drivers/mtd/mtdchar.c

   1 /*
   2  * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  *
  18  */
  19
  20 #include <linux/device.h>
  21 #include <linux/fs.h>
  22 #include <linux/mm.h>
  23 #include <linux/err.h>
  24 #include <linux/init.h>
  25 #include <linux/kernel.h>
  26 #include <linux/module.h>
  27 #include <linux/slab.h>
  28 #include <linux/sched.h>
  29 #include <linux/mutex.h>
  30 #include <linux/backing-dev.h>
  31 #include <linux/compat.h>
  32 #include <linux/mount.h>
  33 #include <linux/blkpg.h>
  34 #include <linux/magic.h>
  35 #include <linux/major.h>
  36 #include <linux/mtd/mtd.h>
  37 #include <linux/mtd/partitions.h>
  38 #include <linux/mtd/map.h>
  39
  40 #include <asm/uaccess.h>
  41
  42 #include "mtdcore.h"
  43
  44 static DEFINE_MUTEX(mtd_mutex);
  45
  46 /*
  47  * Data structure to hold the pointer to the mtd device as well
  48  * as mode information of various use cases.
  49  */
  50 struct mtd_file_info {
  51         struct mtd_info *mtd;
  52         enum mtd_file_modes mode;
  53 };
  54
  55 static loff_t mtdchar_lseek(struct file *file, loff_t offset, int orig)
  56 {
  57         struct mtd_file_info *mfi = file->private_data;
  58         return fixed_size_llseek(file, offset, orig, mfi->mtd->size);
  59 }
  60
  61 static int mtdchar_open(struct inode *inode, struct file *file)
  62 {
  63         int minor = iminor(inode);
  64         int devnum = minor >> 1;
  65         int ret = 0;
  66         struct mtd_info *mtd;
  67         struct mtd_file_info *mfi;
  68
  69         pr_debug("MTD_open\n");
  70
  71         /* You can't open the RO devices RW */
  72         if ((file->f_mode & FMODE_WRITE) && (minor & 1))
  73                 return -EACCES;
  74
  75         mutex_lock(&mtd_mutex);
  76         mtd = get_mtd_device(NULL, devnum);
  77
  78         if (IS_ERR(mtd)) {
  79                 ret = PTR_ERR(mtd);
  80                 goto out;
  81         }
  82
  83         if (mtd->type == MTD_ABSENT) {
  84                 ret = -ENODEV;
  85                 goto out1;
  86         }
  87
  88         /* You can't open it RW if it's not a writeable device */
  89         if ((file->f_mode & FMODE_WRITE) && !(mtd->flags & MTD_WRITEABLE)) {
  90                 ret = -EACCES;
  91                 goto out1;
  92         }
  93
  94         mfi = kzalloc(sizeof(*mfi), GFP_KERNEL);
  95         if (!mfi) {
  96                 ret = -ENOMEM;
  97                 goto out1;
  98         }
  99         mfi->mtd = mtd;
 100         file->private_data = mfi;
 101         mutex_unlock(&mtd_mutex);
 102         return 0;
 103
 104 out1:
 105         put_mtd_device(mtd);
 106 out:
 107         mutex_unlock(&mtd_mutex);
 108         return ret;
 109 } /* mtdchar_open */
 110
 111 /*====================================================================*/
 112
 113 static int mtdchar_close(struct inode *inode, struct file *file)
 114 {
 115         struct mtd_file_info *mfi = file->private_data;
 116         struct mtd_info *mtd = mfi->mtd;
 117
 118         pr_debug("MTD_close\n");
 119
 120         /* Only sync if opened RW */
 121         if ((file->f_mode & FMODE_WRITE))
 122                 mtd_sync(mtd);
 123
 124         put_mtd_device(mtd);
 125         file->private_data = NULL;
 126         kfree(mfi);
 127
 128         return 0;
 129 } /* mtdchar_close */
 130
 131 /* Back in June 2001, dwmw2 wrote:
 132  *
 133  *   FIXME: This _really_ needs to die. In 2.5, we should lock the
 134  *   userspace buffer down and use it directly with readv/writev.
 135  *
 136  * The implementation below, using mtd_kmalloc_up_to, mitigates
 137  * allocation failures when the system is under low-memory situations
 138  * or if memory is highly fragmented at the cost of reducing the
 139  * performance of the requested transfer due to a smaller buffer size.
 140  *
 141  * A more complex but more memory-efficient implementation based on
 142  * get_user_pages and iovecs to cover extents of those pages is a
 143  * longer-term goal, as intimated by dwmw2 above. However, for the
 144  * write case, this requires yet more complex head and tail transfer
 145  * handling when those head and tail offsets and sizes are such that
 146  * alignment requirements are not met in the NAND subdriver.
 147  */
 148
 149 static ssize_t mtdchar_read(struct file *file, char __user *buf, size_t count,
 150                         loff_t *ppos)
 151 {
 152         struct mtd_file_info *mfi = file->private_data;
 153         struct mtd_info *mtd = mfi->mtd;
 154         size_t retlen;
 155         size_t total_retlen=0;
 156         int ret=0;
 157         int len;
 158         size_t size = count;
 159         char *kbuf;
 160
 161         pr_debug("MTD_read\n");
 162
 163         if (*ppos + count > mtd->size)
 164                 count = mtd->size - *ppos;
 165
 166         if (!count)
 167                 return 0;
 168
 169         kbuf = mtd_kmalloc_up_to(mtd, &size);
 170         if (!kbuf)
 171                 return -ENOMEM;
 172
 173         while (count) {
 174                 len = min_t(size_t, count, size);
 175
 176                 switch (mfi->mode) {
 177                 case MTD_FILE_MODE_OTP_FACTORY:
 178                         ret = mtd_read_fact_prot_reg(mtd, *ppos, len,
 179                                                      &retlen, kbuf);
 180                         break;
 181                 case MTD_FILE_MODE_OTP_USER:
 182                         ret = mtd_read_user_prot_reg(mtd, *ppos, len,
 183                                                      &retlen, kbuf);
 184                         break;
 185                 case MTD_FILE_MODE_RAW:
 186                 {
 187                         struct mtd_oob_ops ops;
 188
 189                         ops.mode = MTD_OPS_RAW;
 190                         ops.datbuf = kbuf;
 191                         ops.oobbuf = NULL;
 192                         ops.len = len;
 193
 194                         ret = mtd_read_oob(mtd, *ppos, &ops);
 195                         retlen = ops.retlen;
 196                         break;
 197                 }
 198                 default:
 199                         ret = mtd_read(mtd, *ppos, len, &retlen, kbuf);
 200                 }
 201                 /* Nand returns -EBADMSG on ECC errors, but it returns
 202                  * the data. For our userspace tools it is important
 203                  * to dump areas with ECC errors!
 204                  * For kernel internal usage it also might return -EUCLEAN
 205                  * to signal the caller that a bitflip has occurred and has
 206                  * been corrected by the ECC algorithm.
 207                  * Userspace software which accesses NAND this way
 208                  * must be aware of the fact that it deals with NAND
 209                  */
 210                 if (!ret || mtd_is_bitflip_or_eccerr(ret)) {
 211                         *ppos += retlen;
 212                         if (copy_to_user(buf, kbuf, retlen)) {
 213                                 kfree(kbuf);
 214                                 return -EFAULT;
 215                         }
 216                         else
 217                                 total_retlen += retlen;
 218
 219                         count -= retlen;
 220                         buf += retlen;
 221                         if (retlen == 0)
 222                                 count = 0;
 223                 }
 224                 else {
 225                         kfree(kbuf);
 226                         return ret;
 227                 }
 228
 229         }
 230
 231         kfree(kbuf);
 232         return total_retlen;
 233 } /* mtdchar_read */
 234
 235 static ssize_t mtdchar_write(struct file *file, const char __user *buf, size_t count,
 236                         loff_t *ppos)
 237 {
 238         struct mtd_file_info *mfi = file->private_data;
 239         struct mtd_info *mtd = mfi->mtd;
 240         size_t size = count;
 241         char *kbuf;
 242         size_t retlen;
 243         size_t total_retlen=0;
 244         int ret=0;
 245         int len;
 246
 247         pr_debug("MTD_write\n");
 248
 249         if (*ppos == mtd->size)
 250                 return -ENOSPC;
 251
 252         if (*ppos + count > mtd->size)
 253                 count = mtd->size - *ppos;
 254
 255         if (!count)
 256                 return 0;
 257
 258         kbuf = mtd_kmalloc_up_to(mtd, &size);
 259         if (!kbuf)
 260                 return -ENOMEM;
 261
 262         while (count) {
 263                 len = min_t(size_t, count, size);
 264
 265                 if (copy_from_user(kbuf, buf, len)) {
 266                         kfree(kbuf);
 267                         return -EFAULT;
 268                 }
 269
 270                 switch (mfi->mode) {
 271                 case MTD_FILE_MODE_OTP_FACTORY:
 272                         ret = -EROFS;
 273                         break;
 274                 case MTD_FILE_MODE_OTP_USER:
 275                         ret = mtd_write_user_prot_reg(mtd, *ppos, len,
 276                                                       &retlen, kbuf);
 277                         break;
 278
 279                 case MTD_FILE_MODE_RAW:
 280                 {
 281                         struct mtd_oob_ops ops;
 282
 283                         ops.mode = MTD_OPS_RAW;
 284                         ops.datbuf = kbuf;
 285                         ops.oobbuf = NULL;
 286                         ops.ooboffs = 0;
 287                         ops.len = len;
 288
 289                         ret = mtd_write_oob(mtd, *ppos, &ops);
 290                         retlen = ops.retlen;
 291                         break;
 292                 }
 293
 294                 default:
 295                         ret = mtd_write(mtd, *ppos, len, &retlen, kbuf);
 296                 }
 297
 298                 /*
 299                  * Return -ENOSPC only if no data could be written at all.
 300                  * Otherwise just return the number of bytes that actually
 301                  * have been written.
 302                  */
 303                 if ((ret == -ENOSPC) && (total_retlen))
 304                         break;
 305
 306                 if (!ret) {
 307                         *ppos += retlen;
 308                         total_retlen += retlen;
 309                         count -= retlen;
 310                         buf += retlen;
 311                 }
 312                 else {
 313                         kfree(kbuf);
 314                         return ret;
 315                 }
 316         }
 317
 318         kfree(kbuf);
 319         return total_retlen;
 320 } /* mtdchar_write */
 321
 322 /*======================================================================
 323
 324     IOCTL calls for getting device parameters.
 325
 326 ======================================================================*/
 327 static void mtdchar_erase_callback (struct erase_info *instr)
 328 {
 329         wake_up((wait_queue_head_t *)instr->priv);
 330 }
 331
 332 static int otp_select_filemode(struct mtd_file_info *mfi, int mode)
 333 {
 334         struct mtd_info *mtd = mfi->mtd;
 335         size_t retlen;
 336
 337         switch (mode) {
 338         case MTD_OTP_FACTORY:
 339                 if (mtd_read_fact_prot_reg(mtd, -1, 0, &retlen, NULL) ==
 340                                 -EOPNOTSUPP)
 341                         return -EOPNOTSUPP;
 342
 343                 mfi->mode = MTD_FILE_MODE_OTP_FACTORY;
 344                 break;
 345         case MTD_OTP_USER:
 346                 if (mtd_read_user_prot_reg(mtd, -1, 0, &retlen, NULL) ==
 347                                 -EOPNOTSUPP)
 348                         return -EOPNOTSUPP;
 349
 350                 mfi->mode = MTD_FILE_MODE_OTP_USER;
 351                 break;
 352         case MTD_OTP_OFF:
 353                 mfi->mode = MTD_FILE_MODE_NORMAL;
 354                 break;
 355         default:
 356                 return -EINVAL;
 357         }
 358
 359         return 0;
 360 }
 361
 362 static int mtdchar_writeoob(struct file *file, struct mtd_info *mtd,
 363         uint64_t start, uint32_t length, void __user *ptr,
 364         uint32_t __user *retp)
 365 {
 366         struct mtd_file_info *mfi = file->private_data;
 367         struct mtd_oob_ops ops;
 368         uint32_t retlen;
 369         int ret = 0;
 370
 371         if (!(file->f_mode & FMODE_WRITE))
 372                 return -EPERM;
 373
 374         if (length > 4096)
 375                 return -EINVAL;
 376
 377         if (!mtd->_write_oob)
 378                 ret = -EOPNOTSUPP;
 379         else
 380                 ret = access_ok(VERIFY_READ, ptr, length) ? 0 : -EFAULT;
 381
 382         if (ret)
 383                 return ret;
 384
 385         ops.ooblen = length;
 386         ops.ooboffs = start & (mtd->writesize - 1);
 387         ops.datbuf = NULL;
 388         ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
 389                 MTD_OPS_PLACE_OOB;
 390
 391         if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
 392                 return -EINVAL;
 393
 394         ops.oobbuf = memdup_user(ptr, length);
 395         if (IS_ERR(ops.oobbuf))
 396                 return PTR_ERR(ops.oobbuf);
 397
 398         start &= ~((uint64_t)mtd->writesize - 1);
 399         ret = mtd_write_oob(mtd, start, &ops);
 400
 401         if (ops.oobretlen > 0xFFFFFFFFU)
 402                 ret = -EOVERFLOW;
 403         retlen = ops.oobretlen;
 404         if (copy_to_user(retp, &retlen, sizeof(length)))
 405                 ret = -EFAULT;
 406
 407         kfree(ops.oobbuf);
 408         return ret;
 409 }
 410
 411 static int mtdchar_readoob(struct file *file, struct mtd_info *mtd,
 412         uint64_t start, uint32_t length, void __user *ptr,
 413         uint32_t __user *retp)
 414 {
 415         struct mtd_file_info *mfi = file->private_data;
 416         struct mtd_oob_ops ops;
 417         int ret = 0;
 418
 419         if (length > 4096)
 420                 return -EINVAL;
 421
 422         if (!access_ok(VERIFY_WRITE, ptr, length))
 423                 return -EFAULT;
 424
 425         ops.ooblen = length;
 426         ops.ooboffs = start & (mtd->writesize - 1);
 427         ops.datbuf = NULL;
 428         ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
 429                 MTD_OPS_PLACE_OOB;
 430
 431         if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
 432                 return -EINVAL;
 433
 434         ops.oobbuf = kmalloc(length, GFP_KERNEL);
 435         if (!ops.oobbuf)
 436                 return -ENOMEM;
 437
 438         start &= ~((uint64_t)mtd->writesize - 1);
 439         ret = mtd_read_oob(mtd, start, &ops);
 440
 441         if (put_user(ops.oobretlen, retp))
 442                 ret = -EFAULT;
 443         else if (ops.oobretlen && copy_to_user(ptr, ops.oobbuf,
 444                                             ops.oobretlen))
 445                 ret = -EFAULT;
 446
 447         kfree(ops.oobbuf);
 448
 449         /*
 450          * NAND returns -EBADMSG on ECC errors, but it returns the OOB
 451          * data. For our userspace tools it is important to dump areas
 452          * with ECC errors!
 453          * For kernel internal usage it also might return -EUCLEAN
 454          * to signal the caller that a bitflip has occured and has
 455          * been corrected by the ECC algorithm.
 456          *
 457          * Note: currently the standard NAND function, nand_read_oob_std,
 458          * does not calculate ECC for the OOB area, so do not rely on
 459          * this behavior unless you have replaced it with your own.
 460          */
 461         if (mtd_is_bitflip_or_eccerr(ret))
 462                 return 0;
 463
 464         return ret;
 465 }
 466
 467 /*
 468  * Copies (and truncates, if necessary) data from the larger struct,
 469  * nand_ecclayout, to the smaller, deprecated layout struct,
 470  * nand_ecclayout_user. This is necessary only to support the deprecated
 471  * API ioctl ECCGETLAYOUT while allowing all new functionality to use
 472  * nand_ecclayout flexibly (i.e. the struct may change size in new
 473  * releases without requiring major rewrites).
 474  */
 475 static int shrink_ecclayout(const struct nand_ecclayout *from,
 476                 struct nand_ecclayout_user *to)
 477 {
 478         int i;
 479
 480         if (!from || !to)
 481                 return -EINVAL;
 482
 483         memset(to, 0, sizeof(*to));
 484
 485         to->eccbytes = min((int)from->eccbytes, MTD_MAX_ECCPOS_ENTRIES);
 486         for (i = 0; i < to->eccbytes; i++)
 487                 to->eccpos[i] = from->eccpos[i];
 488
 489         for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES; i++) {
 490                 if (from->oobfree[i].length == 0 &&
 491                                 from->oobfree[i].offset == 0)
 492                         break;
 493                 to->oobavail += from->oobfree[i].length;
 494                 to->oobfree[i] = from->oobfree[i];
 495         }
 496
 497         return 0;
 498 }
 499
 500 static int mtdchar_blkpg_ioctl(struct mtd_info *mtd,
 501                                struct blkpg_ioctl_arg *arg)
 502 {
 503         struct blkpg_partition p;
 504
 505         if (!capable(CAP_SYS_ADMIN))
 506                 return -EPERM;
 507
 508         if (copy_from_user(&p, arg->data, sizeof(p)))
 509                 return -EFAULT;
 510
 511         switch (arg->op) {
 512         case BLKPG_ADD_PARTITION:
 513
 514                 /* Only master mtd device must be used to add partitions */
 515                 if (mtd_is_partition(mtd))
 516                         return -EINVAL;
 517
 518                 /* Sanitize user input */
 519                 p.devname[BLKPG_DEVNAMELTH - 1] = '\0';
 520
 521                 return mtd_add_partition(mtd, p.devname, p.start, p.length);
 522
 523         case BLKPG_DEL_PARTITION:
 524
 525                 if (p.pno < 0)
 526                         return -EINVAL;
 527
 528                 return mtd_del_partition(mtd, p.pno);
 529
 530         default:
 531                 return -EINVAL;
 532         }
 533 }
 534
 535 static int mtdchar_write_ioctl(struct mtd_info *mtd,
 536                 struct mtd_write_req __user *argp)
 537 {
 538         struct mtd_write_req req;
 539         struct mtd_oob_ops ops;
 540         const void __user *usr_data, *usr_oob;
 541         int ret;
 542
 543         if (copy_from_user(&req, argp, sizeof(req)))
 544                 return -EFAULT;
 545
 546         usr_data = (const void __user *)(uintptr_t)req.usr_data;
 547         usr_oob = (const void __user *)(uintptr_t)req.usr_oob;
 548         if (!access_ok(VERIFY_READ, usr_data, req.len) ||
 549             !access_ok(VERIFY_READ, usr_oob, req.ooblen))
 550                 return -EFAULT;
 551
 552         if (!mtd->_write_oob)
 553                 return -EOPNOTSUPP;
 554
 555         ops.mode = req.mode;
 556         ops.len = (size_t)req.len;
 557         ops.ooblen = (size_t)req.ooblen;
 558         ops.ooboffs = 0;
 559
 560         if (usr_data) {
 561                 ops.datbuf = memdup_user(usr_data, ops.len);
 562                 if (IS_ERR(ops.datbuf))
 563                         return PTR_ERR(ops.datbuf);
 564         } else {
 565                 ops.datbuf = NULL;
 566         }
 567
 568         if (usr_oob) {
 569                 ops.oobbuf = memdup_user(usr_oob, ops.ooblen);
 570                 if (IS_ERR(ops.oobbuf)) {
 571                         kfree(ops.datbuf);
 572                         return PTR_ERR(ops.oobbuf);
 573                 }
 574         } else {
 575                 ops.oobbuf = NULL;
 576         }
 577
 578         ret = mtd_write_oob(mtd, (loff_t)req.start, &ops);
 579
 580         kfree(ops.datbuf);
 581         kfree(ops.oobbuf);
 582
 583         return ret;
 584 }
 585
 586 static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg)
 587 {
 588         struct mtd_file_info *mfi = file->private_data;
 589         struct mtd_info *mtd = mfi->mtd;
 590         void __user *argp = (void __user *)arg;
 591         int ret = 0;
 592         u_long size;
 593         struct mtd_info_user info;
 594
 595         pr_debug("MTD_ioctl\n");
 596
 597         size = (cmd & IOCSIZE_MASK) >> IOCSIZE_SHIFT;
 598         if (cmd & IOC_IN) {
 599                 if (!access_ok(VERIFY_READ, argp, size))
 600                         return -EFAULT;
 601         }
 602         if (cmd & IOC_OUT) {
 603                 if (!access_ok(VERIFY_WRITE, argp, size))
 604                         return -EFAULT;
 605         }
 606
 607         switch (cmd) {
 608         case MEMGETREGIONCOUNT:
 609                 if (copy_to_user(argp, &(mtd->numeraseregions), sizeof(int)))
 610                         return -EFAULT;
 611                 break;
 612
 613         case MEMGETREGIONINFO:
 614         {
 615                 uint32_t ur_idx;
 616                 struct mtd_erase_region_info *kr;
 617                 struct region_info_user __user *ur = argp;
 618
 619                 if (get_user(ur_idx, &(ur->regionindex)))
 620                         return -EFAULT;
 621
 622                 if (ur_idx >= mtd->numeraseregions)
 623                         return -EINVAL;
 624
 625                 kr = &(mtd->eraseregions[ur_idx]);
 626
 627                 if (put_user(kr->offset, &(ur->offset))
 628                     || put_user(kr->erasesize, &(ur->erasesize))
 629                     || put_user(kr->numblocks, &(ur->numblocks)))
 630                         return -EFAULT;
 631
 632                 break;
 633         }
 634
 635         case MEMGETINFO:
 636                 memset(&info, 0, sizeof(info));
 637                 info.type       = mtd->type;
 638                 info.flags      = mtd->flags;
 639                 info.size       = mtd->size;
 640                 info.erasesize  = mtd->erasesize;
 641                 info.writesize  = mtd->writesize;
 642                 info.oobsize    = mtd->oobsize;
 643                 /* The below field is obsolete */
 644                 info.padding    = 0;
 645                 if (copy_to_user(argp, &info, sizeof(struct mtd_info_user)))
 646                         return -EFAULT;
 647                 break;
 648
 649         case MEMERASE:
 650         case MEMERASE64:
 651         {
 652                 struct erase_info *erase;
 653
 654                 if(!(file->f_mode & FMODE_WRITE))
 655                         return -EPERM;
 656
 657                 erase=kzalloc(sizeof(struct erase_info),GFP_KERNEL);
 658                 if (!erase)
 659                         ret = -ENOMEM;
 660                 else {
 661                         wait_queue_head_t waitq;
 662                         DECLARE_WAITQUEUE(wait, current);
 663
 664                         init_waitqueue_head(&waitq);
 665
 666                         if (cmd == MEMERASE64) {
 667                                 struct erase_info_user64 einfo64;
 668
 669                                 if (copy_from_user(&einfo64, argp,
 670                                             sizeof(struct erase_info_user64))) {
 671                                         kfree(erase);
 672                                         return -EFAULT;
 673                                 }
 674                                 erase->addr = einfo64.start;
 675                                 erase->len = einfo64.length;
 676                         } else {
 677                                 struct erase_info_user einfo32;
 678
 679                                 if (copy_from_user(&einfo32, argp,
 680                                             sizeof(struct erase_info_user))) {
 681                                         kfree(erase);
 682                                         return -EFAULT;
 683                                 }
 684                                 erase->addr = einfo32.start;
 685                                 erase->len = einfo32.length;
 686                         }
 687                         erase->mtd = mtd;
 688                         erase->callback = mtdchar_erase_callback;
 689                         erase->priv = (unsigned long)&waitq;
 690
 691                         /*
 692                           FIXME: Allow INTERRUPTIBLE. Which means
 693                           not having the wait_queue head on the stack.
 694
 695                           If the wq_head is on the stack, and we
 696                           leave because we got interrupted, then the
 697                           wq_head is no longer there when the
 698                           callback routine tries to wake us up.
 699                         */
 700                         ret = mtd_erase(mtd, erase);
 701                         if (!ret) {
 702                                 set_current_state(TASK_UNINTERRUPTIBLE);
 703                                 add_wait_queue(&waitq, &wait);
 704                                 if (erase->state != MTD_ERASE_DONE &&
 705                                     erase->state != MTD_ERASE_FAILED)
 706                                         schedule();
 707                                 remove_wait_queue(&waitq, &wait);
 708                                 set_current_state(TASK_RUNNING);
 709
 710                                 ret = (erase->state == MTD_ERASE_FAILED)?-EIO:0;
 711                         }
 712                         kfree(erase);
 713                 }
 714                 break;
 715         }
 716
 717         case MEMWRITEOOB:
 718         {
 719                 struct mtd_oob_buf buf;
 720                 struct mtd_oob_buf __user *buf_user = argp;
 721
 722                 /* NOTE: writes return length to buf_user->length */
 723                 if (copy_from_user(&buf, argp, sizeof(buf)))
 724                         ret = -EFAULT;
 725                 else
 726                         ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
 727                                 buf.ptr, &buf_user->length);
 728                 break;
 729         }
 730
 731         case MEMREADOOB:
 732         {
 733                 struct mtd_oob_buf buf;
 734                 struct mtd_oob_buf __user *buf_user = argp;
 735
 736                 /* NOTE: writes return length to buf_user->start */
 737                 if (copy_from_user(&buf, argp, sizeof(buf)))
 738                         ret = -EFAULT;
 739                 else
 740                         ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
 741                                 buf.ptr, &buf_user->start);
 742                 break;
 743         }
 744
 745         case MEMWRITEOOB64:
 746         {
 747                 struct mtd_oob_buf64 buf;
 748                 struct mtd_oob_buf64 __user *buf_user = argp;
 749
 750                 if (copy_from_user(&buf, argp, sizeof(buf)))
 751                         ret = -EFAULT;
 752                 else
 753                         ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
 754                                 (void __user *)(uintptr_t)buf.usr_ptr,
 755                                 &buf_user->length);
 756                 break;
 757         }
 758
 759         case MEMREADOOB64:
 760         {
 761                 struct mtd_oob_buf64 buf;
 762                 struct mtd_oob_buf64 __user *buf_user = argp;
 763
 764                 if (copy_from_user(&buf, argp, sizeof(buf)))
 765                         ret = -EFAULT;
 766                 else
 767                         ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
 768                                 (void __user *)(uintptr_t)buf.usr_ptr,
 769                                 &buf_user->length);
 770                 break;
 771         }
 772
 773         case MEMWRITE:
 774         {
 775                 ret = mtdchar_write_ioctl(mtd,
 776                       (struct mtd_write_req __user *)arg);
 777                 break;
 778         }
 779
 780         case MEMLOCK:
 781         {
 782                 struct erase_info_user einfo;
 783
 784                 if (copy_from_user(&einfo, argp, sizeof(einfo)))
 785                         return -EFAULT;
 786
 787                 ret = mtd_lock(mtd, einfo.start, einfo.length);
 788                 break;
 789         }
 790
 791         case MEMUNLOCK:
 792         {
 793                 struct erase_info_user einfo;
 794
 795                 if (copy_from_user(&einfo, argp, sizeof(einfo)))
 796                         return -EFAULT;
 797
 798                 ret = mtd_unlock(mtd, einfo.start, einfo.length);
 799                 break;
 800         }
 801
 802         case MEMISLOCKED:
 803         {
 804                 struct erase_info_user einfo;
 805
 806                 if (copy_from_user(&einfo, argp, sizeof(einfo)))
 807                         return -EFAULT;
 808
 809                 ret = mtd_is_locked(mtd, einfo.start, einfo.length);
 810                 break;
 811         }
 812
 813         /* Legacy interface */
 814         case MEMGETOOBSEL:
 815         {
 816                 struct nand_oobinfo oi;
 817
 818                 if (!mtd->ecclayout)
 819                         return -EOPNOTSUPP;
 820                 if (mtd->ecclayout->eccbytes > ARRAY_SIZE(oi.eccpos))
 821                         return -EINVAL;
 822
 823                 oi.useecc = MTD_NANDECC_AUTOPLACE;
 824                 memcpy(&oi.eccpos, mtd->ecclayout->eccpos, sizeof(oi.eccpos));
 825                 memcpy(&oi.oobfree, mtd->ecclayout->oobfree,
 826                        sizeof(oi.oobfree));
 827                 oi.eccbytes = mtd->ecclayout->eccbytes;
 828
 829                 if (copy_to_user(argp, &oi, sizeof(struct nand_oobinfo)))
 830                         return -EFAULT;
 831                 break;
 832         }
 833
 834         case MEMGETBADBLOCK:
 835         {
 836                 loff_t offs;
 837
 838                 if (copy_from_user(&offs, argp, sizeof(loff_t)))
 839                         return -EFAULT;
 840                 return mtd_block_isbad(mtd, offs);
 841                 break;
 842         }
 843
 844         case MEMSETBADBLOCK:
 845         {
 846                 loff_t offs;
 847
 848                 if (copy_from_user(&offs, argp, sizeof(loff_t)))
 849                         return -EFAULT;
 850                 return mtd_block_markbad(mtd, offs);
 851                 break;
 852         }
 853
 854         case OTPSELECT:
 855         {
 856                 int mode;
 857                 if (copy_from_user(&mode, argp, sizeof(int)))
 858                         return -EFAULT;
 859
 860                 mfi->mode = MTD_FILE_MODE_NORMAL;
 861
 862                 ret = otp_select_filemode(mfi, mode);
 863
 864                 file->f_pos = 0;
 865                 break;
 866         }
 867
 868         case OTPGETREGIONCOUNT:
 869         case OTPGETREGIONINFO:
 870         {
 871                 struct otp_info *buf = kmalloc(4096, GFP_KERNEL);
 872                 size_t retlen;
 873                 if (!buf)
 874                         return -ENOMEM;
 875                 switch (mfi->mode) {
 876                 case MTD_FILE_MODE_OTP_FACTORY:
 877                         ret = mtd_get_fact_prot_info(mtd, 4096, &retlen, buf);
 878                         break;
 879                 case MTD_FILE_MODE_OTP_USER:
 880                         ret = mtd_get_user_prot_info(mtd, 4096, &retlen, buf);
 881                         break;
 882                 default:
 883                         ret = -EINVAL;
 884                         break;
 885                 }
 886                 if (!ret) {
 887                         if (cmd == OTPGETREGIONCOUNT) {
 888                                 int nbr = retlen / sizeof(struct otp_info);
 889                                 ret = copy_to_user(argp, &nbr, sizeof(int));
 890                         } else
 891                                 ret = copy_to_user(argp, buf, retlen);
 892                         if (ret)
 893                                 ret = -EFAULT;
 894                 }
 895                 kfree(buf);
 896                 break;
 897         }
 898
 899         case OTPLOCK:
 900         {
 901                 struct otp_info oinfo;
 902
 903                 if (mfi->mode != MTD_FILE_MODE_OTP_USER)
 904                         return -EINVAL;
 905                 if (copy_from_user(&oinfo, argp, sizeof(oinfo)))
 906                         return -EFAULT;
 907                 ret = mtd_lock_user_prot_reg(mtd, oinfo.start, oinfo.length);
 908                 break;
 909         }
 910
 911         /* This ioctl is being deprecated - it truncates the ECC layout */
 912         case ECCGETLAYOUT:
 913         {
 914                 struct nand_ecclayout_user *usrlay;
 915
 916                 if (!mtd->ecclayout)
 917                         return -EOPNOTSUPP;
 918
 919                 usrlay = kmalloc(sizeof(*usrlay), GFP_KERNEL);
 920                 if (!usrlay)
 921                         return -ENOMEM;
 922
 923                 shrink_ecclayout(mtd->ecclayout, usrlay);
 924
 925                 if (copy_to_user(argp, usrlay, sizeof(*usrlay)))
 926                         ret = -EFAULT;
 927                 kfree(usrlay);
 928                 break;
 929         }
 930
 931         case ECCGETSTATS:
 932         {
 933                 if (copy_to_user(argp, &mtd->ecc_stats,
 934                                  sizeof(struct mtd_ecc_stats)))
 935                         return -EFAULT;
 936                 break;
 937         }
 938
 939         case MTDFILEMODE:
 940         {
 941                 mfi->mode = 0;
 942
 943                 switch(arg) {
 944                 case MTD_FILE_MODE_OTP_FACTORY:
 945                 case MTD_FILE_MODE_OTP_USER:
 946                         ret = otp_select_filemode(mfi, arg);
 947                         break;
 948
 949                 case MTD_FILE_MODE_RAW:
 950                         if (!mtd_has_oob(mtd))
 951                                 return -EOPNOTSUPP;
 952                         mfi->mode = arg;
 953
 954                 case MTD_FILE_MODE_NORMAL:
 955                         break;
 956                 default:
 957                         ret = -EINVAL;
 958                 }
 959                 file->f_pos = 0;
 960                 break;
 961         }
 962
 963         case BLKPG:
 964         {
 965                 struct blkpg_ioctl_arg __user *blk_arg = argp;
 966                 struct blkpg_ioctl_arg a;
 967
 968                 if (copy_from_user(&a, blk_arg, sizeof(a)))
 969                         ret = -EFAULT;
 970                 else
 971                         ret = mtdchar_blkpg_ioctl(mtd, &a);
 972                 break;
 973         }
 974
 975         case BLKRRPART:
 976         {
 977                 /* No reread partition feature. Just return ok */
 978                 ret = 0;
 979                 break;
 980         }
 981
 982         default:
 983                 ret = -ENOTTY;
 984         }
 985
 986         return ret;
 987 } /* memory_ioctl */
 988
 989 static long mtdchar_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
 990 {
 991         int ret;
 992
 993         mutex_lock(&mtd_mutex);
 994         ret = mtdchar_ioctl(file, cmd, arg);
 995         mutex_unlock(&mtd_mutex);
 996
 997         return ret;
 998 }
 999
1000 #ifdef CONFIG_COMPAT
1001
1002 struct mtd_oob_buf32 {
1003         u_int32_t start;
1004         u_int32_t length;
1005         compat_caddr_t ptr;     /* unsigned char* */
1006 };
1007
1008 #define MEMWRITEOOB32           _IOWR('M', 3, struct mtd_oob_buf32)
1009 #define MEMREADOOB32            _IOWR('M', 4, struct mtd_oob_buf32)
1010
1011 static long mtdchar_compat_ioctl(struct file *file, unsigned int cmd,
1012         unsigned long arg)
1013 {
1014         struct mtd_file_info *mfi = file->private_data;
1015         struct mtd_info *mtd = mfi->mtd;
1016         void __user *argp = compat_ptr(arg);
1017         int ret = 0;
1018
1019         mutex_lock(&mtd_mutex);
1020
1021         switch (cmd) {
1022         case MEMWRITEOOB32:
1023         {
1024                 struct mtd_oob_buf32 buf;
1025                 struct mtd_oob_buf32 __user *buf_user = argp;
1026
1027                 if (copy_from_user(&buf, argp, sizeof(buf)))
1028                         ret = -EFAULT;
1029                 else
1030                         ret = mtdchar_writeoob(file, mtd, buf.start,
1031                                 buf.length, compat_ptr(buf.ptr),
1032                                 &buf_user->length);
1033                 break;
1034         }
1035
1036         case MEMREADOOB32:
1037         {
1038                 struct mtd_oob_buf32 buf;
1039                 struct mtd_oob_buf32 __user *buf_user = argp;
1040
1041                 /* NOTE: writes return length to buf->start */
1042                 if (copy_from_user(&buf, argp, sizeof(buf)))
1043                         ret = -EFAULT;
1044                 else
1045                         ret = mtdchar_readoob(file, mtd, buf.start,
1046                                 buf.length, compat_ptr(buf.ptr),
1047                                 &buf_user->start);
1048                 break;
1049         }
1050
1051         case BLKPG:
1052         {
1053                 /* Convert from blkpg_compat_ioctl_arg to blkpg_ioctl_arg */
1054                 struct blkpg_compat_ioctl_arg __user *uarg = argp;
1055                 struct blkpg_compat_ioctl_arg compat_arg;
1056                 struct blkpg_ioctl_arg a;
1057
1058                 if (copy_from_user(&compat_arg, uarg, sizeof(compat_arg))) {
1059                         ret = -EFAULT;
1060                         break;
1061                 }
1062
1063                 memset(&a, 0, sizeof(a));
1064                 a.op = compat_arg.op;
1065                 a.flags = compat_arg.flags;
1066                 a.datalen = compat_arg.datalen;
1067                 a.data = compat_ptr(compat_arg.data);
1068
1069                 ret = mtdchar_blkpg_ioctl(mtd, &a);
1070                 break;
1071         }
1072
1073         default:
1074                 ret = mtdchar_ioctl(file, cmd, (unsigned long)argp);
1075         }
1076
1077         mutex_unlock(&mtd_mutex);
1078
1079         return ret;
1080 }
1081
1082 #endif /* CONFIG_COMPAT */
1083
1084 /*
1085  * try to determine where a shared mapping can be made
1086  * - only supported for NOMMU at the moment (MMU can't doesn't copy private
1087  *   mappings)
1088  */
1089 #ifndef CONFIG_MMU
1090 static unsigned long mtdchar_get_unmapped_area(struct file *file,
1091                                            unsigned long addr,
1092                                            unsigned long len,
1093                                            unsigned long pgoff,
1094                                            unsigned long flags)
1095 {
1096         struct mtd_file_info *mfi = file->private_data;
1097         struct mtd_info *mtd = mfi->mtd;
1098         unsigned long offset;
1099         int ret;
1100
1101         if (addr != 0)
1102                 return (unsigned long) -EINVAL;
1103
1104         if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT))
1105                 return (unsigned long) -EINVAL;
1106
1107         offset = pgoff << PAGE_SHIFT;
1108         if (offset > mtd->size - len)
1109                 return (unsigned long) -EINVAL;
1110
1111         ret = mtd_get_unmapped_area(mtd, len, offset, flags);
1112         return ret == -EOPNOTSUPP ? -ENODEV : ret;
1113 }
1114
1115 static unsigned mtdchar_mmap_capabilities(struct file *file)
1116 {
1117         struct mtd_file_info *mfi = file->private_data;
1118
1119         return mtd_mmap_capabilities(mfi->mtd);
1120 }
1121 #endif
1122
1123 /*
1124  * set up a mapping for shared memory segments
1125  */
1126 static int mtdchar_mmap(struct file *file, struct vm_area_struct *vma)
1127 {
1128 #ifdef CONFIG_MMU
1129         struct mtd_file_info *mfi = file->private_data;
1130         struct mtd_info *mtd = mfi->mtd;
1131         struct map_info *map = mtd->priv;
1132
1133         /* This is broken because it assumes the MTD device is map-based
1134            and that mtd->priv is a valid struct map_info.  It should be
1135            replaced with something that uses the mtd_get_unmapped_area()
1136            operation properly. */
1137         if (0 /*mtd->type == MTD_RAM || mtd->type == MTD_ROM*/) {
1138 #ifdef pgprot_noncached
1139                 if (file->f_flags & O_DSYNC || map->phys >= __pa(high_memory))
1140                         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1141 #endif
1142                 return vm_iomap_memory(vma, map->phys, map->size);
1143         }
1144         return -ENODEV;
1145 #else
1146         return vma->vm_flags & VM_SHARED ? 0 : -EACCES;
1147 #endif
1148 }
1149
1150 static const struct file_operations mtd_fops = {
1151         .owner          = THIS_MODULE,
1152         .llseek         = mtdchar_lseek,
1153         .read           = mtdchar_read,
1154         .write          = mtdchar_write,
1155         .unlocked_ioctl = mtdchar_unlocked_ioctl,
1156 #ifdef CONFIG_COMPAT
1157         .compat_ioctl   = mtdchar_compat_ioctl,
1158 #endif
1159         .open           = mtdchar_open,
1160         .release        = mtdchar_close,
1161         .mmap           = mtdchar_mmap,
1162 #ifndef CONFIG_MMU
1163         .get_unmapped_area = mtdchar_get_unmapped_area,
1164         .mmap_capabilities = mtdchar_mmap_capabilities,
1165 #endif
1166 };
1167
1168 int __init init_mtdchar(void)
1169 {
1170         int ret;
1171
1172         ret = __register_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS,
1173                                    "mtd", &mtd_fops);
1174         if (ret < 0) {
1175                 pr_err("Can't allocate major number %d for MTD\n",
1176                        MTD_CHAR_MAJOR);
1177                 return ret;
1178         }
1179
1180         return ret;
1181 }
1182
1183 void __exit cleanup_mtdchar(void)
1184 {
1185         __unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1186 }
1187
1188 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);