xref: /linux/drivers/mtd/mtdchar.c (revision d264f72ae56245358025109d9d066d159589802d)
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=0;
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, &retlen, kbuf);
221 			break;
222 		case MTD_FILE_MODE_RAW:
223 		{
224 			struct mtd_oob_ops ops;
225 
226 			ops.mode = MTD_OPS_RAW;
227 			ops.datbuf = kbuf;
228 			ops.oobbuf = NULL;
229 			ops.len = len;
230 
231 			ret = mtd_read_oob(mtd, *ppos, &ops);
232 			retlen = ops.retlen;
233 			break;
234 		}
235 		default:
236 			ret = mtd_read(mtd, *ppos, len, &retlen, kbuf);
237 		}
238 		/* Nand returns -EBADMSG on ECC errors, but it returns
239 		 * the data. For our userspace tools it is important
240 		 * to dump areas with ECC errors!
241 		 * For kernel internal usage it also might return -EUCLEAN
242 		 * to signal the caller that a bitflip has occurred and has
243 		 * been corrected by the ECC algorithm.
244 		 * Userspace software which accesses NAND this way
245 		 * must be aware of the fact that it deals with NAND
246 		 */
247 		if (!ret || mtd_is_bitflip_or_eccerr(ret)) {
248 			*ppos += retlen;
249 			if (copy_to_user(buf, kbuf, retlen)) {
250 				kfree(kbuf);
251 				return -EFAULT;
252 			}
253 			else
254 				total_retlen += retlen;
255 
256 			count -= retlen;
257 			buf += retlen;
258 			if (retlen == 0)
259 				count = 0;
260 		}
261 		else {
262 			kfree(kbuf);
263 			return ret;
264 		}
265 
266 	}
267 
268 	kfree(kbuf);
269 	return total_retlen;
270 } /* mtdchar_read */
271 
272 static ssize_t mtdchar_write(struct file *file, const char __user *buf, size_t count,
273 			loff_t *ppos)
274 {
275 	struct mtd_file_info *mfi = file->private_data;
276 	struct mtd_info *mtd = mfi->mtd;
277 	size_t size = count;
278 	char *kbuf;
279 	size_t retlen;
280 	size_t total_retlen=0;
281 	int ret=0;
282 	int len;
283 
284 	pr_debug("MTD_write\n");
285 
286 	if (*ppos == mtd->size)
287 		return -ENOSPC;
288 
289 	if (*ppos + count > mtd->size)
290 		count = mtd->size - *ppos;
291 
292 	if (!count)
293 		return 0;
294 
295 	kbuf = mtd_kmalloc_up_to(mtd, &size);
296 	if (!kbuf)
297 		return -ENOMEM;
298 
299 	while (count) {
300 		len = min_t(size_t, count, size);
301 
302 		if (copy_from_user(kbuf, buf, len)) {
303 			kfree(kbuf);
304 			return -EFAULT;
305 		}
306 
307 		switch (mfi->mode) {
308 		case MTD_FILE_MODE_OTP_FACTORY:
309 			ret = -EROFS;
310 			break;
311 		case MTD_FILE_MODE_OTP_USER:
312 			if (!mtd->write_user_prot_reg) {
313 				ret = -EOPNOTSUPP;
314 				break;
315 			}
316 			ret = mtd->write_user_prot_reg(mtd, *ppos, len, &retlen, kbuf);
317 			break;
318 
319 		case MTD_FILE_MODE_RAW:
320 		{
321 			struct mtd_oob_ops ops;
322 
323 			ops.mode = MTD_OPS_RAW;
324 			ops.datbuf = kbuf;
325 			ops.oobbuf = NULL;
326 			ops.ooboffs = 0;
327 			ops.len = len;
328 
329 			ret = mtd_write_oob(mtd, *ppos, &ops);
330 			retlen = ops.retlen;
331 			break;
332 		}
333 
334 		default:
335 			ret = mtd_write(mtd, *ppos, len, &retlen, kbuf);
336 		}
337 		if (!ret) {
338 			*ppos += retlen;
339 			total_retlen += retlen;
340 			count -= retlen;
341 			buf += retlen;
342 		}
343 		else {
344 			kfree(kbuf);
345 			return ret;
346 		}
347 	}
348 
349 	kfree(kbuf);
350 	return total_retlen;
351 } /* mtdchar_write */
352 
353 /*======================================================================
354 
355     IOCTL calls for getting device parameters.
356 
357 ======================================================================*/
358 static void mtdchar_erase_callback (struct erase_info *instr)
359 {
360 	wake_up((wait_queue_head_t *)instr->priv);
361 }
362 
363 #ifdef CONFIG_HAVE_MTD_OTP
364 static int otp_select_filemode(struct mtd_file_info *mfi, int mode)
365 {
366 	struct mtd_info *mtd = mfi->mtd;
367 	int ret = 0;
368 
369 	switch (mode) {
370 	case MTD_OTP_FACTORY:
371 		if (!mtd->read_fact_prot_reg)
372 			ret = -EOPNOTSUPP;
373 		else
374 			mfi->mode = MTD_FILE_MODE_OTP_FACTORY;
375 		break;
376 	case MTD_OTP_USER:
377 		if (!mtd->read_fact_prot_reg)
378 			ret = -EOPNOTSUPP;
379 		else
380 			mfi->mode = MTD_FILE_MODE_OTP_USER;
381 		break;
382 	default:
383 		ret = -EINVAL;
384 	case MTD_OTP_OFF:
385 		break;
386 	}
387 	return ret;
388 }
389 #else
390 # define otp_select_filemode(f,m)	-EOPNOTSUPP
391 #endif
392 
393 static int mtdchar_writeoob(struct file *file, struct mtd_info *mtd,
394 	uint64_t start, uint32_t length, void __user *ptr,
395 	uint32_t __user *retp)
396 {
397 	struct mtd_file_info *mfi = file->private_data;
398 	struct mtd_oob_ops ops;
399 	uint32_t retlen;
400 	int ret = 0;
401 
402 	if (!(file->f_mode & FMODE_WRITE))
403 		return -EPERM;
404 
405 	if (length > 4096)
406 		return -EINVAL;
407 
408 	if (!mtd->write_oob)
409 		ret = -EOPNOTSUPP;
410 	else
411 		ret = access_ok(VERIFY_READ, ptr, length) ? 0 : -EFAULT;
412 
413 	if (ret)
414 		return ret;
415 
416 	ops.ooblen = length;
417 	ops.ooboffs = start & (mtd->writesize - 1);
418 	ops.datbuf = NULL;
419 	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
420 		MTD_OPS_PLACE_OOB;
421 
422 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
423 		return -EINVAL;
424 
425 	ops.oobbuf = memdup_user(ptr, length);
426 	if (IS_ERR(ops.oobbuf))
427 		return PTR_ERR(ops.oobbuf);
428 
429 	start &= ~((uint64_t)mtd->writesize - 1);
430 	ret = mtd_write_oob(mtd, start, &ops);
431 
432 	if (ops.oobretlen > 0xFFFFFFFFU)
433 		ret = -EOVERFLOW;
434 	retlen = ops.oobretlen;
435 	if (copy_to_user(retp, &retlen, sizeof(length)))
436 		ret = -EFAULT;
437 
438 	kfree(ops.oobbuf);
439 	return ret;
440 }
441 
442 static int mtdchar_readoob(struct file *file, struct mtd_info *mtd,
443 	uint64_t start, uint32_t length, void __user *ptr,
444 	uint32_t __user *retp)
445 {
446 	struct mtd_file_info *mfi = file->private_data;
447 	struct mtd_oob_ops ops;
448 	int ret = 0;
449 
450 	if (length > 4096)
451 		return -EINVAL;
452 
453 	if (!mtd->read_oob)
454 		ret = -EOPNOTSUPP;
455 	else
456 		ret = access_ok(VERIFY_WRITE, ptr,
457 				length) ? 0 : -EFAULT;
458 	if (ret)
459 		return ret;
460 
461 	ops.ooblen = length;
462 	ops.ooboffs = start & (mtd->writesize - 1);
463 	ops.datbuf = NULL;
464 	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
465 		MTD_OPS_PLACE_OOB;
466 
467 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
468 		return -EINVAL;
469 
470 	ops.oobbuf = kmalloc(length, GFP_KERNEL);
471 	if (!ops.oobbuf)
472 		return -ENOMEM;
473 
474 	start &= ~((uint64_t)mtd->writesize - 1);
475 	ret = mtd_read_oob(mtd, start, &ops);
476 
477 	if (put_user(ops.oobretlen, retp))
478 		ret = -EFAULT;
479 	else if (ops.oobretlen && copy_to_user(ptr, ops.oobbuf,
480 					    ops.oobretlen))
481 		ret = -EFAULT;
482 
483 	kfree(ops.oobbuf);
484 
485 	/*
486 	 * NAND returns -EBADMSG on ECC errors, but it returns the OOB
487 	 * data. For our userspace tools it is important to dump areas
488 	 * with ECC errors!
489 	 * For kernel internal usage it also might return -EUCLEAN
490 	 * to signal the caller that a bitflip has occured and has
491 	 * been corrected by the ECC algorithm.
492 	 *
493 	 * Note: currently the standard NAND function, nand_read_oob_std,
494 	 * does not calculate ECC for the OOB area, so do not rely on
495 	 * this behavior unless you have replaced it with your own.
496 	 */
497 	if (mtd_is_bitflip_or_eccerr(ret))
498 		return 0;
499 
500 	return ret;
501 }
502 
503 /*
504  * Copies (and truncates, if necessary) data from the larger struct,
505  * nand_ecclayout, to the smaller, deprecated layout struct,
506  * nand_ecclayout_user. This is necessary only to support the deprecated
507  * API ioctl ECCGETLAYOUT while allowing all new functionality to use
508  * nand_ecclayout flexibly (i.e. the struct may change size in new
509  * releases without requiring major rewrites).
510  */
511 static int shrink_ecclayout(const struct nand_ecclayout *from,
512 		struct nand_ecclayout_user *to)
513 {
514 	int i;
515 
516 	if (!from || !to)
517 		return -EINVAL;
518 
519 	memset(to, 0, sizeof(*to));
520 
521 	to->eccbytes = min((int)from->eccbytes, MTD_MAX_ECCPOS_ENTRIES);
522 	for (i = 0; i < to->eccbytes; i++)
523 		to->eccpos[i] = from->eccpos[i];
524 
525 	for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES; i++) {
526 		if (from->oobfree[i].length == 0 &&
527 				from->oobfree[i].offset == 0)
528 			break;
529 		to->oobavail += from->oobfree[i].length;
530 		to->oobfree[i] = from->oobfree[i];
531 	}
532 
533 	return 0;
534 }
535 
536 static int mtdchar_blkpg_ioctl(struct mtd_info *mtd,
537 			   struct blkpg_ioctl_arg __user *arg)
538 {
539 	struct blkpg_ioctl_arg a;
540 	struct blkpg_partition p;
541 
542 	if (!capable(CAP_SYS_ADMIN))
543 		return -EPERM;
544 
545 	if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
546 		return -EFAULT;
547 
548 	if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
549 		return -EFAULT;
550 
551 	switch (a.op) {
552 	case BLKPG_ADD_PARTITION:
553 
554 		/* Only master mtd device must be used to add partitions */
555 		if (mtd_is_partition(mtd))
556 			return -EINVAL;
557 
558 		return mtd_add_partition(mtd, p.devname, p.start, p.length);
559 
560 	case BLKPG_DEL_PARTITION:
561 
562 		if (p.pno < 0)
563 			return -EINVAL;
564 
565 		return mtd_del_partition(mtd, p.pno);
566 
567 	default:
568 		return -EINVAL;
569 	}
570 }
571 
572 static int mtdchar_write_ioctl(struct mtd_info *mtd,
573 		struct mtd_write_req __user *argp)
574 {
575 	struct mtd_write_req req;
576 	struct mtd_oob_ops ops;
577 	void __user *usr_data, *usr_oob;
578 	int ret;
579 
580 	if (copy_from_user(&req, argp, sizeof(req)) ||
581 			!access_ok(VERIFY_READ, req.usr_data, req.len) ||
582 			!access_ok(VERIFY_READ, req.usr_oob, req.ooblen))
583 		return -EFAULT;
584 	if (!mtd->write_oob)
585 		return -EOPNOTSUPP;
586 
587 	ops.mode = req.mode;
588 	ops.len = (size_t)req.len;
589 	ops.ooblen = (size_t)req.ooblen;
590 	ops.ooboffs = 0;
591 
592 	usr_data = (void __user *)(uintptr_t)req.usr_data;
593 	usr_oob = (void __user *)(uintptr_t)req.usr_oob;
594 
595 	if (req.usr_data) {
596 		ops.datbuf = memdup_user(usr_data, ops.len);
597 		if (IS_ERR(ops.datbuf))
598 			return PTR_ERR(ops.datbuf);
599 	} else {
600 		ops.datbuf = NULL;
601 	}
602 
603 	if (req.usr_oob) {
604 		ops.oobbuf = memdup_user(usr_oob, ops.ooblen);
605 		if (IS_ERR(ops.oobbuf)) {
606 			kfree(ops.datbuf);
607 			return PTR_ERR(ops.oobbuf);
608 		}
609 	} else {
610 		ops.oobbuf = NULL;
611 	}
612 
613 	ret = mtd_write_oob(mtd, (loff_t)req.start, &ops);
614 
615 	kfree(ops.datbuf);
616 	kfree(ops.oobbuf);
617 
618 	return ret;
619 }
620 
621 static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg)
622 {
623 	struct mtd_file_info *mfi = file->private_data;
624 	struct mtd_info *mtd = mfi->mtd;
625 	void __user *argp = (void __user *)arg;
626 	int ret = 0;
627 	u_long size;
628 	struct mtd_info_user info;
629 
630 	pr_debug("MTD_ioctl\n");
631 
632 	size = (cmd & IOCSIZE_MASK) >> IOCSIZE_SHIFT;
633 	if (cmd & IOC_IN) {
634 		if (!access_ok(VERIFY_READ, argp, size))
635 			return -EFAULT;
636 	}
637 	if (cmd & IOC_OUT) {
638 		if (!access_ok(VERIFY_WRITE, argp, size))
639 			return -EFAULT;
640 	}
641 
642 	switch (cmd) {
643 	case MEMGETREGIONCOUNT:
644 		if (copy_to_user(argp, &(mtd->numeraseregions), sizeof(int)))
645 			return -EFAULT;
646 		break;
647 
648 	case MEMGETREGIONINFO:
649 	{
650 		uint32_t ur_idx;
651 		struct mtd_erase_region_info *kr;
652 		struct region_info_user __user *ur = argp;
653 
654 		if (get_user(ur_idx, &(ur->regionindex)))
655 			return -EFAULT;
656 
657 		if (ur_idx >= mtd->numeraseregions)
658 			return -EINVAL;
659 
660 		kr = &(mtd->eraseregions[ur_idx]);
661 
662 		if (put_user(kr->offset, &(ur->offset))
663 		    || put_user(kr->erasesize, &(ur->erasesize))
664 		    || put_user(kr->numblocks, &(ur->numblocks)))
665 			return -EFAULT;
666 
667 		break;
668 	}
669 
670 	case MEMGETINFO:
671 		memset(&info, 0, sizeof(info));
672 		info.type	= mtd->type;
673 		info.flags	= mtd->flags;
674 		info.size	= mtd->size;
675 		info.erasesize	= mtd->erasesize;
676 		info.writesize	= mtd->writesize;
677 		info.oobsize	= mtd->oobsize;
678 		/* The below field is obsolete */
679 		info.padding	= 0;
680 		if (copy_to_user(argp, &info, sizeof(struct mtd_info_user)))
681 			return -EFAULT;
682 		break;
683 
684 	case MEMERASE:
685 	case MEMERASE64:
686 	{
687 		struct erase_info *erase;
688 
689 		if(!(file->f_mode & FMODE_WRITE))
690 			return -EPERM;
691 
692 		erase=kzalloc(sizeof(struct erase_info),GFP_KERNEL);
693 		if (!erase)
694 			ret = -ENOMEM;
695 		else {
696 			wait_queue_head_t waitq;
697 			DECLARE_WAITQUEUE(wait, current);
698 
699 			init_waitqueue_head(&waitq);
700 
701 			if (cmd == MEMERASE64) {
702 				struct erase_info_user64 einfo64;
703 
704 				if (copy_from_user(&einfo64, argp,
705 					    sizeof(struct erase_info_user64))) {
706 					kfree(erase);
707 					return -EFAULT;
708 				}
709 				erase->addr = einfo64.start;
710 				erase->len = einfo64.length;
711 			} else {
712 				struct erase_info_user einfo32;
713 
714 				if (copy_from_user(&einfo32, argp,
715 					    sizeof(struct erase_info_user))) {
716 					kfree(erase);
717 					return -EFAULT;
718 				}
719 				erase->addr = einfo32.start;
720 				erase->len = einfo32.length;
721 			}
722 			erase->mtd = mtd;
723 			erase->callback = mtdchar_erase_callback;
724 			erase->priv = (unsigned long)&waitq;
725 
726 			/*
727 			  FIXME: Allow INTERRUPTIBLE. Which means
728 			  not having the wait_queue head on the stack.
729 
730 			  If the wq_head is on the stack, and we
731 			  leave because we got interrupted, then the
732 			  wq_head is no longer there when the
733 			  callback routine tries to wake us up.
734 			*/
735 			ret = mtd_erase(mtd, erase);
736 			if (!ret) {
737 				set_current_state(TASK_UNINTERRUPTIBLE);
738 				add_wait_queue(&waitq, &wait);
739 				if (erase->state != MTD_ERASE_DONE &&
740 				    erase->state != MTD_ERASE_FAILED)
741 					schedule();
742 				remove_wait_queue(&waitq, &wait);
743 				set_current_state(TASK_RUNNING);
744 
745 				ret = (erase->state == MTD_ERASE_FAILED)?-EIO:0;
746 			}
747 			kfree(erase);
748 		}
749 		break;
750 	}
751 
752 	case MEMWRITEOOB:
753 	{
754 		struct mtd_oob_buf buf;
755 		struct mtd_oob_buf __user *buf_user = argp;
756 
757 		/* NOTE: writes return length to buf_user->length */
758 		if (copy_from_user(&buf, argp, sizeof(buf)))
759 			ret = -EFAULT;
760 		else
761 			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
762 				buf.ptr, &buf_user->length);
763 		break;
764 	}
765 
766 	case MEMREADOOB:
767 	{
768 		struct mtd_oob_buf buf;
769 		struct mtd_oob_buf __user *buf_user = argp;
770 
771 		/* NOTE: writes return length to buf_user->start */
772 		if (copy_from_user(&buf, argp, sizeof(buf)))
773 			ret = -EFAULT;
774 		else
775 			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
776 				buf.ptr, &buf_user->start);
777 		break;
778 	}
779 
780 	case MEMWRITEOOB64:
781 	{
782 		struct mtd_oob_buf64 buf;
783 		struct mtd_oob_buf64 __user *buf_user = argp;
784 
785 		if (copy_from_user(&buf, argp, sizeof(buf)))
786 			ret = -EFAULT;
787 		else
788 			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
789 				(void __user *)(uintptr_t)buf.usr_ptr,
790 				&buf_user->length);
791 		break;
792 	}
793 
794 	case MEMREADOOB64:
795 	{
796 		struct mtd_oob_buf64 buf;
797 		struct mtd_oob_buf64 __user *buf_user = argp;
798 
799 		if (copy_from_user(&buf, argp, sizeof(buf)))
800 			ret = -EFAULT;
801 		else
802 			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
803 				(void __user *)(uintptr_t)buf.usr_ptr,
804 				&buf_user->length);
805 		break;
806 	}
807 
808 	case MEMWRITE:
809 	{
810 		ret = mtdchar_write_ioctl(mtd,
811 		      (struct mtd_write_req __user *)arg);
812 		break;
813 	}
814 
815 	case MEMLOCK:
816 	{
817 		struct erase_info_user einfo;
818 
819 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
820 			return -EFAULT;
821 
822 		if (!mtd->lock)
823 			ret = -EOPNOTSUPP;
824 		else
825 			ret = mtd->lock(mtd, einfo.start, einfo.length);
826 		break;
827 	}
828 
829 	case MEMUNLOCK:
830 	{
831 		struct erase_info_user einfo;
832 
833 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
834 			return -EFAULT;
835 
836 		if (!mtd->unlock)
837 			ret = -EOPNOTSUPP;
838 		else
839 			ret = mtd->unlock(mtd, einfo.start, einfo.length);
840 		break;
841 	}
842 
843 	case MEMISLOCKED:
844 	{
845 		struct erase_info_user einfo;
846 
847 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
848 			return -EFAULT;
849 
850 		if (!mtd->is_locked)
851 			ret = -EOPNOTSUPP;
852 		else
853 			ret = mtd->is_locked(mtd, einfo.start, einfo.length);
854 		break;
855 	}
856 
857 	/* Legacy interface */
858 	case MEMGETOOBSEL:
859 	{
860 		struct nand_oobinfo oi;
861 
862 		if (!mtd->ecclayout)
863 			return -EOPNOTSUPP;
864 		if (mtd->ecclayout->eccbytes > ARRAY_SIZE(oi.eccpos))
865 			return -EINVAL;
866 
867 		oi.useecc = MTD_NANDECC_AUTOPLACE;
868 		memcpy(&oi.eccpos, mtd->ecclayout->eccpos, sizeof(oi.eccpos));
869 		memcpy(&oi.oobfree, mtd->ecclayout->oobfree,
870 		       sizeof(oi.oobfree));
871 		oi.eccbytes = mtd->ecclayout->eccbytes;
872 
873 		if (copy_to_user(argp, &oi, sizeof(struct nand_oobinfo)))
874 			return -EFAULT;
875 		break;
876 	}
877 
878 	case MEMGETBADBLOCK:
879 	{
880 		loff_t offs;
881 
882 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
883 			return -EFAULT;
884 		if (!mtd->block_isbad)
885 			ret = -EOPNOTSUPP;
886 		else
887 			return mtd->block_isbad(mtd, offs);
888 		break;
889 	}
890 
891 	case MEMSETBADBLOCK:
892 	{
893 		loff_t offs;
894 
895 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
896 			return -EFAULT;
897 		if (!mtd->block_markbad)
898 			ret = -EOPNOTSUPP;
899 		else
900 			return mtd->block_markbad(mtd, offs);
901 		break;
902 	}
903 
904 #ifdef CONFIG_HAVE_MTD_OTP
905 	case OTPSELECT:
906 	{
907 		int mode;
908 		if (copy_from_user(&mode, argp, sizeof(int)))
909 			return -EFAULT;
910 
911 		mfi->mode = MTD_FILE_MODE_NORMAL;
912 
913 		ret = otp_select_filemode(mfi, mode);
914 
915 		file->f_pos = 0;
916 		break;
917 	}
918 
919 	case OTPGETREGIONCOUNT:
920 	case OTPGETREGIONINFO:
921 	{
922 		struct otp_info *buf = kmalloc(4096, GFP_KERNEL);
923 		if (!buf)
924 			return -ENOMEM;
925 		ret = -EOPNOTSUPP;
926 		switch (mfi->mode) {
927 		case MTD_FILE_MODE_OTP_FACTORY:
928 			if (mtd->get_fact_prot_info)
929 				ret = mtd_get_fact_prot_info(mtd, buf, 4096);
930 			break;
931 		case MTD_FILE_MODE_OTP_USER:
932 			if (mtd->get_user_prot_info)
933 				ret = mtd->get_user_prot_info(mtd, buf, 4096);
934 			break;
935 		default:
936 			break;
937 		}
938 		if (ret >= 0) {
939 			if (cmd == OTPGETREGIONCOUNT) {
940 				int nbr = ret / sizeof(struct otp_info);
941 				ret = copy_to_user(argp, &nbr, sizeof(int));
942 			} else
943 				ret = copy_to_user(argp, buf, ret);
944 			if (ret)
945 				ret = -EFAULT;
946 		}
947 		kfree(buf);
948 		break;
949 	}
950 
951 	case OTPLOCK:
952 	{
953 		struct otp_info oinfo;
954 
955 		if (mfi->mode != MTD_FILE_MODE_OTP_USER)
956 			return -EINVAL;
957 		if (copy_from_user(&oinfo, argp, sizeof(oinfo)))
958 			return -EFAULT;
959 		if (!mtd->lock_user_prot_reg)
960 			return -EOPNOTSUPP;
961 		ret = mtd->lock_user_prot_reg(mtd, oinfo.start, oinfo.length);
962 		break;
963 	}
964 #endif
965 
966 	/* This ioctl is being deprecated - it truncates the ECC layout */
967 	case ECCGETLAYOUT:
968 	{
969 		struct nand_ecclayout_user *usrlay;
970 
971 		if (!mtd->ecclayout)
972 			return -EOPNOTSUPP;
973 
974 		usrlay = kmalloc(sizeof(*usrlay), GFP_KERNEL);
975 		if (!usrlay)
976 			return -ENOMEM;
977 
978 		shrink_ecclayout(mtd->ecclayout, usrlay);
979 
980 		if (copy_to_user(argp, usrlay, sizeof(*usrlay)))
981 			ret = -EFAULT;
982 		kfree(usrlay);
983 		break;
984 	}
985 
986 	case ECCGETSTATS:
987 	{
988 		if (copy_to_user(argp, &mtd->ecc_stats,
989 				 sizeof(struct mtd_ecc_stats)))
990 			return -EFAULT;
991 		break;
992 	}
993 
994 	case MTDFILEMODE:
995 	{
996 		mfi->mode = 0;
997 
998 		switch(arg) {
999 		case MTD_FILE_MODE_OTP_FACTORY:
1000 		case MTD_FILE_MODE_OTP_USER:
1001 			ret = otp_select_filemode(mfi, arg);
1002 			break;
1003 
1004 		case MTD_FILE_MODE_RAW:
1005 			if (!mtd->read_oob || !mtd->write_oob)
1006 				return -EOPNOTSUPP;
1007 			mfi->mode = arg;
1008 
1009 		case MTD_FILE_MODE_NORMAL:
1010 			break;
1011 		default:
1012 			ret = -EINVAL;
1013 		}
1014 		file->f_pos = 0;
1015 		break;
1016 	}
1017 
1018 	case BLKPG:
1019 	{
1020 		ret = mtdchar_blkpg_ioctl(mtd,
1021 		      (struct blkpg_ioctl_arg __user *)arg);
1022 		break;
1023 	}
1024 
1025 	case BLKRRPART:
1026 	{
1027 		/* No reread partition feature. Just return ok */
1028 		ret = 0;
1029 		break;
1030 	}
1031 
1032 	default:
1033 		ret = -ENOTTY;
1034 	}
1035 
1036 	return ret;
1037 } /* memory_ioctl */
1038 
1039 static long mtdchar_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
1040 {
1041 	int ret;
1042 
1043 	mutex_lock(&mtd_mutex);
1044 	ret = mtdchar_ioctl(file, cmd, arg);
1045 	mutex_unlock(&mtd_mutex);
1046 
1047 	return ret;
1048 }
1049 
1050 #ifdef CONFIG_COMPAT
1051 
1052 struct mtd_oob_buf32 {
1053 	u_int32_t start;
1054 	u_int32_t length;
1055 	compat_caddr_t ptr;	/* unsigned char* */
1056 };
1057 
1058 #define MEMWRITEOOB32		_IOWR('M', 3, struct mtd_oob_buf32)
1059 #define MEMREADOOB32		_IOWR('M', 4, struct mtd_oob_buf32)
1060 
1061 static long mtdchar_compat_ioctl(struct file *file, unsigned int cmd,
1062 	unsigned long arg)
1063 {
1064 	struct mtd_file_info *mfi = file->private_data;
1065 	struct mtd_info *mtd = mfi->mtd;
1066 	void __user *argp = compat_ptr(arg);
1067 	int ret = 0;
1068 
1069 	mutex_lock(&mtd_mutex);
1070 
1071 	switch (cmd) {
1072 	case MEMWRITEOOB32:
1073 	{
1074 		struct mtd_oob_buf32 buf;
1075 		struct mtd_oob_buf32 __user *buf_user = argp;
1076 
1077 		if (copy_from_user(&buf, argp, sizeof(buf)))
1078 			ret = -EFAULT;
1079 		else
1080 			ret = mtdchar_writeoob(file, mtd, buf.start,
1081 				buf.length, compat_ptr(buf.ptr),
1082 				&buf_user->length);
1083 		break;
1084 	}
1085 
1086 	case MEMREADOOB32:
1087 	{
1088 		struct mtd_oob_buf32 buf;
1089 		struct mtd_oob_buf32 __user *buf_user = argp;
1090 
1091 		/* NOTE: writes return length to buf->start */
1092 		if (copy_from_user(&buf, argp, sizeof(buf)))
1093 			ret = -EFAULT;
1094 		else
1095 			ret = mtdchar_readoob(file, mtd, buf.start,
1096 				buf.length, compat_ptr(buf.ptr),
1097 				&buf_user->start);
1098 		break;
1099 	}
1100 	default:
1101 		ret = mtdchar_ioctl(file, cmd, (unsigned long)argp);
1102 	}
1103 
1104 	mutex_unlock(&mtd_mutex);
1105 
1106 	return ret;
1107 }
1108 
1109 #endif /* CONFIG_COMPAT */
1110 
1111 /*
1112  * try to determine where a shared mapping can be made
1113  * - only supported for NOMMU at the moment (MMU can't doesn't copy private
1114  *   mappings)
1115  */
1116 #ifndef CONFIG_MMU
1117 static unsigned long mtdchar_get_unmapped_area(struct file *file,
1118 					   unsigned long addr,
1119 					   unsigned long len,
1120 					   unsigned long pgoff,
1121 					   unsigned long flags)
1122 {
1123 	struct mtd_file_info *mfi = file->private_data;
1124 	struct mtd_info *mtd = mfi->mtd;
1125 
1126 	if (mtd->get_unmapped_area) {
1127 		unsigned long offset;
1128 
1129 		if (addr != 0)
1130 			return (unsigned long) -EINVAL;
1131 
1132 		if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT))
1133 			return (unsigned long) -EINVAL;
1134 
1135 		offset = pgoff << PAGE_SHIFT;
1136 		if (offset > mtd->size - len)
1137 			return (unsigned long) -EINVAL;
1138 
1139 		return mtd_get_unmapped_area(mtd, len, offset, flags);
1140 	}
1141 
1142 	/* can't map directly */
1143 	return (unsigned long) -ENOSYS;
1144 }
1145 #endif
1146 
1147 /*
1148  * set up a mapping for shared memory segments
1149  */
1150 static int mtdchar_mmap(struct file *file, struct vm_area_struct *vma)
1151 {
1152 #ifdef CONFIG_MMU
1153 	struct mtd_file_info *mfi = file->private_data;
1154 	struct mtd_info *mtd = mfi->mtd;
1155 	struct map_info *map = mtd->priv;
1156 	unsigned long start;
1157 	unsigned long off;
1158 	u32 len;
1159 
1160 	if (mtd->type == MTD_RAM || mtd->type == MTD_ROM) {
1161 		off = vma->vm_pgoff << PAGE_SHIFT;
1162 		start = map->phys;
1163 		len = PAGE_ALIGN((start & ~PAGE_MASK) + map->size);
1164 		start &= PAGE_MASK;
1165 		if ((vma->vm_end - vma->vm_start + off) > len)
1166 			return -EINVAL;
1167 
1168 		off += start;
1169 		vma->vm_pgoff = off >> PAGE_SHIFT;
1170 		vma->vm_flags |= VM_IO | VM_RESERVED;
1171 
1172 #ifdef pgprot_noncached
1173 		if (file->f_flags & O_DSYNC || off >= __pa(high_memory))
1174 			vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1175 #endif
1176 		if (io_remap_pfn_range(vma, vma->vm_start, off >> PAGE_SHIFT,
1177 				       vma->vm_end - vma->vm_start,
1178 				       vma->vm_page_prot))
1179 			return -EAGAIN;
1180 
1181 		return 0;
1182 	}
1183 	return -ENOSYS;
1184 #else
1185 	return vma->vm_flags & VM_SHARED ? 0 : -ENOSYS;
1186 #endif
1187 }
1188 
1189 static const struct file_operations mtd_fops = {
1190 	.owner		= THIS_MODULE,
1191 	.llseek		= mtdchar_lseek,
1192 	.read		= mtdchar_read,
1193 	.write		= mtdchar_write,
1194 	.unlocked_ioctl	= mtdchar_unlocked_ioctl,
1195 #ifdef CONFIG_COMPAT
1196 	.compat_ioctl	= mtdchar_compat_ioctl,
1197 #endif
1198 	.open		= mtdchar_open,
1199 	.release	= mtdchar_close,
1200 	.mmap		= mtdchar_mmap,
1201 #ifndef CONFIG_MMU
1202 	.get_unmapped_area = mtdchar_get_unmapped_area,
1203 #endif
1204 };
1205 
1206 static struct dentry *mtd_inodefs_mount(struct file_system_type *fs_type,
1207 				int flags, const char *dev_name, void *data)
1208 {
1209 	return mount_pseudo(fs_type, "mtd_inode:", NULL, NULL, MTD_INODE_FS_MAGIC);
1210 }
1211 
1212 static struct file_system_type mtd_inodefs_type = {
1213        .name = "mtd_inodefs",
1214        .mount = mtd_inodefs_mount,
1215        .kill_sb = kill_anon_super,
1216 };
1217 
1218 static void mtdchar_notify_add(struct mtd_info *mtd)
1219 {
1220 }
1221 
1222 static void mtdchar_notify_remove(struct mtd_info *mtd)
1223 {
1224 	struct inode *mtd_ino = ilookup(mtd_inode_mnt->mnt_sb, mtd->index);
1225 
1226 	if (mtd_ino) {
1227 		/* Destroy the inode if it exists */
1228 		clear_nlink(mtd_ino);
1229 		iput(mtd_ino);
1230 	}
1231 }
1232 
1233 static struct mtd_notifier mtdchar_notifier = {
1234 	.add = mtdchar_notify_add,
1235 	.remove = mtdchar_notify_remove,
1236 };
1237 
1238 static int __init init_mtdchar(void)
1239 {
1240 	int ret;
1241 
1242 	ret = __register_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS,
1243 				   "mtd", &mtd_fops);
1244 	if (ret < 0) {
1245 		pr_notice("Can't allocate major number %d for "
1246 				"Memory Technology Devices.\n", MTD_CHAR_MAJOR);
1247 		return ret;
1248 	}
1249 
1250 	ret = register_filesystem(&mtd_inodefs_type);
1251 	if (ret) {
1252 		pr_notice("Can't register mtd_inodefs filesystem: %d\n", ret);
1253 		goto err_unregister_chdev;
1254 	}
1255 
1256 	mtd_inode_mnt = kern_mount(&mtd_inodefs_type);
1257 	if (IS_ERR(mtd_inode_mnt)) {
1258 		ret = PTR_ERR(mtd_inode_mnt);
1259 		pr_notice("Error mounting mtd_inodefs filesystem: %d\n", ret);
1260 		goto err_unregister_filesystem;
1261 	}
1262 	register_mtd_user(&mtdchar_notifier);
1263 
1264 	return ret;
1265 
1266 err_unregister_filesystem:
1267 	unregister_filesystem(&mtd_inodefs_type);
1268 err_unregister_chdev:
1269 	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1270 	return ret;
1271 }
1272 
1273 static void __exit cleanup_mtdchar(void)
1274 {
1275 	unregister_mtd_user(&mtdchar_notifier);
1276 	kern_unmount(mtd_inode_mnt);
1277 	unregister_filesystem(&mtd_inodefs_type);
1278 	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1279 }
1280 
1281 module_init(init_mtdchar);
1282 module_exit(cleanup_mtdchar);
1283 
1284 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);
1285 
1286 MODULE_LICENSE("GPL");
1287 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
1288 MODULE_DESCRIPTION("Direct character-device access to MTD devices");
1289 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);
1290