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/random.h>
  27#include <linux/slab.h>
  28#include <linux/reboot.h>
  29#include <linux/leds.h>
  30#include <linux/debugfs.h>
  31#include <linux/nvmem-provider.h>
  32#include <linux/root_dev.h>
  33#include <linux/error-injection.h>
  34
  35#include <linux/mtd/mtd.h>
  36#include <linux/mtd/partitions.h>
  37
  38#include "mtdcore.h"
  39
  40struct backing_dev_info *mtd_bdi;
  41
  42#ifdef CONFIG_PM_SLEEP
  43
  44static int mtd_cls_suspend(struct device *dev)
  45{
  46	struct mtd_info *mtd = dev_get_drvdata(dev);
  47
  48	return mtd ? mtd_suspend(mtd) : 0;
  49}
  50
  51static int mtd_cls_resume(struct device *dev)
  52{
  53	struct mtd_info *mtd = dev_get_drvdata(dev);
  54
  55	if (mtd)
  56		mtd_resume(mtd);
  57	return 0;
  58}
  59
  60static SIMPLE_DEV_PM_OPS(mtd_cls_pm_ops, mtd_cls_suspend, mtd_cls_resume);
  61#define MTD_CLS_PM_OPS (&mtd_cls_pm_ops)
  62#else
  63#define MTD_CLS_PM_OPS NULL
  64#endif
  65
  66static struct class mtd_class = {
  67	.name = "mtd",
 
  68	.pm = MTD_CLS_PM_OPS,
  69};
  70
  71static DEFINE_IDR(mtd_idr);
  72
  73/* These are exported solely for the purpose of mtd_blkdevs.c. You
  74   should not use them for _anything_ else */
  75DEFINE_MUTEX(mtd_table_mutex);
  76EXPORT_SYMBOL_GPL(mtd_table_mutex);
  77
  78struct mtd_info *__mtd_next_device(int i)
  79{
  80	return idr_get_next(&mtd_idr, &i);
  81}
  82EXPORT_SYMBOL_GPL(__mtd_next_device);
  83
  84static LIST_HEAD(mtd_notifiers);
  85
  86
  87#define MTD_DEVT(index) MKDEV(MTD_CHAR_MAJOR, (index)*2)
  88
  89/* REVISIT once MTD uses the driver model better, whoever allocates
  90 * the mtd_info will probably want to use the release() hook...
  91 */
  92static void mtd_release(struct device *dev)
  93{
  94	struct mtd_info *mtd = dev_get_drvdata(dev);
  95	dev_t index = MTD_DEVT(mtd->index);
  96
  97	idr_remove(&mtd_idr, mtd->index);
  98	of_node_put(mtd_get_of_node(mtd));
  99
 100	if (mtd_is_partition(mtd))
 101		release_mtd_partition(mtd);
 102
 103	/* remove /dev/mtdXro node */
 104	device_destroy(&mtd_class, index + 1);
 105}
 106
 107static void mtd_device_release(struct kref *kref)
 108{
 109	struct mtd_info *mtd = container_of(kref, struct mtd_info, refcnt);
 110	bool is_partition = mtd_is_partition(mtd);
 111
 112	debugfs_remove_recursive(mtd->dbg.dfs_dir);
 113
 114	/* Try to remove the NVMEM provider */
 115	nvmem_unregister(mtd->nvmem);
 116
 117	device_unregister(&mtd->dev);
 118
 119	/*
 120	 *  Clear dev so mtd can be safely re-registered later if desired.
 121	 *  Should not be done for partition,
 122	 *  as it was already destroyed in device_unregister().
 123	 */
 124	if (!is_partition)
 125		memset(&mtd->dev, 0, sizeof(mtd->dev));
 126
 127	module_put(THIS_MODULE);
 128}
 129
 130#define MTD_DEVICE_ATTR_RO(name) \
 131static DEVICE_ATTR(name, 0444, mtd_##name##_show, NULL)
 132
 133#define MTD_DEVICE_ATTR_RW(name) \
 134static DEVICE_ATTR(name, 0644, mtd_##name##_show, mtd_##name##_store)
 135
 136static ssize_t mtd_type_show(struct device *dev,
 137		struct device_attribute *attr, char *buf)
 138{
 139	struct mtd_info *mtd = dev_get_drvdata(dev);
 140	char *type;
 141
 142	switch (mtd->type) {
 143	case MTD_ABSENT:
 144		type = "absent";
 145		break;
 146	case MTD_RAM:
 147		type = "ram";
 148		break;
 149	case MTD_ROM:
 150		type = "rom";
 151		break;
 152	case MTD_NORFLASH:
 153		type = "nor";
 154		break;
 155	case MTD_NANDFLASH:
 156		type = "nand";
 157		break;
 158	case MTD_DATAFLASH:
 159		type = "dataflash";
 160		break;
 161	case MTD_UBIVOLUME:
 162		type = "ubi";
 163		break;
 164	case MTD_MLCNANDFLASH:
 165		type = "mlc-nand";
 166		break;
 167	default:
 168		type = "unknown";
 169	}
 170
 171	return sysfs_emit(buf, "%s\n", type);
 172}
 173MTD_DEVICE_ATTR_RO(type);
 174
 175static ssize_t mtd_flags_show(struct device *dev,
 176		struct device_attribute *attr, char *buf)
 177{
 178	struct mtd_info *mtd = dev_get_drvdata(dev);
 179
 180	return sysfs_emit(buf, "0x%lx\n", (unsigned long)mtd->flags);
 181}
 182MTD_DEVICE_ATTR_RO(flags);
 183
 184static ssize_t mtd_size_show(struct device *dev,
 185		struct device_attribute *attr, char *buf)
 186{
 187	struct mtd_info *mtd = dev_get_drvdata(dev);
 188
 189	return sysfs_emit(buf, "%llu\n", (unsigned long long)mtd->size);
 
 190}
 191MTD_DEVICE_ATTR_RO(size);
 192
 193static ssize_t mtd_erasesize_show(struct device *dev,
 194		struct device_attribute *attr, char *buf)
 195{
 196	struct mtd_info *mtd = dev_get_drvdata(dev);
 197
 198	return sysfs_emit(buf, "%lu\n", (unsigned long)mtd->erasesize);
 199}
 200MTD_DEVICE_ATTR_RO(erasesize);
 201
 202static ssize_t mtd_writesize_show(struct device *dev,
 203		struct device_attribute *attr, char *buf)
 204{
 205	struct mtd_info *mtd = dev_get_drvdata(dev);
 206
 207	return sysfs_emit(buf, "%lu\n", (unsigned long)mtd->writesize);
 208}
 209MTD_DEVICE_ATTR_RO(writesize);
 210
 211static ssize_t mtd_subpagesize_show(struct device *dev,
 212		struct device_attribute *attr, char *buf)
 213{
 214	struct mtd_info *mtd = dev_get_drvdata(dev);
 215	unsigned int subpagesize = mtd->writesize >> mtd->subpage_sft;
 216
 217	return sysfs_emit(buf, "%u\n", subpagesize);
 218}
 219MTD_DEVICE_ATTR_RO(subpagesize);
 220
 221static ssize_t mtd_oobsize_show(struct device *dev,
 222		struct device_attribute *attr, char *buf)
 223{
 224	struct mtd_info *mtd = dev_get_drvdata(dev);
 225
 226	return sysfs_emit(buf, "%lu\n", (unsigned long)mtd->oobsize);
 227}
 228MTD_DEVICE_ATTR_RO(oobsize);
 229
 230static ssize_t mtd_oobavail_show(struct device *dev,
 231				 struct device_attribute *attr, char *buf)
 232{
 233	struct mtd_info *mtd = dev_get_drvdata(dev);
 234
 235	return sysfs_emit(buf, "%u\n", mtd->oobavail);
 236}
 237MTD_DEVICE_ATTR_RO(oobavail);
 238
 239static ssize_t mtd_numeraseregions_show(struct device *dev,
 240		struct device_attribute *attr, char *buf)
 241{
 242	struct mtd_info *mtd = dev_get_drvdata(dev);
 243
 244	return sysfs_emit(buf, "%u\n", mtd->numeraseregions);
 245}
 246MTD_DEVICE_ATTR_RO(numeraseregions);
 
 247
 248static ssize_t mtd_name_show(struct device *dev,
 249		struct device_attribute *attr, char *buf)
 250{
 251	struct mtd_info *mtd = dev_get_drvdata(dev);
 252
 253	return sysfs_emit(buf, "%s\n", mtd->name);
 254}
 255MTD_DEVICE_ATTR_RO(name);
 256
 257static ssize_t mtd_ecc_strength_show(struct device *dev,
 258				     struct device_attribute *attr, char *buf)
 259{
 260	struct mtd_info *mtd = dev_get_drvdata(dev);
 261
 262	return sysfs_emit(buf, "%u\n", mtd->ecc_strength);
 263}
 264MTD_DEVICE_ATTR_RO(ecc_strength);
 265
 266static ssize_t mtd_bitflip_threshold_show(struct device *dev,
 267					  struct device_attribute *attr,
 268					  char *buf)
 269{
 270	struct mtd_info *mtd = dev_get_drvdata(dev);
 271
 272	return sysfs_emit(buf, "%u\n", mtd->bitflip_threshold);
 273}
 274
 275static ssize_t mtd_bitflip_threshold_store(struct device *dev,
 276					   struct device_attribute *attr,
 277					   const char *buf, size_t count)
 278{
 279	struct mtd_info *mtd = dev_get_drvdata(dev);
 280	unsigned int bitflip_threshold;
 281	int retval;
 282
 283	retval = kstrtouint(buf, 0, &bitflip_threshold);
 284	if (retval)
 285		return retval;
 286
 287	mtd->bitflip_threshold = bitflip_threshold;
 288	return count;
 289}
 290MTD_DEVICE_ATTR_RW(bitflip_threshold);
 
 
 291
 292static ssize_t mtd_ecc_step_size_show(struct device *dev,
 293		struct device_attribute *attr, char *buf)
 294{
 295	struct mtd_info *mtd = dev_get_drvdata(dev);
 296
 297	return sysfs_emit(buf, "%u\n", mtd->ecc_step_size);
 298
 299}
 300MTD_DEVICE_ATTR_RO(ecc_step_size);
 301
 302static ssize_t mtd_corrected_bits_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->corrected);
 309}
 310MTD_DEVICE_ATTR_RO(corrected_bits);	/* ecc stats corrected */
 
 311
 312static ssize_t mtd_ecc_failures_show(struct device *dev,
 313		struct device_attribute *attr, char *buf)
 314{
 315	struct mtd_info *mtd = dev_get_drvdata(dev);
 316	struct mtd_ecc_stats *ecc_stats = &mtd->ecc_stats;
 317
 318	return sysfs_emit(buf, "%u\n", ecc_stats->failed);
 319}
 320MTD_DEVICE_ATTR_RO(ecc_failures);	/* ecc stats errors */
 321
 322static ssize_t mtd_bad_blocks_show(struct device *dev,
 323		struct device_attribute *attr, char *buf)
 324{
 325	struct mtd_info *mtd = dev_get_drvdata(dev);
 326	struct mtd_ecc_stats *ecc_stats = &mtd->ecc_stats;
 327
 328	return sysfs_emit(buf, "%u\n", ecc_stats->badblocks);
 329}
 330MTD_DEVICE_ATTR_RO(bad_blocks);
 331
 332static ssize_t mtd_bbt_blocks_show(struct device *dev,
 333		struct device_attribute *attr, char *buf)
 334{
 335	struct mtd_info *mtd = dev_get_drvdata(dev);
 336	struct mtd_ecc_stats *ecc_stats = &mtd->ecc_stats;
 337
 338	return sysfs_emit(buf, "%u\n", ecc_stats->bbtblocks);
 339}
 340MTD_DEVICE_ATTR_RO(bbt_blocks);
 341
 342static struct attribute *mtd_attrs[] = {
 343	&dev_attr_type.attr,
 344	&dev_attr_flags.attr,
 345	&dev_attr_size.attr,
 346	&dev_attr_erasesize.attr,
 347	&dev_attr_writesize.attr,
 348	&dev_attr_subpagesize.attr,
 349	&dev_attr_oobsize.attr,
 350	&dev_attr_oobavail.attr,
 351	&dev_attr_numeraseregions.attr,
 352	&dev_attr_name.attr,
 353	&dev_attr_ecc_strength.attr,
 354	&dev_attr_ecc_step_size.attr,
 355	&dev_attr_corrected_bits.attr,
 356	&dev_attr_ecc_failures.attr,
 357	&dev_attr_bad_blocks.attr,
 358	&dev_attr_bbt_blocks.attr,
 359	&dev_attr_bitflip_threshold.attr,
 360	NULL,
 361};
 362ATTRIBUTE_GROUPS(mtd);
 363
 364static const struct device_type mtd_devtype = {
 365	.name		= "mtd",
 366	.groups		= mtd_groups,
 367	.release	= mtd_release,
 368};
 369
 370static bool mtd_expert_analysis_mode;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 371
 372#ifdef CONFIG_DEBUG_FS
 373bool mtd_check_expert_analysis_mode(void)
 374{
 375	const char *mtd_expert_analysis_warning =
 376		"Bad block checks have been entirely disabled.\n"
 377		"This is only reserved for post-mortem forensics and debug purposes.\n"
 378		"Never enable this mode if you do not know what you are doing!\n";
 379
 380	return WARN_ONCE(mtd_expert_analysis_mode, mtd_expert_analysis_warning);
 381}
 382EXPORT_SYMBOL_GPL(mtd_check_expert_analysis_mode);
 383#endif
 
 
 
 
 
 
 
 
 
 
 384
 385static struct dentry *dfs_dir_mtd;
 386
 387static void mtd_debugfs_populate(struct mtd_info *mtd)
 388{
 389	struct device *dev = &mtd->dev;
 
 390
 391	if (IS_ERR_OR_NULL(dfs_dir_mtd))
 392		return;
 393
 394	mtd->dbg.dfs_dir = debugfs_create_dir(dev_name(dev), dfs_dir_mtd);
 
 
 
 
 
 
 
 
 
 395}
 396
 397#ifndef CONFIG_MMU
 398unsigned mtd_mmap_capabilities(struct mtd_info *mtd)
 399{
 400	switch (mtd->type) {
 401	case MTD_RAM:
 402		return NOMMU_MAP_COPY | NOMMU_MAP_DIRECT | NOMMU_MAP_EXEC |
 403			NOMMU_MAP_READ | NOMMU_MAP_WRITE;
 404	case MTD_ROM:
 405		return NOMMU_MAP_COPY | NOMMU_MAP_DIRECT | NOMMU_MAP_EXEC |
 406			NOMMU_MAP_READ;
 407	default:
 408		return NOMMU_MAP_COPY;
 409	}
 410}
 411EXPORT_SYMBOL_GPL(mtd_mmap_capabilities);
 412#endif
 413
 414static int mtd_reboot_notifier(struct notifier_block *n, unsigned long state,
 415			       void *cmd)
 416{
 417	struct mtd_info *mtd;
 418
 419	mtd = container_of(n, struct mtd_info, reboot_notifier);
 420	mtd->_reboot(mtd);
 421
 422	return NOTIFY_DONE;
 423}
 424
 425/**
 426 * mtd_wunit_to_pairing_info - get pairing information of a wunit
 427 * @mtd: pointer to new MTD device info structure
 428 * @wunit: write unit we are interested in
 429 * @info: returned pairing information
 430 *
 431 * Retrieve pairing information associated to the wunit.
 432 * This is mainly useful when dealing with MLC/TLC NANDs where pages can be
 433 * paired together, and where programming a page may influence the page it is
 434 * paired with.
 435 * The notion of page is replaced by the term wunit (write-unit) to stay
 436 * consistent with the ->writesize field.
 437 *
 438 * The @wunit argument can be extracted from an absolute offset using
 439 * mtd_offset_to_wunit(). @info is filled with the pairing information attached
 440 * to @wunit.
 441 *
 442 * From the pairing info the MTD user can find all the wunits paired with
 443 * @wunit using the following loop:
 444 *
 445 * for (i = 0; i < mtd_pairing_groups(mtd); i++) {
 446 *	info.pair = i;
 447 *	mtd_pairing_info_to_wunit(mtd, &info);
 448 *	...
 449 * }
 450 */
 451int mtd_wunit_to_pairing_info(struct mtd_info *mtd, int wunit,
 452			      struct mtd_pairing_info *info)
 453{
 454	struct mtd_info *master = mtd_get_master(mtd);
 455	int npairs = mtd_wunit_per_eb(master) / mtd_pairing_groups(master);
 456
 457	if (wunit < 0 || wunit >= npairs)
 458		return -EINVAL;
 459
 460	if (master->pairing && master->pairing->get_info)
 461		return master->pairing->get_info(master, wunit, info);
 462
 463	info->group = 0;
 464	info->pair = wunit;
 465
 466	return 0;
 467}
 468EXPORT_SYMBOL_GPL(mtd_wunit_to_pairing_info);
 469
 470/**
 471 * mtd_pairing_info_to_wunit - get wunit from pairing information
 472 * @mtd: pointer to new MTD device info structure
 473 * @info: pairing information struct
 474 *
 475 * Returns a positive number representing the wunit associated to the info
 476 * struct, or a negative error code.
 477 *
 478 * This is the reverse of mtd_wunit_to_pairing_info(), and can help one to
 479 * iterate over all wunits of a given pair (see mtd_wunit_to_pairing_info()
 480 * doc).
 481 *
 482 * It can also be used to only program the first page of each pair (i.e.
 483 * page attached to group 0), which allows one to use an MLC NAND in
 484 * software-emulated SLC mode:
 485 *
 486 * info.group = 0;
 487 * npairs = mtd_wunit_per_eb(mtd) / mtd_pairing_groups(mtd);
 488 * for (info.pair = 0; info.pair < npairs; info.pair++) {
 489 *	wunit = mtd_pairing_info_to_wunit(mtd, &info);
 490 *	mtd_write(mtd, mtd_wunit_to_offset(mtd, blkoffs, wunit),
 491 *		  mtd->writesize, &retlen, buf + (i * mtd->writesize));
 492 * }
 493 */
 494int mtd_pairing_info_to_wunit(struct mtd_info *mtd,
 495			      const struct mtd_pairing_info *info)
 496{
 497	struct mtd_info *master = mtd_get_master(mtd);
 498	int ngroups = mtd_pairing_groups(master);
 499	int npairs = mtd_wunit_per_eb(master) / ngroups;
 500
 501	if (!info || info->pair < 0 || info->pair >= npairs ||
 502	    info->group < 0 || info->group >= ngroups)
 503		return -EINVAL;
 504
 505	if (master->pairing && master->pairing->get_wunit)
 506		return mtd->pairing->get_wunit(master, info);
 507
 508	return info->pair;
 509}
 510EXPORT_SYMBOL_GPL(mtd_pairing_info_to_wunit);
 511
 512/**
 513 * mtd_pairing_groups - get the number of pairing groups
 514 * @mtd: pointer to new MTD device info structure
 515 *
 516 * Returns the number of pairing groups.
 517 *
 518 * This number is usually equal to the number of bits exposed by a single
 519 * cell, and can be used in conjunction with mtd_pairing_info_to_wunit()
 520 * to iterate over all pages of a given pair.
 521 */
 522int mtd_pairing_groups(struct mtd_info *mtd)
 523{
 524	struct mtd_info *master = mtd_get_master(mtd);
 525
 526	if (!master->pairing || !master->pairing->ngroups)
 527		return 1;
 528
 529	return master->pairing->ngroups;
 530}
 531EXPORT_SYMBOL_GPL(mtd_pairing_groups);
 532
 533static int mtd_nvmem_reg_read(void *priv, unsigned int offset,
 534			      void *val, size_t bytes)
 535{
 536	struct mtd_info *mtd = priv;
 537	size_t retlen;
 538	int err;
 539
 540	err = mtd_read(mtd, offset, bytes, &retlen, val);
 541	if (err && err != -EUCLEAN)
 542		return err;
 543
 544	return retlen == bytes ? 0 : -EIO;
 545}
 546
 547static int mtd_nvmem_add(struct mtd_info *mtd)
 548{
 549	struct device_node *node = mtd_get_of_node(mtd);
 550	struct nvmem_config config = {};
 551
 552	config.id = NVMEM_DEVID_NONE;
 553	config.dev = &mtd->dev;
 554	config.name = dev_name(&mtd->dev);
 555	config.owner = THIS_MODULE;
 556	config.add_legacy_fixed_of_cells = of_device_is_compatible(node, "nvmem-cells");
 557	config.reg_read = mtd_nvmem_reg_read;
 558	config.size = mtd->size;
 559	config.word_size = 1;
 560	config.stride = 1;
 561	config.read_only = true;
 562	config.root_only = true;
 563	config.ignore_wp = true;
 564	config.priv = mtd;
 565
 566	mtd->nvmem = nvmem_register(&config);
 567	if (IS_ERR(mtd->nvmem)) {
 568		/* Just ignore if there is no NVMEM support in the kernel */
 569		if (PTR_ERR(mtd->nvmem) == -EOPNOTSUPP)
 570			mtd->nvmem = NULL;
 571		else
 572			return dev_err_probe(&mtd->dev, PTR_ERR(mtd->nvmem),
 573					     "Failed to register NVMEM device\n");
 574	}
 575
 576	return 0;
 577}
 578
 579static void mtd_check_of_node(struct mtd_info *mtd)
 580{
 581	struct device_node *partitions, *parent_dn, *mtd_dn = NULL;
 582	const char *pname, *prefix = "partition-";
 583	int plen, mtd_name_len, offset, prefix_len;
 584
 585	/* Check if MTD already has a device node */
 586	if (mtd_get_of_node(mtd))
 587		return;
 588
 589	if (!mtd_is_partition(mtd))
 590		return;
 591
 592	parent_dn = of_node_get(mtd_get_of_node(mtd->parent));
 593	if (!parent_dn)
 594		return;
 595
 596	if (mtd_is_partition(mtd->parent))
 597		partitions = of_node_get(parent_dn);
 598	else
 599		partitions = of_get_child_by_name(parent_dn, "partitions");
 600	if (!partitions)
 601		goto exit_parent;
 602
 603	prefix_len = strlen(prefix);
 604	mtd_name_len = strlen(mtd->name);
 605
 606	/* Search if a partition is defined with the same name */
 607	for_each_child_of_node(partitions, mtd_dn) {
 608		/* Skip partition with no/wrong prefix */
 609		if (!of_node_name_prefix(mtd_dn, prefix))
 610			continue;
 611
 612		/* Label have priority. Check that first */
 613		if (!of_property_read_string(mtd_dn, "label", &pname)) {
 614			offset = 0;
 615		} else {
 616			pname = mtd_dn->name;
 617			offset = prefix_len;
 618		}
 619
 620		plen = strlen(pname) - offset;
 621		if (plen == mtd_name_len &&
 622		    !strncmp(mtd->name, pname + offset, plen)) {
 623			mtd_set_of_node(mtd, mtd_dn);
 624			of_node_put(mtd_dn);
 625			break;
 626		}
 627	}
 628
 629	of_node_put(partitions);
 630exit_parent:
 631	of_node_put(parent_dn);
 632}
 633
 634/**
 635 *	add_mtd_device - register an MTD device
 636 *	@mtd: pointer to new MTD device info structure
 637 *
 638 *	Add a device to the list of MTD devices present in the system, and
 639 *	notify each currently active MTD 'user' of its arrival. Returns
 640 *	zero on success or non-zero on failure.
 641 */
 642
 643int add_mtd_device(struct mtd_info *mtd)
 644{
 645	struct device_node *np = mtd_get_of_node(mtd);
 646	struct mtd_info *master = mtd_get_master(mtd);
 647	struct mtd_notifier *not;
 648	int i, error, ofidx;
 649
 650	/*
 651	 * May occur, for instance, on buggy drivers which call
 652	 * mtd_device_parse_register() multiple times on the same master MTD,
 653	 * especially with CONFIG_MTD_PARTITIONED_MASTER=y.
 654	 */
 655	if (WARN_ONCE(mtd->dev.type, "MTD already registered\n"))
 656		return -EEXIST;
 657
 658	BUG_ON(mtd->writesize == 0);
 659
 660	/*
 661	 * MTD drivers should implement ->_{write,read}() or
 662	 * ->_{write,read}_oob(), but not both.
 663	 */
 664	if (WARN_ON((mtd->_write && mtd->_write_oob) ||
 665		    (mtd->_read && mtd->_read_oob)))
 666		return -EINVAL;
 667
 668	if (WARN_ON((!mtd->erasesize || !master->_erase) &&
 669		    !(mtd->flags & MTD_NO_ERASE)))
 670		return -EINVAL;
 671
 672	/*
 673	 * MTD_SLC_ON_MLC_EMULATION can only be set on partitions, when the
 674	 * master is an MLC NAND and has a proper pairing scheme defined.
 675	 * We also reject masters that implement ->_writev() for now, because
 676	 * NAND controller drivers don't implement this hook, and adding the
 677	 * SLC -> MLC address/length conversion to this path is useless if we
 678	 * don't have a user.
 679	 */
 680	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION &&
 681	    (!mtd_is_partition(mtd) || master->type != MTD_MLCNANDFLASH ||
 682	     !master->pairing || master->_writev))
 683		return -EINVAL;
 684
 685	mutex_lock(&mtd_table_mutex);
 686
 687	ofidx = -1;
 688	if (np)
 689		ofidx = of_alias_get_id(np, "mtd");
 690	if (ofidx >= 0)
 691		i = idr_alloc(&mtd_idr, mtd, ofidx, ofidx + 1, GFP_KERNEL);
 692	else
 693		i = idr_alloc(&mtd_idr, mtd, 0, 0, GFP_KERNEL);
 694	if (i < 0) {
 695		error = i;
 696		goto fail_locked;
 697	}
 698
 699	mtd->index = i;
 700	kref_init(&mtd->refcnt);
 701
 702	/* default value if not set by driver */
 703	if (mtd->bitflip_threshold == 0)
 704		mtd->bitflip_threshold = mtd->ecc_strength;
 705
 706	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) {
 707		int ngroups = mtd_pairing_groups(master);
 708
 709		mtd->erasesize /= ngroups;
 710		mtd->size = (u64)mtd_div_by_eb(mtd->size, master) *
 711			    mtd->erasesize;
 712	}
 713
 714	if (is_power_of_2(mtd->erasesize))
 715		mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
 716	else
 717		mtd->erasesize_shift = 0;
 718
 719	if (is_power_of_2(mtd->writesize))
 720		mtd->writesize_shift = ffs(mtd->writesize) - 1;
 721	else
 722		mtd->writesize_shift = 0;
 723
 724	mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
 725	mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;
 726
 727	/* Some chips always power up locked. Unlock them now */
 728	if ((mtd->flags & MTD_WRITEABLE) && (mtd->flags & MTD_POWERUP_LOCK)) {
 729		error = mtd_unlock(mtd, 0, mtd->size);
 730		if (error && error != -EOPNOTSUPP)
 731			printk(KERN_WARNING
 732			       "%s: unlock failed, writes may not work\n",
 733			       mtd->name);
 734		/* Ignore unlock failures? */
 735		error = 0;
 736	}
 737
 738	/* Caller should have set dev.parent to match the
 739	 * physical device, if appropriate.
 740	 */
 741	mtd->dev.type = &mtd_devtype;
 742	mtd->dev.class = &mtd_class;
 743	mtd->dev.devt = MTD_DEVT(i);
 744	dev_set_name(&mtd->dev, "mtd%d", i);
 745	dev_set_drvdata(&mtd->dev, mtd);
 746	mtd_check_of_node(mtd);
 747	of_node_get(mtd_get_of_node(mtd));
 748	error = device_register(&mtd->dev);
 749	if (error) {
 750		put_device(&mtd->dev);
 751		goto fail_added;
 752	}
 753
 754	/* Add the nvmem provider */
 755	error = mtd_nvmem_add(mtd);
 756	if (error)
 757		goto fail_nvmem_add;
 758
 759	mtd_debugfs_populate(mtd);
 760
 761	device_create(&mtd_class, mtd->dev.parent, MTD_DEVT(i) + 1, NULL,
 762		      "mtd%dro", i);
 763
 764	pr_debug("mtd: Giving out device %d to %s\n", i, mtd->name);
 765	/* No need to get a refcount on the module containing
 766	   the notifier, since we hold the mtd_table_mutex */
 767	list_for_each_entry(not, &mtd_notifiers, list)
 768		not->add(mtd);
 769
 770	mutex_unlock(&mtd_table_mutex);
 771
 772	if (of_property_read_bool(mtd_get_of_node(mtd), "linux,rootfs")) {
 773		if (IS_BUILTIN(CONFIG_MTD)) {
 774			pr_info("mtd: setting mtd%d (%s) as root device\n", mtd->index, mtd->name);
 775			ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
 776		} else {
 777			pr_warn("mtd: can't set mtd%d (%s) as root device - mtd must be builtin\n",
 778				mtd->index, mtd->name);
 779		}
 780	}
 781
 782	/* We _know_ we aren't being removed, because
 783	   our caller is still holding us here. So none
 784	   of this try_ nonsense, and no bitching about it
 785	   either. :) */
 786	__module_get(THIS_MODULE);
 787	return 0;
 788
 789fail_nvmem_add:
 790	device_unregister(&mtd->dev);
 791fail_added:
 792	of_node_put(mtd_get_of_node(mtd));
 793	idr_remove(&mtd_idr, i);
 794fail_locked:
 795	mutex_unlock(&mtd_table_mutex);
 796	return error;
 797}
 798
 799/**
 800 *	del_mtd_device - unregister an MTD device
 801 *	@mtd: pointer to MTD device info structure
 802 *
 803 *	Remove a device from the list of MTD devices present in the system,
 804 *	and notify each currently active MTD 'user' of its departure.
 805 *	Returns zero on success or 1 on failure, which currently will happen
 806 *	if the requested device does not appear to be present in the list.
 807 */
 808
 809int del_mtd_device(struct mtd_info *mtd)
 810{
 811	int ret;
 812	struct mtd_notifier *not;
 813
 814	mutex_lock(&mtd_table_mutex);
 815
 
 
 816	if (idr_find(&mtd_idr, mtd->index) != mtd) {
 817		ret = -ENODEV;
 818		goto out_error;
 819	}
 820
 821	/* No need to get a refcount on the module containing
 822		the notifier, since we hold the mtd_table_mutex */
 823	list_for_each_entry(not, &mtd_notifiers, list)
 824		not->remove(mtd);
 825
 826	kref_put(&mtd->refcnt, mtd_device_release);
 827	ret = 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 828
 829out_error:
 830	mutex_unlock(&mtd_table_mutex);
 831	return ret;
 832}
 833
 834/*
 835 * Set a few defaults based on the parent devices, if not provided by the
 836 * driver
 837 */
 838static void mtd_set_dev_defaults(struct mtd_info *mtd)
 839{
 840	if (mtd->dev.parent) {
 841		if (!mtd->owner && mtd->dev.parent->driver)
 842			mtd->owner = mtd->dev.parent->driver->owner;
 843		if (!mtd->name)
 844			mtd->name = dev_name(mtd->dev.parent);
 845	} else {
 846		pr_debug("mtd device won't show a device symlink in sysfs\n");
 847	}
 848
 849	INIT_LIST_HEAD(&mtd->partitions);
 850	mutex_init(&mtd->master.partitions_lock);
 851	mutex_init(&mtd->master.chrdev_lock);
 852}
 853
 854static ssize_t mtd_otp_size(struct mtd_info *mtd, bool is_user)
 855{
 856	struct otp_info *info;
 857	ssize_t size = 0;
 858	unsigned int i;
 859	size_t retlen;
 860	int ret;
 861
 862	info = kmalloc(PAGE_SIZE, GFP_KERNEL);
 863	if (!info)
 864		return -ENOMEM;
 865
 866	if (is_user)
 867		ret = mtd_get_user_prot_info(mtd, PAGE_SIZE, &retlen, info);
 868	else
 869		ret = mtd_get_fact_prot_info(mtd, PAGE_SIZE, &retlen, info);
 870	if (ret)
 871		goto err;
 872
 873	for (i = 0; i < retlen / sizeof(*info); i++)
 874		size += info[i].length;
 875
 876	kfree(info);
 877	return size;
 878
 879err:
 880	kfree(info);
 881
 882	/* ENODATA means there is no OTP region. */
 883	return ret == -ENODATA ? 0 : ret;
 884}
 885
 886static struct nvmem_device *mtd_otp_nvmem_register(struct mtd_info *mtd,
 887						   const char *compatible,
 888						   int size,
 889						   nvmem_reg_read_t reg_read)
 890{
 891	struct nvmem_device *nvmem = NULL;
 892	struct nvmem_config config = {};
 893	struct device_node *np;
 894
 895	/* DT binding is optional */
 896	np = of_get_compatible_child(mtd->dev.of_node, compatible);
 897
 898	/* OTP nvmem will be registered on the physical device */
 899	config.dev = mtd->dev.parent;
 900	config.name = compatible;
 901	config.id = NVMEM_DEVID_AUTO;
 902	config.owner = THIS_MODULE;
 903	config.add_legacy_fixed_of_cells = !mtd_type_is_nand(mtd);
 904	config.type = NVMEM_TYPE_OTP;
 905	config.root_only = true;
 906	config.ignore_wp = true;
 907	config.reg_read = reg_read;
 908	config.size = size;
 909	config.of_node = np;
 910	config.priv = mtd;
 911
 912	nvmem = nvmem_register(&config);
 913	/* Just ignore if there is no NVMEM support in the kernel */
 914	if (IS_ERR(nvmem) && PTR_ERR(nvmem) == -EOPNOTSUPP)
 915		nvmem = NULL;
 916
 917	of_node_put(np);
 918
 919	return nvmem;
 920}
 921
 922static int mtd_nvmem_user_otp_reg_read(void *priv, unsigned int offset,
 923				       void *val, size_t bytes)
 924{
 925	struct mtd_info *mtd = priv;
 926	size_t retlen;
 927	int ret;
 928
 929	ret = mtd_read_user_prot_reg(mtd, offset, bytes, &retlen, val);
 930	if (ret)
 931		return ret;
 932
 933	return retlen == bytes ? 0 : -EIO;
 934}
 935
 936static int mtd_nvmem_fact_otp_reg_read(void *priv, unsigned int offset,
 937				       void *val, size_t bytes)
 938{
 939	struct mtd_info *mtd = priv;
 940	size_t retlen;
 941	int ret;
 942
 943	ret = mtd_read_fact_prot_reg(mtd, offset, bytes, &retlen, val);
 944	if (ret)
 945		return ret;
 946
 947	return retlen == bytes ? 0 : -EIO;
 948}
 949
 950static int mtd_otp_nvmem_add(struct mtd_info *mtd)
 951{
 952	struct device *dev = mtd->dev.parent;
 953	struct nvmem_device *nvmem;
 954	ssize_t size;
 955	int err;
 956
 957	if (mtd->_get_user_prot_info && mtd->_read_user_prot_reg) {
 958		size = mtd_otp_size(mtd, true);
 959		if (size < 0) {
 960			err = size;
 961			goto err;
 962		}
 963
 964		if (size > 0) {
 965			nvmem = mtd_otp_nvmem_register(mtd, "user-otp", size,
 966						       mtd_nvmem_user_otp_reg_read);
 967			if (IS_ERR(nvmem)) {
 968				err = PTR_ERR(nvmem);
 969				goto err;
 970			}
 971			mtd->otp_user_nvmem = nvmem;
 972		}
 973	}
 974
 975	if (mtd->_get_fact_prot_info && mtd->_read_fact_prot_reg) {
 976		size = mtd_otp_size(mtd, false);
 977		if (size < 0) {
 978			err = size;
 979			goto err;
 980		}
 981
 982		if (size > 0) {
 983			/*
 984			 * The factory OTP contains thing such as a unique serial
 985			 * number and is small, so let's read it out and put it
 986			 * into the entropy pool.
 987			 */
 988			void *otp;
 989
 990			otp = kmalloc(size, GFP_KERNEL);
 991			if (!otp) {
 992				err = -ENOMEM;
 993				goto err;
 994			}
 995			err = mtd_nvmem_fact_otp_reg_read(mtd, 0, otp, size);
 996			if (err < 0) {
 997				kfree(otp);
 998				goto err;
 999			}
1000			add_device_randomness(otp, err);
1001			kfree(otp);
1002
1003			nvmem = mtd_otp_nvmem_register(mtd, "factory-otp", size,
1004						       mtd_nvmem_fact_otp_reg_read);
1005			if (IS_ERR(nvmem)) {
1006				err = PTR_ERR(nvmem);
1007				goto err;
1008			}
1009			mtd->otp_factory_nvmem = nvmem;
1010		}
1011	}
1012
1013	return 0;
1014
1015err:
1016	nvmem_unregister(mtd->otp_user_nvmem);
1017	/* Don't report error if OTP is not supported. */
1018	if (err == -EOPNOTSUPP)
1019		return 0;
1020	return dev_err_probe(dev, err, "Failed to register OTP NVMEM device\n");
1021}
1022
1023/**
1024 * mtd_device_parse_register - parse partitions and register an MTD device.
1025 *
1026 * @mtd: the MTD device to register
1027 * @types: the list of MTD partition probes to try, see
1028 *         'parse_mtd_partitions()' for more information
1029 * @parser_data: MTD partition parser-specific data
1030 * @parts: fallback partition information to register, if parsing fails;
1031 *         only valid if %nr_parts > %0
1032 * @nr_parts: the number of partitions in parts, if zero then the full
1033 *            MTD device is registered if no partition info is found
1034 *
1035 * This function aggregates MTD partitions parsing (done by
1036 * 'parse_mtd_partitions()') and MTD device and partitions registering. It
1037 * basically follows the most common pattern found in many MTD drivers:
1038 *
1039 * * If the MTD_PARTITIONED_MASTER option is set, then the device as a whole is
1040 *   registered first.
1041 * * Then It tries to probe partitions on MTD device @mtd using parsers
1042 *   specified in @types (if @types is %NULL, then the default list of parsers
1043 *   is used, see 'parse_mtd_partitions()' for more information). If none are
1044 *   found this functions tries to fallback to information specified in
1045 *   @parts/@nr_parts.
1046 * * If no partitions were found this function just registers the MTD device
1047 *   @mtd and exits.
1048 *
1049 * Returns zero in case of success and a negative error code in case of failure.
1050 */
1051int mtd_device_parse_register(struct mtd_info *mtd, const char * const *types,
1052			      struct mtd_part_parser_data *parser_data,
1053			      const struct mtd_partition *parts,
1054			      int nr_parts)
1055{
1056	int ret;
1057
1058	mtd_set_dev_defaults(mtd);
1059
1060	ret = mtd_otp_nvmem_add(mtd);
1061	if (ret)
1062		goto out;
1063
1064	if (IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER)) {
1065		ret = add_mtd_device(mtd);
1066		if (ret)
1067			goto out;
1068	}
1069
1070	/* Prefer parsed partitions over driver-provided fallback */
1071	ret = parse_mtd_partitions(mtd, types, parser_data);
1072	if (ret == -EPROBE_DEFER)
1073		goto out;
1074
1075	if (ret > 0)
1076		ret = 0;
1077	else if (nr_parts)
1078		ret = add_mtd_partitions(mtd, parts, nr_parts);
1079	else if (!device_is_registered(&mtd->dev))
1080		ret = add_mtd_device(mtd);
1081	else
1082		ret = 0;
1083
1084	if (ret)
1085		goto out;
1086
1087	/*
1088	 * FIXME: some drivers unfortunately call this function more than once.
1089	 * So we have to check if we've already assigned the reboot notifier.
1090	 *
1091	 * Generally, we can make multiple calls work for most cases, but it
1092	 * does cause problems with parse_mtd_partitions() above (e.g.,
1093	 * cmdlineparts will register partitions more than once).
1094	 */
1095	WARN_ONCE(mtd->_reboot && mtd->reboot_notifier.notifier_call,
1096		  "MTD already registered\n");
1097	if (mtd->_reboot && !mtd->reboot_notifier.notifier_call) {
1098		mtd->reboot_notifier.notifier_call = mtd_reboot_notifier;
1099		register_reboot_notifier(&mtd->reboot_notifier);
1100	}
1101
1102out:
1103	if (ret) {
1104		nvmem_unregister(mtd->otp_user_nvmem);
1105		nvmem_unregister(mtd->otp_factory_nvmem);
1106	}
1107
1108	if (ret && device_is_registered(&mtd->dev))
1109		del_mtd_device(mtd);
1110
1111	return ret;
1112}
1113EXPORT_SYMBOL_GPL(mtd_device_parse_register);
1114
1115/**
1116 * mtd_device_unregister - unregister an existing MTD device.
1117 *
1118 * @master: the MTD device to unregister.  This will unregister both the master
1119 *          and any partitions if registered.
1120 */
1121int mtd_device_unregister(struct mtd_info *master)
1122{
1123	int err;
1124
1125	if (master->_reboot) {
1126		unregister_reboot_notifier(&master->reboot_notifier);
1127		memset(&master->reboot_notifier, 0, sizeof(master->reboot_notifier));
1128	}
1129
1130	nvmem_unregister(master->otp_user_nvmem);
1131	nvmem_unregister(master->otp_factory_nvmem);
1132
1133	err = del_mtd_partitions(master);
1134	if (err)
1135		return err;
1136
1137	if (!device_is_registered(&master->dev))
1138		return 0;
1139
1140	return del_mtd_device(master);
1141}
1142EXPORT_SYMBOL_GPL(mtd_device_unregister);
1143
1144/**
1145 *	register_mtd_user - register a 'user' of MTD devices.
1146 *	@new: pointer to notifier info structure
1147 *
1148 *	Registers a pair of callbacks function to be called upon addition
1149 *	or removal of MTD devices. Causes the 'add' callback to be immediately
1150 *	invoked for each MTD device currently present in the system.
1151 */
1152void register_mtd_user (struct mtd_notifier *new)
1153{
1154	struct mtd_info *mtd;
1155
1156	mutex_lock(&mtd_table_mutex);
1157
1158	list_add(&new->list, &mtd_notifiers);
1159
1160	__module_get(THIS_MODULE);
1161
1162	mtd_for_each_device(mtd)
1163		new->add(mtd);
1164
1165	mutex_unlock(&mtd_table_mutex);
1166}
1167EXPORT_SYMBOL_GPL(register_mtd_user);
1168
1169/**
1170 *	unregister_mtd_user - unregister a 'user' of MTD devices.
1171 *	@old: pointer to notifier info structure
1172 *
1173 *	Removes a callback function pair from the list of 'users' to be
1174 *	notified upon addition or removal of MTD devices. Causes the
1175 *	'remove' callback to be immediately invoked for each MTD device
1176 *	currently present in the system.
1177 */
1178int unregister_mtd_user (struct mtd_notifier *old)
1179{
1180	struct mtd_info *mtd;
1181
1182	mutex_lock(&mtd_table_mutex);
1183
1184	module_put(THIS_MODULE);
1185
1186	mtd_for_each_device(mtd)
1187		old->remove(mtd);
1188
1189	list_del(&old->list);
1190	mutex_unlock(&mtd_table_mutex);
1191	return 0;
1192}
1193EXPORT_SYMBOL_GPL(unregister_mtd_user);
1194
1195/**
1196 *	get_mtd_device - obtain a validated handle for an MTD device
1197 *	@mtd: last known address of the required MTD device
1198 *	@num: internal device number of the required MTD device
1199 *
1200 *	Given a number and NULL address, return the num'th entry in the device
1201 *	table, if any.	Given an address and num == -1, search the device table
1202 *	for a device with that address and return if it's still present. Given
1203 *	both, return the num'th driver only if its address matches. Return
1204 *	error code if not.
1205 */
1206struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
1207{
1208	struct mtd_info *ret = NULL, *other;
1209	int err = -ENODEV;
1210
1211	mutex_lock(&mtd_table_mutex);
1212
1213	if (num == -1) {
1214		mtd_for_each_device(other) {
1215			if (other == mtd) {
1216				ret = mtd;
1217				break;
1218			}
1219		}
1220	} else if (num >= 0) {
1221		ret = idr_find(&mtd_idr, num);
1222		if (mtd && mtd != ret)
1223			ret = NULL;
1224	}
1225
1226	if (!ret) {
1227		ret = ERR_PTR(err);
1228		goto out;
1229	}
1230
1231	err = __get_mtd_device(ret);
1232	if (err)
1233		ret = ERR_PTR(err);
1234out:
1235	mutex_unlock(&mtd_table_mutex);
1236	return ret;
1237}
1238EXPORT_SYMBOL_GPL(get_mtd_device);
1239
1240
1241int __get_mtd_device(struct mtd_info *mtd)
1242{
1243	struct mtd_info *master = mtd_get_master(mtd);
1244	int err;
1245
 
 
 
1246	if (master->_get_device) {
1247		err = master->_get_device(mtd);
1248		if (err)
1249			return err;
1250	}
1251
1252	if (!try_module_get(master->owner)) {
1253		if (master->_put_device)
1254			master->_put_device(master);
1255		return -ENODEV;
1256	}
1257
1258	while (mtd) {
1259		if (mtd != master)
1260			kref_get(&mtd->refcnt);
1261		mtd = mtd->parent;
1262	}
1263
1264	if (IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER))
1265		kref_get(&master->refcnt);
1266
1267	return 0;
1268}
1269EXPORT_SYMBOL_GPL(__get_mtd_device);
1270
1271/**
1272 * of_get_mtd_device_by_node - obtain an MTD device associated with a given node
1273 *
1274 * @np: device tree node
1275 */
1276struct mtd_info *of_get_mtd_device_by_node(struct device_node *np)
1277{
1278	struct mtd_info *mtd = NULL;
1279	struct mtd_info *tmp;
1280	int err;
1281
1282	mutex_lock(&mtd_table_mutex);
1283
1284	err = -EPROBE_DEFER;
1285	mtd_for_each_device(tmp) {
1286		if (mtd_get_of_node(tmp) == np) {
1287			mtd = tmp;
1288			err = __get_mtd_device(mtd);
1289			break;
1290		}
1291	}
1292
1293	mutex_unlock(&mtd_table_mutex);
1294
1295	return err ? ERR_PTR(err) : mtd;
1296}
1297EXPORT_SYMBOL_GPL(of_get_mtd_device_by_node);
1298
1299/**
1300 *	get_mtd_device_nm - obtain a validated handle for an MTD device by
1301 *	device name
1302 *	@name: MTD device name to open
1303 *
1304 * 	This function returns MTD device description structure in case of
1305 * 	success and an error code in case of failure.
1306 */
1307struct mtd_info *get_mtd_device_nm(const char *name)
1308{
1309	int err = -ENODEV;
1310	struct mtd_info *mtd = NULL, *other;
1311
1312	mutex_lock(&mtd_table_mutex);
1313
1314	mtd_for_each_device(other) {
1315		if (!strcmp(name, other->name)) {
1316			mtd = other;
1317			break;
1318		}
1319	}
1320
1321	if (!mtd)
1322		goto out_unlock;
1323
1324	err = __get_mtd_device(mtd);
1325	if (err)
1326		goto out_unlock;
1327
1328	mutex_unlock(&mtd_table_mutex);
1329	return mtd;
1330
1331out_unlock:
1332	mutex_unlock(&mtd_table_mutex);
1333	return ERR_PTR(err);
1334}
1335EXPORT_SYMBOL_GPL(get_mtd_device_nm);
1336
1337void put_mtd_device(struct mtd_info *mtd)
1338{
1339	mutex_lock(&mtd_table_mutex);
1340	__put_mtd_device(mtd);
1341	mutex_unlock(&mtd_table_mutex);
1342
1343}
1344EXPORT_SYMBOL_GPL(put_mtd_device);
1345
1346void __put_mtd_device(struct mtd_info *mtd)
1347{
1348	struct mtd_info *master = mtd_get_master(mtd);
1349
1350	while (mtd) {
1351		/* kref_put() can relese mtd, so keep a reference mtd->parent */
1352		struct mtd_info *parent = mtd->parent;
1353
1354		if (mtd != master)
1355			kref_put(&mtd->refcnt, mtd_device_release);
1356		mtd = parent;
1357	}
1358
1359	if (IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER))
1360		kref_put(&master->refcnt, mtd_device_release);
1361
1362	module_put(master->owner);
1363
1364	/* must be the last as master can be freed in the _put_device */
1365	if (master->_put_device)
1366		master->_put_device(master);
 
 
1367}
1368EXPORT_SYMBOL_GPL(__put_mtd_device);
1369
1370/*
1371 * Erase is an synchronous operation. Device drivers are epected to return a
1372 * negative error code if the operation failed and update instr->fail_addr
1373 * to point the portion that was not properly erased.
1374 */
1375int mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
1376{
1377	struct mtd_info *master = mtd_get_master(mtd);
1378	u64 mst_ofs = mtd_get_master_ofs(mtd, 0);
1379	struct erase_info adjinstr;
1380	int ret;
1381
1382	instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
1383	adjinstr = *instr;
1384
1385	if (!mtd->erasesize || !master->_erase)
1386		return -ENOTSUPP;
1387
1388	if (instr->addr >= mtd->size || instr->len > mtd->size - instr->addr)
1389		return -EINVAL;
1390	if (!(mtd->flags & MTD_WRITEABLE))
1391		return -EROFS;
1392
1393	if (!instr->len)
1394		return 0;
1395
1396	ledtrig_mtd_activity();
1397
1398	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) {
1399		adjinstr.addr = (loff_t)mtd_div_by_eb(instr->addr, mtd) *
1400				master->erasesize;
1401		adjinstr.len = ((u64)mtd_div_by_eb(instr->addr + instr->len, mtd) *
1402				master->erasesize) -
1403			       adjinstr.addr;
1404	}
1405
1406	adjinstr.addr += mst_ofs;
1407
1408	ret = master->_erase(master, &adjinstr);
1409
1410	if (adjinstr.fail_addr != MTD_FAIL_ADDR_UNKNOWN) {
1411		instr->fail_addr = adjinstr.fail_addr - mst_ofs;
1412		if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) {
1413			instr->fail_addr = mtd_div_by_eb(instr->fail_addr,
1414							 master);
1415			instr->fail_addr *= mtd->erasesize;
1416		}
1417	}
1418
1419	return ret;
1420}
1421EXPORT_SYMBOL_GPL(mtd_erase);
1422ALLOW_ERROR_INJECTION(mtd_erase, ERRNO);
1423
1424/*
1425 * This stuff for eXecute-In-Place. phys is optional and may be set to NULL.
1426 */
1427int mtd_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
1428	      void **virt, resource_size_t *phys)
1429{
1430	struct mtd_info *master = mtd_get_master(mtd);
1431
1432	*retlen = 0;
1433	*virt = NULL;
1434	if (phys)
1435		*phys = 0;
1436	if (!master->_point)
1437		return -EOPNOTSUPP;
1438	if (from < 0 || from >= mtd->size || len > mtd->size - from)
1439		return -EINVAL;
1440	if (!len)
1441		return 0;
1442
1443	from = mtd_get_master_ofs(mtd, from);
1444	return master->_point(master, from, len, retlen, virt, phys);
1445}
1446EXPORT_SYMBOL_GPL(mtd_point);
1447
1448/* We probably shouldn't allow XIP if the unpoint isn't a NULL */
1449int mtd_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
1450{
1451	struct mtd_info *master = mtd_get_master(mtd);
1452
1453	if (!master->_unpoint)
1454		return -EOPNOTSUPP;
1455	if (from < 0 || from >= mtd->size || len > mtd->size - from)
1456		return -EINVAL;
1457	if (!len)
1458		return 0;
1459	return master->_unpoint(master, mtd_get_master_ofs(mtd, from), len);
1460}
1461EXPORT_SYMBOL_GPL(mtd_unpoint);
1462
1463/*
1464 * Allow NOMMU mmap() to directly map the device (if not NULL)
1465 * - return the address to which the offset maps
1466 * - return -ENOSYS to indicate refusal to do the mapping
1467 */
1468unsigned long mtd_get_unmapped_area(struct mtd_info *mtd, unsigned long len,
1469				    unsigned long offset, unsigned long flags)
1470{
1471	size_t retlen;
1472	void *virt;
1473	int ret;
1474
1475	ret = mtd_point(mtd, offset, len, &retlen, &virt, NULL);
1476	if (ret)
1477		return ret;
1478	if (retlen != len) {
1479		mtd_unpoint(mtd, offset, retlen);
1480		return -ENOSYS;
1481	}
1482	return (unsigned long)virt;
1483}
1484EXPORT_SYMBOL_GPL(mtd_get_unmapped_area);
1485
1486static void mtd_update_ecc_stats(struct mtd_info *mtd, struct mtd_info *master,
1487				 const struct mtd_ecc_stats *old_stats)
1488{
1489	struct mtd_ecc_stats diff;
1490
1491	if (master == mtd)
1492		return;
1493
1494	diff = master->ecc_stats;
1495	diff.failed -= old_stats->failed;
1496	diff.corrected -= old_stats->corrected;
1497
1498	while (mtd->parent) {
1499		mtd->ecc_stats.failed += diff.failed;
1500		mtd->ecc_stats.corrected += diff.corrected;
1501		mtd = mtd->parent;
1502	}
1503}
1504
1505int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
1506	     u_char *buf)
1507{
1508	struct mtd_oob_ops ops = {
1509		.len = len,
1510		.datbuf = buf,
1511	};
1512	int ret;
1513
1514	ret = mtd_read_oob(mtd, from, &ops);
1515	*retlen = ops.retlen;
1516
1517	WARN_ON_ONCE(*retlen != len && mtd_is_bitflip_or_eccerr(ret));
1518
1519	return ret;
1520}
1521EXPORT_SYMBOL_GPL(mtd_read);
1522ALLOW_ERROR_INJECTION(mtd_read, ERRNO);
1523
1524int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
1525	      const u_char *buf)
1526{
1527	struct mtd_oob_ops ops = {
1528		.len = len,
1529		.datbuf = (u8 *)buf,
1530	};
1531	int ret;
1532
1533	ret = mtd_write_oob(mtd, to, &ops);
1534	*retlen = ops.retlen;
1535
1536	return ret;
1537}
1538EXPORT_SYMBOL_GPL(mtd_write);
1539ALLOW_ERROR_INJECTION(mtd_write, ERRNO);
1540
1541/*
1542 * In blackbox flight recorder like scenarios we want to make successful writes
1543 * in interrupt context. panic_write() is only intended to be called when its
1544 * known the kernel is about to panic and we need the write to succeed. Since
1545 * the kernel is not going to be running for much longer, this function can
1546 * break locks and delay to ensure the write succeeds (but not sleep).
1547 */
1548int mtd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
1549		    const u_char *buf)
1550{
1551	struct mtd_info *master = mtd_get_master(mtd);
1552
1553	*retlen = 0;
1554	if (!master->_panic_write)
1555		return -EOPNOTSUPP;
1556	if (to < 0 || to >= mtd->size || len > mtd->size - to)
1557		return -EINVAL;
1558	if (!(mtd->flags & MTD_WRITEABLE))
1559		return -EROFS;
1560	if (!len)
1561		return 0;
1562	if (!master->oops_panic_write)
1563		master->oops_panic_write = true;
1564
1565	return master->_panic_write(master, mtd_get_master_ofs(mtd, to), len,
1566				    retlen, buf);
1567}
1568EXPORT_SYMBOL_GPL(mtd_panic_write);
1569
1570static int mtd_check_oob_ops(struct mtd_info *mtd, loff_t offs,
1571			     struct mtd_oob_ops *ops)
1572{
1573	/*
1574	 * Some users are setting ->datbuf or ->oobbuf to NULL, but are leaving
1575	 * ->len or ->ooblen uninitialized. Force ->len and ->ooblen to 0 in
1576	 *  this case.
1577	 */
1578	if (!ops->datbuf)
1579		ops->len = 0;
1580
1581	if (!ops->oobbuf)
1582		ops->ooblen = 0;
1583
1584	if (offs < 0 || offs + ops->len > mtd->size)
1585		return -EINVAL;
1586
1587	if (ops->ooblen) {
1588		size_t maxooblen;
1589
1590		if (ops->ooboffs >= mtd_oobavail(mtd, ops))
1591			return -EINVAL;
1592
1593		maxooblen = ((size_t)(mtd_div_by_ws(mtd->size, mtd) -
1594				      mtd_div_by_ws(offs, mtd)) *
1595			     mtd_oobavail(mtd, ops)) - ops->ooboffs;
1596		if (ops->ooblen > maxooblen)
1597			return -EINVAL;
1598	}
1599
1600	return 0;
1601}
1602
1603static int mtd_read_oob_std(struct mtd_info *mtd, loff_t from,
1604			    struct mtd_oob_ops *ops)
1605{
1606	struct mtd_info *master = mtd_get_master(mtd);
1607	int ret;
1608
1609	from = mtd_get_master_ofs(mtd, from);
1610	if (master->_read_oob)
1611		ret = master->_read_oob(master, from, ops);
1612	else
1613		ret = master->_read(master, from, ops->len, &ops->retlen,
1614				    ops->datbuf);
1615
1616	return ret;
1617}
1618
1619static int mtd_write_oob_std(struct mtd_info *mtd, loff_t to,
1620			     struct mtd_oob_ops *ops)
1621{
1622	struct mtd_info *master = mtd_get_master(mtd);
1623	int ret;
1624
1625	to = mtd_get_master_ofs(mtd, to);
1626	if (master->_write_oob)
1627		ret = master->_write_oob(master, to, ops);
1628	else
1629		ret = master->_write(master, to, ops->len, &ops->retlen,
1630				     ops->datbuf);
1631
1632	return ret;
1633}
1634
1635static int mtd_io_emulated_slc(struct mtd_info *mtd, loff_t start, bool read,
1636			       struct mtd_oob_ops *ops)
1637{
1638	struct mtd_info *master = mtd_get_master(mtd);
1639	int ngroups = mtd_pairing_groups(master);
1640	int npairs = mtd_wunit_per_eb(master) / ngroups;
1641	struct mtd_oob_ops adjops = *ops;
1642	unsigned int wunit, oobavail;
1643	struct mtd_pairing_info info;
1644	int max_bitflips = 0;
1645	u32 ebofs, pageofs;
1646	loff_t base, pos;
1647
1648	ebofs = mtd_mod_by_eb(start, mtd);
1649	base = (loff_t)mtd_div_by_eb(start, mtd) * master->erasesize;
1650	info.group = 0;
1651	info.pair = mtd_div_by_ws(ebofs, mtd);
1652	pageofs = mtd_mod_by_ws(ebofs, mtd);
1653	oobavail = mtd_oobavail(mtd, ops);
1654
1655	while (ops->retlen < ops->len || ops->oobretlen < ops->ooblen) {
1656		int ret;
1657
1658		if (info.pair >= npairs) {
1659			info.pair = 0;
1660			base += master->erasesize;
1661		}
1662
1663		wunit = mtd_pairing_info_to_wunit(master, &info);
1664		pos = mtd_wunit_to_offset(mtd, base, wunit);
1665
1666		adjops.len = ops->len - ops->retlen;
1667		if (adjops.len > mtd->writesize - pageofs)
1668			adjops.len = mtd->writesize - pageofs;
1669
1670		adjops.ooblen = ops->ooblen - ops->oobretlen;
1671		if (adjops.ooblen > oobavail - adjops.ooboffs)
1672			adjops.ooblen = oobavail - adjops.ooboffs;
1673
1674		if (read) {
1675			ret = mtd_read_oob_std(mtd, pos + pageofs, &adjops);
1676			if (ret > 0)
1677				max_bitflips = max(max_bitflips, ret);
1678		} else {
1679			ret = mtd_write_oob_std(mtd, pos + pageofs, &adjops);
1680		}
1681
1682		if (ret < 0)
1683			return ret;
1684
1685		max_bitflips = max(max_bitflips, ret);
1686		ops->retlen += adjops.retlen;
1687		ops->oobretlen += adjops.oobretlen;
1688		adjops.datbuf += adjops.retlen;
1689		adjops.oobbuf += adjops.oobretlen;
1690		adjops.ooboffs = 0;
1691		pageofs = 0;
1692		info.pair++;
1693	}
1694
1695	return max_bitflips;
1696}
1697
1698int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
1699{
1700	struct mtd_info *master = mtd_get_master(mtd);
1701	struct mtd_ecc_stats old_stats = master->ecc_stats;
1702	int ret_code;
1703
1704	ops->retlen = ops->oobretlen = 0;
1705
1706	ret_code = mtd_check_oob_ops(mtd, from, ops);
1707	if (ret_code)
1708		return ret_code;
1709
1710	ledtrig_mtd_activity();
1711
1712	/* Check the validity of a potential fallback on mtd->_read */
1713	if (!master->_read_oob && (!master->_read || ops->oobbuf))
1714		return -EOPNOTSUPP;
1715
1716	if (ops->stats)
1717		memset(ops->stats, 0, sizeof(*ops->stats));
1718
1719	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
1720		ret_code = mtd_io_emulated_slc(mtd, from, true, ops);
1721	else
1722		ret_code = mtd_read_oob_std(mtd, from, ops);
1723
1724	mtd_update_ecc_stats(mtd, master, &old_stats);
1725
1726	/*
1727	 * In cases where ops->datbuf != NULL, mtd->_read_oob() has semantics
1728	 * similar to mtd->_read(), returning a non-negative integer
1729	 * representing max bitflips. In other cases, mtd->_read_oob() may
1730	 * return -EUCLEAN. In all cases, perform similar logic to mtd_read().
1731	 */
1732	if (unlikely(ret_code < 0))
1733		return ret_code;
1734	if (mtd->ecc_strength == 0)
1735		return 0;	/* device lacks ecc */
1736	if (ops->stats)
1737		ops->stats->max_bitflips = ret_code;
1738	return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
1739}
1740EXPORT_SYMBOL_GPL(mtd_read_oob);
1741
1742int mtd_write_oob(struct mtd_info *mtd, loff_t to,
1743				struct mtd_oob_ops *ops)
1744{
1745	struct mtd_info *master = mtd_get_master(mtd);
1746	int ret;
1747
1748	ops->retlen = ops->oobretlen = 0;
1749
1750	if (!(mtd->flags & MTD_WRITEABLE))
1751		return -EROFS;
1752
1753	ret = mtd_check_oob_ops(mtd, to, ops);
1754	if (ret)
1755		return ret;
1756
1757	ledtrig_mtd_activity();
1758
1759	/* Check the validity of a potential fallback on mtd->_write */
1760	if (!master->_write_oob && (!master->_write || ops->oobbuf))
1761		return -EOPNOTSUPP;
1762
1763	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
1764		return mtd_io_emulated_slc(mtd, to, false, ops);
1765
1766	return mtd_write_oob_std(mtd, to, ops);
1767}
1768EXPORT_SYMBOL_GPL(mtd_write_oob);
1769
1770/**
1771 * mtd_ooblayout_ecc - Get the OOB region definition of a specific ECC section
1772 * @mtd: MTD device structure
1773 * @section: ECC section. Depending on the layout you may have all the ECC
1774 *	     bytes stored in a single contiguous section, or one section
1775 *	     per ECC chunk (and sometime several sections for a single ECC
1776 *	     ECC chunk)
1777 * @oobecc: OOB region struct filled with the appropriate ECC position
1778 *	    information
1779 *
1780 * This function returns ECC section information in the OOB area. If you want
1781 * to get all the ECC bytes information, then you should call
1782 * mtd_ooblayout_ecc(mtd, section++, oobecc) until it returns -ERANGE.
1783 *
1784 * Returns zero on success, a negative error code otherwise.
1785 */
1786int mtd_ooblayout_ecc(struct mtd_info *mtd, int section,
1787		      struct mtd_oob_region *oobecc)
1788{
1789	struct mtd_info *master = mtd_get_master(mtd);
1790
1791	memset(oobecc, 0, sizeof(*oobecc));
1792
1793	if (!master || section < 0)
1794		return -EINVAL;
1795
1796	if (!master->ooblayout || !master->ooblayout->ecc)
1797		return -ENOTSUPP;
1798
1799	return master->ooblayout->ecc(master, section, oobecc);
1800}
1801EXPORT_SYMBOL_GPL(mtd_ooblayout_ecc);
1802
1803/**
1804 * mtd_ooblayout_free - Get the OOB region definition of a specific free
1805 *			section
1806 * @mtd: MTD device structure
1807 * @section: Free section you are interested in. Depending on the layout
1808 *	     you may have all the free bytes stored in a single contiguous
1809 *	     section, or one section per ECC chunk plus an extra section
1810 *	     for the remaining bytes (or other funky layout).
1811 * @oobfree: OOB region struct filled with the appropriate free position
1812 *	     information
1813 *
1814 * This function returns free bytes position in the OOB area. If you want
1815 * to get all the free bytes information, then you should call
1816 * mtd_ooblayout_free(mtd, section++, oobfree) until it returns -ERANGE.
1817 *
1818 * Returns zero on success, a negative error code otherwise.
1819 */
1820int mtd_ooblayout_free(struct mtd_info *mtd, int section,
1821		       struct mtd_oob_region *oobfree)
1822{
1823	struct mtd_info *master = mtd_get_master(mtd);
1824
1825	memset(oobfree, 0, sizeof(*oobfree));
1826
1827	if (!master || section < 0)
1828		return -EINVAL;
1829
1830	if (!master->ooblayout || !master->ooblayout->free)
1831		return -ENOTSUPP;
1832
1833	return master->ooblayout->free(master, section, oobfree);
1834}
1835EXPORT_SYMBOL_GPL(mtd_ooblayout_free);
1836
1837/**
1838 * mtd_ooblayout_find_region - Find the region attached to a specific byte
1839 * @mtd: mtd info structure
1840 * @byte: the byte we are searching for
1841 * @sectionp: pointer where the section id will be stored
1842 * @oobregion: used to retrieve the ECC position
1843 * @iter: iterator function. Should be either mtd_ooblayout_free or
1844 *	  mtd_ooblayout_ecc depending on the region type you're searching for
1845 *
1846 * This function returns the section id and oobregion information of a
1847 * specific byte. For example, say you want to know where the 4th ECC byte is
1848 * stored, you'll use:
1849 *
1850 * mtd_ooblayout_find_region(mtd, 3, &section, &oobregion, mtd_ooblayout_ecc);
1851 *
1852 * Returns zero on success, a negative error code otherwise.
1853 */
1854static int mtd_ooblayout_find_region(struct mtd_info *mtd, int byte,
1855				int *sectionp, struct mtd_oob_region *oobregion,
1856				int (*iter)(struct mtd_info *,
1857					    int section,
1858					    struct mtd_oob_region *oobregion))
1859{
1860	int pos = 0, ret, section = 0;
1861
1862	memset(oobregion, 0, sizeof(*oobregion));
1863
1864	while (1) {
1865		ret = iter(mtd, section, oobregion);
1866		if (ret)
1867			return ret;
1868
1869		if (pos + oobregion->length > byte)
1870			break;
1871
1872		pos += oobregion->length;
1873		section++;
1874	}
1875
1876	/*
1877	 * Adjust region info to make it start at the beginning at the
1878	 * 'start' ECC byte.
1879	 */
1880	oobregion->offset += byte - pos;
1881	oobregion->length -= byte - pos;
1882	*sectionp = section;
1883
1884	return 0;
1885}
1886
1887/**
1888 * mtd_ooblayout_find_eccregion - Find the ECC region attached to a specific
1889 *				  ECC byte
1890 * @mtd: mtd info structure
1891 * @eccbyte: the byte we are searching for
1892 * @section: pointer where the section id will be stored
1893 * @oobregion: OOB region information
1894 *
1895 * Works like mtd_ooblayout_find_region() except it searches for a specific ECC
1896 * byte.
1897 *
1898 * Returns zero on success, a negative error code otherwise.
1899 */
1900int mtd_ooblayout_find_eccregion(struct mtd_info *mtd, int eccbyte,
1901				 int *section,
1902				 struct mtd_oob_region *oobregion)
1903{
1904	return mtd_ooblayout_find_region(mtd, eccbyte, section, oobregion,
1905					 mtd_ooblayout_ecc);
1906}
1907EXPORT_SYMBOL_GPL(mtd_ooblayout_find_eccregion);
1908
1909/**
1910 * mtd_ooblayout_get_bytes - Extract OOB bytes from the oob buffer
1911 * @mtd: mtd info structure
1912 * @buf: destination buffer to store OOB bytes
1913 * @oobbuf: OOB buffer
1914 * @start: first byte to retrieve
1915 * @nbytes: number of bytes to retrieve
1916 * @iter: section iterator
1917 *
1918 * Extract bytes attached to a specific category (ECC or free)
1919 * from the OOB buffer and copy them into buf.
1920 *
1921 * Returns zero on success, a negative error code otherwise.
1922 */
1923static int mtd_ooblayout_get_bytes(struct mtd_info *mtd, u8 *buf,
1924				const u8 *oobbuf, int start, int nbytes,
1925				int (*iter)(struct mtd_info *,
1926					    int section,
1927					    struct mtd_oob_region *oobregion))
1928{
1929	struct mtd_oob_region oobregion;
1930	int section, ret;
1931
1932	ret = mtd_ooblayout_find_region(mtd, start, &section,
1933					&oobregion, iter);
1934
1935	while (!ret) {
1936		int cnt;
1937
1938		cnt = min_t(int, nbytes, oobregion.length);
1939		memcpy(buf, oobbuf + oobregion.offset, cnt);
1940		buf += cnt;
1941		nbytes -= cnt;
1942
1943		if (!nbytes)
1944			break;
1945
1946		ret = iter(mtd, ++section, &oobregion);
1947	}
1948
1949	return ret;
1950}
1951
1952/**
1953 * mtd_ooblayout_set_bytes - put OOB bytes into the oob buffer
1954 * @mtd: mtd info structure
1955 * @buf: source buffer to get OOB bytes from
1956 * @oobbuf: OOB buffer
1957 * @start: first OOB byte to set
1958 * @nbytes: number of OOB bytes to set
1959 * @iter: section iterator
1960 *
1961 * Fill the OOB buffer with data provided in buf. The category (ECC or free)
1962 * is selected by passing the appropriate iterator.
1963 *
1964 * Returns zero on success, a negative error code otherwise.
1965 */
1966static int mtd_ooblayout_set_bytes(struct mtd_info *mtd, const u8 *buf,
1967				u8 *oobbuf, int start, int nbytes,
1968				int (*iter)(struct mtd_info *,
1969					    int section,
1970					    struct mtd_oob_region *oobregion))
1971{
1972	struct mtd_oob_region oobregion;
1973	int section, ret;
1974
1975	ret = mtd_ooblayout_find_region(mtd, start, &section,
1976					&oobregion, iter);
1977
1978	while (!ret) {
1979		int cnt;
1980
1981		cnt = min_t(int, nbytes, oobregion.length);
1982		memcpy(oobbuf + oobregion.offset, buf, cnt);
1983		buf += cnt;
1984		nbytes -= cnt;
1985
1986		if (!nbytes)
1987			break;
1988
1989		ret = iter(mtd, ++section, &oobregion);
1990	}
1991
1992	return ret;
1993}
1994
1995/**
1996 * mtd_ooblayout_count_bytes - count the number of bytes in a OOB category
1997 * @mtd: mtd info structure
1998 * @iter: category iterator
1999 *
2000 * Count the number of bytes in a given category.
2001 *
2002 * Returns a positive value on success, a negative error code otherwise.
2003 */
2004static int mtd_ooblayout_count_bytes(struct mtd_info *mtd,
2005				int (*iter)(struct mtd_info *,
2006					    int section,
2007					    struct mtd_oob_region *oobregion))
2008{
2009	struct mtd_oob_region oobregion;
2010	int section = 0, ret, nbytes = 0;
2011
2012	while (1) {
2013		ret = iter(mtd, section++, &oobregion);
2014		if (ret) {
2015			if (ret == -ERANGE)
2016				ret = nbytes;
2017			break;
2018		}
2019
2020		nbytes += oobregion.length;
2021	}
2022
2023	return ret;
2024}
2025
2026/**
2027 * mtd_ooblayout_get_eccbytes - extract ECC bytes from the oob buffer
2028 * @mtd: mtd info structure
2029 * @eccbuf: destination buffer to store ECC bytes
2030 * @oobbuf: OOB buffer
2031 * @start: first ECC byte to retrieve
2032 * @nbytes: number of ECC bytes to retrieve
2033 *
2034 * Works like mtd_ooblayout_get_bytes(), except it acts on ECC bytes.
2035 *
2036 * Returns zero on success, a negative error code otherwise.
2037 */
2038int mtd_ooblayout_get_eccbytes(struct mtd_info *mtd, u8 *eccbuf,
2039			       const u8 *oobbuf, int start, int nbytes)
2040{
2041	return mtd_ooblayout_get_bytes(mtd, eccbuf, oobbuf, start, nbytes,
2042				       mtd_ooblayout_ecc);
2043}
2044EXPORT_SYMBOL_GPL(mtd_ooblayout_get_eccbytes);
2045
2046/**
2047 * mtd_ooblayout_set_eccbytes - set ECC bytes into the oob buffer
2048 * @mtd: mtd info structure
2049 * @eccbuf: source buffer to get ECC bytes from
2050 * @oobbuf: OOB buffer
2051 * @start: first ECC byte to set
2052 * @nbytes: number of ECC bytes to set
2053 *
2054 * Works like mtd_ooblayout_set_bytes(), except it acts on ECC bytes.
2055 *
2056 * Returns zero on success, a negative error code otherwise.
2057 */
2058int mtd_ooblayout_set_eccbytes(struct mtd_info *mtd, const u8 *eccbuf,
2059			       u8 *oobbuf, int start, int nbytes)
2060{
2061	return mtd_ooblayout_set_bytes(mtd, eccbuf, oobbuf, start, nbytes,
2062				       mtd_ooblayout_ecc);
2063}
2064EXPORT_SYMBOL_GPL(mtd_ooblayout_set_eccbytes);
2065
2066/**
2067 * mtd_ooblayout_get_databytes - extract data bytes from the oob buffer
2068 * @mtd: mtd info structure
2069 * @databuf: destination buffer to store ECC bytes
2070 * @oobbuf: OOB buffer
2071 * @start: first ECC byte to retrieve
2072 * @nbytes: number of ECC bytes to retrieve
2073 *
2074 * Works like mtd_ooblayout_get_bytes(), except it acts on free bytes.
2075 *
2076 * Returns zero on success, a negative error code otherwise.
2077 */
2078int mtd_ooblayout_get_databytes(struct mtd_info *mtd, u8 *databuf,
2079				const u8 *oobbuf, int start, int nbytes)
2080{
2081	return mtd_ooblayout_get_bytes(mtd, databuf, oobbuf, start, nbytes,
2082				       mtd_ooblayout_free);
2083}
2084EXPORT_SYMBOL_GPL(mtd_ooblayout_get_databytes);
2085
2086/**
2087 * mtd_ooblayout_set_databytes - set data bytes into the oob buffer
2088 * @mtd: mtd info structure
2089 * @databuf: source buffer to get data bytes from
2090 * @oobbuf: OOB buffer
2091 * @start: first ECC byte to set
2092 * @nbytes: number of ECC bytes to set
2093 *
2094 * Works like mtd_ooblayout_set_bytes(), except it acts on free bytes.
2095 *
2096 * Returns zero on success, a negative error code otherwise.
2097 */
2098int mtd_ooblayout_set_databytes(struct mtd_info *mtd, const u8 *databuf,
2099				u8 *oobbuf, int start, int nbytes)
2100{
2101	return mtd_ooblayout_set_bytes(mtd, databuf, oobbuf, start, nbytes,
2102				       mtd_ooblayout_free);
2103}
2104EXPORT_SYMBOL_GPL(mtd_ooblayout_set_databytes);
2105
2106/**
2107 * mtd_ooblayout_count_freebytes - count the number of free bytes in OOB
2108 * @mtd: mtd info structure
2109 *
2110 * Works like mtd_ooblayout_count_bytes(), except it count free bytes.
2111 *
2112 * Returns zero on success, a negative error code otherwise.
2113 */
2114int mtd_ooblayout_count_freebytes(struct mtd_info *mtd)
2115{
2116	return mtd_ooblayout_count_bytes(mtd, mtd_ooblayout_free);
2117}
2118EXPORT_SYMBOL_GPL(mtd_ooblayout_count_freebytes);
2119
2120/**
2121 * mtd_ooblayout_count_eccbytes - count the number of ECC bytes in OOB
2122 * @mtd: mtd info structure
2123 *
2124 * Works like mtd_ooblayout_count_bytes(), except it count ECC bytes.
2125 *
2126 * Returns zero on success, a negative error code otherwise.
2127 */
2128int mtd_ooblayout_count_eccbytes(struct mtd_info *mtd)
2129{
2130	return mtd_ooblayout_count_bytes(mtd, mtd_ooblayout_ecc);
2131}
2132EXPORT_SYMBOL_GPL(mtd_ooblayout_count_eccbytes);
2133
2134/*
2135 * Method to access the protection register area, present in some flash
2136 * devices. The user data is one time programmable but the factory data is read
2137 * only.
2138 */
2139int mtd_get_fact_prot_info(struct mtd_info *mtd, size_t len, size_t *retlen,
2140			   struct otp_info *buf)
2141{
2142	struct mtd_info *master = mtd_get_master(mtd);
2143
2144	if (!master->_get_fact_prot_info)
2145		return -EOPNOTSUPP;
2146	if (!len)
2147		return 0;
2148	return master->_get_fact_prot_info(master, len, retlen, buf);
2149}
2150EXPORT_SYMBOL_GPL(mtd_get_fact_prot_info);
2151
2152int mtd_read_fact_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
2153			   size_t *retlen, u_char *buf)
2154{
2155	struct mtd_info *master = mtd_get_master(mtd);
2156
2157	*retlen = 0;
2158	if (!master->_read_fact_prot_reg)
2159		return -EOPNOTSUPP;
2160	if (!len)
2161		return 0;
2162	return master->_read_fact_prot_reg(master, from, len, retlen, buf);
2163}
2164EXPORT_SYMBOL_GPL(mtd_read_fact_prot_reg);
2165
2166int mtd_get_user_prot_info(struct mtd_info *mtd, size_t len, size_t *retlen,
2167			   struct otp_info *buf)
2168{
2169	struct mtd_info *master = mtd_get_master(mtd);
2170
2171	if (!master->_get_user_prot_info)
2172		return -EOPNOTSUPP;
2173	if (!len)
2174		return 0;
2175	return master->_get_user_prot_info(master, len, retlen, buf);
2176}
2177EXPORT_SYMBOL_GPL(mtd_get_user_prot_info);
2178
2179int mtd_read_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
2180			   size_t *retlen, u_char *buf)
2181{
2182	struct mtd_info *master = mtd_get_master(mtd);
2183
2184	*retlen = 0;
2185	if (!master->_read_user_prot_reg)
2186		return -EOPNOTSUPP;
2187	if (!len)
2188		return 0;
2189	return master->_read_user_prot_reg(master, from, len, retlen, buf);
2190}
2191EXPORT_SYMBOL_GPL(mtd_read_user_prot_reg);
2192
2193int mtd_write_user_prot_reg(struct mtd_info *mtd, loff_t to, size_t len,
2194			    size_t *retlen, const u_char *buf)
2195{
2196	struct mtd_info *master = mtd_get_master(mtd);
2197	int ret;
2198
2199	*retlen = 0;
2200	if (!master->_write_user_prot_reg)
2201		return -EOPNOTSUPP;
2202	if (!len)
2203		return 0;
2204	ret = master->_write_user_prot_reg(master, to, len, retlen, buf);
2205	if (ret)
2206		return ret;
2207
2208	/*
2209	 * If no data could be written at all, we are out of memory and
2210	 * must return -ENOSPC.
2211	 */
2212	return (*retlen) ? 0 : -ENOSPC;
2213}
2214EXPORT_SYMBOL_GPL(mtd_write_user_prot_reg);
2215
2216int mtd_lock_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len)
2217{
2218	struct mtd_info *master = mtd_get_master(mtd);
2219
2220	if (!master->_lock_user_prot_reg)
2221		return -EOPNOTSUPP;
2222	if (!len)
2223		return 0;
2224	return master->_lock_user_prot_reg(master, from, len);
2225}
2226EXPORT_SYMBOL_GPL(mtd_lock_user_prot_reg);
2227
2228int mtd_erase_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len)
2229{
2230	struct mtd_info *master = mtd_get_master(mtd);
2231
2232	if (!master->_erase_user_prot_reg)
2233		return -EOPNOTSUPP;
2234	if (!len)
2235		return 0;
2236	return master->_erase_user_prot_reg(master, from, len);
2237}
2238EXPORT_SYMBOL_GPL(mtd_erase_user_prot_reg);
2239
2240/* Chip-supported device locking */
2241int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
2242{
2243	struct mtd_info *master = mtd_get_master(mtd);
2244
2245	if (!master->_lock)
2246		return -EOPNOTSUPP;
2247	if (ofs < 0 || ofs >= mtd->size || len > mtd->size - ofs)
2248		return -EINVAL;
2249	if (!len)
2250		return 0;
2251
2252	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) {
2253		ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize;
2254		len = (u64)mtd_div_by_eb(len, mtd) * master->erasesize;
2255	}
2256
2257	return master->_lock(master, mtd_get_master_ofs(mtd, ofs), len);
2258}
2259EXPORT_SYMBOL_GPL(mtd_lock);
2260
2261int mtd_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
2262{
2263	struct mtd_info *master = mtd_get_master(mtd);
2264
2265	if (!master->_unlock)
2266		return -EOPNOTSUPP;
2267	if (ofs < 0 || ofs >= mtd->size || len > mtd->size - ofs)
2268		return -EINVAL;
2269	if (!len)
2270		return 0;
2271
2272	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) {
2273		ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize;
2274		len = (u64)mtd_div_by_eb(len, mtd) * master->erasesize;
2275	}
2276
2277	return master->_unlock(master, mtd_get_master_ofs(mtd, ofs), len);
2278}
2279EXPORT_SYMBOL_GPL(mtd_unlock);
2280
2281int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
2282{
2283	struct mtd_info *master = mtd_get_master(mtd);
2284
2285	if (!master->_is_locked)
2286		return -EOPNOTSUPP;
2287	if (ofs < 0 || ofs >= mtd->size || len > mtd->size - ofs)
2288		return -EINVAL;
2289	if (!len)
2290		return 0;
2291
2292	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) {
2293		ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize;
2294		len = (u64)mtd_div_by_eb(len, mtd) * master->erasesize;
2295	}
2296
2297	return master->_is_locked(master, mtd_get_master_ofs(mtd, ofs), len);
2298}
2299EXPORT_SYMBOL_GPL(mtd_is_locked);
2300
2301int mtd_block_isreserved(struct mtd_info *mtd, loff_t ofs)
2302{
2303	struct mtd_info *master = mtd_get_master(mtd);
2304
2305	if (ofs < 0 || ofs >= mtd->size)
2306		return -EINVAL;
2307	if (!master->_block_isreserved)
2308		return 0;
2309
2310	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
2311		ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize;
2312
2313	return master->_block_isreserved(master, mtd_get_master_ofs(mtd, ofs));
2314}
2315EXPORT_SYMBOL_GPL(mtd_block_isreserved);
2316
2317int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs)
2318{
2319	struct mtd_info *master = mtd_get_master(mtd);
2320
2321	if (ofs < 0 || ofs >= mtd->size)
2322		return -EINVAL;
2323	if (!master->_block_isbad)
2324		return 0;
2325
2326	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
2327		ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize;
2328
2329	return master->_block_isbad(master, mtd_get_master_ofs(mtd, ofs));
2330}
2331EXPORT_SYMBOL_GPL(mtd_block_isbad);
2332
2333int mtd_block_markbad(struct mtd_info *mtd, loff_t ofs)
2334{
2335	struct mtd_info *master = mtd_get_master(mtd);
2336	int ret;
2337
2338	if (!master->_block_markbad)
2339		return -EOPNOTSUPP;
2340	if (ofs < 0 || ofs >= mtd->size)
2341		return -EINVAL;
2342	if (!(mtd->flags & MTD_WRITEABLE))
2343		return -EROFS;
2344
2345	if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
2346		ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize;
2347
2348	ret = master->_block_markbad(master, mtd_get_master_ofs(mtd, ofs));
2349	if (ret)
2350		return ret;
2351
2352	while (mtd->parent) {
2353		mtd->ecc_stats.badblocks++;
2354		mtd = mtd->parent;
2355	}
2356
2357	return 0;
2358}
2359EXPORT_SYMBOL_GPL(mtd_block_markbad);
2360ALLOW_ERROR_INJECTION(mtd_block_markbad, ERRNO);
2361
2362/*
2363 * default_mtd_writev - the default writev method
2364 * @mtd: mtd device description object pointer
2365 * @vecs: the vectors to write
2366 * @count: count of vectors in @vecs
2367 * @to: the MTD device offset to write to
2368 * @retlen: on exit contains the count of bytes written to the MTD device.
2369 *
2370 * This function returns zero in case of success and a negative error code in
2371 * case of failure.
2372 */
2373static int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
2374			      unsigned long count, loff_t to, size_t *retlen)
2375{
2376	unsigned long i;
2377	size_t totlen = 0, thislen;
2378	int ret = 0;
2379
2380	for (i = 0; i < count; i++) {
2381		if (!vecs[i].iov_len)
2382			continue;
2383		ret = mtd_write(mtd, to, vecs[i].iov_len, &thislen,
2384				vecs[i].iov_base);
2385		totlen += thislen;
2386		if (ret || thislen != vecs[i].iov_len)
2387			break;
2388		to += vecs[i].iov_len;
2389	}
2390	*retlen = totlen;
2391	return ret;
2392}
2393
2394/*
2395 * mtd_writev - the vector-based MTD write method
2396 * @mtd: mtd device description object pointer
2397 * @vecs: the vectors to write
2398 * @count: count of vectors in @vecs
2399 * @to: the MTD device offset to write to
2400 * @retlen: on exit contains the count of bytes written to the MTD device.
2401 *
2402 * This function returns zero in case of success and a negative error code in
2403 * case of failure.
2404 */
2405int mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
2406	       unsigned long count, loff_t to, size_t *retlen)
2407{
2408	struct mtd_info *master = mtd_get_master(mtd);
2409
2410	*retlen = 0;
2411	if (!(mtd->flags & MTD_WRITEABLE))
2412		return -EROFS;
2413
2414	if (!master->_writev)
2415		return default_mtd_writev(mtd, vecs, count, to, retlen);
2416
2417	return master->_writev(master, vecs, count,
2418			       mtd_get_master_ofs(mtd, to), retlen);
2419}
2420EXPORT_SYMBOL_GPL(mtd_writev);
2421
2422/**
2423 * mtd_kmalloc_up_to - allocate a contiguous buffer up to the specified size
2424 * @mtd: mtd device description object pointer
2425 * @size: a pointer to the ideal or maximum size of the allocation, points
2426 *        to the actual allocation size on success.
2427 *
2428 * This routine attempts to allocate a contiguous kernel buffer up to
2429 * the specified size, backing off the size of the request exponentially
2430 * until the request succeeds or until the allocation size falls below
2431 * the system page size. This attempts to make sure it does not adversely
2432 * impact system performance, so when allocating more than one page, we
2433 * ask the memory allocator to avoid re-trying, swapping, writing back
2434 * or performing I/O.
2435 *
2436 * Note, this function also makes sure that the allocated buffer is aligned to
2437 * the MTD device's min. I/O unit, i.e. the "mtd->writesize" value.
2438 *
2439 * This is called, for example by mtd_{read,write} and jffs2_scan_medium,
2440 * to handle smaller (i.e. degraded) buffer allocations under low- or
2441 * fragmented-memory situations where such reduced allocations, from a
2442 * requested ideal, are allowed.
2443 *
2444 * Returns a pointer to the allocated buffer on success; otherwise, NULL.
2445 */
2446void *mtd_kmalloc_up_to(const struct mtd_info *mtd, size_t *size)
2447{
2448	gfp_t flags = __GFP_NOWARN | __GFP_DIRECT_RECLAIM | __GFP_NORETRY;
2449	size_t min_alloc = max_t(size_t, mtd->writesize, PAGE_SIZE);
2450	void *kbuf;
2451
2452	*size = min_t(size_t, *size, KMALLOC_MAX_SIZE);
2453
2454	while (*size > min_alloc) {
2455		kbuf = kmalloc(*size, flags);
2456		if (kbuf)
2457			return kbuf;
2458
2459		*size >>= 1;
2460		*size = ALIGN(*size, mtd->writesize);
2461	}
2462
2463	/*
2464	 * For the last resort allocation allow 'kmalloc()' to do all sorts of
2465	 * things (write-back, dropping caches, etc) by using GFP_KERNEL.
2466	 */
2467	return kmalloc(*size, GFP_KERNEL);
2468}
2469EXPORT_SYMBOL_GPL(mtd_kmalloc_up_to);
2470
2471#ifdef CONFIG_PROC_FS
2472
2473/*====================================================================*/
2474/* Support for /proc/mtd */
2475
2476static int mtd_proc_show(struct seq_file *m, void *v)
2477{
2478	struct mtd_info *mtd;
2479
2480	seq_puts(m, "dev:    size   erasesize  name\n");
2481	mutex_lock(&mtd_table_mutex);
2482	mtd_for_each_device(mtd) {
2483		seq_printf(m, "mtd%d: %8.8llx %8.8x \"%s\"\n",
2484			   mtd->index, (unsigned long long)mtd->size,
2485			   mtd->erasesize, mtd->name);
2486	}
2487	mutex_unlock(&mtd_table_mutex);
2488	return 0;
2489}
2490#endif /* CONFIG_PROC_FS */
2491
2492/*====================================================================*/
2493/* Init code */
2494
2495static struct backing_dev_info * __init mtd_bdi_init(const char *name)
2496{
2497	struct backing_dev_info *bdi;
2498	int ret;
2499
2500	bdi = bdi_alloc(NUMA_NO_NODE);
2501	if (!bdi)
2502		return ERR_PTR(-ENOMEM);
2503	bdi->ra_pages = 0;
2504	bdi->io_pages = 0;
2505
2506	/*
2507	 * We put '-0' suffix to the name to get the same name format as we
2508	 * used to get. Since this is called only once, we get a unique name. 
2509	 */
2510	ret = bdi_register(bdi, "%.28s-0", name);
2511	if (ret)
2512		bdi_put(bdi);
2513
2514	return ret ? ERR_PTR(ret) : bdi;
2515}
2516
2517static struct proc_dir_entry *proc_mtd;
2518
2519static int __init init_mtd(void)
2520{
2521	int ret;
2522
2523	ret = class_register(&mtd_class);
2524	if (ret)
2525		goto err_reg;
2526
2527	mtd_bdi = mtd_bdi_init("mtd");
2528	if (IS_ERR(mtd_bdi)) {
2529		ret = PTR_ERR(mtd_bdi);
2530		goto err_bdi;
2531	}
2532
2533	proc_mtd = proc_create_single("mtd", 0, NULL, mtd_proc_show);
2534
2535	ret = init_mtdchar();
2536	if (ret)
2537		goto out_procfs;
2538
2539	dfs_dir_mtd = debugfs_create_dir("mtd", NULL);
2540	debugfs_create_bool("expert_analysis_mode", 0600, dfs_dir_mtd,
2541			    &mtd_expert_analysis_mode);
2542
2543	return 0;
2544
2545out_procfs:
2546	if (proc_mtd)
2547		remove_proc_entry("mtd", NULL);
2548	bdi_unregister(mtd_bdi);
2549	bdi_put(mtd_bdi);
2550err_bdi:
2551	class_unregister(&mtd_class);
2552err_reg:
2553	pr_err("Error registering mtd class or bdi: %d\n", ret);
2554	return ret;
2555}
2556
2557static void __exit cleanup_mtd(void)
2558{
2559	debugfs_remove_recursive(dfs_dir_mtd);
2560	cleanup_mtdchar();
2561	if (proc_mtd)
2562		remove_proc_entry("mtd", NULL);
2563	class_unregister(&mtd_class);
2564	bdi_unregister(mtd_bdi);
2565	bdi_put(mtd_bdi);
2566	idr_destroy(&mtd_idr);
2567}
2568
2569module_init(init_mtd);
2570module_exit(cleanup_mtd);
2571
2572MODULE_LICENSE("GPL");
2573MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
2574MODULE_DESCRIPTION("Core MTD registration and access routines");