drivers/mtd/ubi/debug.c

   1 /*
   2  * Copyright (c) International Business Machines Corp., 2006
   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
  12  * the 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  17  *
  18  * Author: Artem Bityutskiy (Битюцкий Артём)
  19  */
  20
  21 #include "ubi.h"
  22 #include <linux/debugfs.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/module.h>
  25 #include <linux/seq_file.h>
  26
  27
  28 /**
  29  * ubi_dump_flash - dump a region of flash.
  30  * @ubi: UBI device description object
  31  * @pnum: the physical eraseblock number to dump
  32  * @offset: the starting offset within the physical eraseblock to dump
  33  * @len: the length of the region to dump
  34  */
  35 void ubi_dump_flash(struct ubi_device *ubi, int pnum, int offset, int len)
  36 {
  37         int err;
  38         size_t read;
  39         void *buf;
  40         loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
  41
  42         buf = vmalloc(len);
  43         if (!buf)
  44                 return;
  45         err = mtd_read(ubi->mtd, addr, len, &read, buf);
  46         if (err && err != -EUCLEAN) {
  47                 ubi_err(ubi, "err %d while reading %d bytes from PEB %d:%d, read %zd bytes",
  48                         err, len, pnum, offset, read);
  49                 goto out;
  50         }
  51
  52         ubi_msg(ubi, "dumping %d bytes of data from PEB %d, offset %d",
  53                 len, pnum, offset);
  54         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1, buf, len, 1);
  55 out:
  56         vfree(buf);
  57         return;
  58 }
  59
  60 /**
  61  * ubi_dump_ec_hdr - dump an erase counter header.
  62  * @ec_hdr: the erase counter header to dump
  63  */
  64 void ubi_dump_ec_hdr(const struct ubi_ec_hdr *ec_hdr)
  65 {
  66         pr_err("Erase counter header dump:\n");
  67         pr_err("\tmagic          %#08x\n", be32_to_cpu(ec_hdr->magic));
  68         pr_err("\tversion        %d\n", (int)ec_hdr->version);
  69         pr_err("\tec             %llu\n", (long long)be64_to_cpu(ec_hdr->ec));
  70         pr_err("\tvid_hdr_offset %d\n", be32_to_cpu(ec_hdr->vid_hdr_offset));
  71         pr_err("\tdata_offset    %d\n", be32_to_cpu(ec_hdr->data_offset));
  72         pr_err("\timage_seq      %d\n", be32_to_cpu(ec_hdr->image_seq));
  73         pr_err("\thdr_crc        %#08x\n", be32_to_cpu(ec_hdr->hdr_crc));
  74         pr_err("erase counter header hexdump:\n");
  75         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
  76                        ec_hdr, UBI_EC_HDR_SIZE, 1);
  77 }
  78
  79 /**
  80  * ubi_dump_vid_hdr - dump a volume identifier header.
  81  * @vid_hdr: the volume identifier header to dump
  82  */
  83 void ubi_dump_vid_hdr(const struct ubi_vid_hdr *vid_hdr)
  84 {
  85         pr_err("Volume identifier header dump:\n");
  86         pr_err("\tmagic     %08x\n", be32_to_cpu(vid_hdr->magic));
  87         pr_err("\tversion   %d\n",  (int)vid_hdr->version);
  88         pr_err("\tvol_type  %d\n",  (int)vid_hdr->vol_type);
  89         pr_err("\tcopy_flag %d\n",  (int)vid_hdr->copy_flag);
  90         pr_err("\tcompat    %d\n",  (int)vid_hdr->compat);
  91         pr_err("\tvol_id    %d\n",  be32_to_cpu(vid_hdr->vol_id));
  92         pr_err("\tlnum      %d\n",  be32_to_cpu(vid_hdr->lnum));
  93         pr_err("\tdata_size %d\n",  be32_to_cpu(vid_hdr->data_size));
  94         pr_err("\tused_ebs  %d\n",  be32_to_cpu(vid_hdr->used_ebs));
  95         pr_err("\tdata_pad  %d\n",  be32_to_cpu(vid_hdr->data_pad));
  96         pr_err("\tsqnum     %llu\n",
  97                 (unsigned long long)be64_to_cpu(vid_hdr->sqnum));
  98         pr_err("\thdr_crc   %08x\n", be32_to_cpu(vid_hdr->hdr_crc));
  99         pr_err("Volume identifier header hexdump:\n");
 100         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1,
 101                        vid_hdr, UBI_VID_HDR_SIZE, 1);
 102 }
 103
 104 /**
 105  * ubi_dump_vol_info - dump volume information.
 106  * @vol: UBI volume description object
 107  */
 108 void ubi_dump_vol_info(const struct ubi_volume *vol)
 109 {
 110         pr_err("Volume information dump:\n");
 111         pr_err("\tvol_id          %d\n", vol->vol_id);
 112         pr_err("\treserved_pebs   %d\n", vol->reserved_pebs);
 113         pr_err("\talignment       %d\n", vol->alignment);
 114         pr_err("\tdata_pad        %d\n", vol->data_pad);
 115         pr_err("\tvol_type        %d\n", vol->vol_type);
 116         pr_err("\tname_len        %d\n", vol->name_len);
 117         pr_err("\tusable_leb_size %d\n", vol->usable_leb_size);
 118         pr_err("\tused_ebs        %d\n", vol->used_ebs);
 119         pr_err("\tused_bytes      %lld\n", vol->used_bytes);
 120         pr_err("\tlast_eb_bytes   %d\n", vol->last_eb_bytes);
 121         pr_err("\tcorrupted       %d\n", vol->corrupted);
 122         pr_err("\tupd_marker      %d\n", vol->upd_marker);
 123
 124         if (vol->name_len <= UBI_VOL_NAME_MAX &&
 125             strnlen(vol->name, vol->name_len + 1) == vol->name_len) {
 126                 pr_err("\tname            %s\n", vol->name);
 127         } else {
 128                 pr_err("\t1st 5 characters of name: %c%c%c%c%c\n",
 129                        vol->name[0], vol->name[1], vol->name[2],
 130                        vol->name[3], vol->name[4]);
 131         }
 132 }
 133
 134 /**
 135  * ubi_dump_vtbl_record - dump a &struct ubi_vtbl_record object.
 136  * @r: the object to dump
 137  * @idx: volume table index
 138  */
 139 void ubi_dump_vtbl_record(const struct ubi_vtbl_record *r, int idx)
 140 {
 141         int name_len = be16_to_cpu(r->name_len);
 142
 143         pr_err("Volume table record %d dump:\n", idx);
 144         pr_err("\treserved_pebs   %d\n", be32_to_cpu(r->reserved_pebs));
 145         pr_err("\talignment       %d\n", be32_to_cpu(r->alignment));
 146         pr_err("\tdata_pad        %d\n", be32_to_cpu(r->data_pad));
 147         pr_err("\tvol_type        %d\n", (int)r->vol_type);
 148         pr_err("\tupd_marker      %d\n", (int)r->upd_marker);
 149         pr_err("\tname_len        %d\n", name_len);
 150
 151         if (r->name[0] == '\0') {
 152                 pr_err("\tname            NULL\n");
 153                 return;
 154         }
 155
 156         if (name_len <= UBI_VOL_NAME_MAX &&
 157             strnlen(&r->name[0], name_len + 1) == name_len) {
 158                 pr_err("\tname            %s\n", &r->name[0]);
 159         } else {
 160                 pr_err("\t1st 5 characters of name: %c%c%c%c%c\n",
 161                         r->name[0], r->name[1], r->name[2], r->name[3],
 162                         r->name[4]);
 163         }
 164         pr_err("\tcrc             %#08x\n", be32_to_cpu(r->crc));
 165 }
 166
 167 /**
 168  * ubi_dump_av - dump a &struct ubi_ainf_volume object.
 169  * @av: the object to dump
 170  */
 171 void ubi_dump_av(const struct ubi_ainf_volume *av)
 172 {
 173         pr_err("Volume attaching information dump:\n");
 174         pr_err("\tvol_id         %d\n", av->vol_id);
 175         pr_err("\thighest_lnum   %d\n", av->highest_lnum);
 176         pr_err("\tleb_count      %d\n", av->leb_count);
 177         pr_err("\tcompat         %d\n", av->compat);
 178         pr_err("\tvol_type       %d\n", av->vol_type);
 179         pr_err("\tused_ebs       %d\n", av->used_ebs);
 180         pr_err("\tlast_data_size %d\n", av->last_data_size);
 181         pr_err("\tdata_pad       %d\n", av->data_pad);
 182 }
 183
 184 /**
 185  * ubi_dump_aeb - dump a &struct ubi_ainf_peb object.
 186  * @aeb: the object to dump
 187  * @type: object type: 0 - not corrupted, 1 - corrupted
 188  */
 189 void ubi_dump_aeb(const struct ubi_ainf_peb *aeb, int type)
 190 {
 191         pr_err("eraseblock attaching information dump:\n");
 192         pr_err("\tec       %d\n", aeb->ec);
 193         pr_err("\tpnum     %d\n", aeb->pnum);
 194         if (type == 0) {
 195                 pr_err("\tlnum     %d\n", aeb->lnum);
 196                 pr_err("\tscrub    %d\n", aeb->scrub);
 197                 pr_err("\tsqnum    %llu\n", aeb->sqnum);
 198         }
 199 }
 200
 201 /**
 202  * ubi_dump_mkvol_req - dump a &struct ubi_mkvol_req object.
 203  * @req: the object to dump
 204  */
 205 void ubi_dump_mkvol_req(const struct ubi_mkvol_req *req)
 206 {
 207         char nm[17];
 208
 209         pr_err("Volume creation request dump:\n");
 210         pr_err("\tvol_id    %d\n",   req->vol_id);
 211         pr_err("\talignment %d\n",   req->alignment);
 212         pr_err("\tbytes     %lld\n", (long long)req->bytes);
 213         pr_err("\tvol_type  %d\n",   req->vol_type);
 214         pr_err("\tname_len  %d\n",   req->name_len);
 215
 216         memcpy(nm, req->name, 16);
 217         nm[16] = 0;
 218         pr_err("\t1st 16 characters of name: %s\n", nm);
 219 }
 220
 221 /*
 222  * Root directory for UBI stuff in debugfs. Contains sub-directories which
 223  * contain the stuff specific to particular UBI devices.
 224  */
 225 static struct dentry *dfs_rootdir;
 226
 227 /**
 228  * ubi_debugfs_init - create UBI debugfs directory.
 229  *
 230  * Create UBI debugfs directory. Returns zero in case of success and a negative
 231  * error code in case of failure.
 232  */
 233 int ubi_debugfs_init(void)
 234 {
 235         if (!IS_ENABLED(CONFIG_DEBUG_FS))
 236                 return 0;
 237
 238         dfs_rootdir = debugfs_create_dir("ubi", NULL);
 239         if (IS_ERR_OR_NULL(dfs_rootdir)) {
 240                 int err = dfs_rootdir ? PTR_ERR(dfs_rootdir) : -ENODEV;
 241
 242                 pr_err("UBI error: cannot create \"ubi\" debugfs directory, error %d\n",
 243                        err);
 244                 return err;
 245         }
 246
 247         return 0;
 248 }
 249
 250 /**
 251  * ubi_debugfs_exit - remove UBI debugfs directory.
 252  */
 253 void ubi_debugfs_exit(void)
 254 {
 255         if (IS_ENABLED(CONFIG_DEBUG_FS))
 256                 debugfs_remove(dfs_rootdir);
 257 }
 258
 259 /* Read an UBI debugfs file */
 260 static ssize_t dfs_file_read(struct file *file, char __user *user_buf,
 261                              size_t count, loff_t *ppos)
 262 {
 263         unsigned long ubi_num = (unsigned long)file->private_data;
 264         struct dentry *dent = file->f_path.dentry;
 265         struct ubi_device *ubi;
 266         struct ubi_debug_info *d;
 267         char buf[8];
 268         int val;
 269
 270         ubi = ubi_get_device(ubi_num);
 271         if (!ubi)
 272                 return -ENODEV;
 273         d = &ubi->dbg;
 274
 275         if (dent == d->dfs_chk_gen)
 276                 val = d->chk_gen;
 277         else if (dent == d->dfs_chk_io)
 278                 val = d->chk_io;
 279         else if (dent == d->dfs_chk_fastmap)
 280                 val = d->chk_fastmap;
 281         else if (dent == d->dfs_disable_bgt)
 282                 val = d->disable_bgt;
 283         else if (dent == d->dfs_emulate_bitflips)
 284                 val = d->emulate_bitflips;
 285         else if (dent == d->dfs_emulate_io_failures)
 286                 val = d->emulate_io_failures;
 287         else if (dent == d->dfs_emulate_power_cut) {
 288                 snprintf(buf, sizeof(buf), "%u\n", d->emulate_power_cut);
 289                 count = simple_read_from_buffer(user_buf, count, ppos,
 290                                                 buf, strlen(buf));
 291                 goto out;
 292         } else if (dent == d->dfs_power_cut_min) {
 293                 snprintf(buf, sizeof(buf), "%u\n", d->power_cut_min);
 294                 count = simple_read_from_buffer(user_buf, count, ppos,
 295                                                 buf, strlen(buf));
 296                 goto out;
 297         } else if (dent == d->dfs_power_cut_max) {
 298                 snprintf(buf, sizeof(buf), "%u\n", d->power_cut_max);
 299                 count = simple_read_from_buffer(user_buf, count, ppos,
 300                                                 buf, strlen(buf));
 301                 goto out;
 302         }
 303         else {
 304                 count = -EINVAL;
 305                 goto out;
 306         }
 307
 308         if (val)
 309                 buf[0] = '1';
 310         else
 311                 buf[0] = '0';
 312         buf[1] = '\n';
 313         buf[2] = 0x00;
 314
 315         count = simple_read_from_buffer(user_buf, count, ppos, buf, 2);
 316
 317 out:
 318         ubi_put_device(ubi);
 319         return count;
 320 }
 321
 322 /* Write an UBI debugfs file */
 323 static ssize_t dfs_file_write(struct file *file, const char __user *user_buf,
 324                               size_t count, loff_t *ppos)
 325 {
 326         unsigned long ubi_num = (unsigned long)file->private_data;
 327         struct dentry *dent = file->f_path.dentry;
 328         struct ubi_device *ubi;
 329         struct ubi_debug_info *d;
 330         size_t buf_size;
 331         char buf[8] = {0};
 332         int val;
 333
 334         ubi = ubi_get_device(ubi_num);
 335         if (!ubi)
 336                 return -ENODEV;
 337         d = &ubi->dbg;
 338
 339         buf_size = min_t(size_t, count, (sizeof(buf) - 1));
 340         if (copy_from_user(buf, user_buf, buf_size)) {
 341                 count = -EFAULT;
 342                 goto out;
 343         }
 344
 345         if (dent == d->dfs_power_cut_min) {
 346                 if (kstrtouint(buf, 0, &d->power_cut_min) != 0)
 347                         count = -EINVAL;
 348                 goto out;
 349         } else if (dent == d->dfs_power_cut_max) {
 350                 if (kstrtouint(buf, 0, &d->power_cut_max) != 0)
 351                         count = -EINVAL;
 352                 goto out;
 353         } else if (dent == d->dfs_emulate_power_cut) {
 354                 if (kstrtoint(buf, 0, &val) != 0)
 355                         count = -EINVAL;
 356                 else
 357                         d->emulate_power_cut = val;
 358                 goto out;
 359         }
 360
 361         if (buf[0] == '1')
 362                 val = 1;
 363         else if (buf[0] == '0')
 364                 val = 0;
 365         else {
 366                 count = -EINVAL;
 367                 goto out;
 368         }
 369
 370         if (dent == d->dfs_chk_gen)
 371                 d->chk_gen = val;
 372         else if (dent == d->dfs_chk_io)
 373                 d->chk_io = val;
 374         else if (dent == d->dfs_chk_fastmap)
 375                 d->chk_fastmap = val;
 376         else if (dent == d->dfs_disable_bgt)
 377                 d->disable_bgt = val;
 378         else if (dent == d->dfs_emulate_bitflips)
 379                 d->emulate_bitflips = val;
 380         else if (dent == d->dfs_emulate_io_failures)
 381                 d->emulate_io_failures = val;
 382         else
 383                 count = -EINVAL;
 384
 385 out:
 386         ubi_put_device(ubi);
 387         return count;
 388 }
 389
 390 /* File operations for all UBI debugfs files except
 391  * detailed_erase_block_info
 392  */
 393 static const struct file_operations dfs_fops = {
 394         .read   = dfs_file_read,
 395         .write  = dfs_file_write,
 396         .open   = simple_open,
 397         .llseek = no_llseek,
 398         .owner  = THIS_MODULE,
 399 };
 400
 401 /* As long as the position is less then that total number of erase blocks,
 402  * we still have more to print.
 403  */
 404 static void *eraseblk_count_seq_start(struct seq_file *s, loff_t *pos)
 405 {
 406         struct ubi_device *ubi = s->private;
 407
 408         if (*pos == 0)
 409                 return SEQ_START_TOKEN;
 410
 411         if (*pos < ubi->peb_count)
 412                 return pos;
 413
 414         return NULL;
 415 }
 416
 417 /* Since we are using the position as the iterator, we just need to check if we
 418  * are done and increment the position.
 419  */
 420 static void *eraseblk_count_seq_next(struct seq_file *s, void *v, loff_t *pos)
 421 {
 422         struct ubi_device *ubi = s->private;
 423
 424         if (v == SEQ_START_TOKEN)
 425                 return pos;
 426         (*pos)++;
 427
 428         if (*pos < ubi->peb_count)
 429                 return pos;
 430
 431         return NULL;
 432 }
 433
 434 static void eraseblk_count_seq_stop(struct seq_file *s, void *v)
 435 {
 436 }
 437
 438 static int eraseblk_count_seq_show(struct seq_file *s, void *iter)
 439 {
 440         struct ubi_device *ubi = s->private;
 441         struct ubi_wl_entry *wl;
 442         int *block_number = iter;
 443         int erase_count = -1;
 444         int err;
 445
 446         /* If this is the start, print a header */
 447         if (iter == SEQ_START_TOKEN) {
 448                 seq_puts(s,
 449                          "physical_block_number\terase_count\tblock_status\tread_status\n");
 450                 return 0;
 451         }
 452
 453         err = ubi_io_is_bad(ubi, *block_number);
 454         if (err)
 455                 return err;
 456
 457         spin_lock(&ubi->wl_lock);
 458
 459         wl = ubi->lookuptbl[*block_number];
 460         if (wl)
 461                 erase_count = wl->ec;
 462
 463         spin_unlock(&ubi->wl_lock);
 464
 465         if (erase_count < 0)
 466                 return 0;
 467
 468         seq_printf(s, "%-22d\t%-11d\n", *block_number, erase_count);
 469
 470         return 0;
 471 }
 472
 473 static const struct seq_operations eraseblk_count_seq_ops = {
 474         .start = eraseblk_count_seq_start,
 475         .next = eraseblk_count_seq_next,
 476         .stop = eraseblk_count_seq_stop,
 477         .show = eraseblk_count_seq_show
 478 };
 479
 480 static int eraseblk_count_open(struct inode *inode, struct file *f)
 481 {
 482         struct seq_file *s;
 483         int err;
 484
 485         err = seq_open(f, &eraseblk_count_seq_ops);
 486         if (err)
 487                 return err;
 488
 489         s = f->private_data;
 490         s->private = ubi_get_device((unsigned long)inode->i_private);
 491
 492         if (!s->private)
 493                 return -ENODEV;
 494         else
 495                 return 0;
 496 }
 497
 498 static int eraseblk_count_release(struct inode *inode, struct file *f)
 499 {
 500         struct seq_file *s = f->private_data;
 501         struct ubi_device *ubi = s->private;
 502
 503         ubi_put_device(ubi);
 504
 505         return seq_release(inode, f);
 506 }
 507
 508 static const struct file_operations eraseblk_count_fops = {
 509         .owner = THIS_MODULE,
 510         .open = eraseblk_count_open,
 511         .read = seq_read,
 512         .llseek = seq_lseek,
 513         .release = eraseblk_count_release,
 514 };
 515
 516 /**
 517  * ubi_debugfs_init_dev - initialize debugfs for an UBI device.
 518  * @ubi: UBI device description object
 519  *
 520  * This function creates all debugfs files for UBI device @ubi. Returns zero in
 521  * case of success and a negative error code in case of failure.
 522  */
 523 int ubi_debugfs_init_dev(struct ubi_device *ubi)
 524 {
 525         int err, n;
 526         unsigned long ubi_num = ubi->ubi_num;
 527         const char *fname;
 528         struct dentry *dent;
 529         struct ubi_debug_info *d = &ubi->dbg;
 530
 531         if (!IS_ENABLED(CONFIG_DEBUG_FS))
 532                 return 0;
 533
 534         n = snprintf(d->dfs_dir_name, UBI_DFS_DIR_LEN + 1, UBI_DFS_DIR_NAME,
 535                      ubi->ubi_num);
 536         if (n == UBI_DFS_DIR_LEN) {
 537                 /* The array size is too small */
 538                 fname = UBI_DFS_DIR_NAME;
 539                 dent = ERR_PTR(-EINVAL);
 540                 goto out;
 541         }
 542
 543         fname = d->dfs_dir_name;
 544         dent = debugfs_create_dir(fname, dfs_rootdir);
 545         if (IS_ERR_OR_NULL(dent))
 546                 goto out;
 547         d->dfs_dir = dent;
 548
 549         fname = "chk_gen";
 550         dent = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, (void *)ubi_num,
 551                                    &dfs_fops);
 552         if (IS_ERR_OR_NULL(dent))
 553                 goto out_remove;
 554         d->dfs_chk_gen = dent;
 555
 556         fname = "chk_io";
 557         dent = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, (void *)ubi_num,
 558                                    &dfs_fops);
 559         if (IS_ERR_OR_NULL(dent))
 560                 goto out_remove;
 561         d->dfs_chk_io = dent;
 562
 563         fname = "chk_fastmap";
 564         dent = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, (void *)ubi_num,
 565                                    &dfs_fops);
 566         if (IS_ERR_OR_NULL(dent))
 567                 goto out_remove;
 568         d->dfs_chk_fastmap = dent;
 569
 570         fname = "tst_disable_bgt";
 571         dent = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, (void *)ubi_num,
 572                                    &dfs_fops);
 573         if (IS_ERR_OR_NULL(dent))
 574                 goto out_remove;
 575         d->dfs_disable_bgt = dent;
 576
 577         fname = "tst_emulate_bitflips";
 578         dent = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, (void *)ubi_num,
 579                                    &dfs_fops);
 580         if (IS_ERR_OR_NULL(dent))
 581                 goto out_remove;
 582         d->dfs_emulate_bitflips = dent;
 583
 584         fname = "tst_emulate_io_failures";
 585         dent = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, (void *)ubi_num,
 586                                    &dfs_fops);
 587         if (IS_ERR_OR_NULL(dent))
 588                 goto out_remove;
 589         d->dfs_emulate_io_failures = dent;
 590
 591         fname = "tst_emulate_power_cut";
 592         dent = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, (void *)ubi_num,
 593                                    &dfs_fops);
 594         if (IS_ERR_OR_NULL(dent))
 595                 goto out_remove;
 596         d->dfs_emulate_power_cut = dent;
 597
 598         fname = "tst_emulate_power_cut_min";
 599         dent = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, (void *)ubi_num,
 600                                    &dfs_fops);
 601         if (IS_ERR_OR_NULL(dent))
 602                 goto out_remove;
 603         d->dfs_power_cut_min = dent;
 604
 605         fname = "tst_emulate_power_cut_max";
 606         dent = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, (void *)ubi_num,
 607                                    &dfs_fops);
 608         if (IS_ERR_OR_NULL(dent))
 609                 goto out_remove;
 610         d->dfs_power_cut_max = dent;
 611
 612         fname = "detailed_erase_block_info";
 613         dent = debugfs_create_file(fname, S_IRUSR, d->dfs_dir, (void *)ubi_num,
 614                                    &eraseblk_count_fops);
 615         if (IS_ERR_OR_NULL(dent))
 616                 goto out_remove;
 617
 618         return 0;
 619
 620 out_remove:
 621         debugfs_remove_recursive(d->dfs_dir);
 622 out:
 623         err = dent ? PTR_ERR(dent) : -ENODEV;
 624         ubi_err(ubi, "cannot create \"%s\" debugfs file or directory, error %d\n",
 625                 fname, err);
 626         return err;
 627 }
 628
 629 /**
 630  * dbg_debug_exit_dev - free all debugfs files corresponding to device @ubi
 631  * @ubi: UBI device description object
 632  */
 633 void ubi_debugfs_exit_dev(struct ubi_device *ubi)
 634 {
 635         if (IS_ENABLED(CONFIG_DEBUG_FS))
 636                 debugfs_remove_recursive(ubi->dbg.dfs_dir);
 637 }
 638
 639 /**
 640  * ubi_dbg_power_cut - emulate a power cut if it is time to do so
 641  * @ubi: UBI device description object
 642  * @caller: Flags set to indicate from where the function is being called
 643  *
 644  * Returns non-zero if a power cut was emulated, zero if not.
 645  */
 646 int ubi_dbg_power_cut(struct ubi_device *ubi, int caller)
 647 {
 648         unsigned int range;
 649
 650         if ((ubi->dbg.emulate_power_cut & caller) == 0)
 651                 return 0;
 652
 653         if (ubi->dbg.power_cut_counter == 0) {
 654                 ubi->dbg.power_cut_counter = ubi->dbg.power_cut_min;
 655
 656                 if (ubi->dbg.power_cut_max > ubi->dbg.power_cut_min) {
 657                         range = ubi->dbg.power_cut_max - ubi->dbg.power_cut_min;
 658                         ubi->dbg.power_cut_counter += prandom_u32() % range;
 659                 }
 660                 return 0;
 661         }
 662
 663         ubi->dbg.power_cut_counter--;
 664         if (ubi->dbg.power_cut_counter)
 665                 return 0;
 666
 667         ubi_msg(ubi, "XXXXXXXXXXXXXXX emulating a power cut XXXXXXXXXXXXXXXX");
 668         ubi_ro_mode(ubi);
 669         return 1;
 670 }