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
  27 #define CXL_NUM_MINORS 256 /* Total to reserve */
  28 #define CXL_DEV_MINORS 13   /* 1 control + 4 AFUs * 3 (dedicated/master/shared) */
  29
  30 #define CXL_CARD_MINOR(adapter) (adapter->adapter_num * CXL_DEV_MINORS)
  31 #define CXL_AFU_MINOR_D(afu) (CXL_CARD_MINOR(afu->adapter) + 1 + (3 * afu->slice))
  32 #define CXL_AFU_MINOR_M(afu) (CXL_AFU_MINOR_D(afu) + 1)
  33 #define CXL_AFU_MINOR_S(afu) (CXL_AFU_MINOR_D(afu) + 2)
  34 #define CXL_AFU_MKDEV_D(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_D(afu))
  35 #define CXL_AFU_MKDEV_M(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_M(afu))
  36 #define CXL_AFU_MKDEV_S(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_S(afu))
  37
  38 #define CXL_DEVT_ADAPTER(dev) (MINOR(dev) / CXL_DEV_MINORS)
  39 #define CXL_DEVT_AFU(dev) ((MINOR(dev) % CXL_DEV_MINORS - 1) / 3)
  40
  41 #define CXL_DEVT_IS_CARD(dev) (MINOR(dev) % CXL_DEV_MINORS == 0)
  42
  43 static dev_t cxl_dev;
  44
  45 static struct class *cxl_class;
  46
  47 static int __afu_open(struct inode *inode, struct file *file, bool master)
  48 {
  49         struct cxl *adapter;
  50         struct cxl_afu *afu;
  51         struct cxl_context *ctx;
  52         int adapter_num = CXL_DEVT_ADAPTER(inode->i_rdev);
  53         int slice = CXL_DEVT_AFU(inode->i_rdev);
  54         int rc = -ENODEV;
  55
  56         pr_devel("afu_open afu%i.%i\n", slice, adapter_num);
  57
  58         if (!(adapter = get_cxl_adapter(adapter_num)))
  59                 return -ENODEV;
  60
  61         if (slice > adapter->slices)
  62                 goto err_put_adapter;
  63
  64         spin_lock(&adapter->afu_list_lock);
  65         if (!(afu = adapter->afu[slice])) {
  66                 spin_unlock(&adapter->afu_list_lock);
  67                 goto err_put_adapter;
  68         }
  69         get_device(&afu->dev);
  70         spin_unlock(&adapter->afu_list_lock);
  71
  72         if (!afu->current_mode)
  73                 goto err_put_afu;
  74
  75         if (!(ctx = cxl_context_alloc())) {
  76                 rc = -ENOMEM;
  77                 goto err_put_afu;
  78         }
  79
  80         if ((rc = cxl_context_init(ctx, afu, master)))
  81                 goto err_put_afu;
  82
  83         pr_devel("afu_open pe: %i\n", ctx->pe);
  84         file->private_data = ctx;
  85         cxl_ctx_get();
  86
  87         /* Our ref on the AFU will now hold the adapter */
  88         put_device(&adapter->dev);
  89
  90         return 0;
  91
  92 err_put_afu:
  93         put_device(&afu->dev);
  94 err_put_adapter:
  95         put_device(&adapter->dev);
  96         return rc;
  97 }
  98 static int afu_open(struct inode *inode, struct file *file)
  99 {
 100         return __afu_open(inode, file, false);
 101 }
 102
 103 static int afu_master_open(struct inode *inode, struct file *file)
 104 {
 105         return __afu_open(inode, file, true);
 106 }
 107
 108 static int afu_release(struct inode *inode, struct file *file)
 109 {
 110         struct cxl_context *ctx = file->private_data;
 111
 112         pr_devel("%s: closing cxl file descriptor. pe: %i\n",
 113                  __func__, ctx->pe);
 114         cxl_context_detach(ctx);
 115
 116         put_device(&ctx->afu->dev);
 117
 118         /*
 119          * At this this point all bottom halfs have finished and we should be
 120          * getting no more IRQs from the hardware for this context.  Once it's
 121          * removed from the IDR (and RCU synchronised) it's safe to free the
 122          * sstp and context.
 123          */
 124         cxl_context_free(ctx);
 125
 126         cxl_ctx_put();
 127         return 0;
 128 }
 129
 130 static long afu_ioctl_start_work(struct cxl_context *ctx,
 131                                  struct cxl_ioctl_start_work __user *uwork)
 132 {
 133         struct cxl_ioctl_start_work work;
 134         u64 amr = 0;
 135         int rc;
 136
 137         pr_devel("%s: pe: %i\n", __func__, ctx->pe);
 138
 139         mutex_lock(&ctx->status_mutex);
 140         if (ctx->status != OPENED) {
 141                 rc = -EIO;
 142                 goto out;
 143         }
 144
 145         if (copy_from_user(&work, uwork,
 146                            sizeof(struct cxl_ioctl_start_work))) {
 147                 rc = -EFAULT;
 148                 goto out;
 149         }
 150
 151         /*
 152          * if any of the reserved fields are set or any of the unused
 153          * flags are set it's invalid
 154          */
 155         if (work.reserved1 || work.reserved2 || work.reserved3 ||
 156             work.reserved4 || work.reserved5 || work.reserved6 ||
 157             (work.flags & ~CXL_START_WORK_ALL)) {
 158                 rc = -EINVAL;
 159                 goto out;
 160         }
 161
 162         if (!(work.flags & CXL_START_WORK_NUM_IRQS))
 163                 work.num_interrupts = ctx->afu->pp_irqs;
 164         else if ((work.num_interrupts < ctx->afu->pp_irqs) ||
 165                  (work.num_interrupts > ctx->afu->irqs_max)) {
 166                 rc =  -EINVAL;
 167                 goto out;
 168         }
 169         if ((rc = afu_register_irqs(ctx, work.num_interrupts)))
 170                 goto out;
 171
 172         if (work.flags & CXL_START_WORK_AMR)
 173                 amr = work.amr & mfspr(SPRN_UAMOR);
 174
 175         /*
 176          * We grab the PID here and not in the file open to allow for the case
 177          * where a process (master, some daemon, etc) has opened the chardev on
 178          * behalf of another process, so the AFU's mm gets bound to the process
 179          * that performs this ioctl and not the process that opened the file.
 180          */
 181         ctx->pid = get_pid(get_task_pid(current, PIDTYPE_PID));
 182
 183         if ((rc = cxl_attach_process(ctx, false, work.work_element_descriptor,
 184                                      amr)))
 185                 goto out;
 186
 187         ctx->status = STARTED;
 188         rc = 0;
 189 out:
 190         mutex_unlock(&ctx->status_mutex);
 191         return rc;
 192 }
 193 static long afu_ioctl_process_element(struct cxl_context *ctx,
 194                                       int __user *upe)
 195 {
 196         pr_devel("%s: pe: %i\n", __func__, ctx->pe);
 197
 198         if (copy_to_user(upe, &ctx->pe, sizeof(__u32)))
 199                 return -EFAULT;
 200
 201         return 0;
 202 }
 203
 204 static long afu_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 205 {
 206         struct cxl_context *ctx = file->private_data;
 207
 208         if (ctx->status == CLOSED)
 209                 return -EIO;
 210
 211         pr_devel("afu_ioctl\n");
 212         switch (cmd) {
 213         case CXL_IOCTL_START_WORK:
 214                 return afu_ioctl_start_work(ctx, (struct cxl_ioctl_start_work __user *)arg);
 215         case CXL_IOCTL_GET_PROCESS_ELEMENT:
 216                 return afu_ioctl_process_element(ctx, (__u32 __user *)arg);
 217         }
 218         return -EINVAL;
 219 }
 220
 221 static long afu_compat_ioctl(struct file *file, unsigned int cmd,
 222                              unsigned long arg)
 223 {
 224         return afu_ioctl(file, cmd, arg);
 225 }
 226
 227 static int afu_mmap(struct file *file, struct vm_area_struct *vm)
 228 {
 229         struct cxl_context *ctx = file->private_data;
 230
 231         /* AFU must be started before we can MMIO */
 232         if (ctx->status != STARTED)
 233                 return -EIO;
 234
 235         return cxl_context_iomap(ctx, vm);
 236 }
 237
 238 static unsigned int afu_poll(struct file *file, struct poll_table_struct *poll)
 239 {
 240         struct cxl_context *ctx = file->private_data;
 241         int mask = 0;
 242         unsigned long flags;
 243
 244
 245         poll_wait(file, &ctx->wq, poll);
 246
 247         pr_devel("afu_poll wait done pe: %i\n", ctx->pe);
 248
 249         spin_lock_irqsave(&ctx->lock, flags);
 250         if (ctx->pending_irq || ctx->pending_fault ||
 251             ctx->pending_afu_err)
 252                 mask |= POLLIN | POLLRDNORM;
 253         else if (ctx->status == CLOSED)
 254                 /* Only error on closed when there are no futher events pending
 255                  */
 256                 mask |= POLLERR;
 257         spin_unlock_irqrestore(&ctx->lock, flags);
 258
 259         pr_devel("afu_poll pe: %i returning %#x\n", ctx->pe, mask);
 260
 261         return mask;
 262 }
 263
 264 static inline int ctx_event_pending(struct cxl_context *ctx)
 265 {
 266         return (ctx->pending_irq || ctx->pending_fault ||
 267             ctx->pending_afu_err || (ctx->status == CLOSED));
 268 }
 269
 270 static ssize_t afu_read(struct file *file, char __user *buf, size_t count,
 271                         loff_t *off)
 272 {
 273         struct cxl_context *ctx = file->private_data;
 274         struct cxl_event event;
 275         unsigned long flags;
 276         int rc;
 277         DEFINE_WAIT(wait);
 278
 279         if (count < CXL_READ_MIN_SIZE)
 280                 return -EINVAL;
 281
 282         spin_lock_irqsave(&ctx->lock, flags);
 283
 284         for (;;) {
 285                 prepare_to_wait(&ctx->wq, &wait, TASK_INTERRUPTIBLE);
 286                 if (ctx_event_pending(ctx))
 287                         break;
 288
 289                 if (file->f_flags & O_NONBLOCK) {
 290                         rc = -EAGAIN;
 291                         goto out;
 292                 }
 293
 294                 if (signal_pending(current)) {
 295                         rc = -ERESTARTSYS;
 296                         goto out;
 297                 }
 298
 299                 spin_unlock_irqrestore(&ctx->lock, flags);
 300                 pr_devel("afu_read going to sleep...\n");
 301                 schedule();
 302                 pr_devel("afu_read woken up\n");
 303                 spin_lock_irqsave(&ctx->lock, flags);
 304         }
 305
 306         finish_wait(&ctx->wq, &wait);
 307
 308         memset(&event, 0, sizeof(event));
 309         event.header.process_element = ctx->pe;
 310         event.header.size = sizeof(struct cxl_event_header);
 311         if (ctx->pending_irq) {
 312                 pr_devel("afu_read delivering AFU interrupt\n");
 313                 event.header.size += sizeof(struct cxl_event_afu_interrupt);
 314                 event.header.type = CXL_EVENT_AFU_INTERRUPT;
 315                 event.irq.irq = find_first_bit(ctx->irq_bitmap, ctx->irq_count) + 1;
 316                 clear_bit(event.irq.irq - 1, ctx->irq_bitmap);
 317                 if (bitmap_empty(ctx->irq_bitmap, ctx->irq_count))
 318                         ctx->pending_irq = false;
 319         } else if (ctx->pending_fault) {
 320                 pr_devel("afu_read delivering data storage fault\n");
 321                 event.header.size += sizeof(struct cxl_event_data_storage);
 322                 event.header.type = CXL_EVENT_DATA_STORAGE;
 323                 event.fault.addr = ctx->fault_addr;
 324                 event.fault.dsisr = ctx->fault_dsisr;
 325                 ctx->pending_fault = false;
 326         } else if (ctx->pending_afu_err) {
 327                 pr_devel("afu_read delivering afu error\n");
 328                 event.header.size += sizeof(struct cxl_event_afu_error);
 329                 event.header.type = CXL_EVENT_AFU_ERROR;
 330                 event.afu_error.error = ctx->afu_err;
 331                 ctx->pending_afu_err = false;
 332         } else if (ctx->status == CLOSED) {
 333                 pr_devel("afu_read fatal error\n");
 334                 spin_unlock_irqrestore(&ctx->lock, flags);
 335                 return -EIO;
 336         } else
 337                 WARN(1, "afu_read must be buggy\n");
 338
 339         spin_unlock_irqrestore(&ctx->lock, flags);
 340
 341         if (copy_to_user(buf, &event, event.header.size))
 342                 return -EFAULT;
 343         return event.header.size;
 344
 345 out:
 346         finish_wait(&ctx->wq, &wait);
 347         spin_unlock_irqrestore(&ctx->lock, flags);
 348         return rc;
 349 }
 350
 351 static const struct file_operations afu_fops = {
 352         .owner          = THIS_MODULE,
 353         .open           = afu_open,
 354         .poll           = afu_poll,
 355         .read           = afu_read,
 356         .release        = afu_release,
 357         .unlocked_ioctl = afu_ioctl,
 358         .compat_ioctl   = afu_compat_ioctl,
 359         .mmap           = afu_mmap,
 360 };
 361
 362 static const struct file_operations afu_master_fops = {
 363         .owner          = THIS_MODULE,
 364         .open           = afu_master_open,
 365         .poll           = afu_poll,
 366         .read           = afu_read,
 367         .release        = afu_release,
 368         .unlocked_ioctl = afu_ioctl,
 369         .compat_ioctl   = afu_compat_ioctl,
 370         .mmap           = afu_mmap,
 371 };
 372
 373
 374 static char *cxl_devnode(struct device *dev, umode_t *mode)
 375 {
 376         if (CXL_DEVT_IS_CARD(dev->devt)) {
 377                 /*
 378                  * These minor numbers will eventually be used to program the
 379                  * PSL and AFUs once we have dynamic reprogramming support
 380                  */
 381                 return NULL;
 382         }
 383         return kasprintf(GFP_KERNEL, "cxl/%s", dev_name(dev));
 384 }
 385
 386 extern struct class *cxl_class;
 387
 388 static int cxl_add_chardev(struct cxl_afu *afu, dev_t devt, struct cdev *cdev,
 389                            struct device **chardev, char *postfix, char *desc,
 390                            const struct file_operations *fops)
 391 {
 392         struct device *dev;
 393         int rc;
 394
 395         cdev_init(cdev, fops);
 396         if ((rc = cdev_add(cdev, devt, 1))) {
 397                 dev_err(&afu->dev, "Unable to add %s chardev: %i\n", desc, rc);
 398                 return rc;
 399         }
 400
 401         dev = device_create(cxl_class, &afu->dev, devt, afu,
 402                         "afu%i.%i%s", afu->adapter->adapter_num, afu->slice, postfix);
 403         if (IS_ERR(dev)) {
 404                 dev_err(&afu->dev, "Unable to create %s chardev in sysfs: %i\n", desc, rc);
 405                 rc = PTR_ERR(dev);
 406                 goto err;
 407         }
 408
 409         *chardev = dev;
 410
 411         return 0;
 412 err:
 413         cdev_del(cdev);
 414         return rc;
 415 }
 416
 417 int cxl_chardev_d_afu_add(struct cxl_afu *afu)
 418 {
 419         return cxl_add_chardev(afu, CXL_AFU_MKDEV_D(afu), &afu->afu_cdev_d,
 420                                &afu->chardev_d, "d", "dedicated",
 421                                &afu_master_fops); /* Uses master fops */
 422 }
 423
 424 int cxl_chardev_m_afu_add(struct cxl_afu *afu)
 425 {
 426         return cxl_add_chardev(afu, CXL_AFU_MKDEV_M(afu), &afu->afu_cdev_m,
 427                                &afu->chardev_m, "m", "master",
 428                                &afu_master_fops);
 429 }
 430
 431 int cxl_chardev_s_afu_add(struct cxl_afu *afu)
 432 {
 433         return cxl_add_chardev(afu, CXL_AFU_MKDEV_S(afu), &afu->afu_cdev_s,
 434                                &afu->chardev_s, "s", "shared",
 435                                &afu_fops);
 436 }
 437
 438 void cxl_chardev_afu_remove(struct cxl_afu *afu)
 439 {
 440         if (afu->chardev_d) {
 441                 cdev_del(&afu->afu_cdev_d);
 442                 device_unregister(afu->chardev_d);
 443                 afu->chardev_d = NULL;
 444         }
 445         if (afu->chardev_m) {
 446                 cdev_del(&afu->afu_cdev_m);
 447                 device_unregister(afu->chardev_m);
 448                 afu->chardev_m = NULL;
 449         }
 450         if (afu->chardev_s) {
 451                 cdev_del(&afu->afu_cdev_s);
 452                 device_unregister(afu->chardev_s);
 453                 afu->chardev_s = NULL;
 454         }
 455 }
 456
 457 int cxl_register_afu(struct cxl_afu *afu)
 458 {
 459         afu->dev.class = cxl_class;
 460
 461         return device_register(&afu->dev);
 462 }
 463
 464 int cxl_register_adapter(struct cxl *adapter)
 465 {
 466         adapter->dev.class = cxl_class;
 467
 468         /*
 469          * Future: When we support dynamically reprogramming the PSL & AFU we
 470          * will expose the interface to do that via a chardev:
 471          * adapter->dev.devt = CXL_CARD_MKDEV(adapter);
 472          */
 473
 474         return device_register(&adapter->dev);
 475 }
 476
 477 int __init cxl_file_init(void)
 478 {
 479         int rc;
 480
 481         /*
 482          * If these change we really need to update API.  Either change some
 483          * flags or update API version number CXL_API_VERSION.
 484          */
 485         BUILD_BUG_ON(CXL_API_VERSION != 1);
 486         BUILD_BUG_ON(sizeof(struct cxl_ioctl_start_work) != 64);
 487         BUILD_BUG_ON(sizeof(struct cxl_event_header) != 8);
 488         BUILD_BUG_ON(sizeof(struct cxl_event_afu_interrupt) != 8);
 489         BUILD_BUG_ON(sizeof(struct cxl_event_data_storage) != 32);
 490         BUILD_BUG_ON(sizeof(struct cxl_event_afu_error) != 16);
 491
 492         if ((rc = alloc_chrdev_region(&cxl_dev, 0, CXL_NUM_MINORS, "cxl"))) {
 493                 pr_err("Unable to allocate CXL major number: %i\n", rc);
 494                 return rc;
 495         }
 496
 497         pr_devel("CXL device allocated, MAJOR %i\n", MAJOR(cxl_dev));
 498
 499         cxl_class = class_create(THIS_MODULE, "cxl");
 500         if (IS_ERR(cxl_class)) {
 501                 pr_err("Unable to create CXL class\n");
 502                 rc = PTR_ERR(cxl_class);
 503                 goto err;
 504         }
 505         cxl_class->devnode = cxl_devnode;
 506
 507         return 0;
 508
 509 err:
 510         unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS);
 511         return rc;
 512 }
 513
 514 void cxl_file_exit(void)
 515 {
 516         unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS);
 517         class_destroy(cxl_class);
 518 }