xref: /openbmc/linux/drivers/mtd/mtdchar.c (revision 4c5a116a)
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 (length > 4096)
359 		return -EINVAL;
360 
361 	if (!master->_write_oob)
362 		return -EOPNOTSUPP;
363 
364 	ops.ooblen = length;
365 	ops.ooboffs = start & (mtd->writesize - 1);
366 	ops.datbuf = NULL;
367 	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
368 		MTD_OPS_PLACE_OOB;
369 
370 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
371 		return -EINVAL;
372 
373 	ops.oobbuf = memdup_user(ptr, length);
374 	if (IS_ERR(ops.oobbuf))
375 		return PTR_ERR(ops.oobbuf);
376 
377 	start &= ~((uint64_t)mtd->writesize - 1);
378 	ret = mtd_write_oob(mtd, start, &ops);
379 
380 	if (ops.oobretlen > 0xFFFFFFFFU)
381 		ret = -EOVERFLOW;
382 	retlen = ops.oobretlen;
383 	if (copy_to_user(retp, &retlen, sizeof(length)))
384 		ret = -EFAULT;
385 
386 	kfree(ops.oobbuf);
387 	return ret;
388 }
389 
390 static int mtdchar_readoob(struct file *file, struct mtd_info *mtd,
391 	uint64_t start, uint32_t length, void __user *ptr,
392 	uint32_t __user *retp)
393 {
394 	struct mtd_file_info *mfi = file->private_data;
395 	struct mtd_oob_ops ops = {};
396 	int ret = 0;
397 
398 	if (length > 4096)
399 		return -EINVAL;
400 
401 	ops.ooblen = length;
402 	ops.ooboffs = start & (mtd->writesize - 1);
403 	ops.datbuf = NULL;
404 	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
405 		MTD_OPS_PLACE_OOB;
406 
407 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
408 		return -EINVAL;
409 
410 	ops.oobbuf = kmalloc(length, GFP_KERNEL);
411 	if (!ops.oobbuf)
412 		return -ENOMEM;
413 
414 	start &= ~((uint64_t)mtd->writesize - 1);
415 	ret = mtd_read_oob(mtd, start, &ops);
416 
417 	if (put_user(ops.oobretlen, retp))
418 		ret = -EFAULT;
419 	else if (ops.oobretlen && copy_to_user(ptr, ops.oobbuf,
420 					    ops.oobretlen))
421 		ret = -EFAULT;
422 
423 	kfree(ops.oobbuf);
424 
425 	/*
426 	 * NAND returns -EBADMSG on ECC errors, but it returns the OOB
427 	 * data. For our userspace tools it is important to dump areas
428 	 * with ECC errors!
429 	 * For kernel internal usage it also might return -EUCLEAN
430 	 * to signal the caller that a bitflip has occurred and has
431 	 * been corrected by the ECC algorithm.
432 	 *
433 	 * Note: currently the standard NAND function, nand_read_oob_std,
434 	 * does not calculate ECC for the OOB area, so do not rely on
435 	 * this behavior unless you have replaced it with your own.
436 	 */
437 	if (mtd_is_bitflip_or_eccerr(ret))
438 		return 0;
439 
440 	return ret;
441 }
442 
443 /*
444  * Copies (and truncates, if necessary) OOB layout information to the
445  * deprecated layout struct, nand_ecclayout_user. This is necessary only to
446  * support the deprecated API ioctl ECCGETLAYOUT while allowing all new
447  * functionality to use mtd_ooblayout_ops flexibly (i.e. mtd_ooblayout_ops
448  * can describe any kind of OOB layout with almost zero overhead from a
449  * memory usage point of view).
450  */
451 static int shrink_ecclayout(struct mtd_info *mtd,
452 			    struct nand_ecclayout_user *to)
453 {
454 	struct mtd_oob_region oobregion;
455 	int i, section = 0, ret;
456 
457 	if (!mtd || !to)
458 		return -EINVAL;
459 
460 	memset(to, 0, sizeof(*to));
461 
462 	to->eccbytes = 0;
463 	for (i = 0; i < MTD_MAX_ECCPOS_ENTRIES;) {
464 		u32 eccpos;
465 
466 		ret = mtd_ooblayout_ecc(mtd, section++, &oobregion);
467 		if (ret < 0) {
468 			if (ret != -ERANGE)
469 				return ret;
470 
471 			break;
472 		}
473 
474 		eccpos = oobregion.offset;
475 		for (; i < MTD_MAX_ECCPOS_ENTRIES &&
476 		       eccpos < oobregion.offset + oobregion.length; i++) {
477 			to->eccpos[i] = eccpos++;
478 			to->eccbytes++;
479 		}
480 	}
481 
482 	for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES; i++) {
483 		ret = mtd_ooblayout_free(mtd, i, &oobregion);
484 		if (ret < 0) {
485 			if (ret != -ERANGE)
486 				return ret;
487 
488 			break;
489 		}
490 
491 		to->oobfree[i].offset = oobregion.offset;
492 		to->oobfree[i].length = oobregion.length;
493 		to->oobavail += to->oobfree[i].length;
494 	}
495 
496 	return 0;
497 }
498 
499 static int get_oobinfo(struct mtd_info *mtd, struct nand_oobinfo *to)
500 {
501 	struct mtd_oob_region oobregion;
502 	int i, section = 0, ret;
503 
504 	if (!mtd || !to)
505 		return -EINVAL;
506 
507 	memset(to, 0, sizeof(*to));
508 
509 	to->eccbytes = 0;
510 	for (i = 0; i < ARRAY_SIZE(to->eccpos);) {
511 		u32 eccpos;
512 
513 		ret = mtd_ooblayout_ecc(mtd, section++, &oobregion);
514 		if (ret < 0) {
515 			if (ret != -ERANGE)
516 				return ret;
517 
518 			break;
519 		}
520 
521 		if (oobregion.length + i > ARRAY_SIZE(to->eccpos))
522 			return -EINVAL;
523 
524 		eccpos = oobregion.offset;
525 		for (; eccpos < oobregion.offset + oobregion.length; i++) {
526 			to->eccpos[i] = eccpos++;
527 			to->eccbytes++;
528 		}
529 	}
530 
531 	for (i = 0; i < 8; i++) {
532 		ret = mtd_ooblayout_free(mtd, i, &oobregion);
533 		if (ret < 0) {
534 			if (ret != -ERANGE)
535 				return ret;
536 
537 			break;
538 		}
539 
540 		to->oobfree[i][0] = oobregion.offset;
541 		to->oobfree[i][1] = oobregion.length;
542 	}
543 
544 	to->useecc = MTD_NANDECC_AUTOPLACE;
545 
546 	return 0;
547 }
548 
549 static int mtdchar_blkpg_ioctl(struct mtd_info *mtd,
550 			       struct blkpg_ioctl_arg *arg)
551 {
552 	struct blkpg_partition p;
553 
554 	if (!capable(CAP_SYS_ADMIN))
555 		return -EPERM;
556 
557 	if (copy_from_user(&p, arg->data, sizeof(p)))
558 		return -EFAULT;
559 
560 	switch (arg->op) {
561 	case BLKPG_ADD_PARTITION:
562 
563 		/* Only master mtd device must be used to add partitions */
564 		if (mtd_is_partition(mtd))
565 			return -EINVAL;
566 
567 		/* Sanitize user input */
568 		p.devname[BLKPG_DEVNAMELTH - 1] = '\0';
569 
570 		return mtd_add_partition(mtd, p.devname, p.start, p.length);
571 
572 	case BLKPG_DEL_PARTITION:
573 
574 		if (p.pno < 0)
575 			return -EINVAL;
576 
577 		return mtd_del_partition(mtd, p.pno);
578 
579 	default:
580 		return -EINVAL;
581 	}
582 }
583 
584 static int mtdchar_write_ioctl(struct mtd_info *mtd,
585 		struct mtd_write_req __user *argp)
586 {
587 	struct mtd_info *master = mtd_get_master(mtd);
588 	struct mtd_write_req req;
589 	struct mtd_oob_ops ops = {};
590 	const void __user *usr_data, *usr_oob;
591 	int ret;
592 
593 	if (copy_from_user(&req, argp, sizeof(req)))
594 		return -EFAULT;
595 
596 	usr_data = (const void __user *)(uintptr_t)req.usr_data;
597 	usr_oob = (const void __user *)(uintptr_t)req.usr_oob;
598 
599 	if (!master->_write_oob)
600 		return -EOPNOTSUPP;
601 	ops.mode = req.mode;
602 	ops.len = (size_t)req.len;
603 	ops.ooblen = (size_t)req.ooblen;
604 	ops.ooboffs = 0;
605 
606 	if (usr_data) {
607 		ops.datbuf = memdup_user(usr_data, ops.len);
608 		if (IS_ERR(ops.datbuf))
609 			return PTR_ERR(ops.datbuf);
610 	} else {
611 		ops.datbuf = NULL;
612 	}
613 
614 	if (usr_oob) {
615 		ops.oobbuf = memdup_user(usr_oob, ops.ooblen);
616 		if (IS_ERR(ops.oobbuf)) {
617 			kfree(ops.datbuf);
618 			return PTR_ERR(ops.oobbuf);
619 		}
620 	} else {
621 		ops.oobbuf = NULL;
622 	}
623 
624 	ret = mtd_write_oob(mtd, (loff_t)req.start, &ops);
625 
626 	kfree(ops.datbuf);
627 	kfree(ops.oobbuf);
628 
629 	return ret;
630 }
631 
632 static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg)
633 {
634 	struct mtd_file_info *mfi = file->private_data;
635 	struct mtd_info *mtd = mfi->mtd;
636 	struct mtd_info *master = mtd_get_master(mtd);
637 	void __user *argp = (void __user *)arg;
638 	int ret = 0;
639 	struct mtd_info_user info;
640 
641 	pr_debug("MTD_ioctl\n");
642 
643 	/*
644 	 * Check the file mode to require "dangerous" commands to have write
645 	 * permissions.
646 	 */
647 	switch (cmd) {
648 	/* "safe" commands */
649 	case MEMGETREGIONCOUNT:
650 	case MEMGETREGIONINFO:
651 	case MEMGETINFO:
652 	case MEMREADOOB:
653 	case MEMREADOOB64:
654 	case MEMLOCK:
655 	case MEMUNLOCK:
656 	case MEMISLOCKED:
657 	case MEMGETOOBSEL:
658 	case MEMGETBADBLOCK:
659 	case MEMSETBADBLOCK:
660 	case OTPSELECT:
661 	case OTPGETREGIONCOUNT:
662 	case OTPGETREGIONINFO:
663 	case OTPLOCK:
664 	case ECCGETLAYOUT:
665 	case ECCGETSTATS:
666 	case MTDFILEMODE:
667 	case BLKPG:
668 	case BLKRRPART:
669 		break;
670 
671 	/* "dangerous" commands */
672 	case MEMERASE:
673 	case MEMERASE64:
674 	case MEMWRITEOOB:
675 	case MEMWRITEOOB64:
676 	case MEMWRITE:
677 		if (!(file->f_mode & FMODE_WRITE))
678 			return -EPERM;
679 		break;
680 
681 	default:
682 		return -ENOTTY;
683 	}
684 
685 	switch (cmd) {
686 	case MEMGETREGIONCOUNT:
687 		if (copy_to_user(argp, &(mtd->numeraseregions), sizeof(int)))
688 			return -EFAULT;
689 		break;
690 
691 	case MEMGETREGIONINFO:
692 	{
693 		uint32_t ur_idx;
694 		struct mtd_erase_region_info *kr;
695 		struct region_info_user __user *ur = argp;
696 
697 		if (get_user(ur_idx, &(ur->regionindex)))
698 			return -EFAULT;
699 
700 		if (ur_idx >= mtd->numeraseregions)
701 			return -EINVAL;
702 
703 		kr = &(mtd->eraseregions[ur_idx]);
704 
705 		if (put_user(kr->offset, &(ur->offset))
706 		    || put_user(kr->erasesize, &(ur->erasesize))
707 		    || put_user(kr->numblocks, &(ur->numblocks)))
708 			return -EFAULT;
709 
710 		break;
711 	}
712 
713 	case MEMGETINFO:
714 		memset(&info, 0, sizeof(info));
715 		info.type	= mtd->type;
716 		info.flags	= mtd->flags;
717 		info.size	= mtd->size;
718 		info.erasesize	= mtd->erasesize;
719 		info.writesize	= mtd->writesize;
720 		info.oobsize	= mtd->oobsize;
721 		/* The below field is obsolete */
722 		info.padding	= 0;
723 		if (copy_to_user(argp, &info, sizeof(struct mtd_info_user)))
724 			return -EFAULT;
725 		break;
726 
727 	case MEMERASE:
728 	case MEMERASE64:
729 	{
730 		struct erase_info *erase;
731 
732 		erase=kzalloc(sizeof(struct erase_info),GFP_KERNEL);
733 		if (!erase)
734 			ret = -ENOMEM;
735 		else {
736 			if (cmd == MEMERASE64) {
737 				struct erase_info_user64 einfo64;
738 
739 				if (copy_from_user(&einfo64, argp,
740 					    sizeof(struct erase_info_user64))) {
741 					kfree(erase);
742 					return -EFAULT;
743 				}
744 				erase->addr = einfo64.start;
745 				erase->len = einfo64.length;
746 			} else {
747 				struct erase_info_user einfo32;
748 
749 				if (copy_from_user(&einfo32, argp,
750 					    sizeof(struct erase_info_user))) {
751 					kfree(erase);
752 					return -EFAULT;
753 				}
754 				erase->addr = einfo32.start;
755 				erase->len = einfo32.length;
756 			}
757 
758 			ret = mtd_erase(mtd, erase);
759 			kfree(erase);
760 		}
761 		break;
762 	}
763 
764 	case MEMWRITEOOB:
765 	{
766 		struct mtd_oob_buf buf;
767 		struct mtd_oob_buf __user *buf_user = argp;
768 
769 		/* NOTE: writes return length to buf_user->length */
770 		if (copy_from_user(&buf, argp, sizeof(buf)))
771 			ret = -EFAULT;
772 		else
773 			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
774 				buf.ptr, &buf_user->length);
775 		break;
776 	}
777 
778 	case MEMREADOOB:
779 	{
780 		struct mtd_oob_buf buf;
781 		struct mtd_oob_buf __user *buf_user = argp;
782 
783 		/* NOTE: writes return length to buf_user->start */
784 		if (copy_from_user(&buf, argp, sizeof(buf)))
785 			ret = -EFAULT;
786 		else
787 			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
788 				buf.ptr, &buf_user->start);
789 		break;
790 	}
791 
792 	case MEMWRITEOOB64:
793 	{
794 		struct mtd_oob_buf64 buf;
795 		struct mtd_oob_buf64 __user *buf_user = argp;
796 
797 		if (copy_from_user(&buf, argp, sizeof(buf)))
798 			ret = -EFAULT;
799 		else
800 			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
801 				(void __user *)(uintptr_t)buf.usr_ptr,
802 				&buf_user->length);
803 		break;
804 	}
805 
806 	case MEMREADOOB64:
807 	{
808 		struct mtd_oob_buf64 buf;
809 		struct mtd_oob_buf64 __user *buf_user = argp;
810 
811 		if (copy_from_user(&buf, argp, sizeof(buf)))
812 			ret = -EFAULT;
813 		else
814 			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
815 				(void __user *)(uintptr_t)buf.usr_ptr,
816 				&buf_user->length);
817 		break;
818 	}
819 
820 	case MEMWRITE:
821 	{
822 		ret = mtdchar_write_ioctl(mtd,
823 		      (struct mtd_write_req __user *)arg);
824 		break;
825 	}
826 
827 	case MEMLOCK:
828 	{
829 		struct erase_info_user einfo;
830 
831 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
832 			return -EFAULT;
833 
834 		ret = mtd_lock(mtd, einfo.start, einfo.length);
835 		break;
836 	}
837 
838 	case MEMUNLOCK:
839 	{
840 		struct erase_info_user einfo;
841 
842 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
843 			return -EFAULT;
844 
845 		ret = mtd_unlock(mtd, einfo.start, einfo.length);
846 		break;
847 	}
848 
849 	case MEMISLOCKED:
850 	{
851 		struct erase_info_user einfo;
852 
853 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
854 			return -EFAULT;
855 
856 		ret = mtd_is_locked(mtd, einfo.start, einfo.length);
857 		break;
858 	}
859 
860 	/* Legacy interface */
861 	case MEMGETOOBSEL:
862 	{
863 		struct nand_oobinfo oi;
864 
865 		if (!master->ooblayout)
866 			return -EOPNOTSUPP;
867 
868 		ret = get_oobinfo(mtd, &oi);
869 		if (ret)
870 			return ret;
871 
872 		if (copy_to_user(argp, &oi, sizeof(struct nand_oobinfo)))
873 			return -EFAULT;
874 		break;
875 	}
876 
877 	case MEMGETBADBLOCK:
878 	{
879 		loff_t offs;
880 
881 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
882 			return -EFAULT;
883 		return mtd_block_isbad(mtd, offs);
884 		break;
885 	}
886 
887 	case MEMSETBADBLOCK:
888 	{
889 		loff_t offs;
890 
891 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
892 			return -EFAULT;
893 		return mtd_block_markbad(mtd, offs);
894 		break;
895 	}
896 
897 	case OTPSELECT:
898 	{
899 		int mode;
900 		if (copy_from_user(&mode, argp, sizeof(int)))
901 			return -EFAULT;
902 
903 		mfi->mode = MTD_FILE_MODE_NORMAL;
904 
905 		ret = otp_select_filemode(mfi, mode);
906 
907 		file->f_pos = 0;
908 		break;
909 	}
910 
911 	case OTPGETREGIONCOUNT:
912 	case OTPGETREGIONINFO:
913 	{
914 		struct otp_info *buf = kmalloc(4096, GFP_KERNEL);
915 		size_t retlen;
916 		if (!buf)
917 			return -ENOMEM;
918 		switch (mfi->mode) {
919 		case MTD_FILE_MODE_OTP_FACTORY:
920 			ret = mtd_get_fact_prot_info(mtd, 4096, &retlen, buf);
921 			break;
922 		case MTD_FILE_MODE_OTP_USER:
923 			ret = mtd_get_user_prot_info(mtd, 4096, &retlen, buf);
924 			break;
925 		default:
926 			ret = -EINVAL;
927 			break;
928 		}
929 		if (!ret) {
930 			if (cmd == OTPGETREGIONCOUNT) {
931 				int nbr = retlen / sizeof(struct otp_info);
932 				ret = copy_to_user(argp, &nbr, sizeof(int));
933 			} else
934 				ret = copy_to_user(argp, buf, retlen);
935 			if (ret)
936 				ret = -EFAULT;
937 		}
938 		kfree(buf);
939 		break;
940 	}
941 
942 	case OTPLOCK:
943 	{
944 		struct otp_info oinfo;
945 
946 		if (mfi->mode != MTD_FILE_MODE_OTP_USER)
947 			return -EINVAL;
948 		if (copy_from_user(&oinfo, argp, sizeof(oinfo)))
949 			return -EFAULT;
950 		ret = mtd_lock_user_prot_reg(mtd, oinfo.start, oinfo.length);
951 		break;
952 	}
953 
954 	/* This ioctl is being deprecated - it truncates the ECC layout */
955 	case ECCGETLAYOUT:
956 	{
957 		struct nand_ecclayout_user *usrlay;
958 
959 		if (!master->ooblayout)
960 			return -EOPNOTSUPP;
961 
962 		usrlay = kmalloc(sizeof(*usrlay), GFP_KERNEL);
963 		if (!usrlay)
964 			return -ENOMEM;
965 
966 		shrink_ecclayout(mtd, usrlay);
967 
968 		if (copy_to_user(argp, usrlay, sizeof(*usrlay)))
969 			ret = -EFAULT;
970 		kfree(usrlay);
971 		break;
972 	}
973 
974 	case ECCGETSTATS:
975 	{
976 		if (copy_to_user(argp, &mtd->ecc_stats,
977 				 sizeof(struct mtd_ecc_stats)))
978 			return -EFAULT;
979 		break;
980 	}
981 
982 	case MTDFILEMODE:
983 	{
984 		mfi->mode = 0;
985 
986 		switch(arg) {
987 		case MTD_FILE_MODE_OTP_FACTORY:
988 		case MTD_FILE_MODE_OTP_USER:
989 			ret = otp_select_filemode(mfi, arg);
990 			break;
991 
992 		case MTD_FILE_MODE_RAW:
993 			if (!mtd_has_oob(mtd))
994 				return -EOPNOTSUPP;
995 			mfi->mode = arg;
996 
997 		case MTD_FILE_MODE_NORMAL:
998 			break;
999 		default:
1000 			ret = -EINVAL;
1001 		}
1002 		file->f_pos = 0;
1003 		break;
1004 	}
1005 
1006 	case BLKPG:
1007 	{
1008 		struct blkpg_ioctl_arg __user *blk_arg = argp;
1009 		struct blkpg_ioctl_arg a;
1010 
1011 		if (copy_from_user(&a, blk_arg, sizeof(a)))
1012 			ret = -EFAULT;
1013 		else
1014 			ret = mtdchar_blkpg_ioctl(mtd, &a);
1015 		break;
1016 	}
1017 
1018 	case BLKRRPART:
1019 	{
1020 		/* No reread partition feature. Just return ok */
1021 		ret = 0;
1022 		break;
1023 	}
1024 	}
1025 
1026 	return ret;
1027 } /* memory_ioctl */
1028 
1029 static long mtdchar_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
1030 {
1031 	int ret;
1032 
1033 	mutex_lock(&mtd_mutex);
1034 	ret = mtdchar_ioctl(file, cmd, arg);
1035 	mutex_unlock(&mtd_mutex);
1036 
1037 	return ret;
1038 }
1039 
1040 #ifdef CONFIG_COMPAT
1041 
1042 struct mtd_oob_buf32 {
1043 	u_int32_t start;
1044 	u_int32_t length;
1045 	compat_caddr_t ptr;	/* unsigned char* */
1046 };
1047 
1048 #define MEMWRITEOOB32		_IOWR('M', 3, struct mtd_oob_buf32)
1049 #define MEMREADOOB32		_IOWR('M', 4, struct mtd_oob_buf32)
1050 
1051 static long mtdchar_compat_ioctl(struct file *file, unsigned int cmd,
1052 	unsigned long arg)
1053 {
1054 	struct mtd_file_info *mfi = file->private_data;
1055 	struct mtd_info *mtd = mfi->mtd;
1056 	void __user *argp = compat_ptr(arg);
1057 	int ret = 0;
1058 
1059 	mutex_lock(&mtd_mutex);
1060 
1061 	switch (cmd) {
1062 	case MEMWRITEOOB32:
1063 	{
1064 		struct mtd_oob_buf32 buf;
1065 		struct mtd_oob_buf32 __user *buf_user = argp;
1066 
1067 		if (!(file->f_mode & FMODE_WRITE)) {
1068 			ret = -EPERM;
1069 			break;
1070 		}
1071 
1072 		if (copy_from_user(&buf, argp, sizeof(buf)))
1073 			ret = -EFAULT;
1074 		else
1075 			ret = mtdchar_writeoob(file, mtd, buf.start,
1076 				buf.length, compat_ptr(buf.ptr),
1077 				&buf_user->length);
1078 		break;
1079 	}
1080 
1081 	case MEMREADOOB32:
1082 	{
1083 		struct mtd_oob_buf32 buf;
1084 		struct mtd_oob_buf32 __user *buf_user = argp;
1085 
1086 		/* NOTE: writes return length to buf->start */
1087 		if (copy_from_user(&buf, argp, sizeof(buf)))
1088 			ret = -EFAULT;
1089 		else
1090 			ret = mtdchar_readoob(file, mtd, buf.start,
1091 				buf.length, compat_ptr(buf.ptr),
1092 				&buf_user->start);
1093 		break;
1094 	}
1095 
1096 	case BLKPG:
1097 	{
1098 		/* Convert from blkpg_compat_ioctl_arg to blkpg_ioctl_arg */
1099 		struct blkpg_compat_ioctl_arg __user *uarg = argp;
1100 		struct blkpg_compat_ioctl_arg compat_arg;
1101 		struct blkpg_ioctl_arg a;
1102 
1103 		if (copy_from_user(&compat_arg, uarg, sizeof(compat_arg))) {
1104 			ret = -EFAULT;
1105 			break;
1106 		}
1107 
1108 		memset(&a, 0, sizeof(a));
1109 		a.op = compat_arg.op;
1110 		a.flags = compat_arg.flags;
1111 		a.datalen = compat_arg.datalen;
1112 		a.data = compat_ptr(compat_arg.data);
1113 
1114 		ret = mtdchar_blkpg_ioctl(mtd, &a);
1115 		break;
1116 	}
1117 
1118 	default:
1119 		ret = mtdchar_ioctl(file, cmd, (unsigned long)argp);
1120 	}
1121 
1122 	mutex_unlock(&mtd_mutex);
1123 
1124 	return ret;
1125 }
1126 
1127 #endif /* CONFIG_COMPAT */
1128 
1129 /*
1130  * try to determine where a shared mapping can be made
1131  * - only supported for NOMMU at the moment (MMU can't doesn't copy private
1132  *   mappings)
1133  */
1134 #ifndef CONFIG_MMU
1135 static unsigned long mtdchar_get_unmapped_area(struct file *file,
1136 					   unsigned long addr,
1137 					   unsigned long len,
1138 					   unsigned long pgoff,
1139 					   unsigned long flags)
1140 {
1141 	struct mtd_file_info *mfi = file->private_data;
1142 	struct mtd_info *mtd = mfi->mtd;
1143 	unsigned long offset;
1144 	int ret;
1145 
1146 	if (addr != 0)
1147 		return (unsigned long) -EINVAL;
1148 
1149 	if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT))
1150 		return (unsigned long) -EINVAL;
1151 
1152 	offset = pgoff << PAGE_SHIFT;
1153 	if (offset > mtd->size - len)
1154 		return (unsigned long) -EINVAL;
1155 
1156 	ret = mtd_get_unmapped_area(mtd, len, offset, flags);
1157 	return ret == -EOPNOTSUPP ? -ENODEV : ret;
1158 }
1159 
1160 static unsigned mtdchar_mmap_capabilities(struct file *file)
1161 {
1162 	struct mtd_file_info *mfi = file->private_data;
1163 
1164 	return mtd_mmap_capabilities(mfi->mtd);
1165 }
1166 #endif
1167 
1168 /*
1169  * set up a mapping for shared memory segments
1170  */
1171 static int mtdchar_mmap(struct file *file, struct vm_area_struct *vma)
1172 {
1173 #ifdef CONFIG_MMU
1174 	struct mtd_file_info *mfi = file->private_data;
1175 	struct mtd_info *mtd = mfi->mtd;
1176 	struct map_info *map = mtd->priv;
1177 
1178         /* This is broken because it assumes the MTD device is map-based
1179 	   and that mtd->priv is a valid struct map_info.  It should be
1180 	   replaced with something that uses the mtd_get_unmapped_area()
1181 	   operation properly. */
1182 	if (0 /*mtd->type == MTD_RAM || mtd->type == MTD_ROM*/) {
1183 #ifdef pgprot_noncached
1184 		if (file->f_flags & O_DSYNC || map->phys >= __pa(high_memory))
1185 			vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1186 #endif
1187 		return vm_iomap_memory(vma, map->phys, map->size);
1188 	}
1189 	return -ENODEV;
1190 #else
1191 	return vma->vm_flags & VM_SHARED ? 0 : -EACCES;
1192 #endif
1193 }
1194 
1195 static const struct file_operations mtd_fops = {
1196 	.owner		= THIS_MODULE,
1197 	.llseek		= mtdchar_lseek,
1198 	.read		= mtdchar_read,
1199 	.write		= mtdchar_write,
1200 	.unlocked_ioctl	= mtdchar_unlocked_ioctl,
1201 #ifdef CONFIG_COMPAT
1202 	.compat_ioctl	= mtdchar_compat_ioctl,
1203 #endif
1204 	.open		= mtdchar_open,
1205 	.release	= mtdchar_close,
1206 	.mmap		= mtdchar_mmap,
1207 #ifndef CONFIG_MMU
1208 	.get_unmapped_area = mtdchar_get_unmapped_area,
1209 	.mmap_capabilities = mtdchar_mmap_capabilities,
1210 #endif
1211 };
1212 
1213 int __init init_mtdchar(void)
1214 {
1215 	int ret;
1216 
1217 	ret = __register_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS,
1218 				   "mtd", &mtd_fops);
1219 	if (ret < 0) {
1220 		pr_err("Can't allocate major number %d for MTD\n",
1221 		       MTD_CHAR_MAJOR);
1222 		return ret;
1223 	}
1224 
1225 	return ret;
1226 }
1227 
1228 void __exit cleanup_mtdchar(void)
1229 {
1230 	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1231 }
1232 
1233 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);
1234