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   1 /*
   2  * $Id: mtdchar.c,v 1.66 2005/01/05 18:05:11 dwmw2 Exp $
   3  *
   4  * Character-device access to raw MTD devices.
   5  *
   6  */
   7
   8 #include <linux/config.h>
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/mtd/mtd.h>
  12 #include <linux/mtd/compatmac.h>
  13 #include <linux/slab.h>
  14 #include <linux/init.h>
  15 #include <linux/fs.h>
  16 #include <asm/uaccess.h>
  17
  18 #ifdef CONFIG_DEVFS_FS
  19 #include <linux/devfs_fs_kernel.h>
  20
  21 static void mtd_notify_add(struct mtd_info* mtd)
  22 {
  23         if (!mtd)
  24                 return;
  25
  26         devfs_mk_cdev(MKDEV(MTD_CHAR_MAJOR, mtd->index*2),
  27                       S_IFCHR | S_IRUGO | S_IWUGO, "mtd/%d", mtd->index);
  28
  29         devfs_mk_cdev(MKDEV(MTD_CHAR_MAJOR, mtd->index*2+1),
  30                       S_IFCHR | S_IRUGO, "mtd/%dro", mtd->index);
  31 }
  32
  33 static void mtd_notify_remove(struct mtd_info* mtd)
  34 {
  35         if (!mtd)
  36                 return;
  37         devfs_remove("mtd/%d", mtd->index);
  38         devfs_remove("mtd/%dro", mtd->index);
  39 }
  40
  41 static struct mtd_notifier notifier = {
  42         .add    = mtd_notify_add,
  43         .remove = mtd_notify_remove,
  44 };
  45
  46 static inline void mtdchar_devfs_init(void)
  47 {
  48         devfs_mk_dir("mtd");
  49         register_mtd_user(&notifier);
  50 }
  51
  52 static inline void mtdchar_devfs_exit(void)
  53 {
  54         unregister_mtd_user(&notifier);
  55         devfs_remove("mtd");
  56 }
  57 #else /* !DEVFS */
  58 #define mtdchar_devfs_init() do { } while(0)
  59 #define mtdchar_devfs_exit() do { } while(0)
  60 #endif
  61
  62 static loff_t mtd_lseek (struct file *file, loff_t offset, int orig)
  63 {
  64         struct mtd_info *mtd = file->private_data;
  65
  66         switch (orig) {
  67         case 0:
  68                 /* SEEK_SET */
  69                 file->f_pos = offset;
  70                 break;
  71         case 1:
  72                 /* SEEK_CUR */
  73                 file->f_pos += offset;
  74                 break;
  75         case 2:
  76                 /* SEEK_END */
  77                 file->f_pos =mtd->size + offset;
  78                 break;
  79         default:
  80                 return -EINVAL;
  81         }
  82
  83         if (file->f_pos < 0)
  84                 file->f_pos = 0;
  85         else if (file->f_pos >= mtd->size)
  86                 file->f_pos = mtd->size - 1;
  87
  88         return file->f_pos;
  89 }
  90
  91
  92
  93 static int mtd_open(struct inode *inode, struct file *file)
  94 {
  95         int minor = iminor(inode);
  96         int devnum = minor >> 1;
  97         struct mtd_info *mtd;
  98
  99         DEBUG(MTD_DEBUG_LEVEL0, "MTD_open\n");
 100
 101         if (devnum >= MAX_MTD_DEVICES)
 102                 return -ENODEV;
 103
 104         /* You can't open the RO devices RW */
 105         if ((file->f_mode & 2) && (minor & 1))
 106                 return -EACCES;
 107
 108         mtd = get_mtd_device(NULL, devnum);
 109
 110         if (!mtd)
 111                 return -ENODEV;
 112
 113         if (MTD_ABSENT == mtd->type) {
 114                 put_mtd_device(mtd);
 115                 return -ENODEV;
 116         }
 117
 118         file->private_data = mtd;
 119
 120         /* You can't open it RW if it's not a writeable device */
 121         if ((file->f_mode & 2) && !(mtd->flags & MTD_WRITEABLE)) {
 122                 put_mtd_device(mtd);
 123                 return -EACCES;
 124         }
 125
 126         return 0;
 127 } /* mtd_open */
 128
 129 /*====================================================================*/
 130
 131 static int mtd_close(struct inode *inode, struct file *file)
 132 {
 133         struct mtd_info *mtd;
 134
 135         DEBUG(MTD_DEBUG_LEVEL0, "MTD_close\n");
 136
 137         mtd = file->private_data;
 138
 139         if (mtd->sync)
 140                 mtd->sync(mtd);
 141
 142         put_mtd_device(mtd);
 143
 144         return 0;
 145 } /* mtd_close */
 146
 147 /* FIXME: This _really_ needs to die. In 2.5, we should lock the
 148    userspace buffer down and use it directly with readv/writev.
 149 */
 150 #define MAX_KMALLOC_SIZE 0x20000
 151
 152 static ssize_t mtd_read(struct file *file, char __user *buf, size_t count,loff_t *ppos)
 153 {
 154         struct mtd_info *mtd = file->private_data;
 155         size_t retlen=0;
 156         size_t total_retlen=0;
 157         int ret=0;
 158         int len;
 159         char *kbuf;
 160
 161         DEBUG(MTD_DEBUG_LEVEL0,"MTD_read\n");
 162
 163         if (*ppos + count > mtd->size)
 164                 count = mtd->size - *ppos;
 165
 166         if (!count)
 167                 return 0;
 168
 169         /* FIXME: Use kiovec in 2.5 to lock down the user's buffers
 170            and pass them directly to the MTD functions */
 171         while (count) {
 172                 if (count > MAX_KMALLOC_SIZE)
 173                         len = MAX_KMALLOC_SIZE;
 174                 else
 175                         len = count;
 176
 177                 kbuf=kmalloc(len,GFP_KERNEL);
 178                 if (!kbuf)
 179                         return -ENOMEM;
 180
 181                 ret = MTD_READ(mtd, *ppos, len, &retlen, kbuf);
 182                 /* Nand returns -EBADMSG on ecc errors, but it returns
 183                  * the data. For our userspace tools it is important
 184                  * to dump areas with ecc errors !
 185                  * Userspace software which accesses NAND this way
 186                  * must be aware of the fact that it deals with NAND
 187                  */
 188                 if (!ret || (ret == -EBADMSG)) {
 189                         *ppos += retlen;
 190                         if (copy_to_user(buf, kbuf, retlen)) {
 191                                 kfree(kbuf);
 192                                 return -EFAULT;
 193                         }
 194                         else
 195                                 total_retlen += retlen;
 196
 197                         count -= retlen;
 198                         buf += retlen;
 199                 }
 200                 else {
 201                         kfree(kbuf);
 202                         return ret;
 203                 }
 204
 205                 kfree(kbuf);
 206         }
 207
 208         return total_retlen;
 209 } /* mtd_read */
 210
 211 static ssize_t mtd_write(struct file *file, const char __user *buf, size_t count,loff_t *ppos)
 212 {
 213         struct mtd_info *mtd = file->private_data;
 214         char *kbuf;
 215         size_t retlen;
 216         size_t total_retlen=0;
 217         int ret=0;
 218         int len;
 219
 220         DEBUG(MTD_DEBUG_LEVEL0,"MTD_write\n");
 221
 222         if (*ppos == mtd->size)
 223                 return -ENOSPC;
 224
 225         if (*ppos + count > mtd->size)
 226                 count = mtd->size - *ppos;
 227
 228         if (!count)
 229                 return 0;
 230
 231         while (count) {
 232                 if (count > MAX_KMALLOC_SIZE)
 233                         len = MAX_KMALLOC_SIZE;
 234                 else
 235                         len = count;
 236
 237                 kbuf=kmalloc(len,GFP_KERNEL);
 238                 if (!kbuf) {
 239                         printk("kmalloc is null\n");
 240                         return -ENOMEM;
 241                 }
 242
 243                 if (copy_from_user(kbuf, buf, len)) {
 244                         kfree(kbuf);
 245                         return -EFAULT;
 246                 }
 247
 248                 ret = (*(mtd->write))(mtd, *ppos, len, &retlen, kbuf);
 249                 if (!ret) {
 250                         *ppos += retlen;
 251                         total_retlen += retlen;
 252                         count -= retlen;
 253                         buf += retlen;
 254                 }
 255                 else {
 256                         kfree(kbuf);
 257                         return ret;
 258                 }
 259
 260                 kfree(kbuf);
 261         }
 262
 263         return total_retlen;
 264 } /* mtd_write */
 265
 266 /*======================================================================
 267
 268     IOCTL calls for getting device parameters.
 269
 270 ======================================================================*/
 271 static void mtdchar_erase_callback (struct erase_info *instr)
 272 {
 273         wake_up((wait_queue_head_t *)instr->priv);
 274 }
 275
 276 static int mtd_ioctl(struct inode *inode, struct file *file,
 277                      u_int cmd, u_long arg)
 278 {
 279         struct mtd_info *mtd = file->private_data;
 280         void __user *argp = (void __user *)arg;
 281         int ret = 0;
 282         u_long size;
 283
 284         DEBUG(MTD_DEBUG_LEVEL0, "MTD_ioctl\n");
 285
 286         size = (cmd & IOCSIZE_MASK) >> IOCSIZE_SHIFT;
 287         if (cmd & IOC_IN) {
 288                 if (!access_ok(VERIFY_READ, argp, size))
 289                         return -EFAULT;
 290         }
 291         if (cmd & IOC_OUT) {
 292                 if (!access_ok(VERIFY_WRITE, argp, size))
 293                         return -EFAULT;
 294         }
 295
 296         switch (cmd) {
 297         case MEMGETREGIONCOUNT:
 298                 if (copy_to_user(argp, &(mtd->numeraseregions), sizeof(int)))
 299                         return -EFAULT;
 300                 break;
 301
 302         case MEMGETREGIONINFO:
 303         {
 304                 struct region_info_user ur;
 305
 306                 if (copy_from_user(&ur, argp, sizeof(struct region_info_user)))
 307                         return -EFAULT;
 308
 309                 if (ur.regionindex >= mtd->numeraseregions)
 310                         return -EINVAL;
 311                 if (copy_to_user(argp, &(mtd->eraseregions[ur.regionindex]),
 312                                 sizeof(struct mtd_erase_region_info)))
 313                         return -EFAULT;
 314                 break;
 315         }
 316
 317         case MEMGETINFO:
 318                 if (copy_to_user(argp, mtd, sizeof(struct mtd_info_user)))
 319                         return -EFAULT;
 320                 break;
 321
 322         case MEMERASE:
 323         {
 324                 struct erase_info *erase;
 325
 326                 if(!(file->f_mode & 2))
 327                         return -EPERM;
 328
 329                 erase=kmalloc(sizeof(struct erase_info),GFP_KERNEL);
 330                 if (!erase)
 331                         ret = -ENOMEM;
 332                 else {
 333                         wait_queue_head_t waitq;
 334                         DECLARE_WAITQUEUE(wait, current);
 335
 336                         init_waitqueue_head(&waitq);
 337
 338                         memset (erase,0,sizeof(struct erase_info));
 339                         if (copy_from_user(&erase->addr, argp,
 340                                     sizeof(struct erase_info_user))) {
 341                                 kfree(erase);
 342                                 return -EFAULT;
 343                         }
 344                         erase->mtd = mtd;
 345                         erase->callback = mtdchar_erase_callback;
 346                         erase->priv = (unsigned long)&waitq;
 347
 348                         /*
 349                           FIXME: Allow INTERRUPTIBLE. Which means
 350                           not having the wait_queue head on the stack.
 351
 352                           If the wq_head is on the stack, and we
 353                           leave because we got interrupted, then the
 354                           wq_head is no longer there when the
 355                           callback routine tries to wake us up.
 356                         */
 357                         ret = mtd->erase(mtd, erase);
 358                         if (!ret) {
 359                                 set_current_state(TASK_UNINTERRUPTIBLE);
 360                                 add_wait_queue(&waitq, &wait);
 361                                 if (erase->state != MTD_ERASE_DONE &&
 362                                     erase->state != MTD_ERASE_FAILED)
 363                                         schedule();
 364                                 remove_wait_queue(&waitq, &wait);
 365                                 set_current_state(TASK_RUNNING);
 366
 367                                 ret = (erase->state == MTD_ERASE_FAILED)?-EIO:0;
 368                         }
 369                         kfree(erase);
 370                 }
 371                 break;
 372         }
 373
 374         case MEMWRITEOOB:
 375         {
 376                 struct mtd_oob_buf buf;
 377                 void *databuf;
 378                 ssize_t retlen;
 379
 380                 if(!(file->f_mode & 2))
 381                         return -EPERM;
 382
 383                 if (copy_from_user(&buf, argp, sizeof(struct mtd_oob_buf)))
 384                         return -EFAULT;
 385
 386                 if (buf.length > 0x4096)
 387                         return -EINVAL;
 388
 389                 if (!mtd->write_oob)
 390                         ret = -EOPNOTSUPP;
 391                 else
 392                         ret = access_ok(VERIFY_READ, buf.ptr,
 393                                         buf.length) ? 0 : EFAULT;
 394
 395                 if (ret)
 396                         return ret;
 397
 398                 databuf = kmalloc(buf.length, GFP_KERNEL);
 399                 if (!databuf)
 400                         return -ENOMEM;
 401
 402                 if (copy_from_user(databuf, buf.ptr, buf.length)) {
 403                         kfree(databuf);
 404                         return -EFAULT;
 405                 }
 406
 407                 ret = (mtd->write_oob)(mtd, buf.start, buf.length, &retlen, databuf);
 408
 409                 if (copy_to_user(argp + sizeof(uint32_t), &retlen, sizeof(uint32_t)))
 410                         ret = -EFAULT;
 411
 412                 kfree(databuf);
 413                 break;
 414
 415         }
 416
 417         case MEMREADOOB:
 418         {
 419                 struct mtd_oob_buf buf;
 420                 void *databuf;
 421                 ssize_t retlen;
 422
 423                 if (copy_from_user(&buf, argp, sizeof(struct mtd_oob_buf)))
 424                         return -EFAULT;
 425
 426                 if (buf.length > 0x4096)
 427                         return -EINVAL;
 428
 429                 if (!mtd->read_oob)
 430                         ret = -EOPNOTSUPP;
 431                 else
 432                         ret = access_ok(VERIFY_WRITE, buf.ptr,
 433                                         buf.length) ? 0 : -EFAULT;
 434
 435                 if (ret)
 436                         return ret;
 437
 438                 databuf = kmalloc(buf.length, GFP_KERNEL);
 439                 if (!databuf)
 440                         return -ENOMEM;
 441
 442                 ret = (mtd->read_oob)(mtd, buf.start, buf.length, &retlen, databuf);
 443
 444                 if (put_user(retlen, (uint32_t __user *)argp))
 445                         ret = -EFAULT;
 446                 else if (retlen && copy_to_user(buf.ptr, databuf, retlen))
 447                         ret = -EFAULT;
 448
 449                 kfree(databuf);
 450                 break;
 451         }
 452
 453         case MEMLOCK:
 454         {
 455                 struct erase_info_user info;
 456
 457                 if (copy_from_user(&info, argp, sizeof(info)))
 458                         return -EFAULT;
 459
 460                 if (!mtd->lock)
 461                         ret = -EOPNOTSUPP;
 462                 else
 463                         ret = mtd->lock(mtd, info.start, info.length);
 464                 break;
 465         }
 466
 467         case MEMUNLOCK:
 468         {
 469                 struct erase_info_user info;
 470
 471                 if (copy_from_user(&info, argp, sizeof(info)))
 472                         return -EFAULT;
 473
 474                 if (!mtd->unlock)
 475                         ret = -EOPNOTSUPP;
 476                 else
 477                         ret = mtd->unlock(mtd, info.start, info.length);
 478                 break;
 479         }
 480
 481         case MEMSETOOBSEL:
 482         {
 483                 if (copy_from_user(&mtd->oobinfo, argp, sizeof(struct nand_oobinfo)))
 484                         return -EFAULT;
 485                 break;
 486         }
 487
 488         case MEMGETOOBSEL:
 489         {
 490                 if (copy_to_user(argp, &(mtd->oobinfo), sizeof(struct nand_oobinfo)))
 491                         return -EFAULT;
 492                 break;
 493         }
 494
 495         case MEMGETBADBLOCK:
 496         {
 497                 loff_t offs;
 498
 499                 if (copy_from_user(&offs, argp, sizeof(loff_t)))
 500                         return -EFAULT;
 501                 if (!mtd->block_isbad)
 502                         ret = -EOPNOTSUPP;
 503                 else
 504                         return mtd->block_isbad(mtd, offs);
 505                 break;
 506         }
 507
 508         case MEMSETBADBLOCK:
 509         {
 510                 loff_t offs;
 511
 512                 if (copy_from_user(&offs, argp, sizeof(loff_t)))
 513                         return -EFAULT;
 514                 if (!mtd->block_markbad)
 515                         ret = -EOPNOTSUPP;
 516                 else
 517                         return mtd->block_markbad(mtd, offs);
 518                 break;
 519         }
 520
 521         default:
 522                 ret = -ENOTTY;
 523         }
 524
 525         return ret;
 526 } /* memory_ioctl */
 527
 528 static struct file_operations mtd_fops = {
 529         .owner          = THIS_MODULE,
 530         .llseek         = mtd_lseek,
 531         .read           = mtd_read,
 532         .write          = mtd_write,
 533         .ioctl          = mtd_ioctl,
 534         .open           = mtd_open,
 535         .release        = mtd_close,
 536 };
 537
 538 static int __init init_mtdchar(void)
 539 {
 540         if (register_chrdev(MTD_CHAR_MAJOR, "mtd", &mtd_fops)) {
 541                 printk(KERN_NOTICE "Can't allocate major number %d for Memory Technology Devices.\n",
 542                        MTD_CHAR_MAJOR);
 543                 return -EAGAIN;
 544         }
 545
 546         mtdchar_devfs_init();
 547         return 0;
 548 }
 549
 550 static void __exit cleanup_mtdchar(void)
 551 {
 552         mtdchar_devfs_exit();
 553         unregister_chrdev(MTD_CHAR_MAJOR, "mtd");
 554 }
 555
 556 module_init(init_mtdchar);
 557 module_exit(cleanup_mtdchar);
 558
 559
 560 MODULE_LICENSE("GPL");
 561 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 562 MODULE_DESCRIPTION("Direct character-device access to MTD devices");