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