xref: /linux/drivers/mtd/mtdchar.c (revision dac2639f9833e858139d7e07f6ee45fb2191a9f2)
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 #include <linux/blkpg.h>
34 #include <linux/mtd/mtd.h>
35 #include <linux/mtd/partitions.h>
36 #include <linux/mtd/map.h>
37 
38 #include <asm/uaccess.h>
39 
40 #define MTD_INODE_FS_MAGIC 0x11307854
41 static DEFINE_MUTEX(mtd_mutex);
42 static struct vfsmount *mtd_inode_mnt __read_mostly;
43 
44 /*
45  * Data structure to hold the pointer to the mtd device as well
46  * as mode information of various use cases.
47  */
48 struct mtd_file_info {
49 	struct mtd_info *mtd;
50 	struct inode *ino;
51 	enum mtd_file_modes mode;
52 };
53 
54 static loff_t mtdchar_lseek(struct file *file, loff_t offset, int orig)
55 {
56 	struct mtd_file_info *mfi = file->private_data;
57 	struct mtd_info *mtd = mfi->mtd;
58 
59 	switch (orig) {
60 	case SEEK_SET:
61 		break;
62 	case SEEK_CUR:
63 		offset += file->f_pos;
64 		break;
65 	case SEEK_END:
66 		offset += mtd->size;
67 		break;
68 	default:
69 		return -EINVAL;
70 	}
71 
72 	if (offset >= 0 && offset <= mtd->size)
73 		return file->f_pos = offset;
74 
75 	return -EINVAL;
76 }
77 
78 
79 
80 static int mtdchar_open(struct inode *inode, struct file *file)
81 {
82 	int minor = iminor(inode);
83 	int devnum = minor >> 1;
84 	int ret = 0;
85 	struct mtd_info *mtd;
86 	struct mtd_file_info *mfi;
87 	struct inode *mtd_ino;
88 
89 	pr_debug("MTD_open\n");
90 
91 	/* You can't open the RO devices RW */
92 	if ((file->f_mode & FMODE_WRITE) && (minor & 1))
93 		return -EACCES;
94 
95 	mutex_lock(&mtd_mutex);
96 	mtd = get_mtd_device(NULL, devnum);
97 
98 	if (IS_ERR(mtd)) {
99 		ret = PTR_ERR(mtd);
100 		goto out;
101 	}
102 
103 	if (mtd->type == MTD_ABSENT) {
104 		put_mtd_device(mtd);
105 		ret = -ENODEV;
106 		goto out;
107 	}
108 
109 	mtd_ino = iget_locked(mtd_inode_mnt->mnt_sb, devnum);
110 	if (!mtd_ino) {
111 		put_mtd_device(mtd);
112 		ret = -ENOMEM;
113 		goto out;
114 	}
115 	if (mtd_ino->i_state & I_NEW) {
116 		mtd_ino->i_private = mtd;
117 		mtd_ino->i_mode = S_IFCHR;
118 		mtd_ino->i_data.backing_dev_info = mtd->backing_dev_info;
119 		unlock_new_inode(mtd_ino);
120 	}
121 	file->f_mapping = mtd_ino->i_mapping;
122 
123 	/* You can't open it RW if it's not a writeable device */
124 	if ((file->f_mode & FMODE_WRITE) && !(mtd->flags & MTD_WRITEABLE)) {
125 		iput(mtd_ino);
126 		put_mtd_device(mtd);
127 		ret = -EACCES;
128 		goto out;
129 	}
130 
131 	mfi = kzalloc(sizeof(*mfi), GFP_KERNEL);
132 	if (!mfi) {
133 		iput(mtd_ino);
134 		put_mtd_device(mtd);
135 		ret = -ENOMEM;
136 		goto out;
137 	}
138 	mfi->ino = mtd_ino;
139 	mfi->mtd = mtd;
140 	file->private_data = mfi;
141 
142 out:
143 	mutex_unlock(&mtd_mutex);
144 	return ret;
145 } /* mtdchar_open */
146 
147 /*====================================================================*/
148 
149 static int mtdchar_close(struct inode *inode, struct file *file)
150 {
151 	struct mtd_file_info *mfi = file->private_data;
152 	struct mtd_info *mtd = mfi->mtd;
153 
154 	pr_debug("MTD_close\n");
155 
156 	/* Only sync if opened RW */
157 	if ((file->f_mode & FMODE_WRITE) && mtd->sync)
158 		mtd_sync(mtd);
159 
160 	iput(mfi->ino);
161 
162 	put_mtd_device(mtd);
163 	file->private_data = NULL;
164 	kfree(mfi);
165 
166 	return 0;
167 } /* mtdchar_close */
168 
169 /* Back in June 2001, dwmw2 wrote:
170  *
171  *   FIXME: This _really_ needs to die. In 2.5, we should lock the
172  *   userspace buffer down and use it directly with readv/writev.
173  *
174  * The implementation below, using mtd_kmalloc_up_to, mitigates
175  * allocation failures when the system is under low-memory situations
176  * or if memory is highly fragmented at the cost of reducing the
177  * performance of the requested transfer due to a smaller buffer size.
178  *
179  * A more complex but more memory-efficient implementation based on
180  * get_user_pages and iovecs to cover extents of those pages is a
181  * longer-term goal, as intimated by dwmw2 above. However, for the
182  * write case, this requires yet more complex head and tail transfer
183  * handling when those head and tail offsets and sizes are such that
184  * alignment requirements are not met in the NAND subdriver.
185  */
186 
187 static ssize_t mtdchar_read(struct file *file, char __user *buf, size_t count,
188 			loff_t *ppos)
189 {
190 	struct mtd_file_info *mfi = file->private_data;
191 	struct mtd_info *mtd = mfi->mtd;
192 	size_t retlen;
193 	size_t total_retlen=0;
194 	int ret=0;
195 	int len;
196 	size_t size = count;
197 	char *kbuf;
198 
199 	pr_debug("MTD_read\n");
200 
201 	if (*ppos + count > mtd->size)
202 		count = mtd->size - *ppos;
203 
204 	if (!count)
205 		return 0;
206 
207 	kbuf = mtd_kmalloc_up_to(mtd, &size);
208 	if (!kbuf)
209 		return -ENOMEM;
210 
211 	while (count) {
212 		len = min_t(size_t, count, size);
213 
214 		switch (mfi->mode) {
215 		case MTD_FILE_MODE_OTP_FACTORY:
216 			ret = mtd_read_fact_prot_reg(mtd, *ppos, len,
217 						     &retlen, kbuf);
218 			break;
219 		case MTD_FILE_MODE_OTP_USER:
220 			ret = mtd_read_user_prot_reg(mtd, *ppos, len,
221 						     &retlen, kbuf);
222 			break;
223 		case MTD_FILE_MODE_RAW:
224 		{
225 			struct mtd_oob_ops ops;
226 
227 			ops.mode = MTD_OPS_RAW;
228 			ops.datbuf = kbuf;
229 			ops.oobbuf = NULL;
230 			ops.len = len;
231 
232 			ret = mtd_read_oob(mtd, *ppos, &ops);
233 			retlen = ops.retlen;
234 			break;
235 		}
236 		default:
237 			ret = mtd_read(mtd, *ppos, len, &retlen, kbuf);
238 		}
239 		/* Nand returns -EBADMSG on ECC errors, but it returns
240 		 * the data. For our userspace tools it is important
241 		 * to dump areas with ECC errors!
242 		 * For kernel internal usage it also might return -EUCLEAN
243 		 * to signal the caller that a bitflip has occurred and has
244 		 * been corrected by the ECC algorithm.
245 		 * Userspace software which accesses NAND this way
246 		 * must be aware of the fact that it deals with NAND
247 		 */
248 		if (!ret || mtd_is_bitflip_or_eccerr(ret)) {
249 			*ppos += retlen;
250 			if (copy_to_user(buf, kbuf, retlen)) {
251 				kfree(kbuf);
252 				return -EFAULT;
253 			}
254 			else
255 				total_retlen += retlen;
256 
257 			count -= retlen;
258 			buf += retlen;
259 			if (retlen == 0)
260 				count = 0;
261 		}
262 		else {
263 			kfree(kbuf);
264 			return ret;
265 		}
266 
267 	}
268 
269 	kfree(kbuf);
270 	return total_retlen;
271 } /* mtdchar_read */
272 
273 static ssize_t mtdchar_write(struct file *file, const char __user *buf, size_t count,
274 			loff_t *ppos)
275 {
276 	struct mtd_file_info *mfi = file->private_data;
277 	struct mtd_info *mtd = mfi->mtd;
278 	size_t size = count;
279 	char *kbuf;
280 	size_t retlen;
281 	size_t total_retlen=0;
282 	int ret=0;
283 	int len;
284 
285 	pr_debug("MTD_write\n");
286 
287 	if (*ppos == mtd->size)
288 		return -ENOSPC;
289 
290 	if (*ppos + count > mtd->size)
291 		count = mtd->size - *ppos;
292 
293 	if (!count)
294 		return 0;
295 
296 	kbuf = mtd_kmalloc_up_to(mtd, &size);
297 	if (!kbuf)
298 		return -ENOMEM;
299 
300 	while (count) {
301 		len = min_t(size_t, count, size);
302 
303 		if (copy_from_user(kbuf, buf, len)) {
304 			kfree(kbuf);
305 			return -EFAULT;
306 		}
307 
308 		switch (mfi->mode) {
309 		case MTD_FILE_MODE_OTP_FACTORY:
310 			ret = -EROFS;
311 			break;
312 		case MTD_FILE_MODE_OTP_USER:
313 			if (!mtd->write_user_prot_reg) {
314 				ret = -EOPNOTSUPP;
315 				break;
316 			}
317 			ret = mtd_write_user_prot_reg(mtd, *ppos, len,
318 						      &retlen, kbuf);
319 			break;
320 
321 		case MTD_FILE_MODE_RAW:
322 		{
323 			struct mtd_oob_ops ops;
324 
325 			ops.mode = MTD_OPS_RAW;
326 			ops.datbuf = kbuf;
327 			ops.oobbuf = NULL;
328 			ops.ooboffs = 0;
329 			ops.len = len;
330 
331 			ret = mtd_write_oob(mtd, *ppos, &ops);
332 			retlen = ops.retlen;
333 			break;
334 		}
335 
336 		default:
337 			ret = mtd_write(mtd, *ppos, len, &retlen, kbuf);
338 		}
339 		if (!ret) {
340 			*ppos += retlen;
341 			total_retlen += retlen;
342 			count -= retlen;
343 			buf += retlen;
344 		}
345 		else {
346 			kfree(kbuf);
347 			return ret;
348 		}
349 	}
350 
351 	kfree(kbuf);
352 	return total_retlen;
353 } /* mtdchar_write */
354 
355 /*======================================================================
356 
357     IOCTL calls for getting device parameters.
358 
359 ======================================================================*/
360 static void mtdchar_erase_callback (struct erase_info *instr)
361 {
362 	wake_up((wait_queue_head_t *)instr->priv);
363 }
364 
365 #ifdef CONFIG_HAVE_MTD_OTP
366 static int otp_select_filemode(struct mtd_file_info *mfi, int mode)
367 {
368 	struct mtd_info *mtd = mfi->mtd;
369 	int ret = 0;
370 
371 	switch (mode) {
372 	case MTD_OTP_FACTORY:
373 		if (!mtd->read_fact_prot_reg)
374 			ret = -EOPNOTSUPP;
375 		else
376 			mfi->mode = MTD_FILE_MODE_OTP_FACTORY;
377 		break;
378 	case MTD_OTP_USER:
379 		if (!mtd->read_fact_prot_reg)
380 			ret = -EOPNOTSUPP;
381 		else
382 			mfi->mode = MTD_FILE_MODE_OTP_USER;
383 		break;
384 	default:
385 		ret = -EINVAL;
386 	case MTD_OTP_OFF:
387 		break;
388 	}
389 	return ret;
390 }
391 #else
392 # define otp_select_filemode(f,m)	-EOPNOTSUPP
393 #endif
394 
395 static int mtdchar_writeoob(struct file *file, struct mtd_info *mtd,
396 	uint64_t start, uint32_t length, void __user *ptr,
397 	uint32_t __user *retp)
398 {
399 	struct mtd_file_info *mfi = file->private_data;
400 	struct mtd_oob_ops ops;
401 	uint32_t retlen;
402 	int ret = 0;
403 
404 	if (!(file->f_mode & FMODE_WRITE))
405 		return -EPERM;
406 
407 	if (length > 4096)
408 		return -EINVAL;
409 
410 	if (!mtd->write_oob)
411 		ret = -EOPNOTSUPP;
412 	else
413 		ret = access_ok(VERIFY_READ, ptr, length) ? 0 : -EFAULT;
414 
415 	if (ret)
416 		return ret;
417 
418 	ops.ooblen = length;
419 	ops.ooboffs = start & (mtd->writesize - 1);
420 	ops.datbuf = NULL;
421 	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
422 		MTD_OPS_PLACE_OOB;
423 
424 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
425 		return -EINVAL;
426 
427 	ops.oobbuf = memdup_user(ptr, length);
428 	if (IS_ERR(ops.oobbuf))
429 		return PTR_ERR(ops.oobbuf);
430 
431 	start &= ~((uint64_t)mtd->writesize - 1);
432 	ret = mtd_write_oob(mtd, start, &ops);
433 
434 	if (ops.oobretlen > 0xFFFFFFFFU)
435 		ret = -EOVERFLOW;
436 	retlen = ops.oobretlen;
437 	if (copy_to_user(retp, &retlen, sizeof(length)))
438 		ret = -EFAULT;
439 
440 	kfree(ops.oobbuf);
441 	return ret;
442 }
443 
444 static int mtdchar_readoob(struct file *file, struct mtd_info *mtd,
445 	uint64_t start, uint32_t length, void __user *ptr,
446 	uint32_t __user *retp)
447 {
448 	struct mtd_file_info *mfi = file->private_data;
449 	struct mtd_oob_ops ops;
450 	int ret = 0;
451 
452 	if (length > 4096)
453 		return -EINVAL;
454 
455 	if (!access_ok(VERIFY_WRITE, ptr, length))
456 		return -EFAULT;
457 
458 	ops.ooblen = length;
459 	ops.ooboffs = start & (mtd->writesize - 1);
460 	ops.datbuf = NULL;
461 	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
462 		MTD_OPS_PLACE_OOB;
463 
464 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
465 		return -EINVAL;
466 
467 	ops.oobbuf = kmalloc(length, GFP_KERNEL);
468 	if (!ops.oobbuf)
469 		return -ENOMEM;
470 
471 	start &= ~((uint64_t)mtd->writesize - 1);
472 	ret = mtd_read_oob(mtd, start, &ops);
473 
474 	if (put_user(ops.oobretlen, retp))
475 		ret = -EFAULT;
476 	else if (ops.oobretlen && copy_to_user(ptr, ops.oobbuf,
477 					    ops.oobretlen))
478 		ret = -EFAULT;
479 
480 	kfree(ops.oobbuf);
481 
482 	/*
483 	 * NAND returns -EBADMSG on ECC errors, but it returns the OOB
484 	 * data. For our userspace tools it is important to dump areas
485 	 * with ECC errors!
486 	 * For kernel internal usage it also might return -EUCLEAN
487 	 * to signal the caller that a bitflip has occured and has
488 	 * been corrected by the ECC algorithm.
489 	 *
490 	 * Note: currently the standard NAND function, nand_read_oob_std,
491 	 * does not calculate ECC for the OOB area, so do not rely on
492 	 * this behavior unless you have replaced it with your own.
493 	 */
494 	if (mtd_is_bitflip_or_eccerr(ret))
495 		return 0;
496 
497 	return ret;
498 }
499 
500 /*
501  * Copies (and truncates, if necessary) data from the larger struct,
502  * nand_ecclayout, to the smaller, deprecated layout struct,
503  * nand_ecclayout_user. This is necessary only to support the deprecated
504  * API ioctl ECCGETLAYOUT while allowing all new functionality to use
505  * nand_ecclayout flexibly (i.e. the struct may change size in new
506  * releases without requiring major rewrites).
507  */
508 static int shrink_ecclayout(const struct nand_ecclayout *from,
509 		struct nand_ecclayout_user *to)
510 {
511 	int i;
512 
513 	if (!from || !to)
514 		return -EINVAL;
515 
516 	memset(to, 0, sizeof(*to));
517 
518 	to->eccbytes = min((int)from->eccbytes, MTD_MAX_ECCPOS_ENTRIES);
519 	for (i = 0; i < to->eccbytes; i++)
520 		to->eccpos[i] = from->eccpos[i];
521 
522 	for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES; i++) {
523 		if (from->oobfree[i].length == 0 &&
524 				from->oobfree[i].offset == 0)
525 			break;
526 		to->oobavail += from->oobfree[i].length;
527 		to->oobfree[i] = from->oobfree[i];
528 	}
529 
530 	return 0;
531 }
532 
533 static int mtdchar_blkpg_ioctl(struct mtd_info *mtd,
534 			   struct blkpg_ioctl_arg __user *arg)
535 {
536 	struct blkpg_ioctl_arg a;
537 	struct blkpg_partition p;
538 
539 	if (!capable(CAP_SYS_ADMIN))
540 		return -EPERM;
541 
542 	if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
543 		return -EFAULT;
544 
545 	if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
546 		return -EFAULT;
547 
548 	switch (a.op) {
549 	case BLKPG_ADD_PARTITION:
550 
551 		/* Only master mtd device must be used to add partitions */
552 		if (mtd_is_partition(mtd))
553 			return -EINVAL;
554 
555 		return mtd_add_partition(mtd, p.devname, p.start, p.length);
556 
557 	case BLKPG_DEL_PARTITION:
558 
559 		if (p.pno < 0)
560 			return -EINVAL;
561 
562 		return mtd_del_partition(mtd, p.pno);
563 
564 	default:
565 		return -EINVAL;
566 	}
567 }
568 
569 static int mtdchar_write_ioctl(struct mtd_info *mtd,
570 		struct mtd_write_req __user *argp)
571 {
572 	struct mtd_write_req req;
573 	struct mtd_oob_ops ops;
574 	void __user *usr_data, *usr_oob;
575 	int ret;
576 
577 	if (copy_from_user(&req, argp, sizeof(req)) ||
578 			!access_ok(VERIFY_READ, req.usr_data, req.len) ||
579 			!access_ok(VERIFY_READ, req.usr_oob, req.ooblen))
580 		return -EFAULT;
581 	if (!mtd->write_oob)
582 		return -EOPNOTSUPP;
583 
584 	ops.mode = req.mode;
585 	ops.len = (size_t)req.len;
586 	ops.ooblen = (size_t)req.ooblen;
587 	ops.ooboffs = 0;
588 
589 	usr_data = (void __user *)(uintptr_t)req.usr_data;
590 	usr_oob = (void __user *)(uintptr_t)req.usr_oob;
591 
592 	if (req.usr_data) {
593 		ops.datbuf = memdup_user(usr_data, ops.len);
594 		if (IS_ERR(ops.datbuf))
595 			return PTR_ERR(ops.datbuf);
596 	} else {
597 		ops.datbuf = NULL;
598 	}
599 
600 	if (req.usr_oob) {
601 		ops.oobbuf = memdup_user(usr_oob, ops.ooblen);
602 		if (IS_ERR(ops.oobbuf)) {
603 			kfree(ops.datbuf);
604 			return PTR_ERR(ops.oobbuf);
605 		}
606 	} else {
607 		ops.oobbuf = NULL;
608 	}
609 
610 	ret = mtd_write_oob(mtd, (loff_t)req.start, &ops);
611 
612 	kfree(ops.datbuf);
613 	kfree(ops.oobbuf);
614 
615 	return ret;
616 }
617 
618 static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg)
619 {
620 	struct mtd_file_info *mfi = file->private_data;
621 	struct mtd_info *mtd = mfi->mtd;
622 	void __user *argp = (void __user *)arg;
623 	int ret = 0;
624 	u_long size;
625 	struct mtd_info_user info;
626 
627 	pr_debug("MTD_ioctl\n");
628 
629 	size = (cmd & IOCSIZE_MASK) >> IOCSIZE_SHIFT;
630 	if (cmd & IOC_IN) {
631 		if (!access_ok(VERIFY_READ, argp, size))
632 			return -EFAULT;
633 	}
634 	if (cmd & IOC_OUT) {
635 		if (!access_ok(VERIFY_WRITE, argp, size))
636 			return -EFAULT;
637 	}
638 
639 	switch (cmd) {
640 	case MEMGETREGIONCOUNT:
641 		if (copy_to_user(argp, &(mtd->numeraseregions), sizeof(int)))
642 			return -EFAULT;
643 		break;
644 
645 	case MEMGETREGIONINFO:
646 	{
647 		uint32_t ur_idx;
648 		struct mtd_erase_region_info *kr;
649 		struct region_info_user __user *ur = argp;
650 
651 		if (get_user(ur_idx, &(ur->regionindex)))
652 			return -EFAULT;
653 
654 		if (ur_idx >= mtd->numeraseregions)
655 			return -EINVAL;
656 
657 		kr = &(mtd->eraseregions[ur_idx]);
658 
659 		if (put_user(kr->offset, &(ur->offset))
660 		    || put_user(kr->erasesize, &(ur->erasesize))
661 		    || put_user(kr->numblocks, &(ur->numblocks)))
662 			return -EFAULT;
663 
664 		break;
665 	}
666 
667 	case MEMGETINFO:
668 		memset(&info, 0, sizeof(info));
669 		info.type	= mtd->type;
670 		info.flags	= mtd->flags;
671 		info.size	= mtd->size;
672 		info.erasesize	= mtd->erasesize;
673 		info.writesize	= mtd->writesize;
674 		info.oobsize	= mtd->oobsize;
675 		/* The below field is obsolete */
676 		info.padding	= 0;
677 		if (copy_to_user(argp, &info, sizeof(struct mtd_info_user)))
678 			return -EFAULT;
679 		break;
680 
681 	case MEMERASE:
682 	case MEMERASE64:
683 	{
684 		struct erase_info *erase;
685 
686 		if(!(file->f_mode & FMODE_WRITE))
687 			return -EPERM;
688 
689 		erase=kzalloc(sizeof(struct erase_info),GFP_KERNEL);
690 		if (!erase)
691 			ret = -ENOMEM;
692 		else {
693 			wait_queue_head_t waitq;
694 			DECLARE_WAITQUEUE(wait, current);
695 
696 			init_waitqueue_head(&waitq);
697 
698 			if (cmd == MEMERASE64) {
699 				struct erase_info_user64 einfo64;
700 
701 				if (copy_from_user(&einfo64, argp,
702 					    sizeof(struct erase_info_user64))) {
703 					kfree(erase);
704 					return -EFAULT;
705 				}
706 				erase->addr = einfo64.start;
707 				erase->len = einfo64.length;
708 			} else {
709 				struct erase_info_user einfo32;
710 
711 				if (copy_from_user(&einfo32, argp,
712 					    sizeof(struct erase_info_user))) {
713 					kfree(erase);
714 					return -EFAULT;
715 				}
716 				erase->addr = einfo32.start;
717 				erase->len = einfo32.length;
718 			}
719 			erase->mtd = mtd;
720 			erase->callback = mtdchar_erase_callback;
721 			erase->priv = (unsigned long)&waitq;
722 
723 			/*
724 			  FIXME: Allow INTERRUPTIBLE. Which means
725 			  not having the wait_queue head on the stack.
726 
727 			  If the wq_head is on the stack, and we
728 			  leave because we got interrupted, then the
729 			  wq_head is no longer there when the
730 			  callback routine tries to wake us up.
731 			*/
732 			ret = mtd_erase(mtd, erase);
733 			if (!ret) {
734 				set_current_state(TASK_UNINTERRUPTIBLE);
735 				add_wait_queue(&waitq, &wait);
736 				if (erase->state != MTD_ERASE_DONE &&
737 				    erase->state != MTD_ERASE_FAILED)
738 					schedule();
739 				remove_wait_queue(&waitq, &wait);
740 				set_current_state(TASK_RUNNING);
741 
742 				ret = (erase->state == MTD_ERASE_FAILED)?-EIO:0;
743 			}
744 			kfree(erase);
745 		}
746 		break;
747 	}
748 
749 	case MEMWRITEOOB:
750 	{
751 		struct mtd_oob_buf buf;
752 		struct mtd_oob_buf __user *buf_user = argp;
753 
754 		/* NOTE: writes return length to buf_user->length */
755 		if (copy_from_user(&buf, argp, sizeof(buf)))
756 			ret = -EFAULT;
757 		else
758 			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
759 				buf.ptr, &buf_user->length);
760 		break;
761 	}
762 
763 	case MEMREADOOB:
764 	{
765 		struct mtd_oob_buf buf;
766 		struct mtd_oob_buf __user *buf_user = argp;
767 
768 		/* NOTE: writes return length to buf_user->start */
769 		if (copy_from_user(&buf, argp, sizeof(buf)))
770 			ret = -EFAULT;
771 		else
772 			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
773 				buf.ptr, &buf_user->start);
774 		break;
775 	}
776 
777 	case MEMWRITEOOB64:
778 	{
779 		struct mtd_oob_buf64 buf;
780 		struct mtd_oob_buf64 __user *buf_user = argp;
781 
782 		if (copy_from_user(&buf, argp, sizeof(buf)))
783 			ret = -EFAULT;
784 		else
785 			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
786 				(void __user *)(uintptr_t)buf.usr_ptr,
787 				&buf_user->length);
788 		break;
789 	}
790 
791 	case MEMREADOOB64:
792 	{
793 		struct mtd_oob_buf64 buf;
794 		struct mtd_oob_buf64 __user *buf_user = argp;
795 
796 		if (copy_from_user(&buf, argp, sizeof(buf)))
797 			ret = -EFAULT;
798 		else
799 			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
800 				(void __user *)(uintptr_t)buf.usr_ptr,
801 				&buf_user->length);
802 		break;
803 	}
804 
805 	case MEMWRITE:
806 	{
807 		ret = mtdchar_write_ioctl(mtd,
808 		      (struct mtd_write_req __user *)arg);
809 		break;
810 	}
811 
812 	case MEMLOCK:
813 	{
814 		struct erase_info_user einfo;
815 
816 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
817 			return -EFAULT;
818 
819 		if (!mtd->lock)
820 			ret = -EOPNOTSUPP;
821 		else
822 			ret = mtd_lock(mtd, einfo.start, einfo.length);
823 		break;
824 	}
825 
826 	case MEMUNLOCK:
827 	{
828 		struct erase_info_user einfo;
829 
830 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
831 			return -EFAULT;
832 
833 		if (!mtd->unlock)
834 			ret = -EOPNOTSUPP;
835 		else
836 			ret = mtd_unlock(mtd, einfo.start, einfo.length);
837 		break;
838 	}
839 
840 	case MEMISLOCKED:
841 	{
842 		struct erase_info_user einfo;
843 
844 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
845 			return -EFAULT;
846 
847 		if (!mtd->is_locked)
848 			ret = -EOPNOTSUPP;
849 		else
850 			ret = mtd_is_locked(mtd, einfo.start, einfo.length);
851 		break;
852 	}
853 
854 	/* Legacy interface */
855 	case MEMGETOOBSEL:
856 	{
857 		struct nand_oobinfo oi;
858 
859 		if (!mtd->ecclayout)
860 			return -EOPNOTSUPP;
861 		if (mtd->ecclayout->eccbytes > ARRAY_SIZE(oi.eccpos))
862 			return -EINVAL;
863 
864 		oi.useecc = MTD_NANDECC_AUTOPLACE;
865 		memcpy(&oi.eccpos, mtd->ecclayout->eccpos, sizeof(oi.eccpos));
866 		memcpy(&oi.oobfree, mtd->ecclayout->oobfree,
867 		       sizeof(oi.oobfree));
868 		oi.eccbytes = mtd->ecclayout->eccbytes;
869 
870 		if (copy_to_user(argp, &oi, sizeof(struct nand_oobinfo)))
871 			return -EFAULT;
872 		break;
873 	}
874 
875 	case MEMGETBADBLOCK:
876 	{
877 		loff_t offs;
878 
879 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
880 			return -EFAULT;
881 		if (!mtd->block_isbad)
882 			ret = -EOPNOTSUPP;
883 		else
884 			return mtd_block_isbad(mtd, offs);
885 		break;
886 	}
887 
888 	case MEMSETBADBLOCK:
889 	{
890 		loff_t offs;
891 
892 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
893 			return -EFAULT;
894 		if (!mtd->block_markbad)
895 			ret = -EOPNOTSUPP;
896 		else
897 			return mtd_block_markbad(mtd, offs);
898 		break;
899 	}
900 
901 #ifdef CONFIG_HAVE_MTD_OTP
902 	case OTPSELECT:
903 	{
904 		int mode;
905 		if (copy_from_user(&mode, argp, sizeof(int)))
906 			return -EFAULT;
907 
908 		mfi->mode = MTD_FILE_MODE_NORMAL;
909 
910 		ret = otp_select_filemode(mfi, mode);
911 
912 		file->f_pos = 0;
913 		break;
914 	}
915 
916 	case OTPGETREGIONCOUNT:
917 	case OTPGETREGIONINFO:
918 	{
919 		struct otp_info *buf = kmalloc(4096, GFP_KERNEL);
920 		if (!buf)
921 			return -ENOMEM;
922 		ret = -EOPNOTSUPP;
923 		switch (mfi->mode) {
924 		case MTD_FILE_MODE_OTP_FACTORY:
925 			if (mtd->get_fact_prot_info)
926 				ret = mtd_get_fact_prot_info(mtd, buf, 4096);
927 			break;
928 		case MTD_FILE_MODE_OTP_USER:
929 			if (mtd->get_user_prot_info)
930 				ret = mtd_get_user_prot_info(mtd, buf, 4096);
931 			break;
932 		default:
933 			break;
934 		}
935 		if (ret >= 0) {
936 			if (cmd == OTPGETREGIONCOUNT) {
937 				int nbr = ret / sizeof(struct otp_info);
938 				ret = copy_to_user(argp, &nbr, sizeof(int));
939 			} else
940 				ret = copy_to_user(argp, buf, ret);
941 			if (ret)
942 				ret = -EFAULT;
943 		}
944 		kfree(buf);
945 		break;
946 	}
947 
948 	case OTPLOCK:
949 	{
950 		struct otp_info oinfo;
951 
952 		if (mfi->mode != MTD_FILE_MODE_OTP_USER)
953 			return -EINVAL;
954 		if (copy_from_user(&oinfo, argp, sizeof(oinfo)))
955 			return -EFAULT;
956 		if (!mtd->lock_user_prot_reg)
957 			return -EOPNOTSUPP;
958 		ret = mtd_lock_user_prot_reg(mtd, oinfo.start, oinfo.length);
959 		break;
960 	}
961 #endif
962 
963 	/* This ioctl is being deprecated - it truncates the ECC layout */
964 	case ECCGETLAYOUT:
965 	{
966 		struct nand_ecclayout_user *usrlay;
967 
968 		if (!mtd->ecclayout)
969 			return -EOPNOTSUPP;
970 
971 		usrlay = kmalloc(sizeof(*usrlay), GFP_KERNEL);
972 		if (!usrlay)
973 			return -ENOMEM;
974 
975 		shrink_ecclayout(mtd->ecclayout, usrlay);
976 
977 		if (copy_to_user(argp, usrlay, sizeof(*usrlay)))
978 			ret = -EFAULT;
979 		kfree(usrlay);
980 		break;
981 	}
982 
983 	case ECCGETSTATS:
984 	{
985 		if (copy_to_user(argp, &mtd->ecc_stats,
986 				 sizeof(struct mtd_ecc_stats)))
987 			return -EFAULT;
988 		break;
989 	}
990 
991 	case MTDFILEMODE:
992 	{
993 		mfi->mode = 0;
994 
995 		switch(arg) {
996 		case MTD_FILE_MODE_OTP_FACTORY:
997 		case MTD_FILE_MODE_OTP_USER:
998 			ret = otp_select_filemode(mfi, arg);
999 			break;
1000 
1001 		case MTD_FILE_MODE_RAW:
1002 			if (!mtd_has_oob(mtd))
1003 				return -EOPNOTSUPP;
1004 			mfi->mode = arg;
1005 
1006 		case MTD_FILE_MODE_NORMAL:
1007 			break;
1008 		default:
1009 			ret = -EINVAL;
1010 		}
1011 		file->f_pos = 0;
1012 		break;
1013 	}
1014 
1015 	case BLKPG:
1016 	{
1017 		ret = mtdchar_blkpg_ioctl(mtd,
1018 		      (struct blkpg_ioctl_arg __user *)arg);
1019 		break;
1020 	}
1021 
1022 	case BLKRRPART:
1023 	{
1024 		/* No reread partition feature. Just return ok */
1025 		ret = 0;
1026 		break;
1027 	}
1028 
1029 	default:
1030 		ret = -ENOTTY;
1031 	}
1032 
1033 	return ret;
1034 } /* memory_ioctl */
1035 
1036 static long mtdchar_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
1037 {
1038 	int ret;
1039 
1040 	mutex_lock(&mtd_mutex);
1041 	ret = mtdchar_ioctl(file, cmd, arg);
1042 	mutex_unlock(&mtd_mutex);
1043 
1044 	return ret;
1045 }
1046 
1047 #ifdef CONFIG_COMPAT
1048 
1049 struct mtd_oob_buf32 {
1050 	u_int32_t start;
1051 	u_int32_t length;
1052 	compat_caddr_t ptr;	/* unsigned char* */
1053 };
1054 
1055 #define MEMWRITEOOB32		_IOWR('M', 3, struct mtd_oob_buf32)
1056 #define MEMREADOOB32		_IOWR('M', 4, struct mtd_oob_buf32)
1057 
1058 static long mtdchar_compat_ioctl(struct file *file, unsigned int cmd,
1059 	unsigned long arg)
1060 {
1061 	struct mtd_file_info *mfi = file->private_data;
1062 	struct mtd_info *mtd = mfi->mtd;
1063 	void __user *argp = compat_ptr(arg);
1064 	int ret = 0;
1065 
1066 	mutex_lock(&mtd_mutex);
1067 
1068 	switch (cmd) {
1069 	case MEMWRITEOOB32:
1070 	{
1071 		struct mtd_oob_buf32 buf;
1072 		struct mtd_oob_buf32 __user *buf_user = argp;
1073 
1074 		if (copy_from_user(&buf, argp, sizeof(buf)))
1075 			ret = -EFAULT;
1076 		else
1077 			ret = mtdchar_writeoob(file, mtd, buf.start,
1078 				buf.length, compat_ptr(buf.ptr),
1079 				&buf_user->length);
1080 		break;
1081 	}
1082 
1083 	case MEMREADOOB32:
1084 	{
1085 		struct mtd_oob_buf32 buf;
1086 		struct mtd_oob_buf32 __user *buf_user = argp;
1087 
1088 		/* NOTE: writes return length to buf->start */
1089 		if (copy_from_user(&buf, argp, sizeof(buf)))
1090 			ret = -EFAULT;
1091 		else
1092 			ret = mtdchar_readoob(file, mtd, buf.start,
1093 				buf.length, compat_ptr(buf.ptr),
1094 				&buf_user->start);
1095 		break;
1096 	}
1097 	default:
1098 		ret = mtdchar_ioctl(file, cmd, (unsigned long)argp);
1099 	}
1100 
1101 	mutex_unlock(&mtd_mutex);
1102 
1103 	return ret;
1104 }
1105 
1106 #endif /* CONFIG_COMPAT */
1107 
1108 /*
1109  * try to determine where a shared mapping can be made
1110  * - only supported for NOMMU at the moment (MMU can't doesn't copy private
1111  *   mappings)
1112  */
1113 #ifndef CONFIG_MMU
1114 static unsigned long mtdchar_get_unmapped_area(struct file *file,
1115 					   unsigned long addr,
1116 					   unsigned long len,
1117 					   unsigned long pgoff,
1118 					   unsigned long flags)
1119 {
1120 	struct mtd_file_info *mfi = file->private_data;
1121 	struct mtd_info *mtd = mfi->mtd;
1122 	unsigned long offset;
1123 	int ret;
1124 
1125 	if (addr != 0)
1126 		return (unsigned long) -EINVAL;
1127 
1128 	if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT))
1129 		return (unsigned long) -EINVAL;
1130 
1131 	offset = pgoff << PAGE_SHIFT;
1132 	if (offset > mtd->size - len)
1133 		return (unsigned long) -EINVAL;
1134 
1135 	ret = mtd_get_unmapped_area(mtd, len, offset, flags);
1136 	return ret == -EOPNOTSUPP ? -ENOSYS : ret;
1137 }
1138 #endif
1139 
1140 /*
1141  * set up a mapping for shared memory segments
1142  */
1143 static int mtdchar_mmap(struct file *file, struct vm_area_struct *vma)
1144 {
1145 #ifdef CONFIG_MMU
1146 	struct mtd_file_info *mfi = file->private_data;
1147 	struct mtd_info *mtd = mfi->mtd;
1148 	struct map_info *map = mtd->priv;
1149 	unsigned long start;
1150 	unsigned long off;
1151 	u32 len;
1152 
1153 	if (mtd->type == MTD_RAM || mtd->type == MTD_ROM) {
1154 		off = vma->vm_pgoff << PAGE_SHIFT;
1155 		start = map->phys;
1156 		len = PAGE_ALIGN((start & ~PAGE_MASK) + map->size);
1157 		start &= PAGE_MASK;
1158 		if ((vma->vm_end - vma->vm_start + off) > len)
1159 			return -EINVAL;
1160 
1161 		off += start;
1162 		vma->vm_pgoff = off >> PAGE_SHIFT;
1163 		vma->vm_flags |= VM_IO | VM_RESERVED;
1164 
1165 #ifdef pgprot_noncached
1166 		if (file->f_flags & O_DSYNC || off >= __pa(high_memory))
1167 			vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1168 #endif
1169 		if (io_remap_pfn_range(vma, vma->vm_start, off >> PAGE_SHIFT,
1170 				       vma->vm_end - vma->vm_start,
1171 				       vma->vm_page_prot))
1172 			return -EAGAIN;
1173 
1174 		return 0;
1175 	}
1176 	return -ENOSYS;
1177 #else
1178 	return vma->vm_flags & VM_SHARED ? 0 : -ENOSYS;
1179 #endif
1180 }
1181 
1182 static const struct file_operations mtd_fops = {
1183 	.owner		= THIS_MODULE,
1184 	.llseek		= mtdchar_lseek,
1185 	.read		= mtdchar_read,
1186 	.write		= mtdchar_write,
1187 	.unlocked_ioctl	= mtdchar_unlocked_ioctl,
1188 #ifdef CONFIG_COMPAT
1189 	.compat_ioctl	= mtdchar_compat_ioctl,
1190 #endif
1191 	.open		= mtdchar_open,
1192 	.release	= mtdchar_close,
1193 	.mmap		= mtdchar_mmap,
1194 #ifndef CONFIG_MMU
1195 	.get_unmapped_area = mtdchar_get_unmapped_area,
1196 #endif
1197 };
1198 
1199 static struct dentry *mtd_inodefs_mount(struct file_system_type *fs_type,
1200 				int flags, const char *dev_name, void *data)
1201 {
1202 	return mount_pseudo(fs_type, "mtd_inode:", NULL, NULL, MTD_INODE_FS_MAGIC);
1203 }
1204 
1205 static struct file_system_type mtd_inodefs_type = {
1206        .name = "mtd_inodefs",
1207        .mount = mtd_inodefs_mount,
1208        .kill_sb = kill_anon_super,
1209 };
1210 
1211 static void mtdchar_notify_add(struct mtd_info *mtd)
1212 {
1213 }
1214 
1215 static void mtdchar_notify_remove(struct mtd_info *mtd)
1216 {
1217 	struct inode *mtd_ino = ilookup(mtd_inode_mnt->mnt_sb, mtd->index);
1218 
1219 	if (mtd_ino) {
1220 		/* Destroy the inode if it exists */
1221 		clear_nlink(mtd_ino);
1222 		iput(mtd_ino);
1223 	}
1224 }
1225 
1226 static struct mtd_notifier mtdchar_notifier = {
1227 	.add = mtdchar_notify_add,
1228 	.remove = mtdchar_notify_remove,
1229 };
1230 
1231 static int __init init_mtdchar(void)
1232 {
1233 	int ret;
1234 
1235 	ret = __register_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS,
1236 				   "mtd", &mtd_fops);
1237 	if (ret < 0) {
1238 		pr_notice("Can't allocate major number %d for "
1239 				"Memory Technology Devices.\n", MTD_CHAR_MAJOR);
1240 		return ret;
1241 	}
1242 
1243 	ret = register_filesystem(&mtd_inodefs_type);
1244 	if (ret) {
1245 		pr_notice("Can't register mtd_inodefs filesystem: %d\n", ret);
1246 		goto err_unregister_chdev;
1247 	}
1248 
1249 	mtd_inode_mnt = kern_mount(&mtd_inodefs_type);
1250 	if (IS_ERR(mtd_inode_mnt)) {
1251 		ret = PTR_ERR(mtd_inode_mnt);
1252 		pr_notice("Error mounting mtd_inodefs filesystem: %d\n", ret);
1253 		goto err_unregister_filesystem;
1254 	}
1255 	register_mtd_user(&mtdchar_notifier);
1256 
1257 	return ret;
1258 
1259 err_unregister_filesystem:
1260 	unregister_filesystem(&mtd_inodefs_type);
1261 err_unregister_chdev:
1262 	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1263 	return ret;
1264 }
1265 
1266 static void __exit cleanup_mtdchar(void)
1267 {
1268 	unregister_mtd_user(&mtdchar_notifier);
1269 	kern_unmount(mtd_inode_mnt);
1270 	unregister_filesystem(&mtd_inodefs_type);
1271 	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1272 }
1273 
1274 module_init(init_mtdchar);
1275 module_exit(cleanup_mtdchar);
1276 
1277 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);
1278 
1279 MODULE_LICENSE("GPL");
1280 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
1281 MODULE_DESCRIPTION("Direct character-device access to MTD devices");
1282 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);
1283