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