xref: /openbmc/linux/drivers/mtd/mtdchar.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 /*
2  * $Id: mtdchar.c,v 1.76 2005/11/07 11:14:20 gleixner Exp $
3  *
4  * Character-device access to raw MTD devices.
5  *
6  */
7 
8 #include <linux/device.h>
9 #include <linux/fs.h>
10 #include <linux/err.h>
11 #include <linux/init.h>
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/slab.h>
15 #include <linux/sched.h>
16 
17 #include <linux/mtd/mtd.h>
18 #include <linux/mtd/compatmac.h>
19 
20 #include <asm/uaccess.h>
21 
22 static struct class *mtd_class;
23 
24 static void mtd_notify_add(struct mtd_info* mtd)
25 {
26 	if (!mtd)
27 		return;
28 
29 	class_device_create(mtd_class, NULL, MKDEV(MTD_CHAR_MAJOR, mtd->index*2),
30 			    NULL, "mtd%d", mtd->index);
31 
32 	class_device_create(mtd_class, NULL,
33 			    MKDEV(MTD_CHAR_MAJOR, mtd->index*2+1),
34 			    NULL, "mtd%dro", mtd->index);
35 }
36 
37 static void mtd_notify_remove(struct mtd_info* mtd)
38 {
39 	if (!mtd)
40 		return;
41 
42 	class_device_destroy(mtd_class, MKDEV(MTD_CHAR_MAJOR, mtd->index*2));
43 	class_device_destroy(mtd_class, MKDEV(MTD_CHAR_MAJOR, mtd->index*2+1));
44 }
45 
46 static struct mtd_notifier notifier = {
47 	.add	= mtd_notify_add,
48 	.remove	= mtd_notify_remove,
49 };
50 
51 /*
52  * Data structure to hold the pointer to the mtd device as well
53  * as mode information ofr various use cases.
54  */
55 struct mtd_file_info {
56 	struct mtd_info *mtd;
57 	enum mtd_file_modes mode;
58 };
59 
60 static loff_t mtd_lseek (struct file *file, loff_t offset, int orig)
61 {
62 	struct mtd_file_info *mfi = file->private_data;
63 	struct mtd_info *mtd = mfi->mtd;
64 
65 	switch (orig) {
66 	case SEEK_SET:
67 		break;
68 	case SEEK_CUR:
69 		offset += file->f_pos;
70 		break;
71 	case SEEK_END:
72 		offset += mtd->size;
73 		break;
74 	default:
75 		return -EINVAL;
76 	}
77 
78 	if (offset >= 0 && offset <= mtd->size)
79 		return file->f_pos = offset;
80 
81 	return -EINVAL;
82 }
83 
84 
85 
86 static int mtd_open(struct inode *inode, struct file *file)
87 {
88 	int minor = iminor(inode);
89 	int devnum = minor >> 1;
90 	struct mtd_info *mtd;
91 	struct mtd_file_info *mfi;
92 
93 	DEBUG(MTD_DEBUG_LEVEL0, "MTD_open\n");
94 
95 	if (devnum >= MAX_MTD_DEVICES)
96 		return -ENODEV;
97 
98 	/* You can't open the RO devices RW */
99 	if ((file->f_mode & 2) && (minor & 1))
100 		return -EACCES;
101 
102 	mtd = get_mtd_device(NULL, devnum);
103 
104 	if (IS_ERR(mtd))
105 		return PTR_ERR(mtd);
106 
107 	if (MTD_ABSENT == mtd->type) {
108 		put_mtd_device(mtd);
109 		return -ENODEV;
110 	}
111 
112 	/* You can't open it RW if it's not a writeable device */
113 	if ((file->f_mode & 2) && !(mtd->flags & MTD_WRITEABLE)) {
114 		put_mtd_device(mtd);
115 		return -EACCES;
116 	}
117 
118 	mfi = kzalloc(sizeof(*mfi), GFP_KERNEL);
119 	if (!mfi) {
120 		put_mtd_device(mtd);
121 		return -ENOMEM;
122 	}
123 	mfi->mtd = mtd;
124 	file->private_data = mfi;
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_file_info *mfi = file->private_data;
134 	struct mtd_info *mtd = mfi->mtd;
135 
136 	DEBUG(MTD_DEBUG_LEVEL0, "MTD_close\n");
137 
138 	if (mtd->sync)
139 		mtd->sync(mtd);
140 
141 	put_mtd_device(mtd);
142 	file->private_data = NULL;
143 	kfree(mfi);
144 
145 	return 0;
146 } /* mtd_close */
147 
148 /* FIXME: This _really_ needs to die. In 2.5, we should lock the
149    userspace buffer down and use it directly with readv/writev.
150 */
151 #define MAX_KMALLOC_SIZE 0x20000
152 
153 static ssize_t mtd_read(struct file *file, char __user *buf, size_t count,loff_t *ppos)
154 {
155 	struct mtd_file_info *mfi = file->private_data;
156 	struct mtd_info *mtd = mfi->mtd;
157 	size_t retlen=0;
158 	size_t total_retlen=0;
159 	int ret=0;
160 	int len;
161 	char *kbuf;
162 
163 	DEBUG(MTD_DEBUG_LEVEL0,"MTD_read\n");
164 
165 	if (*ppos + count > mtd->size)
166 		count = mtd->size - *ppos;
167 
168 	if (!count)
169 		return 0;
170 
171 	/* FIXME: Use kiovec in 2.5 to lock down the user's buffers
172 	   and pass them directly to the MTD functions */
173 
174 	if (count > MAX_KMALLOC_SIZE)
175 		kbuf=kmalloc(MAX_KMALLOC_SIZE, GFP_KERNEL);
176 	else
177 		kbuf=kmalloc(count, GFP_KERNEL);
178 
179 	if (!kbuf)
180 		return -ENOMEM;
181 
182 	while (count) {
183 
184 		if (count > MAX_KMALLOC_SIZE)
185 			len = MAX_KMALLOC_SIZE;
186 		else
187 			len = count;
188 
189 		switch (mfi->mode) {
190 		case MTD_MODE_OTP_FACTORY:
191 			ret = mtd->read_fact_prot_reg(mtd, *ppos, len, &retlen, kbuf);
192 			break;
193 		case MTD_MODE_OTP_USER:
194 			ret = mtd->read_user_prot_reg(mtd, *ppos, len, &retlen, kbuf);
195 			break;
196 		case MTD_MODE_RAW:
197 		{
198 			struct mtd_oob_ops ops;
199 
200 			ops.mode = MTD_OOB_RAW;
201 			ops.datbuf = kbuf;
202 			ops.oobbuf = NULL;
203 			ops.len = len;
204 
205 			ret = mtd->read_oob(mtd, *ppos, &ops);
206 			retlen = ops.retlen;
207 			break;
208 		}
209 		default:
210 			ret = mtd->read(mtd, *ppos, len, &retlen, kbuf);
211 		}
212 		/* Nand returns -EBADMSG on ecc errors, but it returns
213 		 * the data. For our userspace tools it is important
214 		 * to dump areas with ecc errors !
215 		 * For kernel internal usage it also might return -EUCLEAN
216 		 * to signal the caller that a bitflip has occured and has
217 		 * been corrected by the ECC algorithm.
218 		 * Userspace software which accesses NAND this way
219 		 * must be aware of the fact that it deals with NAND
220 		 */
221 		if (!ret || (ret == -EUCLEAN) || (ret == -EBADMSG)) {
222 			*ppos += retlen;
223 			if (copy_to_user(buf, kbuf, retlen)) {
224 				kfree(kbuf);
225 				return -EFAULT;
226 			}
227 			else
228 				total_retlen += retlen;
229 
230 			count -= retlen;
231 			buf += retlen;
232 			if (retlen == 0)
233 				count = 0;
234 		}
235 		else {
236 			kfree(kbuf);
237 			return ret;
238 		}
239 
240 	}
241 
242 	kfree(kbuf);
243 	return total_retlen;
244 } /* mtd_read */
245 
246 static ssize_t mtd_write(struct file *file, const char __user *buf, size_t count,loff_t *ppos)
247 {
248 	struct mtd_file_info *mfi = file->private_data;
249 	struct mtd_info *mtd = mfi->mtd;
250 	char *kbuf;
251 	size_t retlen;
252 	size_t total_retlen=0;
253 	int ret=0;
254 	int len;
255 
256 	DEBUG(MTD_DEBUG_LEVEL0,"MTD_write\n");
257 
258 	if (*ppos == mtd->size)
259 		return -ENOSPC;
260 
261 	if (*ppos + count > mtd->size)
262 		count = mtd->size - *ppos;
263 
264 	if (!count)
265 		return 0;
266 
267 	if (count > MAX_KMALLOC_SIZE)
268 		kbuf=kmalloc(MAX_KMALLOC_SIZE, GFP_KERNEL);
269 	else
270 		kbuf=kmalloc(count, GFP_KERNEL);
271 
272 	if (!kbuf)
273 		return -ENOMEM;
274 
275 	while (count) {
276 
277 		if (count > MAX_KMALLOC_SIZE)
278 			len = MAX_KMALLOC_SIZE;
279 		else
280 			len = count;
281 
282 		if (copy_from_user(kbuf, buf, len)) {
283 			kfree(kbuf);
284 			return -EFAULT;
285 		}
286 
287 		switch (mfi->mode) {
288 		case MTD_MODE_OTP_FACTORY:
289 			ret = -EROFS;
290 			break;
291 		case MTD_MODE_OTP_USER:
292 			if (!mtd->write_user_prot_reg) {
293 				ret = -EOPNOTSUPP;
294 				break;
295 			}
296 			ret = mtd->write_user_prot_reg(mtd, *ppos, len, &retlen, kbuf);
297 			break;
298 
299 		case MTD_MODE_RAW:
300 		{
301 			struct mtd_oob_ops ops;
302 
303 			ops.mode = MTD_OOB_RAW;
304 			ops.datbuf = kbuf;
305 			ops.oobbuf = NULL;
306 			ops.len = len;
307 
308 			ret = mtd->write_oob(mtd, *ppos, &ops);
309 			retlen = ops.retlen;
310 			break;
311 		}
312 
313 		default:
314 			ret = (*(mtd->write))(mtd, *ppos, len, &retlen, kbuf);
315 		}
316 		if (!ret) {
317 			*ppos += retlen;
318 			total_retlen += retlen;
319 			count -= retlen;
320 			buf += retlen;
321 		}
322 		else {
323 			kfree(kbuf);
324 			return ret;
325 		}
326 	}
327 
328 	kfree(kbuf);
329 	return total_retlen;
330 } /* mtd_write */
331 
332 /*======================================================================
333 
334     IOCTL calls for getting device parameters.
335 
336 ======================================================================*/
337 static void mtdchar_erase_callback (struct erase_info *instr)
338 {
339 	wake_up((wait_queue_head_t *)instr->priv);
340 }
341 
342 #if defined(CONFIG_MTD_OTP) || defined(CONFIG_MTD_ONENAND_OTP)
343 static int otp_select_filemode(struct mtd_file_info *mfi, int mode)
344 {
345 	struct mtd_info *mtd = mfi->mtd;
346 	int ret = 0;
347 
348 	switch (mode) {
349 	case MTD_OTP_FACTORY:
350 		if (!mtd->read_fact_prot_reg)
351 			ret = -EOPNOTSUPP;
352 		else
353 			mfi->mode = MTD_MODE_OTP_FACTORY;
354 		break;
355 	case MTD_OTP_USER:
356 		if (!mtd->read_fact_prot_reg)
357 			ret = -EOPNOTSUPP;
358 		else
359 			mfi->mode = MTD_MODE_OTP_USER;
360 		break;
361 	default:
362 		ret = -EINVAL;
363 	case MTD_OTP_OFF:
364 		break;
365 	}
366 	return ret;
367 }
368 #else
369 # define otp_select_filemode(f,m)	-EOPNOTSUPP
370 #endif
371 
372 static int mtd_ioctl(struct inode *inode, struct file *file,
373 		     u_int cmd, u_long arg)
374 {
375 	struct mtd_file_info *mfi = file->private_data;
376 	struct mtd_info *mtd = mfi->mtd;
377 	void __user *argp = (void __user *)arg;
378 	int ret = 0;
379 	u_long size;
380 	struct mtd_info_user info;
381 
382 	DEBUG(MTD_DEBUG_LEVEL0, "MTD_ioctl\n");
383 
384 	size = (cmd & IOCSIZE_MASK) >> IOCSIZE_SHIFT;
385 	if (cmd & IOC_IN) {
386 		if (!access_ok(VERIFY_READ, argp, size))
387 			return -EFAULT;
388 	}
389 	if (cmd & IOC_OUT) {
390 		if (!access_ok(VERIFY_WRITE, argp, size))
391 			return -EFAULT;
392 	}
393 
394 	switch (cmd) {
395 	case MEMGETREGIONCOUNT:
396 		if (copy_to_user(argp, &(mtd->numeraseregions), sizeof(int)))
397 			return -EFAULT;
398 		break;
399 
400 	case MEMGETREGIONINFO:
401 	{
402 		struct region_info_user ur;
403 
404 		if (copy_from_user(&ur, argp, sizeof(struct region_info_user)))
405 			return -EFAULT;
406 
407 		if (ur.regionindex >= mtd->numeraseregions)
408 			return -EINVAL;
409 		if (copy_to_user(argp, &(mtd->eraseregions[ur.regionindex]),
410 				sizeof(struct mtd_erase_region_info)))
411 			return -EFAULT;
412 		break;
413 	}
414 
415 	case MEMGETINFO:
416 		info.type	= mtd->type;
417 		info.flags	= mtd->flags;
418 		info.size	= mtd->size;
419 		info.erasesize	= mtd->erasesize;
420 		info.writesize	= mtd->writesize;
421 		info.oobsize	= mtd->oobsize;
422 		/* The below fields are obsolete */
423 		info.ecctype	= -1;
424 		info.eccsize	= 0;
425 		if (copy_to_user(argp, &info, sizeof(struct mtd_info_user)))
426 			return -EFAULT;
427 		break;
428 
429 	case MEMERASE:
430 	{
431 		struct erase_info *erase;
432 
433 		if(!(file->f_mode & 2))
434 			return -EPERM;
435 
436 		erase=kzalloc(sizeof(struct erase_info),GFP_KERNEL);
437 		if (!erase)
438 			ret = -ENOMEM;
439 		else {
440 			wait_queue_head_t waitq;
441 			DECLARE_WAITQUEUE(wait, current);
442 
443 			init_waitqueue_head(&waitq);
444 
445 			if (copy_from_user(&erase->addr, argp,
446 				    sizeof(struct erase_info_user))) {
447 				kfree(erase);
448 				return -EFAULT;
449 			}
450 			erase->mtd = mtd;
451 			erase->callback = mtdchar_erase_callback;
452 			erase->priv = (unsigned long)&waitq;
453 
454 			/*
455 			  FIXME: Allow INTERRUPTIBLE. Which means
456 			  not having the wait_queue head on the stack.
457 
458 			  If the wq_head is on the stack, and we
459 			  leave because we got interrupted, then the
460 			  wq_head is no longer there when the
461 			  callback routine tries to wake us up.
462 			*/
463 			ret = mtd->erase(mtd, erase);
464 			if (!ret) {
465 				set_current_state(TASK_UNINTERRUPTIBLE);
466 				add_wait_queue(&waitq, &wait);
467 				if (erase->state != MTD_ERASE_DONE &&
468 				    erase->state != MTD_ERASE_FAILED)
469 					schedule();
470 				remove_wait_queue(&waitq, &wait);
471 				set_current_state(TASK_RUNNING);
472 
473 				ret = (erase->state == MTD_ERASE_FAILED)?-EIO:0;
474 			}
475 			kfree(erase);
476 		}
477 		break;
478 	}
479 
480 	case MEMWRITEOOB:
481 	{
482 		struct mtd_oob_buf buf;
483 		struct mtd_oob_ops ops;
484 
485 		if(!(file->f_mode & 2))
486 			return -EPERM;
487 
488 		if (copy_from_user(&buf, argp, sizeof(struct mtd_oob_buf)))
489 			return -EFAULT;
490 
491 		if (buf.length > 4096)
492 			return -EINVAL;
493 
494 		if (!mtd->write_oob)
495 			ret = -EOPNOTSUPP;
496 		else
497 			ret = access_ok(VERIFY_READ, buf.ptr,
498 					buf.length) ? 0 : EFAULT;
499 
500 		if (ret)
501 			return ret;
502 
503 		ops.ooblen = buf.length;
504 		ops.ooboffs = buf.start & (mtd->oobsize - 1);
505 		ops.datbuf = NULL;
506 		ops.mode = MTD_OOB_PLACE;
507 
508 		if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
509 			return -EINVAL;
510 
511 		ops.oobbuf = kmalloc(buf.length, GFP_KERNEL);
512 		if (!ops.oobbuf)
513 			return -ENOMEM;
514 
515 		if (copy_from_user(ops.oobbuf, buf.ptr, buf.length)) {
516 			kfree(ops.oobbuf);
517 			return -EFAULT;
518 		}
519 
520 		buf.start &= ~(mtd->oobsize - 1);
521 		ret = mtd->write_oob(mtd, buf.start, &ops);
522 
523 		if (copy_to_user(argp + sizeof(uint32_t), &ops.oobretlen,
524 				 sizeof(uint32_t)))
525 			ret = -EFAULT;
526 
527 		kfree(ops.oobbuf);
528 		break;
529 
530 	}
531 
532 	case MEMREADOOB:
533 	{
534 		struct mtd_oob_buf buf;
535 		struct mtd_oob_ops ops;
536 
537 		if (copy_from_user(&buf, argp, sizeof(struct mtd_oob_buf)))
538 			return -EFAULT;
539 
540 		if (buf.length > 4096)
541 			return -EINVAL;
542 
543 		if (!mtd->read_oob)
544 			ret = -EOPNOTSUPP;
545 		else
546 			ret = access_ok(VERIFY_WRITE, buf.ptr,
547 					buf.length) ? 0 : -EFAULT;
548 		if (ret)
549 			return ret;
550 
551 		ops.ooblen = buf.length;
552 		ops.ooboffs = buf.start & (mtd->oobsize - 1);
553 		ops.datbuf = NULL;
554 		ops.mode = MTD_OOB_PLACE;
555 
556 		if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
557 			return -EINVAL;
558 
559 		ops.oobbuf = kmalloc(buf.length, GFP_KERNEL);
560 		if (!ops.oobbuf)
561 			return -ENOMEM;
562 
563 		buf.start &= ~(mtd->oobsize - 1);
564 		ret = mtd->read_oob(mtd, buf.start, &ops);
565 
566 		if (put_user(ops.oobretlen, (uint32_t __user *)argp))
567 			ret = -EFAULT;
568 		else if (ops.oobretlen && copy_to_user(buf.ptr, ops.oobbuf,
569 						    ops.oobretlen))
570 			ret = -EFAULT;
571 
572 		kfree(ops.oobbuf);
573 		break;
574 	}
575 
576 	case MEMLOCK:
577 	{
578 		struct erase_info_user info;
579 
580 		if (copy_from_user(&info, argp, sizeof(info)))
581 			return -EFAULT;
582 
583 		if (!mtd->lock)
584 			ret = -EOPNOTSUPP;
585 		else
586 			ret = mtd->lock(mtd, info.start, info.length);
587 		break;
588 	}
589 
590 	case MEMUNLOCK:
591 	{
592 		struct erase_info_user info;
593 
594 		if (copy_from_user(&info, argp, sizeof(info)))
595 			return -EFAULT;
596 
597 		if (!mtd->unlock)
598 			ret = -EOPNOTSUPP;
599 		else
600 			ret = mtd->unlock(mtd, info.start, info.length);
601 		break;
602 	}
603 
604 	/* Legacy interface */
605 	case MEMGETOOBSEL:
606 	{
607 		struct nand_oobinfo oi;
608 
609 		if (!mtd->ecclayout)
610 			return -EOPNOTSUPP;
611 		if (mtd->ecclayout->eccbytes > ARRAY_SIZE(oi.eccpos))
612 			return -EINVAL;
613 
614 		oi.useecc = MTD_NANDECC_AUTOPLACE;
615 		memcpy(&oi.eccpos, mtd->ecclayout->eccpos, sizeof(oi.eccpos));
616 		memcpy(&oi.oobfree, mtd->ecclayout->oobfree,
617 		       sizeof(oi.oobfree));
618 		oi.eccbytes = mtd->ecclayout->eccbytes;
619 
620 		if (copy_to_user(argp, &oi, sizeof(struct nand_oobinfo)))
621 			return -EFAULT;
622 		break;
623 	}
624 
625 	case MEMGETBADBLOCK:
626 	{
627 		loff_t offs;
628 
629 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
630 			return -EFAULT;
631 		if (!mtd->block_isbad)
632 			ret = -EOPNOTSUPP;
633 		else
634 			return mtd->block_isbad(mtd, offs);
635 		break;
636 	}
637 
638 	case MEMSETBADBLOCK:
639 	{
640 		loff_t offs;
641 
642 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
643 			return -EFAULT;
644 		if (!mtd->block_markbad)
645 			ret = -EOPNOTSUPP;
646 		else
647 			return mtd->block_markbad(mtd, offs);
648 		break;
649 	}
650 
651 #if defined(CONFIG_MTD_OTP) || defined(CONFIG_MTD_ONENAND_OTP)
652 	case OTPSELECT:
653 	{
654 		int mode;
655 		if (copy_from_user(&mode, argp, sizeof(int)))
656 			return -EFAULT;
657 
658 		mfi->mode = MTD_MODE_NORMAL;
659 
660 		ret = otp_select_filemode(mfi, mode);
661 
662 		file->f_pos = 0;
663 		break;
664 	}
665 
666 	case OTPGETREGIONCOUNT:
667 	case OTPGETREGIONINFO:
668 	{
669 		struct otp_info *buf = kmalloc(4096, GFP_KERNEL);
670 		if (!buf)
671 			return -ENOMEM;
672 		ret = -EOPNOTSUPP;
673 		switch (mfi->mode) {
674 		case MTD_MODE_OTP_FACTORY:
675 			if (mtd->get_fact_prot_info)
676 				ret = mtd->get_fact_prot_info(mtd, buf, 4096);
677 			break;
678 		case MTD_MODE_OTP_USER:
679 			if (mtd->get_user_prot_info)
680 				ret = mtd->get_user_prot_info(mtd, buf, 4096);
681 			break;
682 		default:
683 			break;
684 		}
685 		if (ret >= 0) {
686 			if (cmd == OTPGETREGIONCOUNT) {
687 				int nbr = ret / sizeof(struct otp_info);
688 				ret = copy_to_user(argp, &nbr, sizeof(int));
689 			} else
690 				ret = copy_to_user(argp, buf, ret);
691 			if (ret)
692 				ret = -EFAULT;
693 		}
694 		kfree(buf);
695 		break;
696 	}
697 
698 	case OTPLOCK:
699 	{
700 		struct otp_info info;
701 
702 		if (mfi->mode != MTD_MODE_OTP_USER)
703 			return -EINVAL;
704 		if (copy_from_user(&info, argp, sizeof(info)))
705 			return -EFAULT;
706 		if (!mtd->lock_user_prot_reg)
707 			return -EOPNOTSUPP;
708 		ret = mtd->lock_user_prot_reg(mtd, info.start, info.length);
709 		break;
710 	}
711 #endif
712 
713 	case ECCGETLAYOUT:
714 	{
715 		if (!mtd->ecclayout)
716 			return -EOPNOTSUPP;
717 
718 		if (copy_to_user(argp, mtd->ecclayout,
719 				 sizeof(struct nand_ecclayout)))
720 			return -EFAULT;
721 		break;
722 	}
723 
724 	case ECCGETSTATS:
725 	{
726 		if (copy_to_user(argp, &mtd->ecc_stats,
727 				 sizeof(struct mtd_ecc_stats)))
728 			return -EFAULT;
729 		break;
730 	}
731 
732 	case MTDFILEMODE:
733 	{
734 		mfi->mode = 0;
735 
736 		switch(arg) {
737 		case MTD_MODE_OTP_FACTORY:
738 		case MTD_MODE_OTP_USER:
739 			ret = otp_select_filemode(mfi, arg);
740 			break;
741 
742 		case MTD_MODE_RAW:
743 			if (!mtd->read_oob || !mtd->write_oob)
744 				return -EOPNOTSUPP;
745 			mfi->mode = arg;
746 
747 		case MTD_MODE_NORMAL:
748 			break;
749 		default:
750 			ret = -EINVAL;
751 		}
752 		file->f_pos = 0;
753 		break;
754 	}
755 
756 	default:
757 		ret = -ENOTTY;
758 	}
759 
760 	return ret;
761 } /* memory_ioctl */
762 
763 static const struct file_operations mtd_fops = {
764 	.owner		= THIS_MODULE,
765 	.llseek		= mtd_lseek,
766 	.read		= mtd_read,
767 	.write		= mtd_write,
768 	.ioctl		= mtd_ioctl,
769 	.open		= mtd_open,
770 	.release	= mtd_close,
771 };
772 
773 static int __init init_mtdchar(void)
774 {
775 	if (register_chrdev(MTD_CHAR_MAJOR, "mtd", &mtd_fops)) {
776 		printk(KERN_NOTICE "Can't allocate major number %d for Memory Technology Devices.\n",
777 		       MTD_CHAR_MAJOR);
778 		return -EAGAIN;
779 	}
780 
781 	mtd_class = class_create(THIS_MODULE, "mtd");
782 
783 	if (IS_ERR(mtd_class)) {
784 		printk(KERN_ERR "Error creating mtd class.\n");
785 		unregister_chrdev(MTD_CHAR_MAJOR, "mtd");
786 		return PTR_ERR(mtd_class);
787 	}
788 
789 	register_mtd_user(&notifier);
790 	return 0;
791 }
792 
793 static void __exit cleanup_mtdchar(void)
794 {
795 	unregister_mtd_user(&notifier);
796 	class_destroy(mtd_class);
797 	unregister_chrdev(MTD_CHAR_MAJOR, "mtd");
798 }
799 
800 module_init(init_mtdchar);
801 module_exit(cleanup_mtdchar);
802 
803 
804 MODULE_LICENSE("GPL");
805 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
806 MODULE_DESCRIPTION("Direct character-device access to MTD devices");
807