1 /*
2 * linux/drivers/mtd/onenand/onenand_bbt.c
3 *
4 * Bad Block Table support for the OneNAND driver
5 *
6 * Copyright(c) 2005 Samsung Electronics
7 * Kyungmin Park <kyungmin.park@samsung.com>
8 *
9 * Derived from nand_bbt.c
10 *
11 * TODO:
12 * Split BBT core and chip specific BBT.
13 */
14
15 #include <linux/slab.h>
16 #include <linux/mtd/mtd.h>
17 #include <linux/mtd/onenand.h>
18 #include <linux/export.h>
19
20 /**
21 * check_short_pattern - [GENERIC] check if a pattern is in the buffer
22 * @param buf the buffer to search
23 * @param len the length of buffer to search
24 * @param paglen the pagelength
25 * @param td search pattern descriptor
26 *
27 * Check for a pattern at the given place. Used to search bad block
28 * tables and good / bad block identifiers. Same as check_pattern, but
29 * no optional empty check and the pattern is expected to start
30 * at offset 0.
31 *
32 */
check_short_pattern(uint8_t * buf,int len,int paglen,struct nand_bbt_descr * td)33 static int check_short_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
34 {
35 int i;
36 uint8_t *p = buf;
37
38 /* Compare the pattern */
39 for (i = 0; i < td->len; i++) {
40 if (p[i] != td->pattern[i])
41 return -1;
42 }
43 return 0;
44 }
45
46 /**
47 * create_bbt - [GENERIC] Create a bad block table by scanning the device
48 * @param mtd MTD device structure
49 * @param buf temporary buffer
50 * @param bd descriptor for the good/bad block search pattern
51 * @param chip create the table for a specific chip, -1 read all chips.
52 * Applies only if NAND_BBT_PERCHIP option is set
53 *
54 * Create a bad block table by scanning the device
55 * for the given good/bad block identify pattern
56 */
create_bbt(struct mtd_info * mtd,uint8_t * buf,struct nand_bbt_descr * bd,int chip)57 static int create_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd, int chip)
58 {
59 struct onenand_chip *this = mtd->priv;
60 struct bbm_info *bbm = this->bbm;
61 int i, j, numblocks, len, scanlen;
62 int startblock;
63 loff_t from;
64 size_t readlen, ooblen;
65 struct mtd_oob_ops ops;
66 int rgn;
67
68 printk(KERN_INFO "Scanning device for bad blocks\n");
69
70 len = 2;
71
72 /* We need only read few bytes from the OOB area */
73 scanlen = ooblen = 0;
74 readlen = bd->len;
75
76 /* chip == -1 case only */
77 /* Note that numblocks is 2 * (real numblocks) here;
78 * see i += 2 below as it makses shifting and masking less painful
79 */
80 numblocks = this->chipsize >> (bbm->bbt_erase_shift - 1);
81 startblock = 0;
82 from = 0;
83
84 ops.mode = MTD_OPS_PLACE_OOB;
85 ops.ooblen = readlen;
86 ops.oobbuf = buf;
87 ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0;
88
89 for (i = startblock; i < numblocks; ) {
90 int ret;
91
92 for (j = 0; j < len; j++) {
93 /* No need to read pages fully,
94 * just read required OOB bytes */
95 ret = onenand_bbt_read_oob(mtd,
96 from + j * this->writesize + bd->offs, &ops);
97
98 /* If it is a initial bad block, just ignore it */
99 if (ret == ONENAND_BBT_READ_FATAL_ERROR)
100 return -EIO;
101
102 if (ret || check_short_pattern(&buf[j * scanlen],
103 scanlen, this->writesize, bd)) {
104 bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);
105 printk(KERN_INFO "OneNAND eraseblock %d is an "
106 "initial bad block\n", i >> 1);
107 mtd->ecc_stats.badblocks++;
108 break;
109 }
110 }
111 i += 2;
112
113 if (FLEXONENAND(this)) {
114 rgn = flexonenand_region(mtd, from);
115 from += mtd->eraseregions[rgn].erasesize;
116 } else
117 from += (1 << bbm->bbt_erase_shift);
118 }
119
120 return 0;
121 }
122
123
124 /**
125 * onenand_memory_bbt - [GENERIC] create a memory based bad block table
126 * @param mtd MTD device structure
127 * @param bd descriptor for the good/bad block search pattern
128 *
129 * The function creates a memory based bbt by scanning the device
130 * for manufacturer / software marked good / bad blocks
131 */
onenand_memory_bbt(struct mtd_info * mtd,struct nand_bbt_descr * bd)132 static inline int onenand_memory_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd)
133 {
134 struct onenand_chip *this = mtd->priv;
135
136 return create_bbt(mtd, this->page_buf, bd, -1);
137 }
138
139 /**
140 * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad
141 * @param mtd MTD device structure
142 * @param offs offset in the device
143 * @param allowbbt allow access to bad block table region
144 */
onenand_isbad_bbt(struct mtd_info * mtd,loff_t offs,int allowbbt)145 static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
146 {
147 struct onenand_chip *this = mtd->priv;
148 struct bbm_info *bbm = this->bbm;
149 int block;
150 uint8_t res;
151
152 /* Get block number * 2 */
153 block = (int) (onenand_block(this, offs) << 1);
154 res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03;
155
156 pr_debug("onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n",
157 (unsigned int) offs, block >> 1, res);
158
159 switch ((int) res) {
160 case 0x00: return 0;
161 case 0x01: return 1;
162 case 0x02: return allowbbt ? 0 : 1;
163 }
164
165 return 1;
166 }
167
168 /**
169 * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s)
170 * @param mtd MTD device structure
171 * @param bd descriptor for the good/bad block search pattern
172 *
173 * The function checks, if a bad block table(s) is/are already
174 * available. If not it scans the device for manufacturer
175 * marked good / bad blocks and writes the bad block table(s) to
176 * the selected place.
177 *
178 * The bad block table memory is allocated here. It is freed
179 * by the onenand_release function.
180 *
181 */
onenand_scan_bbt(struct mtd_info * mtd,struct nand_bbt_descr * bd)182 static int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
183 {
184 struct onenand_chip *this = mtd->priv;
185 struct bbm_info *bbm = this->bbm;
186 int len, ret = 0;
187
188 len = this->chipsize >> (this->erase_shift + 2);
189 /* Allocate memory (2bit per block) and clear the memory bad block table */
190 bbm->bbt = kzalloc(len, GFP_KERNEL);
191 if (!bbm->bbt)
192 return -ENOMEM;
193
194 /* Set the bad block position */
195 bbm->badblockpos = ONENAND_BADBLOCK_POS;
196
197 /* Set erase shift */
198 bbm->bbt_erase_shift = this->erase_shift;
199
200 if (!bbm->isbad_bbt)
201 bbm->isbad_bbt = onenand_isbad_bbt;
202
203 /* Scan the device to build a memory based bad block table */
204 if ((ret = onenand_memory_bbt(mtd, bd))) {
205 printk(KERN_ERR "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n");
206 kfree(bbm->bbt);
207 bbm->bbt = NULL;
208 }
209
210 return ret;
211 }
212
213 /*
214 * Define some generic bad / good block scan pattern which are used
215 * while scanning a device for factory marked good / bad blocks.
216 */
217 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
218
219 static struct nand_bbt_descr largepage_memorybased = {
220 .options = 0,
221 .offs = 0,
222 .len = 2,
223 .pattern = scan_ff_pattern,
224 };
225
226 /**
227 * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device
228 * @param mtd MTD device structure
229 *
230 * This function selects the default bad block table
231 * support for the device and calls the onenand_scan_bbt function
232 */
onenand_default_bbt(struct mtd_info * mtd)233 int onenand_default_bbt(struct mtd_info *mtd)
234 {
235 struct onenand_chip *this = mtd->priv;
236 struct bbm_info *bbm;
237
238 this->bbm = kzalloc(sizeof(struct bbm_info), GFP_KERNEL);
239 if (!this->bbm)
240 return -ENOMEM;
241
242 bbm = this->bbm;
243
244 /* 1KB page has same configuration as 2KB page */
245 if (!bbm->badblock_pattern)
246 bbm->badblock_pattern = &largepage_memorybased;
247
248 return onenand_scan_bbt(mtd, bbm->badblock_pattern);
249 }
250