drivers/mtd/mtdchar.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
   4  */
   5
   6 #include <linux/device.h>
   7 #include <linux/fs.h>
   8 #include <linux/mm.h>
   9 #include <linux/err.h>
  10 #include <linux/init.h>
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/sched.h>
  15 #include <linux/mutex.h>
  16 #include <linux/backing-dev.h>
  17 #include <linux/compat.h>
  18 #include <linux/mount.h>
  19 #include <linux/blkpg.h>
  20 #include <linux/magic.h>
  21 #include <linux/major.h>
  22 #include <linux/mtd/mtd.h>
  23 #include <linux/mtd/partitions.h>
  24 #include <linux/mtd/map.h>
  25
  26 #include <linux/uaccess.h>
  27
  28 #include "mtdcore.h"
  29
  30 /*
  31  * Data structure to hold the pointer to the mtd device as well
  32  * as mode information of various use cases.
  33  */
  34 struct mtd_file_info {
  35         struct mtd_info *mtd;
  36         enum mtd_file_modes mode;
  37 };
  38
  39 static loff_t mtdchar_lseek(struct file *file, loff_t offset, int orig)
  40 {
  41         struct mtd_file_info *mfi = file->private_data;
  42         return fixed_size_llseek(file, offset, orig, mfi->mtd->size);
  43 }
  44
  45 static int mtdchar_open(struct inode *inode, struct file *file)
  46 {
  47         int minor = iminor(inode);
  48         int devnum = minor >> 1;
  49         int ret = 0;
  50         struct mtd_info *mtd;
  51         struct mtd_file_info *mfi;
  52
  53         pr_debug("MTD_open\n");
  54
  55         /* You can't open the RO devices RW */
  56         if ((file->f_mode & FMODE_WRITE) && (minor & 1))
  57                 return -EACCES;
  58
  59         mtd = get_mtd_device(NULL, devnum);
  60
  61         if (IS_ERR(mtd))
  62                 return PTR_ERR(mtd);
  63
  64         if (mtd->type == MTD_ABSENT) {
  65                 ret = -ENODEV;
  66                 goto out1;
  67         }
  68
  69         /* You can't open it RW if it's not a writeable device */
  70         if ((file->f_mode & FMODE_WRITE) && !(mtd->flags & MTD_WRITEABLE)) {
  71                 ret = -EACCES;
  72                 goto out1;
  73         }
  74
  75         mfi = kzalloc(sizeof(*mfi), GFP_KERNEL);
  76         if (!mfi) {
  77                 ret = -ENOMEM;
  78                 goto out1;
  79         }
  80         mfi->mtd = mtd;
  81         file->private_data = mfi;
  82         return 0;
  83
  84 out1:
  85         put_mtd_device(mtd);
  86         return ret;
  87 } /* mtdchar_open */
  88
  89 /*====================================================================*/
  90
  91 static int mtdchar_close(struct inode *inode, struct file *file)
  92 {
  93         struct mtd_file_info *mfi = file->private_data;
  94         struct mtd_info *mtd = mfi->mtd;
  95
  96         pr_debug("MTD_close\n");
  97
  98         /* Only sync if opened RW */
  99         if ((file->f_mode & FMODE_WRITE))
 100                 mtd_sync(mtd);
 101
 102         put_mtd_device(mtd);
 103         file->private_data = NULL;
 104         kfree(mfi);
 105
 106         return 0;
 107 } /* mtdchar_close */
 108
 109 /* Back in June 2001, dwmw2 wrote:
 110  *
 111  *   FIXME: This _really_ needs to die. In 2.5, we should lock the
 112  *   userspace buffer down and use it directly with readv/writev.
 113  *
 114  * The implementation below, using mtd_kmalloc_up_to, mitigates
 115  * allocation failures when the system is under low-memory situations
 116  * or if memory is highly fragmented at the cost of reducing the
 117  * performance of the requested transfer due to a smaller buffer size.
 118  *
 119  * A more complex but more memory-efficient implementation based on
 120  * get_user_pages and iovecs to cover extents of those pages is a
 121  * longer-term goal, as intimated by dwmw2 above. However, for the
 122  * write case, this requires yet more complex head and tail transfer
 123  * handling when those head and tail offsets and sizes are such that
 124  * alignment requirements are not met in the NAND subdriver.
 125  */
 126
 127 static ssize_t mtdchar_read(struct file *file, char __user *buf, size_t count,
 128                         loff_t *ppos)
 129 {
 130         struct mtd_file_info *mfi = file->private_data;
 131         struct mtd_info *mtd = mfi->mtd;
 132         size_t retlen;
 133         size_t total_retlen=0;
 134         int ret=0;
 135         int len;
 136         size_t size = count;
 137         char *kbuf;
 138
 139         pr_debug("MTD_read\n");
 140
 141         if (*ppos + count > mtd->size) {
 142                 if (*ppos < mtd->size)
 143                         count = mtd->size - *ppos;
 144                 else
 145                         count = 0;
 146         }
 147
 148         if (!count)
 149                 return 0;
 150
 151         kbuf = mtd_kmalloc_up_to(mtd, &size);
 152         if (!kbuf)
 153                 return -ENOMEM;
 154
 155         while (count) {
 156                 len = min_t(size_t, count, size);
 157
 158                 switch (mfi->mode) {
 159                 case MTD_FILE_MODE_OTP_FACTORY:
 160                         ret = mtd_read_fact_prot_reg(mtd, *ppos, len,
 161                                                      &retlen, kbuf);
 162                         break;
 163                 case MTD_FILE_MODE_OTP_USER:
 164                         ret = mtd_read_user_prot_reg(mtd, *ppos, len,
 165                                                      &retlen, kbuf);
 166                         break;
 167                 case MTD_FILE_MODE_RAW:
 168                 {
 169                         struct mtd_oob_ops ops = {};
 170
 171                         ops.mode = MTD_OPS_RAW;
 172                         ops.datbuf = kbuf;
 173                         ops.oobbuf = NULL;
 174                         ops.len = len;
 175
 176                         ret = mtd_read_oob(mtd, *ppos, &ops);
 177                         retlen = ops.retlen;
 178                         break;
 179                 }
 180                 default:
 181                         ret = mtd_read(mtd, *ppos, len, &retlen, kbuf);
 182                 }
 183                 /* Nand returns -EBADMSG on ECC errors, but it returns
 184                  * the data. For our userspace tools it is important
 185                  * to dump areas with ECC errors!
 186                  * For kernel internal usage it also might return -EUCLEAN
 187                  * to signal the caller that a bitflip has occurred and has
 188                  * been corrected by the ECC algorithm.
 189                  * Userspace software which accesses NAND this way
 190                  * must be aware of the fact that it deals with NAND
 191                  */
 192                 if (!ret || mtd_is_bitflip_or_eccerr(ret)) {
 193                         *ppos += retlen;
 194                         if (copy_to_user(buf, kbuf, retlen)) {
 195                                 kfree(kbuf);
 196                                 return -EFAULT;
 197                         }
 198                         else
 199                                 total_retlen += retlen;
 200
 201                         count -= retlen;
 202                         buf += retlen;
 203                         if (retlen == 0)
 204                                 count = 0;
 205                 }
 206                 else {
 207                         kfree(kbuf);
 208                         return ret;
 209                 }
 210
 211         }
 212
 213         kfree(kbuf);
 214         return total_retlen;
 215 } /* mtdchar_read */
 216
 217 static ssize_t mtdchar_write(struct file *file, const char __user *buf, size_t count,
 218                         loff_t *ppos)
 219 {
 220         struct mtd_file_info *mfi = file->private_data;
 221         struct mtd_info *mtd = mfi->mtd;
 222         size_t size = count;
 223         char *kbuf;
 224         size_t retlen;
 225         size_t total_retlen=0;
 226         int ret=0;
 227         int len;
 228
 229         pr_debug("MTD_write\n");
 230
 231         if (*ppos >= mtd->size)
 232                 return -ENOSPC;
 233
 234         if (*ppos + count > mtd->size)
 235                 count = mtd->size - *ppos;
 236
 237         if (!count)
 238                 return 0;
 239
 240         kbuf = mtd_kmalloc_up_to(mtd, &size);
 241         if (!kbuf)
 242                 return -ENOMEM;
 243
 244         while (count) {
 245                 len = min_t(size_t, count, size);
 246
 247                 if (copy_from_user(kbuf, buf, len)) {
 248                         kfree(kbuf);
 249                         return -EFAULT;
 250                 }
 251
 252                 switch (mfi->mode) {
 253                 case MTD_FILE_MODE_OTP_FACTORY:
 254                         ret = -EROFS;
 255                         break;
 256                 case MTD_FILE_MODE_OTP_USER:
 257                         ret = mtd_write_user_prot_reg(mtd, *ppos, len,
 258                                                       &retlen, kbuf);
 259                         break;
 260
 261                 case MTD_FILE_MODE_RAW:
 262                 {
 263                         struct mtd_oob_ops ops = {};
 264
 265                         ops.mode = MTD_OPS_RAW;
 266                         ops.datbuf = kbuf;
 267                         ops.oobbuf = NULL;
 268                         ops.ooboffs = 0;
 269                         ops.len = len;
 270
 271                         ret = mtd_write_oob(mtd, *ppos, &ops);
 272                         retlen = ops.retlen;
 273                         break;
 274                 }
 275
 276                 default:
 277                         ret = mtd_write(mtd, *ppos, len, &retlen, kbuf);
 278                 }
 279
 280                 /*
 281                  * Return -ENOSPC only if no data could be written at all.
 282                  * Otherwise just return the number of bytes that actually
 283                  * have been written.
 284                  */
 285                 if ((ret == -ENOSPC) && (total_retlen))
 286                         break;
 287
 288                 if (!ret) {
 289                         *ppos += retlen;
 290                         total_retlen += retlen;
 291                         count -= retlen;
 292                         buf += retlen;
 293                 }
 294                 else {
 295                         kfree(kbuf);
 296                         return ret;
 297                 }
 298         }
 299
 300         kfree(kbuf);
 301         return total_retlen;
 302 } /* mtdchar_write */
 303
 304 /*======================================================================
 305
 306     IOCTL calls for getting device parameters.
 307
 308 ======================================================================*/
 309
 310 static int otp_select_filemode(struct mtd_file_info *mfi, int mode)
 311 {
 312         struct mtd_info *mtd = mfi->mtd;
 313         size_t retlen;
 314
 315         switch (mode) {
 316         case MTD_OTP_FACTORY:
 317                 if (mtd_read_fact_prot_reg(mtd, -1, 0, &retlen, NULL) ==
 318                                 -EOPNOTSUPP)
 319                         return -EOPNOTSUPP;
 320
 321                 mfi->mode = MTD_FILE_MODE_OTP_FACTORY;
 322                 break;
 323         case MTD_OTP_USER:
 324                 if (mtd_read_user_prot_reg(mtd, -1, 0, &retlen, NULL) ==
 325                                 -EOPNOTSUPP)
 326                         return -EOPNOTSUPP;
 327
 328                 mfi->mode = MTD_FILE_MODE_OTP_USER;
 329                 break;
 330         case MTD_OTP_OFF:
 331                 mfi->mode = MTD_FILE_MODE_NORMAL;
 332                 break;
 333         default:
 334                 return -EINVAL;
 335         }
 336
 337         return 0;
 338 }
 339
 340 static int mtdchar_writeoob(struct file *file, struct mtd_info *mtd,
 341         uint64_t start, uint32_t length, void __user *ptr,
 342         uint32_t __user *retp)
 343 {
 344         struct mtd_info *master  = mtd_get_master(mtd);
 345         struct mtd_file_info *mfi = file->private_data;
 346         struct mtd_oob_ops ops = {};
 347         uint32_t retlen;
 348         int ret = 0;
 349
 350         if (length > 4096)
 351                 return -EINVAL;
 352
 353         if (!master->_write_oob)
 354                 return -EOPNOTSUPP;
 355
 356         ops.ooblen = length;
 357         ops.ooboffs = start & (mtd->writesize - 1);
 358         ops.datbuf = NULL;
 359         ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
 360                 MTD_OPS_PLACE_OOB;
 361
 362         if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
 363                 return -EINVAL;
 364
 365         ops.oobbuf = memdup_user(ptr, length);
 366         if (IS_ERR(ops.oobbuf))
 367                 return PTR_ERR(ops.oobbuf);
 368
 369         start &= ~((uint64_t)mtd->writesize - 1);
 370         ret = mtd_write_oob(mtd, start, &ops);
 371
 372         if (ops.oobretlen > 0xFFFFFFFFU)
 373                 ret = -EOVERFLOW;
 374         retlen = ops.oobretlen;
 375         if (copy_to_user(retp, &retlen, sizeof(length)))
 376                 ret = -EFAULT;
 377
 378         kfree(ops.oobbuf);
 379         return ret;
 380 }
 381
 382 static int mtdchar_readoob(struct file *file, struct mtd_info *mtd,
 383         uint64_t start, uint32_t length, void __user *ptr,
 384         uint32_t __user *retp)
 385 {
 386         struct mtd_file_info *mfi = file->private_data;
 387         struct mtd_oob_ops ops = {};
 388         int ret = 0;
 389
 390         if (length > 4096)
 391                 return -EINVAL;
 392
 393         ops.ooblen = length;
 394         ops.ooboffs = start & (mtd->writesize - 1);
 395         ops.datbuf = NULL;
 396         ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
 397                 MTD_OPS_PLACE_OOB;
 398
 399         if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
 400                 return -EINVAL;
 401
 402         ops.oobbuf = kmalloc(length, GFP_KERNEL);
 403         if (!ops.oobbuf)
 404                 return -ENOMEM;
 405
 406         start &= ~((uint64_t)mtd->writesize - 1);
 407         ret = mtd_read_oob(mtd, start, &ops);
 408
 409         if (put_user(ops.oobretlen, retp))
 410                 ret = -EFAULT;
 411         else if (ops.oobretlen && copy_to_user(ptr, ops.oobbuf,
 412                                             ops.oobretlen))
 413                 ret = -EFAULT;
 414
 415         kfree(ops.oobbuf);
 416
 417         /*
 418          * NAND returns -EBADMSG on ECC errors, but it returns the OOB
 419          * data. For our userspace tools it is important to dump areas
 420          * with ECC errors!
 421          * For kernel internal usage it also might return -EUCLEAN
 422          * to signal the caller that a bitflip has occurred and has
 423          * been corrected by the ECC algorithm.
 424          *
 425          * Note: currently the standard NAND function, nand_read_oob_std,
 426          * does not calculate ECC for the OOB area, so do not rely on
 427          * this behavior unless you have replaced it with your own.
 428          */
 429         if (mtd_is_bitflip_or_eccerr(ret))
 430                 return 0;
 431
 432         return ret;
 433 }
 434
 435 /*
 436  * Copies (and truncates, if necessary) OOB layout information to the
 437  * deprecated layout struct, nand_ecclayout_user. This is necessary only to
 438  * support the deprecated API ioctl ECCGETLAYOUT while allowing all new
 439  * functionality to use mtd_ooblayout_ops flexibly (i.e. mtd_ooblayout_ops
 440  * can describe any kind of OOB layout with almost zero overhead from a
 441  * memory usage point of view).
 442  */
 443 static int shrink_ecclayout(struct mtd_info *mtd,
 444                             struct nand_ecclayout_user *to)
 445 {
 446         struct mtd_oob_region oobregion;
 447         int i, section = 0, ret;
 448
 449         if (!mtd || !to)
 450                 return -EINVAL;
 451
 452         memset(to, 0, sizeof(*to));
 453
 454         to->eccbytes = 0;
 455         for (i = 0; i < MTD_MAX_ECCPOS_ENTRIES;) {
 456                 u32 eccpos;
 457
 458                 ret = mtd_ooblayout_ecc(mtd, section++, &oobregion);
 459                 if (ret < 0) {
 460                         if (ret != -ERANGE)
 461                                 return ret;
 462
 463                         break;
 464                 }
 465
 466                 eccpos = oobregion.offset;
 467                 for (; i < MTD_MAX_ECCPOS_ENTRIES &&
 468                        eccpos < oobregion.offset + oobregion.length; i++) {
 469                         to->eccpos[i] = eccpos++;
 470                         to->eccbytes++;
 471                 }
 472         }
 473
 474         for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES; i++) {
 475                 ret = mtd_ooblayout_free(mtd, i, &oobregion);
 476                 if (ret < 0) {
 477                         if (ret != -ERANGE)
 478                                 return ret;
 479
 480                         break;
 481                 }
 482
 483                 to->oobfree[i].offset = oobregion.offset;
 484                 to->oobfree[i].length = oobregion.length;
 485                 to->oobavail += to->oobfree[i].length;
 486         }
 487
 488         return 0;
 489 }
 490
 491 static int get_oobinfo(struct mtd_info *mtd, struct nand_oobinfo *to)
 492 {
 493         struct mtd_oob_region oobregion;
 494         int i, section = 0, ret;
 495
 496         if (!mtd || !to)
 497                 return -EINVAL;
 498
 499         memset(to, 0, sizeof(*to));
 500
 501         to->eccbytes = 0;
 502         for (i = 0; i < ARRAY_SIZE(to->eccpos);) {
 503                 u32 eccpos;
 504
 505                 ret = mtd_ooblayout_ecc(mtd, section++, &oobregion);
 506                 if (ret < 0) {
 507                         if (ret != -ERANGE)
 508                                 return ret;
 509
 510                         break;
 511                 }
 512
 513                 if (oobregion.length + i > ARRAY_SIZE(to->eccpos))
 514                         return -EINVAL;
 515
 516                 eccpos = oobregion.offset;
 517                 for (; eccpos < oobregion.offset + oobregion.length; i++) {
 518                         to->eccpos[i] = eccpos++;
 519                         to->eccbytes++;
 520                 }
 521         }
 522
 523         for (i = 0; i < 8; i++) {
 524                 ret = mtd_ooblayout_free(mtd, i, &oobregion);
 525                 if (ret < 0) {
 526                         if (ret != -ERANGE)
 527                                 return ret;
 528
 529                         break;
 530                 }
 531
 532                 to->oobfree[i][0] = oobregion.offset;
 533                 to->oobfree[i][1] = oobregion.length;
 534         }
 535
 536         to->useecc = MTD_NANDECC_AUTOPLACE;
 537
 538         return 0;
 539 }
 540
 541 static int mtdchar_blkpg_ioctl(struct mtd_info *mtd,
 542                                struct blkpg_ioctl_arg *arg)
 543 {
 544         struct blkpg_partition p;
 545
 546         if (!capable(CAP_SYS_ADMIN))
 547                 return -EPERM;
 548
 549         if (copy_from_user(&p, arg->data, sizeof(p)))
 550                 return -EFAULT;
 551
 552         switch (arg->op) {
 553         case BLKPG_ADD_PARTITION:
 554
 555                 /* Only master mtd device must be used to add partitions */
 556                 if (mtd_is_partition(mtd))
 557                         return -EINVAL;
 558
 559                 /* Sanitize user input */
 560                 p.devname[BLKPG_DEVNAMELTH - 1] = '\0';
 561
 562                 return mtd_add_partition(mtd, p.devname, p.start, p.length);
 563
 564         case BLKPG_DEL_PARTITION:
 565
 566                 if (p.pno < 0)
 567                         return -EINVAL;
 568
 569                 return mtd_del_partition(mtd, p.pno);
 570
 571         default:
 572                 return -EINVAL;
 573         }
 574 }
 575
 576 static void adjust_oob_length(struct mtd_info *mtd, uint64_t start,
 577                               struct mtd_oob_ops *ops)
 578 {
 579         uint32_t start_page, end_page;
 580         u32 oob_per_page;
 581
 582         if (ops->len == 0 || ops->ooblen == 0)
 583                 return;
 584
 585         start_page = mtd_div_by_ws(start, mtd);
 586         end_page = mtd_div_by_ws(start + ops->len - 1, mtd);
 587         oob_per_page = mtd_oobavail(mtd, ops);
 588
 589         ops->ooblen = min_t(size_t, ops->ooblen,
 590                             (end_page - start_page + 1) * oob_per_page);
 591 }
 592
 593 static noinline_for_stack int
 594 mtdchar_write_ioctl(struct mtd_info *mtd, struct mtd_write_req __user *argp)
 595 {
 596         struct mtd_info *master = mtd_get_master(mtd);
 597         struct mtd_write_req req;
 598         const void __user *usr_data, *usr_oob;
 599         uint8_t *datbuf = NULL, *oobbuf = NULL;
 600         size_t datbuf_len, oobbuf_len;
 601         int ret = 0;
 602
 603         if (copy_from_user(&req, argp, sizeof(req)))
 604                 return -EFAULT;
 605
 606         usr_data = (const void __user *)(uintptr_t)req.usr_data;
 607         usr_oob = (const void __user *)(uintptr_t)req.usr_oob;
 608
 609         if (!master->_write_oob)
 610                 return -EOPNOTSUPP;
 611
 612         if (!usr_data)
 613                 req.len = 0;
 614
 615         if (!usr_oob)
 616                 req.ooblen = 0;
 617
 618         req.len &= 0xffffffff;
 619         req.ooblen &= 0xffffffff;
 620
 621         if (req.start + req.len > mtd->size)
 622                 return -EINVAL;
 623
 624         datbuf_len = min_t(size_t, req.len, mtd->erasesize);
 625         if (datbuf_len > 0) {
 626                 datbuf = kvmalloc(datbuf_len, GFP_KERNEL);
 627                 if (!datbuf)
 628                         return -ENOMEM;
 629         }
 630
 631         oobbuf_len = min_t(size_t, req.ooblen, mtd->erasesize);
 632         if (oobbuf_len > 0) {
 633                 oobbuf = kvmalloc(oobbuf_len, GFP_KERNEL);
 634                 if (!oobbuf) {
 635                         kvfree(datbuf);
 636                         return -ENOMEM;
 637                 }
 638         }
 639
 640         while (req.len > 0 || (!usr_data && req.ooblen > 0)) {
 641                 struct mtd_oob_ops ops = {
 642                         .mode = req.mode,
 643                         .len = min_t(size_t, req.len, datbuf_len),
 644                         .ooblen = min_t(size_t, req.ooblen, oobbuf_len),
 645                         .datbuf = datbuf,
 646                         .oobbuf = oobbuf,
 647                 };
 648
 649                 /*
 650                  * Shorten non-page-aligned, eraseblock-sized writes so that
 651                  * the write ends on an eraseblock boundary.  This is necessary
 652                  * for adjust_oob_length() to properly handle non-page-aligned
 653                  * writes.
 654                  */
 655                 if (ops.len == mtd->erasesize)
 656                         ops.len -= mtd_mod_by_ws(req.start + ops.len, mtd);
 657
 658                 /*
 659                  * For writes which are not OOB-only, adjust the amount of OOB
 660                  * data written according to the number of data pages written.
 661                  * This is necessary to prevent OOB data from being skipped
 662                  * over in data+OOB writes requiring multiple mtd_write_oob()
 663                  * calls to be completed.
 664                  */
 665                 adjust_oob_length(mtd, req.start, &ops);
 666
 667                 if (copy_from_user(datbuf, usr_data, ops.len) ||
 668                     copy_from_user(oobbuf, usr_oob, ops.ooblen)) {
 669                         ret = -EFAULT;
 670                         break;
 671                 }
 672
 673                 ret = mtd_write_oob(mtd, req.start, &ops);
 674                 if (ret)
 675                         break;
 676
 677                 req.start += ops.retlen;
 678                 req.len -= ops.retlen;
 679                 usr_data += ops.retlen;
 680
 681                 req.ooblen -= ops.oobretlen;
 682                 usr_oob += ops.oobretlen;
 683         }
 684
 685         kvfree(datbuf);
 686         kvfree(oobbuf);
 687
 688         return ret;
 689 }
 690
 691 static noinline_for_stack int
 692 mtdchar_read_ioctl(struct mtd_info *mtd, struct mtd_read_req __user *argp)
 693 {
 694         struct mtd_info *master = mtd_get_master(mtd);
 695         struct mtd_read_req req;
 696         void __user *usr_data, *usr_oob;
 697         uint8_t *datbuf = NULL, *oobbuf = NULL;
 698         size_t datbuf_len, oobbuf_len;
 699         size_t orig_len, orig_ooblen;
 700         int ret = 0;
 701
 702         if (copy_from_user(&req, argp, sizeof(req)))
 703                 return -EFAULT;
 704
 705         orig_len = req.len;
 706         orig_ooblen = req.ooblen;
 707
 708         usr_data = (void __user *)(uintptr_t)req.usr_data;
 709         usr_oob = (void __user *)(uintptr_t)req.usr_oob;
 710
 711         if (!master->_read_oob)
 712                 return -EOPNOTSUPP;
 713
 714         if (!usr_data)
 715                 req.len = 0;
 716
 717         if (!usr_oob)
 718                 req.ooblen = 0;
 719
 720         req.ecc_stats.uncorrectable_errors = 0;
 721         req.ecc_stats.corrected_bitflips = 0;
 722         req.ecc_stats.max_bitflips = 0;
 723
 724         req.len &= 0xffffffff;
 725         req.ooblen &= 0xffffffff;
 726
 727         if (req.start + req.len > mtd->size) {
 728                 ret = -EINVAL;
 729                 goto out;
 730         }
 731
 732         datbuf_len = min_t(size_t, req.len, mtd->erasesize);
 733         if (datbuf_len > 0) {
 734                 datbuf = kvmalloc(datbuf_len, GFP_KERNEL);
 735                 if (!datbuf) {
 736                         ret = -ENOMEM;
 737                         goto out;
 738                 }
 739         }
 740
 741         oobbuf_len = min_t(size_t, req.ooblen, mtd->erasesize);
 742         if (oobbuf_len > 0) {
 743                 oobbuf = kvmalloc(oobbuf_len, GFP_KERNEL);
 744                 if (!oobbuf) {
 745                         ret = -ENOMEM;
 746                         goto out;
 747                 }
 748         }
 749
 750         while (req.len > 0 || (!usr_data && req.ooblen > 0)) {
 751                 struct mtd_req_stats stats;
 752                 struct mtd_oob_ops ops = {
 753                         .mode = req.mode,
 754                         .len = min_t(size_t, req.len, datbuf_len),
 755                         .ooblen = min_t(size_t, req.ooblen, oobbuf_len),
 756                         .datbuf = datbuf,
 757                         .oobbuf = oobbuf,
 758                         .stats = &stats,
 759                 };
 760
 761                 /*
 762                  * Shorten non-page-aligned, eraseblock-sized reads so that the
 763                  * read ends on an eraseblock boundary.  This is necessary in
 764                  * order to prevent OOB data for some pages from being
 765                  * duplicated in the output of non-page-aligned reads requiring
 766                  * multiple mtd_read_oob() calls to be completed.
 767                  */
 768                 if (ops.len == mtd->erasesize)
 769                         ops.len -= mtd_mod_by_ws(req.start + ops.len, mtd);
 770
 771                 ret = mtd_read_oob(mtd, (loff_t)req.start, &ops);
 772
 773                 req.ecc_stats.uncorrectable_errors +=
 774                         stats.uncorrectable_errors;
 775                 req.ecc_stats.corrected_bitflips += stats.corrected_bitflips;
 776                 req.ecc_stats.max_bitflips =
 777                         max(req.ecc_stats.max_bitflips, stats.max_bitflips);
 778
 779                 if (ret && !mtd_is_bitflip_or_eccerr(ret))
 780                         break;
 781
 782                 if (copy_to_user(usr_data, ops.datbuf, ops.retlen) ||
 783                     copy_to_user(usr_oob, ops.oobbuf, ops.oobretlen)) {
 784                         ret = -EFAULT;
 785                         break;
 786                 }
 787
 788                 req.start += ops.retlen;
 789                 req.len -= ops.retlen;
 790                 usr_data += ops.retlen;
 791
 792                 req.ooblen -= ops.oobretlen;
 793                 usr_oob += ops.oobretlen;
 794         }
 795
 796         /*
 797          * As multiple iterations of the above loop (and therefore multiple
 798          * mtd_read_oob() calls) may be necessary to complete the read request,
 799          * adjust the final return code to ensure it accounts for all detected
 800          * ECC errors.
 801          */
 802         if (!ret || mtd_is_bitflip(ret)) {
 803                 if (req.ecc_stats.uncorrectable_errors > 0)
 804                         ret = -EBADMSG;
 805                 else if (req.ecc_stats.corrected_bitflips > 0)
 806                         ret = -EUCLEAN;
 807         }
 808
 809 out:
 810         req.len = orig_len - req.len;
 811         req.ooblen = orig_ooblen - req.ooblen;
 812
 813         if (copy_to_user(argp, &req, sizeof(req)))
 814                 ret = -EFAULT;
 815
 816         kvfree(datbuf);
 817         kvfree(oobbuf);
 818
 819         return ret;
 820 }
 821
 822 static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg)
 823 {
 824         struct mtd_file_info *mfi = file->private_data;
 825         struct mtd_info *mtd = mfi->mtd;
 826         struct mtd_info *master = mtd_get_master(mtd);
 827         void __user *argp = (void __user *)arg;
 828         int ret = 0;
 829         struct mtd_info_user info;
 830
 831         pr_debug("MTD_ioctl\n");
 832
 833         /*
 834          * Check the file mode to require "dangerous" commands to have write
 835          * permissions.
 836          */
 837         switch (cmd) {
 838         /* "safe" commands */
 839         case MEMGETREGIONCOUNT:
 840         case MEMGETREGIONINFO:
 841         case MEMGETINFO:
 842         case MEMREADOOB:
 843         case MEMREADOOB64:
 844         case MEMREAD:
 845         case MEMISLOCKED:
 846         case MEMGETOOBSEL:
 847         case MEMGETBADBLOCK:
 848         case OTPSELECT:
 849         case OTPGETREGIONCOUNT:
 850         case OTPGETREGIONINFO:
 851         case ECCGETLAYOUT:
 852         case ECCGETSTATS:
 853         case MTDFILEMODE:
 854         case BLKPG:
 855         case BLKRRPART:
 856                 break;
 857
 858         /* "dangerous" commands */
 859         case MEMERASE:
 860         case MEMERASE64:
 861         case MEMLOCK:
 862         case MEMUNLOCK:
 863         case MEMSETBADBLOCK:
 864         case MEMWRITEOOB:
 865         case MEMWRITEOOB64:
 866         case MEMWRITE:
 867         case OTPLOCK:
 868         case OTPERASE:
 869                 if (!(file->f_mode & FMODE_WRITE))
 870                         return -EPERM;
 871                 break;
 872
 873         default:
 874                 return -ENOTTY;
 875         }
 876
 877         switch (cmd) {
 878         case MEMGETREGIONCOUNT:
 879                 if (copy_to_user(argp, &(mtd->numeraseregions), sizeof(int)))
 880                         return -EFAULT;
 881                 break;
 882
 883         case MEMGETREGIONINFO:
 884         {
 885                 uint32_t ur_idx;
 886                 struct mtd_erase_region_info *kr;
 887                 struct region_info_user __user *ur = argp;
 888
 889                 if (get_user(ur_idx, &(ur->regionindex)))
 890                         return -EFAULT;
 891
 892                 if (ur_idx >= mtd->numeraseregions)
 893                         return -EINVAL;
 894
 895                 kr = &(mtd->eraseregions[ur_idx]);
 896
 897                 if (put_user(kr->offset, &(ur->offset))
 898                     || put_user(kr->erasesize, &(ur->erasesize))
 899                     || put_user(kr->numblocks, &(ur->numblocks)))
 900                         return -EFAULT;
 901
 902                 break;
 903         }
 904
 905         case MEMGETINFO:
 906                 memset(&info, 0, sizeof(info));
 907                 info.type       = mtd->type;
 908                 info.flags      = mtd->flags;
 909                 info.size       = mtd->size;
 910                 info.erasesize  = mtd->erasesize;
 911                 info.writesize  = mtd->writesize;
 912                 info.oobsize    = mtd->oobsize;
 913                 /* The below field is obsolete */
 914                 info.padding    = 0;
 915                 if (copy_to_user(argp, &info, sizeof(struct mtd_info_user)))
 916                         return -EFAULT;
 917                 break;
 918
 919         case MEMERASE:
 920         case MEMERASE64:
 921         {
 922                 struct erase_info *erase;
 923
 924                 erase=kzalloc(sizeof(struct erase_info),GFP_KERNEL);
 925                 if (!erase)
 926                         ret = -ENOMEM;
 927                 else {
 928                         if (cmd == MEMERASE64) {
 929                                 struct erase_info_user64 einfo64;
 930
 931                                 if (copy_from_user(&einfo64, argp,
 932                                             sizeof(struct erase_info_user64))) {
 933                                         kfree(erase);
 934                                         return -EFAULT;
 935                                 }
 936                                 erase->addr = einfo64.start;
 937                                 erase->len = einfo64.length;
 938                         } else {
 939                                 struct erase_info_user einfo32;
 940
 941                                 if (copy_from_user(&einfo32, argp,
 942                                             sizeof(struct erase_info_user))) {
 943                                         kfree(erase);
 944                                         return -EFAULT;
 945                                 }
 946                                 erase->addr = einfo32.start;
 947                                 erase->len = einfo32.length;
 948                         }
 949
 950                         ret = mtd_erase(mtd, erase);
 951                         kfree(erase);
 952                 }
 953                 break;
 954         }
 955
 956         case MEMWRITEOOB:
 957         {
 958                 struct mtd_oob_buf buf;
 959                 struct mtd_oob_buf __user *buf_user = argp;
 960
 961                 /* NOTE: writes return length to buf_user->length */
 962                 if (copy_from_user(&buf, argp, sizeof(buf)))
 963                         ret = -EFAULT;
 964                 else
 965                         ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
 966                                 buf.ptr, &buf_user->length);
 967                 break;
 968         }
 969
 970         case MEMREADOOB:
 971         {
 972                 struct mtd_oob_buf buf;
 973                 struct mtd_oob_buf __user *buf_user = argp;
 974
 975                 /* NOTE: writes return length to buf_user->start */
 976                 if (copy_from_user(&buf, argp, sizeof(buf)))
 977                         ret = -EFAULT;
 978                 else
 979                         ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
 980                                 buf.ptr, &buf_user->start);
 981                 break;
 982         }
 983
 984         case MEMWRITEOOB64:
 985         {
 986                 struct mtd_oob_buf64 buf;
 987                 struct mtd_oob_buf64 __user *buf_user = argp;
 988
 989                 if (copy_from_user(&buf, argp, sizeof(buf)))
 990                         ret = -EFAULT;
 991                 else
 992                         ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
 993                                 (void __user *)(uintptr_t)buf.usr_ptr,
 994                                 &buf_user->length);
 995                 break;
 996         }
 997
 998         case MEMREADOOB64:
 999         {
1000                 struct mtd_oob_buf64 buf;
1001                 struct mtd_oob_buf64 __user *buf_user = argp;
1002
1003                 if (copy_from_user(&buf, argp, sizeof(buf)))
1004                         ret = -EFAULT;
1005                 else
1006                         ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
1007                                 (void __user *)(uintptr_t)buf.usr_ptr,
1008                                 &buf_user->length);
1009                 break;
1010         }
1011
1012         case MEMWRITE:
1013         {
1014                 ret = mtdchar_write_ioctl(mtd,
1015                       (struct mtd_write_req __user *)arg);
1016                 break;
1017         }
1018
1019         case MEMREAD:
1020         {
1021                 ret = mtdchar_read_ioctl(mtd,
1022                       (struct mtd_read_req __user *)arg);
1023                 break;
1024         }
1025
1026         case MEMLOCK:
1027         {
1028                 struct erase_info_user einfo;
1029
1030                 if (copy_from_user(&einfo, argp, sizeof(einfo)))
1031                         return -EFAULT;
1032
1033                 ret = mtd_lock(mtd, einfo.start, einfo.length);
1034                 break;
1035         }
1036
1037         case MEMUNLOCK:
1038         {
1039                 struct erase_info_user einfo;
1040
1041                 if (copy_from_user(&einfo, argp, sizeof(einfo)))
1042                         return -EFAULT;
1043
1044                 ret = mtd_unlock(mtd, einfo.start, einfo.length);
1045                 break;
1046         }
1047
1048         case MEMISLOCKED:
1049         {
1050                 struct erase_info_user einfo;
1051
1052                 if (copy_from_user(&einfo, argp, sizeof(einfo)))
1053                         return -EFAULT;
1054
1055                 ret = mtd_is_locked(mtd, einfo.start, einfo.length);
1056                 break;
1057         }
1058
1059         /* Legacy interface */
1060         case MEMGETOOBSEL:
1061         {
1062                 struct nand_oobinfo oi;
1063
1064                 if (!master->ooblayout)
1065                         return -EOPNOTSUPP;
1066
1067                 ret = get_oobinfo(mtd, &oi);
1068                 if (ret)
1069                         return ret;
1070
1071                 if (copy_to_user(argp, &oi, sizeof(struct nand_oobinfo)))
1072                         return -EFAULT;
1073                 break;
1074         }
1075
1076         case MEMGETBADBLOCK:
1077         {
1078                 loff_t offs;
1079
1080                 if (copy_from_user(&offs, argp, sizeof(loff_t)))
1081                         return -EFAULT;
1082                 return mtd_block_isbad(mtd, offs);
1083         }
1084
1085         case MEMSETBADBLOCK:
1086         {
1087                 loff_t offs;
1088
1089                 if (copy_from_user(&offs, argp, sizeof(loff_t)))
1090                         return -EFAULT;
1091                 return mtd_block_markbad(mtd, offs);
1092         }
1093
1094         case OTPSELECT:
1095         {
1096                 int mode;
1097                 if (copy_from_user(&mode, argp, sizeof(int)))
1098                         return -EFAULT;
1099
1100                 mfi->mode = MTD_FILE_MODE_NORMAL;
1101
1102                 ret = otp_select_filemode(mfi, mode);
1103
1104                 file->f_pos = 0;
1105                 break;
1106         }
1107
1108         case OTPGETREGIONCOUNT:
1109         case OTPGETREGIONINFO:
1110         {
1111                 struct otp_info *buf = kmalloc(4096, GFP_KERNEL);
1112                 size_t retlen;
1113                 if (!buf)
1114                         return -ENOMEM;
1115                 switch (mfi->mode) {
1116                 case MTD_FILE_MODE_OTP_FACTORY:
1117                         ret = mtd_get_fact_prot_info(mtd, 4096, &retlen, buf);
1118                         break;
1119                 case MTD_FILE_MODE_OTP_USER:
1120                         ret = mtd_get_user_prot_info(mtd, 4096, &retlen, buf);
1121                         break;
1122                 default:
1123                         ret = -EINVAL;
1124                         break;
1125                 }
1126                 if (!ret) {
1127                         if (cmd == OTPGETREGIONCOUNT) {
1128                                 int nbr = retlen / sizeof(struct otp_info);
1129                                 ret = copy_to_user(argp, &nbr, sizeof(int));
1130                         } else
1131                                 ret = copy_to_user(argp, buf, retlen);
1132                         if (ret)
1133                                 ret = -EFAULT;
1134                 }
1135                 kfree(buf);
1136                 break;
1137         }
1138
1139         case OTPLOCK:
1140         case OTPERASE:
1141         {
1142                 struct otp_info oinfo;
1143
1144                 if (mfi->mode != MTD_FILE_MODE_OTP_USER)
1145                         return -EINVAL;
1146                 if (copy_from_user(&oinfo, argp, sizeof(oinfo)))
1147                         return -EFAULT;
1148                 if (cmd == OTPLOCK)
1149                         ret = mtd_lock_user_prot_reg(mtd, oinfo.start, oinfo.length);
1150                 else
1151                         ret = mtd_erase_user_prot_reg(mtd, oinfo.start, oinfo.length);
1152                 break;
1153         }
1154
1155         /* This ioctl is being deprecated - it truncates the ECC layout */
1156         case ECCGETLAYOUT:
1157         {
1158                 struct nand_ecclayout_user *usrlay;
1159
1160                 if (!master->ooblayout)
1161                         return -EOPNOTSUPP;
1162
1163                 usrlay = kmalloc(sizeof(*usrlay), GFP_KERNEL);
1164                 if (!usrlay)
1165                         return -ENOMEM;
1166
1167                 shrink_ecclayout(mtd, usrlay);
1168
1169                 if (copy_to_user(argp, usrlay, sizeof(*usrlay)))
1170                         ret = -EFAULT;
1171                 kfree(usrlay);
1172                 break;
1173         }
1174
1175         case ECCGETSTATS:
1176         {
1177                 if (copy_to_user(argp, &mtd->ecc_stats,
1178                                  sizeof(struct mtd_ecc_stats)))
1179                         return -EFAULT;
1180                 break;
1181         }
1182
1183         case MTDFILEMODE:
1184         {
1185                 mfi->mode = 0;
1186
1187                 switch(arg) {
1188                 case MTD_FILE_MODE_OTP_FACTORY:
1189                 case MTD_FILE_MODE_OTP_USER:
1190                         ret = otp_select_filemode(mfi, arg);
1191                         break;
1192
1193                 case MTD_FILE_MODE_RAW:
1194                         if (!mtd_has_oob(mtd))
1195                                 return -EOPNOTSUPP;
1196                         mfi->mode = arg;
1197                         break;
1198
1199                 case MTD_FILE_MODE_NORMAL:
1200                         break;
1201                 default:
1202                         ret = -EINVAL;
1203                 }
1204                 file->f_pos = 0;
1205                 break;
1206         }
1207
1208         case BLKPG:
1209         {
1210                 struct blkpg_ioctl_arg __user *blk_arg = argp;
1211                 struct blkpg_ioctl_arg a;
1212
1213                 if (copy_from_user(&a, blk_arg, sizeof(a)))
1214                         ret = -EFAULT;
1215                 else
1216                         ret = mtdchar_blkpg_ioctl(mtd, &a);
1217                 break;
1218         }
1219
1220         case BLKRRPART:
1221         {
1222                 /* No reread partition feature. Just return ok */
1223                 ret = 0;
1224                 break;
1225         }
1226         }
1227
1228         return ret;
1229 } /* memory_ioctl */
1230
1231 static long mtdchar_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
1232 {
1233         struct mtd_file_info *mfi = file->private_data;
1234         struct mtd_info *mtd = mfi->mtd;
1235         struct mtd_info *master = mtd_get_master(mtd);
1236         int ret;
1237
1238         mutex_lock(&master->master.chrdev_lock);
1239         ret = mtdchar_ioctl(file, cmd, arg);
1240         mutex_unlock(&master->master.chrdev_lock);
1241
1242         return ret;
1243 }
1244
1245 #ifdef CONFIG_COMPAT
1246
1247 struct mtd_oob_buf32 {
1248         u_int32_t start;
1249         u_int32_t length;
1250         compat_caddr_t ptr;     /* unsigned char* */
1251 };
1252
1253 #define MEMWRITEOOB32           _IOWR('M', 3, struct mtd_oob_buf32)
1254 #define MEMREADOOB32            _IOWR('M', 4, struct mtd_oob_buf32)
1255
1256 static long mtdchar_compat_ioctl(struct file *file, unsigned int cmd,
1257         unsigned long arg)
1258 {
1259         struct mtd_file_info *mfi = file->private_data;
1260         struct mtd_info *mtd = mfi->mtd;
1261         struct mtd_info *master = mtd_get_master(mtd);
1262         void __user *argp = compat_ptr(arg);
1263         int ret = 0;
1264
1265         mutex_lock(&master->master.chrdev_lock);
1266
1267         switch (cmd) {
1268         case MEMWRITEOOB32:
1269         {
1270                 struct mtd_oob_buf32 buf;
1271                 struct mtd_oob_buf32 __user *buf_user = argp;
1272
1273                 if (!(file->f_mode & FMODE_WRITE)) {
1274                         ret = -EPERM;
1275                         break;
1276                 }
1277
1278                 if (copy_from_user(&buf, argp, sizeof(buf)))
1279                         ret = -EFAULT;
1280                 else
1281                         ret = mtdchar_writeoob(file, mtd, buf.start,
1282                                 buf.length, compat_ptr(buf.ptr),
1283                                 &buf_user->length);
1284                 break;
1285         }
1286
1287         case MEMREADOOB32:
1288         {
1289                 struct mtd_oob_buf32 buf;
1290                 struct mtd_oob_buf32 __user *buf_user = argp;
1291
1292                 /* NOTE: writes return length to buf->start */
1293                 if (copy_from_user(&buf, argp, sizeof(buf)))
1294                         ret = -EFAULT;
1295                 else
1296                         ret = mtdchar_readoob(file, mtd, buf.start,
1297                                 buf.length, compat_ptr(buf.ptr),
1298                                 &buf_user->start);
1299                 break;
1300         }
1301
1302         case BLKPG:
1303         {
1304                 /* Convert from blkpg_compat_ioctl_arg to blkpg_ioctl_arg */
1305                 struct blkpg_compat_ioctl_arg __user *uarg = argp;
1306                 struct blkpg_compat_ioctl_arg compat_arg;
1307                 struct blkpg_ioctl_arg a;
1308
1309                 if (copy_from_user(&compat_arg, uarg, sizeof(compat_arg))) {
1310                         ret = -EFAULT;
1311                         break;
1312                 }
1313
1314                 memset(&a, 0, sizeof(a));
1315                 a.op = compat_arg.op;
1316                 a.flags = compat_arg.flags;
1317                 a.datalen = compat_arg.datalen;
1318                 a.data = compat_ptr(compat_arg.data);
1319
1320                 ret = mtdchar_blkpg_ioctl(mtd, &a);
1321                 break;
1322         }
1323
1324         default:
1325                 ret = mtdchar_ioctl(file, cmd, (unsigned long)argp);
1326         }
1327
1328         mutex_unlock(&master->master.chrdev_lock);
1329
1330         return ret;
1331 }
1332
1333 #endif /* CONFIG_COMPAT */
1334
1335 /*
1336  * try to determine where a shared mapping can be made
1337  * - only supported for NOMMU at the moment (MMU can't doesn't copy private
1338  *   mappings)
1339  */
1340 #ifndef CONFIG_MMU
1341 static unsigned long mtdchar_get_unmapped_area(struct file *file,
1342                                            unsigned long addr,
1343                                            unsigned long len,
1344                                            unsigned long pgoff,
1345                                            unsigned long flags)
1346 {
1347         struct mtd_file_info *mfi = file->private_data;
1348         struct mtd_info *mtd = mfi->mtd;
1349         unsigned long offset;
1350         int ret;
1351
1352         if (addr != 0)
1353                 return (unsigned long) -EINVAL;
1354
1355         if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT))
1356                 return (unsigned long) -EINVAL;
1357
1358         offset = pgoff << PAGE_SHIFT;
1359         if (offset > mtd->size - len)
1360                 return (unsigned long) -EINVAL;
1361
1362         ret = mtd_get_unmapped_area(mtd, len, offset, flags);
1363         return ret == -EOPNOTSUPP ? -ENODEV : ret;
1364 }
1365
1366 static unsigned mtdchar_mmap_capabilities(struct file *file)
1367 {
1368         struct mtd_file_info *mfi = file->private_data;
1369
1370         return mtd_mmap_capabilities(mfi->mtd);
1371 }
1372 #endif
1373
1374 /*
1375  * set up a mapping for shared memory segments
1376  */
1377 static int mtdchar_mmap(struct file *file, struct vm_area_struct *vma)
1378 {
1379 #ifdef CONFIG_MMU
1380         struct mtd_file_info *mfi = file->private_data;
1381         struct mtd_info *mtd = mfi->mtd;
1382         struct map_info *map = mtd->priv;
1383
1384         /* This is broken because it assumes the MTD device is map-based
1385            and that mtd->priv is a valid struct map_info.  It should be
1386            replaced with something that uses the mtd_get_unmapped_area()
1387            operation properly. */
1388         if (0 /*mtd->type == MTD_RAM || mtd->type == MTD_ROM*/) {
1389 #ifdef pgprot_noncached
1390                 if (file->f_flags & O_DSYNC || map->phys >= __pa(high_memory))
1391                         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1392 #endif
1393                 return vm_iomap_memory(vma, map->phys, map->size);
1394         }
1395         return -ENODEV;
1396 #else
1397         return vma->vm_flags & VM_SHARED ? 0 : -EACCES;
1398 #endif
1399 }
1400
1401 static const struct file_operations mtd_fops = {
1402         .owner          = THIS_MODULE,
1403         .llseek         = mtdchar_lseek,
1404         .read           = mtdchar_read,
1405         .write          = mtdchar_write,
1406         .unlocked_ioctl = mtdchar_unlocked_ioctl,
1407 #ifdef CONFIG_COMPAT
1408         .compat_ioctl   = mtdchar_compat_ioctl,
1409 #endif
1410         .open           = mtdchar_open,
1411         .release        = mtdchar_close,
1412         .mmap           = mtdchar_mmap,
1413 #ifndef CONFIG_MMU
1414         .get_unmapped_area = mtdchar_get_unmapped_area,
1415         .mmap_capabilities = mtdchar_mmap_capabilities,
1416 #endif
1417 };
1418
1419 int __init init_mtdchar(void)
1420 {
1421         int ret;
1422
1423         ret = __register_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS,
1424                                    "mtd", &mtd_fops);
1425         if (ret < 0) {
1426                 pr_err("Can't allocate major number %d for MTD\n",
1427                        MTD_CHAR_MAJOR);
1428                 return ret;
1429         }
1430
1431         return ret;
1432 }
1433
1434 void __exit cleanup_mtdchar(void)
1435 {
1436         __unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1437 }
1438
1439 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);