xref: /openbmc/linux/drivers/mtd/mtdconcat.c (revision 9ee67182)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * MTD device concatenation layer
4  *
5  * Copyright © 2002 Robert Kaiser <rkaiser@sysgo.de>
6  * Copyright © 2002-2010 David Woodhouse <dwmw2@infradead.org>
7  *
8  * NAND support by Christian Gan <cgan@iders.ca>
9  */
10 
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/sched.h>
15 #include <linux/types.h>
16 #include <linux/backing-dev.h>
17 
18 #include <linux/mtd/mtd.h>
19 #include <linux/mtd/concat.h>
20 
21 #include <asm/div64.h>
22 
23 /*
24  * Our storage structure:
25  * Subdev points to an array of pointers to struct mtd_info objects
26  * which is allocated along with this structure
27  *
28  */
29 struct mtd_concat {
30 	struct mtd_info mtd;
31 	int num_subdev;
32 	struct mtd_info **subdev;
33 };
34 
35 /*
36  * how to calculate the size required for the above structure,
37  * including the pointer array subdev points to:
38  */
39 #define SIZEOF_STRUCT_MTD_CONCAT(num_subdev)	\
40 	((sizeof(struct mtd_concat) + (num_subdev) * sizeof(struct mtd_info *)))
41 
42 /*
43  * Given a pointer to the MTD object in the mtd_concat structure,
44  * we can retrieve the pointer to that structure with this macro.
45  */
46 #define CONCAT(x)  ((struct mtd_concat *)(x))
47 
48 /*
49  * MTD methods which look up the relevant subdevice, translate the
50  * effective address and pass through to the subdevice.
51  */
52 
53 static int
concat_read(struct mtd_info * mtd,loff_t from,size_t len,size_t * retlen,u_char * buf)54 concat_read(struct mtd_info *mtd, loff_t from, size_t len,
55 	    size_t * retlen, u_char * buf)
56 {
57 	struct mtd_concat *concat = CONCAT(mtd);
58 	int ret = 0, err;
59 	int i;
60 
61 	for (i = 0; i < concat->num_subdev; i++) {
62 		struct mtd_info *subdev = concat->subdev[i];
63 		size_t size, retsize;
64 
65 		if (from >= subdev->size) {
66 			/* Not destined for this subdev */
67 			size = 0;
68 			from -= subdev->size;
69 			continue;
70 		}
71 		if (from + len > subdev->size)
72 			/* First part goes into this subdev */
73 			size = subdev->size - from;
74 		else
75 			/* Entire transaction goes into this subdev */
76 			size = len;
77 
78 		err = mtd_read(subdev, from, size, &retsize, buf);
79 
80 		/* Save information about bitflips! */
81 		if (unlikely(err)) {
82 			if (mtd_is_eccerr(err)) {
83 				mtd->ecc_stats.failed++;
84 				ret = err;
85 			} else if (mtd_is_bitflip(err)) {
86 				mtd->ecc_stats.corrected++;
87 				/* Do not overwrite -EBADMSG !! */
88 				if (!ret)
89 					ret = err;
90 			} else
91 				return err;
92 		}
93 
94 		*retlen += retsize;
95 		len -= size;
96 		if (len == 0)
97 			return ret;
98 
99 		buf += size;
100 		from = 0;
101 	}
102 	return -EINVAL;
103 }
104 
105 static int
concat_panic_write(struct mtd_info * mtd,loff_t to,size_t len,size_t * retlen,const u_char * buf)106 concat_panic_write(struct mtd_info *mtd, loff_t to, size_t len,
107 	     size_t * retlen, const u_char * buf)
108 {
109 	struct mtd_concat *concat = CONCAT(mtd);
110 	int err = -EINVAL;
111 	int i;
112 	for (i = 0; i < concat->num_subdev; i++) {
113 		struct mtd_info *subdev = concat->subdev[i];
114 		size_t size, retsize;
115 
116 		if (to >= subdev->size) {
117 			to -= subdev->size;
118 			continue;
119 		}
120 		if (to + len > subdev->size)
121 			size = subdev->size - to;
122 		else
123 			size = len;
124 
125 		err = mtd_panic_write(subdev, to, size, &retsize, buf);
126 		if (err == -EOPNOTSUPP) {
127 			printk(KERN_ERR "mtdconcat: Cannot write from panic without panic_write\n");
128 			return err;
129 		}
130 		if (err)
131 			break;
132 
133 		*retlen += retsize;
134 		len -= size;
135 		if (len == 0)
136 			break;
137 
138 		err = -EINVAL;
139 		buf += size;
140 		to = 0;
141 	}
142 	return err;
143 }
144 
145 
146 static int
concat_write(struct mtd_info * mtd,loff_t to,size_t len,size_t * retlen,const u_char * buf)147 concat_write(struct mtd_info *mtd, loff_t to, size_t len,
148 	     size_t * retlen, const u_char * buf)
149 {
150 	struct mtd_concat *concat = CONCAT(mtd);
151 	int err = -EINVAL;
152 	int i;
153 
154 	for (i = 0; i < concat->num_subdev; i++) {
155 		struct mtd_info *subdev = concat->subdev[i];
156 		size_t size, retsize;
157 
158 		if (to >= subdev->size) {
159 			size = 0;
160 			to -= subdev->size;
161 			continue;
162 		}
163 		if (to + len > subdev->size)
164 			size = subdev->size - to;
165 		else
166 			size = len;
167 
168 		err = mtd_write(subdev, to, size, &retsize, buf);
169 		if (err)
170 			break;
171 
172 		*retlen += retsize;
173 		len -= size;
174 		if (len == 0)
175 			break;
176 
177 		err = -EINVAL;
178 		buf += size;
179 		to = 0;
180 	}
181 	return err;
182 }
183 
184 static int
concat_writev(struct mtd_info * mtd,const struct kvec * vecs,unsigned long count,loff_t to,size_t * retlen)185 concat_writev(struct mtd_info *mtd, const struct kvec *vecs,
186 		unsigned long count, loff_t to, size_t * retlen)
187 {
188 	struct mtd_concat *concat = CONCAT(mtd);
189 	struct kvec *vecs_copy;
190 	unsigned long entry_low, entry_high;
191 	size_t total_len = 0;
192 	int i;
193 	int err = -EINVAL;
194 
195 	/* Calculate total length of data */
196 	for (i = 0; i < count; i++)
197 		total_len += vecs[i].iov_len;
198 
199 	/* Check alignment */
200 	if (mtd->writesize > 1) {
201 		uint64_t __to = to;
202 		if (do_div(__to, mtd->writesize) || (total_len % mtd->writesize))
203 			return -EINVAL;
204 	}
205 
206 	/* make a copy of vecs */
207 	vecs_copy = kmemdup(vecs, sizeof(struct kvec) * count, GFP_KERNEL);
208 	if (!vecs_copy)
209 		return -ENOMEM;
210 
211 	entry_low = 0;
212 	for (i = 0; i < concat->num_subdev; i++) {
213 		struct mtd_info *subdev = concat->subdev[i];
214 		size_t size, wsize, retsize, old_iov_len;
215 
216 		if (to >= subdev->size) {
217 			to -= subdev->size;
218 			continue;
219 		}
220 
221 		size = min_t(uint64_t, total_len, subdev->size - to);
222 		wsize = size; /* store for future use */
223 
224 		entry_high = entry_low;
225 		while (entry_high < count) {
226 			if (size <= vecs_copy[entry_high].iov_len)
227 				break;
228 			size -= vecs_copy[entry_high++].iov_len;
229 		}
230 
231 		old_iov_len = vecs_copy[entry_high].iov_len;
232 		vecs_copy[entry_high].iov_len = size;
233 
234 		err = mtd_writev(subdev, &vecs_copy[entry_low],
235 				 entry_high - entry_low + 1, to, &retsize);
236 
237 		vecs_copy[entry_high].iov_len = old_iov_len - size;
238 		vecs_copy[entry_high].iov_base += size;
239 
240 		entry_low = entry_high;
241 
242 		if (err)
243 			break;
244 
245 		*retlen += retsize;
246 		total_len -= wsize;
247 
248 		if (total_len == 0)
249 			break;
250 
251 		err = -EINVAL;
252 		to = 0;
253 	}
254 
255 	kfree(vecs_copy);
256 	return err;
257 }
258 
259 static int
concat_read_oob(struct mtd_info * mtd,loff_t from,struct mtd_oob_ops * ops)260 concat_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
261 {
262 	struct mtd_concat *concat = CONCAT(mtd);
263 	struct mtd_oob_ops devops = *ops;
264 	int i, err, ret = 0;
265 
266 	ops->retlen = ops->oobretlen = 0;
267 
268 	for (i = 0; i < concat->num_subdev; i++) {
269 		struct mtd_info *subdev = concat->subdev[i];
270 
271 		if (from >= subdev->size) {
272 			from -= subdev->size;
273 			continue;
274 		}
275 
276 		/* partial read ? */
277 		if (from + devops.len > subdev->size)
278 			devops.len = subdev->size - from;
279 
280 		err = mtd_read_oob(subdev, from, &devops);
281 		ops->retlen += devops.retlen;
282 		ops->oobretlen += devops.oobretlen;
283 
284 		/* Save information about bitflips! */
285 		if (unlikely(err)) {
286 			if (mtd_is_eccerr(err)) {
287 				mtd->ecc_stats.failed++;
288 				ret = err;
289 			} else if (mtd_is_bitflip(err)) {
290 				mtd->ecc_stats.corrected++;
291 				/* Do not overwrite -EBADMSG !! */
292 				if (!ret)
293 					ret = err;
294 			} else
295 				return err;
296 		}
297 
298 		if (devops.datbuf) {
299 			devops.len = ops->len - ops->retlen;
300 			if (!devops.len)
301 				return ret;
302 			devops.datbuf += devops.retlen;
303 		}
304 		if (devops.oobbuf) {
305 			devops.ooblen = ops->ooblen - ops->oobretlen;
306 			if (!devops.ooblen)
307 				return ret;
308 			devops.oobbuf += ops->oobretlen;
309 		}
310 
311 		from = 0;
312 	}
313 	return -EINVAL;
314 }
315 
316 static int
concat_write_oob(struct mtd_info * mtd,loff_t to,struct mtd_oob_ops * ops)317 concat_write_oob(struct mtd_info *mtd, loff_t to, struct mtd_oob_ops *ops)
318 {
319 	struct mtd_concat *concat = CONCAT(mtd);
320 	struct mtd_oob_ops devops = *ops;
321 	int i, err;
322 
323 	if (!(mtd->flags & MTD_WRITEABLE))
324 		return -EROFS;
325 
326 	ops->retlen = ops->oobretlen = 0;
327 
328 	for (i = 0; i < concat->num_subdev; i++) {
329 		struct mtd_info *subdev = concat->subdev[i];
330 
331 		if (to >= subdev->size) {
332 			to -= subdev->size;
333 			continue;
334 		}
335 
336 		/* partial write ? */
337 		if (to + devops.len > subdev->size)
338 			devops.len = subdev->size - to;
339 
340 		err = mtd_write_oob(subdev, to, &devops);
341 		ops->retlen += devops.retlen;
342 		ops->oobretlen += devops.oobretlen;
343 		if (err)
344 			return err;
345 
346 		if (devops.datbuf) {
347 			devops.len = ops->len - ops->retlen;
348 			if (!devops.len)
349 				return 0;
350 			devops.datbuf += devops.retlen;
351 		}
352 		if (devops.oobbuf) {
353 			devops.ooblen = ops->ooblen - ops->oobretlen;
354 			if (!devops.ooblen)
355 				return 0;
356 			devops.oobbuf += devops.oobretlen;
357 		}
358 		to = 0;
359 	}
360 	return -EINVAL;
361 }
362 
concat_erase(struct mtd_info * mtd,struct erase_info * instr)363 static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
364 {
365 	struct mtd_concat *concat = CONCAT(mtd);
366 	struct mtd_info *subdev;
367 	int i, err;
368 	uint64_t length, offset = 0;
369 	struct erase_info *erase;
370 
371 	/*
372 	 * Check for proper erase block alignment of the to-be-erased area.
373 	 * It is easier to do this based on the super device's erase
374 	 * region info rather than looking at each particular sub-device
375 	 * in turn.
376 	 */
377 	if (!concat->mtd.numeraseregions) {
378 		/* the easy case: device has uniform erase block size */
379 		if (instr->addr & (concat->mtd.erasesize - 1))
380 			return -EINVAL;
381 		if (instr->len & (concat->mtd.erasesize - 1))
382 			return -EINVAL;
383 	} else {
384 		/* device has variable erase size */
385 		struct mtd_erase_region_info *erase_regions =
386 		    concat->mtd.eraseregions;
387 
388 		/*
389 		 * Find the erase region where the to-be-erased area begins:
390 		 */
391 		for (i = 0; i < concat->mtd.numeraseregions &&
392 		     instr->addr >= erase_regions[i].offset; i++) ;
393 		--i;
394 
395 		/*
396 		 * Now erase_regions[i] is the region in which the
397 		 * to-be-erased area begins. Verify that the starting
398 		 * offset is aligned to this region's erase size:
399 		 */
400 		if (i < 0 || instr->addr & (erase_regions[i].erasesize - 1))
401 			return -EINVAL;
402 
403 		/*
404 		 * now find the erase region where the to-be-erased area ends:
405 		 */
406 		for (; i < concat->mtd.numeraseregions &&
407 		     (instr->addr + instr->len) >= erase_regions[i].offset;
408 		     ++i) ;
409 		--i;
410 		/*
411 		 * check if the ending offset is aligned to this region's erase size
412 		 */
413 		if (i < 0 || ((instr->addr + instr->len) &
414 					(erase_regions[i].erasesize - 1)))
415 			return -EINVAL;
416 	}
417 
418 	/* make a local copy of instr to avoid modifying the caller's struct */
419 	erase = kmalloc(sizeof (struct erase_info), GFP_KERNEL);
420 
421 	if (!erase)
422 		return -ENOMEM;
423 
424 	*erase = *instr;
425 	length = instr->len;
426 
427 	/*
428 	 * find the subdevice where the to-be-erased area begins, adjust
429 	 * starting offset to be relative to the subdevice start
430 	 */
431 	for (i = 0; i < concat->num_subdev; i++) {
432 		subdev = concat->subdev[i];
433 		if (subdev->size <= erase->addr) {
434 			erase->addr -= subdev->size;
435 			offset += subdev->size;
436 		} else {
437 			break;
438 		}
439 	}
440 
441 	/* must never happen since size limit has been verified above */
442 	BUG_ON(i >= concat->num_subdev);
443 
444 	/* now do the erase: */
445 	err = 0;
446 	for (; length > 0; i++) {
447 		/* loop for all subdevices affected by this request */
448 		subdev = concat->subdev[i];	/* get current subdevice */
449 
450 		/* limit length to subdevice's size: */
451 		if (erase->addr + length > subdev->size)
452 			erase->len = subdev->size - erase->addr;
453 		else
454 			erase->len = length;
455 
456 		length -= erase->len;
457 		if ((err = mtd_erase(subdev, erase))) {
458 			/* sanity check: should never happen since
459 			 * block alignment has been checked above */
460 			BUG_ON(err == -EINVAL);
461 			if (erase->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
462 				instr->fail_addr = erase->fail_addr + offset;
463 			break;
464 		}
465 		/*
466 		 * erase->addr specifies the offset of the area to be
467 		 * erased *within the current subdevice*. It can be
468 		 * non-zero only the first time through this loop, i.e.
469 		 * for the first subdevice where blocks need to be erased.
470 		 * All the following erases must begin at the start of the
471 		 * current subdevice, i.e. at offset zero.
472 		 */
473 		erase->addr = 0;
474 		offset += subdev->size;
475 	}
476 	kfree(erase);
477 
478 	return err;
479 }
480 
concat_xxlock(struct mtd_info * mtd,loff_t ofs,uint64_t len,bool is_lock)481 static int concat_xxlock(struct mtd_info *mtd, loff_t ofs, uint64_t len,
482 			 bool is_lock)
483 {
484 	struct mtd_concat *concat = CONCAT(mtd);
485 	int i, err = -EINVAL;
486 
487 	for (i = 0; i < concat->num_subdev; i++) {
488 		struct mtd_info *subdev = concat->subdev[i];
489 		uint64_t size;
490 
491 		if (ofs >= subdev->size) {
492 			size = 0;
493 			ofs -= subdev->size;
494 			continue;
495 		}
496 		if (ofs + len > subdev->size)
497 			size = subdev->size - ofs;
498 		else
499 			size = len;
500 
501 		if (is_lock)
502 			err = mtd_lock(subdev, ofs, size);
503 		else
504 			err = mtd_unlock(subdev, ofs, size);
505 		if (err)
506 			break;
507 
508 		len -= size;
509 		if (len == 0)
510 			break;
511 
512 		err = -EINVAL;
513 		ofs = 0;
514 	}
515 
516 	return err;
517 }
518 
concat_lock(struct mtd_info * mtd,loff_t ofs,uint64_t len)519 static int concat_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
520 {
521 	return concat_xxlock(mtd, ofs, len, true);
522 }
523 
concat_unlock(struct mtd_info * mtd,loff_t ofs,uint64_t len)524 static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
525 {
526 	return concat_xxlock(mtd, ofs, len, false);
527 }
528 
concat_is_locked(struct mtd_info * mtd,loff_t ofs,uint64_t len)529 static int concat_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
530 {
531 	struct mtd_concat *concat = CONCAT(mtd);
532 	int i, err = -EINVAL;
533 
534 	for (i = 0; i < concat->num_subdev; i++) {
535 		struct mtd_info *subdev = concat->subdev[i];
536 
537 		if (ofs >= subdev->size) {
538 			ofs -= subdev->size;
539 			continue;
540 		}
541 
542 		if (ofs + len > subdev->size)
543 			break;
544 
545 		return mtd_is_locked(subdev, ofs, len);
546 	}
547 
548 	return err;
549 }
550 
concat_sync(struct mtd_info * mtd)551 static void concat_sync(struct mtd_info *mtd)
552 {
553 	struct mtd_concat *concat = CONCAT(mtd);
554 	int i;
555 
556 	for (i = 0; i < concat->num_subdev; i++) {
557 		struct mtd_info *subdev = concat->subdev[i];
558 		mtd_sync(subdev);
559 	}
560 }
561 
concat_suspend(struct mtd_info * mtd)562 static int concat_suspend(struct mtd_info *mtd)
563 {
564 	struct mtd_concat *concat = CONCAT(mtd);
565 	int i, rc = 0;
566 
567 	for (i = 0; i < concat->num_subdev; i++) {
568 		struct mtd_info *subdev = concat->subdev[i];
569 		if ((rc = mtd_suspend(subdev)) < 0)
570 			return rc;
571 	}
572 	return rc;
573 }
574 
concat_resume(struct mtd_info * mtd)575 static void concat_resume(struct mtd_info *mtd)
576 {
577 	struct mtd_concat *concat = CONCAT(mtd);
578 	int i;
579 
580 	for (i = 0; i < concat->num_subdev; i++) {
581 		struct mtd_info *subdev = concat->subdev[i];
582 		mtd_resume(subdev);
583 	}
584 }
585 
concat_block_isbad(struct mtd_info * mtd,loff_t ofs)586 static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
587 {
588 	struct mtd_concat *concat = CONCAT(mtd);
589 	int i, res = 0;
590 
591 	if (!mtd_can_have_bb(concat->subdev[0]))
592 		return res;
593 
594 	for (i = 0; i < concat->num_subdev; i++) {
595 		struct mtd_info *subdev = concat->subdev[i];
596 
597 		if (ofs >= subdev->size) {
598 			ofs -= subdev->size;
599 			continue;
600 		}
601 
602 		res = mtd_block_isbad(subdev, ofs);
603 		break;
604 	}
605 
606 	return res;
607 }
608 
concat_block_markbad(struct mtd_info * mtd,loff_t ofs)609 static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
610 {
611 	struct mtd_concat *concat = CONCAT(mtd);
612 	int i, err = -EINVAL;
613 
614 	for (i = 0; i < concat->num_subdev; i++) {
615 		struct mtd_info *subdev = concat->subdev[i];
616 
617 		if (ofs >= subdev->size) {
618 			ofs -= subdev->size;
619 			continue;
620 		}
621 
622 		err = mtd_block_markbad(subdev, ofs);
623 		if (!err)
624 			mtd->ecc_stats.badblocks++;
625 		break;
626 	}
627 
628 	return err;
629 }
630 
631 /*
632  * This function constructs a virtual MTD device by concatenating
633  * num_devs MTD devices. A pointer to the new device object is
634  * stored to *new_dev upon success. This function does _not_
635  * register any devices: this is the caller's responsibility.
636  */
mtd_concat_create(struct mtd_info * subdev[],int num_devs,const char * name)637 struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],	/* subdevices to concatenate */
638 				   int num_devs,	/* number of subdevices      */
639 				   const char *name)
640 {				/* name for the new device   */
641 	int i;
642 	size_t size;
643 	struct mtd_concat *concat;
644 	struct mtd_info *subdev_master = NULL;
645 	uint32_t max_erasesize, curr_erasesize;
646 	int num_erase_region;
647 	int max_writebufsize = 0;
648 
649 	printk(KERN_NOTICE "Concatenating MTD devices:\n");
650 	for (i = 0; i < num_devs; i++)
651 		printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
652 	printk(KERN_NOTICE "into device \"%s\"\n", name);
653 
654 	/* allocate the device structure */
655 	size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
656 	concat = kzalloc(size, GFP_KERNEL);
657 	if (!concat) {
658 		printk
659 		    ("memory allocation error while creating concatenated device \"%s\"\n",
660 		     name);
661 		return NULL;
662 	}
663 	concat->subdev = (struct mtd_info **) (concat + 1);
664 
665 	/*
666 	 * Set up the new "super" device's MTD object structure, check for
667 	 * incompatibilities between the subdevices.
668 	 */
669 	concat->mtd.type = subdev[0]->type;
670 	concat->mtd.flags = subdev[0]->flags;
671 	concat->mtd.size = subdev[0]->size;
672 	concat->mtd.erasesize = subdev[0]->erasesize;
673 	concat->mtd.writesize = subdev[0]->writesize;
674 
675 	for (i = 0; i < num_devs; i++)
676 		if (max_writebufsize < subdev[i]->writebufsize)
677 			max_writebufsize = subdev[i]->writebufsize;
678 	concat->mtd.writebufsize = max_writebufsize;
679 
680 	concat->mtd.subpage_sft = subdev[0]->subpage_sft;
681 	concat->mtd.oobsize = subdev[0]->oobsize;
682 	concat->mtd.oobavail = subdev[0]->oobavail;
683 
684 	subdev_master = mtd_get_master(subdev[0]);
685 	if (subdev_master->_writev)
686 		concat->mtd._writev = concat_writev;
687 	if (subdev_master->_read_oob)
688 		concat->mtd._read_oob = concat_read_oob;
689 	if (subdev_master->_write_oob)
690 		concat->mtd._write_oob = concat_write_oob;
691 	if (subdev_master->_block_isbad)
692 		concat->mtd._block_isbad = concat_block_isbad;
693 	if (subdev_master->_block_markbad)
694 		concat->mtd._block_markbad = concat_block_markbad;
695 	if (subdev_master->_panic_write)
696 		concat->mtd._panic_write = concat_panic_write;
697 	if (subdev_master->_read)
698 		concat->mtd._read = concat_read;
699 	if (subdev_master->_write)
700 		concat->mtd._write = concat_write;
701 
702 	concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
703 
704 	concat->subdev[0] = subdev[0];
705 
706 	for (i = 1; i < num_devs; i++) {
707 		if (concat->mtd.type != subdev[i]->type) {
708 			kfree(concat);
709 			printk("Incompatible device type on \"%s\"\n",
710 			       subdev[i]->name);
711 			return NULL;
712 		}
713 		if (concat->mtd.flags != subdev[i]->flags) {
714 			/*
715 			 * Expect all flags except MTD_WRITEABLE to be
716 			 * equal on all subdevices.
717 			 */
718 			if ((concat->mtd.flags ^ subdev[i]->
719 			     flags) & ~MTD_WRITEABLE) {
720 				kfree(concat);
721 				printk("Incompatible device flags on \"%s\"\n",
722 				       subdev[i]->name);
723 				return NULL;
724 			} else
725 				/* if writeable attribute differs,
726 				   make super device writeable */
727 				concat->mtd.flags |=
728 				    subdev[i]->flags & MTD_WRITEABLE;
729 		}
730 
731 		subdev_master = mtd_get_master(subdev[i]);
732 		concat->mtd.size += subdev[i]->size;
733 		concat->mtd.ecc_stats.badblocks +=
734 			subdev[i]->ecc_stats.badblocks;
735 		if (concat->mtd.writesize   !=  subdev[i]->writesize ||
736 		    concat->mtd.subpage_sft != subdev[i]->subpage_sft ||
737 		    concat->mtd.oobsize    !=  subdev[i]->oobsize ||
738 		    !concat->mtd._read_oob  != !subdev_master->_read_oob ||
739 		    !concat->mtd._write_oob != !subdev_master->_write_oob) {
740 			/*
741 			 * Check against subdev[i] for data members, because
742 			 * subdev's attributes may be different from master
743 			 * mtd device. Check against subdev's master mtd
744 			 * device for callbacks, because the existence of
745 			 * subdev's callbacks is decided by master mtd device.
746 			 */
747 			kfree(concat);
748 			printk("Incompatible OOB or ECC data on \"%s\"\n",
749 			       subdev[i]->name);
750 			return NULL;
751 		}
752 		concat->subdev[i] = subdev[i];
753 
754 	}
755 
756 	mtd_set_ooblayout(&concat->mtd, subdev[0]->ooblayout);
757 
758 	concat->num_subdev = num_devs;
759 	concat->mtd.name = name;
760 
761 	concat->mtd._erase = concat_erase;
762 	concat->mtd._sync = concat_sync;
763 	concat->mtd._lock = concat_lock;
764 	concat->mtd._unlock = concat_unlock;
765 	concat->mtd._is_locked = concat_is_locked;
766 	concat->mtd._suspend = concat_suspend;
767 	concat->mtd._resume = concat_resume;
768 
769 	/*
770 	 * Combine the erase block size info of the subdevices:
771 	 *
772 	 * first, walk the map of the new device and see how
773 	 * many changes in erase size we have
774 	 */
775 	max_erasesize = curr_erasesize = subdev[0]->erasesize;
776 	num_erase_region = 1;
777 	for (i = 0; i < num_devs; i++) {
778 		if (subdev[i]->numeraseregions == 0) {
779 			/* current subdevice has uniform erase size */
780 			if (subdev[i]->erasesize != curr_erasesize) {
781 				/* if it differs from the last subdevice's erase size, count it */
782 				++num_erase_region;
783 				curr_erasesize = subdev[i]->erasesize;
784 				if (curr_erasesize > max_erasesize)
785 					max_erasesize = curr_erasesize;
786 			}
787 		} else {
788 			/* current subdevice has variable erase size */
789 			int j;
790 			for (j = 0; j < subdev[i]->numeraseregions; j++) {
791 
792 				/* walk the list of erase regions, count any changes */
793 				if (subdev[i]->eraseregions[j].erasesize !=
794 				    curr_erasesize) {
795 					++num_erase_region;
796 					curr_erasesize =
797 					    subdev[i]->eraseregions[j].
798 					    erasesize;
799 					if (curr_erasesize > max_erasesize)
800 						max_erasesize = curr_erasesize;
801 				}
802 			}
803 		}
804 	}
805 
806 	if (num_erase_region == 1) {
807 		/*
808 		 * All subdevices have the same uniform erase size.
809 		 * This is easy:
810 		 */
811 		concat->mtd.erasesize = curr_erasesize;
812 		concat->mtd.numeraseregions = 0;
813 	} else {
814 		uint64_t tmp64;
815 
816 		/*
817 		 * erase block size varies across the subdevices: allocate
818 		 * space to store the data describing the variable erase regions
819 		 */
820 		struct mtd_erase_region_info *erase_region_p;
821 		uint64_t begin, position;
822 
823 		concat->mtd.erasesize = max_erasesize;
824 		concat->mtd.numeraseregions = num_erase_region;
825 		concat->mtd.eraseregions = erase_region_p =
826 		    kmalloc_array(num_erase_region,
827 				  sizeof(struct mtd_erase_region_info),
828 				  GFP_KERNEL);
829 		if (!erase_region_p) {
830 			kfree(concat);
831 			printk
832 			    ("memory allocation error while creating erase region list"
833 			     " for device \"%s\"\n", name);
834 			return NULL;
835 		}
836 
837 		/*
838 		 * walk the map of the new device once more and fill in
839 		 * erase region info:
840 		 */
841 		curr_erasesize = subdev[0]->erasesize;
842 		begin = position = 0;
843 		for (i = 0; i < num_devs; i++) {
844 			if (subdev[i]->numeraseregions == 0) {
845 				/* current subdevice has uniform erase size */
846 				if (subdev[i]->erasesize != curr_erasesize) {
847 					/*
848 					 *  fill in an mtd_erase_region_info structure for the area
849 					 *  we have walked so far:
850 					 */
851 					erase_region_p->offset = begin;
852 					erase_region_p->erasesize =
853 					    curr_erasesize;
854 					tmp64 = position - begin;
855 					do_div(tmp64, curr_erasesize);
856 					erase_region_p->numblocks = tmp64;
857 					begin = position;
858 
859 					curr_erasesize = subdev[i]->erasesize;
860 					++erase_region_p;
861 				}
862 				position += subdev[i]->size;
863 			} else {
864 				/* current subdevice has variable erase size */
865 				int j;
866 				for (j = 0; j < subdev[i]->numeraseregions; j++) {
867 					/* walk the list of erase regions, count any changes */
868 					if (subdev[i]->eraseregions[j].
869 					    erasesize != curr_erasesize) {
870 						erase_region_p->offset = begin;
871 						erase_region_p->erasesize =
872 						    curr_erasesize;
873 						tmp64 = position - begin;
874 						do_div(tmp64, curr_erasesize);
875 						erase_region_p->numblocks = tmp64;
876 						begin = position;
877 
878 						curr_erasesize =
879 						    subdev[i]->eraseregions[j].
880 						    erasesize;
881 						++erase_region_p;
882 					}
883 					position +=
884 					    subdev[i]->eraseregions[j].
885 					    numblocks * (uint64_t)curr_erasesize;
886 				}
887 			}
888 		}
889 		/* Now write the final entry */
890 		erase_region_p->offset = begin;
891 		erase_region_p->erasesize = curr_erasesize;
892 		tmp64 = position - begin;
893 		do_div(tmp64, curr_erasesize);
894 		erase_region_p->numblocks = tmp64;
895 	}
896 
897 	return &concat->mtd;
898 }
899 
900 /* Cleans the context obtained from mtd_concat_create() */
mtd_concat_destroy(struct mtd_info * mtd)901 void mtd_concat_destroy(struct mtd_info *mtd)
902 {
903 	struct mtd_concat *concat = CONCAT(mtd);
904 	if (concat->mtd.numeraseregions)
905 		kfree(concat->mtd.eraseregions);
906 	kfree(concat);
907 }
908 
909 EXPORT_SYMBOL(mtd_concat_create);
910 EXPORT_SYMBOL(mtd_concat_destroy);
911 
912 MODULE_LICENSE("GPL");
913 MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
914 MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");
915