drivers/mtd/mtdcore.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
mtd_cls_suspend
mtd_cls_resume
__mtd_next_device
mtd_release
mtd_type_show
mtd_flags_show
mtd_size_show
mtd_erasesize_show
mtd_writesize_show
mtd_subpagesize_show
mtd_oobsize_show
mtd_oobavail_show
mtd_numeraseregions_show
mtd_name_show
mtd_ecc_strength_show
mtd_bitflip_threshold_show
mtd_bitflip_threshold_store
mtd_ecc_step_size_show
mtd_ecc_stats_corrected_show
mtd_ecc_stats_errors_show
mtd_badblocks_show
mtd_bbtblocks_show
mtd_partid_show
mtd_partid_debugfs_open
mtd_partname_show
mtd_partname_debugfs_open
mtd_debugfs_populate
mtd_mmap_capabilities
mtd_reboot_notifier
mtd_wunit_to_pairing_info
mtd_pairing_info_to_wunit
mtd_pairing_groups
mtd_nvmem_reg_read
mtd_nvmem_add
add_mtd_device
del_mtd_device
mtd_set_dev_defaults
mtd_device_parse_register
mtd_device_unregister
register_mtd_user
unregister_mtd_user
get_mtd_device
__get_mtd_device
get_mtd_device_nm
put_mtd_device
__put_mtd_device
mtd_erase
mtd_point
mtd_unpoint
mtd_get_unmapped_area
mtd_read
mtd_write
mtd_panic_write
mtd_check_oob_ops
mtd_read_oob
mtd_write_oob
mtd_ooblayout_ecc
mtd_ooblayout_free
mtd_ooblayout_find_region
mtd_ooblayout_find_eccregion
mtd_ooblayout_get_bytes
mtd_ooblayout_set_bytes
mtd_ooblayout_count_bytes
mtd_ooblayout_get_eccbytes
mtd_ooblayout_set_eccbytes
mtd_ooblayout_get_databytes
mtd_ooblayout_set_databytes
mtd_ooblayout_count_freebytes
mtd_ooblayout_count_eccbytes
mtd_get_fact_prot_info
mtd_read_fact_prot_reg
mtd_get_user_prot_info
mtd_read_user_prot_reg
mtd_write_user_prot_reg
mtd_lock_user_prot_reg
mtd_lock
mtd_unlock
mtd_is_locked
mtd_block_isreserved
mtd_block_isbad
mtd_block_markbad
default_mtd_writev
mtd_writev
mtd_kmalloc_up_to
mtd_proc_show
mtd_bdi_init
init_mtd
cleanup_mtd
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Core registration and callback routines for MTD
   4  * drivers and users.
   5  *
   6  * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
   7  * Copyright © 2006      Red Hat UK Limited 
   8  */
   9 
  10 #include <linux/module.h>
  11 #include <linux/kernel.h>
  12 #include <linux/ptrace.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/string.h>
  15 #include <linux/timer.h>
  16 #include <linux/major.h>
  17 #include <linux/fs.h>
  18 #include <linux/err.h>
  19 #include <linux/ioctl.h>
  20 #include <linux/init.h>
  21 #include <linux/of.h>
  22 #include <linux/proc_fs.h>
  23 #include <linux/idr.h>
  24 #include <linux/backing-dev.h>
  25 #include <linux/gfp.h>
  26 #include <linux/slab.h>
  27 #include <linux/reboot.h>
  28 #include <linux/leds.h>
  29 #include <linux/debugfs.h>
  30 #include <linux/nvmem-provider.h>
  31 
  32 #include <linux/mtd/mtd.h>
  33 #include <linux/mtd/partitions.h>
  34 
  35 #include "mtdcore.h"
  36 
  37 struct backing_dev_info *mtd_bdi;
  38 
  39 #ifdef CONFIG_PM_SLEEP
  40 
  41 static int mtd_cls_suspend(struct device *dev)
  42 {
  43         struct mtd_info *mtd = dev_get_drvdata(dev);
  44 
  45         return mtd ? mtd_suspend(mtd) : 0;
  46 }
  47 
  48 static int mtd_cls_resume(struct device *dev)
  49 {
  50         struct mtd_info *mtd = dev_get_drvdata(dev);
  51 
  52         if (mtd)
  53                 mtd_resume(mtd);
  54         return 0;
  55 }
  56 
  57 static SIMPLE_DEV_PM_OPS(mtd_cls_pm_ops, mtd_cls_suspend, mtd_cls_resume);
  58 #define MTD_CLS_PM_OPS (&mtd_cls_pm_ops)
  59 #else
  60 #define MTD_CLS_PM_OPS NULL
  61 #endif
  62 
  63 static struct class mtd_class = {
  64         .name = "mtd",
  65         .owner = THIS_MODULE,
  66         .pm = MTD_CLS_PM_OPS,
  67 };
  68 
  69 static DEFINE_IDR(mtd_idr);
  70 
  71 /* These are exported solely for the purpose of mtd_blkdevs.c. You
  72    should not use them for _anything_ else */
  73 DEFINE_MUTEX(mtd_table_mutex);
  74 EXPORT_SYMBOL_GPL(mtd_table_mutex);
  75 
  76 struct mtd_info *__mtd_next_device(int i)
  77 {
  78         return idr_get_next(&mtd_idr, &i);
  79 }
  80 EXPORT_SYMBOL_GPL(__mtd_next_device);
  81 
  82 static LIST_HEAD(mtd_notifiers);
  83 
  84 
  85 #define MTD_DEVT(index) MKDEV(MTD_CHAR_MAJOR, (index)*2)
  86 
  87 /* REVISIT once MTD uses the driver model better, whoever allocates
  88  * the mtd_info will probably want to use the release() hook...
  89  */
  90 static void mtd_release(struct device *dev)
  91 {
  92         struct mtd_info *mtd = dev_get_drvdata(dev);
  93         dev_t index = MTD_DEVT(mtd->index);
  94 
  95         /* remove /dev/mtdXro node */
  96         device_destroy(&mtd_class, index + 1);
  97 }
  98 
  99 static ssize_t mtd_type_show(struct device *dev,
 100                 struct device_attribute *attr, char *buf)
 101 {
 102         struct mtd_info *mtd = dev_get_drvdata(dev);
 103         char *type;
 104 
 105         switch (mtd->type) {
 106         case MTD_ABSENT:
 107                 type = "absent";
 108                 break;
 109         case MTD_RAM:
 110                 type = "ram";
 111                 break;
 112         case MTD_ROM:
 113                 type = "rom";
 114                 break;
 115         case MTD_NORFLASH:
 116                 type = "nor";
 117                 break;
 118         case MTD_NANDFLASH:
 119                 type = "nand";
 120                 break;
 121         case MTD_DATAFLASH:
 122                 type = "dataflash";
 123                 break;
 124         case MTD_UBIVOLUME:
 125                 type = "ubi";
 126                 break;
 127         case MTD_MLCNANDFLASH:
 128                 type = "mlc-nand";
 129                 break;
 130         default:
 131                 type = "unknown";
 132         }
 133 
 134         return snprintf(buf, PAGE_SIZE, "%s\n", type);
 135 }
 136 static DEVICE_ATTR(type, S_IRUGO, mtd_type_show, NULL);
 137 
 138 static ssize_t mtd_flags_show(struct device *dev,
 139                 struct device_attribute *attr, char *buf)
 140 {
 141         struct mtd_info *mtd = dev_get_drvdata(dev);
 142 
 143         return snprintf(buf, PAGE_SIZE, "0x%lx\n", (unsigned long)mtd->flags);
 144 }
 145 static DEVICE_ATTR(flags, S_IRUGO, mtd_flags_show, NULL);
 146 
 147 static ssize_t mtd_size_show(struct device *dev,
 148                 struct device_attribute *attr, char *buf)
 149 {
 150         struct mtd_info *mtd = dev_get_drvdata(dev);
 151 
 152         return snprintf(buf, PAGE_SIZE, "%llu\n",
 153                 (unsigned long long)mtd->size);
 154 }
 155 static DEVICE_ATTR(size, S_IRUGO, mtd_size_show, NULL);
 156 
 157 static ssize_t mtd_erasesize_show(struct device *dev,
 158                 struct device_attribute *attr, char *buf)
 159 {
 160         struct mtd_info *mtd = dev_get_drvdata(dev);
 161 
 162         return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->erasesize);
 163 }
 164 static DEVICE_ATTR(erasesize, S_IRUGO, mtd_erasesize_show, NULL);
 165 
 166 static ssize_t mtd_writesize_show(struct device *dev,
 167                 struct device_attribute *attr, char *buf)
 168 {
 169         struct mtd_info *mtd = dev_get_drvdata(dev);
 170 
 171         return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->writesize);
 172 }
 173 static DEVICE_ATTR(writesize, S_IRUGO, mtd_writesize_show, NULL);
 174 
 175 static ssize_t mtd_subpagesize_show(struct device *dev,
 176                 struct device_attribute *attr, char *buf)
 177 {
 178         struct mtd_info *mtd = dev_get_drvdata(dev);
 179         unsigned int subpagesize = mtd->writesize >> mtd->subpage_sft;
 180 
 181         return snprintf(buf, PAGE_SIZE, "%u\n", subpagesize);
 182 }
 183 static DEVICE_ATTR(subpagesize, S_IRUGO, mtd_subpagesize_show, NULL);
 184 
 185 static ssize_t mtd_oobsize_show(struct device *dev,
 186                 struct device_attribute *attr, char *buf)
 187 {
 188         struct mtd_info *mtd = dev_get_drvdata(dev);
 189 
 190         return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->oobsize);
 191 }
 192 static DEVICE_ATTR(oobsize, S_IRUGO, mtd_oobsize_show, NULL);
 193 
 194 static ssize_t mtd_oobavail_show(struct device *dev,
 195                                  struct device_attribute *attr, char *buf)
 196 {
 197         struct mtd_info *mtd = dev_get_drvdata(dev);
 198 
 199         return snprintf(buf, PAGE_SIZE, "%u\n", mtd->oobavail);
 200 }
 201 static DEVICE_ATTR(oobavail, S_IRUGO, mtd_oobavail_show, NULL);
 202 
 203 static ssize_t mtd_numeraseregions_show(struct device *dev,
 204                 struct device_attribute *attr, char *buf)
 205 {
 206         struct mtd_info *mtd = dev_get_drvdata(dev);
 207 
 208         return snprintf(buf, PAGE_SIZE, "%u\n", mtd->numeraseregions);
 209 }
 210 static DEVICE_ATTR(numeraseregions, S_IRUGO, mtd_numeraseregions_show,
 211         NULL);
 212 
 213 static ssize_t mtd_name_show(struct device *dev,
 214                 struct device_attribute *attr, char *buf)
 215 {
 216         struct mtd_info *mtd = dev_get_drvdata(dev);
 217 
 218         return snprintf(buf, PAGE_SIZE, "%s\n", mtd->name);
 219 }
 220 static DEVICE_ATTR(name, S_IRUGO, mtd_name_show, NULL);
 221 
 222 static ssize_t mtd_ecc_strength_show(struct device *dev,
 223                                      struct device_attribute *attr, char *buf)
 224 {
 225         struct mtd_info *mtd = dev_get_drvdata(dev);
 226 
 227         return snprintf(buf, PAGE_SIZE, "%u\n", mtd->ecc_strength);
 228 }
 229 static DEVICE_ATTR(ecc_strength, S_IRUGO, mtd_ecc_strength_show, NULL);
 230 
 231 static ssize_t mtd_bitflip_threshold_show(struct device *dev,
 232                                           struct device_attribute *attr,
 233                                           char *buf)
 234 {
 235         struct mtd_info *mtd = dev_get_drvdata(dev);
 236 
 237         return snprintf(buf, PAGE_SIZE, "%u\n", mtd->bitflip_threshold);
 238 }
 239 
 240 static ssize_t mtd_bitflip_threshold_store(struct device *dev,
 241                                            struct device_attribute *attr,
 242                                            const char *buf, size_t count)
 243 {
 244         struct mtd_info *mtd = dev_get_drvdata(dev);
 245         unsigned int bitflip_threshold;
 246         int retval;
 247 
 248         retval = kstrtouint(buf, 0, &bitflip_threshold);
 249         if (retval)
 250                 return retval;
 251 
 252         mtd->bitflip_threshold = bitflip_threshold;
 253         return count;
 254 }
 255 static DEVICE_ATTR(bitflip_threshold, S_IRUGO | S_IWUSR,
 256                    mtd_bitflip_threshold_show,
 257                    mtd_bitflip_threshold_store);
 258 
 259 static ssize_t mtd_ecc_step_size_show(struct device *dev,
 260                 struct device_attribute *attr, char *buf)
 261 {
 262         struct mtd_info *mtd = dev_get_drvdata(dev);
 263 
 264         return snprintf(buf, PAGE_SIZE, "%u\n", mtd->ecc_step_size);
 265 
 266 }
 267 static DEVICE_ATTR(ecc_step_size, S_IRUGO, mtd_ecc_step_size_show, NULL);
 268 
 269 static ssize_t mtd_ecc_stats_corrected_show(struct device *dev,
 270                 struct device_attribute *attr, char *buf)
 271 {
 272         struct mtd_info *mtd = dev_get_drvdata(dev);
 273         struct mtd_ecc_stats *ecc_stats = &mtd->ecc_stats;
 274 
 275         return snprintf(buf, PAGE_SIZE, "%u\n", ecc_stats->corrected);
 276 }
 277 static DEVICE_ATTR(corrected_bits, S_IRUGO,
 278                    mtd_ecc_stats_corrected_show, NULL);
 279 
 280 static ssize_t mtd_ecc_stats_errors_show(struct device *dev,
 281                 struct device_attribute *attr, char *buf)
 282 {
 283         struct mtd_info *mtd = dev_get_drvdata(dev);
 284         struct mtd_ecc_stats *ecc_stats = &mtd->ecc_stats;
 285 
 286         return snprintf(buf, PAGE_SIZE, "%u\n", ecc_stats->failed);
 287 }
 288 static DEVICE_ATTR(ecc_failures, S_IRUGO, mtd_ecc_stats_errors_show, NULL);
 289 
 290 static ssize_t mtd_badblocks_show(struct device *dev,
 291                 struct device_attribute *attr, char *buf)
 292 {
 293         struct mtd_info *mtd = dev_get_drvdata(dev);
 294         struct mtd_ecc_stats *ecc_stats = &mtd->ecc_stats;
 295 
 296         return snprintf(buf, PAGE_SIZE, "%u\n", ecc_stats->badblocks);
 297 }
 298 static DEVICE_ATTR(bad_blocks, S_IRUGO, mtd_badblocks_show, NULL);
 299 
 300 static ssize_t mtd_bbtblocks_show(struct device *dev,
 301                 struct device_attribute *attr, char *buf)
 302 {
 303         struct mtd_info *mtd = dev_get_drvdata(dev);
 304         struct mtd_ecc_stats *ecc_stats = &mtd->ecc_stats;
 305 
 306         return snprintf(buf, PAGE_SIZE, "%u\n", ecc_stats->bbtblocks);
 307 }
 308 static DEVICE_ATTR(bbt_blocks, S_IRUGO, mtd_bbtblocks_show, NULL);
 309 
 310 static struct attribute *mtd_attrs[] = {
 311         &dev_attr_type.attr,
 312         &dev_attr_flags.attr,
 313         &dev_attr_size.attr,
 314         &dev_attr_erasesize.attr,
 315         &dev_attr_writesize.attr,
 316         &dev_attr_subpagesize.attr,
 317         &dev_attr_oobsize.attr,
 318         &dev_attr_oobavail.attr,
 319         &dev_attr_numeraseregions.attr,
 320         &dev_attr_name.attr,
 321         &dev_attr_ecc_strength.attr,
 322         &dev_attr_ecc_step_size.attr,
 323         &dev_attr_corrected_bits.attr,
 324         &dev_attr_ecc_failures.attr,
 325         &dev_attr_bad_blocks.attr,
 326         &dev_attr_bbt_blocks.attr,
 327         &dev_attr_bitflip_threshold.attr,
 328         NULL,
 329 };
 330 ATTRIBUTE_GROUPS(mtd);
 331 
 332 static const struct device_type mtd_devtype = {
 333         .name           = "mtd",
 334         .groups         = mtd_groups,
 335         .release        = mtd_release,
 336 };
 337 
 338 static int mtd_partid_show(struct seq_file *s, void *p)
 339 {
 340         struct mtd_info *mtd = s->private;
 341 
 342         seq_printf(s, "%s\n", mtd->dbg.partid);
 343 
 344         return 0;
 345 }
 346 
 347 static int mtd_partid_debugfs_open(struct inode *inode, struct file *file)
 348 {
 349         return single_open(file, mtd_partid_show, inode->i_private);
 350 }
 351 
 352 static const struct file_operations mtd_partid_debug_fops = {
 353         .open           = mtd_partid_debugfs_open,
 354         .read           = seq_read,
 355         .llseek         = seq_lseek,
 356         .release        = single_release,
 357 };
 358 
 359 static int mtd_partname_show(struct seq_file *s, void *p)
 360 {
 361         struct mtd_info *mtd = s->private;
 362 
 363         seq_printf(s, "%s\n", mtd->dbg.partname);
 364 
 365         return 0;
 366 }
 367 
 368 static int mtd_partname_debugfs_open(struct inode *inode, struct file *file)
 369 {
 370         return single_open(file, mtd_partname_show, inode->i_private);
 371 }
 372 
 373 static const struct file_operations mtd_partname_debug_fops = {
 374         .open           = mtd_partname_debugfs_open,
 375         .read           = seq_read,
 376         .llseek         = seq_lseek,
 377         .release        = single_release,
 378 };
 379 
 380 static struct dentry *dfs_dir_mtd;
 381 
 382 static void mtd_debugfs_populate(struct mtd_info *mtd)
 383 {
 384         struct device *dev = &mtd->dev;
 385         struct dentry *root, *dent;
 386 
 387         if (IS_ERR_OR_NULL(dfs_dir_mtd))
 388                 return;
 389 
 390         root = debugfs_create_dir(dev_name(dev), dfs_dir_mtd);
 391         if (IS_ERR_OR_NULL(root)) {
 392                 dev_dbg(dev, "won't show data in debugfs\n");
 393                 return;
 394         }
 395 
 396         mtd->dbg.dfs_dir = root;
 397 
 398         if (mtd->dbg.partid) {
 399                 dent = debugfs_create_file("partid", 0400, root, mtd,
 400                                            &mtd_partid_debug_fops);
 401                 if (IS_ERR_OR_NULL(dent))
 402                         dev_err(dev, "can't create debugfs entry for partid\n");
 403         }
 404 
 405         if (mtd->dbg.partname) {
 406                 dent = debugfs_create_file("partname", 0400, root, mtd,
 407                                            &mtd_partname_debug_fops);
 408                 if (IS_ERR_OR_NULL(dent))
 409                         dev_err(dev,
 410                                 "can't create debugfs entry for partname\n");
 411         }
 412 }
 413 
 414 #ifndef CONFIG_MMU
 415 unsigned mtd_mmap_capabilities(struct mtd_info *mtd)
 416 {
 417         switch (mtd->type) {
 418         case MTD_RAM:
 419                 return NOMMU_MAP_COPY | NOMMU_MAP_DIRECT | NOMMU_MAP_EXEC |
 420                         NOMMU_MAP_READ | NOMMU_MAP_WRITE;
 421         case MTD_ROM:
 422                 return NOMMU_MAP_COPY | NOMMU_MAP_DIRECT | NOMMU_MAP_EXEC |
 423                         NOMMU_MAP_READ;
 424         default:
 425                 return NOMMU_MAP_COPY;
 426         }
 427 }
 428 EXPORT_SYMBOL_GPL(mtd_mmap_capabilities);
 429 #endif
 430 
 431 static int mtd_reboot_notifier(struct notifier_block *n, unsigned long state,
 432                                void *cmd)
 433 {
 434         struct mtd_info *mtd;
 435 
 436         mtd = container_of(n, struct mtd_info, reboot_notifier);
 437         mtd->_reboot(mtd);
 438 
 439         return NOTIFY_DONE;
 440 }
 441 
 442 /**
 443  * mtd_wunit_to_pairing_info - get pairing information of a wunit
 444  * @mtd: pointer to new MTD device info structure
 445  * @wunit: write unit we are interested in
 446  * @info: returned pairing information
 447  *
 448  * Retrieve pairing information associated to the wunit.
 449  * This is mainly useful when dealing with MLC/TLC NANDs where pages can be
 450  * paired together, and where programming a page may influence the page it is
 451  * paired with.
 452  * The notion of page is replaced by the term wunit (write-unit) to stay
 453  * consistent with the ->writesize field.
 454  *
 455  * The @wunit argument can be extracted from an absolute offset using
 456  * mtd_offset_to_wunit(). @info is filled with the pairing information attached
 457  * to @wunit.
 458  *
 459  * From the pairing info the MTD user can find all the wunits paired with
 460  * @wunit using the following loop:
 461  *
 462  * for (i = 0; i < mtd_pairing_groups(mtd); i++) {
 463  *      info.pair = i;
 464  *      mtd_pairing_info_to_wunit(mtd, &info);
 465  *      ...
 466  * }
 467  */
 468 int mtd_wunit_to_pairing_info(struct mtd_info *mtd, int wunit,
 469                               struct mtd_pairing_info *info)
 470 {
 471         int npairs = mtd_wunit_per_eb(mtd) / mtd_pairing_groups(mtd);
 472 
 473         if (wunit < 0 || wunit >= npairs)
 474                 return -EINVAL;
 475 
 476         if (mtd->pairing && mtd->pairing->get_info)
 477                 return mtd->pairing->get_info(mtd, wunit, info);
 478 
 479         info->group = 0;
 480         info->pair = wunit;
 481 
 482         return 0;
 483 }
 484 EXPORT_SYMBOL_GPL(mtd_wunit_to_pairing_info);
 485 
 486 /**
 487  * mtd_pairing_info_to_wunit - get wunit from pairing information
 488  * @mtd: pointer to new MTD device info structure
 489  * @info: pairing information struct
 490  *
 491  * Returns a positive number representing the wunit associated to the info
 492  * struct, or a negative error code.
 493  *
 494  * This is the reverse of mtd_wunit_to_pairing_info(), and can help one to
 495  * iterate over all wunits of a given pair (see mtd_wunit_to_pairing_info()
 496  * doc).
 497  *
 498  * It can also be used to only program the first page of each pair (i.e.
 499  * page attached to group 0), which allows one to use an MLC NAND in
 500  * software-emulated SLC mode:
 501  *
 502  * info.group = 0;
 503  * npairs = mtd_wunit_per_eb(mtd) / mtd_pairing_groups(mtd);
 504  * for (info.pair = 0; info.pair < npairs; info.pair++) {
 505  *      wunit = mtd_pairing_info_to_wunit(mtd, &info);
 506  *      mtd_write(mtd, mtd_wunit_to_offset(mtd, blkoffs, wunit),
 507  *                mtd->writesize, &retlen, buf + (i * mtd->writesize));
 508  * }
 509  */
 510 int mtd_pairing_info_to_wunit(struct mtd_info *mtd,
 511                               const struct mtd_pairing_info *info)
 512 {
 513         int ngroups = mtd_pairing_groups(mtd);
 514         int npairs = mtd_wunit_per_eb(mtd) / ngroups;
 515 
 516         if (!info || info->pair < 0 || info->pair >= npairs ||
 517             info->group < 0 || info->group >= ngroups)
 518                 return -EINVAL;
 519 
 520         if (mtd->pairing && mtd->pairing->get_wunit)
 521                 return mtd->pairing->get_wunit(mtd, info);
 522 
 523         return info->pair;
 524 }
 525 EXPORT_SYMBOL_GPL(mtd_pairing_info_to_wunit);
 526 
 527 /**
 528  * mtd_pairing_groups - get the number of pairing groups
 529  * @mtd: pointer to new MTD device info structure
 530  *
 531  * Returns the number of pairing groups.
 532  *
 533  * This number is usually equal to the number of bits exposed by a single
 534  * cell, and can be used in conjunction with mtd_pairing_info_to_wunit()
 535  * to iterate over all pages of a given pair.
 536  */
 537 int mtd_pairing_groups(struct mtd_info *mtd)
 538 {
 539         if (!mtd->pairing || !mtd->pairing->ngroups)
 540                 return 1;
 541 
 542         return mtd->pairing->ngroups;
 543 }
 544 EXPORT_SYMBOL_GPL(mtd_pairing_groups);
 545 
 546 static int mtd_nvmem_reg_read(void *priv, unsigned int offset,
 547                               void *val, size_t bytes)
 548 {
 549         struct mtd_info *mtd = priv;
 550         size_t retlen;
 551         int err;
 552 
 553         err = mtd_read(mtd, offset, bytes, &retlen, val);
 554         if (err && err != -EUCLEAN)
 555                 return err;
 556 
 557         return retlen == bytes ? 0 : -EIO;
 558 }
 559 
 560 static int mtd_nvmem_add(struct mtd_info *mtd)
 561 {
 562         struct nvmem_config config = {};
 563 
 564         config.id = -1;
 565         config.dev = &mtd->dev;
 566         config.name = dev_name(&mtd->dev);
 567         config.owner = THIS_MODULE;
 568         config.reg_read = mtd_nvmem_reg_read;
 569         config.size = mtd->size;
 570         config.word_size = 1;
 571         config.stride = 1;
 572         config.read_only = true;
 573         config.root_only = true;
 574         config.no_of_node = true;
 575         config.priv = mtd;
 576 
 577         mtd->nvmem = nvmem_register(&config);
 578         if (IS_ERR(mtd->nvmem)) {
 579                 /* Just ignore if there is no NVMEM support in the kernel */
 580                 if (PTR_ERR(mtd->nvmem) == -EOPNOTSUPP) {
 581                         mtd->nvmem = NULL;
 582                 } else {
 583                         dev_err(&mtd->dev, "Failed to register NVMEM device\n");
 584                         return PTR_ERR(mtd->nvmem);
 585                 }
 586         }
 587 
 588         return 0;
 589 }
 590 
 591 /**
 592  *      add_mtd_device - register an MTD device
 593  *      @mtd: pointer to new MTD device info structure
 594  *
 595  *      Add a device to the list of MTD devices present in the system, and
 596  *      notify each currently active MTD 'user' of its arrival. Returns
 597  *      zero on success or non-zero on failure.
 598  */
 599 
 600 int add_mtd_device(struct mtd_info *mtd)
 601 {
 602         struct mtd_notifier *not;
 603         int i, error;
 604 
 605         /*
 606          * May occur, for instance, on buggy drivers which call
 607          * mtd_device_parse_register() multiple times on the same master MTD,
 608          * especially with CONFIG_MTD_PARTITIONED_MASTER=y.
 609          */
 610         if (WARN_ONCE(mtd->dev.type, "MTD already registered\n"))
 611                 return -EEXIST;
 612 
 613         BUG_ON(mtd->writesize == 0);
 614 
 615         /*
 616          * MTD drivers should implement ->_{write,read}() or
 617          * ->_{write,read}_oob(), but not both.
 618          */
 619         if (WARN_ON((mtd->_write && mtd->_write_oob) ||
 620                     (mtd->_read && mtd->_read_oob)))
 621                 return -EINVAL;
 622 
 623         if (WARN_ON((!mtd->erasesize || !mtd->_erase) &&
 624                     !(mtd->flags & MTD_NO_ERASE)))
 625                 return -EINVAL;
 626 
 627         mutex_lock(&mtd_table_mutex);
 628 
 629         i = idr_alloc(&mtd_idr, mtd, 0, 0, GFP_KERNEL);
 630         if (i < 0) {
 631                 error = i;
 632                 goto fail_locked;
 633         }
 634 
 635         mtd->index = i;
 636         mtd->usecount = 0;
 637 
 638         /* default value if not set by driver */
 639         if (mtd->bitflip_threshold == 0)
 640                 mtd->bitflip_threshold = mtd->ecc_strength;
 641 
 642         if (is_power_of_2(mtd->erasesize))
 643                 mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
 644         else
 645                 mtd->erasesize_shift = 0;
 646 
 647         if (is_power_of_2(mtd->writesize))
 648                 mtd->writesize_shift = ffs(mtd->writesize) - 1;
 649         else
 650                 mtd->writesize_shift = 0;
 651 
 652         mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
 653         mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;
 654 
 655         /* Some chips always power up locked. Unlock them now */
 656         if ((mtd->flags & MTD_WRITEABLE) && (mtd->flags & MTD_POWERUP_LOCK)) {
 657                 error = mtd_unlock(mtd, 0, mtd->size);
 658                 if (error && error != -EOPNOTSUPP)
 659                         printk(KERN_WARNING
 660                                "%s: unlock failed, writes may not work\n",
 661                                mtd->name);
 662                 /* Ignore unlock failures? */
 663                 error = 0;
 664         }
 665 
 666         /* Caller should have set dev.parent to match the
 667          * physical device, if appropriate.
 668          */
 669         mtd->dev.type = &mtd_devtype;
 670         mtd->dev.class = &mtd_class;
 671         mtd->dev.devt = MTD_DEVT(i);
 672         dev_set_name(&mtd->dev, "mtd%d", i);
 673         dev_set_drvdata(&mtd->dev, mtd);
 674         of_node_get(mtd_get_of_node(mtd));
 675         error = device_register(&mtd->dev);
 676         if (error)
 677                 goto fail_added;
 678 
 679         /* Add the nvmem provider */
 680         error = mtd_nvmem_add(mtd);
 681         if (error)
 682                 goto fail_nvmem_add;
 683 
 684         mtd_debugfs_populate(mtd);
 685 
 686         device_create(&mtd_class, mtd->dev.parent, MTD_DEVT(i) + 1, NULL,
 687                       "mtd%dro", i);
 688 
 689         pr_debug("mtd: Giving out device %d to %s\n", i, mtd->name);
 690         /* No need to get a refcount on the module containing
 691            the notifier, since we hold the mtd_table_mutex */
 692         list_for_each_entry(not, &mtd_notifiers, list)
 693                 not->add(mtd);
 694 
 695         mutex_unlock(&mtd_table_mutex);
 696         /* We _know_ we aren't being removed, because
 697            our caller is still holding us here. So none
 698            of this try_ nonsense, and no bitching about it
 699            either. :) */
 700         __module_get(THIS_MODULE);
 701         return 0;
 702 
 703 fail_nvmem_add:
 704         device_unregister(&mtd->dev);
 705 fail_added:
 706         of_node_put(mtd_get_of_node(mtd));
 707         idr_remove(&mtd_idr, i);
 708 fail_locked:
 709         mutex_unlock(&mtd_table_mutex);
 710         return error;
 711 }
 712 
 713 /**
 714  *      del_mtd_device - unregister an MTD device
 715  *      @mtd: pointer to MTD device info structure
 716  *
 717  *      Remove a device from the list of MTD devices present in the system,
 718  *      and notify each currently active MTD 'user' of its departure.
 719  *      Returns zero on success or 1 on failure, which currently will happen
 720  *      if the requested device does not appear to be present in the list.
 721  */
 722 
 723 int del_mtd_device(struct mtd_info *mtd)
 724 {
 725         int ret;
 726         struct mtd_notifier *not;
 727 
 728         mutex_lock(&mtd_table_mutex);
 729 
 730         debugfs_remove_recursive(mtd->dbg.dfs_dir);
 731 
 732         if (idr_find(&mtd_idr, mtd->index) != mtd) {
 733                 ret = -ENODEV;
 734                 goto out_error;
 735         }
 736 
 737         /* No need to get a refcount on the module containing
 738                 the notifier, since we hold the mtd_table_mutex */
 739         list_for_each_entry(not, &mtd_notifiers, list)
 740                 not->remove(mtd);
 741 
 742         if (mtd->usecount) {
 743                 printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
 744                        mtd->index, mtd->name, mtd->usecount);
 745                 ret = -EBUSY;
 746         } else {
 747                 /* Try to remove the NVMEM provider */
 748                 if (mtd->nvmem)
 749                         nvmem_unregister(mtd->nvmem);
 750 
 751                 device_unregister(&mtd->dev);
 752 
 753                 idr_remove(&mtd_idr, mtd->index);
 754                 of_node_put(mtd_get_of_node(mtd));
 755 
 756                 module_put(THIS_MODULE);
 757                 ret = 0;
 758         }
 759 
 760 out_error:
 761         mutex_unlock(&mtd_table_mutex);
 762         return ret;
 763 }
 764 
 765 /*
 766  * Set a few defaults based on the parent devices, if not provided by the
 767  * driver
 768  */
 769 static void mtd_set_dev_defaults(struct mtd_info *mtd)
 770 {
 771         if (mtd->dev.parent) {
 772                 if (!mtd->owner && mtd->dev.parent->driver)
 773                         mtd->owner = mtd->dev.parent->driver->owner;
 774                 if (!mtd->name)
 775                         mtd->name = dev_name(mtd->dev.parent);
 776         } else {
 777                 pr_debug("mtd device won't show a device symlink in sysfs\n");
 778         }
 779 
 780         mtd->orig_flags = mtd->flags;
 781 }
 782 
 783 /**
 784  * mtd_device_parse_register - parse partitions and register an MTD device.
 785  *
 786  * @mtd: the MTD device to register
 787  * @types: the list of MTD partition probes to try, see
 788  *         'parse_mtd_partitions()' for more information
 789  * @parser_data: MTD partition parser-specific data
 790  * @parts: fallback partition information to register, if parsing fails;
 791  *         only valid if %nr_parts > %0
 792  * @nr_parts: the number of partitions in parts, if zero then the full
 793  *            MTD device is registered if no partition info is found
 794  *
 795  * This function aggregates MTD partitions parsing (done by
 796  * 'parse_mtd_partitions()') and MTD device and partitions registering. It
 797  * basically follows the most common pattern found in many MTD drivers:
 798  *
 799  * * If the MTD_PARTITIONED_MASTER option is set, then the device as a whole is
 800  *   registered first.
 801  * * Then It tries to probe partitions on MTD device @mtd using parsers
 802  *   specified in @types (if @types is %NULL, then the default list of parsers
 803  *   is used, see 'parse_mtd_partitions()' for more information). If none are
 804  *   found this functions tries to fallback to information specified in
 805  *   @parts/@nr_parts.
 806  * * If no partitions were found this function just registers the MTD device
 807  *   @mtd and exits.
 808  *
 809  * Returns zero in case of success and a negative error code in case of failure.
 810  */
 811 int mtd_device_parse_register(struct mtd_info *mtd, const char * const *types,
 812                               struct mtd_part_parser_data *parser_data,
 813                               const struct mtd_partition *parts,
 814                               int nr_parts)
 815 {
 816         int ret;
 817 
 818         mtd_set_dev_defaults(mtd);
 819 
 820         if (IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER)) {
 821                 ret = add_mtd_device(mtd);
 822                 if (ret)
 823                         return ret;
 824         }
 825 
 826         /* Prefer parsed partitions over driver-provided fallback */
 827         ret = parse_mtd_partitions(mtd, types, parser_data);
 828         if (ret > 0)
 829                 ret = 0;
 830         else if (nr_parts)
 831                 ret = add_mtd_partitions(mtd, parts, nr_parts);
 832         else if (!device_is_registered(&mtd->dev))
 833                 ret = add_mtd_device(mtd);
 834         else
 835                 ret = 0;
 836 
 837         if (ret)
 838                 goto out;
 839 
 840         /*
 841          * FIXME: some drivers unfortunately call this function more than once.
 842          * So we have to check if we've already assigned the reboot notifier.
 843          *
 844          * Generally, we can make multiple calls work for most cases, but it
 845          * does cause problems with parse_mtd_partitions() above (e.g.,
 846          * cmdlineparts will register partitions more than once).
 847          */
 848         WARN_ONCE(mtd->_reboot && mtd->reboot_notifier.notifier_call,
 849                   "MTD already registered\n");
 850         if (mtd->_reboot && !mtd->reboot_notifier.notifier_call) {
 851                 mtd->reboot_notifier.notifier_call = mtd_reboot_notifier;
 852                 register_reboot_notifier(&mtd->reboot_notifier);
 853         }
 854 
 855 out:
 856         if (ret && device_is_registered(&mtd->dev))
 857                 del_mtd_device(mtd);
 858 
 859         return ret;
 860 }
 861 EXPORT_SYMBOL_GPL(mtd_device_parse_register);
 862 
 863 /**
 864  * mtd_device_unregister - unregister an existing MTD device.
 865  *
 866  * @master: the MTD device to unregister.  This will unregister both the master
 867  *          and any partitions if registered.
 868  */
 869 int mtd_device_unregister(struct mtd_info *master)
 870 {
 871         int err;
 872 
 873         if (master->_reboot)
 874                 unregister_reboot_notifier(&master->reboot_notifier);
 875 
 876         err = del_mtd_partitions(master);
 877         if (err)
 878                 return err;
 879 
 880         if (!device_is_registered(&master->dev))
 881                 return 0;
 882 
 883         return del_mtd_device(master);
 884 }
 885 EXPORT_SYMBOL_GPL(mtd_device_unregister);
 886 
 887 /**
 888  *      register_mtd_user - register a 'user' of MTD devices.
 889  *      @new: pointer to notifier info structure
 890  *
 891  *      Registers a pair of callbacks function to be called upon addition
 892  *      or removal of MTD devices. Causes the 'add' callback to be immediately
 893  *      invoked for each MTD device currently present in the system.
 894  */
 895 void register_mtd_user (struct mtd_notifier *new)
 896 {
 897         struct mtd_info *mtd;
 898 
 899         mutex_lock(&mtd_table_mutex);
 900 
 901         list_add(&new->list, &mtd_notifiers);
 902 
 903         __module_get(THIS_MODULE);
 904 
 905         mtd_for_each_device(mtd)
 906                 new->add(mtd);
 907 
 908         mutex_unlock(&mtd_table_mutex);
 909 }
 910 EXPORT_SYMBOL_GPL(register_mtd_user);
 911 
 912 /**
 913  *      unregister_mtd_user - unregister a 'user' of MTD devices.
 914  *      @old: pointer to notifier info structure
 915  *
 916  *      Removes a callback function pair from the list of 'users' to be
 917  *      notified upon addition or removal of MTD devices. Causes the
 918  *      'remove' callback to be immediately invoked for each MTD device
 919  *      currently present in the system.
 920  */
 921 int unregister_mtd_user (struct mtd_notifier *old)
 922 {
 923         struct mtd_info *mtd;
 924 
 925         mutex_lock(&mtd_table_mutex);
 926 
 927         module_put(THIS_MODULE);
 928 
 929         mtd_for_each_device(mtd)
 930                 old->remove(mtd);
 931 
 932         list_del(&old->list);
 933         mutex_unlock(&mtd_table_mutex);
 934         return 0;
 935 }
 936 EXPORT_SYMBOL_GPL(unregister_mtd_user);
 937 
 938 /**
 939  *      get_mtd_device - obtain a validated handle for an MTD device
 940  *      @mtd: last known address of the required MTD device
 941  *      @num: internal device number of the required MTD device
 942  *
 943  *      Given a number and NULL address, return the num'th entry in the device
 944  *      table, if any.  Given an address and num == -1, search the device table
 945  *      for a device with that address and return if it's still present. Given
 946  *      both, return the num'th driver only if its address matches. Return
 947  *      error code if not.
 948  */
 949 struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
 950 {
 951         struct mtd_info *ret = NULL, *other;
 952         int err = -ENODEV;
 953 
 954         mutex_lock(&mtd_table_mutex);
 955 
 956         if (num == -1) {
 957                 mtd_for_each_device(other) {
 958                         if (other == mtd) {
 959                                 ret = mtd;
 960                                 break;
 961                         }
 962                 }
 963         } else if (num >= 0) {
 964                 ret = idr_find(&mtd_idr, num);
 965                 if (mtd && mtd != ret)
 966                         ret = NULL;
 967         }
 968 
 969         if (!ret) {
 970                 ret = ERR_PTR(err);
 971                 goto out;
 972         }
 973 
 974         err = __get_mtd_device(ret);
 975         if (err)
 976                 ret = ERR_PTR(err);
 977 out:
 978         mutex_unlock(&mtd_table_mutex);
 979         return ret;
 980 }
 981 EXPORT_SYMBOL_GPL(get_mtd_device);
 982 
 983 
 984 int __get_mtd_device(struct mtd_info *mtd)
 985 {
 986         int err;
 987 
 988         if (!try_module_get(mtd->owner))
 989                 return -ENODEV;
 990 
 991         if (mtd->_get_device) {
 992                 err = mtd->_get_device(mtd);
 993 
 994                 if (err) {
 995                         module_put(mtd->owner);
 996                         return err;
 997                 }
 998         }
 999         mtd->usecount++;
1000         return 0;
1001 }
1002 EXPORT_SYMBOL_GPL(__get_mtd_device);
1003 
1004 /**
1005  *      get_mtd_device_nm - obtain a validated handle for an MTD device by
1006  *      device name
1007  *      @name: MTD device name to open
1008  *
1009  *      This function returns MTD device description structure in case of
1010  *      success and an error code in case of failure.
1011  */
1012 struct mtd_info *get_mtd_device_nm(const char *name)
1013 {
1014         int err = -ENODEV;
1015         struct mtd_info *mtd = NULL, *other;
1016 
1017         mutex_lock(&mtd_table_mutex);
1018 
1019         mtd_for_each_device(other) {
1020                 if (!strcmp(name, other->name)) {
1021                         mtd = other;
1022                         break;
1023                 }
1024         }
1025 
1026         if (!mtd)
1027                 goto out_unlock;
1028 
1029         err = __get_mtd_device(mtd);
1030         if (err)
1031                 goto out_unlock;
1032 
1033         mutex_unlock(&mtd_table_mutex);
1034         return mtd;
1035 
1036 out_unlock:
1037         mutex_unlock(&mtd_table_mutex);
1038         return ERR_PTR(err);
1039 }
1040 EXPORT_SYMBOL_GPL(get_mtd_device_nm);
1041 
1042 void put_mtd_device(struct mtd_info *mtd)
1043 {
1044         mutex_lock(&mtd_table_mutex);
1045         __put_mtd_device(mtd);
1046         mutex_unlock(&mtd_table_mutex);
1047 
1048 }
1049 EXPORT_SYMBOL_GPL(put_mtd_device);
1050 
1051 void __put_mtd_device(struct mtd_info *mtd)
1052 {
1053         --mtd->usecount;
1054         BUG_ON(mtd->usecount < 0);
1055 
1056         if (mtd->_put_device)
1057                 mtd->_put_device(mtd);
1058 
1059         module_put(mtd->owner);
1060 }
1061 EXPORT_SYMBOL_GPL(__put_mtd_device);
1062 
1063 /*
1064  * Erase is an synchronous operation. Device drivers are epected to return a
1065  * negative error code if the operation failed and update instr->fail_addr
1066  * to point the portion that was not properly erased.
1067  */
1068 int mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
1069 {
1070         instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
1071 
1072         if (!mtd->erasesize || !mtd->_erase)
1073                 return -ENOTSUPP;
1074 
1075         if (instr->addr >= mtd->size || instr->len > mtd->size - instr->addr)
1076                 return -EINVAL;
1077         if (!(mtd->flags & MTD_WRITEABLE))
1078                 return -EROFS;
1079 
1080         if (!instr->len)
1081                 return 0;
1082 
1083         ledtrig_mtd_activity();
1084         return mtd->_erase(mtd, instr);
1085 }
1086 EXPORT_SYMBOL_GPL(mtd_erase);
1087 
1088 /*
1089  * This stuff for eXecute-In-Place. phys is optional and may be set to NULL.
1090  */
1091 int mtd_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
1092               void **virt, resource_size_t *phys)
1093 {
1094         *retlen = 0;
1095         *virt = NULL;
1096         if (phys)
1097                 *phys = 0;
1098         if (!mtd->_point)
1099                 return -EOPNOTSUPP;
1100         if (from < 0 || from >= mtd->size || len > mtd->size - from)
1101                 return -EINVAL;
1102         if (!len)
1103                 return 0;
1104         return mtd->_point(mtd, from, len, retlen, virt, phys);
1105 }
1106 EXPORT_SYMBOL_GPL(mtd_point);
1107 
1108 /* We probably shouldn't allow XIP if the unpoint isn't a NULL */
1109 int mtd_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
1110 {
1111         if (!mtd->_unpoint)
1112                 return -EOPNOTSUPP;
1113         if (from < 0 || from >= mtd->size || len > mtd->size - from)
1114                 return -EINVAL;
1115         if (!len)
1116                 return 0;
1117         return mtd->_unpoint(mtd, from, len);
1118 }
1119 EXPORT_SYMBOL_GPL(mtd_unpoint);
1120 
1121 /*
1122  * Allow NOMMU mmap() to directly map the device (if not NULL)
1123  * - return the address to which the offset maps
1124  * - return -ENOSYS to indicate refusal to do the mapping
1125  */
1126 unsigned long mtd_get_unmapped_area(struct mtd_info *mtd, unsigned long len,
1127                                     unsigned long offset, unsigned long flags)
1128 {
1129         size_t retlen;
1130         void *virt;
1131         int ret;
1132 
1133         ret = mtd_point(mtd, offset, len, &retlen, &virt, NULL);
1134         if (ret)
1135                 return ret;
1136         if (retlen != len) {
1137                 mtd_unpoint(mtd, offset, retlen);
1138                 return -ENOSYS;
1139         }
1140         return (unsigned long)virt;
1141 }
1142 EXPORT_SYMBOL_GPL(mtd_get_unmapped_area);
1143 
1144 int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
1145              u_char *buf)
1146 {
1147         struct mtd_oob_ops ops = {
1148                 .len = len,
1149                 .datbuf = buf,
1150         };
1151         int ret;
1152 
1153         ret = mtd_read_oob(mtd, from, &ops);
1154         *retlen = ops.retlen;
1155 
1156         return ret;
1157 }
1158 EXPORT_SYMBOL_GPL(mtd_read);
1159 
1160 int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
1161               const u_char *buf)
1162 {
1163         struct mtd_oob_ops ops = {
1164                 .len = len,
1165                 .datbuf = (u8 *)buf,
1166         };
1167         int ret;
1168 
1169         ret = mtd_write_oob(mtd, to, &ops);
1170         *retlen = ops.retlen;
1171 
1172         return ret;
1173 }
1174 EXPORT_SYMBOL_GPL(mtd_write);
1175 
1176 /*
1177  * In blackbox flight recorder like scenarios we want to make successful writes
1178  * in interrupt context. panic_write() is only intended to be called when its
1179  * known the kernel is about to panic and we need the write to succeed. Since
1180  * the kernel is not going to be running for much longer, this function can
1181  * break locks and delay to ensure the write succeeds (but not sleep).
1182  */
1183 int mtd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
1184                     const u_char *buf)
1185 {
1186         *retlen = 0;
1187         if (!mtd->_panic_write)
1188                 return -EOPNOTSUPP;
1189         if (to < 0 || to >= mtd->size || len > mtd->size - to)
1190                 return -EINVAL;
1191         if (!(mtd->flags & MTD_WRITEABLE))
1192                 return -EROFS;
1193         if (!len)
1194                 return 0;
1195         if (!mtd->oops_panic_write)
1196                 mtd->oops_panic_write = true;
1197 
1198         return mtd->_panic_write(mtd, to, len, retlen, buf);
1199 }
1200 EXPORT_SYMBOL_GPL(mtd_panic_write);
1201 
1202 static int mtd_check_oob_ops(struct mtd_info *mtd, loff_t offs,
1203                              struct mtd_oob_ops *ops)
1204 {
1205         /*
1206          * Some users are setting ->datbuf or ->oobbuf to NULL, but are leaving
1207          * ->len or ->ooblen uninitialized. Force ->len and ->ooblen to 0 in
1208          *  this case.
1209          */
1210         if (!ops->datbuf)
1211                 ops->len = 0;
1212 
1213         if (!ops->oobbuf)
1214                 ops->ooblen = 0;
1215 
1216         if (offs < 0 || offs + ops->len > mtd->size)
1217                 return -EINVAL;
1218 
1219         if (ops->ooblen) {
1220                 size_t maxooblen;
1221 
1222                 if (ops->ooboffs >= mtd_oobavail(mtd, ops))
1223                         return -EINVAL;
1224 
1225                 maxooblen = ((size_t)(mtd_div_by_ws(mtd->size, mtd) -
1226                                       mtd_div_by_ws(offs, mtd)) *
1227                              mtd_oobavail(mtd, ops)) - ops->ooboffs;
1228                 if (ops->ooblen > maxooblen)
1229                         return -EINVAL;
1230         }
1231 
1232         return 0;
1233 }
1234 
1235 int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
1236 {
1237         int ret_code;
1238         ops->retlen = ops->oobretlen = 0;
1239 
1240         ret_code = mtd_check_oob_ops(mtd, from, ops);
1241         if (ret_code)
1242                 return ret_code;
1243 
1244         ledtrig_mtd_activity();
1245 
1246         /* Check the validity of a potential fallback on mtd->_read */
1247         if (!mtd->_read_oob && (!mtd->_read || ops->oobbuf))
1248                 return -EOPNOTSUPP;
1249 
1250         if (mtd->_read_oob)
1251                 ret_code = mtd->_read_oob(mtd, from, ops);
1252         else
1253                 ret_code = mtd->_read(mtd, from, ops->len, &ops->retlen,
1254                                       ops->datbuf);
1255 
1256         /*
1257          * In cases where ops->datbuf != NULL, mtd->_read_oob() has semantics
1258          * similar to mtd->_read(), returning a non-negative integer
1259          * representing max bitflips. In other cases, mtd->_read_oob() may
1260          * return -EUCLEAN. In all cases, perform similar logic to mtd_read().
1261          */
1262         if (unlikely(ret_code < 0))
1263                 return ret_code;
1264         if (mtd->ecc_strength == 0)
1265                 return 0;       /* device lacks ecc */
1266         return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
1267 }
1268 EXPORT_SYMBOL_GPL(mtd_read_oob);
1269 
1270 int mtd_write_oob(struct mtd_info *mtd, loff_t to,
1271                                 struct mtd_oob_ops *ops)
1272 {
1273         int ret;
1274 
1275         ops->retlen = ops->oobretlen = 0;
1276 
1277         if (!(mtd->flags & MTD_WRITEABLE))
1278                 return -EROFS;
1279 
1280         ret = mtd_check_oob_ops(mtd, to, ops);
1281         if (ret)
1282                 return ret;
1283 
1284         ledtrig_mtd_activity();
1285 
1286         /* Check the validity of a potential fallback on mtd->_write */
1287         if (!mtd->_write_oob && (!mtd->_write || ops->oobbuf))
1288                 return -EOPNOTSUPP;
1289 
1290         if (mtd->_write_oob)
1291                 return mtd->_write_oob(mtd, to, ops);
1292         else
1293                 return mtd->_write(mtd, to, ops->len, &ops->retlen,
1294                                    ops->datbuf);
1295 }
1296 EXPORT_SYMBOL_GPL(mtd_write_oob);
1297 
1298 /**
1299  * mtd_ooblayout_ecc - Get the OOB region definition of a specific ECC section
1300  * @mtd: MTD device structure
1301  * @section: ECC section. Depending on the layout you may have all the ECC
1302  *           bytes stored in a single contiguous section, or one section
1303  *           per ECC chunk (and sometime several sections for a single ECC
1304  *           ECC chunk)
1305  * @oobecc: OOB region struct filled with the appropriate ECC position
1306  *          information
1307  *
1308  * This function returns ECC section information in the OOB area. If you want
1309  * to get all the ECC bytes information, then you should call
1310  * mtd_ooblayout_ecc(mtd, section++, oobecc) until it returns -ERANGE.
1311  *
1312  * Returns zero on success, a negative error code otherwise.
1313  */
1314 int mtd_ooblayout_ecc(struct mtd_info *mtd, int section,
1315                       struct mtd_oob_region *oobecc)
1316 {
1317         memset(oobecc, 0, sizeof(*oobecc));
1318 
1319         if (!mtd || section < 0)
1320                 return -EINVAL;
1321 
1322         if (!mtd->ooblayout || !mtd->ooblayout->ecc)
1323                 return -ENOTSUPP;
1324 
1325         return mtd->ooblayout->ecc(mtd, section, oobecc);
1326 }
1327 EXPORT_SYMBOL_GPL(mtd_ooblayout_ecc);
1328 
1329 /**
1330  * mtd_ooblayout_free - Get the OOB region definition of a specific free
1331  *                      section
1332  * @mtd: MTD device structure
1333  * @section: Free section you are interested in. Depending on the layout
1334  *           you may have all the free bytes stored in a single contiguous
1335  *           section, or one section per ECC chunk plus an extra section
1336  *           for the remaining bytes (or other funky layout).
1337  * @oobfree: OOB region struct filled with the appropriate free position
1338  *           information
1339  *
1340  * This function returns free bytes position in the OOB area. If you want
1341  * to get all the free bytes information, then you should call
1342  * mtd_ooblayout_free(mtd, section++, oobfree) until it returns -ERANGE.
1343  *
1344  * Returns zero on success, a negative error code otherwise.
1345  */
1346 int mtd_ooblayout_free(struct mtd_info *mtd, int section,
1347                        struct mtd_oob_region *oobfree)
1348 {
1349         memset(oobfree, 0, sizeof(*oobfree));
1350 
1351         if (!mtd || section < 0)
1352                 return -EINVAL;
1353 
1354         if (!mtd->ooblayout || !mtd->ooblayout->free)
1355                 return -ENOTSUPP;
1356 
1357         return mtd->ooblayout->free(mtd, section, oobfree);
1358 }
1359 EXPORT_SYMBOL_GPL(mtd_ooblayout_free);
1360 
1361 /**
1362  * mtd_ooblayout_find_region - Find the region attached to a specific byte
1363  * @mtd: mtd info structure
1364  * @byte: the byte we are searching for
1365  * @sectionp: pointer where the section id will be stored
1366  * @oobregion: used to retrieve the ECC position
1367  * @iter: iterator function. Should be either mtd_ooblayout_free or
1368  *        mtd_ooblayout_ecc depending on the region type you're searching for
1369  *
1370  * This function returns the section id and oobregion information of a
1371  * specific byte. For example, say you want to know where the 4th ECC byte is
1372  * stored, you'll use:
1373  *
1374  * mtd_ooblayout_find_region(mtd, 3, &section, &oobregion, mtd_ooblayout_ecc);
1375  *
1376  * Returns zero on success, a negative error code otherwise.
1377  */
1378 static int mtd_ooblayout_find_region(struct mtd_info *mtd, int byte,
1379                                 int *sectionp, struct mtd_oob_region *oobregion,
1380                                 int (*iter)(struct mtd_info *,
1381                                             int section,
1382                                             struct mtd_oob_region *oobregion))
1383 {
1384         int pos = 0, ret, section = 0;
1385 
1386         memset(oobregion, 0, sizeof(*oobregion));
1387 
1388         while (1) {
1389                 ret = iter(mtd, section, oobregion);
1390                 if (ret)
1391                         return ret;
1392 
1393                 if (pos + oobregion->length > byte)
1394                         break;
1395 
1396                 pos += oobregion->length;
1397                 section++;
1398         }
1399 
1400         /*
1401          * Adjust region info to make it start at the beginning at the
1402          * 'start' ECC byte.
1403          */
1404         oobregion->offset += byte - pos;
1405         oobregion->length -= byte - pos;
1406         *sectionp = section;
1407 
1408         return 0;
1409 }
1410 
1411 /**
1412  * mtd_ooblayout_find_eccregion - Find the ECC region attached to a specific
1413  *                                ECC byte
1414  * @mtd: mtd info structure
1415  * @eccbyte: the byte we are searching for
1416  * @sectionp: pointer where the section id will be stored
1417  * @oobregion: OOB region information
1418  *
1419  * Works like mtd_ooblayout_find_region() except it searches for a specific ECC
1420  * byte.
1421  *
1422  * Returns zero on success, a negative error code otherwise.
1423  */
1424 int mtd_ooblayout_find_eccregion(struct mtd_info *mtd, int eccbyte,
1425                                  int *section,
1426                                  struct mtd_oob_region *oobregion)
1427 {
1428         return mtd_ooblayout_find_region(mtd, eccbyte, section, oobregion,
1429                                          mtd_ooblayout_ecc);
1430 }
1431 EXPORT_SYMBOL_GPL(mtd_ooblayout_find_eccregion);
1432 
1433 /**
1434  * mtd_ooblayout_get_bytes - Extract OOB bytes from the oob buffer
1435  * @mtd: mtd info structure
1436  * @buf: destination buffer to store OOB bytes
1437  * @oobbuf: OOB buffer
1438  * @start: first byte to retrieve
1439  * @nbytes: number of bytes to retrieve
1440  * @iter: section iterator
1441  *
1442  * Extract bytes attached to a specific category (ECC or free)
1443  * from the OOB buffer and copy them into buf.
1444  *
1445  * Returns zero on success, a negative error code otherwise.
1446  */
1447 static int mtd_ooblayout_get_bytes(struct mtd_info *mtd, u8 *buf,
1448                                 const u8 *oobbuf, int start, int nbytes,
1449                                 int (*iter)(struct mtd_info *,
1450                                             int section,
1451                                             struct mtd_oob_region *oobregion))
1452 {
1453         struct mtd_oob_region oobregion;
1454         int section, ret;
1455 
1456         ret = mtd_ooblayout_find_region(mtd, start, &section,
1457                                         &oobregion, iter);
1458 
1459         while (!ret) {
1460                 int cnt;
1461 
1462                 cnt = min_t(int, nbytes, oobregion.length);
1463                 memcpy(buf, oobbuf + oobregion.offset, cnt);
1464                 buf += cnt;
1465                 nbytes -= cnt;
1466 
1467                 if (!nbytes)
1468                         break;
1469 
1470                 ret = iter(mtd, ++section, &oobregion);
1471         }
1472 
1473         return ret;
1474 }
1475 
1476 /**
1477  * mtd_ooblayout_set_bytes - put OOB bytes into the oob buffer
1478  * @mtd: mtd info structure
1479  * @buf: source buffer to get OOB bytes from
1480  * @oobbuf: OOB buffer
1481  * @start: first OOB byte to set
1482  * @nbytes: number of OOB bytes to set
1483  * @iter: section iterator
1484  *
1485  * Fill the OOB buffer with data provided in buf. The category (ECC or free)
1486  * is selected by passing the appropriate iterator.
1487  *
1488  * Returns zero on success, a negative error code otherwise.
1489  */
1490 static int mtd_ooblayout_set_bytes(struct mtd_info *mtd, const u8 *buf,
1491                                 u8 *oobbuf, int start, int nbytes,
1492                                 int (*iter)(struct mtd_info *,
1493                                             int section,
1494                                             struct mtd_oob_region *oobregion))
1495 {
1496         struct mtd_oob_region oobregion;
1497         int section, ret;
1498 
1499         ret = mtd_ooblayout_find_region(mtd, start, &section,
1500                                         &oobregion, iter);
1501 
1502         while (!ret) {
1503                 int cnt;
1504 
1505                 cnt = min_t(int, nbytes, oobregion.length);
1506                 memcpy(oobbuf + oobregion.offset, buf, cnt);
1507                 buf += cnt;
1508                 nbytes -= cnt;
1509 
1510                 if (!nbytes)
1511                         break;
1512 
1513                 ret = iter(mtd, ++section, &oobregion);
1514         }
1515 
1516         return ret;
1517 }
1518 
1519 /**
1520  * mtd_ooblayout_count_bytes - count the number of bytes in a OOB category
1521  * @mtd: mtd info structure
1522  * @iter: category iterator
1523  *
1524  * Count the number of bytes in a given category.
1525  *
1526  * Returns a positive value on success, a negative error code otherwise.
1527  */
1528 static int mtd_ooblayout_count_bytes(struct mtd_info *mtd,
1529                                 int (*iter)(struct mtd_info *,
1530                                             int section,
1531                                             struct mtd_oob_region *oobregion))
1532 {
1533         struct mtd_oob_region oobregion;
1534         int section = 0, ret, nbytes = 0;
1535 
1536         while (1) {
1537                 ret = iter(mtd, section++, &oobregion);
1538                 if (ret) {
1539                         if (ret == -ERANGE)
1540                                 ret = nbytes;
1541                         break;
1542                 }
1543 
1544                 nbytes += oobregion.length;
1545         }
1546 
1547         return ret;
1548 }
1549 
1550 /**
1551  * mtd_ooblayout_get_eccbytes - extract ECC bytes from the oob buffer
1552  * @mtd: mtd info structure
1553  * @eccbuf: destination buffer to store ECC bytes
1554  * @oobbuf: OOB buffer
1555  * @start: first ECC byte to retrieve
1556  * @nbytes: number of ECC bytes to retrieve
1557  *
1558  * Works like mtd_ooblayout_get_bytes(), except it acts on ECC bytes.
1559  *
1560  * Returns zero on success, a negative error code otherwise.
1561  */
1562 int mtd_ooblayout_get_eccbytes(struct mtd_info *mtd, u8 *eccbuf,
1563                                const u8 *oobbuf, int start, int nbytes)
1564 {
1565         return mtd_ooblayout_get_bytes(mtd, eccbuf, oobbuf, start, nbytes,
1566                                        mtd_ooblayout_ecc);
1567 }
1568 EXPORT_SYMBOL_GPL(mtd_ooblayout_get_eccbytes);
1569 
1570 /**
1571  * mtd_ooblayout_set_eccbytes - set ECC bytes into the oob buffer
1572  * @mtd: mtd info structure
1573  * @eccbuf: source buffer to get ECC bytes from
1574  * @oobbuf: OOB buffer
1575  * @start: first ECC byte to set
1576  * @nbytes: number of ECC bytes to set
1577  *
1578  * Works like mtd_ooblayout_set_bytes(), except it acts on ECC bytes.
1579  *
1580  * Returns zero on success, a negative error code otherwise.
1581  */
1582 int mtd_ooblayout_set_eccbytes(struct mtd_info *mtd, const u8 *eccbuf,
1583                                u8 *oobbuf, int start, int nbytes)
1584 {
1585         return mtd_ooblayout_set_bytes(mtd, eccbuf, oobbuf, start, nbytes,
1586                                        mtd_ooblayout_ecc);
1587 }
1588 EXPORT_SYMBOL_GPL(mtd_ooblayout_set_eccbytes);
1589 
1590 /**
1591  * mtd_ooblayout_get_databytes - extract data bytes from the oob buffer
1592  * @mtd: mtd info structure
1593  * @databuf: destination buffer to store ECC bytes
1594  * @oobbuf: OOB buffer
1595  * @start: first ECC byte to retrieve
1596  * @nbytes: number of ECC bytes to retrieve
1597  *
1598  * Works like mtd_ooblayout_get_bytes(), except it acts on free bytes.
1599  *
1600  * Returns zero on success, a negative error code otherwise.
1601  */
1602 int mtd_ooblayout_get_databytes(struct mtd_info *mtd, u8 *databuf,
1603                                 const u8 *oobbuf, int start, int nbytes)
1604 {
1605         return mtd_ooblayout_get_bytes(mtd, databuf, oobbuf, start, nbytes,
1606                                        mtd_ooblayout_free);
1607 }
1608 EXPORT_SYMBOL_GPL(mtd_ooblayout_get_databytes);
1609 
1610 /**
1611  * mtd_ooblayout_set_databytes - set data bytes into the oob buffer
1612  * @mtd: mtd info structure
1613  * @databuf: source buffer to get data bytes from
1614  * @oobbuf: OOB buffer
1615  * @start: first ECC byte to set
1616  * @nbytes: number of ECC bytes to set
1617  *
1618  * Works like mtd_ooblayout_get_bytes(), except it acts on free bytes.
1619  *
1620  * Returns zero on success, a negative error code otherwise.
1621  */
1622 int mtd_ooblayout_set_databytes(struct mtd_info *mtd, const u8 *databuf,
1623                                 u8 *oobbuf, int start, int nbytes)
1624 {
1625         return mtd_ooblayout_set_bytes(mtd, databuf, oobbuf, start, nbytes,
1626                                        mtd_ooblayout_free);
1627 }
1628 EXPORT_SYMBOL_GPL(mtd_ooblayout_set_databytes);
1629 
1630 /**
1631  * mtd_ooblayout_count_freebytes - count the number of free bytes in OOB
1632  * @mtd: mtd info structure
1633  *
1634  * Works like mtd_ooblayout_count_bytes(), except it count free bytes.
1635  *
1636  * Returns zero on success, a negative error code otherwise.
1637  */
1638 int mtd_ooblayout_count_freebytes(struct mtd_info *mtd)
1639 {
1640         return mtd_ooblayout_count_bytes(mtd, mtd_ooblayout_free);
1641 }
1642 EXPORT_SYMBOL_GPL(mtd_ooblayout_count_freebytes);
1643 
1644 /**
1645  * mtd_ooblayout_count_eccbytes - count the number of ECC bytes in OOB
1646  * @mtd: mtd info structure
1647  *
1648  * Works like mtd_ooblayout_count_bytes(), except it count ECC bytes.
1649  *
1650  * Returns zero on success, a negative error code otherwise.
1651  */
1652 int mtd_ooblayout_count_eccbytes(struct mtd_info *mtd)
1653 {
1654         return mtd_ooblayout_count_bytes(mtd, mtd_ooblayout_ecc);
1655 }
1656 EXPORT_SYMBOL_GPL(mtd_ooblayout_count_eccbytes);
1657 
1658 /*
1659  * Method to access the protection register area, present in some flash
1660  * devices. The user data is one time programmable but the factory data is read
1661  * only.
1662  */
1663 int mtd_get_fact_prot_info(struct mtd_info *mtd, size_t len, size_t *retlen,
1664                            struct otp_info *buf)
1665 {
1666         if (!mtd->_get_fact_prot_info)
1667                 return -EOPNOTSUPP;
1668         if (!len)
1669                 return 0;
1670         return mtd->_get_fact_prot_info(mtd, len, retlen, buf);
1671 }
1672 EXPORT_SYMBOL_GPL(mtd_get_fact_prot_info);
1673 
1674 int mtd_read_fact_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
1675                            size_t *retlen, u_char *buf)
1676 {
1677         *retlen = 0;
1678         if (!mtd->_read_fact_prot_reg)
1679                 return -EOPNOTSUPP;
1680         if (!len)
1681                 return 0;
1682         return mtd->_read_fact_prot_reg(mtd, from, len, retlen, buf);
1683 }
1684 EXPORT_SYMBOL_GPL(mtd_read_fact_prot_reg);
1685 
1686 int mtd_get_user_prot_info(struct mtd_info *mtd, size_t len, size_t *retlen,
1687                            struct otp_info *buf)
1688 {
1689         if (!mtd->_get_user_prot_info)
1690                 return -EOPNOTSUPP;
1691         if (!len)
1692                 return 0;
1693         return mtd->_get_user_prot_info(mtd, len, retlen, buf);
1694 }
1695 EXPORT_SYMBOL_GPL(mtd_get_user_prot_info);
1696 
1697 int mtd_read_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
1698                            size_t *retlen, u_char *buf)
1699 {
1700         *retlen = 0;
1701         if (!mtd->_read_user_prot_reg)
1702                 return -EOPNOTSUPP;
1703         if (!len)
1704                 return 0;
1705         return mtd->_read_user_prot_reg(mtd, from, len, retlen, buf);
1706 }
1707 EXPORT_SYMBOL_GPL(mtd_read_user_prot_reg);
1708 
1709 int mtd_write_user_prot_reg(struct mtd_info *mtd, loff_t to, size_t len,
1710                             size_t *retlen, u_char *buf)
1711 {
1712         int ret;
1713 
1714         *retlen = 0;
1715         if (!mtd->_write_user_prot_reg)
1716                 return -EOPNOTSUPP;
1717         if (!len)
1718                 return 0;
1719         ret = mtd->_write_user_prot_reg(mtd, to, len, retlen, buf);
1720         if (ret)
1721                 return ret;
1722 
1723         /*
1724          * If no data could be written at all, we are out of memory and
1725          * must return -ENOSPC.
1726          */
1727         return (*retlen) ? 0 : -ENOSPC;
1728 }
1729 EXPORT_SYMBOL_GPL(mtd_write_user_prot_reg);
1730 
1731 int mtd_lock_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len)
1732 {
1733         if (!mtd->_lock_user_prot_reg)
1734                 return -EOPNOTSUPP;
1735         if (!len)
1736                 return 0;
1737         return mtd->_lock_user_prot_reg(mtd, from, len);
1738 }
1739 EXPORT_SYMBOL_GPL(mtd_lock_user_prot_reg);
1740 
1741 /* Chip-supported device locking */
1742 int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
1743 {
1744         if (!mtd->_lock)
1745                 return -EOPNOTSUPP;
1746         if (ofs < 0 || ofs >= mtd->size || len > mtd->size - ofs)
1747                 return -EINVAL;
1748         if (!len)
1749                 return 0;
1750         return mtd->_lock(mtd, ofs, len);
1751 }
1752 EXPORT_SYMBOL_GPL(mtd_lock);
1753 
1754 int mtd_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
1755 {
1756         if (!mtd->_unlock)
1757                 return -EOPNOTSUPP;
1758         if (ofs < 0 || ofs >= mtd->size || len > mtd->size - ofs)
1759                 return -EINVAL;
1760         if (!len)
1761                 return 0;
1762         return mtd->_unlock(mtd, ofs, len);
1763 }
1764 EXPORT_SYMBOL_GPL(mtd_unlock);
1765 
1766 int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
1767 {
1768         if (!mtd->_is_locked)
1769                 return -EOPNOTSUPP;
1770         if (ofs < 0 || ofs >= mtd->size || len > mtd->size - ofs)
1771                 return -EINVAL;
1772         if (!len)
1773                 return 0;
1774         return mtd->_is_locked(mtd, ofs, len);
1775 }
1776 EXPORT_SYMBOL_GPL(mtd_is_locked);
1777 
1778 int mtd_block_isreserved(struct mtd_info *mtd, loff_t ofs)
1779 {
1780         if (ofs < 0 || ofs >= mtd->size)
1781                 return -EINVAL;
1782         if (!mtd->_block_isreserved)
1783                 return 0;
1784         return mtd->_block_isreserved(mtd, ofs);
1785 }
1786 EXPORT_SYMBOL_GPL(mtd_block_isreserved);
1787 
1788 int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs)
1789 {
1790         if (ofs < 0 || ofs >= mtd->size)
1791                 return -EINVAL;
1792         if (!mtd->_block_isbad)
1793                 return 0;
1794         return mtd->_block_isbad(mtd, ofs);
1795 }
1796 EXPORT_SYMBOL_GPL(mtd_block_isbad);
1797 
1798 int mtd_block_markbad(struct mtd_info *mtd, loff_t ofs)
1799 {
1800         if (!mtd->_block_markbad)
1801                 return -EOPNOTSUPP;
1802         if (ofs < 0 || ofs >= mtd->size)
1803                 return -EINVAL;
1804         if (!(mtd->flags & MTD_WRITEABLE))
1805                 return -EROFS;
1806         return mtd->_block_markbad(mtd, ofs);
1807 }
1808 EXPORT_SYMBOL_GPL(mtd_block_markbad);
1809 
1810 /*
1811  * default_mtd_writev - the default writev method
1812  * @mtd: mtd device description object pointer
1813  * @vecs: the vectors to write
1814  * @count: count of vectors in @vecs
1815  * @to: the MTD device offset to write to
1816  * @retlen: on exit contains the count of bytes written to the MTD device.
1817  *
1818  * This function returns zero in case of success and a negative error code in
1819  * case of failure.
1820  */
1821 static int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
1822                               unsigned long count, loff_t to, size_t *retlen)
1823 {
1824         unsigned long i;
1825         size_t totlen = 0, thislen;
1826         int ret = 0;
1827 
1828         for (i = 0; i < count; i++) {
1829                 if (!vecs[i].iov_len)
1830                         continue;
1831                 ret = mtd_write(mtd, to, vecs[i].iov_len, &thislen,
1832                                 vecs[i].iov_base);
1833                 totlen += thislen;
1834                 if (ret || thislen != vecs[i].iov_len)
1835                         break;
1836                 to += vecs[i].iov_len;
1837         }
1838         *retlen = totlen;
1839         return ret;
1840 }
1841 
1842 /*
1843  * mtd_writev - the vector-based MTD write method
1844  * @mtd: mtd device description object pointer
1845  * @vecs: the vectors to write
1846  * @count: count of vectors in @vecs
1847  * @to: the MTD device offset to write to
1848  * @retlen: on exit contains the count of bytes written to the MTD device.
1849  *
1850  * This function returns zero in case of success and a negative error code in
1851  * case of failure.
1852  */
1853 int mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
1854                unsigned long count, loff_t to, size_t *retlen)
1855 {
1856         *retlen = 0;
1857         if (!(mtd->flags & MTD_WRITEABLE))
1858                 return -EROFS;
1859         if (!mtd->_writev)
1860                 return default_mtd_writev(mtd, vecs, count, to, retlen);
1861         return mtd->_writev(mtd, vecs, count, to, retlen);
1862 }
1863 EXPORT_SYMBOL_GPL(mtd_writev);
1864 
1865 /**
1866  * mtd_kmalloc_up_to - allocate a contiguous buffer up to the specified size
1867  * @mtd: mtd device description object pointer
1868  * @size: a pointer to the ideal or maximum size of the allocation, points
1869  *        to the actual allocation size on success.
1870  *
1871  * This routine attempts to allocate a contiguous kernel buffer up to
1872  * the specified size, backing off the size of the request exponentially
1873  * until the request succeeds or until the allocation size falls below
1874  * the system page size. This attempts to make sure it does not adversely
1875  * impact system performance, so when allocating more than one page, we
1876  * ask the memory allocator to avoid re-trying, swapping, writing back
1877  * or performing I/O.
1878  *
1879  * Note, this function also makes sure that the allocated buffer is aligned to
1880  * the MTD device's min. I/O unit, i.e. the "mtd->writesize" value.
1881  *
1882  * This is called, for example by mtd_{read,write} and jffs2_scan_medium,
1883  * to handle smaller (i.e. degraded) buffer allocations under low- or
1884  * fragmented-memory situations where such reduced allocations, from a
1885  * requested ideal, are allowed.
1886  *
1887  * Returns a pointer to the allocated buffer on success; otherwise, NULL.
1888  */
1889 void *mtd_kmalloc_up_to(const struct mtd_info *mtd, size_t *size)
1890 {
1891         gfp_t flags = __GFP_NOWARN | __GFP_DIRECT_RECLAIM | __GFP_NORETRY;
1892         size_t min_alloc = max_t(size_t, mtd->writesize, PAGE_SIZE);
1893         void *kbuf;
1894 
1895         *size = min_t(size_t, *size, KMALLOC_MAX_SIZE);
1896 
1897         while (*size > min_alloc) {
1898                 kbuf = kmalloc(*size, flags);
1899                 if (kbuf)
1900                         return kbuf;
1901 
1902                 *size >>= 1;
1903                 *size = ALIGN(*size, mtd->writesize);
1904         }
1905 
1906         /*
1907          * For the last resort allocation allow 'kmalloc()' to do all sorts of
1908          * things (write-back, dropping caches, etc) by using GFP_KERNEL.
1909          */
1910         return kmalloc(*size, GFP_KERNEL);
1911 }
1912 EXPORT_SYMBOL_GPL(mtd_kmalloc_up_to);
1913 
1914 #ifdef CONFIG_PROC_FS
1915 
1916 /*====================================================================*/
1917 /* Support for /proc/mtd */
1918 
1919 static int mtd_proc_show(struct seq_file *m, void *v)
1920 {
1921         struct mtd_info *mtd;
1922 
1923         seq_puts(m, "dev:    size   erasesize  name\n");
1924         mutex_lock(&mtd_table_mutex);
1925         mtd_for_each_device(mtd) {
1926                 seq_printf(m, "mtd%d: %8.8llx %8.8x \"%s\"\n",
1927                            mtd->index, (unsigned long long)mtd->size,
1928                            mtd->erasesize, mtd->name);
1929         }
1930         mutex_unlock(&mtd_table_mutex);
1931         return 0;
1932 }
1933 #endif /* CONFIG_PROC_FS */
1934 
1935 /*====================================================================*/
1936 /* Init code */
1937 
1938 static struct backing_dev_info * __init mtd_bdi_init(char *name)
1939 {
1940         struct backing_dev_info *bdi;
1941         int ret;
1942 
1943         bdi = bdi_alloc(GFP_KERNEL);
1944         if (!bdi)
1945                 return ERR_PTR(-ENOMEM);
1946 
1947         bdi->name = name;
1948         /*
1949          * We put '-0' suffix to the name to get the same name format as we
1950          * used to get. Since this is called only once, we get a unique name. 
1951          */
1952         ret = bdi_register(bdi, "%.28s-0", name);
1953         if (ret)
1954                 bdi_put(bdi);
1955 
1956         return ret ? ERR_PTR(ret) : bdi;
1957 }
1958 
1959 static struct proc_dir_entry *proc_mtd;
1960 
1961 static int __init init_mtd(void)
1962 {
1963         int ret;
1964 
1965         ret = class_register(&mtd_class);
1966         if (ret)
1967                 goto err_reg;
1968 
1969         mtd_bdi = mtd_bdi_init("mtd");
1970         if (IS_ERR(mtd_bdi)) {
1971                 ret = PTR_ERR(mtd_bdi);
1972                 goto err_bdi;
1973         }
1974 
1975         proc_mtd = proc_create_single("mtd", 0, NULL, mtd_proc_show);
1976 
1977         ret = init_mtdchar();
1978         if (ret)
1979                 goto out_procfs;
1980 
1981         dfs_dir_mtd = debugfs_create_dir("mtd", NULL);
1982 
1983         return 0;
1984 
1985 out_procfs:
1986         if (proc_mtd)
1987                 remove_proc_entry("mtd", NULL);
1988         bdi_put(mtd_bdi);
1989 err_bdi:
1990         class_unregister(&mtd_class);
1991 err_reg:
1992         pr_err("Error registering mtd class or bdi: %d\n", ret);
1993         return ret;
1994 }
1995 
1996 static void __exit cleanup_mtd(void)
1997 {
1998         debugfs_remove_recursive(dfs_dir_mtd);
1999         cleanup_mtdchar();
2000         if (proc_mtd)
2001                 remove_proc_entry("mtd", NULL);
2002         class_unregister(&mtd_class);
2003         bdi_put(mtd_bdi);
2004         idr_destroy(&mtd_idr);
2005 }
2006 
2007 module_init(init_mtd);
2008 module_exit(cleanup_mtd);
2009 
2010 MODULE_LICENSE("GPL");
2011 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
2012 MODULE_DESCRIPTION("Core MTD registration and access routines");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/mtd/mtdcore.c

DEFINITIONS
