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