xref: /linux/drivers/mtd/mtdchar.c (revision c0e79fd89749b0cda1c72049e2772dd2eeada86f)
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_file_info *mfi = file->private_data;
353 	struct mtd_oob_ops ops = {};
354 	uint32_t retlen;
355 	int ret = 0;
356 
357 	if (!(file->f_mode & FMODE_WRITE))
358 		return -EPERM;
359 
360 	if (length > 4096)
361 		return -EINVAL;
362 
363 	if (!mtd->_write_oob)
364 		return -EOPNOTSUPP;
365 
366 	ops.ooblen = length;
367 	ops.ooboffs = start & (mtd->writesize - 1);
368 	ops.datbuf = NULL;
369 	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
370 		MTD_OPS_PLACE_OOB;
371 
372 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
373 		return -EINVAL;
374 
375 	ops.oobbuf = memdup_user(ptr, length);
376 	if (IS_ERR(ops.oobbuf))
377 		return PTR_ERR(ops.oobbuf);
378 
379 	start &= ~((uint64_t)mtd->writesize - 1);
380 	ret = mtd_write_oob(mtd, start, &ops);
381 
382 	if (ops.oobretlen > 0xFFFFFFFFU)
383 		ret = -EOVERFLOW;
384 	retlen = ops.oobretlen;
385 	if (copy_to_user(retp, &retlen, sizeof(length)))
386 		ret = -EFAULT;
387 
388 	kfree(ops.oobbuf);
389 	return ret;
390 }
391 
392 static int mtdchar_readoob(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_file_info *mfi = file->private_data;
397 	struct mtd_oob_ops ops = {};
398 	int ret = 0;
399 
400 	if (length > 4096)
401 		return -EINVAL;
402 
403 	ops.ooblen = length;
404 	ops.ooboffs = start & (mtd->writesize - 1);
405 	ops.datbuf = NULL;
406 	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
407 		MTD_OPS_PLACE_OOB;
408 
409 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
410 		return -EINVAL;
411 
412 	ops.oobbuf = kmalloc(length, GFP_KERNEL);
413 	if (!ops.oobbuf)
414 		return -ENOMEM;
415 
416 	start &= ~((uint64_t)mtd->writesize - 1);
417 	ret = mtd_read_oob(mtd, start, &ops);
418 
419 	if (put_user(ops.oobretlen, retp))
420 		ret = -EFAULT;
421 	else if (ops.oobretlen && copy_to_user(ptr, ops.oobbuf,
422 					    ops.oobretlen))
423 		ret = -EFAULT;
424 
425 	kfree(ops.oobbuf);
426 
427 	/*
428 	 * NAND returns -EBADMSG on ECC errors, but it returns the OOB
429 	 * data. For our userspace tools it is important to dump areas
430 	 * with ECC errors!
431 	 * For kernel internal usage it also might return -EUCLEAN
432 	 * to signal the caller that a bitflip has occurred and has
433 	 * been corrected by the ECC algorithm.
434 	 *
435 	 * Note: currently the standard NAND function, nand_read_oob_std,
436 	 * does not calculate ECC for the OOB area, so do not rely on
437 	 * this behavior unless you have replaced it with your own.
438 	 */
439 	if (mtd_is_bitflip_or_eccerr(ret))
440 		return 0;
441 
442 	return ret;
443 }
444 
445 /*
446  * Copies (and truncates, if necessary) OOB layout information to the
447  * deprecated layout struct, nand_ecclayout_user. This is necessary only to
448  * support the deprecated API ioctl ECCGETLAYOUT while allowing all new
449  * functionality to use mtd_ooblayout_ops flexibly (i.e. mtd_ooblayout_ops
450  * can describe any kind of OOB layout with almost zero overhead from a
451  * memory usage point of view).
452  */
453 static int shrink_ecclayout(struct mtd_info *mtd,
454 			    struct nand_ecclayout_user *to)
455 {
456 	struct mtd_oob_region oobregion;
457 	int i, section = 0, ret;
458 
459 	if (!mtd || !to)
460 		return -EINVAL;
461 
462 	memset(to, 0, sizeof(*to));
463 
464 	to->eccbytes = 0;
465 	for (i = 0; i < MTD_MAX_ECCPOS_ENTRIES;) {
466 		u32 eccpos;
467 
468 		ret = mtd_ooblayout_ecc(mtd, section++, &oobregion);
469 		if (ret < 0) {
470 			if (ret != -ERANGE)
471 				return ret;
472 
473 			break;
474 		}
475 
476 		eccpos = oobregion.offset;
477 		for (; i < MTD_MAX_ECCPOS_ENTRIES &&
478 		       eccpos < oobregion.offset + oobregion.length; i++) {
479 			to->eccpos[i] = eccpos++;
480 			to->eccbytes++;
481 		}
482 	}
483 
484 	for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES; i++) {
485 		ret = mtd_ooblayout_free(mtd, i, &oobregion);
486 		if (ret < 0) {
487 			if (ret != -ERANGE)
488 				return ret;
489 
490 			break;
491 		}
492 
493 		to->oobfree[i].offset = oobregion.offset;
494 		to->oobfree[i].length = oobregion.length;
495 		to->oobavail += to->oobfree[i].length;
496 	}
497 
498 	return 0;
499 }
500 
501 static int get_oobinfo(struct mtd_info *mtd, struct nand_oobinfo *to)
502 {
503 	struct mtd_oob_region oobregion;
504 	int i, section = 0, ret;
505 
506 	if (!mtd || !to)
507 		return -EINVAL;
508 
509 	memset(to, 0, sizeof(*to));
510 
511 	to->eccbytes = 0;
512 	for (i = 0; i < ARRAY_SIZE(to->eccpos);) {
513 		u32 eccpos;
514 
515 		ret = mtd_ooblayout_ecc(mtd, section++, &oobregion);
516 		if (ret < 0) {
517 			if (ret != -ERANGE)
518 				return ret;
519 
520 			break;
521 		}
522 
523 		if (oobregion.length + i > ARRAY_SIZE(to->eccpos))
524 			return -EINVAL;
525 
526 		eccpos = oobregion.offset;
527 		for (; eccpos < oobregion.offset + oobregion.length; i++) {
528 			to->eccpos[i] = eccpos++;
529 			to->eccbytes++;
530 		}
531 	}
532 
533 	for (i = 0; i < 8; i++) {
534 		ret = mtd_ooblayout_free(mtd, i, &oobregion);
535 		if (ret < 0) {
536 			if (ret != -ERANGE)
537 				return ret;
538 
539 			break;
540 		}
541 
542 		to->oobfree[i][0] = oobregion.offset;
543 		to->oobfree[i][1] = oobregion.length;
544 	}
545 
546 	to->useecc = MTD_NANDECC_AUTOPLACE;
547 
548 	return 0;
549 }
550 
551 static int mtdchar_blkpg_ioctl(struct mtd_info *mtd,
552 			       struct blkpg_ioctl_arg *arg)
553 {
554 	struct blkpg_partition p;
555 
556 	if (!capable(CAP_SYS_ADMIN))
557 		return -EPERM;
558 
559 	if (copy_from_user(&p, arg->data, sizeof(p)))
560 		return -EFAULT;
561 
562 	switch (arg->op) {
563 	case BLKPG_ADD_PARTITION:
564 
565 		/* Only master mtd device must be used to add partitions */
566 		if (mtd_is_partition(mtd))
567 			return -EINVAL;
568 
569 		/* Sanitize user input */
570 		p.devname[BLKPG_DEVNAMELTH - 1] = '\0';
571 
572 		return mtd_add_partition(mtd, p.devname, p.start, p.length);
573 
574 	case BLKPG_DEL_PARTITION:
575 
576 		if (p.pno < 0)
577 			return -EINVAL;
578 
579 		return mtd_del_partition(mtd, p.pno);
580 
581 	default:
582 		return -EINVAL;
583 	}
584 }
585 
586 static int mtdchar_write_ioctl(struct mtd_info *mtd,
587 		struct mtd_write_req __user *argp)
588 {
589 	struct mtd_write_req req;
590 	struct mtd_oob_ops ops = {};
591 	const void __user *usr_data, *usr_oob;
592 	int ret;
593 
594 	if (copy_from_user(&req, argp, sizeof(req)))
595 		return -EFAULT;
596 
597 	usr_data = (const void __user *)(uintptr_t)req.usr_data;
598 	usr_oob = (const void __user *)(uintptr_t)req.usr_oob;
599 
600 	if (!mtd->_write_oob)
601 		return -EOPNOTSUPP;
602 
603 	ops.mode = req.mode;
604 	ops.len = (size_t)req.len;
605 	ops.ooblen = (size_t)req.ooblen;
606 	ops.ooboffs = 0;
607 
608 	if (usr_data) {
609 		ops.datbuf = memdup_user(usr_data, ops.len);
610 		if (IS_ERR(ops.datbuf))
611 			return PTR_ERR(ops.datbuf);
612 	} else {
613 		ops.datbuf = NULL;
614 	}
615 
616 	if (usr_oob) {
617 		ops.oobbuf = memdup_user(usr_oob, ops.ooblen);
618 		if (IS_ERR(ops.oobbuf)) {
619 			kfree(ops.datbuf);
620 			return PTR_ERR(ops.oobbuf);
621 		}
622 	} else {
623 		ops.oobbuf = NULL;
624 	}
625 
626 	ret = mtd_write_oob(mtd, (loff_t)req.start, &ops);
627 
628 	kfree(ops.datbuf);
629 	kfree(ops.oobbuf);
630 
631 	return ret;
632 }
633 
634 static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg)
635 {
636 	struct mtd_file_info *mfi = file->private_data;
637 	struct mtd_info *mtd = mfi->mtd;
638 	void __user *argp = (void __user *)arg;
639 	int ret = 0;
640 	struct mtd_info_user info;
641 
642 	pr_debug("MTD_ioctl\n");
643 
644 	switch (cmd) {
645 	case MEMGETREGIONCOUNT:
646 		if (copy_to_user(argp, &(mtd->numeraseregions), sizeof(int)))
647 			return -EFAULT;
648 		break;
649 
650 	case MEMGETREGIONINFO:
651 	{
652 		uint32_t ur_idx;
653 		struct mtd_erase_region_info *kr;
654 		struct region_info_user __user *ur = argp;
655 
656 		if (get_user(ur_idx, &(ur->regionindex)))
657 			return -EFAULT;
658 
659 		if (ur_idx >= mtd->numeraseregions)
660 			return -EINVAL;
661 
662 		kr = &(mtd->eraseregions[ur_idx]);
663 
664 		if (put_user(kr->offset, &(ur->offset))
665 		    || put_user(kr->erasesize, &(ur->erasesize))
666 		    || put_user(kr->numblocks, &(ur->numblocks)))
667 			return -EFAULT;
668 
669 		break;
670 	}
671 
672 	case MEMGETINFO:
673 		memset(&info, 0, sizeof(info));
674 		info.type	= mtd->type;
675 		info.flags	= mtd->flags;
676 		info.size	= mtd->size;
677 		info.erasesize	= mtd->erasesize;
678 		info.writesize	= mtd->writesize;
679 		info.oobsize	= mtd->oobsize;
680 		/* The below field is obsolete */
681 		info.padding	= 0;
682 		if (copy_to_user(argp, &info, sizeof(struct mtd_info_user)))
683 			return -EFAULT;
684 		break;
685 
686 	case MEMERASE:
687 	case MEMERASE64:
688 	{
689 		struct erase_info *erase;
690 
691 		if(!(file->f_mode & FMODE_WRITE))
692 			return -EPERM;
693 
694 		erase=kzalloc(sizeof(struct erase_info),GFP_KERNEL);
695 		if (!erase)
696 			ret = -ENOMEM;
697 		else {
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 
720 			ret = mtd_erase(mtd, erase);
721 			kfree(erase);
722 		}
723 		break;
724 	}
725 
726 	case MEMWRITEOOB:
727 	{
728 		struct mtd_oob_buf buf;
729 		struct mtd_oob_buf __user *buf_user = argp;
730 
731 		/* NOTE: writes return length to buf_user->length */
732 		if (copy_from_user(&buf, argp, sizeof(buf)))
733 			ret = -EFAULT;
734 		else
735 			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
736 				buf.ptr, &buf_user->length);
737 		break;
738 	}
739 
740 	case MEMREADOOB:
741 	{
742 		struct mtd_oob_buf buf;
743 		struct mtd_oob_buf __user *buf_user = argp;
744 
745 		/* NOTE: writes return length to buf_user->start */
746 		if (copy_from_user(&buf, argp, sizeof(buf)))
747 			ret = -EFAULT;
748 		else
749 			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
750 				buf.ptr, &buf_user->start);
751 		break;
752 	}
753 
754 	case MEMWRITEOOB64:
755 	{
756 		struct mtd_oob_buf64 buf;
757 		struct mtd_oob_buf64 __user *buf_user = argp;
758 
759 		if (copy_from_user(&buf, argp, sizeof(buf)))
760 			ret = -EFAULT;
761 		else
762 			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
763 				(void __user *)(uintptr_t)buf.usr_ptr,
764 				&buf_user->length);
765 		break;
766 	}
767 
768 	case MEMREADOOB64:
769 	{
770 		struct mtd_oob_buf64 buf;
771 		struct mtd_oob_buf64 __user *buf_user = argp;
772 
773 		if (copy_from_user(&buf, argp, sizeof(buf)))
774 			ret = -EFAULT;
775 		else
776 			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
777 				(void __user *)(uintptr_t)buf.usr_ptr,
778 				&buf_user->length);
779 		break;
780 	}
781 
782 	case MEMWRITE:
783 	{
784 		ret = mtdchar_write_ioctl(mtd,
785 		      (struct mtd_write_req __user *)arg);
786 		break;
787 	}
788 
789 	case MEMLOCK:
790 	{
791 		struct erase_info_user einfo;
792 
793 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
794 			return -EFAULT;
795 
796 		ret = mtd_lock(mtd, einfo.start, einfo.length);
797 		break;
798 	}
799 
800 	case MEMUNLOCK:
801 	{
802 		struct erase_info_user einfo;
803 
804 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
805 			return -EFAULT;
806 
807 		ret = mtd_unlock(mtd, einfo.start, einfo.length);
808 		break;
809 	}
810 
811 	case MEMISLOCKED:
812 	{
813 		struct erase_info_user einfo;
814 
815 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
816 			return -EFAULT;
817 
818 		ret = mtd_is_locked(mtd, einfo.start, einfo.length);
819 		break;
820 	}
821 
822 	/* Legacy interface */
823 	case MEMGETOOBSEL:
824 	{
825 		struct nand_oobinfo oi;
826 
827 		if (!mtd->ooblayout)
828 			return -EOPNOTSUPP;
829 
830 		ret = get_oobinfo(mtd, &oi);
831 		if (ret)
832 			return ret;
833 
834 		if (copy_to_user(argp, &oi, sizeof(struct nand_oobinfo)))
835 			return -EFAULT;
836 		break;
837 	}
838 
839 	case MEMGETBADBLOCK:
840 	{
841 		loff_t offs;
842 
843 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
844 			return -EFAULT;
845 		return mtd_block_isbad(mtd, offs);
846 		break;
847 	}
848 
849 	case MEMSETBADBLOCK:
850 	{
851 		loff_t offs;
852 
853 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
854 			return -EFAULT;
855 		return mtd_block_markbad(mtd, offs);
856 		break;
857 	}
858 
859 	case OTPSELECT:
860 	{
861 		int mode;
862 		if (copy_from_user(&mode, argp, sizeof(int)))
863 			return -EFAULT;
864 
865 		mfi->mode = MTD_FILE_MODE_NORMAL;
866 
867 		ret = otp_select_filemode(mfi, mode);
868 
869 		file->f_pos = 0;
870 		break;
871 	}
872 
873 	case OTPGETREGIONCOUNT:
874 	case OTPGETREGIONINFO:
875 	{
876 		struct otp_info *buf = kmalloc(4096, GFP_KERNEL);
877 		size_t retlen;
878 		if (!buf)
879 			return -ENOMEM;
880 		switch (mfi->mode) {
881 		case MTD_FILE_MODE_OTP_FACTORY:
882 			ret = mtd_get_fact_prot_info(mtd, 4096, &retlen, buf);
883 			break;
884 		case MTD_FILE_MODE_OTP_USER:
885 			ret = mtd_get_user_prot_info(mtd, 4096, &retlen, buf);
886 			break;
887 		default:
888 			ret = -EINVAL;
889 			break;
890 		}
891 		if (!ret) {
892 			if (cmd == OTPGETREGIONCOUNT) {
893 				int nbr = retlen / sizeof(struct otp_info);
894 				ret = copy_to_user(argp, &nbr, sizeof(int));
895 			} else
896 				ret = copy_to_user(argp, buf, retlen);
897 			if (ret)
898 				ret = -EFAULT;
899 		}
900 		kfree(buf);
901 		break;
902 	}
903 
904 	case OTPLOCK:
905 	{
906 		struct otp_info oinfo;
907 
908 		if (mfi->mode != MTD_FILE_MODE_OTP_USER)
909 			return -EINVAL;
910 		if (copy_from_user(&oinfo, argp, sizeof(oinfo)))
911 			return -EFAULT;
912 		ret = mtd_lock_user_prot_reg(mtd, oinfo.start, oinfo.length);
913 		break;
914 	}
915 
916 	/* This ioctl is being deprecated - it truncates the ECC layout */
917 	case ECCGETLAYOUT:
918 	{
919 		struct nand_ecclayout_user *usrlay;
920 
921 		if (!mtd->ooblayout)
922 			return -EOPNOTSUPP;
923 
924 		usrlay = kmalloc(sizeof(*usrlay), GFP_KERNEL);
925 		if (!usrlay)
926 			return -ENOMEM;
927 
928 		shrink_ecclayout(mtd, usrlay);
929 
930 		if (copy_to_user(argp, usrlay, sizeof(*usrlay)))
931 			ret = -EFAULT;
932 		kfree(usrlay);
933 		break;
934 	}
935 
936 	case ECCGETSTATS:
937 	{
938 		if (copy_to_user(argp, &mtd->ecc_stats,
939 				 sizeof(struct mtd_ecc_stats)))
940 			return -EFAULT;
941 		break;
942 	}
943 
944 	case MTDFILEMODE:
945 	{
946 		mfi->mode = 0;
947 
948 		switch(arg) {
949 		case MTD_FILE_MODE_OTP_FACTORY:
950 		case MTD_FILE_MODE_OTP_USER:
951 			ret = otp_select_filemode(mfi, arg);
952 			break;
953 
954 		case MTD_FILE_MODE_RAW:
955 			if (!mtd_has_oob(mtd))
956 				return -EOPNOTSUPP;
957 			mfi->mode = arg;
958 
959 		case MTD_FILE_MODE_NORMAL:
960 			break;
961 		default:
962 			ret = -EINVAL;
963 		}
964 		file->f_pos = 0;
965 		break;
966 	}
967 
968 	case BLKPG:
969 	{
970 		struct blkpg_ioctl_arg __user *blk_arg = argp;
971 		struct blkpg_ioctl_arg a;
972 
973 		if (copy_from_user(&a, blk_arg, sizeof(a)))
974 			ret = -EFAULT;
975 		else
976 			ret = mtdchar_blkpg_ioctl(mtd, &a);
977 		break;
978 	}
979 
980 	case BLKRRPART:
981 	{
982 		/* No reread partition feature. Just return ok */
983 		ret = 0;
984 		break;
985 	}
986 
987 	default:
988 		ret = -ENOTTY;
989 	}
990 
991 	return ret;
992 } /* memory_ioctl */
993 
994 static long mtdchar_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
995 {
996 	int ret;
997 
998 	mutex_lock(&mtd_mutex);
999 	ret = mtdchar_ioctl(file, cmd, arg);
1000 	mutex_unlock(&mtd_mutex);
1001 
1002 	return ret;
1003 }
1004 
1005 #ifdef CONFIG_COMPAT
1006 
1007 struct mtd_oob_buf32 {
1008 	u_int32_t start;
1009 	u_int32_t length;
1010 	compat_caddr_t ptr;	/* unsigned char* */
1011 };
1012 
1013 #define MEMWRITEOOB32		_IOWR('M', 3, struct mtd_oob_buf32)
1014 #define MEMREADOOB32		_IOWR('M', 4, struct mtd_oob_buf32)
1015 
1016 static long mtdchar_compat_ioctl(struct file *file, unsigned int cmd,
1017 	unsigned long arg)
1018 {
1019 	struct mtd_file_info *mfi = file->private_data;
1020 	struct mtd_info *mtd = mfi->mtd;
1021 	void __user *argp = compat_ptr(arg);
1022 	int ret = 0;
1023 
1024 	mutex_lock(&mtd_mutex);
1025 
1026 	switch (cmd) {
1027 	case MEMWRITEOOB32:
1028 	{
1029 		struct mtd_oob_buf32 buf;
1030 		struct mtd_oob_buf32 __user *buf_user = argp;
1031 
1032 		if (copy_from_user(&buf, argp, sizeof(buf)))
1033 			ret = -EFAULT;
1034 		else
1035 			ret = mtdchar_writeoob(file, mtd, buf.start,
1036 				buf.length, compat_ptr(buf.ptr),
1037 				&buf_user->length);
1038 		break;
1039 	}
1040 
1041 	case MEMREADOOB32:
1042 	{
1043 		struct mtd_oob_buf32 buf;
1044 		struct mtd_oob_buf32 __user *buf_user = argp;
1045 
1046 		/* NOTE: writes return length to buf->start */
1047 		if (copy_from_user(&buf, argp, sizeof(buf)))
1048 			ret = -EFAULT;
1049 		else
1050 			ret = mtdchar_readoob(file, mtd, buf.start,
1051 				buf.length, compat_ptr(buf.ptr),
1052 				&buf_user->start);
1053 		break;
1054 	}
1055 
1056 	case BLKPG:
1057 	{
1058 		/* Convert from blkpg_compat_ioctl_arg to blkpg_ioctl_arg */
1059 		struct blkpg_compat_ioctl_arg __user *uarg = argp;
1060 		struct blkpg_compat_ioctl_arg compat_arg;
1061 		struct blkpg_ioctl_arg a;
1062 
1063 		if (copy_from_user(&compat_arg, uarg, sizeof(compat_arg))) {
1064 			ret = -EFAULT;
1065 			break;
1066 		}
1067 
1068 		memset(&a, 0, sizeof(a));
1069 		a.op = compat_arg.op;
1070 		a.flags = compat_arg.flags;
1071 		a.datalen = compat_arg.datalen;
1072 		a.data = compat_ptr(compat_arg.data);
1073 
1074 		ret = mtdchar_blkpg_ioctl(mtd, &a);
1075 		break;
1076 	}
1077 
1078 	default:
1079 		ret = mtdchar_ioctl(file, cmd, (unsigned long)argp);
1080 	}
1081 
1082 	mutex_unlock(&mtd_mutex);
1083 
1084 	return ret;
1085 }
1086 
1087 #endif /* CONFIG_COMPAT */
1088 
1089 /*
1090  * try to determine where a shared mapping can be made
1091  * - only supported for NOMMU at the moment (MMU can't doesn't copy private
1092  *   mappings)
1093  */
1094 #ifndef CONFIG_MMU
1095 static unsigned long mtdchar_get_unmapped_area(struct file *file,
1096 					   unsigned long addr,
1097 					   unsigned long len,
1098 					   unsigned long pgoff,
1099 					   unsigned long flags)
1100 {
1101 	struct mtd_file_info *mfi = file->private_data;
1102 	struct mtd_info *mtd = mfi->mtd;
1103 	unsigned long offset;
1104 	int ret;
1105 
1106 	if (addr != 0)
1107 		return (unsigned long) -EINVAL;
1108 
1109 	if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT))
1110 		return (unsigned long) -EINVAL;
1111 
1112 	offset = pgoff << PAGE_SHIFT;
1113 	if (offset > mtd->size - len)
1114 		return (unsigned long) -EINVAL;
1115 
1116 	ret = mtd_get_unmapped_area(mtd, len, offset, flags);
1117 	return ret == -EOPNOTSUPP ? -ENODEV : ret;
1118 }
1119 
1120 static unsigned mtdchar_mmap_capabilities(struct file *file)
1121 {
1122 	struct mtd_file_info *mfi = file->private_data;
1123 
1124 	return mtd_mmap_capabilities(mfi->mtd);
1125 }
1126 #endif
1127 
1128 /*
1129  * set up a mapping for shared memory segments
1130  */
1131 static int mtdchar_mmap(struct file *file, struct vm_area_struct *vma)
1132 {
1133 #ifdef CONFIG_MMU
1134 	struct mtd_file_info *mfi = file->private_data;
1135 	struct mtd_info *mtd = mfi->mtd;
1136 	struct map_info *map = mtd->priv;
1137 
1138         /* This is broken because it assumes the MTD device is map-based
1139 	   and that mtd->priv is a valid struct map_info.  It should be
1140 	   replaced with something that uses the mtd_get_unmapped_area()
1141 	   operation properly. */
1142 	if (0 /*mtd->type == MTD_RAM || mtd->type == MTD_ROM*/) {
1143 #ifdef pgprot_noncached
1144 		if (file->f_flags & O_DSYNC || map->phys >= __pa(high_memory))
1145 			vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1146 #endif
1147 		return vm_iomap_memory(vma, map->phys, map->size);
1148 	}
1149 	return -ENODEV;
1150 #else
1151 	return vma->vm_flags & VM_SHARED ? 0 : -EACCES;
1152 #endif
1153 }
1154 
1155 static const struct file_operations mtd_fops = {
1156 	.owner		= THIS_MODULE,
1157 	.llseek		= mtdchar_lseek,
1158 	.read		= mtdchar_read,
1159 	.write		= mtdchar_write,
1160 	.unlocked_ioctl	= mtdchar_unlocked_ioctl,
1161 #ifdef CONFIG_COMPAT
1162 	.compat_ioctl	= mtdchar_compat_ioctl,
1163 #endif
1164 	.open		= mtdchar_open,
1165 	.release	= mtdchar_close,
1166 	.mmap		= mtdchar_mmap,
1167 #ifndef CONFIG_MMU
1168 	.get_unmapped_area = mtdchar_get_unmapped_area,
1169 	.mmap_capabilities = mtdchar_mmap_capabilities,
1170 #endif
1171 };
1172 
1173 int __init init_mtdchar(void)
1174 {
1175 	int ret;
1176 
1177 	ret = __register_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS,
1178 				   "mtd", &mtd_fops);
1179 	if (ret < 0) {
1180 		pr_err("Can't allocate major number %d for MTD\n",
1181 		       MTD_CHAR_MAJOR);
1182 		return ret;
1183 	}
1184 
1185 	return ret;
1186 }
1187 
1188 void __exit cleanup_mtdchar(void)
1189 {
1190 	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1191 }
1192 
1193 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);
1194