drivers/staging/dgnc/dgnc_driver.c

   1 /*
   2  * Copyright 2003 Digi International (www.digi.com)
   3  *      Scott H Kilau <Scott_Kilau at digi dot com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2, or (at your option)
   8  * any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
  12  * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  13  * PURPOSE.  See the GNU General Public License for more details.
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/pci.h>
  19 #include <linux/slab.h>
  20 #include <linux/sched.h>
  21 #include "dgnc_driver.h"
  22 #include "dgnc_pci.h"
  23 #include "dgnc_mgmt.h"
  24 #include "dgnc_tty.h"
  25 #include "dgnc_cls.h"
  26 #include "dgnc_neo.h"
  27 #include "dgnc_sysfs.h"
  28
  29 MODULE_LICENSE("GPL");
  30 MODULE_AUTHOR("Digi International, http://www.digi.com");
  31 MODULE_DESCRIPTION("Driver for the Digi International Neo and Classic PCI based product line");
  32 MODULE_SUPPORTED_DEVICE("dgnc");
  33
  34 /**************************************************************************
  35  *
  36  * protos for this file
  37  *
  38  */
  39 static int              dgnc_start(void);
  40 static int dgnc_request_irq(struct dgnc_board *brd);
  41 static void dgnc_free_irq(struct dgnc_board *brd);
  42 static struct dgnc_board *dgnc_found_board(struct pci_dev *pdev, int id);
  43 static void             dgnc_cleanup_board(struct dgnc_board *brd);
  44 static void             dgnc_poll_handler(ulong dummy);
  45 static int              dgnc_init_one(struct pci_dev *pdev,
  46                                       const struct pci_device_id *ent);
  47 static int              dgnc_do_remap(struct dgnc_board *brd);
  48
  49 /*
  50  * File operations permitted on Control/Management major.
  51  */
  52 static const struct file_operations dgnc_board_fops = {
  53         .owner          =       THIS_MODULE,
  54         .unlocked_ioctl =       dgnc_mgmt_ioctl,
  55         .open           =       dgnc_mgmt_open,
  56         .release        =       dgnc_mgmt_close
  57 };
  58
  59 /*
  60  * Globals
  61  */
  62 uint                    dgnc_num_boards;
  63 struct dgnc_board               *dgnc_board[MAXBOARDS];
  64 DEFINE_SPINLOCK(dgnc_global_lock);
  65 DEFINE_SPINLOCK(dgnc_poll_lock); /* Poll scheduling lock */
  66 uint                    dgnc_major;
  67 int                     dgnc_poll_tick = 20;    /* Poll interval - 20 ms */
  68
  69 /*
  70  * Static vars.
  71  */
  72 static struct class *dgnc_class;
  73
  74 /*
  75  * Poller stuff
  76  */
  77 static ulong            dgnc_poll_time; /* Time of next poll */
  78 static uint             dgnc_poll_stop; /* Used to tell poller to stop */
  79 static struct timer_list dgnc_poll_timer;
  80
  81 static const struct pci_device_id dgnc_pci_tbl[] = {
  82         {PCI_DEVICE(DIGI_VID, PCI_DEVICE_CLASSIC_4_DID),     .driver_data = 0},
  83         {PCI_DEVICE(DIGI_VID, PCI_DEVICE_CLASSIC_4_422_DID), .driver_data = 1},
  84         {PCI_DEVICE(DIGI_VID, PCI_DEVICE_CLASSIC_8_DID),     .driver_data = 2},
  85         {PCI_DEVICE(DIGI_VID, PCI_DEVICE_CLASSIC_8_422_DID), .driver_data = 3},
  86         {0,}
  87 };
  88 MODULE_DEVICE_TABLE(pci, dgnc_pci_tbl);
  89
  90 struct board_id {
  91         unsigned char *name;
  92         uint maxports;
  93         unsigned int is_pci_express;
  94 };
  95
  96 static struct board_id dgnc_ids[] = {
  97         {       PCI_DEVICE_CLASSIC_4_PCI_NAME,          4,      0       },
  98         {       PCI_DEVICE_CLASSIC_4_422_PCI_NAME,      4,      0       },
  99         {       PCI_DEVICE_CLASSIC_8_PCI_NAME,          8,      0       },
 100         {       PCI_DEVICE_CLASSIC_8_422_PCI_NAME,      8,      0       },
 101         {       PCI_DEVICE_NEO_4_PCI_NAME,              4,      0       },
 102         {       PCI_DEVICE_NEO_8_PCI_NAME,              8,      0       },
 103         {       PCI_DEVICE_NEO_2DB9_PCI_NAME,           2,      0       },
 104         {       PCI_DEVICE_NEO_2DB9PRI_PCI_NAME,        2,      0       },
 105         {       PCI_DEVICE_NEO_2RJ45_PCI_NAME,          2,      0       },
 106         {       PCI_DEVICE_NEO_2RJ45PRI_PCI_NAME,       2,      0       },
 107         {       PCI_DEVICE_NEO_1_422_PCI_NAME,          1,      0       },
 108         {       PCI_DEVICE_NEO_1_422_485_PCI_NAME,      1,      0       },
 109         {       PCI_DEVICE_NEO_2_422_485_PCI_NAME,      2,      0       },
 110         {       PCI_DEVICE_NEO_EXPRESS_8_PCI_NAME,      8,      1       },
 111         {       PCI_DEVICE_NEO_EXPRESS_4_PCI_NAME,      4,      1       },
 112         {       PCI_DEVICE_NEO_EXPRESS_4RJ45_PCI_NAME,  4,      1       },
 113         {       PCI_DEVICE_NEO_EXPRESS_8RJ45_PCI_NAME,  8,      1       },
 114         {       NULL,                                   0,      0       }
 115 };
 116
 117 static struct pci_driver dgnc_driver = {
 118         .name           = "dgnc",
 119         .probe          = dgnc_init_one,
 120         .id_table       = dgnc_pci_tbl,
 121 };
 122
 123 /************************************************************************
 124  *
 125  * Driver load/unload functions
 126  *
 127  ************************************************************************/
 128
 129 static void cleanup(bool sysfiles)
 130 {
 131         int i;
 132         unsigned long flags;
 133
 134         spin_lock_irqsave(&dgnc_poll_lock, flags);
 135         dgnc_poll_stop = 1;
 136         spin_unlock_irqrestore(&dgnc_poll_lock, flags);
 137
 138         /* Turn off poller right away. */
 139         del_timer_sync(&dgnc_poll_timer);
 140
 141         if (sysfiles)
 142                 dgnc_remove_driver_sysfiles(&dgnc_driver);
 143
 144         device_destroy(dgnc_class, MKDEV(dgnc_major, 0));
 145         class_destroy(dgnc_class);
 146         unregister_chrdev(dgnc_major, "dgnc");
 147
 148         for (i = 0; i < dgnc_num_boards; ++i) {
 149                 dgnc_remove_ports_sysfiles(dgnc_board[i]);
 150                 dgnc_cleanup_tty(dgnc_board[i]);
 151                 dgnc_cleanup_board(dgnc_board[i]);
 152         }
 153
 154         dgnc_tty_post_uninit();
 155 }
 156
 157 /*
 158  * dgnc_cleanup_module()
 159  *
 160  * Module unload.  This is where it all ends.
 161  */
 162 static void __exit dgnc_cleanup_module(void)
 163 {
 164         cleanup(true);
 165         pci_unregister_driver(&dgnc_driver);
 166 }
 167
 168 /*
 169  * init_module()
 170  *
 171  * Module load.  This is where it all starts.
 172  */
 173 static int __init dgnc_init_module(void)
 174 {
 175         int rc;
 176
 177         /*
 178          * Initialize global stuff
 179          */
 180         rc = dgnc_start();
 181
 182         if (rc < 0)
 183                 return rc;
 184
 185         /*
 186          * Find and configure all the cards
 187          */
 188         rc = pci_register_driver(&dgnc_driver);
 189         if (rc) {
 190                 pr_warn("WARNING: dgnc driver load failed.  No Digi Neo or Classic boards found.\n");
 191                 cleanup(false);
 192                 return rc;
 193         }
 194         dgnc_create_driver_sysfiles(&dgnc_driver);
 195
 196         return 0;
 197 }
 198
 199 module_init(dgnc_init_module);
 200 module_exit(dgnc_cleanup_module);
 201
 202 /*
 203  * Start of driver.
 204  */
 205 static int dgnc_start(void)
 206 {
 207         int rc = 0;
 208         unsigned long flags;
 209         struct device *dev;
 210
 211         /* make sure timer is initialized before we do anything else */
 212         init_timer(&dgnc_poll_timer);
 213
 214         /*
 215          * Register our base character device into the kernel.
 216          * This allows the download daemon to connect to the downld device
 217          * before any of the boards are init'ed.
 218          *
 219          * Register management/dpa devices
 220          */
 221         rc = register_chrdev(0, "dgnc", &dgnc_board_fops);
 222         if (rc < 0) {
 223                 pr_err(DRVSTR ": Can't register dgnc driver device (%d)\n", rc);
 224                 return rc;
 225         }
 226         dgnc_major = rc;
 227
 228         dgnc_class = class_create(THIS_MODULE, "dgnc_mgmt");
 229         if (IS_ERR(dgnc_class)) {
 230                 rc = PTR_ERR(dgnc_class);
 231                 pr_err(DRVSTR ": Can't create dgnc_mgmt class (%d)\n", rc);
 232                 goto failed_class;
 233         }
 234
 235         dev = device_create(dgnc_class, NULL,
 236                             MKDEV(dgnc_major, 0),
 237                         NULL, "dgnc_mgmt");
 238         if (IS_ERR(dev)) {
 239                 rc = PTR_ERR(dev);
 240                 pr_err(DRVSTR ": Can't create device (%d)\n", rc);
 241                 goto failed_device;
 242         }
 243
 244         /*
 245          * Init any global tty stuff.
 246          */
 247         rc = dgnc_tty_preinit();
 248
 249         if (rc < 0) {
 250                 pr_err(DRVSTR ": tty preinit - not enough memory (%d)\n", rc);
 251                 goto failed_tty;
 252         }
 253
 254         /* Start the poller */
 255         spin_lock_irqsave(&dgnc_poll_lock, flags);
 256         setup_timer(&dgnc_poll_timer, dgnc_poll_handler, 0);
 257         dgnc_poll_time = jiffies + dgnc_jiffies_from_ms(dgnc_poll_tick);
 258         dgnc_poll_timer.expires = dgnc_poll_time;
 259         spin_unlock_irqrestore(&dgnc_poll_lock, flags);
 260
 261         add_timer(&dgnc_poll_timer);
 262
 263         return 0;
 264
 265 failed_tty:
 266         device_destroy(dgnc_class, MKDEV(dgnc_major, 0));
 267 failed_device:
 268         class_destroy(dgnc_class);
 269 failed_class:
 270         unregister_chrdev(dgnc_major, "dgnc");
 271         return rc;
 272 }
 273
 274 /* returns count (>= 0), or negative on error */
 275 static int dgnc_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 276 {
 277         int rc;
 278         struct dgnc_board *brd;
 279
 280         /* wake up and enable device */
 281         rc = pci_enable_device(pdev);
 282
 283         if (rc)
 284                 return -EIO;
 285
 286         brd = dgnc_found_board(pdev, ent->driver_data);
 287         if (IS_ERR(brd))
 288                 return PTR_ERR(brd);
 289
 290         /*
 291          * Do tty device initialization.
 292          */
 293
 294         rc = dgnc_tty_register(brd);
 295         if (rc < 0) {
 296                 pr_err(DRVSTR ": Can't register tty devices (%d)\n", rc);
 297                 goto failed;
 298         }
 299
 300         rc = dgnc_request_irq(brd);
 301         if (rc < 0) {
 302                 pr_err(DRVSTR ": Can't finalize board init (%d)\n", rc);
 303                 goto unregister_tty;
 304         }
 305
 306         rc = dgnc_tty_init(brd);
 307         if (rc < 0) {
 308                 pr_err(DRVSTR ": Can't init tty devices (%d)\n", rc);
 309                 goto free_irq;
 310         }
 311
 312         brd->state = BOARD_READY;
 313         brd->dpastatus = BD_RUNNING;
 314
 315         dgnc_create_ports_sysfiles(brd);
 316
 317         dgnc_board[dgnc_num_boards++] = brd;
 318
 319         return 0;
 320
 321 free_irq:
 322         dgnc_free_irq(brd);
 323 unregister_tty:
 324         dgnc_tty_unregister(brd);
 325
 326 failed:
 327         kfree(brd);
 328
 329         return rc;
 330 }
 331
 332 /*
 333  * dgnc_cleanup_board()
 334  *
 335  * Free all the memory associated with a board
 336  */
 337 static void dgnc_cleanup_board(struct dgnc_board *brd)
 338 {
 339         int i = 0;
 340
 341         if (!brd || brd->magic != DGNC_BOARD_MAGIC)
 342                 return;
 343
 344         switch (brd->device) {
 345         case PCI_DEVICE_CLASSIC_4_DID:
 346         case PCI_DEVICE_CLASSIC_8_DID:
 347         case PCI_DEVICE_CLASSIC_4_422_DID:
 348         case PCI_DEVICE_CLASSIC_8_422_DID:
 349
 350                 /* Tell card not to interrupt anymore. */
 351                 outb(0, brd->iobase + 0x4c);
 352                 break;
 353
 354         default:
 355                 break;
 356         }
 357
 358         if (brd->irq)
 359                 free_irq(brd->irq, brd);
 360
 361         tasklet_kill(&brd->helper_tasklet);
 362
 363         if (brd->re_map_membase) {
 364                 iounmap(brd->re_map_membase);
 365                 brd->re_map_membase = NULL;
 366         }
 367
 368         /* Free all allocated channels structs */
 369         for (i = 0; i < MAXPORTS ; i++) {
 370                 if (brd->channels[i]) {
 371                         kfree(brd->channels[i]->ch_rqueue);
 372                         kfree(brd->channels[i]->ch_equeue);
 373                         kfree(brd->channels[i]->ch_wqueue);
 374                         kfree(brd->channels[i]);
 375                         brd->channels[i] = NULL;
 376                 }
 377         }
 378
 379         dgnc_board[brd->boardnum] = NULL;
 380
 381         kfree(brd);
 382 }
 383
 384 /*
 385  * dgnc_found_board()
 386  *
 387  * A board has been found, init it.
 388  */
 389 static struct dgnc_board *dgnc_found_board(struct pci_dev *pdev, int id)
 390 {
 391         struct dgnc_board *brd;
 392         unsigned int pci_irq;
 393         int i = 0;
 394         int rc = 0;
 395
 396         /* get the board structure and prep it */
 397         brd = kzalloc(sizeof(*brd), GFP_KERNEL);
 398         if (!brd)
 399                 return ERR_PTR(-ENOMEM);
 400
 401         /* store the info for the board we've found */
 402         brd->magic = DGNC_BOARD_MAGIC;
 403         brd->boardnum = dgnc_num_boards;
 404         brd->vendor = dgnc_pci_tbl[id].vendor;
 405         brd->device = dgnc_pci_tbl[id].device;
 406         brd->pdev = pdev;
 407         brd->pci_bus = pdev->bus->number;
 408         brd->pci_slot = PCI_SLOT(pdev->devfn);
 409         brd->name = dgnc_ids[id].name;
 410         brd->maxports = dgnc_ids[id].maxports;
 411         if (dgnc_ids[i].is_pci_express)
 412                 brd->bd_flags |= BD_IS_PCI_EXPRESS;
 413         brd->dpastatus = BD_NOFEP;
 414         init_waitqueue_head(&brd->state_wait);
 415
 416         spin_lock_init(&brd->bd_lock);
 417         spin_lock_init(&brd->bd_intr_lock);
 418
 419         brd->state              = BOARD_FOUND;
 420
 421         /* store which card & revision we have */
 422         pci_read_config_word(pdev, PCI_SUBSYSTEM_VENDOR_ID, &brd->subvendor);
 423         pci_read_config_word(pdev, PCI_SUBSYSTEM_ID, &brd->subdevice);
 424         pci_read_config_byte(pdev, PCI_REVISION_ID, &brd->rev);
 425
 426         pci_irq = pdev->irq;
 427         brd->irq = pci_irq;
 428
 429         switch (brd->device) {
 430         case PCI_DEVICE_CLASSIC_4_DID:
 431         case PCI_DEVICE_CLASSIC_8_DID:
 432         case PCI_DEVICE_CLASSIC_4_422_DID:
 433         case PCI_DEVICE_CLASSIC_8_422_DID:
 434
 435                 brd->dpatype = T_CLASSIC | T_PCIBUS;
 436
 437                 /*
 438                  * For PCI ClassicBoards
 439                  * PCI Local Address (i.e. "resource" number) space
 440                  * 0    PLX Memory Mapped Config
 441                  * 1    PLX I/O Mapped Config
 442                  * 2    I/O Mapped UARTs and Status
 443                  * 3    Memory Mapped VPD
 444                  * 4    Memory Mapped UARTs and Status
 445                  */
 446
 447                 /* get the PCI Base Address Registers */
 448                 brd->membase = pci_resource_start(pdev, 4);
 449
 450                 if (!brd->membase) {
 451                         dev_err(&brd->pdev->dev,
 452                                 "Card has no PCI IO resources, failing.\n");
 453                         rc = -ENODEV;
 454                         goto failed;
 455                 }
 456
 457                 brd->membase_end = pci_resource_end(pdev, 4);
 458
 459                 if (brd->membase & 1)
 460                         brd->membase &= ~3;
 461                 else
 462                         brd->membase &= ~15;
 463
 464                 brd->iobase     = pci_resource_start(pdev, 1);
 465                 brd->iobase_end = pci_resource_end(pdev, 1);
 466                 brd->iobase     = ((unsigned int)(brd->iobase)) & 0xFFFE;
 467
 468                 /* Assign the board_ops struct */
 469                 brd->bd_ops = &dgnc_cls_ops;
 470
 471                 brd->bd_uart_offset = 0x8;
 472                 brd->bd_dividend = 921600;
 473
 474                 rc = dgnc_do_remap(brd);
 475
 476                 if (rc < 0)
 477                         goto failed;
 478
 479                 /* Get and store the board VPD, if it exists */
 480                 brd->bd_ops->vpd(brd);
 481
 482                 /*
 483                  * Enable Local Interrupt 1               (0x1),
 484                  * Local Interrupt 1 Polarity Active high (0x2),
 485                  * Enable PCI interrupt                   (0x40)
 486                  */
 487                 outb(0x43, brd->iobase + 0x4c);
 488
 489                 break;
 490
 491         case PCI_DEVICE_NEO_4_DID:
 492         case PCI_DEVICE_NEO_8_DID:
 493         case PCI_DEVICE_NEO_2DB9_DID:
 494         case PCI_DEVICE_NEO_2DB9PRI_DID:
 495         case PCI_DEVICE_NEO_2RJ45_DID:
 496         case PCI_DEVICE_NEO_2RJ45PRI_DID:
 497         case PCI_DEVICE_NEO_1_422_DID:
 498         case PCI_DEVICE_NEO_1_422_485_DID:
 499         case PCI_DEVICE_NEO_2_422_485_DID:
 500         case PCI_DEVICE_NEO_EXPRESS_8_DID:
 501         case PCI_DEVICE_NEO_EXPRESS_4_DID:
 502         case PCI_DEVICE_NEO_EXPRESS_4RJ45_DID:
 503         case PCI_DEVICE_NEO_EXPRESS_8RJ45_DID:
 504
 505                 /*
 506                  * This chip is set up 100% when we get to it.
 507                  * No need to enable global interrupts or anything.
 508                  */
 509                 if (brd->bd_flags & BD_IS_PCI_EXPRESS)
 510                         brd->dpatype = T_NEO_EXPRESS | T_PCIBUS;
 511                 else
 512                         brd->dpatype = T_NEO | T_PCIBUS;
 513
 514                 /* get the PCI Base Address Registers */
 515                 brd->membase     = pci_resource_start(pdev, 0);
 516                 brd->membase_end = pci_resource_end(pdev, 0);
 517
 518                 if (brd->membase & 1)
 519                         brd->membase &= ~3;
 520                 else
 521                         brd->membase &= ~15;
 522
 523                 /* Assign the board_ops struct */
 524                 brd->bd_ops = &dgnc_neo_ops;
 525
 526                 brd->bd_uart_offset = 0x200;
 527                 brd->bd_dividend = 921600;
 528
 529                 rc = dgnc_do_remap(brd);
 530
 531                 if (rc < 0)
 532                         goto failed;
 533
 534                 /* Read and store the dvid after remapping */
 535                 brd->dvid = readb(brd->re_map_membase + 0x8D);
 536
 537                 /* Get and store the board VPD, if it exists */
 538                 brd->bd_ops->vpd(brd);
 539
 540                 break;
 541
 542         default:
 543                 dev_err(&brd->pdev->dev,
 544                         "Didn't find any compatible Neo/Classic PCI boards.\n");
 545                 rc = -ENXIO;
 546                 goto failed;
 547         }
 548
 549         /* init our poll helper tasklet */
 550         tasklet_init(&brd->helper_tasklet,
 551                      brd->bd_ops->tasklet,
 552                      (unsigned long)brd);
 553
 554         wake_up_interruptible(&brd->state_wait);
 555
 556         return brd;
 557
 558 failed:
 559         kfree(brd);
 560
 561         return ERR_PTR(rc);
 562 }
 563
 564 static int dgnc_request_irq(struct dgnc_board *brd)
 565 {
 566         int rc = 0;
 567
 568         if (brd->irq) {
 569                 rc = request_irq(brd->irq, brd->bd_ops->intr,
 570                                  IRQF_SHARED, "DGNC", brd);
 571
 572                 if (rc) {
 573                         dev_err(&brd->pdev->dev,
 574                                 "Failed to hook IRQ %d\n", brd->irq);
 575                         brd->state = BOARD_FAILED;
 576                         brd->dpastatus = BD_NOFEP;
 577                         rc = -ENODEV;
 578                 }
 579         }
 580         return rc;
 581 }
 582
 583 static void dgnc_free_irq(struct dgnc_board *brd)
 584 {
 585         if (brd->irq)
 586                 free_irq(brd->irq, brd);
 587 }
 588
 589 /*
 590  * Remap PCI memory.
 591  */
 592 static int dgnc_do_remap(struct dgnc_board *brd)
 593 {
 594         int rc = 0;
 595
 596         brd->re_map_membase = ioremap(brd->membase, 0x1000);
 597         if (!brd->re_map_membase)
 598                 rc = -ENOMEM;
 599
 600         return rc;
 601 }
 602
 603 /*
 604  *
 605  * Function:
 606  *
 607  *    dgnc_poll_handler
 608  *
 609  * Author:
 610  *
 611  *    Scott H Kilau
 612  *
 613  * Parameters:
 614  *
 615  *    dummy -- ignored
 616  *
 617  * Return Values:
 618  *
 619  *    none
 620  *
 621  * Description:
 622  *
 623  *    As each timer expires, it determines (a) whether the "transmit"
 624  *    waiter needs to be woken up, and (b) whether the poller needs to
 625  *    be rescheduled.
 626  *
 627  */
 628
 629 static void dgnc_poll_handler(ulong dummy)
 630 {
 631         struct dgnc_board *brd;
 632         unsigned long flags;
 633         int i;
 634         unsigned long new_time;
 635
 636         /* Go thru each board, kicking off a tasklet for each if needed */
 637         for (i = 0; i < dgnc_num_boards; i++) {
 638                 brd = dgnc_board[i];
 639
 640                 spin_lock_irqsave(&brd->bd_lock, flags);
 641
 642                 /* If board is in a failed state don't schedule a tasklet */
 643                 if (brd->state == BOARD_FAILED) {
 644                         spin_unlock_irqrestore(&brd->bd_lock, flags);
 645                         continue;
 646                 }
 647
 648                 /* Schedule a poll helper task */
 649                 tasklet_schedule(&brd->helper_tasklet);
 650
 651                 spin_unlock_irqrestore(&brd->bd_lock, flags);
 652         }
 653
 654         /*
 655          * Schedule ourself back at the nominal wakeup interval.
 656          */
 657         spin_lock_irqsave(&dgnc_poll_lock, flags);
 658         dgnc_poll_time += dgnc_jiffies_from_ms(dgnc_poll_tick);
 659
 660         new_time = dgnc_poll_time - jiffies;
 661
 662         if ((ulong)new_time >= 2 * dgnc_poll_tick)
 663                 dgnc_poll_time = jiffies + dgnc_jiffies_from_ms(dgnc_poll_tick);
 664
 665         setup_timer(&dgnc_poll_timer, dgnc_poll_handler, 0);
 666         dgnc_poll_timer.expires = dgnc_poll_time;
 667         spin_unlock_irqrestore(&dgnc_poll_lock, flags);
 668
 669         if (!dgnc_poll_stop)
 670                 add_timer(&dgnc_poll_timer);
 671 }