1/*
   2 * Copyright © 2009 - Maxim Levitsky
   3 * SmartMedia/xD translation layer
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License version 2 as
   7 * published by the Free Software Foundation.
   8 */
   9
  10#include <linux/kernel.h>
  11#include <linux/module.h>
  12#include <linux/random.h>
  13#include <linux/hdreg.h>
  14#include <linux/kthread.h>
  15#include <linux/freezer.h>
  16#include <linux/sysfs.h>
  17#include <linux/bitops.h>
  18#include <linux/slab.h>
  19#include <linux/mtd/nand_ecc.h>
  20#include "nand/sm_common.h"
  21#include "sm_ftl.h"
  22
  23
  24
  25struct workqueue_struct *cache_flush_workqueue;
  26
  27static int cache_timeout = 1000;
  28module_param(cache_timeout, bool, S_IRUGO);
  29MODULE_PARM_DESC(cache_timeout,
  30	"Timeout (in ms) for cache flush (1000 ms default");
  31
  32static int debug;
  33module_param(debug, int, S_IRUGO | S_IWUSR);
  34MODULE_PARM_DESC(debug, "Debug level (0-2)");
  35
  36
  37/* ------------------- sysfs attributtes ---------------------------------- */
  38struct sm_sysfs_attribute {
  39	struct device_attribute dev_attr;
  40	char *data;
  41	int len;
  42};
  43
  44ssize_t sm_attr_show(struct device *dev, struct device_attribute *attr,
  45		     char *buf)
  46{
  47	struct sm_sysfs_attribute *sm_attr =
  48		container_of(attr, struct sm_sysfs_attribute, dev_attr);
  49
  50	strncpy(buf, sm_attr->data, sm_attr->len);
  51	return sm_attr->len;
  52}
  53
  54
  55#define NUM_ATTRIBUTES 1
  56#define SM_CIS_VENDOR_OFFSET 0x59
  57struct attribute_group *sm_create_sysfs_attributes(struct sm_ftl *ftl)
  58{
  59	struct attribute_group *attr_group;
  60	struct attribute **attributes;
  61	struct sm_sysfs_attribute *vendor_attribute;
  62
  63	int vendor_len = strnlen(ftl->cis_buffer + SM_CIS_VENDOR_OFFSET,
  64					SM_SMALL_PAGE - SM_CIS_VENDOR_OFFSET);
  65
  66	char *vendor = kmalloc(vendor_len, GFP_KERNEL);
  67	if (!vendor)
  68		goto error1;
  69	memcpy(vendor, ftl->cis_buffer + SM_CIS_VENDOR_OFFSET, vendor_len);
  70	vendor[vendor_len] = 0;
  71
  72	/* Initialize sysfs attributes */
  73	vendor_attribute =
  74		kzalloc(sizeof(struct sm_sysfs_attribute), GFP_KERNEL);
  75	if (!vendor_attribute)
  76		goto error2;
  77
  78	sysfs_attr_init(&vendor_attribute->dev_attr.attr);
  79
  80	vendor_attribute->data = vendor;
  81	vendor_attribute->len = vendor_len;
  82	vendor_attribute->dev_attr.attr.name = "vendor";
  83	vendor_attribute->dev_attr.attr.mode = S_IRUGO;
  84	vendor_attribute->dev_attr.show = sm_attr_show;
  85
  86
  87	/* Create array of pointers to the attributes */
  88	attributes = kzalloc(sizeof(struct attribute *) * (NUM_ATTRIBUTES + 1),
  89								GFP_KERNEL);
  90	if (!attributes)
  91		goto error3;
  92	attributes[0] = &vendor_attribute->dev_attr.attr;
  93
  94	/* Finally create the attribute group */
  95	attr_group = kzalloc(sizeof(struct attribute_group), GFP_KERNEL);
  96	if (!attr_group)
  97		goto error4;
  98	attr_group->attrs = attributes;
  99	return attr_group;
 100error4:
 101	kfree(attributes);
 102error3:
 103	kfree(vendor_attribute);
 104error2:
 105	kfree(vendor);
 106error1:
 107	return NULL;
 108}
 109
 110void sm_delete_sysfs_attributes(struct sm_ftl *ftl)
 111{
 112	struct attribute **attributes = ftl->disk_attributes->attrs;
 113	int i;
 114
 115	for (i = 0; attributes[i] ; i++) {
 116
 117		struct device_attribute *dev_attr = container_of(attributes[i],
 118			struct device_attribute, attr);
 119
 120		struct sm_sysfs_attribute *sm_attr =
 121			container_of(dev_attr,
 122				struct sm_sysfs_attribute, dev_attr);
 123
 124		kfree(sm_attr->data);
 125		kfree(sm_attr);
 126	}
 127
 128	kfree(ftl->disk_attributes->attrs);
 129	kfree(ftl->disk_attributes);
 130}
 131
 132
 133/* ----------------------- oob helpers -------------------------------------- */
 134
 135static int sm_get_lba(uint8_t *lba)
 136{
 137	/* check fixed bits */
 138	if ((lba[0] & 0xF8) != 0x10)
 139		return -2;
 140
 141	/* check parity - endianess doesn't matter */
 142	if (hweight16(*(uint16_t *)lba) & 1)
 143		return -2;
 144
 145	return (lba[1] >> 1) | ((lba[0] & 0x07) << 7);
 146}
 147
 148
 149/*
 150 * Read LBA asscociated with block
 151 * returns -1, if block is erased
 152 * returns -2 if error happens
 153 */
 154static int sm_read_lba(struct sm_oob *oob)
 155{
 156	static const uint32_t erased_pattern[4] = {
 157		0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
 158
 159	uint16_t lba_test;
 160	int lba;
 161
 162	/* First test for erased block */
 163	if (!memcmp(oob, erased_pattern, SM_OOB_SIZE))
 164		return -1;
 165
 166	/* Now check is both copies of the LBA differ too much */
 167	lba_test = *(uint16_t *)oob->lba_copy1 ^ *(uint16_t*)oob->lba_copy2;
 168	if (lba_test && !is_power_of_2(lba_test))
 169		return -2;
 170
 171	/* And read it */
 172	lba = sm_get_lba(oob->lba_copy1);
 173
 174	if (lba == -2)
 175		lba = sm_get_lba(oob->lba_copy2);
 176
 177	return lba;
 178}
 179
 180static void sm_write_lba(struct sm_oob *oob, uint16_t lba)
 181{
 182	uint8_t tmp[2];
 183
 184	WARN_ON(lba >= 1000);
 185
 186	tmp[0] = 0x10 | ((lba >> 7) & 0x07);
 187	tmp[1] = (lba << 1) & 0xFF;
 188
 189	if (hweight16(*(uint16_t *)tmp) & 0x01)
 190		tmp[1] |= 1;
 191
 192	oob->lba_copy1[0] = oob->lba_copy2[0] = tmp[0];
 193	oob->lba_copy1[1] = oob->lba_copy2[1] = tmp[1];
 194}
 195
 196
 197/* Make offset from parts */
 198static loff_t sm_mkoffset(struct sm_ftl *ftl, int zone, int block, int boffset)
 199{
 200	WARN_ON(boffset & (SM_SECTOR_SIZE - 1));
 201	WARN_ON(zone < 0 || zone >= ftl->zone_count);
 202	WARN_ON(block >= ftl->zone_size);
 203	WARN_ON(boffset >= ftl->block_size);
 204
 205	if (block == -1)
 206		return -1;
 207
 208	return (zone * SM_MAX_ZONE_SIZE + block) * ftl->block_size + boffset;
 209}
 210
 211/* Breaks offset into parts */
 212static void sm_break_offset(struct sm_ftl *ftl, loff_t offset,
 213			    int *zone, int *block, int *boffset)
 214{
 215	*boffset = do_div(offset, ftl->block_size);
 216	*block = do_div(offset, ftl->max_lba);
 217	*zone = offset >= ftl->zone_count ? -1 : offset;
 218}
 219
 220/* ---------------------- low level IO ------------------------------------- */
 221
 222static int sm_correct_sector(uint8_t *buffer, struct sm_oob *oob)
 223{
 224	uint8_t ecc[3];
 225
 226	__nand_calculate_ecc(buffer, SM_SMALL_PAGE, ecc);
 227	if (__nand_correct_data(buffer, ecc, oob->ecc1, SM_SMALL_PAGE) < 0)
 228		return -EIO;
 229
 230	buffer += SM_SMALL_PAGE;
 231
 232	__nand_calculate_ecc(buffer, SM_SMALL_PAGE, ecc);
 233	if (__nand_correct_data(buffer, ecc, oob->ecc2, SM_SMALL_PAGE) < 0)
 234		return -EIO;
 235	return 0;
 236}
 237
 238/* Reads a sector + oob*/
 239static int sm_read_sector(struct sm_ftl *ftl,
 240			  int zone, int block, int boffset,
 241			  uint8_t *buffer, struct sm_oob *oob)
 242{
 243	struct mtd_info *mtd = ftl->trans->mtd;
 244	struct mtd_oob_ops ops;
 245	struct sm_oob tmp_oob;
 246	int ret = -EIO;
 247	int try = 0;
 248
 249	/* FTL can contain -1 entries that are by default filled with bits */
 250	if (block == -1) {
 251		memset(buffer, 0xFF, SM_SECTOR_SIZE);
 252		return 0;
 253	}
 254
 255	/* User might not need the oob, but we do for data vertification */
 256	if (!oob)
 257		oob = &tmp_oob;
 258
 259	ops.mode = ftl->smallpagenand ? MTD_OOB_RAW : MTD_OOB_PLACE;
 260	ops.ooboffs = 0;
 261	ops.ooblen = SM_OOB_SIZE;
 262	ops.oobbuf = (void *)oob;
 263	ops.len = SM_SECTOR_SIZE;
 264	ops.datbuf = buffer;
 265
 266again:
 267	if (try++) {
 268		/* Avoid infinite recursion on CIS reads, sm_recheck_media
 269			won't help anyway */
 270		if (zone == 0 && block == ftl->cis_block && boffset ==
 271			ftl->cis_boffset)
 272			return ret;
 273
 274		/* Test if media is stable */
 275		if (try == 3 || sm_recheck_media(ftl))
 276			return ret;
 277	}
 278
 279	/* Unfortunelly, oob read will _always_ succeed,
 280		despite card removal..... */
 281	ret = mtd->read_oob(mtd, sm_mkoffset(ftl, zone, block, boffset), &ops);
 282
 283	/* Test for unknown errors */
 284	if (ret != 0 && ret != -EUCLEAN && ret != -EBADMSG) {
 285		dbg("read of block %d at zone %d, failed due to error (%d)",
 286			block, zone, ret);
 287		goto again;
 288	}
 289
 290	/* Do a basic test on the oob, to guard against returned garbage */
 291	if (oob->reserved != 0xFFFFFFFF && !is_power_of_2(~oob->reserved))
 292		goto again;
 293
 294	/* This should never happen, unless there is a bug in the mtd driver */
 295	WARN_ON(ops.oobretlen != SM_OOB_SIZE);
 296	WARN_ON(buffer && ops.retlen != SM_SECTOR_SIZE);
 297
 298	if (!buffer)
 299		return 0;
 300
 301	/* Test if sector marked as bad */
 302	if (!sm_sector_valid(oob)) {
 303		dbg("read of block %d at zone %d, failed because it is marked"
 304			" as bad" , block, zone);
 305		goto again;
 306	}
 307
 308	/* Test ECC*/
 309	if (ret == -EBADMSG ||
 310		(ftl->smallpagenand && sm_correct_sector(buffer, oob))) {
 311
 312		dbg("read of block %d at zone %d, failed due to ECC error",
 313			block, zone);
 314		goto again;
 315	}
 316
 317	return 0;
 318}
 319
 320/* Writes a sector to media */
 321static int sm_write_sector(struct sm_ftl *ftl,
 322			   int zone, int block, int boffset,
 323			   uint8_t *buffer, struct sm_oob *oob)
 324{
 325	struct mtd_oob_ops ops;
 326	struct mtd_info *mtd = ftl->trans->mtd;
 327	int ret;
 328
 329	BUG_ON(ftl->readonly);
 330
 331	if (zone == 0 && (block == ftl->cis_block || block == 0)) {
 332		dbg("attempted to write the CIS!");
 333		return -EIO;
 334	}
 335
 336	if (ftl->unstable)
 337		return -EIO;
 338
 339	ops.mode = ftl->smallpagenand ? MTD_OOB_RAW : MTD_OOB_PLACE;
 340	ops.len = SM_SECTOR_SIZE;
 341	ops.datbuf = buffer;
 342	ops.ooboffs = 0;
 343	ops.ooblen = SM_OOB_SIZE;
 344	ops.oobbuf = (void *)oob;
 345
 346	ret = mtd->write_oob(mtd, sm_mkoffset(ftl, zone, block, boffset), &ops);
 347
 348	/* Now we assume that hardware will catch write bitflip errors */
 349	/* If you are paranoid, use CONFIG_MTD_NAND_VERIFY_WRITE */
 350
 351	if (ret) {
 352		dbg("write to block %d at zone %d, failed with error %d",
 353			block, zone, ret);
 354
 355		sm_recheck_media(ftl);
 356		return ret;
 357	}
 358
 359	/* This should never happen, unless there is a bug in the driver */
 360	WARN_ON(ops.oobretlen != SM_OOB_SIZE);
 361	WARN_ON(buffer && ops.retlen != SM_SECTOR_SIZE);
 362
 363	return 0;
 364}
 365
 366/* ------------------------ block IO ------------------------------------- */
 367
 368/* Write a block using data and lba, and invalid sector bitmap */
 369static int sm_write_block(struct sm_ftl *ftl, uint8_t *buf,
 370			  int zone, int block, int lba,
 371			  unsigned long invalid_bitmap)
 372{
 373	struct sm_oob oob;
 374	int boffset;
 375	int retry = 0;
 376
 377	/* Initialize the oob with requested values */
 378	memset(&oob, 0xFF, SM_OOB_SIZE);
 379	sm_write_lba(&oob, lba);
 380restart:
 381	if (ftl->unstable)
 382		return -EIO;
 383
 384	for (boffset = 0; boffset < ftl->block_size;
 385				boffset += SM_SECTOR_SIZE) {
 386
 387		oob.data_status = 0xFF;
 388
 389		if (test_bit(boffset / SM_SECTOR_SIZE, &invalid_bitmap)) {
 390
 391			sm_printk("sector %d of block at LBA %d of zone %d"
 392				" coudn't be read, marking it as invalid",
 393				boffset / SM_SECTOR_SIZE, lba, zone);
 394
 395			oob.data_status = 0;
 396		}
 397
 398		if (ftl->smallpagenand) {
 399			__nand_calculate_ecc(buf + boffset,
 400						SM_SMALL_PAGE, oob.ecc1);
 401
 402			__nand_calculate_ecc(buf + boffset + SM_SMALL_PAGE,
 403						SM_SMALL_PAGE, oob.ecc2);
 404		}
 405		if (!sm_write_sector(ftl, zone, block, boffset,
 406							buf + boffset, &oob))
 407			continue;
 408
 409		if (!retry) {
 410
 411			/* If write fails. try to erase the block */
 412			/* This is safe, because we never write in blocks
 413				that contain valuable data.
 414			This is intended to repair block that are marked
 415			as erased, but that isn't fully erased*/
 416
 417			if (sm_erase_block(ftl, zone, block, 0))
 418				return -EIO;
 419
 420			retry = 1;
 421			goto restart;
 422		} else {
 423			sm_mark_block_bad(ftl, zone, block);
 424			return -EIO;
 425		}
 426	}
 427	return 0;
 428}
 429
 430
 431/* Mark whole block at offset 'offs' as bad. */
 432static void sm_mark_block_bad(struct sm_ftl *ftl, int zone, int block)
 433{
 434	struct sm_oob oob;
 435	int boffset;
 436
 437	memset(&oob, 0xFF, SM_OOB_SIZE);
 438	oob.block_status = 0xF0;
 439
 440	if (ftl->unstable)
 441		return;
 442
 443	if (sm_recheck_media(ftl))
 444		return;
 445
 446	sm_printk("marking block %d of zone %d as bad", block, zone);
 447
 448	/* We aren't checking the return value, because we don't care */
 449	/* This also fails on fake xD cards, but I guess these won't expose
 450		any bad blocks till fail completly */
 451	for (boffset = 0; boffset < ftl->block_size; boffset += SM_SECTOR_SIZE)
 452		sm_write_sector(ftl, zone, block, boffset, NULL, &oob);
 453}
 454
 455/*
 456 * Erase a block within a zone
 457 * If erase succedes, it updates free block fifo, otherwise marks block as bad
 458 */
 459static int sm_erase_block(struct sm_ftl *ftl, int zone_num, uint16_t block,
 460			  int put_free)
 461{
 462	struct ftl_zone *zone = &ftl->zones[zone_num];
 463	struct mtd_info *mtd = ftl->trans->mtd;
 464	struct erase_info erase;
 465
 466	erase.mtd = mtd;
 467	erase.callback = sm_erase_callback;
 468	erase.addr = sm_mkoffset(ftl, zone_num, block, 0);
 469	erase.len = ftl->block_size;
 470	erase.priv = (u_long)ftl;
 471
 472	if (ftl->unstable)
 473		return -EIO;
 474
 475	BUG_ON(ftl->readonly);
 476
 477	if (zone_num == 0 && (block == ftl->cis_block || block == 0)) {
 478		sm_printk("attempted to erase the CIS!");
 479		return -EIO;
 480	}
 481
 482	if (mtd->erase(mtd, &erase)) {
 483		sm_printk("erase of block %d in zone %d failed",
 484							block, zone_num);
 485		goto error;
 486	}
 487
 488	if (erase.state == MTD_ERASE_PENDING)
 489		wait_for_completion(&ftl->erase_completion);
 490
 491	if (erase.state != MTD_ERASE_DONE) {
 492		sm_printk("erase of block %d in zone %d failed after wait",
 493			block, zone_num);
 494		goto error;
 495	}
 496
 497	if (put_free)
 498		kfifo_in(&zone->free_sectors,
 499			(const unsigned char *)&block, sizeof(block));
 500
 501	return 0;
 502error:
 503	sm_mark_block_bad(ftl, zone_num, block);
 504	return -EIO;
 505}
 506
 507static void sm_erase_callback(struct erase_info *self)
 508{
 509	struct sm_ftl *ftl = (struct sm_ftl *)self->priv;
 510	complete(&ftl->erase_completion);
 511}
 512
 513/* Throughtly test that block is valid. */
 514static int sm_check_block(struct sm_ftl *ftl, int zone, int block)
 515{
 516	int boffset;
 517	struct sm_oob oob;
 518	int lbas[] = { -3, 0, 0, 0 };
 519	int i = 0;
 520	int test_lba;
 521
 522
 523	/* First just check that block doesn't look fishy */
 524	/* Only blocks that are valid or are sliced in two parts, are
 525		accepted */
 526	for (boffset = 0; boffset < ftl->block_size;
 527					boffset += SM_SECTOR_SIZE) {
 528
 529		/* This shoudn't happen anyway */
 530		if (sm_read_sector(ftl, zone, block, boffset, NULL, &oob))
 531			return -2;
 532
 533		test_lba = sm_read_lba(&oob);
 534
 535		if (lbas[i] != test_lba)
 536			lbas[++i] = test_lba;
 537
 538		/* If we found three different LBAs, something is fishy */
 539		if (i == 3)
 540			return -EIO;
 541	}
 542
 543	/* If the block is sliced (partially erased usually) erase it */
 544	if (i == 2) {
 545		sm_erase_block(ftl, zone, block, 1);
 546		return 1;
 547	}
 548
 549	return 0;
 550}
 551
 552/* ----------------- media scanning --------------------------------- */
 553static const struct chs_entry chs_table[] = {
 554	{ 1,    125,  4,  4  },
 555	{ 2,    125,  4,  8  },
 556	{ 4,    250,  4,  8  },
 557	{ 8,    250,  4,  16 },
 558	{ 16,   500,  4,  16 },
 559	{ 32,   500,  8,  16 },
 560	{ 64,   500,  8,  32 },
 561	{ 128,  500,  16, 32 },
 562	{ 256,  1000, 16, 32 },
 563	{ 512,  1015, 32, 63 },
 564	{ 1024, 985,  33, 63 },
 565	{ 2048, 985,  33, 63 },
 566	{ 0 },
 567};
 568
 569
 570static const uint8_t cis_signature[] = {
 571	0x01, 0x03, 0xD9, 0x01, 0xFF, 0x18, 0x02, 0xDF, 0x01, 0x20
 572};
 573/* Find out media parameters.
 574 * This ideally has to be based on nand id, but for now device size is enough */
 575int sm_get_media_info(struct sm_ftl *ftl, struct mtd_info *mtd)
 576{
 577	int i;
 578	int size_in_megs = mtd->size / (1024 * 1024);
 579
 580	ftl->readonly = mtd->type == MTD_ROM;
 581
 582	/* Manual settings for very old devices */
 583	ftl->zone_count = 1;
 584	ftl->smallpagenand = 0;
 585
 586	switch (size_in_megs) {
 587	case 1:
 588		/* 1 MiB flash/rom SmartMedia card (256 byte pages)*/
 589		ftl->zone_size = 256;
 590		ftl->max_lba = 250;
 591		ftl->block_size = 8 * SM_SECTOR_SIZE;
 592		ftl->smallpagenand = 1;
 593
 594		break;
 595	case 2:
 596		/* 2 MiB flash SmartMedia (256 byte pages)*/
 597		if (mtd->writesize == SM_SMALL_PAGE) {
 598			ftl->zone_size = 512;
 599			ftl->max_lba = 500;
 600			ftl->block_size = 8 * SM_SECTOR_SIZE;
 601			ftl->smallpagenand = 1;
 602		/* 2 MiB rom SmartMedia */
 603		} else {
 604
 605			if (!ftl->readonly)
 606				return -ENODEV;
 607
 608			ftl->zone_size = 256;
 609			ftl->max_lba = 250;
 610			ftl->block_size = 16 * SM_SECTOR_SIZE;
 611		}
 612		break;
 613	case 4:
 614		/* 4 MiB flash/rom SmartMedia device */
 615		ftl->zone_size = 512;
 616		ftl->max_lba = 500;
 617		ftl->block_size = 16 * SM_SECTOR_SIZE;
 618		break;
 619	case 8:
 620		/* 8 MiB flash/rom SmartMedia device */
 621		ftl->zone_size = 1024;
 622		ftl->max_lba = 1000;
 623		ftl->block_size = 16 * SM_SECTOR_SIZE;
 624	}
 625
 626	/* Minimum xD size is 16MiB. Also, all xD cards have standard zone
 627	   sizes. SmartMedia cards exist up to 128 MiB and have same layout*/
 628	if (size_in_megs >= 16) {
 629		ftl->zone_count = size_in_megs / 16;
 630		ftl->zone_size = 1024;
 631		ftl->max_lba = 1000;
 632		ftl->block_size = 32 * SM_SECTOR_SIZE;
 633	}
 634
 635	/* Test for proper write,erase and oob sizes */
 636	if (mtd->erasesize > ftl->block_size)
 637		return -ENODEV;
 638
 639	if (mtd->writesize > SM_SECTOR_SIZE)
 640		return -ENODEV;
 641
 642	if (ftl->smallpagenand && mtd->oobsize < SM_SMALL_OOB_SIZE)
 643		return -ENODEV;
 644
 645	if (!ftl->smallpagenand && mtd->oobsize < SM_OOB_SIZE)
 646		return -ENODEV;
 647
 648	/* We use these functions for IO */
 649	if (!mtd->read_oob || !mtd->write_oob)
 650		return -ENODEV;
 651
 652	/* Find geometry information */
 653	for (i = 0 ; i < ARRAY_SIZE(chs_table) ; i++) {
 654		if (chs_table[i].size == size_in_megs) {
 655			ftl->cylinders = chs_table[i].cyl;
 656			ftl->heads = chs_table[i].head;
 657			ftl->sectors = chs_table[i].sec;
 658			return 0;
 659		}
 660	}
 661
 662	sm_printk("media has unknown size : %dMiB", size_in_megs);
 663	ftl->cylinders = 985;
 664	ftl->heads =  33;
 665	ftl->sectors = 63;
 666	return 0;
 667}
 668
 669/* Validate the CIS */
 670static int sm_read_cis(struct sm_ftl *ftl)
 671{
 672	struct sm_oob oob;
 673
 674	if (sm_read_sector(ftl,
 675		0, ftl->cis_block, ftl->cis_boffset, ftl->cis_buffer, &oob))
 676			return -EIO;
 677
 678	if (!sm_sector_valid(&oob) || !sm_block_valid(&oob))
 679		return -EIO;
 680
 681	if (!memcmp(ftl->cis_buffer + ftl->cis_page_offset,
 682			cis_signature, sizeof(cis_signature))) {
 683		return 0;
 684	}
 685
 686	return -EIO;
 687}
 688
 689/* Scan the media for the CIS */
 690static int sm_find_cis(struct sm_ftl *ftl)
 691{
 692	struct sm_oob oob;
 693	int block, boffset;
 694	int block_found = 0;
 695	int cis_found = 0;
 696
 697	/* Search for first valid block */
 698	for (block = 0 ; block < ftl->zone_size - ftl->max_lba ; block++) {
 699
 700		if (sm_read_sector(ftl, 0, block, 0, NULL, &oob))
 701			continue;
 702
 703		if (!sm_block_valid(&oob))
 704			continue;
 705		block_found = 1;
 706		break;
 707	}
 708
 709	if (!block_found)
 710		return -EIO;
 711
 712	/* Search for first valid sector in this block */
 713	for (boffset = 0 ; boffset < ftl->block_size;
 714						boffset += SM_SECTOR_SIZE) {
 715
 716		if (sm_read_sector(ftl, 0, block, boffset, NULL, &oob))
 717			continue;
 718
 719		if (!sm_sector_valid(&oob))
 720			continue;
 721		break;
 722	}
 723
 724	if (boffset == ftl->block_size)
 725		return -EIO;
 726
 727	ftl->cis_block = block;
 728	ftl->cis_boffset = boffset;
 729	ftl->cis_page_offset = 0;
 730
 731	cis_found = !sm_read_cis(ftl);
 732
 733	if (!cis_found) {
 734		ftl->cis_page_offset = SM_SMALL_PAGE;
 735		cis_found = !sm_read_cis(ftl);
 736	}
 737
 738	if (cis_found) {
 739		dbg("CIS block found at offset %x",
 740			block * ftl->block_size +
 741				boffset + ftl->cis_page_offset);
 742		return 0;
 743	}
 744	return -EIO;
 745}
 746
 747/* Basic test to determine if underlying mtd device if functional */
 748static int sm_recheck_media(struct sm_ftl *ftl)
 749{
 750	if (sm_read_cis(ftl)) {
 751
 752		if (!ftl->unstable) {
 753			sm_printk("media unstable, not allowing writes");
 754			ftl->unstable = 1;
 755		}
 756		return -EIO;
 757	}
 758	return 0;
 759}
 760
 761/* Initialize a FTL zone */
 762static int sm_init_zone(struct sm_ftl *ftl, int zone_num)
 763{
 764	struct ftl_zone *zone = &ftl->zones[zone_num];
 765	struct sm_oob oob;
 766	uint16_t block;
 767	int lba;
 768	int i = 0;
 769	int len;
 770
 771	dbg("initializing zone %d", zone_num);
 772
 773	/* Allocate memory for FTL table */
 774	zone->lba_to_phys_table = kmalloc(ftl->max_lba * 2, GFP_KERNEL);
 775
 776	if (!zone->lba_to_phys_table)
 777		return -ENOMEM;
 778	memset(zone->lba_to_phys_table, -1, ftl->max_lba * 2);
 779
 780
 781	/* Allocate memory for free sectors FIFO */
 782	if (kfifo_alloc(&zone->free_sectors, ftl->zone_size * 2, GFP_KERNEL)) {
 783		kfree(zone->lba_to_phys_table);
 784		return -ENOMEM;
 785	}
 786
 787	/* Now scan the zone */
 788	for (block = 0 ; block < ftl->zone_size ; block++) {
 789
 790		/* Skip blocks till the CIS (including) */
 791		if (zone_num == 0 && block <= ftl->cis_block)
 792			continue;
 793
 794		/* Read the oob of first sector */
 795		if (sm_read_sector(ftl, zone_num, block, 0, NULL, &oob))
 796			return -EIO;
 797
 798		/* Test to see if block is erased. It is enough to test
 799			first sector, because erase happens in one shot */
 800		if (sm_block_erased(&oob)) {
 801			kfifo_in(&zone->free_sectors,
 802				(unsigned char *)&block, 2);
 803			continue;
 804		}
 805
 806		/* If block is marked as bad, skip it */
 807		/* This assumes we can trust first sector*/
 808		/* However the way the block valid status is defined, ensures
 809			very low probability of failure here */
 810		if (!sm_block_valid(&oob)) {
 811			dbg("PH %04d <-> <marked bad>", block);
 812			continue;
 813		}
 814
 815
 816		lba = sm_read_lba(&oob);
 817
 818		/* Invalid LBA means that block is damaged. */
 819		/* We can try to erase it, or mark it as bad, but
 820			lets leave that to recovery application */
 821		if (lba == -2 || lba >= ftl->max_lba) {
 822			dbg("PH %04d <-> LBA %04d(bad)", block, lba);
 823			continue;
 824		}
 825
 826
 827		/* If there is no collision,
 828			just put the sector in the FTL table */
 829		if (zone->lba_to_phys_table[lba] < 0) {
 830			dbg_verbose("PH %04d <-> LBA %04d", block, lba);
 831			zone->lba_to_phys_table[lba] = block;
 832			continue;
 833		}
 834
 835		sm_printk("collision"
 836			" of LBA %d between blocks %d and %d in zone %d",
 837			lba, zone->lba_to_phys_table[lba], block, zone_num);
 838
 839		/* Test that this block is valid*/
 840		if (sm_check_block(ftl, zone_num, block))
 841			continue;
 842
 843		/* Test now the old block */
 844		if (sm_check_block(ftl, zone_num,
 845					zone->lba_to_phys_table[lba])) {
 846			zone->lba_to_phys_table[lba] = block;
 847			continue;
 848		}
 849
 850		/* If both blocks are valid and share same LBA, it means that
 851			they hold different versions of same data. It not
 852			known which is more recent, thus just erase one of them
 853		*/
 854		sm_printk("both blocks are valid, erasing the later");
 855		sm_erase_block(ftl, zone_num, block, 1);
 856	}
 857
 858	dbg("zone initialized");
 859	zone->initialized = 1;
 860
 861	/* No free sectors, means that the zone is heavily damaged, write won't
 862		work, but it can still can be (partially) read */
 863	if (!kfifo_len(&zone->free_sectors)) {
 864		sm_printk("no free blocks in zone %d", zone_num);
 865		return 0;
 866	}
 867
 868	/* Randomize first block we write to */
 869	get_random_bytes(&i, 2);
 870	i %= (kfifo_len(&zone->free_sectors) / 2);
 871
 872	while (i--) {
 873		len = kfifo_out(&zone->free_sectors,
 874					(unsigned char *)&block, 2);
 875		WARN_ON(len != 2);
 876		kfifo_in(&zone->free_sectors, (const unsigned char *)&block, 2);
 877	}
 878	return 0;
 879}
 880
 881/* Get and automatically initialize an FTL mapping for one zone */
 882struct ftl_zone *sm_get_zone(struct sm_ftl *ftl, int zone_num)
 883{
 884	struct ftl_zone *zone;
 885	int error;
 886
 887	BUG_ON(zone_num >= ftl->zone_count);
 888	zone = &ftl->zones[zone_num];
 889
 890	if (!zone->initialized) {
 891		error = sm_init_zone(ftl, zone_num);
 892
 893		if (error)
 894			return ERR_PTR(error);
 895	}
 896	return zone;
 897}
 898
 899
 900/* ----------------- cache handling ------------------------------------------*/
 901
 902/* Initialize the one block cache */
 903void sm_cache_init(struct sm_ftl *ftl)
 904{
 905	ftl->cache_data_invalid_bitmap = 0xFFFFFFFF;
 906	ftl->cache_clean = 1;
 907	ftl->cache_zone = -1;
 908	ftl->cache_block = -1;
 909	/*memset(ftl->cache_data, 0xAA, ftl->block_size);*/
 910}
 911
 912/* Put sector in one block cache */
 913void sm_cache_put(struct sm_ftl *ftl, char *buffer, int boffset)
 914{
 915	memcpy(ftl->cache_data + boffset, buffer, SM_SECTOR_SIZE);
 916	clear_bit(boffset / SM_SECTOR_SIZE, &ftl->cache_data_invalid_bitmap);
 917	ftl->cache_clean = 0;
 918}
 919
 920/* Read a sector from the cache */
 921int sm_cache_get(struct sm_ftl *ftl, char *buffer, int boffset)
 922{
 923	if (test_bit(boffset / SM_SECTOR_SIZE,
 924		&ftl->cache_data_invalid_bitmap))
 925			return -1;
 926
 927	memcpy(buffer, ftl->cache_data + boffset, SM_SECTOR_SIZE);
 928	return 0;
 929}
 930
 931/* Write the cache to hardware */
 932int sm_cache_flush(struct sm_ftl *ftl)
 933{
 934	struct ftl_zone *zone;
 935
 936	int sector_num;
 937	uint16_t write_sector;
 938	int zone_num = ftl->cache_zone;
 939	int block_num;
 940
 941	if (ftl->cache_clean)
 942		return 0;
 943
 944	if (ftl->unstable)
 945		return -EIO;
 946
 947	BUG_ON(zone_num < 0);
 948	zone = &ftl->zones[zone_num];
 949	block_num = zone->lba_to_phys_table[ftl->cache_block];
 950
 951
 952	/* Try to read all unread areas of the cache block*/
 953	for_each_set_bit(sector_num, &ftl->cache_data_invalid_bitmap,
 954		ftl->block_size / SM_SECTOR_SIZE) {
 955
 956		if (!sm_read_sector(ftl,
 957			zone_num, block_num, sector_num * SM_SECTOR_SIZE,
 958			ftl->cache_data + sector_num * SM_SECTOR_SIZE, NULL))
 959				clear_bit(sector_num,
 960					&ftl->cache_data_invalid_bitmap);
 961	}
 962restart:
 963
 964	if (ftl->unstable)
 965		return -EIO;
 966
 967	/* If there are no spare blocks, */
 968	/* we could still continue by erasing/writing the current block,
 969		but for such worn out media it doesn't worth the trouble,
 970			and the dangers */
 971	if (kfifo_out(&zone->free_sectors,
 972				(unsigned char *)&write_sector, 2) != 2) {
 973		dbg("no free sectors for write!");
 974		return -EIO;
 975	}
 976
 977
 978	if (sm_write_block(ftl, ftl->cache_data, zone_num, write_sector,
 979		ftl->cache_block, ftl->cache_data_invalid_bitmap))
 980			goto restart;
 981
 982	/* Update the FTL table */
 983	zone->lba_to_phys_table[ftl->cache_block] = write_sector;
 984
 985	/* Write succesfull, so erase and free the old block */
 986	if (block_num > 0)
 987		sm_erase_block(ftl, zone_num, block_num, 1);
 988
 989	sm_cache_init(ftl);
 990	return 0;
 991}
 992
 993
 994/* flush timer, runs a second after last write */
 995static void sm_cache_flush_timer(unsigned long data)
 996{
 997	struct sm_ftl *ftl = (struct sm_ftl *)data;
 998	queue_work(cache_flush_workqueue, &ftl->flush_work);
 999}
1000
1001/* cache flush work, kicked by timer */
1002static void sm_cache_flush_work(struct work_struct *work)
1003{
1004	struct sm_ftl *ftl = container_of(work, struct sm_ftl, flush_work);
1005	mutex_lock(&ftl->mutex);
1006	sm_cache_flush(ftl);
1007	mutex_unlock(&ftl->mutex);
1008	return;
1009}
1010
1011/* ---------------- outside interface -------------------------------------- */
1012
1013/* outside interface: read a sector */
1014static int sm_read(struct mtd_blktrans_dev *dev,
1015		   unsigned long sect_no, char *buf)
1016{
1017	struct sm_ftl *ftl = dev->priv;
1018	struct ftl_zone *zone;
1019	int error = 0, in_cache = 0;
1020	int zone_num, block, boffset;
1021
1022	sm_break_offset(ftl, sect_no << 9, &zone_num, &block, &boffset);
1023	mutex_lock(&ftl->mutex);
1024
1025
1026	zone = sm_get_zone(ftl, zone_num);
1027	if (IS_ERR(zone)) {
1028		error = PTR_ERR(zone);
1029		goto unlock;
1030	}
1031
1032	/* Have to look at cache first */
1033	if (ftl->cache_zone == zone_num && ftl->cache_block == block) {
1034		in_cache = 1;
1035		if (!sm_cache_get(ftl, buf, boffset))
1036			goto unlock;
1037	}
1038
1039	/* Translate the block and return if doesn't exist in the table */
1040	block = zone->lba_to_phys_table[block];
1041
1042	if (block == -1) {
1043		memset(buf, 0xFF, SM_SECTOR_SIZE);
1044		goto unlock;
1045	}
1046
1047	if (sm_read_sector(ftl, zone_num, block, boffset, buf, NULL)) {
1048		error = -EIO;
1049		goto unlock;
1050	}
1051
1052	if (in_cache)
1053		sm_cache_put(ftl, buf, boffset);
1054unlock:
1055	mutex_unlock(&ftl->mutex);
1056	return error;
1057}
1058
1059/* outside interface: write a sector */
1060static int sm_write(struct mtd_blktrans_dev *dev,
1061				unsigned long sec_no, char *buf)
1062{
1063	struct sm_ftl *ftl = dev->priv;
1064	struct ftl_zone *zone;
1065	int error, zone_num, block, boffset;
1066
1067	BUG_ON(ftl->readonly);
1068	sm_break_offset(ftl, sec_no << 9, &zone_num, &block, &boffset);
1069
1070	/* No need in flush thread running now */
1071	del_timer(&ftl->timer);
1072	mutex_lock(&ftl->mutex);
1073
1074	zone = sm_get_zone(ftl, zone_num);
1075	if (IS_ERR(zone)) {
1076		error = PTR_ERR(zone);
1077		goto unlock;
1078	}
1079
1080	/* If entry is not in cache, flush it */
1081	if (ftl->cache_block != block || ftl->cache_zone != zone_num) {
1082
1083		error = sm_cache_flush(ftl);
1084		if (error)
1085			goto unlock;
1086
1087		ftl->cache_block = block;
1088		ftl->cache_zone = zone_num;
1089	}
1090
1091	sm_cache_put(ftl, buf, boffset);
1092unlock:
1093	mod_timer(&ftl->timer, jiffies + msecs_to_jiffies(cache_timeout));
1094	mutex_unlock(&ftl->mutex);
1095	return error;
1096}
1097
1098/* outside interface: flush everything */
1099static int sm_flush(struct mtd_blktrans_dev *dev)
1100{
1101	struct sm_ftl *ftl = dev->priv;
1102	int retval;
1103
1104	mutex_lock(&ftl->mutex);
1105	retval =  sm_cache_flush(ftl);
1106	mutex_unlock(&ftl->mutex);
1107	return retval;
1108}
1109
1110/* outside interface: device is released */
1111static int sm_release(struct mtd_blktrans_dev *dev)
1112{
1113	struct sm_ftl *ftl = dev->priv;
1114
1115	mutex_lock(&ftl->mutex);
1116	del_timer_sync(&ftl->timer);
1117	cancel_work_sync(&ftl->flush_work);
1118	sm_cache_flush(ftl);
1119	mutex_unlock(&ftl->mutex);
1120	return 0;
1121}
1122
1123/* outside interface: get geometry */
1124static int sm_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
1125{
1126	struct sm_ftl *ftl = dev->priv;
1127	geo->heads = ftl->heads;
1128	geo->sectors = ftl->sectors;
1129	geo->cylinders = ftl->cylinders;
1130	return 0;
1131}
1132
1133/* external interface: main initialization function */
1134static void sm_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
1135{
1136	struct mtd_blktrans_dev *trans;
1137	struct sm_ftl *ftl;
1138
1139	/* Allocate & initialize our private structure */
1140	ftl = kzalloc(sizeof(struct sm_ftl), GFP_KERNEL);
1141	if (!ftl)
1142		goto error1;
1143
1144
1145	mutex_init(&ftl->mutex);
1146	setup_timer(&ftl->timer, sm_cache_flush_timer, (unsigned long)ftl);
1147	INIT_WORK(&ftl->flush_work, sm_cache_flush_work);
1148	init_completion(&ftl->erase_completion);
1149
1150	/* Read media information */
1151	if (sm_get_media_info(ftl, mtd)) {
1152		dbg("found unsupported mtd device, aborting");
1153		goto error2;
1154	}
1155
1156
1157	/* Allocate temporary CIS buffer for read retry support */
1158	ftl->cis_buffer = kzalloc(SM_SECTOR_SIZE, GFP_KERNEL);
1159	if (!ftl->cis_buffer)
1160		goto error2;
1161
1162	/* Allocate zone array, it will be initialized on demand */
1163	ftl->zones = kzalloc(sizeof(struct ftl_zone) * ftl->zone_count,
1164								GFP_KERNEL);
1165	if (!ftl->zones)
1166		goto error3;
1167
1168	/* Allocate the cache*/
1169	ftl->cache_data = kzalloc(ftl->block_size, GFP_KERNEL);
1170
1171	if (!ftl->cache_data)
1172		goto error4;
1173
1174	sm_cache_init(ftl);
1175
1176
1177	/* Allocate upper layer structure and initialize it */
1178	trans = kzalloc(sizeof(struct mtd_blktrans_dev), GFP_KERNEL);
1179	if (!trans)
1180		goto error5;
1181
1182	ftl->trans = trans;
1183	trans->priv = ftl;
1184
1185	trans->tr = tr;
1186	trans->mtd = mtd;
1187	trans->devnum = -1;
1188	trans->size = (ftl->block_size * ftl->max_lba * ftl->zone_count) >> 9;
1189	trans->readonly = ftl->readonly;
1190
1191	if (sm_find_cis(ftl)) {
1192		dbg("CIS not found on mtd device, aborting");
1193		goto error6;
1194	}
1195
1196	ftl->disk_attributes = sm_create_sysfs_attributes(ftl);
1197	if (!ftl->disk_attributes)
1198		goto error6;
1199	trans->disk_attributes = ftl->disk_attributes;
1200
1201	sm_printk("Found %d MiB xD/SmartMedia FTL on mtd%d",
1202		(int)(mtd->size / (1024 * 1024)), mtd->index);
1203
1204	dbg("FTL layout:");
1205	dbg("%d zone(s), each consists of %d blocks (+%d spares)",
1206		ftl->zone_count, ftl->max_lba,
1207		ftl->zone_size - ftl->max_lba);
1208	dbg("each block consists of %d bytes",
1209		ftl->block_size);
1210
1211
1212	/* Register device*/
1213	if (add_mtd_blktrans_dev(trans)) {
1214		dbg("error in mtdblktrans layer");
1215		goto error6;
1216	}
1217	return;
1218error6:
1219	kfree(trans);
1220error5:
1221	kfree(ftl->cache_data);
1222error4:
1223	kfree(ftl->zones);
1224error3:
1225	kfree(ftl->cis_buffer);
1226error2:
1227	kfree(ftl);
1228error1:
1229	return;
1230}
1231
1232/* main interface: device {surprise,} removal */
1233static void sm_remove_dev(struct mtd_blktrans_dev *dev)
1234{
1235	struct sm_ftl *ftl = dev->priv;
1236	int i;
1237
1238	del_mtd_blktrans_dev(dev);
1239	ftl->trans = NULL;
1240
1241	for (i = 0 ; i < ftl->zone_count; i++) {
1242
1243		if (!ftl->zones[i].initialized)
1244			continue;
1245
1246		kfree(ftl->zones[i].lba_to_phys_table);
1247		kfifo_free(&ftl->zones[i].free_sectors);
1248	}
1249
1250	sm_delete_sysfs_attributes(ftl);
1251	kfree(ftl->cis_buffer);
1252	kfree(ftl->zones);
1253	kfree(ftl->cache_data);
1254	kfree(ftl);
1255}
1256
1257static struct mtd_blktrans_ops sm_ftl_ops = {
1258	.name		= "smblk",
1259	.major		= -1,
1260	.part_bits	= SM_FTL_PARTN_BITS,
1261	.blksize	= SM_SECTOR_SIZE,
1262	.getgeo		= sm_getgeo,
1263
1264	.add_mtd	= sm_add_mtd,
1265	.remove_dev	= sm_remove_dev,
1266
1267	.readsect	= sm_read,
1268	.writesect	= sm_write,
1269
1270	.flush		= sm_flush,
1271	.release	= sm_release,
1272
1273	.owner		= THIS_MODULE,
1274};
1275
1276static __init int sm_module_init(void)
1277{
1278	int error = 0;
1279	cache_flush_workqueue = create_freezable_workqueue("smflush");
1280
1281	if (IS_ERR(cache_flush_workqueue))
1282		return PTR_ERR(cache_flush_workqueue);
1283
1284	error = register_mtd_blktrans(&sm_ftl_ops);
1285	if (error)
1286		destroy_workqueue(cache_flush_workqueue);
1287	return error;
1288
1289}
1290
1291static void __exit sm_module_exit(void)
1292{
1293	destroy_workqueue(cache_flush_workqueue);
1294	deregister_mtd_blktrans(&sm_ftl_ops);
1295}
1296
1297module_init(sm_module_init);
1298module_exit(sm_module_exit);
1299
1300MODULE_LICENSE("GPL");
1301MODULE_AUTHOR("Maxim Levitsky <maximlevitsky@gmail.com>");
1302MODULE_DESCRIPTION("Smartmedia/xD mtd translation layer");