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