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