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-rw-r--r--drivers/mtd/onenand/onenand_bbt.c246
1 files changed, 246 insertions, 0 deletions
diff --git a/drivers/mtd/onenand/onenand_bbt.c b/drivers/mtd/onenand/onenand_bbt.c
new file mode 100644
index 000000000000..f40190f499e1
--- /dev/null
+++ b/drivers/mtd/onenand/onenand_bbt.c
@@ -0,0 +1,246 @@
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/mtd/compatmac.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 */
33static 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 */
57static 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
66 printk(KERN_INFO "Scanning device for bad blocks\n");
67
68 len = 1;
69
70 /* We need only read few bytes from the OOB area */
71 scanlen = ooblen = 0;
72 readlen = bd->len;
73
74 /* chip == -1 case only */
75 /* Note that numblocks is 2 * (real numblocks) here;
76 * see i += 2 below as it makses shifting and masking less painful
77 */
78 numblocks = mtd->size >> (bbm->bbt_erase_shift - 1);
79 startblock = 0;
80 from = 0;
81
82 for (i = startblock; i < numblocks; ) {
83 int ret;
84
85 for (j = 0; j < len; j++) {
86 size_t retlen;
87
88 /* No need to read pages fully,
89 * just read required OOB bytes */
90 ret = mtd->read_oob(mtd, from + j * mtd->oobblock + bd->offs,
91 readlen, &retlen, &buf[0]);
92
93 if (ret)
94 return ret;
95
96 if (check_short_pattern(&buf[j * scanlen], scanlen, mtd->oobblock, bd)) {
97 bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);
98 printk(KERN_WARNING "Bad eraseblock %d at 0x%08x\n",
99 i >> 1, (unsigned int) from);
100 break;
101 }
102 }
103 i += 2;
104 from += (1 << bbm->bbt_erase_shift);
105 }
106
107 return 0;
108}
109
110
111/**
112 * onenand_memory_bbt - [GENERIC] create a memory based bad block table
113 * @param mtd MTD device structure
114 * @param bd descriptor for the good/bad block search pattern
115 *
116 * The function creates a memory based bbt by scanning the device
117 * for manufacturer / software marked good / bad blocks
118 */
119static inline int onenand_memory_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd)
120{
121 unsigned char data_buf[MAX_ONENAND_PAGESIZE];
122
123 bd->options &= ~NAND_BBT_SCANEMPTY;
124 return create_bbt(mtd, data_buf, bd, -1);
125}
126
127/**
128 * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad
129 * @param mtd MTD device structure
130 * @param offs offset in the device
131 * @param allowbbt allow access to bad block table region
132 */
133static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
134{
135 struct onenand_chip *this = mtd->priv;
136 struct bbm_info *bbm = this->bbm;
137 int block;
138 uint8_t res;
139
140 /* Get block number * 2 */
141 block = (int) (offs >> (bbm->bbt_erase_shift - 1));
142 res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03;
143
144 DEBUG(MTD_DEBUG_LEVEL2, "onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n",
145 (unsigned int) offs, block >> 1, res);
146
147 switch ((int) res) {
148 case 0x00: return 0;
149 case 0x01: return 1;
150 case 0x02: return allowbbt ? 0 : 1;
151 }
152
153 return 1;
154}
155
156/**
157 * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s)
158 * @param mtd MTD device structure
159 * @param bd descriptor for the good/bad block search pattern
160 *
161 * The function checks, if a bad block table(s) is/are already
162 * available. If not it scans the device for manufacturer
163 * marked good / bad blocks and writes the bad block table(s) to
164 * the selected place.
165 *
166 * The bad block table memory is allocated here. It must be freed
167 * by calling the onenand_free_bbt function.
168 *
169 */
170int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
171{
172 struct onenand_chip *this = mtd->priv;
173 struct bbm_info *bbm = this->bbm;
174 int len, ret = 0;
175
176 len = mtd->size >> (this->erase_shift + 2);
177 /* Allocate memory (2bit per block) */
178 bbm->bbt = kmalloc(len, GFP_KERNEL);
179 if (!bbm->bbt) {
180 printk(KERN_ERR "onenand_scan_bbt: Out of memory\n");
181 return -ENOMEM;
182 }
183 /* Clear the memory bad block table */
184 memset(bbm->bbt, 0x00, len);
185
186 /* Set the bad block position */
187 bbm->badblockpos = ONENAND_BADBLOCK_POS;
188
189 /* Set erase shift */
190 bbm->bbt_erase_shift = this->erase_shift;
191
192 if (!bbm->isbad_bbt)
193 bbm->isbad_bbt = onenand_isbad_bbt;
194
195 /* Scan the device to build a memory based bad block table */
196 if ((ret = onenand_memory_bbt(mtd, bd))) {
197 printk(KERN_ERR "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n");
198 kfree(bbm->bbt);
199 bbm->bbt = NULL;
200 }
201
202 return ret;
203}
204
205/*
206 * Define some generic bad / good block scan pattern which are used
207 * while scanning a device for factory marked good / bad blocks.
208 */
209static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
210
211static struct nand_bbt_descr largepage_memorybased = {
212 .options = 0,
213 .offs = 0,
214 .len = 2,
215 .pattern = scan_ff_pattern,
216};
217
218/**
219 * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device
220 * @param mtd MTD device structure
221 *
222 * This function selects the default bad block table
223 * support for the device and calls the onenand_scan_bbt function
224 */
225int onenand_default_bbt(struct mtd_info *mtd)
226{
227 struct onenand_chip *this = mtd->priv;
228 struct bbm_info *bbm;
229
230 this->bbm = kmalloc(sizeof(struct bbm_info), GFP_KERNEL);
231 if (!this->bbm)
232 return -ENOMEM;
233
234 bbm = this->bbm;
235
236 memset(bbm, 0, sizeof(struct bbm_info));
237
238 /* 1KB page has same configuration as 2KB page */
239 if (!bbm->badblock_pattern)
240 bbm->badblock_pattern = &largepage_memorybased;
241
242 return onenand_scan_bbt(mtd, bbm->badblock_pattern);
243}
244
245EXPORT_SYMBOL(onenand_scan_bbt);
246EXPORT_SYMBOL(onenand_default_bbt);