- 根目录:
- 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");