xref: /linux/drivers/mtd/mtdchar.c (revision 9e8238020c5beba64e7ffafbb7ea0fb02fe68270)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
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/mutex.h>
16 #include <linux/backing-dev.h>
17 #include <linux/compat.h>
18 #include <linux/mount.h>
19 #include <linux/blkpg.h>
20 #include <linux/magic.h>
21 #include <linux/major.h>
22 #include <linux/mtd/mtd.h>
23 #include <linux/mtd/partitions.h>
24 #include <linux/mtd/map.h>
25 
26 #include <linux/uaccess.h>
27 
28 #include "mtdcore.h"
29 
30 static DEFINE_MUTEX(mtd_mutex);
31 
32 /*
33  * Data structure to hold the pointer to the mtd device as well
34  * as mode information of various use cases.
35  */
36 struct mtd_file_info {
37 	struct mtd_info *mtd;
38 	enum mtd_file_modes mode;
39 };
40 
41 static loff_t mtdchar_lseek(struct file *file, loff_t offset, int orig)
42 {
43 	struct mtd_file_info *mfi = file->private_data;
44 	return fixed_size_llseek(file, offset, orig, mfi->mtd->size);
45 }
46 
47 static int mtdchar_open(struct inode *inode, struct file *file)
48 {
49 	int minor = iminor(inode);
50 	int devnum = minor >> 1;
51 	int ret = 0;
52 	struct mtd_info *mtd;
53 	struct mtd_file_info *mfi;
54 
55 	pr_debug("MTD_open\n");
56 
57 	/* You can't open the RO devices RW */
58 	if ((file->f_mode & FMODE_WRITE) && (minor & 1))
59 		return -EACCES;
60 
61 	mutex_lock(&mtd_mutex);
62 	mtd = get_mtd_device(NULL, devnum);
63 
64 	if (IS_ERR(mtd)) {
65 		ret = PTR_ERR(mtd);
66 		goto out;
67 	}
68 
69 	if (mtd->type == MTD_ABSENT) {
70 		ret = -ENODEV;
71 		goto out1;
72 	}
73 
74 	/* You can't open it RW if it's not a writeable device */
75 	if ((file->f_mode & FMODE_WRITE) && !(mtd->flags & MTD_WRITEABLE)) {
76 		ret = -EACCES;
77 		goto out1;
78 	}
79 
80 	mfi = kzalloc(sizeof(*mfi), GFP_KERNEL);
81 	if (!mfi) {
82 		ret = -ENOMEM;
83 		goto out1;
84 	}
85 	mfi->mtd = mtd;
86 	file->private_data = mfi;
87 	mutex_unlock(&mtd_mutex);
88 	return 0;
89 
90 out1:
91 	put_mtd_device(mtd);
92 out:
93 	mutex_unlock(&mtd_mutex);
94 	return ret;
95 } /* mtdchar_open */
96 
97 /*====================================================================*/
98 
99 static int mtdchar_close(struct inode *inode, struct file *file)
100 {
101 	struct mtd_file_info *mfi = file->private_data;
102 	struct mtd_info *mtd = mfi->mtd;
103 
104 	pr_debug("MTD_close\n");
105 
106 	/* Only sync if opened RW */
107 	if ((file->f_mode & FMODE_WRITE))
108 		mtd_sync(mtd);
109 
110 	put_mtd_device(mtd);
111 	file->private_data = NULL;
112 	kfree(mfi);
113 
114 	return 0;
115 } /* mtdchar_close */
116 
117 /* Back in June 2001, dwmw2 wrote:
118  *
119  *   FIXME: This _really_ needs to die. In 2.5, we should lock the
120  *   userspace buffer down and use it directly with readv/writev.
121  *
122  * The implementation below, using mtd_kmalloc_up_to, mitigates
123  * allocation failures when the system is under low-memory situations
124  * or if memory is highly fragmented at the cost of reducing the
125  * performance of the requested transfer due to a smaller buffer size.
126  *
127  * A more complex but more memory-efficient implementation based on
128  * get_user_pages and iovecs to cover extents of those pages is a
129  * longer-term goal, as intimated by dwmw2 above. However, for the
130  * write case, this requires yet more complex head and tail transfer
131  * handling when those head and tail offsets and sizes are such that
132  * alignment requirements are not met in the NAND subdriver.
133  */
134 
135 static ssize_t mtdchar_read(struct file *file, char __user *buf, size_t count,
136 			loff_t *ppos)
137 {
138 	struct mtd_file_info *mfi = file->private_data;
139 	struct mtd_info *mtd = mfi->mtd;
140 	size_t retlen;
141 	size_t total_retlen=0;
142 	int ret=0;
143 	int len;
144 	size_t size = count;
145 	char *kbuf;
146 
147 	pr_debug("MTD_read\n");
148 
149 	if (*ppos + count > mtd->size) {
150 		if (*ppos < mtd->size)
151 			count = mtd->size - *ppos;
152 		else
153 			count = 0;
154 	}
155 
156 	if (!count)
157 		return 0;
158 
159 	kbuf = mtd_kmalloc_up_to(mtd, &size);
160 	if (!kbuf)
161 		return -ENOMEM;
162 
163 	while (count) {
164 		len = min_t(size_t, count, size);
165 
166 		switch (mfi->mode) {
167 		case MTD_FILE_MODE_OTP_FACTORY:
168 			ret = mtd_read_fact_prot_reg(mtd, *ppos, len,
169 						     &retlen, kbuf);
170 			break;
171 		case MTD_FILE_MODE_OTP_USER:
172 			ret = mtd_read_user_prot_reg(mtd, *ppos, len,
173 						     &retlen, kbuf);
174 			break;
175 		case MTD_FILE_MODE_RAW:
176 		{
177 			struct mtd_oob_ops ops = {};
178 
179 			ops.mode = MTD_OPS_RAW;
180 			ops.datbuf = kbuf;
181 			ops.oobbuf = NULL;
182 			ops.len = len;
183 
184 			ret = mtd_read_oob(mtd, *ppos, &ops);
185 			retlen = ops.retlen;
186 			break;
187 		}
188 		default:
189 			ret = mtd_read(mtd, *ppos, len, &retlen, kbuf);
190 		}
191 		/* Nand returns -EBADMSG on ECC errors, but it returns
192 		 * the data. For our userspace tools it is important
193 		 * to dump areas with ECC errors!
194 		 * For kernel internal usage it also might return -EUCLEAN
195 		 * to signal the caller that a bitflip has occurred and has
196 		 * been corrected by the ECC algorithm.
197 		 * Userspace software which accesses NAND this way
198 		 * must be aware of the fact that it deals with NAND
199 		 */
200 		if (!ret || mtd_is_bitflip_or_eccerr(ret)) {
201 			*ppos += retlen;
202 			if (copy_to_user(buf, kbuf, retlen)) {
203 				kfree(kbuf);
204 				return -EFAULT;
205 			}
206 			else
207 				total_retlen += retlen;
208 
209 			count -= retlen;
210 			buf += retlen;
211 			if (retlen == 0)
212 				count = 0;
213 		}
214 		else {
215 			kfree(kbuf);
216 			return ret;
217 		}
218 
219 	}
220 
221 	kfree(kbuf);
222 	return total_retlen;
223 } /* mtdchar_read */
224 
225 static ssize_t mtdchar_write(struct file *file, const char __user *buf, size_t count,
226 			loff_t *ppos)
227 {
228 	struct mtd_file_info *mfi = file->private_data;
229 	struct mtd_info *mtd = mfi->mtd;
230 	size_t size = count;
231 	char *kbuf;
232 	size_t retlen;
233 	size_t total_retlen=0;
234 	int ret=0;
235 	int len;
236 
237 	pr_debug("MTD_write\n");
238 
239 	if (*ppos >= mtd->size)
240 		return -ENOSPC;
241 
242 	if (*ppos + count > mtd->size)
243 		count = mtd->size - *ppos;
244 
245 	if (!count)
246 		return 0;
247 
248 	kbuf = mtd_kmalloc_up_to(mtd, &size);
249 	if (!kbuf)
250 		return -ENOMEM;
251 
252 	while (count) {
253 		len = min_t(size_t, count, size);
254 
255 		if (copy_from_user(kbuf, buf, len)) {
256 			kfree(kbuf);
257 			return -EFAULT;
258 		}
259 
260 		switch (mfi->mode) {
261 		case MTD_FILE_MODE_OTP_FACTORY:
262 			ret = -EROFS;
263 			break;
264 		case MTD_FILE_MODE_OTP_USER:
265 			ret = mtd_write_user_prot_reg(mtd, *ppos, len,
266 						      &retlen, kbuf);
267 			break;
268 
269 		case MTD_FILE_MODE_RAW:
270 		{
271 			struct mtd_oob_ops ops = {};
272 
273 			ops.mode = MTD_OPS_RAW;
274 			ops.datbuf = kbuf;
275 			ops.oobbuf = NULL;
276 			ops.ooboffs = 0;
277 			ops.len = len;
278 
279 			ret = mtd_write_oob(mtd, *ppos, &ops);
280 			retlen = ops.retlen;
281 			break;
282 		}
283 
284 		default:
285 			ret = mtd_write(mtd, *ppos, len, &retlen, kbuf);
286 		}
287 
288 		/*
289 		 * Return -ENOSPC only if no data could be written at all.
290 		 * Otherwise just return the number of bytes that actually
291 		 * have been written.
292 		 */
293 		if ((ret == -ENOSPC) && (total_retlen))
294 			break;
295 
296 		if (!ret) {
297 			*ppos += retlen;
298 			total_retlen += retlen;
299 			count -= retlen;
300 			buf += retlen;
301 		}
302 		else {
303 			kfree(kbuf);
304 			return ret;
305 		}
306 	}
307 
308 	kfree(kbuf);
309 	return total_retlen;
310 } /* mtdchar_write */
311 
312 /*======================================================================
313 
314     IOCTL calls for getting device parameters.
315 
316 ======================================================================*/
317 
318 static int otp_select_filemode(struct mtd_file_info *mfi, int mode)
319 {
320 	struct mtd_info *mtd = mfi->mtd;
321 	size_t retlen;
322 
323 	switch (mode) {
324 	case MTD_OTP_FACTORY:
325 		if (mtd_read_fact_prot_reg(mtd, -1, 0, &retlen, NULL) ==
326 				-EOPNOTSUPP)
327 			return -EOPNOTSUPP;
328 
329 		mfi->mode = MTD_FILE_MODE_OTP_FACTORY;
330 		break;
331 	case MTD_OTP_USER:
332 		if (mtd_read_user_prot_reg(mtd, -1, 0, &retlen, NULL) ==
333 				-EOPNOTSUPP)
334 			return -EOPNOTSUPP;
335 
336 		mfi->mode = MTD_FILE_MODE_OTP_USER;
337 		break;
338 	case MTD_OTP_OFF:
339 		mfi->mode = MTD_FILE_MODE_NORMAL;
340 		break;
341 	default:
342 		return -EINVAL;
343 	}
344 
345 	return 0;
346 }
347 
348 static int mtdchar_writeoob(struct file *file, struct mtd_info *mtd,
349 	uint64_t start, uint32_t length, void __user *ptr,
350 	uint32_t __user *retp)
351 {
352 	struct mtd_info *master  = mtd_get_master(mtd);
353 	struct mtd_file_info *mfi = file->private_data;
354 	struct mtd_oob_ops ops = {};
355 	uint32_t retlen;
356 	int ret = 0;
357 
358 	if (!(file->f_mode & FMODE_WRITE))
359 		return -EPERM;
360 
361 	if (length > 4096)
362 		return -EINVAL;
363 
364 	if (!master->_write_oob)
365 		return -EOPNOTSUPP;
366 
367 	ops.ooblen = length;
368 	ops.ooboffs = start & (mtd->writesize - 1);
369 	ops.datbuf = NULL;
370 	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
371 		MTD_OPS_PLACE_OOB;
372 
373 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
374 		return -EINVAL;
375 
376 	ops.oobbuf = memdup_user(ptr, length);
377 	if (IS_ERR(ops.oobbuf))
378 		return PTR_ERR(ops.oobbuf);
379 
380 	start &= ~((uint64_t)mtd->writesize - 1);
381 	ret = mtd_write_oob(mtd, start, &ops);
382 
383 	if (ops.oobretlen > 0xFFFFFFFFU)
384 		ret = -EOVERFLOW;
385 	retlen = ops.oobretlen;
386 	if (copy_to_user(retp, &retlen, sizeof(length)))
387 		ret = -EFAULT;
388 
389 	kfree(ops.oobbuf);
390 	return ret;
391 }
392 
393 static int mtdchar_readoob(struct file *file, struct mtd_info *mtd,
394 	uint64_t start, uint32_t length, void __user *ptr,
395 	uint32_t __user *retp)
396 {
397 	struct mtd_file_info *mfi = file->private_data;
398 	struct mtd_oob_ops ops = {};
399 	int ret = 0;
400 
401 	if (length > 4096)
402 		return -EINVAL;
403 
404 	ops.ooblen = length;
405 	ops.ooboffs = start & (mtd->writesize - 1);
406 	ops.datbuf = NULL;
407 	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
408 		MTD_OPS_PLACE_OOB;
409 
410 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
411 		return -EINVAL;
412 
413 	ops.oobbuf = kmalloc(length, GFP_KERNEL);
414 	if (!ops.oobbuf)
415 		return -ENOMEM;
416 
417 	start &= ~((uint64_t)mtd->writesize - 1);
418 	ret = mtd_read_oob(mtd, start, &ops);
419 
420 	if (put_user(ops.oobretlen, retp))
421 		ret = -EFAULT;
422 	else if (ops.oobretlen && copy_to_user(ptr, ops.oobbuf,
423 					    ops.oobretlen))
424 		ret = -EFAULT;
425 
426 	kfree(ops.oobbuf);
427 
428 	/*
429 	 * NAND returns -EBADMSG on ECC errors, but it returns the OOB
430 	 * data. For our userspace tools it is important to dump areas
431 	 * with ECC errors!
432 	 * For kernel internal usage it also might return -EUCLEAN
433 	 * to signal the caller that a bitflip has occurred and has
434 	 * been corrected by the ECC algorithm.
435 	 *
436 	 * Note: currently the standard NAND function, nand_read_oob_std,
437 	 * does not calculate ECC for the OOB area, so do not rely on
438 	 * this behavior unless you have replaced it with your own.
439 	 */
440 	if (mtd_is_bitflip_or_eccerr(ret))
441 		return 0;
442 
443 	return ret;
444 }
445 
446 /*
447  * Copies (and truncates, if necessary) OOB layout information to the
448  * deprecated layout struct, nand_ecclayout_user. This is necessary only to
449  * support the deprecated API ioctl ECCGETLAYOUT while allowing all new
450  * functionality to use mtd_ooblayout_ops flexibly (i.e. mtd_ooblayout_ops
451  * can describe any kind of OOB layout with almost zero overhead from a
452  * memory usage point of view).
453  */
454 static int shrink_ecclayout(struct mtd_info *mtd,
455 			    struct nand_ecclayout_user *to)
456 {
457 	struct mtd_oob_region oobregion;
458 	int i, section = 0, ret;
459 
460 	if (!mtd || !to)
461 		return -EINVAL;
462 
463 	memset(to, 0, sizeof(*to));
464 
465 	to->eccbytes = 0;
466 	for (i = 0; i < MTD_MAX_ECCPOS_ENTRIES;) {
467 		u32 eccpos;
468 
469 		ret = mtd_ooblayout_ecc(mtd, section++, &oobregion);
470 		if (ret < 0) {
471 			if (ret != -ERANGE)
472 				return ret;
473 
474 			break;
475 		}
476 
477 		eccpos = oobregion.offset;
478 		for (; i < MTD_MAX_ECCPOS_ENTRIES &&
479 		       eccpos < oobregion.offset + oobregion.length; i++) {
480 			to->eccpos[i] = eccpos++;
481 			to->eccbytes++;
482 		}
483 	}
484 
485 	for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES; i++) {
486 		ret = mtd_ooblayout_free(mtd, i, &oobregion);
487 		if (ret < 0) {
488 			if (ret != -ERANGE)
489 				return ret;
490 
491 			break;
492 		}
493 
494 		to->oobfree[i].offset = oobregion.offset;
495 		to->oobfree[i].length = oobregion.length;
496 		to->oobavail += to->oobfree[i].length;
497 	}
498 
499 	return 0;
500 }
501 
502 static int get_oobinfo(struct mtd_info *mtd, struct nand_oobinfo *to)
503 {
504 	struct mtd_oob_region oobregion;
505 	int i, section = 0, ret;
506 
507 	if (!mtd || !to)
508 		return -EINVAL;
509 
510 	memset(to, 0, sizeof(*to));
511 
512 	to->eccbytes = 0;
513 	for (i = 0; i < ARRAY_SIZE(to->eccpos);) {
514 		u32 eccpos;
515 
516 		ret = mtd_ooblayout_ecc(mtd, section++, &oobregion);
517 		if (ret < 0) {
518 			if (ret != -ERANGE)
519 				return ret;
520 
521 			break;
522 		}
523 
524 		if (oobregion.length + i > ARRAY_SIZE(to->eccpos))
525 			return -EINVAL;
526 
527 		eccpos = oobregion.offset;
528 		for (; eccpos < oobregion.offset + oobregion.length; i++) {
529 			to->eccpos[i] = eccpos++;
530 			to->eccbytes++;
531 		}
532 	}
533 
534 	for (i = 0; i < 8; i++) {
535 		ret = mtd_ooblayout_free(mtd, i, &oobregion);
536 		if (ret < 0) {
537 			if (ret != -ERANGE)
538 				return ret;
539 
540 			break;
541 		}
542 
543 		to->oobfree[i][0] = oobregion.offset;
544 		to->oobfree[i][1] = oobregion.length;
545 	}
546 
547 	to->useecc = MTD_NANDECC_AUTOPLACE;
548 
549 	return 0;
550 }
551 
552 static int mtdchar_blkpg_ioctl(struct mtd_info *mtd,
553 			       struct blkpg_ioctl_arg *arg)
554 {
555 	struct blkpg_partition p;
556 
557 	if (!capable(CAP_SYS_ADMIN))
558 		return -EPERM;
559 
560 	if (copy_from_user(&p, arg->data, sizeof(p)))
561 		return -EFAULT;
562 
563 	switch (arg->op) {
564 	case BLKPG_ADD_PARTITION:
565 
566 		/* Only master mtd device must be used to add partitions */
567 		if (mtd_is_partition(mtd))
568 			return -EINVAL;
569 
570 		/* Sanitize user input */
571 		p.devname[BLKPG_DEVNAMELTH - 1] = '\0';
572 
573 		return mtd_add_partition(mtd, p.devname, p.start, p.length);
574 
575 	case BLKPG_DEL_PARTITION:
576 
577 		if (p.pno < 0)
578 			return -EINVAL;
579 
580 		return mtd_del_partition(mtd, p.pno);
581 
582 	default:
583 		return -EINVAL;
584 	}
585 }
586 
587 static int mtdchar_write_ioctl(struct mtd_info *mtd,
588 		struct mtd_write_req __user *argp)
589 {
590 	struct mtd_info *master = mtd_get_master(mtd);
591 	struct mtd_write_req req;
592 	struct mtd_oob_ops ops = {};
593 	const void __user *usr_data, *usr_oob;
594 	int ret;
595 
596 	if (copy_from_user(&req, argp, sizeof(req)))
597 		return -EFAULT;
598 
599 	usr_data = (const void __user *)(uintptr_t)req.usr_data;
600 	usr_oob = (const void __user *)(uintptr_t)req.usr_oob;
601 
602 	if (!master->_write_oob)
603 		return -EOPNOTSUPP;
604 	ops.mode = req.mode;
605 	ops.len = (size_t)req.len;
606 	ops.ooblen = (size_t)req.ooblen;
607 	ops.ooboffs = 0;
608 
609 	if (usr_data) {
610 		ops.datbuf = memdup_user(usr_data, ops.len);
611 		if (IS_ERR(ops.datbuf))
612 			return PTR_ERR(ops.datbuf);
613 	} else {
614 		ops.datbuf = NULL;
615 	}
616 
617 	if (usr_oob) {
618 		ops.oobbuf = memdup_user(usr_oob, ops.ooblen);
619 		if (IS_ERR(ops.oobbuf)) {
620 			kfree(ops.datbuf);
621 			return PTR_ERR(ops.oobbuf);
622 		}
623 	} else {
624 		ops.oobbuf = NULL;
625 	}
626 
627 	ret = mtd_write_oob(mtd, (loff_t)req.start, &ops);
628 
629 	kfree(ops.datbuf);
630 	kfree(ops.oobbuf);
631 
632 	return ret;
633 }
634 
635 static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg)
636 {
637 	struct mtd_file_info *mfi = file->private_data;
638 	struct mtd_info *mtd = mfi->mtd;
639 	struct mtd_info *master = mtd_get_master(mtd);
640 	void __user *argp = (void __user *)arg;
641 	int ret = 0;
642 	struct mtd_info_user info;
643 
644 	pr_debug("MTD_ioctl\n");
645 
646 	switch (cmd) {
647 	case MEMGETREGIONCOUNT:
648 		if (copy_to_user(argp, &(mtd->numeraseregions), sizeof(int)))
649 			return -EFAULT;
650 		break;
651 
652 	case MEMGETREGIONINFO:
653 	{
654 		uint32_t ur_idx;
655 		struct mtd_erase_region_info *kr;
656 		struct region_info_user __user *ur = argp;
657 
658 		if (get_user(ur_idx, &(ur->regionindex)))
659 			return -EFAULT;
660 
661 		if (ur_idx >= mtd->numeraseregions)
662 			return -EINVAL;
663 
664 		kr = &(mtd->eraseregions[ur_idx]);
665 
666 		if (put_user(kr->offset, &(ur->offset))
667 		    || put_user(kr->erasesize, &(ur->erasesize))
668 		    || put_user(kr->numblocks, &(ur->numblocks)))
669 			return -EFAULT;
670 
671 		break;
672 	}
673 
674 	case MEMGETINFO:
675 		memset(&info, 0, sizeof(info));
676 		info.type	= mtd->type;
677 		info.flags	= mtd->flags;
678 		info.size	= mtd->size;
679 		info.erasesize	= mtd->erasesize;
680 		info.writesize	= mtd->writesize;
681 		info.oobsize	= mtd->oobsize;
682 		/* The below field is obsolete */
683 		info.padding	= 0;
684 		if (copy_to_user(argp, &info, sizeof(struct mtd_info_user)))
685 			return -EFAULT;
686 		break;
687 
688 	case MEMERASE:
689 	case MEMERASE64:
690 	{
691 		struct erase_info *erase;
692 
693 		if(!(file->f_mode & FMODE_WRITE))
694 			return -EPERM;
695 
696 		erase=kzalloc(sizeof(struct erase_info),GFP_KERNEL);
697 		if (!erase)
698 			ret = -ENOMEM;
699 		else {
700 			if (cmd == MEMERASE64) {
701 				struct erase_info_user64 einfo64;
702 
703 				if (copy_from_user(&einfo64, argp,
704 					    sizeof(struct erase_info_user64))) {
705 					kfree(erase);
706 					return -EFAULT;
707 				}
708 				erase->addr = einfo64.start;
709 				erase->len = einfo64.length;
710 			} else {
711 				struct erase_info_user einfo32;
712 
713 				if (copy_from_user(&einfo32, argp,
714 					    sizeof(struct erase_info_user))) {
715 					kfree(erase);
716 					return -EFAULT;
717 				}
718 				erase->addr = einfo32.start;
719 				erase->len = einfo32.length;
720 			}
721 
722 			ret = mtd_erase(mtd, erase);
723 			kfree(erase);
724 		}
725 		break;
726 	}
727 
728 	case MEMWRITEOOB:
729 	{
730 		struct mtd_oob_buf buf;
731 		struct mtd_oob_buf __user *buf_user = argp;
732 
733 		/* NOTE: writes return length to buf_user->length */
734 		if (copy_from_user(&buf, argp, sizeof(buf)))
735 			ret = -EFAULT;
736 		else
737 			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
738 				buf.ptr, &buf_user->length);
739 		break;
740 	}
741 
742 	case MEMREADOOB:
743 	{
744 		struct mtd_oob_buf buf;
745 		struct mtd_oob_buf __user *buf_user = argp;
746 
747 		/* NOTE: writes return length to buf_user->start */
748 		if (copy_from_user(&buf, argp, sizeof(buf)))
749 			ret = -EFAULT;
750 		else
751 			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
752 				buf.ptr, &buf_user->start);
753 		break;
754 	}
755 
756 	case MEMWRITEOOB64:
757 	{
758 		struct mtd_oob_buf64 buf;
759 		struct mtd_oob_buf64 __user *buf_user = argp;
760 
761 		if (copy_from_user(&buf, argp, sizeof(buf)))
762 			ret = -EFAULT;
763 		else
764 			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
765 				(void __user *)(uintptr_t)buf.usr_ptr,
766 				&buf_user->length);
767 		break;
768 	}
769 
770 	case MEMREADOOB64:
771 	{
772 		struct mtd_oob_buf64 buf;
773 		struct mtd_oob_buf64 __user *buf_user = argp;
774 
775 		if (copy_from_user(&buf, argp, sizeof(buf)))
776 			ret = -EFAULT;
777 		else
778 			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
779 				(void __user *)(uintptr_t)buf.usr_ptr,
780 				&buf_user->length);
781 		break;
782 	}
783 
784 	case MEMWRITE:
785 	{
786 		ret = mtdchar_write_ioctl(mtd,
787 		      (struct mtd_write_req __user *)arg);
788 		break;
789 	}
790 
791 	case MEMLOCK:
792 	{
793 		struct erase_info_user einfo;
794 
795 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
796 			return -EFAULT;
797 
798 		ret = mtd_lock(mtd, einfo.start, einfo.length);
799 		break;
800 	}
801 
802 	case MEMUNLOCK:
803 	{
804 		struct erase_info_user einfo;
805 
806 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
807 			return -EFAULT;
808 
809 		ret = mtd_unlock(mtd, einfo.start, einfo.length);
810 		break;
811 	}
812 
813 	case MEMISLOCKED:
814 	{
815 		struct erase_info_user einfo;
816 
817 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
818 			return -EFAULT;
819 
820 		ret = mtd_is_locked(mtd, einfo.start, einfo.length);
821 		break;
822 	}
823 
824 	/* Legacy interface */
825 	case MEMGETOOBSEL:
826 	{
827 		struct nand_oobinfo oi;
828 
829 		if (!master->ooblayout)
830 			return -EOPNOTSUPP;
831 
832 		ret = get_oobinfo(mtd, &oi);
833 		if (ret)
834 			return ret;
835 
836 		if (copy_to_user(argp, &oi, sizeof(struct nand_oobinfo)))
837 			return -EFAULT;
838 		break;
839 	}
840 
841 	case MEMGETBADBLOCK:
842 	{
843 		loff_t offs;
844 
845 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
846 			return -EFAULT;
847 		return mtd_block_isbad(mtd, offs);
848 		break;
849 	}
850 
851 	case MEMSETBADBLOCK:
852 	{
853 		loff_t offs;
854 
855 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
856 			return -EFAULT;
857 		return mtd_block_markbad(mtd, offs);
858 		break;
859 	}
860 
861 	case OTPSELECT:
862 	{
863 		int mode;
864 		if (copy_from_user(&mode, argp, sizeof(int)))
865 			return -EFAULT;
866 
867 		mfi->mode = MTD_FILE_MODE_NORMAL;
868 
869 		ret = otp_select_filemode(mfi, mode);
870 
871 		file->f_pos = 0;
872 		break;
873 	}
874 
875 	case OTPGETREGIONCOUNT:
876 	case OTPGETREGIONINFO:
877 	{
878 		struct otp_info *buf = kmalloc(4096, GFP_KERNEL);
879 		size_t retlen;
880 		if (!buf)
881 			return -ENOMEM;
882 		switch (mfi->mode) {
883 		case MTD_FILE_MODE_OTP_FACTORY:
884 			ret = mtd_get_fact_prot_info(mtd, 4096, &retlen, buf);
885 			break;
886 		case MTD_FILE_MODE_OTP_USER:
887 			ret = mtd_get_user_prot_info(mtd, 4096, &retlen, buf);
888 			break;
889 		default:
890 			ret = -EINVAL;
891 			break;
892 		}
893 		if (!ret) {
894 			if (cmd == OTPGETREGIONCOUNT) {
895 				int nbr = retlen / sizeof(struct otp_info);
896 				ret = copy_to_user(argp, &nbr, sizeof(int));
897 			} else
898 				ret = copy_to_user(argp, buf, retlen);
899 			if (ret)
900 				ret = -EFAULT;
901 		}
902 		kfree(buf);
903 		break;
904 	}
905 
906 	case OTPLOCK:
907 	{
908 		struct otp_info oinfo;
909 
910 		if (mfi->mode != MTD_FILE_MODE_OTP_USER)
911 			return -EINVAL;
912 		if (copy_from_user(&oinfo, argp, sizeof(oinfo)))
913 			return -EFAULT;
914 		ret = mtd_lock_user_prot_reg(mtd, oinfo.start, oinfo.length);
915 		break;
916 	}
917 
918 	/* This ioctl is being deprecated - it truncates the ECC layout */
919 	case ECCGETLAYOUT:
920 	{
921 		struct nand_ecclayout_user *usrlay;
922 
923 		if (!master->ooblayout)
924 			return -EOPNOTSUPP;
925 
926 		usrlay = kmalloc(sizeof(*usrlay), GFP_KERNEL);
927 		if (!usrlay)
928 			return -ENOMEM;
929 
930 		shrink_ecclayout(mtd, usrlay);
931 
932 		if (copy_to_user(argp, usrlay, sizeof(*usrlay)))
933 			ret = -EFAULT;
934 		kfree(usrlay);
935 		break;
936 	}
937 
938 	case ECCGETSTATS:
939 	{
940 		if (copy_to_user(argp, &mtd->ecc_stats,
941 				 sizeof(struct mtd_ecc_stats)))
942 			return -EFAULT;
943 		break;
944 	}
945 
946 	case MTDFILEMODE:
947 	{
948 		mfi->mode = 0;
949 
950 		switch(arg) {
951 		case MTD_FILE_MODE_OTP_FACTORY:
952 		case MTD_FILE_MODE_OTP_USER:
953 			ret = otp_select_filemode(mfi, arg);
954 			break;
955 
956 		case MTD_FILE_MODE_RAW:
957 			if (!mtd_has_oob(mtd))
958 				return -EOPNOTSUPP;
959 			mfi->mode = arg;
960 
961 		case MTD_FILE_MODE_NORMAL:
962 			break;
963 		default:
964 			ret = -EINVAL;
965 		}
966 		file->f_pos = 0;
967 		break;
968 	}
969 
970 	case BLKPG:
971 	{
972 		struct blkpg_ioctl_arg __user *blk_arg = argp;
973 		struct blkpg_ioctl_arg a;
974 
975 		if (copy_from_user(&a, blk_arg, sizeof(a)))
976 			ret = -EFAULT;
977 		else
978 			ret = mtdchar_blkpg_ioctl(mtd, &a);
979 		break;
980 	}
981 
982 	case BLKRRPART:
983 	{
984 		/* No reread partition feature. Just return ok */
985 		ret = 0;
986 		break;
987 	}
988 
989 	default:
990 		ret = -ENOTTY;
991 	}
992 
993 	return ret;
994 } /* memory_ioctl */
995 
996 static long mtdchar_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
997 {
998 	int ret;
999 
1000 	mutex_lock(&mtd_mutex);
1001 	ret = mtdchar_ioctl(file, cmd, arg);
1002 	mutex_unlock(&mtd_mutex);
1003 
1004 	return ret;
1005 }
1006 
1007 #ifdef CONFIG_COMPAT
1008 
1009 struct mtd_oob_buf32 {
1010 	u_int32_t start;
1011 	u_int32_t length;
1012 	compat_caddr_t ptr;	/* unsigned char* */
1013 };
1014 
1015 #define MEMWRITEOOB32		_IOWR('M', 3, struct mtd_oob_buf32)
1016 #define MEMREADOOB32		_IOWR('M', 4, struct mtd_oob_buf32)
1017 
1018 static long mtdchar_compat_ioctl(struct file *file, unsigned int cmd,
1019 	unsigned long arg)
1020 {
1021 	struct mtd_file_info *mfi = file->private_data;
1022 	struct mtd_info *mtd = mfi->mtd;
1023 	void __user *argp = compat_ptr(arg);
1024 	int ret = 0;
1025 
1026 	mutex_lock(&mtd_mutex);
1027 
1028 	switch (cmd) {
1029 	case MEMWRITEOOB32:
1030 	{
1031 		struct mtd_oob_buf32 buf;
1032 		struct mtd_oob_buf32 __user *buf_user = argp;
1033 
1034 		if (copy_from_user(&buf, argp, sizeof(buf)))
1035 			ret = -EFAULT;
1036 		else
1037 			ret = mtdchar_writeoob(file, mtd, buf.start,
1038 				buf.length, compat_ptr(buf.ptr),
1039 				&buf_user->length);
1040 		break;
1041 	}
1042 
1043 	case MEMREADOOB32:
1044 	{
1045 		struct mtd_oob_buf32 buf;
1046 		struct mtd_oob_buf32 __user *buf_user = argp;
1047 
1048 		/* NOTE: writes return length to buf->start */
1049 		if (copy_from_user(&buf, argp, sizeof(buf)))
1050 			ret = -EFAULT;
1051 		else
1052 			ret = mtdchar_readoob(file, mtd, buf.start,
1053 				buf.length, compat_ptr(buf.ptr),
1054 				&buf_user->start);
1055 		break;
1056 	}
1057 
1058 	case BLKPG:
1059 	{
1060 		/* Convert from blkpg_compat_ioctl_arg to blkpg_ioctl_arg */
1061 		struct blkpg_compat_ioctl_arg __user *uarg = argp;
1062 		struct blkpg_compat_ioctl_arg compat_arg;
1063 		struct blkpg_ioctl_arg a;
1064 
1065 		if (copy_from_user(&compat_arg, uarg, sizeof(compat_arg))) {
1066 			ret = -EFAULT;
1067 			break;
1068 		}
1069 
1070 		memset(&a, 0, sizeof(a));
1071 		a.op = compat_arg.op;
1072 		a.flags = compat_arg.flags;
1073 		a.datalen = compat_arg.datalen;
1074 		a.data = compat_ptr(compat_arg.data);
1075 
1076 		ret = mtdchar_blkpg_ioctl(mtd, &a);
1077 		break;
1078 	}
1079 
1080 	default:
1081 		ret = mtdchar_ioctl(file, cmd, (unsigned long)argp);
1082 	}
1083 
1084 	mutex_unlock(&mtd_mutex);
1085 
1086 	return ret;
1087 }
1088 
1089 #endif /* CONFIG_COMPAT */
1090 
1091 /*
1092  * try to determine where a shared mapping can be made
1093  * - only supported for NOMMU at the moment (MMU can't doesn't copy private
1094  *   mappings)
1095  */
1096 #ifndef CONFIG_MMU
1097 static unsigned long mtdchar_get_unmapped_area(struct file *file,
1098 					   unsigned long addr,
1099 					   unsigned long len,
1100 					   unsigned long pgoff,
1101 					   unsigned long flags)
1102 {
1103 	struct mtd_file_info *mfi = file->private_data;
1104 	struct mtd_info *mtd = mfi->mtd;
1105 	unsigned long offset;
1106 	int ret;
1107 
1108 	if (addr != 0)
1109 		return (unsigned long) -EINVAL;
1110 
1111 	if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT))
1112 		return (unsigned long) -EINVAL;
1113 
1114 	offset = pgoff << PAGE_SHIFT;
1115 	if (offset > mtd->size - len)
1116 		return (unsigned long) -EINVAL;
1117 
1118 	ret = mtd_get_unmapped_area(mtd, len, offset, flags);
1119 	return ret == -EOPNOTSUPP ? -ENODEV : ret;
1120 }
1121 
1122 static unsigned mtdchar_mmap_capabilities(struct file *file)
1123 {
1124 	struct mtd_file_info *mfi = file->private_data;
1125 
1126 	return mtd_mmap_capabilities(mfi->mtd);
1127 }
1128 #endif
1129 
1130 /*
1131  * set up a mapping for shared memory segments
1132  */
1133 static int mtdchar_mmap(struct file *file, struct vm_area_struct *vma)
1134 {
1135 #ifdef CONFIG_MMU
1136 	struct mtd_file_info *mfi = file->private_data;
1137 	struct mtd_info *mtd = mfi->mtd;
1138 	struct map_info *map = mtd->priv;
1139 
1140         /* This is broken because it assumes the MTD device is map-based
1141 	   and that mtd->priv is a valid struct map_info.  It should be
1142 	   replaced with something that uses the mtd_get_unmapped_area()
1143 	   operation properly. */
1144 	if (0 /*mtd->type == MTD_RAM || mtd->type == MTD_ROM*/) {
1145 #ifdef pgprot_noncached
1146 		if (file->f_flags & O_DSYNC || map->phys >= __pa(high_memory))
1147 			vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1148 #endif
1149 		return vm_iomap_memory(vma, map->phys, map->size);
1150 	}
1151 	return -ENODEV;
1152 #else
1153 	return vma->vm_flags & VM_SHARED ? 0 : -EACCES;
1154 #endif
1155 }
1156 
1157 static const struct file_operations mtd_fops = {
1158 	.owner		= THIS_MODULE,
1159 	.llseek		= mtdchar_lseek,
1160 	.read		= mtdchar_read,
1161 	.write		= mtdchar_write,
1162 	.unlocked_ioctl	= mtdchar_unlocked_ioctl,
1163 #ifdef CONFIG_COMPAT
1164 	.compat_ioctl	= mtdchar_compat_ioctl,
1165 #endif
1166 	.open		= mtdchar_open,
1167 	.release	= mtdchar_close,
1168 	.mmap		= mtdchar_mmap,
1169 #ifndef CONFIG_MMU
1170 	.get_unmapped_area = mtdchar_get_unmapped_area,
1171 	.mmap_capabilities = mtdchar_mmap_capabilities,
1172 #endif
1173 };
1174 
1175 int __init init_mtdchar(void)
1176 {
1177 	int ret;
1178 
1179 	ret = __register_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS,
1180 				   "mtd", &mtd_fops);
1181 	if (ret < 0) {
1182 		pr_err("Can't allocate major number %d for MTD\n",
1183 		       MTD_CHAR_MAJOR);
1184 		return ret;
1185 	}
1186 
1187 	return ret;
1188 }
1189 
1190 void __exit cleanup_mtdchar(void)
1191 {
1192 	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1193 }
1194 
1195 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);
1196