diff options
| -rw-r--r-- | drivers/mtd/onenand/onenand_bbt.c | 246 | ||||
| -rw-r--r-- | include/linux/mtd/bbm.h | 122 |
2 files changed, 368 insertions, 0 deletions
diff --git a/drivers/mtd/onenand/onenand_bbt.c b/drivers/mtd/onenand/onenand_bbt.c new file mode 100644 index 0000000..f40190f --- /dev/null +++ b/drivers/mtd/onenand/onenand_bbt.c @@ -0,0 +1,246 @@ +/* + * 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; + + printk(KERN_INFO "Scanning device for bad blocks\n"); + + len = 1; + + /* 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 = mtd->size >> (bbm->bbt_erase_shift - 1); + startblock = 0; + from = 0; + + for (i = startblock; i < numblocks; ) { + int ret; + + for (j = 0; j < len; j++) { + size_t retlen; + + /* No need to read pages fully, + * just read required OOB bytes */ + ret = mtd->read_oob(mtd, from + j * mtd->oobblock + bd->offs, + readlen, &retlen, &buf[0]); + + if (ret) + return ret; + + if (check_short_pattern(&buf[j * scanlen], scanlen, mtd->oobblock, bd)) { + bbm->bbt[i >> 3] |= 0x03 << (i & 0x6); + printk(KERN_WARNING "Bad eraseblock %d at 0x%08x\n", + i >> 1, (unsigned int) from); + break; + } + } + i += 2; + 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) +{ + unsigned char data_buf[MAX_ONENAND_PAGESIZE]; + + bd->options &= ~NAND_BBT_SCANEMPTY; + return create_bbt(mtd, data_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) (offs >> (bbm->bbt_erase_shift - 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 must be freed + * by calling the onenand_free_bbt 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 = mtd->size >> (this->erase_shift + 2); + /* Allocate memory (2bit per block) */ + bbm->bbt = kmalloc(len, GFP_KERNEL); + if (!bbm->bbt) { + printk(KERN_ERR "onenand_scan_bbt: Out of memory\n"); + return -ENOMEM; + } + /* Clear the memory bad block table */ + memset(bbm->bbt, 0x00, len); + + /* 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 = kmalloc(sizeof(struct bbm_info), GFP_KERNEL); + if (!this->bbm) + return -ENOMEM; + + bbm = this->bbm; + + memset(bbm, 0, sizeof(struct bbm_info)); + + /* 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); diff --git a/include/linux/mtd/bbm.h b/include/linux/mtd/bbm.h new file mode 100644 index 0000000..92b42cb --- /dev/null +++ b/include/linux/mtd/bbm.h @@ -0,0 +1,122 @@ +/* + * linux/include/linux/mtd/bbm.h + * + * NAND family Bad Block Management (BBM) header file + * - Bad Block Table (BBT) implementation + * + * Copyright (c) 2005 Samsung Electronics + * Kyungmin Park <kyungmin.park@samsung.com> + * + * Copyright (c) 2000-2005 + * Thomas Gleixner <tglx@linuxtronix.de> + * + */ +#ifndef __LINUX_MTD_BBM_H +#define __LINUX_MTD_BBM_H + +/* The maximum number of NAND chips in an array */ +#define NAND_MAX_CHIPS 8 + +/** + * struct nand_bbt_descr - bad block table descriptor + * @param options options for this descriptor + * @param pages the page(s) where we find the bbt, used with + * option BBT_ABSPAGE when bbt is searched, + * then we store the found bbts pages here. + * Its an array and supports up to 8 chips now + * @param offs offset of the pattern in the oob area of the page + * @param veroffs offset of the bbt version counter in the oob are of the page + * @param version version read from the bbt page during scan + * @param len length of the pattern, if 0 no pattern check is performed + * @param maxblocks maximum number of blocks to search for a bbt. This number of + * blocks is reserved at the end of the device + * where the tables are written. + * @param reserved_block_code if non-0, this pattern denotes a reserved + * (rather than bad) block in the stored bbt + * @param pattern pattern to identify bad block table or factory marked + * good / bad blocks, can be NULL, if len = 0 + * + * Descriptor for the bad block table marker and the descriptor for the + * pattern which identifies good and bad blocks. The assumption is made + * that the pattern and the version count are always located in the oob area + * of the first block. + */ +struct nand_bbt_descr { + int options; + int pages[NAND_MAX_CHIPS]; + int offs; + int veroffs; + uint8_t version[NAND_MAX_CHIPS]; + int len; + int maxblocks; + int reserved_block_code; + uint8_t *pattern; +}; + +/* Options for the bad block table descriptors */ + +/* The number of bits used per block in the bbt on the device */ +#define NAND_BBT_NRBITS_MSK 0x0000000F +#define NAND_BBT_1BIT 0x00000001 +#define NAND_BBT_2BIT 0x00000002 +#define NAND_BBT_4BIT 0x00000004 +#define NAND_BBT_8BIT 0x00000008 +/* The bad block table is in the last good block of the device */ +#define NAND_BBT_LASTBLOCK 0x00000010 +/* The bbt is at the given page, else we must scan for the bbt */ +#define NAND_BBT_ABSPAGE 0x00000020 +/* The bbt is at the given page, else we must scan for the bbt */ +#define NAND_BBT_SEARCH 0x00000040 +/* bbt is stored per chip on multichip devices */ +#define NAND_BBT_PERCHIP 0x00000080 +/* bbt has a version counter at offset veroffs */ +#define NAND_BBT_VERSION 0x00000100 +/* Create a bbt if none axists */ +#define NAND_BBT_CREATE 0x00000200 +/* Search good / bad pattern through all pages of a block */ +#define NAND_BBT_SCANALLPAGES 0x00000400 +/* Scan block empty during good / bad block scan */ +#define NAND_BBT_SCANEMPTY 0x00000800 +/* Write bbt if neccecary */ +#define NAND_BBT_WRITE 0x00001000 +/* Read and write back block contents when writing bbt */ +#define NAND_BBT_SAVECONTENT 0x00002000 +/* Search good / bad pattern on the first and the second page */ +#define NAND_BBT_SCAN2NDPAGE 0x00004000 + +/* The maximum number of blocks to scan for a bbt */ +#define NAND_BBT_SCAN_MAXBLOCKS 4 + +/* + * Constants for oob configuration + */ +#define ONENAND_BADBLOCK_POS 0 + +/** + * struct bbt_info - [GENERIC] Bad Block Table data structure + * @param bbt_erase_shift [INTERN] number of address bits in a bbt entry + * @param badblockpos [INTERN] position of the bad block marker in the oob area + * @param bbt [INTERN] bad block table pointer + * @param badblock_pattern [REPLACEABLE] bad block scan pattern used for initial bad block scan + * @param priv [OPTIONAL] pointer to private bbm date + */ +struct bbm_info { + int bbt_erase_shift; + int badblockpos; + int options; + + uint8_t *bbt; + + int (*isbad_bbt)(struct mtd_info *mtd, loff_t ofs, int allowbbt); + + /* TODO Add more NAND specific fileds */ + struct nand_bbt_descr *badblock_pattern; + + void *priv; +}; + +/* OneNAND BBT interface */ +extern int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd); +extern int onenand_default_bbt(struct mtd_info *mtd); + +#endif /* __LINUX_MTD_BBM_H */ |
