xref: /linux/drivers/mtd/mtdchar.c (revision 3c4fc7bf4c9e66fe71abcbf93f62f4ddb89b7f15)
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 /*
31  * Data structure to hold the pointer to the mtd device as well
32  * as mode information of various use cases.
33  */
34 struct mtd_file_info {
35 	struct mtd_info *mtd;
36 	enum mtd_file_modes mode;
37 };
38 
39 static loff_t mtdchar_lseek(struct file *file, loff_t offset, int orig)
40 {
41 	struct mtd_file_info *mfi = file->private_data;
42 	return fixed_size_llseek(file, offset, orig, mfi->mtd->size);
43 }
44 
45 static int mtdchar_open(struct inode *inode, struct file *file)
46 {
47 	int minor = iminor(inode);
48 	int devnum = minor >> 1;
49 	int ret = 0;
50 	struct mtd_info *mtd;
51 	struct mtd_file_info *mfi;
52 
53 	pr_debug("MTD_open\n");
54 
55 	/* You can't open the RO devices RW */
56 	if ((file->f_mode & FMODE_WRITE) && (minor & 1))
57 		return -EACCES;
58 
59 	mtd = get_mtd_device(NULL, devnum);
60 
61 	if (IS_ERR(mtd))
62 		return PTR_ERR(mtd);
63 
64 	if (mtd->type == MTD_ABSENT) {
65 		ret = -ENODEV;
66 		goto out1;
67 	}
68 
69 	/* You can't open it RW if it's not a writeable device */
70 	if ((file->f_mode & FMODE_WRITE) && !(mtd->flags & MTD_WRITEABLE)) {
71 		ret = -EACCES;
72 		goto out1;
73 	}
74 
75 	mfi = kzalloc(sizeof(*mfi), GFP_KERNEL);
76 	if (!mfi) {
77 		ret = -ENOMEM;
78 		goto out1;
79 	}
80 	mfi->mtd = mtd;
81 	file->private_data = mfi;
82 	return 0;
83 
84 out1:
85 	put_mtd_device(mtd);
86 	return ret;
87 } /* mtdchar_open */
88 
89 /*====================================================================*/
90 
91 static int mtdchar_close(struct inode *inode, struct file *file)
92 {
93 	struct mtd_file_info *mfi = file->private_data;
94 	struct mtd_info *mtd = mfi->mtd;
95 
96 	pr_debug("MTD_close\n");
97 
98 	/* Only sync if opened RW */
99 	if ((file->f_mode & FMODE_WRITE))
100 		mtd_sync(mtd);
101 
102 	put_mtd_device(mtd);
103 	file->private_data = NULL;
104 	kfree(mfi);
105 
106 	return 0;
107 } /* mtdchar_close */
108 
109 /* Back in June 2001, dwmw2 wrote:
110  *
111  *   FIXME: This _really_ needs to die. In 2.5, we should lock the
112  *   userspace buffer down and use it directly with readv/writev.
113  *
114  * The implementation below, using mtd_kmalloc_up_to, mitigates
115  * allocation failures when the system is under low-memory situations
116  * or if memory is highly fragmented at the cost of reducing the
117  * performance of the requested transfer due to a smaller buffer size.
118  *
119  * A more complex but more memory-efficient implementation based on
120  * get_user_pages and iovecs to cover extents of those pages is a
121  * longer-term goal, as intimated by dwmw2 above. However, for the
122  * write case, this requires yet more complex head and tail transfer
123  * handling when those head and tail offsets and sizes are such that
124  * alignment requirements are not met in the NAND subdriver.
125  */
126 
127 static ssize_t mtdchar_read(struct file *file, char __user *buf, size_t count,
128 			loff_t *ppos)
129 {
130 	struct mtd_file_info *mfi = file->private_data;
131 	struct mtd_info *mtd = mfi->mtd;
132 	size_t retlen;
133 	size_t total_retlen=0;
134 	int ret=0;
135 	int len;
136 	size_t size = count;
137 	char *kbuf;
138 
139 	pr_debug("MTD_read\n");
140 
141 	if (*ppos + count > mtd->size) {
142 		if (*ppos < mtd->size)
143 			count = mtd->size - *ppos;
144 		else
145 			count = 0;
146 	}
147 
148 	if (!count)
149 		return 0;
150 
151 	kbuf = mtd_kmalloc_up_to(mtd, &size);
152 	if (!kbuf)
153 		return -ENOMEM;
154 
155 	while (count) {
156 		len = min_t(size_t, count, size);
157 
158 		switch (mfi->mode) {
159 		case MTD_FILE_MODE_OTP_FACTORY:
160 			ret = mtd_read_fact_prot_reg(mtd, *ppos, len,
161 						     &retlen, kbuf);
162 			break;
163 		case MTD_FILE_MODE_OTP_USER:
164 			ret = mtd_read_user_prot_reg(mtd, *ppos, len,
165 						     &retlen, kbuf);
166 			break;
167 		case MTD_FILE_MODE_RAW:
168 		{
169 			struct mtd_oob_ops ops = {};
170 
171 			ops.mode = MTD_OPS_RAW;
172 			ops.datbuf = kbuf;
173 			ops.oobbuf = NULL;
174 			ops.len = len;
175 
176 			ret = mtd_read_oob(mtd, *ppos, &ops);
177 			retlen = ops.retlen;
178 			break;
179 		}
180 		default:
181 			ret = mtd_read(mtd, *ppos, len, &retlen, kbuf);
182 		}
183 		/* Nand returns -EBADMSG on ECC errors, but it returns
184 		 * the data. For our userspace tools it is important
185 		 * to dump areas with ECC errors!
186 		 * For kernel internal usage it also might return -EUCLEAN
187 		 * to signal the caller that a bitflip has occurred and has
188 		 * been corrected by the ECC algorithm.
189 		 * Userspace software which accesses NAND this way
190 		 * must be aware of the fact that it deals with NAND
191 		 */
192 		if (!ret || mtd_is_bitflip_or_eccerr(ret)) {
193 			*ppos += retlen;
194 			if (copy_to_user(buf, kbuf, retlen)) {
195 				kfree(kbuf);
196 				return -EFAULT;
197 			}
198 			else
199 				total_retlen += retlen;
200 
201 			count -= retlen;
202 			buf += retlen;
203 			if (retlen == 0)
204 				count = 0;
205 		}
206 		else {
207 			kfree(kbuf);
208 			return ret;
209 		}
210 
211 	}
212 
213 	kfree(kbuf);
214 	return total_retlen;
215 } /* mtdchar_read */
216 
217 static ssize_t mtdchar_write(struct file *file, const char __user *buf, size_t count,
218 			loff_t *ppos)
219 {
220 	struct mtd_file_info *mfi = file->private_data;
221 	struct mtd_info *mtd = mfi->mtd;
222 	size_t size = count;
223 	char *kbuf;
224 	size_t retlen;
225 	size_t total_retlen=0;
226 	int ret=0;
227 	int len;
228 
229 	pr_debug("MTD_write\n");
230 
231 	if (*ppos >= mtd->size)
232 		return -ENOSPC;
233 
234 	if (*ppos + count > mtd->size)
235 		count = mtd->size - *ppos;
236 
237 	if (!count)
238 		return 0;
239 
240 	kbuf = mtd_kmalloc_up_to(mtd, &size);
241 	if (!kbuf)
242 		return -ENOMEM;
243 
244 	while (count) {
245 		len = min_t(size_t, count, size);
246 
247 		if (copy_from_user(kbuf, buf, len)) {
248 			kfree(kbuf);
249 			return -EFAULT;
250 		}
251 
252 		switch (mfi->mode) {
253 		case MTD_FILE_MODE_OTP_FACTORY:
254 			ret = -EROFS;
255 			break;
256 		case MTD_FILE_MODE_OTP_USER:
257 			ret = mtd_write_user_prot_reg(mtd, *ppos, len,
258 						      &retlen, kbuf);
259 			break;
260 
261 		case MTD_FILE_MODE_RAW:
262 		{
263 			struct mtd_oob_ops ops = {};
264 
265 			ops.mode = MTD_OPS_RAW;
266 			ops.datbuf = kbuf;
267 			ops.oobbuf = NULL;
268 			ops.ooboffs = 0;
269 			ops.len = len;
270 
271 			ret = mtd_write_oob(mtd, *ppos, &ops);
272 			retlen = ops.retlen;
273 			break;
274 		}
275 
276 		default:
277 			ret = mtd_write(mtd, *ppos, len, &retlen, kbuf);
278 		}
279 
280 		/*
281 		 * Return -ENOSPC only if no data could be written at all.
282 		 * Otherwise just return the number of bytes that actually
283 		 * have been written.
284 		 */
285 		if ((ret == -ENOSPC) && (total_retlen))
286 			break;
287 
288 		if (!ret) {
289 			*ppos += retlen;
290 			total_retlen += retlen;
291 			count -= retlen;
292 			buf += retlen;
293 		}
294 		else {
295 			kfree(kbuf);
296 			return ret;
297 		}
298 	}
299 
300 	kfree(kbuf);
301 	return total_retlen;
302 } /* mtdchar_write */
303 
304 /*======================================================================
305 
306     IOCTL calls for getting device parameters.
307 
308 ======================================================================*/
309 
310 static int otp_select_filemode(struct mtd_file_info *mfi, int mode)
311 {
312 	struct mtd_info *mtd = mfi->mtd;
313 	size_t retlen;
314 
315 	switch (mode) {
316 	case MTD_OTP_FACTORY:
317 		if (mtd_read_fact_prot_reg(mtd, -1, 0, &retlen, NULL) ==
318 				-EOPNOTSUPP)
319 			return -EOPNOTSUPP;
320 
321 		mfi->mode = MTD_FILE_MODE_OTP_FACTORY;
322 		break;
323 	case MTD_OTP_USER:
324 		if (mtd_read_user_prot_reg(mtd, -1, 0, &retlen, NULL) ==
325 				-EOPNOTSUPP)
326 			return -EOPNOTSUPP;
327 
328 		mfi->mode = MTD_FILE_MODE_OTP_USER;
329 		break;
330 	case MTD_OTP_OFF:
331 		mfi->mode = MTD_FILE_MODE_NORMAL;
332 		break;
333 	default:
334 		return -EINVAL;
335 	}
336 
337 	return 0;
338 }
339 
340 static int mtdchar_writeoob(struct file *file, struct mtd_info *mtd,
341 	uint64_t start, uint32_t length, void __user *ptr,
342 	uint32_t __user *retp)
343 {
344 	struct mtd_info *master  = mtd_get_master(mtd);
345 	struct mtd_file_info *mfi = file->private_data;
346 	struct mtd_oob_ops ops = {};
347 	uint32_t retlen;
348 	int ret = 0;
349 
350 	if (length > 4096)
351 		return -EINVAL;
352 
353 	if (!master->_write_oob)
354 		return -EOPNOTSUPP;
355 
356 	ops.ooblen = length;
357 	ops.ooboffs = start & (mtd->writesize - 1);
358 	ops.datbuf = NULL;
359 	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
360 		MTD_OPS_PLACE_OOB;
361 
362 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
363 		return -EINVAL;
364 
365 	ops.oobbuf = memdup_user(ptr, length);
366 	if (IS_ERR(ops.oobbuf))
367 		return PTR_ERR(ops.oobbuf);
368 
369 	start &= ~((uint64_t)mtd->writesize - 1);
370 	ret = mtd_write_oob(mtd, start, &ops);
371 
372 	if (ops.oobretlen > 0xFFFFFFFFU)
373 		ret = -EOVERFLOW;
374 	retlen = ops.oobretlen;
375 	if (copy_to_user(retp, &retlen, sizeof(length)))
376 		ret = -EFAULT;
377 
378 	kfree(ops.oobbuf);
379 	return ret;
380 }
381 
382 static int mtdchar_readoob(struct file *file, struct mtd_info *mtd,
383 	uint64_t start, uint32_t length, void __user *ptr,
384 	uint32_t __user *retp)
385 {
386 	struct mtd_file_info *mfi = file->private_data;
387 	struct mtd_oob_ops ops = {};
388 	int ret = 0;
389 
390 	if (length > 4096)
391 		return -EINVAL;
392 
393 	ops.ooblen = length;
394 	ops.ooboffs = start & (mtd->writesize - 1);
395 	ops.datbuf = NULL;
396 	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
397 		MTD_OPS_PLACE_OOB;
398 
399 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
400 		return -EINVAL;
401 
402 	ops.oobbuf = kmalloc(length, GFP_KERNEL);
403 	if (!ops.oobbuf)
404 		return -ENOMEM;
405 
406 	start &= ~((uint64_t)mtd->writesize - 1);
407 	ret = mtd_read_oob(mtd, start, &ops);
408 
409 	if (put_user(ops.oobretlen, retp))
410 		ret = -EFAULT;
411 	else if (ops.oobretlen && copy_to_user(ptr, ops.oobbuf,
412 					    ops.oobretlen))
413 		ret = -EFAULT;
414 
415 	kfree(ops.oobbuf);
416 
417 	/*
418 	 * NAND returns -EBADMSG on ECC errors, but it returns the OOB
419 	 * data. For our userspace tools it is important to dump areas
420 	 * with ECC errors!
421 	 * For kernel internal usage it also might return -EUCLEAN
422 	 * to signal the caller that a bitflip has occurred and has
423 	 * been corrected by the ECC algorithm.
424 	 *
425 	 * Note: currently the standard NAND function, nand_read_oob_std,
426 	 * does not calculate ECC for the OOB area, so do not rely on
427 	 * this behavior unless you have replaced it with your own.
428 	 */
429 	if (mtd_is_bitflip_or_eccerr(ret))
430 		return 0;
431 
432 	return ret;
433 }
434 
435 /*
436  * Copies (and truncates, if necessary) OOB layout information to the
437  * deprecated layout struct, nand_ecclayout_user. This is necessary only to
438  * support the deprecated API ioctl ECCGETLAYOUT while allowing all new
439  * functionality to use mtd_ooblayout_ops flexibly (i.e. mtd_ooblayout_ops
440  * can describe any kind of OOB layout with almost zero overhead from a
441  * memory usage point of view).
442  */
443 static int shrink_ecclayout(struct mtd_info *mtd,
444 			    struct nand_ecclayout_user *to)
445 {
446 	struct mtd_oob_region oobregion;
447 	int i, section = 0, ret;
448 
449 	if (!mtd || !to)
450 		return -EINVAL;
451 
452 	memset(to, 0, sizeof(*to));
453 
454 	to->eccbytes = 0;
455 	for (i = 0; i < MTD_MAX_ECCPOS_ENTRIES;) {
456 		u32 eccpos;
457 
458 		ret = mtd_ooblayout_ecc(mtd, section++, &oobregion);
459 		if (ret < 0) {
460 			if (ret != -ERANGE)
461 				return ret;
462 
463 			break;
464 		}
465 
466 		eccpos = oobregion.offset;
467 		for (; i < MTD_MAX_ECCPOS_ENTRIES &&
468 		       eccpos < oobregion.offset + oobregion.length; i++) {
469 			to->eccpos[i] = eccpos++;
470 			to->eccbytes++;
471 		}
472 	}
473 
474 	for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES; i++) {
475 		ret = mtd_ooblayout_free(mtd, i, &oobregion);
476 		if (ret < 0) {
477 			if (ret != -ERANGE)
478 				return ret;
479 
480 			break;
481 		}
482 
483 		to->oobfree[i].offset = oobregion.offset;
484 		to->oobfree[i].length = oobregion.length;
485 		to->oobavail += to->oobfree[i].length;
486 	}
487 
488 	return 0;
489 }
490 
491 static int get_oobinfo(struct mtd_info *mtd, struct nand_oobinfo *to)
492 {
493 	struct mtd_oob_region oobregion;
494 	int i, section = 0, ret;
495 
496 	if (!mtd || !to)
497 		return -EINVAL;
498 
499 	memset(to, 0, sizeof(*to));
500 
501 	to->eccbytes = 0;
502 	for (i = 0; i < ARRAY_SIZE(to->eccpos);) {
503 		u32 eccpos;
504 
505 		ret = mtd_ooblayout_ecc(mtd, section++, &oobregion);
506 		if (ret < 0) {
507 			if (ret != -ERANGE)
508 				return ret;
509 
510 			break;
511 		}
512 
513 		if (oobregion.length + i > ARRAY_SIZE(to->eccpos))
514 			return -EINVAL;
515 
516 		eccpos = oobregion.offset;
517 		for (; eccpos < oobregion.offset + oobregion.length; i++) {
518 			to->eccpos[i] = eccpos++;
519 			to->eccbytes++;
520 		}
521 	}
522 
523 	for (i = 0; i < 8; i++) {
524 		ret = mtd_ooblayout_free(mtd, i, &oobregion);
525 		if (ret < 0) {
526 			if (ret != -ERANGE)
527 				return ret;
528 
529 			break;
530 		}
531 
532 		to->oobfree[i][0] = oobregion.offset;
533 		to->oobfree[i][1] = oobregion.length;
534 	}
535 
536 	to->useecc = MTD_NANDECC_AUTOPLACE;
537 
538 	return 0;
539 }
540 
541 static int mtdchar_blkpg_ioctl(struct mtd_info *mtd,
542 			       struct blkpg_ioctl_arg *arg)
543 {
544 	struct blkpg_partition p;
545 
546 	if (!capable(CAP_SYS_ADMIN))
547 		return -EPERM;
548 
549 	if (copy_from_user(&p, arg->data, sizeof(p)))
550 		return -EFAULT;
551 
552 	switch (arg->op) {
553 	case BLKPG_ADD_PARTITION:
554 
555 		/* Only master mtd device must be used to add partitions */
556 		if (mtd_is_partition(mtd))
557 			return -EINVAL;
558 
559 		/* Sanitize user input */
560 		p.devname[BLKPG_DEVNAMELTH - 1] = '\0';
561 
562 		return mtd_add_partition(mtd, p.devname, p.start, p.length);
563 
564 	case BLKPG_DEL_PARTITION:
565 
566 		if (p.pno < 0)
567 			return -EINVAL;
568 
569 		return mtd_del_partition(mtd, p.pno);
570 
571 	default:
572 		return -EINVAL;
573 	}
574 }
575 
576 static void adjust_oob_length(struct mtd_info *mtd, uint64_t start,
577 			      struct mtd_oob_ops *ops)
578 {
579 	uint32_t start_page, end_page;
580 	u32 oob_per_page;
581 
582 	if (ops->len == 0 || ops->ooblen == 0)
583 		return;
584 
585 	start_page = mtd_div_by_ws(start, mtd);
586 	end_page = mtd_div_by_ws(start + ops->len - 1, mtd);
587 	oob_per_page = mtd_oobavail(mtd, ops);
588 
589 	ops->ooblen = min_t(size_t, ops->ooblen,
590 			    (end_page - start_page + 1) * oob_per_page);
591 }
592 
593 static int mtdchar_write_ioctl(struct mtd_info *mtd,
594 		struct mtd_write_req __user *argp)
595 {
596 	struct mtd_info *master = mtd_get_master(mtd);
597 	struct mtd_write_req req;
598 	const void __user *usr_data, *usr_oob;
599 	uint8_t *datbuf = NULL, *oobbuf = NULL;
600 	size_t datbuf_len, oobbuf_len;
601 	int ret = 0;
602 
603 	if (copy_from_user(&req, argp, sizeof(req)))
604 		return -EFAULT;
605 
606 	usr_data = (const void __user *)(uintptr_t)req.usr_data;
607 	usr_oob = (const void __user *)(uintptr_t)req.usr_oob;
608 
609 	if (!master->_write_oob)
610 		return -EOPNOTSUPP;
611 
612 	if (!usr_data)
613 		req.len = 0;
614 
615 	if (!usr_oob)
616 		req.ooblen = 0;
617 
618 	req.len &= 0xffffffff;
619 	req.ooblen &= 0xffffffff;
620 
621 	if (req.start + req.len > mtd->size)
622 		return -EINVAL;
623 
624 	datbuf_len = min_t(size_t, req.len, mtd->erasesize);
625 	if (datbuf_len > 0) {
626 		datbuf = kvmalloc(datbuf_len, GFP_KERNEL);
627 		if (!datbuf)
628 			return -ENOMEM;
629 	}
630 
631 	oobbuf_len = min_t(size_t, req.ooblen, mtd->erasesize);
632 	if (oobbuf_len > 0) {
633 		oobbuf = kvmalloc(oobbuf_len, GFP_KERNEL);
634 		if (!oobbuf) {
635 			kvfree(datbuf);
636 			return -ENOMEM;
637 		}
638 	}
639 
640 	while (req.len > 0 || (!usr_data && req.ooblen > 0)) {
641 		struct mtd_oob_ops ops = {
642 			.mode = req.mode,
643 			.len = min_t(size_t, req.len, datbuf_len),
644 			.ooblen = min_t(size_t, req.ooblen, oobbuf_len),
645 			.datbuf = datbuf,
646 			.oobbuf = oobbuf,
647 		};
648 
649 		/*
650 		 * Shorten non-page-aligned, eraseblock-sized writes so that
651 		 * the write ends on an eraseblock boundary.  This is necessary
652 		 * for adjust_oob_length() to properly handle non-page-aligned
653 		 * writes.
654 		 */
655 		if (ops.len == mtd->erasesize)
656 			ops.len -= mtd_mod_by_ws(req.start + ops.len, mtd);
657 
658 		/*
659 		 * For writes which are not OOB-only, adjust the amount of OOB
660 		 * data written according to the number of data pages written.
661 		 * This is necessary to prevent OOB data from being skipped
662 		 * over in data+OOB writes requiring multiple mtd_write_oob()
663 		 * calls to be completed.
664 		 */
665 		adjust_oob_length(mtd, req.start, &ops);
666 
667 		if (copy_from_user(datbuf, usr_data, ops.len) ||
668 		    copy_from_user(oobbuf, usr_oob, ops.ooblen)) {
669 			ret = -EFAULT;
670 			break;
671 		}
672 
673 		ret = mtd_write_oob(mtd, req.start, &ops);
674 		if (ret)
675 			break;
676 
677 		req.start += ops.retlen;
678 		req.len -= ops.retlen;
679 		usr_data += ops.retlen;
680 
681 		req.ooblen -= ops.oobretlen;
682 		usr_oob += ops.oobretlen;
683 	}
684 
685 	kvfree(datbuf);
686 	kvfree(oobbuf);
687 
688 	return ret;
689 }
690 
691 static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg)
692 {
693 	struct mtd_file_info *mfi = file->private_data;
694 	struct mtd_info *mtd = mfi->mtd;
695 	struct mtd_info *master = mtd_get_master(mtd);
696 	void __user *argp = (void __user *)arg;
697 	int ret = 0;
698 	struct mtd_info_user info;
699 
700 	pr_debug("MTD_ioctl\n");
701 
702 	/*
703 	 * Check the file mode to require "dangerous" commands to have write
704 	 * permissions.
705 	 */
706 	switch (cmd) {
707 	/* "safe" commands */
708 	case MEMGETREGIONCOUNT:
709 	case MEMGETREGIONINFO:
710 	case MEMGETINFO:
711 	case MEMREADOOB:
712 	case MEMREADOOB64:
713 	case MEMISLOCKED:
714 	case MEMGETOOBSEL:
715 	case MEMGETBADBLOCK:
716 	case OTPSELECT:
717 	case OTPGETREGIONCOUNT:
718 	case OTPGETREGIONINFO:
719 	case ECCGETLAYOUT:
720 	case ECCGETSTATS:
721 	case MTDFILEMODE:
722 	case BLKPG:
723 	case BLKRRPART:
724 		break;
725 
726 	/* "dangerous" commands */
727 	case MEMERASE:
728 	case MEMERASE64:
729 	case MEMLOCK:
730 	case MEMUNLOCK:
731 	case MEMSETBADBLOCK:
732 	case MEMWRITEOOB:
733 	case MEMWRITEOOB64:
734 	case MEMWRITE:
735 	case OTPLOCK:
736 	case OTPERASE:
737 		if (!(file->f_mode & FMODE_WRITE))
738 			return -EPERM;
739 		break;
740 
741 	default:
742 		return -ENOTTY;
743 	}
744 
745 	switch (cmd) {
746 	case MEMGETREGIONCOUNT:
747 		if (copy_to_user(argp, &(mtd->numeraseregions), sizeof(int)))
748 			return -EFAULT;
749 		break;
750 
751 	case MEMGETREGIONINFO:
752 	{
753 		uint32_t ur_idx;
754 		struct mtd_erase_region_info *kr;
755 		struct region_info_user __user *ur = argp;
756 
757 		if (get_user(ur_idx, &(ur->regionindex)))
758 			return -EFAULT;
759 
760 		if (ur_idx >= mtd->numeraseregions)
761 			return -EINVAL;
762 
763 		kr = &(mtd->eraseregions[ur_idx]);
764 
765 		if (put_user(kr->offset, &(ur->offset))
766 		    || put_user(kr->erasesize, &(ur->erasesize))
767 		    || put_user(kr->numblocks, &(ur->numblocks)))
768 			return -EFAULT;
769 
770 		break;
771 	}
772 
773 	case MEMGETINFO:
774 		memset(&info, 0, sizeof(info));
775 		info.type	= mtd->type;
776 		info.flags	= mtd->flags;
777 		info.size	= mtd->size;
778 		info.erasesize	= mtd->erasesize;
779 		info.writesize	= mtd->writesize;
780 		info.oobsize	= mtd->oobsize;
781 		/* The below field is obsolete */
782 		info.padding	= 0;
783 		if (copy_to_user(argp, &info, sizeof(struct mtd_info_user)))
784 			return -EFAULT;
785 		break;
786 
787 	case MEMERASE:
788 	case MEMERASE64:
789 	{
790 		struct erase_info *erase;
791 
792 		erase=kzalloc(sizeof(struct erase_info),GFP_KERNEL);
793 		if (!erase)
794 			ret = -ENOMEM;
795 		else {
796 			if (cmd == MEMERASE64) {
797 				struct erase_info_user64 einfo64;
798 
799 				if (copy_from_user(&einfo64, argp,
800 					    sizeof(struct erase_info_user64))) {
801 					kfree(erase);
802 					return -EFAULT;
803 				}
804 				erase->addr = einfo64.start;
805 				erase->len = einfo64.length;
806 			} else {
807 				struct erase_info_user einfo32;
808 
809 				if (copy_from_user(&einfo32, argp,
810 					    sizeof(struct erase_info_user))) {
811 					kfree(erase);
812 					return -EFAULT;
813 				}
814 				erase->addr = einfo32.start;
815 				erase->len = einfo32.length;
816 			}
817 
818 			ret = mtd_erase(mtd, erase);
819 			kfree(erase);
820 		}
821 		break;
822 	}
823 
824 	case MEMWRITEOOB:
825 	{
826 		struct mtd_oob_buf buf;
827 		struct mtd_oob_buf __user *buf_user = argp;
828 
829 		/* NOTE: writes return length to buf_user->length */
830 		if (copy_from_user(&buf, argp, sizeof(buf)))
831 			ret = -EFAULT;
832 		else
833 			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
834 				buf.ptr, &buf_user->length);
835 		break;
836 	}
837 
838 	case MEMREADOOB:
839 	{
840 		struct mtd_oob_buf buf;
841 		struct mtd_oob_buf __user *buf_user = argp;
842 
843 		/* NOTE: writes return length to buf_user->start */
844 		if (copy_from_user(&buf, argp, sizeof(buf)))
845 			ret = -EFAULT;
846 		else
847 			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
848 				buf.ptr, &buf_user->start);
849 		break;
850 	}
851 
852 	case MEMWRITEOOB64:
853 	{
854 		struct mtd_oob_buf64 buf;
855 		struct mtd_oob_buf64 __user *buf_user = argp;
856 
857 		if (copy_from_user(&buf, argp, sizeof(buf)))
858 			ret = -EFAULT;
859 		else
860 			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
861 				(void __user *)(uintptr_t)buf.usr_ptr,
862 				&buf_user->length);
863 		break;
864 	}
865 
866 	case MEMREADOOB64:
867 	{
868 		struct mtd_oob_buf64 buf;
869 		struct mtd_oob_buf64 __user *buf_user = argp;
870 
871 		if (copy_from_user(&buf, argp, sizeof(buf)))
872 			ret = -EFAULT;
873 		else
874 			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
875 				(void __user *)(uintptr_t)buf.usr_ptr,
876 				&buf_user->length);
877 		break;
878 	}
879 
880 	case MEMWRITE:
881 	{
882 		ret = mtdchar_write_ioctl(mtd,
883 		      (struct mtd_write_req __user *)arg);
884 		break;
885 	}
886 
887 	case MEMLOCK:
888 	{
889 		struct erase_info_user einfo;
890 
891 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
892 			return -EFAULT;
893 
894 		ret = mtd_lock(mtd, einfo.start, einfo.length);
895 		break;
896 	}
897 
898 	case MEMUNLOCK:
899 	{
900 		struct erase_info_user einfo;
901 
902 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
903 			return -EFAULT;
904 
905 		ret = mtd_unlock(mtd, einfo.start, einfo.length);
906 		break;
907 	}
908 
909 	case MEMISLOCKED:
910 	{
911 		struct erase_info_user einfo;
912 
913 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
914 			return -EFAULT;
915 
916 		ret = mtd_is_locked(mtd, einfo.start, einfo.length);
917 		break;
918 	}
919 
920 	/* Legacy interface */
921 	case MEMGETOOBSEL:
922 	{
923 		struct nand_oobinfo oi;
924 
925 		if (!master->ooblayout)
926 			return -EOPNOTSUPP;
927 
928 		ret = get_oobinfo(mtd, &oi);
929 		if (ret)
930 			return ret;
931 
932 		if (copy_to_user(argp, &oi, sizeof(struct nand_oobinfo)))
933 			return -EFAULT;
934 		break;
935 	}
936 
937 	case MEMGETBADBLOCK:
938 	{
939 		loff_t offs;
940 
941 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
942 			return -EFAULT;
943 		return mtd_block_isbad(mtd, offs);
944 	}
945 
946 	case MEMSETBADBLOCK:
947 	{
948 		loff_t offs;
949 
950 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
951 			return -EFAULT;
952 		return mtd_block_markbad(mtd, offs);
953 	}
954 
955 	case OTPSELECT:
956 	{
957 		int mode;
958 		if (copy_from_user(&mode, argp, sizeof(int)))
959 			return -EFAULT;
960 
961 		mfi->mode = MTD_FILE_MODE_NORMAL;
962 
963 		ret = otp_select_filemode(mfi, mode);
964 
965 		file->f_pos = 0;
966 		break;
967 	}
968 
969 	case OTPGETREGIONCOUNT:
970 	case OTPGETREGIONINFO:
971 	{
972 		struct otp_info *buf = kmalloc(4096, GFP_KERNEL);
973 		size_t retlen;
974 		if (!buf)
975 			return -ENOMEM;
976 		switch (mfi->mode) {
977 		case MTD_FILE_MODE_OTP_FACTORY:
978 			ret = mtd_get_fact_prot_info(mtd, 4096, &retlen, buf);
979 			break;
980 		case MTD_FILE_MODE_OTP_USER:
981 			ret = mtd_get_user_prot_info(mtd, 4096, &retlen, buf);
982 			break;
983 		default:
984 			ret = -EINVAL;
985 			break;
986 		}
987 		if (!ret) {
988 			if (cmd == OTPGETREGIONCOUNT) {
989 				int nbr = retlen / sizeof(struct otp_info);
990 				ret = copy_to_user(argp, &nbr, sizeof(int));
991 			} else
992 				ret = copy_to_user(argp, buf, retlen);
993 			if (ret)
994 				ret = -EFAULT;
995 		}
996 		kfree(buf);
997 		break;
998 	}
999 
1000 	case OTPLOCK:
1001 	case OTPERASE:
1002 	{
1003 		struct otp_info oinfo;
1004 
1005 		if (mfi->mode != MTD_FILE_MODE_OTP_USER)
1006 			return -EINVAL;
1007 		if (copy_from_user(&oinfo, argp, sizeof(oinfo)))
1008 			return -EFAULT;
1009 		if (cmd == OTPLOCK)
1010 			ret = mtd_lock_user_prot_reg(mtd, oinfo.start, oinfo.length);
1011 		else
1012 			ret = mtd_erase_user_prot_reg(mtd, oinfo.start, oinfo.length);
1013 		break;
1014 	}
1015 
1016 	/* This ioctl is being deprecated - it truncates the ECC layout */
1017 	case ECCGETLAYOUT:
1018 	{
1019 		struct nand_ecclayout_user *usrlay;
1020 
1021 		if (!master->ooblayout)
1022 			return -EOPNOTSUPP;
1023 
1024 		usrlay = kmalloc(sizeof(*usrlay), GFP_KERNEL);
1025 		if (!usrlay)
1026 			return -ENOMEM;
1027 
1028 		shrink_ecclayout(mtd, usrlay);
1029 
1030 		if (copy_to_user(argp, usrlay, sizeof(*usrlay)))
1031 			ret = -EFAULT;
1032 		kfree(usrlay);
1033 		break;
1034 	}
1035 
1036 	case ECCGETSTATS:
1037 	{
1038 		if (copy_to_user(argp, &mtd->ecc_stats,
1039 				 sizeof(struct mtd_ecc_stats)))
1040 			return -EFAULT;
1041 		break;
1042 	}
1043 
1044 	case MTDFILEMODE:
1045 	{
1046 		mfi->mode = 0;
1047 
1048 		switch(arg) {
1049 		case MTD_FILE_MODE_OTP_FACTORY:
1050 		case MTD_FILE_MODE_OTP_USER:
1051 			ret = otp_select_filemode(mfi, arg);
1052 			break;
1053 
1054 		case MTD_FILE_MODE_RAW:
1055 			if (!mtd_has_oob(mtd))
1056 				return -EOPNOTSUPP;
1057 			mfi->mode = arg;
1058 			break;
1059 
1060 		case MTD_FILE_MODE_NORMAL:
1061 			break;
1062 		default:
1063 			ret = -EINVAL;
1064 		}
1065 		file->f_pos = 0;
1066 		break;
1067 	}
1068 
1069 	case BLKPG:
1070 	{
1071 		struct blkpg_ioctl_arg __user *blk_arg = argp;
1072 		struct blkpg_ioctl_arg a;
1073 
1074 		if (copy_from_user(&a, blk_arg, sizeof(a)))
1075 			ret = -EFAULT;
1076 		else
1077 			ret = mtdchar_blkpg_ioctl(mtd, &a);
1078 		break;
1079 	}
1080 
1081 	case BLKRRPART:
1082 	{
1083 		/* No reread partition feature. Just return ok */
1084 		ret = 0;
1085 		break;
1086 	}
1087 	}
1088 
1089 	return ret;
1090 } /* memory_ioctl */
1091 
1092 static long mtdchar_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
1093 {
1094 	struct mtd_file_info *mfi = file->private_data;
1095 	struct mtd_info *mtd = mfi->mtd;
1096 	struct mtd_info *master = mtd_get_master(mtd);
1097 	int ret;
1098 
1099 	mutex_lock(&master->master.chrdev_lock);
1100 	ret = mtdchar_ioctl(file, cmd, arg);
1101 	mutex_unlock(&master->master.chrdev_lock);
1102 
1103 	return ret;
1104 }
1105 
1106 #ifdef CONFIG_COMPAT
1107 
1108 struct mtd_oob_buf32 {
1109 	u_int32_t start;
1110 	u_int32_t length;
1111 	compat_caddr_t ptr;	/* unsigned char* */
1112 };
1113 
1114 #define MEMWRITEOOB32		_IOWR('M', 3, struct mtd_oob_buf32)
1115 #define MEMREADOOB32		_IOWR('M', 4, struct mtd_oob_buf32)
1116 
1117 static long mtdchar_compat_ioctl(struct file *file, unsigned int cmd,
1118 	unsigned long arg)
1119 {
1120 	struct mtd_file_info *mfi = file->private_data;
1121 	struct mtd_info *mtd = mfi->mtd;
1122 	struct mtd_info *master = mtd_get_master(mtd);
1123 	void __user *argp = compat_ptr(arg);
1124 	int ret = 0;
1125 
1126 	mutex_lock(&master->master.chrdev_lock);
1127 
1128 	switch (cmd) {
1129 	case MEMWRITEOOB32:
1130 	{
1131 		struct mtd_oob_buf32 buf;
1132 		struct mtd_oob_buf32 __user *buf_user = argp;
1133 
1134 		if (!(file->f_mode & FMODE_WRITE)) {
1135 			ret = -EPERM;
1136 			break;
1137 		}
1138 
1139 		if (copy_from_user(&buf, argp, sizeof(buf)))
1140 			ret = -EFAULT;
1141 		else
1142 			ret = mtdchar_writeoob(file, mtd, buf.start,
1143 				buf.length, compat_ptr(buf.ptr),
1144 				&buf_user->length);
1145 		break;
1146 	}
1147 
1148 	case MEMREADOOB32:
1149 	{
1150 		struct mtd_oob_buf32 buf;
1151 		struct mtd_oob_buf32 __user *buf_user = argp;
1152 
1153 		/* NOTE: writes return length to buf->start */
1154 		if (copy_from_user(&buf, argp, sizeof(buf)))
1155 			ret = -EFAULT;
1156 		else
1157 			ret = mtdchar_readoob(file, mtd, buf.start,
1158 				buf.length, compat_ptr(buf.ptr),
1159 				&buf_user->start);
1160 		break;
1161 	}
1162 
1163 	case BLKPG:
1164 	{
1165 		/* Convert from blkpg_compat_ioctl_arg to blkpg_ioctl_arg */
1166 		struct blkpg_compat_ioctl_arg __user *uarg = argp;
1167 		struct blkpg_compat_ioctl_arg compat_arg;
1168 		struct blkpg_ioctl_arg a;
1169 
1170 		if (copy_from_user(&compat_arg, uarg, sizeof(compat_arg))) {
1171 			ret = -EFAULT;
1172 			break;
1173 		}
1174 
1175 		memset(&a, 0, sizeof(a));
1176 		a.op = compat_arg.op;
1177 		a.flags = compat_arg.flags;
1178 		a.datalen = compat_arg.datalen;
1179 		a.data = compat_ptr(compat_arg.data);
1180 
1181 		ret = mtdchar_blkpg_ioctl(mtd, &a);
1182 		break;
1183 	}
1184 
1185 	default:
1186 		ret = mtdchar_ioctl(file, cmd, (unsigned long)argp);
1187 	}
1188 
1189 	mutex_unlock(&master->master.chrdev_lock);
1190 
1191 	return ret;
1192 }
1193 
1194 #endif /* CONFIG_COMPAT */
1195 
1196 /*
1197  * try to determine where a shared mapping can be made
1198  * - only supported for NOMMU at the moment (MMU can't doesn't copy private
1199  *   mappings)
1200  */
1201 #ifndef CONFIG_MMU
1202 static unsigned long mtdchar_get_unmapped_area(struct file *file,
1203 					   unsigned long addr,
1204 					   unsigned long len,
1205 					   unsigned long pgoff,
1206 					   unsigned long flags)
1207 {
1208 	struct mtd_file_info *mfi = file->private_data;
1209 	struct mtd_info *mtd = mfi->mtd;
1210 	unsigned long offset;
1211 	int ret;
1212 
1213 	if (addr != 0)
1214 		return (unsigned long) -EINVAL;
1215 
1216 	if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT))
1217 		return (unsigned long) -EINVAL;
1218 
1219 	offset = pgoff << PAGE_SHIFT;
1220 	if (offset > mtd->size - len)
1221 		return (unsigned long) -EINVAL;
1222 
1223 	ret = mtd_get_unmapped_area(mtd, len, offset, flags);
1224 	return ret == -EOPNOTSUPP ? -ENODEV : ret;
1225 }
1226 
1227 static unsigned mtdchar_mmap_capabilities(struct file *file)
1228 {
1229 	struct mtd_file_info *mfi = file->private_data;
1230 
1231 	return mtd_mmap_capabilities(mfi->mtd);
1232 }
1233 #endif
1234 
1235 /*
1236  * set up a mapping for shared memory segments
1237  */
1238 static int mtdchar_mmap(struct file *file, struct vm_area_struct *vma)
1239 {
1240 #ifdef CONFIG_MMU
1241 	struct mtd_file_info *mfi = file->private_data;
1242 	struct mtd_info *mtd = mfi->mtd;
1243 	struct map_info *map = mtd->priv;
1244 
1245         /* This is broken because it assumes the MTD device is map-based
1246 	   and that mtd->priv is a valid struct map_info.  It should be
1247 	   replaced with something that uses the mtd_get_unmapped_area()
1248 	   operation properly. */
1249 	if (0 /*mtd->type == MTD_RAM || mtd->type == MTD_ROM*/) {
1250 #ifdef pgprot_noncached
1251 		if (file->f_flags & O_DSYNC || map->phys >= __pa(high_memory))
1252 			vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1253 #endif
1254 		return vm_iomap_memory(vma, map->phys, map->size);
1255 	}
1256 	return -ENODEV;
1257 #else
1258 	return vma->vm_flags & VM_SHARED ? 0 : -EACCES;
1259 #endif
1260 }
1261 
1262 static const struct file_operations mtd_fops = {
1263 	.owner		= THIS_MODULE,
1264 	.llseek		= mtdchar_lseek,
1265 	.read		= mtdchar_read,
1266 	.write		= mtdchar_write,
1267 	.unlocked_ioctl	= mtdchar_unlocked_ioctl,
1268 #ifdef CONFIG_COMPAT
1269 	.compat_ioctl	= mtdchar_compat_ioctl,
1270 #endif
1271 	.open		= mtdchar_open,
1272 	.release	= mtdchar_close,
1273 	.mmap		= mtdchar_mmap,
1274 #ifndef CONFIG_MMU
1275 	.get_unmapped_area = mtdchar_get_unmapped_area,
1276 	.mmap_capabilities = mtdchar_mmap_capabilities,
1277 #endif
1278 };
1279 
1280 int __init init_mtdchar(void)
1281 {
1282 	int ret;
1283 
1284 	ret = __register_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS,
1285 				   "mtd", &mtd_fops);
1286 	if (ret < 0) {
1287 		pr_err("Can't allocate major number %d for MTD\n",
1288 		       MTD_CHAR_MAJOR);
1289 		return ret;
1290 	}
1291 
1292 	return ret;
1293 }
1294 
1295 void __exit cleanup_mtdchar(void)
1296 {
1297 	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1298 }
1299 
1300 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);
1301