xref: /linux/drivers/mtd/mtdchar.c (revision 2504075d383fcefd746dac42a0cd1c3bdc006bd1)
1 /*
2  * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17  *
18  */
19 
20 #include <linux/device.h>
21 #include <linux/fs.h>
22 #include <linux/mm.h>
23 #include <linux/err.h>
24 #include <linux/init.h>
25 #include <linux/kernel.h>
26 #include <linux/module.h>
27 #include <linux/slab.h>
28 #include <linux/sched.h>
29 #include <linux/mutex.h>
30 #include <linux/backing-dev.h>
31 #include <linux/compat.h>
32 #include <linux/mount.h>
33 
34 #include <linux/mtd/mtd.h>
35 #include <linux/mtd/map.h>
36 
37 #include <asm/uaccess.h>
38 
39 #define MTD_INODE_FS_MAGIC 0x11307854
40 static DEFINE_MUTEX(mtd_mutex);
41 static struct vfsmount *mtd_inode_mnt __read_mostly;
42 
43 /*
44  * Data structure to hold the pointer to the mtd device as well
45  * as mode information ofr various use cases.
46  */
47 struct mtd_file_info {
48 	struct mtd_info *mtd;
49 	struct inode *ino;
50 	enum mtd_file_modes mode;
51 };
52 
53 static loff_t mtd_lseek (struct file *file, loff_t offset, int orig)
54 {
55 	struct mtd_file_info *mfi = file->private_data;
56 	struct mtd_info *mtd = mfi->mtd;
57 
58 	switch (orig) {
59 	case SEEK_SET:
60 		break;
61 	case SEEK_CUR:
62 		offset += file->f_pos;
63 		break;
64 	case SEEK_END:
65 		offset += mtd->size;
66 		break;
67 	default:
68 		return -EINVAL;
69 	}
70 
71 	if (offset >= 0 && offset <= mtd->size)
72 		return file->f_pos = offset;
73 
74 	return -EINVAL;
75 }
76 
77 
78 
79 static int mtd_open(struct inode *inode, struct file *file)
80 {
81 	int minor = iminor(inode);
82 	int devnum = minor >> 1;
83 	int ret = 0;
84 	struct mtd_info *mtd;
85 	struct mtd_file_info *mfi;
86 	struct inode *mtd_ino;
87 
88 	DEBUG(MTD_DEBUG_LEVEL0, "MTD_open\n");
89 
90 	/* You can't open the RO devices RW */
91 	if ((file->f_mode & FMODE_WRITE) && (minor & 1))
92 		return -EACCES;
93 
94 	mutex_lock(&mtd_mutex);
95 	mtd = get_mtd_device(NULL, devnum);
96 
97 	if (IS_ERR(mtd)) {
98 		ret = PTR_ERR(mtd);
99 		goto out;
100 	}
101 
102 	if (mtd->type == MTD_ABSENT) {
103 		put_mtd_device(mtd);
104 		ret = -ENODEV;
105 		goto out;
106 	}
107 
108 	mtd_ino = iget_locked(mtd_inode_mnt->mnt_sb, devnum);
109 	if (!mtd_ino) {
110 		put_mtd_device(mtd);
111 		ret = -ENOMEM;
112 		goto out;
113 	}
114 	if (mtd_ino->i_state & I_NEW) {
115 		mtd_ino->i_private = mtd;
116 		mtd_ino->i_mode = S_IFCHR;
117 		mtd_ino->i_data.backing_dev_info = mtd->backing_dev_info;
118 		unlock_new_inode(mtd_ino);
119 	}
120 	file->f_mapping = mtd_ino->i_mapping;
121 
122 	/* You can't open it RW if it's not a writeable device */
123 	if ((file->f_mode & FMODE_WRITE) && !(mtd->flags & MTD_WRITEABLE)) {
124 		iput(mtd_ino);
125 		put_mtd_device(mtd);
126 		ret = -EACCES;
127 		goto out;
128 	}
129 
130 	mfi = kzalloc(sizeof(*mfi), GFP_KERNEL);
131 	if (!mfi) {
132 		iput(mtd_ino);
133 		put_mtd_device(mtd);
134 		ret = -ENOMEM;
135 		goto out;
136 	}
137 	mfi->ino = mtd_ino;
138 	mfi->mtd = mtd;
139 	file->private_data = mfi;
140 
141 out:
142 	mutex_unlock(&mtd_mutex);
143 	return ret;
144 } /* mtd_open */
145 
146 /*====================================================================*/
147 
148 static int mtd_close(struct inode *inode, struct file *file)
149 {
150 	struct mtd_file_info *mfi = file->private_data;
151 	struct mtd_info *mtd = mfi->mtd;
152 
153 	DEBUG(MTD_DEBUG_LEVEL0, "MTD_close\n");
154 
155 	/* Only sync if opened RW */
156 	if ((file->f_mode & FMODE_WRITE) && mtd->sync)
157 		mtd->sync(mtd);
158 
159 	iput(mfi->ino);
160 
161 	put_mtd_device(mtd);
162 	file->private_data = NULL;
163 	kfree(mfi);
164 
165 	return 0;
166 } /* mtd_close */
167 
168 /* FIXME: This _really_ needs to die. In 2.5, we should lock the
169    userspace buffer down and use it directly with readv/writev.
170 */
171 #define MAX_KMALLOC_SIZE 0x20000
172 
173 static ssize_t mtd_read(struct file *file, char __user *buf, size_t count,loff_t *ppos)
174 {
175 	struct mtd_file_info *mfi = file->private_data;
176 	struct mtd_info *mtd = mfi->mtd;
177 	size_t retlen=0;
178 	size_t total_retlen=0;
179 	int ret=0;
180 	int len;
181 	char *kbuf;
182 
183 	DEBUG(MTD_DEBUG_LEVEL0,"MTD_read\n");
184 
185 	if (*ppos + count > mtd->size)
186 		count = mtd->size - *ppos;
187 
188 	if (!count)
189 		return 0;
190 
191 	/* FIXME: Use kiovec in 2.5 to lock down the user's buffers
192 	   and pass them directly to the MTD functions */
193 
194 	if (count > MAX_KMALLOC_SIZE)
195 		kbuf=kmalloc(MAX_KMALLOC_SIZE, GFP_KERNEL);
196 	else
197 		kbuf=kmalloc(count, GFP_KERNEL);
198 
199 	if (!kbuf)
200 		return -ENOMEM;
201 
202 	while (count) {
203 
204 		if (count > MAX_KMALLOC_SIZE)
205 			len = MAX_KMALLOC_SIZE;
206 		else
207 			len = count;
208 
209 		switch (mfi->mode) {
210 		case MTD_MODE_OTP_FACTORY:
211 			ret = mtd->read_fact_prot_reg(mtd, *ppos, len, &retlen, kbuf);
212 			break;
213 		case MTD_MODE_OTP_USER:
214 			ret = mtd->read_user_prot_reg(mtd, *ppos, len, &retlen, kbuf);
215 			break;
216 		case MTD_MODE_RAW:
217 		{
218 			struct mtd_oob_ops ops;
219 
220 			ops.mode = MTD_OOB_RAW;
221 			ops.datbuf = kbuf;
222 			ops.oobbuf = NULL;
223 			ops.len = len;
224 
225 			ret = mtd->read_oob(mtd, *ppos, &ops);
226 			retlen = ops.retlen;
227 			break;
228 		}
229 		default:
230 			ret = mtd->read(mtd, *ppos, len, &retlen, kbuf);
231 		}
232 		/* Nand returns -EBADMSG on ecc errors, but it returns
233 		 * the data. For our userspace tools it is important
234 		 * to dump areas with ecc errors !
235 		 * For kernel internal usage it also might return -EUCLEAN
236 		 * to signal the caller that a bitflip has occured and has
237 		 * been corrected by the ECC algorithm.
238 		 * Userspace software which accesses NAND this way
239 		 * must be aware of the fact that it deals with NAND
240 		 */
241 		if (!ret || (ret == -EUCLEAN) || (ret == -EBADMSG)) {
242 			*ppos += retlen;
243 			if (copy_to_user(buf, kbuf, retlen)) {
244 				kfree(kbuf);
245 				return -EFAULT;
246 			}
247 			else
248 				total_retlen += retlen;
249 
250 			count -= retlen;
251 			buf += retlen;
252 			if (retlen == 0)
253 				count = 0;
254 		}
255 		else {
256 			kfree(kbuf);
257 			return ret;
258 		}
259 
260 	}
261 
262 	kfree(kbuf);
263 	return total_retlen;
264 } /* mtd_read */
265 
266 static ssize_t mtd_write(struct file *file, const char __user *buf, size_t count,loff_t *ppos)
267 {
268 	struct mtd_file_info *mfi = file->private_data;
269 	struct mtd_info *mtd = mfi->mtd;
270 	char *kbuf;
271 	size_t retlen;
272 	size_t total_retlen=0;
273 	int ret=0;
274 	int len;
275 
276 	DEBUG(MTD_DEBUG_LEVEL0,"MTD_write\n");
277 
278 	if (*ppos == mtd->size)
279 		return -ENOSPC;
280 
281 	if (*ppos + count > mtd->size)
282 		count = mtd->size - *ppos;
283 
284 	if (!count)
285 		return 0;
286 
287 	if (count > MAX_KMALLOC_SIZE)
288 		kbuf=kmalloc(MAX_KMALLOC_SIZE, GFP_KERNEL);
289 	else
290 		kbuf=kmalloc(count, GFP_KERNEL);
291 
292 	if (!kbuf)
293 		return -ENOMEM;
294 
295 	while (count) {
296 
297 		if (count > MAX_KMALLOC_SIZE)
298 			len = MAX_KMALLOC_SIZE;
299 		else
300 			len = count;
301 
302 		if (copy_from_user(kbuf, buf, len)) {
303 			kfree(kbuf);
304 			return -EFAULT;
305 		}
306 
307 		switch (mfi->mode) {
308 		case MTD_MODE_OTP_FACTORY:
309 			ret = -EROFS;
310 			break;
311 		case MTD_MODE_OTP_USER:
312 			if (!mtd->write_user_prot_reg) {
313 				ret = -EOPNOTSUPP;
314 				break;
315 			}
316 			ret = mtd->write_user_prot_reg(mtd, *ppos, len, &retlen, kbuf);
317 			break;
318 
319 		case MTD_MODE_RAW:
320 		{
321 			struct mtd_oob_ops ops;
322 
323 			ops.mode = MTD_OOB_RAW;
324 			ops.datbuf = kbuf;
325 			ops.oobbuf = NULL;
326 			ops.len = len;
327 
328 			ret = mtd->write_oob(mtd, *ppos, &ops);
329 			retlen = ops.retlen;
330 			break;
331 		}
332 
333 		default:
334 			ret = (*(mtd->write))(mtd, *ppos, len, &retlen, kbuf);
335 		}
336 		if (!ret) {
337 			*ppos += retlen;
338 			total_retlen += retlen;
339 			count -= retlen;
340 			buf += retlen;
341 		}
342 		else {
343 			kfree(kbuf);
344 			return ret;
345 		}
346 	}
347 
348 	kfree(kbuf);
349 	return total_retlen;
350 } /* mtd_write */
351 
352 /*======================================================================
353 
354     IOCTL calls for getting device parameters.
355 
356 ======================================================================*/
357 static void mtdchar_erase_callback (struct erase_info *instr)
358 {
359 	wake_up((wait_queue_head_t *)instr->priv);
360 }
361 
362 #ifdef CONFIG_HAVE_MTD_OTP
363 static int otp_select_filemode(struct mtd_file_info *mfi, int mode)
364 {
365 	struct mtd_info *mtd = mfi->mtd;
366 	int ret = 0;
367 
368 	switch (mode) {
369 	case MTD_OTP_FACTORY:
370 		if (!mtd->read_fact_prot_reg)
371 			ret = -EOPNOTSUPP;
372 		else
373 			mfi->mode = MTD_MODE_OTP_FACTORY;
374 		break;
375 	case MTD_OTP_USER:
376 		if (!mtd->read_fact_prot_reg)
377 			ret = -EOPNOTSUPP;
378 		else
379 			mfi->mode = MTD_MODE_OTP_USER;
380 		break;
381 	default:
382 		ret = -EINVAL;
383 	case MTD_OTP_OFF:
384 		break;
385 	}
386 	return ret;
387 }
388 #else
389 # define otp_select_filemode(f,m)	-EOPNOTSUPP
390 #endif
391 
392 static int mtd_do_writeoob(struct file *file, struct mtd_info *mtd,
393 	uint64_t start, uint32_t length, void __user *ptr,
394 	uint32_t __user *retp)
395 {
396 	struct mtd_oob_ops ops;
397 	uint32_t retlen;
398 	int ret = 0;
399 
400 	if (!(file->f_mode & FMODE_WRITE))
401 		return -EPERM;
402 
403 	if (length > 4096)
404 		return -EINVAL;
405 
406 	if (!mtd->write_oob)
407 		ret = -EOPNOTSUPP;
408 	else
409 		ret = access_ok(VERIFY_READ, ptr, length) ? 0 : -EFAULT;
410 
411 	if (ret)
412 		return ret;
413 
414 	ops.ooblen = length;
415 	ops.ooboffs = start & (mtd->oobsize - 1);
416 	ops.datbuf = NULL;
417 	ops.mode = MTD_OOB_PLACE;
418 
419 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
420 		return -EINVAL;
421 
422 	ops.oobbuf = memdup_user(ptr, length);
423 	if (IS_ERR(ops.oobbuf))
424 		return PTR_ERR(ops.oobbuf);
425 
426 	start &= ~((uint64_t)mtd->oobsize - 1);
427 	ret = mtd->write_oob(mtd, start, &ops);
428 
429 	if (ops.oobretlen > 0xFFFFFFFFU)
430 		ret = -EOVERFLOW;
431 	retlen = ops.oobretlen;
432 	if (copy_to_user(retp, &retlen, sizeof(length)))
433 		ret = -EFAULT;
434 
435 	kfree(ops.oobbuf);
436 	return ret;
437 }
438 
439 static int mtd_do_readoob(struct mtd_info *mtd, uint64_t start,
440 	uint32_t length, void __user *ptr, uint32_t __user *retp)
441 {
442 	struct mtd_oob_ops ops;
443 	int ret = 0;
444 
445 	if (length > 4096)
446 		return -EINVAL;
447 
448 	if (!mtd->read_oob)
449 		ret = -EOPNOTSUPP;
450 	else
451 		ret = access_ok(VERIFY_WRITE, ptr,
452 				length) ? 0 : -EFAULT;
453 	if (ret)
454 		return ret;
455 
456 	ops.ooblen = length;
457 	ops.ooboffs = start & (mtd->oobsize - 1);
458 	ops.datbuf = NULL;
459 	ops.mode = MTD_OOB_PLACE;
460 
461 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
462 		return -EINVAL;
463 
464 	ops.oobbuf = kmalloc(length, GFP_KERNEL);
465 	if (!ops.oobbuf)
466 		return -ENOMEM;
467 
468 	start &= ~((uint64_t)mtd->oobsize - 1);
469 	ret = mtd->read_oob(mtd, start, &ops);
470 
471 	if (put_user(ops.oobretlen, retp))
472 		ret = -EFAULT;
473 	else if (ops.oobretlen && copy_to_user(ptr, ops.oobbuf,
474 					    ops.oobretlen))
475 		ret = -EFAULT;
476 
477 	kfree(ops.oobbuf);
478 	return ret;
479 }
480 
481 static int mtd_ioctl(struct file *file, u_int cmd, u_long arg)
482 {
483 	struct mtd_file_info *mfi = file->private_data;
484 	struct mtd_info *mtd = mfi->mtd;
485 	void __user *argp = (void __user *)arg;
486 	int ret = 0;
487 	u_long size;
488 	struct mtd_info_user info;
489 
490 	DEBUG(MTD_DEBUG_LEVEL0, "MTD_ioctl\n");
491 
492 	size = (cmd & IOCSIZE_MASK) >> IOCSIZE_SHIFT;
493 	if (cmd & IOC_IN) {
494 		if (!access_ok(VERIFY_READ, argp, size))
495 			return -EFAULT;
496 	}
497 	if (cmd & IOC_OUT) {
498 		if (!access_ok(VERIFY_WRITE, argp, size))
499 			return -EFAULT;
500 	}
501 
502 	switch (cmd) {
503 	case MEMGETREGIONCOUNT:
504 		if (copy_to_user(argp, &(mtd->numeraseregions), sizeof(int)))
505 			return -EFAULT;
506 		break;
507 
508 	case MEMGETREGIONINFO:
509 	{
510 		uint32_t ur_idx;
511 		struct mtd_erase_region_info *kr;
512 		struct region_info_user __user *ur = argp;
513 
514 		if (get_user(ur_idx, &(ur->regionindex)))
515 			return -EFAULT;
516 
517 		kr = &(mtd->eraseregions[ur_idx]);
518 
519 		if (put_user(kr->offset, &(ur->offset))
520 		    || put_user(kr->erasesize, &(ur->erasesize))
521 		    || put_user(kr->numblocks, &(ur->numblocks)))
522 			return -EFAULT;
523 
524 		break;
525 	}
526 
527 	case MEMGETINFO:
528 		info.type	= mtd->type;
529 		info.flags	= mtd->flags;
530 		info.size	= mtd->size;
531 		info.erasesize	= mtd->erasesize;
532 		info.writesize	= mtd->writesize;
533 		info.oobsize	= mtd->oobsize;
534 		/* The below fields are obsolete */
535 		info.ecctype	= -1;
536 		info.eccsize	= 0;
537 		if (copy_to_user(argp, &info, sizeof(struct mtd_info_user)))
538 			return -EFAULT;
539 		break;
540 
541 	case MEMERASE:
542 	case MEMERASE64:
543 	{
544 		struct erase_info *erase;
545 
546 		if(!(file->f_mode & FMODE_WRITE))
547 			return -EPERM;
548 
549 		erase=kzalloc(sizeof(struct erase_info),GFP_KERNEL);
550 		if (!erase)
551 			ret = -ENOMEM;
552 		else {
553 			wait_queue_head_t waitq;
554 			DECLARE_WAITQUEUE(wait, current);
555 
556 			init_waitqueue_head(&waitq);
557 
558 			if (cmd == MEMERASE64) {
559 				struct erase_info_user64 einfo64;
560 
561 				if (copy_from_user(&einfo64, argp,
562 					    sizeof(struct erase_info_user64))) {
563 					kfree(erase);
564 					return -EFAULT;
565 				}
566 				erase->addr = einfo64.start;
567 				erase->len = einfo64.length;
568 			} else {
569 				struct erase_info_user einfo32;
570 
571 				if (copy_from_user(&einfo32, argp,
572 					    sizeof(struct erase_info_user))) {
573 					kfree(erase);
574 					return -EFAULT;
575 				}
576 				erase->addr = einfo32.start;
577 				erase->len = einfo32.length;
578 			}
579 			erase->mtd = mtd;
580 			erase->callback = mtdchar_erase_callback;
581 			erase->priv = (unsigned long)&waitq;
582 
583 			/*
584 			  FIXME: Allow INTERRUPTIBLE. Which means
585 			  not having the wait_queue head on the stack.
586 
587 			  If the wq_head is on the stack, and we
588 			  leave because we got interrupted, then the
589 			  wq_head is no longer there when the
590 			  callback routine tries to wake us up.
591 			*/
592 			ret = mtd->erase(mtd, erase);
593 			if (!ret) {
594 				set_current_state(TASK_UNINTERRUPTIBLE);
595 				add_wait_queue(&waitq, &wait);
596 				if (erase->state != MTD_ERASE_DONE &&
597 				    erase->state != MTD_ERASE_FAILED)
598 					schedule();
599 				remove_wait_queue(&waitq, &wait);
600 				set_current_state(TASK_RUNNING);
601 
602 				ret = (erase->state == MTD_ERASE_FAILED)?-EIO:0;
603 			}
604 			kfree(erase);
605 		}
606 		break;
607 	}
608 
609 	case MEMWRITEOOB:
610 	{
611 		struct mtd_oob_buf buf;
612 		struct mtd_oob_buf __user *buf_user = argp;
613 
614 		/* NOTE: writes return length to buf_user->length */
615 		if (copy_from_user(&buf, argp, sizeof(buf)))
616 			ret = -EFAULT;
617 		else
618 			ret = mtd_do_writeoob(file, mtd, buf.start, buf.length,
619 				buf.ptr, &buf_user->length);
620 		break;
621 	}
622 
623 	case MEMREADOOB:
624 	{
625 		struct mtd_oob_buf buf;
626 		struct mtd_oob_buf __user *buf_user = argp;
627 
628 		/* NOTE: writes return length to buf_user->start */
629 		if (copy_from_user(&buf, argp, sizeof(buf)))
630 			ret = -EFAULT;
631 		else
632 			ret = mtd_do_readoob(mtd, buf.start, buf.length,
633 				buf.ptr, &buf_user->start);
634 		break;
635 	}
636 
637 	case MEMWRITEOOB64:
638 	{
639 		struct mtd_oob_buf64 buf;
640 		struct mtd_oob_buf64 __user *buf_user = argp;
641 
642 		if (copy_from_user(&buf, argp, sizeof(buf)))
643 			ret = -EFAULT;
644 		else
645 			ret = mtd_do_writeoob(file, mtd, buf.start, buf.length,
646 				(void __user *)(uintptr_t)buf.usr_ptr,
647 				&buf_user->length);
648 		break;
649 	}
650 
651 	case MEMREADOOB64:
652 	{
653 		struct mtd_oob_buf64 buf;
654 		struct mtd_oob_buf64 __user *buf_user = argp;
655 
656 		if (copy_from_user(&buf, argp, sizeof(buf)))
657 			ret = -EFAULT;
658 		else
659 			ret = mtd_do_readoob(mtd, buf.start, buf.length,
660 				(void __user *)(uintptr_t)buf.usr_ptr,
661 				&buf_user->length);
662 		break;
663 	}
664 
665 	case MEMLOCK:
666 	{
667 		struct erase_info_user einfo;
668 
669 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
670 			return -EFAULT;
671 
672 		if (!mtd->lock)
673 			ret = -EOPNOTSUPP;
674 		else
675 			ret = mtd->lock(mtd, einfo.start, einfo.length);
676 		break;
677 	}
678 
679 	case MEMUNLOCK:
680 	{
681 		struct erase_info_user einfo;
682 
683 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
684 			return -EFAULT;
685 
686 		if (!mtd->unlock)
687 			ret = -EOPNOTSUPP;
688 		else
689 			ret = mtd->unlock(mtd, einfo.start, einfo.length);
690 		break;
691 	}
692 
693 	case MEMISLOCKED:
694 	{
695 		struct erase_info_user einfo;
696 
697 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
698 			return -EFAULT;
699 
700 		if (!mtd->is_locked)
701 			ret = -EOPNOTSUPP;
702 		else
703 			ret = mtd->is_locked(mtd, einfo.start, einfo.length);
704 		break;
705 	}
706 
707 	/* Legacy interface */
708 	case MEMGETOOBSEL:
709 	{
710 		struct nand_oobinfo oi;
711 
712 		if (!mtd->ecclayout)
713 			return -EOPNOTSUPP;
714 		if (mtd->ecclayout->eccbytes > ARRAY_SIZE(oi.eccpos))
715 			return -EINVAL;
716 
717 		oi.useecc = MTD_NANDECC_AUTOPLACE;
718 		memcpy(&oi.eccpos, mtd->ecclayout->eccpos, sizeof(oi.eccpos));
719 		memcpy(&oi.oobfree, mtd->ecclayout->oobfree,
720 		       sizeof(oi.oobfree));
721 		oi.eccbytes = mtd->ecclayout->eccbytes;
722 
723 		if (copy_to_user(argp, &oi, sizeof(struct nand_oobinfo)))
724 			return -EFAULT;
725 		break;
726 	}
727 
728 	case MEMGETBADBLOCK:
729 	{
730 		loff_t offs;
731 
732 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
733 			return -EFAULT;
734 		if (!mtd->block_isbad)
735 			ret = -EOPNOTSUPP;
736 		else
737 			return mtd->block_isbad(mtd, offs);
738 		break;
739 	}
740 
741 	case MEMSETBADBLOCK:
742 	{
743 		loff_t offs;
744 
745 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
746 			return -EFAULT;
747 		if (!mtd->block_markbad)
748 			ret = -EOPNOTSUPP;
749 		else
750 			return mtd->block_markbad(mtd, offs);
751 		break;
752 	}
753 
754 #ifdef CONFIG_HAVE_MTD_OTP
755 	case OTPSELECT:
756 	{
757 		int mode;
758 		if (copy_from_user(&mode, argp, sizeof(int)))
759 			return -EFAULT;
760 
761 		mfi->mode = MTD_MODE_NORMAL;
762 
763 		ret = otp_select_filemode(mfi, mode);
764 
765 		file->f_pos = 0;
766 		break;
767 	}
768 
769 	case OTPGETREGIONCOUNT:
770 	case OTPGETREGIONINFO:
771 	{
772 		struct otp_info *buf = kmalloc(4096, GFP_KERNEL);
773 		if (!buf)
774 			return -ENOMEM;
775 		ret = -EOPNOTSUPP;
776 		switch (mfi->mode) {
777 		case MTD_MODE_OTP_FACTORY:
778 			if (mtd->get_fact_prot_info)
779 				ret = mtd->get_fact_prot_info(mtd, buf, 4096);
780 			break;
781 		case MTD_MODE_OTP_USER:
782 			if (mtd->get_user_prot_info)
783 				ret = mtd->get_user_prot_info(mtd, buf, 4096);
784 			break;
785 		default:
786 			break;
787 		}
788 		if (ret >= 0) {
789 			if (cmd == OTPGETREGIONCOUNT) {
790 				int nbr = ret / sizeof(struct otp_info);
791 				ret = copy_to_user(argp, &nbr, sizeof(int));
792 			} else
793 				ret = copy_to_user(argp, buf, ret);
794 			if (ret)
795 				ret = -EFAULT;
796 		}
797 		kfree(buf);
798 		break;
799 	}
800 
801 	case OTPLOCK:
802 	{
803 		struct otp_info oinfo;
804 
805 		if (mfi->mode != MTD_MODE_OTP_USER)
806 			return -EINVAL;
807 		if (copy_from_user(&oinfo, argp, sizeof(oinfo)))
808 			return -EFAULT;
809 		if (!mtd->lock_user_prot_reg)
810 			return -EOPNOTSUPP;
811 		ret = mtd->lock_user_prot_reg(mtd, oinfo.start, oinfo.length);
812 		break;
813 	}
814 #endif
815 
816 	case ECCGETLAYOUT:
817 	{
818 		if (!mtd->ecclayout)
819 			return -EOPNOTSUPP;
820 
821 		if (copy_to_user(argp, mtd->ecclayout,
822 				 sizeof(struct nand_ecclayout)))
823 			return -EFAULT;
824 		break;
825 	}
826 
827 	case ECCGETSTATS:
828 	{
829 		if (copy_to_user(argp, &mtd->ecc_stats,
830 				 sizeof(struct mtd_ecc_stats)))
831 			return -EFAULT;
832 		break;
833 	}
834 
835 	case MTDFILEMODE:
836 	{
837 		mfi->mode = 0;
838 
839 		switch(arg) {
840 		case MTD_MODE_OTP_FACTORY:
841 		case MTD_MODE_OTP_USER:
842 			ret = otp_select_filemode(mfi, arg);
843 			break;
844 
845 		case MTD_MODE_RAW:
846 			if (!mtd->read_oob || !mtd->write_oob)
847 				return -EOPNOTSUPP;
848 			mfi->mode = arg;
849 
850 		case MTD_MODE_NORMAL:
851 			break;
852 		default:
853 			ret = -EINVAL;
854 		}
855 		file->f_pos = 0;
856 		break;
857 	}
858 
859 	default:
860 		ret = -ENOTTY;
861 	}
862 
863 	return ret;
864 } /* memory_ioctl */
865 
866 static long mtd_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
867 {
868 	int ret;
869 
870 	mutex_lock(&mtd_mutex);
871 	ret = mtd_ioctl(file, cmd, arg);
872 	mutex_unlock(&mtd_mutex);
873 
874 	return ret;
875 }
876 
877 #ifdef CONFIG_COMPAT
878 
879 struct mtd_oob_buf32 {
880 	u_int32_t start;
881 	u_int32_t length;
882 	compat_caddr_t ptr;	/* unsigned char* */
883 };
884 
885 #define MEMWRITEOOB32		_IOWR('M', 3, struct mtd_oob_buf32)
886 #define MEMREADOOB32		_IOWR('M', 4, struct mtd_oob_buf32)
887 
888 static long mtd_compat_ioctl(struct file *file, unsigned int cmd,
889 	unsigned long arg)
890 {
891 	struct mtd_file_info *mfi = file->private_data;
892 	struct mtd_info *mtd = mfi->mtd;
893 	void __user *argp = compat_ptr(arg);
894 	int ret = 0;
895 
896 	mutex_lock(&mtd_mutex);
897 
898 	switch (cmd) {
899 	case MEMWRITEOOB32:
900 	{
901 		struct mtd_oob_buf32 buf;
902 		struct mtd_oob_buf32 __user *buf_user = argp;
903 
904 		if (copy_from_user(&buf, argp, sizeof(buf)))
905 			ret = -EFAULT;
906 		else
907 			ret = mtd_do_writeoob(file, mtd, buf.start,
908 				buf.length, compat_ptr(buf.ptr),
909 				&buf_user->length);
910 		break;
911 	}
912 
913 	case MEMREADOOB32:
914 	{
915 		struct mtd_oob_buf32 buf;
916 		struct mtd_oob_buf32 __user *buf_user = argp;
917 
918 		/* NOTE: writes return length to buf->start */
919 		if (copy_from_user(&buf, argp, sizeof(buf)))
920 			ret = -EFAULT;
921 		else
922 			ret = mtd_do_readoob(mtd, buf.start,
923 				buf.length, compat_ptr(buf.ptr),
924 				&buf_user->start);
925 		break;
926 	}
927 	default:
928 		ret = mtd_ioctl(file, cmd, (unsigned long)argp);
929 	}
930 
931 	mutex_unlock(&mtd_mutex);
932 
933 	return ret;
934 }
935 
936 #endif /* CONFIG_COMPAT */
937 
938 /*
939  * try to determine where a shared mapping can be made
940  * - only supported for NOMMU at the moment (MMU can't doesn't copy private
941  *   mappings)
942  */
943 #ifndef CONFIG_MMU
944 static unsigned long mtd_get_unmapped_area(struct file *file,
945 					   unsigned long addr,
946 					   unsigned long len,
947 					   unsigned long pgoff,
948 					   unsigned long flags)
949 {
950 	struct mtd_file_info *mfi = file->private_data;
951 	struct mtd_info *mtd = mfi->mtd;
952 
953 	if (mtd->get_unmapped_area) {
954 		unsigned long offset;
955 
956 		if (addr != 0)
957 			return (unsigned long) -EINVAL;
958 
959 		if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT))
960 			return (unsigned long) -EINVAL;
961 
962 		offset = pgoff << PAGE_SHIFT;
963 		if (offset > mtd->size - len)
964 			return (unsigned long) -EINVAL;
965 
966 		return mtd->get_unmapped_area(mtd, len, offset, flags);
967 	}
968 
969 	/* can't map directly */
970 	return (unsigned long) -ENOSYS;
971 }
972 #endif
973 
974 /*
975  * set up a mapping for shared memory segments
976  */
977 static int mtd_mmap(struct file *file, struct vm_area_struct *vma)
978 {
979 #ifdef CONFIG_MMU
980 	struct mtd_file_info *mfi = file->private_data;
981 	struct mtd_info *mtd = mfi->mtd;
982 	struct map_info *map = mtd->priv;
983 	unsigned long start;
984 	unsigned long off;
985 	u32 len;
986 
987 	if (mtd->type == MTD_RAM || mtd->type == MTD_ROM) {
988 		off = vma->vm_pgoff << PAGE_SHIFT;
989 		start = map->phys;
990 		len = PAGE_ALIGN((start & ~PAGE_MASK) + map->size);
991 		start &= PAGE_MASK;
992 		if ((vma->vm_end - vma->vm_start + off) > len)
993 			return -EINVAL;
994 
995 		off += start;
996 		vma->vm_pgoff = off >> PAGE_SHIFT;
997 		vma->vm_flags |= VM_IO | VM_RESERVED;
998 
999 #ifdef pgprot_noncached
1000 		if (file->f_flags & O_DSYNC || off >= __pa(high_memory))
1001 			vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1002 #endif
1003 		if (io_remap_pfn_range(vma, vma->vm_start, off >> PAGE_SHIFT,
1004 				       vma->vm_end - vma->vm_start,
1005 				       vma->vm_page_prot))
1006 			return -EAGAIN;
1007 
1008 		return 0;
1009 	}
1010 	return -ENOSYS;
1011 #else
1012 	return vma->vm_flags & VM_SHARED ? 0 : -ENOSYS;
1013 #endif
1014 }
1015 
1016 static const struct file_operations mtd_fops = {
1017 	.owner		= THIS_MODULE,
1018 	.llseek		= mtd_lseek,
1019 	.read		= mtd_read,
1020 	.write		= mtd_write,
1021 	.unlocked_ioctl	= mtd_unlocked_ioctl,
1022 #ifdef CONFIG_COMPAT
1023 	.compat_ioctl	= mtd_compat_ioctl,
1024 #endif
1025 	.open		= mtd_open,
1026 	.release	= mtd_close,
1027 	.mmap		= mtd_mmap,
1028 #ifndef CONFIG_MMU
1029 	.get_unmapped_area = mtd_get_unmapped_area,
1030 #endif
1031 };
1032 
1033 static int mtd_inodefs_get_sb(struct file_system_type *fs_type, int flags,
1034                                const char *dev_name, void *data,
1035                                struct vfsmount *mnt)
1036 {
1037         return get_sb_pseudo(fs_type, "mtd_inode:", NULL, MTD_INODE_FS_MAGIC,
1038                              mnt);
1039 }
1040 
1041 static struct file_system_type mtd_inodefs_type = {
1042        .name = "mtd_inodefs",
1043        .get_sb = mtd_inodefs_get_sb,
1044        .kill_sb = kill_anon_super,
1045 };
1046 
1047 static void mtdchar_notify_add(struct mtd_info *mtd)
1048 {
1049 }
1050 
1051 static void mtdchar_notify_remove(struct mtd_info *mtd)
1052 {
1053 	struct inode *mtd_ino = ilookup(mtd_inode_mnt->mnt_sb, mtd->index);
1054 
1055 	if (mtd_ino) {
1056 		/* Destroy the inode if it exists */
1057 		mtd_ino->i_nlink = 0;
1058 		iput(mtd_ino);
1059 	}
1060 }
1061 
1062 static struct mtd_notifier mtdchar_notifier = {
1063 	.add = mtdchar_notify_add,
1064 	.remove = mtdchar_notify_remove,
1065 };
1066 
1067 static int __init init_mtdchar(void)
1068 {
1069 	int ret;
1070 
1071 	ret = __register_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS,
1072 				   "mtd", &mtd_fops);
1073 	if (ret < 0) {
1074 		pr_notice("Can't allocate major number %d for "
1075 				"Memory Technology Devices.\n", MTD_CHAR_MAJOR);
1076 		return ret;
1077 	}
1078 
1079 	ret = register_filesystem(&mtd_inodefs_type);
1080 	if (ret) {
1081 		pr_notice("Can't register mtd_inodefs filesystem: %d\n", ret);
1082 		goto err_unregister_chdev;
1083 	}
1084 
1085 	mtd_inode_mnt = kern_mount(&mtd_inodefs_type);
1086 	if (IS_ERR(mtd_inode_mnt)) {
1087 		ret = PTR_ERR(mtd_inode_mnt);
1088 		pr_notice("Error mounting mtd_inodefs filesystem: %d\n", ret);
1089 		goto err_unregister_filesystem;
1090 	}
1091 	register_mtd_user(&mtdchar_notifier);
1092 
1093 	return ret;
1094 
1095 err_unregister_filesystem:
1096 	unregister_filesystem(&mtd_inodefs_type);
1097 err_unregister_chdev:
1098 	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1099 	return ret;
1100 }
1101 
1102 static void __exit cleanup_mtdchar(void)
1103 {
1104 	unregister_mtd_user(&mtdchar_notifier);
1105 	mntput(mtd_inode_mnt);
1106 	unregister_filesystem(&mtd_inodefs_type);
1107 	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1108 }
1109 
1110 module_init(init_mtdchar);
1111 module_exit(cleanup_mtdchar);
1112 
1113 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);
1114 
1115 MODULE_LICENSE("GPL");
1116 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
1117 MODULE_DESCRIPTION("Direct character-device access to MTD devices");
1118 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);
1119