drivers/misc/cxl/file.c

   1 /*
   2  * Copyright 2014 IBM Corp.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version
   7  * 2 of the License, or (at your option) any later version.
   8  */
   9
  10 #include <linux/spinlock.h>
  11 #include <linux/module.h>
  12 #include <linux/export.h>
  13 #include <linux/kernel.h>
  14 #include <linux/bitmap.h>
  15 #include <linux/sched.h>
  16 #include <linux/poll.h>
  17 #include <linux/pid.h>
  18 #include <linux/fs.h>
  19 #include <linux/mm.h>
  20 #include <linux/slab.h>
  21 #include <asm/cputable.h>
  22 #include <asm/current.h>
  23 #include <asm/copro.h>
  24
  25 #include "cxl.h"
  26 #include "trace.h"
  27
  28 #define CXL_NUM_MINORS 256 /* Total to reserve */
  29
  30 #define CXL_AFU_MINOR_D(afu) (CXL_CARD_MINOR(afu->adapter) + 1 + (3 * afu->slice))
  31 #define CXL_AFU_MINOR_M(afu) (CXL_AFU_MINOR_D(afu) + 1)
  32 #define CXL_AFU_MINOR_S(afu) (CXL_AFU_MINOR_D(afu) + 2)
  33 #define CXL_AFU_MKDEV_D(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_D(afu))
  34 #define CXL_AFU_MKDEV_M(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_M(afu))
  35 #define CXL_AFU_MKDEV_S(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_S(afu))
  36
  37 #define CXL_DEVT_AFU(dev) ((MINOR(dev) % CXL_DEV_MINORS - 1) / 3)
  38
  39 #define CXL_DEVT_IS_CARD(dev) (MINOR(dev) % CXL_DEV_MINORS == 0)
  40
  41 static dev_t cxl_dev;
  42
  43 static struct class *cxl_class;
  44
  45 static int __afu_open(struct inode *inode, struct file *file, bool master)
  46 {
  47         struct cxl *adapter;
  48         struct cxl_afu *afu;
  49         struct cxl_context *ctx;
  50         int adapter_num = CXL_DEVT_ADAPTER(inode->i_rdev);
  51         int slice = CXL_DEVT_AFU(inode->i_rdev);
  52         int rc = -ENODEV;
  53
  54         pr_devel("afu_open afu%i.%i\n", slice, adapter_num);
  55
  56         if (!(adapter = get_cxl_adapter(adapter_num)))
  57                 return -ENODEV;
  58
  59         if (slice > adapter->slices)
  60                 goto err_put_adapter;
  61
  62         spin_lock(&adapter->afu_list_lock);
  63         if (!(afu = adapter->afu[slice])) {
  64                 spin_unlock(&adapter->afu_list_lock);
  65                 goto err_put_adapter;
  66         }
  67
  68         /*
  69          * taking a ref to the afu so that it doesn't go away
  70          * for rest of the function. This ref is released before
  71          * we return.
  72          */
  73         cxl_afu_get(afu);
  74         spin_unlock(&adapter->afu_list_lock);
  75
  76         if (!afu->current_mode)
  77                 goto err_put_afu;
  78
  79         if (!cxl_ops->link_ok(adapter, afu)) {
  80                 rc = -EIO;
  81                 goto err_put_afu;
  82         }
  83
  84         if (!(ctx = cxl_context_alloc())) {
  85                 rc = -ENOMEM;
  86                 goto err_put_afu;
  87         }
  88
  89         rc = cxl_context_init(ctx, afu, master);
  90         if (rc)
  91                 goto err_put_afu;
  92
  93         cxl_context_set_mapping(ctx, inode->i_mapping);
  94
  95         pr_devel("afu_open pe: %i\n", ctx->pe);
  96         file->private_data = ctx;
  97         cxl_ctx_get();
  98
  99         /* indicate success */
 100         rc = 0;
 101
 102 err_put_afu:
 103         /* release the ref taken earlier */
 104         cxl_afu_put(afu);
 105 err_put_adapter:
 106         put_device(&adapter->dev);
 107         return rc;
 108 }
 109
 110 int afu_open(struct inode *inode, struct file *file)
 111 {
 112         return __afu_open(inode, file, false);
 113 }
 114
 115 static int afu_master_open(struct inode *inode, struct file *file)
 116 {
 117         return __afu_open(inode, file, true);
 118 }
 119
 120 int afu_release(struct inode *inode, struct file *file)
 121 {
 122         struct cxl_context *ctx = file->private_data;
 123
 124         pr_devel("%s: closing cxl file descriptor. pe: %i\n",
 125                  __func__, ctx->pe);
 126         cxl_context_detach(ctx);
 127
 128
 129         /*
 130          * Delete the context's mapping pointer, unless it's created by the
 131          * kernel API, in which case leave it so it can be freed by reclaim_ctx()
 132          */
 133         if (!ctx->kernelapi) {
 134                 mutex_lock(&ctx->mapping_lock);
 135                 ctx->mapping = NULL;
 136                 mutex_unlock(&ctx->mapping_lock);
 137         }
 138
 139         /*
 140          * At this this point all bottom halfs have finished and we should be
 141          * getting no more IRQs from the hardware for this context.  Once it's
 142          * removed from the IDR (and RCU synchronised) it's safe to free the
 143          * sstp and context.
 144          */
 145         cxl_context_free(ctx);
 146
 147         return 0;
 148 }
 149
 150 static long afu_ioctl_start_work(struct cxl_context *ctx,
 151                                  struct cxl_ioctl_start_work __user *uwork)
 152 {
 153         struct cxl_ioctl_start_work work;
 154         u64 amr = 0;
 155         int rc;
 156
 157         pr_devel("%s: pe: %i\n", __func__, ctx->pe);
 158
 159         /* Do this outside the status_mutex to avoid a circular dependency with
 160          * the locking in cxl_mmap_fault() */
 161         if (copy_from_user(&work, uwork,
 162                            sizeof(struct cxl_ioctl_start_work))) {
 163                 rc = -EFAULT;
 164                 goto out;
 165         }
 166
 167         mutex_lock(&ctx->status_mutex);
 168         if (ctx->status != OPENED) {
 169                 rc = -EIO;
 170                 goto out;
 171         }
 172
 173         /*
 174          * if any of the reserved fields are set or any of the unused
 175          * flags are set it's invalid
 176          */
 177         if (work.reserved1 || work.reserved2 || work.reserved3 ||
 178             work.reserved4 || work.reserved5 || work.reserved6 ||
 179             (work.flags & ~CXL_START_WORK_ALL)) {
 180                 rc = -EINVAL;
 181                 goto out;
 182         }
 183
 184         if (!(work.flags & CXL_START_WORK_NUM_IRQS))
 185                 work.num_interrupts = ctx->afu->pp_irqs;
 186         else if ((work.num_interrupts < ctx->afu->pp_irqs) ||
 187                  (work.num_interrupts > ctx->afu->irqs_max)) {
 188                 rc =  -EINVAL;
 189                 goto out;
 190         }
 191         if ((rc = afu_register_irqs(ctx, work.num_interrupts)))
 192                 goto out;
 193
 194         if (work.flags & CXL_START_WORK_AMR)
 195                 amr = work.amr & mfspr(SPRN_UAMOR);
 196
 197         ctx->mmio_err_ff = !!(work.flags & CXL_START_WORK_ERR_FF);
 198
 199         /*
 200          * Increment the mapped context count for adapter. This also checks
 201          * if adapter_context_lock is taken.
 202          */
 203         rc = cxl_adapter_context_get(ctx->afu->adapter);
 204         if (rc) {
 205                 afu_release_irqs(ctx, ctx);
 206                 goto out;
 207         }
 208
 209         /*
 210          * We grab the PID here and not in the file open to allow for the case
 211          * where a process (master, some daemon, etc) has opened the chardev on
 212          * behalf of another process, so the AFU's mm gets bound to the process
 213          * that performs this ioctl and not the process that opened the file.
 214          * Also we grab the PID of the group leader so that if the task that
 215          * has performed the attach operation exits the mm context of the
 216          * process is still accessible.
 217          */
 218         ctx->pid = get_task_pid(current, PIDTYPE_PID);
 219         ctx->glpid = get_task_pid(current->group_leader, PIDTYPE_PID);
 220
 221
 222         trace_cxl_attach(ctx, work.work_element_descriptor, work.num_interrupts, amr);
 223
 224         if ((rc = cxl_ops->attach_process(ctx, false, work.work_element_descriptor,
 225                                                         amr))) {
 226                 afu_release_irqs(ctx, ctx);
 227                 cxl_adapter_context_put(ctx->afu->adapter);
 228                 put_pid(ctx->glpid);
 229                 put_pid(ctx->pid);
 230                 ctx->glpid = ctx->pid = NULL;
 231                 goto out;
 232         }
 233
 234         ctx->status = STARTED;
 235         rc = 0;
 236 out:
 237         mutex_unlock(&ctx->status_mutex);
 238         return rc;
 239 }
 240
 241 static long afu_ioctl_process_element(struct cxl_context *ctx,
 242                                       int __user *upe)
 243 {
 244         pr_devel("%s: pe: %i\n", __func__, ctx->pe);
 245
 246         if (copy_to_user(upe, &ctx->external_pe, sizeof(__u32)))
 247                 return -EFAULT;
 248
 249         return 0;
 250 }
 251
 252 static long afu_ioctl_get_afu_id(struct cxl_context *ctx,
 253                                  struct cxl_afu_id __user *upafuid)
 254 {
 255         struct cxl_afu_id afuid = { 0 };
 256
 257         afuid.card_id = ctx->afu->adapter->adapter_num;
 258         afuid.afu_offset = ctx->afu->slice;
 259         afuid.afu_mode = ctx->afu->current_mode;
 260
 261         /* set the flag bit in case the afu is a slave */
 262         if (ctx->afu->current_mode == CXL_MODE_DIRECTED && !ctx->master)
 263                 afuid.flags |= CXL_AFUID_FLAG_SLAVE;
 264
 265         if (copy_to_user(upafuid, &afuid, sizeof(afuid)))
 266                 return -EFAULT;
 267
 268         return 0;
 269 }
 270
 271 long afu_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 272 {
 273         struct cxl_context *ctx = file->private_data;
 274
 275         if (ctx->status == CLOSED)
 276                 return -EIO;
 277
 278         if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu))
 279                 return -EIO;
 280
 281         pr_devel("afu_ioctl\n");
 282         switch (cmd) {
 283         case CXL_IOCTL_START_WORK:
 284                 return afu_ioctl_start_work(ctx, (struct cxl_ioctl_start_work __user *)arg);
 285         case CXL_IOCTL_GET_PROCESS_ELEMENT:
 286                 return afu_ioctl_process_element(ctx, (__u32 __user *)arg);
 287         case CXL_IOCTL_GET_AFU_ID:
 288                 return afu_ioctl_get_afu_id(ctx, (struct cxl_afu_id __user *)
 289                                             arg);
 290         }
 291         return -EINVAL;
 292 }
 293
 294 static long afu_compat_ioctl(struct file *file, unsigned int cmd,
 295                              unsigned long arg)
 296 {
 297         return afu_ioctl(file, cmd, arg);
 298 }
 299
 300 int afu_mmap(struct file *file, struct vm_area_struct *vm)
 301 {
 302         struct cxl_context *ctx = file->private_data;
 303
 304         /* AFU must be started before we can MMIO */
 305         if (ctx->status != STARTED)
 306                 return -EIO;
 307
 308         if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu))
 309                 return -EIO;
 310
 311         return cxl_context_iomap(ctx, vm);
 312 }
 313
 314 static inline bool ctx_event_pending(struct cxl_context *ctx)
 315 {
 316         if (ctx->pending_irq || ctx->pending_fault || ctx->pending_afu_err)
 317                 return true;
 318
 319         if (ctx->afu_driver_ops && atomic_read(&ctx->afu_driver_events))
 320                 return true;
 321
 322         return false;
 323 }
 324
 325 unsigned int afu_poll(struct file *file, struct poll_table_struct *poll)
 326 {
 327         struct cxl_context *ctx = file->private_data;
 328         int mask = 0;
 329         unsigned long flags;
 330
 331
 332         poll_wait(file, &ctx->wq, poll);
 333
 334         pr_devel("afu_poll wait done pe: %i\n", ctx->pe);
 335
 336         spin_lock_irqsave(&ctx->lock, flags);
 337         if (ctx_event_pending(ctx))
 338                 mask |= POLLIN | POLLRDNORM;
 339         else if (ctx->status == CLOSED)
 340                 /* Only error on closed when there are no futher events pending
 341                  */
 342                 mask |= POLLERR;
 343         spin_unlock_irqrestore(&ctx->lock, flags);
 344
 345         pr_devel("afu_poll pe: %i returning %#x\n", ctx->pe, mask);
 346
 347         return mask;
 348 }
 349
 350 static ssize_t afu_driver_event_copy(struct cxl_context *ctx,
 351                                      char __user *buf,
 352                                      struct cxl_event *event,
 353                                      struct cxl_event_afu_driver_reserved *pl)
 354 {
 355         /* Check event */
 356         if (!pl) {
 357                 ctx->afu_driver_ops->event_delivered(ctx, pl, -EINVAL);
 358                 return -EFAULT;
 359         }
 360
 361         /* Check event size */
 362         event->header.size += pl->data_size;
 363         if (event->header.size > CXL_READ_MIN_SIZE) {
 364                 ctx->afu_driver_ops->event_delivered(ctx, pl, -EINVAL);
 365                 return -EFAULT;
 366         }
 367
 368         /* Copy event header */
 369         if (copy_to_user(buf, event, sizeof(struct cxl_event_header))) {
 370                 ctx->afu_driver_ops->event_delivered(ctx, pl, -EFAULT);
 371                 return -EFAULT;
 372         }
 373
 374         /* Copy event data */
 375         buf += sizeof(struct cxl_event_header);
 376         if (copy_to_user(buf, &pl->data, pl->data_size)) {
 377                 ctx->afu_driver_ops->event_delivered(ctx, pl, -EFAULT);
 378                 return -EFAULT;
 379         }
 380
 381         ctx->afu_driver_ops->event_delivered(ctx, pl, 0); /* Success */
 382         return event->header.size;
 383 }
 384
 385 ssize_t afu_read(struct file *file, char __user *buf, size_t count,
 386                         loff_t *off)
 387 {
 388         struct cxl_context *ctx = file->private_data;
 389         struct cxl_event_afu_driver_reserved *pl = NULL;
 390         struct cxl_event event;
 391         unsigned long flags;
 392         int rc;
 393         DEFINE_WAIT(wait);
 394
 395         if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu))
 396                 return -EIO;
 397
 398         if (count < CXL_READ_MIN_SIZE)
 399                 return -EINVAL;
 400
 401         spin_lock_irqsave(&ctx->lock, flags);
 402
 403         for (;;) {
 404                 prepare_to_wait(&ctx->wq, &wait, TASK_INTERRUPTIBLE);
 405                 if (ctx_event_pending(ctx) || (ctx->status == CLOSED))
 406                         break;
 407
 408                 if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu)) {
 409                         rc = -EIO;
 410                         goto out;
 411                 }
 412
 413                 if (file->f_flags & O_NONBLOCK) {
 414                         rc = -EAGAIN;
 415                         goto out;
 416                 }
 417
 418                 if (signal_pending(current)) {
 419                         rc = -ERESTARTSYS;
 420                         goto out;
 421                 }
 422
 423                 spin_unlock_irqrestore(&ctx->lock, flags);
 424                 pr_devel("afu_read going to sleep...\n");
 425                 schedule();
 426                 pr_devel("afu_read woken up\n");
 427                 spin_lock_irqsave(&ctx->lock, flags);
 428         }
 429
 430         finish_wait(&ctx->wq, &wait);
 431
 432         memset(&event, 0, sizeof(event));
 433         event.header.process_element = ctx->pe;
 434         event.header.size = sizeof(struct cxl_event_header);
 435         if (ctx->afu_driver_ops && atomic_read(&ctx->afu_driver_events)) {
 436                 pr_devel("afu_read delivering AFU driver specific event\n");
 437                 pl = ctx->afu_driver_ops->fetch_event(ctx);
 438                 atomic_dec(&ctx->afu_driver_events);
 439                 event.header.type = CXL_EVENT_AFU_DRIVER;
 440         } else if (ctx->pending_irq) {
 441                 pr_devel("afu_read delivering AFU interrupt\n");
 442                 event.header.size += sizeof(struct cxl_event_afu_interrupt);
 443                 event.header.type = CXL_EVENT_AFU_INTERRUPT;
 444                 event.irq.irq = find_first_bit(ctx->irq_bitmap, ctx->irq_count) + 1;
 445                 clear_bit(event.irq.irq - 1, ctx->irq_bitmap);
 446                 if (bitmap_empty(ctx->irq_bitmap, ctx->irq_count))
 447                         ctx->pending_irq = false;
 448         } else if (ctx->pending_fault) {
 449                 pr_devel("afu_read delivering data storage fault\n");
 450                 event.header.size += sizeof(struct cxl_event_data_storage);
 451                 event.header.type = CXL_EVENT_DATA_STORAGE;
 452                 event.fault.addr = ctx->fault_addr;
 453                 event.fault.dsisr = ctx->fault_dsisr;
 454                 ctx->pending_fault = false;
 455         } else if (ctx->pending_afu_err) {
 456                 pr_devel("afu_read delivering afu error\n");
 457                 event.header.size += sizeof(struct cxl_event_afu_error);
 458                 event.header.type = CXL_EVENT_AFU_ERROR;
 459                 event.afu_error.error = ctx->afu_err;
 460                 ctx->pending_afu_err = false;
 461         } else if (ctx->status == CLOSED) {
 462                 pr_devel("afu_read fatal error\n");
 463                 spin_unlock_irqrestore(&ctx->lock, flags);
 464                 return -EIO;
 465         } else
 466                 WARN(1, "afu_read must be buggy\n");
 467
 468         spin_unlock_irqrestore(&ctx->lock, flags);
 469
 470         if (event.header.type == CXL_EVENT_AFU_DRIVER)
 471                 return afu_driver_event_copy(ctx, buf, &event, pl);
 472
 473         if (copy_to_user(buf, &event, event.header.size))
 474                 return -EFAULT;
 475         return event.header.size;
 476
 477 out:
 478         finish_wait(&ctx->wq, &wait);
 479         spin_unlock_irqrestore(&ctx->lock, flags);
 480         return rc;
 481 }
 482
 483 /*
 484  * Note: if this is updated, we need to update api.c to patch the new ones in
 485  * too
 486  */
 487 const struct file_operations afu_fops = {
 488         .owner          = THIS_MODULE,
 489         .open           = afu_open,
 490         .poll           = afu_poll,
 491         .read           = afu_read,
 492         .release        = afu_release,
 493         .unlocked_ioctl = afu_ioctl,
 494         .compat_ioctl   = afu_compat_ioctl,
 495         .mmap           = afu_mmap,
 496 };
 497
 498 static const struct file_operations afu_master_fops = {
 499         .owner          = THIS_MODULE,
 500         .open           = afu_master_open,
 501         .poll           = afu_poll,
 502         .read           = afu_read,
 503         .release        = afu_release,
 504         .unlocked_ioctl = afu_ioctl,
 505         .compat_ioctl   = afu_compat_ioctl,
 506         .mmap           = afu_mmap,
 507 };
 508
 509
 510 static char *cxl_devnode(struct device *dev, umode_t *mode)
 511 {
 512         if (cpu_has_feature(CPU_FTR_HVMODE) &&
 513             CXL_DEVT_IS_CARD(dev->devt)) {
 514                 /*
 515                  * These minor numbers will eventually be used to program the
 516                  * PSL and AFUs once we have dynamic reprogramming support
 517                  */
 518                 return NULL;
 519         }
 520         return kasprintf(GFP_KERNEL, "cxl/%s", dev_name(dev));
 521 }
 522
 523 extern struct class *cxl_class;
 524
 525 static int cxl_add_chardev(struct cxl_afu *afu, dev_t devt, struct cdev *cdev,
 526                            struct device **chardev, char *postfix, char *desc,
 527                            const struct file_operations *fops)
 528 {
 529         struct device *dev;
 530         int rc;
 531
 532         cdev_init(cdev, fops);
 533         if ((rc = cdev_add(cdev, devt, 1))) {
 534                 dev_err(&afu->dev, "Unable to add %s chardev: %i\n", desc, rc);
 535                 return rc;
 536         }
 537
 538         dev = device_create(cxl_class, &afu->dev, devt, afu,
 539                         "afu%i.%i%s", afu->adapter->adapter_num, afu->slice, postfix);
 540         if (IS_ERR(dev)) {
 541                 dev_err(&afu->dev, "Unable to create %s chardev in sysfs: %i\n", desc, rc);
 542                 rc = PTR_ERR(dev);
 543                 goto err;
 544         }
 545
 546         *chardev = dev;
 547
 548         return 0;
 549 err:
 550         cdev_del(cdev);
 551         return rc;
 552 }
 553
 554 int cxl_chardev_d_afu_add(struct cxl_afu *afu)
 555 {
 556         return cxl_add_chardev(afu, CXL_AFU_MKDEV_D(afu), &afu->afu_cdev_d,
 557                                &afu->chardev_d, "d", "dedicated",
 558                                &afu_master_fops); /* Uses master fops */
 559 }
 560
 561 int cxl_chardev_m_afu_add(struct cxl_afu *afu)
 562 {
 563         return cxl_add_chardev(afu, CXL_AFU_MKDEV_M(afu), &afu->afu_cdev_m,
 564                                &afu->chardev_m, "m", "master",
 565                                &afu_master_fops);
 566 }
 567
 568 int cxl_chardev_s_afu_add(struct cxl_afu *afu)
 569 {
 570         return cxl_add_chardev(afu, CXL_AFU_MKDEV_S(afu), &afu->afu_cdev_s,
 571                                &afu->chardev_s, "s", "shared",
 572                                &afu_fops);
 573 }
 574
 575 void cxl_chardev_afu_remove(struct cxl_afu *afu)
 576 {
 577         if (afu->chardev_d) {
 578                 cdev_del(&afu->afu_cdev_d);
 579                 device_unregister(afu->chardev_d);
 580                 afu->chardev_d = NULL;
 581         }
 582         if (afu->chardev_m) {
 583                 cdev_del(&afu->afu_cdev_m);
 584                 device_unregister(afu->chardev_m);
 585                 afu->chardev_m = NULL;
 586         }
 587         if (afu->chardev_s) {
 588                 cdev_del(&afu->afu_cdev_s);
 589                 device_unregister(afu->chardev_s);
 590                 afu->chardev_s = NULL;
 591         }
 592 }
 593
 594 int cxl_register_afu(struct cxl_afu *afu)
 595 {
 596         afu->dev.class = cxl_class;
 597
 598         return device_register(&afu->dev);
 599 }
 600
 601 int cxl_register_adapter(struct cxl *adapter)
 602 {
 603         adapter->dev.class = cxl_class;
 604
 605         /*
 606          * Future: When we support dynamically reprogramming the PSL & AFU we
 607          * will expose the interface to do that via a chardev:
 608          * adapter->dev.devt = CXL_CARD_MKDEV(adapter);
 609          */
 610
 611         return device_register(&adapter->dev);
 612 }
 613
 614 dev_t cxl_get_dev(void)
 615 {
 616         return cxl_dev;
 617 }
 618
 619 int __init cxl_file_init(void)
 620 {
 621         int rc;
 622
 623         /*
 624          * If these change we really need to update API.  Either change some
 625          * flags or update API version number CXL_API_VERSION.
 626          */
 627         BUILD_BUG_ON(CXL_API_VERSION != 3);
 628         BUILD_BUG_ON(sizeof(struct cxl_ioctl_start_work) != 64);
 629         BUILD_BUG_ON(sizeof(struct cxl_event_header) != 8);
 630         BUILD_BUG_ON(sizeof(struct cxl_event_afu_interrupt) != 8);
 631         BUILD_BUG_ON(sizeof(struct cxl_event_data_storage) != 32);
 632         BUILD_BUG_ON(sizeof(struct cxl_event_afu_error) != 16);
 633
 634         if ((rc = alloc_chrdev_region(&cxl_dev, 0, CXL_NUM_MINORS, "cxl"))) {
 635                 pr_err("Unable to allocate CXL major number: %i\n", rc);
 636                 return rc;
 637         }
 638
 639         pr_devel("CXL device allocated, MAJOR %i\n", MAJOR(cxl_dev));
 640
 641         cxl_class = class_create(THIS_MODULE, "cxl");
 642         if (IS_ERR(cxl_class)) {
 643                 pr_err("Unable to create CXL class\n");
 644                 rc = PTR_ERR(cxl_class);
 645                 goto err;
 646         }
 647         cxl_class->devnode = cxl_devnode;
 648
 649         return 0;
 650
 651 err:
 652         unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS);
 653         return rc;
 654 }
 655
 656 void cxl_file_exit(void)
 657 {
 658         unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS);
 659         class_destroy(cxl_class);
 660 }