drivers/mtd/ubi/build.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
version_show
ubi_volume_notify
ubi_notify_all
ubi_enumerate_volumes
ubi_get_device
ubi_put_device
ubi_get_by_major
ubi_major2num
dev_attribute_show
dev_release
kill_volumes
uif_init
uif_close
ubi_free_internal_volumes
get_bad_peb_limit
io_init
autoresize
ubi_attach_mtd_dev
ubi_detach_mtd_dev
open_mtd_by_chdev
open_mtd_device
ubi_init
ubi_exit
bytes_str_to_int
ubi_mtd_param_parse
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (c) International Business Machines Corp., 2006
   4  * Copyright (c) Nokia Corporation, 2007
   5  *
   6  * Author: Artem Bityutskiy (Битюцкий Артём),
   7  *         Frank Haverkamp
   8  */
   9 
  10 /*
  11  * This file includes UBI initialization and building of UBI devices.
  12  *
  13  * When UBI is initialized, it attaches all the MTD devices specified as the
  14  * module load parameters or the kernel boot parameters. If MTD devices were
  15  * specified, UBI does not attach any MTD device, but it is possible to do
  16  * later using the "UBI control device".
  17  */
  18 
  19 #include <linux/err.h>
  20 #include <linux/module.h>
  21 #include <linux/moduleparam.h>
  22 #include <linux/stringify.h>
  23 #include <linux/namei.h>
  24 #include <linux/stat.h>
  25 #include <linux/miscdevice.h>
  26 #include <linux/mtd/partitions.h>
  27 #include <linux/log2.h>
  28 #include <linux/kthread.h>
  29 #include <linux/kernel.h>
  30 #include <linux/slab.h>
  31 #include <linux/major.h>
  32 #include "ubi.h"
  33 
  34 /* Maximum length of the 'mtd=' parameter */
  35 #define MTD_PARAM_LEN_MAX 64
  36 
  37 /* Maximum number of comma-separated items in the 'mtd=' parameter */
  38 #define MTD_PARAM_MAX_COUNT 4
  39 
  40 /* Maximum value for the number of bad PEBs per 1024 PEBs */
  41 #define MAX_MTD_UBI_BEB_LIMIT 768
  42 
  43 #ifdef CONFIG_MTD_UBI_MODULE
  44 #define ubi_is_module() 1
  45 #else
  46 #define ubi_is_module() 0
  47 #endif
  48 
  49 /**
  50  * struct mtd_dev_param - MTD device parameter description data structure.
  51  * @name: MTD character device node path, MTD device name, or MTD device number
  52  *        string
  53  * @vid_hdr_offs: VID header offset
  54  * @max_beb_per1024: maximum expected number of bad PEBs per 1024 PEBs
  55  */
  56 struct mtd_dev_param {
  57         char name[MTD_PARAM_LEN_MAX];
  58         int ubi_num;
  59         int vid_hdr_offs;
  60         int max_beb_per1024;
  61 };
  62 
  63 /* Numbers of elements set in the @mtd_dev_param array */
  64 static int mtd_devs;
  65 
  66 /* MTD devices specification parameters */
  67 static struct mtd_dev_param mtd_dev_param[UBI_MAX_DEVICES];
  68 #ifdef CONFIG_MTD_UBI_FASTMAP
  69 /* UBI module parameter to enable fastmap automatically on non-fastmap images */
  70 static bool fm_autoconvert;
  71 static bool fm_debug;
  72 #endif
  73 
  74 /* Slab cache for wear-leveling entries */
  75 struct kmem_cache *ubi_wl_entry_slab;
  76 
  77 /* UBI control character device */
  78 static struct miscdevice ubi_ctrl_cdev = {
  79         .minor = MISC_DYNAMIC_MINOR,
  80         .name = "ubi_ctrl",
  81         .fops = &ubi_ctrl_cdev_operations,
  82 };
  83 
  84 /* All UBI devices in system */
  85 static struct ubi_device *ubi_devices[UBI_MAX_DEVICES];
  86 
  87 /* Serializes UBI devices creations and removals */
  88 DEFINE_MUTEX(ubi_devices_mutex);
  89 
  90 /* Protects @ubi_devices and @ubi->ref_count */
  91 static DEFINE_SPINLOCK(ubi_devices_lock);
  92 
  93 /* "Show" method for files in '/<sysfs>/class/ubi/' */
  94 /* UBI version attribute ('/<sysfs>/class/ubi/version') */
  95 static ssize_t version_show(struct class *class, struct class_attribute *attr,
  96                             char *buf)
  97 {
  98         return sprintf(buf, "%d\n", UBI_VERSION);
  99 }
 100 static CLASS_ATTR_RO(version);
 101 
 102 static struct attribute *ubi_class_attrs[] = {
 103         &class_attr_version.attr,
 104         NULL,
 105 };
 106 ATTRIBUTE_GROUPS(ubi_class);
 107 
 108 /* Root UBI "class" object (corresponds to '/<sysfs>/class/ubi/') */
 109 struct class ubi_class = {
 110         .name           = UBI_NAME_STR,
 111         .owner          = THIS_MODULE,
 112         .class_groups   = ubi_class_groups,
 113 };
 114 
 115 static ssize_t dev_attribute_show(struct device *dev,
 116                                   struct device_attribute *attr, char *buf);
 117 
 118 /* UBI device attributes (correspond to files in '/<sysfs>/class/ubi/ubiX') */
 119 static struct device_attribute dev_eraseblock_size =
 120         __ATTR(eraseblock_size, S_IRUGO, dev_attribute_show, NULL);
 121 static struct device_attribute dev_avail_eraseblocks =
 122         __ATTR(avail_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
 123 static struct device_attribute dev_total_eraseblocks =
 124         __ATTR(total_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
 125 static struct device_attribute dev_volumes_count =
 126         __ATTR(volumes_count, S_IRUGO, dev_attribute_show, NULL);
 127 static struct device_attribute dev_max_ec =
 128         __ATTR(max_ec, S_IRUGO, dev_attribute_show, NULL);
 129 static struct device_attribute dev_reserved_for_bad =
 130         __ATTR(reserved_for_bad, S_IRUGO, dev_attribute_show, NULL);
 131 static struct device_attribute dev_bad_peb_count =
 132         __ATTR(bad_peb_count, S_IRUGO, dev_attribute_show, NULL);
 133 static struct device_attribute dev_max_vol_count =
 134         __ATTR(max_vol_count, S_IRUGO, dev_attribute_show, NULL);
 135 static struct device_attribute dev_min_io_size =
 136         __ATTR(min_io_size, S_IRUGO, dev_attribute_show, NULL);
 137 static struct device_attribute dev_bgt_enabled =
 138         __ATTR(bgt_enabled, S_IRUGO, dev_attribute_show, NULL);
 139 static struct device_attribute dev_mtd_num =
 140         __ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL);
 141 static struct device_attribute dev_ro_mode =
 142         __ATTR(ro_mode, S_IRUGO, dev_attribute_show, NULL);
 143 
 144 /**
 145  * ubi_volume_notify - send a volume change notification.
 146  * @ubi: UBI device description object
 147  * @vol: volume description object of the changed volume
 148  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
 149  *
 150  * This is a helper function which notifies all subscribers about a volume
 151  * change event (creation, removal, re-sizing, re-naming, updating). Returns
 152  * zero in case of success and a negative error code in case of failure.
 153  */
 154 int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol, int ntype)
 155 {
 156         int ret;
 157         struct ubi_notification nt;
 158 
 159         ubi_do_get_device_info(ubi, &nt.di);
 160         ubi_do_get_volume_info(ubi, vol, &nt.vi);
 161 
 162         switch (ntype) {
 163         case UBI_VOLUME_ADDED:
 164         case UBI_VOLUME_REMOVED:
 165         case UBI_VOLUME_RESIZED:
 166         case UBI_VOLUME_RENAMED:
 167                 ret = ubi_update_fastmap(ubi);
 168                 if (ret)
 169                         ubi_msg(ubi, "Unable to write a new fastmap: %i", ret);
 170         }
 171 
 172         return blocking_notifier_call_chain(&ubi_notifiers, ntype, &nt);
 173 }
 174 
 175 /**
 176  * ubi_notify_all - send a notification to all volumes.
 177  * @ubi: UBI device description object
 178  * @ntype: notification type to send (%UBI_VOLUME_ADDED, etc)
 179  * @nb: the notifier to call
 180  *
 181  * This function walks all volumes of UBI device @ubi and sends the @ntype
 182  * notification for each volume. If @nb is %NULL, then all registered notifiers
 183  * are called, otherwise only the @nb notifier is called. Returns the number of
 184  * sent notifications.
 185  */
 186 int ubi_notify_all(struct ubi_device *ubi, int ntype, struct notifier_block *nb)
 187 {
 188         struct ubi_notification nt;
 189         int i, count = 0;
 190 
 191         ubi_do_get_device_info(ubi, &nt.di);
 192 
 193         mutex_lock(&ubi->device_mutex);
 194         for (i = 0; i < ubi->vtbl_slots; i++) {
 195                 /*
 196                  * Since the @ubi->device is locked, and we are not going to
 197                  * change @ubi->volumes, we do not have to lock
 198                  * @ubi->volumes_lock.
 199                  */
 200                 if (!ubi->volumes[i])
 201                         continue;
 202 
 203                 ubi_do_get_volume_info(ubi, ubi->volumes[i], &nt.vi);
 204                 if (nb)
 205                         nb->notifier_call(nb, ntype, &nt);
 206                 else
 207                         blocking_notifier_call_chain(&ubi_notifiers, ntype,
 208                                                      &nt);
 209                 count += 1;
 210         }
 211         mutex_unlock(&ubi->device_mutex);
 212 
 213         return count;
 214 }
 215 
 216 /**
 217  * ubi_enumerate_volumes - send "add" notification for all existing volumes.
 218  * @nb: the notifier to call
 219  *
 220  * This function walks all UBI devices and volumes and sends the
 221  * %UBI_VOLUME_ADDED notification for each volume. If @nb is %NULL, then all
 222  * registered notifiers are called, otherwise only the @nb notifier is called.
 223  * Returns the number of sent notifications.
 224  */
 225 int ubi_enumerate_volumes(struct notifier_block *nb)
 226 {
 227         int i, count = 0;
 228 
 229         /*
 230          * Since the @ubi_devices_mutex is locked, and we are not going to
 231          * change @ubi_devices, we do not have to lock @ubi_devices_lock.
 232          */
 233         for (i = 0; i < UBI_MAX_DEVICES; i++) {
 234                 struct ubi_device *ubi = ubi_devices[i];
 235 
 236                 if (!ubi)
 237                         continue;
 238                 count += ubi_notify_all(ubi, UBI_VOLUME_ADDED, nb);
 239         }
 240 
 241         return count;
 242 }
 243 
 244 /**
 245  * ubi_get_device - get UBI device.
 246  * @ubi_num: UBI device number
 247  *
 248  * This function returns UBI device description object for UBI device number
 249  * @ubi_num, or %NULL if the device does not exist. This function increases the
 250  * device reference count to prevent removal of the device. In other words, the
 251  * device cannot be removed if its reference count is not zero.
 252  */
 253 struct ubi_device *ubi_get_device(int ubi_num)
 254 {
 255         struct ubi_device *ubi;
 256 
 257         spin_lock(&ubi_devices_lock);
 258         ubi = ubi_devices[ubi_num];
 259         if (ubi) {
 260                 ubi_assert(ubi->ref_count >= 0);
 261                 ubi->ref_count += 1;
 262                 get_device(&ubi->dev);
 263         }
 264         spin_unlock(&ubi_devices_lock);
 265 
 266         return ubi;
 267 }
 268 
 269 /**
 270  * ubi_put_device - drop an UBI device reference.
 271  * @ubi: UBI device description object
 272  */
 273 void ubi_put_device(struct ubi_device *ubi)
 274 {
 275         spin_lock(&ubi_devices_lock);
 276         ubi->ref_count -= 1;
 277         put_device(&ubi->dev);
 278         spin_unlock(&ubi_devices_lock);
 279 }
 280 
 281 /**
 282  * ubi_get_by_major - get UBI device by character device major number.
 283  * @major: major number
 284  *
 285  * This function is similar to 'ubi_get_device()', but it searches the device
 286  * by its major number.
 287  */
 288 struct ubi_device *ubi_get_by_major(int major)
 289 {
 290         int i;
 291         struct ubi_device *ubi;
 292 
 293         spin_lock(&ubi_devices_lock);
 294         for (i = 0; i < UBI_MAX_DEVICES; i++) {
 295                 ubi = ubi_devices[i];
 296                 if (ubi && MAJOR(ubi->cdev.dev) == major) {
 297                         ubi_assert(ubi->ref_count >= 0);
 298                         ubi->ref_count += 1;
 299                         get_device(&ubi->dev);
 300                         spin_unlock(&ubi_devices_lock);
 301                         return ubi;
 302                 }
 303         }
 304         spin_unlock(&ubi_devices_lock);
 305 
 306         return NULL;
 307 }
 308 
 309 /**
 310  * ubi_major2num - get UBI device number by character device major number.
 311  * @major: major number
 312  *
 313  * This function searches UBI device number object by its major number. If UBI
 314  * device was not found, this function returns -ENODEV, otherwise the UBI device
 315  * number is returned.
 316  */
 317 int ubi_major2num(int major)
 318 {
 319         int i, ubi_num = -ENODEV;
 320 
 321         spin_lock(&ubi_devices_lock);
 322         for (i = 0; i < UBI_MAX_DEVICES; i++) {
 323                 struct ubi_device *ubi = ubi_devices[i];
 324 
 325                 if (ubi && MAJOR(ubi->cdev.dev) == major) {
 326                         ubi_num = ubi->ubi_num;
 327                         break;
 328                 }
 329         }
 330         spin_unlock(&ubi_devices_lock);
 331 
 332         return ubi_num;
 333 }
 334 
 335 /* "Show" method for files in '/<sysfs>/class/ubi/ubiX/' */
 336 static ssize_t dev_attribute_show(struct device *dev,
 337                                   struct device_attribute *attr, char *buf)
 338 {
 339         ssize_t ret;
 340         struct ubi_device *ubi;
 341 
 342         /*
 343          * The below code looks weird, but it actually makes sense. We get the
 344          * UBI device reference from the contained 'struct ubi_device'. But it
 345          * is unclear if the device was removed or not yet. Indeed, if the
 346          * device was removed before we increased its reference count,
 347          * 'ubi_get_device()' will return -ENODEV and we fail.
 348          *
 349          * Remember, 'struct ubi_device' is freed in the release function, so
 350          * we still can use 'ubi->ubi_num'.
 351          */
 352         ubi = container_of(dev, struct ubi_device, dev);
 353         ubi = ubi_get_device(ubi->ubi_num);
 354         if (!ubi)
 355                 return -ENODEV;
 356 
 357         if (attr == &dev_eraseblock_size)
 358                 ret = sprintf(buf, "%d\n", ubi->leb_size);
 359         else if (attr == &dev_avail_eraseblocks)
 360                 ret = sprintf(buf, "%d\n", ubi->avail_pebs);
 361         else if (attr == &dev_total_eraseblocks)
 362                 ret = sprintf(buf, "%d\n", ubi->good_peb_count);
 363         else if (attr == &dev_volumes_count)
 364                 ret = sprintf(buf, "%d\n", ubi->vol_count - UBI_INT_VOL_COUNT);
 365         else if (attr == &dev_max_ec)
 366                 ret = sprintf(buf, "%d\n", ubi->max_ec);
 367         else if (attr == &dev_reserved_for_bad)
 368                 ret = sprintf(buf, "%d\n", ubi->beb_rsvd_pebs);
 369         else if (attr == &dev_bad_peb_count)
 370                 ret = sprintf(buf, "%d\n", ubi->bad_peb_count);
 371         else if (attr == &dev_max_vol_count)
 372                 ret = sprintf(buf, "%d\n", ubi->vtbl_slots);
 373         else if (attr == &dev_min_io_size)
 374                 ret = sprintf(buf, "%d\n", ubi->min_io_size);
 375         else if (attr == &dev_bgt_enabled)
 376                 ret = sprintf(buf, "%d\n", ubi->thread_enabled);
 377         else if (attr == &dev_mtd_num)
 378                 ret = sprintf(buf, "%d\n", ubi->mtd->index);
 379         else if (attr == &dev_ro_mode)
 380                 ret = sprintf(buf, "%d\n", ubi->ro_mode);
 381         else
 382                 ret = -EINVAL;
 383 
 384         ubi_put_device(ubi);
 385         return ret;
 386 }
 387 
 388 static struct attribute *ubi_dev_attrs[] = {
 389         &dev_eraseblock_size.attr,
 390         &dev_avail_eraseblocks.attr,
 391         &dev_total_eraseblocks.attr,
 392         &dev_volumes_count.attr,
 393         &dev_max_ec.attr,
 394         &dev_reserved_for_bad.attr,
 395         &dev_bad_peb_count.attr,
 396         &dev_max_vol_count.attr,
 397         &dev_min_io_size.attr,
 398         &dev_bgt_enabled.attr,
 399         &dev_mtd_num.attr,
 400         &dev_ro_mode.attr,
 401         NULL
 402 };
 403 ATTRIBUTE_GROUPS(ubi_dev);
 404 
 405 static void dev_release(struct device *dev)
 406 {
 407         struct ubi_device *ubi = container_of(dev, struct ubi_device, dev);
 408 
 409         kfree(ubi);
 410 }
 411 
 412 /**
 413  * kill_volumes - destroy all user volumes.
 414  * @ubi: UBI device description object
 415  */
 416 static void kill_volumes(struct ubi_device *ubi)
 417 {
 418         int i;
 419 
 420         for (i = 0; i < ubi->vtbl_slots; i++)
 421                 if (ubi->volumes[i])
 422                         ubi_free_volume(ubi, ubi->volumes[i]);
 423 }
 424 
 425 /**
 426  * uif_init - initialize user interfaces for an UBI device.
 427  * @ubi: UBI device description object
 428  *
 429  * This function initializes various user interfaces for an UBI device. If the
 430  * initialization fails at an early stage, this function frees all the
 431  * resources it allocated, returns an error.
 432  *
 433  * This function returns zero in case of success and a negative error code in
 434  * case of failure.
 435  */
 436 static int uif_init(struct ubi_device *ubi)
 437 {
 438         int i, err;
 439         dev_t dev;
 440 
 441         sprintf(ubi->ubi_name, UBI_NAME_STR "%d", ubi->ubi_num);
 442 
 443         /*
 444          * Major numbers for the UBI character devices are allocated
 445          * dynamically. Major numbers of volume character devices are
 446          * equivalent to ones of the corresponding UBI character device. Minor
 447          * numbers of UBI character devices are 0, while minor numbers of
 448          * volume character devices start from 1. Thus, we allocate one major
 449          * number and ubi->vtbl_slots + 1 minor numbers.
 450          */
 451         err = alloc_chrdev_region(&dev, 0, ubi->vtbl_slots + 1, ubi->ubi_name);
 452         if (err) {
 453                 ubi_err(ubi, "cannot register UBI character devices");
 454                 return err;
 455         }
 456 
 457         ubi->dev.devt = dev;
 458 
 459         ubi_assert(MINOR(dev) == 0);
 460         cdev_init(&ubi->cdev, &ubi_cdev_operations);
 461         dbg_gen("%s major is %u", ubi->ubi_name, MAJOR(dev));
 462         ubi->cdev.owner = THIS_MODULE;
 463 
 464         dev_set_name(&ubi->dev, UBI_NAME_STR "%d", ubi->ubi_num);
 465         err = cdev_device_add(&ubi->cdev, &ubi->dev);
 466         if (err)
 467                 goto out_unreg;
 468 
 469         for (i = 0; i < ubi->vtbl_slots; i++)
 470                 if (ubi->volumes[i]) {
 471                         err = ubi_add_volume(ubi, ubi->volumes[i]);
 472                         if (err) {
 473                                 ubi_err(ubi, "cannot add volume %d", i);
 474                                 goto out_volumes;
 475                         }
 476                 }
 477 
 478         return 0;
 479 
 480 out_volumes:
 481         kill_volumes(ubi);
 482         cdev_device_del(&ubi->cdev, &ubi->dev);
 483 out_unreg:
 484         unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
 485         ubi_err(ubi, "cannot initialize UBI %s, error %d",
 486                 ubi->ubi_name, err);
 487         return err;
 488 }
 489 
 490 /**
 491  * uif_close - close user interfaces for an UBI device.
 492  * @ubi: UBI device description object
 493  *
 494  * Note, since this function un-registers UBI volume device objects (@vol->dev),
 495  * the memory allocated voe the volumes is freed as well (in the release
 496  * function).
 497  */
 498 static void uif_close(struct ubi_device *ubi)
 499 {
 500         kill_volumes(ubi);
 501         cdev_device_del(&ubi->cdev, &ubi->dev);
 502         unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
 503 }
 504 
 505 /**
 506  * ubi_free_internal_volumes - free internal volumes.
 507  * @ubi: UBI device description object
 508  */
 509 void ubi_free_internal_volumes(struct ubi_device *ubi)
 510 {
 511         int i;
 512 
 513         for (i = ubi->vtbl_slots;
 514              i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
 515                 ubi_eba_replace_table(ubi->volumes[i], NULL);
 516                 ubi_fastmap_destroy_checkmap(ubi->volumes[i]);
 517                 kfree(ubi->volumes[i]);
 518         }
 519 }
 520 
 521 static int get_bad_peb_limit(const struct ubi_device *ubi, int max_beb_per1024)
 522 {
 523         int limit, device_pebs;
 524         uint64_t device_size;
 525 
 526         if (!max_beb_per1024) {
 527                 /*
 528                  * Since max_beb_per1024 has not been set by the user in either
 529                  * the cmdline or Kconfig, use mtd_max_bad_blocks to set the
 530                  * limit if it is supported by the device.
 531                  */
 532                 limit = mtd_max_bad_blocks(ubi->mtd, 0, ubi->mtd->size);
 533                 if (limit < 0)
 534                         return 0;
 535                 return limit;
 536         }
 537 
 538         /*
 539          * Here we are using size of the entire flash chip and
 540          * not just the MTD partition size because the maximum
 541          * number of bad eraseblocks is a percentage of the
 542          * whole device and bad eraseblocks are not fairly
 543          * distributed over the flash chip. So the worst case
 544          * is that all the bad eraseblocks of the chip are in
 545          * the MTD partition we are attaching (ubi->mtd).
 546          */
 547         device_size = mtd_get_device_size(ubi->mtd);
 548         device_pebs = mtd_div_by_eb(device_size, ubi->mtd);
 549         limit = mult_frac(device_pebs, max_beb_per1024, 1024);
 550 
 551         /* Round it up */
 552         if (mult_frac(limit, 1024, max_beb_per1024) < device_pebs)
 553                 limit += 1;
 554 
 555         return limit;
 556 }
 557 
 558 /**
 559  * io_init - initialize I/O sub-system for a given UBI device.
 560  * @ubi: UBI device description object
 561  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
 562  *
 563  * If @ubi->vid_hdr_offset or @ubi->leb_start is zero, default offsets are
 564  * assumed:
 565  *   o EC header is always at offset zero - this cannot be changed;
 566  *   o VID header starts just after the EC header at the closest address
 567  *     aligned to @io->hdrs_min_io_size;
 568  *   o data starts just after the VID header at the closest address aligned to
 569  *     @io->min_io_size
 570  *
 571  * This function returns zero in case of success and a negative error code in
 572  * case of failure.
 573  */
 574 static int io_init(struct ubi_device *ubi, int max_beb_per1024)
 575 {
 576         dbg_gen("sizeof(struct ubi_ainf_peb) %zu", sizeof(struct ubi_ainf_peb));
 577         dbg_gen("sizeof(struct ubi_wl_entry) %zu", sizeof(struct ubi_wl_entry));
 578 
 579         if (ubi->mtd->numeraseregions != 0) {
 580                 /*
 581                  * Some flashes have several erase regions. Different regions
 582                  * may have different eraseblock size and other
 583                  * characteristics. It looks like mostly multi-region flashes
 584                  * have one "main" region and one or more small regions to
 585                  * store boot loader code or boot parameters or whatever. I
 586                  * guess we should just pick the largest region. But this is
 587                  * not implemented.
 588                  */
 589                 ubi_err(ubi, "multiple regions, not implemented");
 590                 return -EINVAL;
 591         }
 592 
 593         if (ubi->vid_hdr_offset < 0)
 594                 return -EINVAL;
 595 
 596         /*
 597          * Note, in this implementation we support MTD devices with 0x7FFFFFFF
 598          * physical eraseblocks maximum.
 599          */
 600 
 601         ubi->peb_size   = ubi->mtd->erasesize;
 602         ubi->peb_count  = mtd_div_by_eb(ubi->mtd->size, ubi->mtd);
 603         ubi->flash_size = ubi->mtd->size;
 604 
 605         if (mtd_can_have_bb(ubi->mtd)) {
 606                 ubi->bad_allowed = 1;
 607                 ubi->bad_peb_limit = get_bad_peb_limit(ubi, max_beb_per1024);
 608         }
 609 
 610         if (ubi->mtd->type == MTD_NORFLASH) {
 611                 ubi_assert(ubi->mtd->writesize == 1);
 612                 ubi->nor_flash = 1;
 613         }
 614 
 615         ubi->min_io_size = ubi->mtd->writesize;
 616         ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;
 617 
 618         /*
 619          * Make sure minimal I/O unit is power of 2. Note, there is no
 620          * fundamental reason for this assumption. It is just an optimization
 621          * which allows us to avoid costly division operations.
 622          */
 623         if (!is_power_of_2(ubi->min_io_size)) {
 624                 ubi_err(ubi, "min. I/O unit (%d) is not power of 2",
 625                         ubi->min_io_size);
 626                 return -EINVAL;
 627         }
 628 
 629         ubi_assert(ubi->hdrs_min_io_size > 0);
 630         ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);
 631         ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0);
 632 
 633         ubi->max_write_size = ubi->mtd->writebufsize;
 634         /*
 635          * Maximum write size has to be greater or equivalent to min. I/O
 636          * size, and be multiple of min. I/O size.
 637          */
 638         if (ubi->max_write_size < ubi->min_io_size ||
 639             ubi->max_write_size % ubi->min_io_size ||
 640             !is_power_of_2(ubi->max_write_size)) {
 641                 ubi_err(ubi, "bad write buffer size %d for %d min. I/O unit",
 642                         ubi->max_write_size, ubi->min_io_size);
 643                 return -EINVAL;
 644         }
 645 
 646         /* Calculate default aligned sizes of EC and VID headers */
 647         ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
 648         ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);
 649 
 650         dbg_gen("min_io_size      %d", ubi->min_io_size);
 651         dbg_gen("max_write_size   %d", ubi->max_write_size);
 652         dbg_gen("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
 653         dbg_gen("ec_hdr_alsize    %d", ubi->ec_hdr_alsize);
 654         dbg_gen("vid_hdr_alsize   %d", ubi->vid_hdr_alsize);
 655 
 656         if (ubi->vid_hdr_offset == 0)
 657                 /* Default offset */
 658                 ubi->vid_hdr_offset = ubi->vid_hdr_aloffset =
 659                                       ubi->ec_hdr_alsize;
 660         else {
 661                 ubi->vid_hdr_aloffset = ubi->vid_hdr_offset &
 662                                                 ~(ubi->hdrs_min_io_size - 1);
 663                 ubi->vid_hdr_shift = ubi->vid_hdr_offset -
 664                                                 ubi->vid_hdr_aloffset;
 665         }
 666 
 667         /* Similar for the data offset */
 668         ubi->leb_start = ubi->vid_hdr_offset + UBI_VID_HDR_SIZE;
 669         ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);
 670 
 671         dbg_gen("vid_hdr_offset   %d", ubi->vid_hdr_offset);
 672         dbg_gen("vid_hdr_aloffset %d", ubi->vid_hdr_aloffset);
 673         dbg_gen("vid_hdr_shift    %d", ubi->vid_hdr_shift);
 674         dbg_gen("leb_start        %d", ubi->leb_start);
 675 
 676         /* The shift must be aligned to 32-bit boundary */
 677         if (ubi->vid_hdr_shift % 4) {
 678                 ubi_err(ubi, "unaligned VID header shift %d",
 679                         ubi->vid_hdr_shift);
 680                 return -EINVAL;
 681         }
 682 
 683         /* Check sanity */
 684         if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||
 685             ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||
 686             ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||
 687             ubi->leb_start & (ubi->min_io_size - 1)) {
 688                 ubi_err(ubi, "bad VID header (%d) or data offsets (%d)",
 689                         ubi->vid_hdr_offset, ubi->leb_start);
 690                 return -EINVAL;
 691         }
 692 
 693         /*
 694          * Set maximum amount of physical erroneous eraseblocks to be 10%.
 695          * Erroneous PEB are those which have read errors.
 696          */
 697         ubi->max_erroneous = ubi->peb_count / 10;
 698         if (ubi->max_erroneous < 16)
 699                 ubi->max_erroneous = 16;
 700         dbg_gen("max_erroneous    %d", ubi->max_erroneous);
 701 
 702         /*
 703          * It may happen that EC and VID headers are situated in one minimal
 704          * I/O unit. In this case we can only accept this UBI image in
 705          * read-only mode.
 706          */
 707         if (ubi->vid_hdr_offset + UBI_VID_HDR_SIZE <= ubi->hdrs_min_io_size) {
 708                 ubi_warn(ubi, "EC and VID headers are in the same minimal I/O unit, switch to read-only mode");
 709                 ubi->ro_mode = 1;
 710         }
 711 
 712         ubi->leb_size = ubi->peb_size - ubi->leb_start;
 713 
 714         if (!(ubi->mtd->flags & MTD_WRITEABLE)) {
 715                 ubi_msg(ubi, "MTD device %d is write-protected, attach in read-only mode",
 716                         ubi->mtd->index);
 717                 ubi->ro_mode = 1;
 718         }
 719 
 720         /*
 721          * Note, ideally, we have to initialize @ubi->bad_peb_count here. But
 722          * unfortunately, MTD does not provide this information. We should loop
 723          * over all physical eraseblocks and invoke mtd->block_is_bad() for
 724          * each physical eraseblock. So, we leave @ubi->bad_peb_count
 725          * uninitialized so far.
 726          */
 727 
 728         return 0;
 729 }
 730 
 731 /**
 732  * autoresize - re-size the volume which has the "auto-resize" flag set.
 733  * @ubi: UBI device description object
 734  * @vol_id: ID of the volume to re-size
 735  *
 736  * This function re-sizes the volume marked by the %UBI_VTBL_AUTORESIZE_FLG in
 737  * the volume table to the largest possible size. See comments in ubi-header.h
 738  * for more description of the flag. Returns zero in case of success and a
 739  * negative error code in case of failure.
 740  */
 741 static int autoresize(struct ubi_device *ubi, int vol_id)
 742 {
 743         struct ubi_volume_desc desc;
 744         struct ubi_volume *vol = ubi->volumes[vol_id];
 745         int err, old_reserved_pebs = vol->reserved_pebs;
 746 
 747         if (ubi->ro_mode) {
 748                 ubi_warn(ubi, "skip auto-resize because of R/O mode");
 749                 return 0;
 750         }
 751 
 752         /*
 753          * Clear the auto-resize flag in the volume in-memory copy of the
 754          * volume table, and 'ubi_resize_volume()' will propagate this change
 755          * to the flash.
 756          */
 757         ubi->vtbl[vol_id].flags &= ~UBI_VTBL_AUTORESIZE_FLG;
 758 
 759         if (ubi->avail_pebs == 0) {
 760                 struct ubi_vtbl_record vtbl_rec;
 761 
 762                 /*
 763                  * No available PEBs to re-size the volume, clear the flag on
 764                  * flash and exit.
 765                  */
 766                 vtbl_rec = ubi->vtbl[vol_id];
 767                 err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
 768                 if (err)
 769                         ubi_err(ubi, "cannot clean auto-resize flag for volume %d",
 770                                 vol_id);
 771         } else {
 772                 desc.vol = vol;
 773                 err = ubi_resize_volume(&desc,
 774                                         old_reserved_pebs + ubi->avail_pebs);
 775                 if (err)
 776                         ubi_err(ubi, "cannot auto-resize volume %d",
 777                                 vol_id);
 778         }
 779 
 780         if (err)
 781                 return err;
 782 
 783         ubi_msg(ubi, "volume %d (\"%s\") re-sized from %d to %d LEBs",
 784                 vol_id, vol->name, old_reserved_pebs, vol->reserved_pebs);
 785         return 0;
 786 }
 787 
 788 /**
 789  * ubi_attach_mtd_dev - attach an MTD device.
 790  * @mtd: MTD device description object
 791  * @ubi_num: number to assign to the new UBI device
 792  * @vid_hdr_offset: VID header offset
 793  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
 794  *
 795  * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number
 796  * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in
 797  * which case this function finds a vacant device number and assigns it
 798  * automatically. Returns the new UBI device number in case of success and a
 799  * negative error code in case of failure.
 800  *
 801  * Note, the invocations of this function has to be serialized by the
 802  * @ubi_devices_mutex.
 803  */
 804 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
 805                        int vid_hdr_offset, int max_beb_per1024)
 806 {
 807         struct ubi_device *ubi;
 808         int i, err;
 809 
 810         if (max_beb_per1024 < 0 || max_beb_per1024 > MAX_MTD_UBI_BEB_LIMIT)
 811                 return -EINVAL;
 812 
 813         if (!max_beb_per1024)
 814                 max_beb_per1024 = CONFIG_MTD_UBI_BEB_LIMIT;
 815 
 816         /*
 817          * Check if we already have the same MTD device attached.
 818          *
 819          * Note, this function assumes that UBI devices creations and deletions
 820          * are serialized, so it does not take the &ubi_devices_lock.
 821          */
 822         for (i = 0; i < UBI_MAX_DEVICES; i++) {
 823                 ubi = ubi_devices[i];
 824                 if (ubi && mtd->index == ubi->mtd->index) {
 825                         pr_err("ubi: mtd%d is already attached to ubi%d\n",
 826                                 mtd->index, i);
 827                         return -EEXIST;
 828                 }
 829         }
 830 
 831         /*
 832          * Make sure this MTD device is not emulated on top of an UBI volume
 833          * already. Well, generally this recursion works fine, but there are
 834          * different problems like the UBI module takes a reference to itself
 835          * by attaching (and thus, opening) the emulated MTD device. This
 836          * results in inability to unload the module. And in general it makes
 837          * no sense to attach emulated MTD devices, so we prohibit this.
 838          */
 839         if (mtd->type == MTD_UBIVOLUME) {
 840                 pr_err("ubi: refuse attaching mtd%d - it is already emulated on top of UBI\n",
 841                         mtd->index);
 842                 return -EINVAL;
 843         }
 844 
 845         /*
 846          * Both UBI and UBIFS have been designed for SLC NAND and NOR flashes.
 847          * MLC NAND is different and needs special care, otherwise UBI or UBIFS
 848          * will die soon and you will lose all your data.
 849          */
 850         if (mtd->type == MTD_MLCNANDFLASH) {
 851                 pr_err("ubi: refuse attaching mtd%d - MLC NAND is not supported\n",
 852                         mtd->index);
 853                 return -EINVAL;
 854         }
 855 
 856         if (ubi_num == UBI_DEV_NUM_AUTO) {
 857                 /* Search for an empty slot in the @ubi_devices array */
 858                 for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)
 859                         if (!ubi_devices[ubi_num])
 860                                 break;
 861                 if (ubi_num == UBI_MAX_DEVICES) {
 862                         pr_err("ubi: only %d UBI devices may be created\n",
 863                                 UBI_MAX_DEVICES);
 864                         return -ENFILE;
 865                 }
 866         } else {
 867                 if (ubi_num >= UBI_MAX_DEVICES)
 868                         return -EINVAL;
 869 
 870                 /* Make sure ubi_num is not busy */
 871                 if (ubi_devices[ubi_num]) {
 872                         pr_err("ubi: ubi%i already exists\n", ubi_num);
 873                         return -EEXIST;
 874                 }
 875         }
 876 
 877         ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL);
 878         if (!ubi)
 879                 return -ENOMEM;
 880 
 881         device_initialize(&ubi->dev);
 882         ubi->dev.release = dev_release;
 883         ubi->dev.class = &ubi_class;
 884         ubi->dev.groups = ubi_dev_groups;
 885 
 886         ubi->mtd = mtd;
 887         ubi->ubi_num = ubi_num;
 888         ubi->vid_hdr_offset = vid_hdr_offset;
 889         ubi->autoresize_vol_id = -1;
 890 
 891 #ifdef CONFIG_MTD_UBI_FASTMAP
 892         ubi->fm_pool.used = ubi->fm_pool.size = 0;
 893         ubi->fm_wl_pool.used = ubi->fm_wl_pool.size = 0;
 894 
 895         /*
 896          * fm_pool.max_size is 5% of the total number of PEBs but it's also
 897          * between UBI_FM_MAX_POOL_SIZE and UBI_FM_MIN_POOL_SIZE.
 898          */
 899         ubi->fm_pool.max_size = min(((int)mtd_div_by_eb(ubi->mtd->size,
 900                 ubi->mtd) / 100) * 5, UBI_FM_MAX_POOL_SIZE);
 901         ubi->fm_pool.max_size = max(ubi->fm_pool.max_size,
 902                 UBI_FM_MIN_POOL_SIZE);
 903 
 904         ubi->fm_wl_pool.max_size = ubi->fm_pool.max_size / 2;
 905         ubi->fm_disabled = !fm_autoconvert;
 906         if (fm_debug)
 907                 ubi_enable_dbg_chk_fastmap(ubi);
 908 
 909         if (!ubi->fm_disabled && (int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd)
 910             <= UBI_FM_MAX_START) {
 911                 ubi_err(ubi, "More than %i PEBs are needed for fastmap, sorry.",
 912                         UBI_FM_MAX_START);
 913                 ubi->fm_disabled = 1;
 914         }
 915 
 916         ubi_msg(ubi, "default fastmap pool size: %d", ubi->fm_pool.max_size);
 917         ubi_msg(ubi, "default fastmap WL pool size: %d",
 918                 ubi->fm_wl_pool.max_size);
 919 #else
 920         ubi->fm_disabled = 1;
 921 #endif
 922         mutex_init(&ubi->buf_mutex);
 923         mutex_init(&ubi->ckvol_mutex);
 924         mutex_init(&ubi->device_mutex);
 925         spin_lock_init(&ubi->volumes_lock);
 926         init_rwsem(&ubi->fm_protect);
 927         init_rwsem(&ubi->fm_eba_sem);
 928 
 929         ubi_msg(ubi, "attaching mtd%d", mtd->index);
 930 
 931         err = io_init(ubi, max_beb_per1024);
 932         if (err)
 933                 goto out_free;
 934 
 935         err = -ENOMEM;
 936         ubi->peb_buf = vmalloc(ubi->peb_size);
 937         if (!ubi->peb_buf)
 938                 goto out_free;
 939 
 940 #ifdef CONFIG_MTD_UBI_FASTMAP
 941         ubi->fm_size = ubi_calc_fm_size(ubi);
 942         ubi->fm_buf = vzalloc(ubi->fm_size);
 943         if (!ubi->fm_buf)
 944                 goto out_free;
 945 #endif
 946         err = ubi_attach(ubi, 0);
 947         if (err) {
 948                 ubi_err(ubi, "failed to attach mtd%d, error %d",
 949                         mtd->index, err);
 950                 goto out_free;
 951         }
 952 
 953         if (ubi->autoresize_vol_id != -1) {
 954                 err = autoresize(ubi, ubi->autoresize_vol_id);
 955                 if (err)
 956                         goto out_detach;
 957         }
 958 
 959         /* Make device "available" before it becomes accessible via sysfs */
 960         ubi_devices[ubi_num] = ubi;
 961 
 962         err = uif_init(ubi);
 963         if (err)
 964                 goto out_detach;
 965 
 966         err = ubi_debugfs_init_dev(ubi);
 967         if (err)
 968                 goto out_uif;
 969 
 970         ubi->bgt_thread = kthread_create(ubi_thread, ubi, "%s", ubi->bgt_name);
 971         if (IS_ERR(ubi->bgt_thread)) {
 972                 err = PTR_ERR(ubi->bgt_thread);
 973                 ubi_err(ubi, "cannot spawn \"%s\", error %d",
 974                         ubi->bgt_name, err);
 975                 goto out_debugfs;
 976         }
 977 
 978         ubi_msg(ubi, "attached mtd%d (name \"%s\", size %llu MiB)",
 979                 mtd->index, mtd->name, ubi->flash_size >> 20);
 980         ubi_msg(ubi, "PEB size: %d bytes (%d KiB), LEB size: %d bytes",
 981                 ubi->peb_size, ubi->peb_size >> 10, ubi->leb_size);
 982         ubi_msg(ubi, "min./max. I/O unit sizes: %d/%d, sub-page size %d",
 983                 ubi->min_io_size, ubi->max_write_size, ubi->hdrs_min_io_size);
 984         ubi_msg(ubi, "VID header offset: %d (aligned %d), data offset: %d",
 985                 ubi->vid_hdr_offset, ubi->vid_hdr_aloffset, ubi->leb_start);
 986         ubi_msg(ubi, "good PEBs: %d, bad PEBs: %d, corrupted PEBs: %d",
 987                 ubi->good_peb_count, ubi->bad_peb_count, ubi->corr_peb_count);
 988         ubi_msg(ubi, "user volume: %d, internal volumes: %d, max. volumes count: %d",
 989                 ubi->vol_count - UBI_INT_VOL_COUNT, UBI_INT_VOL_COUNT,
 990                 ubi->vtbl_slots);
 991         ubi_msg(ubi, "max/mean erase counter: %d/%d, WL threshold: %d, image sequence number: %u",
 992                 ubi->max_ec, ubi->mean_ec, CONFIG_MTD_UBI_WL_THRESHOLD,
 993                 ubi->image_seq);
 994         ubi_msg(ubi, "available PEBs: %d, total reserved PEBs: %d, PEBs reserved for bad PEB handling: %d",
 995                 ubi->avail_pebs, ubi->rsvd_pebs, ubi->beb_rsvd_pebs);
 996 
 997         /*
 998          * The below lock makes sure we do not race with 'ubi_thread()' which
 999          * checks @ubi->thread_enabled. Otherwise we may fail to wake it up.
1000          */
1001         spin_lock(&ubi->wl_lock);
1002         ubi->thread_enabled = 1;
1003         wake_up_process(ubi->bgt_thread);
1004         spin_unlock(&ubi->wl_lock);
1005 
1006         ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
1007         return ubi_num;
1008 
1009 out_debugfs:
1010         ubi_debugfs_exit_dev(ubi);
1011 out_uif:
1012         uif_close(ubi);
1013 out_detach:
1014         ubi_devices[ubi_num] = NULL;
1015         ubi_wl_close(ubi);
1016         ubi_free_internal_volumes(ubi);
1017         vfree(ubi->vtbl);
1018 out_free:
1019         vfree(ubi->peb_buf);
1020         vfree(ubi->fm_buf);
1021         put_device(&ubi->dev);
1022         return err;
1023 }
1024 
1025 /**
1026  * ubi_detach_mtd_dev - detach an MTD device.
1027  * @ubi_num: UBI device number to detach from
1028  * @anyway: detach MTD even if device reference count is not zero
1029  *
1030  * This function destroys an UBI device number @ubi_num and detaches the
1031  * underlying MTD device. Returns zero in case of success and %-EBUSY if the
1032  * UBI device is busy and cannot be destroyed, and %-EINVAL if it does not
1033  * exist.
1034  *
1035  * Note, the invocations of this function has to be serialized by the
1036  * @ubi_devices_mutex.
1037  */
1038 int ubi_detach_mtd_dev(int ubi_num, int anyway)
1039 {
1040         struct ubi_device *ubi;
1041 
1042         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
1043                 return -EINVAL;
1044 
1045         ubi = ubi_get_device(ubi_num);
1046         if (!ubi)
1047                 return -EINVAL;
1048 
1049         spin_lock(&ubi_devices_lock);
1050         put_device(&ubi->dev);
1051         ubi->ref_count -= 1;
1052         if (ubi->ref_count) {
1053                 if (!anyway) {
1054                         spin_unlock(&ubi_devices_lock);
1055                         return -EBUSY;
1056                 }
1057                 /* This may only happen if there is a bug */
1058                 ubi_err(ubi, "%s reference count %d, destroy anyway",
1059                         ubi->ubi_name, ubi->ref_count);
1060         }
1061         ubi_devices[ubi_num] = NULL;
1062         spin_unlock(&ubi_devices_lock);
1063 
1064         ubi_assert(ubi_num == ubi->ubi_num);
1065         ubi_notify_all(ubi, UBI_VOLUME_REMOVED, NULL);
1066         ubi_msg(ubi, "detaching mtd%d", ubi->mtd->index);
1067 #ifdef CONFIG_MTD_UBI_FASTMAP
1068         /* If we don't write a new fastmap at detach time we lose all
1069          * EC updates that have been made since the last written fastmap.
1070          * In case of fastmap debugging we omit the update to simulate an
1071          * unclean shutdown. */
1072         if (!ubi_dbg_chk_fastmap(ubi))
1073                 ubi_update_fastmap(ubi);
1074 #endif
1075         /*
1076          * Before freeing anything, we have to stop the background thread to
1077          * prevent it from doing anything on this device while we are freeing.
1078          */
1079         if (ubi->bgt_thread)
1080                 kthread_stop(ubi->bgt_thread);
1081 
1082 #ifdef CONFIG_MTD_UBI_FASTMAP
1083         cancel_work_sync(&ubi->fm_work);
1084 #endif
1085         ubi_debugfs_exit_dev(ubi);
1086         uif_close(ubi);
1087 
1088         ubi_wl_close(ubi);
1089         ubi_free_internal_volumes(ubi);
1090         vfree(ubi->vtbl);
1091         vfree(ubi->peb_buf);
1092         vfree(ubi->fm_buf);
1093         ubi_msg(ubi, "mtd%d is detached", ubi->mtd->index);
1094         put_mtd_device(ubi->mtd);
1095         put_device(&ubi->dev);
1096         return 0;
1097 }
1098 
1099 /**
1100  * open_mtd_by_chdev - open an MTD device by its character device node path.
1101  * @mtd_dev: MTD character device node path
1102  *
1103  * This helper function opens an MTD device by its character node device path.
1104  * Returns MTD device description object in case of success and a negative
1105  * error code in case of failure.
1106  */
1107 static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev)
1108 {
1109         int err, minor;
1110         struct path path;
1111         struct kstat stat;
1112 
1113         /* Probably this is an MTD character device node path */
1114         err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path);
1115         if (err)
1116                 return ERR_PTR(err);
1117 
1118         err = vfs_getattr(&path, &stat, STATX_TYPE, AT_STATX_SYNC_AS_STAT);
1119         path_put(&path);
1120         if (err)
1121                 return ERR_PTR(err);
1122 
1123         /* MTD device number is defined by the major / minor numbers */
1124         if (MAJOR(stat.rdev) != MTD_CHAR_MAJOR || !S_ISCHR(stat.mode))
1125                 return ERR_PTR(-EINVAL);
1126 
1127         minor = MINOR(stat.rdev);
1128 
1129         if (minor & 1)
1130                 /*
1131                  * Just do not think the "/dev/mtdrX" devices support is need,
1132                  * so do not support them to avoid doing extra work.
1133                  */
1134                 return ERR_PTR(-EINVAL);
1135 
1136         return get_mtd_device(NULL, minor / 2);
1137 }
1138 
1139 /**
1140  * open_mtd_device - open MTD device by name, character device path, or number.
1141  * @mtd_dev: name, character device node path, or MTD device device number
1142  *
1143  * This function tries to open and MTD device described by @mtd_dev string,
1144  * which is first treated as ASCII MTD device number, and if it is not true, it
1145  * is treated as MTD device name, and if that is also not true, it is treated
1146  * as MTD character device node path. Returns MTD device description object in
1147  * case of success and a negative error code in case of failure.
1148  */
1149 static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
1150 {
1151         struct mtd_info *mtd;
1152         int mtd_num;
1153         char *endp;
1154 
1155         mtd_num = simple_strtoul(mtd_dev, &endp, 0);
1156         if (*endp != '\0' || mtd_dev == endp) {
1157                 /*
1158                  * This does not look like an ASCII integer, probably this is
1159                  * MTD device name.
1160                  */
1161                 mtd = get_mtd_device_nm(mtd_dev);
1162                 if (IS_ERR(mtd) && PTR_ERR(mtd) == -ENODEV)
1163                         /* Probably this is an MTD character device node path */
1164                         mtd = open_mtd_by_chdev(mtd_dev);
1165         } else
1166                 mtd = get_mtd_device(NULL, mtd_num);
1167 
1168         return mtd;
1169 }
1170 
1171 static int __init ubi_init(void)
1172 {
1173         int err, i, k;
1174 
1175         /* Ensure that EC and VID headers have correct size */
1176         BUILD_BUG_ON(sizeof(struct ubi_ec_hdr) != 64);
1177         BUILD_BUG_ON(sizeof(struct ubi_vid_hdr) != 64);
1178 
1179         if (mtd_devs > UBI_MAX_DEVICES) {
1180                 pr_err("UBI error: too many MTD devices, maximum is %d\n",
1181                        UBI_MAX_DEVICES);
1182                 return -EINVAL;
1183         }
1184 
1185         /* Create base sysfs directory and sysfs files */
1186         err = class_register(&ubi_class);
1187         if (err < 0)
1188                 return err;
1189 
1190         err = misc_register(&ubi_ctrl_cdev);
1191         if (err) {
1192                 pr_err("UBI error: cannot register device\n");
1193                 goto out;
1194         }
1195 
1196         ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab",
1197                                               sizeof(struct ubi_wl_entry),
1198                                               0, 0, NULL);
1199         if (!ubi_wl_entry_slab) {
1200                 err = -ENOMEM;
1201                 goto out_dev_unreg;
1202         }
1203 
1204         err = ubi_debugfs_init();
1205         if (err)
1206                 goto out_slab;
1207 
1208 
1209         /* Attach MTD devices */
1210         for (i = 0; i < mtd_devs; i++) {
1211                 struct mtd_dev_param *p = &mtd_dev_param[i];
1212                 struct mtd_info *mtd;
1213 
1214                 cond_resched();
1215 
1216                 mtd = open_mtd_device(p->name);
1217                 if (IS_ERR(mtd)) {
1218                         err = PTR_ERR(mtd);
1219                         pr_err("UBI error: cannot open mtd %s, error %d\n",
1220                                p->name, err);
1221                         /* See comment below re-ubi_is_module(). */
1222                         if (ubi_is_module())
1223                                 goto out_detach;
1224                         continue;
1225                 }
1226 
1227                 mutex_lock(&ubi_devices_mutex);
1228                 err = ubi_attach_mtd_dev(mtd, p->ubi_num,
1229                                          p->vid_hdr_offs, p->max_beb_per1024);
1230                 mutex_unlock(&ubi_devices_mutex);
1231                 if (err < 0) {
1232                         pr_err("UBI error: cannot attach mtd%d\n",
1233                                mtd->index);
1234                         put_mtd_device(mtd);
1235 
1236                         /*
1237                          * Originally UBI stopped initializing on any error.
1238                          * However, later on it was found out that this
1239                          * behavior is not very good when UBI is compiled into
1240                          * the kernel and the MTD devices to attach are passed
1241                          * through the command line. Indeed, UBI failure
1242                          * stopped whole boot sequence.
1243                          *
1244                          * To fix this, we changed the behavior for the
1245                          * non-module case, but preserved the old behavior for
1246                          * the module case, just for compatibility. This is a
1247                          * little inconsistent, though.
1248                          */
1249                         if (ubi_is_module())
1250                                 goto out_detach;
1251                 }
1252         }
1253 
1254         err = ubiblock_init();
1255         if (err) {
1256                 pr_err("UBI error: block: cannot initialize, error %d\n", err);
1257 
1258                 /* See comment above re-ubi_is_module(). */
1259                 if (ubi_is_module())
1260                         goto out_detach;
1261         }
1262 
1263         return 0;
1264 
1265 out_detach:
1266         for (k = 0; k < i; k++)
1267                 if (ubi_devices[k]) {
1268                         mutex_lock(&ubi_devices_mutex);
1269                         ubi_detach_mtd_dev(ubi_devices[k]->ubi_num, 1);
1270                         mutex_unlock(&ubi_devices_mutex);
1271                 }
1272         ubi_debugfs_exit();
1273 out_slab:
1274         kmem_cache_destroy(ubi_wl_entry_slab);
1275 out_dev_unreg:
1276         misc_deregister(&ubi_ctrl_cdev);
1277 out:
1278         class_unregister(&ubi_class);
1279         pr_err("UBI error: cannot initialize UBI, error %d\n", err);
1280         return err;
1281 }
1282 late_initcall(ubi_init);
1283 
1284 static void __exit ubi_exit(void)
1285 {
1286         int i;
1287 
1288         ubiblock_exit();
1289 
1290         for (i = 0; i < UBI_MAX_DEVICES; i++)
1291                 if (ubi_devices[i]) {
1292                         mutex_lock(&ubi_devices_mutex);
1293                         ubi_detach_mtd_dev(ubi_devices[i]->ubi_num, 1);
1294                         mutex_unlock(&ubi_devices_mutex);
1295                 }
1296         ubi_debugfs_exit();
1297         kmem_cache_destroy(ubi_wl_entry_slab);
1298         misc_deregister(&ubi_ctrl_cdev);
1299         class_unregister(&ubi_class);
1300 }
1301 module_exit(ubi_exit);
1302 
1303 /**
1304  * bytes_str_to_int - convert a number of bytes string into an integer.
1305  * @str: the string to convert
1306  *
1307  * This function returns positive resulting integer in case of success and a
1308  * negative error code in case of failure.
1309  */
1310 static int bytes_str_to_int(const char *str)
1311 {
1312         char *endp;
1313         unsigned long result;
1314 
1315         result = simple_strtoul(str, &endp, 0);
1316         if (str == endp || result >= INT_MAX) {
1317                 pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1318                 return -EINVAL;
1319         }
1320 
1321         switch (*endp) {
1322         case 'G':
1323                 result *= 1024;
1324                 /* fall through */
1325         case 'M':
1326                 result *= 1024;
1327                 /* fall through */
1328         case 'K':
1329                 result *= 1024;
1330                 if (endp[1] == 'i' && endp[2] == 'B')
1331                         endp += 2;
1332         case '\0':
1333                 break;
1334         default:
1335                 pr_err("UBI error: incorrect bytes count: \"%s\"\n", str);
1336                 return -EINVAL;
1337         }
1338 
1339         return result;
1340 }
1341 
1342 /**
1343  * ubi_mtd_param_parse - parse the 'mtd=' UBI parameter.
1344  * @val: the parameter value to parse
1345  * @kp: not used
1346  *
1347  * This function returns zero in case of success and a negative error code in
1348  * case of error.
1349  */
1350 static int ubi_mtd_param_parse(const char *val, const struct kernel_param *kp)
1351 {
1352         int i, len;
1353         struct mtd_dev_param *p;
1354         char buf[MTD_PARAM_LEN_MAX];
1355         char *pbuf = &buf[0];
1356         char *tokens[MTD_PARAM_MAX_COUNT], *token;
1357 
1358         if (!val)
1359                 return -EINVAL;
1360 
1361         if (mtd_devs == UBI_MAX_DEVICES) {
1362                 pr_err("UBI error: too many parameters, max. is %d\n",
1363                        UBI_MAX_DEVICES);
1364                 return -EINVAL;
1365         }
1366 
1367         len = strnlen(val, MTD_PARAM_LEN_MAX);
1368         if (len == MTD_PARAM_LEN_MAX) {
1369                 pr_err("UBI error: parameter \"%s\" is too long, max. is %d\n",
1370                        val, MTD_PARAM_LEN_MAX);
1371                 return -EINVAL;
1372         }
1373 
1374         if (len == 0) {
1375                 pr_warn("UBI warning: empty 'mtd=' parameter - ignored\n");
1376                 return 0;
1377         }
1378 
1379         strcpy(buf, val);
1380 
1381         /* Get rid of the final newline */
1382         if (buf[len - 1] == '\n')
1383                 buf[len - 1] = '\0';
1384 
1385         for (i = 0; i < MTD_PARAM_MAX_COUNT; i++)
1386                 tokens[i] = strsep(&pbuf, ",");
1387 
1388         if (pbuf) {
1389                 pr_err("UBI error: too many arguments at \"%s\"\n", val);
1390                 return -EINVAL;
1391         }
1392 
1393         p = &mtd_dev_param[mtd_devs];
1394         strcpy(&p->name[0], tokens[0]);
1395 
1396         token = tokens[1];
1397         if (token) {
1398                 p->vid_hdr_offs = bytes_str_to_int(token);
1399 
1400                 if (p->vid_hdr_offs < 0)
1401                         return p->vid_hdr_offs;
1402         }
1403 
1404         token = tokens[2];
1405         if (token) {
1406                 int err = kstrtoint(token, 10, &p->max_beb_per1024);
1407 
1408                 if (err) {
1409                         pr_err("UBI error: bad value for max_beb_per1024 parameter: %s",
1410                                token);
1411                         return -EINVAL;
1412                 }
1413         }
1414 
1415         token = tokens[3];
1416         if (token) {
1417                 int err = kstrtoint(token, 10, &p->ubi_num);
1418 
1419                 if (err) {
1420                         pr_err("UBI error: bad value for ubi_num parameter: %s",
1421                                token);
1422                         return -EINVAL;
1423                 }
1424         } else
1425                 p->ubi_num = UBI_DEV_NUM_AUTO;
1426 
1427         mtd_devs += 1;
1428         return 0;
1429 }
1430 
1431 module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 0400);
1432 MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: mtd=<name|num|path>[,<vid_hdr_offs>[,max_beb_per1024[,ubi_num]]].\n"
1433                       "Multiple \"mtd\" parameters may be specified.\n"
1434                       "MTD devices may be specified by their number, name, or path to the MTD character device node.\n"
1435                       "Optional \"vid_hdr_offs\" parameter specifies UBI VID header position to be used by UBI. (default value if 0)\n"
1436                       "Optional \"max_beb_per1024\" parameter specifies the maximum expected bad eraseblock per 1024 eraseblocks. (default value ("
1437                       __stringify(CONFIG_MTD_UBI_BEB_LIMIT) ") if 0)\n"
1438                       "Optional \"ubi_num\" parameter specifies UBI device number which have to be assigned to the newly created UBI device (assigned automatically by default)\n"
1439                       "\n"
1440                       "Example 1: mtd=/dev/mtd0 - attach MTD device /dev/mtd0.\n"
1441                       "Example 2: mtd=content,1984 mtd=4 - attach MTD device with name \"content\" using VID header offset 1984, and MTD device number 4 with default VID header offset.\n"
1442                       "Example 3: mtd=/dev/mtd1,0,25 - attach MTD device /dev/mtd1 using default VID header offset and reserve 25*nand_size_in_blocks/1024 erase blocks for bad block handling.\n"
1443                       "Example 4: mtd=/dev/mtd1,0,0,5 - attach MTD device /dev/mtd1 to UBI 5 and using default values for the other fields.\n"
1444                       "\t(e.g. if the NAND *chipset* has 4096 PEB, 100 will be reserved for this UBI device).");
1445 #ifdef CONFIG_MTD_UBI_FASTMAP
1446 module_param(fm_autoconvert, bool, 0644);
1447 MODULE_PARM_DESC(fm_autoconvert, "Set this parameter to enable fastmap automatically on images without a fastmap.");
1448 module_param(fm_debug, bool, 0);
1449 MODULE_PARM_DESC(fm_debug, "Set this parameter to enable fastmap debugging by default. Warning, this will make fastmap slow!");
1450 #endif
1451 MODULE_VERSION(__stringify(UBI_VERSION));
1452 MODULE_DESCRIPTION("UBI - Unsorted Block Images");
1453 MODULE_AUTHOR("Artem Bityutskiy");
1454 MODULE_LICENSE("GPL");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/mtd/ubi/build.c

DEFINITIONS
