1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright © 2009 - Maxim Levitsky
   4 * SmartMedia/xD translation layer
   5 */
   6
   7#include <linux/kernel.h>
   8#include <linux/module.h>
   9#include <linux/random.h>
  10#include <linux/hdreg.h>
  11#include <linux/kthread.h>
  12#include <linux/freezer.h>
  13#include <linux/sysfs.h>
  14#include <linux/bitops.h>
  15#include <linux/slab.h>
  16#include <linux/mtd/nand-ecc-sw-hamming.h>
  17#include "nand/raw/sm_common.h"
  18#include "sm_ftl.h"
  19
  20
  21
  22static struct workqueue_struct *cache_flush_workqueue;
  23
  24static int cache_timeout = 1000;
  25module_param(cache_timeout, int, S_IRUGO);
  26MODULE_PARM_DESC(cache_timeout,
  27	"Timeout (in ms) for cache flush (1000 ms default");
  28
  29static int debug;
  30module_param(debug, int, S_IRUGO | S_IWUSR);
  31MODULE_PARM_DESC(debug, "Debug level (0-2)");
  32
  33
  34/* ------------------- sysfs attributes ---------------------------------- */
  35struct sm_sysfs_attribute {
  36	struct device_attribute dev_attr;
  37	char *data;
  38	int len;
  39};
  40
  41static ssize_t sm_attr_show(struct device *dev, struct device_attribute *attr,
  42		     char *buf)
  43{
  44	struct sm_sysfs_attribute *sm_attr =
  45		container_of(attr, struct sm_sysfs_attribute, dev_attr);
  46
  47	strncpy(buf, sm_attr->data, sm_attr->len);
  48	return sm_attr->len;
  49}
  50
  51
  52#define NUM_ATTRIBUTES 1
  53#define SM_CIS_VENDOR_OFFSET 0x59
  54static struct attribute_group *sm_create_sysfs_attributes(struct sm_ftl *ftl)
  55{
  56	struct attribute_group *attr_group;
  57	struct attribute **attributes;
  58	struct sm_sysfs_attribute *vendor_attribute;
  59	char *vendor;
  60
  61	vendor = kstrndup(ftl->cis_buffer + SM_CIS_VENDOR_OFFSET,
  62			  SM_SMALL_PAGE - SM_CIS_VENDOR_OFFSET, GFP_KERNEL);
  63	if (!vendor)
  64		goto error1;
  65
  66	/* Initialize sysfs attributes */
  67	vendor_attribute =
  68		kzalloc(sizeof(struct sm_sysfs_attribute), GFP_KERNEL);
  69	if (!vendor_attribute)
  70		goto error2;
  71
  72	sysfs_attr_init(&vendor_attribute->dev_attr.attr);
  73
  74	vendor_attribute->data = vendor;
  75	vendor_attribute->len = strlen(vendor);
  76	vendor_attribute->dev_attr.attr.name = "vendor";
  77	vendor_attribute->dev_attr.attr.mode = S_IRUGO;
  78	vendor_attribute->dev_attr.show = sm_attr_show;
  79
  80
  81	/* Create array of pointers to the attributes */
  82	attributes = kcalloc(NUM_ATTRIBUTES + 1, sizeof(struct attribute *),
  83								GFP_KERNEL);
  84	if (!attributes)
  85		goto error3;
  86	attributes[0] = &vendor_attribute->dev_attr.attr;
  87
  88	/* Finally create the attribute group */
  89	attr_group = kzalloc(sizeof(struct attribute_group), GFP_KERNEL);
  90	if (!attr_group)
  91		goto error4;
  92	attr_group->attrs = attributes;
  93	return attr_group;
  94error4:
  95	kfree(attributes);
  96error3:
  97	kfree(vendor_attribute);
  98error2:
  99	kfree(vendor);
 100error1:
 101	return NULL;
 102}
 103
 104static void sm_delete_sysfs_attributes(struct sm_ftl *ftl)
 105{
 106	struct attribute **attributes = ftl->disk_attributes->attrs;
 107	int i;
 108
 109	for (i = 0; attributes[i] ; i++) {
 110
 111		struct device_attribute *dev_attr = container_of(attributes[i],
 112			struct device_attribute, attr);
 113
 114		struct sm_sysfs_attribute *sm_attr =
 115			container_of(dev_attr,
 116				struct sm_sysfs_attribute, dev_attr);
 117
 118		kfree(sm_attr->data);
 119		kfree(sm_attr);
 120	}
 121
 122	kfree(ftl->disk_attributes->attrs);
 123	kfree(ftl->disk_attributes);
 124}
 125
 126
 127/* ----------------------- oob helpers -------------------------------------- */
 128
 129static int sm_get_lba(uint8_t *lba)
 130{
 131	/* check fixed bits */
 132	if ((lba[0] & 0xF8) != 0x10)
 133		return -2;
 134
 135	/* check parity - endianness doesn't matter */
 136	if (hweight16(*(uint16_t *)lba) & 1)
 137		return -2;
 138
 139	return (lba[1] >> 1) | ((lba[0] & 0x07) << 7);
 140}
 141
 142
 143/*
 144 * Read LBA associated with block
 145 * returns -1, if block is erased
 146 * returns -2 if error happens
 147 */
 148static int sm_read_lba(struct sm_oob *oob)
 149{
 150	static const uint32_t erased_pattern[4] = {
 151		0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
 152
 153	uint16_t lba_test;
 154	int lba;
 155
 156	/* First test for erased block */
 157	if (!memcmp(oob, erased_pattern, SM_OOB_SIZE))
 158		return -1;
 159
 160	/* Now check is both copies of the LBA differ too much */
 161	lba_test = *(uint16_t *)oob->lba_copy1 ^ *(uint16_t*)oob->lba_copy2;
 162	if (lba_test && !is_power_of_2(lba_test))
 163		return -2;
 164
 165	/* And read it */
 166	lba = sm_get_lba(oob->lba_copy1);
 167
 168	if (lba == -2)
 169		lba = sm_get_lba(oob->lba_copy2);
 170
 171	return lba;
 172}
 173
 174static void sm_write_lba(struct sm_oob *oob, uint16_t lba)
 175{
 176	uint8_t tmp[2];
 177
 178	WARN_ON(lba >= 1000);
 179
 180	tmp[0] = 0x10 | ((lba >> 7) & 0x07);
 181	tmp[1] = (lba << 1) & 0xFF;
 182
 183	if (hweight16(*(uint16_t *)tmp) & 0x01)
 184		tmp[1] |= 1;
 185
 186	oob->lba_copy1[0] = oob->lba_copy2[0] = tmp[0];
 187	oob->lba_copy1[1] = oob->lba_copy2[1] = tmp[1];
 188}
 189
 190
 191/* Make offset from parts */
 192static loff_t sm_mkoffset(struct sm_ftl *ftl, int zone, int block, int boffset)
 193{
 194	WARN_ON(boffset & (SM_SECTOR_SIZE - 1));
 195	WARN_ON(zone < 0 || zone >= ftl->zone_count);
 196	WARN_ON(block >= ftl->zone_size);
 197	WARN_ON(boffset >= ftl->block_size);
 198
 199	if (block == -1)
 200		return -1;
 201
 202	return (zone * SM_MAX_ZONE_SIZE + block) * ftl->block_size + boffset;
 203}
 204
 205/* Breaks offset into parts */
 206static void sm_break_offset(struct sm_ftl *ftl, loff_t loffset,
 207			    int *zone, int *block, int *boffset)
 208{
 209	u64 offset = loffset;
 210	*boffset = do_div(offset, ftl->block_size);
 211	*block = do_div(offset, ftl->max_lba);
 212	*zone = offset >= ftl->zone_count ? -1 : offset;
 213}
 214
 215/* ---------------------- low level IO ------------------------------------- */
 216
 217static int sm_correct_sector(uint8_t *buffer, struct sm_oob *oob)
 218{
 219	bool sm_order = IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC);
 220	uint8_t ecc[3];
 221
 222	ecc_sw_hamming_calculate(buffer, SM_SMALL_PAGE, ecc, sm_order);
 223	if (ecc_sw_hamming_correct(buffer, ecc, oob->ecc1, SM_SMALL_PAGE,
 224				   sm_order) < 0)
 225		return -EIO;
 226
 227	buffer += SM_SMALL_PAGE;
 228
 229	ecc_sw_hamming_calculate(buffer, SM_SMALL_PAGE, ecc, sm_order);
 230	if (ecc_sw_hamming_correct(buffer, ecc, oob->ecc2, SM_SMALL_PAGE,
 231				   sm_order) < 0)
 232		return -EIO;
 233	return 0;
 234}
 235
 236/* Reads a sector + oob*/
 237static int sm_read_sector(struct sm_ftl *ftl,
 238			  int zone, int block, int boffset,
 239			  uint8_t *buffer, struct sm_oob *oob)
 240{
 241	struct mtd_info *mtd = ftl->trans->mtd;
 242	struct mtd_oob_ops ops = { };
 243	struct sm_oob tmp_oob;
 244	int ret = -EIO;
 245	int try = 0;
 246
 247	/* FTL can contain -1 entries that are by default filled with bits */
 248	if (block == -1) {
 249		if (buffer)
 250			memset(buffer, 0xFF, SM_SECTOR_SIZE);
 251		return 0;
 252	}
 253
 254	/* User might not need the oob, but we do for data verification */
 255	if (!oob)
 256		oob = &tmp_oob;
 257
 258	ops.mode = ftl->smallpagenand ? MTD_OPS_RAW : MTD_OPS_PLACE_OOB;
 259	ops.ooboffs = 0;
 260	ops.ooblen = SM_OOB_SIZE;
 261	ops.oobbuf = (void *)oob;
 262	ops.len = SM_SECTOR_SIZE;
 263	ops.datbuf = buffer;
 264
 265again:
 266	if (try++) {
 267		/* Avoid infinite recursion on CIS reads, sm_recheck_media
 268		 * won't help anyway
 269		 */
 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	/* Unfortunately, oob read will _always_ succeed,
 280	 * despite card removal.....
 281	 */
 282	ret = mtd_read_oob(mtd, sm_mkoffset(ftl, zone, block, boffset), &ops);
 283
 284	/* Test for unknown errors */
 285	if (ret != 0 && !mtd_is_bitflip_or_eccerr(ret)) {
 286		dbg("read of block %d at zone %d, failed due to error (%d)",
 287			block, zone, ret);
 288		goto again;
 289	}
 290
 291	/* Do a basic test on the oob, to guard against returned garbage */
 292	if (oob->reserved != 0xFFFFFFFF && !is_power_of_2(~oob->reserved))
 293		goto again;
 294
 295	/* This should never happen, unless there is a bug in the mtd driver */
 296	WARN_ON(ops.oobretlen != SM_OOB_SIZE);
 297	WARN_ON(buffer && ops.retlen != SM_SECTOR_SIZE);
 298
 299	if (!buffer)
 300		return 0;
 301
 302	/* Test if sector marked as bad */
 303	if (!sm_sector_valid(oob)) {
 304		dbg("read of block %d at zone %d, failed because it is marked"
 305			" as bad" , block, zone);
 306		goto again;
 307	}
 308
 309	/* Test ECC*/
 310	if (mtd_is_eccerr(ret) ||
 311		(ftl->smallpagenand && sm_correct_sector(buffer, oob))) {
 312
 313		dbg("read of block %d at zone %d, failed due to ECC error",
 314			block, zone);
 315		goto again;
 316	}
 317
 318	return 0;
 319}
 320
 321/* Writes a sector to media */
 322static int sm_write_sector(struct sm_ftl *ftl,
 323			   int zone, int block, int boffset,
 324			   uint8_t *buffer, struct sm_oob *oob)
 325{
 326	struct mtd_oob_ops ops = { };
 327	struct mtd_info *mtd = ftl->trans->mtd;
 328	int ret;
 329
 330	BUG_ON(ftl->readonly);
 331
 332	if (zone == 0 && (block == ftl->cis_block || block == 0)) {
 333		dbg("attempted to write the CIS!");
 334		return -EIO;
 335	}
 336
 337	if (ftl->unstable)
 338		return -EIO;
 339
 340	ops.mode = ftl->smallpagenand ? MTD_OPS_RAW : MTD_OPS_PLACE_OOB;
 341	ops.len = SM_SECTOR_SIZE;
 342	ops.datbuf = buffer;
 343	ops.ooboffs = 0;
 344	ops.ooblen = SM_OOB_SIZE;
 345	ops.oobbuf = (void *)oob;
 346
 347	ret = mtd_write_oob(mtd, sm_mkoffset(ftl, zone, block, boffset), &ops);
 348
 349	/* Now we assume that hardware will catch write bitflip errors */
 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	bool sm_order = IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC);
 374	struct sm_oob oob;
 375	int boffset;
 376	int retry = 0;
 377
 378	/* Initialize the oob with requested values */
 379	memset(&oob, 0xFF, SM_OOB_SIZE);
 380	sm_write_lba(&oob, lba);
 381restart:
 382	if (ftl->unstable)
 383		return -EIO;
 384
 385	for (boffset = 0; boffset < ftl->block_size;
 386				boffset += SM_SECTOR_SIZE) {
 387
 388		oob.data_status = 0xFF;
 389
 390		if (test_bit(boffset / SM_SECTOR_SIZE, &invalid_bitmap)) {
 391
 392			sm_printk("sector %d of block at LBA %d of zone %d"
 393				" couldn't be read, marking it as invalid",
 394				boffset / SM_SECTOR_SIZE, lba, zone);
 395
 396			oob.data_status = 0;
 397		}
 398
 399		if (ftl->smallpagenand) {
 400			ecc_sw_hamming_calculate(buf + boffset,
 401						 SM_SMALL_PAGE, oob.ecc1,
 402						 sm_order);
 403
 404			ecc_sw_hamming_calculate(buf + boffset + SM_SMALL_PAGE,
 405						 SM_SMALL_PAGE, oob.ecc2,
 406						 sm_order);
 407		}
 408		if (!sm_write_sector(ftl, zone, block, boffset,
 409							buf + boffset, &oob))
 410			continue;
 411
 412		if (!retry) {
 413
 414			/* If write fails. try to erase the block */
 415			/* This is safe, because we never write in blocks
 416			 * that contain valuable data.
 417			 * This is intended to repair block that are marked
 418			 * as erased, but that isn't fully erased
 419			 */
 420
 421			if (sm_erase_block(ftl, zone, block, 0))
 422				return -EIO;
 423
 424			retry = 1;
 425			goto restart;
 426		} else {
 427			sm_mark_block_bad(ftl, zone, block);
 428			return -EIO;
 429		}
 430	}
 431	return 0;
 432}
 433
 434
 435/* Mark whole block at offset 'offs' as bad. */
 436static void sm_mark_block_bad(struct sm_ftl *ftl, int zone, int block)
 437{
 438	struct sm_oob oob;
 439	int boffset;
 440
 441	memset(&oob, 0xFF, SM_OOB_SIZE);
 442	oob.block_status = 0xF0;
 443
 444	if (ftl->unstable)
 445		return;
 446
 447	if (sm_recheck_media(ftl))
 448		return;
 449
 450	sm_printk("marking block %d of zone %d as bad", block, zone);
 451
 452	/* We aren't checking the return value, because we don't care */
 453	/* This also fails on fake xD cards, but I guess these won't expose
 454	 * any bad blocks till fail completely
 455	 */
 456	for (boffset = 0; boffset < ftl->block_size; boffset += SM_SECTOR_SIZE)
 457		sm_write_sector(ftl, zone, block, boffset, NULL, &oob);
 458}
 459
 460/*
 461 * Erase a block within a zone
 462 * If erase succeeds, it updates free block fifo, otherwise marks block as bad
 463 */
 464static int sm_erase_block(struct sm_ftl *ftl, int zone_num, uint16_t block,
 465			  int put_free)
 466{
 467	struct ftl_zone *zone = &ftl->zones[zone_num];
 468	struct mtd_info *mtd = ftl->trans->mtd;
 469	struct erase_info erase;
 470
 471	erase.addr = sm_mkoffset(ftl, zone_num, block, 0);
 472	erase.len = ftl->block_size;
 473
 474	if (ftl->unstable)
 475		return -EIO;
 476
 477	BUG_ON(ftl->readonly);
 478
 479	if (zone_num == 0 && (block == ftl->cis_block || block == 0)) {
 480		sm_printk("attempted to erase the CIS!");
 481		return -EIO;
 482	}
 483
 484	if (mtd_erase(mtd, &erase)) {
 485		sm_printk("erase of block %d in zone %d failed",
 486							block, zone_num);
 487		goto error;
 488	}
 489
 490	if (put_free)
 491		kfifo_in(&zone->free_sectors,
 492			(const unsigned char *)&block, sizeof(block));
 493
 494	return 0;
 495error:
 496	sm_mark_block_bad(ftl, zone_num, block);
 497	return -EIO;
 498}
 499
 500/* Thoroughly test that block is valid. */
 501static int sm_check_block(struct sm_ftl *ftl, int zone, int block)
 502{
 503	int boffset;
 504	struct sm_oob oob;
 505	int lbas[] = { -3, 0, 0, 0 };
 506	int i = 0;
 507	int test_lba;
 508
 509
 510	/* First just check that block doesn't look fishy */
 511	/* Only blocks that are valid or are sliced in two parts, are
 512	 * accepted
 513	 */
 514	for (boffset = 0; boffset < ftl->block_size;
 515					boffset += SM_SECTOR_SIZE) {
 516
 517		/* This shouldn't happen anyway */
 518		if (sm_read_sector(ftl, zone, block, boffset, NULL, &oob))
 519			return -2;
 520
 521		test_lba = sm_read_lba(&oob);
 522
 523		if (lbas[i] != test_lba)
 524			lbas[++i] = test_lba;
 525
 526		/* If we found three different LBAs, something is fishy */
 527		if (i == 3)
 528			return -EIO;
 529	}
 530
 531	/* If the block is sliced (partially erased usually) erase it */
 532	if (i == 2) {
 533		sm_erase_block(ftl, zone, block, 1);
 534		return 1;
 535	}
 536
 537	return 0;
 538}
 539
 540/* ----------------- media scanning --------------------------------- */
 541static const struct chs_entry chs_table[] = {
 542	{ 1,    125,  4,  4  },
 543	{ 2,    125,  4,  8  },
 544	{ 4,    250,  4,  8  },
 545	{ 8,    250,  4,  16 },
 546	{ 16,   500,  4,  16 },
 547	{ 32,   500,  8,  16 },
 548	{ 64,   500,  8,  32 },
 549	{ 128,  500,  16, 32 },
 550	{ 256,  1000, 16, 32 },
 551	{ 512,  1015, 32, 63 },
 552	{ 1024, 985,  33, 63 },
 553	{ 2048, 985,  33, 63 },
 554	{ 0 },
 555};
 556
 557
 558static const uint8_t cis_signature[] = {
 559	0x01, 0x03, 0xD9, 0x01, 0xFF, 0x18, 0x02, 0xDF, 0x01, 0x20
 560};
 561/* Find out media parameters.
 562 * This ideally has to be based on nand id, but for now device size is enough
 563 */
 564static int sm_get_media_info(struct sm_ftl *ftl, struct mtd_info *mtd)
 565{
 566	int i;
 567	int size_in_megs = mtd->size / (1024 * 1024);
 568
 569	ftl->readonly = mtd->type == MTD_ROM;
 570
 571	/* Manual settings for very old devices */
 572	ftl->zone_count = 1;
 573	ftl->smallpagenand = 0;
 574
 575	switch (size_in_megs) {
 576	case 1:
 577		/* 1 MiB flash/rom SmartMedia card (256 byte pages)*/
 578		ftl->zone_size = 256;
 579		ftl->max_lba = 250;
 580		ftl->block_size = 8 * SM_SECTOR_SIZE;
 581		ftl->smallpagenand = 1;
 582
 583		break;
 584	case 2:
 585		/* 2 MiB flash SmartMedia (256 byte pages)*/
 586		if (mtd->writesize == SM_SMALL_PAGE) {
 587			ftl->zone_size = 512;
 588			ftl->max_lba = 500;
 589			ftl->block_size = 8 * SM_SECTOR_SIZE;
 590			ftl->smallpagenand = 1;
 591		/* 2 MiB rom SmartMedia */
 592		} else {
 593
 594			if (!ftl->readonly)
 595				return -ENODEV;
 596
 597			ftl->zone_size = 256;
 598			ftl->max_lba = 250;
 599			ftl->block_size = 16 * SM_SECTOR_SIZE;
 600		}
 601		break;
 602	case 4:
 603		/* 4 MiB flash/rom SmartMedia device */
 604		ftl->zone_size = 512;
 605		ftl->max_lba = 500;
 606		ftl->block_size = 16 * SM_SECTOR_SIZE;
 607		break;
 608	case 8:
 609		/* 8 MiB flash/rom SmartMedia device */
 610		ftl->zone_size = 1024;
 611		ftl->max_lba = 1000;
 612		ftl->block_size = 16 * SM_SECTOR_SIZE;
 613	}
 614
 615	/* Minimum xD size is 16MiB. Also, all xD cards have standard zone
 616	 * sizes. SmartMedia cards exist up to 128 MiB and have same layout
 617	 */
 618	if (size_in_megs >= 16) {
 619		ftl->zone_count = size_in_megs / 16;
 620		ftl->zone_size = 1024;
 621		ftl->max_lba = 1000;
 622		ftl->block_size = 32 * SM_SECTOR_SIZE;
 623	}
 624
 625	/* Test for proper write,erase and oob sizes */
 626	if (mtd->erasesize > ftl->block_size)
 627		return -ENODEV;
 628
 629	if (mtd->writesize > SM_SECTOR_SIZE)
 630		return -ENODEV;
 631
 632	if (ftl->smallpagenand && mtd->oobsize < SM_SMALL_OOB_SIZE)
 633		return -ENODEV;
 634
 635	if (!ftl->smallpagenand && mtd->oobsize < SM_OOB_SIZE)
 636		return -ENODEV;
 637
 638	/* We use OOB */
 639	if (!mtd_has_oob(mtd))
 640		return -ENODEV;
 641
 642	/* Find geometry information */
 643	for (i = 0 ; i < ARRAY_SIZE(chs_table) ; i++) {
 644		if (chs_table[i].size == size_in_megs) {
 645			ftl->cylinders = chs_table[i].cyl;
 646			ftl->heads = chs_table[i].head;
 647			ftl->sectors = chs_table[i].sec;
 648			return 0;
 649		}
 650	}
 651
 652	sm_printk("media has unknown size : %dMiB", size_in_megs);
 653	ftl->cylinders = 985;
 654	ftl->heads =  33;
 655	ftl->sectors = 63;
 656	return 0;
 657}
 658
 659/* Validate the CIS */
 660static int sm_read_cis(struct sm_ftl *ftl)
 661{
 662	struct sm_oob oob;
 663
 664	if (sm_read_sector(ftl,
 665		0, ftl->cis_block, ftl->cis_boffset, ftl->cis_buffer, &oob))
 666			return -EIO;
 667
 668	if (!sm_sector_valid(&oob) || !sm_block_valid(&oob))
 669		return -EIO;
 670
 671	if (!memcmp(ftl->cis_buffer + ftl->cis_page_offset,
 672			cis_signature, sizeof(cis_signature))) {
 673		return 0;
 674	}
 675
 676	return -EIO;
 677}
 678
 679/* Scan the media for the CIS */
 680static int sm_find_cis(struct sm_ftl *ftl)
 681{
 682	struct sm_oob oob;
 683	int block, boffset;
 684	int block_found = 0;
 685	int cis_found = 0;
 686
 687	/* Search for first valid block */
 688	for (block = 0 ; block < ftl->zone_size - ftl->max_lba ; block++) {
 689
 690		if (sm_read_sector(ftl, 0, block, 0, NULL, &oob))
 691			continue;
 692
 693		if (!sm_block_valid(&oob))
 694			continue;
 695		block_found = 1;
 696		break;
 697	}
 698
 699	if (!block_found)
 700		return -EIO;
 701
 702	/* Search for first valid sector in this block */
 703	for (boffset = 0 ; boffset < ftl->block_size;
 704						boffset += SM_SECTOR_SIZE) {
 705
 706		if (sm_read_sector(ftl, 0, block, boffset, NULL, &oob))
 707			continue;
 708
 709		if (!sm_sector_valid(&oob))
 710			continue;
 711		break;
 712	}
 713
 714	if (boffset == ftl->block_size)
 715		return -EIO;
 716
 717	ftl->cis_block = block;
 718	ftl->cis_boffset = boffset;
 719	ftl->cis_page_offset = 0;
 720
 721	cis_found = !sm_read_cis(ftl);
 722
 723	if (!cis_found) {
 724		ftl->cis_page_offset = SM_SMALL_PAGE;
 725		cis_found = !sm_read_cis(ftl);
 726	}
 727
 728	if (cis_found) {
 729		dbg("CIS block found at offset %x",
 730			block * ftl->block_size +
 731				boffset + ftl->cis_page_offset);
 732		return 0;
 733	}
 734	return -EIO;
 735}
 736
 737/* Basic test to determine if underlying mtd device if functional */
 738static int sm_recheck_media(struct sm_ftl *ftl)
 739{
 740	if (sm_read_cis(ftl)) {
 741
 742		if (!ftl->unstable) {
 743			sm_printk("media unstable, not allowing writes");
 744			ftl->unstable = 1;
 745		}
 746		return -EIO;
 747	}
 748	return 0;
 749}
 750
 751/* Initialize a FTL zone */
 752static int sm_init_zone(struct sm_ftl *ftl, int zone_num)
 753{
 754	struct ftl_zone *zone = &ftl->zones[zone_num];
 755	struct sm_oob oob;
 756	uint16_t block;
 757	int lba;
 758	int i = 0;
 759	int len;
 760
 761	dbg("initializing zone %d", zone_num);
 762
 763	/* Allocate memory for FTL table */
 764	zone->lba_to_phys_table = kmalloc_array(ftl->max_lba, 2, GFP_KERNEL);
 765
 766	if (!zone->lba_to_phys_table)
 767		return -ENOMEM;
 768	memset(zone->lba_to_phys_table, -1, ftl->max_lba * 2);
 769
 770
 771	/* Allocate memory for free sectors FIFO */
 772	if (kfifo_alloc(&zone->free_sectors, ftl->zone_size * 2, GFP_KERNEL)) {
 773		kfree(zone->lba_to_phys_table);
 774		return -ENOMEM;
 775	}
 776
 777	/* Now scan the zone */
 778	for (block = 0 ; block < ftl->zone_size ; block++) {
 779
 780		/* Skip blocks till the CIS (including) */
 781		if (zone_num == 0 && block <= ftl->cis_block)
 782			continue;
 783
 784		/* Read the oob of first sector */
 785		if (sm_read_sector(ftl, zone_num, block, 0, NULL, &oob)) {
 786			kfifo_free(&zone->free_sectors);
 787			kfree(zone->lba_to_phys_table);
 788			return -EIO;
 789		}
 790
 791		/* Test to see if block is erased. It is enough to test
 792		 * first sector, because erase happens in one shot
 793		 */
 794		if (sm_block_erased(&oob)) {
 795			kfifo_in(&zone->free_sectors,
 796				(unsigned char *)&block, 2);
 797			continue;
 798		}
 799
 800		/* If block is marked as bad, skip it */
 801		/* This assumes we can trust first sector*/
 802		/* However the way the block valid status is defined, ensures
 803		 * very low probability of failure here
 804		 */
 805		if (!sm_block_valid(&oob)) {
 806			dbg("PH %04d <-> <marked bad>", block);
 807			continue;
 808		}
 809
 810
 811		lba = sm_read_lba(&oob);
 812
 813		/* Invalid LBA means that block is damaged. */
 814		/* We can try to erase it, or mark it as bad, but
 815		 * lets leave that to recovery application
 816		 */
 817		if (lba == -2 || lba >= ftl->max_lba) {
 818			dbg("PH %04d <-> LBA %04d(bad)", block, lba);
 819			continue;
 820		}
 821
 822
 823		/* If there is no collision,
 824		 * just put the sector in the FTL table
 825		 */
 826		if (zone->lba_to_phys_table[lba] < 0) {
 827			dbg_verbose("PH %04d <-> LBA %04d", block, lba);
 828			zone->lba_to_phys_table[lba] = block;
 829			continue;
 830		}
 831
 832		sm_printk("collision"
 833			" of LBA %d between blocks %d and %d in zone %d",
 834			lba, zone->lba_to_phys_table[lba], block, zone_num);
 835
 836		/* Test that this block is valid*/
 837		if (sm_check_block(ftl, zone_num, block))
 838			continue;
 839
 840		/* Test now the old block */
 841		if (sm_check_block(ftl, zone_num,
 842					zone->lba_to_phys_table[lba])) {
 843			zone->lba_to_phys_table[lba] = block;
 844			continue;
 845		}
 846
 847		/* If both blocks are valid and share same LBA, it means that
 848		 * they hold different versions of same data. It not
 849		 * known which is more recent, thus just erase one of them
 850		 */
 851		sm_printk("both blocks are valid, erasing the later");
 852		sm_erase_block(ftl, zone_num, block, 1);
 853	}
 854
 855	dbg("zone initialized");
 856	zone->initialized = 1;
 857
 858	/* No free sectors, means that the zone is heavily damaged, write won't
 859	 * work, but it can still can be (partially) read
 860	 */
 861	if (!kfifo_len(&zone->free_sectors)) {
 862		sm_printk("no free blocks in zone %d", zone_num);
 863		return 0;
 864	}
 865
 866	/* Randomize first block we write to */
 867	get_random_bytes(&i, 2);
 868	i %= (kfifo_len(&zone->free_sectors) / 2);
 869
 870	while (i--) {
 871		len = kfifo_out(&zone->free_sectors,
 872					(unsigned char *)&block, 2);
 873		WARN_ON(len != 2);
 874		kfifo_in(&zone->free_sectors, (const unsigned char *)&block, 2);
 875	}
 876	return 0;
 877}
 878
 879/* Get and automatically initialize an FTL mapping for one zone */
 880static struct ftl_zone *sm_get_zone(struct sm_ftl *ftl, int zone_num)
 881{
 882	struct ftl_zone *zone;
 883	int error;
 884
 885	BUG_ON(zone_num >= ftl->zone_count);
 886	zone = &ftl->zones[zone_num];
 887
 888	if (!zone->initialized) {
 889		error = sm_init_zone(ftl, zone_num);
 890
 891		if (error)
 892			return ERR_PTR(error);
 893	}
 894	return zone;
 895}
 896
 897
 898/* ----------------- cache handling ------------------------------------------*/
 899
 900/* Initialize the one block cache */
 901static void sm_cache_init(struct sm_ftl *ftl)
 902{
 903	ftl->cache_data_invalid_bitmap = 0xFFFFFFFF;
 904	ftl->cache_clean = 1;
 905	ftl->cache_zone = -1;
 906	ftl->cache_block = -1;
 907	/*memset(ftl->cache_data, 0xAA, ftl->block_size);*/
 908}
 909
 910/* Put sector in one block cache */
 911static void sm_cache_put(struct sm_ftl *ftl, char *buffer, int boffset)
 912{
 913	memcpy(ftl->cache_data + boffset, buffer, SM_SECTOR_SIZE);
 914	clear_bit(boffset / SM_SECTOR_SIZE, &ftl->cache_data_invalid_bitmap);
 915	ftl->cache_clean = 0;
 916}
 917
 918/* Read a sector from the cache */
 919static int sm_cache_get(struct sm_ftl *ftl, char *buffer, int boffset)
 920{
 921	if (test_bit(boffset / SM_SECTOR_SIZE,
 922		&ftl->cache_data_invalid_bitmap))
 923			return -1;
 924
 925	memcpy(buffer, ftl->cache_data + boffset, SM_SECTOR_SIZE);
 926	return 0;
 927}
 928
 929/* Write the cache to hardware */
 930static int sm_cache_flush(struct sm_ftl *ftl)
 931{
 932	struct ftl_zone *zone;
 933
 934	int sector_num;
 935	uint16_t write_sector;
 936	int zone_num = ftl->cache_zone;
 937	int block_num;
 938
 939	if (ftl->cache_clean)
 940		return 0;
 941
 942	if (ftl->unstable)
 943		return -EIO;
 944
 945	BUG_ON(zone_num < 0);
 946	zone = &ftl->zones[zone_num];
 947	block_num = zone->lba_to_phys_table[ftl->cache_block];
 948
 949
 950	/* Try to read all unread areas of the cache block*/
 951	for_each_set_bit(sector_num, &ftl->cache_data_invalid_bitmap,
 952		ftl->block_size / SM_SECTOR_SIZE) {
 953
 954		if (!sm_read_sector(ftl,
 955			zone_num, block_num, sector_num * SM_SECTOR_SIZE,
 956			ftl->cache_data + sector_num * SM_SECTOR_SIZE, NULL))
 957				clear_bit(sector_num,
 958					&ftl->cache_data_invalid_bitmap);
 959	}
 960restart:
 961
 962	if (ftl->unstable)
 963		return -EIO;
 964
 965	/* If there are no spare blocks, */
 966	/* we could still continue by erasing/writing the current block,
 967	 * but for such worn out media it doesn't worth the trouble,
 968	 * and the dangers
 969	 */
 970	if (kfifo_out(&zone->free_sectors,
 971				(unsigned char *)&write_sector, 2) != 2) {
 972		dbg("no free sectors for write!");
 973		return -EIO;
 974	}
 975
 976
 977	if (sm_write_block(ftl, ftl->cache_data, zone_num, write_sector,
 978		ftl->cache_block, ftl->cache_data_invalid_bitmap))
 979			goto restart;
 980
 981	/* Update the FTL table */
 982	zone->lba_to_phys_table[ftl->cache_block] = write_sector;
 983
 984	/* Write successful, so erase and free the old block */
 985	if (block_num > 0)
 986		sm_erase_block(ftl, zone_num, block_num, 1);
 987
 988	sm_cache_init(ftl);
 989	return 0;
 990}
 991
 992
 993/* flush timer, runs a second after last write */
 994static void sm_cache_flush_timer(struct timer_list *t)
 995{
 996	struct sm_ftl *ftl = from_timer(ftl, t, timer);
 997	queue_work(cache_flush_workqueue, &ftl->flush_work);
 998}
 999
1000/* cache flush work, kicked by timer */
1001static void sm_cache_flush_work(struct work_struct *work)
1002{
1003	struct sm_ftl *ftl = container_of(work, struct sm_ftl, flush_work);
1004	mutex_lock(&ftl->mutex);
1005	sm_cache_flush(ftl);
1006	mutex_unlock(&ftl->mutex);
1007	return;
1008}
1009
1010/* ---------------- outside interface -------------------------------------- */
1011
1012/* outside interface: read a sector */
1013static int sm_read(struct mtd_blktrans_dev *dev,
1014		   unsigned long sect_no, char *buf)
1015{
1016	struct sm_ftl *ftl = dev->priv;
1017	struct ftl_zone *zone;
1018	int error = 0, in_cache = 0;
1019	int zone_num, block, boffset;
1020
1021	sm_break_offset(ftl, sect_no << 9, &zone_num, &block, &boffset);
1022	mutex_lock(&ftl->mutex);
1023
1024
1025	zone = sm_get_zone(ftl, zone_num);
1026	if (IS_ERR(zone)) {
1027		error = PTR_ERR(zone);
1028		goto unlock;
1029	}
1030
1031	/* Have to look at cache first */
1032	if (ftl->cache_zone == zone_num && ftl->cache_block == block) {
1033		in_cache = 1;
1034		if (!sm_cache_get(ftl, buf, boffset))
1035			goto unlock;
1036	}
1037
1038	/* Translate the block and return if doesn't exist in the table */
1039	block = zone->lba_to_phys_table[block];
1040
1041	if (block == -1) {
1042		memset(buf, 0xFF, SM_SECTOR_SIZE);
1043		goto unlock;
1044	}
1045
1046	if (sm_read_sector(ftl, zone_num, block, boffset, buf, NULL)) {
1047		error = -EIO;
1048		goto unlock;
1049	}
1050
1051	if (in_cache)
1052		sm_cache_put(ftl, buf, boffset);
1053unlock:
1054	mutex_unlock(&ftl->mutex);
1055	return error;
1056}
1057
1058/* outside interface: write a sector */
1059static int sm_write(struct mtd_blktrans_dev *dev,
1060				unsigned long sec_no, char *buf)
1061{
1062	struct sm_ftl *ftl = dev->priv;
1063	struct ftl_zone *zone;
1064	int error = 0, zone_num, block, boffset;
1065
1066	BUG_ON(ftl->readonly);
1067	sm_break_offset(ftl, sec_no << 9, &zone_num, &block, &boffset);
1068
1069	/* No need in flush thread running now */
1070	del_timer(&ftl->timer);
1071	mutex_lock(&ftl->mutex);
1072
1073	zone = sm_get_zone(ftl, zone_num);
1074	if (IS_ERR(zone)) {
1075		error = PTR_ERR(zone);
1076		goto unlock;
1077	}
1078
1079	/* If entry is not in cache, flush it */
1080	if (ftl->cache_block != block || ftl->cache_zone != zone_num) {
1081
1082		error = sm_cache_flush(ftl);
1083		if (error)
1084			goto unlock;
1085
1086		ftl->cache_block = block;
1087		ftl->cache_zone = zone_num;
1088	}
1089
1090	sm_cache_put(ftl, buf, boffset);
1091unlock:
1092	mod_timer(&ftl->timer, jiffies + msecs_to_jiffies(cache_timeout));
1093	mutex_unlock(&ftl->mutex);
1094	return error;
1095}
1096
1097/* outside interface: flush everything */
1098static int sm_flush(struct mtd_blktrans_dev *dev)
1099{
1100	struct sm_ftl *ftl = dev->priv;
1101	int retval;
1102
1103	mutex_lock(&ftl->mutex);
1104	retval =  sm_cache_flush(ftl);
1105	mutex_unlock(&ftl->mutex);
1106	return retval;
1107}
1108
1109/* outside interface: device is released */
1110static void sm_release(struct mtd_blktrans_dev *dev)
1111{
1112	struct sm_ftl *ftl = dev->priv;
1113
1114	del_timer_sync(&ftl->timer);
1115	cancel_work_sync(&ftl->flush_work);
1116	mutex_lock(&ftl->mutex);
1117	sm_cache_flush(ftl);
1118	mutex_unlock(&ftl->mutex);
1119}
1120
1121/* outside interface: get geometry */
1122static int sm_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
1123{
1124	struct sm_ftl *ftl = dev->priv;
1125	geo->heads = ftl->heads;
1126	geo->sectors = ftl->sectors;
1127	geo->cylinders = ftl->cylinders;
1128	return 0;
1129}
1130
1131/* external interface: main initialization function */
1132static void sm_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
1133{
1134	struct mtd_blktrans_dev *trans;
1135	struct sm_ftl *ftl;
1136
1137	/* Allocate & initialize our private structure */
1138	ftl = kzalloc(sizeof(struct sm_ftl), GFP_KERNEL);
1139	if (!ftl)
1140		goto error1;
1141
1142
1143	mutex_init(&ftl->mutex);
1144	timer_setup(&ftl->timer, sm_cache_flush_timer, 0);
1145	INIT_WORK(&ftl->flush_work, sm_cache_flush_work);
1146
1147	/* Read media information */
1148	if (sm_get_media_info(ftl, mtd)) {
1149		dbg("found unsupported mtd device, aborting");
1150		goto error2;
1151	}
1152
1153
1154	/* Allocate temporary CIS buffer for read retry support */
1155	ftl->cis_buffer = kzalloc(SM_SECTOR_SIZE, GFP_KERNEL);
1156	if (!ftl->cis_buffer)
1157		goto error2;
1158
1159	/* Allocate zone array, it will be initialized on demand */
1160	ftl->zones = kcalloc(ftl->zone_count, sizeof(struct ftl_zone),
1161								GFP_KERNEL);
1162	if (!ftl->zones)
1163		goto error3;
1164
1165	/* Allocate the cache*/
1166	ftl->cache_data = kzalloc(ftl->block_size, GFP_KERNEL);
1167
1168	if (!ftl->cache_data)
1169		goto error4;
1170
1171	sm_cache_init(ftl);
1172
1173
1174	/* Allocate upper layer structure and initialize it */
1175	trans = kzalloc(sizeof(struct mtd_blktrans_dev), GFP_KERNEL);
1176	if (!trans)
1177		goto error5;
1178
1179	ftl->trans = trans;
1180	trans->priv = ftl;
1181
1182	trans->tr = tr;
1183	trans->mtd = mtd;
1184	trans->devnum = -1;
1185	trans->size = (ftl->block_size * ftl->max_lba * ftl->zone_count) >> 9;
1186	trans->readonly = ftl->readonly;
1187
1188	if (sm_find_cis(ftl)) {
1189		dbg("CIS not found on mtd device, aborting");
1190		goto error6;
1191	}
1192
1193	ftl->disk_attributes = sm_create_sysfs_attributes(ftl);
1194	if (!ftl->disk_attributes)
1195		goto error6;
1196	trans->disk_attributes = ftl->disk_attributes;
1197
1198	sm_printk("Found %d MiB xD/SmartMedia FTL on mtd%d",
1199		(int)(mtd->size / (1024 * 1024)), mtd->index);
1200
1201	dbg("FTL layout:");
1202	dbg("%d zone(s), each consists of %d blocks (+%d spares)",
1203		ftl->zone_count, ftl->max_lba,
1204		ftl->zone_size - ftl->max_lba);
1205	dbg("each block consists of %d bytes",
1206		ftl->block_size);
1207
1208
1209	/* Register device*/
1210	if (add_mtd_blktrans_dev(trans)) {
1211		dbg("error in mtdblktrans layer");
1212		goto error6;
1213	}
1214	return;
1215error6:
1216	kfree(trans);
1217error5:
1218	kfree(ftl->cache_data);
1219error4:
1220	kfree(ftl->zones);
1221error3:
1222	kfree(ftl->cis_buffer);
1223error2:
1224	kfree(ftl);
1225error1:
1226	return;
1227}
1228
1229/* main interface: device {surprise,} removal */
1230static void sm_remove_dev(struct mtd_blktrans_dev *dev)
1231{
1232	struct sm_ftl *ftl = dev->priv;
1233	int i;
1234
1235	del_mtd_blktrans_dev(dev);
1236	ftl->trans = NULL;
1237
1238	for (i = 0 ; i < ftl->zone_count; i++) {
1239
1240		if (!ftl->zones[i].initialized)
1241			continue;
1242
1243		kfree(ftl->zones[i].lba_to_phys_table);
1244		kfifo_free(&ftl->zones[i].free_sectors);
1245	}
1246
1247	sm_delete_sysfs_attributes(ftl);
1248	kfree(ftl->cis_buffer);
1249	kfree(ftl->zones);
1250	kfree(ftl->cache_data);
1251	kfree(ftl);
1252}
1253
1254static struct mtd_blktrans_ops sm_ftl_ops = {
1255	.name		= "smblk",
1256	.major		= 0,
1257	.part_bits	= SM_FTL_PARTN_BITS,
1258	.blksize	= SM_SECTOR_SIZE,
1259	.getgeo		= sm_getgeo,
1260
1261	.add_mtd	= sm_add_mtd,
1262	.remove_dev	= sm_remove_dev,
1263
1264	.readsect	= sm_read,
1265	.writesect	= sm_write,
1266
1267	.flush		= sm_flush,
1268	.release	= sm_release,
1269
1270	.owner		= THIS_MODULE,
1271};
1272
1273static __init int sm_module_init(void)
1274{
1275	int error = 0;
1276
1277	cache_flush_workqueue = create_freezable_workqueue("smflush");
1278	if (!cache_flush_workqueue)
1279		return -ENOMEM;
1280
1281	error = register_mtd_blktrans(&sm_ftl_ops);
1282	if (error)
1283		destroy_workqueue(cache_flush_workqueue);
1284	return error;
1285
1286}
1287
1288static void __exit sm_module_exit(void)
1289{
1290	destroy_workqueue(cache_flush_workqueue);
1291	deregister_mtd_blktrans(&sm_ftl_ops);
1292}
1293
1294module_init(sm_module_init);
1295module_exit(sm_module_exit);
1296
1297MODULE_LICENSE("GPL");
1298MODULE_AUTHOR("Maxim Levitsky <maximlevitsky@gmail.com>");
1299MODULE_DESCRIPTION("Smartmedia/xD mtd translation layer");