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#include <linux/root_dev.h>
  32
  33#include <linux/mtd/mtd.h>
  34#include <linux/mtd/partitions.h>
  35
  36#include "mtdcore.h"
  37
  38struct backing_dev_info *mtd_bdi;
  39
  40#ifdef CONFIG_PM_SLEEP
  41
  42static int mtd_cls_suspend(struct device *dev)
  43{
  44	struct mtd_info *mtd = dev_get_drvdata(dev);
  45
  46	return mtd ? mtd_suspend(mtd) : 0;
  47}
  48
  49static int mtd_cls_resume(struct device *dev)
  50{
  51	struct mtd_info *mtd = dev_get_drvdata(dev);
  52
  53	if (mtd)
  54		mtd_resume(mtd);
  55	return 0;
  56}
  57
  58static SIMPLE_DEV_PM_OPS(mtd_cls_pm_ops, mtd_cls_suspend, mtd_cls_resume);
  59#define MTD_CLS_PM_OPS (&mtd_cls_pm_ops)
  60#else
  61#define MTD_CLS_PM_OPS NULL
  62#endif
  63
  64static struct class mtd_class = {
  65	.name = "mtd",
  66	.owner = THIS_MODULE,
  67	.pm = MTD_CLS_PM_OPS,
  68};
  69
  70static DEFINE_IDR(mtd_idr);
  71
  72/* These are exported solely for the purpose of mtd_blkdevs.c. You
  73   should not use them for _anything_ else */
  74DEFINE_MUTEX(mtd_table_mutex);
  75EXPORT_SYMBOL_GPL(mtd_table_mutex);
  76
  77struct mtd_info *__mtd_next_device(int i)
  78{
  79	return idr_get_next(&mtd_idr, &i);
  80}
  81EXPORT_SYMBOL_GPL(__mtd_next_device);
  82
  83static LIST_HEAD(mtd_notifiers);
  84
  85
  86#define MTD_DEVT(index) MKDEV(MTD_CHAR_MAJOR, (index)*2)
  87
  88/* REVISIT once MTD uses the driver model better, whoever allocates
  89 * the mtd_info will probably want to use the release() hook...
  90 */
  91static void mtd_release(struct device *dev)
  92{
  93	struct mtd_info *mtd = dev_get_drvdata(dev);
  94	dev_t index = MTD_DEVT(mtd->index);
  95
  96	/* remove /dev/mtdXro node */
  97	device_destroy(&mtd_class, index + 1);
  98}
  99
 100#define MTD_DEVICE_ATTR_RO(name) \
 101static DEVICE_ATTR(name, 0444, mtd_##name##_show, NULL)
 102
 103#define MTD_DEVICE_ATTR_RW(name) \
 104static DEVICE_ATTR(name, 0644, mtd_##name##_show, mtd_##name##_store)
 105
 106static ssize_t mtd_type_show(struct device *dev,
 107		struct device_attribute *attr, char *buf)
 108{
 109	struct mtd_info *mtd = dev_get_drvdata(dev);
 110	char *type;
 111
 112	switch (mtd->type) {
 113	case MTD_ABSENT:
 114		type = "absent";
 115		break;
 116	case MTD_RAM:
 117		type = "ram";
 118		break;
 119	case MTD_ROM:
 120		type = "rom";
 121		break;
 122	case MTD_NORFLASH:
 123		type = "nor";
 124		break;
 125	case MTD_NANDFLASH:
 126		type = "nand";
 127		break;
 128	case MTD_DATAFLASH:
 129		type = "dataflash";
 130		break;
 131	case MTD_UBIVOLUME:
 132		type = "ubi";
 133		break;
 134	case MTD_MLCNANDFLASH:
 135		type = "mlc-nand";
 136		break;
 137	default:
 138		type = "unknown";
 139	}
 140
 141	return sysfs_emit(buf, "%s\n", type);
 142}
 143MTD_DEVICE_ATTR_RO(type);
 144
 145static ssize_t mtd_flags_show(struct device *dev,
 146		struct device_attribute *attr, char *buf)
 147{
 148	struct mtd_info *mtd = dev_get_drvdata(dev);
 149
 150	return sysfs_emit(buf, "0x%lx\n", (unsigned long)mtd->flags);
 151}
 152MTD_DEVICE_ATTR_RO(flags);
 153
 154static ssize_t mtd_size_show(struct device *dev,
 155		struct device_attribute *attr, char *buf)
 156{
 157	struct mtd_info *mtd = dev_get_drvdata(dev);
 158
 159	return sysfs_emit(buf, "%llu\n", (unsigned long long)mtd->size);
 160}
 161MTD_DEVICE_ATTR_RO(size);
 162
 163static ssize_t mtd_erasesize_show(struct device *dev,
 164		struct device_attribute *attr, char *buf)
 165{
 166	struct mtd_info *mtd = dev_get_drvdata(dev);
 167
 168	return sysfs_emit(buf, "%lu\n", (unsigned long)mtd->erasesize);
 169}
 170MTD_DEVICE_ATTR_RO(erasesize);
 171
 172static ssize_t mtd_writesize_show(struct device *dev,
 173		struct device_attribute *attr, char *buf)
 174{
 175	struct mtd_info *mtd = dev_get_drvdata(dev);
 176
 177	return sysfs_emit(buf, "%lu\n", (unsigned long)mtd->writesize);
 178}
 179MTD_DEVICE_ATTR_RO(writesize);
 180
 181static ssize_t mtd_subpagesize_show(struct device *dev,
 182		struct device_attribute *attr, char *buf)
 183{
 184	struct mtd_info *mtd = dev_get_drvdata(dev);
 185	unsigned int subpagesize = mtd->writesize >> mtd->subpage_sft;
 186
 187	return sysfs_emit(buf, "%u\n", subpagesize);
 188}
 189MTD_DEVICE_ATTR_RO(subpagesize);
 190
 191static ssize_t mtd_oobsize_show(struct device *dev,
 192		struct device_attribute *attr, char *buf)
 193{
 194	struct mtd_info *mtd = dev_get_drvdata(dev);
 195
 196	return sysfs_emit(buf, "%lu\n", (unsigned long)mtd->oobsize);
 197}
 198MTD_DEVICE_ATTR_RO(oobsize);
 199
 200static ssize_t mtd_oobavail_show(struct device *dev,
 201				 struct device_attribute *attr, char *buf)
 202{
 203	struct mtd_info *mtd = dev_get_drvdata(dev);
 204
 205	return sysfs_emit(buf, "%u\n", mtd->oobavail);
 206}
 207MTD_DEVICE_ATTR_RO(oobavail);
 208
 209static ssize_t mtd_numeraseregions_show(struct device *dev,
 210		struct device_attribute *attr, char *buf)
 211{
 212	struct mtd_info *mtd = dev_get_drvdata(dev);
 213
 214	return sysfs_emit(buf, "%u\n", mtd->numeraseregions);
 215}
 216MTD_DEVICE_ATTR_RO(numeraseregions);
 217
 218static ssize_t mtd_name_show(struct device *dev,
 219		struct device_attribute *attr, char *buf)
 220{
 221	struct mtd_info *mtd = dev_get_drvdata(dev);
 222
 223	return sysfs_emit(buf, "%s\n", mtd->name);
 224}
 225MTD_DEVICE_ATTR_RO(name);
 226
 227static ssize_t mtd_ecc_strength_show(struct device *dev,
 228				     struct device_attribute *attr, char *buf)
 229{
 230	struct mtd_info *mtd = dev_get_drvdata(dev);
 231
 232	return sysfs_emit(buf, "%u\n", mtd->ecc_strength);
 233}
 234MTD_DEVICE_ATTR_RO(ecc_strength);
 235
 236static ssize_t mtd_bitflip_threshold_show(struct device *dev,
 237					  struct device_attribute *attr,
 238					  char *buf)
 239{
 240	struct mtd_info *mtd = dev_get_drvdata(dev);
 241
 242	return sysfs_emit(buf, "%u\n", mtd->bitflip_threshold);
 243}
 244
 245static ssize_t mtd_bitflip_threshold_store(struct device *dev,
 246					   struct device_attribute *attr,
 247					   const char *buf, size_t count)
 248{
 249	struct mtd_info *mtd = dev_get_drvdata(dev);
 250	unsigned int bitflip_threshold;
 251	int retval;
 252
 253	retval = kstrtouint(buf, 0, &bitflip_threshold);
 254	if (retval)
 255		return retval;
 256
 257	mtd->bitflip_threshold = bitflip_threshold;
 258	return count;
 259}
 260MTD_DEVICE_ATTR_RW(bitflip_threshold);
 261
 262static ssize_t mtd_ecc_step_size_show(struct device *dev,
 263		struct device_attribute *attr, char *buf)
 264{
 265	struct mtd_info *mtd = dev_get_drvdata(dev);
 266
 267	return sysfs_emit(buf, "%u\n", mtd->ecc_step_size);
 268
 269}
 270MTD_DEVICE_ATTR_RO(ecc_step_size);
 271
 272static ssize_t mtd_corrected_bits_show(struct device *dev,
 273		struct device_attribute *attr, char *buf)
 274{
 275	struct mtd_info *mtd = dev_get_drvdata(dev);
 276	struct mtd_ecc_stats *ecc_stats = &mtd->ecc_stats;
 277
 278	return sysfs_emit(buf, "%u\n", ecc_stats->corrected);
 279}
 280MTD_DEVICE_ATTR_RO(corrected_bits);	/* ecc stats corrected */
 281
 282static ssize_t mtd_ecc_failures_show(struct device *dev,
 283		struct device_attribute *attr, char *buf)
 284{
 285	struct mtd_info *mtd = dev_get_drvdata(dev);
 286	struct mtd_ecc_stats *ecc_stats = &mtd->ecc_stats;
 287
 288	return sysfs_emit(buf, "%u\n", ecc_stats->failed);
 289}
 290MTD_DEVICE_ATTR_RO(ecc_failures);	/* ecc stats errors */
 291
 292static ssize_t mtd_bad_blocks_show(struct device *dev,
 293		struct device_attribute *attr, char *buf)
 294{
 295	struct mtd_info *mtd = dev_get_drvdata(dev);
 296	struct mtd_ecc_stats *ecc_stats = &mtd->ecc_stats;
 297
 298	return sysfs_emit(buf, "%u\n", ecc_stats->badblocks);
 299}
 300MTD_DEVICE_ATTR_RO(bad_blocks);
 301
 302static ssize_t mtd_bbt_blocks_show(struct device *dev,
 303		struct device_attribute *attr, char *buf)
 304{
 305	struct mtd_info *mtd = dev_get_drvdata(dev);
 306	struct mtd_ecc_stats *ecc_stats = &mtd->ecc_stats;
 307
 308	return sysfs_emit(buf, "%u\n", ecc_stats->bbtblocks);
 309}
 310MTD_DEVICE_ATTR_RO(bbt_blocks);
 311
 312static struct attribute *mtd_attrs[] = {
 313	&dev_attr_type.attr,
 314	&dev_attr_flags.attr,
 315	&dev_attr_size.attr,
 316	&dev_attr_erasesize.attr,
 317	&dev_attr_writesize.attr,
 318	&dev_attr_subpagesize.attr,
 319	&dev_attr_oobsize.attr,
 320	&dev_attr_oobavail.attr,
 321	&dev_attr_numeraseregions.attr,
 322	&dev_attr_name.attr,
 323	&dev_attr_ecc_strength.attr,
 324	&dev_attr_ecc_step_size.attr,
 325	&dev_attr_corrected_bits.attr,
 326	&dev_attr_ecc_failures.attr,
 327	&dev_attr_bad_blocks.attr,
 328	&dev_attr_bbt_blocks.attr,
 329	&dev_attr_bitflip_threshold.attr,
 330	NULL,
 331};
 332ATTRIBUTE_GROUPS(mtd);
 333
 334static const struct device_type mtd_devtype = {
 335	.name		= "mtd",
 336	.groups		= mtd_groups,
 337	.release	= mtd_release,
 338};
 339
 340static bool mtd_expert_analysis_mode;
 
 
 
 
 
 
 
 
 
 341
 342#ifdef CONFIG_DEBUG_FS
 343bool mtd_check_expert_analysis_mode(void)
 344{
 345	const char *mtd_expert_analysis_warning =
 346		"Bad block checks have been entirely disabled.\n"
 347		"This is only reserved for post-mortem forensics and debug purposes.\n"
 348		"Never enable this mode if you do not know what you are doing!\n";
 349
 350	return WARN_ONCE(mtd_expert_analysis_mode, mtd_expert_analysis_warning);
 
 
 351}
 352EXPORT_SYMBOL_GPL(mtd_check_expert_analysis_mode);
 353#endif
 354
 355static struct dentry *dfs_dir_mtd;
 356
 357static void mtd_debugfs_populate(struct mtd_info *mtd)
 358{
 
 359	struct device *dev = &mtd->dev;
 
 360
 361	if (IS_ERR_OR_NULL(dfs_dir_mtd))
 362		return;
 363
 364	mtd->dbg.dfs_dir = debugfs_create_dir(dev_name(dev), dfs_dir_mtd);
 
 
 
 
 
 
 
 
 
 365}
 366
 367#ifndef CONFIG_MMU
 368unsigned mtd_mmap_capabilities(struct mtd_info *mtd)
 369{
 370	switch (mtd->type) {
 371	case MTD_RAM:
 372		return NOMMU_MAP_COPY | NOMMU_MAP_DIRECT | NOMMU_MAP_EXEC |
 373			NOMMU_MAP_READ | NOMMU_MAP_WRITE;
 374	case MTD_ROM:
 375		return NOMMU_MAP_COPY | NOMMU_MAP_DIRECT | NOMMU_MAP_EXEC |
 376			NOMMU_MAP_READ;
 377	default:
 378		return NOMMU_MAP_COPY;
 379	}
 380}
 381EXPORT_SYMBOL_GPL(mtd_mmap_capabilities);
 382#endif
 383
 384static int mtd_reboot_notifier(struct notifier_block *n, unsigned long state,
 385			       void *cmd)
 386{
 387	struct mtd_info *mtd;
 388
 389	mtd = container_of(n, struct mtd_info, reboot_notifier);
 390	mtd->_reboot(mtd);
 391
 392	return NOTIFY_DONE;
 393}
 394
 395/**
 396 * mtd_wunit_to_pairing_info - get pairing information of a wunit
 397 * @mtd: pointer to new MTD device info structure
 398 * @wunit: write unit we are interested in
 399 * @info: returned pairing information
 400 *
 401 * Retrieve pairing information associated to the wunit.
 402 * This is mainly useful when dealing with MLC/TLC NANDs where pages can be
 403 * paired together, and where programming a page may influence the page it is
 404 * paired with.
 405 * The notion of page is replaced by the term wunit (write-unit) to stay
 406 * consistent with the ->writesize field.
 407 *
 408 * The @wunit argument can be extracted from an absolute offset using
 409 * mtd_offset_to_wunit(). @info is filled with the pairing information attached
 410 * to @wunit.
 411 *
 412 * From the pairing info the MTD user can find all the wunits paired with
 413 * @wunit using the following loop:
 414 *
 415 * for (i = 0; i < mtd_pairing_groups(mtd); i++) {
 416 *	info.pair = i;
 417 *	mtd_pairing_info_to_wunit(mtd, &info);
 418 *	...
 419 * }
 420 */
 421int mtd_wunit_to_pairing_info(struct mtd_info *mtd, int wunit,
 422			      struct mtd_pairing_info *info)
 423{
 424	struct mtd_info *master = mtd_get_master(mtd);
 425	int npairs = mtd_wunit_per_eb(master) / mtd_pairing_groups(master);
 426
 427	if (wunit < 0 || wunit >= npairs)
 428		return -EINVAL;
 429
 430	if (master->pairing && master->pairing->get_info)
 431		return master->pairing->get_info(master, wunit, info);
 432
 433	info->group = 0;
 434	info->pair = wunit;
 435
 436	return 0;
 437}
 438EXPORT_SYMBOL_GPL(mtd_wunit_to_pairing_info);
 439
 440/**
 441 * mtd_pairing_info_to_wunit - get wunit from pairing information
 442 * @mtd: pointer to new MTD device info structure
 443 * @info: pairing information struct
 444 *
 445 * Returns a positive number representing the wunit associated to the info
 446 * struct, or a negative error code.
 447 *
 448 * This is the reverse of mtd_wunit_to_pairing_info(), and can help one to
 449 * iterate over all wunits of a given pair (see mtd_wunit_to_pairing_info()
 450 * doc).
 451 *
 452 * It can also be used to only program the first page of each pair (i.e.
 453 * page attached to group 0), which allows one to use an MLC NAND in
 454 * software-emulated SLC mode:
 455 *
 456 * info.group = 0;
 457 * npairs = mtd_wunit_per_eb(mtd) / mtd_pairing_groups(mtd);
 458 * for (info.pair = 0; info.pair < npairs; info.pair++) {
 459 *	wunit = mtd_pairing_info_to_wunit(mtd, &info);
 460 *	mtd_write(mtd, mtd_wunit_to_offset(mtd, blkoffs, wunit),
 461 *		  mtd->writesize, &retlen, buf + (i * mtd->writesize));
 462 * }
 463 */
 464int mtd_pairing_info_to_wunit(struct mtd_info *mtd,
 465			      const struct mtd_pairing_info *info)
 466{
 467	struct mtd_info *master = mtd_get_master(mtd);
 468	int ngroups = mtd_pairing_groups(master);
 469	int npairs = mtd_wunit_per_eb(master) / ngroups;
 470
 471	if (!info || info->pair < 0 || info->pair >= npairs ||
 472	    info->group < 0 || info->group >= ngroups)
 473		return -EINVAL;
 474
 475	if (master->pairing && master->pairing->get_wunit)
 476		return mtd->pairing->get_wunit(master, info);
 477
 478	return info->pair;
 479}
 480EXPORT_SYMBOL_GPL(mtd_pairing_info_to_wunit);
 481
 482/**
 483 * mtd_pairing_groups - get the number of pairing groups
 484 * @mtd: pointer to new MTD device info structure
 485 *
 486 * Returns the number of pairing groups.
 487 *
 488 * This number is usually equal to the number of bits exposed by a single
 489 * cell, and can be used in conjunction with mtd_pairing_info_to_wunit()
 490 * to iterate over all pages of a given pair.
 491 */
 492int mtd_pairing_groups(struct mtd_info *mtd)
 493{
 494	struct mtd_info *master = mtd_get_master(mtd);
 495
 496	if (!master->pairing || !master->pairing->ngroups)
 497		return 1;
 498
 499	return master->pairing->ngroups;
 500}
 501EXPORT_SYMBOL_GPL(mtd_pairing_groups);
 502
 503static int mtd_nvmem_reg_read(void *priv, unsigned int offset,
 504			      void *val, size_t bytes)
 505{
 506	struct mtd_info *mtd = priv;
 507	size_t retlen;
 508	int err;
 509
 510	err = mtd_read(mtd, offset, bytes, &retlen, val);
 511	if (err && err != -EUCLEAN)
 512		return err;
 513
 514	return retlen == bytes ? 0 : -EIO;
 515}
 516
 517static int mtd_nvmem_add(struct mtd_info *mtd)
 518{
 519	struct device_node *node = mtd_get_of_node(mtd);
 520	struct nvmem_config config = {};
 521
 522	config.id = -1;
 523	config.dev = &mtd->dev;
 524	config.name = dev_name(&mtd->dev);
 525	config.owner = THIS_MODULE;
 526	config.reg_read = mtd_nvmem_reg_read;
 527	config.size = mtd->size;
 528	config.word_size = 1;
 529	config.stride = 1;
 530	config.read_only = true;
 531	config.root_only = true;
 532	config.ignore_wp = true;
 533	config.no_of_node = !of_device_is_compatible(node, "nvmem-cells");
 534	config.priv = mtd;
 535
 536	mtd->nvmem = nvmem_register(&config);
 537	if (IS_ERR(mtd->nvmem)) {
 538		/* Just ignore if there is no NVMEM support in the kernel */
 539		if (PTR_ERR(mtd->nvmem) == -EOPNOTSUPP) {
 540			mtd->nvmem = NULL;
 541		} else {
 542			dev_err(&mtd->dev, "Failed to register NVMEM device\n");
 543			return PTR_ERR(mtd->nvmem);
 544		}
 545	}
 546
 547	return 0;
 548}
 549
 550static void mtd_check_of_node(struct mtd_info *mtd)
 551{
 552	struct device_node *partitions, *parent_dn, *mtd_dn = NULL;
 553	const char *pname, *prefix = "partition-";
 554	int plen, mtd_name_len, offset, prefix_len;
 555
 556	/* Check if MTD already has a device node */
 557	if (mtd_get_of_node(mtd))
 558		return;
 559
 560	if (!mtd_is_partition(mtd))
 561		return;
 562
 563	parent_dn = of_node_get(mtd_get_of_node(mtd->parent));
 564	if (!parent_dn)
 565		return;
 566
 567	if (mtd_is_partition(mtd->parent))
 568		partitions = of_node_get(parent_dn);
 569	else
 570		partitions = of_get_child_by_name(parent_dn, "partitions");
 571	if (!partitions)
 572		goto exit_parent;
 573
 574	prefix_len = strlen(prefix);
 575	mtd_name_len = strlen(mtd->name);
 576
 577	/* Search if a partition is defined with the same name */
 578	for_each_child_of_node(partitions, mtd_dn) {
 579		/* Skip partition with no/wrong prefix */
 580		if (!of_node_name_prefix(mtd_dn, prefix))
 581			continue;
 582
 583		/* Label have priority. Check that first */
 584		if (!of_property_read_string(mtd_dn, "label", &pname)) {
 585			offset = 0;
 586		} else {
 587			pname = mtd_dn->name;
 588			offset = prefix_len;
 589		}
 590
 591		plen = strlen(pname) - offset;
 592		if (plen == mtd_name_len &&
 593		    !strncmp(mtd->name, pname + offset, plen)) {
 594			mtd_set_of_node(mtd, mtd_dn);
 595			break;
 596		}
 597	}
 598
 599	of_node_put(partitions);
 600exit_parent:
 601	of_node_put(parent_dn);
 602}
 603
 604/**
 605 *	add_mtd_device - register an MTD device
 606 *	@mtd: pointer to new MTD device info structure
 607 *
 608 *	Add a device to the list of MTD devices present in the system, and
 609 *	notify each currently active MTD 'user' of its arrival. Returns
 610 *	zero on success or non-zero on failure.
 611 */
 612
 613int add_mtd_device(struct mtd_info *mtd)
 614{
 615	struct device_node *np = mtd_get_of_node(mtd);
 616	struct mtd_info *master = mtd_get_master(mtd);
 617	struct mtd_notifier *not;
 618	int i, error, ofidx;
 619
 620	/*
 621	 * May occur, for instance, on buggy drivers which call
 622	 * mtd_device_parse_register() multiple times on the same master MTD,
 623	 * especially with CONFIG_MTD_PARTITIONED_MASTER=y.
 624	 */
 625	if (WARN_ONCE(mtd->dev.type, "MTD already registered\n"))
 626		return -EEXIST;
 627
 628	BUG_ON(mtd->writesize == 0);
 629
 630	/*
 631	 * MTD drivers should implement ->_{write,read}() or
 632	 * ->_{write,read}_oob(), but not both.
 633	 */
 634	if (WARN_ON((mtd->_write && mtd->_write_oob) ||
 635		    (mtd->_read && mtd->_read_oob)))
 636		return -EINVAL;
 637
 638	if (WARN_ON((!mtd->erasesize || !master->_erase) &&
 639		    !(mtd->flags & MTD_NO_ERASE)))
 640		return -EINVAL;
 641
 642	/*
 643	 * MTD_SLC_ON_MLC_EMULATION can only be set on partitions, when the
 644	 * master is an MLC NAND and has a proper pairing scheme defined.
 645	 * We also reject masters that implement ->_writev() for now, because
 646	 * NAND controller drivers don't implement this hook, and adding the
 647	 * SLC -> MLC address/length conversion to this path is useless if we
 648	 * don't have a user.
 649	 */
 650	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION &&
 651	    (!mtd_is_partition(mtd) || master->type != MTD_MLCNANDFLASH ||
 652	     !master->pairing || master->_writev))
 653		return -EINVAL;
 654
 655	mutex_lock(&mtd_table_mutex);
 656
 657	ofidx = -1;
 658	if (np)
 659		ofidx = of_alias_get_id(np, "mtd");
 660	if (ofidx >= 0)
 661		i = idr_alloc(&mtd_idr, mtd, ofidx, ofidx + 1, GFP_KERNEL);
 662	else
 663		i = idr_alloc(&mtd_idr, mtd, 0, 0, GFP_KERNEL);
 664	if (i < 0) {
 665		error = i;
 666		goto fail_locked;
 667	}
 668
 669	mtd->index = i;
 670	mtd->usecount = 0;
 671
 672	/* default value if not set by driver */
 673	if (mtd->bitflip_threshold == 0)
 674		mtd->bitflip_threshold = mtd->ecc_strength;
 675
 676	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) {
 677		int ngroups = mtd_pairing_groups(master);
 678
 679		mtd->erasesize /= ngroups;
 680		mtd->size = (u64)mtd_div_by_eb(mtd->size, master) *
 681			    mtd->erasesize;
 682	}
 683
 684	if (is_power_of_2(mtd->erasesize))
 685		mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
 686	else
 687		mtd->erasesize_shift = 0;
 688
 689	if (is_power_of_2(mtd->writesize))
 690		mtd->writesize_shift = ffs(mtd->writesize) - 1;
 691	else
 692		mtd->writesize_shift = 0;
 693
 694	mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
 695	mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;
 696
 697	/* Some chips always power up locked. Unlock them now */
 698	if ((mtd->flags & MTD_WRITEABLE) && (mtd->flags & MTD_POWERUP_LOCK)) {
 699		error = mtd_unlock(mtd, 0, mtd->size);
 700		if (error && error != -EOPNOTSUPP)
 701			printk(KERN_WARNING
 702			       "%s: unlock failed, writes may not work\n",
 703			       mtd->name);
 704		/* Ignore unlock failures? */
 705		error = 0;
 706	}
 707
 708	/* Caller should have set dev.parent to match the
 709	 * physical device, if appropriate.
 710	 */
 711	mtd->dev.type = &mtd_devtype;
 712	mtd->dev.class = &mtd_class;
 713	mtd->dev.devt = MTD_DEVT(i);
 714	dev_set_name(&mtd->dev, "mtd%d", i);
 715	dev_set_drvdata(&mtd->dev, mtd);
 716	mtd_check_of_node(mtd);
 717	of_node_get(mtd_get_of_node(mtd));
 718	error = device_register(&mtd->dev);
 719	if (error) {
 720		put_device(&mtd->dev);
 721		goto fail_added;
 722	}
 723
 724	/* Add the nvmem provider */
 725	error = mtd_nvmem_add(mtd);
 726	if (error)
 727		goto fail_nvmem_add;
 728
 729	mtd_debugfs_populate(mtd);
 730
 731	device_create(&mtd_class, mtd->dev.parent, MTD_DEVT(i) + 1, NULL,
 732		      "mtd%dro", i);
 733
 734	pr_debug("mtd: Giving out device %d to %s\n", i, mtd->name);
 735	/* No need to get a refcount on the module containing
 736	   the notifier, since we hold the mtd_table_mutex */
 737	list_for_each_entry(not, &mtd_notifiers, list)
 738		not->add(mtd);
 739
 740	mutex_unlock(&mtd_table_mutex);
 741
 742	if (of_find_property(mtd_get_of_node(mtd), "linux,rootfs", NULL)) {
 743		if (IS_BUILTIN(CONFIG_MTD)) {
 744			pr_info("mtd: setting mtd%d (%s) as root device\n", mtd->index, mtd->name);
 745			ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
 746		} else {
 747			pr_warn("mtd: can't set mtd%d (%s) as root device - mtd must be builtin\n",
 748				mtd->index, mtd->name);
 749		}
 750	}
 751
 752	/* We _know_ we aren't being removed, because
 753	   our caller is still holding us here. So none
 754	   of this try_ nonsense, and no bitching about it
 755	   either. :) */
 756	__module_get(THIS_MODULE);
 757	return 0;
 758
 759fail_nvmem_add:
 760	device_unregister(&mtd->dev);
 761fail_added:
 762	of_node_put(mtd_get_of_node(mtd));
 763	idr_remove(&mtd_idr, i);
 764fail_locked:
 765	mutex_unlock(&mtd_table_mutex);
 766	return error;
 767}
 768
 769/**
 770 *	del_mtd_device - unregister an MTD device
 771 *	@mtd: pointer to MTD device info structure
 772 *
 773 *	Remove a device from the list of MTD devices present in the system,
 774 *	and notify each currently active MTD 'user' of its departure.
 775 *	Returns zero on success or 1 on failure, which currently will happen
 776 *	if the requested device does not appear to be present in the list.
 777 */
 778
 779int del_mtd_device(struct mtd_info *mtd)
 780{
 781	int ret;
 782	struct mtd_notifier *not;
 783	struct device_node *mtd_of_node;
 784
 785	mutex_lock(&mtd_table_mutex);
 786
 
 
 787	if (idr_find(&mtd_idr, mtd->index) != mtd) {
 788		ret = -ENODEV;
 789		goto out_error;
 790	}
 791
 792	/* No need to get a refcount on the module containing
 793		the notifier, since we hold the mtd_table_mutex */
 794	list_for_each_entry(not, &mtd_notifiers, list)
 795		not->remove(mtd);
 796
 797	if (mtd->usecount) {
 798		printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
 799		       mtd->index, mtd->name, mtd->usecount);
 800		ret = -EBUSY;
 801	} else {
 802		mtd_of_node = mtd_get_of_node(mtd);
 803		debugfs_remove_recursive(mtd->dbg.dfs_dir);
 804
 805		/* Try to remove the NVMEM provider */
 806		nvmem_unregister(mtd->nvmem);
 
 807
 808		device_unregister(&mtd->dev);
 809
 810		/* Clear dev so mtd can be safely re-registered later if desired */
 811		memset(&mtd->dev, 0, sizeof(mtd->dev));
 812
 813		idr_remove(&mtd_idr, mtd->index);
 814		of_node_put(mtd_of_node);
 815
 816		module_put(THIS_MODULE);
 817		ret = 0;
 818	}
 819
 820out_error:
 821	mutex_unlock(&mtd_table_mutex);
 822	return ret;
 823}
 824
 825/*
 826 * Set a few defaults based on the parent devices, if not provided by the
 827 * driver
 828 */
 829static void mtd_set_dev_defaults(struct mtd_info *mtd)
 830{
 831	if (mtd->dev.parent) {
 832		if (!mtd->owner && mtd->dev.parent->driver)
 833			mtd->owner = mtd->dev.parent->driver->owner;
 834		if (!mtd->name)
 835			mtd->name = dev_name(mtd->dev.parent);
 836	} else {
 837		pr_debug("mtd device won't show a device symlink in sysfs\n");
 838	}
 839
 840	INIT_LIST_HEAD(&mtd->partitions);
 841	mutex_init(&mtd->master.partitions_lock);
 842	mutex_init(&mtd->master.chrdev_lock);
 843}
 844
 845static ssize_t mtd_otp_size(struct mtd_info *mtd, bool is_user)
 846{
 847	struct otp_info *info;
 848	ssize_t size = 0;
 849	unsigned int i;
 850	size_t retlen;
 851	int ret;
 852
 853	info = kmalloc(PAGE_SIZE, GFP_KERNEL);
 854	if (!info)
 855		return -ENOMEM;
 856
 857	if (is_user)
 858		ret = mtd_get_user_prot_info(mtd, PAGE_SIZE, &retlen, info);
 859	else
 860		ret = mtd_get_fact_prot_info(mtd, PAGE_SIZE, &retlen, info);
 861	if (ret)
 862		goto err;
 863
 864	for (i = 0; i < retlen / sizeof(*info); i++)
 865		size += info[i].length;
 866
 867	kfree(info);
 868	return size;
 869
 870err:
 871	kfree(info);
 872
 873	/* ENODATA means there is no OTP region. */
 874	return ret == -ENODATA ? 0 : ret;
 875}
 876
 877static struct nvmem_device *mtd_otp_nvmem_register(struct mtd_info *mtd,
 878						   const char *compatible,
 879						   int size,
 880						   nvmem_reg_read_t reg_read)
 881{
 882	struct nvmem_device *nvmem = NULL;
 883	struct nvmem_config config = {};
 884	struct device_node *np;
 885
 886	/* DT binding is optional */
 887	np = of_get_compatible_child(mtd->dev.of_node, compatible);
 888
 889	/* OTP nvmem will be registered on the physical device */
 890	config.dev = mtd->dev.parent;
 891	config.name = kasprintf(GFP_KERNEL, "%s-%s", dev_name(&mtd->dev), compatible);
 
 892	config.id = NVMEM_DEVID_NONE;
 893	config.owner = THIS_MODULE;
 894	config.type = NVMEM_TYPE_OTP;
 895	config.root_only = true;
 896	config.ignore_wp = true;
 897	config.reg_read = reg_read;
 898	config.size = size;
 899	config.of_node = np;
 900	config.priv = mtd;
 901
 902	nvmem = nvmem_register(&config);
 903	/* Just ignore if there is no NVMEM support in the kernel */
 904	if (IS_ERR(nvmem) && PTR_ERR(nvmem) == -EOPNOTSUPP)
 905		nvmem = NULL;
 906
 907	of_node_put(np);
 908	kfree(config.name);
 909
 910	return nvmem;
 911}
 912
 913static int mtd_nvmem_user_otp_reg_read(void *priv, unsigned int offset,
 914				       void *val, size_t bytes)
 915{
 916	struct mtd_info *mtd = priv;
 917	size_t retlen;
 918	int ret;
 919
 920	ret = mtd_read_user_prot_reg(mtd, offset, bytes, &retlen, val);
 921	if (ret)
 922		return ret;
 923
 924	return retlen == bytes ? 0 : -EIO;
 925}
 926
 927static int mtd_nvmem_fact_otp_reg_read(void *priv, unsigned int offset,
 928				       void *val, size_t bytes)
 929{
 930	struct mtd_info *mtd = priv;
 931	size_t retlen;
 932	int ret;
 933
 934	ret = mtd_read_fact_prot_reg(mtd, offset, bytes, &retlen, val);
 935	if (ret)
 936		return ret;
 937
 938	return retlen == bytes ? 0 : -EIO;
 939}
 940
 941static int mtd_otp_nvmem_add(struct mtd_info *mtd)
 942{
 943	struct nvmem_device *nvmem;
 944	ssize_t size;
 945	int err;
 946
 947	if (mtd->_get_user_prot_info && mtd->_read_user_prot_reg) {
 948		size = mtd_otp_size(mtd, true);
 949		if (size < 0)
 950			return size;
 951
 952		if (size > 0) {
 953			nvmem = mtd_otp_nvmem_register(mtd, "user-otp", size,
 954						       mtd_nvmem_user_otp_reg_read);
 955			if (IS_ERR(nvmem)) {
 956				dev_err(&mtd->dev, "Failed to register OTP NVMEM device\n");
 957				return PTR_ERR(nvmem);
 958			}
 959			mtd->otp_user_nvmem = nvmem;
 960		}
 961	}
 962
 963	if (mtd->_get_fact_prot_info && mtd->_read_fact_prot_reg) {
 964		size = mtd_otp_size(mtd, false);
 965		if (size < 0) {
 966			err = size;
 967			goto err;
 968		}
 969
 970		if (size > 0) {
 971			nvmem = mtd_otp_nvmem_register(mtd, "factory-otp", size,
 972						       mtd_nvmem_fact_otp_reg_read);
 973			if (IS_ERR(nvmem)) {
 974				dev_err(&mtd->dev, "Failed to register OTP NVMEM device\n");
 975				err = PTR_ERR(nvmem);
 976				goto err;
 977			}
 978			mtd->otp_factory_nvmem = nvmem;
 979		}
 980	}
 981
 982	return 0;
 983
 984err:
 985	nvmem_unregister(mtd->otp_user_nvmem);
 
 986	return err;
 987}
 988
 989/**
 990 * mtd_device_parse_register - parse partitions and register an MTD device.
 991 *
 992 * @mtd: the MTD device to register
 993 * @types: the list of MTD partition probes to try, see
 994 *         'parse_mtd_partitions()' for more information
 995 * @parser_data: MTD partition parser-specific data
 996 * @parts: fallback partition information to register, if parsing fails;
 997 *         only valid if %nr_parts > %0
 998 * @nr_parts: the number of partitions in parts, if zero then the full
 999 *            MTD device is registered if no partition info is found
1000 *
1001 * This function aggregates MTD partitions parsing (done by
1002 * 'parse_mtd_partitions()') and MTD device and partitions registering. It
1003 * basically follows the most common pattern found in many MTD drivers:
1004 *
1005 * * If the MTD_PARTITIONED_MASTER option is set, then the device as a whole is
1006 *   registered first.
1007 * * Then It tries to probe partitions on MTD device @mtd using parsers
1008 *   specified in @types (if @types is %NULL, then the default list of parsers
1009 *   is used, see 'parse_mtd_partitions()' for more information). If none are
1010 *   found this functions tries to fallback to information specified in
1011 *   @parts/@nr_parts.
1012 * * If no partitions were found this function just registers the MTD device
1013 *   @mtd and exits.
1014 *
1015 * Returns zero in case of success and a negative error code in case of failure.
1016 */
1017int mtd_device_parse_register(struct mtd_info *mtd, const char * const *types,
1018			      struct mtd_part_parser_data *parser_data,
1019			      const struct mtd_partition *parts,
1020			      int nr_parts)
1021{
1022	int ret;
1023
1024	mtd_set_dev_defaults(mtd);
1025
1026	if (IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER)) {
1027		ret = add_mtd_device(mtd);
1028		if (ret)
1029			return ret;
1030	}
1031
1032	/* Prefer parsed partitions over driver-provided fallback */
1033	ret = parse_mtd_partitions(mtd, types, parser_data);
1034	if (ret == -EPROBE_DEFER)
1035		goto out;
1036
1037	if (ret > 0)
1038		ret = 0;
1039	else if (nr_parts)
1040		ret = add_mtd_partitions(mtd, parts, nr_parts);
1041	else if (!device_is_registered(&mtd->dev))
1042		ret = add_mtd_device(mtd);
1043	else
1044		ret = 0;
1045
1046	if (ret)
1047		goto out;
1048
1049	/*
1050	 * FIXME: some drivers unfortunately call this function more than once.
1051	 * So we have to check if we've already assigned the reboot notifier.
1052	 *
1053	 * Generally, we can make multiple calls work for most cases, but it
1054	 * does cause problems with parse_mtd_partitions() above (e.g.,
1055	 * cmdlineparts will register partitions more than once).
1056	 */
1057	WARN_ONCE(mtd->_reboot && mtd->reboot_notifier.notifier_call,
1058		  "MTD already registered\n");
1059	if (mtd->_reboot && !mtd->reboot_notifier.notifier_call) {
1060		mtd->reboot_notifier.notifier_call = mtd_reboot_notifier;
1061		register_reboot_notifier(&mtd->reboot_notifier);
1062	}
1063
1064	ret = mtd_otp_nvmem_add(mtd);
1065
1066out:
1067	if (ret && device_is_registered(&mtd->dev))
1068		del_mtd_device(mtd);
1069
1070	return ret;
1071}
1072EXPORT_SYMBOL_GPL(mtd_device_parse_register);
1073
1074/**
1075 * mtd_device_unregister - unregister an existing MTD device.
1076 *
1077 * @master: the MTD device to unregister.  This will unregister both the master
1078 *          and any partitions if registered.
1079 */
1080int mtd_device_unregister(struct mtd_info *master)
1081{
1082	int err;
1083
1084	if (master->_reboot) {
1085		unregister_reboot_notifier(&master->reboot_notifier);
1086		memset(&master->reboot_notifier, 0, sizeof(master->reboot_notifier));
1087	}
1088
1089	nvmem_unregister(master->otp_user_nvmem);
1090	nvmem_unregister(master->otp_factory_nvmem);
 
 
 
1091
1092	err = del_mtd_partitions(master);
1093	if (err)
1094		return err;
1095
1096	if (!device_is_registered(&master->dev))
1097		return 0;
1098
1099	return del_mtd_device(master);
1100}
1101EXPORT_SYMBOL_GPL(mtd_device_unregister);
1102
1103/**
1104 *	register_mtd_user - register a 'user' of MTD devices.
1105 *	@new: pointer to notifier info structure
1106 *
1107 *	Registers a pair of callbacks function to be called upon addition
1108 *	or removal of MTD devices. Causes the 'add' callback to be immediately
1109 *	invoked for each MTD device currently present in the system.
1110 */
1111void register_mtd_user (struct mtd_notifier *new)
1112{
1113	struct mtd_info *mtd;
1114
1115	mutex_lock(&mtd_table_mutex);
1116
1117	list_add(&new->list, &mtd_notifiers);
1118
1119	__module_get(THIS_MODULE);
1120
1121	mtd_for_each_device(mtd)
1122		new->add(mtd);
1123
1124	mutex_unlock(&mtd_table_mutex);
1125}
1126EXPORT_SYMBOL_GPL(register_mtd_user);
1127
1128/**
1129 *	unregister_mtd_user - unregister a 'user' of MTD devices.
1130 *	@old: pointer to notifier info structure
1131 *
1132 *	Removes a callback function pair from the list of 'users' to be
1133 *	notified upon addition or removal of MTD devices. Causes the
1134 *	'remove' callback to be immediately invoked for each MTD device
1135 *	currently present in the system.
1136 */
1137int unregister_mtd_user (struct mtd_notifier *old)
1138{
1139	struct mtd_info *mtd;
1140
1141	mutex_lock(&mtd_table_mutex);
1142
1143	module_put(THIS_MODULE);
1144
1145	mtd_for_each_device(mtd)
1146		old->remove(mtd);
1147
1148	list_del(&old->list);
1149	mutex_unlock(&mtd_table_mutex);
1150	return 0;
1151}
1152EXPORT_SYMBOL_GPL(unregister_mtd_user);
1153
1154/**
1155 *	get_mtd_device - obtain a validated handle for an MTD device
1156 *	@mtd: last known address of the required MTD device
1157 *	@num: internal device number of the required MTD device
1158 *
1159 *	Given a number and NULL address, return the num'th entry in the device
1160 *	table, if any.	Given an address and num == -1, search the device table
1161 *	for a device with that address and return if it's still present. Given
1162 *	both, return the num'th driver only if its address matches. Return
1163 *	error code if not.
1164 */
1165struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
1166{
1167	struct mtd_info *ret = NULL, *other;
1168	int err = -ENODEV;
1169
1170	mutex_lock(&mtd_table_mutex);
1171
1172	if (num == -1) {
1173		mtd_for_each_device(other) {
1174			if (other == mtd) {
1175				ret = mtd;
1176				break;
1177			}
1178		}
1179	} else if (num >= 0) {
1180		ret = idr_find(&mtd_idr, num);
1181		if (mtd && mtd != ret)
1182			ret = NULL;
1183	}
1184
1185	if (!ret) {
1186		ret = ERR_PTR(err);
1187		goto out;
1188	}
1189
1190	err = __get_mtd_device(ret);
1191	if (err)
1192		ret = ERR_PTR(err);
1193out:
1194	mutex_unlock(&mtd_table_mutex);
1195	return ret;
1196}
1197EXPORT_SYMBOL_GPL(get_mtd_device);
1198
1199
1200int __get_mtd_device(struct mtd_info *mtd)
1201{
1202	struct mtd_info *master = mtd_get_master(mtd);
1203	int err;
1204
1205	if (!try_module_get(master->owner))
1206		return -ENODEV;
1207
1208	if (master->_get_device) {
1209		err = master->_get_device(mtd);
1210
1211		if (err) {
1212			module_put(master->owner);
1213			return err;
1214		}
1215	}
1216
1217	master->usecount++;
1218
1219	while (mtd->parent) {
1220		mtd->usecount++;
1221		mtd = mtd->parent;
1222	}
1223
1224	return 0;
1225}
1226EXPORT_SYMBOL_GPL(__get_mtd_device);
1227
1228/**
1229 * of_get_mtd_device_by_node - obtain an MTD device associated with a given node
1230 *
1231 * @np: device tree node
1232 */
1233struct mtd_info *of_get_mtd_device_by_node(struct device_node *np)
1234{
1235	struct mtd_info *mtd = NULL;
1236	struct mtd_info *tmp;
1237	int err;
1238
1239	mutex_lock(&mtd_table_mutex);
1240
1241	err = -EPROBE_DEFER;
1242	mtd_for_each_device(tmp) {
1243		if (mtd_get_of_node(tmp) == np) {
1244			mtd = tmp;
1245			err = __get_mtd_device(mtd);
1246			break;
1247		}
1248	}
1249
1250	mutex_unlock(&mtd_table_mutex);
1251
1252	return err ? ERR_PTR(err) : mtd;
1253}
1254EXPORT_SYMBOL_GPL(of_get_mtd_device_by_node);
1255
1256/**
1257 *	get_mtd_device_nm - obtain a validated handle for an MTD device by
1258 *	device name
1259 *	@name: MTD device name to open
1260 *
1261 * 	This function returns MTD device description structure in case of
1262 * 	success and an error code in case of failure.
1263 */
1264struct mtd_info *get_mtd_device_nm(const char *name)
1265{
1266	int err = -ENODEV;
1267	struct mtd_info *mtd = NULL, *other;
1268
1269	mutex_lock(&mtd_table_mutex);
1270
1271	mtd_for_each_device(other) {
1272		if (!strcmp(name, other->name)) {
1273			mtd = other;
1274			break;
1275		}
1276	}
1277
1278	if (!mtd)
1279		goto out_unlock;
1280
1281	err = __get_mtd_device(mtd);
1282	if (err)
1283		goto out_unlock;
1284
1285	mutex_unlock(&mtd_table_mutex);
1286	return mtd;
1287
1288out_unlock:
1289	mutex_unlock(&mtd_table_mutex);
1290	return ERR_PTR(err);
1291}
1292EXPORT_SYMBOL_GPL(get_mtd_device_nm);
1293
1294void put_mtd_device(struct mtd_info *mtd)
1295{
1296	mutex_lock(&mtd_table_mutex);
1297	__put_mtd_device(mtd);
1298	mutex_unlock(&mtd_table_mutex);
1299
1300}
1301EXPORT_SYMBOL_GPL(put_mtd_device);
1302
1303void __put_mtd_device(struct mtd_info *mtd)
1304{
1305	struct mtd_info *master = mtd_get_master(mtd);
1306
1307	while (mtd->parent) {
1308		--mtd->usecount;
1309		BUG_ON(mtd->usecount < 0);
1310		mtd = mtd->parent;
1311	}
1312
1313	master->usecount--;
1314
1315	if (master->_put_device)
1316		master->_put_device(master);
1317
1318	module_put(master->owner);
1319}
1320EXPORT_SYMBOL_GPL(__put_mtd_device);
1321
1322/*
1323 * Erase is an synchronous operation. Device drivers are epected to return a
1324 * negative error code if the operation failed and update instr->fail_addr
1325 * to point the portion that was not properly erased.
1326 */
1327int mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
1328{
1329	struct mtd_info *master = mtd_get_master(mtd);
1330	u64 mst_ofs = mtd_get_master_ofs(mtd, 0);
1331	struct erase_info adjinstr;
1332	int ret;
1333
1334	instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
1335	adjinstr = *instr;
1336
1337	if (!mtd->erasesize || !master->_erase)
1338		return -ENOTSUPP;
1339
1340	if (instr->addr >= mtd->size || instr->len > mtd->size - instr->addr)
1341		return -EINVAL;
1342	if (!(mtd->flags & MTD_WRITEABLE))
1343		return -EROFS;
1344
1345	if (!instr->len)
1346		return 0;
1347
1348	ledtrig_mtd_activity();
1349
1350	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) {
1351		adjinstr.addr = (loff_t)mtd_div_by_eb(instr->addr, mtd) *
1352				master->erasesize;
1353		adjinstr.len = ((u64)mtd_div_by_eb(instr->addr + instr->len, mtd) *
1354				master->erasesize) -
1355			       adjinstr.addr;
1356	}
1357
1358	adjinstr.addr += mst_ofs;
1359
1360	ret = master->_erase(master, &adjinstr);
1361
1362	if (adjinstr.fail_addr != MTD_FAIL_ADDR_UNKNOWN) {
1363		instr->fail_addr = adjinstr.fail_addr - mst_ofs;
1364		if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) {
1365			instr->fail_addr = mtd_div_by_eb(instr->fail_addr,
1366							 master);
1367			instr->fail_addr *= mtd->erasesize;
1368		}
1369	}
1370
1371	return ret;
1372}
1373EXPORT_SYMBOL_GPL(mtd_erase);
1374
1375/*
1376 * This stuff for eXecute-In-Place. phys is optional and may be set to NULL.
1377 */
1378int mtd_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
1379	      void **virt, resource_size_t *phys)
1380{
1381	struct mtd_info *master = mtd_get_master(mtd);
1382
1383	*retlen = 0;
1384	*virt = NULL;
1385	if (phys)
1386		*phys = 0;
1387	if (!master->_point)
1388		return -EOPNOTSUPP;
1389	if (from < 0 || from >= mtd->size || len > mtd->size - from)
1390		return -EINVAL;
1391	if (!len)
1392		return 0;
1393
1394	from = mtd_get_master_ofs(mtd, from);
1395	return master->_point(master, from, len, retlen, virt, phys);
1396}
1397EXPORT_SYMBOL_GPL(mtd_point);
1398
1399/* We probably shouldn't allow XIP if the unpoint isn't a NULL */
1400int mtd_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
1401{
1402	struct mtd_info *master = mtd_get_master(mtd);
1403
1404	if (!master->_unpoint)
1405		return -EOPNOTSUPP;
1406	if (from < 0 || from >= mtd->size || len > mtd->size - from)
1407		return -EINVAL;
1408	if (!len)
1409		return 0;
1410	return master->_unpoint(master, mtd_get_master_ofs(mtd, from), len);
1411}
1412EXPORT_SYMBOL_GPL(mtd_unpoint);
1413
1414/*
1415 * Allow NOMMU mmap() to directly map the device (if not NULL)
1416 * - return the address to which the offset maps
1417 * - return -ENOSYS to indicate refusal to do the mapping
1418 */
1419unsigned long mtd_get_unmapped_area(struct mtd_info *mtd, unsigned long len,
1420				    unsigned long offset, unsigned long flags)
1421{
1422	size_t retlen;
1423	void *virt;
1424	int ret;
1425
1426	ret = mtd_point(mtd, offset, len, &retlen, &virt, NULL);
1427	if (ret)
1428		return ret;
1429	if (retlen != len) {
1430		mtd_unpoint(mtd, offset, retlen);
1431		return -ENOSYS;
1432	}
1433	return (unsigned long)virt;
1434}
1435EXPORT_SYMBOL_GPL(mtd_get_unmapped_area);
1436
1437static void mtd_update_ecc_stats(struct mtd_info *mtd, struct mtd_info *master,
1438				 const struct mtd_ecc_stats *old_stats)
1439{
1440	struct mtd_ecc_stats diff;
1441
1442	if (master == mtd)
1443		return;
1444
1445	diff = master->ecc_stats;
1446	diff.failed -= old_stats->failed;
1447	diff.corrected -= old_stats->corrected;
1448
1449	while (mtd->parent) {
1450		mtd->ecc_stats.failed += diff.failed;
1451		mtd->ecc_stats.corrected += diff.corrected;
1452		mtd = mtd->parent;
1453	}
1454}
1455
1456int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
1457	     u_char *buf)
1458{
1459	struct mtd_oob_ops ops = {
1460		.len = len,
1461		.datbuf = buf,
1462	};
1463	int ret;
1464
1465	ret = mtd_read_oob(mtd, from, &ops);
1466	*retlen = ops.retlen;
1467
1468	return ret;
1469}
1470EXPORT_SYMBOL_GPL(mtd_read);
1471
1472int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
1473	      const u_char *buf)
1474{
1475	struct mtd_oob_ops ops = {
1476		.len = len,
1477		.datbuf = (u8 *)buf,
1478	};
1479	int ret;
1480
1481	ret = mtd_write_oob(mtd, to, &ops);
1482	*retlen = ops.retlen;
1483
1484	return ret;
1485}
1486EXPORT_SYMBOL_GPL(mtd_write);
1487
1488/*
1489 * In blackbox flight recorder like scenarios we want to make successful writes
1490 * in interrupt context. panic_write() is only intended to be called when its
1491 * known the kernel is about to panic and we need the write to succeed. Since
1492 * the kernel is not going to be running for much longer, this function can
1493 * break locks and delay to ensure the write succeeds (but not sleep).
1494 */
1495int mtd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
1496		    const u_char *buf)
1497{
1498	struct mtd_info *master = mtd_get_master(mtd);
1499
1500	*retlen = 0;
1501	if (!master->_panic_write)
1502		return -EOPNOTSUPP;
1503	if (to < 0 || to >= mtd->size || len > mtd->size - to)
1504		return -EINVAL;
1505	if (!(mtd->flags & MTD_WRITEABLE))
1506		return -EROFS;
1507	if (!len)
1508		return 0;
1509	if (!master->oops_panic_write)
1510		master->oops_panic_write = true;
1511
1512	return master->_panic_write(master, mtd_get_master_ofs(mtd, to), len,
1513				    retlen, buf);
1514}
1515EXPORT_SYMBOL_GPL(mtd_panic_write);
1516
1517static int mtd_check_oob_ops(struct mtd_info *mtd, loff_t offs,
1518			     struct mtd_oob_ops *ops)
1519{
1520	/*
1521	 * Some users are setting ->datbuf or ->oobbuf to NULL, but are leaving
1522	 * ->len or ->ooblen uninitialized. Force ->len and ->ooblen to 0 in
1523	 *  this case.
1524	 */
1525	if (!ops->datbuf)
1526		ops->len = 0;
1527
1528	if (!ops->oobbuf)
1529		ops->ooblen = 0;
1530
1531	if (offs < 0 || offs + ops->len > mtd->size)
1532		return -EINVAL;
1533
1534	if (ops->ooblen) {
1535		size_t maxooblen;
1536
1537		if (ops->ooboffs >= mtd_oobavail(mtd, ops))
1538			return -EINVAL;
1539
1540		maxooblen = ((size_t)(mtd_div_by_ws(mtd->size, mtd) -
1541				      mtd_div_by_ws(offs, mtd)) *
1542			     mtd_oobavail(mtd, ops)) - ops->ooboffs;
1543		if (ops->ooblen > maxooblen)
1544			return -EINVAL;
1545	}
1546
1547	return 0;
1548}
1549
1550static int mtd_read_oob_std(struct mtd_info *mtd, loff_t from,
1551			    struct mtd_oob_ops *ops)
1552{
1553	struct mtd_info *master = mtd_get_master(mtd);
1554	int ret;
1555
1556	from = mtd_get_master_ofs(mtd, from);
1557	if (master->_read_oob)
1558		ret = master->_read_oob(master, from, ops);
1559	else
1560		ret = master->_read(master, from, ops->len, &ops->retlen,
1561				    ops->datbuf);
1562
1563	return ret;
1564}
1565
1566static int mtd_write_oob_std(struct mtd_info *mtd, loff_t to,
1567			     struct mtd_oob_ops *ops)
1568{
1569	struct mtd_info *master = mtd_get_master(mtd);
1570	int ret;
1571
1572	to = mtd_get_master_ofs(mtd, to);
1573	if (master->_write_oob)
1574		ret = master->_write_oob(master, to, ops);
1575	else
1576		ret = master->_write(master, to, ops->len, &ops->retlen,
1577				     ops->datbuf);
1578
1579	return ret;
1580}
1581
1582static int mtd_io_emulated_slc(struct mtd_info *mtd, loff_t start, bool read,
1583			       struct mtd_oob_ops *ops)
1584{
1585	struct mtd_info *master = mtd_get_master(mtd);
1586	int ngroups = mtd_pairing_groups(master);
1587	int npairs = mtd_wunit_per_eb(master) / ngroups;
1588	struct mtd_oob_ops adjops = *ops;
1589	unsigned int wunit, oobavail;
1590	struct mtd_pairing_info info;
1591	int max_bitflips = 0;
1592	u32 ebofs, pageofs;
1593	loff_t base, pos;
1594
1595	ebofs = mtd_mod_by_eb(start, mtd);
1596	base = (loff_t)mtd_div_by_eb(start, mtd) * master->erasesize;
1597	info.group = 0;
1598	info.pair = mtd_div_by_ws(ebofs, mtd);
1599	pageofs = mtd_mod_by_ws(ebofs, mtd);
1600	oobavail = mtd_oobavail(mtd, ops);
1601
1602	while (ops->retlen < ops->len || ops->oobretlen < ops->ooblen) {
1603		int ret;
1604
1605		if (info.pair >= npairs) {
1606			info.pair = 0;
1607			base += master->erasesize;
1608		}
1609
1610		wunit = mtd_pairing_info_to_wunit(master, &info);
1611		pos = mtd_wunit_to_offset(mtd, base, wunit);
1612
1613		adjops.len = ops->len - ops->retlen;
1614		if (adjops.len > mtd->writesize - pageofs)
1615			adjops.len = mtd->writesize - pageofs;
1616
1617		adjops.ooblen = ops->ooblen - ops->oobretlen;
1618		if (adjops.ooblen > oobavail - adjops.ooboffs)
1619			adjops.ooblen = oobavail - adjops.ooboffs;
1620
1621		if (read) {
1622			ret = mtd_read_oob_std(mtd, pos + pageofs, &adjops);
1623			if (ret > 0)
1624				max_bitflips = max(max_bitflips, ret);
1625		} else {
1626			ret = mtd_write_oob_std(mtd, pos + pageofs, &adjops);
1627		}
1628
1629		if (ret < 0)
1630			return ret;
1631
1632		max_bitflips = max(max_bitflips, ret);
1633		ops->retlen += adjops.retlen;
1634		ops->oobretlen += adjops.oobretlen;
1635		adjops.datbuf += adjops.retlen;
1636		adjops.oobbuf += adjops.oobretlen;
1637		adjops.ooboffs = 0;
1638		pageofs = 0;
1639		info.pair++;
1640	}
1641
1642	return max_bitflips;
1643}
1644
1645int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
1646{
1647	struct mtd_info *master = mtd_get_master(mtd);
1648	struct mtd_ecc_stats old_stats = master->ecc_stats;
1649	int ret_code;
1650
1651	ops->retlen = ops->oobretlen = 0;
1652
1653	ret_code = mtd_check_oob_ops(mtd, from, ops);
1654	if (ret_code)
1655		return ret_code;
1656
1657	ledtrig_mtd_activity();
1658
1659	/* Check the validity of a potential fallback on mtd->_read */
1660	if (!master->_read_oob && (!master->_read || ops->oobbuf))
1661		return -EOPNOTSUPP;
1662
1663	if (ops->stats)
1664		memset(ops->stats, 0, sizeof(*ops->stats));
1665
1666	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
1667		ret_code = mtd_io_emulated_slc(mtd, from, true, ops);
1668	else
1669		ret_code = mtd_read_oob_std(mtd, from, ops);
1670
1671	mtd_update_ecc_stats(mtd, master, &old_stats);
1672
1673	/*
1674	 * In cases where ops->datbuf != NULL, mtd->_read_oob() has semantics
1675	 * similar to mtd->_read(), returning a non-negative integer
1676	 * representing max bitflips. In other cases, mtd->_read_oob() may
1677	 * return -EUCLEAN. In all cases, perform similar logic to mtd_read().
1678	 */
1679	if (unlikely(ret_code < 0))
1680		return ret_code;
1681	if (mtd->ecc_strength == 0)
1682		return 0;	/* device lacks ecc */
1683	if (ops->stats)
1684		ops->stats->max_bitflips = ret_code;
1685	return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
1686}
1687EXPORT_SYMBOL_GPL(mtd_read_oob);
1688
1689int mtd_write_oob(struct mtd_info *mtd, loff_t to,
1690				struct mtd_oob_ops *ops)
1691{
1692	struct mtd_info *master = mtd_get_master(mtd);
1693	int ret;
1694
1695	ops->retlen = ops->oobretlen = 0;
1696
1697	if (!(mtd->flags & MTD_WRITEABLE))
1698		return -EROFS;
1699
1700	ret = mtd_check_oob_ops(mtd, to, ops);
1701	if (ret)
1702		return ret;
1703
1704	ledtrig_mtd_activity();
1705
1706	/* Check the validity of a potential fallback on mtd->_write */
1707	if (!master->_write_oob && (!master->_write || ops->oobbuf))
1708		return -EOPNOTSUPP;
1709
1710	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
1711		return mtd_io_emulated_slc(mtd, to, false, ops);
1712
1713	return mtd_write_oob_std(mtd, to, ops);
1714}
1715EXPORT_SYMBOL_GPL(mtd_write_oob);
1716
1717/**
1718 * mtd_ooblayout_ecc - Get the OOB region definition of a specific ECC section
1719 * @mtd: MTD device structure
1720 * @section: ECC section. Depending on the layout you may have all the ECC
1721 *	     bytes stored in a single contiguous section, or one section
1722 *	     per ECC chunk (and sometime several sections for a single ECC
1723 *	     ECC chunk)
1724 * @oobecc: OOB region struct filled with the appropriate ECC position
1725 *	    information
1726 *
1727 * This function returns ECC section information in the OOB area. If you want
1728 * to get all the ECC bytes information, then you should call
1729 * mtd_ooblayout_ecc(mtd, section++, oobecc) until it returns -ERANGE.
1730 *
1731 * Returns zero on success, a negative error code otherwise.
1732 */
1733int mtd_ooblayout_ecc(struct mtd_info *mtd, int section,
1734		      struct mtd_oob_region *oobecc)
1735{
1736	struct mtd_info *master = mtd_get_master(mtd);
1737
1738	memset(oobecc, 0, sizeof(*oobecc));
1739
1740	if (!master || section < 0)
1741		return -EINVAL;
1742
1743	if (!master->ooblayout || !master->ooblayout->ecc)
1744		return -ENOTSUPP;
1745
1746	return master->ooblayout->ecc(master, section, oobecc);
1747}
1748EXPORT_SYMBOL_GPL(mtd_ooblayout_ecc);
1749
1750/**
1751 * mtd_ooblayout_free - Get the OOB region definition of a specific free
1752 *			section
1753 * @mtd: MTD device structure
1754 * @section: Free section you are interested in. Depending on the layout
1755 *	     you may have all the free bytes stored in a single contiguous
1756 *	     section, or one section per ECC chunk plus an extra section
1757 *	     for the remaining bytes (or other funky layout).
1758 * @oobfree: OOB region struct filled with the appropriate free position
1759 *	     information
1760 *
1761 * This function returns free bytes position in the OOB area. If you want
1762 * to get all the free bytes information, then you should call
1763 * mtd_ooblayout_free(mtd, section++, oobfree) until it returns -ERANGE.
1764 *
1765 * Returns zero on success, a negative error code otherwise.
1766 */
1767int mtd_ooblayout_free(struct mtd_info *mtd, int section,
1768		       struct mtd_oob_region *oobfree)
1769{
1770	struct mtd_info *master = mtd_get_master(mtd);
1771
1772	memset(oobfree, 0, sizeof(*oobfree));
1773
1774	if (!master || section < 0)
1775		return -EINVAL;
1776
1777	if (!master->ooblayout || !master->ooblayout->free)
1778		return -ENOTSUPP;
1779
1780	return master->ooblayout->free(master, section, oobfree);
1781}
1782EXPORT_SYMBOL_GPL(mtd_ooblayout_free);
1783
1784/**
1785 * mtd_ooblayout_find_region - Find the region attached to a specific byte
1786 * @mtd: mtd info structure
1787 * @byte: the byte we are searching for
1788 * @sectionp: pointer where the section id will be stored
1789 * @oobregion: used to retrieve the ECC position
1790 * @iter: iterator function. Should be either mtd_ooblayout_free or
1791 *	  mtd_ooblayout_ecc depending on the region type you're searching for
1792 *
1793 * This function returns the section id and oobregion information of a
1794 * specific byte. For example, say you want to know where the 4th ECC byte is
1795 * stored, you'll use:
1796 *
1797 * mtd_ooblayout_find_region(mtd, 3, &section, &oobregion, mtd_ooblayout_ecc);
1798 *
1799 * Returns zero on success, a negative error code otherwise.
1800 */
1801static int mtd_ooblayout_find_region(struct mtd_info *mtd, int byte,
1802				int *sectionp, struct mtd_oob_region *oobregion,
1803				int (*iter)(struct mtd_info *,
1804					    int section,
1805					    struct mtd_oob_region *oobregion))
1806{
1807	int pos = 0, ret, section = 0;
1808
1809	memset(oobregion, 0, sizeof(*oobregion));
1810
1811	while (1) {
1812		ret = iter(mtd, section, oobregion);
1813		if (ret)
1814			return ret;
1815
1816		if (pos + oobregion->length > byte)
1817			break;
1818
1819		pos += oobregion->length;
1820		section++;
1821	}
1822
1823	/*
1824	 * Adjust region info to make it start at the beginning at the
1825	 * 'start' ECC byte.
1826	 */
1827	oobregion->offset += byte - pos;
1828	oobregion->length -= byte - pos;
1829	*sectionp = section;
1830
1831	return 0;
1832}
1833
1834/**
1835 * mtd_ooblayout_find_eccregion - Find the ECC region attached to a specific
1836 *				  ECC byte
1837 * @mtd: mtd info structure
1838 * @eccbyte: the byte we are searching for
1839 * @section: pointer where the section id will be stored
1840 * @oobregion: OOB region information
1841 *
1842 * Works like mtd_ooblayout_find_region() except it searches for a specific ECC
1843 * byte.
1844 *
1845 * Returns zero on success, a negative error code otherwise.
1846 */
1847int mtd_ooblayout_find_eccregion(struct mtd_info *mtd, int eccbyte,
1848				 int *section,
1849				 struct mtd_oob_region *oobregion)
1850{
1851	return mtd_ooblayout_find_region(mtd, eccbyte, section, oobregion,
1852					 mtd_ooblayout_ecc);
1853}
1854EXPORT_SYMBOL_GPL(mtd_ooblayout_find_eccregion);
1855
1856/**
1857 * mtd_ooblayout_get_bytes - Extract OOB bytes from the oob buffer
1858 * @mtd: mtd info structure
1859 * @buf: destination buffer to store OOB bytes
1860 * @oobbuf: OOB buffer
1861 * @start: first byte to retrieve
1862 * @nbytes: number of bytes to retrieve
1863 * @iter: section iterator
1864 *
1865 * Extract bytes attached to a specific category (ECC or free)
1866 * from the OOB buffer and copy them into buf.
1867 *
1868 * Returns zero on success, a negative error code otherwise.
1869 */
1870static int mtd_ooblayout_get_bytes(struct mtd_info *mtd, u8 *buf,
1871				const u8 *oobbuf, int start, int nbytes,
1872				int (*iter)(struct mtd_info *,
1873					    int section,
1874					    struct mtd_oob_region *oobregion))
1875{
1876	struct mtd_oob_region oobregion;
1877	int section, ret;
1878
1879	ret = mtd_ooblayout_find_region(mtd, start, &section,
1880					&oobregion, iter);
1881
1882	while (!ret) {
1883		int cnt;
1884
1885		cnt = min_t(int, nbytes, oobregion.length);
1886		memcpy(buf, oobbuf + oobregion.offset, cnt);
1887		buf += cnt;
1888		nbytes -= cnt;
1889
1890		if (!nbytes)
1891			break;
1892
1893		ret = iter(mtd, ++section, &oobregion);
1894	}
1895
1896	return ret;
1897}
1898
1899/**
1900 * mtd_ooblayout_set_bytes - put OOB bytes into the oob buffer
1901 * @mtd: mtd info structure
1902 * @buf: source buffer to get OOB bytes from
1903 * @oobbuf: OOB buffer
1904 * @start: first OOB byte to set
1905 * @nbytes: number of OOB bytes to set
1906 * @iter: section iterator
1907 *
1908 * Fill the OOB buffer with data provided in buf. The category (ECC or free)
1909 * is selected by passing the appropriate iterator.
1910 *
1911 * Returns zero on success, a negative error code otherwise.
1912 */
1913static int mtd_ooblayout_set_bytes(struct mtd_info *mtd, const u8 *buf,
1914				u8 *oobbuf, int start, int nbytes,
1915				int (*iter)(struct mtd_info *,
1916					    int section,
1917					    struct mtd_oob_region *oobregion))
1918{
1919	struct mtd_oob_region oobregion;
1920	int section, ret;
1921
1922	ret = mtd_ooblayout_find_region(mtd, start, &section,
1923					&oobregion, iter);
1924
1925	while (!ret) {
1926		int cnt;
1927
1928		cnt = min_t(int, nbytes, oobregion.length);
1929		memcpy(oobbuf + oobregion.offset, buf, cnt);
1930		buf += cnt;
1931		nbytes -= cnt;
1932
1933		if (!nbytes)
1934			break;
1935
1936		ret = iter(mtd, ++section, &oobregion);
1937	}
1938
1939	return ret;
1940}
1941
1942/**
1943 * mtd_ooblayout_count_bytes - count the number of bytes in a OOB category
1944 * @mtd: mtd info structure
1945 * @iter: category iterator
1946 *
1947 * Count the number of bytes in a given category.
1948 *
1949 * Returns a positive value on success, a negative error code otherwise.
1950 */
1951static int mtd_ooblayout_count_bytes(struct mtd_info *mtd,
1952				int (*iter)(struct mtd_info *,
1953					    int section,
1954					    struct mtd_oob_region *oobregion))
1955{
1956	struct mtd_oob_region oobregion;
1957	int section = 0, ret, nbytes = 0;
1958
1959	while (1) {
1960		ret = iter(mtd, section++, &oobregion);
1961		if (ret) {
1962			if (ret == -ERANGE)
1963				ret = nbytes;
1964			break;
1965		}
1966
1967		nbytes += oobregion.length;
1968	}
1969
1970	return ret;
1971}
1972
1973/**
1974 * mtd_ooblayout_get_eccbytes - extract ECC bytes from the oob buffer
1975 * @mtd: mtd info structure
1976 * @eccbuf: destination buffer to store ECC bytes
1977 * @oobbuf: OOB buffer
1978 * @start: first ECC byte to retrieve
1979 * @nbytes: number of ECC bytes to retrieve
1980 *
1981 * Works like mtd_ooblayout_get_bytes(), except it acts on ECC bytes.
1982 *
1983 * Returns zero on success, a negative error code otherwise.
1984 */
1985int mtd_ooblayout_get_eccbytes(struct mtd_info *mtd, u8 *eccbuf,
1986			       const u8 *oobbuf, int start, int nbytes)
1987{
1988	return mtd_ooblayout_get_bytes(mtd, eccbuf, oobbuf, start, nbytes,
1989				       mtd_ooblayout_ecc);
1990}
1991EXPORT_SYMBOL_GPL(mtd_ooblayout_get_eccbytes);
1992
1993/**
1994 * mtd_ooblayout_set_eccbytes - set ECC bytes into the oob buffer
1995 * @mtd: mtd info structure
1996 * @eccbuf: source buffer to get ECC bytes from
1997 * @oobbuf: OOB buffer
1998 * @start: first ECC byte to set
1999 * @nbytes: number of ECC bytes to set
2000 *
2001 * Works like mtd_ooblayout_set_bytes(), except it acts on ECC bytes.
2002 *
2003 * Returns zero on success, a negative error code otherwise.
2004 */
2005int mtd_ooblayout_set_eccbytes(struct mtd_info *mtd, const u8 *eccbuf,
2006			       u8 *oobbuf, int start, int nbytes)
2007{
2008	return mtd_ooblayout_set_bytes(mtd, eccbuf, oobbuf, start, nbytes,
2009				       mtd_ooblayout_ecc);
2010}
2011EXPORT_SYMBOL_GPL(mtd_ooblayout_set_eccbytes);
2012
2013/**
2014 * mtd_ooblayout_get_databytes - extract data bytes from the oob buffer
2015 * @mtd: mtd info structure
2016 * @databuf: destination buffer to store ECC bytes
2017 * @oobbuf: OOB buffer
2018 * @start: first ECC byte to retrieve
2019 * @nbytes: number of ECC bytes to retrieve
2020 *
2021 * Works like mtd_ooblayout_get_bytes(), except it acts on free bytes.
2022 *
2023 * Returns zero on success, a negative error code otherwise.
2024 */
2025int mtd_ooblayout_get_databytes(struct mtd_info *mtd, u8 *databuf,
2026				const u8 *oobbuf, int start, int nbytes)
2027{
2028	return mtd_ooblayout_get_bytes(mtd, databuf, oobbuf, start, nbytes,
2029				       mtd_ooblayout_free);
2030}
2031EXPORT_SYMBOL_GPL(mtd_ooblayout_get_databytes);
2032
2033/**
2034 * mtd_ooblayout_set_databytes - set data bytes into the oob buffer
2035 * @mtd: mtd info structure
2036 * @databuf: source buffer to get data bytes from
2037 * @oobbuf: OOB buffer
2038 * @start: first ECC byte to set
2039 * @nbytes: number of ECC bytes to set
2040 *
2041 * Works like mtd_ooblayout_set_bytes(), except it acts on free bytes.
2042 *
2043 * Returns zero on success, a negative error code otherwise.
2044 */
2045int mtd_ooblayout_set_databytes(struct mtd_info *mtd, const u8 *databuf,
2046				u8 *oobbuf, int start, int nbytes)
2047{
2048	return mtd_ooblayout_set_bytes(mtd, databuf, oobbuf, start, nbytes,
2049				       mtd_ooblayout_free);
2050}
2051EXPORT_SYMBOL_GPL(mtd_ooblayout_set_databytes);
2052
2053/**
2054 * mtd_ooblayout_count_freebytes - count the number of free bytes in OOB
2055 * @mtd: mtd info structure
2056 *
2057 * Works like mtd_ooblayout_count_bytes(), except it count free bytes.
2058 *
2059 * Returns zero on success, a negative error code otherwise.
2060 */
2061int mtd_ooblayout_count_freebytes(struct mtd_info *mtd)
2062{
2063	return mtd_ooblayout_count_bytes(mtd, mtd_ooblayout_free);
2064}
2065EXPORT_SYMBOL_GPL(mtd_ooblayout_count_freebytes);
2066
2067/**
2068 * mtd_ooblayout_count_eccbytes - count the number of ECC bytes in OOB
2069 * @mtd: mtd info structure
2070 *
2071 * Works like mtd_ooblayout_count_bytes(), except it count ECC bytes.
2072 *
2073 * Returns zero on success, a negative error code otherwise.
2074 */
2075int mtd_ooblayout_count_eccbytes(struct mtd_info *mtd)
2076{
2077	return mtd_ooblayout_count_bytes(mtd, mtd_ooblayout_ecc);
2078}
2079EXPORT_SYMBOL_GPL(mtd_ooblayout_count_eccbytes);
2080
2081/*
2082 * Method to access the protection register area, present in some flash
2083 * devices. The user data is one time programmable but the factory data is read
2084 * only.
2085 */
2086int mtd_get_fact_prot_info(struct mtd_info *mtd, size_t len, size_t *retlen,
2087			   struct otp_info *buf)
2088{
2089	struct mtd_info *master = mtd_get_master(mtd);
2090
2091	if (!master->_get_fact_prot_info)
2092		return -EOPNOTSUPP;
2093	if (!len)
2094		return 0;
2095	return master->_get_fact_prot_info(master, len, retlen, buf);
2096}
2097EXPORT_SYMBOL_GPL(mtd_get_fact_prot_info);
2098
2099int mtd_read_fact_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
2100			   size_t *retlen, u_char *buf)
2101{
2102	struct mtd_info *master = mtd_get_master(mtd);
2103
2104	*retlen = 0;
2105	if (!master->_read_fact_prot_reg)
2106		return -EOPNOTSUPP;
2107	if (!len)
2108		return 0;
2109	return master->_read_fact_prot_reg(master, from, len, retlen, buf);
2110}
2111EXPORT_SYMBOL_GPL(mtd_read_fact_prot_reg);
2112
2113int mtd_get_user_prot_info(struct mtd_info *mtd, size_t len, size_t *retlen,
2114			   struct otp_info *buf)
2115{
2116	struct mtd_info *master = mtd_get_master(mtd);
2117
2118	if (!master->_get_user_prot_info)
2119		return -EOPNOTSUPP;
2120	if (!len)
2121		return 0;
2122	return master->_get_user_prot_info(master, len, retlen, buf);
2123}
2124EXPORT_SYMBOL_GPL(mtd_get_user_prot_info);
2125
2126int mtd_read_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
2127			   size_t *retlen, u_char *buf)
2128{
2129	struct mtd_info *master = mtd_get_master(mtd);
2130
2131	*retlen = 0;
2132	if (!master->_read_user_prot_reg)
2133		return -EOPNOTSUPP;
2134	if (!len)
2135		return 0;
2136	return master->_read_user_prot_reg(master, from, len, retlen, buf);
2137}
2138EXPORT_SYMBOL_GPL(mtd_read_user_prot_reg);
2139
2140int mtd_write_user_prot_reg(struct mtd_info *mtd, loff_t to, size_t len,
2141			    size_t *retlen, const u_char *buf)
2142{
2143	struct mtd_info *master = mtd_get_master(mtd);
2144	int ret;
2145
2146	*retlen = 0;
2147	if (!master->_write_user_prot_reg)
2148		return -EOPNOTSUPP;
2149	if (!len)
2150		return 0;
2151	ret = master->_write_user_prot_reg(master, to, len, retlen, buf);
2152	if (ret)
2153		return ret;
2154
2155	/*
2156	 * If no data could be written at all, we are out of memory and
2157	 * must return -ENOSPC.
2158	 */
2159	return (*retlen) ? 0 : -ENOSPC;
2160}
2161EXPORT_SYMBOL_GPL(mtd_write_user_prot_reg);
2162
2163int mtd_lock_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len)
2164{
2165	struct mtd_info *master = mtd_get_master(mtd);
2166
2167	if (!master->_lock_user_prot_reg)
2168		return -EOPNOTSUPP;
2169	if (!len)
2170		return 0;
2171	return master->_lock_user_prot_reg(master, from, len);
2172}
2173EXPORT_SYMBOL_GPL(mtd_lock_user_prot_reg);
2174
2175int mtd_erase_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len)
2176{
2177	struct mtd_info *master = mtd_get_master(mtd);
2178
2179	if (!master->_erase_user_prot_reg)
2180		return -EOPNOTSUPP;
2181	if (!len)
2182		return 0;
2183	return master->_erase_user_prot_reg(master, from, len);
2184}
2185EXPORT_SYMBOL_GPL(mtd_erase_user_prot_reg);
2186
2187/* Chip-supported device locking */
2188int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
2189{
2190	struct mtd_info *master = mtd_get_master(mtd);
2191
2192	if (!master->_lock)
2193		return -EOPNOTSUPP;
2194	if (ofs < 0 || ofs >= mtd->size || len > mtd->size - ofs)
2195		return -EINVAL;
2196	if (!len)
2197		return 0;
2198
2199	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) {
2200		ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize;
2201		len = (u64)mtd_div_by_eb(len, mtd) * master->erasesize;
2202	}
2203
2204	return master->_lock(master, mtd_get_master_ofs(mtd, ofs), len);
2205}
2206EXPORT_SYMBOL_GPL(mtd_lock);
2207
2208int mtd_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
2209{
2210	struct mtd_info *master = mtd_get_master(mtd);
2211
2212	if (!master->_unlock)
2213		return -EOPNOTSUPP;
2214	if (ofs < 0 || ofs >= mtd->size || len > mtd->size - ofs)
2215		return -EINVAL;
2216	if (!len)
2217		return 0;
2218
2219	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) {
2220		ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize;
2221		len = (u64)mtd_div_by_eb(len, mtd) * master->erasesize;
2222	}
2223
2224	return master->_unlock(master, mtd_get_master_ofs(mtd, ofs), len);
2225}
2226EXPORT_SYMBOL_GPL(mtd_unlock);
2227
2228int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
2229{
2230	struct mtd_info *master = mtd_get_master(mtd);
2231
2232	if (!master->_is_locked)
2233		return -EOPNOTSUPP;
2234	if (ofs < 0 || ofs >= mtd->size || len > mtd->size - ofs)
2235		return -EINVAL;
2236	if (!len)
2237		return 0;
2238
2239	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) {
2240		ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize;
2241		len = (u64)mtd_div_by_eb(len, mtd) * master->erasesize;
2242	}
2243
2244	return master->_is_locked(master, mtd_get_master_ofs(mtd, ofs), len);
2245}
2246EXPORT_SYMBOL_GPL(mtd_is_locked);
2247
2248int mtd_block_isreserved(struct mtd_info *mtd, loff_t ofs)
2249{
2250	struct mtd_info *master = mtd_get_master(mtd);
2251
2252	if (ofs < 0 || ofs >= mtd->size)
2253		return -EINVAL;
2254	if (!master->_block_isreserved)
2255		return 0;
2256
2257	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
2258		ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize;
2259
2260	return master->_block_isreserved(master, mtd_get_master_ofs(mtd, ofs));
2261}
2262EXPORT_SYMBOL_GPL(mtd_block_isreserved);
2263
2264int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs)
2265{
2266	struct mtd_info *master = mtd_get_master(mtd);
2267
2268	if (ofs < 0 || ofs >= mtd->size)
2269		return -EINVAL;
2270	if (!master->_block_isbad)
2271		return 0;
2272
2273	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
2274		ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize;
2275
2276	return master->_block_isbad(master, mtd_get_master_ofs(mtd, ofs));
2277}
2278EXPORT_SYMBOL_GPL(mtd_block_isbad);
2279
2280int mtd_block_markbad(struct mtd_info *mtd, loff_t ofs)
2281{
2282	struct mtd_info *master = mtd_get_master(mtd);
2283	int ret;
2284
2285	if (!master->_block_markbad)
2286		return -EOPNOTSUPP;
2287	if (ofs < 0 || ofs >= mtd->size)
2288		return -EINVAL;
2289	if (!(mtd->flags & MTD_WRITEABLE))
2290		return -EROFS;
2291
2292	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
2293		ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize;
2294
2295	ret = master->_block_markbad(master, mtd_get_master_ofs(mtd, ofs));
2296	if (ret)
2297		return ret;
2298
2299	while (mtd->parent) {
2300		mtd->ecc_stats.badblocks++;
2301		mtd = mtd->parent;
2302	}
2303
2304	return 0;
2305}
2306EXPORT_SYMBOL_GPL(mtd_block_markbad);
2307
2308/*
2309 * default_mtd_writev - the default writev method
2310 * @mtd: mtd device description object pointer
2311 * @vecs: the vectors to write
2312 * @count: count of vectors in @vecs
2313 * @to: the MTD device offset to write to
2314 * @retlen: on exit contains the count of bytes written to the MTD device.
2315 *
2316 * This function returns zero in case of success and a negative error code in
2317 * case of failure.
2318 */
2319static int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
2320			      unsigned long count, loff_t to, size_t *retlen)
2321{
2322	unsigned long i;
2323	size_t totlen = 0, thislen;
2324	int ret = 0;
2325
2326	for (i = 0; i < count; i++) {
2327		if (!vecs[i].iov_len)
2328			continue;
2329		ret = mtd_write(mtd, to, vecs[i].iov_len, &thislen,
2330				vecs[i].iov_base);
2331		totlen += thislen;
2332		if (ret || thislen != vecs[i].iov_len)
2333			break;
2334		to += vecs[i].iov_len;
2335	}
2336	*retlen = totlen;
2337	return ret;
2338}
2339
2340/*
2341 * mtd_writev - the vector-based MTD write method
2342 * @mtd: mtd device description object pointer
2343 * @vecs: the vectors to write
2344 * @count: count of vectors in @vecs
2345 * @to: the MTD device offset to write to
2346 * @retlen: on exit contains the count of bytes written to the MTD device.
2347 *
2348 * This function returns zero in case of success and a negative error code in
2349 * case of failure.
2350 */
2351int mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
2352	       unsigned long count, loff_t to, size_t *retlen)
2353{
2354	struct mtd_info *master = mtd_get_master(mtd);
2355
2356	*retlen = 0;
2357	if (!(mtd->flags & MTD_WRITEABLE))
2358		return -EROFS;
2359
2360	if (!master->_writev)
2361		return default_mtd_writev(mtd, vecs, count, to, retlen);
2362
2363	return master->_writev(master, vecs, count,
2364			       mtd_get_master_ofs(mtd, to), retlen);
2365}
2366EXPORT_SYMBOL_GPL(mtd_writev);
2367
2368/**
2369 * mtd_kmalloc_up_to - allocate a contiguous buffer up to the specified size
2370 * @mtd: mtd device description object pointer
2371 * @size: a pointer to the ideal or maximum size of the allocation, points
2372 *        to the actual allocation size on success.
2373 *
2374 * This routine attempts to allocate a contiguous kernel buffer up to
2375 * the specified size, backing off the size of the request exponentially
2376 * until the request succeeds or until the allocation size falls below
2377 * the system page size. This attempts to make sure it does not adversely
2378 * impact system performance, so when allocating more than one page, we
2379 * ask the memory allocator to avoid re-trying, swapping, writing back
2380 * or performing I/O.
2381 *
2382 * Note, this function also makes sure that the allocated buffer is aligned to
2383 * the MTD device's min. I/O unit, i.e. the "mtd->writesize" value.
2384 *
2385 * This is called, for example by mtd_{read,write} and jffs2_scan_medium,
2386 * to handle smaller (i.e. degraded) buffer allocations under low- or
2387 * fragmented-memory situations where such reduced allocations, from a
2388 * requested ideal, are allowed.
2389 *
2390 * Returns a pointer to the allocated buffer on success; otherwise, NULL.
2391 */
2392void *mtd_kmalloc_up_to(const struct mtd_info *mtd, size_t *size)
2393{
2394	gfp_t flags = __GFP_NOWARN | __GFP_DIRECT_RECLAIM | __GFP_NORETRY;
2395	size_t min_alloc = max_t(size_t, mtd->writesize, PAGE_SIZE);
2396	void *kbuf;
2397
2398	*size = min_t(size_t, *size, KMALLOC_MAX_SIZE);
2399
2400	while (*size > min_alloc) {
2401		kbuf = kmalloc(*size, flags);
2402		if (kbuf)
2403			return kbuf;
2404
2405		*size >>= 1;
2406		*size = ALIGN(*size, mtd->writesize);
2407	}
2408
2409	/*
2410	 * For the last resort allocation allow 'kmalloc()' to do all sorts of
2411	 * things (write-back, dropping caches, etc) by using GFP_KERNEL.
2412	 */
2413	return kmalloc(*size, GFP_KERNEL);
2414}
2415EXPORT_SYMBOL_GPL(mtd_kmalloc_up_to);
2416
2417#ifdef CONFIG_PROC_FS
2418
2419/*====================================================================*/
2420/* Support for /proc/mtd */
2421
2422static int mtd_proc_show(struct seq_file *m, void *v)
2423{
2424	struct mtd_info *mtd;
2425
2426	seq_puts(m, "dev:    size   erasesize  name\n");
2427	mutex_lock(&mtd_table_mutex);
2428	mtd_for_each_device(mtd) {
2429		seq_printf(m, "mtd%d: %8.8llx %8.8x \"%s\"\n",
2430			   mtd->index, (unsigned long long)mtd->size,
2431			   mtd->erasesize, mtd->name);
2432	}
2433	mutex_unlock(&mtd_table_mutex);
2434	return 0;
2435}
2436#endif /* CONFIG_PROC_FS */
2437
2438/*====================================================================*/
2439/* Init code */
2440
2441static struct backing_dev_info * __init mtd_bdi_init(const char *name)
2442{
2443	struct backing_dev_info *bdi;
2444	int ret;
2445
2446	bdi = bdi_alloc(NUMA_NO_NODE);
2447	if (!bdi)
2448		return ERR_PTR(-ENOMEM);
2449	bdi->ra_pages = 0;
2450	bdi->io_pages = 0;
2451
2452	/*
2453	 * We put '-0' suffix to the name to get the same name format as we
2454	 * used to get. Since this is called only once, we get a unique name. 
2455	 */
2456	ret = bdi_register(bdi, "%.28s-0", name);
2457	if (ret)
2458		bdi_put(bdi);
2459
2460	return ret ? ERR_PTR(ret) : bdi;
2461}
2462
2463static struct proc_dir_entry *proc_mtd;
2464
2465static int __init init_mtd(void)
2466{
2467	int ret;
2468
2469	ret = class_register(&mtd_class);
2470	if (ret)
2471		goto err_reg;
2472
2473	mtd_bdi = mtd_bdi_init("mtd");
2474	if (IS_ERR(mtd_bdi)) {
2475		ret = PTR_ERR(mtd_bdi);
2476		goto err_bdi;
2477	}
2478
2479	proc_mtd = proc_create_single("mtd", 0, NULL, mtd_proc_show);
2480
2481	ret = init_mtdchar();
2482	if (ret)
2483		goto out_procfs;
2484
2485	dfs_dir_mtd = debugfs_create_dir("mtd", NULL);
2486	debugfs_create_bool("expert_analysis_mode", 0600, dfs_dir_mtd,
2487			    &mtd_expert_analysis_mode);
2488
2489	return 0;
2490
2491out_procfs:
2492	if (proc_mtd)
2493		remove_proc_entry("mtd", NULL);
2494	bdi_unregister(mtd_bdi);
2495	bdi_put(mtd_bdi);
2496err_bdi:
2497	class_unregister(&mtd_class);
2498err_reg:
2499	pr_err("Error registering mtd class or bdi: %d\n", ret);
2500	return ret;
2501}
2502
2503static void __exit cleanup_mtd(void)
2504{
2505	debugfs_remove_recursive(dfs_dir_mtd);
2506	cleanup_mtdchar();
2507	if (proc_mtd)
2508		remove_proc_entry("mtd", NULL);
2509	class_unregister(&mtd_class);
2510	bdi_unregister(mtd_bdi);
2511	bdi_put(mtd_bdi);
2512	idr_destroy(&mtd_idr);
2513}
2514
2515module_init(init_mtd);
2516module_exit(cleanup_mtd);
2517
2518MODULE_LICENSE("GPL");
2519MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
2520MODULE_DESCRIPTION("Core MTD registration and access routines");