xref: /linux/drivers/mtd/mtdchar.c (revision cd621274b0ec747db8dedbf857624c067f481976)
1 /*
2  * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17  *
18  */
19 
20 #include <linux/device.h>
21 #include <linux/fs.h>
22 #include <linux/mm.h>
23 #include <linux/err.h>
24 #include <linux/init.h>
25 #include <linux/kernel.h>
26 #include <linux/module.h>
27 #include <linux/slab.h>
28 #include <linux/sched.h>
29 #include <linux/mutex.h>
30 #include <linux/backing-dev.h>
31 #include <linux/compat.h>
32 #include <linux/mount.h>
33 #include <linux/blkpg.h>
34 #include <linux/mtd/mtd.h>
35 #include <linux/mtd/partitions.h>
36 #include <linux/mtd/map.h>
37 
38 #include <asm/uaccess.h>
39 
40 #define MTD_INODE_FS_MAGIC 0x11307854
41 static DEFINE_MUTEX(mtd_mutex);
42 static struct vfsmount *mtd_inode_mnt __read_mostly;
43 
44 /*
45  * Data structure to hold the pointer to the mtd device as well
46  * as mode information of various use cases.
47  */
48 struct mtd_file_info {
49 	struct mtd_info *mtd;
50 	struct inode *ino;
51 	enum mtd_file_modes mode;
52 };
53 
54 static loff_t mtdchar_lseek(struct file *file, loff_t offset, int orig)
55 {
56 	struct mtd_file_info *mfi = file->private_data;
57 	struct mtd_info *mtd = mfi->mtd;
58 
59 	switch (orig) {
60 	case SEEK_SET:
61 		break;
62 	case SEEK_CUR:
63 		offset += file->f_pos;
64 		break;
65 	case SEEK_END:
66 		offset += mtd->size;
67 		break;
68 	default:
69 		return -EINVAL;
70 	}
71 
72 	if (offset >= 0 && offset <= mtd->size)
73 		return file->f_pos = offset;
74 
75 	return -EINVAL;
76 }
77 
78 
79 
80 static int mtdchar_open(struct inode *inode, struct file *file)
81 {
82 	int minor = iminor(inode);
83 	int devnum = minor >> 1;
84 	int ret = 0;
85 	struct mtd_info *mtd;
86 	struct mtd_file_info *mfi;
87 	struct inode *mtd_ino;
88 
89 	pr_debug("MTD_open\n");
90 
91 	/* You can't open the RO devices RW */
92 	if ((file->f_mode & FMODE_WRITE) && (minor & 1))
93 		return -EACCES;
94 
95 	mutex_lock(&mtd_mutex);
96 	mtd = get_mtd_device(NULL, devnum);
97 
98 	if (IS_ERR(mtd)) {
99 		ret = PTR_ERR(mtd);
100 		goto out;
101 	}
102 
103 	if (mtd->type == MTD_ABSENT) {
104 		put_mtd_device(mtd);
105 		ret = -ENODEV;
106 		goto out;
107 	}
108 
109 	mtd_ino = iget_locked(mtd_inode_mnt->mnt_sb, devnum);
110 	if (!mtd_ino) {
111 		put_mtd_device(mtd);
112 		ret = -ENOMEM;
113 		goto out;
114 	}
115 	if (mtd_ino->i_state & I_NEW) {
116 		mtd_ino->i_private = mtd;
117 		mtd_ino->i_mode = S_IFCHR;
118 		mtd_ino->i_data.backing_dev_info = mtd->backing_dev_info;
119 		unlock_new_inode(mtd_ino);
120 	}
121 	file->f_mapping = mtd_ino->i_mapping;
122 
123 	/* You can't open it RW if it's not a writeable device */
124 	if ((file->f_mode & FMODE_WRITE) && !(mtd->flags & MTD_WRITEABLE)) {
125 		iput(mtd_ino);
126 		put_mtd_device(mtd);
127 		ret = -EACCES;
128 		goto out;
129 	}
130 
131 	mfi = kzalloc(sizeof(*mfi), GFP_KERNEL);
132 	if (!mfi) {
133 		iput(mtd_ino);
134 		put_mtd_device(mtd);
135 		ret = -ENOMEM;
136 		goto out;
137 	}
138 	mfi->ino = mtd_ino;
139 	mfi->mtd = mtd;
140 	file->private_data = mfi;
141 
142 out:
143 	mutex_unlock(&mtd_mutex);
144 	return ret;
145 } /* mtdchar_open */
146 
147 /*====================================================================*/
148 
149 static int mtdchar_close(struct inode *inode, struct file *file)
150 {
151 	struct mtd_file_info *mfi = file->private_data;
152 	struct mtd_info *mtd = mfi->mtd;
153 
154 	pr_debug("MTD_close\n");
155 
156 	/* Only sync if opened RW */
157 	if ((file->f_mode & FMODE_WRITE) && mtd->sync)
158 		mtd_sync(mtd);
159 
160 	iput(mfi->ino);
161 
162 	put_mtd_device(mtd);
163 	file->private_data = NULL;
164 	kfree(mfi);
165 
166 	return 0;
167 } /* mtdchar_close */
168 
169 /* Back in June 2001, dwmw2 wrote:
170  *
171  *   FIXME: This _really_ needs to die. In 2.5, we should lock the
172  *   userspace buffer down and use it directly with readv/writev.
173  *
174  * The implementation below, using mtd_kmalloc_up_to, mitigates
175  * allocation failures when the system is under low-memory situations
176  * or if memory is highly fragmented at the cost of reducing the
177  * performance of the requested transfer due to a smaller buffer size.
178  *
179  * A more complex but more memory-efficient implementation based on
180  * get_user_pages and iovecs to cover extents of those pages is a
181  * longer-term goal, as intimated by dwmw2 above. However, for the
182  * write case, this requires yet more complex head and tail transfer
183  * handling when those head and tail offsets and sizes are such that
184  * alignment requirements are not met in the NAND subdriver.
185  */
186 
187 static ssize_t mtdchar_read(struct file *file, char __user *buf, size_t count,
188 			loff_t *ppos)
189 {
190 	struct mtd_file_info *mfi = file->private_data;
191 	struct mtd_info *mtd = mfi->mtd;
192 	size_t retlen;
193 	size_t total_retlen=0;
194 	int ret=0;
195 	int len;
196 	size_t size = count;
197 	char *kbuf;
198 
199 	pr_debug("MTD_read\n");
200 
201 	if (*ppos + count > mtd->size)
202 		count = mtd->size - *ppos;
203 
204 	if (!count)
205 		return 0;
206 
207 	kbuf = mtd_kmalloc_up_to(mtd, &size);
208 	if (!kbuf)
209 		return -ENOMEM;
210 
211 	while (count) {
212 		len = min_t(size_t, count, size);
213 
214 		switch (mfi->mode) {
215 		case MTD_FILE_MODE_OTP_FACTORY:
216 			ret = mtd_read_fact_prot_reg(mtd, *ppos, len,
217 						     &retlen, kbuf);
218 			break;
219 		case MTD_FILE_MODE_OTP_USER:
220 			ret = mtd_read_user_prot_reg(mtd, *ppos, len,
221 						     &retlen, kbuf);
222 			break;
223 		case MTD_FILE_MODE_RAW:
224 		{
225 			struct mtd_oob_ops ops;
226 
227 			ops.mode = MTD_OPS_RAW;
228 			ops.datbuf = kbuf;
229 			ops.oobbuf = NULL;
230 			ops.len = len;
231 
232 			ret = mtd_read_oob(mtd, *ppos, &ops);
233 			retlen = ops.retlen;
234 			break;
235 		}
236 		default:
237 			ret = mtd_read(mtd, *ppos, len, &retlen, kbuf);
238 		}
239 		/* Nand returns -EBADMSG on ECC errors, but it returns
240 		 * the data. For our userspace tools it is important
241 		 * to dump areas with ECC errors!
242 		 * For kernel internal usage it also might return -EUCLEAN
243 		 * to signal the caller that a bitflip has occurred and has
244 		 * been corrected by the ECC algorithm.
245 		 * Userspace software which accesses NAND this way
246 		 * must be aware of the fact that it deals with NAND
247 		 */
248 		if (!ret || mtd_is_bitflip_or_eccerr(ret)) {
249 			*ppos += retlen;
250 			if (copy_to_user(buf, kbuf, retlen)) {
251 				kfree(kbuf);
252 				return -EFAULT;
253 			}
254 			else
255 				total_retlen += retlen;
256 
257 			count -= retlen;
258 			buf += retlen;
259 			if (retlen == 0)
260 				count = 0;
261 		}
262 		else {
263 			kfree(kbuf);
264 			return ret;
265 		}
266 
267 	}
268 
269 	kfree(kbuf);
270 	return total_retlen;
271 } /* mtdchar_read */
272 
273 static ssize_t mtdchar_write(struct file *file, const char __user *buf, size_t count,
274 			loff_t *ppos)
275 {
276 	struct mtd_file_info *mfi = file->private_data;
277 	struct mtd_info *mtd = mfi->mtd;
278 	size_t size = count;
279 	char *kbuf;
280 	size_t retlen;
281 	size_t total_retlen=0;
282 	int ret=0;
283 	int len;
284 
285 	pr_debug("MTD_write\n");
286 
287 	if (*ppos == mtd->size)
288 		return -ENOSPC;
289 
290 	if (*ppos + count > mtd->size)
291 		count = mtd->size - *ppos;
292 
293 	if (!count)
294 		return 0;
295 
296 	kbuf = mtd_kmalloc_up_to(mtd, &size);
297 	if (!kbuf)
298 		return -ENOMEM;
299 
300 	while (count) {
301 		len = min_t(size_t, count, size);
302 
303 		if (copy_from_user(kbuf, buf, len)) {
304 			kfree(kbuf);
305 			return -EFAULT;
306 		}
307 
308 		switch (mfi->mode) {
309 		case MTD_FILE_MODE_OTP_FACTORY:
310 			ret = -EROFS;
311 			break;
312 		case MTD_FILE_MODE_OTP_USER:
313 			if (!mtd->write_user_prot_reg) {
314 				ret = -EOPNOTSUPP;
315 				break;
316 			}
317 			ret = mtd_write_user_prot_reg(mtd, *ppos, len,
318 						      &retlen, kbuf);
319 			break;
320 
321 		case MTD_FILE_MODE_RAW:
322 		{
323 			struct mtd_oob_ops ops;
324 
325 			ops.mode = MTD_OPS_RAW;
326 			ops.datbuf = kbuf;
327 			ops.oobbuf = NULL;
328 			ops.ooboffs = 0;
329 			ops.len = len;
330 
331 			ret = mtd_write_oob(mtd, *ppos, &ops);
332 			retlen = ops.retlen;
333 			break;
334 		}
335 
336 		default:
337 			ret = mtd_write(mtd, *ppos, len, &retlen, kbuf);
338 		}
339 		if (!ret) {
340 			*ppos += retlen;
341 			total_retlen += retlen;
342 			count -= retlen;
343 			buf += retlen;
344 		}
345 		else {
346 			kfree(kbuf);
347 			return ret;
348 		}
349 	}
350 
351 	kfree(kbuf);
352 	return total_retlen;
353 } /* mtdchar_write */
354 
355 /*======================================================================
356 
357     IOCTL calls for getting device parameters.
358 
359 ======================================================================*/
360 static void mtdchar_erase_callback (struct erase_info *instr)
361 {
362 	wake_up((wait_queue_head_t *)instr->priv);
363 }
364 
365 #ifdef CONFIG_HAVE_MTD_OTP
366 static int otp_select_filemode(struct mtd_file_info *mfi, int mode)
367 {
368 	struct mtd_info *mtd = mfi->mtd;
369 	int ret = 0;
370 
371 	switch (mode) {
372 	case MTD_OTP_FACTORY:
373 		if (!mtd->read_fact_prot_reg)
374 			ret = -EOPNOTSUPP;
375 		else
376 			mfi->mode = MTD_FILE_MODE_OTP_FACTORY;
377 		break;
378 	case MTD_OTP_USER:
379 		if (!mtd->read_fact_prot_reg)
380 			ret = -EOPNOTSUPP;
381 		else
382 			mfi->mode = MTD_FILE_MODE_OTP_USER;
383 		break;
384 	default:
385 		ret = -EINVAL;
386 	case MTD_OTP_OFF:
387 		break;
388 	}
389 	return ret;
390 }
391 #else
392 # define otp_select_filemode(f,m)	-EOPNOTSUPP
393 #endif
394 
395 static int mtdchar_writeoob(struct file *file, struct mtd_info *mtd,
396 	uint64_t start, uint32_t length, void __user *ptr,
397 	uint32_t __user *retp)
398 {
399 	struct mtd_file_info *mfi = file->private_data;
400 	struct mtd_oob_ops ops;
401 	uint32_t retlen;
402 	int ret = 0;
403 
404 	if (!(file->f_mode & FMODE_WRITE))
405 		return -EPERM;
406 
407 	if (length > 4096)
408 		return -EINVAL;
409 
410 	if (!mtd->write_oob)
411 		ret = -EOPNOTSUPP;
412 	else
413 		ret = access_ok(VERIFY_READ, ptr, length) ? 0 : -EFAULT;
414 
415 	if (ret)
416 		return ret;
417 
418 	ops.ooblen = length;
419 	ops.ooboffs = start & (mtd->writesize - 1);
420 	ops.datbuf = NULL;
421 	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
422 		MTD_OPS_PLACE_OOB;
423 
424 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
425 		return -EINVAL;
426 
427 	ops.oobbuf = memdup_user(ptr, length);
428 	if (IS_ERR(ops.oobbuf))
429 		return PTR_ERR(ops.oobbuf);
430 
431 	start &= ~((uint64_t)mtd->writesize - 1);
432 	ret = mtd_write_oob(mtd, start, &ops);
433 
434 	if (ops.oobretlen > 0xFFFFFFFFU)
435 		ret = -EOVERFLOW;
436 	retlen = ops.oobretlen;
437 	if (copy_to_user(retp, &retlen, sizeof(length)))
438 		ret = -EFAULT;
439 
440 	kfree(ops.oobbuf);
441 	return ret;
442 }
443 
444 static int mtdchar_readoob(struct file *file, struct mtd_info *mtd,
445 	uint64_t start, uint32_t length, void __user *ptr,
446 	uint32_t __user *retp)
447 {
448 	struct mtd_file_info *mfi = file->private_data;
449 	struct mtd_oob_ops ops;
450 	int ret = 0;
451 
452 	if (length > 4096)
453 		return -EINVAL;
454 
455 	if (!mtd->read_oob)
456 		ret = -EOPNOTSUPP;
457 	else
458 		ret = access_ok(VERIFY_WRITE, ptr,
459 				length) ? 0 : -EFAULT;
460 	if (ret)
461 		return ret;
462 
463 	ops.ooblen = length;
464 	ops.ooboffs = start & (mtd->writesize - 1);
465 	ops.datbuf = NULL;
466 	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
467 		MTD_OPS_PLACE_OOB;
468 
469 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
470 		return -EINVAL;
471 
472 	ops.oobbuf = kmalloc(length, GFP_KERNEL);
473 	if (!ops.oobbuf)
474 		return -ENOMEM;
475 
476 	start &= ~((uint64_t)mtd->writesize - 1);
477 	ret = mtd_read_oob(mtd, start, &ops);
478 
479 	if (put_user(ops.oobretlen, retp))
480 		ret = -EFAULT;
481 	else if (ops.oobretlen && copy_to_user(ptr, ops.oobbuf,
482 					    ops.oobretlen))
483 		ret = -EFAULT;
484 
485 	kfree(ops.oobbuf);
486 
487 	/*
488 	 * NAND returns -EBADMSG on ECC errors, but it returns the OOB
489 	 * data. For our userspace tools it is important to dump areas
490 	 * with ECC errors!
491 	 * For kernel internal usage it also might return -EUCLEAN
492 	 * to signal the caller that a bitflip has occured and has
493 	 * been corrected by the ECC algorithm.
494 	 *
495 	 * Note: currently the standard NAND function, nand_read_oob_std,
496 	 * does not calculate ECC for the OOB area, so do not rely on
497 	 * this behavior unless you have replaced it with your own.
498 	 */
499 	if (mtd_is_bitflip_or_eccerr(ret))
500 		return 0;
501 
502 	return ret;
503 }
504 
505 /*
506  * Copies (and truncates, if necessary) data from the larger struct,
507  * nand_ecclayout, to the smaller, deprecated layout struct,
508  * nand_ecclayout_user. This is necessary only to support the deprecated
509  * API ioctl ECCGETLAYOUT while allowing all new functionality to use
510  * nand_ecclayout flexibly (i.e. the struct may change size in new
511  * releases without requiring major rewrites).
512  */
513 static int shrink_ecclayout(const struct nand_ecclayout *from,
514 		struct nand_ecclayout_user *to)
515 {
516 	int i;
517 
518 	if (!from || !to)
519 		return -EINVAL;
520 
521 	memset(to, 0, sizeof(*to));
522 
523 	to->eccbytes = min((int)from->eccbytes, MTD_MAX_ECCPOS_ENTRIES);
524 	for (i = 0; i < to->eccbytes; i++)
525 		to->eccpos[i] = from->eccpos[i];
526 
527 	for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES; i++) {
528 		if (from->oobfree[i].length == 0 &&
529 				from->oobfree[i].offset == 0)
530 			break;
531 		to->oobavail += from->oobfree[i].length;
532 		to->oobfree[i] = from->oobfree[i];
533 	}
534 
535 	return 0;
536 }
537 
538 static int mtdchar_blkpg_ioctl(struct mtd_info *mtd,
539 			   struct blkpg_ioctl_arg __user *arg)
540 {
541 	struct blkpg_ioctl_arg a;
542 	struct blkpg_partition p;
543 
544 	if (!capable(CAP_SYS_ADMIN))
545 		return -EPERM;
546 
547 	if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
548 		return -EFAULT;
549 
550 	if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
551 		return -EFAULT;
552 
553 	switch (a.op) {
554 	case BLKPG_ADD_PARTITION:
555 
556 		/* Only master mtd device must be used to add partitions */
557 		if (mtd_is_partition(mtd))
558 			return -EINVAL;
559 
560 		return mtd_add_partition(mtd, p.devname, p.start, p.length);
561 
562 	case BLKPG_DEL_PARTITION:
563 
564 		if (p.pno < 0)
565 			return -EINVAL;
566 
567 		return mtd_del_partition(mtd, p.pno);
568 
569 	default:
570 		return -EINVAL;
571 	}
572 }
573 
574 static int mtdchar_write_ioctl(struct mtd_info *mtd,
575 		struct mtd_write_req __user *argp)
576 {
577 	struct mtd_write_req req;
578 	struct mtd_oob_ops ops;
579 	void __user *usr_data, *usr_oob;
580 	int ret;
581 
582 	if (copy_from_user(&req, argp, sizeof(req)) ||
583 			!access_ok(VERIFY_READ, req.usr_data, req.len) ||
584 			!access_ok(VERIFY_READ, req.usr_oob, req.ooblen))
585 		return -EFAULT;
586 	if (!mtd->write_oob)
587 		return -EOPNOTSUPP;
588 
589 	ops.mode = req.mode;
590 	ops.len = (size_t)req.len;
591 	ops.ooblen = (size_t)req.ooblen;
592 	ops.ooboffs = 0;
593 
594 	usr_data = (void __user *)(uintptr_t)req.usr_data;
595 	usr_oob = (void __user *)(uintptr_t)req.usr_oob;
596 
597 	if (req.usr_data) {
598 		ops.datbuf = memdup_user(usr_data, ops.len);
599 		if (IS_ERR(ops.datbuf))
600 			return PTR_ERR(ops.datbuf);
601 	} else {
602 		ops.datbuf = NULL;
603 	}
604 
605 	if (req.usr_oob) {
606 		ops.oobbuf = memdup_user(usr_oob, ops.ooblen);
607 		if (IS_ERR(ops.oobbuf)) {
608 			kfree(ops.datbuf);
609 			return PTR_ERR(ops.oobbuf);
610 		}
611 	} else {
612 		ops.oobbuf = NULL;
613 	}
614 
615 	ret = mtd_write_oob(mtd, (loff_t)req.start, &ops);
616 
617 	kfree(ops.datbuf);
618 	kfree(ops.oobbuf);
619 
620 	return ret;
621 }
622 
623 static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg)
624 {
625 	struct mtd_file_info *mfi = file->private_data;
626 	struct mtd_info *mtd = mfi->mtd;
627 	void __user *argp = (void __user *)arg;
628 	int ret = 0;
629 	u_long size;
630 	struct mtd_info_user info;
631 
632 	pr_debug("MTD_ioctl\n");
633 
634 	size = (cmd & IOCSIZE_MASK) >> IOCSIZE_SHIFT;
635 	if (cmd & IOC_IN) {
636 		if (!access_ok(VERIFY_READ, argp, size))
637 			return -EFAULT;
638 	}
639 	if (cmd & IOC_OUT) {
640 		if (!access_ok(VERIFY_WRITE, argp, size))
641 			return -EFAULT;
642 	}
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 			wait_queue_head_t waitq;
699 			DECLARE_WAITQUEUE(wait, current);
700 
701 			init_waitqueue_head(&waitq);
702 
703 			if (cmd == MEMERASE64) {
704 				struct erase_info_user64 einfo64;
705 
706 				if (copy_from_user(&einfo64, argp,
707 					    sizeof(struct erase_info_user64))) {
708 					kfree(erase);
709 					return -EFAULT;
710 				}
711 				erase->addr = einfo64.start;
712 				erase->len = einfo64.length;
713 			} else {
714 				struct erase_info_user einfo32;
715 
716 				if (copy_from_user(&einfo32, argp,
717 					    sizeof(struct erase_info_user))) {
718 					kfree(erase);
719 					return -EFAULT;
720 				}
721 				erase->addr = einfo32.start;
722 				erase->len = einfo32.length;
723 			}
724 			erase->mtd = mtd;
725 			erase->callback = mtdchar_erase_callback;
726 			erase->priv = (unsigned long)&waitq;
727 
728 			/*
729 			  FIXME: Allow INTERRUPTIBLE. Which means
730 			  not having the wait_queue head on the stack.
731 
732 			  If the wq_head is on the stack, and we
733 			  leave because we got interrupted, then the
734 			  wq_head is no longer there when the
735 			  callback routine tries to wake us up.
736 			*/
737 			ret = mtd_erase(mtd, erase);
738 			if (!ret) {
739 				set_current_state(TASK_UNINTERRUPTIBLE);
740 				add_wait_queue(&waitq, &wait);
741 				if (erase->state != MTD_ERASE_DONE &&
742 				    erase->state != MTD_ERASE_FAILED)
743 					schedule();
744 				remove_wait_queue(&waitq, &wait);
745 				set_current_state(TASK_RUNNING);
746 
747 				ret = (erase->state == MTD_ERASE_FAILED)?-EIO:0;
748 			}
749 			kfree(erase);
750 		}
751 		break;
752 	}
753 
754 	case MEMWRITEOOB:
755 	{
756 		struct mtd_oob_buf buf;
757 		struct mtd_oob_buf __user *buf_user = argp;
758 
759 		/* NOTE: writes return length to buf_user->length */
760 		if (copy_from_user(&buf, argp, sizeof(buf)))
761 			ret = -EFAULT;
762 		else
763 			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
764 				buf.ptr, &buf_user->length);
765 		break;
766 	}
767 
768 	case MEMREADOOB:
769 	{
770 		struct mtd_oob_buf buf;
771 		struct mtd_oob_buf __user *buf_user = argp;
772 
773 		/* NOTE: writes return length to buf_user->start */
774 		if (copy_from_user(&buf, argp, sizeof(buf)))
775 			ret = -EFAULT;
776 		else
777 			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
778 				buf.ptr, &buf_user->start);
779 		break;
780 	}
781 
782 	case MEMWRITEOOB64:
783 	{
784 		struct mtd_oob_buf64 buf;
785 		struct mtd_oob_buf64 __user *buf_user = argp;
786 
787 		if (copy_from_user(&buf, argp, sizeof(buf)))
788 			ret = -EFAULT;
789 		else
790 			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
791 				(void __user *)(uintptr_t)buf.usr_ptr,
792 				&buf_user->length);
793 		break;
794 	}
795 
796 	case MEMREADOOB64:
797 	{
798 		struct mtd_oob_buf64 buf;
799 		struct mtd_oob_buf64 __user *buf_user = argp;
800 
801 		if (copy_from_user(&buf, argp, sizeof(buf)))
802 			ret = -EFAULT;
803 		else
804 			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
805 				(void __user *)(uintptr_t)buf.usr_ptr,
806 				&buf_user->length);
807 		break;
808 	}
809 
810 	case MEMWRITE:
811 	{
812 		ret = mtdchar_write_ioctl(mtd,
813 		      (struct mtd_write_req __user *)arg);
814 		break;
815 	}
816 
817 	case MEMLOCK:
818 	{
819 		struct erase_info_user einfo;
820 
821 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
822 			return -EFAULT;
823 
824 		if (!mtd->lock)
825 			ret = -EOPNOTSUPP;
826 		else
827 			ret = mtd_lock(mtd, einfo.start, einfo.length);
828 		break;
829 	}
830 
831 	case MEMUNLOCK:
832 	{
833 		struct erase_info_user einfo;
834 
835 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
836 			return -EFAULT;
837 
838 		if (!mtd->unlock)
839 			ret = -EOPNOTSUPP;
840 		else
841 			ret = mtd_unlock(mtd, einfo.start, einfo.length);
842 		break;
843 	}
844 
845 	case MEMISLOCKED:
846 	{
847 		struct erase_info_user einfo;
848 
849 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
850 			return -EFAULT;
851 
852 		if (!mtd->is_locked)
853 			ret = -EOPNOTSUPP;
854 		else
855 			ret = mtd_is_locked(mtd, einfo.start, einfo.length);
856 		break;
857 	}
858 
859 	/* Legacy interface */
860 	case MEMGETOOBSEL:
861 	{
862 		struct nand_oobinfo oi;
863 
864 		if (!mtd->ecclayout)
865 			return -EOPNOTSUPP;
866 		if (mtd->ecclayout->eccbytes > ARRAY_SIZE(oi.eccpos))
867 			return -EINVAL;
868 
869 		oi.useecc = MTD_NANDECC_AUTOPLACE;
870 		memcpy(&oi.eccpos, mtd->ecclayout->eccpos, sizeof(oi.eccpos));
871 		memcpy(&oi.oobfree, mtd->ecclayout->oobfree,
872 		       sizeof(oi.oobfree));
873 		oi.eccbytes = mtd->ecclayout->eccbytes;
874 
875 		if (copy_to_user(argp, &oi, sizeof(struct nand_oobinfo)))
876 			return -EFAULT;
877 		break;
878 	}
879 
880 	case MEMGETBADBLOCK:
881 	{
882 		loff_t offs;
883 
884 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
885 			return -EFAULT;
886 		if (!mtd->block_isbad)
887 			ret = -EOPNOTSUPP;
888 		else
889 			return mtd_block_isbad(mtd, offs);
890 		break;
891 	}
892 
893 	case MEMSETBADBLOCK:
894 	{
895 		loff_t offs;
896 
897 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
898 			return -EFAULT;
899 		if (!mtd->block_markbad)
900 			ret = -EOPNOTSUPP;
901 		else
902 			return mtd_block_markbad(mtd, offs);
903 		break;
904 	}
905 
906 #ifdef CONFIG_HAVE_MTD_OTP
907 	case OTPSELECT:
908 	{
909 		int mode;
910 		if (copy_from_user(&mode, argp, sizeof(int)))
911 			return -EFAULT;
912 
913 		mfi->mode = MTD_FILE_MODE_NORMAL;
914 
915 		ret = otp_select_filemode(mfi, mode);
916 
917 		file->f_pos = 0;
918 		break;
919 	}
920 
921 	case OTPGETREGIONCOUNT:
922 	case OTPGETREGIONINFO:
923 	{
924 		struct otp_info *buf = kmalloc(4096, GFP_KERNEL);
925 		if (!buf)
926 			return -ENOMEM;
927 		ret = -EOPNOTSUPP;
928 		switch (mfi->mode) {
929 		case MTD_FILE_MODE_OTP_FACTORY:
930 			if (mtd->get_fact_prot_info)
931 				ret = mtd_get_fact_prot_info(mtd, buf, 4096);
932 			break;
933 		case MTD_FILE_MODE_OTP_USER:
934 			if (mtd->get_user_prot_info)
935 				ret = mtd_get_user_prot_info(mtd, buf, 4096);
936 			break;
937 		default:
938 			break;
939 		}
940 		if (ret >= 0) {
941 			if (cmd == OTPGETREGIONCOUNT) {
942 				int nbr = ret / sizeof(struct otp_info);
943 				ret = copy_to_user(argp, &nbr, sizeof(int));
944 			} else
945 				ret = copy_to_user(argp, buf, ret);
946 			if (ret)
947 				ret = -EFAULT;
948 		}
949 		kfree(buf);
950 		break;
951 	}
952 
953 	case OTPLOCK:
954 	{
955 		struct otp_info oinfo;
956 
957 		if (mfi->mode != MTD_FILE_MODE_OTP_USER)
958 			return -EINVAL;
959 		if (copy_from_user(&oinfo, argp, sizeof(oinfo)))
960 			return -EFAULT;
961 		if (!mtd->lock_user_prot_reg)
962 			return -EOPNOTSUPP;
963 		ret = mtd_lock_user_prot_reg(mtd, oinfo.start, oinfo.length);
964 		break;
965 	}
966 #endif
967 
968 	/* This ioctl is being deprecated - it truncates the ECC layout */
969 	case ECCGETLAYOUT:
970 	{
971 		struct nand_ecclayout_user *usrlay;
972 
973 		if (!mtd->ecclayout)
974 			return -EOPNOTSUPP;
975 
976 		usrlay = kmalloc(sizeof(*usrlay), GFP_KERNEL);
977 		if (!usrlay)
978 			return -ENOMEM;
979 
980 		shrink_ecclayout(mtd->ecclayout, usrlay);
981 
982 		if (copy_to_user(argp, usrlay, sizeof(*usrlay)))
983 			ret = -EFAULT;
984 		kfree(usrlay);
985 		break;
986 	}
987 
988 	case ECCGETSTATS:
989 	{
990 		if (copy_to_user(argp, &mtd->ecc_stats,
991 				 sizeof(struct mtd_ecc_stats)))
992 			return -EFAULT;
993 		break;
994 	}
995 
996 	case MTDFILEMODE:
997 	{
998 		mfi->mode = 0;
999 
1000 		switch(arg) {
1001 		case MTD_FILE_MODE_OTP_FACTORY:
1002 		case MTD_FILE_MODE_OTP_USER:
1003 			ret = otp_select_filemode(mfi, arg);
1004 			break;
1005 
1006 		case MTD_FILE_MODE_RAW:
1007 			if (!mtd_has_oob(mtd))
1008 				return -EOPNOTSUPP;
1009 			mfi->mode = arg;
1010 
1011 		case MTD_FILE_MODE_NORMAL:
1012 			break;
1013 		default:
1014 			ret = -EINVAL;
1015 		}
1016 		file->f_pos = 0;
1017 		break;
1018 	}
1019 
1020 	case BLKPG:
1021 	{
1022 		ret = mtdchar_blkpg_ioctl(mtd,
1023 		      (struct blkpg_ioctl_arg __user *)arg);
1024 		break;
1025 	}
1026 
1027 	case BLKRRPART:
1028 	{
1029 		/* No reread partition feature. Just return ok */
1030 		ret = 0;
1031 		break;
1032 	}
1033 
1034 	default:
1035 		ret = -ENOTTY;
1036 	}
1037 
1038 	return ret;
1039 } /* memory_ioctl */
1040 
1041 static long mtdchar_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
1042 {
1043 	int ret;
1044 
1045 	mutex_lock(&mtd_mutex);
1046 	ret = mtdchar_ioctl(file, cmd, arg);
1047 	mutex_unlock(&mtd_mutex);
1048 
1049 	return ret;
1050 }
1051 
1052 #ifdef CONFIG_COMPAT
1053 
1054 struct mtd_oob_buf32 {
1055 	u_int32_t start;
1056 	u_int32_t length;
1057 	compat_caddr_t ptr;	/* unsigned char* */
1058 };
1059 
1060 #define MEMWRITEOOB32		_IOWR('M', 3, struct mtd_oob_buf32)
1061 #define MEMREADOOB32		_IOWR('M', 4, struct mtd_oob_buf32)
1062 
1063 static long mtdchar_compat_ioctl(struct file *file, unsigned int cmd,
1064 	unsigned long arg)
1065 {
1066 	struct mtd_file_info *mfi = file->private_data;
1067 	struct mtd_info *mtd = mfi->mtd;
1068 	void __user *argp = compat_ptr(arg);
1069 	int ret = 0;
1070 
1071 	mutex_lock(&mtd_mutex);
1072 
1073 	switch (cmd) {
1074 	case MEMWRITEOOB32:
1075 	{
1076 		struct mtd_oob_buf32 buf;
1077 		struct mtd_oob_buf32 __user *buf_user = argp;
1078 
1079 		if (copy_from_user(&buf, argp, sizeof(buf)))
1080 			ret = -EFAULT;
1081 		else
1082 			ret = mtdchar_writeoob(file, mtd, buf.start,
1083 				buf.length, compat_ptr(buf.ptr),
1084 				&buf_user->length);
1085 		break;
1086 	}
1087 
1088 	case MEMREADOOB32:
1089 	{
1090 		struct mtd_oob_buf32 buf;
1091 		struct mtd_oob_buf32 __user *buf_user = argp;
1092 
1093 		/* NOTE: writes return length to buf->start */
1094 		if (copy_from_user(&buf, argp, sizeof(buf)))
1095 			ret = -EFAULT;
1096 		else
1097 			ret = mtdchar_readoob(file, mtd, buf.start,
1098 				buf.length, compat_ptr(buf.ptr),
1099 				&buf_user->start);
1100 		break;
1101 	}
1102 	default:
1103 		ret = mtdchar_ioctl(file, cmd, (unsigned long)argp);
1104 	}
1105 
1106 	mutex_unlock(&mtd_mutex);
1107 
1108 	return ret;
1109 }
1110 
1111 #endif /* CONFIG_COMPAT */
1112 
1113 /*
1114  * try to determine where a shared mapping can be made
1115  * - only supported for NOMMU at the moment (MMU can't doesn't copy private
1116  *   mappings)
1117  */
1118 #ifndef CONFIG_MMU
1119 static unsigned long mtdchar_get_unmapped_area(struct file *file,
1120 					   unsigned long addr,
1121 					   unsigned long len,
1122 					   unsigned long pgoff,
1123 					   unsigned long flags)
1124 {
1125 	struct mtd_file_info *mfi = file->private_data;
1126 	struct mtd_info *mtd = mfi->mtd;
1127 	unsigned long offset;
1128 	int ret;
1129 
1130 	if (addr != 0)
1131 		return (unsigned long) -EINVAL;
1132 
1133 	if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT))
1134 		return (unsigned long) -EINVAL;
1135 
1136 	offset = pgoff << PAGE_SHIFT;
1137 	if (offset > mtd->size - len)
1138 		return (unsigned long) -EINVAL;
1139 
1140 	ret = mtd_get_unmapped_area(mtd, len, offset, flags);
1141 	return ret == -EOPNOTSUPP ? -ENOSYS : ret;
1142 }
1143 #endif
1144 
1145 /*
1146  * set up a mapping for shared memory segments
1147  */
1148 static int mtdchar_mmap(struct file *file, struct vm_area_struct *vma)
1149 {
1150 #ifdef CONFIG_MMU
1151 	struct mtd_file_info *mfi = file->private_data;
1152 	struct mtd_info *mtd = mfi->mtd;
1153 	struct map_info *map = mtd->priv;
1154 	unsigned long start;
1155 	unsigned long off;
1156 	u32 len;
1157 
1158 	if (mtd->type == MTD_RAM || mtd->type == MTD_ROM) {
1159 		off = vma->vm_pgoff << PAGE_SHIFT;
1160 		start = map->phys;
1161 		len = PAGE_ALIGN((start & ~PAGE_MASK) + map->size);
1162 		start &= PAGE_MASK;
1163 		if ((vma->vm_end - vma->vm_start + off) > len)
1164 			return -EINVAL;
1165 
1166 		off += start;
1167 		vma->vm_pgoff = off >> PAGE_SHIFT;
1168 		vma->vm_flags |= VM_IO | VM_RESERVED;
1169 
1170 #ifdef pgprot_noncached
1171 		if (file->f_flags & O_DSYNC || off >= __pa(high_memory))
1172 			vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1173 #endif
1174 		if (io_remap_pfn_range(vma, vma->vm_start, off >> PAGE_SHIFT,
1175 				       vma->vm_end - vma->vm_start,
1176 				       vma->vm_page_prot))
1177 			return -EAGAIN;
1178 
1179 		return 0;
1180 	}
1181 	return -ENOSYS;
1182 #else
1183 	return vma->vm_flags & VM_SHARED ? 0 : -ENOSYS;
1184 #endif
1185 }
1186 
1187 static const struct file_operations mtd_fops = {
1188 	.owner		= THIS_MODULE,
1189 	.llseek		= mtdchar_lseek,
1190 	.read		= mtdchar_read,
1191 	.write		= mtdchar_write,
1192 	.unlocked_ioctl	= mtdchar_unlocked_ioctl,
1193 #ifdef CONFIG_COMPAT
1194 	.compat_ioctl	= mtdchar_compat_ioctl,
1195 #endif
1196 	.open		= mtdchar_open,
1197 	.release	= mtdchar_close,
1198 	.mmap		= mtdchar_mmap,
1199 #ifndef CONFIG_MMU
1200 	.get_unmapped_area = mtdchar_get_unmapped_area,
1201 #endif
1202 };
1203 
1204 static struct dentry *mtd_inodefs_mount(struct file_system_type *fs_type,
1205 				int flags, const char *dev_name, void *data)
1206 {
1207 	return mount_pseudo(fs_type, "mtd_inode:", NULL, NULL, MTD_INODE_FS_MAGIC);
1208 }
1209 
1210 static struct file_system_type mtd_inodefs_type = {
1211        .name = "mtd_inodefs",
1212        .mount = mtd_inodefs_mount,
1213        .kill_sb = kill_anon_super,
1214 };
1215 
1216 static void mtdchar_notify_add(struct mtd_info *mtd)
1217 {
1218 }
1219 
1220 static void mtdchar_notify_remove(struct mtd_info *mtd)
1221 {
1222 	struct inode *mtd_ino = ilookup(mtd_inode_mnt->mnt_sb, mtd->index);
1223 
1224 	if (mtd_ino) {
1225 		/* Destroy the inode if it exists */
1226 		clear_nlink(mtd_ino);
1227 		iput(mtd_ino);
1228 	}
1229 }
1230 
1231 static struct mtd_notifier mtdchar_notifier = {
1232 	.add = mtdchar_notify_add,
1233 	.remove = mtdchar_notify_remove,
1234 };
1235 
1236 static int __init init_mtdchar(void)
1237 {
1238 	int ret;
1239 
1240 	ret = __register_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS,
1241 				   "mtd", &mtd_fops);
1242 	if (ret < 0) {
1243 		pr_notice("Can't allocate major number %d for "
1244 				"Memory Technology Devices.\n", MTD_CHAR_MAJOR);
1245 		return ret;
1246 	}
1247 
1248 	ret = register_filesystem(&mtd_inodefs_type);
1249 	if (ret) {
1250 		pr_notice("Can't register mtd_inodefs filesystem: %d\n", ret);
1251 		goto err_unregister_chdev;
1252 	}
1253 
1254 	mtd_inode_mnt = kern_mount(&mtd_inodefs_type);
1255 	if (IS_ERR(mtd_inode_mnt)) {
1256 		ret = PTR_ERR(mtd_inode_mnt);
1257 		pr_notice("Error mounting mtd_inodefs filesystem: %d\n", ret);
1258 		goto err_unregister_filesystem;
1259 	}
1260 	register_mtd_user(&mtdchar_notifier);
1261 
1262 	return ret;
1263 
1264 err_unregister_filesystem:
1265 	unregister_filesystem(&mtd_inodefs_type);
1266 err_unregister_chdev:
1267 	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1268 	return ret;
1269 }
1270 
1271 static void __exit cleanup_mtdchar(void)
1272 {
1273 	unregister_mtd_user(&mtdchar_notifier);
1274 	kern_unmount(mtd_inode_mnt);
1275 	unregister_filesystem(&mtd_inodefs_type);
1276 	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1277 }
1278 
1279 module_init(init_mtdchar);
1280 module_exit(cleanup_mtdchar);
1281 
1282 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);
1283 
1284 MODULE_LICENSE("GPL");
1285 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
1286 MODULE_DESCRIPTION("Direct character-device access to MTD devices");
1287 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);
1288