linux/drivers/mtd/onenand/onenand_bbt.c
Rohit Hagargundgi 5988af2319 mtd: Flex-OneNAND support
Add support for Samsung Flex-OneNAND devices.

Flex-OneNAND combines SLC and MLC technologies into a single device.
SLC area provides increased reliability and speed, suitable for storing
code such as bootloader, kernel and root file system.  MLC area
provides high density and is suitable for storing user data.

SLC and MLC regions can be configured through kernel parameter.

[akpm@linux-foundation.org: export flexoand_region and onenand_addr]
Signed-off-by: Rohit Hagargundgi <h.rohit@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Vishak G <vishak.g@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2009-06-05 18:59:21 +01:00

253 lines
6.8 KiB
C

/*
* linux/drivers/mtd/onenand/onenand_bbt.c
*
* Bad Block Table support for the OneNAND driver
*
* Copyright(c) 2005 Samsung Electronics
* Kyungmin Park <kyungmin.park@samsung.com>
*
* Derived from nand_bbt.c
*
* TODO:
* Split BBT core and chip specific BBT.
*/
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/onenand.h>
#include <linux/mtd/compatmac.h>
/**
* check_short_pattern - [GENERIC] check if a pattern is in the buffer
* @param buf the buffer to search
* @param len the length of buffer to search
* @param paglen the pagelength
* @param td search pattern descriptor
*
* Check for a pattern at the given place. Used to search bad block
* tables and good / bad block identifiers. Same as check_pattern, but
* no optional empty check and the pattern is expected to start
* at offset 0.
*
*/
static int check_short_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
{
int i;
uint8_t *p = buf;
/* Compare the pattern */
for (i = 0; i < td->len; i++) {
if (p[i] != td->pattern[i])
return -1;
}
return 0;
}
/**
* create_bbt - [GENERIC] Create a bad block table by scanning the device
* @param mtd MTD device structure
* @param buf temporary buffer
* @param bd descriptor for the good/bad block search pattern
* @param chip create the table for a specific chip, -1 read all chips.
* Applies only if NAND_BBT_PERCHIP option is set
*
* Create a bad block table by scanning the device
* for the given good/bad block identify pattern
*/
static int create_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd, int chip)
{
struct onenand_chip *this = mtd->priv;
struct bbm_info *bbm = this->bbm;
int i, j, numblocks, len, scanlen;
int startblock;
loff_t from;
size_t readlen, ooblen;
struct mtd_oob_ops ops;
int rgn;
printk(KERN_INFO "Scanning device for bad blocks\n");
len = 2;
/* We need only read few bytes from the OOB area */
scanlen = ooblen = 0;
readlen = bd->len;
/* chip == -1 case only */
/* Note that numblocks is 2 * (real numblocks) here;
* see i += 2 below as it makses shifting and masking less painful
*/
numblocks = this->chipsize >> (bbm->bbt_erase_shift - 1);
startblock = 0;
from = 0;
ops.mode = MTD_OOB_PLACE;
ops.ooblen = readlen;
ops.oobbuf = buf;
ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0;
for (i = startblock; i < numblocks; ) {
int ret;
for (j = 0; j < len; j++) {
/* No need to read pages fully,
* just read required OOB bytes */
ret = onenand_bbt_read_oob(mtd, from + j * mtd->writesize + bd->offs, &ops);
/* If it is a initial bad block, just ignore it */
if (ret == ONENAND_BBT_READ_FATAL_ERROR)
return -EIO;
if (ret || check_short_pattern(&buf[j * scanlen], scanlen, mtd->writesize, bd)) {
bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);
printk(KERN_WARNING "Bad eraseblock %d at 0x%08x\n",
i >> 1, (unsigned int) from);
mtd->ecc_stats.badblocks++;
break;
}
}
i += 2;
if (FLEXONENAND(this)) {
rgn = flexonenand_region(mtd, from);
from += mtd->eraseregions[rgn].erasesize;
} else
from += (1 << bbm->bbt_erase_shift);
}
return 0;
}
/**
* onenand_memory_bbt - [GENERIC] create a memory based bad block table
* @param mtd MTD device structure
* @param bd descriptor for the good/bad block search pattern
*
* The function creates a memory based bbt by scanning the device
* for manufacturer / software marked good / bad blocks
*/
static inline int onenand_memory_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd)
{
struct onenand_chip *this = mtd->priv;
bd->options &= ~NAND_BBT_SCANEMPTY;
return create_bbt(mtd, this->page_buf, bd, -1);
}
/**
* onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad
* @param mtd MTD device structure
* @param offs offset in the device
* @param allowbbt allow access to bad block table region
*/
static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
{
struct onenand_chip *this = mtd->priv;
struct bbm_info *bbm = this->bbm;
int block;
uint8_t res;
/* Get block number * 2 */
block = (int) (onenand_block(this, offs) << 1);
res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03;
DEBUG(MTD_DEBUG_LEVEL2, "onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n",
(unsigned int) offs, block >> 1, res);
switch ((int) res) {
case 0x00: return 0;
case 0x01: return 1;
case 0x02: return allowbbt ? 0 : 1;
}
return 1;
}
/**
* onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s)
* @param mtd MTD device structure
* @param bd descriptor for the good/bad block search pattern
*
* The function checks, if a bad block table(s) is/are already
* available. If not it scans the device for manufacturer
* marked good / bad blocks and writes the bad block table(s) to
* the selected place.
*
* The bad block table memory is allocated here. It is freed
* by the onenand_release function.
*
*/
int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
{
struct onenand_chip *this = mtd->priv;
struct bbm_info *bbm = this->bbm;
int len, ret = 0;
len = this->chipsize >> (this->erase_shift + 2);
/* Allocate memory (2bit per block) and clear the memory bad block table */
bbm->bbt = kzalloc(len, GFP_KERNEL);
if (!bbm->bbt) {
printk(KERN_ERR "onenand_scan_bbt: Out of memory\n");
return -ENOMEM;
}
/* Set the bad block position */
bbm->badblockpos = ONENAND_BADBLOCK_POS;
/* Set erase shift */
bbm->bbt_erase_shift = this->erase_shift;
if (!bbm->isbad_bbt)
bbm->isbad_bbt = onenand_isbad_bbt;
/* Scan the device to build a memory based bad block table */
if ((ret = onenand_memory_bbt(mtd, bd))) {
printk(KERN_ERR "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n");
kfree(bbm->bbt);
bbm->bbt = NULL;
}
return ret;
}
/*
* Define some generic bad / good block scan pattern which are used
* while scanning a device for factory marked good / bad blocks.
*/
static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
static struct nand_bbt_descr largepage_memorybased = {
.options = 0,
.offs = 0,
.len = 2,
.pattern = scan_ff_pattern,
};
/**
* onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device
* @param mtd MTD device structure
*
* This function selects the default bad block table
* support for the device and calls the onenand_scan_bbt function
*/
int onenand_default_bbt(struct mtd_info *mtd)
{
struct onenand_chip *this = mtd->priv;
struct bbm_info *bbm;
this->bbm = kzalloc(sizeof(struct bbm_info), GFP_KERNEL);
if (!this->bbm)
return -ENOMEM;
bbm = this->bbm;
/* 1KB page has same configuration as 2KB page */
if (!bbm->badblock_pattern)
bbm->badblock_pattern = &largepage_memorybased;
return onenand_scan_bbt(mtd, bbm->badblock_pattern);
}
EXPORT_SYMBOL(onenand_scan_bbt);
EXPORT_SYMBOL(onenand_default_bbt);