xref: /linux/drivers/mtd/mtdchar.c (revision e190bfe56841551b1ad5abb42ebd0c4798cc8c01)
1 /*
2  * Character-device access to raw MTD devices.
3  *
4  */
5 
6 #include <linux/device.h>
7 #include <linux/fs.h>
8 #include <linux/mm.h>
9 #include <linux/err.h>
10 #include <linux/init.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/sched.h>
15 #include <linux/smp_lock.h>
16 #include <linux/backing-dev.h>
17 #include <linux/compat.h>
18 #include <linux/mount.h>
19 
20 #include <linux/mtd/mtd.h>
21 #include <linux/mtd/compatmac.h>
22 
23 #include <asm/uaccess.h>
24 
25 #define MTD_INODE_FS_MAGIC 0x11307854
26 static struct vfsmount *mtd_inode_mnt __read_mostly;
27 
28 /*
29  * Data structure to hold the pointer to the mtd device as well
30  * as mode information ofr various use cases.
31  */
32 struct mtd_file_info {
33 	struct mtd_info *mtd;
34 	struct inode *ino;
35 	enum mtd_file_modes mode;
36 };
37 
38 static loff_t mtd_lseek (struct file *file, loff_t offset, int orig)
39 {
40 	struct mtd_file_info *mfi = file->private_data;
41 	struct mtd_info *mtd = mfi->mtd;
42 
43 	switch (orig) {
44 	case SEEK_SET:
45 		break;
46 	case SEEK_CUR:
47 		offset += file->f_pos;
48 		break;
49 	case SEEK_END:
50 		offset += mtd->size;
51 		break;
52 	default:
53 		return -EINVAL;
54 	}
55 
56 	if (offset >= 0 && offset <= mtd->size)
57 		return file->f_pos = offset;
58 
59 	return -EINVAL;
60 }
61 
62 
63 
64 static int mtd_open(struct inode *inode, struct file *file)
65 {
66 	int minor = iminor(inode);
67 	int devnum = minor >> 1;
68 	int ret = 0;
69 	struct mtd_info *mtd;
70 	struct mtd_file_info *mfi;
71 	struct inode *mtd_ino;
72 
73 	DEBUG(MTD_DEBUG_LEVEL0, "MTD_open\n");
74 
75 	/* You can't open the RO devices RW */
76 	if ((file->f_mode & FMODE_WRITE) && (minor & 1))
77 		return -EACCES;
78 
79 	lock_kernel();
80 	mtd = get_mtd_device(NULL, devnum);
81 
82 	if (IS_ERR(mtd)) {
83 		ret = PTR_ERR(mtd);
84 		goto out;
85 	}
86 
87 	if (mtd->type == MTD_ABSENT) {
88 		put_mtd_device(mtd);
89 		ret = -ENODEV;
90 		goto out;
91 	}
92 
93 	mtd_ino = iget_locked(mtd_inode_mnt->mnt_sb, devnum);
94 	if (!mtd_ino) {
95 		put_mtd_device(mtd);
96 		ret = -ENOMEM;
97 		goto out;
98 	}
99 	if (mtd_ino->i_state & I_NEW) {
100 		mtd_ino->i_private = mtd;
101 		mtd_ino->i_mode = S_IFCHR;
102 		mtd_ino->i_data.backing_dev_info = mtd->backing_dev_info;
103 		unlock_new_inode(mtd_ino);
104 	}
105 	file->f_mapping = mtd_ino->i_mapping;
106 
107 	/* You can't open it RW if it's not a writeable device */
108 	if ((file->f_mode & FMODE_WRITE) && !(mtd->flags & MTD_WRITEABLE)) {
109 		iput(mtd_ino);
110 		put_mtd_device(mtd);
111 		ret = -EACCES;
112 		goto out;
113 	}
114 
115 	mfi = kzalloc(sizeof(*mfi), GFP_KERNEL);
116 	if (!mfi) {
117 		iput(mtd_ino);
118 		put_mtd_device(mtd);
119 		ret = -ENOMEM;
120 		goto out;
121 	}
122 	mfi->ino = mtd_ino;
123 	mfi->mtd = mtd;
124 	file->private_data = mfi;
125 
126 out:
127 	unlock_kernel();
128 	return ret;
129 } /* mtd_open */
130 
131 /*====================================================================*/
132 
133 static int mtd_close(struct inode *inode, struct file *file)
134 {
135 	struct mtd_file_info *mfi = file->private_data;
136 	struct mtd_info *mtd = mfi->mtd;
137 
138 	DEBUG(MTD_DEBUG_LEVEL0, "MTD_close\n");
139 
140 	/* Only sync if opened RW */
141 	if ((file->f_mode & FMODE_WRITE) && mtd->sync)
142 		mtd->sync(mtd);
143 
144 	iput(mfi->ino);
145 
146 	put_mtd_device(mtd);
147 	file->private_data = NULL;
148 	kfree(mfi);
149 
150 	return 0;
151 } /* mtd_close */
152 
153 /* FIXME: This _really_ needs to die. In 2.5, we should lock the
154    userspace buffer down and use it directly with readv/writev.
155 */
156 #define MAX_KMALLOC_SIZE 0x20000
157 
158 static ssize_t mtd_read(struct file *file, char __user *buf, size_t count,loff_t *ppos)
159 {
160 	struct mtd_file_info *mfi = file->private_data;
161 	struct mtd_info *mtd = mfi->mtd;
162 	size_t retlen=0;
163 	size_t total_retlen=0;
164 	int ret=0;
165 	int len;
166 	char *kbuf;
167 
168 	DEBUG(MTD_DEBUG_LEVEL0,"MTD_read\n");
169 
170 	if (*ppos + count > mtd->size)
171 		count = mtd->size - *ppos;
172 
173 	if (!count)
174 		return 0;
175 
176 	/* FIXME: Use kiovec in 2.5 to lock down the user's buffers
177 	   and pass them directly to the MTD functions */
178 
179 	if (count > MAX_KMALLOC_SIZE)
180 		kbuf=kmalloc(MAX_KMALLOC_SIZE, GFP_KERNEL);
181 	else
182 		kbuf=kmalloc(count, GFP_KERNEL);
183 
184 	if (!kbuf)
185 		return -ENOMEM;
186 
187 	while (count) {
188 
189 		if (count > MAX_KMALLOC_SIZE)
190 			len = MAX_KMALLOC_SIZE;
191 		else
192 			len = count;
193 
194 		switch (mfi->mode) {
195 		case MTD_MODE_OTP_FACTORY:
196 			ret = mtd->read_fact_prot_reg(mtd, *ppos, len, &retlen, kbuf);
197 			break;
198 		case MTD_MODE_OTP_USER:
199 			ret = mtd->read_user_prot_reg(mtd, *ppos, len, &retlen, kbuf);
200 			break;
201 		case MTD_MODE_RAW:
202 		{
203 			struct mtd_oob_ops ops;
204 
205 			ops.mode = MTD_OOB_RAW;
206 			ops.datbuf = kbuf;
207 			ops.oobbuf = NULL;
208 			ops.len = len;
209 
210 			ret = mtd->read_oob(mtd, *ppos, &ops);
211 			retlen = ops.retlen;
212 			break;
213 		}
214 		default:
215 			ret = mtd->read(mtd, *ppos, len, &retlen, kbuf);
216 		}
217 		/* Nand returns -EBADMSG on ecc errors, but it returns
218 		 * the data. For our userspace tools it is important
219 		 * to dump areas with ecc errors !
220 		 * For kernel internal usage it also might return -EUCLEAN
221 		 * to signal the caller that a bitflip has occured and has
222 		 * been corrected by the ECC algorithm.
223 		 * Userspace software which accesses NAND this way
224 		 * must be aware of the fact that it deals with NAND
225 		 */
226 		if (!ret || (ret == -EUCLEAN) || (ret == -EBADMSG)) {
227 			*ppos += retlen;
228 			if (copy_to_user(buf, kbuf, retlen)) {
229 				kfree(kbuf);
230 				return -EFAULT;
231 			}
232 			else
233 				total_retlen += retlen;
234 
235 			count -= retlen;
236 			buf += retlen;
237 			if (retlen == 0)
238 				count = 0;
239 		}
240 		else {
241 			kfree(kbuf);
242 			return ret;
243 		}
244 
245 	}
246 
247 	kfree(kbuf);
248 	return total_retlen;
249 } /* mtd_read */
250 
251 static ssize_t mtd_write(struct file *file, const char __user *buf, size_t count,loff_t *ppos)
252 {
253 	struct mtd_file_info *mfi = file->private_data;
254 	struct mtd_info *mtd = mfi->mtd;
255 	char *kbuf;
256 	size_t retlen;
257 	size_t total_retlen=0;
258 	int ret=0;
259 	int len;
260 
261 	DEBUG(MTD_DEBUG_LEVEL0,"MTD_write\n");
262 
263 	if (*ppos == mtd->size)
264 		return -ENOSPC;
265 
266 	if (*ppos + count > mtd->size)
267 		count = mtd->size - *ppos;
268 
269 	if (!count)
270 		return 0;
271 
272 	if (count > MAX_KMALLOC_SIZE)
273 		kbuf=kmalloc(MAX_KMALLOC_SIZE, GFP_KERNEL);
274 	else
275 		kbuf=kmalloc(count, GFP_KERNEL);
276 
277 	if (!kbuf)
278 		return -ENOMEM;
279 
280 	while (count) {
281 
282 		if (count > MAX_KMALLOC_SIZE)
283 			len = MAX_KMALLOC_SIZE;
284 		else
285 			len = count;
286 
287 		if (copy_from_user(kbuf, buf, len)) {
288 			kfree(kbuf);
289 			return -EFAULT;
290 		}
291 
292 		switch (mfi->mode) {
293 		case MTD_MODE_OTP_FACTORY:
294 			ret = -EROFS;
295 			break;
296 		case MTD_MODE_OTP_USER:
297 			if (!mtd->write_user_prot_reg) {
298 				ret = -EOPNOTSUPP;
299 				break;
300 			}
301 			ret = mtd->write_user_prot_reg(mtd, *ppos, len, &retlen, kbuf);
302 			break;
303 
304 		case MTD_MODE_RAW:
305 		{
306 			struct mtd_oob_ops ops;
307 
308 			ops.mode = MTD_OOB_RAW;
309 			ops.datbuf = kbuf;
310 			ops.oobbuf = NULL;
311 			ops.len = len;
312 
313 			ret = mtd->write_oob(mtd, *ppos, &ops);
314 			retlen = ops.retlen;
315 			break;
316 		}
317 
318 		default:
319 			ret = (*(mtd->write))(mtd, *ppos, len, &retlen, kbuf);
320 		}
321 		if (!ret) {
322 			*ppos += retlen;
323 			total_retlen += retlen;
324 			count -= retlen;
325 			buf += retlen;
326 		}
327 		else {
328 			kfree(kbuf);
329 			return ret;
330 		}
331 	}
332 
333 	kfree(kbuf);
334 	return total_retlen;
335 } /* mtd_write */
336 
337 /*======================================================================
338 
339     IOCTL calls for getting device parameters.
340 
341 ======================================================================*/
342 static void mtdchar_erase_callback (struct erase_info *instr)
343 {
344 	wake_up((wait_queue_head_t *)instr->priv);
345 }
346 
347 #ifdef CONFIG_HAVE_MTD_OTP
348 static int otp_select_filemode(struct mtd_file_info *mfi, int mode)
349 {
350 	struct mtd_info *mtd = mfi->mtd;
351 	int ret = 0;
352 
353 	switch (mode) {
354 	case MTD_OTP_FACTORY:
355 		if (!mtd->read_fact_prot_reg)
356 			ret = -EOPNOTSUPP;
357 		else
358 			mfi->mode = MTD_MODE_OTP_FACTORY;
359 		break;
360 	case MTD_OTP_USER:
361 		if (!mtd->read_fact_prot_reg)
362 			ret = -EOPNOTSUPP;
363 		else
364 			mfi->mode = MTD_MODE_OTP_USER;
365 		break;
366 	default:
367 		ret = -EINVAL;
368 	case MTD_OTP_OFF:
369 		break;
370 	}
371 	return ret;
372 }
373 #else
374 # define otp_select_filemode(f,m)	-EOPNOTSUPP
375 #endif
376 
377 static int mtd_do_writeoob(struct file *file, struct mtd_info *mtd,
378 	uint64_t start, uint32_t length, void __user *ptr,
379 	uint32_t __user *retp)
380 {
381 	struct mtd_oob_ops ops;
382 	uint32_t retlen;
383 	int ret = 0;
384 
385 	if (!(file->f_mode & FMODE_WRITE))
386 		return -EPERM;
387 
388 	if (length > 4096)
389 		return -EINVAL;
390 
391 	if (!mtd->write_oob)
392 		ret = -EOPNOTSUPP;
393 	else
394 		ret = access_ok(VERIFY_READ, ptr, length) ? 0 : -EFAULT;
395 
396 	if (ret)
397 		return ret;
398 
399 	ops.ooblen = length;
400 	ops.ooboffs = start & (mtd->oobsize - 1);
401 	ops.datbuf = NULL;
402 	ops.mode = MTD_OOB_PLACE;
403 
404 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
405 		return -EINVAL;
406 
407 	ops.oobbuf = memdup_user(ptr, length);
408 	if (IS_ERR(ops.oobbuf))
409 		return PTR_ERR(ops.oobbuf);
410 
411 	start &= ~((uint64_t)mtd->oobsize - 1);
412 	ret = mtd->write_oob(mtd, start, &ops);
413 
414 	if (ops.oobretlen > 0xFFFFFFFFU)
415 		ret = -EOVERFLOW;
416 	retlen = ops.oobretlen;
417 	if (copy_to_user(retp, &retlen, sizeof(length)))
418 		ret = -EFAULT;
419 
420 	kfree(ops.oobbuf);
421 	return ret;
422 }
423 
424 static int mtd_do_readoob(struct mtd_info *mtd, uint64_t start,
425 	uint32_t length, void __user *ptr, uint32_t __user *retp)
426 {
427 	struct mtd_oob_ops ops;
428 	int ret = 0;
429 
430 	if (length > 4096)
431 		return -EINVAL;
432 
433 	if (!mtd->read_oob)
434 		ret = -EOPNOTSUPP;
435 	else
436 		ret = access_ok(VERIFY_WRITE, ptr,
437 				length) ? 0 : -EFAULT;
438 	if (ret)
439 		return ret;
440 
441 	ops.ooblen = length;
442 	ops.ooboffs = start & (mtd->oobsize - 1);
443 	ops.datbuf = NULL;
444 	ops.mode = MTD_OOB_PLACE;
445 
446 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
447 		return -EINVAL;
448 
449 	ops.oobbuf = kmalloc(length, GFP_KERNEL);
450 	if (!ops.oobbuf)
451 		return -ENOMEM;
452 
453 	start &= ~((uint64_t)mtd->oobsize - 1);
454 	ret = mtd->read_oob(mtd, start, &ops);
455 
456 	if (put_user(ops.oobretlen, retp))
457 		ret = -EFAULT;
458 	else if (ops.oobretlen && copy_to_user(ptr, ops.oobbuf,
459 					    ops.oobretlen))
460 		ret = -EFAULT;
461 
462 	kfree(ops.oobbuf);
463 	return ret;
464 }
465 
466 static int mtd_ioctl(struct file *file, u_int cmd, u_long arg)
467 {
468 	struct mtd_file_info *mfi = file->private_data;
469 	struct mtd_info *mtd = mfi->mtd;
470 	void __user *argp = (void __user *)arg;
471 	int ret = 0;
472 	u_long size;
473 	struct mtd_info_user info;
474 
475 	DEBUG(MTD_DEBUG_LEVEL0, "MTD_ioctl\n");
476 
477 	size = (cmd & IOCSIZE_MASK) >> IOCSIZE_SHIFT;
478 	if (cmd & IOC_IN) {
479 		if (!access_ok(VERIFY_READ, argp, size))
480 			return -EFAULT;
481 	}
482 	if (cmd & IOC_OUT) {
483 		if (!access_ok(VERIFY_WRITE, argp, size))
484 			return -EFAULT;
485 	}
486 
487 	switch (cmd) {
488 	case MEMGETREGIONCOUNT:
489 		if (copy_to_user(argp, &(mtd->numeraseregions), sizeof(int)))
490 			return -EFAULT;
491 		break;
492 
493 	case MEMGETREGIONINFO:
494 	{
495 		uint32_t ur_idx;
496 		struct mtd_erase_region_info *kr;
497 		struct region_info_user __user *ur = argp;
498 
499 		if (get_user(ur_idx, &(ur->regionindex)))
500 			return -EFAULT;
501 
502 		kr = &(mtd->eraseregions[ur_idx]);
503 
504 		if (put_user(kr->offset, &(ur->offset))
505 		    || put_user(kr->erasesize, &(ur->erasesize))
506 		    || put_user(kr->numblocks, &(ur->numblocks)))
507 			return -EFAULT;
508 
509 		break;
510 	}
511 
512 	case MEMGETINFO:
513 		info.type	= mtd->type;
514 		info.flags	= mtd->flags;
515 		info.size	= mtd->size;
516 		info.erasesize	= mtd->erasesize;
517 		info.writesize	= mtd->writesize;
518 		info.oobsize	= mtd->oobsize;
519 		/* The below fields are obsolete */
520 		info.ecctype	= -1;
521 		info.eccsize	= 0;
522 		if (copy_to_user(argp, &info, sizeof(struct mtd_info_user)))
523 			return -EFAULT;
524 		break;
525 
526 	case MEMERASE:
527 	case MEMERASE64:
528 	{
529 		struct erase_info *erase;
530 
531 		if(!(file->f_mode & FMODE_WRITE))
532 			return -EPERM;
533 
534 		erase=kzalloc(sizeof(struct erase_info),GFP_KERNEL);
535 		if (!erase)
536 			ret = -ENOMEM;
537 		else {
538 			wait_queue_head_t waitq;
539 			DECLARE_WAITQUEUE(wait, current);
540 
541 			init_waitqueue_head(&waitq);
542 
543 			if (cmd == MEMERASE64) {
544 				struct erase_info_user64 einfo64;
545 
546 				if (copy_from_user(&einfo64, argp,
547 					    sizeof(struct erase_info_user64))) {
548 					kfree(erase);
549 					return -EFAULT;
550 				}
551 				erase->addr = einfo64.start;
552 				erase->len = einfo64.length;
553 			} else {
554 				struct erase_info_user einfo32;
555 
556 				if (copy_from_user(&einfo32, argp,
557 					    sizeof(struct erase_info_user))) {
558 					kfree(erase);
559 					return -EFAULT;
560 				}
561 				erase->addr = einfo32.start;
562 				erase->len = einfo32.length;
563 			}
564 			erase->mtd = mtd;
565 			erase->callback = mtdchar_erase_callback;
566 			erase->priv = (unsigned long)&waitq;
567 
568 			/*
569 			  FIXME: Allow INTERRUPTIBLE. Which means
570 			  not having the wait_queue head on the stack.
571 
572 			  If the wq_head is on the stack, and we
573 			  leave because we got interrupted, then the
574 			  wq_head is no longer there when the
575 			  callback routine tries to wake us up.
576 			*/
577 			ret = mtd->erase(mtd, erase);
578 			if (!ret) {
579 				set_current_state(TASK_UNINTERRUPTIBLE);
580 				add_wait_queue(&waitq, &wait);
581 				if (erase->state != MTD_ERASE_DONE &&
582 				    erase->state != MTD_ERASE_FAILED)
583 					schedule();
584 				remove_wait_queue(&waitq, &wait);
585 				set_current_state(TASK_RUNNING);
586 
587 				ret = (erase->state == MTD_ERASE_FAILED)?-EIO:0;
588 			}
589 			kfree(erase);
590 		}
591 		break;
592 	}
593 
594 	case MEMWRITEOOB:
595 	{
596 		struct mtd_oob_buf buf;
597 		struct mtd_oob_buf __user *buf_user = argp;
598 
599 		/* NOTE: writes return length to buf_user->length */
600 		if (copy_from_user(&buf, argp, sizeof(buf)))
601 			ret = -EFAULT;
602 		else
603 			ret = mtd_do_writeoob(file, mtd, buf.start, buf.length,
604 				buf.ptr, &buf_user->length);
605 		break;
606 	}
607 
608 	case MEMREADOOB:
609 	{
610 		struct mtd_oob_buf buf;
611 		struct mtd_oob_buf __user *buf_user = argp;
612 
613 		/* NOTE: writes return length to buf_user->start */
614 		if (copy_from_user(&buf, argp, sizeof(buf)))
615 			ret = -EFAULT;
616 		else
617 			ret = mtd_do_readoob(mtd, buf.start, buf.length,
618 				buf.ptr, &buf_user->start);
619 		break;
620 	}
621 
622 	case MEMWRITEOOB64:
623 	{
624 		struct mtd_oob_buf64 buf;
625 		struct mtd_oob_buf64 __user *buf_user = argp;
626 
627 		if (copy_from_user(&buf, argp, sizeof(buf)))
628 			ret = -EFAULT;
629 		else
630 			ret = mtd_do_writeoob(file, mtd, buf.start, buf.length,
631 				(void __user *)(uintptr_t)buf.usr_ptr,
632 				&buf_user->length);
633 		break;
634 	}
635 
636 	case MEMREADOOB64:
637 	{
638 		struct mtd_oob_buf64 buf;
639 		struct mtd_oob_buf64 __user *buf_user = argp;
640 
641 		if (copy_from_user(&buf, argp, sizeof(buf)))
642 			ret = -EFAULT;
643 		else
644 			ret = mtd_do_readoob(mtd, buf.start, buf.length,
645 				(void __user *)(uintptr_t)buf.usr_ptr,
646 				&buf_user->length);
647 		break;
648 	}
649 
650 	case MEMLOCK:
651 	{
652 		struct erase_info_user einfo;
653 
654 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
655 			return -EFAULT;
656 
657 		if (!mtd->lock)
658 			ret = -EOPNOTSUPP;
659 		else
660 			ret = mtd->lock(mtd, einfo.start, einfo.length);
661 		break;
662 	}
663 
664 	case MEMUNLOCK:
665 	{
666 		struct erase_info_user einfo;
667 
668 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
669 			return -EFAULT;
670 
671 		if (!mtd->unlock)
672 			ret = -EOPNOTSUPP;
673 		else
674 			ret = mtd->unlock(mtd, einfo.start, einfo.length);
675 		break;
676 	}
677 
678 	/* Legacy interface */
679 	case MEMGETOOBSEL:
680 	{
681 		struct nand_oobinfo oi;
682 
683 		if (!mtd->ecclayout)
684 			return -EOPNOTSUPP;
685 		if (mtd->ecclayout->eccbytes > ARRAY_SIZE(oi.eccpos))
686 			return -EINVAL;
687 
688 		oi.useecc = MTD_NANDECC_AUTOPLACE;
689 		memcpy(&oi.eccpos, mtd->ecclayout->eccpos, sizeof(oi.eccpos));
690 		memcpy(&oi.oobfree, mtd->ecclayout->oobfree,
691 		       sizeof(oi.oobfree));
692 		oi.eccbytes = mtd->ecclayout->eccbytes;
693 
694 		if (copy_to_user(argp, &oi, sizeof(struct nand_oobinfo)))
695 			return -EFAULT;
696 		break;
697 	}
698 
699 	case MEMGETBADBLOCK:
700 	{
701 		loff_t offs;
702 
703 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
704 			return -EFAULT;
705 		if (!mtd->block_isbad)
706 			ret = -EOPNOTSUPP;
707 		else
708 			return mtd->block_isbad(mtd, offs);
709 		break;
710 	}
711 
712 	case MEMSETBADBLOCK:
713 	{
714 		loff_t offs;
715 
716 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
717 			return -EFAULT;
718 		if (!mtd->block_markbad)
719 			ret = -EOPNOTSUPP;
720 		else
721 			return mtd->block_markbad(mtd, offs);
722 		break;
723 	}
724 
725 #ifdef CONFIG_HAVE_MTD_OTP
726 	case OTPSELECT:
727 	{
728 		int mode;
729 		if (copy_from_user(&mode, argp, sizeof(int)))
730 			return -EFAULT;
731 
732 		mfi->mode = MTD_MODE_NORMAL;
733 
734 		ret = otp_select_filemode(mfi, mode);
735 
736 		file->f_pos = 0;
737 		break;
738 	}
739 
740 	case OTPGETREGIONCOUNT:
741 	case OTPGETREGIONINFO:
742 	{
743 		struct otp_info *buf = kmalloc(4096, GFP_KERNEL);
744 		if (!buf)
745 			return -ENOMEM;
746 		ret = -EOPNOTSUPP;
747 		switch (mfi->mode) {
748 		case MTD_MODE_OTP_FACTORY:
749 			if (mtd->get_fact_prot_info)
750 				ret = mtd->get_fact_prot_info(mtd, buf, 4096);
751 			break;
752 		case MTD_MODE_OTP_USER:
753 			if (mtd->get_user_prot_info)
754 				ret = mtd->get_user_prot_info(mtd, buf, 4096);
755 			break;
756 		default:
757 			break;
758 		}
759 		if (ret >= 0) {
760 			if (cmd == OTPGETREGIONCOUNT) {
761 				int nbr = ret / sizeof(struct otp_info);
762 				ret = copy_to_user(argp, &nbr, sizeof(int));
763 			} else
764 				ret = copy_to_user(argp, buf, ret);
765 			if (ret)
766 				ret = -EFAULT;
767 		}
768 		kfree(buf);
769 		break;
770 	}
771 
772 	case OTPLOCK:
773 	{
774 		struct otp_info oinfo;
775 
776 		if (mfi->mode != MTD_MODE_OTP_USER)
777 			return -EINVAL;
778 		if (copy_from_user(&oinfo, argp, sizeof(oinfo)))
779 			return -EFAULT;
780 		if (!mtd->lock_user_prot_reg)
781 			return -EOPNOTSUPP;
782 		ret = mtd->lock_user_prot_reg(mtd, oinfo.start, oinfo.length);
783 		break;
784 	}
785 #endif
786 
787 	case ECCGETLAYOUT:
788 	{
789 		if (!mtd->ecclayout)
790 			return -EOPNOTSUPP;
791 
792 		if (copy_to_user(argp, mtd->ecclayout,
793 				 sizeof(struct nand_ecclayout)))
794 			return -EFAULT;
795 		break;
796 	}
797 
798 	case ECCGETSTATS:
799 	{
800 		if (copy_to_user(argp, &mtd->ecc_stats,
801 				 sizeof(struct mtd_ecc_stats)))
802 			return -EFAULT;
803 		break;
804 	}
805 
806 	case MTDFILEMODE:
807 	{
808 		mfi->mode = 0;
809 
810 		switch(arg) {
811 		case MTD_MODE_OTP_FACTORY:
812 		case MTD_MODE_OTP_USER:
813 			ret = otp_select_filemode(mfi, arg);
814 			break;
815 
816 		case MTD_MODE_RAW:
817 			if (!mtd->read_oob || !mtd->write_oob)
818 				return -EOPNOTSUPP;
819 			mfi->mode = arg;
820 
821 		case MTD_MODE_NORMAL:
822 			break;
823 		default:
824 			ret = -EINVAL;
825 		}
826 		file->f_pos = 0;
827 		break;
828 	}
829 
830 	default:
831 		ret = -ENOTTY;
832 	}
833 
834 	return ret;
835 } /* memory_ioctl */
836 
837 static long mtd_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
838 {
839 	int ret;
840 
841 	lock_kernel();
842 	ret = mtd_ioctl(file, cmd, arg);
843 	unlock_kernel();
844 
845 	return ret;
846 }
847 
848 #ifdef CONFIG_COMPAT
849 
850 struct mtd_oob_buf32 {
851 	u_int32_t start;
852 	u_int32_t length;
853 	compat_caddr_t ptr;	/* unsigned char* */
854 };
855 
856 #define MEMWRITEOOB32		_IOWR('M', 3, struct mtd_oob_buf32)
857 #define MEMREADOOB32		_IOWR('M', 4, struct mtd_oob_buf32)
858 
859 static long mtd_compat_ioctl(struct file *file, unsigned int cmd,
860 	unsigned long arg)
861 {
862 	struct mtd_file_info *mfi = file->private_data;
863 	struct mtd_info *mtd = mfi->mtd;
864 	void __user *argp = compat_ptr(arg);
865 	int ret = 0;
866 
867 	lock_kernel();
868 
869 	switch (cmd) {
870 	case MEMWRITEOOB32:
871 	{
872 		struct mtd_oob_buf32 buf;
873 		struct mtd_oob_buf32 __user *buf_user = argp;
874 
875 		if (copy_from_user(&buf, argp, sizeof(buf)))
876 			ret = -EFAULT;
877 		else
878 			ret = mtd_do_writeoob(file, mtd, buf.start,
879 				buf.length, compat_ptr(buf.ptr),
880 				&buf_user->length);
881 		break;
882 	}
883 
884 	case MEMREADOOB32:
885 	{
886 		struct mtd_oob_buf32 buf;
887 		struct mtd_oob_buf32 __user *buf_user = argp;
888 
889 		/* NOTE: writes return length to buf->start */
890 		if (copy_from_user(&buf, argp, sizeof(buf)))
891 			ret = -EFAULT;
892 		else
893 			ret = mtd_do_readoob(mtd, buf.start,
894 				buf.length, compat_ptr(buf.ptr),
895 				&buf_user->start);
896 		break;
897 	}
898 	default:
899 		ret = mtd_ioctl(file, cmd, (unsigned long)argp);
900 	}
901 
902 	unlock_kernel();
903 
904 	return ret;
905 }
906 
907 #endif /* CONFIG_COMPAT */
908 
909 /*
910  * try to determine where a shared mapping can be made
911  * - only supported for NOMMU at the moment (MMU can't doesn't copy private
912  *   mappings)
913  */
914 #ifndef CONFIG_MMU
915 static unsigned long mtd_get_unmapped_area(struct file *file,
916 					   unsigned long addr,
917 					   unsigned long len,
918 					   unsigned long pgoff,
919 					   unsigned long flags)
920 {
921 	struct mtd_file_info *mfi = file->private_data;
922 	struct mtd_info *mtd = mfi->mtd;
923 
924 	if (mtd->get_unmapped_area) {
925 		unsigned long offset;
926 
927 		if (addr != 0)
928 			return (unsigned long) -EINVAL;
929 
930 		if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT))
931 			return (unsigned long) -EINVAL;
932 
933 		offset = pgoff << PAGE_SHIFT;
934 		if (offset > mtd->size - len)
935 			return (unsigned long) -EINVAL;
936 
937 		return mtd->get_unmapped_area(mtd, len, offset, flags);
938 	}
939 
940 	/* can't map directly */
941 	return (unsigned long) -ENOSYS;
942 }
943 #endif
944 
945 /*
946  * set up a mapping for shared memory segments
947  */
948 static int mtd_mmap(struct file *file, struct vm_area_struct *vma)
949 {
950 #ifdef CONFIG_MMU
951 	struct mtd_file_info *mfi = file->private_data;
952 	struct mtd_info *mtd = mfi->mtd;
953 
954 	if (mtd->type == MTD_RAM || mtd->type == MTD_ROM)
955 		return 0;
956 	return -ENOSYS;
957 #else
958 	return vma->vm_flags & VM_SHARED ? 0 : -ENOSYS;
959 #endif
960 }
961 
962 static const struct file_operations mtd_fops = {
963 	.owner		= THIS_MODULE,
964 	.llseek		= mtd_lseek,
965 	.read		= mtd_read,
966 	.write		= mtd_write,
967 	.unlocked_ioctl	= mtd_unlocked_ioctl,
968 #ifdef CONFIG_COMPAT
969 	.compat_ioctl	= mtd_compat_ioctl,
970 #endif
971 	.open		= mtd_open,
972 	.release	= mtd_close,
973 	.mmap		= mtd_mmap,
974 #ifndef CONFIG_MMU
975 	.get_unmapped_area = mtd_get_unmapped_area,
976 #endif
977 };
978 
979 static int mtd_inodefs_get_sb(struct file_system_type *fs_type, int flags,
980                                const char *dev_name, void *data,
981                                struct vfsmount *mnt)
982 {
983         return get_sb_pseudo(fs_type, "mtd_inode:", NULL, MTD_INODE_FS_MAGIC,
984                              mnt);
985 }
986 
987 static struct file_system_type mtd_inodefs_type = {
988        .name = "mtd_inodefs",
989        .get_sb = mtd_inodefs_get_sb,
990        .kill_sb = kill_anon_super,
991 };
992 
993 static void mtdchar_notify_add(struct mtd_info *mtd)
994 {
995 }
996 
997 static void mtdchar_notify_remove(struct mtd_info *mtd)
998 {
999 	struct inode *mtd_ino = ilookup(mtd_inode_mnt->mnt_sb, mtd->index);
1000 
1001 	if (mtd_ino) {
1002 		/* Destroy the inode if it exists */
1003 		mtd_ino->i_nlink = 0;
1004 		iput(mtd_ino);
1005 	}
1006 }
1007 
1008 static struct mtd_notifier mtdchar_notifier = {
1009 	.add = mtdchar_notify_add,
1010 	.remove = mtdchar_notify_remove,
1011 };
1012 
1013 static int __init init_mtdchar(void)
1014 {
1015 	int ret;
1016 
1017 	ret = __register_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS,
1018 				   "mtd", &mtd_fops);
1019 	if (ret < 0) {
1020 		pr_notice("Can't allocate major number %d for "
1021 				"Memory Technology Devices.\n", MTD_CHAR_MAJOR);
1022 		return ret;
1023 	}
1024 
1025 	ret = register_filesystem(&mtd_inodefs_type);
1026 	if (ret) {
1027 		pr_notice("Can't register mtd_inodefs filesystem: %d\n", ret);
1028 		goto err_unregister_chdev;
1029 	}
1030 
1031 	mtd_inode_mnt = kern_mount(&mtd_inodefs_type);
1032 	if (IS_ERR(mtd_inode_mnt)) {
1033 		ret = PTR_ERR(mtd_inode_mnt);
1034 		pr_notice("Error mounting mtd_inodefs filesystem: %d\n", ret);
1035 		goto err_unregister_filesystem;
1036 	}
1037 	register_mtd_user(&mtdchar_notifier);
1038 
1039 	return ret;
1040 
1041 err_unregister_filesystem:
1042 	unregister_filesystem(&mtd_inodefs_type);
1043 err_unregister_chdev:
1044 	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1045 	return ret;
1046 }
1047 
1048 static void __exit cleanup_mtdchar(void)
1049 {
1050 	unregister_mtd_user(&mtdchar_notifier);
1051 	mntput(mtd_inode_mnt);
1052 	unregister_filesystem(&mtd_inodefs_type);
1053 	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1054 }
1055 
1056 module_init(init_mtdchar);
1057 module_exit(cleanup_mtdchar);
1058 
1059 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);
1060 
1061 MODULE_LICENSE("GPL");
1062 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
1063 MODULE_DESCRIPTION("Direct character-device access to MTD devices");
1064 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);
1065