xref: /linux/drivers/mtd/mtdchar.c (revision a750b5ce5e1174ea68f66bf79962c479f7f23998)
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, &retlen, kbuf);
217 			break;
218 		case MTD_FILE_MODE_OTP_USER:
219 			ret = mtd->read_user_prot_reg(mtd, *ppos, len, &retlen, kbuf);
220 			break;
221 		case MTD_FILE_MODE_RAW:
222 		{
223 			struct mtd_oob_ops ops;
224 
225 			ops.mode = MTD_OPS_RAW;
226 			ops.datbuf = kbuf;
227 			ops.oobbuf = NULL;
228 			ops.len = len;
229 
230 			ret = mtd_read_oob(mtd, *ppos, &ops);
231 			retlen = ops.retlen;
232 			break;
233 		}
234 		default:
235 			ret = mtd_read(mtd, *ppos, len, &retlen, kbuf);
236 		}
237 		/* Nand returns -EBADMSG on ECC errors, but it returns
238 		 * the data. For our userspace tools it is important
239 		 * to dump areas with ECC errors!
240 		 * For kernel internal usage it also might return -EUCLEAN
241 		 * to signal the caller that a bitflip has occurred and has
242 		 * been corrected by the ECC algorithm.
243 		 * Userspace software which accesses NAND this way
244 		 * must be aware of the fact that it deals with NAND
245 		 */
246 		if (!ret || mtd_is_bitflip_or_eccerr(ret)) {
247 			*ppos += retlen;
248 			if (copy_to_user(buf, kbuf, retlen)) {
249 				kfree(kbuf);
250 				return -EFAULT;
251 			}
252 			else
253 				total_retlen += retlen;
254 
255 			count -= retlen;
256 			buf += retlen;
257 			if (retlen == 0)
258 				count = 0;
259 		}
260 		else {
261 			kfree(kbuf);
262 			return ret;
263 		}
264 
265 	}
266 
267 	kfree(kbuf);
268 	return total_retlen;
269 } /* mtdchar_read */
270 
271 static ssize_t mtdchar_write(struct file *file, const char __user *buf, size_t count,
272 			loff_t *ppos)
273 {
274 	struct mtd_file_info *mfi = file->private_data;
275 	struct mtd_info *mtd = mfi->mtd;
276 	size_t size = count;
277 	char *kbuf;
278 	size_t retlen;
279 	size_t total_retlen=0;
280 	int ret=0;
281 	int len;
282 
283 	pr_debug("MTD_write\n");
284 
285 	if (*ppos == mtd->size)
286 		return -ENOSPC;
287 
288 	if (*ppos + count > mtd->size)
289 		count = mtd->size - *ppos;
290 
291 	if (!count)
292 		return 0;
293 
294 	kbuf = mtd_kmalloc_up_to(mtd, &size);
295 	if (!kbuf)
296 		return -ENOMEM;
297 
298 	while (count) {
299 		len = min_t(size_t, count, size);
300 
301 		if (copy_from_user(kbuf, buf, len)) {
302 			kfree(kbuf);
303 			return -EFAULT;
304 		}
305 
306 		switch (mfi->mode) {
307 		case MTD_FILE_MODE_OTP_FACTORY:
308 			ret = -EROFS;
309 			break;
310 		case MTD_FILE_MODE_OTP_USER:
311 			if (!mtd->write_user_prot_reg) {
312 				ret = -EOPNOTSUPP;
313 				break;
314 			}
315 			ret = mtd->write_user_prot_reg(mtd, *ppos, len, &retlen, kbuf);
316 			break;
317 
318 		case MTD_FILE_MODE_RAW:
319 		{
320 			struct mtd_oob_ops ops;
321 
322 			ops.mode = MTD_OPS_RAW;
323 			ops.datbuf = kbuf;
324 			ops.oobbuf = NULL;
325 			ops.ooboffs = 0;
326 			ops.len = len;
327 
328 			ret = mtd_write_oob(mtd, *ppos, &ops);
329 			retlen = ops.retlen;
330 			break;
331 		}
332 
333 		default:
334 			ret = mtd_write(mtd, *ppos, len, &retlen, kbuf);
335 		}
336 		if (!ret) {
337 			*ppos += retlen;
338 			total_retlen += retlen;
339 			count -= retlen;
340 			buf += retlen;
341 		}
342 		else {
343 			kfree(kbuf);
344 			return ret;
345 		}
346 	}
347 
348 	kfree(kbuf);
349 	return total_retlen;
350 } /* mtdchar_write */
351 
352 /*======================================================================
353 
354     IOCTL calls for getting device parameters.
355 
356 ======================================================================*/
357 static void mtdchar_erase_callback (struct erase_info *instr)
358 {
359 	wake_up((wait_queue_head_t *)instr->priv);
360 }
361 
362 #ifdef CONFIG_HAVE_MTD_OTP
363 static int otp_select_filemode(struct mtd_file_info *mfi, int mode)
364 {
365 	struct mtd_info *mtd = mfi->mtd;
366 	int ret = 0;
367 
368 	switch (mode) {
369 	case MTD_OTP_FACTORY:
370 		if (!mtd->read_fact_prot_reg)
371 			ret = -EOPNOTSUPP;
372 		else
373 			mfi->mode = MTD_FILE_MODE_OTP_FACTORY;
374 		break;
375 	case MTD_OTP_USER:
376 		if (!mtd->read_fact_prot_reg)
377 			ret = -EOPNOTSUPP;
378 		else
379 			mfi->mode = MTD_FILE_MODE_OTP_USER;
380 		break;
381 	default:
382 		ret = -EINVAL;
383 	case MTD_OTP_OFF:
384 		break;
385 	}
386 	return ret;
387 }
388 #else
389 # define otp_select_filemode(f,m)	-EOPNOTSUPP
390 #endif
391 
392 static int mtdchar_writeoob(struct file *file, struct mtd_info *mtd,
393 	uint64_t start, uint32_t length, void __user *ptr,
394 	uint32_t __user *retp)
395 {
396 	struct mtd_file_info *mfi = file->private_data;
397 	struct mtd_oob_ops ops;
398 	uint32_t retlen;
399 	int ret = 0;
400 
401 	if (!(file->f_mode & FMODE_WRITE))
402 		return -EPERM;
403 
404 	if (length > 4096)
405 		return -EINVAL;
406 
407 	if (!mtd->write_oob)
408 		ret = -EOPNOTSUPP;
409 	else
410 		ret = access_ok(VERIFY_READ, ptr, length) ? 0 : -EFAULT;
411 
412 	if (ret)
413 		return ret;
414 
415 	ops.ooblen = length;
416 	ops.ooboffs = start & (mtd->writesize - 1);
417 	ops.datbuf = NULL;
418 	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
419 		MTD_OPS_PLACE_OOB;
420 
421 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
422 		return -EINVAL;
423 
424 	ops.oobbuf = memdup_user(ptr, length);
425 	if (IS_ERR(ops.oobbuf))
426 		return PTR_ERR(ops.oobbuf);
427 
428 	start &= ~((uint64_t)mtd->writesize - 1);
429 	ret = mtd_write_oob(mtd, start, &ops);
430 
431 	if (ops.oobretlen > 0xFFFFFFFFU)
432 		ret = -EOVERFLOW;
433 	retlen = ops.oobretlen;
434 	if (copy_to_user(retp, &retlen, sizeof(length)))
435 		ret = -EFAULT;
436 
437 	kfree(ops.oobbuf);
438 	return ret;
439 }
440 
441 static int mtdchar_readoob(struct file *file, struct mtd_info *mtd,
442 	uint64_t start, uint32_t length, void __user *ptr,
443 	uint32_t __user *retp)
444 {
445 	struct mtd_file_info *mfi = file->private_data;
446 	struct mtd_oob_ops ops;
447 	int ret = 0;
448 
449 	if (length > 4096)
450 		return -EINVAL;
451 
452 	if (!mtd->read_oob)
453 		ret = -EOPNOTSUPP;
454 	else
455 		ret = access_ok(VERIFY_WRITE, ptr,
456 				length) ? 0 : -EFAULT;
457 	if (ret)
458 		return ret;
459 
460 	ops.ooblen = length;
461 	ops.ooboffs = start & (mtd->writesize - 1);
462 	ops.datbuf = NULL;
463 	ops.mode = (mfi->mode == MTD_FILE_MODE_RAW) ? MTD_OPS_RAW :
464 		MTD_OPS_PLACE_OOB;
465 
466 	if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
467 		return -EINVAL;
468 
469 	ops.oobbuf = kmalloc(length, GFP_KERNEL);
470 	if (!ops.oobbuf)
471 		return -ENOMEM;
472 
473 	start &= ~((uint64_t)mtd->writesize - 1);
474 	ret = mtd_read_oob(mtd, start, &ops);
475 
476 	if (put_user(ops.oobretlen, retp))
477 		ret = -EFAULT;
478 	else if (ops.oobretlen && copy_to_user(ptr, ops.oobbuf,
479 					    ops.oobretlen))
480 		ret = -EFAULT;
481 
482 	kfree(ops.oobbuf);
483 
484 	/*
485 	 * NAND returns -EBADMSG on ECC errors, but it returns the OOB
486 	 * data. For our userspace tools it is important to dump areas
487 	 * with ECC errors!
488 	 * For kernel internal usage it also might return -EUCLEAN
489 	 * to signal the caller that a bitflip has occured and has
490 	 * been corrected by the ECC algorithm.
491 	 *
492 	 * Note: currently the standard NAND function, nand_read_oob_std,
493 	 * does not calculate ECC for the OOB area, so do not rely on
494 	 * this behavior unless you have replaced it with your own.
495 	 */
496 	if (mtd_is_bitflip_or_eccerr(ret))
497 		return 0;
498 
499 	return ret;
500 }
501 
502 /*
503  * Copies (and truncates, if necessary) data from the larger struct,
504  * nand_ecclayout, to the smaller, deprecated layout struct,
505  * nand_ecclayout_user. This is necessary only to support the deprecated
506  * API ioctl ECCGETLAYOUT while allowing all new functionality to use
507  * nand_ecclayout flexibly (i.e. the struct may change size in new
508  * releases without requiring major rewrites).
509  */
510 static int shrink_ecclayout(const struct nand_ecclayout *from,
511 		struct nand_ecclayout_user *to)
512 {
513 	int i;
514 
515 	if (!from || !to)
516 		return -EINVAL;
517 
518 	memset(to, 0, sizeof(*to));
519 
520 	to->eccbytes = min((int)from->eccbytes, MTD_MAX_ECCPOS_ENTRIES);
521 	for (i = 0; i < to->eccbytes; i++)
522 		to->eccpos[i] = from->eccpos[i];
523 
524 	for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES; i++) {
525 		if (from->oobfree[i].length == 0 &&
526 				from->oobfree[i].offset == 0)
527 			break;
528 		to->oobavail += from->oobfree[i].length;
529 		to->oobfree[i] = from->oobfree[i];
530 	}
531 
532 	return 0;
533 }
534 
535 static int mtdchar_blkpg_ioctl(struct mtd_info *mtd,
536 			   struct blkpg_ioctl_arg __user *arg)
537 {
538 	struct blkpg_ioctl_arg a;
539 	struct blkpg_partition p;
540 
541 	if (!capable(CAP_SYS_ADMIN))
542 		return -EPERM;
543 
544 	if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
545 		return -EFAULT;
546 
547 	if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
548 		return -EFAULT;
549 
550 	switch (a.op) {
551 	case BLKPG_ADD_PARTITION:
552 
553 		/* Only master mtd device must be used to add partitions */
554 		if (mtd_is_partition(mtd))
555 			return -EINVAL;
556 
557 		return mtd_add_partition(mtd, p.devname, p.start, p.length);
558 
559 	case BLKPG_DEL_PARTITION:
560 
561 		if (p.pno < 0)
562 			return -EINVAL;
563 
564 		return mtd_del_partition(mtd, p.pno);
565 
566 	default:
567 		return -EINVAL;
568 	}
569 }
570 
571 static int mtdchar_write_ioctl(struct mtd_info *mtd,
572 		struct mtd_write_req __user *argp)
573 {
574 	struct mtd_write_req req;
575 	struct mtd_oob_ops ops;
576 	void __user *usr_data, *usr_oob;
577 	int ret;
578 
579 	if (copy_from_user(&req, argp, sizeof(req)) ||
580 			!access_ok(VERIFY_READ, req.usr_data, req.len) ||
581 			!access_ok(VERIFY_READ, req.usr_oob, req.ooblen))
582 		return -EFAULT;
583 	if (!mtd->write_oob)
584 		return -EOPNOTSUPP;
585 
586 	ops.mode = req.mode;
587 	ops.len = (size_t)req.len;
588 	ops.ooblen = (size_t)req.ooblen;
589 	ops.ooboffs = 0;
590 
591 	usr_data = (void __user *)(uintptr_t)req.usr_data;
592 	usr_oob = (void __user *)(uintptr_t)req.usr_oob;
593 
594 	if (req.usr_data) {
595 		ops.datbuf = memdup_user(usr_data, ops.len);
596 		if (IS_ERR(ops.datbuf))
597 			return PTR_ERR(ops.datbuf);
598 	} else {
599 		ops.datbuf = NULL;
600 	}
601 
602 	if (req.usr_oob) {
603 		ops.oobbuf = memdup_user(usr_oob, ops.ooblen);
604 		if (IS_ERR(ops.oobbuf)) {
605 			kfree(ops.datbuf);
606 			return PTR_ERR(ops.oobbuf);
607 		}
608 	} else {
609 		ops.oobbuf = NULL;
610 	}
611 
612 	ret = mtd_write_oob(mtd, (loff_t)req.start, &ops);
613 
614 	kfree(ops.datbuf);
615 	kfree(ops.oobbuf);
616 
617 	return ret;
618 }
619 
620 static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg)
621 {
622 	struct mtd_file_info *mfi = file->private_data;
623 	struct mtd_info *mtd = mfi->mtd;
624 	void __user *argp = (void __user *)arg;
625 	int ret = 0;
626 	u_long size;
627 	struct mtd_info_user info;
628 
629 	pr_debug("MTD_ioctl\n");
630 
631 	size = (cmd & IOCSIZE_MASK) >> IOCSIZE_SHIFT;
632 	if (cmd & IOC_IN) {
633 		if (!access_ok(VERIFY_READ, argp, size))
634 			return -EFAULT;
635 	}
636 	if (cmd & IOC_OUT) {
637 		if (!access_ok(VERIFY_WRITE, argp, size))
638 			return -EFAULT;
639 	}
640 
641 	switch (cmd) {
642 	case MEMGETREGIONCOUNT:
643 		if (copy_to_user(argp, &(mtd->numeraseregions), sizeof(int)))
644 			return -EFAULT;
645 		break;
646 
647 	case MEMGETREGIONINFO:
648 	{
649 		uint32_t ur_idx;
650 		struct mtd_erase_region_info *kr;
651 		struct region_info_user __user *ur = argp;
652 
653 		if (get_user(ur_idx, &(ur->regionindex)))
654 			return -EFAULT;
655 
656 		if (ur_idx >= mtd->numeraseregions)
657 			return -EINVAL;
658 
659 		kr = &(mtd->eraseregions[ur_idx]);
660 
661 		if (put_user(kr->offset, &(ur->offset))
662 		    || put_user(kr->erasesize, &(ur->erasesize))
663 		    || put_user(kr->numblocks, &(ur->numblocks)))
664 			return -EFAULT;
665 
666 		break;
667 	}
668 
669 	case MEMGETINFO:
670 		memset(&info, 0, sizeof(info));
671 		info.type	= mtd->type;
672 		info.flags	= mtd->flags;
673 		info.size	= mtd->size;
674 		info.erasesize	= mtd->erasesize;
675 		info.writesize	= mtd->writesize;
676 		info.oobsize	= mtd->oobsize;
677 		/* The below field is obsolete */
678 		info.padding	= 0;
679 		if (copy_to_user(argp, &info, sizeof(struct mtd_info_user)))
680 			return -EFAULT;
681 		break;
682 
683 	case MEMERASE:
684 	case MEMERASE64:
685 	{
686 		struct erase_info *erase;
687 
688 		if(!(file->f_mode & FMODE_WRITE))
689 			return -EPERM;
690 
691 		erase=kzalloc(sizeof(struct erase_info),GFP_KERNEL);
692 		if (!erase)
693 			ret = -ENOMEM;
694 		else {
695 			wait_queue_head_t waitq;
696 			DECLARE_WAITQUEUE(wait, current);
697 
698 			init_waitqueue_head(&waitq);
699 
700 			if (cmd == MEMERASE64) {
701 				struct erase_info_user64 einfo64;
702 
703 				if (copy_from_user(&einfo64, argp,
704 					    sizeof(struct erase_info_user64))) {
705 					kfree(erase);
706 					return -EFAULT;
707 				}
708 				erase->addr = einfo64.start;
709 				erase->len = einfo64.length;
710 			} else {
711 				struct erase_info_user einfo32;
712 
713 				if (copy_from_user(&einfo32, argp,
714 					    sizeof(struct erase_info_user))) {
715 					kfree(erase);
716 					return -EFAULT;
717 				}
718 				erase->addr = einfo32.start;
719 				erase->len = einfo32.length;
720 			}
721 			erase->mtd = mtd;
722 			erase->callback = mtdchar_erase_callback;
723 			erase->priv = (unsigned long)&waitq;
724 
725 			/*
726 			  FIXME: Allow INTERRUPTIBLE. Which means
727 			  not having the wait_queue head on the stack.
728 
729 			  If the wq_head is on the stack, and we
730 			  leave because we got interrupted, then the
731 			  wq_head is no longer there when the
732 			  callback routine tries to wake us up.
733 			*/
734 			ret = mtd_erase(mtd, erase);
735 			if (!ret) {
736 				set_current_state(TASK_UNINTERRUPTIBLE);
737 				add_wait_queue(&waitq, &wait);
738 				if (erase->state != MTD_ERASE_DONE &&
739 				    erase->state != MTD_ERASE_FAILED)
740 					schedule();
741 				remove_wait_queue(&waitq, &wait);
742 				set_current_state(TASK_RUNNING);
743 
744 				ret = (erase->state == MTD_ERASE_FAILED)?-EIO:0;
745 			}
746 			kfree(erase);
747 		}
748 		break;
749 	}
750 
751 	case MEMWRITEOOB:
752 	{
753 		struct mtd_oob_buf buf;
754 		struct mtd_oob_buf __user *buf_user = argp;
755 
756 		/* NOTE: writes return length to buf_user->length */
757 		if (copy_from_user(&buf, argp, sizeof(buf)))
758 			ret = -EFAULT;
759 		else
760 			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
761 				buf.ptr, &buf_user->length);
762 		break;
763 	}
764 
765 	case MEMREADOOB:
766 	{
767 		struct mtd_oob_buf buf;
768 		struct mtd_oob_buf __user *buf_user = argp;
769 
770 		/* NOTE: writes return length to buf_user->start */
771 		if (copy_from_user(&buf, argp, sizeof(buf)))
772 			ret = -EFAULT;
773 		else
774 			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
775 				buf.ptr, &buf_user->start);
776 		break;
777 	}
778 
779 	case MEMWRITEOOB64:
780 	{
781 		struct mtd_oob_buf64 buf;
782 		struct mtd_oob_buf64 __user *buf_user = argp;
783 
784 		if (copy_from_user(&buf, argp, sizeof(buf)))
785 			ret = -EFAULT;
786 		else
787 			ret = mtdchar_writeoob(file, mtd, buf.start, buf.length,
788 				(void __user *)(uintptr_t)buf.usr_ptr,
789 				&buf_user->length);
790 		break;
791 	}
792 
793 	case MEMREADOOB64:
794 	{
795 		struct mtd_oob_buf64 buf;
796 		struct mtd_oob_buf64 __user *buf_user = argp;
797 
798 		if (copy_from_user(&buf, argp, sizeof(buf)))
799 			ret = -EFAULT;
800 		else
801 			ret = mtdchar_readoob(file, mtd, buf.start, buf.length,
802 				(void __user *)(uintptr_t)buf.usr_ptr,
803 				&buf_user->length);
804 		break;
805 	}
806 
807 	case MEMWRITE:
808 	{
809 		ret = mtdchar_write_ioctl(mtd,
810 		      (struct mtd_write_req __user *)arg);
811 		break;
812 	}
813 
814 	case MEMLOCK:
815 	{
816 		struct erase_info_user einfo;
817 
818 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
819 			return -EFAULT;
820 
821 		if (!mtd->lock)
822 			ret = -EOPNOTSUPP;
823 		else
824 			ret = mtd->lock(mtd, einfo.start, einfo.length);
825 		break;
826 	}
827 
828 	case MEMUNLOCK:
829 	{
830 		struct erase_info_user einfo;
831 
832 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
833 			return -EFAULT;
834 
835 		if (!mtd->unlock)
836 			ret = -EOPNOTSUPP;
837 		else
838 			ret = mtd->unlock(mtd, einfo.start, einfo.length);
839 		break;
840 	}
841 
842 	case MEMISLOCKED:
843 	{
844 		struct erase_info_user einfo;
845 
846 		if (copy_from_user(&einfo, argp, sizeof(einfo)))
847 			return -EFAULT;
848 
849 		if (!mtd->is_locked)
850 			ret = -EOPNOTSUPP;
851 		else
852 			ret = mtd->is_locked(mtd, einfo.start, einfo.length);
853 		break;
854 	}
855 
856 	/* Legacy interface */
857 	case MEMGETOOBSEL:
858 	{
859 		struct nand_oobinfo oi;
860 
861 		if (!mtd->ecclayout)
862 			return -EOPNOTSUPP;
863 		if (mtd->ecclayout->eccbytes > ARRAY_SIZE(oi.eccpos))
864 			return -EINVAL;
865 
866 		oi.useecc = MTD_NANDECC_AUTOPLACE;
867 		memcpy(&oi.eccpos, mtd->ecclayout->eccpos, sizeof(oi.eccpos));
868 		memcpy(&oi.oobfree, mtd->ecclayout->oobfree,
869 		       sizeof(oi.oobfree));
870 		oi.eccbytes = mtd->ecclayout->eccbytes;
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 		if (!mtd->block_isbad)
884 			ret = -EOPNOTSUPP;
885 		else
886 			return mtd->block_isbad(mtd, offs);
887 		break;
888 	}
889 
890 	case MEMSETBADBLOCK:
891 	{
892 		loff_t offs;
893 
894 		if (copy_from_user(&offs, argp, sizeof(loff_t)))
895 			return -EFAULT;
896 		if (!mtd->block_markbad)
897 			ret = -EOPNOTSUPP;
898 		else
899 			return mtd->block_markbad(mtd, offs);
900 		break;
901 	}
902 
903 #ifdef CONFIG_HAVE_MTD_OTP
904 	case OTPSELECT:
905 	{
906 		int mode;
907 		if (copy_from_user(&mode, argp, sizeof(int)))
908 			return -EFAULT;
909 
910 		mfi->mode = MTD_FILE_MODE_NORMAL;
911 
912 		ret = otp_select_filemode(mfi, mode);
913 
914 		file->f_pos = 0;
915 		break;
916 	}
917 
918 	case OTPGETREGIONCOUNT:
919 	case OTPGETREGIONINFO:
920 	{
921 		struct otp_info *buf = kmalloc(4096, GFP_KERNEL);
922 		if (!buf)
923 			return -ENOMEM;
924 		ret = -EOPNOTSUPP;
925 		switch (mfi->mode) {
926 		case MTD_FILE_MODE_OTP_FACTORY:
927 			if (mtd->get_fact_prot_info)
928 				ret = mtd_get_fact_prot_info(mtd, buf, 4096);
929 			break;
930 		case MTD_FILE_MODE_OTP_USER:
931 			if (mtd->get_user_prot_info)
932 				ret = mtd->get_user_prot_info(mtd, buf, 4096);
933 			break;
934 		default:
935 			break;
936 		}
937 		if (ret >= 0) {
938 			if (cmd == OTPGETREGIONCOUNT) {
939 				int nbr = ret / sizeof(struct otp_info);
940 				ret = copy_to_user(argp, &nbr, sizeof(int));
941 			} else
942 				ret = copy_to_user(argp, buf, ret);
943 			if (ret)
944 				ret = -EFAULT;
945 		}
946 		kfree(buf);
947 		break;
948 	}
949 
950 	case OTPLOCK:
951 	{
952 		struct otp_info oinfo;
953 
954 		if (mfi->mode != MTD_FILE_MODE_OTP_USER)
955 			return -EINVAL;
956 		if (copy_from_user(&oinfo, argp, sizeof(oinfo)))
957 			return -EFAULT;
958 		if (!mtd->lock_user_prot_reg)
959 			return -EOPNOTSUPP;
960 		ret = mtd->lock_user_prot_reg(mtd, oinfo.start, oinfo.length);
961 		break;
962 	}
963 #endif
964 
965 	/* This ioctl is being deprecated - it truncates the ECC layout */
966 	case ECCGETLAYOUT:
967 	{
968 		struct nand_ecclayout_user *usrlay;
969 
970 		if (!mtd->ecclayout)
971 			return -EOPNOTSUPP;
972 
973 		usrlay = kmalloc(sizeof(*usrlay), GFP_KERNEL);
974 		if (!usrlay)
975 			return -ENOMEM;
976 
977 		shrink_ecclayout(mtd->ecclayout, usrlay);
978 
979 		if (copy_to_user(argp, usrlay, sizeof(*usrlay)))
980 			ret = -EFAULT;
981 		kfree(usrlay);
982 		break;
983 	}
984 
985 	case ECCGETSTATS:
986 	{
987 		if (copy_to_user(argp, &mtd->ecc_stats,
988 				 sizeof(struct mtd_ecc_stats)))
989 			return -EFAULT;
990 		break;
991 	}
992 
993 	case MTDFILEMODE:
994 	{
995 		mfi->mode = 0;
996 
997 		switch(arg) {
998 		case MTD_FILE_MODE_OTP_FACTORY:
999 		case MTD_FILE_MODE_OTP_USER:
1000 			ret = otp_select_filemode(mfi, arg);
1001 			break;
1002 
1003 		case MTD_FILE_MODE_RAW:
1004 			if (!mtd->read_oob || !mtd->write_oob)
1005 				return -EOPNOTSUPP;
1006 			mfi->mode = arg;
1007 
1008 		case MTD_FILE_MODE_NORMAL:
1009 			break;
1010 		default:
1011 			ret = -EINVAL;
1012 		}
1013 		file->f_pos = 0;
1014 		break;
1015 	}
1016 
1017 	case BLKPG:
1018 	{
1019 		ret = mtdchar_blkpg_ioctl(mtd,
1020 		      (struct blkpg_ioctl_arg __user *)arg);
1021 		break;
1022 	}
1023 
1024 	case BLKRRPART:
1025 	{
1026 		/* No reread partition feature. Just return ok */
1027 		ret = 0;
1028 		break;
1029 	}
1030 
1031 	default:
1032 		ret = -ENOTTY;
1033 	}
1034 
1035 	return ret;
1036 } /* memory_ioctl */
1037 
1038 static long mtdchar_unlocked_ioctl(struct file *file, u_int cmd, u_long arg)
1039 {
1040 	int ret;
1041 
1042 	mutex_lock(&mtd_mutex);
1043 	ret = mtdchar_ioctl(file, cmd, arg);
1044 	mutex_unlock(&mtd_mutex);
1045 
1046 	return ret;
1047 }
1048 
1049 #ifdef CONFIG_COMPAT
1050 
1051 struct mtd_oob_buf32 {
1052 	u_int32_t start;
1053 	u_int32_t length;
1054 	compat_caddr_t ptr;	/* unsigned char* */
1055 };
1056 
1057 #define MEMWRITEOOB32		_IOWR('M', 3, struct mtd_oob_buf32)
1058 #define MEMREADOOB32		_IOWR('M', 4, struct mtd_oob_buf32)
1059 
1060 static long mtdchar_compat_ioctl(struct file *file, unsigned int cmd,
1061 	unsigned long arg)
1062 {
1063 	struct mtd_file_info *mfi = file->private_data;
1064 	struct mtd_info *mtd = mfi->mtd;
1065 	void __user *argp = compat_ptr(arg);
1066 	int ret = 0;
1067 
1068 	mutex_lock(&mtd_mutex);
1069 
1070 	switch (cmd) {
1071 	case MEMWRITEOOB32:
1072 	{
1073 		struct mtd_oob_buf32 buf;
1074 		struct mtd_oob_buf32 __user *buf_user = argp;
1075 
1076 		if (copy_from_user(&buf, argp, sizeof(buf)))
1077 			ret = -EFAULT;
1078 		else
1079 			ret = mtdchar_writeoob(file, mtd, buf.start,
1080 				buf.length, compat_ptr(buf.ptr),
1081 				&buf_user->length);
1082 		break;
1083 	}
1084 
1085 	case MEMREADOOB32:
1086 	{
1087 		struct mtd_oob_buf32 buf;
1088 		struct mtd_oob_buf32 __user *buf_user = argp;
1089 
1090 		/* NOTE: writes return length to buf->start */
1091 		if (copy_from_user(&buf, argp, sizeof(buf)))
1092 			ret = -EFAULT;
1093 		else
1094 			ret = mtdchar_readoob(file, mtd, buf.start,
1095 				buf.length, compat_ptr(buf.ptr),
1096 				&buf_user->start);
1097 		break;
1098 	}
1099 	default:
1100 		ret = mtdchar_ioctl(file, cmd, (unsigned long)argp);
1101 	}
1102 
1103 	mutex_unlock(&mtd_mutex);
1104 
1105 	return ret;
1106 }
1107 
1108 #endif /* CONFIG_COMPAT */
1109 
1110 /*
1111  * try to determine where a shared mapping can be made
1112  * - only supported for NOMMU at the moment (MMU can't doesn't copy private
1113  *   mappings)
1114  */
1115 #ifndef CONFIG_MMU
1116 static unsigned long mtdchar_get_unmapped_area(struct file *file,
1117 					   unsigned long addr,
1118 					   unsigned long len,
1119 					   unsigned long pgoff,
1120 					   unsigned long flags)
1121 {
1122 	struct mtd_file_info *mfi = file->private_data;
1123 	struct mtd_info *mtd = mfi->mtd;
1124 
1125 	if (mtd->get_unmapped_area) {
1126 		unsigned long offset;
1127 
1128 		if (addr != 0)
1129 			return (unsigned long) -EINVAL;
1130 
1131 		if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT))
1132 			return (unsigned long) -EINVAL;
1133 
1134 		offset = pgoff << PAGE_SHIFT;
1135 		if (offset > mtd->size - len)
1136 			return (unsigned long) -EINVAL;
1137 
1138 		return mtd_get_unmapped_area(mtd, len, offset, flags);
1139 	}
1140 
1141 	/* can't map directly */
1142 	return (unsigned long) -ENOSYS;
1143 }
1144 #endif
1145 
1146 /*
1147  * set up a mapping for shared memory segments
1148  */
1149 static int mtdchar_mmap(struct file *file, struct vm_area_struct *vma)
1150 {
1151 #ifdef CONFIG_MMU
1152 	struct mtd_file_info *mfi = file->private_data;
1153 	struct mtd_info *mtd = mfi->mtd;
1154 	struct map_info *map = mtd->priv;
1155 	unsigned long start;
1156 	unsigned long off;
1157 	u32 len;
1158 
1159 	if (mtd->type == MTD_RAM || mtd->type == MTD_ROM) {
1160 		off = vma->vm_pgoff << PAGE_SHIFT;
1161 		start = map->phys;
1162 		len = PAGE_ALIGN((start & ~PAGE_MASK) + map->size);
1163 		start &= PAGE_MASK;
1164 		if ((vma->vm_end - vma->vm_start + off) > len)
1165 			return -EINVAL;
1166 
1167 		off += start;
1168 		vma->vm_pgoff = off >> PAGE_SHIFT;
1169 		vma->vm_flags |= VM_IO | VM_RESERVED;
1170 
1171 #ifdef pgprot_noncached
1172 		if (file->f_flags & O_DSYNC || off >= __pa(high_memory))
1173 			vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1174 #endif
1175 		if (io_remap_pfn_range(vma, vma->vm_start, off >> PAGE_SHIFT,
1176 				       vma->vm_end - vma->vm_start,
1177 				       vma->vm_page_prot))
1178 			return -EAGAIN;
1179 
1180 		return 0;
1181 	}
1182 	return -ENOSYS;
1183 #else
1184 	return vma->vm_flags & VM_SHARED ? 0 : -ENOSYS;
1185 #endif
1186 }
1187 
1188 static const struct file_operations mtd_fops = {
1189 	.owner		= THIS_MODULE,
1190 	.llseek		= mtdchar_lseek,
1191 	.read		= mtdchar_read,
1192 	.write		= mtdchar_write,
1193 	.unlocked_ioctl	= mtdchar_unlocked_ioctl,
1194 #ifdef CONFIG_COMPAT
1195 	.compat_ioctl	= mtdchar_compat_ioctl,
1196 #endif
1197 	.open		= mtdchar_open,
1198 	.release	= mtdchar_close,
1199 	.mmap		= mtdchar_mmap,
1200 #ifndef CONFIG_MMU
1201 	.get_unmapped_area = mtdchar_get_unmapped_area,
1202 #endif
1203 };
1204 
1205 static struct dentry *mtd_inodefs_mount(struct file_system_type *fs_type,
1206 				int flags, const char *dev_name, void *data)
1207 {
1208 	return mount_pseudo(fs_type, "mtd_inode:", NULL, NULL, MTD_INODE_FS_MAGIC);
1209 }
1210 
1211 static struct file_system_type mtd_inodefs_type = {
1212        .name = "mtd_inodefs",
1213        .mount = mtd_inodefs_mount,
1214        .kill_sb = kill_anon_super,
1215 };
1216 
1217 static void mtdchar_notify_add(struct mtd_info *mtd)
1218 {
1219 }
1220 
1221 static void mtdchar_notify_remove(struct mtd_info *mtd)
1222 {
1223 	struct inode *mtd_ino = ilookup(mtd_inode_mnt->mnt_sb, mtd->index);
1224 
1225 	if (mtd_ino) {
1226 		/* Destroy the inode if it exists */
1227 		clear_nlink(mtd_ino);
1228 		iput(mtd_ino);
1229 	}
1230 }
1231 
1232 static struct mtd_notifier mtdchar_notifier = {
1233 	.add = mtdchar_notify_add,
1234 	.remove = mtdchar_notify_remove,
1235 };
1236 
1237 static int __init init_mtdchar(void)
1238 {
1239 	int ret;
1240 
1241 	ret = __register_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS,
1242 				   "mtd", &mtd_fops);
1243 	if (ret < 0) {
1244 		pr_notice("Can't allocate major number %d for "
1245 				"Memory Technology Devices.\n", MTD_CHAR_MAJOR);
1246 		return ret;
1247 	}
1248 
1249 	ret = register_filesystem(&mtd_inodefs_type);
1250 	if (ret) {
1251 		pr_notice("Can't register mtd_inodefs filesystem: %d\n", ret);
1252 		goto err_unregister_chdev;
1253 	}
1254 
1255 	mtd_inode_mnt = kern_mount(&mtd_inodefs_type);
1256 	if (IS_ERR(mtd_inode_mnt)) {
1257 		ret = PTR_ERR(mtd_inode_mnt);
1258 		pr_notice("Error mounting mtd_inodefs filesystem: %d\n", ret);
1259 		goto err_unregister_filesystem;
1260 	}
1261 	register_mtd_user(&mtdchar_notifier);
1262 
1263 	return ret;
1264 
1265 err_unregister_filesystem:
1266 	unregister_filesystem(&mtd_inodefs_type);
1267 err_unregister_chdev:
1268 	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1269 	return ret;
1270 }
1271 
1272 static void __exit cleanup_mtdchar(void)
1273 {
1274 	unregister_mtd_user(&mtdchar_notifier);
1275 	kern_unmount(mtd_inode_mnt);
1276 	unregister_filesystem(&mtd_inodefs_type);
1277 	__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
1278 }
1279 
1280 module_init(init_mtdchar);
1281 module_exit(cleanup_mtdchar);
1282 
1283 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);
1284 
1285 MODULE_LICENSE("GPL");
1286 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
1287 MODULE_DESCRIPTION("Direct character-device access to MTD devices");
1288 MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR);
1289