drivers/mtd/mtdchar.c

   1 /*
   2  * $Id: mtdchar.c,v 1.54 2003/05/21 10:50:43 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/slab.h>
  13 #include <linux/init.h>
  14 #include <linux/fs.h>
  15 #include <asm/uaccess.h>
  16
  17 #ifdef CONFIG_DEVFS_FS
  18 #include <linux/devfs_fs_kernel.h>
  19 static void mtd_notify_add(struct mtd_info* mtd);
  20 static void mtd_notify_remove(struct mtd_info* mtd);
  21
  22 static struct mtd_notifier notifier = {
  23         .add    = mtd_notify_add,
  24         .remove = mtd_notify_remove,
  25 };
  26
  27 #endif
  28
  29 static loff_t mtd_lseek (struct file *file, loff_t offset, int orig)
  30 {
  31         struct mtd_info *mtd=(struct mtd_info *)file->private_data;
  32
  33         switch (orig) {
  34         case 0:
  35                 /* SEEK_SET */
  36                 file->f_pos = offset;
  37                 break;
  38         case 1:
  39                 /* SEEK_CUR */
  40                 file->f_pos += offset;
  41                 break;
  42         case 2:
  43                 /* SEEK_END */
  44                 file->f_pos =mtd->size + offset;
  45                 break;
  46         default:
  47                 return -EINVAL;
  48         }
  49
  50         if (file->f_pos < 0)
  51                 file->f_pos = 0;
  52         else if (file->f_pos >= mtd->size)
  53                 file->f_pos = mtd->size - 1;
  54
  55         return file->f_pos;
  56 }
  57
  58
  59
  60 static int mtd_open(struct inode *inode, struct file *file)
  61 {
  62         int minor = iminor(inode);
  63         int devnum = minor >> 1;
  64         struct mtd_info *mtd;
  65
  66         DEBUG(MTD_DEBUG_LEVEL0, "MTD_open\n");
  67
  68         if (devnum >= MAX_MTD_DEVICES)
  69                 return -ENODEV;
  70
  71         /* You can't open the RO devices RW */
  72         if ((file->f_mode & 2) && (minor & 1))
  73                 return -EACCES;
  74
  75         mtd = get_mtd_device(NULL, devnum);
  76
  77         if (!mtd)
  78                 return -ENODEV;
  79
  80         if (MTD_ABSENT == mtd->type) {
  81                 put_mtd_device(mtd);
  82                 return -ENODEV;
  83         }
  84
  85         file->private_data = mtd;
  86
  87         /* You can't open it RW if it's not a writeable device */
  88         if ((file->f_mode & 2) && !(mtd->flags & MTD_WRITEABLE)) {
  89                 put_mtd_device(mtd);
  90                 return -EACCES;
  91         }
  92
  93         return 0;
  94 } /* mtd_open */
  95
  96 /*====================================================================*/
  97
  98 static int mtd_close(struct inode *inode, struct file *file)
  99 {
 100         struct mtd_info *mtd;
 101
 102         DEBUG(MTD_DEBUG_LEVEL0, "MTD_close\n");
 103
 104         mtd = (struct mtd_info *)file->private_data;
 105
 106         if (mtd->sync)
 107                 mtd->sync(mtd);
 108
 109         put_mtd_device(mtd);
 110
 111         return 0;
 112 } /* mtd_close */
 113
 114 /* FIXME: This _really_ needs to die. In 2.5, we should lock the
 115    userspace buffer down and use it directly with readv/writev.
 116 */
 117 #define MAX_KMALLOC_SIZE 0x20000
 118
 119 static ssize_t mtd_read(struct file *file, char *buf, size_t count,loff_t *ppos)
 120 {
 121         struct mtd_info *mtd = (struct mtd_info *)file->private_data;
 122         size_t retlen=0;
 123         size_t total_retlen=0;
 124         int ret=0;
 125         int len;
 126         char *kbuf;
 127
 128         DEBUG(MTD_DEBUG_LEVEL0,"MTD_read\n");
 129
 130         if (*ppos + count > mtd->size)
 131                 count = mtd->size - *ppos;
 132
 133         if (!count)
 134                 return 0;
 135
 136         /* FIXME: Use kiovec in 2.5 to lock down the user's buffers
 137            and pass them directly to the MTD functions */
 138         while (count) {
 139                 if (count > MAX_KMALLOC_SIZE)
 140                         len = MAX_KMALLOC_SIZE;
 141                 else
 142                         len = count;
 143
 144                 kbuf=kmalloc(len,GFP_KERNEL);
 145                 if (!kbuf)
 146                         return -ENOMEM;
 147
 148                 ret = MTD_READ(mtd, *ppos, len, &retlen, kbuf);
 149                 if (!ret) {
 150                         *ppos += retlen;
 151                         if (copy_to_user(buf, kbuf, retlen)) {
 152                                 kfree(kbuf);
 153                                 return -EFAULT;
 154                         }
 155                         else
 156                                 total_retlen += retlen;
 157
 158                         count -= retlen;
 159                         buf += retlen;
 160                 }
 161                 else {
 162                         kfree(kbuf);
 163                         return ret;
 164                 }
 165
 166                 kfree(kbuf);
 167         }
 168
 169         return total_retlen;
 170 } /* mtd_read */
 171
 172 static ssize_t mtd_write(struct file *file, const char *buf, size_t count,loff_t *ppos)
 173 {
 174         struct mtd_info *mtd = (struct mtd_info *)file->private_data;
 175         char *kbuf;
 176         size_t retlen;
 177         size_t total_retlen=0;
 178         int ret=0;
 179         int len;
 180
 181         DEBUG(MTD_DEBUG_LEVEL0,"MTD_write\n");
 182
 183         if (*ppos == mtd->size)
 184                 return -ENOSPC;
 185
 186         if (*ppos + count > mtd->size)
 187                 count = mtd->size - *ppos;
 188
 189         if (!count)
 190                 return 0;
 191
 192         while (count) {
 193                 if (count > MAX_KMALLOC_SIZE)
 194                         len = MAX_KMALLOC_SIZE;
 195                 else
 196                         len = count;
 197
 198                 kbuf=kmalloc(len,GFP_KERNEL);
 199                 if (!kbuf) {
 200                         printk("kmalloc is null\n");
 201                         return -ENOMEM;
 202                 }
 203
 204                 if (copy_from_user(kbuf, buf, len)) {
 205                         kfree(kbuf);
 206                         return -EFAULT;
 207                 }
 208
 209                 ret = (*(mtd->write))(mtd, *ppos, len, &retlen, kbuf);
 210                 if (!ret) {
 211                         *ppos += retlen;
 212                         total_retlen += retlen;
 213                         count -= retlen;
 214                         buf += retlen;
 215                 }
 216                 else {
 217                         kfree(kbuf);
 218                         return ret;
 219                 }
 220
 221                 kfree(kbuf);
 222         }
 223
 224         return total_retlen;
 225 } /* mtd_write */
 226
 227 /*======================================================================
 228
 229     IOCTL calls for getting device parameters.
 230
 231 ======================================================================*/
 232 static void mtd_erase_callback (struct erase_info *instr)
 233 {
 234         wake_up((wait_queue_head_t *)instr->priv);
 235 }
 236
 237 static int mtd_ioctl(struct inode *inode, struct file *file,
 238                      u_int cmd, u_long arg)
 239 {
 240         struct mtd_info *mtd = (struct mtd_info *)file->private_data;
 241         int ret = 0;
 242         u_long size;
 243
 244         DEBUG(MTD_DEBUG_LEVEL0, "MTD_ioctl\n");
 245
 246         size = (cmd & IOCSIZE_MASK) >> IOCSIZE_SHIFT;
 247         if (cmd & IOC_IN) {
 248                 ret = verify_area(VERIFY_READ, (char *)arg, size);
 249                 if (ret) return ret;
 250         }
 251         if (cmd & IOC_OUT) {
 252                 ret = verify_area(VERIFY_WRITE, (char *)arg, size);
 253                 if (ret) return ret;
 254         }
 255
 256         switch (cmd) {
 257         case MEMGETREGIONCOUNT:
 258                 if (copy_to_user((int *) arg, &(mtd->numeraseregions), sizeof(int)))
 259                         return -EFAULT;
 260                 break;
 261
 262         case MEMGETREGIONINFO:
 263         {
 264                 struct region_info_user ur;
 265
 266                 if (copy_from_user(     &ur,
 267                                         (struct region_info_user *)arg,
 268                                         sizeof(struct region_info_user))) {
 269                         return -EFAULT;
 270                 }
 271
 272                 if (ur.regionindex >= mtd->numeraseregions)
 273                         return -EINVAL;
 274                 if (copy_to_user((struct mtd_erase_region_info *) arg,
 275                                 &(mtd->eraseregions[ur.regionindex]),
 276                                 sizeof(struct mtd_erase_region_info)))
 277                         return -EFAULT;
 278                 break;
 279         }
 280
 281         case MEMGETINFO:
 282                 if (copy_to_user((struct mtd_info *)arg, mtd,
 283                                  sizeof(struct mtd_info_user)))
 284                         return -EFAULT;
 285                 break;
 286
 287         case MEMERASE:
 288         {
 289                 struct erase_info *erase;
 290
 291                 if(!(file->f_mode & 2))
 292                         return -EPERM;
 293
 294                 erase=kmalloc(sizeof(struct erase_info),GFP_KERNEL);
 295                 if (!erase)
 296                         ret = -ENOMEM;
 297                 else {
 298                         wait_queue_head_t waitq;
 299                         DECLARE_WAITQUEUE(wait, current);
 300
 301                         init_waitqueue_head(&waitq);
 302
 303                         memset (erase,0,sizeof(struct erase_info));
 304                         if (copy_from_user(&erase->addr, (u_long *)arg,
 305                                            2 * sizeof(u_long))) {
 306                                 kfree(erase);
 307                                 return -EFAULT;
 308                         }
 309                         erase->mtd = mtd;
 310                         erase->callback = mtd_erase_callback;
 311                         erase->priv = (unsigned long)&waitq;
 312
 313                         /*
 314                           FIXME: Allow INTERRUPTIBLE. Which means
 315                           not having the wait_queue head on the stack.
 316
 317                           If the wq_head is on the stack, and we
 318                           leave because we got interrupted, then the
 319                           wq_head is no longer there when the
 320                           callback routine tries to wake us up.
 321                         */
 322                         ret = mtd->erase(mtd, erase);
 323                         if (!ret) {
 324                                 set_current_state(TASK_UNINTERRUPTIBLE);
 325                                 add_wait_queue(&waitq, &wait);
 326                                 if (erase->state != MTD_ERASE_DONE &&
 327                                     erase->state != MTD_ERASE_FAILED)
 328                                         schedule();
 329                                 remove_wait_queue(&waitq, &wait);
 330                                 set_current_state(TASK_RUNNING);
 331
 332                                 ret = (erase->state == MTD_ERASE_FAILED)?-EIO:0;
 333                         }
 334                         kfree(erase);
 335                 }
 336                 break;
 337         }
 338
 339         case MEMWRITEOOB:
 340         {
 341                 struct mtd_oob_buf buf;
 342                 void *databuf;
 343                 ssize_t retlen;
 344
 345                 if(!(file->f_mode & 2))
 346                         return -EPERM;
 347
 348                 if (copy_from_user(&buf, (struct mtd_oob_buf *)arg, sizeof(struct mtd_oob_buf)))
 349                         return -EFAULT;
 350
 351                 if (buf.length > 0x4096)
 352                         return -EINVAL;
 353
 354                 if (!mtd->write_oob)
 355                         ret = -EOPNOTSUPP;
 356                 else
 357                         ret = verify_area(VERIFY_READ, (char *)buf.ptr, buf.length);
 358
 359                 if (ret)
 360                         return ret;
 361
 362                 databuf = kmalloc(buf.length, GFP_KERNEL);
 363                 if (!databuf)
 364                         return -ENOMEM;
 365
 366                 if (copy_from_user(databuf, buf.ptr, buf.length)) {
 367                         kfree(databuf);
 368                         return -EFAULT;
 369                 }
 370
 371                 ret = (mtd->write_oob)(mtd, buf.start, buf.length, &retlen, databuf);
 372
 373                 if (copy_to_user((void *)arg + sizeof(u_int32_t), &retlen, sizeof(u_int32_t)))
 374                         ret = -EFAULT;
 375
 376                 kfree(databuf);
 377                 break;
 378
 379         }
 380
 381         case MEMREADOOB:
 382         {
 383                 struct mtd_oob_buf buf;
 384                 void *databuf;
 385                 ssize_t retlen;
 386
 387                 if (copy_from_user(&buf, (struct mtd_oob_buf *)arg, sizeof(struct mtd_oob_buf)))
 388                         return -EFAULT;
 389
 390                 if (buf.length > 0x4096)
 391                         return -EINVAL;
 392
 393                 if (!mtd->read_oob)
 394                         ret = -EOPNOTSUPP;
 395                 else
 396                         ret = verify_area(VERIFY_WRITE, (char *)buf.ptr, buf.length);
 397
 398                 if (ret)
 399                         return ret;
 400
 401                 databuf = kmalloc(buf.length, GFP_KERNEL);
 402                 if (!databuf)
 403                         return -ENOMEM;
 404
 405                 ret = (mtd->read_oob)(mtd, buf.start, buf.length, &retlen, databuf);
 406
 407                 if (copy_to_user((void *)arg + sizeof(u_int32_t), &retlen, sizeof(u_int32_t)))
 408                         ret = -EFAULT;
 409                 else if (retlen && copy_to_user(buf.ptr, databuf, retlen))
 410                         ret = -EFAULT;
 411
 412                 kfree(databuf);
 413                 break;
 414         }
 415
 416         case MEMLOCK:
 417         {
 418                 unsigned long adrs[2];
 419
 420                 if (copy_from_user(adrs ,(void *)arg, 2* sizeof(unsigned long)))
 421                         return -EFAULT;
 422
 423                 if (!mtd->lock)
 424                         ret = -EOPNOTSUPP;
 425                 else
 426                         ret = mtd->lock(mtd, adrs[0], adrs[1]);
 427                 break;
 428         }
 429
 430         case MEMUNLOCK:
 431         {
 432                 unsigned long adrs[2];
 433
 434                 if (copy_from_user(adrs, (void *)arg, 2* sizeof(unsigned long)))
 435                         return -EFAULT;
 436
 437                 if (!mtd->unlock)
 438                         ret = -EOPNOTSUPP;
 439                 else
 440                         ret = mtd->unlock(mtd, adrs[0], adrs[1]);
 441                 break;
 442         }
 443
 444         case MEMSETOOBSEL:
 445         {
 446                 if (copy_from_user(&mtd->oobinfo ,(void *)arg, sizeof(struct nand_oobinfo)))
 447                         return -EFAULT;
 448                 break;
 449         }
 450
 451         default:
 452                 DEBUG(MTD_DEBUG_LEVEL0, "Invalid ioctl %x (MEMGETINFO = %x)\n", cmd, MEMGETINFO);
 453                 ret = -ENOTTY;
 454         }
 455
 456         return ret;
 457 } /* memory_ioctl */
 458
 459 static struct file_operations mtd_fops = {
 460         .owner          = THIS_MODULE,
 461         .llseek         = mtd_lseek,
 462         .read           = mtd_read,
 463         .write          = mtd_write,
 464         .ioctl          = mtd_ioctl,
 465         .open           = mtd_open,
 466         .release        = mtd_close,
 467 };
 468
 469
 470 #ifdef CONFIG_DEVFS_FS
 471 /* Notification that a new device has been added. Create the devfs entry for
 472  * it. */
 473
 474 static void mtd_notify_add(struct mtd_info* mtd)
 475 {
 476         if (!mtd)
 477                 return;
 478         devfs_mk_cdev(MKDEV(MTD_CHAR_MAJOR, mtd->index*2),
 479                         S_IFCHR | S_IRUGO | S_IWUGO, "mtd/%d", mtd->index);
 480         devfs_mk_cdev(MKDEV(MTD_CHAR_MAJOR, mtd->index*2+1),
 481                         S_IFCHR | S_IRUGO | S_IWUGO, "mtd/%dro", mtd->index);
 482 }
 483
 484 static void mtd_notify_remove(struct mtd_info* mtd)
 485 {
 486         if (!mtd)
 487                 return;
 488         devfs_remove("mtd/%d", mtd->index);
 489         devfs_remove("mtd/%dro", mtd->index);
 490 }
 491 #endif
 492
 493 static int __init init_mtdchar(void)
 494 {
 495         if (register_chrdev(MTD_CHAR_MAJOR, "mtd", &mtd_fops)) {
 496                 printk(KERN_NOTICE "Can't allocate major number %d for Memory Technology Devices.\n",
 497                        MTD_CHAR_MAJOR);
 498                 return -EAGAIN;
 499         }
 500
 501 #ifdef CONFIG_DEVFS_FS
 502         devfs_mk_dir("mtd");
 503
 504         register_mtd_user(&notifier);
 505 #endif
 506         return 0;
 507 }
 508
 509 static void __exit cleanup_mtdchar(void)
 510 {
 511 #ifdef CONFIG_DEVFS_FS
 512         unregister_mtd_user(&notifier);
 513         devfs_remove("mtd");
 514 #endif
 515         unregister_chrdev(MTD_CHAR_MAJOR, "mtd");
 516 }
 517
 518 module_init(init_mtdchar);
 519 module_exit(cleanup_mtdchar);
 520
 521
 522 MODULE_LICENSE("GPL");
 523 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 524 MODULE_DESCRIPTION("Direct character-device access to MTD devices");