBOL(tape_do_io);
1340EXPORT_SYMBOL(tape_do_io_async);
1341EXPORT_SYMBOL(tape_do_io_interruptible);
1342EXPORT_SYMBOL(tape_cancel_io);
1343EXPORT_SYMBOL(tape_mtop);
1344
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