1 /*
2 * linux/drivers/mtd/onenand/onenand_bbt.c
3 *
4 * Bad Block Table support for the OneNAND driver
5 *
6 * Copyright(c) 2005-2008 Samsung Electronics
7 * Kyungmin Park <kyungmin.park@samsung.com>
8 *
9 * TODO:
10 * Split BBT core and chip specific BBT.
11 *
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.
15 */
16
17 #include <common.h>
18 #include <log.h>
19 #include <linux/compat.h>
20 #include <linux/mtd/mtd.h>
21 #include <linux/mtd/onenand.h>
22 #include <malloc.h>
23
24 #include <linux/errno.h>
25
26 /**
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
32 *
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
36 * at offset 0.
37 */
check_short_pattern(uint8_t * buf,int len,int paglen,struct nand_bbt_descr * td)38 static int check_short_pattern(uint8_t * buf, int len, int paglen,
39 struct nand_bbt_descr *td)
40 {
41 int i;
42 uint8_t *p = buf;
43
44 /* Compare the pattern */
45 for (i = 0; i < td->len; i++) {
46 if (p[i] != td->pattern[i])
47 return -1;
48 }
49 return 0;
50 }
51
52 /**
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
59 *
60 * Create a bad block table by scanning the device
61 * for the given good/bad block identify pattern
62 */
create_bbt(struct mtd_info * mtd,uint8_t * buf,struct nand_bbt_descr * bd,int chip)63 static int create_bbt(struct mtd_info *mtd, uint8_t * buf,
64 struct nand_bbt_descr *bd, int chip)
65 {
66 struct onenand_chip *this = mtd->priv;
67 struct bbm_info *bbm = this->bbm;
68 int i, j, numblocks, len, scanlen;
69 int startblock;
70 loff_t from;
71 size_t readlen, ooblen;
72 struct mtd_oob_ops ops;
73 int rgn;
74
75 printk(KERN_INFO "Scanning device for bad blocks\n");
76
77 len = 1;
78
79 /* We need only read few bytes from the OOB area */
80 scanlen = ooblen = 0;
81 readlen = bd->len;
82
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
86 */
87 numblocks = this->chipsize >> (bbm->bbt_erase_shift - 1);
88 startblock = 0;
89 from = 0;
90
91 ops.mode = MTD_OPS_PLACE_OOB;
92 ops.ooblen = readlen;
93 ops.oobbuf = buf;
94 ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0;
95
96 for (i = startblock; i < numblocks;) {
97 int ret;
98
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 +
104 bd->offs, &ops);
105
106 /* If it is a initial bad block, just ignore it */
107 if (ret == ONENAND_BBT_READ_FATAL_ERROR)
108 return -EIO;
109
110 if (ret || check_short_pattern
111 (&buf[j * scanlen], scanlen, mtd->writesize, bd)) {
112 bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);
113 printk(KERN_WARNING
114 "Bad eraseblock %d at 0x%08x\n", i >> 1,
115 (unsigned int)from);
116 break;
117 }
118 }
119 i += 2;
120
121 if (FLEXONENAND(this)) {
122 rgn = flexonenand_region(mtd, from);
123 from += mtd->eraseregions[rgn].erasesize;
124 } else
125 from += (1 << bbm->bbt_erase_shift);
126 }
127
128 return 0;
129 }
130
131 /**
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
135 *
136 * The function creates a memory based bbt by scanning the device
137 * for manufacturer / software marked good / bad blocks
138 */
onenand_memory_bbt(struct mtd_info * mtd,struct nand_bbt_descr * bd)139 static inline int onenand_memory_bbt(struct mtd_info *mtd,
140 struct nand_bbt_descr *bd)
141 {
142 unsigned char data_buf[MAX_ONENAND_PAGESIZE];
143
144 return create_bbt(mtd, data_buf, bd, -1);
145 }
146
147 /**
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
152 */
onenand_isbad_bbt(struct mtd_info * mtd,loff_t offs,int allowbbt)153 static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
154 {
155 struct onenand_chip *this = mtd->priv;
156 struct bbm_info *bbm = this->bbm;
157 int block;
158 uint8_t res;
159
160 /* Get block number * 2 */
161 block = (int) (onenand_block(this, offs) << 1);
162 res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03;
163
164 pr_debug("onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n",
165 (unsigned int)offs, block >> 1, res);
166
167 switch ((int)res) {
168 case 0x00:
169 return 0;
170 case 0x01:
171 return 1;
172 case 0x02:
173 return allowbbt ? 0 : 1;
174 }
175
176 return 1;
177 }
178
179 /**
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
183 *
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.
188 *
189 * The bad block table memory is allocated here. It must be freed
190 * by calling the onenand_free_bbt function.
191 *
192 */
onenand_scan_bbt(struct mtd_info * mtd,struct nand_bbt_descr * bd)193 int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
194 {
195 struct onenand_chip *this = mtd->priv;
196 struct bbm_info *bbm = this->bbm;
197 int len, ret = 0;
198
199 len = this->chipsize >> (this->erase_shift + 2);
200 /* Allocate memory (2bit per block) */
201 bbm->bbt = malloc(len);
202 if (!bbm->bbt)
203 return -ENOMEM;
204 /* Clear the memory bad block table */
205 memset(bbm->bbt, 0x00, len);
206
207 /* Set the bad block position */
208 bbm->badblockpos = ONENAND_BADBLOCK_POS;
209
210 /* Set erase shift */
211 bbm->bbt_erase_shift = this->erase_shift;
212
213 if (!bbm->isbad_bbt)
214 bbm->isbad_bbt = onenand_isbad_bbt;
215
216 /* Scan the device to build a memory based bad block table */
217 if ((ret = onenand_memory_bbt(mtd, bd))) {
218 printk(KERN_ERR
219 "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n");
220 free(bbm->bbt);
221 bbm->bbt = NULL;
222 }
223
224 return ret;
225 }
226
227 /*
228 * Define some generic bad / good block scan pattern which are used
229 * while scanning a device for factory marked good / bad blocks.
230 */
231 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
232
233 static struct nand_bbt_descr largepage_memorybased = {
234 .options = 0,
235 .offs = 0,
236 .len = 2,
237 .pattern = scan_ff_pattern,
238 };
239
240 /**
241 * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device
242 * @param mtd MTD device structure
243 *
244 * This function selects the default bad block table
245 * support for the device and calls the onenand_scan_bbt function
246 */
onenand_default_bbt(struct mtd_info * mtd)247 int onenand_default_bbt(struct mtd_info *mtd)
248 {
249 struct onenand_chip *this = mtd->priv;
250 struct bbm_info *bbm;
251
252 this->bbm = malloc(sizeof(struct bbm_info));
253 if (!this->bbm)
254 return -ENOMEM;
255
256 bbm = this->bbm;
257
258 memset(bbm, 0, sizeof(struct bbm_info));
259
260 /* 1KB page has same configuration as 2KB page */
261 if (!bbm->badblock_pattern)
262 bbm->badblock_pattern = &largepage_memorybased;
263
264 return onenand_scan_bbt(mtd, bbm->badblock_pattern);
265 }
266