2 * linux/drivers/mtd/onenand/onenand_bbt.c
4 * Bad Block Table support for the OneNAND driver
6 * Copyright(c) 2005-2008 Samsung Electronics
7 * Kyungmin Park <kyungmin.park@samsung.com>
10 * Split BBT core and chip specific BBT.
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
19 #include <linux/compat.h>
20 #include <linux/mtd/mtd.h>
21 #include <linux/mtd/onenand.h>
24 #include <linux/errno.h>
27 * check_short_pattern - [GENERIC] check if a pattern is in the buffer
28 * @param buf the buffer to search
29 * @param len the length of buffer to search
30 * @param paglen the pagelength
31 * @param td search pattern descriptor
33 * Check for a pattern at the given place. Used to search bad block
34 * tables and good / bad block identifiers. Same as check_pattern, but
35 * no optional empty check and the pattern is expected to start
38 static int check_short_pattern(uint8_t * buf, int len, int paglen,
39 struct nand_bbt_descr *td)
44 /* Compare the pattern */
45 for (i = 0; i < td->len; i++) {
46 if (p[i] != td->pattern[i])
53 * create_bbt - [GENERIC] Create a bad block table by scanning the device
54 * @param mtd MTD device structure
55 * @param buf temporary buffer
56 * @param bd descriptor for the good/bad block search pattern
57 * @param chip create the table for a specific chip, -1 read all chips.
58 * Applies only if NAND_BBT_PERCHIP option is set
60 * Create a bad block table by scanning the device
61 * for the given good/bad block identify pattern
63 static int create_bbt(struct mtd_info *mtd, uint8_t * buf,
64 struct nand_bbt_descr *bd, int chip)
66 struct onenand_chip *this = mtd->priv;
67 struct bbm_info *bbm = this->bbm;
68 int i, j, numblocks, len, scanlen;
71 size_t readlen, ooblen;
72 struct mtd_oob_ops ops;
75 printk(KERN_INFO "Scanning device for bad blocks\n");
79 /* We need only read few bytes from the OOB area */
83 /* chip == -1 case only */
84 /* Note that numblocks is 2 * (real numblocks) here;
85 * see i += 2 below as it makses shifting and masking less painful
87 numblocks = this->chipsize >> (bbm->bbt_erase_shift - 1);
91 ops.mode = MTD_OPS_PLACE_OOB;
94 ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0;
96 for (i = startblock; i < numblocks;) {
99 for (j = 0; j < len; j++) {
100 /* No need to read pages fully,
101 * just read required OOB bytes */
102 ret = onenand_bbt_read_oob(mtd,
103 from + j * mtd->writesize +
106 /* If it is a initial bad block, just ignore it */
107 if (ret == ONENAND_BBT_READ_FATAL_ERROR)
110 if (ret || check_short_pattern
111 (&buf[j * scanlen], scanlen, mtd->writesize, bd)) {
112 bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);
114 "Bad eraseblock %d at 0x%08x\n", i >> 1,
121 if (FLEXONENAND(this)) {
122 rgn = flexonenand_region(mtd, from);
123 from += mtd->eraseregions[rgn].erasesize;
125 from += (1 << bbm->bbt_erase_shift);
132 * onenand_memory_bbt - [GENERIC] create a memory based bad block table
133 * @param mtd MTD device structure
134 * @param bd descriptor for the good/bad block search pattern
136 * The function creates a memory based bbt by scanning the device
137 * for manufacturer / software marked good / bad blocks
139 static inline int onenand_memory_bbt(struct mtd_info *mtd,
140 struct nand_bbt_descr *bd)
142 unsigned char data_buf[MAX_ONENAND_PAGESIZE];
144 return create_bbt(mtd, data_buf, bd, -1);
148 * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad
149 * @param mtd MTD device structure
150 * @param offs offset in the device
151 * @param allowbbt allow access to bad block table region
153 static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
155 struct onenand_chip *this = mtd->priv;
156 struct bbm_info *bbm = this->bbm;
160 /* Get block number * 2 */
161 block = (int) (onenand_block(this, offs) << 1);
162 res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03;
164 pr_debug("onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n",
165 (unsigned int)offs, block >> 1, res);
173 return allowbbt ? 0 : 1;
180 * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s)
181 * @param mtd MTD device structure
182 * @param bd descriptor for the good/bad block search pattern
184 * The function checks, if a bad block table(s) is/are already
185 * available. If not it scans the device for manufacturer
186 * marked good / bad blocks and writes the bad block table(s) to
187 * the selected place.
189 * The bad block table memory is allocated here. It must be freed
190 * by calling the onenand_free_bbt function.
193 int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
195 struct onenand_chip *this = mtd->priv;
196 struct bbm_info *bbm = this->bbm;
199 len = this->chipsize >> (this->erase_shift + 2);
200 /* Allocate memory (2bit per block) */
201 bbm->bbt = malloc(len);
204 /* Clear the memory bad block table */
205 memset(bbm->bbt, 0x00, len);
207 /* Set the bad block position */
208 bbm->badblockpos = ONENAND_BADBLOCK_POS;
210 /* Set erase shift */
211 bbm->bbt_erase_shift = this->erase_shift;
214 bbm->isbad_bbt = onenand_isbad_bbt;
216 /* Scan the device to build a memory based bad block table */
217 if ((ret = onenand_memory_bbt(mtd, bd))) {
219 "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n");
228 * Define some generic bad / good block scan pattern which are used
229 * while scanning a device for factory marked good / bad blocks.
231 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
233 static struct nand_bbt_descr largepage_memorybased = {
237 .pattern = scan_ff_pattern,
241 * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device
242 * @param mtd MTD device structure
244 * This function selects the default bad block table
245 * support for the device and calls the onenand_scan_bbt function
247 int onenand_default_bbt(struct mtd_info *mtd)
249 struct onenand_chip *this = mtd->priv;
250 struct bbm_info *bbm;
252 this->bbm = malloc(sizeof(struct bbm_info));
258 memset(bbm, 0, sizeof(struct bbm_info));
260 /* 1KB page has same configuration as 2KB page */
261 if (!bbm->badblock_pattern)
262 bbm->badblock_pattern = &largepage_memorybased;
264 return onenand_scan_bbt(mtd, bbm->badblock_pattern);