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 __user *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 __user *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         void __user *argp = (void __user *)arg;
 242         int ret = 0;
 243         u_long size;
 244
 245         DEBUG(MTD_DEBUG_LEVEL0, "MTD_ioctl\n");
 246
 247         size = (cmd & IOCSIZE_MASK) >> IOCSIZE_SHIFT;
 248         if (cmd & IOC_IN) {
 249                 ret = verify_area(VERIFY_READ, argp, size);
 250                 if (ret) return ret;
 251         }
 252         if (cmd & IOC_OUT) {
 253                 ret = verify_area(VERIFY_WRITE, argp, size);
 254                 if (ret) return ret;
 255         }
 256
 257         switch (cmd) {
 258         case MEMGETREGIONCOUNT:
 259                 if (copy_to_user(argp, &(mtd->numeraseregions), sizeof(int)))
 260                         return -EFAULT;
 261                 break;
 262
 263         case MEMGETREGIONINFO:
 264         {
 265                 struct region_info_user ur;
 266
 267                 if (copy_from_user(&ur, argp, sizeof(struct region_info_user)))
 268                         return -EFAULT;
 269
 270                 if (ur.regionindex >= mtd->numeraseregions)
 271                         return -EINVAL;
 272                 if (copy_to_user(argp, &(mtd->eraseregions[ur.regionindex]),
 273                                 sizeof(struct mtd_erase_region_info)))
 274                         return -EFAULT;
 275                 break;
 276         }
 277
 278         case MEMGETINFO:
 279                 if (copy_to_user(argp, mtd, sizeof(struct mtd_info_user)))
 280                         return -EFAULT;
 281                 break;
 282
 283         case MEMERASE:
 284         {
 285                 struct erase_info *erase;
 286
 287                 if(!(file->f_mode & 2))
 288                         return -EPERM;
 289
 290                 erase=kmalloc(sizeof(struct erase_info),GFP_KERNEL);
 291                 if (!erase)
 292                         ret = -ENOMEM;
 293                 else {
 294                         wait_queue_head_t waitq;
 295                         DECLARE_WAITQUEUE(wait, current);
 296
 297                         init_waitqueue_head(&waitq);
 298
 299                         memset (erase,0,sizeof(struct erase_info));
 300                         if (copy_from_user(&erase->addr, argp,
 301                                            2 * sizeof(u_long))) {
 302                                 kfree(erase);
 303                                 return -EFAULT;
 304                         }
 305                         erase->mtd = mtd;
 306                         erase->callback = mtd_erase_callback;
 307                         erase->priv = (unsigned long)&waitq;
 308
 309                         /*
 310                           FIXME: Allow INTERRUPTIBLE. Which means
 311                           not having the wait_queue head on the stack.
 312
 313                           If the wq_head is on the stack, and we
 314                           leave because we got interrupted, then the
 315                           wq_head is no longer there when the
 316                           callback routine tries to wake us up.
 317                         */
 318                         ret = mtd->erase(mtd, erase);
 319                         if (!ret) {
 320                                 set_current_state(TASK_UNINTERRUPTIBLE);
 321                                 add_wait_queue(&waitq, &wait);
 322                                 if (erase->state != MTD_ERASE_DONE &&
 323                                     erase->state != MTD_ERASE_FAILED)
 324                                         schedule();
 325                                 remove_wait_queue(&waitq, &wait);
 326                                 set_current_state(TASK_RUNNING);
 327
 328                                 ret = (erase->state == MTD_ERASE_FAILED)?-EIO:0;
 329                         }
 330                         kfree(erase);
 331                 }
 332                 break;
 333         }
 334
 335         case MEMWRITEOOB:
 336         {
 337                 struct mtd_oob_buf buf;
 338                 void *databuf;
 339                 ssize_t retlen;
 340
 341                 if(!(file->f_mode & 2))
 342                         return -EPERM;
 343
 344                 if (copy_from_user(&buf, argp, sizeof(struct mtd_oob_buf)))
 345                         return -EFAULT;
 346
 347                 if (buf.length > 0x4096)
 348                         return -EINVAL;
 349
 350                 if (!mtd->write_oob)
 351                         ret = -EOPNOTSUPP;
 352                 else
 353                         ret = verify_area(VERIFY_READ, buf.ptr, buf.length);
 354
 355                 if (ret)
 356                         return ret;
 357
 358                 databuf = kmalloc(buf.length, GFP_KERNEL);
 359                 if (!databuf)
 360                         return -ENOMEM;
 361
 362                 if (copy_from_user(databuf, buf.ptr, buf.length)) {
 363                         kfree(databuf);
 364                         return -EFAULT;
 365                 }
 366
 367                 ret = (mtd->write_oob)(mtd, buf.start, buf.length, &retlen, databuf);
 368
 369                 if (copy_to_user(argp + sizeof(u_int32_t), &retlen, sizeof(u_int32_t)))
 370                         ret = -EFAULT;
 371
 372                 kfree(databuf);
 373                 break;
 374
 375         }
 376
 377         case MEMREADOOB:
 378         {
 379                 struct mtd_oob_buf buf;
 380                 void *databuf;
 381                 ssize_t retlen;
 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->read_oob)
 390                         ret = -EOPNOTSUPP;
 391                 else
 392                         ret = verify_area(VERIFY_WRITE, buf.ptr, buf.length);
 393
 394                 if (ret)
 395                         return ret;
 396
 397                 databuf = kmalloc(buf.length, GFP_KERNEL);
 398                 if (!databuf)
 399                         return -ENOMEM;
 400
 401                 ret = (mtd->read_oob)(mtd, buf.start, buf.length, &retlen, databuf);
 402
 403                 if (copy_to_user(argp + sizeof(u_int32_t), &retlen, sizeof(u_int32_t)))
 404                         ret = -EFAULT;
 405                 else if (retlen && copy_to_user(buf.ptr, databuf, retlen))
 406                         ret = -EFAULT;
 407
 408                 kfree(databuf);
 409                 break;
 410         }
 411
 412         case MEMLOCK:
 413         {
 414                 unsigned long adrs[2];
 415
 416                 if (copy_from_user(adrs, argp, 2* sizeof(unsigned long)))
 417                         return -EFAULT;
 418
 419                 if (!mtd->lock)
 420                         ret = -EOPNOTSUPP;
 421                 else
 422                         ret = mtd->lock(mtd, adrs[0], adrs[1]);
 423                 break;
 424         }
 425
 426         case MEMUNLOCK:
 427         {
 428                 unsigned long adrs[2];
 429
 430                 if (copy_from_user(adrs, argp, 2* sizeof(unsigned long)))
 431                         return -EFAULT;
 432
 433                 if (!mtd->unlock)
 434                         ret = -EOPNOTSUPP;
 435                 else
 436                         ret = mtd->unlock(mtd, adrs[0], adrs[1]);
 437                 break;
 438         }
 439
 440         case MEMSETOOBSEL:
 441         {
 442                 if (copy_from_user(&mtd->oobinfo, argp, sizeof(struct nand_oobinfo)))
 443                         return -EFAULT;
 444                 break;
 445         }
 446
 447         default:
 448                 DEBUG(MTD_DEBUG_LEVEL0, "Invalid ioctl %x (MEMGETINFO = %x)\n", cmd, MEMGETINFO);
 449                 ret = -ENOTTY;
 450         }
 451
 452         return ret;
 453 } /* memory_ioctl */
 454
 455 static struct file_operations mtd_fops = {
 456         .owner          = THIS_MODULE,
 457         .llseek         = mtd_lseek,
 458         .read           = mtd_read,
 459         .write          = mtd_write,
 460         .ioctl          = mtd_ioctl,
 461         .open           = mtd_open,
 462         .release        = mtd_close,
 463 };
 464
 465
 466 #ifdef CONFIG_DEVFS_FS
 467 /* Notification that a new device has been added. Create the devfs entry for
 468  * it. */
 469
 470 static void mtd_notify_add(struct mtd_info* mtd)
 471 {
 472         if (!mtd)
 473                 return;
 474         devfs_mk_cdev(MKDEV(MTD_CHAR_MAJOR, mtd->index*2),
 475                         S_IFCHR | S_IRUGO | S_IWUGO, "mtd/%d", mtd->index);
 476         devfs_mk_cdev(MKDEV(MTD_CHAR_MAJOR, mtd->index*2+1),
 477                         S_IFCHR | S_IRUGO | S_IWUGO, "mtd/%dro", mtd->index);
 478 }
 479
 480 static void mtd_notify_remove(struct mtd_info* mtd)
 481 {
 482         if (!mtd)
 483                 return;
 484         devfs_remove("mtd/%d", mtd->index);
 485         devfs_remove("mtd/%dro", mtd->index);
 486 }
 487 #endif
 488
 489 static int __init init_mtdchar(void)
 490 {
 491         if (register_chrdev(MTD_CHAR_MAJOR, "mtd", &mtd_fops)) {
 492                 printk(KERN_NOTICE "Can't allocate major number %d for Memory Technology Devices.\n",
 493                        MTD_CHAR_MAJOR);
 494                 return -EAGAIN;
 495         }
 496
 497 #ifdef CONFIG_DEVFS_FS
 498         devfs_mk_dir("mtd");
 499
 500         register_mtd_user(&notifier);
 501 #endif
 502         return 0;
 503 }
 504
 505 static void __exit cleanup_mtdchar(void)
 506 {
 507 #ifdef CONFIG_DEVFS_FS
 508         unregister_mtd_user(&notifier);
 509         devfs_remove("mtd");
 510 #endif
 511         unregister_chrdev(MTD_CHAR_MAJOR, "mtd");
 512 }
 513
 514 module_init(init_mtdchar);
 515 module_exit(cleanup_mtdchar);
 516
 517
 518 MODULE_LICENSE("GPL");
 519 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 520 MODULE_DESCRIPTION("Direct character-device access to MTD devices");