xref: /linux/drivers/mtd/ubi/debug.c (revision 0808ebf2f80b962e75741a41ced372a7116f1e26)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (c) International Business Machines Corp., 2006
4  *
5  * Author: Artem Bityutskiy (Битюцкий Артём)
6  */
7 
8 #include "ubi.h"
9 #include <linux/debugfs.h>
10 #include <linux/uaccess.h>
11 #include <linux/module.h>
12 #include <linux/seq_file.h>
13 #include <linux/fault-inject.h>
14 
15 #ifdef CONFIG_MTD_UBI_FAULT_INJECTION
16 static DECLARE_FAULT_ATTR(fault_eccerr_attr);
17 static DECLARE_FAULT_ATTR(fault_bitflips_attr);
18 static DECLARE_FAULT_ATTR(fault_read_failure_attr);
19 static DECLARE_FAULT_ATTR(fault_write_failure_attr);
20 static DECLARE_FAULT_ATTR(fault_erase_failure_attr);
21 static DECLARE_FAULT_ATTR(fault_power_cut_attr);
22 static DECLARE_FAULT_ATTR(fault_io_ff_attr);
23 static DECLARE_FAULT_ATTR(fault_io_ff_bitflips_attr);
24 static DECLARE_FAULT_ATTR(fault_bad_hdr_attr);
25 static DECLARE_FAULT_ATTR(fault_bad_hdr_ebadmsg_attr);
26 
27 #define FAIL_ACTION(name, fault_attr)			\
28 bool should_fail_##name(void)				\
29 {							\
30 	return should_fail(&fault_attr, 1);		\
31 }
32 
33 FAIL_ACTION(eccerr,		fault_eccerr_attr)
34 FAIL_ACTION(bitflips,		fault_bitflips_attr)
35 FAIL_ACTION(read_failure,	fault_read_failure_attr)
36 FAIL_ACTION(write_failure,	fault_write_failure_attr)
37 FAIL_ACTION(erase_failure,	fault_erase_failure_attr)
38 FAIL_ACTION(power_cut,		fault_power_cut_attr)
39 FAIL_ACTION(io_ff,		fault_io_ff_attr)
40 FAIL_ACTION(io_ff_bitflips,	fault_io_ff_bitflips_attr)
41 FAIL_ACTION(bad_hdr,		fault_bad_hdr_attr)
42 FAIL_ACTION(bad_hdr_ebadmsg,	fault_bad_hdr_ebadmsg_attr)
43 #endif
44 
45 /**
46  * ubi_dump_flash - dump a region of flash.
47  * @ubi: UBI device description object
48  * @pnum: the physical eraseblock number to dump
49  * @offset: the starting offset within the physical eraseblock to dump
50  * @len: the length of the region to dump
51  */
52 void ubi_dump_flash(struct ubi_device *ubi, int pnum, int offset, int len)
53 {
54 	int err;
55 	size_t read;
56 	void *buf;
57 	loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
58 
59 	buf = vmalloc(len);
60 	if (!buf)
61 		return;
62 	err = mtd_read(ubi->mtd, addr, len, &read, buf);
63 	if (err && err != -EUCLEAN) {
64 		ubi_err(ubi, "err %d while reading %d bytes from PEB %d:%d, read %zd bytes",
65 			err, len, pnum, offset, read);
66 		goto out;
67 	}
68 
69 	ubi_msg(ubi, "dumping %d bytes of data from PEB %d, offset %d",
70 		len, pnum, offset);
71 	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1, buf, len, 1);
72 out:
73 	vfree(buf);
74 	return;
75 }
76 
77 /**
78  * ubi_dump_ec_hdr - dump an erase counter header.
79  * @ec_hdr: the erase counter header to dump
80  */
81 void ubi_dump_ec_hdr(const struct ubi_ec_hdr *ec_hdr)
82 {
83 	pr_err("Erase counter header dump:\n");
84 	pr_err("\tmagic          %#08x\n", be32_to_cpu(ec_hdr->magic));
85 	pr_err("\tversion        %d\n", (int)ec_hdr->version);
86 	pr_err("\tec             %llu\n", (long long)be64_to_cpu(ec_hdr->ec));
87 	pr_err("\tvid_hdr_offset %d\n", be32_to_cpu(ec_hdr->vid_hdr_offset));
88 	pr_err("\tdata_offset    %d\n", be32_to_cpu(ec_hdr->data_offset));
89 	pr_err("\timage_seq      %d\n", be32_to_cpu(ec_hdr->image_seq));
90 	pr_err("\thdr_crc        %#08x\n", be32_to_cpu(ec_hdr->hdr_crc));
91 	pr_err("erase counter header hexdump:\n");
92 	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
93 		       ec_hdr, UBI_EC_HDR_SIZE, 1);
94 }
95 
96 /**
97  * ubi_dump_vid_hdr - dump a volume identifier header.
98  * @vid_hdr: the volume identifier header to dump
99  */
100 void ubi_dump_vid_hdr(const struct ubi_vid_hdr *vid_hdr)
101 {
102 	pr_err("Volume identifier header dump:\n");
103 	pr_err("\tmagic     %08x\n", be32_to_cpu(vid_hdr->magic));
104 	pr_err("\tversion   %d\n",  (int)vid_hdr->version);
105 	pr_err("\tvol_type  %d\n",  (int)vid_hdr->vol_type);
106 	pr_err("\tcopy_flag %d\n",  (int)vid_hdr->copy_flag);
107 	pr_err("\tcompat    %d\n",  (int)vid_hdr->compat);
108 	pr_err("\tvol_id    %d\n",  be32_to_cpu(vid_hdr->vol_id));
109 	pr_err("\tlnum      %d\n",  be32_to_cpu(vid_hdr->lnum));
110 	pr_err("\tdata_size %d\n",  be32_to_cpu(vid_hdr->data_size));
111 	pr_err("\tused_ebs  %d\n",  be32_to_cpu(vid_hdr->used_ebs));
112 	pr_err("\tdata_pad  %d\n",  be32_to_cpu(vid_hdr->data_pad));
113 	pr_err("\tsqnum     %llu\n",
114 		(unsigned long long)be64_to_cpu(vid_hdr->sqnum));
115 	pr_err("\thdr_crc   %08x\n", be32_to_cpu(vid_hdr->hdr_crc));
116 	pr_err("Volume identifier header hexdump:\n");
117 	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
118 		       vid_hdr, UBI_VID_HDR_SIZE, 1);
119 }
120 
121 /**
122  * ubi_dump_vol_info - dump volume information.
123  * @vol: UBI volume description object
124  */
125 void ubi_dump_vol_info(const struct ubi_volume *vol)
126 {
127 	pr_err("Volume information dump:\n");
128 	pr_err("\tvol_id          %d\n", vol->vol_id);
129 	pr_err("\treserved_pebs   %d\n", vol->reserved_pebs);
130 	pr_err("\talignment       %d\n", vol->alignment);
131 	pr_err("\tdata_pad        %d\n", vol->data_pad);
132 	pr_err("\tvol_type        %d\n", vol->vol_type);
133 	pr_err("\tname_len        %d\n", vol->name_len);
134 	pr_err("\tusable_leb_size %d\n", vol->usable_leb_size);
135 	pr_err("\tused_ebs        %d\n", vol->used_ebs);
136 	pr_err("\tused_bytes      %lld\n", vol->used_bytes);
137 	pr_err("\tlast_eb_bytes   %d\n", vol->last_eb_bytes);
138 	pr_err("\tcorrupted       %d\n", vol->corrupted);
139 	pr_err("\tupd_marker      %d\n", vol->upd_marker);
140 	pr_err("\tskip_check      %d\n", vol->skip_check);
141 
142 	if (vol->name_len <= UBI_VOL_NAME_MAX &&
143 	    strnlen(vol->name, vol->name_len + 1) == vol->name_len) {
144 		pr_err("\tname            %s\n", vol->name);
145 	} else {
146 		pr_err("\t1st 5 characters of name: %c%c%c%c%c\n",
147 		       vol->name[0], vol->name[1], vol->name[2],
148 		       vol->name[3], vol->name[4]);
149 	}
150 }
151 
152 /**
153  * ubi_dump_vtbl_record - dump a &struct ubi_vtbl_record object.
154  * @r: the object to dump
155  * @idx: volume table index
156  */
157 void ubi_dump_vtbl_record(const struct ubi_vtbl_record *r, int idx)
158 {
159 	int name_len = be16_to_cpu(r->name_len);
160 
161 	pr_err("Volume table record %d dump:\n", idx);
162 	pr_err("\treserved_pebs   %d\n", be32_to_cpu(r->reserved_pebs));
163 	pr_err("\talignment       %d\n", be32_to_cpu(r->alignment));
164 	pr_err("\tdata_pad        %d\n", be32_to_cpu(r->data_pad));
165 	pr_err("\tvol_type        %d\n", (int)r->vol_type);
166 	pr_err("\tupd_marker      %d\n", (int)r->upd_marker);
167 	pr_err("\tname_len        %d\n", name_len);
168 
169 	if (r->name[0] == '\0') {
170 		pr_err("\tname            NULL\n");
171 		return;
172 	}
173 
174 	if (name_len <= UBI_VOL_NAME_MAX &&
175 	    strnlen(&r->name[0], name_len + 1) == name_len) {
176 		pr_err("\tname            %s\n", &r->name[0]);
177 	} else {
178 		pr_err("\t1st 5 characters of name: %c%c%c%c%c\n",
179 			r->name[0], r->name[1], r->name[2], r->name[3],
180 			r->name[4]);
181 	}
182 	pr_err("\tcrc             %#08x\n", be32_to_cpu(r->crc));
183 }
184 
185 /**
186  * ubi_dump_av - dump a &struct ubi_ainf_volume object.
187  * @av: the object to dump
188  */
189 void ubi_dump_av(const struct ubi_ainf_volume *av)
190 {
191 	pr_err("Volume attaching information dump:\n");
192 	pr_err("\tvol_id         %d\n", av->vol_id);
193 	pr_err("\thighest_lnum   %d\n", av->highest_lnum);
194 	pr_err("\tleb_count      %d\n", av->leb_count);
195 	pr_err("\tcompat         %d\n", av->compat);
196 	pr_err("\tvol_type       %d\n", av->vol_type);
197 	pr_err("\tused_ebs       %d\n", av->used_ebs);
198 	pr_err("\tlast_data_size %d\n", av->last_data_size);
199 	pr_err("\tdata_pad       %d\n", av->data_pad);
200 }
201 
202 /**
203  * ubi_dump_aeb - dump a &struct ubi_ainf_peb object.
204  * @aeb: the object to dump
205  * @type: object type: 0 - not corrupted, 1 - corrupted
206  */
207 void ubi_dump_aeb(const struct ubi_ainf_peb *aeb, int type)
208 {
209 	pr_err("eraseblock attaching information dump:\n");
210 	pr_err("\tec       %d\n", aeb->ec);
211 	pr_err("\tpnum     %d\n", aeb->pnum);
212 	if (type == 0) {
213 		pr_err("\tlnum     %d\n", aeb->lnum);
214 		pr_err("\tscrub    %d\n", aeb->scrub);
215 		pr_err("\tsqnum    %llu\n", aeb->sqnum);
216 	}
217 }
218 
219 /**
220  * ubi_dump_mkvol_req - dump a &struct ubi_mkvol_req object.
221  * @req: the object to dump
222  */
223 void ubi_dump_mkvol_req(const struct ubi_mkvol_req *req)
224 {
225 	char nm[17];
226 
227 	pr_err("Volume creation request dump:\n");
228 	pr_err("\tvol_id    %d\n",   req->vol_id);
229 	pr_err("\talignment %d\n",   req->alignment);
230 	pr_err("\tbytes     %lld\n", (long long)req->bytes);
231 	pr_err("\tvol_type  %d\n",   req->vol_type);
232 	pr_err("\tname_len  %d\n",   req->name_len);
233 
234 	memcpy(nm, req->name, 16);
235 	nm[16] = 0;
236 	pr_err("\t1st 16 characters of name: %s\n", nm);
237 }
238 
239 /*
240  * Root directory for UBI stuff in debugfs. Contains sub-directories which
241  * contain the stuff specific to particular UBI devices.
242  */
243 static struct dentry *dfs_rootdir;
244 
245 #ifdef CONFIG_MTD_UBI_FAULT_INJECTION
246 static void dfs_create_fault_entry(struct dentry *parent)
247 {
248 	struct dentry *dir;
249 
250 	dir = debugfs_create_dir("fault_inject", parent);
251 	if (IS_ERR_OR_NULL(dir)) {
252 		int err = dir ? PTR_ERR(dir) : -ENODEV;
253 
254 		pr_warn("UBI error: cannot create \"fault_inject\" debugfs directory, error %d\n",
255 			 err);
256 		return;
257 	}
258 
259 	fault_create_debugfs_attr("emulate_eccerr", dir,
260 				  &fault_eccerr_attr);
261 
262 	fault_create_debugfs_attr("emulate_read_failure", dir,
263 				  &fault_read_failure_attr);
264 
265 	fault_create_debugfs_attr("emulate_bitflips", dir,
266 				  &fault_bitflips_attr);
267 
268 	fault_create_debugfs_attr("emulate_write_failure", dir,
269 				  &fault_write_failure_attr);
270 
271 	fault_create_debugfs_attr("emulate_erase_failure", dir,
272 				  &fault_erase_failure_attr);
273 
274 	fault_create_debugfs_attr("emulate_power_cut", dir,
275 				  &fault_power_cut_attr);
276 
277 	fault_create_debugfs_attr("emulate_io_ff", dir,
278 				  &fault_io_ff_attr);
279 
280 	fault_create_debugfs_attr("emulate_io_ff_bitflips", dir,
281 				  &fault_io_ff_bitflips_attr);
282 
283 	fault_create_debugfs_attr("emulate_bad_hdr", dir,
284 				  &fault_bad_hdr_attr);
285 
286 	fault_create_debugfs_attr("emulate_bad_hdr_ebadmsg", dir,
287 				  &fault_bad_hdr_ebadmsg_attr);
288 }
289 #endif
290 
291 /**
292  * ubi_debugfs_init - create UBI debugfs directory.
293  *
294  * Create UBI debugfs directory. Returns zero in case of success and a negative
295  * error code in case of failure.
296  */
297 int ubi_debugfs_init(void)
298 {
299 	if (!IS_ENABLED(CONFIG_DEBUG_FS))
300 		return 0;
301 
302 	dfs_rootdir = debugfs_create_dir("ubi", NULL);
303 	if (IS_ERR_OR_NULL(dfs_rootdir)) {
304 		int err = dfs_rootdir ? PTR_ERR(dfs_rootdir) : -ENODEV;
305 
306 		pr_err("UBI error: cannot create \"ubi\" debugfs directory, error %d\n",
307 		       err);
308 		return err;
309 	}
310 
311 #ifdef CONFIG_MTD_UBI_FAULT_INJECTION
312 	dfs_create_fault_entry(dfs_rootdir);
313 #endif
314 
315 	return 0;
316 }
317 
318 /**
319  * ubi_debugfs_exit - remove UBI debugfs directory.
320  */
321 void ubi_debugfs_exit(void)
322 {
323 	if (IS_ENABLED(CONFIG_DEBUG_FS))
324 		debugfs_remove(dfs_rootdir);
325 }
326 
327 /* Read an UBI debugfs file */
328 static ssize_t dfs_file_read(struct file *file, char __user *user_buf,
329 			     size_t count, loff_t *ppos)
330 {
331 	unsigned long ubi_num = (unsigned long)file->private_data;
332 	struct dentry *dent = file->f_path.dentry;
333 	struct ubi_device *ubi;
334 	struct ubi_debug_info *d;
335 	char buf[16];
336 	int val;
337 
338 	ubi = ubi_get_device(ubi_num);
339 	if (!ubi)
340 		return -ENODEV;
341 	d = &ubi->dbg;
342 
343 	if (dent == d->dfs_chk_gen)
344 		val = d->chk_gen;
345 	else if (dent == d->dfs_chk_io)
346 		val = d->chk_io;
347 	else if (dent == d->dfs_chk_fastmap)
348 		val = d->chk_fastmap;
349 	else if (dent == d->dfs_disable_bgt)
350 		val = d->disable_bgt;
351 	else if (dent == d->dfs_emulate_bitflips)
352 		val = d->emulate_bitflips;
353 	else if (dent == d->dfs_emulate_io_failures)
354 		val = d->emulate_io_failures;
355 	else if (dent == d->dfs_emulate_failures) {
356 		snprintf(buf, sizeof(buf), "0x%04x\n", d->emulate_failures);
357 		count = simple_read_from_buffer(user_buf, count, ppos,
358 						buf, strlen(buf));
359 		goto out;
360 	} else if (dent == d->dfs_emulate_power_cut) {
361 		snprintf(buf, sizeof(buf), "%u\n", d->emulate_power_cut);
362 		count = simple_read_from_buffer(user_buf, count, ppos,
363 						buf, strlen(buf));
364 		goto out;
365 	} else if (dent == d->dfs_power_cut_min) {
366 		snprintf(buf, sizeof(buf), "%u\n", d->power_cut_min);
367 		count = simple_read_from_buffer(user_buf, count, ppos,
368 						buf, strlen(buf));
369 		goto out;
370 	} else if (dent == d->dfs_power_cut_max) {
371 		snprintf(buf, sizeof(buf), "%u\n", d->power_cut_max);
372 		count = simple_read_from_buffer(user_buf, count, ppos,
373 						buf, strlen(buf));
374 		goto out;
375 	} else {
376 		count = -EINVAL;
377 		goto out;
378 	}
379 
380 	if (val)
381 		buf[0] = '1';
382 	else
383 		buf[0] = '0';
384 	buf[1] = '\n';
385 	buf[2] = 0x00;
386 
387 	count = simple_read_from_buffer(user_buf, count, ppos, buf, 2);
388 
389 out:
390 	ubi_put_device(ubi);
391 	return count;
392 }
393 
394 /* Write an UBI debugfs file */
395 static ssize_t dfs_file_write(struct file *file, const char __user *user_buf,
396 			      size_t count, loff_t *ppos)
397 {
398 	unsigned long ubi_num = (unsigned long)file->private_data;
399 	struct dentry *dent = file->f_path.dentry;
400 	struct ubi_device *ubi;
401 	struct ubi_debug_info *d;
402 	size_t buf_size;
403 	char buf[16] = {0};
404 	int val;
405 
406 	ubi = ubi_get_device(ubi_num);
407 	if (!ubi)
408 		return -ENODEV;
409 	d = &ubi->dbg;
410 
411 	buf_size = min_t(size_t, count, (sizeof(buf) - 1));
412 	if (copy_from_user(buf, user_buf, buf_size)) {
413 		count = -EFAULT;
414 		goto out;
415 	}
416 
417 	if (dent == d->dfs_emulate_failures) {
418 		if (kstrtouint(buf, 0, &d->emulate_failures) != 0)
419 			count = -EINVAL;
420 		goto out;
421 	} else if (dent == d->dfs_power_cut_min) {
422 		if (kstrtouint(buf, 0, &d->power_cut_min) != 0)
423 			count = -EINVAL;
424 		goto out;
425 	} else if (dent == d->dfs_power_cut_max) {
426 		if (kstrtouint(buf, 0, &d->power_cut_max) != 0)
427 			count = -EINVAL;
428 		goto out;
429 	} else if (dent == d->dfs_emulate_power_cut) {
430 		if (kstrtoint(buf, 0, &val) != 0)
431 			count = -EINVAL;
432 		else
433 			d->emulate_power_cut = val;
434 		goto out;
435 	}
436 
437 	if (buf[0] == '1')
438 		val = 1;
439 	else if (buf[0] == '0')
440 		val = 0;
441 	else {
442 		count = -EINVAL;
443 		goto out;
444 	}
445 
446 	if (dent == d->dfs_chk_gen)
447 		d->chk_gen = val;
448 	else if (dent == d->dfs_chk_io)
449 		d->chk_io = val;
450 	else if (dent == d->dfs_chk_fastmap)
451 		d->chk_fastmap = val;
452 	else if (dent == d->dfs_disable_bgt)
453 		d->disable_bgt = val;
454 	else if (dent == d->dfs_emulate_bitflips)
455 		d->emulate_bitflips = val;
456 	else if (dent == d->dfs_emulate_io_failures)
457 		d->emulate_io_failures = val;
458 	else
459 		count = -EINVAL;
460 
461 out:
462 	ubi_put_device(ubi);
463 	return count;
464 }
465 
466 /* File operations for all UBI debugfs files except
467  * detailed_erase_block_info
468  */
469 static const struct file_operations dfs_fops = {
470 	.read   = dfs_file_read,
471 	.write  = dfs_file_write,
472 	.open	= simple_open,
473 	.llseek = no_llseek,
474 	.owner  = THIS_MODULE,
475 };
476 
477 /* As long as the position is less then that total number of erase blocks,
478  * we still have more to print.
479  */
480 static void *eraseblk_count_seq_start(struct seq_file *s, loff_t *pos)
481 {
482 	struct ubi_device *ubi = s->private;
483 
484 	if (*pos < ubi->peb_count)
485 		return pos;
486 
487 	return NULL;
488 }
489 
490 /* Since we are using the position as the iterator, we just need to check if we
491  * are done and increment the position.
492  */
493 static void *eraseblk_count_seq_next(struct seq_file *s, void *v, loff_t *pos)
494 {
495 	struct ubi_device *ubi = s->private;
496 
497 	(*pos)++;
498 
499 	if (*pos < ubi->peb_count)
500 		return pos;
501 
502 	return NULL;
503 }
504 
505 static void eraseblk_count_seq_stop(struct seq_file *s, void *v)
506 {
507 }
508 
509 static int eraseblk_count_seq_show(struct seq_file *s, void *iter)
510 {
511 	struct ubi_device *ubi = s->private;
512 	struct ubi_wl_entry *wl;
513 	int *block_number = iter;
514 	int erase_count = -1;
515 	int err;
516 
517 	/* If this is the start, print a header */
518 	if (*block_number == 0)
519 		seq_puts(s, "physical_block_number\terase_count\n");
520 
521 	err = ubi_io_is_bad(ubi, *block_number);
522 	if (err)
523 		return err;
524 
525 	spin_lock(&ubi->wl_lock);
526 
527 	wl = ubi->lookuptbl[*block_number];
528 	if (wl)
529 		erase_count = wl->ec;
530 
531 	spin_unlock(&ubi->wl_lock);
532 
533 	if (erase_count < 0)
534 		return 0;
535 
536 	seq_printf(s, "%-22d\t%-11d\n", *block_number, erase_count);
537 
538 	return 0;
539 }
540 
541 static const struct seq_operations eraseblk_count_seq_ops = {
542 	.start = eraseblk_count_seq_start,
543 	.next = eraseblk_count_seq_next,
544 	.stop = eraseblk_count_seq_stop,
545 	.show = eraseblk_count_seq_show
546 };
547 
548 static int eraseblk_count_open(struct inode *inode, struct file *f)
549 {
550 	struct seq_file *s;
551 	int err;
552 
553 	err = seq_open(f, &eraseblk_count_seq_ops);
554 	if (err)
555 		return err;
556 
557 	s = f->private_data;
558 	s->private = ubi_get_device((unsigned long)inode->i_private);
559 
560 	if (!s->private)
561 		return -ENODEV;
562 	else
563 		return 0;
564 }
565 
566 static int eraseblk_count_release(struct inode *inode, struct file *f)
567 {
568 	struct seq_file *s = f->private_data;
569 	struct ubi_device *ubi = s->private;
570 
571 	ubi_put_device(ubi);
572 
573 	return seq_release(inode, f);
574 }
575 
576 static const struct file_operations eraseblk_count_fops = {
577 	.owner = THIS_MODULE,
578 	.open = eraseblk_count_open,
579 	.read = seq_read,
580 	.llseek = seq_lseek,
581 	.release = eraseblk_count_release,
582 };
583 
584 /**
585  * ubi_debugfs_init_dev - initialize debugfs for an UBI device.
586  * @ubi: UBI device description object
587  *
588  * This function creates all debugfs files for UBI device @ubi. Returns zero in
589  * case of success and a negative error code in case of failure.
590  */
591 int ubi_debugfs_init_dev(struct ubi_device *ubi)
592 {
593 	unsigned long ubi_num = ubi->ubi_num;
594 	struct ubi_debug_info *d = &ubi->dbg;
595 	umode_t mode = S_IRUSR | S_IWUSR;
596 	int n;
597 
598 	if (!IS_ENABLED(CONFIG_DEBUG_FS))
599 		return 0;
600 
601 	n = snprintf(d->dfs_dir_name, UBI_DFS_DIR_LEN, UBI_DFS_DIR_NAME,
602 		     ubi->ubi_num);
603 	if (n >= UBI_DFS_DIR_LEN) {
604 		/* The array size is too small */
605 		return -EINVAL;
606 	}
607 
608 	d->dfs_dir = debugfs_create_dir(d->dfs_dir_name, dfs_rootdir);
609 
610 	d->dfs_chk_gen = debugfs_create_file("chk_gen", mode, d->dfs_dir,
611 					     (void *)ubi_num, &dfs_fops);
612 
613 	d->dfs_chk_io = debugfs_create_file("chk_io", mode, d->dfs_dir,
614 					    (void *)ubi_num, &dfs_fops);
615 
616 	d->dfs_chk_fastmap = debugfs_create_file("chk_fastmap", mode,
617 						 d->dfs_dir, (void *)ubi_num,
618 						 &dfs_fops);
619 
620 	d->dfs_disable_bgt = debugfs_create_file("tst_disable_bgt", mode,
621 						 d->dfs_dir, (void *)ubi_num,
622 						 &dfs_fops);
623 
624 	d->dfs_emulate_bitflips = debugfs_create_file("tst_emulate_bitflips",
625 						      mode, d->dfs_dir,
626 						      (void *)ubi_num,
627 						      &dfs_fops);
628 
629 	d->dfs_emulate_io_failures = debugfs_create_file("tst_emulate_io_failures",
630 							 mode, d->dfs_dir,
631 							 (void *)ubi_num,
632 							 &dfs_fops);
633 
634 	d->dfs_emulate_power_cut = debugfs_create_file("tst_emulate_power_cut",
635 						       mode, d->dfs_dir,
636 						       (void *)ubi_num,
637 						       &dfs_fops);
638 
639 	d->dfs_power_cut_min = debugfs_create_file("tst_emulate_power_cut_min",
640 						   mode, d->dfs_dir,
641 						   (void *)ubi_num, &dfs_fops);
642 
643 	d->dfs_power_cut_max = debugfs_create_file("tst_emulate_power_cut_max",
644 						   mode, d->dfs_dir,
645 						   (void *)ubi_num, &dfs_fops);
646 
647 	debugfs_create_file("detailed_erase_block_info", S_IRUSR, d->dfs_dir,
648 			    (void *)ubi_num, &eraseblk_count_fops);
649 
650 #ifdef CONFIG_MTD_UBI_FAULT_INJECTION
651 	d->dfs_emulate_failures = debugfs_create_file("emulate_failures",
652 						       mode, d->dfs_dir,
653 						       (void *)ubi_num,
654 						       &dfs_fops);
655 #endif
656 	return 0;
657 }
658 
659 /**
660  * ubi_debugfs_exit_dev - free all debugfs files corresponding to device @ubi
661  * @ubi: UBI device description object
662  */
663 void ubi_debugfs_exit_dev(struct ubi_device *ubi)
664 {
665 	if (IS_ENABLED(CONFIG_DEBUG_FS))
666 		debugfs_remove_recursive(ubi->dbg.dfs_dir);
667 }
668 
669 /**
670  * ubi_dbg_power_cut - emulate a power cut if it is time to do so
671  * @ubi: UBI device description object
672  * @caller: Flags set to indicate from where the function is being called
673  *
674  * Returns non-zero if a power cut was emulated, zero if not.
675  */
676 int ubi_dbg_power_cut(struct ubi_device *ubi, int caller)
677 {
678 	unsigned int range;
679 
680 	if ((ubi->dbg.emulate_power_cut & caller) == 0)
681 		return 0;
682 
683 	if (ubi->dbg.power_cut_counter == 0) {
684 		ubi->dbg.power_cut_counter = ubi->dbg.power_cut_min;
685 
686 		if (ubi->dbg.power_cut_max > ubi->dbg.power_cut_min) {
687 			range = ubi->dbg.power_cut_max - ubi->dbg.power_cut_min;
688 			ubi->dbg.power_cut_counter += get_random_u32_below(range);
689 		}
690 		return 0;
691 	}
692 
693 	ubi->dbg.power_cut_counter--;
694 	if (ubi->dbg.power_cut_counter)
695 		return 0;
696 
697 	return 1;
698 }
699