[deliverable/linux.git] / drivers / mtd / ssfdc.c

/*
 * Linux driver for SSFDC Flash Translation Layer (Read only)
 * © 2005 Eptar srl
 * Author: Claudio Lanconelli <lanconelli.claudio@eptar.com>
 *
 * Based on NTFL and MTDBLOCK_RO drivers
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/hdreg.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/blktrans.h>

struct ssfdcr_record {
	struct mtd_blktrans_dev mbd;
	int usecount;
	unsigned char heads;
	unsigned char sectors;
	unsigned short cylinders;
	int cis_block;			/* block n. containing CIS/IDI */
	int erase_size;			/* phys_block_size */
	unsigned short *logic_block_map; /* all zones (max 8192 phys blocks on
					    the 128MiB) */
	int map_len;			/* n. phys_blocks on the card */
};

#define SSFDCR_MAJOR		257
#define SSFDCR_PARTN_BITS	3

#define SECTOR_SIZE		512
#define SECTOR_SHIFT		9
#define OOB_SIZE		16

#define MAX_LOGIC_BLK_PER_ZONE	1000
#define MAX_PHYS_BLK_PER_ZONE	1024

#define KiB(x)	( (x) * 1024L )
#define MiB(x)	( KiB(x) * 1024L )

/** CHS Table
		1MiB	2MiB	4MiB	8MiB	16MiB	32MiB	64MiB	128MiB
NCylinder	125	125	250	250	500	500	500	500
NHead		4	4	4	4	4	8	8	16
NSector		4	8	8	16	16	16	32	32
SumSector	2,000	4,000	8,000	16,000	32,000	64,000	128,000	256,000
SectorSize	512	512	512	512	512	512	512	512
**/

typedef struct {
	unsigned long size;
	unsigned short cyl;
	unsigned char head;
	unsigned char sec;
} chs_entry_t;

/* Must be ordered by size */
static const chs_entry_t chs_table[] = {
	{ MiB(  1), 125,  4,  4 },
	{ MiB(  2), 125,  4,  8 },
	{ MiB(  4), 250,  4,  8 },
	{ MiB(  8), 250,  4, 16 },
	{ MiB( 16), 500,  4, 16 },
	{ MiB( 32), 500,  8, 16 },
	{ MiB( 64), 500,  8, 32 },
	{ MiB(128), 500, 16, 32 },
	{ 0 },
};

static int get_chs(unsigned long size, unsigned short *cyl, unsigned char *head,
			unsigned char *sec)
{
	int k;
	int found = 0;

	k = 0;
	while (chs_table[k].size > 0 && size > chs_table[k].size)
		k++;

	if (chs_table[k].size > 0) {
		if (cyl)
			*cyl = chs_table[k].cyl;
		if (head)
			*head = chs_table[k].head;
		if (sec)
			*sec = chs_table[k].sec;
		found = 1;
	}

	return found;
}

/* These bytes are the signature for the CIS/IDI sector */
static const uint8_t cis_numbers[] = {
	0x01, 0x03, 0xD9, 0x01, 0xFF, 0x18, 0x02, 0xDF, 0x01, 0x20
};

/* Read and check for a valid CIS sector */
static int get_valid_cis_sector(struct mtd_info *mtd)
{
	int ret, k, cis_sector;
	size_t retlen;
	loff_t offset;
	uint8_t *sect_buf;

	cis_sector = -1;

	sect_buf = kmalloc(SECTOR_SIZE, GFP_KERNEL);
	if (!sect_buf)
		goto out;

	/*
	 * Look for CIS/IDI sector on the first GOOD block (give up after 4 bad
	 * blocks). If the first good block doesn't contain CIS number the flash
	 * is not SSFDC formatted
	 */
	for (k = 0, offset = 0; k < 4; k++, offset += mtd->erasesize) {
		if (mtd_block_isbad(mtd, offset)) {
			ret = mtd_read(mtd, offset, SECTOR_SIZE, &retlen,
				       sect_buf);

			/* CIS pattern match on the sector buffer */
			if (ret < 0 || retlen != SECTOR_SIZE) {
				printk(KERN_WARNING
					"SSFDC_RO:can't read CIS/IDI sector\n");
			} else if (!memcmp(sect_buf, cis_numbers,
					sizeof(cis_numbers))) {
				/* Found */
				cis_sector = (int)(offset >> SECTOR_SHIFT);
			} else {
				pr_debug("SSFDC_RO: CIS/IDI sector not found"
					" on %s (mtd%d)\n", mtd->name,
					mtd->index);
			}
			break;
		}
	}

	kfree(sect_buf);
 out:
	return cis_sector;
}

/* Read physical sector (wrapper to MTD_READ) */
static int read_physical_sector(struct mtd_info *mtd, uint8_t *sect_buf,
				int sect_no)
{
	int ret;
	size_t retlen;
	loff_t offset = (loff_t)sect_no << SECTOR_SHIFT;

	ret = mtd_read(mtd, offset, SECTOR_SIZE, &retlen, sect_buf);
	if (ret < 0 || retlen != SECTOR_SIZE)
		return -1;

	return 0;
}

/* Read redundancy area (wrapper to MTD_READ_OOB */
static int read_raw_oob(struct mtd_info *mtd, loff_t offs, uint8_t *buf)
{
	struct mtd_oob_ops ops;
	int ret;

	ops.mode = MTD_OPS_RAW;
	ops.ooboffs = 0;
	ops.ooblen = OOB_SIZE;
	ops.oobbuf = buf;
	ops.datbuf = NULL;

	ret = mtd_read_oob(mtd, offs, &ops);
	if (ret < 0 || ops.oobretlen != OOB_SIZE)
		return -1;

	return 0;
}

/* Parity calculator on a word of n bit size */
static int get_parity(int number, int size)
{
 	int k;
	int parity;

	parity = 1;
	for (k = 0; k < size; k++) {
		parity += (number >> k);
		parity &= 1;
	}
	return parity;
}

/* Read and validate the logical block address field stored in the OOB */
static int get_logical_address(uint8_t *oob_buf)
{
	int block_address, parity;
	int offset[2] = {6, 11}; /* offset of the 2 address fields within OOB */
	int j;
	int ok = 0;

	/*
	 * Look for the first valid logical address
	 * Valid address has fixed pattern on most significant bits and
	 * parity check
	 */
	for (j = 0; j < ARRAY_SIZE(offset); j++) {
		block_address = ((int)oob_buf[offset[j]] << 8) |
			oob_buf[offset[j]+1];

		/* Check for the signature bits in the address field (MSBits) */
		if ((block_address & ~0x7FF) == 0x1000) {
			parity = block_address & 0x01;
			block_address &= 0x7FF;
			block_address >>= 1;

			if (get_parity(block_address, 10) != parity) {
				pr_debug("SSFDC_RO: logical address field%d"
					"parity error(0x%04X)\n", j+1,
					block_address);
			} else {
				ok = 1;
				break;
			}
		}
	}

	if (!ok)
		block_address = -2;

	pr_debug("SSFDC_RO: get_logical_address() %d\n",
		block_address);

	return block_address;
}

/* Build the logic block map */
static int build_logical_block_map(struct ssfdcr_record *ssfdc)
{
	unsigned long offset;
	uint8_t oob_buf[OOB_SIZE];
	int ret, block_address, phys_block;
	struct mtd_info *mtd = ssfdc->mbd.mtd;

	pr_debug("SSFDC_RO: build_block_map() nblks=%d (%luK)\n",
	      ssfdc->map_len,
	      (unsigned long)ssfdc->map_len * ssfdc->erase_size / 1024);

	/* Scan every physical block, skip CIS block */
	for (phys_block = ssfdc->cis_block + 1; phys_block < ssfdc->map_len;
			phys_block++) {
		offset = (unsigned long)phys_block * ssfdc->erase_size;
		if (mtd_block_isbad(mtd, offset))
			continue;	/* skip bad blocks */

		ret = read_raw_oob(mtd, offset, oob_buf);
		if (ret < 0) {
			pr_debug("SSFDC_RO: mtd read_oob() failed at %lu\n",
				offset);
			return -1;
		}
		block_address = get_logical_address(oob_buf);

		/* Skip invalid addresses */
		if (block_address >= 0 &&
				block_address < MAX_LOGIC_BLK_PER_ZONE) {
			int zone_index;

			zone_index = phys_block / MAX_PHYS_BLK_PER_ZONE;
			block_address += zone_index * MAX_LOGIC_BLK_PER_ZONE;
			ssfdc->logic_block_map[block_address] =
				(unsigned short)phys_block;

			pr_debug("SSFDC_RO: build_block_map() phys_block=%d,"
				"logic_block_addr=%d, zone=%d\n",
				phys_block, block_address, zone_index);
		}
	}
	return 0;
}

static void ssfdcr_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
{
	struct ssfdcr_record *ssfdc;
	int cis_sector;

	/* Check for small page NAND flash */
	if (!mtd_type_is_nand(mtd) || mtd->oobsize != OOB_SIZE ||
	    mtd->size > UINT_MAX)
		return;

	/* Check for SSDFC format by reading CIS/IDI sector */
	cis_sector = get_valid_cis_sector(mtd);
	if (cis_sector == -1)
		return;

	ssfdc = kzalloc(sizeof(struct ssfdcr_record), GFP_KERNEL);
	if (!ssfdc)
		return;

	ssfdc->mbd.mtd = mtd;
	ssfdc->mbd.devnum = -1;
	ssfdc->mbd.tr = tr;
	ssfdc->mbd.readonly = 1;

	ssfdc->cis_block = cis_sector / (mtd->erasesize >> SECTOR_SHIFT);
	ssfdc->erase_size = mtd->erasesize;
	ssfdc->map_len = (u32)mtd->size / mtd->erasesize;

	pr_debug("SSFDC_RO: cis_block=%d,erase_size=%d,map_len=%d,n_zones=%d\n",
		ssfdc->cis_block, ssfdc->erase_size, ssfdc->map_len,
		DIV_ROUND_UP(ssfdc->map_len, MAX_PHYS_BLK_PER_ZONE));

	/* Set geometry */
	ssfdc->heads = 16;
	ssfdc->sectors = 32;
	get_chs(mtd->size, NULL, &ssfdc->heads, &ssfdc->sectors);
	ssfdc->cylinders = (unsigned short)(((u32)mtd->size >> SECTOR_SHIFT) /
			((long)ssfdc->sectors * (long)ssfdc->heads));

	pr_debug("SSFDC_RO: using C:%d H:%d S:%d == %ld sects\n",
		ssfdc->cylinders, ssfdc->heads , ssfdc->sectors,
		(long)ssfdc->cylinders * (long)ssfdc->heads *
		(long)ssfdc->sectors);

	ssfdc->mbd.size = (long)ssfdc->heads * (long)ssfdc->cylinders *
				(long)ssfdc->sectors;

	/* Allocate logical block map */
	ssfdc->logic_block_map = kmalloc(sizeof(ssfdc->logic_block_map[0]) *
					 ssfdc->map_len, GFP_KERNEL);
	if (!ssfdc->logic_block_map)
		goto out_err;
	memset(ssfdc->logic_block_map, 0xff, sizeof(ssfdc->logic_block_map[0]) *
		ssfdc->map_len);

	/* Build logical block map */
	if (build_logical_block_map(ssfdc) < 0)
		goto out_err;

	/* Register device + partitions */
	if (add_mtd_blktrans_dev(&ssfdc->mbd))
		goto out_err;

	printk(KERN_INFO "SSFDC_RO: Found ssfdc%c on mtd%d (%s)\n",
		ssfdc->mbd.devnum + 'a', mtd->index, mtd->name);
	return;

out_err:
	kfree(ssfdc->logic_block_map);
        kfree(ssfdc);
}

static void ssfdcr_remove_dev(struct mtd_blktrans_dev *dev)
{
	struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev;

	pr_debug("SSFDC_RO: remove_dev (i=%d)\n", dev->devnum);

	del_mtd_blktrans_dev(dev);
	kfree(ssfdc->logic_block_map);
}

static int ssfdcr_readsect(struct mtd_blktrans_dev *dev,
				unsigned long logic_sect_no, char *buf)
{
	struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev;
	int sectors_per_block, offset, block_address;

	sectors_per_block = ssfdc->erase_size >> SECTOR_SHIFT;
	offset = (int)(logic_sect_no % sectors_per_block);
	block_address = (int)(logic_sect_no / sectors_per_block);

	pr_debug("SSFDC_RO: ssfdcr_readsect(%lu) sec_per_blk=%d, ofst=%d,"
		" block_addr=%d\n", logic_sect_no, sectors_per_block, offset,
		block_address);

	if (block_address >= ssfdc->map_len)
		BUG();

	block_address = ssfdc->logic_block_map[block_address];

	pr_debug("SSFDC_RO: ssfdcr_readsect() phys_block_addr=%d\n",
		block_address);

	if (block_address < 0xffff) {
		unsigned long sect_no;

		sect_no = (unsigned long)block_address * sectors_per_block +
				offset;

		pr_debug("SSFDC_RO: ssfdcr_readsect() phys_sect_no=%lu\n",
			sect_no);

		if (read_physical_sector(ssfdc->mbd.mtd, buf, sect_no) < 0)
			return -EIO;
	} else {
		memset(buf, 0xff, SECTOR_SIZE);
	}

	return 0;
}

static int ssfdcr_getgeo(struct mtd_blktrans_dev *dev,  struct hd_geometry *geo)
{
	struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev;

	pr_debug("SSFDC_RO: ssfdcr_getgeo() C=%d, H=%d, S=%d\n",
			ssfdc->cylinders, ssfdc->heads, ssfdc->sectors);

	geo->heads = ssfdc->heads;
	geo->sectors = ssfdc->sectors;
	geo->cylinders = ssfdc->cylinders;

	return 0;
}

/****************************************************************************
 *
 * Module stuff
 *
 ****************************************************************************/

static struct mtd_blktrans_ops ssfdcr_tr = {
	.name		= "ssfdc",
	.major		= SSFDCR_MAJOR,
	.part_bits	= SSFDCR_PARTN_BITS,
	.blksize	= SECTOR_SIZE,
	.getgeo		= ssfdcr_getgeo,
	.readsect	= ssfdcr_readsect,
	.add_mtd	= ssfdcr_add_mtd,
	.remove_dev	= ssfdcr_remove_dev,
	.owner		= THIS_MODULE,
};

static int __init init_ssfdcr(void)
{
	printk(KERN_INFO "SSFDC read-only Flash Translation layer\n");

	return register_mtd_blktrans(&ssfdcr_tr);
}

static void __exit cleanup_ssfdcr(void)
{
	deregister_mtd_blktrans(&ssfdcr_tr);
}

module_init(init_ssfdcr);
module_exit(cleanup_ssfdcr);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Claudio Lanconelli <lanconelli.claudio@eptar.com>");
MODULE_DESCRIPTION("Flash Translation Layer for read-only SSFDC SmartMedia card");
Commit	Line	Data
51197abf CL	1	/*
51197abf CL	2	* Linux driver for SSFDC Flash Translation Layer (Read only)
a1452a37	3	* © 2005 Eptar srl
51197abf CL	4	* Author: Claudio Lanconelli <lanconelli.claudio@eptar.com>
	5	*
	6	* Based on NTFL and MTDBLOCK_RO drivers
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*/
	12
51197abf CL	13	#include <linux/kernel.h>
	14	#include <linux/module.h>
	15	#include <linux/init.h>
	16	#include <linux/slab.h>
	17	#include <linux/hdreg.h>
	18	#include <linux/mtd/mtd.h>
	19	#include <linux/mtd/nand.h>
	20	#include <linux/mtd/blktrans.h>
	21
	22	struct ssfdcr_record {
	23	struct mtd_blktrans_dev mbd;
	24	int usecount;
	25	unsigned char heads;
	26	unsigned char sectors;
	27	unsigned short cylinders;
	28	int cis_block; /* block n. containing CIS/IDI */
	29	int erase_size; /* phys_block_size */
	30	unsigned short logic_block_map; / all zones (max 8192 phys blocks on
9a05eded	31	the 128MiB) */
51197abf CL	32	int map_len; /* n. phys_blocks on the card */
	33	};
	34
	35	#define SSFDCR_MAJOR 257
	36	#define SSFDCR_PARTN_BITS 3
	37
	38	#define SECTOR_SIZE 512
	39	#define SECTOR_SHIFT 9
	40	#define OOB_SIZE 16
	41
	42	#define MAX_LOGIC_BLK_PER_ZONE 1000
	43	#define MAX_PHYS_BLK_PER_ZONE 1024
	44
9a05eded DW	45	#define KiB(x) ( (x) * 1024L )
9a05eded DW	46	#define MiB(x) ( KiB(x) * 1024L )
51197abf CL	47
51197abf CL	48	/** CHS Table
9a05eded	49	1MiB 2MiB 4MiB 8MiB 16MiB 32MiB 64MiB 128MiB
51197abf CL	50	NCylinder 125 125 250 250 500 500 500 500
	51	NHead 4 4 4 4 4 8 8 16
	52	NSector 4 8 8 16 16 16 32 32
	53	SumSector 2,000 4,000 8,000 16,000 32,000 64,000 128,000 256,000
	54	SectorSize 512 512 512 512 512 512 512 512
	55	**/
	56
	57	typedef struct {
	58	unsigned long size;
	59	unsigned short cyl;
	60	unsigned char head;
	61	unsigned char sec;
	62	} chs_entry_t;
	63
	64	/* Must be ordered by size */
	65	static const chs_entry_t chs_table[] = {
9a05eded DW	66	{ MiB( 1), 125, 4, 4 },
	67	{ MiB( 2), 125, 4, 8 },
	68	{ MiB( 4), 250, 4, 8 },
	69	{ MiB( 8), 250, 4, 16 },
	70	{ MiB( 16), 500, 4, 16 },
	71	{ MiB( 32), 500, 8, 16 },
	72	{ MiB( 64), 500, 8, 32 },
	73	{ MiB(128), 500, 16, 32 },
51197abf CL	74	{ 0 },
	75	};
	76
	77	static int get_chs(unsigned long size, unsigned short cyl, unsigned char head,
	78	unsigned char *sec)
	79	{
	80	int k;
	81	int found = 0;
	82
	83	k = 0;
	84	while (chs_table[k].size > 0 && size > chs_table[k].size)
	85	k++;
	86
	87	if (chs_table[k].size > 0) {
	88	if (cyl)
	89	*cyl = chs_table[k].cyl;
	90	if (head)
	91	*head = chs_table[k].head;
	92	if (sec)
	93	*sec = chs_table[k].sec;
	94	found = 1;
	95	}
	96
	97	return found;
	98	}
	99
	100	/* These bytes are the signature for the CIS/IDI sector */
	101	static const uint8_t cis_numbers[] = {
	102	0x01, 0x03, 0xD9, 0x01, 0xFF, 0x18, 0x02, 0xDF, 0x01, 0x20
	103	};
	104
	105	/* Read and check for a valid CIS sector */
	106	static int get_valid_cis_sector(struct mtd_info *mtd)
	107	{
	108	int ret, k, cis_sector;
	109	size_t retlen;
	110	loff_t offset;
9a05eded DW	111	uint8_t *sect_buf;
	112
	113	cis_sector = -1;
	114
	115	sect_buf = kmalloc(SECTOR_SIZE, GFP_KERNEL);
	116	if (!sect_buf)
	117	goto out;
51197abf CL	118
	119	/*
	120	* Look for CIS/IDI sector on the first GOOD block (give up after 4 bad
	121	* blocks). If the first good block doesn't contain CIS number the flash
	122	* is not SSFDC formatted
	123	*/
51197abf	124	for (k = 0, offset = 0; k < 4; k++, offset += mtd->erasesize) {
7086c19d	125	if (mtd_block_isbad(mtd, offset)) {
329ad399 AB	126	ret = mtd_read(mtd, offset, SECTOR_SIZE, &retlen,
329ad399 AB	127	sect_buf);
51197abf CL	128
51197abf CL	129	/* CIS pattern match on the sector buffer */
08d3ad6a	130	if (ret < 0 \|\| retlen != SECTOR_SIZE) {
51197abf CL	131	printk(KERN_WARNING
51197abf CL	132	"SSFDC_RO:can't read CIS/IDI sector\n");
08d3ad6a DW	133	} else if (!memcmp(sect_buf, cis_numbers,
08d3ad6a DW	134	sizeof(cis_numbers))) {
51197abf CL	135	/* Found */
	136	cis_sector = (int)(offset >> SECTOR_SHIFT);
	137	} else {
289c0522	138	pr_debug("SSFDC_RO: CIS/IDI sector not found"
51197abf CL	139	" on %s (mtd%d)\n", mtd->name,
	140	mtd->index);
	141	}
	142	break;
	143	}
	144	}
	145
9a05eded DW	146	kfree(sect_buf);
9a05eded DW	147	out:
51197abf CL	148	return cis_sector;
	149	}
	150
	151	/* Read physical sector (wrapper to MTD_READ) */
	152	static int read_physical_sector(struct mtd_info mtd, uint8_t sect_buf,
	153	int sect_no)
	154	{
	155	int ret;
	156	size_t retlen;
	157	loff_t offset = (loff_t)sect_no << SECTOR_SHIFT;
	158
329ad399	159	ret = mtd_read(mtd, offset, SECTOR_SIZE, &retlen, sect_buf);
51197abf CL	160	if (ret < 0 \|\| retlen != SECTOR_SIZE)
	161	return -1;
	162
	163	return 0;
	164	}
	165
	166	/* Read redundancy area (wrapper to MTD_READ_OOB */
	167	static int read_raw_oob(struct mtd_info mtd, loff_t offs, uint8_t buf)
	168	{
	169	struct mtd_oob_ops ops;
	170	int ret;
	171
0612b9dd	172	ops.mode = MTD_OPS_RAW;
51197abf	173	ops.ooboffs = 0;
7014568b	174	ops.ooblen = OOB_SIZE;
51197abf CL	175	ops.oobbuf = buf;
	176	ops.datbuf = NULL;
	177
fd2819bb	178	ret = mtd_read_oob(mtd, offs, &ops);
7014568b	179	if (ret < 0 \|\| ops.oobretlen != OOB_SIZE)
51197abf CL	180	return -1;
	181
	182	return 0;
	183	}
	184
	185	/* Parity calculator on a word of n bit size */
	186	static int get_parity(int number, int size)
	187	{
	188	int k;
	189	int parity;
	190
	191	parity = 1;
	192	for (k = 0; k < size; k++) {
	193	parity += (number >> k);
	194	parity &= 1;
	195	}
	196	return parity;
	197	}
	198
	199	/* Read and validate the logical block address field stored in the OOB */
	200	static int get_logical_address(uint8_t *oob_buf)
	201	{
	202	int block_address, parity;
	203	int offset[2] = {6, 11}; /* offset of the 2 address fields within OOB */
	204	int j;
	205	int ok = 0;
	206
	207	/*
	208	* Look for the first valid logical address
	209	* Valid address has fixed pattern on most significant bits and
	210	* parity check
	211	*/
	212	for (j = 0; j < ARRAY_SIZE(offset); j++) {
	213	block_address = ((int)oob_buf[offset[j]] << 8) \|
	214	oob_buf[offset[j]+1];
	215
	216	/* Check for the signature bits in the address field (MSBits) */
	217	if ((block_address & ~0x7FF) == 0x1000) {
	218	parity = block_address & 0x01;
	219	block_address &= 0x7FF;
	220	block_address >>= 1;
	221
	222	if (get_parity(block_address, 10) != parity) {
289c0522	223	pr_debug("SSFDC_RO: logical address field%d"
51197abf CL	224	"parity error(0x%04X)\n", j+1,
	225	block_address);
	226	} else {
	227	ok = 1;
	228	break;
	229	}
	230	}
	231	}
	232
08d3ad6a	233	if (!ok)
51197abf CL	234	block_address = -2;
51197abf CL	235
289c0522	236	pr_debug("SSFDC_RO: get_logical_address() %d\n",
51197abf CL	237	block_address);
	238
	239	return block_address;
	240	}
	241
	242	/* Build the logic block map */
	243	static int build_logical_block_map(struct ssfdcr_record *ssfdc)
	244	{
	245	unsigned long offset;
	246	uint8_t oob_buf[OOB_SIZE];
	247	int ret, block_address, phys_block;
	248	struct mtd_info *mtd = ssfdc->mbd.mtd;
	249
289c0522	250	pr_debug("SSFDC_RO: build_block_map() nblks=%d (%luK)\n",
08d3ad6a DW	251	ssfdc->map_len,
08d3ad6a DW	252	(unsigned long)ssfdc->map_len * ssfdc->erase_size / 1024);
51197abf CL	253
	254	/* Scan every physical block, skip CIS block */
	255	for (phys_block = ssfdc->cis_block + 1; phys_block < ssfdc->map_len;
	256	phys_block++) {
	257	offset = (unsigned long)phys_block * ssfdc->erase_size;
7086c19d	258	if (mtd_block_isbad(mtd, offset))
51197abf CL	259	continue; /* skip bad blocks */
	260
	261	ret = read_raw_oob(mtd, offset, oob_buf);
	262	if (ret < 0) {
289c0522	263	pr_debug("SSFDC_RO: mtd read_oob() failed at %lu\n",
51197abf CL	264	offset);
	265	return -1;
	266	}
	267	block_address = get_logical_address(oob_buf);
	268
	269	/* Skip invalid addresses */
	270	if (block_address >= 0 &&
	271	block_address < MAX_LOGIC_BLK_PER_ZONE) {
	272	int zone_index;
	273
	274	zone_index = phys_block / MAX_PHYS_BLK_PER_ZONE;
	275	block_address += zone_index * MAX_LOGIC_BLK_PER_ZONE;
	276	ssfdc->logic_block_map[block_address] =
	277	(unsigned short)phys_block;
	278
289c0522	279	pr_debug("SSFDC_RO: build_block_map() phys_block=%d,"
51197abf CL	280	"logic_block_addr=%d, zone=%d\n",
	281	phys_block, block_address, zone_index);
	282	}
	283	}
	284	return 0;
	285	}
	286
	287	static void ssfdcr_add_mtd(struct mtd_blktrans_ops tr, struct mtd_info mtd)
	288	{
	289	struct ssfdcr_record *ssfdc;
	290	int cis_sector;
	291
	292	/* Check for small page NAND flash */
818b9739	293	if (!mtd_type_is_nand(mtd) \|\| mtd->oobsize != OOB_SIZE \|\|
69423d99	294	mtd->size > UINT_MAX)
51197abf CL	295	return;
	296
	297	/* Check for SSDFC format by reading CIS/IDI sector */
	298	cis_sector = get_valid_cis_sector(mtd);
	299	if (cis_sector == -1)
	300	return;
	301
	302	ssfdc = kzalloc(sizeof(struct ssfdcr_record), GFP_KERNEL);
0870066d	303	if (!ssfdc)
51197abf	304	return;
51197abf CL	305
	306	ssfdc->mbd.mtd = mtd;
	307	ssfdc->mbd.devnum = -1;
51197abf CL	308	ssfdc->mbd.tr = tr;
	309	ssfdc->mbd.readonly = 1;
	310
	311	ssfdc->cis_block = cis_sector / (mtd->erasesize >> SECTOR_SHIFT);
	312	ssfdc->erase_size = mtd->erasesize;
69423d99	313	ssfdc->map_len = (u32)mtd->size / mtd->erasesize;
51197abf	314
289c0522	315	pr_debug("SSFDC_RO: cis_block=%d,erase_size=%d,map_len=%d,n_zones=%d\n",
51197abf	316	ssfdc->cis_block, ssfdc->erase_size, ssfdc->map_len,
c8872b06	317	DIV_ROUND_UP(ssfdc->map_len, MAX_PHYS_BLK_PER_ZONE));
51197abf CL	318
	319	/* Set geometry */
	320	ssfdc->heads = 16;
	321	ssfdc->sectors = 32;
08d3ad6a	322	get_chs(mtd->size, NULL, &ssfdc->heads, &ssfdc->sectors);
69423d99	323	ssfdc->cylinders = (unsigned short)(((u32)mtd->size >> SECTOR_SHIFT) /
51197abf CL	324	((long)ssfdc->sectors * (long)ssfdc->heads));
51197abf CL	325
289c0522	326	pr_debug("SSFDC_RO: using C:%d H:%d S:%d == %ld sects\n",
51197abf CL	327	ssfdc->cylinders, ssfdc->heads , ssfdc->sectors,
51197abf CL	328	(long)ssfdc->cylinders * (long)ssfdc->heads *
08d3ad6a	329	(long)ssfdc->sectors);
51197abf CL	330
	331	ssfdc->mbd.size = (long)ssfdc->heads * (long)ssfdc->cylinders *
	332	(long)ssfdc->sectors;
	333
	334	/* Allocate logical block map */
08d3ad6a DW	335	ssfdc->logic_block_map = kmalloc(sizeof(ssfdc->logic_block_map[0]) *
08d3ad6a DW	336	ssfdc->map_len, GFP_KERNEL);
0870066d	337	if (!ssfdc->logic_block_map)
51197abf	338	goto out_err;
51197abf CL	339	memset(ssfdc->logic_block_map, 0xff, sizeof(ssfdc->logic_block_map[0]) *
	340	ssfdc->map_len);
	341
	342	/* Build logical block map */
	343	if (build_logical_block_map(ssfdc) < 0)
	344	goto out_err;
	345
	346	/* Register device + partitions */
	347	if (add_mtd_blktrans_dev(&ssfdc->mbd))
	348	goto out_err;
	349
	350	printk(KERN_INFO "SSFDC_RO: Found ssfdc%c on mtd%d (%s)\n",
	351	ssfdc->mbd.devnum + 'a', mtd->index, mtd->name);
	352	return;
	353
	354	out_err:
	355	kfree(ssfdc->logic_block_map);
	356	kfree(ssfdc);
	357	}
	358
	359	static void ssfdcr_remove_dev(struct mtd_blktrans_dev *dev)
	360	{
	361	struct ssfdcr_record ssfdc = (struct ssfdcr_record )dev;
	362
289c0522	363	pr_debug("SSFDC_RO: remove_dev (i=%d)\n", dev->devnum);
51197abf CL	364
	365	del_mtd_blktrans_dev(dev);
	366	kfree(ssfdc->logic_block_map);
51197abf CL	367	}
	368
	369	static int ssfdcr_readsect(struct mtd_blktrans_dev *dev,
	370	unsigned long logic_sect_no, char *buf)
	371	{
	372	struct ssfdcr_record ssfdc = (struct ssfdcr_record )dev;
	373	int sectors_per_block, offset, block_address;
	374
	375	sectors_per_block = ssfdc->erase_size >> SECTOR_SHIFT;
	376	offset = (int)(logic_sect_no % sectors_per_block);
	377	block_address = (int)(logic_sect_no / sectors_per_block);
	378
289c0522	379	pr_debug("SSFDC_RO: ssfdcr_readsect(%lu) sec_per_blk=%d, ofst=%d,"
51197abf CL	380	" block_addr=%d\n", logic_sect_no, sectors_per_block, offset,
	381	block_address);
	382
	383	if (block_address >= ssfdc->map_len)
	384	BUG();
	385
	386	block_address = ssfdc->logic_block_map[block_address];
	387
289c0522	388	pr_debug("SSFDC_RO: ssfdcr_readsect() phys_block_addr=%d\n",
51197abf CL	389	block_address);
	390
	391	if (block_address < 0xffff) {
	392	unsigned long sect_no;
	393
	394	sect_no = (unsigned long)block_address * sectors_per_block +
	395	offset;
	396
289c0522	397	pr_debug("SSFDC_RO: ssfdcr_readsect() phys_sect_no=%lu\n",
51197abf CL	398	sect_no);
51197abf CL	399
08d3ad6a	400	if (read_physical_sector(ssfdc->mbd.mtd, buf, sect_no) < 0)
51197abf CL	401	return -EIO;
	402	} else {
	403	memset(buf, 0xff, SECTOR_SIZE);
	404	}
	405
	406	return 0;
	407	}
	408
	409	static int ssfdcr_getgeo(struct mtd_blktrans_dev dev, struct hd_geometry geo)
	410	{
	411	struct ssfdcr_record ssfdc = (struct ssfdcr_record )dev;
	412
289c0522	413	pr_debug("SSFDC_RO: ssfdcr_getgeo() C=%d, H=%d, S=%d\n",
51197abf CL	414	ssfdc->cylinders, ssfdc->heads, ssfdc->sectors);
	415
	416	geo->heads = ssfdc->heads;
	417	geo->sectors = ssfdc->sectors;
	418	geo->cylinders = ssfdc->cylinders;
	419
	420	return 0;
	421	}
	422
	423	/****************************************************************************
	424	*
	425	* Module stuff
	426	*
	427	****************************************************************************/
	428
	429	static struct mtd_blktrans_ops ssfdcr_tr = {
	430	.name = "ssfdc",
	431	.major = SSFDCR_MAJOR,
	432	.part_bits = SSFDCR_PARTN_BITS,
76ab40e4	433	.blksize = SECTOR_SIZE,
51197abf CL	434	.getgeo = ssfdcr_getgeo,
	435	.readsect = ssfdcr_readsect,
	436	.add_mtd = ssfdcr_add_mtd,
	437	.remove_dev = ssfdcr_remove_dev,
	438	.owner = THIS_MODULE,
	439	};
	440
	441	static int __init init_ssfdcr(void)
	442	{
	443	printk(KERN_INFO "SSFDC read-only Flash Translation layer\n");
	444
	445	return register_mtd_blktrans(&ssfdcr_tr);
	446	}
	447
	448	static void __exit cleanup_ssfdcr(void)
	449	{
	450	deregister_mtd_blktrans(&ssfdcr_tr);
	451	}
	452
	453	module_init(init_ssfdcr);
	454	module_exit(cleanup_ssfdcr);
	455
	456	MODULE_LICENSE("GPL");
	457	MODULE_AUTHOR("Claudio Lanconelli <lanconelli.claudio@eptar.com>");
	458	MODULE_DESCRIPTION("Flash Translation Layer for read-only SSFDC SmartMedia card");