mtdcore.c 19.2 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1 2 3 4
/*
 * Core registration and callback routines for MTD
 * drivers and users.
 *
5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
 * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
 * Copyright © 2006      Red Hat UK Limited 
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
Linus Torvalds's avatar
Linus Torvalds committed
22 23 24 25 26
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/ptrace.h>
27
#include <linux/seq_file.h>
Linus Torvalds's avatar
Linus Torvalds committed
28 29 30 31
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/major.h>
#include <linux/fs.h>
32
#include <linux/err.h>
Linus Torvalds's avatar
Linus Torvalds committed
33 34 35
#include <linux/ioctl.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
36
#include <linux/idr.h>
37
#include <linux/backing-dev.h>
Tejun Heo's avatar
Tejun Heo committed
38
#include <linux/gfp.h>
Linus Torvalds's avatar
Linus Torvalds committed
39 40 41

#include <linux/mtd/mtd.h>

42
#include "mtdcore.h"
43 44 45 46
/*
 * backing device capabilities for non-mappable devices (such as NAND flash)
 * - permits private mappings, copies are taken of the data
 */
47
static struct backing_dev_info mtd_bdi_unmappable = {
48 49 50 51 52 53 54 55
	.capabilities	= BDI_CAP_MAP_COPY,
};

/*
 * backing device capabilities for R/O mappable devices (such as ROM)
 * - permits private mappings, copies are taken of the data
 * - permits non-writable shared mappings
 */
56
static struct backing_dev_info mtd_bdi_ro_mappable = {
57 58 59 60 61 62 63 64 65
	.capabilities	= (BDI_CAP_MAP_COPY | BDI_CAP_MAP_DIRECT |
			   BDI_CAP_EXEC_MAP | BDI_CAP_READ_MAP),
};

/*
 * backing device capabilities for writable mappable devices (such as RAM)
 * - permits private mappings, copies are taken of the data
 * - permits non-writable shared mappings
 */
66
static struct backing_dev_info mtd_bdi_rw_mappable = {
67 68 69 70
	.capabilities	= (BDI_CAP_MAP_COPY | BDI_CAP_MAP_DIRECT |
			   BDI_CAP_EXEC_MAP | BDI_CAP_READ_MAP |
			   BDI_CAP_WRITE_MAP),
};
71

72 73 74 75 76 77 78 79 80
static int mtd_cls_suspend(struct device *dev, pm_message_t state);
static int mtd_cls_resume(struct device *dev);

static struct class mtd_class = {
	.name = "mtd",
	.owner = THIS_MODULE,
	.suspend = mtd_cls_suspend,
	.resume = mtd_cls_resume,
};
David Brownell's avatar
David Brownell committed
81

82 83
static DEFINE_IDR(mtd_idr);

84
/* These are exported solely for the purpose of mtd_blkdevs.c. You
Linus Torvalds's avatar
Linus Torvalds committed
85
   should not use them for _anything_ else */
Ingo Molnar's avatar
Ingo Molnar committed
86
DEFINE_MUTEX(mtd_table_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
87
EXPORT_SYMBOL_GPL(mtd_table_mutex);
88 89 90 91 92 93

struct mtd_info *__mtd_next_device(int i)
{
	return idr_get_next(&mtd_idr, &i);
}
EXPORT_SYMBOL_GPL(__mtd_next_device);
Linus Torvalds's avatar
Linus Torvalds committed
94 95 96

static LIST_HEAD(mtd_notifiers);

David Brownell's avatar
David Brownell committed
97 98 99 100 101 102 103 104 105 106 107 108

#if defined(CONFIG_MTD_CHAR) || defined(CONFIG_MTD_CHAR_MODULE)
#define MTD_DEVT(index) MKDEV(MTD_CHAR_MAJOR, (index)*2)
#else
#define MTD_DEVT(index) 0
#endif

/* REVISIT once MTD uses the driver model better, whoever allocates
 * the mtd_info will probably want to use the release() hook...
 */
static void mtd_release(struct device *dev)
{
109
	dev_t index = MTD_DEVT(dev_to_mtd(dev)->index);
David Brownell's avatar
David Brownell committed
110 111

	/* remove /dev/mtdXro node if needed */
112
	if (index)
113 114 115 116 117 118
		device_destroy(&mtd_class, index + 1);
}

static int mtd_cls_suspend(struct device *dev, pm_message_t state)
{
	struct mtd_info *mtd = dev_to_mtd(dev);
119 120

	if (mtd && mtd->suspend)
121 122 123 124 125 126 127 128 129
		return mtd->suspend(mtd);
	else
		return 0;
}

static int mtd_cls_resume(struct device *dev)
{
	struct mtd_info *mtd = dev_to_mtd(dev);
	
130
	if (mtd && mtd->resume)
131 132
		mtd->resume(mtd);
	return 0;
David Brownell's avatar
David Brownell committed
133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168
}

static ssize_t mtd_type_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_to_mtd(dev);
	char *type;

	switch (mtd->type) {
	case MTD_ABSENT:
		type = "absent";
		break;
	case MTD_RAM:
		type = "ram";
		break;
	case MTD_ROM:
		type = "rom";
		break;
	case MTD_NORFLASH:
		type = "nor";
		break;
	case MTD_NANDFLASH:
		type = "nand";
		break;
	case MTD_DATAFLASH:
		type = "dataflash";
		break;
	case MTD_UBIVOLUME:
		type = "ubi";
		break;
	default:
		type = "unknown";
	}

	return snprintf(buf, PAGE_SIZE, "%s\n", type);
}
169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211
static DEVICE_ATTR(type, S_IRUGO, mtd_type_show, NULL);

static ssize_t mtd_flags_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_to_mtd(dev);

	return snprintf(buf, PAGE_SIZE, "0x%lx\n", (unsigned long)mtd->flags);

}
static DEVICE_ATTR(flags, S_IRUGO, mtd_flags_show, NULL);

static ssize_t mtd_size_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_to_mtd(dev);

	return snprintf(buf, PAGE_SIZE, "%llu\n",
		(unsigned long long)mtd->size);

}
static DEVICE_ATTR(size, S_IRUGO, mtd_size_show, NULL);

static ssize_t mtd_erasesize_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_to_mtd(dev);

	return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->erasesize);

}
static DEVICE_ATTR(erasesize, S_IRUGO, mtd_erasesize_show, NULL);

static ssize_t mtd_writesize_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_to_mtd(dev);

	return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->writesize);

}
static DEVICE_ATTR(writesize, S_IRUGO, mtd_writesize_show, NULL);

212 213 214 215 216 217 218 219 220 221 222
static ssize_t mtd_subpagesize_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_to_mtd(dev);
	unsigned int subpagesize = mtd->writesize >> mtd->subpage_sft;

	return snprintf(buf, PAGE_SIZE, "%u\n", subpagesize);

}
static DEVICE_ATTR(subpagesize, S_IRUGO, mtd_subpagesize_show, NULL);

223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252
static ssize_t mtd_oobsize_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_to_mtd(dev);

	return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->oobsize);

}
static DEVICE_ATTR(oobsize, S_IRUGO, mtd_oobsize_show, NULL);

static ssize_t mtd_numeraseregions_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_to_mtd(dev);

	return snprintf(buf, PAGE_SIZE, "%u\n", mtd->numeraseregions);

}
static DEVICE_ATTR(numeraseregions, S_IRUGO, mtd_numeraseregions_show,
	NULL);

static ssize_t mtd_name_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct mtd_info *mtd = dev_to_mtd(dev);

	return snprintf(buf, PAGE_SIZE, "%s\n", mtd->name);

}
static DEVICE_ATTR(name, S_IRUGO, mtd_name_show, NULL);
David Brownell's avatar
David Brownell committed
253 254

static struct attribute *mtd_attrs[] = {
255 256 257 258 259
	&dev_attr_type.attr,
	&dev_attr_flags.attr,
	&dev_attr_size.attr,
	&dev_attr_erasesize.attr,
	&dev_attr_writesize.attr,
260
	&dev_attr_subpagesize.attr,
261 262 263
	&dev_attr_oobsize.attr,
	&dev_attr_numeraseregions.attr,
	&dev_attr_name.attr,
David Brownell's avatar
David Brownell committed
264 265 266
	NULL,
};

267
static struct attribute_group mtd_group = {
David Brownell's avatar
David Brownell committed
268 269 270
	.attrs		= mtd_attrs,
};

271
static const struct attribute_group *mtd_groups[] = {
David Brownell's avatar
David Brownell committed
272 273 274 275 276 277 278 279 280 281
	&mtd_group,
	NULL,
};

static struct device_type mtd_devtype = {
	.name		= "mtd",
	.groups		= mtd_groups,
	.release	= mtd_release,
};

Linus Torvalds's avatar
Linus Torvalds committed
282 283 284 285 286 287 288
/**
 *	add_mtd_device - register an MTD device
 *	@mtd: pointer to new MTD device info structure
 *
 *	Add a device to the list of MTD devices present in the system, and
 *	notify each currently active MTD 'user' of its arrival. Returns
 *	zero on success or 1 on failure, which currently will only happen
289
 *	if there is insufficient memory or a sysfs error.
Linus Torvalds's avatar
Linus Torvalds committed
290 291 292 293
 */

int add_mtd_device(struct mtd_info *mtd)
{
294 295
	struct mtd_notifier *not;
	int i, error;
Linus Torvalds's avatar
Linus Torvalds committed
296

297 298 299 300 301 302 303 304 305 306 307 308 309 310
	if (!mtd->backing_dev_info) {
		switch (mtd->type) {
		case MTD_RAM:
			mtd->backing_dev_info = &mtd_bdi_rw_mappable;
			break;
		case MTD_ROM:
			mtd->backing_dev_info = &mtd_bdi_ro_mappable;
			break;
		default:
			mtd->backing_dev_info = &mtd_bdi_unmappable;
			break;
		}
	}

311
	BUG_ON(mtd->writesize == 0);
Ingo Molnar's avatar
Ingo Molnar committed
312
	mutex_lock(&mtd_table_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
313

314 315 316 317 318
	do {
		if (!idr_pre_get(&mtd_idr, GFP_KERNEL))
			goto fail_locked;
		error = idr_get_new(&mtd_idr, mtd, &i);
	} while (error == -EAGAIN);
319

320 321
	if (error)
		goto fail_locked;
David Brownell's avatar
David Brownell committed
322

323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376
	mtd->index = i;
	mtd->usecount = 0;

	if (is_power_of_2(mtd->erasesize))
		mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
	else
		mtd->erasesize_shift = 0;

	if (is_power_of_2(mtd->writesize))
		mtd->writesize_shift = ffs(mtd->writesize) - 1;
	else
		mtd->writesize_shift = 0;

	mtd->erasesize_mask = (1 << mtd->erasesize_shift) - 1;
	mtd->writesize_mask = (1 << mtd->writesize_shift) - 1;

	/* Some chips always power up locked. Unlock them now */
	if ((mtd->flags & MTD_WRITEABLE)
	    && (mtd->flags & MTD_POWERUP_LOCK) && mtd->unlock) {
		if (mtd->unlock(mtd, 0, mtd->size))
			printk(KERN_WARNING
			       "%s: unlock failed, writes may not work\n",
			       mtd->name);
	}

	/* Caller should have set dev.parent to match the
	 * physical device.
	 */
	mtd->dev.type = &mtd_devtype;
	mtd->dev.class = &mtd_class;
	mtd->dev.devt = MTD_DEVT(i);
	dev_set_name(&mtd->dev, "mtd%d", i);
	dev_set_drvdata(&mtd->dev, mtd);
	if (device_register(&mtd->dev) != 0)
		goto fail_added;

	if (MTD_DEVT(i))
		device_create(&mtd_class, mtd->dev.parent,
			      MTD_DEVT(i) + 1,
			      NULL, "mtd%dro", i);

	DEBUG(0, "mtd: Giving out device %d to %s\n", i, mtd->name);
	/* No need to get a refcount on the module containing
	   the notifier, since we hold the mtd_table_mutex */
	list_for_each_entry(not, &mtd_notifiers, list)
		not->add(mtd);

	mutex_unlock(&mtd_table_mutex);
	/* We _know_ we aren't being removed, because
	   our caller is still holding us here. So none
	   of this try_ nonsense, and no bitching about it
	   either. :) */
	__module_get(THIS_MODULE);
	return 0;
377

378 379 380
fail_added:
	idr_remove(&mtd_idr, i);
fail_locked:
Ingo Molnar's avatar
Ingo Molnar committed
381
	mutex_unlock(&mtd_table_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397
	return 1;
}

/**
 *	del_mtd_device - unregister an MTD device
 *	@mtd: pointer to MTD device info structure
 *
 *	Remove a device from the list of MTD devices present in the system,
 *	and notify each currently active MTD 'user' of its departure.
 *	Returns zero on success or 1 on failure, which currently will happen
 *	if the requested device does not appear to be present in the list.
 */

int del_mtd_device (struct mtd_info *mtd)
{
	int ret;
398
	struct mtd_notifier *not;
399

Ingo Molnar's avatar
Ingo Molnar committed
400
	mutex_lock(&mtd_table_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
401

402
	if (idr_find(&mtd_idr, mtd->index) != mtd) {
Linus Torvalds's avatar
Linus Torvalds committed
403
		ret = -ENODEV;
404 405 406 407 408 409 410 411 412
		goto out_error;
	}

	/* No need to get a refcount on the module containing
		the notifier, since we hold the mtd_table_mutex */
	list_for_each_entry(not, &mtd_notifiers, list)
		not->remove(mtd);

	if (mtd->usecount) {
413
		printk(KERN_NOTICE "Removing MTD device #%d (%s) with use count %d\n",
Linus Torvalds's avatar
Linus Torvalds committed
414 415 416
		       mtd->index, mtd->name, mtd->usecount);
		ret = -EBUSY;
	} else {
417 418
		device_unregister(&mtd->dev);

419
		idr_remove(&mtd_idr, mtd->index);
Linus Torvalds's avatar
Linus Torvalds committed
420 421 422 423 424

		module_put(THIS_MODULE);
		ret = 0;
	}

425
out_error:
Ingo Molnar's avatar
Ingo Molnar committed
426
	mutex_unlock(&mtd_table_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
427 428 429 430 431 432 433 434 435 436 437 438 439 440
	return ret;
}

/**
 *	register_mtd_user - register a 'user' of MTD devices.
 *	@new: pointer to notifier info structure
 *
 *	Registers a pair of callbacks function to be called upon addition
 *	or removal of MTD devices. Causes the 'add' callback to be immediately
 *	invoked for each MTD device currently present in the system.
 */

void register_mtd_user (struct mtd_notifier *new)
{
441
	struct mtd_info *mtd;
Linus Torvalds's avatar
Linus Torvalds committed
442

Ingo Molnar's avatar
Ingo Molnar committed
443
	mutex_lock(&mtd_table_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
444 445 446 447

	list_add(&new->list, &mtd_notifiers);

 	__module_get(THIS_MODULE);
448

449 450
	mtd_for_each_device(mtd)
		new->add(mtd);
Linus Torvalds's avatar
Linus Torvalds committed
451

Ingo Molnar's avatar
Ingo Molnar committed
452
	mutex_unlock(&mtd_table_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
453 454 455
}

/**
456 457
 *	unregister_mtd_user - unregister a 'user' of MTD devices.
 *	@old: pointer to notifier info structure
Linus Torvalds's avatar
Linus Torvalds committed
458 459 460 461 462 463 464 465 466
 *
 *	Removes a callback function pair from the list of 'users' to be
 *	notified upon addition or removal of MTD devices. Causes the
 *	'remove' callback to be immediately invoked for each MTD device
 *	currently present in the system.
 */

int unregister_mtd_user (struct mtd_notifier *old)
{
467
	struct mtd_info *mtd;
Linus Torvalds's avatar
Linus Torvalds committed
468

Ingo Molnar's avatar
Ingo Molnar committed
469
	mutex_lock(&mtd_table_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
470 471 472

	module_put(THIS_MODULE);

473 474
	mtd_for_each_device(mtd)
		old->remove(mtd);
475

Linus Torvalds's avatar
Linus Torvalds committed
476
	list_del(&old->list);
Ingo Molnar's avatar
Ingo Molnar committed
477
	mutex_unlock(&mtd_table_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
478 479 480 481 482 483 484 485 486 487 488 489
	return 0;
}


/**
 *	get_mtd_device - obtain a validated handle for an MTD device
 *	@mtd: last known address of the required MTD device
 *	@num: internal device number of the required MTD device
 *
 *	Given a number and NULL address, return the num'th entry in the device
 *	table, if any.	Given an address and num == -1, search the device table
 *	for a device with that address and return if it's still present. Given
490 491
 *	both, return the num'th driver only if its address matches. Return
 *	error code if not.
Linus Torvalds's avatar
Linus Torvalds committed
492
 */
493

Linus Torvalds's avatar
Linus Torvalds committed
494 495
struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
{
496 497
	struct mtd_info *ret = NULL, *other;
	int err = -ENODEV;
Linus Torvalds's avatar
Linus Torvalds committed
498

Ingo Molnar's avatar
Ingo Molnar committed
499
	mutex_lock(&mtd_table_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
500 501

	if (num == -1) {
502 503 504 505 506 507
		mtd_for_each_device(other) {
			if (other == mtd) {
				ret = mtd;
				break;
			}
		}
508 509
	} else if (num >= 0) {
		ret = idr_find(&mtd_idr, num);
Linus Torvalds's avatar
Linus Torvalds committed
510 511 512 513
		if (mtd && mtd != ret)
			ret = NULL;
	}

514 515 516
	if (!ret) {
		ret = ERR_PTR(err);
		goto out;
517
	}
Linus Torvalds's avatar
Linus Torvalds committed
518

519 520 521 522
	err = __get_mtd_device(ret);
	if (err)
		ret = ERR_PTR(err);
out:
523 524
	mutex_unlock(&mtd_table_mutex);
	return ret;
525
}
Linus Torvalds's avatar
Linus Torvalds committed
526

527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545

int __get_mtd_device(struct mtd_info *mtd)
{
	int err;

	if (!try_module_get(mtd->owner))
		return -ENODEV;

	if (mtd->get_device) {

		err = mtd->get_device(mtd);

		if (err) {
			module_put(mtd->owner);
			return err;
		}
	}
	mtd->usecount++;
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
546 547
}

548 549 550 551 552 553 554 555 556 557 558
/**
 *	get_mtd_device_nm - obtain a validated handle for an MTD device by
 *	device name
 *	@name: MTD device name to open
 *
 * 	This function returns MTD device description structure in case of
 * 	success and an error code in case of failure.
 */

struct mtd_info *get_mtd_device_nm(const char *name)
{
559 560
	int err = -ENODEV;
	struct mtd_info *mtd = NULL, *other;
561 562 563

	mutex_lock(&mtd_table_mutex);

564 565 566
	mtd_for_each_device(other) {
		if (!strcmp(name, other->name)) {
			mtd = other;
567 568 569 570
			break;
		}
	}

571
	if (!mtd)
572 573 574 575 576
		goto out_unlock;

	if (!try_module_get(mtd->owner))
		goto out_unlock;

577 578 579 580 581 582
	if (mtd->get_device) {
		err = mtd->get_device(mtd);
		if (err)
			goto out_put;
	}

583
	mtd->usecount++;
584 585
	mutex_unlock(&mtd_table_mutex);
	return mtd;
586

587 588
out_put:
	module_put(mtd->owner);
589 590
out_unlock:
	mutex_unlock(&mtd_table_mutex);
591
	return ERR_PTR(err);
592 593
}

Linus Torvalds's avatar
Linus Torvalds committed
594 595
void put_mtd_device(struct mtd_info *mtd)
{
Ingo Molnar's avatar
Ingo Molnar committed
596
	mutex_lock(&mtd_table_mutex);
597 598 599 600 601 602 603 604 605 606
	__put_mtd_device(mtd);
	mutex_unlock(&mtd_table_mutex);

}

void __put_mtd_device(struct mtd_info *mtd)
{
	--mtd->usecount;
	BUG_ON(mtd->usecount < 0);

607 608
	if (mtd->put_device)
		mtd->put_device(mtd);
Linus Torvalds's avatar
Linus Torvalds committed
609 610 611 612 613

	module_put(mtd->owner);
}

/* default_mtd_writev - default mtd writev method for MTD devices that
614
 *			don't implement their own
Linus Torvalds's avatar
Linus Torvalds committed
615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641
 */

int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
		       unsigned long count, loff_t to, size_t *retlen)
{
	unsigned long i;
	size_t totlen = 0, thislen;
	int ret = 0;

	if(!mtd->write) {
		ret = -EROFS;
	} else {
		for (i=0; i<count; i++) {
			if (!vecs[i].iov_len)
				continue;
			ret = mtd->write(mtd, to, vecs[i].iov_len, &thislen, vecs[i].iov_base);
			totlen += thislen;
			if (ret || thislen != vecs[i].iov_len)
				break;
			to += vecs[i].iov_len;
		}
	}
	if (retlen)
		*retlen = totlen;
	return ret;
}

642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689
/**
 * mtd_kmalloc_up_to - allocate a contiguous buffer up to the specified size
 * @size: A pointer to the ideal or maximum size of the allocation. Points
 *        to the actual allocation size on success.
 *
 * This routine attempts to allocate a contiguous kernel buffer up to
 * the specified size, backing off the size of the request exponentially
 * until the request succeeds or until the allocation size falls below
 * the system page size. This attempts to make sure it does not adversely
 * impact system performance, so when allocating more than one page, we
 * ask the memory allocator to avoid re-trying, swapping, writing back
 * or performing I/O.
 *
 * Note, this function also makes sure that the allocated buffer is aligned to
 * the MTD device's min. I/O unit, i.e. the "mtd->writesize" value.
 *
 * This is called, for example by mtd_{read,write} and jffs2_scan_medium,
 * to handle smaller (i.e. degraded) buffer allocations under low- or
 * fragmented-memory situations where such reduced allocations, from a
 * requested ideal, are allowed.
 *
 * Returns a pointer to the allocated buffer on success; otherwise, NULL.
 */
void *mtd_kmalloc_up_to(const struct mtd_info *mtd, size_t *size)
{
	gfp_t flags = __GFP_NOWARN | __GFP_WAIT |
		       __GFP_NORETRY | __GFP_NO_KSWAPD;
	size_t min_alloc = max_t(size_t, mtd->writesize, PAGE_SIZE);
	void *kbuf;

	*size = min_t(size_t, *size, KMALLOC_MAX_SIZE);

	while (*size > min_alloc) {
		kbuf = kmalloc(*size, flags);
		if (kbuf)
			return kbuf;

		*size >>= 1;
		*size = ALIGN(*size, mtd->writesize);
	}

	/*
	 * For the last resort allocation allow 'kmalloc()' to do all sorts of
	 * things (write-back, dropping caches, etc) by using GFP_KERNEL.
	 */
	return kmalloc(*size, GFP_KERNEL);
}

690 691 692 693
EXPORT_SYMBOL_GPL(add_mtd_device);
EXPORT_SYMBOL_GPL(del_mtd_device);
EXPORT_SYMBOL_GPL(get_mtd_device);
EXPORT_SYMBOL_GPL(get_mtd_device_nm);
694
EXPORT_SYMBOL_GPL(__get_mtd_device);
695
EXPORT_SYMBOL_GPL(put_mtd_device);
696
EXPORT_SYMBOL_GPL(__put_mtd_device);
697 698 699
EXPORT_SYMBOL_GPL(register_mtd_user);
EXPORT_SYMBOL_GPL(unregister_mtd_user);
EXPORT_SYMBOL_GPL(default_mtd_writev);
700
EXPORT_SYMBOL_GPL(mtd_kmalloc_up_to);
Linus Torvalds's avatar
Linus Torvalds committed
701

702 703
#ifdef CONFIG_PROC_FS

Linus Torvalds's avatar
Linus Torvalds committed
704 705 706 707 708
/*====================================================================*/
/* Support for /proc/mtd */

static struct proc_dir_entry *proc_mtd;

709
static int mtd_proc_show(struct seq_file *m, void *v)
Linus Torvalds's avatar
Linus Torvalds committed
710
{
711
	struct mtd_info *mtd;
Linus Torvalds's avatar
Linus Torvalds committed
712

713
	seq_puts(m, "dev:    size   erasesize  name\n");
Ingo Molnar's avatar
Ingo Molnar committed
714
	mutex_lock(&mtd_table_mutex);
715
	mtd_for_each_device(mtd) {
716 717 718
		seq_printf(m, "mtd%d: %8.8llx %8.8x \"%s\"\n",
			   mtd->index, (unsigned long long)mtd->size,
			   mtd->erasesize, mtd->name);
Linus Torvalds's avatar
Linus Torvalds committed
719
        }
Ingo Molnar's avatar
Ingo Molnar committed
720
	mutex_unlock(&mtd_table_mutex);
721
        return 0;
Linus Torvalds's avatar
Linus Torvalds committed
722 723
}

724 725 726 727 728 729 730 731 732 733 734
static int mtd_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, mtd_proc_show, NULL);
}

static const struct file_operations mtd_proc_ops = {
	.open		= mtd_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};
735 736
#endif /* CONFIG_PROC_FS */

Linus Torvalds's avatar
Linus Torvalds committed
737 738 739
/*====================================================================*/
/* Init code */

740 741 742 743 744 745 746 747 748 749 750 751 752 753
static int __init mtd_bdi_init(struct backing_dev_info *bdi, const char *name)
{
	int ret;

	ret = bdi_init(bdi);
	if (!ret)
		ret = bdi_register(bdi, NULL, name);

	if (ret)
		bdi_destroy(bdi);

	return ret;
}

Linus Torvalds's avatar
Linus Torvalds committed
754 755
static int __init init_mtd(void)
{
756
	int ret;
757

758
	ret = class_register(&mtd_class);
759 760 761 762 763 764 765 766 767 768 769 770 771 772
	if (ret)
		goto err_reg;

	ret = mtd_bdi_init(&mtd_bdi_unmappable, "mtd-unmap");
	if (ret)
		goto err_bdi1;

	ret = mtd_bdi_init(&mtd_bdi_ro_mappable, "mtd-romap");
	if (ret)
		goto err_bdi2;

	ret = mtd_bdi_init(&mtd_bdi_rw_mappable, "mtd-rwmap");
	if (ret)
		goto err_bdi3;
773

774
#ifdef CONFIG_PROC_FS
775
	proc_mtd = proc_create("mtd", 0, NULL, &mtd_proc_ops);
776
#endif /* CONFIG_PROC_FS */
Linus Torvalds's avatar
Linus Torvalds committed
777
	return 0;
778 779 780 781 782 783 784 785 786 787

err_bdi3:
	bdi_destroy(&mtd_bdi_ro_mappable);
err_bdi2:
	bdi_destroy(&mtd_bdi_unmappable);
err_bdi1:
	class_unregister(&mtd_class);
err_reg:
	pr_err("Error registering mtd class or bdi: %d\n", ret);
	return ret;
Linus Torvalds's avatar
Linus Torvalds committed
788 789 790 791
}

static void __exit cleanup_mtd(void)
{
792
#ifdef CONFIG_PROC_FS
Linus Torvalds's avatar
Linus Torvalds committed
793 794
        if (proc_mtd)
		remove_proc_entry( "mtd", NULL);
795
#endif /* CONFIG_PROC_FS */
796
	class_unregister(&mtd_class);
797 798 799
	bdi_destroy(&mtd_bdi_unmappable);
	bdi_destroy(&mtd_bdi_ro_mappable);
	bdi_destroy(&mtd_bdi_rw_mappable);
Linus Torvalds's avatar
Linus Torvalds committed
800 801 802 803 804 805 806 807
}

module_init(init_mtd);
module_exit(cleanup_mtd);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
MODULE_DESCRIPTION("Core MTD registration and access routines");